Genetic haute couture to block HIV-1 at front doors.

The chemokine receptors CCR5 and CXCR4 are "front doors" for HIV-1 infection in host cells, and their targeting represents a potential solution for a cure. Dudek et al.1 now propose a new gene editing strategy to simultaneously block CCR5- and CXCR4-mediated HIV-1 entry in autologous hematopoietic stem and progenitor cells (HSPCs).

A simultaneous knockout knockin genome editing strategy in HSPCs potently inhibits CCR5- and CXCR4-tropic HIV-1 infection.

Allogeneic hematopoietic stem and progenitor cell transplant (HSCT) of CCR5 null (CCR5Δ32) cells can be curative for HIV-1-infected patients. However, because allogeneic HSCT poses significant risk, CCR5Δ32 matched bone marrow donors are rare, and CCR5Δ32 transplant does not confer resistance to the CXCR4-tropic virus, it is not a viable option for most patients. We describe a targeted Cas9/AAV6-based genome editing strategy for autologous HSCT resulting in both CCR5- and CXCR4-tropic HIV-1 resistance. Edited human hematopoietic stem and progenitor cells (HSPCs) maintain multi-lineage repopulation capacity in vivo, and edited primary human T cells potently inhibit infection by both CCR5-tropic and CXCR4-tropic HIV-1. Modification rates facilitated complete loss of CCR5-tropic replication and up to a 2,000-fold decrease in CXCR4-tropic replication without CXCR4 locus disruption. This multi-factor editing strategy in HSPCs could provide a broad approach for autologous HSCT as a functional cure for both CCR5-tropic and CXCR4-tropic HIV-1 infections.

Crosstalk between purinergic receptor P2Y11 and chemokine receptor CXCR7 is regulated by CXCR4 in human macrophages.

P2Y11 is a G protein-coupled ATP receptor that activates IL-1 receptor (IL-1R) in a cyclic AMP dependent manner. In human macrophages, P2Y11/IL-1R crosstalk with CCL20 as a prime target is controlled by phosphodiesterase 4 (PDE4), which mediates breakdown of cyclic AMP. Here, we used gene expression analysis to identify activation of CXCR4 and CXCR7 as a hallmark of P2Y11 signaling. We found that PDE4 inhibition with rolipram boosts P2Y11/IL-1R-induced upregulation of CXCR7 expression and CCL20 production in an epidermal growth factor receptor dependent manner. Using an astrocytoma cell line, naturally expressing CXCR7 but lacking CXCR4, P2Y11/IL-1R activation effectively induced and CXCR7 agonist TC14012 enhanced CCL20 production even in the absence of PDE4 inhibition. Moreover, CXCR7 depletion by RNA interference suppressed CCL20 production. In macrophages, the simultaneous activation of P2Y11 and CXCR7 by their respective agonists was sufficient to induce CCL20 production with no need of PDE4 inhibition, as CXCR7 activation increased its own and eliminated CXCR4 expression. Finally, analysis of multiple CCL chemokines in the macrophage secretome revealed that CXCR4 inactivation and CXCR7 activation selectively enhanced P2Y11/IL-1R-mediated secretion of CCL20. Altogether, our data establish CXCR7 as an integral component of the P2Y11/IL-1R-initiated signaling cascade and CXCR4-associated PDE4 as a regulatory checkpoint.

CXCL17 is an allosteric inhibitor of CXCR4 through a mechanism of action involving glycosaminoglycans.

CXCL17 is a chemokine principally expressed by mucosal tissues, where it facilitates chemotaxis of monocytes, dendritic cells, and macrophages and has antimicrobial properties. CXCL17 is also implicated in the pathology of inflammatory disorders and progression of several cancers, and its expression is increased during viral infections of the lung. However, the exact role of CXCL17 in health and disease requires further investigation, and there is a need for confirmed molecular targets mediating CXCL17 functional responses. Using a range of bioluminescence resonance energy transfer (BRET)-based assays, here we demonstrated that CXCL17 inhibited CXCR4-mediated signaling and ligand binding. Moreover, CXCL17 interacted with neuropillin-1, a VEGFR2 coreceptor. In addition, we found that CXCL17 only inhibited CXCR4 ligand binding in intact cells and demonstrated that this effect was mimicked by known glycosaminoglycan binders, surfen and protamine sulfate. Disruption of putative GAG binding domains in CXCL17 prevented CXCR4 binding. This indicated that CXCL17 inhibited CXCR4 by a mechanism of action that potentially required the presence of a glycosaminoglycan-containing accessory protein. Together, our results revealed that CXCL17 is an endogenous inhibitor of CXCR4 and represents the next step in our understanding of the function of CXCL17 and regulation of CXCR4 signaling.

