The effect of selenium on the proliferation of bovine endometrial epithelial cells in a lipopolysaccharide-induced damage model.

BACKGROUND: Endometritis is a common bovine postpartum disease. Rapid endometrial repair is beneficial for forming natural defense barriers and lets cows enter the next breeding cycle as soon as possible. Selenium (Se) is an essential trace element closely related to growth and development in animals. This study aims to observe the effect of Se on the proliferation of bovine endometrial epithelial cells (BEECs) induced by lipopolysaccharide (LPS) and to elucidate the possible underlying mechanism. RESULTS: In this study, we developed a BEECs damage model using LPS. Flow cytometry, cell scratch test and EdU proliferation assay were used to evaluate the cell cycle, migration and proliferation. The mRNA transcriptions of growth factors were detected by quantitative reverse transcription-polymerase chain reaction. The activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and Wnt/ß-catenin pathways were detected by Western blotting and immunofluorescence. The results showed that the cell viability and BCL-2/BAX protein ratio were significantly decreased, and the cell apoptosis rate was significantly increased in the LPS group. Compared with the LPS group, Se promoted cell cycle progression, increased cell migration and proliferation, and significantly increased the gene expressions of TGFB1, TGFB3 and VEGFA. Se decreased the BCL-2/BAX protein ratio, promoted ß-catenin translocation from the cytoplasm to the nucleus and activated the Wnt/ß-catenin and PI3K/AKT signaling pathways inhibited by LPS. CONCLUSIONS: In conclusion, Se can attenuate LPS-induced damage to BEECs and promote cell proliferation and migration in vitro by enhancing growth factors gene expression and activating the PI3K/AKT and Wnt/ß-catenin signaling pathways.

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.

PINK1/Parkin-mediated mitophagy enhances the survival of Staphylococcus aureus in bovine macrophages.

Mitochondria are cellular organelles that are involved in various metabolic processes, and damage to mitochondria can affect cell health and even lead to disease. Mitophagy is a mechanism by which cells selectively wrap and degrade damaged mitochondria to maintain cell homeostasis. However, studies have not focused on whether mitophagy is involved in the occurrence of Staphylococcus aureus (S. aureus)-induced mastitis in dairy cows. Here, we found that S. aureus infection of bovine macrophages leads to oxidative damage and mitochondria damage. The expression of LC3, PINK1 and Parkin was significantly increased after intracellular infection. We observed changes in the morphology of mitochondria and the emergence of mitochondrial autolysosomes in bovine macrophages by transmission electron microscopy and found that enhanced mitophagy promoted bacterial proliferation in the cell. In conclusion, this study demonstrates that S. aureus infection of bovine macrophages induces mitophagy through the PINK1/Parkin pathway, and this mechanism is used by the bacteria to avoid macrophage-induced death. These findings provide new ideas and references for the prevention and treatment of S. aureus infection.

Selenium suppressed the LPS-induced inflammation of bovine endometrial epithelial cells through NF-κB and MAPK pathways under high cortisol background.

The bovine uterus is susceptible to infection, and the elevated cortisol level due to stress are common in cows after delivery. The essential trace element selenium plays a pivotal role in the antioxidant and anti-inflammatory defence system of body. This study investigated whether selenium supplementation protected endometrial cells from inflammation in the presence of high-level cortisol. The primary bovine endometrial epithelial cells were subjected to Escherichia coli lipopolysaccharide to establish cellular inflammation model. The gene expression of inflammatory mediators and proinflammatory cytokines was measured by quantitative PCR. The key proteins of NF-κB and MAPK signalling pathways were detected by Western blot and immunofluorescence. The result showed that pre-treatment of Na2 SeO3 (1, 2 and 4 µΜ) decreased the mRNA expression of proinflammatory genes, inhibited the activation of NF-κB and suppressed the phosphorylation of extracellular signal-regulated kinase, P38MAPK and c-Jun N-terminal kinase. This inhibition of inflammation was more apparent in the presence of high-level cortisol (30 ng/mL). These results indicated that selenium has an anti-inflammatory effect, which is mediated via NF-κB and MAPK signalling pathways and is augmented by cortisol in bovine endometrial epithelial cells.

VAMP726 and VAMP725 regulate vesicle secretion and pollen tube growth in Arabidopsis.

