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Area-Gomez E, Schon EA. Towards a Unitary Hypothesis of Alzheimer's Disease Pathogenesis. J Alzheimers Dis 2024; 98:1243-1275. [PMID: 38578892 DOI: 10.3233/jad-231318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
The "amyloid cascade" hypothesis of Alzheimer's disease (AD) pathogenesis invokes the accumulation in the brain of plaques (containing the amyloid-β protein precursor [AβPP] cleavage product amyloid-β [Aβ]) and tangles (containing hyperphosphorylated tau) as drivers of pathogenesis. However, the poor track record of clinical trials based on this hypothesis suggests that the accumulation of these peptides is not the only cause of AD. Here, an alternative hypothesis is proposed in which the AβPP cleavage product C99, not Aβ, is the main culprit, via its role as a regulator of cholesterol metabolism. C99, which is a cholesterol sensor, promotes the formation of mitochondria-associated endoplasmic reticulum (ER) membranes (MAM), a cholesterol-rich lipid raft-like subdomain of the ER that communicates, both physically and biochemically, with mitochondria. We propose that in early-onset AD (EOAD), MAM-localized C99 is elevated above normal levels, resulting in increased transport of cholesterol from the plasma membrane to membranes of intracellular organelles, such as ER/endosomes, thereby upregulating MAM function and driving pathology. By the same token, late-onset AD (LOAD) is triggered by any genetic variant that increases the accumulation of intracellular cholesterol that, in turn, boosts the levels of C99 and again upregulates MAM function. Thus, the functional cause of AD is upregulated MAM function that, in turn, causes the hallmark disease phenotypes, including the plaques and tangles. Accordingly, the MAM hypothesis invokes two key interrelated elements, C99 and cholesterol, that converge at the MAM to drive AD pathogenesis. From this perspective, AD is, at bottom, a lipid disorder.
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Affiliation(s)
- Estela Area-Gomez
- Department of Neurology, Columbia University, New York, NY, USA
- Centro de Investigaciones Biológicas "Margarita Salas", Spanish National Research Council, Madrid, Spain
| | - Eric A Schon
- Department of Neurology, Columbia University, New York, NY, USA
- Department of Genetics and Development>, Columbia University, New York, NY, USA
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Jiang RQ, Li QQ, Sheng R. Mitochondria associated ER membrane and cerebral ischemia: molecular mechanisms and therapeutic strategies. Pharmacol Res 2023; 191:106761. [PMID: 37028777 DOI: 10.1016/j.phrs.2023.106761] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 04/04/2023] [Indexed: 04/09/2023]
Abstract
Endoplasmic reticulum (ER) and mitochondria are two important organelles that are highly dynamic in mammalian cells. The physical connection between them is mitochondria associated ER membranes (MAM). In recent years, studies on endoplasmic reticulum and mitochondria have shifted from independent division to association and comparison, especially MAM has gradually become a research hotspot. MAM connects the two organelles, not only to maintain their independent structure and function, but also to promote metabolism and signal transduction between them. This paper reviews the morphological structure and protein localization of MAM, and briefly analyzes the functions of MAM in regulating Ca2+ transport, lipid synthesis, mitochondrial fusion and fission, endoplasmic reticulum stress and oxidative stress, autophagy and inflammation. Since ER stress and mitochondrial dysfunction are important pathological events in neurological diseases including ischemic stroke, MAM is likely to play an important role in cerebral ischemia by regulating the signaling of the two organelles and the crosstalk of the two pathological events.
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Affiliation(s)
- Rui-Qi Jiang
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, China
| | - Qi-Qi Li
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, China
| | - Rui Sheng
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, China.
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Li Z, Cao Y, Pei H, Ma L, Yang Y, Li H. The contribution of mitochondria-associated endoplasmic reticulum membranes (MAMs) dysfunction in Alzheimer's disease and the potential countermeasure. Front Neurosci 2023; 17:1158204. [PMID: 36960176 PMCID: PMC10027904 DOI: 10.3389/fnins.2023.1158204] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 02/23/2023] [Indexed: 03/09/2023] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease. There are many studies targeting extracellular deposits of amyloid β-peptide (Aβ) and intracellular neurofibrillary tangles (NFTs), however, there are no effective treatments to halt the progression. Mitochondria-associated endoplasmic reticulum membranes (MAMs) have long been found to be associated with various pathogenesis hypotheses of AD, such as Aβ deposition, mitochondrial dysfunction, and calcium homeostasis. However, there is a lack of literature summarizing recent advances in the mechanism and treatment studies. Accordingly, this article reviews the latest research involving the roles of MAM structure and tethering proteins in the pathogenesis of AD and summarizes potential strategies targeting MAMs to dissect treatment perspectives for AD.
