Chemokine C-X-C Motif Ligand 12 Research Articles

From Marrow to Bone and Fat: Exploring the Multifaceted Roles of Leptin Receptor Positive Bone Marrow Mesenchymal Stromal Cells.

The bone marrow (BM) stromal cell microenvironment contains non-hematopoietic stromal cells called mesenchymal stromal cells (MSCs). MSCs are plastic adherent, form CFU-Fs, and give rise to osteogenic, adipogenic, chondrogenic progenitors, and most importantly provide HSC niche factor chemokine C-X-C motif ligand 12 (CXCL12) and stem cell factor (SCF). Different authors have defined different markers for mouse MSC identification like PDGFR+Sca-1+ subsets, Nestin+, or LepR+ cells. Of these, the LepR+ cells are the major source of SCF and CXCL12 in the BM microenvironment and play a major role in HSC maintenance and hematopoiesis. LepR+ cells give rise to most of the bones and BM adipocytes, further regulating the microenvironment. In adult BM, LepR+ cells are quiescent but after fracture or irradiation, they proliferate and differentiate into mesenchymal lineage osteogenic, adipogenic and/or chondrogenic cells. They also play a crucial role in the steady-state hematopoiesis process, as well as hematopoietic regeneration and the homing of hematopoietic stem cells (HSCs) after myeloablative injury and/or HSC transplantation. They line the sinusoidal cavities, maintain the trabeculae formation, and provide the space for HSC homing and retention. However, the LepR+ cell subset is heterogeneous; some subsets have higher adipogenic potential, while others express osteollineage-biased genes. Different transcription factors like Early B cell factor 3 (EBF3) or RunX2 help maintain this balance between the self-renewing and committed states, whether osteogenic or adipogenic. The study of LepR+ MSCs holds immense promise for advancing our understanding of HSC biology, tissue regeneration, metabolic disorders, and immune responses. In this review, we will discuss the origin of the BM resident LepR+ cells, different subtypes, and the role of LepR+ cells in maintaining hematopoiesis, osteogenesis, and BM adipogenesis following their multifaceted impact.

Yigong Powder regulates CXCL12/CXCR4 signaling to reduce glutamate release and prevent cognitive decline in mouse model of aging

This study aims to explore the effect of preventive administration of Yigong Powder on the learning and memory abilities of the mouse model of aging induced by D-galactose and decipher the underlying mechanism, so as to provide a basis for the application of Yigong Powder in the prevention and treatment of cognitive decline. Forty KM mice were randomized into control, model, donepezil(1.5 mg·kg~(-1)), and high-dose(7.5 g·kg~(-1)) and low-dose(3.75 g·kg~(-1)) Yigong Powder groups. The mice in other groups except the control group were injected with D-galactose(200 g·kg~(-1)) at the back of the neck for the modeling of aging. At the same time, the mice were administrated with corresponding drugs by gavage for one month. Morris water maze was used to examine the learning and memory abilities of the mice. Hematoxylin-eosin staining was employed to observe the pathological and morphological changes of the hippocampus. The immunofluorescence assay was employed to detect the expression of ionized calcium-binding adapter molecule 1(IBA1), glial fibrillary acidic protein(GFAP), chemokine C-X-C-motif ligand 12(CXCL12), chemokine C-X-C-motif receptor 4(CXCR4) in the hippocampus and observe the positional relationship between IBA1, GFAP, and CXCR4. Western blot was employed to determine the protein levels of extracellular regulated kinase(ERK), p-ERK, and tumor necrosis factor receptor 1(TNFR1). Enzyme-linked immunosorbent assay was employed to measure the levels of glutamate and tumor necrosis factor(TNF-α) in the brain tissue and the level of TNF-α in the serum and spleen. Yigong Powder significantly shortened the escape latency, increased the times crossing platforms, and prolonged the cumulative time in quadrants of the aging mice. It alleviated the nerve cell disarrangement, increased intercellular space, and cell degeneration or death in the hippocampus and reduced the pathology score of the damaged nerve. Moreover, Yigong Powder reduced the positive area of IBA1 and GFAP, reduced the levels of TNF-α in the brain tissue, serum, and spleen, and decreased spleen index. Furthermore, Yigong Powder decreased the average fluorescence intensity of CXCL12 and CXCR4, reduced CXCR4-positive astrocytes and microglia, down-regulated the protein levels of p-ERK/ERK and TNFR1, and lowered the level of glutamate in the brain tissue. This study showed that the preventive administration of Yigong Powder can ameliorate the learning and memory decline of the D-galactose-induced aging mice by regulating the immune function of the spleen and the CXCL12/CXCR4 signaling in the brain to reduce glutamate release. However, the mechanism of Yigong San in preventing and treating dementia via regulating spleen and stomach function remains to be studied.

