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Yin T, Yesiltepe M, D'Adamio L. Functional BRI2-TREM2 interactions in microglia: implications for Alzheimer's and related dementias. EMBO Rep 2024; 25:1326-1360. [PMID: 38347225 PMCID: PMC10933458 DOI: 10.1038/s44319-024-00077-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 03/14/2024] Open
Abstract
ITM2B/BRI2 mutations cause Alzheimer's Disease (AD)-related dementias. We observe heightened ITM2B/BRI2 expression in microglia, a pivotal cell type in AD due to risk-increasing variants in the microglial gene TREM2. Single-cell RNA-sequencing demonstrates a Trem2/Bri2-dependent microglia cluster, underscoring their functional interaction. α-secretase cleaves TREM2 into TREM2-CTF and sTREM2. As BRI2 hinders α-secretase cleavage of the AD-related Aβ-Precursor-Protein, we probed whether BRI2 influences TREM2 processing. Our findings indicate a BRI2-TREM2 interaction that inhibits TREM2 processing in heterologous cells. Recombinant BRI2 and TREM2 proteins demonstrate a direct, cell-free BRI2-TREM2 ectodomain interaction. Constitutive and microglial-specific Itm2b-Knock-out mice, and Itm2b-Knock-out primary microglia provide evidence that Bri2 reduces Trem2 processing, boosts Trem2 mRNA expression, and influences Trem2 protein levels through α-secretase-independent pathways, revealing a multifaceted BRI2-TREM2 functional interaction. Moreover, a mutant Itm2b dementia mouse model exhibits elevated Trem2-CTF and sTrem2, mirroring sTREM2 increases in AD patients. Lastly, Bri2 deletion reduces phagocytosis similarly to a pathogenic TREM2 variant that enhances processing. Given BRI2's role in regulating Aβ-Precursor-Protein and TREM2 functions, it holds promise as a therapeutic target for AD and related dementias.
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Affiliation(s)
- Tao Yin
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 205 South Orange Ave, Newark, NJ, 07103, USA.
| | - Metin Yesiltepe
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 205 South Orange Ave, Newark, NJ, 07103, USA
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 205 South Orange Ave, Newark, NJ, 07103, USA.
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D'Adamio L. Transfixed by transgenics: how pathology assumptions are slowing progress in Alzheimer's disease and related dementia research. EMBO Mol Med 2023; 15:e18479. [PMID: 37750482 PMCID: PMC10630870 DOI: 10.15252/emmm.202318479] [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: 08/07/2023] [Revised: 08/31/2023] [Accepted: 09/08/2023] [Indexed: 09/27/2023] Open
Abstract
Model organisms of human diseases are invaluable tools for unraveling pathogenic mechanisms, identifying potential targets for drug development, and evaluating the therapeutic efficacy of candidates in preclinical trials. The utility of model organisms hinges upon their ability to faithfully replicate the underlying pathogenic mechanisms of the human disease. For rodent models of Alzheimer's disease (AD) and AD-related dementias (ADRD), the limited translatability to human disease raises concerns about their overall utility. What factors contribute to this limitation? Is AD inherently too complex to be accurately modeled in nonhumans? Is the divergence between rodent brains and the human brain so pronounced that rodents are unsuitable as model organisms for AD? Or is it plausible that the commonly used rodent models don't capture the genuine pathogenic mechanisms underlying these diseases? This editorial discusses the challenges associated with transgenic models of AD and ADRD and offers some alternative approaches.
