From selenium to selenoproteins: synthesis, identity, and their role in human health

Interplay between diphenyl diselenide and copper: Impact on D. melanogaster survival, behavior, and biochemical parameters

Copper (Cu2+) is a biologically essential element that participates in numerous physiological processes. However, elevated concentrations of copper have been associated with cellular oxidative stress and neurodegenerative diseases. Organo‑selenium compounds such as diphenyl diselenide (DPDS) have in vitro and in vivo antioxidant properties. Hence, we hypothesized that DPDS may modulate the toxicity of Cu2+ in Drosophila melanogaster. The acute effects (4 days of exposure) caused by a high concentration of Cu2+ (3 mM) were studied using endpoints of toxicity such as survival and behavior in D. melanogaster. The potential protective effect of low concentration of DPDS (20 μM) against Cu2+ was also investigated. Adult flies aged 1-5 days post-eclosion (both sexes) were divided into four groups: Control, DPDS (20 μM), CuSO4 (3 mM), and the combined exposure of DPDS (20 μM) and CuSO4 (3 mM). Survival, biochemical, and behavioral parameters were determined. Co-exposure of DPDS and CuSO4 increased acetylcholinesterase (AChE) activity and the generation of reactive oxygen species (ROS as determined by DFCH oxidation). Contrary to our expectation, the co-exposure reduced survival, body weight, locomotion, catalase activity, and cell viability in relation to control group. Taken together, DPDS potentiated the Cu2+ toxicity.

Selenium Ameliorates Acetaminophen-Induced Oxidative Stress via MAPK and Nrf2 Pathways in Mice

Overdose of acetaminophen (paracetamol), a widely used non-prescriptive analgesic and antipyretic medication, is one of the main causes of drug-induced acute liver failure around the world. Oxidative stress contributes to this hepatotoxicity. Antioxidants are known to protect the liver from oxidative stress. Selenium, a potent antioxidant, is a commonly used micronutrient. Here, we evaluated the protective effect of selenium on acetaminophen-induced hepatotoxicity. Treating Wistar albino mice with sodium selenite (1 mg/kg) before or after inducing hepatotoxicity with acetaminophen (150 mg/kg) significantly reduced the levels of liver injury biomarkers such as serum glutamate oxaloacetate transaminase and serum glutamate pyruvate transaminase. In addition, selenium-treated mice showed decreased levels of oxidative stress markers such as protein carbonyls and myeloperoxidase. Acetaminophen treatment stimulated all three mitogen-activated protein kinases (MAPKs) and Keap1 and decreased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 in liver and in isolated mouse peritoneal macrophages, which was reversed by selenium treatment. Our findings suggest that the reactive oxygen species-mediated Nrf2 and MAPK pathways are critical players in acetaminophen-induced hepatotoxicity. These key findings offer an alternative therapeutic target for addressing acetaminophen-induced hepatotoxicity.

Understanding the Roles of Selenium on Thyroid Hormone-Induced Thermogenesis in Adipose Tissue

Brown adipose tissue (BAT) and white adipose tissue (WAT) are known to regulate lipid metabolism. A lower amount of BAT compared to WAT, along with adipose tissue dysfunction, can result in obesity. Studies have shown that selenium supplementation protects against adipocyte dysfunction, decreases WAT triglycerides, and increases BAT triiodothyronine (T3). In this review, we discuss the relationship between selenium and lipid metabolism regulation through selenoprotein deiodinases and the role of deiodinases and thyroid hormones in the induction of adipose tissue thermogenesis. Upon 22 studies included in our review, we found that studies investigating the relationship between selenium and deiodinases demonstrated that selenium supplementation affects the iodothyronine deiodinase 2 (DIO2) protein and the expression of its associated gene, DIO2, proportionally. However, its effect on DIO1 is inconsistent while its effect on DIO3 activity is not detected. Studies have shown that the activity of deiodinases especially DIO2 protein and DIO2 gene expression is increased along with other browning markers upon white adipose tissue browning induction. Studies showed that thermogenesis is stimulated by the thyroid hormone T3 as its activity is correlated to the expression of other thermogenesis markers. A proposed mechanism of thermogenesis induction in selenium supplementation is by autophagy control. However, more studies are needed to establish the role of T3 and autophagy in adipose tissue thermogenesis, especially, since some studies have shown that thermogenesis can function even when T3 activity is lacking and studies related to autophagy in adipose tissue thermogenesis have contradictory results.

Glutathione peroxidase (GPX1) - Selenocysteine metabolism preserves the follicular fluid's (FF) redox homeostasis via IGF-1- NMD cascade in follicular ovarian cysts (FOCs)

Follicular ovarian cysts (FOCs) are characterized by follicles in the ovaries that are >20 mm in diameter and persist for >10 days without the corpus luteum, leading to anovulation, dysregulation of folliculogenesis and subfertility in humans and livestock species. Despite their clinical significance, the precise impact of FOCs on oocyte reserve, maturation, and quality still needs to be explored. While FOCs are observed in both human and livestock populations, they are notably prevalent in livestock species. Consequently, livestock species serve as valuable models for investigating the molecular intricacies of FOCs. Thus, in this study, using goat FOCs, we performed integrated proteomic, metabolomic and functional analyses to demonstrate that oocyte maturation is hampered due to increased reactive oxygen species (ROS) in FOCs follicular fluid (FF) via downregulation of glutathione peroxidase (GPX1), a critical antioxidant seleno enzyme required to negate oxidative stress. Notably, GPX1 reduction was positively correlated with the FF's decline of free selenium and selenocysteine metabolic enzymes, O-phosphoryl-tRNA (Sec) selenium transferase (SEPSECS) and selenocysteine lyase (SCLY) levels. Adding GPX1, selenocysteine, or selenium to the culture media rescued the oocyte maturation abnormalities caused by FOCs FF by down-regulating the ROS. Additionally, we demonstrate that substituting GPX1 regulator, Insulin-like growth factor-I (IGF-1) in the in vitro maturation media improved the oocyte maturation in the cystic FF by down-regulating the ROS activity via suppressing Non-sense-mediated decay (NMD) of GPX1. In contrast, inhibition of IGF-1R and the target of rapamycin complex 1 (mTORC1) hampered the oocyte maturation via NMD up-regulation. These findings imply that the GPX1 regulation via selenocysteine metabolism and the IGF-1-mediated NMD may be critical for the redox homeostasis of FF. We propose that GPX1 enhancers hold promise as therapeutics for enhancing the competence of FOCs oocytes. However, further in vivo studies are necessary to validate these findings observed in vitro.

The Potential of Selenium-Based Therapies for Ocular Oxidative Stress

Oxidative stress plays a critical role in the development of chronic ocular conditions including cataracts, age-related macular degeneration, and diabetic retinopathy. There is a need to explore the potential of topical antioxidants to slow the progression of those conditions by mediating oxidative stress and maintaining ocular health. Selenium has attracted considerable attention because it is a component of selenoproteins and antioxidant enzymes. The application of selenium to a patient can increase selenoprotein expression, counteracting the effect of reactive oxygen species by increasing the presence of antioxidant enzymes, and thus slowing the progression of chronic ocular disorders. Oxidative stress effects at the biomolecular level for prevalent ocular conditions are described in this review along with some of the known defensive mechanisms, with a focus on selenoproteins. The importance of selenium in the eye is described, along with a discussion of selenium studies and uses. Selenium's antioxidant and anti-inflammatory qualities may prevent or delay eye diseases. Recent breakthroughs in drug delivery methods and nanotechnology for selenium-based ocular medication delivery are enumerated. Different types of selenium may be employed in formulations aimed at managing ocular oxidative stress conditions.

Metal mixture exposures and serum lipid levels in childhood: the Rhea mother-child cohort in Greece

BACKGROUND

Growing evidence suggests that cardiovascular disease develops over the lifetime, often beginning in childhood. Metal exposures have been associated with cardiovascular disease and important risk factors, including dyslipidemia, but prior studies have largely focused on adult populations and single metal exposures.

OBJECTIVE

To investigate the individual and joint impacts of multiple metal exposures on lipid levels during childhood.

METHODS

This cross-sectional study included 291 4-year-old children from the Rhea Cohort Study in Heraklion, Greece. Seven metals (manganese, cobalt, selenium, molybdenum, cadmium, mercury, and lead) were measured in whole blood using inductively coupled plasma mass spectrometry. Serum lipid levels included total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol. To determine the joint and individual impacts of child metal exposures (log2-transformed) on lipid levels, Bayesian kernel machine regression (BKMR) was employed as the primary multi-pollutant approach. Potential effect modification by child sex and childhood environmental tobacco smoke exposure was also evaluated.

RESULTS

BKMR identified a positive association between the metal mixture and both total and LDL cholesterol. Of the seven metals examined, selenium (median 90.6 [IQR = 83.6, 96.5] µg/L) was assigned the highest posterior inclusion probability for both total and LDL cholesterol. A difference in LDL cholesterol of 8.22 mg/dL (95% CI = 1.85, 14.59) was observed when blood selenium was set to its 75th versus 25th percentile, holding all other metals at their median values. In stratified analyses, the positive association between selenium and LDL cholesterol was only observed among boys or among children exposed to environmental tobacco smoke during childhood.