Aitongping patch could alleviate cancer pain via suppressing microglia activation and modulating the miR-150-5p/CXCL12 signaling.

We aimed to investigate the pharmacological effects and mechanisms of the Aitongping formula for treating cancer pain. We enrolled 60 cancer patients with Numeric Rating Scale above 4 and grouped them randomly as a Control group (N= 30) and a Patch group (N= 30). We also established bone cancer mice models via tumor implantation. And the animal groups were established as a Sham group, a tumor cell implantation (TCI) group, a TCI + Patch group, and a Patch group. After the validation of successful tumor implantation, we identified candidate miRNAs and genes that were dysregulated in TCI mice and compared their expressions between different mice groups. We also observed the effect of Aitongping patch in vitro in mice primary microglia. The time to disease progression and cancer stability were prolonged by Aitongping patch in cancer patients. And the daily morphine dose was lower, and patients' quality of life was improved in the Patch group. Moreover, Aitongping patch alleviated cancer pain and inhibited microglia activation after the successful implantation of bone tumor in TCI mice. We also observed the dysregulation of miR-150-5p and chemokine CXC motif ligand 12 (CXCL12) mRNA in TCI mice. And CXCL12 was found to be targeted by miR-150-5p. Aitongping patch was found to upregulate miR-150-5p and downregulate CXCL12 in vivo and in vitro. Aitongping patch could alleviate cancer pain via suppressing microglia activation, and the downregulation of miR-150-5p, as well as the upregulation of CXCL12 mRNA and protein, induced by tumor implantation or lipopolysaccharide stimulation, was restored by Aitongping treatment.

Exosome-derived miR-372-5p promotes stemness and metastatic ability of CRC cells by inducing macrophage polarization

Colorectal cancer (CRC) is the most common malignancy in the digestive system, and tumor metastasis is the main cause of death in clinical patients with CRC. It has been shown that exosomes promote phenotypic changes in macrophages and tumor metastasis in the CRC tumor microenvironment. In this study, we used miRNA-seq technology to screen out the highly expressed miR-372-5p among the miRNAs differentially expressed in plasma exosomes of clinical CRC patients. It was found that miR-372-5p highly expressed in HCT116 exosomes could be phagocytosed by macrophages and promote their polarization into M2 macrophages by regulating the PTEN/AKT pathway. Meanwhile, co-culture of CRC cells with conditioned medium (CM) of macrophages enhanced the EMT, stemness and metastasis of CRC cells. Mechanistically, CRC cells exosome-derived miR-372-5p induced polarized M2 macrophages to secrete chemokine C-X-C-Motif Ligand 12 (CXCL12), which activated the WNT/β-catenin pathway to promote the EMT, stemness and metastatic ability of CRC cells. In summary, this study elucidated the molecular mechanism of exosomal miR-372-5p promoting metastasis and stemness in CRC, which may provide new therapeutic targets for CRC metastasis and prognosis assessment.

Unveiling clinical significance and tumor immune landscape of CXCL12 in bladder cancer: Insights from multiple omics analysis.

The interplay between chemokine C-X-C motif ligand 12 (CXCL12) and its specific receptors is known to trigger various signaling pathways, contributing to tumor proliferation and metastasis. Consequently, targeting this signaling axis has emerged as a potential strategy in cancer therapy. However, the precise role of CXCL12 in clinical therapy, especially in immunotherapy for bladder cancer (BCa), remains poorly elucidated. We gathered multiple omics data from public databases to unveil the clinical relevance and tumor immune landscape associated with CXCL12 in BCa patients. Univariate and multivariate Cox regression analyses were employed to assess the independent prognostic significance of CXCL12 expression and formulate a nomogram. The expression of CXCL12 in BCa cell lines and clinical tissue samples was validated using enzyme-linked immunosorbent assays (ELISA) and immunohistochemistry (IHC). While transcriptional expression of CXCL12 exhibited a decrease in nearly all tumor tissues, CXCL12 methylation expression was notably increased in BCa tissues. Single-cell RNA analysis highlighted tissue stem cells and endothelial cells as the primary sources expressing CXCL12. Abnormal CXCL12 expression, based on transcriptional and methylation levels, correlated with various clinical characteristics in BCa patients. Functional analysis indicated enrichment of CXCL12 and its co-expression genes in immune regulation and cell adhesion. The immune landscape analysis unveiled a significant association between CXCL12 expression and M2 macrophages (CD163+ cells) in BCa tissues. Notably, CXCL12 expression emerged as a potential predictor of immunotherapy response and chemotherapy drug sensitivity in BCa patients. Taken together, these findings suggest aberrant production of CXCL12 in BCa tissues, potentially influencing the treatment responses of affected individuals.

