Expression Of Stromal Cell-derived Factor-1α Research Articles

Neurotrophin-3 accelerates reendothelialization through inducing EPC mobilization and homing.

Rapid endothelialization is an effective way to treat intimal hyperplasia after intravascular stent implantation. Blood vessels and nerves coordinate with each other in function, while neurotrophin-3 (NT-3) is an important class of nerve growth factors. Our study found that NT-3 promoted endothelial progenitor cell (EPC) mobilization, and the proportion of EPCs in peripheral blood was increased by 1.774 times compared with the control group. Besides, NT-3 promoted the expression of stromal cell-derived factor-1α (SDF-1α), matrix metalloproteinase-9 (MMP9), and chemokine (C-X-C motif) receptor 4 (CXCR4) in EPCs, which increased by 59.89%, 74.46%, and 107.7%, respectively, compared with the control group. Transwell experiments showed that NT-3 enhanced the migration of EPCs by 1.31 times. Flow chamber experiments demonstrated that NT-3 captured more circulating EPCs. As shown by ELISA results, NT-3 can promote the paracrine of vascular endothelial growth factor, interleukin-8, MMP-9, and SDF-1 from EPCs. Such increased angiogenic growth factors further accelerated the closure of endothelial cell scratches. Additionally, EPC-conditioned medium in the NT-3 group significantly inhibited the proliferation of vascular smooth muscle cells. Then animal experiments also illustrated that NT-3 prominently accelerated the endothelialization of injured carotid artery. In short, NT-3 accelerated rapid reendothelialization of injured carotid artery through promoting EPC mobilization and homing.

Novel repair mechanisms in a renal ischaemia/reperfusion model: Subsequent saxagliptin treatment modulates the pro-angiogenic GLP-1/cAMP/VEGF, ANP/eNOS/NO, SDF-1α/CXCR4, and Kim-1/STAT3/HIF-1α/VEGF/eNOS pathways

The reno-protective effects of antidiabetic dipeptidyl peptidase (DPP)-4 inhibitors have been studied regarding their antioxidant and anti-inflammatory properties. However, the potential ability of saxagliptin to ameliorate renal injury by enhancing neovascularization has not been elucidated. To address this issue, saxagliptin (10 and 30 mg/kg) was administered to Wistar rats after the induction of renal ischaemia/reperfusion (I/R). Our results showed that saxagliptin operated through different axes to ameliorate I/R injury. By inhibiting DPP-4, saxagliptin maintained stromal cell-derived factor-1α expression and upregulated its chemokine receptor CXCR4 to trigger vasculogenesis through the enhanced migration of endothelial progenitor cells (EPCs). Additionally, this compound rescued the levels of glucagon-like peptide-1 and its downstream mediator cAMP to increase vascular endothelial growth factor (VEGF) and CXCR4 levels. Moreover, saxagliptin stimulated atrial natriuretic peptide/endothelial nitric oxide synthase to increase nitric oxide levels and provoke angiogenesis and renal vasodilation. In addition to inhibiting DPP-4, saxagliptin increased the renal kidney injury molecule-1/pY705-STAT3/hypoxia-inducible factor-1α/VEGF pathway to enhance angiogenesis. Similar to other gliptins, saxagliptin exerted its anti-inflammatory and antioxidant effects by suppressing the renal contents of p (S536)-nuclear factor-κB p65, tumour necrosis factor-α, monocyte chemoattractant protein-1, myeloperoxidase, and malondialdehyde while boosting the glutathione content. These events improved the histological structure and function of the kidney, as evidenced by decreased serum creatinine, blood urea nitrogen, and cystatin C and increased serum albumin. Accordingly, in addition to its anti-inflammatory and antioxidant activities, saxagliptin dose-dependently ameliorated I/R-induced renal damage by enhancing neovascularization through improved tissue perfusion and homing of bone marrow-derived EPCs to mediate repair processes.

