scholarly journals Frequency of Impaired Fibroblast Growth Factor Receptor 1 Signaling as a Cause of Normosmic Idiopathic Hypogonadotropic Hypogonadism

2009 ◽  
Vol 23 (12) ◽  
pp. 2120-2121
Author(s):  
Taneli Raivio ◽  
Yisrael Sidis ◽  
Lacey Plummer ◽  
Huaibin Chen ◽  
Jinghong Ma ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Pubertal Development ◽  
Hypogonadotropic Hypogonadism ◽  
Growth Factor Receptor ◽  
Cell Surface Expression ◽  
Heterozygous Mutation ◽  
Loss Of Function ◽  
Idiopathic Hypogonadotropic Hypogonadism ◽  
The Impact

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.

Functional Characteristics of Novel FGFR1 Mutations in Patients with Isolated Gonadotropin-Releasing Hormone Deficiency

2020 ◽  
Author(s):  
Jin-Ho Choi ◽  
Arum Oh ◽  
Yena Lee ◽  
Gu-Hwan Kim ◽  
Han-Wook Yoo
Keyword(s):  
Pubertal Development ◽  
Hypogonadotropic Hypogonadism ◽  
Gonadotropin Releasing Hormone ◽  
Delayed Puberty ◽  
Functional Assay ◽  
Functional Characteristics ◽  
Releasing Hormone ◽  
Phenotypic Spectrum ◽  
The Impact

Abstract Background Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) has a wide phenotypic spectrum including Kallmann syndrome (KS) and normosmic idiopathic hypogonadotropic hypogonadism (nIHH). FGFR1 mutations have been identified in 3–10% of patients with KS or nIHH. This study was performed to investigate clinical phenotypes and functional characteristics of FGFR1 mutations in patients with IGD. Methods This study included 8 patients (from 7 families) with FGFR1 mutations identified by targeted gene panel sequencing or whole exome sequencing (WES). The impact of the identified mutations on FGFR1 function was assessed using in vitro studies. Results Seven heterozygous mutations in FGFR1 were identified in 8 patients from 7 independent families. The patients exhibited a wide spectrum of pubertal development, including anosmia in a prepubertal boy (n=1), delayed puberty (n=2), nIHH (n=3), and KS (n=2). Four of the mutations were classified as likely pathogenic, and the other three were variants of uncertain significance. FGF8-FGFR1 signaling activities for the novel FGFR1 variants (p.Y339H, p.S681I, and p.N185Kfs*16) were reduced by in vitro functional assay, indicating loss-of-function mutations. Conclusions This study identified seven rare sequence variants in FGFR1 in patients with KS and nIHH. Probands with an FGFR1 mutations displayed a wide phenotypic spectrum ranging from KS to anosmia. A prepubertal male with anosmia should be followed up to assess pubertal development because they can manifest hypogonadotropic hypogonadism after puberty. These results expand the phenotypic spectrum of FGFR1 mutations and suggest a broader biologic role of FGFR1 in reproduction.

Abstract P322: Ror2: A Novel Regulator Of Cardiomyocyte Structure And Target Of Right Ventricular Failure

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Jonathan J Edwards ◽  
Keita Uchida ◽  
Swapnil V Shewale ◽  
Nora Yucel ◽  
Emily A Scarborough ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Systolic Dysfunction ◽  
Growth Factor Receptor ◽  
Right Ventricular Failure ◽  
Loss Of Function ◽  
Ventricular Failure ◽  
Human Right ◽  
The Impact

