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Melanis K, Stefanou MI, Themistoklis KM, Papasilekas T. mTOR pathway - a potential therapeutic target in stroke. Ther Adv Neurol Disord 2023; 16:17562864231187770. [PMID: 37576547 PMCID: PMC10413897 DOI: 10.1177/17562864231187770] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 06/27/2023] [Indexed: 08/15/2023] Open
Abstract
Stroke is ranked as the second leading cause of death worldwide and a major cause of long-term disability. A potential therapeutic target that could offer favorable outcomes in stroke is the mammalian target of rapamycin (mTOR) pathway. mTOR is a serine/threonine kinase that composes two protein complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), and is regulated by other proteins such as the tuberous sclerosis complex. Through a significant number of signaling pathways, the mTOR pathway can modulate the processes of post-ischemic inflammation and autophagy, both of which play an integral part in the pathophysiological cascade of stroke. Promoting or inhibiting such processes under ischemic conditions can lead to apoptosis or instead sustained viability of neurons. The purpose of this review is to examine the pathophysiological role of mTOR in acute ischemic stroke, while highlighting promising neuroprotective agents such as hamartin for therapeutic modulation of this pathway. The therapeutic potential of mTOR is also discussed, with emphasis on implicated molecules and pathway steps that warrant further elucidation in order for their neuroprotective properties to be efficiently tested in future clinical trials.
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Affiliation(s)
- Konstantinos Melanis
- Second Department of Neurology, School of Medicine and ‘Attikon’ University Hospital, National and Kapodistrian University of Athens, Rimini 1 Chaidari, Athens 12462, Greece
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Maria-Ioanna Stefanou
- Second Department of Neurology, School of Medicine and ‘Attikon’ University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Konstantinos M. Themistoklis
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Department of Neurosurgery, ‘Korgialenio, Benakio, H.R.C’. General Hospital of Athens, Athens, Greece
| | - Themistoklis Papasilekas
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Department of Neurosurgery, ‘Korgialenio, Benakio, H.R.C’. General Hospital of Athens, Athens, Greece
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Hu X, Zhang Y, Gu C, Wu R, Yao Y, Gao F, Luo L, Zhang Y. TMAO promotes dementia progression by mediating the PI3K/Akt/mTOR pathway. Tissue Cell 2023; 81:102034. [PMID: 36753814 DOI: 10.1016/j.tice.2023.102034] [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] [Received: 10/08/2022] [Revised: 01/05/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023]
Abstract
BACKGROUND Dementia poses a serious threat to the daily and social abilities of patients, and trimethylamine-N-oxide (TMAO) is a metabolite of the gut microbiota involved in regulating the inflammatory response. However, the role of TMAO in dementia needs further investigation. This study aimed to investigate the effects and possible mechanisms of TMAO on dementia, which may provide ideas for the treatment of dementia. MATERIALS AND METHODS Dementia mice were induced by D-galactose + AlCl3, and the changes in learning memory capacity, histopathology, inflammatory factors, and PI3K/Akt/mTOR in mice treated with TMAO were analyzed to determine the mechanism of TMAO action on dementia. In addition, the effect of TMAO+PI3K inhibitor treatment on mice was also analyzed to further determine the mechanism of TMAO effect on dementia. RESULTS The results revealed that the dementia group had significantly higher TMAO levels and a significant hippocampal injury and inflammatory response. TMAO treatment promoted hippocampal injury and promoted the level of inflammatory cytokines. Further study of PI3K/Akt/mTOR signaling pathway showed that the expression of p-PI3K, p-Akt, and p-mTOR was significantly increased in the dementia group, and it was more obvious after TMAO treatment. And hippocampal injury, inflammatory response, and increase of p-PI3K, p-Akt, p-mTOR were reversed by TMAO+PI3K inhibitor. CONCLUSIONS This study determined that TMAO promotes dementia through the PI3K/Akt/mTOR signaling pathway, suggesting that TMAO may be a potential target for dementia.
