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Chen YC, Taylor AJ, Fulcher JM, Swensen AC, Dai XQ, Komba M, Wrightson KL, Fok K, Patterson AE, Klein Geltink RI, MacDonald PE, Qian WJ, Verchere CB. Deletion of Carboxypeptidase E in β-Cells Disrupts Proinsulin Processing but Does Not Lead to Spontaneous Development of Diabetes in Mice. Diabetes 2023; 72:1277-1288. [PMID: 37364047 PMCID: PMC10450824 DOI: 10.2337/db22-0945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 06/22/2023] [Indexed: 06/28/2023]
Abstract
Carboxypeptidase E (CPE) facilitates the conversion of prohormones into mature hormones and is highly expressed in multiple neuroendocrine tissues. Carriers of CPE mutations have elevated plasma proinsulin and develop severe obesity and hyperglycemia. We aimed to determine whether loss of Cpe in pancreatic β-cells disrupts proinsulin processing and accelerates development of diabetes and obesity in mice. Pancreatic β-cell-specific Cpe knockout mice (βCpeKO; Cpefl/fl x Ins1Cre/+) lack mature insulin granules and have elevated proinsulin in plasma; however, glucose-and KCl-stimulated insulin secretion in βCpeKO islets remained intact. High-fat diet-fed βCpeKO mice showed weight gain and glucose tolerance comparable with those of Wt littermates. Notably, β-cell area was increased in chow-fed βCpeKO mice and β-cell replication was elevated in βCpeKO islets. Transcriptomic analysis of βCpeKO β-cells revealed elevated glycolysis and Hif1α-target gene expression. On high glucose challenge, β-cells from βCpeKO mice showed reduced mitochondrial membrane potential, increased reactive oxygen species, reduced MafA, and elevated Aldh1a3 transcript levels. Following multiple low-dose streptozotocin injections, βCpeKO mice had accelerated development of hyperglycemia with reduced β-cell insulin and Glut2 expression. These findings suggest that Cpe and proper proinsulin processing are critical in maintaining β-cell function during the development of hyperglycemia. ARTICLE HIGHLIGHTS Carboxypeptidase E (Cpe) is an enzyme that removes the carboxy-terminal arginine and lysine residues from peptide precursors. Mutations in CPE lead to obesity and type 2 diabetes in humans, and whole-body Cpe knockout or mutant mice are obese and hyperglycemic and fail to convert proinsulin to insulin. We show that β-cell-specific Cpe deletion in mice (βCpeKO) does not lead to the development of obesity or hyperglycemia, even after prolonged high-fat diet treatment. However, β-cell proliferation rate and β-cell area are increased, and the development of hyperglycemia induced by multiple low-dose streptozotocin injections is accelerated in βCpeKO mice.
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Affiliation(s)
- Yi-Chun Chen
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Austin J. Taylor
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - James M. Fulcher
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA
| | - Adam C. Swensen
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA
| | - Xiao-Qing Dai
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Mitsuhiro Komba
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | | | - Kenny Fok
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Annette E. Patterson
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ramon I. Klein Geltink
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Wei-Jun Qian
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA
| | - C. Bruce Verchere
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Molecular Medicine and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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2
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Fan FC, Du Y, Zheng WH, Loh YP, Cheng Y. Carboxypeptidase E conditional knockout mice exhibit learning and memory deficits and neurodegeneration. Transl Psychiatry 2023; 13:135. [PMID: 37100779 PMCID: PMC10133319 DOI: 10.1038/s41398-023-02429-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 04/03/2023] [Accepted: 04/06/2023] [Indexed: 04/28/2023] Open
Abstract
Carboxypeptidase E (CPE) is a multifunctional protein with many nonenzymatic functions in various systems. Previous studies using CPE knock-out mice have shown that CPE has neuroprotective effects against stress and is involved in learning and memory. However, the functions of CPE in neurons are still largely unknown. Here we used a Camk2a-Cre system to conditionally knockout CPE in neurons. The wild-type, CPEflox/-, and CPEflox/flox mice were weaned, ear-tagged, and tail clipped for genotyping at 3 weeks old, and they underwent open field, object recognition, Y-maze, and fear conditioning tests at 8 weeks old. The CPEflox/flox mice had normal body weight and glucose metabolism. The behavioral tests showed that CPEflox/flox mice had impaired learning and memory compared with wild-type and CPEflox/- mice. Surprisingly, the subiculum (Sub) region of CPEflox/flox mice was completely degenerated, unlike the CPE full knockout mice, which exhibit CA3 region neurodegeneration. In addition, doublecortin immunostaining suggested that neurogenesis in the dentate gyrus of the hippocampus was significantly reduced in CPEflox/flox mice. Interestingly, TrkB phosphorylation in the hippocampus was downregulated in CPEflox/flox mice, but brain-derived neurotrophic factor levels were not. In both the hippocampus and dorsal medial prefrontal cortex, we observed reduced MAP2 and GFAP expression in CPEflox/flox mice. Taken together, the results of this study demonstrate that specific neuronal CPE knockout leads to central nervous system dysfunction in mice, including learning and memory deficits, hippocampal Sub degeneration and impaired neurogenesis.
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Affiliation(s)
- Fang-Cheng Fan
- Key Laboratory of Ethnomedicine of Ministry of Education, Center on Translational Neuroscience, School of Pharmacy, Minzu University of China, Beijing, China
| | - Yang Du
- Key Laboratory of Ethnomedicine of Ministry of Education, Center on Translational Neuroscience, School of Pharmacy, Minzu University of China, Beijing, China
| | - Wen-Hui Zheng
- Key Laboratory of Ethnomedicine of Ministry of Education, Center on Translational Neuroscience, School of Pharmacy, Minzu University of China, Beijing, China
| | - Y Peng Loh
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Yong Cheng
- Key Laboratory of Ethnomedicine of Ministry of Education, Center on Translational Neuroscience, School of Pharmacy, Minzu University of China, Beijing, China.
- College of Life and Environmental Sciences, Minzu University of China, Beijing, China.
- Institute of National Security, Minzu University of China, Beijing, China.
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3
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Fricker LD, Lemos Duarte M, Jeltyi A, Lueptow L, Fakira AK, Tashima AK, Hochgeschwender U, Wetsel WC, Devi LA. Mice heterozygous for a null mutation of Cpe show reduced expression of carboxypeptidase E mRNA and enzyme activity but normal physiology, behavior, and levels of neuropeptides. Brain Res 2022; 1789:147951. [PMID: 35618016 DOI: 10.1016/j.brainres.2022.147951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/18/2022] [Accepted: 05/19/2022] [Indexed: 11/02/2022]
Abstract
Carboxypeptidase E (CPE) is an essential enzyme that contributes to the biosynthesis of the vast majority of neuropeptides and peptide hormones. There are several reports claiming that small decreases in CPE activity cause physiological changes in animals and/or cultured cells, but these studies did not provide evidence that neuropeptide levels were affected by decreased CPE activity. In the present study, we tested if CPE is a rate-limiting enzyme in neuropeptide production using CpeNeo mice, which contain a neomycin cassette within the Cpe gene that eliminates enzyme expression. Homozygous CpeNeo/Neo mice show defects found in Cpefat/fat and/or Cpe global knockout (KO) mice, including greatly decreased levels of most neuropeptides, severely impaired fertility, depressive-like behavior, adult-onset obesity, and anxiety-like behavior. Removal of the neomycin cassette with Flp recombinase under a germline promoter restored expression of CPE activity and resulted in normal behavioral and physiological properties, including levels of neuropeptides. Mice heterozygous for the CpeNeo allele have greatly reduced levels of Cpe mRNA and CPE-like enzymatic activity. Despite the decreased levels of Cpe expression, heterozygous CpeNeo mice are behaviorally and physiologically identical to wild-type mice, with normal levels of most neuropeptides. These results indicate that CPE is not a rate-limiting enzyme in the production of most neuropeptides, casting doubt upon studies claiming small decreases in CPE activity contribute to obesity or other physiological effects.
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Affiliation(s)
- Lloyd D Fricker
- Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461.
| | - Mariana Lemos Duarte
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
| | - Andrei Jeltyi
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
| | - Lindsay Lueptow
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
| | - Amanda K Fakira
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
| | - Alexandre K Tashima
- Department of Biochemistry, Escola Paulista de Medicina, Federal University of Sao Paulo, Sao Paulo, SP 04023-901, Brazil.
| | | | - William C Wetsel
- Departments of Psychiatry and Behavioral Sciences, Neurobiology, and Cell Biology, Duke University Medical Center, Durham, NC, 27710.
| | - Lakshmi A Devi
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
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Roberts KJ, Ariza AJ, Selvaraj K, Quadri M, Mangarelli C, Neault S, Davis EE, Binns HJ. Testing for rare genetic causes of obesity: findings and experiences from a pediatric weight management program. Int J Obes (Lond) 2022; 46:1493-1501. [PMID: 35562395 PMCID: PMC9105591 DOI: 10.1038/s41366-022-01139-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 12/23/2022]
Abstract
BACKGROUND Genetic screening for youth with obesity in the absence of syndromic findings has not been part of obesity management. For children with early onset obesity, genetic screening is recommended for those having clinical features of genetic obesity syndromes (including hyperphagia). OBJECTIVES The overarching goal of this work is to report the findings and experiences from one pediatric weight management program that implemented targeted sequencing analysis for genes known to cause rare genetic disorders of obesity. SUBJECTS/METHODS This exploratory study evaluated youth tested over an 18-month period using a panel of 40-genes in the melanocortin 4 receptor pathway. Medical records were reviewed for demographic and visit information, including body mass index (BMI) percent of 95th percentile (%BMIp95) and two eating behaviors. RESULTS Of 117 subjects: 51.3% were male; 53.8% Hispanic; mean age 10.2 years (SD 3.8); mean %BMIp95 157% (SD 29%). Most subjects were self- or caregiver-reported to have overeating to excess or binge eating (80.3%) and sneaking food or eating in secret (59.0%). Among analyzed genes, 72 subjects (61.5%) had at least one variant reported; 50 (42.7%) had a single variant reported; 22 (18.8%) had 2-4 variants reported; most variants were rare (<0.05% minor allele frequency [MAF]), and of uncertain significance; all variants were heterozygous. Nine subjects (7.7%) had a variant reported as PSCK1 "risk" or MC4R "likely pathogenic"; 39 (33.3%) had a Bardet-Biedl Syndrome (BBS) gene variant (4 with "pathogenic" or "likely pathogenic" variants). Therefore, 9 youth (7.7%) had gene variants previously identified as increasing risk for obesity and 4 youth (3.4%) had BBS carrier status. CONCLUSIONS Panel testing identified rare variants of uncertain significance in most youth tested, and infrequently identified variants previously reported to increase the risk for obesity. Further research in larger cohorts is needed to understand how genetic variants influence the expression of non-syndromic obesity.
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Affiliation(s)
- Karyn J Roberts
- College of Nursing, University of Wisconsin-Milwaukee, PO Box 413, Milwaukee, WI, 53201-0413, USA. .,Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.
| | - Adolfo J Ariza
- Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.,Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.,Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Kavitha Selvaraj
- Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.,Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Maheen Quadri
- Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.,Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Caren Mangarelli
- Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.,Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Sarah Neault
- Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Erica E Davis
- Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.,Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Helen J Binns
- Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.,Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.,Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
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Enhanced carboxypeptidase efficacies and differentiation of peptide epimers. Anal Biochem 2021; 642:114451. [PMID: 34774536 DOI: 10.1016/j.ab.2021.114451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 10/20/2021] [Accepted: 11/04/2021] [Indexed: 11/24/2022]
Abstract
Carboxypeptidases enzymatically cleaves the peptide bond of C-terminal amino acids within peptides. In humans, it is involved in enzymatic synthesis and maturation of proteins and peptides. Carboxypeptidases A and Y have difficulty hydrolyzing the peptide bond of dipeptides and some other amino acid sequences. Early investigations into different N-blocking groups concluded that larger moieties increased substrate susceptibility to peptide bond hydrolysis with carboxypeptidase. This study conclusively demonstrates that 6-aminoquinoline-N-hydroxysuccimidyl carbamate (AQC) as an N-blocking group greatly enhances substrate hydrolysis with carboxypeptidase. AQC addition to the N-terminus of amino acids and peptides also improves chromatographic peak shape and sensitivities via mass spectrometry detection. These enzymes have been used for amino acid sequence determination prior to the advent of modern proteomics. However, most modern proteomic methods assume that all peptides are comprised of l-amino acids and therefore cannot distinguish L-from d-amino acids within the peptide sequence. The majority of existing methods that allow for chiral differentiation either require synthetic standards or incur racemization in the process. This study highlights the resistance of d-amino acids within peptides to enzymatic hydrolysis by Carboxypeptidase Y. This stereoselectivity may be advantageous when screening low abundance peptide epimers.
