Selenium supplementation protects against oxidative stress-induced cardiomyocyte cell cycle arrest through activation of PI3K/AKT

The Antioxidant and anti-inflammatory Activity of Selenium and Lecithin Combination Against ethanol-induced Gastric Ulcer in mice via Modulating IGF-1/PTEN/Akt/FoxO3a Signaling

Gastric ulcers are one of the most prevalent gastrointestinal disorders. The current study investigated the antioxidant and anti-inflammatory effects of selenium (Se) and lecithin (Lec) alone and in combination against ethanol-induced gastric ulcers in mice, and their ability to modulate insulin-like growth factor-1 (IGF-1)/ Phosphatase and tensin homologue deleted on chromosome 10 (PTEN)/ Protein kinase B (Akt)/ Forkhead box O3a (FoxO3a) signaling. The mice were divided into normal, ethanol, Se + ethanol, Lec + ethanol, Se + Lec + ethanol, and omeprazole + ethanol groups. Treatment with the selected doses was continued for 14 days before a single dose of absolute ethanol (5 ml/kg body weight) was administered to induce gastric ulcers in mice. The results showed that pretreatment with Se and Lec combination effectively decreased both the macro- and microscopic gastric lesions and increased the protection index compared to the ethanol group. Remarkably, the Se and Lec combination decreased the levels of reactive oxygen species, malondialdehyde, and cytochrome c and increased glutathione, glutathione peroxidase, and thioredoxin reductase activities in gastric tissues. The Se and Lec combination increased prostaglandin E2 and interleukin-10 levels but decreased tumor necrosis factor-α, interleukin-6 and interleukin-1β levels compared to either treatment alone. Interestingly, this combination decreased the expression of IGF-1, p-Akt, and FoxO3a proteins and increased PTEN expression in gastric tissues. The gastric tissues examination by hematoxylin and eosin staining confirmed these results. Therefore, the Se and Lec combination showed superior protective effects against ethanol-induced gastric ulcers in mice, compared to either treatment alone, through antioxidant, and anti-inflammatory activities, in addition to modulating IGF-1/PTEN/Akt/FoxO3a pathway signaling.

Selenomethionine modulates the JAK2 / STAT3 / A20 pathway through oxidative stress to alleviate LPS-induced pyroptosis and inflammation in chicken hearts

Selenium (Se) is involved in many physiopathologic processes in humans and animals and is strongly associated with the development of heart disease. Lipopolysaccharides (LPS) are cell wall components of gram-negative bacteria that are present in large quantities during environmental pollution. To investigate the mechanism of LPS-induced cardiac injury and the efficacy of the therapeutic effect of SeMet on LPS, a chicken model supplemented with selenomethionine (SeMet) and/or LPS treatment, as well as a primary chicken embryo cardiomyocyte model with the combined effect of SeMet / JAK2 inhibitor (INCB018424) and/or LPS were established in this experiment. CCK8 kit, Trypan blue staining, DCFH-DA staining, oxidative stress kits, immunofluorescence staining, LDH kit, real-time fluorescence quantitative PCR, and western blot were used. The results proved that LPS exposure led to ROS explosion, hindered the antioxidant system, promoted the expression of the JAK2 pathway, and increased the expression of genes involved in the pyroptosis pathway, inflammatory factors, and heat shock proteins (HSPs). Upon co-treatment with SeMet and LPS, SeMet reduced LPS-induced pyroptosis and inflammation and restored the expression of HSPs by inhibiting the ROS burst and modulating the antioxidant capacity. Co-treatment with INCB018424 and LPS resulted in inhibited of the JAK2 pathway, attenuating pyroptosis, inflammation, and high expression of HSPs. Thus, LPS induced pyroptosis, inflammation, and changes in HSPs activity by activating of the JAK2 / STAT3 / A20 signaling axis in chicken hearts. Moreover, SeMet has a positive effect on LPS-induced injury. This work further provides a theoretical basis for treating cardiac injury by SeMet.

Selenium Deficiency Causes Iron Death and Inflammatory Injury Through Oxidative Stress in the Mice Gastric Mucosa

Selenium (Se) is a trace element essential for the maintenance of normal physiological functions in living organisms. Oxidative stress is a state in which there is an imbalance between oxidative and antioxidant effects in the body. A deficiency of Se can make the body more inclined to oxidation, which can induce related diseases. The aim of this experimental study was to investigate the mechanisms by which Se deficiency affects the digestive system through oxidation. The results showed that Se deficiency treatment led to a decrease in the levels of GPX4 and antioxidant enzymes and an increase in the levels of ROS, MDA, and lipid peroxide (LPO) in the gastric mucosa. Oxidative stress was activated. Triple stimulation of ROS, Fe2+, and LPO induced iron death. The TLR4/NF-κB signaling pathway was activated, inducing an inflammatory response. The expression of the BCL family and caspase family genes was increased, leading to apoptotic cell death. Meanwhile, the RIP3/MLKL signaling pathway was activated, leading to cell necrosis. Taken together, Se deficiency can induce iron death through oxidative stress. Meanwhile, the production of large amounts of ROS activated the TLR4/NF-κB signaling pathway, leading to apoptosis and necrosis of the gastric mucosa.

