Selenium-Alleviated Testicular Toxicity by Modulating Inflammation, Heat Shock Response, and Autophagy Under Oxidative Stress in Lead-Treated Chickens

p38MAPK/HSPB1 is involved in the regulatory effects of selenomethionine on the apoptosis, viability and testosterone secretion of sheep Leydig cells exposed to heat

Testosterone derived from testicular Leydig cells (LCs) is important for male sheep, and the testis is susceptible to external temperature. The present study aimed to explore the alleviating effect of selenomethionine (Se-Met) on heat-induced injury in Hu sheep LCs. Isolated LCs were exposed to heat (41.5°C, heat exposure, HE) or not (37°C, nonheat exposure, NE), and cells in NE and HE were treated with 0 (C) or 8 μmol/L (S) Se-Met for 6 h. Cell viability, testosterone level, and the expression of GPX1, HSD3B, apoptosis-related genes and p38 mitogen-activated protein kinase (p38MAPK)/heat shock protein beta-1 (HSPB1) pathway were examined. The results showed that Se-Met increased GPX1 expression (NE-S vs. NE-C: 2.28-fold; HE-S vs. HE-C: 2.36-fold, p < 0.05) and alleviated heat-induced decrease in cell viability (HE-S vs. HE-C: 1.41-fold; HE-C vs. NE-C: 0.61-fold, p < 0.01), although the viability was still lower than that in the NE-C cells (HE-S vs. NE-C: 0.85-fold) and Se-Met-treated cells (HE-S vs. NE-S: 0.81-fold). Se-Met relieved heat-induced decrease in testosterone level (HE-S vs. HE-C: 1.84-fold, p < 0.05) and HSD3B expression (HE-S vs. HE-C: 1.67-fold, p < 0.05). Se-Met alleviated heat-induced increase in Bcl2-associated protein X (BAX) expression (HE-C vs. HE-S: 2.4-fold, p < 0.05), and decrease in B-cell lymphoma-2 (BCL2) expression (HE-S vs. HE-C: 2.62-fold, p < 0.05), resulting in increased BCL2/BAX ratio in the HE-S cells (HE-S vs. HE-C: 5.24-fold, p < 0.05). Furthermore, Se-Met alleviated heat-induced activation of p-p38MAPK/p38MAPK (HE-C vs. HE-S: 1.79-fold, p < 0.05) and p-HSPB1/HSPB1 (HE-C vs. HE-S: 2.72-fold, p < 0.05). In conclusion, p38MAPK/HSPB1 might be involved in Se-Met-mediated alleviation of heat-induced cell apoptosis, cell viability and testosterone secretion impairments in sheep LCs.

Co-exposure of decabromodiphenyl ethane and cadmium increases toxicity to earthworms: Enrichment, oxidative stress, damage and molecular binding mechanisms

The increase of electronic waste worldwide has resulted in the exacerbation of combined decabromodiphenyl ethane (DBDPE) and cadmium (Cd) pollution in soil, posing a serious threat to the safety of soil organisms. However, whether combined exposure increases toxicity remains unclear. Therefore, this study primarily investigated the toxic effects of DBDPE and Cd on earthworms at the individual, tissue, and cellular levels under single and combined exposure. The results showed that the combined exposure significantly increased the enrichment of Cd in earthworms by 50.32-90.42 %. The toxicity to earthworms increased with co-exposure, primarily resulting in enhanced oxidative stress, inhibition of growth and reproduction, intensified intestinal and epidermal damage, and amplified coelomocyte apoptosis. PLS-PM analysis revealed a significant and direct relationship between the accumulation of target pollutants in earthworms and oxidative stress, damage, as well as growth and reproduction of earthworms. Furthermore, IBR analysis indicated that SOD and POD were sensitive biomarkers in earthworms. Molecular docking elucidated that DBDPE and Cd induced oxidative stress responses in earthworms through the alteration of the conformation of the two enzymes. This study enhances understanding of the mechanisms behind the toxicity of combined pollution and provides important insights for assessing e-waste contaminated soils.

Cross-Talk Between Selenium Nanoparticles and Cancer Treatment Through Autophagy

Autophagy is commonly referred as self-eating and a complex cellular process that is involved in the digestion of protein and damaged organelles through a lysosome-dependent mechanism, and this mechanism is essential for maintaining proper cellular homeostasis. Selenium is a vital trace element that plays essential functions in antioxidant defense, redox state control, and range of particular metabolic processes. Selenium nanoparticles have become known as a promising agent for biomedical use, because of their high bioavailability, low toxicity, and degradability. However, and in recent years, they have attracted the interest of researchers in developing anticancer nano-drugs. Selenium nanoparticles can be used as a potential therapeutic agent or in combination with other agents to act as carriers for the development of new treatments. More intriguingly, selenium nanoparticles have been extensively shown to impact autophagy signaling, allowing selenium nanoparticles to be used as possible cancer treatment agents. This review explored the connections between selenium and autophagy, followed by developments and current advances of selenium nanoparticles for autophagy control in various clinical circumstances. Furthermore, this study examined the functions and possible processes of selenium nanoparticles in autophagy regulation, which may help us understand how selenium nanoparticles regulate autophagy for the potential cancer treatment.

