Methylglyoxal interaction with superoxide dismutase 1

Methylglyoxal (MG) is a highly reactive aldehyde spontaneously formed in human cells mainly as a by-product of glycolysis. Such endogenous metabolite reacts with proteins, nucleotides and lipids forming advanced glycation end-products (AGEs). MG binds to arginine, lysine and cysteine residues of proteins causing the formation of stable adducts that can interfere with protein function. Among the proteins affected by glycation, MG has been found to react with superoxide dismutase 1 (SOD1), a fundamental anti-oxidant enzyme that is abundantly expressed in neurons. Considering the high neuronal susceptibility to MG-induced oxidative stress, we sought to investigate by mass spectrometry and NMR spectroscopy which are the structural modifications induced on SOD1 by the reaction with MG. We show that MG reacts preferentially with the disulfide-reduced, demetallated form of SOD1, gradually causing its unfolding, and to a lesser extent, with the intermediate state of maturation – the reduced, zinc-bound homodimer – causing its gradual monomerization. These results suggest that MG could impair the correct maturation of SOD1 in vivo, thus both increasing cellular oxidative stress and promoting the cytotoxic misfolding and aggregation process of SOD1

Evidence of immune system morpho-functional damages induced by Cadmium in Apis mellifera

In previous researches severe damages induced by Cadmium (an ubiquitary environmental pollutant whose intracellular oxidative effects are increasingly lethal) exposure in human have been demonstrated. Morphologic effects were observed in Central Nervous System, liver, kidney, placenta. Recently, the involvement of immune system in Cadmium intoxication was demonstrated in mammalians; we, therefore, tried to evidence such effect in a simple model as Apis Mellifera. In this animal the immune system is represented by “fat bodies” which produce proteins active in defense against pathogenic agents. It is important to stress out that a dangerous syndrome causing the collapse of Apis mellifera hives has intensified recently, in Europe and North America. Current research in this field is oriented towards identifying a synergy of contributing factors to the weakening of the hive. In this paper, we aim to determine whether contamination by cadmium may have an immunosuppressive effect on the insect. Preliminary results denote that the heavy metal causes a severe damage in fat bodies, leading to substantial immunodeficiency in exposed bees, suggesting that in polluted areas the hives may have difficulty in dealing with pests and pathogens that threaten them

Cadmium effects on superoxide dismutase 1 in human cells revealed by NMR

Cadmium is a toxic pollutant that in recent decades has become more widespread in the environment due to anthropogenic activities, significantly increasing the risk of exposure. Concurrently, a continually growing body of research has begun to enumerate the harmful effects that this heavy metal has on human health. Consequently, additional research is required to better understand the mechanism and effects of cadmium at the molecular level. The main mechanism of cadmium toxicity is based on the indirect induction of severe oxidative stress, through several processes that unbalance the anti-oxidant cellular defence system, including the displacement of metals such as zinc from its native binding sites. Such mechanism was thought to alter the in vivo enzymatic activity of SOD1, one of the main antioxidant proteins of many tissues, including the central nervous system. SOD1 misfolding and aggregation is correlated with cytotoxicity in neurodegenerative diseases such as amyotrophic lateral sclerosis. We assessed the effect of cadmium on SOD1 folding and maturation pathway directly in human cells through in-cell NMR. Cadmium does not directly bind intracellular SOD1, instead causes the formation of its intramolecular disulfide bond in the zinc-bound form. Metallothionein overexpression is strongly induced by cadmium, reaching NMR-detectable levels. The intracellular availability of zinc modulates both SOD1 oxidation and metallothionein overexpression, strengthening the notion that zinc-loaded metallothioneins help maintaining the redox balance under cadmium-induced acute stress. Keywords: Cadmium, Superoxide dismutase 1, In-cell NMR, Oxidative stress, Metallothionei

Evidence of immune system morpho-functional damages induced by Cadmium in Apis mellifera

