1
|
Sfera A, Rahman L, Zapata-Martín Del Campo CM, Kozlakidis Z. Long COVID as a Tauopathy: Of "Brain Fog" and "Fusogen Storms". Int J Mol Sci 2023; 24:12648. [PMID: 37628830 PMCID: PMC10454863 DOI: 10.3390/ijms241612648] [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: 07/13/2023] [Revised: 08/04/2023] [Accepted: 08/06/2023] [Indexed: 08/27/2023] Open
Abstract
Long COVID, also called post-acute sequelae of SARS-CoV-2, is characterized by a multitude of lingering symptoms, including impaired cognition, that can last for many months. This symptom, often called "brain fog", affects the life quality of numerous individuals, increasing medical complications as well as healthcare expenditures. The etiopathogenesis of SARS-CoV-2-induced cognitive deficit is unclear, but the most likely cause is chronic inflammation maintained by a viral remnant thriving in select body reservoirs. These viral sanctuaries are likely comprised of fused, senescent cells, including microglia and astrocytes, that the pathogen can convert into neurotoxic phenotypes. Moreover, as the enteric nervous system contains neurons and glia, the virus likely lingers in the gastrointestinal tract as well, accounting for the intestinal symptoms of long COVID. Fusogens are proteins that can overcome the repulsive forces between cell membranes, allowing the virus to coalesce with host cells and enter the cytoplasm. In the intracellular compartment, the pathogen hijacks the actin cytoskeleton, fusing host cells with each other and engendering pathological syncytia. Cell-cell fusion enables the virus to infect the healthy neighboring cells. We surmise that syncytia formation drives cognitive impairment by facilitating the "seeding" of hyperphosphorylated Tau, documented in COVID-19. In our previous work, we hypothesized that the SARS-CoV-2 virus induces premature endothelial senescence, increasing the permeability of the intestinal and blood-brain barrier. This enables the migration of gastrointestinal tract microbes and/or their components into the host circulation, eventually reaching the brain where they may induce cognitive dysfunction. For example, translocated lipopolysaccharides or microbial DNA can induce Tau hyperphosphorylation, likely accounting for memory problems. In this perspective article, we examine the pathogenetic mechanisms and potential biomarkers of long COVID, including microbial cell-free DNA, interleukin 22, and phosphorylated Tau, as well as the beneficial effect of transcutaneous vagal nerve stimulation.
Collapse
Affiliation(s)
- Adonis Sfera
- Paton State Hospital, 3102 Highland Ave, Patton, CA 92369, USA
- School of Behavioral Health, Loma Linda University, 11139 Anderson St., Loma Linda, CA 92350, USA
- Department of Psychiatry, University of California, Riverside 900 University Ave, Riverside, CA 92521, USA
| | - Leah Rahman
- Department of Neuroscience, University of Oregon, 222 Huestis Hall, Eugene, OR 97401, USA
| | | | - Zisis Kozlakidis
- International Agency for Research on Cancer, World Health Organization, 69000 Lyon, France
| |
Collapse
|
2
|
Dovonou A, Bolduc C, Soto Linan V, Gora C, Peralta Iii MR, Lévesque M. Animal models of Parkinson's disease: bridging the gap between disease hallmarks and research questions. Transl Neurodegener 2023; 12:36. [PMID: 37468944 PMCID: PMC10354932 DOI: 10.1186/s40035-023-00368-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/19/2023] [Indexed: 07/21/2023] Open
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms. More than 200 years after its first clinical description, PD remains a serious affliction that affects a growing proportion of the population. Prevailing treatments only alleviate symptoms; there is still neither a cure that targets the neurodegenerative processes nor therapies that modify the course of the disease. Over the past decades, several animal models have been developed to study PD. Although no model precisely recapitulates the pathology, they still provide valuable information that contributes to our understanding of the disease and the limitations of our treatment options. This review comprehensively summarizes the different animal models available for Parkinson's research, with a focus on those induced by drugs, neurotoxins, pesticides, genetic alterations, α-synuclein inoculation, and viral vector injections. We highlight their characteristics and ability to reproduce PD-like phenotypes. It is essential to realize that the strengths and weaknesses of each model and the induction technique at our disposal are determined by the research question being asked. Our review, therefore, seeks to better aid researchers by ensuring a concrete discernment of classical and novel animal models in PD research.
Collapse
Affiliation(s)
- Axelle Dovonou
- CERVO Brain Research Centre, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Cyril Bolduc
- CERVO Brain Research Centre, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Victoria Soto Linan
- CERVO Brain Research Centre, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Charles Gora
- CERVO Brain Research Centre, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Modesto R Peralta Iii
- CERVO Brain Research Centre, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Martin Lévesque
- CERVO Brain Research Centre, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada.
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Université Laval, Québec, QC, Canada.
| |
Collapse
|
3
|
Park JH, Hwang JW, Lee HJ, Jang GM, Jeong YJ, Cho J, Seo J, Hoe HS. Lomerizine inhibits LPS-mediated neuroinflammation and tau hyperphosphorylation by modulating NLRP3, DYRK1A, and GSK3α/β. Front Immunol 2023; 14:1150940. [PMID: 37435081 PMCID: PMC10331167 DOI: 10.3389/fimmu.2023.1150940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 06/05/2023] [Indexed: 07/13/2023] Open
Abstract
Introduction Lomerizine is a calcium channel blocker that crosses the blood-brain barrier and is used clinically in the treatment of migraines. However, whether lomerizine is beneficial in modulating neuroinflammatory responses has not been tested yet. Methods To assess the potential of lomerizine for repurposing as a treatment for neuroinflammation, we investigated the effects of lomerizine on LPS-induced proinflammatory responses in BV2 microglial cells, Alzheimer's disease (AD) excitatory neurons differentiated from induced pluripotent stem cells (iPSCs), and in LPS-treated wild type mice. Results In BV2 microglial cells, lomerizine pretreatment significantly reduced LPS-evoked proinflammatory cytokine and NLRP3 mRNA levels. Similarly, lomerizine pretreatment significantly suppressed the increases in Iba-1, GFAP, proinflammatory cytokine and NLRP3 expression induced by LPS in wild-type mice. In addition, lomerizine posttreatment significantly decreased LPS-stimulated proinflammatory cytokine and SOD2 mRNA levels in BV2 microglial cells and/or wild-type mice. In LPS-treated wild-type mice and AD excitatory neurons differentiated from iPSCs, lomerizine pretreatment ameliorated tau hyperphosphorylation. Finally, lomerizine abolished the LPS-mediated activation of GSK3α/β and upregulation of DYRK1A, which is responsible for tau hyperphosphorylation, in wild-type mice. Discussion These data suggest that lomerizine attenuates LPS-mediated neuroinflammatory responses and tau hyperphosphorylation and is a potential drug for neuroinflammation- or tauopathy-associated diseases.
Collapse
Affiliation(s)
- Jin-Hee Park
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea
| | - Jeong-Woo Hwang
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Hyun-ju Lee
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Geum Mi Jang
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea
| | - Yoo Joo Jeong
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea
| | - Joonho Cho
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea
| | - Jinsoo Seo
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea
| | - Hyang-Sook Hoe
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea
| |
Collapse
|
4
|
Kim J, Kim SJ, Jeong HR, Park JH, Moon M, Hoe HS. Inhibiting EGFR/HER-2 ameliorates neuroinflammatory responses and the early stage of tau pathology through DYRK1A. Front Immunol 2022; 13:903309. [PMID: 36341365 PMCID: PMC9632417 DOI: 10.3389/fimmu.2022.903309] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 10/03/2022] [Indexed: 11/29/2022] Open
Abstract
The FDA-approved EGFR/HER2 inhibitor varlitinib inhibits tumor growth and is used in cancer treatment. However, the neuroinflammatory response associated with EGFR/HER2 and its underlying mechanism have not been elucidated. This study evaluates the impact of varlitinib on LPS- and tau-mediated neuroinflammatory responses for the first time. In BV2 microglial cells, varlitinib reduced LPS-stimulated il-1β and/or inos mRNA levels and downstream AKT/FAK/NF-kB signaling. Importantly, varlitinib significantly diminished LPS-mediated microglial nlrp3 inflammasome activation in BV2 microglial cells. In primary astrocytes, varlitinib downregulated LPS-evoked astroglial il-1β mRNA levels, AKT signaling, and nlrp3 inflammasome activation. In LPS-treated wild-type mice, varlitinib significantly reduced LPS-stimulated glial activation and IL-1β/NLRP3 inflammasome formation. Moreover, varlitinib significantly reduced micro- and astroglial activation and tau hyperphosphorylation in 3-month-old tau-overexpressing PS19 mice by downregulating tau kinase DYRK1A levels. However, in 6-month-old tau-overexpressing PS19 mice, varlitinib only significantly diminished astroglial activation and tau phosphorylation at Thr212/Ser214. Taken together, our findings suggest that varlitinib has therapeutic potential for LPS- and tau-induced neuroinflammatory responses and the early stages of tau pathology.
