Loss of voltage-gated hydrogen channel 1 expression reveals heterogeneous metabolic adaptation to intracellular acidification by T cells
David Coe, … , Melania Capasso, Federica M. Marelli-Berg
David Coe, … , Melania Capasso, Federica M. Marelli-Berg
Published April 26, 2022
Citation Information: JCI Insight. 2022;7(10):e147814. https://doi.org/10.1172/jci.insight.147814.
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Research Article Immunology

Loss of voltage-gated hydrogen channel 1 expression reveals heterogeneous metabolic adaptation to intracellular acidification by T cells

Abstract

Voltage-gated hydrogen channel 1 (Hvcn1) is a voltage-gated proton channel, which reduces cytosol acidification and facilitates the production of ROS. The increased expression of this channel in some cancers has led to proposing Hvcn1 antagonists as potential therapeutics. While its role in most leukocytes has been studied in depth, the function of Hvcn1 in T cells remains poorly defined. We show that Hvcn1 plays a nonredundant role in protecting naive T cells from intracellular acidification during priming. Despite sharing overall functional impairment in vivo and in vitro, Hvcn1-deficient CD4+ and CD8+ T cells display profound differences during the transition from naive to primed T cells, including in the preservation of T cell receptor (TCR) signaling, cellular division, and death. These selective features result, at least in part, from a substantially different metabolic response to intracellular acidification associated with priming. While Hvcn1-deficient naive CD4+ T cells reprogram to rescue the glycolytic pathway, naive CD8+ T cells, which express high levels of this channel in the mitochondria, respond by metabolically compensating mitochondrial dysfunction, at least in part via AMPK activation. These observations imply heterogeneity between adaptation of naive CD4+ and CD8+ T cells to intracellular acidification during activation.

Authors

David Coe, Thanushiyan Poobalasingam, Hongmei Fu, Fabrizia Bonacina, Guosu Wang, Valle Morales, Annalisa Moregola, Nico Mitro, Kenneth C.P. Cheung, Eleanor J. Ward, Suchita Nadkarni, Dunja Aksentijevic, Katiuscia Bianchi, Giuseppe Danilo Norata, Melania Capasso, Federica M. Marelli-Berg

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Figure 5

Hvcn1 is expressed by mitochondria and regulates mitochondrial electron transport chain.

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Hvcn1 is expressed by mitochondria and regulates mitochondrial electron ...
(A and B) Purified naive CD8+ WT and Hvcn1-deficient T cells were Ab-activated for 4 days, then lysed and fractionated into Cytoplasmic/Membrane (C/Me), mitochondrial (M), and nuclear (N) and were then analyzed by Western blot for the presence of Hvcn1, Hsp60, and Gapdh proteins. (C) Naive WT and Hvcn1-deficient CD8+ T cells were incubated with or without FCCP for 5 minutes before being stained with DHE and analyzed by flow cytometry. The mean percentage of DHE+ T cells is shown (± SD, n = 4). (D and E) Total DNA was isolated from naive and Ab-activated (4 days) WT and Hvcn1-deficient CD8+ T cells (n = 3–4). Quantitative PCR was used to assess expression of mitochondrial genes 16s and Nd1 and normalized to the nuclear gene Hk2 to calculate mitochondrial DNA copy number. Data are presented as mean ± SEM (n = 5). Student’s 2-tailed t test; *P < 0.05, ***P < 0.005. (F) MMP of naive WT and Hvcn1-deficient CD8+ T cells was determined using MitoTracker Red (MitoRed). A representative histogram is shown on the right-hand side. Bar charts show mean MFI ± SD (n = 3). Data are presented as mean ± SD (n = 5). Student’s 2-tailed t test; ***P < 0.005.