Ramifications of microglial activation on oligodendrocytes in in vitro models of multiple sclerosis

Oligodendrocytes are the principal target of immune attack in multiple sclerosis (MS), where the immune system attacks the myelin sheath, leading to oligodendrocyte demise, compromised axonal saltatory conduction and eventually neuronal degeneration. Microglia are also implicated in MS pathology and are present in lesions in an activated state. To study the effects of activated microglia on oligodendrocyte precursor cells (OPCs) or mature oligodendrocytes, primary cultures of microglia, oligodendrocytes, or co-cultures of the two cell populations were developed. Microglia activated with lipopolysaccharide (LPS), were toxic to OPCs and mature oligodendrocytes in co-culture. This toxicity was mediated by tumour necrosis factor α (TNF-α) released from microglia. Microglial activation with the blood-borne proteins (BBPs) fraction V albumin, fibrinogen and fibrin was also investigated. BBPs enter the brain after blood-brain barrier disruption, a typical event in MS, so their differential effect upon microglial activation and subsequently oligodendrocyte lineage cell maturation survival was studied. BBPs had distinct effects on microglial activation and oligodendrocyte cell toxicity. Fraction V albumin and fibrin were directly toxic to oligodendrocytes while microglial activation protected oligodendrocytes in co-culture. Fibrin also inhibited OPC maturation into myelinating oligodendrocytes. Fibrinogen activated microglia were toxic to OPCs and mature oligodendrocytes in co-culture. Attenuation of microglial induced oligodendrocyte death was attempted by blocking pathways of microglial activation such as the Rho-ROCK pathway and by modulating microglial activation by metabotropic glutamate receptor manipulation. Additionally, ROCK inhibition was able to attenuate LPS or BBP activated microglial expression of inducible nitric oxide synthase (iNOS). Modulation of microglial activation could prevent microglial induced oligodendrocyte toxicity and could lead to strategies to slow disease progression in MS patients by protecting mature oligodendrocytes from microglial induced death, or most importantly by enhancing survival and maturation of OPCs in MS lesions, where their recruitment to remyelinate neuronal axons is vital for disease remission

Assessing the suitability of a range of benthic indices in the evaluation of environmental impact of fin and shellfish aquaculture located in sites across Europe

The European Union-funded ECASA project (Ecosystem Approach for Sustainable Aquaculture) studied the impacts from aquaculture on ecosystems from northern Norway to Greece. The objectives of this investigation were to identify quantitative indicators of the effects of aquaculture on marine communities, and to assess their applicability over a range of ecosystems and aquaculture production systems. The study included 6 Mediterranean and 4 Atlantic sites, 7 ofwhich produced finfish (seabream, seabass, tuna, salmon and cod), and 2 bivalve molluscs (oysters, mussels, and clams); one site produced both fish and bivalves. Cultivation methods included finfish cages, long-lines and trestles. Similar sampling methodologies were employed at the 10 study sites, obtaining sediment, hydrodynamic, and benthic faunal data. The horizontal impact from organic enrichment extended 50m from the farms, with contradictory responses in several indicators (individual abundance, biomass) and a more consistent response of the Infaunal Trophic Index (ITI) and AZTI'sMarine Biotic Index (AMBI). By means of Partial Redundancy Analysis, it was demonstrated that the environmental variables explained 53.2% of the variability in the macrofaunal variables (individual abundance, species richness, diversity, AMBI and ITI), whilst the explained variance was partialled out within three groups of variables: (i) ‘hydrography’ (depth, distance to farm, average current speed), which explained 11.5% of the variance; (ii) ‘sediment’ (Eh and percentages of silt and total organic matter), which explained 5.4%; and (iii) ‘cages’ (years of production and annual production), which explained 15.2%. The shared variance explained by interactions among these groups was 21.1%. These results, together with multiple regression analysis, provide an accurate assessment of the degree of impact from aquaculture. In conclusion, the use of several benthic indicators, in assessing farm impacts, together with the investigation of dynamics of the studied location, water depth, years of farm activity, and total annual production, must be included when interpreting the response of benthic communities to organic enrichment from aquaculture

Big conductance calcium-activated potassium channel openers control spasticity without sedation.