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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.
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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
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Lopes‐Marques M, Pacheco AR, Peixoto MJ, Cardoso AR, Serrano C, Amorim A, Prata MJ, Cooper DN, Azevedo L. Common polymorphic OTC variants can act as genetic modifiers of enzymatic activity. Hum Mutat 2021; 42:978-989. [PMID: 34015158 PMCID: PMC8362079 DOI: 10.1002/humu.24221] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 05/05/2021] [Accepted: 05/18/2021] [Indexed: 12/24/2022]
Abstract
Understanding the role of common polymorphisms in modulating the clinical phenotype when they co‐occur with a disease‐causing lesion is of critical importance in medical genetics. We explored the impact of apparently neutral common polymorphisms, using the gene encoding the urea cycle enzyme, ornithine transcarbamylase (OTC), as a model system. Distinct combinations of genetic backgrounds embracing two missense polymorphisms were created in cis with the pathogenic p.Arg40His replacement. In vitro enzymatic assays revealed that the polymorphic variants were able to modulate OTC activity both in the presence or absence of the pathogenic lesion. First, we found that the combination of the minor alleles of polymorphisms p.Lys46Arg and p.Gln270Arg significantly enhanced enzymatic activity in the wild‐type protein. Second, enzymatic assays revealed that the minor allele of the p.Gln270Arg polymorphism was capable of ameliorating OTC activity when combined in cis with the pathogenic p.Arg40His replacement. Structural analysis predicted that the minor allele of the p.Gln270Arg polymorphism would serve to stabilize the OTC wild‐type protein, thereby corroborating the results of the experimental assays. Our findings demonstrate the potential importance of cis‐interactions between common polymorphic variants and pathogenic missense mutations and illustrate how standing genetic variation can modulate protein function.
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Affiliation(s)
- Mónica Lopes‐Marques
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - Ana Rita Pacheco
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
| | - Maria João Peixoto
- ICVS‐ Life and Health Sciences Research Institute, School of MedicineUniversity of MinhoBragaPortugal
- ICVS/3B's‐PT Government Associate LaboratoryBragaGuimarãesPortugal
| | - Ana Rita Cardoso
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - Catarina Serrano
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - António Amorim
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - Maria João Prata
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - David N. Cooper
- Institute of Medical Genetics; School of MedicineCardiff UniversityCardiffUK
| | - Luísa Azevedo
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
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Durmaz A, Aykut A, Atik T, Özen S, Ayyıldız Emecen D, Ata A, Işık E, Gökşen D, Çoğulu Ö, Özkınay F. A New Cause of Obesity Syndrome Associated with a Mutation in the Carboxypeptidase Gene Detected in Three Siblings with Obesity, Intellectual Disability and Hypogonadotropic Hypogonadism. J Clin Res Pediatr Endocrinol 2021; 13:52-60. [PMID: 32936766 PMCID: PMC7947731 DOI: 10.4274/jcrpe.galenos.2020.2020.0101] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Carboxypeptidase E (CPE) plays a critical role in the biosynthesis of peptide hormones and neuropeptides in the endocrine system and central nervous system. CPE knockout mice models exhibit disorders such as diabetes, hyperproinsulinaemia, low bone mineral density and neurodevelopmental disorders. Only one patient is described with morbid obesity, intellectual disability, abnormal glucose homeostasis and hypogonadotropic hypogonadism, which was associated with a homozygous frameshift deletion in CPE. METHODS Herein are described three siblings with obesity, intellectual disability and hypogonadotropic hypogonadism. Whole exome sequencing (WES) was performed in the index case. Candidate variants were prioritised and segregation of the variant, consistent with the phenotype of the index case, was assessed by Sanger sequencing in affected siblings and parents. RESULTS WES analysis revealed a homozygous nonsense c.405C>A (p.Y135*) mutation in CPE. Validation and segregation analysis confirmed the homozygous mutation in the index case and his affected siblings. The parents were phenotypically normal heterozygous mutation carriers. CONCLUSION This study provides additional evidence of the association between a homozygous nonsense mutation in CPE and a clinical phenotype consisting of obesity, intellectual disability and hypogonadotropic hypogonadism, which may be considered as a new monogenic obesity syndrome.
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Affiliation(s)
- Asude Durmaz
- Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey,* Address for Correspondence: Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey E-mail:
| | - Ayça Aykut
- Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey
| | - Tahir Atik
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
| | - Samim Özen
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Endocrinology, İzmir, Turkey
| | - Durdugül Ayyıldız Emecen
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
| | - Aysun Ata
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Endocrinology, İzmir, Turkey
| | - Esra Işık
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
| | - Damla Gökşen
- Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Endocrinology, İzmir, Turkey
| | - Özgür Çoğulu
- Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey,Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
| | - Ferda Özkınay
- Ege University Faculty of Medicine, Department of Medical Genetics, İzmir, Turkey,Ege University Faculty of Medicine, Department of Pediatrics, Subdivision of Pediatric Genetics, İzmir, Turkey
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9
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Vasiljević J, Torkko JM, Knoch KP, Solimena M. The making of insulin in health and disease. Diabetologia 2020; 63:1981-1989. [PMID: 32894308 PMCID: PMC7476993 DOI: 10.1007/s00125-020-05192-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 04/28/2020] [Indexed: 12/16/2022]
Abstract
The discovery of insulin in 1921 has been one of greatest scientific achievements of the 20th century. Since then, the availability of insulin has shifted the focus of diabetes treatment from trying to keep patients alive to saving and improving the life of millions. Throughout this time, basic and clinical research has advanced our understanding of insulin synthesis and action, both in healthy and pathological conditions. Yet, multiple aspects of insulin production remain unknown. In this review, we focus on the most recent findings on insulin synthesis, highlighting their relevance in diabetes. Graphical abstract.
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Affiliation(s)
- Jovana Vasiljević
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
- Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany
| | - Juha M Torkko
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
- Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany
| | - Klaus-Peter Knoch
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
- Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany
| | - Michele Solimena
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany.
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.
- Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany.
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany.
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10
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Parveen A, Mirza MU, Vanmeert M, Akhtar J, Bashir H, Khan S, Shehzad S, Froeyen M, Ahmed W, Ansar M, Wasif N. A novel pathogenic missense variant in CNNM4 underlying Jalili syndrome: Insights from molecular dynamics simulations. Mol Genet Genomic Med 2019; 7:e902. [PMID: 31347285 PMCID: PMC6732295 DOI: 10.1002/mgg3.902] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/04/2019] [Accepted: 07/08/2019] [Indexed: 12/24/2022] Open
Abstract
Background Jalili syndrome (JS) is a rare cone‐rod dystrophy (CRD) associated with amelogenesis imperfecta (AI). The first clinical presentation of JS patients was published in 1988 by Jalili and Smith. Pathogenic mutations in the Cyclin and CBS Domain Divalent Metal Cation Transport Mediator 4 (CNNM4) magnesium transporter protein have been reported as the leading cause of this anomaly. Methods In the present study, a clinical and genetic investigation was performed in a consanguineous family of Pakistani origin, showing characteristic features of JS. Sanger sequencing was successfully used to identify the causative variant in CNNM4. Molecular dynamics (MD) simulations were performed to study the effect of amino acid change over CNNM4 protein. Results Sequence analysis of CNNM4 revealed a novel missense variant (c.1220G>T, p.Arg407Leu) in exon‐1 encoding cystathionine‐β‐synthase (CBS) domain. To comprehend the mutational consequences in the structure, the mutant p.Arg407Leu was modeled together with a previously reported variant (c.1484C>T, p.Thr495Ile) in the same domain. Additionally, docking analysis deciphered the binding mode of the adenosine triphosphate (ATP) cofactor. Furthermore, 60ns MD simulations were carried out on wild type (p.Arg407/p.Thr495) and mutants (p.Arg407Leu/p.Thr495Ile) to understand the structural and energetic changes in protein structure and its dynamic behavior. An evident conformational shift of ATP in the binding site was observed in simulated mutants disrupting the native ATP‐binding mode. Conclusion The novel identified variant in CNNM4 is the first report from the Pakistani population. Overall, the study is valuable and may give a novel insight into metal transport in visual function and biomineralization.
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Affiliation(s)
- Asia Parveen
- Institute of Molecular Biology and Biotechnology (IMBB), Centre for Research in Molecular Medicine (CRiMM), The University of Lahore, Lahore, Pakistan.,Faculty of Life Sciences, University of Central Punjab (UCP), Lahore, Pakistan
| | - Muhammad U Mirza
- Department of Pharmaceutical Sciences, REGA Institute for Medical Research, Medicinal Chemistry, University of Leuven, Leuven, Belgium
| | - Michiel Vanmeert
- Department of Pharmaceutical Sciences, REGA Institute for Medical Research, Medicinal Chemistry, University of Leuven, Leuven, Belgium
| | - Javed Akhtar
- Institute of Molecular Biology and Biotechnology (IMBB), Centre for Research in Molecular Medicine (CRiMM), The University of Lahore, Lahore, Pakistan
| | - Hina Bashir
- Institute of Molecular Biology and Biotechnology (IMBB), Centre for Research in Molecular Medicine (CRiMM), The University of Lahore, Lahore, Pakistan.,Department of Biochemistry, Sharif Medical and Dental College, Lahore, Pakistan
| | - Saadullah Khan
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, Pakistan
| | - Saqib Shehzad
- Faculty of Life Sciences, University of Central Punjab (UCP), Lahore, Pakistan
| | - Matheus Froeyen
- Department of Pharmaceutical Sciences, REGA Institute for Medical Research, Medicinal Chemistry, University of Leuven, Leuven, Belgium
| | - Wasim Ahmed
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Muhammad Ansar
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Naveed Wasif
- Institute of Molecular Biology and Biotechnology (IMBB), Centre for Research in Molecular Medicine (CRiMM), The University of Lahore, Lahore, Pakistan.,Institute of Human Genetics, University of Ulm & University Hospital, Ulm, Germany.,Institute of Human Genetics, University Hospital Schleswig-Holstein, Kiel, Germany
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11
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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.
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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
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12
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Chen YC, Taylor AJ, Verchere CB. Islet prohormone processing in health and disease. Diabetes Obes Metab 2018; 20 Suppl 2:64-76. [PMID: 30230179 DOI: 10.1111/dom.13401] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 05/30/2018] [Accepted: 05/30/2018] [Indexed: 12/15/2022]
Abstract
Biosynthesis of peptide hormones by pancreatic islet endocrine cells is a tightly orchestrated process that is critical for metabolic homeostasis. Like neuroendocrine peptides, insulin and other islet hormones are first synthesized as larger precursor molecules that are processed to their mature secreted products through a series of proteolytic cleavages, mediated by the prohormone convertases Pc1/3 and Pc2, and carboxypeptidase E. Additional posttranslational modifications including C-terminal amidation of the β-cell peptide islet amyloid polypeptide (IAPP) by peptidyl-glycine α-amidating monooxygenase (Pam) may also occur. Genome-wide association studies (GWAS) have showed genetic linkage of these processing enzymes to obesity, β-cell dysfunction, and type 2 diabetes (T2D), pointing to their important roles in metabolism and blood glucose regulation. In both type 1 diabetes (T1D) and T2D, and in the face of metabolic or inflammatory stresses, islet prohormone processing may become impaired; indeed elevated proinsulin:insulin (PI:I) ratios are a hallmark of the β-cell dysfunction in T2D. Recent studies suggest that genetic or acquired defects in proIAPP processing may lead to the production and secretion of incompletely processed forms of proIAPP that could contribute to T2D pathogenesis, and additionally that impaired processing of both PI and proIAPP may be characteristic of β-cell dysfunction in T1D. In islet α-cells, the prohormone proglucagon is normally processed to bioactive glucagon by Pc2 but may express Pc1/3 under certain conditions leading to production of GLP-1(7-36NH2 ). A better understanding of how β-cell processing of PI and proIAPP, as well as α-cell processing of proglucagon, are impacted by genetic susceptibility and in the face of diabetogenic stresses, may lead to new therapeutic approaches for improving islet function in diabetes.
