Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Aug 11;5(10):844-857.
doi: 10.1016/j.molmet.2016.08.003. eCollection 2016 Oct.

Defining a novel leptin-melanocortin-kisspeptin pathway involved in the metabolic control of puberty

Maria Manfredi-Lozano  1 , Juan Roa  2 , Francisco Ruiz-Pino  3 , Richard Piet  4 , David Garcia-Galiano  5 , Rafael Pineda  6 , Aurora Zamora  5 , Silvia Leon  5 , Miguel A Sanchez-Garrido  7 , Antonio Romero-Ruiz  5 , Carlos Dieguez  8 , Maria Jesus Vazquez  3 , Allan E Herbison  4 , Leonor Pinilla  3 , Manuel Tena-Sempere  9
Affiliations

Defining a novel leptin-melanocortin-kisspeptin pathway involved in the metabolic control of puberty

Maria Manfredi-Lozano et al. Mol Metab. .

Abstract

Objective: Puberty is a key developmental phenomenon highly sensitive to metabolic modulation. Worrying trends of changes in the timing of puberty have been reported in humans. These might be linked to the escalating prevalence of childhood obesity and could have deleterious impacts on later (cardio-metabolic) health, but their underlying mechanisms remain unsolved. The neuropeptide α-MSH, made by POMC neurons, plays a key role in energy homeostasis by mediating the actions of leptin and likely participates in the control of reproduction. However, its role in the metabolic regulation of puberty and interplay with kisspeptin, an essential puberty-regulating neuropeptide encoded by Kiss1, remain largely unknown. We aim here to unveil the potential contribution of central α-MSH signaling in the metabolic control of puberty by addressing its role in mediating the pubertal effects of leptin and its potential interaction with kisspeptin.

Methods: Using wild type and genetically modified rodent models, we implemented pharmacological studies, expression analyses, electrophysiological recordings, and virogenetic approaches involving DREADD technology to selectively inhibit Kiss1 neurons, in order to interrogate the physiological role of a putative leptin→α-MSH→kisspeptin pathway in the metabolic control of puberty.

Results: Stimulation of central α-MSH signaling robustly activated the reproductive axis in pubertal rats, whereas chronic inhibition of melanocortin receptors MC3/4R, delayed puberty, and prevented the permissive effect of leptin on puberty onset. Central blockade of MC3/4R or genetic elimination of kisspeptin receptors from POMC neurons did not affect kisspeptin effects. Conversely, congenital ablation of kisspeptin receptors or inducible, DREADD-mediated inhibition of arcuate nucleus (ARC) Kiss1 neurons resulted in markedly attenuated gonadotropic responses to MC3/4R activation. Furthermore, close appositions were observed between POMC fibers and ARC Kiss1 neurons while blockade of α-MSH signaling suppressed Kiss1 expression in the ARC of pubertal rats.

Conclusions: Our physiological, virogenetic, and functional genomic studies document a novel α-MSH→kisspeptin→GnRH neuronal signaling pathway involved in transmitting the permissive effects of leptin on pubertal maturation, which is relevant for the metabolic (and, eventually, pharmacological) regulation of puberty onset.

