Dysregulated CXCL12 expression in osteoblasts promotes B-lymphocytes preferentially homing to the bone marrow in MRL/lpr mice

Objective: Todetect the abnormal distribution of B-lymphocytes between peripheral and bone marrow (BM) compartments and explore the mechanism of abnormal chemotaxis of B-lymphocytes in lupus subjects. Methods: The proportions of CXC chemokine receptor (CXCR)4+ B cells and CFDA-labeled MRL/lpr-derived B cells were detected by flow cytometry. The levels of CXC chemokine ligand (CXCL)12in peripheral blood (PB)were measured by ELISA. The migrated B cells to osteoblasts (OBs) was measured by transwell migration assay. The relative spatial position of B cells, OBs and CXCL12 was presented by Immunofluorescence assay. Results: Firstly, we found that the percentage of CXCR4+ B cells was lower in PB and higher in the BM from both MRL/lpr mice and patientswith Systemic lupus erythematosus (SLE). Secondly, OBs from MRL/lpr mice produced more CXCL12 than that from C57BL/6 mice. Besides, MRL/lpr-derived OBs demonstrated more potent chemotactic ability toward B-lymphocytes than control OBs by vitro an vivo. Additionally, more B-lymphocytes were found to co-localize with OBs within the periosteal zone of bone in MRL/lpr mice. Lastly, the percentages of CXCR4+B cells were found to be negatively correlated with serum Immunoglobulin (Ig) G concentration, moreover, BM CXCL12 levels were found to be positively correlated with SLE disease activity index Score and negatively correlated with serum Complement3 (C3) concentration. Conclusions: our results indicated that there is a shifted distribution of B-lymphocytes between BM and peripheral compartments in both SLE patients and MRL/lpr mice. Besides, the up-regulated levels of CXCL12 in OBs was indicated to contribute to the enhanced chemotactic migration and anchorage of B-lymphocytes to OBs.

Adipose-derived mesenchymal stem cells suppress fibroblast proliferation of hypertrophic scar through CCL5 and CXCL12

BACKGROUND AND OBJECTIVE

Adipose-derived mesenchymal stem cells (ADSCs) can accelerate wound healing, reduce scar formation, and inhibit hypertrophic scar (HTS). ADSCs can secrete a large amount of CCL5, and CCL5 has been proved to be pro-inflammatory and pro-fibrotic. CXCL12 (SDF-1) is a key chemokine that promotes stem cell migration and survival. Therefore, this study selected normal skin and HTS conditioned medium to simulate different microenvironments, and analyzed the effects of different microenvironments on the expression of CCL5 and CXCL12 in human ADSCs (hADSCs).

MATERIALS AND METHODS

hADSCs with silenced expression of CCL5 and CXCL12 were co-cultured with hypertrophic scar fibroblasts to verify the effects of CCL5 and CXCL12 in hADSCs on the proliferation ability of hypertrophic scar fibroblasts. A mouse model of hypertrophic scar was established to further confirm the effect of CCL5 and CXCL12 in hADSCs on hypertrophic scar formation.

RESULTS

CCL5 level was found to be significantly high in hADSCs cultured in HTS conditioned medium. CXCL12 in HTS group was prominently lowly expressed compared with the normal group. Inhibition of CCL5 in hADSCs enhanced the effects of untreated hADSCs on proliferation of HTS fibroblasts while CXCL12 knockdown exerted the opposite function. Inhibition of CCL5 in hADSCs increased the percentage of HTS fibroblasts in the G0/G1 phase while down-regulation of CXCL12 decreased those. Meanwhile, the down-regulated levels of fibroblast markers including collagen I, collagen III, and α-SMA induced by CCL5 knockdown were significantly up-regulated by CXCL12 inhibition. hADSCs alleviate the HTS of mice through CCL5 and CXCL12.

CONCLUSION

In summary, our results demonstrated that hADSCs efficiently cured HTS by suppressing proliferation of HTS fibroblasts, which may be related to the inhibition of CXCL12 and elevation of CCL5 in hADSCs, suggesting that hADSCs may provide an alternative therapeutic approach for the treatment of HTS.