Sodium selenite (Na2SeO3) attenuates T-2 toxin-induced iron death in LMH cells through the ROS/PI3K/AKT/Nrf2 pathway

T-2 toxin, is a monotrichous mycotoxin commonly found in animal feed and agricultural products that can damage tissues and organs through oxidative stress. Selenium is a trace element with favorable antioxidant effects. However, it is unclear whether T-2 toxin-induces ferroptosis in LMH cells and whether Na2SeO3 has a protective role in this process. To investigate the process of hepatic injury by T-2 toxin and its antagonistic effect by Na2SeO3, we used 20 ng/mL T-2 toxin as well as 160 nmol/L Na2SeO3 to treat the LMH cells. The results demonstrated that exposure to the T-2 toxin induced iron death by increasing the quantity of ROS, leading to oxidative damage, decreasing the quantities of SOD, GPx, and T-AOC, and increasing the accumulation of MDA and H2O2, which resulted in the accumulation of Fe2+ and the down-regulation of the manifestation of linked genes and proteins including FTH1, Gpx4, NQO-1, and HO-1. After the addition of Na2SeO3, the PI3K/AKT/Nrf2 pathway is activated by regulating the selenoproteins gene level, and the above abnormal changes are reversed. In summary, Na2SeO3 alleviated T-2 toxin-induced iron death via the PI3K/AKT/Nrf2 pathway. These study not only broaden the cytotoxic knowledge regarding T-2 toxin, but also serve as a foundation for the use of Na2SeO3 in daily life.

Molecular Mechanisms of Selenium Mitigating Lead Toxicity in Chickens via Mitochondrial Pathway: Selenoproteins, Oxidative Stress, HSPs, and Apoptosis

Lead (Pb), a hazardous heavy metal, can damage the health of organisms. However, it is not clear whether Pb can damage chicken cerebellums and thalami. Selenium (Se), an essential nutrient for organisms, has a palliative effect on Pb poisoning in chickens. In our experiment, a model of chickens treated with Pb and Se alone and in combination was established to investigate the molecular mechanism of Se alleviating Pb-caused damage in both chicken cerebellums and thalami. Our morphological results indicated that Pb caused apoptotic lesions, such as mitochondrial and nuclear damage. Further, the anti-apoptotic gene Bcl-2 decreased; on the contrary, four pro-apoptotic genes (p53, Bax, Cyt c, and Caspase-3) increased under Pb treatment, meaning that Pb caused apoptosis via the p53-Cyt c-Caspase-3 pathway. Furthermore, we further demonstrated that Pb elevated four HSPs (HSP27, HSP40, HSP70, and HSP90), as well as HSP70 took part in the molecular mechanism of Pb-caused apoptosis. In addition, we found that Pb exposure led to oxidative stress via up-regulating the oxidant H2O2 and down-regulating four antioxidants (CAT, SOD, GST, and GPx). Moreover, Pb decreased three Se-containing factors (Txnrd1, Txnrd2, and Txnrd3), further confirming that Pb caused oxidative stress. Interestingly, Se supplementation reversed the above changes caused by Pb and alleviated Pb-induced oxidative stress and apoptosis. A time dependency was demonstrated for Bcl-2, Bax, and Cyt c in the cerebellums, as well as CAT, GPx, and p53 in the thalami of Pb-exposed chickens. HSP70 in cerebellums and HSP27 in thalami were more sensitive than those in thalami and cerebellums, respectively, under Pb exposure. Pb-induced apoptosis of thalami was more severe than cerebellums. In conclusion, after Pb treatment, Txnrds mediated oxidative stress, oxidative stress up-regulated HSPs, and finally, HSP70 triggered apoptosis. Se supplementation antagonized Pb-induced oxidative stress and apoptosis via the mitochondrial pathway and selenoproteins in chicken cerebellums and thalami. This study provides new information for the mechanism of environmental pollutant poisoning and the detoxification of Se on abiotic stress.

