Periostin contributes to renal and cardiac dysfunction in rats with chronic kidney disease: Reduction of PPARα.

POSTN knockdown inhibits the formation of NLRP3 inflammasome in rat myocardium.Periostin (POSTN), an extracellular matrix protein, and peroxisome proliferator-activated receptor alpha (PPARα), a ligand-activated nuclear transcription factor, are reported to be involved in renal and cardiac dysfunction associated with chronic kidney disease (CKD), respectively. This study is performed to investigate how POSTN-PPARα axis affects the progress of CKD. In vivo, adenovirus particles containing POSTN short hairpin RNA (Ad-shPOSTN) were intravenously given to Sprague Dawley rats following 5/6 nephrectomy. The effects of Ad-shPOSTN on CKD and CKD-associated cardiovascular disease were evaluated. In vitro, NRK-52E renal tubular epithelial cells were infected with Ad-shPOSTN or Ad-POSTN (overexpression) to explore whether POSTN affected collagen deposition by regulating PPARα. We found that POSTN expression was upregulated, while PPARα was downregulated in the injured renal and left ventricular tissues of nephrectomized rats. Ad-shPOSTN improved renal function, prevented cardiac dysfunction, and attenuated organ fibrosis in nephrectomized rats. The expression levels of renal and myocardial PPARα were increased following Ad-shPOSTN administration. Furthermore, POSTN silencing suppressed the formation of NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome in the myocardium: the levels of NLRP3, anti-apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), cleaved caspase 1, mature interleukin (IL)-1β and IL-18 were reduced. In NRK-52E cells, forced overexpression of POSTN directly inhibited PPARα expression and induced collagen deposition. WY14643, a PPARα agonist, suppressed POSTN-induced collagen deposition. In summary, our study demonstrates that POSTN negatively regulates PPARα expression. Targeting POSTN-PPARα axis may present a novel protective intervention to alleviate CKD and CKD-associated cardiac dysfunction.