Project description:The purpose of this experiment is to respond to the NIGMS mandate to screen Core F generated glycosyltransferase KO mice in Core E and Core C. The goal is to screen several tissues for gene expression changes in ST6GalNAc2 KO mice and B4GalNT1/B4GalNT2 double KO mice relative to C75 Wild Type controls. Tissues for Core E analysis were selected by mining public databases including the NIH GEO database for tissues that expressed the KO genes at moderate to high levels.
Project description:The purpose of this experiment is to respond to the NIGMS mandate to screen Core F generated glycosyltransferase KO mice in Core E and Core C. The goal is to screen several tissues for gene expression changes in ST6GalNAc2 KO mice and B4GalNT1/B4GalNT2 double KO mice relative to C75 Wild Type controls. Tissues for Core E analysis were selected by mining public databases including the NIH GEO database for tissues that expressed the KO genes at moderate to high levels. Results from Core E gene expression analysis are then used to help Core C select tissues to follow up with glycan analysis on in each of the KO mice. For the ST6GalNAc2 KO mouse we selected: Brain, Small Intestine, Lymph Node and Thyroid for analysis. For the B4GalNT1/B4GalNT2 double KO mouse we selected: Kidney, Mammary Gland, Thymus and Testes for analysis. Wild type tissues were analyzed in parellel.
Project description:Peroxisomes are versatile single membrane-enclosed cytoplasmic organelles, involved in reactive oxygen species (ROS) and lipid metabolism and diverse other metabolic processes. Peroxisomal disorders result from mutations in Pex genes-encoded proteins named peroxins (PEX proteins) and single peroxisomal enzyme deficiencies. The PEX11 protein family (α, β, and γ isoforms) plays an important role in peroxisomal proliferation and fission. However, their specific functions and the metabolic impact caused by their deficiencies have not been precisely characterized. To understand the systemic molecular alterations caused by peroxisomal defects, here we utilized untreated peroxisomal biogenesis factor 11α knockout (Pex11α KO) mouse model and performed serial relative-quantitative lipidomic, metabolomic, and proteomic analyses of serum, liver, and heart tissue homogenates. We demonstrated significant specific changes in the abundances of multiple lipid species, polar metabolites, and proteins and dysregulated metabolic pathways in distinct biological specimens of the Pex11α KO adult mice in comparison to the wild type (WT) controls. Overall, the present study reports comprehensive semi-quantitative molecular omics information of the Pex11α KO mice, which might serve in the future as a reference for a better understanding of the roles of Pex11α and underlying pathophysiological mechanisms of peroxisomal biogenesis disorders.
Project description:The Sda histo-blood group antigen [GalNAcβ1-4(NeuAcα2-3)Galβ-R] is present in colon, kidney and body fluids among 96-98% of Europeans whilst 90% have Sda-positive erythrocytes. Sda is implicated in various infections and constitutes a potential biomarker for colon cancer. The 2-4% truly Sd(a‒) individuals may produce anti-Sda, which can lead to incompatible blood transfusions, especially if donors with the high-expressing Sda phenotype, Sd(a++) or Cad, are involved. It was hypothesized that defects in the B4GALNT2-encoded β4GalNAc-T2 glycosyltransferase underlies the null phenotype. We recently reported the association of B4GALNT2 mutations with the Sd(a‒) phenotype, which formally established the SID blood-group system. In the present study, we provide causal proof and glycoprotein profiling underpinning this correlation. Phenotypically Sd(a‒) HEK293 cells were transfected with different B4GALNT2 constructs and evaluated by immunostaining and LC-MS/MS-based glycoproteomics. The pre¬dominant SIDnull allele with SNP rs7224888:T>C (p.Cys406Arg) abolished Sda synthesis, while this antigen was detectable as N- or O-glycans on multiple glycoproteins following transfection of wildtype B4GALNT2. Surprisingly, two rare missense SNPs, rs148441237:A>G and rs61743617:C>T, found in a Sd(a‒) compound heterozygote gave results similar to wildtype. To elucidate if Sd(a++)/Cad is also due to B4GALNT2 alterations, its coding region and 2 kbp upstream were sequenced in five Cad individuals. No genetic changes were associated with this phenotype but a detailed erythroid Cad glycoprotein profile was obtained, especially for GLPA (O-glycosylation) and, for the first time, B3AT (N-glycosylation). In conclusion, the p.Cys406Arg β4GalNAc-T2 variant causes Sda-deficiency in humans, while the enigmatic Cad phenotype remains unresolved, albeit further characterized.
Project description:To investigate the molecular mechanisms by which KIBRA regulates exosome secretion, we performed mass spectral (MS) analysis and an isobaric tag for relative and absolute quantitation (iTRAQ) assay to screen the differentially-expressed proteins in the brains of KIBRA-KO mice compared with their WT littermates.
Project description:Male and female knockout (KO) mice and age- and sex-matched C57BL/6J wild-type (WT) were compared. The KO mice had been backcrossed for more than 10 generations onto C57BL6/J background. The present study includes 4 strains of mice (WT, CCK1 receptor KO, CCK2 receptor KO, and CCK1+CCK2 receptor double KO). Animals that were subjected to gene expression profiling received no treatment and were killed under deep anesthesia.
Project description:The beta-secretase BACE1 is a central drug target for Alzheimer’s disease. Clinically tested, BACE1-directed inhibitors also block the homologous protease BACE2. Yet, little is known about physiological BACE2 substrates and functions in vivo. Here, we performed glycoprotein enrichment and subsequent discovery proteomics to identify substrates of the protease BACE2 in plasma of mice. Therefore, we analysed plasma from BACE2 KO, BACE1/2 double KO and WT controls, as well as BACE1 KO with a separate WT control. Inactivation of BACE2, but not BACE1, inhibited shedding of VEGFR3/FLT4. Thus, sVEGFR3 represents a pharmacodynamic plasma marker for BACE2 activity in vivo.