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Xie PL, Zheng MY, Han R, Chen WX, Mao JH. Pharmacological mTOR inhibitors in ameliorating Alzheimer's disease: current review and perspectives. Front Pharmacol 2024; 15:1366061. [PMID: 38873415 PMCID: PMC11169825 DOI: 10.3389/fphar.2024.1366061] [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: 01/05/2024] [Accepted: 04/25/2024] [Indexed: 06/15/2024] Open
Abstract
Traditionally, pharmacological mammalian/mechanistic targets of rapamycin (mTOR) kinase inhibitors have been used during transplantation and tumor treatment. Emerging pre-clinical evidence from the last decade displayed the surprising effectiveness of mTOR inhibitors in ameliorating Alzheimer's Disease (AD), a common neurodegenerative disorder characterized by progressive cognitive function decline and memory loss. Research shows mTOR activation as an early event in AD development, and inhibiting mTOR may promote the resolution of many hallmarks of Alzheimer's. Aberrant protein aggregation, including amyloid-beta (Aβ) deposition and tau filaments, and cognitive defects, are reversed upon mTOR inhibition. A closer inspection of the evidence highlighted a temporal dependence and a hallmark-specific nature of such beneficial effects. Time of administration relative to disease progression, and a maintenance of a functional lysosomal system, could modulate its effectiveness. Moreover, mTOR inhibition also exerts distinct effects between neurons, glial cells, and endothelial cells. Different pharmacological properties of the inhibitors also produce different effects based on different blood-brain barrier (BBB) entry capacities and mTOR inhibition sites. This questions the effectiveness of mTOR inhibition as a viable AD intervention strategy. In this review, we first summarize the different mTOR inhibitors available and their characteristics. We then comprehensively update and discuss the pre-clinical results of mTOR inhibition to resolve many of the hallmarks of AD. Key pathologies discussed include Aβ deposition, tauopathies, aberrant neuroinflammation, and neurovascular system breakdowns.
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Affiliation(s)
- Pei-Lun Xie
- University College London, London, United Kingdom
| | | | - Ran Han
- Dongfang Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Wei-Xin Chen
- Dongfang Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Jin-Hua Mao
- Beijing University of Chinese Medicine, Beijing, China
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Fu Y, Wang Y, Ren H, Guo X, Han L. Branched-chain amino acids and the risks of dementia, Alzheimer's disease, and Parkinson's disease. Front Aging Neurosci 2024; 16:1369493. [PMID: 38659706 PMCID: PMC11040674 DOI: 10.3389/fnagi.2024.1369493] [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: 01/12/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
Background We aimed to examine the association between blood levels of Branched-chain amino acids (BCAAs) - specifically isoleucine, leucine, and valine - and the susceptibility to three neurodegenerative disorders: dementia, Alzheimer's disease (AD), and Parkinson's disease (PD). Methods Based on data from the UK Biobank, a Cox proportional hazard regression model and a dose-response relationship were used to analyze the association between BCAAs and the risks of dementia, AD, and PD. We also generated a healthy lifestyle score and a polygenic risk score. Besides, we conducted a sensitivity analysis to ensure the robustness of our findings. Results After adjusting for multiple covariates, blood concentrations of isoleucine, leucine, and valine were significantly associated with a reduced risk of dementia and AD. This association remained robust even in sensitivity analyses. Similarly, higher levels of isoleucine and leucine in the blood were found to be associated with an increased risk of PD, but this positive correlation could potentially be explained by the presence of covariates. Further analysis using a dose-response approach revealed that a blood leucine concentration of 2.14 mmol/L was associated with the lowest risk of dementia. Conclusion BCAAs have the potential to serve as a biomarker for dementia and AD. However, the specific mechanism through which BCAAs are linked to the development of dementia, AD, and PD remains unclear and necessitates additional investigation.
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Affiliation(s)
- Yidong Fu
- Department of Rehabilitation Medicine, Ningbo No. 2 Hospital, Ningbo, China
| | - Yue Wang
- School of Public Health, Medical College of Soochow University, Suzhou, China
| | - Huiming Ren
- Department of Rehabilitation Medicine, Ningbo No. 2 Hospital, Ningbo, China
| | - Xu Guo
- Department of Rehabilitation Medicine, Ningbo No. 2 Hospital, Ningbo, China
| | - Liyuan Han
- Department of Clinical Epidemiology, Ningbo No. 2 Hospital, Ningbo, China
- Center for Cardiovascular and Cerebrovascular Epidemiology and Translational Medicine, Ningbo Institute of Life and Health Industry, University of Chinese Academy of Sciences, Ningbo, China
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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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Ranglani S, Ashton A, Mahfooz K, Komorowska J, Graur A, Kabbani N, Garcia-Rates S, Greenfield S. A Novel Bioactive Peptide, T14, Selectively Activates mTORC1 Signalling: Therapeutic Implications for Neurodegeneration and Other Rapamycin-Sensitive Applications. Int J Mol Sci 2023; 24:9961. [PMID: 37373106 DOI: 10.3390/ijms24129961] [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: 05/12/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
T14 modulates calcium influx via the α-7 nicotinic acetylcholine receptor to regulate cell growth. Inappropriate triggering of this process has been implicated in Alzheimer's disease (AD) and cancer, whereas T14 blockade has proven therapeutic potential in in vitro, ex vivo and in vivo models of these pathologies. Mammalian target of rapamycin complex 1 (mTORC1) is critical for growth, however its hyperactivation is implicated in AD and cancer. T14 is a product of the longer 30mer-T30. Recent work shows that T30 drives neurite growth in the human SH-SY5Y cell line via the mTOR pathway. Here, we demonstrate that T30 induces an increase in mTORC1 in PC12 cells, and ex vivo rat brain slices containing substantia nigra, but not mTORC2. The increase in mTORC1 by T30 in PC12 cells is attenuated by its blocker, NBP14. Moreover, in post-mortem human midbrain, T14 levels correlate significantly with mTORC1. Silencing mTORC1 reverses the effects of T30 on PC12 cells measured via AChE release in undifferentiated PC12 cells, whilst silencing mTORC2 does not. This suggests that T14 acts selectively via mTORC1. T14 blockade offers a preferable alternative to currently available blockers of mTOR as it would enable selective blockade of mTORC1, thereby reducing side effects associated with generalised mTOR blockade.
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Affiliation(s)
- Sanskar Ranglani
- Neuro Bio Ltd., Building F5, Culham Science Centre, Abingdon OX14 3DB, UK
| | - Anna Ashton
- Neuro Bio Ltd., Building F5, Culham Science Centre, Abingdon OX14 3DB, UK
| | - Kashif Mahfooz
- Neuro Bio Ltd., Building F5, Culham Science Centre, Abingdon OX14 3DB, UK
| | - Joanna Komorowska
- Neuro Bio Ltd., Building F5, Culham Science Centre, Abingdon OX14 3DB, UK
| | - Alexandru Graur
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
| | - Nadine Kabbani
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
| | - Sara Garcia-Rates
- Neuro Bio Ltd., Building F5, Culham Science Centre, Abingdon OX14 3DB, UK
| | - Susan Greenfield
- Neuro Bio Ltd., Building F5, Culham Science Centre, Abingdon OX14 3DB, UK
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Danics L, Abbas AA, Kis B, Pircs K. Fountain of youth—Targeting autophagy in aging. Front Aging Neurosci 2023; 15:1125739. [PMID: 37065462 PMCID: PMC10090449 DOI: 10.3389/fnagi.2023.1125739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 03/14/2023] [Indexed: 03/31/2023] Open
Abstract
As our society ages inexorably, geroscience and research focusing on healthy aging is becoming increasingly urgent. Macroautophagy (referred to as autophagy), a highly conserved process of cellular clearance and rejuvenation has attracted much attention due to its universal role in organismal life and death. Growing evidence points to autophagy process as being one of the key players in the determination of lifespan and health. Autophagy inducing interventions show significant improvement in organismal lifespan demonstrated in several experimental models. In line with this, preclinical models of age-related neurodegenerative diseases demonstrate pathology modulating effect of autophagy induction, implicating its potential to treat such disorders. In humans this specific process seems to be more complex. Recent clinical trials of drugs targeting autophagy point out some beneficial effects for clinical use, although with limited effectiveness, while others fail to show any significant improvement. We propose that using more human-relevant preclinical models for testing drug efficacy would significantly improve clinical trial outcomes. Lastly, the review discusses the available cellular reprogramming techniques used to model neuronal autophagy and neurodegeneration while exploring the existing evidence of autophagy’s role in aging and pathogenesis in human-derived in vitro models such as embryonic stem cells (ESCs), induced pluripotent stem cell derived neurons (iPSC-neurons) or induced neurons (iNs).
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Affiliation(s)
- Lea Danics
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
- Hungarian Centre of Excellence for Molecular Medicine - Semmelweis University (HCEMM-SU), Neurobiology and Neurodegenerative Diseases Research Group, Budapest, Hungary
- Eötvös Loránd Research Network and Semmelweis University (ELKH-SU), Cerebrovascular and Neurocognitive Disorders Research Group, Budapest, Hungary
| | - Anna Anoir Abbas
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
- Hungarian Centre of Excellence for Molecular Medicine - Semmelweis University (HCEMM-SU), Neurobiology and Neurodegenerative Diseases Research Group, Budapest, Hungary
| | - Balázs Kis
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
- Hungarian Centre of Excellence for Molecular Medicine - Semmelweis University (HCEMM-SU), Neurobiology and Neurodegenerative Diseases Research Group, Budapest, Hungary
| | - Karolina Pircs
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
- Hungarian Centre of Excellence for Molecular Medicine - Semmelweis University (HCEMM-SU), Neurobiology and Neurodegenerative Diseases Research Group, Budapest, Hungary
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
- *Correspondence: Karolina Pircs,
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Jiang G, Long Z, Wang Y, Wang Y, Xue P, Chen M, Yang K, Li W. Inhibition of mammalian target of rapamycin complex 1 in the brain microvascular endothelium ameliorates diabetic Aβ brain deposition and cognitive impairment via the sterol-regulatory element-binding protein 1/lipoprotein receptor-associated protein 1 signaling pathway. CNS Neurosci Ther 2023. [PMID: 36890627 DOI: 10.1111/cns.14133] [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: 09/21/2022] [Revised: 12/02/2022] [Accepted: 02/15/2023] [Indexed: 03/10/2023] Open
Abstract
AIMS Mammalian target of rapamycin complex 1 (mTORC1) is highly activated in diabetes, and the decrease of low-density lipoprotein receptor-associated protein 1 (LRP1) in brain microvascular endothelial cells (BMECs) is a key factor leading to amyloid-β (Aβ) deposition in the brain and diabetic cognitive impairment, but the relationship between them is still unknown. METHODS In vitro, BMECs were cultured with high glucose, and the activation of mTORC1 and sterol-regulatory element-binding protein 1 (SREBP1) was observed. mTORC1 was inhibited by rapamycin and small interfering RNA (siRNA) in BMECs. Betulin and siRNA inhibited SREBP1, observed the mechanism of mTORC1-mediated effects on Aβ efflux in BMECs through LRP1 under high-glucose conditions. Constructed cerebrovascular endothelial cell-specific Raptor-knockout (Raptorfl/+ ) mice to investigate the role of mTORC1 in regulating LRP1-mediated Aβ efflux and diabetic cognitive impairment at the tissue level. RESULTS mTORC1 activation was observed in HBMECs cultured in high glucose, and this change was confirmed in diabetic mice. Inhibiting mTORC1 corrected the reduction in Aβ efflux under high-glucose stimulation. In addition, high glucose activated the expression of SREBP1, and inhibiting of mTORC1 reduced the activation and expression of SREBP1. After inhibiting the activity of SREBP1, the presentation of LRP1 was improved, and the decrease of Aβ efflux mediated by high glucose was corrected. Raptorfl/+ diabetic mice had significantly inhibited activation of mTORC1 and SREBP1, increased LRP1 expression, increased Aβ efflux, and improved cognitive impairment. CONCLUSION Inhibiting mTORC1 in the brain microvascular endothelium ameliorates diabetic Aβ brain deposition and cognitive impairment via the SREBP1/LRP1 signaling pathway, suggesting that mTORC1 may be a potential target for the treatment of diabetic cognitive impairment.
