Specific Receptor CXCR4 Research Articles

The mechanism of LncRNA01977 in lung adenocarcinoma through the SDF-1/CXCR4 pathway.

BackgroundA significant correlation has been identified between lncRNA and tumor cell resistance, diagnosis, and prognosis. Although mRNA studies have dominated the field of non-coding RNA biology in tumorigenesis in recent years, long-chain non-coding RNA (the biological function) has also attracted increasing attention. However, the lncRNA associated with lung adenocarcinoma (LUAD) remains unexplored. This study used bioinformatics analysis to screen and identify LncRNA01977 as a key oncogenic driver of LUAD.MethodsThe experiment was divided into blank serum group (normal serum medium) and lung compound low, medium and high dose groups (5%, 10%, 15% and 15% lung compound drug serum medium, respectively). Transwell invasion ability of A549 cells was detected, and Western blot tested A549 cells SDF-1 specific receptor CXCR4, and CXCR4 gene expression in A549 cells were determined by reverse transcription–polymerase chain reaction (RT-PCR). In addition, western blotting, MTT proliferation test, colony formation test and apoptosis detection techniques were used to explore the mechanism of LncRNA01977's effects on LUAD.ResultsIn vitro assays demonstrated that LncRNA01977 can significantly promote the progression of LUAD and that stromal cells in tumor microenvironment secrete chemokine CXCL12, also known as stromal derived factor-1 (SDF-1), and its receptor CXCR4 is low expressed in normal tissues and high expressed in LUAD tissues. Lung cancer patients with high expression of CXCR4 are more prone to metastasis.ConclusionsLncRNA01977 can be used as a new prognostic indicator of LUAD, and can help patients to find more effective target treatment options for LUAD.

Characterization of CD4+ Lymphocyte From Bone Marrow Stem Cell Using Indirect Immunofluoresence For HIV & AIDS Treatment

Acquired immune deficiency syndrome (AIDS) is caused by Human Immunodeficiency Virus (HN). At the beginning of infection, gpl20 virus interacts with CD4 receptor at the surface of the target cell. The interaction between gpI20 and CD4 leads to the occurrence of the binding of specific chemokine receptor CXCR4 and CCR5, which are also present on the membrane of the target cell. Therefore, CCR5 arid CXCR4 also determine the fate of the target cell. It is the performance of CCR5 and CXCR4, guided by controlling gene that determines susceptibility or resistance to HN infection. Coding gene CCR5 may mutate to become protective or resistant against HTV infection. In homozygote individuals, it tends to be resistant against infection while in heterozygote individuals it tends to be susceptible to HN infection. Objective: To characterize TCD4 lymphocyte in the next that is resistant against HN infection by using gene therapy deletion 32 CCR5 to use for HTV & AIDS treatment. Method: Sample collection, mononucleated cell collection, lymphocyte culture, CD4 identification, CCR5 variance analysis, co-cultivation with PBMC HN and comparison to control. Result: This study was performed in several steps, such as mononucleated cell isolation, followed with cell culture, lymphocyte purification, lymphocyte and CD4 expression identification. Conclusion: Lymphocyte T CD4 had been mature after seven passages, once passage is about 5 days so for maturity lymphocyte T CD4 need 35 days and that cell as be candidate to resistant against HN infection by using gene therapy deletion 32 CCR5 to use for HN & AIDS treatment.

Discovery of Potential Chemical Probe as Inhibitors of CXCL12 Using Ligand-Based Virtual Screening and Molecular Dynamic Simulation.

