Study of the Cellular Role of GRP78/BiP mono-ADP-ribosylation in UPR and Cancer

Mono-ADP-ribosylation is a reversible post-translational protein modification that modulates the function of proteins involved in different cellular processes, including signal transduction, protein transport, transcription, cell cycle regulation, DNA (deoxyribonucleic acid) repair and apoptosis. In mammals, mono-ADPribosylation is catalyzed by three different classes of enzymes: ARTCs, ARTDs, and members of the sirtuin family. In the present study, hARTC1-mediated mono-ADP-ribosylation was investigated in terms of the cellular compartments involved, target(s) and roles. The collected results demonstrated that hARTC1 protein and enzymatic activity is mainly localized to the endoplasmic reticulum (ER), in contrast to other ARTCs, which are either typically GPI-anchored enzymes in the plasma membrane, or secreted enzymes. Previous studies in my laboratory demonstrated that a protein macro domain was useful for the study of APD-ribosylation. The data reported here indicate, for the first time, that the macro domain can be used for immunofluorescence, allowing visualization of ADP-ribosylated proteins in intact cells, and in far-Western Blotting, allowing the detection of specific ADPribosylated targets. These methodologies were employed to demonstrate that the ER-localized chaperone, GRP78/BiP, was a prime target of hARTC1. A doubly mutated hARTC1 mutant was designed, and used as a specific control for hARTC1 expression. The mutant enzyme localized to the ER, but did not catalyze GRP78/BiP ADP-ribosylation. The demonstration that GRP78/BiP was mono-ADP-ribosylated by hARTC1 suggested that hARTC1 could be a key regulator of GRP78/BiP-mediated functions. Consistent with the key role of GRP78/BiP in the ER stress response, it was found that hARTC1 was activated during short-term cell treatment with ER stressors, resulting in acute GRP78/BiP ADP-ribosylation. However, the monoADP-ribosylation of the chaperone did not trigger an unfolded protein response. Recently, hARTC1 has been associated with cancer, suggesting a possible role in cell proliferation. In line with these findings, the results presented here demonstrated that hARTC1 over-expression inhibited cell proliferation

Sirtuins, aging, and cardiovascular risks

4noThe sirtuins comprise a highly conserved family proteins present in virtually all species from bacteria to mammals. Sirtuins are members of the highly conserved class III histone deacetylases, and seven sirtuin genes (sirtuins 1-7) have been identified and characterized in mammals. Sirtuin activity is linked to metabolic control, apoptosis, cell survival, development, inflammation, and healthy aging. In this review, we summarize and discuss the potential mutual relations between each sirtuin and cardiovascular health and the impact of sirtuins on oxidative stress and so age-related cardiovascular disorders, underlining the possibility that sirtuins will be novel targets to contrast cardiovascular risks induced by aging.openopenFavero, Gaia; Franceschetti, Lorenzo; Rodella, Luigi Fabrizio; Rezzani, RitaFavero, Gaia; Franceschetti, Lorenzo; Rodella, Luigi Fabrizio; Rezzani, Rit

A comparison of melatonin and α-lipoic acid in the induction of antioxidant defences in L6 rat skeletal muscle cells.

Aging is characterized by a progressive deterioration in physiological functions and metabolic processes. The loss of cells during aging in vital tissues and organs is related to several factors including oxidative stress and inflammation. Skeletal muscle degeneration is common in elderly people; in fact, this tissue is particularly vulnerable to oxidative stress since it requires large amounts of oxygen, and thus, oxidative damage is abundant and accumulates with increasing age. Melatonin (N-acetyl-5-methoxytryptamine) is a highly efficient scavenger of reactive oxygen species and it also exhibits beneficial anti-inflammatory and anti-aging effects. This study investigated the susceptibility of rat L6 skeletal muscle cells to an induced oxidative stress following their exposure to hydrogen peroxide (50 μM) and evaluating the potential protective effects of pre-treatment with melatonin (10 nM) compared to the known beneficial effect of alpha-lipoic acid (300 μM). Hydrogen peroxide-induced obvious oxidative stress; it increased the expression of tumour necrosis factor-alpha and in turn promoted nuclear factor kappa-B and overrode the endogenous defence mechanisms. Conversely, pre-treatment of the hydrogen peroxide-exposed cells to melatonin or alpha-lipoic acid increased endogenous antioxidant enzymes, including superoxide dismutase-2 and heme oxygenase-1; moreover, they ameliorated significantly oxidative stress damage and partially reduced alterations in the muscle cells, which are typical of aging. In conclusion, melatonin was equally effective as alpha-lipoic acid; it exhibited marked antioxidant and anti-aging effects at the level of skeletal muscle in vitro even when it was given in a much lower dose than alpha-lipoic acid