Effects of electroacupuncture on repairing neurological damage following ischemic stroke based on miR-381-mediated SDF-1/CXCR4 signaling pathway. / 基于miR-381调控SDF-1/CXCR4信号通路探讨电针对缺血性脑卒中后神经损伤修复的影响.

OBJECTIVES: To investigate the effects of electroacupuncture (EA) on the miR-381, leucine-rich repeat C4 protein (LRRC4), and downstream stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) signaling pathway in rat model of ischemic stroke, and to explore the mechanism by which EA improves neurological damage following ischemic stroke. METHODS: Among 50 SPF male SD rats, 10 rats were randomly selected into a sham surgery group, and the remaining rats were used to establish the middle cerebral artery occlusion (MCAO) model. The 30 successfully modeled rats were randomly divided into a model group, an EA group, and an agonist group, with 10 rats in each group. The rats in the EA group received EA at "Baihui" (GV 20) and "Dazhui" (GV 14), with disperse-dense wave, a frequency of 2 Hz/10 Hz, and a current intensity of 1 mA, 30 min per session, once daily for a total of 14 days. The rats in the agonist group received miR-381 agonist injections into the lateral ventricle, with 10 µL per injection, every 7 days for a total of 2 injections. After intervention, ZeaLonga neurobehavioral deficit score was observed in each group. HE staining was performed to observe the morphological changes in the ischemic brain tissue of rats in each group. ELISA was used to measure the levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and nerve growth factor (NGF) in serum. Western blot was employed to detect the protein expression of LRRC4, SDF-1, CXCR4, and extracellular regulated protein kinase 1 (ERK1) in the ischemic brain tissue. Real-time PCR was utilized to assess the expression of miR-381 and LRRC4, SDF-1, CXCR4, ERK1 mRNA in the ischemic brain tissue. RESULTS: After intervention, the brain tissue showed disordered cell arrangement, reduced quantity, and significant interstitial edema, with numerous vacuoles in the model group. The pathological changes mentioned above were alleviated in the brain tissue of rats in the EA group and the agonist group. Compared with the sham surgery group, the rats in the model group exhibited increased ZeaLonga neurobehavioral deficit scores, elevated levels of serum TNF-α and IL-6 (P<0.01), and decreased serum NGF level (P<0.01)；the protein expression of SDF-1, CXCR4 and ERK1 in ischemic brain tissue was reduced (P<0.01), while LRRC4 protein expression was increased (P<0.01)；the expression of miR-381, as well as SDF-1, CXCR4 and ERK1 mRNA in ischemic brain tissue was decreased (P<0.01), while LRRC4 mRNA expression was increased (P<0.01). Compared with the model group, the rats in the EA group and the agonist group showed decreased ZeaLonga neurobehavioral deficit scores and reduced levels of serum TNF-α and IL-6 (P<0.05, P<0.01), and increased serum NGF levels (P<0.05, P<0.01); the protein expression of SDF-1, CXCR4 and ERK1 in ischemic brain tissue was increased (P<0.01), while LRRC4 protein expression was decreased (P<0.01)；the expression of miR-381, as well as SDF-1, CXCR4 and ERK1 mRNA in ischemic brain tissue was increased (P<0.05, P<0.01), while LRRC4 mRNA expression was decreased (P<0.01). CONCLUSIONS: EA at "Baihui" (GV 20) and "Dazhui" (GV 14) may promote the repair of neurological damage following ischemic stroke by up-regulating miR-381 to selectively inhibit LRRC4 expression, thereby activating the SDF-1/CXCR4 signaling pathway.

How I use genomics and BTK inhibitors in the treatment of Waldenström macroglobulinemia.