Collapse
Affiliation(s)
- Jieun Kim
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Su-Jin Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Ha-Ram Jeong
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Jin-Hee Park
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, South Korea
| | - Minho Moon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
- *Correspondence: Hyang-Sook Hoe, ; Minho Moon,
| | - Hyang-Sook Hoe
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, South Korea
- *Correspondence: Hyang-Sook Hoe, ; Minho Moon,
| |
Collapse
|
5
|
Kim J, Lee HJ, Park JH, Cha BY, Hoe HS. Nilotinib modulates LPS-induced cognitive impairment and neuroinflammatory responses by regulating P38/STAT3 signaling. J Neuroinflammation 2022; 19:187. [PMID: 35841100 PMCID: PMC9288088 DOI: 10.1186/s12974-022-02549-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 07/05/2022] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND In chronic myelogenous leukemia, reciprocal translocation between chromosome 9 and chromosome 22 generates a chimeric protein, Bcr-Abl, that leads to hyperactivity of tyrosine kinase-linked signaling transduction. The therapeutic agent nilotinib inhibits Bcr-Abl/DDR1 and can cross the blood-brain barrier, but its potential impact on neuroinflammatory responses and cognitive function has not been studied in detail. METHODS The effects of nilotinib in vitro and in vivo were assessed by a combination of RT-PCR, real-time PCR, western blotting, ELISA, immunostaining, and/or subcellular fractionation. In the in vitro experiments, the effects of 200 ng/mL LPS or PBS on BV2 microglial cells, primary microglia or primary astrocytes pre- or post-treated with 5 µM nilotinib or vehicle were evaluated. The in vivo experiments involved wild-type mice administered a 7-day course of daily injections with 20 mg/kg nilotinib (i.p.) or vehicle before injection with 10 mg/kg LPS (i.p.) or PBS. RESULTS In BV2 microglial cells, pre- and post-treatment with nilotinib altered LPS-induced proinflammatory/anti-inflammatory cytokine mRNA levels by suppressing AKT/P38/SOD2 signaling. Nilotinib treatment also significantly downregulated LPS-stimulated proinflammatory cytokine levels in primary microglia and primary astrocytes by altering P38/STAT3 signaling. Experiments in wild-type mice showed that nilotinib administration affected LPS-mediated microglial/astroglial activation in a brain region-specific manner in vivo. In addition, nilotinib significantly reduced proinflammatory cytokine IL-1β, IL-6 and COX-2 levels and P38/STAT3 signaling in the brain in LPS-treated wild-type mice. Importantly, nilotinib treatment rescued LPS-mediated spatial working memory impairment and cortical dendritic spine number in wild-type mice. CONCLUSIONS Our results indicate that nilotinib can modulate neuroinflammatory responses and cognitive function in LPS-stimulated wild-type mice.
Collapse
Affiliation(s)
- Jieun Kim
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Korea
| | - Hyun-Ju Lee
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Korea
| | - Jin-Hee Park
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Korea.,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, 42988, Korea
| | - Byung-Yoon Cha
- PharmacoRex Co., Ltd., 20 Techno 1-ro, Yuseong-gu, Daejeon, 34016, Korea
| | - Hyang-Sook Hoe
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Korea. .,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, 42988, Korea.
| |
Collapse
|
6
|
Abstract
Systemic inflammation elicited by sepsis can induce an acute cerebral dysfunction known as sepsis-associated encephalopathy (SAE). Recent evidence suggests that SAE is common but shows a dynamic trajectory over time. Half of all patients with sepsis develop SAE in the intensive care unit, and some survivors present with sustained cognitive impairments for several years after initial sepsis onset. It is not clear why some, but not all, patients develop SAE and also the factors that determine the persistence of SAE. Here, we first summarize the chronic pathology and the dynamic changes in cognitive functions seen after the onset of sepsis. We then outline the cerebral effects of sepsis, such as neuroinflammation, alterations in neuronal synapses and neurovascular changes. We discuss the key factors that might contribute to the development and persistence of SAE in older patients, including premorbid neurodegenerative pathology, side effects of sedatives, renal dysfunction and latent virus reactivation. Finally, we postulate that some of the mechanisms that underpin neuropathology in SAE may also be relevant to delirium and persisting cognitive impairments that are seen in patients with severe COVID-19.
Collapse
Affiliation(s)
- Tatsuya Manabe
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Michael T Heneka
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Bonn, Germany.
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
- Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, USA.
| |
Collapse
|
7
|
Hulse J, Bhaskar K. Crosstalk Between the NLRP3 Inflammasome/ASC Speck and Amyloid Protein Aggregates Drives Disease Progression in Alzheimer's and Parkinson's Disease. Front Mol Neurosci 2022; 15:805169. [PMID: 35185469 PMCID: PMC8850380 DOI: 10.3389/fnmol.2022.805169] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/11/2022] [Indexed: 12/14/2022] Open
Abstract
Two key pathological hallmarks of neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD), are the accumulation of misfolded protein aggregates and the chronic progressive neuroinflammation that they trigger. Numerous original research and reviews have provided a comprehensive understanding of how aggregated proteins (amyloid β, pathological tau, and α-synuclein) contribute to the disease, including driving sterile inflammation, in part, through the aggregation of multi-protein inflammasome complexes and the ASC speck [composed of NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3), Apoptosis-associated speck-like protein containing a C-terminal caspase activation and recruitment domain (ASC), and inflammatory caspase-1] involved in innate immunity. Here, we provide a unique perspective on the crosstalk between the aggregation-prone proteins involved in AD/PD and the multi-protein inflammasome complex/ASC speck that fuels feed-forward exacerbation of each other, driving neurodegeneration. Failed turnover of protein aggregates (both AD/PD related aggregates and the ASC speck) by protein degradation pathways, prionoid propagation of inflammation by the ASC speck, cross-seeding of protein aggregation by the ASC speck, and pro-aggregatory cleavage of proteins by caspase-1 are some of the mechanisms that exacerbate disease progression. We also review studies that provide this causal framework and highlight how the ASC speck serves as a platform for the propagation and spreading of inflammation and protein aggregation that drives AD and PD.
Collapse
Affiliation(s)
- Jonathan Hulse
- Department of Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, NM, United States
| | - Kiran Bhaskar
- Department of Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, NM, United States,Department of Neurology, University of New Mexico, Albuquerque, NM, United States,*Correspondence: Kiran Bhaskar,
| |
Collapse
|
8
|
Fronza MG, Baldinotti R, Fetter J, Rosa SG, Sacramento M, Nogueira CW, Alves D, Praticò D, Savegnago L. Beneficial effects of QTC-4-MeOBnE in an LPS-induced mouse model of depression and cognitive impairments: The role of blood-brain barrier permeability, NF-κB signaling, and microglial activation. Brain Behav Immun 2022; 99:177-191. [PMID: 34624485 DOI: 10.1016/j.bbi.2021.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 09/29/2021] [Accepted: 10/01/2021] [Indexed: 12/11/2022] Open
Abstract
Clinical and preclinical investigations have suggested a possible biological link betweenmajor depressive disorder (MDD) and Alzheimer's disease (AD). Therefore, a pharmacologic approach to treating MDD could be envisioned as a preventative therapy for some AD cases. In line with this, 1-(7-chloroquinolin-4-yl)-N-(4-methoxybenzyl)-5-methyl-1H-1,2,3-triazole-4 carboxamide (QTC-4-MeOBnE) is characterized as an inhibitor of β-secretase, glycogen synthase kinase 3β, and acetylcholinesterase and has also shown secondary effects underlying the modulation of neurogenesis and synaptic plasticity pathways. Therefore, we investigated the effects of QTC-4-MeOBnE treatment (0.1 or 1 mg/kg) on depressive-like behavior and cognitive impairments elicited by repeated injections of lipopolysaccharide (LPS; 250 μg/kg) in mice. Injections of LPS for seven days led to memory impairments and depressive-like behavior, as evidenced in the Y-maze/object recognition test and forced swimming/splash tests, respectively. However, these impairments were prevented in mice that, after the last LPS injection, were also treated with QTC-4-MeOBnE (1 mg/kg). This effect was associated with restoring blood-brain barrier permeability, reducing oxidative/nitrosative biomarkers, and decreasing neuroinflammation mediated NF-κB signaling in the hippocampus and cortex of the mice. To further investigate the involvement with NF-κB signaling, we evaluated the effects of QTC-4-MeOBnE on microglial cell activation through canonical and non-canonical pathways and the modulation of the involved components. Together, our findings highlight the pharmacological benefits of QTC-4-MeOBnE in a mouse model of sickness behavior and memory impairments, supporting the novel concept that since this molecule produces anti-depressant activity, it could also be beneficial for preventing AD onset and related dementias in subjects suffering from MDD through inflammatory pathway modulation.
Collapse
Affiliation(s)
- Mariana G Fronza
- Neurobiotechnology Research Group (GPN) - Centre for Technology Development CDTec, Federal University of Pelotas (UFPel), Pelotas, RS, Brazil
| | - Rodolfo Baldinotti
- Neurobiotechnology Research Group (GPN) - Centre for Technology Development CDTec, Federal University of Pelotas (UFPel), Pelotas, RS, Brazil
| | - Jenifer Fetter
- Neurobiotechnology Research Group (GPN) - Centre for Technology Development CDTec, Federal University of Pelotas (UFPel), Pelotas, RS, Brazil
| | - Suzan Gonçalves Rosa
- Laboratory of Synthesis, Reactivity and Pharmacological and Toxicological Evaluation of Organocalcogens, Center for Natural and Exact Sciences, Federal University of Santa Maria, UFSM, Santa Maria, RS, Brazil
| | - Manoela Sacramento
- Laboratory of Clean Organic Synthesis (LASOL), Center for Chemical, Pharmaceutical and Food Sciences (CCQFA), UFPel, RS, Brazil
| | - Cristina Wayne Nogueira
- Laboratory of Synthesis, Reactivity and Pharmacological and Toxicological Evaluation of Organocalcogens, Center for Natural and Exact Sciences, Federal University of Santa Maria, UFSM, Santa Maria, RS, Brazil
| | - Diego Alves
- Laboratory of Clean Organic Synthesis (LASOL), Center for Chemical, Pharmaceutical and Food Sciences (CCQFA), UFPel, RS, Brazil
| | - Domenico Praticò
- Alzheimer's Center at Temple - ACT, Temple University, Lewis Katz School of Medicine, Philadelphia, PA, United States
| | - Lucielli Savegnago
- Neurobiotechnology Research Group (GPN) - Centre for Technology Development CDTec, Federal University of Pelotas (UFPel), Pelotas, RS, Brazil.