BACKGROUND AND PURPOSE: Our initial aim was to generate cannabinoid agents that control spasticity, occurring as a consequence of multiple sclerosis (MS), whilst avoiding the sedative side effects associated with cannabis. VSN16R was synthesized as an anandamide (endocannabinoid) analogue in an anti-metabolite approach to identify drugs that target spasticity. EXPERIMENTAL APPROACH: Following the initial chemistry, a variety of biochemical, pharmacological and electrophysiological approaches, using isolated cells, tissue-based assays and in vivo animal models, were used to demonstrate the activity, efficacy, pharmacokinetics and mechanism of action of VSN16R. Toxicological and safety studies were performed in animals and humans. KEY RESULTS: VSN16R had nanomolar activity in tissue-based, functional assays and dose-dependently inhibited spasticity in a mouse experimental encephalomyelitis model of MS. This effect occurred with over 1000-fold therapeutic window, without affecting normal muscle tone. Efficacy was achieved at plasma levels that are feasible and safe in humans. VSN16R did not bind to known CB1 /CB2 /GPPR55 cannabinoid-related receptors in receptor-based assays but acted on a vascular cannabinoid target. This was identified as the major neuronal form of the big conductance, calcium-activated potassium (BKCa ) channel. Drug-induced opening of neuronal BKCa channels induced membrane hyperpolarization, limiting excessive neural-excitability and controlling spasticity. CONCLUSIONS AND IMPLICATIONS: We identified the neuronal form of the BKCa channel as the target for VSN16R and demonstrated that its activation alleviates neuronal excitability and spasticity in an experimental model of MS, revealing a novel mechanism to control spasticity. VSN16R is a potential, safe and selective ligand for controlling neural hyper-excitability in spasticity

Pre-clinical characterisation of E2814, a high-affinity antibody targeting the microtubule-binding repeat domain of tau for passive immunotherapy in Alzheimer's disease

Tau deposition in the brain is a pathological hallmark of many neurodegenerative disorders, including Alzheimer’s disease (AD). During the course of these tauopathies, tau spreads throughout the brain via synaptically-connected pathways. Such propagation of pathology is thought to be mediated by tau species (“seeds”) containing the microtubule binding region (MTBR) composed of either three repeat (3R) or four repeat (4R) isoforms. The tau MTBR also forms the core of the neuropathological filaments identified in AD brain and other tauopathies. Multiple approaches are being taken to limit tau pathology, including immunotherapy with anti-tau antibodies. Given its key structural role within fibrils, specifically targetting the MTBR with a therapeutic antibody to inhibit tau seeding and aggregation may be a promising strategy to provide disease-modifying treatment for AD and other tauopathies. Therefore, a monoclonal antibody generating campaign was initiated with focus on the MTBR. Herein we describe the pre-clinical generation and characterisation of E2814, a humanised, high affinity, IgG1 antibody recognising the tau MTBR. E2814 and its murine precursor, 7G6, as revealed by epitope mapping, are antibodies bi-epitopic for 4R and mono-epitopic for 3R tau isoforms because they bind to sequence motif HVPGG. Functionally, both antibodies inhibited tau aggregation in vitro. They also immunodepleted a variety of MTBR-containing tau protein species. In an in vivo model of tau seeding and transmission, attenuation of deposition of sarkosyl-insoluble tau in brain could also be observed in response to antibody treatment. In AD brain, E2814 bound different types of tau filaments as shown by immunogold labelling and recognised pathological tau structures by immunohistochemical staining. Tau fragments containing HVPGG epitopes were also found to be elevated in AD brain compared to PSP or control. Taken together, the data reported here have led to E2814 being proposed for clinical developmen

