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Zhao L, Hu H, Zhang L, Liu Z, Huang Y, Liu Q, Jin L, Zhu M, Zhang L. Inflammation in diabetes complications: molecular mechanisms and therapeutic interventions. MedComm (Beijing) 2024; 5:e516. [PMID: 38617433 PMCID: PMC11014467 DOI: 10.1002/mco2.516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 02/16/2024] [Accepted: 02/21/2024] [Indexed: 04/16/2024] Open
Abstract
At present, diabetes mellitus (DM) has been one of the most endangering healthy diseases. Current therapies contain controlling high blood sugar, reducing risk factors like obesity, hypertension, and so on; however, DM patients inevitably and eventually progress into different types of diabetes complications, resulting in poor quality of life. Unfortunately, the clear etiology and pathogenesis of diabetes complications have not been elucidated owing to intricate whole-body systems. The immune system was responsible to regulate homeostasis by triggering or resolving inflammatory response, indicating it may be necessary to diabetes complications. In fact, previous studies have been shown inflammation plays multifunctional roles in the pathogenesis of diabetes complications and is attracting attention to be the meaningful therapeutic strategy. To this end, this review systematically concluded the current studies over the relationships of susceptible diabetes complications (e.g., diabetic cardiomyopathy, diabetic retinopathy, diabetic peripheral neuropathy, and diabetic nephropathy) and inflammation, ranging from immune cell response, cytokines interaction to pathomechanism of organ injury. Besides, we also summarized various therapeutic strategies to improve diabetes complications by target inflammation from special remedies to conventional lifestyle changes. This review will offer a panoramic insight into the mechanisms of diabetes complications from an inflammatory perspective and also discuss contemporary clinical interventions.
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Affiliation(s)
- Lu Zhao
- Department of Biology and MedicineCollege of Life Science, Zhejiang Chinese Medical UniversityHangzhouChina
| | - Haoran Hu
- Department of Biology and MedicineCollege of Life Science, Zhejiang Chinese Medical UniversityHangzhouChina
| | - Lin Zhang
- Department of Biology and MedicineCollege of Life Science, Zhejiang Chinese Medical UniversityHangzhouChina
| | - Zheting Liu
- Department of Biology and MedicineCollege of Life Science, Zhejiang Chinese Medical UniversityHangzhouChina
| | - Yunchao Huang
- Department of Biology and MedicineCollege of Life Science, Zhejiang Chinese Medical UniversityHangzhouChina
| | - Qian Liu
- National Demonstration Center for Experimental Traditional Chinese Medicines Education (Zhejiang Chinese Medical University)College of Pharmaceutical Science, Zhejiang Chinese Medical UniversityHangzhouChina
| | - Liang Jin
- Department of Biology and MedicineCollege of Life Science, Zhejiang Chinese Medical UniversityHangzhouChina
- Shanghai Key Laboratory of Compound Chinese Medicines, The Ministry of Education Key Laboratory for Standardization of Chinese Medicines, Institute of Chinese Materia MedicaShanghai University of Traditional Chinese MedicineShanghaiChina
| | - Meifei Zhu
- Department of Critical Care MedicineThe First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine)HangzhouChina
| | - Ling Zhang
- Department of Biology and MedicineCollege of Life Science, Zhejiang Chinese Medical UniversityHangzhouChina
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Lee D, Yoon E, Ham SJ, Lee K, Jang H, Woo D, Lee DH, Kim S, Choi S, Chung J. Diabetic sensory neuropathy and insulin resistance are induced by loss of UCHL1 in Drosophila. Nat Commun 2024; 15:468. [PMID: 38212312 PMCID: PMC10784524 DOI: 10.1038/s41467-024-44747-9] [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: 01/01/2023] [Accepted: 12/29/2023] [Indexed: 01/13/2024] Open
Abstract
Diabetic sensory neuropathy (DSN) is one of the most common complications of type 2 diabetes (T2D), however the molecular mechanistic association between T2D and DSN remains elusive. Here we identify ubiquitin C-terminal hydrolase L1 (UCHL1), a deubiquitinase highly expressed in neurons, as a key molecule underlying T2D and DSN. Genetic ablation of UCHL1 leads to neuronal insulin resistance and T2D-related symptoms in Drosophila. Furthermore, loss of UCHL1 induces DSN-like phenotypes, including numbness to external noxious stimuli and axonal degeneration of sensory neurons in flies' legs. Conversely, UCHL1 overexpression improves DSN-like defects of T2D model flies. UCHL1 governs insulin signaling by deubiquitinating insulin receptor substrate 1 (IRS1) and antagonizes an E3 ligase of IRS1, Cullin 1 (CUL1). Consistent with these results, genetic and pharmacological suppression of CUL1 activity rescues T2D- and DSN-associated phenotypes. Therefore, our findings suggest a complete set of genetic factors explaining T2D and DSN, together with potential remedies for the diseases.
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Affiliation(s)
- Daewon Lee
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, Republic of Korea
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Eunju Yoon
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, Republic of Korea
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Su Jin Ham
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, Republic of Korea
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Kunwoo Lee
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Hansaem Jang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Daihn Woo
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, Republic of Korea
| | - Da Hyun Lee
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, Republic of Korea
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sehyeon Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, Republic of Korea
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sekyu Choi
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
| | - Jongkyeong Chung
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, Republic of Korea.
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
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3
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Zhu J, Hu Z, Luo Y, Liu Y, Luo W, Du X, Luo Z, Hu J, Peng S. Diabetic peripheral neuropathy: pathogenetic mechanisms and treatment. Front Endocrinol (Lausanne) 2024; 14:1265372. [PMID: 38264279 PMCID: PMC10803883 DOI: 10.3389/fendo.2023.1265372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 12/14/2023] [Indexed: 01/25/2024] Open
Abstract
Diabetic peripheral neuropathy (DPN) refers to the development of peripheral nerve dysfunction in patients with diabetes when other causes are excluded. Diabetic distal symmetric polyneuropathy (DSPN) is the most representative form of DPN. As one of the most common complications of diabetes, its prevalence increases with the duration of diabetes. 10-15% of newly diagnosed T2DM patients have DSPN, and the prevalence can exceed 50% in patients with diabetes for more than 10 years. Bilateral limb pain, numbness, and paresthesia are the most common clinical manifestations in patients with DPN, and in severe cases, foot ulcers can occur, even leading to amputation. The etiology and pathogenesis of diabetic neuropathy are not yet completely clarified, but hyperglycemia, disorders of lipid metabolism, and abnormalities in insulin signaling pathways are currently considered to be the initiating factors for a range of pathophysiological changes in DPN. In the presence of abnormal metabolic factors, the normal structure and function of the entire peripheral nervous system are disrupted, including myelinated and unmyelinated nerve axons, perikaryon, neurovascular, and glial cells. In addition, abnormalities in the insulin signaling pathway will inhibit neural axon repair and promote apoptosis of damaged cells. Here, we will discuss recent advances in the study of DPN mechanisms, including oxidative stress pathways, mechanisms of microvascular damage, mechanisms of damage to insulin receptor signaling pathways, and other potential mechanisms associated with neuroinflammation, mitochondrial dysfunction, and cellular oxidative damage. Identifying the contributions from each pathway to neuropathy and the associations between them may help us to further explore more targeted screening and treatment interventions.
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Affiliation(s)
- Jinxi Zhu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
- The Second Clinical Medical College of Nanchang University, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Ziyan Hu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
- The Second Clinical Medical College of Nanchang University, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yifan Luo
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yinuo Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Wei Luo
- Department of Sports Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaohong Du
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Zhenzhong Luo
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Jialing Hu
- Department of Emergency Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Shengliang Peng
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
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Chen T, Dalton G, Oh SH, Maeso-Diaz R, Du K, Meyers RA, Guy C, Abdelmalek MF, Henao R, Guarnieri P, Pullen SS, Gregory S, Locker J, Brown JM, Diehl AM. Hepatocyte Smoothened Activity Controls Susceptibility to Insulin Resistance and Nonalcoholic Fatty Liver Disease. Cell Mol Gastroenterol Hepatol 2022; 15:949-970. [PMID: 36535507 PMCID: PMC9957752 DOI: 10.1016/j.jcmgh.2022.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 12/09/2022] [Accepted: 12/09/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND & AIMS Nonalcoholic steatohepatitis (NASH), a leading cause of cirrhosis, strongly associates with the metabolic syndrome, an insulin-resistant proinflammatory state that disrupts energy balance and promotes progressive liver degeneration. We aimed to define the role of Smoothened (Smo), an obligatory component of the Hedgehog signaling pathway, in controlling hepatocyte metabolic homeostasis and, thereby, susceptibility to NASH. METHODS We conditionally deleted Smo in hepatocytes of healthy chow-fed mice and performed metabolic phenotyping, coupled with single-cell RNA sequencing (RNA-seq), to characterize the role of hepatocyte Smo in regulating basal hepatic and systemic metabolic homeostasis. Liver RNA-seq datasets from 2 large human cohorts were also analyzed to define the relationship between Smo and NASH susceptibility in people. RESULTS Hepatocyte Smo deletion inhibited the Hedgehog pathway and promoted fatty liver, hyperinsulinemia, and insulin resistance. We identified a plausible mechanism whereby inactivation of Smo stimulated the mTORC1-SREBP1c signaling axis, which promoted lipogenesis while inhibiting the hepatic insulin cascade. Transcriptomics of bulk and single Smo-deficient hepatocytes supported suppression of insulin signaling and also revealed molecular abnormalities associated with oxidative stress and mitochondrial dysfunction. Analysis of human bulk RNA-seq data revealed that Smo expression was (1) highest in healthy livers, (2) lower in livers with NASH than in those with simple steatosis, (3) negatively correlated with markers of insulin resistance and liver injury, and (4) declined progressively as fibrosis severity worsened. CONCLUSIONS The Hedgehog pathway controls insulin sensitivity and energy homeostasis in adult livers. Loss of hepatocyte Hedgehog activity induces hepatic and systemic metabolic stress and enhances susceptibility to NASH by promoting hepatic lipoxicity and insulin resistance.
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Affiliation(s)
- Tianyi Chen
- Department of Medicine, Duke University, Durham, North Carolina
| | - George Dalton
- Department of Medicine, Duke University, Durham, North Carolina
| | - Seh-Hoon Oh
- Department of Medicine, Duke University, Durham, North Carolina
| | | | - Kuo Du
- Department of Medicine, Duke University, Durham, North Carolina
| | - Rachel A Meyers
- Department of Medicine, Duke University, Durham, North Carolina
| | - Cynthia Guy
- Department of Medicine, Duke University, Durham, North Carolina
| | | | - Ricardo Henao
- Department of Medicine, Duke University, Durham, North Carolina
| | - Paolo Guarnieri
- Boehringer Ingelheim Pharmaceuticals Inc, Ridgefield, Connecticut
| | - Steven S Pullen
- Boehringer Ingelheim Pharmaceuticals Inc, Ridgefield, Connecticut
| | - Simon Gregory
- Department of Medicine, Duke University, Durham, North Carolina
| | - Joseph Locker
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - J Mark Brown
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio
| | - Anna Mae Diehl
- Department of Medicine, Duke University, Durham, North Carolina.
