Analysis of RIM Expression and Function at Mouse Photoreceptor Ribbon Synapses.

RAB3A-interacting molecule (RIM) proteins are important regulators of transmitter release from active zones. At conventional chemical synapses, RIMs contribute substantially to vesicle priming and docking and their loss reduces the readily releasable pool of synaptic vesicles by up to 75%. The priming function of RIMs is mediated via the formation of a tripartite complex with Munc13 and RAB3A, which brings synaptic vesicles in close proximity to Ca channels and the fusion site and activates Munc13.

Rab Interacting Molecules 2 and 3 Directly Interact with the Pore-Forming Ca1.3 Ca Channel Subunit and Promote Its Membrane Expression.

Rab interacting molecules (RIMs) are multi-domain proteins that positively regulate the number of Ca channels at the presynaptic active zone (AZ). Several molecular mechanisms have been demonstrated for RIM-binding to components of the presynaptic Ca channel complex, the key signaling element at the AZ. Here, we report an interaction of the CB domain of RIM2α and RIM3γ with the C-terminus of the pore-forming α-subunit of Ca1.

The Role of Peripheral CNS-Directed Antibodies in Promoting Inflammatory CNS Demyelination.

In central nervous system (CNS) demyelinating disorders, such as multiple sclerosis (MS), neuromyelitis optica (NMO) and related NMO-spectrum disorders (NMO-SD), a pathogenic role for antibodies is primarily projected into enhancing ongoing CNS inflammation by directly binding to target antigens within the CNS. This scenario is supported at least in part, by antibodies in conjunction with complement activation in the majority of MS lesions and by deposition of anti-aquaporin-4 (AQP-4) antibodies in areas of astrocyte loss in patients with classical NMO. A currently emerging subgroup of AQP-4 negative NMO-SD patients expresses antibodies against myelin oligodendrocyte glycoprotein (MOG), again suggestive of their direct binding to CNS myelin.

Decrease in Aβ42 predicts dopa-resistant gait progression in early Parkinson disease.

Objective: This prospective observational study investigates the role of CSF biomarkers in predicting progression of dopa-resistant gait impairments in Parkinson disease (PD) in the first 36 months from diagnosis.

Methods: Quantitative gait analysis was carried out longitudinally using an instrumented walkway (GAITRite) in 108 people with PD and 130 age-matched controls. A subgroup of 44 people with PD underwent lumbar puncture from which a battery of CSF biomarkers was measured: β-amyloid 1-42 and 1-40 (Aβ42 and Aβ40), total and phosphorylated tau protein (t-tau/p-tau), and α-synuclein (αSyn).

Metabolic profiling of body fluids and multivariate data analysis.

Metabolome analyses of body fluids are challenging due pre-analytical variations, such as pre-processing delay and temperature, and constant dynamical changes of biochemical processes within the samples. Therefore, proper sample handling starting from the time of collection up to the analysis is crucial to obtain high quality samples and reproducible results. A metabolomics analysis is divided into 4 main steps: 1) Sample collection, 2) Metabolite extraction, 3) Data acquisition and 4) Data analysis.

The role of peripheral immune cells in the CNS in steady state and disease.

The CNS is protected by the immune system, including cells that reside directly within the CNS and help to ensure proper neural function, as well as cells that traffic into the CNS with disease. The CNS-resident immune system is comprised mainly of innate immune cells and operates under homeostatic conditions. These myeloid cells in the CNS parenchyma and at CNS-periphery interfaces are highly specialized but also extremely plastic cells that immediately react to any changes in CNS homeostasis and become reactive in the context of neurodegenerative disorders such as Alzheimer's disease or Parkinson's disease.

Transient Cnp expression by early progenitors causes Cre-Lox-based reporter lines to map profoundly different fates.

NG2 expressing oligodendroglial precursor cells are ubiquitous in the central nervous system and the only cell type cycling throughout life. Previous fate mapping studies have remained inconsistent regarding the question whether NG2 cells are capable of generating certain types of neurons. Here, we use CNP-Cre mice to map the fate of a sub-population of NG2 cells assumed to be close to differentiation.

Multicenter immunoassay validation of cerebrospinal fluid neurofilament light: a biomarker for neurodegeneration.

