1
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Atagi Y, Onogi A, Kinukawa M, Ogino A, Kurogi K, Uchiyama K, Yasumori T, Adachi K, Togashi K, Iwata H. Genetic analysis of semen production traits of Japanese Black and Holstein bulls: genome-wide marker-based estimation of genetic parameters and environmental effect trends1. J Anim Sci 2017; 95:1900-1912. [DOI: 10.2527/jas.2016.1186] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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2
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Zhong L, Chen XF, Wang T, Wang Z, Liao C, Wang Z, Huang R, Wang D, Li X, Wu L, Jia L, Zheng H, Painter M, Atagi Y, Liu CC, Zhang YW, Fryer JD, Xu H, Bu G. Soluble TREM2 induces inflammatory responses and enhances microglial survival. J Exp Med 2017; 214:597-607. [PMID: 28209725 PMCID: PMC5339672 DOI: 10.1084/jem.20160844] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 10/25/2016] [Accepted: 01/24/2017] [Indexed: 12/31/2022] Open
Abstract
Zhong et al. describe two novel roles for soluble TREM2 (sTREM2) in regulation of proinflammatory responses and prevention of cellular apoptosis in microglia. Triggering receptor expressed on myeloid cells 2 (TREM2) is an innate immune receptor expressed in microglia in the brain. A soluble form of TREM2 (sTREM2) derived from proteolytic cleavage of the cell surface receptor is increased in the preclinical stages of AD and positively correlates with the amounts of total and phosphorylated tau in the cerebrospinal fluid. However, the physiological and pathological functions of sTREM2 remain unknown. Here, we show that sTREM2 promotes microglial survival in a PI3K/Akt-dependent manner and stimulates the production of inflammatory cytokines depending on NF-κB. Variants of sTREM2 carrying AD risk-associated mutations were less potent in both suppressing apoptosis and triggering inflammatory responses. Importantly, sTREM2 delivered to the hippocampi of both wild-type and Trem2-knockout mice elevated the expression of inflammatory cytokines and induced morphological changes of microglia. Collectively, these data indicate that sTREM2 triggers microglial activation inducing inflammatory responses and promoting survival. This study has implications for the pathogenesis of AD and provides insights into targeting sTREM2 pathway for AD therapy.
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Affiliation(s)
- Li Zhong
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Xiao-Fen Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China .,Shenzhen Research Institute of Xiamen University, Shenzhen 518063, China
| | - Tingting Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Zhe Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Chunyan Liao
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Zongqi Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Ruizhi Huang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Daxin Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Xinxiu Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Linbei Wu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Lin Jia
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Honghua Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Meghan Painter
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224
| | - Yuka Atagi
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - John D Fryer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224.,Neurobiology of Disease Graduate Program, Mayo Clinic, Jacksonville, FL 32224
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China.,Neuroscience and Aging Research Center, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China .,Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224.,Neurobiology of Disease Graduate Program, Mayo Clinic, Jacksonville, FL 32224
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3
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Atagi Y, Onogi A, Kinukawa M, Ogino A, Kurogi K, Uchiyama K, Yasumori T, Adachi K, Togashi K, Iwata H. Genetic analysis of semen production traits of Japanese Black and Holstein bulls: genome-wide marker-based estimation of genetic parameters and environmental effect trends. J Anim Sci 2017. [DOI: 10.2527/jas2016.1186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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4