| |
Collapse
|
9
|
Kim HS, Kim S, Shin SJ, Park YH, Nam Y, Kim CW, Lee KW, Kim SM, Jung ID, Yang HD, Park YM, Moon M. Gram-negative bacteria and their lipopolysaccharides in Alzheimer's disease: pathologic roles and therapeutic implications. Transl Neurodegener 2021; 10:49. [PMID: 34876226 PMCID: PMC8650380 DOI: 10.1186/s40035-021-00273-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/09/2021] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease (AD) is the most serious age-related neurodegenerative disease and causes destructive and irreversible cognitive decline. Failures in the development of therapeutics targeting amyloid-β (Aβ) and tau, principal proteins inducing pathology in AD, suggest a paradigm shift towards the development of new therapeutic targets. The gram-negative bacteria and lipopolysaccharides (LPS) are attractive new targets for AD treatment. Surprisingly, an altered distribution of gram-negative bacteria and their LPS has been reported in AD patients. Moreover, gram-negative bacteria and their LPS have been shown to affect a variety of AD-related pathologies, such as Aβ homeostasis, tau pathology, neuroinflammation, and neurodegeneration. Moreover, therapeutic approaches targeting gram-negative bacteria or gram-negative bacterial molecules have significantly alleviated AD-related pathology and cognitive dysfunction. Despite multiple evidence showing that the gram-negative bacteria and their LPS play a crucial role in AD pathogenesis, the pathogenic mechanisms of gram-negative bacteria and their LPS have not been clarified. Here, we summarize the roles and pathomechanisms of gram-negative bacteria and LPS in AD. Furthermore, we discuss the possibility of using gram-negative bacteria and gram-negative bacterial molecules as novel therapeutic targets and new pathological characteristics for AD.
Collapse
Affiliation(s)
- Hyeon Soo Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, 35365, Republic of Korea
| | - Sujin Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, 35365, Republic of Korea
- Research Institute for Dementia Science, Konyang University, Daejeon, 35365, Republic of Korea
| | - Soo Jung Shin
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, 35365, Republic of Korea
| | - Yong Ho Park
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, 35365, Republic of Korea
| | - Yunkwon Nam
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, 35365, Republic of Korea
| | - Chae Won Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, 35365, Republic of Korea
| | - Kang Won Lee
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, 35365, Republic of Korea
| | - Sung-Min Kim
- Dandi Bioscience Inc, 6th Floor of Real Company Building, 66, Achasan-ro, Sungdong-gu, Seoul, Republic of Korea
| | - In Duk Jung
- Dandi Bioscience Inc, 6th Floor of Real Company Building, 66, Achasan-ro, Sungdong-gu, Seoul, Republic of Korea
| | - Hyun Duk Yang
- Harvard Neurology Clinic, 294 Gwanggyojungang-ro, Suji-gu, Yongin, 16943, Republic of Korea.
| | - Yeong-Min Park
- Dandi Bioscience Inc, 6th Floor of Real Company Building, 66, Achasan-ro, Sungdong-gu, Seoul, Republic of Korea.
- Department of Immunology, School of Medicine, Konkuk University, 268, Chungwondaero, Chungju-si, Chungcheongbuk-do, Republic of Korea.
| | - Minho Moon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, 35365, Republic of Korea.
- Research Institute for Dementia Science, Konyang University, Daejeon, 35365, Republic of Korea.
| |
Collapse
|
10
|
Yang J, Wise L, Fukuchi KI. TLR4 Cross-Talk With NLRP3 Inflammasome and Complement Signaling Pathways in Alzheimer's Disease. Front Immunol 2020; 11:724. [PMID: 32391019 PMCID: PMC7190872 DOI: 10.3389/fimmu.2020.00724] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/30/2020] [Indexed: 01/02/2023] Open
Abstract
Amyloid plaques, mainly composed of abnormally aggregated amyloid β-protein (Aβ) in the brain parenchyma, and neurofibrillary tangles (NFTs), consisting of hyperphosphorylated tau protein aggregates in neurons, are two pathological hallmarks of Alzheimer's disease (AD). Aβ fibrils and tau aggregates in the brain are closely associated with neuroinflammation and synapse loss, characterized by activated microglia and dystrophic neurites. Genome-wide genetic association studies revealed important roles of innate immune cells in the pathogenesis of late-onset AD by recognizing a dozen genetic risk loci that modulate innate immune activities. Furthermore, microglia, brain resident innate immune cells, have been increasingly recognized to play key, opposing roles in AD pathogenesis by either eliminating toxic Aβ aggregates and enhancing neuronal plasticity or producing proinflammatory cytokines, reactive oxygen species, and synaptotoxicity. Aggregated Aβ binds to toll-like receptor 4 (TLR4) and activates microglia, resulting in increased phagocytosis and cytokine production. Complement components are associated with amyloid plaques and NFTs. Aggregated Aβ can activate complement, leading to synapse pruning and loss by microglial phagocytosis. Systemic inflammation can activate microglial TLR4, NLRP3 inflammasome, and complement in the brain, leading to neuroinflammation, Aβ accumulation, synapse loss and neurodegeneration. The host immune response has been shown to function through complex crosstalk between the TLR, complement and inflammasome signaling pathways. Accordingly, targeting the molecular mechanisms underlying the TLR-complement-NLRP3 inflammasome signaling pathways can be a preventive and therapeutic approach for AD.
Collapse
Affiliation(s)
- Junling Yang
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, United States
| | - Leslie Wise
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, United States
| | - Ken-Ichiro Fukuchi
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, United States
| |
Collapse
|
11
|
LeBlang CJ, Medalla M, Nicoletti NW, Hays EC, Zhao J, Shattuck J, Cruz AL, Wolozin B, Luebke JI. Reduction of the RNA Binding Protein TIA1 Exacerbates Neuroinflammation in Tauopathy. Front Neurosci 2020; 14:285. [PMID: 32327969 PMCID: PMC7161592 DOI: 10.3389/fnins.2020.00285] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/12/2020] [Indexed: 12/13/2022] Open
Abstract
Neuroinflammatory processes play an integral role in the exacerbation and progression of pathology in tauopathies, a class of neurodegenerative disease characterized by aggregation of hyperphosphorylated tau protein. The RNA binding protein (RBP) T-cell Intracellular Antigen 1 (TIA1) is an important regulator of the innate immune response in the periphery, dampening cytotoxic inflammation and apoptosis during cellular stress, however, its role in neuroinflammation is unknown. We have recently shown that TIA1 regulates tau pathophysiology and toxicity in part through the binding of phospho-tau oligomers into pathological stress granules, and that haploinsufficiency of TIA1 in the P301S mouse model of tauopathy results in reduced accumulation of toxic tau oligomers, pathologic stress granules, and the development of downstream pathological features of tauopathy. The putative role of TIA1 as a regulator of the peripheral immune response led us to investigate the effects of TIA1 on neuroinflammation in the context of tauopathy, a chronic stressor in the neural environment. Here, we evaluated indicators of neuroinflammation including; reactive microgliosis and phagocytosis, pro-inflammatory cytokine release, and oxidative stress in hippocampal neurons and glia of wildtype and P301S transgenic mice expressing TIA1+/+, TIA1+/-, and TIA1-/- in both early (5 month) and advanced (9 month) disease states through biochemical, ultrastructural, and histological analyses. Our data show that both TIA1 haploinsufficiency and TIA1 knockout exacerbate neuroinflammatory processes in advanced stages of tauopathy, suggesting that TIA1 dampens the immune response in the central nervous system during chronic stress.
Collapse
Affiliation(s)
- Chelsey Jenna LeBlang
- Laboratory of Cellular Neuroscience, Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Maria Medalla
- Laboratory of Cellular Neuroscience, Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Nicholas William Nicoletti
- Laboratory of Cellular Neuroscience, Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Emma Catherine Hays
- Laboratory of Cellular Neuroscience, Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - James Zhao
- Laboratory of Cellular Neuroscience, Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Jenifer Shattuck
- Laboratory of Neurodegeneration, Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
| | - Anna Lourdes Cruz
- Laboratory of Neurodegeneration, Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
| | - Benjamin Wolozin
- Laboratory of Neurodegeneration, Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Department of Neurology, Boston University School of Medicine, Boston, MA, United States
- Department of Neuroscience, Boston University, Boston, MA, United States
| | - Jennifer Irene Luebke
- Laboratory of Cellular Neuroscience, Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
| |
Collapse
|
12
|
Torvell M, Hampton DW, Connick P, MacLullich AMJ, Cunningham C, Chandran S. A single systemic inflammatory insult causes acute motor deficits and accelerates disease progression in a mouse model of human tauopathy. ALZHEIMERS & DEMENTIA-TRANSLATIONAL RESEARCH & CLINICAL INTERVENTIONS 2019; 5:579-591. [PMID: 31650014 PMCID: PMC6804509 DOI: 10.1016/j.trci.2019.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Introduction Neuroinflammation, which contributes to neurodegeneration, is a consistent hallmark of dementia. Emerging evidence suggests that systemic inflammation also contributes to disease progression. Methods The ability of systemically administered lipopolysaccharide (LPS - 500 μg/kg) to effect acute and chronic behavioural changes in C57BL/6 and P301S tauopathy mice was assessed. Markers of pathology were assessed in the brain and spinal cord. Results P301S mice display regional microgliosis. Systemic LPS treatment induced exaggerated acute sickness behaviour and motor dysfunction in P301S mice compared with wild-type controls and advanced the onset and accelerated chronic decline. LPS treatment was associated with increased tau pathology 24 hours after LPS injection and spinal cord microgliosis at the end stage. Discussion This is the first demonstration that a single systemic inflammatory episode causes exaggerated acute functional impairments and accelerates the long-term trajectory of functional decline associated with neurodegeneration in a mouse model of human tauopathy. The findings have relevance to management of human dementias. P301S microgliosis is regional; activation occurs in the spinal cord but not in the cortex. Systemic LPS injection caused acute neurological deficits in P301S mice. This was associated with increased tau pathology 24 hours after LPS injection. This was independent of microglial priming as measured by IL-1β hyperexpression. LPS injection advanced the onset of chronic decline in P301S mice.
