Selenomethionine Suppressed TLR4/NF-κB Pathway by Activating Selenoprotein S to Alleviate ESBL Escherichia coli-Induced Inflammation in Bovine Mammary Epithelial Cells and Macrophages

Wenshenqianlie capsule improves benign prostatic hyperplasia via its anti-inflammatory and antioxidant effects

Anti-inflammatory and antioxidant effects play crucial roles in the recovery of benign prostatic hyperplasia (BPH). Wenshenqianlie (WSQL) capsule, a typical traditional Chinese medicine formulation combining 14 Chinese herbs, has been reported to exert tonic effects on the kidneys and improve clinical symptoms of BPH. However, its potential antioxidative and anti-inflammatory properties and effects on the improvement of hormone levels have not been reported in depth. In this study, mice were subcutaneously injected with TP (5 mg/kg·d-1) to induce BPH. Forty-eight adult BALB/c male mice were randomly allocated to six groups based on the type of drug administered by gavage: control, BPH, BPH+WSQL (40 and 80 mg/kg·d-1), BPH+finasteride (1 mg/kg·d-1), and WSQL-only treated (80 mg/kg·d-1). We investigated the anti-inflammatory and antioxidant effect and mechanism of WSQL on BPH via histopathological examination, immunohistochemistry, enzyme-linked immunosorbent assay, and western blotting combined with in vivo serum metabolomics, gut microbiomics analysis. WSQL alleviated prostate hyperplasia and reduced prostate-specific antigen, dihydrotestosterone, testosterone, and inflammation levels. Gut microbiomics and serum non-targeted metabolomics determined that the protective effect of WSQL against BPH may be related to the improvement of inflammation and testosterone-related gut microbiota and serum metabolites. Further studies showed that WSQL ameliorated nuclear factor-kappa B, its downstream inflammatory factors, and nuclear factor E2-related factor 2 pathway.

Development potential of selenium in the prevention and treatment of bovine endometritis

Endometritis is a common postpartum disease in cows. It delays uterine involution and impairs normal physiological function. This can result in long-term or even lifelong infertility and cause significant losses to the dairy farming industry. Traditional treatments like antibiotics possess certain shortcomings, such as antibiotic residues, the abuse of antibiotics, and increased antimicrobial resistance of pathogens. Alternative treatment strategies are needed to minimize the utilization of antibiotics in dairy production. As an essential trace element in animals, selenium (Se) plays a vital role in regulating immune function, the inflammatory response, and oxidative stress, affecting the speed and completeness of tissue repair. This paper reviewed previous studies to analyse the potential of Se in the prevention and treatment of bovine endometritis, aiming to provide a new direction to increase production capacity in the future.

Lycopene promoted M2 macrophage polarization via inhibition of NOTCH1-PI3K-mTOR-NF-κB-JMJD3-IRF4 pathway in response to Escherichia coli infection in J744A.1 cells

Escherichia coli (E. coli) can induce severe clinical bovine mastitis, which is to blame for large losses experienced by dairy farms. Macrophage polarization into various states is in response to pathogen infections. Lycopene, a naturally occurring hydrocarbon carotenoid, relieved inflammation by controlling M1/M2 status of macrophages. Thus, we wanted to explore the effect of lycopene on polarization states of macrophages in E. coli-induced mastitis. Macrophages were cultivated with lycopene for 24, before E. coli inoculation for 6 h. Lycopene (0.5 μmol/L) significantly enhanced cell viabilities and significantly reduced lactic dehydrogenase (LDH) levels in macrophages, whereas 2 and 3 μmol/L lycopene significantly enhanced LDH activities. Lycopene treatment significantly reduced the increase in LDH release, iNOS, CD86, TNF-α, IL-1β and phosphatase and tensin homolog (PTEN) expressions in E. coli group. 0.5 μmol/L lycopene significantly increased E. coli-induced downregulation of CD206, arginase I (ARG1), indoleamine 2,3-dioxygenase (IDO), chitinase 3-like 3 (YM1), PI3K, AKT, p-AKT, mammalian target of rapamycin (mTOR), p-mTOR, jumonji domain-containing protein-3 (JMJD3) and interferon regulatory factor 4 (IRF4) levels. Moreover, Ginkgolic acid C17:1 (a specific PTEN inhibitor), 740YPDGFR (a specific PI3K activator), SC79 (a specific AKT activator) or CHPG sodium salt (a specific NF-κB activator) significantly decreased CD206, AGR1, IDO and YM1 expressions in lycopene and E. coli-treated macrophages. Therefore, lycopene increased M2 macrophages via inhibiting NOTCH1-PI3K-mTOR-NF-κB-JMJD3-IRF4 pathway in response to E. coli infection in macrophages. These results contribute to revealing the pathogenesis of E. coli-caused bovine mastitis, providing the new angle of the prevention and management of mastitis.