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Yang L, Liu CC, Zheng H, Kanekiyo T, Atagi Y, Jia L, Wang D, N'songo A, Can D, Xu H, Chen XF, Bu G. LRP1 modulates the microglial immune response via regulation of JNK and NF-κB signaling pathways. J Neuroinflammation 2016; 13:304. [PMID: 27931217 PMCID: PMC5146875 DOI: 10.1186/s12974-016-0772-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 12/02/2016] [Indexed: 01/07/2023] Open
Abstract
Background Neuroinflammation is characterized by microglial activation and the increased levels of cytokines and chemokines in the central nervous system (CNS). Recent evidence has implicated both beneficial and toxic roles of microglia when over-activated upon nerve injury or in neurodegenerative diseases, including Alzheimer’s disease (AD). The low-density lipoprotein receptor-related protein 1 (LRP1) is a major receptor for apolipoprotein E (apoE) and amyloid-β (Aβ), which play critical roles in AD pathogenesis. LRP1 regulates inflammatory responses in peripheral tissues by modulating the release of inflammatory cytokines and phagocytosis. However, the roles of LRP1 in brain innate immunity and neuroinflammation remain unclear. Methods In this study, we determined whether LRP1 modulates microglial activation by knocking down Lrp1 in mouse primary microglia. LRP1-related functions in microglia were also assessed in the presence of LRP1 antagonist, the receptor-associated protein (RAP). The effects on the production of inflammatory cytokines were measured by quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Potential involvement of specific signaling pathways in LRP1-regulated functions including mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) were assessed using specific inhibitors. Results We found that knocking down of Lrp1 in mouse primary microglia led to the activation of both c-Jun N-terminal kinase (JNK) and NF-κB pathways with corresponding enhanced sensitivity to lipopolysaccharide (LPS) in the production of pro-inflammatory cytokines. Similar effects were observed when microglia were treated with LRP1 antagonist RAP. In addition, treatment with pro-inflammatory stimuli suppressed Lrp1 expression in microglia. Interestingly, NF-κB inhibitor not only suppressed the production of cytokines induced by the knockdown of Lrp1 but also restored the down-regulated expression of Lrp1 by LPS. Conclusions Our study uncovers that LRP1 suppresses microglial activation by modulating JNK and NF-κB signaling pathways. Given that dysregulation of LRP1 has been associated with AD pathogenesis, our work reveals a critical regulatory mechanism of microglial activation by LRP1 that could be associated with other AD-related pathways thus further nominating LRP1 as a potential disease-modifying target for the treatment of AD.
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Affiliation(s)
- Longyu Yang
- Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Medical College, Xiamen University, Xiamen, 361102, China
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL32224, USA
| | - Honghua Zheng
- Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Medical College, Xiamen University, Xiamen, 361102, China
| | - Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL32224, USA
| | - Yuka Atagi
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL32224, USA
| | - Lin Jia
- Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Medical College, Xiamen University, Xiamen, 361102, China
| | - Daxin Wang
- Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Medical College, Xiamen University, Xiamen, 361102, China
| | - Aurelie N'songo
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL32224, USA
| | - Dan Can
- Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Medical College, Xiamen University, Xiamen, 361102, China
| | - Huaxi Xu
- Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Medical College, Xiamen University, Xiamen, 361102, China
| | - Xiao-Fen Chen
- Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Medical College, Xiamen University, Xiamen, 361102, China. .,Shenzhen Research Institute of Xiamen University, Shenzhen, 518063, China.
| | - Guojun Bu
- Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Medical College, Xiamen University, Xiamen, 361102, China. .,Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL32224, USA.
