1
|
Nestor CC, Qiu J, Padilla SL, Zhang C, Bosch MA, Fan W, Aicher SA, Palmiter RD, Rønnekleiv OK, Kelly MJ. Optogenetic Stimulation of Arcuate Nucleus Kiss1 Neurons Reveals a Steroid-Dependent Glutamatergic Input to POMC and AgRP Neurons in Male Mice. Mol Endocrinol 2016; 30:630-44. [PMID: 27093227 DOI: 10.1210/me.2016-1026] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Kisspeptin (Kiss1) neurons are essential for reproduction, but their role in the control of energy balance and other homeostatic functions remains unclear. Proopiomelanocortin (POMC) and agouti-related peptide (AgRP) neurons, located in the arcuate nucleus (ARC) of the hypothalamus, integrate numerous excitatory and inhibitory inputs to ultimately regulate energy homeostasis. Given that POMC and AgRP neurons are contacted by Kiss1 neurons in the ARC (Kiss1(ARC)) and they express androgen receptors, Kiss1(ARC) neurons may mediate the orexigenic action of testosterone via POMC and/or AgRP neurons. Quantitative PCR analysis of pooled Kiss1(ARC) neurons revealed that mRNA levels for Kiss1 and vesicular glutamate transporter 2 were higher in castrated male mice compared with gonad-intact males. Single-cell RT-PCR analysis of yellow fluorescent protein (YFP) ARC neurons harvested from males injected with AAV1-EF1α-DIO-ChR2:YFP revealed that 100% and 88% expressed mRNAs for Kiss1 and vesicular glutamate transporter 2, respectively. Whole-cell, voltage-clamp recordings from nonfluorescent postsynaptic ARC neurons showed that low frequency photo-stimulation (0.5 Hz) of Kiss1-ChR2:YFP neurons elicited a fast glutamatergic inward current in POMC and AgRP neurons. Paired-pulse, photo-stimulation revealed paired-pulse depression, which is indicative of greater glutamate release, in the castrated male mice compared with gonad-intact male mice. Group I and group II metabotropic glutamate receptor agonists depolarized and hyperpolarized POMC and AgRP neurons, respectively, which was mimicked by high frequency photo-stimulation (20 Hz) of Kiss1(ARC) neurons. Therefore, POMC and AgRP neurons receive direct steroid- and frequency-dependent glutamatergic synaptic input from Kiss1(ARC) neurons in male mice, which may be a critical pathway for Kiss1 neurons to help coordinate energy homeostasis and reproduction.
Collapse
Affiliation(s)
- Casey C Nestor
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| | - Jian Qiu
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| | - Stephanie L Padilla
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| | - Chunguang Zhang
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| | - Martha A Bosch
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| | - Wei Fan
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| | - Sue A Aicher
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| | - Richard D Palmiter
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| | - Oline K Rønnekleiv
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| | - Martin J Kelly
- Department of Physiology and Pharmacology (C.CN., J.Q., C.Z., M.A.B., S.A.A., O.K.R., M.J.K.) and Anesthesiology and Perioperative Medicine and Knight Cardiovascular Institute (W.F.), Oregon Health & Science University, Portland, Oregon 97239; Division of Neuroscience (O.K.R., M.J.K.), Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006; and Howard Hughes Medical Institute (S.L.P., R.D.P.), University of Washington, Seattle, Washington 98195
| |
Collapse
|
2
|
Acosta-Martínez M. PI3K: An Attractive Candidate for the Central Integration of Metabolism and Reproduction. Front Endocrinol (Lausanne) 2011; 2:110. [PMID: 22654843 PMCID: PMC3356143 DOI: 10.3389/fendo.2011.00110] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 12/13/2011] [Indexed: 12/19/2022] Open
Abstract
In neurons, as in a variety of other cell types, the enzyme phosphatidylinositol-3-kinase (PI3K) is a key intermediate that is common to the signaling pathways of a number of peripheral metabolic cues, including insulin and leptin, which are well known to regulate both metabolic and reproductive functions. This review article will explore the possibility that PI3K is a key integrator of metabolic and neural signals regulating gonadotropin releasing hormone (GnRH)/luteinizing hormone (LH) release and explore the hypothesis that this enzyme is pivotal in many disorders where gonadotropin release is at risk. Although the mechanisms mediating the influence of metabolism and nutrition on fertility are currently unclear, the strong association between metabolic disorders and infertility is undeniable. For example, women suffering from anorectic disorders experience amenorrhea as a consequence of malnutrition-induced impairment of LH release, and at the other extreme, obesity is also commonly co-morbid with menstrual dysfunction and infertility. Impaired hypothalamic insulin and leptin receptor signaling is thought to be at the core of reproductive disorders associated with metabolic dysfunction. While low levels of leptin and insulin characterize states of negative energy balance, prolonged nutrient excess is associated with insulin and leptin resistance. Metabolic models known to alter GnRH/LH release such as diabetes, diet-induced obesity, and caloric restriction are also accompanied by impairment of PI3K signaling in insulin and leptin sensitive tissues including the hypothalamus. However, a clear link between this signaling pathway and the control of GnRH release by peripheral metabolic cues has not been established. Investigating the role of the signaling pathways shared by metabolic cues that are critical for a normal reproductive state can help identify possible targets in the treatment of metabolic and reproductive disorders such as polycystic ovarian syndrome.
Collapse
Affiliation(s)
- Maricedes Acosta-Martínez
- Department of Physiology and Biophysics, Medical Center, Stony Brook UniversityStony Brook, NY, USA
- *Correspondence: Maricedes Acosta-Martínez, Department of Physiology and Biophysics, Medical Center, Stony Brook University, Stony Brook, NY 11794-8661, USA. e-mail:
| |
Collapse
|