Effects of bone marrow mesenchymal stem cell transplantation on the expression of stromal cell-derived factor-1α and vascular endothelial growth factor in rats with acute hepatic failure

Objective: To investigate the curative effect of bone marrow mesenchymal stem cells (BMSCs) transplantation on the expression of stromal cell-derived growth factor (SDF-1 α) and vascular endothelial growth factor (VEGF) in rats with acute hepatic failure, and to compare the effects of two transplantation pathways. Methods: Eighty-four rats with acute liver failure (ALF) induced by D-galactosamine combined with lipopolysaccharide were randomly divided into control group, tail vein and portal vein transplantation group. The latter two groups were injected allogenic BMSCs into the tail vein and portal vein. Blood samples and liver tissue samples were collected at 24, 72, 120, and 168h after transplantation to detect serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The improvement of liver function before and after BMSCs transplantation was compared. The expression of VEGF and SDF-1a in liver tissue was detected by immunofluorescence and Western blot. Data measurement between two groups was performed by analysis of variance and the correlation analysis was performed by Spearman's rank correlation coefficient. Results: Serum ALT and AST levels in the tail vein and portal vein transplantation group peaked at 24 h after transplantation, which were (134.60 ± 58.08 IU/L), (179.20 ± 86.68 IU/L), and (131.00 ± 54.47 IU/L), (173.50 ± 93.10 IU/L). In addition, 168h after transplantation it decreased to (46.10 ± 8.40 IU/L), (95.67 ± 13.80 IU/L) and (19.30 ± 1.30 IU/L), (54.30 ± 6.00 IU/L). After 120 and 168 hours of BMSCs transplantation, the levels of serum ALT and AST in tail vein and portal vein transplantation group were significantly higher than control group (F ≥ 12.51, P < 0.01). The results of western blot and immunofluorescence showed that the expression levels of SDF-1α and VEGF protein in the two BMSCs transplantation groups increased with the improvement of liver function, and the difference was statistically significant at 120 and 168 hours after transplantation (F ≥ 9.069, P < 0.05). There was no significant difference in the expression of SDF-1a and VEGF between the tail vein and portal vein transplantation groups (P > 0.05). Correlation analysis showed that the expression levels of SDF-1α and VEGF in liver tissues were positively correlated (r = 0.923, P < 0.05). Conclusion: BMSCs transplantation can promote the secretion of VEGF for recovery of liver function to reduce the degree of inflammation and necrosis in rats with ALF.

Immunological effects of a low-dose cytarabine, aclarubicin and granulocyte-colony stimulating factor priming regimen on a mouse leukemia model.

The low-dose cytarabine, aclarubicin and granulocyte-colony stimulating factor (G-CSF) (CAG) priming regimen is an effective treatment for patients with relapsed or refractory acute myeloid leukemia (AML) and advanced myelodysplastic syndrome (MDS). G-CSF influences the bone marrow microenvironment (BMM) by mobilizing regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs), as well as by reducing the expression of stromal cell-derived factor-1α (SDF-1α). In the present study, a WEHI-3-grafted BALB/c mouse AML model (AML-M4) was employed to determine how the BMM was altered by different treatment regimens. It was evident that CAG regimen decreased and increased the proportion of Tregs and MDSCs in the bone marrow and spleen, respectively. Furthermore, the CAG regimen downregulated SDF-1α levels in the bone marrow and peripheral blood. However, hematoxylin and eosin staining of the main organs revealed that leukemic cells infiltrated the liver following treatment with the CAG regimen. The present study indicates that the CAG regimen has a positive effect on the immunosuppressive microenvironment in AML and relieves AML-associated BMM immune suppression by decreasing Tregs and MDSCs in the bone marrow and downregulating the SDF-1α/CXCR4 axis in the bone marrow and peripheral blood.

Effects of conditioned medium from LL-37 treated adipose stem cells on human fibroblast migration.