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5
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Shinohara M, Murray ME, Frank RD, Shinohara M, DeTure M, Yamazaki Y, Tachibana M, Atagi Y, Davis MD, Liu CC, Zhao N, Painter MM, Petersen RC, Fryer JD, Crook JE, Dickson DW, Bu G, Kanekiyo T. Impact of sex and APOE4 on cerebral amyloid angiopathy in Alzheimer's disease. Acta Neuropathol 2016; 132:225-234. [PMID: 27179972 DOI: 10.1007/s00401-016-1580-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/06/2016] [Accepted: 05/06/2016] [Indexed: 12/26/2022]
Abstract
Cerebral amyloid angiopathy (CAA) often coexists with Alzheimer's disease (AD). APOE4 is a strong genetic risk factor for both AD and CAA. Sex-dependent differences have been shown in AD as well as in cerebrovascular diseases. Therefore, we examined the effects of APOE4, sex, and pathological components on CAA in AD subjects. A total of 428 autopsied brain samples from pathologically confirmed AD cases were analyzed. CAA severity was histologically scored in inferior parietal, middle frontal, motor, superior temporal and visual cortexes. In addition, subgroups with severe CAA (n = 60) or without CAA (n = 39) were subjected to biochemical analysis of amyloid-β (Aβ) and apolipoprotein E (apoE) by ELISA in the temporal cortex. After adjusting for age, Braak neurofibrillary tangle stage and Thal amyloid phase, we found that overall CAA scores were higher in males than females. Furthermore, carrying one or more APOE4 alleles was associated with higher overall CAA scores. Biochemical analysis revealed that the levels of detergent-soluble and detergent-insoluble Aβ40, and insoluble apoE were significantly elevated in individuals with severe CAA or APOE4. The ratio of Aβ40/Aβ42 in insoluble fractions was also increased in the presence of CAA or APOE4, although it was negatively associated with male sex. Levels of insoluble Aβ40 were positively associated with those of insoluble apoE, which were strongly influenced by CAA status. Pertaining to insoluble Aβ42, the levels of apoE correlated regardless of CAA status. Our results indicate that sex and APOE genotypes differentially influence the presence and severity of CAA in AD, likely by affecting interaction and aggregation of Aβ40 and apoE.
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Fu Y, Zhao J, Atagi Y, Nielsen HM, Liu CC, Zheng H, Shinohara M, Kanekiyo T, Bu G. Apolipoprotein E lipoprotein particles inhibit amyloid-β uptake through cell surface heparan sulphate proteoglycan. Mol Neurodegener 2016; 11:37. [PMID: 27151330 PMCID: PMC4857252 DOI: 10.1186/s13024-016-0099-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 04/19/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The accumulation, aggregation and deposition of amyloid-β (Aβ) peptides in the brain are central to the pathogenesis of Alzheimer's disease (AD). Alzheimer's disease risk increases significantly in individuals carrying one or two copies of APOE ε4 allele compared to individuals with an ε3/ε3 genotype. Growing evidence has demonstrated that apolipoprotein E (apoE) strongly influences AD pathogenesis by controlling Aβ aggregation and metabolism. Heparan sulphate proteoglycans (HSPGs) are abundant cell surface molecules that bind to both apoE and Aβ. HSPGs have been associated with Aβ aggregation and deposition. Although several lines of research have shown that apoE influences Aβ clearance in the brain, it is not clear how apoE influences HSPG-mediated cellular uptake of Aβ. RESULTS In this study, we show that apoE lipoprotein particles from conditioned media of immortalized astrocytes isolated from human APOE-targeted replacement (TR) mice significantly suppress cellular Aβ42 and Aβ40 uptake through cell surface HSPG. ApoE3 and apoE4 particles have similar binding affinity to heparin, while apoE4 particles are likely hypolipidated compared to apoE particles. We also found that the apoE particles antagonize Aβ binding to cell surface, and inhibited Aβ uptake in a concentration-dependent manner in Chinese hamster ovary (CHO) cells. While the effect was not apoE isoform-dependent, the suppressive effect of apoE particles on Aβ uptake was not observed in HSPG-deficient CHO cells. We further demonstrated that apoE particles reduced the internalization of Aβ in mouse primary neurons, an effect that is eliminated by the presence of heparin. CONCLUSIONS Taken together, our findings indicate that apoE particles irrespective of isoform inhibit HSPG-dependent cellular Aβ uptake. Modulating the ability of apoE particles to affect Aβ cellular uptake may hold promises for developing new strategies for AD therapy.
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Affiliation(s)
- Yuan Fu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
- Department of Neurology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Jing Zhao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yuka Atagi
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | | | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Honghua Zheng
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | | | | | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China.
