Down Regulation of a Matrix Degrading Cysteine Protease Cathepsin L, by Acetaldehyde: Role of C/EBPα

BACKGROUND: The imbalance between extra cellular matrix (ECM) synthesis and degradation is critical aspect of various hepatic pathologies including alcohol induced liver fibrosis. This study was carried out to investigate the effect of acetaldehyde on expression of an extra cellular matrix degrading protease cathepsin L (CTSL) in HepG2 cells. METHODOLOGY AND RESULTS: We measured the enzymatic activity, protein and, mRNA levels of CTSL in acetaldehyde treated and untreated cells. The binding of CAAT enhancer binding protein α (C/EBP α) to CTSL promoter and its key role in the transcription from this promoter and conferring responsiveness to acetaldehyde was established by site directed mutagenesis, electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP) assays and siRNA technology. Acetaldehyde treatment significantly decreased CTSL activity and protein levels in HepG2 cells. A similar decrease in the mRNA levels and promoter activity was also observed. This decrease by acetaldehyde was attributed to the fall in the liver enriched transcription factor C/EBP α levels and it's binding to the CTSL promoter. Mutagenesis of C/EBP α binding motifs revealed the key role of this factor in CTSL transcription as well as conferring responsiveness to acetaldehyde. The siRNA mediated silencing of the C/EBP α expression mimicked the effect of acetaldehyde on CTSL levels and its promoter activity. It also abolished the responsiveness of this promoter to acetaldehyde. CONCLUSION: Acetaldehyde down regulates the C/EBP α mediated CTSL expression in hepatic cell lines. The decreased expression of CTSL may at least in part contribute to ECM deposition in liver which is a hallmark of alcoholic liver fibrosis

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Lethal chlorine concentrations for the pearl oyster Pinctada radiata (Leach, 1814)

WOS: 000174339400024In this study, the lethal chlorine concentrations (LC) and residual chlorine concentrations in water for a fouling organism, the pearl oyster Pinctada radiata (Leach, 1814) [Avicula], were investigated during May 1999-April 2000. The study was carried out under laboratory conditions at 20 C. Acute toxicity tests were conducted under a flow through system by using continuous application of chlorine according to bioassay test methods. Test solutions were made by using an appropriate amount of sodium hypochlorite (NaOCl). According to the results, the 24h-LC50 was 1.75 mgl(-1) and the residual chlorine was 0.47 mgl(-1) for LC50 of Pinctada radiata

Generation of mouse hybridomas secreting anti-salmonella enteritidis antibodies and their preliminary characterization [Anti-salmonella enteritidis antikorlari{dotless} salgi{dotless}layan fare hibridomalari{dotless}ni{dotless}n geliştirilmesi ve ön karakterizasyonlari{dotless}]

BALB/c mice were intraperitoneally immunized with inactivated bacteria for generation of monoclonal anti-S. Enteritidis antibody. The spleen cells of the highest responder animal at fifth immunization were used as the fusion partner of the mouse Sp2/0 myeloma cells. A total of 6 stable hybridomas secreting IgM and IgG isotype antibodies were obtained. These hybridomas were found to be reactive with three S. Enteritidis antigens having relative molecular weights of 73, 59 and 42kDa in Western blot analysis. The 59kDa molecule corresponds to the flagellin protein. From this preliminary study, it can be concluded that further investigations are necessary to obtain monoclonal hybrid cells secreting monoepitopic and monoisotypic antibody by subcloning of the parental hybridomas

Mechanical properties and electrochemical behavior of porous Ti-Nb biomaterials

PMID = 3004114