Search

Purpose Clinically evaluate the noninferiority of a custom virtual reality (VR) perimetry system when compared to a clinically and routinely used perimeter on both healthy subjects and glaucoma patients. Methods We use a custom-designed VR perimetry system tailored for visual field testing. The system uses Oculus Quest VR headset (Facebook Technologies, LLC, Bern, Switzerland), that includes a clicker for participant response feedback. A prospective, single center, study was conducted at the Department of Ophthalmology of the Bern University Hospital (Bern, Switzerland) for 12 months. Of the 114 participants recruited 70 subjects (36 healthy and 34 glaucoma patients with early to moderate visual field loss) were included in the study. Participants underwent perimetry tests on an Octopus 900 (Haag-Streit, K��niz, Switzerland) as well as on the custom VR perimeter. In both cases, standard dynamic strategy (DS) was used in conjunction with the G testing pattern. Collected visual fields (VFs) from both devices were then analyzed and compared. Results High mean defect (MD) correlations between the two systems (Spearman, �� ��� 0.75) were obtained. The VR system was found to slightly underestimate VF defects in glaucoma subjects (1.4 dB). No significant bias was found with respect to eccentricity or subject age. On average, a similar number of stimuli presentations per VF was necessary when measuring glaucoma patients and healthy subjects. Conclusions This study demonstrates that a clinically used perimeter and the proposed VR perimetry system have comparable performances with respect to a number of perimetry parameters in healthy and glaucoma patients with early to moderate visual field loss. Translational Relevance This suggests that VR perimeters have the potential to assess VFs with high enough confidence, whereby alleviating challenges in current perimetry practices by providing a portable and more accessible visual field test.

Bacillus subtilis spore inactivation mechanisms under low energy electron beam (LEEB) and high energy electron beam (HEEB) treatment were investigated using seven mutants lacking specific DNA repair mechanisms. The results showed that most of the DNA repair-deficient mutants, including ΔrecA, ΔKu ΔligD, Δexo Δnfo, ΔuvrAB and ΔsbcDC, had reduced resistances towards electron beam (EB) treatments at all investigated energy levels (80 keV, 200 keV and 10 MeV) compared to their wild type. This result suggested DNA damage was induced during EB treatments. The mutant lacking recA showed the lowest resistance, followed by the mutant lacking Ku and ligD. These findings indicated that recA, Ku and ligD and their associated DNA repair mechanisms, namely, homologous recombination and non-homologous end joining, play important roles in spore survival under EB treatment. Furthermore, exoA, nfo, uvrAB, splB, polY1 and polY2, which are involved in nucleotide damage repair/removal, showed different levels of effects on spore resistance under EB treatment. Finally, the results suggested that HEEB and LEEB inactivate B. subtilis spores through similar mechanisms. This research will provide a better understanding of how EB technologies inactivate B. subtilis spores and will contribute to the application of these technologies as a non-thermal, gentle spore control approach., Food Microbiology, 87, ISSN:0740-0020, ISSN:1095-9998

INTRODUCTION: The cerebral cortex is responsible for higher-order functions in the nervous system and has undergone substantial expansion in size in primates. The development of the forebrain, including the assembly of the expanded human cerebral cortex, is a lengthy process that involves the diversification and expansion of neural progenitors, the generation and positioning of layer-specific glutamatergic neurons, the cellular migration of γ-aminobutyric acid (GABA)-ergic neurons, and the formation and maturation of glial cells. Disruption of these cellular events by either genetic or environmental factors can lead to neurodevelopmental disease, including autism spectrum disorders and intellectual disability. RATIONALE: Human forebrain development is, to a large extent, inaccessible for cellular-level study, direct functional investigation, or manipulation. The lack of availability of primary brain tissue samples—in particular, at later stages—as well as the limitations of conventional in vitro cellular models have precluded a detailed mechanistic understanding of corticogenesis in healthy and disease states. Therefore, tracking epigenetic changes in specific forebrain cell lineages over long time periods, has the potential to unravel the molecular programs that underlie cell specification in the human cerebral cortex and, by temporally mapping disease risk onto these changes, to identify cell types and periods of increased disease susceptibility. RESULTS: We used three-dimensional (3D) directed differentiation of human pluripotent stem cells into dorsal and ventral forebrain domains and applied the assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) in combination with RNA-sequencing (RNA-seq) to map the epigenetic and gene expression signatures of neuronal and glial cell lineages over 20 months in vitro. We show, through direct comparison with primary brain tissue from our study and several epigenetic datasets, that human stem cell-derived 3D forebrain organoids recapitulated in vivo chromatin accessibility patterns over time. We then integrated these data to discover putative enhancer-gene linkages and lineage-specific transcription factor regulators, including a diverse repertoire of factors that may control cortical specification. We validated protein expression of some of these transcription factors using immunofluorescence, confirming cellular and temporal dynamics in both primary tissue and forebrain organoids. Next, we used this resource to map genes and genetic variants associated with schizophrenia and autism spectrum disorders to distinct accessibility patterns to reveal cell types and periods of susceptibility. Last, we identified a wave of chromatin remodeling during cortical neurogenesis, during which a quarter of regulatory regions are active, and then highlighted transcription factors that may drive these developmental changes. CONCLUSION: Using long-term 3D neural differentiation of stem cells as well as primary brain tissue samples, we found that organoids intrinsically undergo chromatin state transitions in vitro that are closely related to human forebrain development in vivo. Leveraging this platform, we identified epigenetic alterations putatively driven by specific transcription factors and discovered a dynamic period of chromatin remodeling during human cortical neurogenesis. Finally, we nominated several key transcription factors that may coordinate over time to drive these changes and mapped cell type-specific disease-associated variation over time and in specific cell types.