KEY MESSAGE: VAMP726/VAMP725 and SYP131 can form a part of a SNARE complex to mediate vesicle secretion at the pollen tube apex. Secretory vesicle fusion with the plasma membrane of the pollen tube tip is a key step in pollen tube growth. Membrane fusion was mediated by SNAREs. However, little is known about the composition and function of the SNARE complex during pollen tube tip growth. In this study, we constructed a double mutant vamp725 vamp726 via CRISPR‒Cas9. Fluorescence labeling combined with microscopic observation, luciferase complementation imaging, co-immunoprecipitation and GST pull-down were applied in the study. We show that double mutation of the R-SNAREs VAMP726 and VAMP725 significantly inhibits pollen tube growth in Arabidopsis and slows vesicle exocytosis at the apex of the pollen tube. GFP-VAMP726 and VAMP725-GFP localize mainly to secretory vesicles and the plasma membrane at the apex of the pollen tube. In addition, fluorescence recovery after photobleaching (FRAP) experiments showed that mCherry-VAMP726 colocalizes with Qa-SNARE SYP131 in the central region of the pollen tube apical plasma membrane. Furthermore, we found that VAMP726 and VAMP725 can interact with the SYP131. Based on these results, we suggest that VAMP726/VAMP725 and SYP131 can form a part of a SNARE complex to mediate vesicle secretion at the pollen tube apex, and vesicle secretion may mainly occur at the central region of the pollen tube apical plasma membrane.

A unified DNA- and RNA-based NGS strategy for the analysis of multiple types of variants at the dual nucleic acid level in solid tumors.

BACKGROUND: Targeted next-generation sequencing (NGS) is a powerful and suitable approach to comprehensively identify multiple types of variants in tumors. RNA-based NGS is increasingly playing an important role in precision oncology. Both parallel and sequential DNA- and RNA-based approaches are expensive, burdensome, and have long turnaround times, which can be impractical in clinical practice. A streamlined, unified DNA- and RNA-based NGS approach is urgently needed in clinical practice. METHODS: A DNA/RNA co-hybrid capture sequencing (DRCC-Seq) approach was designed to capture pre-capture DNA and RNA libraries in a single tube and convert them into one NGS library. The performance of the DRCC-Seq approach was evaluated by a panel of reference standards and clinical samples. RESULTS: The average depth, DNA data ratio, capture ratio, and target coverage 250 (×) of the DNA panel data had a negative correlation with an increase in the proportion of RNA probes. The SNVs, indels, fusions, and MSI status were not affected by the proportion of RNA probes, but the copy numbers of the target genes were higher than expected in the standard materials, and many unexpected gene amplifications were found using D:R (1:2) and D:R (1:4) probe panels. The optimal ratio of DNA and RNA probes in the combined probe panel was 1:1 using the DRCC-Seq approach. The DRCC-Seq approach was feasible and reliable for detecting multiple types of variants in reference standards and real-world clinical samples. CONCLUSIONS: The DRCC-Seq approach is more cost-effective, with a shorter turnaround time and lower labor requirements than either parallel or sequential targeted DNA NGS and RNA NGS. It is feasible to identify multiple genetic variations at the DNA and RNA levels simultaneously in clinical practice.

Visible-Light-Induced α-C(sp3)-H Phosphinylation of Unactivated Ethers under Photocatalyst- and Additive-Free Conditions.

A photocatalyst- and additive-free visible-light-induced α-C(sp3)-H phosphinylation of unactivated ethers involving a C-O bond cleavage with molecular oxygen as the sole oxidant at room temperature has been achieved. This method provides a sustainable access to α-hydroxyphosphine oxides in up to 88% yield with good functional group compatibility under mild and neutral conditions (34 examples). Moreover, the subsequent two-step conversion of the resulting dihydroxy diarylphosphine oxides afforded α-phosphinylated cyclic ethers in good overall yields (10 examples).

Immortalization effect of SV40T lentiviral vectors on canine corneal epithelial cells.