ABSTRACT: Mutations in MYD88 (95%-97%) and CXCR4 (30%-40%) are common in Waldenström macroglobulinemia (WM). TP53 is altered in 20% to 30% of patients with WM, particularly those previously treated. Mutated MYD88 activates hematopoietic cell kinase that drives Bruton tyrosine kinase (BTK) prosurvival signaling. Both nonsense and frameshift CXCR4 mutations occur in WM. Nonsense variants show greater resistance to BTK inhibitors. Covalent BTK inhibitors (cBTKi) produce major responses in 70% to 80% of patients with WM. MYD88 and CXCR4 mutation status can affect time to major response, depth of response, and/or progression-free survival (PFS) in patients with WM treated with cBTKi. The cBTKi zanubrutinib shows greater response activity and/or improved PFS in patients with WM with wild-type MYD88, mutated CXCR4, or altered TP53. Risks for adverse events, including atrial fibrillation, bleeding diathesis, and neutropenia can differ based on which BTKi is used in WM. Intolerance is also common with cBTKi, and dose reduction or switchover to another cBTKi can be considered. For patients with acquired resistance to cBTKis, newer options include pirtobrutinib or venetoclax. Combinations of BTKis with chemoimmunotherapy, CXCR4, and BCL2 antagonists are discussed. Algorithms for positioning BTKis in treatment naïve or previously treated patients with WM, based on genomics, disease characteristics, and comorbidities, are presented.

C-X-C chemokine receptor type 4 promotes tubular cell senescence and renal fibrosis through ß-catenin-inhibited fatty acid oxidation.

The prevalence of chronic kidney disease (CKD) is highly increasing. Renal fibrosis is a common pathological feature in various CKD. Previous studies showed tubular cell senescence is highly involved in the pathogenesis of renal fibrosis. However, the inducers of tubular senescence and the underlying mechanisms have not been fully investigated. C-X-C motif chemokine receptor 4 (CXCR4), a G-protein-coupled seven-span transmembrane receptor, increases renal fibrosis and plays an important role in tubular cell injury. Whereas, whether CXCR4 could induce tubular cell senescence and the detailed mechanisms have not studied yet. In this study, we adopted adriamycin nephropathy and 5/6 nephrectomy models, and cultured tubular cell line. Overexpression or knockdown of CXCR4 was obtained by injection of related plasmids. We identified CXCR4 increased in injury tubular cells. CXCR4 was expressed predominantly in renal tubular epithelial cells and co-localized with adipose differentiation-related protein (ADRP) as well as the senescence-related protein P16INK4A . Furthermore, we found overexpression of CXCR4 greatly induced the activation of ß-catenin, while knockdown of CXCR4 inhibited it. We also found that CXCR4 inhibited fatty acid oxidation and triggered lipid deposition in tubular cells. To inhibit ß-catenin by ICG-001, an inhibitor of ß-catenin, could significantly block CXCR4-suppressed fatty acid oxidation. Taken together, our results indicate that CXCR4 is a key mediator in tubular cell senescence and renal fibrosis. CXCR4 promotes tubular cell senescence and renal fibrosis by inducing ß-catenin and inhibiting fatty acid metabolism. Our findings provide a new theory for tubular cell injury in renal fibrosis.

Single-cell RNA-seq reveals MIF-(CD74 + CXCR4) dependent inhibition of macrophages in metastatic papillary thyroid carcinoma.

BACKGROUND: The mechanism promoting papillary thyroid carcinoma (PTC) metastasis remains unclear. We aimed to investigate the potential metastatic mechanisms at a single-cell resolution. METHODS: We performed single-cell RNA-seq (scRNA-seq) profiling of thyroid tumour (TT), adjacent normal thyroid (NT) and lymph node metastasized tumour (LN) from a young female with PTC. Validation of our results was conducted in 31 tumours with metastasis and 30 without metastasis. RESULTS: ScRNA-seq analysis generated data on 38,215 genes and 0.14 billion transcripts from 28,839 cells, classified into 18 clusters, each annotated to represent 10 cell types. PTC cells were found to originate from epithelial cells. Epithelial cells and macrophages emerged as the strongest signal emitters and receivers, respectively. After reclustering epithelial cells and macrophages, our analysis, incorporating gene set variation analysis (GSVA), SCENIC analysis, and pseudotime trajectory analysis, indicated that subcluster 0 of epithelial cells (EP_0) showed a more malignant phenotype, and subclusters 3 and 4 of macrophages (M_3 and M_4) demonstrated heightened activity. Further analysis suggested that EP_0 may suppress the activity of M_3 and M_4 via MIF - (CD74 + CXCR4) in the MIF pathway. After analysing the expression of the 4 genes in the MIF pathway in both the TCGA cohort and our cohort (n = 61), CD74 was identified as significantly overexpressed in PTC tumours particularly those with lymph node metastasis. CONCLUSION: Our study revealed that PTC may facilitate lymph node metastasis by inhibiting macrophages via MIF signalling. It is suggested that malignant PTC cells may suppress the immune activity of macrophages by consistently releasing signals to them via MIF-(CD74 + CXCR4).

