1, 25(OH)2D3 regulates the proliferation, fibrosis, and autophagy of mesangial cells induced by high glucose via the VDR/mTOR pathway].

Objective To investigate the effects of 1, 25(OH)2D3 on the proliferation, fibrosis, and autophagy of mesangial cells mediated by high glucose and its mechanisms. Methods Rat glomerular mesangial cell line HBZY-1 was cultured in vitro and transfected with small interfering RNA (siRNA) to silence vitamin D receptor (VDR), and the transfection efficiency was detected by reverse transcription-PCR and Western blot. The cultured mesangial cells were divided into five groups: normal glucose group (NG group), high glucose group (HG group), high glucose combined with 1, 25(OH)2D3 group (HG-VD group), high glucose combined with 1, 25(OH)2D3 and si-VDR group (HG-VD-si-VDR group), high glucose combined with 1, 25(OH)2D3 and mTOR activator MHY1485 group (HG-VD-MHY1485 group); the proliferation of mesangial cells was detected by MTT assay and EdU staining, and the levels of fibronectin (FN), collagen type I (Col1), and collagen type IV (Col4) were detected by ELISA. The number of autophagosomes in mesangial cells of each group was observed by transmission electron microscopy. The protein expression of autophagy marker LC3 in mesangial cells was detected by immunofluorescence cytochemistry. The expressions of transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA), and p62, the phosphorylated mTOR (p-mTOR), and the LC3 II/LC3 I ratio were detected by Western blot. Results The expressions of VDR mRNA and protein in HBZY-1 cells were significantly down regulated after si-VDR transfection. Compared with those in the NG group, the proliferation ability, the expression levels of cytokines FN, Col1, and Col4, and the p-mTOR, TGF-β1, α-SMA, and P62 protein expression levels were significantly increased, while the number of autophagosomes, the positive expression rate of autophagy marker LC3 II, and the LC3 II/LC3 I ratio were significantly decreased in mesangial cells of HG group, HG-VD group, HG-VD-si-VDR group, and HG-VD-MHY1485 group. The above changes were significantly reduced in HG-VD group than in HG group, HG-VD-si-VDR group, and HG-VD-MHY1485 group, and there was no significant difference in the latter three groups. Conclusion Inhibition of VDR expression or increase of mTOR activation can effectively counteract the inhibitory effect of 1, 25(OH)2D3 on the high glucose induced proliferation, fibrosis increase, and autophagy decrease of mesangial cells.

Citation

Gang Liu, Guochen Ren, Xiaoping Yang. 1, 25(OH)2D3 regulates the proliferation, fibrosis, and autophagy of mesangial cells induced by high glucose via the VDR/mTOR pathway]. Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology. 2022 Mar;38(3):224-230

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PMID: 35365987

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