Central lipid sensing pathways contribute to the control of puberty and its alterations in conditions of obesity

Childhood obesity, especially in girls, often correlates with advanced puberty and long-term comorbidities. Among the central circuits controlling energy homeostasis, hypothalamic lipid sensing pathways, involving free fatty-acid receptors (FFARs), peroxisome proliferator-activated receptors (PPARs), and the bile-acid (BA) receptor, Takeda G protein-coupled receptor 5 (TGR5), have been recognized as major players, with putative pathogenic roles in obesity and its complications. However, their contribution to pubertal regulation and obesity-induced pubertal alterations remains largely unexplored. We describe herein changes in the hypothalamic profiles of specific lipid species, including certain fatty-acyls, BA derivatives, and several glycerolphospholipids, during the juvenile-pubertal transition and conditions of overweight linked to precocious puberty in female rats. Hypothalamic expression of the FFAR, GPR84, as well as Ppar-γ and Tgr5 gradually increased during the infantile-prepubertal transition, whereas early overfeeding increased hypothalamic mRNA levels of the FFARs, Gpr43, and GPR84. Expression of GPR84, Ppar-α, and Tgr5 was documented in FACS-isolated Kiss1 neurons from juvenile and pubertal female mice. Central pharmacological gain- and loss-of-function manipulations of GPR84-, PPAR-, or TGR5-signaling in prepubertal lean and early overfed female rats resulted in specific changes in pubertal timing. In lean rats, central blockade of PPAR-γ/α delayed puberty onset, whereas in early overfed rats, central stimulation of TGR5 signaling partially prevented obesity-induced advanced puberty; effects that were also marginally observed after GPR84 inhibition. Our results disclose the role of brain lipid-sensing pathways in the control of puberty, with a variable contribution of central FFAR-, PPAR-, and TGR5-signaling depending on the maturational and nutritional status.NEW & NOTEWORTHY Puberty is highly sensitive to body energy status, and child obesity is often linked to perturbed puberty. However, whether this comes from excessive energy stores or specific nutrient signals altered in obesity remains largely unexplored. Using suitable preclinical models of early obesity and accelerated puberty, we disclose herein conclusive evidence for altered hypothalamic lipid profiles and the roles of specific lipid-sensing pathways in pubertal control, with a variable contribution depending on the maturational and nutritional status.

Kiss1; fatty acid receptors; lipid sensing; obesity; puberty.