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Affiliation(s)
- Xiaojuan Hu
- Department of Neurology, Gansu Provincial People´s Hospital, Lanzhou, China.
| | - Yamin Zhang
- Department of Neurology, Gansu Provincial People´s Hospital, Lanzhou, China.
| | - Cheng Gu
- Department of Neurology, Gansu Provincial People´s Hospital, Lanzhou, China.
| | - Ruipeng Wu
- Department of Neurology, Gansu Provincial People´s Hospital, Lanzhou, China.
| | - Yuping Yao
- Department of Neurology, Gansu Provincial People´s Hospital, Lanzhou, China.
| | - Fulin Gao
- Department of Neurology, Gansu Provincial People´s Hospital, Lanzhou, China.
| | - Lulu Luo
- Department of Neurology, Gansu Provincial People´s Hospital, Lanzhou, China.
| | - Yi Zhang
- Department of Neurology, Gansu Provincial People´s Hospital, Lanzhou, China.
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Zhou J, Zhang P, Zhang B, Kong Y. White Matter Damage in Alzheimer's Disease: Contribution of Oligodendrocytes. Curr Alzheimer Res 2022; 19:CAR-EPUB-127137. [PMID: 36281858 PMCID: PMC9982194 DOI: 10.2174/1567205020666221021115321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/15/2022] [Accepted: 09/23/2022] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disease, seriously influencing the quality of life and is a global health problem. Many factors affect the onset and development of AD, but specific mechanisms underlying the disease are unclear. Most studies investigating AD have focused on neurons and the gray matter in the central nervous system (CNS) but have not led to effective treatments. Recently, an increasing number of studies have focused on the white matter (WM). Magnetic resonance imaging and pathology studies have shown different degrees of WM abnormality during the progression of AD. Myelin sheaths, the main component of WM in the CNS, wrap and insulate axons to ensure conduction of the rapid action potential and axonal integrity. WM damage is characterized by progressive degeneration of axons, oligodendrocytes (OLs), and myelin in one or more areas of the CNS. The contributions of OLs to AD progression have, until recently, been largely overlooked. OLs are integral to myelin production, and the proliferation and differentiation of OLs, an early characteristic of AD, provide a promising target for preclinical diagnosis and treatment. However, despite some progress, the key mechanisms underlying the contributions of OLs to AD remain unclear. Given the heavy burden of medical treatment, a better understanding of the pathophysiological mechanisms underlying AD is vital. This review comprehensively summarize the results on WM abnormalities in AD and explores the relationship between OL progenitor cells and the pathogenesis of AD. Finally, the underlying molecular mechanisms and potential future research directions are discussed.
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Affiliation(s)
- Jinyu Zhou
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing-400042, China
| | - Peng Zhang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing-400010, China
| | - Bo Zhang
- Department of Basic Medicine, Chongqing Medical and Pharmaceutical College, Chongqing-401331, China
| | - Yuhan Kong
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing-400042, China
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Villa-González M, Martín-López G, Pérez-Álvarez MJ. Dysregulation of mTOR Signaling after Brain Ischemia. Int J Mol Sci 2022; 23:ijms23052814. [PMID: 35269956 PMCID: PMC8911477 DOI: 10.3390/ijms23052814] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/28/2022] [Accepted: 03/01/2022] [Indexed: 02/04/2023] Open
Abstract
In this review, we provide recent data on the role of mTOR kinase in the brain under physiological conditions and after damage, with a particular focus on cerebral ischemia. We cover the upstream and downstream pathways that regulate the activation state of mTOR complexes. Furthermore, we summarize recent advances in our understanding of mTORC1 and mTORC2 status in ischemia–hypoxia at tissue and cellular levels and analyze the existing evidence related to two types of neural cells, namely glia and neurons. Finally, we discuss the potential use of mTORC1 and mTORC2 as therapeutic targets after stroke.
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Affiliation(s)
- Mario Villa-González
- Departamento de Biología (Fisiología Animal), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.V.-G.); (G.M.-L.)
