scholarly journals Niacin Alleviates Dairy Cow Mastitis by Regulating the GPR109A/AMPK/NRF2 Signaling Pathway

2020 ◽  
Vol 21 (9) ◽  
pp. 3321 ◽  
Author(s):  
Wenjin Guo ◽  
Juxiong Liu ◽  
Wen Li ◽  
He Ma ◽  
Qian Gong ◽  
...  

Mastitis is one of three bovine diseases recognized as a cause of substantial economic losses every year throughout the world. Niacin is an important feed additive that is used extensively for dairy cow nutrition. However, the mechanism by which niacin acts on mastitis is not clear. The aim of this study is to investigate the mechanism of niacin in alleviating the inflammatory response of mammary epithelial cells and in anti-mastitis. Mammary glands, milk, and blood samples were collected from mastitis cows not treated with niacin (n = 3) and treated with niacin (30 g/d, n = 3) and healthy cows (n = 3). The expression of GPR109A, IL-6, IL-1β, and TNF-α in the mammary glands of the dairy cows with mastitis was significantly higher than it was in the glands of the healthy dairy cows. We also conducted animal experiments in vivo by feeding rumen-bypassed niacin. Compared with those in the untreated mastitis group, the somatic cell counts (SCCs) and the expression of IL-6, IL-1β, and TNF-α in the blood and milk were lower. In vitro, we isolated the primary bovine mammary epithelial cells (BMECs) from the mammary glands of the healthy cows. The mRNA levels of IL-6, IL-1β, TNF-α, and autophagy-related genes were detected after adding niacin, shRNA, compound C, trans retinoic acid, 3-methyladenine to BMECs. Then GPR109A, AMPK, NRF-2, and autophagy-related proteins were detected by Western blot. We found that niacin can activate GPR109A and phosphorylate AMPK, and promote NRF-2 nuclear import and autophagy to alleviate LPS-induced inflammatory response in BMECs. In summary, we found that niacin can reduce the inflammatory response of BMECs through GPR109A/AMPK/NRF-2/autophagy. We also preliminarily explored the alleviative effect of niacin on mastitis in dairy cows.

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.


1999 ◽  
Vol 161 (1) ◽  
pp. 77-87 ◽  
Author(s):  
YN Ilkbahar ◽  
G Thordarson ◽  
IG Camarillo ◽  
F Talamantes

Increasing evidence suggests that GH is important in normal mammary gland development. To investigate this further, we studied the distribution and levels of growth hormone receptor (GHR) and GH-binding protein (GHBP) in the mouse mammary gland. At three weeks of age, the epithelial component of the right fourth inguinal mammary gland of female mice was removed. These animals were then either maintained as virgins until they were killed or they were mated. One group of the mated mice was killed on day 18 of pregnancy and the remaining mated animals were allowed to carry their pups until term and were killed on day 6 of lactation. At the time of death, both the intact left and the de-epithelialized right mammary glands were collected from all three groups. Some of the intact glands served as a source of epithelial cells, free of stroma. The mRNA levels for GHR and GHBP were measured in intact glands, epithelia-cleared fat pads, and isolated mammary epithelial cells. GHR and GHBP mRNAs were expressed in both the mammary epithelium and stroma. However, the levels of both GHR and GHBP mRNAs were significantly higher in the stroma as compared with the epithelium component. This increase for both mRNAs was from 3- to 12-fold at each physiological state examined. In the intact gland, both GHR and GHBP transcripts were highest in virgins, declined during late pregnancy, and the lowest levels were found in the lactating gland. GHBP and GHR protein concentrations were also assessed in intact glands and epithelia-free fat pads. Similar to the mRNAs, GHR and GHBP protein levels (means+/-s.e.m.) in intact glands were highest in virgin mice (0.891+/-0.15 pmoles/mg protein and 0.136+/-0.26 pmoles/mg protein respectively), declined during late pregnancy (0. 354+/-0.111 pmoles/mg protein and 0.178+/-0.039 pmoles/mg protein respectively), and were lowest during lactation (0.096+0.037 pmoles/mg protein and 0.017+0.006 pmoles/mg protein respectively). Immunocytochemistry utilizing specific antisera against mouse (m) GHR and mGHBP revealed that the two proteins are localized to both the stroma and parenchyma of mouse mammary glands, with similar patterns of immunostaining throughout the different physiological stages analyzed. GHR immunolocalized to the plasma membrane and cytosol of mammary epithelial cells and adipocytes, whereas the GHBP immunostaining was nuclear and cytosolic. In conclusion, we report here that GHR and GHBP mRNAs and proteins are expressed in both the epithelium and the stroma of mammary glands of virgin, pregnant, and lactating mice. In intact glands, GHR and GHBP proteins, as well as their transcripts are higher in abundance in virgin relative to lactating mice. At all physiological stages, GHR and GHBP mRNA levels are higher in the stroma compared with the parenchyma. These findings indicate that the actions of GH in the mammary gland are both direct through its binding to the epithelia, and indirect by binding to the stroma and stimulation of IGF-I production which, in turn, affects mammary epithelial development.


2016 ◽  
Vol 60 (1) ◽  
pp. 71-80
Author(s):  
Qiong Yi ◽  
Xin Li ◽  
Yuan-Fang Li ◽  
Hang Yang ◽  
Xiao-Yi Zhang ◽  
...  