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Zheng H, Liu CC, Atagi Y, Chen XF, Jia L, Yang L, He W, Zhang X, Kang SS, Rosenberry TL, Fryer JD, Zhang YW, Xu H, Bu G. Opposing roles of the triggering receptor expressed on myeloid cells 2 and triggering receptor expressed on myeloid cells-like transcript 2 in microglia activation. Neurobiol Aging 2016; 42:132-41. [PMID: 27143430 DOI: 10.1016/j.neurobiolaging.2016.03.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 02/14/2016] [Accepted: 03/06/2016] [Indexed: 01/12/2023]
Abstract
Mutations in triggering receptor expressed on myeloid cells 2 (TREM2), which has been proposed to regulate the inflammatory responses and the clearance of apoptotic neurons and/or amyloid-β, are genetically linked to increased risk for late-onset Alzheimer's disease (AD). Interestingly, a missense variant in TREM-like transcript 2 (TREML2), a structurally similar protein encoded by the same gene cluster with TREM2 on chromosome 6, has been shown to protect against AD. However, the molecular mechanisms by which TREM2 and TREML2 regulate the pathogenesis of AD, and their functional relationship, if any, remain unclear. Here, we show that lipopolysaccharide (LPS) stimulation significantly suppressed TREM2 but increased TREML2 expression in mouse brain. Consistent with this in vivo result, LPS or oligomeric amyloid-β treatment down regulated TREM2 but up-regulated TREML2 expression in primary microglia. Most important, modulation of TREM2 or TREML2 levels had opposing effects on inflammatory responses with enhancement or suppression of LPS-induced proinflammatory cytokine gene expression observed on TREM2 or TREML2 down regulation, respectively. In addition, the proliferation of primary microglia was significantly decreased when TREM2 was down regulated, whereas it was increased on TREML2 knockdown. Together, our results suggest that several microglial functions are strictly regulated by TREM2 and TREML2, whose dysfunctions likely contribute to AD pathogenesis by impairing brain innate immunity. Our findings provide novel mechanistic insights into the functions of TREM2 and TREML2 in microglia and have implications on designing new therapeutic strategies to treat AD.
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Affiliation(s)
- Honghua Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, PR China
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yuka Atagi
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Xiao-Fen Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, PR China
| | - Lin Jia
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, PR China
| | - Longyu Yang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, PR China
| | - Wencan He
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, PR China
| | - Xilin Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, PR China
| | - Silvia S Kang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | | | - John D Fryer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA; Neurobiology of Disease Graduate Program, Mayo Clinic, Jacksonville, FL, USA
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, PR China; Degenerative Disease Research Program, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, PR China; Degenerative Disease Research Program, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, PR China; Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA; Neurobiology of Disease Graduate Program, Mayo Clinic, Jacksonville, FL, USA.
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8
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Atagi Y, Liu CC, Painter MM, Chen XF, Verbeeck C, Zheng H, Li X, Rademakers R, Kang SS, Xu H, Younkin S, Das P, Fryer JD, Bu G. Apolipoprotein E Is a Ligand for Triggering Receptor Expressed on Myeloid Cells 2 (TREM2). J Biol Chem 2015; 290:26043-50. [PMID: 26374899 DOI: 10.1074/jbc.m115.679043] [Citation(s) in RCA: 346] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Indexed: 11/06/2022] Open
Abstract
Several heterozygous missense mutations in the triggering receptor expressed on myeloid cells 2 (TREM2) have recently been linked to risk for a number of neurological disorders including Alzheimer disease (AD), Parkinson disease, and frontotemporal dementia. These discoveries have re-ignited interest in the role of neuroinflammation in the pathogenesis of neurodegenerative diseases. TREM2 is highly expressed in microglia, the resident immune cells of the central nervous system. Along with its adaptor protein, DAP12, TREM2 regulates inflammatory cytokine release and phagocytosis of apoptotic neurons. Here, we report apolipoprotein E (apoE) as a novel ligand for TREM2. Using a biochemical assay, we demonstrated high-affinity binding of apoE to human TREM2. The functional significance of this binding was highlighted by increased phagocytosis of apoE-bound apoptotic N2a cells by primary microglia in a manner that depends on TREM2 expression. Moreover, when the AD-associated TREM2-R47H mutant was used in biochemical assays, apoE binding was vastly reduced. Our data demonstrate that apoE-TREM2 interaction in microglia plays critical roles in modulating phagocytosis of apoE-bound apoptotic neurons and establish a critical link between two proteins whose genes are strongly linked to the risk for AD.
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Affiliation(s)
| | - Chia-Chen Liu
- From the Department of Neuroscience and the Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | | | - Xiao-Fen Chen
- the Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | | | - Honghua Zheng
- the Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Xia Li
- From the Department of Neuroscience and
| | | | | | - Huaxi Xu
- the Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | | | | | - John D Fryer
- From the Department of Neuroscience and the Neurobiology of Disease Graduate Program, Mayo Clinic, Jacksonville, Florida 32224 and
| | - Guojun Bu
- From the Department of Neuroscience and the Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian 361005, China the Neurobiology of Disease Graduate Program, Mayo Clinic, Jacksonville, Florida 32224 and
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Painter MM, Atagi Y, Liu CC, Rademakers R, Xu H, Fryer JD, Bu G. TREM2 in CNS homeostasis and neurodegenerative disease. Mol Neurodegener 2015; 10:43. [PMID: 26337043 PMCID: PMC4560063 DOI: 10.1186/s13024-015-0040-9] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 08/19/2015] [Indexed: 02/07/2023] Open
Abstract
Myeloid-lineage cells accomplish a myriad of homeostatic tasks including the recognition of pathogens, regulation of the inflammatory milieu, and mediation of tissue repair and regeneration. The innate immune receptor and its adaptor protein—triggering receptor expressed on myeloid cells 2 (TREM2) and DNAX-activating protein of 12 kDa (DAP12)—possess the ability to modulate critical cellular functions via crosstalk with diverse signaling pathways. As such, mutations in TREM2 and DAP12 have been found to be associated with a range of disease phenotypes. In particular, mutations in TREM2 increase the risk for Alzheimer's disease and other neurodegenerative disorders. The leading hypothesis is that microglia, the resident immune cells of the central nervous system, are the major myeloid cells affected by dysregulated TREM2-DAP12 function. Here, we review how impaired signaling by the TREM2-DAP12 pathway leads to altered immune responses in phagocytosis, cytokine production, and microglial proliferation and survival, thus contributing to disease pathogenesis.
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Affiliation(s)
- Meghan M Painter
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| | - Yuka Atagi
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA. .,Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361102, China.
| | - Rosa Rademakers
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361102, China.
| | - John D Fryer
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA. .,Neurobiology of Disease Graduate Program, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA. .,Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361102, China. .,Neurobiology of Disease Graduate Program, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
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10
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Nielsen HM, Atagi Y, Hallström T, Fu Y, Zipfel PF, Bu G. O3‐06‐04: Apolipoprotein e affects neuronal alpha‐synuclein uptake in an isoform‐dependent manner. Alzheimers Dement 2015. [DOI: 10.1016/j.jalz.2015.07.270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
| | - Yuka Atagi
- Mayo Clinic College of MedicineJacksonvilleFLUSA
| | | | - Yuan Fu
- Mayo Clinic College of MedicineJacksonvilleFLUSA
| | | | - Guojun Bu
- Mayo Clinic College of MedicineJacksonvilleFLUSA
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11
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Casey CS, Atagi Y, Yamazaki Y, Shinohara M, Tachibana M, Fu Y, Bu G, Kanekiyo T. Apolipoprotein E Inhibits Cerebrovascular Pericyte Mobility through a RhoA Protein-mediated Pathway. J Biol Chem 2015; 290:14208-17. [PMID: 25903128 DOI: 10.1074/jbc.m114.625251] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Indexed: 12/30/2022] Open
Abstract
Pericytes play a critical role in the cerebrovasculature within the CNS. These small contractile cells produce large quantities of apolipoprotein E (apoE) whose isoforms influence cerebrovascular functions and determine the genetic risk for Alzheimer disease. Despite extensive studies on astrocyte-secreted apoE, which supports synapses by transporting cholesterol to neurons, the biochemical properties and function of apoE secreted by pericytes are not clear. Because pericytes mediate important functions in the CNS, including the initiation of glial scar formation, angiogenesis, and maintenance of the blood-brain barrier, we investigated the potential role of apoE in pericyte mobility. We found that knockdown of apoE expression significantly accelerates pericyte migration, an effect that can be rescued by exogenous apoE3, but not apoE4, a risk factor for Alzheimer disease. ApoE-regulated migration of pericytes also requires the function of the low-density lipoprotein receptor-related protein 1 (LRP1), a major apoE receptor in the brain that is abundantly expressed in pericytes. Because apoE-knockdown also leads to enhanced cell adhesion, we investigated the role of apoE in the regulation of the actin cytoskeleton. Interestingly, we found that the levels of active RhoA are increased significantly in apoE knockdown pericytes and that RhoA inhibitors blocked pericyte migration. Taken together, our results suggest that apoE has an intrinsic role in pericyte mobility, which is vital in maintaining cerebrovascular function. These findings provide novel insights into the role of apoE in the cerebrovascular system.
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Affiliation(s)
- Caroline S Casey
- From the Department of Neuroscience, Mayo Clinic, Jacksonville, Florida 32224
| | - Yuka Atagi
- From the Department of Neuroscience, Mayo Clinic, Jacksonville, Florida 32224
| | - Yu Yamazaki
- From the Department of Neuroscience, Mayo Clinic, Jacksonville, Florida 32224
| | - Mitsuru Shinohara
- From the Department of Neuroscience, Mayo Clinic, Jacksonville, Florida 32224
| | - Masaya Tachibana
- From the Department of Neuroscience, Mayo Clinic, Jacksonville, Florida 32224
| | - Yuan Fu
- From the Department of Neuroscience, Mayo Clinic, Jacksonville, Florida 32224
| | - Guojun Bu
- From the Department of Neuroscience, Mayo Clinic, Jacksonville, Florida 32224
| | - Takahisa Kanekiyo
- From the Department of Neuroscience, Mayo Clinic, Jacksonville, Florida 32224
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Martínez-Morillo E, Hansson O, Atagi Y, Bu G, Minthon L, Diamandis EP, Nielsen HM. Total apolipoprotein E levels and specific isoform composition in cerebrospinal fluid and plasma from Alzheimer's disease patients and controls. Acta Neuropathol 2014; 127:633-43. [PMID: 24633805 DOI: 10.1007/s00401-014-1266-2] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/03/2014] [Accepted: 03/04/2014] [Indexed: 11/30/2022]
Abstract
The apolipoprotein E (ApoE) ε4 allele is the strongest risk factor of sporadic Alzheimer's disease (AD), however, the fluid concentrations of ApoE and its different isoforms (ApoE2, ApoE3 and ApoE4) in AD patients and among APOE genotypes (APOE ε2, ε3, ε4) remain controversial. Using a novel mass spectrometry-based method, we quantified total ApoE and specific ApoE isoform concentrations and potential associations with age, cognitive status, cholesterol levels and established AD biomarkers in cerebrospinal fluid (CSF) from AD patients versus non-AD individuals with different APOE genotypes. We also investigated plasma total ApoE and ApoE isoform composition in a subset of these individuals. In total n = 43 AD and n = 43 non-AD subjects were included. We found that CSF and plasma total ApoE levels did not correlate with age or cognitive status and did not differ between AD and non-AD subjects deeming ApoE as an unfit diagnostic marker for AD. Also, whereas CSF ApoE levels did not vary between APOE genotypes APOE ε4 carriers exhibited significantly decreased plasma ApoE levels attributed to a specific decrease in the ApoE4 isoform concentrations. CSF total ApoE concentrations were positively associated with CSF, total tau, tau phosphorylated at Thr181 and Aβ1-42 of which the latter association was weaker and only present in APOE ε4 carriers indicating a differential involvement of ApoE in tau versus Aβ-linked neuropathological processes. Future studies need to elucidate whether the observed plasma ApoE4 deficiency is a life-long condition in APOE ɛ4 carriers and whether this decrease in plasma ApoE predisposes APOE ɛ4 carriers to AD.
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Affiliation(s)
- Eduardo Martínez-Morillo
- Lunenfeld-Tanenbaum Research Institute, Joseph and Wolf Lebovic Health Centre, Mount Sinai Hospital, Toronto, ON, Canada,
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Morfini GA, Burns M, Binder LI, Kanaan NM, LaPointe N, Bosco DA, Brown RH, Brown H, Tiwari A, Hayward L, Edgar J, Nave KA, Garberrn J, Atagi Y, Song Y, Pigino G, Brady ST. Axonal transport defects in neurodegenerative diseases. J Neurosci 2009; 29:12776-86. [PMID: 19828789 PMCID: PMC2801051 DOI: 10.1523/jneurosci.3463-09.2009] [Citation(s) in RCA: 335] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 08/04/2009] [Indexed: 12/26/2022] Open
Abstract
Adult-onset neurodegenerative diseases (AONDs) comprise a heterogeneous group of neurological disorders characterized by a progressive, age-dependent decline in neuronal function and loss of selected neuronal populations. Alterations in synaptic function and axonal connectivity represent early and critical pathogenic events in AONDs, but molecular mechanisms underlying these defects remain elusive. The large size and complex subcellular architecture of neurons render them uniquely vulnerable to alterations in axonal transport (AT). Accordingly, deficits in AT have been documented in most AONDs, suggesting a common defect acquired through different pathogenic pathways. These observations suggest that many AONDs can be categorized as dysferopathies, diseases in which alterations in AT represent a critical component in pathogenesis. Topics here address various molecular mechanisms underlying alterations in AT in several AONDs. Illumination of such mechanisms provides a framework for the development of novel therapeutic strategies aimed to prevent axonal and synaptic dysfunction in several major AONDs.
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Affiliation(s)
- Gerardo A Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Togashi K, Lin C, Atagi Y, Hagiya K, Sato J, Nakanishi T. Genetic characteristics of Japanese Holstein cows based on multiple-lactation random regression test-day animal models. Livest Sci 2008. [DOI: 10.1016/j.livsci.2007.04.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Atagi Y, Ikadai H, Kurohmaru M, Hayashi Y. Testicular disruption in the As (aspermia) mutant rat, with special reference to the aggregate of ribosomes. J Vet Med Sci 1993; 55:301-6. [PMID: 8513014 DOI: 10.1292/jvms.55.301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The morphology of the testis of the mutant As (aspermia) strain rat with severely interrupted spermatogenesis was investigated in the present study. The most advanced development in spermatogenesis was observed at the step 8 at which spermatids had basally-oriented acrosomes. Multinucleate giant cells derived from round spermatids were frequently encountered within the seminiferous tubules. The functionally normal status of the blood-testis barrier between adjacent Sertoli cells was confirmed by morphological and lanthanum tracer studies. By light microscopy, a peculiar structure was found within the pachytene spermatocyte, consisting of numerous particles of approximately 25 nm in diameter. By histochemical and electron microscopic studies, this structure was identified as an aggregate of ribosomes. Neither immature spermatogenic cells up to the pachytene phase, nor Sertoli cells nor interstitial regions showed a recognizable abnormality. It seems that the testicular disruption in the As mutant rat is due to the abnormality in the protein synthetic pathway in pachytene spermatocytes.
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Affiliation(s)
- Y Atagi
- Department of Veterinary Anatomy, Faculty of Agriculture, University of Tokyo, Japan
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Bando S, Nishimura N, Hashiguchi T, Atagi Y, Akiyama K, Nouzu N, Shinomiya H, Mori H. [A case of aortic stenosis with four types of gap phenomenon in A-V conduction]. Kokyu To Junkan 1986; 34:1349-55. [PMID: 3823648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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17
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Bando S, Hashiguchi T, Tada N, Minezono K, Nishimura N, Atagi Y, Shinomiya H, Mori H. [Electrophysiological study of conduction system in dilated cardiomyopathy]. Kokyu To Junkan 1986; 34:985-90. [PMID: 3786965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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