scholarly journals Establishment of inflammatory model of bovine mammary epithelial cells induced by lipoteichoic acid

Author(s):  
Xu Ping ◽  
Tetiana Fotina ◽  
Hanna Fotina ◽  
Sanhu Wang

The mammary gland of the cow is particularly susceptible to infections of a wide range of pathogenic bacteria, including both Gram-positive and Gram-negative bacteria. The endotoxins of these pathogenic bacteria include peptidoglycan (PGN), lipoteichoic acid (LTA) and lipopolysaccharide (LPS), and they are the pathogen-associated molecular patterns (PAMPs) to induce mastitis. Cow mastitis is a detrimental factor in dairy farming industry. Lipoteichoic acid (LTA) is the main component of Staphylococcus aureus cell wall and the key cytotoxic factor causing inflammation. The aims of our work was to establish inflammatory model of study procedures were approved by the Animal Care and Use Committee of the Sumy National Agricultural University, Sumy, Ukraine, and the Henan Institute of Science and Technology, Xinxiang, China, and performed in accordance with the animal welfare and ethics guidelines. The BMECs harvested from mid-lactation dairy cow milk were isolated by our laboratory. Briefly, the base medium for this cell is DMEM/F-12 (Gibco, USA, cat.12400-024). The complete growth medium included 10% fetal bovine serum (Biological Industries, Israel, cat.04-011-1A/B), DMEM/F-12, and 10 ng/mL epidermal growth factor (Sigma, USA, cat. E4127). Cells were maintained at 37℃in an incubator containing 5% CO2. When cells grew to 80% confluency, the cells were rinsed twice with PBS, and then the primary mammary epithelial cells were trypsinized with 0.25% trypsin plus 0.02% EDTA and passaged. In this study, one inflammatory bovine mammary epithelial cell (BMEC) model was established by infecting the cells with LTA. The BMEC viability induced by LTA were evaluated. The expressions of pro-inflammatory cytokines (TNF-α and IL-6) were measured by ELISA and RT- qPCR. The results showed that the treatment of BMECs with LTA at 20 ng/μL for 24 h obviously improved TNF-α and IL-6 protein and gene expression levels. The establishment of the model will play an important role in the screening of anti-inflammatory drugs and the study of the mechanism of action in the future.

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Zhuo-Ma Luoreng ◽  
Da-Wei Wei ◽  
Xing-Ping Wang

AbstractMastitis is a complex inflammatory disease caused by pathogenic infection of mammary tissue in dairy cows. The molecular mechanism behind its occurrence, development, and regulation consists of a multi-gene network including microRNA (miRNA). Until now, there is no report on the role of miR-125b in regulating mastitis in dairy cows. This study found that miR-125b expression is significantly decreased in lipopolysaccharide (LPS)-induced MAC-T bovine mammary epithelial cells. Also, its expression is negatively correlated with the expression of NF-κB inhibitor interacting Ras-like 2 (NKIRAS2) gene. MiR-125b target genes were identified using a double luciferase reporter gene assay, which showed that miR-125b can bind to the 3′ untranslated region (3′ UTR) of the NKIRAS2, but not the 3′UTR of the TNF-α induced protein 3 (TNFAIP3). In addition, miR-125b overexpression and silencing were used to investigate the role of miR-125b on inflammation in LPS-induced MAC-T. The results demonstrate that a reduction in miR-125b expression in LPS-induced MAC-T cells increases NKIRAS2 expression, which then reduces NF-κB activity, leading to low expression of the inflammatory factors IL-6 and TNF-α. Ultimately, this reduces the inflammatory response in MAC-T cells. These results indicate that miR-125b is a pro-inflammatory regulator and that its silencing can alleviate bovine mastitis. These findings lay a foundation for elucidating the molecular regulation mechanism of cow mastitis.


Author(s):  
Zhi Chen ◽  
Yi Zhang ◽  
Jingpeng Zhou ◽  
Yu Tian ◽  
Qiaoni Zhou ◽  
...  

