1
|
Guijo B, Argente J, Martos-Moreno GÁ. The N221D variant in PCSK1 is highly prevalent in childhood obesity and can influence the metabolic profile. J Pediatr Endocrinol Metab 2023; 36:1140-1145. [PMID: 37877373 DOI: 10.1515/jpem-2023-0395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/09/2023] [Indexed: 10/26/2023]
Abstract
OBJECTIVES To study the prevalence and influence on metabolic profile of the prohormone-convertase-1 (PCSK1) N221D variant in childhood obesity, proven its role in the leptin-melanocortin signaling pathway as in proinsulin and other prohormone cleavage. METHODS Transversal study of 1066 children with obesity (mean age and BMI Z-score 10.38 ± 3.44 years and +4.38 ± 1.77, respectively), 51.4 % males, 54.4 % prepubertal, 71.5 % Caucasians and 20.8 % Latinos. Anthropometric and metabolic features were compared between patients carrying the N221D variant in PCSK1 and patients with no variants found after next generation sequencing analysis of 17 genes (CREBBP, CPE, HTR2C, KSR2, LEP, LEPR, MAGEL2, MC3R, MC4R, MRAP2, NCOA1, PCSK1, POMC, SH2B1, SIM1, TBX3 and TUB) involved in the leptin-melanocortin pathway. RESULTS No variants were found in 531 patients (49.8 %), while 68 patients carried the PCSK1 N221D variant (42 isolately, and 26 with at least one additional gene variant). Its prevalence was higher in Caucasians vs. Latinos (χ2 7.81; p<0.01). Patients carrying exclusively the PCSK1 N221D variant (n=42) showed lower insulinemia (p<0.05), HOMA index (p<0.05) and area under the curve for insulin in the oral glucose tolerance test (p<0.001) and higher WBISI (p<0.05) than patients with no variants, despite similar obesity severity, age, sex and ethnic distribution. CONCLUSIONS The N221D variant in PCSK1 is highly prevalent in childhood obesity, influenced by ethnicity. Indirect estimation of insulin resistance, based on insulinemia could be byassed in these patients and underestimate their type 2 diabetes mellitus risk.
Collapse
Affiliation(s)
- Blanca Guijo
- Departments of Pediatrics and Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Madrid, Spain
| | - Jesús Argente
- Departments of Pediatrics and Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Madrid, Spain
- Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
- Instituto de alimentación IMDEA, CEIUAM+CSIC, Madrid, Spain
| | - Gabriel Ángel Martos-Moreno
- Departments of Pediatrics and Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Madrid, Spain
- Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| |
Collapse
|
2
|
Štepihar D, Florke Gee RR, Hoyos Sanchez MC, Fon Tacer K. Cell-specific secretory granule sorting mechanisms: the role of MAGEL2 and retromer in hypothalamic regulated secretion. Front Cell Dev Biol 2023; 11:1243038. [PMID: 37799273 PMCID: PMC10548473 DOI: 10.3389/fcell.2023.1243038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/31/2023] [Indexed: 10/07/2023] Open
Abstract
Intracellular protein trafficking and sorting are extremely arduous in endocrine and neuroendocrine cells, which synthesize and secrete on-demand substantial quantities of proteins. To ensure that neuroendocrine secretion operates correctly, each step in the secretion pathways is tightly regulated and coordinated both spatially and temporally. At the trans-Golgi network (TGN), intrinsic structural features of proteins and several sorting mechanisms and distinct signals direct newly synthesized proteins into proper membrane vesicles that enter either constitutive or regulated secretion pathways. Furthermore, this anterograde transport is counterbalanced by retrograde transport, which not only maintains membrane homeostasis but also recycles various proteins that function in the sorting of secretory cargo, formation of transport intermediates, or retrieval of resident proteins of secretory organelles. The retromer complex recycles proteins from the endocytic pathway back to the plasma membrane or TGN and was recently identified as a critical player in regulated secretion in the hypothalamus. Furthermore, melanoma antigen protein L2 (MAGEL2) was discovered to act as a tissue-specific regulator of the retromer-dependent endosomal protein recycling pathway and, by doing so, ensures proper secretory granule formation and maturation. MAGEL2 is a mammalian-specific and maternally imprinted gene implicated in Prader-Willi and Schaaf-Yang neurodevelopmental syndromes. In this review, we will briefly discuss the current understanding of the regulated secretion pathway, encompassing anterograde and retrograde traffic. Although our understanding of the retrograde trafficking and sorting in regulated secretion is not yet complete, we will review recent insights into the molecular role of MAGEL2 in hypothalamic neuroendocrine secretion and how its dysregulation contributes to the symptoms of Prader-Willi and Schaaf-Yang patients. Given that the activation of many secreted proteins occurs after they enter secretory granules, modulation of the sorting efficiency in a tissue-specific manner may represent an evolutionary adaptation to environmental cues.
Collapse
Affiliation(s)
- Denis Štepihar
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Rebecca R. Florke Gee
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Maria Camila Hoyos Sanchez
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Klementina Fon Tacer
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| |
Collapse
|
3
|
Folon L, Baron M, Toussaint B, Vaillant E, Boissel M, Scherrer V, Loiselle H, Leloire A, Badreddine A, Balkau B, Charpentier G, Franc S, Marre M, Aboulouard S, Salzet M, Canouil M, Derhourhi M, Froguel P, Bonnefond A. Contribution of heterozygous PCSK1 variants to obesity and implications for precision medicine: a case-control study. Lancet Diabetes Endocrinol 2023; 11:182-190. [PMID: 36822744 DOI: 10.1016/s2213-8587(22)00392-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 02/24/2023]
Abstract
BACKGROUND Rare biallelic pathogenic mutations in PCSK1 (encoding proprotein convertase subtilisin/kexin type 1 [PC1/3]) cause early-onset obesity associated with various endocrinopathies. Setmelanotide has been approved for carriers of these biallelic mutations in the past 3 years. We aimed to perform a large-scale functional genomic study focusing on rare heterozygous variants of PCSK1 to decipher their putative impact on obesity risk. METHODS This case-control study included all participants with overweight and obesity (ie, cases) or healthy weight (ie, controls) from the RaDiO study of three community-based and one hospital-based cohort in France recruited between Jan 1, 1995, and Dec 31, 2000. In adults older than 18 years, healthy weight was defined as BMI of less than 25·0 kg/m2, overweight as 25·0-29·9 kg/m2, and obesity as 30·0 kg/m2 or higher. Participants with type 2 diabetes had fasting glucose of 7·0 mmol/L or higher or used treatment for hyperglycaemia (or both) and were negative for islet or insulin autoantibodies. Functional assessment of rare missense variants of PCSK1 was performed. Pathogenicity clusters of variants were determined with machine learning. The effect of each cluster of PCSK1 variants on obesity was assessed using the adjusted mixed-effects score test. FINDINGS All 13 coding exons of PCSK1 were sequenced in 9320 participants (including 7260 adults and 2060 children and adolescents) recruited from the RaDiO study. We detected 65 rare heterozygous PCSK1 variants, including four null variants and 61 missense variants that were analysed in vitro and clustered into five groups (A-E), according to enzymatic activity. Compared with the wild-type, 15 missense variants led to complete PC1/3 loss of function (group A; reference) and rare exome variant ensemble learner (REVEL) led to 15 (25%) false positives and four (7%) false negatives. Carrying complete loss-of-function or null PCSK1 variants was significantly associated with obesity (six [86%] of seven carriers vs 1518 [35%] of 4395 non-carriers; OR 9·3 [95% CI 1·5-177·4]; p=0·014) and higher BMI (32·0 kg/m2 [SD 9·3] in carriers vs 27·3 kg/m2 [6·5] in non-carriers; mean effect π 6·94 [SE 1·95]; p=0·00029). Clusters of PCSK1 variants with partial or neutral effect on PC1/3 activity did not have an effect on obesity or overweight and on BMI. INTERPRETATION Only carriers of heterozygous, null, or complete loss-of-function PCSK1 variants cause monogenic obesity and, therefore, might be eligible for setmelanotide. In silico tests were unable to accurately detect these variants, which suggests that in vitro assays are necessary to determine the variant pathogenicity for genetic diagnosis and precision medicine purposes. FUNDING Agence Nationale de la Recherche, European Research Council, National Center for Precision Diabetic Medicine, European Regional Development Fund, Hauts-de-France Regional Council, and the European Metropolis of Lille.
Collapse
Affiliation(s)
- Lise Folon
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Morgane Baron
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Bénédicte Toussaint
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Emmanuel Vaillant
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Mathilde Boissel
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Victoria Scherrer
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Hélène Loiselle
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Audrey Leloire
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Alaa Badreddine
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Beverley Balkau
- Paris-Saclay University, Paris-Sud University, Université de Versailles Saint-Quentin-en-Yvelines, Center for Research in Epidemiology and Population Health, Inserm U1018 Clinical Epidemiology, Villejuif, France
| | - Guillaume Charpentier
- Centre d'Étude et de Recherche pour l'Intensification du Traitement du Diabète, Evry, France
| | - Sylvia Franc
- Centre d'Étude et de Recherche pour l'Intensification du Traitement du Diabète, Evry, France; Department of Diabetes, Sud-Francilien Hospital, Paris-Sud University, Corbeil-Essonnes, France
| | - Michel Marre
- Institut Necker-Enfants Malades, INSERM, Université de Paris, Paris, France; Clinique Ambroise Paré, Neuilly-sur-Seine, France
| | - Soulaimane Aboulouard
- Université de Lille, Lille, France; Inserm U1192, Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse, Lille, France
| | - Michel Salzet
- Université de Lille, Lille, France; Inserm U1192, Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse, Lille, France
| | - Mickaël Canouil
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Mehdi Derhourhi
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Philippe Froguel
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France; Department of Metabolism, Imperial College London, London, UK
| | - Amélie Bonnefond
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France; Department of Metabolism, Imperial College London, London, UK.
| |
Collapse
|
4
|
Shah BP, Sleiman PM, Mc Donald J, Moeller IH, Kleyn P. Functional characterization of all missense variants in LEPR, PCSK1, and POMC genes arising from single-nucleotide variants. Expert Rev Endocrinol Metab 2023; 18:209-219. [PMID: 36864747 DOI: 10.1080/17446651.2023.2179985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 02/09/2023] [Indexed: 02/18/2023]
Abstract
OBJECTIVE Hyperphagia and early-onset, severe obesity are clinical characteristics of rare melanocortin-4 receptor (MC4R) pathway diseases due to loss-of-function (LOF) variants in genes comprising the MC4R pathway. In vitro functional characterization of 12,879 possible exonic missense variants from single-nucleotide variants (SNVs) of LEPR, POMC, and PCSK1 was performed to determine the impact of these variants on protein function. METHODS SNVs of the three genes were transiently transfected into cell lines, and each variant was subsequently classified according to functional impact. We validated three assays by comparing classifications against functional characterization of 29 previously published variants. RESULTS Our results significantly correlated with previously published pathogenic categories (r = 0.623; P = 3.03 × 10-4) of all potential missense variants arising from SNVs. Of all observed variants identified through available databases and a tested cohort of 16,061 patients with obesity, 8.6% of LEPR, 63.2% of PCSK1, and 10.6% of POMC variants exhibited LOF, including variants currently classified as a variant of uncertain significance (VUS). CONCLUSIONS The functional data provided here can assist in the reclassification of several VUS in LEPR, PCSK1, and POMC and highlight their impact in MC4R pathway diseases.
