The release of mitochondrial cytochrome c by genotoxic stress induces the formation of a cytosolic complex with Apaf-1 (mammalian CED4 homolog) and thereby the activation of procaspase-3 (cas-3) and procaspase-9 (cas-9). Here we demonstrate that heat-shock protein 27 (Hsp27) inhibits cytochrome c (cyt c)-dependent activation of cas-3. Hsp27 had no e ect on cyt c release, Apaf-1 and cas-9 activation. By contrast, our results show that Hsp27 associates with cas-3, but not Apaf-1 or cas-9, and inhibits activation of cas-3 by cas-9-mediated proteolysis. Furthermore, the present results demonstrate that immunodepletion of Hsp27 depletes cas-3. Importantly, treatment of cells with DNA damaging agents dissociates the Hsp27/cas-3 complex and relieves inhibition of cas-3 activation. These ®ndings de®ne a novel function for Hsp27 and provide the ®rst evidence that a heat shock protein represses cas-3 activation.

*These authors contributed equally to this work.In inflammatory central nervous system conditions such as multiple sclerosis, breakdown of the blood-brain barrier is a key event in lesion pathogenesis, predisposing to oedema, excitotoxicity, and ingress of plasma proteins and inflammatory cells. Recently, we showed that reactive astrocytes drive blood-brain barrier opening, via production of vascular endothelial growth factor A (VEGFA). Here, we now identify thymidine phosphorylase (TYMP; previously known as endothelial cell growth factor 1, ECGF1) as a second key astrocyte-derived permeability factor, which interacts with VEGFA to induce blood-brain barrier disruption. The two are co-induced NFB1-dependently in human astrocytes by the cytokine interleukin 1 beta (IL1B), and inactivation of Vegfa in vivo potentiates TYMP induction. In human central nervous system microvascular endothelial cells, VEGFA and the TYMP product 2-deoxy-D-ribose cooperatively repress tight junction proteins, driving permeability. Notably, this response represents part of a wider pattern of endothelial plasticity: 2-deoxy-D-ribose and VEGFA produce transcriptional programs encompassing angiogenic and permeability genes, and together regulate a third unique cohort. Functionally, each promotes proliferation and viability, and they cooperatively drive motility and angiogenesis. Importantly, introduction of either into mouse cortex promotes blood-brain barrier breakdown, and together they induce severe barrier disruption. In the multiple sclerosis model experimental autoimmune encephalitis, TYMP and VEGFA co-localize to reactive astrocytes, and correlate with blood-brain barrier permeability. Critically, blockade of either reduces neurologic deficit, blood-brain barrier disruption and pathology, and inhibiting both in combination enhances tissue preservation. Suggesting importance in human disease, TYMP and VEGFA both localize to reactive astrocytes in multiple sclerosis lesion samples. Collectively, these data identify TYMP as an astrocyte-derived permeability factor, and suggest TYMP and VEGFA together promote blood-brain barrier breakdown.

OBJECTIVE:To test the association between physical function and the social environment in multiple sclerosis (MS), we quantified personal social networks.METHODS:In this cross-sectional study, we analyzed data from two academic MS centers, with center one serving as a discovery group, and center two as the extension group. We performed a meta-analysis of the centers to extend the analysis. We used responses from a questionnaire to map the structure and health habits of participants’ social networks, and the NIH Patient-Reported Outcomes Measurement Information System (PROMIS) physical function scale (0-100, mean 50 for US general population) as the primary outcome. We applied multivariable models to test the association between network metrics and physical function.RESULTS:The discovery cohort included 263 MS patients: 81% were women, 96% non-Hispanic European, 78% relapsing MS, average age 50 (12.4) years, and mean disease duration 17 (12.3) years. The extension group included 163 patients, who were younger, more racially diverse, less physically disabled, and had shorter disease duration. In the meta-analysis, higher network constraint, a measure of tightly-bound networks, was associated with worse physical function (β=-0.163+0.047, p<0.001), while larger network effective size, a measure of clustered groups in the network, correlated with better physical function (β=0.134+0.046, p=0.003).CONCLUSIONS:Our study highlights personal networks as an important environmental factor associated with physical function in MS. Patients with close-knit networks had worse function than those with more open networks. Longitudinal studies are warranted to evaluate a causal relationship between network structure and physical impairment.

