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

The proton channel Hvcn1 is expressed by T lymphocytes and regulates intracellular acidity.

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The proton channel Hvcn1 is expressed by T lymphocytes and regulates int...
T cells were purified from spleen and lymph nodes (LN) of WT mice and stimulated with plate-bound anti-CD3 (1 μg/mL) and anti-CD28 (5 μg/mL) with 20 U/mL IL-2 for the indicated number of days. Expression of Hvcn1 gene and protein was measured by quantitative PCR (qPCR) and Western blot in CD4+ and CD8+ T cell subsets (A and B, respectively). (C) LN T cells from WT and Hvcn1-deficient mice were stained with DAPI (blue), anti-CD3 (orange) and anti-Hvcn1 (red) Abs and visualized by confocal microscopy. Scale bar: 10 μm. (D and E) Total T cells and B cells were isolated from WT mice (n = 3) and the protein extract resolved by SDS gel electrophoresis. NADPH oxidase levels were normalized to GAPDH levels. (F and G) Relative pHi of naive (n)CD4+ and nCD8+ (n = 3, F) and Ab-activated (day 4, G) CD4+ and CD8+ (n = 6) WT and Hvcn1-deficient (KO) T cells was calculated by staining with pHRodo. Results are presented as mean ± SD. *P < 0.05, **P < 0.01, ***P < 0.005; 2-tailed Student’s t test.