Multiomic analysis reveals a key BCAT1 role in mTOR activation by B cell receptor and TLR9
Rui Guo, Yizhe Sun, Matthew Y. Lim, Hardik Shah, Joao A. Paulo, Rahaman A. Ahmed, Weixing Li, Yuchen Zhang, Haopeng Yang, Liang Wei Wang, Daniel Strebinger, Nicholas A. Smith, Meng Li, Merrin Man Long Leong, Michael Lutchenkov, Jin Hua Liang, Zhixuan Li, Yin Wang, Rishi Puri, Ari Melnick, Michael R. Green, John M. Asara, Adonia E. Papathanassiu, Duane R. Wesemann, Steven P. Gygi, Vamsi K. Mootha, Benjamin E. Gewurz
Rui Guo, Yizhe Sun, Matthew Y. Lim, Hardik Shah, Joao A. Paulo, Rahaman A. Ahmed, Weixing Li, Yuchen Zhang, Haopeng Yang, Liang Wei Wang, Daniel Strebinger, Nicholas A. Smith, Meng Li, Merrin Man Long Leong, Michael Lutchenkov, Jin Hua Liang, Zhixuan Li, Yin Wang, Rishi Puri, Ari Melnick, Michael R. Green, John M. Asara, Adonia E. Papathanassiu, Duane R. Wesemann, Steven P. Gygi, Vamsi K. Mootha, Benjamin E. Gewurz
View: Text | PDF
Research Article Cell biology Metabolism

Multiomic analysis reveals a key BCAT1 role in mTOR activation by B cell receptor and TLR9

Abstract

B lymphocytes play major adaptive immune roles, producing antibodies and driving T cell responses. However, how immunometabolism networks support B cell activation and differentiation in response to distinct receptor stimuli remains incompletely understood. To gain insights, we systematically investigated acute primary human B cell transcriptional, translational, and metabolomic responses to B cell receptor (BCR), TLR9, CD40-ligand (CD40L), IL-4, or combinations thereof. T cell–independent BCR/TLR9 costimulation, which drives malignant and autoimmune B cell states, highly induced transaminase branched chain amino acid transaminase 1 (BCAT1), which localized to lysosomal membranes to support branched chain amino acid synthesis and mTORC1 activation. BCAT1 inhibition blunted BCR/TLR9, but not CD40L/IL-4–triggered B cell proliferation, IL-10 expression, and BCR/TLR pathway–driven lymphoma xenograft outgrowth. These results provide a valuable resource, reveal receptor-mediated immunometabolism remodeling to support key B cell phenotypes, and identify BCAT1 as an activated B cell therapeutic target.

Authors

Rui Guo, Yizhe Sun, Matthew Y. Lim, Hardik Shah, Joao A. Paulo, Rahaman A. Ahmed, Weixing Li, Yuchen Zhang, Haopeng Yang, Liang Wei Wang, Daniel Strebinger, Nicholas A. Smith, Meng Li, Merrin Man Long Leong, Michael Lutchenkov, Jin Hua Liang, Zhixuan Li, Yin Wang, Rishi Puri, Ari Melnick, Michael R. Green, John M. Asara, Adonia E. Papathanassiu, Duane R. Wesemann, Steven P. Gygi, Vamsi K. Mootha, Benjamin E. Gewurz

×

Figure 2

Cross-comparison of αIgM + CpG versus CD40/IL-4–driven B cell metabolism remodeling.

Options: View larger image (or click on image) Download as PowerPoint
Cross-comparison of αIgM + CpG versus CD40/IL-4–driven B cell metabolism...
(A) Gene ontology (GO) biological process analysis of genes differentially expressed in B cells stimulated with αIgM + CpG versus CD40L + IL-4, using a curated metabolism gene set (34). (B) GSEA Hallmark pathway analysis of oxidative phosphorylation (top) and hypoxia genes in CD differentially expressed genes in B cells stimulated with αIgM + CpG versus CD40L + IL-4. (C) Heatmap analysis of mRNA encoding electron transport chain (ETC) components in cells stimulated as indicated. Columns display z score values for each ETC gene, produced by cross-comparison of the 10 conditions. (D) Seahorse oxygen consumption rate (OCR, top) and extracellular acidification rate (ECAR, bottom) of primary B cells stimulated by indicated conditions for 24 hours and subject to flux analysis in the presence of indicated ETC inhibitors. Mean ± SEM from n = 7 replicates shown. P values calculated by 2-way ANOVA. (E) FACS analysis of primary B cell glucose analogue 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose uptake at the indicated time points after stimulation. Mean ± SEM from n = 3 replicates. P values calculated by 2-tailed paired Student’s t test. (F) Heatmap analysis showing intracellular metabolite z scores in primary human B cells stimulated for 24 hours as indicated. (G) Volcano plot visualization of –log10 (P value statistical significance) versus log2 (fold-change metabolite abundance) from primary B cells stimulated by αIgM + CpG versus CD40L + IL-4 for 24 hours from n = 3 replicates. (H) MetaboAnalyst pathway enrichment analysis of metabolites that were higher in αIgM + CpG–stimulated cells than CD40L + IL-4–stimulated cells at 24 hours.