Systemic and local responses of cytokines and tissue histology following intramammary lipopolysaccharide challenge in dairy cows

During bovine mastitis, immune responses include the release of cytokines and the recruitment of leukocytes, resulting in profound structural and functional changes in the mammary gland. Our aims were to delineate systemic and local cytokine responses and to quantify histological changes in the mammary tissue of lactating cows after acute intramammary lipopolysaccharide (LPS) challenge. Ten multiparous dairy cows were paired to either treatment (TRT) or control (CON) groups. For TRT cows, one side of the udder was randomly assigned to receive treatment with LPS (50 µg in 10 mL of saline, TL) into both the front and rear quarters; the contralateral quarters received saline (10 mL). Udder-halves of CON cows were similarly assigned randomly to receive either saline (10 mL, CS) or no infusion (untreated). Temporal changes in the concentrations of 15 cytokines in the blood (0, 3, 6, 12, and 24 h relative to the LPS infusion) and in mammary tissue (0, 3, and 12 h) were determined, as were concomitant changes in mammary histology. The cytokines IL-6, IL-10, MCP-1, and MIP-1β showed a systemic response as their concentrations were significantly different in the plasma of TRT cows as compared with CON cows after LPS challenge. The cytokines IL-1α, IL-1β, IL-6, IL-8, IL-17A, IL-36RA, IP-10, MCP-1, MIP-1α, MIP-1β, TNF-α, and VEGF-A showed a local response in TL glands, and 8 cytokines, IL-1β, IL-6, IL-10, IL-17A, IL-36RA, IP-10, MIP-1β, and VEGF-A showed systemic changes in the nonchallenged mammary glands adjacent to LPS-infused glands. Endotoxin challenge evoked changes in the histology of mammary tissue that included a 5.2- and 7.2-fold increases in the number of neutrophils in alveolar lumens at 3 h and 12 h, respectively. In summary, LPS challenge induced specific local and systemic responses in cytokine induction and elicited neutrophil infiltration in bovine mammary tissue.

Resveratrol attenuated high intensity exercise training-induced inflammation and ferroptosis via Nrf2/FTH1/GPX4 pathway in intestine of mice

BACKGROUND

Moderate exercise has beneficial effects for human health and is helpful for the protection against several diseases. However, high intensity exercise training caused gastrointestinal syndrome. Resveratrol, a plant extract, plays a vital role in protecting various organs. However, whether resveratrol protected mice against high intensity exercise training-induced intestinal damage remains unclear. In this study, our objective was to investigate the protective effects and mechanism of resveratrol in high intensity exercise training-treated mice.

METHODS

Mice were treated with swimming exercise protocol and/or resveratrol (15 mg/kg/day) for 28 consecutive days. Then, the mice were sacrificed, and a series of evaluation indicators, including inflammatory factors and intestinal permeability of the gut, were measured based on this model. The expressions of inflammatory factors (tumor necrosis factor (TNF)-α; interferon (IFN)-γ, interleukin (IL)-6 and IL-10), oxidative stress (Nrf2, glutathione (GSH), hydrogen peroxide (H2 O2), catalase (CAT) and malondialdehyde(MDA)), intestinal barrier (gut permeability, ZO-1, Occludin and Claudin-1 as well as ferroptosis (Fe2+, Fe3+, SLC7A11, glutathioneperoxidase 4 (GPX4) and ferritin heavy chain 1 (FTH1)) were measured, respectively.

