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Planas AM. Role of microglia in stroke. Glia 2024; 72:1016-1053. [PMID: 38173414 DOI: 10.1002/glia.24501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/07/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024]
Abstract
Microglia play key roles in the post-ischemic inflammatory response and damaged tissue removal reacting rapidly to the disturbances caused by ischemia and working to restore the lost homeostasis. However, the modified environment, encompassing ionic imbalances, disruption of crucial neuron-microglia interactions, spreading depolarization, and generation of danger signals from necrotic neurons, induce morphological and phenotypic shifts in microglia. This leads them to adopt a proinflammatory profile and heighten their phagocytic activity. From day three post-ischemia, macrophages infiltrate the necrotic core while microglia amass at the periphery. Further, inflammation prompts a metabolic shift favoring glycolysis, the pentose-phosphate shunt, and lipid synthesis. These shifts, combined with phagocytic lipid intake, drive lipid droplet biogenesis, fuel anabolism, and enable microglia proliferation. Proliferating microglia release trophic factors contributing to protection and repair. However, some microglia accumulate lipids persistently and transform into dysfunctional and potentially harmful foam cells. Studies also showed microglia that either display impaired apoptotic cell clearance, or eliminate synapses, viable neurons, or endothelial cells. Yet, it will be essential to elucidate the viability of engulfed cells, the features of the local environment, the extent of tissue damage, and the temporal sequence. Ischemia provides a rich variety of region- and injury-dependent stimuli for microglia, evolving with time and generating distinct microglia phenotypes including those exhibiting proinflammatory or dysfunctional traits and others showing pro-repair features. Accurate profiling of microglia phenotypes, alongside with a more precise understanding of the associated post-ischemic tissue conditions, is a necessary step to serve as the potential foundation for focused interventions in human stroke.
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Affiliation(s)
- Anna M Planas
- Cerebrovascular Research Laboratory, Department of Neuroscience and Experimental Therapeutics, Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain
- Cerebrovascular Diseases, Area of Clinical and Experimental Neuroscience, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS)-Hospital Clínic, Barcelona, Spain
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2
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Murphy DP, Dickson DC, Fatema AN, Carrasco NG, Doyle KP, Trouard TP, Morrison HW. Chronic consequences of ischemic stroke: Profiling brain injury and inflammation in a mouse model with reperfusion. Physiol Rep 2024; 12:e16118. [PMID: 38923318 PMCID: PMC11194179 DOI: 10.14814/phy2.16118] [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: 01/24/2024] [Revised: 06/05/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Stroke is a pervasive and debilitating global health concern, necessitating innovative therapeutic strategies, especially during recovery. While existing literature often focuses on acute interventions, our study addresses the uniqueness of brain tissue during wound healing, emphasizing the chronic phase following the commonly used middle cerebral artery (MCA) occlusion model. Using clinically relevant endpoints in male and female mice such as magnetic resonance imaging (MRI) and plasma neurofilament light (NFL) measurement, along with immunohistochemistry, we describe injury evolution. Our findings document significant alterations in edema, tissue remodeling, and gadolinium leakage through MRI. Plasma NFL concentration remained elevated at 30 days poststroke. Microglia responses are confined to the region adjacent to the injury, rather than continued widespread activation, and boron-dipyrromethene (BODIPY) staining demonstrated the persistent presence of foam cells within the infarct. Additional immunohistochemistry highlighted sustained B and T lymphocyte presence in the poststroke brain. These observations underscore potentially pivotal roles played by chronic inflammation brought on by the lipid-rich brain environment, and chronic blood-brain barrier dysfunction, in the development of secondary neurodegeneration. This study sheds light on the enduring consequences of ischemic stroke in the most used rodent stroke model and provides valuable insights for future research, clinical strategies, and therapeutic development.
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Affiliation(s)
- Devin P. Murphy
- Department of Biomedical Engineering, College of EngineeringUniversity of ArizonaTucsonArizonaUSA
| | | | - Arisha N. Fatema
- Department of Biomedical Engineering, College of EngineeringUniversity of ArizonaTucsonArizonaUSA
| | | | - Kristian P. Doyle
- Department of Immunology, College of MedicineUniversity of ArizonaTucsonArizonaUSA
| | - Theodore P. Trouard
- Department of Biomedical Engineering, College of EngineeringUniversity of ArizonaTucsonArizonaUSA
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Kuang H, Zhu X, Chen H, Tang H, Zhao H. The immunomodulatory mechanism of acupuncture treatment for ischemic stroke: research progress, prospects, and future direction. Front Immunol 2024; 15:1319863. [PMID: 38756772 PMCID: PMC11096548 DOI: 10.3389/fimmu.2024.1319863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 04/03/2024] [Indexed: 05/18/2024] Open
Abstract
Ischemic stroke (IS) is one of the leading causes of death and disability. Complicated mechanisms are involved in the pathogenesis of IS. Immunomodulatory mechanisms are crucial to IS. Acupuncture is a traditional non-drug treatment that has been extensively used to treat IS. The exploration of neuroimmune modulation will broaden the understanding of the mechanisms underlying acupuncture treatment. This review summarizes the immune response of immune cells, immune cytokines, and immune organs after an IS. The immunomodulatory mechanisms of acupuncture treatment on the central nervous system and peripheral immunity, as well as the factors that influence the effects of acupuncture treatment, were summarized. We suggest prospects and future directions for research on immunomodulatory mechanisms of acupuncture treatment for IS based on current progress, and we hope that these will provide inspiration for researchers. Additionally, acupuncture has shown favorable outcomes in the treatment of immune-based nervous system diseases, generating new directions for research on possible targets and treatments for immune-based nervous system diseases.