- Centro de Biología Molecular “Severo Ochoa” (CBMSO), Universidad Autónoma de Madrid/CSIC, 28049 Madrid, Spain
| | - Gerardo Martín-López
- Departamento de Biología (Fisiología Animal), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.V.-G.); (G.M.-L.)
| | - María José Pérez-Álvarez
- Departamento de Biología (Fisiología Animal), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.V.-G.); (G.M.-L.)
- Centro de Biología Molecular “Severo Ochoa” (CBMSO), Universidad Autónoma de Madrid/CSIC, 28049 Madrid, Spain
- Correspondence: ; Tel.: +34-91-497-2819
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Yu H, Shi J, Lin Y, Zhang Y, Luo Q, Huang S, Wang S, Wei J, Huang J, Li C, Ji L. Icariin Ameliorates Alzheimer's Disease Pathology by Alleviating Myelin Injury in 3 × Tg-AD Mice. Neurochem Res 2022; 47:1049-1059. [PMID: 35037164 DOI: 10.1007/s11064-021-03507-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 11/09/2021] [Accepted: 12/07/2021] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease characterized by excessive deposition of β amyloid (Aβ), hyperphosphorylation of tau protein, and neuronal cell death. Recent studies have shown that myelin cell damage, which leads to cognitive dysfunction, occurs before AD-related pathological changes. Here, we examine the effect of icariin (ICA), a prenylated flavonol glycoside, in improving cognitive function in AD model mice. ICA has been reported to exhibit cardiovascular protective functions and antiaging effects. In this study, we used 3 × Tg-AD mice as an AD model. The Morris water maze and Y maze tests were performed to assess the learning and memory of the mice. Immunofluorescence analysis of Aβ1-42 deposition and myelin basic protein (MBP) expression in the mouse hippocampus was performed. Tau protein phosphorylation and MBP protein expression in the hippocampus were further analyzed by Western blotting. Myelin damage in the mouse optic nerve was evaluated by electron microscopy, and LFB staining was performed to assess myelin morphology in the mouse corpus callosum. MBP, Mpp5, and Egr2 transcript levels were quantified by qPCR. We observed that ICA treatment improved the learning and memory of 3 × Tg-AD mice and reduced Aβ deposition and tau protein phosphorylation in the hippocampus. Moreover, this treatment protocol increased myelin-related gene expression and reduced myelin damage.
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Affiliation(s)
- Hongxia Yu
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Jianhong Shi
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Yiyou Lin
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Yehui Zhang
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Qihang Luo
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Suo Huang
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Sichen Wang
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Jiale Wei
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Junhao Huang
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Changyu Li
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China.
| | - Liting Ji
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China.
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Zheng M, Liu Z, Mana L, Qin G, Huang S, Gong Z, Tian M, He Y, Wang P. Shenzhiling oral liquid protects the myelin sheath against Alzheimer's disease through the PI3K/Akt-mTOR pathway. JOURNAL OF ETHNOPHARMACOLOGY 2021; 278:114264. [PMID: 34082015 DOI: 10.1016/j.jep.2021.114264] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 05/22/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Shenzhiling oral liquid (SZL), a traditional Chinese medicine (TCM) compound, is firstly approved by the Chinese Food and Drug Administration (CFDA) for the treatment of mild to moderate Alzheimer's disease (AD). SZL is composed of ten Chinese herbs, and the precise therapy mechanism of its action to AD is far from fully understood. AIM OF THE STUDY The purpose of this study was to observe whether SZL is an effective therapy for amyloid-beta (Aβ)-induced myelin sheath and oligodendrocytes impairments. Notably, the primary aim was to elucidate whether and through what underlying mechanism SZL protects the myelin sheath through the PI3K/Akt-mTOR signaling pathway in Aβ42-induced OLN-93 oligodendrocytes in vitro. MATERIALS AND METHODS APP/PS1 mice were treated with SZL or donepezil continuously for three months, and Aβ42-induced oligodendrocyte OLN-93 cells mimicking AD pathogenesis of myelin sheath