scholarly journals Inactivating NHLH2 Variants Cause Idiopathic Hypogonadotropic Hypogonadism and Obesity in Humans

Author(s):  
A. Kemal Topaloglu ◽  
Enver Simsek ◽  
Matthew A. Kocher ◽  
Jamala Mammadova ◽  
Ece Bober ◽  
...  

Abstract Metabolism has a role in determining the time of pubertal development and fertility. Nonetheless, molecular/cellular pathways linking metabolism/body weight to puberty/reproduction are unknown. The KNDy (Kisspeptin/Neurokinin B/Dynorphin) neurons in the arcuate (ARC) nucleus of the hypothalamus constitute the GnRH (Gonadotrophin-releasing hormone) pulse generator. We previously created a mouse model with a whole-body targeted deletion of nescient helix-loop-helix 2 (Nhlh2; N2KO), a class II member of the basic helix-loop-helix (bHLH) family of transcription factors. As this mouse model features pubertal failure and late-onset obesity, we wanted to study whether NHLH2 represents a candidate molecule to link metabolism and puberty in the hypothalamus. Exome sequencing of a large Idiopathic Hypogonadotropic Hypogonadism (IHH) cohort revealed obese patients with rare sequence variants in NHLH2, which were characterized by in silico protein analysis, chromatin immunoprecipitation, and luciferase reporter assays. In vitro heterologous expression studies demonstrated that the variant p.R79C impairs Nhlh2 binding to the Mc4r promoter. Furthermore, p.R79C and other variants show impaired transactivation of the human KISS1 promoter. These are the first inactivating human variants that support NHLH2’s critical role in human puberty and body weight control. Failure to carry out this function results in the absence of pubertal development and late-onset obesity in humans.

2021 ◽  
Vol 14 (4) ◽  
pp. e239495
Author(s):  
Grace Cham ◽  
Brooke O'Brien ◽  
Rebecca MN Kimble

Idiopathic hypogonadotropic hypogonadism (IHH) refers to a family of genetic disorders that affect the production and/or action of gonadotropic-releasing hormone, resulting in reduced serum levels of sex steroids. This condition has a prevalence of 1–10 cases/100 000 births and is characterised by the absence of spontaneous pubertal development. In women, the condition is characterised by the onset of normal adrenarche, with the absence of thelarche and menarche. Pubertal induction for breast development and uterine growth with oestradiol, and sequential maintenance of a normal menstrual cycle and adequate oestrogen for bone health, with an oestrogen and progesterone, is considered first-line treatment. Pregnancy can be achieved in patients who have received and responded to treatment with ovulation induction with exogenous gonadotrophins. Advances in genetic testing have led to increased research and understanding of the underlying genetics of IHH with gene mutations described in up to 50% of all IHH cases.


2014 ◽  
Vol 99 (12) ◽  
pp. E2762-E2771 ◽  
Author(s):  
Yee-Ming Chan ◽  
Margaret F. Lippincott ◽  
James P. Butler ◽  
Valerie F. Sidhoum ◽  
Cindy X. Li ◽  
...  

Context: Idiopathic hypogonadotropic hypogonadism (IHH) results from defective synthesis, secretion, or action of GnRH. Kisspeptin is a potent stimulus for GnRH secretion. Objective: We probed the functional capacity of the GnRH neuronal network in patients with IHH. Participants: Eleven subjects with congenital IHH (9 men and 2 women) and one male subject who underwent reversal of IHH were studied. Six of the twelve subjects had an identified genetic cause of their IHH: KAL1 (n = 1), FGFR1 (n = 3), PROKR2 (n = 1), GNRHR (n = 1). Intervention: Subjects underwent q10 min blood sampling to measure GnRH-induced LH secretion at baseline and in response to intravenous boluses of kisspeptin (0.24 nmol/kg) and GnRH (75 ng/kg) both pre- and post-six days of treatment with exogenous GnRH (25 ng/kg sc every 2 h). Results: All subjects with abiding IHH failed to demonstrate a GnRH-induced LH response to exogenous kisspeptin. In contrast, the subject who achieved reversal of his hypogonadotropism demonstrated a robust response to kisspeptin. Conclusions: The functional capacity of the GnRH neuronal network in IHH patients is impaired, as evidenced by their inability to respond to the same dose of kisspeptin that effects a robust GnRH-induced LH response in healthy men and luteal-phase women. This impairment is observed across a range of genotypes, suggesting that it reflects a fundamental property of GnRH neuronal networks that have not been properly engaged during pubertal development. In contrast, a patient who had experienced reversal of his hypogonadotropism responded to exogenous kisspeptin.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5166-5166
Author(s):  
Oktawiusz Wiecha ◽  
Witold Miezynski ◽  
Leszek Wojakiewicz ◽  
Anna Zebzda ◽  
Anna Wedrychowicz ◽  
...  