Loganin prevents CXCL12/CXCR4-regulated neuropathic pain via the NLRP3 inflammasome axis in nerve-injured rats

BackgroundNeuropathic pain has been shown to be modulated by the activation of the chemokine C-X-C motif ligand 12 (CXCL12)/chemokine CXC receptor 4 (CXCR4) dependent nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome. Loganin, an iridoid glycoside, was proven to prevent neuropathic pain, but its underlying mechanisms related to NLRP3 activation are still unknown. PurposeThis study investigated the underlying mechanisms of loganin's effect on chronic constriction injury (CCI)-induced NLRP3 inflammasome activation in the spinal cord. MethodsSprague-Dawley rats were randomly divided into four groups: sham, CCI, sham + loganin, and CCI + loganin. Loganin (5 mg/kg/day) was administered intraperitoneally starting the day after surgery. Paw withdrawal threshold (PWT) and latency (PWL) were assessed before CCI and on days 1, 3, 7 and 14 after CCI. Spinal cords were collected for western blots and immunofluorescence studies. ResultsLoganin prevented CCI-attenuated PWT and PWL, suggesting improved mechanical allodynia and thermal hyperalgesia. The expression of CXCL12, CXCR4, thioredoxin-interacting protein (TXNIP), NLRP3 inflammasome (NLRP3, ASC, and caspase-1), IL-1β, and IL-18 were enhanced on day 7 after CCI, and all were reduced after loganin treatment. Dual immunofluorescence also showed that increased CXCL12, CXCR4, and NLRP3 were colocalized with NeuN (neuronal marker), GFAP (astrocyte marker), and Iba1 (microglial marker) on day 7 in the ipsilateral spinal dorsal horn (SDH). These immunoreactivities were attenuated in loganin-treated rats. Moreover, loganin decreased the assembly of NLRP3/ASC inflammasome after CCI in the ipsilateral SDH. Loganin appears to attenuate CCI-induced neuropathic pain by suppressing CXCL12/CXCR4-mediated NLRP3 inflammasome. ConclusionOur findings suggest that loganin might be a suitable candidate for managing CCI-provoked neuropathic pain.

Inhibition of the C-X-C Motif Chemokine 12 (CXCL12) and Its Receptor CXCR4 Reduces Utero-Placental Expression of the VEGF System and Increases Utero-Placental Autophagy.

The placenta, a unique organ that only develops during pregnancy, is essential for nutrient, oxygen, and waste exchange between offspring and mother. Yet, despite its importance, the placenta remains one of the least understood organs and knowledge of early placental formation is particularly limited. Abnormalities in placental development result in placental dysfunction or insufficiency whereby normal placental physiology is impaired. Placental dysfunction is a frequent source of pregnancy loss in livestock, inflicting serious economic impact to producers. Though the underlying causes of placental dysfunction are not well-characterized, initiation of disease is thought to occur during establishment of functional fetal and placental circulation. A comprehensive understanding of the mechanisms controlling placental growth and vascularization is necessary to improve reproductive success in livestock. We propose chemokine C-X-C motif ligand 12 (CXCL12) signaling through its receptor CXCR4 functions as a chief coordinator of vascularization through direct actions on fetal trophoblast and maternal endometrial and immune cells. To investigate CXCL12–CXCR4 signaling on uteroplacental vascular remodeling at the fetal–maternal interface, we utilized a CXCR4 antagonist (AMD3100). On day 12 post-breeding in sheep, osmotic pumps were surgically installed and delivered either AMD3100 or saline into the uterine lumen ipsilateral to the corpus luteum for 14 days. On day 35 of ovine pregnancy, fetal/placental and endometrial tissues were collected, snap-frozen in liquid nitrogen, and uterine horn cross sections were preserved for immunofluorescent analysis. Suppressing CXCL12–CXCR4 at the fetal–maternal interface during initial placental vascularization resulted in diminished abundance of select angiogenic factors in fetal and maternal placenta on day 35. Compared to control, less vascular endothelial growth factor (VEGF) and VEFG receptor 2 (KDR) were observed in endometrium when CXCL12–CXCR4 was diminished. Less VEGF was also evident in fetal placenta (cotyledons) in ewes receiving AMD3100 infusion compared to control. Suppressing CXCL12–CXCR4 at the fetal–maternal interface also resulted in greater autophagy induction in fetal and maternal placenta compared to control, suggestive of CXCL12–CXCR4 impacting cell survival. CXCL12–CXCR4 signaling may govern placental homeostasis by serving as a critical upstream mediator of vascularization and cell viability, thereby ensuring appropriate placental development.

