A compilation of microarray gene expression profiles to explore the biological characteristics of low-grade astrocytomes

info:eu-repo/semantics/nonPublishe

Contribution of the plasmin/matrix metalloproteinase cascade to the retraction of human fibroblast populated collagen lattices.

To assess the contribution of the plasmin/matrix metalloproteinase cascade in lattices retraction, human gingival fibroblast-populated collagen lattices were supplemented with plasminogen. The rate of lattice retraction was enhanced by addition of plasminogen. This effect was concomitant to plasmin generation, prostromelysin-1 and procollagenase activation. Plasminogen-mediated initiation of that proteolytic cascade was accompanied by conspicuous changes in cell morphology and collagen fibers organization. At day 1 of culture fibroblasts shifted from a rounded (control) to an elongated (in presence of plgn) shape. At the latest stage of retraction, intense vacuolization around fibroblasts was noticed in plgn-supplemented lattices which paralleled the increased collagen degradation. Plgn-enhancing influence on the initial phase of lattice retraction could be totally annihilated by either aprotinin or Batimastat. Those data emphasize the crucial importance of the plasmin-MMP proteolytic cascade in granulation tissue retraction in a healing wound

Involvement of fibronectin type II repeats in the efficient inhibition of gelatinases A and B by long-chain unsaturated fatty acids

The matrix metalloproteinases gelatinase A (MMP-2) and gelatinase B (MMP-9) are implicated in the physiological and pathological breakdown of several extracellular matrix proteins. In the present study, we show that long-chain fatty acids (e.g. oleic acid, elaidic acid, and cis- and trans-parinaric acids) inhibit gelatinase A as well as gelatinase B with K-i values in the micromolar range but had only weak inhibitory effect on collagenase-1 (MMP-1), as assessed using synthetic or natural substrates, The inhibition of gelatinases depended on fatty acid chain length (with C18 > C16, C14, and C10), and the presence of unsaturations increased their inhibitory capacity on both types of gelatinase, Ex vivo experiments on human shin tissue sections have shown that micromolar concentrations of a long-chain unsaturated fatty acid (elaidic acid) protect collagen and elastin fibers against degradation by gelatinases A and B, respectively. In order to understand why gelatinases are more susceptible than collagenase-1 to inhibition by long-chain fatty acids, the possible role of the fibronectin-like domain (a domain unique to gelatinases) in binding inhibitory fatty acids was investigated. Affinity and kinetic studies with a recombinant fibronectin-like domain of gelatinase A and with a recombinant mutant of gelatinase A from which this domain had been deleted pointed to an interaction of long-chain fatty acids with the fibronectin-like domain of the protease, Surface plasmon resonance studies on the interaction of long-chain fatty acids with the three individual type II modules of the fibronectin-like domain of gelatinase A revealed that the first type II module is primarily responsible for binding these compounds

Formyl peptide receptor-like 2 is expressed and functional in plasmacytoid dendritic cells, tissue-specific macrophage subpopulations, and eosinophils.

The formyl peptide receptor (FPR) is a key player in innate immunity and host defense mechanisms. In humans and other primates, a cluster of genes encodes two related receptors, FPR-like 1 and FPR-like 2 (FPRL1 and FPRL2). Despite their high sequence similarity, the three receptors respond to different sets of ligands and display a different expression pattern in leukocyte populations. Unlike FPR and FPRL1, FPRL2 is absent from neutrophils, and two endogenous peptide agonists, F2L and humanin, were recently described. In the present work, we investigated the detailed functional distribution of FPRL2 in leukocytes by quantitative PCR, flow cytometry, immunohistochemistry, and chemotaxis assays, with the aim of raising hypotheses regarding its potential functions in the human body. We describe that FPRL2 is highly expressed and functional in plasmacytoid dendritic cells and up-regulated upon their maturation. FPRL2 is also expressed in eosinophils, which are recruited but do not degranulate in response to F2L. FPRL2 is expressed and functional in macrophages differentiated from monocytes in vitro in different conditions. However, in vivo, only specific subsets of macrophages express the receptor, particularly in the lung, colon, and skin, three organs chronically exposed to pathogens and exogenous aggressions. This distribution and the demonstration of the production of the F2L peptide in mice underline the potential role of FPRL2 in innate immunity and possibly in immune regulation and allergic diseases.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

A genomic-based approach identifies FXYD domain containing ion transport regulator 2 (FXYD2)gamma as a pancreatic beta cell-specific biomarker.

AIMS/HYPOTHESIS: Non-invasive imaging of the pancreatic beta cell mass (BCM) requires the identification of novel and specific beta cell biomarkers. We have developed a systems biology approach to the identification of promising beta cell markers. METHODS: We followed a functional genomics strategy based on massive parallel signal sequencing (MPSS) and microarray data obtained in human islets, purified primary rat beta cells, non-beta cells and INS-1E cells to identify promising beta cell markers. Candidate biomarkers were validated and screened using established human and macaque (Macacus cynomolgus) tissue microarrays. RESULTS: After a series of filtering steps, 12 beta cell-specific membrane proteins were identified. For four of the proteins we selected or produced antibodies targeting specifically the human proteins and their splice variants; all four candidates were confirmed as islet-specific in human pancreas. Two splice variants of FXYD domain containing ion transport regulator 2 (FXYD2), a regulating subunit of the Na(+)-K(+)-ATPase, were identified as preferentially present in human pancreatic islets. The presence of FXYD2gammaa was restricted to pancreatic islets and selectively detected in pancreatic beta cells. Analysis of human fetal pancreas samples showed the presence of FXYD2gammaa at an early stage (15 weeks). Histological examination of pancreatic sections from individuals with type 1 diabetes or sections from pancreases of streptozotocin-treated Macacus cynomolgus monkeys indicated a close correlation between loss of FXYD2gammaa and loss of insulin-positive cells. CONCLUSIONS/INTERPRETATION: We propose human FXYD2gammaa as a novel beta cell-specific biomarker.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Misexpression of inactive genes in whole blood is associated with nearby rare structural variants.

Gene misexpression is the aberrant transcription of a gene in a context where it is usually inactive. Despite its known pathological consequences in specific rare diseases, we have a limited understanding of its wider prevalence and mechanisms in humans. To address this, we analyzed gene misexpression in 4,568 whole-blood bulk RNA sequencing samples from INTERVAL study blood donors. We found that while individual misexpression events occur rarely, in aggregate they were found in almost all samples and a third of inactive protein-coding genes. Using 2,821 paired whole-genome and RNA sequencing samples, we identified that misexpression events are enriched in cis for rare structural variants. We established putative mechanisms through which a subset of SVs lead to gene misexpression, including transcriptional readthrough, transcript fusions, and gene inversion. Overall, we develop misexpression as a type of transcriptomic outlier analysis and extend our understanding of the variety of mechanisms by which genetic variants can influence gene expression