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Kimani CN, Reuter H, Kotzé SH, Muller CJF. Regeneration of Pancreatic Beta Cells by Modulation of Molecular Targets Using Plant-Derived Compounds: Pharmacological Mechanisms and Clinical Potential. Curr Issues Mol Biol 2023; 45:6216-6245. [PMID: 37623211 PMCID: PMC10453321 DOI: 10.3390/cimb45080392] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/20/2023] [Accepted: 07/22/2023] [Indexed: 08/26/2023] Open
Abstract
Type 2 diabetes (T2D) is characterized by pancreatic beta-cell dysfunction, increased cell death and loss of beta-cell mass despite chronic treatment. Consequently, there has been growing interest in developing beta cell-centered therapies. Beta-cell regeneration is mediated by augmented beta-cell proliferation, transdifferentiation of other islet cell types to functional beta-like cells or the reprograming of beta-cell progenitors into fully differentiated beta cells. This mediation is orchestrated by beta-cell differentiation transcription factors and the regulation of the cell cycle machinery. This review investigates the beta-cell regenerative potential of antidiabetic plant extracts and phytochemicals. Various preclinical studies, including in vitro, in vivo and ex vivo studies, are highlighted. Further, the potential regenerative mechanisms and the intra and extracellular mediators that are of significance are discussed. Also, the potential of phytochemicals to translate into regenerative therapies for T2D patients is highlighted, and some suggestions regarding future perspectives are made.
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Affiliation(s)
- Clare Njoki Kimani
- Biomedical Research and Innovation Platform (BRIP), South African Medical Research Council (SAMRC), Cape Town 7505, South Africa;
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town 7505, South Africa
| | - Helmuth Reuter
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town 7505, South Africa
| | - Sanet Henriët Kotzé
- Division of Clinical Anatomy, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town 7505, South Africa
- Division of Anatomy, Department of Biomedical Sciences, School of Veterinary Medicine, Ross University, Basseterre P.O. Box 334, Saint Kitts and Nevis
| | - Christo John Fredrick Muller
- Biomedical Research and Innovation Platform (BRIP), South African Medical Research Council (SAMRC), Cape Town 7505, South Africa;
- Centre for Cardio-Metabolic Research in Africa, Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch 7600, South Africa
- Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa
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Lee D, Son SR, Qi Y, Kang KS, Jang DS. (1' S)-1'-Acetoxyeugenol Acetate Enhances Glucose-Stimulated Insulin Secretion. PLANTS (BASEL, SWITZERLAND) 2023; 12:579. [PMID: 36771665 PMCID: PMC9919771 DOI: 10.3390/plants12030579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/25/2023] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Alpinia galanga have been widely used as spice or traditional medicine in East Asia, commonly known as Thai ginger. In the present study, seven major phenylpropanoids, (±)-1'-hydoxychavicol acetate (1; HCA), (1'S)-1'-acetoxychavicol acetate (2; ACA), (1'S)-1'-acetoxyeugenol acetate (3; AEA), eugenyl acetate (4), trans-p-coumaraldehyde (5), trans-p-acetoxycinnamyl alcohol (6), and trans-p-coumaryl diacetate (7), were isolated from the 95% EtOH and hot water extracts of the rhizomes of A. galanga by chromatographic method. Phenylpropanoids 1-7 were evaluated for glucose-stimulated insulin secretion (GSIS) effect and α-glucosidase inhibitory activity. Phenylpropanoids 1-4 increase GSIS effect without cytotoxicity in rat INS-1 pancreatic β-cells. In addition, INS-1 cells were treated with AEA (3) to determine a plausible mechanism of β-cell function and insulin secretion through determining the activation of insulin receptor substrate-2 (IRS-2), phosphatidylinositol 3-kinase (PI3K), Akt, and pancreatic and duodenal homeobox-1 (PDX-1). Upon treatment with AEA (3), INS-1 cells showed an increase in these protein expressions. Meanwhile, AEA (3) exhibited α-glucosidase inhibitory activity. On the basis of the above findings, we suggest AEA (3) as a potential antidiabetic agent.
