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Rentsch P, Ganesan K, Langdon A, Konen LM, Vissel B. Toward the development of a sporadic model of Alzheimer's disease: comparing pathologies between humanized APP and the familial J20 mouse models. Front Aging Neurosci 2024; 16:1421900. [PMID: 39040546 PMCID: PMC11260812 DOI: 10.3389/fnagi.2024.1421900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 06/03/2024] [Indexed: 07/24/2024] Open
Abstract
Background Finding successful therapies for individuals with Alzheimer's disease (AD) remains an ongoing challenge. One contributing factor is that the mouse models commonly used in preclinical research primarily mimic the familial form of AD, whereas the vast majority of human cases are sporadic. Accordingly, for a sporadic mouse model of AD, incorporating the multifactorial aspects of the disease is of utmost importance. Methods In the current study, we exposed humanized Aβ knock-in mice (hAβ-KI) to weekly low-dose lipopolysaccharide (LPS) injections until 24 weeks of age and compared the development of AD pathologies to the familial AD mouse model known as the J20 mice. Results At the early time point of 24 weeks, hAβ-KI mice and J20 mice exhibited spatial memory impairments in the Barnes maze. Strikingly, both hAβ-KI mice and J20 mice showed significant loss of dendritic spines when compared to WT controls, despite the absence of Aβ plaques in hAβ-KI mice at 24 weeks of age. Glial cell numbers remained unchanged in hAβ-KI mice compared to WT, and LPS exposure in hAβ-KI mice did not result in memory deficits and failed to exacerbate any other examined AD pathology. Conclusion The study highlights the potential of hAβ-KI mice as a model for sporadic AD, demonstrating early cognitive deficits and synaptic alterations despite no evidence of Aβ plaque formation. These findings underscore the importance of considering multifactorial influences in sporadic AD pathogenesis and the need for innovative models to advance our understanding and treatment strategies for this complex disease.
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Affiliation(s)
- Peggy Rentsch
- Centre for Neuroscience and Regenerative Medicine, St. Vincent's Centre for Applied Medical Research, St Vincent's Hospital, Sydney, NSW, Australia
- UNSW St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Kiruthika Ganesan
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Alexander Langdon
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Lyndsey M. Konen
- Centre for Neuroscience and Regenerative Medicine, St. Vincent's Centre for Applied Medical Research, St Vincent's Hospital, Sydney, NSW, Australia
| | - Bryce Vissel
- Centre for Neuroscience and Regenerative Medicine, St. Vincent's Centre for Applied Medical Research, St Vincent's Hospital, Sydney, NSW, Australia
- UNSW St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
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2
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George M, Reddy AP, Reddy PH, Kshirsagar S. Unraveling the NRF2 confusion: Distinguishing nuclear respiratory factor 2 from nuclear erythroid factor 2. Ageing Res Rev 2024; 98:102353. [PMID: 38815934 PMCID: PMC11176867 DOI: 10.1016/j.arr.2024.102353] [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: 05/23/2024] [Revised: 05/26/2024] [Accepted: 05/27/2024] [Indexed: 06/01/2024]
Abstract
In recent years, the acronym NRF2 has garnered significant attention in scientific discourse. However, this attention has occasionally led to confusion due to the existence of two distinct proteins sharing the same acronym: Nuclear Respiratory Factor 2 (NRF2), also known as GA-binding protein transcription factor subunit alpha (GABPA), and Nuclear Factor Erythroid 2-related Factor 2 (NFE2L2 or NRF2). This confusion has been highlighted in various scientific forums, including PubPeer and anonymous reader comments, where the confusion between the two proteins has been expressed. In this article, we aim to elucidate the disparities between these two proteins. Both are transcription factors that play pivotal roles in cellular homeostasis and response to stress, with some overlapping functional aspects. Nuclear Factor Erythroid 2-related Factor 2 (NFE2L2) is a key regulator of the antioxidant response element (ARE) pathway. It functions by binding to antioxidant response elements in the promoters of target genes, thereby orchestrating the expression of various cytoprotective enzymes and proteins involved in detoxification, redox balance, and cellular defense against oxidative stress. Conversely, Nuclear Respiratory Factor 2 (GABPA) is primarily associated with the regulation of mitochondrial biogenesis, in relation to PGC1α, and maintaining cellular energy metabolism. It is important to recognize and differentiate between these two proteins to avoid misconceptions and misinterpretations in scientific literature and discussions. Our laboratories (Arubala P Reddy and P. Hemachandra Reddy) focued on Nuclear Respiratory Factor 2 (NRF2), but not on Nuclear Factor Erythroid 2-related Factor 2 (NFE2L2). We hope that the facts, figures, and discussions presented in this article will clarify the current controversy regarding the sizes, structural features, and functional aspects of these proteins.
