Background: Advances in the understanding of cardiovascular pathogenesis have highlighted that inflammation plays a central role in atherosclerotic coronary heart disease. Therefore, exploring pharmacologically based anti-inflammatory treatments to be used in cardiovascular therapeutics is worthwhile to promote the discovery of novel ways of treating cardiovascular disorders.
Methods: The myocardial cell line H9c2(2-1) was exposed to lipopolysaccharide (LPS) in culture and resulted in a cellular pro-inflammation status. miR-21 microRNA levels were detected using quantitative real-time polymerase chain reaction (Q-RT-PCR). The influence of lovastatin on miR-21 under normal and pro-inflammatory conditions was tested after being added to the cell culture mixture for 24 hours. Conditional gene function of two predicted cardiovascular system relevant downstream targets of miR-21, protein phosphatase 1 regulatory subunit 3A (PPP1R3A) and signal transducer and activator of transcription 3 (STAT3), were analyzed with immunoblotting.
Results: Forty-eight hours of LPS treatment significantly increased the miR-21 to 170.71%± 34.32% of control levels (P = 0.002). Co-treatment with lovastatin for 24 hours before harvesting attenuated the up-regulation of miR-21 (P = 0.013). Twenty-four hours of lovastatin exposure up-regulated PPP1R3A to 143.85%± 21.89% of control levels in cardiomyocytes (P = 0.023). Lovastatin up-regulated the phosphorylation level of STAT3 compared to the background LPS pretreatment (P = 0.0077), this effect was significantly (P = 0.018) blunted when miR-21 was functionally inhibited.
Conclusions: miR-21 plays a major role in the regulation of the cellular anti-inflammation effects of lovastatin.