Syringaresinol inhibits cardiorenal fibrosis through HSP90 in a cardiorenal syndrome type 2

Background Syringaresinol processes anti-inflammatory and antioxidative activity. However, the effects of syringaresinol on cardiorenal fibrosis caused by cardiorenal syndrome type 2 (CRS2) are unclear. Methods Molecular docking predicted binding activity of syringaresinol to heat shock protein 90 (HSP90). The toxicity of a 4-weeks treatment with 20 mg/kg of syringaresinol was observed by measuring serum pro-inflammatory cytokines levels and by cardiorenal pathology. A CRS2 rad model was established by myocardial infarction using ligation over an 8 week-period. Rats were divided into five groups, including sham, CRS2, pimitespib, syringaresinol, and HSP90 + syringaresinol. Rats were received a 4-weeks daily treatment with 10 mg/kg pimitespib (a HSP90 inhibitor) or 20 mg/kg syringaresinol. Recombinant adeno-associated virus (rAAV) carrying a periostin (PE) promoter driving the expression of wild-type HSP90 (rAAV9-PE-HSP90, 1 × 10 11 μg) was treated intravenously once in CRS2 model rats. Cardiorenal function and pathology were assessed. Expressions of HSP90 and TGF-β1 in the myocardium and kidney were measured by immunohistochemistry and western blotting. Results Syringaresinol showed good binding activity with HSP90, and no signs of toxicity in rats following treatment. Pimitespib or syringaresinol significantly improved the cardiorenal function and fibrosis in rats with CRS2. Meanwhile, the rAAV9-PE-HSP90 injection obviously blocked the effects of syringaresinol. Conclusions Syringaresinol targets HSP90 to suppress CRS2-induced cardiorenal fibrosis, providing a promising therapeutic drug for CRS2.