Fact-checked by Grok 2 weeks ago

Stromal cell-derived factor 1

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, is a homeostatic CXC chemokine encoded by the CXCL12 gene on chromosome 10q11.21 that functions primarily as a chemoattractant, directing the migration and homing of hematopoietic progenitor cells, lymphocytes, and other immune effectors to specific tissues such as bone marrow and lymphoid organs. The mature protein, predominantly the α isoform comprising 68 amino acids following cleavage of a 21-amino-acid signal peptide, adopts a characteristic chemokine structure with a disordered N-terminal domain, a three-stranded antiparallel β-sheet, and a C-terminal α-helix stabilized by two disulfide bridges between conserved cysteines. Alternative splicing yields at least six isoforms (α through γ, δ, ε, and φ), with variations in the C-terminal extension influencing glycosaminoglycan binding, receptor affinity, and tissue-specific functions; for instance, CXCL12γ exhibits enhanced heparan sulfate interactions and anti-HIV activity. SDF-1 is constitutively expressed by stromal cells in bone marrow, spleen, liver, and other tissues, with levels upregulated by hypoxia-inducible factor-1 under low-oxygen conditions and downregulated by transforming growth factor-β. It exerts its effects mainly through the G protein-coupled receptor CXCR4, widely expressed on hematopoietic stem cells, endothelial cells, and neurons, activating downstream pathways including phospholipase C, phosphoinositide 3-kinase/Akt, mitogen-activated protein kinase, and Janus kinase/signal transducer and activator of transcription to promote chemotaxis, cell survival, proliferation, and adhesion. A secondary receptor, atypical chemokine receptor 3 (ACKR3/CXCR7), acts as a scavenger to modulate CXCL12 availability and signals via β-arrestin pathways, while atypical chemokine receptor 1 (ACKR1/DARC) binds dimeric forms for clearance. In physiological contexts, SDF-1 is indispensable for embryonic development and organogenesis, as Cxcl12-null mice exhibit perinatal lethality due to profound defects in cerebellar granule cell migration, cardiovascular septation, B-cell lymphopoiesis, and hematopoiesis, underscoring its role in neuronal precursor trafficking, vascular patterning, and hematopoietic stem cell retention within bone marrow niches via CXCR4-mediated adhesion to stromal cells. It maintains immune homeostasis by guiding T- and B-cell precursors during lymphopoiesis, retaining neutrophils in the bone marrow, and facilitating leukocyte recirculation for surveillance, while also driving angiogenesis through endothelial progenitor cell recruitment and vascular sprouting in collagen- or hyaluronic acid-rich matrices. Pathologically, dysregulated SDF-1/CXCR4 signaling contributes to cancer progression by promoting tumor cell metastasis to CXCL12-rich sites like bone marrow and lymph nodes, enhancing angiogenesis and immune evasion in malignancies such as multiple myeloma, breast, and pancreatic cancers, and conferring therapy resistance, as seen with CXCL12γ in myeloma. The pathway exacerbates chronic inflammation in conditions like rheumatoid arthritis (via synovial monocyte recruitment and joint neoangiogenesis) and osteoarthritis (through cartilage-degrading enzyme induction), and CXCR4 serves as a coreceptor for HIV-1 gp120 binding, enabling viral entry into CD4+ cells, though certain isoforms like CXCL12γ inhibit infection. Therapeutically, CXCR4 antagonists such as plerixafor (AMD3100) are approved for hematopoietic stem cell mobilization in transplantation by disrupting SDF-1 retention, while inhibitors like NOX-A12 target the axis in leukemia and solid tumors; additionally, localized SDF-1 delivery via biomaterials shows promise for enhancing wound healing, myocardial repair, and neural regeneration by recruiting endogenous progenitors.

Discovery and nomenclature

Discovery

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, was first cloned in 1993 by Tashiro et al. from a derived from the murine line ST2 using a signal sequence trap method designed to isolate genes encoding secreted proteins and type I membrane proteins. This approach exploited the fusion of signal sequences to a to identify novel secreted factors, revealing SDF-1 as one of several products expressed by involved in supporting hematopoiesis. In 1994, Nagasawa et al. isolated the cDNA for the human homolog of SDF-1 from a library and characterized it as a pre-B-cell growth-stimulating factor (PBSF), demonstrating its ability to promote the proliferation of early B-cell precursors when combined with interleukin-7. Subsequent studies in the mid-1990s, including work by the same group, established SDF-1 as a potent chemoattractant for lymphocytes and hematopoietic cells through functional assays such as transwell migration chambers, where SDF-1 induced directed movement across membranes. For instance, SDF-1 was shown to attract + hematopoietic progenitors at concentrations as low as 1 ng/mL, highlighting its role in marrow homing. Early investigations into SDF-1's broader biological activities in the mid-1990s also uncovered its involvement in HIV-1 infection. In 1996, Oberlin et al. identified SDF-1 as the natural ligand for the orphan receptor LESTR/fusin (later named ), showing that it potently inhibits entry of T-cell-line-adapted HIV-1 strains into target cells by competitively binding and downregulating expression. This discovery, confirmed through binding assays and viral infection inhibition experiments in CD4+ cell lines and primary lymphocytes, linked SDF-1 to antiviral defense mechanisms.

Nomenclature and isoforms

Stromal cell-derived factor 1 (SDF-1), also known as pre-B-cell growth-stimulating factor (PBSF), refers to the protein product of the CXCL12 gene, whose official nomenclature is C-X-C motif ligand 12. CXCL12 is classified within the CXC subfamily of , characterized by a conserved in which the first two residues are separated by a single intervening (the "X" in C-X-C). Alternative splicing of the CXCL12 pre-mRNA generates at least six isoforms—α, β, γ, δ, ε, and φ—that share a common N-terminal domain but vary in their C-terminal extensions, influencing their , receptor binding, and tissue localization. The α isoform, the most abundant and widely expressed variant, comprises 68 in its mature form and predominates in systemic circulation. In contrast, the β isoform features a precursor sequence of 93 , including additional C-terminal residues that enhance its and retention in extracellular matrices within tissues. The remaining isoforms (γ, δ, ε, φ) exhibit further extensions or modifications at the , contributing to isoform-specific functional properties such as differential binding.

Gene structure

Genomic location

The CXCL12 gene, encoding stromal cell-derived factor 1, is located on the long arm of human chromosome 10 at cytogenetic band 10q11.21. In the GRCh38.p14 reference assembly, the gene occupies positions 44,370,165 to 44,385,097 on the reverse (complement) strand, spanning 14,933 bp (approximately 15 kb). This positioning places CXCL12 within a gene-dense region of chromosome 10, flanked by loci involved in cellular signaling and metabolism. Certain polymorphisms in the CXCL12 gene influence disease susceptibility; for instance, the rs2839693 is associated with increased risk of , particularly in males within Chinese Han populations. A common 3' UTR polymorphism (SDF1-3'A, rs1801157) is associated with delayed progression to AIDS. The CXCL12 gene exhibits strong evolutionary across mammals and broader s, with orthologs present in over 260 species and high underscoring its fundamental role in immune cell trafficking and organ development. This conservation highlights the gene's critical architecture preserved from early vertebrate lineages.

Exon-intron organization

The CXCL12 , encoding stromal cell-derived factor 1, is structured into four s separated by three introns, spanning approximately 15 kb on the reverse strand of 10 at locus 10q11.21. The alpha isoform is encoded by three s, while the isoform includes a fourth for its extended . 1 comprises the 5' untranslated region (UTR), 2 encodes the and the majority of the core protein sequence, and s 3 and 4 contain the C-terminal coding regions as well as the 3' UTR. This organization was elucidated in the initial and of the , confirming three s for the alpha isoform as the structure despite the use of four s in certain transcripts like arising from alternative 3' . The three s flank the s at canonical splice sites (GT-AG consensus sequences), with sizable introns contributing to the overall genomic span, though exact lengths vary slightly across assemblies (e.g., ~9 kb for intron 1 and ~5 kb for intron 2 in GRCh38). primarily occurs at the 3' end, utilizing distinct sites or the fourth exon to produce multiple isoforms (e.g., CXCL12-α and CXCL12-β) with varying C-terminal extensions, while sharing the upstream exons. The promoter region, located upstream of exon 1, features binding sites for hypoxia-inducible factor 1 (HIF-1), enabling transcriptional upregulation in response to low oxygen conditions through direct HIF-1α recruitment. No common disease-causing mutations have been identified within the CXCL12 gene itself.