Adipose stem cell-conditioned medium may promote human dermal fibroblast (HDF) proliferation and migration by activating paracrine peptides during the re-epithelization phase of wound healing. Human antimicrobial peptide LL-37 is upregulated in the skin epithelium as part of the normal response to injury. The effects of conditioned medium (CM) from LL-37 treated adipose stem cells (ASCs) on cutaneous wound healing, including the mediation of fibroblast migration, remain to be elucidated, therefore the aim of the present study was to determine how ASCs would react to an LL-37-rich microenvironment and if CM from LL-37 treated ASCs may influence the migration of HDFs. The present study conducted migration assays with HDFs treated with CM from LL-37 treated ASCs. Expression of CXC chemokine receptor 4 (CXCR4), which controls the recruitment of HDFs, was analyzed at the mRNA and protein levels. To further characterize the stimulatory effects of LL-37 on ASCs, the expression of stromal cell-derived factor-1α (SDF-1α), a CXC chemokine, was investigated. CM from LL-37-treated ASCs induced migration of HDFs in a time- and dose-dependent manner, with a maximum difference in migration observed 24 h following stimulation with LL-37 at a concentration of 10 µg/ml. The HDF migration and the expression of CXCR4 in fibroblasts was markedly increased upon treatment with CM from LL-37-treated ASCs compared with CM from untreated ASCs. SDF-1α expression was markedly increased in CM from LL-37 treated ASCs. It was additionally observed that SDF-1α blockade significantly reduced HDF migration. These findings suggest the feasibility of CM from LL-37-treated ASCs as a potential therapeutic for human dermal fibroblast migration.

Immunological effects of vaccines combined with granulocyte colony-stimulating factor on a murine WEHI-3 leukemia model.

Granulocyte colony-stimulating factor (G-CSF) mobilizes regulatory T cells (Tregs) from bone marrow into the peripheral blood, by reducing the expression of stromal cell-derived factor-1α (SDF-1α). However, G-CSF has rarely been studied in acute myeloid leukemia (AML) immunotherapy. The present study performed a Transwell migration assay in vitro to determine the contribution of SDF-1α to the migration of leukemia cells, and the effects of G-CSF were evaluated. The effects of G-CSF on SDF-1α and Tregs in the AML microenvironment were examined, by employing a WEHI-3-grafted BALB/c mouse AML model (AML-M4). It is evident that G-CSF reversed immunosuppression of the AML microenvironment by reducing SDF-1α in bone marrow and elevating Tregs in the peripheral blood in in vivo studies. Furthermore, AML mice treated with vaccines combined with G-CSF achieved a longer survival time than those treated with vaccines without G-CSF, showing the efficiency of the regimen. The present study demonstrates the effects of G-CSF on the mobilization of leukemia cells and Tregs into the peripheral blood. In addition, immunotherapy with G-CSF priming represents a promising therapeutic strategy of targeting the immunosuppression.

High mobility group box 1-immobilized nanofibrous scaffold enhances vascularization, osteogenesis and stem cell recruitment.

Most tissue engineered bone scaffolds are limited by insufficient vascularization. In this study, a high mobility group box 1 (HMGB1)-immobilized material for in situ tissue engineering was prepared to facilitate bone regeneration. The HMGB1-immobilized scaffold accelerated the adhesion and osteogenic differentiation of mesenchymal stem cells (MSCs) in vitro. Subcutaneous implantation and rat calvarial defect repair experiments proved that the HMGB1-immobilized scaffold induced vascularization and enhanced expression of osteocalcin in vivo. MSCs were recruited into the scaffold, which might due to the high expression of stromal cell-derived factor-1α. The bone repair efficiency of the HMGB1-immobilized scaffold was significantly superior to and faster than that of the poly-l-lactide/polycaprolactone nanofibrous scaffold. This research demonstrated the feasibility of using only one pro-inflammatory cytokine HMGB1 as a 'trigger' signal in bone tissue engineering to simultaneously realize multiple functions, including enhancing vascularization, inducing osteogenesis and recruiting stem cells. Consequently, the bone regeneration process was accelerated. The results are of great significance for preparing a new type of scaffold that can promote bone repair in multiple aspects by mimicking a natural manner.

Recruitment of mesenchymal stem cells by stromal cell-derived factor 1α in pulp cells from deciduous teeth.

