AUTHOR=Camerino Claudia , Conte Elena , Cannone Maria , Caloiero Roberta , Fonzino Adriano , Tricarico Domenico 

TITLE=Nerve Growth Factor, Brain-Derived Neurotrophic Factor and Osteocalcin Gene Relationship in Energy Regulation, Bone Homeostasis and Reproductive Organs Analyzed by mRNA Quantitative Evaluation and Linear Correlation Analysis

JOURNAL=Frontiers in Physiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2016.00456

DOI=10.3389/fphys.2016.00456

ISSN=1664-042X

ABSTRACT=<p>Nerve Growth Factor (NGF)/Brain-derived Neurotrophic Factor (BDNF) and osteocalcin share common effects regulating energy, bone mass, reproduction and neuronal functions. To investigate on the gene-relationship between NGF, BDNF, and Osteocalcin we compared by RT-PCR the transcript levels of <italic>Ngf, Bdnf</italic> and <italic>Osteocalcin</italic> as well as of their receptors <italic>p75NTR/NTRK1, NTRK2</italic>, and <italic>Gprc6a</italic> in brain, bone, white/brown adipose tissue (WAT/BAT) and reproductive organs of 3 months old female and male mice. Brain and bone were used as positive controls for NGF/BDNF and Osteocalcin respectively. The role of oxitocin(<italic>Oxt</italic>) and its receptor(<italic>Oxtr</italic>) was also investigated. <italic>Ngf</italic> expression shows an opposite trend compared to <italic>Bdnf</italic>. <italic>Ngf</italic> /<italic>p75NTR</italic> expression is 50% higher in BAT than brain, in both genders, but lower in bone. In contrast, <italic>Bdnf</italic> expression in bone is higher than in brain, but low in BAT/WAT. We found <italic>Osteocalcin</italic> gene expressed in brain in both genders, but <italic>Gprc6a</italic> expression is low in brain and BAT/WAT. As expected, <italic>Gprc6a</italic> gene is expressed in bone. <italic>Oxt</italic> gene was markedly expressed in brain, <italic>Oxtr</italic> in the ovaries and in fat and bone in both genders. <italic>Ngf</italic> is highly expressed in reproductive tissues and <italic>p75NTR</italic> mRNA levels are respectively 300, 100, and 50% higher in testis/ovaries/uterus than in brain. In contrast, BDNF genes are not expressed in reproductive tissues. As expected, <italic>Gprc6a</italic> is expressed in testis but not in the ovaries/uterus. A significant correlation was found between the expression levels of the gene ligands and their receptors in brain, BAT and testis suggesting a common pathway of different genes in these tissues in either male and female. Changes in the expression levels of <italic>osteocalcin, Ngf</italic>, or <italic>Bdnf</italic> genes may mutually affect the expression levels of the others. Moreover, it may be possible that different ligands may operate through different receptor subtypes. <italic>Oxt</italic> and <italic>Oxtr</italic> failed to show significant correlation. The up-regulation of <italic>Ngf</italic> /<italic>p75NTR</italic> in BAT is consistent with NGF as an energy regulator and with BDNF regulating bone.</p>