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Affiliation(s)
- Yi-Chun Chen
- Department of Surgery, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
| | - Austin J Taylor
- Department of Surgery, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
| | - C Bruce Verchere
- Department of Surgery, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
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13
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Acosta-Montaño P, García-González V. Effects of Dietary Fatty Acids in Pancreatic Beta Cell Metabolism, Implications in Homeostasis. Nutrients 2018; 10:nu10040393. [PMID: 29565831 PMCID: PMC5946178 DOI: 10.3390/nu10040393] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/02/2018] [Accepted: 03/13/2018] [Indexed: 12/26/2022] Open
Abstract
Fatty acids are involved in several metabolic processes, including the development of metabolic and cardiovascular diseases. In recent years a disease that has received escalated interest is type 2 diabetes (T2D). Many contributing factors including a high-caloric diet rich in dietary saturated fats have been broadly characterized as triggers of T2D. Insulin resistance resulting from a high saturated fat diet leads to alterations in lipid cellular intake and accumulation which generate lipotoxic conditions, a key phenomenon in the metabolism of β-cells. Alternatively, unsaturated fatty acids have been described to show opposite effects in pancreatic β-cells. The purpose of this work is to perform a critical analysis of the complex role of saturated and unsaturated fatty acids in β-cell metabolism. We discuss the diverse effects main dietary fatty acids have upon pancreatic β-cell metabolism as a key factor to maintain homeostasis by focusing in the cellular and molecular mechanisms involved in the development and progression of T2D. For instance, modifications in protein homeostasis as well as the intracellular management of lipid metabolism which are associated with inflammatory pathways. These conditions initiate critical metabolic rearrangements, that in turn have repercussions on insulin β-cell metabolism. This review allows an integral and broad understanding of different functions of fatty acids inside β-cells, being important metabolites for novel therapeutic targets in T2D treatment.
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Affiliation(s)
- Paloma Acosta-Montaño
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico.
| | - Víctor García-González
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico.
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14
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Winters A, Ramos-Molina B, Jarvela TS, Yerges-Armstrong L, Pollin TI, Lindberg I. Functional analysis of PCSK2 coding variants: A founder effect in the Old Order Amish population. Diabetes Res Clin Pract 2017; 131:82-90. [PMID: 28719828 PMCID: PMC5572827 DOI: 10.1016/j.diabres.2017.06.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 02/06/2023]
Abstract
AIMS In humans, noncoding variants of PCSK2, the gene encoding prohormone convertase 2 (PC2), have been previously associated with risk for and age of onset of type 2 diabetes (T2D). The aims of this study were to identify coding variants in PCSK2; to determine their possible association with glucose handling; and to determine functional outcomes for coding variants in biochemical studies. METHODS Exome-wide genotyping was performed on 1725 Old Order Amish (OOA) subjects. PCSK2 coding variants were tested for association with diabetes-related phenotypes. In vitro analyses using transfected human PC2-encoding constructs were performed to determine the impact of each mutation on PC2 activity. RESULTS We identified 10 rare missense coding variants in PCSK2 in various genomic databases. R430W (rs200711626) is greatly enriched in the OOA population (MAF 4.3%). This variant is almost twice as common (MAF 7.4%) in OOA individuals with T2D as in OOA individuals with normal or with normal/impaired glucose tolerance (MAF 3.9% and 2.9%, respectively; p=0.25 and p=0.10). In vitro experiments revealed a broadening of the pH optimum for the R430W variant, which may result in increased activity against PCSK2 substrates. CONCLUSIONS Although the association of the R430W variation with T2D in the OOA population did not reach significance, based upon the broadened pH profile of R430W PC2, we speculate that the presence of this substitution may result in altered processing of PCSK2 substrates, ultimately leading to increased conversion to diabetes.
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Affiliation(s)
- Alexandra Winters
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Bruno Ramos-Molina
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Timothy S Jarvela
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Laura Yerges-Armstrong
- Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Toni I Pollin
- Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States.
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15
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Cong L, Cheng Y, Cawley NX, Murthy SRK, Loh YP. A Novel Single Nucleotide T980C Polymorphism in the Human Carboxypeptidase E Gene Results in Loss of Neuroprotective Function. PLoS One 2017; 12:e0170169. [PMID: 28114332 PMCID: PMC5256889 DOI: 10.1371/journal.pone.0170169] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 12/30/2016] [Indexed: 11/18/2022] Open
Abstract
Report of a human with a homozygous truncating null mutation of the Carboxypeptidase E (CPE) gene with endocrinological and neurological deficits prompted us to search for other mutations in the human CPE gene that might be linked to disease. We searched an EST database and identified from a small population of patients, a novel T to C single nucleotide polymorphism (SNP) in the CPE gene at bp980 of exon 4, herein called TC-CPE. This introduces a tryptophan to arginine (W235R) mutation in the catalytic domain of human CPE protein. Over-expression of TC-CPE in N2A cells, a neuroendocrine cell line, showed that it was synthesized, but was found in lesser amounts compared to over-expressed WT-CPE in these cells. Furthermore, TC-CPE was secreted poorly from these N2A cells. The levels of TC-CPE were significantly increased after the N2A cells were treated with MG132 (a proteasome inhibitor), suggesting that TC-CPE was targeted to proteasomes for degradation in N2A cells. In addition, TC-CPE induced ER stress as demonstrated by the increased expression of CHOP in N2A cells. Double labeling of CPE and calnexin (and ER marker) suggested the accumulation of TC-CPE in the ER, and the accumulation appears to be enhanced by the treatment of MG132 in the cells. Moreover, the secreted levels of TC-CPE were not affected by the treatment of MG132 in the cells. Over-expression studies revealed that while N2A cells transfected with WT-CPE showed reduced cytotoxicity when challenged with H2O2 compared to cells expressing an empty vector, cells transfected with TC-CPE had no effect. Furthermore, WT-CPE condition medium showed protective effect against oxidative stress, but not TC-CPE condition medium. Although co-expression of WT-CPE and TC-CPE in N2A cells resulted in the reduction in secretion of WT-CPE, co-expression of WT-CPE and TC-CPE did not significantly affect the protective effect of WT-CPE. Taken together, we have identified a novel SNP in the CPE gene which results in the loss of its neuroprotective function in cells and may confer neurological disorders in humans.
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Affiliation(s)
- Lin Cong
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Yong Cheng
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Niamh X. Cawley
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Saravana R. K. Murthy
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Y. Peng Loh
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
- * E-mail:
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16
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Sun J, Meng D, Li L, Tian X, Jia Y, Wang H, Yu H, Sun T, Qu A, Shen H, Bao J, Zhang G. N-terminal truncated carboxypeptidase E expression is associated with poor prognosis of lung adenocarcinoma. Oncol Lett 2016; 12:4659-4664. [PMID: 28101219 DOI: 10.3892/ol.2016.5283] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 08/09/2016] [Indexed: 01/23/2023] Open
Abstract
Lung cancer is a malignant tumor with high morbidity and mortality rates. To date, no suitable molecular diagnostic tool to predict disease recurrence and metastasis has been identified. The current study aimed to evaluate the potential of N-terminal truncated carboxypeptidase E (CPEΔN) to predict the recurrence and metastasis of lung adenocarcinoma. Western blotting revealed the co-expression of CPE and CPEΔN in the surgically collected pathological and pericarcinoma tissues tissues of 62.1% (59/95) lung adenocarcinoma patients. The full length CPE protein was predominantly expressed in pericarcinoma tissues and CPEΔN expression was identified in the pericarcinoma normal tissues of only 5.26% (5/95) patients. The 3-year postoperative recurrence and metastasis rates were significantly higher in patients with positive CPEΔN expression than in patients with negative CPEΔN expression (P=0.009). Furthermore, the overall survival rate of patients with predominant nuclear CPE expression was lower than that of patients with predominant cytoplasmic CPE expression (46.3 vs. 64.7%); however, no statistically significant difference was identified (P=0.125). Thus, the results of the current study indicated that CPEΔN may present a novel molecular biomarker for predicting recurrence and metastasis of lung adenocarcinoma, which may aid with stratifying patients by risk and thus, may facilitate individualized therapy.
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Affiliation(s)
- Jing Sun
- Cancer Hospital of China Medical University, Shenyang, Liaoning 110042, P.R. China; Liaoning Cancer Hospital and Institute, Shenyang, Liaoning 110042, P.R. China
| | - Dawei Meng
- Department of Otolaryngology-Head and Neck Surgery, Jinqiu Hospital of Liaoning Province, Shenyang, Liaoning 110016, P.R. China
| | - Li Li
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, P.R. China
| | - Xin Tian
- Molecular Oncology Laboratory, Cancer Research Institute, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yunji Jia
- Department of General Surgery, Central Hospital Affiliated to Shenyang Medical College, Shenyang, Liaoning 110024, P.R. China
| | - Hongyue Wang
- Cancer Hospital of China Medical University, Shenyang, Liaoning 110042, P.R. China; Liaoning Cancer Hospital and Institute, Shenyang, Liaoning 110042, P.R. China
| | - Huihui Yu
- Department of Epidemiology, Liaoning Cancer Hospital and Institute, Shenyang, Liaoning 110042, P.R. China
| | - Tiemin Sun
- Cancer Hospital of China Medical University, Shenyang, Liaoning 110042, P.R. China; Liaoning Cancer Hospital and Institute, Shenyang, Liaoning 110042, P.R. China
| | - Aibing Qu
- Cancer Hospital of China Medical University, Shenyang, Liaoning 110042, P.R. China; Liaoning Cancer Hospital and Institute, Shenyang, Liaoning 110042, P.R. China
| | - Hui Shen
- Cancer Hospital of China Medical University, Shenyang, Liaoning 110042, P.R. China; Liaoning Cancer Hospital and Institute, Shenyang, Liaoning 110042, P.R. China
| | - Jimin Bao
- Department of Otolaryngology-Head and Neck Surgery, Jinqiu Hospital of Liaoning Province, Shenyang, Liaoning 110016, P.R. China
| | - Guirong Zhang
- Cancer Hospital of China Medical University, Shenyang, Liaoning 110042, P.R. China; Liaoning Cancer Hospital and Institute, Shenyang, Liaoning 110042, P.R. China
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Valente TS, Baldi F, Sant’Anna AC, Albuquerque LG, Paranhos da Costa MJR. Genome-Wide Association Study between Single Nucleotide Polymorphisms and Flight Speed in Nellore Cattle. PLoS One 2016; 11:e0156956. [PMID: 27300296 PMCID: PMC4907449 DOI: 10.1371/journal.pone.0156956] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/23/2016] [Indexed: 12/17/2022] Open
Abstract
Introduction Cattle temperament is an important factor that affects the profitability of beef cattle enterprises, due to its relationship with productivity traits, animal welfare and labor safety. Temperament is a complex phenotype often assessed by measuring a series of behavioral traits, which result from the effects of multiple environmental and genetic factors, and their interactions. The aims of this study were to perform a genome-wide association study and detect genomic regions, potential candidate genes and their biological mechanisms underlying temperament, measured by flight speed (FS) test in Nellore cattle. Materials and Methods The genome-wide association study (GWAS) was performed using a single-step procedure (ssGBLUP) which combined simultaneously all 16,600 phenotypes from genotyped and non-genotyped animals, full pedigree information of 162,645 animals and 1,384 genotyped animals in one step. The animals were genotyped with High Density Bovine SNP BeadChip which contains 777,962 SNP markers. After quality control (QC) a total of 455,374 SNPs remained. Results Heritability estimated for FS was 0.21 ± 0.02. Consecutive SNPs explaining 1% or more of the total additive genetic variance were considered as windows associated with FS. Nine candidate regions located on eight different Bos taurus chromosomes (BTA) (1 at 73 Mb, 2 at 65 Mb, 5 at 22 Mb and 119 Mb, 9 at 98 Mb, 11 at 67 Mb, 15 at 16 Mb, 17 at 63 Kb, and 26 at 47 Mb) were identified. The candidate genes identified in these regions were NCKAP5 (BTA2), PARK2 (BTA9), ANTXR1 (BTA11), GUCY1A2 (BTA15), CPE (BTA17) and DOCK1 (BTA26). Among these genes PARK2, GUCY1A2, CPE and DOCK1 are related to dopaminergic system, memory formation, biosynthesis of peptide hormone and neurotransmitter and brain development, respectively. Conclusions Our findings allowed us to identify nine genomic regions (SNP windows) associated with beef cattle temperament, measured by FS test. Within these windows, six promising candidate genes and their biological functions were identified. These results may contribute to a better comprehension into the genetic control of temperament expression in Nellore cattle.
