Toward improved human health: efficacy of dietary selenium on immunity at the cellular level.

Selenium, an essential trace element in the body, participates in various biological processes in the form of selenoproteins. In humans, a suitable concentration of selenium is essential for maintaining normal cellular function. Decreased levels of selenoproteins can lead to obstruction of the normal physiological functions of tissues and cells and even death. In addition, the level of selenium in the body affects cellular immunity, humoral immunity, and the balance between type 2 and type 1 helper T cells. Selenium can affect the immune function of the body through the reactive oxygen species (ROS), NF-κB, ferroptosis and NRF2 pathways. This paper reviews the immune effect of selenium on the body and the process of signal transduction and aims to serve as a reference for follow-up studies of immune function and research on the development of new selenium compounds and active targets.

Increased antitumor efficacy of ginsenoside Rh2 via mixed micelles: in vivo and in vitro evaluation.

The aim of this work is to apply Solutol® HS15 and TPGS to prepare self-assembled micelles loading with ginsenoside Rh2 to increase the solubility of ginsenoside Rh2, hence, improving the antitumor efficacy. Ginsenoside Rh2-mixed micelles (Rh2-M) were prepared by thin film dispersion method. The optimal Rh2-M was characterized by particle size, morphology, and drug encapsulation efficiency. The enhancement of in vivo anti-tumor efficacy of Rh2-M was evaluated by nude mice bearing tumor model. The solubility of Rh2 in self-assembled micelles was increased approximately 150-folds compared to free Rh2. In vitro results demonstrated that the particle size of Rh2-M is 74.72 ± 2.63 nm(PDI = 0.147 ± 0.15), and the morphology of Rh2-M is spherical or spheroid, and the EE% and LE% are 95.27 ± 1.26% and 7.68 ± 1.34%, respectively. The results of in vitro cell uptake and in vivo imaging showed that Rh2-M could not only increase the cell uptake of drugs, but also transport drug to tumor sites, prolonging the retention time. In vitro cytotoxicity and in vivo antitumor results showed that the anti-tumor effect of Rh2 can be effectively improved by Rh2-M. Therefore, Solutol® HS15 and TPGS could be used to entrapping Rh2 into micelles, enhancing solubility and antitumor efficacy.

IFN-γ Activates the TLR4-CCL5 Signaling Through Reducing Arginine Level, Leading to Enhanced Susceptibility of Bovine Mammary Epithelial Cells to Staphylococcus aureus.

Dairy cow mastitis is a common bacterial infectious disease which seriously threatens the development of the dairy cow industry. Previous studies have found that increased IFN-γ expression in dairy cows makes dairy cows more susceptible to mastitis, but the underlying mechanism is still not known. In this study, we utilized the in vitro bovine mammary epithelial cells (BMECs) model to explore the molecular mechanism via transcriptome sequencing technology, immunofluorescence, and Western blotting. It was found that IFN-γ promoted the adhesion and invasion of Staphylococcus aureus to BMECs through increasing the expression of TLR4-mediated CCL5 in BMECs. IFN-γ increased the activity of arginase II and reduced the level of arginine in cells, while the addition of arginine inhibited the expression of TLR4 and CCL5. An invasion experiment in mice further validated that IFN-γ treatment significantly increased the bacterial load in mammary glands and blood. However, the colonization and diffusion of S. aureus were interestingly decreased after Arg supplement. These data reveal that increased IFN-γ reduces arginine levels and activates TLR4-CCL5 signaling, leading to enhanced susceptibility of BMECs to S. aureus. Our findings are helpful to understand the pathogenesis of dairy cow mastitis and provide a theoretical basis for improvement of mastitis resistance in dairy cows.

Involvement of eIF2α in halofuginone-driven inhibition of TGF-ß1-induced EMT.

Halofuginone (HF) is an extract from the widely used traditional Chinese medicine (TCM) Dichroa febrifuga that facilitates the recovery of wounds and attenuates hepatic fibrosis. However, the role of HF in the epithelial-mesenchymal transition (EMT) of IPEC-J2 cells remains unclear. The current study explored the anti-EMT effect of HF in IPEC-J2 cells and illustrates its molecular mechanism. Transforming growth factor ß1 (TGF-ß1), as a recognized profibrogenic cytokine, decreased the level of the epithelial marker E-cadherin and increased the level of the mesenchymal markers, such as N-cadherin, fibronectin (FN), vimentin (Vim), and α-smooth muscle actin (α-SMA), in IPEC-J2 cells depending on the exposure time and dose. HF markedly prevented the EMT induced by TGF-ß1. Dissection of the mechanism revealed that HF inhibited IPEC-J2 cell EMT via modulating the phosphorylation of SMAD2/3 and the SMAD2/3-SMAD4 complex nuclear translocation. Furthermore, HF could promote the phosphorylation of eukaryotic translation initiation factor-2α (eIF2α), which modulates the SMAD signaling pathway. These results suggested that HF inhibits TGF-ß1-induced EMT in IPEC-J2 cells through the eIF2α/SMAD signaling pathway. Our findings suggest that HF can serve as a potential anti-EMT agent in intestinal fibrosis therapy.

miR-31 shuttled by halofuginone-induced exosomes suppresses MFC-7 cell proliferation by modulating the HDAC2/cell cycle signaling axis.