Introduction: We recently identified the fetal noncanonical WNT receptor ROR2 as being re-expressed in human right ventricular failure (RVF), but the myocardial role of ROR2 remains poorly described. Hypothesis: We assessed if ROR2 expression influences cardiomyocyte structure or contributes to RVF pathogenesis. Methods: ROR2 gain- and loss-of-function (ROR2 GOF and ROR2 LOF ) NRVMs were generated using adenoviral-delivered ROR2 cDNA or shRNA and cultured on nanopatterned substrates. NRVM structure was assessed by confocal microscopy (minimum n=3 replicates, >30 cells/condition). NRVM gene expression was characterized by RNAseq. The impact of ROR2 on RV structure and function was assessed using AAV9-mediated cardiac ROR2 delivery, in 4-week old C57BL/6 mice (vs GFP), and echocardiography and hemodynamics (n= 8, 50% male). Results: ROR2 GOF disrupts non-sarcomeric and sarcomeric NRVM structure, exhibiting smaller (500 vs. 711 μm 2 , p = 7.4x10 -23 ) and rounder (aspect ratio 2.1 vs. 3.1, p=1.9x10 -16 ) shape and fragmented sarcomeres (Figure). Whereas, ROR2 LOF NRVMs demonstrate a striking peripheralization of α-actinin and β-catenin. Gene-set enrichment analyses of ROR2 GOF NRVMs reveal upregulation of cytokinesis, mitosis, microtubule regulation, and insulin like growth factor receptor signaling. By 4 weeks after induction of ROR2 GOF in vivo , mice exhibit biventricular dilation and systolic dysfunction (TAPSE 0.85 vs 1.2 mm, p = 2.1x10 -5 ; right ventricular outflow dimension 2.0 vs 1.7 mm, p = 0.001, LV EDV 33.5 vs 28.6 μL, p = 0.05; LV ejection fraction 63% vs 69%, p = 0.015). RV diastolic function is reduced in ROR2 GOF (E:e’ 21.8 vs 18.6, p = 0.004 and RV EDP 2.9 vs 1.0 mmHg, p = 0.06). Conclusions: ROR2 GOF causes biventricular dilation, systolic and diastolic dysfunction in vivo . In vitro, ROR2 GOF NRVMs exhibit an immaturity phenotype with maintenance of proliferation gene program. In contrast, ROR2 LOF NRVMs form a tight monolayer with enhanced cell-cell borders.

scholarly journals Rare variants in KDR, encoding VEGF Receptor 2, are associated with tetralogy of Fallot

2021 ◽  
Author(s):  
Doris Škorić-Milosavljević ◽  
Najim Lahrouchi ◽  
Fernanda M. Bosada ◽  
Gregor Dombrowsky ◽  
Simon G. Williams ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Tetralogy Of Fallot ◽  
Large Scale ◽  
Rare Variants ◽  
Growth Factor Receptor ◽  
Vegf Receptor ◽  
Loss Of Function ◽  
Endothelial Growth Factor

Abstract Purpose Rare genetic variants in KDR, encoding the vascular endothelial growth factor receptor 2 (VEGFR2), have been reported in patients with tetralogy of Fallot (TOF). However, their role in disease causality and pathogenesis remains unclear. Methods We conducted exome sequencing in a familial case of TOF and large-scale genetic studies, including burden testing, in >1,500 patients with TOF. We studied gene-targeted mice and conducted cell-based assays to explore the role of KDR genetic variation in the etiology of TOF. Results Exome sequencing in a family with two siblings affected by TOF revealed biallelic missense variants in KDR. Studies in knock-in mice and in HEK 293T cells identified embryonic lethality for one variant when occurring in the homozygous state, and a significantly reduced VEGFR2 phosphorylation for both variants. Rare variant burden analysis conducted in a set of 1,569 patients of European descent with TOF identified a 46-fold enrichment of protein-truncating variants (PTVs) in TOF cases compared to controls (P = 7 × 10-11). Conclusion Rare KDR variants, in particular PTVs, strongly associate with TOF, likely in the setting of different inheritance patterns. Supported by genetic and in vivo and in vitro functional analysis, we propose loss-of-function of VEGFR2 as one of the mechanisms involved in the pathogenesis of TOF.

scholarly journals Liver X Receptor Nuclear Receptors Are Transcriptional Regulators of Dendritic Cell Chemotaxis

