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Ali MU, Anwar L, Ali MH, Iqubal MK, Iqubal A, Baboota S, Ali J. Signalling Pathways Involved in Microglial Activation in Alzheimer's Disease and Potential Neuroprotective Role of Phytoconstituents. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:819-840. [PMID: 36567300 DOI: 10.2174/1871527322666221223091529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/02/2022] [Accepted: 10/19/2022] [Indexed: 12/27/2022]
Abstract
Alzheimer's disease (AD) is a commonly reported neurodegenerative disorder associated with dementia and cognitive impairment. The pathophysiology of AD comprises Aβ, hyperphosphorylated tau protein formation, abrupt cholinergic cascade, oxidative stress, neuronal apoptosis, and neuroinflammation. Recent findings have established the profound role of immunological dysfunction and microglial activation in the pathogenesis of AD. Microglial activation is a multifactorial cascade encompassing various signalling molecules and pathways such as Nrf2/NLRP3/NF-kB/p38 MAPKs/ GSK-3β. Additionally, deposited Aβ or tau protein triggers microglial activation and accelerates its pathogenesis. Currently, the FDA-approved therapeutic regimens are based on the modulation of the cholinergic system, and recently, one more drug, aducanumab, has been approved by the FDA. On the one hand, these drugs only offer symptomatic relief and not a cure for AD. Additionally, no targetedbased microglial medicines are available for treating and managing AD. On the other hand, various natural products have been explored for the possible anti-Alzheimer effect via targeting microglial activation or different targets of microglial activation. Therefore, the present review focuses on exploring the mechanism and associated signalling related to microglial activation and a detailed description of various natural products that have previously been reported with anti-Alzheimer's effect via mitigation of microglial activation. Additionally, we have discussed the various patents and clinical trials related to managing and treating AD.
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Affiliation(s)
- Mohd Uzair Ali
- School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
| | - Laiba Anwar
- School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
| | - Mohd Humair Ali
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
| | - Mohammad Kashif Iqubal
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
- Sentiss Research Centre, Department of Product Development, Sentiss Pharma Pvt Ltd., Gurugram 122001, India
| | - Ashif Iqubal
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
| | - Sanjula Baboota
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
| | - Javed Ali
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
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p27 kip1 Modulates the Morphology and Phagocytic Activity of Microglia. Int J Mol Sci 2022; 23:ijms231810432. [PMID: 36142366 PMCID: PMC9499407 DOI: 10.3390/ijms231810432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 11/24/2022] Open
Abstract
p27kip1 is a multifunctional protein that promotes cell cycle exit by blocking the activity of cyclin/cyclin-dependent kinase complexes as well as migration and motility via signaling pathways that converge on the actin and microtubule cytoskeleton. Despite the broad characterization of p27kip1 function in neural cells, little is known about its relevance in microglia. Here, we studied the role of p27kip1 in microglia using a combination of in vitro and in situ approaches. While the loss of p27kip1 did not affect microglial density in the cerebral cortex, it altered their morphological complexity in situ. However, despite the presence of p27kip1 in microglial processes, as shown by immunofluorescence in cultured cells, loss of p27kip1 did not change microglial process motility and extension after applying laser-induced brain damage in cortical brain slices. Primary microglia lacking p27kip1 showed increased phagocytic uptake of synaptosomes, while a cell cycle dead variant negatively affected phagocytosis. These findings indicate that p27kip1 plays specific roles in microglia.
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Abstract
Microglia are the resident immune cells of the central nervous system. Microglial progenitors are generated in the yolk sac during the early embryonic stage. Once microglia enter the brain primordium, these cells colonize the structure through migration and proliferation during brain development. Microglia account for a minor population among the total cells that constitute the developing cortex, but they can associate with many surrounding neural lineage cells by extending their filopodia and through their broad migration capacity. Of note, microglia change their distribution in a stage-dependent manner in the developing brain: microglia are homogenously distributed in the pallium in the early and late embryonic stages, whereas these cells are transiently absent from the cortical plate (CP) from embryonic day (E) 15 to E16 and colonize the ventricular zone (VZ), subventricular zone (SVZ), and intermediate zone (IZ). Previous studies have reported that microglia positioned in the VZ/SVZ/IZ play multiple roles in neural lineage cells, such as regulating neurogenesis, cell survival and neuronal circuit formation. In addition to microglial functions in the zones in which microglia are replenished, these cells indirectly contribute to the proper maturation of post-migratory neurons by exiting the CP during the mid-embryonic stage. Overall, microglial time-dependent distributional changes are necessary to provide particular functions that are required in specific regions. This review summarizes recent advances in the understanding of microglial colonization and multifaceted functions in the developing brain, especially focusing on the embryonic stage, and discuss the molecular mechanisms underlying microglial behaviors.