Protein structure

Amino acid sequence

The mature form of stromal cell-derived factor 1 (SDF-1), also known as CXCL12, in its α isoform consists of 68 amino acids following cleavage of a 21-amino-acid signal peptide from the precursor protein (UniProt P48061). The full sequence of the mature α isoform is KPVSLSYRCP CRFFESHVAR ANVKHLKILN TPNCALQIVA RLKNNNRQVC IDPKLKWIQE YLEKALNK. This protein is highly basic, with an isoelectric point (pI) of approximately 9.8, which contributes to its interaction with negatively charged molecules such as glycosaminoglycans. A defining feature of CXCL12 is its lack of the N-terminal Glu-Leu-Arg (ELR) motif present in certain pro-angiogenic CXC , classifying it as ELR-negative and distinguishing its chemotactic specificity toward lymphocytes and hematopoietic progenitors rather than neutrophils. The protein contains four conserved residues at positions 9, 11, 34, and 50 in the mature sequence, which form two intramolecular bonds (Cys9-Cys34 and Cys11-Cys50) essential for maintaining . Additionally, CXCL12 possesses a heparin-binding domain involving basic residues such as Lys24, Lys27, and Arg41, enabling its association with proteoglycans on cell surfaces. All human CXCL12 isoforms share nearly identical sequences in the core region spanning the first 68 , exhibiting over 99% identity, with variations primarily occurring in the C-terminal extensions that confer isoform-specific properties. For instance, the β isoform extends the α form by four additional residues at the .

Three-dimensional structure

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, adopts a typical fold consisting of an N-terminal disordered region, three antiparallel β-strands, and a C-terminal α-helix packed against the β-sheet. structure, spanning residues 9–65 in the mature protein, is stabilized by two bonds: one between Cys9 and Cys34, and the other between Cys11 and Cys50, which anchor the characteristic CXC and maintain the overall tertiary structure. The N-terminal loop (residues 10–21, encompassing the RFFESH sequence) is well-defined and plays a critical role in receptor activation by presenting key epitopes for binding. This monomeric conformation predominates at physiological concentrations, as determined by (NMR) spectroscopy (PDB ID: 1SDF). Crystal structures confirm the conserved fold, with three β-strands (residues 22–29, 33–40, and 43–47) and an α-helix (residues 57–65) oriented at approximately 90° to the β-sheet, alongside a short 3₁₀ helix (residues 19–22) preceding the first β-strand. Although crystallographic packing in the [N33A] mutant structure (PDB ID: 1A15) suggests a potential dimer interface, solution studies indicate that SDF-1 remains monomeric under typical conditions, with dimerization occurring only at high concentrations (>1 μM) via β-strand swapping, forming a canonical CXC homodimer. Native crystal structures (e.g., PDB ID: 1QG7) further validate the monomeric form in solution. The C-terminus exhibits flexibility, particularly beyond residue 65, which accommodates isoform-specific extensions in SDF-1β (adding residues 69–72: RFKM), allowing similar core folds despite sequence differences. Interactions with glycosaminoglycans like are mediated by basic residues on the protein surface, including Arg20, Lys24, His25, Lys27, and Arg41, which form electrostatic and hydrogen bonds with groups on heparin disaccharides. These binding sites—one at the dimer interface and another near the N-loop and α-helix—promote localized concentration and on surfaces, thereby modulating SDF-1 and presentation to receptors. Structural models from (PDB ID: 2NWG) and NMR highlight how these interactions sequester SDF-1 in the , regulating its gradient formation.

Expression and regulation

Tissue distribution

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, exhibits a broad yet patterned expression across human tissues, with notably high levels in the bone marrow stroma, liver, spleen, heart, brain, and kidneys. In the bone marrow, SDF-1 is predominantly produced by stromal cells, maintaining hematopoietic niches, while in the liver and spleen, expression is prominent in endothelial and fibroblastic compartments. The heart and brain show moderate to high SDF-1 presence in perivascular regions, and the kidneys display expression along glomerular and tubular structures. These patterns have been established through RNA sequencing and protein profiling, revealing CXCL12's role in tissue homeostasis. During embryonic development, SDF-1 expression peaks in specific sites such as the heart, gut, and limbs, supporting organogenesis and cell migration. In the developing heart and vascular system, SDF-1 is dynamically expressed in mesenchymal and endothelial layers; in the gut, it localizes to mesenchyme guiding neural crest migration; and in limbs, it appears in connective tissue patterns. Postnatally, expression levels generally decline except in the bone marrow, where it remains elevated to sustain adult hematopoiesis. At the cellular level, SDF-1 is primarily secreted by fibroblasts, endothelial cells, neurons, and osteoblasts, contributing to its localized distribution. Stromal fibroblasts in various organs serve as a major source, while endothelial cells line vascular structures, and osteoblasts in provide niche support; neuronal expression is evident in the . The Human Protein Atlas immunohistochemistry data further confirm vascular and perivascular staining in multiple tissues, highlighting SDF-1's association with supportive microenvironments. Expression patterns are commonly detected using quantitative PCR (qPCR) for mRNA levels and immunohistochemistry for protein localization, enabling precise mapping across tissues and developmental stages. The predominant circulating isoform in plasma is SDF-1α, whereas SDF-1β predominates in tissue-bound contexts.

Factors regulating expression

The expression of stromal cell-derived factor 1 (SDF-1), also known as CXCL12, is tightly regulated by environmental cues such as hypoxia, which plays a critical role in physiological and pathological processes. Under hypoxic conditions, SDF-1 expression is induced through the stabilization and activation of hypoxia-inducible factor-1α (HIF-1α), a transcription factor that binds directly to hypoxia response elements in the SDF-1 promoter. This binding facilitates transcriptional activation, leading to increased SDF-1 production in various cell types, including endothelial cells and stromal cells. This mechanism is particularly prominent in ischemic tissues, where hypoxia-driven SDF-1 upregulation promotes angiogenesis and progenitor cell recruitment during wound healing. In tumors, the same pathway contributes to neovascularization and metastasis by enhancing the recruitment of endothelial progenitor cells to hypoxic tumor microenvironments. Inflammatory cytokines exert context-dependent effects on SDF-1 expression, often modulating it in response to immune activation. Pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) upregulate SDF-1 production in osteoblasts and other stromal cells, enhancing secretion to support homing and inflammatory cell recruitment. For instance, in primary human osteoblasts and osteoblast-like cell lines, exposure to TNF-α or IL-1β significantly increases SDF-1 mRNA and protein levels, contributing to and repair processes. Transforming growth factor-β (TGF-β) downregulates SDF-1 expression, both at the mRNA level through decreased transcriptional efficiency and at the protein level, in various cell types including stromal cells. In contrast, interferon-γ (IFN-γ) typically downregulates SDF-1 expression, as observed in endothelial cells and other tissues, where it suppresses production to limit excessive immune cell trafficking during . At the transcriptional level, the SDF-1 promoter contains binding sites for key transcription factors, including nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), which integrate signals from inflammatory and stress pathways to fine-tune expression. activation, often triggered by cytokines or , binds to these sites to promote SDF-1 transcription, thereby amplifying responses in inflammatory microenvironments. Similarly, AP-1 sites respond to (MAPK) signaling, facilitating SDF-1 upregulation in response to growth factors and cellular stress. These regulatory elements ensure that SDF-1 expression is dynamically adjusted to support tissue and repair. Post-transcriptional regulation of SDF-1 occurs primarily through microRNAs (miRNAs) that target the 3' (3' UTR) of its mRNA, leading to mRNA degradation or translational repression. For example, miR-23a directly binds to the SDF-1 3' UTR in stromal cells, reducing SDF-1 levels and altering hematopoietic niche function. In addition, miR-886-3p targets the SDF-1 3' UTR in human stromal cells, suppressing expression by up to 85% and thereby altering hematopoietic niche function. These miRNA-mediated mechanisms provide an additional layer of control, particularly in pathological states where dysregulated SDF-1 promotes disease progression.

Receptors and signaling pathways

Interaction with CXCR4

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, primarily interacts with the , a seven-transmembrane G-protein-coupled receptor (GPCR) expressed on various cell types including hematopoietic cells and endothelial cells. This was first identified in 1996 when SDF-1 was demonstrated to bind specifically to CXCR4 (previously termed LESTR or fusin), serving as its primary ligand and blocking HIV-1 entry by competing for the receptor coreceptor site. The binding exhibits high affinity, with dissociation constants (Kd) typically in the range of 1-10 nM, as measured in radioligand binding assays on cells expressing CXCR4. The molecular basis of SDF-1 binding to involves a two-site . The N-terminal domain of SDF-1, particularly residues 1-5 (Lys-Pro-Val-Ser-Leu), inserts into the transmembrane helical bundle of , triggering receptor activation, while the RFFESH motif (residues 12-17) in the N-loop region of SDF-1 facilitates initial docking to the extracellular N-terminal domain of , which is often sulfated at residues to enhance . Structural studies, including NMR and cryo-EM analyses of SDF-1 peptides bound to N-terminal fragments and full complexes, confirm that this engagement positions the SDF-1 core domain to stabilize the receptor's active conformation. Upon binding, SDF-1 activates through Gαi protein coupling, leading to inhibition of adenylate cyclase and reduced cyclic AMP levels, as well as mobilization of intracellular calcium via Cβ activation. This Gαi-dependent signaling also promotes phosphorylation and activation of the ERK/MAPK pathway through downstream effectors like and MEK, contributing to cellular responses such as and . Notably, SDF-1/ complexes often form dimers or higher-order oligomers, which are essential for robust ; monomeric SDF-1 acts as a , while oligomeric forms enhance full GPCR activation and downstream pathway efficiency.