IMPACT STATEMENT

Growing evidence indicates that cardiovascular events in adulthood are the consequence of the lifelong atherosclerotic process that begins in childhood. Therefore, public health interventions targeting childhood cardiovascular risk factors may have a particularly profound impact on reducing the burden of cardiovascular disease. Although growing evidence supports that both essential and nonessential metals contribute to cardiovascular disease and risk factors, such as dyslipidemia, prior studies have mainly focused on single metal exposures in adult populations. To address this research gap, the current study investigated the joint impacts of multiple metal exposures on lipid concentrations in early childhood.

Nutritional strategies to reduce intestinal cell apoptosis by alleviating oxidative stress

The gut barrier is the first line of defense against harmful substances and pathogens in the intestinal tract. The balance of proliferation and apoptosis of intestinal epithelial cells (IECs) is crucial for maintaining the integrity of the intestinal mucosa and its function. However, oxidative stress and inflammation can cause DNA damage and abnormal apoptosis of the IECs, leading to the disruption of the intestinal epithelial barrier. This, in turn, can directly or indirectly cause various acute and chronic intestinal diseases. In recent years, there has been a growing understanding of the vital role of dietary ingredients in gut health. Studies have shown that certain amino acids, fibers, vitamins, and polyphenols in the diet can protect IECs from excessive apoptosis caused by oxidative stress, and limit intestinal inflammation. This review aims to describe the molecular mechanism of apoptosis and its relationship with intestinal function, and to discuss the modulation of IECs' physiological function, the intestinal epithelial barrier, and gut health by various nutrients. The findings of this review may provide a theoretical basis for the use of nutritional interventions in clinical intestinal disease research and animal production, ultimately leading to improved human and animal intestinal health.

Chromosome-scale assembly of the streamlined picoeukaryote Picochlorum sp. SENEW3 genome reveals Rabl-like chromatin structure and potential for C4 photosynthesis

Genome sequencing and assembly of the photosynthetic picoeukaryotic Picochlorum sp. SENEW3 revealed a compact genome with a reduced gene set, few repetitive sequences, and an organized Rabl-like chromatin structure. Hi-C chromosome conformation capture revealed evidence of possible chromosomal translocations, as well as putative centromere locations. Maintenance of a relatively few selenoproteins, as compared to similarly sized marine picoprasinophytes Mamiellales, and broad halotolerance compared to others in Trebouxiophyceae, suggests evolutionary adaptation to variable salinity environments. Such adaptation may have driven size and genome minimization and have been enabled by the retention of a high number of membrane transporters. Identification of required pathway genes for both CAM and C4 photosynthetic carbon fixation, known to exist in the marine mamiellale pico-prasinophytes and seaweed Ulva, but few other chlorophyte species, further highlights the unique adaptations of this robust alga. This high-quality assembly provides a significant advance in the resources available for genomic investigations of this and other photosynthetic picoeukaryotes.

Protective effects of functional Nano-Selenium supplementation on spleen injury through regulation of p38 MAPK and NF-κB protein expression

Selenium (Se) is a trace element necessary for humans to maintain normal physiological activities, and Se deficiency may lead to splenic injury, while Se supplementation can alleviate splenic injury. However, the mechanism is unclear. In this study, we constructed a Se deficiency animal model by feeding Sprague-Dawley (SD) rats with low Se feed. Meanwhile, we observed the repairing effect of Se supplementation on splenic injury with two doses of novel nano-selenium (Nano-Se) supplement by gavage. We measured the Se content in the spleens of the rats by atomic fluorescence spectroscopy (AFS) method and combined the results of hematoxylin-eosin (HE) and Masson staining to observe the splenic injury, comprehensively evaluating the construction of the animal model of low selenium-induced splenic injury. We measured the mRNA and protein expression levels of p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor kappa-B (NF-κB), and interleukin-6 (IL-6) in the spleen by Real-time quantitative polymerase chain reaction (qPCR), western blot (WB), and immunohistochemistry (IHC). We found that the Se deficiency group exhibited lower Se content, splenic fibrosis, and high expression of p38 MAPK, NF-κB, and IL-6 compared to the normal group. The Se supplement groups exhibited higher Se content, attenuated splenic injury, and down-regulated expression of p38 MAPK, NF-κB, and IL-6 relative to the Se deficiency group. This study suggests that Se deficiency leads to splenic injury in rats, and Se supplementation may attenuate splenic injury by inhibiting the expression of p38 MAPK, NF-κB and IL-6.

The Preventive Effect of Preoperative and Postoperative Selenium on the Medication-Related Osteonecrosis of the Jaw: An Animal Study in Rats

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a condition that can occur primarily in patients undergoing or have previously undergone therapy with bisphosphonates, particularly in the presence of risk factors, such as tooth extraction (TE).

PURPOSE

This study aimed to evaluate the effect of selenium (SEL) administration on the prevention of osteonecrosis of the jaw in an MRONJ animal model.

STUDY DESIGN, SETTING, AND SAMPLE

This study was a longitudinal in vivo animal study using a TE model in a sample of 48 Wistar rats.

PREDICTOR VARIABLE

The predictor variables were SEL exposure, timing of SEL exposure, and zoledronic acid (ZOL) exposure. The animals were randomly assigned to 4 treatment groups (n = 12 per group): 1) saline (negative control), 2) ZOL (positive control), 3) SELpreop + ZOL, and 4) ZOL + SELpostop. The animals were administered saline (negative control) or ZOL (0.06 mg/kg, intraperitoneally) once a week for 5 weeks. All rats underwent TE at the end of the fifth week. SEL (0.3 mg/kg, intraperitoneally) was administered once daily for 15 days to the SELpreop + ZOL group before TE and to the ZOL + SELpostop group after TE. All animals were sacrificed at the end of the ninth week.

MAIN OUTCOME VARIABLES

The primary outcome variables were new bone area, necrotic bone area, fibrosis, new connective tissue formation, and inflammatory cell infiltration in the histopathological analysis, as well as angiogenesis and percentage of osteoblasts in the immunohistochemical analysis.

COVARIATES

There was none.

ANALYSES

Statistical analysis was conducted using the Kruskal-Wallis test, followed by post hoc Bonferroni-corrected Mann-Whitney U tests, with a significance level of P ≤ .05.

RESULTS

The new bone area was higher in the ZOL + SELpostop group (3.00 score) than in the saline group (0.58 ± 1.08 score, P < .001) and the ZOL group (0.82 ± 1.40 score, P = .001), while the necrotic bone area was lower in the ZOL + SELpostop group (0.08 ± 0.29 score) than in the ZOL group (2.82 ± 0.40 score, P < .001) and the SELpreop + ZOL group (1.67 ± 0.89 score, P = .007). The percentage of osteoblasts was higher in the ZOL + SELpostop group (18.73%) than in the saline group (8.63%, P < .001) and the ZOL group (0.07%, P < .001), and it was also higher in the SELpreop + ZOL group (18.49%) than in the ZOL group (0.07%, P < .001).

CONCLUSION AND RELEVANCE

In conclusion SEL prevents MRONJ, with postoperative SEL demonstrating greater prevention effects. Given these findings, we hypothesize that SEL exposure may decrease the risk of MRONJ.

Effect of dietary selenium intake on CVD: a retrospective cohort study based on China Health and Nutrition Survey (CHNS) data

OBJECTIVE

We aimed to examine the association between dietary Se intake and CVD risk in Chinese adults.

DESIGN

This prospective cohort study included adults above 20 years old in the China Health and Nutrition Survey (CHNS), and they were followed up from 1997 to 2015 (n 16 030). Dietary data were retrieved from CHNS, and a 3-d, 24-h recall of food intake was used to assess the cumulative average intake of dietary Se, which was divided into quartiles. The Cox proportional hazards model was adopted to analyse the association between dietary Se intake and incident CVD risk.

SETTING

CHNS (1991, 1993, 1997, 2000, 2004, 2006, 2009, 2011 and 2015).

RESULTS

A total of 663 respondents developed CVD after being followed up for a mean of 9·9 years (median 9 years). The incidence of CVD was 4·3, 3·7, 4·6 and 4·0 per 1000 person-years across the quartiles of cumulative Se intake. After adjusting all potential factors, no significant associations were found between cumulative Se intake and CVD risk. No interactions were found between Se intake and income, urbanisation, sex, region, weight, hypertension and CVD risk.

CONCLUSION

We found no association between dietary Se and CVD.

