Oxidative Stress Markers and Histopathological Changes in Selected Organs of Mice Infected with Murine Norovirus 1 (MNV-1).

This paper describes the effects of murine norovirus (MNV) infection on oxidative stress and histopathological changes in mice. This study uses histopathological assays, enzymatic and non-enzymatic antioxidant markers, and total oxidative status and capacity (TOS, TAC). The results suggest that MNV infection can lead to significant changes with respect to the above-mentioned parameters in various organs.

Glycogen phosphorylase inhibition improves cognitive function of aged mice.

Inhibition of glycogen breakdown blocks memory formation in young animals, but it stimulates the maintenance of the long-term potentiation, a cellular mechanism of memory formation, in hippocampal slices of old animals. Here, we report that a 2-week treatment with glycogen phosphorylase inhibitor BAY U6751 alleviated memory deficits and stimulated neuroplasticity in old mice. Using the 2-Novel Object Recognition and Novel Object Location tests, we discovered that the prolonged intraperitoneal administration of BAY U6751 improved memory formation in old mice.

Overexpression of Promoter Binding Protein-1 Enhances Proliferation and Glucose Metabolism of Melanoma Cells Lines.

Background/aim: c-MYC promoter binding protein (MBP-1) is a product of alternatively translated mRNA encoding alpha-enolase (ENO1). In contrast to ENO1, MBP-1 possesses no enzymatic activity but acts as a transcriptional repressor of c-MYC. Ectopic over-expression of MBP-1 in tumor cells was shown to reduce cell proliferation and tumorigenicity, thus making it an attractive target for anticancer strategies.

Progressive Ataxia, Memory Impairments, and Seizure Episodes in Mouse Variant Affecting Alpha II Spectrin's Scaffold Stability.

spectrinopathies refer to a group of rare, inherited diseases associated with damage to non-erythrocytic α-II spectrin (α-II). They are linked to a range of mild to severe neuropathologies of the central and peripheral nervous systems, such as early infantile epileptic encephalopathy type 5, cerebellar ataxia, inherited peripheral neuropathy, and spastic paraplegia. Modeling human encephalopathies in laboratory animals has been challenging partially because no haploinsufficiency-related phenotypes unfold in heterozygous deficient mice nor stable transgenic lines of mice mimicking missense human mutations have been created to date.

Alpha-Enolase (ENO1) Correlates with Invasiveness of Cutaneous Melanoma-An In Vitro and a Clinical Study.

Alpha-enolase (ENO1) is a glycolytic metalloenzyme, and its overexpression occurs in numerous cancers, contributing to cancer cell survival, proliferation, and maintenance of the Warburg effect. Patients with an overexpression of ENO1 have a poor prognosis. The aim of the present study was to investigate the prognostic significance of ENO1 in surgical resections from 112 melanoma patients and to assess its expression and enzymatic activity in normoxia and hypoxia in several melanoma cell lines.

Analysis of enterotoxigenic effect of Staphylococcus aureus and Staphylococcus epidermidis enterotoxins C and L on mice.

Pathogenic properties of orthologues to S. aureus staphylococcal enterotoxin C (SEC) and staphylococcal enterotoxin L (SEL) produced by S. epidermidis are largely unexplored.

An alpha II spectrin mutant peptide with unstable scaffold structure and increased sensitivity to calpain cleavage.

A spontaneous missense mutation in the alpha II spectrin (αII) gene, replacing a highly conserved arginine 1098 with the glutamine (R1098Q), causes progressive neurodegeneration in heterozygous mutant mice. The molecular mechanism underlying this phenotype is unknown but the accumulation of 150kD αII breakdown products in brains of homozygous mutant embryos suggests an imbalance in the substrate level control of αII cleavage by calpains. This is further supported by in silico simulation predicting unmasked calpain target site and increased spectrin scaffold bending and flexibility of R1098Q mutant peptide.

Missing the sweet spot: one of the two N-glycans on human Gb3/CD77 synthase is expendable.

N-glycosylation is a ubiquitous posttranslational modification that may influence folding, subcellular localization, secretion, solubility and oligomerization of proteins. In this study, we examined the effects of N-glycans on the activity of human Gb3/CD77 synthase, which catalyzes the synthesis of glycosphingolipids with terminal Galα1→4Gal (Gb3 and the P1 antigen) and Galα1→4GalNAc disaccharides (the NOR antigen). The human Gb3/CD77 synthase contains two occupied N-glycosylation sites at positions N121 and N203.

Age-dependent ataxia and neurodegeneration caused by an αII spectrin mutation with impaired regulation of its calpain sensitivity.

