Selenium protects against cadmium-induced kidney apoptosis in chickens by activating the PI3K/AKT/Bcl-2 signaling pathway

Transcriptional and biochemical changes in mouse liver following exposure to a metal/drug cocktail. Attenuating effect of a selenium-enriched diet

Real-life pollution usually involves simultaneous co-exposure to different chemicals. Metals and drugs are frequently and abundantly released into the environment, where they interact and bioaccumulate. Few studies analyze potential interactions between metals and pharmaceuticals in these mixtures, although their joint effects cannot be inferred from their individual properties. We have previously demonstrated that the mixture (PC) of the metals Cd and Hg, the metalloid As and the pharmaceuticals diclofenac (DCF) and flumequine (FLQ) impairs hepatic proteostasis. To gain a deeper vision of how PC affects mouse liver homeostasis, we evaluated here the effects of PC exposure upon some biochemical and morphometric parameters, and on the transcriptional profiles of selected group of genes. We found that exposure to PC caused oxidative damage that exceeded the antioxidant capacity of cells. The excessive oxidative stress response resulted in an overabundance of reducing equivalents, which hindered the metabolism and transport of metabolites, including cholesterol and bile acids, between organs. These processes have been linked to metabolic and inflammatory disorders, cancer, and neurodegenerative diseases. Therefore, our findings suggest that unintended exposure to mixtures of environmental pollutants may underlie the etiology of many human diseases. Fortunately, we also found that a diet enriched with selenium mitigated the harmful effects of this combination of toxicants.

Selenium and zinc alleviate hepatotoxicity induced by heavy metal mixture (cadmium, mercury, lead and arsenic) via attenuation of inflammo-oxidant pathways

Heavy metals (HM) are believed to be injurious to humans. Man is exposed to them on daily basis unknowingly, with no acceptable protocol to manage its deleterious effects. These metals occur as mixture of chemicals with varying concentrations in our atmosphere. There are growing calls for the use of essential metals in mitigating the injurious effects induced by heavy metals exposure to man; therefore, the aim of this study was to evaluate the protective effects of essential metals (Zinc and Selenium) in a mixture of heavy metal toxicity. In this study, except for negative controls, all other groups were treated with lead (PbCl2 , 20 mg kg-1 ); cadmium (CdCl2 , 1.61 mg kg-1 ); mercury (HgCl2 , 0.40 mg kg-1 ), and arsenic (NaAsO3, 10 mg kg-1 ) that were formed in distilled water. Pb, Cd, As, and Hg were administered as mixtures to 35, 6 weeks old rats weighing between 80 to 100 g for 60 days. Group I served as normal control without treatment, group II positive control received HM mixture, while groups III to V received HMM with Zn, Se, and Zn + Se respectively. Animal and liver weights, HM accumulation in the liver, food intake (FI), water intake (WI), liver function test, malondialdehyde (MDA), and inflammatory/transcription factor/apoptosis markers were checked. Also, antioxidant enzymes, and histological studies were carried out. Metal mixture accumulated in the liver and caused toxicities which were ameliorated by Zn and Se administration. HM caused significant decrease in FI, WI and distorted the level of liver enzymes, lipid peroxidation, inflammatory markers, antioxidants and architecture of the liver. Co administration with Zn or Se or both reversed the distortions. This study lays credence to the evolving research on the public health implications of low dose metal mixtures and the possible ameliorative properties of Zn and Se.

Stimulation of Autophagy by Dapagliflozin Mitigates Cadmium-Induced Testicular Dysfunction in Rats: The Role of AMPK/mTOR and SIRT1/Nrf2/HO-1 Pathways

Cadmium (Cd) is a widespread environmental pollutant that triggers testicular dysfunction. Dapagliflozin is a selective sodium-glucose co-transporter-2 inhibitor with notable antioxidant and anti-apoptotic features. It has shown marked cardio-, reno-, hepato-, and neuroprotective effects. Yet, its effect on Cd-evoked testicular impairment has not been examined. Hence, the goal of the current study was to investigate the potential positive effect of dapagliflozin against Cd-induced testicular dysfunction in rats, with an emphasis on autophagy, apoptosis, and oxidative insult. Dapagliflozin (1 mg/kg/day) was given by oral gavage, and testicular dysfunction, impaired spermatogenesis, and biomolecular events were studied via immunohistochemistry, histopathology, and ELISA. The current findings demonstrated that dapagliflozin improved relative testicular weight, serum testosterone, and sperm count/motility and reduced sperm abnormalities, signifying mitigation of testicular impairment and spermatogenesis disruption. Moreover, dapagliflozin attenuated Cd-induced histological abnormalities and preserved testicular structure. The testicular function recovery was prompted by stimulating the cytoprotective SIRT1/Nrf2/HO-1 axis, lowering the testicular oxidative changes, and augmenting cellular antioxidants. As regards apoptosis, dapagliflozin counteracted the apoptotic machinery by downregulating the pro-apoptotic signals together with Bcl-2 upregulation. Meanwhile, dapagliflozin reactivated the impaired autophagy, as seen by a lowered accumulation of SQSTM-1/p62 and Beclin 1 upregulation. In the same context, the testicular AMPK/mTOR pathway was stimulated as evidenced by the increased p-AMPK (Ser487)/total AMPK ratio alongside the lowered p-mTOR (Ser2448)/total mTOR ratio. Together, the favorable mitigation of Cd-induced testicular impairment/disrupted spermatogenesis was driven by the antioxidant, anti-apoptotic, and pro-autophagic actions of dapagliflozin. Thus, it could serve as a tool for the management of Cd-evoked testicular dysfunction.

Zinc and selenium attenuate quaternary heavy metal mixture-induced testicular damage via amplification of the antioxidant system, reduction in metal accumulation, inflammatory and apoptotic biomarkers

Heavy metals (HMs) such as cadmium (Cd), lead (Pb), arsenic (As), and mercury (Hg) are highly toxic elements. They are often found together in nature as a heavy metal mixture (HMM) and are known to contribute to subfertility/infertility as environmental pollutants. This study aims to evaluate the potential benefits of treating HMM-induced testicular pathophysiology with zinc (Zn) and/or selenium (Se). Six-week-old male Sprague Dawley rats were grouped into 5 (n = 7). The control group received deionized water, while the other groups were treated with PbCl2 (20 mg kg-1), CdCl2 (1.61 mg kg-1), HgCl2 (0.40 mg kg-1), and Na2AsO3 (10 mg kg-1) in deionized water for 60 days. Additionally, groups III to V received Zn, Se, and Zn/Se, respectively, for 60 days. The study evaluated testis weight, metal accumulation, sperm analysis, FSH, LH, testosterone, prolactin, oxidative stress, antioxidants, pro-inflammatory and apoptotic markers, and presented structural changes in the testis as micrographs. HMM caused a significant increase in testis weight, metal accumulation, prolactin, oxidative stress, and pro-inflammatory and apoptotic markers, while significantly decreasing semen analysis, FSH, LH, and testosterone. Histology showed decreased spermatogenesis and spermiogenesis, as evidenced by the structure of the germ cells and spermatids. However, Zn, Se, or both ameliorated and reversed some of the observed damages. This study provides further evidence for the mitigative potential of Zn, Se, or both in reversing the damage inflicted by HMM in the testis, and as a countermeasure towards improving HM-induced decrease in public health fecundity.

Graphical abstract

Shikonin Alleviates Gentamicin-Induced Renal Injury in Rats by Targeting Renal Endocytosis, SIRT1/Nrf2/HO-1, TLR-4/NF-κB/MAPK, and PI3K/Akt Cascades

Gentamicin causes kidney injury due to its accumulation in proximal tubule epithelial cells via the megalin/cubilin/CLC-5 complex. Recently, shikonin has been shown to have potential anti-inflammatory, antioxidant, antimicrobial, and chloride channel-inhibiting effects. The current study investigated the alleviation of gentamicin-induced renal injury by shikonin while preserving its bactericidal effect. Nine-week-old Wistar rats were administered 6.25, 12.5, and 25 mg/kg/day shikonin orally, one hour after the i.p. injection of 100 mg/kg/day gentamicin for seven days. Shikonin significantly and dose-dependently alleviated gentamicin-induced renal injury, as revealed by restoring normal kidney function and histological architecture. Furthermore, shikonin restored renal endocytic function, as indicated by suppressing the elevated renal megalin, cubilin, and CLC-5 and enhancing the reduced NHE3 levels and mRNA expressions induced by gentamicin. These potentials could be attributed to the modulation of the renal SIRT1/Nrf2/HO-1, TLR-4/NF-κB/MAPK, and PI3K/Akt cascades, which enhanced the renal antioxidant system and suppressed renal inflammation and apoptosis, as indicated by enhancements of SIRT1, Nrf2, HO-1, GSH, SOD, TAC, Iκb-α, Bcl-2, PI3K, and Akt levels and mRNA expressions, with reduction of TLR-4, NF-κB, MAPK, IL-1β, TNF-α, MDA, iNOS, NO, cytochrome c, caspase-3, Bax levels, and Bax/Bcl-2 ratio. Therefore, shikonin is a promising therapeutic agent for alleviating gentamicin-induced renal injury.