Selenium Protects ARPE-19 and ACBRI 181 Cells against High Glucose-Induced Oxidative Stress

Diabetic retinopathy (DR), a complication of diabetes mellitus (DM), can cause severe visual loss. The retinal pigment epithelium (RPE) plays a crucial role in retinal physiology but is vulnerable to oxidative damage. We investigated the protective effects of selenium (Se) on retinal pigment epithelium (ARPE-19) and primary human retinal microvascular endothelial (ACBRI 181) cells against high glucose (HG)-induced oxidative stress and apoptotic cascade. To achieve this objective, we utilized varying concentrations of D-glucose (ranging from 5 to 80 mM) to induce the HG model. HG-induced oxidative stress in ARPE-19 and ACBRI 181 cells and the apoptotic cascade were evaluated by determining Ca2+ overload, mitochondrial membrane depolarization, caspase-3/-9 activation, intracellular reactive oxygen species (ROS), lipid peroxidation (LP), glutathione (GSH), glutathione peroxidase (GSH-Px), vascular endothelial growth factor (VEGF) and apoptosis levels. A cell viability assay utilizing MTT was conducted to ascertain the optimal concentration of Se to be employed. The quantification of MTT, ROS, VEGF levels, and caspase-3 and -9 activation was accomplished using a plate reader. To quantitatively assess LP and GSH levels, GSH-Px activities were utilized by spectrophotometer and apoptosis, mitochondrial membrane depolarization, and the release of Ca2+ from intracellular stores were evaluated by spectrofluorometer. Our investigation revealed a significant augmentation in oxidative stress induced by HG, leading to cellular damage through modulation of mitochondrial membrane potential, ROS levels, and intracellular Ca2+ release. Incubation with Se resulted in a notable reduction in ROS production induced by HG, as well as a reduction in apoptosis and the activation of caspase-3 and -9. Additionally, Se incubation led to decreased levels of VEGF and LP while concurrently increasing levels of GSH and GSH-Px. The findings from this study strongly suggest that Se exerts a protective effect on ARPE-19 and ACBRI 181 cells against HG-induced oxidative stress and apoptosis. This protective mechanism is partially mediated through the intracellular Ca2+ signaling pathway.

Rutin modified selenium nanoparticles reduces cell oxidative damage induced by H2O2 by activating Nrf2/HO-1 signaling pathway

Oxidative damage of neurons is one of the key pathological markers of Alzheimer's disease (AD), which eventually leads to neuronal apoptosis and loss. Nuclear factor E2-related factor 2 (Nrf2) is a key regulator of antioxidant response and is considered to be an important therapeutic target for neurodegenerative diseases. In this study, the selenated derivative of antioxidant rutin (Se-Rutin) was synthesized with sodium selenate (Na₂SeO₃) as raw material by a simple electrostatic-compound in situ selenium reduction method. The effects of Se-Rutin on H₂O₂ induced oxidative damage in Pheochromocytoma PC12 cells were evaluated by cell viability, apoptosis, reactive oxygen species level and the expression of antioxidant response element (Nrf2). The results showed that H₂O₂ treatment significantly increased the level of apoptosis and reactive oxygen species, while the level of Nrf2 and HO-1 decreased. However, Se-Rutin significantly reduced H₂O₂ induced apoptosis and cytotoxicity, and increased the expression of Nrf2 and HO-1, both of which were better than that of pure rutin. Therefore, the activation of Nrf2/HO-1 signaling pathway may be the basis of Se-Rutin's anti-oxidative damage to AD.

Metal-Binding Proteins Cross-Linking with Endoplasmic Reticulum Stress in Cardiovascular Diseases

The endoplasmic reticulum (ER), an essential organelle in eukaryotic cells, is widely distributed in myocardial cells. The ER is where secreted protein synthesis, folding, post-translational modification, and transport are all carried out. It is also where calcium homeostasis, lipid synthesis, and other processes that are crucial for normal biological cell functioning are regulated. We are concerned that ER stress (ERS) is widespread in various damaged cells. To protect cells' function, ERS reduces the accumulation of misfolded proteins by activating the unfolded protein response (UPR) pathway in response to numerous stimulating factors, such as ischemia or hypoxia, metabolic disorders, and inflammation. If these stimulatory factors are not eliminated for a long time, resulting in the persistence of the UPR, it will aggravate cell damage through a series of mechanisms. In the cardiovascular system, it will cause related cardiovascular diseases and seriously endanger human health. Furthermore, there has been a growing number of studies on the antioxidative stress role of metal-binding proteins. We observed that a variety of metal-binding proteins can inhibit ERS and, hence, mitigate myocardial damage.

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.