The immunoregulatory axis (programmed death-1/programmed death ligand-1) on CD4+ T cells in lupus nephritis: association with vitamin D and chemokine C-X-C motif ligand 12.

Lupus nephritis (LN) is one of the most serious complications of systemic lupus erythematosus (SLE). Multiple immunomodulatory mechanisms contribute to the pathogenesis of LN. A deep understanding of the immunopathogenesis of LN is essential to identify optimal molecular targets, as most immunotherapeutic algorithms are still based on unselective drugs. The study aimed to elucidate the possible association of vitamin D deficiency with the programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) axis and inflammatory response in patients with LN, as well as the relationship between the PD-1/PD-L1 axis and chemokine C-X-C motif ligand 12 (CXCL12). Flow cytometry was used to determine the frequencies of CD279 (PD-1) and CD274 (PD-L1) in the peripheral CD3+CD4+ cell population of persons with LN. Furthermore, ELISA was used to detect serum CXCL12 and vitamin D concentrations. A distinct decrease of PD-1 and a significant increase of PD-L1 was demonstrated in patients with LN compared with either SLE patients with no LN or healthy controls. The PD-1/PD-L1 axis was negatively correlated with different disease parameters. Vitamin D deficiency and insufficiency were more prevalent in patients with LN than in controls, being significantly associated with disease activity and inversely associated with the PD-1/PD-L1 expression. Moreover, CXCL12 was negatively correlated with the PD-1/PD-L1 axis and vitamin D concentration. The findings suggest an involvement of the PD-1/PD-L1 axis in lupus nephritis, which might serve as a potential highly selective therapeutic target that is more effective but less toxic. In addition, restoring adequate vitamin D levels in lupus nephritis could be a possible simple measure to control inflammatory immune responses.

MicroRNA-23 inhibits inflammation to alleviate rheumatoid arthritis via regulating CXCL12.

Rheumatoid arthritis (RA) is a common systemic, inflammatory and autoimmune disorder. MicroRNAs (miRs) are strongly associated with the initiation and progression of RA. However, the functions and mechanisms underlying miR-23 in RA are not completely understood. Therefore, the present study aimed to investigate the molecular mechanisms underlying miR-23 in RA. A bioinformatics tool (StarBase) and a wide range of experimental assays, including reverse transcription-quantitative PCR, western blotting, luciferase reporter assays and ELISAs, were performed to investigate the biological role of miR-23 in RA. The results indicated that miR-23 was downregulated and chemokine C-X-C motif ligand 12 (CXCL12) was upregulated in RA samples compared with healthy samples. Furthermore, miR-23 overexpression suppressed inflammation via reducing TNF-α, IL-1β and IL-8 expression levels compared with the NC mimic group. Regarding the underlying mechanism, compared with NC mimic, miR-23 mimic decreased CXCL12 mRNA expression by binding to its 3'-untranslated region. Additionally, CXCL12 overexpression reversed miR-23 mimic-mediated effects on inflammation. NF-κB signaling is associated with inflammation. Therefore, the present study indicated that CXCL12 promoted inflammation by activating NF-κB signaling. In conclusion, miR-23 inhibited inflammation to alleviate RA by regulating CXCL12 via the NF-κB signaling pathway, which may serve as a potential target for the diagnosis and treatment of RA.

Expression and significance of chemokine CXCL12 and receptor CXCR4 in adenomyosis

Objective: To observe the expression, correlation and significance of chemokine (C-X-C motif) ligand 12 (CXCL12) and chemokine (C-X-C motif) receptor 4 (CXCR4) in endometrium and myometrium of adenomyosis. Methods: Totally 38 patients were selected in this study, who underwent hysterectomy for adenomyosis at Beijing Obstetrics and Gynecology Hospital from October 2017 to December 2018 as the adenomyosis group, and, in the same period, selected 31 patients with cervical intraepithelial neoplasia Ⅲ or cervical cancer undergoing hysterectomy served as control group. The expression levels of mRNA and protein for CXCL12, CXCR4 in the endometrium and myometrium of the two groups were detected by immunohistochemistry and real-time PCR. Results: (1) The protein levels of CXCL12 and CXCR4 in endometrium in uterus with adenomyosis (0.229±0.025 and 0.226±0.016) were significantly higher than those in endometrium in uterus without adenomyosis (0.153±0.018 and 0.178±0.026); compared with each other, the differences were statistically significant (all P<0.05). And the expressions of CXCL12 and CXCR4 proteins in uterine myometrium of adenomyosis were 0.222±0.045 and 0.126±0.058, respectively, which were higher than those in the control group (0.091±0.029 and 0.099±0.020); compared with each other, the differences were statistically significant (all P<0.05). (2) The expression levels of CXCL12 and CXCR4 mRNA in endometrium of patients with adenomyosis were 6.31±0.12 and 8.49±0.21, respectively, which were higher than those in the control group (1.23±0.10 and 1.36±0.13); compared with each other, the differences were statistically significant (all P<0.05). Moreover, the expression levels of CXCL12 and CXCR4 mRNA in myometrium of patients with adenomyosis were 9.11±0.12 and 8.45±0.16, respectively, which were higher than those in the control group (1.18±0.08 and 1.46±0.13); compared with each other, the differences were statistically significant (all P<0.05). (3) In endometrium and myometrium of uterus with adenomyosis, CXCL12 and CXCR4 mRNA expression levels were positively associated (r=0.478, 0.542, all P<0.05). Conclusions: The levels of CXCL12 and CXCR4 in the endometrium and myometrium of adenomyosis are increased and positively correlated. The two chemokine may be involved in the development of adenomyosis.

Research advances of microRNA involved in bone cancer pain

At present, since the mechanism of occurrence and development of bone cancer pain (BCP) is sophisticated, it is still perplexing in the clinical practice. MicroRNA (miRNA), which plays a regulatory role at the post-transcriptional level, may be in-volved in the BCP process. Therefore, the search for unique miRNA and biomarkers involved in the occurrence and development of BCP will be helpful for the treatment, clinical detection and diagnosis. In this paper, we reviewed recent researches and described how miRNA regulate osteoclast activation, promoted bone resorption and led to the formation of BCP. We also described how miRNA regu-late different signaling pathways [chemokine C-X-C motif ligand 12 (CXCL12)/chemokine C-X-C motif receptor 4 (CXCR4) signaling pathway, protein kinase A/cAMP-response element binding protein (CREB) signaling pathway, et al] that involved in the formation and development of BCP and how miRNA plays a role in BCP regulation by regulating neuronal plasticity and changing the expression of neuronal ion channels. Subsequently, This review summarizes the occurrence and development mechanism of BCP and provides help for clinical transformation. Key words: MicroRNA; Bone cancer pain; Osteoclast

The clinical usefulness of chemokine C-X-C Motif Ligand 12 as a diagnostic marker for Papillary Thyroid Carcinoma.

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer worldwide. It is essential to develop methods for the accurate diagnosis of PTC to avoid unnecessary surgery. The chemokine C-X-C motif ligand 12 (CXCL12) is associated with various cancers. We aimed to investigate the efficacy of CXCL12 in the diagnosis of PTC in fine-needle aspiration (FNA) specimens. We prospectively collected samples from 58 patients who were scheduled for surgical treatment of PTC from 2013 to 2015. Tissue samples of 31 people with benign thyroid conditions were used as controls. Immunocytochemical and immunohistochemical staining for CXCL12 was performed on FNAs and corresponding tissue specimens. B-type Raf kinase (BRAF) V600E mutant protein expression and gene mutation were also analyzed to compare the clinical usefulness. : The mean age of the patients was 49.1 ± 1.4 years and 88.1% were women. Positive CXCL12 staining was observed in 6.5% of benign and in 98.3% of PTC samples; positive BRAF V600E mutant protein expression was found in 19.4% of benign and 93.1% of PTC samples. For the diagnosis of PTC for CXCL12 staining of FNA specimens, the calculated values were 93.1% sensitivity, 90.3% specificity, 94.7% positive predictive value, 87.5% negative predictive value, and 89.1% accuracy. CXCL12 had 100% sensitivity and specificity for the 12 cases of atypia of undetermined significance (AUS) diagnosed in FNA specimens. CXCL12 may be a useful diagnostic tool for PTC, especially when the FNA specimen is classified as AUS.