Increased CXCL12, a potential CSF biomarker for differential diagnosis of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a debilitating and lethal neurodegenerative disorder marked by the gradual deterioration of motor neurons. Diagnosing amyotrophic lateral sclerosis is challenging due to the lack of reliable diagnostic tools, with clinical assessment being the primary criterion. Recently, increased levels of neurofilament light chain in CSF have been considered a useful biomarker in disease, correlating with disease progression but not specific for diagnosis. This study utilized enzyme-linked immunosorbent assay to measure CSF C-X-C motif chemokine ligand 12 levels in healthy controls, amyotrophic lateral sclerosis patients and patients with amyotrophic lateral sclerosis-mimic disorders, assessing its potential as a diagnostic biomarker and comparing it with neurofilament light chain levels. Our results confirmed previous findings, showing increased C-X-C motif chemokine ligand 12 levels in amyotrophic lateral sclerosis patients compared to healthy control (797.07 ± 31.84 pg/mL versus 316.15 ± 16.6 pg/mL; P = 0.000) and increased CSF neurofilament light chain levels in amyotrophic lateral sclerosis (4565.63 ± 263.77 pg/mL) compared to healthy control (847.86 ± 214.37 pg/mL; P = 0.000). Increased C-X-C motif chemokine ligand levels were specific to amyotrophic lateral sclerosis, not seen in amyotrophic lateral sclerosis-mimic conditions like myelopathies (252.20 ± 23.16 pg/mL; P = 0.000), inflammatory polyneuropathies (270.24 ± 32.23 pg/mL; P = 0.000) and other mimic diseases (228.91 ± 29.20 pg/mL; P = 0.000). In contrast, CSF neurofilament light chain levels in amyotrophic lateral sclerosis overlapped with those in myelopathies (2900.11 ± 872.20 pg/mL; P = 0.821) and other mimic diseases (3169.75 ± 1096.65 pg/mL; P = 0.63), but not with inflammatory polyneuropathies (1156.4 ± 356.6 pg/mL; P = 0.000). Receiver operating characteristic curve analysis indicated significant differences between the area under the curve values of C-X-C motif chemokine ligand and neurofilament light chain in their diagnostic capacities. C-X-C motif chemokine ligand could differentiate between amyotrophic lateral sclerosis and myelopathies (area under the curve 0.99 ± 0.005), inflammatory polyneuropathies (area under the curve 0.962 ± 0.027) and other mimic diseases (area under the curve 1.00 ± 0.00), whereas neurofilament light chain was only effective in inflammatory polyneuropathies cases (area under the curve 0.92 ± 0.048), not in myelopathies (area under the curve 0.71 ± 0.09) or other mimic diseases (area under the curve 0.69 ± 0.14). We also evaluated C-X-C motif chemokine ligand levels in plasma [amyotrophic lateral sclerosis (2022 ± 81.8 pg/mL) versus healthy control (1739.43 ± 77.3 pg/mL; P = 0.015)] but found CSF determination (area under the curve 0.97 ± 0.012) to be more accurate than plasma determination (area under the curve 0.65 ± 0.063). In plasma, single molecule array (SIMOA) neurofilament light chain determination [amyotrophic lateral sclerosis (86.00 ± 12.23 pg/mL) versus healthy control (12.69 ± 1.15 pg/mL); P = 0.000] was more accurate than plasma C-X-C motif chemokine ligand 12 (area under the curve 0.98 ± 0.01405). These findings suggest that CSF C-X-C motif chemokine ligand 12 levels can enhance diagnostic specificity in distinguishing amyotrophic lateral sclerosis from amyotrophic lateral sclerosis-mimic disorders, compared to neurofilament light chain. Larger studies are needed to validate these results, but C-X-C motif chemokine ligand 12 determination shows promising diagnostic potential.

Bilayer lipids modulate ligand binding to atypical chemokine receptor 3

Chemokine receptors belong to the large class of G protein-coupled receptors (GPCRs) and are involved in a number of (patho)physiological processes. Previous studies highlighted the importance of membrane lipids for modulating GPCR structure and function. However, the underlying mechanisms of how lipids regulate GPCRs are often poorly understood. Here, we report that anionic lipid bilayers increase the binding affinity of the chemokine CXCL12 for the atypical chemokine receptor 3 (ACKR3) by modulating the CXCL12 binding kinetics. Notably, the anionic bilayer favors CXCL12 over the more positively charged chemokine CXCL11, which we explained by bilayer interactions orienting CXCL12 but not CXCL11 for productive ACKR3 binding. Furthermore, our data suggest a stabilization of active ACKR3 conformations in anionic bilayers. Taken together, the described regulation of chemokine selectivity of ACKR3 by the lipid bilayer proposes an extended version of the classical model of chemokine binding including the lipid environment of the receptor.

Investigational CXCR4 inhibitors in early phase development for the treatment of hematological malignancies

INTRODUCTION

CXCR4/CXCL12 axis regulates cell proliferation, survival, and differentiation, as well as the homing and mobilization of hematopoietic stem cells (HSCs) from bone marrow niches to the peripheral blood. Furthermore, CXCR4 and CXCL12 are key mediators of cross-talk between hematological malignancies and their microenvironments. CXCR4 overexpression drives disease progression, boosts tumor cell survival, and promotes chemoresistance, leading to poor prognosis.

AREAS COVERED

In light of these discoveries, scientific investigations, and clinical trials have underscored the therapeutic promise found in small-molecule antagonists like plerixafor, peptides/peptidomimetics, such as BKT140, monoclonal antibodies like PF-06747143 and ulocuplumab, as well as microRNAs. Their efficacy is evident in reducing tumor burden, inducing apoptosis and sensitizing malignant cells to conventional chemotherapies. This overview delves into the pathogenic role of the CXC4/CXCL12 axis in hematological neoplasms and examines the clinical application of key CXCR4 antagonists.

EXPERT OPINION

The information collectively emphasizes the potential of CXCR4 antagonists as a therapeutic strategy for hematologic malignancies, showcasing advancements in preclinical and clinical studies. As these therapeutic strategies progress through clinical trials, their potential to reshape the prognosis of hematologic malignancies will become increasingly apparent.