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Affiliation(s)
- Dahae Lee
- College of Korean Medicine, Gachon University, Seongnam 13120, Republic of Korea
| | - So-Ri Son
- Department of Biomedical and Pharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Yutong Qi
- Department of Life and Nanopharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Ki Sung Kang
- College of Korean Medicine, Gachon University, Seongnam 13120, Republic of Korea
| | - Dae Sik Jang
- Department of Biomedical and Pharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
- Department of Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 02447, Republic of Korea
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Yan H, Chen Z, Zhang H, Yang W, Liu X, Meng Y, Xiang R, Wu Z, Ye J, Chi Y, Yang J. Intracellular ATP Signaling Contributes to FAM3A-Induced PDX1 Upregulation in Pancreatic Beta Cells. Exp Clin Endocrinol Diabetes 2021; 130:498-508. [PMID: 34592773 PMCID: PMC9377833 DOI: 10.1055/a-1608-0607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
FAM3A is a recently identified mitochondrial protein that stimulates
pancreatic-duodenal homeobox 1 (PDX1) and insulin expressions by promoting ATP
release in islet β cells. In this study, the role of intracellular ATP
in FAM3A-induced PDX1 expression in pancreatic β cells was further
examined. Acute FAM3A inhibition using siRNA transfection in mouse pancreatic
islets significantly reduced PDX1 expression, impaired insulin secretion, and
caused glucose intolerance in normal mice.
In vitro
, FAM3A overexpression
elevated both intracellular and extracellular ATP contents and promoted PDX1
expression and insulin secretion. FAM3A-induced increase in cellular calcium
(Ca
2+
) levels, PDX1 expression, and insulin secretion,
while these were significantly repressed by inhibitors of P2 receptors or the
L-type Ca
2+
channels. FAM3A-induced PDX1 expression was
abolished by a calmodulin inhibitor. Likewise, FAM3A-induced β-cell
proliferation was also inhibited by a P2 receptor inhibitor and an L-type
Ca
2+
channels inhibitor. Both intracellular and
extracellular ATP contributed to FAM3A-induced PDX1 expression, insulin
secretion, and proliferation of pancreatic β cells.
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Affiliation(s)
- Han Yan
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science of the Ministry of Education, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing 100191, China
| | - Zhenzhen Chen
- Hypertension Center, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Beijing 100037, China
| | - Haizeng Zhang
- Hypertension Center, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Beijing 100037, China
| | - Weili Yang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science of the Ministry of Education, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing 100191, China.,Beijing Key Laboratory of Diabetes Research and Care, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
| | - Xiangyang Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science of the Ministry of Education, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing 100191, China
| | - Yuhong Meng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science of the Ministry of Education, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing 100191, China
| | - Rui Xiang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science of the Ministry of Education, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing 100191, China
| | - Zhe Wu
- Department of Gastroenterology, Peking University People's Hospital, Beijing 100044, China
| | - Jingjing Ye
- Department of Gastroenterology, Peking University People's Hospital, Beijing 100044, China
| | - Yujing Chi
- Department of Central Laboratory & Institute of Clinical Molecular Biology, Peking University People's Hospital, Beijing 100044, China
| | - Jichun Yang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science of the Ministry of Education, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing 100191, China
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Ghasemi A, Afzali H, Jeddi S. Effect of oral nitrite administration on gene expression of SNARE proteins involved in insulin secretion from pancreatic islets of male type 2 diabetic rats. Biomed J 2021; 45:387-395. [PMID: 34326021 PMCID: PMC9250122 DOI: 10.1016/j.bj.2021.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/30/2021] [Accepted: 04/15/2021] [Indexed: 02/06/2023] Open
Abstract
Background Nitrite stimulates insulin secretion from pancreatic β-cells; however, the underlying mechanisms have not been completely addressed. The aim of this study is to determine effect of nitrite on gene expression of SNARE proteins involved in insulin secretion from isolated pancreatic islets in Type 2 diabetic Wistar rats. Methods Three groups of rats were studied (n = 10/group): Control, diabetes, and diabetes + nitrite, which treated with sodium nitrite (50 mg/L) for 8 weeks. Type 2 diabetes was induced using a low-dose of streptozotocin (25 mg/kg) combined with high-fat diet. At the end of the study, pancreatic islets were isolated and mRNA expressions of interested genes were measured; in addition, protein expression of proinsulin and C-peptide in pancreatic tissue was assessed using immunofluorescence staining. Results Compared with controls, in the isolated pancreatic islets of Type 2 diabetic rats, mRNA expression of glucokinase (59%), syntaxin1A (49%), SNAP25 (70%), Munc18b (48%), insulin1 (56%), and insulin2 (52%) as well as protein expression of proinsulin and C-peptide were lower. In diabetic rats, nitrite administration significantly increased gene expression of glucokinase, synaptotagmin III, syntaxin1A, SNAP25, Munc18b, and insulin genes as well as increased protein expression of proinsulin and C-peptide. Conclusion Stimulatory effect of nitrite on insulin secretion in Type 2 diabetic rats is at least in part due to increased gene expression of molecules involved in glucose sensing (glucokinase), calcium sensing (synaptotagmin III), and exocytosis of insulin vesicles (syntaxin1A, SNAP25, and Munc18b) as well as increased expression of insulin genes.