Modulation of CXC-motif chemokine receptor 7, but not 4, expression is related to migration of the human prostate cancer cell LNCaP: regulation by androgen and inflammatory stimuli.

To elucidate the regulation, function of the chemokine CXC-motif ligand 12 (CXCL12) and its receptors (CXCR) 4 and 7 in prostate cancer tumor microenvironment. In-silico-analysis of expression in prostate cancer tissues. In-vitro comparison, testing of regulation in human prostate cancer cells LNCaP, DU145, and PC3. Dihydrotestosterone (DHT) treatments (0-10nM) were for 0-48h. The inflammatory agent Flagellin treatment (20ng/ml) was for 2h. Migration assays were performed for 24h using 10ng/ml CXCL12. Real-time PCR, western analysis, and migration assays were used to determine mRNA, protein, and functional changes, respectively. Malignant prostate cancer tissues exhibit higher CXCR4/7 mRNA ratio, and higher CXCR7 mRNA levels were detected in the androgen-responsive LNCaP cells. Putative androgen-responsive elements were identified in CXCR4, 7 gene, and exposure to DHT, flagellin increased CXCR4 mRNA but decreased CXCR7 mRNA levels in LNCaP cells. Androgen receptor siRNA significantly attenuated the effects of DHT on CXCR4, 7 mRNA in LNCaP cells. However, DHT and flagellin only decrease CXCR7 protein and additively increased migration of LNCaP cells towards CXCL12. Down regulation of CXCR7 protein by DHT and flagellin increased migration, supporting CXCR7 as decoy receptor counteracting CXCL12/CXCR4-mediated migration in prostate cancer cells.

Overexpressed microRNA-103a-3p inhibits acute lower-extremity deep venous thrombosis via inhibition of CXCL12.

Studies have shown that microRNAs (miRNAs) participate in almost all pathological and physiological processes including acute lower-extremity deep venous thrombosis (LEDVT). Here, this study was designed to elucidate the possible function of miR-103a-3p in acute LEDVT. Expression of miR-103a-3p and chemokine C-X-C motif ligand 12 (CXCL12) was initially quantified in plasma collected from 81 LEDVT patients. Then LEDVT mouse models were established by injection with 3% sodium pentobarbital. The interaction between miR-103a-3p and CXCL12 was identified by dual-luciferase reporter gene assay. After gain- and loss-of-function studies, interleukin-6 (IL-6) and IL-8 and tissue factor (TF) levels, and expression of plasminogen activator inhibitors (PAIs), von Willebrand factor (vWF), thromboxane A2 (TH-A2), F4/80, IL-12, Arginase-1 (Arg-1) and CD206 were determined using enzyme-linked immunosorbent assay (ELISA), reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis, respectively. miR-103a-3p was downregulated, while CXCL12 was upregulated in patients and mice with LEDVT. miR-103a-3p targets CXCL12 and inhibited its expression. Overexpressed miR-103a-3p or downregulated CXCL12 decreased expression of IL-6, IL-8, TF, PAIs, vWF, TH-A2, M1 markers (IL-6 and IL-12), yet increased expression of M2 markers (Arg-1 and CD206) in LEDVT mice. Additionally, upregulated miR-103a-3p or silencing CXCL12 suppressed thrombosis in LEDVT mice. However, overexpression of CXCL12 reversed the tendency mentioned above. Altogether, miR-103a-3p can potentially downregulate CXCL12 expression to disrupt inflammatory response and thrombosis, ultimately preventing the development of LEDVT. Our findings underscore a possible alternative therapeutic strategy to limit LEDVT.

HIF signaling in osteoblast-lineage cells promotes systemic breast cancer growth and metastasis in mice

Bone metastasis involves dynamic interplay between tumor cells and the local stromal environment. In bones, local hypoxia and activation of the hypoxia-inducible factor (HIF)-1α in osteoblasts are essential to maintain skeletal homeostasis. However, the role of osteoblast-specific HIF signaling in cancer metastasis is unknown. Here, we show that osteoprogenitor cells (OPCs) are located in hypoxic niches in the bone marrow and that activation of HIF signaling in these cells increases bone mass and favors breast cancer metastasis to bone locally. Remarkably, HIF signaling in osteoblast-lineage cells also promotes breast cancer growth and dissemination remotely, in the lungs and in other tissues distant from bones. Mechanistically, we found that activation of HIF signaling in OPCs increases blood levels of the chemokine C-X-C motif ligand 12 (CXCL12), which leads to a systemic increase of breast cancer cell proliferation and dissemination through direct activation of the CXCR4 receptor. Hence, our data reveal a previously unrecognized role of the hypoxic osteogenic niche in promoting tumorigenesis beyond the local bone microenvironment. They also support the concept that the skeleton is an important regulator of the systemic tumor environment.

