1
|
Dill H, Liewald JF, Becker M, Seidenthal M, Gottschalk A. Neuropeptidergic regulation of neuromuscular signaling in larval zebrafish alters swimming behavior and synaptic transmission. iScience 2024; 27:110687. [PMID: 39252958 PMCID: PMC11381845 DOI: 10.1016/j.isci.2024.110687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/13/2024] [Accepted: 08/05/2024] [Indexed: 09/11/2024] Open
Abstract
Chemical synaptic transmission is modulated to accommodate different activity levels, thus enabling homeostatic scaling in pre- and postsynaptic compartments. In nematodes, cholinergic neurons use neuropeptide signaling to modulate synaptic vesicle content. To explore if this mechanism is conserved in vertebrates, we studied the involvement of neuropeptides in cholinergic transmission at the neuromuscular junction of larval zebrafish. Optogenetic stimulation by photoactivated adenylyl cyclase evoked locomotion. We generated mutants lacking the neuropeptide-processing enzyme carboxypeptidase E (cpe), and the most abundant neuropeptide precursor in motor neurons, tachykinin (tac1). Both mutants showed exaggerated locomotion after photostimulation. Recording excitatory postsynaptic currents demonstrated overall larger amplitudes in the wild type. Exaggerated locomotion in the mutants thus reflected upscaling of postsynaptic excitability. Both mutant muscles expressed more nicotinic acetylcholine receptors (nAChRs) on their surface; thus, neuropeptide signaling regulates synaptic transmitter output in zebrafish motor neurons, and muscle cells homeostatically regulate nAChR surface expression, compensating reduced presynaptic input.
Collapse
Affiliation(s)
- Holger Dill
- Buchmann Institute, Goethe University, Max-von-Laue-Strasse 15, D-60438 Frankfurt, Germany
- Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, D-60438 Frankfurt, Germany
| | - Jana F Liewald
- Buchmann Institute, Goethe University, Max-von-Laue-Strasse 15, D-60438 Frankfurt, Germany
- Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, D-60438 Frankfurt, Germany
| | - Michelle Becker
- Buchmann Institute, Goethe University, Max-von-Laue-Strasse 15, D-60438 Frankfurt, Germany
- Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, D-60438 Frankfurt, Germany
| | - Marius Seidenthal
- Buchmann Institute, Goethe University, Max-von-Laue-Strasse 15, D-60438 Frankfurt, Germany
- Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, D-60438 Frankfurt, Germany
| | - Alexander Gottschalk
- Buchmann Institute, Goethe University, Max-von-Laue-Strasse 15, D-60438 Frankfurt, Germany
- Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, D-60438 Frankfurt, Germany
| |
Collapse
|
2
|
Jiang D, Liu H, Li T, Zhao S, Yang K, Yao F, Zhou B, Feng H, Wang S, Shen J, Tang J, Zhang YX, Wang Y, Guo C, Tang TS. Agomirs upregulating carboxypeptidase E expression rescue hippocampal neurogenesis and memory deficits in Alzheimer's disease. Transl Neurodegener 2024; 13:24. [PMID: 38671492 PMCID: PMC11046780 DOI: 10.1186/s40035-024-00414-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Adult neurogenesis occurs in the subventricular zone (SVZ) and the subgranular zone of the dentate gyrus in the hippocampus. The neuronal stem cells in these two neurogenic niches respond differently to various physiological and pathological stimuli. Recently, we have found that the decrement of carboxypeptidase E (CPE) with aging impairs the maturation of brain-derived neurotrophic factor (BDNF) and neurogenesis in the SVZ. However, it remains unknown whether these events occur in the hippocampus, and what the role of CPE is in the adult hippocampal neurogenesis in the context of Alzheimer's disease (AD). METHODS In vivo screening was performed to search for miRNA mimics capable of upregulating CPE expression and promoting neurogenesis in both neurogenic niches. Among these, two agomirs were further assessed for their effects on hippocampal neurogenesis in the context of AD. We also explored whether these two agomirs could ameliorate behavioral symptoms and AD pathology in mice, using direct intracerebroventricular injection or by non-invasive intranasal instillation. RESULTS Restoration of CPE expression in the hippocampus improved BDNF maturation and boosted adult hippocampal neurogenesis. By screening the miRNA mimics targeting the 5'UTR region of Cpe gene, we developed two agomirs that were capable of upregulating CPE expression. The two agomirs significantly rescued adult neurogenesis and cognition, showing multiple beneficial effects against the AD-associated pathologies in APP/PS1 mice. Of note, noninvasive approach via intranasal delivery of these agomirs improved the behavioral and neurocognitive functions of APP/PS1 mice. CONCLUSIONS CPE may regulate adult hippocampal neurogenesis via the CPE-BDNF-TrkB signaling pathway. This study supports the prospect of developing miRNA agomirs targeting CPE as biopharmaceuticals to counteract aging- and disease-related neurological decline in human brains.
Collapse
Affiliation(s)
- Dongfang Jiang
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hongmei Liu
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China.
| | - Tingting Li
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Song Zhao
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Keyan Yang
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Fuwen Yao
- Beijing Institute of Genomics, Chinese Academy of Sciences/China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Bo Zhou
- Beijing Institute of Genomics, Chinese Academy of Sciences/China National Center for Bioinformation, Beijing, 100101, China
| | - Haiping Feng
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Sijia Wang
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jiaqi Shen
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jinglan Tang
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- Present Address: Department of Psychology, UC San Diego, La Jolla, CA, 92093, USA
| | - Yu-Xin Zhang
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yun Wang
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Caixia Guo
- Beijing Institute of Genomics, Chinese Academy of Sciences/China National Center for Bioinformation, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Tie-Shan Tang
- Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
| |
Collapse
|
3
|
Štepihar D, Florke Gee RR, Hoyos Sanchez MC, Fon Tacer K. Cell-specific secretory granule sorting mechanisms: the role of MAGEL2 and retromer in hypothalamic regulated secretion. Front Cell Dev Biol 2023; 11:1243038. [PMID: 37799273 PMCID: PMC10548473 DOI: 10.3389/fcell.2023.1243038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/31/2023] [Indexed: 10/07/2023] Open
Abstract
Intracellular protein trafficking and sorting are extremely arduous in endocrine and neuroendocrine cells, which synthesize and secrete on-demand substantial quantities of proteins. To ensure that neuroendocrine secretion operates correctly, each step in the secretion pathways is tightly regulated and coordinated both spatially and temporally. At the trans-Golgi network (TGN), intrinsic structural features of proteins and several sorting mechanisms and distinct signals direct newly synthesized proteins into proper membrane vesicles that enter either constitutive or regulated secretion pathways. Furthermore, this anterograde transport is counterbalanced by retrograde transport, which not only maintains membrane homeostasis but also recycles various proteins that function in the sorting of secretory cargo, formation of transport intermediates, or retrieval of resident proteins of secretory organelles. The retromer complex recycles proteins from the endocytic pathway back to the plasma membrane or TGN and was recently identified as a critical player in regulated secretion in the hypothalamus. Furthermore, melanoma antigen protein L2 (MAGEL2) was discovered to act as a tissue-specific regulator of the retromer-dependent endosomal protein recycling pathway and, by doing so, ensures proper secretory granule formation and maturation. MAGEL2 is a mammalian-specific and maternally imprinted gene implicated in Prader-Willi and Schaaf-Yang neurodevelopmental syndromes. In this review, we will briefly discuss the current understanding of the regulated secretion pathway, encompassing anterograde and retrograde traffic. Although our understanding of the retrograde trafficking and sorting in regulated secretion is not yet complete, we will review recent insights into the molecular role of MAGEL2 in hypothalamic neuroendocrine secretion and how its dysregulation contributes to the symptoms of Prader-Willi and Schaaf-Yang patients. Given that the activation of many secreted proteins occurs after they enter secretory granules, modulation of the sorting efficiency in a tissue-specific manner may represent an evolutionary adaptation to environmental cues.
Collapse
Affiliation(s)
- Denis Štepihar
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Rebecca R. Florke Gee
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Maria Camila Hoyos Sanchez
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Klementina Fon Tacer
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| |
Collapse
|
4
|
Hymer WC, Kraemer WJ. Resistance exercise stress: theoretical mechanisms for growth hormone processing and release from the anterior pituitary somatotroph. Eur J Appl Physiol 2023; 123:1867-1878. [PMID: 37421488 DOI: 10.1007/s00421-023-05263-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 06/15/2023] [Indexed: 07/10/2023]
Abstract
Heavy resistance exercise (HRE) is the most effective method for inducing muscular hypertrophy and stimulating anabolic hormones, including growth hormone, into the blood. In this review, we explore possible mechanisms within the GH secretory pathway of the pituitary somatotroph, which are likely to modulate the flow of hormone synthesis and packaging as it is processed prior to exocytosis. Special emphasis is placed on the secretory granule and its possible role as a signaling hub. We also review data that summarize how HRE affects the quality and quantity of the secreted hormone. Finally, these pathway mechanisms are considered in the context of heterogeneity of the somatotroph population in the anterior pituitary.
Collapse
Affiliation(s)
- Wesley C Hymer
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - William J Kraemer
- Department of Human Sciences, The Ohio State University, Columbus, OH, 43802, USA.
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA.
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA.
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia.
| |
Collapse
|
5
|
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.
Collapse
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.
| |
Collapse
|
6
|
Hareendran S, Yang X, Sharma VK, Loh YP. Carboxypeptidase E and its splice variants: Key regulators of growth and metastasis in multiple cancer types. Cancer Lett 2022; 548:215882. [PMID: 35988818 PMCID: PMC9532369 DOI: 10.1016/j.canlet.2022.215882] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 02/07/2023]
Abstract
Mechanisms driving tumor growth and metastasis are complex, and involve the recruitment of many genes working in concert with each other. The tumor is characterized by the expression of specific sets of genes depending on its environment. Here we review the role of the carboxypeptidase E (CPE) gene which has been shown to be important in driving growth, survival and metastasis in many cancer types. CPE was first discovered as a prohormone processing enzyme, enriched in endocrine tumors, and later found to be expressed and secreted from many epithelial-derived tumors and cancer cell lines. Numerous studies have shown that besides wild-type CPE, a N-terminal truncated splice variant form of CPE (CPE-ΔN) has been cloned and found to be highly expressed in malignant tumors and cell lines derived from prostate, breast, liver and lung cancers and gliomas. The mechanisms of action of CPE and the splice variant in promoting tumor growth and metastasis in different cancer types are discussed. Mechanistically, secreted CPE activates the Erk/wnt pathways, while CPE-ΔN interacts with HDACs in a protein complex in the nucleus, to recruit various cell cycle genes and metastatic genes, respectively. Clinical studies suggest that CPE and CPE-ΔN mRNA and protein are potential diagnostic and prognostic biomarkers for multiple cancer types, assayed using solid tumors and secreted serum exosomes. CPE has been shown to be a therapeutic target for multiple cancer types. CPE/CPE-ΔN siRNA transported via exosomes and taken up by recipient high metastatic cancer cells, suppressed growth and proliferation of these cells. Thus future studies, delivering CPE/CPE-ΔN siRNA, perhaps via exosomes, to the tumor could be a novel treatment approach to suppress tumor growth and metastasis.
Collapse
Affiliation(s)
- Sangeetha Hareendran
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Md, 20892, USA
| | - Xuyu Yang
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Md, 20892, USA
| | - Vinay Kumar Sharma
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Md, 20892, USA
| | - 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.