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Osonoi S, Mizukami H, Takeuchi Y, Sugawa H, Ogasawara S, Takaku S, Sasaki T, Kudoh K, Ito K, Sango K, Nagai R, Yamamoto Y, Daimon M, Yamamoto H, Yagihashi S. RAGE activation in macrophages and development of experimental diabetic polyneuropathy. JCI Insight 2022; 7:160555. [PMID: 36477360 PMCID: PMC9746912 DOI: 10.1172/jci.insight.160555] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 10/19/2022] [Indexed: 12/12/2022] Open
Abstract
It is suggested that activation of receptor for advanced glycation end products (RAGE) induces proinflammatory response in diabetic nerve tissues. Macrophage infiltration is invoked in the pathogenesis of diabetic polyneuropathy (DPN), while the association between macrophage and RAGE activation and the downstream effects of macrophages remain to be fully clarified in DPN. This study explored the role of RAGE in the pathogenesis of DPN through the modified macrophages. Infiltrating proinflammatory macrophages impaired insulin sensitivity, atrophied the neurons in dorsal root ganglion, and slowed retrograde axonal transport (RAT) in the sciatic nerve of type 1 diabetic mice. RAGE-null mice showed an increase in the population of antiinflammatory macrophages, accompanied by intact insulin sensitivity, normalized ganglion cells, and RAT. BM transplantation from RAGE-null mice to diabetic mice protected the peripheral nerve deficits, suggesting that RAGE is a major determinant for the polarity of macrophages in DPN. In vitro coculture analyses revealed proinflammatory macrophage-elicited insulin resistance in the primary neuronal cells isolated from dorsal root ganglia. Applying time-lapse recording disclosed a direct impact of proinflammatory macrophage and insulin resistance on the RAT deficits in primary neuronal cultures. These results provide a potentially novel insight into the development of RAGE-related DPN.
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Affiliation(s)
- Sho Osonoi
- Department of Pathology and Molecular Medicine and,Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | | | - Yuki Takeuchi
- Department of Pathology and Molecular Medicine and,Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Hikari Sugawa
- Laboratory of Food and Regulation Biology, Department of Bioscience, School of Agriculture, Tokai University, Higashi-ku, Kumamoto, Japan
| | | | - Shizuka Takaku
- Diabetic Neuropathy Project, Department of Diseases and Infection, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | | | | | - Koichi Ito
- Department of Bioscience and Laboratory Medicine, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan
| | - Kazunori Sango
- Diabetic Neuropathy Project, Department of Diseases and Infection, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Ryoji Nagai
- Laboratory of Food and Regulation Biology, Department of Bioscience, School of Agriculture, Tokai University, Higashi-ku, Kumamoto, Japan
| | - Yasuhiko Yamamoto
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Makoto Daimon
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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Insulin and Its Key Role for Mitochondrial Function/Dysfunction and Quality Control: A Shared Link between Dysmetabolism and Neurodegeneration. BIOLOGY 2022; 11:biology11060943. [PMID: 35741464 PMCID: PMC9220302 DOI: 10.3390/biology11060943] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/01/2022] [Accepted: 06/17/2022] [Indexed: 02/07/2023]
Abstract
Insulin was discovered and isolated from the beta cells of pancreatic islets of dogs and is associated with the regulation of peripheral glucose homeostasis. Insulin produced in the brain is related to synaptic plasticity and memory. Defective insulin signaling plays a role in brain dysfunction, such as neurodegenerative disease. Growing evidence suggests a link between metabolic disorders, such as diabetes and obesity, and neurodegenerative diseases, especially Alzheimer's disease (AD). This association is due to a common state of insulin resistance (IR) and mitochondrial dysfunction. This review takes a journey into the past to summarize what was known about the physiological and pathological role of insulin in peripheral tissues and the brain. Then, it will land in the present to analyze the insulin role on mitochondrial health and the effects on insulin resistance and neurodegenerative diseases that are IR-dependent. Specifically, we will focus our attention on the quality control of mitochondria (MQC), such as mitochondrial dynamics, mitochondrial biogenesis, and selective autophagy (mitophagy), in healthy and altered cases. Finally, this review will be projected toward the future by examining the most promising treatments that target the mitochondria to cure neurodegenerative diseases associated with metabolic disorders.
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7
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An Z, Zheng D, Wei D, Jiang D, Xing X, Liu C. Correlation between Acylcarnitine and Peripheral Neuropathy in Type 2 Diabetes Mellitus. J Diabetes Res 2022; 2022:8115173. [PMID: 35224109 PMCID: PMC8872664 DOI: 10.1155/2022/8115173] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/14/2022] [Accepted: 02/08/2022] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE In patients with type 2 diabetes mellitus (T2DM), it is unknown whether acylcarnitine changes in the patient's plasma as diabetic peripheral neuropathy (DPN) occurs. The purpose of the present study was to investigate the correlation between acylcarnitines and DPN in Chinese patients with T2DM. METHODS A total of 508 patients admitted to the First Affiliated Hospital of Jinzhou Medical University were included in this study, and all of whom were hospitalized for T2DM from January 2018 to December 2020. The diagnostic criteria for DPN were based on the 2017 Chinese Guidelines for the Prevention of Type 2 Diabetes. The contents of 25 acylcarnitine metabolites in fasting blood were determined by mass spectrometry. The measured acylcarnitines were classified by factor analysis, and the factors were extracted. To determine the correlation between acylcarnitines and DPN, binary logistic regression analysis was applied. RESULTS Among the 508 T2DM patients, 270 had DPN. Six factors were extracted from 25 acylcarnitines, and the cumulative contribution rate of variance was 61.02%. After the adjustment for other potential confounding factors, such as other carnitines and conventional risk factors, Factor 2 was positively associated with an increased risk of DPN (OR: 1.38, 95% CI: 1.13-1.69). Factor 2 contained acetylcarnitine (C2), propionylcarnitine (C3), butylcarnitine (C4), and isovalerylcarnitine (C5). CONCLUSIONS Plasma levels of short-chain acylcarnitines (C2, C3, C4, and C5) were positively associated with DPN risk.
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Affiliation(s)
- Zhenni An
- Department of Endocrinology, First Affiliated Hospital of Jinzhou Medical University, 121001, China
| | - Danmeng Zheng
- Department of Endocrinology, First Affiliated Hospital of Jinzhou Medical University, 121001, China
| | - Dongzhuo Wei
- Department of Clinical Discipline of Chinese and Western Integrative Medicine, Liaoning University of Traditional Chinese Medicine, 110847, China
| | - Dingwen Jiang
- Department of Endocrinology, First Affiliated Hospital of Jinzhou Medical University, 121001, China
| | - Xuejiao Xing
- Department of Endocrinology, First Affiliated Hospital of Jinzhou Medical University, 121001, China
| | - Chang Liu
- Department of Endocrinology, First Affiliated Hospital of Jinzhou Medical University, 121001, China
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Kaleem A, Javed S, Rehman N, Abdullah R, Iqtedar M, Aftab MN, Hoessli DC, Haq IU. Phosphorylated and O-GlcNAc Modified IRS-1 (Ser1101) and -2 (Ser1149) Contribute to Human Diabetes Type II. Protein Pept Lett 2021; 28:333-339. [PMID: 32798372 DOI: 10.2174/0929866527666200813210407] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/09/2020] [Accepted: 06/11/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND The prevalence of the chronic metabolic disorder Type 2 diabetes mellitus (T2DM) is increasing steadily, and has even turned into an epidemic in some countries. T2DM results from defective responses to insulin and obesity is a major factor behind insulin resistance in T2DM. Insulin receptor substrate (IRS) proteins are adaptor proteins in the insulin receptor signalling pathway. The insulin signalling is controlled through tyrosine phosphorylation of IRS-1 and IRS-2, and dysregulation of IRS proteins signalling may lead to glucose intolerance and eventually insulin resistance. OBJECTIVE In this work, we suggest that both glycosylation (O-GlcNAc modification) and phosphorylation of IRS-1 and -2 are involved in the pathogenesis of T2DM. METHODS Phosphorylation and O-GlcNAc modifications (Ser1101 in IRS-1 and Ser1149 in IRS-2) proteins were determined experimentally by sandwich ELISA with specific antibodies and with bioinformatics tools. RESULTS When IRS-1 (on Ser1101) and IRS-2 (Ser1149) become glycosylated following an increase in UDP-GlcNAc pools, it may contribute to insulin resistance. Whereas when the same (IRS-1 on Ser1101 and IRS-2 on Ser1149) are phosphorylated, the insulin signalling is inhibited. DISCUSSION In this work OGlcNAc-modified proteins were specifically detected using O-Glc- NAc-specific antibodies, suggesting that elevated levels of O-GlcNAc-modified proteins are found, independently of their possible involvement in Advanced Glycation End products (AGEs). CONCLUSION This study suggests a mechanism, which is controlled by posttranslational modifications, and may contribute to the pathogenesis of type II diabetes.
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Affiliation(s)
- Afshan Kaleem
- Department of Biotechnology, Lahore College for Women University, Lahore, Punjab 54000, Pakistan
| | - Sabahat Javed
- Department of Biotechnology, Lahore College for Women University, Lahore, Punjab 54000, Pakistan
| | - Nayab Rehman
- Department of Biotechnology, Lahore College for Women University, Lahore, Punjab 54000, Pakistan
| | - Roheena Abdullah
- Department of Biotechnology, Lahore College for Women University, Lahore, Punjab 54000, Pakistan
| | - Mehwish Iqtedar
- Department of Biotechnology, Lahore College for Women University, Lahore, Punjab 54000, Pakistan
| | - Mohammad Nauman Aftab
- Institute of Industrial Biotechnology, Government College University, Lahore, Pakistan
| | - Daniel C Hoessli
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Ikram-Ul Haq
- Institute of Industrial Biotechnology, Government College University, Lahore, Pakistan
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9
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Kobayashi M, Zochodne DW. Diabetic polyneuropathy: Bridging the translational gap. J Peripher Nerv Syst 2021; 25:66-75. [PMID: 32573914 DOI: 10.1111/jns.12392] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 12/22/2022]
Abstract
Clinical trials for diabetic polyneuropathy (DPN) have failed to identify therapeutic impacts that have arrested or reversed the disorder, despite a long history. This review considers DPN in the context of a unique neurodegenerative disorder that targets peripheral neurons and their companion glial cells. The approach is to examine what cells, cell substructures, and pathways are implicated in causing DPN and how they might be addressed therapeutically. These include axonopathy, neuronopathy, hyperglycemia, polyol flux, advanced glycation endproduct (AGE)-receptor AGE signaling, growth factor disruption, abnormal insulin signaling, and abnormalities of other intrinsic neuron pathways. Mitochondrial dysfunction and lipid toxicity are largely delegated to the companion review in this issue by Stino and Feldman. Finally, the linkage between axon plasticity of cutaneous nerves, peripheral neuroregenerative pathways, and diabetes are discussed.
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Affiliation(s)
- Masaki Kobayashi
- Department of Neurology, Nissan Tamagawa Hospital, Tokyo, Japan.,Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Douglas W Zochodne
- Division of Neurology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
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10
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De Gregorio C, Ezquer F. Sensory neuron cultures derived from adult db/db mice as a simplified model to study type-2 diabetes-associated axonal regeneration defects. Dis Model Mech 2021; 14:dmm.046334. [PMID: 33262160 PMCID: PMC7847260 DOI: 10.1242/dmm.046334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 11/17/2020] [Indexed: 12/11/2022] Open
Abstract
Diabetic neuropathy (DN) is an early common complication of diabetes mellitus (DM), leading to chronic pain, sensory loss and muscle atrophy. Owing to its multifactorial etiology, neuron in vitro cultures have been proposed as simplified systems for DN studies. However, the most used models currently available do not recreate the chronic and systemic damage suffered by peripheral neurons of type-2 DM (T2DM) individuals. Here, we cultured neurons derived from dorsal root ganglia from 6-month-old diabetic db/db-mice, and evaluated their morphology by the Sholl method as an easy-to-analyze readout of neuronal function. We showed that neurons obtained from diabetic mice exhibited neuritic regeneration defects in basal culture conditions, compared to neurons from non-diabetic mice. Next, we evaluated the morphological response to common neuritogenic factors, including nerve growth factor NGF and Laminin-1 (also called Laminin-111). Neurons derived from diabetic mice exhibited reduced regenerative responses to these factors compared to neurons from non-diabetic mice. Finally, we analyzed the neuronal response to a putative DN therapy based on the secretome of mesenchymal stem cells (MSC). Neurons from diabetic mice treated with the MSC secretome displayed a significant improvement in neuritic regeneration, but still reduced when compared to neurons derived from non-diabetic mice. This in vitro model recapitulates many alterations observed in sensory neurons of T2DM individuals, suggesting the possibility of studying neuronal functions without the need of adding additional toxic factors to culture plates. This model may be useful for evaluating intrinsic neuronal responses in a cell-autonomous manner, and as a throughput screening for the pre-evaluation of new therapies for DN. Summary: Morphological characterization of a model for evaluating neuritic regeneration in vitro in dorsal root ganglion primary neurons derived from type-2 diabetic mice with an advanced stage of diabetic neuropathy.
