Targeted Metabolic Profiling of the Tg197 Mouse Model Reveals Itaconic Acid as a Marker of Rheumatoid Arthritis

Rheumatoid arthritis is a progressive, highly debilitating disease where early diagnosis, enabling rapid clinical intervention, would provide obvious benefits to patients, healthcare systems, and society. Novel biomarkers that enable noninvasive early diagnosis of the onset and progression of the disease provide one route to achieving this goal. Here a metabolic profiling method has been applied to investigate disease development in the Tg197 arthritis mouse model. Hind limb extract profiling demonstrated clear differences in metabolic phenotypes between control (wild type) and Tg197 transgenic mice and highlighted raised concentrations of itaconic acid as a potential marker of the disease. These changes in itaconic acid concentrations were moderated or indeed reversed when the Tg197 mice were treated with the anti-hTNF biologic infliximab (10 mg/kg twice weekly for 6 weeks). Further in vitro studies on synovial fibroblasts obtained from healthy wild-type, arthritic Tg197, and infliximab-treated Tg197 transgenic mice confirmed the association of itaconic acid with rheumatoid arthritis and disease-moderating drug effects. Preliminary indications of the potential value of itaconic acid as a translational biomarker were obtained when studies on K4IM human fibroblasts treated with hTNF showed an increase in the concentrations of this metabolite. © 2016 American Chemical Society

Analysis of Up-Regulation of DNA-PKcs and Its Mechanism in Human Gliomas

OBJECTIVE To detect the differences in gene expression of nonhomologous end-joining pathway including Ku70, Ku80, ERCC4, lig4 and DNA-PKcs between human primary gliomas and normal brain tissues, and furthermore, to explore the underlying mechanism for the expression alteration. METHODS The expression levels of Ku70, Ku80, ERCC4, lig4 and DNA-PKcs in 36 specimens of glioma and 12 specimens of normal brain tissue were measured using SYBR green-based real-time quantitative PCR. Methylation of DNA-PKcs was detected through methylation-specifi c PCR (MSP). RESULTS There was no significant difference in expression of Ku70, Ku80, ERCC4 and lig4 between human primary gliomas and normal brain tissues (P < 0.05), while DNA-PKcs were significantly up-regulated (P = 0.002). The expression of DNA-PKcs was significantly higher in patients with grade III and IV diseases compared to patients with grade II disease or in normal brain tissues (P < 0.05). Moreover, glioma tissue showed weaker methylation than normal brain tissue. CONCLUSION The up-regulation of the DNA-PKcs may be associated with pathogenesis of glioma. Demethylation of DNA-PKcs promoter is an important reason for its up-regulation

Geometric representation of association between categories

Categorical data, simplex, triangular plot, paired comparisons, rank orders, permutation polytope, center of gravity, BTL model, Rasch model, inertia, association model, variation, multidimensional unfolding, biplot, multinomial response model, loglinear model, forced classification, classification tree,

In Vitro and In Vivo Interactions of DNA Ligase IV with a Subunit of the Condensin Complex

Several findings have revealed a likely role for DNA ligase IV, and interacting protein XRCC4, in the final steps of mammalian DNA double-strand break repair. Recent evidence suggests that the human DNA ligase IV protein plays a critical role in the maintenance of genomic stability. To identify protein–protein interactions that may shed further light on the molecular mechanisms of DSB repair and the biological roles of human DNA ligase IV, we have used the yeast two-hybrid system in conjunction with traditional biochemical methods. These efforts have resulted in the identification of a physical association between the DNA ligase IV polypeptide and the human condensin subunit known as hCAP-E. The hCAP-E polypeptide, a member of the Structural Maintenance of Chromosomes (SMC) super-family of proteins, coimmunoprecipitates from cell extracts with DNA ligase IV. Immunofluorescence studies reveal colocalization of DNA ligase IV and hCAP-E in the interphase nucleus, whereas mitotic cells display colocalization of both polypeptides on mitotic chromosomes. Strikingly, the XRCC4 protein is excluded from the area of mitotic chromosomes, suggesting the formation of specialized DNA ligase IV complexes subject to cell cycle regulation. We discuss our findings in light of known and hypothesized roles for ligase IV and the condensin complex