Collapse
Affiliation(s)
- Bhavik P Shah
- Rhythm Pharmaceuticals, Inc, Boston, MA, USA
- Bridgebio Pharma, Palo Alto, CA
| | | | | | - Ida H Moeller
- Rhythm Pharmaceuticals, Inc, Boston, MA, USA
- Sarepta Therapeutics, Cambridge, MA, USA
| | | |
Collapse
|
5
|
Loss of hypothalamic Furin affects POMC to proACTH cleavage and feeding behavior in high-fat diet-fed mice. Mol Metab 2022; 66:101627. [PMID: 36374777 PMCID: PMC9664468 DOI: 10.1016/j.molmet.2022.101627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/23/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE The hypothalamus regulates feeding and glucose homeostasis through the balanced action of different neuropeptides, which are cleaved and activated by the proprotein convertases PC1/3 and PC2. However, the recent association of polymorphisms in the proprotein convertase FURIN with type 2 diabetes, metabolic syndrome, and obesity, prompted us to investigate the role of FURIN in hypothalamic neurons controlling glucose and feeding. METHODS POMC-Cre+/- mice were bred with Furinfl/fl mice to generate conditional knockout mice with Furin-deletion in neurons expressing proopiomelanocortin (POMCFurKO), and Furinfl/fl mice were used as controls. POMCFurKO and controls were periodically monitored on both normal chow diet and high fat diet (HFD) for body weight and glucose tolerance by established in-vivo procedures. Food intake was measured in HFD-fed FurKO and controls. Hypothalamic Pomc mRNA was measured by RT-qPCR. ELISAs quantified POMC protein and resulting peptides in the hypothalamic extracts of POMCFurKO mice and controls. The in-vitro processing of POMC was studied by biochemical techniques in HEK293T and CHO cell lines lacking FURIN. RESULTS In control mice, Furin mRNA levels were significantly upregulated on HFD feeding, suggesting an increased demand for FURIN activity in obesogenic conditions. Under these conditions, the POMCFurKO mice were hyperphagic and had increased body weight compared to Furinfl/fl mice. Moreover, protein levels of POMC were elevated and ACTH concentrations markedly reduced. Also, the ratio of α-MSH/POMC was decreased in POMCFurKO mice compared to controls. This indicates that POMC processing was significantly reduced in the hypothalami of POMCFurKO mice, highlighting for the first time the involvement of FURIN in the cleavage of POMC. Importantly, we found that in vitro, the first stage in processing where POMC is cleaved into proACTH was achieved by FURIN but not by PC1/3 or the other proprotein convertases in cell lines lacking a regulated secretory pathway. CONCLUSIONS These results suggest that FURIN processes POMC into proACTH before sorting into the regulated secretory pathway, challenging the dogma that PC1/3 and PC2 are the only convertases responsible for POMC cleavage. Furthermore, its deletion affects feeding behaviors under obesogenic conditions.
Collapse
|
6
|
Hinney A, Körner A, Fischer-Posovszky P. The promise of new anti-obesity therapies arising from knowledge of genetic obesity traits. Nat Rev Endocrinol 2022; 18:623-637. [PMID: 35902734 PMCID: PMC9330928 DOI: 10.1038/s41574-022-00716-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/17/2022] [Indexed: 02/07/2023]
Abstract
Obesity is a multifactorial and complex disease that often manifests in early childhood with a lifelong burden. Polygenic and monogenic obesity are driven by the interaction between genetic predisposition and environmental factors. Polygenic variants are frequent and confer small effect sizes. Rare monogenic obesity syndromes are caused by defined pathogenic variants in single genes with large effect sizes. Most of these genes are involved in the central nervous regulation of body weight; for example, genes of the leptin-melanocortin pathway. Clinically, patients with monogenic obesity present with impaired satiety, hyperphagia and pronounced food-seeking behaviour in early childhood, which leads to severe early-onset obesity. With the advent of novel pharmacological treatment options emerging for monogenic obesity syndromes that target the central melanocortin pathway, genetic testing is recommended for patients with rapid weight gain in infancy and additional clinical suggestive features. Likewise, patients with obesity associated with hypothalamic damage or other forms of syndromic obesity involving energy regulatory circuits could benefit from these novel pharmacological treatment options. Early identification of patients affected by syndromic obesity will lead to appropriate treatment, thereby preventing the development of obesity sequelae, avoiding failure of conservative treatment approaches and alleviating stigmatization of patients and their families.
Collapse
Affiliation(s)
- Anke Hinney
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy and University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
- Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - Antje Körner
- Leipzig University, Medical Faculty, Hospital for Children and Adolescents, Centre of Paediatric Research (CPL), Leipzig, Germany
- LIFE Child, Leipzig Research Centre for Civilization Diseases, Leipzig, Germany
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany
| | | |
Collapse
|
7
|
Van Dijck E, Beckers S, Diels S, Huybrechts T, Verrijken A, Van Hoorenbeeck K, Verhulst S, Massa G, Van Gaal L, Van Hul W. Rare Heterozygous PCSK1 Variants in Human Obesity: The Contribution of the p.Y181H Variant and a Literature Review. Genes (Basel) 2022; 13:genes13101746. [PMID: 36292633 PMCID: PMC9601648 DOI: 10.3390/genes13101746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 11/16/2022] Open
Abstract
Recently, it was reported that heterozygous PCSK1 variants, causing partial PC1/3 deficiency, result in a significant increased risk for obesity. This effect was almost exclusively generated by the rare p.Y181H (rs145592525, GRCh38.p13 NM_000439.5:c.541T>C) variant, which affects PC1/3 maturation but not enzymatic capacity. As most of the identified individuals with the heterozygous p.Y181H variant were of Belgian origin, we performed a follow-up study in a population of 481 children and adolescents with obesity, and 486 lean individuals. We identified three obese (0.62%) and four lean (0.82%) p.Y181H carriers (p = 0.506) through sanger sequencing and high resulting melting curve analysis, indicating no association with obesity. Haplotype analysis was performed in 13 p.Y181H carriers, 20 non-carriers (10 with obesity and 10 lean), and two p.Y181H families, and showed identical haplotypes for all heterozygous carriers (p < 0.001). Likewise, state-of-the-art literature concerning the role of rare heterozygous PCSK1 variants implies them to be rarely associated with monogenic obesity, as first-degree carrier relatives of patients with PC1/3 deficiency are mostly not reported to be obese. Furthermore, recent meta-analyses have only indicated a robust association for scarce disruptive heterozygous PCSK1 variants with obesity, while clinical significance is less or sometimes lacking for most nonsynonymous variants.
Collapse
Affiliation(s)
- Evelien Van Dijck
- Centre of Medical Genetics, University of Antwerp and Antwerp University Hospital, 2650 Edegem, Belgium
| | - Sigri Beckers
- Centre of Medical Genetics, University of Antwerp and Antwerp University Hospital, 2650 Edegem, Belgium
| | - Sara Diels
- Centre of Medical Genetics, University of Antwerp and Antwerp University Hospital, 2650 Edegem, Belgium
| | - Tammy Huybrechts
- Centre of Medical Genetics, University of Antwerp and Antwerp University Hospital, 2650 Edegem, Belgium
| | - An Verrijken
- Department of Endocrinology, Diabetology and Metabolic Diseases, Antwerp University Hospital, 2650 Edegem, Belgium
| | | | - Stijn Verhulst
- Department of Pediatrics, Antwerp University Hospital, 2650 Edegem, Belgium
| | - Guy Massa
- Department of Pediatrics, Jessa Hospital, 3500 Hasselt, Belgium
| | - Luc Van Gaal
- Department of Endocrinology, Diabetology and Metabolic Diseases, Antwerp University Hospital, 2650 Edegem, Belgium
| | - Wim Van Hul
- Centre of Medical Genetics, University of Antwerp and Antwerp University Hospital, 2650 Edegem, Belgium
- Correspondence: ; Tel.: +32-759-761
| |
Collapse
|
8
|
Meier DT, Rachid L, Wiedemann SJ, Traub S, Trimigliozzi K, Stawiski M, Sauteur L, Winter DV, Le Foll C, Brégère C, Guzman R, Odermatt A, Böni-Schnetzler M, Donath MY. Prohormone convertase 1/3 deficiency causes obesity due to impaired proinsulin processing. Nat Commun 2022; 13:4761. [PMID: 35963866 PMCID: PMC9376086 DOI: 10.1038/s41467-022-32509-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 08/03/2022] [Indexed: 12/12/2022] Open
Abstract
Defective insulin processing is associated with obesity and diabetes. Prohormone convertase 1/3 (PC1/3) is an endopeptidase required for the processing of neurotransmitters and hormones. PC1/3 deficiency and genome-wide association studies relate PC1/3 with early onset obesity. Here, we find that deletion of PC1/3 in obesity-related neuronal cells expressing proopiomelanocortin mildly and transiently change body weight and fail to produce a phenotype when targeted to Agouti-related peptide- or nestin-expressing tissues. In contrast, pancreatic β cell-specific PC1/3 ablation induces hyperphagia with consecutive obesity despite uncontrolled diabetes with glucosuria. Obesity develops not due to impaired pro-islet amyloid polypeptide processing but due to impaired insulin maturation. Proinsulin crosses the blood-brain-barrier but does not induce central satiety. Accordingly, insulin therapy prevents hyperphagia. Further, islet PC1/3 expression levels negatively correlate with body mass index in humans. In this work, we show that impaired PC1/3-mediated proinsulin processing, as observed in human prediabetes, promotes hyperphagic obesity. Defective insulin secretion is observed early in the development of diabetes. Here the authors report that β cell-specific deficiency of the insulin prohormone convertase 1/3 (PC1/3) leads not only to hyperglycemia, but also to hyperphagic obesity in mice.
Collapse
Affiliation(s)
- Daniel T Meier
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland. .,Department of Biomedicine, University of Basel, Basel, Switzerland.
| | - Leila Rachid
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland.,Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Sophia J Wiedemann
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland.,Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Shuyang Traub
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland.,Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Kelly Trimigliozzi
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland.,Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Marc Stawiski
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland.,Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Loïc Sauteur
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Denise V Winter
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, 8057, Zurich, Switzerland
| | - Catherine Brégère
- Department of Biomedicine, University of Basel, Basel, Switzerland.,Department of Neurosurgery, University of Basel, Basel, Switzerland
| | - Raphael Guzman
- Department of Biomedicine, University of Basel, Basel, Switzerland.,Department of Neurosurgery, University of Basel, Basel, Switzerland
| | - Alex Odermatt
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Marianne Böni-Schnetzler
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland.,Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Marc Y Donath
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland.,Department of Biomedicine, University of Basel, Basel, Switzerland
| |
Collapse
|
9
|
Shakya M, Martin NK, Arunagiri A, Martin MG, Arvan P, Low MJ, Lindberg I. The G209R mutant mouse as a model for human PCSK1 polyendocrinopathy. Endocrinology 2022; 163:6542675. [PMID: 35245347 PMCID: PMC9044177 DOI: 10.1210/endocr/bqac024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Indexed: 11/19/2022]
Abstract
PCSK1 encodes an enzyme required for prohormone maturation into bioactive peptides. A striking number of SNPs and rare mutations in PCSK1 are associated with a range of clinical phenotypes. Infants bearing two copies of a catalytically inactivating mutation, such as G209R, exhibit life-threatening chronic diarrhea and subsequently develop systemic endocrinopathies. Using CRISPR/Cas9 technology, we have engineered a mouse model bearing a G209R missense mutation in exon 6 of the murine Pcsk1 locus. Most pups homozygous for the G209R mutation succumbed by day 2, and surviving pups were severely dwarfed. In homozygous (but not heterozygous) pups, blood glucose levels were significantly lower, accompanied by elevated plasma insulin-like immunoreactivity and accumulation of large quantities of unprocessed proinsulin in the pancreas. Peptide hormone processing was also aberrant in G209R mouse pituitary, with mature ACTH levels markedly reduced in homozygotes, accompanied by a significant accumulation of POMC. We also observed a significant reduction in PC1/3 protein in the brains of G209R homozygous mice by Western blotting, while PC2 levels remained unaffected. Most likely due to the continued presence of PC2, pituitary and brain levels of α-MSH were not impaired. Analysis of intestinal cell types indicated a modest reduction of enteroendocrine cells in G209R homozygotes. We suggest that the G209R Pcsk1 mouse model recapitulates many of the dramatic neonatal deficiencies of human patients with this homozygous mutation.