Sodium selenite preserves rBM-MSCs' stemness, differentiation potential, and immunophenotype and protects them against oxidative stress via activation of the Nrf2 signaling pathway

BACKGROUND

The physiological level of reactive oxygen species (ROS) is necessary for many cellular functions. However, during the in-vitro manipulations, cells face a high level of ROS, leading to reduced cell quality. Preventing this abnormal ROS level is a challenging task. Hence, here we evaluated the effect of sodium selenite supplementation on the antioxidant potential, stemness capacity, and differentiation of rat-derived Bone Marrow MSCs (rBM-MSCs) and planned to check our hypothesis on the molecular pathways and networks linked to sodium selenite's antioxidant properties.

METHODS

MTT assay was used to assess the rBM-MSCs cells' viability following sodium selenite supplementation (concentrations of: 0.001, 0.01, 0.1, 1, 10 µM). The expression level of OCT-4, NANOG, and SIRT1 was explored using qPCR. The adipocyte differentiation capacity of MSCs was checked after Sodium Selenite treatment. The DCFH-DA assay was used to determine intracellular ROS levels. Sodium selenite-related expression of HIF-1α, GPX, SOD, TrxR, p-AKT, Nrf2, and p38 markers was determined using western blot. Significant findings were investigated by the String tool to picture the probable molecular network.

RESULTS

Media supplemented with 0.1 µM sodium selenite helped to preserve rBM-MSCs multipotency and keep their surface markers presentation; this also reduced the ROS level and improved the rBM-MSCs' antioxidant and stemness capacity. We observed enhanced viability and reduced senescence for rBM-MSCs. Moreover, sodium selenite helped in rBM-MSCs cytoprotection by regulating the expression of HIF-1 of AKT, Nrf2, SOD, GPX, and TrxR markers.

CONCLUSIONS

We showed that sodium selenite could help protect MSCs during in-vitro manipulations, probably via the Nrf2 pathway.

A Mixture of Multi-Strain Probiotics (Lactobacillus Rhamnosus, Lactobacillus Helveticus, and Lactobacillus Casei) had Anti-Inflammatory, Anti-Apoptotic, and Anti-Oxidative Effects in Oxidative Injuries Induced By Cadmium in Small Intestine and Lung

INTRODUCTION

Cadmium (Cd) produces severe oxidative stress, which can result in serious clinical consequences and tissue injury. The aim of the present survey was to investigate the protective effects of native Iranian probiotics (Lactobacillus rhamnosus, L. helveticus, and L. casei) against cadmium (Cd)-induced toxicity against the small intestine and lung at histopathological and biochemical levels.

MATERIALS AND METHODS

Twenty-one adult male Wistar rats were randomized into three groups of seven rats (control, Cd-treated (3 mg/kg), and concomitant Cd and mix probiotic treatment for 30 days). Histological alterations were appraised via hematoxylin & eosin, Trichrome Masson, and PAS staining. The qRT-PCR technique was applied to assess the expression of pro-apoptotic, anti-apoptotic, and pro-inflammatory genes. Antioxidant enzymes activity was measured via ZellBio kits.

RESULTS

Probiotic-treated rats displayed low production of lipid peroxides, reduced malondialdehyde (MDA) level, and elevated contents of superoxide dismutase (SOD) and catalase (CAT) enzymes compared with Cd-treated rats. The results of qRT-PCR demonstrated the up-regulation of Bax, p53, and caspase 3 and down-regulation of Bcl2, TNF-α, and IL-6 genes in both the intestine and lungs of mix probiotic-treated rats compared with Cd-treated animals. Histopathological findings revealed that the probiotic formulation improved Cd-triggered tissue damage in the intestine and lungs.

CONCLUSION

The strong cytoprotective benefits of Iranian probiotics against Cd-induced tissue injury observed in this study may be due to their anti-inflammatory and antioxidant properties. Therefore, additional clinical and experimental research is required to explain the precise mechanisms of probiotics' beneficial impacts and underline their potential therapeutic use.

A Peptide-Conjugated Probe with Cleavage-Induced Morphological Change for Treatment on Tumor Cell Membrane

Despite the promising advancements of in situ forming nanoassembly for the inhibition of tumor growth and metastasis, the lack of sufficient triggering sites and hardly controlling the forming position restrict their further developments. Herein, a smart transformable peptide-conjugated probe (DMFA) with enzyme cleavage-induced morphological change is designed for treatment on the tumor cell membrane. Specifically, after self-assembling into nanoparticles and anchoring on the cell membrane with sufficient interaction sites rapidly and stably, DMFA will be efficiently cleaved into α-helix forming part (DP) and β-sheet forming part (LFA) by overexpressed matrix metalloproteinase-2. Thus, the promoted Ca²⁺ influx by DP-induced cell membrane breakage and decreased Na⁺ /K⁺ -ATPase activity by LFA-assembled nanofibers wrapping the cells can inhibit PI3K-Akt signaling pathway, leading to the inhibition of tumor cell growth and metastasis. This peptide-conjugated probe undergoes in situ morphological transformation on the cell membrane, exhibiting great potential in tumor therapy.

Understanding the mechanistic roles of environmental heavy metal stressors in regulating ferroptosis: adding new paradigms to the links with diseases

Ferroptosis is a new type of iron-dependent cell death induced by a failure of the lipid repair protein GPX4 or the Xc- antiporter, which is essential for glutathione production. Some heavy metals such as arsenic (As), cobalt (Co), cadmium (Cd), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni), mercury (Hg) as well as zinc (Zn) are shown to induce ferroptotic cell death involving the generation of oxidative stress, mitochondrial dysfunctioning, lipid peroxidation, and several other cellular etiologies. However, selenium (Se) treatment has been shown to enhance adaptive transcription responses to protect cells from ferroptosis. Heavy metals like Cadmium exposure activated ALK4/5 signaling via Smad3 and Akt signaling which leads to cell death mechanism. Continuous exposure to a small dose of mercury can damage tissues, and methylmercury bind to sulfhydryl proteins and GSH, this elevates oxidative stress, free radical accumulation, glutathione depletion, mitochondrial damage, and inhibited the nuclear factor-κB pathway which leads to ferroptotic cell death. Animals exposed to nickel and cobalt may have increased lipid peroxidation which can induce ferroptosis. Glutathione depletion is caused by Zn intoxication and exposure to manganese. These metals are systemic toxins that have been shown adverse effects on humans. Ferroptosis has recently been related to several pathological disorders, including, Alzheimer's disease, Parkinson's disease, Huntington's disease, as well as cardiovascular disease, and any type of cancer. For these disorders and some heavy metal toxicity, ferroptosis suppression needs to be looked upon as a promising therapeutic choice.

Topiramate Reprofiling for the Attenuation of Cadmium-Induced Testicular Impairment in Rats: Role of NLRP3 Inflammasome and AMPK/mTOR-Linked Autophagy

Topiramate, a promising drug classically used for the management of neurological disorders including epilepsy and migraine, has demonstrated marked anti-inflammatory and anti-apoptotic actions in murine models of cardiac post-infarction inflammation, wound healing, and gastric/intestinal injury. However, its potential impact on cadmium-induced testicular injury remains to be elucidated. Herein, the present study aimed to explore the effect of topiramate against cadmium-invoked testicular impairment with emphasis on the molecular mechanisms linked to inflammation, apoptosis, and autophagy. Herein, administration of topiramate (50 mg/kg/day, by gavage) continued for 60 days and the testes were examined by histology, immunohistochemistry, and biochemical assays. The present data demonstrated that serum testosterone, sperm count/abnormalities, relative testicular weight, and histopathological aberrations were improved by topiramate administration to cadmium-intoxicated rats. The rescue of testicular dysfunction was driven by multi-pronged mechanisms including suppression of NLRP3/caspase-1/IL-1β cascade, which was evidenced by dampened caspase-1 activity, lowered IL-1β/IL-18 production, and decreased nuclear levels of activated NF-κBp65. Moreover, curbing testicular apoptosis was seen by lowered Bax expression, decreased caspase-3 activity, and upregulation of Bcl-2. In tandem, testicular autophagy was activated as seen by diminished p62 SQSTM1 accumulation alongside Beclin-1 upregulation. Autophagy activation was associated with AMPK/mTOR pathway stimulation demonstrated by decreased mTOR (Ser2448) phosphorylation and increased AMPK (Ser487) phosphorylation. In conclusion, combating inflammation/apoptosis and enhancing autophagic events by topiramate were engaged in ameliorating cadmium-induced testicular impairment.

