A study of microglial metabotropic glutamate receptor modulation of inflammation.

Microglia are the immune cell of the central nervous system and become reactive in response to infection or trauma. In Multiple Sclerosis (MS) microglia show early reactivity which may contribute to subsequent neurotoxicity. Glutamate has been implicated in the neurodegeneration in MS. Microglia express subtypes of metabotropic glutamate receptors (mGluRs), the activation of which can lead to microglial evoked neurotoxicity (group II) or neuroprotection (group III). This suggests that release of glutamate from neurones or glial cells may activate microglia via these receptors. Increased microglial reactivity during disease is possibly due to an imbalance of mGluR expression with neurotoxic group II increased above neuroprotective group III mGluRs. Microglial expression of mGluR subtypes was therefore investigated on activated compared with untreated cells. It was found that microglia exposed to myelin expressed increased levels of group II and mGluRl and 8 subtypes compared with control cells. MS is characterised by lesions in the CNS due to localised myelin breakdown. This research investigated the effects of microglial exposure to myelin and demonstrated that myelin induced microglial activation, upregulation of iNOS expression, and increased TNFa and nitrite release. Conditioned medium from these cells was toxic to neurones in culture. Microglia phagocytose myelin in vitro leading to cytokine release and increased affinity for oligodendrocytes, inducing their death by cell contact through TNF receptors. This study examined whether microglial phagocytosis could be modulated by stimulation of mGluRs and demonstrated that blocking group II or stimulation of group I or III mGluRs significantly reduced phagocytic activity. Since myelin induced toxicity was also reduced by blocking microglial group II or stimulating group III mGluRs, these results suggest that modulation of microglial mGluRs may be of therapeutic benefit in MS

Oxygen-glucose deprivation and interleukin-1α trigger the release of perlecan LG3 by cells of neurovascular unit

[Image: see text] Two of the main stresses faced by cells at the NVU as an immediate result of cerebral ischemia are oxygen-glucose deprivation (OGD)/reperfusion and inflammatory stress caused by up regulation of IL-1. As a result of these stresses, perlecan, an important component of the NVU extracellular matrix (ECM), is highly proteolyzed. Here we describe that focal cerebral ischemia in rats results in increased generation of LG3, the c-terminal bioactive fragment of perlecan. Further, in vitro study of the cells of the NVU was performed to locate the source of this increased perlecan-LG3. Neurons, astrocytes, brain endothelial cells and pericytes were exposed to OGD/reperfusion and IL-1α/β. It was observed that neurons and pericytes showed increased levels of LG3 during OGD in their culture media. During in vitro reperfusion, neurons, astrocytes and pericytes showed elevated levels of LG3, but only after exposure to brief durations of OGD. IL-1α and IL-1β treatment tended to have opposite effects on NVU cells. While IL-1α increased or had minimal to no effect on LG3 generation, high concentrations of IL-1β decreased it in most cells studied. Finally, LG3 was determined to be neuroprotective and anti-proliferative in brain endothelial cells, suggesting a possible role for the generation of LG3 in the ischemic brain

Adhesion to the extracellular matrix is required for interleukin-1 beta actions leading to reactive phenotype in rat astrocytes

The extracellular matrix (ECM) of the brain is essential for homeostasis and normal functions, but is rapidly remodelled during acute brain injury alongside the development of an inflammatory response driven by the cytokine interleukin (IL)-1. Whether the ECM regulates IL-1 actions in astrocytes is completely unknown. The aim of this study was to test the hypothesis that cellular attachment to the ECM is a critical mediator of IL-1β-induced signalling pathways and development of reactive phenotype in astrocytes. Primary rat astrocytes adhered to fibronectin, laminin and fibrillin-1 in an integrin-dependent manner. Attachment to these ECM molecules significantly increased IL-1β-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and inhibition of RhoA and Rho kinase (ROCK), coincident with loss of focal adhesions and cellular morphological changes. Our data demonstrate that the ECM regulates IL-1 actions in astrocytes via cross-talk mechanisms between ERK1/2 and RhoA/ROCK, which could have important implications in brain inflammatory disorders

