Inhibition of miR‑155‑5p attenuates the valvular damage induced by rheumatic heart disease

Abstract

Autoimmunity is involved in the valvular damage caused by rheumatic heart disease (RHd). Increased evidence has linked microRNAs (miRNAs/miRs) to autoimmune disease. Signal transducer and activator of transcription 3 (STAT3) and sphingosine-1-phosphate receptor 1 (S1PR1) and suppressor of cytokine signaling 1 (SOcS1) have been widely studied for their roles in autoimmunity and inflammation. Thus, the current study aims to investigate the role played by miR-155-5p in RHd-induced valvular damage via the S1PR1, SOcS1/STAT3 and interleukin (IL)-6/STAT3 signaling pathways. An RHd rat model was induced by inactivated Group A streptococci and complete Freund's adjuvant. A recombinant adeno-associated virus (AAV-miR155-inhibitor) was used to inhibit the expression of miR-155-5p in the heart. Inflammation and fibrosis were assessed by hematoxylin and eosin staining and Sirius red staining. The expression of miR-155-5p in valvular tissues and serum exosomes was detected by reverse transcription-quantitative PcR. S1PR1, SOcS1, STAT3, phosphorylated STAT3, IL-6 and IL-17 protein expression was detected by western blotting and immunohistochemistry. The relationships between miR-155-5p and S1PR1 and SOcS1 were detected by dual luciferase assays. cytokine concentrations were measured by ELISA. The expression of miR-155-5p in valve tissues and serum exosomes was increased along with decreased S1PR1 and activated SOcS1/STAT3 signaling in the RHd model. The expression of IL-6 and IL-17 was increased in the valves and the serum. dual luciferase assays showed that miR-155-5p directly targeted S1PR1 and SOcS1. Inhibition of valvular miR-155-5p through AAV pretreatment increased S1PR1 expression and inhibited activation of the SOcS1/STAT3 signal pathway as a result of attenuated valvular inflammation and fibrosis as well as a decrease in IL-6 and IL-17 in the valves and serum. These results suggest that inhibition of miR-155-5p can reduce RHd-induced valvular damage via the S1PR1, SOcS1/STAT3 and IL-6/STAT3 signaling pathways.

The intervention of S1PR1/STAT3 signaling pathway by inhibiting the expression of STAT3 attenuates the valvular damage due to rheumatic heart disease

“…2A, 2B and 3A-C). These results indicate that the expression of S1PR1 is down-regulated in the RHD rat model, which is consistent with previous reports [16,17]. Inhibition of STAT3 by STAT3-siRNA decreased STAT3 mRNA expression, this result can be re ected in the comparison between STAT3-siRNA group and the other three groups (P < 0.05; Fig.…”

“…Immunohistochemistry was performed following a previous report [17] to analyse the valve tissues, which were stained for IL-6 (1:65; cat. no.…”

Intervening in the S1PR1/STAT3 Signaling Pathway Attenuates Valvular Damage Due to Rheumatic Heart Disease

“…In this study, we aimed to nd out whether altering S1PR1/STAT3 signaling pathway can attenuate the valvular damage caused by RHD. In order to achieve this goal, RHD rat model was established following previous reports [14,21,[26][27][28][29][30], overexpression sequence was used to overexpress the expression of S1PR1, the expression of STAT3 was inhibited by STAT3-siRNA, Th17 cell-related cytokines (IL-6 and IL-17) and transcription factor (RORγt) were detected. Then, the degree of in ammation and brosis in valve tissues was evaluated to nally verify our conjecture.…”

“…The RHD group was the established RHD model. The method we used to establish the RHD rat model was following previous reports [14,21,[26][27][28][29][30]. Footpad injection of CFA (Sigma-Aldrich, Merck KGaA) is essential in establishing the RHD rat model.…”

“…Immunohistochemistry was performed following a previous report [30] was re ected by brownish yellow staining, which was detected by microscopy. Quantitative assessment was performed using the methods provided by Friedrichs et al in a previous report [33].…”