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Affiliation(s)
- Zehui Li
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yu Cao
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hui Pei
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Lina Ma
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yang Yang
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Yang Yang,
| | - Hao Li
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Hao Li,
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Wendler A, Wehling M. Many or too many progesterone membrane receptors? Clinical implications. Trends Endocrinol Metab 2022; 33:850-868. [PMID: 36384863 DOI: 10.1016/j.tem.2022.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/07/2022] [Accepted: 10/12/2022] [Indexed: 11/15/2022]
Abstract
Several receptors for nongenomically initiated actions of progesterone (P4) exist, namely membrane-associated P4 receptors (MAPRs), membrane progestin receptors (mPRs), receptors for neurosteroids [GABAA receptor (GABAAR), NMDA receptor, sigma-1 and -2 receptors (S1R/S2R)], the classical genomic P4 receptor (PGR), and α/β hydrolase domain-containing protein 2 (ABHD2). Two drugs related to this field have been approved: brexanolone (Zulresso™) for the treatment of postpartum depression, and ganaxolone (Ztalmy™) for the treatment of CDKL5 deficiency disorder. Both are derivatives of P4 and target the GABAAR. Several other indications are in clinical testing. CT1812 (Elayta™) is also being tested for the treatment of Alzheimer's disease (AD) in Phase 2 clinical trials, targeting the P4 receptor membrane component 1 (PGRMC1)/S2R complex. In this Review, we highlight emerging knowledge on the mechanisms of nongenomically initiated actions of P4 and its derivatives.
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Affiliation(s)
- Alexandra Wendler
- Clinical Pharmacology Mannheim, Faculty of Medicine Mannheim, Ruprecht-Karls-University of Heidelberg, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany
| | - Martin Wehling
- Clinical Pharmacology Mannheim, Faculty of Medicine Mannheim, Ruprecht-Karls-University of Heidelberg, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany.
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Cai Y, Chai Y, Fu Y, Wang Y, Zhang Y, Zhang X, Zhu L, Miao M, Yan T. Salidroside Ameliorates Alzheimer's Disease by Targeting NLRP3 Inflammasome-Mediated Pyroptosis. Front Aging Neurosci 2022; 13:809433. [PMID: 35126093 PMCID: PMC8814655 DOI: 10.3389/fnagi.2021.809433] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/13/2021] [Indexed: 12/20/2022] Open
Abstract
Amyloid β-protein (Aβ) is reported to activate NLRP3 inflammasomes and drive pyroptosis, which is subsequently involved in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD). To date, the pathogenesis of AD is unfortunately insufficiently elucidated. Therefore, this study was conducted to explore whether Salidroside (Sal) treatment could benefit AD by improving pyroptosis. Firstly, two animal models of AD, induced, respectively, by Aβ1-42 and D-galactose (D-gal)/AlCl3, have been created to assist our appreciation of AD pathophysiology. We then confirmed that pyroptosis is related to the pathogenesis of AD, and Sal can slow the progression of AD by inhibiting pyroptosis. Subsequently, we established the D-gal and Nigericin-induced PC12 cells injury model in vitro to verify Sal blocks pyroptosis mainly by targeting the NLRP3 inflammasome. For in vivo studies, we observed that Aβ accumulation, Tau hyperphosphorylation, neurons of hippocampal damage, and cognitive dysfunction in AD mice, caused by bilateral injection of Aβ1-42 into the hippocampus and treatments with D-gal combine AlCl3. Besides, accumulated Aβ promotes NLRP3 inflammasome activation, which leads to the activation and release of a pro-inflammatory cytokine, interleukin-1 beta (IL-1β). Notably, both Aβ accumulation and hyperphosphorylation of Tau decreased and inhibited pyroptosis by downregulating the expression of IL-1β and IL-18, which can be attributed to the treatment of Sal. We further found that Sal can reverse the increased protein expression of TLR4, MyD88, NF-κB, P-NF-κB, NLRP3, ASC, cleaved Caspase-1, cleaved GSDMD, IL-1β, and IL-18 in vitro. The underlying mechanism may be through inhibiting TLR4/NF-κB/NLRP3/Caspase-1 signaling pathway. Our study highlights the importance of NLRP3 inflammasome-mediated pyroptosis in AD, and how the administration of pharmacological doses of Sal can inhibit NLRP3 inflammasome-mediated pyroptosis and ameliorate AD. Thus, we conclude that NLRP3 inflammasome-mediated pyroptosis plays a significant role in AD and Sal could be a therapeutic drug for AD.
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Affiliation(s)
- Yawen Cai
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yuhui Chai
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yu Fu
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yingdi Wang
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yiming Zhang
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Xue Zhang
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Lingpeng Zhu
- Center of Clinical Research, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China
- *Correspondence: Lingpeng Zhu
| | - Mingxing Miao
- Center of National Pharmaceutical Experimental Teaching Demonstration, China Pharmaceutical University, Nanjing, China
- Mingxing Miao
| | - Tianhua Yan
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
- Tianhua Yan
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