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Affiliation(s)
- Tiago Silva Valente
- Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Departamento de Zootecnia, Via de Acesso Professor Paulo Donato Castellane, Jaboticabal, SP 14.884-900, Brazil
| | - Fernando Baldi
- Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Departamento de Zootecnia, Via de Acesso Professor Paulo Donato Castellane, Jaboticabal, SP 14.884-900, Brazil
| | - Aline Cristina Sant’Anna
- Universidade Federal de Juiz de Fora (UFJF), Instituto de Ciências Biológicas, Departamento de Zoologia, Rua José Lourenço Kelmer, Juiz de Fora, MG 36.036-900, Brazil
| | - Lucia Galvão Albuquerque
- Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Departamento de Zootecnia, Via de Acesso Professor Paulo Donato Castellane, Jaboticabal, SP 14.884-900, Brazil
| | - Mateus José Rodrigues Paranhos da Costa
- Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Departamento de Zootecnia, Via de Acesso Professor Paulo Donato Castellane, Jaboticabal, SP 14.884-900, Brazil
- * E-mail:
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Biological findings from the PheWAS catalog: focus on connective tissue-related disorders (pelvic floor dysfunction, abdominal hernia, varicose veins and hemorrhoids). Hum Genet 2016; 135:779-95. [DOI: 10.1007/s00439-016-1672-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 04/17/2016] [Indexed: 01/31/2023]
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19
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Giri A, Wu JM, Ward RM, Hartmann KE, Park AJ, North KE, Graff M, Wallace RB, Bareh G, Qi L, O'Sullivan MJ, Reiner AP, Edwards TL, Velez Edwards DR. Genetic Determinants of Pelvic Organ Prolapse among African American and Hispanic Women in the Women's Health Initiative. PLoS One 2015; 10:e0141647. [PMID: 26545240 PMCID: PMC4636147 DOI: 10.1371/journal.pone.0141647] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/12/2015] [Indexed: 12/14/2022] Open
Abstract
Current evidence suggests a multifactorial etiology to pelvic organ prolapse (POP), including genetic predisposition. We conducted a genome-wide association study of POP in African American (AA) and Hispanic (HP) women from the Women's Health Initiative Hormone Therapy study. Cases were defined as any POP (grades 1-3) or moderate/severe POP (grades 2-3), while controls had grade 0 POP. We performed race-specific multiple logistic regression analyses between SNPs imputed to 1000 genomes in relation to POP (grade 0 vs 1-3; grade 0 vs 2-3) adjusting for age at diagnosis, body mass index, parity, and genetic ancestry. There were 1274 controls and 1427 cases of any POP and 317 cases of moderate/severe POP. Although none of the analyses reached genome-wide significance (p<5x10-8), we noted variants in several loci that met p<10-6. In race-specific analysis of grade 0 vs 2-3, intronic SNPs in the CPE gene (rs28573326, OR:2.14; 95% CI 1.62-2.83; p = 1.0x10-7) were associated with POP in AAs, and SNPs in the gene AL132709.5 (rs1950626, OR:2.96; 95% CI 1.96-4.48, p = 2.6x10-7) were associated with POP in HPs. Inverse variance fixed-effect meta-analysis of the race-specific results showed suggestive signals for SNPs in the DPP6 gene (rs11243354, OR:1.36; p = 4.2x10-7) in the grade 0 vs 1-3 analyses and for SNPs around PGBD5 (rs740494, OR:2.17; p = 8.6x10-7) and SHC3 (rs2209875, OR:0.60; p = 9.3x10-7) in the grade 0 vs 2-3 analyses. While we did not identify genome-wide significant findings, we document several SNPs reaching suggestive statistical significance. Further interrogation of POP in larger minority samples is warranted.
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Affiliation(s)
- Ayush Giri
- Institute for Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Jennifer M. Wu
- Department of Obstetrics and Gynecology, Center for Women’s Health Research, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Renee M. Ward
- Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Katherine E. Hartmann
- Institute for Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Amy J. Park
- Department of Obstetrics and Gynecology and Urology, Georgetown University Medical Center, Washington, DC, United States of America
| | - Kari E. North
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Mariaelisa Graff
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Robert B. Wallace
- Department of Epidemiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Gihan Bareh
- Department of Obstetrics and Gynecology, Loma Linda University, Loma Linda, California, United States of America
| | - Lihong Qi
- Department of Public Health Sciences, University of California, Davis, California, United States of America
| | - Mary J. O'Sullivan
- Department of Obstetrics and Gynecology, University of Miami, Miami, Florida, United States of America
| | - Alexander P. Reiner
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - Todd L. Edwards
- Institute for Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Digna R. Velez Edwards
- Institute for Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, Tennessee, United States of America
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Alsters SIM, Goldstone AP, Buxton JL, Zekavati A, Sosinsky A, Yiorkas AM, Holder S, Klaber RE, Bridges N, van Haelst MM, le Roux CW, Walley AJ, Walters RG, Mueller M, Blakemore AIF. Truncating Homozygous Mutation of Carboxypeptidase E (CPE) in a Morbidly Obese Female with Type 2 Diabetes Mellitus, Intellectual Disability and Hypogonadotrophic Hypogonadism. PLoS One 2015; 10:e0131417. [PMID: 26120850 PMCID: PMC4485893 DOI: 10.1371/journal.pone.0131417] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 06/02/2015] [Indexed: 01/25/2023] Open
Abstract
Carboxypeptidase E is a peptide processing enzyme, involved in cleaving numerous peptide precursors, including neuropeptides and hormones involved in appetite control and glucose metabolism. Exome sequencing of a morbidly obese female from a consanguineous family revealed homozygosity for a truncating mutation of the CPE gene (c.76_98del; p.E26RfsX68). Analysis detected no CPE expression in whole blood-derived RNA from the proband, consistent with nonsense-mediated decay. The morbid obesity, intellectual disability, abnormal glucose homeostasis and hypogonadotrophic hypogonadism seen in this individual recapitulates phenotypes in the previously described fat/fat and Cpe knockout mouse models, evidencing the importance of this peptide/hormone-processing enzyme in regulating body weight, metabolism, and brain and reproductive function in humans.
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Affiliation(s)
- Suzanne I. M. Alsters
- Section of Investigative Medicine, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | - Anthony P. Goldstone
- Imperial Centre for Endocrinology, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London, United Kingdom
- Centre for Neuropsychopharmacology and Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
- Metabolic and Molecular Imaging Group, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, London, United Kingdom
- * E-mail: (AG); (AB)
| | - Jessica L. Buxton
- Section of Investigative Medicine, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
- Centre for Cardiovascular Genetics, UCL Institute of Cardiovascular Science, London, United Kingdom
| | - Anna Zekavati
- NIHR Imperial BRC Genomics Facility, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Alona Sosinsky
- NIHR Imperial BRC Genomics Facility, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Andrianos M. Yiorkas
- Section of Investigative Medicine, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | - Susan Holder
- NW Thames Regional Genetics Service, Kennedy Galton Centre, North West London Hospitals NHS Trust, Northwick Park Hospital, Harrow, United Kingdom
| | - Robert E. Klaber
- Department of Paediatrics, Imperial College Healthcare NHS Trust, St Mary's Hospital, London, United Kingdom
| | - Nicola Bridges
- Department of Paediatric Endocrinology, Chelsea and Westminster Hospital, London, United Kingdom
| | - Mieke M. van Haelst
- Department of Medical Genetics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Carel W. le Roux
- Section of Investigative Medicine, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
- Diabetes Complications Research Centre, Conway Institute, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Andrew J. Walley
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, United Kingdom
| | - Robin G. Walters
- Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
| | - Michael Mueller
- NIHR Imperial BRC Genomics Facility, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Alexandra I. F. Blakemore
- Section of Investigative Medicine, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
- * E-mail: (AG); (AB)
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Sun J, Zhang G, Wang H, Shen H. [Screening of Highly Expressed CPEΔN Lung Cancer H1299 Cells]. ZHONGGUO FEI AI ZA ZHI = CHINESE JOURNAL OF LUNG CANCER 2015; 18:340-4. [PMID: 26104889 PMCID: PMC5999908 DOI: 10.3779/j.issn.1009-3419.2015.06.03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
背景与目的 N端截短的羧肽酶E(N-terminal truncated carboxypeptidase E, CPEΔN)是一个新的肿瘤转移相关蛋白。本研究旨在筛选高表达CPEΔN的H1299肺癌细胞株,为完成小鼠活体成像实验创造条件。 方法 构建CPEΔN的慢病毒表达载体。分别用CPEΔN慢病毒表达载体或对照慢病毒空载体转染H1299细胞,2 μg/mL的嘌呤霉素加压筛选。Western blot分析CPEΔN蛋白的表达,荧光素酶报告基因实验分析荧光素酶对底物的分解作用。 结果 当感染倍数(multiple of infection, MOI)是20时,慢病毒对H1299细胞的转染效率可以达到80%。CPEΔN高表达H1299细胞株(H1299-CPEΔN)和对照慢病毒载体表达H1299细胞株(H1299-control)中CPEΔN蛋白的表达量为4:1。H1299-CPEΔN和H1299-control均能够有效分解荧光素酶底物,可以满足活体成像实验的需求。 结论 筛选出高表达CPEΔN的H1299肺癌细胞株,为活体成像实验的开展创造了条件,也为进一步解释CPEΔN促进肿瘤转移的分子机制奠定了基础。
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Affiliation(s)
- Jing Sun
- Biotherapy Research Center, Liaoning Cancer Hospital and Institute, Shenyang 110042, China
| | - Guirong Zhang
- Biotherapy Research Center, Liaoning Cancer Hospital and Institute, Shenyang 110042, China
| | - Hongyue Wang
- Biotherapy Research Center, Liaoning Cancer Hospital and Institute, Shenyang 110042, China
| | - Hui Shen
- Biotherapy Research Center, Liaoning Cancer Hospital and Institute, Shenyang 110042, China
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22
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Sapio MR, Fricker LD. Carboxypeptidases in disease: insights from peptidomic studies. Proteomics Clin Appl 2014; 8:327-37. [PMID: 24470285 DOI: 10.1002/prca.201300090] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/10/2013] [Accepted: 10/30/2013] [Indexed: 12/19/2022]
Abstract
Carboxypeptidases (CPs) perform many diverse physiological functions by removing C-terminal amino acids from proteins and peptides. Some CPs function in the degradation of proteins in the digestive tract while other enzymes play biosynthetic roles in the formation of neuropeptides and peptide hormones. Another set of CPs modify tubulin by removing amino acids from the C-terminus and from polyglutamyl side chains, thereby altering the properties of microtubules. This review focuses on three CPs: carboxypeptidase E, carboxypeptidase A6, and cytosolic carboxypeptidase 1. Naturally occurring mutations in all three of these enzymes are associated with disease phenotypes, ranging from obesity to epilepsy to neurodegeneration. Peptidomics is a useful tool to investigate the relationship between these mutations and alterations in peptide levels. This technique has also been used to define the function and characteristics of CPs. Results from peptidomics studies have helped to elucidate the function of CPs and clarify the biological underpinnings of pathologies by identifying peptides altered in disease states. This review describes the use of peptidomic techniques to gain insights into the normal function of CPs and the molecular defects caused by mutations in the enzymes.
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Affiliation(s)
- Matthew R Sapio
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
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23
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Ribeca C, Bonfatti V, Cecchinato A, Albera A, Gallo L, Carnier P. Effect of polymorphisms in candidate genes on carcass and meat quality traits in double muscled Piemontese cattle. Meat Sci 2013; 96:1376-83. [PMID: 24361557 DOI: 10.1016/j.meatsci.2013.11.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/25/2013] [Accepted: 11/26/2013] [Indexed: 11/27/2022]
Abstract
The aim of this study was to investigate the association between 10 candidate genes and carcass weight and conformation, carcass daily gain, and meat quality (pH, color, cooking loss, drip loss and shear force) in 990 double-muscled Piemontese young bulls. Animals were genotyped at each of the following genes: growth hormone, growth hormone receptor, pro-opiomelanocortin, pro-opiomelanocortin class 1 homeobox 1, melanocortin-4 receptor, corticotrophin-releasing hormone, diacylglycerol O-acyltransferase-1, thyroglobulin, carboxypeptidase E and gamma-3 regulatory subunit of the AMP-activated protein kinase. All the investigated SNPs had additive effects which were relevant for at least one of the traits. Relevant associations between the investigated SNPs and carcass weight, carcass daily gain and carcass conformation were detected, whereas associations of SNPs with meat quality were moderate. Results confirmed some of previously reported associations, but diverged for others. Validation in other cattle breeds is required to use these SNPs in gene-assisted selection programs for enhancement of carcass traits and meat quality.