RESULTS

High intensity exercise training induced colon damage, manifested as inflammation (increased TNF-α, IFN-γ and IL-6 concentrations, and decreased IL-10 concentration), oxidative stress (the increase of H2O2 and MDA concentration, and the reduced CAT and GSH activities), intestinal barrier injury (increased gut permeability and intestinal fatty-acid binding protein concentration,and inhibited ZO-1, Occludin and Claudin-1 expressions) and ferroptosis (the increased of Fe2+ and Fe3+ concentrations, and suppressed phosphorylated Nrf2, SLC7A11, GPX4 and FTH1), which was relieved by resveratrol treatment in mice.

DISCUSSION

Resveratrol attenuated high intensity exercise training-induced inflammation and ferroptosis through activating Nrf2/ FTH1/GPX4 pathway in mouse colon, which providing new ideas for the prevention and treatment of occupational disease in athlete.

Genetically engineered cell membrane-coated nanoparticles for antibacterial and immunoregulatory dual-function treatment of ligature-induced periodontitis

Purpose: In order to overcome the problem that conventional pharmacological treatments of periodontitis cannot effectively synergizing antimicrobial and immunomodulation, inspired by the critical role of toll-like receptor 4 (TLR4) in bacterial recognition and immune activation, we demonstrated a combined antibacterial-immunoregulatory strategy based on biomimetic nanoparticles. Methods: Functioned cell membranes and silk fibroin nanoparticles (SNs) loaded with minocycline hydrochloride (Mino) were used to prepare a biomimetic nanoparticle (MSNCs). SNs and MSNCs were characterized by Scanning Electron Microscope, size, zeta potential, dispersion index. At the same time, SNs were characterized by cell counting kit-8 and real-time Polymerase Chain Reaction (RT-PCR). TLR4-expressing cell membranes were characterized by RT-PCR and western blot (WB). Cell membrane coating was characterized by Transmission Electron Microscope (TEM), the Bradford staining and WB. Then, Laser confocal, flow cytometry and agar plate coating were evaluated in vitro with antibacterial effects, RT-PCR was simultaneously evaluated with immunoregulatory effects. Finally, Anti-inflammatory treatment of MSNCs was evaluated in a ligature-induced periodontitis (LIP) mouse model. Results: Successfully prepared cell membranes overexpressing TLR4 and constructed MSNCs. In vitro studies had shown that MSNCs effectively targeted bacteria via TLR4 and acted as molecular decoys to competitively neutralize lipopolysaccharide (LPS) in the microenvironment as well as inhibit inflammatory activation of macrophages. In vivo, MSNCs effectively attenuated periodontal tissue inflammation and alveolar bone loss in a LIP mouse model. Conclusion: MSNCs have good targeted antibacterial and immunoregulatory effects, and provide a new and effective strategy for the treatment of periodontitis and have good potential for application in various types of pathogenic bacterial infections.

A Novel TLR4-SYK Interaction Axis Plays an Essential Role in the Innate Immunity Response in Bovine Mammary Epithelial Cells