Interaction with CXCR7

Stromal cell-derived factor 1 (SDF-1, also known as CXCL12) binds to CXCR7 (ACKR3), an atypical that functions primarily as a rather than a classical signal transducer. Unlike the canonical receptor , CXCR7 lacks coupling and does not mediate typical responses such as calcium mobilization or upon SDF-1 binding. Instead, it exhibits a higher binding affinity for SDF-1—approximately ten-fold greater than —facilitating rapid capture and . This interaction enables CXCR7 to internalize SDF-1 via , directing it to lysosomal and thereby regulating the local availability of SDF-1 for other receptors like . Upon SDF-1 binding, CXCR7 preferentially recruits β-arrestin, initiating biased signaling pathways independent of Gα subunits. This β-arrestin recruitment occurs through Gβγ subunits and kinase 2 (GRK2), leading to activation of downstream effectors such as (MAPK) pathways, including ERK1/2 phosphorylation. These non-canonical signals promote cellular processes like adhesion and survival, contrasting with the G protein-dependent pathways of , and can be enhanced in contexts of CXCR7-CXCR4 heterodimerization. CXCR7 is highly expressed on tumor lines, activated endothelial s, and certain fetal tissues, where its scavenging activity fine-tunes SDF-1 gradients to modulate CXCR4-mediated responses, such as directed migration and homing. This expression pattern underscores CXCR7's role in shaping microenvironments, particularly in pathological settings like tumorigenesis, without eliciting direct migratory cues.

Interaction with ACKR1

SDF-1 (CXCL12) also interacts with atypical 1 (ACKR1, previously known as DARC or Duffy receptor for ), particularly in its dimeric form. ACKR1, expressed on erythrocytes and endothelial s, functions as a by and internalizing dimeric CXCL12, leading to its clearance without significant signaling through G proteins or β-arrestin pathways. This interaction helps regulate systemic levels and prevent excessive inflammation, with affinity specific to the dimeric conformation that exposes distinct epitopes not accessible in monomers. Structural and functional studies indicate that ACKR1 modulates CXCL12 availability in vascular compartments, influencing immune trafficking and contributing to against infection via erythrocyte expression.

Biological functions

Hematopoiesis and stem cell mobilization

Stromal cell-derived factor 1 (SDF-1, also known as CXCL12) plays a central role in the retention of hematopoietic stem and progenitor cells (HSPCs) within the bone marrow niche. Produced by stromal cells, including CXCL12-abundant reticular (CAR) cells, SDF-1 establishes a concentration gradient that attracts and anchors CD34+ HSPCs expressing the CXCR4 receptor. This interaction activates downstream signaling pathways that promote adhesion through integrins, such as very late antigen-4 (VLA-4), thereby maintaining HSPCs in close proximity to supportive niche components like osteoblasts and endothelial cells. The SDF-1/CXCR4 axis is essential for preserving the quiescent state of HSPCs, ensuring long-term hematopoietic repopulation potential. In adult mice, conditional deletion of leads to a rapid depletion of quiescent long-term repopulating HSPCs (defined as CD34−c-Kit+Sca-1+Lin− cells), while sparing mature progenitors, highlighting its specific role in homeostasis rather than . Nearly all HSPCs are found in direct contact with cells, which are the primary source of SDF-1 in both vascular and endosteal niches, underscoring the chemokine's function in niche organization and HSPC survival. Stem cell mobilization involves the disruption of this SDF-1/CXCR4 retention signal, allowing HSPCs to egress into the peripheral blood. The small molecule AMD3100 (), a reversible , rapidly blocks SDF-1 binding, leading to an approximately 5-fold increase in circulating + cells within hours when combined with (G-CSF). This mechanism was pivotal in the 2008 FDA approval of for mobilizing HSPCs in patients with undergoing autologous transplantation, where it achieved target collections (≥5 × 10^6 + cells/kg) in 72% of cases versus 34% with G-CSF alone. Proteolytic regulation further modulates SDF-1 activity during . (DPP-4, also known as CD26) cleaves the N-terminal dipeptide of SDF-1α, generating an inactive form that reduces its chemotactic potency and promotes HSPC release from the niche. Inhibition of DPP-4, either genetically or pharmacologically, stabilizes intact SDF-1 and enhances mobilization synergy with G-CSF, significantly increasing recruitment of CXCR4+ progenitors in preclinical models.

Immune cell migration

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, acts as a potent chemoattractant for various mature immune cells, including T cells, B cells, monocytes, and neutrophils, guiding their migration through soluble gradients in or immobilized forms in haptotaxis. For instance, SDF-1 promotes the transmigration of + and CD8+ T cells, CD19+ B cells, and CD14+ monocytes across endothelial barriers, a process inhibited by CXCR4-neutralizing antibodies. Similarly, immobilized SDF-1 on substrates facilitates haptotactic movement of B cells within lymphoid tissues, essential for their positioning during immune responses. Neutrophils also respond to SDF-1, particularly in dermal contexts where CXCL12-expressing fibroblasts drive their recruitment to infection sites. The migratory effects of SDF-1 are mediated primarily through its receptor , triggering intracellular signaling that culminates in actin polymerization and directed movement. Upon binding, SDF-1 activates the PI3K/Akt pathway, which promotes cytoskeletal reorganization via assembly, enabling pseudopod formation and essential for . This pathway is critical for the efficient migration of T cells and monocytes, as inhibition of PI3K disrupts SDF-1-induced invasion and dynamics. In homing, SDF-1 supports the trafficking of central memory T cells independently of CCR7, facilitating their entry and retention in secondary lymphoid organs for surveillance. For B cells, SDF-1 contributes to high endothelial venule-mediated entry into s, complementing other like CXCL13. Physiologically, SDF-1 orchestrates immune cell recruitment to sites of and , enhancing host defense by directing leukocytes to damaged tissues. In secondary lymphoid organs, it regulates trafficking and compartmentalization, ensuring coordinated immune responses such as T cell activation and B cell maturation. This homeostatic function extends to rapid mobilization during acute challenges, where SDF-1 gradients guide monocytes and neutrophils to pathogen entry points. Dysregulation of SDF-1 expression leads to elevated levels in chronic inflammation, promoting excessive immune cell infiltration and contributing to autoimmune pathologies. In conditions like , increased SDF-1 in synovial tissues correlates with pathological accumulation of T cells and monocytes, exacerbating joint damage. Similarly, in and systemic lupus erythematosus, heightened SDF-1 drives aberrant and homing, sustaining autoimmune responses. This over-recruitment disrupts immune , highlighting SDF-1's dual role in both protective and detrimental inflammation.

Embryonic development

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, plays a critical role in embryonic development by guiding the migration of various cell types through its interaction with the receptor , ensuring proper organ formation and tissue patterning. In particular, SDF-1 acts as a chemoattractant for primordial germ cells (PGCs), directing their migration from the to the genital ridges during early embryogenesis. PGCs express on their surface, while SDF-1 is produced by the and genital ridges, creating a that facilitates homing and ; disruption of this pathway in SDF-1 or knockout mice results in PGCs failing to colonize the gonads, leading to sterility. Similarly, SDF-1/CXCR4 signaling regulates the migration of cells, including those destined for the peripheral and cardiac structures, by providing directional cues during delamination and invasion of surrounding tissues. In cardiac and vascular development, SDF-1 is essential for the patterning of the ventricular septum and the formation of blood vessels, particularly in the and . SDF-1 mice exhibit ventricular septal defects and impaired vascularization, with thin-walled mesenteric vessels and lack of interconnecting arterial networks, contributing to perinatal lethality observed in both SDF-1- and CXCR4-deficient embryos around embryonic day 18.5. These defects arise from disrupted endothelial and assembly, highlighting SDF-1's paracrine role in organ-specific vascular maturation. Additionally, SDF-1 influences the migration of cardiac cells toward the outflow tract, ensuring proper septation and valve formation. SDF-1/CXCR4 signaling is vital for the tangential migration of progenitors from the rhombic lip to the external granule layer during mid-gestation. In the developing , SDF-1 is expressed in the and , forming a that attracts -expressing granule cells; in knockout mice, granule cells fail to migrate properly, resulting in an abnormally thin external granule layer, ectopic Purkinje cells, and overall . This pathway also coordinates the positioning of other neuronal populations, such as Cajal-Retzius cells, underscoring SDF-1's role in establishing laminar organization in the .

