Dravet syndrome patient‐derived neurons suggest a novel epilepsy mechanism

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99647/1/ana23897.pd

Early-branching gut fungi possess a large, comprehensive array of biomass-degrading enzymes

available in PMC 2016 November 07The fungal kingdom is the source of almost all industrial enzymes in use for lignocellulose bioprocessing. We developed a systems-level approach that integrates transcriptomic sequencing, proteomics, phenotype, and biochemical studies of relatively unexplored basal fungi. Anaerobic gut fungi isolated from herbivores produce a large array of biomass-degrading enzymes that synergistically degrade crude, untreated plant biomass and are competitive with optimized commercial preparations from Aspergillus and Trichoderma. Compared to these model platforms, gut fungal enzymes are unbiased in substrate preference due to a wealth of xylan-degrading enzymes. These enzymes are universally catabolite-repressed and are further regulated by a rich landscape of noncoding regulatory RNAs. Additionally, we identified several promising sequence-divergent enzyme candidates for lignocellulosic bioprocessing.United States. Dept. of Energy. Office of Science (Biological and Environmental Research (BER) program)United States. Department of Energy (DOE Grant DE-SC0010352)United States. Department of Agriculture (Award 2011-67017-20459)Institute for Collaborative Biotechnologies (grant W911NF-09-0001

Implementation and evaluation of a Project ECHO telementoring program for the Namibian HIV workforce.

BACKGROUND: The Namibian Ministry of Health and Social Services (MoHSS) piloted the first HIV Project ECHO (Extension for Community Health Outcomes) in Africa at 10 clinical sites between 2015 and 2016. Goals of Project ECHO implementation included strengthening clinical capacity, improving professional satisfaction, and reducing isolation while addressing HIV service challenges during decentralization of antiretroviral therapy. METHODS: MoHSS conducted a mixed-methods evaluation to assess the pilot. Methods included pre/post program assessments of healthcare worker knowledge, self-efficacy, and professional satisfaction; assessment of continuing professional development (CPD) credit acquisition; and focus group discussions and in-depth interviews. Analysis compared the differences between pre/post scores descriptively. Qualitative transcripts were analyzed to extract themes and representative quotes. RESULTS: Knowledge of clinical HIV improved 17.8% overall (95% confidence interval 12.2-23.5%) and 22.3% (95% confidence interval 13.2-31.5%) for nurses. Professional satisfaction increased 30 percentage points. Most participants experienced reduced professional isolation (66%) and improved CPD credit access (57%). Qualitative findings reinforced quantitative results. Following the pilot, the Namibia MoHSS Project ECHO expanded to over 40 clinical sites by May 2019 serving more than 140 000 people living with HIV. CONCLUSIONS: Similar to other Project ECHO evaluation results in the United States of America, Namibia's Project ECHO led to the development of ongoing virtual communities of practice. The evaluation demonstrated the ability of the Namibia HIV Project ECHO to improve healthcare worker knowledge and satisfaction and decrease professional isolation

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

The role of sodium channel alpha and beta subunits in myelinating glia and demyelinating disorders.

Multiple sclerosis (MS) is a demyelinating inflammatory disease of the central nervous system (CNS) in which patients experience a variety of neurological symptoms resulting from demyelination, axonal degeneration and axonal loss leading to conduction block or aberrant conduction. Voltage-gated sodium channels (VGSCs) have been implicated in the pathogenesis of MS and its animal model, Experimental Allergic Encephalomyelitis (EAE). We previously generated a Scn2b (VGSC β2) null mouse which exhibits a 40-50% decrease in neuronal VGSC cell surface expression. We hypothesized that Scn2b deletion would result in neuroprotection in EAE due to a decrease in excitotoxicity. The goal of this thesis was to determine the role of VGSCs in CNS demyelinating disease and myelinating glia using three different systems: Scn2b null mice, human MS brain, and cultured rat oligodendrocytes. Scn2b deletion led to improved clinical outcome in the EAE model, with mice displaying less severe clinical symptoms, decreases in lethality, and reductions in axonal loss, degeneration and demyelination. In EAE, these mice also displayed alterations in subcellular localization and protein expression levels of the VGSC α subunit Nav1.1, a channel which has not been studied previously in demyelinating disease. We then translated these experiments to the study of post-mortem human brain. MS brain displayed increased Nav1.1 protein levels in white and grey matter and changes in expression of β subunits in glia as compared to control brain. Finally, we examined the expression of VGSC α and β subunits in cultured rat oligodendrocytes at two stages of differentiation. These cells displayed differential expression of α and β subunits, with VGSC α, β1 and β3 subunits expressed at both stages while β2 and β4 were expressed at low levels. To summarize, the results presented in this thesis implicate VGSC β2 and Nav1.1 subunits in the pathogenesis of CNS demyelinating disease in both human and mouse, and suggest roles for VGSC α and β subunits in myelinating glial cell precursors. VGSC β2 and Nav1.1 subunits may also offer novel targets for the development of therapeutics for the treatment of MS.Ph.D.Cellular & Molecular BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/64629/1/homalley_1.pd