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Affiliation(s)
- Gege Jiang
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhenzhen Long
- Xiang Yang No. 1 People Hospital, Affiliated Hospital of Hubei University Medicine, XiangYang, China
| | - Yaoling Wang
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yaofeng Wang
- Department of Hepatobiliary Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ping Xue
- Department of Geriatrics, Li-Yuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Minfang Chen
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kang Yang
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Li
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Cozachenco D, Ribeiro FC, Ferreira ST. Defective proteostasis in Alzheimer's disease. Ageing Res Rev 2023; 85:101862. [PMID: 36693451 DOI: 10.1016/j.arr.2023.101862] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 01/11/2023] [Accepted: 01/20/2023] [Indexed: 01/22/2023]
Abstract
The homeostasis of cellular proteins, or proteostasis, is critical for neuronal function and for brain processes, including learning and memory. Increasing evidence indicates that defective proteostasis contributes to the progression of neurodegenerative disorders, including Alzheimer's disease (AD), the most prevalent form of dementia in the elderly. Proteostasis comprises a set of cellular mechanisms that control protein synthesis, folding, post-translational modification and degradation, all of which are deregulated in AD. Importantly, deregulation of proteostasis plays a key role in synapse dysfunction and in memory impairment, the major clinical manifestation of AD. Here, we discuss molecular pathways involved in protein synthesis and degradation that are altered in AD, and possible pharmacological approaches to correct these defects.
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Affiliation(s)
- Danielle Cozachenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Felipe C Ribeiro
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Kumar S, Mehan S, Narula AS. Therapeutic modulation of JAK-STAT, mTOR, and PPAR-γ signaling in neurological dysfunctions. J Mol Med (Berl) 2023; 101:9-49. [PMID: 36478124 DOI: 10.1007/s00109-022-02272-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 10/10/2022] [Accepted: 11/11/2022] [Indexed: 12/12/2022]
Abstract
The cytokine-activated Janus kinase (JAK)-signal transducer and activator of transcription (STAT) cascade is a pleiotropic pathway that involves receptor subunit multimerization. The mammalian target of rapamycin (mTOR) is a ubiquitously expressed serine-threonine kinase that perceives and integrates a variety of intracellular and environmental stimuli to regulate essential activities such as cell development and metabolism. Peroxisome proliferator-activated receptor-gamma (PPARγ) is a prototypical metabolic nuclear receptor involved in neural differentiation and axon polarity. The JAK-STAT, mTOR, and PPARγ signaling pathways serve as a highly conserved signaling hub that coordinates neuronal activity and brain development. Additionally, overactivation of JAK/STAT, mTOR, and inhibition of PPARγ signaling have been linked to various neurocomplications, including neuroinflammation, apoptosis, and oxidative stress. Emerging research suggests that even minor disruptions in these cellular and molecular processes can have significant consequences manifested as neurological and neuropsychiatric diseases. Of interest, target modulators have been proven to alleviate neuronal complications associated with acute and chronic neurological deficits. This research-based review explores the therapeutic role of JAK-STAT, mTOR, and PPARγ signaling modulators in preventing neuronal dysfunctions in preclinical and clinical investigations.
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Affiliation(s)
- Sumit Kumar
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Punjab, Moga, India
| | - Sidharth Mehan
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Punjab, Moga, India.
| | - Acharan S Narula
- Narula Research, LLC, 107 Boulder Bluff, Chapel Hill, NC, 27516, USA
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Dysregulation of sphingosine-1-phosphate (S1P) and S1P receptor 1 signaling in the 5xFAD mouse model of Alzheimer's disease. Brain Res 2023; 1799:148171. [PMID: 36410428 DOI: 10.1016/j.brainres.2022.148171] [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: 08/25/2022] [Revised: 10/22/2022] [Accepted: 11/15/2022] [Indexed: 11/19/2022]
Abstract
Sphingolipid-1-phosphate (S1P) signaling through the activation S1P receptors (S1PRs) plays critical roles in cellular events in the brain. Aberrant S1P metabolism has been identified in the brains of Alzheimer's disease (AD) patients. Our recent studies have shown that treatment with fingolimod, an analog of sphingosine, provides neuroprotective effects in five familiar Alzheimer disease (5xFAD) transgenic mice, resulting in the reduction of amyloid-β (Aβ) neurotoxicity, inhibition of activation of microglia and astrocytes, increased hippocampal neurogenesis, and improved learning and memory. However, the pathways by which dysfunctional S1P and S1PR signaling may associate with the development of AD-like pathology remain unknown. In this study, we investigated the alteration of signaling of S1P/S1P receptor 1 (S1PR1), the most abundant S1PR subtype in the brain, in the cortex of 5xFAD transgenic mice at 3, 8, and 14 months of age. Compared to non-transgenic wildtype (WT) littermates, we found significant decreased levels of sphingosine kinases (SphKs), increased S1P lyase (S1PL), and increased S1PR1 in 8- and 14-month-old, but not in 3-month-old 5xFAD mice. Furthermore, we detected increased activation of the S1PR1 downstream pathway of Akt/mTor/Tau signaling in aging 5xFAD mice. Treatment with fingolimod from 1 to 8 months of age reversed the levels of SphKs, S1PL, and furthermore, those of S1PR1 and its downstream pathway of Akt/mTor/Tau signaling. Together the data reveal that dysregulation of S1P and S1PR signaling may associate with the development of AD-like pathology through Akt/mTor/Tau signaling.
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Cai HY, Hou SJ, Wen R, Feng QF, Xi YJ, Zhang SX, Qiao J, Wu MN. Causal Association Between mTOR-Dependent Protein Levels and Alzheimer's Disease: A Mendelian Randomization Study. J Alzheimers Dis 2023; 94:1477-1485. [PMID: 37393500 DOI: 10.3233/jad-230128] [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: 07/03/2023]
Abstract
BACKGROUND Most previous studies supported that the mammalian target of rapamycin (mTOR) is over-activated in Alzheimer's disease (AD) and exacerbates the development of AD. It is unclear whether the causal associations between the mTOR signaling-related protein and the risk for AD exist. OBJECTIVE This study aims to investigate the causal effects of the mTOR signaling targets on AD. METHODS We explored whether the risk of AD varied with genetically predicted AKT, RP-S6K, EIF4E-BP, eIF4E, eIF4A, and eIF4G circulating levels using a two-sample Mendelian randomization analysis. The summary data for targets of the mTOR signaling were acquired from published genome-wide association studies for the INTERVAL study. Genetic associations with AD were retrieved from the International Genomics of Alzheimer's Project. We utilized the inverse variance weighted as the primary approach to calculate the effect estimates. RESULTS The elevated levels of AKT (OR = 0.910, 95% CI=0.840-0.986, p = 0.02) and RP-S6K (OR = 0.910, 95% CI=0.840-0.986, p = 0.02) may decrease the AD risk. In contrast, the elevated eIF4E levels (OR = 1.805, 95% CI=1.002-1.174, p = 0.045) may genetically increase the AD risk. No statistical significance was identified for levels of EIF4-BP, eIF4A, and eIF4G with AD risk (p > 0.05). CONCLUSION There was a causal relationship between the mTOR signaling and the risk for AD. Activating AKT and RP-S6K, or inhibiting eIF4E may be potentially beneficial to the prevention and treatment of AD.
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Affiliation(s)
- Hong-Yan Cai
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China
- Department of Microbiology and Immunology, Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Si-Jia Hou
- Department of Neurology, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Rui Wen
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China
- Department of Microbiology and Immunology, Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Qi-Fan Feng
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China
- Department of Microbiology and Immunology, Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Yu-Jia Xi
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
- Shanxi Provincial Key Laboratory of Rheumatism Immune Microecology, Taiyuan, Shanxi Province, China
| | - Sheng-Xiao Zhang
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
- Shanxi Provincial Key Laboratory of Rheumatism Immune Microecology, Taiyuan, Shanxi Province, China
| | - Jun Qiao
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
- Shanxi Provincial Key Laboratory of Rheumatism Immune Microecology, Taiyuan, Shanxi Province, China
| | - Mei-Na Wu
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China
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Subramanian A, Tamilanban T, Alsayari A, Ramachawolran G, Wong LS, Sekar M, Gan SH, Subramaniyan V, Chinni SV, Izzati Mat Rani NN, Suryadevara N, Wahab S. Trilateral association of autophagy, mTOR and Alzheimer's disease: Potential pathway in the development for Alzheimer's disease therapy. Front Pharmacol 2022; 13:1094351. [PMID: 36618946 PMCID: PMC9817151 DOI: 10.3389/fphar.2022.1094351] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
The primary and considerable weakening event affecting elderly individuals is age-dependent cognitive decline and dementia. Alzheimer's disease (AD) is the chief cause of progressive dementia, and it is characterized by irreparable loss of cognitive abilities, forming senile plaques having Amyloid Beta (Aβ) aggregates and neurofibrillary tangles with considerable amounts of tau in affected hippocampus and cortex regions of human brains. AD affects millions of people worldwide, and the count is showing an increasing trend. Therefore, it is crucial to understand the underlying mechanisms at molecular levels to generate novel insights into the pathogenesis of AD and other cognitive deficits. A growing body of evidence elicits the regulatory relationship between the mammalian target of rapamycin (mTOR) signaling pathway and AD. In addition, the role of autophagy, a systematic degradation, and recycling of cellular components like accumulated proteins and damaged organelles in AD, is also pivotal. The present review describes different mechanisms and signaling regulations highlighting the trilateral association of autophagy, the mTOR pathway, and AD with a description of inhibiting drugs/molecules of mTOR, a strategic target in AD. Downregulation of mTOR signaling triggers autophagy activation, degrading the misfolded proteins and preventing the further accumulation of misfolded proteins that inhibit the progression of AD. Other target mechanisms such as autophagosome maturation, and autophagy-lysosomal pathway, may initiate a faulty autophagy process resulting in senile plaques due to defective lysosomal acidification and alteration in lysosomal pH. Hence, the strong link between mTOR and autophagy can be explored further as a potential mechanism for AD therapy.