Collapse
Affiliation(s)
- Megan Torvell
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute at University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute at University of Cardiff, Cardiff, UK
| | - David W Hampton
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, UK
| | - Peter Connick
- The Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, Midlothian, UK
| | - Alasdair M J MacLullich
- Edinburgh Delirium Research Group, Geriatric Medicine, University of Edinburgh, Edinburgh, UK
| | - Colm Cunningham
- Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Siddharthan Chandran
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute at University of Edinburgh, Edinburgh, UK.,The Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, Midlothian, UK
| |
Collapse
|
13
|
Vogels T, Murgoci AN, Hromádka T. Intersection of pathological tau and microglia at the synapse. Acta Neuropathol Commun 2019; 7:109. [PMID: 31277708 PMCID: PMC6612163 DOI: 10.1186/s40478-019-0754-y] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/19/2019] [Indexed: 02/07/2023] Open
Abstract
Tauopathies are a heterogenous class of diseases characterized by cellular accumulation of aggregated tau and include diseases such as Alzheimer’s disease (AD), progressive supranuclear palsy and chronic traumatic encephalopathy. Tau pathology is strongly linked to neurodegeneration and clinical symptoms in tauopathy patients. Furthermore, synapse loss is an early pathological event in tauopathies and is the strongest correlate of cognitive decline. Tau pathology is additionally associated with chronic neuroinflammatory processes, such as reactive microglia, astrocytes, and increased levels of pro-inflammatory molecules (e.g. complement proteins, cytokines). Recent studies show that as the principal immune cells of the brain, microglia play a particularly important role in the initiation and progression of tau pathology and associated neurodegeneration. Furthermore, AD risk genes such as Triggering receptor expressed on myeloid cells 2 (TREM2) and Apolipoprotein E (APOE) are enriched in the innate immune system and modulate the neuroinflammatory response of microglia to tau pathology. Microglia can play an active role in synaptic dysfunction by abnormally phagocytosing synaptic compartments of neurons with tau pathology. Furthermore, microglia are involved in synaptic spreading of tau – a process which is thought to underlie the progressive nature of tau pathology propagation through the brain. Spreading of pathological tau is also the predominant target for tau-based immunotherapy. Active tau vaccines, therapeutic tau antibodies and other approaches targeting the immune system are actively explored as treatment options for AD and other tauopathies. This review describes the role of microglia in the pathobiology of tauopathies and the mechanism of action of potential therapeutics targeting the immune system in tauopathies.
Collapse
|
14
|
Lipopolysaccharide-Induced Neuroinflammation as a Bridge to Understand Neurodegeneration. Int J Mol Sci 2019; 20:ijms20092293. [PMID: 31075861 PMCID: PMC6539529 DOI: 10.3390/ijms20092293] [Citation(s) in RCA: 286] [Impact Index Per Article: 57.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/03/2019] [Accepted: 05/05/2019] [Indexed: 12/19/2022] Open
Abstract
A large body of experimental evidence suggests that neuroinflammation is a key pathological event triggering and perpetuating the neurodegenerative process associated with many neurological diseases. Therefore, different stimuli, such as lipopolysaccharide (LPS), are used to model neuroinflammation associated with neurodegeneration. By acting at its receptors, LPS activates various intracellular molecules, which alter the expression of a plethora of inflammatory mediators. These factors, in turn, initiate or contribute to the development of neurodegenerative processes. Therefore, LPS is an important tool for the study of neuroinflammation associated with neurodegenerative diseases. However, the serotype, route of administration, and number of injections of this toxin induce varied pathological responses. Thus, here, we review the use of LPS in various models of neurodegeneration as well as discuss the neuroinflammatory mechanisms induced by this toxin that could underpin the pathological events linked to the neurodegenerative process.
Collapse
|
15
|
Gratuze M, Leyns CEG, Holtzman DM. New insights into the role of TREM2 in Alzheimer's disease. Mol Neurodegener 2018; 13:66. [PMID: 30572908 PMCID: PMC6302500 DOI: 10.1186/s13024-018-0298-9] [Citation(s) in RCA: 280] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 11/28/2018] [Indexed: 12/22/2022] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia. The two histopathological markers of AD are amyloid plaques composed of the amyloid-β (Aβ) peptide, and neurofibrillary tangles of aggregated, abnormally hyperphosphorylated tau protein. The majority of AD cases are late-onset, after the age of 65, where a clear cause is still unknown. However, there are likely different multifactorial contributors including age, enviornment, biology and genetics which can increase risk for the disease. Genetic predisposition is considerable, with heritability estimates of 60-80%. Genetic factors such as rare variants of TREM2 (triggering receptor expressed on myeloid cells-2) strongly increase the risk of developing AD, confirming the role of microglia in AD pathogenesis. In the last 5 years, several studies have dissected the mechanisms by which TREM2, as well as its rare variants affect amyloid and tau pathologies and their consequences in both animal models and in human studies. In this review, we summarize increases in our understanding of the involvement of TREM2 and microglia in AD development that may open new therapeutic strategies targeting the immune system to influence AD pathogenesis.
Collapse
Affiliation(s)
- Maud Gratuze
- Department of Neurology, St. Louis, USA
- Hope Center for Neurological Disorders, St. Louis, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Cheryl E. G. Leyns
- Department of Neurology, St. Louis, USA
- Hope Center for Neurological Disorders, St. Louis, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - David M. Holtzman
- Department of Neurology, St. Louis, USA
- Hope Center for Neurological Disorders, St. Louis, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110 USA
| |
Collapse
|
16
|
Llorens-Martín M. Exercising New Neurons to Vanquish Alzheimer Disease. Brain Plast 2018; 4:111-126. [PMID: 30564550 PMCID: PMC6296267 DOI: 10.3233/bpl-180065] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2018] [Indexed: 02/07/2023] Open
Abstract
Alzheimer disease (AD) is the most common type of dementia in individuals over 65 years of age. The neuropathological hallmarks of the condition are Tau neurofibrillary tangles and Amyloid-β senile plaques. Moreover, certain susceptible regions of the brain experience a generalized lack of neural plasticity and marked synaptic alterations during the progression of this as yet incurable disease. One of these regions, the hippocampus, is characterized by the continuous addition of new neurons throughout life. This phenomenon, named adult hippocampal neurogenesis (AHN), provides a potentially endless source of new synaptic elements that increase the complexity and plasticity of the hippocampal circuitry. Numerous lines of evidence show that physical activity and environmental enrichment (EE) are among the most potent positive regulators of AHN. Given that neural plasticity is markedly decreased in many neurodegenerative diseases, the therapeutic potential of making certain lifestyle changes, such as increasing physical activity, is being recognised in several non-pharmacologic strategies seeking to slow down or prevent the progression of these diseases. This review article summarizes current evidence supporting the putative therapeutic potential of EE and physical exercise to increase AHN and hippocampal plasticity both under physiological and pathological circumstances, with a special emphasis on neurodegenerative diseases and AD.
Collapse
Affiliation(s)
- María Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSIC-UAM, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases CIBERNED, Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| |
Collapse
|
17
|
Newcombe EA, Camats-Perna J, Silva ML, Valmas N, Huat TJ, Medeiros R. Inflammation: the link between comorbidities, genetics, and Alzheimer's disease. J Neuroinflammation 2018; 15:276. [PMID: 30249283 PMCID: PMC6154824 DOI: 10.1186/s12974-018-1313-3] [Citation(s) in RCA: 333] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/11/2018] [Indexed: 12/21/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder, most cases of which lack a clear causative event. This has made the disease difficult to characterize and, thus, diagnose. Although some cases are genetically linked, there are many diseases and lifestyle factors that can lead to an increased risk of developing AD, including traumatic brain injury, diabetes, hypertension, obesity, and other metabolic syndromes, in addition to aging. Identifying common factors and trends between these conditions could enhance our understanding of AD and lead to the development of more effective treatments. Although the immune system is one of the body’s key defense mechanisms, chronic inflammation has been increasingly linked with several age-related diseases. Moreover, it is now well accepted that chronic inflammation has an important role in the onset and progression of AD. In this review, the different inflammatory signals associated with AD and its risk factors will be outlined to demonstrate how chronic inflammation may be influencing individual susceptibility to AD. Our goal is to bring attention to potential shared signals presented by the immune system during different conditions that could lead to the development of successful treatments.