Collapse
Affiliation(s)
- Manita Shakya
- Department of Anatomy & Neurobiology, University of Maryland School of
Medicine, Baltimore, MD, USA
| | - Surbhi
- Department Molecular & Integrative Physiology, University of
Michigan, Ann Arbor, MI, USA
| | - Nicolle K Martin
- Department of Pediatrics, Division of Gastroenterology and Nutrition, Mattel
Children’s Hospital and the David Geffen School of Medicine, University of California Los
Angeles, Los Angeles, CA, USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of
Michigan, Ann Arbor, MI, USA
| | - Martin G Martin
- Department of Pediatrics, Division of Gastroenterology and Nutrition, Mattel
Children’s Hospital and the David Geffen School of Medicine, University of California Los
Angeles, Los Angeles, CA, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of
Michigan, Ann Arbor, MI, USA
| | - Malcolm J Low
- Department Molecular & Integrative Physiology, University of
Michigan, Ann Arbor, MI, USA
| | - Iris Lindberg
- Department of Anatomy & Neurobiology, University of Maryland School of
Medicine, Baltimore, MD, USA
- Correspondence: Iris Lindberg, PhD, Department of Anatomy and Neurobiology, University of Maryland
School of Medicine, 20 Penn St, HSF2, S218, Baltimore, MD 21201, USA.
| |
Collapse
|
10
|
Ni Y, Chen X, Sun Y, Pan J, Tang C, Yuan T. Modulation of PC1/3 activity by a rare double-site homozygous mutation. Front Pediatr 2022; 10:1026707. [PMID: 36389395 PMCID: PMC9659753 DOI: 10.3389/fped.2022.1026707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/10/2022] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVES Preprotein convertase 1/3 deficiency is a rare autosomal recessive disorder in which patients present with malabsorptive diarrhea and a series of symptoms of endocrine disorders such as polydipsia, reactive hypoglycemia, growth hormone deficiency, hypothyroidism, adrenal insufficiency, and early onset obesity. In its essence, pituitary hormone deficiency is caused by insufficient cleavage of pituitary prohormones. Here, we describe a female child with a rare double-site homozygous mutation in PCSK1 (Proprotein convertase subtilisin/kexin-type 1) gene, and thereby intend to investigate the relationship between these novel mutation sites and changes in protein synthesis and function. METHODS We tested this patient's blood and urine fecal indicators of infection, blood electrolytes, and relevant endocrine hormone levels in the laboratory. Next Generation Sequencing was applied to screen the patient's DNA. Western Blot was performed to evaluate the mutant protein's expression. The enzymatic activity was measured as the rate of cleavage of a synthetic fluorogenic substrate in a specific solution. RESULTS We found that this patient presented shortly after birth with uncorrectable diarrhea and symptoms of metabolic acidosis with hypothyroidism. Next Generation Sequencing revealed that a rare double-site homozygous missense mutation, c.763G > A (p.G255R) and c.758C > T (p.S253L), were detected in exon 7 of PCSK1 (Proprotein convertase subtilisin/kexin-type 1) gene on chromosome 5 of the patient. Western blotting revealed that there was no significant decrease in protein synthesis levels in the mutant phenotype compared to the wild type. Compared with WT type, the proteins expressed by the mutations showed a significant decrease in the enzyme activity towards the fluorescent substrates. However, neither the single site mutation p.S253L or p.G255R, nor the double-site mutation of both, all showed no significant differences from each other. CONCLUSIONS These two missense mutations have not been reported before, and it is even rarer to find homozygous variation of two sites in one patient. This study identifies two novel mutations for the first time and further investigates the changes in protein synthesis and enzyme activity, providing a new pathway to continue to explore the pathogenesis of diseases associated with the function of PC1/3.
Collapse
Affiliation(s)
- Yanyan Ni
- Department of Neonatology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Xiangxiang Chen
- Department of Neonatology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Yi Sun
- Department of Neonatology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Jiarong Pan
- Department of Neonatology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Chao Tang
- National Clinical Research Center for Child Health of the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Tianming Yuan
- Department of Neonatology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| |
Collapse
|
11
|
Seidah NG. The PCSK9 discovery, an inactive protease with varied functions in hypercholesterolemia, viral infections, and cancer. J Lipid Res 2021; 62:100130. [PMID: 34606887 PMCID: PMC8551645 DOI: 10.1016/j.jlr.2021.100130] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/19/2021] [Accepted: 08/21/2021] [Indexed: 01/06/2023] Open
Abstract
In 2003, the sequences of mammalian proprotein convertase subtilisin/kexin type 9 (PCSK9) were reported. Radiolabeling pulse-chase analyses demonstrated that PCSK9 was synthesized as a precursor (proPCSK9) that undergoes autocatalytic cleavage in the endoplasmic reticulum into PCSK9, which is then secreted as an inactive enzyme in complex with its inhibitory prodomain. Its high mRNA expression in liver hepatocytes and its gene localization on chromosome 1p32, a third locus associated with familial hypercholesterolemia, other than LDLR or APOB, led us to identify three patient families expressing the PCSK9 variants S127R or F216L. Although Pcsk9 and Ldlr were downregulated in mice that were fed a cholesterol-rich diet, PCSK9 overexpression led to the degradation of the LDLR. This led to the demonstration that gain-of-function and loss-of-function variations in PCSK9 modulate its bioactivity, whereby PCSK9 binds the LDLR in a nonenzymatic fashion to induce its degradation in endosomes/lysosomes. PCSK9 was also shown to play major roles in targeting other receptors for degradation, thereby regulating various processes, including hypercholesterolemia and associated atherosclerosis, vascular inflammation, viral infections, and immune checkpoint regulation in cancer. Injectable PCSK9 monoclonal antibody or siRNA is currently used in clinics worldwide to treat hypercholesterolemia and could be combined with current therapies in cancer/metastasis. In this review, we present the critical information that led to the discovery of PCSK9 and its implication in LDL-C metabolism. We further analyze the underlying functional mechanism(s) in the regulation of LDL-C, as well as the evolving novel roles of PCSK9 in both health and disease states.
Collapse
Affiliation(s)
- Nabil G Seidah
- Laboratory of Biochemical Neuroendocrinology, Montreal Clinical Research Institute (IRCM, affiliated to the University of Montreal), 110 Pine Ave West, Montreal, QC, H2W 1R7, Canada.
| |
Collapse
|
12
|
Courbage S, Poitou C, Le Beyec-Le Bihan J, Karsenty A, Lemale J, Pelloux V, Lacorte JM, Carel JC, Lecomte N, Storey C, De Filippo G, Coupaye M, Oppert JM, Tounian P, Clément K, Dubern B. Implication of Heterozygous Variants in Genes of the Leptin-Melanocortin Pathway in Severe Obesity. J Clin Endocrinol Metab 2021; 106:2991-3006. [PMID: 34097736 DOI: 10.1210/clinem/dgab404] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Unlike homozygous variants, the implication of heterozygous variants on the leptin-melanocortin pathway in severe obesity has not been established. OBJECTIVE To describe the frequency, the phenotype, and the genotype-phenotype relationship for heterozygous variants in LEP, LEPR, POMC, and PCSK1 in severe obesity. METHODS In this retrospective study, genotyping was performed on at least 1 of the LEP, LEPR, POMC, and PCSK1 genes in 1486 probands with severe obesity (600 children, 886 adults). The phenotype was collected in 60 subjects with heterozygous variants and 16 with homozygous variants. We analyzed variant frequency, body mass index (BMI), age of obesity onset, food impulsivity, and endocrine abnormalities. RESULTS The frequency of subjects with homozygous variants was 1.7% (n = 26), and 6.7% (n = 100) with heterozygous variants. Adults with homozygous variants had a higher BMI (66 vs 53 kg/m2, P = .015), an earlier onset of obesity (0.4 vs 5.4 years, P < .001), more often food impulsivity (83% vs 42%, P = .04), and endocrine abnormalities (75% vs 26%, P < .01). The BMI was higher for subjects with high-impact heterozygous variants (61 vs 50 kg/m², P = .045) and those with a second heterozygous variant on the pathway (65 vs 49 kg/m², P < .01). In children, no significant differences were found for the age of obesity onset and BMI. CONCLUSION Heterozygous variants in LEP, LEPR, POMC, and PCSK1 are frequent in severe obesity and sometimes associated with a phenotype close to that of homozygotes. These data suggest a systematic search for variants in severe early-onset obesity, to discuss therapy that targets this key pathway.
Collapse
Affiliation(s)
- Sophie Courbage
- Assistance Publique-Hôpitaux de Paris (AP-HP), Reference Centre for Rare Diseases (PRADORT, Prader-Willi Syndrome and other Rare Forms of Obesity with Eating Behavior Disorders), Pediatric Nutrition and Gastroenterology Department, Armand-Trousseau Hospital, Sorbonne University, Paris, France
- Sorbonne Université, INSERM, Nutrition and Obesities; Systemic Approaches (NutriOmics) Research Unit, Paris, France
| | - Christine Poitou
- Assistance Publique-Hôpitaux de Paris (AP-HP), Reference Centre for Rare Diseases (PRADORT, Prader-Willi Syndrome and other Rare Forms of Obesity with Eating Behavior Disorders), Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France
- Sorbonne Université, INSERM, Nutrition and Obesities; Systemic Approaches (NutriOmics) Research Unit, Paris, France
| | - Johanne Le Beyec-Le Bihan
- Assistance Publique-Hôpitaux de Paris (AP-HP), Endocrine and Oncological Biochemistry Department, Pitié-Salpêtrière Hospital, Sorbonne University, Paris, France
| | - Alexandra Karsenty
- Assistance Publique-Hôpitaux de Paris (AP-HP), Reference Centre for Rare Diseases (PRADORT, Prader-Willi Syndrome and other Rare Forms of Obesity with Eating Behavior Disorders), Pediatric Nutrition and Gastroenterology Department, Armand-Trousseau Hospital, Sorbonne University, Paris, France
| | - Julie Lemale
- Assistance Publique-Hôpitaux de Paris (AP-HP), Reference Centre for Rare Diseases (PRADORT, Prader-Willi Syndrome and other Rare Forms of Obesity with Eating Behavior Disorders), Pediatric Nutrition and Gastroenterology Department, Armand-Trousseau Hospital, Sorbonne University, Paris, France
| | - Véronique Pelloux
- Sorbonne Université, INSERM, Nutrition and Obesities; Systemic Approaches (NutriOmics) Research Unit, Paris, France
| | - Jean-Marc Lacorte
- Assistance Publique-Hôpitaux de Paris (AP-HP), Endocrine and Oncological Biochemistry Department, Pitié-Salpêtrière Hospital, Sorbonne University, Paris, France
| | - Jean-Claude Carel
- Université de Paris, F-75019, Paris, France; AP-HP.Nord Université de Paris. Hôpital Universitaire Robert-Debré, Service d'Endocrinologie Diabétologie Pédiatrique F-75019, Paris, France
| | - Nathalie Lecomte
- Université de Paris, F-75019, Paris, France; AP-HP.Nord Université de Paris. Hôpital Universitaire Robert-Debré, Service d'Endocrinologie Diabétologie Pédiatrique F-75019, Paris, France
| | - Caroline Storey
- Université de Paris, F-75019, Paris, France; AP-HP.Nord Université de Paris. Hôpital Universitaire Robert-Debré, Service d'Endocrinologie Diabétologie Pédiatrique F-75019, Paris, France
| | - Gianpaolo De Filippo
- Université de Paris, F-75019, Paris, France; AP-HP.Nord Université de Paris. Hôpital Universitaire Robert-Debré, Service d'Endocrinologie Diabétologie Pédiatrique F-75019, Paris, France
- Assistance Publique-Hôpitaux de Paris (AP-HP), Bicêtre Hospital, Medicine for Adolescents Department, Le Kremlin-Bicêtre, France
| | - Muriel Coupaye
- Assistance Publique-Hôpitaux de Paris (AP-HP), Reference Centre for Rare Diseases (PRADORT, Prader-Willi Syndrome and other Rare Forms of Obesity with Eating Behavior Disorders), Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France
- Assistance Publique-Hôpitaux de Paris (AP-HP), Explorations Fonctionnelles Department, Louis-Mourier Hospital, Centre Intégré Nord Francilien de l'Obésité (CINFO) and Université de Paris, Centre de Recherche sur l'Inflammation, Inserm UMRS 1149, Paris, France
| | - Jean-Michel Oppert
- Assistance Publique-Hôpitaux de Paris (AP-HP), Reference Centre for Rare Diseases (PRADORT, Prader-Willi Syndrome and other Rare Forms of Obesity with Eating Behavior Disorders), Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France
| | - Patrick Tounian
- Assistance Publique-Hôpitaux de Paris (AP-HP), Reference Centre for Rare Diseases (PRADORT, Prader-Willi Syndrome and other Rare Forms of Obesity with Eating Behavior Disorders), Pediatric Nutrition and Gastroenterology Department, Armand-Trousseau Hospital, Sorbonne University, Paris, France
- Sorbonne Université, INSERM, Nutrition and Obesities; Systemic Approaches (NutriOmics) Research Unit, Paris, France
| | - Karine Clément
- Assistance Publique-Hôpitaux de Paris (AP-HP), Reference Centre for Rare Diseases (PRADORT, Prader-Willi Syndrome and other Rare Forms of Obesity with Eating Behavior Disorders), Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France
- Sorbonne Université, INSERM, Nutrition and Obesities; Systemic Approaches (NutriOmics) Research Unit, Paris, France
| | - Béatrice Dubern
- Assistance Publique-Hôpitaux de Paris (AP-HP), Reference Centre for Rare Diseases (PRADORT, Prader-Willi Syndrome and other Rare Forms of Obesity with Eating Behavior Disorders), Pediatric Nutrition and Gastroenterology Department, Armand-Trousseau Hospital, Sorbonne University, Paris, France
- Sorbonne Université, INSERM, Nutrition and Obesities; Systemic Approaches (NutriOmics) Research Unit, Paris, France
| |
Collapse
|
13
|
Powell DR, Revelli JP, Doree DD, DaCosta CM, Desai U, Shadoan MK, Rodriguez L, Mullens M, Yang QM, Ding ZM, Kirkpatrick LL, Vogel P, Zambrowicz B, Sands AT, Platt KA, Hansen GM, Brommage R. High-Throughput Screening of Mouse Gene Knockouts Identifies Established and Novel High Body Fat Phenotypes. Diabetes Metab Syndr Obes 2021; 14:3753-3785. [PMID: 34483672 PMCID: PMC8409770 DOI: 10.2147/dmso.s322083] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/04/2021] [Indexed: 01/05/2023] Open
Abstract
PURPOSE Obesity is a major public health problem. Understanding which genes contribute to obesity may better predict individual risk and allow development of new therapies. Because obesity of a mouse gene knockout (KO) line predicts an association of the orthologous human gene with obesity, we reviewed data from the Lexicon Genome5000TM high throughput phenotypic screen (HTS) of mouse gene KOs to identify KO lines with high body fat. MATERIALS AND METHODS KO lines were generated using homologous recombination or gene trapping technologies. HTS body composition analyses were performed on adult wild-type and homozygous KO littermate mice from 3758 druggable mouse genes having a human ortholog. Body composition was measured by either DXA or QMR on chow-fed cohorts from all 3758 KO lines and was measured by QMR on independent high fat diet-fed cohorts from 2488 of these KO lines. Where possible, comparisons were made to HTS data from the International Mouse Phenotyping Consortium (IMPC). RESULTS Body fat data are presented for 75 KO lines. Of 46 KO lines where independent external published and/or IMPC KO lines are reported as obese, 43 had increased body fat. For the remaining 29 novel high body fat KO lines, Ksr2 and G2e3 are supported by data from additional independent KO cohorts, 6 (Asnsd1, Srpk2, Dpp8, Cxxc4, Tenm3 and Kiss1) are supported by data from additional internal cohorts, and the remaining 21 including Tle4, Ak5, Ntm, Tusc3, Ankk1, Mfap3l, Prok2 and Prokr2 were studied with HTS cohorts only. CONCLUSION These data support the finding of high body fat in 43 independent external published and/or IMPC KO lines. A novel obese phenotype was identified in 29 additional KO lines, with 27 still lacking the external confirmation now provided for Ksr2 and G2e3 KO mice. Undoubtedly, many mammalian obesity genes remain to be identified and characterized.