Dental pulp cells (DPCs), including dental pulp (DP) stem cells, play a role in dentine repair under certain conditions caused by bacterial infections associated with caries, tooth fracture and injury. Mesenchymal stem cells (MSCs) have also been shown to be involved in this process of repair. However, the mechanisms through which MSCs are recruited to the DP have not yet been elucidated. Therefore, the aim of the present in vitro study was to investigate whether stromal cell-derived factor 1α (SDF1)-C-X-C chemokine receptor type 4 (CXCR4) signaling is involved in tissue repair in the DP of deciduous teeth. A single-cell clone from DPCs (SDP11) and UE7T-13 cells were used as pulp cells and MSCs, respectively. The MG-63 and HuO9 cells, two osteosarcoma cell lines, were used as positive control cells. Reverse transcription polymerase chain reaction (RT-PCR) revealed that all cell lines (SDP11, UE7T-13 MG-63 and HuO9) were positive for both SDF1 and CXCR4 mRNA expression. Moreover, immunocytochemical analysis indicated that SDF1 and CXCR4 proteins were expressed in the SDP11 and UE7T-13 cells. SDF1 was also detected in the cell lysates (CLs) and conditioned medium (CM) collected from the SDP11 and UE7T-13 cells, and AMD3100, a specific antagonist of CXCR4, inhibited the migration of the UE7T-13 cells; this migration was induced by treatment with CM, which was collected from the SDP11 cells. In addition, real-time PCR showed that the expression of SDF1 in the SDP11 cells was inhibited by treatment with 20 ng/ml fibroblast growth factor (FGF)-2, and exposure to AZD4547, an inhibitor of the FGF receptor, blocked this inhibition. Collectively, these data suggest that SDF1 produced by DP plays an important role in homeostasis, repair and regeneration via the recruitment of MSCs.

Relationship between expression of stromal cell-derived factor-1α and lymph node metastasis in early gastric cancer

Relationship between expression of stromal cell-derived factor-1α and lymph node metastasis in early gastric cancer

Upregulation of stromal cell-derived factor 1α expression is associated with the resistance to neoadjuvant chemoradiotherapy of locally advanced rectal cancer: angiogenic markers of neoadjuvant chemoradiation.

The ability to achieve pathologic downstaging after neoadjuvant chemoradiotherapy (NCRT) is correlated with improved survival in locally advanced rectal cancer (LARC). However, there is no effective predictive markers. In this study, the expression of angiogenic markers was evaluated in pre-treatment biopsies and corresponding post-treatment resection specimens, and were correlated to histopathological tumour characteristics and response. Fifty-five patients with stage II/III rectal cancer treated with 5-fluorouracil (5-FU)-based NCRT were studied. All patients were administered NCRT followed by surgical resection. Immunohistochemical staining for angiogenic markers [hypoxia-inducible factor 1α (HIF‑1α), vascular endothelial growth factor (VEGF), stromal cell‑derived factor 1α (SDF-1α) and placental growth factor (PlGF)] was performed on specimens obtained before NCRT and after surgery. Expression of VEGF, PlGF and HIF-1α protein was downregulated after NCRT in the rectal cancer tissues (P<0.001, P=0.001 and P=0.044, respectively). However, SDF-1α was upregulated after NCRT (P<0.001). Moreover, upregulated expression of SDF-1α (P=0.016) and positive PlGF staining (P=0.001) after NCRT were significantly associated with resistance to NCRT. On multivariate analysis, positive PlGF staining after NCRT was found to be independently associated with resistance to NCRT (P=0.013). Our data suggest that SDF-1α and PlGF should be evaluated as new targets for NCRT in LARC.

Postacute stromal cell-derived factor-1α expression promotes neurovascular recovery in ischemic mice.