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Affiliation(s)
- C Ribeca
- Department of Agriculture, Food, Natural Resources, Animals and Environment, University of Padova, Viale dell'Università 16, 35020, Legnaro, Padova, Italy
| | - V Bonfatti
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università 16, 35020, Legnaro, Padova, Italy.
| | - A Cecchinato
- Department of Agriculture, Food, Natural Resources, Animals and Environment, University of Padova, Viale dell'Università 16, 35020, Legnaro, Padova, Italy
| | - A Albera
- Piemontese Cattle Breeders Association (ANABoRaPi), strada Trinità 32/a, Carrù, 12061, Italy
| | - L Gallo
- Department of Agriculture, Food, Natural Resources, Animals and Environment, University of Padova, Viale dell'Università 16, 35020, Legnaro, Padova, Italy
| | - P Carnier
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università 16, 35020, Legnaro, Padova, Italy
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24
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Liang XH, Li LL, Wu GG, Xie YC, Zhang GX, Chen W, Yang HF, Liu QL, Li WH, He WG, Huang YN, Zeng XC. Upregulation of CPE promotes cell proliferation and tumorigenicity in colorectal cancer. BMC Cancer 2013; 13:412. [PMID: 24006921 PMCID: PMC3844403 DOI: 10.1186/1471-2407-13-412] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 08/30/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Colorectal cancer (CRC) is one of the most common cancers worldwide and a leading cause of cancer related death. Although the mortality rate of CRC is decreasing, finding novel targets for its therapy remains urgent. Carboxypeptidase E (CPE), a member of the pro-protein convertases, which are involved in the maturation of protein precursors, has recently been reported as elevated in many types of cancer. However, its role and mechanisms in tumor progression are poorly understood. METHODS In the present study, we investigated expression of CPE in CRC cell lines and tumor tissues using Western blot and real-time qRT-PCR. Plasmids for overexpression and depletion of CPE were constructed and analyzed by Western blot, MTT and colony formation assays and bromodeoxyuridine incorporation assays. The relative expression of p21, p27, and cyclin D1 were analyzed by Real-time qRT-PCR in the indicated cells. RESULTS Our study showed that CPE was significantly upregulated in CRC cell lines and tumor tissues. MTT and colony formation assays indicated that overexpression of CPE enhanced cell growth rates. BrdU incorporation and flow-cytometry assays showed that ectopic expression of CPE increased the S-phase fraction cells. Soft agar assay proved enhanced tumorigenicity activity in CPE over-expressing CRC cells. Further studies of the molecular mechanisms of CPE indicated that is promoted cell proliferation and tumorigenicity through downregulation of p21 and p27, and upregulation of cyclin D1. CONCLUSIONS Taken together, these data suggest that CPE plays an important role in cell cycle regulation and tumorigenicity, and may serve as a potential target for CRC therapeutics.
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Affiliation(s)
- Xing-Hua Liang
- Department of General Surgery, Zengcheng People's Hospital, (BoJi-Affiliated Hospital of Sun Yat-Sen University), Zengcheng 511300, China.
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25
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Overexpression of CPE-ΔN predicts poor prognosis in colorectal cancer patients. Tumour Biol 2013; 34:3691-9. [PMID: 23852859 DOI: 10.1007/s13277-013-0952-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 06/17/2013] [Indexed: 10/26/2022] Open
Abstract
Carboxypeptidase E (CPE) is one of the most important carboxypeptidases involved in biosynthesis of numerous peptide hormones and neurotransmitters and has an important role in endocrine regulation. A splice variant of CPE (CPE-ΔN) has been detected and the mechanism of CPE-ΔN action in tumorigenesis has been studied in many different cancers. The aim of this study was to examine CPE-ΔN expression in human colorectal cancer (CRC) and to evaluate its possible use as a potential prognostic marker. Two hundred nineteen primary colorectal tumors and corresponding normal tissues were included in the study. We have analyzed CPE-ΔN isoform expression by qRT-PCR and Western blot in 219 CRC patients. Correlations between CPE-ΔN mRNA expression and clinicopathological variables were determined with chi-square tests. Survival probabilities were determined using Kaplan-Meier analysis, and univariate and multivariate analyses of the prognostic factors were performed with a Cox regression model. Our results show that CPE-ΔN is overexpressed in colorectal tumor tissue and that high CPE-ΔN mRNA expression is closely correlated with tumor differentiation, pT classification, pN classification, tumor recurrence, and lymph node metastasis (P = 0.042, 0.036, 0.031, 0.006, and 0.008, respectively). However, no correlation was observed between CPE-ΔN expression and age, gender, tumor localization, gross features, and the tumor size. In addition, patients with high CPE-ΔN expression had a significantly shorter survival (P < 0.001, logrank test). Tumor differentiation, gross feature, pT classification, pN classification, tumor recurrence, lymph node metastasis, and CPE-ΔN status were significantly associated with poor prognosis after performing a univariate Cox survival analysis. High CPE-ΔN expression was also identified as an independent prognostic factor using a multivariate analysis (P = 0.011). Based on these results, we can conclude that CPE-ΔN expression might be a potential prognostic marker for colorectal cancer patients.
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26
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Lam VKL, Ma RCW, Lee HM, Hu C, Park KS, Furuta H, Wang Y, Tam CHT, Sim X, Ng DPK, Liu J, Wong TY, Tai ES, Morris AP, Tang NLS, Woo J, Leung PC, Kong APS, Ozaki R, Jia WP, Lee HK, Nanjo K, Xu G, Ng MCY, So WY, Chan JCN. Genetic associations of type 2 diabetes with islet amyloid polypeptide processing and degrading pathways in asian populations. PLoS One 2013; 8:e62378. [PMID: 23776430 PMCID: PMC3679113 DOI: 10.1371/journal.pone.0062378] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Accepted: 03/21/2013] [Indexed: 01/09/2023] Open
Abstract
Type 2 diabetes (T2D) is a complex disease characterized by beta cell dysfunctions. Islet amyloid polypeptide (IAPP) is highly conserved and co-secreted with insulin with over 40% of autopsy cases of T2D showing islet amyloid formation due to IAPP aggregation. Dysregulation in IAPP processing, stabilization and degradation can cause excessive oligomerization with beta cell toxicity. Previous studies examining genetic associations of pathways implicated in IAPP metabolism have yielded conflicting results due to small sample size, insufficient interrogation of gene structure and gene-gene interactions. In this multi-staged study, we screened 89 tag single nucleotide polymorphisms (SNPs) in 6 candidate genes implicated in IAPP metabolism and tested for independent and joint associations with T2D and beta cell dysfunctions. Positive signals in the stage-1 were confirmed by de novo and in silico analysis in a multi-centre unrelated case-control cohort. We examined the association of significant SNPs with quantitative traits in a subset of controls and performed bioinformatics and relevant functional analyses. Amongst the tag SNPs, rs1583645 in carboxypeptidase E (CPE) and rs6583813 in insulin degrading enzyme (IDE) were associated with 1.09 to 1.28 fold increased risk of T2D (PMeta = 9.4×10−3 and 0.02 respectively) in a meta-analysis of East Asians. Using genetic risk scores (GRS) with each risk variant scoring 1, subjects with GRS≥3 (8.2% of the cohort) had 56% higher risk of T2D than those with GRS = 0 (P = 0.01). In a subcohort of control subjects, plasma IAPP increased and beta cell function index declined with GRS (P = 0.008 and 0.03 respectively). Bioinformatics and functional analyses of CPE rs1583645 predicted regulatory elements for chromatin modification and transcription factors, suggesting differential DNA-protein interactions and gene expression. Taken together, these results support the importance of dysregulation of IAPP metabolism in T2D in East Asians.
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Affiliation(s)
- Vincent Kwok Lim Lam
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Ronald Ching Wan Ma
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
- Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China
- Li Ka Shing Institute of Health, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Heung Man Lee
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Cheng Hu
- Department of Endocrinology and Metabolism, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Clinical Center for Diabetes, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, People's Republic of China
| | - Kyong Soo Park
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology and Department of Internal Medicine, College of Medicine, Seoul National University, Chongno-gu, Seoul, Korea
| | - Hiroto Furuta
- First Department of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Ying Wang
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Claudia Ha Ting Tam
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Xueling Sim
- Centre for Molecular Epidemiology, Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Daniel Peng-Keat Ng
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Jianjun Liu
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Tien-Yin Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - E. Shyong Tai
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Duke-National University of Singapore Graduate Medical School, Singapore, Singapore
| | - Andrew P. Morris
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Nelson Leung Sang Tang
- Department of Chemical Pathology, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Jean Woo
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Ping Chung Leung
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Alice Pik Shan Kong
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Risa Ozaki
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Wei Ping Jia
- Department of Endocrinology and Metabolism, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Clinical Center for Diabetes, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, People's Republic of China
| | - Hong Kyu Lee
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology and Department of Internal Medicine, College of Medicine, Seoul National University, Chongno-gu, Seoul, Korea
| | - Kishio Nanjo
- First Department of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Gang Xu
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
- Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China
- Li Ka Shing Institute of Health, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Maggie Chor Yin Ng
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Wing-Yee So
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
| | - Juliana Chung Ngor Chan
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
- Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China
- Li Ka Shing Institute of Health, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China
- * E-mail:
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Tanco S, Lorenzo J, Garcia-Pardo J, Degroeve S, Martens L, Aviles FX, Gevaert K, Van Damme P. Proteome-derived peptide libraries to study the substrate specificity profiles of carboxypeptidases. Mol Cell Proteomics 2013; 12:2096-110. [PMID: 23620545 DOI: 10.1074/mcp.m112.023234] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Through processing peptide and protein C termini, carboxypeptidases participate in the regulation of various biological processes. Few tools are however available to study the substrate specificity profiles of these enzymes. We developed a proteome-derived peptide library approach to study the substrate preferences of carboxypeptidases. Our COFRADIC-based approach takes advantage of the distinct chromatographic behavior of intact peptides and the proteolytic products generated by the action of carboxypeptidases, to enrich the latter and facilitate its MS-based identification. Two different peptide libraries, generated either by chymotrypsin or by metalloendopeptidase Lys-N, were used to determine the substrate preferences of human metallocarboxypeptidases A1 (hCPA1), A2 (hCPA2), and A4 (hCPA4). In addition, our approach allowed us to delineate the substrate specificity profile of mouse mast cell carboxypeptidase (MC-CPA or mCPA3), a carboxypeptidase suggested to function in innate immune responses regulation and mast cell granule homeostasis, but which thus far lacked a detailed analysis of its substrate preferences. mCPA3 was here shown to preferentially remove bulky aromatic amino acids, similar to hCPA2. This was also shown by a hierarchical cluster analysis, grouping hCPA1 close to hCPA4 in terms of its P1 primed substrate specificity, whereas hCPA2 and mCPA3 cluster separately. The specificity profile of mCPA3 may further aid to elucidate the function of this mast cell carboxypeptidase and its biological substrate repertoire. Finally, we used this approach to evaluate the substrate preferences of prolylcarboxypeptidase, a serine carboxypeptidase shown to cleave C-terminal amino acids linked to proline and alanine.