Angiogenesis and wound healing

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, plays a critical role in by recruiting endothelial progenitor cells (EPCs) and mature endothelial cells to sites of through its interaction with the receptors and CXCR7. This recruitment facilitates endothelial cell , , sprouting, and into tube-like structures , thereby promoting the formation of new blood vessels. Additionally, SDF-1 enhances vessel stability by attracting CXCR4-expressing and smooth muscle progenitor cells, which attach to endothelial tubes and support maturation in ischemic tissues. These processes are mediated by downstream signaling involving PI3K/Rac1 pathways that reduce endothelial permeability and activate matrix metalloproteinases for remodeling. In response to hypoxia, SDF-1 expression is rapidly upregulated in ischemic tissues via hypoxia-inducible factor 1 (HIF-1α), peaking within hours and persisting for several days to orchestrate revascularization. This upregulation attracts CXCR4-positive stem and progenitor cells to the injury site, enhancing vascular density and tissue perfusion in models of peripheral vascular disease and myocardial infarction. For instance, in murine myocardial infarction models, intramyocardial delivery of SDF-1 reduces infarct size, increases capillary formation, and improves left ventricular function by promoting stem cell homing and cardioprotection through Akt and ERK signaling. SDF-1 contributes to by chemotactically attracting and EPCs to the injury site, thereby supporting re-epithelialization, deposition, and . Overexpression or sustained delivery of SDF-1, such as through protective conjugates against proteolytic degradation, accelerates closure and regeneration in models. A 2024 study demonstrated that protease-resistant SDF-1 incorporated into hydrogels significantly reduced size in murine excisional wounds by day 3 (p<0.05) compared to controls, with enhanced migration and EPC recruitment leading to improved formation and reduced . In regeneration, SDF-1 supports differentiation by recruiting mesenchymal stromal cells (MSCs) via the axis, amplifying bone morphogenetic protein-2 ()-induced osteogenesis and increasing the osteoblast-to-osteoclast ratio in defect models. In murine femoral defects, combined BMP-2 and SDF-1 treatment resulted in significantly greater volume (2.72 mm³ vs. 1.80 mm³ in controls, p<0.05) and histological healing scores. For muscle regeneration post-injury, SDF-1 pretreatment of adipose-derived stromal cells enhances their migration and myogenic potential, leading to larger myofiber areas (836.9 µm² vs. 583.2 µm² in controls at day 14, p≤0.05) and reduced in rat skeletal muscle models through modulation of M1/M2 balance.

Clinical significance

Role in cancer

Stromal cell-derived factor 1 (SDF-1, also known as ) plays a pivotal role in cancer progression through its interaction with the receptor, forming a axis that promotes tumor , , and establishment at distant sites. This axis is overexpressed in various malignancies, where SDF-1 gradients in target organs guide tumor dissemination, enhancing metastatic potential. In preclinical models, disruption of this signaling pathway has been shown to impair tumor spread, underscoring its mechanistic importance in oncogenesis. The SDF-1/CXCR4 axis is particularly critical in directing to CXCL12-abundant tissues such as , lung, and liver. In , CXCR4 expression on tumor cells facilitates homing to the lungs and , where hypoxic conditions in the upregulate CXCR4 via hypoxia-inducible factor-1α (HIF-1α), promoting and at metastatic sites. Similarly, in , elevated SDF-1 levels in attract CXCR4-positive cancer cells, correlating with osteolytic metastases and poor prognosis. Cancer stem cells also express high levels of CXCR4, enabling their trafficking to these organs and contributing to and resistance. Within the tumor microenvironment, SDF-1 is secreted by cancer-associated fibroblasts (CAFs) and mesenchymal stromal cells (MSCs), fostering a supportive stroma that enhances tumor growth and immune evasion. These stromal cells produce SDF-1 to recruit immunosuppressive populations, including regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs), which infiltrate the tumor and suppress anti-tumor immunity through mechanisms like IL-10 and TGF-β signaling. In and gastric cancers, this recruitment creates an immunologically tolerant niche, allowing tumor progression and . SDF-1 also drives pathological in tumors by synergizing with (VEGF), upregulating its expression and promoting endothelial cell proliferation and vessel formation. In and breast cancers, stromal-derived SDF-1 activates on vascular cells, enhancing that sustains tumor and growth. Recent reviews highlight isoform-specific contributions, with the more stable SDF-1β isoform particularly implicated in advanced tumor progression and due to its prolonged signaling. Therapeutic targeting of the SDF-1/CXCR4 axis with antagonists has shown promise in preclinical models for reducing metastasis. For instance, the CXCR4 inhibitor AMD3100 decreases lung and bone metastases in breast cancer xenografts by blocking tumor cell chemotaxis. In prostate cancer models, CTCE-9908 (a CXCR4 peptide antagonist) inhibits bone metastasis and enhances the efficacy of docetaxel when combined. These findings support ongoing development of CXCR4 blockers like balixafortide for clinical use in metastatic cancers.

Neurological diseases

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, exhibits dual roles in neurological diseases, contributing to by promoting immune cell infiltration while also providing through recruitment and neuronal survival signaling. In the (CNS), SDF-1 interacts primarily with its receptor to guide leukocyte migration and neural progenitor cell (NPC) homing, a process that originates from its established functions in embryonic CNS development. In multiple sclerosis (MS), SDF-1 levels are elevated in the cerebrospinal fluid (CSF), where it facilitates T-cell infiltration across the blood-brain barrier, exacerbating neuroinflammation and demyelination. This chemokine gradient promotes the migration of proinflammatory T cells into the CNS parenchyma, contributing to lesion formation and disease progression in experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Conversely, SDF-1 can suppress ongoing inflammation by polarizing T cells toward a regulatory phenotype, increasing anti-inflammatory IL-10 production and reducing demyelination scores in EAE models (from 2.3 ± 0.3 to 0.4 ± 0.3 with SDF-1 therapy). Blockade of CXCR4, the primary SDF-1 receptor, has been proposed as a therapeutic strategy to limit excessive T-cell infiltration and mitigate demyelination, though it may also impair protective remyelination processes. In (AD), SDF-1 demonstrates neuroprotective effects by enhancing in the and protecting neurons from amyloid-β (Aβ)-induced toxicity via activation of AKT/ERK1/2 pathways. Intracerebral administration of SDF-1 recruits mesenchymal stem cells (MSCs) to Aβ-laden regions, reducing plaque deposition and improving memory deficits in transgenic mouse models. However, SDF-1 is also upregulated by Aβ, attracting to plaques and amplifying hyperphosphorylation and synaptic dysfunction, which contribute to cognitive decline. Plasma SDF-1 levels are decreased in early AD, correlating with impaired hematopoietic support for repair and learning deficits in CXCR4-deficient models. SDF-1 plays a protective role in ischemic by upregulating in the penumbra region post-ischemia, where it recruits endothelial progenitor cells (EPCs) from to promote and limit infarct expansion. This homing is mediated by SDF-1/ signaling, which mobilizes -derived cells to the injury site, enhancing neurovascular repair and NPC in the ischemic core. Additionally, SDF-1 attracts natural killer cells across the blood-brain barrier to reduce secondary , further supporting tissue recovery. In (PD), SDF-1 supports the survival of dopaminergic neurons in the through CXCR4-mediated signaling, which activates anti-apoptotic pathways and reduces neuronal loss in toxin-induced models. Elevated SDF-1 expression in damaged nigrostriatal regions guides homing, increasing hydroxylase-positive cells by up to 50% and providing trophic support for . This axis also modulates microglial activation to limit , preserving motor function in PD models. Recent 2024 studies highlight disruptions in SDF-1 gradients as a key factor in neurodegeneration, where abnormal CXCL12//CXCR7 signaling leads to neuronal loss, deficits, and across diseases like , , and . In , CXCL12 redistribution at the blood-brain barrier intensifies demyelination and affects 45-65% of patients with cognitive symptoms, while in and , pathway dysregulation via PI3K/AKT and MAPK cascades links to / pathology and dopaminergic decline, underscoring SDF-1's potential as a therapeutic target for restoring .

