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Abstract: 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.
Keywords: Ageing Fibroblast Connective tissue Oxidative stress Protein expression Elastin
Published in RUNG: 23.08.2019; Views: 3237; Downloads: 0
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Abstract: 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.
Keywords: Ectopic calcification / Elastin / Fibroblast proteome / MRP6 / PXE
Published in RUNG: 23.08.2019; Views: 3409; Downloads: 0
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Abstract: 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.
Keywords: pathology, proteomics, fibrosis, rheumatology, cancer
Published in RUNG: 23.08.2019; Views: 2937; Downloads: 0
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Keywords: knowledge, expertise, collective learning, web, technoscientific citizenship
Published in RUNG: 23.08.2019; Views: 2459; Downloads: 0
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Abstract: Liver represents a suitable model for monitoring the effects of a diet, due to its key role in controlling the whole metabolism. Although no direct evidence has been reported so far that genetically modified (GM) food may affect health, previous studies on hepatocytes from young female mice fed on GM soybean demonstrated nuclear modifications involving transcription and splicing pathways. In this study, the effects of this diet were studied on liver of old female mice in order to elucidate possible interference with ageing. The morpho-functional characteristics of the liver of 24-month-old mice, fed from weaning on control or GM soybean, were investigated by combining a proteomic approach with ultrastructural, morphometrical and immunoelectron microscopical analyses. Several proteins belonging to hepatocyte metabolism, stress response, calcium signalling and mitochondria were differentially expressed in GM-fed mice, indicating a more marked expression of senescence markers in comparison to controls. Moreover, hepatocytes of GM-fed mice showed mitochondrial and nuclear modifications indicative of reduced metabolic rate. This study demonstrates that GM soybean intake can influence some liver features during ageing and, although the mechanisms remain unknown, underlines the importance to investigate the long-term consequences of GM-diets and the potential synergistic effects with ageing, xenobiotics and/or stress conditions.
Keywords: Genetically modified soybean, liver, mitochondria
Published in RUNG: 23.08.2019; Views: 3273; Downloads: 0
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