CXCL12 are small pro-inflammatory chemo-attractant cytokines that bind to a specific receptor CXCR4 with a role in angiogenesis, tumor progression, metastasis, and cell survival. Globally, cancer metastasis is a major cause of morbidity and mortality. In this study, we targeted CXCL12 rather than the chemokine receptor (CXCR4) because most of the drugs failed in clinical trials due to unmanageable toxicities. Until now, no FDA approved medication has been available against CXCL12. Therefore, we aimed to find new inhibitors for CXCL12 through virtual screening followed by molecular dynamics simulation. For virtual screening, active compounds against CXCL12 were taken as potent inhibitors and utilized in the generation of a pharmacophore model, followed by validation against different datasets. Ligand based virtual screening was performed on the ChEMBL and in-house databases, which resulted in successive elimination through the steps of pharmacophore-based and score-based screenings, and finally, sixteen compounds of various interactions with significant crucial amino acid residues were selected as virtual hits. Furthermore, the binding mode of these compounds were refined through molecular dynamic simulations. Moreover, the stability of protein complexes, Root Mean Square Deviation (RMSD), Root Mean Square Fluctuation (RMSF), and radius of gyration were analyzed, which led to the identification of three potent inhibitors of CXCL12 that may be pursued in the drug discovery process against cancer metastasis.

The expressions and the roles of SDF-1/CXCR-4 and SDF-1/CXCR-4 in human endometriosis

Objective: To investigate the expressions and significances of SDF-1 and its receptor CXCR-4 in endometriosis. Methods: 50 hysteromyoma patients treated at Beijing Tongren Hospital, Capital Medical University between 1(st) January 2016 and 31(st) December 2017 were divided into control group, that is, non-endometriosis group, while another 50 endometriosis patients were divided into experimental group.The endometrial tissues, endometriosis lesions, and peritoneal fluid samples of hysteromyoma patients were collected by operation.RT-PCR, ELISA and immunohistochemistry were adopted to detect the expressions of SDF-1 and CXCR-4 in the two groups.Cell count was used to analyze the roles of SDF-1 and CXCR4 in the mitosis and proliferation of endometrial stromal cells. Results: The mean value of SDF-1 and CXCR-4 expressions in ascites or peritoneal fluid of endometriosis patients were (2.56±0.33) mg/L and (4.47±0.32) mg/L, respectively. The mean concentrations in ascites or peritoneal fluid in hysteromyoma patients were (1.39±0.36) mg/L and (3.16±0.32) mg/L, respectively.The expressions of SDF-1 and CXCR-4 in ascites or peritoneal fluid of endometriosis patients were both significantly higher than those of patients in non-endometriosis group (P<0.05). SDF-1 and CXCR-4 were expressed in both endometriosis lesions and the glandular epithelial cells and mesenchymal cells of normal endometrial tissue.Positive staining sites were located in the cytoplasm.A value was used to calculate and analyze the expression of immune staining.The mean A value of SDF-1 and CXCR-4 in endometriosis group were 0.21±0.13 and 0.21±0.13, respectively, and the mean A value in normal endometrial tissues were 0.15±0.13 and 0.14±0.13, respectively.The expressions of these two in endometrial tissues were significantly higher than that in normal endometrial tissues, and the differences were statistically significant (P<0.05). The expression of CXCR-4 mRNA was abundant in the mesenchymal cells of endometriosis cultured in vitro.SDF-1 promoted the mitosis and proliferation of endometrial stromal cells cultured in vitro in a dose-dependent manner.The neutralizing antibody against CXCR-4 was obviously inhibited. Conclusion: The high expressions of SDF-1 and CXCR-4 in endometriosis as well as SDF-1 through its specific receptor CXCR-4 promoted the mitosis and proliferation of endometrial stromal cells, suggesting that SDF-1 and CXCR-4 played important roles in the pathogenesis of endometriosis.

The Serum Concentrations of Chemokine CXCL12 and Its Specific Receptor CXCR4 in Patients with Esophageal Cancer.

Objectives. Recent investigations have suggested that upregulated levels of inflammatory biomarkers, such as chemokines, may be associated with development of many malignancies, including esophageal cancer (EC). Based on our knowledge, this study is the first to assess the serum concentration of chemokine CXCL12 and its specific receptor CXCR4 in the diagnosis of EC patients. Material and Methods. The present study included 79 subjects: 49 patients with EC and 30 healthy volunteers. The serum concentrations of CXCL12 and CXCR4 and classical tumor markers such as carcinoembryonal antigen (CEA) and squamous cell cancer antigen (SCC-Ag) were measured using immunoenzyme assays, while C-reactive protein (CRP) levels were assessed by immunoturbidimetric method. Moreover, diagnostic criteria of all proteins tested and the survival of EC patients were assessed. Results. The serum concentrations of CXCL12 were significantly higher, while those of its receptor CXCR4 were significantly lower in EC patients compared to healthy controls. The diagnostic sensitivity, negative predictive value, and accuracy of CXCR4 were the highest among all analyzed proteins and increased for combined analysis with classical tumor markers and CRP levels. Conclusion. Our findings suggest that serum CXCR4 may improve the diagnosis of EC patients, especially in combination with classical tumor markers.