Acute interventions of stroke are often challenged by a narrow treatment window. In this study, we explore treatments in the postacute phase of stroke with wider windows of opportunity. We investigated the effects of stromal cell-derived factor (SDF-1α) in neurovascular recovery during the postacute phase and downstream signaling pathways, underlying SDF-1α-mediated neurovascular recovery. Adult male Institute of Cancer Research (ICR) mice underwent middle cerebral artery occlusion. One week after middle cerebral artery occlusion, the animals received stereotactic injection of adenoassociated virus (AAV) carrying SDF-1α gene as treatment or AAV-green fluorescent protein as control and were monitored for 5 weeks. Neurobehavioral outcomes were evaluated, and brain atrophy was measured. Neurogenesis and angiogenesis were examined. The proliferation and migration of neural progenitor cells were evaluated. Downstream pathways of SDF-1α were investigated. Inflammatory response was monitored. Neurobehavioral outcomes were improved, and brain atrophy was greatly reduced for ≤5 weeks in AAV-SDF-1α groups when compared with the control. SDF-1 receptor CXCR4 was upregulated and colocalized with neural and endothelial progenitor cells. The number of nestin(+) and doublecortin(+)/bromodeoxyuridine(+) cells in the subventricular zone, doublecortin(+) and neuron(+)/bromodeoxyuridine(+) cells in the perifocal region, and cluster of differentiation (CD)31(+) and bromodeoxyuridine(+)/CD31(+) microvessels are also significantly increased in AAV-SDF-1α groups. Administration of CXCR4 antagonist AMD3100 eliminated the beneficial effects of SDF-1α. SDF-1α/CXCR4 interaction activated AKT, extracellular signal-regulated kinases (ERK), and P38 mitogen-activated protein kinase (MAPK) signaling pathways but not the c-Jun N-terminal kinase (JNK) pathway. SDF-1α promoted neurogenesis and angiogenesis during the postacute phase of ischemia without eliciting an inflammatory response. AAV-SDF-1α expression represents a promising avenue for ischemic stroke therapy with a wider treatment window.

SDF-1/CXCR4 Signaling Preserves Microvascular Integrity and Renal Function in Chronic Kidney Disease

The progressive decline of renal function in chronic kidney disease (CKD) is characterized by both disruption of the microvascular architecture and the accumulation of fibrotic matrix. One angiogenic pathway recently identified as playing an essential role in renal vascular development is the stromal cell-derived factor-1α (SDF-1)/CXCR4 pathway. Because similar developmental processes may be recapitulated in the disease setting, we hypothesized that the SDF-1/CXCR4 system would regulate microvascular health in CKD. Expression of CXCR4 was observed to be increased in the kidneys of subtotally nephrectomized (SNx) rats and in biopsies from patients with secondary focal segmental glomerulosclerosis (FSGS), a rodent model and human correlate both characterized by aberration of the renal microvessels. A reno-protective role for local SDF-1/CXCR4 signaling was indicated by i) CXCR4-dependent glomerular eNOS activation following acute SDF-1 administration; and ii) acceleration of renal function decline, capillary loss and fibrosis in SNx rats treated with chronic CXCR4 blockade. In contrast to the upregulation of CXCR4, SDF-1 transcript levels were decreased in SNx rat kidneys as well as in renal fibroblasts exposed to the pro-fibrotic cytokine transforming growth factor β (TGF-β), the latter effect being attenuated by histone deacetylase inhibition. Increased renal SDF-1 expression was, however, observed following the treatment of SNx rats with the ACE inhibitor, perindopril. Collectively, these observations indicate that local SDF-1/CXCR4 signaling functions to preserve microvascular integrity and prevent renal fibrosis. Augmentation of this pathway, either purposefully or serendipitously with either novel or existing therapies, may attenuate renal decline in CKD.

Sex Differences in Myocardial TNF Signaling-Modulated SDF-1 Expression following Acute Ischemic Injury

Global myocardial ischemia/reperfusion (I/R) occurs during cardiac operations. This I/R injury increases production of tumor necrosis factor-α (TNF) instantly and upregulates expression of stromal cell-derived factor-1α (SDF-1). Based on published data from our laboratory and other groups, local produced TNF contributes to cardiac dysfunction via binding to its receptor (TNFR1)-initiated pathways, whereas SDF-1 mediates acute cardioprotection. In addition, we have previously shown that female hearts have improved cardiac function associated with TNFR1 signaling resistance and exhibit higher SDF-1 levels compared to male hearts following acute I/R.

Differential expressions of stromal cell-derived factor-1α and vascular endothelial growth factor in the placental bed of pregnancies complicated by preeclampsia

Objective: The aim of this study is to examine the differential expression of stromal cell-derived factor-1α (SDF-1α)/CXCR4 and vascular endothelial growth factor (VEGF) in the third trimester placental bed of normotensive controls and preeclamptic patients. Methods: Placental bed tissues were collected from 15 patients with preeclampsia (PE) and 15 gestational-matched normotensive controls at the time of their cesarean delivery. Placental bed expressions of SDF-1α, CXCR4 and VEGF were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR and immunohistochemical staining. Results: No statistical difference was found between the PE and the normotensive control group with respect to their age and parity, gravidity and body mass index. The placental bed expressions of SDF-1α/CXCR4 and VEGF were significantly decreased in the PE group compared with the normotensive control group. Conclusions: This study showed decreased expressions of SDF-1α/CXCR4 and VEGF in the third trimester placental bed of pregnancies with PE. This result suggests that decreased expressions of SDF-1α/CXCR4 and VEGF in the placental bed could be associated with the pathogenesis of PE.

