Search results for "Selenoprotein"
showing 10 items of 12 documents
The tiny eukaryote Ostreococcus provides genomic insights into the paradox of plankton speciation
2007
The smallest known eukaryotes, at ≈1-μm diameter, are Ostreococcus tauri and related species of marine phytoplankton. The genome of Ostreococcus lucimarinus has been completed and compared with that of O. tauri . This comparison reveals surprising differences across orthologous chromosomes in the two species from highly syntenic chromosomes in most cases to chromosomes with almost no similarity. Species divergence in these phytoplankton is occurring through multiple mechanisms acting differently on different chromosomes and likely including acquisition of new genes through horizontal gene transfer. We speculate that this latter process may be involved in altering the cell-surface character…
Pathophysiology of non alcoholic fatty liver disease
2016
The physiopathology of fatty liver and metabolic syndrome are influenced by diet, life style and inflammation, which have a major impact on the severity of the clinicopathologic outcome of non-alcoholic fatty liver disease. A short comprehensive review is provided on current knowledge of the pathophysiological interplay among major circulating effectors/mediators of fatty liver, such as circulating lipids, mediators released by adipose, muscle and liver tissues and pancreatic and gut hormones in relation to diet, exercise and inflammation.
Optimization of Bacillus cereus Fermentation Process for Selenium Enrichment as Organic Selenium Source
2020
Selenium is an essential trace element and micronutrient for human health. Application of organic selenium in plants and microorganisms as trace element supplement is attracting more and more attention. In this study, Bacillus cereus, an important probiotic, was used for selenium enrichment with sodium selenite as selenium source. The growth curve of B. cereus was investigated, and 150 μg/ml was selected as the concentration of selenium for B. cereus fermentation. With application of response surface methodology, the optimal fermentation conditions were obtained as follows: inoculation quantity of 7%, culture temperature of 33°C, and shaking speed of 170 rpm, leading to the maximal selenium…
Gene Amplification-Associated Overexpression of the Selenoprotein tRNA Enzyme TRIT1 Confers Sensitivity to Arsenic Trioxide in Small-Cell Lung Cancer
2021
Simple Summary Small-cell lung cancer accounts for approximately 13% of all new lung cancer diagnoses, but in contrast to non-small-cell lung cancer, the implementation of targeted treatments in small-cell lung cancer has been limited, with little improvement in the clinical outcome in the last several decades. Exploring new pathways for targeted therapy, we have observed that extra-copies of the tRNA modifier TRIT1, involved in the translation of selenoproteins, confers sensitivity to arsenic trioxide in small-cell lung cancer. This finding could open a new therapeutic niche for a tumor type with such a dismal clinical course. The alteration of RNA modification patterns is emerging as a co…
The Effect of tRNA
2021
Transfer RNA[Ser]Sec carries multiple post-transcriptional modifications. The A37G mutation in tRNA[Ser]Sec abrogates isopentenylation of base 37 and has a profound effect on selenoprotein expression in mice. Patients with a homozygous pathogenic p.R323Q variant in tRNA-isopentenyl-transferase (TRIT1) show a severe neurological disorder, and hence we wondered whether selenoprotein expression was impaired. Patient fibroblasts with the homozygous p.R323Q variant did not show a general decrease in selenoprotein expression. However, recombinant human TRIT1R323Q had significantly diminished activities towards several tRNA substrates in vitro. We thus engineered mice conditionally deficient in Tr…
Desmin-related myopathy with mallory body-like inclusions is caused by mutations of the selenoprotein N gene
2004
Desmin-related myopathies (DRMs) are a heterogeneous group of muscle disorders, morphologically defined by intrasarcoplasmic aggregates of desmin. Mutations in the desmin and the alpha-B crystallin genes account for approximately one third of the DRM cases. The genetic basis of the other forms remain unknown, including the early-onset, recessive form with Mallory body-like inclusions (MB-DRMs), first described in five related German patients. Recently, we identified the selenoprotein N gene (SEPN1) as responsible for SEPN-related myopathy (SEPN-RM), a unique early-onset myopathy formerly divided in two different nosological categories: rigid spine muscular dystrophy and the severe form of c…
SELENIUM AND AUTOIMMUNE THYROIDITIS
2023
Selenium (Se) is an essential trace element of pivotal importance to human health. Se is incorporated into selenoproteins (SePs) which have pleiotropic effects, including antioxidant and anti-inflammatory effects, and in the production of active thyroid hormone. These findings may explain the relationship between Se deficiency and pathogenesis of various human diseases including thyroid disorder. In line with these observations, the therapeutic effectiveness of Se supplementation has already been reported in patients with various thyroid diseases. However, there are still controversial data about the optimal dose of Se to be administered, as well as the duration and efficacy of treatment an…
Selenium affects biosilica formation in the demosponge Suberites domuncula
2005
Selenium is a trace element found in freshwater and the marine environment. We show that it plays a major role in spicule formation in the demosponge Suberites domuncula. If added to primmorphs, an in vitro sponge cell culture system, it stimulates the formation of siliceous spicules. Using differential display of transcripts, we demonstrate that, after a 72-h exposure of primmorphs to selenium, two genes are up-regulated; one codes for selenoprotein M and the other for a novel spicule-associated protein. The deduced protein sequence of selenoprotein M (14 kDa) shows characteristic features of metazoan selenoproteins. The spicule-associated protein (26 kDa) comprises six characteristic repe…
Selenoproteins, cholesterol-lowering drugs, and the consequences: revisiting of the mevalonate pathway.
2004
3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) and peroxisome proliferator-activated receptor alpha activators (fibrates) are the backbone of pharmacologic hypercholesterolemia and dyslipidemia treatment. Many of their clinical effects, however, are still enigmatic. This article describes how a side road of the mevalonate pathway, characterized in recent years, can rationalize a major fraction of these unexplained observations. This side road is the enzymatic isopentenylation of selenocysteine-tRNA([Ser]Sec) (Sec-tRNA), the singular tRNA to decode the unusual amino acid selenocysteine. The functionally indispensable isopentenylation of Sec-tRNA requires a unique interm…
Prooxidative toxicity and selenoprotein suppression by cerivastatin in muscle cells
2012
Statins are the most widely used drugs for the treatment of hypercholesterolemia. In spite of their overall favorable safety profile, they do possess serious myotoxic potential, whose molecular origin has remained equivocal. Here, we demonstrate in cultivated myoblasts and skeletal muscle cells that cerivastatin at nanomolar concentrations interferes with selenoprotein synthesis and evokes a heightened vulnerability of the cells toward oxidative stressors. A correspondingly increased vulnerability was found with atorvastatin, albeit at higher concentrations than with cerivastatin. In selenium-saturated cells, cerivastatin caused a largely indiscriminate suppression of selenoprotein biosynth…