Zinc transport from the endoplasmic reticulum to the cytoplasm via Zip7 is necessary for barrier dysfunction mediated by inflammatory signaling in RPE cells

YongYao Xu; Michael Twarog; Ning Li; Angela Banks; Josh Schustak; Yi Bao; Qian Huang; Quintus G Medley

doi:10.1371/journal.pone.0271656

Zinc transport from the endoplasmic reticulum to the cytoplasm via Zip7 is necessary for barrier dysfunction mediated by inflammatory signaling in RPE cells

PLoS One. 2022 Jul 28;17(7):e0271656. doi: 10.1371/journal.pone.0271656. eCollection 2022.

Authors

YongYao Xu¹, Michael Twarog¹, Ning Li¹, Angela Banks¹, Josh Schustak¹, Yi Bao¹, Qian Huang¹, Quintus G Medley¹

Affiliation

¹ Department of Ophthalmology, Novartis Institutes of Biomedical Research, Cambridge, MA, United States of America.

Abstract

Inflammatory signaling induces barrier dysfunction in retinal-pigmented epithelium (RPE) cells and plays a role in the pathology of age-related macular degeneration (AMD). We studied the role of Zn flux from the endoplasmic reticulum (ER) to the cytoplasm via Zip7 during inflammatory signaling in RPE cells. In ARPE-19 cells, Zip7 inhibition reduced impedance loss, FITC-dextran permeability and cytokine induction caused by challenge with IL-1β/TNF-α. Zip7 inhibition in iPS-derived RPE cells challenged with TNF- α reduced barrier loss in TER assays. In ARPE-19 cells, a Zn ionophore restored cytokine induction and barrier loss in cells challenged with IL-1 β /TNF- α despite Zip7 inhibition. A cell permeable Zn chelator demonstrated that Zn is essential for IL-1 β /TNF- α signaling. ER stress caused by Zip7 inhibition in ARPE-19 cells was found to partially contribute to reducing barrier dysfunction caused by IL-1 β /TNF- α. Overall, it was shown that Zn flux through Zip7 from the ER to the cytoplasm plays a critical role in driving barrier dysfunction caused by inflammatory cytokines in RPE cells.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cation Transport Proteins*
Cytokines
Endoplasmic Reticulum Stress
Endoplasmic Reticulum* / metabolism
Interleukin-1beta / pharmacology
Retinal Pigment Epithelium / metabolism
Tumor Necrosis Factor-alpha / pharmacology
Zinc / metabolism

Substances

Cation Transport Proteins
Cytokines
Interleukin-1beta
Tumor Necrosis Factor-alpha
Zinc

Grants and funding

All authors were employees of Novartis at the Novartis Institutes for Biomedical Research when this research was conducted. No specific funds were allocated for this study but all salaries and materials for this study were funded by Novartis as part of our regular job duties. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.