Collapse
Affiliation(s)
- David R Powell
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Jean-Pierre Revelli
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Deon D Doree
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Christopher M DaCosta
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Urvi Desai
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Melanie K Shadoan
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Lawrence Rodriguez
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Michael Mullens
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Qi M Yang
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Zhi-Ming Ding
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Laura L Kirkpatrick
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Peter Vogel
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Brian Zambrowicz
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Arthur T Sands
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Kenneth A Platt
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Gwenn M Hansen
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Robert Brommage
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| |
Collapse
|
14
|
Koerber-Rosso I, Brandt S, von Schnurbein J, Fischer-Posovszky P, Hoegel J, Rabenstein H, Siebert R, Wabitsch M. A fresh look to the phenotype in mono-allelic likely pathogenic variants of the leptin and the leptin receptor gene. Mol Cell Pediatr 2021; 8:10. [PMID: 34448070 PMCID: PMC8390564 DOI: 10.1186/s40348-021-00119-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/19/2021] [Indexed: 12/16/2022] Open
Abstract
Leptin (LEP) and leptin receptor (LEPR) play a major role in energy homeostasis, metabolism, and reproductive function. While effects of biallelic likely pathogenic variants (-/-) on the phenotype are well characterized, effects of mono-allelic likely pathogenic variants (wt/-) in the LEP and LEPR gene on the phenotype compared to wild-type homozygosity (wt/wt) have not been systematically investigated. We identified in our systematic review 44 animal studies (15 on Lep, 29 on Lepr) and 39 studies in humans reporting on 130 mono-allelic likely pathogenic variant carriers with 20 distinct LEP variants and 108 heterozygous mono-allelic likely pathogenic variant carriers with 35 distinct LEPR variants. We found indications for a higher weight status in carriers of mono-allelic likely pathogenic variant in the leptin and in the leptin receptor gene compared to wt/wt, in both animal and human studies. In addition, animal studies showed higher body fat percentage in Lep and Lepr wt/- vs wt/wt. Animal studies provided indications for lower leptin levels in Lep wt/- vs. wt/wt and indications for higher leptin levels in Lepr wt/- vs wt/wt. Data on leptin levels in human studies was limited. Evidence for an impaired metabolism in mono-allelic likely pathogenic variants of the leptin and in leptin receptor gene was not conclusive (animal and human studies). Mono-allelic likely pathogenic variants in the leptin and in leptin receptor gene have phenotypic effects disposing to increased body weight and fat accumulation.
Collapse
Affiliation(s)
- Ingrid Koerber-Rosso
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Stephanie Brandt
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Julia von Schnurbein
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Pamela Fischer-Posovszky
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Josef Hoegel
- Institute of Human Genetics, University of Ulm, University Medical Center Ulm, Ulm, Germany
| | - Hannah Rabenstein
- Institute of Human Genetics, University of Ulm, University Medical Center Ulm, Ulm, Germany
| | - Reiner Siebert
- Institute of Human Genetics, University of Ulm, University Medical Center Ulm, Ulm, Germany
| | - Martin Wabitsch
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany.
| |
Collapse
|
15
|
Ramzy A, Kieffer TJ. Altered islet prohormone processing: A cause or consequence of diabetes? Physiol Rev 2021; 102:155-208. [PMID: 34280055 DOI: 10.1152/physrev.00008.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Peptide hormones are first produced as larger precursor prohormones that require endoproteolytic cleavage to liberate the mature hormones. A structurally conserved but functionally distinct family of nine prohormone convertase enzymes (PCs) are responsible for cleavage of protein precursors of which PC1/3 and PC2 are known to be exclusive to neuroendocrine cells and responsible for prohormone cleavage. Differential expression of PCs within tissues define prohormone processing; whereas glucagon is the major product liberated from proglucagon via PC2 in pancreatic α-cells, proglucagon is preferentially processed by PC1/3 in intestinal L cells to produce glucagon-like peptides 1 and 2 (GLP-1, GLP-2). Beyond our understanding of processing of islet prohormones in healthy islets, there is convincing evidence that proinsulin, proIAPP, and proglucagon processing is altered during prediabetes and diabetes. There is predictive value of elevated circulating proinsulin or proinsulin : C-peptide ratio for progression to type 2 diabetes and elevated proinsulin or proinsulin : C-peptide is predictive for development of type 1 diabetes in at risk groups. After onset of diabetes, patients have elevated circulating proinsulin and proIAPP and proinsulin may be an autoantigen in type 1 diabetes. Further, preclinical studies reveal that α-cells have altered proglucagon processing during diabetes leading to increased GLP-1 production. We conclude that despite strong associative data, current evidence is inconclusive on the potential causal role of impaired prohormone processing in diabetes, and suggest that future work should focus on resolving the question of whether altered prohormone processing is a causal driver or merely a consequence of diabetes pathology.
Collapse
Affiliation(s)
- Adam Ramzy
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Timothy J Kieffer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.,Department of Surgery, University of British Columbia, Vancouver, BC, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
16
|
Abstract
The kexin-like proprotein convertases perform the initial proteolytic cleavages that ultimately generate a variety of different mature peptide and proteins, ranging from brain neuropeptides to endocrine peptide hormones, to structural proteins, among others. In this review, we present a general introduction to proprotein convertase structure and biochemistry, followed by a comprehensive discussion of each member of the kexin-like subfamily of proprotein convertases. We summarize current knowledge of human proprotein convertase insufficiency syndromes, including genome-wide analyses of convertase polymorphisms, and compare these to convertase null and mutant mouse models. These mouse models have illuminated our understanding of the roles specific convertases play in human disease and have led to the identification of convertase-specific substrates; for example, the identification of procorin as a specific PACE4 substrate in the heart. We also discuss the limitations of mouse null models in interpreting human disease, such as differential precursor cleavage due to species-specific sequence differences, and the challenges presented by functional redundancy among convertases in attempting to assign specific cleavages and/or physiological roles. However, in most cases, knockout mouse models have added substantively both to our knowledge of diseases caused by human proprotein convertase insufficiency and to our appreciation of their normal physiological roles, as clearly seen in the case of the furin, proprotein convertase 1/3, and proprotein convertase 5/6 mouse models. The creation of more sophisticated mouse models with tissue- or temporally-restricted expression of specific convertases will improve our understanding of human proprotein convertase insufficiency and potentially provide support for the emerging concept of therapeutic inhibition of convertases.
Collapse
Affiliation(s)
- Manita Shakya
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| |
Collapse
|
17
|
Novel Homozygous Inactivating Mutation in the PCSK1 Gene in an Infant with Congenital Malabsorptive Diarrhea. Genes (Basel) 2021; 12:genes12050710. [PMID: 34068683 PMCID: PMC8151971 DOI: 10.3390/genes12050710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/02/2021] [Accepted: 05/07/2021] [Indexed: 01/03/2023] Open
Abstract
Proprotein convertase 1/3 (PC1/3), encoded by the PCSK1 gene, is expressed in neuronal and (entero)endocrine cell types, where it cleaves and hence activates a number of protein precursors that play a key role in energy homeostasis. Loss-of-function mutations in PCSK1 cause a recessive complex endocrinopathy characterized by malabsorptive diarrhea and early-onset obesity. Despite the fact that neonatal malabsorptive diarrhea is observed in all patients, it has remained understudied. The aim of this study was to investigate the enteroendocrine pathologies in a male patient with congenital PCSK1 deficiency carrying the novel homozygous c.1034A>C (p.E345A) mutation. This patient developed malabsorptive diarrhea and metabolic acidosis within the first week of life, but rapid weight gain was observed after total parenteral nutrition, and he displayed high proinsulin levels and low adrenocorticotropin. In vitro analysis showed that the p.E345A mutation in PC1/3 resulted in a (near) normal autocatalytic proPC1/3 processing and only partially impaired PC1/3 secretion, but the processing of a substrate in trans was completely blocked. Immunohistochemical staining did not reveal changes in the proGIP/GIP and proglucagon/GLP-1 ratio in colonic tissue. Hence, we report a novel PCSK1 deficient patient who, despite neonatal malabsorptive diarrhea, showed a normal morphology in the small intestine.
Collapse
|
18
|
Ahmed ABM, Alsaleem BMR. Enteroendocrine Dysfunction in Two Saudi Sisters. Case Rep Gastroenterol 2021; 15:290-295. [PMID: 33790717 PMCID: PMC7989775 DOI: 10.1159/000511761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/18/2020] [Indexed: 12/29/2022] Open
Abstract
Proprotein convertase (PC) deficiency is a rare autosomal recessive disorder caused by mutations in proprotein convertase subtilisin/kexin type 1 (PCSK1). It is characterized by severe malabsorptive early-onset diarrhea, obesity, and systemic endocrinopathies. Only few cases have been reported in the literature; we have add two female sisters with some difference in clinical progress. Herein, we describe two sisters with congenital osmotic diarrhea diagnosed with PC1/3 deficiency, causing malabsorptive diarrhea and enteroendocrine dysfunction, who presented with chronic enteropathy with hypernatremia but with different expressivity. PC1/3 deficiency presents with symptoms and signs that mimic glucose-galactose malabsorption. Because of the clinical paucity and heterogeneity of congenital enteropathies, whole-exome sequencing may be of great help towards early diagnosis and effective treatment.
Collapse
Affiliation(s)
- Amna Basheer M Ahmed
- Department of Pediatric Gastroenterology/Hepatology, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Badr M Rasheed Alsaleem
- Department of Pediatric Gastroenterology/Hepatology, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| |
Collapse
|
19
|
Brouwers B, Coppola I, Vints K, Dislich B, Jouvet N, Van Lommel L, Segers C, Gounko NV, Thorrez L, Schuit F, Lichtenthaler SF, Estall JL, Declercq J, Ramos-Molina B, Creemers JWM. Loss of Furin in β-Cells Induces an mTORC1-ATF4 Anabolic Pathway That Leads to β-Cell Dysfunction. Diabetes 2021; 70:492-503. [PMID: 33277337 DOI: 10.2337/db20-0474] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 11/19/2020] [Indexed: 11/13/2022]
Abstract
FURIN is a proprotein convertase (PC) responsible for proteolytic activation of a wide array of precursor proteins within the secretory pathway. It maps to the PRC1 locus, a type 2 diabetes susceptibility locus, but its specific role in pancreatic β-cells is largely unknown. The aim of this study was to determine the role of FURIN in glucose homeostasis. We show that FURIN is highly expressed in human islets, whereas PCs that potentially could provide redundancy are expressed at considerably lower levels. β-cell-specific Furin knockout (βFurKO) mice are glucose intolerant as a result of smaller islets with lower insulin content and abnormal dense-core secretory granule morphology. mRNA expression analysis and differential proteomics on βFurKO islets revealed activation of activating transcription factor 4 (ATF4), which was mediated by mammalian target of rapamycin C1 (mTORC1). βFurKO cells show impaired cleavage or shedding of vacuolar-type ATPase (V-ATPase) subunits Ac45 and prorenin receptor, respectively, and impaired lysosomal acidification. Blocking V-ATPase pharmacologically in β-cells increased mTORC1 activity, suggesting involvement of the V-ATPase proton pump in the phenotype. Taken together, these results suggest a model of mTORC1-ATF4 hyperactivation and impaired lysosomal acidification in β-cells lacking Furin, causing β-cell dysfunction.
