Cell Reports (Apr 2024)

MAFB in macrophages regulates cold-induced neuronal density in brown adipose tissue

  • Manoj Kumar Yadav,
  • Megumi Ishida,
  • Natalia Gogoleva,
  • Ching-Wei Liao,
  • Filiani Natalia Salim,
  • Maho Kanai,
  • Akihiro Kuno,
  • Takuto Hayashi,
  • Zeynab Javanfekr Shahri,
  • Kaushalya Kulathunga,
  • Omar Samir,
  • Wenxin Lyu,
  • Olivia Olivia,
  • Evaristus C. Mbanefo,
  • Satoru Takahashi,
  • Michito Hamada

Journal volume & issue
Vol. 43, no. 4
p. 113978

Abstract

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Summary: Transcription factor MAFB regulates various homeostatic functions of macrophages. This study explores the role of MAFB in brown adipose tissue (BAT) thermogenesis using macrophage-specific Mafb-deficient (Mafbf/f::LysM-Cre) mice. We find that Mafb deficiency in macrophages reduces thermogenesis, energy expenditure, and sympathetic neuron (SN) density in BAT under cold conditions. This phenotype features a proinflammatory environment that is characterized by macrophage/granulocyte accumulation, increases in interleukin-6 (IL-6) production, and IL-6 trans-signaling, which lead to decreases in nerve growth factor (NGF) expression and reduction in SN density in BAT. We confirm MAFB regulation of IL-6 expression using luciferase readout driven by IL-6 promoter in RAW-264.7 macrophage cell lines. Immunohistochemistry shows clustered organization of NGF-producing cells in BAT, which are primarily TRPV1+ vascular smooth muscle cells, as additionally shown using single-cell RNA sequencing and RT-qPCR of the stromal vascular fraction. Treating Mafbf/f::LysM-Cre mice with anti-IL-6 receptor antibody rescues SN density, body temperature, and energy expenditure.

Keywords