Selenium-Containing Protein From Selenium-Enriched Spirulina platensis Attenuates High Glucose-Induced Calcification of MOVAS Cells by Inhibiting ROS-Mediated DNA Damage and Regulating MAPK and PI3K/AKT Pathways

The Role of Selenium in Atherosclerosis Development, Progression, Prevention and Treatment

Selenium is an essential trace element that is essential for various metabolic processes, protection from oxidative stress and proper functioning of the cardiovascular system. Se deficiency has long been associated with multiple cardiovascular diseases, including endemic Keshan's disease, common heart failure, coronary heart disease, myocardial infarction and atherosclerosis. Through selenoenzymes and selenoproteins, Se is involved in numerous crucial processes, such as redox homeostasis regulation, oxidative stress, calcium flux and thyroid hormone metabolism; an unbalanced Se supply may disrupt these processes. In this review, we focus on the importance of Se in cardiovascular health and provide updated information on the role of Se in specific processes involved in the development and pathogenesis of atherosclerosis (oxidative stress, inflammation, endothelial dysfunction, vascular calcification and vascular cell apoptosis). We also discuss recent randomised trials investigating Se supplementation as a potential therapeutic and preventive agent for atherosclerosis treatment.

Monoclonal antibody based immunoassay: An alternative way for aquatic environmental selenium detection

Environmental concerns about human health encouraged increasing methodological interest in selenium (Se), which is an essential non-metal trace element and varies within a narrow concentration range between essential and toxic. In this study, two types of long-armed Se haptens (Se-hapten-lc-NHS) were synthesized for the first time using active ester formalization. In producing monoclonal antibodies (mAbs), the derivatization of haptenized Se at para- (meta-) and ortho-sites showed different properties. Finally, a mAb derived from hybridoma 5A5² was confirmed to be capable of establishing an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). There was a successful quantitative determination of Se⁴⁺ with a detection range of 17 to 207 pmol mL^-1 and a limit of detection of approximately 3.9 pmol mL^-1. The mAb was found to be remarkably sensitive and specific, with no evidence of cross-reactivity with other ions. The assay was validated for four kinds of Se forms in water samples and showed satisfactory recoveries between 80 % and 108 %, with coefficients of variation of 2.1 %-11 %. The method proposed in our study offers a useful protocol for the rapid screening of Se and provides an alternative solution for the analysis of Se in aquatic environments.

Deletion of SIRT6 in vascular smooth muscle cells facilitates vascular calcification via suppression of DNA damage repair

Vascular calcification is an important risk factor for cardiovascular events, accompanied by DNA damage during the process. The sirtuin 6 (SIRT6) has been reported to alleviate atherosclerosis, which is related to the reduction of DNA damage. However, whether smooth muscle cell SIRT6 mediates vascular calcification involving DNA damage remains unclear. Western blot and immunofluorescence revealed that SIRT6 expression was decreased in human vascular smooth muscle cells (HVSMCs), human and mouse arteries during vascular calcification. Alizarin red staining and calcium content assay showed that knockdown or deletion of SIRT6 significantly promoted HVSMC calcification induced by high phosphorus and calcium, accompanied by upregulation of osteogenic differentiation markers including Runx2 and BMP2. By contrast, adenovirus-mediated SIRT6 overexpression attenuated osteogenic differentiation and calcification of HVSMCs. Moreover, ex vivo study revealed that SIRT6 overexpression inhibited calcification of mouse and human arterial rings. Of note, smooth muscle cell-specific knockout of SIRT6 markedly aggravated Vitamin D₃-induced aortic calcification in mice. Mechanistically, overexpression of SIRT6 reduced DNA damage and upregulated p-ATM during HVSMCs calcification, whereas knockdown of SIRT6 showed the opposite effects. Knockdown of ATM in HVSMCs abrogated the inhibitory effect of SIRT6 overexpression on calcification and DNA damage. This study for the first time demonstrates that vascular smooth muscle cell-specific deletion of SIRT6 facilitates vascular calcification via suppression of DNA damage repair. Therefore, modulation of SIRT6 and DNA damage repair may represent a therapeutic strategy for vascular calcification.

Antioxidant effects of Se-glutathione peroxidase in alcoholic liver disease

Oxidative damage induced by ethanol and its metabolites is one of the factors that fuels the development of alcoholic liver disease (ALD). Selenium (Se) is an effective cofactor for glutathione peroxidase (GPx), and has antioxidant effects that improve ALD. In patients with ALD, ethanol-induced oxidative damage inhibits the synthesis of related Se-containing proteins such as: selenoprotein P (Sepp1), albumin (ALB), and GPx in the liver, thus decreasing the overall Se level in patients. Both Se deficiency and excess can affect the expression of GPx, resulting in damage to the antioxidant defense system. This damage enhances oxidative stress by increasing the levels of reactive oxygen species (ROS) in the body, which aggravates the inflammatory response, lipid metabolism disorder, and lipid peroxidation and worsens ALD symptoms. A cascade of oxidative damages caused by ALD will deplete selenium deposition in the body, stimulate the expression of Gpx1, Sepp1, and Gpx4, and thus mobilize systemic selenoproteins, which can restore GPx activity in the hepatocytes of ALD patients, reduce the levels of reactive oxygen species and alleviate oxidative stress, the inflammatory response, lipid metabolism disorder, and lipid peroxidation, thus helping to mitigate ALD. This review provides a reference for future ALD studies that evaluate the regulation of Se levels and contributes to studies on the potential pathological mechanisms of Se imbalance in ALD.

A review on selenium-enriched proteins: preparation, purification, identification, bioavailability, bioactivities and application

Selenium (Se) deficiency can cause many diseases and thereby affect human health. Traditional inorganic Se supplements have disadvantages of toxicity and low bioavailability. Se-Enriched proteins exhibit good bio-accessibility and high biological activities. This review provides a comprehensive overview of the preparation, purification, identification, bioavailability, bioactivities and application of Se-enriched proteins. The method of extracting Se-enriched proteins from animals, microorganisms and plants mainly includes solvent extraction (water, salt, ethanol and alkali solution extraction) and novel extraction technologies (ultrasound-assisted and pulsed electric field assisted extraction). Se-Enriched proteins and their hydrolysates exhibit good bioactivities, mainly including antioxidant activity, immune regulation, neuroprotective activity, and inhibition of hyperglycemic activity, among others. Future research should focus on the relationship between Se-enriched protein metabolism and the selenium regulatory protein metabolic pathway by using multi-omics technology. In addition, it is necessary to comprehensively study the structure-activity relationship of Se-enriched proteins/hydrolysates from different sources, to further clarify their bioactive mechanism and to verify their health benefits in vivo.