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Affiliation(s)
- Cristian De Gregorio
- Center for Regenerative Medicine, School of Medicine Clínica Alemana-Universidad del Desarrollo, Santiago, 7690000 Chile
| | - Fernando Ezquer
- Center for Regenerative Medicine, School of Medicine Clínica Alemana-Universidad del Desarrollo, Santiago, 7690000 Chile
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11
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Mizukami H, Osonoi S, Takaku S, Yamagishi SI, Ogasawara S, Sango K, Chung S, Yagihashi S. Role of glucosamine in development of diabetic neuropathy independent of the aldose reductase pathway. Brain Commun 2020; 2:fcaa168. [PMID: 33305258 PMCID: PMC7713992 DOI: 10.1093/braincomms/fcaa168] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 08/04/2020] [Accepted: 08/24/2020] [Indexed: 12/30/2022] Open
Abstract
Long-term metabolic aberrations contribute to the development of diabetic neuropathy but the precise mechanism or mechanisms remains elusive. We have previously shown that aldose reductase-deficient mice exhibit delayed onset and progression of neuropathy following induction of diabetes, suggesting a role both for downstream metabolites of this enzyme and also for other unrelated pathways. In this study, we have utilized comprehensive metabolomics analyses to identify potential neurotoxic metabolites in nerve of diabetic mice and explored the mechanism of peripheral nerve injury. Aldose reductase knockout and control C57Bl/6J mice were made diabetic by injection of streptozotocin and followed for 8–16 weeks. Diabetic aldose reductase knockout mice exhibited delayed onset of nerve conduction slowing compared to diabetic wild-type mice. The sciatic nerves from aldose reductase knockout mice exposed to 12 weeks of diabetes were used for metabolomics analysis and compared with analyses of nerves from age-matched diabetic wild-type mice as well as non-diabetic aldose reductase knockout and wild-type mice. Neurotoxicity of candidate metabolites was evaluated using cultured Schwann cells and dorsal root ganglion neurons, and further confirmed in vivo. Metabolomics analysis identified elevated glucosamine levels in both diabetic aldose reductase knockout and diabetic wild mice. Exposure to glucosamine reduced survival of cultured Schwann cells and neurons accompanied by increased expression of cleaved caspase 3, CCAT-enhancer-binding homologous protein and mitochondrial hexokinase-I, along with ATP depletion. These changes were suppressed by siRNA to hexokinase-I or the ATP donor, inosine, but not by the antioxidant N-acetylcysteine or the endoplasmic reticulum-stress inhibitor 4-phenylbutyrate. The O-GlcNAcylation enhancer, O-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino N-phenylcarbamate, did not augment glucosamine neurotoxicity. Single dose glucosamine injection into mice caused a reduction of sciatic nerve Na, K-ATPase activity, ATP content and augmented expression of hexokinase-I, which were suppressed by pretreatment with inosine but not with 4-phenylbutyrate. Mice implanted with a subcutaneous pump to infuse glucosamine for 12 weeks developed nerve conduction slowing and intraepidermal nerve fibre loss, recapitulating prominent indices of diabetic neuropathy. While acute glucosamine neurotoxicity is unlikely to contribute substantially to the slowly developing neuropathy phenotype in humans, sustained energy deprivation induced by glucosamine may well contribute to the pathogenesis of diabetic neuropathy. Our data thus identifies a novel pathway for diabetic neuropathy that may offer a potential new therapeutic target.
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Affiliation(s)
- Hiroki Mizukami
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Sho Osonoi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Shizuka Takaku
- Diabetic Neuropathy Project, Tokyo Metropolitan Institute of Medical Science, Tokyo
| | - Shin-Ichiro Yamagishi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Saori Ogasawara
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Kazunori Sango
- Diabetic Neuropathy Project, Tokyo Metropolitan Institute of Medical Science, Tokyo
| | - Sookja Chung
- Faculty of Medicine, Macau University of Science and Technology, Taipa, Macau
| | - Soroku Yagihashi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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12
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Guo K, Eid SA, Elzinga SE, Pacut C, Feldman EL, Hur J. Genome-wide profiling of DNA methylation and gene expression identifies candidate genes for human diabetic neuropathy. Clin Epigenetics 2020; 12:123. [PMID: 32787975 PMCID: PMC7425575 DOI: 10.1186/s13148-020-00913-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/27/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Diabetic peripheral neuropathy (DPN) is the most common complication of type 2 diabetes (T2D). Although the cellular and molecular mechanisms of DPN are poorly understood, we and others have shown that altered gene expression and DNA methylation are implicated in disease pathogenesis. However, how DNA methylation might functionally impact gene expression and contribute to nerve damage remains unclear. Here, we analyzed genome-wide transcriptomic and methylomic profiles of sural nerves from T2D patients with DPN. RESULTS Unbiased clustering of transcriptomics data separated samples into groups, which correlated with HbA1c levels. Accordingly, we found 998 differentially expressed genes (DEGs) and 929 differentially methylated genes (DMGs) between the groups with the highest and lowest HbA1c levels. Functional enrichment analysis revealed that DEGs and DMGs were enriched for pathways known to play a role in DPN, including those related to the immune system, extracellular matrix (ECM), and axon guidance. To understand the interaction between the transcriptome and methylome in DPN, we performed an integrated analysis of the overlapping genes between DEGs and DMGs. Integrated functional and network analysis identified genes and pathways modulating functions such as immune response, ECM regulation, and PI3K-Akt signaling. CONCLUSION These results suggest for the first time that DNA methylation is a mechanism regulating gene expression in DPN. Overall, DPN patients with high HbA1c have distinct alterations in sural nerve DNA methylome and transcriptome, suggesting that optimal glycemic control in DPN patients is an important factor in maintaining epigenetic homeostasis and nerve function.
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Affiliation(s)
- Kai Guo
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, 1301 North Columbia Rd. Stop 9037, Grand Forks, ND 58202-9037 USA
| | - Stephanie A. Eid
- Department of Neurology, School of Medicine, University of Michigan, Ann Arbor, MI 48109 USA
| | - Sarah E. Elzinga
- Department of Neurology, School of Medicine, University of Michigan, Ann Arbor, MI 48109 USA
| | - Crystal Pacut
- Department of Neurology, School of Medicine, University of Michigan, Ann Arbor, MI 48109 USA
| | - Eva L. Feldman
- Department of Neurology, School of Medicine, University of Michigan, Ann Arbor, MI 48109 USA
| | - Junguk Hur
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, 1301 North Columbia Rd. Stop 9037, Grand Forks, ND 58202-9037 USA
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13
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Abstract
PURPOSE OF REVIEW The current review addresses one of the most common neurological disorders, diabetic polyneuropathy (DPN). DPN is debilitating, irreversible and dwarfs the prevalence of most other chronic disorders of the nervous system. Its complications include foot ulceration, amputation, falling and intractable neuropathic pain. Moreover, tight control of hyperglycemia reduces the incidence of DPN in type 1 diabetes mellitus but its role in type 2 diabetes mellitus is less clear. RECENT FINDINGS New therapeutic options to reverse the development of DPN or its associated pain have been proposed but none have significantly changed the clinical approach. The cause of DPN remains controversial traditionally focused on the impact of metabolic abnormalities, polyol flux, microvascular changes, mitochondria, oxidative stress, lipid biology and others. In particular, there has been less attention toward how this chronic disorder alters peripheral neurobiology. It is now clear that in chronic models of diabetes mellitus there exists a unique form of neurodegeneration with a range of protein, mRNA and microRNA alterations to consider. How to reconcile these molecular and structural alterations with metabolic mechanisms is a challenge. In sensory neurons alone, a primary target of DPN, both central perikaryal cytoplasmic and nuclear changes and altered distal sensory axon terminal plasticity may be involved. SUMMARY In this review, the current therapeutic status of DPN is described with greater emphasis on some new but selected thoughts on its neurobiology. New mechanistic understanding will be essential to developing precision therapeutics for DPN.
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Joo J, Jung SH, Yu KH, Cheon HG. Synthesis and Biological Evaluation of Decursinol Derivatives as FoxO‐1 Inhibitors in HepG2 Cells. B KOREAN CHEM SOC 2019. [DOI: 10.1002/bkcs.11815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Jeong‐Ho Joo
- Samjin pharm. Co., Ltd Seongnam 13488 Republic of Korea
- Department of ChemistryDongguk University‐Seoul Seoul 04620 Republic of Korea
| | - Sun Hwa Jung
- Center for Innovative Drug Library Research, Department of ChemistryCollege of Science Dongguk University Seoul 04620 Republic of Korea
| | - Kook Hyun Yu
- Department of ChemistryDongguk University‐Seoul Seoul 04620 Republic of Korea
| | - Hyae Gyeong Cheon
- Department of PharmacologySchool of Medicine, Gachon University Incheon 21999 Republic of Korea
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15
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Abstract
The global epidemic of prediabetes and diabetes has led to a corresponding epidemic of complications of these disorders. The most prevalent complication is neuropathy, of which distal symmetric polyneuropathy (for the purpose of this Primer, referred to as diabetic neuropathy) is very common. Diabetic neuropathy is a loss of sensory function beginning distally in the lower extremities that is also characterized by pain and substantial morbidity. Over time, at least 50% of individuals with diabetes develop diabetic neuropathy. Glucose control effectively halts the progression of diabetic neuropathy in patients with type 1 diabetes mellitus, but the effects are more modest in those with type 2 diabetes mellitus. These findings have led to new efforts to understand the aetiology of diabetic neuropathy, along with new 2017 recommendations on approaches to prevent and treat this disorder that are specific for each type of diabetes. In parallel, new guidelines for the treatment of painful diabetic neuropathy using distinct classes of drugs, with an emphasis on avoiding opioid use, have been issued. Although our understanding of the complexities of diabetic neuropathy has substantially evolved over the past decade, the distinct mechanisms underlying neuropathy in type 1 and type 2 diabetes remains unknown. Future discoveries on disease pathogenesis will be crucial to successfully address all aspects of diabetic neuropathy, from prevention to treatment.
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16
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Feldman EL, Callaghan BC, Pop-Busui R, Zochodne DW, Wright DE, Bennett DL, Bril V, Russell JW, Viswanathan V. Diabetic neuropathy. Nat Rev Dis Primers 2019; 5:42. [PMID: 31197183 PMCID: PMC7096070 DOI: 10.1038/s41572-019-0097-9] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The global epidemic of prediabetes and diabetes has led to a corresponding epidemic of complications of these disorders. The most prevalent complication is neuropathy, of which distal symmetric polyneuropathy (for the purpose of this Primer, referred to as diabetic neuropathy) is very common. Diabetic neuropathy is a loss of sensory function beginning distally in the lower extremities that is also characterized by pain and substantial morbidity. Over time, at least 50% of individuals with diabetes develop diabetic neuropathy. Glucose control effectively halts the progression of diabetic neuropathy in patients with type 1 diabetes mellitus, but the effects are more modest in those with type 2 diabetes mellitus. These findings have led to new efforts to understand the aetiology of diabetic neuropathy, along with new 2017 recommendations on approaches to prevent and treat this disorder that are specific for each type of diabetes. In parallel, new guidelines for the treatment of painful diabetic neuropathy using distinct classes of drugs, with an emphasis on avoiding opioid use, have been issued. Although our understanding of the complexities of diabetic neuropathy has substantially evolved over the past decade, the distinct mechanisms underlying neuropathy in type 1 and type 2 diabetes remains unknown. Future discoveries on disease pathogenesis will be crucial to successfully address all aspects of diabetic neuropathy, from prevention to treatment.
