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Pomilio C, Presa J, Oses C, Vinuesa A, Bentivegna M, Gregosa A, Riudavets M, Sevlever G, Galvan V, Levi V, Beauquis J, Saravia F. Loss of Direct Vascular Contact to Astrocytes in the Hippocampus as an Initial Event in Alzheimer's Disease. Evidence from Patients, In Vivo and In Vitro Experimental Models. Mol Neurobiol 2024; 61:5142-5160. [PMID: 38172288 DOI: 10.1007/s12035-023-03897-5] [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: 08/30/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of aggregated amyloid peptides in the brain parenchyma and within the walls of cerebral vessels. The hippocampus-a complex brain structure with a pivotal role in learning and memory-is implicated in this disease. However, there is limited data on vascular changes during AD pathological degeneration in this susceptible structure, which has distinctive vascular traits. Our aim was to evaluate vascular alterations in the hippocampus of AD patients and PDAPP-J20 mice-a model of AD-and to determine the impact of Aβ40 and Aβ42 on endothelial cell activation. We found a loss of physical astrocyte-endothelium interaction in the hippocampus of individuals with AD as compared to non-AD donors, along with reduced vascular density. Astrocyte-endothelial interactions and levels of the tight junction protein occludin were altered early in PDAPP-J20 mice, preceding any signs of morphological changes or disruption of the blood-brain barrier in these mice. At later stages, PDAPP-J20 mice exhibited decreased vascular density in the hippocampus and leakage of fluorescent tracers, indicating dysfunction of the vasculature and the BBB. In vitro studies showed that soluble Aβ40 exposure in human brain microvascular endothelial cells (HBMEC) was sufficient to induce NFκB translocation to the nucleus, which may be linked with an observed reduction in occludin levels. The inhibition of the membrane receptor for advanced glycation end products (RAGE) prevented these changes in HBMEC. Additional results suggest that Aβ42 indirectly affects the endothelium by inducing astrocytic factors. Furthermore, our results from human and mouse brain samples provide evidence for the crucial involvement of the hippocampal vasculature in Alzheimer's disease.
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Affiliation(s)
- C Pomilio
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - J Presa
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - C Oses
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - A Vinuesa
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - M Bentivegna
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - A Gregosa
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - M Riudavets
- FLENI, Instituto de Investigaciones Neurológicas Dr Raúl Carrea, Buenos Aires, Argentina
| | - G Sevlever
- FLENI, Instituto de Investigaciones Neurológicas Dr Raúl Carrea, Buenos Aires, Argentina
| | - V Galvan
- Department of Biochemistry and Molecular Biology and Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences, Oklahoma City, OK, 73104, USA
| | - V Levi
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - J Beauquis
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - F Saravia
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina.
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina.
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2
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Shoja A, Sani M, Mirzohreh ST, Ebrahimi MJ, Moafi M, Balaghirad N, Jafary H, Sagharichi M, Aalipour MA, Yassaghi Y, Nazerian Y, Moghaddam MH, Bayat AH, Ashraf H, Aliaghaei A, Olyayi PDB. Dental stem cells improve memory and reduce cell death in rat seizure model. Anat Sci Int 2024:10.1007/s12565-024-00781-7. [PMID: 38782867 DOI: 10.1007/s12565-024-00781-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 05/12/2024] [Indexed: 05/25/2024]
Abstract
Epilepsy is a common neurological disorder that significantly affects the quality of life of patients. In this study, we aim to evaluate the effectiveness of dental pulp stem cell (DPSC) transplantation in decreasing inflammation and cell death in brain cells, thus reducing seizure damage. We induced seizures in rats using intraperitoneal injections of pentylenetetrazole (PTZ). In the PTZ + DPSC group, we conducted bilateral hippocampal transplantation of DPSCs in PTZ-lesioned rat models. After 1 month, we performed post-graft analysis and measured some behavioral factors, such as working memory and long-term memory, using a T-maze test and passive avoidance test, respectively. We investigated the immunohistopathology and distribution of astrocyte cells through light microscopy and Sholl analysis. Additionally, we employed the Voronoi tessellation method to estimate the spatial distribution of the cells in the hippocampus. Compared to the control group, we observed a reduction in astrogliosis, astrocyte process length, the number of branches, and intersections distal to the soma in the hippocampus of the PTZ + DPSC group. Further analysis indicated that the grafted DPSCs decreased the expression of caspase-3 in the hippocampus of rats with induced seizures. Moreover, the DPSCs transplant protected hippocampal pyramidal neurons against PTZ toxicity and improved the spatial distribution of the hippocampal neurons. Our findings suggest that DPSCs transplant can be an effective modifier of astrocyte reactivation and inflammatory responses.
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Affiliation(s)
- Aliakbar Shoja
- Department of Endodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mojtaba Sani
- Integrative Brain Health and Wellness, Neuroscience, Neuronutrition, Psychology, Rehabilitation and Physiotherapy, Neurocognitive, Cognitive Enhancement, Brain Health Optimization, SNSI-Sanineurosapiens Institute, Hanover, Germany
| | | | - Mohammad Javad Ebrahimi
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maral Moafi
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nika Balaghirad
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hosein Jafary
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mastoore Sagharichi
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Amin Aalipour
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Younes Yassaghi
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Yasaman Nazerian
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Meysam Hassani Moghaddam
- Department of Anatomical Sciences, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran.
| | - Amir-Hossein Bayat
- Department of Basic Sciences, Saveh University of Medical Sciences, Saveh, Iran
- Department of Neuroscience, School of Sciences and Advanced Technology in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Hengameh Ashraf
- Department of Endodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Aliaghaei
- Hearing Disorders Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Nagayach A, Wang C. Autophagy in neural stem cells and glia for brain health and diseases. Neural Regen Res 2024; 19:729-736. [PMID: 37843206 PMCID: PMC10664120 DOI: 10.4103/1673-5374.382227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 06/19/2023] [Accepted: 07/14/2023] [Indexed: 10/17/2023] Open
Abstract
Autophagy is a multifaceted cellular process that not only maintains the homeostatic and adaptive responses of the brain but is also dynamically involved in the regulation of neural cell generation, maturation, and survival. Autophagy facilities the utilization of energy and the microenvironment for developing neural stem cells. Autophagy arbitrates structural and functional remodeling during the cell differentiation process. Autophagy also plays an indispensable role in the maintenance of stemness and homeostasis in neural stem cells during essential brain physiology and also in the instigation and progression of diseases. Only recently, studies have begun to shed light on autophagy regulation in glia (microglia, astrocyte, and oligodendrocyte) in the brain. Glial cells have attained relatively less consideration despite their unquestioned influence on various aspects of neural development, synaptic function, brain metabolism, cellular debris clearing, and restoration of damaged or injured tissues. Thus, this review composes pertinent information regarding the involvement of autophagy in neural stem cells and glial regulation and the role of this connexion in normal brain functions, neurodevelopmental disorders, and neurodegenerative diseases. This review will provide insight into establishing a concrete strategic approach for investigating pathological mechanisms and developing therapies for brain diseases.
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Affiliation(s)
- Aarti Nagayach
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Chenran Wang
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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4
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Elgazzaz M, Berdasco C, Garai J, Baddoo M, Lu S, Daoud H, Zabaleta J, Mauvais-Jarvis F, Lazartigues E. Maternal Western diet programs cardiometabolic dysfunction and hypothalamic inflammation via epigenetic mechanisms predominantly in the male offspring. Mol Metab 2024; 80:101864. [PMID: 38159883 PMCID: PMC10806294 DOI: 10.1016/j.molmet.2023.101864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 12/04/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024] Open
Abstract
OBJECTIVE Maternal exposure during pregnancy is a strong determinant of offspring health outcomes. Such exposure induces changes in the offspring epigenome resulting in gene expression and functional changes. In this study, we investigated the effect of maternal Western hypercaloric diet (HCD) programming during the perinatal period on neuronal plasticity and cardiometabolic health in adult offspring. METHODS C57BL/6J dams were fed HCD for 1 month prior to mating with regular diet (RD) sires and kept on the same diet throughout pregnancy and lactation. At weaning, offspring were maintained on either HCD or RD for 3 months resulting in 4 treatment groups that underwent cardiometabolic assessments. DNA and RNA were extracted from the hypothalamus to perform whole genome methylation, mRNA, and miRNA sequencing followed by bioinformatic analyses. RESULTS Maternal programming resulted in male-specific hypertension and hyperglycemia, with both males and females showing increased sympathetic tone to the vasculature. Surprisingly, programmed male offspring fed HCD in adulthood exhibited lower glucose levels, less insulin resistance, and leptin levels compared to non-programmed HCD-fed male mice. Hypothalamic genes involved in inflammation and type 2 diabetes were targeted by differentially expressed miRNA, while genes involved in glial and astrocytic differentiation were differentially methylated in programmed male offspring. These data were supported by our findings of astrogliosis, microgliosis and increased microglial activation in programmed males in the paraventricular nucleus (PVN). Programming induced a protective effect in male mice fed HCD in adulthood, resulting in lower protein levels of hypothalamic TGFβ2, NF-κB2, NF-κBp65, Ser-pIRS1, and GLP1R compared to non-programmed HCD-fed males. Although TGFβ2 was upregulated in male mice exposed to HCD pre- or post-natally, only blockade of the brain TGFβ receptor in RD-HCD mice improved glucose tolerance and a trend to weight loss. CONCLUSIONS Our study shows that maternal HCD programs neuronal plasticity in the offspring and results in male-specific hypertension and hyperglycemia associated with hypothalamic inflammation in mechanisms and pathways distinct from post-natal HCD exposure. Together, our data unmask a compensatory role of HCD programming, likely via priming of metabolic pathways to handle excess nutrients in a more efficient way.
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Affiliation(s)
- Mona Elgazzaz
- Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Health Care System, New Orleans, LA 70119, USA; Genetics Unit, Department of Histology and Cell Biology, Faculty of Medicine, Suez Canal University, Ismailia, 41522, Egypt
| | - Clara Berdasco
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Health Care System, New Orleans, LA 70119, USA
| | - Jone Garai
- Department of Interdisciplinary Oncology and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Melody Baddoo
- Department of Pathology and Laboratory Medicine/Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Shiping Lu
- Center for Translational Research in Infection and Inflammation, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Hisham Daoud
- School of Computer and Cyber Sciences, Augusta University, Augusta, GA 30901, USA
| | - Jovanny Zabaleta
- Department of Interdisciplinary Oncology and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Franck Mauvais-Jarvis
- Southeast Louisiana Veterans Health Care System, New Orleans, LA 70119, USA; Department of Medicine, Section of Endocrinology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Eric Lazartigues
- Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Health Care System, New Orleans, LA 70119, USA; Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
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5
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Zeng X, Cheung SKK, Shi M, Or PMY, Li Z, Liu JYH, Ho WLH, Liu T, Lu K, Rudd JA, Wang Y, Chan AM. Astrocyte-specific knockout of YKL-40/Chi3l1 reduces Aβ burden and restores memory functions in 5xFAD mice. J Neuroinflammation 2023; 20:290. [PMID: 38042775 PMCID: PMC10693711 DOI: 10.1186/s12974-023-02970-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/24/2023] [Indexed: 12/04/2023] Open
Abstract
Glial cell-mediated neuroinflammation and neuronal attrition are highly correlated with cognitive impairment in Alzheimer's disease. YKL-40 is a secreted astrocytic glycoprotein that serves as a diagnostic biomarker of Alzheimer's disease. High levels of YKL-40 are associated with either advanced Alzheimer's disease or the normal aging process. However, the functional role of YKL-40 in Alzheimer's disease development has not been firmly established. In a 5xFAD mouse model of Alzheimer's disease, we observed increased YKL-40 expression in the cerebrospinal fluid of 7-month-old mice and was correlated with activated astrocytes. In primary astrocytes, Aβ1-42 upregulated YKL-40 in a dose-dependent manner and was correlated with PI3-K signaling pathway activation. Furthermore, primary neurons treated with YKL-40 and/or Aβ1-42 resulted in significant synaptic degeneration, reduced dendritic complexity, and impaired electrical parameters. More importantly, astrocyte-specific knockout of YKL-40 over a period of 7 days in symptomatic 5xFAD mice could effectively reduce amyloid plaque deposition in multiple brain regions. This was also associated with attenuated glial activation, reduced neuronal attrition, and restored memory function. These biological phenotypes could be explained by enhanced uptake of Aβ1-42 peptides, increased rate of Aβ1-42 degradation and acidification of lysosomal compartment in YKL-40 knockout astrocytes. Our results provide new insights into the role of YKL-40 in Alzheimer's disease pathogenesis and demonstrate the potential of targeting this soluble biomarker to alleviate cognitive defects in symptomatic Alzheimer's disease patients.
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Affiliation(s)
- Xiaoyan Zeng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Room G03, Lo Kwee-Seong Integrated Biomedical Sciences Building, Hong Kong SAR, China
| | - Stanley K K Cheung
- School of Biomedical Sciences, The Chinese University of Hong Kong, Room G03, Lo Kwee-Seong Integrated Biomedical Sciences Building, Hong Kong SAR, China
- Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Mengqi Shi
- School of Life Science and Technology, Weifang Medical University, Shandong, China
| | - Penelope M Y Or
- School of Biomedical Sciences, The Chinese University of Hong Kong, Room G03, Lo Kwee-Seong Integrated Biomedical Sciences Building, Hong Kong SAR, China
| | - Zhining Li
- School of Biomedical Sciences, The Chinese University of Hong Kong, Room G03, Lo Kwee-Seong Integrated Biomedical Sciences Building, Hong Kong SAR, China
| | - Julia Y H Liu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Room G03, Lo Kwee-Seong Integrated Biomedical Sciences Building, Hong Kong SAR, China
| | - Wayne L H Ho
- School of Biomedical Sciences, The Chinese University of Hong Kong, Room G03, Lo Kwee-Seong Integrated Biomedical Sciences Building, Hong Kong SAR, China
| | - Tian Liu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Room G03, Lo Kwee-Seong Integrated Biomedical Sciences Building, Hong Kong SAR, China
| | - Kun Lu
- School of Life Science and Technology, Weifang Medical University, Shandong, China
| | - John A Rudd
- School of Biomedical Sciences, The Chinese University of Hong Kong, Room G03, Lo Kwee-Seong Integrated Biomedical Sciences Building, Hong Kong SAR, China
| | - Yubing Wang
- School of Life Science and Technology, Weifang Medical University, Shandong, China.
| | - Andrew M Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Room G03, Lo Kwee-Seong Integrated Biomedical Sciences Building, Hong Kong SAR, China.