Protection of stromal cell-derived factor-1 SDF-1/CXCL12 against proteases yields improved skin wound healing

SDF-1/CXCL12 is a unique chemotactic factor with multiple functions on various types of precursor cells, all carrying the cognate receptor CXCR4. Whereas individual biological functions of SDF-1/CXCL12 have been well documented, practical applications in medicine are insufficiently studied. This is explained by the complex multifunctional biology of SDF-1 with systemic and local effects, critical dependence of SDF-1 activity on aminoterminal proteolytic processing and limited knowledge of applicable modulators of its activity. We here present new insights into modulation of SDF-1 activity in vitro and in vivo by a macromolecular compound, chlorite-oxidized oxyamylose (COAM). COAM prevented the proteolytic inactivation of SDF-1 by two inflammation-associated proteases: matrix metalloproteinase-9/MMP-9 and dipeptidylpeptidase IV/DPPIV/CD26. The inhibition of proteolytic inactivation was functionally measured by receptor-mediated effects, including intracellular calcium mobilization, ERK1/2 phosphorylation, receptor internalization and chemotaxis of CXCR4-positive cells. Protection of SDF-1/CXCL12 against proteolysis was dependent on electrostatic COAM-SDF-1 interactions. By in vivo experiments in mice, we showed that the combination of COAM with SDF-1 delivered through physiological fibrin hydrogel had beneficial effect for the healing of skin wounds. Collectively, we show that COAM protects SDF-1 from proteolytic inactivation, maintaining SDF-1 biological activities. Thus, protection from proteolysis by COAM represents a therapeutic strategy to prolong SDF-1 bioavailability for wound healing applications.

ACKR3 Antagonism Enhances the Repair of Demyelinated Lesions Through Both Immunomodulatory and Remyelinating Effects

Addressing inflammation, demyelination, and associated neurodegeneration in inflammatory demyelinating diseases like multiple sclerosis (MS) remains challenging. ACT-1004-1239, a first-in-class and potent ACKR3 antagonist, currently undergoing clinical development, showed promise in preclinical MS models, reducing neuroinflammation and demyelination. However, its effectiveness in treating established disease and impact on remyelination after the occurrence of demyelinated lesions remain unexplored. This study assessed the therapeutic effect of ACT-1004-1239 in two demyelinating disease models. In the proteolipid protein (PLP)-induced experimental autoimmune encephalomyelitis (EAE) model, ACT-1004-1239 administered upon the detection of the first signs of paralysis, resulted in a dose-dependent reduction in EAE disease severity, concomitant with diminished immune cell infiltrates in the CNS and reduced demyelination. Notably, efficacy correlated with elevated plasma concentrations of CXCL11 and CXCL12, two pharmacodynamic biomarkers of ACKR3 antagonism. Combining ACT-1004-1239 with siponimod, an approved immunomodulatory treatment for MS, synergistically reduced EAE severity. In the cuprizone-induced demyelination model, ACT-1004-1239 administered after 5 weeks of cuprizone exposure, significantly accelerated remyelination, already quantifiable one week after cuprizone withdrawal. Additionally, ACT-1004-1239 penetrated the CNS, elevating brain CXCL12 concentrations. These results demonstrate that ACKR3 antagonism significantly reduces the severity of experimental demyelinating diseases, even when treatment is initiated therapeutically, after the occurrence of lesions. It confirms the dual mode of action of ACT-1004-1239, exhibiting both immunomodulatory effects by reducing neuroinflammation and promyelinating effects by accelerating myelin repair. The results further strengthen the rationale for evaluating ACT-1004-1239 in clinical trials for patients with demyelinating diseases.

Tertiary lymphoid structures as a potential prognostic biomarker for combined hepatocellular-cholangiocarcinoma

BACKGROUND

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA), as a rare primary hepatic tumor, is challenging to accurately assess in terms of the clinical outcomes and prognostic risk factors in patients. This study aimed to clarify the function of tertiary lymphoid structure (TLS) status in predicting the outcome of cHCC-CCA and to preliminarily explore the possible mechanism of TLS formation.

METHODS

The TLSs, with different spatial distributions and densities, of 137 cHCC-CCA were quantified, and their association with prognosis was assessed by Cox regression and Kaplan-Meier analyses. We further validated TLS possible efficacy in predicting immunotherapy responsiveness in two cHCC-CCA case reports. TLS composition and its relationship to CXCL12 expression were analysed by fluorescent multiplex immunohistochemistry.

RESULTS

A high intratumoural TLS score was correlated with prolonged survival, whereas a high TLS density in adjacent tissue indicated a worse prognosis in cHCC-CCA. Mature TLSs were related to favorable outcomes and showed more CD8 + T cells infiltrating tumor tissues. We further divided the cHCC-CCA patients into four immune grades by combining the peri-TLS and intra-TLS, and these grades were an independent prognostic factor. In addition, our reported cases suggested a potential value of TLS in predicting immunotherapy response in cHCC-CCA patients. Our findings suggested that CXCL12 expression in cHCC-CCA tissue was significantly correlated with TLS presence.

CONCLUSION

The spatial distribution and density of TLSs revealing the characteristics of the cHCC-CCA immune microenvironment, significantly correlated with prognosis and provided a potential immunotherapy response biomarker for cHCC-CCA.

