Interfering RNA against PKCα inhibits TNFα-induced IP3R1 expression and improves glomerular filtration rate in rats with fulminant hepatic failure

Abstract

We have reported that tumor necrosis factor-α (TNF-α) is critical for reduction of glomerular filtration rate (GFR) in rats with fulminant hepatic failure (FHF). The present study aims to evaluate the underlying mechanisms of decreased GFR during acute hepatic failure. Rats with FHF induced by D-galactosamine plus lipopolysaccharide (GalN/LPS) were injected intravenously with recombinant lentivirus harboring short hairpin RNA against the protein kinase Cα (PKCα) gene (LentishRNA- PKCα). GFR, serum levels of aminotransferases, creatinine, urea nitrogen, potassium, sodium, chloride, TNFα and endothelin-1 (ET-1), as well as type 1 inositol 1,4,5-trisphosphate receptor (IP3R1) expression in renal tissue were assessed. The effects of PKCα silencing on TNFα-induced IP3R1, specificity protein 1 (SP-1), and Ca2+Jun NH2-terminal kinase (JNK) expression, as well as cytosolic calcium content were determined in glomerular; mesangial cell (GMCs) with RNAi against PKCα. Renal IP3R1 overexpression was abrogated by pre-treatment with Lenti-shRNAPKCA2+. The PKCα silence significantly improved the compromised GFR, reduced Cr levels, and reversed the decrease in glomerular inulin space and the increase in glomerular calcium content in GalN/LPS-exposed rats. TNFα treatment increased expression of PKCα, IP3R1, specificity protein 1 (SP-1), JNK, and p-JNK in GMCs and increased Ca2+ release and binding activity of SP-1 to the IP3R1 promoter. These effects were blocked by transfection of siRNA against the PKCα gene, and the PKCα gene silence also restored cytosolic Ca2+ concentration. RNAi targeting PKCα inhibited TNFα-induced IP3R1 overexpression and in turn improved compromised GFR in the development of acute kidney injury during FHF in rats.