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Ferreira DT, Shen BQ, Mwirigi JM, Shiers S, Sankaranarayanan I, Kotamarti M, Inturi NN, Mazhar K, Ubogu EE, Thomas G, Lalli T, Wukich D, Price TJ. Deciphering the molecular landscape of human peripheral nerves: implications for diabetic peripheral neuropathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.15.599167. [PMID: 38915676 PMCID: PMC11195245 DOI: 10.1101/2024.06.15.599167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Diabetic peripheral neuropathy (DPN) is a prevalent complication of diabetes mellitus that is caused by metabolic toxicity to peripheral axons. We aimed to gain deep mechanistic insight into the disease process using bulk and spatial RNA sequencing on tibial and sural nerves recovered from lower leg amputations in a mostly diabetic population. First, our approach comparing mixed sensory and motor tibial and purely sensory sural nerves shows key pathway differences in affected nerves, with distinct immunological features observed in sural nerves. Second, spatial transcriptomics analysis of sural nerves reveals substantial shifts in endothelial and immune cell types associated with severe axonal loss. We also find clear evidence of neuronal gene transcript changes, like PRPH, in nerves with axonal loss suggesting perturbed RNA transport into distal sensory axons. This motivated further investigation into neuronal mRNA localization in peripheral nerve axons generating clear evidence of robust localization of mRNAs such as SCN9A and TRPV1 in human sensory axons. Our work gives new insight into the altered cellular and transcriptomic profiles in human nerves in DPN and highlights the importance of sensory axon mRNA transport as an unappreciated potential contributor to peripheral nerve degeneration.
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Affiliation(s)
- Diana Tavares Ferreira
- Department of Neuroscience and Center for Advanced Pain Studies; University of Texas at Dallas, Richardson, TX, USA
| | - Breanna Q Shen
- Department of Neuroscience and Center for Advanced Pain Studies; University of Texas at Dallas, Richardson, TX, USA
| | - Juliet M Mwirigi
- Department of Neuroscience and Center for Advanced Pain Studies; University of Texas at Dallas, Richardson, TX, USA
| | - Stephanie Shiers
- Department of Neuroscience and Center for Advanced Pain Studies; University of Texas at Dallas, Richardson, TX, USA
| | - Ishwarya Sankaranarayanan
- Department of Neuroscience and Center for Advanced Pain Studies; University of Texas at Dallas, Richardson, TX, USA
| | - Miriam Kotamarti
- Department of Neuroscience and Center for Advanced Pain Studies; University of Texas at Dallas, Richardson, TX, USA
| | - Nikhil N Inturi
- Department of Neuroscience and Center for Advanced Pain Studies; University of Texas at Dallas, Richardson, TX, USA
| | - Khadijah Mazhar
- Department of Neuroscience and Center for Advanced Pain Studies; University of Texas at Dallas, Richardson, TX, USA
| | - Eroboghene E Ubogu
- Department of Neurology, Division of Neuromuscular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Geneva Thomas
- Department of Orthopedic Surgery, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Trapper Lalli
- Department of Orthopedic Surgery, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Dane Wukich
- Department of Orthopedic Surgery, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Theodore J Price
- Department of Neuroscience and Center for Advanced Pain Studies; University of Texas at Dallas, Richardson, TX, USA
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2
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Piątkowska-Chmiel I, Gawrońska-Grzywacz M, Popiołek Ł, Herbet M, Dudka J. The novel adamantane derivatives as potential mediators of inflammation and neural plasticity in diabetes mice with cognitive impairment. Sci Rep 2022; 12:6708. [PMID: 35468904 PMCID: PMC9035983 DOI: 10.1038/s41598-022-10187-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 03/14/2022] [Indexed: 12/12/2022] Open
Abstract
Diabetes is a chronic disease leading to memory difficulties and deterioration of learning abilities. The previous studies showed that modulation of inflammatory pathways in the diabetic brain may reduce dysfunction or cell death in brain areas which are important for control of cognitive function. In the present study, we investigated the neuroprotective actions of newly synthesized adamantane derivatives on diabetes-induced cognitive impairment in mice. Our study relied on the fact that both vildagliptin and saxagliptin belong to DPP4 inhibitors and, contain adamantanyl group. Efficacy of tested compounds at reversing diabetes-induced different types of memory impairment was evaluated with the use of selected behavioural tests. The following neuroinflammatory indicators were also analyzed: neuroinflammatory indicators and the expression of genes involved in the inflammatory response of brain (Cav1, Bdnf). Our study demonstrated that new adamantane derivatives, similarly to DPP4 inhibitors, can restrict diabetes-induced cognitive deficits. We demonstrated that the overexpression of GLP-1-glucagon-like peptide as well as Bdnf, Cav1 genes translate into central blockade of pro-inflammatory synthesis of cytokines and significantly improvement on memory performance in diabetes mice. Newly synthesized adamantane derivatives might have important roles in prevention and treatment of cognitive impairment by inflammatory events in patients with diabetes or related diseases.
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Affiliation(s)
- Iwona Piątkowska-Chmiel
- Chair and Department of Toxicology, Faculty of Pharmacy, Medical University of Lublin, 8b Jaczewskiego Street, 20-090, Lublin, Poland.
| | - Monika Gawrońska-Grzywacz
- Chair and Department of Toxicology, Faculty of Pharmacy, Medical University of Lublin, 8b Jaczewskiego Street, 20-090, Lublin, Poland
| | - Łukasz Popiołek
- Chair and Department of Organic Chemistry, Faculty of Pharmacy, Medical University of Lublin, 4A Chodźki Street, 20-093, Lublin, Poland
| | - Mariola Herbet
- Chair and Department of Toxicology, Faculty of Pharmacy, Medical University of Lublin, 8b Jaczewskiego Street, 20-090, Lublin, Poland
| | - Jarosław Dudka
- Chair and Department of Toxicology, Faculty of Pharmacy, Medical University of Lublin, 8b Jaczewskiego Street, 20-090, Lublin, Poland
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3
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de Oliveira AA, Mendoza VO, Rastogi S, Nunes KP. New insights into the role and therapeutic potential of HSP70 in diabetes. Pharmacol Res 2022; 178:106173. [PMID: 35278625 DOI: 10.1016/j.phrs.2022.106173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/06/2022] [Accepted: 03/07/2022] [Indexed: 10/18/2022]
Abstract
Emerging evidence indicates that HSP70 represents a key mechanism in the pathophysiology of β-cell dysfunction, insulin resistance, and various diabetic complications, including micro- and macro-vascular alterations, as well as impaired hemostasis. Hyperglycemia, a hallmark of both types of diabetes, increases the circulating levels of HSP70 (eHSP70), but there is still divergence about whether diabetes up- or down-regulates the intracellular fraction of this protein (iHSP70). Here, we consider that iHSP70 levels reduce in diabetic arterial structures and that the vascular system is in direct contact with all other systems in the body suggesting that a systemic response might also be happening for iHSP70, which is characterized by decreased levels of HSP70 in the vasculature. Furthermore, although many pathways have been proposed to explain HSP70's functions in diabetes, and organs/tissues/cells-specific variations occur, the membrane-bound receptor of the innate immune system, Toll-like receptor 4, and its downstream signal transduction pathways appear to be a constant, not only when we explore the actions of eHSP70, but also when we assess the contributions of iHSP70. In this review, we focus on discussing the multiple roles of HSP70 across organs/tissues/cells affected by hyperglycemia to further explore the possibility of targeting this protein with pharmacological and non-pharmacological approaches in the context of diabetes.
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Affiliation(s)
- Amanda Almeida de Oliveira
- Laboratory of Vascular Biology, Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, United States
| | - Valentina Ochoa Mendoza
- Laboratory of Vascular Biology, Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, United States
| | - Swasti Rastogi
- Laboratory of Vascular Biology, Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, United States
| | - Kenia Pedrosa Nunes
- Laboratory of Vascular Biology, Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, United States.
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4
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Caveolin-1, a novel player in cognitive decline. Neurosci Biobehav Rev 2021; 129:95-106. [PMID: 34237390 DOI: 10.1016/j.neubiorev.2021.06.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 06/29/2021] [Indexed: 12/12/2022]
Abstract
Cognitive decline (CD), which related to vascular dementia, Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis and diabetes mellitus, is a growing health concern that has a great impact on the patients' quality of life. Although extensive efforts, the mechanisms of CD are still far from being clarified, not to mention the effective treatment and prevention strategies. Caveolin-1 (Cav-1), a trans-membrane protein, is a major component of the caveolae structure and scaffolding proteins. Recently, ample evidence depicts a strong correlation between Cav-1 and CD, however, the specific role of Cav-1 in CD has not been clearly examined and how they might be connected have yet to be identified. This review seeks to provide a comprehensive overview about how Cav-1 modulates pathogeneses of CD-associated diseases. In summary, Cav-1 can promote structural and functional plasticity of neurons, improve neurogenesis, relieve mitochondrial dysfunction, inhibit inflammation and suppress oxidative stress, which have shed light on the idea that Cav-1 may be an efficacious therapeutic target to treat CD.
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5
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Silva-Alves KS, Ferreira-da-Silva FW, Coelho-de-Souza AN, Leal-Cardoso JH. Essential Oil of Croton zehntneri Prevents Conduction Alterations Produced by Diabetes Mellitus on Vagus Nerve. PLANTS 2021; 10:plants10050893. [PMID: 33925228 PMCID: PMC8146017 DOI: 10.3390/plants10050893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 12/30/2022]
Abstract
Autonomic diabetic neuropathy (ADN) is a complication of diabetes mellitus (DM), to which there is no specific treatment. In this study, the efficacy of the essential oil of Croton zehntneri (EOCz) in preventing ADN was evaluated in the rat vagus nerve. For the two fastest conducting myelinated types of axons of the vagus nerve, the conduction velocities and rheobase decreased, whilst the duration of the components of the compound action potential of these fibers increased. EOCz completely prevented these DM-induced alterations of the vagus nerve. Unmyelinated fibers were not affected. In conclusion, this investigation demonstrated that EOCz is a potential therapeutic agent for the treatment of ADN.