Cryo-EM structure of monomeric CXCL12-bound CXCR4 in the active state

CXCR4 binding of its endogenous agonist CXCL12 leads to diverse functions, including bone marrow retention of hematopoietic progenitors and cancer metastasis. However, the structure of the CXCL12-bound CXCR4 remains unresolved despite available structures of CXCR4 in complex with antagonists. Here, we present the cryoelectron microscopy (cryo-EM) structure of the CXCL12-CXCR4-Gi complex at an overall resolution of 2.65 Å. CXCL12 forms a 1:1 stoichiometry complex with CXCR4, following the two-site model. The first 8 amino acids of mature CXCL12 are crucial for CXCR4 activation by forming polar interactions with minor sub-pocket residues in the transmembrane binding pocket. The 3.2-Å distance between V3 of CXCL12 and the "toggle switch" W6.48 marks the deepest insertion among all chemokine-receptor pairs, leading to conformational changes of CXCR4 for G protein activation. These results, combined with functional assays and computational analysis, provide the structural basis for CXCR4 activation by CXCL12.

SP1-Driven FOXM1 Upregulation Induces Dopaminergic Neuron Injury in Parkinson's Disease

The aberrant expression of Forkhead box M1 (FOXM1) has been associated with the pathological processes of Parkinson's disease (PD), but the upstream and downstream regulators remain poorly understood. This study sought to examine the underlying mechanism of FOXM1 in dopaminergic neuron injury in PD. Bioinformatics analysis was conducted to pinpoint the differential expression of FOXM1, which was verified in the nigral tissues of rotenone-lesioned mice and dopaminergic neuron MN9D cells. Interactions among SP1, FOXM1, SNAI2, and CXCL12 were analyzed. To evaluate their effects on dopaminergic neuron injury, the lentiviral vector-mediated manipulation of FOXM1, SP1, and CXCL12 was introduced in rotenone-lesioned mice and MN9D cells. SP1, FOXM1, SNAI2, and CXCL12 abundant expression occurred in rotenone-lesioned mice and MN9D cells. Silencing of FOXM1 delayed the rotenone-induced dopaminergic neuron injury in vitro. Mechanistically, SP1 was an upstream transcription factor of FOXM1 and upregulated FOXM1 expression, leading to increased SNAI2 and CXCL12 expression. In vivo, data confirmed that SP1 promoted dopaminergic neuron injury by activating the FOXM1/SNAI2/CXCL12 axis. Our data indicate that SP1 silencing has neuroprotective effects on dopaminergic neurons, which is dependent upon the inactivated FOXM1/SNAI2/CXCL12 axis.

Mechanistic study of the effect of flexible fixation and load-bearing stress environment on fracture healing and shaping

BACKGROUND

The biomechanical environment created by suture-button fixation Latarjet is conducive to the healing and shaping of the transplanted coracoid, but its mechanism remains unclear. The latest research has found that the absence of stem cell chemokine (CXCL12) impeded bone regeneration in Sonic Hedgehog (SHH)-deficient animals. However, whether the biomechanical environment affects SHH and CXCL12 function has not been studied.

METHODS

Rat fracture models were constructed to simulate stress environments under non-load-bearing and load-bearing conditions. The fracture healing and shaping, as well as the expression levels of SHH and CXCL12, were assessed through gross viewing, micro-computed tomography (micro-CT), and histochemical staining.

RESULTS

Under flexible fixation, the relative bone volume (BV/TV) of rats exposed to the load-bearing stress environment was significantly higher than that of rats under a non-load-bearing stress environment (p ≤ 0.05). Adverse bone shaping was not observed in rats subjected to flexible fixation. The levels of SHH and CXCL12 in load-bearing rats exhibited significant elevation (p ≤ 0.05). Under a load-bearing stress environment, no significant difference was observed in the BV/TV between the flexible fixation group and the rigid fixation group (p ≥ 0.05), but there was excessive hyperplasia of the fracture callus in the rigid fixation group. The levels of SHH and CXCL12 in rats subjected to rigid fixation were significantly elevated (p ≤ 0.05).

CONCLUSIONS

Flexible fixation and load-bearing stress environment may contribute to bone healing and shaping by influencing the levels of SHH and CXCL12, suggested that this mechanism may be relevant to the healing and shaping of the transplanted coracoid after suture-button fixation Latarjet.

The complex nature of CXCR4 mutations in WHIM syndrome

Heterozygous autosomal dominant mutations in the CXCR4 gene cause WHIM syndrome, a severe combined immunodeficiency disorder. The mutations primarily affect the C-terminal region of the CXCR4 chemokine receptor, specifically several potential phosphorylation sites critical for agonist (CXCL12)-mediated receptor internalization and desensitization. Mutant receptors have a prolonged residence time on the cell surface, leading to hyperactive signaling that is responsible for some of the symptoms of WHIM syndrome. Recent studies have shown that the situation is more complex than originally thought, as mutant WHIM receptors and CXCR4 exhibit different dynamics at the cell membrane, which also influences their respective cellular functions. This review examines the functional mechanisms of CXCR4 and the impact of WHIM mutations in both physiological and pathological conditions.

Is it possible to treat melanoma by intercepting the CXCR4/CXCL12 pathway?

