nsc-74859 and Ureteral-Obstruction

Transforming growth factor β 1 (TGFβ1) plays a critical role in the epithelial-to-mesenchymal transition (EMT) of renal tubular epithelial cells (TECs) during renal injury, a major cause of acute renal failure, renal fibrosis and obstructive nephropathy. However, the underlying molecular mechanisms remain ill-defined. Here, we addressed this question.. Expression of TGFβ1, Snail, and phosphorylated Stat3 was examined by immunohistochemistry in the kidney after induction of unilateral ureteral obstruction (UUO) in mice. In vitro, primary TECs were purified by flow cytometry, and then challenged with TGFβ1 with/without presence of specific inhibitors for phosphorylation of SMAD3 or Stat3. Protein levels were determined by Western blotting.. We detected significant increases in Snail and phosphorylated Stat3, an activated form for Stat3, in the kidney after induction of UUO in mice. In vitro, TGFβ1-challenged primary TECs upregulated Snail, in a SMAD3/Stat3 dependent manner.. Our study sheds light on the mechanism underlying the EMT of TECs after renal injury, and suggests Stat3 signaling as a promising innovative therapeutic target for prevention of renal fibrosis.

Topics: Aminosalicylic Acids; Animals; Benzenesulfonates; Cadherins; Cells, Cultured; Epithelial Cells; Epithelial-Mesenchymal Transition; Fibrosis; Kidney Tubules; Male; Mice; Mice, Inbred C57BL; Phosphorylation; Real-Time Polymerase Chain Reaction; Signal Transduction; Smad3 Protein; Snail Family Transcription Factors; STAT3 Transcription Factor; Transforming Growth Factor beta1; Tubulin; Ureteral Obstruction

Topics: Aminosalicylic Acids; Animals; Benzenesulfonates; Fibronectins; Fibrosis; Kidney; Kidney Diseases; Male; Matrix Metalloproteinase 9; Mesenchymal Stem Cells; Rats, Sprague-Dawley; STAT3 Transcription Factor; Ureteral Obstruction

Accumulation of both interstitial myofibroblasts and excessive production of extracellular matrix proteins is a common pathway contributing to chronic kidney disease. In a number of tissues, activation of STAT3 (signal transducer and activator of transcription 3) increases expression of multiple profibrotic genes. Here, we examined the effect of a STAT3 inhibitor, S3I-201, on activation of renal interstitial fibroblasts and progression of renal fibrosis. Treatment of cultured rat renal interstitial fibroblasts with S3I-201 inhibited their activation, as evidenced by dose- and time-dependent blockade of alpha-smooth muscle actin and fibronectin expression. In a mouse model of renal interstitial fibrosis induced by unilateral ureteral obstruction, STAT3 was activated, and administration of S3I-201 attenuated both this activation and extracellular matrix protein deposition following injury. S3I-201 reduced infiltration of the injured kidney by inflammatory cells and suppressed the injury-induced expression of fibronectin, alpha-smooth muscle actin, and collagen type-1 proteins, as well as the expression of multiple cytokines. Furthermore, S3I-201 inhibited proliferation and induced apoptosis preferentially in renal interstitial fibroblasts of the obstructed kidney. Thus, our results suggest that increased STAT3 activity mediates activation of renal interstitial fibroblasts and the progression of renal fibrosis. Inhibition of STAT3 signaling with S3I-201 may hold therapeutic potential for fibrotic kidney diseases.

Topics: Aminosalicylic Acids; Animals; Benzenesulfonates; Cell Line; Cells, Cultured; Disease Models, Animal; Extracellular Matrix Proteins; Fibroblasts; Fibrosis; Kidney Diseases; Kidney Failure, Chronic; Male; Mice; Mice, Inbred C57BL; Nephritis, Interstitial; Rats; Renal Insufficiency, Chronic; STAT3 Transcription Factor; Ureteral Obstruction