The development of the nervous system involves a coordinated succession of events including the migration of GABAergic (γ-aminobutyric-acid-releasing) neurons from ventral to dorsal forebrain and their integration into cortical circuits. However, these interregional interactions have not yet been modelled with human cells. Here we generate three-dimensional spheroids from human pluripotent stem cells that resemble either the dorsal or ventral forebrain and contain cortical glutamatergic or GABAergic neurons. These subdomain-specific forebrain spheroids can be assembled in vitro to recapitulate the saltatory migration of interneurons observed in the fetal forebrain. Using this system, we find that in Timothy syndrome-a neurodevelopmental disorder that is caused by mutations in the CaV1.2 calcium channel-interneurons display abnormal migratory saltations. We also show that after migration, interneurons functionally integrate with glutamatergic neurons to form a microphysiological system. We anticipate that this approach will be useful for studying neural development and disease, and for deriving spheroids that resemble other brain regions to assemble circuits in vitro.

The process of aging is multifactorial and therefore single interventions may be unlikely to attenuate the myriad pathologies. Plasma contains many beneficial factors which have been shown in animal models to ameliorate multiple age-related deficits across varied organ systems, including the brain. We demonstrated that human plasma from young 18-22-year-old donors reverses age-related cognitive decline and enhances hippocampal neurogenesis and cell survival in aged immunocompromised mice, while plasma from aged individuals (62-68 years old) has detrimental effects in young mice. Utilizing cell-based assays we identified a human plasma fraction (PF) which enhanced neuronal outgrowth and synaptic connectivity. We demonstrate that PF administration provides benefits beyond those observed with whole plasma treatment, resulting in decreased brain inflammation, increased synaptic density and neuronal activation. We evaluated longitudinal treatment of PF and observed no depletion in stem cell populations while maintaining an enhanced level of neurogenesis. We examined PF in an α-synuclein mouse model of Parkinson’s disease, where treatment significantly reversed functional, inflammatory, and neuronal deficits. To further our understanding of interplay between multiple mechanisms inducing neurogenesis, we examined the effect of exercise on PF treated mice and observed a synergistic increase in neurogenesis. Proteomic analysis of mouse plasma following PF treatment demonstrates differential protein levels compared to running or the combination of running and PF, suggesting that PF is mechanistically different from the effect of running. In summary, we demonstrate that PF is a multifactorial and multimodal, clinically-relevant, intervention for the treatment of global changes induced by aging.

In the developing brain, neurons expressing VEGF-A and blood vessels grow in close apposition, but many of the molecular pathways regulating neuronal VEGF-A and neurovascular system development remain to be deciphered. Here, we show that miR-9 links neurogenesis and angiogenesis through the formation of neurons expressing VEGF-A. We found that miR-9 directly targets the transcription factors TLX and ONECUTs to regulate VEGF-A expression. miR-9 inhibition leads to increased TLX and ONECUT expression, resulting in VEGF-A overexpression. This untimely increase of neuronal VEGF-A signal leads to the thickening of blood vessels at the expense of the normal formation of the neurovascular network in the brain and retina. Thus, this conserved transcriptional cascade is critical for proper brain development in vertebrates. Because of this dual role on neural stem cell proliferation and angiogenesis, miR-9 and its downstream targets are promising factors for cellular regenerative therapy following stroke and for brain tumor treatment.