Mammary gland epithelium, as the first line of defense for bovine mammary gland immunity, is crucial in the process of mammary glands’ innate immunity, especially that of bovine mammary epithelial cells (bMECs). Our previous studies successfully marked SYK as an important candidate gene for mastitis traits via GWAS and preliminarily confirmed that SYK expression is down-regulated in bMECs with LPS (E. coli) stimulation, but its work mechanism is still unclear. In this study, for the first time, in vivo, TLR4 and SYK were colocalized and had a high correlation in mastitis mammary epithelium; protein−protein interaction results also confirmed that there was a direct interaction between them in mastitis tissue, suggesting that SYK participates in the immune regulation of the TLR4 cascade for bovine mastitis. In vitro, TLR4 also interacts with SYK in LPS (E. coli)-stimulated or GBS (S. agalactiae)-infected bMECs, respectively. Moreover, TLR4 mRNA expression and protein levels were little affected in bMECsSYK- with LPS stimulation or GBS infection, indicating that SYK is an important downstream element of the TLR4 cascade in bMECs. Interestingly, IL-1β, IL-8, NF-κB and NLRP3 expression in LPS-stimulated or GBS-infected bMECsSYK- were significantly higher than in the control group, while AKT1 expression was down-regulated, implying that SYK could inhibit the IL-1β, IL-8, NF-κB and NLRP3 expression and alleviate inflammation in bMECs with LPS and GBS. Taken together, our solid evidence supports that TLR4/SYK/NF-κB signal axis in bMECs regulates the innate immunity response to LPS or GBS.

Traditional and emerging Fusarium mycotoxins disrupt homeostasis of bovine mammary cells by altering cell permeability and innate immune function

High incidence of traditional and emerging Fusarium mycotoxins in cereal grains and silages can be a potential threat to feed safety and ruminants. Inadequate biodegradation of Fusarium mycotoxins by rumen microflora following ingestion of mycotoxin-contaminated feeds can lead to their circulatory transport to target tissues such as mammary gland. The bovine udder plays a pivotal role in maintaining milk yield and composition, thus, human health. However, toxic effects of Fusarium mycotoxins on bovine mammary gland are rarely studied. In this study, the bovine mammary epithelial cell line was used as an in-vitro model of bovine mammary epithelium to investigate effects of deoxynivalenol (DON), enniatin B (ENB) and beauvericin (BEA) on bovine mammary gland homeostasis. Results indicated that exposure to DON, ENB and BEA for 48 h significantly decreased cell viability in a concentration-dependent manner (P < 0.001). Exposure to DON at 0.39 μmol/L and BEA at 2.5 μmol/L for 48 h also decreased paracellular flux of FITC-40 kDa dextran (P < 0.05), whereas none of the mycotoxins affected transepithelial electrical resistance after 48 h exposure. The qPCR was performed for assessment of expression of gene coding tight junction (TJ) proteins, toll-like receptor 4 (TLR4) and cytokines after 4, 24 and 48 h of exposure. DON, ENB and BEA significantly upregulated the TJ protein zonula occludens-1, whereas markedly downregulated claudin 3 (P < 0.05). Exposure to DON at 1.35 μmol/L for 4 h significantly increased expression of occludin (P < 0.01). DON, ENB and BEA significant downregulated TLR4 (P < 0.05). In contrast, ENB markedly increased expression of cytokines interleukin-6 (IL-6) (P < 0.001), tumor necrosis factor α (TNF-a) (P < 0.05) and transforming growth factor-β (TGF-β) (P < 0.01). BEA significantly upregulated IL- 6 (P < 0.001) and TGF-β (P = 0.01), but downregulated TNF-α (P < 0.001). These results suggest that DON, ENB and BEA can disrupt mammary gland homeostasis by inducing cell death as well as altering its paracellular permeability and expression of genes involved in innate immune function.

The protective role of caffeic acid on bovine mammary epithelial cells and the inhibition of growth and biofilm formation of Gram-negative bacteria isolated from clinical mastitis milk