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Affiliation(s)
- Eva L. Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA.,
| | | | - Rodica Pop-Busui
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes (MEND), University of Michigan, Ann Arbor, MI, USA
| | - Douglas W. Zochodne
- Division of Neurology, Department of Medicine and the Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Douglas E. Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - David L. Bennett
- Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, UK
| | - Vera Bril
- Division of Neurology, Department of Medicine, University of Toronto and University Health Network, Toronto, Ontario, Canada.,Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - James W. Russell
- Department of Neurology, University of Maryland and VA Maryland Health Care System, Baltimore, MD, USA
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17
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de Mello NP, Orellana AM, Mazucanti CH, de Morais Lima G, Scavone C, Kawamoto EM. Insulin and Autophagy in Neurodegeneration. Front Neurosci 2019; 13:491. [PMID: 31231176 PMCID: PMC6558407 DOI: 10.3389/fnins.2019.00491] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 04/29/2019] [Indexed: 12/12/2022] Open
Abstract
Crosstalk in the pathophysiological processes underpinning metabolic diseases and neurodegenerative disorders have been the subject of extensive investigation, in which insulin signaling and autophagy impairment demonstrate to be a common factor in both conditions. Although it is still somewhat conflicting, pharmacological and genetic strategies that regulate these pathways may be a promising approach for aggregate protein clearancing and consequently the delaying of onset or progression of the disease. However, as the response due to this modulation seems to be time-dependent, finding the right regulation of autophagy may be a potential target for drug development for neurodegenerative diseases. In this way, this review focuses on the role of insulin signaling/resistance and autophagy in some neurodegenerative diseases, discussing pharmacological and non-pharmacological interventions in these diseases.
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Affiliation(s)
- Natália Prudente de Mello
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Ana Maria Orellana
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Caio Henrique Mazucanti
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Geovanni de Morais Lima
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Cristoforo Scavone
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Elisa Mitiko Kawamoto
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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18
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García G, Gutiérrez-Lara EJ, Centurión D, Granados-Soto V, Murbartián J. Fructose-Induced Insulin Resistance as a Model of Neuropathic Pain in Rats. Neuroscience 2019; 404:233-245. [DOI: 10.1016/j.neuroscience.2019.01.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 12/21/2022]
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19
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Kobayashi M, Zochodne DW. Diabetic neuropathy and the sensory neuron: New aspects of pathogenesis and their treatment implications. J Diabetes Investig 2018; 9:1239-1254. [PMID: 29533535 PMCID: PMC6215951 DOI: 10.1111/jdi.12833] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/20/2018] [Accepted: 03/03/2018] [Indexed: 12/17/2022] Open
Abstract
Diabetic polyneuropathy (DPN) continues to be generally considered as a "microvascular" complication of diabetes mellitus alongside nephropathy and retinopathy. The microvascular hypothesis, however, might be tempered by the concept that diabetes directly targets dorsal root ganglion sensory neurons. This neuron-specific concept, supported by accumulating evidence, might account for important features of DPN, such as its early sensory neuron degeneration. Diabetic sensory neurons develop neuronal atrophy alongside a series of messenger ribonucleic acid (RNA) changes related to declines in structural proteins, increases in heat shock protein, increases in the receptor for advanced glycation end-products, declines in growth factor signaling and other changes. Insulin is recognized as a potent neurotrophic factor, and insulin ligation enhances neurite outgrowth through activation of the phosphoinositide 3-kinase-protein kinase B pathway within sensory neurons and attenuates phenotypic features of experimental DPN. Several interventions, including glucagon-like peptide-1 agonism, and phosphatase and tensin homolog inhibition to activate growth signals in sensory neurons, or heat shock protein overexpression, prevent or reverse neuropathic abnormalities in experimental DPN. Diabetic sensory neurons show a unique pattern of microRNA alterations, a key element of messenger RNA silencing. For example, let-7i is widely expressed in sensory neurons, supports their growth and is depleted in experimental DPN; its replenishment improves features of DPN models. Finally, impairment of pre-messenger RNA splicing in diabetic sensory neurons including abnormal nuclear RNA metabolism and structure with loss of survival motor neuron protein, a neuron survival molecule, and overexpression of CWC22, a splicing factor, offer further novel insights. The present review addresses these new aspects of DPN sensory neurodegeneration.
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Affiliation(s)
- Masaki Kobayashi
- Department of Neurology and Neurological ScienceGraduate School of MedicineTokyo Medical and Dental UniversityTokyoJapan
- Department of NeurologyYokufukai Geriatric HospitalTokyoJapan
| | - Douglas W Zochodne
- Division of Neurology and Department of MedicineNeuroscience and Mental Health InstituteFaculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
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20
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Manu MS, Rachana KS, Advirao GM. The correlation between insulin and OCT-6 transcription factor in Schwann cells and sciatic nerve of diabetic rats. Genes Dis 2018; 5:130-136. [PMID: 30258942 PMCID: PMC6147042 DOI: 10.1016/j.gendis.2017.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 12/11/2017] [Indexed: 11/26/2022] Open
Abstract
Insulin signal is one of the vital signaling cascade required for Schwann cells to myelinate the axons of peripheral nervous system (PNS). Myelin formation of peripheral nerve is a complex molecular event controlled by different neurotrophic and transcription factors. The altered or failure in this signaling progression is one of the reasons behind the demyelination of peripheral neurons in diabetic peripheral neuropathy (DPN). The Schwann cell in PNS includes POU domain transcription factor OCT-6 expression. This factor is considered as crucial for the initiation and enhancement of myelination during nerve regeneration. To know the importance of OCT-6 gene, here we studied the long term expression of OCT-6 nuclear protein in sciatic nerve of normal and diabetic neuropathic rats. Also for the first time we elucidated the role of insulin in controlling the expression of OCT-6 in hyperglycemic Schwann cells and sciatic nerve of diabetic neuropathic rats. The results shows that, there will be long term OCT-6 expression in sciatic nerve of adult rats and also their significant decrease is observed in the diabetic condition. But, addition of Insulin for primary Schwann cells and diabetic rats shows the increased OCT-6 expression in both invivo and invitro. Together these results indicate the failure of OCT-6 support in neuropathy and also the importance of insulin signaling cascade in the expression of OCT-6 transcription factor.
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Affiliation(s)
- Mallahalli S Manu
- Department of Biochemistry, Davangere University, Davangere, Karnataka, India
| | | | - Gopal M Advirao
- Department of Biochemistry, Davangere University, Davangere, Karnataka, India
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21
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Grote CW, Wilson NM, Katz NK, Guilford BL, Ryals JM, Novikova L, Stehno-Bittel L, Wright DE. Deletion of the insulin receptor in sensory neurons increases pancreatic insulin levels. Exp Neurol 2018; 305:97-107. [PMID: 29649429 PMCID: PMC5963702 DOI: 10.1016/j.expneurol.2018.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 11/24/2022]
Abstract
Insulin is known to have neurotrophic properties and loss of insulin support to sensory neurons may contribute to peripheral diabetic neuropathy (PDN). Here, genetically-modified mice were generated in which peripheral sensory neurons lacked the insulin receptor (SNIRKO mice) to determine whether disrupted sensory neuron insulin signaling plays a crucial role in the development of PDN and whether SNIRKO mice develop symptoms of PDN due to reduced insulin neurotrophic support. Our results revealed that SNIRKO mice were euglycemic and never displayed significant changes in a wide range of sensorimotor behaviors, nerve conduction velocity or intraepidermal nerve fiber density. However, SNIRKO mice displayed elevated serum insulin levels, glucose intolerance, and increased insulin content in the islets of Langerhans of the pancreas. These results contribute to the growing idea that sensory innervation of pancreatic islets is key to regulating islet function and that a negative feedback loop of sensory neuron insulin signaling keeps this regulation in balance. Our results suggest that a loss of insulin receptors in sensory neurons does not lead to peripheral nerve dysfunction. The SNIRKO mice will be a powerful tool to investigate sensory neuron insulin signaling and may give a unique insight into the role that sensory neurons play in modifying islet physiology.
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Affiliation(s)
- Caleb W Grote
- Department of Orthopedic Surgery, University of Kansas Medical Center, United States
| | - Natalie M Wilson
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, United States
| | - Natalie K Katz
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, United States
| | - Brianne L Guilford
- Department of Applied Health, Southern Illinois University Edwardsville, United States
| | - Janelle M Ryals
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, United States
| | - Lesya Novikova
- Physical Therapy & Rehabilitation Science, University of Kansas Medical Center, Southern Illinois University Edwardsville, United States
| | - Lisa Stehno-Bittel
- Physical Therapy & Rehabilitation Science, University of Kansas Medical Center, Southern Illinois University Edwardsville, United States
| | - Douglas E Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, United States.
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22
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Ribes-Navarro A, Atef M, Sánchez-Sarasúa S, Beltrán-Bretones MT, Olucha-Bordonau F, Sánchez-Pérez AM. Abscisic Acid Supplementation Rescues High Fat Diet-Induced Alterations in Hippocampal Inflammation and IRSs Expression. Mol Neurobiol 2018; 56:454-464. [PMID: 29721854 DOI: 10.1007/s12035-018-1091-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/17/2018] [Indexed: 01/04/2023]
Abstract
Accumulated evidence indicates that neuroinflammation induces insulin resistance in the brain. Moreover, both processes are intimately linked to neurodegenerative disorders, including Alzheimer's disease. Potential mechanisms underlying insulin resistance include serine phosphorylation of the insulin receptor substrate (IRS) or insulin receptor (IR) misallocation. However, only a few studies have focused on IRS expression in the brain and its modulation in neuroinflammatory processes. This study used the high-fat diet (HFD) model of neuroinflammation to study the alterations of IR, an insulin-like growth factor receptor (IGF1R) and IRS expressions in the hippocampus. We observed that HFD effectively reduced mRNA and protein IRS2 expression. In contrast, a HFD induced the upregulation of the IRS1 mRNA levels, but did not alter an IR and IGF1R expression. As expected, we observed that a HFD increased hippocampal tumor necrosis factor alpha (TNFα) and amyloid precursor protein (APP) levels while reducing brain-derived neurotrophic factor (BDNF) expression and neurogenesis. Interestingly, we found that TNFα correlated positively with IRS1 and negatively with IRS2, whereas APP levels correlated positively only with IRS1 but not IRS2. These results indicate that IRS1 and IRS2 hippocampal expression can be affected differently by HFD-induced neuroinflammation. In addition, we aimed to establish whether abscisic acid (ABA) can rescue hippocampal IRS1 and IRS2 expression, as we had previously shown that ABA supplementation prevents memory impairments and improves neuroinflammation induced by a HFD. In this study, ABA restored HFD-induced hippocampal alterations, including IRS1 and IRS2 expression, TNFα, APP, and BDNF levels and neurogenesis. In conclusion, this study highlights different regulations of hippocampal IRS1 and IRS2 expression using a HFD, indicating the important differences of these scaffolding proteins, and strongly supports ABA therapeutic effects.