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Affiliation(s)
- Mathew George
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Arubala P Reddy
- Nutritional Sciences Department, College Human Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - P Hemachandra Reddy
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Nutritional Sciences Department, College Human Sciences, Texas Tech University, Lubbock, TX 79409, USA; Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA 5. Department of Public Health, Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Speech, Language, and Hearing Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
| | - Sudhir Kshirsagar
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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3
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Rivera J, Sharma B, Torres MM, Kumar S. Factors affecting the GABAergic synapse function in Alzheimer's disease: Focus on microRNAs. Ageing Res Rev 2023; 92:102123. [PMID: 37967653 DOI: 10.1016/j.arr.2023.102123] [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: 09/01/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/17/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurological disease characterized by the loss of cognitive function, confusion, and memory deficit. Accumulation of abnormal proteins, amyloid beta (Aß), and phosphorylated Tau (p-tau) forms plaques and tangles that deteriorate synapse function, resulting in neurodegeneration and cognitive decline in AD. The human brain is composed of different types of neurons and/or synapses that are functionally defective in AD. The GABAergic synapse, the most abundant inhibitory neuron in the human brain was found to be dysfunctional in AD and contributes to disrupting neurological function. This study explored the types of GABA receptors associated with neurological dysfunction and various biological and environmental factors that cause GABAergic neuron dysfunction in AD, such as Aβ, p-tau, aging, sex, astrocytes, microglia, APOE, mental disorder, diet, physical activity, and sleep. Furthermore, we explored the role of microRNAs (miRNAs) in the regulation of GABAergic synapse function in neurological disorders and AD states. We also discuss the molecular mechanisms underlying GABAergic synapse dysfunction with a focus on miR-27b, miR-30a, miR-190a/b, miR-33, miR-51, miR-129-5p, miR-376-3p, miR-376c, miR-30b and miR-502-3p. The purpose of our article is to highlight the recent research on miRNAs affecting the regulation of GABAergic synapse function and factors that contribute to the progression of AD.
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Affiliation(s)
- Jazmin Rivera
- Center of Emphasis in Neuroscience, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA
| | - Bhupender Sharma
- Center of Emphasis in Neuroscience, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA
| | - Melissa M Torres
- Center of Emphasis in Neuroscience, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA
| | - Subodh Kumar
- Center of Emphasis in Neuroscience, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA; L. Frederick Francis Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, El Paso, TX, USA.
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4
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Jia K, Tian J, Wang T, Guo L, Xuan Z, Swerdlow RH, Du H. Mitochondria-sequestered Aβ renders synaptic mitochondria vulnerable in the elderly with a risk of Alzheimer disease. JCI Insight 2023; 8:e174290. [PMID: 37991017 PMCID: PMC10721326 DOI: 10.1172/jci.insight.174290] [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: 08/02/2023] [Accepted: 10/13/2023] [Indexed: 11/23/2023] Open
Abstract
Mitochondria are critical for neurophysiology, and mitochondrial dysfunction constitutes a characteristic pathology in both brain aging and Alzheimer disease (AD). Whether mitochondrial deficiency in brain aging and AD is mechanistically linked, however, remains controversial. We report a correlation between intrasynaptosomal amyloid β 42 (Aβ42) and synaptic mitochondrial bioenergetics inefficiency in both aging and amnestic mild cognitive impairment, a transitional stage between normal aging and AD. Experiments using a mouse model expressing nonmutant humanized Aβ (humanized Aβ-knockin [hAβ-KI] mice) confirmed the association of increased intramitochondrial sequestration of Aβ42 with exacerbated synaptic mitochondrial dysfunction in an aging factor- and AD risk-bearing context. Also, in comparison with global cerebral Aβ, intramitochondrial Aβ was relatively preserved from activated microglial phagocytosis in aged hAβ-KI mice. The most parsimonious interpretation of our results is that aging-related mitochondrial Aβ sequestration renders synaptic mitochondrial dysfunction in the transitional stage between normal aging and AD. Mitochondrial dysfunction in both brain aging and the prodromal stage of AD may follow a continuous transition in response to escalated intraneuronal, especially intramitochondrial Aβ, accumulation. Moreover, our findings further implicate a pivotal role of mitochondria in harboring early amyloidosis during the conversion from normal to pathological aging.
