Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Forkhead Box O (FoxO) transcription factors are conserved proteins involved in the regulation of life span and age-related diseases, such as diabetes and cancer. Stress stimuli or growth factor deprivation promote nuclear localization and activation of FoxO proteins, which - depending on the cellular context - leads to cell cycle arrest or apoptosis. Moreover, FoxOs can control oxidative stress resistance and cell metabolism. In endothelial cells (ECs), they additionally regulate angiogenesis and may promote inflammation and vessel destabilization implicating a role of FoxOs in vascular diseases. In several cancers, FoxO transcription factors exert a tumor-suppressive function, due to their critical role in regulating proliferation and survival. Others and we have previously shown that FoxOs can regulate these processes via two different mechanisms: either by direct binding to FoxO-responsive elements (FRE) at the promoter of target genes or by a poorly understood alternative process that does not require direct DNA binding and regulates key targets in primary human ECs. Here we performed an interaction study in ECs to identify new nuclear FoxO3 interaction partners, which might contribute to FoxO-dependent gene regulation. Mass spectrometry analysis of FoxO3-interacting proteins revealed Transformation/Transcription Domain-Associated Protein (TRRAP), a member of multiple histone acetyltransferase (HAT) complexes, as novel binding partner of FoxO family proteins. TRRAP is required to support FoxO3 transactivation and FoxO3-dependent apoptosis in ECs via transcriptional activation of the proapoptotic Bcl-2 family member BIM. Moreover, FoxO-TRRAP interaction might explain FoxO-induced alternative gene regulation via TRRAP-dependent recruitment to target promoters lacking FRE sequences.
Project description:Analysis of ex vivo isolated lymphatic endothelial cells from the dermis of patients to define type 2 diabetes-induced changes. Results preveal aberrant dermal lymphangiogenesis and provide insight into its role in the pathogenesis of persistent skin inflammation in type 2 diabetes. The ex vivo dLEC transcriptome reveals a dramatic influence of the T2D environment on multiple molecular and cellular processes, mirroring the phenotypic changes seen in T2D affected skin. The positively and negatively correlated dLEC transcripts directly cohere to prolonged inflammatory periods and reduced infectious resistance of patients´ skin. Further, lymphatic vessels might be involved in tissue remodeling processes during T2D induced skin alterations associated with impaired wound healing and altered dermal architecture. Hence, dermal lymphatic vessels might be directly associated with T2D disease promotion. Global gene expression profile of normal dermal lymphatic endothelial cells (ndLECs) compared to dermal lymphatic endothelial cells derived from type 2 diabetic patients (dLECs).Quadruplicate biological samples were analyzed from human lymphatic endothelial cells (4 x diabetic; 4 x non-diabetic). subsets: 1 disease state set (dLECs), 1 control set (ndLECs)
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.
Project description:FoxO transcription factors represent targets of the PI3K/PKB survival pathway controlling important biological processes such as stress responses, cell cycle progression, apoptosis, vascular remodelling and metabolism. Recent studies have demonstrated the existence of alternative mechanisms of FoxO-dependent gene expression beyond classical binding to a FoxO-responsive DNA binding element (FRE). Here we explored the relative contribution of those mechanisms by comparing the transcriptional responses to conditional activation of FoxO3 and a corresponding FRE-binding mutant in primary human endothelial cells. Microarray analysis revealed several functional gene clusters regulated in absence of an intact DNA-binding domain. Notably, both mutants triggered apoptosis albeit with different efficiencies. This was associated with regulation of overlapping and distinct proapototic gene clusters. Subsequent analysis demonstrated important roles for the Bcl2-like family members BIM and NOXA in this process. Remarkably, BIM was effectively induced by the FoxO3 FRE-binding mutant and BIM depletion could rescue its proapoptotic effect. Our study provides the first comprehensive analysis of alternatively regulated FoxO3 targets in primary cells and underscores the importance of such genes for endothelial function and integrity. HUVEC were infected in 4 independent experiments with either empty pBabe puro vector, pBP-FoxO3.A3.ER, or pBP FoxO3.A3.ER.H212R in three consecutive rounds and 72h post infection.
Project description:Beta-hydroxybutyrate (BHB) is a ketone body synthesized during fasting or strenuous exercise. Our previous study demonstrated that a cyclic ketogenic diet (KD), which induces BHB levels similar to fasting every other week, reduces midlife mortality and improves memory in aging mice. BHB actively regulates gene expression and inflammatory activation through non-energetic signaling pathways. Neither of these activities has been well-characterized in the brain and they may represent mechanisms by which BHB affects brain function during aging. First, we analyzed hepatic gene expression in an aging KD-treated mouse cohort using bulk RNA-seq. In addition to the downregulation of TOR pathway activity, cyclic KD reduces inflammatory gene expression in the liver. We observed via flow cytometry that KD also modulates age-related systemic T cell functions. Next, we investigated whether BHB affects brain cells transcriptionallyin vitro. Gene expression analysis in primary human brain cells (microglia, astrocytes, neurons) using RNA-seq shows that BHB causes a mild level of inflammation in all three cell types. However, BHB inhibits the more pronounced LPS-induced inflammatory gene activation in microglia. Furthermore, we confirmed that BHB similarly reduces LPS-induced inflammation in primary mouse microglia and bone marrow-derived macrophages (BMDMs). BHB is recognized as an inhibitor of histone deacetylase (HDAC), an inhibitor of NLRP3 inflammasome, and an agonist of the GPCR Hcar2. Nevertheless, in microglia, BHB's anti-inflammatory effects are independent of these known mechanisms. Finally, we examined the brain gene expression of 12-month-old male mice fed with one-week and one-year cyclic KD. While a one-week KD increases inflammatory signaling, a one-year cyclic KD reduces neuroinflammation induced by aging. In summary, our findings demonstrate that BHB mitigates the microglial response to inflammatory stimuli, like LPS, possibly leading to decreased chronic inflammation in the brain after long-term KD treatment in aging mice.
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.