Phagosomal chloride dynamics in the alveolar macrophage

Vladimir Riazanski; Gerardo Mauleon; Adriana M Zimnicka; Si Chen; Deborah J Nelson

doi:10.1016/j.isci.2021.103636

Phagosomal chloride dynamics in the alveolar macrophage

iScience. 2021 Dec 16;25(1):103636. doi: 10.1016/j.isci.2021.103636. eCollection 2022 Jan 21.

Authors

Vladimir Riazanski¹, Gerardo Mauleon¹, Adriana M Zimnicka¹, Si Chen², Deborah J Nelson¹

Affiliations

¹ The University of Chicago, Department of Pharmacological and Physiological Sciences, 947 E. 58th Street, MC 0926, Chicago, IL 60637, USA.
² X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.

Abstract

Acidification in intracellular organelles is tightly linked to the influx of Cl^- counteracting proton translocation by the electrogenic V-ATPase. We quantified the dynamics of Cl^- transfer accompanying cargo incorporation into single phagosomes in alveolar macrophages (AMs). Phagosomal Cl^- concentration and acidification magnitude were followed in real time with maximal acidification achieved at levels of approximately 200 mM. Live cell confocal microscopy verified that phagosomal Cl^- influx utilized predominantly the Cl^- channel CFTR. Relative levels of elemental chlorine (Cl) in hard X-ray fluorescence microprobe (XFM) analysis within single phagosomes validated the increase in Cl^- content. XFM revealed the complex interplay between elemental K content inside the phagosome and changes in Cl^- during phagosomal particle uptake. Cl^- -dependent changes in phagosomal membrane potential were obtained using second harmonic generation (SHG) microscopy. These studies provide a mechanistic insight for screening studies in drug development targeting pulmonary inflammatory disease.

Keywords: Biological sciences; Cell biology; Specialized functions of cells.