Dietary supplementation of VA enhances growth, feed utilization, glucose and lipid metabolism, appetite, and antioxidant capacity of Chinese perch (Siniperca chuatsi)

The aim of this study was to investigate the effect of dietary vitamin A on juvenile Chinese perch (Siniperca chuatsi). Chinese perch were fed with five experimental diets containing 0, 20, 40, 60, and 80 mg VA·kg-1 for 8 weeks. Results showed that dietary vitamin A significantly influenced the fish's growth, feed utilization, glucose and lipid metabolism, appetite, and antioxidant capacity. Vitamin A-supplemented groups had higher weight gain rate (WGR) and specific growth rate (SGR) compared to the control group. Feed conversion ratio (FCR) was also lower in the vitamin A-supplemented groups. Dietary vitamin A had no significant effect on the survival rate (SR). Compared to the control group, fish fed with vitamin A had increased feed intake (FI), and the expression of appetite-promoting genes (npy and agrp) was significantly higher in the 40 mg VA·kg-1 group. Vitamin A also enhanced the utilization of dietary protein by Chinese perch. The serum glucose content of the fish fed with 40 mg VA·kg-1 diet was significantly higher than that of the control group and 20 mg VA·kg-1 diet, indicating that the promoting effect of VA on gluconeogenesis was greater than that on glycolysis. Additionally, dietary vitamin A increased the expression of lipid metabolism-related genes (hl and fas) and antioxidant genes (nrf2 and gpx) in the fish. These results suggest that the optimal vitamin A requirement of juvenile Chinese perch bream was estimated to be 37.32 mg VA·kg-1 based on broken-line regression analysis of WGR. In conclusion, this study provides valuable insights into the potential benefits of dietary vitamin A on the growth, metabolism, and antioxidant capacity of Chinese perch.

Novel small-molecule compound YH7 inhibits the biofilm formation of Staphylococcus aureus in a sarX-dependent manner

The emergence of antibiotic-resistant and biofilm-producing Staphylococcus aureus isolates presents major challenges for treating staphylococcal infections. Biofilm inhibition is an important anti-virulence strategy. In this study, a novel maleimide-diselenide hybrid compound (YH7) was synthesized and demonstrated remarkable antimicrobial activity against methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) in both planktonic cultures and biofilms. The minimum inhibitory concentration (MIC) of YH7 for S. aureus isolates was 16 µg/mL. Quantification of biofilms demonstrated that the sub-MIC (4 µg/mL) of YH7 significantly inhibits biofilm formation in both MSSA and MRSA. Confocal laser scanning microscopy analysis further confirmed the biofilm inhibitory potential of YH7. YH7 also significantly suppressed bacterial adherence to A549 cells. Moreover, YH7 treatment significantly inhibited S. aureus colonization in nasal tissue of mice. Preliminary mechanistic studies revealed that YH7 exerted potent biofilm-suppressing effects by inhibiting polysaccharide intercellular adhesin (PIA) synthesis, rather than suppressing bacterial autolysis. Real-time quantitative PCR data indicated that YH7 downregulated biofilm formation-related genes (clfA, fnbA, icaA, and icaD) and the global regulatory gene sarX, which promotes PIA synthesis. The sarX-dependent antibiofilm potential of YH7 was validated by constructing S. aureus NCTC8325 sarX knockout and complementation strains. Importantly, YH7 demonstrated a low potential to induce drug resistance in S. aureus and exhibited non-toxic to rabbit erythrocytes, A549, and BEAS-2B cells at antibacterial concentrations. In vivo toxicity assays conducted on Galleria mellonella further confirmed that YH7 is biocompatible. Overall, YH7 demonstrated potent antibiofilm activity supports its potential as an antimicrobial agent against S. aureus biofilm-related infections. IMPORTANCE Biofilm-associated infections, characterized by antibiotic resistance and persistence, present a formidable challenge in healthcare. Traditional antibacterial agents prove inadequate against biofilms. In this study, the novel compound YH7 demonstrates potent antibiofilm properties by impeding the adhesion and the polysaccharide intercellular adhesin production of Staphylococcus aureus. Notably, its exceptional efficacy against both methicillin-resistant and methicillin-susceptible strains highlights its broad applicability. This study highlights the potential of YH7 as a novel therapeutic agent to address the pressing issue of biofilm-driven infections.

Current Understanding of Human Polymorphism in Selenoprotein Genes: A Review of Its Significance as a Risk Biomarker

Selenium has been proven to influence several biological functions, showing to be an essential micronutrient. The functional studies demonstrated the benefits of a balanced selenium diet and how its deficiency is associated with diverse diseases, especially cancer and viral diseases. Selenium is an antioxidant, protecting the cells from damage, enhancing the immune system response, preventing cardiovascular diseases, and decreasing inflammation. Selenium can be found in its inorganic and organic forms, and its main form in the cells is the selenocysteine incorporated into selenoproteins. Twenty-five selenoproteins are currently known in the human genome: glutathione peroxidases, iodothyronine deiodinases, thioredoxin reductases, selenophosphate synthetase, and other selenoproteins. These proteins lead to the transport of selenium in the tissues, protect against oxidative damage, contribute to the stress of the endoplasmic reticulum, and control inflammation. Due to these functions, there has been growing interest in the influence of polymorphisms in selenoproteins in the last two decades. Selenoproteins' gene polymorphisms may influence protein structure and selenium concentration in plasma and its absorption and even impact the development and progression of certain diseases. This review aims to elucidate the role of selenoproteins and understand how their gene polymorphisms can influence the balance of physiological conditions. In this polymorphism review, we focused on the PubMed database, with only articles published in English between 2003 and 2023. The keywords used were "selenoprotein" and "polymorphism". Articles that did not approach the theme subject were excluded. Selenium and selenoproteins still have a long way to go in molecular studies, and several works demonstrated the importance of their polymorphisms as a risk biomarker for some diseases, especially cardiovascular and thyroid diseases, diabetes, and cancer.

Dietary Selenium Nanoparticles Improved Growth and Health Indices in Asian Seabass (Lates calcarifer) Juveniles Reared in High Saline Water

A 60-day study was carried out to determine the effect of dietary selenium nanoparticles (SeNP) on growth, digestive enzymes, and health status of Asian seabass (Lates calcarifer, 46.5 ± 0.2 g) juveniles reared in high saline water (48 ppt). Five levels of SeNP were added to a basal diet (45% protein, 15% lipid), including control (0), 0.5 (SeNP0.5), 1.0 (SeNP1), 2 (SeNP2), and 4 (SeNP4) mg SeNP kg-1 diet. Fish were stocked into fifteen 2,000 L tanks (50 fish tank-1) filled with 1,800 L sand-filtered seawater (26.5 ± 1.5°C, 48.0 ± 0.2 ppt) in a flow-through system. Each dietary treatment was performed in three replicates. The growth rate positively increased in both linear and quadratic trends with increasing dietary SeNP level (P < 0.05). The liver Se concentration increased with increasing SeNP in diet (P < 0.05). Gut total protease, trypsin, chymotrypsin, alkaline phosphatase (ALP), lipase, and α-amylase activities were significantly enhanced in the SeNP4 group compared to the other treatments (P < 0.05). Antioxidant capacity improved in fish-fed SeNP2 and SeNP4 diets regarding catalase and superoxide dismutase activities and the liver glutathione content. Serum lysozyme and hemolytic activities and white blood cells' respiratory burst activity in the control were lower than in fish-fed SeNP-supplemented diets. Serum total protein, globulin, and globulin/albumin ratio in fish-fed SeNP1, SeNP2, and SeNP4 diets were higher than the other groups (P < 0.05). The interleukin-10 and granulocyte-macrophage colony-stimulating factor genes' relative transcription levels in the gut of fish-fed SeNP4 were higher than the other groups. Serum cholesterol, triglycerides, ALP, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase significantly decreased in fish with increasing SeNP content in the diet. In conclusion, supplementing the diet with 4 mg kg-1, SeNP was recommended to improve growth and health indices in L. calcarifer juveniles reared in high saline water (48 ppt).

The progression of inorganic nanoparticles and natural products for inflammatory bowel disease

There is a growing body of evidence indicating a close association between inflammatory bowel disease (IBD) and disrupted intestinal homeostasis. Excessive production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), along with an increase in M1 proinflammatory macrophage infiltration during the activation of intestinal inflammation, plays a pivotal role in disrupting intestinal homeostasis in IBD. The overabundance of ROS/RNS can cause intestinal tissue damage and the disruption of crucial gut proteins, which ultimately compromises the integrity of the intestinal barrier. The proliferation of M1 macrophages contributes to an exaggerated immune response, further compromising the intestinal immune barrier. Currently, intestinal nanomaterials have gained widespread attention in the context of IBD due to their notable characteristics, including the ability to specifically target regions of interest, clear excess ROS/RNS, and mimic biological enzymes. In this review, we initially elucidated the gut microenvironment in IBD. Subsequently, we delineate therapeutic strategies involving two distinct types of nanomedicine, namely inorganic nanoparticles and natural product nanomaterials. Finally, we present a comprehensive overview of the promising prospects associated with the application of nanomedicine in future clinical settings for the treatment of IBD (graphic abstract). Different classes of nanomedicine are used to treat IBD. This review primarily elucidates the current etiology of inflammatory bowel disease and explores two prominent nanomaterial-based therapeutic approaches. First, it aims to eliminate excessive reactive oxygen species and reactive nitrogen species. Second, they focus on modulating the polarization of inflammatory macrophages and reducing the proportion of pro-inflammatory macrophages. Additionally, this article delves into the treatment of inflammatory bowel disease using inorganic metal nanomaterials and natural product nanomaterials.

