Mass Spectrometrical Analysis of Galectin Proteins in Primary Rat Cerebellar Astrocytes

Galectin-3 in T cell-mediated immunopathology and autoimmunity

Galectin-3 (Gal-3) is the only member of galectin family able to form pentamers and heterodimers with chemokines. Its presence in various cells and tissues suggests variety of regulatory functions in physiological conditions, but increasing body of evidence indicates involvement of Gal-3 in pathological cascades of many diseases. Gal-3 exerts different, sometimes opposite, effects in various disorders or in different phases of the same disease. These differences in action of Gal-3 are related to the localization of Gal-3 in the cell, types of receptors through which it acts, or the types of cells that secrete it. As a regulator of immune response and T-cell activity, Gal-3 appears to have important role in development of autoimmunity mediated by T cells. Absence of Gal-3 in C57Bl6 mice favors Th2 mediated inflammatory myocarditis but attenuate fibrosis. Recent data also indicate Gal-3 involvement in development atherosclerosis. In pathogenesis of diabetes type 1 and autoimmune components of diabetes type 2 Gal-3 may have detrimental or protective role depending on its intracellular or extracellular localization. Gal-3 mediates autoimmune hepatic damage through activation of T-cells or natural killer T cells. Gal-3 is an important mediator in neurodevelopment, neuropathology and behavior due to its expression both in neurons and glial cells. All together, assessing the role of Gal-3 in immunopathology and autoimmunity it could be concluded that it is an important participant in pathogenesis, as well as promising monitoring marker and therapeutic target.

Efficient induction of differentiation and growth inhibition in IDH1 mutant glioma cells by the DNMT Inhibitor Decitabine

Mutation in the IDH1 or IDH2 genes occurs frequently in gliomas and other human malignancies. In intermediate grade gliomas, IDH1 mutation is found in over 70% of tumors. These mutations impart the mutant IDH enzyme with a neomorphic activity - the ability to synthesize 2-hydroxyglutarate (2-HG). This ability leads to a reprogramming of chromatin state, a block in differentiation, and the establishment of the glioma hypermethylator phenotype (G-CIMP). It has been hypothesized but not proven that the extensive DNA methylation that occurs in G-CIMP tumors helps maintain and "lock in" glioma cancer cells in a dedifferentiated state. Here, we tested this hypothesis by treating patient derived IDH1 mutant glioma initiating cells (GIC) with non-cytotoxic, epigenetically targeted doses of the DNMT inhibitor decitabine. Global methylome analysis of treated IDH1 mutant GICs showed that DAC treatment resulted in reversal of DNA methylation marks induced by IDH and the re-expression of genes associated with differentiation. Accordingly, treatment of IDH1 mutant glioma cells resulted in a dramatic loss of stem-like properties and efficient adoption of markers of differentiation, effects not seen in decitabine treated IDH wild-type GICs. Induction of differentiation was much more efficient than that seen following treatment with a specific inhibitor of mutant IDH enzyme (Agios). Decitabine also decreased replicative potential and tumor growth in vivo. Reexpression of polycomb regulated genes accompanied these DAC-induced phenotypes. In total, our data indicates that targeting the pathologic DNA methylation in IDH mutant cells can reverse mutant IDH induced hypermethylation and block in differentiation and promote tumor control. These findings have substantial impact for exploring new treatment strategies for patients with IDH mutant gliomas.

Proteome reference map of the skin mucus of Atlantic cod (Gadus morhua) revealing immune competent molecules

The skin mucosal proteome of Atlantic cod (Gadus morhua) was mapped using a 2D PAGE, LC-MS/MS coupled approach. Mucosal proteins from naive fish were identified primarily by similarity searches across various cod EST databases. The identified proteins were clustered into 8 groups based on gene ontology classification for biological process. Most of the proteins identified from the gel are hitherto unreported for cod. Galectin-1, mannan binding lectin (MBL), serpins, cystatin B, cyclophilin A, FK-506 binding protein, proteasome subunits (alpha-3 and -7), ubiquitin, and g-type lysozyme are considered immune competent molecules. Five of the aforementioned proteins were cloned and their tissue distribution was analysed by RT-PCR.

Role of galectin-3 in prion infections of the CNS

Galectin-3 is a multi-functional protein and participates in mediating inflammatory reactions. The pronounced overexpression of galectin-3 in prion-infected brain tissue prompted us to study the role of this protein in a murine prion model. Immunofluorescence double-labelling identified microglia as the major cell type expressing galectin-3. Ablation of galectin-3 did not affect PrP(Sc)-deposition and development of gliosis. However, galectin-3(-/-)-mice showed prolonged survival times upon intracerebral and peripheral scrapie infections. Moreover, protein levels of the lysosomal activation marker LAMP-2 were markedly reduced in prion-infected galectin-3(-/-)-mice suggesting a role of galectin-3 in regulation of lysosomal functions. Lower mRNA levels of Beclin-1 and Atg5 in prion-infected wild-type and galectin-3(-/-)-mice indicated an impairment of autophagy although autophagosome formation was unchanged. The results point towards a detrimental role of galectin-3 in prion infections of the CNS and suggest that endo-/lysosomal dysfunction in combination with reduced autophagy may contribute to disease development.