Abstract Graft versus host disease (GvHD) is still a very serious problem in hematopoietic stem cells transplantation which makes searching for new possibilities of its prevention and treatment necessary. Animal models are very useful tools for such research. We present a mouse model of GvHD allowing observation of both acute and chronic phase of the disease. C57Bl/6 mice (H-2b) were transplanted, one day after ablative TBI with 5×106 BM cells and 4×106 or 10×106 splenocytes isolated from allogeneic C3H. He (H-2k) or from syngeneic animals. Sex mismatched transplants were performed and chimerism of transplanted animals was confirmed by detection of sry gene with PCR. As a control group for blood examination after transplantation C3H syngeneic transplantations were performed. After transplantation, mice were weighted and physically examined by looking for changes in skin, posture, physical activity and peripheral blood parameters. Histopathological examination was performed on day +8, +16, +31 in some of the animals. Autopsy was also performed on mice which died during the experiment or which body weight decreased below 65% of the initial weight. We observed a characteristic pattern of physical symptoms of GvHD including weight loss, skin desquamation, hunching and loss of activity, diarrhea. Weight loss to 88.2% of the initial body weight on day +7 was followed by a return to the initial weight (101.1%) on day +14 and then another decrease either strong and leading to the death of the animal or moderate and leading to a long time plateau (the average body weight on days +31, +59 and +101 was 94.4%, 91.7% and 93.6%). On day +7 desquamation of the skin of paws was very well visible and since day +10 gradually intensifying desquamative changes of the skin of whole body were observed - the mean level of changes in the population was highest on days +21 to + 24. Interestingly areas of the skin which were nude before TBI and transplantation were affected earlier (changes were visible on day +7) and more severly than other regions of the skin suggesting that local more intensive damage caused by irradiation can locally aggravate the course of GvHD. The physical symptoms were accompanied with histopathological changes of liver, skin, spleen and gut. Neither physical nor histopathological symptoms of the disease were observed in mice transplanted with syngeneic cells. In fluorocytometric analysis of peripherial blood performed on days +17, +31 and +45 severe lymphopenia was observed. The average number of CD3+CD4+, CD3+CD8+ and B220+ cells was strongly decreased in animals transplanted with allogeneic cells as compared to syngeneic graft recipients. At the same time expression of CD69 activation antigen on CD4+ and CD8+ cells was strongly increased in allograft recipients as compared to syngeneic controls. The course of the disease, including weight loss and skin changes, was generally less severe in the population of mice transplanted with BM + 4×106 splenocytes as compared to BM + 10×106 of splenocytes recipients. The 25th, 50th and 75th percentiles of survival function for both populations were162, 301, 405 and 45, 88, 277 days, respectively.


2020 ◽  
Vol 24 (1) ◽  
pp. 103-116
Author(s):  
Na Wang ◽  
Min Chen ◽  
Zhen Ni ◽  
Ting Li ◽  
Jiaoxia Zeng ◽  
...  