CircMETTL14(11)S upregulated METTL14 and induced CXCR4 to aggravate endothelial inflammation and atherosclerosis.

Endothelial inflammatory response can induce a variety of cardiovascular diseases, including atherosclerosis (AS). As a member of the m6A methyltransferase family, methyltransferase like 14 (METTL14) was reported to propel endothelial inflammation and aggravate AS. In this study, qRT-PCR and western blot analyses were performed to detect the RNA and protein levels of genes. To analyze the cyclic structure and localization of circMETTL14(11)S, agarose gel electrophoresis, subcellular fractionation and FISH assays were conducted. The role of circMETTL14(11)S on endothelial inflammation was exposed by monocyte adhesion assay. Luciferase reporter, chromatin immunoprecipitation (ChIP), pull-down and RNA binding protein immunoprecipitation (RIP) assays were conducted to explore the mechanism of circMETTL14(11)S on endothelial inflammation and AS. We found that circMETTL14(11)S (hsa_circ_0125169) expressed highly in TNF-α-induced endothelial inflammation and positively regulated the expression of METTL14 in human umbilical vein endothelial cells (HUVECs). CircMETTL14(11)S facilitated endothelial inflammation of HUVECs by METTL14. Based on the nuclear location, circMETTL14(11)S was found to activate METTL14 transcription via cooperating with SRY-box transcription factor 2 (SOX2). METTL14 accelerated the m6A methylation and stabilization of C-X-C motif chemokine receptor 4 (CXCR4) mRNA. Further, the facilitation of circMETTL14(11)S/METTL14/CXCR4 on TNF-α-induced endothelial inflammation of HUVECs was verified. Collectively, circMETTL14(11)S/METTL14/CXCR4 axis aggravated endothelial inflammation and AS.

Clinical, biological, electrophysiological and therapeutic profile of patients with anti-MAG neuropathy according to MYD88L265P and CXCR4 mutations and underlying haemopathy.

INTRODUCTION: Anti-MAG neuropathies are associated with an IgM monoclonal gammopathy of undetermined significance (MGUS) or with a malignant haemopathy. Our objective was to determine whether the presence of a haemopathy or somatic mutations of MYD88 and CXCR4 genes influences disease presentation and response to rituximab (RTX). METHODS: We included 79 patients (mean age 74 years, disease duration 9.68 years) who had a bone marrow aspiration with morphologic and immunophenotypic analysis. MYD88L265P and CXCR4 mutations were analysed in peripheral B cells. Information collected included: inflammatory neuropathy cause and treatment sensory sum score (ISS), MRC testing, overall neuropathy limitation scale (ONLS), Rash-built Overall Disability Score (RODS), ataxia score, anti-MAG titres, peak IgM dosage, neurofilament light chain levels, motor and sensory amplitudes, motor unit index (MUNIX) and motor unit size index (MUSIX) sum scores. Efficacy of RTX was evaluated at 12 months in 26 patients. RESULTS: Malignant haematological disorders were discovered in 17 patients (22%): 13 Waldenstrom macroglobulinemia, 3 marginal zone lymphoma and one mantle cell lymphoma. MYD88L265P mutation was detected in 29/60 (48%) patients and CXCR4 in 1 single patient. Disease severity, biological and electrophysiological data and response to RTX were comparable in patients with MGUS/lymphoma and patients with/without MYD88L265P mutation. ISS was lower and MUSIX higher in patients improved by RTX. CONCLUSIONS: MYD88L265P mutation and underlying haemopathies are not predictive of a more severe disease. However, in cases of resistant and progressive neuropathy, they provide an opportunity to prescribe newly available drugs such as Bruton tyrosine kinase inhibitors.

G protein­mediated EGFR transactivation is a common mechanism through which the CXCL12 receptors, CXCR4 and CXCR7, control human cancer cell migration.