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Affiliation(s)
- Kerly Shamyra Silva-Alves
- Laboratory of Electrophysiology, Superior Institute of Biomedical Science, State University of Ceará, Fortaleza CEP 60.740-000, Brazil; (K.S.S.-A.); (F.W.F.-d.-S.); (A.N.C.-d.-S.)
| | - Francisco Walber Ferreira-da-Silva
- Laboratory of Electrophysiology, Superior Institute of Biomedical Science, State University of Ceará, Fortaleza CEP 60.740-000, Brazil; (K.S.S.-A.); (F.W.F.-d.-S.); (A.N.C.-d.-S.)
- Center of Exact Sciences and Technology, State University of Vale do Acaraú, Sobral CEP 62.042-030, Brazil
| | - Andrelina Noronha Coelho-de-Souza
- Laboratory of Electrophysiology, Superior Institute of Biomedical Science, State University of Ceará, Fortaleza CEP 60.740-000, Brazil; (K.S.S.-A.); (F.W.F.-d.-S.); (A.N.C.-d.-S.)
- Laboratory of Experimental Physiology, Superior Institute of Biomedical Science, State University of Ceará, Fortaleza CEP 60.740-000, Brazil
| | - José Henrique Leal-Cardoso
- Laboratory of Electrophysiology, Superior Institute of Biomedical Science, State University of Ceará, Fortaleza CEP 60.740-000, Brazil; (K.S.S.-A.); (F.W.F.-d.-S.); (A.N.C.-d.-S.)
- Correspondence: ; Tel.: +55-85-3101-9814
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6
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Kruglikov I. Acoustic Waves in Axonal Membrane and Caveolins are the New Targets for Pain Treatment with High Frequency Ultrasound. J Pain Res 2020; 13:2791-2798. [PMID: 33173328 PMCID: PMC7646452 DOI: 10.2147/jpr.s281468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/14/2020] [Indexed: 12/18/2022] Open
Abstract
Reciprocal interaction between electrical and mechanical waves observed in axonal membrane during its excitation leads to a paradigm shift in pain research making the uncoupling of electro-mechanical signals an interesting target in pain treatment. This uncoupling can be realized either through direct disturbance of the mechanical surface waves in axonal membrane or through shifting of the thermodynamic state of this membrane far from its phase transition point. Both effects can be effectively realized through application of the very high frequency ultrasound waves. Additional target for application of ultrasound in pain treatment is the caveolin-1, which is abundantly present in Schwann cells as well as in the non-axonal tissues. Both targets demonstrate frequency-dependent reactions, thus making a very high frequency ultrasound a promising treatment modality in pain treatment.
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Affiliation(s)
- Ilja Kruglikov
- Scientific Department, Wellcomet GmbH, Karlsruhe, Germany
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7
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Xi C, Zhang Y, Yan M, Lv Q, Lu H, Zhou J, Wang Y, Li J. Exogenous neuritin treatment improves survivability and functions of Schwann cells with improved outgrowth of neurons in rat diabetic neuropathy. J Cell Mol Med 2020; 24:10166-10176. [PMID: 32667138 PMCID: PMC7520300 DOI: 10.1111/jcmm.15627] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 06/16/2020] [Accepted: 06/23/2020] [Indexed: 11/30/2022] Open
Abstract
Pathogenesis and treatment for diabetic neuropathy are still complex. A deficit of neurotrophic factors affecting Schwann cells is a very important cause of diabetic neuropathy. Neuritin is a newly discovered potential neurotrophic factor. In this study, we explored the effect of exogenous neuritin on survivability and functions of diabetic Schwann cells of rats with experimental diabetic neuropathy. Diabetic neuropathy was induced in rats. 12‐week diabetic rats contrasted with non‐diabetic normal rats had decreased levels of serum neuritin and slowed nerve conduction velocities (NCVs). Schwann cells isolated from these diabetic rats and cultured in high glucose showed reduced cell neuritin mRNA and protein and supernatant neuritin protein, increased apoptosis rates, increased caspase‐3 activities and progressively reduced viability. In contrast, exogenous neuritin treatment reduced apoptosis and improved viability, with elevated Bcl‐2 levels (not Bax) and decreased caspase‐3 activities. Co‐cultured with diabetic Schwann cells pre‐treated with exogenous neuritin in high glucose media, and diabetic DRG neurons showed lessened decreased neurite outgrowth and supernatant NGF concentration occurring in co‐culture of diabetic cells. Exogenous neuritin treatment ameliorated survivability and functions of diabetic Schwann cells of rats with diabetic neuropathy. Our study may provide a new mechanism and potential treatment for diabetic neuropathy.
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Affiliation(s)
- Chunhong Xi
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yingduan Zhang
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Mei Yan
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Qing Lv
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Huan Lu
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jun Zhou
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yucheng Wang
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jianbo Li
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.,Diabetic Neuropathy Study Group of Chinese Diabetes Society, Beijing, China
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8
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Role of Caveolin-1 in Diabetes and Its Complications. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:9761539. [PMID: 32082483 PMCID: PMC7007939 DOI: 10.1155/2020/9761539] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/10/2019] [Accepted: 12/26/2019] [Indexed: 12/25/2022]
Abstract
It is estimated that in 2017 there were 451 million people with diabetes worldwide. These figures are expected to increase to 693 million by 2045; thus, innovative preventative programs and treatments are a necessity to fight this escalating pandemic disorder. Caveolin-1 (CAV1), an integral membrane protein, is the principal component of caveolae in membranes and is involved in multiple cellular functions such as endocytosis, cholesterol homeostasis, signal transduction, and mechanoprotection. Previous studies demonstrated that CAV1 is critical for insulin receptor-mediated signaling, insulin secretion, and potentially the development of insulin resistance. Here, we summarize the recent progress on the role of CAV1 in diabetes and diabetic complications.
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9
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Liang M, Cai X, Tang Y, Yang X, Fang J, Li J, Zhang S, Zhou Q. Diffusion tensor imaging of white matter in patients with prediabetes by trace‐based spatial statistics. J Magn Reson Imaging 2018; 49:1105-1112. [PMID: 30302864 DOI: 10.1002/jmri.26290] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/22/2018] [Accepted: 07/23/2018] [Indexed: 12/14/2022] Open
Affiliation(s)
- Minjie Liang
- Medical Imaging Center, First Affiliated HospitalJinan University Guangzhou Guangdong China
| | - Xiangyi Cai
- Medical Imaging Center, First Affiliated HospitalJinan University Guangzhou Guangdong China
| | - Yi Tang
- Department of Medical technologyThe Second Traditional Chinese Medicine Hospital of Guangdong Province Guangzhou Guangdong China
| | - Xiao‐ling Yang
- Medical Imaging Center, First Affiliated HospitalJinan University Guangzhou Guangdong China
| | - Jin Fang
- Medical Imaging Center, First Affiliated HospitalJinan University Guangzhou Guangdong China
| | - Jie Li
- Medical Imaging Center, First Affiliated HospitalJinan University Guangzhou Guangdong China
- Medical Imaging CenterAffiliated hospital of Hangzhou Normal University Hangzhou Zhejiang China
| | - ShuiHua Zhang
- Medical Imaging Center, First Affiliated HospitalJinan University Guangzhou Guangdong China
| | - Quan Zhou
- Medical Imaging Center, First Affiliated HospitalJinan University Guangzhou Guangdong China
- Medical Imaging CenterThird Affiliated Hospital, Southern Medical University Guangzhou Guangdong China
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10
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Wu J, Zhou SL, Pi LH, Shi XJ, Ma LR, Chen Z, Qu ML, Li X, Nie SD, Liao DF, Pei JJ, Wang S. High glucose induces formation of tau hyperphosphorylation via Cav-1-mTOR pathway: A potential molecular mechanism for diabetes-induced cognitive dysfunction. Oncotarget 2018; 8:40843-40856. [PMID: 28489581 PMCID: PMC5522306 DOI: 10.18632/oncotarget.17257] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 04/07/2017] [Indexed: 12/31/2022] Open
Abstract
The abnormally hyperphosphorylated tau is thought to be implicated in diabetes-associated cognitive deficits. The role of mammalian target of rapamycin (mTOR) / S6 kinase (S6K) signalling in the formation of tau hyperphosphorylation has been previously studied. Caveolin-1 (Cav-1), the essential structure protein of caveolae, promotes neuronal survival and growth, and inhibits glucose metabolism. In this study, we aimed to investigate the role of Cav-1 in the formation of tau hyperphosphorylation under chronic hyperglycemic condition (HGC). Diabetic rats were induced by streptozotocin (STZ). Primary hippocampal neurons with or without molecular intervention such as the transient over-expression or knock-down were subjected to HGC. The obtained experimental samples were analyzed by real time quantitative RT-PCR, Western blot, immunofluorescence or immunohistochemisty. We found: 1) that a chronic HGC directly decreases Cav-1 expression, increases tau phosphorylation and activates mTOR/S6K signalling in the brain neurons of diabetic rats, 2) that overexpression of Cav-1 attenuates tau hyperphosphorylation induced by chronic HGC in primary hippocampal neurons, whereas down-regulation of Cav-1 using Cav-1 siRNA dramatically worsens tau hyperphosphorylation via mTOR/S6K signalling pathway, and 3) that the down-regulation of Cav-1 induced by HGC is independent of mTOR signalling. Our results suggest that tau hyperphosphorylation and the sustained over-activated mTOR signalling under hyperglycemia may be due to the suppression of Cav-1. Therefore, Cav-1 is a potential therapeutic target for diabetes-induced cognitive dysfunction.
