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 4

Mitochondrial function of TregN declines after MGAT1 knockdown.

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Mitochondrial function of TregN declines after MGAT1 knockdown. (A) Tran...
(A) Transfection efficiency of lentivirus in lactate with lentiviral vector and lactate with MGAT1 knockdown group for 3 days was shown by microscopy images in TregN. Scale bar: 100 μm. (B) Expression of MGAT1 mRNA in groups in A. n = 3. (C) Expression of MGAT1 in groups in A by Western blot. n = 3. (D) Representative FOXP3 MFI by flow cytometry in 4 groups: lentiviral vector, lactate with lentiviral vector, MGAT1 knockdown, and lactate with MGAT1 knockdown group for 3 days. (E) Inhibitory function of TregN in 4 groups in D on CD8+ T cell proliferation (CD8: TregN = 2:1) by flow cytometry. n = 3. (F) Representative TMRM fluorescence signal intensity by flow cytometry in 4 groups in D. (G) OCR of TregM in 4 groups in D via cell metabolism measurement (Seahorse 1034 assay). Data are represented as mean ± SEM. 2-tailed Student’s t test (B and C) or 1-way ANOVA (E–I). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.