Role Of Stromal Cell-derived Factor-1 Research Articles

The role of Stromal Cell-Derived Factor 1 (SDF-1) and Transforming Growth-Factor-Beta 1 (TGF-?1) levels in Packed Red Cells (PRC) as the indicator of storage lesion at Sanglah Hospital-Blood Bank, Bali, Indonesia

Background: Packed Red Cells (PRC) is one of the blood component obtained from the whole blood through the removal of blood plasma. The storage of PRC aims to maintain the viability and function of erythrocytes by reducing cell metabolic activity. However, PRC's biochemistry changes could occur through storage lesion by releasing Stromal Cell-Derived Factor 1 (SDF-1) and Transforming Growth Factor-Beta 1 (TGF-?1) that affect the erythrocytes metabolism and viability prior to transfusion. This study aims to evaluate the increase of SDF-1 and TGF-?1 levels in PRC as the indicator of storage lesion at Sanglah Hospital-Blood Bank, Bali, Indonesia.Methods: An observational cross-sectional study using randomized post-test only without control group design was conducted at Sanglah Hospital-Blood Bank, Bali. The consecutive random sampling technique was used in this study to the PRC, who met the inclusion criteria. Samples of the SDF-1 group (N=84) were divided into 3 such as Group 1 (1-7 days), Group 2 (8-14 days), and Group 3 (15-21 days). However, 53 PRC was divided into 2 groups as Group 1 (1-7 days) and Group 2 (8-14 days). The SDF-1 and TGF-?1 levels were evaluated for each group using Human SDF-1/CXCL12 and TGF-?1 Kit from Elabcience® by ELISA method. Data were analyzed using SPSS version 25 for Windows software.Results: The median levels of SDF-1 in Group 1 group was 0.385 (0.050-1.020) ng/mL, followed by 0.455 (0.330-0.750) ng/ml in Group 2, and 0.490 (0.380-0.920) ng/ml in Group 3 (p<0.05). The mean of TGF-?1 levels was slightly higher in Group 1 (2,365.21±715.96 pg/ml) compared with Group 2 (2,210.39±994.68 pg/ml) (p=0.523). There was a significant difference in SDF-1 levels in Group 1-Group 2 (P=0.041) and Group 1-Group 3 (P=0.000) groups; however, no significant difference was found in Group 2-Group 3 (P=0.133) using the Mann-Whitney test. The Spearman's rho test found a moderate positive correlation between SDF-1 levels and storage time by day (r=0.546; P=0.000). In addition, based on the Pearson correlation test, there was a weak positive correlation between TGF-?1 levels and storage time by day (r=0.461; p=0.001).Conclusion: The increase of SDF-1 and TGF-?1 levels in PRC by days of storage time could be used as the indicator for storage lesion at Sanglah General Hospital-Blood Bank, Bali, Indonesia.

Role of Stromal Cell-Derived Factor-1 in Endothelial Progenitor Cell-Mediated Vascular Repair and Regeneration.

Endothelial progenitor cells (EPCs) are immature endothelial cells that participate in vascular repair and postnatal neovascularization and provide a novel and promising therapy for the treatment of vascular disease. Studies in different animal models have shown that EPC mobilization through pharmacological agents and autologous EPC transplantation contribute to restoring blood supply and tissue regeneration after ischemic injury. However, these effects of the progenitor cells in clinical studies exhibitmixed results. The therapeutic efficacy of EPCs is closely associated with the number of the progenitor cells recruited into ischemic regions and their functional abilities and survival in injury tissues. In this review, we discussed the regulating role ofstromal cell-derived factor-1(also known CXCL12, SDF-1) in EPC mobilization, recruitment, homing, vascular repair and neovascularization, and analyzedthe underlying machemisms of these functions. Application of SDF-1 to improve the regenerative function of EPCs following vascular injurywas also discussed. SDF-1plays a crucial role in mobilizing EPC from bone marrowinto peripheral circulation, recruiting the progenitor cells to target tissue and protecting against cell death under pathological conditions; thus improve EPC regenerative capacity. SDF-1 are crucial for regulating EPC regenerative function, andprovide a potential target for improve therapeutic efficacy of the progenitor cells in treatment of vascular disease.

