Current Understanding of the Glial Response to Disorders of the Aging CNS

In this special issue of Frontiers in Pharmacology, we have asked leading experts to comment and review the evidence that inflammatory cells play a leading role in the pathological processes underlying neurodegenerative disorders. We now seek to draw these various observations together into a conclusion, with the hope that this will inform further work in this area and result in the identification of new therapeutic targets that will have a disease modifying effect

Assessing social and economic impact of subcutaneous mAbs in oncology

Background: Rituximab and trastuzumab were the first monoclonal antibodies (mAbs) approved for the treatment of cancer patients. Both antibodies are administered intravenously (EV), but subcutaneous (SC) formulations have recently been developed. SC formulations proved to be as safe and effective as EV and to offer substantial benefits to the patient. Objective: The aim of this study was to provide a multidimensional assessment of the impact of rituximab and trastuzumab SC compared to the EV formulation, providing a particular focus on expected social and economic benefits for the patient. Methods: The best established HTA methods were applied to gather and organize evidence concerning the clinical, economic, organizational, social and ethical impact of SC formulations of rituximab and trastuzumab. Social aspects were investigated applying regression methods to data collected with a previous research, while the potential savings associated with the use of SC formulations were estimated by a simple economic model applying the societal perspective. Results Patients undergoing subcutaneous formulation are significantly more satisfied with their treatment experience than those treated with intravenous formulation. Subcutaneous formulation reduces patient dosing times, with a positive effect on the care provider's autonomy and productivity. Potential savings associated with the use of rituximab SC were estimated in € 4,050 per patient per year on average. For trastuzumab SC the estimated potential savings amounted to € 3,400 per patient per year, on average. Conclusion Rituximab and trastuzumab are promising treatment options significantly improving patients qol and reducing the treatment burden in terms of societal costs

Defining Midbrain Dopaminergic Neuron Diversity by Single-Cell Gene Expression Profiling

SummaryEffective approaches to neuropsychiatric disorders require detailed understanding of the cellular composition and circuitry of the complex mammalian brain. Here, we present a paradigm for deconstructing the diversity of neurons defined by a specific neurotransmitter using a microfluidic dynamic array to simultaneously evaluate the expression of 96 genes in single neurons. With this approach, we successfully identified multiple molecularly distinct dopamine neuron subtypes and localized them in the adult mouse brain. To validate the anatomical and functional correlates of molecular diversity, we provide evidence that one Vip+ subtype, located in the periaqueductal region, has a discrete projection field within the extended amygdala. Another Aldh1a1+ subtype, located in the substantia nigra, is especially vulnerable in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson’s disease. Overall, this rapid, cost-effective approach enables the identification and classification of multiple dopamine neuron subtypes, with distinct molecular, anatomical, and functional properties

Platelet-derived extracellular vesicles in Huntington's disease.

The production and release of extracellular vesicles (EV) is a property shared by all eukaryotic cells and a phenomenon frequently exacerbated in pathological conditions. The protein cargo of EV, their cell type signature and availability in bodily fluids make them particularly appealing as biomarkers. We recently demonstrated that platelets, among all types of blood cells, contain the highest concentrations of the mutant huntingtin protein (mHtt)-the genetic product of Huntington's disease (HD), a neurodegenerative disorder which manifests in adulthood with a complex combination of motor, cognitive and psychiatric deficits. Herein, we used a cohort of 59 HD patients at all stages of the disease, including individuals in pre-manifest stages, and 54 healthy age- and sex-matched controls, to evaluate the potential of EV derived from platelets as a biomarker. We found that platelets of pre-manifest and manifest HD patients do not release more EV even if they are activated. Importantly, mHtt was not found within EV derived from platelets, despite them containing high levels of this protein. Correlation analyses also failed to reveal an association between the number of platelet-derived EV and the age of the patients, the number of CAG repeats, the Unified Huntington Disease Rating Scale total motor score, the Total Functional Capacity score or the Burden of Disease score. Our data would, therefore, suggest that EV derived from platelets with HD is not a valuable biomarker in HD.The study was funded by an operating grant from the Merck Sharpe & Dohme to F.C. who is also a recipient of a National Researcher career award from the Fonds de Recherche du Québec en santé (FRQS) providing salary support and operating funds. I.S.-A. was supported by a CIHR-Huntington Society of Canada postdoctoral fellowship. R.A.B. and S.L.M. are supported by a National Institute for Health Research (NIHR) award of a Biomedical Research Center to the University of Cambridge and Addenbrooke’s Hospital. E.B. is supported by the Canadian Institutes of Health Research. N.D. MD-MSc. also funded by CIHR and by Canadian Consortium on Neurodegeneration in Aging (CCNA). HLD and JPL hold a Desjardins scholarship from the Fondation du CHU de Québec. HLD hold a bourse d’excellence du Centre Thématique de Recherche en Neurosciences (CTRN) du CHU de Québec. The authors would like to thank all the students and staff who helped with the blood collections in Cambridge, Quebec City and Montreal and importantly, all patients and their families for being so generous with their time in participating to this stud