Collapse
Affiliation(s)
- Bas Brouwers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
- Metabolic Research Laboratories, Wellcome Trust Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Ilaria Coppola
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Katlijn Vints
- Electron Microscopy Platform and Vlaams Instituut voor Biotechnologie (VIB) Bioimaging Core, VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- Leuven Brain Institute, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Bastian Dislich
- German Center for Neurodegenerative Diseases, Munich, Germany
- Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Nathalie Jouvet
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada
| | - Leentje Van Lommel
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Charlotte Segers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
- Interdisciplinary Biosciences Group, Belgian Nuclear Research Centre, SCK CEN, Mol, Belgium
- Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Natalia V Gounko
- Electron Microscopy Platform and Vlaams Instituut voor Biotechnologie (VIB) Bioimaging Core, VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- Leuven Brain Institute, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Lieven Thorrez
- Department of Development and Regeneration, Campus Kulak, KU Leuven, Kortrijk, Belgium
| | - Frans Schuit
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases, Munich, Germany
- Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Jennifer L Estall
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada
| | - Jeroen Declercq
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
- German Center for Neurodegenerative Diseases, Munich, Germany
| | - Bruno Ramos-Molina
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
- Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain
| | - John W M Creemers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| |
Collapse
|
20
|
Rare genetic forms of obesity: From gene to therapy. Physiol Behav 2020; 227:113134. [DOI: 10.1016/j.physbeh.2020.113134] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 07/15/2020] [Accepted: 07/21/2020] [Indexed: 01/05/2023]
|
21
|
Signatures of natural selection and ethnic-specific prevalence of NPC1 pathogenic mutations contributing to obesity and Niemann-Pick disease type C1. Sci Rep 2020; 10:18787. [PMID: 33139814 PMCID: PMC7608643 DOI: 10.1038/s41598-020-75919-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/21/2020] [Indexed: 11/13/2022] Open
Abstract
While homozygous pathogenic mutations in the NPC1 gene cause Niemann-Pick type C1 disease, heterozygous mutations cause highly-penetrant obesity. We aimed to investigate the prevalence of NPC1 mutations and their signatures of natural selection in 122,678 exome sequenced participants from six ethnic groups in the Genome Aggregation Database. Pathogenic missense coding mutations were identified by in silico tools and the ClinVar database. Signatures of natural selection were assessed by the probability of NPC1 being loss-of-function mutation intolerant and Z-scores of observed/expected synonymous and non-synonymous mutation ratios. There was no evidence of negative selection observed for synonymous, non-synonymous and loss-of-function mutations. However, there were significant ethnic differences in the prevalence of heterozygous pathogenic NPC1 mutations ranging from 0.56% in Ashkenazi Jewish to 3.26% in African/African Americans (5.8-fold difference). Four homozygous carriers of pathogenic NPC1 mutations were also identified, belonging to the South Asian population. In conclusion, NPC1 mutations are consistent with a model of balanced selection, where heterozygotes and homozygotes have higher and lower reproductive fitness, respectively. Therefore, NPC1 heterozygous mutations may account for a substantial and ethnic-dependent percentage of obesity in the general population, while NPC1 homozygous mutations may be frequent in the South Asian populations and warrants more investigation.
Collapse
|
22
|
Flores-Dorantes MT, Díaz-López YE, Gutiérrez-Aguilar R. Environment and Gene Association With Obesity and Their Impact on Neurodegenerative and Neurodevelopmental Diseases. Front Neurosci 2020; 14:863. [PMID: 32982666 PMCID: PMC7483585 DOI: 10.3389/fnins.2020.00863] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
Obesity is a multifactorial disease in which environmental conditions and several genes play an important role in the development of this disease. Obesity is associated with neurodegenerative diseases (Alzheimer, Parkinson, and Huntington diseases) and with neurodevelopmental diseases (autism disorder, schizophrenia, and fragile X syndrome). Some of the environmental conditions that lead to obesity are physical activity, alcohol consumption, socioeconomic status, parent feeding behavior, and diet. Interestingly, some of these environmental conditions are shared with neurodegenerative and neurodevelopmental diseases. Obesity impairs neurodevelopment abilities as memory and fine-motor skills. Moreover, maternal obesity affects the cognitive function and mental health of the offspring. The common biological mechanisms involved in obesity and neurodegenerative/neurodevelopmental diseases are insulin resistance, pro-inflammatory cytokines, and oxidative damage, among others, leading to impaired brain development or cell death. Obesogenic environmental conditions are not the only factors that influence neurodegenerative and neurodevelopmental diseases. In fact, several genes implicated in the leptin-melanocortin pathway (LEP, LEPR, POMC, BDNF, MC4R, PCSK1, SIM1, BDNF, TrkB, etc.) are associated with obesity and neurodegenerative and neurodevelopmental diseases. Moreover, in the last decades, the discovery of new genes associated with obesity (FTO, NRXN3, NPC1, NEGR1, MTCH2, GNPDA2, among others) and with neurodegenerative or neurodevelopmental diseases (APOE, CD38, SIRT1, TNFα, PAI-1, TREM2, SYT4, FMR1, TET3, among others) had opened new pathways to comprehend the common mechanisms involved in these diseases. In conclusion, the obesogenic environmental conditions, the genes, and the interaction gene-environment would lead to a better understanding of the etiology of these diseases.
Collapse
Affiliation(s)
- María Teresa Flores-Dorantes
- Laboratorio de Biología Molecular y Farmacogenómica, Centro de Investigación de Ciencia y Tecnología Aplicada de Tabasco, División Académica de Ciencias Básicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Mexico
| | - Yael Efren Díaz-López
- Laboratorio de Enfermedades Metabólicas: Obesidad y Diabetes, Hospital Infantil de México “Federico Gómez,”Mexico City, Mexico
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Ruth Gutiérrez-Aguilar
- Laboratorio de Enfermedades Metabólicas: Obesidad y Diabetes, Hospital Infantil de México “Federico Gómez,”Mexico City, Mexico
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| |
Collapse
|
23
|
Kleinendorst L, Abawi O, van der Voorn B, Jongejan MHTM, Brandsma AE, Visser JA, van Rossum EFC, van der Zwaag B, Alders M, Boon EMJ, van Haelst MM, van den Akker ELT. Identifying underlying medical causes of pediatric obesity: Results of a systematic diagnostic approach in a pediatric obesity center. PLoS One 2020; 15:e0232990. [PMID: 32384097 PMCID: PMC7209105 DOI: 10.1371/journal.pone.0232990] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/24/2020] [Indexed: 12/12/2022] Open
Abstract
Background Underlying medical causes of obesity (endocrine disorders, genetic obesity disorders, cerebral or medication-induced obesities) are thought to be rare. Even in specialized pediatric endocrinology clinics, low diagnostic yield is reported, but evidence is limited. Identifying these causes is vital for patient-tailored treatment. Objectives To present the results of a systematic diagnostic workup in children and adolescents referred to a specialized pediatric obesity center. Methods This is a prospective observational study. Prevalence of underlying medical causes was determined after a multidisciplinary, systematic diagnostic workup including growth charts analysis, extensive biochemical and hormonal assessment and genetic testing in all patients. Results The diagnostic workup was completed in n = 282 patients. Median age was 10.8 years (IQR 7.7–14.1); median BMI +3.7SDS (IQR +3.3-+4.3). In 54 (19%) patients, a singular underlying medical cause was identified: in 37 patients genetic obesity, in 8 patients cerebral and in 9 patients medication-induced obesities. In total, thirteen different genetic obesity disorders were diagnosed. Obesity onset <5 years (p = 0.04) and hyperphagia (p = 0.001) were indicators of underlying genetic causes, but only in patients without intellectual disability (ID). Patients with genetic obesity with ID more often had a history of neonatal feeding problems (p = 0.003) and short stature (p = 0.005). BMI-SDS was not higher in patients with genetic obesity disorders (p = 0.52). Patients with cerebral and medication-induced obesities had lower height-SDS than the rest of the cohort. Conclusions To our knowledge, this is the first study to report the results of a systematic diagnostic workup aimed at identifying endocrine, genetic, cerebral or medication-induced causes of pediatric obesity. We found that a variety of singular underlying causes were identified in 19% of the patients with severe childhood obesity. Because of this heterogeneity, an extensive diagnostic approach is needed to establish the underlying medical causes and to facilitate disease-specific, patient-tailored treatment.
Collapse
Affiliation(s)
- Lotte Kleinendorst
- Obesity Center CGG, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Ozair Abawi
- Obesity Center CGG, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Division of Endocrinology, Department of Pediatrics, Erasmus MC-Sophia Children’s Hospital, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Bibian van der Voorn
- Obesity Center CGG, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Division of Endocrinology, Department of Pediatrics, Erasmus MC-Sophia Children’s Hospital, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Division of Endocrinology, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Mieke H. T. M. Jongejan
- Department of Pediatrics, Obesity Center CGG, Franciscus Gasthuis, Rotterdam, The Netherlands
| | - Annelies E. Brandsma
- Department of Pediatrics, Obesity Center CGG, Maasstad Ziekenhuis, Rotterdam, The Netherlands
| | - Jenny A. Visser
- Obesity Center CGG, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Division of Endocrinology, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Elisabeth F. C. van Rossum
- Obesity Center CGG, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Division of Endocrinology, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Bert van der Zwaag
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mariëlle Alders
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Elles M. J. Boon
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Mieke M. van Haelst
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erica L. T. van den Akker
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- * E-mail:
| |
Collapse
|
24
|
Molecular pathway analysis associates alterations in obesity-related genes and antipsychotic-induced weight gain. Acta Neuropsychiatr 2020; 32:72-83. [PMID: 31619305 DOI: 10.1017/neu.2019.41] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Antipsychotics often induce excessive weight gain. We hypothesised that individuals with genetic variations related to known obesity-risk genes have an increased risk of excessive antipsychotic-induced weight gain (AIWG). This hypothesis was tested in a subset of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) trial data set. METHODS The CATIE trial compared effects and side effects of five different antipsychotics through an 18-month period. Based on the maximum weight gain recorded, excessive weight gain was defined as >7% weight gain. Cytoscape and GeneMANIA were instrumental in composing a molecular pathway from eight selected genes linked to obesity. Genetic information on a total of 495.172 single-nucleotide polymorphisms (SNPs) were available from 765 (556 males) individuals. Enrichment test was conducted through ReactomePA and Bioconductor. A permutation test was performed, testing the generated pathway against 105 permutated pathways (p ≤ 0.05). In addition, a standard genome-wide association study (GWAS) analysis was performed. RESULT GWAS analysis did not detect significant differences related to excessive weight gain. The pathway generated contained 28 genes. A total of 2067 SNPs were significantly expressed (p < 0.01) within this pathway when comparing excessive weight gainers to the rest of the sample. Affected genes including PPARG and PCSK1 were not previously related to treatment-induced weight gain. CONCLUSIONS The molecular pathway composed from high-risk obesity genes was shown to overlap with genetics of patients who gained >7% weight gain during the CATIE trial. This suggests that genes related to obesity compose a pathway of increased risk of excessive AIWG. Further independent analyses are warranted that may confirm or clarify the possible reasoning behind.
Collapse
|
25
|
Muhsin NIA, Bentley L, Bai Y, Goldsworthy M, Cox RD. A novel mutation in the mouse Pcsk1 gene showing obesity and diabetes. Mamm Genome 2020; 31:17-29. [PMID: 31974728 PMCID: PMC7060156 DOI: 10.1007/s00335-020-09826-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/07/2020] [Indexed: 12/14/2022]
Abstract
The proprotein convertase subtilisin/Kexin type 1 (PCSK1/PC1) protein processes inactive pro-hormone precursors into biologically active hormones in a number of neuroendocrine and endocrine cell types. Patients with recessive mutations in PCSK1 exhibit a complex spectrum of traits including obesity, diarrhoea and endocrine disorders. We describe here a new mouse model with a point mutation in the Pcsk1 gene that exhibits obesity, hyperphagia, transient diarrhoea and hyperproinsulinaemia, phenotypes consistent with human patient traits. The mutation results in a pV96L amino acid substitution and changes the first nucleotide of mouse exon 3 leading to skipping of that exon and in homozygotes very little full-length transcript. Overexpression of the exon 3 deleted protein or the 96L protein results in ER retention in Neuro2a cells. This is the second Pcsk1 mouse model to display obesity phenotypes, contrasting knockout mouse alleles. This model will be useful in investigating the basis of endocrine disease resulting from prohormone processing defects.