Abstract Background Gastric intestinal metaplasia (IM) is considered a precancerous lesion, and bile acids (BA) play a critical role in the induction of IM. Ectopic expression of HNF4α was observed in a BA-induced IM cell model. However, the mechanisms underlying the upregulation of the protein in IM cells remains to be elucidated. Methods The effects of HNF4α on gastric mucosal cells in vivo were identified by a transgenic mouse model and RNA-seq was used to screen downstream targets of deoxycholic acid (DCA). The expression of pivotal molecules and miR-1 was detected by immunohistochemistry and in situ hybridization in normal, gastritis and IM tissue slides or microarrays. The transcriptional regulation of HDAC6 was investigated by chromatin immunoprecipitation (ChIP) and luciferase reporter assays. Results The transgenic mouse model validated that HNF4α stimulated the HDAC6 expression and mucin secretion in gastric mucosa. Increased HDAC6 and HNF4α expression was also detected in the gastric IM cell model and patient specimens. HNF4α could bind to and activate HDAC6 promoter. In turn, HDAC6 enhanced the HNF4α protein level in GES-1 cells. Furthermore, miR-1 suppressed the expression of downstream intestinal markers by targeting HDAC6 and HNF4α. Conclusions Our findings show that the HDAC6/HNF4α loop regulated by miR-1 plays a critical role in gastric IM. Blocking the activation of this loop could be a potential approach to preventing BA-induced gastric IM or even gastric cancer (GC).


2009 ◽  
Vol 23 (12) ◽  
pp. 2120-2121
Author(s):  
Taneli Raivio ◽  
Yisrael Sidis ◽  
Lacey Plummer ◽  
Huaibin Chen ◽  
Jinghong Ma ◽  
...  

ABSTRACT Context FGFR1 mutations have been identified in about 10% of patients with Kallmann syndrome. Recently cases of idiopathic hypogonadotropic hypogonadism (IHH) with a normal sense of smell (nIHH) have been reported. Aims The objective of the study was to define the frequency of FGFR1 mutations in a large cohort of nIHH, delineate the spectrum of reproductive phenotypes, assess functionality of the FGFR1 mutant alleles in vitro, and investigate genotype-phenotype relationships. Design FGFR1 sequencing of 134 well-characterized nIHH patients (112 men and 22 women) and 270 healthy controls was performed. The impact of the identified mutations on FGFR1 function was assessed using structural prediction and in vitro studies. Results Nine nIHH subjects (five males and four females; 7%) harbor a heterozygous mutation in FGFR1 and exhibit a wide spectrum of pubertal development, ranging from absent puberty to reversal of IHH in both sexes. All mutations impair receptor function. The Y99C, Y228D, and I239T mutants impair the tertiary folding, resulting in incomplete glycosylation and reduced cell surface expression. The R250Q mutant reduces receptor affinity for FGF. The K618N, A671P, and Q680X mutants impair tyrosine kinase activity. However, the degree of functional impairment of the mutant receptors did not always correlate with the reproductive phenotype, and variable expressivity of the disease was noted within family members carrying the same FGFR1 mutation. These discrepancies were partially explained by additional mutations in known IHH loci. Conclusions Loss-of-function mutations in FGFR1 underlie 7% of nIHH with different degrees of impairment in vitro. These mutations act in concert with other gene defects in several cases, consistent with oligogenicity.


2016 ◽  
Vol 229 (2) ◽  
pp. 109-122 ◽  
Author(s):  
Brenton T Laing ◽  
Khoa Do ◽  
Tomoko Matsubara ◽  
David W Wert ◽  
Michael J Avery ◽  
...  

