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Pérez-Núñez R, González MF, Avalos AM, Leyton L. Impacts of PI3K/protein kinase B pathway activation in reactive astrocytes: from detrimental effects to protective functions. Neural Regen Res 2025; 20:1031-1041. [PMID: 38845231 PMCID: PMC11438337 DOI: 10.4103/nrr.nrr-d-23-01756] [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: 10/24/2023] [Revised: 04/07/2024] [Accepted: 05/06/2024] [Indexed: 07/12/2024] Open
Abstract
Astrocytes are the most abundant type of glial cell in the central nervous system. Upon injury and inflammation, astrocytes become reactive and undergo morphological and functional changes. Depending on their phenotypic classification as A1 or A2, reactive astrocytes contribute to both neurotoxic and neuroprotective responses, respectively. However, this binary classification does not fully capture the diversity of astrocyte responses observed across different diseases and injuries. Transcriptomic analysis has revealed that reactive astrocytes have a complex landscape of gene expression profiles, which emphasizes the heterogeneous nature of their reactivity. Astrocytes actively participate in regulating central nervous system inflammation by interacting with microglia and other cell types, releasing cytokines, and influencing the immune response. The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway is a central player in astrocyte reactivity and impacts various aspects of astrocyte behavior, as evidenced by in silico , in vitro , and in vivo results. In astrocytes, inflammatory cues trigger a cascade of molecular events, where nuclear factor-κB serves as a central mediator of the pro-inflammatory responses. Here, we review the heterogeneity of reactive astrocytes and the molecular mechanisms underlying their activation. We highlight the involvement of various signaling pathways that regulate astrocyte reactivity, including the PI3K/AKT/mammalian target of rapamycin (mTOR), α v β 3 integrin/PI3K/AKT/connexin 43, and Notch/PI3K/AKT pathways. While targeting the inactivation of the PI3K/AKT cellular signaling pathway to control reactive astrocytes and prevent central nervous system damage, evidence suggests that activating this pathway could also yield beneficial outcomes. This dual function of the PI3K/AKT pathway underscores its complexity in astrocyte reactivity and brain function modulation. The review emphasizes the importance of employing astrocyte-exclusive models to understand their functions accurately and these models are essential for clarifying astrocyte behavior. The findings should then be validated using in vivo models to ensure real-life relevance. The review also highlights the significance of PI3K/AKT pathway modulation in preventing central nervous system damage, although further studies are required to fully comprehend its role due to varying factors such as different cell types, astrocyte responses to inflammation, and disease contexts. Specific strategies are clearly necessary to address these variables effectively.
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Affiliation(s)
- Ramón Pérez-Núñez
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Center for Studies on Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Advanced Center for Chronic Diseases (ACCDiS), Faculty of Chemical and Pharmaceutical Sciences & Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - María Fernanda González
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Center for Studies on Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Advanced Center for Chronic Diseases (ACCDiS), Faculty of Chemical and Pharmaceutical Sciences & Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Ana María Avalos
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Lisette Leyton
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Center for Studies on Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Advanced Center for Chronic Diseases (ACCDiS), Faculty of Chemical and Pharmaceutical Sciences & Faculty of Medicine, Universidad de Chile, Santiago, Chile
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2
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Qin H, Zhou L, Haque FT, Martin-Jimenez C, Trang A, Benveniste EN, Wang Q. Diverse signaling mechanisms and heterogeneity of astrocyte reactivity in Alzheimer's disease. J Neurochem 2024; 168:3536-3557. [PMID: 37932959 DOI: 10.1111/jnc.16002] [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: 08/04/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 11/08/2023]
Abstract
Alzheimer's disease (AD) affects various brain cell types, including astrocytes, which are the most abundant cell types in the central nervous system (CNS). Astrocytes not only provide homeostatic support to neurons but also actively regulate synaptic signaling and functions and become reactive in response to CNS insults through diverse signaling pathways including the JAK/STAT, NF-κB, and GPCR-elicited pathways. The advent of new technology for transcriptomic profiling at the single-cell level has led to increasing recognition of the highly versatile nature of reactive astrocytes and the context-dependent specificity of astrocyte reactivity. In AD, reactive astrocytes have long been observed in senile plaques and have recently been suggested to play a role in AD pathogenesis and progression. However, the precise contributions of reactive astrocytes to AD remain elusive, and targeting this complex cell population for AD treatment poses significant challenges. In this review, we summarize the current understanding of astrocyte reactivity and its role in AD, with a particular focus on the signaling pathways that promote astrocyte reactivity and the heterogeneity of reactive astrocytes. Furthermore, we explore potential implications for the development of therapeutics for AD. Our objective is to shed light on the complex involvement of astrocytes in AD and offer insights into potential therapeutic targets and strategies for treating and managing this devastating neurodegenerative disorder.