Since 2004, five drugs with new mechanisms of action have been approved by the US Food and Drug Administration for the treatment of relapsing forms of multiple sclerosis (MS). The expanded armamentarium of treatment options offers new opportunities for improved disease control and increased tolerability of medications, and also presents new safety concerns and monitoring requirements with which physicians must familiarize themselves. We review each of the newly approved agents-natalizumab, fingolimod, teriflunomide, dimethyl fumarate, and alemtuzumab-with regard to their mechanism of action, clinical trial data, safety and tolerability concerns, and monitoring requirements. We also review available data for promising agents that are currently in late-phase clinical trials, including daclizumab, ocrelizumab, and ofatumumab.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Progressive multifocal leukoencephalopathy (PML) is a rapidly progressive, often fatal viral infection of the brain without a known treatment. Recently, case reports have demonstrated survival from PML with therapies that improve cell-mediated immunity, including interleukin-7 (IL-7) or the chemokine receptor type 5 (CCR5) antagonist, maraviroc (MVC). We present the first known case of a patient with PML successfully treated with both IL-7 and MVC. A 63-year-old woman presented to our center with a 6-month history of progressive left hemiparesis. Extensive laboratory testing was negative except for a severe CD4 lymphocytopenia (140/μL). Serial brain MRIs done prior to presentation revealed an enlarging, non-enhancing T2-hyperintense lesion in the right fronto-parietal white matter. PML was confirmed through detection of the JC virus by PCR in the cerebrospinal fluid and by brain biopsy, and she was started on mirtazapine and mefloquine. She continued to deteriorate and was then given a course of recombinant IL-7. Though she remained clinically stable after IL-7 treatment and serum JCV PCR decreased from 1000 copies/mL to a nadir of 238 copies/mL, a repeat MRI 3 months later showed lesion enlargement. MVC was then initiated. Now, more than 2 years after initial presentation, she remains stable and serum JCV PCR is undetectable. This case demonstrates successful treatment of PML in a patient with idiopathic CD4 lymphocytopenia and highlights the potential benefits of IL-7 and MVC in the treatment of PML. Treatment with IL-7 and MVC led to clinical stability and improvement in JC virus titers.

Objective/BackgroundThe majority of multiple sclerosis patients experience impaired walking ability, which impacts quality of life. Timed 25-foot walk is commonly used to gauge gait impairment but results can be broadly variable. Objective biological markers that correlate closely with patients’ disability are needed. Diffusion tensor imaging, quantifying fiber tract integrity, might provide such information. In this project we analyzed relationships between timed 25-foot walk, conventional and diffusion tensor imaging magnetic resonance imaging markers.Design/MethodsA cohort of gait impaired multiple sclerosis patients underwent brain and cervical spinal cord magnetic resonance imaging. Diffusion tensor imaging mean diffusivity and fractional anisotropy were measured on the brain corticospinal tracts and spinal restricted field of vision at C2/3. We analyzed relationships between baseline timed 25-foot walk, conventional and diffusion tensor imaging magnetic resonance imaging markers.ResultsMultivariate linear regression analysis showed a statistically significant association between several magnetic resonance imaging and diffusion tensor imaging metrics and timed 25-foot walk: brain mean diffusivity corticospinal tracts (p = 0.004), brain corticospinal tracts axial and radial diffusivity (P = 0.004 and 0.02), grey matter volume (p = 0.05), white matter volume (p = 0.03) and normalized brain volume (P = 0.01). The linear regression model containing mean diffusivity corticospinal tracts and controlled for gait assistance was the best fit model (p = 0.004).ConclusionsOur results suggest an association between diffusion tensor imaging metrics and gait impairment, evidenced by brain mean diffusivity corticospinal tracts and timed 25-foot walk.