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Affiliation(s)
- Jing Wu
- Department of Endocrinology, Xiang-Ya Hospital, Central South University, Changsha, China
| | - Shan-Lei Zhou
- Department of Endocrinology, Xiang-Ya Hospital, Central South University, Changsha, China
| | - Lin-Hua Pi
- Department of Endocrinology, Xiang-Ya Hospital, Central South University, Changsha, China
| | - Xia-Jie Shi
- Department of Endocrinology, Xiang-Ya Hospital, Central South University, Changsha, China
| | - Ling-Ran Ma
- Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, China
| | - Zi Chen
- Department of Endocrinology, Xiang-Ya Hospital, Central South University, Changsha, China
| | - Min-Li Qu
- Department of Endocrinology, Xiang-Ya Hospital, Central South University, Changsha, China
| | - Xin Li
- Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, China
| | - Sheng-Dan Nie
- Institute of Clinical Medicine, People's Hospital of Hunan province, The First Affiliated Hospital of Hunan Normal University, Changsha, China
| | - Duan-Fang Liao
- Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China
| | - Jin-Jing Pei
- KI-Alzheimer's Disease Research Center, Karolinska Institutet, Novum, Stockholm, Sweden.,Department of Neurology, Xuan Wu Hospital, Capital Medical University, China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, China
| | - Shan Wang
- Department of Endocrinology, Xiang-Ya Hospital, Central South University, Changsha, China.,Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, China
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11
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Prabodha LBL, Sirisena ND, Dissanayake VHW. Susceptible and Prognostic Genetic Factors Associated with Diabetic Peripheral Neuropathy: A Comprehensive Literature Review. Int J Endocrinol 2018; 2018:8641942. [PMID: 29736170 PMCID: PMC5875044 DOI: 10.1155/2018/8641942] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/29/2018] [Indexed: 02/07/2023] Open
Abstract
Type 2 diabetes mellitus (T2D) is a disorder of glucose metabolism. It is a complex process involving the regulation of insulin secretion, insulin sensitivity, gluconeogenesis, and glucose uptake at the cellular level. Diabetic peripheral neuropathy (DPN) is one of the debilitating complications that is present in approximately 50% of diabetic patients. It is the primary cause of diabetes-related hospital admissions and nontraumatic foot amputations. The pathogenesis of diabetic neuropathy is a complex process that involves hyperglycemia-induced oxidative stress and altered polyol metabolism that changes the nerve microvasculature, altered growth factor support, and deregulated lipid metabolism. Recent literature has reported that there are several heterogeneous groups of susceptible genetic loci which clearly contribute to the development of DPN. Several studies have reported that some patients with prediabetes develop neuropathic complications, whereas others demonstrated little evidence of neuropathy even after long-standing diabetes. There is emerging evidence that genetic factors may contribute to the development of DPN. This paper aims to provide an up-to-date review of the susceptible and prognostic genetic factors associated with DPN. An extensive survey of the scientific literature published in PubMed using the search terms "Diabetic peripheral neuropathy/genetics" and "genome-wide association study" was carried out, and the most recent and relevant literature were included in this review.
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Affiliation(s)
- L. B. L. Prabodha
- Human Genetics Unit, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - N. D. Sirisena
- Human Genetics Unit, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - V. H. W. Dissanayake
- Human Genetics Unit, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
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12
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Gonçalves NP, Vægter CB, Andersen H, Østergaard L, Calcutt NA, Jensen TS. Schwann cell interactions with axons and microvessels in diabetic neuropathy. Nat Rev Neurol 2017; 13:135-147. [PMID: 28134254 DOI: 10.1038/nrneurol.2016.201] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The prevalence of diabetes worldwide is at pandemic levels, with the number of patients increasing by 5% annually. The most common complication of diabetes is peripheral neuropathy, which has a prevalence as high as 50% and is characterized by damage to neurons, Schwann cells and blood vessels within the nerve. The pathogenic mechanisms of diabetic neuropathy remain poorly understood, impeding the development of targeted therapies to treat nerve degeneration and its most disruptive consequences of sensory loss and neuropathic pain. Involvement of Schwann cells has long been proposed, and new research techniques are beginning to unravel a complex interplay between these cells, axons and microvessels that is compromised during the development of diabetic neuropathy. In this Review, we discuss the evolving concept of Schwannopathy as an integral factor in the pathogenesis of diabetic neuropathy, and how disruption of the interactions between Schwann cells, axons and microvessels contribute to the disease.
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Affiliation(s)
- Nádia P Gonçalves
- The International Diabetic Neuropathy Consortium (IDNC), Aarhus University, Nørrebrogade, 8000 Aarhus C, Denmark
| | - Christian B Vægter
- Danish Research Institute of Translational Neuroscience DANDRITE, Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Ole Worms Alle 3, 8000 Aarhus C, Denmark
| | - Henning Andersen
- Department of Neurology, Danish Pain Research Center and IDNC, Aarhus University Hospital, Nørrebrogade, 8000 Aarhus C, Denmark
| | - Leif Østergaard
- Department of Neuroradiology and Center for Functionally Integrative Neuroscience, Aarhus University Hospital, Nørrebrogade, 8000 Aarhus C, Denmark
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, Gilman Drive, La Jolla, California 92093, USA
| | - Troels S Jensen
- Department of Neurology, Danish Pain Research Center and IDNC, Aarhus University Hospital, Nørrebrogade, 8000 Aarhus C, Denmark
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13
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Zhu T, Meng Q, Ji J, Zhang L, Lou X. TLR4 and Caveolin-1 in Monocytes Are Associated With Inflammatory Conditions in Diabetic Neuropathy. Clin Transl Sci 2016; 10:178-184. [PMID: 27981790 PMCID: PMC5421735 DOI: 10.1111/cts.12434] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 11/04/2016] [Indexed: 12/26/2022] Open
Abstract
The purpose of this study was to investigate the expression of TLR4 and caveolin‐1 in monocytes among healthy volunteers as well as those with type‐2 diabetes mellitus (T2DM) and diabetic peripheral neuropathy (DPN). Nineteen healthy control subjects, 18 patients with T2DM, and 20 patients with DPN were enrolled. Toll‐like receptor (TLR)4, caveolin‐1, MyD88, phosphorylated IκB, and plasma TNF‐α and interleukin (IL)‐6 were measured using real‐time polymerase chain reaction, Western blotting, and enzyme‐linked immunosorbent assay. Compared with the other two groups, the DPN group had higher expression of TLR4, MyD88, phosphorylated IκB, TNF‐α, and IL‐6, but significantly lower levels of caveolin‐1 and total IκB in monocytes. Plasma concentrations of TNF‐α and IL‐6 were positively correlated with TLR4 and negatively correlated with caveolin‐1 in patients with DPN. Plasma concentration of TLR4 was negatively correlated with caveolin‐1 in patients with DPN. Reduced expression of caveolin‐1 in monocytes could aggravate the TLR4‐mediated inflammatory cascade.
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Affiliation(s)
- T Zhu
- Department of Anesthesiology, Songjiang Center Hospital, NanJing Medical University, Shanghai, China
| | - Q Meng
- Department of Anesthesiology, Songjiang Center Hospital, NanJing Medical University, Shanghai, China.,Department of Anesthesiology, Nanjing Hospital, Nanjing Medical University & Nanjing First Hospital, Nanjing, China
| | - J Ji
- Department of Anesthesiology, Songjiang Center Hospital, NanJing Medical University, Shanghai, China
| | - L Zhang
- Department of Anesthesiology, Songjiang Center Hospital, NanJing Medical University, Shanghai, China
| | - X Lou
- Department of Central Laboratory, Songjiang Hospital, First People's Hospital, Shanghai Jiao Tong University, Shanghai, China
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14
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Yan L, Xie M, Lu H, Zhang H, Shi M, Zhang Y, Xi C, Li J, Yang T. Anti-Apoptotic Effect of IGF1 on Schwann Exposed to Hyperglycemia is Mediated by Neuritin, a Novel Neurotrophic Factor. Mol Neurobiol 2016; 55:495-505. [PMID: 27966079 DOI: 10.1007/s12035-016-0331-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 11/29/2016] [Indexed: 12/13/2022]
Abstract
The aim of the present study is to explore the effects of exogenous insulin-like growth factor-1 (IGF1) on hyperglycemia-induced apoptosis of Schwann cells via neuritin-mediated pathway. Neuritin was identified with immunohistochemistry. Exogenous IGF1 was used to prevent possible changes in neuritin expression and apoptosis of Schwann cells isolated from rat sciatic nerves and cultured in high-glucose media. Neuritin silencing or overexpressing lentivirus transfection of Schwann cells was conducted. Expressions of neuritin at levels of transcription or translation were measured using quantitative PCR or Western blot. Caspase-3 and caspase-9 fluorometric assays were performed. Bcl-2 and Bax were assayed using Western blotting. Apoptosis of Schwann cells was measured using FACS analysis and TUNEL assay. A pathway of IGF1 action in relation to neuritin was explored. Neuritin and Bcl-2 protein were localized in Schwann cells of rats' sciatic nerves. In vitro, apoptosis increased with downregulated neuritin expression, which was prevented by exogenous IGF1 treatment in contrast to without, in Schwann cells isolated from rat sciatic nerve and cultured in high-glucose and serum-free media. A phosphatidylinositol-3-kinase (PI3K) inhibitor treatment blocked the action of IGF1. The inhibitor did not affect the apoptosis rate that decreased obviously after neuritin was overexpressed in Schwann cells. The apoptosis rate increased drastically after neuritin was silenced, and the resultant apoptosis was suppressed by a caspase inhibitor treatment but not affected by exogenous IGF1. The activities of caspase-3 and caspase-9 changed positively with apoptosis. An anti-apoptotic protein (Bcl-2) not Bax increased or decreased in neuritin-overexpressed or neuritin-silenced Schwann cells, respectively. Bcl-2-selective inhibitor blocked the anti-apoptotic effect of neuritin. IGF1 or neuritin was not found to affect glucose levels in media during the experiment. The anti-apoptotic effect of IGF1 on Schwann cells inflicted by hyperglycemia is mediated at least by neuritin, a novel neurotrophic factor, through PI3K and Bcl-2.