Targeting SDF-1 in multiple myeloma tumor microenvironment

Multiple myeloma (MM) is a type of B-cell malignancy that remains incurable to date. The bone marrow (BM) microenvironment plays a crucial role in MM progression. The chemokine SDF-1 (CXCL12) is an important actor of the BM microenvironment that has the ability to regulate numerous processes related to its malignant transformation during MM development. The activity of SDF-1 is mainly mediated by its specific receptor CXCR4, which is expressed at the surface of MM cells and various other BM cell types. Current treatments available for MM patients mainly target tumor cells but have limited effects on the BM microenvironment. In this context, SDF-1 and CXCR4 represent ideal targets for the normalization of the MM-supportive BM microenvironment. The present review focuses on the activity of SDF-1 in the MM BM microenvironment and the current efforts carried out to target the SDF-1/CXCR4 axis for treatment of MM.

Early in-situ cellularization of a supramolecular vascular graft is modified by synthetic stromal cell-derived factor-1α derived peptides

In an in-situ approach towards tissue engineered cardiovascular replacement grafts, cell-free scaffolds are implanted that engage in endogenous tissue formation. Bioactive molecules can be incorporated into such grafts to facilitate cellular recruitment. Stromal cell derived factor 1α (SDF1α) is a powerful chemoattractant of lymphocytes, monocytes and progenitor cells and plays an important role in cellular signaling and tissue repair. Short SDF1α-peptides derived from its receptor-activating domain are capable of activating the SDF1α–specific receptor CXCR4. Here, we show that SDF1α-derived peptides can be chemically modified with a supramolecular four-fold hydrogen bonding ureido-pyrimidinone (UPy) moiety, that allows for the convenient incorporation of the UPy-SDF1α-derived peptides into a UPy-modified polymer scaffold. We hypothesized that a UPy-modified material bioactivated with these UPy-SDF1α-derived peptides can retain and stimulate circulating cells in an anti-inflammatory, pro-tissue formation signaling environment. First, the early recruitment of human peripheral blood mononuclear cells to the scaffolds was analyzed in vitro in a custom-made mesofluidic device applying physiological pulsatile fluid flow. Preferential adhesion of lymphocytes with reduced expression of inflammatory factors TNFα, MCP1 and lymphocyte activation marker CD25 was found in the bioactivated scaffolds, indicating a reduction in inflammatory signaling. As a proof of concept, in-vivo implantation of the bioactivated scaffolds as rat abdominal aorta interposition grafts showed increased cellularity by CD68+ cells after 7 days. These results indicate that a completely synthetic, cell-free biomaterial can attract and stimulate specific leukocyte populations through supramolecular incorporation of short bioactive SDF1α derived peptides.

Enriched Environment Altered Aberrant Hippocampal Neurogenesis and Improved Long-Term Consequences After Temporal Lobe Epilepsy in Adult Rats.

Abnormal hippocampal neurogenesis is thought to contribute to cognitive impairments in chronic temporal lobe epilepsy (TLE). Stromal cell-derived factor-1 (SDF-1) and its specific receptor CXCR4 play important roles in neurogenesis. We investigated whether enriched environment (EE) might be beneficial for TLE. Adult rats were randomly assigned as control rats, rats subjected to status epilepticus (SE), or post-SE rats treated with EE for 30 days. We used immunofluorescence staining to analyze the hippocampal neurogenesis and Nissl staining to evaluate hippocampal damage. Electroencephalography was used to measure the duration of spontaneous seizures. Cognitive function was evaluated by Morris water maze. Western blot was used to measure the expression of SDF-1 and CXCR4 in the hippocampus. In the present study, we found the TLE model resulted in aberrant neurogenesis such as reduced proliferation, intensified dendritic development of newborn neurons, as well as spontaneous seizures and cognitive impairments. More importantly, EE treatment significantly increased the cell proliferation and survival, extended the apical dendrites, and delayed the attenuation of the expression of SDF-1 and CXCR4, accompanied by decreased long-term seizure activity and improved cognitive impairments in adult rats after TLE. These results provided morphological evidence that EE might be beneficial for treating TLE.

