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Systemic administration of orexin A ameliorates established experimental autoimmune encephalomyelitis by diminishing neuroinflammation.

ABSTRACT: BACKGROUND:Orexins (hypocretins, Hcrt) A and B are GPCR-binding hypothalamic neuropeptides known to regulate sleep/wake states and feeding behavior. A few studies have shown that orexin A exhibits anti-inflammatory and neuroprotective properties, suggesting that it might provide therapeutic effects in inflammatory and neurodegenerative diseases like multiple sclerosis (MS). In MS, encephalitogenic Th1 and Th17 cells trigger an inflammatory response in the CNS destroying the myelin sheath. Here, we investigated the effects of peripheral orexin A administration to mice undergoing experimental autoimmune encephalomyelitis (EAE), a widely used model of MS. METHODS:Mice were subcutaneously immunized with myelin oligodendrocyte glycoprotein peptide (MOG)35-55 in CFA. Mice were treated intraperitoneally for five consecutive days with either PBS or 300 ?g of orexin A starting at a moderate EAE score. Molecular, cellular, and histological analysis were performed by real-time PCR, ELISA, flow cytometry, and immunofluorescence. RESULTS:Orexin A strongly ameliorated ongoing EAE, limiting the infiltration of pathogenic CD4+ T lymphocytes, and diminishing chemokine (MCP-1/CCL2 and IP-10/CXCL10) and cytokine (IFN-? (Th1), IL-17 (Th17), TNF-?, IL-10, and TGF-?) expressions in the CNS. Moreover, orexin A treatment was neuroprotective, decreasing demyelination, astrogliosis, and microglial activation. Despite its strong local therapeutic effects, orexin A did not impair peripheral draining lymph node cell proliferation and Th1/Th17 cytokine production in response to MOG35-55 in vitro. CONCLUSIONS:Peripherally-administered orexin A ameliorated EAE by reducing CNS neuroinflammation. These results suggest that orexins may represent new therapeutic candidates that should be further investigated for MS treatment.

SUBMITTER: Becquet L

PROVIDER: S-EPMC6425555 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Systemic administration of orexin A ameliorates established experimental autoimmune encephalomyelitis by diminishing neuroinflammation.

Becquet Laurine L Abad Catalina C Leclercq Mathilde M Miel Camille C Jean Laetitia L Riou Gaëtan G Couvineau Alain A Boyer Olivier O Tan Yossan-Var YV

Journal of neuroinflammation 20190320 1

<h4>Background</h4>Orexins (hypocretins, Hcrt) A and B are GPCR-binding hypothalamic neuropeptides known to regulate sleep/wake states and feeding behavior. A few studies have shown that orexin A exhibits anti-inflammatory and neuroprotective properties, suggesting that it might provide therapeutic effects in inflammatory and neurodegenerative diseases like multiple sclerosis (MS). In MS, encephalitogenic Th1 and Th17 cells trigger an inflammatory response in the CNS destroying the myelin sheath ...[more]

PMID: 30894198

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Project description:BackgroundResolution of inflammation is an active and regulated process that leads to the clearance of cell debris and immune cells from the challenged tissue, facilitating the recovery of homeostasis. This physiological response is coordinated by endogenous bioactive lipids known as specialized pro-resolving mediators (SPMs). When resolution fails, inflammation becomes uncontrolled leading chronic inflammation and tissue damage, as occurs in multiple sclerosis (MS).MethodsSPMs and the key biosynthetic enzymes involved in SPM production were analysed by metabololipidomics and qPCR in active brain lesions, serum and peripheral blood mononuclear cells (PBMC) of MS patients as well as in the spinal cord of mice with experimental autoimmune encephalomyelitis (EAE). We also tested the therapeutic actions of the SPM coined Maresin-1 (MaR1) in EAE mice and studied its impact on inflammation by doing luminex and flow cytometry analysis.ResultsWe show that levels of MaR1 and other SPMs were below the limit of detection or not increased in the spinal cord of EAE mice, whereas the production of pro-inflammatory eicosanoids was induced during disease progression. Similarly, we reveal that SPMs were undetected in serum and active brain lesion samples of MS patients, which was linked to impaired expression of the enzymes involved in the biosynthetic pathways of SPMs. We demonstrate that exogenous administration of MaR1 in EAE mice suppressed the protein levels of various pro-inflammatory cytokines and reduced immune cells counts in the spinal cord and blood. MaR1 also decreased the numbers of Th1 cells but increased the accumulation of regulatory T cells and drove macrophage polarization towards an anti-inflammatory phenotype. Importantly, we provide clear evidence that administration of MaR1 in mice with clinical signs of EAE enhanced neurological outcomes and protected from demyelination.ConclusionsThis study reveals that there is an imbalance in the production of SPMs in MS patients and in EAE mice, and that increasing the bioavailability of SPMs, such as MaR1, minimizes inflammation and mediates therapeutic actions. Thus, these data suggest that immunoresolvent therapies, such as MaR1, could be a novel avenue for the treatment of MS.

Dataset Information

Systemic administration of orexin A ameliorates established experimental autoimmune encephalomyelitis by diminishing neuroinflammation.

Publications

Systemic administration of orexin A ameliorates established experimental autoimmune encephalomyelitis by diminishing neuroinflammation.

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