Leptin receptor-positive and leptin receptor-negative proopiomelanocortin neurons innervate an identical set of brain structures

Autor(es)

Lima, Leandro B. ; Metzger, Martin ; Furigo, Isadora C. ; Donato, Jr., J.

• Tipo de documento: Artigo Científico
• Fonte: Brain Research; v. 1646, p. 366-376, SEP 1 2016.
• Citações Web of Science: 7

Resumo

Neurons that express the prohormone proopiomelanocortin (POMC) in the arcuate hypothalamic nucleus (Arc) are engaged in the regulation of energy balance and glucose homeostasis. Additionally, POMC neurons are considered key first-order cells regulated by leptin. Interestingly, in the Arc, POMC cells that express the leptin receptor (POMC/LepR+ cells) are found side by side with POMC cells not directly responsive to leptin (POMC/LepR- cells). However, it remains unknown whether these distinct populations innervate different target regions. Therefore, the objective of the present study was to compare the projections of POMC/LepR+ and POMC/LepR- neurons. Using genetically modified LepR-reporter mice to identify leptin receptor-expressing cells and immunohistochemistry to stain POMC-derived peptides (alpha-MSH or beta-endorphin) we confirmed that approximately 80% of Arc beta-endorphin-positive neurons co-expressed leptin receptors. POMC/LepR+ and POMC/LepR- axons were intermingled in all of their target regions. As revealed by confocal microscopy, we found an elevated degree of co-localization between alpha-MSH+ axons and the reporter protein (tdTomato) in all brain regions analyzed, with co-localization coefficients ranging from 0.889 to 0.701. Thus, these two populations of POMC neurons seem to project to the same set of brain structures, although one of the two subtypes of POMC axons was sometimes found to be more abundant than the other in distinct subregions of the same nucleus. Therefore, POMC/LepR+ and POMC/LepR- cells may target separate neuronal populations and consequently activate distinct neuronal circuits within some target nuclei. These findings contribute to unravel the neuronal circuits involved in the regulation of energy balance and glucose homeostasis. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 15/10992-6 - Estudo da programação metabólica por meio de diferentes abordagens
• Beneficiário: Jose Donato Junior
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 12/02388-3 - Topografia e assinatura neuroquímica das projeções entre a habenula lateral, o núcleo rostromedial tegmental e o núcleo dorsal da rafe no rato
• Beneficiário: Martin Andreas Metzger
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 10/18086-0 - Bases moleculares da resistência à leptina
• Beneficiário: Jose Donato Junior
• Linha de fomento: Auxílio à Pesquisa - Apoio a Jovens Pesquisadores