Activator Protein-2α Mediates Carbon Monoxide–Induced Stromal Cell–Derived Factor-1α Expression and Vascularization in Ischemic Heart

Increased cardiac stromal cell-derived factor-1α (SDF-1α) expression promotes neovascularization and myocardial repair after ischemic injury through recruiting stem cells and reducing cardiomyocyte death. Previous studies have shown that heme oxygenase-1 and its reaction byproduct, carbon monoxide (CO), induce SDF-1α expression in ischemic heart. However, the mechanism underlying heme oxygenase-1/CO-induced cardiac SDF-1α expression remains elusive. This study aims to investigate the signaling pathway and the transcriptional factor that mediate CO-induced SDF-1α gene expression and cardioprotection. CO gas and a CO-releasing compound, tricarbonyldichlororuthenium (II) dimer, dose-dependently induced SDF-1α expression in primary neonatal cardiomyocytes and H9C2 cardiomyoblasts. Promoter luciferase-reporter assay, electrophoretic mobility shift assay, and chromatin immunoprecipitation demonstrated that the activator protein 2α (AP-2α) mediated tricarbonyldichlororuthenium (II) dimer-induced SDF-1α gene transcription. Tricarbonyldichlororuthenium (II) dimer induced AP-2α expression via protein kinase B (AKT)-dependent signaling. AKT inhibition or AP-2α knockdown reduced tricarbonyldichlororuthenium (II) dimer-induced SDF-1α expression. Coronary ligation induced transient increases of cardiac AP-2α and SDF-1α expression, which were declined at 1 week postinfarction in mice. Periodic exposure of coronary-ligated mice to CO (250 ppm for 1 hour/day, 6 days) resumed the induction of AP-2α and SDF-1α gene expression in infarcted hearts. Immunohistochemistry and echocardiography performed at 4 weeks after coronary ligation revealed that CO treatment enhanced neovascularization in the myocardium of peri-infarct region and improved cardiac function. CO-mediated SDF-1α expression and cardioprotection was ablated by intramyocardial injection of lentivirus bearing specific short hairpin RNA targeting AP-2α. Our data demonstrate that AKT-dependent upregulation of AP-2α is essential for CO-induced SDF-1α expression and myocardial repair after ischemic injury.

Hematopoietic recovery following chemotherapy is improved by BADGE-induced inhibition of adipogenesis

This study was designed to investigate the role of increased adipocytes in the bone marrow (BM) niche induced by high-dose chemotherapy in hematopoietic recovery. Arabinosylcytosine (Ara-C) was administered to adult C57BL/6J mice to induce adipogenesis in the BM. We investigated the effects of adipogenesis on hematopoietic recovery following chemotherapy, using the peroxisome proliferator-activated receptor gamma inhibitor, bisphenol A diglycidyl ether (BADGE). Adipocyte hyperplasia could be induced by Ara-C treatment in BM and inhibited by BADGE. The accelerated recovery of leukocyte counts, increased colony forming units, and a higher proportion of Ki67(+)CD45(+) BM cells and Ki67(+)Lin(-)Sca1(+)c-kit(+) hematopoietic stem cells were observed in the long bone marrow of adipocyte-inhibited mice, as well as an increase in the number of CD45(+) BM cells in the tail fatty marrow compared to controls. Adipocytes participated in creating a distinctive niche for hematopoietic cells. In addition, lower expression of stromal cell-derived factor-1α and hypoxia-inducible factor-1 alpha were detected in the BADGE-treated group. These results indicate that hematopoietic recovery is improved following chemotherapy in adipogenesis-inhibited mice. In addition, adipocytes may create an individual niche that affects the proliferation and migration of hematopoietic cells in vitro and in vivo.