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Affiliation(s)
- Hongwei Qin
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Lianna Zhou
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Faris T Haque
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Cynthia Martin-Jimenez
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Amy Trang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Etty N Benveniste
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Qin Wang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
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Kostic M, Zivkovic N, Cvetanovic A, Basic J, Stojanovic I. Dissecting the immune response of CD4 + T cells in Alzheimer's disease. Rev Neurosci 2024:revneuro-2024-0090. [PMID: 39238424 DOI: 10.1515/revneuro-2024-0090] [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: 07/04/2024] [Accepted: 08/18/2024] [Indexed: 09/07/2024]
Abstract
The formation of amyloid-β (Aβ) plaques is a neuropathological hallmark of Alzheimer's disease (AD), however, these pathological aggregates can also be found in the brains of cognitively unimpaired elderly population. In that context, individual variations in the Aβ-specific immune response could be key factors that determine the level of Aβ-induced neuroinflammation and thus the propensity to develop AD. CD4+ T cells are the cornerstone of the immune response that coordinate the effector functions of both adaptive and innate immunity. However, despite intensive research efforts, the precise role of these cells during AD pathogenesis is still not fully elucidated. Both pathogenic and beneficial effects have been observed in various animal models of AD, as well as in humans with AD. Although this functional duality of CD4+ T cells in AD can be simply attributed to the vast phenotype heterogeneity of this cell lineage, disease stage-specific effect have also been proposed. Therefore, in this review, we summarized the current understanding of the role of CD4+ T cells in the pathophysiology of AD, from the aspect of their antigen specificity, activation, and phenotype characteristics. Such knowledge is of practical importance as it paves the way for immunomodulation as a therapeutic option for AD treatment, given that currently available therapies have not yielded satisfactory results.
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Affiliation(s)
- Milos Kostic
- Department of Immunology, Medical Faculty of Nis, University of Nis, Blvd. dr Zorana Djindjica 81, Nis, 18000, Serbia
| | - Nikola Zivkovic
- Department of Pathology, Medical Faculty of Nis, University of Nis, Blvd. dr Zorana Djindjica 81, Nis, 18000, Serbia
| | - Ana Cvetanovic
- Department of Oncology, Medical Faculty of Nis, University of Nis, Blvd. dr Zorana Djindjica 81, Nis, 18000, Serbia
| | - Jelena Basic
- Department of Biochemistry, Medical Faculty of Nis, University of Nis, Blvd. dr Zorana Djindjica 81, Nis, 18000, Serbia
| | - Ivana Stojanovic
- Department of Biochemistry, Medical Faculty of Nis, University of Nis, Blvd. dr Zorana Djindjica 81, Nis, 18000, Serbia
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Santiago-Balmaseda A, Aguirre-Orozco A, Valenzuela-Arzeta IE, Villegas-Rojas MM, Pérez-Segura I, Jiménez-Barrios N, Hurtado-Robles E, Rodríguez-Hernández LD, Rivera-German ER, Guerra-Crespo M, Martinez-Fong D, Ledesma-Alonso C, Diaz-Cintra S, Soto-Rojas LO. Neurodegenerative Diseases: Unraveling the Heterogeneity of Astrocytes. Cells 2024; 13:921. [PMID: 38891053 PMCID: PMC11172252 DOI: 10.3390/cells13110921] [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: 05/16/2024] [Accepted: 05/22/2024] [Indexed: 06/20/2024] Open
Abstract
The astrocyte population, around 50% of human brain cells, plays a crucial role in maintaining the overall health and functionality of the central nervous system (CNS). Astrocytes are vital in orchestrating neuronal development by releasing synaptogenic molecules and eliminating excessive synapses. They also modulate neuronal excitability and contribute to CNS homeostasis, promoting neuronal survival by clearance of neurotransmitters, transporting metabolites, and secreting trophic factors. Astrocytes are highly heterogeneous and respond to CNS injuries and diseases through a process known as reactive astrogliosis, which can contribute to both inflammation and its resolution. Recent evidence has revealed remarkable alterations in astrocyte transcriptomes in response to several diseases, identifying at least two distinct phenotypes called A1 or neurotoxic and A2 or neuroprotective astrocytes. However, due to the vast heterogeneity of these cells, it is limited to classify them into only two phenotypes. This review explores the various physiological and pathophysiological roles, potential markers, and pathways that might be activated in different astrocytic phenotypes. Furthermore, we discuss the astrocyte heterogeneity in the main neurodegenerative diseases and identify potential therapeutic strategies. Understanding the underlying mechanisms in the differentiation and imbalance of the astrocytic population will allow the identification of specific biomarkers and timely therapeutic approaches in various neurodegenerative diseases.
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Affiliation(s)
- Alberto Santiago-Balmaseda
- Laboratorio de Patogénesis Molecular, Laboratorio 4 Edificio A4, Carrera Médico Cirujano, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico City 54090, Mexico; (A.S.-B.); (A.A.-O.); (M.M.V.-R.); (I.P.-S.); (E.H.-R.); (L.D.R.-H.); (E.R.R.-G.)
| | - Annai Aguirre-Orozco
- Laboratorio de Patogénesis Molecular, Laboratorio 4 Edificio A4, Carrera Médico Cirujano, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico City 54090, Mexico; (A.S.-B.); (A.A.-O.); (M.M.V.-R.); (I.P.-S.); (E.H.-R.); (L.D.R.-H.); (E.R.R.-G.)