Recombinant adeno-associated viruses (rAAVs) are commonly used vehicles for in vivo gene transfer. However, the tropism repertoire of naturally occurring AAVs is limited, prompting a search for novel AAV capsids with desired characteristics. Here we describe a capsid selection method, called Cre recombination-based AAV targeted evolution (CREATE), that enables the development of AAV capsids that more efficiently transduce defined Cre-expressing cell populations in vivo. We use CREATE to generate AAV variants that efficiently and widely transduce the adult mouse central nervous system (CNS) after intravenous injection. One variant, AAV-PHP.B, transfers genes throughout the CNS with an efficiency that is at least 40-fold greater than that of the current standard, AAV9 (refs. 14,15,16,17), and transduces the majority of astrocytes and neurons across multiple CNS regions. In vitro, it transduces human neurons and astrocytes more efficiently than does AAV9, demonstrating the potential of CREATE to produce customized AAV vectors for biomedical applications.

Objective: Ganglioside-induced differentiation associated-protein 1 ( GDAP1 ) mutations are commonly associated with autosomal recessive Charcot-Marie-Tooth (ARCMT) neuropathy; however, in rare instances, they also lead to autosomal dominant Charcot-Marie-Tooth (ADCMT). We aimed to investigate the frequency of disease-causing heterozygous GDAP1 mutations in ADCMT and their associated phenotype. Methods: We performed mutation analysis in a large cohort of ADCMT patients by means of bidirectional sequencing of coding regions and exon-intron boundaries of GDAP1 . Intragenic GDAP1 deletions were excluded using an allele quantification assay. We confirmed the pathogenic character of one sequence variant by in vitro experiments assaying mitochondrial morphology and function. Results: In 8 Charcot-Marie-Tooth disease (CMT) families we identified 4 pathogenic heterozygous GDAP1 mutations, 3 of which are novel. Three of the mutations displayed reduced disease penetrance. Disease onset in the affected individuals was variable, ranging from early childhood to adulthood. Disease progression was slow in most patients and overall severity milder than typically seen in autosomal recessive GDAP1 mutations. Electrophysiologic changes are heterogeneous but compatible with axonal neuropathy in the majority of patients. Conclusions: With this study, we broaden the phenotypic and genetic spectrum of autosomal dominant GDAP1 -associated neuropathies. We show that patients with dominant GDAP1 mutations may display clear axonal CMT, but may also have only minimal clinical and electrophysiologic abnormalities. We demonstrate that cell-based functional assays can be reliably used to test the pathogenicity of unknown variants. We discuss the implications of phenotypic variability and the reduced penetrance of autosomal dominant GDAP1 mutations for CMT diagnostic testing and counseling.

Charcot-Marie-Tooth disease (CMT) caused by mutations in the ganglioside-induced differentiation-associated protein 1 (GDAP1) gene is characterized by a spectrum of phenotypes. Recurrent nonsense mutations (Q163X and S194X) showing regional distribution segregate with an early onset, severe course of recessive CMT disease with early loss of ambulancy. Missense mutations in GDAP1 have been reported in sporadic CMT cases with variable course of disease, among them the recurrent L239F missense GDAP1 mutation occurring in the European population. Finally, some GDAP1 mutations are associated with a mild form of CMT inherited as an autosomal dominant trait. In this study, we characterize the CMT phenotype in one Polish family with recessive trait of inheritance at the clinical, electrophysiological, morphological, cellular, and genetic level associated with a new Gly327Asp mutation in the GDAP1 gene. In spite of the nature of Gly327Asp mutation (missense), the CMT phenotype associated with this variant may be characterized as an early onset, severe axonal neuropathy, with severe skeletal deformities. The mutation lies within the transmembrane domain of GDAP1 and interferes with the mitochondrial targeting of the protein, similar to the loss of the domain in the previously reported Q163X and S194X mutations. We conclude that the loss of mitochondrial targeting is associated with a severe course of disease. Our study shows that clinical outcome of CMT disease caused by mutations in the GDAP1 gene cannot be predicted solely on the basis of genetic results (missense/nonsense mutations).