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Affiliation(s)
- Kun Jia
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, USA
| | - Jing Tian
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, USA
| | - Tienju Wang
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, USA
| | - Lan Guo
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, USA
| | - Zhenyu Xuan
- Department of Biological Sciences, Center for Systems Biology, University of Texas at Dallas, Richardson, Texas, USA
| | - Russell H. Swerdlow
- Alzheimer’s Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Heng Du
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, USA
- Alzheimer’s Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA
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Reddy PH, Kshirsagar S, Bose C, Pradeepkiran JA, Hindle A, Singh SP, Reddy AP. Rlip overexpression reduces oxidative stress and mitochondrial dysfunction in Alzheimer's disease: Mechanistic insights. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166759. [PMID: 37225106 DOI: 10.1016/j.bbadis.2023.166759] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 05/26/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease that affects a large proportion of the aging population. RalBP1 (Rlip) is a stress-activated protein that plays a crucial role in oxidative stress and mitochondrial dysfunction in aging and neurodegenerative diseases but its precise role in the progression of AD is unclear. The purpose of our study is to understand the role of Rlip in the progression and pathogenesis of AD in mutant APP/amyloid beta (Aβ)-expressed mouse primary hippocampal (HT22) hippocampal neurons. In the current study, we used HT22 neurons that express mAPP, transfected with Rlip-cDNA and/or RNA silenced, and studied cell survival, mitochondrial respiration, mitochondrial function, immunoblotting & immunofluorescence analysis of synaptic and mitophagy protein's and colocalization of Rlip and mutant APP/Aβ proteins and mitochondrial length and number. We also assessed Rlip levels in autopsy brains from AD patients and control subjects. We found cell survival was decreased in mAPP-HT22 cells and RNA-silenced HT22 cells. However, cell survival was increased in Rlip-overexpressed mAPP-HT22 cells. Oxygen consumption rate (OCR) was decreased in mAPP-HT22 cells and RNA-silenced Rlip-HT22 cells. OCR was increased in Rlip-overexpressed in mAPP-HT22 cells. Mitochondrial function was defective in mAPP-HT22 cells and RNA silenced Rlip in HT22 cells, however, it was rescued in Rlip overexpressed mAPP-HT22 cells. Synaptic and mitophagy proteins were decreased in mAPP-HT22 cells, further reducing RNA-silenced Rlip-HT22 cells. However, these were increased in mAPP+Rlip-HT22 cells. Colocalization analysis revealed Rlip is colocalized with mAPP/Aβ. An increased number of mitochondria and decreased mitochondrial length were found in mAPP-HT22 cells. These were rescued in Rlip overexpressed mAPP-HT22 cells. Reduced Rlip levels were found in autopsy brains from AD patients. These observations strongly suggest that Rlip deficiency causes oxidative stress/mitochondrial dysfunction and Rlip overexpression reduced these defects.