Protective Effects of Astilbin Against Cadmium-Induced Apoptosis in Chicken Kidneys via Endoplasmic Reticulum Stress Signaling Pathway

Cadmium (Cd) can cause endoplasmic reticulum stress (ERS) and apoptosis in animals. The kidney is an organ seriously affected by Cd because it can accumulate metal ions. Astilbin (ASB) is a dihydroflavonol rhamnoside, which has an anti-renal injury effect. This study aimed to evaluate the protective effect of ASB on Cd-induced ERS and apoptosis in the chicken kidney. In this study, a total of 120 1-day-old chickens were randomly divided into 4 groups. Chickens were fed with a basic diet (Con group), ASB 40 mg/kg (ASB group), CdCl₂ 150 mg/kg + ASB 40 mg/kg (ASB/Cd group), and CdCl₂ 150 mg/kg (Cd group) for 90 days. The results showed that Cd exposure induced pathological and ultrastructural damages and apoptosis in chicken kidneys. Compared with the Con group, metallothionein (MT1/MT2) level, nitric oxide (NO) content, inducible nitric oxide synthase (iNOS) activity, ERS-related genes 78-kDa glucose-regulated protein (Grp78), protein kinase PKR-like endoplasmic reticulum kinase (Perk), activating transcription factor 4 (Atf4) and CAAT/enhancer-binding protein (C/EBP) homologous protein (Chop), and pro-apoptotic gene B-cell lymphoma 2 (Bcl-2)-associated X (Bax), caspase-12, caspase-9, caspase-3 expression levels, and apoptotic rate were significantly increased in the Cd group. The expression level of Bcl-2 was significantly decreased in the Cd group. ASB/Cd combined treatment significantly improves the damage of chicken kidneys by ameliorating Cd-induced kidney ERS and apoptosis. Cd can cause the disorder of the GRP78 signal axis, activate the PERK-ATF4-CHOP pathway, aggravate the structural damage and dysfunction of ER, and promote the apoptosis of chicken kidneys, while the above changes were significantly alleviated in the ASB/Cd group. The results showed that ASB antagonizes the negative effects of Cd and against Cd-induced apoptosis in chicken kidneys via ERS signaling pathway.

The ameliorative effect of kaempferol against CdCl2- mediated renal damage entails activation of Nrf2 and inhibition of NF-kB

This study evaluated the nephroprotective effect of kaempferol against cadmium chloride (CdCl₂) -induced nephropathy in rats. It also investigated if activation of Nrf2 is a common mechanism of action. Adult male rats ((150 ± 15 g) were divided into 4 groups (n = 8/each) as a control (1% DMSO, orally), control + kaempferol (200 mg/kg, orally), CdCl₂ (50 mg/l in drinking water), and CdCl₂ + kaempferol (200 mg/kg)-treated rats. All treatments were conducted for 8 weeks. Kaempferol significantly attenuated CdCl₂-induced weight loss, reduction in kidney weights, and the injury in the glomeruli, proximal tubules, and distal tubules in the treated rats. It also significantly lowered serum levels of urea and creatinine, increased urine output and urinary creatinine levels and clearance but reduced urinary levels of albumin urinary albumin exertion (UAER), and urinary albumin/creatinine ratio (UACR) in these rats. In parallel, kaempferol downregulated renal levels of cleaved caspase-3 and Bax and unregulated those of Bcl2. In the kidney tissues of the control animals and CdCl₂ rats, kaempferol significantly attenuated oxidative stress, inflammation and significantly boosted levels of manganese superoxide dismutase and glutathione. Also, and in both groups, kaempferol suppressed the nuclear levels of NF-κB p65, downregulated Keap1, and stimulated the nuclear activation and protein levels of Nrf2. In conclusion, kaempferol is a potential therapeutic drug to prevent CdCl₂-induced nephropathy due to its anti-inflammatory and anti-oxidant effects mediated by suppressing NF- NF-κB p65 and transactivating Nrf2.

Cadmium induces apoptosis and autophagy in swine small intestine by downregulating the PI3K/Akt pathway

Cadmium (Cd) is an environmental contaminant, which is potentially toxic. It is well known that Cd can accumulate in the liver and kidney and cause serious damage. However, few studies have investigated the mechanism of intestinal damage induced by Cd in swine. Here, we established Cd poisoning models in vivo and in vitro to explore the mechanism of intestinal injury induced by Cd in swine. The morphology of intestinal tissue cells was observed by TUNEL staining and electron microscopy, and the morphology of IPEC-J2 cells was observed by flow cytometry, Hoechst staining, and MDC staining. Cell morphological observations revealed that Cd treatment induced ileal apoptosis and autophagy. The effects of Cd on the PI3K/Akt pathway, as well as on apoptosis and autophagy-related protein expression in intestinal cells, were analyzed by western blot (WB) and the expression of mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The results showed that Cd induced autophagy by increasing the levels of autophagy markers Beclin1, Autophagy-associated gene 5 (ATG5), Autophagy-associated gene 16 (ATG16), and Microtubule-associated protein light chains 3-2 (LC3-II), and by reducing the expression levels of Mechanistic target of rapamycin kinase (mTOR) and Microtubule-associated protein light chains 3-1 (LC3-I). Cell apoptosis was induced by increasing the expression of apoptosis markers Bcl-2 associated X protein (Bax), Cysteinyl aspartate specific proteinase 9 (Caspase9), cleaved Caspase9, Cysteinyl aspartate specific proteinase 3 (Caspase3), and cleaved Caspase3, and by reducing the expression of B cell lymphoma/leukemia 2 (Bcl-2). At the same time, Cd decreased the expression of phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), and their phosphorylation. We treated IPEC-J2 cells with the PI3K activator 740Y-P and analyzed the morphological changes as well as autophagy and apoptosis-related gene expression. The results showed that 740Y-P could reduce apoptosis and autophagy induced by Cd. In conclusion, our findings suggest that Cd induces intestinal apoptosis and autophagy in swine by inactivating the PI3K/Akt signaling pathway.

Multi-Omics Profiling Reveals Se Deficiency-Induced Redox Imbalance, Metabolic Reprogramming, and Inflammation in Pig Muscle

BACKGROUND

Nutritional muscle dystrophy is associated with selenium (Se) deficiency; however, the underlying mechanism remains unclear.

OBJECTIVES

This study aimed to understand the crosstalk among redox status, energy metabolism, and inflammation in nutritional muscle dystrophy induced by dietary Se deficiency.

METHODS

Eighteen castrated male pigs (Yorkshire, 45 d old) were fed Se-deficient (Se-D; 0.007 mg Se/kg) or Se-adequate (Se-A; in the form of selenomethionine, 0.3 mg Se/kg) diets for 16 wk. The muscle Se concentrations; antioxidant capacity; and gene expression, transcriptome, global proteome, metabolome, and lipidome profiles were analyzed. The transcriptome, metabolome, and proteome profiles were analyzed with biostatistics, bioinformatics, and pathway enrichment analysis; other data were analyzed with Student's 2-sided t tests.

RESULTS

The muscle Se content in the Se-D group was 96% lower than that in the Se-A group (P < 0.05). The activity of glutathione peroxidase (GPX) and thioredoxin reductase (TXNRD) in the Se-D group was 42%-69% lower than that in the Se-A group (P < 0.05). The mRNA levels of 10 selenoprotein genes were 25%-84% lower than those in the Se-A group (P < 0.05). Multi-omics analyses indicated that the levels of 1378 transcripts, 83 proteins, 22 metabolites, and 55 lipid molecules were significantly altered in response to Se deficiency. Se deficiency-induced redox imbalance led to muscle central carbon and lipid metabolism reprogramming, which enhanced the glycolysis pathway and decreased phospholipid synthesis. Inflammation and apoptosis were observed in response to Se deficiency-induced muscle oxidative stress, which may have been associated with extracellular matrix (ECM) remodeling, suppressed focal adhesion and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling, and activation of the NF-κB signaling pathway.

CONCLUSIONS

These results contributed to understanding the crosstalk among redox, energy metabolism, and inflammation in Se deficiency-induced muscle dystrophy in pigs, and may provide intervention targets for muscle disease treatment.

Identification of epigenetic modifications mediating the antagonistic effect of selenium against cadmium-induced breast carcinogenesis

The antagonistic effect of selenium (Se) against cadmium (Cd)-induced breast carcinogenesis was reported, but underlying mechanisms were unclear. The aim of this study was to identify the epigenetically regulated genes and biological pathways mediating the antagonistic effect. We exposed MCF-7 cells to Cd and Se alone or simultaneously. Cell proliferation was assessed by MTT assay, and differential epigenome (DNA methylation, microRNA, and long non-coding RNA) was obtained by microarrays. We cross-verified the epigenetic markers with differential transcriptome, and the ones modulated by Cd and Se in opposite directions were regarded to mediate the antagonistic effect. The epigenetically regulated genes were validated by using gene expression data in human breast tissues. We further assessed the biological functions of these validated genes. Our results showed that Se alleviated the proliferative effect of Cd on MCF-7 cell. A total of 10 epigenetically regulated genes were regarded to mediate the antagonistic effect, including APBA2, KIAA0895, DHX35, CPEB3, SVIL, MYLK, ZFYVE28, ABLIM2, GRB10, and PCDH9. Biological function analyses suggested that these epigenetically regulated genes were involved in multiple cancer-related pathways, such as focal adhesion and PI3K/Akt pathway. In conclusion, we provided evidence that Se antagonized the Cd-induced breast carcinogenesis via epigenetic modification and revealed the critical pathways.