Collapse
Affiliation(s)
- Estella A Newcombe
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia.
| | - Judith Camats-Perna
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia
| | - Mallone L Silva
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia
| | - Nicholas Valmas
- Queensland Brain Institute, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Tee Jong Huat
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia.,Centre for Stem Cell Ageing and Regenerative Engineering, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Rodrigo Medeiros
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia.
| |
Collapse
|
18
|
Kokiko-Cochran ON, Godbout JP. The Inflammatory Continuum of Traumatic Brain Injury and Alzheimer's Disease. Front Immunol 2018; 9:672. [PMID: 29686672 PMCID: PMC5900037 DOI: 10.3389/fimmu.2018.00672] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 03/19/2018] [Indexed: 12/23/2022] Open
Abstract
The post-injury inflammatory response is a key mediator in long-term recovery from traumatic brain injury (TBI). Moreover, the immune response to TBI, mediated by microglia and macrophages, is influenced by existing brain pathology and by secondary immune challenges. For example, recent evidence shows that the presence of beta-amyloid and phosphorylated tau protein, two hallmark features of AD that increase during normal aging, substantially alter the macrophage response to TBI. Additional data demonstrate that post-injury microglia are “primed” and become hyper-reactive following a subsequent acute immune challenge thereby worsening recovery. These alterations may increase the incidence of neuropsychiatric complications after TBI and may also increase the frequency of neurodegenerative pathology. Therefore, the purpose of this review is to summarize experimental studies examining the relationship between TBI and development of AD-like pathology with an emphasis on the acute and chronic microglial and macrophage response following injury. Furthermore, studies will be highlighted that examine the degree to which beta-amyloid and tau accumulation as well as pre- and post-injury immune stressors influence outcome after TBI. Collectively, the studies described in this review suggest that the brain’s immune response to injury is a key mediator in recovery, and if compromised by previous, coincident, or subsequent immune stressors, post-injury pathology and behavioral recovery will be altered.
Collapse
Affiliation(s)
- Olga N Kokiko-Cochran
- Department of Neuroscience, Institute for Behavioral Medicine Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Jonathan P Godbout
- Department of Neuroscience, Institute for Behavioral Medicine Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| |
Collapse
|
19
|
Gai Z, Su D, Wang Y, Li W, Cui B, Li K, She X, Wang R. Effects of chronic noise on the corticotropin-releasing factor system in the rat hippocampus: relevance to Alzheimer's disease-like tau hyperphosphorylation. Environ Health Prev Med 2017; 22:79. [PMID: 29228900 PMCID: PMC5725896 DOI: 10.1186/s12199-017-0686-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 11/30/2017] [Indexed: 11/30/2022] Open
Abstract
Background Chronic noise exposure has been associated with tau hyperphosphorylation and Alzheimer’s disease (AD)-like pathological changes, but the underlying mechanism is unknown. In this study, we explored the effects of long-term noise exposure on the corticotropin-releasing factor (CRF) system in the hippocampus and its role in noise-induced tau phosphorylation. Methods Sixty-four rats were randomly divided into the noise-exposed group and the control group, and rats in the exposure group were exposed to 95 dB SPL white noise for 30 consecutive days. The levels of CRF, CRFR1, CRFR2, and total tau and phosphorylated tau (p-tau) at Ser396 (S396) and Thr205 (T205) in the hippocampus were measured at different time points after the final noise exposure. The co-localized distribution of CRF and p-tau (T205) in the hippocampus was evaluated using double-labeling immunofluorescence. Results Long-term exposure to noise for 30 consecutive days significantly increased the expression of CRF and CRFR1 and their mRNAs levels in the hippocampus, which persisted for 7 days after final exposure. In contrast, CRFR2 was raised for 3–7 days following the last exposure. These alterations were also concomitant with the phosphorylation of tau at S396 and T205. Furthermore, there was co-localization of p-tau and CRF in hippocampal neurons. Conclusion Chronic noise leads to long-lasting increases in the hippocampal CRF system and the hyperphosphorylation of tau in the hippocampus. Our results also provide evidence for the involvement of the CRF system in noise-induced AD-like neurodegeneration.
Collapse
Affiliation(s)
- Zhihui Gai
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, 300050, China.,Shengli Oil Field Central Hospital, Dongying, 257034, China.,Shandong Academy of Occupational Health and Occupational Medicine, 18877, Jingshi Road, Lixia District, Jinan, 250062, China
| | - Donghong Su
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, 300050, China.,Shengli Oil Field Central Hospital, Dongying, 257034, China.,Shandong Academy of Occupational Health and Occupational Medicine, 18877, Jingshi Road, Lixia District, Jinan, 250062, China
| | - Yawen Wang
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, 300050, China
| | - Wenlong Li
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, 300050, China.,School of Public Health and Management, Weifang Medical University, Weifang, China
| | - Bo Cui
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, 300050, China. .,Department of Occupational Hygiene, Institute of Health and Environmental Medicine, Academy of Military Medical Sciences, 1, Dali Road, Heping District, Tianjin, 300050, China.
| | - Kang Li
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, 300050, China
| | - Xiaojun She
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, 300050, China
| | - Rui Wang
- Shandong Academy of Occupational Health and Occupational Medicine, 18877, Jingshi Road, Lixia District, Jinan, 250062, China.
| |
Collapse
|
20
|
Kulbe JR, Hall ED. Chronic traumatic encephalopathy-integration of canonical traumatic brain injury secondary injury mechanisms with tau pathology. Prog Neurobiol 2017; 158:15-44. [PMID: 28851546 PMCID: PMC5671903 DOI: 10.1016/j.pneurobio.2017.08.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 08/09/2017] [Accepted: 08/17/2017] [Indexed: 12/14/2022]
Abstract
In recent years, a new neurodegenerative tauopathy labeled Chronic Traumatic Encephalopathy (CTE), has been identified that is believed to be primarily a sequela of repeated mild traumatic brain injury (TBI), often referred to as concussion, that occurs in athletes participating in contact sports (e.g. boxing, American football, Australian football, rugby, soccer, ice hockey) or in military combatants, especially after blast-induced injuries. Since the identification of CTE, and its neuropathological finding of deposits of hyperphosphorylated tau protein, mechanistic attention has been on lumping the disorder together with various other non-traumatic neurodegenerative tauopathies. Indeed, brains from suspected CTE cases that have come to autopsy have been confirmed to have deposits of hyperphosphorylated tau in locations that make its anatomical distribution distinct for other tauopathies. The fact that these individuals experienced repetitive TBI episodes during their athletic or military careers suggests that the secondary injury mechanisms that have been extensively characterized in acute TBI preclinical models, and in TBI patients, including glutamate excitotoxicity, intracellular calcium overload, mitochondrial dysfunction, free radical-induced oxidative damage and neuroinflammation, may contribute to the brain damage associated with CTE. Thus, the current review begins with an in depth analysis of what is known about the tau protein and its functions and dysfunctions followed by a discussion of the major TBI secondary injury mechanisms, and how the latter have been shown to contribute to tau pathology. The value of this review is that it might lead to improved neuroprotective strategies for either prophylactically attenuating the development of CTE or slowing its progression.
Collapse
Affiliation(s)
- Jacqueline R Kulbe
- Spinal Cord & Brain Injury Research Center, University of Kentucky College of Medicine, United States; Department of Neuroscience, University of Kentucky College of Medicine, United States
| | - Edward D Hall
- Spinal Cord & Brain Injury Research Center, University of Kentucky College of Medicine, United States; Department of Neuroscience, University of Kentucky College of Medicine, United States.
| |
Collapse
|
21
|
Obst J, Simon E, Mancuso R, Gomez-Nicola D. The Role of Microglia in Prion Diseases: A Paradigm of Functional Diversity. Front Aging Neurosci 2017; 9:207. [PMID: 28690540 PMCID: PMC5481309 DOI: 10.3389/fnagi.2017.00207] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 06/09/2017] [Indexed: 12/26/2022] Open
Abstract
Inflammation is a major component of neurodegenerative diseases. Microglia are the innate immune cells in the central nervous system (CNS). In the healthy brain, microglia contribute to tissue homeostasis and regulation of synaptic plasticity. Under disease conditions, they play a key role in the development and maintenance of the neuroinflammatory response, by showing enhanced proliferation and activation. Prion diseases are progressive chronic neurodegenerative disorders associated with the accumulation of the scrapie prion protein PrPSc, a misfolded conformer of the cellular prion protein PrPC. This review article provides the current knowledge on the role of microglia in the pathogenesis of prion disease. A large body of evidence shows that microglia can trigger neurotoxic pathways contributing to progressive degeneration. Yet, microglia are also crucial for controlling inflammatory, repair and regenerative processes. This dual role of microglia is regulated by multiple pathways and evidences the ability of these cells to polarize into distinct phenotypes with characteristic functions. The awareness that the neuroinflammatory response is inextricably involved in producing tissue damage as well as repair in neurodegenerative disorders, opens new perspectives for the modulation of the immune system. A better understanding of this complex process will be essential for developing effective therapies for neurodegenerative diseases, in order to improve the quality of life of patients and mitigating the personal, economic and social consequences derived from these diseases.
Collapse
Affiliation(s)
- Juliane Obst
- Biological Sciences, University of Southampton, Southampton General HospitalSouthampton, United Kingdom
| | - Emilie Simon
- Biological Sciences, University of Southampton, Southampton General HospitalSouthampton, United Kingdom
| | - Renzo Mancuso
- Biological Sciences, University of Southampton, Southampton General HospitalSouthampton, United Kingdom
| | - Diego Gomez-Nicola
- Biological Sciences, University of Southampton, Southampton General HospitalSouthampton, United Kingdom
| |
Collapse
|
22
|
Does neuroinflammation drive the relationship between tau hyperphosphorylation and dementia development following traumatic brain injury? Brain Behav Immun 2017; 60:369-382. [PMID: 27686843 DOI: 10.1016/j.bbi.2016.09.027] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 09/06/2016] [Accepted: 09/25/2016] [Indexed: 12/14/2022] Open
Abstract
A history of traumatic brain injury (TBI) is linked to an increased risk for the later development of dementia. This encompasses a variety of neurodegenerative diseases including Alzheimer's Disease (AD) and chronic traumatic encephalopathy (CTE), with AD linked to history of moderate-severe TBI and CTE to a history of repeated concussion. Of note, both AD and CTE are characterized by the abnormal accumulation of hyperphosphorylated tau aggregates, which are thought to play an important role in the development of neurodegeneration. Hyperphosphorylation of tau leads to destabilization of microtubules, interrupting axonal transport, whilst tau aggregates are associated with synaptic dysfunction. The exact mechanisms via which TBI may promote the later tauopathy and its role in the later development of dementia are yet to be fully determined. Following TBI, it is proposed that axonal injury may provide the initial perturbation of tau, by promoting its dissociation from microtubules, facilitating its phosphorylation and aggregation. Altered tau dynamics may then be exacerbated by the chronic persistent inflammatory response that has been shown to persist for decades following the initial impact. Importantly, immune activation has been shown to play a role in accelerating disease progression in other tauopathies, with pro-inflammatory cytokines, like IL-1β, shown to activate kinases that promote tau hyperphosphorylation. Thus, targeting the inflammatory response in the sub-acute phase following TBI may represent a promising target to halt the alterations in tau dynamics that may precede overt neurodegeneration and later development of dementia.