2018 ◽  
Vol 38 (10) ◽  
Author(s):  
Susana Beceiro ◽  
Attila Pap ◽  
Zsolt Czimmerer ◽  
Tamer Sallam ◽  
Jose A. Guillén ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Low Density Lipoprotein ◽  
Myeloid Cells ◽  
Density Lipoprotein ◽  
Loss Of Function ◽  
Transcriptional Responses ◽  
Cd38 Expression ◽  
The Impact

ABSTRACTThe liver X receptors (LXRs) are ligand-activated nuclear receptors with established roles in the maintenance of lipid homeostasis in multiple tissues. LXRs exert additional biological functions as negative regulators of inflammation, particularly in macrophages. However, the transcriptional responses controlled by LXRs in other myeloid cells, such as dendritic cells (DCs), are still poorly understood. Here we used gain- and loss-of-function models to characterize the impact of LXR deficiency on DC activation programs. Our results identified an LXR-dependent pathway that is important for DC chemotaxis. LXR-deficient mature DCs are defective in stimulus-induced migrationin vitroandin vivo. Mechanistically, we show that LXRs facilitate DC chemotactic signaling by regulating the expression of CD38, an ectoenzyme important for leukocyte trafficking. Pharmacological or genetic inactivation of CD38 activity abolished the LXR-dependent induction of DC chemotaxis. Using the low-density lipoprotein receptor-deficient (LDLR−/−) LDLR−/−mouse model of atherosclerosis, we also demonstrated that hematopoietic CD38 expression is important for the accumulation of lipid-laden myeloid cells in lesions, suggesting that CD38 is a key factor in leukocyte migration during atherogenesis. Collectively, our results demonstrate that LXRs are required for the efficient emigration of DCs in response to chemotactic signals during inflammation.

Idiopathic hypogonadotropic hypogonadism: a rare cause of primary amenorrhoea in adolescence—a review and update on diagnosis, management and advances in genetic understanding.

2021 ◽  
Vol 14 (4) ◽  
pp. e239495
Author(s):  
Grace Cham ◽  
Brooke O'Brien ◽  
Rebecca MN Kimble
Keyword(s):  
Genetic Disorders ◽  
Pubertal Development ◽  
Hypogonadotropic Hypogonadism ◽  
Gene Mutations ◽  
Serum Levels ◽  
Breast Development ◽  
Idiopathic Hypogonadotropic Hypogonadism ◽  
Primary Amenorrhoea ◽  
Normal Menstrual Cycle ◽  
Uterine Growth

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.

Cellworks Omics Biology Model (CBM) to predict therapy response and identify biomarkers for all-trans retinoic acid (ATRA) benefit as addition to induction chemotherapy in adults with acute myeloid leukemia (AML).

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 7027-7027
Author(s):  
Scott C. Howard ◽  
Ansu Kumar ◽  
Himanshu Grover ◽  
Vivek Patil ◽  
Ashish Agrawal ◽  
...  
Keyword(s):  
Computational Modeling ◽  
A Priori ◽  
Therapy Response ◽  
Initial Therapy ◽  
Specific Protein ◽  
Loss Of Function ◽  
Monosomy 7 ◽  
All Trans Retinoic Acid ◽  
The Impact