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Affiliation(s)
- Arunkumar Subramanian
- Department of Pharmacology, SRM College of Pharmacy, SRM Institute of Science and Technology, Chengalpattu, Tamilnadu, India
| | - T. Tamilanban
- Department of Pharmacology, SRM College of Pharmacy, SRM Institute of Science and Technology, Chengalpattu, Tamilnadu, India,*Correspondence: T. Tamilanban, ; Gobinath Ramachawolran, ; Ling Shing Wong, ; Mahendran Sekar,
| | - Abdulrhman Alsayari
- Department of Pharmacognosy, College of Pharmacy, King Khalid University, Abha, Saudi Arabia,Complementary and Alternative Medicine Unit, King Khalid University, Abha, Saudi Arabia
| | - Gobinath Ramachawolran
- Department of Foundation, RCSI & UCD Malaysia Campus, Georgetown, Pulau Pinang, Malaysia,*Correspondence: T. Tamilanban, ; Gobinath Ramachawolran, ; Ling Shing Wong, ; Mahendran Sekar,
| | - Ling Shing Wong
- Faculty of Health and Life Sciences, INTI International University, Nilai, Malaysia,*Correspondence: T. Tamilanban, ; Gobinath Ramachawolran, ; Ling Shing Wong, ; Mahendran Sekar,
| | - Mahendran Sekar
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Health Sciences, Royal College of Medicine Perak, Universiti Kuala Lumpur, Ipoh, Perak, Malaysia,*Correspondence: T. Tamilanban, ; Gobinath Ramachawolran, ; Ling Shing Wong, ; Mahendran Sekar,
| | - Siew Hua Gan
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
| | - Vetriselvan Subramaniyan
- Faculty of Medicine, Bioscience and Nursing, MAHSA University, Bandar Saujana Putra, Selangor, Malaysia
| | - Suresh V. Chinni
- Department of Biochemistry, Faculty of Medicine, Bioscience, and Nursing, MAHSA University, Bandar Saujana Putra, Selangor, Malaysia,Department of Periodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - Nur Najihah Izzati Mat Rani
- Faculty of Pharmacy and Health Sciences, Royal College of Medicine Perak, Universiti Kuala Lumpur, Ipoh, Perak, Malaysia
| | - Nagaraja Suryadevara
- Faculty of Medicine, Bioscience and Nursing, MAHSA University, Bandar Saujana Putra, Selangor, Malaysia
| | - Shadma Wahab
- Department of Pharmacognosy, College of Pharmacy, King Khalid University, Abha, Saudi Arabia,Complementary and Alternative Medicine Unit, King Khalid University, Abha, Saudi Arabia
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12
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Ma N, Liang Y, Yue L, Liu P, Xu Y, Zhu C. The identities of insulin signaling pathway are affected by overexpression of Tau and its phosphorylation form. Front Aging Neurosci 2022; 14:1057281. [PMID: 36589543 PMCID: PMC9800792 DOI: 10.3389/fnagi.2022.1057281] [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: 09/29/2022] [Accepted: 11/25/2022] [Indexed: 12/23/2022] Open
Abstract
Introduction Hyperphosphorylated Tau formed neurofibrillary tangles was one of the major neuropathological hallmarks of Alzheimer's disease (AD). Dysfunctional insulin signaling in brain is involved in AD. However, the effect of Tau pathology on brain insulin resistance remains unclear. This study explored the effects of overexpressing wild-type Tau (WTau) or Tau with pseudo-phosphorylation at AT8 residues (PTau) on the insulin signaling pathway (ISP). Methods 293T cells or SY5Y cells overexpressing WTau or PTau were treated with or without insulin. The elements in ISP or the regulators of IPS were analyzed by immunoblotting, immunofluorescent staining and co-immunoprecipitation. Akt inhibitor MK2206 was used for evaluating the insulin signaling to downstream of mTOR in Tau overexpressing cells. The effects of anti-aging drug lonafarnib on ISP in WTau or PTau cells were also analyzed with immunoblotting. Considering lonafarnib is an inhibitor of FTase, the states of Rhes, one of FTase substrate in WTau or PTau cells were analyzed by drug affinity responsive target stability (DARTS) assay and the cellular thermal shift assay (CETSA). Results WTau or PTau overexpression in cells upregulated basal activity of elements in ISP in general. However, overexpression of WTau or PTau suppressed the ISP signaling transmission responses induced by insulin simulation, appearing relative higher response of IRS-1 phosphorylation at tyrosine 612 (IRS-1 p612) in upstream IPS, but a lower phosphorylation response of downstream IPS including mTOR, and its targets 4EPB1 and S6. This dysregulation of insulin evoked signaling transmission was more obvious in PTau cells. Suppressing Akt with MK2206 could compromise the levels of p-S6 and p-mTOR in WTau or PTau cells. Moreover, the changes of phosphatases detected in WTau and PTau cells may be related to ISP dysfunction. In addition, the effects of lonafarnib on the ISP in SY5Y cells with WTau and PTau overexpression were tested, which showed that lonafarnib treatment resulted in reducing the active levels of ISP elements in PTau cells but not in WTau cells. The differential effects are probably due to Tau phosphorylation modulating lonafarnib-induced alterations in Rhes, as revealed by DARTS assay. Conclusion and discussion Overexpression of Tau or Tau with pseudo-phosphorylation at AT8 residues could cause an upregulation of the basal/tonic ISP, but a suppression of insulin induced the phasic activation of ISP. This dysfunction of ISP was more obvious in cells overexpressing pseudo-phosphorylated Tau. These results implied that the dysfunction of ISP caused by Tau overexpression might impair the physiological fluctuation of neuronal functions in AD. The different effects of lonafarnib on ISP between WTau and PTau cells, indicating that Tau phosphorylation mediates an additional effect on ISP. This study provided a potential linkage of abnormal expression and phosphorylation of Tau to the ISP dysfunction in AD.
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Abstract
To maintain energy supply to the brain, a direct energy source called adenosine triphosphate (ATP) is produced by oxidative phosphorylation and aerobic glycolysis of glucose in the mitochondria and cytoplasm. Brain glucose metabolism is reduced in many neurodegenerative diseases, including Alzheimer's disease (AD), where it appears presymptomatically in a progressive and region-specific manner. Following dysregulation of energy metabolism in AD, many cellular repair/regenerative processes are activated to conserve the energy required for cell viability. Glucose metabolism plays an important role in the pathology of AD and is closely associated with the tricarboxylic acid cycle, type 2 diabetes mellitus, and insulin resistance. The glucose intake in neurons is from endothelial cells, astrocytes, and microglia. Damage to neurocentric glucose also damages the energy transport systems in AD. Gut microbiota is necessary to modulate bidirectional communication between the gastrointestinal tract and brain. Gut microbiota may influence the process of AD by regulating the immune system and maintaining the integrity of the intestinal barrier. Furthermore, some therapeutic strategies have shown promising therapeutic effects in the treatment of AD at different stages, including the use of antidiabetic drugs, rescuing mitochondrial dysfunction, and epigenetic and dietary intervention. This review discusses the underlying mechanisms of alterations in energy metabolism in AD and provides potential therapeutic strategies in the treatment of AD.
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Cheng X, Wei Y, Qian Z, Han L. Autophagy Balances Neuroinflammation in Alzheimer's Disease. Cell Mol Neurobiol 2022; 43:1537-1549. [PMID: 35960407 DOI: 10.1007/s10571-022-01269-6] [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: 05/21/2022] [Accepted: 07/29/2022] [Indexed: 01/20/2023]
Abstract
Autophagy is a highly evolutionary conserved process that degrades cytosolic macromolecules or damaged organelles (e.g., mitochondria), as well as intracellular pathogens for energy and survival. Dysfunction of autophagy has been associated with the pathologies of Alzheimer's disease (AD), including Aβ plaques and neurofibrillary tangles. Recently, the presence of sustained immune response in the brain has been considered a new core pathology in AD. Accumulating evidence suggests that autophagy activation may suppress inflammation response through degrading inflammasomes or pro-inflammatory cytokines and improving immune system function in both clinical trials and preclinical studies. This review provides an overview of updated information on autophagy and inflammation and their potential mediators in AD. In summary, we believe that understanding the relationship between autophagy and inflammation will provide insightful knowledge for future therapeutic implications in AD.
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Affiliation(s)
- Xuehua Cheng
- Department of TCM Geriatrics, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, People's Republic of China
| | - Yong Wei
- GeneScience Pharmaceuticals CoLtd., Changchun, 130012, People's Republic of China
| | - Zijun Qian
- Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai, 200071, People's Republic of China
| | - Li Han
- Department of TCM Geriatrics, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, People's Republic of China.
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15
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Li MZ, Liu EJ, Zhou QZ, Li SH, Liu SJ, Yu HT, Pan QH, Sun F, He T, Wang WJ, Ke D, Feng YQ, Li J, Wang JZ. Intracellular accumulation of tau inhibits autophagosome formation by activating TIA1-amino acid-mTORC1 signaling. Mil Med Res 2022; 9:38. [PMID: 35799293 PMCID: PMC9264508 DOI: 10.1186/s40779-022-00396-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 06/13/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer's disease (AD). This study aimed to investigate whether and how the accumulating tau may in turn affect autophagy. METHODS The primary hippocampal neurons, N2a and HEK293T cells with tau overexpression were respectively starved and treated with vinblastine to study the effects of tau on the initiating steps of autophagy, which was analysed by Student's two-tailed t-test. The rapamycin and concanamycin A were employed to inhibit the mammalian target of rapamycin kinase complex 1 (mTORC1) activity and the vacuolar H+-ATPase (v-ATPase) activity, respectively, which were analysed by One-way ANOVA with post hoc tests. The Western blotting, co-immunoprecipitation and immunofluorescence staining were conducted to gain insight into the mechanisms underlying the tau effects of mTORC1 signaling alterations, as analysed by Student's two-tailed t-test or One-way ANOVA with post hoc tests. The autophagosome formation was detected by immunofluorescence staining and transmission electron microscopy. The amino acids (AA) levels were detected by high performance liquid chromatography (HPLC). RESULTS We observed that overexpressing human full-length wild-type tau to mimic AD-like tau accumulation induced autophagy deficits. Further studies revealed that the increased tau could bind to the prion-related domain of T cell intracellular antigen 1 (PRD-TIA1) and this association significantly increased the intercellular level of amino acids (Leucine, P = 0.0038; Glutamic acid, P = 0.0348; Alanine, P = 0.0037; Glycine, P = 0.0104), with concordant upregulation of mTORC1 activity [phosphorylated eukaryotic translation initiation factor 4E-binding protein 1 (p-4EBP1), P < 0.0001; phosphorylated 70 kDa ribosomal protein S6 kinase 1 (p-p70S6K1), P = 0.0001, phosphorylated unc-51-like autophagy-activating kinase 1 (p-ULK1), P = 0.0015] and inhibition of autophagosome formation [microtubule-associated protein light chain 3 II (LC3 II), P = 0.0073; LC3 puncta, P < 0.0001]. As expected, this tau-induced deficit of autophagosome formation in turn aggravated tau accumulation. Importantly, we also found that blocking TIA1 and tau interaction by overexpressing PRD-TIA1, downregulating the endogenous TIA1 expression by shRNA, or downregulating tau protein level by a small proteolysis targeting chimera (PROTAC) could remarkably attenuate tau-induced autophagy impairment. CONCLUSIONS Our findings reveal that AD-like tau accumulation inhibits autophagosome formation and induces autophagy deficits by activating the TIA1/amino acid/mTORC1 pathway, and thus this work reveals new insight into tau-associated neurodegeneration and provides evidence supporting the use of new therapeutic targets for AD treatment and that of related tauopathies.
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Affiliation(s)
- Meng-Zhu Li
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.,Department of Neurosurgery, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, China
| | - En-Jie Liu
- Department of Pathology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Qiu-Zhi Zhou
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Shi-Hong Li
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Shi-Jie Liu
- Department of Chemistry, Wuhan University, Wuhan, 430072, China
| | - Hai-Tao Yu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Qi-Hang Pan
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.,Department of Neurosurgery, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, China
| | - Fei Sun
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Ting He
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Wei-Jin Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Dan Ke
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yu-Qi Feng
- Department of Chemistry, Wuhan University, Wuhan, 430072, China
| | - Jun Li
- Department of Neurosurgery, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, China.
| | - Jian-Zhi Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China. .,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226000, Jiangsu, China.
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16
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Guerrero-Navarro L, Jansen-Dürr P, Cavinato M. Age-Related Lysosomal Dysfunctions. Cells 2022; 11:cells11121977. [PMID: 35741106 PMCID: PMC9221958 DOI: 10.3390/cells11121977] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/10/2022] [Accepted: 06/16/2022] [Indexed: 12/10/2022] Open
Abstract
Organismal aging is normally accompanied by an increase in the number of senescent cells, growth-arrested metabolic active cells that affect normal tissue function. These cells present a series of characteristics that have been studied over the last few decades. The damage in cellular organelles disbalances the cellular homeostatic processes, altering the behavior of these cells. Lysosomal dysfunction is emerging as an important factor that could regulate the production of inflammatory molecules, metabolic cellular state, or mitochondrial function.
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Affiliation(s)
- Lena Guerrero-Navarro
- Institute for Biomedical Aging Research, Universität Innsbruck, 6020 Innsbruck, Austria; (L.G.-N.); (P.J.-D.)
- Center for Molecular Biosciences Innsbruck, Innrain 58, 6020 Innsbruck, Austria
| | - Pidder Jansen-Dürr
- Institute for Biomedical Aging Research, Universität Innsbruck, 6020 Innsbruck, Austria; (L.G.-N.); (P.J.-D.)
- Center for Molecular Biosciences Innsbruck, Innrain 58, 6020 Innsbruck, Austria
| | - Maria Cavinato
- Institute for Biomedical Aging Research, Universität Innsbruck, 6020 Innsbruck, Austria; (L.G.-N.); (P.J.-D.)
- Center for Molecular Biosciences Innsbruck, Innrain 58, 6020 Innsbruck, Austria
- Correspondence:
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17
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Rezaeian AH, Wei W, Inuzuka H. The regulation of neuronal autophagy and cell survival by MCL1 in Alzheimer's disease. ACTA MATERIA MEDICA 2022; 1:42-55. [PMID: 35233562 DOI: 10.15212/amm-2021-0002] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Maintaining neuronal integrity and functions requires precise mechanisms controlling organelle and protein quality. Alzheimer's disease (AD) is characterized by functional defects in the clearance and recycling of intracellular components. As such, neuronal homeostasis involves autophagy, mitophagy, and apoptosis. Compromised activity in these cellular processes may cause pathological phenotypes of AD. Dysfunction of mitochondria is one of the hallmarks of AD. Mitophagy is a critical mitochondria quality control system, and the impaired mitophagy is observed in AD. Myeloid cell leukemia 1 (MCL1), a member of the pro-survival B-cell lymphoma protein 2 (BCL2) family, is a mitochondria-targeted protein that contributes to maintaining mitochondrial integrity. Mcl1 knockout mice display peri-implantation lethality. The studies on conditional Mcl1 knockout mice demonstrate that MCL1 plays a central role in neurogenesis and neuronal survival during brain development. Accumulating evidence reveals the critical role of MCL1 as a regulator of neuronal autophagy, mitophagy, and survival. In this review, we discuss the emerging neuroprotective function of MCL1 and how dysregulation of MCL1 signaling is involved in the pathogenesis of AD. As the pro-survival BCL2 family of proteins are promising targets of pharmacological intervention with BH3 mimetic drugs, we also discuss the promise of MCL1-targeting therapy in AD.