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Affiliation(s)
- P Hemachandra Reddy
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Nutritional Sciences Department, College of Human Sciences, Texas Tech University, 1301 Akron Ave, Lubbock, TX 79409, USA; Neurology, Departments of School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Public Health Department of Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Speech, Language and Hearing Sciences, School Health Professions, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
| | - Sudhir Kshirsagar
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Chhanda Bose
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | | | - Ashly Hindle
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Sharda P Singh
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Arubala P Reddy
- Nutritional Sciences Department, College of Human Sciences, Texas Tech University, 1301 Akron Ave, Lubbock, TX 79409, USA
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Manna PR, Kshirsagar S, Pradeepkiran JA, Rawat P, Kumar S, Reddy AP, Reddy PH. Protective function of StAR in amyloid-β accumulated hippocampal neurotoxicity and neurosteroidogenesis: Mechanistic insights into Alzheimer's disease. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166738. [PMID: 37142132 DOI: 10.1016/j.bbadis.2023.166738] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 04/25/2023] [Accepted: 04/27/2023] [Indexed: 05/06/2023]
Abstract
The steroidogenic acute regulatory (StAR) protein principally mediates steroid hormone biosynthesis by governing the transport of intramitochondrial cholesterol. Neurosteroids progressively decrease during aging, the key risk factor for Alzheimer's disease (AD), which is triggered by brain-region specific accumulation of amyloid beta (Aβ) precursor protein (APP), a key pathological factor. We demonstrate that hippocampal neuronal cells overexpressing wild-type (WtAPP) and mutant APP (mAPP) plasmids, conditions mimetic to AD, resulted in decreases in StAR mRNA, free cholesterol, and pregnenolone levels. The magnitude of suppression of the steroidogenic response was more pronounced with mAPP than that of WtAPP. While mAPP-waned assorted anomalies correlate to AD pathology, deterioration of APP/Aβ laden StAR expression and neurosteroid biosynthesis was enhanced by retinoid signaling. An abundance of mitochondrially targeted StAR expression partially restored APP/Aβ accumulated diverse neurodegenerative vulnerabilities. Immunofluorescence analyses revealed that overexpression of StAR diminishes mAPP provoked Aβ aggregation. Co-expression of StAR and mAPP in hippocampal neurons substantially reversed the declines in mAPP mediated cell survival, mitochondrial oxygen consumption rate, and ATP production. Concurrently, induction of mAPP induced Aβ loading showed an increase in cholesterol esters, but decrease in free cholesterol, concomitant with pregnenolone biosynthesis, events that were inversely regulated by StAR. Moreover, retinoid signaling was found to augment cholesterol content for facilitating neurosteroid biosynthesis in an AD mimetic condition. These findings provide novel insights into the molecular events by which StAR acts to protect mAPP-induced hippocampal neurotoxicity, mitochondrial dysfunction, and neurosteroidogenesis, and these measures are fundamental for ameliorating and/or delaying dementia in individuals with AD.
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Affiliation(s)
- Pulak R Manna
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
| | - Sudhir Kshirsagar
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | | | - Priyanka Rawat
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Subodh Kumar
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center of Emphasis in Neuroscience, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Arubala P Reddy
- Nutritional Sciences Department, College of Human Sciences, Texas Tech University, 1301 Akron Ave, Lubbock, TX 79409, USA
| | - P Hemachandra Reddy
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Nutritional Sciences Department, College of Human Sciences, Texas Tech University, 1301 Akron Ave, Lubbock, TX 79409, USA; Neurology, Departments of School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Public Health Department of Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Speech, Language and Hearing Sciences, School Health Professions, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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Wojtunik-Kulesza K, Rudkowska M, Orzeł-Sajdłowska A. Aducanumab-Hope or Disappointment for Alzheimer's Disease. Int J Mol Sci 2023; 24:ijms24054367. [PMID: 36901797 PMCID: PMC10002282 DOI: 10.3390/ijms24054367] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
In June 2021, the world was informed about a new drug for Alzheimer's disease approved by the FDA. Aducanumab (BIIB037, ADU), being a monoclonal antibody IgG1, is the newest AD treatment. The activity of the drug is targeted towards amyloid β, which is considered one of the main causes of Alzheimer's disease. Clinical trials have revealed time- and dose-dependent activity towards Aβ reduction, as well as cognition improvement. Biogen, the company responsible for conducting research and introducing the drug to the market, presents the drug as a solution to cognitive impairment, but its limitations, costs, and side effects are controversial. The framework of the paper focuses on the mechanism of aducanumab's action along with the positive and negative sides of the therapy. The review presents the basis of the amyloid hypothesis that is the cornerstone of therapy, as well as the latest information about aducanumab, its mechanism of action, and the possibility of the use of the drug.
