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Davidson TL, Stevenson RJ. Vulnerability of the Hippocampus to Insults: Links to Blood-Brain Barrier Dysfunction. Int J Mol Sci 2024; 25:1991. [PMID: 38396670 PMCID: PMC10888241 DOI: 10.3390/ijms25041991] [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: 01/03/2024] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
The hippocampus is a critical brain substrate for learning and memory; events that harm the hippocampus can seriously impair mental and behavioral functioning. Hippocampal pathophysiologies have been identified as potential causes and effects of a remarkably diverse array of medical diseases, psychological disorders, and environmental sources of damage. It may be that the hippocampus is more vulnerable than other brain areas to insults that are related to these conditions. One purpose of this review is to assess the vulnerability of the hippocampus to the most prevalent types of insults in multiple biomedical domains (i.e., neuroactive pathogens, neurotoxins, neurological conditions, trauma, aging, neurodegenerative disease, acquired brain injury, mental health conditions, endocrine disorders, developmental disabilities, nutrition) and to evaluate whether these insults affect the hippocampus first and more prominently compared to other brain loci. A second purpose is to consider the role of hippocampal blood-brain barrier (BBB) breakdown in either causing or worsening the harmful effects of each insult. Recent research suggests that the hippocampal BBB is more fragile compared to other brain areas and may also be more prone to the disruption of the transport mechanisms that act to maintain the internal milieu. Moreover, a compromised BBB could be a factor that is common to many different types of insults. Our analysis indicates that the hippocampus is more vulnerable to insults compared to other parts of the brain, and that developing interventions that protect the hippocampal BBB may help to prevent or ameliorate the harmful effects of many insults on memory and cognition.
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Affiliation(s)
- Terry L. Davidson
- Department of Neuroscience, Center for Neuroscience and Behavior, American University, 4400 Massachusetts Avenue, NW, Washington, DC 20016, USA
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Hussain MS, Gupta G, Samuel VP, Almalki WH, Kazmi I, Alzarea SI, Saleem S, Khan R, Altwaijry N, Patel S, Patel A, Singh SK, Dua K. Immunopathology of herpes simplex virus-associated neuroinflammation: Unveiling the mysteries. Rev Med Virol 2024; 34:e2491. [PMID: 37985599 DOI: 10.1002/rmv.2491] [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: 10/04/2023] [Revised: 10/21/2023] [Accepted: 11/03/2023] [Indexed: 11/22/2023]
Abstract
The immunopathology of herpes simplex virus (HSV)-associated neuroinflammation is a captivating and intricate field of study within the scientific community. HSV, renowned for its latent infection capability, gives rise to a spectrum of neurological expressions, ranging from mild symptoms to severe encephalitis. The enigmatic interplay between the virus and the host's immune responses profoundly shapes the outcome of these infections. This review delves into the multifaceted immune reactions triggered by HSV within neural tissues, intricately encompassing the interplay between innate and adaptive immunity. Furthermore, this analysis delves into the delicate equilibrium between immune defence and the potential for immunopathology-induced neural damage. It meticulously dissects the roles of diverse immune cells, cytokines, and chemokines, unravelling the intricacies of neuroinflammation modulation and its subsequent effects. By exploring HSV's immune manipulation and exploitation mechanisms, this review endeavours to unveil the enigmas surrounding the immunopathology of HSV-associated neuroinflammation. This comprehensive understanding enhances our grasp of viral pathogenesis and holds promise for pioneering therapeutic strategies designed to mitigate the neurological ramifications of HSV infections.
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Affiliation(s)
- Md Sadique Hussain
- School of Pharmaceutical Sciences, Jaipur National University, Jaipur, Rajasthan, India
| | - Gaurav Gupta
- Centre for Global Health Research, Saveetha Medical College, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Kuthambakkam, India
- School of Pharmacy, Graphic Era Hill University, Dehradun, India
- School of Pharmacy, Suresh Gyan Vihar University, Jaipur, India
| | - Vijaya Paul Samuel
- Department of Anatomy, RAK College of Medicine, RAK Medical and Health Sciences, Ras Al Khaimah, United Arab Emirates
| | - Waleed Hassan Almalki
- Department of Pharmacology, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Imran Kazmi
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sami I Alzarea
- Department of Pharmacology, College of Pharmacy, Jouf University, Sakaka, Al-Jouf, Saudi Arabia
| | - Shakir Saleem
- Department of Public Health, College of Health Sciences, Saudi Electronic University, Riyadh, Saudi Arabia
| | - Ruqaiyah Khan
- Department of Basic Health Sciences, Deanship of Preparatory Year for the Health Colleges, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Najla Altwaijry
- Department of Pharmaceutical Sciences, College of Pharmacy, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Samir Patel
- Department of Pharmaceutical Chemistry and Analysis, Ramanbhai Patel College of Pharmacy, Charotar University of Science and Technology, Changa, Gujarat, India
| | - Archita Patel
- Department of Pharmaceutical Chemistry and Analysis, Ramanbhai Patel College of Pharmacy, Charotar University of Science and Technology, Changa, Gujarat, India
| | - Sachin Kumar Singh
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab, India
- Faculty of Health, Australian Research Centre in Complementary and Integrative Medicine, University of Technology Sydney, Ultimo, Australia
