Aminoprocalcitonin-mediated suppression of feeding involves the hypothalamic melanocortin system

Abstract

Tavares E, Maldonado R, Miñano FJ. Aminoprocalcitonin-mediated suppression of feeding involves the hypothalamic melanocortin system. Am J Physiol Endocrinol Metab 304: E1251-E1262, 2013. First published April 9, 2013; doi:10.1152/ajpendo.00590.2012, a neuroendocrine peptide encoded by the calcitonin-I (CALC-I) gene, suppresses food intake when administered centrally in rats. However, the neural pathways underlying this effect remain unclear. N-PCT and calcitonin receptors (CT-R) have been identified in hypothalamic regions involved in energy homeostasis, including the arcuate nucleus (ARC). Here, we hypothesized an involvement of the hypothalamic ARC in mediating the anorexic effects of central N-PCT based on its content of peptidergic neurons involved in feeding and its expression of N-PCT and CT-R. Fasting strongly reduced expression of the N-PCT precursor gene CALC-I in the ARC, and central immunoneutralization of endogenous N-PCT increased food intake. Intracerebroventricular administration of N-PCT reduced food intake in fed and fasted rats, and its effect was attenuated by a neutralizing anti-N-PCT antibody. Immunohistochemistry for N-PCT showed that it is expressed in astrocytes and neurons in the ARC and is colocalized with anorexigenic proopiomelanocortin (POMC) neurons. Fasting reduced coexpression of N-PCT and POMC, and N-PCT administration activated hypothalamic neurons, including rostral POMC neurons. We also found that N-PCT stimulates POMC mRNA expression in fed and fasted rats, whereas it reduced the expression of orexigenic peptides neuropeptide Y (NPY) and agouti-related peptide (AgRP) only in fasted rats in which those mRNAs are normally elevated. Finally, we showed that the melanocortin-3/4 receptor antagonist SHU 9119 attenuates the intake-suppressive effect of N-PCT. These data demonstrate that hypothalamic N-PCT is involved in control of energy balance and that its anorexigenic effects are mediated through the melanocortin system. food intake; aminoprocalcitonin; arcuate nucleus; melanocortin system; proopiomelanocortin; neuropeptide Y AMINOPROCALCITONIN (N-PCT) was originally described as a 57-amino acid neuroendocrine peptide derived from the aminoterminal half of rat prohormone procalcitonin with bone cell mitogenic properties (6, 7). N-PCT derives from the calcitonin-I gene (CALC-I), which is localized in chromosome 11 (21, 50), a chromosome associated with body metabolism and obesity in humans (8). N-PCT, a highly conserved amino acid peptide with Ͼ85% amino acid identity in human and rodents (41), belongs to the calcitonin (CT) peptide family, which is made up by CT, CT gene-related peptide (CGRP), amylin, adrenomedullin, intermedin, and CT receptor-stimulating protein (3). These peptides function as ligands for a complex family of G protein-coupled receptors consisting of the CT receptor (CT-R), CT receptor-like receptor, and three receptorassociated modified proteins (40). CALC-I gene products and their receptors are widely distributed in the central nervous system (CNS), and sever...

Immunoneutralization of Endogenous Aminoprocalcitonin Attenuates Sepsis-Induced Acute Lung Injury and Mortality in Rats

“…The ability of this antibody to block the in vivo activity of endogenous NPCT in rats and its specificity on rat brain sections by preabsorption with the peptide have been previously reported. 20,35 Control rabbit nonimmune IgG was used as control (Sigma-Aldrich). Anti-NPCT and control IgG were dissolved in phosphatebuffered saline (PBS; pH 7.4) to a final concentration of 2.0 mg/mL.…”

“…Real-time PCR was performed as described previously. 13,20 Briefly, total RNA was extracted from lung homogenates using Tripure reagent (Roche Diagnostics) and then reverse transcribed into cDNA using the Quantitect Enzyme Reverse Transcriptase Kit (Qiagen, Hilden, Germany), according to the manufacturer's instructions. SYBR Green real-time RT-PCR was performed with the Stratagene Mx3005P sequence detection system (Agilent Technologies, Madrid, Spain) using SensiMix SYBR Low-ROX (Bioline GmbH, Luckenwalde, Germany).…”

“…32,33 It was also observed that central administration of NPCT simulates the inflammatory responses that occur in sepsis (fever, anorexia, and weight reduction) via activation of hypothalamic prostaglandin-dependent pathways, 34 and corticotrophin and melanocortin neurons, where CALCR/ CALCRL are abundantly expressed. 20,35 Recent studies suggest that NPCT is actively involved as a mediator of disease progression and severity in sepsis.…”

Hypothalamic effects of neonatal diet: reversible and only partially leptin dependent

“…In addition, western blot analysis in mouse pituitary has been performed by Berman and colleagues (Berman et al 2001), showing a predominant and predicted band at 23 kDa. This antibody has also been used by several other researchers for immunohistochemical localisation of POMC in feeding, stress or nociception-related studies (for example: Gotoh et al 2006, Reyes et al 2006, Evans et al 2007, DeBoer et al 2009, Cheng et al 2011, Singru et al 2012, Tavares et al 2013, Zhan et al 2013, Pandit et al 2016.…”

The role of leptin in central nervous system diseases

“…The ObRb is present in several neural tissues, but is mainly expressed in multiple hypothalamic regions including the arcuate nucleus (ARC), the ventromedial hypothalamus, the paraventricular nucleus, the dorsomedial hypothalamus, the lateral hypothalamic area, and the ventral premammillary nucleus 33 , 34 . Leptin’s action on two distinct populations of ARC neurons is well described, one of which is the orexigenic neuropeptides neuropeptide Y (NPY) and agouti-related peptide (AgRP) 35 , whereas the other is anorexigenic neuropeptides cocaine and amphetamine-related transcript and pro-opiomelanocortin 36 , 37 . In contrast to ObRb, the short-form leptin receptor ObRa have short C-terminal domains and are considered to be mainly involved in endocytosis and transport of leptin across the blood–brain barrier 38 .…”