MiroRNA-21 mediates myocardial fibroblasts paracrine stimulated by indoxyl sulfate in vitro / 中华肾脏病杂志

Objective To explore the expression of miroRNA-21 (miRNA-21) in myocardial fibroblasts stimulated by indoxyl sulfate (IS) and its role on paracrine factors of myocardial fibroblasts.Methods Myocardial fibroblasts which derived from C57BL/6J mice were divided into control group and IS group,and their expressions of miRNA-21 were detected by real time PCR after 48 h.MiRNA-21 inhibitor transfection was applied to silence miRNA-21 expression.Myocardial fibroblasts were divided into creatinine (Scr) group (Scr treated for 48 h),Scr+IS group (Scr and 50 μmol/L IS treated for 48 h),Scr+miRNA-21 inhibitor group (miRNA-21 inhibitor treated for 24 h and then Scr treated for 48 h) and Scr+miRNA-21 inhibitor+ IS group (miRNA-21 inhibitor pretreated for 24 h and then Scr and IS treated for 48 h).Enzyme-linked immunosorbent assay was performed to evaluate the expressions of interleukin-1 (IL-1),interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α).Western blotting was applied to detect the expressions of transforming growth factor-β (TGF-β),matrix metalloproteinases 2 (MMP2),matrix metalloproteinases 9 (MMP9) and tissue inhibitor of metalloproteinases 1 (TIMP1).Results The expression of miRNA-21 was obviously increased in IS group than that in control group (P ＜ 0.01).Compared with those in Scr group,the expressions of IL-1,IL-6,TNF-α,TGF-β,MMP2 and MMP9 significantly increased (all P ＜ 0.05),while the expression of TIMP1 decreased (P ＜ 0.05).When the expression of miRNA-21 was inhibited,the expressions of IL-1,IL-6,TNF-α,TGF-β and MMP2 in Scr+miRNA-21 inhibitor+IS group significantly decreased than those in Scr+IS group (all P ＜0.05),and the expression of TIMP1 decreased further (P ＜ 0.05).Conclusions IS can promote the expression of miRNA-21 in myocardial fibroblasts.MiRNA-21 plays an important role in regulating inflammatory factors and pro-fibrogenic cytokines in myocardial fibroblasts.

Effect of Hypoxic Paracrine Media on Calcium-Regulatory Proteins in Infarcted Rat Myocardium

BACKGROUND AND OBJECTIVES: An increase in intracellular calcium concentration due to loss of Ca2+ homeostasis triggers arrhythmia or cardiac cell death in the heart. Paracrine factors released from stem cells have beneficial cardioprotective effects. However, the mechanism of modulation of Ca2+ homeostasis by paracrine factors in ischemic myocardium remains unclear. MATERIALS AND METHODS: We isolated rat bone marrow-derived mesenchymal stem cells (MSCs), and prepared paracrine media (PM) from MSCs under hypoxic or normoxic conditions (hypoxic PM and normoxic PM). We induced rat myocardial infarction by left anterior descending ligation for 1 hour, and treated PM into the border region of infarcted myocardium (n=6/group) to identify the alteration in calcium-regulated proteins. We isolated and stained the heart tissue with specific calcium-related antibodies after 11 days. RESULTS: The hypoxic PM treatment increased Ca2+-related proteins such as L-type Ca2+ channel, sarcoplasmic reticulum Ca2+ ATPase, Na+/K+ ATPase, and calmodulin, whereas the normoxic PM treatment increased those proteins only slightly. The sodium-calcium exchanger was significantly reduced by hypoxic PM treatment, compared to moderate suppression by the normoxic PM treatment. CONCLUSION: Our results suggest that hypoxic PM was significantly associated with the positive regulation of Ca2+ homeostasis in infarcted myocardium.

Epigallocatechin-3-gallate inhibits paracrine and autocrine hepatocyte growth factor/scatter factor-induced tumor cell migration and invasion

Aberrant activation of hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, Met, is involved in the development and progression of many human cancers. In the cell-based screening assay, (-)epigallocatechin-3-gallate (EGCG) inhibited HGF/SF-Met signaling as indicated by its inhibitory activity on HGF/SF-induced cell scattering and uPA activation (IC50 = 15.8 microg/ml). Further analysis revealed that EGCG at low doses specifically inhibited HGF/SF-induced tyrosine phosphorylation of Met but not epidermal growth factor (EGF)-induced phosphorylation of EGF receptor (EGFR). On the other hand, high-dose EGCG decreased both Met and EGFR proteins. We also found that EGCG did not act on the intracellular portion of Met receptor tyrosine kinase, i.e., it inhibited InlB-dependent activation of Met but not NGF-induced activation of Trk-Met hybrid receptor. This inhibition decreased HGF-induced migration and invasion by parental or HGF/SF-transfected B16F10 melanoma cells in vitro in either a paracrine or autocrine manner. Furthermore, EGCG inhibited the invasion/metastasis of HGF/SF-transfected B16F10 melanoma cells in mice. Our data suggest the possible use of EGCG in human cancers associated with dysregulated paracrine or autocrine HGF/SF-Met signaling.