C­X­C motif chemokine 12 (CXCL12) promotes metastasis of several tumors by affecting cell migration and invasion via its receptors, C­X­C chemokine receptor type (CXCR)4 and CXCR7. Current therapeutic approaches focus on the selective inactivation of either CXCR4 or CXCR7 in patients with cancer. Alternative strategies may emerge from the analysis of downstream events that mediate the migratory effects of CXCL12 in cancer cells. While CXCR4 activates cell signaling through both G proteins and arrestins, CXCR7 is believed to preferentially signal through arrestins. The present study analyzed the CXCL12­dependent chemotaxis of A549, C33A, DLD­1, MDA­MB­231 and PC­3 cells, in which either the activity of G proteins, EGFR or Src kinase was inhibited pharmacologically or the expression of arrestins was inhibited by RNA interference. The results demonstrated that CXCL12­induced migration of A549, C33A, DLD­1, MDA­MB­231 and PC­3 cells was attenuated by the Gαi/o­inhibitor pertussis toxin (PTX), but was unaffected by small interfering RNA­mediated gene silencing of ß­arrestin1/2. In particular, the sensitivity of DLD­1 migration to PTX was unexpected, as it is solely dependent on the non­classical chemokine receptor, CXCR7. Furthermore, chemotactic responses to CXCL12 were additionally prevented by inhibiting EGFR activity via AG1478 and Src kinase activity via Src inhibitor­1. In conclusion, the results of the present study suggest that G protein­ and Src­dependent transactivation of EGFR is a common mechanism through which CXCL12­bound CXCR4 and/or CXCR7 control cancer cell migration and metastasis. These findings highlight EGFR as a potential therapeutic target that interferes with CXCL12­induced cancer expansion.

Cx4Mab-1: A Novel Anti-Mouse CXCR4 Monoclonal Antibody for Flow Cytometry.

The CXC chemokine receptor 4 (CXCR4, CD184) is a member of the G protein-coupled receptor family that is expressed in most leukocytes. Overexpression of CXCR4 is associated with poor prognosis in not only hematopoietic malignancy but also solid tumors. Because CXCR4 is an attractive target for tumor therapy, reliable preclinical murine models using anti-CXCR4 monoclonal antibodies (mAbs) have been warranted. This study established a novel anti-mouse CXCR4 (mCXCR4) mAb using the Cell-Based Immunization and Screening method. Flow cytometric analysis showed that an anti-mCXCR4 mAb, Cx4Mab-1 (rat IgG2a, kappa), recognized mCXCR4-overexpressed Chinese hamster ovary-K1 (CHO/mCXCR4) cells and endogenously mCXCR4-expressing mouse myeloma P3X63Ag8U.1 (P3U1) cells. Furthermore, Cx4Mab-1 did not recognize mCXCR4-knockout P3U1 cells. The dissociation constants of Cx4Mab-1 for CHO/mCXCR4 and P3U1 were determined as 6.4 × 10-9 M and 2.3 × 10-9 M, respectively, indicating that Cx4Mab-1 possesses a high affinity to both endogenous and exogenous mCXCR4-expressing cells. These results indicate that Cx4Mab-1 could be a useful tool for preclinical mouse models.

Autophagy-Related Gene CXCR4 is a Potential Predictor of Prognosis and Immunotherapy Response for Gastric Cancer.

BACKGROUND: Autophagy is involved in the survival, differentiation, and activation of immune cell subsets. In this study, we determined the prognostic value and biological functions of autophagy genes in gastric cancer (GC). METHODS: The RNA sequencing dataset for gastric cancer was obtained. Differences in prognosis and enrichment pathways in non-negative matrix factorization (NMF) subclasses were analyzed. Next, we analyzed CXC chemokine receptor 4 (CXCR4) by differential expression, clinical value, immune effects, tumor mutation burden (TMB) values, somatic variants, and biological functions. RESULTS: NMF identified three subclasses. Among the three subclasses, there were differences in prognosis, immune cell infiltration, immune checkpoint genes, and enrichment pathways. Moreover, CXCR4 level was elevated in most tumors, and high CXCR4 level was related to poor prognosis in GC patients. CXCR4 expression was significantly correlated with B cells, eosinophils, macrophages, and plasma cells. In in vitro experiment, CXCR4 promoted GC cell proliferation. CONCLUSIONS: Our results showed that CXCR4 is a promising biomarker for predicting prognosis and response to immunotherapy in GC.

