Anti-TRPC6 (aa 868-931) polyclonal antibody

An increase in cytosolic free Ca2+ concentration ([Ca2+](cyt)) in pulmonary artery smooth muscle cells (PASMCs) triggers pulmonary vasoconstriction and stimulates PASMC proliferation leading to vascular wall thickening. Here, we report that STIM2 (stromal interaction molecule 2), a Ca2+ sensor in the sarcoplasmic reticulum membrane, is required for raising the resting [Ca2+](cyt) in PASMCs from patients with pulmonary arterial hypertension (PAH) and activating signaling cascades that stimulate PASMC proliferation and inhibit PASMC apoptosis. Downregulation of STIM2 in PAH-PASMCs reduces the resting [Ca2+](cyt), whereas overexpression of STIM2 in normal PASMCs increases the resting [Ca2+](cyt). The increased resting [Ca2+](cyt) in PAH-PASMCs is associated with enhanced phosphorylation (p) of CREB (cAMP response element-binding protein), STAT3 (signal transducer and activator of transcription 3), and AKT, increased NFAT (nuclear factor of activated T-cell) nuclear translocation, and elevated level of Ki67 (a marker of cell proliferation). Furthermore, the STIM2-associated increase in the resting [Ca2+](cyt) also upregulates the antiapoptotic protein Bcl-2 in PAH-PASMCs. Downregulation of STIM2 in PAH-PASMCs with siRNA (1) decreases the level of pCREB, pSTAT3, and pAKT and inhibits NFAT nuclear translocation, thereby attenuating proliferation, and (2) decreases Bcl-2, which leads to an increase of apoptosis. In summary, these data indicate that upregulated STIM2 in PAH-PASMCs, by raising the resting [Ca2+](cyt), contributes to enhancing PASMC proliferation by activating the CREB, STAT3, AKT, and NFAT signaling pathways and stimulating PASMC proliferation. The STIM2-associated increase in the resting [Ca2+](cyt) is also involved in upregulating Bcl-2 that makes PAH-PASMCs resistant to apoptosis, and thus plays an important role in sustained pulmonary vasoconstriction and excessive pulmonary vascular remodeling in patients with PAH.

Introduction. Focal segmental glomerulosclerosis (FSGS) ranks among nephrotic syndromes. Research shows that FSGS is brought about by several genes including transient receptor potential cation channel subfamily c member 6 (TRPC6). This study aimed to investigate TRPC6 gene in Iranian FSGS children. Materials and Methods. Twenty-six FSGS patients were included. They were all under 16 years old. Polymerase chain reaction amplification and sequencing were performed to examine exons 2 and 13 of TRPC6 gene. Results. Sampling was performed when the patients had a mean age of 9.26 +/- 3.19 years. Sixteen children were boys (61.5%); male-female ratio was 1.35:1. Four patients (15.4%) were diagnosed with TRPC6 variants. Three missense nonsynonymous mutations (C121S, D130V, and G162R) and 1 synonymous mutation (I111I) were detected. All variants were novel; in silico analysis predicted D130V and G162R as pathogenic. Patients with and without mutations were not different significantly regarding age at disease onset, sex, consanguinity, hypertension, hematuria, serum creatinine and albumin, rate of progression to kidney failure, response to steroids, and resistance to cyclosporine A and cyclophosphamide. Conclusions. This study examined exons 2 and 13 of TRPC6 gene in Iranian FSGS children. Four novel TRPC6 variants were detected; in silico analysis showed that 2 variants (D130V and G162R) could be pathogenic. It could be concluded that TRPC6 may be useful for genetic screening in Iranian FSGS children.