Gandhi D, Bhandari S, Mishra S, Rudrashetti AP, Vetrivel U, Thimmulappa RK, Rajasekaran S. Forced expression of microRNA-221-3p exerts protective effects against manganese-induced cytotoxicity in human lung epithelial cells.
Toxicol Appl Pharmacol 2024;
485:116904. [PMID:
38503349 DOI:
10.1016/j.taap.2024.116904]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/11/2024] [Accepted: 03/15/2024] [Indexed: 03/21/2024]
Abstract
Manganese (Mn)-induced pulmonary toxicity and the underlying molecular mechanisms remain largely enigmatic. Further, in recent years, microRNAs (miRNAs) have emerged as regulators of several pollutants-mediated toxicity. In this context, our study aimed at elucidating whether miRNAs are involved in manganese (II) chloride (MnCl2) (Mn2+)-induced cytotoxicity in lung epithelial cells. Growth inhibition of Mn2+ towards normal human bronchial epithelial (BEAS-2B) and adenocarcinomic human alveolar basal epithelial (A549) cells was analyzed by MTT assay following 24 or 48 h treatment. Reactive oxygen species (ROS) generation, mitochondrial membrane potential (ΔΨm), cell cycle arrest, and apoptosis were evaluated by flow cytometry. RT-qPCR and Western blot were performed to analyze the expression of cyclins, anti-oxidant genes, and miRNAs. We used small RNA sequencing to investigate Mn2+-induced changes in miRNA expression patterns. In both cell lines, Mn2+ treatment inhibited growth in a dose-dependent manner. Further, compared with vehicle-treated cells, Mn2+ (250 μM) treatment induced ROS generation, cell cycle arrest, apoptosis, and decreased ΔΨm as well as altered the expression of cyclins and anti-oxidant genes. Sequencing data revealed that totally 296 miRNAs were differentially expressed in Mn2+-treated cells. Among them, miR-221-3p was one of the topmost down-regulated miRNAs in Mn2+-treated cells. We further confirmed this association in A549 cells. In addition, transient transfection was performed to study gain-of-function experiments. Forced expression of miR-221-3p significantly improved cell viability and reduced Mn2+-induced cell cycle arrest and apoptosis in BEAS-2B cells. In conclusion, miR-221-3p may be the most likely target that accounts for the cytotoxicity of Mn2+-exposed lung epithelial cells.
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