BCR activated CLL B cells use both CR3 (CD11b/CD18) and CR4 (CD11c/CD18) for adhesion while CR4 has a dominant role in migration towards SDF-1

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia in the western world. In previous studies, various proportion of patients was found to carry CD11b+ or CD11c+ B cells whose presence was an unfavourable prognostic factor. The exact mechanism however, how these receptors contribute to the pathogenesis of CLL has not been revealed so far. Here we analysed the role of CD11b and CD11c on B cells of CLL patients in the adhesion to fibrinogen and in the migration towards stromal cell derived factor-1 (SDF-1) and studied the role of CR4 in the adherence of the CD11c+ B cell line BJAB. We observed that both CR3 and CR4 mediate adhesion of the malignant B cells. Moreover, we found, that CR4 was strongly involved in the migration of the leukemic cells towards the chemoattractant SDF-1. Our data suggest that CR3 and CR4 are not only passive markers on CLL B cells, but they might contribute to the progression of the disease. Since the role of SDF-1 is prominent in the migration of CLL cells into the bone marrow where their survival is supported, our findings help to understand how the presence of CD11c on leukemic B cells can worsen the prognosis of chronic lymphocytic leukaemia.

Exogenous stromal cell-derived factor-1 (SDF-1) suppresses the NLRP3 inflammasome and inhibits pyroptosis in synoviocytes from osteoarthritic joints via activation of the AMPK signaling pathway

ObjectiveNLRP3 inflammasome may play a key role in OA pathogenesis. Stromal cell-derived factor-1 (SDF-1) is a homeostatic CXC chemokine. Since the role of SDF-1 in OA has not been explored, this study aimed to examine the effect of SDF-1 on NLRP3 inflammasome and pyroptosis in synoviocytes from OA joints.Materials and methodsHuman synovium was obtained from OA patients for isolation of primary synoviocytes and a murine model of collagenase-induced OA was established for testing intra-articular injections of SDF-1. Immunoblotting assays were used to examine the effects and underlying mechanism of action of SDF-1 on NLRP3 inflammasome and synoviocyte pyroptosis in synoviocytes. Inhibitors of AMPK and PI3K–mTOR were utilized to investigate the key signaling pathways involved in SDF-1-mediated OA inflammasome formation and pyroptosis.ResultsSynoviocytes from OA joints exhibited significantly higher expression of NLRP3 inflammasome and biomarkers of synoviocyte pyroptosis relative to healthy individuals. This was confirmed in the collagenase-induced OA model, where OA synoviocytes had a significantly lower SDF-1 expression than healthy ones. SDF-1 treatment in synoviocytes of OA patients and collagenase-induced OA led to significant downregulation in the expression of NLRP3 inflammasome and synoviocyte pyroptosis biomarkers. Inhibition of the AMPK signaling pathway significantly suppressed the inhibitory effect of SDF-1 on NLRP3 inflammasome expression of OA synoviocytes. However, blocking the SDF-1-activated PI3K–mTOR signaling pathway could still suppress the expression of NLRP3 inflammasome and synoviocyte pyroptosis biomarkers.ConclusionsSDF-1 ameliorates NLRP3 inflammasome and pyroptosis in OA synoviocytes through activation of the AMPK signaling pathway. Therefore, SDF-1 may be a novel therapeutic target for OA.

Construction and a preliminary study of paracrine effect of bone marrow-derived endothelial progenitor cell sheet

The release of paracrine factors from endothelial progenitor cell (EPC) sheet is a central mechanism of tissue repair. The purpose of this study was to constuct the rat bone marrow derived-endothelial progenitor cell (BM-EPCs) sheet and investigate invest the role of stromal cell-derived factor-1α (SDF-1α)/CXCR4 axis in the biological function of BM-EPCs sheet. BM-EPC cells were identified by the cell-surface markers-CD34/CD133/VE-cadherin/KDR using flow cytometry and dual affinity for acLDL and UEA-1. After 7 days of incubation, the BM-EPC single-cell suspensions were seeded on thermo-sensitive plate to harvest the BM-EPC cell sheets. The expression levels of SDF-1α/CXCR4 axis-associated genes and proteins were examined using RT-qPCR and western blot analysis, and enzyme-linked immunosorbent assay (ELISA) was applied to determine the concentration of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and SDF-1α in the cell culture medium. The BM-EPC cell sheets were successfully harvested. Moreover, BM-EPC cell sheets have superior migration and tube formation activity when compared with single cell suspension. When capillary-like tube were formed from EPCs sheets, the releasing of paracrine factors such as VEGF, EGF and SDF-1α were increased. To reveal the mechanism of tube formation of BM-EPCs sheets, our research showed that the activation of PI3K/AKT/eNOS pathway was involved in the process, because the phosphorylation of CXCR, PI3K, AKT and eNOS were increased. BM-EPC cell sheets have superior paracrine and tube formation activity than the BM-EPC single-cell. The strong ability to secrete paracrine factors was be potentially related to the SDF-1α/CXCR4 axis through PI3K/AKT/eNOS pathway.

Elevation of stromal cell-derived factor 1 and C-X-C chemokine receptor type 4 in white matter damage treatment with recombinant human erythropoietin and human umbilical cord mesenchymal stem cells in a rat model of preterm birth.