HIV infection

Stromal cell-derived factor 1 (SDF-1), also known as CXCL12, was identified in 1996 as the natural ligand for the CXCR4 and as a potent suppressor of -1 infection, marking a pivotal moment in understanding co-receptor usage. This discovery built on earlier observations of suppressor factors from CD8+ T cells and revealed SDF-1's role in blocking T-cell-tropic (X4) -1 strains, contrasting with macrophage-tropic (R5) strains that use CCR5. The identification of SDF-1 as an endogenous antiviral agent helped establish the framework for receptors as critical entry co-receptors. The primary mechanism of SDF-1's antiviral activity involves competitive binding to , which prevents the HIV-1 envelope gp120 from interacting with the receptor and facilitating viral entry into + T cells. SDF-1α, the predominant isoform, induces rapid internalization and downregulation, further inhibiting infection at early stages such as reverse transcription. This inhibition is mediated by SDF-1's non-ELR motif in its CXC structure, which ensures specific high-affinity binding to without the pro-inflammatory or angiogenic effects associated with ELR-containing CXC chemokines like IL-8. Endogenous SDF-1 levels in lymphoid tissues help limit X4-tropic HIV-1 spread, though they are often insufficient to fully prevent disease progression. Among SDF-1 isoforms, SDF-1α exhibits greater potency in inhibiting X4 HIV-1 entry compared to SDF-1β, primarily due to differences in their C-terminal extensions affecting receptor signaling and efficiency. Clinically, lower SDF-1 concentrations correlate with accelerated HIV-1 disease progression, as reduced availability allows earlier utilization by the virus. Genetic polymorphisms, such as the SDF1-3'A variant (rs1801157) in the 3' , increase SDF-1 expression and have been associated with delayed AIDS onset and resistance to X4-tropic strains in studies.

Therapeutic applications

One of the primary therapeutic applications of targeting the SDF-1/CXCR4 axis involves (AMD3100), a small-molecule antagonist approved by the FDA in 2008 for use in combination with (G-CSF) to mobilize hematopoietic stem and progenitor cells (HSPCs) in patients with and prior to autologous stem cell transplantation. This approval was based on phase III trials demonstrating superior HSPC yields compared to G-CSF alone, enabling more effective collection for transplantation. Investigational agents targeting , such as the cyclic peptide antagonist LY2510924, have advanced to for hematologic malignancies including (AML). In a phase I , LY2510924 administered subcutaneously showed dose-dependent receptor blockade and mobilization of + cells, with an acceptable safety profile up to 20 mg/day, and demonstrated preliminary antileukemic activity when combined with like idarubicin and cytarabine in relapsed or AML patients. SDF-1 mimetics and related therapies are under exploration for , particularly in ischemic conditions where enhancing SDF-1 signaling promotes recruitment and survival. Preclinical studies with recombinant SDF-1 have demonstrated neurite outgrowth and neuroregenerative effects in models of neuronal injury, supporting the development of mimetic agents to mimic these protective mechanisms. However, clinical remains limited, with ongoing focusing on DPP-4 inhibitors that indirectly boost endogenous SDF-1 levels for neuroprotective benefits in neurodegenerative diseases. Emerging trials in 2024-2025 highlight the potential of inhibitors like motixafortide in combinations. Motixafortide, a antagonist approved by the FDA in 2023 for HSPC mobilization, is being evaluated in phase II trials such as CheMo4METPANC, where it combines with PD-1 inhibitors (e.g., ) and standard for first-line metastatic pancreatic ductal , showing improved in pilot data. For , SDF-1 approaches, including mRNA-based delivery, are in preclinical to early clinical stages for peripheral artery disease-associated ulcers, where they enhance and accelerate closure by sustaining local SDF-1 expression. In April 2024, the FDA approved mavorixafor (Xolremdi), an oral antagonist, for treating in WHIM syndrome patients aged 12 years and older, addressing the underlying receptor dysfunction. Challenges in developing SDF-1/-targeted therapies include on-target toxicities such as , observed in up to 7% of patients treated with achieving counts exceeding 100,000/mcL, which can lead to hyperleukocytosis and require monitoring. Additionally, optimizing combinations with is key to overcoming resistance; for instance, antagonists like balixafortide sensitize cells to eribulin by disrupting tumor-stroma interactions, while motixafortide enhances efficacy in by reducing immunosuppression, though dose-limiting gastrointestinal effects necessitate careful sequencing.

Biomarker potential

Stromal cell-derived factor 1 (SDF-1, also known as CXCL12) levels are commonly measured in or using (ELISA), providing a non-invasive method for assessing its concentration in various clinical contexts. Similarly, in patients with , higher SDF-1 concentrations measured by correlate with the presence of and increased all-cause mortality, independent of traditional cardiovascular risk factors. The specificity of SDF-1 as a can be enhanced by evaluating isoform ratios, such as those between the predominant α isoform and the more proteolysis-resistant β isoform, which exhibit differential functions in pathological processes like . For instance, SDF-1β has demonstrated anti-fibrotic effects in experimental models of lung injury, suggesting that isoform-specific profiling may distinguish fibrotic progression from other inflammatory states. In WHIM syndrome, a rare driven by gain-of-function mutations in the SDF-1 receptor , dysregulated SDF-1 signaling contributes to and highlights the pathway as a diagnostic indicator. High circulating or tissue SDF-1 levels have prognostic value across several conditions, correlating with adverse outcomes such as disease progression in multiple sclerosis, where elevated levels in active disease phases predict poorer clinical trajectories, and in solid tumors, where meta-analyses confirm associations with reduced overall survival. A 2017 meta-analysis of CXCL12 expression in various cancers, including breast, lung, and colorectal, demonstrated that high SDF-1 levels independently predict worse prognosis, with hazard ratios indicating increased mortality risk. However, limitations include the influence of systemic inflammation on SDF-1 levels, which can elevate concentrations non-specifically in conditions like acute ischemic events or chronic inflammatory states, reducing its utility as a standalone disease-specific marker.