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Affiliation(s)
| | - Mariam Atef
- Department of Medicine, University of Jaume I, Castellón de la Plana, Spain
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23
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de la Hoz CL, Cheng C, Fernyhough P, Zochodne DW. A model of chronic diabetic polyneuropathy: benefits from intranasal insulin are modified by sex and RAGE deletion. Am J Physiol Endocrinol Metab 2017; 312:E407-E419. [PMID: 28223295 PMCID: PMC5451527 DOI: 10.1152/ajpendo.00444.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/06/2017] [Accepted: 02/18/2017] [Indexed: 01/11/2023]
Abstract
Human diabetic polyneuropathy (DPN) is a progressive complication of chronic diabetes mellitus. Preliminary evidence has suggested that intranasal insulin, in doses insufficient to alter hyperglycemia, suppresses the development of DPN. In this work we confirm this finding, but demonstrate that its impact is modified by sex and deletion of RAGE, the receptor for advanced glycosylation end products. We serially evaluated experimental DPN in male and female wild-type mice and male RAGE null (RN) mice, each with nondiabetic controls, during 16 wk of diabetes, the final 8 wk including groups given intranasal insulin. Age-matched nondiabetic female mice had higher motor and sensory conduction velocities than their male counterparts and had lesser conduction slowing from chronic diabetes. Intranasal insulin improved slowing in both sexes. In male RN mice, there was less conduction slowing with chronic diabetes, and intranasal insulin provided limited benefits. Rotarod testing and hindpaw grip power offered less consistent impacts. Mechanical sensitivity and thermal sensitivity were respectively but disparately changed and improved with insulin in wild-type female and male mice but not RN male mice. These studies confirm that intranasal insulin improves indexes of experimental DPN but indicates that females with DPN may differ in their underlying phenotype. RN mice had partial but incomplete protection from underlying DPN and lesser impacts from insulin. We also identify an important role for sex in the development of DPN and report evidence that insulin and AGE-RAGE pathways in its pathogenesis may overlap.
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Affiliation(s)
- Cristiane L de la Hoz
- Department of Clinical Neurosciences, the Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; and
| | - Chu Cheng
- Department of Clinical Neurosciences, the Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; and
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre and Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Douglas W Zochodne
- Division of Neurology, Department of Medicine, Neuroscience and Mental Health Institute, Alberta Diabetes Institute, University of Alberta, Alberta, Canada;
- Department of Clinical Neurosciences, the Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; and
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24
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Manu MS, Rachana KS, Advirao GM. Altered expression of IRS2 and GRB2 in demyelination of peripheral neurons: Implications in diabetic neuropathy. Neuropeptides 2017; 62:71-79. [PMID: 28065675 DOI: 10.1016/j.npep.2016.12.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/28/2016] [Accepted: 12/12/2016] [Indexed: 10/20/2022]
Abstract
Demyelination of the peripheral nerves and dysfunction of Schwann cells (SCs) are the chronic complications involved in the development of peripheral neuropathy among diabetic patients. Insulin signaling plays an important role in restoring the myelin proteins in diabetic peripheral neuropathy (DPN). Since insulin levels are altered in diabetes, it becomes of great interest to appreciate the role and regulation of docking and adaptor protein, how these proteins respond to variations in the levels of insulin as experienced in juvenile diabetes. Tyrosine phosphorylation of receptor protein kinases provides a docking site for the activation of adaptor proteins which are the key regulators of insulin signaling pathway. In this report, we studied the long term effect of insulin as a neurotrophic factor and identified the isoform of receptor substrate involved in the propagation of insulin signal in SCs. We also studied the ability of insulin to regulate the expression of different receptor substrates like insulin receptor substrate-1 (IRS1), insulin receptor substrate-2 (IRS2) and growth factor receptor-bound protein-2 (GRB2) that propagate the insulin signaling and also their variation in hyperglycemic SCs and sciatic nerve of the diabetic rats. Results confirmed that IRS2 is the key receptor substrate involved in insulin signal transduction. But, a radical increase in the phosphorylation of IRS2 at serine 731 prevents the recruitment of GRB2 adaptor protein which may fail further to connect the Ras and other pathways required to the cell for its survival and to maintain integrity. These findings prove that SCs and sciatic nerve express IRS proteins that are altered by diabetes and thereby insulin signaling downstream is impaired and that contribute to the pathogenesis of DPN.
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Affiliation(s)
- Mallahalli S Manu
- Department of Biochemistry, Davangere University, Davangere, Karnataka, India
| | | | - Gopal M Advirao
- Department of Biochemistry, Davangere University, Davangere, Karnataka, India.
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25
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Guilford BL, Ryals JM, Lezi E, Swerdlow RH, Wright DE. Dorsal Root Ganglia Mitochondrial Biochemical Changes in Non-diabetic and Streptozotocin-Induced Diabetic Mice Fed with a Standard or High-Fat Diet. ACTA ACUST UNITED AC 2017; 8. [PMID: 28775932 DOI: 10.21767/2171-6625.1000180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Mitochondrial dysfunction is purported as a contributory mechanism underlying diabetic neuropathy, but a defined role for damaged mitochondria in diabetic nerves remains unclear, particularly in standard diabetes models. Experiments here used a high-fat diet in attempt to exacerbate the severity of diabetes and expedite the time-course in which mitochondrial dysfunction may occur. We hypothesized a high-fat diet in addition to diabetes would increase stress on sensory neurons and worsen mitochondrial dysfunction. METHODS Oxidative phosphorylation proteins and proteins associated with mitochondrial function were quantified in lumbar dorsal root ganglia. Comparisons were made between non-diabetic and streptozotocin-induced (STZ) C57Bl/6 mice fed a standard or high-fat diet for 8 weeks. RESULTS Complex III subunit Core-2 and voltage dependent anion channel were increased (by 36% and 28% respectively, p<0.05) in diabetic mice compared to nondiabetic mice fed the standard diet. There were no differences among groups in UCP2, PGC-1α, PGC-1β levels or Akt, mTor, or AMPK activation. These data suggest compensatory mitochondrial biogenesis occurs to offset potential mitochondrial dysfunction after 8 weeks of STZ-induced diabetes, but a high-fat diet does not alter these parameters. CONCLUSION Our results indicate mitochondrial protein changes early in STZ-induced diabetes. Interestingly, a high-fat diet does not appear to affect mitochondrial proteins in either nondiabetic or STZ- diabetic mice.
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Affiliation(s)
- B L Guilford
- Department of Applied Health, Southern Illinois University, Edwardsville, Illinois, USA
| | - J M Ryals
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - E Lezi
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
| | - R H Swerdlow
- Department of Molecular and Integrative Physiology and Neurology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - D E Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
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26
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Perez-Matos MC, Morales-Alvarez MC, Mendivil CO. Lipids: A Suitable Therapeutic Target in Diabetic Neuropathy? J Diabetes Res 2017; 2017:6943851. [PMID: 28191471 PMCID: PMC5278202 DOI: 10.1155/2017/6943851] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/23/2016] [Accepted: 12/13/2016] [Indexed: 12/14/2022] Open
Abstract
Diabetic polyneuropathy (DPN) encompasses multiple syndromes with a common pathogenesis. Glycemic control shows a limited correlation with DPN, arguing in favor of major involvement of other factors, one of which is alterations of lipid and lipoprotein metabolism. Consistent associations have been found between plasma triglycerides/remnant lipoproteins and the risk of DPN. Studies in cultured nerve tissue or in murine models of diabetes have unveiled mechanisms linking lipid metabolism to DPN. Deficient insulin action increases fatty acids flux to nerve cells, inducing mitochondrial dysfunction, anomalous protein kinase C signaling, and perturbations in the physicochemical properties of the plasma membrane. Oxidized low-density lipoproteins bind to cellular receptors and promote generation of reactive oxygen species, worsening mitochondrial function and altering the electrical properties of neurons. Supplementation with specific fatty acids has led to prevention or reversal of different modalities of DPN in animal models. Post hoc and secondary analyses of clinical trials have found benefits of cholesterol reducing (statins and ezetimibe), triglyceride-reducing (fibrates), or lipid antioxidant (thioctic acid) therapies over the progression and severity of DPN. However, these findings are mostly hypothesis-generating. Randomized trials are warranted in which the impact of intensive plasma lipids normalization on DPN outcomes is specifically evaluated.
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Affiliation(s)
| | | | - C. O. Mendivil
- School of Medicine, Universidad de Los Andes, Bogotá, Colombia
- Fundación Santa Fe de Bogotá, Department of Internal Medicine, Section of Endocrinology, Bogotá, Colombia
- *C. O. Mendivil:
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27
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Grote CW, Wright DE. A Role for Insulin in Diabetic Neuropathy. Front Neurosci 2016; 10:581. [PMID: 28066166 PMCID: PMC5179551 DOI: 10.3389/fnins.2016.00581] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 12/06/2016] [Indexed: 12/13/2022] Open
Abstract
The peripheral nervous system is one of several organ systems that are profoundly affected in diabetes. The longstanding view is that insulin does not have a major role in modulating neuronal function in both central and peripheral nervous systems is now being challenged. In the setting of insulin deficiency or excess insulin, it is logical to propose that insulin dysregulation can contribute to neuropathic changes in sensory neurons. This is particularly important as sensory nerve damage associated with prediabetes, type 1 and type 2 diabetes is so prevalent. Here, we discuss the current experimental literature related to insulin's role as a potential neurotrophic factor in peripheral nerve function, as well as the possibility that insulin deficiency plays a role in diabetic neuropathy. In addition, we discuss how sensory neurons in the peripheral nervous system respond to insulin similar to other insulin-sensitive tissues. Moreover, studies now suggest that sensory neurons can also become insulin resistant like other tissues. Collectively, emerging studies are revealing that insulin signaling pathways are active contributors to sensory nerve modulation, and this review highlights this novel activity and should provide new insight into insulin's role in both peripheral and central nervous system diseases.
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Affiliation(s)
- Caleb W Grote
- Department of Anatomy and Cell Biology, University of Kansas Medical Center Kansas City, KS, USA
| | - Douglas E Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center Kansas City, KS, USA
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28
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Abstract
IRS proteins are cellular adaptor molecules that mediate many of the key metabolic actions of insulin. When tyrosine is phosphorylated by the activated insulin receptor, IRS proteins recruit downstream effectors, such as phosphoinositide 3-kinase and mitogen-activated protein kinase, in order to elicit cellular responses such as glucose uptake, lipid metabolism and cell proliferation. There are two main IRS proteins in humans (IRS1 and IRS2), both of which are widely expressed. Given their central role in the insulin signalling pathway, it is not surprising that male mice lacking Irs1 or Irs2 present with elevated blood glucose or type 2 diabetes, respectively. For reasons yet to be identified, female Irs2 (-/-) mice do not develop type 2 diabetes. A number of organs are affected by complications of diabetes; macrovascular complications include stroke and coronary artery disease, while nephropathy, neuropathy and retinopathy fall into the category of microvascular complications. Given the serious consequences of these complications on patient morbidity and mortality, it is essential to identify the molecular pathogenesis underlying diabetic complications, with a view to improving therapeutic intervention and patient outcomes. A number of recently published papers have converged on the hypothesis that the loss of insulin signalling and IRS proteins is instrumental to the development and/or progression of diabetic complications. This review will summarise some highlights from the published work in which this hypothesis is discussed.
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Affiliation(s)
- Deborah P Lavin
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, UK
| | - Morris F White
- Division of Endocrinology, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
| | - Derek P Brazil
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, UK.