CXCR4 Antagonist AMD3100 Suppresses the Long-Term Abnormal Structural Changes of Newborn Neurons in the Intraventricular Kainic Acid Model of Epilepsy.

Abnormal hippocampal neurogenesis is a prominent feature of temporal lobe epilepsy (TLE) models, which is thought to contribute to abnormal brain activity. Stromal cell-derived factor-1 (SDF-1) and its specific receptor CXCR4 play important roles in adult neurogenesis. We investigated whether treatment with the CXCR4 antagonist AMD3100 suppressed aberrant hippocampal neurogenesis, as well as the long-term consequences in the intracerebroventricular kainic acid (ICVKA) model of epilepsy. Adult male rats were randomly assigned as control rats, rats subjected to status epilepticus (SE), and post-SE rats treated with AMD3100. Animals in each group were divided into two subgroups (acute stage and chronic stage). We used immunofluorescence staining of BrdU and DCX to analyze the hippocampal neurogenesis on post-SE days 10 or 74. Nissl staining and Timm staining were used to evaluate hippocampal damage and mossy fiber sprouting, respectively. On post-SE day 72, the frequency and mean duration of spontaneous seizures were measured by electroencephalography (EEG). Cognitive function was evaluated by Morris water maze testing on post-SE day 68. The ICVKA model of TLE resulted in aberrant neurogenesis such as altered proliferation, abnormal dendrite development of newborn neurons, as well as spontaneous seizures and spatial learning impairments. More importantly, AMD3100 treatment reversed the aberrant neurogenesis seen after TLE, which was accompanied by decreased long-term seizure activity, though improvement in spatial learning was not seen. AMD3100 could suppress long-term seizure activity and alter adult neurogenesis in the ICVKA model of TLE, which provided morphological evidences that AMD3100 might be beneficial for treating chronic epilepsy.

Construction of a CXCL12-KDEL fusion gene to inhibit head and neck squamous cell carcinoma metastasis by intracellular sequestration of CXCR4.

The CXCL12-CXCR4 biological axis consisting of the chemotactic factor CXCL12 and its specific receptor CXCR4 plays an important role in oral cancer metastasis. High expression of CXCR4 may help oral squamous cancer cells invade local tissues and metastasize to lymph nodes. No obvious association was observed between CXCL12 expression and lymph node metastasis, suggesting that CXCL12 chemotaxis may only be related to CXCR4 expression on the tumor cell membrane. KDEL can be retained by receptors on the surface of the intracellular endoplasmic reticulum (ER) and also be called an ER retention signal sequence. So we adopted the KDEL sequence in this study to generate a CXCL12-KDEL fusion protein in combination with a traceable E-tag label. As such, CXCL12 was retained in the ER. Specific receptor CXCR4 binds to the CXCL12-KDEL, was also retained in the ER, and was thus prevented from reaching the oral squamous cancer cell surface. We reduced the cell surface level of CXCR4 and called the technique “intracellular sequestration.” By this way, we have finished blocking of CXCL12-CXCR4 biological axis and inhibiting lymph node metastasis of oral carcinoma.

Effects of stromal cell derived factor-1 and CXCR4 on the promotion of neovascularization by hyperbaric oxygen treatment in skin flaps

