Expression and role of the TRPC family in TGF-β1-induced calcium influx in podocytes / 生理学报

The TRPC family consists of multiple important cationic channels in mammals that participate in a variety of physiological and pathological processes. Our previous studies have shown that transforming growth factor-β1 (TGF-β1) increases the expression of TRPC6 in podocytes, but the roles of other members of the TRPC family in podocytes require further investigation. In this study, we investigated the effect of TGF-β1 on the expression of the TRPC family and the role of the TRPC family in the changes of the intracellular Ca2+ concentration ([Ca2+]i) in podocytes induced by TGF-β1. The model of podocyte injury was established by treatment with TGF-β1 in immortalized glomerular podocytes (MPC5) in vitro. qRT-PCR and Western blot were used to detect the effect of TGF-β1 on the mRNA and protein expression of each TRPC family member. After the expression of each TRPC family member was knocked down by a siRNA-based approach and blocked by SKF96365, respectively, free cytosolic Ca2+ was measured using the fluorescent Ca2+ indicator Fluo-3/AM, and the dynamic change of [Ca2+]i in podocytes was detected by a dynamic high-speed calcium imaging system. The results showed that TGF-β1 increased the protein expression of TRPC1/3/6 in podocytes, but had no effects on the protein expression of TRPC4. The protein expression levels of TRPC5/7 were only affected by 4 ng/mL and 8 ng/mL TGF-β1, respectively. TGF-β1 increased TRPC1/3/6 mRNA levels in podocytes, however had no effects on TRPC4/5/7 mRNA. TGF-β1 significantly increased [Ca2+]i in podocytes. Knockdown of TRPC1/4/5/7 in podocytes had no significant effect on the [Ca2+]i induced by TGF-β1, but TRPC3/6 knockdown significantly decreased the [Ca2+]i. There was no significant difference in the [Ca2+]i between the TRPC6 siRNA-treated group and SKF96365-treated group, but the [Ca2+]i of the TRPC3 siRNA-treated group was significantly higher than that of SKF96365-treated group. These results demonstrate that TGF-β1 increases the expression of the TRPC1/3/6 in podocytes. TGF-β1 increases [Ca2+]i in podocytes, which is dependent on the TRPC3/6 expression. Our results also suggest that the effect of TRPC6 on [Ca2+]i in podocytes may be greater than that of TRPC3.

T cell receptor constant alpha chain gene +1592C/T polymorphism may not be associated with IgA nephropathy / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relationship between T cell receptor constant alpha chain (TCRCα) gene +1592C/T polymorphism and IgA nephropathy.</p><p><b>METHODS</b>TCRCα +1592C/T genotypes were identified by PCR-RFLP and direct sequencing in 244 Chinese Han patients with IgA nephropathy, who were classified according to their genotype into CC (188 cases), CT (54 cases) and TT (2 cases) groups. The clinical and pathological data of the patients were analyzed in relation to the TCRCα +1592C/T genotypes.</p><p><b>RESULTS</b>No significant differences in the clinical and biochemical indices were found in these patients with different TCRCα gene +1592C/T genotypes. TCRCα +1592C/T polymorphism was not found to contribute to severity or manifestations of renal pathology.</p><p><b>CONCLUSIONS</b>TCRCα+1592C/T polymorphism may not be associated with the susceptibility to IgA nephropathy in the Chinese Han population.</p>