Therapeutic potential of extracellular vesicles in preclinical stroke models : a systematic review and meta-analysis

Funding: This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) Doctoral Prize Fellowship grant EP/N509565/1 and EPSRC and Medical Research Council (MRC) Centre for Doctoral Training in Regenerative Medicine studentship grant EP/L014904/1.Peer reviewedPublisher PD

Changes in the secretome of tri-dimensional spheroid-cultured human mesenchymal stem cells in vitro by interleukin-1 priming

Funding The work was supported with funds from the Stroke Association and from EPSRC, MRC Centre for Doctoral Training in Regenerative Medicine studentship grant EP/L014904/1, and the Manchester Regenerative Medicine Network (MaRM). Availability of data and materials The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.Peer reviewedPublisher PD

Regenerative Medicine Therapies for Targeting Neuroinflammation After Stroke

Inflammation is a major pathological event following ischemic stroke that contributes to secondary brain tissue damage leading to poor functional recovery. Following the initial ischemic insult, post-stroke inflammatory damage is driven by initiation of a central and peripheral innate immune response and disruption of the blood-brain barrier (BBB), both of which are triggered by the release of pro-inflammatory cytokines and infiltration of circulating immune cells. Stroke therapies are limited to early cerebral blood flow reperfusion, and whilst current strategies aim at targeting neurodegeneration and/or neuroinflammation, innovative research in the field of regenerative medicine aims at developing effective treatments that target both the acute and chronic phase of inflammation. Anti-inflammatory regenerative strategies include the use of nanoparticles and hydrogels, proposed as therapeutic agents and as a delivery vehicle for encapsulated therapeutic biological factors, anti-inflammatory drugs, stem cells, and gene therapies. Biomaterial strategies—through nanoparticles and hydrogels—enable the administration of treatments that can more effectively cross the BBB when injected systemically, can be injected directly into the brain, and can be 3D-bioprinted to create bespoke implants within the site of ischemic injury. In this review, these emerging regenerative and anti-inflammatory approaches will be discussed in relation to ischemic stroke, with a perspective on the future of stroke therapies

Systemic conditioned medium treatment from interleukin-1 primed mesenchymal stem cells promotes recovery after stroke

This work was supported by the Engineering and Physical Sciences Research Council (EPSRC, UK) and Medical Research Council (MRC, UK) Centre for Doctoral Training in Regenerative Medicine studentship grant EP/L014904/1 and the Stroke Association (TSA 2017/03).Peer reviewedPublisher PD

Cell-specific conditional deletion of interleukin-1 (IL-1) ligands and its receptors : a new toolbox to study the role of IL-1 in health and disease

The pro-inflammatory cytokine interleukin-1 (IL-1) plays a key role in many physiological processes and during the inflammatory and immune response to most common diseases. IL-1 exists as two agonists, IL-1α and IL-1β that bind to the only signaling IL-1 type 1 receptor (IL-1R1), while a second decoy IL-1 type 2 receptor (IL-1R2) binds both forms of IL-1 without inducing cell signaling. The field of immunology and inflammation research has, over the past 35 years, unraveled many mechanisms of IL-1 actions, through in vitro manipulation of the IL-1 system or by using genetically engineered mouse models that lack either member of the IL-1 family in ubiquitous constitutive manner. However, the limitation of global mouse knockout technology has significantly hampered our understanding of the precise mechanisms of IL-1 actions in animal models of disease. Here we report and review the recent generation of new conditional mouse mutants in which exons of Il1a, Il1b, Il1r1, and Il1r2 genes flanked by loxP sites (fl/fl) can be deleted in cell-/tissue-specific constitutive or inducible manner by Cre recombinase expression. Hence, IL-1αfl/fl, IL-1βfl/fl, IL-1R1fl/fl, and IL-1R2fl/fl mice constitute a new toolbox that will provide a step change in our understanding of the cell-specific role of IL-1 and its receptor in health and disease and the potential development of targeted IL-1 therapies