Collapse
Affiliation(s)
- Nor I A Muhsin
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - Liz Bentley
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - Ying Bai
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - Michelle Goldsworthy
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - Roger D Cox
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK.
| |
Collapse
|
26
|
Tam V, Patel N, Turcotte M, Bossé Y, Paré G, Meyre D. Benefits and limitations of genome-wide association studies. Nat Rev Genet 2019; 20:467-484. [PMID: 31068683 DOI: 10.1038/s41576-019-0127-1] [Citation(s) in RCA: 930] [Impact Index Per Article: 186.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Genome-wide association studies (GWAS) involve testing genetic variants across the genomes of many individuals to identify genotype-phenotype associations. GWAS have revolutionized the field of complex disease genetics over the past decade, providing numerous compelling associations for human complex traits and diseases. Despite clear successes in identifying novel disease susceptibility genes and biological pathways and in translating these findings into clinical care, GWAS have not been without controversy. Prominent criticisms include concerns that GWAS will eventually implicate the entire genome in disease predisposition and that most association signals reflect variants and genes with no direct biological relevance to disease. In this Review, we comprehensively assess the benefits and limitations of GWAS in human populations and discuss the relevance of performing more GWAS.
Collapse
Affiliation(s)
- Vivian Tam
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Nikunj Patel
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Michelle Turcotte
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Yohan Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec-Université Laval, Québec City, Québec, Canada.,Department of Molecular Medicine, Laval University, Québec City, Quebec, Canada
| | - Guillaume Paré
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada.,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - David Meyre
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada. .,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada. .,Inserm UMRS 954 N-GERE (Nutrition-Genetics-Environmental Risks), University of Lorraine, Faculty of Medicine, Nancy, France.
| |
Collapse
|
27
|
Jarvela TS, Shakya M, Bachor T, White A, Low MJ, Lindberg I. Reduced Stability and pH-Dependent Activity of a Common Obesity-Linked PCSK1 Polymorphism, N221D. Endocrinology 2019; 160:2630-2645. [PMID: 31504391 PMCID: PMC6892424 DOI: 10.1210/en.2019-00418] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/26/2019] [Indexed: 02/06/2023]
Abstract
Common mutations in the human prohormone convertase (PC)1/3 gene (PCKSI) are linked to increased risk of obesity. Previous work has shown that the rs6232 single-nucleotide polymorphism (N221D) results in slightly decreased activity, although whether this decrease underlies obesity risk is not clear. We observed significantly decreased activity of the N221D PC1/3 enzyme at the pH of the trans-Golgi network; at this pH, the mutant enzyme was less stable than wild-type enzyme. Recombinant N221D PC1/3 also showed enhanced susceptibility to heat stress. Enhanced susceptibility to tunicamycin-induced endoplasmic reticulum stress was observed in AtT-20/PC2 cell clones in which murine PC1/3 was replaced by human N221D PC1/3, as compared with wild-type human PC1/3. However, N221D PC1/3-expressing AtT-20/PC2 clones processed proopiomelanocortin to α-MSH similarly to wild-type PC1/3. We also generated a CRISPR-edited mouse line expressing the N221D mutation in the PCKSI gene. When homozygous N221D mice were fed either a standard or a high-fat diet, we found no increase in body weight compared with their wild-type sibling controls. Sexual dimorphism was observed in pituitary ACTH for both genotypes, with females exhibiting lower levels of pituitary ACTH. In contrast, hypothalamic α-MSH content for both genotypes was higher in females compared with males. Hypothalamic corticotropin-like intermediate peptide content was higher in wild-type females compared with wild-type, but not N221D, males. Taken together, these data suggest that the increased obesity risk linked to the N221D allele in humans may be due in part to PC1/3-induced loss of resilience to stressors rather than strictly to decreased enzymatic activity on peptide precursors.
Collapse
Affiliation(s)
- Timothy S Jarvela
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Surbhi
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Manita Shakya
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Tomas Bachor
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Anne White
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Malcolm J Low
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
- Correspondence: Iris Lindberg, PhD, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn Street, Room S267, Baltimore, Maryland 21210. E-mail:
| |
Collapse
|
28
|
Cooiman M, Kleinendorst L, Aarts E, Janssen I, van Amstel HP, Blakemore A, Hazebroek E, Meijers-Heijboer H, van der Zwaag B, Berends F, van Haelst M. Genetic Obesity and Bariatric Surgery Outcome in 1014 Patients with Morbid Obesity. Obes Surg 2019; 30:470-477. [DOI: 10.1007/s11695-019-04184-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
29
|
Niazi RK, Gjesing AP, Hollensted M, Have CT, Borisevich D, Grarup N, Pedersen O, Ullah A, Shahid G, Shafqat I, Gul A, Hansen T. Screening of 31 genes involved in monogenic forms of obesity in 23 Pakistani probands with early-onset childhood obesity: a case report. BMC MEDICAL GENETICS 2019; 20:152. [PMID: 31488071 PMCID: PMC6727494 DOI: 10.1186/s12881-019-0886-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 08/29/2019] [Indexed: 11/10/2022]
Abstract
BACKGROUND Consanguine families display a high degree of homozygosity which increases the risk of family members suffering from autosomal recessive disorders. Thus, homozygous mutations in monogenic obesity genes may be a more frequent cause of childhood obesity in a consanguineous population. METHODS We identified 23 probands from 23 Pakistani families displaying autosomal recessive obesity. We have previously excluded mutations in MC4R, LEP and LEPR in all probands. Using a chip-based, target-region capture array, 31 genes involved in monogenic forms of obesity, were screened in all probands. RESULTS We identified 31 rare non-synonymous possibly pathogenic variants (28 missense and three nonsense) within the 31 selected genes. All variants were heterozygous, thus no homozygous pathogenic variants were found. Two of the rare heterozygous nonsense variants identified (p.R75X and p.R481X) were found in BBS9 within one proband, suggesting that obesity is caused by compound heterozygosity. Sequencing of the parents supported the compound heterozygous nature of obesity as each parent was carrying one of the variants. Subsequent clinical investigation strongly indicated that the proband had Bardet-Biedl syndrome. CONCLUSIONS Mutation screening in 31 genes among probands with severe early-onset obesity from Pakistani families did not reveal the presence of homozygous obesity causing variants. However, a compound heterozygote carrier of BBS9 mutations was identified, indicating that compound heterozygosity must not be overlooked when investigating the genetic etiology of severe childhood obesity in populations with a high degree of consanguinity.
Collapse
Affiliation(s)
- Robina Khan Niazi
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
- Children Hospital, Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan
| | - Anette Prior Gjesing
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Hollensted
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian Theil Have
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dmitrii Borisevich
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Niels Grarup
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Oluf Pedersen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Asmat Ullah
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
- Department of Molecular Biology, Shaheed Zulfiqar Ali Bhutto Medical University, PIMS, Islamabad, Pakistan
| | - Gulbin Shahid
- Children Hospital, Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan
| | - Ifrah Shafqat
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
| | - Asma Gul
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
| | - Torben Hansen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
30
|
Wang Z, Yang L, Qu S, Zhang C. CRISPR-mediated gene editing to rescue haploinsufficient obesity syndrome. Protein Cell 2019; 10:705-708. [PMID: 31124015 PMCID: PMC6776488 DOI: 10.1007/s13238-019-0635-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Zhifeng Wang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
- Research & Development Department, Sinoneural Cell and Gene Engineering Holdings Co., Ltd., Shanghai, China
| | - Liu Yang
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200092, China
| | - Shen Qu
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200092, China.
| | - Chao Zhang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China.
| |
Collapse
|
31
|
|
32
|
Tam V, Turcotte M, Meyre D. Established and emerging strategies to crack the genetic code of obesity. Obes Rev 2019; 20:212-240. [PMID: 30353704 DOI: 10.1111/obr.12770] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/27/2018] [Accepted: 08/28/2018] [Indexed: 12/11/2022]
Abstract
Tremendous progress has been made in the genetic elucidation of obesity over the past two decades, driven largely by technological, methodological and organizational innovations. Current strategies for identifying obesity-predisposing loci/genes, including cytogenetics, linkage analysis, homozygosity mapping, admixture mapping, candidate gene studies, genome-wide association studies, custom genotyping arrays, whole-exome sequencing and targeted exome sequencing, have achieved differing levels of success, and the identified loci in aggregate explain only a modest fraction of the estimated heritability of obesity. This review outlines the successes and limitations of these approaches and proposes novel strategies, including the use of exceptionally large sample sizes, the study of diverse ethnic groups and deep phenotypes and the application of innovative methods and study designs, to identify the remaining obesity-predisposing genes. The use of both established and emerging strategies has the potential to crack the genetic code of obesity in the not-too-distant future. The resulting knowledge is likely to yield improvements in obesity prediction, prevention and care.
Collapse
Affiliation(s)
- V Tam
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | - M Turcotte
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | - D Meyre
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada.,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| |
Collapse
|
33
|
Harno E, Gali Ramamoorthy T, Coll AP, White A. POMC: The Physiological Power of Hormone Processing. Physiol Rev 2019; 98:2381-2430. [PMID: 30156493 DOI: 10.1152/physrev.00024.2017] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pro-opiomelanocortin (POMC) is the archetypal polypeptide precursor of hormones and neuropeptides. In this review, we examine the variability in the individual peptides produced in different tissues and the impact of the simultaneous presence of their precursors or fragments. We also discuss the problems inherent in accurately measuring which of the precursors and their derived peptides are present in biological samples. We address how not being able to measure all the combinations of precursors and fragments quantitatively has affected our understanding of the pathophysiology associated with POMC processing. To understand how different ratios of peptides arise, we describe the role of the pro-hormone convertases (PCs) and their tissue specificities and consider the cellular processing pathways which enable regulated secretion of different peptides that play crucial roles in integrating a range of vital physiological functions. In the pituitary, correct processing of POMC peptides is essential to maintain the hypothalamic-pituitary-adrenal axis, and this processing can be disrupted in POMC-expressing tumors. In hypothalamic neurons expressing POMC, abnormalities in processing critically impact on the regulation of appetite, energy homeostasis, and body composition. More work is needed to understand whether expression of the POMC gene in a tissue equates to release of bioactive peptides. We suggest that this comprehensive view of POMC processing, with a focus on gaining a better understanding of the combination of peptides produced and their relative bioactivity, is a necessity for all involved in studying this fascinating physiological regulatory phenomenon.
Collapse
Affiliation(s)
- Erika Harno
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Thanuja Gali Ramamoorthy
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Anthony P Coll
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Anne White
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| |
Collapse
|
34
|
Neurobiological characteristics underlying metabolic differences between males and females. Prog Neurobiol 2018; 176:18-32. [PMID: 30194984 DOI: 10.1016/j.pneurobio.2018.09.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/22/2018] [Accepted: 09/01/2018] [Indexed: 12/24/2022]
Abstract
The hypothalamus is the main integrating center for metabolic control. Our understanding of how hypothalamic circuits function to control appetite and energy expenditure has increased dramatically in recent years, due to the rapid rise in the incidence of obesity and the search for effective treatments. Increasing evidence indicates that these treatments will most likely differ between males and females. Indeed, sex differences in metabolism have been demonstrated at various levels, including in two of the most studied neuronal populations involved in metabolic control: the anorexigenic proopiomelanocortin neurons and the orexigenic neuropeptide Y/Agouti-related protein neurons. Here we review what is known to date regarding the sex differences in these two neuronal populations, as well as other neuronal populations involved in metabolic control and glial cells.
Collapse
|
35
|
Stryjecki C, Alyass A, Meyre D. Ethnic and population differences in the genetic predisposition to human obesity. Obes Rev 2018; 19:62-80. [PMID: 29024387 DOI: 10.1111/obr.12604] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/17/2017] [Accepted: 08/02/2017] [Indexed: 12/22/2022]
Abstract
Obesity rates have escalated to the point of a global pandemic with varying prevalence across ethnic groups. These differences are partially explained by lifestyle factors in addition to genetic predisposition to obesity. This review provides a comprehensive examination of the ethnic differences in the genetic architecture of obesity. Using examples from evolution, heritability, admixture, monogenic and polygenic studies of obesity, we provide explanations for ethnic differences in the prevalence of obesity. The debate over definitions of race and ethnicity, the advantages and limitations of multi-ethnic studies and future directions of research are also discussed. Multi-ethnic studies have great potential to provide a better understanding of ethnic differences in the prevalence of obesity that may result in more targeted and personalized obesity treatments.
