Cardiac myoglobin participates in the metabolic pathway of selenium in rats

Ultrasensitive determination of selenium in food samples and its speciation in water and beverages using thiosemicarbazide-incorporated graphene and total-reflection X-ray fluorescence spectrometry

The paper presents a new analytical procedure for the determination and speciation of trace and ultratrace selenium in water, beverages, seafood, milk, and vegetables. The developed method is based on the dispersive micro-solid phase extraction with the use of new thiosemicarbazide-incorporated graphene as a solid sorbent, in combination of the total-reflection X-ray fluorescence spectrometry (TXRF). As a result, we have created an auspicious analytical tool for fast and sensitive analysis of samples with a complex matrix. Regardless of the specimen type, the method is characterized by a very low detection limit of 1.7 pg mL-1 and high precision. The developed strategy allowed us to solve common problems associated with selenium loss during the sample preparation for the TXRF measurement and also improve its performance toward the analysis of beverages and high saline/solid samples, which may even be impossible to perform using standard sample preparation procedures for a TXRF measurement.

Comparison of Muscle Color and Total Selenium Concentrations Between Spotted Mackerel Scomber australasicus and Pacific Mackerel S. japonicus

Selenoneine is a selenium-containing imidazole compound in the blood and tissues of tuna and other marine fish that has strong free-radical scavenging activity. This compound may have antioxidant functions, i.e., preventing metmyoglobin formation in fish muscle, which affects meat quality. This study examined the relationship between meat color and total selenium concentration in the muscle of two Scomber species, spotted mackerel (Scomber australasicus) and Pacific mackerel (S. japonicus), to assess the role of selenium as an antioxidant preventing meat discoloration. The color of chilled and frozen-thawed muscle was compared between spotted mackerel and Pacific mackerel. The a* values, indicating the red-green component of color, of the white and red muscle of spotted mackerel were higher than those of Pacific mackerel (p < 0.05). We also analyzed the blood selenium concentration of Pacific mackerel according to the L* value and protein concentration in the blood during spawning migration in June. The blood selenium concentration was negatively correlated with the L* value (r =  - 0.46) and blood protein concentration (r =  - 0.56). The blood selenium concentration in summer was related to the brightness of the muscle surface and blood protein concentration, suggesting that it is responsible for deterioration of meat quality.These findings suggest that antioxidant properties of selenium prevent the mackerel muscle discoloration that can occur during chilled and frozen storage.

Selenium Attenuates Doxorubicin-Induced Cardiotoxicity Through Nrf2-NLRP3 Pathway

Selenium (Se), an essential nutrient for humans, has been reported to possess cardioprotective effect. However, the protective effects of Se against doxorubicin (DOX)-induced cardiotoxicity and the underlying mechanism are rarely reported. In this study, we sought to explore whether Se protected against DOX-induced cardiotoxicity by inhibiting Nrf2-NLRP3 pathway. We found that Se treatment effectively alleviated DOX-induced myocardial dysfunctions, decreasing plasma markers associated with myocardial injury. Moreover, Se treatment significantly inhibited DOX-induced oxidative damages and pro-inflammatory cytokine expression in heart tissues. Furthermore, Se treatment markedly promoted the expression of Nrf2 and prevented the activation of NLRP3 inflammasome. Importantly, suppression of Nrf2 abolished the cardioprotective effects of Se and diminished the inhibition of Se on NLRP3 inflammasome. Collectively, our study demonstrated that Se might protect against DOX-induced cardiotoxicity via regulating Nrf2-NLRP3 pathway. Se supplementation may be a potential therapeutic strategy to protect against DOX-induced cardiac injury.

Peptidyl-prolyl cis-trans isomerase A participates in the selenium transport into the rat brain

Selenium, an essential micronutrient, plays vital roles in the brain. Selenoprotein P (SELENOP), a major plasma selenoprotein, is thought to transport selenium to the brain. However, Selenop-knockout mice fed a diet containing an adequate amount of selenium shows no objective neurological dysfunction which is observed in the selenium-deficient diet-fed Selenop-knockout mice. This fact indicated that selenium from low-mass selenium-source compounds can be transported by SELENOP-independent alternative pathways to the brain. In this study, to obtain the basic information about the SELENOP-independent transport pathways, we performed ex vivo experiments in which the rat brain cell membrane fraction was analyzed to find selenium-binding and/or -interactive proteins using its reactive metabolic intermediate, selenotrisulfide (STS), and MALDI TOF-mass spectrometry. Several membrane proteins with the cysteine (C) thiol were found to be reactive with STS through the thiol-exchange reaction. One of the C-containing proteins in the brain cell membrane fraction was identified as peptidyl-prolyl cis-trans isomerase (PPIase) A from tryptic fragmentation experiments and database search. Among the 4 C residues in rat PPIase A, 21st C was proved to react with STS by assessment using C mutated recombinant proteins. PPIase A is ubiquitously expressed and also associates with a variety of biologically important events such as immunomodulation, intracellular signaling, transcriptional regulation and protein trafficking. Consequently, PPIase A was thought to participate in the selenium transport into the rat brain.

Selenium Supplementation Protects Against Lipopolysaccharide-Induced Heart Injury via Sting Pathway in Mice

Sepsis-induced myocardial dysfunctions are associated with high morbidity and mortality. Selenium, an essential trace element, has been reported to exert anti-inflammation, anti-oxidative stress, and anti-apoptosis. However, the protective effects of selenium on LPS-induced heart injury are still poorly illustrated. Therefore, in the present study, we sought to explore the effects of selenium pretreatment on LPS-induced myocardial injury in mice. We firstly found that selenium pretreatment significantly improved markers of myocardial injury and alleviated LPS-induced myocardial dysfunctions. Moreover, selenium supplementation reduced pro-inflammatory cytokines expression, decreased oxidative stress, and inhibited myocardial apoptosis. In addition, selenium supplementation inactivated the Sting pathway. In conclusion, our study suggests that selenium exerts protective effects on LPS-induced myocardial injury, and the underlying molecular mechanism may be related to the inactivation of Sting pathway, implying a potential therapy for sepsis-induced myocardial dysfunctions.

Expression Profile Analysis of Selenium-Related Genes in Peripheral Blood Mononuclear Cells of Patients with Keshan Disease

Keshan disease (KD) is an endemic cardiomyopathy, which mainly occurs in China. Selenium deficiency is believed to play an important role in the pathogenesis of KD, but the molecular mechanism of selenium-induced damage remains unclear. To identify the key genes involved in selenium-induced damage, we compared the expression profiles of selenium-related genes between patients with KD and normal controls. Total RNA was isolated, amplified, labeled, and hybridized to Agilent human 4 × 44 K whole genome microarrays. Selenium-related genes were screened using the Comparative Toxicogenomics Database. The microarray data were subjected to single-gene and gene ontology (GO) expression analysis using R Studio and Gene Set Enrichment Analysis (GSEA) software. Quantitative real-time PCR was conducted to validate the microarray results. We identified 16 upregulated and 11 downregulated selenium-related genes in patients. These genes are involved in apoptosis, metabolism, transcription regulation, ion transport, and growth and development. Of the significantly enriched GO categories in KD patients, we identified four apoptosis-related, two metabolism-related, four growth and development-related, and four ion transport-related GOs. Based on our results, we suggest that selenium might contribute to the development of KD through dysfunction of selenium-related genes involved in apoptosis, metabolism, ion transport, and growth and development in the myocardium.