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Fine particulate matter (PM 2.5) is a risk factor for pulmonary diseases and lung cancer, and inhaled PM 2.5 is mainly deposited in the bronchial epithelium. In this study, we investigated the effect of long-term exposure to low-dose PM 2.5 on BEAS-2B cells derived from the normal bronchial epithelium. BEAS-2B cells chronically exposed to a concentration of 5 µg/ml PM 2.5 for 30 passages displayed the phenotype promoting epithelial-mesenchymal transition (EMT) and cell invasion. Cellular internalization of exosomes (designated PM 2.5 Exo) extracted from BEAS-2B cells chronically exposed to low-dose PM 2.5 promoted cell invasion in vitro and metastatic potential in vivo. Hence, to identify the key players driving phenotypic alterations, we analyzed microRNA (miRNA) expression profiles in PM 2.5 Exo. Five miRNAs with altered expression were selected: miRNA-196b-5p, miR-135a-2–5p, miR-3117–3p, miR-218–5p, and miR-497–5p. miR-196b-5p was the most upregulated in both BEAS-2B cells and isolated exosomes after PM 2.5 exposure. In a functional validation study, genetically modified exosomes overexpressing a miR-196b-5p mimic induced an enhanced invasive phenotype in BEAS-2B cells. Conversely, miR-196b-5p inhibition diminished the PM 2.5 -enhanced EMT and cell invasion. These findings indicate that exosomal miR-196b-5p may be a candidate biomarker for predicting the malignant behavior of the bronchial epithelium and a therapeutic target for inhibiting PM 2.5 -triggered pathogenesis. • Exosomes from BEAS-2B cells chronically exposed to low-dose PM 2.5 promote the invasiveness of adjacent cells. • Exosomal miR-196b-5p may predict and trigger the malignant behavior of adjacent cells. • Exosomes harboring the miR-196b-5p inhibitor may suppress PM2.5-triggered pathogenesis. [ABSTRACT FROM AUTHOR]

Endometrial receptivity is essential for successful embryo implantation and pregnancy initiation and is regulated via various signaling pathways. Adiponectin, an important adipokine, may be a potential regulator of reproductive system functions. The aim of the present study was to elucidate the regulatory role of adiponectin receptor 1 (ADIPOR1) in endometrial receptivity. The endometrial receptivity between RL95-2 and AN3CA cell lines was confirmed using an in vitro JAr spheroid attachment model. 293T cells were transfected with control or short hairpin (sh)ADIPOR1 vectors and RL95-2 cells were transduced with lentiviral particles targeting ADIPOR1. Reverse transcription-quantitative PCR and immunoblot assays were also performed. ADIPOR1 was consistently upregulated in the endometrium during the mid-secretory phase compared with that in the proliferative phase and in receptive RL95-2 cells compared with that in non-receptive AN3CA cells. Stable cell lines with diminished ADIPOR1 expression caused by shRNA showed reduced E-cadherin expression and attenuated in vitro endometrial receptivity. ADIPOR1 regulated AMP-activated protein kinase (AMPK) activity in endometrial epithelial cells. Regulation of AMPK activity via dorsomorphin and 5-aminoimidazole-4-carboxamide ribonucleotide affected E-cadherin expression and in vitro endometrial receptivity. The ADIPOR1/AMPK/E-cadherin axis is vital to endometrial receptivity. These findings can help improve fertility treatments and outcomes. [ABSTRACT FROM AUTHOR]