Collapse
Affiliation(s)
- C Stryjecki
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | - A Alyass
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | - D Meyre
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada.,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| |
Collapse
|
36
|
|
37
|
Abstract
Zusammenfassung
Autosomal-rezessiv vererbte Mutationen in den Genen für Leptin, Leptinrezeptor, Proopiomelanocortin (POMC) und Prohormon-Convertase (PC1) führen zu einer ausgeprägten frühkindlichen Adipositas. Patienten mit biologisch inaktivem Leptin oder Leptinmangel können mit humanem rekombinanten Leptin erfolgreich behandelt werden. Für die anderen Patienten hat sich die Behandlung mit einem α‑MSH-Analogon als erfolgreich erwiesen (POMC-Patienten) bzw. befindet sich derzeit in Erprobung.
Kodominant vererbte Mutationen im MC4R-Gen stellen die häufigste Form der monogenen Adipositas dar. Eine kausale Therapie ist hier allerdings nicht möglich.
Es sind inzwischen noch weitere, autosomal-rezessiv vererbte Genmutationen identifiziert worden, die ebenfalls mit einer ausgeprägten Adipositas assoziiert sind. Die meisten dieser Mutationen liegen in Genen, die in die Signaltransduktion von MC4R oder dem Leptinrezeptor involviert sind. Auch für diese Patienten gibt es aktuell noch keine kausale Therapie.
Schlussfolgerung: Bei Patienten mit extremer frühkindlicher Adipositas sollte eine molekulargenetische Diagnostik eingeleitet werden, da die Diagnosestellung für die Betroffenen und ihre Familie eine enorme Erleichterung bedeuten kann. Außerdem gewinnen die Familien Klarheit über das Wiederholungsrisiko und eventuell ist sogar eine kausale oder zumindest optimierte Therapie möglich.
Collapse
Affiliation(s)
- Julia von Schnurbein
- Aff1 grid.410712.1 Klinik für Kinder- und Jugendmedizin, Zentrum für Seltene Erkrankungen (ZSE) Ulm, Sektion Pädiatrische Endokrinologie und Diabetologie Universitätsklinik für Kinder- und Jugendmedizin Eythstr. 24 89075 Ulm Deutschland
| | - Martin Wabitsch
- Aff1 grid.410712.1 Klinik für Kinder- und Jugendmedizin, Zentrum für Seltene Erkrankungen (ZSE) Ulm, Sektion Pädiatrische Endokrinologie und Diabetologie Universitätsklinik für Kinder- und Jugendmedizin Eythstr. 24 89075 Ulm Deutschland
| |
Collapse
|
38
|
Affiliation(s)
- David Meyre
- Department of Health Research Methods, Evidence, and Impact and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| |
Collapse
|
39
|
Nordang GBN, Busk ØL, Tveten K, Hanevik HI, Fell AKM, Hjelmesæth J, Holla ØL, Hertel JK. Next-generation sequencing of the monogenic obesity genes LEP, LEPR, MC4R, PCSK1 and POMC in a Norwegian cohort of patients with morbid obesity and normal weight controls. Mol Genet Metab 2017; 121:51-56. [PMID: 28377240 DOI: 10.1016/j.ymgme.2017.03.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Rare sequence variants in at least five genes are known to cause monogenic obesity. In this study we aimed to investigate the prevalence of, and characterize, rare coding and splice site variants in LEP, LEPR, MC4R, PCSK1 and POMC in patients with morbid obesity and normal weight controls. METHOD Targeted next-generation sequencing of all exons in LEP, LEPR, MC4R, PCSK1 and POMC was performed in 485 patients with morbid obesity and 327 normal weight population-based controls from Norway. RESULTS In total 151 variants were detected. Twenty-eight (18.5%) of these were rare, coding or splice variants and five (3.3%) were novel. All individuals, except one control, were heterozygous for the 28 variants, and the distribution of the rare variants showed a significantly higher carrier frequency among cases than controls (9.9% vs. 4.9%, p=0.011). Four variants in MC4R were classified as pathogenic or likely pathogenic. CONCLUSION Four cases (0.8%) of monogenic obesity were detected, all due to MC4R variants previously linked to monogenic obesity. Significant differences in carrier frequencies among patients with morbid obesity and normal weight controls suggest an association between heterozygous rare coding variants in these five genes and morbid obesity. However, additional studies in larger cohorts and functional testing of the novel variants identified are required to confirm the findings.
Collapse
Affiliation(s)
- Gry B N Nordang
- Morbid Obesity Centre, Vestfold Hospital Trust, Tønsberg, Norway; Department of Occupational and Environmental Medicine, Telemark Hospital, Skien, Norway; Section of Medical Genetics, Department of Laboratory Medicine, Telemark Hospital, Skien, Norway.
| | - Øyvind L Busk
- Section of Medical Genetics, Department of Laboratory Medicine, Telemark Hospital, Skien, Norway
| | - Kristian Tveten
- Section of Medical Genetics, Department of Laboratory Medicine, Telemark Hospital, Skien, Norway
| | | | - Anne Kristin M Fell
- Department of Occupational and Environmental Medicine, Telemark Hospital, Skien, Norway
| | - Jøran Hjelmesæth
- Morbid Obesity Centre, Vestfold Hospital Trust, Tønsberg, Norway; Department of Endocrinology, Morbid Obesity and Preventive Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Øystein L Holla
- Section of Medical Genetics, Department of Laboratory Medicine, Telemark Hospital, Skien, Norway
| | - Jens K Hertel
- Morbid Obesity Centre, Vestfold Hospital Trust, Tønsberg, Norway
| |
Collapse
|
40
|
Recent progress in genetics, epigenetics and metagenomics unveils the pathophysiology of human obesity. Clin Sci (Lond) 2017; 130:943-86. [PMID: 27154742 DOI: 10.1042/cs20160136] [Citation(s) in RCA: 227] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/24/2016] [Indexed: 12/19/2022]
Abstract
In high-, middle- and low-income countries, the rising prevalence of obesity is the underlying cause of numerous health complications and increased mortality. Being a complex and heritable disorder, obesity results from the interplay between genetic susceptibility, epigenetics, metagenomics and the environment. Attempts at understanding the genetic basis of obesity have identified numerous genes associated with syndromic monogenic, non-syndromic monogenic, oligogenic and polygenic obesity. The genetics of leanness are also considered relevant as it mirrors some of obesity's aetiologies. In this report, we summarize ten genetically elucidated obesity syndromes, some of which are involved in ciliary functioning. We comprehensively review 11 monogenic obesity genes identified to date and their role in energy maintenance as part of the leptin-melanocortin pathway. With the emergence of genome-wide association studies over the last decade, 227 genetic variants involved in different biological pathways (central nervous system, food sensing and digestion, adipocyte differentiation, insulin signalling, lipid metabolism, muscle and liver biology, gut microbiota) have been associated with polygenic obesity. Advances in obligatory and facilitated epigenetic variation, and gene-environment interaction studies have partly accounted for the missing heritability of obesity and provided additional insight into its aetiology. The role of gut microbiota in obesity pathophysiology, as well as the 12 genes associated with lipodystrophies is discussed. Furthermore, in an attempt to improve future studies and merge the gap between research and clinical practice, we provide suggestions on how high-throughput '-omic' data can be integrated in order to get closer to the new age of personalized medicine.
Collapse
|
41
|
Functional and clinical relevance of novel and known PCSK1 variants for childhood obesity and glucose metabolism. Mol Metab 2016; 6:295-305. [PMID: 28271036 PMCID: PMC5323889 DOI: 10.1016/j.molmet.2016.12.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 11/22/2016] [Accepted: 12/01/2016] [Indexed: 01/28/2023] Open
Abstract
Objective Variants in Proprotein Convertase Subtilisin/Kexin Type 1 (PCSK1) may be causative for obesity as suggested by monogenic cases and association studies. Here we assessed the functional relevance in experimental studies and the clinical relevance through detailed metabolic phenotyping of newly identified and known PCSK1 variants in children. Results In 52 obese children selected for elevated proinsulin levels and/or impaired glucose tolerance, we found eight known variants and two novel heterozygous variants (c.1095 + 1G > A and p.S24C) by sequencing the PCSK1 gene. Patients with the new variants presented with extreme obesity, impaired glucose tolerance, and PCOS. Functionally, c.1095 + 1G > A caused skipping of exon8 translation and a complete loss of enzymatic activity. The protein was retained within the endoplasmic reticulum (ER) causing ER stress. The p.S24C variant had no functional effect on protein size, cell trafficking, or enzymatic activity. The known variants rs6230, rs35753085, and rs725522 in the 5′ end did not affect PCSK1 promoter activity. In clinical association studies in 1673 lean and obese children, we confirmed associations of rs6232 and rs6234 with BMI-SDS and of rs725522 with glucose stimulated insulin secretion and Matsuda index. We did not find the new variants in any other subjects. Conclusions We identified and functionally characterized two rare novel PCSK1 variants of which c.1095 + 1G > A caused complete loss of protein function. In addition to confirming rs6232 and rs6234 in PCSK1 as polygenic risk variants for childhood obesity, we describe an association of rs725522 with insulin metabolism. Our results support the contribution of PCSK1 variants to obesity predisposition in children. We identified two novel variants in PCSK1 in severely obese adolescents. The phenotype of these two heterozygous carriers is more severe than in “common childhood obesity”. The ΔEx8 variant leads to a truncated protein with a complete loss of function, which is retained within the ER. For common variant rs725522 detailed metabolic phenotyping revealed impaired glucose dynamics. Overall, variants in PCSK1 are not only associated with childhood obesity, but a more severe phenotype than in BMI-matched controls.
Collapse
|
42
|
Seidah NG, Abifadel M, Prost S, Boileau C, Prat A. The Proprotein Convertases in Hypercholesterolemia and Cardiovascular Diseases: Emphasis on Proprotein Convertase Subtilisin/Kexin 9. Pharmacol Rev 2016; 69:33-52. [DOI: 10.1124/pr.116.012989] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
|
43
|
Stijnen P, Ramos-Molina B, O'Rahilly S, Creemers JWM. PCSK1 Mutations and Human Endocrinopathies: From Obesity to Gastrointestinal Disorders. Endocr Rev 2016; 37:347-71. [PMID: 27187081 DOI: 10.1210/er.2015-1117] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Prohormone convertase 1/3, encoded by the PCSK1 gene, is a serine endoprotease that is involved in the processing of a variety of proneuropeptides and prohormones. Humans who are homozygous or compound heterozygous for loss-of-function mutations in PCSK1 exhibit a variable and pleiotropic syndrome consisting of some or all of the following: obesity, malabsorptive diarrhea, hypogonadotropic hypogonadism, altered thyroid and adrenal function, and impaired regulation of plasma glucose levels in association with elevated circulating proinsulin-to-insulin ratio. Recently, more common variants in the PCSK1 gene have been found to be associated with alterations in body mass index, increased circulating proinsulin levels, and defects in glucose homeostasis. This review provides an overview of the endocrinopathies and other disorders observed in prohormone convertase 1/3-deficient patients, discusses the possible biochemical basis for these manifestations of the disease, and proposes a model whereby certain missense mutations in PCSK1 may result in proteins with a dominant negative action.
Collapse
Affiliation(s)
- Pieter Stijnen
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Bruno Ramos-Molina
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Stephen O'Rahilly
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - John W M Creemers
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| |
Collapse
|
44
|
Early Clinical Diagnosis of PC1/3 Deficiency in a Patient With a Novel Homozygous PCSK1 Splice-Site Mutation. J Pediatr Gastroenterol Nutr 2016; 62:577-80. [PMID: 26488123 DOI: 10.1097/mpg.0000000000001018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Autosomal recessive proprotein convertase 1/3 (PC1/3) deficiency, caused by mutations in the PCSK1 gene, is characterized by severe congenital malabsorptive diarrhea, early-onset obesity, and certain endocrine abnormalities. We suspected PC1/3 deficiency in a 4-month-old girl based on the presence of congenital diarrhea and polyuria. Sequencing the whole coding region and splice sites detected a novel homozygous PCSK1 splice-site mutation, c.544-2A>G, in the patient. The mutation resulted in the skipping of exon 5, the generation of a premature termination codon, and nonsense-mediated PCSK1 messenger ribonucleic acid decay, which was demonstrated in complementary DNA derived from fibroblasts.