The neuronal membrane-associated periodic spectrin skeleton (MPS) contributes to neuronal development, remodeling, and organization. Post-translational modifications impinge on spectrin, the major component of the MPS, but their role remains poorly understood. One modification targeting spectrin is cleavage by calpains, a family of calcium-activated proteases.

A Novel, LAT/Lck Double Deficient T Cell Subline J.CaM1.7 for Combined Analysis of Early TCR Signaling.

Intracellular signaling through the T cell receptor (TCR) is essential for T cell development and function. Proper TCR signaling requires the sequential activities of Lck and ZAP-70 kinases, which result in the phosphorylation of tyrosine residues located in the CD3 ITAMs and the LAT adaptor, respectively. LAT, linker for the activation of T cells, is a transmembrane adaptor protein that acts as a scaffold coupling the early signals coming from the TCR with downstream signaling pathways leading to cellular responses.

Increased Protein Stability and Interleukin-2 Production of a LAT Variant With Possible Implications for T Cell Anergy.

The adaptor LAT plays a crucial role in the transduction of signals coming from the TCR/CD3 complex. Phosphorylation of some of its tyrosines generates recruitment sites for other cytosolic signaling molecules. Tyrosine 132 in human LAT is essential for PLC-γ activation and calcium influx generation.

An Antibody Specific for the Dog Leukocyte Antigen DR (DLA-DR) and Its Novel Methotrexate Conjugate Inhibit the Growth of Canine B Cell Lymphoma.

Canine B-cell lymphoma (CBL) is an incurable, spontaneous lymphoid malignancy constituting an accurate animal model for testing novel therapeutic strategies in human medicine. Resources of available species-specific therapeutic monoclonal antibodies (mAbs) targeting CBL are scarce. The aim of the present study was to evaluate the therapeutic potential of mAb B5, specific for the dog leukocyte antigen DR (DLA-DR) and its antibody-drug conjugate with methotrexate (B5-MTX).

Development of novel monoclonal antibodies to dog leukocyte antigen DR displaying direct and immune-mediated cytotoxicity toward canine lymphoma cell lines.

Spontaneous canine lymphoma (CL) has become a promising, nonrodent model for advancing the therapeutic strategies of human hematological malignancies. As new resources for veterinary and comparative studies on CL-associated antigens, we developed 2 novel mouse monoclonal antibodies, denoted B5 and E11, that recognized the canine major histocompatibility Class II DR antigens (dog leukocyte antigen DR). Using flow cytometry and solid phase immunoenzymatic assays, we showed that the antigens recognized by B5 and E11 were strongly expressed in several CL cell lines and the ex vivo canine neoplastic cells of B and mixed B/T immunophenotypes.

A Stretch of Negatively Charged Amino Acids of Linker for Activation of T-Cell Adaptor Has a Dual Role in T-Cell Antigen Receptor Intracellular Signaling.

The adaptor protein linker for activation of T cells (LAT) has an essential role transducing activatory intracellular signals coming from the TCR/CD3 complex. Previous reports have shown that upon T-cell activation, LAT interacts with the tyrosine kinase Lck, leading to the inhibition of its kinase activity. LAT-Lck interaction seemed to depend on a stretch of negatively charged amino acids in LAT.

Anti-GITR Antibody Treatment Increases TCR Repertoire Diversity of Regulatory but not Effector T Cells Engaged in the Immune Response Against B16 Melanoma.

Crosslinking of glucocorticoid-induced TNF family-related receptor (GITR) with agonist antibodies restores cancer immunity by enhancing effector T cell (Teff) responses while interfering with intra-tumor regulatory T cell (Treg) stability and/or accumulation. However, how anti-GITR antibody infusion changes T cell receptor (TCR) repertoire of Teffs and Tregs engaged in anti-tumor immune response is unclear. Here, we used a transgenic mouse model (TCRmini) where T cells express naturally generated but limited TCR repertoire to trace the fate of individual T cells recognizing B16 melanoma in tumor-bearing mice, treated or non-treated with an anti-GITR monoclonal antibody DTA-1.

Non-T cell activation linker (NTAL) proteolytic cleavage as a terminator of activatory intracellular signals.

Non-T cell activation linker is an adaptor protein that is tyrosine phosphorylated upon cross-linking of immune receptors expressed on B lymphocytes, NK cells, macrophages, basophils, or mast cells, allowing the recruitment of cytosolic mediators for downstream signaling pathways. Fas receptor acts mainly as a death receptor, and when cross-linked with Fas ligand, many proteins are proteolytically cleaved, including several signaling molecules in T and B cells. Fas receptor triggering also interferes with TCR intracellular signals, probably by means of proteolytic cleavage of several adaptor proteins.