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29
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Xu H, Liu C, Rao S, He L, Zhang T, Sun S, Wu B, Zou L, Wang S, Xue Y, Jia T, Zhao S, Li G, Liu S, Li G, Liang S. LncRNA NONRATT021972 siRNA rescued decreased heart rate variability in diabetic rats in superior cervical ganglia. Auton Neurosci 2016; 201:1-7. [PMID: 27519467 DOI: 10.1016/j.autneu.2016.07.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 06/23/2016] [Accepted: 07/31/2016] [Indexed: 12/23/2022]
Abstract
Diabetic cardiac autonomic neuropathy (DCAN) is a serious and common complication in diabetes mellitus (DM). Long noncoding RNAs (lncRNAs), an important class of regulatory molecules in diverse biological processes, have attracted considerable interest in DCAN. Our previous study has indicated a lncRNA, NONRATT021972 (NONCODE ID), was enhanced in sympathetic neuronal-like PC12 cells in the setting of high glucose (HG) and high FFAs (HF); its silence was found to significantly alleviate HGHF-induced tumor necrosis factor-α (TNF-α) release in PC12 cells. Here we further explore the effects of NONRATT021972 small interference RNA (siRNA) on heart rate variability (HRV) mediated by superior cervical ganglia (SCG) in diabetic rats and the possible mechanism underlying. We found an increment of NONRATT021972 in SCG of DM rats. Treatment of NONRATT021972 siRNA in DM rats decreased the elevated expression of TNF-α, blocked serine phosphorylation of insulin receptor substrate (IRS) 1 and increased the down-regulated expression of IRS1 in SCG. Meanwhile, NONRATT021972 siRNA rescued decreased HRV in DM rats. Therefore, inhibition of NONRATT021972 may serve as a novel therapeutic strategy for preventing the development of DCAN.
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Affiliation(s)
- Hong Xu
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Changle Liu
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Shenqiang Rao
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Luling He
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Tengling Zhang
- Nanchang Institute of Science and Technology, Nanchang, Jiangxi 330006, PR China
| | - Shanshan Sun
- Second Clinical Medical College, Medical College of Nanchang University, Nanchang, 330008, P.R., China
| | - Bing Wu
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Lifang Zou
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Shouyu Wang
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Yun Xue
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Tianyu Jia
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Shanhong Zhao
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Guilin Li
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Shuangmei Liu
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | - Guodong Li
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China; Department of Clinical Research, Singapore General Hospital, Singapore
| | - Shangdong Liang
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China.
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30
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Feng HL, Dang HZ, Fan H, Chen XP, Rao YX, Ren Y, Yang JD, Shi J, Wang PW, Tian JZ. Curcumin ameliorates insulin signalling pathway in brain of Alzheimer's disease transgenic mice. Int J Immunopathol Pharmacol 2016; 29:734-741. [PMID: 27466310 DOI: 10.1177/0394632016659494] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 06/22/2016] [Indexed: 01/24/2023] Open
Abstract
Deficits in glucose, impaired insulin signalling and brain insulin resistance are common in the pathogenesis of Alzheimer's disease (AD); therefore, some scholars even called AD type 3 diabetes mellitus. Curcumin can reduce the amyloid pathology in AD. Moreover, it is a well-known fact that curcumin has anti-oxidant and anti-inflammatory properties. However, whether or not curcumin could regulate the insulin signal transduction pathway in AD remains unclear. In this study, we used APPswe/PS1dE9 double transgenic mice as the AD model to investigate the mechanisms and the effects of curcumin on AD. Immunohistochemical (IHC) staining and a western blot analysis were used to test the major proteins in the insulin signal transduction pathway. After the administration of curcumin for 6 months, the results showed that the expression of an insulin receptor (InR) and insulin receptor substrate (IRS)-1 decreased in the hippocampal CA1 area of the APPswe/PS1dE9 double transgenic mice, while the expression of phosphatidylinositol-3 kinase (PI3K), phosphorylated PI3K (p-PI3K), serine-threonine kinase (AKT) and phosphorylated AKT (p-AKT) increased. Among the curcumin groups, the medium-dose group was the most effective one. Thus, we believe that curcumin may be a potential therapeutic agent that can regulate the critical molecules in brain insulin signalling pathways. Furthermore, curcumin could be adopted as one of the AD treatments to improve a patient's learning and memory ability.
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Affiliation(s)
- Hui-Li Feng
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), PR China.,Key Laboratory of Pharmacology of State Administration of Traditional Chinese Medicine, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, PR China
| | - Hui-Zi Dang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), PR China.,Pneumology Department, Huimin Hospital, Beijing, PR China
| | - Hui Fan
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), PR China.,Beijing Chaoyang Combine Traditional Chinese and Western Medicine Emergency Medical Center, Beijing, PR China
| | - Xiao-Pei Chen
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), PR China.,Kaifeng Hospital of Traditional Chinese Medicine, Kaifeng, PR China
| | | | - Ying Ren
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), PR China.,Key Laboratory of Pharmacology of State Administration of Traditional Chinese Medicine, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, PR China
| | - Jin-Duo Yang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), PR China.,Key Laboratory of Pharmacology of State Administration of Traditional Chinese Medicine, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, PR China
| | - Jing Shi
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), PR China.,BUCM Neurology Center, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, PR China
| | - Peng-Wen Wang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), PR China .,Key Laboratory of Pharmacology of State Administration of Traditional Chinese Medicine, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, PR China
| | - Jin-Zhou Tian
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), PR China.,BUCM Neurology Center, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, PR China
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31
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Zochodne DW. Sensory Neurodegeneration in Diabetes: Beyond Glucotoxicity. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 127:151-80. [PMID: 27133149 DOI: 10.1016/bs.irn.2016.03.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Diabetic polyneuropathy in humans is of gradual, sometimes insidious onset, and is more likely to occur if glucose control is poor. Arguments that the disorder arises chiefly from glucose toxicity however ignore the greater complexity of a unique neurodegenerative disorder. For example, sensory neurons regularly thrive in media with levels of glucose at or exceeding those of poorly controlled diabetic persons. Also, all of the linkages between hyperglycemia and neuropathy develop in the setting of altered insulin availability or sensitivity. Insulin itself is recognized as a potent growth, or trophic factor for adult sensory neurons. Low doses of insulin, insufficient to alter blood glucose levels, reverse features of diabetic neurodegeneration in animal models. Insulin resistance, as occurs in diabetic adipose tissue, liver, and muscle, also develops in sensory neurons, offering a mechanism for neurodegeneration in the setting of normal or elevated insulin levels. Other interventions that "shore up" sensory neurons prevent features of diabetic polyneuropathy from developing despite persistent hyperglycemia. More recently evidence has emerged that a series of subtle molecular changes in sensory neurons can be linked to neurodegeneration including epigenetic changes in the control of gene expression. Understanding the new complexity of sensory neuron degeneration may give rise to therapeutic strategies that have a higher chance of success in the clinical trial arena.
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Affiliation(s)
- D W Zochodne
- Neuroscience and Mental Health Institute and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada.
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32
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Tsuboi K, Mizukami H, Inaba W, Baba M, Yagihashi S. The dipeptidyl peptidase IV inhibitor vildagliptin suppresses development of neuropathy in diabetic rodents: effects on peripheral sensory nerve function, structure and molecular changes. J Neurochem 2016; 136:859-870. [PMID: 26603140 DOI: 10.1111/jnc.13439] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 11/03/2015] [Accepted: 11/04/2015] [Indexed: 01/01/2023]
Abstract
Incretin-related therapy was found to be beneficial for experimental diabetic neuropathy, but its mechanism is obscure. The purpose of this study is to explore the mechanism through which dipeptidyl peptidase IV inhibitor, vildagliptin (VG), influences neuropathy in diabetic rodents. To this end, non-obese type 2 diabetic Goto-Kakizaki rats (GK) and streptozotocin (STZ)-induced diabetic mice were treated with VG orally. Neuropathy was evaluated by nerve conduction velocity (NCV) in both GK and STZ-diabetic mice, whereas calcitonin-gene-related peptide expressions, neuronal cell size of dorsal root ganglion (DRG) and intraepidermal nerve fiber density were examined in GK. DRG from GK and STZ-diabetic mice served for the analyses of GLP-1 and insulin signaling. As results, VG treatment improved glucose intolerance and increased serum insulin and GLP-1 in GK accompanied by the amelioration of delayed NCV and neuronal atrophy, reduced calcitonin-gene-related peptide expressions and intraepidermal nerve fiber density. Diet restriction alone did not significantly influence these measures. Impaired GLP-1 signals such as cAMP response element binding protein, protein kinase B/Akt (PKB/Akt) and S6RP in DRG of GK were restored in VG-treated group, but the effect was equivocal in diet-treated GK. Concurrently, decreased phosphorylation of insulin receptor substrate 2 in GK was corrected by VG treatment. Consistent with the effect on GK, VG treatment improved NCV in diabetic mice without influence on hyperglycemia. DRG of VG-treated diabetic mice were characterized by correction of GLP-1 signals and insulin receptor substrate 2 phosphorylation without effects on insulin receptor β expression. The results suggest close association of neuropathy development with impaired signaling of insulin and GLP-1 in diabetic rodents. Diabetic neurons are resistant to insulin and such insulin resistance may contribute to development of neuropathy. DPP-IV inhibitor, vildagliptin, corrected insulin resistance and improved neuropathy irrespective of blood glucose via augmented action of GLP-1.
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Affiliation(s)
- Kentaro Tsuboi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Hiroki Mizukami
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Wataru Inaba
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Masayuki Baba
- Department of Neurology, Aomori Prefectural Hospital, Aomori, Japan
| | - Soroku Yagihashi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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33
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Li MY, Wang YY, Cao R, Hou XH, Zhang L, Yang RH, Wang F. Dietary fish oil inhibits mechanical allodynia and thermal hyperalgesia in diabetic rats by blocking nuclear factor-κB-mediated inflammatory pathways. J Nutr Biochem 2015; 26:1147-55. [PMID: 26118694 DOI: 10.1016/j.jnutbio.2015.05.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 04/29/2015] [Accepted: 05/08/2015] [Indexed: 01/12/2023]
Abstract
One of the most common complications of early-onset diabetes mellitus is peripheral diabetic neuropathy, which is manifested either by loss of nociception or by allodynia and hyperalgesia. Diabetes mellitus is a common metabolic disease in human beings with characteristic symptoms of hyperglycemia, chronic inflammation and insulin resistance. Dietary fatty acids, especially polyunsaturated fatty acids, have been shown anti-inflammatory role in various experimental conditions. The present study investigated the effects of fish oil supplementation on the inflammation in the dorsal root ganglion (DRG) of streptozotocin (STZ)-induced diabetes rats. The effects of diabetes and fish oil treatment on the allodynia and hyperalgesia were also evaluated. Dietary fish oil effectively attenuated both allodynia and hyperalgesia induce by STZ injection. Along with the behavioral findings, DRG from fish oil-treated diabetic rats displayed a decrease in inflammatory cytokines and the expression of nuclear factor-κB (NF-κB) compared with untreated diabetic rats. Fish oil supplementation also increased the phosphorylation of AKT in DRG of diabetic rats. These results suggested that dietary fish oil-inhibited allodynia and hyperalgesia in diabetic rats may stem from its anti-inflammatory potential by regulating NF-κB and AKT. Fish oil might be useful as an adjuvant therapy for the prevention and treatment of diabetic complications.
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Affiliation(s)
- Meng-Ying Li
- Department of Nutrition and Food Hygiene, School of Public Health, the Fourth Military Medical University, Xi'an 710032, P.R. China
| | - Ya-Yun Wang
- Department of Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an 710032, P.R. China
| | - Rui Cao
- Department of Nutrition and Food Hygiene, School of Public Health, the Fourth Military Medical University, Xi'an 710032, P.R. China
| | - Xiang-Hong Hou
- Department of Nutrition and Food Hygiene, School of Public Health, the Fourth Military Medical University, Xi'an 710032, P.R. China
| | - Lei Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, the Fourth Military Medical University, Xi'an 710032, P.R. China
| | - Rui-Hua Yang
- Department of Nutrition and Food Hygiene, School of Public Health, the Fourth Military Medical University, Xi'an 710032, P.R. China.
| | - Feng Wang
- Department of Nutrition and Food Hygiene, School of Public Health, the Fourth Military Medical University, Xi'an 710032, P.R. China.