As a first-line barrier against bacterial infection of mammary tissues, bovine mammary epithelial cells (bMECs) are generally believed to be involved in the immune response due to exogenous stress. Due to the escalating crisis of antibiotic resistance, there is an urgent need for new strategies to combat pathogenic bacteria-infected bovine mastitis. In this study, isolated bMECs and Institute of Cancer Research (ICR) mice were used for Escherichia coli infection and caffeic acid (CA) pretreatment experiments in vitro and in vivo. The inhibitory effect of CA on bacterial growth and biofilm formation was also demonstrated with bacteria strains isolated from mastitis-infected milk. It was demonstrated that CA supplementation prohibits the growth of the predominant strains of bacteria isolated from clinical bovine mastitis milk samples. CA was found to disrupt the biofilm formation of E. coli B1 in a sub-minimum inhibitory concentration (sub-MIC) and inhibited the adherence property of E. coli on bMECs by decreasing the staining of bacteria on cell surfaces in vitro. In addition, CA was found to attenuate proinflammatory and oxidative responses in cells infected with E. coli. The pretreatment of bMECs with CA also restored altered lipid homeostasis caused by E. coli stimulation. The protective role of CA was further confirmed via the administration of CA in mice followed by representative Gram-negative bacterial infection. Collectively, these findings highlight the potential of CA to mediate Gram-negative infections and indicate that it has the potential to be developed as a novel antibacterial drug.

Ochratoxin A and Citrinin Differentially Modulate Bovine Mammary Epithelial Cell Permeability and Innate Immune Function

Frequent detection of mycotoxins ochratoxin A (OTA) and citrinin (CIT) in ruminant feed and feedstuff can be a potential threat to feed safety, animal performance and health. Ineffective biodegradation of these mycotoxins by rumen microflora following ingestion of contaminated feeds can lead to their circulatory transport to tissues such as mammary gland as the result of their biodistribution throughout the body. The bovine mammary epithelium plays a pivotal role in maintaining milk yield and composition and contributes to innate immune defense of the udder. The present study is the first to investigate individual effects of OTA and CIT on barrier and innate immune functions of the bovine mammary epithelium using a bovine mammary epithelial cell line (MAC-T). Results indicated that OTA and CIT exposure for 48 h significantly decreased cell viability in a concentration-dependent manner (p < 0.05). A decrease in transepithelial electrical resistance and increase in paracellular flux of FITC-40 kDa dextran was significantly induced by OTA treatment (p < 0.05), but not by CIT after 48 h exposure. qPCR was performed for assessment of expression of tight-junction proteins, Toll-like receptor 4 (TLR4) and cytokines after 4, 24 and 48 h of exposure. Both OTA and CIT markedly downregulated expression of claudin 3 and occludin (p < 0.05), whereas CIT did not affect zonula occludens-1 expression. Expression of TLR4 was significantly upregulated by OTA (p < 0.001) but downregulated by CIT (p < 0.05) at 48 h. Expression of IL-6, TNF-a and TGF-β was significantly upregulated by OTA (p < 0.05), whereas IL-6 and TGF-β expression was downregulated by CIT (p < 0.01). These results suggest that OTA and CIT could potentially differentially modulate barrier and innate immune functions of mammary epithelium. The present study not only throws light on the individual toxicity of each mycotoxin on bovine mammary epithelium but also lays the foundation for future studies on the combined effects of the two mycotoxins.

Selenium Deficiency Aggravates Heat Stress Pneumonia in Chickens by Disrupting the M1/M2 Balance

Selenium (Se) is an essential trace element found in the body. Se deficiency and M1/M2 imbalance are closely related to inflammation. Heat stress can decrease immune function and cause inflammation. In order to investigate whether Se deficiency can aggravate pneumonia caused by heat stress and the role of M1/M2 imbalance in the occurrence of pneumonia, 100 AA broilers were divided into two groups and fed the conventional diet (0.2 mg/kg Se) and the Se-deficient diet (0.03 mg/kg Se). After 40 days of feeding, the normal feeding group was randomly divided into a control group and a heat stress group. At the same time, the Se-deficient diet feeding group was randomly divided into a low Se group and a low Se heat stress group, with 25 chickens in each group. The model was established by exposure at 40℃. Six hours later, broilers were euthanized, and their lung tissues were collected. Hematoxylin and eosin staining, immunofluorescence, quantitative real-time PCR, and western blotting were used to detect lung histopathological changes and the expression of M1/M2 markers, nuclear receptor-κB (NF-κB) pathway genes, and heat shock proteins. Meanwhile, the activity and content of oxidative stress-related indices were also detected. We found that the expression of interleukin-1β, interleukin-6, interleukin-12, and tumor necrosis factor-α was upregulated and the expression of interleukin-2, interleukin-10, and interferon-γ was downregulated. Immunofluorescence showed that the expression of CD16 was increased, the expression of CD163 was weakened, and the M1/M2 imbalance was present. In addition, the NF-κB pathway was activated by the increased expressions of heat shock proteins and oxidative stress. There was an increase in malondialdehyde, nitric oxide, and inducible nitric oxide synthase content, while the activity of total antioxidant capacity, glutathione peroxidase, catalase, and superoxide dismutase decreased, and the expression of NF-κB and cyclooxygenase-2 increased. These results suggest that low Se induces M1/M2 imbalance through oxidative stress activation of the NF-κB pathway and aggravates lung tissue inflammation caused by heat stress. This study offers a theoretical basis for exploring the pathogenesis of various kinds of inflammation induced by Se deficiency from the perspective of M1/M2 and provides a reference for the prevention of such diseases.