Abstract Introduction: The effects of Jin-Ying-Tang (JYT) on Toll-like Receptor 4 (TLR4) signalling transduction of lipopolysaccharide (LPS)-stimulated mouse mammary epithelial cells (MECs) in vitro were examined. Material and Methods: The cytotoxicity of JYT (0.06-62.50 mg/mL) on mouse MECs was determined by MTT assay. The MECs were co-cultured with LPS in the presence or absence of JYT (39.10 μg/mL, 391 μg/mL, 3910 μg/mL). The concentrations of interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) in the culture supernatants were detected by ELISA. The mRNA expression of TLR4 and downstream TLR4 signalling molecules such as myeloid differentiation factor 88 (MyD88), tumour necrosis factor receptor associated factor 6 (TRAF-6), inhibitor κB (IκB), and nuclear factor κB inducing kinase (NIK) were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Results: The results showed that the IC50 of JYT on MECs was 12.25 mg/mL and JYT could significantly decrease the concentrations of IL-6 and TNF-α in LPS-stimulated MECs (P < 0.05). The mRNA expression of TLR4, MyD88, TRAF-6, IκB, and NIK was also significantly decreased when the LPS-stimulated MECs were cocultured at appropriate concentrations of JYT (P < 0.05, P < 0.01). Conclusion: These observations indicate a potential mechanism through which JYT attenuates the systemic inflammatory response to LPS-stimulated mouse mammary epithelial cells by inhibiting the activation of TLR4/MyD88/ TRAF-6/NIK pathway at the mRNA level.


2019 ◽  
Vol 20 (3) ◽  
pp. 600 ◽  
Author(s):  
Fengge Wang ◽  
Yun Zhao ◽  
Shuxiong Chen ◽  
Lu Chen ◽  
Liting Sun ◽  
...  

Ammonia is one of the major toxic components of metabolites in blood and tissues of high-producing dairy cows and could affect the health of bovine mammary glands. Bovine mammary epithelial cells are sensitive to oxidative stress induced by intensive cell metabolism. In our previous study, we found that ammonia could induce oxidative stress, apoptosis and inflammatory responses in bovine mammary epithelial cells. In the present study, the cytoprotective effects of astragaloside IV against ammonia in vitro were explored. The results demonstrated that pretreatment of MAC-T cells with astragaloside IV could potently suppress the increase in the level of intracellular reactive oxygen species (ROS) and the rate of cell apoptosis, inhibit the ammonia-induced inflammatory responses, and rescue the decrease of cell viability. Astragaloside IV prevented ammonia-induced endoplasmic reticulum stress. Astragaloside IV also significantly suppressed the levels of BAX, caspase 3 and p53 phosphorylation in ammonia-induced MAC-T cells. Nuclear factor erythroid 2-related factor 2(Nrf2) was essential for cytoprotective effects of astragaloside IV in MAC-T cells, as knockdown of Nrf2 dramatically abolished the prosurvival effects of astragaloside IV on treated cells. Furthermore, the PI3K/AKT and ERK/MAPK pathways were responsible for the induction of Nrf2 by astragaloside IV. In conclusion, astragaloside IV played a beneficial role against ammonia-induced damage of MAC-T cells. This provides a cue for future study to use astragaloside IV as a protective and curative agent against ammonia exposure of mammary glands in dairy cows.


2020 ◽  
pp. 1-7
Author(s):  
Jianfa Wang ◽  
Shuai Lian ◽  
Jun Song ◽  
Hai Wang ◽  
Xu Zhang ◽  
...  

Abstract Lipopolysaccharides (LPS) could induce milk fat depression via regulating the body and blood fat metabolism. However, it is not completely clear how LPS might regulate triglyceride synthesis in dairy cow mammary epithelial cells (DCMECs). DCMECs were isolated and purified from dairy cow mammary tissue and treated with LPS. The level of triglyceride synthesis, the expression and activity of the liver X receptor α (LXRα), enzymes related to de novo fatty acid synthesis, and the expression of the fatty acid transporters were investigated. We found that LPS decreased the level of triglyceride synthesis via a down-regulation of the transcription, translation, and nuclear translocation level of the LXRα. The results also indicated that the transcription level of the LXRα target genes, sterol regulatory element binding protein 1 (SREBP1), fatty acid synthetase (FAS), acetyl-CoA carboxylase-1 (ACC1), were significantly down-regulated in DCMECs after LPS treatment. Our data may provide new insight into the mechanisms of milk fat depression caused by LPS.


Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3194
Author(s):  
Yutaka Suzuki ◽  
Sachi Chiba ◽  
Koki Nishihara ◽  
Keiichi Nakajima ◽  
Akihiko Hagino ◽  
...  

Epithelial barrier function in the mammary gland acts as a forefront of the defense mechanism against mastitis, which is widespread and a major disorder in dairy production. Chemerin is a chemoattractant protein with potent antimicrobial ability, but its role in the mammary gland remains unelucidated. The aim of this study was to determine the function of chemerin in mammary epithelial tissue of dairy cows in lactation or dry-off periods. Mammary epithelial cells produced chemerin protein, and secreted chemerin was detected in milk samples. Chemerin treatment promoted the proliferation of cultured bovine mammary epithelial cells and protected the integrity of the epithelial cell layer from hydrogen peroxide (H2O2)-induced damage. Meanwhile, chemerin levels were higher in mammary tissue with mastitis. Tumor necrosis factor alpha (TNF-α) strongly upregulated the expression of the chemerin-coding gene (RARRES2) in mammary epithelial cells. Therefore, chemerin was suggested to support mammary epithelial cell growth and epithelial barrier function and to be regulated by inflammatory stimuli. Our results may indicate chemerin as a novel therapeutic target for diseases in the bovine mammary gland.


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.


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