Context: Inflammatory pathways may impair central regulatory networks involving gonadotropin-releasing hormone (GnRH) neuron activity. Studies in humans are limited by the lack of human GnRH neuron cell lines.
Objective: To establish an in vitro model of human GnRH neurons and analyze the effects of proinflammatory cytokines.
Design: The primary human fetal hypothalamic cells (hfHypo) were isolated from 12-week-old fetuses. Responsiveness to kisspeptin, the main GnRH neurons' physiological regulator, was evaluated for biological characterization. Tumor necrosis factor alpha (TNF-α) was used as a proinflammatory stimulus. Main Outcome Measures: Expression of specific GnRH neuron markers by quantitative reverse transcription-polymerase chain reaction, flow cytometry, and immunocytochemistry analyses; and GnRH-releasing ability and electrophysiological changes in response to kisspeptin.
Results: The primary hfHypo showed a high percentage of GnRH-positive cells (80%), expressing a functional kisspeptin receptor (KISS1R) and able to release GnRH in response to kisspeptin. TNF-α exposure determined a specific inflammatory intracellular signaling and reduced GnRH secretion, KISS1R expression, and kisspeptin-induced depolarizing effect. Moreover, hfHypo possessed a primary cilium, whose assembly was inhibited by TNF-α.
Conclusion: The hfHypo cells represent a novel tool for investigations on human GnRH neuron biology. TNF-α directly affects GnRH neuron function by interfering with KISS1R expression and ciliogenesis, thereby impairing kisspeptin signaling.
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http://dx.doi.org/10.1210/jc.2016-2115 | DOI Listing |
J Endocr Soc
January 2025
Cellular and Molecular Endocrinology Laboratory LIM/25, Division of Endocrinology and Metabolism, Clinicas Hospital, School of Medicine, University of Sao Paulo, 01246-903 Sao Paulo, Brazil.
Human puberty is a dynamic biological process determined by the increase in the pulsatile secretion of GnRH triggered by distinct factors not fully understood. Current knowledge reveals fine tuning between an increase in stimulatory factors and a decrease in inhibitory factors, where genetic and epigenetic factors have been indicated as key players in the regulation of puberty onset by distinct lines of evidence. Central precocious puberty (CPP) results from the premature reactivation of pulsatile secretion of GnRH.
View Article and Find Full Text PDFAndrology
January 2025
Section of Endocrinology and Investigative Medicine, Imperial College London, London, UK.
The hypothalamic-pituitary-gonadal axis is regulated by the gonadotropin-releasing hormone pulse generator in the hypothalamus. This is comprised of neurons that secrete kisspeptin in a pulsatile manner to stimulate the release of GnRH, and, in turn, downstream gonadotropins from the pituitary gland, and subsequently sex steroids and gametogenesis from the gonads. Many reproductive disorders in both males and females are characterized by hypothalamic dysfunction, including functional disorders (such as age-related hypogonadism, obesity-related secondary hypogonadism, hyperprolactinemia, functional hypothalamic amenorrhea and polycystic ovary syndrome), structural pathologies (such as craniopharyngiomas or radiation or surgery-related hypothalamic dysfunction), and pubertal disorders (constitutional delay of growth and puberty and congenital hypogonadotropic hypogonadism).
View Article and Find Full Text PDFPhysiol Rev
January 2025
Department of Investigative Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom.
Kisspeptin and neurokinin B (NKB) play a key role in several physiological processes including in puberty, adult reproductive function including the menstrual cycle, as well as mediating the symptoms of menopause. Infundibular kisspeptin neurons, which co-express NKB, regulate the activity of gonadotropin releasing hormone (GnRH) neurons, and thus the physiological pulsatile secretion of GnRH from the hypothalamus. Outside of their hypothalamic reproductive roles, these peptides are implicated in several physiological functions including sexual behavior and attraction, placental function, and bone health.
View Article and Find Full Text PDFElife
January 2025
Department of Physiology, Development and Neuroscience, Downing site, University of Cambridge, Cambridge, United Kingdom.
The gonadotropin-releasing hormone (GnRH) neurons represent the key output cells of the neural network controlling mammalian fertility. We used GCaMP fiber photometry to record the population activity of the GnRH neuron distal projections in the ventral arcuate nucleus where they merge before entering the median eminence to release GnRH into the portal vasculature. Recordings in freely behaving intact male and female mice revealed abrupt ~8 min duration increases in activity that correlated perfectly with the appearance of a subsequent pulse of luteinizing hormone (LH).
View Article and Find Full Text PDFElife
January 2025
Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.
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