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Affiliation(s)
- Sebastian Tanco
- Institut de Biotecnologia i de Biomedicina and Departament de Bioquímica i de Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
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George Priya Doss C, Nagasundaram N, Chakraborty C, Chen L, Zhu H. Extrapolating the effect of deleterious nsSNPs in the binding adaptability of flavopiridol with CDK7 protein: a molecular dynamics approach. Hum Genomics 2013; 7:10. [PMID: 23561625 PMCID: PMC3726351 DOI: 10.1186/1479-7364-7-10] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Accepted: 02/18/2013] [Indexed: 11/22/2022] Open
Abstract
Background Recent reports suggest the role of nonsynonymous single nucleotide polymorphisms (nsSNPs) in cyclin-dependent kinase 7 (CDK7) gene associated with defect in the DNA repair mechanism that may contribute to cancer risk. Among the various inhibitors developed so far, flavopiridol proved to be a potential antitumor drug in the phase-III clinical trial for chronic lymphocytic leukemia. Here, we described a theoretical assessment for the discovery of new drugs or drug targets in CDK7 protein owing to the changes caused by deleterious nsSNPs. Methods Three nsSNPs (I63R, H135R, and T285M) were predicted to have functional impact on protein function by SIFT, PolyPhen2, I-Mutant3, PANTHER, SNPs&GO, PhD-SNP, and screening for non-acceptable polymorphisms (SNAP). Furthermore, we analyzed the native and proposed mutant models in atomic level 10 ns simulation using the molecular dynamics (MD) approach. Finally, with the aid of Autodock 4.0 and PatchDock, we analyzed the binding efficacy of flavopiridol with CDK7 protein with respect to the deleterious mutations. Results By comparing the results of all seven prediction tools, three nsSNPs (I63R, H135R, and T285M) were predicted to have functional impact on the protein function. The results of protein stability analysis inferred that I63R and H135R exhibited less deviation in root mean square deviation in comparison with the native and T285M protein. The flexibility of all the three mutant models of CDK7 protein is diverse in comparison with the native protein. Following to that, docking study revealed the change in the active site residues and decrease in the binding affinity of flavopiridol with mutant proteins. Conclusion This theoretical approach is entirely based on computational methods, which has the ability to identify the disease-related SNPs in complex disorders by contrasting their costs and capabilities with those of the experimental methods. The identification of disease related SNPs by computational methods has the potential to create personalized tools for the diagnosis, prognosis, and treatment of diseases. Lay abstract Cell cycle regulatory protein, CDK7, is linked with DNA repair mechanism which can contribute to cancer risk. The main aim of this study is to extrapolate the relationship between the nsSNPs and their effects in drug-binding capability. In this work, we propose a new methodology which (1) efficiently identified the deleterious nsSNPs that tend to have functional effect on protein function upon mutation by computational tools, (2) analyze d the native protein and proposed mutant models in atomic level using MD approach, and (3) investigated the protein-ligand interactions to analyze the binding ability by docking analysis. This theoretical approach is entirely based on computational methods, which has the ability to identify the disease-related SNPs in complex disorders by contrasting their costs and capabilities with those of the experimental methods. Overall, this approach has the potential to create personalized tools for the diagnosis, prognosis, and treatment of diseases.
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Affiliation(s)
- C George Priya Doss
- Medical Biotechnology Division, Centre for Nanobiotechnology, School of Biosciences and Technology, VIT University, Vellore 632014, Tamil Nadu 632014, India.
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Rowzee AM, Perez-Riveros PJ, Zheng C, Krygowski S, Baum BJ, Cawley NX. Expression and secretion of human proinsulin-B10 from mouse salivary glands: implications for the treatment of type I diabetes mellitus. PLoS One 2013; 8:e59222. [PMID: 23554999 PMCID: PMC3598661 DOI: 10.1371/journal.pone.0059222] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 02/12/2013] [Indexed: 12/29/2022] Open
Abstract
Adenovirus (Ad) mediated expression of therapeutic proteins from salivary glands can result in the delivery of biologically active proteins into the circulation where they impart their physiological function. In recent years, Ad vector delivery to salivary glands (SGs) has emerged as a viable option for gene therapy. Here, we engineered a variant of human proinsulin (hProinsulin-B10) into an Ad vector and demonstrated its ability to transduce cell lines, and express a bioactive protein that induces the phosphorylation of AKT, a key insulin signaling molecule. We also examined its expression in mice following delivery of the vector to the parotid gland (PTG), the submandibular gland (SMG) or to the liver via the tail vein and assessed transgenic protein expression and vector containment for each delivery method. In all cases, hProinsulin-B10 was expressed and secreted into the circulation. Lower levels of circulating hProinsulin-B10 were obtained from the PTG while higher levels were obtained from the tail vein and the SMG; however, vector particle containment was best when delivered to the SMG. Expression of hProinsulin-B10 in the SMG of chemically induced diabetic mice prevented excessive hyperglycemia observed in untreated mice. These results demonstrate that hProinsulin-B10 can be expressed and secreted into the circulation from SGs and can function physiologically in vivo. The ability to remediate a diabetic phenotype in a model of type 1 diabetes mellitus is the first step in an effort that may lead to a possible therapy for diabetes.
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Affiliation(s)
- Anne M. Rowzee
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Paola J. Perez-Riveros
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Changyu Zheng
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sarah Krygowski
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Bruce J. Baum
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Niamh X. Cawley
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Lin WJ, Salton SR. The regulated secretory pathway and human disease: insights from gene variants and single nucleotide polymorphisms. Front Endocrinol (Lausanne) 2013; 4:96. [PMID: 23964269 PMCID: PMC3734370 DOI: 10.3389/fendo.2013.00096] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 07/23/2013] [Indexed: 12/15/2022] Open
Abstract
The regulated secretory pathway provides critical control of peptide, growth factor, and hormone release from neuroendocrine and endocrine cells, and neurons, maintaining physiological homeostasis. Propeptides and prohormones are packaged into dense core granules (DCGs), where they frequently undergo tissue-specific processing as the DCG matures. Proteins of the granin family are DCG components, and although their function is not fully understood, data suggest they are involved in DCG formation and regulated protein/peptide secretion, in addition to their role as precursors of bioactive peptides. Association of gene variation, including single nucleotide polymorphisms (SNPs), with neuropsychiatric, endocrine, and metabolic diseases, has implicated specific secreted proteins and peptides in disease pathogenesis. For example, a SNP at position 196 (G/A) of the human brain-derived neurotrophic factor gene dysregulates protein processing and secretion and leads to cognitive impairment. This suggests more generally that variants identified in genes encoding secreted growth factors, peptides, hormones, and proteins involved in DCG biogenesis, protein processing, and the secretory apparatus, could provide insight into the process of regulated secretion as well as disorders that result when it is impaired.
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Affiliation(s)
- Wei-Jye Lin
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Stephen R. Salton
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Geriatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- *Correspondence: Stephen R. Salton, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1065, New York, NY 10029, USA e-mail:
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Woronowicz A, Cawley NX, Peng Loh Y. Carbamazepine Prevents Hippocampal Neurodegeneration in Mice Lacking the Neuroprotective Protein, Carboxypetidase E. ACTA ACUST UNITED AC 2013; Suppl 1:2. [PMID: 25346878 PMCID: PMC4208313 DOI: 10.4172/2167-065x.s1-002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Carboxypeptidase E (CPE) has recently been described as a neuroprotective protein, and in mice devoid of CPE, a complete loss of the hippocampal CA3 neurons is observed. The pattern of loss is characteristic of that caused by status epilepticus. We therefore set out to determine when this loss occurred, what might induce it and if it could be prevented. We found that the hippocampus was intact in 4 week old CPE knock out (KO) mice that had not undergone weaning. However, weaning of 2 or 3 week old CPE KO mice, which involves maternal separation (emotional stress) and ear tagging and tail snipping for genotyping (physical stress), resulted in degeneration of the CA3 neurons by 3 and 4 weeks of age, respectively, while the wild-type mice were unaffected. Moreover, the physical stress caused a more severe neurodegeneration phenotype than the emotional stress of the maternal separation alone. Daily treatment with carbamazepine, an antiepileptic agent, in 2 week old CPE KO mice for 2 weeks prevented the neurodegeneration, despite the weaning process at 3 weeks. No further neurodegeneration was observed 3 weeks post weaning in carbamazepine treated mice. These results showed that degeneration of the CA3 neurons in the hippocampus, previously observed in 6 week old CPE KO mice, is not due to a developmental defect, but caused by physical and emotional stress during the weaning process. This degeneration was prevented by carbamazepine suggesting that the stress associated with weaning caused epileptic-like events in the CPE KO mice.
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Affiliation(s)
- Alicja Woronowicz
- Section on Cellular Neurobiology, Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute on Child Health and Human Development, National Institutes of Health, USA
| | - Niamh X Cawley
- Section on Cellular Neurobiology, Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute on Child Health and Human Development, National Institutes of Health, USA
| | - Y Peng Loh
- Section on Cellular Neurobiology, Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute on Child Health and Human Development, National Institutes of Health, USA
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Sapio MR, Salzmann A, Vessaz M, Crespel A, Lyons PJ, Malafosse A, Fricker LD. Naturally occurring carboxypeptidase A6 mutations: effect on enzyme function and association with epilepsy. J Biol Chem 2012; 287:42900-9. [PMID: 23105115 DOI: 10.1074/jbc.m112.414094] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Carboxypeptidase A6 (CPA6) is a member of the A/B subfamily of M14 metallocarboxypeptidases that is expressed in brain and many other tissues during development. Recently, two mutations in human CPA6 were associated with febrile seizures and/or temporal lobe epilepsy. In this study we screened for additional CPA6 mutations in patients with febrile seizures and focal epilepsy, which encompasses the temporal lobe epilepsy subtype. Mutations found from this analysis as well as CPA6 mutations reported in databases of single nucleotide polymorphisms were further screened by analysis of the modeled proCPA6 protein structure and the functional role of the mutated amino acid. The point mutations predicted to affect activity and/or protein folding were tested by expression of the mutant in HEK293 cells and analysis of the resulting CPA6 protein. Common polymorphisms in CPA6 were also included in this analysis. Several mutations resulted in reduced enzyme activity or CPA6 protein levels in the extracellular matrix. The mutants with reduced extracellular CPA6 protein levels showed normal levels of 50-kDa proCPA6 in the cell, and this could be converted into 37-kDa CPA6 by trypsin, suggesting that protein folding was not greatly affected by the mutations. Interestingly, three of the mutations that reduced extracellular CPA6 protein levels were found in patients with epilepsy. Taken together, these results provide further evidence for the involvement of CPA6 mutations in human epilepsy and reveal additional rare mutations that inactivate CPA6 and could, therefore, also be associated with epileptic phenotypes.
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Affiliation(s)
- Matthew R Sapio
- Department of Neuroscience, Albert Einstein College of Medicine,Bronx, New York 10461,USA
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Analyzing effects of naturally occurring missense mutations. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2012; 2012:805827. [PMID: 22577471 PMCID: PMC3346971 DOI: 10.1155/2012/805827] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/01/2012] [Accepted: 02/01/2012] [Indexed: 11/17/2022]
Abstract
Single-point mutation in genome, for example, single-nucleotide polymorphism (SNP) or rare genetic mutation, is the change of a single nucleotide for another in the genome sequence. Some of them will produce an amino acid substitution in the corresponding protein sequence (missense mutations); others will not. This paper focuses on genetic mutations resulting in a change in the amino acid sequence of the corresponding protein and how to assess their effects on protein wild-type characteristics. The existing methods and approaches for predicting the effects of mutation on protein stability, structure, and dynamics are outlined and discussed with respect to their underlying principles. Available resources, either as stand-alone applications or webservers, are pointed out as well. It is emphasized that understanding the molecular mechanisms behind these effects due to these missense mutations is of critical importance for detecting disease-causing mutations. The paper provides several examples of the application of 3D structure-based methods to model the effects of protein stability and protein-protein interactions caused by missense mutations as well.
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Cawley NX, Wetsel WC, Murthy SRK, Park JJ, Pacak K, Loh YP. New roles of carboxypeptidase E in endocrine and neural function and cancer. Endocr Rev 2012; 33:216-53. [PMID: 22402194 PMCID: PMC3365851 DOI: 10.1210/er.2011-1039] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 01/18/2012] [Indexed: 01/14/2023]
Abstract
Carboxypeptidase E (CPE) or carboxypeptidase H was first discovered in 1982 as an enkephalin-convertase that cleaved a C-terminal basic residue from enkephalin precursors to generate enkephalin. Since then, CPE has been shown to be a multifunctional protein that subserves many essential nonenzymatic roles in the endocrine and nervous systems. Here, we review the phylogeny, structure, and function of CPE in hormone and neuropeptide sorting and vesicle transport for secretion, alternative splicing of the CPE transcript, and single nucleotide polymorphisms in humans. With this and the analysis of mutant and knockout mice, the data collectively support important roles for CPE in the modulation of metabolic and glucose homeostasis, bone remodeling, obesity, fertility, neuroprotection, stress, sexual behavior, mood and emotional responses, learning, and memory. Recently, a splice variant form of CPE has been found to be an inducer of tumor growth and metastasis and a prognostic biomarker for metastasis in endocrine and nonendocrine tumors.
