MiR-23a-3p alleviates cigarette smoke extract-induced pulmonary vascular endothelial cell apoptosis by targeting DNAJB1 in emphysema.

BACKGROUND: Cigarette smoke (CS) is an important risk factor for chronic obstructive pulmonary disease, including emphysema. MicroRNAs (miRNAs) are important regulators of emphysema progression. However, miR-23a-3p role in emphysema is unclear. METHODS: CS exposure was used to construct emphysema mice models, and cigarette smoke extract (CSE)-induced pulmonary vascular endothelial cells (PMVECs) were used to mimic emphysema cell models. Mouse lung tissue was stained by immunohistochemical staining, hematoxylin and eosin staining, and TUNEL staining. MiR-23a-3p and DnaJ homolog subfamily B member 1 (DNAJB1) levels were tested using quantitative real-time PCR. DNAJB1 and apoptosis-related markers' protein levels were examined via western blot analysis. Cell viability and apoptosis were analyzed by MTT assay and flow cytometry. The interaction between miR-23a-3p and DNAJB1 was evaluated by dual-luciferase reporter assay and RIP assay. RESULTS: MiR-23a-3p was downregulated, and DNAJB1 was upregulated in CS-induced emphysema mice models and CSE-induced PMVECs. MiR-23a-3p overexpression promoted viability and repressed apoptosis in CSE-induced PMVECs. MiR-23a-3p targeted DNAJB1 and negatively regulated DNAJB1 expression. Moreover, DNAJB1 knockdown repressed CSE-induced PMVECs apoptosis, and miR-23a-3p inhibitor reversed this effect. Additionally, miR-23a-3p alleviated lung tissue injury and improved emphysema in mice by reducing DNAJB1 expression. CONCLUSION: MiR-23a-3p alleviated emphysema progression, which could inhibit CSE-induced PMVECs apoptosis by targeting DNAJB1.

Lysyl hydroxylase 3 increases collagen deposition and promotes pulmonary fibrosis by activating TGFß1/Smad3 and Wnt/ß-catenin pathways.

INTRODUCTION: Lysyl hydroxylase 3 (LH3) is a collagen post-translational modifying enzyme; it is abnormally activated during the formation of collagen cross-links. iCRT3 is an inhibitor of both Wnt and ß-catenin responsive transcription. We hypothesized that LH3 is regulated by TGFß1/Smad3 signaling and Wnt/ß-catenin signaling pathways. Some evidence suggested that there is complicated cross-talk between the two signal pathways in the genesis of pulmonary fibrosis. MATERIAL AND METHODS: The normal culturing human lung cancer cell line A549 was derived from pulmonary epithelial cells. Transforming growth factor-ß1 (TGF-ß1) was induced A549 cells of pulmonary fibrosis. MTT assays detected cell growth stimulation by TGF-ß1; collagen pyridine-crosslinking contents were detected by ELISA kits. Immunofluorescence were used to evaluate expression of key molecules in PLOD3 (LH3), Wnt/ß-catenin and TGFß1/Smad3 pathways. RESULTS: Our findings suggested that iCRT3 could decrease LH3 protein expression (p < 0.01), Wnt1, ß-catenin and p-Smad3 protein expression (p < 0.05). Knock-down PLOD3 could decrease LH3, collagen I gene and protein expression (p < 0.05). These effects were associated with decreasing collagen pyridine-crosslinking production (p < 0.05). However, ovexpression PLOD3 could increase LH3, collagen I gene and protein expression (p < 0.05). The result showed that LH3 plays an important role in collagen post-translational modifications, and it is regulated by Wnt/ß-catenin and TGFß1/Smad3 pathways. CONCLUSIONS: This study suggests that PLOD3 (LH3) represents a target to prevent pulmonary fibrosis.