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Exosomal Carboxypeptidase E (CPE) and CPE-shRNA-Loaded Exosomes Regulate Metastatic Phenotype of Tumor Cells. Int J Mol Sci 2022; 23:ijms23063113. [PMID: 35328535 PMCID: PMC8953963 DOI: 10.3390/ijms23063113] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/05/2022] [Accepted: 03/08/2022] [Indexed: 01/27/2023] Open
Abstract
Background: Exosomes promote tumor growth and metastasis through intercellular communication, although the mechanism remains elusive. Carboxypeptidase E (CPE) supports the progression of different cancers, including hepatocellular carcinoma (HCC). Here, we investigated whether CPE is the bioactive cargo within exosomes, and whether it contributes to tumorigenesis, using HCC cell lines as a cancer model. Methods: Exosomes were isolated from supernatant media of cancer cells, or human sera. mRNA and protein expression were analyzed using PCR and Western blot. Low-metastatic HCC97L cells were incubated with exosomes derived from high-metastatic HCC97H cells. In other experiments, HCC97H cells were incubated with CPE-shRNA-loaded exosomes. Cell proliferation and invasion were assessed using MTT, colony formation, and matrigel invasion assays. Results: Exosomes released from cancer cells contain CPE mRNA and protein. CPE mRNA levels are enriched in exosomes secreted from high- versus low-metastastic cells, across various cancer types. In a pilot study, significantly higher CPE copy numbers were found in serum exosomes from cancer patients compared to healthy subjects. HCC97L cells, treated with exosomes derived from HCC97H cells, displayed enhanced proliferation and invasion; however, exosomes from HCC97H cells pre-treated with CPE-shRNA failed to promote proliferation. When HEK293T exosomes loaded with CPE-shRNA were incubated with HCC97H cells, the expression of CPE, Cyclin D1, a cell-cycle regulatory protein and c-myc, a proto-oncogene, were suppressed, resulting in the diminished proliferation of HCC97H cells. Conclusions: We identified CPE as an exosomal bioactive molecule driving the growth and invasion of low-metastatic HCC cells. CPE-shRNA loaded exosomes can inhibit malignant tumor cell proliferation via Cyclin D1 and c-MYC suppression. Thus, CPE is a key player in the exosome transmission of tumorigenesis, and the exosome-based delivery of CPE-shRNA offers a potential treatment for tumor progression. Notably, measuring CPE transcript levels in serum exosomes from cancer patients could have potential liquid biopsy applications.
Collapse
|
9
|
Bosch E, Hebebrand M, Popp B, Penger T, Behring B, Cox H, Towner S, Kraus C, Wilson WG, Khan S, Krumbiegel M, Ekici AB, Uebe S, Trollmann R, Woelfle J, Reis A, Vasileiou G. BDV Syndrome: An Emerging Syndrome With Profound Obesity and Neurodevelopmental Delay Resembling Prader-Willi Syndrome. J Clin Endocrinol Metab 2021; 106:3413-3427. [PMID: 34383079 DOI: 10.1210/clinem/dgab592] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Indexed: 12/17/2022]
Abstract
CONTEXT CPE encodes carboxypeptidase E, an enzyme that converts proneuropeptides and propeptide hormones to bioactive forms. It is widely expressed in the endocrine and central nervous system. To date, 4 individuals from 2 families with core clinical features including morbid obesity, neurodevelopmental delay, and hypogonadotropic hypogonadism, harboring biallelic loss-of-function (LoF) CPE variants, have been reported. OBJECTIVE We describe 4 affected individuals from 3 unrelated consanguineous families, 2 siblings of Syrian, 1 of Egyptian, and 1 of Pakistani descent, all harboring novel homozygous CPE LoF variants. METHODS After excluding Prader-Willi syndrome (PWS), exome sequencing was performed in both Syrian siblings. The variants identified in the other 2 individuals were reported as research variants in a large-scale exome study and in the ClinVar database. Computational modeling of all possible missense alterations allowed assessing CPE tolerance to missense variants. RESULTS All affected individuals were severely obese with neurodevelopmental delay and other endocrine anomalies. Three individuals from 2 families shared the same CPE homozygous truncating variant c.361C > T, p.(Arg121*), while the fourth carried the c.994del, p.(Ser333Alafs*22) variant. Comparison of clinical features with previously described cases and standardization according to the Human Phenotype Ontology terms indicated a recognizable clinical phenotype, which we termed Blakemore-Durmaz-Vasileiou (BDV) syndrome. Computational analysis indicated high conservation of CPE domains and intolerance to missense changes. CONCLUSION Biallelic truncating CPE variants are associated with BDV syndrome, a clinically recognizable monogenic recessive syndrome with childhood-onset obesity, neurodevelopmental delay, hypogonadotropic hypogonadism, and hypothyroidism. BDV syndrome resembles PWS. Our findings suggest missense variants may also be clinically relevant.
Collapse
Affiliation(s)
- Elisabeth Bosch
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Moritz Hebebrand
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Bernt Popp
- Institute of Human Genetics, University of Leipzig Hospitals and Clinics, 04103 Leipzig, Germany
| | - Theresa Penger
- Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Bettina Behring
- Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Helen Cox
- West Midlands Regional Clinical Genetics Unit, Birmingham Women's Hospital, Edgbaston, Birmingham B15 2TG, UK
| | - Shelley Towner
- Department of Pediatrics, Division of Genetics, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Cornelia Kraus
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - William G Wilson
- Department of Pediatrics, Division of Genetics, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Shagufta Khan
- West Midlands Regional Clinical Genetics Unit, Birmingham Women's Hospital, Edgbaston, Birmingham B15 2TG, UK
| | - Mandy Krumbiegel
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Arif B Ekici
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Steffen Uebe
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Regina Trollmann
- Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Joachim Woelfle
- Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, 91054 Erlangen, Germany
| | - André Reis
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Georgia Vasileiou
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| |
Collapse
|
10
|
Notaras M, Lodhi A, Fang H, Greening D, Colak D. The proteomic architecture of schizophrenia iPSC-derived cerebral organoids reveals alterations in GWAS and neuronal development factors. Transl Psychiatry 2021; 11:541. [PMID: 34667143 PMCID: PMC8526592 DOI: 10.1038/s41398-021-01664-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/24/2021] [Accepted: 09/30/2021] [Indexed: 12/21/2022] Open
Abstract
Schizophrenia (Scz) is a brain disorder that has a typical onset in early adulthood but otherwise maintains unknown disease origins. Unfortunately, little progress has been made in understanding the molecular mechanisms underlying neurodevelopment of Scz due to ethical and technical limitations in accessing developing human brain tissue. To overcome this challenge, we have previously utilized patient-derived Induced Pluripotent Stem Cells (iPSCs) to generate self-developing, self-maturating, and self-organizing 3D brain-like tissue known as cerebral organoids. As a continuation of this prior work, here we provide an architectural map of the developing Scz organoid proteome. Utilizing iPSCs from n = 25 human donors (n = 8 healthy Ctrl donors, and n = 17 Scz patients), we generated 3D cerebral organoids, employed 16-plex isobaric sample-barcoding chemistry, and simultaneously subjected samples to comprehensive high-throughput liquid-chromatography/mass-spectrometry (LC/MS) quantitative proteomics. Of 3,705 proteins identified by high-throughput proteomic profiling, we identified that just ~2.62% of the organoid global proteomic landscape was differentially regulated in Scz organoids. In sum, just 43 proteins were up-regulated and 54 were down-regulated in Scz patient-derived organoids. Notably, a range of neuronal factors were depleted in Scz organoids (e.g., MAP2, TUBB3, SV2A, GAP43, CRABP1, NCAM1 etc.). Based on global enrichment analysis, alterations in key pathways that regulate nervous system development (e.g., axonogenesis, axon development, axon guidance, morphogenesis pathways regulating neuronal differentiation, as well as substantia nigra development) were perturbed in Scz patient-derived organoids. We also identified prominent alterations in two novel GWAS factors, Pleiotrophin (PTN) and Podocalyxin (PODXL), in Scz organoids. In sum, this work serves as both a report and a resource that researchers can leverage to compare, contrast, or orthogonally validate Scz factors and pathways identified in observational clinical studies and other model systems.
Collapse
Affiliation(s)
- Michael Notaras
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Aiman Lodhi
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Haoyun Fang
- Baker Institute for Heart and Diabetes, Melbourne, VIC, Australia
| | - David Greening
- Baker Institute for Heart and Diabetes, Melbourne, VIC, Australia.
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia.
- Central Clinical School, Monash University, Melbourne, VIC, Australia.
- Baker Department of Cardiometabolic Health, University of Melbourne, Melbourne, VIC, Australia.
| | - Dilek Colak
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA.
- Gale and Ira Drukier Institute for Children's Health, Weill Cornell Medical College, Cornell University, New York, NY, USA.
| |
Collapse
|
11
|
Asadi F, Dhanvantari S. Pathways of Glucagon Secretion and Trafficking in the Pancreatic Alpha Cell: Novel Pathways, Proteins, and Targets for Hyperglucagonemia. Front Endocrinol (Lausanne) 2021; 12:726368. [PMID: 34659118 PMCID: PMC8511682 DOI: 10.3389/fendo.2021.726368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/13/2021] [Indexed: 12/15/2022] Open
Abstract
Patients with diabetes mellitus exhibit hyperglucagonemia, or excess glucagon secretion, which may be the underlying cause of the hyperglycemia of diabetes. Defective alpha cell secretory responses to glucose and paracrine effectors in both Type 1 and Type 2 diabetes may drive the development of hyperglucagonemia. Therefore, uncovering the mechanisms that regulate glucagon secretion from the pancreatic alpha cell is critical for developing improved treatments for diabetes. In this review, we focus on aspects of alpha cell biology for possible mechanisms for alpha cell dysfunction in diabetes: proglucagon processing, intrinsic and paracrine control of glucagon secretion, secretory granule dynamics, and alterations in intracellular trafficking. We explore possible clues gleaned from these studies in how inhibition of glucagon secretion can be targeted as a treatment for diabetes mellitus.
Collapse
Affiliation(s)
- Farzad Asadi
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
| | - Savita Dhanvantari
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
- Imaging Research Program, Lawson Health Research Institute, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
| |
Collapse
|
12
|
Li N, Teng SW, Zhao L, Li JR, Xu JL, Li N, Shuai JC, Chen ZY. Carboxypeptidase E Regulates Activity-Dependent TrkB Neuronal Surface Insertion and Hippocampal Memory. J Neurosci 2021; 41:6987-7002. [PMID: 34266900 PMCID: PMC8372023 DOI: 10.1523/jneurosci.0236-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/14/2021] [Accepted: 07/09/2021] [Indexed: 11/21/2022] Open
Abstract
Activity-dependent insertion of the tropomyosin-related kinase B (TrkB) receptor into the plasma membrane can explain, in part, the preferential effect of brain-derived neurotrophic factor (BDNF) on active neurons and synapses; however, the underlying molecular mechanisms remain obscure. Here, we report a novel function for carboxypeptidase E (CPE) in controlling chemical long-term potentiation stimuli-induced TrkB surface delivery in hippocampal neurons. Total internal reflection fluorescence assays and line plot assays showed that CPE facilitates TrkB transport from dendritic shafts to the plasma membrane. The Box2 domain in the juxtamembrane region of TrkB and the C terminus of CPE are critical for the activity-dependent plasma membrane insertion of TrkB. Moreover, the transactivator of transcription TAT-CPE452-466, which could block the association between CPE and TrkB, significantly inhibited neuronal activity-enhanced BDNF signaling and dendritic spine morphologic plasticity in cultured hippocampal neurons. Microinfusion of TAT-CPE452-466 into the dorsal hippocampus of male C57BL/6 mice inhibited the endogenous interaction between TrkB and CPE and diminished fear-conditioning-induced TrkB phosphorylation, which might lead to an impairment in hippocampal memory acquisition and consolidation but not retrieval. These results suggest that CPE modulates activity-induced TrkB surface insertion and hippocampal-dependent memory and sheds light on our understanding of the role of CPE in TrkB-dependent synaptic plasticity and memory modulation.SIGNIFICANCE STATEMENT It is well known that BDNF acts preferentially on active neurons; however, the underlying molecular mechanism is not fully understood. In this study, we found that the cytoplasmic tail of CPE could interact with TrkB and facilitate the neuronal activity-dependent movement of TrkB vesicles to the plasma membrane. Blocking the association between CPE and TrkB decreased fear-conditioning-induced TrkB phosphorylation and led to hippocampal memory deficits. These findings provide novel insights into the role of CPE in TrkB intracellular trafficking as well as in mediating BDNF/TrkB function in synaptic plasticity and hippocampal memory.