Browning of Adipose Tissue and Sirtuin Involvement

Obesity is an important risk factor for many diseases, including cardiovascular diseases, metabolic syndrome and cancers. Excessive dietary intake of caloric food results in its accumulation in white adipose tissue (WAT), whereas energy expenditure by fat utilization and oxidation predominately occurs in brown adipose tissue (BAT). Reducing obesity has become an important prevention strategy of research interest, focusing in the recent years, mainly on browning of WAT, the process during which the enhance of the mitochondria biogenesis occurs and then white adipocytes are converted to metabolically active beige adipocytes. Sirtuin1 (SIRT1), the most known isoform of sirtuin deacetylases, is implied in the browning of WAT process. In fact, it is a sensitive sensor of cell energy metabolism and, together with other sirtuin isoforms, contributes to this differentiation process. This chapter provides an overview about SIRT1 involvement in browning of WAT as a target molecule that can thereby contrast obesity

Hepatic Macrosteatosis Is Partially Converted to Microsteatosis by Melatonin Supplementation in ob/ob Mice Non-Alcoholic Fatty Liver Disease

Obesity is a common risk factor for non-alcoholic fatty liver disease (NAFLD). Currently, there are no specific treatments against NAFLD. Thus, examining any molecule with potential benefits against this condition emerged melatonin as a molecule that influences metabolic dysfunctions. The aim of this study was to determine whether melatonin would function against NAFDL, studying morphological, ultrastuctural and metabolic markers that characterize the liver of ob/ob mice

Analytical investigations on the Coronation Gospels manuscript

The Coronation Gospels or Kr\uf6nungsevangeliar is a manuscript kept in Vienna at the Kunsthistorisches Museum Wien, datable to the end of VIII century A.D. and produced at Charlemagne court. It is an example of a purple codex, i.e. its parchment is coloured in purple. It has to be considered as one of the most important medieval codices, according to its use to take oath in the coronation ceremony of kings and emperors of the Holy Roman Empire up to 1792. In order to gather information of the manufacture of the manuscript and its present conservation state, a diagnostic investigation campaign has been carried out in situ with totally non-invasive techniques. X-ray Fluorescence Spectrometry (XRF), UV-visible diffuse reflectance spectrophotometry with optical fibres (FORS), spectrofluorimetry, optical microscopy and multispectral analysis have been applied in order to identify the colourants used in the decoration of the manuscript, with the main concern to the dye used to impart the purple hue to the parchment. The information collected was useful in order to address some of the questions raised by art historians concerning its history

Tranexamic acid in open aortic aneurysm surgery: a randomised clinical trial

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Promising Antineoplastic Actions of Melatonin

Melatonin is an endogenous indoleamine with an incredible variety of properties and activities. In recent years, an increasing number of studies have investigated this indoleamine’s interaction with cancerous cells. In particular, it seems that melatonin not only has the ability to improve the efficacy of many drugs used in chemotherapy but also has a direct inhibitory action on neoplastic cells. Many publications underlined the ability of melatonin to suppress the proliferation of various cancer cells or to modulate the expression of membrane receptors on these cells, thereby reducing tumor aggressiveness to metastasize. In addition, while melatonin has antiapoptotic actions in normal cells, in many cancer cells it has proapoptotic effects; these dichotomous actions have gained the interest of researchers. The increasing focus on melatonin in the field of oncology and the growing number of studies on this topic require a deep understanding of what we already know about the antineoplastic actions of melatonin. This information would be of value for potential use of melatonin against neoplastic diseases