To investigate the role of stromal cell-derived factor 1 (SDF-1) and C-X-C chemokine receptor type 4 (CXCR-4) in the premature brain with white matter damage (WMD) undergoing treatment with human umbilical cord mesenchymal stem cells (hUC-MSCs) and recombinant human erythropoietin (rhEPO). Three-day-old Sprague-Dawley (SD) rats were randomly divided into sham operation group, hypoxia-ischemia (HI) group, rhEPO treated HI group, hUC-MSCs treated HI group, and rhEPO+hUC-MSCs treated HI group. WMD was established in all groups except the Sham group. SDF-1 and CXCR-4 levels in each group were detected at postnatal day (P) 5, P7, and P14. Pathological changes were assessed via HE staining at P14 and neuroethological tests were performed at P28. The rhEPO and hUC-MSCs intervention reduced injury area, increased body weight at P7, and improved neurobehavioral scores at P28. Furthermore, their combined use proved even more beneficial. SDF-1 levels in the rhEPO group were higher than those in the other groups and highest in the hUC-MSCs+rhEPO group (all p<.01). SDF-1 levels in the hUC-MSCs+rhEPO and rhEPO groups were increased at P5 and reached a peak at P7. CXCR-4 levels in the hUC-MSCs group were higher than those in the other groups and highest in the hUC-MSCs+rhEPO group (all p<.01). CXCR-4 levels were also increased at P5 and highest at P14. hUC-MSCs+rhEPO might reduce nerve cell damage and improve neurobehavioral development, in connection with increased SDF-1 and CXCR-4 expression, in premature rats with WMD due to hypoxic-ischemic injury.

SDF-1 Improves Renal Fibrosis in Type 2 Diabetes Mellitus Involving TGF-beta-mediated ECM via PI3K/AKT Signaling

The present study investigated the role of stromal cell-derived factor-1 in the progression of renal injury in type 2 diabetic nephropathy. The 8-week old male db/db mice were used as the model of diabetic nephropathy and aged-matched male C57BL/6 mice constituted the control group. Fasting blood glucose, 24 hour urinary albumin and the creatinine clearance rate were measured. The expressions of stromal cell-derived factor-1, CXC chemokine receptor 4 and F4/80 were detected. Normal rat kidney epithelial cells were exposed to stromal cell-derived factor-1α, high glucose, tumor growth factor-β1, valsartan and LY294002, respectively. The extracellular matrix expression was evaluated. It was found that creatinine clearance rate was significantly decreased in 28-week db/db mice compared to the age-matched C57BL/6 mice and valsartan could significantly increase creatinine clearance rate. The expression of stromal cell-derived factor-1, CXC chemokine receptor 4 and F4/80 was significantly increased in the kidney of db/db mice but not in C57BL/6 mice, which was improved with valsartan treatment. In vitro, the expression of CXC chemokine receptor 4 was detected in the rat kidney epithelial cells. Tumor growth factor-β1 increased the expressions of type IV collagen and fibronectin in rat kidney epithelial cells under low glucose and high glucose condition. Stromal cell-derived factor-1α inhibited the harmful effect of tumor growth factor-β1 on extracellular matrix expression, and valsartan exerted synergistic effect on stromal cell-derived factor-1α. Stromal cell-derived factor-1α decreased tumor growth factor-β1expression and increased p-AKT expression, which were inhibited by LY294002 treatment. Stromal cell-derived factor-1 improved renal fibrosis which might partly involve TGF-β-mediated extracellular matrix via PI3K/AKT pathway.

Stromal cell-derived factor 1 (SDF-1) and its receptor CXCR4 improves diabetic retinopathy.

Diabetes induced a serious of complications including diabetic retinopathy. Our study aimed to investigate the role of Stromal cell-derived factor 1 (SDF-1) and its receptor CXCR4 in diabetic retinopathy. A mice model of diabetic retinopathy was established, and expression of SDF-1 and CXCR4 in retina was examined by Real-time quantitative PCR (qRT-PCR). Cells of human retinal pigment epithelial cell line ARPE-19 were treated with CXCR4 siRNAs and expression vector, and cell viability was detected by MTT assay. We found that expression of SDF-1 and CXCR4 in retina was significantly downregulated in mice with diabetic retinopathy than in normal healthy mice. High glucose treatment downregulated the expression of SDF-1 and CXCR4 in ARPE-19 cells at both mRNA and protein levels. Transfection with CXCR4 siRNAs decreased, while transfection with CXCR4 expression vector increased cell viability under high glucose treatment. We concluded that SDF-1/CXCR4 pathway improved diabetic retinopathy possibly by increasing cell viability. Abbreviations: SDF-1: Stromal cell-derived factor 1; CXCL12: C-X-C motif chemokine 12; qRT-PCR: Real-time quantitative PCR.

