poricoic-acid-a and Fibrosis

Renal interstitial fibrosis is the common pathological process of various chronic kidney diseases to end-stage renal disease. Inhibition of fibroblast activation attenuates renal interstitial fibrosis. Our previous studies show that poricoic acid A (PAA) isolated from Poria cocos is a potent anti-fibrotic agent. In the present study we investigated the effects of PAA on renal fibroblast activation and interstitial fibrosis and the underlying mechanisms. Renal interstitial fibrosis was induced in rats or mice by unilateral ureteral obstruction (UUO). UUO rats were administered PAA (10 mg·kg

Topics: Animals; beta Catenin; Fibroblasts; Fibrosis; Kidney; Kidney Diseases; Mice; Molecular Docking Simulation; Rats; Signal Transduction; Sirtuin 3; Transforming Growth Factor beta1; Triterpenes; Ureteral Obstruction

In chronic kidney disease, although fibrosis prevention is beneficial, few interventions are available that specifically target fibrogenesis. Poricoic acid A (PAA) isolated from Poria cocos exhibits anti-fibrotic effects in the kidney, however the underlying mechanisms remain obscure.. We isolated PAA and investigated its effects and the underlying mechanisms in renal fibrosis.. Unilateral ureteral obstruction (UUO) and 5/6 nephrectomy (Nx) animal models and TGF-β1-induced renal fibroblasts (NRK-49F) were used to investigate the anti-fibrotic activity of PAA and its underlying mechanisms.. Western blots, qRT-PCR, immunofluorescence staining, co-immunoprecipitation and molecular docking methods were used. Knock-down and knock-in of adenosine monophosphate-activated protein kinase (AMPK) in the UUO model and cultured NRK-49F cells were employed to verify the mechanisms of action of PAA.. PAA improved renal function and alleviated fibrosis by stimulating AMPK and inhibiting Smad3 specifically in Nx and UUO models. Reduced AMPK activity was associated with Smad3 induction, fibroblast activation, and the accumulation and aberrant remodelling of extracellular matrix (ECM) in human renal puncture samples and cultured NRK-49F cells. PAA stimulated AMPK activity and decreased fibrosis in a dose-dependent manner, thus showing that AMPK was essential for PAA to exert its anti-fibrotic effects. AMPK deficiency reduced the anti-fibrotic effects of PAA, while AMPK overexpression enhanced its effect.. PAA activated AMPK and further inhibited Smad3 specifically to suppress fibrosis by preventing aberrant ECM accumulation and remodelling and facilitating the deactivation of fibroblasts.

Topics: AMP-Activated Protein Kinases; Animals; Case-Control Studies; Cell Line; Dose-Response Relationship, Drug; Extracellular Matrix; Fibroblasts; Fibrosis; Humans; Kidney; Kidney Diseases; Male; Mice, Inbred BALB C; Molecular Docking Simulation; Rats, Sprague-Dawley; Smad3 Protein; Transforming Growth Factor beta1; Triterpenes; Ureteral Obstruction

Tubulo-interstitial fibrosis is the final pathway in the progression of chronic kidney disease (CKD) to kidney failure. The renin-angiotensin system (RAS) plays a major role in CKD progression. Hence, we determined the efficacy of novel RAS inhibitors isolated from Poria cocos against renal fibrosis.. Effects of three novel tetracyclic triterpenoid compounds, poricoic acid ZC (PZC), poricoic acid ZD (PZD) and poricoic acid ZE (PZE), were investigated on TGFβ1- and angiotensin II (AngII)-treated HK-2 cells and unilateral ureteral obstruction (UUO) in mice. Immunofluorescence staining, quantitative real-time PCR, siRNA, co-immunoprecipitation and Western blot analyses were used to evaluate expression of key molecules in RAS, Wnt/β-catenin and TGFβ/Smad pathways.. Addition of the above compounds to culture media and their administration to UUO mice: (i) significantly attenuated epithelial-to-mesenchymal transition and extracellular matrix production in TGFβ1- and AngII-treated HK-2 cells and UUO mice by inhibiting Wnt/β-catenin pathway activation and Smad3 phosphorylation; (ii) selectively inhibited Smad3 phosphorylation by blocking the interaction of TGFBR1 with Smad3; and (iii) specifically inhibited Smad3 activation. PZC and PZD showed a strong inhibitory effect on all RAS components, and PZE showed a strong inhibitory effect on renin. Furthermore, the secolanostane tetracyclic triterpenoids, PZC and PZD, showed a stronger inhibitory effect than the lanostane tetracyclic triterpenoid PZE. Therefore, compounds with secolanostance skeleton showed stronger bioactivity than those with lanostance skeleton.. The secolanostane tetracyclic triterpenoids effectively blocked RAS by simultaneously targeting multiple RAS components and lanostane tetracyclic triterpenoids inhibited renin and protected against tubulo-interstitial fibrosis.

Topics: Animals; beta Catenin; Cell Survival; Cells, Cultured; Fibrosis; Humans; Kidney; Male; Mice; Mice, Inbred BALB C; Molecular Conformation; Phosphorylation; Renin-Angiotensin System; Smad3 Protein; Triterpenes; Wnt Signaling Pathway