BACKGROUND: Primary canine corneal epithelial cells (CCECs) easily become senescent, and cell proliferation is limited. Therefore, sampling for experimentation requires a large number of animals, which is problematic in terms of animal welfare and fails to maintain the stability of the cells for in vitro analyses. RESULTS: In this study, CCECs were separated and purified by trypsin and dispase II enzymatic analysis. Next, the cells were immortalized by transfection with a lentiviral vector expressing Simian vacuolating virus 40 large T (SV40T). The immortalized canine corneal epithelial cell line (CCEC-SV40T) was established by serial passages and monoclonal selection. The biological characteristics of CCEC-SV40T cells were evaluated based on the cell proliferation rate, cell cycle pattern, serum dependence, karyotype, and cytokeratin 12 immunofluorescence detection. In addition, we infected CCEC-SV40T cells with Staphylococcus pseudintermedius (S. pseudintermedius) and detected the inflammatory response of the cells. After the CCEC-SV40T cells were passaged continuously for 40 generations, the cells grew in a cobblestone pattern, which was similar to CCECs. The SV40T gene and cytokeratin 12 can be detected in each generation. CCEC-SV40T cells were observed to have a stronger proliferation capacity than CCECs. CCEC-SV40T cells maintained the same diploid karyotype and serum-dependent ability as CCECs. After CCEC-SV40T cells were infected with S. pseudintermedius, the mRNA expression levels of NLRP3, Caspase-1 and proinflammatory cytokines, including IL-1ß, IL-6, IL-8 and TNF-α, were upregulated, and the protein levels of MyD88, NLRP3 and the phosphorylation of Iκbα and p65 were upregulated. CONCLUSIONS: In conclusion, the CCEC-SV40T line was successfully established and can be used for in vitro studies, such as research on corneal diseases or drug screening.

Staphylococcus aureus facilitates its survival in bovine macrophages by blocking autophagic flux.

Staphylococcus aureus is a pathogen that is the causative agent of several human and veterinary infections and plays a critical role in the clinical and subclinical mastitis of cattle. Autophagy is a conserved pathogen defence mechanism in eukaryotes. Studies have reported that S aureus can subvert autophagy and survive in cells. Staphylococcus aureus survival in cells is an important cause of chronic persistent mastitis infection. However, it is unclear whether S aureus can escape autophagy in innate immune cells. In this study, initiation of autophagy due to the presence of S aureus was detected in bovine macrophages. We observed autophagic vacuoles increased after S aureus infection of bovine macrophages by transmission electron microscopy (TEM). It was also found that S aureus-infected bovine macrophages increased the expression of LC3 at different times(0, 0.5, 1, 1.5, 2, 2.5, 3 and 4 hours). Data also showed the accumulation of p62 induced by S aureus infection. Application of autophagy regulatory agents showed that the degradation of p62 was blocked in S aureus induced bovine macrophages. In addition, we also found that the accumulation of autophagosomes promotes S aureus to survive in macrophage cells. In conclusion, this study indicates that autophagy occurs in S aureus-infected bovine macrophages but is blocked at a later stage of autophagy. The accumulation of autophagosomes facilitates the survival of S aureus in bovine macrophages. These findings provide new insights into the interaction of S aureus with autophagy in bovine macrophages.

Different effects of cortisol on pro-inflammatory gene expressions in LPS-, heat-killed E.coli-, or live E.coli-stimulated bovine endometrial epithelial cells.

BACKGROUND: Bacterial infections are common in postpartum dairy cows. Cortisol level has been observed to increase in dairy cows during peripartum period, and is associated with the endometrial innate immunity against pathogens like E.coli. However, the mechanism underlying how cortisol regulates E.coli-induced inflammatory response in bovine endometrial epithelial cells (BEEC) remains elusive. RESULTS: Cortisol decreased the expressions of IL1ß, IL6, TNF-α, IL8, and TLR4 mRNA in BEEC treated with LPS or heat-killed E.coli, but up-regulated these gene expressions in BEEC stimulated by live E.coli. CONCLUSION: Cortisol exerted the anti-inflammatory action on LPS- or heat-killed E.coli-stimulated BEEC, but the pro-inflammatory action on live E.coli-induced BEEC.

Effects of long-distance transportation on blood constituents and composition of the nasal microbiota in healthy donkeys.