SDF-1/CXCR4 axis coordinates crosstalk between subchondral bone and articular cartilage in osteoarthritis pathogenesis.

Crosstalk between subchondral bone and articular cartilage is considered a central feature of osteoarthritis (OA) initiation and progression, but its underlying molecular mechanism remains elusive. Meanwhile, specific administration of drugs in subchondral bone is also a great challenge during investigation of the process. We here explore the role of stromal cell-derived factor 1 (SDF-1)/C-X-C chemokine receptor type 4 (CXCR4) axis in the crosstalk between subchondral bone and articular cartilage in OA pathogenesis, using osmotic infusion pumps implanted in tibial subchondral bone directly to ensure quantitative, continuous and steady drug delivery over the entire experiment. We found that increased SDF-1 in subchondral bone firstly induced subchondral bone deterioration by erroneous Mesenchymal Stem Cells (MSCs) recruitment and excessive bone resorption in anterior cruciate ligament transection (ACLT) mice. Deterioration of subchondral bone then led to the traverse of SDF-1 from subchondral bone to overlying cartilage. Finally, SDF-1 from underlying subchondral bone combined with CXCR4 in chondrocytes to induce articular cartilage degradation by promoting the shift of transforming growth factor-β receptor type I (TβRI) in chondrocytes from activin receptor-like kinase 5 (ALK5) to activin receptor-like kinase 1 (ALK1). More importantly, specific inhibition of SDF-1/CXCR4 axis in ACLT rats attenuated OA by stabilizing subchondral bone microarchitecture, reducing SDF-1 in cartilage and abrogating the shift of TβRI in chondrocytes. Our data demonstrate that the SDF-1/CXCR4 axis may coordinate the crosstalk between subchondral bone and articular cartilage in OA pathogenesis. Therefore, specific inhibition of SDF-1/CXCR4 axis in subchondral bone or intervention in SDF-1 traverse may be therapeutic targets for OA.

Role of SDF-1:CXCR4 in Impaired Post-Myocardial Infarction Cardiac Repair in Diabetes.

Diabetes is a risk factor for worse outcomes following acute myocardial infarction (AMI). In this study, we tested the hypothesis that SDF‐1:CXCR4 expression is compromised in post‐AMI in diabetes, and that reversal of this defect can reverse the adverse effects of diabetes. Mesenchymal stem cells (MSC) isolated from green fluorescent protein (GFP) transgenic mice (control MSC) were induced to overexpress stromal cell‐derived factor‐1 (SDF‐1). SDF‐1 expression in control MSC and SDF‐1‐overexpressing MSC (SDF‐1:MSC) were quantified using enzyme‐linked immunosorbent assay (ELISA). AMI was induced on db/db and control mice. Mice were randomly selected to receive infusion of control MSC, SDF‐1:MSC, or saline into the border zone after AMI. Serial echocardiography was used to assess cardiac function. SDF‐1 and CXCR4 mRNA expression in the infarct zone of db/db mice and control mice were quantified. Compared to control mice, SDF‐1 levels were decreased 82%, 91%, and 45% at baseline, 1 day and 3 days post‐AMI in db/db mice, respectively. CXCR4 levels are increased 233% at baseline and 54% 5 days post‐AMI in db/db mice. Administration of control MSC led to a significant improvement in ejection fraction (EF) in control mice but not in db/db mice 21 days after AMI. In contrast, administration of SDF‐1:MSC produced a significant improvement in EF in both control mice and db/db mice 21 days after AMI. The SDF‐1:CXCR4 axis is compromised in diabetes, which appears to augment the deleterious consequences of AMI. Over‐express of SDF‐1 expression in diabetes rescues cardiac function post AMI. Our results suggest that modulation of SDF‐1 may improve post‐AMI cardiac repair in diabetes. stem cells translational medicine 2018;7:115–124

Relationship between rs1801157 polymorphism in stromal cell-derived factor gene and systemic lupus erythematosus risk.

ObjectivePresent meta-analysis was performed to investigate the role of stromal cell-derived factor (SDF-1) gene rs1801157 polymorphism in systemic lupus erythematosus (SLE).ResultsFive publications with 1,087 cases and 1,181 controls were incorporated in this meta-analysis. Overall, a marginal association between SDF-1 rs1801157 polymorphism and reduced SLE risk was found under GA vs. GG model (OR = 0.84, 95% CI = 0.70–1.00). A similar result was also observed in Asian subgroup under the same comparison after stratification analysis by ethnicity (OR = 0.79, 95% CI = 0.63–1.00).Materials and MethodsAll included studies were retrieved from PubMed, EMBASE, Google Scholar Web and Chinese National Knowledge Infrastructure (CNKI). Odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated to appraise the strength of association between SDF-1 rs1801157 polymorphism and SLE risk. The stratification analysis was also performed according to ethnicity. In addition, heterogeneity was examined with Q test, and sensitivity analysis was used to test the stability of final results. Begg’s funnel plot and Egger’s test were adopted to evaluate publication bias.ConclusionsSDF-1 rs1801157 polymorphism may not influence the risk of SLE. However, more studies with larger sample sizes involving different populations are needed to further explore this issue.