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (I.E.V.-A.); (N.J.-B.); (D.M.-F.)
| | - Irais E. Valenzuela-Arzeta
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (I.E.V.-A.); (N.J.-B.); (D.M.-F.)
| | - Marcos M. Villegas-Rojas
- Laboratorio de Patogénesis Molecular, Laboratorio 4 Edificio A4, Carrera Médico Cirujano, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico City 54090, Mexico; (A.S.-B.); (A.A.-O.); (M.M.V.-R.); (I.P.-S.); (E.H.-R.); (L.D.R.-H.); (E.R.R.-G.)
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de Mexico 11340, Mexico
| | - Isaac Pérez-Segura
- Laboratorio de Patogénesis Molecular, Laboratorio 4 Edificio A4, Carrera Médico Cirujano, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico City 54090, Mexico; (A.S.-B.); (A.A.-O.); (M.M.V.-R.); (I.P.-S.); (E.H.-R.); (L.D.R.-H.); (E.R.R.-G.)
| | - Natalie Jiménez-Barrios
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (I.E.V.-A.); (N.J.-B.); (D.M.-F.)
| | - Ernesto Hurtado-Robles
- Laboratorio de Patogénesis Molecular, Laboratorio 4 Edificio A4, Carrera Médico Cirujano, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico City 54090, Mexico; (A.S.-B.); (A.A.-O.); (M.M.V.-R.); (I.P.-S.); (E.H.-R.); (L.D.R.-H.); (E.R.R.-G.)
| | - Luis Daniel Rodríguez-Hernández
- Laboratorio de Patogénesis Molecular, Laboratorio 4 Edificio A4, Carrera Médico Cirujano, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico City 54090, Mexico; (A.S.-B.); (A.A.-O.); (M.M.V.-R.); (I.P.-S.); (E.H.-R.); (L.D.R.-H.); (E.R.R.-G.)
| | - Erick R. Rivera-German
- Laboratorio de Patogénesis Molecular, Laboratorio 4 Edificio A4, Carrera Médico Cirujano, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico City 54090, Mexico; (A.S.-B.); (A.A.-O.); (M.M.V.-R.); (I.P.-S.); (E.H.-R.); (L.D.R.-H.); (E.R.R.-G.)
| | - Magdalena Guerra-Crespo
- Laboratorio de Medicina Regenerativa, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de Mexico, Mexico City 04510, Mexico;
| | - Daniel Martinez-Fong
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (I.E.V.-A.); (N.J.-B.); (D.M.-F.)
| | - Carlos Ledesma-Alonso
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de Mexico, Querétaro 76230, Mexico;
| | - Sofía Diaz-Cintra
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de Mexico, Querétaro 76230, Mexico;
| | - Luis O. Soto-Rojas
- Laboratorio de Patogénesis Molecular, Laboratorio 4 Edificio A4, Carrera Médico Cirujano, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico City 54090, Mexico; (A.S.-B.); (A.A.-O.); (M.M.V.-R.); (I.P.-S.); (E.H.-R.); (L.D.R.-H.); (E.R.R.-G.)
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Zhang BW, Sun KH, Liu T, Zou W. The Crosstalk Between Immune Cells After Intracerebral Hemorrhage. Neuroscience 2024; 537:93-104. [PMID: 38056621 DOI: 10.1016/j.neuroscience.2023.11.015] [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: 07/14/2023] [Revised: 10/28/2023] [Accepted: 11/15/2023] [Indexed: 12/08/2023]
Abstract
The inflammatory mechanism of intracerebral hemorrhage (ICH) has been widely studied, and it is believed that the regulation of this mechanism is of great significance to the prognosis. In the early stage of the acute phase of ICH, the release of a large number of inflammatory factors around the hematoma can recruit more inflammatory cells to infiltrate the area, further release inflammatory factors, cause an inflammatory cascade reaction, aggravate the volume of cerebral hematoma and edema and further destroy the blood-brain barrier (BBB), according to this, the crosstalk between cells may be of great significance in secondary brain injury (SBI). Because most of the cells recruited are inflammatory immune cells, this paper mainly discusses the cells based on the inflammatory mechanism to discuss their functions after ICH, we found that among the main cells inherent in the brain, glial cells account for the majority, of which microglia are the most widely studied and it can interact with a variety of cells, which is reflected in the literature researches on its pathogenesis and treatment. We believe that exploring multi-mechanism and multi-cell regulated drugs may be the future development trend, and the existing research, the comparison and unification of modeling methods, and the observation of long-term efficacy may be the first problem that researchers need to solve.
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Affiliation(s)
- Bai-Wen Zhang
- The First Clinical Medical College, Heilongjiang University of Chinese Medicine, Harbin 150040, China
| | - Ke-Han Sun
- Rehabilitation Department, Maternal and Child Health Hospital of Xing-an League, Ulanhot City, Inner Mongolia 137400, China
| | - Ting Liu
- Rehabilitation Department, Pengzhou Traditional Chinese Medicine Hospital, Chengdu 611930, China
| | - Wei Zou
- The Third Acupuncture Department, The First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin 150040, China.
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