Positive effects of selenium supplementation on selenoprotein S expression and cytokine status in a murine model of acute liver injury

BACKGROUND

It is a consensus that selenomethionine (SeMet) can protect liver from damage, but the immune mechanism of SeMet in acute liver injury (ALI) is still unclear. This study aims to investigate the protective effects of SeMet against ALI and to elucidate the possible immune mechanism.

METHODS

Firstly, the role of SeMet in CCl4-induced ALI mice was investigated through survival rate, serum ALT and AST, liver necrosis and apoptosis analysis. The expression and secretion of inflammatory cytokines and chemokines in the liver and serum of CCl4-induced ALI mice were analyzed by qRT-PCR and ELISA. Then the immune cell phenotypes were analyzed by flow cytometry and confocal imaging. In addition, MDSCs depletion, CXCL12/CXCR4 axis blocking and selenoprotein S (SELENOS) knockdown assays were used to reveal the immune mechanism of SeMet.

RESULTS

We found that SeMet prolonged survival rate, decreased the serum ALT and AST, alleviated liver necrosis and inhibited hepatocytes apoptosis. Prospective, SeMet decreased the expression of IL-6 and TNF-α, and increased the expression of IL-10. Interestingly, SeMet decreased the expression of MCP-1, while increased the expression of CXCL12. The immune analysis showed that SeMet decreased the activation of T cells through promoting MDSCs accumulation mediated by CXCL12/CXCR4 axis. Furthermore, SeMet increased SELENOS expression in vivo, and knockdown of SELENOS effectively abolished the protective effect of SeMet during ALI.

CONCLUSION

This study demonstrates that SeMet alleviates CCl4-induced ALI by promoting MDSCs accumulation through SELENOS mediated CXCL12/CXCR4 axis. Therefore, our study infers that selenium intake may be as a new therapeutic option for management of inflammation-mediated liver injury.

Immunomodulatory and Anti-Inflammatory Properties of Selenium-Containing Agents: Their Role in the Regulation of Defense Mechanisms against COVID-19

The review presents the latest data on the role of selenium-containing agents in the regulation of diseases of the immune system. We mainly considered the contributions of selenium-containing compounds such as sodium selenite, methylseleninic acid, selenomethionine, and methylselenocysteine, as well as selenoproteins and selenium nanoparticles in the regulation of defense mechanisms against various viral infections, including coronavirus infection (COVID-19). A complete description of the available data for each of the above selenium compounds and the mechanisms underlying the regulation of immune processes with the active participation of these selenium agents, as well as their therapeutic and pharmacological potential, is presented. The main purpose of this review is to systematize the available information, supplemented by data obtained in our laboratory, on the important role of selenium compounds in all of these processes. In addition, the presented information makes it possible to understand the key differences in the mechanisms of action of these compounds, depending on their chemical and physical properties, which is important for obtaining a holistic picture and prospects for creating drugs based on them.