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Affiliation(s)
- Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, RutgersThe State University of New JerseyNewarkNJUSA
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Yesiltepe M, Yin T, D’Adamio L. Beyond amyloid: altered gene function in neurodegenerative diseases. Aging (Albany NY) 2023; 15:9235-9237. [PMID: 37733660 PMCID: PMC10564419 DOI: 10.18632/aging.204717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 05/02/2023] [Indexed: 09/23/2023]
Affiliation(s)
- Metin Yesiltepe
- Department of Pharmacology, Physiology and Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer’s Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Tao Yin
- Department of Pharmacology, Physiology and Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer’s Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Luciano D’Adamio
- Department of Pharmacology, Physiology and Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer’s Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
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Tambini MD, Yin T, Yesiltepe M, Breuillaud L, Zehntner SP, d'Abramo C, Giliberto L, D'Adamio L. Aβ43 levels determine the onset of pathological amyloid deposition. J Biol Chem 2023; 299:104868. [PMID: 37257821 PMCID: PMC10404620 DOI: 10.1016/j.jbc.2023.104868] [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: 02/02/2023] [Revised: 04/18/2023] [Accepted: 05/22/2023] [Indexed: 06/02/2023] Open
Abstract
About 2% of Alzheimer's disease (AD) cases have early onset (FAD) and are caused by mutations in either Presenilins (PSEN1/2) or amyloid-β precursor protein (APP). PSEN1/2 catalyze production of Aβ peptides of different length from APP. Aβ peptides are the major components of amyloid plaques, a pathological lesion that characterizes AD. Analysis of mechanisms by which PSEN1/2 and APP mutations affect Aβ peptide compositions lead to the implication of the absolute or relative increase in Aβ42 in amyloid-β plaques formation. Here, to elucidate the formation of pathogenic Aβ cocktails leading to amyloid pathology, we utilized FAD rat knock-in models carrying the Swedish APP (Apps allele) and the PSEN1 L435F (Psen1LF allele) mutations. To accommodate the differences in the pathogenicity of rodent and human Aβ, these rat models are genetically engineered to express human Aβ species as both the Swedish mutant allele and the WT rat allele (called Apph) have been humanized in the Aβ-coding region. Analysis of the eight possible FAD mutant permutations indicates that the CNS levels of Aβ43, rather than absolute or relative increases in Aβ42, determine the onset of pathological amyloid deposition in FAD knock-in rats. Notably, Aβ43 was found in amyloid plaques in late onset AD and mild cognitive impairment cases, suggesting that the mechanisms initiating amyloid pathology in FAD knock-in rat reflect disease mechanisms driving amyloid pathology in late onset AD. This study helps clarifying the molecular determinants initiating amyloid pathology and supports therapeutic interventions targeting Aβ43 in AD.
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Affiliation(s)
- Marc D Tambini
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Tao Yin
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Metin Yesiltepe
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | | | | | - Cristina d'Abramo
- Litwin-Zucker Center for the Study of Alzheimer's Disease and Memory Disorders, Feinstein Institutes for Medical Research, Institute of Molecular Medicine, Northwell Health System, Manhasset, New York, USA
| | - Luca Giliberto
- Litwin-Zucker Center for the Study of Alzheimer's Disease and Memory Disorders, Feinstein Institutes for Medical Research, Institute of Molecular Medicine, Northwell Health System, Manhasset, New York, USA; Institute of Neurology and Neurosurgery, Northwell Health System, Manhasset, New York, USA
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA.