Keywords: DREADDs; Kisspeptin; Leptin; Metabolism; Puberty; α-MSH.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Central activation of α-MSH signaling, preferentially via MC4R, stimulates LH secretion in pubertal but not infantile rats. (A) The effects of intracerebroventricular (icv) injection of an effective dose (1 nmol) of the MC3/4R agonist MT-II on LH secretion in infantile (PND-15) male and female rats (n = 10/group) are shown. In addition, LH responses to MT-II injection (icv, 1 nmol) in pubertal male (Panel B; n = 12) and female (C; n = 10) rats are presented. (D, E) the effects on LH secretion of the icv injection of a range of doses of selective MC3R (upper) or MC4R (lower) agonists in pubertal male rats (n = 10/group) are depicted. In addition to time-course responses, integral LH responses, calculated as AUC over the 60-min period after injection, are shown in the insets. * P < 0.05, ** P < 0.01 and *** P < 0.001 vs. corresponding time-points in vehicle-injected animals (ANOVA followed by Student–Newman–Keuls multiple range test).
Figure 2
Figure 2
Central blockade of α-MSH signaling inhibits puberty onset and prevents the permissive effects of leptin. (A) The effects of repeated intracerebroventricular (icv) injection of the MC3/4R antagonist SHU9119 or vehicle on pubertal progression in immature female rats (n = 10/group) are shown. Female rats were icv injected with 1 nmol SHU9119 every 12-h between PND-29 to PND-35. Evolution of vaginal opening (VO), as external signal of puberty, together with body weight and leptin levels, as well as uterus (UW) and ovarian (OW) weights and LH concentrations, in terminal (PND-35) samples are shown. (B) The effects of icv administration of repeated doses of leptin, alone or in combination with the MC3/4R antagonist SHU9119 in a rat model of moderate under-nutrition (UN) are displayed (n = 10–14/group). In detail, BW, UW, and VO data from pubertal UN rats treated with vehicle, leptin, or leptin + SHU9119 are shown. Data from age-matched female rats fed ad libitum (normal nutrition: NN) and injected with vehicle are shown for reference purposes (n = 9). For (A) * P < 0.05 vs. corresponding time-points in vehicle-injected animals (Student t-test); for (B) groups with different superscript letters are statistically different (P < 0.05; ANOVA followed by Student–Newman–Keuls multiple range test).
Figure 3
Figure 3
α-MSH signaling does not mediate the stimulatory effects of kisspeptin on puberty/gonadotropic axis. (A) The effects of intracerebroventricular (icv) injection of an effective dose (1 nmol) of the MC3/4R antagonist SHU9119 on basal LH secretion and stimulated responses to MT-II and Kp-10 are presented (n = 9–10/group). While SHU9119 decreased basal LH levels and fully prevented LH responses to the MC3/4R agonist MT-II in pubertal male rats, it did not affect LH responses to a submaximal (50 pmol) dose of Kp-10. (B) A summary of phenotypic and hormonal indices from a mouse model of congenital elimination of kisspeptin receptor Gpr54 from POMC neurons is shown. Neither VO (as external sign of puberty) nor the age of first estrus or the magnitude of LH responses to Kp-10 were altered in mice with congenital ablation of Gpr54 in POMC neurons. Note that basal LH levels were not altered and are denoted as dotted line (right panel). *** P < 0.001 vs. corresponding time-points in vehicle-injected animals (Student t-test or ANOVA followed by Student–Newman–Keuls multiple range test).
Figure 4
Figure 4
Interplay between POMC/Kiss1 neurons and Kiss1 expression after blockade of α-MSH signaling. (A) Three representative examples are shown of immunohistochemical analyses in different sections of the putative interactions between MSH-positive fibers (in magenta) and kisspeptin (Kp)-positive cell bodies (in green) in the ARC of pubertal female rats. Reconstruction 3-D analysis of the particular example of Neuron-3 is shown at the bottom of panel A. (B) The effects of repeated intracerebroventricular (icv) injection of the MC3/4R antagonist SHU9119 on Kiss1 mRNA expression in the ARC and RP3V of pubertal female rats are presented. Female rats (n = 5) were icv injected with 1 nmol SHU9119 every 12-h between PND-28 to PND-32. Kiss1 expression was assessed by ISH; besides representative photomicrographs, quantitative data are presented in the lower panels. *P < 0.05 vs. corresponding values for each hypothalamic area in vehicle-injected animals (P < 0.05; Student t-test).
Figure 5
Figure 5
Kisspeptin signaling is a major mediator for the stimulatory effects of α-MSH on LH secretion. (A) The effects of intracerebroventricular (icv) injection of an effective dose (1 nmol) of the MC3/4R agonist MT-II on LH secretion in WT mice and mice with congenital inactivation of the kisspeptin receptor Gpr54 are shown (n = 7–12/group). LH responses are presented from WT and KO animals, at 15-min after icv injection of MT-II. (B) The effects on LH secretion of the icv injection of MT-II (1-nmol) in mice with DREADD-mediated inhibition of Kiss1 neurons are shown. The first two bars correspond to control animals, infected with mock viral constructs; the following two bars correspond to mice effectively infected with hM4-constructs in the ARC, following receptor activation by CNO administration (n = 7/group). Responses in mice injected with vehicle or MT-II are shown. In addition, in the inset, the magnitude of LH responses to MT-II in animals without effective infection with hM4 in the ARC (in the presence and absence of CNO) is displayed (n = 7/group). In the lower panels, representative photomicrographs of mCherry immunohistochemistry in mice with effective (AAV-hM4D ARC+) or ineffective (AAV-hM4D ARC-) targeting of the ARC nucleus are presented. In panel A, *P < 0.05 vs. corresponding time-points in vehicle-injected animals; aP < 0.05 vs. corresponding WT values. Groups with different superscript letters are statistically different (ANOVA followed by Student–Newman–Keuls multiple range test).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Parent A.S., Teilmann G., Juul A., Skakkebaek N.E., Toppari J., Bourguignon J.P. The timing of normal puberty and the age limits of sexual precocity: variations around the world, secular trends, and changes after migration. Endocrine Reviews. 2003;24:668–693. - PubMed
    1. Aksglaede L., Juul A., Olsen L.W., Sorensen T.I. Age at puberty and the emerging obesity epidemic. PLoS One. 2009;4:e8450. - PMC - PubMed
    1. De Leonibus C., Marcovecchio M.L., Chiavaroli V., de Giorgis T., Chiarelli F., Mohn A. Timing of puberty and physical growth in obese children: a longitudinal study in boys and girls. Pediatric Obesity. 2013;9:292–299. - PubMed
    1. Day F.R., Elks C.E., Murray A., Ong K.K., Perry J.R. Puberty timing associated with diabetes, cardiovascular disease and also diverse health outcomes in men and women: the UK Biobank study. Scientific Reports. 2015;5:11208. - PMC - PubMed
    1. Lakshman R., Forouhi N.G., Sharp S.J., Luben R., Bingham S.A., Khaw K.T. Early age at menarche associated with cardiovascular disease and mortality. The Journal of Clinical Endocrinology and Metabolism. 2009;94:4953–4960. - PubMed