LncRNA NKILA suppresses airway hyper reactivity via interfering the facilitation of MUC5AC and MUC5B mediated by GALNT2

Abstract

Glycosylation of mucins mediated by N-acetylgalactosaminyltransferases (GALNTs) is closely related to respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). In addition, long non-coding RNAs (LncRNAs) participate in physiological and pathological processes through various epigenetic mechanisms. In this study, we found that a novel LncRNA named NKILA combined with multiple mucins and GALNTs potentially by several bioinformatics methods, and we used quantitative real-time PCR (RT-qPCR) to detect the expressions of NKILA, MUC5AC, MUC5B, and GALNT2 mRNA in 50 cases of asthma samples and 19 cases of normal samples, whose results showed that the expression of NKILA was significantly decreased in asthmatic samples, negatively correlated with the severity of asthma and the expressions of MUC5AC and MUC5B, while GALNT2 was significantly increased in asthmatic tissues, and positively correlated with the severity of asthma and the expressions of MUC5AC and MUC5B. In vitro, we used transient transfection technology to overexpress or interfere with NKILA and GALNT2 and then detected the expressions of MUC5AC and MUC5B via RT-qPCR and Western blot, which demonstrated GALNT2 can promote the expressions of MUC5AC and MUC5B protein, while NKILA could inhibit this effect. Furthermore, co-immunoprecipitation results showed that GALNT2 could bind to MUC5AC and MUC5B protein. RNA immunoprecipitation and RNA pull-down experiments showed that NKILA could bind to GALNT2. These evidences suggested that there are correlations among the expression of NKILA, GALNT2, MUC5AC, and MUC5B proteins in asthmatic patients. Mechanically, we concluded that NKILA can suppress the O-linked glycosylation of MUC5AC and MUC5B proteins by binding to GALNT2 and inhibit the expression of MUC5AC and MUC5B proteins. Our researches provided a potential therapeutic target for AHR.