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Song J, Kang SM, Kim E, Kim CH, Song HT, Lee JE. Impairment of insulin receptor substrate 1 signaling by insulin resistance inhibits neurite outgrowth and aggravates neuronal cell death. Neuroscience 2015; 301:26-38. [PMID: 26047734 DOI: 10.1016/j.neuroscience.2015.05.072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 05/22/2015] [Accepted: 05/28/2015] [Indexed: 02/02/2023]
Abstract
In the central nervous system (CNS), insulin resistance (I/R) can cause defective neurite outgrowth and neuronal cell death, which can eventually lead to cognitive deficits. Recent research has focused on the relationship between I/R and the cognitive impairment caused by dementia, with the goal of developing treatments for dementia. Insulin signal transduction mediated by insulin receptor substrate (IRS-1) has been thoroughly studied in the CNS of patients with I/R. In the present study, we investigated whether the impairment of IRS-1-mediated insulin signaling contributes to neurite outgrowth and neuronal loss, both in mice fed a high-fat diet and in mouse neuroblastoma (Neuro2A) cells. To investigate the changes caused by the inhibition of IRS-1-mediated insulin signaling in the brain, we performed Cresyl Violet staining and immunochemical analysis. To investigate the changes caused by the inhibition of IRS-1-mediated insulin signaling in neuroblastoma cells, we performed Western blot analysis, reverse transcription-PCR, and immunochemical analysis. We show that the deactivation of IRS-1-mediated insulin signaling can inhibit neuronal outgrowth and aggravate neuronal cell death in the insulin-resistant CNS. Thus, IRS-1-mediated insulin signal transduction may be an important factor in the treatment of cognitive decline induced by I/R.
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Affiliation(s)
- J Song
- Department of Anatomy, Yonsei University College of Medicine, Seoul 120-752, South Korea.
| | - S M Kang
- Department of Anatomy, Yonsei University College of Medicine, Seoul 120-752, South Korea; BK21 Plus Project for Medical Sciences and Brain Research Institute, Yonsei University College of Medicine, Seoul 120-752, South Korea.
| | - E Kim
- Department of Psychiatry, Yonsei University College of Medicine, Seoul 120-752, South Korea.
| | - C-H Kim
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 120-752, South Korea.
| | - H-T Song
- Department of Diagnostic Radiology, Yonsei University College of Medicine, Seoul 120-752, South Korea.
| | - J E Lee
- Department of Anatomy, Yonsei University College of Medicine, Seoul 120-752, South Korea; BK21 Plus Project for Medical Sciences and Brain Research Institute, Yonsei University College of Medicine, Seoul 120-752, South Korea.
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35
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Tsukamoto M, Niimi N, Sango K, Takaku S, Kanazawa Y, Utsunomiya K. Neurotrophic and neuroprotective properties of exendin-4 in adult rat dorsal root ganglion neurons: involvement of insulin and RhoA. Histochem Cell Biol 2015; 144:249-59. [PMID: 26026990 DOI: 10.1007/s00418-015-1333-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2015] [Indexed: 11/26/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is thought to preserve neurons and glia following axonal injury and neurodegenerative disorders. We investigated the neurotrophic and neuroprotective properties of exendin (Ex)-4, a synthetic GLP-1 receptor (GLP-1R) agonist, on adult rat dorsal root ganglion (DRG) neurons and PC12 cells. GLP-1R was predominantly localized on large and small peptidergic neurons in vivo and in vitro, suggesting the involvement of GLP-1 in both the large and small sensory fiber functions. Ex-4 dose-dependently (1 ≤ 10 ≤ 100 nM) promoted neurite outgrowth and neuronal survival at 2 and 7 days in culture, respectively. Treatment with 100 nM Ex-4 restored the reduced neurite outgrowth and viability of DRG neurons caused by the insulin removal from the medium and suppressed the activity of RhoA, an inhibitory regulator for peripheral nerve regeneration, in PC12 cells. Furthermore, these effects were attenuated by co-treatment with phosphatidylinositol-3'-phosphate kinase (PI3K) inhibitor, LY294002. These findings imply that Ex-4 enhances neurite outgrowth and neuronal survival through the activation of PI3K signaling pathway, which negatively regulates RhoA activity. Ex-4 and other GLP-1R agonists may compensate for the reduced insulin effects on neurons, thereby being beneficial for the treatment of diabetic neuropathy.
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Affiliation(s)
- Masami Tsukamoto
- Diabetic Neuropathy Project (Former Laboratory of Peripheral Nerve Pathophysiology), Department of Sensory and Motor Systems, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan
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36
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Petrov D, Pedrós I, Artiach G, Sureda FX, Barroso E, Pallàs M, Casadesús G, Beas-Zarate C, Carro E, Ferrer I, Vazquez-Carrera M, Folch J, Camins A. High-fat diet-induced deregulation of hippocampal insulin signaling and mitochondrial homeostasis deficiences contribute to Alzheimer disease pathology in rodents. Biochim Biophys Acta Mol Basis Dis 2015; 1852:1687-99. [PMID: 26003667 DOI: 10.1016/j.bbadis.2015.05.004] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/09/2015] [Accepted: 05/06/2015] [Indexed: 01/04/2023]
Abstract
Global obesity is a pandemic status, estimated to affect over 2 billion people, that has resulted in an enormous strain on healthcare systems worldwide. The situation is compounded by the fact that apart from the direct costs associated with overweight pathology, obesity presents itself with a number of comorbidities, including an increased risk for the development of neurodegenerative disorders. Alzheimer disease (AD), the main cause of senile dementia, is no exception. Spectacular failure of the pharmaceutical industry to come up with effective AD treatment strategies is forcing the broader scientific community to rethink the underlying molecular mechanisms leading to cognitive decline. To this end, the emphasis is once again placed on the experimental animal models of the disease. In the current study, we have focused on the effects of a high-fat diet (HFD) on hippocampal-dependent memory in C57/Bl6 Wild-type (WT) and APPswe/PS1dE9 (APP/PS1) mice, a well-established mouse model of familial AD. Our results indicate that the continuous HFD administration starting at the time of weaning is sufficient to produce β-amyloid-independent, hippocampal-dependent memory deficits measured by a 2-object novel-object recognition test (NOR) in mice as early as 6months of age. Furthermore, the resulting metabolic syndrome appears to have direct effects on brain insulin regulation and mitochondrial function. We have observed pathological changes related to both the proximal and distal insulin signaling pathway in the brains of HFD-fed WT and APP/PS1 mice. These changes are accompanied by a significantly reduced OXPHOS metabolism, suggesting that mitochondria play an important role in hippocampus-dependent memory formation and retention in both the HFD-treated and AD-like rodents at a relatively young age.
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Affiliation(s)
- Dmitry Petrov
- Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Institut de Biomedicina de la UB (IBUB), Universitat de Barcelona, Barcelona, Spain; Biomedical Research Networking Center in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Ignacio Pedrós
- Unitats de Bioquímica i Farmacologia, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus (Tarragona), Spain; Biomedical Research Networking Center in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Gonzalo Artiach
- Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Institut de Biomedicina de la UB (IBUB), Universitat de Barcelona, Barcelona, Spain; Biomedical Research Networking Center in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Francesc X Sureda
- Unitats de Bioquímica i Farmacologia, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus (Tarragona), Spain; Biomedical Research Networking Center in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Emma Barroso
- Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Institut de Biomedicina de la UB (IBUB), Universitat de Barcelona, Barcelona, Spain; Centros de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Mercè Pallàs
- Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Institut de Biomedicina de la UB (IBUB), Universitat de Barcelona, Barcelona, Spain; Biomedical Research Networking Center in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Gemma Casadesús
- Department of Biological Sciences Kent State University, Kent, OH, USA
| | - Carlos Beas-Zarate
- Laboratorio de Neurobiología Celular y Molecular, División de Neurociencias, CIBO, IMSS, México; Laboratorio de Regeneración y Desarrollo Neural, Instituto de Neurobiología, Departamento de Biología Celular y Molecular, CUCBA, México
| | - Eva Carro
- Neuroscience Group, Instituto de Investigacion Hospital 12 de Octubre, Madrid, Spain
| | - Isidro Ferrer
- Institute of Neuropathology, Bellvitge University Hospital-Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Spain
| | - Manuel Vazquez-Carrera
- Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Institut de Biomedicina de la UB (IBUB), Universitat de Barcelona, Barcelona, Spain; Centros de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Jaume Folch
- Unitats de Bioquímica i Farmacologia, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus (Tarragona), Spain; Biomedical Research Networking Center in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Antoni Camins
- Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Institut de Biomedicina de la UB (IBUB), Universitat de Barcelona, Barcelona, Spain; Biomedical Research Networking Center in Neurodegenerative Diseases (CIBERNED), Madrid, Spain; Universidad Nacional de Loja, Department of Biotechnology, Ecuador.
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O'Brien PD, Hinder LM, Sakowski SA, Feldman EL. ER stress in diabetic peripheral neuropathy: A new therapeutic target. Antioxid Redox Signal 2014; 21:621-33. [PMID: 24382087 DOI: 10.1089/ars.2013.5807] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Diabetes and other diseases that comprise the metabolic syndrome have reached epidemic proportions. Diabetic peripheral neuropathy (DPN) is the most prevalent complication of diabetes, affecting ~50% of diabetic patients. Characterized by chronic pain or loss of sensation, recurrent foot ulcerations, and risk for amputation, DPN is associated with significant morbidity and mortality. Mechanisms underlying DPN pathogenesis are complex and not well understood, and no effective treatments are available. Thus, an improved understanding of DPN pathogenesis is critical for the development of successful therapeutic options. RECENT ADVANCES Recent research implicates endoplasmic reticulum (ER) stress as a novel mechanism in the onset and progression of DPN. ER stress activates the unfolded protein response (UPR), a well-orchestrated signaling cascade responsible for relieving stress and restoring normal ER function. CRITICAL ISSUES During times of extreme or chronic stress, such as that associated with diabetes, the UPR may be insufficient to alleviate ER stress, resulting in apoptosis. Here, we discuss the potential role of ER stress in DPN, as well as evidence demonstrating how ER stress intersects with pathways involved in DPN development and progression. An improved understanding of how ER stress contributes to peripheral nerve dysfunction in diabetes will provide important insight into DPN pathogenesis. FUTURE DIRECTIONS Future studies aimed at gaining the necessary insight into ER stress in DPN pathogenesis will ultimately facilitate the development of novel therapies.
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Dunn TN, Adams SH. Relations between metabolic homeostasis, diet, and peripheral afferent neuron biology. Adv Nutr 2014; 5:386-93. [PMID: 25022988 PMCID: PMC4085187 DOI: 10.3945/an.113.005439] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
It is well established that food intake behavior and energy balance are regulated by crosstalk between peripheral organ systems and the central nervous system (CNS), for instance, through the actions of peripherally derived leptin on hindbrain and hypothalamic loci. Diet- or obesity-associated disturbances in metabolic and hormonal signals to the CNS can perturb metabolic homeostasis bodywide. Although interrelations between metabolic status and diet with CNS biology are well characterized, afferent networks (those sending information to the CNS from the periphery) have received far less attention. It is increasingly appreciated that afferent neurons in adipose tissue, the intestines, liver, and other tissues are important controllers of energy balance and feeding behavior. Disruption in their signaling may have consequences for cardiovascular, pancreatic, adipose, and immune function. This review discusses the diverse ways that afferent neurons participate in metabolic homeostasis and highlights how changes in their function associate with dysmetabolic states, such as obesity and insulin resistance.