Relationship between osteoporosis and expression of Bcl-2 and CXCL12.

The changes of expression of anti-apoptotic factor B-cell lymphoma 2 (Bcl-2) and chemokine C-X-C motif ligand 12 (CXCL12) in the pathological process of osteoporosis (OP) were investigated, to provide new ideas for the diagnosis and treatment of OP. A total of 60 postmenopausal women who needed to undergo hip replacement surgery were enrolled and divided into osteoporosis group (OP, n=32) and control group (CK, n=28) according to the results of dual-energy X-ray bone density measure; after operation, cancellousbone from the femoral head or femoral neck was removed, and osteoblasts and osteoclasts were isolated and cultured in vitro. The proliferation and apoptosis in the two groups of osteoblasts and osteoclasts were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetry and Annexin V/PI double staining method, respectively. The expression levels of Bcl-2 and CXCL12 mRNA and protein in the two groups of osteoblasts and osteoclasts were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The analysis of cell proliferation and apoptosis showed that compared with the CK group, osteoblast proliferation was significantly inhibited and apoptosis rate was distinctly increased in the OP group, compared with the CK group, osteoclast proliferation was distinctly enhanced and apoptosis rate was remarkably reduced in the OP group. The results of RT-qPCR and western blot analysis displayed that Bcl-2 and CXCL12 mRNA and protein levels in osteoblasts of the OP group were significantly lower than those of the CK group, while mRNA and protein levels of Bcl-2 and CXCL12 in osteoclast of the OP group were distinctly increased compared to those in the CK group. The incidence of OP is closely associated with the bone balance maintained by osteoblasts and osteoclasts, and this mechanism may be achieved by inhibiting osteoblast proliferation and osteoclast apoptosis via regulating Bcl-2 and CXCL12 gene expression changes.

The expression of CXCR4 is induced by the luteinizing hormone surge and mediated by progesterone receptors in human preovulatory granulosa cells.

The chemokine CXC motif ligand 12 (CXCL12) and its cognate receptor, CXCR4, have been implicated in the ovulatory process in various animal models. However, little is known about the expression and regulation of CXCL12 and CXCR4 and their functions during the ovulatory period in the human ovary. In this study, we characterized the expression patterns of CXCL12 and CXCR4 in preovulatory follicles collected before the luteinizing hormone (LH) surge and at defined hours after hCG administration in women with the regular menstrual cycle. The levels of mRNA and protein for CXCR4 were increased in granulosa cells of late ovulatory follicles, whereas CXCL12 expression was constant in follicles throughout the ovulatory period. Both CXCR4 and CXCL12 were localized to a subset of leukocytes around and inside the vasculature of human preovulatory follicles. Using a human granulosa cell culture model, the regulatory mechanisms and functions of CXCL12 and CXCR4 expression were investigated. Human chorionic gonadotropin (hCG) stimulated CXCR4 expression, whereas CXCL12 expression was not affected, mimicking in vivo expression patterns. Both RU486 (progesterone receptor antagonist) and CoCl2 (HIFs activator) blocked the hCG-induced increase in CXCR4 expression, whereas AG1478 (EGFR inhibitor) had no effect. The treatment with CXCL12 had no effect on granulosa cell viability but decreased hCG-stimulated CXCR4 expression.

Stromal Cell-Derived Factor 1 Increases Tetrodotoxin-Resistant Sodium Currents Nav1.8 and Nav1.9 in Rat Dorsal Root Ganglion Neurons via Different Mechanisms.