Ameliorating Effect of Sodium Selenite on Developmental and Molecular Response of Bovine Cumulus-Oocyte Complexes Matured in Vitro Under Heat Stress Condition

Selenium (Se), an essential trace element, plays an important role in the antioxidative defense mechanism, and it has been proven to improve fertility and reproductive efficiency in dairy cattle. The present study evaluated the potential protective action of Se supplement of in vitro maturation (IVM) media on the maturation and subsequent development of bovine cumulus-oocyte complexes (COCs) exposed to heat stress (HS). The treatment with Se improved the viability of cumulus cells (CCs) and oocytes (P < 0.05). The proportion of oocytes reached metaphase II (MII) and those arrested at metaphase I (MI) was greater and lower in treatment than control respectively (P < 0.05). Supplementation with Se increased the percentage of cleaved embryos, total blastocysts, and blastocyst/cleavage ratio (P < 0.05). Moreover, the upregulation of CCND1, SEPP1, GPX-4, SOD, CAT, and downregulation of GRP78, CHOP, and BAX in both Se-treated CCs and oocytes were recorded. The upregulation of NRF2 was detected in Se-treated CCs other than in oocytes, which showed upregulation of IGF2R and SOX-2 as the markers of quality as well. Se supplement in IVM media improved the viability, maturation, and the level of transcripts related to antioxidant defense and quality of heat-treated oocytes, which coincided with greater subsequent development outcomes. Se ameliorated the viability of CCs along with upregulation of antioxidative candidate gene expression and downregulation of apoptosis-related ones to support their protective role on restoring the quality of oocytes against compromising effects of HS.

A study on the effectiveness of sodium selenite in treating cadmium and perfluoro octane sulfonic (PFOS) poisoned zebrafish (Danio rerio)

Perfluoro octane sulfonate (PFOS) and cadmium (Cd) are toxic elements in the environment. As a micronutrient trace element, selenium (Se) can mitigate the adverse effects induced by PFOS and Cd. However, few studies have examined the correlation between Se, PFOS and Cd in fish. The present study focused on the antagonistic effects of Se on PFOS+Cd-induced accumulation in the liver of zebrafish. The fish was exposed to PFOS (0.08mg/L), Cd (1mg/L), PFOS+ Cd (0.08 mg/L PFOS+1 mg/L Cd), L-Se (0.07mg/L Sodium selenite +0.08mg/L PFOS+1mg/L Cd), M-Se (0.35mg/L Sodium selenite + 0.08mg/L PFOS+ 1 mg/L Cd), H-Se (1.75 mg/L Sodium selenite + 0.08 mg/L PFOS+ 1mg/L Cd) for 14d. The addition of selenium to fish exposed to PFOS and Cd has been found to have significant positive effects. Specifically, selenium treatments can alleviate the adverse effects of PFOS and Cd on fish growth, with a 23.10% improvement observed with the addition of T6 compared to T4. In addition, selenium can alleviate the negative effects of PFOS and Cd on antioxidant enzymes in zebrafish liver, thus reducing the liver toxicity caused by PFOS and Cd. Overall, the supplementation of selenium can reduce the health risks to fish and mitigate the injuries caused by PFOS and Cd in zebrafish.

Biosynthesis, Engineering, and Delivery of Selenoproteins

Selenocysteine (Sec) was discovered as the 21st genetically encoded amino acid. In nature, site-directed incorporation of Sec into proteins requires specialized biosynthesis and recoding machinery that evolved distinctly in bacteria compared to archaea and eukaryotes. Many organisms, including higher plants and most fungi, lack the Sec-decoding trait. We review the discovery of Sec and its role in redox enzymes that are essential to human health and important targets in disease. We highlight recent genetic code expansion efforts to engineer site-directed incorporation of Sec in bacteria and yeast. We also review methods to produce selenoproteins with 21 or more amino acids and approaches to delivering recombinant selenoproteins to mammalian cells as new applications for selenoproteins in synthetic biology.

Selenium deficiency-induced high concentration of reactive oxygen species restricts hypertrophic growth of skeletal muscle in juvenile zebrafish by suppressing TORC1-mediated protein synthesis

Se deficiency causes impaired growth of fish skeletal muscle due to the retarded hypertrophy of muscle fibres. However, the inner mechanisms remain unclear. According to our previous researches, we infer this phenomenon is associated with Se deficiency-induced high concentration of reactive oxygen species (ROS), which could suppress the target of rapamycin complex 1 (TORC1) pathway-mediated protein synthesis by inhibiting protein kinase B (Akt), an upstream protein of TORC1. To test this hypothesis, juvenile zebrafish (45 d post-fertilisation) were fed a basal Se-adequate diet or a basal Se-deficient diet or them supplemented with an antioxidant (DL-α-tocopherol acetate, designed as VE) or a TOR activator (MHY1485) for 30 d. Zebrafish fed Se-deficient diets exhibited a clear Se-deficient status in skeletal muscle, which was not influenced by dietary VE and MHY1485. Se deficiency significantly elevated ROS concentrations, inhibited Akt activity and TORC1 pathway, suppressed protein synthesis in skeletal muscle, and impaired hypertrophy of skeletal muscle fibres. However, these negative effects of Se deficiency were partly (except that on ROS concentration) alleviated by dietary MHY1485 and completely alleviated by dietary VE. These data strongly support our speculation that Se deficiency-induced high concentration of ROS exerts a clear inhibiting effect on TORC1 pathway-mediated protein synthesis by regulating Akt activity, thereby restricting the hypertrophy of skeletal muscle fibres in fish. Our findings provide a mechanistic explanation for Se deficiency-caused retardation of fish skeletal muscle growth, contributing to a better understanding of the nutritional necessity and regulatory mechanisms of Se in fish muscle physiology.

GCLiPP: global crosslinking and protein purification method for constructing high-resolution occupancy maps for RNA binding proteins

GCLiPP is a global RNA interactome capture method that detects RNA-binding protein (RBP) occupancy transcriptome-wide. GCLiPP maps RBP-occupied sites at a higher resolution than phase separation-based techniques. GCLiPP sequence tags correspond with known RBP binding sites and are enriched for sites detected by RBP-specific crosslinking immunoprecipitation (CLIP) for abundant cytosolic RBPs. Comparison of human Jurkat T cells and mouse primary T cells uncovers shared peaks of GCLiPP signal across homologous regions of human and mouse 3' UTRs, including a conserved mRNA-destabilizing cis-regulatory element. GCLiPP signal overlapping with immune-related SNPs uncovers stabilizing cis-regulatory regions in CD5, STAT6, and IKZF1.

The effect of selenium supplementation on disease activity and immune-inflammatory biomarkers in patients with mild-to-moderate ulcerative colitis: a randomized, double-blind, placebo-controlled clinical trial

PURPOSE

Selenium (Se) supplementation may help reduce inflammation and disease activity in ulcerative colitis (UC) patients. We investigated the therapeutic effects of Se administration in cases with mild-to-moderate active UC.

METHODS

A multicenter, double-blind, randomized clinical trial (RCT) was conducted on 100 cases with active mild-to-moderate UC. The patients were randomly allocated to be given an oral selenomethionine capsule (200 mcg/day, n = 50) or a placebo capsule (n = 50) for 10 weeks. The primary outcome was defined as disease activity via the Simple Clinical Colitis Activity Index (SCCAI), and secondary outcomes were measured at the end of the study.

RESULTS

After 10 weeks, the SCCAI score's mean was reduced in the Se group (P < 0.001). At the end of the intervention, clinical improvement (decline of 3 ≥ score from baseline score) was observed in 19 patients (38%) of the Se group and 3 patients (6%) of the placebo group. The patients with clinical remission (defined as SCCAI ≤ 2) were assigned in the Se group (P = 0.014). The Se group's quality of life and Se serum levels were enhanced at the end of the study (P < 0/001). In the Se group, the mean concentration of interleukin-17 decreased (P < 0/001). However, the levels of interleukin-10 showed no considerable change between the two groups in the 10th week (P = 0.23).

CONCLUSION

Se supplementation as add-on therapy with medical management induced remission and improved the quality of life in patients with active mild-to-moderate UC.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

IRCT20091114002709N51; 2020-04-13.

Memory Recovery Effect of a New Bioactive Innovative Combination in Rats with Experimental Dementia

Alzheimer's disease manifests as a complex pathological condition, with neuroinflammation, oxidative stress and cholinergic dysfunction being a few of the many pathological changes. Due to the complexity of the disease, current therapeutic strategies aim at a multitargeted approach, often relying on a combination of substances with versatile and complementary effects. In the present study, a unique combination of α-lipoic acid, citicoline, extracts of leaves from olive tree and green tea, vitamin D3, selenium and an immune-supporting complex was tested in scopolamine-induced dementia in rats. Using behavioral and biochemical methods, we assessed the effects of the combination on learning and memory, and elucidated the mechanisms of these effects. Our results showed that, compared to its components, the experimental combination was most efficient in improving short- and long-term memory as assessed by the step-through method as well as spatial memory as assessed by T-maze and Barnes maze underlined by decreases in AChE activity (p < 0.05) and LPO (p < 0.001), increases in SOD activity in the cortex (p < 0.05) and increases in catalase (p < 0.05) and GPx (p < 0.01) activities and BDNF (p < 0.001) and pCREB (p < 0.05) levels in the hippocampus. No significant histopathological changes or blood parameter changes were detected, making the experimental combination an effective and safe candidate in a multitargeted treatment of AD.