The role of interleukin-1 receptors in brain cell signalling

IL-1α and IL-1β are two IL-1 agonists which signals at the same receptor complex composed of IL-1R1/IL-1RAcP. However, IL-1α and IL-1β exert differential actions. A recent CNS-specific IL-1 receptor accessory protein, called IL-1RAcPb, has been characterised but its actions are unknown. In T cell line, over expression of IL-1RAcPb negatively regulate IL-1 action (Smith et al, 2009), but over-expression of IL-1RAcPb in HEK cell line induces IL-1 signaling (Lu et al, 2008). The role of IL-1RAcPb has not been studied in primary cells. The aim of this project was to investigate the role of IL-1RAcPb in IL-1-induced actions in neurones and glia, and to determine IL-1α and IL-1β differential actions in these two cell types. The role of IL-1RAcPb in IL-1-induced protein expression and IL 1α and IL-1β differential effects were investigated by treating WT and IL 1RAcPb-/- neurones and glia with IL-1α or IL-1β in the presence or absence of IL-1RA for 24 h followed by assessment of IL-6 induction by ELISA. The mechanism of IL-1RAcPb actions were studied by examining the effects of IL-1α or IL-1β on p38, ERK1/2 and Src kinase activation in neurones and glia by Western blot analysis. SB203580 (p38 inhibitor), UO126 (ERK1/2 inhibitor), and PP2 (Src kinase inhibitor) were used to determine the contribution of p38, ERK1/2 and Src kinase activation to IL-1-induced IL-6 synthesis in neuronal cultures. In WT neurones, IL-1α and IL-1β were equipotent at inducing IL-6 synthesis and p38 activation, whilst both ligands failed to induce ERK1/2 or Src kinase activation. In IL-1RAcPb-/- neurones, IL-1α and IL-1β induced similar levels of IL-6, but IL-1β was more potent than IL-1α at inducing p38 activation. IL-1α-induced p38 activation was reduced in IL-1RAcPb-/- neurones compared to WT neurones. In contrast to WT neurones, ERK1/2 was activated in IL-1RAcPb-/- neurones in response to IL-1α, whilst Src kinase was not activated by IL-1α or IL 1β. IL-1-induced IL-6 synthesis was abolished by IL-1RA, SB203580, UO126 and PP2. Interestingly PP2, a specific Src kinase inhibitor also partially inhibited basal ERK1/2 activity. In WT glial cells, IL-1α was more potent than IL-1β at inducing IL-6 synthesis but both cytokines induced ERK1/2 activation with equal potency. In IL-1RAcPb-/- glia, IL-1α and IL-1β were equally potent at inducing IL-6 synthesis and ERK1/2 activation. However, IL-α-induced-IL-6 synthesis was reduced in IL 1RAcPb-/- glia compared to WT glia. In both WT and IL-1RAcPb-/- glia, IL-1α and IL-1β induced p38 activation but not Src kinase activation . In conclusion, this study showed that in neurones, IL-1RAcPb may contribute to IL-1α-induced p38 activation but negatively regulates IL-1-induced ERK1/2 activation, therefore IL-1RAcPb may have specific effects on different signalling pathways. The effect of IL-1RAcPb could also be cell specific, as IL 1RAcPb contributed to IL-1α-induced p38 signalling in neurones but IL-6 production in glia. The role of IL-1RAcPb remains largely unknown and more investigations are required to elucidate its role in IL-1 signalling in the brain.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Evaluation of the CHUMS Child Bereavement Group : A Pilot Study Examining Statistical and Clinical Change

This is an Accepted Manuscript of an article published by Taylor & Francis in Death Studies on 7 February 2015, available online at: http://dx.doi.org/10.1080/07481187.2014.913085.This article describes the largest evaluation of a UK child bereavement service to date. Change was assessed using conventional statistical tests as well as clinical significance methodology. Consistent with the fact that the intervention was offered on a universal, preventative basis, bereaved young people experienced a statistically significant, small to medium-sized decrease in symptoms over time. This change was equivalent across child age and gender. Type of bereavement had a slight impact on change when rated by parents. Potential clinical implications are highlighted, and various limitations are discussed that we hope to address using an experimental design in future researchPeer reviewedFinal Accepted Versio