Stromal cell-derived factor 1 (SDF-1)/chemokine CXC motif ligand 12 (CXCL12), a chemokine that is upregulated in dorsal root ganglion (DRG) during chronic pain models, has recently been found to play a central role in pain hypersensitivity. The purpose of present study is to investigate the functional impact of SDF-1 and its receptor, chemokine CXC motif receptor 4 (CXCR4), on two TTXR sodium channels in rat DRG using electrophysiological techniques. Preincubation with SDF-1 caused a concentration-dependent increase of Nav1.8 and Nav1.9 currents amplitudes in acutely isolated small diameter DRG neurons in short-term culture. As to Nav1.9, changes in current density and kinetic properties of Nav1.9 current evoked by SDF-1(50ng/ml) was eliminated by CXCR4 antagonist AMD3100 and phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. The increase in Nav1.9 current was also blocked by pertussis toxin (PTX) but not cholera toxin (CTX), showing involvement of Gi/o but not Gs subunits. As to Nav1.8, inhibitors (AMD3100, PTX, CTX, LY294002) used in present study didn't inhibit the increased amplitude of Nav1.8 current and shifted activation curve of Nav1.8 in a hyperpolarizing direction in the presence of SDF-1 (50ng/ml). In conclusion, our data demonstrated that SDF-1 may excite primary nociceptive sensory neurons by acting on the biophysical properties of Nav1.8 and Nav1.9 currents but via different mechanisms.

CXCL12/CXCR4 axis: an emerging neuromodulator in pathological pain

The roles of chemokine C-X-C motif ligand 12 (CXCL12) and its receptor chemokine C-X-C motif receptor 4 (CXCR4) reveal this chemokine axis as an emerging neuromodulator in the nervous system. In the peripheral and central nervous systems, both CXCL12 and CXCR4 are expressed in various kinds of nociceptive structures, and CXCL12/CXCR4 axis possesses pronociceptive property. Recent studies have demonstrated its critical roles in the development and maintenance of pathological pain, and both neuronal and glial mechanisms are involved in this CXCL12/CXCR4 axis-mediated pain processing. In this review, we summarize the recent development of the roles and mechanisms of CXCL12/CXCR4 axis in the pathogenesis of chronic pain by sciatic nerve injury, human immunodeficiency virus-associated sensory neuropathy, diabetic neuropathy, spinal cord injury, bone cancer, opioid tolerance, or opioid-induced hyperalgesia. The potential targeting of CXCL12/CXCR4 axis as an effective and broad-spectrum pharmacological approach for chronic pain therapy was also discussed.

BMP2 Regulation of CXCL12 Cellular, Temporal, and Spatial Expression is Essential During Fracture Repair.

The cellular and humoral responses that orchestrate fracture healing are still elusive. Here we report that bone morphogenic protein 2 (BMP2)-dependent fracture healing occurs through a tight control of chemokine C-X-C motif-ligand-12 (CXCL12) cellular, spatial, and temporal expression. We found that the fracture repair process elicited an early site-specific response of CXCL12(+)-BMP2(+) endosteal cells and osteocytes that was not present in unfractured bones and gradually decreased as healing progressed. Absence of a full complement of BMP2 in mesenchyme osteoprogenitors (BMP2(cKO/+)) prevented healing and led to a dysregulated temporal and cellular upregulation of CXCL12 expression associated with a deranged angiogenic response. Healing was rescued when BMP2(cKO/+) mice were systemically treated with AMD3100, an antagonist of CXCR4 and agonist for CXCR7 both receptors for CXCL12. We further found that mesenchymal stromal cells (MSCs), capable of delivering BMP2 at the endosteal site, restored fracture healing when transplanted into BMP2(cKO/+) mice by rectifying the CXCL12 expression pattern. Our in vitro studies showed that in isolated endosteal cells, BMP2, while inducing osteoblastic differentiation, stimulated expression of pericyte markers that was coupled with a decrease in CXCL12. Furthermore, in isolated BMP2(cKO/cKO) endosteal cells, high expression levels of CXCL12 inhibited osteoblastic differentiation that was restored by AMD3100 treatment or coculture with BMP2-expressing MSCs that led to an upregulation of pericyte markers while decreasing platelet endothelial cell adhesion molecule (PECAM). Taken together, our studies show that following fracture, a CXCL12(+)-BMP2(+) perivascular cell population is recruited along the endosteum, then a timely increase of BMP2 leads to downregulation of CXCL12 that is essential to determine the fate of the CXCL12(+)-BMP2(+) to osteogenesis while departing their supportive role to angiogenesis. Our findings have far-reaching implications for understanding mechanisms regulating the selective recruitment of distinct cells into the repairing niches and the development of novel pharmacological (by targeting BMP2/CXCL12) and cellular (MSCs, endosteal cells) interventions to promote fracture healing.