7027 Background: ATRA combined with arsenic trioxide revolutionized the treatment of APL. Based on promising in vitro data, several clinical trials evaluated ATRA combinations in non-APL AML, in which some patients seemed to benefit from the addition. Thus, predicting response a priori is imperative to determine the optimal treatment for each patient. The CBM was used to evaluate the impact of initial therapy with ATRA combined with cytarabine, etoposide, idarubicin (ATRA-CEI) to assess the biomarkers responsible for response in adults with AML. Methods: AML patients participating in clinical trial NCT00151242 had their leukemia sequenced as part of the trial, and genomic profiles were used for computational modeling by the CBM, which uses curated data about genomic aberrations from PubMed as input to generate disease-specific protein network maps and predict drug responses. Disease biomarkers unique to each patient were identified using biosimulation. Digital drug simulations were conducted by measuring the effect of ATRA-CEI on a composite cell growth score of cell proliferation, apoptosis and other hallmarks of cancer. ATRA-CEI was mapped to the patient genome along with a mechanism of action and validated based on the genomic profile and its biological consequences. Results: Of 171 patients treated with ATRA-CEI, 107 (63%) responded (R) and 64 did not (NR). A subset of 18 patients with favorable genomic features were found to be NR and their non-response was correctly predicted by CBM in all 18 cases. Mutations of DNMT3A, EZH2, ASXL, FLT-3, and GART amplification emerged as novel biomarkers of ATRA-CEI failure (only 37 of 107 responders (35%) with these findings, compared to 70 of 107 responders (65%) without these findings (p = 0.0027)). DNMT3A, EZH2, ASXL1 loss of function mutations activate FABP5, a key mechanism of ATRA resistance, and also activate ABCC1 (PgP), which reduces the efficacy of etoposide and idarubicin by upregulating MDR1. In general, monosomy 7 is expected to confer ATRA resistance due to the presence of EZH2 and KMT2E gene deletions. Indeed, 18 of 32 patients with monosomy 7 did not respond. However, the 14 who responded had co-occurrence of deletions involving IGFBP3, PMS2, HUS1, CDK5, XRCC2/4, AKR1B10, and others that overcame ATRA resistance associated with monosomy 7 and were identified by CBM. Use of CBM helps avoid unnecessary use of ATRA in patients unlikely to respond (19% of cases) thus reducing toxicity and cost without changing efficacy, and also identifies those likely to respond, even when they have monosomy 7, where non-response is the norm. Conclusions: ATRA benefits a subset of patients with non-APL AML. CBM predicted response using computational modeling of all genetic alternations, which explains its success versus traditional one-gene-one-drug approaches.

Opposing functions of β-arrestin 1 and 2 in Parkinson’s disease via microglia inflammation and Nprl3

2020 ◽  
Author(s):  
Yinquan Fang ◽  
Qingling Jiang ◽  
Shanshan Li ◽  
Hong Zhu ◽  
Xiao Ding ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Mouse Models ◽  
Inflammatory Responses ◽  
Microglia Activation ◽  
Loss Of Function ◽  
Neuron Loss ◽  
Primary Mouse ◽  
The Impact

Abstract Background Although β-arrestins (ARRBs) regulate diverse physiological and pathophysiological processes, their function and regulation in Parkinson’s disease (PD) remain poorly defined. Methods We measured expression of ARRB1 and ARRB2 in liposaccharide (LPS)-induced and 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced PD mice. ARRB1-deficient and ARRB2-deficient mouse were used to assess the impact of ARRBs on dopaminergic (DA) neuron loss and microglia activation in PD mouse models. After primary mouse DA neurons were exposed to the conditioned medium from ARRB1 knockdown or ARRB2 knockout microglia stimulated by LPS plus interferon γ (IFN-γ), the degeneration of DA neurons was quantified. Gain- and loss-of-function studies were used to study the effects of ARRBs on microglia activation in vitro. To further understand the mechanism, we measured the activation of classical inflammatory pathways and used RNA sequencing to identify the novel downstream effector of ARRBs. Result In this study, we demonstrate that expression of ARRB1 and ARRB2, particularly in microglia, is reciprocally regulated in PD mouse models. ARRB1 ablation ameliorates, whereas ARRB2 knockout aggravates, the pathological features of PD, including DA neuron loss, neuroinflammation and microglia activation in vivo, as well as microglia-mediated neuron damage and inflammation in vitro. In parallel, ARRB1 and ARRB2 produce adverse effects on the activation of inflammatory signal transducers and activators of transcription 1 (STAT1) and nuclear factor-κB (NF-κB) pathways in microglia. We also show that two ARRBs competitively interact with activated p65 in the NF-κB pathway and that nitrogen permease regulator-like 3 (Nprl3), a functionally poorly characterized protein, is a novel effector acting downstream of both ARRBs. Conclusion Collectively, these data demonstrate that two closely related ARRBs have completely opposite functions in microglia-mediated inflammatory responses, via Nprl3, and differentially affect the pathogenesis of PD, and suggest a potential therapeutic strategy.

