ABSTRACT: To investigate whether nerve growth factor (NGF) induced angiogenesis of bone marrow mesenchymal stem cells (MSCs) and the underlying mechanisms.
Bone marrow MSCs were isolated from femors or tibias of Sprague-Dawley rat, and cultured. The cells were purified after 3 to 5 passages, seeded on Matrigel-coated 24-well plates and treated with NGF. Tube formation was observed 24 h later. Tropomyosin-related kinase A (TrkA) and p75NTR gene expression was examined using PCR analysis and flow cytometry. Growth curves were determined via cell counting. Expression of VEGF and pAkt/Akt were analyzed with Western blot.
NGF (25, 50, 100 and 200 μg/L) promoted tube formation of MSCs. The tubular length reached the maximum of a 2.24-fold increase, when the cells were treated with NGF (50 μg/L). NGF (50 μg/L) significantly enhanced Akt phosphorylation. Pretreatment with the specific PI3K inhibitor LY294002 (10 μmol/L) blocked NGF-stimulated Akt phosphorylation, tube formation and angiogenesis. NGF (25-200 μg/L) did not affect the expression of TrkA and vascular endothelial growth factor (VEGF), but significantly suppressed the expression of p75NTR. NGF (50 μg/L) markedly increased the proliferation of MSCs.
NGF promoted proliferation of MSCs and activated the PI3K/Akt signaling pathway, which may be responsible for NGF induction of MSC angiogenesis.
Acta Pharmacologica Sinica 12/2011; 32(12):1483-90. · 1.95 Impact Factor
ABSTRACT: Human embryonic stem cells (hESCs) have recently been reported as an unlimited source of mesenchymal stem cells (MSCs). The present study not only provides an identical and clinically compliant MSC source derived from hESCs (hESC-MSCs), but also describes the immunomodulative effects of hESC-MSCs in vitro and in vivo for a carbon tetrachloride (CCl(4))-induced liver inflammation model.
Undifferentiated hESCs were treated with Rho-associated kinase (ROCK) inhibitor and induced to fibroblast-looking cells. These cells were tested for their surface markers and multilineage differentiation capability. Further more, we analyzed their immune characteristics by mixed lymphocyte reactions (MLRs) and animal experiments.
hESC-MSCs show a homogenous fibroblastic morphology that resembles bone marrow-derived MSCs (BM-MSCs). The cell markers and differentiation potential of hESC-MSCs are also similar to those of BM-MSCs. Unlike their original cells, hESC-MSCs possess poor immunogenicity and can survive and be engrafted into a xenogenic immunocompetent environment.
The hESC-MSCs demonstrate strong inhibitory effects on lymphocyte proliferation in vitro and anti-inflammatory infiltration properties in vivo. This study offers information essential to the applications of hESC-MSC-based therapies and evidence for the therapeutic mechanisms of action.
Journal of Zhejiang University SCIENCE B 01/2011; 12(1):18-27. · 1.10 Impact Factor
ABSTRACT: To characterize the expression and function of midkine (MK) in an in vitro embryonic stem cell (ESC) culture system.
To investigate the potential roles of MK, the expression of MK in ESCs was evaluated by RT-PCR and immunocytochemistry. The effects of MK on the self-renewal of ESCs were measured using alkaline phosphatase assays, immunocytochemistry, RT-PCR and colony-forming assays. The mechanism of the growth-promoting effect of MK in mESCs was assessed by cell cycle analysis and Western blot analysis.
MK is expressed in mouse embryonic stem cells (mESCs), human embryonic stem cells (hESCs) and mouse embryonic fibroblasts (MEFs). MK promotes proliferation and self-renewal of mESCs both in feeder and feeder free culture systems. It also promotes self-renewal and proliferation of hESCs. Further study showed that MK promotes the growth of mESCs by inhibiting apoptosis while accelerating the progression toward the S phase, and enhances mESC self-renewal through PI3K/Akt signaling pathway.
MK plays profound roles in ESCs. MK/PTPzeta signaling pathway is a novel pathway in the signal network maintaining pluripotency of ESCs. The results extend our knowledge on pluripotency control of ESCs and the relationship between ESCs and cancers.
Acta Pharmacologica Sinica 05/2010; 31(5):629-37. · 1.95 Impact Factor
ABSTRACT: To study whether Tongxinluo (TXL) can induce angiogenesis in bone marrow mesenchymal stem cells (MSCs), and to investigate the underlying mechanism.
Bone marrow MSCs were obtained from male Sprague-Dawley rats. We established an angiogenesis model in vitro via matrigel experiment. MSCs were seeded on matrigel coated 24-well plates, and treated by TXL 50 and 100 mg/L. After 24 h, we observed the tube formations of MSCs in the matrigel. Cell migration ability was examined by wound scratch test and transwell assay. Expressions of vascular endothelial growth factor (VEGF), fetal liver kinase-1 (Flk-1), matrix metalloproteinase-2 (MMP-2), MMP-9, and tissue inhibitor of metalloproteinase-2 (TIMP-2) were analyzed at the protein level by Western blot. Gelatin zymography assay was applied to investigating the MSC paracrine abilities of pro-MMP-2 and activated MMP-2.
TXL promoted MSC tube formation in matrigel. The ratio of TXL 100 mg/L treated-MSC tubular length was increased 3.04-fold compared to the control group (P<0.05). Scratch test and transwell assay showed that TXL could improve the cell migration ability of MSCs. Western blot experiments showed that TXL promoted MSC synthesis of MMP-2, but it had no influence on the expressions of MMP-9 and TIMP-2. This effect was confirmed by gelatin zymography assay, which showed that TXL increased MSC secretion of pro-MMP-2 and activated MMP-2. VEGF expression of TXL treated-MSCs was increased compared to the control group. The expression of Flk-1 was not different among the groups.
This study demonstrates that TXL can promote the tube formation of MSCs, and the underlying mechanisms are associated with increased migration ability of MSCs and the up-regulation of MMP-2 and VEGF expressions.
Journal of Zhejiang University SCIENCE B 12(8):644-51. · 1.10 Impact Factor