TFEB and TFE3 (TFEB/3), key regulators of lysosomal biogenesis and autophagy, play diverse roles depending on cell type. This study highlights a hitherto unrecognized role of TFEB/3 crucial for peripheral nerve repair. Specifically, they promote the generation of progenitor-like repair Schwann cells after axonal injury.
View Article and Find Full Text PDFThe treatment of depressive episodes is well established, with clearly demonstrated effectiveness of antidepressants and psychotherapies. However, more than one-third of depressed patients do not respond to treatment. Identifying the brain structural basis of treatment-resistant depression could prevent useless pharmacological prescriptions, adverse events, and lost therapeutic opportunities.
View Article and Find Full Text PDFThe simultaneous acquisition of electroencephalographic (EEG) signals and functional magnetic resonance images (fMRI) aims to measure brain activity with good spatial and temporal resolution. This bimodal neuroimaging can bring complementary and very relevant information in many cases and in particular for epilepsy. Indeed, it has been shown that it can facilitate the localization of epileptic networks.
View Article and Find Full Text PDFResting-state Arterial Spin Labeling (rs-ASL) is a rather confidential method compared to resting-state BOLD. As ASL allows to quantify the cerebral blood flow, unlike BOLD, rs-ASL can lead to significant clinical subject-scaled applications. Despite directly impacting clinical practicability and functional networks estimation, there is no standard for rs-ASL regarding the acquisition duration.
View Article and Find Full Text PDFBackground: Renal failure is predictive of mortality in the early postliver-transplantation period and calcineurin inhibitors toxicity is a main challenge. Our aim is to assess the impact of longitudinal tacrolimus exposure (TLE) and other variables on chronic kidney disease (CKD)-free 1-year-survival.
Methods: Retrospective data of consecutive patients transplanted between 2011 and 2016 and treated with tacrolimus were collected.
Myelin loss in the brain is a common occurrence in traumatic brain injury (TBI) that results from impact-induced acceleration forces to the head. Fast and abrupt head motions, either resulting from violent blows and/or jolts, cause rapid stretching of the brain tissue, and the long axons within the white matter tracts are especially vulnerable to such mechanical strain. Recent studies have shown that mechanotransduction plays an important role in regulating oligodendrocyte progenitors cell differentiation into oligodendrocytes.
View Article and Find Full Text PDFMeasures of brain activity through functional magnetic resonance imaging (fMRI) or electroencephalography (EEG), two complementary modalities, are ground solutions in the context of neurofeedback (NF) mechanisms for brain rehabilitation protocols. While NF-EEG (in which real-time neurofeedback scores are computed from EEG signals) has been explored for a very long time, NF-fMRI (in which real-time neurofeedback scores are computed from fMRI signals) appeared more recently and provides more robust results and more specific brain training. Using fMRI and EEG simultaneously for bi-modal neurofeedback sessions (NF-EEG-fMRI, in which real-time neurofeedback scores are computed from fMRI and EEG) is very promising for the design of brain rehabilitation protocols.
View Article and Find Full Text PDFThe design of glycogen phosphorylase (GP) inhibitors targeting the catalytic site of the enzyme is a promising strategy for a better control of hyperglycaemia in the context of type 2 diabetes. Glucopyranosylidene-spiro-heterocycles have been demonstrated as potent GP inhibitors, and more specifically spiro-oxathiazoles. A new synthetic route has now been elaborated through 1,3-dipolar cycloaddition of an aryl nitrile oxide to a glucono-thionolactone affording in one step the spiro-oxathiazole moiety.
View Article and Find Full Text PDFArterial spin labeling is a magnetic resonance perfusion imaging technique that, while providing results comparable to methods currently considered as more standard concerning the quantification of the cerebral blood flow, is subject to limitations related to its low signal-to-noise ratio and low resolution. In this work, we investigate the relevance of using a non-local patch-based super-resolution method driven by a high resolution structural image to increase the level of details in arterial spin labeling images. This method is evaluated by comparison with other image dimension increasing techniques on a simulated dataset, on images of healthy subjects and on images of subjects scanned for brain tumors, who had a dynamic susceptibility contrast acquisition.
View Article and Find Full Text PDFInteractions between axons and Schwann cells are essential for the acquisition of Schwann cell radial and longitudinal polarity and myelin sheath assembly. In the internode, the largest of these longitudinal domains, axon-Schwann cell interactions are mediated by the Nectin-like (Necl) cell adhesion proteins, also known as SynCAMs or Cadms. In particular, Necl-1/Cadm3 expressed on the axon surface binds to Necl-4/Cadm4 expressed along the adaxonal membrane of myelinating Schwann cells.
View Article and Find Full Text PDFObjective: Polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), which is a piezoelectric, biocompatible polymer, holds promise as a scaffold in combination with Schwann cells (SCs) for spinal cord repair. Piezoelectric materials can generate electrical activity in response to mechanical deformation, which could potentially stimulate spinal cord axon regeneration. Our goal in this study was to investigate PVDF-TrFE scaffolds consisting of aligned fibers in supporting SC growth and SC-supported neurite extension and myelination in vitro.
View Article and Find Full Text PDFLentiviral transduction is a gene delivery method that provides numerous advantages over direct transfection and traditional retroviral or adenoviral delivery methods. It facilitates for the transduction of primary cells inherently difficult to transfect, delivers constructs of interest to nondividing as well as dividing cells, and permits the long-term expression of sizable DNA inserts (e.g.