The influence of PM2.5 exposure on kidney diseases

The harm of air pollution to public health has become a research hotspot, especially atmospheric fine-particulate matter (PM_2.5). In recent years, epidemiological investigations have confirmed that PM_2.5 is closely related to chronic kidney disease and membranous nephropathy Basic research has demonstrated that PM_2.5 has an impact on the normal function of the kidneys through accumulation in the kidney, endothelial dysfunction, abnormal renin-angiotensin system, and immune complex deposition. Moreover, the mechanism of PM_2.5 damage to the kidney involves inflammation, oxidative stress, apoptosis, DNA damage, and autophagy. In this review, we summarized the latest developments in the effects of PM_2.5 on kidney disease in human and animal studies, so as to provide new ideas for the prevention and treatment of kidney disease.

Protective Effect of Vitamin E on Cadmium-Induced Renal Oxidative Damage and Apoptosis in Rats

Cadmium (Cd), a widely distributed heavy metal, is extremely toxic to the kidney. Vitamin E (VE) is an important antioxidant in the body. It is known that VE exerts a protective effect on renal oxidative damage caused by Cd, but the effect and mechanism of VE on apoptosis are not fully understood. Thus, we conducted this study to explore the protective effect of VE on Cd-induced renal apoptosis and to elucidate its potential mechanism. Thirty-two 9-week-old male Sprague-Dawley rats were randomly divided into four groups, namely control, VE (100 mg/kg VE), Cd (5 mg/kg CdCl₂), and VE + Cd (100 mg/kg VE + 5 mg/kg CdCl₂), and received intragastric administration of Cd and/or VE for 4 weeks. The results showed that Cd exposure significantly reduced the weight of the body and kidney, elevated the accumulation of Cd in the kidney as well as the levels of BUN and Scr in serum, caused renal histological alterations, decreased the GSH and T-AOC contents and antioxidant enzyme (SOD, CAT, GSH-PX) activities, and increased renal MDA content. And the increased number of TUNEL-positive cells by Cd was accompanied by upregulated mRNA and protein expressions of apoptotic regulatory molecules (Bax, Caspase-3, GRP94, GRP78, Caspase-8) and downregulated Bcl-2 expressions. However, the combined treatment of Cd and VE could restore the above parameters to be close to those in the control rats. In conclusion, VE supplement could alleviate Cd-induced rat renal damage and oxidative stress through enhancing the antioxidant defense system and inhibiting apoptosis of renal cells.

Cadmium exposure activates the PI3K/AKT signaling pathway through miRNA-21, induces an increase in M1 polarization of macrophages, and leads to fibrosis of pig liver tissue

Cadmium (Cd) is a toxic substance that pollutes the environment with multiple organs. Long-term exposure to Cd can cause fibrosis in the lungs and other organs of animal body. This article explored the effects of subacute Cd exposure on pig liver fibrosis, as well as the polarization of microRNA (miRNA) and M1/M2 macrophages during this process. Based on the establishment of the pig subacute CdCl2 exposure model, we used immunofluorescence staining, Masson staining, qRT-PCR and western blotting to conduct further research. The results showed that Cd exposure can increase the expression of miRNA-21, decrease the expression of TGF-β and SMAD7, increase the expression of PI3K/AKT signaling pathway, cause the M1/M2 imbalance and the increase of M1 polarization. Meantime, it causes the secretion of inflammatory cytokines (TNF-α, IL-1β, and IL-6), and causes an imbalance in the expression of TIMP1, MMP2, and MMP9, which are related to the degree of fibrosis. And the expression of α-SMA, COL1 and COL3 were up-regulated. In the pig, these results indicate that liver fibrosis caused by subacute CdCl2 exposure is induced by the M1 polarization of macrophages through the PI3K/AKT signaling pathway activated by miRNA-21 signaling pathway. These research results not only enrich the theoretical basis and reference value of Cd toxicology research, but also provide new references and new research ideas for comparative medicine.

Anti-Cancer Properties of Coix Seed Oil against HT-29 Colon Cells through Regulation of the PI3K/AKT Signaling Pathway

This study aims to observe the effects of coix seed oil (CSO) on HT-29 cells and investigate its possible regulation mechanism of the PI3K/Akt signaling pathway. Fatty acid analysis showed that coix seed oil mainly contains oleic acid (50.54%), linoleic acid (33.76%), palmitic acid (11.74%), and stearic acid (2.45%). Fourier transform infrared results found that the fatty acid functional groups present in the oil matched well with the vegetable oil band. The results from CCK-8 assays showed that CSO dose-dependently and time-dependently inhibited the viability of HT-29 cells in vitro. CSO inhibited cell viability, with IC₅₀ values of 5.30 mg/mL for HT-29 obtained after 24 h treatment. Morphological changes were observed by apoptotic body/cell nucleus DNA (Hoechst 33258) staining using inverted and fluorescence microscopy. Moreover, flow cytometry analysis was used to evaluate the cell cycle and cell apoptosis. It showed that CSO induced cell apoptosis and cycle arrest in the G₂ phase. Quantitative real-time PCR and Western blotting revealed that CSO induced cell apoptosis by downregulating the PI3K/AKT signaling pathway. Additionally, CSO can cause apoptosis in cancer cells by activating caspase-3, up-regulating Bax, and down-regulating Bcl-2. In conclusion, the results revealed that CSO induced G₂ arrest and apoptosis of HT-29 cells by regulating the PI3K/AKT signaling pathway.

Aberrant promoter hypermethylation inhibits RGMA expression and contributes to tumor progression in breast cancer

Breast cancer (BC) is the most common cancer in women worldwide, and the exploration of aberrantly expressed genes might clarify tumorigenesis and help uncover new therapeutic strategies for BC. Although RGMA was recently recognized as a tumor suppressor gene, its detailed biological function and regulation in BC remain unclear. Herein, we found that RGMA was downregulated in BC tissues compared with non-tumorous breast tissues, particularly in metastatic BC samples, and that patients with low RGMA expression manifested a poorer prognosis. Furthermore, DNMT1 and DNMT3A were found to be recruited to the RGMA promoter and induced aberrant hypermethylation, resulting in downregulation of RGMA expression in BC. In contrast, RGMA overexpression suppressed BC cell proliferation and colony-formation capabilities and increased BC cell apoptosis. Furthermore, RGMA knockdown accelerated BC cell proliferation and suppressed cellular apoptosis in vitro and in vivo. Reversal of RGMA promoter methylation with 5-Aza-CdR restored RGMA expression and blocked tumor growth. Overall, DNMT1- and DNMT3A-mediated RGMA promoter hypermethylation led to downregulation of RGMA expression, and low RGMA expression contributed to BC growth via activation of the FAK/Src/PI3K/AKT-signaling pathway. Our data thus suggested that RGMA might be a promising therapeutic target in BC.

Physiological Roles of Red Carrot Methanolic Extract and Vitamin E to Abrogate Cadmium-Induced Oxidative Challenge and Apoptosis in Rat Testes: Involvement of the Bax/Bcl-2 Ratio

The precise analysis of the contents of the red carrot is still ambiguous and its role in the maintenance of male fertility needs to be further reconnoitered. Hence, this study targets the physiological impacts of either red carrot methanolic extract (RCME) or vitamin E (Vit. E), co-administrated with cadmium chloride (CdCl₂) on rat testes, specifically those concerned with apoptosis and oxidative challenge. Four groups of adult male rats (n = 12) are used; control, CdCl₂, CdCl₂ + Vit. E and CdCl₂ + RCME. LC-MS analysis of RCME reveals the presence of 20 different phytochemical compounds. Our data clarify the deleterious effects of CdCl₂ on testicular weights, semen quality, serum hormonal profile, oxidative markers and Bax/Bcl-2 ratio. Histopathological changes in testicular, prostatic and semen vesicle glandular tissues are also observed. Interestingly, our data clearly demonstrate that co-administration of either RCME or Vit. E with CdCl₂ significantly succeeded in the modulation (p < 0.05) of all of these negative effects. The most striking is that they were potent enough to modulate the Bax/Bcl-2 ratio as well as having the ability to correct the impaired semen picture, oxidant status and hormonal profile. Thus, RCME and Vit. E could be used as effective prophylactic treatments to protect the male reproductive physiology against CdCl₂ insult.

Protective effects of selenium yeast against cadmium-induced necroptosis through miR-26a-5p/PTEN/PI3K/AKT signaling pathway in chicken kidney

Cadmium (Cd) is a ubiquitous environmental pollutant of increasing worldwide concern to both humans and animals. Selenium yeast (Se-Y) is an organic selenium source that has been shown an advantage in antagonizing Cd-induced liver necroptosis in chicken. Herein, we described the discovery path of Se-Y antagonism in Cd-induced renal necroptosis in chicken through targeting miR-26a-5p/PTEN/PI3K/AKT signaling pathway. We set up four groups of chickens at random: control group (0.5 mg/kg Na₂SeO₃), Se-Y group (0.5 mg/kg Se-Y), Se-Y+Cd group (0.5 mg/kg Se-Y and 150 mg/kg CdCl₂) and Cd group (150 mg/kg CdCl₂ and 0.5 mg/kg Na₂SeO₃). Interestingly, we found Se-Y, but not Na₂SeO₃, significantly blocked Cd accumulation in the kidney and alleviated Cd-induced necroptosis through inhibiting the expression of RIP1, RIP3 and MLKL. Se-Y, activated miR-26a-5p expression, thereby down-regulated the expression of PTEN, resulting in the up-regulation of PI3K/AKT signaling pathway and the inhibition of oxidative stress in both Se-Y and Cd treated chickens. Besides that, Se-Y could also specifically reduce the expression levels of heat shock protein 60 (HSP60), HSP70 and HSP90 in Se-Y and Cd co-treated chickens. Taken together, our results showed that Se-Y has an added value to antagonize Cd-induced necroptosis in chicken kidney by regulating the miR-26a-5p/PTEN/PI3K/AKT signaling pathway and HSPs, indicating that Se-Y could serve as an effective antagonist on Cd-induced renal necroptosis in chickens.