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Affiliation(s)
- Lingfei Yan
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing, 210029, China
| | - Min Xie
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing, 210029, China
| | - He Lu
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing, 210029, China
| | - Hongman Zhang
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing, 210029, China
| | - Min Shi
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing, 210029, China
| | - Yingduan Zhang
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing, 210029, China
| | - Chunhong Xi
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing, 210029, China
| | - Jianbo Li
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing, 210029, China. .,Diabetic Neuropathy Study Group of Chinese Diabetes Society, 42 Dongsi Xidajie, Beijing, China.
| | - Tao Yang
- Endocrinology and Metabolism Department, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing, 210029, China
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15
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Min S, Jian-bo L, Hong-man Z, Ling-fei Y, Min X, Jia-wei C. Neuritin is expressed in Schwann cells and down-regulated in apoptotic Schwann cells under hyperglycemia. Nutr Neurosci 2016; 15:264-70. [PMID: 22782233 DOI: 10.1179/1476830512y.0000000022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
We aimed to explore neuritin expression in Schwann cells under different glucose conditions. Expression of neuritin at the levels of transcription and translation in purified Schwann cells was detected and measured using reverse transcriptase (RT) (quantitative) polymerase chain reaction (PCR) and western blot. Apoptosis of Schwann cells was measured by flow cytometry using Fluorescence Activated Cell Sorter (FACS) analysis and caspase fluorometric assay. Neuritin mRNA and protein were detected in cultured primary Schwann cells. Neuritin was identified as cell membrane form of protein and predominately as secreted or solube form of protein. Neuritin was significantly lower in 150 mM glucose condition, and more significantly lower in 300 mM glucose, than 5.6 mM glucose condition at 36 hours and especially at 48 hours of the culture, respectively (P < 0.05-0.01). In contrast to 5.6 mM glucose, obvious apoptosis of Schwann cells was demonstrated at 42 hours in 300 mM glucose condition and at 48 hours in 150 mM glucose, respectively (P < 0.05-0.01). Neuritin and apoptosis were correlated in a power regression (P < 0.01). 5.6 mM glucose cultured cells did not show these obvious changes during the experiment. It is concluded that neuritin mRNA and protein were expressed and down-regulated in Schwann cells under high-glucose concentration and the down-regulation may contribute to apopotosis of Schwann cells.
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16
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Abstract
Diabetic neuropathy is a common secondary complication of diabetes that impacts on patient's health and well-being. Distal axon degeneration is a key feature of diabetic neuropathy, but the pathological changes which underlie axonal die-back are incompletely understood; despite decades of research a treatment has not yet been identified. Basic research must focus on understanding the complex mechanisms underlying changes that occur in the nervous system during diabetes. To this end, tissue culture techniques are invaluable as they enable researchers to examine the intricate mechanistic responses of cells to high glucose or other factors in order to better understand the pathogenesis of nerve dysfunction. This chapter describes the use of in vitro models to study a wide range of specific cellular effects pertaining to diabetic neuropathy including apoptosis, neurite outgrowth, neurodegeneration, activity, and bioenergetics. We consider problems associated with in vitro modeling and future refinement such as use of induced pluripotent stem cells and microfluidic technology.
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17
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Hou YC, Yang SH, Wu YT, Lai CH. Alterations of neocortico-limbic association fibers and correlation with diet in prediabetes diagnosed by impaired fasting glucose. J Magn Reson Imaging 2016; 43:1500-6. [PMID: 26756544 DOI: 10.1002/jmri.25127] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 12/01/2015] [Indexed: 12/13/2022] Open
Abstract
PURPOSE To assess the existence of alterations in the micro-integrity of the fasciculus in prediabetic subjects. The issue of micro-integrity in white matter tracts has not been adequately addressed in prediabetes. MATERIALS AND METHODS Sixty-four prediabetic subjects and 54 controls were enrolled. All participants completed 24-hour diet records and 3-day diet records and received diffusion tensor imaging at 3T. The data for white matter micro-integrity were analyzed and compared between prediabetic subjects and controls with age and gender as covariates. In addition, voxel-wise regression between white matter micro-integrity, diet, and preprandial glucose levels were used to explore the relationship between white matter micro-integrity and diet or serum glucose levels. RESULTS We found that prediabetic subjects had significant reductions in the micro-integrity of bilateral anterior thalamic radiation, left inferior longitudinal fasciculus, and left superior longitudinal fasciculus (corrected P < 0.05). In addition, total carbohydrate intake amount and preprandial serum glucose levels were negatively correlated with the micro-integrity in the left inferior longitudinal fasciculus and left anterior thalamic radiation (r: -0.47, corrected P < 0.05). CONCLUSION Restrictive alterations in the white matter micro-integrity of the anterior thalamic radiation and inferior and superior longitudinal fasciculi might represent the initial "hot spots" for white matter tract alterations, which might play a role in the development of prediabetes. J. Magn. Reson. Imaging 2016;43:1500-1506.
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Affiliation(s)
- Yi-Cheng Hou
- Department of Nutrition, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City, Taiwan, ROC
| | - Shwu-Huey Yang
- School of Nutrition and Health Sciences, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan, ROC
| | - Yu-Te Wu
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan, ROC.,Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ROC.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Chien-Han Lai
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan, ROC.,Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ROC.,Department of Psychiatry, Cheng Hsin General Hospital, Taipei City, Taiwan, ROC
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18
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Chao HC, Chou CT, Lee YC, Lin KP. Coexistence of Charcot Marie Tooth disease type 1A and diabetes in Taiwan: A clinicopathological study. J Neurol Sci 2015; 358:213-20. [PMID: 26349404 DOI: 10.1016/j.jns.2015.08.1539] [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] [Received: 07/08/2015] [Accepted: 08/26/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Charcot Marie Tooth disease type 1A (CMT1A) is the most commonly inherited demyelinating polyneuropathy with variable phenotypes, affected by several comorbidities, especially diabetes mellitus (DM). Previous studies showed that DM exacerbates the clinical manifestations of CMT1A. PATIENTS AND METHODS We retrospectively evaluated patients with CMT1A in our hospital, and identified three groups among 12 cases, which comprised four patients with CMT1A, four with CMT1A+DM, and four with DM. We reviewed the CMT neuropathy score (CMTNS), electrophysiological data, and histomorphological parameters of the sural nerve, including fiber density, myelin thickness, axon diameter, g-ratio, regenerative clusters, and regeneration ratio. RESULTS The CMTNS was significantly higher in patients with CMT1A+DM (21.5±2.52) than in those with CMT1A only (10.8±4.4; p=0.03). Pathological findings in patients with CMT1A+DM included a significant decrease of myelinated fiber density (p=0.02) and reduction in the regenerative ratio (p=0.01), indicating severe degeneration with impaired regeneration. In non-parametric analyses, DM was found to play a more important role than CMT1A in influencing nerve degeneration and regeneration. CONCLUSIONS In patients with CMT1A, DM exacerbated clinical and pathological manifestations including increased loss of myelinated fibers, abnormal axon-myelin interaction, and impaired nerve regeneration.
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Affiliation(s)
- Hua-Chuan Chao
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC
| | - Cheng-Ta Chou
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC
| | - Yi-Chung Lee
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC; Brain Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC
| | - Kon-Ping Lin
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.
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19
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Bittel DC, Bittel AJ, Tuttle LJ, Hastings MK, Commean PK, Mueller MJ, Cade WT, Sinacore DR. Adipose tissue content, muscle performance and physical function in obese adults with type 2 diabetes mellitus and peripheral neuropathy. J Diabetes Complications 2015; 29:250-7. [PMID: 25547717 PMCID: PMC4333054 DOI: 10.1016/j.jdiacomp.2014.11.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 11/06/2014] [Accepted: 11/06/2014] [Indexed: 12/15/2022]
Abstract
AIMS To determine leg intermuscular (IMAT) and subcutaneous (SQAT) adipose tissue and their relationships with muscle performance and function in obese adults with and without type 2 diabetes and peripheral neuropathy (T2DMPN). METHODS Seventy-nine age-matched obese adults were studied, 13 T2DM, 54 T2DMPN, and 24 obese controls. Leg fat (%IMAT, %SQAT) volumes were quantified using MRI. Ankle plantar flexion (PF) torque and power were assessed with isokinetic dynamometry. Physical function was assessed with 9-item Physical Performance Test (PPT), 6-minute walk distance, single-limb balance, and time to ascend 10 stairs. One-way ANOVAs determined group differences, and multiple regression predicted PPT score from disease status, % IMAT, and PF power. RESULTS T2DMPN participants had 37% greater IMAT volumes and 15% lower SQAT volumes than controls (p =. 01). T2DMPN and T2DM showed reduced PF torque and power compared to controls. T2DMPN participants had lower PPT score, 6-minute walk, single-limb balance, and stair climbing than controls (all p<.05). %IMAT volume correlated inversely, and %SQAT correlated directly, with PPT. Leg %IMAT and disease status predicted 49% of PPT score. CONCLUSIONS T2DMPN may represent a shift in adipose tissue accumulation from SQAT to IMAT depots, which is inversely associated with muscle performance and physical function.
