TNFSF14, a novel target of miR-326, facilitates airway remodeling in airway smooth muscle cells via inducing extracellular matrix protein deposition and proliferation.

As a common chronic respiratory disease, the incidence of asthma is increasing in recent years worldwide. Airway remodeling is the primary pathological basis of refractory asthma, but the studies about the underlying mechanism of airway remodeling was a lack. In the study, we aimed to investigate the effects and mechanisms of miR-326 on airway remodeling in airway smooth muscle cells (ASMCs). The results showed that transforming growth factor-ß1 (TGF-ß1) accelerated matrix protein deposition by increasing the expression levels of collagen I and fibronectin, and promoted proliferative ability of ASMCs. However, miR-326 was significantly downregulated in TGF-ß1-treated ASMCs. MiR-326 mimics robustly decreased the collagen I and fibronectin levels and inhibited cell proliferation of TGF-ß1-treated ASMCs. Luciferase assay investigated that tumor necrosis factor superfamily member 14 (TNFSF14) was a direct target of miR-326. The expression of TNFSF14 was negatively regulated by miR-326. Moreover, exogenous TNFSF14 effectively reversed the inhibitory effects of miR-326 overexpression on the expression levels of collagen I and fibronectin, and promoted cell proliferation of TGF-ß1-treated ASMCs. In conclusion, miR-326 suppressed matrix protein deposition and cell proliferation of TGF-ß1-treated ASMCs via inhibiting TNFSF14. MiR-326 might be a promising novel therapeutic target for asthma.

MicroRNA (miR)-429 Promotes Inflammatory Injury by Targeting Kruppel-like Factor 4 (KLF4) in Neonatal Pneumonia.

BACKGROUND: Neonatal pneumonia is a common disease in the neonatal period with a high incidence and death. This study aimed to investigate the molecular mechanism and effect of microRNA (miR)-429 in neonatal pneumonia. METHODS: The peripheral blood was collected from neonatal pneumonia and healthy patients, respectively. Human lung fibroblast WI-38 cells were treated with lipopolysaccharide (LPS) to establish neonatal pneumonia cell model. Then, the miR-429 expression was detected by quantitative real-time polymerase chain reaction (qRT-PCR). In addition, the relationship between miR- 429 and kruppel-like factor 4 (KLF4) was confirmed by dual luciferase reporter assay. Cell viability, the level of interleukin 6 (IL-6), IL-1ß and tumor necrosis factor α (TNF-α) and apoptosis were measured by Cell Counting Kit-8 (CCK-8), enzyme linked immunosorbent assay (ELISA) and flow cytometry. Meanwhile, apoptosis and nuclear factor kappa-B (NF-κB) pathway related proteins expression were analyzed by western blot. RESULTS: MiR-429 expression level was increased in neonatal peripheral blood and LPS-stimulated WI-38 cells. Then, miR-429 overexpression increased apoptosis, the level of IL-6, IL-1ß, TNF-α, Bax and cleaved caspase-3, while reduced cell viability in LPS-stimulated WI-38 cells. Besides, KLF4 was identified as the target gene of miR-429, and reversed the changes caused by miR-429 overexpression. Finally, miR-429 suppressor down-regulated p-NF-κB level in LPS-stimulated cells and KLF4 knockdown reversed these reductions. CONCLUSION: MiR-429 promotes inflammatory injury, apoptosis and activates the NF-κB signaling pathway by targeting KLF4 in neonatal pneumonia, and then these results provide evidence for clinical diagnosis and treatment for neonatal pneumonia.