Role of SDF-1/CXCR4 axis in the invasion and migration of human choriocarcinoma cells and its significance in preeclampsia

Objective To investigate the effects of stromal cell-derived factor 1 (SDF-1) and an CXC chemokine receptor 4 (CXCR4) antagonist (AMD3100) on the invasion and migration capabilities of the huaman choriocarcinoma cell line JAR for further elucidating the role of SDF-1/CXCR4 axis in the pathogenesis of preeclampsia. Methods JAR cells were divided into four groups: SDF-1 group (treated with 50 ng/ml of SDF-1), SDF-1+ AM3100 mixed group (first treated with 100 ng/ml of AMD3100 for 2 hours and then treated with 50 ng/ml of SDF-1), AMD3100 group (treated with 100 ng/ml of AMD3100) and blank control group (without any treatment). RT-PCR was performed to detect the expression of CXCR4 at mRNA level in JAR cells. Western blot assay was used to measure the expression of CXCR4 and p-AKT at protein level. MTT assay was used to analyze the effects of different concentrations of SDF-1 (10, 30, 50 and 100 ng/ml) on the proliferation of JAR cells at different time points (0, 24, 48, 72 h). Transwell invasion assay and wound-healing assay were used to test the changes in invasion and migration capabilities of JAR cells after different treatments. Results (1) Results of the RT-PCR showed that the expression of CXCR4 at mRNA level in JAR cells was increased in the SDF-1 group (1.839±0.083) as compared with that in the blank control group (1.372±0.086), AMD3100 group (0.694±0.045) or SDF-1+ AM3100 mixed group (0.703±0.093). Moreover, the differences between the SDF-1 group and the other three groups were statistically significant (F=30.67, P<0.05). Compared with the blank control group, the expression of CXCR4 at mRNA level in JAR cells was decreased in the AMD3100 group (P<0.01). (2) Results of the Western blot assay showed that the expression of CXCR4 and p-AKT at protein level in JAR cells were enhanced in the SDF-1 group as compared with that in the blank control group, AMD3100 group or SDF-1+ AM3100 mixed group. Compared with the blank control group, the expression of CXCR4 and p-AKT at protein level in JAR cells were inhibited in the AMD3100 group. (3) Results of the MTT assay showed that SDF-1, especially at the concentration of 50 ng/ml, could enhance the proliferation of JAR cells (P<0.05) and its best effect on proliferation was seen at 48 h. (4) Results of the Transwell invasion assay showed that the number of transmembrane cells in the SDF-1 group (70.49±2.42) was more than that in the blank control group (54.36±2.26), AMD3100 group (21.68±8.31), or SDF-1+ AMD3100 mixed group (28.18±4.61). The differences between the SDF-1 group and the other three groups were statistically significant (F=116.26, P<0.01). Compared with the blank control group, the number of transmembrane cells was reduced in the AMD3100 group (P<0.05). (5) Results of the wound-healing assay showed that the relative migration distance was increased in the SDF-1 group (1.162±0.034) as compared with that in the blank control group (0.823±0.101), AMD3100 group (0.160±0.047), or SDF-1+ AMD3100 mixed group (0.183±0.064). The differences between the SDF-1 group and the other three groups were statistically significant (F=30.500, P<0.05). Compared with the blank control group, the relative migration distance was decreased in the AMD3100 group (P<0.01). Conclusion The invasion and migration of huaman choriocarcinoma JAR cells can be enhanced by SDF-1, but inhibited by AMD3100. This study indicates that the blocked biological axis of SDF-1/CXCR4 may play an important role in the pathogenesis of preeclampsia through inducing abnormal activation of PI3K/AKT pathway, which results in inhibited invasion and migration of trophoblast cells and placenta abnormality. Key words: SDF-1/CXCR4 axis; Invasion; Migration; PI3K/AKT pathway; Trophoblast cell; Preeclampsia

CXCR7 as a chemokine receptor for SDF-1 promotes gastric cancer progression via MAPK pathways

