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Sénécal V, Barat C, Tremblay MJ. The delicate balance between neurotoxicity and neuroprotection in the context of HIV-1 infection. Glia 2020; 69:255-280. [PMID: 32910482 DOI: 10.1002/glia.23904] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 08/15/2020] [Accepted: 08/16/2020] [Indexed: 12/17/2022]
Abstract
Human immunodeficiency virus type-1 (HIV-1) causes a spectrum of neurological impairments, termed HIV-associated neurocognitive disorder (HAND), following the infiltration of infected cells into the brain. Even though the implementation of antiretroviral therapy reduced the systemic viral load, the prevalence of HAND remains unchanged and infected patients develop persisting neurological disturbances affecting their quality of life. As a result, HAND have gained importance in basic and clinical researches, warranting the need of developing new adjunctive treatments. Nonetheless, a better understanding of the molecular and cellular mechanisms remains necessary. Several studies consolidated their efforts into elucidating the neurotoxic signaling leading to HAND including the deleterious actions of HIV-1 viral proteins and inflammatory mediators. However, the scope of these studies is not sufficient to address all the complexity related to HAND development. Fewer studies focused on an altered neuroprotective capacity of the brain to respond to HIV-1 infection. Neurotrophic factors are endogenous polyproteins involved in neuronal survival, synaptic plasticity, and neurogenesis. Any defects in the processing or production of these crucial factors might compose a risk factor rendering the brain more vulnerable to neuronal damages. Due to their essential roles, they have been investigated for their diverse interplays with HIV-1 infection. In this review, we present a complete description of the neurotrophic factors involved in HAND. We discuss emerging concepts for their therapeutic applications and summarize the complex mechanisms that down-regulate their production in favor of a neurotoxic environment. For certain factors, we finally address opposing roles that rather lead to increased inflammation.
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Affiliation(s)
- Vincent Sénécal
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du CHU de Québec-Université Laval, Pavillon CHUL, Québec, Quebec, Canada
| | - Corinne Barat
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du CHU de Québec-Université Laval, Pavillon CHUL, Québec, Quebec, Canada
| | - Michel J Tremblay
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du CHU de Québec-Université Laval, Pavillon CHUL, Québec, Quebec, Canada.,Département de Microbiologie-infectiologie et immunologie, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
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Sénécal V, Deblois G, Beauseigle D, Schneider R, Brandenburg J, Newcombe J, Moore CS, Prat A, Antel J, Arbour N. Production of IL-27 in multiple sclerosis lesions by astrocytes and myeloid cells: Modulation of local immune responses. Glia 2015; 64:553-69. [PMID: 26649511 DOI: 10.1002/glia.22948] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/20/2015] [Accepted: 11/17/2015] [Indexed: 01/22/2023]
Abstract
The mechanisms whereby human glial cells modulate local immune responses are not fully understood. Interleukin-27 (IL-27), a pleiotropic cytokine, has been shown to dampen the severity of experimental autoimmune encephalomyelitis, but it is still unresolved whether IL-27 plays a role in the human disease multiple sclerosis (MS). IL-27 contribution to local modulation of immune responses in the brain of MS patients was investigated. The expression of IL-27 subunits (EBI3 and p28) and its cognate receptor IL-27R (the gp130 and TCCR chains) was elevated within post-mortem MS brain lesions compared with normal control brains. Moreover, astrocytes (GFAP(+) cells) as well as microglia and macrophages (Iba1(+) cells) were important sources of IL-27. Brain-infiltrating CD4 and CD8 T lymphocytes expressed the IL-27R specific chain (TCCR) implying that these cells could respond to local IL-27 sources. In primary cultures of human astrocytes inflammatory cytokines increased IL-27 production, whereas myeloid cell inflammatory M1 polarization and inflammatory cytokines enhanced IL-27 expression in microglia and macrophages. Astrocytes in postmortem tissues and in vitro expressed IL-27R. Moreover, IL-27 triggered the phosphorylation of the transcription regulator STAT1, but not STAT3 in human astrocytes; indeed IL-27 up-regulated MHC class I expression on astrocytes in a STAT1-dependent manner. These findings demonstrated that IL-27 and its receptor were elevated in MS lesions and that local IL-27 can modulate immune properties of astrocytes and infiltrating immune cells. Thus, therapeutic strategies targeting IL-27 may influence not only peripheral but also local inflammatory responses within the brain of MS patients.
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Affiliation(s)
- Vincent Sénécal
- Department of Neurosciences, Université De Montréal and CRCHUM Montreal, Quebec, Canada, H2X 0A9
| | - Gabrielle Deblois
- Department of Neurosciences, Université De Montréal and CRCHUM Montreal, Quebec, Canada, H2X 0A9
| | - Diane Beauseigle
- Department of Neurosciences, Université De Montréal and CRCHUM Montreal, Quebec, Canada, H2X 0A9
| | - Raphael Schneider
- Department of Neurosciences, Université De Montréal and CRCHUM Montreal, Quebec, Canada, H2X 0A9
| | - Jonas Brandenburg
- Department of Neurosciences, Université De Montréal and CRCHUM Montreal, Quebec, Canada, H2X 0A9
| | - Jia Newcombe
- NeuroResource, UCL Institute of Neurology, University College London, London, WC1N 1PJ, England
| | - Craig S Moore
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada, H3A 2B4
| | - Alexandre Prat
- Department of Neurosciences, Université De Montréal and CRCHUM Montreal, Quebec, Canada, H2X 0A9
| | - Jack Antel
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada, H3A 2B4
| | - Nathalie Arbour
- Department of Neurosciences, Université De Montréal and CRCHUM Montreal, Quebec, Canada, H2X 0A9
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