Hyperbaric oxygen (HBO) is known to increase the survival of skin flaps by promoting neovascularization; however, the detailed mechanisms involved are not fully understood. In the present study, we aimed to characterize the effects of HBO treatment on neovascularization and skin flap survival. We also analyzed the mechanisms associated with the expression of angiogenic molecules, such as stromal cell derived factor-1 (SDF‑1) and its specific receptor CXCR4, to assess the effects of SDF-1 and CXCR4 on the promotion of neovascularization by HBO treatment in skin flaps. The epigastric pedicle skin flap model was established in rats that were randomly divided into the following groups: i) sham‑operated (SH group); ii) ischemia followed by reperfusion and analysis on the third and fifth day (IR3d and IR5d groups, respectively) postoperatively; iii) ischemia followed by reperfusion, HBO treatment and analysis on the third and fifth day (HBO3d and HBO5d groups, respectively) postoperatively. In the two HBO groups, animals received 1 h of HBO treatment in a 2.0 ATA chamber with 100% O2 twice per day for 3 days and then daily for 2 consecutive days following surgery. On the postoperative third and fifth day, skin flap survival measurement, histological analysis, immunohistochemical staining and western blotting for SDF‑1 and CXCR4 expression, were performed. Compared with those of the IR groups, skin flap survival, microvessel density (MVD) and expression of SDF‑1 and CXCR4 proteins were significantly increased in the HBO groups. Pearson's correlation analysis demonstrated a positive correlation between MVD and the high expression of SDF‑1 and CXCR4 following HBO treatment. Results of this study suggested that the effects of HBO treatment in promoting neovascularization may be explained by the upregulation of SDF‑1 and CXCR4 expression in the skin flaps of rats.

Stromal cell-derived factor-1 and its receptor CXCR4 in adult neurogenesis after cerebral ischemia

Stromal cell-derived factor-1 was originally found as a chemoattractant for immune cells. Later it was shown that stromal cell-derived factor-1 and its specific receptor CXCR4 were widely expressed in the developing and mature brains. They participate in a variety of physiological and pathological processes including brain development, angiogenesis, neurodegeneration and neurogenesis. Stromal cell-derived factor-1/CXCR4 plays a particularly important role in adult neurogenesis through mediating the proliferation of neurogenitors, regulating the migration, differentiation, as well as functional integration of newborn neurons into existing networks. After stroke, adult neurogenesis in both the subventricular zone and subgranular zone is robustly increased and stromal cell-derived factor-1 and matrix metalloproteinases are released by damaged tissue. Stromal cell-derived factor-1 promotes the proliferation of neuroblasts and their migration to injured areas. However, the majority of the neuroblasts produced after stroke undergo apoptosis and only a few differentiate and survive in the long-term. The interaction of stromal cell-derived factor-1 and matrix' metalloproteinases may contribute to the unfavorable local microenvironment diminishing the survival of newborn neurons. Stromal cell-derived factor-1/matrix metalloproteinases and their downstream pathways may provide a new target for the treatment of stroke.

Will the Stroma-derived Factor-1α (CXCL12)/CXCR4 Pathway Become a Major Concern for Advanced Colorectal Cancer?

See Article on Page 27-34 The chemokine stroma-derived factor (SDF-1α/CXCL12) is a homeostatic chemokine. The major function of this chemokine is to regulate hematopoietic cell trafficking and secondary lymphoid tissue architecture [1]. SDF-1α is also widely expressed in various organs. Including the heart, liver, brain, kidney, skeletal muscle, and lymphoid organs, and it plays multiple roles in tumor pathogenesis. SDF-1α has been demonstrated to promote tumor growth, enhance tumor angiogenesis, participate in tumor metastasis, and contribute to immunosuppressive networks within the tumor microenvironment. SDF-1α expression is reported in ovarian cancer, breast cancer [2], colorectal cancer, pancreatic cancer, prostate cancer, thyroid cancer, and many other human tumors. SDF-1α can increase the invasiveness and the migration of cancer cells, and its levels are correlated with node involvement and long-term survival in patients with breast cancer. SDF-1 may, therefore, have potential value in assessing clinical outcomes of patients with breast cancer [3]. Although colorectal cancer (CRC) tissues contain SDF-1α-positive stromal cells, immunohistochemistry clearly demonstrated that the cancerous cells in more than 50% of the CRC samples examined had much stronger expression of SDF-1α than their neighboring normal colonic epithelial cells. Accordingly, as with CXCR4 overexpression, the SDF-1α/CXCR4 pathway appears to play important roles in the progression of CRC [4]. In this study, the authors merely measured the SDF-1α expression level in the normal colonic mucosa and in colorectal cancer tissue. If this study had included the SDF-1α specific receptor CXCR4 expression level, the authors would have obtained better results. Nevertheless, the results are quite impressive. SDF-1α expression was highly correlated with pericolic lymph-node metastasis, distant metastasis, tumor-node-metastasis stage and lymphovascular invasion. Strong SDF-1α expression was inversely related with patients' survival, suggesting suggest SDF-1α could be a prognostic factor. Further study evaluating the distinctive value of SDF-1α expression in clinical practice may be warranted. According to the literature, it is evident that manipulation of this pathway represents a new strategy for cancer treatment. CXCR4 antagonists, such as Plerixafor (AMD3100) and T140 analogues (TN14003/BKT140), and blocking antibodies toward CXCR4 or SDF-1α are being investigated in various cancer settings. In an in vitro study using a colorectal cancer cell line, results indicate that a CXCR4-antagonistic therapy might prevent tumor cell dissemination and metastasis in CRC patients, consequently improving survival [5]. Of course, we need to bear in mind that although targeting CXCR4/CXCL12 is an attractive option in treating human tumors, it is certain that to gain effective, reliable, and consistent clinical efficacy, a definitive combinatorial therapeutic regimen should be found.