Sedanolide Activates KEAP1-NRF2 Pathway and Ameliorates Hydrogen Peroxide-Induced Apoptotic Cell Death

Sedanolide is a bioactive compound with anti-inflammatory and antitumor activities. Although it has been recently suggested that sedanolide activates the nuclear factor E2-related factor 2 (NRF2) pathway, there is little research on its effects on cellular resistance to oxidative stress. The objective of the present study was to investigate the function of sedanolide in suppressing hydrogen peroxide (H2O2)-induced oxidative damage and the underlying molecular mechanisms in human hepatoblastoma cell line HepG2 cells. We found that sedanolide activated the antioxidant response element (ARE)-dependent transcription mediated by the nuclear translocation of NRF2. Pathway enrichment analysis of RNA sequencing data revealed that sedanolide upregulated the transcription of antioxidant enzymes involved in the NRF2 pathway and glutathione metabolism. Then, we further investigated whether sedanolide exerts cytoprotective effects against H2O2-induced cell death. We showed that sedanolide significantly attenuated cytosolic and mitochondrial reactive oxygen species (ROS) generation induced by exposure to H2O2. Furthermore, we demonstrated that pretreatment with sedanolide conferred a significant cytoprotective effect against H2O2-induced cell death probably due to preventing the decrease in the mitochondrial membrane potential and the increase in caspase-3/7 activity. Our study demonstrated that sedanolide enhanced cellular resistance to oxidative damage via the activation of the Kelch-like ECH-associated protein 1 (KEAP1)-NRF2 pathway.

Biogenic Selenium Nanoparticles Synthesized with Alginate Oligosaccharides Alleviate Heat Stress-Induced Oxidative Damage to Organs in Broilers through Activating Nrf2-Mediated Anti-Oxidation and Anti-Ferroptosis Pathways

Selenium (Se) is an essential trace element for maintaining health due to its ideal antioxidant properties. We previously prepared a new type of biogenic selenium nanoparticles based on alginate oligosaccharides (SeNPs-AOS), and this study aimed to investigate the protective effects of SeNPs-AOS (Se particle size = 80 nm, Se content = 8%) on organ health in broilers challenged with HS. A total of 192 21-day-old Arbor Acres broilers were randomly divided into four groups according to a 2 × 2 experimental design, including a thermoneutral zone group (TN, raised under 23 ± 1.5 °C); TN + SeNPs-AOS group (TN group supplemented 5 mg/kg SeNPS-AOS); HS group (HS, raised under 33 ± 2 °C for 10 h/day); and HS + SeNPs-AOS group (HS group supplemented 5 mg/kg SeNPS-AOS). There were six replicates in each group (eight broilers per replicate). The results showed that SeNPs-AOS improved the splenic histomorphology, enhanced the activity of catalase (CAT) and glutathione peroxidase (GSH-Px) of the spleen, as well as upregulating the splenic mRNA expression of antioxidant-related genes in broilers under HS. In addition, SeNPs-AOS reversed the pathological changes in bursa caused by HS increased the activity of GST, GSH-Px, and CAT and upregulated the mRNA expression of Nrf2 and antioxidant-related genes in the bursa of heat-stressed broilers. In addition, dietary SeNPs-AOS improved the hepatic damage, increased the activity of GSH-Px in the liver, and upregulated the mRNA expression of antioxidant-related genes while downregulating the Keap1 gene expression of the liver in broilers during HS. Moreover, dietary SeNPs-AOS upregulated the anti-ferroptosis-related genes expression of liver in broilers under HS. In conclusion, dietary SeNPs-AOS could relieve HS-induced oxidative damage to the spleen, bursa of Fabricius and liver in broilers by upregulating the Nrf2-mediated antioxidant gene expression and SeNPs-AOS could also upregulate the expression of hepatic Nrf2-related anti-ferroptosis genes in heat-stressed broilers. These findings are beneficial for the development of new nano-antioxidants in broilers.

Selenium Deficiency via the ROS/NLRP3/IL-1β Signaling Pathway Leads to Pyroptosis Injury in Pig Spleen

The aim of the present study was to investigate the effect of selenium (Se) deficiency on the relationship between the pyroptosis and MAPK signaling pathway in spleen injury. A total of 10 two-month-old Sus scrofa domesticus specimens were allocated to two groups. The control group was fed a basal diet (0.15-mg/kg Se), and the experimental group was fed a 0.03-mg/kg Se-deficient diet for 2 months. The pig-spleen histopathological changes were observed with hematoxylin-eosin staining. Frozen sections were prepared to detect the content of ROS in pig-spleen cells. The oxidation stress related indexes were determined using a spectrophotometer. The levels of pyroptosis- and MAPK signaling pathway-related factors were detected via quantitative real-time polymerase chain reaction (qPCR) and western blotting (WB). The results of sections showed that the lymphocytes decreased in number, the spacing of cells widened, and some cells were necrotic in the spleen tissue of pigs fed a low-selenium diet. The content of ROS, malondialdehyde, nitric oxide, H2O2, and catalase activity in the low-selenium group was significantly higher than that in the control group, and SOD activity was decreased. The protein-ratio-levels of p-Nrf2 to Nrf2 were decreased. The expression levels of nod-like receptor (NLR) family pyrin domain containing 3 (NLRP3), IL-1β, IL-18, ASC, gasdermin D, and caspase-1, the protein-ratio-levels of p-AKT serine/threonine kinase (p-AKT) to AKT, p-extracellular regulated protein kinases (ERK) to ERK, p-P38 MAPK to p-P38, and p-c-Jun N-terminal kinase (p-JNK) to JNK were significantly increased in the Se-deficient group compared with the control group. These results suggested that Se deficiency can induce oxidant stress, which increases pyroptosis- and inflammation-related factors of pig-spleen injury.

"Alphabet" Selenoproteins: Implications in Pathology

Selenoproteins are a group of proteins containing selenium in the form of selenocysteine (Sec, U) as the 21st amino acid coded in the genetic code. Their synthesis depends on dietary selenium uptake and a common set of cofactors. Selenoproteins accomplish diverse roles in the body and cell processes by acting, for example, as antioxidants, modulators of the immune function, and detoxification agents for heavy metals, other xenobiotics, and key compounds in thyroid hormone metabolism. Although the functions of all this protein family are still unknown, several disorders in their structure, activity, or expression have been described by researchers. They concluded that selenium or cofactors deficiency, on the one hand, or the polymorphism in selenoproteins genes and synthesis, on the other hand, are involved in a large variety of pathological conditions, including type 2 diabetes, cardiovascular, muscular, oncological, hepatic, endocrine, immuno-inflammatory, and neurodegenerative diseases. This review focuses on the specific roles of selenoproteins named after letters of the alphabet in medicine, which are less known than the rest, regarding their implications in the pathological processes of several prevalent diseases and disease prevention.

Exploring the potential function of trace elements in human health: a therapeutic perspective

A trace element, known as a minor element, is a chemical element whose concentration is very low. They are divided into essential and non-essential classes. Numerous physiological and metabolic processes in both plants and animals require essential trace elements. These essential trace elements are so directly related to the metabolic and physiologic processes of the organism that either their excess or deficiency can result in severe bodily malfunction or, in the worst situations, death. Elements can be found in nature in various forms and are essential for the body to carry out its varied functions. Trace elements are crucial for biological, chemical, and molecular cell activity. Nutritional deficits can lead to weakened immunity, increased susceptibility to oral and systemic infections, delayed physical and mental development, and lower productivity. Trace element enzymes are involved in many biological and chemical processes. These compounds act as co-factors for a number of enzymes and serve as centers for stabilizing the structures of proteins and enzymes, allowing them to mediate crucial biological processes. Some trace elements control vital biological processes by attaching to molecules on the cell membrane's receptor site or altering the structure of the membrane to prevent specific molecules from entering the cell. Some trace elements are engaged in redox reactions. Trace elements have two purposes. They are required for the regular stability of cellular structures, but when lacking, they might activate alternate routes and induce disorders. Therefore, thoroughly understanding these trace elements is essential for maintaining optimal health and preventing disease.

Role of micronutrients in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an autoimmune intestinal disease that includes ulcerative colitis, Crohn's disease, and indeterminate colitis. Patients with IBD are often at risk for malnutrition, including micronutrient deficiencies, due to dietary restrictions and poor intestinal absorption. Micronutrients, including vitamins and minerals, play an important role in the human body's metabolism and maintenance of tissue functions. This article reviews the role of micronutrients in IBD. Micronutrients can affect the occurrence and progression of IBD by regulating immunity, intestinal flora, oxidative stress, intestinal barrier function, and other aspects. Monitoring and timely supplementation of micronutrients are important to delay progression and improve clinical symptoms in IBD patients.