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Affiliation(s)
- Abdol-Hossein Rezaeian
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Hiroyuki Inuzuka
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
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18
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Impairment of the autophagy-lysosomal pathway in Alzheimer's diseases: Pathogenic mechanisms and therapeutic potential. Acta Pharm Sin B 2022; 12:1019-1040. [PMID: 35530153 PMCID: PMC9069408 DOI: 10.1016/j.apsb.2022.01.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/09/2021] [Accepted: 12/16/2021] [Indexed: 01/18/2023] Open
Abstract
Alzheimer's disease (AD), the most common neurodegenerative disorder, is characterized by memory loss and cognitive dysfunction. The accumulation of misfolded protein aggregates including amyloid beta (Aβ) peptides and microtubule associated protein tau (MAPT/tau) in neuronal cells are hallmarks of AD. So far, the exact underlying mechanisms for the aetiologies of AD have not been fully understood and the effective treatment for AD is limited. Autophagy is an evolutionarily conserved cellular catabolic process by which damaged cellular organelles and protein aggregates are degraded via lysosomes. Recently, there is accumulating evidence linking the impairment of the autophagy–lysosomal pathway with AD pathogenesis. Interestingly, the enhancement of autophagy to remove protein aggregates has been proposed as a promising therapeutic strategy for AD. Here, we first summarize the recent genetic, pathological and experimental studies regarding the impairment of the autophagy–lysosomal pathway in AD. We then describe the interplay between the autophagy–lysosomal pathway and two pathological proteins, Aβ and MAPT/tau, in AD. Finally, we discuss potential therapeutic strategies and small molecules that target the autophagy–lysosomal pathway for AD treatment both in animal models and in clinical trials. Overall, this article highlights the pivotal functions of the autophagy–lysosomal pathway in AD pathogenesis and potential druggable targets in the autophagy–lysosomal pathway for AD treatment.
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19
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De Felice FG, Gonçalves RA, Ferreira ST. Impaired insulin signalling and allostatic load in Alzheimer disease. Nat Rev Neurosci 2022; 23:215-230. [DOI: 10.1038/s41583-022-00558-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2022] [Indexed: 12/14/2022]
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20
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Caponio D, Veverová K, Zhang SQ, Shi L, Wong G, Vyhnalek M, Fang EF. Compromised autophagy and mitophagy in brain ageing and Alzheimer's diseases. AGING BRAIN 2022; 2:100056. [PMID: 36908880 PMCID: PMC9997167 DOI: 10.1016/j.nbas.2022.100056] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/04/2022] [Accepted: 11/16/2022] [Indexed: 11/25/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most persistent and devastating neurodegenerative disorders of old age, and is characterized clinically by an insidious onset and a gradual, progressive deterioration of cognitive abilities, ranging from loss of memory to impairment of judgement and reasoning. Despite years of research, an effective cure is still not available. Autophagy is the cellular 'garbage' clearance system which plays fundamental roles in neurogenesis, neuronal development and activity, and brain health, including memory and learning. A selective sub-type of autophagy is mitophagy which recognizes and degrades damaged or superfluous mitochondria to maintain a healthy and necessary cellular mitochondrial pool. However, emerging evidence from animal models and human samples suggests an age-dependent reduction of autophagy and mitophagy, which are also compromised in AD. Upregulation of autophagy/mitophagy slows down memory loss and ameliorates clinical features in animal models of AD. In this review, we give an overview of autophagy and mitophagy and their link to the progression of AD. We also summarize approaches to upregulate autophagy/mitophagy. We hypothesize that age-dependent compromised autophagy/mitophagy is a cause of brain ageing and a risk factor for AD, while restoration of autophagy/mitophagy to more youthful levels could return the brain to health.
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Affiliation(s)
- Domenica Caponio
- Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, 1478 Lørenskog, Norway
| | - Kateřina Veverová
- Memory Clinic, Department of Neurology, Charles University, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| | - Shi-Qi Zhang
- Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, 1478 Lørenskog, Norway
| | - Liu Shi
- Department of Psychiatry, University of Oxford, Oxford, UK.,Novo Nordisk Research Centre Oxford (NNRCO)
| | - Garry Wong
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Macau 999078, China
| | - Martin Vyhnalek
- Memory Clinic, Department of Neurology, Charles University, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| | - Evandro F Fang
- Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, 1478 Lørenskog, Norway.,The Norwegian Centre on Healthy Ageing (NO-Age), Oslo, Norway
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21
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Nieto-Torres JL, Hansen M. Macroautophagy and aging: The impact of cellular recycling on health and longevity. Mol Aspects Med 2021; 82:101020. [PMID: 34507801 PMCID: PMC8671213 DOI: 10.1016/j.mam.2021.101020] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/11/2021] [Accepted: 08/31/2021] [Indexed: 02/08/2023]
Abstract
Aging is associated with many deleterious changes at the cellular level, including the accumulation of potentially toxic components that can have devastating effects on health. A key protective mechanism to this end is the cellular recycling process called autophagy. During autophagy, damaged or surplus cellular components are delivered to acidic vesicles called lysosomes, that secure degradation and recycling of the components. Numerous links between autophagy and aging exist. Autophagy declines with age, and increasing evidence suggests that this reduction plays important roles in both physiological aging and the development of age-associated disorders. Studies in pharmacologically and genetically manipulated model organisms indicate that defects in autophagy promote age-related diseases, and conversely, that enhancement of autophagy has beneficial effects on both healthspan and lifespan. Here, we review our current understanding of the role of autophagy in different physiological processes and their molecular links with aging and age-related diseases. We also highlight some recent advances in the field that could accelerate the development of autophagy-based therapeutic interventions.
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Affiliation(s)
- Jose L Nieto-Torres
- Sanford Burnham Prebys Medical Discovery Institute. Program of Development, Aging, and Regeneration, La Jolla, CA, USA
| | - Malene Hansen
- Sanford Burnham Prebys Medical Discovery Institute. Program of Development, Aging, and Regeneration, La Jolla, CA, USA.
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22
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Hernandez SJ, Fote G, Reyes-Ortiz AM, Steffan JS, Thompson LM. Cooperation of cell adhesion and autophagy in the brain: Functional roles in development and neurodegenerative disease. Matrix Biol Plus 2021; 12:100089. [PMID: 34786551 PMCID: PMC8579148 DOI: 10.1016/j.mbplus.2021.100089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/11/2021] [Accepted: 10/18/2021] [Indexed: 12/19/2022] Open
Abstract
Cellular adhesive connections directed by the extracellular matrix (ECM) and maintenance of cellular homeostasis by autophagy are seemingly disparate functions that are molecularly intertwined, each regulating the other. This is an emerging field in the brain where the interplay between adhesion and autophagy functions at the intersection of neuroprotection and neurodegeneration. The ECM and adhesion proteins regulate autophagic responses to direct protein clearance and guide regenerative programs that go awry in brain disorders. Concomitantly, autophagic flux acts to regulate adhesion dynamics to mediate neurite outgrowth and synaptic plasticity with functional disruption contributed by neurodegenerative disease. This review highlights the cooperative exchange between cellular adhesion and autophagy in the brain during health and disease. As the mechanistic alliance between adhesion and autophagy has been leveraged therapeutically for metastatic disease, understanding overlapping molecular functions that direct the interplay between adhesion and autophagy might uncover therapeutic strategies to correct or compensate for neurodegeneration.
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Affiliation(s)
- Sarah J. Hernandez
- Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697, USA
- Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA
| | - Gianna Fote
- Department of Biological Chemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Andrea M. Reyes-Ortiz
- Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA
- Department of Biological Chemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Joan S. Steffan
- Psychaitry and Human Behavior, University of California Irvine, Irvine, CA 92697, USA
- Institute of Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92617, USA
| | - Leslie M. Thompson
- Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697, USA
- Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA
- Department of Biological Chemistry, University of California Irvine, Irvine, CA 92697, USA
- Psychaitry and Human Behavior, University of California Irvine, Irvine, CA 92697, USA
- Institute of Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92617, USA
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23
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Barthelson K, Newman M, Lardelli M. Brain transcriptomes of zebrafish and mouse Alzheimer's disease knock-in models imply early disrupted energy metabolism. Dis Model Mech 2021; 15:273566. [PMID: 34842276 PMCID: PMC8807579 DOI: 10.1242/dmm.049187] [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: 06/26/2021] [Accepted: 11/17/2021] [Indexed: 11/21/2022] Open
Abstract
Energy production is the most fundamentally important cellular activity supporting all other functions, particularly in highly active organs, such as brains. Here, we summarise transcriptome analyses of young adult (pre-disease) brains from a collection of 11 early-onset familial Alzheimer's disease (EOFAD)-like and non-EOFAD-like mutations in three zebrafish genes. The one cellular activity consistently predicted as affected by only the EOFAD-like mutations is oxidative phosphorylation, which produces most of the energy of the brain. All the mutations were predicted to affect protein synthesis. We extended our analysis to knock-in mouse models of APOE alleles and found the same effect for the late onset Alzheimer's disease risk allele ε4. Our results support a common molecular basis for the initiation of the pathological processes leading to both early and late onset forms of Alzheimer's disease, and illustrate the utility of zebrafish and knock-in single EOFAD mutation models for understanding the causes of this disease. Summary: Young adult zebrafish mutants and a mouse model of a genetic variant promoting early- and late-onset Alzheimer's disease, respectively, share changes in brain gene expression, indicating disturbance of oxidative phosphorylation.
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Affiliation(s)
- Karissa Barthelson
- Alzheimer's Disease Genetics Laboratory, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
| | - Morgan Newman
- Alzheimer's Disease Genetics Laboratory, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
| | - Michael Lardelli
- Alzheimer's Disease Genetics Laboratory, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
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24
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Gadhave K, Kumar D, Uversky VN, Giri R. A multitude of signaling pathways associated with Alzheimer's disease and their roles in AD pathogenesis and therapy. Med Res Rev 2021; 41:2689-2745. [PMID: 32783388 PMCID: PMC7876169 DOI: 10.1002/med.21719] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/13/2020] [Accepted: 07/29/2020] [Indexed: 02/06/2023]
Abstract
The exact molecular mechanisms associated with Alzheimer's disease (AD) pathology continue to represent a mystery. In the past decades, comprehensive data were generated on the involvement of different signaling pathways in the AD pathogenesis. However, the utilization of signaling pathways as potential targets for the development of drugs against AD is rather limited due to the immense complexity of the brain and intricate molecular links between these pathways. Therefore, finding a correlation and cross-talk between these signaling pathways and establishing different therapeutic targets within and between those pathways are needed for better understanding of the biological events responsible for the AD-related neurodegeneration. For example, autophagy is a conservative cellular process that shows link with many other AD-related pathways and is crucial for maintenance of the correct cellular balance by degrading AD-associated pathogenic proteins. Considering the central role of autophagy in AD and its interplay with many other pathways, the finest therapeutic strategy to fight against AD is the use of autophagy as a target. As an essential step in this direction, this comprehensive review represents recent findings on the individual AD-related signaling pathways, describes key features of these pathways and their cross-talk with autophagy, represents current drug development, and introduces some of the multitarget beneficial approaches and strategies for the therapeutic intervention of AD.