Melanoma is a particularly aggressive type of skin cancer that can spread to distant organs, resulting in poor patient outcomes. C-X-C motif chemokine ligand 12 (CXCL12) interacts to the C-X-C chemokine receptor type 4 (CXCR4). This connection between CXCR4 and its companion ligand CXCL12 is important in melanoma metastasis and progression, encouraging cell proliferation, invasion, and survival via downstream signaling pathways. Furthermore, CXCR4 is implicated in the interaction between melanoma cells and the tumor microenvironment, which promotes malignant cell migration and immune evasion. Given the importance of the CXCR4/CXCL12 axis in melanoma, addressing this axis has the potential to prevent metastasis and improve patient outcomes. We present an overview of the CXCR4/CXCL12 axis in cancer progression and explain its role in the melanoma microenvironment in this paper. Furthermore, we investigate CXCR4's predictive usefulness as a possible biomarker for monitoring melanoma progression. Finally, we discuss the most recent research and clinical trials on CXCR4 inhibitors, emphasizing their efficacy and limits. We hope to improve the quality of life for melanoma patients by better understanding the role of CXCR4 and investigating novel therapeutic options.

C-X-C motif chemokine ligand 12-C-X-C chemokine receptor type 4 signaling axis in cancer and the development of chemotherapeutic molecules

Chemokines are small, secreted cytokines crucial in the regulation of a variety of cell functions. The binding of chemokine C-X-C motif chemokine ligand 12 (CXCL12) (stromal cell-derived factor 1) to a G-protein-coupled receptor C-X-C chemokine receptor type 4 (CXCR4) triggers downstream signaling pathways with effects on cell survival, proliferation, chemotaxis, migration, and gene expression. Intensive and extensive investigations have provided evidence suggesting that the CXCL12-CXCR4 axis plays a pivotal role in tumor development, survival, angiogenesis, metastasis, as well as in creating tumor microenvironment, thus implying that this axis is a potential target for the development of cancer therapies. The structures of CXCL12 and CXCR4 have been resolved with experimental methods such as X-ray crystallography, NMR, or cryo-EM. Therefore, it is possible to apply structure-based computational approaches to discover, design, and modify therapeutic molecules for cancer treatments. Here, we summarize the current understanding of the roles played by the CXCL12-CXCR4 signaling axis in cellular functions linking to cancer progression and metastasis. This review also provides an introduction to protein structures of CXCL12 and CXCR4 and the application of computer simulation and analysis in understanding CXCR4 activation and antagonist binding. Furthermore, examples of strategies and current progress in CXCL12-CXCR4 axis-targeted development of therapeutic anticancer inhibitors are discussed.

Neutrophils disrupt B-1a cell homeostasis by targeting Siglec-G to exacerbate sepsis

B-1a cells, an innate-like cell population, are crucial for pathogen defense and the regulation of inflammation through their release of natural IgM and IL-10. In sepsis, B-1a cell numbers are decreased in the peritoneal cavity as they robustly migrate to the spleen. Within the spleen, migrating B-1a cells differentiate into plasma cells, leading to alterations in their original phenotype and functionality. We discovered a key player, sialic acid-binding immunoglobulin-like lectin-G (Siglec-G), which is expressed predominantly on B-1a cells and negatively regulates B-1a cell migration to maintain homeostasis. Siglec-G interacts with CXCR4/CXCL12 to modulate B-1a cell migration. Neutrophils aid B-1a cell migration via neutrophil elastase (NE)-mediated Siglec-G cleavage. Human studies revealed increased NE expression in septic patients. We identified an NE cleavage sequence in silico, leading to the discovery of a decoy peptide that protects Siglec-G, preserves peritoneal B-1a cells, reduces inflammation, and enhances sepsis survival. The role of Siglec-G in inhibiting B-1a cell migration to maintain their inherent phenotype and function is compromised by NE in sepsis, offering valuable insights into B-1a cell homeostasis. Employing a small decoy peptide to prevent NE-mediated Siglec-G cleavage has emerged as a promising strategy to sustain peritoneal B-1a cell homeostasis, alleviate inflammation, and ultimately improve outcomes in sepsis patients.

STAT3-induced lncRNA GNAS-AS1 accelerates keloid formation by mediating the miR-196a-5p/CXCL12/STAT3 axis in a feedback loop

Keloids are pathological scar tissue resulting from skin trauma or spontaneous formation, often accompanied by itching and pain. Although GNAS antisense RNA 1 (GNAS-AS1) shows abnormal upregulation in keloids, the underlying molecular mechanism is unclear. The levels of genes and proteins in clinical tissues from patients with keloids and human keloid fibroblasts (HKFs) were measured using quantitative reverse transcription PCR, western blot and enzyme-linked immunosorbent assay. The features of HKFs, including proliferation and migration, were evaluated using cell counting kit 8 and a wound healing assay. The colocalization of GNAS-AS1 and miR-196a-5p in HKFs was measured using fluorescence in situ hybridization. The relationships among GNAS-AS1, miR-196a-5p and C-X-C motif chemokine ligand 12 (CXCL12) in samples from patients with keloids were analysed by Pearson correlation analysis. Gene interactions were validated by chromatin immunoprecipitation and luciferase reporter assays. GNAS-AS1 and CXCL12 expression were upregulated and miR-196a-5p expression was downregulated in clinical tissues from patients with keloids. GNAS-AS1 knockdown inhibited proliferation, migration, and extracellular matrix (ECM) accumulation of HKFs, all of which were reversed by miR-196a-5p downregulation. Signal transducer and activator of transcription 3 (STAT3) induced GNAS-AS1 transcription through GNAS-AS1 promoter interaction, and niclosamide, a STAT3 inhibitor, decreased GNAS-AS1 expression. GNAS-AS1 positively regulated CXCL12 by sponging miR-196-5p. Furthermore, CXCL12 knockdown restrained STAT3 phosphorylation in HKFs. Our findings revealed a feedback loop of STAT3/GNAS-AS1/miR-196a-5p/CXCL12/STAT3 that promoted HKF proliferation, migration and ECM accumulation and affected keloid progression.