BACKGROUND: This study aims to determine the effects of transportation on the nasal microbiota of healthy donkeys using 16S rRNA sequencing. RESULTS: Deep nasal swabs and blood were sampled from 14 donkeys before and after 21 hours' long-distance transportation. The values of the plasma hormone (cortisol (Cor), adrenocorticotrophic hormone (ACTH)), biochemical indicators (total protein (TP), albumin (ALB), creatinine (CREA), lactic dehydrogenase (LDH), aspartate transaminase (AST), creatine kinase (CK), blood urea (UREA), plasma glucose (GLU)) and blood routine indices (white blood cell (WBC), lymphocyte (LYM), neutrophil (NEU), red blood cell (RBC), hemoglobin (HGB)) were measured. 16S rRNA sequencing was used to assess the nasal microbiota, including alpha diversity, beta diversity, and phylogenetic structures. Results showed that levels of Cor, ACTH, and heat-shock protein 90 (HSP90) were significantly increased (p < 0.05) after long-distance transportation. Several biochemical indicators (AST, CK) and blood routine indices (Neu, RBC, and HGB) increased markedly (p < 0.05), but the LYM decreased significantly (p < 0.05). Nine families and eight genera had a mean relative abundance over 1%. The predominant phyla in nasal microbiota after and before transportation were Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Transportation stress induced significant changes in terms of nasal microbiota structure compared with those before transportation based on principal coordinate analysis (PCoA) coupled with analysis of similarities (ANOSIM) (p < 0.05). Among these changes, a notably gain in Proteobacteria and loss in Firmicutes at the phylum level was observed. CONCLUSIONS: These results suggest transportation can cause stress to donkeys and change the richness and diversity of nasal microbiota. Further studies are required to understand the potential effect of these microbiota changes on the development of donkey respiratory diseases.

The proliferative effect of cortisol on bovine endometrial epithelial cells.

BACKGROUND: Bovine endometrial epithelial cells (BEECs) undergo regular regeneration after calving. Elevated cortisol concentrations have been reported in postpartum cattle due to various stresses. However, the effects of the physiological level of cortisol on proliferation in BEECs have not been reported. The aim of this study was to investigate whether cortisol can influence the proliferation properties of BEECs and to clarify the possible underlying mechanism. METHODS: BEECs were treated with different concentrations of cortisol (5, 15 and 30 ng/mL). The mRNA expression of various growth factors was detected by quantitative reverse transcription-polymerase chain reaction (qPCR), progression of the cell cycle in BEECs was measured using flow cytometric analysis, and the activation of the Wnt/ß-catenin and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways was detected with Western blot and immunofluorescence. RESULTS: Cortisol treatment resulted in upregulated mRNA levels of vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF); however, it had no influence on transforming growth factor-beta1 (TGF-ß1). Cortisol (15 ng/mL) accelerated the cell cycle transition from the G0/G1 to the S phase. Cortisol upregulated the expression of ß-catenin, c-Myc, and cyclinD1 and promoted the phosphorylation of PI3K and AKT. CONCLUSIONS: These results demonstrated that cortisol may promote proliferation in BEECs by increasing the expression of some growth factors and activating the Wnt/ß-catenin and PI3K/AKT signaling pathways.

Changes in the blood routine, biochemical indexes and the pro-inflammatory cytokine expressions of peripheral leukocytes in postpartum dairy cows with metritis.

BACKGROUND: The aim of the present study was to clarify the changes in complete blood count, blood biochemistry, and the gene expressions of pro-inflammatory cytokines of peripheral white blood cells in postpartum dairy cows with metritis. RESULTS: The cows were assigned to the control group (n = 28) or the metritis group (n = 28), retrospectively. Blood samples were taken 7 days before the estimated parturition (- 7 d), on the day of parturition (0 d), and 7 and 30 d after parturition. There was no difference in blood indexes between the control group and the metritis group at - 7 d. The WBC, granulocytes and monocytes were generally higher at 7 and 30 d in the metritis group than the control. In comparison with the controls, all liver function parameters and triglyceride levels at 0, 7 and 30 d, and the creatinine level at 7 and 30 d were higher in cows with metritis. The concentrations of Ca and P at 0, 7 and 30 d, and of glucose at 0 d were lower for cows in the metritis group compared with cows in the control group. Among these parameters, the WBC at 30 d, the aspartate aminotransferase activity (AST) at 7 d exceeded normal ranges (WBC: 5.0 ~ 16.0 × 109/L; AST: 42.5 ~ 98 U/L), whereas the concentrations of glucose and Ca from 0 to 30 d were below normal ranges (glucose: 2.5 ~ 4.5 mmol/L; Ca: 2.2 ~ 2.5 mmol/L) in the metritis group. The gene expressions of pro-inflammatory cytokines in the metritis group were higher than those in the control group, including the IL-1α at 7d, the IL-1ß at - 7, 0 and 7 d, the IL-6 at - 7, 0, 7 and 30 d, the IL-8 at 0, 7 and 30 d, and the TNF-α at 7 and 30 d. CONCLUSION: The cows with metritis experienced systemic inflammation for 4 weeks after calving, the impaired hepatic function, and the altered metabolic status with increased triglyceride level and decreased concentrations of glucose, Ca and P.