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6
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Wang X, Xie Y, Chen G, Lu Y, Wang D, Zhu L. Intermittent hypoxia therapy ameliorates beta-amyloid pathology via TFEB-mediated autophagy in murine Alzheimer's disease. J Neuroinflammation 2023; 20:240. [PMID: 37864249 PMCID: PMC10588168 DOI: 10.1186/s12974-023-02931-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 10/12/2023] [Indexed: 10/22/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder. Impaired autophagy in plaque-associated microglia (PAM) has been reported to accelerate amyloid plaque deposition and cognitive impairment in AD pathogenesis. Recent evidence suggests that the transcription factor EB (TFEB)-mediated activation of the autophagy-lysosomal pathway is a promising treatment approach for AD. Moreover, the complementary therapy of intermittent hypoxia therapy (IHT) has been shown to upregulate autophagy and impart beneficial effects in patients with AD. However, the effect of IHT on PAM remains unknown. METHODS 8-Month-old APP/PS1 mice were treated with IHT for 28 days. Spatial learning memory capacity and anxiety in mice were investigated. AD pathology was determined by the quantity of nerve fibers and synapses density, numbers of microglia and neurons, Aβ plaque deposition, pro-inflammatory factors, and the content of Aβ in the brain. TFEB-mediated autophagy was determined by western blot and qRT-PCR. Primary microglia were treated with oligomeric Aβ 1-42 (oAβ) combined with IHT for mechanism exploration. Differential genes were screened by RNA-seq. Autophagic degradation process of intracellular oAβ was traced by immunofluorescence. RESULTS In this study, we found that IHT ameliorated cognitive function by attenuating neuronal loss and axonal injury in an AD animal model (APP/PS1 mice) with beta-amyloid (Aβ) pathology. In addition, IHT-mediated neuronal protection was associated with reduced Aβ accumulation and plaque formation. Using an in vitro PAM model, we further confirmed that IHT upregulated autophagy-related proteins, thereby promoting the Aβ autophagic degradation by PAM. Mechanistically, IHT facilitated the nuclear localization of TFEB in PAM, with TFEB activity showing a positive correlation with Aβ degradation by PAM in vivo and in vitro. In addition, IHT-induced TFEB activation was associated with the inhibition of the AKT-MAPK-mTOR pathway. CONCLUSIONS These results suggest that IHT alleviates neuronal damage and neuroinflammation via the upregulation of TFEB-dependent Aβ clearance by PAM, leading to improved learning and memory in AD mice. Therefore, IHT may be a promising non-pharmacologic therapy in complementary medicine against AD.
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Affiliation(s)
- Xueting Wang
- Institute of Special Environmental Medicine, Co-Innovation Center of Neuroregeneration, Nantong University, No. 9, Seyuan Road, Chongchuan District, Nantong, 226009, Jiangsu, China.
| | - Yuqi Xie
- Institute of Special Environmental Medicine, Co-Innovation Center of Neuroregeneration, Nantong University, No. 9, Seyuan Road, Chongchuan District, Nantong, 226009, Jiangsu, China
| | - Guijuan Chen
- Institute of Special Environmental Medicine, Co-Innovation Center of Neuroregeneration, Nantong University, No. 9, Seyuan Road, Chongchuan District, Nantong, 226009, Jiangsu, China
| | - Yapeng Lu
- Institute of Special Environmental Medicine, Co-Innovation Center of Neuroregeneration, Nantong University, No. 9, Seyuan Road, Chongchuan District, Nantong, 226009, Jiangsu, China
| | - Dan Wang
- Institute of Special Environmental Medicine, Co-Innovation Center of Neuroregeneration, Nantong University, No. 9, Seyuan Road, Chongchuan District, Nantong, 226009, Jiangsu, China
| | - Li Zhu
- Institute of Special Environmental Medicine, Co-Innovation Center of Neuroregeneration, Nantong University, No. 9, Seyuan Road, Chongchuan District, Nantong, 226009, Jiangsu, China.
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Ullah R, Lee EJ. Advances in Amyloid-β Clearance in the Brain and Periphery: Implications for Neurodegenerative Diseases. Exp Neurobiol 2023; 32:216-246. [PMID: 37749925 PMCID: PMC10569141 DOI: 10.5607/en23014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/25/2023] [Accepted: 08/23/2023] [Indexed: 09/27/2023] Open
Abstract
This review examines the role of impaired amyloid-β clearance in the accumulation of amyloid-β in the brain and the periphery, which is closely associated with Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA). The molecular mechanism underlying amyloid-β accumulation is largely unknown, but recent evidence suggests that impaired amyloid-β clearance plays a critical role in its accumulation. The review provides an overview of recent research and proposes strategies for efficient amyloid-β clearance in both the brain and periphery. The clearance of amyloid-β can occur through enzymatic or non-enzymatic pathways in the brain, including neuronal and glial cells, blood-brain barrier, interstitial fluid bulk flow, perivascular drainage, and cerebrospinal fluid absorption-mediated pathways. In the periphery, various mechanisms, including peripheral organs, immunomodulation/immune cells, enzymes, amyloid-β-binding proteins, and amyloid-β-binding cells, are involved in amyloid-β clearance. Although recent findings have shed light on amyloid-β clearance in both regions, opportunities remain in areas where limited data is available. Therefore, future strategies that enhance amyloid-β clearance in the brain and/or periphery, either through central or peripheral clearance approaches or in combination, are highly encouraged. These strategies will provide new insight into the disease pathogenesis at the molecular level and explore new targets for inhibiting amyloid-β deposition, which is central to the pathogenesis of sporadic AD (amyloid-β in parenchyma) and CAA (amyloid-β in blood vessels).
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Affiliation(s)
- Rahat Ullah
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, School of Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Neurology, School of Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA
| | - Eun Jeong Lee
- Department of Brain Science, Ajou University School of Medicine, Suwon 16499, Korea
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Luo D, Ye W, Chen L, Yuan X, Zhang Y, Chen C, Jin X, Zhou Y. PPARα Inhibits Astrocyte Inflammation Activation by Restoring Autophagic Flux after Transient Brain Ischemia. Biomedicines 2023; 11:biomedicines11030973. [PMID: 36979952 PMCID: PMC10045980 DOI: 10.3390/biomedicines11030973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
Astrocyte inflammation activation is an important cause that hinders the recovery of motor function after cerebral ischemia. However, its molecular mechanism has not yet been clearly clarified. The peroxisome proliferator-activated receptor α (PPARα) is a ligand-activated nuclear transcriptional factor. This study aims to further clarify the role of PPARα in astrocyte inflammation activation after cerebral ischemia and to explore the underlying mechanism. Astrocyte activation was induced in an in vivo model by transient middle cerebral artery occlusion (tMCAO) in mice. The in vitro model was induced by an oxygen-glucose deprivation/reoxygenation (OGD/R) in a primary culture of mouse astrocyte. PPARα-deficient mice were used to observe the effects of PPARα on astrocyte activation and autophagic flux. Our results showed that PPARα was mainly expressed in activated astrocytes during the chronic phase of brain ischemia and PPARα dysfunction promoted astrocyte inflammatory activation. After cerebral ischemia, the expressions of LC3-II/I and p62 both increased. Autophagic vesicle accumulation was observed by electron microscopy in astrocytes, and the block of autophagic flux was indicated by an mRFP-GFP-LC3 adenovirus infection assay. A PPARα deficit aggravated the autophagic flux block, while PPARα activation preserved the lysosome function and restored autophagic flux in astrocytes after OGD/R. The autophagic flux blocker bafilomycin A1 and chloroquine antagonized the effect of the PPARα agonist on astrocyte activation inhibition. This study identifies a potentially novel function of PPARα in astrocyte autophagic flux and suggests a therapeutic target for the prevention and treatment of chronic brain ischemic injury.
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Affiliation(s)
- Doudou Luo
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen 361102, China
- Key Laboratory of Chiral Drugs, Xiamen 361102, China
- State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen 361102, China
| | - Wenxuan Ye
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen 361102, China
- Key Laboratory of Chiral Drugs, Xiamen 361102, China
- State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen 361102, China
| | - Ling Chen
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen 361102, China
- Key Laboratory of Chiral Drugs, Xiamen 361102, China
| | - Xiaoqian Yuan
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen 361102, China
- Key Laboratory of Chiral Drugs, Xiamen 361102, China
- State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen 361102, China
| | - Yali Zhang
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen 361102, China
- Key Laboratory of Chiral Drugs, Xiamen 361102, China
| | - Caixia Chen
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen 361102, China
- Key Laboratory of Chiral Drugs, Xiamen 361102, China
| | - Xin Jin
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen 361102, China
- Key Laboratory of Chiral Drugs, Xiamen 361102, China
| | - Yu Zhou
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen 361102, China
- Key Laboratory of Chiral Drugs, Xiamen 361102, China
- State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen 361102, China
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9
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Jha D, Bakker ENTP, Kumar R. Mechanistic and therapeutic role of NLRP3 inflammasome in the pathogenesis of Alzheimer's disease. J Neurochem 2023. [PMID: 36802053 DOI: 10.1111/jnc.15788] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/03/2023] [Accepted: 02/13/2023] [Indexed: 02/20/2023]
Abstract
Alzheimer's disease (AD), a progressive neurodegenerative disorder, has emerged as the most common form of dementia in the elderly. Several pathological hallmarks have been identified, including neuroinflammation. A comprehensive insight into the underlying mechanisms that can fuel the development of novel therapeutic approaches is necessary because of the alarmingly rapid increase in the frequency of incidence. Recently, NLRP3 inflammasome was identified as a critical mediator of neuroinflammation. Activation of nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome by amyloid, neurofibrillary tangles, impaired autophagy and endoplasmic reticulum stress, triggers the release of pro-inflammatory cytokines such as IL-1β and IL-18. Subsequently, these cytokines can promote neurodegeneration and cognitive impairment. It is well established that genetic or pharmacological ablation of NLRP3 alleviates AD-related pathological features in in vitro and in vivo models. Therefore, several synthetic and natural compounds have been identified that exhibit the potential to inhibit NLRP3 inflammasome and alleviate AD-associated pathology. The current review article will highlight the various mechanisms by which activation of NLRP3 inflammation occurs during Alzheimer's disease, and how it influences neuroinflammation, neurodegeneration and cognitive impairment. Moreover, we will summarise the different small molecules that possess the potential to inhibit NLRP3 and can pave the path for developing novel therapeutic interventions for AD.
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Affiliation(s)
- Dhanshree Jha
- Department of Biotechnology, GITAM School of Sciences, GITAM (Deemed to be) University, Vishakhapatnam, India
| | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centre, Location University of Amsterdam, and Amsterdam Neuroscience Research Institute, Amsterdam, the Netherlands
| | - Rahul Kumar
- Department of Biotechnology, GITAM School of Sciences, GITAM (Deemed to be) University, Vishakhapatnam, India.,Department of Biomedical Engineering and Physics, Amsterdam University Medical Centre, Location University of Amsterdam, and Amsterdam Neuroscience Research Institute, Amsterdam, the Netherlands
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10
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Cognitive Deficits Found in a Pro-inflammatory State are Independent of ERK1/2 Signaling in the Murine Brain Hippocampus Treated with Shiga Toxin 2 from Enterohemorrhagic Escherichia coli. Cell Mol Neurobiol 2022:10.1007/s10571-022-01298-1. [PMID: 36227397 DOI: 10.1007/s10571-022-01298-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 10/05/2022] [Indexed: 11/03/2022]
Abstract
Shiga toxin 2 (Stx2) from enterohemorrhagic Escherichia coli (EHEC) produces hemorrhagic colitis, hemolytic uremic syndrome (HUS), and acute encephalopathy. The mortality rate in HUS increases significantly when the central nervous system (CNS) is involved. Besides, EHEC also releases lipopolysaccharide (LPS). Many reports have described cognitive dysfunctions in HUS patients, the hippocampus being one of the brain areas targeted by EHEC infection. In this context, a translational murine model of encephalopathy was employed to establish the deleterious effects of Stx2 and the contribution of LPS in the hippocampus. The purpose of this work is to elucidate the signaling pathways that may activate the inflammatory processes triggered by Stx2, which produces cognitive alterations at the level of the hippocampus. Results demonstrate that Stx2 produced depression-like behavior, pro-inflammatory cytokine release, and NF-kB activation independent of the ERK1/2 signaling pathway, while co-administration of Stx2 and LPS reduced memory index. On the other hand, LPS activated NF-kB dependent on ERK1/2 signaling pathway. Cotreatment of Stx2 with LPS aggravated the pathologic state, while dexamethasone treatment succeeded in preventing behavioral alterations. Our present work suggests that the use of drugs such as corticosteroids or NF-kB signaling inhibitors may serve as neuroprotectors from EHEC infection.