In vitro effects and mathematical modelling of CTCE-9908 (a chemokine receptor 4 antagonist) on melanoma cell survival

CTCE-9908, a CXC chemokine receptor 4 (CXCR4) antagonist, prevents CXCR4 phosphorylation and inhibits the interaction with chemokine ligand 12 (CXCL12) and downstream signalling pathways associated with metastasis. This study evaluated the in vitro effects of CTCE-9908 on B16 F10 melanoma cells with the use of mathematical modelling. Crystal violet staining was used to construct a mathematical model of CTCE-9908 B16 F10 (melanoma) and RAW 264.7 (non-cancerous macrophage) cell lines on cell viability to predict the half-maximal inhibitory concentration (IC50). Morphological changes were assessed using transmission electron microscopy. Flow cytometry was used to assess changes in cell cycle distribution, apoptosis via caspase-3, cell survival via extracellular signal-regulated kinase1/2 activation, CXCR4 activation and CXCL12 expression. Mathematical modelling predicted IC50 values from 0 to 100 h. At IC50, similar cytotoxicity between the two cell lines and ultrastructural morphological changes indicative of cell death were observed. At a concentration 10 times lower than IC50, CTCE-9908 induced inhibition of cell survival (p = 0.0133) in B16 F10 cells but did not affect caspase-3 or cell cycle distribution in either cell line. This study predicts CTCE-9908 IC50 values at various time points using mathematical modelling, revealing cytotoxicity in melanoma and non-cancerous cells. CTCE-9908 significantly inhibited melanoma cell survival at a concentration 10 times lower than the IC50 in B16 F10 cells but not RAW 264.7 cells. However, CTCE-9908 did not affect CXCR4 phosphorylation, apoptosis,\ or cell cycle distribution in either cell line.

Evaluating CXCL12 for Effects on Reactive Gene Expression in Primary Astrocytes

Upon injury to the CNS, astrocytes undergo morphological and functional changes commonly referred to as astrocyte reactivity. Notably, these reactive processes include altered expression of factors that control immune processes and neuronal survival, as well as increased expression of the CXCL12 receptor, CXCR7/ACKR3. We now asked whether these events are related in that the astrocytic CXCL12 system modulates immune responses and/or neuronal survival. Short-term exposure of astrocytes cultured from the postnatal rat cortex to CXCL12 prominently increased the expression of serpine1/PAI1 on the mRNA level, but showed either no or only minor effects on the expression of additional reactive genes, selected from previous array studies. CXCL12-induced increases in PAI1 protein levels were only detectable in the additional presence of chemokines/cytokines, suggesting that translation of serpine1 mRNA depends on the cooperation of various factors. As expected, expression of most of the selected genes increased after acute or chronic activation of astrocytes with either LPS or a combination of IL-1β and TNFα. CXCL12 partially attenuated expression of some of the LPS and IL-1β/TNFα-induced genes under acute conditions, in particular those encoding CXCL9, CXCL10, CXCL11, and CCL5. Taken together, these findings argue for the involvement of the astrocyte CXCL12 system in the control of the immune response of the injured CNS, where it may control distinct steps.

Establishment of Early Blood Perfusion Promotes CXCL12 Expression and Recruits Monocytes/Macrophages in Damaged Adipose Tissue in Mice Model

BACKGROUND

Blood perfusion in the recipient site is important for adipose tissue repair after fat grafting. It delivers host-derived macrophages derived from monocytes in bone marrow to initiate inflammatory reactions and regenerative responses. According to the ability of CXCL12, a stromal cell-derived factor, to recruit monocytes/macrophages, we studied its effect on adipose tissue repair and regeneration under ischemic and normal conditions.

METHODS

Each inguinal fat pad was crushed for 30 seconds with a clamp in mice (n = 35). The left inguinal vessels were divided and cut off (ischemic group), while the right inguinal vessels were kept patent (control group). Seven animals were sacrificed at 1, 3, 7, 14, and 30 days after surgery, and macrophages (Mac2 and CD206) and adipocytes (perilipin) were assessed. Levels of inflammatory factors (interleukin (IL)-1β, IL-6, and tumor necrosis factor-α) and CXCL12 were measured by quantitative PCR.

RESULTS

The number of macrophages was higher in the control group than in the ischemic group at day 3 (10.33 ± 2.40 vs. 1.33 ± 0.33, p = 0.021). The percentage of M2 macrophages was higher in the control group than in the ischemic group at day 7 (p<0.05). The levels of inflammatory factors and CXCL12 were higher in the control group than in the ischemic group at the early stage (p = 0.038).

CONCLUSIONS

Established blood perfusion leads to up-regulation of CXCL12 during adipose tissue repair and regeneration, which may increase recruitment of monocytes to damaged adipose tissue. These findings increase understanding of the cellular events involved in fat graft survival after grafting.