The human cerebral cortex develops through an elaborate succession of cellular events that, when disrupted, can lead to neuropsychiatric disease. The ability to reprogram somatic cells into pluripotent cells that can be differentiated in vitro provides a unique opportunity to study normal and abnormal corticogenesis. Here, we present a simple and reproducible 3D culture approach for generating a laminated cerebral cortex-like structure, named human cortical spheroids (hCSs), from pluripotent stem cells. hCSs contain neurons from both deep and superficial cortical layers and map transcriptionally to in vivo fetal development. These neurons are electrophysiologically mature, display spontaneous activity, are surrounded by nonreactive astrocytes and form functional synapses. Experiments in acute hCS slices demonstrate that cortical neurons participate in network activity and produce complex synaptic events. These 3D cultures should allow a detailed interrogation of human cortical development, function and disease, and may prove a versatile platform for generating other neuronal and glial subtypes in vitro.

Summary There is significant need to develop physiologically relevant models for investigating human astrocytes in health and disease. Here, we present an approach for generating astrocyte lineage cells in a three-dimensional (3D) cytoarchitecture using human cerebral cortical spheroids (hCSs) derived from pluripotent stem cells. We acutely purified astrocyte-lineage cells from hCSs at varying stages up to 20 months in vitro using immunopanning and cell sorting and performed high-depth bulk and single-cell RNA sequencing to directly compare them to purified primary human brain cells. We found that hCS-derived glia closely resemble primary human fetal astrocytes and that, over time in vitro , they transition from a predominantly fetal to an increasingly mature astrocyte state. Transcriptional changes in astrocytes are accompanied by alterations in phagocytic capacity and effects on neuronal calcium signaling. These findings suggest that hCS-derived astrocytes closely resemble primary human astrocytes and can be used for studying development and modeling disease.

Mutations in the mitochondrial fission factor GDAP1 are associated with severe peripheral neuropathies, but why the CNS remains unaffected is unclear. Using a Gdap1−/− mouse, Niemann et al. demonstrate that a CNS-expressed Gdap1 paralogue changes its subcellular localisation under oxidative stress conditions to also act as a mitochondrial fission factor., The ganglioside-induced differentiation-associated protein 1 (GDAP1) is a mitochondrial fission factor and mutations in GDAP1 cause Charcot–Marie–Tooth disease. We found that Gdap1 knockout mice (Gdap1−/−), mimicking genetic alterations of patients suffering from severe forms of Charcot–Marie–Tooth disease, develop an age-related, hypomyelinating peripheral neuropathy. Ablation of Gdap1 expression in Schwann cells recapitulates this phenotype. Additionally, intra-axonal mitochondria of peripheral neurons are larger in Gdap1−/− mice and mitochondrial transport is impaired in cultured sensory neurons of Gdap1−/− mice compared with controls. These changes in mitochondrial morphology and dynamics also influence mitochondrial biogenesis. We demonstrate that mitochondrial DNA biogenesis and content is increased in the peripheral nervous system but not in the central nervous system of Gdap1−/− mice compared with control littermates. In search for a molecular mechanism we turned to the paralogue of GDAP1, GDAP1L1, which is mainly expressed in the unaffected central nervous system. GDAP1L1 responds to elevated levels of oxidized glutathione by translocating from the cytosol to mitochondria, where it inserts into the mitochondrial outer membrane. This translocation is necessary to substitute for loss of GDAP1 expression. Accordingly, more GDAP1L1 was associated with mitochondria in the spinal cord of aged Gdap1−/− mice compared with controls. Our findings demonstrate that Charcot–Marie–Tooth disease caused by mutations in GDAP1 leads to mild, persistent oxidative stress in the peripheral nervous system, which can be compensated by GDAP1L1 in the unaffected central nervous system. We conclude that members of the GDAP1 family are responsive and protective against stress associated with increased levels of oxidized glutathione.

Mitochondria and peroxisomes can be fragmented by the process of fission. The fission machineries of both organelles share a set of proteins. GDAP1 is a tail-anchored protein of mitochondria and induces mitochondrial fragmentation. Mutations in GDAP1 lead to Charcot-Marie-Tooth disease (CMT), an inherited peripheral neuropathy, and affect mitochondrial dynamics. Here, we show that GDAP1 is also targeted to peroxisomes mediated by the import receptor Pex19. Knockdown of GDAP1 leads to peroxisomal elongation that can be rescued by re-expressing GDAP1 and by missense mutated forms found in CMT patients. GDAP1-induced peroxisomal fission is dependent on the integrity of its hydrophobic domain 1, and on Drp1 and Mff, as is mitochondrial fission. Thus, GDAP1 regulates mitochondrial and peroxisomal fission by a similar mechanism. However, our results reveal also a more critical role of the amino-terminal GDAP1 domains, carrying most CMT-causing mutations, in the regulation of mitochondrial compared to peroxisomal fission.