Objective: As the alternate receptor for stromal cell-derived factor-1 (SDF-1) except CXCR4, CXCR7 has been shown to be involved in the progression of some malignancies. However, the role of SDF-1/CXCR7 in gastric cancer (GC) remains unclear.Materials and methods: CXCR7 expression was examined in 83 human GC tissues and adjacent non-cancer tissues (ANCTs) by immunohistochemistry, in three human GC cell lines (MGC-803, BGC-823 and SGC-7901) by reverse transcription-PCR and western blot. CXCR7 was stably knocked down via lentiviral vectors. The cells proliferation was evaluated using CCK-8 and colony formation assay; MAPK pathways (ERK1/2, p38 and SAPK/JNK) were detected using western blot. Besides, the xenograft model of nude mice for GC growth was performed.Results: CXCR7 expression in GC tissues was significantly higher than that in ANCTs and associated with tumor size, TNM stage and lymph node metastasis. CXCR7 and CXCR4 were both detectable in three GC cell lines and SGC-7901 cells expressed CXCR7 the most abundantly. SDF-1 promoted the proliferation of SGC-7901 cells, the phosphorylation of ERK1/2, p38 and CXCR7 knockdown distinctly reversed these changes; the proliferation stimulated with SDF-1 was attenuated by U0126 (MEK1/2 inhibitor). Furthermore, CXCR7 knockdown inhibited the growth of GC subcutaneous xenografts and decreased the microvessel density and VEGF expression in vivo.Conclusion: CXCR7 was identified as a novel promoter in GC initiation and progression.

Attenuation of subchondral bone abnormal changes in osteoarthritis by inhibition of SDF-1 signaling.

Current conservative treatments for osteoarthritis (OA) are largely symptoms control therapies. Further understanding on the pathological mechanisms of OA is crucial for new pharmacological intervention. In this study, we investigated the role of Stromal cell-derived factor-1(SDF-1) in regulating subchondral bone changes during the progression of OA. Clinical samples of different stages of OA severity were analyzed by histology staining, micro-CT, enzyme-linked immunosorbent assay (ELISA) and western blotting, to compare SDF-1 level in subchondral bone. The effects of SDF-1 on human mesenchymal stem cells (MSCs) osteogenic differentiation were evaluated. Invivo assessment was performed in an anterior cruciate ligament transaction plus medial meniscus resection in the SD rats. The OA rats received continuous infusion of AMD3100 (SDF-1 receptor blocker) in osmotic mini-pump implanted subcutaneously for 6 weeks. These rats were then terminated and subjected to the same invitro assessments as human OA samples. SDF-1 level was significantly elevated in the subchondral bone of human OA samples. In the cell studies, the results showed SDF-1 plays an important role in osteogenic differentiation of MSCs. In the OA animal studies, there were less cartilage damage in the AMD3100-treated group; microCT results showed that the subchondral bone formation was significantly reduced and so did the number of positive Nestin or Osterix cells in the subchondral bone region. Higher level of SDF-1 may induce the subchondral bone abnormal changes in OA and inhibition of SDF-1 signaling could be a potential therapeutic approach for OA.

Angiogenic Capacity of Dental Pulp Stem Cell Regulated by SDF-1α-CXCR4 Axis.

Previously, the perivascular characteristics of dental pulp stem cells (DPSCs) were reported, which suggested the potential application of DPSCs as perivascular cell source. In this study, we investigated whether DPSCs had angiogenic capacity by coinjection with human umbilical vein endothelial cells (HUVECs) in vivo; in addition, we determined the role of stromal cell-derived factor 1-α (SDF-1α) and C-X-C chemokine receptor type 4 (CXCR4) axis in the mutual interaction between DPSCs and HUVECs. Primarily isolated DPSCs showed mesenchymal stem cell- (MSC-) like characteristics. Moreover, DPSCs expressed perivascular markers such as NG2, α-smooth muscle actin (α-SMA), platelet-derived growth factor receptor β (PDGFRβ), and CD146. In vivo angiogenic capacity of DPSCs was demonstrated by in vivo Matrigel plug assay. We could observe microvessel-like structures in the coinjection of DPSCs and HUVECs at 7 days postinjection. To block SDF-1α and CXCR4 axis between DPSCs and HUVECs, AMD3100, a CXCR4 antagonist, was added into Matrigel plug. No significant microvessel-like structures were observed at 7 days postinjection. In conclusion, DPSCs have perivascular characteristics that contribute to in vivo angiogenesis. The findings of this study have potential applications in neovascularization of engineered tissues and vascular diseases.