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Affiliation(s)
- Karolina Wojtunik-Kulesza
- Department of Inorganic Chemistry, Medical University of Lublin, 20-059 Lublin, Poland
- Correspondence:
| | - Monika Rudkowska
- Independent Laboratory of Behavioral Studies, Medical University of Lublin, Jaczewskiego 4, 20-090 Lublin, Poland
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Sharma N, Banerjee R, Davis RL. Early Mitochondrial Defects in the 5xFAD Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2023; 91:1323-1338. [PMID: 36617782 DOI: 10.3233/jad-220884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Mitochondrial (MT) dysfunction is a hallmark of Alzheimer's disease (AD). Amyloid-β protein precursor and amyloid-β peptides localize to MT and lead to MT dysfunction in familial forms of AD. This dysfunction may trigger subsequent types of pathology. OBJECTIVE To identify the MT phenotypes that occur early in order to help understand the cascade of AD pathophysiology. METHODS The 5xFAD mouse model was used to explore the time course of MT pathologies in both sexes. Protein biomarkers for MT dynamics were measured biochemically and MT function was measured using oxygen consumption and ATP assays. RESULTS We discovered progressive alterations in mitochondrial dynamics (biogenesis, fission, fusion, and mitophagy) and function (O2 consumption, ATP generation, and Ca2+ import) in the hippocampus of 5xFAD mice in both sexes as early as 2 months of age. Thus, mitochondrial dynamics and function become altered at young ages, consistent with an early role for mitochondria in the AD pathological cascade. CONCLUSION Our study offers the baseline information required to understand the hierarchical relationship between the multiple pathologies that develop in this mouse model and provides early biomarkers for MT dysfunction. This will aid in dissecting the temporal cascade of pathologies, understanding sex-specific differences, and in testing the efficacy of putative mitochondrial therapeutics.
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Affiliation(s)
- Neelam Sharma
- Department of Neuroscience, University of Florida Scripps Biomedical Research Institute, Jupiter, FL, USA
| | - Rupkatha Banerjee
- Department of Neuroscience, University of Florida Scripps Biomedical Research Institute, Jupiter, FL, USA
| | - Ronald L Davis
- Department of Neuroscience, University of Florida Scripps Biomedical Research Institute, Jupiter, FL, USA
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Kshirsagar S, Alvir RV, Pradeepkiran JA, Hindle A, Vijayan M, Ramasubramaniam B, Kumar S, Reddy AP, Reddy PH. A Combination Therapy of Urolithin A+EGCG Has Stronger Protective Effects Than Single Drug Urolithin A in a Humanized Amyloid Beta Knockin Mice for Late-Onset Alzheimer’s Disease. Cells 2022; 11:cells11172660. [PMID: 36078067 PMCID: PMC9454743 DOI: 10.3390/cells11172660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 12/03/2022] Open
Abstract
In the current study, for the first time, we study mitophagy enhancer urolithin A and a combination of urolithin A+green tea extract EGCG against human Aβ peptide-induced mitochondrial and synaptic, dendritic, inflammatory toxicities and behavioral changes in humanized homozygous amyloid beta knockin (hAbKI) mice of late-onset Alzheimer’s disease (AD). Our findings reveal significantly increased positive effects of urolithin A and a combination treatment of urolithin A+EGCG in hAbKI mice for phenotypic behavioral changes including motor coordination, locomotion/exploratory activity, spatial learning and working memory. mRNA and protein levels of mitochondrial fusion, synaptic, mitophagy and autophagy genes were upregulated, and mitochondrial fission genes are downregulated in urolithin A and combine treatment in hAbKI mice; however, the effect is stronger in combined treatment. Immunofluorescence analysis of hippocampal brain sections shows similar findings of mRNA and protein levels. Mitochondrial dysfunction is significantly reduced in both treatment groups, but a stronger reduction is observed in combined treatment. Dendritic spines and lengths are significantly increased in both treatment groups, but the effect is stronger in combined treatment. The fragmented number of mitochondria is reduced, and mitochondrial length is increased, and mitophagosomal formations are increased in both the groups, but the effect is stronger in the combined treatment. The levels of amyloid beta (Aβ) 40 and Aβ42 are reduced in both treatments, however, the reduction is higher for combined treatment. These observations suggest that urolithin A is protective against human Aβ peptide-induced toxicities; however, combined treatment of urolithin A+EGCG is effective and stronger, indicating that combined therapy is promising to treat late-onset AD patients.
