Bone marrow adipocytes drive the development of tissue invasive Ly6Chigh monocytes during obesity
- Hospital for Sick Children, Canada
- University of Toronto, Canada
- Toronto General Hospital, Canada
Abstract
During obesity and high fat-diet (HFD) feeding in mice, sustained low-grade inflammation includes not only increased pro-inflammatory macrophages in the expanding adipose tissue, but also bone marrow (BM) production of invasive Ly6Chigh monocytes. As BM adiposity also accrues with HFD, we explored the relationship between the gains in BM white adipocytes and invasive Ly6Chigh monocytes in vivo and through ex vivo paradigms. We find a temporal and causal link between BM adipocyte whitening and the Ly6Chigh monocyte surge, preceding the adipose tissue macrophage rise during HFD. Phenocopying this, ex vivo treatment of BM cells with conditioned media from BM adipocytes or from bona fide white adipocytes favoured Ly6Chigh monocyte preponderance. Notably, Ly6Chigh skewing was preceded by monocyte metabolic reprogramming towards glycolysis, reduced oxidative potential and increased mitochondrial fission. In sum, short-term HFD changes BM cellularity, resulting in local adipocyte whitening driving a gradual increase and activation of invasive Ly6Chigh monocytes.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files.
Article and author information
Author details
Funding
Canadian Institutes of Health Research FDN-143203 (FDN-143203)
- Amira Klip
Canadian Institutes of Health Research FDN-14333 (FDN-14333)
- Dana J Philpott
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: Mouse protocols followed the strictest protocols dictated by the Canadian Institutes of Health Research guidelines and were approved by the animal care committee (Protocol #20011850 to S.E.G. and 483 D.J.P., University of Toronto; and #1000047074 to A.K., The Hospital for Sick Children).
Copyright
© 2022, Boroumand et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Bone marrow adipocytes drive the development of tissue invasive Ly6Chigh monocytes during obesity
eLife 11:e65553.
https://doi.org/10.7554/eLife.65553
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