Genetic Targeting of Green Fluorescent Protein to Gonadotropin-Releasing Hormone Neurons: Characterization of Whole-Cell Electrophysiological Properties and Morphology1

Suter, Kelly J.; Song, Walter J.; Sampson, Traci L.; Wuarin, Jean Pierre; Saunders, Justin T.; Dudek, F. Edward; Moenter, Suzanne M.

doi:10.1210/endo.141.1.7279

Cited by 198 publications

(22 citation statements)

References 40 publications

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“…At least 10 animals/diet or treatment were analyzed unless otherwise indicated, and differences from corresponding controls were compared by Student’s t test. GnRH-GFP mice were kindly provided by Dr. Suzanne Moenter [64] to facilitate investigation of fluorescently labeled GnRH neurons.…”

Section: Methodsmentioning

confidence: 99%

Leukemia Inhibitory Factor Represses GnRH Gene Expression via cFOS during Inflammation in Male Mice

Lainez

Coss²

2019

Neuroendocrinology

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Background: The mechanisms whereby neuroinflammation negatively affects neuronal function in the hypothalamus are not clear. Our previous study determined that obesity-mediated chronic inflammation elicits sex-specific impairment in reproductive function via reduction in spine density in gonadotropin-releasing hormone (GnRH) neurons. Neuroinflammation and subsequent decrease in GnRH neuron spine density was specific for male mice, while protection in females was independent of ovarian estrogens. Methods: To examine if neuroinflammation-induced cytokines can directly regulate GnRH gene expression, herein we examined signaling pathways and mechanisms in males in vivo and in GnRH-expressing cell line, GT1–7. Results: GnRH neurons express cytokine receptors, and chronic or acute neuroinflammation represses GnRH gene expression in vivo. Leukemia inhibitory factor (LIF) in particular represses GnRH expression in GT1–7 cells, while other cytokines do not. STAT3 and MAPK pathways are activated following LIF treatment, but only MAPK pathway, specifically p38α, is sufficient to repress the GnRH gene. LIF induces cFOS that represses the GnRH gene via the -1,793 site in the enhancer region. In vivo, following high-fat diet, cFOS is induced in GnRH neurons and neurons juxtaposed to the leaky blood brain barrier of the organum vasculosum of the lamina terminalis, but not in the neurons further away. Conclusion: Our results indicate that the increase in LIF due to neuroinflammation induces cFOS and represses the GnRH gene. Therefore, in addition to synaptic changes in GnRH neurons, neuroinflammatory cytokines directly regulate gene expression and reproductive function, and the specificity for neuronal targets may stem from the proximity to the fenestrated capillaries.

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Section: Methodsmentioning

confidence: 99%

Leukemia Inhibitory Factor Represses GnRH Gene Expression via cFOS during Inflammation in Male Mice

Lainez

Coss²

2019

Neuroendocrinology

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“…Adult (2-3 months old) transgenic female mice in which GFP is genetically targeted to GnRH neurons (22) were used. Mice were housed on a 14-h light:10-h dark cycle with lights off at 6:30 p.m. (all times are Eastern standard time) and maintained on Harlan 2916 chow and water ad libitum.…”

Section: Methodsmentioning

confidence: 99%

“…The use of mice in studies investigating the GnRH system has increased greatly in recent years (19)(20)(21)(22)(23)(24)(25)(26). Previous studies in mice have used a regimen of ovariectomy followed by injections of estrogen and͞or progesterone at specific times to induce a LH surge (12,27).…”

mentioning

confidence: 99%

“…Here, we created a mouse model exhibiting daily LH surges with OVXϩE treatment using transgenic mice in which GnRH neurons are identifiable by GFP expression (22), allowing for direct electrophysiological examination of the surge mechanism. To test the hypothesis that the GnRH surge is generated by an increase in GnRH neuron activity, we made noninvasive singleunit extracellular recordings of GnRH neurons (30) to examine changes in individual GnRH neuron firing rates and patterns associated with both the LH surge and the switch from estradiol negative to positive feedback.…”

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confidence: 99%

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Diurnal and estradiol-dependent changes in gonadotropin-releasing hormone neuron firing activity

Christian

Mobley

Moenter

2005

Proc. Natl. Acad. Sci. U.S.A.