Staphylococcus aureus induces autophagy in bovine mammary epithelial cells and the formation of autophagosomes facilitates intracellular replication of Staph. aureus.

Staphylococcus aureus is an important pathogen causing chronic and subclinical mastitis of cows. Autophagy is an important regulatory mechanism that participates in the elimination of invading pathogenic organisms. Here, we hypothesize that autophagy is involved in the process of Staph. aureus survival in bovine mammary epithelial cells (BMEC). In this study, we detected the expression of autophagy-related proteins during infection and assessed the effect of autophagosome formation and degradation on the proliferation of intracellular Staph. aureus. Infection with Staph. aureus increased the protein expression of microtubule-associated protein 1 light chain 3-II (MAP1LC3, also called LC3-II) and sequestosome-1 (SQSTM1, also called p62) in BMEC. After infection, the formation of the autophagosomes increased but the autophagosomes and lysosomes could not fuse normally to form autolysosomes. When the formation of the autophagosomes was enhanced or the degradation of the autolysosomes was inhibited, the number of Staph. aureus in the BMEC increased. However, the intracellular proliferation of Staph. aureus was slowed when formation of autophagosomes was inhibited. Therefore, autophagy was induced in BMEC challenged by Staph. aureus but the autophagic flux was obstructed. Inhibiting the formation of autophagosomes in BMEC facilitated the clearance of intracellular Staph. aureus, which may offer a new strategy for the treatment of mastitis in cows.

Selenium ameliorates Staphylococcus aureus-induced inflammation in bovine mammary epithelial cells by inhibiting activation of TLR2, NF-κB and MAPK signaling pathways.

BACKGROUND: Staphylococcus aureus (S. aureus) internalization into bovine mammary epithelial cells (bMECs) is considered an important pathogenic mechanism for the establishment of mastitis. Given the interesting link between selenium (Se) status and mastitis, our objective was to prove that Se was essential to suppress pro-inflammatory mediators, in part, by modulation of Toll-like receptor2 (TLR2), nuclear factor kappaB (NF-κB) and mitogen activated protein kinase (MAPK) signal transduction pathway in bMECs. RESULTS: Results showed that Se (0~ 16 µM) did not affect the growth of bMECs. The mRNA expression of TLR2, Myeloid differentiation factor 88 (Myd88), Interleukin-1 receptor-associated kinase4 (Irak4), Interleukin-1 receptor-associated kinase1 (Irak1) and TNF receptor-associated factor6 (Traf6) in TLR2 signal pathway were increased or significantly increased by S. aureus. Se played an important role in regulating the genes expression of TLR2, Myd88, Traf6 but not in controlling the expression of Irak4 and Irak1. In addition, Se exerted strong inhibitory effects on the genes expression of tumor necrosis factor-alpha (TNF-α), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) induced by S. aureus. To further investigate the possible signaling mechanisms involved in the processes, we analyzed the role of MAPK and NF-κB signaling pathway in inflammation response in S. aureus-stimulated bMECs in vitro. Results showed that the phosphorylation of inhibitory kappaB alpha (IκBα), p65, p38 and extracellular regulated protein kinase (Erk) were significantly increased in S. aureus-stimulated bMECs. It indicated that S. aureus activated NF-κB and MAPK signaling pathway. We also examined the effects of Se on the phosphorylation of IκBα, p65, p38 and Erk in NF-κB and MAPK signaling pathway, which have well been proved to control the synthesis and release of pro-inflammatory mediators during inflammation. The findings are exciting, that pretreatment with Se (4, 8 µM) significantly suppressed the phosphorylation of IκBα, p65, p38 and Erk. CONCLUSIONS: These results suggest that Se down-regulates inflammatory mediators TNF-α, IL-1ß and IL-6 gene expressions via TLR2, NF-κB and MAPK signaling pathway in S. aureus-stimulated bMECs, which may be responsible for the anti-inflammatory effect of Se.

Cortisol modulates inflammatory responses in LPS-stimulated RAW264.7 cells via the NF-κB and MAPK pathways.