Collapse
Affiliation(s)
- Na Li
- Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Department of Cardiology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | | | - Ling Zhao
- Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
| | - Jing-Rui Li
- College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Institute of Biomedical Sciences, Shandong Normal University, Jinan 250014, China
| | - Jia-Ling Xu
- Institution of Traditional Chinese Medicine Innovation Research, Shandong University of Traditional Chinese Medicine, Jinan, 250355 China
| | - Na Li
- Departments of Anatomy and Neurobiology and
| | | | - Zhe-Yu Chen
- Departments of Anatomy and Neurobiology and
- Institute of Brain Science, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
- Institution of Traditional Chinese Medicine Innovation Research, Shandong University of Traditional Chinese Medicine, Jinan, 250355 China
| |
Collapse
|
13
|
Germanos M, Gao A, Taper M, Yau B, Kebede MA. Inside the Insulin Secretory Granule. Metabolites 2021; 11:metabo11080515. [PMID: 34436456 PMCID: PMC8401130 DOI: 10.3390/metabo11080515] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/03/2021] [Accepted: 08/03/2021] [Indexed: 12/19/2022] Open
Abstract
The pancreatic β-cell is purpose-built for the production and secretion of insulin, the only hormone that can remove glucose from the bloodstream. Insulin is kept inside miniature membrane-bound storage compartments known as secretory granules (SGs), and these specialized organelles can readily fuse with the plasma membrane upon cellular stimulation to release insulin. Insulin is synthesized in the endoplasmic reticulum (ER) as a biologically inactive precursor, proinsulin, along with several other proteins that will also become members of the insulin SG. Their coordinated synthesis enables synchronized transit through the ER and Golgi apparatus for congregation at the trans-Golgi network, the initiating site of SG biogenesis. Here, proinsulin and its constituents enter the SG where conditions are optimized for proinsulin processing into insulin and subsequent insulin storage. A healthy β-cell is continually generating SGs to supply insulin in vast excess to what is secreted. Conversely, in type 2 diabetes (T2D), the inability of failing β-cells to secrete may be due to the limited biosynthesis of new insulin. Factors that drive the formation and maturation of SGs and thus the production of insulin are therefore critical for systemic glucose control. Here, we detail the formative hours of the insulin SG from the luminal perspective. We do this by mapping the journey of individual members of the SG as they contribute to its genesis.
Collapse
|
14
|
Ramzy A, Kieffer TJ. Altered islet prohormone processing: A cause or consequence of diabetes? Physiol Rev 2021; 102:155-208. [PMID: 34280055 DOI: 10.1152/physrev.00008.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Peptide hormones are first produced as larger precursor prohormones that require endoproteolytic cleavage to liberate the mature hormones. A structurally conserved but functionally distinct family of nine prohormone convertase enzymes (PCs) are responsible for cleavage of protein precursors of which PC1/3 and PC2 are known to be exclusive to neuroendocrine cells and responsible for prohormone cleavage. Differential expression of PCs within tissues define prohormone processing; whereas glucagon is the major product liberated from proglucagon via PC2 in pancreatic α-cells, proglucagon is preferentially processed by PC1/3 in intestinal L cells to produce glucagon-like peptides 1 and 2 (GLP-1, GLP-2). Beyond our understanding of processing of islet prohormones in healthy islets, there is convincing evidence that proinsulin, proIAPP, and proglucagon processing is altered during prediabetes and diabetes. There is predictive value of elevated circulating proinsulin or proinsulin : C-peptide ratio for progression to type 2 diabetes and elevated proinsulin or proinsulin : C-peptide is predictive for development of type 1 diabetes in at risk groups. After onset of diabetes, patients have elevated circulating proinsulin and proIAPP and proinsulin may be an autoantigen in type 1 diabetes. Further, preclinical studies reveal that α-cells have altered proglucagon processing during diabetes leading to increased GLP-1 production. We conclude that despite strong associative data, current evidence is inconclusive on the potential causal role of impaired prohormone processing in diabetes, and suggest that future work should focus on resolving the question of whether altered prohormone processing is a causal driver or merely a consequence of diabetes pathology.
Collapse
Affiliation(s)
- Adam Ramzy
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Timothy J Kieffer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.,Department of Surgery, University of British Columbia, Vancouver, BC, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
15
|
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.
Collapse
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
| |
Collapse
|
16
|
Fukuoka H, Shichi H, Yamamoto M, Takahashi Y. The Mechanisms Underlying Autonomous Adrenocorticotropic Hormone Secretion in Cushing's Disease. Int J Mol Sci 2020; 21:ijms21239132. [PMID: 33266265 PMCID: PMC7730156 DOI: 10.3390/ijms21239132] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/21/2020] [Accepted: 11/29/2020] [Indexed: 12/16/2022] Open
Abstract
Cushing’s disease caused due to adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (ACTHomas) leads to hypercortisolemia, resulting in increased morbidity and mortality. Autonomous ACTH secretion is attributed to the impaired glucocorticoid negative feedback (glucocorticoid resistance) response. Interestingly, other conditions, such as ectopic ACTH syndrome (EAS) and non-neoplastic hypercortisolemia (NNH, also known as pseudo-Cushing’s syndrome) also exhibit glucocorticoid resistance. Therefore, to differentiate between these conditions, several dynamic tests, including those with desmopressin (DDAVP), corticotrophin-releasing hormone (CRH), and Dex/CRH have been developed. In normal pituitary corticotrophs, ACTH synthesis and secretion are regulated mainly by CRH and glucocorticoids, which are the ACTH secretion-stimulating and -suppressing factors, respectively. These factors regulate ACTH synthesis and secretion through genomic and non-genomic mechanisms. Conversely, glucocorticoid negative feedback is impaired in ACTHomas, which could be due to the overexpression of 11β-HSD2, HSP90, or TR4, or loss of expression of CABLES1 or nuclear BRG1 proteins. Genetic analysis has indicated the involvement of several genes in the etiology of ACTHomas, including USP8, USP48, BRAF, and TP53. However, the association between glucocorticoid resistance and these genes remains unclear. Here, we review the clinical aspects and molecular mechanisms of ACTHomas and compare them to those of other related conditions.
Collapse
Affiliation(s)
- Hidenori Fukuoka
- Division of Diabetes and Endocrinology, Kobe University Hospital, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan;
- Correspondence: ; Tel.: +81-78-382-5861; Fax: +81-78-382-2080
| | - Hiroki Shichi
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; (H.S.); (Y.T.)
| | - Masaaki Yamamoto
- Division of Diabetes and Endocrinology, Kobe University Hospital, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan;
| | - Yutaka Takahashi
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; (H.S.); (Y.T.)
- Department of Diabetes and Endocrinology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan
| |
Collapse
|
17
|
Yang Z, Li P, Shang Q, Wang Y, He J, Ge S, Jia R, Fan X. CRISPR-mediated BMP9 ablation promotes liver steatosis via the down-regulation of PPARα expression. SCIENCE ADVANCES 2020; 6:6/48/eabc5022. [PMID: 33246954 PMCID: PMC7695473 DOI: 10.1126/sciadv.abc5022] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 10/14/2020] [Indexed: 05/09/2023]
Abstract
Obesity drives the development of nonalcoholic fatty liver disease (NAFLD) characterized by hepatic steatosis. Several bone morphogenetic proteins (BMPs) except BMP9 were reported related to metabolic syndrome. This study demonstrates that liver cytokine BMP9 is decreased in the liver and serum of NAFLD model mice and patients. BMP9 knockdown induces lipid accumulation in Hepa 1-6 cells. BMP9-knockout mice exhibit hepatosteatosis due to down-regulated peroxisome proliferator-activated receptor α (PPARα) expression and reduced fatty acid oxidation. In vitro, recombinant BMP9 treatment attenuates triglyceride accumulation by enhancing PPARα promoter activity via the activation of p-smad. PPARα-specific antagonist GW6471 abolishes the effect of BMP9 knockdown. Furthermore, adeno-associated virus-mediated BMP9 overexpression in mouse liver markedly relieves liver steatosis and obesity-related metabolic syndrome. These findings indicate that BMP9 plays a critical role in regulating hepatic lipid metabolism in a PPARα-dependent manner and may provide a previously unknown insight into NAFLD therapeutic approaches.
Collapse
Affiliation(s)
- Z Yang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 833 Zhizaoju Road, Shanghai 200011, China
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200032, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, 833 Zhizaoju Road, Shanghai 200011, China
| | - P Li
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 833 Zhizaoju Road, Shanghai 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, 833 Zhizaoju Road, Shanghai 200011, China
| | - Q Shang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 833 Zhizaoju Road, Shanghai 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, 833 Zhizaoju Road, Shanghai 200011, China
| | - Y Wang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 833 Zhizaoju Road, Shanghai 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, 833 Zhizaoju Road, Shanghai 200011, China
| | - J He
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 833 Zhizaoju Road, Shanghai 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, 833 Zhizaoju Road, Shanghai 200011, China
| | - S Ge
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 833 Zhizaoju Road, Shanghai 200011, China.
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, 833 Zhizaoju Road, Shanghai 200011, China
| | - R Jia
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 833 Zhizaoju Road, Shanghai 200011, China.
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, 833 Zhizaoju Road, Shanghai 200011, China
| | - X Fan
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 833 Zhizaoju Road, Shanghai 200011, China.
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200032, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, 833 Zhizaoju Road, Shanghai 200011, China
| |
Collapse
|
18
|
Toxin-like neuropeptides in the sea anemone Nematostella unravel recruitment from the nervous system to venom. Proc Natl Acad Sci U S A 2020; 117:27481-27492. [PMID: 33060291 DOI: 10.1073/pnas.2011120117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The sea anemone Nematostella vectensis (Anthozoa, Cnidaria) is a powerful model for characterizing the evolution of genes functioning in venom and nervous systems. Although venom has evolved independently numerous times in animals, the evolutionary origin of many toxins remains unknown. In this work, we pinpoint an ancestral gene giving rise to a new toxin and functionally characterize both genes in the same species. Thus, we report a case of protein recruitment from the cnidarian nervous to venom system. The ShK-like1 peptide has a ShKT cysteine motif, is lethal for fish larvae and packaged into nematocysts, the cnidarian venom-producing stinging capsules. Thus, ShK-like1 is a toxic venom component. Its paralog, ShK-like2, is a neuropeptide localized to neurons and is involved in development. Both peptides exhibit similarities in their functional activities: They provoke contraction in Nematostella polyps and are toxic to fish. Because ShK-like2 but not ShK-like1 is conserved throughout sea anemone phylogeny, we conclude that the two paralogs originated due to a Nematostella-specific duplication of a ShK-like2 ancestor, a neuropeptide-encoding gene, followed by diversification and partial functional specialization. ShK-like2 is represented by two gene isoforms controlled by alternative promoters conferring regulatory flexibility throughout development. Additionally, we characterized the expression patterns of four other peptides with structural similarities to studied venom components and revealed their unexpected neuronal localization. Thus, we employed genomics, transcriptomics, and functional approaches to reveal one venom component, five neuropeptides with two different cysteine motifs, and an evolutionary pathway from nervous to venom system in Cnidaria.