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Affiliation(s)
- Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamideh Afzali
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sajad Jeddi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Khatri R, Mazurek S, Petry SF, Linn T. Mesenchymal stem cells promote pancreatic β-cell regeneration through downregulation of FoxO1 pathway. Stem Cell Res Ther 2020; 11:497. [PMID: 33239104 PMCID: PMC7687794 DOI: 10.1186/s13287-020-02007-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 11/02/2020] [Indexed: 12/22/2022] Open
Abstract
Background Mesenchymal stem cells (MSC) are non-haematopoietic, fibroblast-like multipotent stromal cells. In the injured pancreas, these cells are assumed to secrete growth factors and immunomodulatory molecules, which facilitate the regeneration of pre-existing β-cells. However, when MSC are delivered intravenously, their majority is entrapped in the lungs and does not reach the pancreas. Therefore, the aim of this investigation was to compare the regenerative support of hTERT-MSC (human telomerase reverse transcriptase mesenchymal stem cells) via intrapancreatic (IPR) and intravenous route (IVR). Methods hTERT-MSC were administered by IPR and IVR to 50% pancreatectomized NMRI nude mice. After eight days, blood glucose level, body weight, and residual pancreatic weight were measured. Proliferating pancreatic β-cells were labelled and identified with bromodeoxyuridine (BrdU) in vivo. The number of residual islets and the frequency of proliferating β-cells were compared in different groups with sequential pancreatic sections. The pancreatic insulin content was evaluated by enzyme-linked immunosorbent assay (ELISA) and the presence of hTERT-MSC with human Alu sequence. Murine gene expression of growth factors, β-cell specific molecules and proinflammatory cytokines were inspected by real-time polymerase chain reaction (RT-PCR) and Western blot. Results This study evaluated the regenerative potential of the murine pancreas post-hTERT-MSC administration through the intrapancreatic (IPR) and intravenous route (IVR). Both routes of hTERT-MSC transplantation (IVR and IPR) increased the incorporation of BrdU by pancreatic β-cells compared to control. MSC induced epidermal growth factor (EGF) expression and inhibited proinflammatory cytokines (IFN-γ and TNF-α). FOXA2 and PDX-1 characteristics for pancreatic progenitor cells were activated via AKT/ PDX-1/ FoxO1 signalling pathway. Conclusion The infusion of hTERT-MSC after partial pancreatectomy (Px) through the IVR and IPR facilitated the proliferation of autochthonous pancreatic β-cells and provided evidence for a regenerative influence of MSC on the endocrine pancreas. Moderate benefit of IPR over IVR was observed which could be a new treatment option for preventing diabetes mellitus after pancreas surgery. Supplementary information The online version contains supplementary material available at at 10.1186/s13287-020-02007-9.
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Affiliation(s)
- Rahul Khatri
- Third Medical Department, Clinical Research Lab, Justus Liebig University Giessen, Giessen, Germany
| | - Sybille Mazurek
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | | | - Thomas Linn
- Third Medical Department, Clinical Research Lab, Justus Liebig University Giessen, Giessen, Germany. .,Clinical Research Unit, Centre of Internal Medicine, Friedrichstrasse. 20/ Aulweg 123, 35392, Giessen, Germany.