Selenium and Taurine Combination Is Better Than Alone in Protecting Lipopolysaccharide-Induced Mammary Inflammatory Lesions via Activating PI3K/Akt/mTOR Signaling Pathway by Scavenging Intracellular ROS

Mastitis is mainly induced by gram-negative bacterial infections, causing devastating economic losses to the global cattle industry. Both selenium (Se) and taurine (Tau) exhibit multiple biological effects, including reducing inflammation. However, no studies have reported the protective effect of the combined use of Se and Tau against mastitis, and the underlying mechanisms remain unclear. In this study, lipopolysaccharide (LPS), the vital virulence factor of gram-negative bacteria, was used to construct the in vivo and vitro mastitis models. The results of in vivo model showed that Se and Tau combination was more effective than either substance alone in reducing tissue hyperemia, edema, and neutrophil infiltration in the mammary acinar cavity, improving the blood-milk barrier in LPS-induced mice mastitis, and decreasing the expression of proinflammatory factors and the activity of MPO. Moreover, Se and Tau combination significantly increased the levels of LPS-induced reduction in PI3K/Akt/mTOR, but the expressions of TLRs and NLRP3 were not significantly changed in the mammary tissue. In the in vitro experiments, the effects of Se and Tau combination or alone on inflammatory factors, inflammatory mediators, MPO activity, and blood-milk barrier were consistent with those in vivo. The Se and Tau combination has also been found to increase the survival rate of BMECs compared with each substance alone via promoting cellular proliferation and inhibiting apoptosis. Also, it has been confirmed that this combination could restore the LPS-induced inhibition in the PI3K/Akt/mTOR signaling pathway. Inhibition of mTOR by Rapamycin counteracted the combined protection of SeMet and Tau against LPS-induced inflammatory damage, the inhibition of PI3K by LY294002 blocked the activation of mTOR, and the accumulation of ROS by the ROS agonist blocked the activation of PI3K. In conclusion, these findings suggested that Se and Tau combination was better than either substance alone in protecting LPS-induced mammary inflammatory lesions by upregulating the PI3K/Akt/mTOR signaling pathway.

Assessing and counteracting fibrosis is a cornerstone of the treatment of CKD secondary to systemic and renal limited autoimmune disorders

Chronic kidney disease (CKD) is an increasing cause of morbidity and mortality worldwide. Besides the higher prevalence of diabetes, hypertension and aging worldwide, immune mediated disorders remain an important cause of kidney disease and are especially prevalent in young adults. Regardless of the initial insult, final pathway to CKD and kidney failure is always the loss of normal tissue and fibrosis development, in which the dynamic equilibrium between extracellular matrix synthesis and degradation is disturbed, leading to excessive production and accumulation. During fibrosis, a multitude of cell types intervene at different levels, but myofibroblasts and inflammatory cells are considered critical in the process. They exert their effects through different molecular pathways, of which transforming growth factor β (TGF-β) has demonstrated to be of particular importance. Additionally, CKD itself promotes fibrosis due to the accumulation of toxins and hormonal changes, and proteinuria is simultaneously a manifestation of CKD and a specific driver of renal fibrosis. Pathways involved in renal fibrosis and CKD are closely interrelated, and although important advances have been made in our knowledge of them, it is still necessary to translate them into clinical practice. Given the complexity of this process, it is highly likely that its treatment will require a multi-target strategy to control the origin of the damage but also the mechanisms that perpetuate it. Fortunately, rapid technology development over the last years and new available drugs in the nephrologist's armamentarium give reasons for optimism that more personalized assistance for CKD and renal fibrosis will appear in the future.