Collapse
|
19
|
Sun J, Meng D, Yu T, Li F, Zhang G, Tian X, Zhao N, Li G, Li L, Wang H, Liu Y, Meng Y, Ma Y, Wan Z, Bao J, Piao H. N-terminal truncated carboxypeptidase E represses E-cadherin expression in lung cancer by stabilizing the Snail-HDAC complex. Am J Cancer Res 2020; 10:925-938. [PMID: 32266100 PMCID: PMC7136916 DOI: pmid/32266100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/16/2019] [Indexed: 02/05/2023] Open
Abstract
The N-terminal truncated carboxypeptidase E (CPEΔN) protein, an alternative splicing product of the carboxypeptidase E gene, has recently been recognized as an independent predictor for the recurrence and metastasis of lung adenocarcinoma. In this study, we showed that CPEΔN may accelerate lung cancer invasion via an E-cadherin-dependent mechanism. In vitro experiments and in vivo bioluminescence imaging assay revealed CPEΔN promoted the mobility and invasion of human lung cancer cells by suppressing endogenous expression of E-cadherin, a critical regulator for epithelial tissue homeostasis. Further mechanistic analyses revealed that CPEΔN directly interacted with and stabilized the Snail/HDAC1/HDAC3 complex within the promoter region of the E-cadherin-encoding CDH1 gene. CPEΔN overexpression led to a reduction of histone H3K9 acetylation and an increase of H3K9 and H3K27 trimethylation in the CHD1 gene promoter and ultimately inhibited E-cadherin transcription. In addition, correlations among CPEΔN, E-cadherin expression and tumor progression in 195 cases of lung adenocarcinoma patients were analyzed. Higher nuclear expression of CPEΔN was detected in patients with advanced stage of lung adenocarcinoma. Nuclear expression of CPEΔN was negatively correlated with the cell membrane expression of E-cadherin. Collectively, our findings illustrated that CPEΔN was involved in the transcriptional regulation of the epithelial-mesenchymal transition-related gene CDH1 and provide novel insights into CPEΔN-associated lung cancer metastasis.
Collapse
Affiliation(s)
- Jing Sun
- Central Laboratory, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| | - Dawei Meng
- Department of Otolaryngology Head and Neck Surgery, Liaoning Provincial Jinqiu HospitalShenyang 110016, Liaoning, China
| | - Tao Yu
- Department of Medical Imaging, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| | - Feng Li
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health of The PRC, China Medical UniversityShenyang 110122, Liaoning, China
- Key Laboratory of Medical Cell Biology, Ministry of Education of The PRC, China Medical UniversityShenyang 110122, Liaoning, China
| | - Guirong Zhang
- Central Laboratory, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| | - Xin Tian
- Molecular Oncology Laboratory of Cancer Research Institute, China Medical University First HospitalShenyang 110001, Liaoning, China
| | - Nannan Zhao
- Department of Medical Imaging, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| | - Guimin Li
- Department of Otolaryngology Head and Neck Surgery, Liaoning Provincial Jinqiu HospitalShenyang 110016, Liaoning, China
| | - Lu Li
- Research Center of Translational Medicine, The Second Affiliated Hospital of Shantou University Medical CollegeShantou 515000, Guangdong, China
| | - Hongyue Wang
- Department of Scientific Research and Academic, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| | - Yeqiu Liu
- Department of Medical Imaging, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| | - Yiming Meng
- Central Laboratory, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| | - Yushu Ma
- Central Laboratory, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| | - Zhong Wan
- Department of Scientific Research and Academic, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| | - Jimin Bao
- Department of Otolaryngology Head and Neck Surgery, Liaoning Provincial Jinqiu HospitalShenyang 110016, Liaoning, China
| | - Haozhe Piao
- Central Laboratory, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
- Department of Neurosurgery, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & InstituteShenyang 110042, Liaoning, China
| |
Collapse
|
20
|
Fan S, Gao X, Chen P, Li X. Carboxypeptidase E-ΔN promotes migration, invasiveness, and epithelial–mesenchymal transition of human osteosarcoma cells via the Wnt–β-catenin pathway. Biochem Cell Biol 2019; 97:446-453. [PMID: 30508384 DOI: 10.1139/bcb-2018-0236] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Osteosarcoma (OS) is the most common malignant bone tumor in children and adolescents, and metastatic OS is the major cause of OS-related death. Carboxypeptidase E (CPE) is known to be highly expressed in some cancer types, and its N-terminal truncated form, CPE-ΔN, is implicated in tumor metastasis and poor prognosis. In this study, we investigated the effect of CPE-ΔN on cell migration, invasiveness, and the epithelial–mesenchymal transition (EMT) of OS cells, and illustrated the molecular mechanisms. We first constructed CPE-ΔN overexpressing human OS cell lines (143B and U2OS cells), and found that ectopic CPE-ΔN expression in OS cells enhanced cell migration and invasiveness, and promoted the EMT process. Further, overexpression of CPE-ΔN increased the levels of c-myc and nuclear β-catenin in OS cells, which suggested the CPE-ΔN promotes activation of the Wnt–β-catenin pathway in OS cells. Treatment with β-catenin small interfering RNA (siRNA) inhibited the migration and invasiveness of CPE-ΔN-overexpressing cells, and reduced the expression of E-cadherin. Together, these results suggest that CPE-ΔN promotes migration, invasiveness, and the EMT of OS cells via the Wnt–β-catenin signaling pathway.
Collapse
Affiliation(s)
- Shuli Fan
- Department of Geriatrics, The First Affiliated Hospital of China Medical University, Shenyang 110001, P. R. China
| | - Xiang Gao
- Department of Orthopedic Surgery, The First Affiliated Hospital of China Medical University, Shenyang 110001, P. R. China
| | - Peng Chen
- Department of Orthopedic Surgery, The First Affiliated Hospital of China Medical University, Shenyang 110001, P. R. China
| | - Xu Li
- Department of Orthopedic Surgery, The First Affiliated Hospital of China Medical University, Shenyang 110001, P. R. China
| |
Collapse
|
21
|
Yang X, Lou H, Chen YT, Huang SF, Loh YP. A novel 40kDa N-terminal truncated carboxypeptidase E splice variant: cloning, cDNA sequence analysis and role in regulation of metastatic genes in human cancers. Genes Cancer 2019; 10:160-170. [PMID: 31798768 PMCID: PMC6872665 DOI: 10.18632/genesandcancer.193] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Carboxypeptidase E (CPE), a prohormone processing enzyme, is a 476- amino acid protein with a signal peptide in its N-terminus and is expressed in the nervous and the endocrine systems. Recent evidence indicate CPE plays various non-enzymatic roles in the endocrine and nervous systems and in various cancers. Besides wild type (WT) CPE, a 40-kDa CPE protein that localizes in the nucleus and cytoplasm has been described in embryonic mouse brain. In this study we have cloned this CPE variant encoding the 40kDa CPE-ΔN protein from human cancer cells. RACE assay and sequence analysis confirmed existence of this CPE variant mRNA, which has 198 nucleotides removed within the first exon and 589 nucleotides from the 3’-UTR, respectively, compared to WT-CPE mRNA. Bioinformatic analysis revealed that this CPE variant mRNA has a shortened open reading frame, which starts coding from the 3rd ATG relative to WT-CPE mRNA and encodes a 40kDa N-terminus truncated CPE protein. RT-PCR and Western blot analysis showed that 40kDa CPE-ΔN is expressed in multiple cancer cell lines and tumor tissues. Overexpression of this 40kDa CPE-ΔN variant up-regulated expression of multiple metastatic genes encompassing different signaling pathways, suggesting potentially an important role of CPE-ΔN in tumor metastasis.
Collapse
Affiliation(s)
- Xuyu Yang
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Hong Lou
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Ya-Ting Chen
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhuna, Miaoli, Taiwan
| | - Shui-Feng Huang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhuna, Miaoli, Taiwan.,Department of Anatomical Pathology, Chung-Shan Medical University Hospital, Taichung, Taiwan
| | - Y Peng Loh
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
22
|
Xiao L, Yang X, Loh YP. Neurotrophic, Gene Regulation, and Cognitive Functions of Carboxypeptidase E-Neurotrophic Factor-α1 and Its Variants. Front Neurosci 2019; 13:243. [PMID: 30941009 PMCID: PMC6433828 DOI: 10.3389/fnins.2019.00243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/01/2019] [Indexed: 12/13/2022] Open
Abstract
Carboxypeptidase E, also known as neurotrophic factor-α1 (CPE-NFα1), was first discovered as an exopeptidase and is known to work by cleaving C-terminal basic amino acids from prohormone intermediates to produce mature peptide hormones and neuropeptides in the endocrine and central nervous systems, respectively. CPE-NFα1 also plays a critical role in prohormone sorting and secretory vesicle transportation. Recently, emerging studies have indicated that CPE-NFα1 exerts multiple non-enzymatic physiological roles in maintaining normal central nervous system function and in neurodevelopment. This includes potent neuroprotective and anti-depressant activities, as well as stem cell differentiation functions. In addition, N-terminal truncated variants of CPE-NFα1 have been identified to regulate expression of important neurodevelopmental genes. This mini-review summarizes recent advances in understanding the mechanisms underlying CPE-NFα1’s function in neuroprotection during stress and aspects of neurodevelopment.
Collapse
Affiliation(s)
- Lan Xiao
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Xuyu Yang
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - 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
| |
Collapse
|
23
|
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: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pro-opiomelanocortin (POMC) is the archetypal polypeptide precursor of hormones and neuropeptides. In this review, we examine the variability in the individual peptides produced in different tissues and the impact of the simultaneous presence of their precursors or fragments. We also discuss the problems inherent in accurately measuring which of the precursors and their derived peptides are present in biological samples. We address how not being able to measure all the combinations of precursors and fragments quantitatively has affected our understanding of the pathophysiology associated with POMC processing. To understand how different ratios of peptides arise, we describe the role of the pro-hormone convertases (PCs) and their tissue specificities and consider the cellular processing pathways which enable regulated secretion of different peptides that play crucial roles in integrating a range of vital physiological functions. In the pituitary, correct processing of POMC peptides is essential to maintain the hypothalamic-pituitary-adrenal axis, and this processing can be disrupted in POMC-expressing tumors. In hypothalamic neurons expressing POMC, abnormalities in processing critically impact on the regulation of appetite, energy homeostasis, and body composition. More work is needed to understand whether expression of the POMC gene in a tissue equates to release of bioactive peptides. We suggest that this comprehensive view of POMC processing, with a focus on gaining a better understanding of the combination of peptides produced and their relative bioactivity, is a necessity for all involved in studying this fascinating physiological regulatory phenomenon.
Collapse
Affiliation(s)
- Erika Harno
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Thanuja Gali Ramamoorthy
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Anthony P Coll
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Anne White
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| |
Collapse
|
24
|
Notaras M, van den Buuse M. Brain-Derived Neurotrophic Factor (BDNF): Novel Insights into Regulation and Genetic Variation. Neuroscientist 2018; 25:434-454. [DOI: 10.1177/1073858418810142] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Since its discovery, brain-derived neurotrophic factor (BDNF) has spawned a literature that now spans 35 years of research. While all neurotrophins share considerable overlap in sequence homology and their processing, BDNF has become the most widely studied neurotrophin because of its broad roles in brain homeostasis, health, and disease. Although research on BDNF has produced thousands of articles, there remain numerous long-standing questions on aspects of BDNF molecular biology and signaling. Here we provide a comprehensive review, including both a historical narrative and a forward-looking perspective on advances in the actions of BDNF within the brain. We specifically review BDNF’s gene structure, peptide composition (including domains, posttranslational modifications and putative motif sites), mechanisms of transport, signaling pathway recruitment, and other recent developments including the functional effects of genetic variation and the discovery of a new BDNF prodomain ligand. This body of knowledge illustrates a highly conserved and complex role for BDNF within the brain, that promotes the idea that the neurotrophin biology of BDNF is diverse and that any disease involvement is likely to be equally multifarious.