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Špiranec Spes K, Hupp S, Werner F, Koch F, Völker K, Krebes L, Kämmerer U, Heinze KG, Braunger BM, Kuhn M. Natriuretic Peptides Attenuate Retinal Pathological Neovascularization Via Cyclic Guanosine Monophosphate Signaling in Pericytes and Astrocytes. Arterioscler Thromb Vasc Biol 2019; 40:159-174. [PMID: 31619060 DOI: 10.1161/atvbaha.119.313400] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE In proliferative retinopathies, complications derived from neovascularization cause blindness. During early disease, pericyte's apoptosis contributes to endothelial dysfunction and leakage. Hypoxia then drives VEGF (vascular endothelial growth factor) secretion and pathological neoangiogenesis. Cardiac ANP (atrial natriuretic peptide) contributes to systemic microcirculatory homeostasis. ANP is also formed in the retina, with unclear functions. Here, we characterized whether endogenously formed ANP regulates retinal (neo)angiogenesis. Approach and Results: Retinal vascular development and ischemia-driven neovascularization were studied in mice with global deletion of GC-A (guanylyl cyclase-A), the cGMP (cyclic guanosine monophosphate)-forming ANP receptor. Mice with a floxed GC-A gene were interbred with Tie2-Cre, GFAP-Cre, or PDGF-Rβ-CreERT2 lines to dissect the endothelial, astrocyte versus pericyte-mediated actions of ANP in vivo. In neonates with global GC-A deletion (KO), vascular development was mildly delayed. Moreover, such KO mice showed augmented vascular regression and exacerbated ischemia-driven neovascularization in the model of oxygen-induced retinopathy. Notably, absence of GC-A in endothelial cells did not impact retinal vascular development or pathological neovascularization. In vitro ANP/GC-A/cGMP signaling, via activation of cGMP-dependent protein kinase I, inhibited hypoxia-driven astrocyte's VEGF secretion and TGF-β (transforming growth factor beta)-induced pericyte apoptosis. In neonates lacking ANP/GC-A signaling in astrocytes, vascular development and hyperoxia-driven vascular regression were unaltered; ischemia-induced neovascularization was modestly increased. Remarkably, inactivation of GC-A in pericytes retarded physiological retinal vascularization and markedly enhanced cell apoptosis, vascular regression, and subsequent neovascularization in oxygen-induced retinopathy. CONCLUSIONS Protective pericyte effects of the ANP/GC-A/cGMP pathway counterregulate the initiation and progression of experimental proliferative retinopathy. Our observations indicate augmentation of endogenous pericyte ANP signaling as target for treatment of retinopathies associated with neovascularization.
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Affiliation(s)
- Katarina Špiranec Spes
- From the Institute of Physiology, University of Würzburg (K.Š.S, S.H., F.W., F.K., K.V., L.K., M.K.).,Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K.Š.S., M.K.)
| | - Sabrina Hupp
- From the Institute of Physiology, University of Würzburg (K.Š.S, S.H., F.W., F.K., K.V., L.K., M.K.)
| | - Franziska Werner
- From the Institute of Physiology, University of Würzburg (K.Š.S, S.H., F.W., F.K., K.V., L.K., M.K.)
| | - Franziska Koch
- From the Institute of Physiology, University of Würzburg (K.Š.S, S.H., F.W., F.K., K.V., L.K., M.K.)
| | - Katharina Völker
- From the Institute of Physiology, University of Würzburg (K.Š.S, S.H., F.W., F.K., K.V., L.K., M.K.)
| | - Lisa Krebes
- From the Institute of Physiology, University of Würzburg (K.Š.S, S.H., F.W., F.K., K.V., L.K., M.K.)
| | - Ulrike Kämmerer
- Department for Gynecology and Obstetrics, University Hospital Würzburg, Germany (U.K.)
| | - Katrin G Heinze
- Rudolf-Virchow Center for Experimental Biomedicine, University of Würzburg, Germany (K.G.H)
| | - Barbara M Braunger
- Institute of Anatomy and Cell Biology, Julius-Maximilians-University of Würzburg, Germany (B.M.B)
| | - Michaela Kuhn
- From the Institute of Physiology, University of Würzburg (K.Š.S, S.H., F.W., F.K., K.V., L.K., M.K.).,Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K.Š.S., M.K.)