Albicanol antagonizes Cd-induced apoptosis through a NO/iNOS-regulated mitochondrial pathway in chicken liver cells

Cadmium (Cd) induces hepatocyte injury by oxidative stress. Albicanol is a sesquiterpenoid extracted from the medicinal plant Dryopteris fragrans that has previously been shown to exhibit anti-aging and antioxidant activity. In this study, we explored the mechanism of albicanol inhibition of the Cd-induced apoptosis of chicken hepatoma cells (LMH) by treating these cells with CdCl2 (25 μM) and/or albicanol (2.5 × 10-5 μg mL-1) for 24 h. Under Cd treatment, the research results showed that the apoptosis rate markedly increased in LMH cells. In addition, the iNOS activity and NO content increased significantly, which promoted the expressions of genes associated with the mitochondrial apoptosis pathway (Bax, CytC, Caspase-3 and Caspase-9) and inhibited the expression of Bcl-2 in this pathway. However, Cd + albicanol co-treatment significantly reduced the apoptosis rate and the expressions of iNOS and genes associated with the mitochondrial apoptosis pathway (Bax, CytC, Caspase-3 and Caspase-9), and promoted the expression of Bcl-2 in this pathway. In addition, molecular docking supported a link between the albicanol ligand and the iNOS receptor. These results indicated that albicanol can inhibit Cd-induced apoptosis by regulating the NO/iNOS-mediated mitochondrial pathway.

MicroRNA-363-3p promotes apoptosis in response to cadmium-induced renal injury by down-regulating phosphoinositide 3-kinase expression

We previously determined that specific microRNAs (miRNAs) are involved in renal pathophysiological occurrences induced by cadmium (Cd) in rats. This study expands our studies on miRNAs, determining their role in Cd-induced nephrotoxicity in occupational workers. We performed miRNA microarray analyses of blood and urine samples from patients diagnosed as occupational chronic Cd poisoning (OCCP) with abnormally elevated concentrations of urinary beta-2-microglobulin (U-β₂-MG), an indicator of tubular proteinuria. We also performed in vitro bioinformatics-based investigations of apoptosis-related genes targeted by miRNAs involved in the biological response to Cd exposure. We tested five differentially expressed miRNAs and determined a significant increase of sera miR-363-3p. Also, we determined that miR-363-3p increase is associated with phosphoinositide 3-kinase (PI3K) down-regulation and the suppressed proliferation and enhanced apoptosis of renal tubule epithelial cells. The obtained results suggest miR-363-3p involvement in the pathophysiology of Cd-induced renal injury in humans and maybe considered for possible interventional therapeutic strategies for Cd-associated kidney damage.

Transcriptome sequencing reveals genes involved in cadmium-triggered oxidative stress in the chicken heart

As a ubiquitous heavy metal, cadmium (Cd) is highly toxic to various organs. However, the effects and molecular mechanism of Cd toxicity in the chicken heart remain largely unknown. The goal of our study was to investigate the cardiac injury in chickens' exposure to Cd. We detected the levels of oxidative stress-related molecules in the Cd-induced chicken heart, and assessed the histopathological changes by hematoxylin and eosin staining. RNA sequencing was performed to identify differentially expressed mRNAs between the Cd-induced group and control group. The expression of candidate genes involved in oxidative stress was certified by quantitative reverse transcription PCR. Our results showed that the expression of glutathione, peroxidase, and superoxide dismutase was significantly decreased and malondialdehyde was increased in the heart of chickens by Cd induction. The disorderly arranged cardiomyocytes, swelled and enlarged cells, partial cardiomyocyte necrosis, blurred morphological structure, and notable inflammatory cell infiltration were observed in the Cd-induced chicken heart. RNA sequencing identified 23 upregulated and 11 downregulated mRNAs in the heart tissues of the chicken in the Cd-induced group, and functional pathways indicated that they were associated with oxidative stress. Moreover, CREM, DUSP8, and ITGA11 expressions were significantly reduced, whereas LAMA1 expression was induced in heart tissue of chickens by Cd treatment. Overall, our findings revealed that oxidative stress and pathological changes in the chicken heart could be triggered by Cd. The mRNA transcriptional profiles identified differentially expressed genes in the chicken heart by Cd induction, revealing oxidative stress-related key genes and enhancing our understanding of Cd toxicity in the chicken heart.

Typical phthalic acid esters induce apoptosis by regulating the PI3K/Akt/Bcl-2 signaling pathway in rat insulinoma cells

Di-(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) are representative phthalic acid esters (PAEs), a class of environmental endocrine disruptors used as plasticizers. PAEs exposure is associated with glucose metabolism, insulin resistance, and glucose tolerance; however, the mechanism and various PAE effects on human glucose metabolism remain largely unknown. In this study, we investigated the effects of DEHP, DBP, and their mixture on rat insulinoma (INS-1) cell apoptosis and the mechanism involved in vitro. The INS-1 cells were cultured in RPMI-1640 + 10% fetal bovine serum for 24 h and pretreated with dimethyl sulfoxide (vehicle, <0.1%), DEHP (30 μM), DBP (30 μM), and their mixture (30 μM DEHP + 30 μM DBP). The methyl-thiazolyl tetrazolium bromide test was used to measure cell viability. Hoechst 33342/propidium iodide (PI) staining and Annexin V-FITC/PI staining, 2',7'-dichlorofluorescein diacetate assay, and glucose-induced insulin secretion assay were used to detect cell apoptosis rates, intracellular reactive oxygen species (ROS), and insulin secretion in INS-1, respectively. The mRNA expression levels of Bcl-2, Bax, Caspase 9, Caspase 8, Caspase 3, phosphoinositide 3-kinase (PI3K), and Akt were detected using real-time quantitative reverse transcription PCR; their protein expression levels were detected using western blotting. To the best of our knowledge, this study was the first to show that the combined effect of the two PAEs promotes a ROS-mediated PI3K/Akt/Bcl-2 pathway-induced pancreatic β cell apoptosis that is significantly higher than the effects of each PAE. Thus, safety standards and studies do not consider this effect as a significant oversight when blending PAEs. We assert that this must be addressed and corrected for establishing more impactful and safer standards.

Activation of autophagy by sitagliptin attenuates cadmium-induced testicular impairment in rats: Targeting AMPK/mTOR and Nrf2/HO-1 pathways

AIMS

Cadmium (Cd) is a prevalent environmental contaminant that incurs deleterious health effects, including testicular impairment. Sitagliptin, a selective dipeptidyl peptidase-4 (DPP-4) inhibitor, has demonstrated marked cardio-, hepato-, and reno-protective actions, however, its impact on Cd-triggered testicular dysfunction has not been formerly investigated. Hence, the present study aimed to explore the probable beneficial impact of sitagliptin against Cd-evoked testicular impairment which may add to its potential clinical utility. The underlying mechanisms pertaining to the balance between testicular autophagy and apoptosis were explored, including the AMPK/mTOR and Nrf2/HO-1 pathways.

MATERIALS AND METHODS

The testicular tissues were examined using histopathology, immunohistochemistry, Western blotting, and ELISA. Sitagliptin (10 mg/kg/day, by gavage) was administered for 4 consecutive weeks.

KEY FINDINGS

Sitagliptin attenuated the testicular impairment via improvement of the relative testicular weight, sperm count/motility, sperm abnormalities, and serum testosterone. Additionally, sitagliptin counteracted Cd-induced histologic aberrations/disrupted spermatogenesis. Interestingly, sitagliptin augmented the defective autophagy as demonstrated by upregulating Beclin 1 protein expression and lowering p62 SQSTM1 protein accumulation. These effects were mediated via the activation of testicular AMPK/mTOR pathway as proven by increasing p-AMPK (Ser485, Ser491)/total AMPK and diminishing p-mTOR (Ser2448)/total mTOR protein expression. Additionally, sitagliptin suppressed the testicular apoptotic events via downregulating Bax and upregulating Bcl-2 protein expression. In tandem, sitagliptin suppressed the oxidative stress through lowering lipid peroxides and activating Nrf2/HO-1 pathway via upregulating the protein expression of Nrf2, and the downstream effectors HO-1 and GPx.

SIGNIFICANCE

Sitagliptin attenuated Cd-induced testicular injury via boosting the autophagy/apoptosis ratio through activation of AMPK/mTOR and Nrf2/HO-1 pathways.