References

  1. [1]
    The chemokines CXCL8 and CXCL12: molecular and functional ...
    Feb 1, 2023 · CXCL12 is primarily a homeostatic chemokine that induces migration and activation of hematopoietic progenitor cells, endothelial cells, and ...
  2. [2]
    The chemokine SDF-1, stromal cell-derived factor 1, attracts early ...
    SDF-1 is the first chemokine shown to act on early-stage B cell precursors. Mice lacking SDF-1 die perinatally and show a severe deficiency in B lymphopoiesis.
  3. [3]
    The CXC chemokine SDF-1 is the ligand for LESTR/fusin ... - Nature
    Aug 29, 1996 · We report here the identification of a human chemokine of the CXC type, stromal cell-derived factor 1 (SDF-1), as the natural ligand for LESTR/fusin.
  4. [4]
    CXCL12 CXC motif chemokine ligand 12 [ (human)] - NCBI
    Aug 19, 2025 · The allosteric integrin activation by SDF1 is a novel target for drug discovery ... In this study HL-60 cells were treated with SDF-1/CXCL12 for 2 ...
  5. [5]
    600835 - CHEMOKINE, CXC MOTIF, LIGAND 12; CXCL12 - OMIM
    They can be classified into 2 subfamilies. In the CC subfamily, which includes beta chemokine, the cysteine residues are adjacent to each other. In the CXC ...
  6. [6]
    Chemokine CXCL12 in neurodegenerative diseases: a S.O.S signal ...
    CXCL12 (also known as pre-B-cell-growth-stimulating factor [PBSF] or stromal cell-derived factor [SDF]-1) belongs to the CXC subfamily [7].
  7. [7]
    CXCL12 and Its Isoforms: Different Roles in Pancreatic Cancer? - PMC
    Jun 2, 2019 · CXCR4 has two alternative isoforms: CXCR4-A and CXCR4-B. The CXCR4-B isoform is more expressed and undergoes a splicing process, while the CXCR4 ...Missing: nomenclature synonyms
  8. [8]
    A Comprehensive Analysis of CXCL12 Isoforms in Breast Cancer1,2
    On the basis of this analysis, we determined that the most common isoform of CXCL12 in breast cancer is α (65%), followed by β (27%) > γ (5%) > δ (2%). We ...
  9. [9]
  10. [10]
    Recombinant Human/Feline CXCL12/SDF-1 beta (aa 19-93)
    Feline CXCL12( beta ) is synthesized as a 93 amino acid (aa) precursor that contains a 21 aa signal sequence and a 72 aa mature region (3).Missing: 68 lengths
  11. [11]
    Distinguishing Specific CXCL12 Isoforms on Their Angiogenesis ...
    In collagen-only hydrogel, CXCL12-α was the most potent isoform in promoting sprouting and permeability, followed by CXCL12-β and CXCL12-γ. Strikingly, addition ...Missing: gamma delta theta phi
  12. [12]
    The unique structural and functional features of CXCL12 - PMC
    CXCL12 has the unique property of existing in six splice variants in humans, each having a specific tissue distribution and in vivo activity. Controlled splice ...Missing: gamma delta epsilon theta phi
  13. [13]
  14. [14]
    Gene: CXCL12 (ENSG00000107562) - Summary - Ensembl
    CXCL12, also known as C-X-C motif chemokine ligand 12, is located on chromosome 10 and has 7 transcripts. It is a protein coding gene.Missing: nomenclature | Show results with:nomenclature
  15. [15]
    Cxcl12 evolution – subfunctionalization of a ligand through altered ...
    Jul 15, 2011 · We found that exchanging asparagine 33 (which is conserved in mammalian Cxcl12) to serine (Cxcl12a N33S in Fig. 2C) abolished Cxcl12a ...
  16. [16]
  17. [17]
    600835 - CHEMOKINE, CXC MOTIF, LIGAND 12; CXCL12 - OMIM
    They can be classified into 2 subfamilies. In the CC subfamily, which includes beta chemokine, the cysteine residues are adjacent to each other. In the CXC ...Missing: intron | Show results with:intron
  18. [18]
    CXCL12 - Stromal cell-derived factor 1 - Homo sapiens (Human)
    Alternative names. C-X-C motif chemokine 12; Intercrine reduced in ... This entry describes 7 isoforms produced by Alternative splicing. P48061-1.Missing: nomenclature | Show results with:nomenclature
  19. [19]
  20. [20]
    C-Terminal Engineering of CXCL12 and CCL5 Chemokines
    The theoretical molecular weight and isoelectric point were determined with the Expasy ProtParam tool (http://web.expasy.org/protparam/). Chemokine ...
  21. [21]
    Article Cryo-EM structure of monomeric CXCL12-bound CXCR4 in ...
    Aug 27, 2024 · The cysteine in the PC motif forms a disulfide bridge between the N terminus and TM7. The two cysteines in the CXC motif form two disulfide ...
  22. [22]
    Structural and Functional Basis of CXCL12 (Stromal Cell-derived ...
    CXCL12 was originally shown to possess affinity for heparin and heparan sulfate by binding to heparin affinity resin (25). It was proposed that positively ...
  23. [23]
    Solution structure and basis for functional activity of stromal cell ...
    The ability of native SDF‐1 to inhibit HIV‐1 replication arises because the virus has adopted CXCR4 (fusin) as a coreceptor for HIV‐1 entry into target cells ( ...
  24. [24]
    1SDF: SOLUTION STRUCTURE OF STROMAL CELL ... - RCSB PDB
    The three-dimensional structure of stromal cell-derived factor-1 (SDF-1) was determined by NMR spectroscopy. SDF-1 is a monomer with a disordered N-terminal ...
  25. [25]
    Crystal structure of chemically synthesized [N33A] stromal cell ...
    The three-dimensional structure of SDF-1α also is essential for understanding the receptor interactions that result in growth factor and chemoattractant ...
  26. [26]
  27. [27]
  28. [28]
    Secreted CXCL12 (SDF-1) Forms Dimers under Physiologic ...
    These studies show that dimers of CXCL12 only form at concentrations greater than amounts measured in cell culture supernatants or serum [15, 16, 19]. However, ...
  29. [29]
  30. [30]
    CXCL12-CXCR4/CXCR7 Axis in Cancer: from Mechanisms to ...
    The most common α subtype is involved in various physiological or pathological processes, such as myoblasts migration during myogenesis and muscle regeneration ...Cxcl12-Cxcr4 Signal Axis · Cxcl12-Cxcr7 Signal Axis · Peptide Cxcr4 Antagonists
  31. [31]
  32. [32]
    Tissue expression of CXCL12 - Summary - The Human Protein Atlas
    General description of the gene and the encoded protein(s) using information from HGNC and Ensembl, as well as predictions made by the Human Protein Atlas ...
  33. [33]
    CXCL12 protein expression summary - The Human Protein Atlas
    7:Adipose tissue - Mixed function 26:Adrenal gland - Steroid metabolism 77:Bone marrow - Cell proliferation 6:Bone marrow - Innate immune response
  34. [34]
    Embryonic expression and function of the chemokine SDF-1 and its ...
    Sep 15, 1999 · During organogenesis, these genes have dynamic and complementary expression patterns particularly in the developing neuronal, cardiac, vascular, ...
  35. [35]
  36. [36]
    Stromal Cell-Derived Factor 1 - an overview | ScienceDirect Topics
    Stromal cell-derived factor-1 (SDF-1) was discovered independently by three different groups and has been known as pre-B-cell growth-stimulating factor/stromal ...
  37. [37]
    Platelet‐derived CXCL12 (SDF‐1α): basic mechanisms and clinical ...
    CXCL12α and CXCL12β are expressed in several tissues, with the highest expression in the liver, pancreas and spleen. CXCL12γ was detectable in adult human heart ...
  38. [38]
    Stromal-Cell-Derived Factor-1 (SDF-1)/CXCL12 as Potential ... - NIH
    Dec 16, 2011 · This review will focus on the role of the SDF-1/CXCR4 system in the pathophysiology of PVD and discuss their potential as therapeutic targets for PVD.
  39. [39]
    Expression of HIF-1α in Injured Arteries Controls SDF-1α–Mediated ...
    Oct 11, 2007 · HIF-1 binds directly to specific binding sites in the SDF-1 promoter in hypoxic conditions thereby inducing SDF-1 expression. HIF-1 is composed ...
  40. [40]
  41. [41]
    Regulation of CXCL12 and CXCR4 expression by human brain ...
    Treatment with TNF-α, IFN-γ, IL-1β and LPS downregulated CXCL12 and CXCR4 expression and CXCL12 ligation induced internalization of CXCR4. The minimal ...
  42. [42]
    An emerging paradigm of CXCL12 involvement in the metastatic ...
    Of those, CXCL12α and CXCL12β are the most well-studied to-date, with the former being expressed in nearly all organs and representing the predominant isoform ...
  43. [43]
    MicroRNA-23a mediates post-transcriptional regulation of CXCL12 ...
    Jun 1, 2014 · We show for the first time that CXCL12-targeting miR23a regulates the functional properties of the hematopoietic niche.Missing: 150 | Show results with:150
  44. [44]
    MiR-886-3p Down Regulates CXCL12 (SDF1) Expression in ... - NIH
    Screening studies showed that when miR-886-3p was transfected into the CXCL12+ stromal cells, the expression of CXCL12 was down-regulated by as much as 85% when ...Missing: hypoxia | Show results with:hypoxia
  45. [45]
    The lymphocyte chemoattractant SDF-1 is a ligand for LESTR/fusin ...
    We recently found that the CXC-chemokine stromal cell-derived factor-1 (SDF-1) is a highly efficacious lymphocyte chemoattractant.
  46. [46]
    The CXCR4 agonist ligand stromal derived factor-1 maintains high ...
    SDF-1 is novel among agonist ligands of G protein-coupled receptors in that it appears to have equal affinity for both the G protein-coupled and uncoupled ...
  47. [47]
    Characterization and Functionality of CXCR4 Chemokine Receptor ...