Traditional Chinese medicine (TCM) are both historically important therapeutic agents and important source of new drugs. Halofuginone (HF), a small molecule alkaloid derived from febrifugine, has been shown to exert strong antiproliferative effects that differ markedly among various cell lines. However, whether HF inhibits MCF-7 cell growth in vitro and underlying mechanisms of this process are not yet clear. Here, we offer the strong evidence of the connection between HF treatment, exosome production and proliferation of MCF-7 cells. Our results showed that HF inhibits MCF-7 cell growth in both time- and dose-dependent manner. Further microRNA (miRNA) profiles analysis in HF treated and nontreated MCF-7 cell and exosomes observed that six miRNAs are particularly abundant and sorted in exosomes. miRNAs knockdown experiment in exosomes and the MCF-7 growth inhibition assay showed that exosomal microRNA-31 (miR-31) modulates MCF-7 cells growth by specially targeting the histone deacetylase 2 (HDAC2), which increases the levels of cyclin-dependent kinases 2 (CDK2) and cyclin D1 and suppresses the expression of p21. In conclusion, these data indicate that inhibition of exosome production reduces exosomal miR-31, which targets the HDAC2 and further regulates the level of cell cycle regulatory proteins, contributing to the anticancer functions of HF. Our data suggest a new role for HF and the exosome production in tumorigenesis and may provide novel insights into prevention and treatment of breast cancer.

Arginine inhibits the malignant transformation induced by interferon-gamma through the NF-κB-GCN2/eIF2α signaling pathway in mammary epithelial cells in vitro and in vivo.

Breast cancer is the most common female malignant tumors in the world. It seriously affects women's physical and mental health and the leading cause of cancer death among women. Our previous study demonstrated that diet-derived IFN-γ promoted the malignant transformation of primary bovine mammary epithelial cells by accelerating arginine depletion. The current study aimed to explore whether arginine addition could inhibit the degree of malignant transformation and its molecular mechanism. The results indicate that arginine addition could alleviate the malignant transformation of mammary epithelial cells induced by IFN-γ, including reducing cell proliferation, cell migration and colony formation, through the NF-κB-GCN2/eIF2α pathway. The in vivo experiments also consistently confirmed that arginine supplementation could significantly inhibit tumor growth in tumor-bearing mice. Furthermore, the investigation of the clinical data also revealed that the plasma or tissue from human breast cancer patients owned lower arginine level and higher IFN-γ level than that from patients with benign breast disease, showing IFN-γ may be a potential control target. Our findings demonstrate that arginine supplement could antagonize the malignant transformation of mammary epithelial cells induced by IFN-γ (nutritionally induced) both in vitro and in vivo, and IFN-γ was higher in breast cancer women. This might provide a novel strategy for the prevention and treatment of breast cancer regarding to nutrition.

Halofuginone-induced autophagy suppresses the migration and invasion of MCF-7 cells via regulation of STMN1 and p53.

Traditional Chinese medicines have been recognized as especially promising anticancer agents in modern anticancer research. Halofuginone (HF), an analog of quinazolinone alkaloid extracted from Dichroa febrifuga, is widely used in traditional medicine. However, whether HF inhibits the growth of breast cancer cells and/or reduces the migration and invasion of MCF-7 human breast cancer cells, as well as the underlying mechanisms in vitro, remains unclear. In this study, we report that an HF extract inhibits the growth of MCF-7 cells and reduces their migration and invasion, an important feature of potential anticancer agents. In addition, HF significantly increases the activation of autophagy, which is closely associated with tumor metastasis. As STMN1 and p53 have been closely implicated in breast cancer progression, we analyzed their expression in the context of HF extract treatment. Western blot analysis showed that HF suppresses STMN1 and p53 expression and activity in an autophagy-dependent manner. Collectively, these data indicate that activation of autophagy reduces expression of STMN1 and p53, and the migration and invasion of cancer cells contributes to the anti-cancer effects of the HF. These findings may provide new insight into breast cancer prevention and therapy.

Arginine Supplementation Recovered the IFN-γ-Mediated Decrease in Milk Protein and Fat Synthesis by Inhibiting the GCN2/eIF2α Pathway, Which Induces Autophagy in Primary Bovine Mammary Epithelial Cells.

During the lactation cycle of the bovine mammary gland, autophagy is induced in bovine mammary epithelial cells (BMECs) as a cellular homeostasis and survival mechanism. Interferon gamma (IFN-γ) is an important antiproliferative and apoptogenic factor that has been shown to induce autophagy in multiple cell lines in vitro. However, it remains unclear whether IFN-γ can induce autophagy and whether autophagy affects milk synthesis in BMECs. To understand whether IFN-γ affects milk synthesis, we isolated and purified primary BMECs and investigated the effect of IFN-γ on milk synthesis in primary BMECs in vitro. The results showed that IFN-γ significantly inhibits milk synthesis and that autophagy was clearly induced in primary BMECs in vitro within 24 h. Interestingly, autophagy was observed following IFN-γ treatment, and the inhibition of autophagy can improve milk protein and milk fat synthesis. Conversely, upregulation of autophagy decreased milk synthesis. Furthermore, mechanistic analysis confirmed that IFN-γ mediated autophagy by depleting arginine and inhibiting the general control nonderepressible-2 kinase (GCN2)/eukaryotic initiation factor 2α (eIF2α) signaling pathway in BMECs. Then, it was found that arginine supplementation could attenuate IFN-γ-induced autophagy and recover milk synthesis to some extent. These findings may not only provide a novel measure for preventing the IFN-γ-induced decrease in milk quality but also a useful therapeutic approach for IFN-γ-associated breast diseases in other animals and humans.