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Opis: Soft connective tissue calcification is not a passive process, but the consequence of metabolic changes of local mesenchymal cells that, depending on both genetic and environmental factors, alter the balance between pro- and anti-calcifying pathways. While the role of smooth muscle cells and pericytes in ectopic calcifications has been widely investigated, the involvement of fibroblasts is still elusive. Fibroblasts isolated from the dermis of pseudoxanthoma elasticum (PXE) patients and of patients exhibiting PXE-like clinical and histopathological findings offer an attractive model to investigate the mechanisms leading to the precipitation of mineral deposits within elastic fibers and to explore the influence of the genetic background and of the extracellular environment on fibroblast-associated calcifications, thus improving the knowledge on the role of mesenchymal cells on pathologic mineralization.
Ključne besede: fibroblasts, PXE, PXE-likedisorders, elastin, extracellularmatrix, ectopiccalcification, mesenchymal stromalcells
Objavljeno v RUNG: 23.08.2019; Ogledov: 3755; Prenosov: 0
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Ključne besede: Elastin Oxidative stress Matrix Gla protein Ectopic calcification Beta-thalassemia
Objavljeno v RUNG: 23.08.2019; Ogledov: 3925; Prenosov: 0
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Opis: Several studies have analyzed modulation of gene expression during physiological ageing with interesting, but often contradictory results, depending on the model used. In the present report we compare age-related metabolic and synthetic parameters in human dermal fibroblasts (HDF) isolated from young and old subjects (ex vivo ageing model) and cultured from early up to late cumulative population doublings (CPD) (in vitro ageing model) in order to distinguish changes induced in vivo by the aged environment and maintained in vitro, from those associated with cell senescence and progressive CPD. Results demonstrate that fibroblasts from aged donors, already at early CPD, exhibit an impaired redox balance, highlighting the importance of this parameter during ageing, even in the presence of standard environmental conditions, which are considered optimal for cell growth. By contrast, several proteins, as those related to heat shock response, or involved in endoplasmic reticulum and membrane trafficking, appeared differentially expressed only during in vitro ageing, suggesting that, at high CPD, the whole cell machinery becomes permanently altered. Finally, given the importance of the elastic component for a long-lasting connective tissue structural and functional compliance, this study focuses also on elastin and fibulin-5 synthesis and deposition, demonstrating a close relationship between fibulin-5 and ageing.
Ključne besede: Ageing Fibroblast Connective tissue Oxidative stress Protein expression Elastin
Objavljeno v RUNG: 23.08.2019; Ogledov: 3955; Prenosov: 0
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Opis: Pseudoxanthoma elasticum (PXE) is a genetic disorder associated to mutations in the ABCC6 gene; however, the pathogenetic mechanisms leading to elastic fibre calcifications and to clinical manifestations are still unknown. Dermal fibroblasts, directly involved in the production of the extracellular milieu, have been isolated from healthy subjects and from patients affected by PXE, cultured in vitro and characterized for their ability to produce reactive oxygen species, for structural and functional properties of their cell membranes, for changes in their protein profile. Data demonstrate that oxidative stress has profound and endurable consequences on PXE fibroblast phenotype being responsible for: reduced levels of global DNA methylation, increased amount of carbonylated proteins and of lipid peroxidation products, altered structural properties of cell membranes, modified protein expression. Data shed new light on the pathogenetic pathways in PXE, by identifying a network of proteins affecting elastic fibre calcification through inefficient vitamin K recycling, and highlight the role of differentially expressed proteins as targets for validating the efficacy of future therapeutic strategies aiming to delay and/or revert the pathologic phenotype of PXE fibroblasts. Moreover, data open new perspectives for investigating PXE-like phenotypes in the absence of ABCC6 mutations.
Ključne besede: Ectopic calcification / Elastin / Fibroblast proteome / MRP6 / PXE
Objavljeno v RUNG: 23.08.2019; Ogledov: 4047; Prenosov: 0
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Opis: Connective tissue consists of cells separated by the extracellular matrix, whose composition and amount vary according to age, to functional requirements, and to the presence of pathologic conditions. Within this non-random macromolecular assembly, collagens, elastin, proteoglycans and structural glycoproteins are mutually interdependent and modifications of one component, by extrinsic (environmental) and/or intrinsic (systemic, genetic, age-related) factors, may have consequences on the tissue as a whole. Since decades, different microscopical techniques have been applied mainly for diagnostic purposes and for detailed descriptions of changes occurring in cells and in matrix components. More recently, in order to dissect the molecular complexity of the matrix network, to analyse the interactions between cells and matrix and to look for modulators of cell phenotype, histomorphologic investigations have been implemented with proteomic studies that allow to identify possible diagnostic markers, and to better understand patho-mechanisms enabling the design of novel therapeutic strategies. Therefore, the progressively expanding, although incomplete, knowledge on connective tissue biology, sheds new light on the pathogenesis of diseases affecting single molecules (i.e. collagenopathies, mucopolysaccharidoses, elastinopathies) and discloses the importance of matrix components as fundamental regulators of cell phenotype, in relation, for instance, to the aging process and/or to cancer development and progression. Few examples will be presented demonstrating the promises of proteomics as a technique leading to the discovery of new therapies and possibly to the development of individualized treatments for a better patient care.
Ključne besede: pathology, proteomics, fibrosis, rheumatology, cancer
Objavljeno v RUNG: 23.08.2019; Ogledov: 3540; Prenosov: 0
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