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Yesiltepe M, Yin T, Tambini MD, Breuillaud L, Zehntner SP, D’Adamio L. Late-long-term potentiation magnitude, but not Aβ levels and amyloid pathology, is associated with behavioral performance in a rat knock-in model of Alzheimer disease. Front Aging Neurosci 2022; 14:1040576. [PMID: 36438008 PMCID: PMC9691854 DOI: 10.3389/fnagi.2022.1040576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 10/31/2022] [Indexed: 09/23/2023] Open
Abstract
Cleavage of Amyloid precursor protein by β- and γ-secretases lead to Aβ formation. The widely accepted pathogenic model states that these mutations cause AD via an increase in Aβ formation and accumulation of Aβ in Amyloid plaques. APP mutations cause early onset familial forms of Alzheimer's disease (FAD) in humans. We generated App-Swedish (Apps ) knock-in rats, which carry a pathogenic APP mutation in the endogenous rat App gene. This mutation increases β-secretase processing of APP leading to both augmented Aβ production and facilitation of glutamate release in Apps/s rats, via a β-secretase and APP-dependent glutamate release mechanism. Here, we studied 11 to 14-month-old male and female Apps/s rats. To determine whether the Swedish App mutation leads to behavioral deficits, Apps/s knock-in rats were subjected to behavioral analysis using the IntelliCage platform, an automated behavioral testing system. This system allows behavioral assessment in socially housed animals reflecting a more natural, less stress-inducing environment and eliminates experimenter error and bias while increasing precision of measurements. Surprisingly, a spatial discrimination and flexibility task that can reveal deficits in higher order brain function showed that Apps/s females, but not Apps/s male rats, performed significantly worse than same sex controls. Moreover, female control rats performed significantly better than control and Apps/s male rats. The Swedish mutation causes a significant increase in Aβ production in 14-month-old animals of both sexes. Yet, male and female Apps/s rats showed no evidence of AD-related amyloid pathology. Finally, Apps/s rats did not show signs of significant neuroinflammation. Given that the APP Swedish mutation causes alterations in glutamate release, we analyzed Long-term potentiation (LTP), a long-lasting form of synaptic plasticity that is a cellular basis for learning and memory. Strikingly, LTP was significantly increased in Apps/s control females compared to both Apps/s sexes and control males. In conclusion, this study shows that behavioral performances are sex and App-genotype dependent. In addition, they are associated with LTP values and not Aβ or AD-related pathology. These data, and the failures of anti-Aβ therapies in humans, suggest that alternative pathways, such as those leading to LTP dysfunction, should be targeted for disease-modifying AD therapy.
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Affiliation(s)
- Metin Yesiltepe
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer’s Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | - Tao Yin
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer’s Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | - Marc D. Tambini
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer’s Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | | | | | - Luciano D’Adamio
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer’s Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, NJ, United States
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Shir D, Day GS. Deciphering the contributions of neuroinflammation to neurodegeneration: lessons from antibody-mediated encephalitis and coronavirus disease 2019. Curr Opin Neurol 2022; 35:212-219. [PMID: 35102125 PMCID: PMC8896289 DOI: 10.1097/wco.0000000000001033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
PURPOSE OF REVIEW Does neuroinflammation promote neurodegeneration? Does neurodegeneration promote neuroinflammation? Or, is the answer to both questions, yes? These questions have proven challenging to answer in patients with typical age-related neurodegenerative diseases in whom the onset of neuroinflammation and neurodegeneration are largely unknown. Patients recovering from diseases associated with abrupt-onset neuroinflammation, including rare forms of antibody-mediated encephalitis (AME) and common complications of novel coronavirus disease 2019 (COVID-19), provide a unique opportunity to untangle the relationship between neuroinflammation and neurodegeneration. This review explores the lessons learned from patients with AME and COVID-19. RECENT FINDINGS Persistent cognitive impairment is increasingly recognized in patients recovering from AME or COVID-19, yet the drivers of impairment remain largely unknown. Clinical observations, neuroimaging and biofluid biomarkers, and pathological studies imply a link between the severity of acute neuroinflammation, subsequent neurodegeneration, and disease-associated morbidity. SUMMARY Data from patients with AME and COVID-19 inform key hypotheses that may be evaluated through future studies incorporating longitudinal biomarkers of neuroinflammation and neurodegeneration in larger numbers of recovering patients. The results of these studies may inform the contributors to cognitive impairment in patients with AME and COVID-19, with potential diagnostic and therapeutic applications in patients with age-related neurodegenerative diseases.
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Affiliation(s)
- Dror Shir
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Gregory S. Day
- Department of Neurology, Mayo Clinic, Jacksonville, Florida, USA
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