1. Academic Validation
  2. Central CCL2 signaling onto MCH neurons mediates metabolic and behavioral adaptation to inflammation

Central CCL2 signaling onto MCH neurons mediates metabolic and behavioral adaptation to inflammation

  • EMBO Rep. 2016 Dec;17(12):1738-1752. doi: 10.15252/embr.201541499.
Ophélia Le Thuc 1 2 Céline Cansell 1 2 Miled Bourourou 1 2 Raphaël Gp Denis 3 Katharina Stobbe 1 2 Nadège Devaux 1 2 Alice Guyon 1 2 Julie Cazareth 1 2 Catherine Heurteaux 1 2 William Rostène 4 Serge Luquet 3 Nicolas Blondeau 1 2 Jean-Louis Nahon 5 2 6 Carole Rovère 5 2
Affiliations

Affiliations

  • 1 Université Côte d'Azur, Nice, France.
  • 2 CNRS, IPMC, Sophia Antipolis, France.
  • 3 Univ Paris Diderot Sorbonne Paris Cité Unité de Biologie Fonctionnelle et Adaptative CNRS UMR 8251, Paris, France.
  • 4 Institut de la Vision UMRS 968-Université Pierre et Marie Curie, Paris, France.
  • 5 Université Côte d'Azur, Nice, France rovere@ipmc.cnrs.fr nahonjl@ipmc.cnrs.fr.
  • 6 Station de Primatologie UPS846 CNRS, Rousset-sur-Arc, France.
Abstract

Sickness behavior defines the endocrine, autonomic, behavioral, and metabolic responses associated with Infection. While inflammatory responses were suggested to be instrumental in the loss of appetite and body weight, the molecular underpinning remains unknown. Here, we show that systemic or central lipopolysaccharide (LPS) injection results in specific hypothalamic changes characterized by a precocious increase in the chemokine ligand 2 (CCL2) followed by an increase in pro-inflammatory cytokines and a decrease in the orexigenic neuropeptide melanin-concentrating hormone (MCH). We therefore hypothesized that CCL2 could be the central relay for the loss in body weight induced by the inflammatory signal LPS. We find that central delivery of CCL2 promotes neuroinflammation and the decrease in MCH and body weight. MCH neurons express CCL2 receptor and respond to CCL2 by decreasing both electrical activity and MCH release. Pharmacological or genetic inhibition of CCL2 signaling opposes the response to LPS at both molecular and physiologic levels. We conclude that CCL2 signaling onto MCH neurons represents a core mechanism that relays peripheral inflammation to sickness behavior.

Keywords

CCL2 chemokine; CCR2 signaling pathway; melanin‐concentrating hormone; neuroinflammation; weight loss.

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