Collapse
|
23
|
Barron M, Gartlon J, Dawson LA, Atkinson PJ, Pardon MC. A state of delirium: Deciphering the effect of inflammation on tau pathology in Alzheimer's disease. Exp Gerontol 2016; 94:103-107. [PMID: 27979768 PMCID: PMC5479936 DOI: 10.1016/j.exger.2016.12.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/01/2016] [Accepted: 12/07/2016] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease (AD), the predominant form of dementia, is highly correlated with the abnormal hyperphosphorylation and aggregation of tau. Immune responses are key drivers of AD and how they contribute to tau pathology in human disease remains largely unknown. This review summarises current knowledge on the association between inflammatory processes and tau pathology. While, preclinical evidence suggests that inflammation can indeed induce tau hyperphosphorylation at both pre- and post-tangles epitopes, a better understanding of whether this develops into advanced pathological features such as neurofibrillary tangles is needed. Microglial cells, the immune phagocytes in the central nervous system, appear to play a key role in regulating tau pathology, but the underlying mechanisms are not fully understood. Their activation can be detrimental via the secretion of pro-inflammatory mediators, particularly interleukin-1β, but also potentially beneficial through phagocytosis of extracellular toxic tau oligomers. Nevertheless, anti-inflammatory treatments in animal models were found protective, but whether or not they affect microglial phagocytosis of tau species is unknown. However, one major challenge to our understanding of the role of inflammation in the progression of tau pathology is the preclinical models used to address this question. They mostly rely on the use of septic doses of lipopolysaccharide that do not reflect the inflammatory conditions experienced AD patients, questioning whether the impact of inflammation on tau pathology in these models is dose-dependent and relevant to the human disease. The use of more translational models of inflammation corroborated with verification in clinical investigations are necessary to progress our understanding of the interplay between inflammation and tau pathology. Inflammation modulates tau function in Alzheimer's disease. LPS induces tau phosphorylation in vivo. Modulation of late stage tau pathology is less clear. Microglial shows potential to slow spread of extracellular tau. A holistic approach will determine the role of inflammation in Alzheimer's disease.
Collapse
Affiliation(s)
- Matthew Barron
- School of Life sciences, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, UK
| | - Jane Gartlon
- Eisai Inc., 4 Corporate Drive, Andover, MA 01810, USA
| | - Lee A Dawson
- Astex Pharmaceuticals, 436 Cambridge Science Park Rd, Cambridge CB4 0QA, UK
| | - Peter J Atkinson
- Eisai Ltd., EMEA Knowledge Centre, Mosquito Way, Hatfield, Hertfordshire, AL10 9SN, UK
| | - Marie-Christine Pardon
- School of Life sciences, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, UK.
| |
Collapse
|
24
|
Campbell SN, Zhang C, Roe AD, Lee N, Lao KU, Monte L, Donohue MC, Rissman RA. Impact of CRFR1 Ablation on Amyloid-β Production and Accumulation in a Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2016; 45:1175-84. [PMID: 25697705 DOI: 10.3233/jad-142844] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Stress exposure and the corticotropin-releasing factor (CRF) system have been implicated as mechanistically involved in both Alzheimer's disease (AD) and associated rodent models. In particular, the major stress receptor, CRF receptor type 1 (CRFR1), modulates cellular activity in many AD-relevant brain areas, and has been demonstrated to impact both tau phosphorylation and amyloid-β (Aβ) pathways. The overarching goal of our laboratory is to develop and characterize agents that impact the CRF signaling system as disease-modifying treatments for AD. In the present study, we developed a novel transgenic mouse to determine whether partial or complete ablation of CRFR1 was feasible in an AD transgenic model and whether this type of treatment could impact Aβ pathology. Double transgenic AD mice (PSAPP) were crossed to mice null for CRFR1; resultant CRFR1 heterozygous (PSAPP-R1(+/-)) and homozygous (PSAPP-R1(-/-)) female offspring were used at 12 months of age to examine the impact of CRFR1 disruption on the severity of AD Aβ levels and pathology. We found that both PSAPP-R1(+/-) and PSAPP-R1(-/-) had significantly reduced Aβ burden in the hippocampus, insular, rhinal, and retrosplenial cortices. Accordingly, we observed dramatic reductions in Aβ peptides and AβPP-CTFs, providing support for a direct relationship between CRFR1 and Aβ production pathways. In summary, our results suggest that interference of CRFR1 in an AD model is tolerable and is efficacious in impacting Aβ neuropathology.
Collapse
Affiliation(s)
- Shannon N Campbell
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Cheng Zhang
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Allyson D Roe
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Nickey Lee
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Kathleen U Lao
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Louise Monte
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Michael C Donohue
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA Department of Family Preventive Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| |
Collapse
|
25
|
Liu J, Wang D, Li SQ, Yu Y, Ye RD. Suppression of LPS-induced tau hyperphosphorylation by serum amyloid A. J Neuroinflammation 2016; 13:28. [PMID: 26838764 PMCID: PMC4736117 DOI: 10.1186/s12974-016-0493-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 01/24/2016] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Accumulation of hyperphosphorylated tau is a major neuropathological feature of tauopathies including Alzheimer's disease (AD). Serum amyloid A (SAA), an acute-phase protein with cytokine-like property, has been implicated in amyloid deposition. It remains unclear whether SAA affects tau hyperphosphorylation. METHODS Potential involvement of SAA in tau hyperphosphorylation was examined using intracerebral injection of SAA, and in Saa3 (-/-) mice receiving systemic administration of lipopolysaccharide (LPS). Induced SAA expression and microglial activation were evaluated in these mice using real-time PCR and/or immunofluorescence staining. Cultured primary neuronal cells were treated with condition media (CM) from SAA-stimulated primary microglial cells. The alteration in tau hyperphosphorylation was determined using Western blotting. RESULTS Saa3 is the predominant form of SAA proteins induced by LPS in the mouse brain that co-localizes with neurons. Overexpression of SAA by intracerebral injection attenuated tau hyperphosphorylation in the brain. Conversely, Saa3 deficiency enhanced tau phosphorylation induced by systemic LPS administration. Intracerebral injection of SAA also induced the activation of microglia in the brains. IL-10 released to CM from SAA-stimulated microglia attenuated tau hyperphosphorylation in cultured primary neurons. IL-10 neutralizing antibody reversed the effect of SAA in the attenuation of tau phosphorylation. CONCLUSIONS LPS-induced expression of SAA proteins in the brain leads to the activation of microglia and release of IL-10, which in turn suppresses tau hyperphosphorylation in a mouse model of systemic inflammation.
Collapse
Affiliation(s)
- Jin Liu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Ding Wang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Shu-Qin Li
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Yang Yu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Richard D Ye
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China.
- Institute of Chinese Medical Sciences, University of Macau, Macau SAR, China.
| |
Collapse
|
26
|
Czapski GA, Gąssowska M, Wilkaniec A, Chalimoniuk M, Strosznajder JB, Adamczyk A. The mechanisms regulating cyclin-dependent kinase 5 in hippocampus during systemic inflammatory response: The effect on inflammatory gene expression. Neurochem Int 2016; 93:103-12. [PMID: 26806339 DOI: 10.1016/j.neuint.2016.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 01/15/2016] [Accepted: 01/20/2016] [Indexed: 11/19/2022]
Abstract
Cyclin-dependent kinase 5 (Cdk5) is critical for nervous system's development and function, and its aberrant activation contributes to pathomechanism of Alzheimer's disease and other neurodegenerative disorders. It was recently suggested that Cdk5 may participate in regulation of inflammatory signalling. The aim of this study was to analyse the mechanisms involved in regulating Cdk5 activity in the brain during systemic inflammatory response (SIR) as well as the involvement of Cdk5 in controlling the expression of inflammatory genes. Genetic and biochemical alterations in hippocampus were analysed 3 and 12 h after intraperitoneal injection of lipopolysaccharide. We observed an increase in both Cdk5 gene expression and protein level. Moreover, phosphorylation of Cdk5 on Ser159 was significantly enhanced. Also transcription of Cdk5-regulatory protein (p35/Cdk5r1) was augmented, and the level of p25, calpain-dependent cleavage product of p35, was increased. All these results demonstrated rapid activation of Cdk5 in the brain during SIR. Hyperactivity of Cdk5 contributed to enhanced phosphorylation of tau and glycogen synthase kinase 3β. Inhibition of Cdk5 with Roscovitine reduced activation of NF-κB and expression of inflammation-related genes, demonstrating the critical role of Cdk5 in regulation of gene transcription during SIR.