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The Need for New Biomarkers to Assist with Stroke Prevention and Prediction of Post-Stroke Therapy Based on Plasma-Derived Extracellular Vesicles. Biomedicines 2021; 9:biomedicines9091226. [PMID: 34572411 PMCID: PMC8466486 DOI: 10.3390/biomedicines9091226] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/07/2021] [Accepted: 09/13/2021] [Indexed: 12/24/2022] Open
Abstract
The risk of having a stroke event doubles each decade after the age of 55. Therefore, it is of great interest to develop neurorestorative therapies of stroke which occurs mostly in elderly people. However, to date, patients at risk for these sequels of stroke are not duly diagnosed and treated due to the lack of reliable biomarkers. Extracellular vesicles (EVs) are lipid bilayer-delimited particles that are shed by the brain cells and are able to cross the blood–brain barrier and enter the blood stream; thus, they may be used to interrogate molecular and cellular events in the brain damaged area. In this review, we summarize the major molecular and cellular responses of astroglia and neurons to cerebral ischemia and assess their impact on post-stroke recovery and rehabilitation. In particular, we ask if EVs secreted by brain cells are responses to cerebral ischemia, and they may shed new light on the interplay between exosomes-mediated interactions between brain cells and the question of how to exploit it in order to predict the individual course of the disease and to introduce specific preventive or therapeutic strategies. Given these findings, we are left with two options: either to (i) transplant neuronal precursors into the damaged cortical area or (ii) to covert abundantly present proliferating astrocytes in the perilesional area into neurons by using recently developed genetic technologies. However, given the complexity of molecular and cellular responses to cerebral ischemia and our limited capabilities to restore brain structure and function, we are left with only one realistic aim: to invest more in prevention.
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Dong LD, Ma YM, Xu J, Guo YZ, Yang L, Guo FY, Wang MX, Jing L, Zhang JZ. Effect of hyperglycemia on microglial polarization after cerebral ischemia-reperfusion injury in rats. Life Sci 2021; 279:119660. [PMID: 34052292 DOI: 10.1016/j.lfs.2021.119660] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/28/2021] [Accepted: 05/17/2021] [Indexed: 01/11/2023]
Abstract
Hyperglycemia has been shown to aggravate ischemic brain damage, in which the inflammatory reaction induced by hyperglycemia is involved in the worsening of cerebral ischemia-reperfusion injury. However, the role of microglial polarization in hyperglycemia-aggravating cerebral ischemia-reperfusion injury remains unknown. The present study investigated whether diabetic hyperglycemia inhibited or activated microglia, as well as microglial subtypes 1 and 2. Rats were used to establish the diabetic hyperglycemia and middle cerebral artery occlusion (MCAO) model. The markers CD11b, CD16, CD32, CD86, CD206, and Arg1 were used to show M1 or M2 microglia. The results revealed increased neurological deficits, infarct volume, and neural apoptosis in rats with hyperglycemia subjected to MCAO for 30 min and reperfused at 1, 3, and 7 days compared with the normoglycemic rats. Microglia and astrocyte activation and proliferation were inhibited in hyperglycemic rats. Furthermore, M1 microglia polarization was promoted, while that of M2 microglia was inhibited in hyperglycemic rats. These findings suggested that the polarization of M1 and M2 microglia is activated and inhibited, respectively, in hyperglycemic rats and may be involved in the aggravated brain damage caused by ischemia-reperfusion in diabetic hyperglycemia.
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Affiliation(s)
- Ling-di Dong
- Department of Pathology, School of Basic Medical Science, Ningxia Medical University, Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of National Key Laboratory, Yinchuan, Ningxia 750004, China; Department of Dermatology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, China
| | - Yan-Mei Ma
- Department of Pathology, School of Basic Medical Science, Ningxia Medical University, Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of National Key Laboratory, Yinchuan, Ningxia 750004, China
| | - Jie Xu
- Department of Pathology, School of Basic Medical Science, Ningxia Medical University, Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of National Key Laboratory, Yinchuan, Ningxia 750004, China
| | - Yong-Zhen Guo
- Department of Pathology, School of Basic Medical Science, Ningxia Medical University, Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of National Key Laboratory, Yinchuan, Ningxia 750004, China
| | - Lan Yang
- Department of Pathology, School of Basic Medical Science, Ningxia Medical University, Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of National Key Laboratory, Yinchuan, Ningxia 750004, China
| | - Feng-Ying Guo
- Department of Pathology, School of Basic Medical Science, Ningxia Medical University, Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of National Key Laboratory, Yinchuan, Ningxia 750004, China
| | - Min-Xing Wang
- School of Clinical Medical Science, Ningxia Medical University, Yinchuan, Ningxia 750004, China
| | - Li Jing
- Department of Pathology, School of Basic Medical Science, Ningxia Medical University, Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of National Key Laboratory, Yinchuan, Ningxia 750004, China.
| | - Jian-Zhong Zhang
- Department of Pathology, School of Basic Medical Science, Ningxia Medical University, Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of National Key Laboratory, Yinchuan, Ningxia 750004, China.
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