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Affiliation(s)
- Kundlik Gadhave
- School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh, 175005, India
| | - Deepak Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh, 175005, India
| | - Vladimir N. Uversky
- Department of Molecular Medicine and Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Rajanish Giri
- School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh, 175005, India
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Querfurth H, Lee HK. Mammalian/mechanistic target of rapamycin (mTOR) complexes in neurodegeneration. Mol Neurodegener 2021; 16:44. [PMID: 34215308 PMCID: PMC8252260 DOI: 10.1186/s13024-021-00428-5] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 02/01/2021] [Indexed: 12/12/2022] Open
Abstract
Novel targets to arrest neurodegeneration in several dementing conditions involving misfolded protein accumulations may be found in the diverse signaling pathways of the Mammalian/mechanistic target of rapamycin (mTOR). As a nutrient sensor, mTOR has important homeostatic functions to regulate energy metabolism and support neuronal growth and plasticity. However, in Alzheimer's disease (AD), mTOR alternately plays important pathogenic roles by inhibiting both insulin signaling and autophagic removal of β-amyloid (Aβ) and phospho-tau (ptau) aggregates. It also plays a role in the cerebrovascular dysfunction of AD. mTOR is a serine/threonine kinase residing at the core in either of two multiprotein complexes termed mTORC1 and mTORC2. Recent data suggest that their balanced actions also have implications for Parkinson's disease (PD) and Huntington's disease (HD), Frontotemporal dementia (FTD) and Amyotrophic Lateral Sclerosis (ALS). Beyond rapamycin; an mTOR inhibitor, there are rapalogs having greater tolerability and micro delivery modes, that hold promise in arresting these age dependent conditions.
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Affiliation(s)
- Henry Querfurth
- Department of Neurology, Tufts Medical Center, Boston, Massachusetts, USA.
| | - Han-Kyu Lee
- Department of Neurology, Tufts Medical Center, Boston, Massachusetts, USA
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26
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Genipin Attenuates Tau Phosphorylation and Aβ Levels in Cellular Models of Alzheimer's Disease. Mol Neurobiol 2021; 58:4134-4144. [PMID: 33948899 DOI: 10.1007/s12035-021-02389-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/05/2021] [Indexed: 10/21/2022]
Abstract
Alzheimer's disease (AD) is a devastating brain disorder characterized by neurofibrillary tangles and amyloid plaques. Inhibiting Tau protein and amyloid-beta (Aβ) production or removing these molecules is considered potential therapeutic strategies for AD. Genipin is an aglycone and is isolated from the extract of Gardenia jasminoides Ellis fruit. In this study, the effect and molecular mechanisms of genipin on the inhibition of Tau aggregation and Aβ generation were investigated. The results showed that genipin bound to Tau and protected against heparin-induced Tau fibril formation. Moreover, genipin suppressed Tau phosphorylation probably by downregulating the expression of CDK5 and GSK-3β, and activated mTOR-dependent autophagy via the SIRT1/LKB1/AMPK signaling pathway in Tau-overexpressing cells. In addition, genipin decreased Aβ production by inhibiting BACE1 expression through the PERK/eIF2α signaling pathway in N2a/SweAPP cells. These data indicated that genipin could effectively lead to a significant reduction of phosphorylated Tau level and Aβ generation in vitro, suggesting that genipin might be developed into an effective therapeutic complement or a potential nutraceutical for preventing AD.
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27
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mTOR Attenuation with Rapamycin Reverses Neurovascular Uncoupling and Memory Deficits in Mice Modeling Alzheimer's Disease. J Neurosci 2021; 41:4305-4320. [PMID: 33888602 DOI: 10.1523/jneurosci.2144-20.2021] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 02/19/2021] [Accepted: 03/02/2021] [Indexed: 02/07/2023] Open
Abstract
Vascular dysfunction is a universal feature of aging and decreased cerebral blood flow has been identified as an early event in the pathogenesis of Alzheimer's disease (AD). Cerebrovascular dysfunction in AD includes deficits in neurovascular coupling (NVC), a mechanism that ensures rapid delivery of energy substrates to active neurons through the blood supply. The mechanisms underlying NVC impairment in AD, however, are not well understood. We have previously shown that mechanistic/mammalian target of rapamycin (mTOR) drives cerebrovascular dysfunction in models of AD by reducing the activity of endothelial nitric oxide synthase (eNOS), and that attenuation of mTOR activity with rapamycin is sufficient to restore eNOS-dependent cerebrovascular function. Here we show mTOR drives NVC impairments in an AD model through the inhibition of neuronal NOS (nNOS)- and non-NOS-dependent components of NVC, and that mTOR attenuation with rapamycin is sufficient to restore NVC and even enhance it above WT responses. Restoration of NVC and concomitant reduction of cortical amyloid-β levels effectively treated memory deficits in 12-month-old hAPP(J20) mice. These data indicate that mTOR is a critical driver of NVC dysfunction and underlies cognitive impairment in an AD model. Together with our previous findings, the present studies suggest that mTOR promotes cerebrovascular dysfunction in AD, which is associated with early disruption of nNOS activation, through its broad negative impact on nNOS as well as on non-NOS components of NVC. Our studies highlight the potential of mTOR attenuation as an efficacious treatment for AD and potentially other neurologic diseases of aging.SIGNIFICANCE STATEMENT Failure of the blood flow response to neuronal activation [neurovascular coupling (NVC)] in a model of AD precedes the onset of AD-like cognitive symptoms and is driven, to a large extent, by mammalian/mechanistic target of rapamycin (mTOR)-dependent inhibition of nitric oxide synthase activity. Our studies show that mTOR also drives AD-like failure of non-nitric oxide (NO)-mediated components of NVC. Thus, mTOR attenuation may serve to treat AD, where we find that neuronal NO synthase is profoundly reduced early in disease progression, and potentially other neurologic diseases of aging with cerebrovascular dysfunction as part of their etiology.
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Structure-based modification of pyrazolone derivatives to inhibit mTORC1 by targeting the leucyl-tRNA synthetase-RagD interaction. Bioorg Chem 2021; 112:104907. [PMID: 33979735 DOI: 10.1016/j.bioorg.2021.104907] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/21/2021] [Accepted: 04/07/2021] [Indexed: 12/13/2022]
Abstract
The enzyme leucyl-tRNA synthetase (LRS) and the amino acid leucine regulate the mechanistic target of rapamycin (mTOR) signaling pathway. Leucine-dependent mTORC1 activation depends on GTPase activating protein events mediated by LRS. In a prior study, compound BC-LI-0186 was discovered and shown to interfere with the mTORC1 signaling pathway by inhibiting the LRS-RagD interaction. However, BC-LI-0186 exhibited poor solubility and was metabolized by human liver microsomes. In this study, in silico physicochemical properties and metabolite analysis of BC-LI-0186 are used to investigate the addition of functional groups to improve solubility and microsomal stability. In vitro experiments demonstrated that 7b and 8a had improved chemical properties while still maintaining inhibitory activity against mTORC1. The results suggest a new strategy for the discovery of novel drug candidates and the treatment of diverse mTORC1-related diseases.
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29
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Ferreira ST. Brain insulin, insulin-like growth factor 1 and glucagon-like peptide 1 signalling in Alzheimer's disease. J Neuroendocrinol 2021; 33:e12959. [PMID: 33739563 DOI: 10.1111/jne.12959] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 02/07/2021] [Accepted: 02/12/2021] [Indexed: 12/13/2022]
Abstract
Although the brain was once considered an insulin-independent organ, insulin signalling is now recognised as being central to neuronal health and to the function of synapses and brain circuits. Defective brain insulin signalling, as well as related signalling by insulin-like growth factor 1 (IGF-1), is associated with neurological disorders, including Alzheimer's disease, suggesting that cognitive impairment could be related to a state of brain insulin resistance. Here, I briefly review key epidemiological/clinical evidence of the association between diabetes, cognitive decline and AD, as well as findings of reduced components of insulin signalling in AD brains, which led to the initial suggestion that AD could be a type of brain diabetes. Particular attention is given to recent studies illuminating mechanisms leading to neuronal insulin resistance as a key driver of cognitive impairment in AD. Evidence of impaired IGF-1 signalling in AD is also examined. Finally, we discuss potentials and possible limitations of recent and on-going therapeutic approaches based on our increased understanding of the roles of brain signalling by insulin, IGF-1 and glucagon-like peptide 1 in AD.
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Affiliation(s)
- Sergio T Ferreira
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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30
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Wang Y, Chen F, Wang P, Mana L, Sheng N, Huang S. Study on myelin injury of AD mice treated with Shenzhiling oral liquid in the PI3K/Akt-mTOR pathway. Int J Immunopathol Pharmacol 2021; 34:2058738420923907. [PMID: 32462951 PMCID: PMC7262987 DOI: 10.1177/2058738420923907] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Shenzhiling oral liquid (SZL) is a Traditional Chinese Medicine (TCM) compound to
be approved by the China Food and Drug Administration (CFDA) (Z20120010) for the
treatment of mild-to-moderate Alzheimer’s disease (AD). However, its mechanism
in early AD is not clear. We studied its mechanism in protecting myelin.
Three-month-old APPswe/PS1dE9double transgenic mice were used as AD model and
wild-type C57BL/6 mice were used as control. After 3-month intervention, the
Morris water maze was used to detect behavioural changes. Myelin mTOR pathway
(PI3K, p-PI3K, Akt, p-Akt, mTOR, p-mTOR), myelin basic protein (MBP) and
postsynaptic density protein 95 (PSD95) were detected by immunohistochemistry
and western blot and reverse transcriptase polymerase chain reaction (RT-PCR).
After 3 months of SZL treatment, compared with the model group (M), SZL
medium-dose (SM) and SZL low-dose groups (SL) exhibited increased staying and
crossing results in Morris water maze (P < 0.05). Compared
with M, PI3K-positive cells in SM and SL groups were increased
(P < 0.01), p-PI3K expression increased in the Donepezil
group (D), SZL high-dose group (SH) and SM (P < 0.05);
number of Akt-positive cells and Akt expression in D, SM and SL were increased
(P < 0.01, P < 0.05); number of
p-Akt- and mTOR-positive cells and mTOR expression in all drug-treated groups
were significantly increased (P < 0.01); p-Akt and p-mTOR
expression increased in all drug-treated groups (P < 0.05,
P < 0.01); MBP expression in D and SH increased
(P < 0.05), while in SM and SL it increased more
significantly (P < 0.01); and PSD95 expression in D, SM and
SL was increased (P < 0.05). RT-PCR results showed that
compared with M, PI3K mRNA and Akt mRNA expression in all drug-treated groups
increased, but there was no statistical difference
(P > 0.05), mTOR mRNA expression in all the drug-treated
groups increased significantly (P < 0.01) and MBP mRNA and
PSD95 mRNA expression in D and SH increased (P < 0.05). SZL
oral liquid could play a role in myelin protection in early AD.
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Affiliation(s)
- Yahan Wang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,Key Laboratory of Pharmacology of Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, China
| | - Fang Chen
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,Key Laboratory of Pharmacology of Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, China.,Rehabilitation Department, The Hospital of Traditional Chinese Medicine Affiliated to Xinjiang Medical University, Ürümqi, China
| | - Pengwen Wang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,Key Laboratory of Pharmacology of Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, China
| | - Lulu Mana
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,Key Laboratory of Pharmacology of Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, China.,College of Chinese Medicine, Xinjiang Medical University, Ürümqi, China
| | - Ning Sheng
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,Key Laboratory of Pharmacology of Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, China.,Oncology Department, Beijing University of Chinese Medicine (BUCM) Affiliated Zaozhuang Hospital, Zaozhuang, China
| | - Shuaiyang Huang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,Key Laboratory of Pharmacology of Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, China
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31
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Abstract
Cells metabolize nutrients for biosynthetic and bioenergetic needs to fuel growth and proliferation. The uptake of nutrients from the environment and their intracellular metabolism is a highly controlled process that involves cross talk between growth signaling and metabolic pathways. Despite constant fluctuations in nutrient availability and environmental signals, normal cells restore metabolic homeostasis to maintain cellular functions and prevent disease. A central signaling molecule that integrates growth with metabolism is the mechanistic target of rapamycin (mTOR). mTOR is a protein kinase that responds to levels of nutrients and growth signals. mTOR forms two protein complexes, mTORC1, which is sensitive to rapamycin, and mTORC2, which is not directly inhibited by this drug. Rapamycin has facilitated the discovery of the various functions of mTORC1 in metabolism. Genetic models that disrupt either mTORC1 or mTORC2 have expanded our knowledge of their cellular, tissue, as well as systemic functions in metabolism. Nevertheless, our knowledge of the regulation and functions of mTORC2, particularly in metabolism, has lagged behind. Since mTOR is an important target for cancer, aging, and other metabolism-related pathologies, understanding the distinct and overlapping regulation and functions of the two mTOR complexes is vital for the development of more effective therapeutic strategies. This review discusses the key discoveries and recent findings on the regulation and metabolic functions of the mTOR complexes. We highlight findings from cancer models but also discuss other examples of the mTOR-mediated metabolic reprogramming occurring in stem and immune cells, type 2 diabetes/obesity, neurodegenerative disorders, and aging.