Collapse
Affiliation(s)
- Michael Notaras
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Maarten van den Buuse
- School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
- Department of Pharmacology, University of Melbourne, Melbourne, Victoria, Australia
| |
Collapse
|
25
|
Morrison LM, Edwards SL, Manning L, Stec N, Richmond JE, Miller KG. Sentryn and SAD Kinase Link the Guided Transport and Capture of Dense Core Vesicles in Caenorhabditis elegans. Genetics 2018; 210:925-946. [PMID: 30401764 PMCID: PMC6218223 DOI: 10.1534/genetics.118.300847] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 08/27/2018] [Indexed: 11/18/2022] Open
Abstract
Dense core vesicles (DCVs) can transmit signals by releasing neuropeptides from specialized synaptic regions called active zones. DCVs reach the active zone by motorized transport through a long axon. A reverse motor frequently interrupts progress by taking DCVs in the opposite direction. "Guided transport" refers to the mechanism by which outward movements ultimately dominate to bring DCVs to the synaptic region. After guided transport, DCVs alter their interactions with motors and enter a "captured" state. The mechanisms of guided transport and capture of DCVs are unknown. Here, we discovered two proteins that contribute to both processes in Caenorhabditis elegans SAD kinase and a novel conserved protein we named Sentryn are the first proteins found to promote DCV capture. By imaging DCVs moving in various regions of single identified neurons in living animals, we found that DCV guided transport and capture are linked through SAD kinase, Sentryn, and Liprin-α. These proteins act together to regulate DCV motorized transport in a region-specific manner. Between the cell body and the synaptic region, they promote forward transport. In the synaptic region, where all three proteins are highly enriched at active zones, they promote DCV pausing by inhibiting transport in both directions. These three proteins appear to be part of a special subset of active zone-enriched proteins because other active zone proteins do not share their unique functions.
Collapse
Affiliation(s)
- Logan M Morrison
- Genetic Models of Disease Laboratory, Oklahoma Medical Research Foundation, Oklahoma 73104
| | - Stacey L Edwards
- Genetic Models of Disease Laboratory, Oklahoma Medical Research Foundation, Oklahoma 73104
| | - Laura Manning
- Department of Biological Sciences, University of Illinois at Chicago, Illinois 60607
| | - Natalia Stec
- Genetic Models of Disease Laboratory, Oklahoma Medical Research Foundation, Oklahoma 73104
| | - Janet E Richmond
- Department of Biological Sciences, University of Illinois at Chicago, Illinois 60607
| | - Kenneth G Miller
- Genetic Models of Disease Laboratory, Oklahoma Medical Research Foundation, Oklahoma 73104
| |
Collapse
|
26
|
Xiao L, Yang X, Sharma VK, Loh YP. Cloning, gene regulation, and neuronal proliferation functions of novel N-terminal-truncated carboxypeptidase E/neurotrophic factor-αl variants in embryonic mouse brain. FASEB J 2018; 33:808-820. [PMID: 30063439 DOI: 10.1096/fj.201800359r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Carboxypeptidase E (CPE), an exopeptidase involved in proneuropeptide processing, is also a neurotrophic factor, named neurotrophic factor-α1 (NF-α1) and has important roles in neuroprotection, stem cell differentiation, and neurite outgrowth, independent of enzymatic activity. Additionally, an N-terminal-truncated CPE/NF-α1 variant, (CPE/NF-α1)-ΔN, proposed from bioinformatic analysis of GenBank (National Center for Biotechnology Information, Bethesda, MD, USA) DNA sequences and encoding a 40-kDa protein, has been found to be exclusively expressed in embryonic neurons. To investigate the function of (CPE/NF-α1)-ΔN in neurodevelopment, we first cloned (CPE/NF-α1)-ΔN transcripts from an embryonic mouse brain. A rapid amplification of cDNA ends assay, DNA sequencing, and Northern blot revealed 1.9- and 1.73-kb transcripts, which encoded 47- and 40-kDa (CPE/NF-α1)-ΔN proteins, respectively. Those proteins were expressed in embryonic mouse brain. Expression of the 2 (CPE/NF-α1)-ΔN mRNAs surged at embryonic d 10.5, correlating with the time of neurogenesis in the developing brain and also at postnatal d 1. HT22 cells, a mouse hippocampal cell line, transduced with 40 kDa (CPE/NF-α1)-ΔN up-regulated expression of genes involved in embryonic neurodevelopment: insulin-like growth factor binding protein 2 ( IGFBP2), death-associated protein 1, and ephrin A1, which regulate proliferation, programmed cell death, and neuronal migration, respectively. HT22 cells and embryonic cortical neurons overexpressing 40 kDa (CPE/NF-α1)-ΔN exhibited enhanced proliferation, which was inhibited by IGFBP2 short interfering RNA treatment. Thus, 40 kDa (CPE/NF-α1)-ΔN has an important, enzymatically independent role in the regulation of genes critical for neurodevelopment.-Xiao, L., Yang, X., Sharma, V. K., Loh, Y. P. Cloning, gene regulation, and neuronal proliferation functions of novel N-terminal-truncated carboxypeptidase E/neurotrophic factor-αl variants in embryonic mouse brain.
Collapse
Affiliation(s)
- Lan Xiao
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Xuyu Yang
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Vinay Kumar Sharma
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Y Peng Loh
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
27
|
Maeda Y, Kudo S, Tsushima K, Sato E, Kubota C, Kayamori A, Bochimoto H, Koga D, Torii S, Gomi H, Watanabe T, Hosaka M. Impaired Processing of Prohormones in Secretogranin III-Null Mice Causes Maladaptation to an Inadequate Diet and Stress. Endocrinology 2018; 159:1213-1227. [PMID: 29281094 DOI: 10.1210/en.2017-00636] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 12/15/2017] [Indexed: 11/19/2022]
Abstract
Secretogranin III (SgIII), a member of the granin family, binds both to another granin, chromogranin A (CgA), and to a cholesterol-rich membrane that is destined for secretory granules (SGs). The knockdown of SgIII in adrenocorticotropic hormone (ACTH)-producing AtT-20 cells largely impairs the regulated secretion of CgA and ACTH. To clarify the physiological roles of SgIII in vivo, we analyzed hormone secretion and SG biogenesis in newly established SgIII-knockout (KO) mice. Although the SgIII-KO mice were viable and fertile and exhibited no overt abnormalities under ordinary rearing conditions, a high-fat/high-sucrose diet caused pronounced obesity in the mice. Furthermore, in the SgIII-KO mice compared with wild-type (WT) mice, the stimulated secretion of active insulin decreased substantially, whereas the storage of proinsulin increased in the islets. The plasma ACTH was also less elevated in the SgIII-KO mice than in the WT mice after chronic restraint stress, whereas the storage level of the precursor proopiomelanocortin in the pituitary gland was somewhat increased. These findings suggest that the lack of SgIII causes maladaptation of endocrine cells to an inadequate diet and stress by impairing the proteolytic conversion of prohormones in SGs, whereas SG biogenesis and the basal secretion of peptide hormones under ordinary conditions are ensured by the compensatory upregulation of other residual granins or factors.
Collapse
Affiliation(s)
- Yoshinori Maeda
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Saki Kudo
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Ken Tsushima
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Eri Sato
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Chisato Kubota
- Biosignal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Aika Kayamori
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Hiroki Bochimoto
- Health Care Administration Center, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Daisuke Koga
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan
| | - Seiji Torii
- Biosignal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Tsuyoshi Watanabe
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan
| | - Masahiro Hosaka
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| |
Collapse
|
28
|
Klein T, Eckhard U, Dufour A, Solis N, Overall CM. Proteolytic Cleavage-Mechanisms, Function, and "Omic" Approaches for a Near-Ubiquitous Posttranslational Modification. Chem Rev 2017; 118:1137-1168. [PMID: 29265812 DOI: 10.1021/acs.chemrev.7b00120] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Proteases enzymatically hydrolyze peptide bonds in substrate proteins, resulting in a widespread, irreversible posttranslational modification of the protein's structure and biological function. Often regarded as a mere degradative mechanism in destruction of proteins or turnover in maintaining physiological homeostasis, recent research in the field of degradomics has led to the recognition of two main yet unexpected concepts. First, that targeted, limited proteolytic cleavage events by a wide repertoire of proteases are pivotal regulators of most, if not all, physiological and pathological processes. Second, an unexpected in vivo abundance of stable cleaved proteins revealed pervasive, functionally relevant protein processing in normal and diseased tissue-from 40 to 70% of proteins also occur in vivo as distinct stable proteoforms with undocumented N- or C-termini, meaning these proteoforms are stable functional cleavage products, most with unknown functional implications. In this Review, we discuss the structural biology aspects and mechanisms of catalysis by different protease classes. We also provide an overview of biological pathways that utilize specific proteolytic cleavage as a precision control mechanism in protein quality control, stability, localization, and maturation, as well as proteolytic cleavage as a mediator in signaling pathways. Lastly, we provide a comprehensive overview of analytical methods and approaches to study activity and substrates of proteolytic enzymes in relevant biological models, both historical and focusing on state of the art proteomics techniques in the field of degradomics research.
Collapse
Affiliation(s)
- Theo Klein
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
| | - Ulrich Eckhard
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
| | - Antoine Dufour
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
| | - Nestor Solis
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
| | - Christopher M Overall
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
| |
Collapse
|
29
|
Abstract
The hypothalamus is an evolutionarily conserved brain structure that regulates an organism's basic functions, such as homeostasis and reproduction. Several hypothalamic nuclei and neuronal circuits have been the focus of many studies seeking to understand their role in regulating these basic functions. Within the hypothalamic neuronal populations, the arcuate melanocortin system plays a major role in controlling homeostatic functions. The arcuate pro-opiomelanocortin (POMC) neurons in particular have been shown to be critical regulators of metabolism and reproduction because of their projections to several brain areas both in and outside of the hypothalamus, such as autonomic regions of the brain stem and spinal cord. Here, we review and discuss the current understanding of POMC neurons from their development and intracellular regulators to their physiological functions and pathological dysregulation.
Collapse
Affiliation(s)
- Chitoku Toda
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520; .,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Anna Santoro
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520; .,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Jung Dae Kim
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520; .,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Sabrina Diano
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520; .,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut 06520.,Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520.,Section of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut 06520
| |
Collapse
|
30
|
Plá V, Barranco N, Pozas E, Aguado F. Amyloid-β Impairs Vesicular Secretion in Neuronal and Astrocyte Peptidergic Transmission. Front Mol Neurosci 2017; 10:202. [PMID: 28701919 PMCID: PMC5487408 DOI: 10.3389/fnmol.2017.00202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/08/2017] [Indexed: 12/17/2022] Open
Abstract
Regulated secretion of neuropeptides and neurotrophic factors critically modulates function and plasticity of synapses and circuitries. It is believed that rising amyloid-β (Aβ) concentrations, synaptic dysfunction and network disorganization underlie early phases of Alzheimer’s disease (AD). Here, we analyze the impact of soluble Aβ1–42 assemblies on peptidergic secretion in cortical neurons and astrocytes. We show that neurons and astrocytes differentially produce and release carboxypeptidase E (CPE) and secretogranin III (SgIII), two dense-core vesicle (DCV) markers belonging to the regulated secretory pathway. Importantly, Aβ1–42, but not scrambled Aβ1–42, dramatically impairs basal and Ca2+-regulated secretions of endogenously produced CPE and SgIII in cultured neurons and astrocytes. Additionally, KCl-evoked secretion of the DCV cargo brain-derived neurotrophic factor (BDNF) is lowered by Aβ1–42 administration, whereas glutamate release from synaptic vesicle (SVs) remains unchanged. In agreement with cell culture results, Aβ1–42 effects on CPE and SgIII secretion are faithfully recapitulated in acute adult brain slices. These results demonstrate that neuronal and astrocyte secretion of DCV cargos is impaired by Aβ in vitro and in situ. Furthermore, Aβ-induced dysregulated peptidergic transmission could have an important role in the pathogenesis of AD and DCV cargos are possible candidates as cerebrospinal fluid (CSF) biomarkers.