BACKGROUND: The uteruses of most dairy cattle are easily infected by bacteria, especially gram-negative bacteria, following parturition. Macrophages are important cells of the immune system and play a critical role in the inflammatory response. In addition, cortisol levels become significantly increased due to the stress of parturition in dairy cattle, and cortisol is among the most widely used and effective therapies for many inflammatory diseases. In this study, we assessed the anti-inflammatory effects and potential molecular mechanisms of cortisol using a Lipopolysaccharide (LPS)-induced RAW264.7 macrophage cell line. RESULTS: Cortisol significantly suppressed the production of prostaglandin E2 (PGE2) and decreased the gene and protein expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose-dependent manner. Moreover, cortisol inhibited the mRNA expression of pro-inflammatory cytokines including tumor necrosis factor alpha (TNFα), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6) and decreased IL-1ß secretion in an LPS-treated RAW264.7 macrophage cell line. Moreover, we found that cortisol suppressed nuclear factor-kappa B (NF-κB) signaling in RAW264.7 macrophages stimulated with LPS. This suppression was mediated by the inhibition of IκBα degradation and NF-κB p65 phosphorylation. In addition, cortisol also suppressed the phosphorylation of mitogen-activated protein kinases (MAPK) such as extracellular signal-regulated kinase (ERK1/2), p38 MAPK, and c-Jun N-terminal kinase/stress-activated protein kinase (JNK). CONCLUSIONS: These results suggest that high cortisol levels can attenuate LPS-induced inflammatory responses in the RAW264.7 macrophage cell line by regulating the NF-κB and MAPK signaling pathways.

Immunohistochemical localization and mRNA quantification of osteopontin and Tamm-Horsfall protein in canine renal tissue after potassium oxalate injection.

BACKGROUND: Urinary macromolecules contribute to promoting or inhibiting crystal retention in renal tissue and stone formation. Osteopontin (OPN) and Tamm-Horsfall protein (THP) are the most important proteins involved in this process. Although these two proteins were discovered a long time ago, their role in setting kidney stone formation has not yet been fully investigated. We conducted a study to explore the role of OPN and THP in canine renal oxalosis. Ten dogs were carefully examined prior to the study. Six dogs were assigned to the treatment group and were injected intravenously with 0.5 M potassium oxalate (KOx). The other four dogs were assigned to a control group and were injected intravenously with 0.9% NaCl three times a day (tid) for 7 consecutive days. Then kidneys were harvested for pathological, immunohistochemical examination and OPN and THP mRNA expression levels were quantified by quantitative real-time PCR. RESULTS: Calcium oxalate crystals deposition was observed in both renal cortex and medulla. Immunohistochemistry examination revealed increased tissue expression of OPN in the renal tissue while THP was significantly decreased. OPN mRNA expression level significantly increased in treated dogs compared to that in the controls, while THP mRNA level significantly decreased. CONCLUSION: Together, these results suggest that THP and OPN are both involved in the pathogenesis and response to oxalate exposure.

The effect and mechanism of selenium supplementation on the proliferation capacity of bovine endometrial epithelial cells exposed to lipopolysaccharide in vitro under high cortisol background.

Bovine endometritis severely inhibits uterine repair and causes considerable economic loss. Besides, parturition-induced high cortisol levels inhibit immune function, reduce cell proliferation, and further inhibit tissue repair. Selenium (Se) is an essential trace element for animals to maintain normal physiological function and has powerful antioxidant functions. This study investigated whether Se supplementation reduces endometrial damage and promotes tissue repair in cows with endometritis under stress and explored the underlying mechanism. Primary bovine endometrial epithelial cells were isolated and purified from healthy cows. The cells were treated with different combinations of lipopolysaccharide (LPS), cortisol, and various concentrations of Se. Data showed that LPS stimulation inhibited cell proliferation and increased cell apoptosis. High levels of cortisol further exacerbated these effects. Flow cytometry, scratch wound healing tests, and 5-ethynyl-2'-deoxyuridine (EdU) proliferation assays showed that Se supplementation promoted cell cycle progression, cell migration, and cell proliferation in the presence of LPS and cortisol. The quantitative PCR results showed that the expression of related growth factors was increased after Se supplementation. After administering various inhibitors, we further demonstrated that Se supplementation decreased the activity of glycogen synthetase kinase 3ß (GSK-3ß) through the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway to reduce the degradation of ß-catenin except the Wnt signal to promote cell proliferation. In conclusion, Se supplementation attenuated the cell damage induced by LPS at high cortisol levels and increased cell proliferation to promote uterine repair by elevating the mRNA expression of TGFB3 and VEGFA and activating the PI3K/AKT/GSK-3ß/ß-catenin signaling pathway.

