Indoxyl Sulfate Upregulates Prorenin Expression via Nuclear Factor-κB p65, Signal Transducer and Activator of Transcription 3, and Reactive Oxygen Species in Proximal Tubular Cells

We have recently found that indoxyl sulfate induces prorenin expression in proximal tubular cells. The present study aimed to determine whether nuclear factor-κB (NF-κB) p65, signal transducer and activator of transcription 3 (Stat3), and reactive oxygen species are involved in indoxyl sulfate-induced prorenin expression in cultured human proximal tubular cells (HK-2 cells). Effects of indoxyl sulfate on prorenin expression were determined using HK-2 cells with small interfering RNAs (siRNAs) specific to NF-κB p65 and Stat3, N-acetylcysteine, an antioxidant, and diphenyleneiodonium, an inhibitor of nicotinamide adenine dinucleotide phosphate oxidase. Indoxyl sulfate increased prorenin expression in HK-2 cells. siRNAs specific to NF-κB p65 and Stat3 inhibited indoxyl sulfate-induced prorenin expression. Both N-acetylcysteine and diphenyleneiodonium suppressed indoxyl sulfate-induced prorenin expression. Indoxyl sulfate upregulates the expression of prorenin via NF-κB p65, Stat3, and reactive oxygen species in proximal tubular cells.