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192

213

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A robust gonadotropin-releasing hormone (GnRH) surge is a prerequisite signal for the luteinizing hormone (LH) surge that triggers ovulation. In rodents, the GnRH surge is initiated by elevated estradiol and a diurnal switch in estrogen action from negative to positive feedback. The ability of constant estradiol treatment to induce daily LH surges was tested in adult mice that were ovariectomized (OVX) or OVX and treated with estradiol implants (OVX؉E). LH in OVX mice showed no time-of-day difference. In contrast, OVX؉E mice showed a large LH surge (8-to 124-fold relative to the a.m.) in p.m. samples on d 2-5 post-OVX؉E. Targeted extracellular recordings were used to examine changes in firing activity of GnRH neurons in brain slices. There was no time-of-day difference in cells from OVX mice. In contrast, OVX؉E cells recorded in the p.m. showed an increased mean firing rate and instantaneous firing frequency, which could increase GnRH release, and decreased duration of quiescence between bouts of firing, possibly reflecting increased pulse frequency, compared with cells recorded in the a.m. In the a.m., OVX؉E cells showed changes in GnRH neuron firing reflecting negative feedback compared with OVX cells, whereas in the p.m., OVX؉E cells exhibited changes suggesting positive feedback. These data indicate that differences in pattern and level of individual GnRH neuron firing may reflect the switch in estradiol action and underlie GnRH surge generation. The persistence of altered GnRH neuron activity in slices indicates that this approach can be used to study the neurobiological mechanisms of surge generation.luteinizing hormone ͉ mouse model ͉ surge ͉ electrophysiology ͉ neuroendocrinology

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“…They were housed in light (12:12 light-dark cycle, lights on at 06:00 h) – and temperature (22 ± 2°C) controlled environment, with free access to standard food and tap water. GnRH-green-fluorescent protein (GnRH-GFP) transgenic mice (Suter et al, 2000) bred on a C57BL/6J genetic background were used. In this animal model, a GnRH promoter segment drives selective GFP expression in the majority of GnRH neurons.…”

Section: Methodsmentioning

confidence: 99%

Proestrus Differentially Regulates Expression of Ion Channel and Calcium Homeostasis Genes in GnRH Neurons of Mice

Vastagh

Solymosi

Farkas

et al. 2019

Front. Mol. Neurosci.

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In proestrus, the changing gonadal hormone milieu alters the physiological properties of GnRH neurons and contributes to the development of the GnRH surge. We hypothesized that proestrus also influences the expression of different ion channel genes in mouse GnRH neurons. Therefore, we performed gene expression profiling of GnRH neurons collected from intact, proestrous and metestrous GnRH-GFP transgenic mice, respectively. Proestrus changed the expression of 37 ion channel and 8 calcium homeostasis-regulating genes. Voltage-gated sodium channels responded with upregulation of three alpha subunits ( Scn2a1 , Scn3a , and Scn9a ). Within the voltage-gated potassium channel class, Kcna1 , Kcnd3 , Kcnh3 , and Kcnq2 were upregulated, while others ( Kcna4 , Kcnc3 , Kcnd2 , and Kcng1 ) underwent downregulation. Proestrus also had impact on inwardly rectifying potassium channel subunits manifested in enhanced expression of Kcnj9 and Kcnj10 genes, whereas Kcnj1 , Kcnj11 , and Kcnj12 subunit genes were downregulated. The two-pore domain potassium channels also showed differential expression with upregulation of Kcnk1 and reduced expression of three subunit genes ( Kcnk7 , Kcnk12 , and Kcnk16 ). Changes in expression of chloride channels involved both the voltage-gated ( Clcn3 and Clcn6 ) and the intracellular ( Clic1 ) subtypes. Regarding the pore-forming alpha-1 subunits of voltage-gated calcium channels, two ( Cacna1b and Cacna1h ) were upregulated, while Cacna1g showed downregulation. The ancillary subunits were also differentially regulated ( Cacna2d1 , Cacna2d2 , Cacnb1 , Cacnb3 , Cacnb4 , Cacng5 , Cacng6 , and Cacng8 ). In addition, ryanodine receptor 1 ( Ryr1 ) gene was downregulated, while a transient receptor potential cation channel ( Trpm3 ) gene showed enhanced expression. Genes encoding proteins regulating the intracellular calcium homeostasis were also influenced ( Calb1 , Hpca , Hpcal1 , Hpcal4 , Cabp7 , Cab 39l , and Cib2 ). The differential expression of genes coding for ion channel proteins in GnRH neurons at late proestrus indica...

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Genetic Targeting of Green Fluorescent Protein to Gonadotropin-Releasing Hormone Neurons: Characterization of Whole-Cell Electrophysiological Properties and Morphology1

Cited by 198 publications

References 40 publications

Leukemia Inhibitory Factor Represses GnRH Gene Expression via cFOS during Inflammation in Male Mice

Leukemia Inhibitory Factor Represses GnRH Gene Expression via cFOS during Inflammation in Male Mice

Diurnal and estradiol-dependent changes in gonadotropin-releasing hormone neuron firing activity

Proestrus Differentially Regulates Expression of Ion Channel and Calcium Homeostasis Genes in GnRH Neurons of Mice

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