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11
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Zhang NY, Wang TH, Chou CH, Wu KC, Yang CR, Kung FL, Lin CJ. Ibuprofen treatment ameliorates memory deficits in rats with collagen-induced arthritis by normalizing aberrant MAPK/NF-κB and glutamatergic pathways. Eur J Pharmacol 2022; 933:175256. [PMID: 36088983 DOI: 10.1016/j.ejphar.2022.175256] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/22/2022] [Accepted: 09/05/2022] [Indexed: 12/29/2022]
Abstract
Many studies have indicated that the risk of cognitive impairment is higher in patients with rheumatoid arthritis (RA). Additionally, patients with RA may have a lower incidence of cognitive impairment with long-term use of ibuprofen. This study was aimed at investigating the impacts of RA on memory function and the mechanisms that ibuprofen may exhibit to improve memory function in rats with collagen-induced arthritis (CIA). Ibuprofen (30 mg/kg) was given twice daily to CIA rats for two weeks starting from Day 18 following the first immunization. Memory function was measured by the Morris water maze (MWM) test and long-term potentiation (LTP). The proinflammatory cytokine levels and downstream signaling pathways, including mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB), were examined. Furthermore, the glutamatergic system, including glutamate transporters/receptors and brain extracellular levels of glutamate, was investigated. The results showed that the impaired learning memory in CIA rats, examined by the MWM test and LTP, can be ameliorated by ibuprofen treatment. Along with the improvement in memory deficits, ibuprofen attenuated both neuroinflammation and the associated elevated levels of phosphorylated p38, JNK, and p65 in the hippocampus of CIA rats. In addition, the decreased excitatory amino acid transporter 2 level, the increased extracellular glutamate, and the upregulated hippocampal NMDA receptor 2B of CIA rats were all normalized by ibuprofen treatment. These findings suggest that the effect of ibuprofen on the memory improvement in CIA rats is associated with the normalization of the activated MAPK and NF-κB pathways and the aberrant glutamatergic system.
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Affiliation(s)
- Nai-You Zhang
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ting-Hsuan Wang
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ching-Hsuan Chou
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kuo-Chen Wu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chia-Ron Yang
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Fan-Lu Kung
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chun-Jung Lin
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.
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12
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Liu C, Sang Z, Pan H, Wu Q, Qiu Y, Shi J. A Novel Multifunctional 5,6-Dimethoxy-Indanone-Chalcone-Carbamate Hybrids Alleviates Cognitive Decline in Alzheimer’s Disease by Dual Inhibition of Acetylcholinesterase and Inflammation. Front Aging Neurosci 2022; 14:922650. [PMID: 35860673 PMCID: PMC9289467 DOI: 10.3389/fnagi.2022.922650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 06/08/2022] [Indexed: 11/24/2022] Open
Abstract
Backgrounds Alzheimer’s disease (AD) is a multifactorial neurodegenerative disease. The treatment of AD through multiple pathological targets may generate therapeutic efficacy better. The multifunctional molecules that simultaneously hit several pathological targets have been of great interest in the intervention of AD. Methods Here, we combined the chalcone scaffold with carbamate moiety and 5,6-dimethoxy-indanone moiety to generate a novel multi-target-directed ligand (MTDL) molecule (E)-3-((5,6-dimethoxy-1-oxo-1,3-dihydro-2H-inden-2-ylidene)-methyl)phenylethyl(methyl) carbamate (named AP5). In silico approaches were used to virtually predict the binding interaction of AP5 with AChE, the drug-likeness, and BBB penetrance, and later validated by evaluation of pharmacokinetics (PK) in vivo by LC-MS/MS. Moreover, studies were conducted to examine the potential of AP5 for inhibiting AChE and AChE-induced amyloid-β (Aβ) aggregation, attenuating neuroinflammation, and providing neuroprotection in the APP/PS1 model of AD. Results We found that AP5 can simultaneously bind to the peripheral and catalytic sites of AChE by molecular docking. AP5 exhibited desirable pharmacokinetic (PK) characteristics including oral bioavailability (67.2%), >10% brain penetrance, and favorable drug-likeness. AP5 inhibited AChE activity and AChE-induced Aβ aggregation in vivo and in vitro. Further, AP5 lowered Aβ plaque deposition and insoluble Aβ levels in APP/PS1 mice. Moreover, AP5 exerted anti-inflammatory responses by switching microglia to a disease-associated microglia (DAM) phenotype and preventing A1 astrocytes formation. The phagocytic activity of microglial cells to Aβ was recovered upon AP5 treatment. Importantly, chronic AP5 treatment significantly prevented neuronal and synaptic damage and memory deficits in AD mice. Conclusion Together, our work demonstrated that AP5 inhibited the AChE activity, decreased Aβ plaque deposition by interfering Aβ aggregation and promoting microglial Aβ phagocytosis, and suppressed inflammation, thereby rescuing neuronal and synaptic damage and relieving cognitive decline. Thus, AP5 can be a new promising candidate for the treatment of AD.
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Affiliation(s)
- Chan Liu
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Zhipei Sang
- Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Hong Pan
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Qin Wu
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Yu Qiu
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Yu Qiu,
| | - Jingshan Shi
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
- Jingshan Shi,
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13
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Simon M, Wang MX, Ismail O, Braun M, Schindler AG, Reemmer J, Wang Z, Haveliwala MA, O’Boyle RP, Han WY, Roese N, Grafe M, Woltjer R, Boison D, Iliff JJ. Loss of perivascular aquaporin-4 localization impairs glymphatic exchange and promotes amyloid β plaque formation in mice. Alzheimers Res Ther 2022; 14:59. [PMID: 35473943 PMCID: PMC9040291 DOI: 10.1186/s13195-022-00999-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 04/04/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND Slowed clearance of amyloid β (Aβ) is believed to underlie the development of Aβ plaques that characterize Alzheimer's disease (AD). Aβ is cleared in part by the glymphatic system, a brain-wide network of perivascular pathways that supports the exchange of cerebrospinal and brain interstitial fluid. Glymphatic clearance, or perivascular CSF-interstitial fluid exchange, is dependent on the astroglial water channel aquaporin-4 (AQP4) as deletion of Aqp4 in mice slows perivascular exchange, impairs Aβ clearance, and promotes Aβ plaque formation. METHODS To define the role of AQP4 in human AD, we evaluated AQP4 expression and localization in a human post mortem case series. We then used the α-syntrophin (Snta1) knockout mouse model which lacks perivascular AQP4 localization to evaluate the effect that loss of perivascular AQP4 localization has on glymphatic CSF tracer distribution. Lastly, we crossed this line into a mouse model of amyloidosis (Tg2576 mice) to evaluate the effect of AQP4 localization on amyloid β levels. RESULTS In the post mortem case series, we observed that the perivascular localization of AQP4 is reduced in frontal cortical gray matter of subjects with AD compared to cognitively intact subjects. This decline in perivascular AQP4 localization was associated with increasing Aβ and neurofibrillary pathological burden, and with cognitive decline prior to dementia onset. In rodent studies, Snta1 gene deletion slowed CSF tracer influx and interstitial tracer efflux from the mouse brain and increased amyloid β levels. CONCLUSIONS These findings suggest that the loss of perivascular AQP4 localization may contribute to the development of AD pathology in human populations.
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Affiliation(s)
- Matthew Simon
- Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR USA
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR USA
| | - Marie Xun Wang
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR USA
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA USA
| | - Ozama Ismail
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR USA
- Center for Advanced Biomedical Imaging, University College London, London, UK
| | - Molly Braun
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA USA
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, 1660 S Columbian Wy., Seattle, WA 98108 USA
| | - Abigail G. Schindler
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA USA
- VISN 20 Geriatric Research, Education and Clinical Center (GRECC), VA Puget Sound Health Care System, Seattle, WA USA
| | - Jesica Reemmer
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR USA
| | - Zhongya Wang
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR USA
| | - Mariya A. Haveliwala
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, 1660 S Columbian Wy., Seattle, WA 98108 USA
| | - Ryan P. O’Boyle
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, 1660 S Columbian Wy., Seattle, WA 98108 USA
| | - Warren Y. Han
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, 1660 S Columbian Wy., Seattle, WA 98108 USA
| | - Natalie Roese
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR USA
| | - Marjorie Grafe
- Department of Pathology, Oregon Health & Science University, Portland, OR USA
| | - Randall Woltjer
- Department of Pathology, Oregon Health & Science University, Portland, OR USA
| | - Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ USA
| | - Jeffrey J. Iliff
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR USA
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA USA
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, 1660 S Columbian Wy., Seattle, WA 98108 USA
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR USA
- Department of Neurology, University of Washington School of Medicine, Seattle, WA USA
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14
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Turati J, Rudi J, Beauquis J, Carniglia L, López Couselo F, Saba J, Caruso C, Saravia F, Lasaga M, Durand D. A metabotropic glutamate receptor 3 (mGlu3R) isoform playing neurodegenerative roles in astrocytes is prematurely up-regulated in an Alzheimer's model. J Neurochem 2022; 161:366-382. [PMID: 35411603 DOI: 10.1111/jnc.15610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/14/2022] [Accepted: 03/23/2022] [Indexed: 12/26/2022]
Abstract
Subtype 3 metabotropic glutamate receptor (mGlu3R) displays a broad range of neuroprotective effects. We previously demonstrated that mGlu3R activation in astrocytes protects hippocampal neurons from Aβ neurotoxicity through stimulation of both neurotrophin release and Aβ uptake. Alternative-spliced variants of mGlu3R were found in human brains. The most prevalent variant, mGlu3Δ4, lacks exon 4 encoding the transmembrane domain and can inhibit ligand binding to mGlu3R. To date, neither its role in neurodegenerative disorders nor its endogenous expression in CNS cells has been addressed. The present paper describes for the first time an association between altered hippocampal expression of mGlu3Δ4 and Alzheimer's disease (AD) in the preclinical murine model PDAPP-J20, as well as a deleterious effect of mGlu3Δ4 in astrocytes. As assessed by western blot, hippocampal mGlu3R levels progressively decreased with age in PDAPP-J20 mice. On the contrary, mGlu3Δ4 levels were drastically increased with aging in nontransgenic mice, but prematurely over-expressed in 5-month-old PDAPP-J20-derived hippocampi, prior to massive senile plaque deposition. Also, we found that mGlu3Δ4 co-precipitated with mGlu3R mainly in 5-month-old PDAPP-J20 mice. We further showed by western blot that primary cultured astrocytes and neurons expressed mGlu3Δ4, whose levels were reduced by Aβ, thereby discouraging a causal effect of Aβ on mGlu3Δ4 induction. However, heterologous expression of mGlu3Δ4 in astrocytes induced cell death, inhibited mGlu3R expression, and prevented mGlu3R-dependent Aβ glial uptake. Indeed, mGlu3Δ4 promoted neurodegeneration in neuron-glia co-cultures. These results provide evidence of an inhibitory role of mGlu3Δ4 in mGlu3R-mediated glial neuroprotective pathways, which may lie behind AD onset.
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Affiliation(s)
- Juan Turati
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Julieta Rudi
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.,IATIMET Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Juan Beauquis
- Laboratorio de Neurobiología del Envejecimiento, Instituto de Biología y Medicina Experimental (IBYME), CONICET, Buenos Aires, Argentina.,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lila Carniglia
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Federico López Couselo
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Julieta Saba
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Carla Caruso
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Flavia Saravia
- Laboratorio de Neurobiología del Envejecimiento, Instituto de Biología y Medicina Experimental (IBYME), CONICET, Buenos Aires, Argentina.,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mercedes Lasaga
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Daniela Durand
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
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15
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Azad AK, Sheikh AM, Haque MA, Osago H, Sakai H, Shibly AZ, Yano S, Michikawa M, Hossain S, Tabassum S, A. G, Zhou X, Zhang Y, Nagai A. Time-Dependent Analysis of Plasmalogens in the Hippocampus of an Alzheimer's Disease Mouse Model: A Role of Ethanolamine Plasmalogen. Brain Sci 2021; 11:1603. [PMID: 34942905 PMCID: PMC8699479 DOI: 10.3390/brainsci11121603] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 12/26/2022] Open
Abstract
Plasmalogens are alkenyl-acyl glycerophospholipids and decreased in post-mortem Alzheimer's disease (AD) brains. The aim of this study is to investigate the time-dependent changes of plasmalogens in the hippocampus of an AD model mouse (J20). Plasmalogen levels at 3, 6, 9, 12 and 15 months were analyzed by liquid-chromatography-targeted-multiplexed-selected-reaction-monitoring-tandem-mass-spectrometry (LC-SRM/MS). Reactive oxygen species (ROS) levels were evaluated using dichlorofluorescein diacetate (DCF-DA). Plasmalogen synthesizing enzyme glycerone-phosphate O-acyltransferase (GNPAT) and late endosome marker Rab7 levels were quantified by Western blotting. GNPAT localization, changes of neuronal and glial cell numbers were evaluated by immunostaining. Compared to wild-type mice (WT), total plasmalogen-ethanolamine, but not plasmalogen-choline levels, were increased at 9 months and subsequently decreased at 15 months in J20 mice. A principal component analysis of plasmalogen-ethanolamine species could separate WT and J20 mice both at 9 and 15 months. Both GNPAT and Rab7 protein were increased in J20 mice at 9 months, whereas GNPAT was decreased at 15 months. ROS levels were increased in J20 mice except for 9 months. Our results suggest that increased plasmalogen-ethanolamine could counteract ROS levels and contribute to the phagocytosis process in J20 mice at 9 months. Such results might indicate a transient protective response of plasmalogen-ethanolamine in AD conditions.
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Affiliation(s)
- Abul Kalam Azad
- Department of Neurology, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.K.A.); (A.Z.S.); (G.A.); (X.Z.); (Y.Z.)
- Department of Microbiology, Jagannath University, Dhaka 1100, Bangladesh
| | - Abdullah Md. Sheikh
- Department of Laboratory Medicine, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.M.S.); (M.A.H.); (S.Y.); (S.T.)
| | - Md. Ahsanul Haque
- Department of Laboratory Medicine, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.M.S.); (M.A.H.); (S.Y.); (S.T.)
- Department of Pharmacy, University of Asia Pacific, Dhaka 1205, Bangladesh
| | - Harumi Osago
- Department of Biochemistry, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan;
| | - Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan;
| | - Abu Zaffar Shibly
- Department of Neurology, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.K.A.); (A.Z.S.); (G.A.); (X.Z.); (Y.Z.)