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Affiliation(s)
- Daniel C Bittel
- Program in Physical Therapy, Washington University School of Medicine, 4444 Forest Park Ave, St Louis, MO, 63110.
| | - Adam J Bittel
- Program in Physical Therapy, Washington University School of Medicine, 4444 Forest Park Ave, St Louis, MO, 63110
| | - Lori J Tuttle
- Doctor of Physical Therapy Program, School of Exercise and Nutritional Sciences, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182
| | - Mary K Hastings
- Program in Physical Therapy, Washington University School of Medicine, 4444 Forest Park Ave, St Louis, MO, 63110
| | - Paul K Commean
- Program in Physical Therapy, Washington University School of Medicine, 4444 Forest Park Ave, St Louis, MO, 63110
| | - Michael J Mueller
- Program in Physical Therapy, Washington University School of Medicine, 4444 Forest Park Ave, St Louis, MO, 63110
| | - W Todd Cade
- Program in Physical Therapy, Washington University School of Medicine, 4444 Forest Park Ave, St Louis, MO, 63110
| | - David R Sinacore
- Program in Physical Therapy, Washington University School of Medicine, 4444 Forest Park Ave, St Louis, MO, 63110
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20
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Taiana MM, Lombardi R, Porretta-Serapiglia C, Ciusani E, Oggioni N, Sassone J, Bianchi R, Lauria G. Neutralization of schwann cell-secreted VEGF is protective to in vitro and in vivo experimental diabetic neuropathy. PLoS One 2014; 9:e108403. [PMID: 25268360 PMCID: PMC4182455 DOI: 10.1371/journal.pone.0108403] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 08/27/2014] [Indexed: 11/29/2022] Open
Abstract
The pathogenetic role of vascular endothelial growth factor (VEGF) in long-term retinal and kidney complications of diabetes has been demonstrated. Conversely, little is known in diabetic neuropathy. We examined the modulation of VEGF pathway at mRNA and protein level on dorsal root ganglion (DRG) neurons and Schwann cells (SC) induced by hyperglycaemia. Moreover, we studied the effects of VEGF neutralization on hyperglycemic DRG neurons and streptozotocin-induced diabetic neuropathy. Our findings demonstrated that DRG neurons were not affected by the direct exposition to hyperglycaemia, whereas showed an impairment of neurite outgrowth ability when exposed to the medium of SC cultured in hyperglycaemia. This was mediated by an altered regulation of VEGF and FLT-1 receptors. Hyperglycaemia increased VEGF and FLT-1 mRNA without changing their intracellular protein levels in DRG neurons, decreased intracellular and secreted protein levels without changing mRNA level in SC, while reduced the expression of the soluble receptor sFLT-1 both in DRG neurons and SC. Bevacizumab, a molecule that inhibits VEGF activity preventing the interaction with its receptors, restored neurite outgrowth and normalized FLT-1 mRNA and protein levels in co-cultures. In diabetic rats, it both prevented and restored nerve conduction velocity and nociceptive thresholds. We demonstrated that hyperglycaemia early affected neurite outgrowth through the impairment of SC-derived VEGF/FLT-1 signaling and that the neutralization of SC-secreted VEGF was protective both in vitro and in vivo models of diabetic neuropathy.
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MESH Headings
- Angiogenesis Inhibitors/pharmacology
- Animals
- Antibodies, Monoclonal, Humanized/pharmacology
- Bevacizumab
- Coculture Techniques
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/pathology
- Diabetic Neuropathies/chemically induced
- Diabetic Neuropathies/drug therapy
- Diabetic Neuropathies/genetics
- Diabetic Neuropathies/pathology
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/metabolism
- Ganglia, Spinal/pathology
- Gene Expression Regulation
- Hyperglycemia/chemically induced
- Hyperglycemia/drug therapy
- Hyperglycemia/genetics
- Hyperglycemia/pathology
- Male
- Neural Conduction/drug effects
- Neurites/drug effects
- Neurites/metabolism
- Neurites/pathology
- Nociception/drug effects
- Rats
- Rats, Sprague-Dawley
- Schwann Cells/drug effects
- Schwann Cells/metabolism
- Schwann Cells/pathology
- Sensory Receptor Cells/drug effects
- Sensory Receptor Cells/metabolism
- Sensory Receptor Cells/pathology
- Signal Transduction
- Streptozocin
- Vascular Endothelial Growth Factor A/antagonists & inhibitors
- Vascular Endothelial Growth Factor A/genetics
- Vascular Endothelial Growth Factor A/metabolism
- Vascular Endothelial Growth Factor Receptor-1/genetics
- Vascular Endothelial Growth Factor Receptor-1/metabolism
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Affiliation(s)
- Michela M. Taiana
- Neuroalgology and Headache Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, Milan, Italy
| | - Raffaella Lombardi
- Neuroalgology and Headache Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, Milan, Italy
| | - Carla Porretta-Serapiglia
- Neuroalgology and Headache Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, Milan, Italy
| | - Emilio Ciusani
- Clinical Pathology and Genetics Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, Milan, Italy
| | - Norberto Oggioni
- Department of Neuroscience and Biomedical Technologies, University of Milan Bicocca, Monza, Italy
| | - Jenny Sassone
- Neuroalgology and Headache Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, Milan, Italy
| | - Roberto Bianchi
- Neuroalgology and Headache Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, Milan, Italy
| | - Giuseppe Lauria
- Neuroalgology and Headache Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, Milan, Italy
- * E-mail:
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21
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Calcium signalling in sensory neurones and peripheral glia in the context of diabetic neuropathies. Cell Calcium 2014; 56:362-71. [PMID: 25149565 DOI: 10.1016/j.ceca.2014.07.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/11/2014] [Accepted: 07/12/2014] [Indexed: 12/14/2022]
Abstract
Peripheral sensory nervous system is comprised of neurones with their axons and neuroglia that includes satellite glial cells in sensory ganglia, myelinating, non-myelinating and perisynaptic Schwann cells. Pathogenesis of peripheral diabetic polyneuropathies is associated with aberrant function of both neurones and glia. Deregulated Ca(2+) homoeostasis and aberrant Ca(2+) signalling in neuronal and glial elements contributes to many forms of neuropathology and is fundamental to neurodegenerative diseases. In diabetes both neurones and glia experience metabolic stress and mitochondrial dysfunction which lead to deregulation of Ca(2+) homeostasis and Ca(2+) signalling, which in their turn lead to pathological cellular reactions contributing to development of diabetic neuropathies. Molecular cascades responsible for Ca(2+) homeostasis and signalling, therefore, can be regarded as potential therapeutic targets.
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22
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23
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24
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Induction of heat shock protein 70 (Hsp70) prevents neuregulin-induced demyelination by enhancing the proteasomal clearance of c-Jun. ASN Neuro 2012; 4:e00102. [PMID: 23240583 PMCID: PMC3517131 DOI: 10.1042/20120047] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Modulating molecular chaperones is emerging as an attractive approach to treat neurodegenerative diseases associated with protein aggregation, DPN (diabetic peripheral neuropathy) and possibly, demyelinating neuropathies. KU-32 [N-(7-((2R,3R,4S,5R)-3,4-dihydroxy-5-methoxy-6,6-dimethyl-tetrahydro-2H-pyran-2-yloxy)-8-methyl-2-oxo-2H-chromen-3-yl)acetamide] is a small molecule inhibitor of Hsp90 (heat shock protein 90) and reverses sensory deficits associated with myelinated fibre dysfunction in DPN. Additionally, KU-32 prevented the loss of myelinated internodes induced by treating myelinated SC (Schwann cell)-DRG (dorsal root ganglia) sensory neuron co-cultures with NRG1 (neuregulin-1 Type 1). Since KU-32 decreased NRG1-induced demyelination in an Hsp70-dependent manner, the goal of the current study was to clarify how Hsp70 may be mechanistically linked to preventing demyelination. The activation of p42/p44 MAPK (mitogen-activated protein kinase) and induction of the transcription factor c-Jun serve as negative regulators of myelination. NRG1 activated MAPK, induced c-Jun expression and promoted a loss of myelin segments in DRG explants isolated from both WT (wild-type) and Hsp70 KO (knockout) mice. Although KU-32 did not block the activation of MAPK, it blocked c-Jun induction and protected against a loss of myelinated segments in WT mice. In contrast, KU-32 did not prevent the NRG1-dependent induction of c-Jun and loss of myelin segments in explants from Hsp70 KO mice. Overexpression of Hsp70 in myelinated DRG explants prepared from WT or Hsp70 KO mice was sufficient to block the induction of c-Jun and the loss of myelin segments induced by NRG1. Lastly, inhibiting the proteasome prevented KU-32 from decreasing c-Jun levels. Collectively, these data support that Hsp70 induction is sufficient to prevent NRG1-induced demyelination by enhancing the proteasomal degradation of c-Jun.
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25
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Calizo RC, Scarlata S. A role for G-proteins in directing G-protein-coupled receptor-caveolae localization. Biochemistry 2012; 51:9513-23. [PMID: 23102276 PMCID: PMC3507317 DOI: 10.1021/bi301107p] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Caveolae are membrane domains that may influence cell
signaling
by sequestering specific proteins such as G-protein-coupled receptors
(GPCRs). While previous reports largely show that Gαq subunits, but not other G-proteins, interact strongly with the caveolae
protein, Caveolin-1 (Cav1), the inclusion of GPCRs in caveolae is
controversial. Here, we have used fluorescence methods to determine
the effect of caveolae on the physical and functional properties of
two GPCRs that have been reported to reside in caveolae, bradykinin
receptor type 2 (B2R), which is coupled to Gαq, and the μ-opioid receptor (μOR), which is coupled
to Gαi. While caveolae do not affect cAMP signals
mediated by μOR, they prolong Ca2+ signals mediated
by B2R. In A10 cells that endogenously express B2R and Cav1, downregulation of Cav1 ablates the prolonged recovery
seen upon bradykinin stimulation in accord with the idea that the
presence of caveolae prolongs Gαq activation. Immunofluorescence
and Förster resonance energy transfer (FRET) studies show that
a significant fraction of B2R resides at or close to caveolae
domains while none or very little μOR resides in caveolae domains.
The level of FRET between B2R and caveolae is reduced by
downregulation of Gαq or by addition of a peptide
that interferes with Gαq–Caveolin-1 interactions,
suggesting that Gαq promotes localization of B2R to caveolae domains. Our results lead to the suggestion
that Gαq can localize its associated receptors to
caveolae domains to enhance their signals.
