Impaired branched chain amino acid (BCAA) catabolism during adipocyte differentiation decreases glycolytic flux

Courtney R Green; Lynn M Alaeddine; Karl A Wessendorf-Rodriguez; Rory Turner; Merve Elmastas; Justin D Hover; Anne N Murphy; Mikael Ryden; Niklas Mejhert; Christian M Metallo; Martina Wallace

doi:10.1016/j.jbc.2024.108004

Impaired branched chain amino acid (BCAA) catabolism during adipocyte differentiation decreases glycolytic flux

J Biol Chem. 2024 Nov 15:108004. doi: 10.1016/j.jbc.2024.108004. Online ahead of print.

Affiliations

¹ Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd., La Jolla, CA, USA 92037; Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA 92093.
² Department of Medicine (Huddinge), Karolinska Institutet, ME Endokrinologi, Karolinska University Hospital Huddinge, Huddinge, Sweden.
³ School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
⁴ Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA 92093.
⁵ Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA 92093.
⁶ Department of Medicine (Huddinge), Karolinska Institutet, ME Endokrinologi, Karolinska University Hospital Huddinge, Huddinge, Sweden; Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark.
⁷ School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland. Electronic address: martina.wallace@ucd.ie.

PMID: 39551140
DOI: 10.1016/j.jbc.2024.108004

Abstract

Dysregulated branched chain amino acid (BCAA) metabolism has emerged as a key metabolic feature associated with the obese insulin resistant state, and adipose BCAA catabolism is decreased in this context. BCAA catabolism is upregulated early in adipogenesis, but the impact of suppressing this pathway on the broader metabolic functions of the resultant adipocyte remains unclear. Here, we use CRISPR/Cas9 to decrease BCKDHA in 3T3-L1 and human pre-adipocytes, and ACAD8 in 3T3-L1 pre-adipocytes to induce a deficiency in BCAA catabolism through differentiation. We characterize the transcriptional and metabolic phenotype of 3T1-L1 cells using RNAseq and ¹³C metabolic flux analysis within a network spanning glycolysis, tricarboxylic acid (TCA) metabolism, BCAA catabolism, and fatty acid synthesis. While lipid droplet accumulation is maintained in Bckdha-deficient adipocytes, they display a more fibroblast-like transcriptional signature. In contrast, Acad8 deficiency minimally impacts gene expression. Decreased glycolytic flux emerges as the most distinct metabolic feature of 3T3-L1 Bckdha-deficient cells, accompanied by a ∼40% decrease in lactate secretion, yet pyruvate oxidation and utilization for de novo lipogenesis are increased to compensate for loss of BCAA carbon. Deletion of BCKDHA in human adipocyte progenitors also led to a decrease in glucose uptake and lactate secretion, however these cells did not upregulate pyruvate utilisation and lipid droplet accumulation and expression of adipocyte differentiation markers was decreased in BCKDH knockout cells. Overall our data suggest that human adipocyte differentiation may be more sensitive to the impact of decreased BCKDH activity than 3T3-L1 cells, and that both metabolic and regulatory cross-talk exists between BCAA catabolism and glycolysis in adipocytes. Suppression of BCAA catabolism associated with metabolic syndrome may result in a metabolically compromised adipocyte.

Keywords: adipogenesis; adipose; branched chain amino acids; glycolysis; metabolic flux.