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Affiliation(s)
- Angelia Szwed
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey
| | - Eugene Kim
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey
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32
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Chen H, Chen F, Zhang M, Chen Y, Cui L, Liang C. A Review of APOE Genotype-Dependent Autophagic Flux Regulation in Alzheimer's Disease. J Alzheimers Dis 2021; 84:535-555. [PMID: 34569952 DOI: 10.3233/jad-210602] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Autophagy is a basic physiological process maintaining cell renewal, the degradation of dysfunctional organelles, and the clearance of abnormal proteins and has recently been identified as a main mechanism underlying the onset and progression of Alzheimer's disease (AD). The APOE ɛ4 genotype is the strongest genetic determinant of AD pathogenesis and initiates autophagic flux at different times. This review synthesizes the current knowledge about the potential pathogenic effects of ApoE4 on autophagy and describes its associations with the biological hallmarks of autophagy and AD from a novel perspective. Via a remarkable variety of widely accepted signaling pathway markers, such as mTOR, TFEB, SIRT1, LC3, p62, LAMP1, LAMP2, CTSD, Rabs, and V-ATPase, ApoE isoforms differentially modulate autophagy initiation; membrane expansion, recruitment, and enclosure; autophagosome and lysosome fusion; and lysosomal degradation. Although the precise pathogenic mechanism varies for different genes and proteins, the dysregulation of autophagic flux is a key mechanism on which multiple pathogenic processes converge.
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Affiliation(s)
- Huiyi Chen
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
- Yuebei People's Hospital, Affiliated Hospital of Shantou University Medical College, Shaoguan, China
| | - Feng Chen
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Miaoping Zhang
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Yanting Chen
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Lili Cui
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Chunmei Liang
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
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33
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Zhang W, Feng C, Jiang H. Novel target for treating Alzheimer's Diseases: Crosstalk between the Nrf2 pathway and autophagy. Ageing Res Rev 2021; 65:101207. [PMID: 33144123 DOI: 10.1016/j.arr.2020.101207] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 10/02/2020] [Accepted: 10/27/2020] [Indexed: 02/06/2023]
Abstract
In mammals, the Keap1-Nrf2-ARE pathway (henceforth, "the Nrf2 pathway") and autophagy are major intracellular defence systems that combat oxidative damage and maintain homeostasis. p62/SQSTM1, a ubiquitin-binding autophagy receptor protein, links the Nrf2 pathway and autophagy. Phosphorylation of p62 dramatically enhances its affinity for Keap1, which induces Keap1 to release Nrf2, and the p62-Keap1 heterodimer recruits LC3 and mediates the permanent degradation of Keap1 in the selective autophagy pathway. Eventually, Nrf2 accumulates in the cytoplasm and then translocates into the nucleus to activate the transcription of downstream genes that encode antioxidant enzymes, which protect cells from oxidative damage. Since Nrf2 also upregulates the expression of the p62 gene, a p62-Keap1-Nrf2 positive feedback loop is created that further enhances the protective effect on cells. Studies have shown that the p62-activated noncanonical Nrf2 pathway is an important marker of neurodegenerative diseases. The p62-Keap1-Nrf2 positive feedback loop and the Nrf2 pathway are involved in eliminating the ROS and protein aggregates induced by AD. Therefore, maintaining the homeostasis of the p62-Keap1-Nrf2 positive feedback loop, which is a bridge between the Nrf2 pathway and autophagy, may be a potential target for the treatment of AD.
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Affiliation(s)
- Weiwei Zhang
- Department of Health Laboratory Technology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning 110122, People's Republic of China
| | - Cong Feng
- Department of Health Laboratory Technology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning 110122, People's Republic of China
| | - Hong Jiang
- Department of Health Laboratory Technology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning 110122, People's Republic of China.
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34
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MicroRNAs Regulating Autophagy in Neurodegeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1208:191-264. [PMID: 34260028 DOI: 10.1007/978-981-16-2830-6_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Social and economic impacts of neurodegenerative diseases (NDs) become more prominent in our constantly aging population. Currently, due to the lack of knowledge about the aetiology of most NDs, only symptomatic treatment is available for patients. Hence, researchers and clinicians are in need of solid studies on pathological mechanisms of NDs. Autophagy promotes degradation of pathogenic proteins in NDs, while microRNAs post-transcriptionally regulate multiple signalling networks including autophagy. This chapter will critically discuss current research advancements in the area of microRNAs regulating autophagy in NDs. Moreover, we will introduce basic strategies and techniques used in microRNA research. Delineation of the mechanisms contributing to NDs will result in development of better approaches for their early diagnosis and effective treatment.
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35
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Martínez-Cué C, Rueda N. Signalling Pathways Implicated in Alzheimer's Disease Neurodegeneration in Individuals with and without Down Syndrome. Int J Mol Sci 2020; 21:E6906. [PMID: 32962300 PMCID: PMC7555886 DOI: 10.3390/ijms21186906] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 02/07/2023] Open
Abstract
Down syndrome (DS), the most common cause of intellectual disability of genetic origin, is characterized by alterations in central nervous system morphology and function that appear from early prenatal stages. However, by the fourth decade of life, all individuals with DS develop neuropathology identical to that found in sporadic Alzheimer's disease (AD), including the development of amyloid plaques and neurofibrillary tangles due to hyperphosphorylation of tau protein, loss of neurons and synapses, reduced neurogenesis, enhanced oxidative stress, and mitochondrial dysfunction and neuroinflammation. It has been proposed that DS could be a useful model for studying the etiopathology of AD and to search for therapeutic targets. There is increasing evidence that the neuropathological events associated with AD are interrelated and that many of them not only are implicated in the onset of this pathology but are also a consequence of other alterations. Thus, a feedback mechanism exists between them. In this review, we summarize the signalling pathways implicated in each of the main neuropathological aspects of AD in individuals with and without DS as well as the interrelation of these pathways.
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Affiliation(s)
- Carmen Martínez-Cué
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Cantabria, 39011 Santander, Spain;
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36
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Abdullah A, Mohd Murshid N, Makpol S. Antioxidant Modulation of mTOR and Sirtuin Pathways in Age-Related Neurodegenerative Diseases. Mol Neurobiol 2020; 57:5193-5207. [PMID: 32865663 DOI: 10.1007/s12035-020-02083-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/19/2020] [Indexed: 12/11/2022]
Abstract
In the human body, cell division and metabolism are expected to transpire uneventfully for approximately 25 years. Then, secondary metabolism and cell damage products accumulate, and ageing phenotypes are acquired, causing the progression of disease. Among these age-related diseases, neurodegenerative diseases have attracted considerable attention because of their irreversibility, the absence of effective treatment and their relationship with social and economic pressures. Mechanistic (formerly mammalian) target of rapamycin (mTOR), sirtuin (SIRT) and insulin/insulin growth factor 1 (IGF1) signalling pathways are among the most important pathways in ageing-associated conditions, such as neurodegeneration. These longevity-related pathways are associated with a diversity of various processes, including metabolism, cognition, stress reaction and brain plasticity. In this review, we discuss the roles of sirtuin and mTOR in ageing and neurodegeneration, with an emphasis on their regulation of autophagy, apoptosis and mitochondrial energy metabolism. The intervention of neurodegeneration using potential antioxidants, including vitamins, phytochemicals, resveratrol, herbals, curcumin, coenzyme Q10 and minerals, specifically aimed at retaining mitochondrial function in the treatment of Alzheimer's disease, Parkinson's disease and Huntington's disease is highlighted.
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Affiliation(s)
- Asmaa Abdullah
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Level 17, Preclinical Building, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, 56000, Kuala Lumpur, Malaysia
| | - Nuraqila Mohd Murshid
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Level 17, Preclinical Building, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, 56000, Kuala Lumpur, Malaysia
| | - Suzana Makpol
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Level 17, Preclinical Building, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, 56000, Kuala Lumpur, Malaysia.
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37
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Gourmaud S, Shou H, Irwin DJ, Sansalone K, Jacobs LM, Lucas TH, Marsh ED, Davis KA, Jensen FE, Talos DM. Alzheimer-like amyloid and tau alterations associated with cognitive deficit in temporal lobe epilepsy. Brain 2020; 143:191-209. [PMID: 31834353 DOI: 10.1093/brain/awz381] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 10/08/2019] [Accepted: 10/17/2019] [Indexed: 01/27/2023] Open
Abstract
Temporal lobe epilepsy represents a major cause of drug-resistant epilepsy. Cognitive impairment is a frequent comorbidity, but the mechanisms are not fully elucidated. We hypothesized that the cognitive impairment in drug-resistant temporal lobe epilepsy could be due to perturbations of amyloid and tau signalling pathways related to activation of stress kinases, similar to those observed in Alzheimer's disease. We examined these pathways, as well as amyloid-β and tau pathologies in the hippocampus and temporal lobe cortex of drug-resistant temporal lobe epilepsy patients who underwent temporal lobe resection (n = 19), in comparison with age- and region-matched samples from neurologically normal autopsy cases (n = 22). Post-mortem temporal cortex samples from Alzheimer's disease patients (n = 9) were used as positive controls to validate many of the neurodegeneration-related antibodies. Western blot and immunohistochemical analysis of tissue from temporal lobe epilepsy cases revealed increased phosphorylation of full-length amyloid precursor protein and its associated neurotoxic cleavage product amyloid-β*56. Pathological phosphorylation of two distinct tau species was also increased in both regions, but increases in amyloid-β1-42 peptide, the main component of amyloid plaques, were restricted to the hippocampus. Furthermore, several major stress kinases involved in the development of Alzheimer's disease pathology were significantly activated in temporal lobe epilepsy brain samples, including the c-Jun N-terminal kinase and the protein kinase R-like endoplasmic reticulum kinase. In temporal lobe epilepsy cases, hippocampal levels of phosphorylated amyloid precursor protein, its pro-amyloidogenic processing enzyme beta-site amyloid precursor protein cleaving enzyme 1, and both total and hyperphosphorylated tau expression, correlated with impaired preoperative executive function. Our study suggests that neurodegenerative and stress-related processes common to those observed in Alzheimer's disease may contribute to cognitive impairment in drug-resistant temporal lobe epilepsy. In particular, we identified several stress pathways that may represent potential novel therapeutic targets.
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Affiliation(s)
- Sarah Gourmaud
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Haochang Shou
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David J Irwin
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Penn Frontotemporal Degeneration Center, University of Pennsylvania, Philadelphia, PA, USA
| | - Kimberly Sansalone
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Leah M Jacobs
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Timothy H Lucas
- Department of Neurosurgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Eric D Marsh
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Kathryn A Davis
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Frances E Jensen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Delia M Talos
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Moon GJ, Shin M, Kim SR. Upregulation of Neuronal Rheb(S16H) for Hippocampal Protection in the Adult Brain. Int J Mol Sci 2020; 21:E2023. [PMID: 32188096 PMCID: PMC7139780 DOI: 10.3390/ijms21062023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 12/20/2022] Open
Abstract
Ras homolog protein enriched in brain (Rheb) is a key activator of mammalian target of rapamycin complex 1 (mTORC1). The activation of mTORC1 by Rheb is associated with various processes such as protein synthesis, neuronal growth, differentiation, axonal regeneration, energy homeostasis, autophagy, and amino acid uptake. In addition, Rheb-mTORC1 signaling plays a crucial role in preventing the neurodegeneration of hippocampal neurons in the adult brain. Increasing evidence suggests that the constitutive activation of Rheb has beneficial effects against neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Our recent studies revealed that adeno-associated virus serotype 1 (AAV1) transduction with Rheb(S16H), a constitutively active form of Rheb, exhibits neuroprotective properties through the induction of various neurotrophic factors, promoting neurotrophic interactions between neurons and astrocytes in the hippocampus of the adult brain. This review provides compelling evidence for the therapeutic potential of AAV1-Rheb(S16H) transduction in the hippocampus of the adult brain by exploring its neuroprotective effects and mechanisms.
