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Lim SL, Tran DN, Kieu Z, Chen C, Villanueva E, Ghiaar S, Gallup V, Zumkehr J, Cribbs DH, Rodriguez-Ortiz CJ, Kitazawa M. Genetic Ablation of Hematopoietic Cell Kinase Accelerates Alzheimer's Disease-Like Neuropathology in Tg2576 Mice. Mol Neurobiol 2020; 57:2447-2460. [PMID: 32146679 DOI: 10.1007/s12035-020-01894-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 02/14/2020] [Indexed: 01/31/2023]
Abstract
Microglial dysregulation, pertaining to impairment in phagocytosis, clearance and containment of amyloid-β (Aβ), and activation of neuroinflammation, has been posited to contribute to the pathogenesis of Alzheimer's disease (AD). Detailed cellular mechanisms that are disrupted during the disease course to display such impairment in microglia, however, remain largely undetermined. We hypothesize that loss of hematopoietic cell kinase (HCK), a phagocytosis-regulating member of the Src family tyrosine kinases that mediate signals from triggering receptor expressed on myeloid cells 2 and other immunoreceptors, impairs microglial homeostasis and Aβ clearance, leading to the accelerated buildup of Aβ pathology and cognitive decline during the early stage of neuropathological development. To elucidate the pivotal role of HCK in AD, we generated a constitutive knockout of HCK in the Tg2576 mouse model of AD. We found that HCK deficiency accelerated cognitive decline along with elevated Aβ level and plaque burden, attenuated microglial Aβ phagocytosis, induced iNOS expression in microglial clusters, and reduced pre-synaptic protein at the hippocampal regions. Our findings substantiate that HCK plays a prominent role in regulating microglial neuroprotective functions and attenuating early AD neuropathology.
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Affiliation(s)
- Siok Lam Lim
- Department of Medicine, Center for Occupational and Environmental Health, University of California, Irvine, CA, 92617, USA.,Molecular and Cell Biology, University of California, Merced, CA, 95343, USA
| | - Diana Nguyen Tran
- Molecular and Cell Biology, University of California, Merced, CA, 95343, USA
| | - Zanett Kieu
- Molecular and Cell Biology, University of California, Merced, CA, 95343, USA
| | - Christine Chen
- Molecular and Cell Biology, University of California, Merced, CA, 95343, USA
| | - Emmanuel Villanueva
- Molecular and Cell Biology, University of California, Merced, CA, 95343, USA
| | - Sagar Ghiaar
- Molecular and Cell Biology, University of California, Merced, CA, 95343, USA
| | - Victoria Gallup
- Molecular and Cell Biology, University of California, Merced, CA, 95343, USA
| | - Joannee Zumkehr
- Department of Medicine, Center for Occupational and Environmental Health, University of California, Irvine, CA, 92617, USA.,Molecular and Cell Biology, University of California, Merced, CA, 95343, USA
| | - David H Cribbs
- Department of Neurology, University of California, Irvine, CA, 92697, USA
| | - Carlos J Rodriguez-Ortiz
- Department of Medicine, Center for Occupational and Environmental Health, University of California, Irvine, CA, 92617, USA.,Molecular and Cell Biology, University of California, Merced, CA, 95343, USA
| | - Masashi Kitazawa
- Department of Medicine, Center for Occupational and Environmental Health, University of California, Irvine, CA, 92617, USA. .,Molecular and Cell Biology, University of California, Merced, CA, 95343, USA.
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Cerovic M, Forloni G, Balducci C. Neuroinflammation and the Gut Microbiota: Possible Alternative Therapeutic Targets to Counteract Alzheimer's Disease? Front Aging Neurosci 2019; 11:284. [PMID: 31680937 PMCID: PMC6813195 DOI: 10.3389/fnagi.2019.00284] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/03/2019] [Indexed: 12/15/2022] Open
Abstract
Alzheimer's disease (AD) is a complex, multi-factorial disease affecting various brain systems. This complexity implies that successful therapies must be directed against several core neuropathological targets rather than single ones. The scientific community has made great efforts to identify the right AD targets beside the historic amyloid-β (Aβ). Neuroinflammation is re-emerging as determinant in the neuropathological process of AD. A new theory, still in its infancy, highlights the role of gut microbiota (GM) in the control of brain development, but also in the onset and progression of neurodegenerative diseases. Bidirectional communication between the central and the enteric nervous systems, called gut-brain axes, is largely influenced by GM and the immune system is a potential key mediator of this interaction. Growing evidence points to the role of GM in the maturation and activation of host microglia and peripheral immune cells. Several recent studies have found abnormalities in GM (dysbiosis) in AD populations. These observations raise the intriguing question whether and how GM dysbiosis could contribute to AD development through action on the immune system and whether, in a therapeutic prospective, the development of strategies preserving a healthy GM might become a valuable approach to prevent AD. Here, we review the evidence from animal models and humans of the role of GM in neuroinflammation and AD.
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Affiliation(s)
- Milica Cerovic
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, IRCCS, Milan, Italy
| | - Gianluigi Forloni
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, IRCCS, Milan, Italy
| | - Claudia Balducci
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, IRCCS, Milan, Italy
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