Bacterial immunogenic α-galactosylceramide identified in the murine large intestine: dependency on diet and inflammation

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Murine Sialidase Neu3 facilitates GM2 degradation and bypass in mouse model of Tay-Sachs disease

Erdemli, Esra/0000-0002-9737-269X; von Gerichten, Johanna/0000-0002-9224-5296; Hopf, Carsten/0000-0003-0802-6451; Dalkara, Turgay/0000-0003-3943-7819WOS: 000419261500003PubMed: 28974375Tay-Sachs disease is a severe lysosomal storage disorder caused by mutations in Hexa, the gene that encodes for the a subunit of lysosomal p-hexosaminidase A (HEXA), which converts GM2 to GM3 ganglioside. Unexpectedly, Hexa(-/-) mice have a normal lifespan and show no obvious neurological impairment until at least one year of age. These mice catabolize stored GM2 ganglioside using sialidase(s) to remove sialic acid and form the glycolipid GA2, which is further processed by D-hexosaminidase B. Therefore, the presence of the sialidase (s) allows the consequences of the Hexa defect to be bypassed. To determine if the sialidase NEU3 contributes to GM2 ganglioside degradation, we generated a mouse model with combined deficiencies of HEXA and NEU3. The Hexa(-/-) Neu3(-/-) mice were healthy at birth, but died at 1.5 to 4.5 months of age. Thin-layer chromatography and mass spectrometric analysis of the brains of Hexa(-/-) Neu3(-/-) mice revealed the abnormal accumulation of GM2 ganglioside. Histological and immunohistochemical analysis demonstrated cytoplasmic vacuolation in the neurons. Electron microscopic examination of the brain, kidneys and testes revealed pleomorphic inclusions of many small vesicles and complex lamellar structures. The Hexa(-/-)Neu3(-/-) mice exhibited progressive neurodegeneration with neuronal loss, Purkinje cell depletion, and astrogliosis. Slow movement, ataxia, and tremors were the prominent neurological abnormalities observed in these mice. Furthermore, radiographs revealed abnormalities in the skeletal bones of the Hexa(-/-)Neu3(-/-) mice. Thus, the Hexa(-/-) Neu3(-/-) mice mimic the neuropathological and clinical abnormalities of the classical early-onset Tay-Sachs patients, and provide a suitable model for the future pre-clinical testing of potential treatments for this condition

Device-Controlled Microcondensation for Spatially Confined On-Tissue Digests in MALDI Imaging of <i>N</i>-Glycans

On-tissue enzymatic digestion is a prerequisite for MALDI mass spectrometry imaging (MSI) and spatialomic analysis of tissue proteins and their N-glycan conjugates. Despite the more widely accepted importance of N-glycans as diagnostic and prognostic biomarkers of many diseases and their potential as pharmacodynamic markers, the crucial sample preparation step, namely on-tissue digestion with enzymes like PNGaseF, is currently mainly carried out by specialized laboratories using home-built incubation arrangements, e.g., petri dishes placed in an incubator. Standardized spatially confined enzyme digests, however, require precise control and possible regulation of humidity and temperature, as high humidity increases the risk of analyte dislocation and low humidity compromises enzyme function. Here, a digestion device that controls humidity by cyclic ventilation and heating of the slide holder and the chamber lid was designed to enable controlled micro-condensation on the slide and to stabilize and monitor the digestion process. The device presented here may help with standardization in MSI. Using sagittal mouse brain sections and xenografted human U87 glioblastoma cells in CD1 nu/nu mouse brain, a device-controlled workflow for MALDI MSI of N-glycans was developed

Integrating Real-Time Control Applications into Different Control Systems

Porting complex device servers from one control system to another is often amajor effort due to the strong code coupling of the business logic to control system data structures.Together with its partners from the Helmholtz Association and from industry,DESY is developing a control system adapter as part of the MTCA4U tool kit.It allows to writeapplications in a control system independent way, while still being able toupdate the process variables and react on control system triggers.Special attention has been paid to make the implementation thread safe andreal time capable, while still providing the required abstraction and avoidingperformance losses.We report on the status of the project and the plans to implement new features

Male meiotic cytokinesis requires ceramide synthase 3-dependent sphingolipids with unique membrane anchors