Deciphering mechanism of Zhishi-Xiebai-Guizhi Decoction against hypoxia/reoxygenation injury in cardiomyocytes by cell metabolomics: Regulation of oxidative stress and energy acquisition

Myocardial ischemia/reperfusion (MI/R) injury is a life-threatening syndrome with high morbidity and mortality. Zhishi-Xiebai-Guizhi Decoction (ZSXBGZD) is a classic traditional Chinese medicine formula, used to treat cardiovascular diseases for centuries. However, its underlying medicinal mechanism has not been clearly elucidated, which hinders its widespread application. Here, the curative effects and therapeutic mechanism of ZSXBGZD against MI/R were addressed based on an integration of pharmaceutical evaluation and cellular metabolomics. First, a hypoxia/reoxygenation (H/R) model in H9c2 cells was employed to resemble MI/R and multiple pharmacological indicators were performed to assess the efficacy of ZSXBGZD. The results showed that ZSXBGZD possessed exceptional ability in attenuating cardiomyocyte injury, concerning oxidative stress, mitochondrial dysfunction, energy acquisition and cell apoptosis. Furthermore, a cell metabolomics approach based on HILIC and UPLC-Q-TOF-MS coupled with multivariate analysis was conducted to explore the metabolic regulation of ZSXBGZD. 38 differential polar metabolites related to H/R were uncovered, and 34 of them were reversed to normal state after the treatment of ZSXBGZD, revealing the perturbations of energy metabolism and amino acid metabolism. Moreover, formula decomposition justified the combination of single herbs to form ZSXBZGD and confirmed the pivotal status of Allii Macrostemonis Bulbus and Trichosanthis Fructus.

Selenium Deficiency Induces Inflammatory Response and Decreased Antimicrobial Peptide Expression in Chicken Jejunum Through Oxidative Stress

Selenium deficiency can affect the level of selenoprotein in organs and tissues and cause inflammation. However, the mechanism of selenium deficiency on jejunal injury in chickens remains unclear. In this study, we established a selenium deficiency model in chickens by feeding a low selenium diet and observed ultrastructural and pathological changes in the jejunum. The expression levels of 25 selenoproteins, the levels of oxidative stress, tight junction (TJ) proteins, and antimicrobial peptides (AMP), as well as the expression levels of factors related to inflammatory signaling pathways, were examined in the intestine and analyzed using principal component analysis (PCA). The results of PCA and quantitative real-time PCR (qRT-PCR) showed that selenium deficiency mainly affected the expression of antioxidant selenoproteins in chicken jejunum, especially glutathione peroxidases, thioredoxin reductase, and iodothyronine deiodinase, thus weakening the antioxidant function in the intestine and inducing oxidative stress. We also found disruption of intestinal TJ structures, a significant reduction in TJ protein expression, and downregulation of antimicrobial peptide levels, suggesting that selenium deficiency led to damage of the intestinal barrier. In addition, a significant increase in inflammatory cell infiltration and expression of inflammatory factors was observed in the jejunum, indicating that selenium deficiency induces inflammatory injury. In conclusion, selenium deficiency downregulates antioxidant selenoproteins levels, induces oxidative stress, decreases intestinal AMP levels, and leads to inflammatory injury and disruption of the intestinal barrier in the jejunum. These results shed new light on the molecular mechanisms of intestinal damage caused by selenium deficiency.

Selenium alleviates heart remodeling through Sirt1/AKT/GSK-3β pathway

Selenium, reported as an important medium for maintaining the body's homeostasis, acts to have multiple bioeffects including anti-inflammatory, anti-oxidant and anti-apoptosis effects. However, its role in heart failure still remains unclear. In this study, we explored the effects of selenium on heart failure and its possible mechanism. The heart failure models were induced by aortic banding and isoproterenol. H&E, TUNEL and PSR staining were performed to detect the degree of cardiomyocyte hypertrophy, apoptosis rates and heart fibrosis, respectively. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect different mRNA levels, and western blot was applied to assess the expressions of relative proteins. Immunofluorescence staining was used to evaluate α-SMA density. We first found that treatment of selenium alleviated heart fibrosis and the development of heart failure but not cardiomyocyte cross sectional areas. Besides, selenium improved heart levels of superoxide dismutase2 (SOD2), glutathione peroxidase (Gpx) and glutathione (GSH) and the activity of SOD, accompanied by decreased apoptosis rate. In addition, our in vitro study has shown that selenium reduced mRNA levels of collagen Ⅰ and collagen III, expressions of a-SMA, p-AKT/AKT and p-GSK-3β/ GSK-3β, apoptosis rates and reactive oxygen species (ROS) levels in H9C2 cardio-myoblasts treated with TGF-β1. Moreover, the level of Sirt1 was found to be up-regulated by selenium which effects were weakened after the administration of small interfering RNA (siRNA)-Sirt1 or EX527 (inhibitor of Sirt1). Our current results have demonstrated that the protective effects of selenium on heart hypertrophy is through the regulation of Sirt1 and AKT/GSK-3β pathway.