    Results: [125I]SDF-1a specifically bound to cultured corneal fibroblasts with a KD value of 8.3 ± 1.2 nM. The presence of CXCR4 was confirmed by autoradiography ...
  48. [48]
    Structural Basis of CXCR4 Sulfotyrosine Recognition by the ... - NIH
    (A) The amino acid sequence of SDF12 with the conserved intramolecular disulfide bonds (black lines) and the engineered intermolecular disulfide bonds (red ...
  49. [49]
    Role of the intracellular domains of CXCR4 in SDF-1–mediated ...
    In this study, we explored the role played by the 3 intracellular loops (ICL1-3) and the C terminus domain of CXCR4 in SDF-1–mediated signaling.
  50. [50]
    Polyfunctionality of the CXCR4/CXCL12 axis in health and disease ...
    Mar 14, 2021 · Historically the chemokine receptor CXCR4 and its canonical ligand CXCL12 are associated with the bone marrow niche and hematopoiesis.
  51. [51]
    Single-molecule imaging reveals dimerization/oligomerization of ...
    Dec 4, 2017 · The chemokine SDF-1alpha triggers CXCR4 receptor dimerization and activates the JAK/STAT pathway. FASEB J 13, 1699–1710 (1999). CAS PubMed ...
  52. [52]
    Crosstalk between SDF-1/CXCR4 and SDF-1/CXCR7 in cardiac ...
    Nov 18, 2015 · In 2005, SDF-1 was revealed to bind a second chemokine receptor CXCR7 with an even 10-fold higher affinity compared with CXCR4. CXCR7 was ...
  53. [53]
  54. [54]
    but not G protein-mediated signaling by the “decoy” receptor CXCR7
    Open in Viewer CXCR7 recruits β-arrestin resulting in MAP kinase activation in transiently transfected HEK293 cells. (A) β-arrestin recruitment in live HEK 293 ...
  55. [55]
    CXCR7: a β-arrestin-biased receptor that potentiates cell migration ...
    Nov 23, 2020 · This study demonstrates that SDF-1α-stimulated CXCR7 mediates β-arrestin2 recruitment via different molecular networking from that of CXCR4.
  56. [56]
    CXCR7/CXCR4 Heterodimer Constitutively Recruits β-Arrestin to ...
    CXCR7/CXCR4 co-expression also results in potentiation of CXCL12 (SDF-1)-mediated downstream β-arrestin-dependent cell signaling pathways, including ERK1/2, p38 ...
  57. [57]
    CXCR4 Axis and Their Role in Stem Cell Homing and Mobilization
    The most important retention mechanism involves CXCL12, which is expressed in hematopoietic niches and interacts with its corresponding CXCR4 receptor expressed ...
  58. [58]
  59. [59]
    The Chemokine SDF-1 Is a Chemoattractant for Human CD34 + ...
    Here, we present evidence that hematopoietic progenitor cells migrate in vitro and in vivo towards a gradient of a chemotactic factor produced by stromal cells.Results · Sdf-1 Induces Calcium... · Discussion
  60. [60]
    Mozobil® (Plerixafor, AMD3100), 10 years after its approval by ... - NIH
    Feb 18, 2019 · In December 2008, AMD3100 was formally approved by the US FDA for autologous transplantation in patients with Non-Hodgkin's Lymphoma or multiple myeloma.
  61. [61]
  62. [62]
    CXCL12/CXCR4/CXCR7 Chemokine Axis and Cancer Progression
    Here we review the current concepts regarding the role of CXCL12/CXCR4/CXCR7 axis activation, which regulates the pattern of tumor growth and metastatic spread.
  63. [63]
    CXCL12+ dermal fibroblasts promote neutrophil recruitment and ...
    Feb 23, 2024 · These findings show that CXCL12+ dermal immune acting fibroblast subsets play a critical role in cutaneous neutrophil recruitment and host defense.
  64. [64]
    CXCL12-Induced Monocyte-Endothelial Interactions Promote ...
    CXCL12 stimulated transmigration of CD4+ and CD8+ T cells, CD19+ B cells, and CD14+ monocytes. Transmigration was blocked by CXCR4-neutralizing antibodies.
  65. [65]
    Essential role of immobilized chemokine CXCL12 in the regulation ...
    Feb 13, 2017 · We show that immobilized CXCL12 is essential for the correct positioning of B-lymphocytes during the GC reaction and for the production of high-affinity ...
  66. [66]
    Atypical CXCL12 signaling enhances neutrophil migration by ...
    Nov 22, 2022 · We found that the CXC chemokine CXCL12 enhanced the nuclear pliability of mouse bone marrow–derived neutrophils to sustain their migration in 3D landscapes.
  67. [67]
    Akt Activation, but not Extracellular Signal–Regulated Kinase ...
    Activation of Akt and ERK1/2 after SDF-1α treatment indicates that SDF-1/CXCR4 signaling involves multiple pathways. To determine the functional role of PI3K/ ...
  68. [68]
    Roles of the MEK1/2 and AKT pathways in CXCL12/CXCR4 induced ...
    The invasion assays and the detection of actin polymerization were tested in these cholangiocarcinoma cells treated with CXC chemokine ligand -12 (CXCL12).
  69. [69]
    CXCL12 Mediates CCR7-independent Homing of Central Memory ...
    Apr 19, 2004 · Central memory CD8+ T cells (TCM) confer superior protective immunity against infections compared with other T cell subsets.<|control11|><|separator|>
  70. [70]
    Chemokine Requirements for B Cell Entry to Lymph Nodes and ...
    B cell entry to lymph nodes and Peyer's patches depends on chemokine receptor signaling, but the principal chemokine involved has not been defined.
  71. [71]
    The influence of SDF-1 (CXCL12) gene in health and disease
    Sep 27, 2024 · SDF-1 plays a dominant role in bone and cartilage metabolism. It directs mesenchymal stem cell migration, controls osteogenesis and ...
  72. [72]
    CXCL12 + fibroblastic reticular cells in lymph nodes facilitate ... - JCI
    May 1, 2025 · CXCL12+ fibroblastic reticular cells in lymph nodes facilitate immune tolerance by regulating T cell–mediated alloimmunity. Yuta Yamamura,1 ...
  73. [73]
    The Role of the CXCL12/CXCR4/ACKR3 Axis in Autoimmune ...
    Aug 27, 2019 · The present review discusses the role of the CXCL12/CXCR4/ACKR3 axis in inflammation, focusing on its involvement in several autoimmune diseases ...
  74. [74]
    The glycoprotein fueling autoimmune storms via CXCR4 and CXCR7
    Elevated expression levels of SDF-1 in target tissues often correlate with pathological immune cell infiltration characteristic of conditions such as rheumatoid ...
  75. [75]
    The multiple faces of CXCL12 (SDF‐1α) in the regulation of ...
    May 25, 2010 · As a pleiotropic chemokine, CXCL12 participates in the regulation of tissue homeostasis, immune surveillance, autoimmunity, and cancer.
  76. [76]
    Impaired colonization of the gonads by primordial germ cells in mice ...
    Here, we show that SDF-1 is not required for directed migration through tissues of embryos but instead is essential for the homing of PGCs into the genital ...
  77. [77]
    CXCR4 and CXCL12 signaling regulates the development of ...
    Recent work with chicken embryos has shown that CXCR4-expressing cardiac neural crest cells migrate toward the chemokine CXCL12 (also named SDF-1) produced by ...
  78. [78]
    Impaired B-lymphopoiesis, myelopoiesis, and derailed cerebellar ...
    CXCR4 and SDF-1 have been shown to mediate the chemotaxis of hematopoietic progenitor cells, lymphocytes, and monocytes in vitro (3, 4) and lymphocyte and ...<|control11|><|separator|>
  79. [79]
    The SDF-1–CXCR4 signaling pathway: a molecular hub modulating ...
    The SDF-1-CXCR4 pathway involves SDF-1 recruiting cells to neo-angiogenic niches, and SDF-1 also induces new blood vessel formation.
  80. [80]
    Stromal Cell–Derived Factor-1α/C-X-C Chemokine Receptor Type 4 ...
    Jun 12, 2014 · Stromal cell–derived factor-1α (SDF-1α) is a small cytokine belonging to the chemokine family and has been shown to be a principal regulator of ...<|control11|><|separator|>
  81. [81]
  82. [82]
    Therapeutic strategies utilizing SDF-1α in ischaemic cardiomyopathy
    Mechanistic role of SDF-1α in response to myocardial injury. SDF-1α is increased in response to hypoxia via HIF-1, but is rapidly cleaved and inactivated by ...2. Sdf-1α-Cxcr4 Signalling · 3.1 Preclinical Studies · 3.2. 3 Dpp4 Inhibitors In Hf
  83. [83]
    SDF-1/CXCR4 mediates acute protection of cardiac function through ...
    Enhanced SDF-1 after myocardial ischemia results in migration of stem cells into the injured heart and thus leads to increased vascular density, enhanced tissue ...Sdf-1/cxcr4 Mediates Acute... · Sdf-1 Mediated Acute... · Role Of Stat3 In...
  84. [84]
    Controlled Release of Collagen-Binding SDF-1α Improves Cardiac ...
    May 26, 2016 · The expression of SDF-1α is upregulated after acute myocardial infarction (AMI). SDF-1α can mobilize stem cells homing to the ischemic heart, ...Cbd-Sdf-1α And Nat-Sdf-1α... · Cbd-Sdf-1α Is Retained And... · Cbd-Sdf-1α Reduces The Scar...
  85. [85]
    Dermal fibroblast expression of stromal cell-derived factor-1 (SDF-1 ...
    Both overexpression of SDF-1 in dermal fibroblasts and treatment with rhSDF-1 to the skin equivalent cultures significantly increased the number of keratinocyte ...Missing: EPCs 2023
  86. [86]
    Protection of stromal cell-derived factor-1 SDF-1/CXCL12 against ...
    Aug 1, 2024 · We here present new insights into modulation of SDF-1 activity in vitro and in vivo by a macromolecular compound, chlorite-oxidized oxyamylose (COAM).
  87. [87]
    Continuous Delivery of Stromal Cell-Derived Factor-1 from Alginate ...
    Our study focused on stromal cell-derived factor-1 (SDF-1), a naturally occurring chemokine that is rapidly overexpressed in response to tissue injury, ...
