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Early-life Pb exposure as a potential risk factor for Alzheimer’s disease: are there hazards for the Mexican population? J Biol Inorg Chem 2019; 24:1285-1303. [DOI: 10.1007/s00775-019-01739-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/25/2019] [Indexed: 12/30/2022]
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Herring SK, Moon HJ, Rawal P, Chhibber A, Zhao L. Brain clusterin protein isoforms and mitochondrial localization. eLife 2019; 8:48255. [PMID: 31738162 PMCID: PMC6860991 DOI: 10.7554/elife.48255] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/24/2019] [Indexed: 01/04/2023] Open
Abstract
Clusterin (CLU), or apolipoprotein J (ApoJ), is the third most predominant genetic risk factor associated with late-onset Alzheimer’s disease (LOAD). In this study, we use multiple rodent and human brain tissue and neural cell models to demonstrate that CLU is expressed as multiple isoforms that have distinct cellular or subcellular localizations in the brain. Of particular significance, we identify a non-glycosylated 45 kDa CLU isoform (mitoCLU) that is localized to the mitochondrial matrix and expressed in both rodent and human neurons and astrocytes. In addition, we show that rodent mitoCLU is translated from a non-canonical CUG (Leu) start site in Exon 3, a site that coincides with an AUG (Met) in human CLU. Last, we reveal that mitoCLU is present at the gene and protein level in the currently available CLU–/– mouse model. Collectively, these data provide foundational knowledge that is integral in elucidating the relationship between CLU and the development of LOAD.
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Affiliation(s)
- Sarah K Herring
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States
| | - Hee-Jung Moon
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States
| | - Punam Rawal
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States
| | - Anindit Chhibber
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States
| | - Liqin Zhao
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States.,Neuroscience Graduate Program, University of Kansas, Lawrence, United States
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Olsen I, Singhrao SK. Is there a link between genetic defects in the complement cascade and Porphyromonas gingivalis in Alzheimer's disease? J Oral Microbiol 2019; 12:1676486. [PMID: 31893014 PMCID: PMC6818111 DOI: 10.1080/20002297.2019.1676486] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 09/17/2019] [Indexed: 12/18/2022] Open
Abstract
Defects, as determined by Genome-Wide Association Studies (GWAS), in the complement cascade of innate immunity have been suggested to play a key role in Alzheimer's disease (AD). These defective genes encode sub-component 1s (C1s), complement receptor 1, complement component 9, and clusterin, a fluid-phase regulatory protein. A dysregulated complement cascade has been shown to relate to cell activation, defective complement mediated clearance and possible cognitive decline in AD patients. Porphyromonas gingivalis, a putative keystone pathogen of periodontal disease, has been reported to be associated with human AD. The inflammatory burden following experimental oral infection in mice and putative entry of this bacterium into the brain appears to drive the formation of amyloid-beta plaques and neurofibrillary tangles with loss of cognition. P. gingivalis is a master of immune subversion in this inflammatory cascade and may establish microbial dysbiosis where it is located. Here we discuss if P. gingivalis may enhance the detrimental effects of the defective GWAS complement cascade protein genes.
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Affiliation(s)
- Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Sim K Singhrao
- Dementia and Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
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The effect of BACE1-AS on β-amyloid generation by regulating BACE1 mRNA expression. BMC Mol Biol 2019; 20:23. [PMID: 31570097 PMCID: PMC6771094 DOI: 10.1186/s12867-019-0140-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 09/19/2019] [Indexed: 02/03/2023] Open
Abstract
Background The BACE1 antisense transcript (BACE1-AS) is a conserved long noncoding RNA (lncRNA). The level of BACE1-AS is significantly increased and the level of the BACE1 mRNA is slightly increased in subjects with AD. BACE1-AS exerts a significant moderating effect on the expression of the BACE1 mRNA and promotes the formation of Aβ. After the administration of Aβ1-42 to SH-SY5Y cells and C57/BL6J mice, we detected the expression of BACE1-AS, BACE1 mRNA, and BACE1 protein, as well as the concentration of Aβ1-40. Then, we silenced the expression of BACE1-AS in SH-SY5Y and 20E2 cells using siRNAs targeting BACE1-AS and detected its effects on the levels of the BACE1 mRNA and BACE1 protein and Aβ1-40 generation. Results The administration of Aβ1-42 increased the expression of BACE1-AS, BACE1 mRNA and protein, as well as the concentration of Aβ1-40 in SH-SY5Y cells and the brains of C57BL/6J mice. Pretreatment with the BACE1-AS siRNA inhibited the effect of Aβ1-42 on increasing the expression of BACE1-AS and BACE1, as well as the generation of Aβ. Conclusions The mechanism by which exogenous Aβ1-42 induces BACE1 expression and Aβ generation is mediated by BACE1-AS. BACE1-AS is involved in the mechanism regulating BACE1 expression and Aβ generation in APPsw transgenic cells.