Selenium substituted axitinib reduces axitinib side effects and maintains its anti-renal tumor activity

Axitinib is a potent vascular endothelial growth factor receptor (VEGFR) inhibitor, which has a strong inhibitory effect on the three isoforms of VEGFR 1-3. Having strong therapeutic efficacy, its broad use is limited by its side effects such as hypertension, proteinuria, cardiovascular damage, and liver and kidney dysfunction. Selenium compounds are broadly reported to have a good protective effect on cardiovascular disease, inflammation, infection, and immune function. In this study, a selenium substitute of axitinib was synthesized, and its anti-renal cell carcinoma activity and side effects were investigated. The results of the study indicated that Se-axitinib had potent antitumor activity on renal cell carcinoma (RCC), alleviated vascular hyperpermeability, and also alleviated axitinib-related side effects including hypertension, liver dysfunction and kidney dysfunction significantly. Therefore, we suggest that Se-axitinib could be a solution to the severe side effects of VEGFR inhibitors and provide evidence to improve the outcome of RCC treatment.

Identification of critical genes and molecular pathways in COVID-19 myocarditis and constructing gene regulatory networks by bioinformatic analysis

BACKGROUND

There is growing evidence of a strong relationship between COVID-19 and myocarditis. However, there are few bioinformatics-based analyses of critical genes and the mechanisms related to COVID-19 Myocarditis. This study aimed to identify critical genes related to COVID-19 Myocarditis by bioinformatic methods, explore the biological mechanisms and gene regulatory networks, and probe related drugs.

METHODS

The gene expression data of GSE150392 and GSE167028 were obtained from the Gene Expression Omnibus (GEO), including cardiomyocytes derived from human induced pluripotent stem cells infected with SARS-CoV-2 in vitro and GSE150392 from patients with myocarditis infected with SARS-CoV-2 and the GSE167028 gene expression dataset. Differentially expressed genes (DEGs) (adjusted P-Value <0.01 and |Log2 Fold Change| ≥2) in GSE150392 were assessed by NetworkAnalyst 3.0. Meanwhile, significant modular genes in GSE167028 were identified by weighted gene correlation network analysis (WGCNA) and overlapped with DEGs to obtain common genes. Functional enrichment analyses were performed by using the "clusterProfiler" package in the R software, and protein-protein interaction (PPI) networks were constructed on the STRING website (https://cn.string-db.org/). Critical genes were identified by the CytoHubba plugin of Cytoscape by 5 algorithms. Transcription factor-gene (TF-gene) and Transcription factor-microRibonucleic acid (TF-miRNA) coregulatory networks construction were performed by NetworkAnalyst 3.0 and displayed in Cytoscape. Finally, Drug Signatures Database (DSigDB) was used to probe drugs associated with COVID-19 Myocarditis.

RESULTS

Totally 850 DEGs (including 449 up-regulated and 401 down-regulated genes) and 159 significant genes in turquoise modules were identified from GSE150392 and GSE167028, respectively. Functional enrichment analysis indicated that common genes were mainly enriched in biological processes such as cell cycle and ubiquitin-protein hydrolysis. 6 genes (CDK1, KIF20A, PBK, KIF2C, CDC20, UBE2C) were identified as critical genes. TF-gene interactions and TF-miRNA coregulatory network were constructed successfully. A total of 10 drugs, (such as Etoposide, Methotrexate, Troglitazone, etc) were considered as target drugs for COVID-19 Myocarditis.

CONCLUSIONS

Through bioinformatics method analysis, this study provides a new perspective to explore the pathogenesis, gene regulatory networks and provide drug compounds as a reference for COVID-19 Myocarditis. It is worth highlighting that critical genes (CDK1, KIF20A, PBK, KIF2C, CDC20, UBE2C) may be potential biomarkers and treatment targets of COVID-19 Myocarditis for future study.

Antagonistic Interaction of Selenium and Cadmium in Human Hepatic Cells Through Selenoproteins

