Intracellular localization of polymyxins in human alveolar epithelial cells.

ABSTRACT: Background:Current inhaled polymyxin therapy is empirical and often large doses are administered, which can lead to pulmonary adverse effects. There is a dearth of information on the mechanisms of polymyxin-induced lung toxicity and their intracellular localization in lung epithelial cells. Objectives:To investigate the intracellular localization of polymyxins in human lung epithelial A549 cells. Methods:A549 cells were treated with polymyxin B and intracellular organelles (early and late endosomes, endoplasmic reticulum, mitochondria, lysosomes and autophagosomes), ubiquitin protein and polymyxin B were visualized using immunostaining and confocal microscopy. Fluorescence intensities of the organelles and polymyxin B were quantified and correlated for co-localization using ImageJ and Imaris platforms. Results:Polymyxin B co-localized with early endosomes, lysosomes and ubiquitin at 24?h. Significantly increased lysosomal activity and the autophagic protein LC3A were observed after 0.5 and 1.0?mM polymyxin B treatment at 24?h. Polymyxin B also significantly co-localized with mitochondria (Pearson's R?=?0.45) and led to the alteration of mitochondrial morphology from filamentous to fragmented form (n?=?3, P?

SUBMITTER: Ahmed MU 

PROVIDER: S-EPMC6293086 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature