1
|
Guan PP, Ge TQ, Wang P. As a Potential Therapeutic Target, C1q Induces Synapse Loss Via Inflammasome-activating Apoptotic and Mitochondria Impairment Mechanisms in Alzheimer's Disease. J Neuroimmune Pharmacol 2023; 18:267-284. [PMID: 37386257 DOI: 10.1007/s11481-023-10076-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 06/16/2023] [Indexed: 07/01/2023]
Abstract
C1q, the initiator of the classical pathway of the complement system, is activated during Alzheimer's disease (AD) development and progression and is especially associated with the production and deposition of β-amyloid protein (Aβ) and phosphorylated tau in β-amyloid plaques (APs) and neurofibrillary tangles (NFTs). Activation of C1q is responsible for induction of synapse loss, leading to neurodegeneration in AD. Mechanistically, C1q could activate glial cells, which results in the loss of synapses via regulation of synapse pruning and phagocytosis in AD. In addition, C1q induces neuroinflammation by inducing proinflammatory cytokine secretion, which is partially mediated by inflammasome activation. Activation of inflammasomes might mediate the effects of C1q on induction of synapse apoptosis. On the other hand, activation of C1q impairs mitochondria, which hinders the renovation and regeneration of synapses. All these actions of C1q contribute to the loss of synapses during neurodegeneration in AD. Therefore, pharmacological, or genetic interventions targeting C1q may provide potential therapeutic strategies for combating AD.
Collapse
Affiliation(s)
- Pei-Pei Guan
- College of Life and Health Sciences, Northeastern University, 110819, Shenyang, People's Republic of China
| | - Tong-Qi Ge
- College of Life and Health Sciences, Northeastern University, 110819, Shenyang, People's Republic of China
| | - Pu Wang
- College of Life and Health Sciences, Northeastern University, 110819, Shenyang, People's Republic of China.
| |
Collapse
|
2
|
Jury-Garfe N, You Y, Martínez P, Redding-Ochoa J, Karahan H, Johnson TS, Zhang J, Kim J, Troncoso JC, Lasagna-Reeves CA. Enhanced microglial dynamics and paucity of tau seeding in the amyloid plaque microenvironment contributes to cognitive resilience in Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.27.550884. [PMID: 37546928 PMCID: PMC10402121 DOI: 10.1101/2023.07.27.550884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Asymptomatic Alzheimer's disease (AsymAD) describes the status of subjects with preserved cognition but with identifiable Alzheimer's disease (AD) brain pathology (i.e. Aβ-amyloid deposits, neuritic plaques, and neurofibrillary tangles) at autopsy. In this study, we investigated the postmortem brains of a cohort of AsymAD cases to gain insight into the underlying mechanisms of resilience to AD pathology and cognitive decline. Our results showed that AsymAD cases exhibit an enrichment of core plaques and decreased filamentous plaque accumulation, as well as an increase in microglia surrounding this last type. In AsymAD cases we found less pathological tau aggregation in dystrophic neurites compared to AD and tau seeding activity comparable to healthy control subjects. We used spatial transcriptomics to further characterize the plaque niche and found autophagy, endocytosis, and phagocytosis within the top upregulated pathways in the AsymAD plaque niche, but not in AD. Furthermore, we found ARP2, an actin-based motility protein crucial to initiate the formation of new actin filaments, increased within microglia in the proximity of amyloid plaques in AsymAD. Our findings support that the amyloid-plaque microenvironment in AsymAD cases is characterized by microglia with highly efficient actin-based cell motility mechanisms and decreased tau seeding compared to AD. These two mechanisms can potentially provide protection against the toxic cascade initiated by Aβ that preserves brain health and slows down the progression of AD pathology.
Collapse
Affiliation(s)
- Nur Jury-Garfe
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yanwen You
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Pablo Martínez
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Javier Redding-Ochoa
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Hande Karahan
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, USA
| | - Travis S. Johnson
- Department of Biostatistics and Health Data Science, Indiana University School of Medicine, Indianapolis, USA
| | - Jie Zhang
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, USA
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jungsu Kim
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, USA
| | - Juan C. Troncoso
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Cristian A. Lasagna-Reeves
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA
| |
Collapse
|
3
|
Veteleanu A, Stevenson-Hoare J, Keat S, Daskoulidou N, Zetterberg H, Heslegrave A, Escott-Price V, Williams J, Sims R, Zelek WM, Carpanini SM, Morgan BP. Alzheimer's disease-associated complement gene variants influence plasma complement protein levels. J Neuroinflammation 2023; 20:169. [PMID: 37480051 PMCID: PMC10362776 DOI: 10.1186/s12974-023-02850-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/08/2023] [Indexed: 07/23/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) has been associated with immune dysregulation in biomarker and genome-wide association studies (GWAS). GWAS hits include the genes encoding complement regulators clusterin (CLU) and complement receptor 1 (CR1), recognised as key players in AD pathology, and complement proteins have been proposed as biomarkers. MAIN BODY To address whether changes in plasma complement protein levels in AD relate to AD-associated complement gene variants we first measured relevant plasma complement proteins (clusterin, C1q, C1s, CR1, factor H) in a large cohort comprising early onset AD (EOAD; n = 912), late onset AD (LOAD; n = 492) and control (n = 504) donors. Clusterin and C1q were significantly increased (p < 0.001) and sCR1 and factor H reduced (p < 0.01) in AD plasma versus controls. ROC analyses were performed to assess utility of the measured complement biomarkers, alone or in combination with amyloid beta, in predicting AD. C1q was the most predictive single complement biomarker (AUC 0.655 LOAD, 0.601 EOAD); combining C1q with other complement or neurodegeneration makers through stepAIC-informed models improved predictive values slightly. Effects of GWS SNPs (rs6656401, rs6691117 in CR1; rs11136000, rs9331888 in CLU; rs3919533 in C1S) on protein concentrations were assessed by comparing protein levels in carriers of the minor vs major allele. To identify new associations between SNPs and changes in plasma protein levels, we performed a GWAS combining genotyping data in the cohort with complement protein levels as endophenotype. SNPs in CR1 (rs6656401), C1S (rs3919533) and CFH (rs6664877) reached significance and influenced plasma levels of the corresponding protein, whereas SNPs in CLU did not influence clusterin levels. CONCLUSION Complement dysregulation is evident in AD and may contribute to pathology. AD-associated SNPs in CR1, C1S and CFH impact plasma levels of the encoded proteins, suggesting a mechanism for impact on disease risk.
Collapse
Affiliation(s)
- Aurora Veteleanu
- UK Dementia Research Institute Cardiff, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
| | | | - Samuel Keat
- UK Dementia Research Institute Cardiff, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
| | - Nikoleta Daskoulidou
- UK Dementia Research Institute Cardiff, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
| | - Henrik Zetterberg
- UK Dementia Research Institute at University College London, London, WC1E6BT UK
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Psychology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N3BG UK
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China
| | - Amanda Heslegrave
- UK Dementia Research Institute at University College London, London, WC1E6BT UK
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N3BG UK
| | | | - Julie Williams
- UK Dementia Research Institute Cardiff, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
| | - Rebecca Sims
- Division of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, CF244HQ UK
| | - Wioleta M. Zelek
- UK Dementia Research Institute Cardiff, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
| | - Sarah M. Carpanini
- UK Dementia Research Institute Cardiff, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
| | - Bryan Paul Morgan
- UK Dementia Research Institute Cardiff, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
| |
Collapse
|
4
|
Zhang W, Ding L, Zhang M, Zheng S, Ma R, Gong J, Mao H, Xu H, Xu P, Zhang Y. Dietary intake of α-ketoglutarate ameliorates α-synuclein pathology in mouse models of Parkinson's disease. Cell Mol Life Sci 2023; 80:155. [PMID: 37204481 PMCID: PMC11073026 DOI: 10.1007/s00018-023-04807-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 05/09/2023] [Accepted: 05/10/2023] [Indexed: 05/20/2023]
Abstract
Parkinson's disease (PD) is a progressive movement disorder characterized by dopaminergic (DA) neuron degeneration and the existence of Lewy bodies formed by misfolded α-synuclein. Emerging evidence supports the benefits of dietary interventions in PD due to their safety and practicality. Previously, dietary intake of α-ketoglutarate (AKG) was proved to extend the lifespan of various species and protect mice from frailty. However, the mechanism of dietary AKG's effects in PD remains undetermined. In the present study, we report that an AKG-based diet significantly ameliorated α-synuclein pathology, and rescued DA neuron degeneration and impaired DA synapses in adeno-associated virus (AAV)-loaded human α-synuclein mice and transgenic A53T α-synuclein (A53T α-Syn) mice. Moreover, AKG diet increased nigral docosahexaenoic acid (DHA) levels and DHA supplementation reproduced the anti-α-synuclein effects in the PD mouse model. Our study reveals that AKG and DHA induced microglia to phagocytose and degrade α-synuclein via promoting C1q and suppressed pro-inflammatory reactions. Furthermore, results indicate that modulating gut polyunsaturated fatty acid metabolism and microbiota Lachnospiraceae_NK4A136_group in the gut-brain axis may underlie AKG's benefits in treating α-synucleinopathy in mice. Together, our findings propose that dietary intake of AKG is a feasible and promising therapeutic approach for PD.
Collapse
Affiliation(s)
- Wenlong Zhang
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, China
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
| | - Liuyan Ding
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, China
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
| | - Mengran Zhang
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
- School of Life Sciences, Westlake University, Hangzhou, 310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, 310024, China
| | - Shaohui Zheng
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
- School of Life Sciences, Westlake University, Hangzhou, 310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, 310024, China
| | - Runfang Ma
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
- School of Life Sciences, Westlake University, Hangzhou, 310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, 310024, China
| | - Junwei Gong
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
| | - Hengxu Mao
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, China
| | - Huaxi Xu
- Institute for Brain Science and Disease, Chongqing Medical University, Chongqing, 400016, China
| | - Pingyi Xu
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, China.
| | - Yunlong Zhang
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China.
- School of Life Sciences, Westlake University, Hangzhou, 310024, China.
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, 310024, China.
| |
Collapse
|
5
|
Lin C, Xu C, Zhou Y, Chen A, Jin B. Identification of Biomarkers Related to M2 Macrophage Infiltration in Alzheimer’s Disease. Cells 2022; 11:cells11152365. [PMID: 35954209 PMCID: PMC9367736 DOI: 10.3390/cells11152365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 02/01/2023] Open
Abstract
Many studies have demonstrated that neuroinflammation contributes to the onset and development of Alzheimer’s disease (AD). The infiltration of immune cells in the brain was observed in AD. The purpose of the present study was to verify potential mechanisms and screen out biomarkers related to immune infiltration in AD. We collected the expression profiling datasets of AD patients and healthy donors from the NCBI’s Gene Expression Omnibus (GEO) database. We confirmed that immune-related mechanisms were involved in AD using differentially expressed genes analysis and functional enrichment analysis. We then found that M2 macrophage infiltration was most positively correlated with AD according to the CIBERSORT algorithm and a weighted gene co-expression network analysis (WGCNA). TLR2, FCGR2A, ITGB2, NCKAP1L and CYBA were identified as hub genes correlated with M2 macrophage infiltration in AD. Furthermore, the expression levels of these hub genes were positively correlated with Aβ42 and β-secretase activity. A diagnostic model of these hub genes was constructed, which showed a high area under the curve (AUC) value in both the derivation and validation cohorts. Overall, our work further expanded our understanding of the immunological mechanisms of AD and provided new insights into therapeutic strategies in AD.
Collapse
Affiliation(s)
- Caixiu Lin
- The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China; (C.L.); (C.X.)
- Department of Neurology, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China;
| | - Congcong Xu
- The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China; (C.L.); (C.X.)
| | - Yongji Zhou
- Department of Neurology, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China;
| | - Anqi Chen
- The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China;
| | - Baiye Jin
- The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China; (C.L.); (C.X.)
- Correspondence:
| |
Collapse
|
6
|
Yuan T, Orock A, Greenwood-VanMeerveld B. An enriched environment reduces chronic stress-induced visceral pain through modulating microglial activity in the central nucleus of the amygdala. Am J Physiol Gastrointest Liver Physiol 2022; 322:G223-G233. [PMID: 34877892 PMCID: PMC8793868 DOI: 10.1152/ajpgi.00307.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cognitive behavioral therapy (CBT) improves the quality of life for patients with brain-gut disorders; however, the underlying mechanisms of CBT remain to be explored. Previously, we showed that environmental enrichment (EE), an experimental paradigm that mirrors positive behavioral intervention, ameliorates chronic stress-induced visceral hypersensitivity in a rodent model via mechanisms involving altered activity in the central nucleus of amygdala (CeA). In the present study, we investigated whether microglia-mediated synaptic plasticity in the CeA is a potential mechanism underlying the protective effects of EE against stress-induced visceral hypersensitivity. We stereotaxically implanted corticosterone (CORT) micropellets onto the dorsal margin of the CeA shown previously to induce colonic hypersensitivity. Animals were housed in EE cages or standard cages for 14 days after CORT implantation. Visceral sensitivity was assessed via visceromotor behavioral response to colorectal distension. Microglial morphology, microglia-mediated synaptic engulfment, and the expression of synaptic pruning-related signals complement component 1q (C1q), complement component 3 (C3), and C3 receptor (C3R) were measured using immunofluorescence and RNAscope assay. We found that housing CORT implanted rats in EE cages for 14 days attenuated visceral hypersensitivity in both male and female rats as compared with control rats maintained in standard housing. EE reduced CORT-induced microglial remodeling and microglia-mediated synaptic pruning with reduced C1q and CR3, but not C3, expression. Our data suggest that exposure to EE is sufficient to ameliorate stress-induced visceral pain via reducing amygdala microglia-modulated neuronal plasticity.NEW & NOTEWORTHY Clinical studies show that cognitive behavioral therapy (CBT) is effective in ameliorating visceral pain in patient with irritable bowel syndrome (IBS), yet the underlying mechanisms remain unexplored. By using environmental enrichment (EE), an experimental paradigm that mirrors positive behavioral intervention, we demonstrated that microglia-mediated synaptic plasticity in the CeA explains, plays a role, at least in part, in the positive effects of EE to reduce visceral hypersensitivity.
Collapse
Affiliation(s)
- Tian Yuan
- 1Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Albert Orock
- 1Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Beverley Greenwood-VanMeerveld
- 1Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma
| |
Collapse
|
7
|
Ma Y, Ding X, Shao M, Qiu Y, Li S, Cao W, Xu G. Association of Serum Complement C1q and C3 Level with Age-Related Macular Degeneration in Women. J Inflamm Res 2022; 15:285-294. [PMID: 35058703 PMCID: PMC8765539 DOI: 10.2147/jir.s348539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/25/2021] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To investigate the association between serum complement components and age-related macular degeneration (AMD). PATIENTS AND METHODS A total of 118 AMD patients and age- and sex-matched 106 control subjects were included. Demographic data and the level of serum complement component (C)1q, C3 and C4 were evaluated. Based on sex, the subjects were stratified into male and female subgroups. RESULTS The level of C1q (226.31±45.33mg/dL) was significantly higher and C3 (121.14±15.76mg/dL) was significantly lower than that in control group (200.03±38.54mg/dL) (128.42±19.81mg/dL) in the female AMD patients (p = 0.005, p = 0.045). Logistic regression showed that increased C1q (OR = 1.132, p = 0.016) and decreased C3 (OR = 0.960, p = 0.048) were independent risk factors for female AMD patients. No statistical significance was observed in the male. CONCLUSION Increased C1q and decreased C3 were associated with increased risk of AMD, suggesting that the complement classical pathway probably be involved in AMD, especially in female.
Collapse
Affiliation(s)
- Yingbo Ma
- Department of Clinical Laboratory, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Xueqing Ding
- Department of Clinical Laboratory, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Mingxi Shao
- Department of Clinical Laboratory, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Yichao Qiu
- Department of Clinical Laboratory, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Shengjie Li
- Department of Clinical Laboratory, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Wenjun Cao
- Department of Clinical Laboratory, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Gezhi Xu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, People's Republic of China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, People's Republic of China
| |
Collapse
|
8
|
Complement System in Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms222413647. [PMID: 34948444 PMCID: PMC8705098 DOI: 10.3390/ijms222413647] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 12/10/2021] [Accepted: 12/15/2021] [Indexed: 01/02/2023] Open
Abstract
Alzheimer’s disease is a type of dementia characterized by problems with short-term memory, cognition, and difficulties with activities of daily living. It is a progressive, neurodegenerative disorder. The complement system is an ancient part of the innate immune system and comprises of more than thirty serum and membrane-bound proteins. This system has three different activating pathways and culminates into the formation of a membrane attack complex that ultimately causes target cell lysis (usually pathogens) The complement system is involved in several important functions in the central nervous system (CNS) that include neurogenesis, synaptic pruning, apoptosis, and neuronal plasticity. Here, we discuss how the complement system is involved in the effective functioning of CNS, while also contributing to chronic neuroinflammation leading to neurodegenerative disorders such as Alzheimer’s disease. We also discuss potential targets in the complement system for stopping its harmful effects via neuroinflammation and provide perspective for the direction of future research in this field.
Collapse
|
9
|
Ruiz-Pérez G, Ruiz de Martín Esteban S, Marqués S, Aparicio N, Grande MT, Benito-Cuesta I, Martínez-Relimpio AM, Arnanz MA, Tolón RM, Posada-Ayala M, Cravatt BF, Esteban JA, Romero J, Palenzuela R. Potentiation of amyloid beta phagocytosis and amelioration of synaptic dysfunction upon FAAH deletion in a mouse model of Alzheimer's disease. J Neuroinflammation 2021; 18:223. [PMID: 34587978 PMCID: PMC8482614 DOI: 10.1186/s12974-021-02276-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 09/15/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The complex pathophysiology of Alzheimer's disease (AD) hampers the development of effective treatments. Attempts to prevent neurodegeneration in AD have failed so far, highlighting the need for further clarification of the underlying cellular and molecular mechanisms. Neuroinflammation seems to play a crucial role in disease progression, although its specific contribution to AD pathogenesis remains elusive. We have previously shown that the modulation of the endocannabinoid system (ECS) renders beneficial effects in a context of amyloidosis, which triggers neuroinflammation. In the 5xFAD model, the genetic inactivation of the enzyme that degrades anandamide (AEA), the fatty acid amide hydrolase (FAAH), was associated with a significant amelioration of the memory deficit. METHODS In this work, we use electrophysiology, flow cytometry and molecular analysis to evaluate the cellular and molecular mechanisms underlying the improvement associated to the increased endocannabinoid tone in the 5xFAD mouse- model. RESULTS We demonstrate that the chronic enhancement of the endocannabinoid tone rescues hippocampal synaptic plasticity in the 5xFAD mouse model. At the CA3-CA1 synapse, both basal synaptic transmission and long-term potentiation (LTP) of synaptic transmission are normalized upon FAAH genetic inactivation, in a CB1 receptor (CB1R)- and TRPV1 receptor-independent manner. Dendritic spine density in CA1 pyramidal neurons, which is notably decreased in 6-month-old 5xFAD animals, is also restored. Importantly, we reveal that the expression of microglial factors linked to phagocytic activity, such as TREM2 and CTSD, and other factors related to amyloid beta clearance and involved in neuron-glia crosstalk, such as complement component C3 and complement receptor C3AR, are specifically upregulated in 5xFAD/FAAH-/- animals. CONCLUSION In summary, our findings support the therapeutic potential of modulating, rather than suppressing, neuroinflammation in Alzheimer's disease. In our model, the long-term enhancement of the endocannabinoid tone triggered augmented microglial activation and amyloid beta phagocytosis, and a consequent reversal in the neuronal phenotype associated to the disease.
Collapse
Affiliation(s)
- Gonzalo Ruiz-Pérez
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | | | - Sharai Marqués
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Noelia Aparicio
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - M Teresa Grande
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Irene Benito-Cuesta
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Ana M Martínez-Relimpio
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - M Andrea Arnanz
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Rosa M Tolón
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - María Posada-Ayala
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Benjamin F Cravatt
- The Skaggs Institute for Chemical Biology and Departments of Cell Biology and Chemistry, The Scripps Research Institute, La Jolla, San Diego, CA, 92037, USA
| | - José A Esteban
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Julián Romero
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain.
| | - Rocío Palenzuela
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain.
| |
Collapse
|
10
|
Tao L, Liu Q, Zhang F, Fu Y, Zhu X, Weng X, Han H, Huang Y, Suo Y, Chen L, Gao X, Wei X. Microglia modulation with 1070-nm light attenuates Aβ burden and cognitive impairment in Alzheimer's disease mouse model. LIGHT, SCIENCE & APPLICATIONS 2021; 10:179. [PMID: 34493703 PMCID: PMC8423759 DOI: 10.1038/s41377-021-00617-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/29/2021] [Accepted: 08/17/2021] [Indexed: 05/05/2023]
Abstract
Photobiomodulation, by utilizing low-power light in the visible and near-infrared spectra to trigger biological responses in cells and tissues, has been considered as a possible therapeutic strategy for Alzheimer's disease (AD), while its specific mechanisms have remained elusive. Here, we demonstrate that cognitive and memory impairment in an AD mouse model can be ameliorated by 1070-nm light via reducing cerebral β-amyloid (Aβ) burden, the hallmark of AD. The glial cells, including microglia and astrocytes, play important roles in Aβ clearance. Our results show that 1070-nm light pulsed at 10 Hz triggers microglia rather than astrocyte responses in AD mice. The 1070-nm light-induced microglia responses with alteration in morphology and increased colocalization with Aβ are sufficient to reduce Aβ load in AD mice. Moreover, 1070-nm light pulsed at 10 Hz can reduce perivascular microglia and promote angiogenesis to further enhance Aβ clearance. Our study confirms the important roles of microglia and cerebral vessels in the use of 1070-nm light for the treatment of AD mice and provides a framework for developing a novel therapeutic approach for AD.
Collapse
Affiliation(s)
- Lechan Tao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Qi Liu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Fuli Zhang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Yuting Fu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Xi Zhu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Xiaofu Weng
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Hongbin Han
- Institute of Medical Technology, Peking University Health Science Center, Beijing, 100191, China
- Department of Radiology, Peking University Third Hospital, Beijing, 100191, China
- Key Lab of Magnetic Resonance Imaging Device and Technique, Beijing, 100191, China
| | - Yong Huang
- Zhejiang Brainhealth Medical Technology Co., Ltd, Hangzhou, 314400, China
| | - Yuanzhen Suo
- Biomedical Pioneering Innovation Center, Peking University, Beijing, 100871, China
- School of Life Sciences, Peking University, Beijing, 100871, China
| | - Liang Chen
- Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, 200040, China.
- Tianqiao and Chrissy Chen Institute for Clinical Translational Research, Huashan Hospital, Shanghai, 200040, China.
| | - Xiaoling Gao
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Xunbin Wei
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China.
- Institute of Medical Technology, Peking University Health Science Center, Beijing, 100191, China.
- Biomedical Engineering Department, Peking University, Beijing, 100081, China.
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital & Institute, Beijing, 100142, China.
| |
Collapse
|
11
|
Wu Y, Shao W, Todd TW, Tong J, Yue M, Koga S, Castanedes-Casey M, Librero AL, Lee CW, Mackenzie IR, Dickson DW, Zhang YJ, Petrucelli L, Prudencio M. Microglial lysosome dysfunction contributes to white matter pathology and TDP-43 proteinopathy in GRN-associated FTD. Cell Rep 2021; 36:109581. [PMID: 34433069 PMCID: PMC8491969 DOI: 10.1016/j.celrep.2021.109581] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 06/07/2021] [Accepted: 07/29/2021] [Indexed: 11/04/2022] Open
Abstract
Loss-of-function mutations in the progranulin gene (GRN), which encodes progranulin (PGRN), are a major cause of frontotemporal dementia (FTD). GRN-associated FTD is characterized by TDP-43 inclusions and neuroinflammation, but how PGRN loss causes disease remains elusive. We show that Grn knockout (KO) mice have increased microgliosis in white matter and an accumulation of myelin debris in microglial lysosomes in the same regions. Accumulation of myelin debris is also observed in white matter of patients with GRN-associated FTD. In addition, our findings also suggest that PGRN insufficiency in microglia leads to impaired lysosomal-mediated clearance of myelin debris. Finally, Grn KO mice that are deficient in cathepsin D (Ctsd), a key lysosomal enzyme, have augmented myelin debris and increased neuronal TDP-43 pathology. Together, our data strongly imply that PGRN loss affects microglial activation and lysosomal function, resulting in the accumulation of myelin debris and contributing to TDP-43 pathology. Wu et al. show increased microgliosis in white matter of Grn knockout mice. Microglial lysosomes accumulate myelin debris in both Grn knockout mice and patients with GRN-associated FTD, and reducing cathespin D levels exacerbates both myelin debris accumulation and pTdp-43 aggregation. Thus, lysosomal dysfunction affects these pathologies in GRN-related FTD.
Collapse
Affiliation(s)
- Yanwei Wu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Wei Shao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Tiffany W Todd
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Jimei Tong
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Mei Yue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Shunsuke Koga
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Ariston L Librero
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Chris W Lee
- Atlantic Health System, Morristown, NJ 07960, USA; Biomedical Research Institute of New Jersey, Cedar Knolls, NJ 07927, USA
| | - Ian R Mackenzie
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - Yong-Jie Zhang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA.
| | - Mercedes Prudencio
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA.
| |
Collapse
|
12
|
van der Spek SJF, Gonzalez-Lozano MA, Koopmans F, Miedema SSM, Paliukhovich I, Smit AB, Li KW. Age-Dependent Hippocampal Proteomics in the APP/PS1 Alzheimer Mouse Model: A Comparative Analysis with Classical SWATH/DIA and directDIA Approaches. Cells 2021; 10:cells10071588. [PMID: 34202490 PMCID: PMC8304546 DOI: 10.3390/cells10071588] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 01/05/2023] Open
Abstract
Alzheimer’s disease (AD) is the most common neurodegenerative disorder in the human population, for which there is currently no cure. The cause of AD is unknown; however, the toxic effects of amyloid-β (Aβ) are believed to play a role in its onset. To investigate this, we examined changes in global protein levels in a hippocampal synaptosome fraction of the Amyloid Precursor Protein swe/Presenelin 1 dE9 (APP/PS1) mouse model of AD at 6 and 12 months of age (moa). Data independent acquisition (DIA), or Sequential Window Acquisition of all THeoretical fragment-ion (SWATH), was used for a quantitative label-free proteomics analysis. We first assessed the usefulness of a recently improved directDIA workflow as an alternative to conventional DIA data analysis using a project-specific spectral library. Subsequently, we applied directDIA to the 6- and 12-moa APP/PS1 datasets and applied the Mass Spectrometry Downstream Analysis Pipeline (MS-DAP) for differential expression analysis and candidate discovery. We observed most regulation at 12-moa, in particular of proteins involved in Aβ homeostasis and microglial-dependent processes, like synaptic pruning and the immune response, such as APOE, CLU and C1QA-C. All proteomics data are available via ProteomeXchange with identifier PXD025777.
Collapse
|
13
|
Mendes MS, Majewska AK. An overview of microglia ontogeny and maturation in the homeostatic and pathological brain. Eur J Neurosci 2021; 53:3525-3547. [PMID: 33835613 PMCID: PMC8225243 DOI: 10.1111/ejn.15225] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/17/2021] [Accepted: 04/01/2021] [Indexed: 12/21/2022]
Abstract
Microglia are the resident immune cells of the central nervous system (CNS) and are increasingly recognized as critical players in development, brain homeostasis, and disease pathogenesis. The lifespan, maintenance, proliferation, and turnover of microglia are important factors that regulate microglial behavior and affect their roles in the CNS. However, emerging evidence suggests that microglia are morphologically and phenotypically distinct in different brain areas, at different ages, and during disease. Ongoing research focuses on understanding how microglia acquire specific phenotypes in response to extrinsic cues in the environment and how phenotypes are specified by intrinsic properties of different populations of microglia. With the development of pharmacological and genetic tools that allow the investigation of microglia in vivo, there have been considerable advances in understanding molecular signatures of both homeostatic microglia and those reacting to injury and disease. Here, we review the master gene regulators that define microglia as well as discuss the evidence that microglia are heterogeneous and fall into distinct clusters that display specific intrinsic properties and perform unique tasks in different settings. Taken together, the information presented supports the idea that microglia morphology and transcriptional heterogeneity should be considered when studying the complex nature of microglia and their roles in brain health and disease.
Collapse
Affiliation(s)
- Monique S Mendes
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
| | - Ania K Majewska
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
- Center for Visual Science, University of Rochester, Rochester, NY, USA
| |
Collapse
|
14
|
The Neuromelanin Paradox and Its Dual Role in Oxidative Stress and Neurodegeneration. Antioxidants (Basel) 2021; 10:antiox10010124. [PMID: 33467040 PMCID: PMC7829956 DOI: 10.3390/antiox10010124] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 12/12/2022] Open
Abstract
Aging is associated with an increasing dysfunction of key brain homeostasis mechanisms and represents the main risk factor across most neurodegenerative disorders. However, the degree of dysregulation and the affectation of specific pathways set apart normal aging from neurodegenerative disorders. In particular, the neuronal metabolism of catecholaminergic neurotransmitters appears to be a specifically sensitive pathway that is affected in different neurodegenerations. In humans, catecholaminergic neurons are characterized by an age-related accumulation of neuromelanin (NM), rendering the soma of the neurons black. This intracellular NM appears to serve as a very efficient quencher for toxic molecules. However, when a neuron degenerates, NM is released together with its load (many undegraded cellular components, transition metals, lipids, xenobiotics) contributing to initiate and worsen an eventual immune response, exacerbating the oxidative stress, ultimately leading to the neurodegenerative process. This review focuses on the analysis of the role of NM in normal aging and neurodegeneration related to its capabilities as an antioxidant and scavenging of harmful molecules, versus its involvement in oxidative stress and aberrant immune response, depending on NM saturation state and its extracellular release.
Collapse
|
15
|
Microglia Do Not Take Up Soluble Amyloid-beta Peptides, But Partially Degrade Them by Secreting Insulin-degrading Enzyme. Neuroscience 2020; 443:30-43. [PMID: 32697980 DOI: 10.1016/j.neuroscience.2020.07.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/03/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022]
Abstract
Microglia play important roles in the pathogenesis of Alzheimer's disease (AD), in part, by affecting the clearance of amyloid-β (Aβ) peptides. Most studies, however, used synthetic soluble Aβ (sAβ) at higher concentrations. The exact mechanisms underlying microglia-mediated clearance of physiological sAβ at very low concentrations remain unclear. Here we reported that there were much more Iba-1- and CD68-positive microglia and significantly less sAβ left in the brain of adult mice 5 days after the surgery of sAβ microinjection compared to 2 h after the surgery (p < 0.05). However, very few Iba-1- and CD68-positive microglia co-localized with microinjected fluorescently labeled sAβ (FLsAβ42) 5 days after the surgery. Also, there was no co-localization of FLsAβ42 with a lysosomal marker (LAMP-1) 5 days after the surgery. There was no significant difference in the percentage of Aβ+/PE-CD11b+/APC-CD45low microglia between the control group and the group microinjected with TBS-soluble Aβ extracted from the brains of AD patients (p > 0.05). The degradation of physiological sAβ was prevented by a highly selective insulin-degrading enzyme inhibitor (Ii1) but not by a phagocytosis inhibitor (polyinosinic acid) or pinocytosis inhibitor (cytochalasin B) in vitro. Furthermore, the reduction of synthetic and physiological sAβ in the brain was partially prevented by the co-injection of Ii1 in vivo (p < 0.05). Our results demonstrate that microglia do not take up synthetic or physiological sAβ, but partially degrade it via the secretion of insulin-degrading enzyme, which will be beneficial for understanding how sAβ is removed from the brain by microglia.
Collapse
|
16
|
Neuroinflammation and Neurogenesis in Alzheimer's Disease and Potential Therapeutic Approaches. Int J Mol Sci 2020; 21:ijms21030701. [PMID: 31973106 PMCID: PMC7037892 DOI: 10.3390/ijms21030701] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/17/2020] [Accepted: 01/19/2020] [Indexed: 12/17/2022] Open
Abstract
In adult brain, new neurons are generated throughout adulthood in the subventricular zone and the dentate gyrus; this process is commonly known as adult neurogenesis. The regulation or modulation of adult neurogenesis includes various intrinsic pathways (signal transduction pathway and epigenetic or genetic modulation pathways) or extrinsic pathways (metabolic growth factor modulation, vascular, and immune system pathways). Altered neurogenesis has been identified in Alzheimer's disease (AD), in both human AD brains and AD rodent models. The exact mechanism of the dysregulation of adult neurogenesis in AD has not been completely elucidated. However, neuroinflammation has been demonstrated to alter adult neurogenesis. The presence of various inflammatory components, such as immune cells, cytokines, or chemokines, plays a role in regulating the survival, proliferation, and maturation of neural stem cells. Neuroinflammation has also been considered as a hallmark neuropathological feature of AD. In this review, we summarize current, state-of-the art perspectives on adult neurogenesis, neuroinflammation, and the relationship between these two phenomena in AD. Furthermore, we discuss the potential therapeutic approaches, focusing on the anti-inflammatory and proneurogenic interventions that have been reported in this field.
Collapse
|
17
|
Cellular and Molecular Mediators of Neuroinflammation in Alzheimer Disease. Int Neurourol J 2019; 23:S54-62. [PMID: 31795604 PMCID: PMC6905206 DOI: 10.5213/inj.1938184.092] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 11/14/2019] [Indexed: 12/26/2022] Open
Abstract
Alzheimer disease (AD) is a neurodegenerative disorder characterized by the loss of neuronal cells and the progressive decline of cognitive function. The major pathological culprit of AD is aggregation of amyloid-β (Aβ) and hyperphosphorylation of tau, eventually leading to progressive neuronal cell death and brain atrophy. However, the detailed molecular and cellular mechanisms underlying AD development as a result of neuronal cell death are little known. Although several hypotheses have been proposed regarding the development of AD, increasingly many studies suggest that the pathological progress of AD is not restricted to neuronal components such as Aβ and tau, but is also closely related to inflammatory responses in the brain. Abnormalities of Aβ and tau cause activity of pattern recognition receptors on the brain’s immune cells, including microglia and astrocytes, and trigger the innate immune system by releasing inflammatory mediators in the pathogenesis of AD. In this review, we present a basic overview of the current knowledge regarding inflammation and molecular mediators in the pathological progress of AD.
Collapse
|
18
|
Galloway DA, Phillips AEM, Owen DRJ, Moore CS. Phagocytosis in the Brain: Homeostasis and Disease. Front Immunol 2019; 10:790. [PMID: 31040847 PMCID: PMC6477030 DOI: 10.3389/fimmu.2019.00790] [Citation(s) in RCA: 172] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/26/2019] [Indexed: 12/28/2022] Open
Abstract
Microglia are resident macrophages of the central nervous system and significantly contribute to overall brain function by participating in phagocytosis during development, homeostasis, and diseased states. Phagocytosis is a highly complex process that is specialized for the uptake and removal of opsonized and non-opsonized targets, such as pathogens, apoptotic cells, and cellular debris. While the role of phagocytosis in mediating classical innate and adaptive immune responses has been known for decades, it is now appreciated that phagocytosis is also critical throughout early neural development, homeostasis, and initiating repair mechanisms. As such, modulating phagocytic processes has provided unexplored avenues with the intent of developing novel therapeutics that promote repair and regeneration in the CNS. Here, we review the functional consequences that phagocytosis plays in both the healthy and diseased CNS, and summarize how phagocytosis contributes to overall pathophysiological mechanisms involved in brain injury and repair.
Collapse
Affiliation(s)
- Dylan A Galloway
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Alexandra E M Phillips
- Division of Brain Sciences, Department of Medicine Hammersmith Hospital, Imperial College London, London, United Kingdom
| | - David R J Owen
- Division of Brain Sciences, Department of Medicine Hammersmith Hospital, Imperial College London, London, United Kingdom
| | - Craig S Moore
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| |
Collapse
|
19
|
Perea JR, Llorens-Martín M, Ávila J, Bolós M. The Role of Microglia in the Spread of Tau: Relevance for Tauopathies. Front Cell Neurosci 2018; 12:172. [PMID: 30042659 PMCID: PMC6048186 DOI: 10.3389/fncel.2018.00172] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 06/01/2018] [Indexed: 01/01/2023] Open
Abstract
Tauopathies are neurodegenerative diseases which course with the accumulation of Tau, mainly in neurons. In addition, Tau accumulates in a hyperphosphorylated and aggregated form. This protein is released into the extracellular space and spreads following a stereotypical pattern, inducing the development of the disease through connected regions of the brain. Microglia-the macrophages of the brain-are involved in maintaining brain homeostasis. They perform a variety of functions related to the surveillance and clearance of pathological proteins, among other dead cells and debris, from the extracellular space that could compromise brain equilibrium. This review focuses on the role played by microglia in tauopathies, specifically in Alzheimer's disease (AD), and how the uncoupling of activation/phagocytosis functions can have fatal consequences leading to the development of the pathology.
Collapse
Affiliation(s)
- Juan R Perea
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa", CBMSO, CSIC, Madrid, Spain.,Network Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - María Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa", CBMSO, CSIC, Madrid, Spain.,Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - Jesús Ávila
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa", CBMSO, CSIC, Madrid, Spain.,Network Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Marta Bolós
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa", CBMSO, CSIC, Madrid, Spain.,Network Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| |
Collapse
|
20
|
Bedoui Y, Neal JW, Gasque P. The Neuro-Immune-Regulators (NIREGs) Promote Tissue Resilience; a Vital Component of the Host's Defense Strategy against Neuroinflammation. J Neuroimmune Pharmacol 2018; 13:309-329. [PMID: 29909495 DOI: 10.1007/s11481-018-9793-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/24/2018] [Indexed: 01/29/2023]
Abstract
An effective protective inflammatory response in the brain is crucial for the clearance of pathogens (e.g. microbes, amyloid fibrils, prionSC) and should be closely regulated. However, the CNS seems to have limited tissue resilience to withstand the detrimental effects of uncontrolled inflammation compromising functional recovery and tissue repair. Newly described neuro-immune-regulators (NIREGs) are functionally related proteins regulating the severity and duration of the host inflammatory response. NIREGs such as CD200, CD47 and CX3CL1 are vital for increasing tissue resilience and are constitutively expressed by neurons. The interaction with co-receptors (CD200R, CD172a, CX3CR1) will maintain microglia in the resting phenotype, directing aggressive microglia phenotype and limiting bystander injuries. Neurons can also express many of the complement NIREGs (CD55, CD46, CD59 and factor H). Neurons and glia also express suppressor of cytokine signaling proteins (SOCS) down regulating janus kinase-signal transducer and activator of transcription (JAK/STAT) pathway and to lead to the polarization of microglia towards anti-inflammatory phenotype. Other NIREGs such as serine protease inhibitors (serpins) and thrombomodulin (CD141) inhibit neurotoxic systemic coagulation proteins such as thrombin. The unfolded protein response (UPR) detects misfolded proteins and other stressors to prevent irreversible cell injury. Microglial pattern recognition receptors (PRR) (TREM-2, CR3, FcγR) are important to clear apoptotic cells and cellular debris but in non-phlogystic manner through inhibitory signaling pathways. The TYRO3, Axl, Mer (TAM) tyrosine receptor kinases activated by Gas 6 and PROS1 regulate inflammation by inhibiting Toll like receptors (TLR) /JAK-STAT activation and contribute to NIREG's functions.
Collapse
Affiliation(s)
- Yosra Bedoui
- Université de la Réunion, CRNS 9192, INSERM U1187, IRD249, Unité Mixte Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Plateforme Technologique CYROI, Saint -Clotilde, La Réunion, France
| | - Jim W Neal
- Infection and Immunity, Cardiff University, Henry Wellcome Building, Cardiff, CF14 4XN, UK.
| | - Philippe Gasque
- Laboratoire de biologie, secteur laboratoire d'immunologie Clinique et expérimentale ZOI, LICE-OI, CHU Felix Guyon Bellepierre, St Denis, La Réunion, France.
| |
Collapse
|
21
|
Habib A, Sawmiller D, Hou H, Kanithi M, Tian J, Zeng J, Zi D, He ZX, Sanberg PR, Tan J. Human Cord Blood Serum-Derived APP α-Secretase Cleavage Activity is Mediated by C1 Complement. Cell Transplant 2018; 27:666-676. [PMID: 29871524 PMCID: PMC7020233 DOI: 10.1177/0963689718775941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Alzheimer's Disease (AD) is the leading cause of dementia in the elderly. In healthy individuals, amyloid precursor protein (APP) is cleaved by α-secretase, generating soluble α-amyloid precursor protein (sAPPα), which contributes neuroprotective functions in the neuronal environment. In contrast, in the neurodegenerative environment of AD patients, amyloid-β-peptide (Aβ) of either 40 or 42 residues are generated by increased activity of β- and γ-secretase. These proteins amalgamate in specific regions of the brain, which disrupts neuronal functions and leads to cognitive impairment. Human umbilical cord blood cells (HUCBC) have proven useful as potential immunomodulatory therapies in various models of neurodegenerative diseases, including AD. Our most recent work studied the impact of umbilical cord blood serum (CBS) on modulation of sAPPα production. Heat-sensitive CBS significantly promoted sAPPα production, indicating that heat-sensitive factor(s) play(s) a role in this process. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis was used to determine the molecular source of α-secretase in purified CBS and aged blood serum (AgBS) fraction. Of the proteins identified, the subunits of C1 complex (C1q, C1r, and C1s) and alpha-2-macroglobulin showed significantly greater levels in purified α-CBS fraction (α-CBSF) compared with the AgBS fraction (AgBSF). Specifically, C1 markedly increased sAPPα and alpha-carboxyl-terminal fragment (α-CTF) production in a dose-dependent fashion, whereas C1q alone only minimally increased and C3 did not increase sAPPα production in the absence of sera. Furthermore, C1q markedly increased sAPPα and α-CTF, while decreasing Aβ, in CHO/APPwt cells cultured in the presence of whole sera. These results confirm our initial assumption that APP α-secretase activity in human blood serum is mediated by complement C1, opening a potential therapeutic modality for the future of AD.
Collapse
Affiliation(s)
- Ahsan Habib
- 1 Department of Psychiatry and Behavioral Neurosciences, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Darrell Sawmiller
- 1 Department of Psychiatry and Behavioral Neurosciences, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Huayan Hou
- 1 Department of Psychiatry and Behavioral Neurosciences, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Manasa Kanithi
- 1 Department of Psychiatry and Behavioral Neurosciences, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Jun Tian
- 1 Department of Psychiatry and Behavioral Neurosciences, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Jin Zeng
- 1 Department of Psychiatry and Behavioral Neurosciences, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Dan Zi
- 2 Guizhou Provincial Key Laboratory for Regenerative Medicine, Stem Cell and Tissue Engineering Research Center & Sino-US Joint Laboratory for Medical Sciences, Laboratory Animal Center, Guizhou Medical University Guiyang, China
| | - Zhi-Xu He
- 2 Guizhou Provincial Key Laboratory for Regenerative Medicine, Stem Cell and Tissue Engineering Research Center & Sino-US Joint Laboratory for Medical Sciences, Laboratory Animal Center, Guizhou Medical University Guiyang, China
| | - Paul R Sanberg
- 3 Center for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Jun Tan
- 1 Department of Psychiatry and Behavioral Neurosciences, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| |
Collapse
|
22
|
Jin P, Pan Y, Pan Z, Xu J, Lin M, Sun Z, Chen M, Xu M. Alzheimer-like brain metabolic and structural features in cholesterol-fed rabbit detected by magnetic resonance imaging. Lipids Health Dis 2018; 17:61. [PMID: 29587752 PMCID: PMC5870103 DOI: 10.1186/s12944-018-0705-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Accepted: 03/09/2018] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Hypercholesterolemia is known to increase the risk of AD in later life, the purpose of this study is to illustrate brain metabolic and structural changes in a cholesterol-fed rabbit model of Alzheimer's Disease (AD) by using clinical 3 T Magnetic Resonance Imaging (MRI). METHODS The Institutional Animal Care and Use Committee of Zhejiang Chinese Medical University approved the study. Totally 16 Japanese White Rabbits (JWR) were randomly divided into 2 groups including normal control group fed with routine diet (group NC) and high cholesterol diet group (group CD) fed a 2% cholesterol diet with 0.24 ppm copper in the drinking water for 12 weeks. Magnetic resonance spectroscopy (MRS) and structural image of rabbit brain were performed by using a 3 Tesla (T) MRI scanner with an 8 channel Rabbit coil. The chemical metabolites were identified by LC Model including N-acetylaspartate (NAA), creatine (Cr), glutamate (Glu), glutamine (Gln), Glycerophosphatidylcholine (GPC), phosphorylcholine (PCH), and myoinositol (MI). The relative concentrations (/Cr) were analyzed. Additionally, Amyloid-β (Aβ) accumulation in the brain was measured postmortem. For comparisons of MR and Aβ data between groups, two-tailed t-tests were performed. RESULTS The ratio of NAA/Cr (0.76 ± 0.10) and Glu/Cr (0.90 ± 0.14) in group CD were lower than those in the group NC (0.87 ± 0.06, 1.13 ± 0.22, respectively, P < 0.05). Compared to the group NC (2.88 ± 0.09 cm3, 0.63 ± 0.08 cm3, respectively), the cortical and hippocampal volumes (2.60 ± 0.14 cm3 and 0.47 ± 0.07 cm3, respectively) of rabbits brain decreased in the group CD while the third and lateral ventricular volumes enlarged (44.56 ± 6.01 mm3 vs 31.40 ± 6.14 mm3, 261.40 ± 30.98 mm3 vs 153.81 ± 30.08 mm3, P < 0.05). These metabolic and structural changes were additionally accompanied by the significant increase of Aβ1-42 in the cortex and hippocampus (163.60 ± 16.26 pg/mg and 215.20 ± 69.86 pg/mg, respectively, P < 0.05). CONCLUSION High cholesterol diet can induce the brain metabolic and structural changes of the rabbit including lowered level of NAA and Glu and the atrophy of the brain which were similar to those of human AD.
Collapse
Affiliation(s)
- Ping Jin
- The First Affiliated Hospital of Zhejiang Chinese Medical University, No. 54 Youdian Road, Shangcheng District, Hangzhou, Zhejiang 310006 People’s Republic of China
- The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang China
| | - Yongming Pan
- Laboratory Animal Research Center/Comparative Medical Research Institute, Zhejiang Chinese Medical University, No 548 Binwen Road, Binjiang District, Hangzhou, 310053 China
| | - Zhiyong Pan
- The First Affiliated Hospital of Zhejiang Chinese Medical University, No. 54 Youdian Road, Shangcheng District, Hangzhou, Zhejiang 310006 People’s Republic of China
| | - Jianqin Xu
- Laboratory Animal Research Center/Comparative Medical Research Institute, Zhejiang Chinese Medical University, No 548 Binwen Road, Binjiang District, Hangzhou, 310053 China
| | - Min Lin
- The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang China
| | - Zhichao Sun
- The First Affiliated Hospital of Zhejiang Chinese Medical University, No. 54 Youdian Road, Shangcheng District, Hangzhou, Zhejiang 310006 People’s Republic of China
| | - Minli Chen
- Laboratory Animal Research Center/Comparative Medical Research Institute, Zhejiang Chinese Medical University, No 548 Binwen Road, Binjiang District, Hangzhou, 310053 China
| | - Maosheng Xu
- The First Affiliated Hospital of Zhejiang Chinese Medical University, No. 54 Youdian Road, Shangcheng District, Hangzhou, Zhejiang 310006 People’s Republic of China
| |
Collapse
|
23
|
Daria A, Colombo A, Llovera G, Hampel H, Willem M, Liesz A, Haass C, Tahirovic S. Young microglia restore amyloid plaque clearance of aged microglia. EMBO J 2016; 36:583-603. [PMID: 28007893 DOI: 10.15252/embj.201694591] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 11/24/2016] [Accepted: 11/28/2016] [Indexed: 11/09/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by deposition of amyloid plaques, neurofibrillary tangles, and neuroinflammation. In order to study microglial contribution to amyloid plaque phagocytosis, we developed a novel ex vivo model by co-culturing organotypic brain slices from up to 20-month-old, amyloid-bearing AD mouse model (APPPS1) and young, neonatal wild-type (WT) mice. Surprisingly, co-culturing resulted in proliferation, recruitment, and clustering of old microglial cells around amyloid plaques and clearance of the plaque halo. Depletion of either old or young microglial cells prevented amyloid plaque clearance, indicating a synergistic effect of both populations. Exposing old microglial cells to conditioned media of young microglia or addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) was sufficient to induce microglial proliferation and reduce amyloid plaque size. Our data suggest that microglial dysfunction in AD may be reversible and their phagocytic ability can be modulated to limit amyloid accumulation. This novel ex vivo model provides a valuable system for identification, screening, and testing of compounds aimed to therapeutically reinforce microglial phagocytosis.
Collapse
Affiliation(s)
- Anna Daria
- Biomedical Center (BMC), Ludwig-Maximilians Universität München, Munich, Germany
| | - Alessio Colombo
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Gemma Llovera
- Institute for Stroke and dementia research (ISD), Ludwig-Maximilians Universität München, Munich, Germany
| | - Heike Hampel
- Biomedical Center (BMC), Ludwig-Maximilians Universität München, Munich, Germany
| | - Michael Willem
- Biomedical Center (BMC), Ludwig-Maximilians Universität München, Munich, Germany
| | - Arthur Liesz
- Institute for Stroke and dementia research (ISD), Ludwig-Maximilians Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Christian Haass
- Biomedical Center (BMC), Ludwig-Maximilians Universität München, Munich, Germany .,German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Sabina Tahirovic
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| |
Collapse
|
24
|
Spangenberg EE, Lee RJ, Najafi AR, Rice RA, Elmore MRP, Blurton-Jones M, West BL, Green KN. Eliminating microglia in Alzheimer's mice prevents neuronal loss without modulating amyloid-β pathology. Brain 2016; 139:1265-81. [PMID: 26921617 DOI: 10.1093/brain/aww016] [Citation(s) in RCA: 454] [Impact Index Per Article: 56.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 12/27/2015] [Indexed: 01/07/2023] Open
Abstract
In addition to amyloid-β plaque and tau neurofibrillary tangle deposition, neuroinflammation is considered a key feature of Alzheimer's disease pathology. Inflammation in Alzheimer's disease is characterized by the presence of reactive astrocytes and activated microglia surrounding amyloid plaques, implicating their role in disease pathogenesis. Microglia in the healthy adult mouse depend on colony-stimulating factor 1 receptor (CSF1R) signalling for survival, and pharmacological inhibition of this receptor results in rapid elimination of nearly all of the microglia in the central nervous system. In this study, we set out to determine if chronically activated microglia in the Alzheimer's disease brain are also dependent on CSF1R signalling, and if so, how these cells contribute to disease pathogenesis. Ten-month-old 5xfAD mice were treated with a selective CSF1R inhibitor for 1 month, resulting in the elimination of ∼80% of microglia. Chronic microglial elimination does not alter amyloid-β levels or plaque load; however, it does rescue dendritic spine loss and prevent neuronal loss in 5xfAD mice, as well as reduce overall neuroinflammation. Importantly, behavioural testing revealed improvements in contextual memory. Collectively, these results demonstrate that microglia contribute to neuronal loss, as well as memory impairments in 5xfAD mice, but do not mediate or protect from amyloid pathology.
Collapse
Affiliation(s)
- Elizabeth E Spangenberg
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697-4545, USA
| | - Rafael J Lee
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697-4545, USA
| | - Allison R Najafi
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697-4545, USA
| | - Rachel A Rice
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697-4545, USA
| | - Monica R P Elmore
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697-4545, USA
| | - Mathew Blurton-Jones
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697-4545, USA
| | - Brian L West
- Plexxikon Inc., Berkeley, California, 94710, USA
| | - Kim N Green
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697-4545, USA
| |
Collapse
|
25
|
von Bernhardi R, Heredia F, Salgado N, Muñoz P. Microglia Function in the Normal Brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 949:67-92. [PMID: 27714685 DOI: 10.1007/978-3-319-40764-7_4] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The activation of microglia has been recognized for over a century by their morphological changes. Long slender microglia acquire a short sturdy ramified shape when activated. During the past 20 years, microglia have been accepted as an essential cellular component for understanding the pathogenic mechanism of many brain diseases, including neurodegenerative diseases. More recently, functional studies and imaging in mouse models indicate that microglia are active in the healthy central nervous system. It has become evident that microglia release several signal molecules that play key roles in the crosstalk among brain cells, i.e., astrocytes and oligodendrocytes with neurons, as well as with regulatory immune cells. Recent studies also reveal the heterogeneous nature of microglia diverse functions depending on development, previous exposure to stimulation events, brain region of residence, or pathological state. Subjects to approach by future research are still the unresolved questions regarding the conditions and mechanisms that render microglia protective, capable of preventing or reducing damage, or deleterious, capable of inducing or facilitating the progression of neuropathological diseases. This novel knowledge will certainly change our view on microglia as therapeutic target, shifting our goal from their general silencing to the generation of treatments able to change their activation pattern.
Collapse
Affiliation(s)
- Rommy von Bernhardi
- Escuela de Medicina. Departamento de Neurología, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
| | - Florencia Heredia
- Escuela de Medicina. Departamento de Neurología, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Nicole Salgado
- Escuela de Medicina. Departamento de Neurología, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Paola Muñoz
- Escuela de Medicina. Departamento de Neurología, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| |
Collapse
|
26
|
Kouser L, Madhukaran SP, Shastri A, Saraon A, Ferluga J, Al-Mozaini M, Kishore U. Emerging and Novel Functions of Complement Protein C1q. Front Immunol 2015; 6:317. [PMID: 26175731 PMCID: PMC4484229 DOI: 10.3389/fimmu.2015.00317] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/02/2015] [Indexed: 02/02/2023] Open
Abstract
Complement protein C1q, the recognition molecule of the classical pathway, performs a diverse range of complement and non-complement functions. It can bind various ligands derived from self, non-self, and altered self and modulate the functions of immune and non-immune cells including dendritic cells and microglia. C1q involvement in the clearance of apoptotic cells and subsequent B cell tolerance is more established now. Recent evidence appears to suggest that C1q plays an important role in pregnancy where its deficiency and dysregulation can have adverse effects, leading to preeclampsia, missed abortion, miscarriage or spontaneous loss, and various infections. C1q is also produced locally in the central nervous system, and has a protective role against pathogens and possible inflammatory functions while interacting with aggregated proteins leading to neurodegenerative diseases. C1q role in synaptic pruning, and thus CNS development, its anti-cancer effects as an immune surveillance molecule, and possibly in aging are currently areas of extensive research.
Collapse
Affiliation(s)
- Lubna Kouser
- Centre for Infection, Immunity and Disease Mechanisms, College of Health and Life Sciences, Brunel University London , Uxbridge , UK
| | - Shanmuga Priyaa Madhukaran
- Centre for Infection, Immunity and Disease Mechanisms, College of Health and Life Sciences, Brunel University London , Uxbridge , UK ; Centre for Biotechnology and Bioinformatics, Jawaharlal Nehru Institute for Advanced Studies, School of Life Sciences , Secunderabad , India
| | - Abhishek Shastri
- St. Ann's Hospital, Dorset Healthcare University NHS Foundation Trust , Poole , UK
| | - Anuvinder Saraon
- Centre for Infection, Immunity and Disease Mechanisms, College of Health and Life Sciences, Brunel University London , Uxbridge , UK
| | - Janez Ferluga
- Centre for Infection, Immunity and Disease Mechanisms, College of Health and Life Sciences, Brunel University London , Uxbridge , UK
| | - Maha Al-Mozaini
- Department of Infection and Immunity, King Faisal Specialist Hospital and Research Centre , Riyadh , Saudi Arabia
| | - Uday Kishore
- Centre for Infection, Immunity and Disease Mechanisms, College of Health and Life Sciences, Brunel University London , Uxbridge , UK
| |
Collapse
|
27
|
Koronyo Y, Salumbides BC, Sheyn J, Pelissier L, Li S, Ljubimov V, Moyseyev M, Daley D, Fuchs DT, Pham M, Black KL, Rentsendorj A, Koronyo-Hamaoui M. Therapeutic effects of glatiramer acetate and grafted CD115⁺ monocytes in a mouse model of Alzheimer's disease. Brain 2015; 138:2399-422. [PMID: 26049087 DOI: 10.1093/brain/awv150] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 04/07/2015] [Indexed: 12/27/2022] Open
Abstract
Weekly glatiramer acetate immunization of transgenic mice modelling Alzheimer's disease resulted in retained cognition (Morris water maze test), decreased amyloid-β plaque burden, and regulation of local inflammation through a mechanism involving enhanced recruitment of monocytes. Ablation of bone marrow-derived myeloid cells exacerbated plaque pathology, whereas weekly administration of glatiramer acetate enhanced cerebral recruitment of innate immune cells, which dampened the pathology. Here, we assessed the therapeutic potential of grafted CD115(+) monocytes, injected once monthly into the peripheral blood of transgenic APPSWE/PS1ΔE9 Alzheimer's disease mouse models, with and without weekly immunization of glatiramer acetate, as compared to glatiramer acetate alone. All immune-modulation treatment groups were compared with age-matched phosphate-buffered saline-injected control transgenic and untreated non-transgenic mouse groups. Two independent cohorts of mice were assessed for behavioural performance (6-8 mice/group); treatments started in 10-month-old symptomatic mice and spanned a total of 2 months. For all three treatments, our data suggest a substantial decrease in cognitive deficit as assessed by the Barnes maze test (P < 0.0001-0.001). Improved cognitive function was associated with synaptic preservation and reduction in cerebral amyloid-β protein levels and astrogliosis (P < 0.001 and P < 0.0001), with no apparent additive effects for the combined treatment. The peripherally grafted, green fluorescent protein-labelled and endogenous monocytes, homed to cerebral amyloid plaques and directly engulfed amyloid-β; their recruitment was further enhanced by glatiramer acetate. In glatiramer acetate-immunized mice and, moreover, in the combined treatment group, monocyte recruitment to the brain was coupled with greater elevation of the regulatory cytokine IL10 surrounding amyloid-β plaques. All treated transgenic mice had increased cerebral levels of MMP9 protein (P < 0.05), an enzyme capable of degrading amyloid-β, which was highly expressed by the infiltrating monocytes. In vitro studies using primary cultures of bone marrow monocyte-derived macrophages, demonstrated that glatiramer acetate enhanced the ability of macrophages to phagocytose preformed fibrillar amyloid-β1-42 (P < 0.0001). These glatiramer acetate-treated macrophages exhibited increased expression of the scavenger receptors CD36 and SCARA1 (encoded by MSR1), which can facilitate amyloid-β phagocytosis, and the amyloid-β-degrading enzyme MMP9 (P < 0.0001-0.001). Overall, our studies indicate that increased cerebral infiltration of monocytes, either by enrichment of their levels in the circulation or by weekly immunization with glatiramer acetate, resulted in substantial attenuation of disease progression in murine Alzheimer's models by mechanisms that involved enhanced cellular uptake and enzymatic degradation of toxic amyloid-β as well as regulation of brain inflammation.
Collapse
Affiliation(s)
- Yosef Koronyo
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Brenda C Salumbides
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA 2 F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Julia Sheyn
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Lindsey Pelissier
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Songlin Li
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Vladimir Ljubimov
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Michelle Moyseyev
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - David Daley
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Dieu-Trang Fuchs
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Michael Pham
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Keith L Black
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Altan Rentsendorj
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| | - Maya Koronyo-Hamaoui
- 1 Department of Neurosurgery, Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA 3 Department of Biomedical Sciences, Cedars-Sinai Medical Centre, Los Angeles, CA 90048, USA
| |
Collapse
|
28
|
Xi F, Sang F, Zhou C, Ling Y. Protective effects of Lingguizhugan decoction on amyloid-beta peptide (25-35)-induced cell injury: Anti-inflammatory effects. Neural Regen Res 2014; 7:2867-73. [PMID: 25317138 PMCID: PMC4190944 DOI: 10.3969/j.issn.1673-5374.2012.36.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 10/10/2012] [Indexed: 01/22/2023] Open
Abstract
In the present study, a human neuroblastoma cell line (SH-SY5Y) and BV-2 microglia were treated with amyloid-β peptide (25-35), as a model of Alzheimer's disease, to evaluate the protective effects of 10-3-10-8 g/mL Lingguizhugan decoction and to examine the underlying anti-inflammatory mechanism. Lingguizhugan decoction significantly enhanced the viability of SH-SY5Y cells with amyloid-β peptide-induced injury, and lowered levels of interleukin-1β, interleukin-6, tumor necrosis factor-α and nitric oxide in the culture supernatant of activated BV-2 microglia. The effects of 10-3 g/mL Lingguizhugan decoction were more significant. These results suggest that Lingguizhugan decoction can protect SH-SY5Y cells against amyloid-β peptide (25-35)-induced injury in a dose-dependent manner by inhibiting overexpression of inflammatory factors by activated microglia.
Collapse
Affiliation(s)
- Feifei Xi
- Basic Medicine College, Nanjing University of Chinese Medicine, Nanjing 210046, Jiangsu Province, China
| | - Feng Sang
- Henan Clinical Research Center of AIDS Controlled with Traditional Chinese Medicine, the First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou 450003, Henan Province, China
| | - Chunxiang Zhou
- Basic Medicine College, Nanjing University of Chinese Medicine, Nanjing 210046, Jiangsu Province, China ; Nanjing BenQ Hospital, Nanjing 210036, Jiangsu Province, China
| | - Yun Ling
- Basic Medicine College, Nanjing University of Chinese Medicine, Nanjing 210046, Jiangsu Province, China
| |
Collapse
|
29
|
Activation of intrinsic immune responses and microglial phagocytosis in an ex vivo spinal cord slice culture model of West Nile virus infection. J Virol 2014; 88:13005-14. [PMID: 25165111 DOI: 10.1128/jvi.01994-14] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED West Nile virus (WNV) is a neurotropic flavivirus that causes significant neuroinvasive disease involving the brain and/or spinal cord. Experimental mouse models of WNV infection have established the importance of innate and adaptive immune responses in controlling the extent and severity of central nervous system (CNS) disease. However, differentiating between immune responses that are intrinsic to the CNS and those that are dependent on infiltrating inflammatory cells has proven difficult. We used a murine ex vivo spinal cord slice culture (SCSC) model to determine the innate immune processes specific to the CNS during WNV infections. By 7 days after ex vivo infection of SCSCs, the majority of neurons and a substantial percentage of astrocytes were infected with WNV, resulting in apoptotic cell death and astrogliosis. Microglia, the resident immune cells of the CNS, were activated by WNV infection, as exemplified by their amoeboid morphology, the development of filopodia and lamellipodia, and phagocytosis of WNV-infected cells and debris. Microglial cell activation was concomitant with increased expression of proinflammatory cytokines and chemokines, including CXCL10, CXCL1, CCL5, CCL3, CCL2, tumor necrosis factor alpha (TNF-α), TNF-related apoptosis-inducing ligand (TRAIL), and interleukin-6 (IL-6). The application of minocycline, an inhibitor of neuroinflammation, altered the WNV-induced proinflammatory cytokine/chemokine expression profile, with inhibited production of CCL5, CCL2, and IL-6. Our findings establish that CNS-resident cells have the capacity to initiate a robust innate immune response against WNV infection in the absence of infiltrating inflammatory cells and systemic immune responses. IMPORTANCE There are no specific treatments of proven efficacy available for WNV neuroinvasive disease. A better understanding of the pathogenesis of WNV CNS infection is crucial for the rational development of novel therapies. Development of a spinal cord slice culture (SCSC) model facilitates the study of WNV pathogenesis and allows investigation of the intrinsic immune responses of the CNS. Our studies demonstrate that robust CNS innate immune responses, including microglial activation and proinflammatory cytokine/chemokine production, develop independently of contributions from the peripheral immune system and CNS-infiltrating inflammatory cells.
Collapse
|
30
|
Bernstein KE, Koronyo Y, Salumbides BC, Sheyn J, Pelissier L, Lopes DHJ, Shah KH, Bernstein EA, Fuchs DT, Yu JJY, Pham M, Black KL, Shen XZ, Fuchs S, Koronyo-Hamaoui M. Angiotensin-converting enzyme overexpression in myelomonocytes prevents Alzheimer's-like cognitive decline. J Clin Invest 2014; 124:1000-12. [PMID: 24487585 DOI: 10.1172/jci66541] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 11/18/2013] [Indexed: 11/17/2022] Open
Abstract
Cognitive decline in patients with Alzheimer's disease (AD) is associated with elevated brain levels of amyloid β protein (Aβ), particularly neurotoxic Aβ(1-42). Angiotensin-converting enzyme (ACE) can degrade Aβ(1-42), and ACE overexpression in myelomonocytic cells enhances their immune function. To examine the effect of targeted ACE overexpression on AD, we crossed ACE(10/10) mice, which overexpress ACE in myelomonocytes using the c-fms promoter, with the transgenic APP(SWE)/PS1(ΔE9) mouse model of AD (AD⁺). Evaluation of brain tissue from these AD⁺ACE(10/10) mice at 7 and 13 months revealed that levels of both soluble and insoluble brain Aβ(1-42) were reduced compared with those in AD⁺ mice. Furthermore, both plaque burden and astrogliosis were drastically reduced. Administration of the ACE inhibitor ramipril increased Aβ levels in AD⁺ACE(10/10) mice compared with the levels induced by the ACE-independent vasodilator hydralazine. Overall, AD⁺ACE(10/10) mice had less brain-infiltrating cells, consistent with reduced AD-associated pathology, though ACE-overexpressing macrophages were abundant around and engulfing Aβ plaques. At 11 and 12 months of age, the AD⁺ACE(10/WT) and AD⁺ACE(10/10) mice were virtually equivalent to non-AD mice in cognitive ability, as assessed by maze-based behavioral tests. Our data demonstrate that an enhanced immune response, coupled with increased myelomonocytic expression of catalytically active ACE, prevents cognitive decline in a murine model of AD.
Collapse
|
31
|
Le Marrec-Croq F, Bocquet-Garcon A, Vizioli J, Vancamp C, Drago F, Franck J, Wisztorski M, Salzet M, Sautiere PE, Lefebvre C. Calreticulin contributes to C1q-dependent recruitment of microglia in the leech Hirudo medicinalis following a CNS injury. Med Sci Monit 2014; 20:644-53. [PMID: 24747831 PMCID: PMC3999160 DOI: 10.12659/msm.890091] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background The medicinal leech is considered as a complementary and appropriate model to study immune functions in the central nervous system (CNS). In a context in which an injured leech’s CNS can naturally restore normal synaptic connections, the accumulation of microglia (immune cells of the CNS that are exclusively resident in leeches) has been shown to be essential at the lesion to engage the axonal sprouting. HmC1q (Hm for Hirudo medicinalis) possesses chemotactic properties that are important in the microglial cell recruitment by recognizing at least a C1q binding protein (HmC1qBP alias gC1qR). Material/Methods Recombinant forms of C1q were used in affinity purification and in vitro chemotaxis assays. Anti-calreticulin antibodies were used to neutralize C1q-mediated chemotaxis and locate the production of calreticulin in leech CNS. Results A newly characterized leech calreticulin (HmCalR) has been shown to interact with C1q and participate to the HmC1q-dependent microglia accumulation. HmCalR, which has been detected in only some microglial cells, is consequently a second binding protein for HmC1q, allowing the chemoattraction of resident microglia in the nerve repair process. Conclusions These data give new insight into calreticulin/C1q interaction in an immune function of neuroprotection, suggesting another molecular target to use in investigation of microglia reactivity in a model of CNS injury.
Collapse
Affiliation(s)
- Francoise Le Marrec-Croq
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| | - Annelise Bocquet-Garcon
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| | - Jacopo Vizioli
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| | - Christelle Vancamp
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| | - Francesco Drago
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| | - Julien Franck
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| | - Maxence Wisztorski
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| | - Michel Salzet
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| | - Pierre-Eric Sautiere
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| | - Christophe Lefebvre
- Laboratoire de Spectrométrie de Masse Biologique Fondamentale et Appliquée - EA4550, Université Lille Nord de France, University of Lille 1, Villeneuve d'Ascq, France
| |
Collapse
|
32
|
Mulder SD, Nielsen HM, Blankenstein MA, Eikelenboom P, Veerhuis R. Apolipoproteins E and J interfere with amyloid-beta uptake by primary human astrocytes and microglia in vitro. Glia 2014; 62:493-503. [PMID: 24446231 DOI: 10.1002/glia.22619] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 11/30/2013] [Accepted: 12/06/2013] [Indexed: 12/12/2022]
Abstract
Defective clearance of the amyloid-β peptide (Aβ) from the brain is considered a strong promoter in Alzheimer's disease (AD) pathogenesis. Astrocytes and microglia are important mediators of Aβ clearance and Aβ aggregation state and the presence of amyloid associated proteins (AAPs), such as Apolipoproteins E and J (ApoE and ApoJ), may influence Aβ clearance by these cells. Here we set out to investigate whether astrocytes and microglia differ in uptake efficiency of Aβ oligomers (Aβoligo ) and Aβ fibrils (Aβfib ), and whether the Aβ aggregation state and/or presence of AAPs affect Aβ uptake in these cells in vitro. Adult human primary microglia and astrocytes, isolated from short delay post-mortem brain tissue, were exposed to either Aβoligo or Aβfib alone or combined with a panel of certain AAPs whereafter Aβ-positive cells were quantified using flow cytometry. Upon exposure to Aβ combined with ApoE, ApoJ, α1-antichymotrypsin (ACT) and a combination of serum amyloid P and complement C1q (SAP-C1q), a clear reduction in astrocytic but not microglial Aβoligo uptake, was observed. In contrast, Aβfib uptake was strongly reduced in the presence of AAPs in microglia, but not in astrocytes. These data provide the first evidence of distinct roles of microglia and astrocytes in Aβ clearance. More importantly we show that Aβ clearance by glial cells is negatively affected by AAPs like ApoE and ApoJ. Thus, targeting the association of Aβ with AAPs, such as ApoE and ApoJ, could serve as a therapeutic strategy to increase Aβ clearance by glial cells.
Collapse
Affiliation(s)
- Sandra D Mulder
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands; Alzheimer Center, VU University Medical Center, Amsterdam, The Netherlands
| | | | | | | | | |
Collapse
|
33
|
Ghiso J, Fossati S, Rostagno A. Amyloidosis associated with cerebral amyloid angiopathy: cell signaling pathways elicited in cerebral endothelial cells. J Alzheimers Dis 2014; 42 Suppl 3:S167-76. [PMID: 24670400 PMCID: PMC4467213 DOI: 10.3233/jad-140027] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Substantial genetic, biochemical, and in vivo data indicate that progressive accumulation of amyloid-β (Aβ) plays a central role in the pathogenesis of Alzheimer's disease (AD). Historically centered in the importance of parenchymal plaques, the role of cerebral amyloid angiopathy (CAA)--a frequently neglected amyloid deposit present in >80% of AD cases--for the mechanism of disease pathogenesis is now starting to emerge. CAA consistently associates with microvascular modifications, ischemic lesions, micro- and macro-hemorrhages, and dementia, progressively affecting cerebral blood flow, altering blood-brain barrier permeability, interfering with brain clearance mechanisms and triggering a cascade of deleterious pro-inflammatory and metabolic events that compromise the integrity of the neurovascular unit. New evidence highlights the contribution of pre-fibrillar Aβ in the induction of cerebral endothelial cell dysfunction. The recently discovered interaction of oligomeric Aβ species with TRAIL DR4 and DR5 cell surface death receptors mediates the engagement of mitochondrial pathways and sequential activation of multiple caspases, eliciting a cascade of cell death mechanisms while unveiling an opportunity for exploring mechanistic-based therapeutic interventions to preserve the integrity of the neurovascular unit.
Collapse
Affiliation(s)
- Jorge Ghiso
- Department of Pathology, New York University School of Medicine, New York, NY, USA Department of Psychiatry, New York University School of Medicine, New York, NY, USA
| | - Silvia Fossati
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Agueda Rostagno
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| |
Collapse
|
34
|
Meraz-Ríos MA, Toral-Rios D, Franco-Bocanegra D, Villeda-Hernández J, Campos-Peña V. Inflammatory process in Alzheimer's Disease. Front Integr Neurosci 2013; 7:59. [PMID: 23964211 PMCID: PMC3741576 DOI: 10.3389/fnint.2013.00059] [Citation(s) in RCA: 251] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 07/25/2013] [Indexed: 12/26/2022] Open
Abstract
Alzheimer Disease (AD) is a neurodegenerative disorder and the most common form of dementia. Histopathologically is characterized by the presence of two major hallmarks, the intracellular neurofibrillary tangles (NFTs) and extracellular neuritic plaques (NPs) surrounded by activated astrocytes and microglia. NFTs consist of paired helical filaments of truncated tau protein that is abnormally hyperphosphorylated. The main component in the NP is the amyloid-β peptide (Aβ), a small fragment of 40–42 amino acids with a molecular weight of 4 kD. It has been proposed that the amyloid aggregates and microglia activation are able to favor the neurodegenerative process observed in AD patients. However, the role of inflammation in AD is controversial, because in early stages the inflammation could have a beneficial role in the pathology, since it has been thought that the microglia and astrocytes activated could be involved in Aβ clearance. Nevertheless the chronic activation of the microglia has been related with an increase of Aβ and possibly with tau phosphorylation. Studies in AD brains have shown an upregulation of complement molecules, pro-inflammatory cytokines, acute phase reactants and other inflammatory mediators that could contribute with the neurodegenerative process. Clinical trials and animal models with non-steroidal anti-inflammatory drugs (NSAIDs) indicate that these drugs may decrease the risk of developing AD and apparently reduce Aβ deposition. Finally, further studies are needed to determine whether treatment with anti-inflammatory strategies, may decrease the neurodegenerative process that affects these patients.
Collapse
Affiliation(s)
- Marco A Meraz-Ríos
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados Mexico City, Mexico
| | | | | | | | | |
Collapse
|
35
|
Shastri A, Bonifati DM, Kishore U. Innate immunity and neuroinflammation. Mediators Inflamm 2013; 2013:342931. [PMID: 23843682 PMCID: PMC3697414 DOI: 10.1155/2013/342931] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/15/2013] [Indexed: 01/07/2023] Open
Abstract
Inflammation of central nervous system (CNS) is usually associated with trauma and infection. Neuroinflammation occurs in close relation to trauma, infection, and neurodegenerative diseases. Low-level neuroinflammation is considered to have beneficial effects whereas chronic neuroinflammation can be harmful. Innate immune system consisting of pattern-recognition receptors, macrophages, and complement system plays a key role in CNS homeostasis following injury and infection. Here, we discuss how innate immune components can also contribute to neuroinflammation and neurodegeneration.
Collapse
Affiliation(s)
- Abhishek Shastri
- Centre for Infection, Immunity and Disease Mechanisms, Heinz Wolff Building, Brunel University, London UB8 3PH, UK
| | - Domenico Marco Bonifati
- Unit of Neurology, Department of Neurological Disorders, Santa Chiara Hospital, Largo Medaglie d'oro 1, 38100 Trento, Italy
| | - Uday Kishore
- Centre for Infection, Immunity and Disease Mechanisms, Heinz Wolff Building, Brunel University, London UB8 3PH, UK
| |
Collapse
|
36
|
Zabel MK, Kirsch WM. From development to dysfunction: microglia and the complement cascade in CNS homeostasis. Ageing Res Rev 2013; 12:749-56. [PMID: 23419464 DOI: 10.1016/j.arr.2013.02.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 01/26/2013] [Accepted: 02/07/2013] [Indexed: 10/27/2022]
Abstract
Of the many mysteries that surround the brain, few surpass the awe-inspiring complexity of its development. The intricate wiring of the brain at both the system and molecular level is both spatially and temporally regulated in perfect synchrony. How such a delicate, yet elegant, system arises from an embryo's most basic cells remains at the forefront of neuroscientific research. At the cellular level, the competitive dance between synapses struggling to gain dominance seems to be refereed by both neurons themselves and microglia, the innate immune cells of the nervous system. Additionally, the unexpected complement cascade, a major effecter arm of the innate immune system, is almost certainly involved in synaptic remodeling by tagging destined neurons and synapses for destruction. As suddenly as they appear, the mechanisms of neurogenesis recede entering into adulthood. However, with age and insult, these mechanisms boisterously return, resulting in neurodegeneration. This review describes some of the mechanisms involved in synaptogenesis and wiring of the brain from the point of view of the innate immune system and then covers how similar molecular processes return with age and disease, specifically in the context of Alzheimer's disease.
Collapse
|
37
|
Fu H, Liu B, Frost JL, Hong S, Jin M, Ostaszewski B, Shankar GM, Costantino IM, Carroll MC, Mayadas TN, Lemere CA. Complement component C3 and complement receptor type 3 contribute to the phagocytosis and clearance of fibrillar Aβ by microglia. Glia 2012; 60:993-1003. [PMID: 22438044 PMCID: PMC3325361 DOI: 10.1002/glia.22331] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 02/28/2012] [Indexed: 11/08/2022]
Abstract
Complement components and their receptors are found within and around amyloid β (Aβ) cerebral plaques in Alzheimer's disease (AD). Microglia defend against pathogens through phagocytosis via complement component C3 and/or engagement of C3 cleavage product iC3b with complement receptor type 3 (CR3, Mac-1). Here, we provide direct evidence that C3 and Mac-1 mediate, in part, phagocytosis and clearance of fibrillar amyloid-β (fAβ) by murine microglia in vitro and in vivo. Microglia took up not only synthetic fAβ(42) but also amyloid cores from patients with AD, transporting them to lysosomes in vitro. Fibrillar Aβ(42) uptake was significantly attenuated by the deficiency or knockdown of C3 or Mac-1 and scavenger receptor class A ligands. In addition, C3 or Mac-1 knockdown combined with a scavenger receptor ligand, fucoidan, further attenuated fibrillar Aβ(42) uptake by N9 microglia. Fluorescent fibrillar Aβ(42) microinjected cortically was significantly higher in C3 and Mac-1 knockout mice compared with wild-type mice 5 days after surgery, indicating reduced clearance in vivo. Together, these results demonstrate that C3 and Mac-1 are involved in phagocytosis and clearance of fAβ by microglia, providing support for a potential beneficial role for microglia and the complement system in AD pathogenesis. © 2012 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Hongjun Fu
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Bin Liu
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Jeffrey L. Frost
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Soyon Hong
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Ming Jin
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Beth Ostaszewski
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Ganesh M. Shankar
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Isabel M. Costantino
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | | | - Tanya N. Mayadas
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Cynthia A. Lemere
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| |
Collapse
|
38
|
Osera C, Pascale A, Amadio M, Venturini L, Govoni S, Ricevuti G. Pentraxins and Alzheimer's disease: at the interface between biomarkers and pharmacological targets. Ageing Res Rev 2012; 11:189-98. [PMID: 22186030 DOI: 10.1016/j.arr.2011.12.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 11/21/2011] [Accepted: 12/06/2011] [Indexed: 01/01/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder involving deposition of misfolded proteins in vulnerable brain regions leading to inexorable and progressive neuronal loss and deterioration of cognitive functions. The AD brain displays features typical of chronic inflammation as defined by the presence of activated microglia and by an excessive amount of neuroinflammatory components such as cytokines and acute-phase proteins. This review aims to shed light on the role of the immune processes involved in AD, focusing on a family of inflammatory modulators belonging to the acute-phase proteins and crucial components of the humoral arm of innate immunity: pentraxins. In particular we analyze function of the pentraxins in AD, their upregulation in the brain and their contribution to neurodegeneration. Additionally, we highlight the role of pentraxins as putative AD biomarkers and as pharmacological therapeutic targets.
Collapse
Affiliation(s)
- Cecilia Osera
- Department of Drug Sciences, Section of Pharmacology, Laboratory of Neurobiology and Neuropharmacology of Neurodegenerative Diseases and the Nervous System, University of Pavia, Italy.
| | | | | | | | | | | |
Collapse
|
39
|
Floden AM, Combs CK. Microglia demonstrate age-dependent interaction with amyloid-β fibrils. J Alzheimers Dis 2011; 25:279-93. [PMID: 21403390 DOI: 10.3233/jad-2011-101014] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Alzheimer's disease (AD) is an age-associated disease characterized by increased accumulation of extracellular amyloid-β (Aβ) plaques within the brain. Histological examination has also revealed profound microglial activation in diseased brains often in association with these fibrillar peptide aggregates. The paradoxical presence of increased, reactive microglia yet accumulating extracellular debris suggests that these cells may be phagocytically compromised during disease. Prior work has demonstrated that primary microglia from adult mice are unable to phagocytose fibrillar Aβ1-42 in vitro when compared to microglia cultured from early postnatal animals. These data suggest that microglia undergo an age-associated decrease in microglial ability to interact with Aβ fibrils. In order to better define a temporal profile of microglia-Aβ interaction, acutely isolated, rather than cultured, microglia from 2 month, 6 month, and postnatal day 0 C57BL/6 mice were compared. Postnatal day 0 microglia demonstrated a CD47 dependent ability to phagocytose Aβ fibrils that was lost by 6 months. This corresponded with the ability of postnatal day 0 but not adult microglia to decrease Aβ immunoreactive plaque load from AD sections in vitro. In spite of limited Aβ uptake ability, adult microglia had functional phagocytic uptake of bacterial bioparticles and demonstrated the ability to adhere to both Aβ plaques and in vitro fibrillized Aβ. These data demonstrate a temporal profile of specifically Aβ-microglia interaction with a critical developmental period at 6 months in which cells remain able to interact with Aβ fibrils but lose their ability to phagocytose it.
Collapse
Affiliation(s)
- Angela Marie Floden
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203-9037, USA
| | | |
Collapse
|
40
|
Huntington's Disease: An Immune Perspective. Neurol Res Int 2011; 2011:563784. [PMID: 21876800 PMCID: PMC3163125 DOI: 10.1155/2011/563784] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 03/31/2011] [Accepted: 05/12/2011] [Indexed: 01/28/2023] Open
Abstract
Huntington's disease (HD) is a progressive neurodegenerative disorder that is caused by abnormal expansion of CAG trinucleotide repeats. Neuroinflammation is a typical feature of most neurodegenerative diseases that leads to an array of pathological changes within the affected areas in the brain. The neurodegeneration in HD is also caused by aberrant immune response in the presence of aggregated mutant huntingtin protein. The effects of immune activation in HD nervous system are a relatively unexplored area of research. This paper summarises immunological features associated with development and progression of HD.
Collapse
|
41
|
Abstract
Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed "resting microglia." Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the "activated microglial cell." This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.
Collapse
|
42
|
Bruban J, Maoui A, Chalour N, An N, Jonet L, Feumi C, Tréton J, Sennlaub F, Behar-Cohen F, Mascarelli F, Dinet V. CCR2/CCL2-mediated inflammation protects photoreceptor cells from amyloid-β-induced apoptosis. Neurobiol Dis 2011; 42:55-72. [PMID: 21220018 DOI: 10.1016/j.nbd.2011.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 12/22/2010] [Accepted: 01/02/2011] [Indexed: 12/24/2022] Open
Abstract
Age-related macular degeneration is characterized by the formation of drusen containing amyloid-β (Aβ) and the degeneration of photoreceptors. To explore the largely unknown role of Aβ in the retina, we investigated the effects on photoreceptors of the oligomeric form of Aβ(1-42). Subretinal injection of the Aβ peptide induced misplaced expression of recoverin and synaptophysin in the photoreceptors, oxidative stress in their inner and outer segments, and finally apoptosis. Aβ did not induce cell death in purified photoreceptor cell cultures, but did so in retinal cell cultures, thereby suggesting that the cellular environment plays a role in Aβ-induced photoreceptor apoptosis. Subretinal injection of Aβ was followed by activation and migration of microglial cells and then by photoreceptor apoptosis. Microglial cells phagocytosed rhodopsin-containing debris and Aβ in the subretinal space. Quantitative RT-PCR allowed us to identify a specific gene expression profile associated with the Aβ-induced progression of retinal degeneration and consistent with oxidative stress, inflammation, and an apoptotic program. The gene most highly upregulated in Aβ-injected retinas was that for the chemokine CCL2, and its absence or that of its cognate receptor CCR2 greatly reduced migration of activated microglial cells to the site of retinal injury and profoundly worsened photoreceptor degeneration and disorganization of the retinal pigment epithelium in Aβ-injected retinas. Our study pinpoints the roles of Aβ and of CCL2/CCR2 axis-dependent inflammation in photoreceptor apoptosis.
Collapse
Affiliation(s)
- Julien Bruban
- Centre de Recherche des Cordeliers, Université Pierre et Marie Curie-Paris6, UMRS 872, F-75006 Paris, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Norepinephrine promotes microglia to uptake and degrade amyloid beta peptide through upregulation of mouse formyl peptide receptor 2 and induction of insulin-degrading enzyme. J Neurosci 2010; 30:11848-57. [PMID: 20810904 DOI: 10.1523/jneurosci.2985-10.2010] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Locus ceruleus (LC) is the main subcortical site of norepinephrine synthesis. In Alzheimer's disease (AD) patients and rodent models, degeneration of LC neurons and reduced levels of norepinephrine in LC projection areas are significantly correlated with the increase in amyloid plaques, neurofibrillary tangles, and severity of dementia. Activated microglia play a pivotal role in the progression of AD by either clearing amyloid beta peptide (Abeta) deposits through uptake of Abeta or releasing cytotoxic substances and proinflammatory cytokines. Here, we investigated the effect of norepinephrine on Abeta uptake and clearance by murine microglia and explored the underlying mechanisms. We found that murine microglia cell line N9 and primary microglia expressed beta(2) adrenergic receptor (AR) but not beta(1) and beta(3)AR. Norepinephrine and isoproterenol upregulated the expression of Abeta receptor mFPR2, a mouse homolog of human formyl peptide receptor FPR2, through activation of beta(2)AR in microglia. Norepinephrine also induced mFPR2 expression in mouse brain. Activation of beta(2)AR in microglia promoted Abeta(42) uptake through upregulation of mFPR2 and enhanced spontaneous cell migration but had no effect on cell migration in response to mFPR2 agonists. Furthermore, activation of beta(2)AR on microglia induced the expression of insulin-degrading enzyme and increased the degradation of Abeta(42). Mechanistic studies showed that isoproterenol induced mFPR2 expression through ERK1/2-NF-kappaB and p38-NF-kappaB signaling pathways. These findings suggest that noradrenergic innervation from LC is needed to maintain adequate Abeta uptake and clearance by microglia, and norepinephrine is a link between neuron and microglia to orchestrate the host response to Abeta in AD.
Collapse
|
44
|
Trafficking CD11b-positive blood cells deliver therapeutic genes to the brain of amyloid-depositing transgenic mice. J Neurosci 2010; 30:9651-8. [PMID: 20660248 DOI: 10.1523/jneurosci.0329-10.2010] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A major question for gene therapy in brain concerns methods to administer therapeutic genes in a uniform manner over major portions of the brain. A second question in neuroimmunology concerns the extent to which monocytes migrate to the CNS in degenerative disorders. Here we show that CD11b+ cells (largely monocytes) isolated from the bone marrow of GFP (green fluorescent protein)-expressing donors spontaneously home to compacted amyloid plaques in the brain. Injections of these cells as a single pulse show a rapid clearance from circulation (90 min half-life) and tissue residence half-lives of approximately 3 d. The uptake into brain was minimal in nontransgenic mice. In transgenic mice containing amyloid deposits, uptake was dramatically increased and associated with a corresponding decrease in monocyte uptake into peripheral organs compared to nontransgenic littermates. Twice weekly infusions of the CD11b+ bone marrow cells transfected with a genetically engineered form of the protease neprilysin completely arrest amyloid deposition in an aggressively depositing transgenic model. Exploiting the natural homing properties of peripherally derived blood cells to deliver therapeutic genes has the advantages of access to the entire CNS, expression largely restricted to sites of injury, low risk of immune reactivity, and fading of expression if adverse reactions are encountered. These observations support the feasibility of testing autologous monocytes for application of therapeutic genes in human CNS disease. Moreover, these data support the results from bone marrow grafts that circulating CD11b+ cells can enter the CNS without requiring the use of lethal irradiation.
Collapse
|
45
|
Lee CYD, Landreth GE. The role of microglia in amyloid clearance from the AD brain. J Neural Transm (Vienna) 2010; 117:949-60. [PMID: 20552234 DOI: 10.1007/s00702-010-0433-4] [Citation(s) in RCA: 470] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 05/26/2010] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD), the most prominent cause of senile dementia, is clinically characterized by the extracellular deposition of beta-amyloid (Abeta) and the intracellular neurofibrillary tangles. It has been well accepted that AD pathogenesis arises from perturbation in the homeostasis of Abeta in the brain. Abeta is normally produced at high levels in the brain and cleared in an equivalent rate. Thus, even a moderate decrease in the clearance leads to the accumulation of Abeta and subsequent amyloid deposition. Microglia are the tissue macrophages in the central nervous system (CNS) and have been shown to play major roles in internalization and degradation of Abeta. Abeta exists in the brain both in soluble and in fibrillar forms. Microglia interact with these two forms of Abeta in different ways. They take up soluble forms of Abeta through macropinocytosis and LDL receptor-related proteins (LRPs) mediated pathway. Fibrillar forms of Abeta interact with the cell surface innate immune receptor complex, initiating intracellular signaling cascades that stimulate phagocytosis. Inflammatory responses influence the activation status of microglia and subsequently regulate their ability to take up and degrade Abeta. ApoE and its receptors have been shown to play critical roles in these processes. In this review, we will explore the mechanisms that microglia utilize to clear Abeta and the effectors that modulate the processes.
Collapse
Affiliation(s)
- C Y Daniel Lee
- School of Medicine, Case Western Reserve University, SOM E649, 10900 Euclid Avenue, Cleveland, OH 44106-4928, USA.
| | | |
Collapse
|
46
|
Frautschy SA, Cole GM. Why pleiotropic interventions are needed for Alzheimer's disease. Mol Neurobiol 2010; 41:392-409. [PMID: 20437209 PMCID: PMC2876259 DOI: 10.1007/s12035-010-8137-1] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 04/06/2010] [Indexed: 01/19/2023]
Abstract
Alzheimer's disease (AD) involves a complex pathological cascade thought to be initially triggered by the accumulation of beta-amyloid (Abeta) peptide aggregates or aberrant amyloid precursor protein (APP) processing. Much is known of the factors initiating the disease process decades prior to the onset of cognitive deficits, but an unclear understanding of events immediately preceding and precipitating cognitive decline is a major factor limiting the rapid development of adequate prevention and treatment strategies. Multiple pathways are known to contribute to cognitive deficits by disruption of neuronal signal transduction pathways involved in memory. These pathways are altered by aberrant signaling, inflammation, oxidative damage, tau pathology, neuron loss, and synapse loss. We need to develop stage-specific interventions that not only block causal events in pathogenesis (aberrant tau phosphorylation, Abeta production and accumulation, and oxidative damage), but also address damage from these pathways that will not be reversed by targeting prodromal pathways. This approach would not only focus on blocking early events in pathogenesis, but also adequately correct for loss of synapses, substrates for neuroprotective pathways (e.g., docosahexaenoic acid), defects in energy metabolism, and adverse consequences of inappropriate compensatory responses (aberrant sprouting). Monotherapy targeting early single steps in this complicated cascade may explain disappointments in trials with agents inhibiting production, clearance, or aggregation of the initiating Abeta peptide or its aggregates. Both plaque and tangle pathogenesis have already reached AD levels in the more vulnerable brain regions during the "prodromal" period prior to conversion to "mild cognitive impairment (MCI)." Furthermore, many of the pathological events are no longer proceeding in series, but are going on in parallel. By the MCI stage, we stand a greater chance of success by considering pleiotropic drugs or cocktails that can independently limit the parallel steps of the AD cascade at all stages, but that do not completely inhibit the constitutive normal functions of these pathways. Based on this hypothesis, efforts in our laboratories have focused on the pleiotropic activities of omega-3 fatty acids and the anti-inflammatory, antioxidant, and anti-amyloid activity of curcumin in multiple models that cover many steps of the AD pathogenic cascade (Cole and Frautschy, Alzheimers Dement 2:284-286, 2006).
Collapse
Affiliation(s)
- Sally A Frautschy
- Geriatric Research and Clinical Center, Greater Los Angeles Healthcare System, Veteran's Administration, Los Angeles, USA.
| | | |
Collapse
|
47
|
Fraser DA, Pisalyaput K, Tenner AJ. C1q enhances microglial clearance of apoptotic neurons and neuronal blebs, and modulates subsequent inflammatory cytokine production. J Neurochem 2009; 112:733-43. [PMID: 19919576 DOI: 10.1111/j.1471-4159.2009.06494.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The expression of C1q, a recognition molecule of the complement system, is up-regulated following neuronal injury and is detected early in neurodegenerative disorders such as Alzheimer's disease. This multimeric protein triggers an enhancement of phagocytosis of suboptimally opsonized targets by microglia, the phagocytic cells of the CNS, similar to other phagocytes, enhances the uptake of apoptotic cells in peripheral phagocytes, and suppresses inflammatory cytokine production in human monocytes, macrophages and dendritic cells in the absence of activation of the entire complement cascade. The goal of this study was to determine if C1q could influence the inflammatory response to injury in the CNS, using primary rat microglia and neurons. The data show that microglia preferentially ingest apoptotic cells in comparison to live cells, like other professional phagocytes, that microglial ingestion of apoptotic neurons and neuronal blebs is enhanced by the presence of normal serum and that these enhanced levels of uptake are diminished in serum depleted of C1q. In addition, purified C1q bound to apoptotic neurons and neuronal blebs in a dose dependent manner, and alone triggered a significant enhancement of uptake by microglia. Microglia added to C1q coated wells or fed apoptotic neurons or neuronal blebs coated with C1q suppressed the lipopolysaccharide-induced production of proinflammatory cytokines interleukin (IL)-1alpha, IL-1beta, IL-6 and TNF-alpha, while the presence of C1q enhanced levels of the chemokine MCP-1/CCL2. The data are consistent with a protective role for C1q in the CNS during early stages of cell death by enhancing microglial clearance of apoptotic cells and suppressing proinflammatory cytokines.
Collapse
Affiliation(s)
- Deborah A Fraser
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697-3900, USA.
| | | | | |
Collapse
|
48
|
Jakob-Roetne R, Jacobsen H. Alzheimer's disease: from pathology to therapeutic approaches. Angew Chem Int Ed Engl 2009; 48:3030-59. [PMID: 19330877 DOI: 10.1002/anie.200802808] [Citation(s) in RCA: 485] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mind how you go: The current strategies for the development of therapies for Alzheimer's disease are very diverse. Particular attention is given to the search for inhibitors (see picture for two examples) of the proteolytic enzyme beta- and gamma-secretase, which inhibits the cleavage of the amyloid precursor proteins into amyloid beta peptides, from which the disease-defining deposits of plaque in the brains of Alzheimer's patients originates.Research on senile dementia and Alzheimer's disease covers an extremely broad range of scientific activities. At the recent international meeting of the Alzheimer's Association (ICAD 2008, Chicago) more than 2200 individual scientific contributions were presented. The aim of this Review is to give an overview of the field and to outline its main areas, starting from behavioral abnormalities and visible pathological findings and then focusing on the molecular details of the pathology. The "amyloid hypothesis" of Alzheimer's disease is given particular attention, since the majority of the ongoing therapeutic approaches are based on its theoretical framework.
Collapse
Affiliation(s)
- Roland Jakob-Roetne
- F.Hoffmann-La Roche AG, Medicinal Chemistry, Bldg 92/8.10B, 4070 Basel, Switzerland.
| | | |
Collapse
|
49
|
Jakob-Roetne R, Jacobsen H. Die Alzheimer-Demenz: von der Pathologie zu therapeutischen Ansätzen. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200802808] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
50
|
Tahtouh M, Croq F, Vizioli J, Sautiere PE, Van Camp C, Salzet M, Daha MR, Pestel J, Lefebvre C. Evidence for a novel chemotactic C1q domain-containing factor in the leech nerve cord. Mol Immunol 2009; 46:523-31. [DOI: 10.1016/j.molimm.2008.07.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 07/15/2008] [Accepted: 07/15/2008] [Indexed: 10/21/2022]
|