Decreased eggshell strength caused by impairment of uterine calcium transport coincide with higher bone minerals and quality in aged laying hens

BACKGROUND

Deteriorations in eggshell and bone quality are major challenges in aged laying hens. This study compared the differences of eggshell quality, bone parameters and their correlations as well as uterine physiological characteristics and the bone remodeling processes of hens laying eggs of different eggshell breaking strength to explore the mechanism of eggshell and bone quality reduction and their interaction. A total of 240 74-week-old Hy-line Brown laying hens were selected and allocated to a high (HBS, 44.83 ± 1.31 N) or low (LBS, 24.43 ± 0.57 N) eggshell breaking strength group.

RESULTS

A decreased thickness, weight and weight ratio of eggshells were observed in the LBS, accompanied with ultrastructural deterioration and total Ca reduction. Bone quality was negatively correlated with eggshell quality, marked with enhanced structures and increased components in the LBS. In the LBS, the mammillary knobs and effective layer grew slowly. At the initiation stage of eggshell calcification, a total of 130 differentially expressed genes (DEGs, 122 upregulated and 8 downregulated) were identified in the uterus of hens in the LBS relative to those in the HBS. These DEGs were relevant to apoptosis due to the cellular Ca overload. Higher values of p62 protein level, caspase-8 activity, Bax protein expression and lower values of Bcl protein expression and Bcl/Bax ratio were seen in the LBS. TUNEL assay and hematoxylin-eosin staining showed a significant increase in TUNEL-positive cells and tissue damages in the uterus of the LBS. Although few DEGs were identified at the growth stage, similar uterine tissue damages were also observed in the LBS. The expressions of runt-related transcription factor 2 and osteocalcin were upregulated in humeri of the LBS. Enlarged diameter and more structural damages of endocortical bones and decreased ash were observed in femurs of the HBS.

CONCLUSION

The lower eggshell breaking strength may be attributed to a declined Ca transport due to uterine tissue damages, which could affect eggshell calcification and lead to a weak ultrastructure. Impaired uterine Ca transport may result in reduced femoral bone resorption and increased humeral bone formation to maintain a higher mineral and bone quality in the LBS.

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.

Trends and recent progresses of selenium nanoparticles as novel autophagy regulators for therapeutic development

Autophagy, one of the major intracellular degradation systems, plays an important role in maintaining normal cellular physiological functions and protecting organisms from different diseases. Selenium (Se), an essential trace element, is involved in many metabolic regulatory signaling events and plays a key role in human health. In recent years, selenium nanoparticles (Se NPs) have attracted increasing attentions in biomedical field due to their low toxicity, high bioavailability and high bioactivity. Taking the advantage of their advanced biological activities, Se NPs can be used alone as potential therapeutic agents, or combine with other agents and served as carriers for the development of novel therapeutics. More interestingly, Se NPs have been widely reported to affect autophagy signaling, which therefor allow Se NPs to be used as potential therapeutic agents against different diseases. Here, this review suggested the relationships between Se and autophagy, followed by the trends and recent progresses of Se NPs for autophagy regulation in different diseased conditions. More importantly, this work discussed the roles and potential mechanisms of Se NPs in autophagy regulating, which might enhance our understanding about how Se NPs regulate autophagy for potential disease treatment. This work is expected to promote the potential application of Se NPs as novel autophagy regulators, which might benefit the development of novel autophagy associated therapeutics.

Dietary curcumin supplementation relieves hydrogen peroxide-induced testicular injury by antioxidant and anti-apoptotic effects in roosters

This study was aimed to investigate the effects of dietary curcumin supplementation on the hydrogen peroxide (H₂O₂)-induced testicular oxidative damage in breeder roosters. Thirty-two 20-week roosters were randomly divided into four groups: (1) basal diet (CON); (2) basal diet with H₂O₂ challenge (H₂O₂); (3) basal diet with 200 mg/kg curcumin (CUR); (4) basal diet with 200 mg/kg curcumin and H₂O₂ challenge (CUR + H₂O₂). The trial lasted for 8 weeks, H₂O₂ challenged groups got an intraperitoneal injection of H₂O₂ at the 50 and 53 days, while the CON and CUR groups received an injection of saline. The results showed that dietary curcumin supplementation significantly decreased abnormal sperm rates in the semen, notably improved seminiferous tubules, increased testis scores, and serum testosterone levels. Curcumin supplementation could also ameliorate the redox damage caused by H₂O₂, by enhancing the capacities of antioxidant enzymes (CAT, GSH-Px, SOD, and T-AOC), and reducing MDA levels. In addition, curcumin normalized the H₂O₂-induced negative effects, which included downregulations in spermatogenesis-related genes (STAR, HSD3-β1, SYCP3, AKT1) and antioxidant genes (HMOX-1, NQO-1), reduced protein expressions of Nrf2, PCNA, and Bcl-2, and increased protein expressions of Caspase 3 and Bax. Moreover, H₂O₂-induced decreased mRNA expressions of EIF2AK3, Caspase3, and BCL-2 were all reversed by dietary curcumin supplementation. In summary, dietary curcumin supplementation could relieve H₂O₂-induced oxidative damage and reproduction decline through the Nrf2 signaling pathway and anti-apoptotic effects in roosters.