Évolution de la fonction respiratoire après dix ans de plongée professionnelle

To investigate whether transmyocardial drilling revascularization combined with heparinized basic fibroblast growth factor (bFGF)-incorporating degradable stent implantation (TMDRSI) can promote myocardial regeneration after acute myocardial infarction (AMI).A model of AMI was generated by ligating the mid-third of left anterior descending artery (LAD) of miniswine. After 6 h, the animals were divided into none-treatment (control) group (n = 6) and TMDRSI group (n = 6). For TMDRSI group, two channels with 3.5 mm in diameter were established by a self-made drill in the AMI region, into which a stent was implanted. Expression of stromal cell-derived factor-1α (SDF-1α) and CXC chemokine receptor 4 (CXCR4), cardiac stem cell (CSC)-mediated myocardial regeneration, myocardial apoptosis, myocardial viability, and cardiac function were assessed at various time-points.Six weeks after the operation, CSCs were found to have differentiated into cardiomyocytes to repair the infarcted myocardium, and all above indices showed much improvement in the TMDRSI group compared with the control group (P < 0.001).The new method has shown to be capable of promoting CSCs proliferation and differentiation into cardiomyocytes through activating the SDF-1/CXCR4 axis, while inhibiting myocardial apoptosis, thereby enhancing myocardial regeneration following AMI and improving cardiac function. This may provide a new strategy for myocardial regeneration following AMI.

Connective Tissue Growth Factor (CTGF) Regulates Mesenchymal Stromal Cell De-Differentiation Into Adipocyte Progenitors and Facilitates Leukemic Cell Homing to Extra-Medullary Bone Marrow

Abstract 2391Connective tissue growth factor (CTGF) regulates extracellular matrix production, chemotaxis, cell proliferation and integrin expression. Recent reports suggest that recombinant CTGF transforms mesenchymal stromal cells (MSCs) into fibroblast like cells and inhibits their differentiation potential. We have recently shown that stable knockdown of CTGF expression in bone marrow derived MSCs rendered them quiescent and increased their adipocyte differentiation potential (Battula et al., ASH 2010 abstract 3845, Blood, Vol. 116). Based on these findings, we hypothesized that inhibition of CTGF expression modifies stem cell properties of MSCs and may affect leukemic cell homing. To test this hypothesis, bone marrow derived MSCs were transduced with lentivirus expressing either CTGFshRNA or control vector. Down-regulation of CTGF mRNA by ∼75% was observed in CTGF-KD-MSCs compared to empty vector control-MSCs. To examine the stem cell potential of CTGF-KD-MSCs, embryonic stem cell markers including oct-4, nanog, sox2 were analyzed. Real-time RT-PCR analysis revealed 2–3 fold up regulation of these genes in CTGF-KD-MSCs compared to controls indicating increased stemness. To test if leukemic cells home differentially to CTGF-KD-MSCs, we utilized our recently developed extra-medullary human bone marrow model by implanting a carrier impregnated with BM-MSC mixed with endothelial progenitor cells (EPCs) subcutaneously into NOG mice. These implants generate extra-medullary bone marrow (EXM-BM) in 6–8 weeks and resemble the normal bone marrow microenvironment. In-vivo imaging confirmed that both cell types formed EXM-BM with positive Osteosense binding which reflects the presence of hydroxyapatite. H&E staining of bone sections revealed that CTGF-KD-MSCs derived EXM-BM displayed more spongy bone compared to control-MSCs. To examine the extent of adipocytic differentiation in CTGF-KD-MSCs derived bone pellets, expression of adipocyte-specific markers PPAR-γ and C/EBPα was analyzed. Cells residing in the spongy EXM-BM region expressed high levels of nuclear PPAR-γ and C/EBPα, confirming differentiation into mature adipocytes. These markers were negative in the stromal/endothelial compartment of CTGF-KD-MSCs derived EXM-BM or control EXM-BM. When Nalm-6 (B-ALL cell line) cells expressing firefly luciferase and YFP were transplanted into these mice, leukemic cells migrated 10 fold more avidly towards CTGF-KD-MSCs derived EXM-BM compared to control EXM-BM in the same mouse (n=5). Immunohisto-chemical analysis demonstrated preferential homing of leukemic cells inside spongy regions of the EXM-BM derived from CTGF-KD-MSCs and control-MSCs. To investigate the mechanism behind the leukemic cell homing into CTGF-KD-MSCs derived EXM-BM, expression of stromal cell-derived factor-1α (SDF1α), a major factor involved in leukemic cell homing to bone marrow, was analyzed in both cell types by qRT-PCR. CTGF-KD-MSCs expressed 3-fold higher levels of SDF-1α compared to control cells indicating that SDF1α secretion by CTGF-KD-MSCs derived bone marrow might enhance the leukemia cell homing. In summary, these findings suggest that CTGF plays a crucial role in the regulation of stemness and differentiation of MSCs and affects the homing of leukemic cells to the bone marrow microenvironment. Targeting adipocyte progenitors may reduce the lodging of leukemic cells in the bone marrow niche and enhance chemosensitivity of leukemic cells within the BM microenvironment. Disclosures:No relevant conflicts of interest to declare.