Recombinant adeno-associated viruses (rAAVs) are commonly used vehicles for in vivo gene transfer. However, the tropism repertoire of naturally occurring AAVs is limited, prompting the development of novel AAV capsids with more desirable transduction characteristics. We have developed a capsid selection method, called Cre-recombination-based AAV targeted evolution (CREATE), that enables the identification of AAV capsids that more efficiently transduce defined cell populations in vivo (Deverman et al. in press, Nature Biotechnology). We generated AAV capsid libraries and used CREATE to identify variants that cross the blood brain barrier and efficiently and widely transduce astrocytes in the mouse central nervous system (CNS) after intravenous injection. One variant, AAVPHP. B, transfers genes throughout the adult CNS with an efficiency that is 40- to 92-fold greater (depending on the CNS region) than that of the current standard, AAV9. It transduces the majority of astrocytes and neurons across multiple CNS regions, and in vitro, it transduces human neurons and astrocytes more efficiently than does AAV9. We are now evolving AAV-PHP.B for even greater transduction of specific CNS cell types as a means to both develop more effective vectors and to gain insight into the mechanism of enhanced transduction. Our identification of AAV-PHP.B and several other enhanced vectors after only two rounds of selection establishes CREATE as a powerful method to customize AAV vectors for biomedical applications.

Mutations in the ganglioside-induced differentiation associated protein 1 (GDAP1) cause severe peripheral motor and sensory neuropathies called Charcot-Marie-Tooth disease. GDAP1 expression induces fission of mitochondria and peroxisomes by a currently elusive mechanism, while disease causing mutations in GDAP1 impede the protein’s role in mitochondrial dynamics. In silico analysis reveals sequence similarities of GDAP1 to glutathione S-transferases (GSTs). However, a proof of GST activity and its possible impact on membrane dynamics are lacking to date. Using recombinant protein, we demonstrate for the first time theta-class-like GST activity for GDAP1, and it’s activity being regulated by the C-terminal hydrophobic domain 1 (HD1) of GDAP1 in an autoinhibitory manner. Moreover, we show that the HD1 amphipathic pattern is required to induce membrane dynamics by GDAP1. As both, fission and GST activities of GDAP1, are critically dependent on HD1, we propose that GDAP1 undergoes a molecular switch, turning from a pro-fission active to an auto-inhibited inactive conformation.

We find that, in a linear model, the James-Stein estimator, which dominates the maximum-likelihood estimator in terms of its in-sample prediction error, can perform poorly compared to the maximum-likelihood estimator in out-of-sample prediction. We give a detailed analysis of this phenomenon and discuss its implications. When evaluating the predictive performance of estimators, we treat the regressor matrix in the training data as fixed, i.e., we condition on the design variables. Our findings contrast those obtained by Baranchik (1973, Ann. Stat. 1:312-321) and, more recently, by Dicker (2012, arXiv:1102.2952) in an unconditional performance evaluation.

Eine systematische Analyse der charakteristischen Elemente der Machtposition organschaftlicher Vertretungsorgane, die als Grund einer Untreuestrafbarkeit angefuhrt werden kann, ergibt, dass der Begriffsinhalt des Tatbestandsmerkmals der Befugnis nicht auf die Vertretungsmacht iSd Stellvertretungsrechts beschrankt ist. Versteht man das Tatbestandsmerkmal als Ausdruck einer generellen Machtposition, so lassen sich die vielfaltigen Aspekte eines Mangels an Vertretungsmacht auch in strafrechtlicher Hinsicht sachgerecht erfassen. Eine Person ist „befugt“ zu handeln, wenn ihr bereits im Zeitpunkt des Tatigwerdens die Macht zukommt, eine Rechtswirkung im Vermogen des Machtgebers herbeizufuhren.

Das Gefahrenpotential eines Taters mit unbeschrankbarer Vertretungsmacht wurde dahingehend charakterisiert, dass dieser typischerweise mehr „kann“ als er „darf“263. Wahrend die Ausfuhrungen im vorigen Kapitel der Determination seines „Konnens“ im Ausenverhaltnis gewidmet waren, gilt es im Folgenden das „Durfen“ im Innenverhaltnis naher zu prazisieren.

Die Untreue ist eine zivilrechtliche vorbestimmte Materie. Dies kann nach den vorstehenden Ausfuhrungen als unbestritten vorausgesetzt werden.