Exercise plays a critical role in regulating glucose homeostasis and body weight. However, the mechanism of exercise on metabolic functions associated with the CNS has not been fully understood. C57BL6 male mice (n=45) were divided into three groups: normal chow diet, high-fat diet (HFD) treatment, and HFD along with voluntary running wheel exercise training for 12 weeks. Metabolic function was examined by the Comprehensive Lab Animal Monitoring System and magnetic resonance imaging; phenotypic analysis included measurements of body weight, food intake, glucose and insulin tolerance tests, as well as insulin and leptin sensitivity studies. By immunohistochemistry, the amount changes in the phosphorylation of signal transducer and activator of transcription 3, neuronal proliferative maker Ki67, apoptosis positive cells as well as pro-opiomelanocortin (POMC)-expressing neurons in the arcuate area of the hypothalamus was identified. We found that 12 weeks of voluntary exercise training partially reduced body weight gain and adiposity induced by an HFD. Insulin and leptin sensitivity were enhanced in the exercise training group verses the HFD group. Furthermore, the HFD-impaired POMC-expressing neuron is remarkably restored in the exercise training group. The restoration of POMC neuron number may be due to neuroprotective effects of exercise on POMC neurons, as evidenced by altered proliferation and apoptosis. In conclusion, our data suggest that voluntary exercise training improves metabolic symptoms induced by HFD, in part through protected POMC-expressing neuron from HFD and enhanced leptin signaling in the hypothalamus that regulates whole-body energy homeostasis.


2009 ◽  
Vol 55 (5) ◽  
pp. 19-23 ◽  
Author(s):  
Nina Viktorovna Bolotova ◽  
Nadezhda Yur'evna Raygorodskaya

This paper presents results of examination of 59 boys aged from 14 to 16 years with delayed sexual development (DSP). All children were allocated to 3 groups depending on specific clinical features of the disorder. Group 1 comprised boys (n = 20) with retardation of growth and sexual development, group 2 (n = 14) boys with DSP and cryptorchidism, group 3 (n = 25) boys with DSP and obesity. The examination included evaluation of the patients' physical and pubertal development, measurement of serum sex hormones, and difereline stimulation test. Constitutional form of DSP was diagnosed in 90% of the boys in group 1. Hypogonadotropic hypogonadism occurred in 42.8% of the patients in group 2, and boys of group 3 suffered DSP etiologically associated with excessive body weight. It is concluded that correlation between clinical and hormonal characteristics of the examined boys reflects the cause behind DSP.


2010 ◽  
Vol 95 (6) ◽  
pp. 2836-2840 ◽  
Author(s):  
Pamela Fischer-Posovszky ◽  
Julia von Schnurbein ◽  
Barbara Moepps ◽  
Georgia Lahr ◽  
Gudrun Strauss ◽  
...  

Abstract Objective: Leptin, a protein product of adipocytes, plays a critical role in the regulation of body weight, immune function, pubertal development, and fertility. So far, only three homozygous mutations in the leptin gene in a total of 13 individuals have been found leading to a phenotype of extreme obesity with marked hyperphagia and impaired immune function. Design: Serum leptin was measured by ELISA. The leptin gene (OB) was sequenced in patient DNA. The effect of the identified novel mutation was assessed using HEK293 cells. Results: We describe a 14-yr-old child of nonobese Austrian parents without known consanguinity. She had a body mass index of 31.5 kg/m2 (+2.46 sd score) and undetectable leptin serum levels. Sequencing of the leptin gene revealed a hitherto unknown homozygous transition (TTA to TCA) in exon 3 of the LEP gene resulting in a L72S replacement in the leptin protein. RT-PCR, Western blot, and immunohistochemical analysis indicated that the mutant leptin was expressed in the patient’s adipose tissue but retained within the cell. Using a heterologous cell system, we confirmed this finding and demonstrated that the side chain of Leu72 is crucial for intracellular leptin trafficking. Our patient showed signs of a hypogonadotropic hypogonadism. However, in contrast to the literature, she showed only mild obesity and a normal T cell responsiveness. Conclusions: These findings shed a new light on the clinical consequences of leptin deficiency. Congenital leptin deficiency should be considered possible in pediatric patients with mild obesity even if parents are lean and unrelated.


Cell Cycle ◽  
2018 ◽  
Vol 17 (19-20) ◽  
pp. 2321-2334 ◽  
Author(s):  
Chinthalapally V. Rao ◽  
Mudassir Farooqui ◽  
Adam S. Asch ◽  
Hiroshi Y. Yamada

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