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Tangail 1902, Bangladesh
| | - Shozo Yano
- Department of Laboratory Medicine, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.M.S.); (M.A.H.); (S.Y.); (S.T.)
| | - Makoto Michikawa
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan;
| | - Shahdat Hossain
- Department of Biochemistry and Molecular Biology, Jahangirnagar University, Dhaka 1342, Bangladesh;
| | - Shatera Tabassum
- Department of Laboratory Medicine, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.M.S.); (M.A.H.); (S.Y.); (S.T.)
| | - Garu A.
- Department of Neurology, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.K.A.); (A.Z.S.); (G.A.); (X.Z.); (Y.Z.)
| | - Xiaojing Zhou
- Department of Neurology, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.K.A.); (A.Z.S.); (G.A.); (X.Z.); (Y.Z.)
| | - Yuchi Zhang
- Department of Neurology, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.K.A.); (A.Z.S.); (G.A.); (X.Z.); (Y.Z.)
| | - Atsushi Nagai
- Department of Neurology, Faculty of Medicine, Shimane University, Izumo 693-8501, Japan; (A.K.A.); (A.Z.S.); (G.A.); (X.Z.); (Y.Z.)
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16
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Tao L, Liu Q, Zhang F, Fu Y, Zhu X, Weng X, Han H, Huang Y, Suo Y, Chen L, Gao X, Wei X. Microglia modulation with 1070-nm light attenuates Aβ burden and cognitive impairment in Alzheimer's disease mouse model. LIGHT, SCIENCE & APPLICATIONS 2021; 10:179. [PMID: 34493703 PMCID: PMC8423759 DOI: 10.1038/s41377-021-00617-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/29/2021] [Accepted: 08/17/2021] [Indexed: 05/05/2023]
Abstract
Photobiomodulation, by utilizing low-power light in the visible and near-infrared spectra to trigger biological responses in cells and tissues, has been considered as a possible therapeutic strategy for Alzheimer's disease (AD), while its specific mechanisms have remained elusive. Here, we demonstrate that cognitive and memory impairment in an AD mouse model can be ameliorated by 1070-nm light via reducing cerebral β-amyloid (Aβ) burden, the hallmark of AD. The glial cells, including microglia and astrocytes, play important roles in Aβ clearance. Our results show that 1070-nm light pulsed at 10 Hz triggers microglia rather than astrocyte responses in AD mice. The 1070-nm light-induced microglia responses with alteration in morphology and increased colocalization with Aβ are sufficient to reduce Aβ load in AD mice. Moreover, 1070-nm light pulsed at 10 Hz can reduce perivascular microglia and promote angiogenesis to further enhance Aβ clearance. Our study confirms the important roles of microglia and cerebral vessels in the use of 1070-nm light for the treatment of AD mice and provides a framework for developing a novel therapeutic approach for AD.
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Affiliation(s)
- Lechan Tao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Qi Liu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Fuli Zhang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Yuting Fu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Xi Zhu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Xiaofu Weng
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Hongbin Han
- Institute of Medical Technology, Peking University Health Science Center, Beijing, 100191, China
- Department of Radiology, Peking University Third Hospital, Beijing, 100191, China
- Key Lab of Magnetic Resonance Imaging Device and Technique, Beijing, 100191, China
| | - Yong Huang
- Zhejiang Brainhealth Medical Technology Co., Ltd, Hangzhou, 314400, China
| | - Yuanzhen Suo
- Biomedical Pioneering Innovation Center, Peking University, Beijing, 100871, China
- School of Life Sciences, Peking University, Beijing, 100871, China
| | - Liang Chen
- Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, 200040, China.
- Tianqiao and Chrissy Chen Institute for Clinical Translational Research, Huashan Hospital, Shanghai, 200040, China.
| | - Xiaoling Gao
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Xunbin Wei
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China.
- Institute of Medical Technology, Peking University Health Science Center, Beijing, 100191, China.
- Biomedical Engineering Department, Peking University, Beijing, 100081, China.
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital & Institute, Beijing, 100142, China.
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17
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He Z, Li X, Han S, Ren B, Hu X, Li N, Du X, Ni J, Yang X, Liu Q. Bis(ethylmaltolato)oxidovanadium (IV) attenuates amyloid-beta-mediated neuroinflammation by inhibiting NF-κB signaling pathway via a PPARγ-dependent mechanism. Metallomics 2021; 13:6298233. [PMID: 34124763 DOI: 10.1093/mtomcs/mfab036] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 12/21/2022]
Abstract
Neuroinflammation plays a pivotal role in the pathophysiology of neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. During brain neuroinflammation, activated microglial cells resulting from amyloid-beta (Aβ) overload trigger toxic proinflammatory responses. Bis(ethylmaltolato)oxidovanadium (BEOV) (IV), an important vanadium compound, has been reported to have anti-diabetic, anti-cancer, and neuroprotective effects, but its anti-inflammatory property has rarely been investigated. In the present study, the inhibitory effects of BEOV on neuroinflammation were revealed in both Aβ-stimulated BV2 microglial cell line and APPswe/PS1E9 transgenic mouse brain. BEOV administration significantly decreased the levels of tumor necrosis factor-α, interleukin-6, interleukin-1β, inducible nitric oxide synthase, and cyclooxygenase-2 both in the hippocampus of APPswe/PS1E9 mice and in the Aβ-stimulated BV2 microglia. Furthermore, BEOV suppressed the Aβ-induced activation of nuclear factor-κB (NF-κB) signaling and upregulated the protein expression level of peroxisome proliferator-activated receptor gamma (PPARγ) in a dose-dependent manner. PPARγ inhibitor GW9662 could eliminate the effect of BEOV on Aβ-induced NF-κB activation and proinflammatory mediator production. Taken altogether, these findings suggested that BEOV ameliorates Aβ-stimulated neuroinflammation by inhibiting NF-κB signaling pathway through a PPARγ-dependent mechanism.
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Affiliation(s)
- Zhijun He
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518060, China.,Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China
| | - Xiaoqian Li
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518060, China
| | - Shuangxue Han
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430073, China
| | - Bingyu Ren
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518060, China
| | - Xia Hu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430073, China
| | - Nan Li
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518060, China.,Shenzhen Bay Laboratory, Shenzhen, 518055, China
| | - Xiubo Du
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518060, China.,Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China
| | - Jiazuan Ni
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518060, China.,Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China
| | - Xiaogai Yang
- State Key Laboratories of Natural and Biomimetic Drugs, Department of Chemical Biology, Peking University School of Pharmaceutical Sciences, Beijing, 100191, China
| | - Qiong Liu
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518060, China.,Shenzhen Bay Laboratory, Shenzhen, 518055, China
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18
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Limegrover CS, LeVine H, Izzo NJ, Yurko R, Mozzoni K, Rehak C, Sadlek K, Safferstein H, Catalano SM. Alzheimer's protection effect of A673T mutation may be driven by lower Aβ oligomer binding affinity. J Neurochem 2021; 157:1316-1330. [PMID: 33025581 PMCID: PMC8246829 DOI: 10.1111/jnc.15212] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 12/16/2022]
Abstract
Several mutations conferring protection against Alzheimer's disease (AD) have been described, none as profound as the A673T mutation, where carriers are four times less likely to get AD compared to noncarriers. This mutation results in reduced amyloid beta (Aβ) protein production in vitro and lower lifetime Aβ concentration in carriers. Better understanding of the protective mechanisms of the mutation may provide important insights into AD pathophysiology and identify productive therapeutic intervention strategies for disease modification. Aβ(1-42) protein forms oligomers that bind saturably to a single receptor site on neuronal synapses, initiating the downstream toxicities observed in AD. Decreased formation, toxicity, or stability of soluble Aβ oligomers, or reduction of synaptic binding of these oligomers, may combine with overall lower Aβ concentration to underlie A673T's disease protecting mechanism. To investigate these possibilities, we compared the formation rate of soluble oligomers made from Icelandic A673T mutant and wild type (wt) Aβ(1-42) synthetic protein, the amount and intensity of oligomer bound to mature primary rat hippocampal/cortical neuronal synapses, and the potency of bound oligomers to impact trafficking rate in neurons in vitro using a physiologically relevant oligomer preparation method. At equal protein concentrations, mutant protein forms approximately 50% or fewer oligomers of high molecular weight (>50 kDa) compared to wt protein. Mutant oligomers are twice as potent at altering the cellular vesicle trafficking rate as wt at equivalent concentrations, however, mutant oligomers have a >4-fold lower binding affinity to synaptic receptors (Kd = 1,950 vs. 442 nM). The net effect of these differences is a lower overall toxicity at a given concentration. This study demonstrates for the first time that mutant A673T Aβ oligomers prepared with this method have fundamentally different assembly characteristics and biological impact from wt protein and indicates that its disease protecting mechanism may result primarily from the mutant protein's much lower binding affinity to synaptic receptors. This suggests that therapeutics that effectively reduce oligomer binding to synapses in the brain may be beneficial in AD.
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Affiliation(s)
| | - Harry LeVine
- Sanders‐Brown Center on AgingUniversity of KentuckyLexingtonKYUSA
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19
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Marques DA, Gargaglioni LH, Joseph V, Bretzner F, Bícego KC, Fournier S, Kinkead R. Impact of ovariectomy and CO 2 inhalation on microglia morphology in select brainstem and hypothalamic areas regulating breathing in female rats. Brain Res 2021; 1756:147276. [PMID: 33422531 DOI: 10.1016/j.brainres.2021.147276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/22/2020] [Accepted: 01/02/2021] [Indexed: 11/17/2022]
Abstract
The neural network that regulates breathing shows a significant sexual dimorphism. Ovarian hormones contribute to this distinction as, in rats, ovariectomy reduces the ventilatory response to CO2. Microglia are neuroimmune cells that are sensitive to neuroendocrine changes in their environment. When reacting to challenging conditions, these cells show changes in their morphology that reflect an augmented capacity for producing pro- and anti-inflammatory cytokines. Based on evidence suggesting that microglia contribute to sex-based differences in reflexive responses to hypercapnia, we hypothesized that ovariectomy and hypercapnia promote microglial reactivity in selected brain areas that regulate breathing. We used ionized calcium-binding-adapter molecule-1 (Iba1) immunolabeling to compare the density and morphology of microglia in the locus coeruleus (LC), the caudal medullary raphe, the caudal part of the nucleus of the tractus solitarius (cNTS), and the paraventricular nucleus of the hypothalamus (PVN). Tissue was obtained from SHAM (metaestrus) female rats or following ovariectomy. Rats were exposed to normocapnia or hypercapnia (5% CO2, 20 min). Ovariectomy and hypercapnia did not affect microglial density in any of the structures studied. Ovariectomy promoted a reactive phenotype in the cNTS and LC, as indicated by a larger morphological index. In these structures, hypercapnia had a relatively modest opposing effect; the medullary raphe or the PVN were not affected. We conclude that ovarian hormones attenuate microglial reactivity in CO2/H+ sensing structures. These data suggest that microglia may contribute to neurological diseases in which anomalies of respiratory control are associated with cyclic fluctuations of ovarian hormones or menopause.
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Affiliation(s)
- Danuzia A Marques
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada.
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Vincent Joseph
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Frédéric Bretzner
- Département de Psychiatrie et Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Stéphanie Fournier
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Richard Kinkead
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada
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20
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Signal transduction associated with lead-induced neurological disorders: A review. Food Chem Toxicol 2021; 150:112063. [PMID: 33596455 DOI: 10.1016/j.fct.2021.112063] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 12/28/2022]
Abstract
Lead is a heavy metal pollutant that is widely present in the environment. It affects every organ system, yet the nervous system appears to be the most sensitive and primary target. Although many countries have made significant strides in controlling Pb pollution, Pb poisoning continuous to be a major public health concern. Exposure to Pb causes neurotoxicity that ranges from neurodevelopmental disorders to severe neurodegenerative lesions, leading to impairments in learning, memory, and cognitive function. Studies on the mechanisms of Pb-induced nervous system injury have convincingly shown that this metal can affect a plethora of cellular pathways affecting on cell survival, altering calcium dyshomeostasis, and inducing apoptosis, inflammation, energy metabolism disorders, oxidative stress, autophagy and glial stress. This review summarizes recent knowledge on multiple signaling pathways associated with Pb-induced neurological disorders in vivo and in vitro.
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21
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Lai PH, Wang TH, Zhang NY, Wu KC, Yao CCJ, Lin CJ. Changes of blood-brain-barrier function and transfer of amyloid beta in rats with collagen-induced arthritis. J Neuroinflammation 2021; 18:35. [PMID: 33516259 PMCID: PMC7847579 DOI: 10.1186/s12974-021-02086-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 01/15/2021] [Indexed: 12/20/2022] Open
Abstract
Background Rheumatoid arthritis (RA) is characterized by synovial inflammation, cartilage damage, and systemic inflammation. RA is also associated with the occurrence of neuroinflammation and neurodegenerative diseases. In this study, the impacts of RA on the function of the blood-brain barrier (BBB) and the disposition of amyloid beta (Aβ), including BBB transport and peripheral clearance of Aβ, were investigated in rats with collagen-induced arthritis (CIA), an animal model with similarity to clinical and pathological features of human RA. Methods CIA was induced in female Lewis rats. In addition to neuroinflammation, the integrity and function of the BBB were examined. The expression of Aβ-transporting proteins at brain blood vessels was measured. Blood-to-brain influx and plasma clearance of Aβ were determined. Results Both microgliosis and astrogliosis were significantly increased in the brain of CIA rats, compared with controls. In terms of BBB function, the BBB permeability of sodium fluorescein, a marker compound for BBB integrity, was significantly increased in CIA rats. Moreover, increased expression of matrix metalloproteinase-3 (MMP-3) and MMP-9 and decreased expression of tight junction proteins, zonula occludens-1 (ZO-1) and occludin, were observed in brain microvessels of CIA rats. In related to BBB transport of Aβ, protein expression of the receptor of advanced glycation end product (RAGE) and P-glycoprotein (P-gp) was significantly increased in brain microvessels of CIA rats. Notably, much higher expression of RAGE was identified at the arterioles of the hippocampus of CIA rats. Following an intravenous injection of human Aβ, significant higher brain influx of Aβ was observed in the hippocampus of CIA rats. Conclusions Neuroinflammation and the changes of BBB function were observed in CIA rats. The increased RAGE expression at cerebral blood vessels and enhanced blood-to-brain influx of Aβ indicate the imbalanced BBB clearance of Aβ in RA. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02086-2.