Aim: Neurofilament light (NfL) chain, a putative cerebrospinal fluid biomarker, can support neurodegenerative disease diagnosis and indicate disease severity and prognosis. Universal validation protocols when used to measure biomarkers can reduce pre and analytical laboratory variation, thus increasing end-user confidence in the consistency of validation data across sites.

Methodology: Here, a commercially available NfL ELISA (UmanDiagnostics, Umeå, Sweden) was validated in a multicentered setting using comprehensive newly developed standard operating procedures.

Novel Mouse Models of Methylmalonic Aciduria Recapitulate Phenotypic Traits with a Genetic Dosage Effect.

Methylmalonic aciduria (MMAuria), caused by deficiency of methylmalonyl-CoA mutase (MUT), usually presents in the newborn period with failure to thrive and metabolic crisis leading to coma or even death. Survivors remain at risk of metabolic decompensations and severe long term complications, notably renal failure and neurological impairment. We generated clinically relevant mouse models of MMAuria using a constitutive Mut knock-in (KI) allele based on the p.

TGFβ regulates persistent neuroinflammation by controlling Th1 polarization and ROS production via monocyte-derived dendritic cells.

Intracerebral levels of Transforming Growth Factor beta (TGFβ) rise rapidly during the onset of experimental autoimmune encephalomyelitis (EAE), a mouse model of Multiple Sclerosis (MS). We addressed the role of TGFβ responsiveness in EAE by targeting the TGFβ receptor in myeloid cells, determining that Tgfbr2 was specifically targeted in monocyte-derived dendritic cells (moDCs) but not in CNS resident microglia by using bone-marrow chimeric mice. TGFβ responsiveness in moDCs was necessary for the remission phase since LysM(Cre) Tgfbr2(fl/fl) mice developed a chronic form of EAE characterized by severe demyelination and extensive infiltration of activated moDCs in the CNS.

Interferon-beta signaling in retinal mononuclear phagocytes attenuates pathological neovascularization.

Age-related macular degeneration (AMD) is a leading cause of vision loss among the elderly. AMD pathogenesis involves chronic activation of the innate immune system including complement factors and microglia/macrophage reactivity in the retina. Here, we show that lack of interferon-β signaling in the retina accelerates mononuclear phagocyte reactivity and promotes choroidal neovascularization (CNV) in the laser model of neovascular AMD Complete deletion of interferon-α/β receptor (Ifnar) using Ifnar1(-/-) mice significantly enhanced early microglia and macrophage activation in lesion areas.

Novel genetic and neuropathological insights in neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP).

Introduction: Neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP) is caused by m.8993T>G/C mutations in the mitochondrial adenosine triphosphate synthase subunit 6 gene (MT-ATP6). Traditionally, heteroplasmy levels between 70% and 90% lead to NARP, and >90% result in Leigh syndrome.

Comparison of Different Matrices as Potential Quality Control Samples for Neurochemical Dementia Diagnostics.

Background: Assay-vendor independent quality control (QC) samples for neurochemical dementia diagnostics (NDD) biomarkers are so far commercially unavailable. This requires that NDD laboratories prepare their own QC samples, for example by pooling leftover cerebrospinal fluid (CSF) samples.

Objective: To prepare and test alternative matrices for QC samples that could facilitate intra- and inter-laboratory QC of the NDD biomarkers.

CD14 is a key organizer of microglial responses to CNS infection and injury.

Microglia, innate immune cells of the CNS, sense infection and damage through overlapping receptor sets. Toll-like receptor (TLR) 4 recognizes bacterial lipopolysaccharide (LPS) and multiple injury-associated factors. We show that its co-receptor CD14 serves three non-redundant functions in microglia.

Self-renewing resident arterial macrophages arise from embryonic CX3CR1(+) precursors and circulating monocytes immediately after birth.

Resident macrophages densely populate the normal arterial wall, yet their origins and the mechanisms that sustain them are poorly understood. Here we use gene-expression profiling to show that arterial macrophages constitute a distinct population among macrophages. Using multiple fate-mapping approaches, we show that arterial macrophages arise embryonically from CX3CR1(+) precursors and postnatally from bone marrow-derived monocytes that colonize the tissue immediately after birth.

Glatiramer acetate treatment negatively regulates type I interferon signaling.

Objective: Glatiramer acetate (GA; Copaxone), a disease-modifying therapy for multiple sclerosis (MS), promotes development of anti-inflammatory (M2, type II) monocytes that can direct differentiation of regulatory T cells. We investigated the innate immune signaling pathways that participate in GA-mediated M2 monocyte polarization.