Expression of stromal cell-derived factor-1α is an independent risk factor for lymph node metastasis in early gastric cancer

Lymph node metastasis is considered to be a significant prognostic factor for early gastric cancer (EGC). However, no real consensus exists on which patient and/or tumor characteristics are associated with lymph node metastasis. We investigated whether stromal cell-derived factor (SDF)-1α expression correlates with lymph node metastasis in patients with EGC by immunohistochemically examining the expression of SDF-1α in 138 archival tissue specimens of EGC. Of these specimens, 59 (42.8%) and 79 (57.2%) were grouped into SDF-1α-positive and SDF-1α-negative groups, respectively. No significant differences existed with respect to age, gender, tumor location, proportion of tumors >20 mm in size, macroscopic type, depth of invasion or histology between the SDF-1α-positive and -negative groups. However, the SDF-1α-positive group was significantly correlated with lymphovascular invasion and lymph node metastasis. Results of the univariate analyses indicated that lymphovascular invasion, undifferentiated histology and SDF-1α positivity were statistically significant risk factors affecting lymph node metastasis in patients with EGC. Multivariate analyses showed that lymphovascular invasion [hazard ratio (HR), 8.595; 95% confidence interval (CI), 1.694-43.595; P=0.009], undifferentiated histology (HR, 2.965; 95% CI, 1.037-8.471; P=0.043) and SDF-1α positivity (HR, 2.108; 95% CI, 1.316-10.135; P=0.013) were independent risk factors predicting lymph node metastasis in EGC. In conclusion, these results suggest that SDF-1α expression in tumor cells is a predictive marker of lymph node metastasis in EGC.

Exogenous basic fibroblast growth factor promotes cardiac stem cell-mediated myocardial regeneration after miniswine acute myocardial infarction

To investigate the effects of exogenous basic fibroblast growth factor (bFGF) on myocardial regeneration after acute myocardial infarction (AMI). AMI models were established by ligating the mid-third of left anterior descending artery, thereafter, miniswines were randomly divided into control (none treatment, n = 6) and bFGF groups (n = 6). For the bFGF group, bFGF (100 μg) was injected with a sterile microinjection at five sites within the ischemic region. 5-Bromo-2-deoxyuridine (250 mg) was administrated intravenously twice a week after the operation, to label cells undergoing DNA replication. The expression of stromal cell-derived factor-1α (SDF-1α) and CXC chemokine receptor 4 (CXCR4), cardiac stem cell-mediated myocardial regeneration, myocardial apoptosis, histological and immunohistochemical analyses, and cardiac function were evaluated at different time points. Four weeks after bFGF therapy, it showed an increased vessel density and myocardial perfusion (P < 0.001), upregulative expression of SDF-1α and CXCR4 (P < 0.001), increased c-kit and 5-bromo-2-deoxyuridine-positive cells (P < 0.001), enhanced myocardial viability (P < 0.001), and improved left ventricular ejection fraction (P = 0.007), compared with the control. Exogenous bFGF was shown to have increased angiogenesis and myocardial perfusion, promoted myocardial regeneration by activating the SDF-1α/CXCR4 axis, and thereby improved the cardiac function, which may provide a new therapeutic strategy for AMI.