Biological and mutational analyses of CXCR4-antagonist interactions and design of new antagonistic analogs.

The chemokine receptor CXCR4 has become an attractive therapeutic target for HIV-1 infection, hematopoietic stem cell mobilization, and cancer metastasis. A wide variety of synthetic antagonists of CXCR4 have been developed and studied for a growing list of clinical applications. To compare the biological effects of different antagonists on CXCR4 functions and their common and/or distinctive molecular interactions with the receptor, we conducted head-to-head comparative cell-based biological and mutational analyses of the interactions with CXCR4 of eleven reported antagonists, including HC4319, DV3, DV1, DV1 dimer, V1, vMIP-II, CVX15, LY2510924, IT1t, AMD3100, and AMD11070 that were representative of different structural classes of D-peptides, L-peptide, natural chemokine, cyclic peptides, and small molecules. The results were rationalized by molecular modeling of CXCR4-antagonist interactions from which the common as well as different receptor binding sites of these antagonists were derived, revealing a number of important residues such as W94, D97, H113, D171, D262, and E288, mostly of negative charge. To further examine this finding, we designed and synthesized new antagonistic analogs by adding positively charged residues Arg to a D-peptide template to enhance the postulated charge-charge interactions. The newly designed analogs displayed significantly increased binding to CXCR4, which supports the notion that negatively charged residues of CXCR4 can engage in interactions with moieties of positive charge of the antagonistic ligands. The results from these mutational, modeling and new analog design studies shed new insight into the molecular mechanisms of different types of antagonists in recognizing CXCR4 and guide the development of new therapeutic agents.

Disruption of cholangiocyte-B cell crosstalk by blocking the CXCL12-CXCR4 axis alleviates liver fibrosis.

B cells can promote liver fibrosis, but the mechanism of B cell infiltration and therapy against culprit B cells are lacking. We postulated that the disruption of cholangiocyte-B-cell crosstalk could attenuate liver fibrosis by blocking the CXCL12-CXCR4 axis via a cyclooxygenase-2-independent effect of celecoxib. In wild-type mice subjected to thioacetamide, celecoxib ameliorated lymphocytic infiltration and liver fibrosis. By single-cell RNA sequencing and flow cytometry, CXCR4 was established as a marker for profibrotic and liver-homing phenotype of B cells. Celecoxib reduced liver-homing B cells without suppressing CXCR4. Cholangiocytes expressed CXCL12, attracting B cells to fibrotic areas in human and mouse. The proliferation and CXCL12 expression of cholangiocytes were suppressed by celecoxib. In CXCL12-deficient mice, liver fibrosis was also attenuated with less B-cell infiltration. In the intrahepatic biliary epithelial cell line HIBEpiC, bulk RNA sequencing indicated that both celecoxib and 2,5-dimethyl-celecoxib (an analog of celecoxib that does not show a COX-2-dependent effect) regulated the TGF-ß signaling pathway and cell cycle. Moreover, celecoxib and 2,5-dimethyl-celecoxib decreased the proliferation, and expression of collagen I and CXCL12 in HIBEpiC cells stimulated by TGF-ß or EGF. Taken together, liver fibrosis can be ameliorated by disrupting cholangiocyte-B cell crosstalk by blocking the CXCL12-CXCR4 axis with a COX-2-independent effect of celecoxib.

[Electroacupuncture combined with bone marrow mesenchymal stem cell transplantation promotes repair of thin endometrium by regulating SDF-1/CXCR4 signaling].