NO LEVEL ASSIGNED

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The effect of CXCL12 on survival outcomes of patients with viral hepatitis-associated hepatocellular carcinoma after hepatectomy

Background

The CXCL12-CXCR4/CXCR7 axis is garnering growing attention. But the comprehension of its function in the progression of HCC remains controversial. The purpose of this study was to investigate the effects of CXCL12 and its receptor on the prognosis of patients with viral hepatitis-associated HCC after hepatectomy.

Methods

A total of 86 patients had been enrolled who had undergone hepatectomy for HCC and followed up to July 31, 2019, and their clinicopathological and follow-up data were recorded. Tumor and peritumoral tissues were obtained to detect the expression of CXCL12, CXCR4, and CXCR7 using immunohistochemistry. Real-time polymerase chain reaction was utilized to detect hepatitis B or C virus loads, while survival analysis was performed using the Kaplan-Meier method. Furthermore, the Cox proportional hazards regression model was employed to analyze the factors affecting the prognosis.

Results

The results revealed that the CXCL12, CXCR4, and CXCR7 expression in tumor tissues was lower than in the corresponding non-tumor tissues in 20.93 %, 22.09 %, and 23.26 % of the patients, respectively, and that only CXCL12 was found to be related to the extrahepatic invasion of HCC. The survival analysis and Cox regression showed that only CXCL12 was associated with the postoperative survival of patients with HCC, and that it was an independent prognostic risk factor in the CXCL12-CXCR4/CXCR7 axis. The CXCL12low group represented shorter progression-free survival and lower overall survival rates. However, the subgroup analysis displayed that the survival difference associated with CXCL12 was only manifested in patients with higher expression of CXCR4 or CXCR7 in HCC, as compared to the surrounding tissues.

Conclusions

Our findings suggest that, when assessing the prognostic significance of CXCL12 in HCC, it is essential to consider the expression level of its receptor. Nevertheless, CXCL12 can potentially serve as a promising prognostic marker for HCC.

Tumor cells express and maintain HMGB1 in the reduced isoform to enhance CXCR4-mediated migration

During inflammation and tissue regeneration, the alarmin High Mobility Group Box 1 (HMGB1), in its reduced isoform, enhances the activity of the chemokine CXCL12, forming a heterocomplex that acts via the chemokine receptor CXCR4. Despite the established roles of both HMGB1 and CXCL12 in tumor progression and metastatic spread to distal sites, the role of the CXCL12/HMGB1 heterocomplex in cancer has never been investigated. By employing a newly established mass spectrometry protocol that allows an unambiguous distinction between reduced (red-HMGB1) and oxidized (ox-HMGB1) HMGB1 isoforms in cell lysates, we demonstrate that human epithelial cells derived from breast (MCF-7 and MDA-MB-231) and prostate (PC-3) cancer predominantly express red-HMGB1, while primary CD3+ T lymphocytes from peripheral blood express both HMGB1 isoforms. All these cancer cells release HMGB1 in the extracellular microenvironment together with varying concentrations of thioredoxin and thioredoxin reductase. The CXCL12/HMGB1 heterocomplex enhances, via CXCR4, the directional migration and invasiveness of cancer cells characterized by high metastatic potential that possess a fully active thioredoxin system, contributing to maintain red-HMGB1. On the contrary, cancer cells with low metastatic potential, lack thioredoxin reductase, promptly uptake CXCL12 and fail to respond to the heterocomplex. Our study demonstrates that the responsiveness of cancer cells to the CXCL12/HMGB1 heterocomplex, resulting in enhanced cell migration and invasiveness, depends on the maintenance of HMGB1 in its reduced isoform, and suggests disruption of the heterocomplex as a potential therapeutic target to inhibit invasion and metastatic spread in cancer therapies.

Preventing CXCL12 elevation helps to reduce acute exacerbation of COPD in individuals co-existing type-2 diabetes: A bioinformatics and clinical pharmacology study

AIMS

To investigate the immunology shared mechanisms underlying chronic obstructive pulmonary disease (COPD) and type 2 diabetes mellitus (T2DM) and examine the impact of anti-diabetic drugs on acute exacerbation of COPD (AECOPD).

METHODS

We analyzed GSE76925, GSE76894, GSE37768, and GSE25724 to identify differentially expressed genes. Hub-genes were identified through protein-protein interaction network analysis and evaluated by the receiver operating characteristic curve. CXCL12 emerged as a robust biomarker, and its correlation with lung function and CD8+ T cells were further quantified and validated. The activated signaling pathways were inferred through Gene set enrichment analysis (GSEA). The retrospective clinical analysis was executed to identify the influence of dipeptidyl peptidase-4 inhibitors (DPP-4i) on CXCL12 and evaluate the drug's efficacy in AECOPD.

RESULTS

The significant up-regulation of CXCL12 expression in patients with two diseases were revealed. CXCL12 exhibited a negative correlation with pulmonary function (r = -0.551, p < 0.05). Consistent with analysis in GSE76925 and GSE76894, the positive correlation between the proportion of CD8+ T cells was demonstrated(r=0.469, p<0.05). GSEA identified "cytokines interaction" as an activated signaling pathway, and the clinical study revealed the correlation between CXCL12 and IL-6 (r=0.668, p<0.05). In patients with COPD and T2DM, DDP-4i treatment exhibited significantly higher serum CXCL12, compared to GLP-1RA. Analysis of 187 COPD patients with T2DM indicated that the DPP-4i group had a higher frequency of AECOPD compared to the GLP-1RA group (OR 1.287, 95%CI [1.018-2.136]).