impairments were incubated with SZL-containing serum or with donepezil. LC-MS/MS was used to analysis the active components of SZL and SZL-containing serum. The Y maze test was administered after 3 months of treatment, and the hippocampal tissues of the APP/PS1 mice were then harvested for observation of myelin sheath and oligodendrocyte morphology. Cell viability and toxicity were assessed using CCK-8 and lactate dehydrogenase (LDH) release assays, and flow cytometry was used to measure cell apoptosis. The expression of the myelin proteins MBP, PLP, and MAG and that of Aβ42 and Aβ40 in the hippocampi of APP/PS1 mice were examined after SZL treatment. Simultaneously, the expression of p-PI3K, PI3K, p-Akt, Akt, p-mTOR, and mTOR were also examined. The expression of proteins, including CNPase, Olig2, NKX2.2, MBP, PLP, MAG, MOG, p-PI3K, PI3K, p-Akt, Akt, p-mTOR, and mTOR, was determined by immunofluorescence and Western blot, and the corresponding gene expression was evaluated by qPCR in Aβ42-induced OLN-93 oligodendrocytes. RESULTS LC-MS/MS detected a total of 126 active compounds in SZL-containing serum, including terpenoids, flavones, phenols, phenylpropanoids and phenolic acids. SZL treatment significantly improved memory and cognition in APP/PS1 mice and decreased the G-ratio of myelin sheath, alleviated myelin sheath and oligodendrocyte impairments by decreasing Aβ42 and Aβ40 accumulation and increasing the expression of myelin proteins MBP, PLP, MAG, and PI3K/Akt-mTOR signaling pathway associated protein in the hippocampi of APP/PS1 mice. SZL-containing serum also significantly reversed the OLN-93 cell injury induced by Aβ42 by increasing cell viability and enhanced the expression of MBP, PLP, MAG, and MOG. Meanwhile, SZL-containing serum facilitated the maturation and differentiation of oligodendrocytes in Aβ42-induced OLN-93 cells by heightening the expression of CNPase, Olig2 and NKX2.2. SZL-containing serum treatment also fostered the expression of p-PI3K, PI3K, p-Akt, Akt, p-mTOR, and mTOR, indicating an activating PI3K/Akt-mTOR signaling pathway in OLN-93 cells. Furthermore, the effects of SZL on myelin proteins, p-Akt, and p-mTOR were clearly inhibited by LY294002 and/or rapamycin, antagonists of PI3K and m-TOR, respectively. CONCLUSIONS Our findings indicate that SZL exhibits a neuroprotective effect on the myelin sheath by promoting the expression of myelin proteins during AD, and its mechanism of action is closely related to the activation of the PI3K/Akt-mTOR signaling pathway.
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Affiliation(s)
- Mingcui Zheng
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, 100700, China; Key Laboratory of Pharmacology Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, 100700, China.
| | - Zhenhong Liu
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, 100700, China; Key Laboratory of Pharmacology Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, 100700, China; Institute for Brain Disorders, Beijing University of Chinese Medicine (BUCM), Beijing, 100029, China.
| | - Lulu Mana
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, 100700, China; Key Laboratory of Pharmacology Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, 100700, China; Xinjiang Medical University, Urumqi, 830011, China.
| | - Gaofeng Qin
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, 100700, China; Key Laboratory of Pharmacology Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, 100700, China.
| | - Shuaiyang Huang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, 100700, China; Key Laboratory of Pharmacology Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, 100700, China.
| | - Zhuoyan Gong
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, 100700, China; Key Laboratory of Pharmacology Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, 100700, China.
| | - Meijing Tian
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, 100700, China; Key Laboratory of Pharmacology Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, 100700, China.
| | - Yannan He
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, 100700, China; Key Laboratory of Pharmacology Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, 100700, China.
| | - Pengwen Wang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, 100700, China; Key Laboratory of Pharmacology Dongzhimen Hospital (BUCM), State Administration of Traditional Chinese Medicine, Beijing, 100700, China.
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