Abstract

Metabolic pathways and inflammatory processes are under circadian regulation. While rhythmic immune cell recruitment is known to impact infection outcomes, whether the circadian clock modulates immunometabolism remains unclear. We find the molecular clock Bmal1 is induced by inflammatory stimulants, including Ifn-g/lipopolysaccharide (M1) and tumor-conditioned medium, to maintain mitochondrial metabolism under these metabolically stressed conditions in mouse macrophages. Upon M1 stimulation, myeloid-specific Bmal1 knockout (M-BKO) renders macrophages unable to sustain mitochondrial function, enhancing succinate dehydrogenase (SDH)-mediated mitochondrial ROS production and Hif-1a-dependent metabolic reprogramming and inflammatory damage. In tumor-associated macrophages, the aberrant Hif-1a activation and metabolic dysregulation by M-BKO contribute to an immunosuppressive tumor microenvironment. Consequently, M-BKO increases melanoma tumor burden, while administrating an SDH inhibitor dimethyl malonate suppresses tumor growth. Therefore, Bmal1 functions as a metabolic checkpoint integrating macrophage mitochondrial metabolism, redox homeostasis and effector functions. This Bmal1-Hif-1a regulatory loop may provide therapeutic opportunities for inflammatory diseases and immunotherapy.

Data availability

Raw RNA-seq data submitted to GEO: accession number GSE148510. All analyzed RNA-seq and metabolite data are included in the manuscript and source data for Fig 3 and Fig. 5.

The following data sets were generated

Article and author information

Author details

  1. Ryan K Alexander

    Department of Molecular Metabolism, HSPH, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Yae-Huei Liou

    Department of Molecular Metabolism, HSPH, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Nelson H Knudsen

    Department of Molecular Metabolism, HSPH, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Kyle A Starost

    Department of Molecular Metabolism, HSPH, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Chuanrui Xu

    Department of Molecular Metabolism, HSPH, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3225-4083
  6. Alexander L Hyde

    Department of Molecular Metabolism, HSPH, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Sihao Liu

    Department of Molecular Metabolism, HSPH, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. David Jacobi

    Department of Molecular Metabolism, HSPH, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  9. Nan-Shih Liao

    Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
    Competing interests
    The authors declare that no competing interests exist.
  10. Chih-Hao Lee

    Department of Molecular Metabolism, HSPH, Boston, United States
    For correspondence
    clee@hsph.harvard.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6090-0786

Funding

National Institute of Allergy and Infectious Diseases (R21AI131659)

  • Chih-Hao Lee

National Institute of General Medical Sciences (F31GM117854)

  • Ryan K Alexander

National Institute of Diabetes and Digestive and Kidney Diseases (F31DK107256)

  • Nelson H Knudsen

Ministry of Science and Technology, Taiwan, ROC

  • Yae-Huei Liou

Academia Sinica (AS-106-TP-L08)

  • Nan-Shih Liao

American Heart Association (16GRNT31460005)

  • Chih-Hao Lee

National Institute of Diabetes and Digestive and Kidney Diseases (R01DK113791)

  • Chih-Hao Lee

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Animal experimentation: All animal studies were approved by the Harvard Medical Area Standing Committee on Animal Research. IACUC protocol #IS00001011

Copyright

© 2020, Alexander 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.

Metrics

  • 5,823
    views
  • 1,106
    downloads
  • 102
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Ryan K Alexander
  2. Yae-Huei Liou
  3. Nelson H Knudsen
  4. Kyle A Starost
  5. Chuanrui Xu
  6. Alexander L Hyde
  7. Sihao Liu
  8. David Jacobi
  9. Nan-Shih Liao
  10. Chih-Hao Lee
(2020)
Bmal1 integrates mitochondrial metabolism and macrophage activation
eLife 9:e54090.
https://doi.org/10.7554/eLife.54090

Share this article

https://doi.org/10.7554/eLife.54090

Further reading

    1. Cell Biology
    Swastika Sur, Maggie Kerwin ... Minnie M Sarwal
    Research Article

    Understanding the unique susceptibility of the human kidney to pH dysfunction and injury in cystinosis is paramount to developing new therapies to preserve renal function. Renal proximal tubular epithelial cells (RPTECs) and fibroblasts isolated from patients with cystinosis were transcriptionally profiled. Lysosomal fractionation, immunoblotting, confocal microscopy, intracellular pH, TEM, and mitochondrial stress test were performed for validation. CRISPR, CTNS -/- RPTECs were generated. Alterations in cell stress, pH, autophagic turnover, and mitochondrial energetics highlighted key changes in the V-ATPases in patient-derived and CTNS-/- RPTECs. ATP6V0A1 was significantly downregulated in cystinosis and highly co-regulated with loss of CTNS. Correction of ATP6V0A1 rescued cell stress and mitochondrial function. Treatment of CTNS -/- RPTECs with antioxidants ATX induced ATP6V0A1 expression and improved autophagosome turnover and mitochondrial integrity. Our exploratory transcriptional and in vitro cellular and functional studies confirm that loss of Cystinosin in RPTECs, results in a reduction in ATP6V0A1 expression, with changes in intracellular pH, mitochondrial integrity, mitochondrial function, and autophagosome-lysosome clearance. The novel findings are ATP6V0A1’s role in cystinosis-associated renal pathology and among other antioxidants, ATX specifically upregulated ATP6V0A1, improved autophagosome turnover or reduced autophagy and mitochondrial integrity. This is a pilot study highlighting a novel mechanism of tubular injury in cystinosis.

    1. Cell Biology
    2. Developmental Biology
    Yan Zhang, Hua Zhang
    Insight

    Long thought to have little relevance to ovarian physiology, the rete ovarii may have a role in follicular dynamics and reproductive health.