MS-275 (Entinostat) Promotes Radio-sensitivity in PAX3-FOXO1 Rhabdomyosarcoma cells

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood. About 25% of RMS expresses fusion oncoproteins such as PAX3/PAX7‐FOXO1 (fusion‐positive, FP) while fusion‐negative (FN)‐RMS harbors RAS mutations. Radiotherapy (RT) plays a crucial role in local control but metastatic RMS is often radio‐resistant. HDAC inhibitors (HDACi) radio‐sensitize different cancer cells types. Thus, we evaluated MS−275 (Entinostat), a Class I and IV HDACi, in combination with RT on RMS cells in vitro and in vivo. MS−275 reversibly hampered cell survival in vitro in FN‐RMS RD (RASmut) and irreversibly in FP‐RMS RH30 cell lines down‐regulating cyclin A, B, and D1, up‐regulating p21 and p27 and reducing ERKs activity, and c‐Myc expression in RD and PI3K/Akt/mTOR activity and N‐Myc expression in RH30 cells. Further, MS−275 and RT combination reduced colony formation ability of RH30 cells. In both cell lines, co‐treatment increased DNA damage repair inhibition and reactive oxygen species formation, down‐regulated NRF2, SOD, CAT and GPx4 anti‐oxidant genes and improved RT ability to induce G2 growth arrest. MS−275 inhibited in vivo growth of RH30 cells and completely prevented the growth of RT‐unresponsive RH30 xenografts when combined with radiation. Thus, MS−275 could be considered as a radio‐sensitizing agent for the treatment of intrinsically radio‐resistant PAX3‐FOXO1 RMS

The role of tau in the pathological process and clinical expression of Huntington's disease.

Huntington's disease is a neurodegenerative disorder caused by an abnormal CAG repeat expansion within exon 1 of the huntingtin gene HTT. While several genetic modifiers, distinct from the Huntington's disease locus itself, have been identified as being linked to the clinical expression and progression of Huntington's disease, the exact molecular mechanisms driving its pathogenic cascade and clinical features, especially the dementia, are not fully understood. Recently the microtubule associated protein tau, MAPT, which is associated with several neurodegenerative disorders, has been implicated in Huntington's disease. We explored this association in more detail at the neuropathological, genetic and clinical level. We first investigated tau pathology by looking for the presence of hyperphosphorylated tau aggregates, co-localization of tau with mutant HTT and its oligomeric intermediates in post-mortem brain samples from patients with Huntington's disease (n = 16) compared to cases with a known tauopathy and healthy controls. Next, we undertook a genotype-phenotype analysis of a large cohort of patients with Huntington's disease (n = 960) with a particular focus on cognitive decline. We report not only on the tau pathology in the Huntington's disease brain but also the association between genetic variation in tau gene and the clinical expression and progression of the disease. We found extensive pathological inclusions containing abnormally phosphorylated tau protein that co-localized in some instances with mutant HTT. We confirmed this related to the disease process rather than age, by showing it is also present in two patients with young-onset Huntington's disease (26 and 40 years old at death). In addition we demonstrate that tau oligomers (suggested to be the most likely neurotoxic tau entity) are present in the Huntington's disease brains. Finally we highlight the clinical significance of this pathology by demonstrating that the MAPT haplotypes affect the rate of cognitive decline in a large cohort of patients with Huntington's disease. Our findings therefore highlight a novel important role of tau in the pathogenic process and clinical expression of Huntington's disease, which in turn opens up new therapeutic avenues for this incurable condition.The authors thank the EHDN REGISTRY Study Group investigators (listed in the Supplementary material) for collecting the data and all participating REGISTRY patients for their time and efforts, the Cambridge Brain Bank for the post-mortem tissue which is supported by a grant to the NIHR Cambridge Biomedical Research Centre and in particular to J. Wilson and Dr D. O’ Donovan. We are grateful to S. Sawcer and M. Ban in the Neurology Unit at the University of Cambridge, for their help with the genotyping, C.H. Williams-Gray at the John van Geest Centre for Brain Repair, University of Cambridge, for her help with the statistical analyses, J. Hardy, J.L. Holton, and T. Revesz at the UCL Institute of Neurology for their helpful discussions as well as K. Strand, F. Javad and A. Posada Bórbon, at the UCL Institute of Neurology, for their support with the experimental work, R. Kayed at the University of Texas Medical Branch, Galveston, for providing the TOMA and T22 antibodies. Finally, P. Tyers, R. Raha-Chowdhury, A. Tolkovsky, B. Ossola and J. Simpson for their support and encouragement throughout this work.This is the final version of the article. It was first available from Oxford University Press viahttp://dx.doi.org/10.1093/brain/awv10