Cadmium (Cd) is a highly toxic heavy metal for humans and animals, which is associated with acute hepatotoxicity. Selenium (Se) confers protection against Cd-induced toxicity in cells, diminishing the levels of ROS and increasing the activity of antioxidant selenoproteins such as glutathione peroxidase (GPx). The aim of this study was to evaluate the antagonistic effect of selenomethionine (SeMet) against Cd toxicity in HepG2 cells, through the modulation of selenoproteins. To this end, the cells were cultured in the presence of 100 µM SeMet and 5 μM, 15 µM, and 25 µM CdCl₂ and a combination of both species for 24 h. At the end of the experiment, cell viability was determined by MTT assay. The total metal content of Cd and Se was analyzed by triple-quadrupole inductively coupled plasma–mass spectrometry (ICP-QqQ-MS). To quantify the concentration of three selenoproteins [GPx, selenoprotein P (SELENOP), and selenoalbumin (SeAlb)] and selenometabolites, an analytical methodology based on column switching and a species-unspecific isotopic dilution approach using two-dimensional size exclusion and affinity chromatography coupled to ICP-QqQ-MS was applied. The co-exposure of SeMet and Cd in HepG2 cells enhanced the cell viability and diminished the Cd accumulation in cells. Se supplementation increased the levels of selenometabolites, GPx, SELENOP, and SeAlb; however, the presence of Cd resulted in a significant diminution of selenometabolites and SELENOP. These results suggested that SeMet may affect the accumulation of Cd in cells, as well as the suppression of selenoprotein synthesis induced by Cd.

Selenium Attenuates TBHP-Induced Apoptosis of Nucleus Pulposus Cells by Suppressing Mitochondrial Fission through Activating Nuclear Factor Erythroid 2-Related Factor 2

Intervertebral disc (IVD) degeneration (IDD), the leading cause of low back pain (LBP), remains intractable due to a lack of effective therapeutic strategies. Several lines of studies have documented that nucleus pulposus cell (NPC) death induced by excessive oxidative stress is a crucial contributor to IDD. However, the concrete role and regulation mechanisms have not been fully clarified. Selenium (Se), a vital prosthetic group of antioxidant enzymes, is indispensable for maintaining redox homeostasis and promoting cell survival. However, no light was shed on the role of Se on IDD progression, especially regulation on mitochondrial dynamics and homeostasis. To fill this research gap, the current study focuses on the effects of Se, including sodium selenite (SS) and selenomethionine (Se-Met), on IDD progression and the underlying mechanisms. In vitro, we found that both SS and Se-Met alleviated tert-butyl hydroperoxide- (TBHP-) induced oxidative stress, protected mitochondrial function, and inhibited apoptosis of NPCs. Further experiments indicated that Se suppressed TBHP-induced mitochondrial fission and rescued the imbalance of mitochondrial dynamics. Promoting mitochondrial fission by carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) partially counteracted the cytoprotective effects of Se. Moreover, blocking nuclear factor erythroid 2-related factor 2 (Nrf2) with ML385 proved that the effect of Se on regulating mitochondrial dynamics was attributed to the activation of the Nrf2 pathway. In the puncture-induced rat IDD model, a supplement of Se-Met ameliorated degenerative manifestations. Taken together, our results demonstrated that Se suppressed TBHP-induced oxidative stress and mitochondrial fission by activating the Nrf2 pathway, thereby inhibiting the apoptosis of NPCs and ameliorating IDD. Regulation of mitochondrial dynamics by Se may have a potential application value in attenuating the pathological process of IDD.

Selenium Supplementation Improved Cardiac Functions by Suppressing DNMT2-Mediated GPX1 Promoter DNA Methylation in AGE-Induced Heart Failure

Objective

Advanced glycation end products (AGEs) are featured metabolites associated with diabetic cardiomyopathy which is characterized by heart failure caused by myocyte apoptosis. Selenium was proved cardioprotective. This study was aimed at investigating the therapeutic effects and underlying mechanisms of selenium supplementation on AGE-induced heart failure.

Methods

Rats and primary myocytes were exposed to AGEs. Selenium supplementation was administrated. Cardiac functions and myocyte apoptosis were evaluated. Oxidative stress was assessed by total antioxidant capacity (TAC), reactive oxygen species (ROS) generation, and GPX activity. Expression levels of DNA methyltransferases (DNMTs) and glutathione peroxidase 1 (GPX1) were evaluated. DNA methylation of the GPX1 promoter was analyzed.

Results

AGE exposure elevated intracellular ROS generation, induced myocyte apoptosis, and impaired cardiac functions. AGE exposure increased DNMT1 and DNMT2 expression, leading to the reduction of GPX1 expression and activity in the heart. Selenium supplementation decreased DNMT2 expression, recovered GPX1 expression and activity, and alleviated intracellular ROS generation and myocyte apoptosis, resulting in cardiac function recovery. DNA methylation analysis in primary myocytes indicated that selenium supplementation or DNMT inhibitor AZA treatment reduced DNA methylation of the GPX1 gene promoter. Selenium supplementation and AZA administration showed synergic inhibitory effect on GPX1 gene promoter methylation.

Conclusions

Selenium supplementation showed cardioprotective effects on AGE-induced heart failure by suppressing ROS-mediated myocyte apoptosis. Selenium supplementation suppressed ROS generation by increasing GPX1 expression via inhibiting DNMT2-induced GPX1 gene promoter DNA methylation in myocytes exposed to AGEs.

