Fisiopatología del modelo de Theiler: acciones terapéuticas del cannabidiol y efectos protectores en progenitores de oligodendrocitos

La gran mayoría de los estudios que se han realizado hasta el momento con el modelo de enfermedad desmielinizante inducida por el virus de Theiler (TMEV-IDD) se han centrado en el análisis de los procesos de inflamación, daño axonal y desmielinización a nivel de médula espinal, y dicho análisis sólo explica parcialmente la patología observada en pacientes con esclerosis múltiple donde se ha visto implicación de distintas áreas cerebrales. Por ello, nuestro objetivo general consistió en el estudio de la histopatología a nivel cerebral en animales infectados con el virus de Theiler a distintos tiempos post-infección, y en dos estructuras directamente relacionadas con la sintomatología motora como son el tronco cerebral y la corteza motora

2‐AG limits Theiler's virus induced acute neuroinflammation by modulating microglia and promoting MDSCs

The innate immune response is mediated by primary immune modulators such as cytokines and chemokines that together with immune cells and resident glia orchestrate CNS immunity and inflammation. Growing evidence supports that the endocannabinoid 2‐arachidonoylglycerol (2‐AG) exerts protective actions in CNS injury models. Here, we used the acute phase of Theiler's virus induced demyelination disease (TMEV‐IDD) as a model of acute neuroinflammation to investigate whether 2‐AG modifies the brain innate immune responses to TMEV and CNS leukocyte trafficking. 2‐AG or the inhibition of its hydrolysis diminished the reactivity and number of microglia at the TMEV injection site reducing their morphological complexity and modulating them towards an anti‐inflammatory state via CB2 receptors. Indeed, 2‐AG dampened the infiltration of immune cells into the CNS and inhibited their egress from the spleen, resulting in long‐term beneficial effects at the chronic phase of the disease. Intriguingly, it is not a generalized action over leukocytes since 2‐AG increased the presence and suppressive potency of myeloid derived suppressor cells (MDSCs) in the brain resulting in higher apoptotic CD4+ T cells at the injection site. Together, these data suggest a robust modulatory effect in the peripheral and central immunity by 2‐AG and highlight the interest of modulating endogenous cannabinoids to regulate CNS inflammatory conditions.This work was supported by grants to CG, DC and MLR from Ministry of the Economy and Competitiveness (CG: MINECO SAF2013–42784‐R, SAF2016 76449‐R; MLR: SAF2013–48271, DC: PI15/00963), the Comunidad de Madrid (CG: S2010/BMD‐2308 and MLR: S2010/BMD‐2353), the Red Española de Esclerosis Múltiple (CG: REEM: RD12/0032/0008; RD16/0015/0021; FC: RD12/0032/12, DC: RD16/0015/0019) sponsored by the Fondo de Investigación Sanitaria (FIS), partially financed by F.E.D.E.R.; European Union “Una manera de hacer Europa” and ARSEP Foundation to DC. Diego Clemente's group was sponsored by ADEM‐TO, Aciturri Aeronáutica S.L. and Vesuvius Ibérica LA. M.M. is a senior postdoctoral supported by the Comunidad de Madrid (S2010/BMD‐2308) and hired by MINECO; DC and IM‐D are hired by SESCAM.Peer reviewe

2-Arachidonoylglycerol Reduces Proteoglycans and Enhances Remyelination in a Progressive Model of Demyelination

The failure to undergo remyelination is a critical impediment to recovery in multiple sclerosis. Chondroitin sulfate proteoglycans (CSPGs) accumulate at demyelinating lesions creating a nonpermissive environment that impairs axon regeneration and remyelination. Here, we reveal a new role for 2-arachidonoylglycerol (2-AG), the major CNS endocannabinoid, in the modulation of CSPGs deposition in a progressive model of multiple sclerosis, the Theiler's murine encephalomyelitis virus-induced demyelinating disease. Treatment with a potent reversible inhibitor of the enzyme monoacylglycerol lipase, which accounts for 85% of the 2-AG degradation in the mouse CNS, modulates neuroinflammation and reduces CSPGs accumulation and astrogliosis around demyelinated lesions in the spinal cord of Theiler's murine encephalomyelitis virus-infected mice. Inhibition of 2-AG hydrolysis augments the number of mature oligodendrocytes and increases MBP, leading to remyelination and functional recovery of mice. Our findings establish a mechanism for 2-AG promotion of remyelination with implications in axonal repair in CNS demyelinating pathologies.This work was supported by Ministry of the Economy and Competition (MINECO) Grants SAF2013-42784-R and SAF2016-76449-R, Comunidad de Madrid Grant S2011/BMD-2308, and Red Española de Esclerosis Múltiple Grants RD12/0032/0008 and RD16/0015/0021 (sponsored by the Fondo de Investigación Sanitaria) to C.G., Basque Government Grant IT764-13, MINECO/FEDER Grant SAF2015-65034-R, and University of the Basque Country Grant UPV/EHU UFI11/41 to P.G., and MINECO Grant SAF2013-48271-C2-1-R to M.L.-R. None of the funding bodies played any role in the study design, data collection and analysis, the decision to publish, or the preparation of the manuscript. A.F. is a predoctoral fellow supported by MINECO Grant BES-2014-068459. We thank Laura Ramos for excellent technical support.Peer reviewe

Development of a Fluorescent Bodipy Probe for Visualization of the Serotonin 5-HT1A Receptor in Native Cells of the Immune System

Serotonin (5-HT) modulates key aspects of the immune system. However, its precise function and the receptors involved in the observed effects have remained elusive. Among the different serotonin receptors, 5-HT1A plays an important role in the immune system given its presence in cells involved in both the innate and adaptive immune responses, but its actual levels of expression under different conditions have not been comprehensively studied due to the lack of suitable tools. To further clarify the role of 5-HT1A receptor in the immune system, we have developed a fluorescent small molecule probe that enables the direct study of the receptor levels in native cells. This probe allows direct profiling of the receptor expression in immune cells using flow cytometry. Our results show that important subsets of immune cells including human monocytes and dendritic cells express functional 5-HT1A and that its activation is associated with anti-inflammatory signaling. Furthermore, application of the probe to the experimental autoimmune encephalomyelitis model of multiple sclerosis demonstrates its potential to detect the specific overexpression of the 5-HT1A receptor in CD4+ T cells. Accordingly, the probe reported herein represents a useful tool whose use can be extended to study the levels of 5-HT1A receptor in ex vivo samples of different immune system conditions