Suppression of microRNA-384 enhances autophagy of airway smooth muscle cells in asthmatic mouse

Abstract

Injury to airway smooth muscle (ASM) cells hallmarks the pathological progression of asthma, a chronic inflammatory airway disease. MicroRNAs (miRNAs) play essential roles in the development of asthma as well as airway remodeling. Here we studied the involvement of miRNAs in the regulation of autophagic survival of ASM cells and airway disorder. We analyzed autophagy-associated factors LC3 and Beclin-1 by RT-qPCR and protein blotting in purified airway smooth muscle cells from ovalbumin (OVA)-induced asthmatic mice. The biological activity of miRNA targeting Beclin-1 was explored by bioinformatics method and confirmed in a dual luciferase reporter assay. Loss of function experiment was performed via transplantation of miRNA in OVA-induced asthmatic mice. We detected high autophagy levels in ASM cells, which appeared to result from augmentation of Beclin-1 protein, rather than Beclin-1 mRNA, suggesting presence of post-transcriptional control of Beclin-1. Next, miR-384 was figured out to be a Belcin-1-targeting miRNA, which significantly decreased after OVA treatment. Mechanistically, binding of miR-384 to 3’-UTR of Beclin-1 mRNA potently suppressed Beclin-1 protein translation in ASM cells, similar to previous finding in another cell type. In vivo, transplantation of miR-384 significantly attenuated Belcin-1 protein levels in ASM cells, resulting in reduced autophagy of ASM cells and attenuation of asthmatic features by OVA. Together, these data suggest that re-expression of miR-384 may reduce augmentation of Beclin-1-dependent autophagy of ASM cells, as a novel promising treatment for asthma.

Augmented Pla2g4c/Ptgs2/Hpgds axis in bronchial smooth muscle tissues of experimental asthma

“…It has also been demonstrated that an inhibition of negative regulation mediated by a microRNA (miRNA), miR-133a-3p, is the main cause of the up-regulation of RhoA protein [ 18 , 45 ]. Similarly, miRNA regulation of airway smooth muscle function has also been reported [ 37 , 46 – 50 ]. It is thus possible that changes in post-transcriptional rather than transcriptional modulations of the gene expression might be largely involved in the alteration of smooth muscle contractility of the diseased airways.…”

Suppression of sirtuin 1 alleviates airway inflammation through mTOR‑mediated autophagy

“…during autophagy the cytoplasmic form lc3-i is processed and recruited to autophagosomes, where lc3-ii is generated by site-specific proteolysis near the C-terminus (24). The ratio of lc3-ii to lc3-i is commonly used to analyze autophagic activity, of which Beclin-1 is also considered a hallmark (17). Furthermore, it has been reported that autophagy suppression may inhibit airway inflammation in allergic mice (16).…”

Autophagy induces eosinophil extracellular traps formation and allergic airway inflammation in a murine asthma model

“…A characteristic feature of autophagy is the presence of autophagosomes. LC3 is a protein needed for autophagosome formation and is an indicator of autophagosome (Cheng et al, ). Ban et al () observed an increase in immunocontent of LC3‐II in sputum granulocytes from patients with severe asthma.…”