ObjectiveTo investigate the role of MG-132, a specific dipeptide proteasome inhibitor, on the proliferation, apoptosis and the related proteins in renal interstitial fibroblasts. MethodsRenal interstitial fibroblasts (NRK-49F) were induced by transforming growth factor β1 (TGF-β1, 5 μg/L) and pro-treated with MG-132 (0～5 μmol/L). The cell proliferation was measured with MTT method. Cell cycle and apoptosis were analyzed by flow cytometry. The apoptosis was also analyzed by Annexin V/PI staining and DNA ladder. Expression of p53, p27, p21, caspase-3, Bcl-2 and Bax protein was examined by Western blot. ResultsTGF-β1 (5 μg/L) could stimulate the proliferation of NRK-49F. MG-132 (0.25～5 μmol/L) could inhibit TGF-β1-induced proliferation in a dose-dependent manner through G1-arrest. TGF-β1 alone could not induce apoptosis (3.880%±0.365% vs 4.723%±1.582%). But pretreatment of MG-132 (0.1～2.5 μmol/L) could significantly induce apoptosis of TGF-β1-stimulated NRK-49F in a dose-dependent manner. Typical DNA ladder was also confirmed in these two groups in the DNA fragments analysis after being incubated with 2.5 μmol/L MG-132 with or without 5 μg/L TGF-β1. Western blot showed that MG-132 could activate the cell-cycle and apoptosis-related proteins such as p53, p21, caspase-3, Bax and inhibit Bcl-2 in a dose-dependent manner, while expression of p27 remained unchanged. ConclusionsProteasome inhibitor MG-132 can inhibit proliferation and induce the cell apoptosis in renal interstitial fibroblasts stimulated by TGF-β1. The mechanism may be associated to the mediation of p53, p21, caspase-3, Bcl-2 and bax pathways. Protoasome inhibitor may be a new strategy to treat renal interstitial fibrosis.

Objective To investigate the changes of expression of peroxisome proliferator-activated receptor γ (PPARγ) and its coregulators and monocyte chemotactic factor (MCP-1) treated with intedeukin-1β (IL-1β), and to analyze the mechanism of interaction of these factors. Methods Renal tubular cells (HK-2 cells) were cultured in vitro. Total cellular RNA was isolated for real-lime quantitative polymerase chain reaction (real-time PCR), nuclear extracts were prepared for Western blot analysis and EMSA. The supernatant was collected for ELISA after the treatment of IL-1β at different concentrations and time points. Results Under stimulus of different concentrations of IL-1β (0～20 μg/L) for 24 hours, the mRNA expression of PPARγ, SRC-1, SRC-2 and PGC-1 decreased significantly (P<0.05), meanwhile NCoR increased obviously (P<0.05). In further time-dependent experiment, the mRNA levels of SRC-2 and PGC-1 decreased by 57% and 48%, respectively, at 1 hour after treatment with 10 μg/L IL-1β (P<0.05). The expression of SRC-1 decreased by 43%only after 2 hours (P<0.05). The expression of NCoR was not obviously changed until stimulated by IL-1β for 8 hours (2.17 folds, P<0.05), then it decreased slowly. In the same time-dependent experiment, Western blot analysis showed that IL-1β (10 μg/L) significantly decreased the protein level of PPARγ at 4 hours (P<0.05). ELISA analysis revealed that the secretion of MCP-1 kept on rising and reached the peak (160.56±2.80) ng/L at 8 hours (P<0.01), then decreased to (50.82±1.25) ng/L at 24 hours (P<0.01). IL-1β could down-regulate the DNA binding activity of PPARγ, and the activity of NF-κB was up-regulated. Conclusions PPARγ and its eoregulators are closely related to MCP-1 and NF-κB during inflammation response in kidney. The activation of NF-κB by IL-1β leads to the decrease of PPARγ, and its coactivators expression levels, however the expression of MCP-1 and NCoR in renal tubular epithelial cells is up-regulated. PPARγ together with its coregulators participate in the inflammation response in kidney.

Non-muscle myosin heavy chain 9-related disease (MYH9-RD) is an autosomal dominant disease caused by the mutations of the MYH9 gene encoding the non-muscle mysoin heavy chain ⅡA and leads to abnormal accumulation of myosin in cells. These further causes functional disorders of the blood, eye, ear, kidney, and liver systems. MYH9-RD displays heterogeneous kidney involvement and outcomes, but doctors still lack understandings of the mechanism and treatment strategies, owing to difficulty of conducting renal biopsies. Here, we report a case of MYH9-RD with tail fragments heterozygous mutation, which renal pathology is presented as glomerular minor lesion. Moreover, we reviewed related relevant to strengthen clinical diagnosis and understanding of MYH9-RD.