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Shapiro MR, Atkinson MA, Brusko TM. Pleiotropic roles of the insulin-like growth factor axis in type 1 diabetes. Curr Opin Endocrinol Diabetes Obes 2019; 26:188-194. [PMID: 31145130 PMCID: PMC7135378 DOI: 10.1097/med.0000000000000484] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE OF REVIEW We review studies demonstrating lowered levels of insulin-like growth factors (IGFs) in patients with recent-onset type 1 diabetes (T1D) and discuss their potential roles in the disorder's pathogenesis. RECENT FINDINGS IGFs have long been recognized as a class of hormones that promote growth, development, and cellular metabolism throughout the human body. More recently, studies have noted an association between reduced pancreatic weight/volume and T1D. Thus, we believe it is important to understand pancreatic regulation of IGF expression and bioavailability, as well as the impact of IGFs on pancreatic growth and islet health. Additional studies of IGFs have been extended to their influence on the inflammatory/regulatory balance of monocytes, B cells, and T cells; features which have been previously established to show dysregulation in settings of T1D. SUMMARY These data suggest that IGFs may prevent known impairments in the pancreas and immune system in T1D and underscore the need to extend these studies, some of which were performed in health or other autoimmune diseases, toward T1D specifically. Collectively, the work emphasized here support the potential therapeutic use of IGFs in T1D prevention efforts as pancreatic growth factors and/or immunoregulatory agents.
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Affiliation(s)
- Melanie R. Shapiro
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, Florida, USA
| | - Mark A. Atkinson
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, Florida, USA
- Department of Pediatrics, The University of Florida Diabetes Institute, Gainesville, Florida, USA
| | - Todd M. Brusko
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, Florida, USA
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DiNicolantonio JJ, McCarty M. Autophagy-induced degradation of Notch1, achieved through intermittent fasting, may promote beta cell neogenesis: implications for reversal of type 2 diabetes. Open Heart 2019; 6:e001028. [PMID: 31218007 PMCID: PMC6546199 DOI: 10.1136/openhrt-2019-001028] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/06/2019] [Indexed: 02/06/2023] Open
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Tan H, Wu C, Jin L. A Possible Role for Long Interspersed Nuclear Elements-1 (LINE-1) in Huntington's Disease Progression. Med Sci Monit 2018; 24:3644-3652. [PMID: 29851926 PMCID: PMC6007493 DOI: 10.12659/msm.907328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/04/2018] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Recent studies have shown that increased mobilization of Long Interspersed Nuclear Elements-1 (L1) can promote the pathophysiology of multiple neurological diseases. However, its role in Huntington's disease (HD) remains unknown. MATERIAL AND METHODS R6/2 mice - a common mouse model of HD - were used to evaluate changes in L1 mobilization. Pyrosequencing was used to evaluate methylation content changes. L1-ORF1 and L1-ORF2 expression analysis were evaluated by RT-PCR and immunoblotting. Changes in pro-survival signaling were evaluated by L1-ORF overexpression studies and validated in the mouse model by immunohistochemistry and immunoblotting. RESULTS We found an increased mobilization of L1 elements in the caudate genome of R6/2 mice (p<0.05) - a common mouse model of HD - but not in wild-type mice. Subsequent pyrosequencing and expression analysis showed that the L1 elements were hypomethylated and their respective ORFs were overexpressed in the affected tissues. In addition, a significant decrease in the pro-survival proteins such as the phosphoproteins of AKT target proteins, mTORC1 activity, and AMPK alpha levels was observed with the increase in the expression L1-ORF2. CONCLUSIONS These findings indicate that hyperactive retrotransposition of L1 triggers a downstream signaling pathway affecting the neuronal survival pathways via downregulation of mTORC1 activity and AMPKalpha and increasing apoptosis in neurons.
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Affiliation(s)
- Huiping Tan
- Reproductive Medicine Center, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Chunlin Wu
- Reproductive Medicine Center, Wuhan No. 1 Hospital, Wuhan, Hubei, P.R. China
| | - Lei Jin
- Reproductive Medicine Center, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
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