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Affiliation(s)
- Hongjun Kuang
- Department of Acupuncture and Moxibustion, Shenzhen Luohu Hospital of Traditional Chinese Medicine (Shenzhen Hospital of Shanghai University of Traditional Chinese Medicine), Shenzhen, China
| | - Xinzhou Zhu
- The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Huan Chen
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Science, Beijing, China
| | - Han Tang
- Department of Acupuncture and Moxibustion, Shenzhen Luohu Hospital of Traditional Chinese Medicine (Shenzhen Hospital of Shanghai University of Traditional Chinese Medicine), Shenzhen, China
| | - Hong Zhao
- Department of Acupuncture and Moxibustion, Shenzhen Luohu Hospital of Traditional Chinese Medicine (Shenzhen Hospital of Shanghai University of Traditional Chinese Medicine), Shenzhen, China
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Loppi SH, Tavera-Garcia MA, Scholpa NE, Maiyo BK, Becktel DA, Morrison HW, Schnellmann RG, Doyle KP. Boosting Mitochondrial Biogenesis Diminishes Foam Cell Formation in the Post-Stroke Brain. Int J Mol Sci 2023; 24:16632. [PMID: 38068955 PMCID: PMC10706318 DOI: 10.3390/ijms242316632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/16/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Following ischemic stroke, the degradation of myelin and other cellular membranes surpasses the lipid-processing capabilities of resident microglia and infiltrating macrophages. This imbalance leads to foam cell formation in the infarct and areas of secondary neurodegeneration, instigating sustained inflammation and furthering neurological damage. Given that mitochondria are the primary sites of fatty acid metabolism, augmenting mitochondrial biogenesis (MB) may enhance lipid processing, curtailing foam cell formation and post-stroke chronic inflammation. Previous studies have shown that the pharmacological activation of the β2-adrenergic receptor (β2-AR) stimulates MB. Consequently, our study sought to discern the effects of intensified β2-AR signaling on MB, the processing of brain lipid debris, and neurological outcome using a mouse stroke model. To achieve this goal, aged mice were treated with formoterol, a long-acting β2-AR agonist, daily for two and eight weeks following stroke. Formoterol increased MB in the infarct region, modified fatty acid metabolism, and reduced foam cell formation. However, it did not reduce markers of post-stroke neurodegeneration or improve recovery. Although our findings indicate that enhancing MB in myeloid cells can aid in the processing of brain lipid debris after stroke, it is important to note that boosting MB alone may not be sufficient to significantly impact stroke recovery.
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Affiliation(s)
- Sanna H. Loppi
- Department of Immunobiology, College of Medicine, University of Arizona, Tucson, AZ 85719, USA; (S.H.L.); (M.A.T.-G.); (B.K.M.); (D.A.B.)
| | - Marco A. Tavera-Garcia
- Department of Immunobiology, College of Medicine, University of Arizona, Tucson, AZ 85719, USA; (S.H.L.); (M.A.T.-G.); (B.K.M.); (D.A.B.)
| | - Natalie E. Scholpa
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85719, USA; (N.E.S.); (R.G.S.)
| | - Boaz K. Maiyo
- Department of Immunobiology, College of Medicine, University of Arizona, Tucson, AZ 85719, USA; (S.H.L.); (M.A.T.-G.); (B.K.M.); (D.A.B.)
| | - Danielle A. Becktel
- Department of Immunobiology, College of Medicine, University of Arizona, Tucson, AZ 85719, USA; (S.H.L.); (M.A.T.-G.); (B.K.M.); (D.A.B.)
| | | | - Rick G. Schnellmann
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85719, USA; (N.E.S.); (R.G.S.)
- BIO5 Institute, College of Medicine, University of Arizona, Tucson, AZ 85719, USA
- R. Ken Coit Center for Longevity and Neurotherapeutics, College of Pharmacy, University of Arizona, Tucson, AZ 85719, USA
| | - Kristian P. Doyle
- Department of Immunobiology, College of Medicine, University of Arizona, Tucson, AZ 85719, USA; (S.H.L.); (M.A.T.-G.); (B.K.M.); (D.A.B.)
- BIO5 Institute, College of Medicine, University of Arizona, Tucson, AZ 85719, USA
- Department of Neurology, College of Medicine, University of Arizona, Tucson, AZ 85719, USA
- Arizona Center on Aging, College of Medicine, University of Arizona, Tucson, AZ 85719, USA
- Department of Psychology, College of Medicine, University of Arizona, Tucson, AZ 85719, USA
- Department of Neurosurgery, College of Medicine, University of Arizona, Tucson, AZ 85719, USA
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Shi Y, Stowe AM, Hu X. The role of immune cells in brain injuries and diseases. Neurobiol Dis 2023; 188:106340. [PMID: 37913833 DOI: 10.1016/j.nbd.2023.106340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023] Open
Affiliation(s)
- Yejie Shi
- Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Ann M Stowe
- Department of Neurology, College of Medicine, University of Kentucky, Lexington, KY, USA.
| | - Xiaoming Hu
- Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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