Stromal cell–derived factor-1 is upregulated by dipeptidyl peptidase-4 inhibition and has protective roles in progressive diabetic nephropathy

The role of stromal cell-derived factor-1 (SDF-1) in the pathogenesis of diabetic nephropathy and its modification by dipeptidyl peptidase-4 (DPP-4) inhibition are uncertain. Therefore, we studied this independent of glucagon-like peptide-1 receptor (GLP-1R) signaling using two Akita diabetic mouse models, the diabetic-resistant C57BL/6-Akita and diabetic-prone KK/Ta-Akita. Increased SDF-1 expression was found in glomerular podocytes and distal nephrons in the diabetic-prone mice, but not in kidneys from diabetic-resistant mice. The DPP-4 inhibitor linagliptin, but not the GLP-1R agonist liraglutide, further augmented renal SDF-1 expression in both Glp1r(+/+) and Glp1r(-/-) diabetic-prone mice. Along with upregulation of renal SDF-1 expression, the progression of albuminuria, glomerulosclerosis, periglomerular fibrosis, podocyte loss, and renal oxidative stress was suppressed in linagliptin-treated Glp1r(+/+) diabetic-prone mice. Linagliptin treatment increased urinary sodium excretion and attenuated the increase in glomerular filtration rate which reflects glomerular hypertension and hyperfiltration. In contrast, selective SDF-1 receptor blockade with AMD3100 reduced urinary sodium excretion and aggravated glomerular hypertension in the Glp1r(+/+) diabetic-prone mice. Thus, DPP-4 inhibition, independent of GLP-1R signaling, contributes to protection of the diabetic kidney through SDF-1-dependent antioxidative and antifibrotic effects and amelioration of adverse renal hemodynamics.

Dipeptidyl peptidase-4 inhibition improves cardiac function in experimental myocardial infarction: Role of stromal cell-derived factor-1α.

In addition to degrading glucagon-like peptide-1 (GLP-1), dipeptidyl peptidase-4 (DPP-4) inactivates several chemokines, including stromal cell-derived factor-1α (SDF-1α), a pro-angiogenic and cardiomyocyte protective protein. We hypothesized that DPP-4 inhibition may confer benefit following myocardial infarction (MI) in the diabetic setting as a consequence of enhanced SDF-1α availability rather than potentiating GLP-1. To test this we compared the effects of saxagliptin with those of liraglutide and used the SDF-1α receptor (CXCR4) antagonist plerixafor. Studies were conducted in streptozotocin-diabetic rats. Rats were randomized to receive saxagliptin (10 mg/kg per day), liraglutide (0.2 mg/kg, s.c., b.i.d.), plerixafor (1 mg/kg per day, s.c.), saxagliptin plus plerixafor or vehicle (1% phosphate-buffered saline). Two weeks later, rats underwent experimental MI, with cardiac function examined 4 weeks after MI. Glycemic control and MI size were similar in all groups. Four weeks after MI, mortality was reduced in saxagliptin-treated rats compared with vehicle treatment (P < 0.05). Furthermore, rats receiving saxagliptin had improved cardiac function compared with vehicle-treated rats (P < 0.05). Antagonism of CXCR4 prevented the improvement in cardiac function in saxagliptin-treated rats and was associated with increased mortality (P < 0.05). Saxagliptin-mediated DPP-4 inhibition, but not liraglutide-mediated GLP-1R agonism, improved cardiac function after MI independent of glucose lowering. These findings suggest that non-GLP-1 actions of DPP-4 inhibition, such as SDF-1α potentiation, mediate biological effects.

CXC chemokine receptor-4 signaling limits hepatocyte proliferation after hepatic ischemia-reperfusion in mice.

The role of stromal cell-derived factor-1 (SDF-1 or CXCL12) and its receptor CXC chemokine receptor-4 (CXCR4) in ischemic liver injury and recovery has not been studied. Some reports suggest that this chemokine may aid in liver regeneration, but others suggest that it may be profibrotic through its activation of hepatic stellate cells. In this study we sought to elucidate the role of SDF-1 and its receptor CXCR4 during liver injury, recovery, and regeneration after ischemia-reperfusion (I/R). A murine model of partial (70%) I/R was used to induce liver injury and study the reparative and regenerative response. CXCR4 was expressed constitutively in the liver, and hepatic levels of SDF-1 peaked 8 h after reperfusion but remained significantly increased for 96 h. Treatment of mice with the CXCR4 antagonist AMD3100 or agonist SDF-1 had no effect on acute liver injury assessed 8 h after I/R. However, treatment with AMD3100 increased hepatocyte proliferation after 72 and 96 h of reperfusion and reduced the amount of liver necrosis. In contrast, treatment with SDF-1 significantly decreased hepatocyte proliferation. These effects appeared to be dependent on the presence of liver injury, as AMD3100 and SDF-1 had no effect on hepatocyte proliferation or liver mass in mice undergoing 70% partial hepatectomy. The data suggest that signaling through CXCR4 is detrimental to liver recovery and regeneration after I/R and that clinical therapy with a CXCR4 antagonist may improve hepatic recovery following acute liver injury.

