RESUMEN
Background: Transient receptor potential melastatin 4 (TRPM4) affects immune responses by regulating calcium homeostasis, but its role in calcific aortic valve inflammation remains unclear. This study aimed to assess the expression and function of TRPM4 in patients with or without calcific aortic valve disease (CAVD). Methods: The mRNA and protein expression levels of TRPM4 and related factors in calcified and noncalcified tissues were measured using qRT-PCR and Western blot. The proteins interacting with TRPM4 were confirmed by RNA pull-down and RNA immunoprecipitation assays. Dual-Luciferase Reporter Assay was performed to confirm the m6A site of TRPM4. Results: The mRNA expression levels of TRPM4, TLR4, IL-6, MCP-1, TNF-α, and NF-κB p65 were significantly higher in calcified aortic valve tissues than in noncalcified tissues, and TRPM4 was significantly positively correlated with inflammation-related factors. The protein expression level of TRPM4, TLR4 and NF-κB p65 were significantly higher in calcified aortic valve tissues than in noncalcified tissues. N6-methyladenosine (m6A) modification of TRPM4 mRNA by METTL3-YTHDF1 up-regulated its expression in CAVD. And TRPM4 promoted the level of inflammation via activation of the JNK-MAPK signaling pathway, after knockdown TRPM4, the production of proinflammatory cytokines was significantly suppressed. Conclusion: The results indicate the pivotal role of TRPM4 in CAVD and highlight METTL3-mediated m6A modification of TRPM4 in promoting inflammation through JNK-MAPK signaling pathway. This work provides potential therapeutic strategy to impede inflammation in CAVD.
RESUMEN
MiR-6870-3p acts as a crucial regulator of gene expression at the posttranscriptional level and participates in immune responses. However, the roles of miR-6870-3p and its target genes and their underlying mechanisms in the inflammatory responses of epicardial adipose tissues (EATs) are unknown.MiRNA microarray was used to collect the miRNA expression profiles of EATs from five patients with coronary artery disease (CAD) and four individuals without CAD (n-CAD). Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to examine the expression of miR-6870-3p in the EATs. The mRNA and protein expression levels of Tollip and the key genes of the Toll-like receptor 4 (TLR4) signaling pathway were examined by qRT-PCR and Western blot analysis. The levels of inflammatory factors in the cell supernatant were measured by enzyme-linked immunosorbent assay (ELISA). We used a dual-luciferase reporter assay to validate the target gene of miR-6870-3p. The protein expression levels of c-Jun N-terminal kinase (JNK) and nuclear factor kappa B (NF-κB) were measured by Western blot analysis.Our results showed that miR-6870-3p was higher in the CAD EATs than in the n-CAD EATs. MiR-6870-3p was positively correlated with TLR4, interleukin (IL)-6, JNK, NF-κB (p65), and tumor necrosis factor (TNF)-α in the CAD EAT samples. Lipopolysaccharide (LPS) treatment upregulated the miR-6870-3p expression and downregulated the Tollip expression in the macrophages. When the macrophages were stimulated with LPS, MiR-6870-3p upregulation also aggravated the production of proinflammatory cytokines. The result of the luciferase reporter assays confirmed that miR-6870-3p directly targets Tollip. Moreover, miR-6870-3p upregulation in the macrophages resulted in the activation of the JNK/NF-κB pathway.Our study showed that miR-6870-3p regulates human EAT inflammation by targeting the Tollip-mediated JNK and NF-κB signaling pathways.