View Article and Find Full Text PDFThe ability to understand in great details, at the molecular level, the process of myelination in the peripheral nervous system (PNS) is, in no minor part, due to the availability of an in vitro culture model of PNS myelination. This culture system is based on the ability to prepare large population of highly purified Schwann cells and dorsal root ganglia neurons that, once co-cultured, can be driven to form in vitro well-defined myelinated axon units. In this chapter, we present our detailed protocols to establish these cell cultures that are derived from modifications of procedures developed 35-40 years ago.
View Article and Find Full Text PDFGrowth factors have key roles in liver physiology and pathology, particularly by promoting cell proliferation and growth. Recently, it has been shown that in mouse hepatocytes, epidermal growth factor receptor (EGFR) plays a crucial role in the activation of the xenosensor constitutive androstane receptor (CAR) by the antiepileptic drug phenobarbital. Due to the species selectivity of CAR signaling, here we investigated epidermal growth factor (EGF) role in CAR signaling in primary human hepatocytes.
View Article and Find Full Text PDFTissue inhibitor of metalloproteinase-3 (TIMP-3) inhibits the activities of various metalloproteinases including matrix metalloproteinases and ADAM family proteins. In the peripheral nervous system, ADAM17, also known as TNF-α converting enzyme (TACE), cleaves the extracellular domain of Nrg1 type III, an axonal growth factor that is essential for Schwann cell myelination. The processing by ADAM17 attenuates Nrg1 signaling and inhibits Schwann cell myelination.
View Article and Find Full Text PDFNectin-like 4 (NECL4, CADM4) is a Schwann cell-specific cell adhesion molecule that promotes axo-glial interactions. and studies have shown that NECL4 is necessary for proper peripheral nerve myelination. However, the molecular mechanisms that are regulated by NECL4 and affect peripheral myelination currently remain unclear.
View Article and Find Full Text PDFIn conjunction with the ISBI 2015 conference, we organized a longitudinal lesion segmentation challenge providing training and test data to registered participants. The training data consisted of five subjects with a mean of 4.4 time-points, and test data of fourteen subjects with a mean of 4.
View Article and Find Full Text PDFAxo-glial interactions are critical for myelination and the domain organization of myelinated fibers. Cell adhesion molecules belonging to the Cadm family, and in particular Cadm3 (axonal) and its heterophilic binding partner Cadm4 (Schwann cell), mediate these interactions along the internode. Using targeted shRNA-mediated knockdown, we show that the removal of axonal Cadm3 promotes Schwann cell myelination in the in vitro DRG neuron/Schwann cell myelinating system.
View Article and Find Full Text PDFThe accumulation of lipid droplets (LD) is frequently observed in hepatitis C virus (HCV) infection and represents an important risk factor for the development of liver steatosis and cirrhosis. The mechanisms of LD biogenesis and growth remain open questions. Here, transcriptome analysis reveals a significant upregulation of septin 9 in HCV-induced cirrhosis compared with the normal liver.
View Article and Find Full Text PDFThe mechanisms that coordinate and balance a complex network of opposing regulators to control Schwann cell (SC) differentiation remain elusive. Here we demonstrate that zinc-finger E-box-binding homeobox 2 (Zeb2, also called Sip1) transcription factor is a critical intrinsic timer that controls the onset of SC differentiation by recruiting histone deacetylases HDAC 1 and 2 (HDAC1/2) and nucleosome remodeling and deacetylase complex (NuRD) co-repressor complexes in mice. Zeb2 deletion arrests SCs at an undifferentiated state during peripheral nerve development and inhibits remyelination after injury.
View Article and Find Full Text PDFIn this paper, we introduce a new locally multivariate procedure to quantitatively extract voxel-wise patterns of abnormal perfusion in individual patients. This a contrario approach uses a multivariate metric from the computer vision community that is suitable to detect abnormalities even in the presence of closeby hypo- and hyper-perfusions. This method takes into account local information without applying Gaussian smoothing to the data.
View Article and Find Full Text PDFGlycogen phosphorylase (GP) is a target for the treatment of hyperglycaemia in the context of type 2 diabetes. This enzyme is responsible for the depolymerization of glycogen into glucose thereby affecting the levels of glucose in the blood stream. Twelve new d-glucopyranosylidene-spiro-isoxazolines have been prepared from O-peracylated exo-D-glucals by regio- and stereoselective 1,3-dipolar cycloaddition of nitrile oxides generated in situ by treatment of the corresponding oximes with bleach.
View Article and Find Full Text PDFCytochrome P450 (CYP) expression and activity are not homogeneous in the liver lobules. Indeed, CYPs are mainly expressed and induced in centrilobular hepatocytes. The wingless-type MMTV integration site family (WNT)/β-catenin pathway was identified as a major regulator of this zonal organization.
View Article and Find Full Text PDFComput Med Imaging Graph
December 2015
This paper presents a sparse representation and an adaptive dictionary learning based method for automated classification of multiple sclerosis (MS) lesions in magnetic resonance (MR) images. Manual delineation of MS lesions is a time-consuming task, requiring neuroradiology experts to analyze huge volume of MR data. This, in addition to the high intra- and inter-observer variability necessitates the requirement of automated MS lesion classification methods.
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