Revisiting the Effects of Different Dietary Sources of Selenium on the Health and Performance of Dairy Animals: a Review

Selenium (Se) is one of the most important essential trace elements in livestock production. It is a structural component in at least 25 selenoproteins such as the iodothyronine deiodinases and thioredoxin reductases as selenocysteine at critical positions in the active sites of these enzymes. It is also involved in the synthesis of the thyroid hormone and influences overall body metabolism. Selenium being a component of the glutathione peroxidase enzyme also plays a key role in the antioxidant defense system of animals. Dietary requirements of Se in dairy animals depend on physiological status, endogenous Se content, Se source, and route of administration. Most of the dietary Se is absorbed through the duodenum in ruminants and also some portion through the rumen wall. Inorganic Se salts such as Na-selenate and Na-selenite have shown lower bioavailability than organic and nano-Se. Selenium deficiency has been associated with reproductive disorders such as retained placenta, abortion, early embryonic death, and infertility, together with muscular diseases (like white muscle disease and skeletal and cardiac muscle necrosis). The deficiency of Se can also affect the udder health particularly favoring clinical and subclinical mastitis, along with an increase of milk somatic cell counts in dairy animals. However, excessive Se supplementation (5 to 8 mg/kg DM) can lead to acute toxicity including chronic and acute selenosis. Se is the most vital trace element for the optimum performance of dairy animals. This review focuses to provide insights into the comparative efficacy of different forms of dietary Se (inorganic, organic, and nano-Se) on the health and production of dairy animals and milk Se content.

Selenomethionine activates selenoprotein S, suppresses Fas/FasL and the mitochondrial pathway, and reduces Escherichia coli-induced apoptosis of bovine mammary epithelial cells

Escherichia coli is a major environmental pathogen causing bovine mastitis, characterized by cell death and mammary tissue damage. Apoptosis, a form of cell death, has an important role in the pathogenesis of mastitis. Selenium, an essential trace element, protects against mastitis by acting through several biochemical pathways, potentially including prevention of apoptosis. Our objective was to investigate whether selenomethionine (SeMet) attenuated E. coli-induced apoptosis in bovine mammary epithelial cells (bMEC). These cells were cultured in vitro and treated with 0, 5, 10, 20, and 40 μM SeMet for 12 h, with or without E. coli (multiplicity of infection of 5) for 8 h. Treatment with SeMet/Z-IE(OMe)TD(OMe)-FMK (ZIK)/Z-LE(OMe)HD(OMe)-FMK (ZLK, specific inhibitors of caspase-8 and -9, respectively) significantly counteracted effects of E. coli on bMEC. Specifically, SeMet upregulated selenoprotein S (SeS) and increased mitochondrial membrane potential and the ratio of Bcl-2 and Bax. Furthermore, it decreased protein expressions of Fas, FasL, FADD, cleaved caspase-8, cytochrome c, cleaved caspase-9, and cleaved caspase-3, namely, decreasing protein expression of the Fas/FasL and mitochondrial pathways. Furthermore, it downregulated total apoptosis indexes in E. coli-infected bMEC. Although ZIK and ZLK (specific inhibitors of caspases 8 and 9, respectively) significantly inhibited Fas/FasL and the mitochondrial apoptotic pathway and apoptosis indexes, respectively, substantial apoptosis still occurred. In conclusion, SeMet attenuated E. coli-induced apoptosis in bMEC by activating SeS, associated with Fas/FasL and mitochondrial pathways.

TGF-β1 Signaling: Immune Dynamics of Chronic Kidney Diseases

Chronic kidney disease (CKD) is a major cause of morbidity and mortality worldwide, imposing a great burden on the healthcare system. Regrettably, effective CKD therapeutic strategies are yet available due to their elusive pathogenic mechanisms. CKD is featured by progressive inflammation and fibrosis associated with immune cell dysfunction, leading to the formation of an inflammatory microenvironment, which ultimately exacerbating renal fibrosis. Transforming growth factor β1 (TGF-β1) is an indispensable immunoregulator promoting CKD progression by controlling the activation, proliferation, and apoptosis of immunocytes via both canonical and non-canonical pathways. More importantly, recent studies have uncovered a new mechanism of TGF-β1 for de novo generation of myofibroblast via macrophage-myofibroblast transition (MMT). This review will update the versatile roles of TGF-β signaling in the dynamics of renal immunity, a better understanding may facilitate the discovery of novel therapeutic strategies against CKD.