OBJECTIVE: It is to explore, based on stromal cell derived factor 1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) signal axis, whether the electroacupuncture (EA) combined with bone marrow mesenchymal stem cells (BMSCs) transplantation can promote thin endometrium regeneration and improve endometrial receptivity, so as to further study its mechanisms underlying improvement of promoting BMSCs homing to repair thin endometrium. METHODS: Thirty matured female SD rats were randomly divided into normal control , model , BMSCs transplantation (BMSCs), BMSCs+AMD3100 (a specific antagonist of CXCR4, BMSCs+AMD3100), BMSCs+EA, and BMSCs+EA+AMD3100 groups, with 5 rats in each group. The thin endometrial model was established by intrauterine injection of 95% ethanol during the period of estrus. Rats of the model group received intravenous injection of PBS solution (tail vein) on day 1, 3 and 7 of modeling and intraperitoneal injection of normal saline once daily for 3 estrous cycles. Rats of the BMSCs group received intravenous injection of BMSCs suspension on day 1,3 and 7 of modeling, and those of the BMSCs+EA group received BMSCs transplantation and EA stimulation. EA (2 Hz/15 Hz, 1 mA) was applied to "Guanyuan" (CV4) and bilateral "Sanyinjiao"(SP9), "Zigong" (EX-CA1) for 15 min, once daily for 3 estrous cycles. Rats of the BMSCs+AMD3100 group received intravenous injection of BMSCs suspension (1×106/mL) and intraperitoneal injection of AMD3100 (5 mg/kg), and those of the BMSCs+EA+AMD3100 group received administration of BMSCs, AMD3100 and EA, with both groups being once daily for 3 estrous cycles. H.E. staining was used to observe histopathological changes of endometrium tissues, and immunohistochemistry was used to detect the expressions of cytokeratin (CK19) and vimentin in endometrium (for evaluating the damage and repair of endometrium). The expression levels of homeobox A10 (HOXA10), leukemia inhibitory factor (LIF), SDF-1 and CXCR4 proteins were detected by Western blot, and those of SDF-1 and CXCR4 mRNAs in the endometrium detected by real-time PCR. RESULTS: In comparison with the normal control group, the number of endometrial glands, the immunoactivity of CK19 and vimentin, the expression leve-ls of HOXA10, LIF and CXCR4 proteins and CXCR4 mRNA were significantly down-regulated (P<0.01), and the expression levels of SDF-1 protein and mRNA significantly up-regulated (P<0.05) in the model group. Compared with the model group, the number of endometrial glands, the immunoactivity of CK19 and vimentin, and the expression levels of HOXA10, LIF, CXCR4 proteins and CXCR4 mRNA in the BMSCs group, and the number of endometrial glands, the immunoactivity of CK19 and vimentin, the expression levels of HOXA10, LIF, CXCR4 proteins and CXCR4 mRNA, and SDF-1 protein and mRNA in the BMSCs+EA group were significantly up-regulated (P<0.05, P<0.01). Compared to the BMSCs group, the number of endometrial glands, and the expression levels of LIF, CXCR4 proteins and CXCR4 mRNA in the BMSCs+EA group were up-regulated (P<0.01, P<0.05)； the number of endometrial glands, the immunoactivity of CK19 and vimentin, the expression levels of HOXA10, LIF, CXCR4 proteins and CXCR4 mRNA in the BMSCs+AMD3100 group were down-regulated (P<0.01). Compared to the BMSCs+EA group, the number of endometrial glands, the immunoactivity of CK19 and vimentin, the expression levels of HOXA10, LIF, CXCR4 proteins and CXCR4 mRNA in the BMSCs+EA+AMD3100 group were down-regulated (P<0.01). Results of H.E. staining showed thin endometrium with absence of epithelial cells, and sparse glands and blood vessels, with smaller glandular cavity in the model group, which was relative milder in BMSCs and BMSCs+EA groups. CONCLUSION: EA can promote the transfer of transplanted BMSCs to the damaged site through SDF-1/CXCR4 signaling related stem cell homing, thereby promoting thin endometrial regeneration, repairing endometrial injury, and improving endometrial tolerance in rats with thin endometrium.

CXCR4-modified CAR-T cells suppresses MDSCs recruitment via STAT3/NF-κB/SDF-1α axis to enhance efficacy against pancreatic cancer.

Claudin18.2 (CLDN18.2)-specific chimeric antigen receptor (CAR-T) cells displayed limited efficacy in CLDN18.2-positive pancreatic ductal adenocarcinoma (PDAC). Strategies are needed to improve the trafficking capacity of CLDN18.2-specific CAR-T cells. PDAC has a unique microenvironment that consists of abundant cancer-associated fibroblasts (CAFs), which could secrete stromal cell-derived factor 1α (SDF-1α), the ligand of CXCR4. Then, we constructed and explored CLDN18.2-targeted CAR-T cells with CXCR4 co-expression in treating immunocompetent mouse models of PDAC. The results indicated that CXCR4 could promote the infiltration of CAR-T cells and enhance their efficacy in vivo. Mechanistically, the activation of signal transducer and activator of transcription 3 (STAT3) signaling was impaired in CXCR4 CAR-T cells, which reduced the release of inflammatory factors, such as tumor necrosis factor-α, IL-6, and IL-17A. Then, the lower release of inflammatory factors suppressed SDF-1α secretion in CAFs via the nuclear factor κB (NF-κB) pathway. Therefore, the decreased secretion of SDF-1α in feedback decreased the migration of myeloid-derived suppressor cells (MDSCs) in tumor sites. Overall, our study demonstrated that CXCR4 CAR-T cells could traffic more into tumor sites and also suppress MDSC migration via the STAT3/NF-κB/SDF-1α axis to obtain better efficacy in treating CLDN18.2-positive pancreatic cancer. Our findings provide a theoretical rationale for CXCR4 CAR-T cell therapy in PDAC.