Conduction Block in PMP22 Deficiency

Patients with PMP22 deficiency present with focal sensory and motor deficits when peripheral nerves are stressed by mechanical force. It has been hypothesized that these focal deficits are due to mechanically induced conduction block (CB). To test this hypothesis, we induced 60–70% CB (defined by electrophysiological criteria) by nerve compression in an authentic mouse model of hereditary neuropathy with liability to pressure palsies (HNPP) with an inactivation of one of the two pmp22 alleles ( pmp22 +/− ). Induction time for the CB was significantly shorter in pmp22 +/− mice than that in pmp22 +/+ mice. This shortened induction was also found in myelin-associated glycoprotein knock-out mice, but not in the mice with deficiency of myelin protein zero, a major structural protein of compact myelin. Pmp22 +/− nerves showed intact tomacula with no segmental demyelination in both noncompressed and compressed conditions, normal molecular architecture, and normal concentration of voltage-gated sodium channels by [ 3 H]-saxitoxin binding assay. However, focal constrictions were observed in the axonal segments enclosed by tomacula, a pathological hallmark of HNPP. The constricted axons increase axial resistance to action potential propagation, which may hasten the induction of CB in Pmp22 deficiency. Together, these results demonstrate that a function of Pmp22 is to protect the nerve from mechanical injury

A functional null mutation of **SCN1B** in a patient with Dravet syndrome

Dravet syndrome (also called Severe Myoclonic Epilepsy of Infancy) is one of the most severe forms of childhood epilepsy. Most patients have heterozygous mutations in SCN1A, encoding voltage-gated sodium channel Na(v)1.1 α subunits. Sodium channels are modulated by β1 subunits, encoded by SCN1B, a gene also linked to epilepsy. Here we report the first patient with Dravet Syndrome associated with a recessive mutation in SCN1B (p.R125C). Biochemical characterization of p.R125C in a heterologous system demonstrated little to no cell surface expression despite normal total cellular expression. This occurred regardless of co-expression of Na(v)1.1 α subunits. Because the patient was homozygous for the mutation, these data suggest a functional SCN1B null phenotype. To understand the consequences of the lack of β1 cell surface expression in vivo, hippocampal slice recordings were performed in Scn1b(−/−) vs. Scn1b(+/+) mice. Scn1b(−/−) CA3 neurons fired evoked action potentials with a significantly higher peak voltage and significantly greater amplitude compared to wildtype. However, in contrast to the Scn1a(+/−) model of Dravet syndrome, we found no measurable differences in sodium current density in acutely dissociated CA3 hippocampal neurons. While Scn1b(−/−) mice seize spontaneously, the seizure susceptibility of Scn1b(+/−) mice was similar to wildtype, suggesting that, like the parents of this patient, one functional SCN1B allele is sufficient for normal control of electrical excitability. We conclude that SCN1B p.R125C is an autosomal recessive cause of Dravet syndrome through functional gene inactivation

Constitutively active STAT6 predisposes toward a lymphoproliferative disorder

Signal transducer and activator of transcription 6 (STAT6) is critical for IL-4 and IL-13 responses, and necessary for the normal development of Th2 cells. We previously generated mice that express a constitutively active STAT6 (STAT6VT) under control of the CD2 locus control region, which directs expression to the T-cell compartment. We now describe that a small proportion of these mice (∼5%) develop a spontaneous lymphoproliferative disease (LPD) that results in dramatic splenomegaly. The cell populations observed in the LPD spleens can be divided into 2 categories, those that are composed of mixed lineage cells and those that are predominantly T cells with a phenotype similar to that in autoimmune lymphoproliferative syndrome (ALPS) patients. These data suggest that while active STAT6 is not a transforming factor, expression in T cells predisposes toward the development of lymphoproliferative disorders