CHARACTERIzATION of CD4 + T LYMPHOCYTE FROM BONE MAROW STEM CELL USING INDIRECT IMMUNOFLUORESENCE FOR HIV &amp; AIDS TREATMENT

Acquired immune deficiency syndrome (AIDS) is caused by Human Immunodeficiency Virus (HIV). At the beginning of infection, gp120 virus interacts with CD4 receptor at the surface of the target cell. The interaction between gp120 and CD4 leads to the occurrence of the binding of specific chemokine receptor CXCR4 and CCR5, which are also present on the membrane of the target cell. Therefore, CCR5 and CXCR4 also determine the fate of the target cell. It is the performance of CCR5 and CXCR4, guided by controlling gene that determines susceptibility or resistance to HIV infection. Coding gene CCR5 may mutate to become protective or resistant against HIV infection. In homozygote individuals, it tends to be resistant against infection, while in heterozygote individuals it tends to be susceptible to HIV infection. Objective: To characterize TCD4 lymphocyte in the next that is resistant against HIV infection by using gene therapy deletion 32 CCR5 to use for HIV &amp; AIDS treatment. Method: Sample collection, mononucleated cell collection, lymphocyte culture, CD4 identification, CCR5 variance analysis, co-cultivation with PBMC HIV and comparison to control. Result: This study was performed in several steps, such as mononucleated cell isolation, followed with cell culture, lymphocyte purification, lymphocyte and CD4 expression identification. Conclusion: Lymphocyte T CD4 had been mature after seven passages, once passage is about 5 days so for maturity lymphocyte T CD4 need 35 days and that cell as be candidate to resistant against HIV infection by using gene therapy deletion 32 CCR5 to use for HIV &amp; AIDS treatment.

The chemotactic effects of stromal cell derived factor-1 on neural stem cells

Objective To investigate the effect of stromal cell derived factor-1 ( SDF-1) on the regulation of neural stem cells (NSCs) migration. Methods NSCs were obtained from the cerebral cortex of embryonic GFP transgenic rats. After cell cultured in vitro, CXCR4, specific receptor of SDF-1, was detected by fluorescence immunocytochemistry. Using Blind-Well chambers, the chemotactic effects of SDF-1 was investigated by counting the cells which had crossed 8μm pore membrane and adhered to the superficies inferia of the membrane when confronted with varying concentrations of SDF-1α (0, 1, 10, 50, 100, 500 and 1000 μg/L) and the agonist or antagonist of CXCR4. Results Neurospheres were formed, which expressed GFP and were capable of differentiating into neurons (β-tubulin + ) and astrocytes (GFAP + ) in media without mitogens. Fluorescence immunocytochemistry showed that CXCR4 and Nestin were co-expressed in NSCs. SDF-1 showed great chemotaxis to NSCs, and the amount of cells migrating through the membrane in 500 μg/L SDF-1 group was more than that in other groups (P < 0. 05). The number of cells crossing the membrane could be augmented and diminished by the agonist and antagonist of CXCR4 respectively. Conclusion SDF-1 binding to its specific receptor CXCR4 was capable of inducing NSCs migrating directionally to the source of SDF-1. Key words: Neural stem cells; Chemotaxis; Stromal cell derived factor-1