| | - Kamal Dua
- Faculty of Health, Australian Research Centre in Complementary and Integrative Medicine, University of Technology Sydney, Ultimo, Australia
- Discipline of Pharmacy, Graduate School of Health, University of Technology Sydney, Broadway, New South Wales, Australia
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Doshi H, Spengler K, Godbole A, Gee YS, Baell J, Oakhill JS, Henke A, Heller R. AMPK protects endothelial cells against HSV-1 replication via inhibition of mTORC1 and ACC1. Microbiol Spectr 2023; 11:e0041723. [PMID: 37702499 PMCID: PMC10580915 DOI: 10.1128/spectrum.00417-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 07/06/2023] [Indexed: 09/14/2023] Open
Abstract
Herpes simplex virus type 1 (HSV-1) is a widespread contagious pathogen, mostly causing mild symptoms on the mucosal entry side. However, systemic distribution, in particular upon reactivation of the virus in immunocompromised patients, may trigger an innate immune response and induce damage of organs. In these conditions, HSV-1 may infect vascular endothelial cells, but little is known about the regulation of HSV-1 replication and possible defense mechanisms in these cells. The current study addresses the question of whether the host cell protein AMP-activated protein kinase (AMPK), an important metabolic sensor, can control HSV-1 replication in endothelial cells. We show that downregulation of the catalytic subunits AMPKα1 and/or AMPKα2 increased HSV-1 replication as monitored by TCID50 titrations, while a potent AMPK agonist, MK-8722, strongly inhibited it. MK-8722 induced a persistent phosphorylation of the AMPK downstream targets acetyl-CoA carboxylase (ACC) and the rapamycin-sensitive adaptor protein of mTOR (Raptor) and, related to this, impairment of ACC1-mediated lipid synthesis and the mechanistic target of the rapamycin complex-1 (mTORC1) pathway. Since blockade of mTOR by Torin-2 as well as downregulation of ACC1 by siRNA also decreased HSV-1 replication, MK-8722 is likely to exert its anti-viral effect via mTORC1 and ACC1 inhibition. Importantly, MK-8722 was able to reduce virus replication even when added after HSV-1. Together, our data highlight the importance of endothelial cells as host cells for HSV-1 replication upon systemic infection and identify AMPK, a metabolic host cell protein, as a potential target for antiviral strategies against HSV-1 infection and its severe consequences. IMPORTANCE Herpes simplex virus type 1 (HSV-1) is a common pathogen that causes blisters or cold sores in humans. It remains latent in infected individuals and can be reactivated multiple times. In adverse conditions, for instance, in immunocompromised patients, HSV-1 can lead to serious complications such as encephalitis, meningitis, or blindness. In these situations, infection of endothelial cells lining the surface of blood vessels may contribute to the manifestation of disease. Here, we describe the role of AMP-activated protein kinase (AMPK), a potent regulator of cellular energy metabolism, in HSV-1 replication in endothelial cells. While downregulation of AMPK potentiates HSV-1 replication, pharmacological AMPK activation inhibits it by limiting the availability of required host cell macromolecules such as proteins or fatty acids. These data highlight the role of metabolic host cell proteins as antiviral targets and reveal activation of endothelial AMPK as a potential strategy to protect from severe consequences of HSV-1 infection.
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Affiliation(s)
- Heena Doshi
- Institute for Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany
| | - Katrin Spengler
- Institute for Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany
| | - Amod Godbole
- Institute for Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany
| | - Yi Sing Gee
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Jonathan Baell
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, China
| | - Jonathan S. Oakhill
- Metabolic Signaling Laboratory, St. Vincent’s Institute of Medical Research, Fitzroy, Victoria, Australia
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, Australia
| | - Andreas Henke
- Section of Experimental Virology, Institute of Medical Microbiology, Jena University Hospital, Jena, Germany
| | - Regine Heller
- Institute for Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany
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Abstract
PURPOSE OF REVIEW HSV is the most frequently identified cause of infectious encephalitis, in Western countries. This article is an update on the topic based on a review of recent studies from 2017 to 2018. RECENT FINDINGS Acyclovir is still the first line treatment, and no new drugs are currently available for clinical use. The major considerations for HSV encephalitis are as follows: point one, clinical evaluation remains the most important factor, as though CSF HSV PCR has a good sensitivity, in a small proportion of patients the initial testing might be negative. MRI brain is the first line imaging test, and mesial temporal lobe involvement and other typical findings are important for diagnosis; point 2, there should be emphasis on sequela, short-term, and long-term outcomes, and not just case fatality rated in future studies and clinical management. Auto-immune encephalitis can be triggered by HSV, and should be considered in patients who are not responding to treatment; point 3, future studies should be on better management of sequela, and better treatment regimens including those targeting the immune response. SUMMARY Autoimmune encephalitis is a clearly identified complication of HSV encephalitis. Inflammatory mechanisms are linked to the clinical presentation as well as severity and poor outcome. Initial corticosteroid therapy has to be evaluated in order to prevent complications.
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