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Affiliation(s)
- Niamh X Cawley
- Section on Cellular Neurobiology, Program on Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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Doss CGP, NagaSundaram N. Investigating the structural impacts of I64T and P311S mutations in APE1-DNA complex: a molecular dynamics approach. PLoS One 2012; 7:e31677. [PMID: 22384055 PMCID: PMC3288039 DOI: 10.1371/journal.pone.0031677] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Accepted: 01/11/2012] [Indexed: 11/25/2022] Open
Abstract
Background Elucidating the molecular dynamic behavior of Protein-DNA complex upon mutation is crucial in current genomics. Molecular dynamics approach reveals the changes on incorporation of variants that dictate the structure and function of Protein-DNA complexes. Deleterious mutations in APE1 protein modify the physicochemical property of amino acids that affect the protein stability and dynamic behavior. Further, these mutations disrupt the binding sites and prohibit the protein to form complexes with its interacting DNA. Principal Findings In this study, we developed a rapid and cost-effective method to analyze variants in APE1 gene that are associated with disease susceptibility and evaluated their impacts on APE1-DNA complex dynamic behavior. Initially, two different in silico approaches were used to identify deleterious variants in APE1 gene. Deleterious scores that overlap in these approaches were taken in concern and based on it, two nsSNPs with IDs rs61730854 (I64T) and rs1803120 (P311S) were taken further for structural analysis. Significance Different parameters such as RMSD, RMSF, salt bridge, H-bonds and SASA applied in Molecular dynamic study reveals that predicted deleterious variants I64T and P311S alters the structure as well as affect the stability of APE1-DNA interacting functions. This study addresses such new methods for validating functional polymorphisms of human APE1 which is critically involved in causing deficit in repair capacity, which in turn leads to genetic instability and carcinogenesis.
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Affiliation(s)
- C. George Priya Doss
- Centre for Nanobiotechnology, Medical Biotechnology Division, School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu, India
- * E-mail:
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Zhang Z, Wang L, Gao Y, Zhang J, Zhenirovskyy M, Alexov E. Predicting folding free energy changes upon single point mutations. ACTA ACUST UNITED AC 2012; 28:664-71. [PMID: 22238268 DOI: 10.1093/bioinformatics/bts005] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
MOTIVATION The folding free energy is an important characteristic of proteins stability and is directly related to protein's wild-type function. The changes of protein's stability due to naturally occurring mutations, missense mutations, are typically causing diseases. Single point mutations made in vitro are frequently used to assess the contribution of given amino acid to the stability of the protein. In both cases, it is desirable to predict the change of the folding free energy upon single point mutations in order to either provide insights of the molecular mechanism of the change or to design new experimental studies. RESULTS We report an approach that predicts the free energy change upon single point mutation by utilizing the 3D structure of the wild-type protein. It is based on variation of the molecular mechanics Generalized Born (MMGB) method, scaled with optimized parameters (sMMGB) and utilizing specific model of unfolded state. The corresponding mutations are built in silico and the predictions are tested against large dataset of 1109 mutations with experimentally measured changes of the folding free energy. Benchmarking resulted in root mean square deviation = 1.78 kcal/mol and slope of the linear regression fit between the experimental data and the calculations was 1.04. The sMMGB is compared with other leading methods of predicting folding free energy changes upon single mutations and results discussed with respect to various parameters. AVAILABILITY All the pdb files we used in this article can be downloaded from http://compbio.clemson.edu/downloadDir/mentaldisorders/sMMGB_pdb.rar. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Zhe Zhang
- Computational Biophysics and Bioinformatics, Department of Physics, Clemson University, Clemson, SC 29634, USA
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Lai HM, Chen CJ, Su BYJ, Chen YC, Yu SF, Yen JH, Hsieh MC, Cheng TT, Chang SJ. Gout and type 2 diabetes have a mutual inter-dependent effect on genetic risk factors and higher incidences. Rheumatology (Oxford) 2011; 51:715-20. [PMID: 22179738 DOI: 10.1093/rheumatology/ker373] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE To explore the causal relationship between gout and Type 2 diabetes based on genetic evidence and national outpatient database. METHODS Twenty male gout patients with early-onset, gout family history, without a habit of alcohol consumption or obesity before the first attack of gout were selected from hospital in 2010; and 42 unrelated male Chinese subjects were selected from HapMap as controls for genome-wide analysis study (GWAS). The comorbid diseases with gout were revealed by applying the significant single nucleotide polymorphisms (SNPs) to MetaCore platform, and the comorbid relationship was analysed by standardized incidence ratio (SIR) from outpatient database. RESULTS A total of 334 SNPs were significantly related to gout in GWAS (P < 10(-7)), and Type 2 diabetes was the most significantly associated disease with gout as recognized by 36 gene symbols correspondent to the above significant SNPs. The analysis of national outpatient database showed that the overall incident Type 2 diabetes was 1.50 cases per 1000 person-months among gout patients, which was higher than the overall incident gout (1.06 cases) among Type 2 diabetes. The age-adjusted SIR of incident Type 2 diabetes among gout was 2.59 (95% CI 2.42, 2.78), whereas the age-adjusted SIR for incident gout among Type 2 diabetes was 1.61 (95% CI 1.48, 1.74). CONCLUSION After excluding obesity and alcohol consumption behaviour, this study showed that patients with gout and Type 2 diabetes shared the common genetic factors most, and that there existed a mutual inter-dependent effect on higher incidences.
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Affiliation(s)
- Han-Ming Lai
- Division of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
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Zhang Z, Norris J, Schwartz C, Alexov E. In silico and in vitro investigations of the mutability of disease-causing missense mutation sites in spermine synthase. PLoS One 2011; 6:e20373. [PMID: 21647366 PMCID: PMC3103547 DOI: 10.1371/journal.pone.0020373] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 04/30/2011] [Indexed: 01/17/2023] Open
Abstract
Background Spermine synthase (SMS) is a key enzyme controlling the concentration of spermidine and spermine in the cell. The importance of SMS is manifested by the fact that single missense mutations were found to cause Snyder-Robinson Syndrome (SRS). At the same time, currently there are no non-synonymous single nucleoside polymorphisms, nsSNPs (harmless mutations), found in SMS, which may imply that the SMS does not tolerate amino acid substitutions, i.e. is not mutable. Methodology/Principal Findings To investigate the mutability of the SMS, we carried out in silico analysis and in vitro experiments of the effects of amino acid substitutions at the missense mutation sites (G56, V132 and I150) that have been shown to cause SRS. Our investigation showed that the mutation sites have different degree of mutability depending on their structural micro-environment and involvement in the function and structural integrity of the SMS. It was found that the I150 site does not tolerate any mutation, while V132, despite its key position at the interface of SMS dimer, is quite mutable. The G56 site is in the middle of the spectra, but still quite sensitive to charge residue replacement. Conclusions/Significance The performed analysis showed that mutability depends on the detail of the structural and functional factors and cannot be predicted based on conservation of wild type properties alone. Also, harmless nsSNPs can be expected to occur even at sites at which missense mutations were found to cause diseases.
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Affiliation(s)
- Zhe Zhang
- Computational Biophysics and Bioinformatics, Department of Physics, Clemson University, Clemson, South Carolina, United States of America
| | - Joy Norris
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina, United States of America
| | - Charles Schwartz
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina, United States of America
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
| | - Emil Alexov
- Computational Biophysics and Bioinformatics, Department of Physics, Clemson University, Clemson, South Carolina, United States of America
- * E-mail:
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Carboxypeptidase E: elevated expression correlated with tumor growth and metastasis in pheochromocytomas and other cancers. Cell Mol Neurobiol 2011; 30:1377-81. [PMID: 21061162 DOI: 10.1007/s10571-010-9592-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 09/02/2010] [Indexed: 12/20/2022]
Abstract
Expression of carboxypeptidase E (CPE), a prohormone processing enzyme in different cancer types, was analyzed from data in the GEO profile database (http://www.ncbi.nlm.nih.gov/geo/) and experimentally in pheochromocytomas. Analysis of microarray data demonstrated that significantly elevated levels of CPE mRNA was found in many metastatic non-endocrine cancers: cervical, colon rectal, renal cancers, Ewing sarcomas (bone cancer), and various types of astrocytomas and oligodendrogliomas, whereas expression of CPE mRNA was virtually absent in their respective counterpart normal tissues. Moreover, there was higher CPE mRNA expression in cells from the metastatic tumor compared to those from the primary tumor in colorectal cancer. Elevated CPE mRNA expression was found in neuroendocrine tumors in lung and pituitary adenomas, although the significance is unclear since endocrine and neuroendocrine cells normally express CPE. However, studies of neuroendocrine tumors, pheochromocytomas, revealed expression of not only wild-type CPE, but a variant which was correlated with tumor behavior. Extremely high CPE mRNA copy numbers of the variant were found in very large or invasive tumors, both of which usually indicate poor prognosis. Thus, collectively the data suggest that CPE may play a role in promoting tumor growth and invasion. CPE could potentially serve as a diagnostic and prognostic biomarker for metastasis in different cancer types.
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Wardlaw SL. Hypothalamic proopiomelanocortin processing and the regulation of energy balance. Eur J Pharmacol 2011; 660:213-9. [PMID: 21208604 DOI: 10.1016/j.ejphar.2010.10.107] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 09/27/2010] [Accepted: 10/12/2010] [Indexed: 12/18/2022]
Abstract
Hypothalamic proopiomelanocortin (POMC) neurons play a key role in regulating energy balance and neuroendocrine function. Much attention has been focused on the regulation of POMC gene expression with less emphasis on regulated peptide processing. This is particularly important given the complexity of posttranslational POMC processing which is essential for the generation of biologically active MSH peptides. Mutations that impair POMC sorting and processing are associated with obesity in humans and in animals. Specifically, mutations in the POMC processing enzymes prohormone convertase 1/3 (PC1/3) and in carboxypeptidase E (CPE) and in the α-MSH degrading enzyme, PRCP, are associated with changes in energy balance. There is increasing evidence that POMC processing is regulated with respect to energy balance. Studies have implicated both the leptin and insulin signaling pathways in the regulation of POMC at various steps in the processing pathway. This article will review the role of hypothalamic POMC in regulating energy balance with a focus on POMC processing.
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Affiliation(s)
- Sharon L Wardlaw
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, United States.
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Cawley NX, Yanik T, Woronowicz A, Chang W, Marini JC, Loh YP. Obese carboxypeptidase E knockout mice exhibit multiple defects in peptide hormone processing contributing to low bone mineral density. Am J Physiol Endocrinol Metab 2010; 299:E189-97. [PMID: 20460579 PMCID: PMC2928512 DOI: 10.1152/ajpendo.00516.2009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carboxypeptidase E (CPE) is a prohormone/proneuropeptide processing enzyme, and mice bearing CPE mutations exhibit an obese and diabetic phenotype. Studies on CPE knockout (KO) mice revealed poor prohormone processing, resulting in deficiencies in peptide hormones/neuropeptides such as insulin, gonadotropin-releasing hormone, and cocaine- and amphetamine-regulated transcript (CART). Here, we show that CPE KO mice, an obese animal model, have low bone mineral density (BMD) accompanied by elevated plasma CTX-1 (carboxy-terminal collagen crosslinks), and osteocalcin, indicators of increased bone turnover. Receptor activator for NF-kappaB ligand (RANKL) expression was elevated approximately 2-fold relative to osteoprotegerin in the femur of KO animals, suggesting increased osteoclastic activity in the KO mice. In the hypothalamus, mature CART, a peptide involved in eating behavior and implicated in bone metabolism, was undetectable. The melanocortin and neuropeptide Y (NPY) systems in the hypothalamus have also been implicated in bone remodeling, since MC4R KO and NPY KO mice have increased BMD. However, reduction of alpha-MSH, the primary ligand of MC4R by up to 94% and the lack of detectable NPY in the hypothalamus of CPE KO do not recapitulate the single-gene KO phenotypes. This study highlights the complex physiological interplay between peptides involved in energy metabolism and bone formation and furthermore suggests the possibility that patients, bearing CPE and CART mutations leading to inactive forms of these molecules, may be at a higher risk of developing osteoporosis.