The chemokine CXCL12 promotes survival of postmitotic neurons by regulating Rb protein

Postmitotic neurons need to keep their cell cycle under control to survive and maintain a differentiated state. This study aims to test the hypothesis that the chemokine CXCL12 regulates neuronal survival and differentiation by promoting Rb function, as suggested by previous studies showing that CXCL12 protects neurons from apoptosis induced by Rb loss. To this end, the effect of CXCL12 on Rb expression and transcriptional activity and the role of Rb in CXCL12-induced neuronal survival were studied. CXCL12 increases Rb protein and RNA levels in rat cortical neurons. The chemokine also stimulates an exogenous Rb promoter expressed in these neurons and counteracts the inhibition of the Rb promoter induced by E2F1 overexpression. Furthermore CXCL12 stimulates Rb activity as a transcription repressor. The effects of CXCL12 are mediated by its specific receptor CXCR4, and do not require the presence of glia. Finally, shRNA studies show that Rb expression is crucial to the neuroprotective activity of CXCL12 as indicated by NMDA-neurotoxicity assays. These findings suggest that proper CXCR4 stimulation in the mature CNS can prevent impairment of the Rb-E2F pathway and support neuronal survival. This is important to maintain CNS integrity in physiological conditions and prevent neuronal injury and loss typical of many neurodegenerative and neuroinflammatory conditions.

Bone Marrow Stromal Cells Promote Neurite Extension in Organotypic Spinal Cord Slice: Significance for Cell Transplantation Therapy

Objective. Recent reports have indicated that bone marrow stromal cells (BMSCs) have the potential to improve neurological function when transplanted into models of central nervous system (CNS) disorders, including traumatic spinal cord injury. In this study, the authors aimed to clarify the underlying mechanism through which BMSCs supported CNS regeneration in the spinal cord. Methods. The authors topically applied mouse BMSCs expressing green fluorescence protein (0.4-4 × 104 cells) on the organotypic spinal cord slice culture prepared from 6-day-old rat pups (n = 17). They were co-cultured for 3 weeks after the slice culture started, and the behavior of the applied BMSCs was serially observed using a fluorescence bioimaging technique. The authors completed a histological analysis at the end of the co-cultures and evaluated the profiles of the cultured BMSCs using microarray and immunocytochemistry techniques. Results. The fluorescence bioimaging showed that the BMSCs survived and made a cluster on the slice during the experiments. They also induced a morphological change in the slice within 48 hours of co-culture. Immunohistochemistry analysis showed that the BMSCs promoted a marked neurite extension toward their cluster and some of the BMSCs expressed Tuj-1, an early neuronal marker. Analysis by microarray and immunocytochemistry revealed that BMSCs highly expressed the matrix metalloproteinases (MMPs), stromal cell—derived factor-1, and its specific receptor CXCR4. Conclusions . These findings suggest that the donor BMSCs can support CNS regeneration due to their acquisition of a suitable environment for differentiation and promotion of neurite extension via MMPs and chemokines.

A small proportion of mesenchymal stem cells strongly expresses functionally active CXCR4 receptor capable of promoting migration to bone marrow

AbstractHoming of bone marrow stromal cells (MSCs) to bone and bone marrow after transplantation, important for the correction of conditions such as metabolic storage disorders, can occur but with poor efficiency. Substantial improvements in engraftment will be required in order to derive a clinical benefit from MSC transplantation. Chemokines are the most important factors controlling cellular migration. Stromal-derived factor-1 (SDF-1) has been shown to be critical in promoting the migration of cells to the bone marrow, via its specific receptor CXCR4. The aim of our study was to investigate CXCR4 expression on MSCs and its role in mediating migration to bone marrow. We show that CXCR4, although present at the surface of a small subset of MSCs, is important for mediating specific migration of these cells to bone marrow. (Blood. 2004; 104:2643-2645)