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Affiliation(s)
- Sudhir Kshirsagar
- Department of Internal Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Rainier Vladlen Alvir
- Department of Internal Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Jangampalli Adi Pradeepkiran
- Department of Internal Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Ashly Hindle
- Department of Internal Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Murali Vijayan
- Department of Internal Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Bhagavathi Ramasubramaniam
- Department of Internal Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Subodh Kumar
- Department of Internal Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
- Center of Emphasis in Neuroscience, Department of Molecular and Translational Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Arubala P. Reddy
- Nutritional Sciences Department, College of Human Sciences, Texas Tech University, 1301 Akron Ave, Lubbock, TX 79409, USA
| | - P. Hemachandra Reddy
- Department of Internal Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
- Nutritional Sciences Department, College of Human Sciences, Texas Tech University, 1301 Akron Ave, Lubbock, TX 79409, USA
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Department of Public Health, Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Department of Speech, Language, and Hearing Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Correspondence: ; Tel.: +1-806-743-3194
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10
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Pradeepkiran JA, Hindle A, Kshirsagar S, Reddy PH. Are mitophagy enhancers therapeutic targets for Alzheimer's disease? Biomed Pharmacother 2022; 149:112918. [PMID: 35585708 PMCID: PMC9148418 DOI: 10.1016/j.biopha.2022.112918] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/18/2022] [Accepted: 03/30/2022] [Indexed: 01/09/2023] Open
Abstract
Healthy mitochondria are essential for functional bioenergetics, calcium signaling, and balanced redox homeostasis. Dysfunctional mitochondria are a central aspect of aging and neurodegenerative diseases such as Alzheimer's disease (AD). The formation and accumulation of amyloid beta (Aβ) and hyperphosphorylated tau (P-tau) play large roles in the cellular changes seen in AD, including mitochondrial dysfunction, synaptic damage, neuronal loss, and defective mitophagy. Mitophagy is the cellular process whereby damaged mitochondria are selectively removed, and it plays an important role in mitochondrial quality control. Dysfunctional mitochondria are associated with increased reactive oxygen species and increased levels of Aβ, P-tau and Drp1, which together trigger mitophagy and autophagy. Impaired mitophagy causes the progressive accumulation of defective organelles and damaged mitochondria, and it has been hypothesized that the restoration of mitophagy may offer therapeutic benefits to AD patients. This review highlights the challenges of pharmacologically inducing mitophagy through two different signaling cascades: 1) The PINK1/parkin-dependent pathway and 2) the PINK1/parkin-independent pathway, with an emphasis on abnormal mitochondrial interactions with Aβ and P-Tau, which alter mitophagy in an age-dependent manner. This article also summarizes recent studies on the effects of mitophagy enhancers, including urolithin A, NAD+, actinonin, and tomatidine, on mutant APP/Aβ and mutant Tau. Findings from our lab have revealed that mitophagy enhancers can suppress APP/Aβ-induced and mutant Tau-induced mitochondrial and synaptic dysfunctions in mouse and cell line models of AD. Finally, we discuss the mechanisms underlying the beneficial health effects of mitophagy enhancers like urolithin A, NAD+, resveratrol and spermidine in AD.
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Affiliation(s)
| | - Ashly Hindle
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Sudhir Kshirsagar
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - P Hemachandra Reddy
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Public Health, Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Speech, Language, and Hearing Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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