The role of SDF-1/CXCR4 on airway inflammation and airway remodeling in a rat asthma model

To explore the roles of stromal cell-derived factor 1 (SDF-1) and C-X-C chemokine receptor 4 (CXCR4) on airway inflammation and airway remodeling in rat asthma models. Eighteen female SD rats were randomly divided into 3 groups (n = 6): control group, asthmatic 4 weeks group and asthmatic 8 weeks group. The rats were sensitized and inhaled ovalbumin (OVA). After the asthma model was successfully established, the airway pressure was measured. The methods of HE staining and Image-Pro Plus image analysis software were used to detect the changes of eosinophils (EOS), the perimeter of inner bronchial lumen, the wall area, the area of bronchial smooth muscle and the number of smooth muscle cells of airway walls. RT-PCR and Western-blot were used to detect the expression of SDF-1 and CXCR4 in lung tissues among the 3 groups.Immunohistochemistry was used to detect the expression of SDF-1 in airway walls. Compared with the control group, the airway responsiveness, the count of EOS, the area of bronchial wall, the area of bronchial smooth muscle, the number of smooth muscle cells of airway walls in the asthmatic 4 weeks and asthmatic 8 weeks were significantly increased, and significant difference between the 2 asthmatic groups was also observed in the above indexes (P < 0.01) .RT-PCR showed that compared with the control group (SDF-1 was 0.146 ± 0.003 and CXCR4 was 0.281 ± 0.002) , the expression of SDF-1 (0.583 ± 0.004 and 0.724 ± 0.008) and CXCR4 (0.467 ± 0.003 and 0.655 ± 0.002) in lung tissues in the asthmatic 4 weeks and asthmatic 8 weeks were significantly increased (P < 0.01) . In addition, compared with the asthmatic 4 weeks group, the expression of SDF-1 and CXCR4 in lung tissues in the 8 weeks asthmatic group were significantly increased (P < 0.01) . Compared with the control group (0.180 ± 0.009) , the expression of SDF-1 in airway walls in the asthmatic 4 weeks and asthmatic 8 weeks groups (0.270 ± 0.006 and 0.350 ± 0.009) were significantly increased (P < 0.01) . In addition, compared with the asthmatic 4 weeks group, the expression of SDF-1 in airway walls in the 8 weeks asthmatic group was significantly increased (P < 0.01) . The expression of SDF-1 and CXCR4 was correlated positively with the airway responsiveness, the number of EOS, the area of bronchial wall, the area of bronchial smooth muscle and the number of smooth muscle cells of airway walls (P < 0.01). SDF-1/CXCR4 axis may play a key role in airway inflammation and airway remodeling of asthma.

Low intensity pulsed ultrasound enhanced mesenchymal stem cell recruitment through stromal derived factor-1 signaling in fracture healing.

Low intensity pulsed ultrasound (LIPUS) has been proven effective in promoting fracture healing but the underlying mechanisms are not fully depicted. We examined the effect of LIPUS on the recruitment of mesenchymal stem cells (MSCs) and the pivotal role of stromal cell-derived factor-1/C-X-C chemokine receptor type 4 (SDF-1/CXCR4) pathway in response to LIPUS stimulation, which are essential factors in bone fracture healing. For in vitro study, isolated rat MSCs were divided into control or LIPUS group. LIPUS treatment was given 20 minutes/day at 37°C for 3 days. Control group received sham LIPUS treatment. After treatment, intracellular CXCR4 mRNA, SDF-1 mRNA and secreted SDF-1 protein levels were quantified, and MSCs migration was evaluated with or without blocking SDF-1/CXCR4 pathway by AMD3100. For in vivo study, fractured 8-week-old young rats received intracardiac administration of MSCs were assigned to LIPUS treatment, LIPUS+AMD3100 treatment or vehicle control group. The migration of transplanted MSC to the fracture site was investigated by ex vivo fluorescent imaging. SDF-1 protein levels at fracture site and in serum were examined. Fracture healing parameters, including callus morphology, micro-architecture of the callus and biomechanical properties of the healing bone were investigated. The in vitro results showed that LIPUS upregulated SDF-1 and CXCR4 expressions in MSCs, and elevated SDF-1 protein level in the conditioned medium. MSCs migration was promoted by LIPUS and partially inhibited by AMD3100. In vivo study demonstrated that LIPUS promoted MSCs migration to the fracture site, which was associated with an increase of local and serum SDF-1 level, the changes in callus formation, and the improvement of callus microarchitecture and mechanical properties; whereas the blockade of SDF-1/CXCR4 signaling attenuated the LIPUS effects on the fractured bones. These results suggested SDF-1 mediated MSCs migration might be one of the crucial mechanisms through which LIPUS exerted influence on fracture healing.