Cadmium-induced oxidative stress promotes apoptosis and necrosis through the regulation of the miR-216a-PI3K/AKT axis in common carp lymphocytes and antagonized by selenium

Cadmium (Cd) is a primary environmental pollutant which causes the immune dysfunction of aquatic animals. MicroRNAs (miRNAs) play a key role in programmed necrosis and apoptosis of immune organs. Selenium (Se), known as an important element, can antagonize Cd toxicity in birds, but the impact of Se on common carps (Cyprinus carpio) has not been reported. To investigate the Cd-induced immunotoxicity mechanism mediated by miR-216a in splenic lymphocytes of common carp and antagonized by Se, we extracted lymphocytes from the spleen and divided them into control group, Se group (10^-6 mol/L of Na₂SeO₃), Se + Cd group and Cd group (4 × 10^-5 mol/L of CdCl₂). After 6 h of incubation, AO/EB staining, Flow cytometry, qPCR and Western blot were performed. The results showed that Cd exposure caused the apoptosis (BAX, Bcl-2, Caspase 3, Caspase 9) and programmed necrosis (RIP, RIP3, MLKL) in lymphocytes, increased the expression of CYP enzymes, glycometabolism-related enzymes and production of ROS, while irritated the oxidative stress (MDA, SOD, CAT and GSH-PX), upregulated the expression of miR-216a which attenuated the levels of PI3K. However, those variations were apparently mitigated in the Se + Cd group. In short, we have proven that Cd activates oxidative stress and miR-216a-PI3K/AKT axis disorder, thus promoting apoptosis and necrosis in lymphocytes. Moreover, Se can antagonize Cd-triggered apoptosis and necrosis in lymphocytes.

Linking molecular targets of Cd in the bloodstream to organ-based adverse health effects

The chronic exposure of human populations to toxic metals remains a global public health concern. Although chronic Cd exposure is linked to kidney damage, osteoporosis and cancer, the underlying biomolecular mechanisms remain incompletely understood. Since other diseases could also be causally linked to chronic Cd exposure, a systems toxicology-based approach is needed to gain new insight into the underlying exposure-disease relationship. This approach requires one to integrate the cascade of dynamic bioinorganic chemistry events that unfold in the bloodstream after Cd enters with toxicological events that unfold in target organs over time. To this end, we have conducted a systematic literature search to identify all molecular targets of Cd in plasma and in red blood cells (RBCs). Based on this information it is impossible to describe the metabolism of Cd and the toxicological relevance of it binding to molecular targets in/on RBCs is elusive. Perhaps most importantly, the role that peptides, amino acids and inorganic ions, including HCO₃^-, Cl^- and HSeO₃^- play in terms of mediating the translocation of Cd to target organs and its detoxification is poorly understood. Causally linking human exposure to this metal with diseases requires a much better integration of the bioinorganic chemistry of Cd that unfolds in the bloodstream with target organs. This from a public health point of view important goal will require collaborations between scientists from different disciplines to untangle the complex mechanisms which causally link Cd exposure to disease.

Protective effect of quercetin on rat testes against cadmium toxicity by alleviating oxidative stress and autophagy

Cadmium (Cd), a highly toxic heavy metal, adversely affects human and animal health. Quercetin (Que) is a kind of flavonoid that can protect many tissues from the toxic effect of heavy metals. Although many studies have explored the adverse effects of cadmium on rats and other animals, the mechanism of Cd-induced testicular autophagy and the antagonistic effect of Que on cadmium remain unclear. In this study, Sprague-Dawley rats were treated with Cd, Que or Cd, and Que supplements to explore the mechanisms of Que-alleviated testis injury caused by Cd exposure. The rat body weight and relative testicular weight were measured. Morphological changes in testes and indices of oxidative stress were also examined. The expression levels of autophagy-related genes were detected as well. Results showed that Cd decreased the rat body weight and relative testicular weight and induced pathological changes in testes. Conversely, Que alleviated these changes. We also found that Cd increased the malondialdehyde content and decreased the contents of total superoxide dismutase, glutathione peroxidase, catalase, and glutathione. Moreover, the protein expression levels of P62 and LC3-II increased under Cd exposure conditions. Conversely, Que obviously alleviated these toxic activities induced by Cd. Overall, this study showed that Cd accumulated in rat testes, leading to oxidative stress and autophagy. Que can reduce cadmium toxicity by reducing oxidative stress and inhibiting autophagy. The specific mechanism of Que antagonizing Cd toxicity can provide new insights into countering cadmium toxicity.

Renal changes and apoptosis caused by subacute exposure to Aroclor 1254 in selenium-deficient and selenium-supplemented rats

Aroclor 1254 (A1254), a mixture of polychlorinated biphenyls, exerts hepatic, renal, and reproductive toxicity in rodents. This study aimed to determine a protective role of selenium on histopathological changes, oxidative stress, and apoptosis caused by A1254 in rat kidney. It included a control group, which received regular diet containing 0.15 mg/kg Se (C), a Se-supplemented group (SeS) receiving 1 mg/kg Se, a Se-deficient group (SeD) receiving Se-deficient diet of ≤0.05 mg/kg Se, an A1254-treated group (A) receiving 10 mg/kg of Aroclor 1254 and regular diet, an A1254-treated group receiving Se-supplementation (ASeS), and an A1254-treated group receiving Se-deficient diet (ASeD). Treatments lasted 15 days. After 24 h of the last dose of A1254, the animals were decapitated under anaesthesia and their renal antioxidant enzyme activities, lipid peroxidation (LP), glutathione, protein oxidation, and total antioxidant capacity levels measured. Histopathological changes were evaluated by light and electron microscopy. Apoptosis was detected with the TUNEL assay. Kidney weights, CAT activities, and GSH levels decreased significantly in all A1254-treated groups. Renal atrophic changes and higher apoptotic cell counts were observed in the A and ASeD groups. Both groups also showed a significant drop in GPx1 activities (A – 34.92 % and ASeD – 86.46 %) and rise in LP (A – 30.45 % and ASeD – 20.44 %) vs control. In contrast, LP levels and apoptotic cell counts were significantly lower in the ASeS group vs the A group. Histopathological changes and renal apoptosis were particularly visible in the ASeD group. Our findings suggest that selenium supplementation provides partial protection against renal toxicity of Aroclor 1254.

Liver-derived exosome-laden lncRNA MT1DP aggravates cadmium-induced nephrotoxicity

Cadmium (Cd) is a well-characterized toxic heavy metal which could cause severe kidney injury. However, currently the knowledge of Cd toxicity towards kidney is still insufficient. Our previous data has identified that MT1DP (metallothionein 1D pseudogene) could promote Cd-induced detrimental effects on hepatocytes. Herein, we further found that MT1DP was also an important intermediate to aggravate Cd-induced nephrotoxicity. Through analyzing the data of 100 residents from Cd-contaminated area in Southern China, we found that the blood MT1DP levels correlated to the urine Cd content and the extent of nephrotoxicity. Although MT1DP was predominantly induced by hepatocytes in the liver, liver-secreted MT1DP was found to be packaged into extracellular cargoes: exosomes, by which MT1DP was delivered into circulation and thereafter targeted kidney cells. Furthermore, exosome-laden MT1DP worsened Cd-induced nephrotoxicity, as evidenced in both Cd-poisoned individuals and in vitro cells. Moreover, MT1DP was found to reinforce Cd-induced toxicity in kidney cells by indirectly breaking the equilibrium between the pro-apoptotic and anti-apoptotic effects conducted by BAX and Bcl-xL, respectively. Collectively, our data unveiled that hepatocyte-derived MT1DP depends on the delivery of exosomes to wreak considerable havoc in Cd nephrotoxicity. This study offers new insights into the molecular mechanisms of Cd-induced kidney injury.

The Role of Selenium in Arsenic and Cadmium Toxicity: an Updated Review of Scientific Literature

Arsenic (As) and cadmium (Cd) are elements arousing major public health concerns associated with environmental pollution, high toxicity potential, and carcinogenic nature. However, selenium (Se) at low doses and incorporated into enzymes and proteins has antioxidant properties and protects animals and humans from the risk of various diseases. It also has an exceptionally narrow range between necessary and toxic concentrations, which is a well-known hindrance in its use as a dietary supplement. The present article aims to update and expand the role of Se in As and Cd toxicity discussed in our earlier paper. In general, recent reports show that Se, regardless of its form (as selenite, selenomethionine, nanoSe, or Se from lentils), can reduce As- or Cd-mediated toxicity in the liver, kidney, spleen, brain, or heart in animal models and in cell culture studies. As was suggested in our earlier review, Se antagonizes the toxicity of As and Cd mainly through sequestration of these elements into biologically inert complexes and/or through the action of Se-dependent antioxidant enzymes. An increase in the As methylation efficiency is proposed as a possible mechanism by which Se can reduce As toxicity. However, new studies indicate that Se may also diminish As or Cd toxicity by activation of the Nrf2 pathway. In addition, this paper discusses possible signs of Se toxic effects, which may be a challenge for its future use in the therapy of As and Cd poisoning and provide future directions to address this issue.