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Affiliation(s)
- Tamara N. Dunn
- Graduate Group in Nutritional Biology and Department of Nutrition, University of California, Davis, CA; and
| | - Sean H. Adams
- Graduate Group in Nutritional Biology and Department of Nutrition, University of California, Davis, CA; and,Obesity and Metabolism Research Unit, USDA–Agricultural Research Service Western Human Nutrition Research Center, Davis, CA,To whom correspondence should be addressed. E-mail:
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Grote CW, Ryals JM, Wright DE. In vivo peripheral nervous system insulin signaling. J Peripher Nerv Syst 2014; 18:209-19. [PMID: 24028189 DOI: 10.1111/jns5.12033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/07/2013] [Accepted: 07/24/2013] [Indexed: 01/06/2023]
Abstract
Alterations in peripheral nervous system (PNS) insulin support may contribute to diabetic neuropathy (DN); yet, PNS insulin signaling is not fully defined. Here, we investigated in vivo insulin signaling in the PNS and compared the insulin responsiveness to that of muscle, liver, and adipose. Non-diabetic mice were administered increasing doses of insulin to define a dose-response relationship between insulin and Akt activation in the dorsal root ganglion (DRG) and sciatic nerve. Resulting EC50 doses were used to characterize the PNS insulin signaling time course and make comparisons between insulin signaling in the PNS and other peripheral tissues (i.e., muscle, liver, and adipose). The results demonstrate that the PNS is responsive to insulin and that differences in insulin signaling pathway activation exist between PNS compartments. At a therapeutically relevant dose, Akt was activated in the muscle, liver, and adipose at 30 min, correlating with the changes in blood glucose levels. Interestingly, the sciatic nerve showed a similar signaling profile as insulin-sensitive tissues; however, there was not a comparable activation in the DRG or spinal cord. These results present new evidence regarding PNS insulin signaling pathways in vivo and provide a baseline for studies investigating the contribution of disrupted PNS insulin signaling to DN pathogenesis.
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Affiliation(s)
- Caleb W Grote
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
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The adjuvant effect of hypertension upon diabetic peripheral neuropathy in experimental type 2 diabetes. Neurobiol Dis 2013; 62:18-30. [PMID: 23938761 DOI: 10.1016/j.nbd.2013.07.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 07/17/2013] [Accepted: 07/29/2013] [Indexed: 01/30/2023] Open
Abstract
Type 2 diabetes (DM) is the most common cause of peripheral neuropathy in the Western world. A comorbidity, hypertension, has been speculated to contribute to initiation or worsening of diabetic peripheral neuropathy. We studied adult rat models using genetic strains with DM (Zucker Diabetic Fat rats)±hypertension (HTN (ZSF-1 rats)) to investigate the relative contributions of DM and HTN and the potential for additive effects of HTN upon existing DM for the development of peripheral neuropathy. Long duration sensorimotor behavioral and electrophysiological testing was complemented by histological and molecular methods. Only DM led to tactile and thermal hyperalgesia and affected motor nerve electrophysiology. Although DM led to marked loss of sensory amplitudes and to sensory conduction slowing, a mild additive effect from HTN contributed after 6months of DM with worsening of slowing of sensory nerve conduction velocities, but without effect upon sensory amplitudes. At the sensory dominant sural nerve, mild (<10%) but greater degrees of myelin thinning were noted with DM and HTN combined, suggesting a mild additive effect. Matrix metalloproteinase (MMP) expression was increased only at the sural nerve in the presence of HTN with co-localization to Schwann cells and myelin. The effects of DM and HTN upon peripheral nerve are dissimilar, with HTN contributing to MMP upregulation at the sites of myelin thinning at sensory nerve fibers, potentially worsening comorbid DM. Together, our results indicate that HTN has a mild additive contribution to diabetic peripheral neuropathy at sensory peripheral nerve fibers manifesting with the loss of myelin thickness.
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Grote CW, Groover AL, Ryals JM, Geiger PC, Feldman EL, Wright DE. Peripheral nervous system insulin resistance in ob/ob mice. Acta Neuropathol Commun 2013; 1:15. [PMID: 24252636 PMCID: PMC3893412 DOI: 10.1186/2051-5960-1-15] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 04/19/2013] [Indexed: 12/20/2022] Open
Abstract
Background A reduction in peripheral nervous system (PNS) insulin signaling is a proposed mechanism that may contribute to sensory neuron dysfunction and diabetic neuropathy. Neuronal insulin resistance is associated with several neurological disorders and recent evidence has indicated that dorsal root ganglion (DRG) neurons in primary culture display altered insulin signaling, yet in vivo results are lacking. Here, experiments were performed to test the hypothesis that the PNS of insulin-resistant mice displays altered insulin signal transduction in vivo. For these studies, nondiabetic control and type 2 diabetic ob/ob mice were challenged with an intrathecal injection of insulin or insulin-like growth factor 1 (IGF-1) and downstream signaling was evaluated in the DRG and sciatic nerve using Western blot analysis. Results The results indicate that insulin signaling abnormalities documented in other “insulin sensitive” tissues (i.e. muscle, fat, liver) of ob/ob mice are also present in the PNS. A robust increase in Akt activation was observed with insulin and IGF-1 stimulation in nondiabetic mice in both the sciatic nerve and DRG; however this response was blunted in both tissues from ob/ob mice. The results also suggest that upregulated JNK activation and reduced insulin receptor expression could be contributory mechanisms of PNS insulin resistance within sensory neurons. Conclusions These findings contribute to the growing body of evidence that alterations in insulin signaling occur in the PNS and may be a key factor in the pathogenesis of diabetic neuropathy.
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Abstract
PURPOSE OF REVIEW To compare and contrast the evidence for the effect of glucose control on the prevention of neuropathy in type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). RECENT FINDINGS In T1DM, multiple clinical trials have demonstrated a large benefit from enhanced glucose control, whereas the benefit in T2DM is much more modest. Epidemiologic and laboratory evidence exists to support factors other than hyperglycemia in the development of neuropathy including obesity, hypertension, dyslipidemia, inflammation, and insulin resistance. SUMMARY T1DM neuropathy and T2DM neuropathy are fundamentally different. In T1DM, glucose control has a large effect on the prevention of neuropathy; therefore, future efforts should continue to concentrate on this avenue of treatment. In contrast, in T2DM, glucose control has a small effect on the prevention of neuropathy; as a result, more research is needed to define the underlying mechanisms for the development of neuropathy. Understanding these mechanisms may lead to novel therapeutic approaches to prevent or treat diabetic neuropathy.
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Huang CH, Chen MF, Chung HH, Cheng JT. Antihyperglycemic effect of syringaldehyde in streptozotocin-induced diabetic rats. JOURNAL OF NATURAL PRODUCTS 2012; 75:1465-8. [PMID: 22880723 DOI: 10.1021/np3003723] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The antihyperglycemic effect of syringaldehyde (1), purified from the stems of Hibiscus taiwanensis, was investigated in streptozotocin-induced diabetic rats (STZ-diabetic rats) showing type-1 like diabetes mellitus. Bolus intravenous injection of 1 showed antihyperglycemic activity in a dose-dependent manner in STZ-diabetic rats. An effective dose of 7.2 mg/kg of 1 attenuated significantly the increase of plasma glucose induced by an intravenous glucose challenge test in normal rats. A glucose uptake test showed that 1 exhibits an increase of glucose uptake activity in a concentration-related manner. Moreover, an effect by 1 was shown for insulin sensitivity in STZ-diabetic rats. The compound was found to increase insulin sensitivity in STZ-diabetic rats. These results suggest that syringaldehyde (1) can increase glucose utilization and insulin sensitivity to lower plasma glucose in diabetic rats.
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Affiliation(s)
- Chia-Hsin Huang
- Agricultural Research Institute, Council of Agriculture Executive, Taichung, Taiwan 40512
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Chirivella L, Cano-Jaimez M, Pérez-Sánchez F, Herraez L, Carretero J, Fariñas I, Burks DJ, Kirstein M. IRS2 signalling is required for the development of a subset of sensory spinal neurons. Eur J Neurosci 2012; 35:341-52. [PMID: 22288475 DOI: 10.1111/j.1460-9568.2011.07959.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Insulin and insulin-like growth factor-I play important roles in the development and maintenance of neurons and glial cells of the nervous system. Both factors activate tyrosine kinase receptors, which signal through adapter proteins of the insulin receptor substrate (IRS) family. Although insulin and insulin-like growth factor-I receptors are expressed in dorsal root ganglia (DRG), the function of IRS-mediated signalling in these structures has not been studied. Here we address the role of IRS2-mediated signalling in murine DRG. Studies in cultured DRG neurons from different embryonic stages indicated that a subset of nerve growth factor-responsive neurons is also dependent on insulin for survival at very early time points. Consistent with this, increased apoptosis during gangliogenesis resulted in a partial loss of trkA-positive neurons in DRG of Irs2 mutant embryos. Analyses in adult Irs2(-/-) mice revealed that unmyelinated fibre afferents, which express calcitonin gene-related peptide/substance P and isolectin B4, as well as some myelinated afferents to the skin were affected by the mutation. The diminished innervation of glabrous skin in adult Irs2(-/-) mice correlated with longer paw withdrawal latencies in the hot-plate assay. Collectively, these findings indicate that IRS2 signalling is required for the proper development of spinal sensory neurons involved in the perception of pain.
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Affiliation(s)
- Laura Chirivella
- Departamento de Biología Celular and Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas, Universidad de Valencia, Doctor Moliner 50, 46100 Burjassot, Spain
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Kim B, Feldman EL. Insulin resistance in the nervous system. Trends Endocrinol Metab 2012; 23:133-41. [PMID: 22245457 PMCID: PMC3392648 DOI: 10.1016/j.tem.2011.12.004] [Citation(s) in RCA: 198] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 12/11/2011] [Accepted: 12/13/2011] [Indexed: 12/15/2022]
Abstract
Metabolic syndrome is a cluster of cardiovascular risk factors including obesity, diabetes and dyslipidemia. Insulin resistance (IR) is at the core of metabolic syndrome. In adipose tissue and muscle, IR results in decreased insulin signaling, primarily affecting downstream phosphatidylinositol 3-kinase (PI3K)/Akt signaling. It was recently proposed that neurons can develop hyperinsulinemia-induced IR, which in turn results in injury to the peripheral and central nervous systems and is probably pathogenic in common neurological disorders such as diabetic neuropathy and Alzheimer's disease (AD). This review presents evidence indicating that, similarly to insulin-dependent metabolically active tissues such as fat and muscle, neurons also develop IR and thus cannot respond to the neurotrophic properties of insulin, resulting in neuronal injury, subsequent dysfunction and disease states.
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Affiliation(s)
- Bhumsoo Kim
- University of Michigan, Department of Neurology, Ann Arbor, MI 48109, USA.
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Urban MJ, Dobrowsky RT, Blagg BSJ. Heat shock response and insulin-associated neurodegeneration. Trends Pharmacol Sci 2011; 33:129-37. [PMID: 22172248 DOI: 10.1016/j.tips.2011.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 10/24/2011] [Accepted: 11/01/2011] [Indexed: 02/07/2023]
Abstract
Dysfunctional insulin and insulin-like growth factor-I (IGF-I) signaling contributes to the pathological progression of diabetes, diabetic peripheral neuropathy (DPN), Alzheimer's (AD), Parkinson's (PD) and Huntington's diseases (HD). Despite their prevalence, there are limited therapeutic options available for the treatment of these neurodegenerative disorders. Therefore, establishing a link between insulin/IGF-I and the pathoetiology of these diseases may provide alternative approaches toward their management. Many of the heat shock proteins (Hsps) are well-known molecular chaperones that solubilize and clear damaged proteins and protein aggregates. Recent studies suggest that modulating Hsps may represent a promising therapeutic avenue for improving insulin and IGF-I signaling. Pharmacological induction of the heat shock response (HSR) may intersect with insulin/IGF-I signaling to improve aspects of neurodegenerative phenotypes. Herein, we review the intersection between Hsps and the insulin/IGF systems under normal and pathological conditions. The discussion will emphasize the potential of non-toxic HSR inducers as viable therapeutic agents.
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Affiliation(s)
- Michael J Urban
- Neuroscience Graduate Program, The University of Kansas, Lawrence, KS 66045, USA
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