CONCLUSIONS

CXCL12 may represent a therapeutic target for COPD and T2DM. GLP-1RA treatment may be associated with lower CXCL12 levels and a lower risk of AECOPD compared to DPP-4i treatment.

CLINICAL TRIAL REGISTRATION

China Clinical Trial Registration Center（ChiCTR2200055611）.

CXCR4: From Signaling to Clinical Applications in Neuroendocrine Neoplasms

There are several well-described molecular mechanisms that influence cell growth and are related to the development of cancer. Chemokines constitute a fundamental element that is not only involved in local growth but also affects angiogenesis, tumor spread, and metastatic disease. Among them, the C-X-C motif chemokine ligand 12 (CXCL12) and its specific receptor the chemokine C-X-C motif receptor 4 (CXCR4) have been widely studied. The overexpression in cell membranes of CXCR4 has been shown to be associated with the development of different kinds of histological malignancies, such as adenocarcinomas, epidermoid carcinomas, mesenchymal tumors, or neuroendocrine neoplasms (NENs). The molecular synapsis between CXCL12 and CXCR4 leads to the interaction of G proteins and the activation of different intracellular signaling pathways in both gastroenteropancreatic (GEP) and bronchopulmonary (BP) NENs, conferring greater capacity for locoregional aggressiveness, the epithelial-mesenchymal transition (EMT), and the appearance of metastases. Therefore, it has been hypothesized as to how to design tools that target this receptor. The aim of this review is to focus on current knowledge of the relationship between CXCR4 and NENs, with a special emphasis on diagnostic and therapeutic molecular targets.

Migrasomes from adipose derived stem cells enrich CXCL12 to recruit stem cells via CXCR4/RhoA for a positive feedback loop mediating soft tissue regeneration

BACKGROUND

Adipose-derived stem cells (ASCs) represent the most advantageous choice for soft tissue regeneration. Studies proved the recruitment of ASCs post tissue injury was mediated by chemokine CXCL12, but the mechanism by which CXCL12 is generated after tissue injury remains unclear. Migrasomes are newly discovered membrane-bound organelles that could deliver CXCL12 spatially and temporally in vivo. In this study, we sought to investigate whether migrasomes participate ASC-mediated tissue regeneration.

METHODS

Discrepant and asymmetrical soft tissue regeneration mice model were established, in which HE staining, immunofluorescent staining, western blot and qPCR were conducted to confirm the role of CXCL12 and migrasomes in ASC-mediated tissue regeneration. Characterization of ASC-derived migrasomes were carried out by confocal microscopy, scanning electron microscopy, transmission electron microscopy as well as western blot analysis. The function and mechanism of migrasomes were further testified by assisting tissue regeneration with isolated migrasomes in vivo and by in vitro transwell combined with co-culture system.

RESULTS

Here, we show for the first time that migrasomes participate in soft tissue regeneration. ASCs generate migrasomes enriched with CXCL12 to mediate tissue regeneration. Migrasomes from ASCs could promote stem cells migration by activating CXCR4/RhoA signaling in vivo and in vitro. Chemoattracted ASCs facilitate regeneration, as demonstrated by the upregulation of an adipogenesis-associated protein. This positive feed-back-loop creates a favorable microenvironment for soft tissue regeneration. Thus, migrasomes represent a new therapeutic target for ASC-mediated tissue regeneration.

CONCLUSIONS

Our findings reveal a previously unknown function of ASCs in mediating tissue regeneration by generating migrasomes. The ASC-derived migrasomes can restore tissue regeneration by recruiting stem cells, which highlighting the potential application of ASC-derived migrasomes in regenerative medicine.

Targeting the CXCL12/CXCR4 pathway to reduce radiation treatment side effects

High precision, image-guided radiotherapy (RT) has increased the therapeutic ratio, enabling higher tumor and lower normal tissue doses, leading to improved patient outcomes. Nevertheless, some patients remain at risk of developing serious side effects.In many clinical situations, the radiation tolerance of normal tissues close to the target volume limits the dose that can safely be delivered and thus the potential for tumor control and cure. This is particularly so in patients being re-treated for tumor progression or a second primary tumor within a previous irradiated volume, scenarios that are becoming more frequent in clinical practice.Various normal tissue 'radioprotective' drugs with the potential to reduce side effects have been studied previously. Unfortunately, most have failed to impact clinical practice because of lack of therapeutic efficacy, concern about concurrent tumor protection or excessive drug-related toxicity. This review highlights the evidence indicating that targeting the CXCL12/CXCR4 pathway can mitigate acute and late RT-induced injury and reduce treatment side effects in a manner that overcomes these previous translational challenges. Pre-clinical studies involving a broad range of normal tissues commonly affected in clinical practice, including skin, lung, the gastrointestinal tract and brain, have shown that CXCL12 signalling is upregulated by RT and attracts CXCR4-expressing inflammatory cells that exacerbate acute tissue injury and late fibrosis. These studies also provide convincing evidence that inhibition of CXCL12/CXCR4 signalling during or after RT can reduce or prevent RT side effects, warranting further evaluation in clinical studies. Greater dialogue with the pharmaceutical industry is needed to prioritize the development and availability of CXCL12/CXCR4 inhibitors for future RT studies.