Selenium Alleviates Inflammation in Staphylococcus aureus-Induced Mastitis via MerTK-Dependent Activation of the PI3K/Akt/mTOR Pathway in Mice

Mastitis caused by Staphylococcus aureus infection not only causes serious economic losses, but also affects human health. Se plays an important role in body immunity. However, the mechanisms by which Se regulates mastitis induced by S. aureus are still principally unknown. The purpose of this study is to investigate whether Se can inhibit mastitis induced by S. aureus through regulation of MerTK. Sixty BALB/c female mice were fed low, normal, or high Se concentrations for 7 weeks and then randomly divided into six groups (Se-Low Control group (LSN), Se-Normal Control group (NSN), Se-High Control group (HSN), Se-Low S. aureus group (LSS), Se-Normal S. aureus group (NSS), Se-High S. aureus group (HSS)). The regulation of Se on MerTK was detected via histopathological staining, western blot analysis, enzyme-linked immunosorbent assay, and qRT-PCR. With increased selenium concentrations, the levels of IL-1β, IL-6, and TNF-α decreased, while the phosphorylation levels of MerTK, PI3K, AKT, and mTOR increased. Therefore, this study showed that Se could alleviate S. aureus mastitis by activating MerTK and PI3K/AKT/mTOR pathway.

Selenium Deficiency Causes Inflammatory Injury in the Bursa of Fabricius of Broiler Chickens by Activating the Toll-like Receptor Signaling Pathway

The aim of our study was to observe the effect of selenium (Se) deficiency on inflammatory injury in the bursa of Fabricius of broiler chickens and to determine the role of the Toll-like receptor (TLR)/myeloid differential protein-88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway during this process. Here, we revealed that severe inflammatory injury occurred in the broiler bursa of Fabricius with Se deficiency via histopathology. Moreover, the ultrastructural pathological results showed that the nuclear, mitochondrial, endoplasmic reticulum and cytomembrane structures were damaged to varying degrees. Additionally, interleukin-2 (IL-2), interleukin-6 (IL-6), and interferon (IFN-γ) mRNA expression was markedly upregulated in the broiler bursa of Fabricius with Se deficiency. Furthermore, TLR, toll-interleukin-1 receptor domain-containing adapter-inducing interferon-β (TRIF), MyD88, and NF-κB mRNA expression was also markedly elevated in the broiler bursa of Fabricius with Se deficiency. The above results suggested that Se deficiency increases the expression of numerous proinflammatory cytokines and is probably due to the activation of the TLR/MyD88/NF-κB signaling pathway, which causes inflammatory injury in the bursa of Fabricius of broiler chickens. Our findings provide a theoretical reference for further studying the underlying mechanism of Se deficiency-induced inflammatory injury in the bursa of Fabricius of broiler chickens.

Selenium Deficiency Induces Pathological Cardiac Lipid Metabolic Remodeling and Inflammation

SCOPE

Selenium (Se) disequilibrium is closely involved in many cardiac diseases, although its in vivo mechanism remains uncertain. Therefore, a pig model was created in order to generate a comprehensive picture of cardiac response to dietary Se deficiency.

METHODS AND RESULTS

A total of 24 pigs were divided into two equal groups, which were fed a diet with either 0.007 mg/kg Se or 0.3 mg/kg Se for 16 weeks. Se deficiency caused cardiac oxidative stress by blocking glutathione and thioredoxin systems and increased thioredoxin domain-containing protein S-nitrosylation. Energy production was disordered as free fatty acids were overloaded, the tricarboxylic acid cycle was strengthened, and three respiratory chain proteins enhanced S-nitrosylation. Excess free fatty acids led to increased synthesis of diacylglycerol, phosphatidylcholine, and phosphatidylethanolamine, where the latter two are vulnerable to oxidation and caused an increase in malondialdehyde. Moreover, increased palmitic acid enhanced de novo ceramide synthesis and accumulation. Additionally, Se deficiency initiated inflammation via cytosolic DNA-sensing pathways, which activated downstream interferon regulatory factor 7 and nuclear factor kappa B.

CONCLUSIONS

The present study identified a lipid metabolic vulnerability and inflammation initiation pathways via Se deficiency, which may provide targets for human redox imbalance-induced cardiac disease treatment. This article is protected by copyright. All rights reserved.