Abstract Background Effective prevention and treatment of cow mastitis can provide a good guarantee for the healthy growth of cows and the qualified production of dairy products. The main purpose of this study was to explore the effect of tea tree oil on lipopolysaccharide (LPS) -induced mastitis in dairy cows, and the key gene in LPS -stimulated bovine mammary epithelial cells (BMECs) was identified. Results In this study, a model of mastitis induced by LPS was constructed, to which tea tree oil and LPS were added. The protective effects of tea tree oil on LPS-induced mastitis in BMECs were verified by the CCK-8 method, flow cytometry, real-time fluorescence quantitative detection, ELISA and other methods. The results showed that LPS at a concentration of 200 μg/ml could reduce the proliferative activity of the cells, induce a high proportion of apoptosis, and promote the expression of TNF-α, IL-6 and STAT1. Upon addition of tea tree oil, the proportion of apoptosis was reduced, and the expression of NF-κB, MAPK and caspase-3 was inhibited. Mammary epithelial cells were compared under control and LPS-treatment conditions and analyzed by second-generation sequencing. A total of 1270 mRNAs were identified as differentially expressed, of which 787 genes were upregulated and 483 were downregulated. These differentially expressed genes include TNF - α, IL6, STAT1, mapk4, etc. H&E staining and immunohistochemistry were used to verify the function of candidate genes. TNF-α and IL6 were observed to play important roles in mediating the preventive effect of tea tree oil on mastitis in LPS-stimulated bovine mammary epithelial cells. Conclusions The results showed that tea tree oil had a protective effect against LPS-induced mastitis. TNF - α and IL6 may be the marker genes of LPS-induced mastitis which provided a theoretical basis and experimental support for further research to determine new strategies for the prevention and treatment of mastitis and improvement of milk quality.


Microbiology ◽  
2009 ◽  
Vol 155 (5) ◽  
pp. 1505-1515 ◽  
Author(s):  
Susana Martínez-Pulgarín ◽  
Gustavo Domínguez-Bernal ◽  
José A. Orden ◽  
Ricardo de la Fuente

Staphylococcus aureus produces a variety of virulence factors that allow it to cause a wide range of infections in humans and animals. In the latter, S. aureus is a leading cause of intramammary infections. The contribution of catalase (KatA), an enzyme implicated in oxidative stress resistance, and beta-toxin (Hlb), a haemolysin, to the pathogenesis of S. aureus is poorly characterized. To investigate the role of these enzymes as potential virulence factors in S. aureus, we examined the intracellular survival of ΔkatA, Δhlb and ΔkatA Δhlb mutants in murine macrophages (J774A.1) and bovine mammary epithelial cells (MAC-T), and their virulence in different murine and ovine models. Catalase was not required for the survival of S. aureus within either J774A.1 or MAC-T cells. However, it was necessary for the intracellular proliferation of the bacterium after invasion of MAC-T cells. In addition, catalase was not needed for the full virulence of S. aureus in mice. Deletion of the hlb gene had no effect on the intracellular survival of S. aureus in J774A.1 cells but did cause a slight increase in survival in MAC-T cells. Furthermore, like catalase, beta-toxin was not required for complete virulence of S. aureus in murine models. Unexpectedly, the ΔkatA Δhlb mutant showed a notably increased persistence in both cell lines, and was significantly less virulent for mice than were the wild-type strain and single mutants. Most interestingly, it was also markedly attenuated in intramammary and subcutaneous infections in ewes and lambs.


2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Yuxiang Shi ◽  
Wenpeng Zhao ◽  
Gang Liu ◽  
Tariq Ali ◽  
Peng Chen ◽  
...  

