Project description:Genome-wide DNA methylation reference profiles of CD4+ cells after CD3 and CD28 stimulation in two healthy human individuals using the MeDIP technique a custom oligonucleotide array targetting the vast majority of annotated TSSs and non-promoter CGIs in the human genome.
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.
Project description:The loss of the CD28 co-stimulatory molecule by CD4+ lymphocytes (CD28null T cells) is accompanied by the acquisition of new biological and functional properties that lead to an impaired immune response. The regulatory mechanisms that govern the appearance and function of this cell subset in several inflammatory disorders and in healthy individuals, mainly in aging, are yet a controversial point. Here, we provide the whole-genome DNA methylation and gene expression profiles of CD28null T cells and its CD28+ counterpart. A comparative analysis reveals that 296 genes are differentially methylated between both cell subsets. One hundred sixty (160 genes) associated with the cytotoxicy ability (e.g., GRZB, TYROBP, and RUNX3) and cytokine/chemokine signaling (e.g., CX3CR1, CD27, and IL1R) are demetylated in CD28null T cells, whilst 136 de-novo methylated genes matched with defects in the TCR signaling pathway (e.g., ITK, TXK, CD3G, and LCK). Moreover, we show that genes related inflammasome activation are differentially expressed between CD28null and CD28+ T cells, highlight the contribution of this pathways to the pro-inflammatory profile of CD28null T cells. Overall, our results reveal that CD28null T cells have a unique DNA methylation landscape, which is associated with alteration in gene expression and contributes to the functionality of these cells. Understanding these epigenetic regulatory mechanisms could provide novel therapeutic strategies to prevent the accumulation and activation of these cells in aging and inflammatory disorders.
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs. Two-condition experiment, KP MSCs vs. 3A6 MSCs.
Project description:The loss of the CD28 co-stimulatory molecule by CD4+ lymphocytes (CD28null T cells) is accompanied by the acquisition of new biological and functional properties that lead to an impaired immune response. The regulatory mechanisms that govern the appearance and function of this cell subset in several inflammatory disorders and in healthy individuals, mainly in aging, are yet a controversial point. Here, we provide the whole-genome DNA methylation profile of CD28null T cells and its CD28+ counterpart. A comparative analysis reveals that 296 genes are differentially methylated between both cell subsets. One hundred sixty (160 genes) associated with the cytotoxicy ability (e.g., GRZB, TYROBP, and RUNX3) and cytokine/chemokine signaling (e.g., CX3CR1, CD27, and IL1R) are demetylated in CD28null T cells, whilst 136 de-novo methylated genes matched with defects in the TCR signaling pathway (e.g., ITK, TXK, CD3G, and LCK). Overall, our results reveal that CD28null T cells have a unique DNA methylation landscape, which is associated with alteration in gene expression and contributes to the functionality of these cells. Understanding these epigenetic regulatory mechanisms could provide novel therapeutic strategies to prevent the accumulation and activation of these cells in aging and inflammatory disorders.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.