Collapse
|
45
|
Ramos-Molina B, Martin MG, Lindberg I. PCSK1 Variants and Human Obesity. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 140:47-74. [PMID: 27288825 DOI: 10.1016/bs.pmbts.2015.12.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PCSK1, encoding prohormone convertase 1/3 (PC1/3), was one of the first genes linked to monogenic early-onset obesity. PC1/3 is a protease involved in the biosynthetic processing of a variety of neuropeptides and prohormones in endocrine tissues. PC1/3 activity is essential for the activating cleavage of many peptide hormone precursors implicated in the regulation of food ingestion, glucose homeostasis, and energy homeostasis, for example, proopiomelanocortin, proinsulin, proglucagon, and proghrelin. A large number of genome-wide association studies in a variety of different populations have now firmly established a link between three PCSK1 polymorphisms frequent in the population and increased risk of obesity. Human subjects with PC1/3 deficiency, a rare autosomal-recessive disorder caused by the presence of loss-of-function mutations in both alleles, are obese and display a complex set of endocrinopathies. Increasing numbers of genetic diagnoses of infants with persistent diarrhea has recently led to the finding of many novel PCSK1 mutations. PCSK1-deficient infants experience severe intestinal malabsorption during the first years of life, requiring controlled nutrition; these children then become hyperphagic, with associated obesity. The biochemical characterization of novel loss-of-function PCSK1 mutations has resulted in the discovery of new pathological mechanisms affecting the cell biology of the endocrine cell beyond simple loss of enzyme activity, for example, dominant-negative effects of certain mutants on wild-type PC1/3 protein, and activation of the cellular unfolded protein response by endoplasmic reticulum-retained mutants. A better understanding of these molecular and cellular pathologies may illuminate possible treatments for the complex endocrinopathy of PCSK1 deficiency, including obesity.
Collapse
Affiliation(s)
- B Ramos-Molina
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - M G Martin
- Department of Pediatrics, Division of Gastroenterology and Nutrition, Mattel Children's Hospital and the David Geffen School of Medicine, Los Angeles, CA, United States of America
| | - I Lindberg
- Department of Anatomy and Neurobiology, University of Maryland, Baltimore, MD, United States of America.
| |
Collapse
|
46
|
Stijnen P, Brouwers B, Dirkx E, Ramos-Molina B, Van Lommel L, Schuit F, Thorrez L, Declercq J, Creemers JWM. Endoplasmic reticulum-associated degradation of the mouse PC1/3-N222D hypomorph and human PCSK1 mutations contributes to obesity. Int J Obes (Lond) 2016; 40:973-81. [PMID: 26786350 DOI: 10.1038/ijo.2016.3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 12/03/2015] [Accepted: 12/22/2015] [Indexed: 12/26/2022]
Abstract
BACKGROUND The proprotein convertase 1/3 (PC1/3), encoded by proprotein convertase subtilisin/kexin type 1 (PCSK1), cleaves and hence activates several orexigenic and anorexigenic proproteins. Congenital inactivation of PCSK1 leads to obesity in human but not in mice. However, a mouse model harboring the hypomorphic mutation N222D is obese. It is not clear why the mouse models differ in phenotype. METHODS Gene expression analysis was performed with pancreatic islets from Pcsk1(N222D/N222D) mice. Subsequently, biosynthesis, maturation, degradation and activity were studied in islets, pituitary, hypothalamus and cell lines. Coimmunoprecipitation of PC1/3-N222D and human PC1/3 variants associated with obesity with the endoplasmic reticulum (ER) chaperone BiP was studied in cell lines. RESULTS Gene expression analysis of islets of Pcsk1(N222D/N222D) mice showed enrichment of gene sets related to the proteasome and the unfolded protein response. Steady-state levels of PC1/3-N222D and in particular the carboxy-terminally processed form were strongly reduced in islets, pituitary and hypothalamus. However, impairment of substrate cleavage was tissue dependent. Proinsulin processing was drastically reduced, while processing of proopiomelanocortin (POMC) to adrenocorticotropic hormone (ACTH) in pituitary was only mildly impaired. Growth hormone expression and IGF-1 levels were normal, indicating near-normal processing of hypothalamic proGHRH. PC1/3-N222D binds to BiP and is rapidly degraded by the proteasome. Analysis of human PC1/3 obesity-associated mutations showed increased binding to BiP and prolonged intracellular retention for all investigated mutations, in particular for PC1/3-T175M, PC1/3-G226R and PC1/3-G593R. CONCLUSIONS This study demonstrates that the hypomorphic mutation in Pcsk1(N222D) mice has an effect on catalytic activity in pancreatic islets, pituitary and hypothalamus. Reduced substrate processing activity in Pcsk1(N222D/N222D) mice is due to enhanced degradation in addition to reduced catalytic activity of the mutant. PC1/3-N222D binds to BiP, suggesting impaired folding and reduced stability. Enhanced BiP binding is also observed in several human obesity-associated PC1/3 variants, suggesting a common mechanism.
Collapse
Affiliation(s)
- P Stijnen
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - B Brouwers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - E Dirkx
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - B Ramos-Molina
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - L Van Lommel
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - F Schuit
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - L Thorrez
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - J Declercq
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - J W M Creemers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| |
Collapse
|
47
|
Blanco EH, Ramos-Molina B, Lindberg I. Revisiting PC1/3 Mutants: Dominant-Negative Effect of Endoplasmic Reticulum-Retained Mutants. Endocrinology 2015; 156. [PMID: 26207343 PMCID: PMC4588832 DOI: 10.1210/en.2015-1068] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Prohormone convertase 1/3 (PC1/3), encoded by the gene PCSK1, is critical for peptide hormone synthesis. An increasing number of studies have shown that inactivating mutations in PCSK1 are correlated with endocrine pathologies ranging from intestinal dysfunction to morbid obesity, whereas the common nonsynonymous polymorphisms rs6232 (N221D) and rs6234-rs6235 (Q665E-S690T) are highly associated with obesity risk. In this report, we revisited the biochemical and cellular properties of PC1/3 variants in the context of a wild-type PC1/3 background instead of the S357G hypermorph background used for all previous studies. In the wild-type background the PC1/3 N221D variant exhibited 30% lower enzymatic activity in a fluorogenic assay than wild-type PC1/3; this inhibition was greater than that detected in an equivalent experiment using the PC1/3 S357G background. A PC1/3 variant with the linked carboxyl-terminal polymorphisms Q665E-S690T did not show this difference. We also analyzed the biochemical properties of 2 PC1/3 mutants, G209R and G593R, which are retained in the endoplasmic reticulum (ER), and studied their effects on wild-type PC1/3. The expression of ER-retained mutants induced ER stress markers and also resulted in dominant-negative blockade of wild-type PC1/3 prodomain cleavage and decreased expression of wild-type PC1/3, suggesting facilitation of the entry of wild-type protein to a degradative proteasomal pathway. Dominant-negative effects of PC1/3 mutations on the expression and maturation of wild-type protein, with consequential effects on PC1/3 availability, add a new element which must be considered in population and clinical studies of this gene.
Collapse
Affiliation(s)
- Elias H Blanco
- Department of Anatomy and Neurobiology, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Bruno Ramos-Molina
- Department of Anatomy and Neurobiology, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| |
Collapse
|
48
|
Rohden F, Costa CS, Hammes TO, Margis R, Padoin AV, Mottin CC, Guaragna RM. Obesity associated with type 2 diabetes mellitus is linked to decreased PC1/3 mRNA expression in the Jejunum. Obes Surg 2015; 24:2075-81. [PMID: 24831459 DOI: 10.1007/s11695-014-1279-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Bariatric surgery is the most effective therapeutic option for obesity and its complications, especially in type 2 diabetes. The aim of this study was to investigate the messenger RNA (mRNA) gene expression of proglucagon, glucose-dependent insulinotropic peptide (GIP), prohormone convertase 1/3 (PC1/3), and dipeptidyl peptidase-IV (DPP-IV) in jejunum cells of the morbidly obese (OB) non type 2 diabetes mellitus (NDM2) and type 2 diabetes mellitus (T2DM), to determine the molecular basis of incretin secretion after bariatric surgery. METHODS Samples of jejunal mucosa were obtained from 20 NDM2 patients: removal of a section of the jejunum about 60 cm distal to the ligament of Treitz and 18 T2DM patients: removal of a section of the jejunum about 100 cm distal to the ligament of Treitz. Total RNA was extracted using TRIzol. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) was carried out. Samples were sequenced to PC1/3 by ACTGene Análises Moleculares Ltd. Immuno content was quantified with a fluorescence microscope. RESULTS T2DM showed decreased PC1/3 mRNA expression in the primers tested (primer a, p=0.014; primer b, p=0.048). Many patients (36.5 %) did not express PC1/3 mRNA. NDM2 and T2DM subjects showed nonsignificantly different proglucagon, GIP, and DPP-IV mRNA expression. The immuno contents of glucagon-like peptide-1 and GIP decreased in T2DM jejunum, but incubation with high glucose stimulated the immuno contents. CONCLUSIONS The results suggest that bioactivation of pro-GIP and proglucagon could be impaired by the lower expression of PC1/3 mRNA in jejunum cells of obese patients with T2DM. However, after surgery, food could activate this system and improve glucose levels in these patients.
Collapse
Affiliation(s)
- Francieli Rohden
- Departamento de Bioquímica, ICBS, UFRGS, Rua Ramiro Barcelos 2600 - anexo, CEP 90.035-003, Porto Alegre, RS, Brazil
| | | | | | | | | | | | | |
Collapse
|
49
|
Williamson DM, Elferich J, Shinde U. Mechanism of Fine-tuning pH Sensors in Proprotein Convertases: IDENTIFICATION OF A pH-SENSING HISTIDINE PAIR IN THE PROPEPTIDE OF PROPROTEIN CONVERTASE 1/3. J Biol Chem 2015; 290:23214-25. [PMID: 26229104 DOI: 10.1074/jbc.m115.665430] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Indexed: 12/15/2022] Open
Abstract
The propeptides of proprotein convertases (PCs) regulate activation of cognate protease domains by sensing pH of their organellar compartments as they transit the secretory pathway. Earlier experimental work identified a conserved histidine-encoded pH sensor within the propeptide of the canonical PC, furin. To date, whether protonation of this conserved histidine is solely responsible for PC activation has remained unclear because of the observation that various PC paralogues are activated at different organellar pH values. To ascertain additional determinants of PC activation, we analyzed PC1/3, a paralogue of furin that is activated at a pH of ∼5.4. Using biophysical, biochemical, and cell-based methods, we mimicked the protonation status of various histidines within the propeptide of PC1/3 and examined how such alterations can modulate pH-dependent protease activation. Our results indicate that whereas the conserved histidine plays a crucial role in pH sensing and activation of this protease an additional histidine acts as a "gatekeeper" that fine-tunes the sensitivity of the PC1/3 propeptide to facilitate the release inhibition at higher proton concentrations when compared with furin. Coupled with earlier analyses that highlighted the enrichment of the amino acid histidine within propeptides of secreted eukaryotic proteases, our work elucidates how secreted proteases have evolved to exploit the pH of the secretory pathway by altering the spatial juxtaposition of titratable groups to regulate their activity in a spatiotemporal fashion.
Collapse
Affiliation(s)
- Danielle M Williamson
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Johannes Elferich
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Ujwal Shinde
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| |
Collapse
|
50
|
Sandoval DA, D'Alessio DA. Physiology of proglucagon peptides: role of glucagon and GLP-1 in health and disease. Physiol Rev 2015; 95:513-48. [PMID: 25834231 DOI: 10.1152/physrev.00013.2014] [Citation(s) in RCA: 302] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The preproglucagon gene (Gcg) is expressed by specific enteroendocrine cells (L-cells) of the intestinal mucosa, pancreatic islet α-cells, and a discrete set of neurons within the nucleus of the solitary tract. Gcg encodes multiple peptides including glucagon, glucagon-like peptide-1, glucagon-like peptide-2, oxyntomodulin, and glicentin. Of these, glucagon and GLP-1 have received the most attention because of important roles in glucose metabolism, involvement in diabetes and other disorders, and application to therapeutics. The generally accepted model is that GLP-1 improves glucose homeostasis indirectly via stimulation of nutrient-induced insulin release and by reducing glucagon secretion. Yet the body of literature surrounding GLP-1 physiology reveals an incompletely understood and complex system that includes peripheral and central GLP-1 actions to regulate energy and glucose homeostasis. On the other hand, glucagon is established principally as a counterregulatory hormone, increasing in response to physiological challenges that threaten adequate blood glucose levels and driving glucose production to restore euglycemia. However, there also exists a potential role for glucagon in regulating energy expenditure that has recently been suggested in pharmacological studies. It is also becoming apparent that there is cross-talk between the proglucagon derived-peptides, e.g., GLP-1 inhibits glucagon secretion, and some additive or synergistic pharmacological interaction between GLP-1 and glucagon, e.g., dual glucagon/GLP-1 agonists cause more weight loss than single agonists. In this review, we discuss the physiological functions of both glucagon and GLP-1 by comparing and contrasting how these peptides function, variably in concert and opposition, to regulate glucose and energy homeostasis.
Collapse
Affiliation(s)
- Darleen A Sandoval
- Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - David A D'Alessio
- Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| |
Collapse
|