Genipin attenuates mitochondrial-dependent apoptosis, endoplasmic reticulum stress, and inflammation via the PI3K/AKT pathway in acute lung injury

The protective effects of genipin against lipopolysaccharide (LPS)-induced acute lung injury (ALI) have been reported; however, the mechanism is unclear. Genipin performs its pharmacological effects via activation of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. In the present study, we aimed to determine whether the PI3K/AKT pathway is involved in the protective effects of genipin against mitochondrial-dependent apoptosis, endoplasmic reticulum stress (ERS), and inflammation in ALI. We constructed in vivo and in vitro models of LPS-induced ALI. PI3K/AKT signaling was inhibited using LY294002. Pretreatment with genipin increased AKT phosphorylation, indicating that PI3K/AKT signaling was upregulated. Genipin pretreatment prevented LPS-induced histopathological deterioration, increased pulmonary edema, and decreased oxygenation index, all of which were inhibited using LY294002. In addition, genipin pretreatment attenuated LPS-mediated mitochondrial apoptosis, as indicated by improved mitochondrial dysfunction, downregulation of BAX (BCL2 associated X, apoptosis regulator), upregulation of BCL2 (BCL2 apoptosis regulator), inhibited the release of cytochrome c, activation of caspase-3, and cell apoptosis. Genipin pretreatment inhibited the LPS-induced upregulation of AF4/FMR2 family member 4 (CHOP), glucose-regulated protein, 78 kDa (GRP78), and X-box binding protein 1 (XBP1) levels, indicating ERS suppression. Moreover, genipin pretreatment alleviated LPS-induced inflammation, indicating by blockade of nuclear factor kappa b (NF-κB) signaling activation and reduced tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, and IL-6 levels in the lung and bronchoalveolar lavage fluid. LY294002 could inhibit these genipin-induced protective effects against apoptosis, ERS, and inflammation. Thus, genipin significantly activates PI3K/AKT signaling to ameliorate mitochondria-dependent apoptosis, ERS, and inflammation in LPS-induced ALI.

The protective effect of grape skin or purple carrot extracts against cadmium intoxication in kidney of rats

The aim of this study was to evaluate the protective effect of grape skin or purple carrot extracts against cadmium-induced intoxication in rats' kidneys. For this purpose, 30 male Wistar rats were distributed into six groups (n = 5), as follows: control group; cadmium group and groups treated with grape skin at 175 or 350 mg / L doses; or purple carrot extract at 400 mg / L or 800 mg / L doses, by drinking water. In the group exposed to cadmium, histopathological analysis revealed severe tissue injury as a result of coagulation necrosis, congested vessels and inflammatory infiltrate. Animals treated with grape skin or purple carrot extracts improved the histopathological changes induced by cadmium. 8-OHdG immunoexpression and catalase gene expression decreased in rats treated with purple carrot or grape skin extracts. Grape skin extract was able to increase SOD-CuZn gene expression as well. Toll-like signaling pathway (TLR2, PIKK and TRAF6) and cytochrome c expressions were not altered after the treatment with grape skin or purple carrot extracts. Taken together, we conclude that grape skin and purple carrot extracts had a protective effect on the rats' kidneys after cadmium intoxication, by means of tissue regenerating tissue regeneration and antioxidant properties, grape skin extract being more effective for this purpose.

Protective effects of Ganoderma lucidum triterpenoids on oxidative stress and apoptosis in the spleen of chickens induced by cadmium

Cadmium (Cd) is a heavy metal that poses a huge potential threat to human and animal health. Therefore, it is necessary to study its damage mechanism. In the present study, we have examined the protective effects of Ganoderma lucidum triterpenoids on oxidative stress and apoptosis in the spleen of chickens induced by Cd. One hundred and twenty healthy Hailan white chickens (7-day-old) were randomly divided into the following four groups: control group, Cd group, triterpenoid group, and Cd-triterpenoid group. The chickens were euthanized on the 20th, 40th, and 60th days, and the spleens were removed. Cd and malondialdehyde (MDA) content, antioxidant enzyme (superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px)) activities, and inflammatory factor (tumor necrosis factor alpha (TNF-α) and interleukin (IL-1β and IL-6)) and apoptotic factor (caspase-3, BAX, and Bcl-2) expressions were detected. The results showed that Ganoderma lucidum triterpenoids could reduce the content of Cd and MDA; increase the antioxidant enzyme activities (SOD and GSH-Px); decrease the expression of inflammatory factors (TNF-α) and interleukin (IL-1β and IL-6); increase the expression of apoptotic factor (Bcl-2); and decrease the expression of apoptotic factors (caspase-3 and Bax). It showed that the triterpenoids of Ganoderma lucidum had significant protective effects on oxidative stress and apoptosis of chicken spleen, which provided a theoretical basis for further prevention and treatment of cadmium poisoning.

Antioxidant Defence Systems and Oxidative Stress in Poultry Biology: An Update

Poultry in commercial settings are exposed to a range of stressors. A growing body of information clearly indicates that excess ROS/RNS production and oxidative stress are major detrimental consequences of the most common commercial stressors in poultry production. During evolution, antioxidant defence systems were developed in poultry to survive in an oxygenated atmosphere. They include a complex network of internally synthesised (e.g., antioxidant enzymes, (glutathione) GSH, (coenzyme Q) CoQ) and externally supplied (vitamin E, carotenoids, etc.) antioxidants. In fact, all antioxidants in the body work cooperatively as a team to maintain optimal redox balance in the cell/body. This balance is a key element in providing the necessary conditions for cell signalling, a vital process for regulation of the expression of various genes, stress adaptation and homeostasis maintenance in the body. Since ROS/RNS are considered to be important signalling molecules, their concentration is strictly regulated by the antioxidant defence network in conjunction with various transcription factors and vitagenes. In fact, activation of vitagenes via such transcription factors as Nrf2 leads to an additional synthesis of an array of protective molecules which can deal with increased ROS/RNS production. Therefore, it is a challenging task to develop a system of optimal antioxidant supplementation to help growing/productive birds maintain effective antioxidant defences and redox balance in the body. On the one hand, antioxidants, such as vitamin E, or minerals (e.g., Se, Mn, Cu and Zn) are a compulsory part of the commercial pre-mixes for poultry, and, in most cases, are adequate to meet the physiological requirements in these elements. On the other hand, due to the aforementioned commercially relevant stressors, there is a need for additional support for the antioxidant system in poultry. This new direction in improving antioxidant defences for poultry in stress conditions is related to an opportunity to activate a range of vitagenes (via Nrf2-related mechanisms: superoxide dismutase, SOD; heme oxygenase-1, HO-1; GSH and thioredoxin, or other mechanisms: Heat shock protein (HSP)/heat shock factor (HSP), sirtuins, etc.) to maximise internal AO protection and redox balance maintenance. Therefore, the development of vitagene-regulating nutritional supplements is on the agenda of many commercial companies worldwide.

Myo-inositol in the protection from cadmium-induced toxicity in mice kidney: An emerging nutraceutical challenge

Cadmium (Cd) induces functional and morphological changes in kidney. Therefore, the effects of a natural nutraceutical antioxidant, myo-inositol (MI), were evaluated in mice kidneys after Cd challenge. Twenty-eight C57 BL/6 J mice were divided into these groups: 0.9% NaCl; MI (360 mg/kg/day); CdCl₂ (2 mg/kg/day) plus vehicle; CdCl₂ (2 mg/kg/day) plus MI (360 mg/kg/day). After 14 days, kidneys were processed for structural, biochemical and morphometric evaluation. Treatment with CdCl₂ increased urea nitrogen and creatinine in serum and augmented tumor necrosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS) expression. Furthermore, monocyte chemoattractant protein-1 (MCP-1), kidney injury molecule-1 (KIM-1) and myo-inositol oxygenase (MIOX) immunoreactivity, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells number were significantly higher than control and MI groups. Glutathione (GSH) content and glutathione peroxidase (GPx) activity were reduced and structural changes were evident. The treatment with MI significantly lowered urea nitrogen and creatinine levels, TNF-α and iNOS expression, MCP-1, KIM-1 and MIOX immunoreactivity and TUNEL positive cells number, increased GSH content and GPx activity and preserved kidney morphology. A protection of MI against Cd-induced damages in mice kidney was demonstrated, suggesting a strong antioxidant role of this nutraceutical against environmental Cd harmful effects on kidney lesions.

Alterations in transcriptome and antioxidant activity of naturally aged mice exposed to selenium-rich rice

Selenium (Se) is a vital element which leads to strong antioxidation in animals and humans. However, the mechanism underlying natural cereal Se-induced biological changes is not well understood. This study intended to explore the gene differential expression in naturally aged mice exposed to selenium by RNA-Seq technique. A total spectrum of 53 differentially expressed genes was quantified in mice heart tissues treated with Se-rich and general rice. The GO functional annotation of differentially expressed genes disclosed the enrichment of cellular process, ionic binding, biological regulation, and catalytic activity. One hundred twenty-three differential pathways (cardiovascular diseases, immune system, transport and catabolism, longevity regulating, and PI3K-AKT signaling) were identified according to KEGG metabolic terms. Afterwards, the effect of Se-rich rice on the antioxidant activity was assessed. The selenium-rich diet increased the total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in mice serum and livers while significantly reduces methane dicarboxylic aldehyde (MDA) contents. FOXO1 and FOXO3 genes, which acted as the regulators of apoptosis and the antioxidant enzyme, were significantly enhanced in mice when fed with Se-rich rice. In short, the present findings disclosed the alluring insights of organic and inorganic selenium sources on certain biological processes and antioxidant activity of living bodies. However, long-term trials are still required to draw a definitive conclusion, including risks and benefit analysis for various management strategies.