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Affiliation(s)
- Po-Hsuan Lai
- School of Pharmacy, College of Medicine, National Taiwan University, 33 Linsen South Road, Taipei, Taiwan
| | - Ting-Hsuan Wang
- School of Pharmacy, College of Medicine, National Taiwan University, 33 Linsen South Road, Taipei, Taiwan
| | - Nai-You Zhang
- School of Pharmacy, College of Medicine, National Taiwan University, 33 Linsen South Road, Taipei, Taiwan
| | - Kuo-Chen Wu
- School of Pharmacy, College of Medicine, National Taiwan University, 33 Linsen South Road, Taipei, Taiwan
| | - Chung-Chen Jane Yao
- Graduate Institute of Clinical Dentistry, Dental School, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chun-Jung Lin
- School of Pharmacy, College of Medicine, National Taiwan University, 33 Linsen South Road, Taipei, Taiwan.
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22
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Mampay M, Velasco-Estevez M, Rolle SO, Chaney AM, Boutin H, Dev KK, Moeendarbary E, Sheridan GK. Spatiotemporal immunolocalisation of REST in the brain of healthy ageing and Alzheimer's disease rats. FEBS Open Bio 2020; 11:146-163. [PMID: 33185010 PMCID: PMC7780110 DOI: 10.1002/2211-5463.13036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 10/25/2020] [Accepted: 11/04/2020] [Indexed: 12/30/2022] Open
Abstract
In the brain, REST (Repressor Element‐1 Silencing Transcription factor) is a key regulator of neuron cell‐specific gene expression. Nuclear translocation of neuronal REST has been shown to be neuroprotective in a healthy ageing context. In contrast, inability to upregulate nuclear REST is thought to leave ageing neurons vulnerable to neurodegenerative stimuli, such as Alzheimer’s disease (AD) pathology. Hippocampal and cortical neurons are known to be particularly susceptible to AD‐associated neurodegeneration. However, REST expression has not been extensively characterised in the healthy ageing brain. Here, we examined the spatiotemporal immunolocalisation of REST in the brains of healthy ageing wild‐type Fischer‐344 and transgenic Alzheimer’s disease rats (TgF344‐AD). Nuclear expression of REST increased from 6 months to 18 months of age in the hippocampus, frontal cortex and subiculum of wild‐type rats, but not in TgF344‐AD rats. No changes in REST were measured in more posterior cortical regions or in the thalamus. Interestingly, levels of the presynaptic marker synaptophysin, a known gene target of REST, were lower in CA1 hippocampal neurons of 18‐month TgF344‐AD rats compared to 18‐month wild‐types, suggesting that elevated nuclear REST may protect against synapse loss in the CA1 of 18‐month wild‐type rats. High REST expression in ageing wild‐type rats did not, however, protect against axonal loss nor against astroglial reactivity in the hippocampus. Taken together, our data confirm that changes in nuclear REST expression are context‐, age‐ and brain region‐specific. Moreover, key brain structures involved in learning and memory display elevated REST expression in healthy ageing wild‐type rats but not TgF344‐AD rats.
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Affiliation(s)
- Myrthe Mampay
- School of Pharmacy and Biomolecular Sciences, University of Brighton, UK
| | - María Velasco-Estevez
- Drug Development, Department of Physiology, School of Medicine, Trinity College Dublin, Ireland
| | - Sara O Rolle
- The Sainsbury Welcome Centre for Neural Circuits and Behaviour, University College London, UK
| | - Aisling M Chaney
- Faculty of Biology, Medicine and Health, School of Health Sciences, Division of Informatics, Imaging and Data Sciences, University of Manchester, UK
| | - Hervé Boutin
- Wolfson Molecular Imaging Centre, University of Manchester, UK.,Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, UK
| | - Kumlesh K Dev
- Drug Development, Department of Physiology, School of Medicine, Trinity College Dublin, Ireland
| | | | - Graham K Sheridan
- School of Life Sciences, Queens Medical Centre, University of Nottingham, UK
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23
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Severe reactive astrocytes precipitate pathological hallmarks of Alzheimer's disease via H 2O 2- production. Nat Neurosci 2020; 23:1555-1566. [PMID: 33199896 DOI: 10.1038/s41593-020-00735-y] [Citation(s) in RCA: 150] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 10/07/2020] [Indexed: 12/29/2022]
Abstract
Although the pathological contributions of reactive astrocytes have been implicated in Alzheimer's disease (AD), their in vivo functions remain elusive due to the lack of appropriate experimental models and precise molecular mechanisms. Here, we show the importance of astrocytic reactivity on the pathogenesis of AD using GiD, a newly developed animal model of reactive astrocytes, where the reactivity of astrocytes can be manipulated as mild (GiDm) or severe (GiDs). Mechanistically, excessive hydrogen peroxide (H2O2) originated from monoamine oxidase B in severe reactive astrocytes causes glial activation, tauopathy, neuronal death, brain atrophy, cognitive impairment and eventual death, which are significantly prevented by AAD-2004, a potent H2O2 scavenger. These H2O2--induced pathological features of AD in GiDs are consistently recapitulated in a three-dimensional culture AD model, virus-infected APP/PS1 mice and the brains of patients with AD. Our study identifies H2O2 from severe but not mild reactive astrocytes as a key determinant of neurodegeneration in AD.
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24
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Presa JL, Saravia F, Bagi Z, Filosa JA. Vasculo-Neuronal Coupling and Neurovascular Coupling at the Neurovascular Unit: Impact of Hypertension. Front Physiol 2020; 11:584135. [PMID: 33101063 PMCID: PMC7546852 DOI: 10.3389/fphys.2020.584135] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/04/2020] [Indexed: 12/18/2022] Open
Abstract
Components of the neurovascular unit (NVU) establish dynamic crosstalk that regulates cerebral blood flow and maintain brain homeostasis. Here, we describe accumulating evidence for cellular elements of the NVU contributing to critical physiological processes such as cerebral autoregulation, neurovascular coupling, and vasculo-neuronal coupling. We discuss how alterations in the cellular mechanisms governing NVU homeostasis can lead to pathological changes in which vascular endothelial and smooth muscle cell, pericyte and astrocyte function may play a key role. Because hypertension is a modifiable risk factor for stroke and accelerated cognitive decline in aging, we focus on hypertension-associated changes on cerebral arteriole function and structure, and the molecular mechanisms through which these may contribute to cognitive decline. We gather recent emerging evidence concerning cognitive loss in hypertension and the link with vascular dementia and Alzheimer’s disease. Collectively, we summarize how vascular dysfunction, chronic hypoperfusion, oxidative stress, and inflammatory processes can uncouple communication at the NVU impairing cerebral perfusion and contributing to neurodegeneration.
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Affiliation(s)
- Jessica L Presa
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States.,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - Flavia Saravia
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - Zsolt Bagi
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Jessica A Filosa
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States
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25
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Belaya I, Ivanova M, Sorvari A, Ilicic M, Loppi S, Koivisto H, Varricchio A, Tikkanen H, Walker FR, Atalay M, Malm T, Grubman A, Tanila H, Kanninen KM. Astrocyte remodeling in the beneficial effects of long-term voluntary exercise in Alzheimer's disease. J Neuroinflammation 2020; 17:271. [PMID: 32933545 PMCID: PMC7493971 DOI: 10.1186/s12974-020-01935-w] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/19/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Increased physical exercise improves cognitive function and reduces pathology associated with Alzheimer's disease (AD). However, the mechanisms underlying the beneficial effects of exercise in AD on the level of specific brain cell types remain poorly investigated. The involvement of astrocytes in AD pathology is widely described, but their exact role in exercise-mediated neuroprotection warrant further investigation. Here, we investigated the effect of long-term voluntary physical exercise on the modulation of the astrocyte state. METHODS Male 5xFAD mice and their wild-type littermates had free access to a running wheel from 1.5 to 7 months of age. A battery of behavioral tests was used to assess the effects of voluntary exercise on cognition and learning. Neuronal loss, impairment in neurogenesis, beta-amyloid (Aβ) deposition, and inflammation were evaluated using a variety of histological and biochemical measurements. Sophisticated morphological analyses were performed to delineate the specific involvement of astrocytes in exercise-induced neuroprotection in the 5xFAD mice. RESULTS Long-term voluntary physical exercise reversed cognitive impairment in 7-month-old 5xFAD mice without affecting neurogenesis, neuronal loss, Aβ plaque deposition, or microglia activation. Exercise increased glial fibrillary acid protein (GFAP) immunoreactivity and the number of GFAP-positive astrocytes in 5xFAD hippocampi. GFAP-positive astrocytes in hippocampi of the exercised 5xFAD mice displayed increases in the numbers of primary branches and in the soma area. In general, astrocytes distant from Aβ plaques were smaller in size and possessed simplified processes in comparison to plaque-associated GFAP-positive astrocytes. Morphological alterations of GFAP-positive astrocytes occurred concomitantly with increased astrocytic brain-derived neurotrophic factor (BDNF) and restoration of postsynaptic protein PSD-95. CONCLUSIONS Voluntary physical exercise modulates the reactive astrocyte state, which could be linked via astrocytic BDNF and PSD-95 to improved cognition in 5xFAD hippocampi. The molecular pathways involved in this modulation could potentially be targeted for benefit against AD.
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Affiliation(s)
- Irina Belaya
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Mariia Ivanova
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Annika Sorvari
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Marina Ilicic
- School of Biomedical Sciences and Pharmacy and the Priority Research Centre for Stroke and Brain Injury, The University of Newcastle, University Dr, Callaghan, NSW, 2308, Australia
| | - Sanna Loppi
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Hennariikka Koivisto
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Alessandra Varricchio
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Heikki Tikkanen
- Institute of Biomedicine, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Frederick R Walker
- School of Biomedical Sciences and Pharmacy and the Priority Research Centre for Stroke and Brain Injury, The University of Newcastle, University Dr, Callaghan, NSW, 2308, Australia
| | - Mustafa Atalay
- Institute of Biomedicine, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Tarja Malm
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Alexandra Grubman
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Melbourne, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Australia
| | - Heikki Tanila
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland
| | - Katja M Kanninen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland.
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26
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Activate or Inhibit? Implications of Autophagy Modulation as a Therapeutic Strategy for Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21186739. [PMID: 32937909 PMCID: PMC7554997 DOI: 10.3390/ijms21186739] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 12/19/2022] Open
Abstract
Neurodegenerative diseases result in a range of conditions depending on the type of proteinopathy, genes affected or the location of the degeneration in the brain. Proteinopathies such as senile plaques and neurofibrillary tangles in the brain are prominent features of Alzheimer’s disease (AD). Autophagy is a highly regulated mechanism of eliminating dysfunctional organelles and proteins, and plays an important role in removing these pathogenic intracellular protein aggregates, not only in AD, but also in other neurodegenerative diseases. Activating autophagy is gaining interest as a potential therapeutic strategy for chronic diseases featuring protein aggregation and misfolding, including AD. Although autophagy activation is a promising intervention, over-activation of autophagy in neurodegenerative diseases that display impaired lysosomal clearance may accelerate pathology, suggesting that the success of any autophagy-based intervention is dependent on lysosomal clearance being functional. Additionally, the effects of autophagy activation may vary significantly depending on the physiological state of the cell, especially during proteotoxic stress and ageing. Growing evidence seems to favour a strategy of enhancing the efficacy of autophagy by preventing or reversing the impairments of the specific processes that are disrupted. Therefore, it is essential to understand the underlying causes of the autophagy defect in different neurodegenerative diseases to explore possible therapeutic approaches. This review will focus on the role of autophagy during stress and ageing, consequences that are linked to its activation and caveats in modulating this pathway as a treatment.
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27
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Tan X, Guan H, Yang Y, Luo S, Hou L, Chen H, Li J. Cu(II) disrupts autophagy-mediated lysosomal degradation of oligomeric Aβ in microglia via mTOR-TFEB pathway. Toxicol Appl Pharmacol 2020; 401:115090. [DOI: 10.1016/j.taap.2020.115090] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 05/19/2020] [Accepted: 06/01/2020] [Indexed: 01/02/2023]
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28
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Xu CJ, Wang JL, Jing-Pan, Min-Liao. Tph2 Genetic Ablation Contributes to Senile Plaque Load and Astrogliosis in APP/PS1 Mice. Curr Alzheimer Res 2020; 16:219-232. [PMID: 30827242 DOI: 10.2174/1567205016666190301110110] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/20/2018] [Accepted: 01/11/2019] [Indexed: 01/06/2023]
Abstract
BACKGROUND Amyloid-β (Aβ) accumulation plays a critical role in the pathogenesis of Alzheimer's disease (AD) lesions. Deficiency of Serotonin signaling recently has been linked to the increased Aβ level in transgenic mice and humans. In addition, tryptophan hydroxylase-2 (Tph2), a second tryptophan hydroxylase isoform, controls brain serotonin synthesis. However, it remains to be determined that whether Tph2 deficient APP/PS1mice affect the formation of Aβ plaques in vivo. METHODS Both quantitative and qualitative immunochemistry methods, as well as Congo red staining were used to evaluate the Aβ load and astrogliosis in these animals. RESULTS we studied alterations of cortex and hippocampus in astrocytes and senile plaques by Tph2 conditional knockout (Tph2 CKO) AD mice from 6-10 months of age. Using Congo red staining and immunostained with Aβ antibody, we showed that plaques load or plaques numbers significantly increased in Tph2 CKO experimental groups at 8 to 10 months old, compared to wild type (WT) group, respectively. Using GFAP+ astrocytes immunofluorescence method, we found that the density of GFAP+ astrocytes markedly enhanced in Tph2 CKO at 10 months. We showed Aβ plaques co-localized autophagic markers LC3 and p62. Nevertheless, we did not observe any co-localization between GFAP+ astrocytes and autophagic markers, but detected the co-localization between βIII-tubulin+ neurons and autophagic markers. CONCLUSION Overall, our work provides the preliminary evidence in vivo that Tph2 plays a role in amyloid plaques generation.