Methods: Monocytes were isolated from myeloid differentiation primary response gene 88 (MyD88)-deficient, Toll-IL-1 receptor domain-containing adaptor inducing interferon (IFN)-β (TRIF)-deficient, IFN-α/β receptor subunit 1 (IFNAR1)-deficient, and wild-type (WT) mice and human peripheral blood.

Myeloid cells in Alzheimer's disease: culprits, victims or innocent bystanders?

Several recent genome-wide association studies (GWAS) in patients with neurodegenerative disorders have shed new light on the brain immune system, suggesting that it plays a pivotal role in disease pathogenesis. Mononuclear phagocytes are blatantly involved in Alzheimer's disease (AD) of the central nervous system (CNS), but the specific functions of resident microglia, perivascular or meningeal macrophages, and circulating myeloid cells have not yet been fully resolved. Next-generation sequencing, high-throughput immune profiling technologies, and novel genetic tools have recently revolutionized the characterization of innate immune responses during AD.

Adult-onset autosomal dominant centronuclear myopathy due to BIN1 mutations.

Centronuclear myopathies are congenital muscle disorders characterized by type I myofibre predominance and an increased number of muscle fibres with nuclear centralization. The severe neonatal X-linked form is due to mutations in MTM1, autosomal recessive centronuclear myopathy with neonatal or childhood onset results from mutations in BIN1 (amphiphysin 2), and dominant cases were previously associated to mutations in DNM2 (dynamin 2). Our aim was to determine the genetic basis and physiopathology of patients with mild dominant centronuclear myopathy without mutations in DNM2.

Progressive replacement of embryo-derived cardiac macrophages with age.

Cardiac macrophages (cMΦ) are critical for early postnatal heart regeneration and fibrotic repair in the adult heart, but their origins and cellular dynamics during postnatal development have not been well characterized. Tissue macrophages can be derived from embryonic progenitors or from monocytes during inflammation. We report that within the first weeks after birth, the embryo-derived population of resident CX3CR1(+) cMΦ diversifies into MHCII(+) and MHCII(-) cells.

Recovery of diaphragm function following mechanical ventilation in a rodent model.

Background: Mechanical ventilation (MV) induces diaphragmatic muscle fiber atrophy and contractile dysfunction (ventilator induced diaphragmatic dysfunction, VIDD). It is unknown how rapidly diaphragm muscle recovers from VIDD once spontaneous breathing is restored. We hypothesized that following extubation, the return to voluntary breathing would restore diaphragm muscle fiber size and contractile function using an established rodent model.

Sedation using propofol induces similar diaphragm dysfunction and atrophy during spontaneous breathing and mechanical ventilation in rats.

Background: Mechanical ventilation is crucial for patients with respiratory failure. The mechanical takeover of diaphragm function leads to diaphragm dysfunction and atrophy (ventilator-induced diaphragmatic dysfunction), with an increase in oxidative stress as a major contributor. In most patients, a sedative regimen has to be initiated to allow tube tolerance and ventilator synchrony.

Neuron-specific alterations in signal transduction pathways associated with Alzheimer's disease.

The hallmarks of sporadic Alzheimer's disease (AD) are extracellular amyloid deposits, intracellular neurofibrillary tangles (NFTs), and neuronal death. Hyperphosphorylation of tau is a key factor in the generation of NFTs. Mitogen activated protein kinase 1 (MAPK1) and protein kinase C beta (PRKCB) are thought to play a role in hyperphosphorylation, and PRCKB is thought to be involved in hypoxic stress and vascular dysfunction, and to trigger MAPK phosphorylation pathways.

Myofibrillar myopathies: a clinical and myopathological guide.

Myofibrillar myopathies (MFMs) are histopathologically characterized by desmin-positive protein aggregates and myofibrillar degeneration. Because of the marked phenotypic and pathomorphological variability, establishing the diagnosis of MFM can be a challenging task. While MFMs are partly caused by mutations in genes encoding for extramyofibrillar proteins (desmin, alphaB-crystallin, plectin) or myofibrillar proteins (myotilin, Z-band alternatively spliced PDZ-containing protein, filamin C, Bcl-2-associated athanogene-3, four-and-a-half LIM domain 1), a large number of these diseases are caused by still unresolved gene defects.