Royal jelly attenuates cadmium-induced nephrotoxicity in male mice

Cadmium exposure induces nephrotoxicity by mediating oxidative stress, inflammation, and apoptosis. The purpose of this study was to examine the protective effect of royal jelly on Cd-induced nephrotoxicity. Adult male mice were distributed randomly into 4 clusters: untreated, royal jelly-treated (85 mg/kg, oral), CdCl₂-treated (6.5 mg/kg, intraperitoneal), and pretreated with royal jelly (85 mg/kg) 2 h before CdCl₂ injection (6.5 mg/kg, intraperitoneal) for seven consecutive days. Cd concentration in the renal tissue and absolute kidney weight of the Cd-treated mice were significantly higher than those of control group. The levels of kidney function markers, kidney injury molecules-1 (KIM-1), metallothionein, lipid peroxidation, nitric oxide, tumor necrosis factor-α, interleukin-1β, and the apoptosis regulators Bax and caspases-3 also increased significantly in the renal tissue of Cd-treated mice, whereas the levels of glutathione, antioxidant enzyme activities, and the apoptosis inhibitor Bcl-2 were significantly reduced in the renal tissue of Cd-treated group. Histopathological studies showed vacuolation and congested glomeruli in the kidney tissue of Cd-treated mice. However, all aforementioned Cd-induced changes were attenuated by pretreatment with royal jelly. We therefore concluded that royal jelly attenuated Cd-induced nephrotoxicity and it is suggested that this nephroprotective effect could be linked to its ability to promote the nuclear factor erythroid 2–related factor 2 (Nrf2)/antioxidant responsive element (ARE) pathway.

Knockdown of serpin peptidase inhibitor clade C member 1 inhibits the growth of nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a type of cancer originating in the nasopharynx. There are no NPC‑specific treatments available at present. Serpin peptidase inhibitor clade C member 1 (SERPINC1) serves roles in anticoagulation and anti‑inflammation. The aim of the present study was to investigate the role of SERPINC1 in the proliferation and apoptosis of NPC cells. Tumor and adjacent healthy tissue samples were collected from patients with NPC. Additionally, the SERPINC1 gene was silenced in the HNE3 cell line using short interfering RNA targeted against SERPINC1 (SERPINC1‑siRNA). Cell viability was determined via a Cell Counting Kit‑8 assay; furthermore, proliferation and apoptosis were investigated via flow cytometry. Western blotting and reverse transcription‑quantitative polymerase chain reaction analysis were performed to determine the expression levels of protein and mRNA. It was revealed that the expression levels of SERPINC1 mRNA and protein were increased in NPC tumor tissues compared with in adjacent healthy tissues. The expression of SERPINC1 mRNA and protein in HNE3 cells decreased following SERPINC1‑siRNA transfection. Furthermore, knockdown of SERPINC1 promoted apoptosis and inhibited proliferation. It was also demonstrated that silencing SERPINC1 upregulated the expression of B‑cell lymphoma-2 (Bcl‑2)‑associated X protein and p53 mRNA and protein, and downregulated that of Bcl‑2, survivin and cyclin D1. Downregulation of SERPINC1 reduced the phosphorylation of phosphatidylinositol 3‑kinase (PI3K), protein kinase B (Akt) and mammalian target of rapamycin (mTOR). Thus, SERPINC1 knockdown may promote the apoptosis of HNE3 cells and inhibit proliferation via the suppression of the PI3K/Akt/mTOR signaling pathway.

Modelling cadmium-induced cardiotoxicity using human pluripotent stem cell-derived cardiomyocytes

Cadmium, a highly ubiquitous toxic heavy metal, has been widely recognized as an environmental and industrial pollutant, which confers serious threats to human health. The molecular mechanisms of the cadmium-induced cardiotoxicity (CIC) have not been studied in human cardiomyocytes at the cellular level. Here we showed that human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) can recapitulate the CIC at the cellular level. The cadmium-treated hPSC-CMs exhibited cellular phenotype including reduced cell viability, increased apoptosis, cardiac sarcomeric disorganization, elevated reactive oxygen species, altered action potential profile and cardiac arrhythmias. RNA-sequencing analysis revealed a differential transcriptome profile and activated MAPK signalling pathway in cadmium-treated hPSC-CMs, and suppression of P38 MAPK but not ERK MAPK or JNK MAPK rescued CIC phenotype. We further identified that suppression of PI3K/Akt signalling pathway is sufficient to reverse the CIC phenotype, which may play an important role in CIC. Taken together, our data indicate that hPSC-CMs can serve as a suitable model for the exploration of molecular mechanisms underlying CIC and for the discovery of CIC cardioprotective drugs.

The Protective Effect of Selenium on the Chicken Pancreas against Cadmium Toxicity via Alleviating Oxidative Stress and Autophagy

Cadmium (Cd) is a highly toxic heavy metal that can affect human and animal health. Selenium (Se) is an essential microelement that can protect various organs against toxic heavy metals. Although many studies have investigated the adverse effect of Cd in rats and several other animals, little is known regarding the mechanisms of Cd-induced autophagy in the chicken pancreas and the antagonistic effect of Se on Cd. In the current study, we fed chickens Se, Cd, or Se and Cd supplements to establish the Se and Cd interaction model and to measure the concentrations of Se and Cd in the chicken pancreas. The ultrastructure changes of the chicken pancreas were also observed, and we detected oxidative stress indexes in each group. The expression levels of autophagy-related genes were also examined. We found that Cd exposure could increase the concentration of Cd, the activities of total superoxide dismutase (T-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px); and the total antioxidant capacity (T-AOC) content in the chicken pancreas. The protein expression levels of dynein, Beclin1, LC3-1, LC3-2, and Atg5 were increased and that of TOR was decreased under Cd exposure conditions. However, the changes induced by Cd were significantly alleviated by Se. This study suggested that Cd could accumulate in the chicken pancreas and lead to oxidative stress and autophagy. Se was shown to antagonize Cd toxicity though reducing Cd accumulation, alleviating oxidative stress, and inhibiting autophagy. This study revealed a concrete mechanism for the Se antagonism of Cd and might provide a new clue for the detoxification of Cd poisoning.

ERK1/2 MAPK promotes autophagy to suppress ER stress-mediated apoptosis induced by cadmium in rat proximal tubular cells

Cadmium (Cd) is a toxic heavy metal and its toxic mechanism is not entirely clear. The goal of the present study was to investigate the toxic mechanism of Cd on rPT cells, and to elucidate the role of ERK1/2 signaling pathway in mediating the relationship between apoptosis and autophagy. We evaluated the cell morphology, cell cycle distribution, apoptosis rates, and the expression of related proteins. We observed that increased Cd concentration disrupted cell morphology, increased apoptosis and induced autophagy. Additionally, activation of JNK1/2 and p38 MAPK promoted apoptosis, while activation of ERK1/2 inhibited apoptosis. Upon inhibition of autophagy, apoptosis rate and the expression of ER proteins related to the apoptosis were increased. Following inhibition of the ERK1/2 signaling pathway, the number of LC3 aggregates, the rate of LC3II/LC3I and the expression of Beclin-1were decreased, but the expression level of ER proteins related to apoptosis were increased. Our results indicated that Cd exposure damages cells also induces apoptosis and autophagy, meanwhile demonstrate that the ERK1/2 signaling pathway plays an important role in this process. Besides, these data suggest that autophagy can inhibit Cd-induced apoptosis and the ERK1/2 signaling pathway can suppress ER stress-mediated apoptosis by activating autophagy.

A Summary of New Findings on the Biological Effects of Selenium in Selected Animal Species-A Critical Review

Selenium is an essential trace element important for many physiological processes, especially for the functions of immune and reproductive systems, metabolism of thyroid hormones, as well as antioxidant defense. Selenium deficiency is usually manifested by an increased incidence of retention of placenta, metritis, mastitis, aborts, lowering fertility and increased susceptibility to infections. In calves, lambs and kids, the selenium deficiency demonstrates by WMD (white muscle disease), in foals and donkey foals, it is associated with incidence of WMD and yellow fat disease, and in pigs it causes VESD (vitamin E/selenium deficiency) syndrome. The prevention of these health disorders can be achieved by an adequate selenium supplementation to the diet. The review summarizes the survey of knowledge on selenium, its biological significance in the organism, the impact of its deficiency in mammalian livestock (comparison of ruminants vs. non-ruminants, herbivore vs. omnivore) and possibilities of its peroral administration. The databases employed were as follows: Web of Science, PubMed, MEDLINE and Google Scholar.