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Affiliation(s)
- Rhodora Cristina Calizo
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
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26
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Farmer KL, Li C, Dobrowsky RT. Diabetic peripheral neuropathy: should a chaperone accompany our therapeutic approach? Pharmacol Rev 2012; 64:880-900. [PMID: 22885705 DOI: 10.1124/pr.111.005314] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) is a common complication of diabetes that is associated with axonal atrophy, demyelination, blunted regenerative potential, and loss of peripheral nerve fibers. The development and progression of DPN is due in large part to hyperglycemia but is also affected by insulin deficiency and dyslipidemia. Although numerous biochemical mechanisms contribute to DPN, increased oxidative/nitrosative stress and mitochondrial dysfunction seem intimately associated with nerve dysfunction and diminished regenerative capacity. Despite advances in understanding the etiology of DPN, few approved therapies exist for the pharmacological management of painful or insensate DPN. Therefore, identifying novel therapeutic strategies remains paramount. Because DPN does not develop with either temporal or biochemical uniformity, its therapeutic management may benefit from a multifaceted approach that inhibits pathogenic mechanisms, manages inflammation, and increases cytoprotective responses. Finally, exercise has long been recognized as a part of the therapeutic management of diabetes, and exercise can delay and/or prevent the development of painful DPN. This review presents an overview of existing therapies that target both causal and symptomatic features of DPN and discusses the role of up-regulating cytoprotective pathways via modulating molecular chaperones. Overall, it may be unrealistic to expect that a single pharmacologic entity will suffice to ameliorate the multiple symptoms of human DPN. Thus, combinatorial therapies that target causal mechanisms and enhance endogenous reparative capacity may enhance nerve function and improve regeneration in DPN if they converge to decrease oxidative stress, improve mitochondrial bioenergetics, and increase response to trophic factors.
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Affiliation(s)
- Kevin L Farmer
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS 66045, USA
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27
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Zhang L, Zhao H, Blagg BSJ, Dobrowsky RT. C-terminal heat shock protein 90 inhibitor decreases hyperglycemia-induced oxidative stress and improves mitochondrial bioenergetics in sensory neurons. J Proteome Res 2012; 11:2581-93. [PMID: 22413817 DOI: 10.1021/pr300056m] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Diabetic peripheral neuropathy (DPN) is a common complication of diabetes in which hyperglycemia-induced mitochondrial dysfunction and enhanced oxidative stress contribute to sensory neuron pathology. KU-32 is a novobiocin-based, C-terminal inhibitor of the molecular chaperone, heat shock protein 90 (Hsp90). KU-32 ameliorates multiple sensory deficits associated with the progression of DPN and protects unmyelinated sensory neurons from glucose-induced toxicity. Mechanistically, KU-32 increased the expression of Hsp70, and this protein was critical for drug efficacy in reversing DPN. However, it remained unclear if KU-32 had a broader effect on chaperone induction and if its efficacy was linked to improving mitochondrial dysfunction. Using cultures of hyperglycemically stressed primary sensory neurons, the present study investigated whether KU-32 had an effect on the translational induction of other chaperones and improved mitochondrial oxidative stress and bioenergetics. A variation of stable isotope labeling with amino acids in cell culture called pulse SILAC (pSILAC) was used to unbiasedly assess changes in protein translation. Hyperglycemia decreased the translation of numerous mitochondrial proteins that affect superoxide levels and respiratory activity. Importantly, this correlated with a decrease in mitochondrial oxygen consumption and an increase in superoxide levels. KU-32 increased the translation of Mn superoxide dismutase and several cytosolic and mitochondrial chaperones. Consistent with these changes, KU-32 decreased mitochondrial superoxide levels and significantly enhanced respiratory activity. These data indicate that efficacy of modulating molecular chaperones in DPN may be due in part to improved neuronal mitochondrial bioenergetics and decreased oxidative stress.
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Affiliation(s)
- Liang Zhang
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, Kansas 66045, United States
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Modulating molecular chaperones improves sensory fiber recovery and mitochondrial function in diabetic peripheral neuropathy. Exp Neurol 2012; 235:388-96. [PMID: 22465570 DOI: 10.1016/j.expneurol.2012.03.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 03/03/2012] [Accepted: 03/12/2012] [Indexed: 12/20/2022]
Abstract
Quantification of intra-epidermal nerve fibers (iENFs) is an important approach to stage diabetic peripheral neuropathy (DPN) and is a promising clinical endpoint for identifying beneficial therapeutics. Mechanistically, diabetes decreases neuronal mitochondrial function and enhancing mitochondrial respiratory capacity may aid neuronal recovery from glucotoxic insults. We have proposed that modulating the activity and expression of heat shock proteins (Hsp) may be of benefit in treating DPN. KU-32 is a C-terminal Hsp90 inhibitor that improved thermal hypoalgesia in diabetic C57Bl/6 mice but it was not determined if this was associated with an increase in iENF density and mitochondrial function. After 16 weeks of diabetes, Swiss Webster mice showed decreased electrophysiological and psychosensory responses and a >30% loss of iENFs. Treatment of the mice with ten weekly doses of 20mg/kg KU-32 significantly reversed pre-existing deficits in nerve conduction velocity and responses to mechanical and thermal stimuli. KU-32 therapy significantly reversed the pre-existing loss of iENFs despite the identification of a sub-group of drug-treated diabetic mice that showed improved thermal sensitivity but no increase in iENF density. To determine if the improved clinical indices correlated with enhanced mitochondrial activity, sensory neurons were isolated and mitochondrial bioenergetics assessed ex vivo using extracellular flux technology. Diabetes decreased maximal respiratory capacity in sensory neurons and this deficit was improved following KU-32 treatment. In conclusion, KU-32 improved physiological and morphologic markers of degenerative neuropathy and drug efficacy may be related to enhanced mitochondrial bioenergetics in sensory neurons.
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Chowdhury SKR, Smith DR, Fernyhough P. The role of aberrant mitochondrial bioenergetics in diabetic neuropathy. Neurobiol Dis 2012; 51:56-65. [PMID: 22446165 DOI: 10.1016/j.nbd.2012.03.016] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 02/22/2012] [Accepted: 03/01/2012] [Indexed: 02/07/2023] Open
Abstract
Diabetic neuropathy is a neurological complication of diabetes that causes significant morbidity and, because of the obesity-driven rise in incidence of type 2 diabetes, is becoming a major international health problem. Mitochondrial phenotype is abnormal in sensory neurons in diabetes and may contribute to the etiology of diabetic neuropathy where a distal dying-back neurodegenerative process is a key component contributing to fiber loss. This review summarizes the major features of mitochondrial dysfunction in neurons and Schwann cells in human diabetic patients and in experimental animal models (primarily exhibiting type 1 diabetes). This article attempts to relate these findings to the development of critical neuropathological hallmarks of the disease. Recent work reveals that hyperglycemia in diabetes triggers nutrient excess in neurons that, in turn, mediates a phenotypic change in mitochondrial biology through alteration of the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) signaling axis. This vital energy sensing metabolic pathway modulates mitochondrial function, biogenesis and regeneration. The bioenergetic phenotype of mitochondria in diabetic neurons is aberrant due to deleterious alterations in expression and activity of respiratory chain components as a direct consequence of abnormal AMPK/PGC-1α signaling. Utilization of innovative respirometry equipment to analyze mitochondrial function of cultured adult sensory neurons from diabetic rodents shows that the outcome for cellular bioenergetics is a reduced adaptability to fluctuations in ATP demand. The diabetes-induced maladaptive process is hypothesized to result in exhaustion of the ATP supply in the distal nerve compartment and induction of nerve fiber dissolution. The role of mitochondrial dysfunction in the etiology of diabetic neuropathy is compared with other types of neuropathy with a distal dying-back pathology such as Friedreich ataxia, Charcot-Marie-Tooth disease type 2 and human immunodeficiency virus-associated distal-symmetric neuropathy.
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Affiliation(s)
- Subir K Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada
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Hur J, Sullivan KA, Pande M, Hong Y, Sima AAF, Jagadish HV, Kretzler M, Feldman EL. The identification of gene expression profiles associated with progression of human diabetic neuropathy. ACTA ACUST UNITED AC 2011; 134:3222-35. [PMID: 21926103 DOI: 10.1093/brain/awr228] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Diabetic neuropathy is a common complication of diabetes. While multiple pathways are implicated in the pathophysiology of diabetic neuropathy, there are no specific treatments and no means to predict diabetic neuropathy onset or progression. Here, we identify gene expression signatures related to diabetic neuropathy and develop computational classification models of diabetic neuropathy progression. Microarray experiments were performed on 50 samples of human sural nerves collected during a 52-week clinical trial. A series of bioinformatics analyses identified differentially expressed genes and their networks and biological pathways potentially responsible for the progression of diabetic neuropathy. We identified 532 differentially expressed genes between patient samples with progressing or non-progressing diabetic neuropathy, and found these were functionally enriched in pathways involving inflammatory responses and lipid metabolism. A literature-derived co-citation network of the differentially expressed genes revealed gene subnetworks centred on apolipoprotein E, jun, leptin, serpin peptidase inhibitor E type 1 and peroxisome proliferator-activated receptor gamma. The differentially expressed genes were used to classify a test set of patients with regard to diabetic neuropathy progression. Ridge regression models containing 14 differentially expressed genes correctly classified the progression status of 92% of patients (P < 0.001). To our knowledge, this is the first study to identify transcriptional changes associated with diabetic neuropathy progression in human sural nerve biopsies and describe their potential utility in classifying diabetic neuropathy. Our results identifying the unique gene signature of patients with progressive diabetic neuropathy will facilitate the development of new mechanism-based diagnostics and therapies.