Collapse
Affiliation(s)
- Virginia Plá
- Department of Cell Biology, Physiology and Immunology, University of BarcelonaBarcelona, Spain.,Institute of Neurosciences, University of BarcelonaBarcelona, Spain
| | - Neus Barranco
- Department of Cell Biology, Physiology and Immunology, University of BarcelonaBarcelona, Spain.,Institute of Neurosciences, University of BarcelonaBarcelona, Spain
| | - Esther Pozas
- Department of Cell Biology, Physiology and Immunology, University of BarcelonaBarcelona, Spain
| | - Fernando Aguado
- Department of Cell Biology, Physiology and Immunology, University of BarcelonaBarcelona, Spain.,Institute of Neurosciences, University of BarcelonaBarcelona, Spain
| |
Collapse
|
31
|
Polastri L, Galbiati F, Folli F, Davalli AM. Effects of Carboxypeptidase E Overexpression on Insulin mRNA Levels, Regulated Insulin Secretion, and Proinsulin Processing of Pituitary GH3 Cells Transfected with a Furin-Cleavable Human Proinsulin cDNA. Cell Transplant 2017. [DOI: 10.3727/000000002783985260] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We recently developed two rat pituitary GH3 cell clones engineered to secrete human insulin (InsGH3). InsGH3 cells convert proinsulin into mature insulin, which is partially stored into a readily releasable pool of secretory granules. The efficiency of these processes, however, is relatively low in these cells, either in vitro or in vivo. This study was aimed at determining whether carboxypeptidase E (Cpe) overexpression can increase proinsulin processing and regulated secretion by InsGH3 clones. Indeed, in its membrane-bound form Cpe works as sorting receptor for the regulated secretory pathway of many hormones while, in its soluble form, Cpe takes part to the late step of insulin maturation. We obtained two Cpe-overexpressing cell lines from two different InsGH3 clones (InsGH3/C1 and C7). In the Cpe-overexpressing cell lines, derived from InsGH3 of clone 1 (InsGH3/C1-HACpe), in which the membrane-bound form of exogenous Cpe is accounted for by 90% of total Cpe immunoreactivity, we observed an increase in proinsulin gene expression, and in basal and stimulated insulin secretion compared with the original clone. In contrast, in the Cpe-overexpressing cell line derived from InsGH3 of clone 7 (InsGH3/C7-HACpe), where the exogenous membrane-bound form was only 60% of total Cpe, we detected a decrease in basal insulin release and a modest, albeit significant, increase in intracellular proinsulin processing. In conclusion, Cpe overexpression can increase regulated insulin secretion and proinsulin processing in InsGH3 cells; however, such improvements appear quantitatively and qualitatively modest.
Collapse
Affiliation(s)
- Luca Polastri
- Department of Medicine, San Raffaele Scientific Institute, Milan, Italy
| | | | - Franco Folli
- Department of Unit for Metabolic Diseases, San Raffaele Scientific Institute, Milan, Italy
| | | |
Collapse
|
32
|
Ji L, Wu HT, Qin XY, Lan R. Dissecting carboxypeptidase E: properties, functions and pathophysiological roles in disease. Endocr Connect 2017; 6:R18-R38. [PMID: 28348001 PMCID: PMC5434747 DOI: 10.1530/ec-17-0020] [Citation(s) in RCA: 42] [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] [Received: 03/22/2017] [Accepted: 03/27/2017] [Indexed: 01/02/2023]
Abstract
Since discovery in 1982, carboxypeptidase E (CPE) has been shown to be involved in the biosynthesis of a wide range of neuropeptides and peptide hormones in endocrine tissues, and in the nervous system. This protein is produced from pro-CPE and exists in soluble and membrane forms. Membrane CPE mediates the targeting of prohormones to the regulated secretory pathway, while soluble CPE acts as an exopeptidase and cleaves C-terminal basic residues from peptide intermediates to generate bioactive peptides. CPE also participates in protein internalization, vesicle transport and regulation of signaling pathways. Therefore, in two types of CPE mutant mice, Cpefat/Cpefat and Cpe knockout, loss of normal CPE leads to a lot of disorders, including diabetes, hyperproinsulinemia, low bone mineral density and deficits in learning and memory. In addition, the potential roles of CPE and ΔN-CPE, an N-terminal truncated form, in tumorigenesis and diagnosis were also addressed. Herein, we focus on dissecting the pathophysiological roles of CPE in the endocrine and nervous systems, and related diseases.
Collapse
Affiliation(s)
- Lin Ji
- Department of Cell Biology & Medical GeneticsSchool of Medicine, Shenzhen University, Shenzhen, China
| | - Huan-Tong Wu
- Beijing Engineering Research Center of Food Environment and HealthCollege of Life & Environmental Sciences, Minzu University of China, Beijing, China
| | - Xiao-Yan Qin
- Beijing Engineering Research Center of Food Environment and HealthCollege of Life & Environmental Sciences, Minzu University of China, Beijing, China
| | - Rongfeng Lan
- Department of Cell Biology & Medical GeneticsSchool of Medicine, Shenzhen University, Shenzhen, China
| |
Collapse
|
33
|
Determinants for selective transport of exogenously expressed cargo proteins into regulated and constitutive secretory pathways. J Oral Biosci 2017. [DOI: 10.1016/j.job.2017.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
34
|
Akparov V, Timofeev V, Khaliullin I, Švedas V, Kuranova I. Structure of the carboxypeptidase B complex with N-sulfamoyl-L-phenylalanine – a transition state analog of non-specific substrate. J Biomol Struct Dyn 2017; 36:956-965. [DOI: 10.1080/07391102.2017.1304242] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Valery Akparov
- Protein Chemistry Department, State Research Institute for Genetics and Selection of Industrial Microorganisms, 1-yi DorozhnyiProezd 1, Moscow, 117545, Russia
| | - Vladimir Timofeev
- X-ray Analysis Methods and Synchrotron Radiation Laboratory, Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskii Prospect 59, Moscow, 119333, Russia
- NBICS Center, National Research Centre ‘Kurchatov Institute’, Akad. Kurchatov Sq. 1, Moscow, 123182, Russia
| | - Ilyas Khaliullin
- Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology (State University), 9 Institutsky per. Dolgoprudny, Moscow, 141700, Russia
| | - Vytas Švedas
- Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 1/40Leninskie Gory, Moscow, 119991, Russia
| | - Inna Kuranova
- X-ray Analysis Methods and Synchrotron Radiation Laboratory, Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskii Prospect 59, Moscow, 119333, Russia
- NBICS Center, National Research Centre ‘Kurchatov Institute’, Akad. Kurchatov Sq. 1, Moscow, 123182, Russia
| |
Collapse
|
35
|
Xiao L, Chang SY, Xiong ZG, Selveraj P, Peng Loh Y. Absence of Carboxypeptidase E/Neurotrophic Factor-Α1 in Knock-Out Mice Leads to Dysfunction of BDNF-TRKB Signaling in Hippocampus. J Mol Neurosci 2017; 62:79-87. [PMID: 28386642 DOI: 10.1007/s12031-017-0914-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/29/2017] [Indexed: 12/12/2022]
Abstract
Carboxypeptidase E (CPE), first discovered as a prohormone processing enzyme, has also now been shown to be a secreted neurotrophic factor (neurotrophic factor-α1, NF-α1) that acts extracellularly as a signaling molecule to mediate neuroprotection, cortical stem cell differentiation, and antidepressive-like behavior in mice. Since brain-derived neurotrophic factor (BDNF) has very similar trophic functions, and its processing from pro-BDNF involves intracellular sorting of pro-BDNF to the regulated secretory pathway by CPE acting as a sorting receptor, we investigated whether the lack of CPE/NF-α1 would affect BDNF-TrkB signaling in mice. Previous studies have shown that CPE/NF-α1 knock-out (KO) mice exhibited severe neurodegeneration of the hippocampal CA3 region which raises the question of why other neurotrophic factors such as BDNF could not compensate for the deficiency of CPE. Here, we show that the expressions of pro-BDNF mRNA and protein in hippocampus of CPE-KO mice were similar to WT mice, but mature BDNF was ∼40% less in the CPE-KO mice, suggesting decreased intracellular processing of pro-BDNF. Furthermore, TrkB receptor levels were similar in both genotypes, but there was significantly decreased phosphorylation of TrkB receptor in the CPE-KO mice. Electrophysiological studies showed lack of formation of long-term potentiation in hippocampal slices of CPE-KO mice compared to WT mice, which was not rescued by application of BDNF, indicating dysfunction of the BDNF-TrkB signaling system. The CPE-KO mice showed normal postsynaptic AMPA response to kainate application in hippocampal slices and dissociated neurons. Our findings indicate that CPE/NF-α1 is essential for normal BDNF-TrkB signaling function in mouse hippocampus.
Collapse
Affiliation(s)
- Lan Xiao
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 49, Convent Drive, Bldg 49, Rm 6A-10, NICHD, NIH, Bethesda, MD, 20892, USA
| | - Su-Youne Chang
- Department of Neurologic Surgery and Physiology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Zhi-Gang Xiong
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Prabhuanand Selveraj
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 49, Convent Drive, Bldg 49, Rm 6A-10, NICHD, NIH, Bethesda, MD, 20892, USA
| | - Y Peng Loh
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 49, Convent Drive, Bldg 49, Rm 6A-10, NICHD, NIH, Bethesda, MD, 20892, USA.
| |
Collapse
|
36
|
Selvaraj P, Xiao L, Lee C, Murthy SRK, Cawley NX, Lane M, Merchenthaler I, Ahn S, Loh YP. Neurotrophic Factor-α1: A Key Wnt-β-Catenin Dependent Anti-Proliferation Factor and ERK-Sox9 Activated Inducer of Embryonic Neural Stem Cell Differentiation to Astrocytes in Neurodevelopment. Stem Cells 2016; 35:557-571. [PMID: 27709799 DOI: 10.1002/stem.2511] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 08/08/2016] [Accepted: 09/06/2016] [Indexed: 12/31/2022]
Abstract
Embryonic neurodevelopment involves inhibition of proliferation of multipotent neural stem cells (NSCs) followed by differentiation into neurons, astrocytes and oligodendrocytes to form the brain. We have identified a new neurotrophic factor, NF-α1, which inhibits proliferation and promotes differentiation of NSC/progenitors derived from E13.5 mouse cortex. Inhibition of proliferation of these cells was mediated through negatively regulating the Wnt pathway and decreasing β-catenin. NF-α1 induced differentiation of NSCs to astrocytes by enhancing Glial Fibrillary Acidic Protein (GFAP) expression through activating the ERK1/2-Sox9 signaling pathway. Cultured E13.5 cortical stem cells from NF-α1-knockout mice showed decreased astrocyte numbers compared to wild-type mice, which was rescued by treatment with NF-α1. In vivo, immunocytochemistry of brain sections and Western blot analysis of neocortex of mice showed a gradual increase of NF-α1 expression from E14.5 to P1 and a surge of GFAP expression at P1, the time of increase in astrogenesis. Importantly, NF-α1-Knockout mice showed ∼49% fewer GFAP positive astrocytes in the neocortex compared to WT mice at P1. Thus, NF-α1 is critical for regulating antiproliferation and cell fate determination, through differentiating embryonic stem cells to GFAP-positive astrocytes for normal neurodevelopment. Stem Cells 2017;35:557-571.