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Xu Y, Xu L, Han M, Liu X, Li F, Zhou X, Wang Y, Bi J. Altered mitochondrial DNA methylation and mitochondrial DNA copy number in an APP/PS1 transgenic mouse model of Alzheimer disease. Biochem Biophys Res Commun 2019; 520:41-46. [PMID: 31564416 DOI: 10.1016/j.bbrc.2019.09.094] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 09/21/2019] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is a chronic neurodegenerative disease and mitochondrial impairment is a key feature of AD. The mitochondrial DNA (mtDNA) epigenetic mechanism is a relatively new field compared to nuclear DNA. The relationship between mtDNA epigenetic mechanism and AD hasn't been established. So we analyzed the mtDNA methylation in D-loop region and 12 S rRNA gene in the hippocampi in amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice by bisulfite pyrosequencing. Mitochondrial DNA copy number and gene expression were studied by quantitative real-time PCR (qRT-PCR). We observed a decrease in the displacement loop (D-loop) methylation and an increase in 12 S rRNA gene methylation, while both the mtDNA copy number and the mitochondrial gene expression were reduced in APP/PS1 transgenic mice. In summary, the present finding suggest that mtDNA methylation may play a role in AD pathology, which warrants larger future investigations.
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Affiliation(s)
- YingYing Xu
- Department of Neurology Medicine, Second Hospital of Shandong University, Jinan, 250033, China
| | - LinLin Xu
- Department of Neurology Medicine, Second Hospital of Shandong University, Jinan, 250033, China
| | - Min Han
- Department of Neurology Medicine, Second Hospital of Shandong University, Jinan, 250033, China
| | - XiangTian Liu
- Department of Neurology Medicine, Second Hospital of Shandong University, Jinan, 250033, China
| | - Fan Li
- Department of Neurology Medicine, Second Hospital of Shandong University, Jinan, 250033, China
| | - XiaoYan Zhou
- Department of Neurology Medicine, Second Hospital of Shandong University, Jinan, 250033, China
| | - Yun Wang
- Department of Neurology Medicine, Second Hospital of Shandong University, Jinan, 250033, China.
| | - JianZhong Bi
- Department of Neurology Medicine, Second Hospital of Shandong University, Jinan, 250033, China
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Chen S, Zhou M, Sun J, Guo A, Fernando RL, Chen Y, Peng P, Zhao G, Deng Y. DPP-4 inhibitor improves learning and memory deficits and AD-like neurodegeneration by modulating the GLP-1 signaling. Neuropharmacology 2019; 157:107668. [PMID: 31199957 DOI: 10.1016/j.neuropharm.2019.107668] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 05/31/2019] [Accepted: 06/10/2019] [Indexed: 02/06/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) signaling in the brain plays an important role in the regulation of glucose metabolism, which is impaired in Alzheimer's disease (AD). Here, we detected the GLP-1 and GLP-1 receptor (GLP-1R) in AD human brain and APP/PS1/Tau transgenic (3xTg) mice brain, finding that they were both decreased in AD human and mice brain. Enhanced GLP-1 exerts its protective effects on AD, however, this is rapidly degraded into inactivated metabolites by dipeptidyl peptidase-4 (DPP-4), resulting in its extremely short half-time. DPP-4 inhibitors, thus, was applied to improve the level of GLP-1 and GLP-1R expression in the hippocampus and cortex of AD mice brains. It is also protected learning and memory and synaptic proteins, increased the O-Glycosylation and decreased abnormal phosphorylation of tau and neurofilaments (NFs), degraded intercellular β-amyloid (Aβ) accumulation and alleviated neurodegeneration related to GLP-1 signaling pathway.
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Affiliation(s)
- Shuyi Chen
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Mei Zhou
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Jie Sun
- Department of Pathology, Tianjin People's Hospital, Tianjin, China
| | - Ai Guo
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Roger Lakmal Fernando
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Yanlin Chen
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Peng Peng
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Gang Zhao
- Department of Pathology, Tianjin Tumor Hospital, Tianjin Medical University, Tianjin, China
| | - Yanqiu Deng
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.
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Coppedè F, Stoccoro A. Mitoepigenetics and Neurodegenerative Diseases. Front Endocrinol (Lausanne) 2019; 10:86. [PMID: 30837953 PMCID: PMC6389613 DOI: 10.3389/fendo.2019.00086] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 01/31/2019] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial impairment and increased oxidative stress are common features in neurodegenerative disorders, leading researchers to speculate that epigenetic changes in the mitochondrial DNA (mitoepigenetics) could contribute to neurodegeneration. The few studies performed so far to address this issue revealed impaired methylation levels of the mitochondrial regulatory region (D-loop region) in both animal models, postmortem brain regions, or circulating blood cells of patients with Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Those studies also revealed that mtDNA D-loop methylation levels are subjected to a dynamic regulation within the progression of the neurodegenerative process, could be affected by certain neurodegenerative disease-causative mutations, and are inversely correlated with the mtDNA copy number. The methylation levels of other mtDNA regions than the D-loop have been scarcely investigated in human specimens from patients with neurodegenerative disorders or in animal models of the disease, and evidence of impaired methylation levels is often limited to a single study, making it difficult to clarify their correlation with mitochondrial dynamics and gene expression levels in these disorders. Overall, the preliminary results of the studies performed so far are encouraging making mitoepigenetics a timely and attractive field of investigation, but additional research is warranted to clarify the connections among epigenetic changes occurring in the mitochondrial genome, mitochondrial DNA dynamics and gene expression, and the neurodegenerative process.
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