Lactate supports Treg function and immune balance via MGAT1 effects on N-glycosylation in the mitochondria
Jinren Zhou, … , Ling Lu, Bruce R. Blazar
Jinren Zhou, … , Ling Lu, Bruce R. Blazar
Published September 12, 2024
Citation Information: J Clin Invest. 2024;134(20):e175897. https://doi.org/10.1172/JCI175897.
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Research Article Immunology Metabolism

Lactate supports Treg function and immune balance via MGAT1 effects on N-glycosylation in the mitochondria

Abstract

Current research reports that lactate affects Treg metabolism, although the precise mechanism has only been partially elucidated. In this study, we presented evidence demonstrating that elevated lactate levels enhanced cell proliferation, suppressive capabilities, and oxidative phosphorylation (OXPHOS) in human Tregs. The expression levels of Monocarboxylate Transporters 1/2/4 (MCT1/2/4) regulate intracellular lactate concentration, thereby influencing the varying responses observed in naive Tregs and memory Tregs. Through mitochondrial isolation, sequencing, and analysis of human Tregs, we determined that α-1,3-Mannosyl-Glycoprotein 2-β-N-Acetylglucosaminyltransferase (MGAT1) served as the pivotal driver initiating downstream N-glycosylation events involving progranulin (GRN) and hypoxia-upregulated 1 (HYOU1), consequently enhancing Treg OXPHOS. The mechanism by which MGAT1 was upregulated in mitochondria depended on elevated intracellular lactate that promoted the activation of XBP1s. This, in turn, supported MGAT1 transcription as well as the interaction of lactate with the translocase of the mitochondrial outer membrane 70 (TOM70) import receptor, facilitating MGAT1 translocation into mitochondria. Pretreatment of Tregs with lactate reduced mortality in a xenogeneic graft-versus-host disease (GvHD) model. Together, these findings underscored the active regulatory role of lactate in human Treg metabolism through the upregulation of MGAT1 transcription and its facilitated translocation into the mitochondria.

Authors

Jinren Zhou, Jian Gu, Qufei Qian, Yigang Zhang, Tianning Huang, Xiangyu Li, Zhuoqun Liu, Qing Shao, Yuan Liang, Lei Qiao, Xiaozhang Xu, Qiuyang Chen, Zibo Xu, Yu Li, Ji Gao, Yufeng Pan, Yiming Wang, Roderick O’Connor, Keli L. Hippen, Ling Lu, Bruce R. Blazar

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Figure 3

Lactate promotes Treg metabolism by GRN N-glycosylation.

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Lactate promotes Treg metabolism by GRN N-glycosylation. (A) TregN was c...
(A) TregN was cultured in a regular and 20 mM lactate-treated environment for 48 hours, and the mitochondria were isolated to perform mitochondrial N-glycosylation mass spectrometry. Differential N-glycosylation peptides were shown by limma via Venn diagram. (B) Specific differential N-glycosylation peptides in regular and lactate-treated groups by limma via Volcano map. (C) Total 9 upregulated and 13 down-regulated N-glycosylation peptides in lactate treated group by heat map. (D) CRISPR/Cas9 gene editing technology was used in Jurkat to mutate the Asparagine at GRN N530 to Aspartic acid in vitro. (E) Mitochondrial morphology under the transmission electron microscope in 4 groups after 48 hours of culture: Jurkat, lactate-treated Jurkat, GRN N530D mutation Jurkat, and lactate with GRN N530D mutation Jurkat. Obvious mitochondria swelling and disruption of mitochondrial crests were observed under the transmission electron microscope in the mutation and lactate-treated mutation group. Scale bars: 1 μm and 500nm. (F) Mitochondrial injury scoring of 4 groups in (E). n = 3. (G) TMRM fluorescence signal intensity of Jurkat in (E). n = 3. (H) Mitochondrial to nuclear DNA (mtDNA: nDNA) ratio of 4 groups in (D). n = 3. Data are represented as mean ± SEM. 1-way ANOVA (G and H). *P < 0.05, **P < 0.01.