Collapse
Affiliation(s)
| | - Lan Xiao
- Section on Cellular Neurobiology, Bethesda, Maryland, USA
| | - Cheol Lee
- Unit on Developmental Neurogenetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Niamh X Cawley
- Section on Cellular Neurobiology, Bethesda, Maryland, USA
| | - Malcolm Lane
- Department of Epidemiology and Public Health and Anatomy and Neurobiology, University of Maryland, Baltimore, Maryland, USA
| | - Istvan Merchenthaler
- Department of Epidemiology and Public Health and Anatomy and Neurobiology, University of Maryland, Baltimore, Maryland, USA
| | - Sohyun Ahn
- Unit on Developmental Neurogenetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Y Peng Loh
- Section on Cellular Neurobiology, Bethesda, Maryland, USA
| |
Collapse
|
37
|
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.
Collapse
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
| |
Collapse
|
38
|
Mizutani A, Inoko H, Tanaka M. Carboxypeptidase E, Identified As a Direct Interactor of Growth Hormone, Is Important for Efficient Secretion of the Hormone. Mol Cells 2016; 39:756-761. [PMID: 27788574 PMCID: PMC5104884 DOI: 10.14348/molcells.2016.0183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/09/2016] [Accepted: 09/22/2016] [Indexed: 11/27/2022] Open
Abstract
We have identified 88 interactor candidates for human growth hormone (GH) by the yeast two-hybrid assay. Among those, we focused our efforts on carboxypeptidase E (CPE), which has been thought to play a key role in sorting prohormones, such as pro-opiomelanocortin (POMC), to regulated secretory vesicles. We found that CPE co-localizes with and interacts with GH in AtT20 pituitary cells. Downregulation of CPE led to decreased levels of GH secretion, consistent with involvement of CPE in GH sorting/secretion. Our binding assay in vitro with bacterially expressed proteins suggested that GH directly interacts with CPE but in a manner different from POMC.
Collapse
Affiliation(s)
- Akiko Mizutani
- Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Isehara, Kanagawa 259-1193,
Japan
- Faculty of Health and Medical Science, Teikyo Heisei University, Higashi-Ikebukuro, Toshima, Tokyo 170-8445,
Japan
| | - Hidetoshi Inoko
- Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Isehara, Kanagawa 259-1193,
Japan
| | - Masafumi Tanaka
- Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Isehara, Kanagawa 259-1193,
Japan
| |
Collapse
|
39
|
Carboxypeptidase E (CPE) inhibits the secretion and activity of Wnt3a. Oncogene 2016; 35:6416-6428. [DOI: 10.1038/onc.2016.173] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 02/26/2016] [Accepted: 04/08/2016] [Indexed: 12/19/2022]
|
40
|
Cawley NX, Li Z, Loh YP. 60 YEARS OF POMC: Biosynthesis, trafficking, and secretion of pro-opiomelanocortin-derived peptides. J Mol Endocrinol 2016; 56:T77-97. [PMID: 26880796 PMCID: PMC4899099 DOI: 10.1530/jme-15-0323] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 02/15/2016] [Indexed: 12/15/2022]
Abstract
Pro-opiomelanocortin (POMC) is a prohormone that encodes multiple smaller peptide hormones within its structure. These peptide hormones can be generated by cleavage of POMC at basic residue cleavage sites by prohormone-converting enzymes in the regulated secretory pathway (RSP) of POMC-synthesizing endocrine cells and neurons. The peptides are stored inside the cells in dense-core secretory granules until released in a stimulus-dependent manner. The complexity of the regulation of the biosynthesis, trafficking, and secretion of POMC and its peptides reflects an impressive level of control over many factors involved in the ultimate role of POMC-expressing cells, that is, to produce a range of different biologically active peptide hormones ready for action when signaled by the body. From the discovery of POMC as the precursor to adrenocorticotropic hormone (ACTH) and β-lipotropin in the late 1970s to our current knowledge, the understanding of POMC physiology remains a monumental body of work that has provided insight into many aspects of molecular endocrinology. In this article, we describe the intracellular trafficking of POMC in endocrine cells, its sorting into dense-core secretory granules and transport of these granules to the RSP. Additionally, we review the enzymes involved in the maturation of POMC to its various peptides and the mechanisms involved in the differential processing of POMC in different cell types. Finally, we highlight studies pertaining to the regulation of ACTH secretion in the anterior and intermediate pituitary and POMC neurons of the hypothalamus.
Collapse
Affiliation(s)
- Niamh X Cawley
- Section on Cellular NeurobiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Zhaojin Li
- Section on Cellular NeurobiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Y Peng Loh
- Section on Cellular NeurobiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
41
|
Huang SF, Wu HDI, Chen YT, Murthy SRK, Chiu YT, Chang Y, Chang IC, Yang X, Loh YP. Carboxypeptidase E is a prediction marker for tumor recurrence in early-stage hepatocellular carcinoma. Tumour Biol 2016; 37:9745-53. [PMID: 26803519 DOI: 10.1007/s13277-016-4814-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 01/06/2016] [Indexed: 11/28/2022] Open
Abstract
Tumor recurrence and metastasis are the major causes of death for hepatocellular carcinoma (HCC) patients who are able to receive curative resection. Identifying the predicting biomarkers for tumor recurrence would improve their survival. RNA extracted from fresh frozen tumors and adjacent non-tumor liver tissues of 120 HCC patients were obtained from Taiwan Liver Cancer Network (TLCN) in year 2010 for determination of the carboxypeptidase E (CPE) expression level (including its splicing mutant CPE-ΔN) in the tumor tissue (T) and paired non-tumor liver tissue (N) by real-time quantitative polymerase chain reaction. All patients were male, had chronic hepatitis B virus infection, were in the early pathology stage, and received curative resection. The T/N ratio of the CPE expression level was correlated with the updated survival data from TLCN in 2015. The CPE expression level in the 120 HCC patients was divided into three groups according to the T/N ratio: <1, ≥1 and ≤2, and >2, respectively. By multivariate analyses, the recurrence-free survival (RFS) was only significantly associated with the pathology stage and the CPE expression level. For overall survival (OS), only the CPE expression level was the significant prognostic factor. The CPE expression level was also significantly correlated with the tumor recurrence for both stage I (p = 0.0106) and stage II patients (p = 0.0006). The CPE mRNA expression level in HCC can be a useful biomarker for predicting tumor recurrence in HCC patients who are in the early pathology stage and able to receive curative resection.
Collapse
Affiliation(s)
- Shiu-Feng Huang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhuna, Miaoli, 350, Taiwan. .,Department of Anatomical Pathology, Chung-Shan Medical University Hospital, Taichung, Taiwan.
| | - Hong-Dar Isaac Wu
- Department of Applied Mathematics and Institute of Statistics, National Chung-Hsing University, Taichung, Taiwan
| | - Ya-Ting Chen
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhuna, Miaoli, 350, Taiwan
| | - Saravana R K Murthy
- Section on Cellular Neurobiology, Program on Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bldg. 49, Rm. 6A-10, 49, Convent Drive, Bethesda, MD, 20892, USA
| | - Yu-Ting Chiu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhuna, Miaoli, 350, Taiwan
| | - Yu Chang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhuna, Miaoli, 350, Taiwan
| | - Il-Chi Chang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhuna, Miaoli, 350, Taiwan
| | - Xuyu Yang
- Section on Cellular Neurobiology, Program on Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bldg. 49, Rm. 6A-10, 49, Convent Drive, Bethesda, MD, 20892, USA
| | - Y Peng Loh
- Section on Cellular Neurobiology, Program on Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bldg. 49, Rm. 6A-10, 49, Convent Drive, Bethesda, MD, 20892, USA.
| |
Collapse
|
42
|
Cawley NX, Rathod T, Young S, Lou H, Birch N, Loh YP. Carboxypeptidase E and Secretogranin III Coordinately Facilitate Efficient Sorting of Proopiomelanocortin to the Regulated Secretory Pathway in AtT20 Cells. Mol Endocrinol 2015; 30:37-47. [PMID: 26646096 DOI: 10.1210/me.2015-1166] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Proopiomelanocortin (POMC) is a multivalent prohormone that can be processed into at least 7 biologically active peptide hormones. Processing can begin in the trans-Golgi network (TGN) and continues in the secretory granules of the regulated secretory pathway (RSP). Sorting of POMC into these granules is a complex process. Previously, a membrane-associated form of carboxypeptidase E (CPE) was shown to bind to POMC and facilitate its trafficking into these granules. More recently, secretogranin III (SgIII) was also found to affect POMC trafficking. Here, we show by RNA silencing that CPE and SgIII play a synergistic role in the trafficking of POMC to granules of the RSP in AtT20 cells. Reduction of either protein resulted in increased constitutive secretion of POMC and chromogranin A, which was increased even further when both proteins were reduced together, indicative of missorting at the TGN. In SgIII-reduced cells, POMC accumulated in a compartment that cofractionated and colocalized with syntaxin 6, a marker of the TGN, on sucrose density gradients and in immunocytochemistry, respectively, indicating an accumulation of this protein in the presumed sorting compartment. Regulated secretion of ACTH, as a measure of sorting and processing of POMC in mature granules, was reduced in the SgIII down-regulated cells but was increased in the CPE down-regulated cells. These results suggest that multiple sorting systems exist, providing redundancy to ensure the important task of continuous and accurate trafficking of prohormones to the granules of the RSP for the production of peptide hormones.
Collapse
Affiliation(s)
- Niamh X Cawley
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Trushar Rathod
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Sigrid Young
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Hong Lou
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Nigel Birch
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| | - Y Peng Loh
- Section on Cellular Neurobiology (N.X.C., T.R., S.Y., H.L., Y.P.L.), Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480; and School of Biological Sciences (N.B.), Centre for Brain Research and Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland, New Zealand
| |
Collapse
|
43
|
Baum BJ, Alevizos I, Chiorini JA, Cotrim AP, Zheng C. Advances in salivary gland gene therapy - oral and systemic implications. Expert Opin Biol Ther 2015; 15:1443-54. [PMID: 26149284 DOI: 10.1517/14712598.2015.1064894] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Much research demonstrates the feasibility and efficacy of gene transfer to salivary glands. Recently, the first clinical trial targeting a salivary gland was completed, yielding positive safety and efficacy results. AREAS COVERED There are two major disorders affecting salivary glands: radiation damage following treatment for head and neck cancers and Sjögren's syndrome (SS). Salivary gland gene transfer has also been employed in preclinical studies using transgenic secretory proteins for exocrine (upper gastrointestinal tract) and endocrine (systemic) applications. EXPERT OPINION Salivary gland gene transfer is safe and can be beneficial in humans. Applications to treat and prevent radiation damage show considerable promise. A first-in-human clinical trial for the former was recently successfully completed. Studies on SS suffer from an inadequate understanding of its etiology. Proof of concept in animal models has been shown for exocrine and endocrine disorders. Currently, the most promising exocrine application is for the management of obesity. Endocrine applications are limited, as it is currently impossible to predict if systemically required transgenic proteins will be efficiently secreted into the bloodstream. This results from not understanding how secretory proteins are sorted. Future studies will likely employ ultrasound-assisted and pseudotyped adeno-associated viral vector-mediated gene transfer.