Search for the Function of NWC, Third Gene Within RAG Locus: Generation and Characterization of NWC-Deficient Mice.

NWC is a third gene within recombination activating gene (RAG) locus, which unlike RAG genes is ubiquitously expressed and encodes a unique protein containing three strongly evolutionarily conserved domains not found in any other known protein. To get insight into its function we identified several proteins co-immunoprecipitating with NWC protein and generated new NWC-deficient mice. Here, we present evidence that unlike many other ubiquitously expressed evolutionarily conserved proteins, functional inactivation of NWC does not cause any gross developmental, physiological or reproductive abnormalities and that under physiological conditions NWC may be involved in assembling and functioning of cilia, cell surface organelles found on nearly every eukaryotic cell.

Assessment of caspase mediated degradation of linker for activation of T cells (LAT) at a single cell level.

Caspase/Granzyme B mediated protein degradation is involved in elimination of activated T cell receptor (TCR) signaling molecules during processes of thymocyte selection and maintenance of peripheral homeostasis of T cells. Key components of TCR signaling cassette including LAT undergo biological inactivation in response to pro-apoptotic or anergy inducing environmental stimuli. Although available Western immunoblotting-based techniques are appropriate for detection of protein degradation in bulk populations of target cells, quantitative assessment of this process at a single cell level requires a different approach.

The membrane adaptor LAT is proteolytically cleaved following Fas engagement in a tyrosine phosphorylation-dependent fashion.

Engagement of the TCR (T-cell receptor) induces tyrosine phosphorylation of the LAT (linker for the activation of T-cells) adaptor, and thereby it recruits several cytosolic mediators for downstream signalling pathways. The Fas protein is essential for T-lymphocyte apoptosis, and following Fas engagement, many proteins are proteolytically cleaved, including several molecules that are important for the transduction of TCR intracellular signals. In the present study, we demonstrate that the adaptor LAT is also subject to a proteolytic cleavage in mature T-lymphocytes and thymocytes in response to Fas engagement, and also on TCR stimulation, and we identify three aspartic acid residues at which LAT is cleaved.

Effects of tamoxifen on estrogen receptor-α level in immune cells and humoral specific response after immunization of C3H/He male mice with syngeneic testicular germ cells (TGC).

Estrogens and estrogen receptors (ERs) are potent regulators of the immune response. Disruption of ERα or modulation of its function by selective ligands during experimental autoimmune conditions changes the course of disease by influencing specific humoral and cellular responses. However, it is not known whether fluctuation in the ERα level and the variable accessibility to its ligands in immune cells influence the development of specific immune responses against auto-antigens.

Complexity of transcriptional regulation within the Rag locus: identification of a second Nwc promoter region within the Rag2 intron.

Nwc represents a mysterious third evolutionarily conserved gene within the Rag locus. Here, we analyzed the phenotype of Nwc(tmpro1) mice, in which the Rag2 intragenic region containing the previously identified promoter responsible for initiating transcription of Nwc in all cells except lymphocytes was deleted by homologous recombination. Despite strong nonlymphocyte-specific inhibition of Nwc transcription which runs through the regulatory region of Rag genes, their expression remained suppressed, and no developmental, morphological, anatomical, functional, physiological, or cellular defects in Nwc(tmpro1) mice could be observed.

Peripheral Thy1+ lymphocytes rearranging TCR-gammadelta genes in LAT-deficient mice.

Linker for activation of T cells (LAT) is an adaptor molecule indispensable for development of alphabeta and gammadelta T lymphocytes. Surprisingly, using a new model of LAT-deficient mice we found that despite arrested thymic development, a discrete population of cells with active Lat promoter, expressing Thy1 molecules, accumulated in peripheral lymphoid organs of homozygous (Lat(Inv/Inv)) mutant mice. By measuring frequencies of TCR gene rearrangements in conjunction with a panel of cell surface Ag, we dissected two subsets of these Thy1(+) cells.

Loss of the LAT adaptor converts antigen-responsive T cells into pathogenic effectors that function independently of the T cell receptor.

Despite compromised T cell antigen receptor (TCR) signaling, mice in which tyrosine 136 of the adaptor linker for activation of T cells (LAT) was constitutively mutated (Lat(Y136F) mice) accumulate CD4(+) T cells that trigger autoimmunity and inflammation. Here we show that equipping postthymic CD4(+) T cells with LATY136F molecules or rendering them deficient in LAT molecules triggers a lymphoproliferative disorder dependent on prior TCR engagement. Therefore, such disorders required neither faulty thymic T cell maturation nor LATY136F molecules.