LncRNA OIP5-AS1 knockdown is associated with attenuated nonylphenol-induced cardiac fibrosis.

Abstract

Background: Environmental endocrine disruptors (EEDs), endocrine-interfering pollutants, attract attention for potentially affecting heart diseases via epigenetics. Nonylphenol (NP), a classical representative of endocrine-disrupting chemicals, has previously been demonstrated by our research group to induce myocardial fibrosis in rats. LncRNA, a gene regulator, mediates EED-induced heart cell damage and fibrosis.

Objective: This study aimed to investigate the role of long noncoding RNA OIP5 antisense RNA 1 (lncRNA OIP5-AS1) knockdown in NP-induced myocardial fibrosis.

Methods: Small interfering RNA (siRNA) transfection was used to interfere with the expression of lncRNA OIP5-AS1 in H9C2 cells. Lactate dehydrogenase (LDH), cell Counting Kit-8 (CCK-8), transwell, quantitative real time polymerase chain reaction (qRT-PCR), and Western blot assays were employed to detect cell membrane integrity, proliferation, migration ability, and the expression of fibrosis-related genes/proteins in H9C2 cells. This process was also validated in Sprague Dawley (SD) rats.

Results: The expression of fibrosis-related factor mRNA and proteins in H9C2 cells increased, and the expression of lncRNA OIP5-AS1 was significantly upregulated after 24 h of exposure to 70 µmol/L NP. The knockdown of lncRNA OIP5-AS1 did not show differential changes in LDH activity across treatment groups. However, the knockdown of lncRNA OIP5-AS1 significantly attenuated NP-induced proliferation and migration abilities of H9C2 cells and inhibited the increase in the expression of fibrosis-related factor mRNA/proteins caused by NP. This suggested that the interference with lncRNA OIP5-AS1 expression inhibited the NP-induced myocardial fibrosis in H9C2 cells. In vivo results suggested that NP exposure and isoproterenol hydrochloride groups in rats showed accumulation of myocardial collagen fibers in the interstitial space, increased distribution and content of collagen fibers, and elevated expression of fibrosis-related proteins. The distribution range, content of collagen fibers, and expression of fibrosis-related proteins significantly reduced in rats with lncRNA OIP5-AS1 knockdown exposed to NP compared with those in the NP group.

Conclusions: The expression of lncRNA OIP5-AS1 was upregulated in NP-treated H9C2 cells, rat hearts, and myocardial fibrosis model rats. Knockdown of lncRNA OIP5-AS1 was associated with attenuated NP-induced myocardial fibrosis and reduced collagen deposition.