In previous researches severe damages induced by Cadmium (an ubiquitary environmental pollutant whose intracellular oxidative effects are increasingly lethal) exposure in human have been demonstrated. Morphologic effects were observed in Central Nervous System, liver, kidney, placenta. Recently, the involvement of immune system in Cadmium intoxication was demonstrated in mammalians; we, therefore, tried to evidence such effect in a simple model as Apis Mellifera. In this animal the immune system is represented by “fat bodies” which produce proteins active in defense against pathogenic agents. It is important to stress out that a dangerous syndrome causing the collapse of Apis mellifera hives has intensified recently, in Europe and North America. Current research in this field is oriented towards identifying a synergy of contributing factors to the weakening of the hive. In this paper, we aim to determine whether contamination by cadmium may have an immunosuppressive effect on the insect. Preliminary results denote that the heavy metal causes a severe damage in fat bodies, leading to substantial immunodeficiency in exposed bees, suggesting that in polluted areas the hives may have difficulty in dealing with pests and pathogens that threaten them

Conformational characterization of full-length X-chromosome-linked inhibitor of apoptosis protein (XIAP) through an integrated approach

The X-chromosome-linked inhibitor of apoptosis protein (XIAP) is a multidomain protein whose main function is to block apoptosis by caspase inhibition. XIAP is also involved in other signalling pathways, including NF-κB activation and copper homeostasis. XIAP is overexpressed in tumours, potentiating cell survival and resistance to chemotherapeutics, and has therefore become an important target for the treatment of malignancy. Despite the fact that the structure of each single domain is known, the conformation of the full-length protein has never been determined. Here, the first structural model of the full-length XIAP dimer, determined by an integrated approach using nuclear magnetic resonance, small-angle X-ray scattering and electron paramagnetic resonance data, is presented. It is shown that XIAP adopts a compact and relatively rigid conformation, implying that the spatial arrangement of its domains must be taken into account when studying the interactions with its physiological partners and in developing effective inhibitors

Autoimmune inflammatory reactions triggered by the COVID-19 genetic vaccines in terminally differentiated tissues

As a result of the spread of SARS-CoV-2, a global pandemic was declared. Indiscriminate COVID-19 vaccination has been extended to include age groups and naturally immune people with minimal danger of suffering serious complications due to COVID-19. Solid immuno-histopathological evidence demonstrates that the COVID-19 genetic vaccines can display a wide distribution within the body, affecting tissues that are terminally differentiated and far away from the injection site. These include the heart and brain, which may incur in situ production of spike protein eliciting a strong autoimmunological inflammatory response. Due to the fact that every human cell which synthesises non-self antigens, inevitably becomes the target of the immune system, and since the human body is not a strictly compartmentalised system, accurate pharmacokinetic and pharmacodynamic studies are needed in order to determine precisely which tissues can be harmed. Therefore, our article aims to draw the attention of the scientific and regulatory communities to the critical need for biodistribution studies for the genetic vaccines against COVID-19, as well as for rational harm-benefit assessments by age group

Solution structure and interaction with copper in vitro and in living cells of the first BIR domain of XIAP

Abstract The X-chromosome linked inhibitor of apoptosis (XIAP) is a multidomain metalloprotein involved in caspase inhibition and in copper homeostasis. It contains three zinc-binding baculoviral IAP repeats (BIR) domains, which are responsible for caspase interaction. Recently, it has been suggested that the BIR domains can bind copper, however high resolution data on such interaction is missing. Here we characterize by NMR the structural properties of BIR1 in solution, and the effects of its interaction with copper both in vitro and in physiological environments. BIR1 is dimeric in solution, consistent with the X-ray structure. Cysteine 12, located in the unfolded N-terminal region, has a remarkably low redox potential, and is prone to oxidation even in reducing physiological environments. Interaction of BIR1 with copper(II) results in the oxidation of cysteine 12, with the formation of either an intermolecular disulfide bond between two BIR1 molecules or a mixed disulfide bond with glutathione, whereas the zinc binding site is not affected by the interaction