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Affiliation(s)
- Chao-Jin Xu
- Department of Histology & Embryology, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Jun-Ling Wang
- Centre for Reproductive Medicine, Affiliated Hospital 1 of Wenzhou Medical University, Wenzhou, Zhejiang 325000, China
| | - Jing-Pan
- Department of Histology & Embryology, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Min-Liao
- Department of Histology & Embryology, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
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Zhang X, Lao K, Qiu Z, Rahman MS, Zhang Y, Gou X. Potential Astrocytic Receptors and Transporters in the Pathogenesis of Alzheimer's Disease. J Alzheimers Dis 2020; 67:1109-1122. [PMID: 30741675 DOI: 10.3233/jad-181084] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia and is characterized by the progressive loss of memory and cognition in the aging population. However, the etiology of and therapies for AD remain far from understood. Astrocytes, the most abundant neuroglia in the brain, have recently aroused substantial concern due to their involvement in synaptotoxicity, amyloidosis, neuroinflammation, and oxidative stress. In this review, we summarize the candidate molecules of astrocytes, especially receptors and transporters, that may be involved in AD pathogenesis. These molecules include excitatory amino acid transporters (EAATs), metabotropic glutamate receptor 5 (mGluR5), the adenosine 2A receptor (A2AR), the α7-nicotinic acetylcholine receptor (α7-nAChR), the calcium-sensing receptor (CaSR), S100β, and cannabinoid receptors. We describe the characteristics of these molecules and the neurological and pharmacological underpinnings of these molecules in AD. Among these molecules, EAATs, A2AR, and mGluR5 are strongly related to glutamate-mediated synaptotoxicity and are involved in glutamate transmission or the clearance of extrasynaptic glutamate in the AD brain. The α7-nAChR, CaSR, and mGluR5 are receptors of Aβ and can induce a plethora of toxic effects, such as the production of excess Aβ, synaptotoxicity, and NO production triggered by changes in intracellular calcium signaling. Antagonists or positive allosteric modulators of these receptors can repair cognitive ability and modify neurobiological changes. Moreover, blocking S100β or activating cannabinoid receptors reduces neuroinflammation, oxidative stress, and reactive astrogliosis. Thus, targeting these molecules might provide alternative approaches for treating AD.
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Affiliation(s)
- Xiaohua Zhang
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, P.R. China
| | - Kejing Lao
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, P.R. China
| | - Zhongying Qiu
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, P.R. China
| | - Md Saidur Rahman
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, P.R. China.,Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, P.R. China
| | - Yuelin Zhang
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, P.R. China
| | - Xingchun Gou
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, P.R. China
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30
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Multiple inflammatory profiles of microglia and altered neuroimages in APP/PS1 transgenic AD mice. Brain Res Bull 2020; 156:86-104. [DOI: 10.1016/j.brainresbull.2020.01.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/14/2019] [Accepted: 01/03/2020] [Indexed: 12/11/2022]
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31
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McKee CA, Lananna BV, Musiek ES. Circadian regulation of astrocyte function: implications for Alzheimer's disease. Cell Mol Life Sci 2020; 77:1049-1058. [PMID: 31578625 PMCID: PMC7098845 DOI: 10.1007/s00018-019-03314-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/26/2019] [Accepted: 09/19/2019] [Indexed: 12/13/2022]
Abstract
The circadian clock regulates rhythms in gene transcription that have a profound impact on cellular function, behavior, and disease. Circadian dysfunction is a symptom of aging and neurodegenerative diseases, and recent studies suggest a bidirectional relationship between impaired clock function and neurodegeneration. Glial cells possess functional circadian clocks which may serve to control glial responses to daily oscillations in brain activity, cellular stress, and metabolism. Astrocytes directly support brain function through synaptic interactions, neuronal metabolic support, neuroinflammatory regulation, and control of neurovascular coupling at blood and CSF barriers. Emerging evidence suggests that the astrocyte circadian clock may be involved in many of these processes, and that clock disruption could influence neurodegeneration by disrupting several aspects of astrocyte function. Here we review the literature surrounding circadian control of astrocyte function in health and disease, and discuss the potential implications of astrocyte clocks for neurodegeneration.
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Affiliation(s)
- Celia A McKee
- Department of Neurology, Washington University School of Medicine, Box 8111, 425 S. Euclid Ave, St. Louis, MO, 63105, USA
| | - Brian V Lananna
- Department of Neurology, Washington University School of Medicine, Box 8111, 425 S. Euclid Ave, St. Louis, MO, 63105, USA
| | - Erik S Musiek
- Department of Neurology, Washington University School of Medicine, Box 8111, 425 S. Euclid Ave, St. Louis, MO, 63105, USA.
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32
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Pomilio C, Gorojod RM, Riudavets M, Vinuesa A, Presa J, Gregosa A, Bentivegna M, Alaimo A, Alcon SP, Sevlever G, Kotler ML, Beauquis J, Saravia F. Microglial autophagy is impaired by prolonged exposure to β-amyloid peptides: evidence from experimental models and Alzheimer's disease patients. GeroScience 2020; 42:613-632. [PMID: 31975051 DOI: 10.1007/s11357-020-00161-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/16/2020] [Indexed: 01/17/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the presence of misfolded proteins, amyloid-β (Aβ) aggregates, and neuroinflammation in the brain. Microglial cells are key players in the context of AD, being capable of releasing cytokines in response to Aβ and degrading aggregated proteins by mechanisms involving the ubiquitin-proteasome system and autophagy. Here, we present in vivo and in vitro evidence showing that microglial autophagy is affected during AD progression. PDAPPJ20 mice-murine model of AD-exhibited an accumulation of the autophagy receptor p62 and ubiquitin+ aggregates in Iba1+ microglial cells close to amyloid deposits in the hippocampus. Moreover, cultured microglial BV-2 cells showed an enhanced autophagic flux during a 2-h exposure to fibrillar Aβ, which was decreased if the exposure was prolonged to 24 h, a condition analogous to the chronic exposure to Aβ in the human pathology. The autophagic impairment was also associated with lysosomal damage, depicted by membrane permeabilization as shown by the presence of the acid hydrolase cathepsin-D in cytoplasm and altered LysoTracker staining. These results are compatible with microglial exhaustion caused by pro-inflammatory conditions and persistent exposure to aggregated Aβ peptides. In addition, we found LC3-positive autophagic vesicles accumulated in phagocytic CD68+ microglia in human AD brain samples, suggesting defective autophagy in microglia of AD brain. Our results indicate that the capacity of microglia to degrade Aβ and potentially other proteins through autophagy may be negatively affected as the disease progresses. Preserving autophagy in microglia thus emerges as a promising approach for treating AD. Graphical abstract.
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Affiliation(s)
- Carlos Pomilio
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental (IBYME), CONICET, Obligado 2490, 1428, Buenos Aires, Argentina
| | - Roxana M Gorojod
- Departmento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IQUIBICEN, CONICET, Buenos Aires, Argentina
| | - Miguel Riudavets
- FLENI, Instituto de Investigaciones Neurológicas Dr Raúl Carrea, Buenos Aires, Argentina
| | - Angeles Vinuesa
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental (IBYME), CONICET, Obligado 2490, 1428, Buenos Aires, Argentina
| | - Jessica Presa
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental (IBYME), CONICET, Obligado 2490, 1428, Buenos Aires, Argentina
| | - Amal Gregosa
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental (IBYME), CONICET, Obligado 2490, 1428, Buenos Aires, Argentina
| | - Melisa Bentivegna
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental (IBYME), CONICET, Obligado 2490, 1428, Buenos Aires, Argentina
| | - Agustina Alaimo
- Departmento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IQUIBICEN, CONICET, Buenos Aires, Argentina
| | - Soledad Porte Alcon
- Departmento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IQUIBICEN, CONICET, Buenos Aires, Argentina
| | - Gustavo Sevlever
- FLENI, Instituto de Investigaciones Neurológicas Dr Raúl Carrea, Buenos Aires, Argentina
| | - Monica L Kotler
- Departmento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IQUIBICEN, CONICET, Buenos Aires, Argentina
| | - Juan Beauquis
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental (IBYME), CONICET, Obligado 2490, 1428, Buenos Aires, Argentina
| | - Flavia Saravia
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental (IBYME), CONICET, Obligado 2490, 1428, Buenos Aires, Argentina.
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Sung K, Jimenez-Sanchez M. Autophagy in Astrocytes and its Implications in Neurodegeneration. J Mol Biol 2020; 432:2605-2621. [PMID: 31931011 DOI: 10.1016/j.jmb.2019.12.041] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/12/2019] [Accepted: 12/18/2019] [Indexed: 12/12/2022]
Abstract
Autophagy is a major degradation pathway where double-membrane vesicles called autophagosomes deliver cytoplasmic content to the lysosome. Increasing evidence suggests that autophagy dysfunction contributes to the pathogenesis of neurodegenerative diseases. In addition, misfolded proteins that accumulate in these diseases and constitute a common pathological hallmark are substrates for autophagic degradation. Astrocytes, a major type of glial cells, are emerging as a critical component in most neurodegenerative diseases. This review will summarize the recent efforts to investigate the role that autophagy plays in astrocytes in the context of neurodegenerative diseases. While the field has mostly focused on the implications of autophagy in neurons, autophagy may also be involved in the clearance of disease-related proteins in astrocytes as well as in maintaining astrocyte function, which could impact the cell autonomous and non-cell autonomous contribution of astrocytes to neurodegeneration.
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Affiliation(s)
- Katherine Sung
- King's College London, Institute of Psychiatry, Psychology & Neuroscience, Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe Road, London, SE5 9RX, UK
| | - Maria Jimenez-Sanchez
- King's College London, Institute of Psychiatry, Psychology & Neuroscience, Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe Road, London, SE5 9RX, UK.
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34
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Tang RH, Qi RQ, Liu HY. Interleukin-4 affects microglial autophagic flux. Neural Regen Res 2019; 14:1594-1602. [PMID: 31089059 PMCID: PMC6557092 DOI: 10.4103/1673-5374.255975] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/24/2019] [Indexed: 12/15/2022] Open
Abstract
Interleukin-4 plays an important protective role in Alzheimer's disease by regulating microglial phenotype, phagocytosis of amyloid-β, and secretion of anti-inflammatory and neurotrophic cytokines. Recently, increasing evidence has suggested that autophagy regulates innate immunity by affecting M1/M2 polarization of microglia/macrophages. However, the role of interleukin-4 in microglial autophagy is unknown. In view of this, BV2 microglia were treated with 0, 10, 20 or 50 ng/mL interleukin-4 for 24, 48, or 72 hours. Subsequently, light chain 3-II and p62 protein expression levels were detected by western blot assay. BV2 microglia were incubated with interleukin-4 (20 ng/mL, experimental group), 3-methyladenine (500 μM, autophagy inhibitor, negative control group), rapamycin (100 nM, autophagy inductor, positive control group), 3-methyladenine + interleukin-4 (rescue group), or without treatment for 24 hours, and then exposed to amyloid-β (1 μM, model group) or vehicle control (control) for 24 hours. LC3-II and p62 protein expression levels were again detected by western blot assay. In addition, expression levels of multiple markers of M1 and M2 phenotype were assessed by real-time fluorescence quantitative polymerase chain reaction, while intracellular and supernatant amyloid-β protein levels were measured by enzyme-linked immunosorbent assay. Our results showed that interleukin-4 induced microglial autophagic flux, most significantly at 20 ng/mL for 48 hours. Interleukin-4 pretreated microglia inhibited blockade of amyloid-β-induced autophagic flux, and promoted amyloid-β uptake and degradation partly through autophagic flux, but inhibited switching of amyloid-β-induced M1 phenotype independent on autophagic flux. These results indicate that interleukin-4 pretreated microglia increases uptake and degradation of amyloid-β in a process partly mediated by autophagy, which may play a protective role against Alzheimer's disease.
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Affiliation(s)
- Run-Hong Tang
- Department of Neurology, the First Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Rui-Qun Qi
- Department of Dermatology, Key Laboratory of Immunodermatology, the First Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Hua-Yan Liu
- Department of Neurology, the First Hospital of China Medical University, Shenyang, Liaoning Province, China
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35
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Liu J, Li L. Targeting Autophagy for the Treatment of Alzheimer's Disease: Challenges and Opportunities. Front Mol Neurosci 2019; 12:203. [PMID: 31507373 PMCID: PMC6713911 DOI: 10.3389/fnmol.2019.00203] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 08/02/2019] [Indexed: 12/28/2022] Open
Abstract
Alzheimer's disease (AD) is the most common type of dementia which characterized by a progressive loss of memory and cognitive function due to degeneration of synapses and axons. Currently, there is no cure for AD. Deposition of extracellular amyloid-β (Aβ) plaques and intracellular tau neurofibrillary tangles (NFTs) are two hallmark pathologic changes in the brains of Alzheimer's patients. Autophagy is the major mechanism in cells responsible for removing protein aggregates. Accumulation of immature autophagic vacuoles (AVs) in dystrophic neurites of Alzheimer patients' brains suggests that autophagy process is disrupted. Till now, it is far from clear what role autophagy plays in AD, a causative role, a protective role, or just a consequence of the disease process itself. To design more effective therapeutic strategies towards this devastating disorder, it is essential to understand the exact role of autophagy played during different stages of AD.
