Cell Reports
Volume 24, Issue 12, 18 September 2018, Pages 3180-3193
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Article
Adipose mTORC1 Suppresses Prostaglandin Signaling and Beige Adipogenesis via the CRTC2-COX-2 Pathway

https://doi.org/10.1016/j.celrep.2018.08.055Get rights and content
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Highlights

  • mTORC1 is a potent regulator of white to beige adipogenesis

  • mTORC1 inhibition leads to WAT browning and occurs despite sympathetic denervation

  • COX-2 and prostaglandins are essential for browning of WAT in Raptor-deficient mice

  • mTORC1 suppresses COX-2/PG pathway via a CRTC2-dependent mechanism

Summary

Beige adipocytes are present in white adipose tissue (WAT) and have thermogenic capacity to orchestrate substantial energy metabolism and counteract obesity. However, adipocyte-derived signals that act on progenitor cells to control beige adipogenesis remain poorly defined. Here, we show that adipose-specific depletion of Raptor, a key component of mTORC1, promoted beige adipogenesis through prostaglandins (PGs) synthesized by cyclooxygenase-2 (COX-2). Moreover, Raptor-deficient mice were resistant to diet-induced obesity and COX-2 downregulation. Mechanistically, mTORC1 suppressed COX-2 by phosphorylation of CREB-regulated transcription coactivator 2 (CRTC2) and subsequent dissociation of CREB to cox-2 promoter in adipocytes. PG treatment stimulated PKA and promoted differentiation of progenitor cells to beige adipocytes in culture. Ultimately, we show that pharmacological inhibition or suppression of COX-2 attenuated mTORC1 inhibition-induced thermogenic gene expression in inguinal WAT in vivo and in vitro. Our study identifies adipocyte-derived PGs as key regulators of white adipocyte browning, which occurs through mTORC1 and CRTC2.

Keywords

mTORC1
COX-2
CRTC2
UCP1
prostaglandin
beige adipocyte
adipose tissue
thermogenesis

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