Collapse
Affiliation(s)
- Grzegorz A Czapski
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland.
| | - Magdalena Gąssowska
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Anna Wilkaniec
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Małgorzata Chalimoniuk
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Joanna B Strosznajder
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Agata Adamczyk
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| |
Collapse
|
27
|
Le MH, Weissmiller AM, Monte L, Lin PH, Hexom TC, Natera O, Wu C, Rissman RA. Functional Impact of Corticotropin-Releasing Factor Exposure on Tau Phosphorylation and Axon Transport. PLoS One 2016; 11:e0147250. [PMID: 26790099 PMCID: PMC4720402 DOI: 10.1371/journal.pone.0147250] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/03/2016] [Indexed: 01/20/2023] Open
Abstract
Stress exposure or increased levels of corticotropin-releasing factor (CRF) induce hippocampal tau phosphorylation (tau-P) in rodent models, a process that is dependent on the type-1 CRF receptor (CRFR1). Although these preclinical studies on stress-induced tau-P provide mechanistic insight for epidemiological work that identifies stress as a risk factor for Alzheimer’s disease (AD), the actual impact of stress-induced tau-P on neuronal function remains unclear. To determine the functional consequences of stress-induced tau-P, we developed a novel mouse neuronal cell culture system to explore the impact of acute (0.5hr) and chronic (2hr) CRF treatment on tau-P and integral cell processes such as axon transport. Consistent with in vivo reports, we found that chronic CRF treatment increased tau-P levels and caused globular accumulations of phosphorylated tau in dendritic and axonal processes. Furthermore, while both acute and chronic CRF treatment led to significant reduction in CREB activation and axon transport of brain-derived neurotrophic factor (BDNF), this was not the case with mitochondrial transport. Acute CRF treatment caused increased mitochondrial velocity and distance traveled in neurons, while chronic CRF treatment modestly decreased mitochondrial velocity and greatly increased distance traveled. These results suggest that transport of cellular energetics may take priority over growth factors during stress. Tau-P was required for these changes, as co-treatment of CRF with a GSK kinase inhibitor prevented CRF-induced tau-P and all axon transport changes. Collectively, our results provide mechanistic insight into the consequences of stress peptide-induced tau-P and provide an explanation for how chronic stress via CRF may lead to neuronal vulnerability in AD.
Collapse
Affiliation(s)
- Michelle H. Le
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - April M. Weissmiller
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Louise Monte
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Po Han Lin
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Tia C. Hexom
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Orlangie Natera
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Robert A. Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
- Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, United States of America
- * E-mail:
| |
Collapse
|
28
|
Steinmetz D, Ramos E, Campbell SN, Morales T, Rissman RA. Reproductive Stage and Modulation of Stress-Induced Tau Phosphorylation in Female Rats. J Neuroendocrinol 2015; 27:827-34. [PMID: 26510116 PMCID: PMC4625411 DOI: 10.1111/jne.12323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 08/24/2015] [Accepted: 09/02/2015] [Indexed: 01/08/2023]
Abstract
Chronic stress is implicated as a risk factor for Alzheimer's disease (AD) and other neurodegenerative disorders. Although the specific mechanisms linking stress exposure and AD vulnerability have yet to be fully determined, our laboratory and others have shown that acute and repeated restraint stress in rodents leads to an increase in hippocampal tau phosphorylation (tau-P) and tau insolubility, a critical component of tau pathology in AD. Although tau phosphorylation induced by acute psychological stress is dependent on intact signaling through the type 1 corticotropin-releasing factor receptor, how sex steroids or other modulators contribute to this effect is unknown. A naturally occurring attenuation of the stress response is observed in female rats at the end of pregnancy and throughout lactation. To test the hypothesis that decreased sensitivity to stress during lactation modulates stress-induced tau-P, cohorts of virgin, lactating and weaned female rats were subjected to 30 min of restraint stress or no stress (control) and were killed 20 min or 24 h after the episode. Exposure to restraint stress induced a significant decrease in tau-P in the hippocampus of lactating rats killed 20 min after stress compared to lactating controls and virgins subjected to stress treatment. Lactating rats killed 24 hr after restraint stress exposure showed significant elevation in tau-P compared to lactating cohorts killed 20 min after stress. Levels of tau-P in these latter cohorts did not differ signficantly from control animals. Furthermore, glycogen synthase kinase (GSK)3-α levels were significantly decreased in stressed lactating animals at both timepoints. This suggests a steep, yet transient stress-induced dephosphorylation of tau, influenced by GSK3, in the hippocampus of lactating rats.
Collapse
Affiliation(s)
- Danielle Steinmetz
- Department of Neurosciences, University of California, San Diego School of Medicine, Queretaro, Mexico
| | - Eugenia Ramos
- Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Queretaro, Mexico
| | - Shannon N. Campbell
- Department of Neurosciences, University of California, San Diego School of Medicine, Queretaro, Mexico
| | - Teresa Morales
- Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Queretaro, Mexico
| | - Robert A. Rissman
- Department of Neurosciences, University of California, San Diego School of Medicine, Queretaro, Mexico
- Correspondence to: Robert A. Rissman, Ph.D., Department of Neurosciences, UCSD School of Medicine, 9500 Gilman Drive, MTF 314 M/C 0624, La Jolla, CA 92093-0624; Tel: 858-246-0140; Fax: 858-246-0139;
| |
Collapse
|
29
|
Campbell SN, Zhang C, Monte L, Roe AD, Rice KC, Taché Y, Masliah E, Rissman RA. Increased tau phosphorylation and aggregation in the hippocampus of mice overexpressing corticotropin-releasing factor. J Alzheimers Dis 2015; 43:967-76. [PMID: 25125464 DOI: 10.3233/jad-141281] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Clinical and basic science research suggests that stress and/or changes in central stress signaling intermediates may be involved in Alzheimer's disease (AD) pathogenesis. Although the links between stress and AD remain unsettled, data from our group and others have established that stress exposure in rodents may confer susceptibility to AD pathology by inducing hippocampal tau phosphorylation (tau-P). Work in our laboratory has shown that stress-induced tau-P requires activation of the type-1 corticotropin-releasing factor receptor (CRFR1). CRF overexpressing (CRF-OE) mice are a model of chronic stress that display cognitive impairment at 9-10 month of age. In this study we used 6-7 month old CRF-OE mice to examine whether sustained exposure to CRF and stress steroids would impact hippocampal tau-P and kinase activity in the presence or absence of the CRFR1-specific antagonist, R121919, given daily for 30 days. CRF-OE mice had significantly elevated tau-P compared to wild type (WT) mice at the AT8 (S202/T204), PHF-1 (S396/404), S262, and S422 sites. Treating CRF-OE mice with R121919 blocked phosphorylation at the AT8 (S202/T204) and PHF-1 (S396/404) sites, but not at the S262 and S422 sites and reduced phosphorylation of c-Jun N Terminal Kinase (JNK). Examination of hippocampal extracts from CRF-OE mice at the ultrastructural level revealed negatively stained round/globular aggregates that were positively labeled by PHF-1. These data suggest critical roles for CRF and CRFR1 in tau-P and aggregation and may have implications for the development of AD cognitive decline.
Collapse
Affiliation(s)
- Shannon N Campbell
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Cheng Zhang
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Louise Monte
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Allyson D Roe
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Kenner C Rice
- Chemical Biology Research Branch, National Institutes on Drug Abuse and Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Yvette Taché
- Center for Neurobiology of Stress and Women's Health, Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA CURE Digestive Diseases Research Center and Center for Neurobiology of Stress, Digestive Diseases Division at the University of California Los Angeles, and VA Greater Los Angeles Health Care System Los Angeles, CA, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA Department of Pathology, University of California, San Diego, La Jolla, CA, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| |
Collapse
|
30
|
Gasparotto J, Senger MR, Kunzler A, Degrossoli A, de Simone SG, Bortolin RC, Somensi N, Girardi CS, de Souza CDSF, Calabrese KDS, Dal-Pizzol F, Moreira JCF, Silva FP, Gelain DP. Increased tau phosphorylation and receptor for advanced glycation endproducts (RAGE) in the brain of mice infected with Leishmania amazonensis. Brain Behav Immun 2015; 43:37-45. [PMID: 25014011 DOI: 10.1016/j.bbi.2014.06.204] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/20/2014] [Accepted: 06/30/2014] [Indexed: 12/17/2022] Open
Abstract
Leishmaniasis is a parasitosis caused by several species of the genus Leishmania, an obligate intramacrophagic parasite. Although neurologic symptoms have been observed in human cases of leishmaniasis, the manifestation of neurodegenerative processes is poorly studied. The aim of the present work was to investigate if peripheral infection of BALB/c mice with Leishmania amazonensis affects tau phosphorylation and RAGE protein content in the brain, which represent biochemical markers of neurodegenerative processes observed in diseases with a pro-inflammatory component, including Alzheimer's disease and Down syndrome. Four months after a single right hind footpad subcutaneous injection of L. amazonensis, the brain cortex of BALB/c mice was isolated. Western blot analysis indicated an increase in tau phosphorylation (Ser(396)) and RAGE immunocontent in infected animals. Brain tissue TNF-α, IL-1β, and IL-6 levels were not different from control animals; however, increased protein carbonylation, decreased IFN-γ levels and impairment in antioxidant defenses were detected. Systemic antioxidant treatment (NAC 20mg/kg, i.p.) inhibited tau phosphorylation and recovered IFN-γ levels. These data, altogether, indicate an association between impaired redox state, tau phosphorylation and RAGE up-regulation in the brain cortex of animals infected with L. amazonensis. In this context, it is possible that neurologic symptoms associated to chronic leishmaniasis are associated to disruptions in the homeostasis of CNS proteins, such as tau and RAGE, as consequence of oxidative stress. This is the first demonstration of alterations in biochemical parameters of neurodegeneration in an experimental model of Leishmania infection.