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Affiliation(s)
- Jie Liu
- Translational Center for Stem Cell Research, Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Lian Li
- Translational Center for Stem Cell Research, Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
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36
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Gregosa A, Vinuesa Á, Todero MF, Pomilio C, Rossi SP, Bentivegna M, Presa J, Wenker S, Saravia F, Beauquis J. Periodic dietary restriction ameliorates amyloid pathology and cognitive impairment in PDAPP-J20 mice: Potential implication of glial autophagy. Neurobiol Dis 2019; 132:104542. [PMID: 31351172 DOI: 10.1016/j.nbd.2019.104542] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/30/2019] [Accepted: 07/22/2019] [Indexed: 12/29/2022] Open
Abstract
Dietary restriction promotes cell regeneration and stress resistance in multiple models of human diseases. One of the conditions that could potentially benefit from this strategy is Alzheimer's disease, a chronic, progressive and prevalent neurodegenerative disease. Although there are no effective pharmacological treatments for this pathology, lifestyle interventions could play therapeutic roles. Our objectives were 1) to evaluate the effects of dietary restriction on cognition, hippocampal amyloid deposition, adult neurogenesis and glial reactivity and autophagy in a mouse model of familial Alzheimer's disease, and 2) to analyze the role of glial cells mediating the effects of nutrient restriction in an in vitro model. Therefore, we established a periodic dietary restriction protocol in adult female PDAPP-J20 transgenic mice for 6 weeks. We found that dietary restriction, not involving overall caloric restriction, attenuated cognitive deficits, amyloid pathology and microglial reactivity in transgenic mice when compared with ad libitum-fed transgenic animals. Also, transgenic mice showed an increase in the astroglial positive signal for LC3, an autophagy-associated protein. In parallel, hippocampal adult neurogenesis was decreased in transgenic mice whereas dietary-restricted transgenic mice showed a neurogenic status similar to controls. In vitro experiments showed that nutrient restriction decreased astroglial and, indirectly, microglial NFκB activation in response to amyloid β peptides. Furthermore, nutrient restriction was able to preserve astroglial autophagic flux and to decrease intracellular amyloid after exposure to amyloid β peptides. Our results suggest neuroprotective effects of nutrient restriction in Alzheimer's disease, with modulation of glial activation and autophagy being potentially involved pathways.
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Affiliation(s)
- Amal Gregosa
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina; Cátedra de Anatomía e Histología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
| | - Ángeles Vinuesa
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - María Florencia Todero
- Laboratorio de Fisiología de los Procesos Inflamatorios, Instituto de Medicina Experimental (IMEX), CONICET, Academia Nacional de Medicina, Buenos Aires, Argentina
| | - Carlos Pomilio
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Soledad P Rossi
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Cátedra de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, Argentina
| | - Melisa Bentivegna
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Jessica Presa
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Shirley Wenker
- Fundación Instituto Leloir-IIBA, CONICET, Buenos Aires, Argentina
| | - Flavia Saravia
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Juan Beauquis
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
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37
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Tenza-Ferrer H, Magno LAV, Romano-Silva MA, da Silva JF, Gomez MV. Phα1β Spider Toxin Reverses Glial Structural Plasticity Upon Peripheral Inflammation. Front Cell Neurosci 2019; 13:306. [PMID: 31354431 PMCID: PMC6635560 DOI: 10.3389/fncel.2019.00306] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 06/24/2019] [Indexed: 01/03/2023] Open
Abstract
The incoming signals from injured sensory neurons upon peripheral inflammation are processed in the dorsal horn of spinal cord, where glial cells accumulate and play a critical role in initiating allodynia (increased pain in response to light-touch). However, how painful stimuli in the periphery engage glial reactivity in the spinal cord remains unclear. Here, we found that a hind paw inflammation induced by CFA produces robust morphological changes in spinal astrocytes and microglia compatible with the reactive phenotype. Strikingly, we discovered that a single intrathecal injection with venom peptides that inhibit calcium channels reversed all the glial pathological features of the peripheral inflammation. These effects were more apparent in rats treated with the Phα1β spider toxin (non-specific calcium channel antagonist) than ω-MVIIA cone snail toxin (selective N-type calcium channel antagonist). These data reveal for the first time a venom peptide acting on glial structural remodeling in vivo. We, therefore, suggest that calcium-dependent plasticity is an essential trigger for glial cells to initiate reactivity, which may represent a new target for the antinociceptive effects of Phα1β and ω-MVIIA toxins in inflammatory pain conditions.
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Affiliation(s)
- Helia Tenza-Ferrer
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Luiz Alexandre Viana Magno
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Marco Aurélio Romano-Silva
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.,Departamento de Saúde Mental, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Juliana Figueira da Silva
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.,Laboratório de Toxinas, Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
| | - Marcus Vinicius Gomez
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.,Laboratório de Toxinas, Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
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Rahman A, Al-Qenaie S, Rao MS, Khan KM, Guillemin GJ. Memantine Is Protective against Cytotoxicity Caused by Lead and Quinolinic Acid in Cultured Rat Embryonic Hippocampal Cells. Chem Res Toxicol 2019; 32:1134-1143. [PMID: 30950269 DOI: 10.1021/acs.chemrestox.8b00421] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Quinolinic acid (QA) is an excitotoxic metabolite of the kynurenine pathway of tryptophan metabolism produced in response to inflammation and oxidative stress. Lead (Pb) causes oxidative stress and thus may produce neurotoxicity by increasing QA production. We investigated the in vitro cytotoxic effects of Pb and QA and the protective effects of the NMDA receptor antagonist memantine. Primary cultures of embryonic hippocampal cells from Wistar rats were treated with different concentrations of Pb, QA, and Pb + QA with and without memantine. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Apoptosis was analyzed by flow cytometry after Annexin-V/propidium iodide staining. The numbers of immunostained neurons (with β3-Tubulin; Tuj1) and astrocytes (with glial fibrillary acidic protein) were counted. Pb at 20 μg/dL (0.97 μM) and QA at 500 nM concentrations showed significant cytotoxic effects, as evidenced by decreased cell viability, increased apoptosis, and a decrease in the number of both astrocytes and neurons. The combination of Pb and QA showed significant synergistic apoptotic effects at lower doses. Memantine (500 nM) was largely protective against the cytotoxic effects of both Pb and QA, suggesting that Pb's and QA's cytotoxicity involves NMDA receptor activation. Whereas the neuroprotection by memantine from QA-induced toxicity has been previously reported, this is the first study reporting the protection by memantine against Pb-induced cytotoxicity in cultured hippocampal cells. Protection by memantine against these neurotoxicants in vivo needs to be investigated.
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Affiliation(s)
- Abdur Rahman
- Department of Food Science and Nutrition, College of Life Sciences , Kuwait University , 13060 Kuwait City , Kuwait
| | - Sara Al-Qenaie
- Department of Food Science and Nutrition, College of Life Sciences , Kuwait University , 13060 Kuwait City , Kuwait.,Kuwait Oil Company Hospital , 61008 Ahmadi , Kuwait
| | - Muddanna S Rao
- Department of Anatomy, Faculty of Medicine , Kuwait University , 13060 Kuwait City , Kuwait
| | - Khalid M Khan
- Department of Anatomy, Faculty of Medicine , Kuwait University , 13060 Kuwait City , Kuwait
| | - Gilles J Guillemin
- Neuroinflammation Group, Faculty of Medicine and Health Sciences , Macquarie University , Macquarie Park , New South Wales 2109 , Australia
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van Weering JRT, Scheper W. Endolysosome and Autolysosome Dysfunction in Alzheimer's Disease: Where Intracellular and Extracellular Meet. CNS Drugs 2019; 33:639-648. [PMID: 31165364 PMCID: PMC6647502 DOI: 10.1007/s40263-019-00643-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Disturbed proteostasis as reflected by a massive accumulation of misfolded protein aggregates is a central feature in Alzheimer's disease. Proteostatic disturbances may be caused by a shift in protein production and clearance. Whereas rare genetic causes of the disease affect the production side, sporadic cases appear to be directed by dysfunction in protein clearance. This review focusses on the involvement of lysosome-mediated clearance. Autophagy is a degradational system where intracellular components are degraded by lysosomal organelles. In addition, "outside-to-inside" trafficking through the endosomes converges with the autolysosomal pathway, thereby bringing together intracellular and extracellular components. Recent findings demonstrate that disturbance in the endo- and autolysosomal pathway induces "inside-to-outside" communication via induction of unconventional secretion, which may bear relevance to the spreading of disease pathology through the brain. The involvement of these pathways in the pathogenesis of the disease is discussed with an outlook to the opportunities it provides for diagnostics as well as therapeutic interventions.
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Affiliation(s)
- Jan R. T. van Weering
- 0000 0004 1754 9227grid.12380.38Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU Faculty of Science, Vrije Universiteit (VU), De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands ,0000000084992262grid.7177.6Department of Clinical Genetics, Amsterdam University Medical Centers Location VUmc, Amsterdam, Netherlands
| | - Wiep Scheper
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU Faculty of Science, Vrije Universiteit (VU), De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands. .,Department of Clinical Genetics, Amsterdam University Medical Centers Location VUmc, Amsterdam, Netherlands. .,Alzheimer Center, Amsterdam University Medical Centers Location VUmc, Amsterdam, Netherlands.
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Early Exposure to a High-Fat Diet Impacts on Hippocampal Plasticity: Implication of Microglia-Derived Exosome-like Extracellular Vesicles. Mol Neurobiol 2018; 56:5075-5094. [PMID: 30474797 DOI: 10.1007/s12035-018-1435-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/15/2018] [Indexed: 12/18/2022]
Abstract
Adolescence is a transitional period from childhood to adulthood characterized by puberty and brain maturation involving behavioral changes and environmental vulnerability. Diet is one of the factors affecting brain health, potentially leading to long-lasting effects. Hence, we studied the impact of early exposure (P21-60) to a high-fat diet (HFD) on mouse hippocampus, analyzing inflammation, adult neurogenesis, dendritic spine plasticity, and spatial memory. Glycemia and seric pro-inflammatory IL1β were higher in HFD mice without differences on body weight. In the HFD hippocampus, neuroinflammation was evidenced by Iba1+ cells reactivity together with a higher expression of TNFα and IL1β while the neurogenic capability in the dentate gyrus was strongly reduced. We found a predominance of immature Dil-labeled dendritic spines from CA1 neurons along with diminished levels of the scaffold protein Shank2, suggesting a defective connectivity. Moreover, the HFD group exhibited spatial memory alterations. To elucidate whether microglia could be mediating HFD-associated neuronal changes, the lipotoxic context was emulated by incubating primary microglia with palmitate, a saturated fatty acid present in HFD. Palmitate induced a pro-inflammatory profile as shown by secreted cytokine levels. The isolated exosome fraction from palmitate-stimulated microglia induced an immature dendritic spine phenotype in primary GFP+ hippocampal neurons, in line with the in vivo findings. These results provide novel data concerning microglia to neuron communication and highlight that fat excess during a short and early period of life could negatively impact on cognition and synaptic plasticity in a neuroinflammatory context, where microglia-derived exosomes could be implicated. Graphical Abstract ᅟ.
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Chia Seed Does Not Improve Cognitive Impairment in SAMP8 Mice Fed with High Fat Diet. Nutrients 2018; 10:nu10081084. [PMID: 30110883 PMCID: PMC6115970 DOI: 10.3390/nu10081084] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/08/2018] [Accepted: 08/10/2018] [Indexed: 11/29/2022] Open
Abstract
Background: Chia seed is an ancient seed with the richest plant source of α-linolenic acid, which has been demonstrated to improve metabolic syndrome associated risk factors. Under high fat diet (HFD) condition, the senescence-accelerated mouse-prone 8 (SAMP8) mice demonstrated worsen Alzheimer’s disease (AD) related pathology compared to low fat diet fed SAMP8 mice. Objective: To explore whether chia seed supplementation might improve cognitive impairment under aging and metabolic stress via high fat diet (HFD) fed SAMP8 mice as a model. Design: SAMP8 mice and senescence-accelerated mouse-resistant 1 (SAMR1) were randomized into 4 groups, i.e., SAMR1 low fat diet group (SAMR1-LFD), SAMP8-HFD and SAMP8-HFD group supplemented with 10% chia seed (SAMP8-HFD+Chia). At the end of the intervention, cognitive function was measured via Morris water maze (MWM) test. Hippocampus and parietal cortex were dissected for further analysis to measure key markers involved AD pathology including Aβ, tau and neuro-inflammation. Results: During navigation trials of MWM test, mice in SAMP8-LFD group demonstrated impaired learning ability compared to SAMR1-LFD group, and chia seed had no effect on learning and memory ability for HFD fed SAMP8 mice. As for Alzheimer’s disease (AD) related pathology, chia seed not only increased α-secretase such as ADAM10 and insulin degrading enzyme (IDE), but also increased β-secretase including beta-secretase 1 (BACE1) and cathepsin B, with an overall effects of elevation in the hippocampal Aβ42 level; chia seed slightly reduced p-Tauser404 in the hippocampus; while an elevation in neuro-inflammation with the activation of glial fibrillary acidic protein (GFAP) and Ibα-1 were observed post chia seed supplementation. Conclusions: Chia seed supplementation did not improve cognitive impairment via MWM in HFD fed SAMP8 mice. This might be associated with that chia seed increased key enzymes involved both in non-amyloidogenic and amyloidogenic pathways, and neuro-inflammation. Future studies are necessary to confirm our present study.
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Jung YJ, Chung WS. Phagocytic Roles of Glial Cells in Healthy and Diseased Brains. Biomol Ther (Seoul) 2018; 26:350-357. [PMID: 29316776 PMCID: PMC6029679 DOI: 10.4062/biomolther.2017.133] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/12/2017] [Accepted: 09/26/2017] [Indexed: 11/10/2022] Open
Abstract
Glial cells are receiving much attention since they have been recognized as important regulators of many aspects of brain function and disease. Recent evidence has revealed that two different glial cells, astrocytes and microglia, control synapse elimination under normal and pathological conditions via phagocytosis. Astrocytes use the MEGF10 and MERTK phagocytic pathways, and microglia use the classical complement pathway to recognize and eliminate unwanted synapses. Notably, glial phagocytosis also contributes to the clearance of disease-specific protein aggregates, such as β-amyloid, huntingtin, and α-synuclein. Here we reivew recent findings showing that glial cells are active regulators in brain functions through phagocytosis and that changes in glial phagocytosis contribute to the pathogenesis of various neurodegenerative diseases. A better understanding of the cellular and molecular mechanisms of glial phagocytosis in healthy and diseased brains will greatly improve our current approach in treating these diseases.
