Long non-coding RNA growth arrest specific-5: a potential biomarker for early diagnosis of severe asthma

Abstract

Background: The diagnosis of severe asthma (SA) is difficult due to a necessary long-term treatment history currently, while there are few studies on biomarkers in the diagnosis of SA. Long non-coding RNA (lncRNA) growth arrest specific-5 (GAS5) has the potential of playing this role because its binding with glucocorticoid receptor (GR). The purpose of this article is to explore the possibility of lncRNA GAS5 acting as a biomarker for early diagnosis of severe asthma (SA).Methods: Peripheral blood was obtained from healthy volunteers, patients with non-severe asthma (nSA) and SA, and peripheral blood mononuclear cells (PBMCs) were separated. Twenty-four female BALB/ c mice (aged 6 weeks) were randomly and averagely divided into 3 groups, i.e., control group, asthma group and dexamethasone group. The mice were sensitized and challenged with ovalbumin (OVA) and lipopolysaccharide (LPS) to establish a murine model of steroid-insensitive asthma. Human bronchial epithelial cells (HBECs) were cultured, transfected with miR-9 mimics, JNK1 inhibitor and treated with interleukin (IL)-2 + IL-4 and dexamethasone. Western blot was used to detect glucocorticoid receptor phosphorylation at serine 226 (GR ser226 ), and quantitative real-time PCR was used to detect GAS5 level. Results:The level of GAS5 in PBMCs from nSA group elevated 20-fold higher after dexamethasone treatment in vitro, while it reduced 15-fold lower in SA group (P<0.001). The expression of GR ser226 in PBMCs from SA group was significantly higher than that from control group and nSA group after dexamethasone treatment (P<0.001). In the lung tissue of mice, the GAS5 level of dexamethasone group was lower than that of asthma group (P<0.001) and control group (P<0.05). Both treatment with IL-2 + IL-4 and transfection of miR-9 mimics could increase the expression of GR ser226 in HBECs (P<0.001). The GAS5 level in HBECs after IL-2 + IL-4 + Dexamethasone treatment was lower than that in HBECs only treated with IL-2 + IL-4 (P<0.001). Similarly, dexamethasone treatment also decreased the level of GAS5 in HBECs transfected with miR-9 mimics (P<0.05). Moreover, transfecting with JNK1 inhibitor could reverse the expression of GAS5 in HBECs transfected with miR-9 mimics and treated with dexamethasone. However, the level of GAS5 in HBECs interfered with IL-2 + IL-4 + Dexamethasone was not affected by JNK1 inhibitor. Conclusions:The expression of GAS5 is different in PBMCs between nSA and SA, and is affected by glucocorticoids treatment, which is due to GR ser226 phosphorylation. GAS5 can be used as a potential biomarker for diagnosis of severe asthma by comparing GAS5 level in PBMCs from patients before and after glucocorticoids treatment in vitro.

Long Noncoding RNAs in the Regulation of Asthma: Current Research and Clinical Implications

“…LncRNA KCNQ1OT1 was correlated with the number of fibroblasts and functioned as a predictor of airway remodeling. Wu et al (2020) confirmed that lncRNA growth arrest specific-5 (GAS5) expressed differentially in PBMCs between nonsevere asthmatic patients and severe asthmatic patients. To further explore its mechanism, it was found that GAS5 could bind to the glucocorticoid receptor and affect its phosphorylation at serine 226 in human bronchial epithelial cells (HBECs) in vitro.…”

Knockdown of long noncoding RNA growth arrest‐specific transcript 5 regulates forkhead box O3 to inhibit lipopolysaccharide‐induced human bronchial epithelial cell pyroptosis

“…Li et al have reported that GAS5 expression increased in PM2.5‐induced HBECs 13 . Similarly, a recent study indicated that GAS5 level was higher in peripheral blood mononuclear cells from asthma patients compared with patients with nonsevere asthma 14 . Moreover, pro‐inflammatory mediators could increase GAS5 expression in airway smooth muscle and epithelial cells 11 .…”

“…Consistent with our results, Li et al revealed that silencing of FOXO3 inhibited NLRP3‐mediated pyroptosis in human aortic endothelial cells after treatment with oxidized low‐density lipoprotein. 14 In addition, FOXO3 inhibition abrogates inflammation and apoptosis of LPS‐induced alveolar epithelial cells, 36 which activates the Nrf2/HO‐1 pathway to inhibit LPS‐induced pyroptosis in human gingival fibroblasts 23 . An interaction between FOXO3 and the Nrf2/HO‐1 pathway could be inferred because FOXO3 is reported to directly interact with the promoter of Keap1 to inhibit the Nrf2 signaling pathway 37 .…”

“…Similarly, GAS5 is reported to promote airway smooth muscle cell proliferation in asthma 12 . Most importantly, GAS5 is upregulated in PM2.5‐induced HBECs 13 and in an HBEC model of severe asthma 14 . However, the role of GAS5 in HBEC pyroptosis remains largely unknown.…”

Unlocking the secrets of long non-coding RNAs in asthma

“…Multiple studies have looked at the possible function and potential of GAS5. [61][62][63] Wu et al found increased expression of GAS5 in peripheral blood of patients with severe and non-severe asthma compared with healthy controls. 63 GAS5 expression reduced after treatment with dexamethasone, a synthetic glucocorticosteroid, in a mouse model of steroid-insensitive asthma.…”