Somatic cell cytokinesis was shown to involve the insertion of sphingolipids (SLs) to midbodies prior to abscission. Spermatogenic midbodies transform into stable intercellular bridges (ICBs) connecting clonal daughter cells in a syncytium. This process requires specialized SL structures. (1) Using high resolution-mass spectrometric imaging, we show in situ a biphasic pattern of SL synthesis with testis-specific anchors. This pattern correlates with and depends on ceramide synthase 3 (CerS3) localization in both, pachytene spermatocytes until completion of meiosis and elongating spermatids. (2) Blocking the pathways to germ cell-specific ceramides (CerS3-KO) and further to glycosphingolipids (glucosylceramide synthase-KO) in mice highlights the need for special SLs for spermatid ICB stability. In contrast to somatic mitosis these SLs require ultra-long polyunsaturated anchors with unique physico-chemical properties, which can only be provided by CerS3. Loss of these anchors causes enhanced apoptosis during meiosis, formation of multinuclear giant cells and spermatogenic arrest. Hence, testis-specific SLs, which we also link to CerS3 in human testis, are quintessential for male fertility

Glioblastoma multiforme: Metabolic differences to peritumoral tissue and IDH-mutated gliomas revealed by mass spectrometry imaging.

Kampa JM, Kellner U, Marsching C, et al. Glioblastoma multiforme: Metabolic differences to peritumoral tissue and IDH-mutated gliomas revealed by mass spectrometry imaging. Neuropathology : official journal of the Japanese Society of Neuropathology. 2020;40(6):546-558.Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor. High infiltration rates and poor therapy responses make it the deadliest glioma. The tumor metabolism is known to differ from normal one and is influenced through various factors which can lead to longer survival. Metabolites are small molecules (<1500Da) that display the metabolic pathways in the tissue. To determine the metabolic alterations between tumor and peritumoral tissue in human GBMs, mass spectrometry imaging (MSI) was performed on thin sections from 25 resected tumors. In addition, the GBMs were compared with six gliomas harboring a mutation in the isocitrate dehydrogenase (IDH1) gene (IDH1). With this technique, a manifold of analytes can be easily visualized on a single tissue section. Metabolites were annotated based on their accurate mass using high resolution MSI. Differences in their mean intensities in the tumor and peritumoral areas were statistically evaluated and abundances were visualized on the tissue. Enhanced levels of the antioxidants ascorbic acid, taurine, and glutathione in tumor areas suggest protective effects on the tumor. Increased levels of purine and pyrimidine metabolism compounds in GBM areas indicate the high energy demand. In accordance with these results, enhanced abundances of lactate and glutamine were detected. Moreover, decreased abundance of N-acetylaspartate, a marker for neuronal health, was measured in tumor areas. Obtained metabolic information could potentially support and personalize therapeutic approaches, hence emphasizing the suitability of MSI for GBM research. © 2020 The Authors. Neuropathology published by John Wiley & Sons Australia, Ltd on behalf of Japanese Society of Neuropathology

Drivers and Software for MicroTCA.4

The MicroTCA.4 crate standard provides a powerful electronic platform for digital and analogue signal processing.Besides excellent hardware modularity, it is the software reliability and flexibility as well as the easy integration into existing Software infrastructures that will drive the widespread adoption of the new standard. The DESY MicroTCA.4 User Tool Kit (MTCA4U) comprises three main components: A Linux device driver, a C++ API for accessing the MicroTCA. 4 devices and a control system interface layer. Themain focus of the tool kit is flexibility to enable fast development. The universal, expandable PCIexpress driver and a register mapping library allow out of the box Operation of all MicroTCA.4 devices which carry firmware developed with the DESY FPGA board support package. The controlsystem adapter provides callback functions to decouple the application code from the middleware layer. Like this the same business logic can be used at different facilities without further modification

Renal globotriaosylceramide facilitates tubular albumin absorption and its inhibition protects against acute kidney injury

To elucidate the physiologic function of renal globotriaosylceramide (Gb3/CD77), which up-to-date has been associated exclusively with Shiga toxin binding, we have analyzed renal function in Gb3-deficient mice. Gb3 synthase KO (Gb3S(-/-)) mice displayed an increased renal albumin and low molecular weight protein excretion compared to WT. Gb3 localized at the brush border and within vesicular structures in WT proximal tubules and has now been shown to be closely associated with the receptor complex megalin/cubilin and with albumin uptake. In two clinically relevant mouse models of acute kidney injury caused by myoglobin as seen in rhabdomyolysis and the aminoglycoside gentamicin, Gb3S(-/-) mice showed a preserved renal function and morphology, compared to WT. Pharmacologic inhibition of glucosylceramide-based glycosphingolipids, including Gb3, in WT mice corroborated the results of genetically Gb3-deficient mice. In conclusion, our data significantly advance the current knowledge on the physiologic and pathophysiologic role of Gb3 in proximal tubules, showing an involvement in the reabsorption of filtered albumin, myoglobin and the aminoglycoside gentamicin