Where Is More Important Than How in Coastal and Marine Ecosystems Restoration

Restoration is considered an effective strategy to accelerate the recovery of biological communities at local scale. However, the effects of restoration actions in the marine ecosystems are still unpredictable. We performed a global analysis of published literature to identify the factors increasing the probability of restoration success in coastal and marine systems. Our results confirm that the majority of active restoration initiatives are still concentrated in the northern hemisphere and that most of information gathered from restoration efforts derives from a relatively small subset of species. The analysis also indicates that many studies are still experimental in nature, covering small spatial and temporal scales. Despite the limits of assessing restoration effectiveness in absence of a standardized definition of success, the context (degree of human impact, ecosystem type, habitat) of where the restoration activity is undertaken is of greater relevance to a successful outcome than how (method) the restoration is carried out. Contrary to expectations, we found that restoration is not necessarily more successful closer to protected areas (PA) and in areas of moderate human impact. This result can be motivated by the limits in assessing the success of interventions and by the tendency of selecting areas in more obvious need of restoration, where the potential of actively restoring a degraded site is more evident. Restoration sites prioritization considering human uses and conservation status present in the region is of vital importance to obtain the intended outcomes and galvanize further actions

Where Is More Important Than How in Coastal and Marine Ecosystems Restoration

Restoration is considered an effective strategy to accelerate the recovery of biological communities at local scale. However, the effects of restoration actions in the marine ecosystems are still unpredictable.We performed a global analysis of published literature to identify the factors increasing the probability of restoration success in coastal and marine systems. Our results confirm that the majority of active restoration initiatives are still concentrated in the northern hemisphere and that most of information gathered from restoration efforts derives from a relatively small subset of species. The analysis also indicates that many studies are still experimental in nature, covering small spatial and temporal scales. Despite the limits of assessing restoration effectiveness in absence of a standardized definition of success, the context (degree of human impact, ecosystem type, habitat) of where the restoration activity is undertaken is of greater relevance to a successful outcome than how (method) the restoration is carried out. Contrary to expectations, we found that restoration is not necessarily more successful closer to protected areas (PA) and in areas of moderate human impact. This result can be motivated by the limits in assessing the success of interventions and by the tendency of selecting areas in more obvious need of restoration, where the potential of actively restoring a degraded site is more evident. Restoration sites prioritization considering human uses and conservation status present in the region is of vital importance to obtain the intended outcomes and galvanize further actions

Ramifications of microglial activation on oligodendrocytes in in vitro models of multiple sclerosis.

Oligodendrocytes are the principal target of immune attack in multiple sclerosis (MS), where the immune system attacks the myelin sheath, leading to oligodendrocyte demise, compromised axonal saltatory conduction and eventually neuronal degeneration. Microglia are also implicated in MS pathology and are present in lesions in an activated state. To study the effects of activated microglia on oligodendrocyte precursor cells (OPCs) or mature oligodendrocytes, primary cultures of microglia, oligodendrocytes, or co-cultures of the two cell populations were developed. Microglia activated with lipopolysaccharide (LPS), were toxic to OPCs and mature oligodendrocytes in co-culture. This toxicity was mediated by tumour necrosis factor α (TNF-α) released from microglia. Microglial activation with the blood-borne proteins (BBPs) fraction V albumin, fibrinogen and fibrin was also investigated. BBPs enter the brain after blood-brain barrier disruption, a typical event in MS, so their differential effect upon microglial activation and subsequently oligodendrocyte lineage cell maturation survival was studied. BBPs had distinct effects on microglial activation and oligodendrocyte cell toxicity. Fraction V albumin and fibrin were directly toxic to oligodendrocytes while microglial activation protected oligodendrocytes in co-culture. Fibrin also inhibited OPC maturation into myelinating oligodendrocytes. Fibrinogen activated microglia were toxic to OPCs and mature oligodendrocytes in co-culture. Attenuation of microglial induced oligodendrocyte death was attempted by blocking pathways of microglial activation such as the Rho-ROCK pathway and by modulating microglial activation by metabotropic glutamate receptor manipulation. Additionally, ROCK inhibition was able to attenuate LPS or BBP activated microglial expression of inducible nitric oxide synthase (iNOS). Modulation of microglial activation could prevent microglial induced oligodendrocyte toxicity and could lead to strategies to slow disease progression in MS patients by protecting mature oligodendrocytes from microglial induced death, or most importantly by enhancing survival and maturation of OPCs in MS lesions, where their recruitment to remyelinate neuronal axons is vital for disease remission.