  88. [88]
    Enhancement of BMP-2 Induced Bone Regeneration by SDF-1α ...
    Recent studies showed that the cytokine stromal cell-derived factor 1 alpha (SDF-1α) has potential to improve the bone regenerative effect of low bone ...
  89. [89]
    IL-4 and SDF-1 Increase Adipose Tissue-Derived Stromal Cell ...
    In the current study, we tested whether IL-4 and SDF-1 could improve the ability of ADSCs to support the regeneration of rat skeletal muscles.Missing: osteoblast | Show results with:osteoblast
  90. [90]
    The Role of chemokine receptor CXCR4 in breast cancer metastasis
    The study identified the pivotal role played by the CXCL12-CXCR4 signaling axis in metastasis, particularly breast cancer metastasis to the lung. ... SDF-1 CXCR4 ...
  91. [91]
    Mesenchymal stromal cells as cancer promoters | Oncogene - Nature
    Oct 16, 2024 · Mesenchymal stromal cells (MSCs) are important cellular constituents of tumor stroma that play an active role in tumor development.
  92. [92]
    CXCR4/CXCL12 Activities in the Tumor Microenvironment ... - MDPI
    CXCL12 belongs to the family of CXC chemokines, which are sub-classified based on the presence or absence of the ELR (Glu-Leu-Arg) motif immediately before ...<|separator|>
  93. [93]
    Revisiting the role of cancer-associated fibroblasts in tumor ...
    CXCL12, also recognized as stromal cell-derived factor 1 (SDF-1), promotes tumor proliferation and angiogenesis via the CXCL12/CXCR4 pathway (151). This ...
  94. [94]
    Targeting the chemokine receptor CXCR4 for cancer therapies
    May 1, 2025 · CXCR4 overexpression is usually correlated with poor prognosis and often associated with metastasis, that depends on the CXCL12-mediated ...
  95. [95]
    New insights into the role of stromal cell-derived factor 1 (SDF-1 ...
    Jan 15, 2016 · CXCL12 is a highly effective chemoattractant for lymphocytes and monocytes but not neutrophils. CXCL12 is present in the cerebrospinal fluid ( ...
  96. [96]
    New insights into the role of stromal cell-derived factor 1 (SDF-1 ...
    CXCL12 may induce CNS inflammatory response by leukocyte migration. •. Additionally, CXCL12 may contribute to remyelination and neuroprotection in MS. •.
  97. [97]
    CXCL12 (SDF-1α) suppresses ongoing experimental autoimmune ...
    We have generated a CXCL12-immunoglobulin (Ig) fusion protein that, when administered during ongoing EAE, rapidly suppresses the disease in wild-type but not ...
  98. [98]
    Stromal cell-derived factor 1α decreases β-amyloid deposition in ...
    Jun 12, 2012 · The results of our study showed that SDF-1α treatment decreased the area and the number of Aβ deposits, increased the level of Iba-1, a marker of microglia.
  99. [99]
    Decreased CXCL12 (SDF-1) Plasma Levels in Early Alzheimer's ...
    Our findings indicate a lack of chemotactic activity in early AD and support the view of a deficient regenerative hematopoietic brain support in early AD.
  100. [100]
    Roles of Chemokine CXCL12 and Its Receptors in Ischemic Stroke
    CXCL12 and CXCR4 are constitutively expressed in the brain but are up-regulated in the ischemic penumbra regions following ischemic stroke. CXCL12/CXCR4 play ...
  101. [101]
    association with bone marrow cell homing to injury - PubMed - NIH
    SDF-1 (CXCL12) is upregulated in the ischemic penumbra following stroke: association with bone marrow cell homing to injury. J Neuropathol Exp Neurol. 2004 ...
  102. [102]
    Brain endothelial CXCL12 attracts protective natural killer cells ...
    Jan 11, 2023 · Our data show a role for blood–brain barrier-derived CXCL12 in attracting protective NK cells to ischemic brain lesions and identifies a new ...<|separator|>
  103. [103]
    Bone Marrow-Derived Mesenchymal Stem Cell Therapy as a ... - NIH
    Recent studies have demonstrated that stromal-cell-derived factor-1 (SDF-1α) and its receptor CXCR4 play an important role in homing MSCs to ischemic brain ...Parkinson's Disease Is A... · Fig. 1 · Fig. 2<|separator|>
  104. [104]
    The CXCL12/CXCR4/ACKR3 Response Axis in Chronic ...
    The current review sought to highlight the specific functions of CXCL12 and its receptors in various neurodegenerative disorders, in order to provide new ...
  105. [105]
    The role of CXCL12/CXCR4/CXCR7 axis in cognitive impairment ...
    This review explores the role of this axis in the pathogenesis of CI across these neurodegenerative diseases, synthesizing current evidence and its ...
  106. [106]
    SDF-1/CXCL12: A Chemokine in the Life Cycle of HIV - PMC
    May 8, 2015 · First, we demonstrated that CXCL12/SDF-1 potently prevented the accumulation newly reverse-transcribed HIV proviral DNA from the genomic viral ...
  107. [107]
    HIV and the chemokine system: 10 years later | The EMBO Journal
    The evolutionary choice of HIV‐1 to exploit chemokine receptors as cellular entry gateways has turned their chemokine ligands into endogenous antiviral factors ...
  108. [108]
    HIV Coreceptor Downregulation as Antiviral Principle: SDF-1α ...
    Ligation of CCR5 by the CC chemokines RANTES, MIP-1α or MIP-1β, and of CXCR4 by the CXC chemokine SDF-1α, profoundly inhibits the replication of HIV strain.
  109. [109]
    SDF-1/CXCL12: A Chemokine in the Life Cycle of HIV - Frontiers
    ... SDF-1 was required for both activation of CXCR4 and inhibition of T-tropic HIV-1 species. This experiment suggested that CXCL12/SDF-1 could inhibit HIV ...<|control11|><|separator|>
  110. [110]
    Enhanced Inhibition of Human Immunodeficiency Virus Type 1 by ...
    Met-SDF-1β is a more potent inhibitor of HIV-1 than wild-type SDF-1β. SDF-1α (and SDF-1β) has been shown to block T-tropic HIV-1 infection (2, 5, 9, 32, 44), ...
  111. [111]
    Plasma Stromal Cell–Derived Factor (SDF)-1 Levels, SDF1-3
    Abstract. Plasma stromal cell–derived factor (SDF)-1 levels, SDF1-3′A polymorphism, and CXCR4+ T lymphocytes in relation to resistance to human immunodefic.
  112. [112]
    Distribution of two HIV-1-resistant polymorphisms (SDF1-3'A and ...
    Recent cohort studies showed that point mutations in these two genes, CCR2-64I and SDF1-3'A, can delay AIDS onset > or = 16 years after seroconversions. The ...
  113. [113]
    Stromal Cell-Derived Factor-1-3′A Polymorphism Favors HIV-1 ...
    Feb 10, 2016 · This polymorphism, named SDF1-3′A or rs1801157, plays an important regulatory role in the production of SDF-1 [9] and has been the subject of ...
  114. [114]
    Sowing the Seeds of a Fruitful Harvest: Hematopoietic Stem Cell ...
    ... AMD3100 (Plerixafor; Mozobil™), which is capable of mobilizing HSC and HPC alone and in combination with G-CSF (93–98) and received FDA approval in 2008.
  115. [115]
    Mobilization of Hematopoietic Stem and Progenitor Cells Using ...
    On the basis of the results of these two phase III randomized placebo controlled trials, plerixafor was FDA-approved, in combination with G-CSF, for HSPC ...
  116. [116]
    A Phase I Trial of LY2510924, a CXCR4 Peptide Antagonist, in ...
    Preclinical data show that CXCR4 antagonists can cause the mobilization of leukocytes and stem cells in vivo (13), a clear indication of target modulation. In ...
  117. [117]
    Initial Report of a Phase I Study of LY2510924, Idarubicin, and ... - NIH
    LY2510924, a second generation CXCR4, showed significant anti-leukemia activity . ... clinical trial data support its efficacy in AML (30). In a phase 1/2 trial ...
  118. [118]
    Recombinant stromal cell‑derived factor‑1 protein promotes neurite ...
    Nov 18, 2020 · In the present study, the effects of recombinant SDF‐1 on neurite outgrowth for nerve regeneration and engineering were evaluated in PC‐12 cells.
  119. [119]
    DPP4 Inhibitors Can Be a Drug of Choice for Type 3 Diabetes
    Jul 27, 2017 · Growing evidence suggests that endogenous peptides such as glucagon-like peptide-1 (GLP-1) and stromal-derived factor-1α (SDF-1α) provide ...Missing: trials | Show results with:trials
  120. [120]
    BioLineRx Announces New Pilot Phase Data from ... - PR Newswire
    May 30, 2025 · The trial is the first large, multi-center, randomized study evaluating motixafortide with a PD-1 inhibitor and first-line PDAC chemotherapies.
  121. [121]
    SDF-1α mRNA therapy in peripheral artery disease - PMC - NIH
    May 2, 2025 · Preclinical studies have demonstrated that exogenous SDF-1 protein administration enhances angiogenesis and accelerates wound healing in PAD ...
  122. [122]
    [PDF] MOZOBIL (plerixafor) Injection, Solution for subcutaneous use
    Hyperleukocytosis: In clinical trials, white blood cell counts of 100,000/mcL or greater were observed, on the day prior to or any day of apheresis, in 7% of ...
  123. [123]
    CXCR4 Antagonism Has Antitumor Activity in Combination with ...
    May 31, 2018 · Major finding: The CXCR4 antagonist balixafortide plus eribulin achieves responses in metastatic breast cancer.
  124. [124]
    BL-8040, a CXCR4 antagonist, in combination with pembrolizumab ...
    May 25, 2020 · These data suggest that combined CXCR4 and PD-1 blockade may expand the benefit of chemotherapy in PDAC and warrants confirmation in subsequent randomized ...