Collapse
Affiliation(s)
- Juciano Gasparotto
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Mario Roberto Senger
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica de Proteínas e Peptídeos, 21040-360 Rio de Janeiro, RJ, Brazil
| | - Alice Kunzler
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Adriana Degrossoli
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica de Proteínas e Peptídeos, 21040-360 Rio de Janeiro, RJ, Brazil
| | - Salvatore Giovanni de Simone
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica de Proteínas e Peptídeos, 21040-360 Rio de Janeiro, RJ, Brazil
| | - Rafael Calixto Bortolin
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Nauana Somensi
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Carolina Saibro Girardi
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Celeste da Silva Freitas de Souza
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica de Proteínas e Peptídeos, 21040-360 Rio de Janeiro, RJ, Brazil
| | - Kátia da Silva Calabrese
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica de Proteínas e Peptídeos, 21040-360 Rio de Janeiro, RJ, Brazil
| | - Felipe Dal-Pizzol
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil
| | - José Claudio Fonseca Moreira
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Floriano Paes Silva
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica de Proteínas e Peptídeos, 21040-360 Rio de Janeiro, RJ, Brazil
| | - Daniel Pens Gelain
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
| |
Collapse
|
31
|
Choi MS, Kwak HJ, Kweon KJ, Hwang JM, Shin JW, Sohn NW. Effects of β-Asarone on Pro-Inflammatory Cytokines and Learning and Memory Impairment in Lipopolysaccharide-Treated Mice. ACTA ACUST UNITED AC 2013. [DOI: 10.6116/kjh.2013.28.6.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
32
|
Luo X, Yang L, Chen X, Li S. Tau hyperphosphorylation: a downstream effector of isoflurane-induced neuroinflammation in aged rodents. Med Hypotheses 2013; 82:94-6. [PMID: 24290657 DOI: 10.1016/j.mehy.2013.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 11/10/2013] [Accepted: 11/14/2013] [Indexed: 11/15/2022]
Abstract
Postoperative cognitive dysfunction (POCD) is a severe neurological sequela after anesthesia and surgery. Multiple risk factors, such as advanced age and anesthesia duration, relevant to POCD have been made out, although the pathophysiological mechanisms of this complication need to be further elucidated. To date, there is a substantial body of evidence implicating that neuroinflammatory cytokines and the subsequent neuroinflammatory response contribute to the cognitive impairment in aged rodents exposed to isoflurane, a commonly used general anesthetic. Interestingly, this cognitive disorder is mitigated by anti-inflammatory agents even 14 days after isoflurane exposure. In addition, isoflurane-induced upregulation of neuroinflammatory cytokines is only limited within 48 h. So a first possibility to consider is a downstream effector of isoflurane-induced neuroinflammatory cytokines which contributes to the long-lasting cognitive dysfunction. In Alzheimer's disease (AD) models, proinflammatory cytokines can induce tau hyperphosphorylation which is associated with synaptic abnormality and further cognitive impairment. It is unknown whether isoflurane-induced neuroinflammatory cytokines can trigger tau hyperphosphorylation. Taken together, we hypothesize that tau hyperphosphorylation is a downstream target of isoflurane-induced neuroinflammatory response and thus bridges the isoflurane-induced relatively transient neuroinflammatory process to the long-term cognitive impairment.
Collapse
Affiliation(s)
- Xiaoxiao Luo
- Grade 2010, The Second Clinical College, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei 430030, China
| | - Liu Yang
- Department of Anesthesiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, 1095 JieFang Avenue, Wuhan, Hubei 430030, China
| | - Xin Chen
- Department of Anesthesiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, 1095 JieFang Avenue, Wuhan, Hubei 430030, China
| | - Shiyong Li
- Department of Anesthesiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, 1095 JieFang Avenue, Wuhan, Hubei 430030, China.
| |
Collapse
|
33
|
Chronic noise exposure and Alzheimer disease: Is there an etiological association? Med Hypotheses 2013; 81:623-6. [DOI: 10.1016/j.mehy.2013.07.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/27/2013] [Accepted: 07/05/2013] [Indexed: 11/19/2022]
|
34
|
Stepanichev MY, Onufriev MV, Piskunov AK, Moiseeva YV, Lazareva NA, Moiseenok AG, Gusev PV, Gulyaeva NV. The effects of derivatives of pantothenic acid on free-radical processes and the corticosterone level in the hippocampus and neocortex of rats after interoceptive stress. NEUROCHEM J+ 2013. [DOI: 10.1134/s1819712413020062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
35
|
de Oliveira RB, Senger MR, Vasques LM, Gasparotto J, dos Santos JPA, Pasquali MADB, Moreira JCF, Silva FP, Gelain DP. Schistosoma mansoni infection causes oxidative stress and alters receptor for advanced glycation endproduct (RAGE) and tau levels in multiple organs in mice. Int J Parasitol 2013; 43:371-9. [PMID: 23369670 DOI: 10.1016/j.ijpara.2012.12.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/08/2012] [Accepted: 12/10/2012] [Indexed: 12/31/2022]
Abstract
Schistosomiasis is a parasitic disease caused by trematode worms from the Schistosoma genus and is characterized by high rates of morbidity. The main organs affected in this pathology, such as liver, kidneys and spleen, are shifted to a pro-oxidant state in the course of the infection. Here, we compared oxidative stress parameters of liver, kidney and spleen with other organs affected by schistosomiasis - heart, brain cortex and lungs. The results demonstrated that mice infected with Schistosoma mansoni had altered non-enzymatic antioxidant status in lungs and brain, increased carbonyl levels in lungs, and a moderate level of oxidative stress in heart. A severe redox imbalance in liver and kidneys and decreased non-enzymatic antioxidant capacity in spleen were also observed. Superoxide dismutase and catalase activities were differently modulated in liver, kidney and heart, and we found that differences in Superoxide dismutase 2 and catalase protein content may be responsible for these differences. Lungs had decreased receptor for advanced glycation endproduct expression and the brain cortex presented altered tau expression and phosphorylation levels, suggesting important molecular changes in these tissues, as homeostasis of these proteins is widely associated with the normal function of their respective organs. We believe that these results demonstrate for the first time that changes in the redox profile and expression of tissue-specific proteins of organs such as heart, lungs and brain are observed in early stages of S. mansoni infection.
Collapse
Affiliation(s)
- Ramatis Birnfeld de Oliveira
- Universidade Federal do Rio Grande do Sul, Departamento de Bioquímica, Centro de Estudos em Estresse Oxidativo, Porto Alegre, RS, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
The novel calpain inhibitor A-705253 prevents stress-induced tau hyperphosphorylation in vitro and in vivo. Neuropharmacology 2012; 63:606-12. [PMID: 22613839 DOI: 10.1016/j.neuropharm.2012.05.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 05/03/2012] [Accepted: 05/10/2012] [Indexed: 11/23/2022]
Abstract
Calcium-mediated pathologic activation of the cysteine protease calpain has been linked to neurodegenerative disorders such as Alzheimer's disease (AD) through the cleavage of proteolytic substrates that negatively affect neuronal function. Hyperphosphorylation of the microtubule-associated protein tau and the subsequent aggregation of tau filaments resulting in the intracellular formation of neurofibrillary tangles are recognized as key etiological factors in AD pathology. Cyclin-dependent kinase 5 (Cdk5), a major kinase responsible for tau hyperphosphorylation in the AD brain, becomes hyperactivated through calpain-mediated cleavage-conversion of the Cdk5 regulatory protein p35 to p25. In the present study, we examined the effects of the novel small-molecule calpain inhibitor A-705253 in acute models of tau hyperphosphorylation in vitro and in vivo. In hippocampal slices in vitro, lowering medium temperature to 33 °C increased tau phosphorylation in which incubation with A-705253 blocked low temperature-induced tau phosphorylation as measured by Western blot analysis. Pentobarbital-induced hypothermia or acute systemic LPS treatment in normal mice increased tau phosphorylation in hippocampal CA3 mossy fibers, as measured by immunohistochemistry, whereas acute A-705253 pretreatment prevented the stress-induced tau hyperphosphorylation in both models. In support of a Cdk5-mediated mechanism, A-705253 administered for two weeks in the drinking water of six month-old prepathogenic 3x Tg-AD mice resulted in decreased expression of the calpain proteolytic p25 fragment. Taken together, results of these studies suggest that calpain inhibition has potential utility in reducing tau hyperphosphorylation and may represent a novel disease-modifying approach in the treatment of AD.
Collapse
|
37
|
Corticotropin-releasing factor receptor-dependent effects of repeated stress on tau phosphorylation, solubility, and aggregation. Proc Natl Acad Sci U S A 2012; 109:6277-82. [PMID: 22451915 DOI: 10.1073/pnas.1203140109] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Exposure and/or sensitivity to stress have been implicated as conferring risk for development of Alzheimer's disease (AD). Although the basis for such a link remains unclear, we previously reported differential involvement of corticotropin-releasing factor receptor (CRFR) 1 and 2 in acute stress-induced tau phosphorylation (tau-P) and solubility in the hippocampus. Here we examined the role of CRFRs in tau-P induced by repeated stress and the structural manifestations of altered tau solubility. Robust tau-P responses were seen in WT and CRFR2 null mice exposed to repeated stress, which were sustained at even 24 h after the final stress exposure. A portion of phosphorylated tau in these mice was sequestered in detergent-soluble cellular fractions. In contrast, CRFR1 and CRFR double-KO mice did not exhibit repeated stress-induced alterations in tau-P or solubility. Similarly, treatment with CRFR1 antagonist attenuated repeated stress-induced tau-P. Using histochemical approaches in a transgenic CRFR1 reporter mouse line, we found substantial overlap between hippocampal CRFR1 expression and cells positive for phosphorylated tau after exposure to repeated stress. Ultrastructural analysis of negatively stained extracts from WT and CRFR2 null mice identified globular aggregates that displayed positive immunogold labeling for tau-P, as well as conformational changes in tau (MC1) seen in early AD. Given that repeated stress exposure results in chronic increases in hippocampal tau-P and its sequestration in an insoluble (and potentially prepathogenic) form, our data may define a link between stress and an AD-related pathogenic mechanism.
Collapse
|