MicroRNA-33 Regulation Of THP-1 Macrophages Inflanmatory Responses And The Underlying Mechanism

Micro RNAs(mi RNAs) are a class of small non-coding RNA molecules derived from 18 to 25 nucleotides. It is incorporated by specific base pairing to the target gene m RNA 3’UTR(untranslated region), which induction of target gene m RNA degradation or inhibiting its translation. It is regulate gene expressionin the post-transcriptional level. Previous studies have shown that mi R-33 a can be silence ABCA1 expression combined by targeting ABCA1 and inhibition of cholesterol efflux mediated by apo A-Ⅰ. However, mi R-33 is able to negatively regulate LPS(lipopolysaccharide) induced THP-1 macrophage inflammatory response is still poorly understood, it remains to be studied.Based on the above background, we established inflammatory model by LPS stimulation of THP-1 macrophage. The first study of mi R-33 in the regulation of the inflammatory response in the role aims to clarify: mi R-33 is involved in the regulation of THP-1 macrophage inflammatory response and related mechanisms.Part-one: First, we examined the expression of mi R-33 in LPS-induced activation of THP-1 macrophages.The results showed thatLPS induced THP-1 macrophage activation was significantly up-regulated expression of mi R-33. With increasing concentration of LPS, the expression of mi R-33 gradually increases. This shows that its effect having a LPS concentration dependent and when the role of 10 ng / ml LPS in the most significant change. We upregulated or downregulated the expression level of mi R-33 through the mature mi R-33 mimics(mi R-33 mimics) repressor and mi R-33(mi R-33 inhibitor) was introduced into the macrophage cells. The results show that, mi R-33 may negatively regulates LPS-induced activation of THP-1 macrophage inflammatory response.Part-two: However, mi R-33 negatively regulates the expression of THP-1 macrophage inflammatory mediators is not clear. We found NRIP1 the 3’UTR region contains binding sites for mi R-33 through Targetscan and Mi RDB software forecast. NRIP1 as a transcriptional co-repressor factor through activation of nuclear factor κB(nuclear factor kappa B, NF-κB) signaling pathway, thereby regulating the expression of inflammatory cytokines. Therefore, we NRIP1 as an entry point to explore the regulatory mechanism mi R-33 on LPS-stimulated THP-1macrophage inflammatory response. By dual luciferase reporter gene technology found: mi R-33 can effectively inhibit binding sequence NRIP1 the 3’UTR luciferase reporter plasmid activity. In addition, we used RT-PCR and immunoblotting(western blot) method found thatNRIP1 m RNA and protein levels of expression in transfected mi R-33 mimics cells was significantly inhibited. We can conclude that mi R-33 by interacting with NRIP1 the 3’UTR, thereby inhibiting protein expression and ultimately inhibit activation NRIP1 signaling pathway.Conclusions:mi R-33 inhibition of LPS-induced THP-1 macrophage inflammatory cytokine secretion and negative regulation of THP-1 macrophage inflammatory responses by targeting the 3’UTR NRIP1 to inhibit the activation of signaling pathways NRIP1.