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Affiliation(s)
- Junguk Hur
- Bioinformatics Program, University of Michigan, Ann Arbor, MI 48109, USA
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Padilla A, Descorbeth M, Almeyda AL, Payne K, De Leon M. Hyperglycemia magnifies Schwann cell dysfunction and cell death triggered by PA-induced lipotoxicity. Brain Res 2010; 1370:64-79. [PMID: 21108938 DOI: 10.1016/j.brainres.2010.11.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 11/01/2010] [Accepted: 11/05/2010] [Indexed: 01/01/2023]
Abstract
Lipid overload resulting in lipotoxicity is prominent in a number of chronic diseases and has been associated with cellular dysfunction and cell death. This study characterizes palmitic acid-induced lipotoxicity (PA-LTx) in Schwann cell cultures grown in normal and high glucose concentrations. The study shows for the first time that Schwann cell (SC) cultures exposed to elevated levels of PA exhibit a dose- and time-dependent loss in cell viability. Hoescht and Annexin V/7AAD staining confirmed cell death through apoptosis and the lipotoxic effect was more dramatic in SC cultures grown under high glucose conditions. The first indication of cellular dysfunction in treated SC cultures was a decrease in Ca(++) levels in the endoplasmic reticulum (ER, [Ca(++)](ER)) observed five minutes following the initial challenge with PA. This decrease in [Ca(++) ](ER) was followed by a significant increase in the expression of ER stress signature genes CHOP, Xbp1 and GRP78. The early ER stress response induced by PA-LTx was followed by a strong mitochondrial membrane depolarization. Flow cytometry using 2', 7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) showed an increase in oxidative stress within three to six hours after PA treatment. Treatment of cultures undergoing PA-LTx with the calcium chelator BAPTA-AM and the anti-oxidant MCI-186 significantly reversed the lipotoxic effect by decreasing the generation of ROS and significantly increasing cell viability. We conclude that lipotoxicity in Schwann cells results in cellular dysfunction and cell death that involves a robust ER stress response, mitochondrial dysfunction and an augmented state of cellular oxidative stress (ASCOS).
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Affiliation(s)
- Amelia Padilla
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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Inhibiting heat-shock protein 90 reverses sensory hypoalgesia in diabetic mice. ASN Neuro 2010; 2:e00040. [PMID: 20711301 PMCID: PMC2919983 DOI: 10.1042/an20100015] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 07/08/2010] [Accepted: 07/14/2010] [Indexed: 01/07/2023] Open
Abstract
Increasing the expression of Hsp70 (heat-shock protein 70) can inhibit sensory neuron degeneration after axotomy. Since the onset of DPN (diabetic peripheral neuropathy) is associated with the gradual decline of sensory neuron function, we evaluated whether increasing Hsp70 was sufficient to improve several indices of neuronal function. Hsp90 is the master regulator of the heat-shock response and its inhibition can up-regulate Hsp70. KU-32 (N-{7-[(2R,3R,4S,5R)-3,4-dihydroxy-5-methoxy-6,6-dimethyl-tetrahydro-2H-pyran-2-yloxy]-8-methyl-2-oxo-2H-chromen-3-yl}acetamide) was developed as a novel, novobiocin-based, C-terminal inhibitor of Hsp90 whose ability to increase Hsp70 expression is linked to the presence of an acetamide substitution of the prenylated benzamide moiety of novobiocin. KU-32 protected against glucose-induced death of embryonic DRG (dorsal root ganglia) neurons cultured for 3 days in vitro. Similarly, KU-32 significantly decreased neuregulin 1-induced degeneration of myelinated Schwann cell DRG neuron co-cultures prepared from WT (wild-type) mice. This protection was lost if the co-cultures were prepared from Hsp70.1 and Hsp70.3 KO (knockout) mice. KU-32 is readily bioavailable and was administered once a week for 6 weeks at a dose of 20 mg/kg to WT and Hsp70 KO mice that had been rendered diabetic with streptozotocin for 12 weeks. After 12 weeks of diabetes, both WT and Hsp70 KO mice developed deficits in NCV (nerve conduction velocity) and a sensory hypoalgesia. Although KU-32 did not improve glucose levels, HbA1c (glycated haemoglobin) or insulin levels, it reversed the NCV and sensory deficits in WT but not Hsp70 KO mice. These studies provide the first evidence that targeting molecular chaperones reverses the sensory hypoalgesia associated with DPN.
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Key Words
- AM, acetoxymethyl ester
- DAPI, 4′,6-diamidino-2-phenylindole
- DMEM, Dulbecco's modified Eagle's medium
- DPN, diabetic peripheral neuropathy
- DRG, dorsal root ganglion
- Drp1, dynamin-related protein 1
- FBG, fasting blood glucose
- FCS, fetal calf serum
- HSF1, heat-shock factor 1
- HSR, heat-shock response
- Hsc70, heat-shock cognate 70 stress protein
- Hsp90, heat-shock protein 90
- JNK, c-Jun N-terminal kinase
- KO, knockout
- KU-32, N-{7-[(2R,3R,4S,5R)-3,4-dihydroxy-5-methoxy-6,6-dimethyl-tetrahydro-2H-pyran-2-yloxy]-8-methyl-2-oxo-2H-chromen-3-yl}acetamide
- LC-MS, liquid chromatography MS
- MBP, myelin basic protein
- MNCV, motor NCV
- NCV, nerve conduction velocity
- NGF, nerve growth factor
- NRG1, human recombinant neuregulin-1-β1 epidermal growth factor domain
- SC-DRG, Schwann cell DRG
- SNCV, sensory NCV
- STZ, streptozotocin
- WT, wild-type
- diabetic neuropathy
- dorsal root ganglia neuron
- heat-shock protein 70
- molecular chaperone
- nerve conduction velocity
- neurodegeneration
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Schmitz M, Klöppner S, Klopfleisch S, Möbius W, Schwartz P, Zerr I, Althaus HH. Mutual effects of caveolin and nerve growth factor signaling in pig oligodendrocytes. J Neurosci Res 2010; 88:572-88. [PMID: 19795378 DOI: 10.1002/jnr.22235] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Signaling of growth factors may depend on the recruitment of their receptors to specialized microdomains. Previous reports on PC12 cells indicated an interaction of raft-organized caveolin and TrkA signaling. Because porcine oligodendrocytes (OLs) respond to nerve growth factor (NGF), we were interested to know whether caveolin also plays a role in oligodendroglial NGF/TrkA signaling. OLs expressed caveolin at the plasma membrane but also intracellularly. This was partially organized in the classically Omega-shaped invaginations, which may represent caveolae. We could show that caveolin and TrkA colocalize by using a discontinuous sucrose gradient (Song et al. [1996] J. Biol. Chem. 271:9690-9697), MACS technology, and immunoprecipitation. However, differential extraction of caveolin and TrkA with Triton X-100 at 4 degrees C indicated that caveolin and TrkA are probably not exclusively present in detergent-resistant, caveolin-containing rafts (CCRs). NGF treatment of OLs up-regulated the expression of caveolin-1 (cav-1) and stimulated tyrosine-14 phosphorylation of cav-1. Furthermore, OLs were transfected with cav-1-specific small interfering RNA (siRNA). A knockdown of cav-1 resulted in a reduced activation of downstream components of the NGF signaling cascade, such as p21Ras and mitogen-activated protein kinase (MAPK) after NGF exposure of OLs. Subsequently, increased oligodendroglial process formation via NGF was impaired. The present study indicates that CCRs/caveolin could play a modulating role during oligodendroglial differentiation and regeneration.
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Affiliation(s)
- Matthias Schmitz
- RU Neural Regeneration, Max-Planck Institute of Experimental Medicine, Goettingen, Germany.
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Zhang L, Yu C, Vasquez FE, Galeva N, Onyango I, Swerdlow RH, Dobrowsky RT. Hyperglycemia alters the schwann cell mitochondrial proteome and decreases coupled respiration in the absence of superoxide production. J Proteome Res 2010; 9:458-71. [PMID: 19905032 DOI: 10.1021/pr900818g] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hyperglycemia-induced mitochondrial dysfunction contributes to sensory neuron pathology in diabetic neuropathy. Although Schwann cells (SCs) also undergo substantial degeneration in diabetic neuropathy, the effect of hyperglycemia on the SC mitochondrial proteome and mitochondrial function has not been examined. Stable isotope labeling with amino acids in cell culture (SILAC) was used to quantify the temporal effect of hyperglycemia on the mitochondrial proteome of primary SCs isolated from neonatal rats. Of 317 mitochondrial proteins identified, about 78% were quantified and detected at multiple time points. Pathway analysis indicated that proteins associated with mitochondrial dysfunction, oxidative phosphorylation, the TCA cycle, and detoxification were significantly increased in expression and over-represented. Assessing mitochondrial respiration in intact SCs indicated that hyperglycemia increased the overall rate of oxygen consumption but decreased the efficiency of coupled respiration. Although a glucose-dependent increase in superoxide production occurs in embryonic sensory neurons, hyperglycemia did not induce a substantial change in superoxide levels in SCs. This correlated with a 1.9-fold increase in Mn superoxide dismutase expression, which was confirmed by immunoblot and enzymatic activity assays. These data support that hyperglycemia alters mitochondrial respiration and can cause remodeling of the SC mitochondrial proteome independent of significant contributions from glucose-induced superoxide production.
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Affiliation(s)
- Liang Zhang
- Department of Pharmacology and Toxicology and Analytic Proteomics Laboratory, University of Kansas, Lawrence, Kansas 66045, USA
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Fernyhough P, Roy Chowdhury SK, Schmidt RE. Mitochondrial stress and the pathogenesis of diabetic neuropathy. Expert Rev Endocrinol Metab 2010; 5:39-49. [PMID: 20729997 PMCID: PMC2924887 DOI: 10.1586/eem.09.55] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Diabetic neuropathy is a major complication of diabetes that affects the sensory and autonomic nervous systems and leads to significant morbidity and impact on quality of life of patients. Mitochondrial stress has been proposed as a major mediator of neurodegeneration in diabetes. This review briefly summarizes the nature of sensory and autonomic nerve dysfunction and presents these findings in the context of diabetes-induced nerve degeneration mediated by alterations in mitochondrial ultrastructure, physiology and trafficking. Diabetes-induced dysfunction in calcium homeostasis is discussed at length and causative associations with sub-optimal mitochondrial physiology are developed. It is clear that across a range of complications of diabetes that mitochondrial physiology is impaired, in general a reduction in electron transport chain capability is apparent. This abnormal activity may predispose mitochondria to generate elevated reactive oxygen species (ROS), although experimental proof remains lacking, but more importantly will deleteriously alter the bioenergetic status of neurons. It is proposed that the next five years of research should focus on identifying changes in mitochondrial phenotype and associated cellular impact, identifying sources of ROS in neurons and analyzing mitochondrial trafficking under diabetic conditions.