Collapse
Affiliation(s)
- Bruce J Baum
- a National Institute of Dental and Craniofacial Research, National Institutes of Health, Molecular Physiology and Therapeutics Branch , Bethesda, MD 20892-1190, USA
| | - Ilias Alevizos
- a National Institute of Dental and Craniofacial Research, National Institutes of Health, Molecular Physiology and Therapeutics Branch , Bethesda, MD 20892-1190, USA
| | - John A Chiorini
- a National Institute of Dental and Craniofacial Research, National Institutes of Health, Molecular Physiology and Therapeutics Branch , Bethesda, MD 20892-1190, USA
| | - Ana P Cotrim
- a National Institute of Dental and Craniofacial Research, National Institutes of Health, Molecular Physiology and Therapeutics Branch , Bethesda, MD 20892-1190, USA
| | - Changyu Zheng
- a National Institute of Dental and Craniofacial Research, National Institutes of Health, Molecular Physiology and Therapeutics Branch , Bethesda, MD 20892-1190, USA
| |
Collapse
|
44
|
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。
Collapse
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
| |
Collapse
|
45
|
Gomi H, Morikawa S, Shinmura N, Moki H, Yasui T, Tsukise A, Torii S, Watanabe T, Maeda Y, Hosaka M. Expression of Secretogranin III in Chicken Endocrine Cells: Its Relevance to the Secretory Granule Properties of Peptide Prohormone Processing and Bioactive Amine Content. J Histochem Cytochem 2015; 63:350-66. [PMID: 25673289 PMCID: PMC4409946 DOI: 10.1369/0022155415575032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/05/2015] [Indexed: 01/27/2023] Open
Abstract
The expression of secretogranin III (SgIII) in chicken endocrine cells has not been investigated. There is limited data available for the immunohistochemical localization of SgIII in the brain, pituitary, and pancreatic islets of humans and rodents. In the present study, we used immunoblotting to reveal the similarities between the expression patterns of SgIII in the common endocrine glands of chickens and rats. The protein-protein interactions between SgIII and chromogranin A (CgA) mediate the sorting of CgA/prohormone core aggregates to the secretory granule membrane. We examined these interactions using co-immunoprecipitation in chicken endocrine tissues. Using immunohistochemistry, we also examined the expression of SgIII in a wide range of chicken endocrine glands and gastrointestinal endocrine cells (GECs). SgIII was expressed in the pituitary, pineal, adrenal (medullary parts), parathyroid, and ultimobranchial glands, but not in the thyroid gland. It was also expressed in GECs of the stomach (proventriculus and gizzard), small and large intestines, and pancreatic islet cells. These SgIII-expressing cells co-expressed serotonin, somatostatin, gastric inhibitory polypeptide, glucagon-like peptide-1, glucagon, or insulin. These results suggest that SgIII is expressed in the endocrine cells that secrete peptide hormones, which mature via the intragranular enzymatic processing of prohormones and physiologically active amines in chickens.
Collapse
Affiliation(s)
- Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Satomi Morikawa
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Naoki Shinmura
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Hiroaki Moki
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Tadashi Yasui
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Azuma Tsukise
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Seiji Torii
- Laboratory of Secretion Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan (ST)
| | - Tsuyoshi Watanabe
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical College, Asahikawa, Japan (TW)
| | - Yoshinori Maeda
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan (YM, MH)
| | - Masahiro Hosaka
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan (YM, MH)
| |
Collapse
|
46
|
Faulkner LD, Dowling AR, Stuart RC, Nillni EA, Hill JW. Reduced melanocortin production causes sexual dysfunction in male mice with POMC neuronal insulin and leptin insensitivity. Endocrinology 2015; 156:1372-85. [PMID: 25590244 PMCID: PMC4399313 DOI: 10.1210/en.2014-1788] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Proopiomelanocortin (POMC)-derived peptides like α-melanocyte-stimulating hormone (MSH) substantially improve hepatic insulin sensitivity and regulate energy expenditure. Melanocortinergic agents are also powerful inducers of sexual arousal that are being investigated for a possible therapeutic role in erectile dysfunction. It is currently unclear whether reduced melanocortin (MC) activity may contribute to the sexual dysfunction accompanying obesity and type 2 diabetes. Male rodents with leptin and insulin resistance targeted to POMC neurons (leptin receptor [LepR]/insulin receptor [IR]POMC mice) exhibit obesity, hyperinsulinemia, hyperglycemia, and systemic insulin resistance. In this study, we demonstrate that LepR/IRPOMC males are also subfertile due to dramatic alterations in sexual behavior. Remarkably, these reproductive changes are accompanied by decreased α-MSH production not present when a single receptor type is deleted. Unexpectedly, behavioral sensitivity to α-MSH and MC receptor expression are also reduced in LepR/IRPOMC males, a potential adaptation of the MC system to altered α-MSH production. Together, these results suggest that concurrent insulin and leptin resistance in POMC neurons in individuals with obesity or type 2 diabetes can reduce endogenous α-MSH levels and impair sexual function.
Collapse
Affiliation(s)
- Latrice D Faulkner
- Department of Physiology and Pharmacology (L.D.F., A.R.D., J.W.H.), College of Medicine, The University of Toledo, Toledo, Ohio 43614-2598; and Division of Endocrinology (R.C.S., E.A.N.), Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, Rhode Island 02912-9107
| | | | | | | | | |
Collapse
|
47
|
Kim HJ, Hong J, Yoon HJ, Yoon YR, Kim SY. Carboxypeptidase E is a novel modulator of RANKL-induced osteoclast differentiation. Mol Cells 2014; 37:685-90. [PMID: 25220258 PMCID: PMC4179137 DOI: 10.14348/molcells.2014.0179] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 07/29/2014] [Accepted: 07/30/2014] [Indexed: 12/03/2022] Open
Abstract
Osteoclasts are large polykaryons that have the unique capacity to degrade bone and are generated by the differentiation of myeloid lineage progenitors. To identify the genes involved in osteoclast development, we performed microarray analysis, and we found that carboxypeptidase E (CPE), a prohormone processing enzyme, was highly upregulated in osteoclasts compared with their precursors, bone marrow-derived macrophages (BMMs). Here, we demonstrate a novel role for CPE in receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation. The overexpression of CPE in BMMs increases the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear osteoclasts and the expression of c-Fos and nuclear factor of activated T cells c1 (NFATc1), which are key regulators in osteoclastogenesis. Furthermore, employing CPE knockout mice, we show that CPE deficiency attenuates osteoclast formation. Together, our data suggest that CPE might be an important modulator of RANKL-induced osteoclast differentiation.
Collapse
Affiliation(s)
- Hyun-Ju Kim
- Department of Molecular Medicine, Cell and Matrix Research Institute, Clinical Trial Center, School of Medicine, Kyungpook National University, Daegu 700-422, Korea
- Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu 700-412, Korea
| | - JungMin Hong
- Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu 700-412, Korea
| | - Hye-Jin Yoon
- Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu 700-412, Korea
| | - Young-Ran Yoon
- Department of Molecular Medicine, Cell and Matrix Research Institute, Clinical Trial Center, School of Medicine, Kyungpook National University, Daegu 700-422, Korea
| | - Shin-Yoon Kim
- Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu 700-412, Korea
- Department of Orthopedic Surgery, School of Medicine, Kyungpook National University, Daegu 700-422, Korea
| |
Collapse
|
48
|
Fujita-Yoshigaki J, Matsuki-Fukushima M, Yokoyama M, Katsumata-Kato O. The sorting mechanism underlying the separation of salivary proteins into secretory granules in parotid glands. J Oral Biosci 2014. [DOI: 10.1016/j.job.2014.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
49
|
Bär F, Föh B, Pagel R, Schröder T, Schlichting H, Hirose M, Lemcke S, Klinger A, König P, Karsten CM, Büning J, Lehnert H, Fellermann K, Ibrahim SM, Sina C. Carboxypeptidase E modulates intestinal immune homeostasis and protects against experimental colitis in mice. PLoS One 2014; 9:e102347. [PMID: 25051500 PMCID: PMC4106776 DOI: 10.1371/journal.pone.0102347] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Accepted: 06/18/2014] [Indexed: 12/24/2022] Open
Abstract
Enteroendocrine cells (EEC) produce neuropeptides, which are crucially involved in the maintenance of the intestinal barrier. Hence, EEC dysfunction is suggested to be involved in the complex pathophysiology of inflammatory bowel disease (IBD), which is characterized by decreased intestinal barrier function. However, the underlying mechanisms for EEC dysfunction are not clear and suitable models for a better understanding are lacking. Here, we demonstrate that Carboxypeptidase E (CPE) is specifically expressed in EEC of the murine colon and ileum and that its deficiency is associated with reduced intestinal levels of Neuropeptide Y (NPY) and Peptide YY (PYY), which are both produced by EEC. Moreover, cpe−/− mice exhibit an aggravated course of DSS-induced chronic colitis compared to wildtype littermates. In addition, we observed elevated mucosal IL-6 and KC transcript levels already at baseline conditions in cpe−/− mice. Moreover, supernatants obtained from isolated intestinal crypts of cpe−/− mice lead to increased IL-6 and KC expression in MODE-K cells in the presence of LPS. This effect was reversible by co-administration of recombinant NPY, suggesting a CPE mediated immunosuppressive effect in the intestines by influencing the processing of specific neuropeptides. In this context, the chemotaxis of bone marrow derived macrophages towards respective supernatants was enhanced. In conclusion, our data point to an anti-inflammatory role of CPE in the intestine by influencing local cytokine levels and thus regulating the migration of myeloid immune cells into the mucosa. These findings highlight the importance of EEC for intestinal homeostasis and propose EEC as potential therapeutic targets in IBD.
Collapse
Affiliation(s)
- Florian Bär
- Medical Department I, University Hospital Schleswig-Holstein, Lübeck, Germany
- Institute of Anatomy, University of Lübeck, Lübeck, Germany
| | - Bandik Föh
- Medical Department I, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - René Pagel
- Medical Department I, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Torsten Schröder
- Medical Department I, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Heidi Schlichting
- Medical Department I, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Misa Hirose
- Department of Dermatology, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Susanne Lemcke
- Department of Dermatology, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Antje Klinger
- Institute of Anatomy, University of Lübeck, Lübeck, Germany
| | - Peter König
- Institute of Anatomy, University of Lübeck, Lübeck, Germany
| | - Christian M. Karsten
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Jürgen Büning
- Medical Department I, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Hendrik Lehnert
- Medical Department I, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Klaus Fellermann
- Medical Department I, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Saleh M. Ibrahim
- Department of Dermatology, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Christian Sina
- Medical Department I, University Hospital Schleswig-Holstein, Lübeck, Germany
- * E-mail:
| |
Collapse
|
50
|
Guizzetti L, McGirr R, Dhanvantari S. Two dipolar α-helices within hormone-encoding regions of proglucagon are sorting signals to the regulated secretory pathway. J Biol Chem 2014; 289:14968-80. [PMID: 24727476 DOI: 10.1074/jbc.m114.563684] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Proglucagon is expressed in pancreatic α cells, intestinal L cells, and some hypothalamic and brainstem neurons. Tissue-specific processing of proglucagon yields three major peptide hormones as follows: glucagon in the α cells and glucagon-like peptides (GLP)-1 and -2 in the L cells and neurons. Efficient sorting and packaging into the secretory granules of the regulated secretory pathway in each cell type are required for nutrient-regulated secretion of these proglucagon-derived peptides. Our previous work suggested that proglucagon is directed into granules by intrinsic sorting signals after initial processing to glicentin and major proglucagon fragment (McGirr, R., Guizzetti, L., and Dhanvantari, S. (2013) J. Endocrinol. 217, 229-240), leading to the hypothesis that sorting signals may be present in multiple domains. In the present study, we show that the α-helices within glucagon and GLP-1, but not GLP-2, act as sorting signals by efficiently directing a heterologous secretory protein to the regulated secretory pathway. Biophysical characterization of these peptides revealed that glucagon and GLP-1 each encode a nonamphipathic, dipolar α-helix, whereas the helix in GLP-2 is not dipolar. Surprisingly, glicentin and major proglucagon fragment were sorted with different efficiencies, thus providing evidence that proglucagon is first sorted to granules prior to processing. In contrast to many other prohormones in which sorting is directed by ordered prodomains, the sorting determinants of proglucagon lie within the ordered hormone domains of glucagon and GLP-1, illustrating that each prohormone has its own sorting "signature."
Collapse
Affiliation(s)
| | - Rebecca McGirr
- the Metabolism/Diabetes and Imaging Programs, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
| | - Savita Dhanvantari
- From the Departments of Medical Biophysics, the Metabolism/Diabetes and Imaging Programs, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada Pathology, and Medicine, University of Western Ontario, London, Ontario N6A 3K7 and
| |
Collapse
|