scholarly journals Influence of Ferroportin Disease Mutations on Manganese Accumulation and Toxicity (P24-060-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Eun-kyung Choi ◽  
Young-Ah Seo
Keyword(s):  
Genetic Disorder ◽  
Functional Results ◽  
Site Directed Mutagenesis ◽  
Loss Of Function ◽  
Gene Encoding ◽  
Excess Iron ◽  
Funding Sources ◽  
Disease Mutations ◽  
The Impact

Abstract Objectives Hemochromatosis is a frequent genetic disorder characterized by the accumulation of excess iron across tissues. Mutations in the FPN1 gene, encoding a cell-surface iron exporter ferroportin (Fpn), are responsible for hemochromatosis type 4, also known as ferroportin disease. Recently, Fpn has been implicated in the regulation of manganese (Mn), another essential nutrient required for numerous cellular enzymes. However, the roles of Fpn in Mn regulation remain ill defined, and the impact of disease mutations on cellular Mn levels is unknown. Thus, this study aimed to define the role of Fpn in Mn regulation and determine the functional consequences of ferroportin disease mutations in cellular Mn levels. Methods Thus far, over 50 mutations in Fpn have been identified in hemochromatosis type 4/ferroportin disease. To test whether these mutations alter cellular Mn metabolism, we constructed an expression vector encoding human Fpn with a C-terminal HA epitope tag and introduced nine clinically relevant mutations by site-directed mutagenesis. Based on previously reported in vitro functional results, we selected five ferroportin disease mutations from each of the two groups: five loss-of-function (LOF) mutations (G80S, R88G, D157G, D157Y, and V162Δ) and four gain-of-function (GOF) mutations (N144H, N144T, C326S, and and S338R). Results Here, we provide evidence that Fpn can export Mn from cells into extracellular space. Fpn appears to play protective roles in Mn-induced cellular toxicity and oxidative stress. Finally, disease mutations interfere with Fpn's role in controlling Mn levels as well as the stability of Fpn. Conclusions These results define the function of Fpn as an exporter of both iron and Mn and highlight the potential involvement of Mn dysregulation in ferroportin disease. Funding Sources National Institutes of Health (NIH) to Y.A.S. (K99/R00 ES024340).

scholarly journals Evolutionary Conservation of MKRN3 and Other Makorins and Their Roles in Puberty Initiation and Endocrine Functions

2019 ◽  
Vol 37 (04) ◽  
pp. 166-173 ◽  
Author(s):  
Lydie Naulé ◽  
Ursula B. Kaiser
Keyword(s):  
Wide Spectrum ◽  
Pubertal Timing ◽  
Pubertal Development ◽  
Protein Structures ◽  
Ring Finger ◽  
Central Precocious Puberty ◽  
Evolutionary Conservation ◽  
Loss Of Function ◽  
Underlying Mechanisms

AbstractPuberty is a critical period of development regulated by genetic, nutritional, and environmental factors. The role of makorin ring finger protein 3 (MKRN3) in the regulation of pubertal timing was revealed when loss-of-function mutations were identified in patients with central precocious puberty (CPP). To date, MKRN3 mutations are the most common known genetic cause of CPP. MKRN3 is a member of the makorin family of ubiquitin ligases, together with MKRN1 and MKRN2. The Mkrn genes have been identified in both vertebrates and invertebrates and show high evolutionary conservation of their gene and protein structures. While the existence of Mkrn orthologues in a wide spectrum of species suggests a vital cellular role of the makorins, their role in puberty initiation and endocrine functions is just beginning to be investigated. In this review, we discuss recent studies that have shown the involvement of Mkrn3 and other makorins in the regulation of pubertal development and other endocrine functions, including metabolism and fertility, as well as their underlying mechanisms of action.

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