title: Diabetes-induced central neuritic dystrophy and cognitive deficits are associated with the formation of oligomeric reticulon-3 via oxidative stress.
abstract: Diabetes is a high risk factor to dementia. To investigate the molecular mechanism of diabetic dementia, we induced type 2 diabetes in rats and examined potential changes in their cognitive functions and the neural morphology of the brains. We found that the diabetic rats with an impairment of spatial learning and memory showed the occurrence of RTN3-immunoreactive dystrophic neurites in the cortex. Biochemical examinations revealed the increase of a high molecular weight form of RTN3 (HW-RTN3) in diabetic brains. The corresponding decrease of monomeric RTN3 was correlated with the reduction of its inhibitory effects on the activity of β-secretase (BACE1), a key enzyme for generation of β-amyloid peptides. The results from immunoprecipitation combined with protein carbonyl detection showed that carbonylated RTN3 was significantly higher in cortical tissues of diabetic rats compared with control rats, indicating that diabetes-induced oxidative stress led to RTN3 oxidative damage. In neuroblastoma SH-SY5Y cells, high glucose and/or H2O2 treatment significantly increased the amounts of carbonylated proteins and HW-RTN3, whereas monomeric RTN3 was reduced. Hence, we conclude that diabetes-induced cognitive deficits and central neuritic dystrophy are correlated with the formation of aggregated RTN3 via oxidative stress. We provided the first evidence that oxidative damage caused the formation of toxic RTN3 aggregates, which participated in the pathogenesis of central neuritic dystrophy in diabetic brain. Present findings may offer a new therapeutic strategy to prevent or reduce diabetic dementia.
authors.affiliation: Institutes for Biomedical Science and Department of Neurobiology of the School of Basic Medical Sciences, Shanghai 200032.
authors.forename: Bei
authors.initials: B
authors.lastname: Zhao
authors.forename: Bai-Shen
authors.initials: BS
authors.lastname: Pan
authors.forename: Su-Wen
authors.initials: SW
authors.lastname: Shen
authors.forename: Xiao
authors.initials: X
authors.lastname: Sun
authors.forename: Zheng-Zhou
authors.initials: ZZ
authors.lastname: Hou
authors.forename: Riqiang
authors.initials: R
authors.lastname: Yan
authors.forename: Feng-Yan
authors.initials: FY
authors.lastname: Sun
mesh_terms: D016229:Amyloid beta-Peptides / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002540:Cerebral Cortex / Q000378:metabolism* / Q000473:pathology; D003072:Cognition Disorders / Q000378:metabolism* / Q000473:pathology; D003704:Dementia / Q000378:metabolism* / Q000473:pathology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000473:pathology; D003929:Diabetic Neuropathies / Q000378:metabolism* / Q000473:pathology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008297:Male; D016501:Neurites / Q000378:metabolism* / Q000473:pathology; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D050050:Protein Carbonylation / Q000187:drug effects; D055503:Protein Multimerization; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D016229:Amyloid beta-Peptides; D002352:Carrier Proteins; D016877:Oxidants; C548133:RTN3 protein, rat; D006861:Hydrogen Peroxide
keywords: Aggregation; Alzheimer Disease; Axon; Central Dystrophic Neurite; Dementia; Diabetes; Dystrophin; Oxidative Stress; Reticulon