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Affiliation(s)
- Niamh X Cawley
- Section on Cellular Neurobiology, Program on Developmental Neuroscience,Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 49 Convent Dr., Bethesda, MD 20892, USA
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Reardon W, Mullen AM, Sweeney T, Hamill RM. Association of polymorphisms in candidate genes with colour, water-holding capacity, and composition traits in bovine M. longissimus and M. semimembranosus. Meat Sci 2010; 86:270-5. [PMID: 20510534 DOI: 10.1016/j.meatsci.2010.04.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 03/11/2010] [Accepted: 04/11/2010] [Indexed: 01/08/2023]
Abstract
The objective of this study was to determine the association of single nucleotide polymorphisms (SNP) in selected candidate genes with sensory and technological meat quality traits in commercial cattle. SNP in seven candidate genes were genotyped in 130 crossbred Bos taurus cattle using PCR-RFLP. Reported associations between calpastatin (CAST) and Warner-Bratzler shear force and carboxypeptidase E (CPE) and intra-muscular fat were not confirmed. However, SNP in CAST, amp-activated protein kinase, gamma-3 subunit (PRKAG3), growth hormone receptor (GHR) and stearoyl coA desaturase (SCD) genes were significantly associated with colour traits (p<0.05). The PRKAG3 SNP was additionally associated with cook loss in M. longissimus thoracis et lumborum (p<0.05) and tended towards association in M. semimembranosus (p<0.1). An association with pH was identified for the SCD SNP (p<0.001). The GHR polymorphism was influential on moisture and intra-muscular fat in M. semimembranosus and protein content in both muscles (p<0.05). Only CPE was associated with sensory traits (flavour in M. longissimus, p<0.01).
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Affiliation(s)
- W Reardon
- Teagasc, Ashtown Food Research Centre, Ashtown, Dublin 15, Ireland
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Pilot-Storck F, Chopin E, Rual JF, Baudot A, Dobrokhotov P, Robinson-Rechavi M, Brun C, Cusick ME, Hill DE, Schaeffer L, Vidal M, Goillot E. Interactome mapping of the phosphatidylinositol 3-kinase-mammalian target of rapamycin pathway identifies deformed epidermal autoregulatory factor-1 as a new glycogen synthase kinase-3 interactor. Mol Cell Proteomics 2010; 9:1578-93. [PMID: 20368287 DOI: 10.1074/mcp.m900568-mcp200] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The phosphatidylinositol 3-kinase-mammalian target of rapamycin (PI3K-mTOR) pathway plays pivotal roles in cell survival, growth, and proliferation downstream of growth factors. Its perturbations are associated with cancer progression, type 2 diabetes, and neurological disorders. To better understand the mechanisms of action and regulation of this pathway, we initiated a large scale yeast two-hybrid screen for 33 components of the PI3K-mTOR pathway. Identification of 67 new interactions was followed by validation by co-affinity purification and exhaustive literature curation of existing information. We provide a nearly complete, functionally annotated interactome of 802 interactions for the PI3K-mTOR pathway. Our screen revealed a predominant place for glycogen synthase kinase-3 (GSK3) A and B and the AMP-activated protein kinase. In particular, we identified the deformed epidermal autoregulatory factor-1 (DEAF1) transcription factor as an interactor and in vitro substrate of GSK3A and GSK3B. Moreover, GSK3 inhibitors increased DEAF1 transcriptional activity on the 5-HT1A serotonin receptor promoter. We propose that DEAF1 may represent a therapeutic target of lithium and other GSK3 inhibitors used in bipolar disease and depression.
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Affiliation(s)
- Fanny Pilot-Storck
- UMR5239 Laboratoire de Biologie Moléculaire de la Cellule, Ecole Normale Supérieure de Lyon, Lyon, France
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Zhang X, Pan H, Peng B, Steiner DF, Pintar JE, Fricker LD. Neuropeptidomic analysis establishes a major role for prohormone convertase-2 in neuropeptide biosynthesis. J Neurochem 2009; 112:1168-79. [PMID: 19968759 DOI: 10.1111/j.1471-4159.2009.06530.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Prohormone convertase 2 (PC2) functions in the generation of neuropeptides from their precursors. A quantitative peptidomics approach was used to evaluate the role of PC2 in the processing of peptides in a variety of brain regions. Altogether, 115 neuropeptides or other peptides derived from secretory pathway proteins were identified. These peptides arise from 28 distinct secretory pathway proteins, including proenkephalin, proopiomelanocortin, prodynorphin, protachykinin A and B, procholecystokinin, and many others. Forty one of the peptides found in wild-type (WT) mice were not detectable in any of the brain regions of PC2 knockout mice, and another 24 peptides were present at levels ranging from 20% to 79% of WT levels. Most of the other peptides were not substantially affected by the mutation, with levels ranging from 80% to 120% of WT levels, and only three peptides were found to increase in one or more brain regions of PC2 knockout mice. Taken together, these results are consistent with a broad role for PC2 in neuropeptide processing, but with functional redundancy for many of the cleavages. Comparison of the cleavage sites affected by the absence of PC2 confirms previous suggestions that sequences with a Trp, Tyr, and/or Pro in the P1' or P2' position are preferentially cleaved by PC2 and not by other enzymes present in the secretory pathway.
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Affiliation(s)
- Xin Zhang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Plum L, Lin HV, Dutia R, Tanaka J, Aizawa KS, Matsumoto M, Kim AJ, Cawley NX, Paik JH, Loh YP, DePinho RA, Wardlaw SL, Accili D. The obesity susceptibility gene Cpe links FoxO1 signaling in hypothalamic pro-opiomelanocortin neurons with regulation of food intake. Nat Med 2009; 15:1195-201. [PMID: 19767734 PMCID: PMC2777744 DOI: 10.1038/nm.2026] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Accepted: 08/11/2009] [Indexed: 12/03/2022]
Abstract
Reduced food intake brings about an adaptive decrease in energy expenditure that contributes to the recidivism of obesity following weight loss. Insulin and leptin inhibit food intake through actions in the central nervous system that are partly mediated by FoxO1. We show that FoxO1 ablation in pro–opiomelanocortin (Pomc) neurons (Pomc–Foxo1−/−) reduces food intake without affecting energy expenditure. Analyses of hypothalamic neuropeptides in Pomc–Foxo1−/− mice reveal selective increases of α–Msh and COOH–cleaved β–endorphin, the products of Carboxypeptidase E (Cpe)–dependent processing of Pomc. We show that Cpe is decreased in diet–induced obesity, and that FoxO1 deletion offsets the decrease, protecting against weight gain. Moreover, moderate Cpe overexpression in the arcuate nucleus phenocopies features of the FoxO1 mutation. The dissociation of food intake from energy expenditure in Pomc–Foxo1−/− mice represents a model for therapeutic intervention in obesity, and raises the possibility of targeting Cpe to develop weight loss medications.
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Affiliation(s)
- Leona Plum
- Naomi Berrie Diabetes Center and Department of Medicine, Columbia University, New York, New York, USA
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Carboxypeptidase M: Multiple alliances and unknown partners. Clin Chim Acta 2009; 399:24-39. [DOI: 10.1016/j.cca.2008.10.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 10/02/2008] [Accepted: 10/02/2008] [Indexed: 01/25/2023]
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Zhang X, Che FY, Berezniuk I, Sonmez K, Toll L, Fricker LD. Peptidomics of Cpe(fat/fat) mouse brain regions: implications for neuropeptide processing. J Neurochem 2008; 107:1596-613. [PMID: 19014391 DOI: 10.1111/j.1471-4159.2008.05722.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Quantitative peptidomics was used to compare levels of peptides in wild type (WT) and Cpe(fat/fat) mice, which lack carboxypeptidase E (CPE) activity because of a point mutation. Six different brain regions were analyzed: amygdala, hippocampus, hypothalamus, prefrontal cortex, striatum, and thalamus. Altogether, 111 neuropeptides or other peptides derived from secretory pathway proteins were identified in WT mouse brain extracts by tandem mass spectrometry, and another 47 peptides were tentatively identified based on mass and other criteria. Most secretory pathway peptides were much lower in Cpe(fat/fat) mouse brain, relative to WT mouse brain, indicating that CPE plays a major role in their biosynthesis. Other peptides were only partially reduced in the Cpe(fat/fat) mice, indicating that another enzyme (presumably carboxypeptidase D) contributes to their biosynthesis. Approximately 10% of the secretory pathway peptides were present in the Cpe(fat/fat) mouse brain at levels similar to those in WT mouse brain. Many peptides were greatly elevated in the Cpe(fat/fat) mice; these peptide processing intermediates with C-terminal Lys and/or Arg were generally not detectable in WT mice. Taken together, these results indicate that CPE contributes, either directly or indirectly, to the production of the majority of neuropeptides.
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Affiliation(s)
- Xin Zhang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Carboxypeptidase E mediates palmitate-induced beta-cell ER stress and apoptosis. Proc Natl Acad Sci U S A 2008; 105:8452-7. [PMID: 18550819 DOI: 10.1073/pnas.0711232105] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Obesity is a principal risk factor for type 2 diabetes, and elevated fatty acids reduce beta-cell function and survival. An unbiased proteomic screen was used to identify targets of palmitate in beta-cell death. The most significantly altered protein in both human islets and MIN6 beta-cells treated with palmitate was carboxypeptidase E (CPE). Palmitate reduced CPE protein levels within 2 h, preceding endoplasmic reticulum (ER) stress and cell death, by a mechanism involving CPE translocation to Golgi and lysosomal degradation. Palmitate metabolism and Ca(2+) flux were also required for CPE proteolysis and beta-cell death. Chronic palmitate exposure increased the ratio of proinsulin to insulin. CPE null islets had increased apoptosis in vivo and in vitro. Reducing CPE by approximately 30% using shRNA also increased ER stress and apoptosis. Conversely, overexpression of CPE partially rescued beta-cells from palmitate-induced ER stress and apoptosis. Thus, carboxypeptidase E degradation contributes to palmitate-induced beta-cell ER stress and apoptosis. CPE is a major link between hyperlipidemia and beta-cell death pathways in diabetes.
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Wang J, Zhang Y, Yang ZJ, Zhu TB, Wang LS, Chen B, Cao KJ, Huang J, Ma WZ, Jia EZ. Association of human carboxypeptidase E exon5 gene polymorphisms with angiographical characteristics of coronary atherosclerosis in a Chinese population. Acta Pharmacol Sin 2008; 29:736-44. [PMID: 18501121 DOI: 10.1111/j.1745-7254.2008.00798.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
AIM To explore the association between 801C>T and 847C>T polymorphisms of the human carboxypeptidase E (CPE) gene exon5, which could cause hyperproinsulinemia, and the angiographical characteristics of coronary atherosclerosis. METHODS In total, 1044 consecutive patients who underwent coronary angiography for suspected or known coronary atherosclerosis were examined with respect to their genotypes, insulin, proinsulin level, and other risk factors of coronary atherosclerosis. The angiographical characteristics of coronary atherosclerosis (ie the severity of coronary heart disease) were defined by Gensinios score (GS) system. RESULTS The results showed that the genotype frequencies of CC, CT, and TT at 801C>T locus were significantly different among the patients of the 4 groups who were classified by quartile values of GS (P=0.033). However, the frequency of the 847T allele was 0 for all the patients. The ordinal logistic regression analysis revealed that the increased risk of angiographical characteristics of coronary atherosclerosis were associated with CPE 801CT/TT variant genotypes [adjusted odds ratio (OR)=1.23, 95% confidence interval (CI) =0.93-1.63 for 801CT and adjusted OR=3.13, 95% CI=1.18-8.28 for 801TT] compared with the 801CC wild-type homozygotes. A stratification analysis showed that the effects of the CPE 801TT genotype were more evident among subgroups with relatively older (> or = 60 years) patients, males, and smokers. Furthermore, an analysis of covariance controlling age, sex, and body mass index indicated that differences of blood glucose, insulin, insulin resistance, and the proinsulin level between 801C>T genotype groups were not statistically significant. CONCLUSION These findings indicate that the 801C>T polymorphism in the CPE exon5 gene may contribute to the angiographical characteristics of coronary atherosclerosis in the Chinese population.
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Affiliation(s)
- Jie Wang
- Department of Epidemiology and Biostatistics, Nanjing Medical University, Nanjing 210029, China
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