Placental insufficiency and heavier placentas in sheep after suppressing CXCL12/CXCR4 signaling during implantation†.

During implantation, trophoblast cell invasion and differentiation is predominantly important to achieving proper placental formation and embryonic development. The chemokine, C-X-C motif chemokine ligand 12 (CXCL12) working through its receptor C-X-C motif chemokine receptor 4 (CXCR4) is implicated in implantation and placentation but precise roles of this axis are unclear. Suppressing CXCL12/CXCR4 signaling at the fetal-maternal interface in sheep reduces trophoblast invasion, disrupts uterine remodeling, and diminishes placental vascularization. We hypothesize these negative impacts during implantation will manifest as compromised fetal and placental growth at midgestation. To test, on day 12 postbreeding, osmotic pumps were surgically installed in 30 ewes and delivered intrauterine CXCR4 inhibitor or saline for 7 or 14 days. On day 90, fetal/maternal tissues were collected, measured, weighed, and maternal (caruncle) and fetal (cotyledon) placenta components separated and analyzed. The objectives were to determine if (i) suppressing CXCL12/CXCR4 during implantation results in reduced fetal and placental growth and development and (ii) if varying the amount of time CXCL12/CXCR4 is suppressed impacts fetal/placental development. Fetal weights were similar; however greater placental weight and placentome numbers occurred when CXCL12/CXCR4 was suppressed for 14 days. In caruncles, greater abundance of fibroblast growth factor 2, vascular endothelial growth factor A, vascular endothelial growth factor A receptor 1 (FLT-1), and placental growth factor were observed after suppressing CXCL12/CXCR4. Similar results occurred in cotyledons except less vascular endothelial growth factor in 7 day group and less fibroblast growth factor in 14 day group. Our data underscore the importance of CXCL12/CXCR4 signaling during placentation and provide strong evidence that altering CXCL12-mediated signaling induces enduring placental effects manifesting later in gestation.

Triazolothiadiazine derivative positively modulates CXCR4 signaling and improves diabetic wound healing.

Development of specific therapies that target and accelerate diabetic wound repair is an urgent need to alleviate pain and suffering and the huge socioeconomic burden of this debilitating disease. C-X-C Motif Chemokine Ligand 12 (CXCL12) also know an stromal cell-derived factor 1α (SDF-1α) is a chemokine that binds the CXC chemokine receptor type 4 (CXCR4) and activates downstream signaling resulting in recruitment of hematopoietic cells to locations of tissue injury and promotes tissue repair. In diabetes, low expression of CXCL12 correlates with impaired wound healing. Activation of CXCR4 receptor signaling with agonists or positive allosteric modulators (PAMs) provides a potential for small molecule therapeutic discovery and development. We recently reported high throughput screening and identification of the CXCR4 partial agonist UCUF-728, characterization of in vitro activity and reduced wound closure time in diabetic mice at 100 µM as a proof-of-concept study. We report here, the discovery of a second chemical scaffold demonstrating increased agonist potency and represented by thiadiazine derivative, UCUF-965. UCUF-965 is a potent partial agonist of ß-arrestin recruitment in CXCR4 receptor overexpressing cell line. Furthermore, UCUF-965 potentiates the CXCL12 maximal response in cAMP signaling pathway, activates CXCL12 stimulated migration in lymphoblast cells and modulates the levels of specific microRNA involved in the complex wound repair process, specifically in mouse fibroblasts. Our results indicate that UCUF-965 acts as a PAM agonist of the CXCR4 receptor. Furthermore, UCUF-965 enhanced angiogenesis markers and reduced wound healing time by 36% at 10.0 µM in diabetic mice models compared to untreated control.