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Affiliation(s)
- Gyeong Joon Moon
- BK21 plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea;
| | - Minsang Shin
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Korea;
- Department of Microbiology, School of Medicine, Kyungpook National University, Daegu 41944, Korea
| | - Sang Ryong Kim
- BK21 plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea;
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Korea;
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39
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Gureev AP, Popov VN, Starkov AA. Crosstalk between the mTOR and Nrf2/ARE signaling pathways as a target in the improvement of long-term potentiation. Exp Neurol 2020; 328:113285. [PMID: 32165256 DOI: 10.1016/j.expneurol.2020.113285] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 02/22/2020] [Accepted: 03/08/2020] [Indexed: 12/15/2022]
Abstract
In recent years, a significant progress was made in understanding molecular mechanisms of long-term memory. Long-term memory formation requires strengthening of neuronal connections (LTP, long-term potentiation) associated with structural rearrangement of neurons. The key role in the synthesis of proteins essential for these rearrangements belong to mTOR (mammalian target of rapamycin) complexes and signaling pathways involved in mTOR regulation. Suppression of mTOR activity may impair synaptic plasticity and long-term memory, while mTOR activation inhibits autophagy, thereby potentiating amyloidosis and development of Alzheimer's disease (AD) accompanied by irreversible memory loss. Because of this, suppression/inhibition of mTOR might have unpredictable consequences on memory. The Nrf2/ARE signaling pathway affects almost all mitochondrial processes. The activation of this pathway improves memory and exhibits therapeutic effect in AD. In this review, we discuss the crosstalk between the Nrf2/ARE signaling and mTOR in the maintenance of synaptic plasticity. Nrf2 pathway can be activated by pharmacological agents and by changes in mitochondria functioning accompanying various neuronal dysfunctions.
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Affiliation(s)
- Artem P Gureev
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russia
| | - Vasily N Popov
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russia; Voronezh State University of Engineering Technologies, Voronezh, Russia
| | - Anatoly A Starkov
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
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40
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Polis B, Samson AO. Role of the metabolism of branched-chain amino acids in the development of Alzheimer's disease and other metabolic disorders. Neural Regen Res 2020; 15:1460-1470. [PMID: 31997805 PMCID: PMC7059578 DOI: 10.4103/1673-5374.274328] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Alzheimer’s disease is an incurable chronic neurodegenerative disorder and the leading cause of dementia, imposing a growing economic burden upon society. The disease progression is associated with gradual deposition of amyloid plaques and the formation of neurofibrillary tangles within the brain parenchyma, yet severe dementia is the culminating phase of the enduring pathology. Converging evidence suggests that Alzheimer’s disease-related cognitive decline is the outcome of an extremely complex and persistent pathophysiological process. The disease is characterized by distinctive abnormalities apparent at systemic, histological, macromolecular, and biochemical levels. Moreover, besides the well-defined and self-evident characteristic profuse neurofibrillary tangles, dystrophic neurites, and amyloid-beta deposits, the Alzheimer’s disease-associated pathology includes neuroinflammation, substantial neuronal loss, apoptosis, extensive DNA damage, considerable mitochondrial malfunction, compromised energy metabolism, and chronic oxidative stress. Likewise, distinctive metabolic dysfunction has been named a leading cause and a hallmark of Alzheimer’s disease that is apparent decades prior to disease manifestation. State-of-the-art metabolomics studies demonstrate that altered branched-chain amino acids (BCAAs) metabolism accompanies Alzheimer’s disease development. Lower plasma valine levels are correlated with accelerated cognitive decline, and, conversely, an increase in valine concentration is associated with reduced risk of Alzheimer’s disease. Additionally, a clear BCAAs-related metabolic signature has been identified in subjects with obesity, diabetes, and atherosclerosis. Also, arginine metabolism is dramatically altered in Alzheimer’s disease human brains and animal models. Accordingly, a potential role of the urea cycle in the Alzheimer’s disease development has been hypothesized, and preclinical studies utilizing intervention in the urea cycle and/or BCAAs metabolism have demonstrated clinical potential. Continual failures to offer a competent treatment strategy directed against amyloid-beta or Tau proteins-related lesions, which could face all challenges of the multifaceted Alzheimer’s disease pathology, led to the hypothesis that hyperphosphorylated Tau and deposited amyloid-beta proteins are just hallmarks or epiphenomena, but not the ultimate causes of Alzheimer’s disease. Therefore, approaches targeting amyloid-beta or Tau are not adequate to cure the disease. Accordingly, the modern scientific vision of Alzheimer’s disease etiology and pathogenesis must reach beyond the hallmarks, and look for alternative strategies and areas of research.
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Affiliation(s)
- Baruh Polis
- Drug Discovery Laboratory, The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Abraham O Samson
- Drug Discovery Laboratory, The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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Moon GJ, Kim S, Jeon MT, Lee KJ, Jang IS, Nakamura M, Kim SR. Therapeutic Potential of AAV1-Rheb(S16H) Transduction Against Alzheimer's Disease. J Clin Med 2019; 8:jcm8122053. [PMID: 31766645 PMCID: PMC6947419 DOI: 10.3390/jcm8122053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/14/2019] [Accepted: 11/19/2019] [Indexed: 12/22/2022] Open
Abstract
We recently reported that adeno-associated virus serotype 1-constitutively active Ras homolog enriched in brain [AAV1-Rheb(S16H)] transduction of hippocampal neurons could induce neuron-astroglia interactions in the rat hippocampus in vivo, resulting in neuroprotection. However, it remains uncertain whether AAV1-Rheb(S16H) transduction induces neurotrophic effects and preserves the cognitive memory in an animal model of Alzheimer’s disease (AD) with characteristic phenotypic features, such as β-amyloid (Aβ) accumulation and cognitive impairments. To assess the therapeutic potential of Rheb(S16H) in AD, we have examined the beneficial effects of AAV1-Rheb(S16H) administration in the 5XFAD mouse model. Rheb(S16H) transduction of hippocampal neurons in the 5XFAD mice increased the levels of neurotrophic signaling molecules, including brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF), and their corresponding receptors, tropomyosin receptor kinase B (TrkB) and CNTF receptor α subunit (CNTFRα), respectively. In addition, Rheb(S16H) transduction inhibited Aβ production and accumulation in the hippocampus of 5XFAD mice and protected the decline of long-term potentiation (LTP), resulting in the prevention of cognitive impairments, which was demonstrated using novel object recognition testing. These results indicate that Rheb(S16H) transduction of hippocampal neurons may have therapeutic potential in AD by inhibiting Aβ accumulation and preserving LTP associated with cognitive memory.
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Affiliation(s)
- Gyeong Joon Moon
- School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (G.J.M.); (S.K.); (M.-T.J.)
- BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea
| | - Sehwan Kim
- School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (G.J.M.); (S.K.); (M.-T.J.)
- BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea
| | - Min-Tae Jeon
- School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (G.J.M.); (S.K.); (M.-T.J.)
- BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea
| | - Kea Joo Lee
- Neural Circuits Research Group, Korea Brain Research Institute, Daegu 41062, Korea;
| | - Il-Sung Jang
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Korea;
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea;
| | - Michiko Nakamura
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea;
| | - Sang Ryong Kim
- School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (G.J.M.); (S.K.); (M.-T.J.)
- BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Korea;
- Institute of Life Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea
- Correspondence:
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Mozafari N, Farjadian F, Mohammadi Samani S, Azadi S, Azadi A. Simvastatin-chitosan-citicoline conjugates nanoparticles as the co-delivery system in Alzheimer susceptible patients. Int J Biol Macromol 2019; 156:1396-1407. [PMID: 31760027 DOI: 10.1016/j.ijbiomac.2019.11.180] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/15/2019] [Accepted: 11/20/2019] [Indexed: 12/17/2022]
Abstract
The main goal of this study was the preparation and characterization of a chitosan-based system for co-delivery of simvastatin and citicoline to overcome simvastatin unwanted side effects in Alzheimer's disease. This conjugated complex was synthesized in three steps, and 1HNMR, FTIR, and UV-Vis spectroscopy confirmed its success. The simvastatin conjugation rate to chitosan was 1.67 times more than citicoline. X-ray diffraction results showed that the crystalline property of both drugs converted to an amorphous state during the synthesis of the conjugated form. Further, SEM images revealed that the developed nanoparticles have a spherical shape with a size between 100 and 300 nm. Another characterization test was RBC hemolysis, with the lowest value at 6.04% and the highest value at 89.56% and became much lower after preparing nanoparticles using the ionotropic technique. TEM characterized the nanoparticles and showed that the gelation technique stabilized the particles.
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Affiliation(s)
- Negin Mozafari
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmaceutics, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Fatemeh Farjadian
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Soliman Mohammadi Samani
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmaceutics, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Soha Azadi
- Department of Pharmaceutics, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Clinical Pharmacy, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amir Azadi
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmaceutics, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.
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43
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Lanzillotta C, Di Domenico F, Perluigi M, Butterfield DA. Targeting Mitochondria in Alzheimer Disease: Rationale and Perspectives. CNS Drugs 2019; 33:957-969. [PMID: 31410665 PMCID: PMC6825561 DOI: 10.1007/s40263-019-00658-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A decline in mitochondrial function plays a key role in the aging process and increases the incidence of age-related disorders, including Alzheimer disease (AD). Mitochondria-the power station of the organism-can affect several different cellular activities, including abnormal cellular energy generation, response to toxic insults, regulation of metabolism, and execution of cell death. In AD subjects, mitochondria are characterized by impaired function such as lowered oxidative phosphorylation, decreased adenosine triphosphate production, significant increased reactive oxygen species generation, and compromised antioxidant defense. The current review discusses the most relevant mitochondrial defects that are considered to play a significant role in AD and that may offer promising therapeutic targets for the treatment/prevention of AD. In addition, we discuss mechanisms of action and translational potential of some promising mitochondrial and bioenergetic therapeutics for AD including compounds able to potentiate energy production, antioxidants to scavenge reactive oxygen species and reduce oxidative damage, glucose metabolism, and candidates that target mitophagy. While mitochondrial therapeutic strategies have shown promise at the preclinical stage, there has been little progress in clinical trials. Thus, there is an urgent need to better understand the mechanisms regulating mitochondrial homeostasis in order to identify powerful drug candidates that target 'in and out' the mitochondria to preserve cognitive functions.
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Affiliation(s)
- Chiara Lanzillotta
- Department of Biochemical Sciences, Sapienza University of Rome, 00185, Rome, Italy
| | - Fabio Di Domenico
- Department of Biochemical Sciences, Sapienza University of Rome, 00185, Rome, Italy
| | - Marzia Perluigi
- Department of Biochemical Sciences, Sapienza University of Rome, 00185, Rome, Italy
| | - D Allan Butterfield
- Department of Chemistry, University of Kentucky, Lexington, KY, 40506-0055, USA.
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, 40506-0055, USA.
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44
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Yang Y, Wang Z, Cao Y, Liu J, Li P, Li H, Liu M. Yizhiqingxin Formula Alleviates Cognitive Deficits and Enhances Autophagy via mTOR Signaling Pathway Modulation in Early Onset Alzheimer's Disease Mice. Front Pharmacol 2019; 10:1041. [PMID: 31607908 PMCID: PMC6758600 DOI: 10.3389/fphar.2019.01041] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/16/2019] [Indexed: 01/09/2023] Open
Abstract
Alzheimer’s disease (AD) is the most common type of dementia worldwide. The deposition of amyloid β (Aβ) is one of the most important pathological changes in AD. Autophagy, which mediates degradation of toxic proteins and maintains normal neuronal function, is dysfunctional in AD; dysfunctional autophagy is believed to be a critical pathological feature of AD. Here, we evaluated the in vitro and in vivo effects of a traditional Chinese medicinal formula called Yizhiqingxin formula (YQF) on autophagy. We determined that treatment with a high dose of YQF improved spatial memory and decreased the hippocampal Aβ burden in APP/PS1 mice, an early onset AD model. Transmission electron microscopy and immunohistochemical data revealed that YQF enhanced autophagosome formation and also increased the levels of LC3II/LC3I and Beclin1. Further, we found that YQF treatment promoted autophagic activity by inhibiting the phosphorylation of the Mammalian target of rapamycin (mTOR) at the Ser2448 site. Moreover, the level of 4EBP1 increased after YQF intervention, indicating a suppression of mTOR signaling. YQF was also found to promote autophagosome degradation, as indicated by the decreased p62 levels and increased cathepsin D and V-ATPase levels. Taken together, YQF could improve spatial learning in APP/PS1 mice and ameliorate the accumulation of Aβ while promoting autophagy via mTOR pathway modulation.
