Project description:Natural killer (NK) cells are lymphocytes that participate in immune responses through their cytotoxic activity and secretion of cytokines and chemokines. They can be activated by interaction with ligands on target cells or by soluble mediators such as cytokines. In addition, soluble HLA-G, a major histocompatibility complex molecule secreted by fetal trophoblast cells during early pregnancy, stimulates resting NK cells to secrete proinflammatory and proangiogenic factors. Human NK cells are abundant in uterus, where they remain after implantation. Soluble HLA-G is endocytosed into early endosomes of NK cells where its receptor, CD158d, initiates a signaling cascade through DNA-PKcs, Akt and NF-kB3. The physiological relevance of this endosomal signaling pathway, and how the fate and function of NK cells during early pregnancy is regulated, is unknown. Here we show that soluble agonists of CD158d trigger DNA damage response signaling and p21 (CIP1/WAF1) expression to promote senescence in primary NK cells. CD158d engagement resulted in morphological alterations in cell size and shape, chromatin remodeling, and survival in the absence of proliferation, all hallmarks of senescence. Microarray analysis revealed a senescence signature of upregulated genes upon sustained activation through CD158d. The proinflammatory and proangiogenic factors secreted by these metabolically active NK cells are part of a senescence associated secretory phenotype (SASP) that promoted tissue remodeling and angiogenesis as assessed by functional readouts of vascular permeability and endothelial cell tube formation. We propose that ligand-induced senescence is a molecular switch for the sustained activation of NK cells in response to soluble HLA-G for the purpose of remodeling the maternal vasculature in early pregnancy. Time series (4 hr, 16 hr, 64 hr) of NK cells treated with agonist (anti-CD158d mAb) or control. NK cells were from 4 donors.
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.
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. Two-condition experiment, Normoxic MSCs vs. Hypoxic MSCs.
Project description:Natural killer (NK) cells are lymphocytes that participate in immune responses through their cytotoxic activity and secretion of cytokines and chemokines. They can be activated by interaction with ligands on target cells or by soluble mediators such as cytokines. In addition, soluble HLA-G, a major histocompatibility complex molecule secreted by fetal trophoblast cells during early pregnancy, stimulates resting NK cells to secrete proinflammatory and proangiogenic factors. Human NK cells are abundant in uterus, where they remain after implantation. Soluble HLA-G is endocytosed into early endosomes of NK cells where its receptor, CD158d, initiates a signaling cascade through DNA-PKcs, Akt and NF-kB3. The physiological relevance of this endosomal signaling pathway, and how the fate and function of NK cells during early pregnancy is regulated, is unknown. Here we show that soluble agonists of CD158d trigger DNA damage response signaling and p21 (CIP1/WAF1) expression to promote senescence in primary NK cells. CD158d engagement resulted in morphological alterations in cell size and shape, chromatin remodeling, and survival in the absence of proliferation, all hallmarks of senescence. Microarray analysis revealed a senescence signature of upregulated genes upon sustained activation through CD158d. The proinflammatory and proangiogenic factors secreted by these metabolically active NK cells are part of a senescence associated secretory phenotype (SASP) that promoted tissue remodeling and angiogenesis as assessed by functional readouts of vascular permeability and endothelial cell tube formation. We propose that ligand-induced senescence is a molecular switch for the sustained activation of NK cells in response to soluble HLA-G for the purpose of remodeling the maternal vasculature in early pregnancy.
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: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: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.
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.