Incorporation of Selenium Derived from Nanoparticles into Plant Proteins in Vivo

Diets comprising selenium-deficient crops have been linked to immune disorders and cardiomyopathy. Selenium nanoparticles (SeNPs) have emerged as a promising nanoplatform for selenium-biofortified agriculture. However, SeNPs fail to reach field-scale applications due to a poor understanding of the fundamental principles of its behavior. Here, we describe the transport, transformation, and bioavailability of SeNPs through a combination of in vivo and in vitro experiments. We show synthesized amorphous SeNPs, when sprayed onto the leaves of Arabidopsis thaliana, are rapidly biotransformed into selenium(IV), nonspecifically incorporated as selenomethionine (SeMet), and specifically incorporated into two selenium-binding proteins (SBPs). The SBPs identified were linked to stress and reactive oxygen species (mainly H2O2 and O2-) reduction, processes that enhance plant growth and primary root elongation. Selenium is transported both upwards and downwards in the plant when SeNPs are sprayed onto the leaves. With the application of Silwet L-77 (a common agrochemical surfactant), selenium distributed throughout the whole plant including the roots, where pristine SeNPs cannot reach. Our results demonstrate that foliar application of SeNPs promotes plant growth without causing nanomaterial accumulation, offering an efficient way to obtain selenium-fortified agriculture.

Association between serum copper, zinc, and selenium concentrations and depressive symptoms in the US adult population, NHANES (2011-2016)

BACKGROUND

Evidence suggests that alterations in serum trace element concentrations are closely associated with mental illness. However, ​studies on the relationship between serum copper, zinc, and selenium concentrations and depressive symptoms are limited and with controversial results. We aimed to investigate the association between serum concentrations of these trace elements and depressive symptoms in US adults.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) (2011-2016) were used in this cross-sectional study. The Patient Health Questionnaire-9 Items (PHQ-9) was employed to assess depressive symptoms. Multiple logistic regression was performed to determine the relationship between the serum concentrations of copper, zinc, and selenium and depressive symptoms.

RESULTS

A total of 4552 adults were included. Subjects with depressive symptoms had higher serum copper concentrations (123.88 ± 1.87) than those without depressive symptoms (116.99 ± 0.86) (p < 0.001). In Model 2, weighted logistic regression analysis showed that the second (Q2) quartile of zinc concentrations (odds ratio [OR] = 1.534, 95% confident interval [CI]: 1.018 to 2.313) were significantly associated with an increased risk of depressive symptoms. Subgroup analysis revealed that the third (Q3) and fourth (Q4) quartiles of copper concentrations (Q3: OR = 2.699, 95% CI: 1.285 to 5.667; Q4: OR = 2.490, 95% CI: 1.026 to 6.046) were also positively associated with depressive symptoms in obese individuals after controlling for all confounders. However, no significant relationship between serum selenium concentrations and depressive symptoms was observed.

CONCLUSIONS

Obese US adults with high serum copper concentrations, as well as US adults in general with low serum zinc concentrations, were susceptible to depressive symptoms. Nevertheless, the causal mechanisms underlying these relationships need to be further explored.

Healthy Diet and Lifestyle Improve the Gut Microbiota and Help Combat Fungal Infection

Western diets are rapidly spreading due to globalization, causing an increase in obesity and diseases of civilization. These Western diets are associated with changes in the gut microbiota related to intestinal inflammation. This review discusses the adverse effects of Western diets, which are high in fat and sugar and low in vegetable fiber, on the gut microbiota. This leads to gut dysbiosis and overgrowth of Candida albicans, which is a major cause of fungal infection worldwide. In addition to an unhealthy Western diet, other factors related to disease development and gut dysbiosis include smoking, excessive alcohol consumption, lack of physical activity, prolonged use of antibiotics, and chronic psychological stress. This review suggests that a diversified diet containing vegetable fiber, omega-3 polyunsaturated fatty acids, vitamins D and E, as well as micronutrients associated with probiotic or prebiotic supplements can improve the biodiversity of the microbiota, lead to short-chain fatty acid production, and reduce the abundance of fungal species in the gut. The review also discusses a variety of foods and plants that are effective against fungal overgrowth and gut dysbiosis in traditional medicine. Overall, healthy diets and lifestyle factors contribute to human well-being and increase the biodiversity of the gut microbiota, which positively modulates the brain and central nervous system.

Blood selenium level can alleviate the nephrotoxicity of lead and cadmium in the general population of the United States: a retrospective cross section analysis of population-based nationally representative data

The current understanding of the interplay between blood selenium, cadmium and lead levels, and chronic kidney disease (CKD) is limited. Our objective was to investigate whether elevated blood selenium levels can mitigate the nephrotoxic effects of lead and cadmium. The exposure variables examined in this study include blood selenium, cadmium, and lead levels measured by ICP-MS. The outcome of interest was CKD, defined as an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m². In total, 10630 participants (mean (SD) age:48.9 ± 18.4; 48.3% male) were included in this analysis. The median (IQR) of blood selenium, cadmium, and lead levels was 191 (177-207) μg/L, 0.300 (0.180-0.540) μg/L, and 0.940 (0.570-1.510) μg/dL, respectively. We observed a significant positive association between cadmium and lead levels and CKD (OR; 1.86; 95%CI: 1.31- 2.64; OR:2.23; 95%CI:1.54-3.24). However, selenium had a negative association with CKD (OR:0.096; 95%CI:0.020-0.457). Based on a reference group with a selenium concentration of ≤ 191 μg/L and cadmium level of > 0.300 μg/L, a significant protective factor in the CKD was seen in subjects with high plasma selenium and lower cadmium concentrations (OR:0.685; 95%CI:0.515-0.912). Then selenium concentration of ≤ 191 μg/L and lead level of > 0.940 μg/dL were set as a reference group, and the OR for CKD decreased among the other group (OR:0.564; 95%CI;0.417- 0.762). The subgroup analysis indicated that there were no effect modifiers. Blood selenium has the potential to mitigate the nephrotoxic effects of lead and cadmium in the general population of the United States.

T-2 toxin metabolism and its hepatotoxicity: New insights on the molecular mechanism and detoxification

T-2 toxin, a type A trichothecene, is a secondary metabolite produced by Fusarium poae, Fusarium sporotrichioides, and Fusarium tricinctum. As the most toxic trichothecenes, T-2 toxin causes severe damage to multiple organs, especially to liver. However, the contamination of T-2 toxin covers a wide range of plants, including nuts, grains, fruits and herbs globally. And due to chemical stability of T-2 toxin, it is difficult to be completely removed from the food and feeds, which poses a great threat to human and animal health. Liver is the major detoxifying organ which also makes it the main target of T-2 toxin. After being absorbed by intestine, the first pass effect will reduce the level of T-2 toxin in blood indicating that liver is the main metabolic site of T-2 toxin in vivo. In this review, updated researches on the hepatotoxicity of T-2 toxin were summarized. The metabolic characteristic of T-2 toxin in vivo was introduced. The main hepatotoxic mechanisms of T-2 toxin are oxidative stress, mitochondrial damage, deoxyribonucleic acid (DNA) methylation, autophagy and apoptosis. Recent research of the main hepatotoxic mechanisms of T-2 toxin and the interactions between these mechanisms were summarized. The remission of the hepatotoxicity induced by T-2 toxin was also studied in this review followed by new findings on the detoxification of hepatotoxicity induced by T-2 toxin. The review aimed to offer a comprehensive view and proposes new perspectives in the field of hepatotoxicity induced by T-2 toxin.

Uncovering the Relationship between Selenium Status, Age, Health, and Dietary Habits: Insights from a Large Population Study including Nonagenarian Offspring from the MARK-AGE Project

An inadequate selenium (Se) status can accelerate the aging process, increasing the vulnerability to age-related diseases. The study aimed to investigate plasma Se and Se species in a large population, including 2200 older adults from the general population (RASIG), 514 nonagenarian offspring (GO), and 293 GO Spouses (SGO). Plasma Se levels in women exhibit an inverted U-shaped pattern, increasing with age until the post-menopausal period and then declining. Conversely, men exhibit a linear decline in plasma Se levels with age. Subjects from Finland had the highest plasma Se values, while those from Poland had the lowest ones. Plasma Se was influenced by fish and vitamin consumption, but there were no significant differences between RASIG, GO, and SGO. Plasma Se was positively associated with albumin, HDL, total cholesterol, fibrinogen, and triglycerides and negatively associated with homocysteine. Fractionation analysis showed that Se distribution among plasma selenoproteins is affected by age, glucometabolic and inflammatory factors, and being GO or SGO. These findings show that sex-specific, nutritional, and inflammatory factors play a crucial role in the regulation of Se plasma levels throughout the aging process and that the shared environment of GO and SGO plays a role in their distinctive Se fractionation.

Selenium suppressed the LPS-induced inflammation of bovine endometrial epithelial cells through NF-κB and MAPK pathways under high cortisol background

The bovine uterus is susceptible to infection, and the elevated cortisol level due to stress are common in cows after delivery. The essential trace element selenium plays a pivotal role in the antioxidant and anti-inflammatory defence system of body. This study investigated whether selenium supplementation protected endometrial cells from inflammation in the presence of high-level cortisol. The primary bovine endometrial epithelial cells were subjected to Escherichia coli lipopolysaccharide to establish cellular inflammation model. The gene expression of inflammatory mediators and proinflammatory cytokines was measured by quantitative PCR. The key proteins of NF-κB and MAPK signalling pathways were detected by Western blot and immunofluorescence. The result showed that pre-treatment of Na2 SeO3 (1, 2 and 4 μΜ) decreased the mRNA expression of proinflammatory genes, inhibited the activation of NF-κB and suppressed the phosphorylation of extracellular signal-regulated kinase, P38MAPK and c-Jun N-terminal kinase. This inhibition of inflammation was more apparent in the presence of high-level cortisol (30 ng/mL). These results indicated that selenium has an anti-inflammatory effect, which is mediated via NF-κB and MAPK signalling pathways and is augmented by cortisol in bovine endometrial epithelial cells.