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Affiliation(s)
- Yang Yang
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zhiyong Wang
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yu Cao
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jiangang Liu
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Peng Li
- Beijing Key Laboratory of Pharmacology of Chinese Materia Region, Institute of Basic Medical Sciences of Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hao Li
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Meixia Liu
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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Rosa JM, Pazini FL, Olescowicz G, Camargo A, Moretti M, Gil-Mohapel J, Rodrigues ALS. Prophylactic effect of physical exercise on Aβ 1-40-induced depressive-like behavior: Role of BDNF, mTOR signaling, cell proliferation and survival in the hippocampus. Prog Neuropsychopharmacol Biol Psychiatry 2019; 94:109646. [PMID: 31078612 DOI: 10.1016/j.pnpbp.2019.109646] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 05/02/2019] [Accepted: 05/08/2019] [Indexed: 12/17/2022]
Abstract
Alzheimer's disease (AD) is characterized by progressive cognitive impairments as well as non-cognitive symptoms such as depressed mood. Physical exercise has been proposed as a preventive strategy against AD and depression, an effect that may be related, at least partially, to its ability to prevent impairments on cell proliferation and neuronal survival in the hippocampus, a structure implicated in both cognition and affective behavior. Here, we investigated the ability of treadmill exercise (4 weeks) to counteract amyloid β1-40 peptide-induced depressive-like and anxiety-like behavior in mice. Moreover, we addressed the role of the BDNF/mTOR intracellular signaling pathway as well as hippocampal cell proliferation and survival in the effects of physical exercise and/or Aβ1-40. Aβ1-40 administration (400 pmol/mouse, i.c.v.) increased immobility time and reduced the latency to immobility in the forced swim test, a finding indicative of depressive-like behavior. In addition, Aβ1-40 administration also decreased time spent in the center of the open field and increased grooming and defecation, alterations indicative of anxiety-like behavior. These behavioral alterations were accompanied by a reduction in the levels of mature BDNF and mTOR (Ser2448) phosphorylation in the hippocampus. In addition, Aß1-40 administration reduced cell proliferation and survival in the ventral, dorsal and entire dentate gyrus of the hippocampus. Importantly, most of these behavioral, neurochemical and structural impairments induced by Aβ1-40 were not observed in mice subjected to 4 weeks of treadmill exercise. These findings indicate that physical exercise has the potential to prevent the occurrence of early emotional disturbances associated with AD and this appears to be mediated, at least in part, by modulation of hippocampal BDNF and mTOR signaling as well as through promotion of cell proliferation and survival in the hippocampal DG.
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Affiliation(s)
- Julia M Rosa
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Francis L Pazini
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Gislaine Olescowicz
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Anderson Camargo
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Morgana Moretti
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Joana Gil-Mohapel
- Division of Medical Sciences, University of Victoria, Island Medical Program, Faculty of Medicine, University of British Columbia, Victoria, British Columbia, Canada
| | - Ana Lúcia S Rodrigues
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, Florianópolis, Santa Catarina 88040-900, Brazil.
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Mechanisms Associated with Type 2 Diabetes as a Risk Factor for Alzheimer-Related Pathology. Mol Neurobiol 2019; 56:5815-5834. [PMID: 30684218 DOI: 10.1007/s12035-019-1475-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/10/2019] [Indexed: 12/19/2022]
Abstract
Current evidence suggests dementia and pathology in Alzheimer's Disease (AD) are both dependent and independent of amyloid processing and can be induced by multiple 'hits' on vital neuronal functions. Type 2 diabetes (T2D) poses the most important risk factor for developing AD after ageing and dysfunctional IR/PI3K/Akt signalling is a major contributor in both diseases. We developed a model of T2D, coupling subdiabetogenic doses of streptozotocin (STZ) with a human junk food (HJF) diet to more closely mimic the human condition. Over 35 weeks, this induced classic signs of T2D (hyperglycemia and insulin dysfunction) and a modest, but stable deficit in spatial recognition memory, with very little long-term modification of proteins in or associated with IR/PI3K/Akt signalling in CA1 of the hippocampus. Intracerebroventricular infusion of soluble amyloid beta 42 (Aβ42) to mimic the early preclinical rise in Aβ alone induced a more severe, but short-lasting deficits in memory and deregulation of proteins. Infusion of Aβ on the T2D phenotype exacerbated and prolonged the memory deficits over approximately 4 months, and induced more severe aberrant regulation of proteins associated with autophagy, inflammation and glucose uptake from the periphery. A mild form of environmental enrichment transiently rescued memory deficits and could reverse the regulation of some, but not all protein changes. Together, these data identify mechanisms by which T2D could create a modest dysfunctional neuronal milieu via multiple and parallel inputs that permits the development of pathological events identified in AD and memory deficits when Aβ levels are transiently effective in the brain.
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Kaeberlein M, Galvan V. Rapamycin and Alzheimer's disease: Time for a clinical trial? Sci Transl Med 2019; 11:eaar4289. [PMID: 30674654 PMCID: PMC6762017 DOI: 10.1126/scitranslmed.aar4289] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 06/08/2018] [Indexed: 12/16/2022]
Abstract
The drug rapamycin has beneficial effects in a number of animal models of neurodegeneration and aging including mouse models of Alzheimer's disease. Despite its compelling preclinical record, no clinical trials have tested rapamycin or other mTOR inhibitors in patients with Alzheimer's disease. We argue that such clinical trials should be undertaken.
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Affiliation(s)
- Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98045, USA.
| | - Veronica Galvan
- Department of Cellular and Integrative Physiology, Barshop Institute for Longevity and Aging Studies and Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, TX 78229, USA.
- Department of Veterans Affairs, South Texas Veterans Health Care System and Geriatric Research Education and Clinical Center, San Antonio, TX 78229, USA
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48
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Morris G, Berk M, Maes M, Puri BK. Could Alzheimer's Disease Originate in the Periphery and If So How So? Mol Neurobiol 2019; 56:406-434. [PMID: 29705945 PMCID: PMC6372984 DOI: 10.1007/s12035-018-1092-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 04/17/2018] [Indexed: 12/11/2022]
Abstract
The classical amyloid cascade model for Alzheimer's disease (AD) has been challenged by several findings. Here, an alternative molecular neurobiological model is proposed. It is shown that the presence of the APOE ε4 allele, altered miRNA expression and epigenetic dysregulation in the promoter region and exon 1 of TREM2, as well as ANK1 hypermethylation and altered levels of histone post-translational methylation leading to increased transcription of TNFA, could variously explain increased levels of peripheral and central inflammation found in AD. In particular, as a result of increased activity of triggering receptor expressed on myeloid cells 2 (TREM-2), the presence of the apolipoprotein E4 (ApoE4) isoform, and changes in ANK1 expression, with subsequent changes in miR-486 leading to altered levels of protein kinase B (Akt), mechanistic (previously mammalian) target of rapamycin (mTOR) and signal transducer and activator of transcription 3 (STAT3), all of which play major roles in microglial activation, proliferation and survival, there is activation of microglia, leading to the subsequent (further) production of cytokines, chemokines, nitric oxide, prostaglandins, reactive oxygen species, inducible nitric oxide synthase and cyclooxygenase-2, and other mediators of inflammation and neurotoxicity. These changes are associated with the development of amyloid and tau pathology, mitochondrial dysfunction (including impaired activity of the electron transport chain, depleted basal mitochondrial potential and oxidative damage to key tricarboxylic acid enzymes), synaptic dysfunction, altered glycogen synthase kinase-3 (GSK-3) activity, mTOR activation, impairment of autophagy, compromised ubiquitin-proteasome system, iron dyshomeostasis, changes in APP translation, amyloid plaque formation, tau hyperphosphorylation and neurofibrillary tangle formation.
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Affiliation(s)
- Gerwyn Morris
- IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Deakin University, P.O. Box 291, Geelong, Victoria, Australia
| | - Michael Berk
- IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Deakin University, P.O. Box 291, Geelong, Victoria, Australia
- Department of Psychiatry, Level 1 North, Main Block, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
- Florey Institute for Neuroscience and Mental Health, Kenneth Myer Building, University of Melbourne, 30 Royal Parade, Parkville, Victoria, Australia
- Orygen, The National Centre of Excellence in Youth Mental Health, 35 Poplar Rd, Parkville, Victoria, Australia
| | - Michael Maes
- IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Deakin University, P.O. Box 291, Geelong, Victoria, Australia
- Department of Psychiatry, Chulalongkorn University, Bangkok, Thailand
| | - Basant K Puri
- Department of Medicine, Hammersmith Hospital, Imperial College London, London, UK.
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Hernández F, Llorens-Martín M, Bolós M, Pérez M, Cuadros R, Pallas-Bazarra N, Zabala JC, Avila J. New Beginnings in Alzheimer’s Disease: The Most Prevalent Tauopathy. J Alzheimers Dis 2018; 64:S529-S534. [DOI: 10.3233/jad-179916] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Félix Hernández
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
- CIBERNED, Madrid, Spain
| | - María Llorens-Martín
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
- CIBERNED, Madrid, Spain
- Department of Molecular Biology, Faculty of Science, Universidad Autonoma de Madrid, Spain
| | - Marta Bolós
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
- CIBERNED, Madrid, Spain
| | - Mar Pérez
- Departamento de Anatomía Histología y Neurociencia, Facultad de Medicina UAM, Madrid, Spain
| | - Raquel Cuadros
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
- CIBERNED, Madrid, Spain
| | - Noemí Pallas-Bazarra
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
- CIBERNED, Madrid, Spain
| | - Juan C. Zabala
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Jesús Avila
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
- CIBERNED, Madrid, Spain
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50
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Braidy N, Essa MM, Poljak A, Selvaraju S, Al-Adawi S, Manivasagm T, Thenmozhi AJ, Ooi L, Sachdev P, Guillemin GJ. Consumption of pomegranates improves synaptic function in a transgenic mice model of Alzheimer's disease. Oncotarget 2018; 7:64589-64604. [PMID: 27486879 PMCID: PMC5323101 DOI: 10.18632/oncotarget.10905] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/17/2016] [Indexed: 01/18/2023] Open
Abstract
Alzheimer's Disease (AD) is a progressive neurodegenerative disorder characterized by extracellular plaques containing abnormal Amyloid Beta (Aβ) aggregates, intracellular neurofibrillary tangles containing hyperphosphorylated tau protein, microglia-dominated neuroinflammation, and impairments in synaptic plasticity underlying cognitive deficits. Therapeutic strategies for the treatment of AD are currently limited. In this study, we investigated the effects of dietary supplementation of 4% pomegranate extract to a standard chow diet on neuroinflammation, and synaptic plasticity in APPsw/Tg2576 mice brain. Treatment with a custom mixed diet (pellets) containing 4% pomegranate for 15 months ameliorated the loss of synaptic structure proteins, namely PSD-95, Munc18-1, and SNAP25, synaptophysin, phosphorylation of Calcium/Calmodulin Dependent Protein Kinase IIα (p-CaMKIIα/ CaMKIIα), and phosphorylation of Cyclic AMP-Response Element Binding Protein (pCREB/CREB), inhibited neuroinflammatory activity, and enhanced autophagy, and activation of the phophoinositide-3-kinase-Akt-mammalian target of rapamycin signaling pathway. These neuroprotective effects were associated with reduced β-site cleavage of Amyloid Precursor Protein in APPsw/Tg2576 mice. Therefore, long-term supplementation with pomegranates can attenuate AD pathology by reducing inflammation, and altering APP-dependent processes.
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Affiliation(s)
- Nady Braidy
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Musthafa Mohamed Essa
- Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al Khoudh, Oman.,Ageing and Dementia Research Group, Sultan Qaboos University, Al Khoudh, Oman
| | - Anne Poljak
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia.,College of Medicine and Health Sciences, Sultan Qaboos University, Al Khoudh, Oman
| | - Subash Selvaraju
- Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al Khoudh, Oman.,Ageing and Dementia Research Group, Sultan Qaboos University, Al Khoudh, Oman
| | - Samir Al-Adawi
- Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al Khoudh, Oman.,College of Medicine and Health Sciences, Sultan Qaboos University, Al Khoudh, Oman
| | | | | | - Lezanne Ooi
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia
| | - Perminder Sachdev
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia.,Neuropsychiatric Institute, The Prince of Wales Hospital, Sydney, Australia
| | - Gilles J Guillemin
- Neuroinflammation Group, MND and Neurodegenerative Diseases Research Centre, Macquarie University, NSW, Australia
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