Cerebrovascular and blood-brain barrier impairments in Huntington's disease: Potential implications for its pathophysiology: Vascular impairments in HD

ObjectiveAlthough the underlying cause of Huntington's disease (HD) is well established, the actual pathophysiological processes involved remain to be fully elucidated. In other proteinopathies such as Alzheimer's and Parkinson's diseases, there is evidence for impairments of the cerebral vasculature as well as the blood–brain barrier (BBB), which have been suggested to contribute to their pathophysiology. We investigated whether similar changes are also present in HD.MethodsWe used 3‐ and 7‐Tesla magnetic resonance imaging as well as postmortem tissue analyses to assess blood vessel impairments in HD patients. Our findings were further investigated in the R6/2 mouse model using in situ cerebral perfusion, histological analysis, Western blotting, as well as transmission and scanning electron microscopy.ResultsWe found mutant huntingtin protein (mHtt) aggregates to be present in all major components of the neurovascular unit of both R6/2 mice and HD patients. This was accompanied by an increase in blood vessel density, a reduction in blood vessel diameter, as well as BBB leakage in the striatum of R6/2 mice, which correlated with a reduced expression of tight junction‐associated proteins and increased numbers of transcytotic vesicles, which occasionally contained mHtt aggregates. We confirmed the existence of similar vascular and BBB changes in HD patients.InterpretationTaken together, our results provide evidence for alterations in the cerebral vasculature in HD leading to BBB leakage, both in the R6/2 mouse model and in HD patients, a phenomenon that may, in turn, have important pathophysiological implications. Ann Neurol 2015;78:160–17

Portrait of blood-derived extracellular vesicles in patients with Parkinson's disease.

The production of extracellular vesicles (EV) is a ubiquitous feature of eukaryotic cells but pathological events can affect their formation and constituents. We sought to characterize the nature, profile and protein signature of EV in the plasma of Parkinson's disease (PD) patients and how they correlate to clinical measures of the disease. EV were initially collected from cohorts of PD (n = 60; Controls, n = 37) and Huntington's disease (HD) patients (Pre-manifest, n = 11; manifest, n = 52; Controls, n = 55) - for comparative purposes in individuals with another chronic neurodegenerative condition - and exhaustively analyzed using flow cytometry, electron microscopy and proteomics. We then collected 42 samples from an additional independent cohort of PD patients to confirm our initial results. Through a series of iterative steps, we optimized an approach for defining the EV signature in PD. We found that the number of EV derived specifically from erythrocytes segregated with UPDRS scores corresponding to different disease stages. Proteomic analysis further revealed that there is a specific signature of proteins that could reliably differentiate control subjects from mild and moderate PD patients. Taken together, we have developed/identified an EV blood-based assay that has the potential to be used as a biomarker for PD