Associations of selenium exposure with blood lipids: Exploring mediating DNA methylation sites in general Chinese urban non-smokers

Selenium (Se) is widely distributed in the total environment and people are commonly exposed to Se, while the potential effects and mechanisms of Se exposure on blood lipids have not been well established. This study aimed to assess the associations of urinary Se (SeU) with blood lipids and explore the potential mediating DNA methylation sites. We included 2844 non-smoke participants from the second follow-up (2017-2018) of the Wuhan-Zhuhai cohort (WHZH) in this study. SeU and blood lipids [i.e., total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL)] for all participants were determined. The associations of SeU with blood lipids were analyzed by generalized linear models. Then, we conducted the blood lipids related epigenome-wide association studies (EWAS) among 221 never smokers, and the mediation analysis was conducted to explore the potential mediating cytosine-phosphoguanine (CpG) sites in the above associations. In this study, the SeU concentration of the participants in this study was 1.40 (0.94, 2.08) μg/mmol Cr. The SeU was positively associated with TC and LDL, and not associated with TG and HDL. We found 131, 3, and 1 new CpG sites related to TC, HDL, and LDL, respectively. Mediation analyses found that the methylation of cg06964030 (within MIR1306) and cg15824094 (within PLCH2) significantly mediated the positive association between SeU and TC. In conclusion, high levels of Se exposure were associated with increased TC and LDL among non-smokers, and the methylation of MIR1306 and PLCH2 partly mediated Se-associated TC increase. These findings provide new insights into the effects and mechanisms of Se exposure on lipids metabolism and highlight the importance of controlling Se exposure and intake for preventing high blood lipids.

Selenoprotein W Ameliorates Experimental Colitis and Promotes Intestinal Epithelial Repair

Selenoprotein W (Selenow) is a ~9 kDa selenoprotein suggested to play a beneficial role in resolving inflammation. However, the underlying mechanisms are poorly understood. SELENOW expression in the human GI tract using ScRNAseq Gut Cell Atlas and Gene Expression Omnibus (GEO) databases revealed its expression in the small intestine and colonic epithelial, endothelial, mesenchymal, and stem cells and correlated with a protective effect in ulcerative colitis patients. Selenow KO mice treated with 4% dextran sodium sulfate (DSS) showed exacerbated acute colitis, with greater weight loss, shorter colons, and increased fecal occult blood compared to the WT counterparts. Selenow KO mice expressed higher colonic Tnfα, increased Tnfα+ macrophages in the colonic lamina propria, and exhibited loss in epithelial barrier integrity and decreased zonula occludens 1 (Zo-1) expression following DSS treatment. Expression of epithelial cellular adhesion marker (EpCam), yes-associated protein 1 (Yap1), and epidermal growth factor receptor (Egfr) were decreased along with CD24lo cycling epithelial cells in Selenow KO mice. Colonic lysates and organoids confirmed a crosstalk between Egfr and Yap1 that was regulated by Selenow. Overall, our findings suggest Selenow expression is key for efficient resolution of inflammation in experimental colitis that is mediated through the regulation of Egfr and Yap1.

Protective effect of Hovenia dulcis Thunb. leaf extracts against ethanol-induced DNA damage in SH-SY5Y cells

ETHNOPHARMACOLOGICAL RELEVANCE

Hovenia dulcis Thunb. has been used as a medicinal herb for the treatment of hepatic diseases and alcohol intoxication.

AIM OF THE STUDY

The genotoxic effect and the antigenotoxic potential of ethanolic extract of H. dulcis leaves and its methanolic fraction were evaluated against ethanol-induced damages in SH-SY5Y cells.

MATERIALS AND METHODS

The phytochemical analysis and antioxidant activity of H. dulcis extracts were also assessed. In addition, a systems biology analysis was performed to investigate the molecular pathway of action of the H. dulcis leaves compounds.

RESULTS

The ethanolic extract and its methanolic fraction presented genotoxicity through comet assay at 0.5 and 0.25 mg/mL. On the other hand, both extracts showed protective action against ethanol at all concentrations. Additionally, an NBT assay was performed and demonstrated an ability of the extracts to reduce superoxide anion formation when SH-SY5Y cells were challenged with ethanol. HPLC analysis indicated the presence of quercitrin, isoquercitrin, and rutin. Further, system biology assays indicated a molecular action pathway, where the compounds from the leaves of H. dulcis, in addition to performing free radical scavenging activity, activate PP2A, and may inhibit the apoptosis pathway activated by ethanol-induced oxidative stress.

CONCLUSIONS

This work is important to indicate potential antigenotoxic and antioxidant properties of H. dulcis leaves, and its use can be investigated against DNA damage induced by ethanol.

Exiguobacterium sp. as a bioinoculant for plant-growth promotion and Selenium biofortification strategies in horticultural plants

Plant growth-promoting rhizobacteria (PGPR) have a positive effect on plant development and being a promising way to enhance crop productivity and as substitution of chemical fertilizers. Selenium (Se) is an important trace element and its intake is usually lower than the daily minimum amount required for humans; hence, there is a demand on the design of Se biofortification strategies. Here, the genetic traits known to be associated with Plant-Growth Promotion (PGP) and Se biotransformation of Exiguobacterium sp. S17 were evaluated through genome analysis. Its growth-promoting capacity was tested through plant-growth promotion assays in laboratory and field conditions, using Brassica juncea (indian mustard), Beta vulgaris (chard), and Lactuca sativa (lettuce). Additionally, the Se biotransformation ability of Exiguobacterium sp. S17 was evaluated and the obtained selenized bacteria were tested in mustard plants. The sequenced bacteria genome revealed the presence of multiple genes involved in important functions regarding soil and plant colonization, PGP and Se biotransformation. Moreover, it was demonstrated that Exiguobacterium sp. S17 enhanced plant growth and could be useful to produce Se accumulation and biofortification in accumulator plants such as mustard. Thereby, Exiguobacterium sp. S17 might be used for developing new, sustainable, and environmentally friendly agro-technological strategies.

Introduction of Methyl Group in Substituted Isoselenazolones: Catalytic and Mechanistic Study

Copper-catalyzed direct selenation of substituted 2-bromo-N-phenylbenzamide substrates with elemental selenium powder provided a series of methoxy-substituted isoselenazolones via the C-Se and Se-N bond formations. Phenolic substituted isoselenazolones have been obtained by O-demethylation of the corresponding methoxy-substituted analogues using boron tribromide. Some isoselenazolones have been structurally characterized by X-ray single-crystal analysis. The glutathione peroxidase (GPx)-like antioxidant activity of isoselenazolones has been evaluated both in thiophenol and coupled-reductase assays. All isoselenazolones showed good GPx-like activities in the coupled-reductase assay. The ferric-reducing antioxidant power of phenolic antioxidants has also been evaluated. The best phenolic antioxidants were found to be good ferric-reducing antioxidant power agents. The single electron transfer, hydrogen atom transfer, and proton-coupled electron transfer mechanisms for the antioxidant properties of all catalysts have been supported by density functional theory calculations. The catalytic cycle was proposed for one of the phenolic isoselenazolones involving diselenide, selenenyl sulfide, selenol, and selenenic acid as intermediates using ⁷⁷Se{¹H} NMR spectroscopy.

Natural Sources of Selenium as Functional Food Products for Chemoprevention

Cancer is one of the leading causes of death worldwide, the incidence of which is increasing annually. Interest has recently grown in the anti-cancer effect of functional foods rich in selenium (Se). Although clinical studies are inconclusive and anti-cancer mechanisms of Se are not fully understood, daily doses of 100–200 µg of Se may inhibit genetic damage and the development of cancer in humans. The anti-cancer effects of this trace element are associated with high doses of Se supplements. The beneficial anti-cancer properties of Se and the difficulty in meeting the daily requirements for this micronutrient in some populations make it worth considering the use of functional foods enriched in Se. This review evaluated studies on the anti-cancer activity of the most used functional products rich in Se on the European market.

Selenium, Stroke, and Infection: A Threefold Relationship; Where Do We Stand and Where Do We Go?