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Affiliation(s)
- Yeon-Joo Jung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Won-Suk Chung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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Li N, Hu P, Xu T, Chen H, Chen X, Hu J, Yang X, Shi L, Luo JH, Xu J. iTRAQ-based Proteomic Analysis of APPSw,Ind Mice Provides Insights into the Early Changes in Alzheimer's Disease. Curr Alzheimer Res 2018; 14:1109-1122. [PMID: 28730955 PMCID: PMC5676024 DOI: 10.2174/1567205014666170719165745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/13/2017] [Accepted: 06/29/2017] [Indexed: 01/17/2023]
Abstract
BACKGROUND Several proteins have been identified as potential diagnostic biomarkers in imaging, genetic, or proteomic studies in Alzheimer disease (AD) patients and mouse models. However, biomarkers for presymptom diagnosis of AD are still under investigation, as are the presymptom molecular changes in AD pathogenesis. OBJECTIVE In this study, we aim to analyzed the early proteomic changes in APPSw,Ind mice and to conduct further functional studies on interesting proteins. METHODS We used the isobaric tags for relative and absolute quantitation (iTRAQ) approach combined with mass spectrometry to examine the early proteomic changes in hippocampi of APPSw,Ind mice. Quantitative reverse transcription polymerase chain reaction (RT-PCR) and immuno-blotting were performed for further validation. Finally, the functions of interesting proteins β-spectrin and Rab3a in APP trafficking and processing were tested by shRNA knockdown, in N2A cells stably expressing β-amyloid precursor protein (APP). RESULTS The iTRAQ and RT-PCR results revealed the detailed molecular changes in oxidative stress, myelination, astrocyte activation, mTOR signaling and Rab3-dependent APP trafficking in the early stage of AD progression. Knock down of β -spectrin and Rab3a finally led to increased APP fragment production, indicating key roles of β-spectrin and Rab3a in regulating APP processing. CONCLUSION Our study provides the first insights into the proteomic changes that occur in the hippocampus in the early stages of the AD mouse model. In addition to improving the understanding of molecular alterations and functional cascades involved in early AD pathogenesis, our findings raise the possibility of developing potential biomarkers and therapeutic targets for early AD.
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Affiliation(s)
- Nan Li
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Pinghong Hu
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Tiantian Xu
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Huan Chen
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Xiaoying Chen
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Jianwen Hu
- Shanghai Applied Protein Technology Co., Ltd., Shanghai. China
| | - Xifei Yang
- Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen. China
| | - Lei Shi
- Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen. China
| | - Jian-Hong Luo
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Junyu Xu
- Center of Neuroscience, Zhejiang University, 866 Yuhangtang Road, Hangzhou. China
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Chung KM, Hernández N, Sproul AA, Yu WH. Alzheimer's disease and the autophagic-lysosomal system. Neurosci Lett 2018; 697:49-58. [PMID: 29758300 DOI: 10.1016/j.neulet.2018.05.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 05/08/2018] [Accepted: 05/10/2018] [Indexed: 02/06/2023]
Abstract
Age-related neurodegenerative diseases are of critical concern to the general population and research/medical community due to their health impact and socioeconomic consequences. A feature of most, if not all, neurodegenerative disorders is the presence of proteinopathies, in which misfolded or conformationally altered proteins drive disease progression and are often used as a primary neuropathological marker of disease. In particular, Alzheimer's disease (AD) is characterized by abnormal accumulation of protein aggregates, primarily extracellular plaques composed of the Aβ peptide and intracellular tangles comprised of the tau protein, both of which may indicate a primary defect in protein clearance. Protein degradation is a key cellular mechanism for protein homeostasis and is essential for cell survival but is disrupted in neurodegenerative diseases. Dysregulation in proteolytic pathways - mainly the autophagic-lysosomal system (A-LS) and the ubiquitin-proteasome system (UPS) - has been increasingly associated with proteinopathies in neurodegenerative diseases. Here we review the role of dysfunctional autophagy underlying AD-related proteinopathy and discuss how to model this aspect of disease, as well as summarize recent advances in translational strategies for targeted A-LS dysfunction in AD.
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Affiliation(s)
- Kyung Min Chung
- Taub Institute and the Department of Pathology & Cell Biology, Columbia University, New York, NY, 10032, United States
| | - Nancy Hernández
- Taub Institute and the Department of Pathology & Cell Biology, Columbia University, New York, NY, 10032, United States
| | - Andrew A Sproul
- Taub Institute and the Department of Pathology & Cell Biology, Columbia University, New York, NY, 10032, United States
| | - Wai Haung Yu
- Taub Institute and the Department of Pathology & Cell Biology, Columbia University, New York, NY, 10032, United States.
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Chidlow G, Wood JPM, Manavis J, Finnie J, Casson RJ. Investigations into Retinal Pathology in the Early Stages of a Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2018; 56:655-675. [PMID: 28035930 PMCID: PMC5271427 DOI: 10.3233/jad-160823] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
There is increasing recognition that visual performance is impaired in early stages of Alzheimer’s disease (AD); however, no consensus exists as to the mechanisms underlying this visual dysfunction, in particular regarding the timing, nature, and extent of retinal versus cortical pathology. If retinal pathology presents sufficiently early, it offers great potential as a source of novel biomarkers for disease diagnosis. The current project utilized an array of immunochemical and molecular tools to perform a characterization of retinal pathology in the early stages of disease progression using a well-validated mouse model of AD (APPSWE/PS1ΔE9). Analytical endpoints included examination of aberrant amyloid and tau in the retina, quantification of any neuronal degeneration, delineation of cellular stress responses of neurons and particularly glial cells, and investigation of oxidative stress. Brain, eyes, and optic nerves were taken from transgenic and wild-type mice of 3 to 12 months of age and processed for immunohistochemistry, qPCR, or western immunoblotting. The results revealed robust expression of the human APP transgene in the retinas of transgenic mice, but a lack of identifiable retinal pathology during the period when amyloid deposits were dramatically escalating in the brain. We were unable to demonstrate the presence of amyloid plaques, dystrophic neurites, neuronal loss, macro- or micro-gliosis, aberrant cell cycle re-entry, oxidative stress, tau hyperphosphorylation, or upregulations of proinflammatory cytokines or stress signaling molecules in the retina. The overall results do not support the hypothesis that detectable retinal pathology occurs concurrently with escalating amyloid deposition in the brains of APPSWE/PS1ΔE9 mice.
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Affiliation(s)
- Glyn Chidlow
- Ophthalmic Research Laboratories, Hanson Institute Centre for Neurological Diseases, Adelaide, SA, Australia.,Department of Ophthalmology and Visual Sciences, University of Adelaide, Adelaide, SA, Australia
| | - John P M Wood
- Ophthalmic Research Laboratories, Hanson Institute Centre for Neurological Diseases, Adelaide, SA, Australia.,Department of Ophthalmology and Visual Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Jim Manavis
- School of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - John Finnie
- School of Medicine, University of Adelaide, Adelaide, SA, Australia.,SA Pathology, Hanson Institute Centre for Neurological Diseases, Adelaide, SA, Australia
| | - Robert J Casson
- Ophthalmic Research Laboratories, Hanson Institute Centre for Neurological Diseases, Adelaide, SA, Australia.,Department of Ophthalmology and Visual Sciences, University of Adelaide, Adelaide, SA, Australia
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Innate immune alterations are elicited in microglial cells before plaque deposition in the Alzheimer's disease mouse model 5xFAD. Sci Rep 2018; 8:1550. [PMID: 29367720 PMCID: PMC5784016 DOI: 10.1038/s41598-018-19699-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/02/2018] [Indexed: 12/26/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia characterized by the formation of amyloid plaques (Aβ). Over the last decade, the important role of the innate immune system for the disease development has been established. Chronic activation of microglial cells creates a proinflammatory environment, which is believed to be central for the development of the disease as well as its progression. We used the AD mouse model 5xFAD to investigate if inflammatory alterations are present in microglial cells before plaque deposition. We applied mass spectrometry and bioinformation analysis to elucidate early microglial alterations. Interestingly, we found the cytokines IL1β and IL10 to be elevated in the 5xFAD brain after the formation of Aβ plaque at 10 weeks only. Using mass spectrometry analysis of microglial cells with bioinformation analysis, we found JAK/STAT, p38 MAPK and Interleukin pathways affected in microglial cells before plaque deposition at 6 weeks. At 10 weeks, GO analysis showed affected pathways related to interferon-gamma regulation and MAPK pathways. Our study points toward early inflammatory changes in microglial cells even before the accumulation of Aβ.
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Kruse MS, Suarez LG, Coirini H. LXR activation increases the expression of GnRH AND αMSH in the rat hypothalamus in vivo. Neurosci Lett 2018; 664:20-27. [DOI: 10.1016/j.neulet.2017.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/11/2017] [Accepted: 11/07/2017] [Indexed: 11/25/2022]
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Glial Draper Rescues Aβ Toxicity in a Drosophila Model of Alzheimer's Disease. J Neurosci 2017; 37:11881-11893. [PMID: 29109235 DOI: 10.1523/jneurosci.0862-17.2017] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 10/19/2017] [Accepted: 10/23/2017] [Indexed: 12/24/2022] Open
Abstract
Pathological hallmarks of Alzheimer's disease (AD) include amyloid-β (Aβ) plaques, neurofibrillary tangles, and reactive gliosis. Glial cells offer protection against AD by engulfing extracellular Aβ peptides, but the repertoire of molecules required for glial recognition and destruction of Aβ are still unclear. Here, we show that the highly conserved glial engulfment receptor Draper/MEGF10 provides neuroprotection in an AD model of Drosophila (both sexes). Neuronal expression of human Aβ42arc in adult flies results in robust Aβ accumulation, neurodegeneration, locomotor dysfunction, and reduced lifespan. Notably, all of these phenotypes are more severe in draper mutant animals, whereas enhanced expression of glial Draper reverses Aβ accumulation, as well as behavioral phenotypes. We also show that the signal transducer and activator of transcription (Stat92E), c-Jun N-terminal kinase (JNK)/AP-1 signaling, and expression of matrix metalloproteinase-1 (Mmp1) are activated downstream of Draper in glia in response to Aβ42arc exposure. Furthermore, Aβ42-induced upregulation of the phagolysosomal markers Atg8 and p62 was notably reduced in draper mutant flies. Based on our findings, we propose that glia clear neurotoxic Aβ peptides in the AD model Drosophila brain through a Draper/STAT92E/JNK cascade that may be coupled to protein degradation pathways such as autophagy or more traditional phagolysosomal destruction methods.SIGNIFICANCE STATEMENT Alzheimer's disease (AD) and similar dementias are common incurable neurodegenerative disorders in the aging population. As the primary immune responders in the brain, glial cells are implicated as key players in the onset and progression of AD and related disorders. Here we show that the glial engulfment receptor Draper is protective in a Drosophila model of AD, reducing levels of amyloid β (Aβ) peptides, reversing locomotor defects, and extending lifespan. We further show that protein degradation pathways are induced downstream of Draper in AD model flies, supporting a model in which glia engulf and destroy Aβ peptides to reduce amyloid-associated toxicity.
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Importance of Autophagy in Mediating Human Immunodeficiency Virus (HIV) and Morphine-Induced Metabolic Dysfunction and Inflammation in Human Astrocytes. Viruses 2017; 9:v9080201. [PMID: 28788100 PMCID: PMC5580458 DOI: 10.3390/v9080201] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/24/2017] [Accepted: 07/24/2017] [Indexed: 12/11/2022] Open
Abstract
Under physiological conditions, the function of astrocytes in providing brain metabolic support is compromised under pathophysiological conditions caused by human immunodeficiency virus (HIV) and opioids. Herein, we examined the role of autophagy, a lysosomal degradation pathway important for cellular homeostasis and survival, as a potential regulatory mechanism during pathophysiological conditions in primary human astrocytes. Blocking autophagy with small interfering RNA (siRNA) targeting BECN1, but not the Autophagy-related 5 (ATG5) gene, caused a significant decrease in HIV and morphine-induced intracellular calcium release. On the contrary, inducing autophagy pharmacologically with rapamycin further enhanced calcium release and significantly reverted HIV and morphine-decreased glutamate uptake. Furthermore, siBeclin1 caused an increase in HIV-induced nitric oxide (NO) release, while viral-induced NO in astrocytes exposed to rapamycin was decreased. HIV replication was significantly attenuated in astrocytes transfected with siRNA while significantly induced in astrocytes exposed to rapamycin. Silencing with siBeclin1, but not siATG5, caused a significant decrease in HIV and morphine-induced interleukin (IL)-8 and tumor necrosis factor alpha (TNF-α) release, while secretion of IL-8 was significantly induced with rapamycin. Mechanistically, the effects of siBeclin1 in decreasing HIV-induced calcium release, viral replication, and viral-induced cytokine secretion were associated with a decrease in activation of the nuclear factor kappa B (NF-κB) pathway.
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Sapp V, Jain M, Liao R. Viewing Extrinsic Proteotoxic Stress Through the Lens of Amyloid Cardiomyopathy. Physiology (Bethesda) 2017; 31:294-9. [PMID: 27252164 DOI: 10.1152/physiol.00047.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Proteotoxicity refers to toxic stress caused by misfolded proteins of extrinsic or intrinsic origin and plays an integral role in the pathogenesis of cardiovascular diseases. Herein, we provide an overview of the current understanding of mechanisms underlying proteotoxicity and its contribution in the pathogenesis of amyloid cardiomyopathy.
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Affiliation(s)
- Valerie Sapp
- Departments of Medicine & Pharmacology, University of California San Diego, San Diego, California; and
| | - Mohit Jain
- Departments of Medicine & Pharmacology, University of California San Diego, San Diego, California; and
| | - Ronglih Liao
- Division of Genetics and Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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