A Novel Nano-Antimicrobial Polymer Engineered with Chitosan Nanoparticles and Bioactive Peptides as Promising Food Biopreservative Effective against Foodborne Pathogen E. coli O157-Caused Epithelial Barrier Dysfunction and Inflammatory Responses

For food quality and safety issues, the emergence of foodborne pathogenic bacteria has further accelerated the spread of antibiotic residues and drug resistance genes. To alleviate the harm caused by bacterial infections, it is necessary to seek novel antimicrobial agents as biopreservatives to prevent microbial spoilage. Nanoantimicrobials have been widely used in the direct treatment of bacterial infections. CNMs, formed by chitosan nanoparticles and peptides, are promising antibiotic alternatives for use as excellent new antibacterial drugs against pathogenic bacteria. Herein, the current study evaluated the function of CNMs in the protection of foodborne pathogen Escherichia coli (E. coli) O157 infection using an intestinal epithelial cell model. Antibacterial activity assays indicated that CNMs exerted excellent bactericidal activity against E. coli O157. Assessment of the cytotoxicity risks toward cells demonstrated that 0.0125–0.02% of CNMs did not cause toxicity, but 0.4% of CNMs caused cytotoxicity. Additionally, CNMs did not induced genotoxicity either. CNMs protected against E. coli O157-induced barrier dysfunction by increasing transepithelial electrical resistance, decreasing lactate dehydrogenase and promoting the protein expression of occludin. CNMs were further found to ameliorate inflammation via modulation of tumor factor α, toll-like receptor 4 and nuclear factor κB (NF-κB) expression via inhibition of mitogen-activated protein kinase and NF-κB activation and improved antioxidant activity. Taken together, CNMs could protect the host against E. coli O157-induced intestinal barrier damage and inflammation, showing that CNMs have great advantages and potential application as novel antimicrobial polymers in the food industry as food biopreservatives, bringing new hope for the treatment of bacterial infections.

Integrated Transcriptome Analysis Reveals the Impact of Photodynamic Therapy on Cerebrovascular Endothelial Cells

Blood vessels in the brain tissue form a compact vessel structure and play an essential role in maintaining the homeostasis of the neurovascular system. The low dosage of photodynamic intervention (PDT) significantly affects the expression of cellular biomarkers. To understand the impact of photodynamic interventions on cerebrovascular endothelial cells, we evaluated the dosage-dependent impact of porfimer sodium-mediated PDT on B.END3 cells using flow cytometer, comet assay, RNA sequencing, and bioinformatics analysis. To examine whether PDT can induce disorder of intracellular organelles, we did not observe any significance damage of DNA and cellular skeleton. Moreover, expression levels of cellular transporters-related genes were significantly altered, implying the drawbacks of PDT on cerebrovascular functions. To address the potential molecular mechanisms of these phenotypes, RNA sequencing and bioinformatics analysis were employed to identify critical genes and pathways among these processes. The gene ontology (GO) analysis and protein-protein interaction (PPI) identified 15 hub genes, highly associated with cellular mitosis process (CDK1, CDC20, MCM5, MCM7, MCM4, CCNA2, AURKB, KIF2C, ESPL1, BUB1B) and DNA replication (POLE2, PLOE, CDC45, CDC6). Gene set enrichment analysis (GSEA) reveals that TNF-α/NF-κB and KRAS pathways may play a critical role in regulating expression levels of transporter-related genes. To further perform qRT-PCR assays, we find that TNF-α/NF-κB and KRAS pathways were substantially up-regulated, consistent with GSEA analysis. The current findings suggested that a low dosage of PDT intervention may be detrimental to the homeostasis of blood-brain barrier (BBB) by inducing the inflammatory response and affecting the expression of surface biomarkers.

Nanoparticles Targeting Innate Immune Cells in Tumor Microenvironment

A variety of innate immune cells such as macrophages, dendritic cells, myeloid-derived suppressor cells, natural killer cells, and neutrophils in the tumor microenvironments, contribute to tumor progression. However, while several recent reports have studied the use of immune checkpoint-based cancer immunotherapy, little work has focused on modulating the innate immune cells. This review focuses on the recent studies and challenges of using nanoparticles to target innate immune cells. In particular, we also examine the immunosuppressive properties of certain innate immune cells that limit clinical benefits. Understanding the cross-talk between tumors and innate immune cells could contribute to the development of strategies for manipulating the nanoparticles targeting tumor microenvironments.

Research Progress on Oxidative Stress and Its Nutritional Regulation Strategies in Pigs

Oxidative stress refers to the dramatic increase in the production of free radicals in human and animal bodies or the decrease in the ability to scavenging free radicals, thus breaking the antioxidation-oxidation balance. Various factors can induce oxidative stress in pig production. Oxidative stress has an important effect on pig performance and healthy growth, and has become one of the important factors restricting pig production. Based on the overview of the generation of oxidative stress, its effects on pigs, and signal transduction pathways, this paper discussed the nutritional measures to alleviate oxidative stress in pigs, in order to provide ideas for the nutritional research of anti-oxidative stress in pigs.