Stroke is currently the second most common cause of death worldwide and a major cause of serious long-term morbidity. Selenium is a trace element with pleotropic effects on human health. Selenium deficiency has been associated with a prothrombotic state and poor immune response, particularly during infection. Our aim was to synthesize current evidence on the tripartite interrelationship between selenium levels, stroke, and infection. Although evidence is contradictory, most studies support the association between lower serum selenium levels and stroke risk and outcomes. Conversely, limited evidence on the role of selenium supplementation in stroke indicates a potentially beneficial effect of selenium. Notably, the relationship between stroke risk and selenium levels is bimodal rather than linear, with higher levels of serum selenium linked to disturbances of glucose metabolism and high blood pressure, morbidities which are, in turn, substrates for stroke. Another such substrate is an infection, albeit forming a bidirectional relationship with both stroke and the consequences of impaired selenium metabolism. Perturbed selenium homeostasis leads to impaired immune fitness and antioxidant capacity, which both favor infection and inflammation; specific pathogens may also contend with the host for transcriptional control of the selenoproteome, adding a feed-forward loop to this described process. Broader consequences of infection such as endothelial dysfunction, hypercoagulation, and emergent cardiac dysfunction both provide stroke substrates and further feed-forward feedback to the consequences of deficient selenium metabolism. In this review, we provide a synthesis and interpretation of these outlined complex interrelationships that link selenium, stroke, and infection and attempt to decipher their potential impact on human health and disease. Selenium and the unique properties of its proteome could provide both biomarkers and treatment options in patients with stroke, infection, or both.

Selenium, selenoproteins and cancer of the thyroid

Selenium is an essential mineral element with important biological functions for the whole body through incorporation into selenoproteins. This element is highly concentrated in the thyroid gland. Selenoproteins provide antioxidant protection for this tissue against the oxidative stress caused by free radicals and contribute, via iodothyronine deiodinases, to the metabolism of thyroid hormones. It is known that oxidative stress plays a major role in carcinogenesis and that in recent decades there has been an increase in the incidence of thyroid cancer. The anti-carcinogenic action of selenium, although not fully understood, is mainly attributable to selenoproteins antioxidant properties, and to the ability to modulate cell proliferation (cell cycle and apoptosis), energy metabolism, and cellular immune response, significantly altered during tumorigenesis. Researchers have suggested that different forms of selenium supplementation may be beneficial in the prevention and treatment of thyroid cancer; however, the studies have several methodological limitations. This review is a summary of the current knowledge on how selenium and selenoproteins related to thyroid cancer.

Antioxidant activity of the thioredoxin system

The thioredoxin system is composed of thioredoxin (Trx), thioredoxin reductase (TR) and reduced nicotinamide adenine dinucleotide phosphate. Trx is an important antioxidant molecule that can resist cell death caused by various stresses and plays a prominent role in redox reactions. TR is a protein that contains selenium (selenocysteine), in three main forms, namely, TR1, TR2 and TR3. TR1, TR2 and TR3 are mainly distributed in the cytoplasm, mitochondria, and testes, respectively. TR can regulate cell growth and apoptosis. After a cell becomes cancerous, the expression of TR is increased to promote cell growth and metastasis. The Trx system is closely related to neurodegenerative diseases, parasitic infections, acquired immunodeficiency syndrome, rheumatoid arthritis, hypertension, myocarditis, and so on. In addition, the Trx system can remove the reactive oxygen species in the body and keep the inside and outside of the cell in a balanced state. In summary, the Trx system is an important target for the drug treatment of many diseases.

Selenium, Iodine and Iron-Essential Trace Elements for Thyroid Hormone Synthesis and Metabolism

The adequate availability and metabolism of three essential trace elements, iodine, selenium and iron, provide the basic requirements for the function and action of the thyroid hormone system in humans, vertebrate animals and their evolutionary precursors. Selenocysteine-containing proteins convey both cellular protection along with H₂O₂-dependent biosynthesis and the deiodinase-mediated (in-)activation of thyroid hormones, which is critical for their receptor-mediated mechanism of cellular action. Disbalances between the thyroidal content of these elements challenge the negative feedback regulation of the hypothalamus-pituitary-thyroid periphery axis, causing or facilitating common diseases related to disturbed thyroid hormone status such as autoimmune thyroid disease and metabolic disorders. Iodide is accumulated by the sodium-iodide-symporter NIS, and oxidized and incorporated into thyroglobulin by the hemoprotein thyroperoxidase, which requires local H₂O₂ as cofactor. The latter is generated by the dual oxidase system organized as 'thyroxisome' at the surface of the apical membrane facing the colloidal lumen of the thyroid follicles. Various selenoproteins expressed in thyrocytes defend the follicular structure and function against life-long exposure to H₂O₂ and reactive oxygen species derived therefrom. The pituitary hormone thyrotropin (TSH) stimulates all processes required for thyroid hormone synthesis and secretion and regulates thyrocyte growth, differentiation and function. Worldwide deficiencies of nutritional iodine, selenium and iron supply and the resulting endemic diseases are preventable with educational, societal and political measures.

Biogenic Selenium Nanoparticles in Biomedical Sciences: Properties, Current Trends, Novel Opportunities and Emerging Challenges in Theranostic Nanomedicine

Selenium is an important dietary supplement and an essential trace element incorporated into selenoproteins with growth-modulating properties and cytotoxic mechanisms of action. However, different compounds of selenium usually possess a narrow nutritional or therapeutic window with a low degree of absorption and delicate safety margins, depending on the dose and the chemical form in which they are provided to the organism. Hence, selenium nanoparticles (SeNPs) are emerging as a novel therapeutic and diagnostic platform with decreased toxicity and the capacity to enhance the biological properties of Se-based compounds. Consistent with the exciting possibilities offered by nanotechnology in the diagnosis, treatment, and prevention of diseases, SeNPs are useful tools in current biomedical research with exceptional benefits as potential therapeutics, with enhanced bioavailability, improved targeting, and effectiveness against oxidative stress and inflammation-mediated disorders. In view of the need for developing eco-friendly, inexpensive, simple, and high-throughput biomedical agents that can also ally with theranostic purposes and exhibit negligible side effects, biogenic SeNPs are receiving special attention. The present manuscript aims to be a reference in its kind by providing the readership with a thorough and comprehensive review that emphasizes the current, yet expanding, possibilities offered by biogenic SeNPs in the biomedical field and the promise they hold among selenium-derived products to, eventually, elicit future developments. First, the present review recalls the physiological importance of selenium as an oligo-element and introduces the unique biological, physicochemical, optoelectronic, and catalytic properties of Se nanomaterials. Then, it addresses the significance of nanosizing on pharmacological activity (pharmacokinetics and pharmacodynamics) and cellular interactions of SeNPs. Importantly, it discusses in detail the role of biosynthesized SeNPs as innovative theranostic agents for personalized nanomedicine-based therapies. Finally, this review explores the role of biogenic SeNPs in the ongoing context of the SARS-CoV-2 pandemic and presents key prospects in translational nanomedicine.

Relationship between selenium status, selenoproteins and COVID-19 and other inflammatory diseases: A critical review

The antioxidant effects of selenium as a component of selenoproteins has been thought to modulate host immunity and viral pathogenesis. Accordingly, the association of low dietary selenium status with inflammatory and immunodeficiency has been reported in the literature; however, the causal role of selenium deficiency in chronic inflammatory diseases and viral infection is still undefined. The COVID-19, characterized by acute respiratory syndrome and caused by the novel coronavirus 2, SARS-CoV-2, has infected millions of individuals worldwide since late 2019. The severity and mortality from COVID-19 have been associated with several factor, including age, sex and selenium deficiency. However, available data on selenium status and COVID-19 are limited, and a possible causative role for selenium deficiency in COVID-19 severity has yet to be fully addressed. In this context, we review the relationship between selenium, selenoproteins, COVID-19, immune and inflammatory responses, viral infection, and aging. Regardless of the role of selenium in immune and inflammatory responses, we emphasize that selenium supplementation should be indicated after a selenium deficiency be detected, particularly, in view of the critical role played by selenoproteins in human health. In addition, the levels of selenium should be monitored after the start of supplementation and discontinued as soon as normal levels are reached. Periodic assessment of selenium levels after supplementation is a critical issue to avoid over production of toxic metabolites of selenide because under normal conditions, selenoproteins attain saturated expression levels that limits their potential deleterious metabolic effects.

Antitumor effect of selenium-rich Brazil nuts and selenomethionine dietary supplementation on pre-existing 4T1 mammary tumor growth in mice

Selenium (Se) is an essential micronutrient known to play an important role in the antioxidant system that can potentially influence tumor growth. We aimed to investigate the effects of dietary Se supplementation after detection of 4T1 mammary tumor growth in BALB/c mice. Thirty female mice received subcutaneous inoculation of 4T1 cells. After five days, all animals presenting palpable tumors were randomly assigned to three groups: a control group (Se-control) receiving a diet with adequate Se (0.15 mg/kg) and two other groups that received Se-supplemented diets (1.4 mg/kg of total Se) with either Brazilian nuts (Se-Nuts) or selenomethionine (SeMet). Data were assessed by either One or Two-way ANOVA followed by Tukey's HSD or Bonferroni's post hoc tests, respectively. Both Se-supplemented diets reduced tumor volume from the thirteenth day of feeding compared with the Se-adequate (control) diet (p < 0.05). The SeMet group presented a higher Se blood concentration (p < 0.05) than the Se-control group, with the Se-Nuts group presenting intermediate values. Selenoprotein P gene expression in the liver was higher in the Se-Nuts group than in the Se-control group (p < 0.05), while the SeMet group presented intermediate expression. Dietary Se supplementation, starting after detection of 4T1 palpable lesions, reduced tumor volume in mice.