After parturition, endometritis is a common bovine disease, which hinders endometrial repair and reduces bovine economic value. Besides, parturition-induced high cortisol levels cause immunosuppression, aggravate infection, and further inhibit cell proliferation and tissue repair. As an essential trace element, adding selenium to feed helps to maintain the normal physiological function of animals. This study developed a cellular model using lipopolysaccharide (LPS) and cortisol to simulate cows with endometritis in stress conditions. The results showed that Se supplementation attenuated bovine endometrial epithelial cell damage and promoted their proliferation in the presence of LPS and high cortisol levels, which are positively correlated with the concentration of Se. Besides, this study proved another molecular mechanism for Se to regulate ß-catenin except for the Wnt signal by affecting the ß-catenin degradation pathway.

Selenomethionine Inhibits NF-κB-mediated Inflammatory Responses of Bovine Mammary Epithelial Cells Caused by Klebsiella pneumoniae by Increasing Autophagic Flux.

Klebsiella pneumoniae (K. pneumoniae) is one of the major pathogens causing bovine clinical mastitis. Autophagy maintains cellular homeostasis and resists excessive inflammation in eukaryotic organisms. Selenomethionine (Se-Met) is commonly used as a source of selenium supplementation for dairy cows. This study aimed to investigate the effects of Se-Met on inflammatory responses mediated by nuclear factor-kappa B (NF-κB) through autophagy. We infected bovine mammary epithelial cell line (MAC-T) with K. pneumoniae and examined the expression of autophagy-related proteins and changes in autophagic vesicles, LC3 puncta, and autophagic flux at various intervals. The results showed that K. pneumoniae activated the early-stage autophagy of MAC-T cells. The levels of LC3-II, Beclin1, and ATG5, as well as the number of LC3 puncta and autophagic vesicles, increased after 2 h post-treatment. However, the late-stage autophagic flux was blocked. Furthermore, the effect of autophagy on NF-κB-mediated inflammation was investigated with different autophagy levels. The findings showed that enhanced autophagy inhibited the K. pneumoniae-induced inflammatory responses of MAC-T cells. The opposite results were found with the inhibition of autophagy. Finally, we examined the effect of Se-Met on NF-κB-mediated inflammation based on autophagy. The results indicated that Se-Met alleviated K. pneumoniae-induced autophagic flux blockage, inhibited NF-κB-mediated inflammation, and decreased the adhesion of K. pneumoniae to MAC-T cells. The inhibitory effect of Se-Met on NF-κB-mediated inflammation could be partially blocked by the autophagy inhibitor chloroquine (CQ). Overall, Se-Met attenuated K. pneumoniae-induced NF-κB-mediated inflammatory responses by enhancing autophagic flux.

Autophagy activation alleviates the LPS-induced inflammatory response in endometrial epithelial cells in dairy cows.

PROBLEM: Endometritis is a common disease that affects dairy cow reproduction. Autophagy plays a vital role in cellular homeostasis and modulates inflammation by regulating interactions with innate immune signaling pathways. However, little is known about the regulatory relationship between autophagy and inflammation in bovine endometrial epithelial cells (BEECs). Thus, we aimed to determine the role of autophagy in the inflammatory response in BEECs. METHODS OF STUDY: In the present study, the expression levels of proinflammatory cytokines were measured by quantitative real-time polymerase chain reaction. Changes in the nuclear factor-κB (NF-κB) pathway and autophagy were determined using immunoblotting and immunocytochemistry. The induction of autophagosome formation was visualized by transmission electron microscopy. RESULTS: Our results demonstrated that autophagy activation was inhibited in LPS-treated BEECs, while activation of the NF-κB pathway and the mRNA expression of IL-6, IL-8, and TNF-α were increased. Furthermore, blocking autophagy with the inhibitor chloroquine increased NF-κB signaling pathway activation and proinflammatory factor expression in LPS-treated BEECs. Conversely, activation of autophagy with the agonist rapamycin inhibited the NF-κB signaling pathway and downregulated proinflammatory factors. CONCLUSIONS: These data indicated that LPS-induced inflammation was related to the inhibition of autophagy in BEECs. Thus, the activation of autophagy may represent a novel therapeutic strategy for eliminating inflammation in BEECs.