Abstract Background Klebsiella pneumoniae, an environmental pathogen causing mastitis in dairy cattle, is often resistant to antibiotics. K. pneumoniae was used as the host bacteria to support bacteriophage replication; 2 bacteriophages, CM8-1 and SJT-2 were isolated and considered to have therapeutic potential. In the present study, we determined the ability of these 2 bacteriophages to mitigate cytotoxicity, pathomorphological changes, inflammatory responses and apoptosis induced by K. pneumoniae (bacteriophage to K. pneumoniae MOI 1:10) in bovine mammary epithelial cells (bMECs) cultured in vitro. Results Bacteriophages reduced bacterial adhesion and invasion and cytotoxicity (lactate dehydrogenase release). Morphological changes in bMECs, including swelling, shrinkage, necrosis and hematoxylin and eosin staining of cytoplasm, were apparent 4 to 8 h after infection with K. pneumoniae, but each bacteriophage significantly suppressed damage and decreased TNF-α and IL-1β concentrations. K. pneumoniae enhanced mRNA expression of TLR4, NF-κB, TNF-α, IL-1β, IL-6, IL-8, caspase-3, caspase-9 and cyt-c in bMECs and increased apoptosis of bMECs, although these effects were mitigated by treatment with either bacteriophage for 8 h. Conclusions Bacteriophages CM8-1 and SJT-2 mitigated K. pneumoniae-induced inflammation in bMECs cultured in vitro. Therefore, the potential of these bacteriophages for treating mastitis in cows should be determined in clinical trials.


Cytokine ◽  
2005 ◽  
Vol 31 (1) ◽  
pp. 72-86 ◽  
Author(s):  
Ylva Strandberg ◽  
Christian Gray ◽  
Tony Vuocolo ◽  
Laurelea Donaldson ◽  
Mary Broadway ◽  
...  

2021 ◽  
Vol 8 ◽  
Author(s):  
Abdelaziz Adam Idriss Arbab ◽  
Xubin Lu ◽  
Ismail Mohamed Abdalla ◽  
Amer Adam Idris ◽  
Zhi Chen ◽  
...  

The objective of this research was to explore the effect of metformin on the lipoteichoic acid (LTA)–induced mastitis model using isolated primary bovine mammary epithelial cells (PBMECs). The PBMECs were exposed to either 3 mM metformin for 12 h as a metformin group (MET) or 100 μg/mL LTA for 6 h as LTA group (LTA). Cells pretreated with 3 mM metformin for 12 h followed by washing and 100 μg/mL LTA exposure for 6 h served as the MET + LTA group. Phosphate-buffered saline was added to cells as the control group. PBMECs pretreated with different metformin doses were analyzed by a flow cytometry (annexin V–fluorescein isothiocyanate assay) to detect the cell apoptotic rate. We performed quantitative reverse transcriptase–polymerase chain reaction and Western blot analysis to evaluate the inflammatory and oxidative responses to metformin and LTA by measuring cellular cytotoxicity, mRNA expression, and protein expression. Immunofluorescence was used to evaluate nuclear localization. The results showed that the gene expression of COX2, IL-1β, and IL-6 significantly increased in the cells challenged with LTA doses compared to control cells. In inflammatory PBMECs, metformin attenuated LTA-induced expression of inflammatory genes nuclear factor κB (NF-κB) p65, tumor necrosis factor α, cyclooxygenase 2, and interleukin 1β, as well as the nuclear localization and phosphorylation of NF-κBp65 protein, but increased the transcription of nuclear factor erythroid 2–related factor 2 (Nrf2) and Nrf2-targeted antioxidative genes heme oxygenase-1 (HO-1) and Gpx1, as well as the nuclear localization of HO-1 protein. Importantly, metformin-induced activation of Nrf2 is AMP-activated protein kinase (AMPK)–dependent; as metformin-pretreated PBMECs activated AMPK signaling via the upregulation of phosphorylated AMPK levels, cell pretreatment with metformin also reversed the translocation of Nrf2 that was LTA inhibited. This convergence between AMPK and Nrf2 pathways is essential for the anti-inflammatory effect of metformin in LTA-stimulated PBMECs. Altogether, our results indicate that metformin exerts anti-inflammation and oxidative stress through regulation of AMPK/Nrf2/NF-κB signaling pathway, which highlights the role of AMPK as a potential therapeutic strategy for treatment of bovine mastitis.


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