RESUMO
NEW FINDINGS: What is the central question of this study? What is the role of the long non-coding RNA X-inactive specific transcript (XIST), which is up-regulated in injured podocytes and membranous nephropathy, in the pathogenesis of membranous nephropathy? What is the main finding and its importance? XIST was up-regulated in kidney tissue with membranous nephropathy and in injured podocytes. Down-regulation of XIST inhibited podocyte apoptosis. XIST negatively regulated miR-217, and miR-217 modulated Toll-like receptor 4. Inhibition of XIST suppressed podocyte apoptosis induced by angiotensin II via miR-217. ABSTRACT: Membranous nephropathy is often characterized by glomerular podocyte injury. Up-regulation of the long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) has been verified in membranous nephropathy and in injured podocytes. Here the role of XIST in podocyte injury and membranous nephropathy was explored. Quantitative real-time PCR and western blot were performed to detect the expression of XIST and miR-217, and Toll-like receptor 4 (TLR4) protein, respectively. Podocyte apoptosis was evaluated with flow cytometry. Interaction between XIST and miR-217 was analysed by RNA immunoprecipitation and RNA pull-down assay. A dual luciferase reporter assay was used to examine the interplay between miR-217 and TLR4. Up-regulation of the lncRNA XIST and angiotensin II (Ang II) and kidney and podocyte injury were indicated in kidney tissue of patients with membranous nephropathy. Increase of XIST and apoptosis were induced by Ang II in podocytes. Down-regulation of XIST reversed podocyte apoptosis induced by Ang II. MiR-217 was negatively regulated by XIST. MiR-217 controlled TLR4 by targeting its 3'-untranslated region. XIST modulated TLR4 through miR-217 and inhibition of XIST reduced podocyte apoptosis induced by Ang II via regulating miR-217. Down-regulation of XIST ameliorates podocyte apoptosis via the miR-217-TLR4 pathway, which may improve membranous nephropathy.
Assuntos
Apoptose/genética , Regulação para Baixo/genética , Glomerulonefrite Membranosa/genética , MicroRNAs/genética , Podócitos/patologia , RNA Longo não Codificante/genética , Transdução de Sinais/genética , Receptor 4 Toll-Like/genética , Adulto , Idoso , Angiotensina II/genética , Feminino , Humanos , Rim/patologia , Masculino , Pessoa de Meia-Idade , Regulação para Cima/genéticaRESUMO
Hyperglycemia and inflammation play important roles in the pathogenesis of diabetic nephropathy (DN). Brazilin might be an effective pharmacological agent against hyperglycemia and inflammation. In our present study, we explored whether brazilin mitigated pathological progression, inflammation, and extracellular matrix (ECM) accumulation in a mouse model of diabetic nephropathy. Brazilin reduced aggravated biochemical indices of DN (proteinuria and the serum glucose level) and renal hypertrophy. Brazilin also improved renal morphology and inhibited macrophage infiltration, as manifested by different pathological staining methods. Brazilin reduced the levels of pro-inflammatory cytokines and CD68, a macrophage marker, in the kidney cortex, as revealed by both RT-PCR and western blotting experiments. Furthermore, brazilin significantly downregulated the serum levels of pro-inflammatory cytokines and chemokines. Interestingly, brazilin significantly upregulated the levels of the anti-inflammatory factor IL-10, and prevented ECM accumulation. Brazilin reduced nuclear translocation of the NF-κB p65 subunit both in vitro and in vivo. Thus, brazilin might be a useful treatment for DN, through mitigating hypoglycemia, inflammation, and ECM accumulation.