The Roles of Histone Modifications in Metal-Induced Neurological Disorders

Increasing research is illuminating the intricate roles of metal ions in neural development as well as neurological disorders, which may stem from misregulation or dysfunction of epigenetic modifiers. Lead (Pb), cadmium (Cd), aluminum (Al), and arsenic were chosen for critical review because they have become serious public health concerns due to globalization and industrialization. In this review, we will introduce various modes of action of metals and consider the role of two posttranslational modifications: histone acetylation and methylation and how each of them affects gene expression. We then summarize the findings from previous studies on the neurological outcomes and histone alterations in response to the metals on each of the previously described histone modifications mechanisms. Understanding metal-induced histone modifications changes could provide better insight on the mechanism through which neurotoxicity occurs, to propose and validate these modifications as possible biomarkers for early identification of neurological damage, and can help model targeted therapies for the diseases of the brain.

Selenium regulates Nrf2 signaling to prevent hepatotoxicity induced by hexavalent chromium in broilers

Hexavalent chromium (Cr(Ⅵ)) is considered to be a common environmental pollutant, which widely exists in industrial effluents and wastes and then potentially noxious effects to the health of the poultry. Studies have reported that selenium (Se), which is one of the essential trace elements of the poultry and participates in the oxidative metabolism, can alleviate Cr(Ⅵ)-induced organ damage by inhibiting oxidative stress, but its specific molecular mechanism remains unclear. Herein, animal models of Cr(Ⅵ)- and Se-exposure were constructed using broilers to investigate the antagonistic mechanism of Se to Cr(Ⅵ)-induced hepatotoxicity. In this experiment, the four groups of broiler models were used as the research objects: control, Se, Se plus Cr, and Cr groups. Histopathology and ultrastructure liver changes were observed. Liver-somatic index, serum biochemistry, oxidative stress, Nrf2 pathway related factors, and autophagy-related genes were also determined. Overall, Se was found to ameliorate the disorganized structure, hepatic insufficiency, and oxidative damage caused by Cr(Ⅵ) exposure. Electron microscopy analysis further showed that the number of autophagosomes was obviously decreased after Se treatment compared to Cr group. Furthermore, gene and protein expression analyses illustrated that the levels of Nrf2, glutathione peroxidase 1 (GPx-1), NAD(P)H: quinone oxidoreductase 1 (NQO1), and mechanistic target of rapamycin (mTOR) in the Se&Cr group was upregulated, along with decreased expression of Beclin 1, ATG5 and LC3 compared to the Cr group. These suggest that Se can repair the oxidative lesion and autophagy induced by Cr(Ⅵ) exposure in broiler livers by upregulating the Nrf2 signaling pathway.

The Selenium Yeast vs Selenium Methionine on Cell Viability, Selenoprotein Profile and Redox Status via JNK/ P38 Pathway in Porcine Mammary Epithelial Cells

Comprehensive studies have been conducted to compare the effect of organic and inorganic selenium previously, but there is still limited knowledge about the difference between organic selenium (Se) from varied sources despite the widely use of organic Se in both animal and human being nutrient additives. In the present study, we systemically compared the effect of two different types of organic Se including selenium yeast (SeY) and selenium methionine (Sel-Met) on cell viability, selenoprotein transcriptome, and antioxidant status in porcine mammary epithelial cells (PMECs) and the results indicated that appropriate addition of SeY and Sel-Met both significantly promoted cell viability and up-regulated the mRNA expression of most selenopreoteins including DIOs, GPXs, and TrxRs family et al. (P < 0.05). Besides, two different sources of Se supplementation both greatly improved redox status with higher levels of T-AOC, SOD, and CAT (P < 0.05), while less content of MDA (P < 0.05), and reduced protein expression of cleaved-caspase-3 (P < 0.05) to mitigate cell apoptosis. Furthermore, the key proteins related to p38/JNK pathway including p38, p-p38, JNK, and p-JNK were apparently reduced in the groups with both of SeY and Sel-Met (P < 0.05). Interestingly we found that the changes induced by SeY supplementation in cell viability, selenoprotein transcriptome, antioxidative capacity, and anti-apoptosis were comprehensively greater compared with same levels addition of Sel-Met in PEMCs (P < 0.05). In conclusion, both SeY and Sel-Met promoted cell viability and attenuated cell apoptosis by regulating the selenoprotein expression and antioxidative capacity via p38/JNK signaling pathway in PMEC, but SeY has more efficient benefits than that of Sel-Met.