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Affiliation(s)
- Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, R4046 - 351 Taché Avenue, Winnipeg, MB R2H 2A6, Canada and Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada, Tel: (204) 235 3692
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36
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Fernyhough P, Calcutt NA. Abnormal calcium homeostasis in peripheral neuropathies. Cell Calcium 2009; 47:130-9. [PMID: 20034667 DOI: 10.1016/j.ceca.2009.11.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 11/17/2009] [Indexed: 01/02/2023]
Abstract
Abnormal neuronal calcium (Ca2+) homeostasis has been implicated in numerous diseases of the nervous system. The pathogenesis of two increasingly common disorders of the peripheral nervous system, namely neuropathic pain and diabetic polyneuropathy, has been associated with aberrant Ca2+ channel expression and function. Here we review the current state of knowledge regarding the role of Ca2+ dyshomeostasis and associated mitochondrial dysfunction in painful and diabetic neuropathies. The central impact of both alterations of Ca2+ signalling at the plasma membrane and also intracellular Ca2+ handling on sensory neurone function is discussed and related to abnormal endoplasmic reticulum performance. We also present new data highlighting sub-optimal axonal Ca2+ signalling in diabetic neuropathy and discuss the putative role for this abnormality in the induction of axonal degeneration in peripheral neuropathies. The accumulating evidence implicating Ca2+ dysregulation in both painful and degenerative neuropathies, along with recent advances in understanding of regional variations in Ca2+ channel and pump structures, makes modulation of neuronal Ca2+ handling an increasingly viable approach for therapeutic interventions against the painful and degenerative aspects of many peripheral neuropathies.
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Affiliation(s)
- Paul Fernyhough
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada R3E0T6.
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McGuire JF, Rouen S, Siegfreid E, Wright DE, Dobrowsky RT. Caveolin-1 and altered neuregulin signaling contribute to the pathophysiological progression of diabetic peripheral neuropathy. Diabetes 2009; 58:2677-86. [PMID: 19675140 PMCID: PMC2768162 DOI: 10.2337/db09-0594] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Evaluate if Erb B2 activation and the loss of caveolin-1 (Cav1) contribute to the pathophysiological progression of diabetic peripheral neuropathy (DPN). RESEARCH DESIGN AND METHODS Cav1 knockout and wild-type C57BL/6 mice were rendered diabetic with streptozotocin, and changes in motor nerve conduction velocity (MNCV), mechanical and thermal hypoalgesia, Erb B2 phosphorylation (pErb B2), and epidermal nerve fiber density were assessed. The contribution of Erb B2 to DPN was assessed using the Erb B2 inhibitors PKI 166 and erlotinib and a conditional bitransgenic mouse that expressed a constitutively active form of Erb B2 in myelinated Schwann cells (SCs). RESULTS Diabetic mice exhibited decreased MNCV and mechanical and thermal sensitivity, but the extent of these deficits was more severe in diabetic Cav1 knockout mice. Diabetes increased pErb B2 levels in both genotypes, but the absence of Cav1 correlated with a greater increase in pErb B2. Erb B2 activation contributed to the mechanical hypoalgesia and MNCV deficits in both diabetic genotypes because treatment with erlotinib or PKI 166 improved these indexes of DPN. Similarly, induction of a constitutively active Erb B2 in myelinated SCs was sufficient to decrease MNCV and induce a mechanical hypoalgesia in the absence of diabetes. CONCLUSIONS Increased Erb B2 activity contributes to specific indexes of DPN, and Cav1 may be an endogenous regulator of Erb B2 signaling. Altered Erb B2 signaling is a novel mechanism that contributes to SC dysfunction in diabetes, and inhibiting Erb B2 may ameliorate deficits of tactile sensitivity in DPN.
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Affiliation(s)
- James F. McGuire
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas
| | - Shefali Rouen
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas
| | - Eric Siegfreid
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas
| | - Douglas E. Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas
| | - Rick T. Dobrowsky
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas
- Corresponding author: Rick T. Dobrowsky,
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Melli G, Höke A. Dorsal Root Ganglia Sensory Neuronal Cultures: a tool for drug discovery for peripheral neuropathies. Expert Opin Drug Discov 2009; 4:1035-1045. [PMID: 20657751 DOI: 10.1517/17460440903266829] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND: Peripheral neuropathies affect many people worldwide and are caused by or associated with a wide range of conditions, both genetic and acquired. Current therapies are directed at symptomatic control because no effective regenerative treatment exists. Primary challenge is that mechanisms that lead to distal axonal degeneration, a common feature of all peripheral neuropathies, are largely unknown. OBJECTIVE/METHODS: To address the role and specific characteristics of dorsal root ganglia (DRG) derived sensory neuron culture system as a useful model in evaluating the pathogenic mechanisms of peripheral neuropathies and examination and validation of potential therapeutic compounds. A thorough review of the recent literature was completed and select examples of the use of DRG neurons in different peripheral neuropathy models were chosen to highlight the utility of these cultures. CONCLUSION: Many useful models of different peripheral neuropathies have been developed using DRG neuronal culture and potential therapeutic targets have been examined, but so far none of the potential therapeutic compounds have succeeded in clinical trials. In recent years, focus has changed to evaluation of axon degeneration as the primary outcome measure advocating a drug development strategy starting with phenotypic drug screening, followed by validation in primary complex co-cultures and animal models.
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Affiliation(s)
- Giorgia Melli
- Istituto Nazionale Neurologico Carlo Besta, Milano, Italy
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Zherebitskaya E, Akude E, Smith DR, Fernyhough P. Development of selective axonopathy in adult sensory neurons isolated from diabetic rats: role of glucose-induced oxidative stress. Diabetes 2009; 58:1356-64. [PMID: 19252136 PMCID: PMC2682687 DOI: 10.2337/db09-0034] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Reactive oxygen species (ROS) are pro-oxidant factors in distal neurodegeneration in diabetes. We tested the hypothesis that sensory neurons exposed to type 1 diabetes would exhibit enhanced ROS and oxidative stress and determined whether this stress was associated with abnormal axon outgrowth. RESEARCH DESIGN AND METHODS Lumbar dorsal root ganglia sensory neurons from normal or 3- to 5-month streptozotocin (STZ)-diabetic rats were cultured with 10 or 25-50 mmol/l glucose. Cell survival and axon outgrowth were assessed. ROS were analyzed using confocal microscopy. Immunofluorescent staining detected expression of manganese superoxide dismutase (MnSOD) and adducts of 4-hydroxy-2-nonenal (4-HNE), and MitoFluor Green dye detected mitochondria. RESULTS Dorsal root ganglion neurons from normal rats exposed to 25-50 mmol/l glucose did not exhibit oxidative stress or cell death. Cultures from diabetic rats exhibited a twofold (P < 0.001) elevation of ROS in axons after 24 h in 25 mmol/l glucose compared with 10 mmol/l glucose or mannitol. Perikarya exhibited no change in ROS levels. Axonal outgrowth was reduced by approximately twofold (P < 0.001) in diabetic cultures compared with control, as was expression of MnSOD. The antioxidant N-acetyl-cysteine (1 mmol/l) lowered axonal ROS levels, normalized aberrant axonal structure, and prevented deficits in axonal outgrowth in diabetic neurons (P < 0.05). CONCLUSIONS Dorsal root ganglia neurons with a history of diabetes expressed low MnSOD and high ROS in axons. Oxidative stress was initiated by high glucose concentration in neurons with an STZ-induced diabetic phenotype. Induction of ROS was associated with impaired axonal outgrowth and aberrant dystrophic structures that may precede or predispose the axon to degeneration and dissolution in human diabetic neuropathy.
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Affiliation(s)
- Elena Zherebitskaya
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada
| | - Eli Akude
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Darrell R. Smith
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
- Corresponding author: Paul Fernyhough,
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40
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Obrosova IG. Diabetes and the peripheral nerve. Biochim Biophys Acta Mol Basis Dis 2008; 1792:931-40. [PMID: 19061951 DOI: 10.1016/j.bbadis.2008.11.005] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2008] [Revised: 11/05/2008] [Accepted: 11/06/2008] [Indexed: 12/11/2022]
Abstract
Diabetes-induced damage to peripheral nerve culminates in development of peripheral diabetic neuropathy (PDN), one of the most devastating complications of diabetes mellitus and a leading cause of foot amputation. The pathogenesis of PDN occurs as a consequence of complex interactions among multiple hyperglycemia-initiated mechanisms, impaired insulin signaling, inflammation, hypertension, and disturbances of fatty acid and lipid metabolism. This review describes experimental new findings in animal and cell culture models as well as clinical data suggesting the importance of 1) previously established hyperglycemia-initiated mechanisms such as increased aldose reductase activity, non-enzymatic glycation/glycooxidation, activation of protein kinase C, 2) oxidative-nitrosative stress and poly(ADP-ribose) polymerase activation; 3) mitogen-activated protein kinase and cyclooxygenase-2 activation, impaired Ca(++) homeostasis and signaling, and several other mechanisms, in PDN.
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Affiliation(s)
- Irina G Obrosova
- Pennington Biomedical Research Center, Louisiana State University, 6400 Perkins Road, Baton Rouge, Louisiana 70808, USA.
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