Bifunctional role of ephrin A1-Eph system in stimulating cell proliferation and protecting cells from cell death through the attenuation of ER stress and inflammatory responses in bovine mammary epithelial cells

Aflatoxin M1 (AFM1), a hydrogenated metabolite of aflatoxin B1 (AFB1), is one of the most common and threatening aflatoxins found in milk and dairy products. The ATP-binding cassette G2 efflux transporter (ABCG2) plays an important role in the mammary transport of drugs and toxins in animals, but whether ABCG2 could affect the transport of AFM1 in bovine mammary epithelial cells (BMECs) has not been clarified. Therefore, this study aimed to investigate the effects of AFM1 on tight junctions (TJs), lactation and cells proliferation in BMECs, and explored the regulatory role of ABCG2 in AFM1 transport in vitro in BMECs. The results showed that the integrity of the TJs of BMECs was not permanently compromised after exposure to AFM1. AFM1 exposure had no obvious effects on lactation or cell proliferation in BMECs. Gene function study revealed that ABCG2 was a positive regulator of AFM1 transport. These results demonstrate that it has little effect on TJs, lactation or cell proliferation in BMECs exposed to a small dose of AFM1, and ABCG2 is a critical regulator for AFM1 transport in BMECs.

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5-ALA Attenuates the Palmitic Acid-Induced ER Stress and Apoptosis in Bovine Mammary Epithelial Cells

Molecules ◽

10.3390/molecules26041183 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1183

Author(s):

Mst Mamuna Sharmin ◽

Md Aminul Islam ◽

Itsuki Yamamoto ◽

Shin Taniguchi ◽

Shinichi Yonekura

Keyword(s):

T Cells ◽

Epithelial Cells ◽

Palmitic Acid ◽

Er Stress ◽

Aminolevulinic Acid ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Protective Effects ◽

Bovine Mammary Epithelial Cells ◽

Induced Apoptosis

The conservation of mammary gland physiology by maintaining the maximum number of mammary epithelial cells (MECs) is of the utmost importance for the optimum amount of milk production. In a state of negative energy balance, palmitic acid (PA) reduces the number of bovine MECs. However, there is no effective strategy against PA-induced apoptosis of MECs. In the present study, 5-aminolevulinic acid (5-ALA) was established as a remedial agent against PA-induced apoptosis of MAC-T cells (an established line of bovine MECs). In PA-treated cells, the apoptosis-related genes BCL2 and BAX were down- and upregulated, respectively. The elevated expression of major genes of the unfolded protein response (UPR), such as CHOP, a proapoptotic marker (C/EBP homologous protein), reduced the viability of PA-treated MAC-T cells. In contrast, 5-ALA pretreatment increased and decreased BCL2 and BAX expression, respectively. Moreover, cleaved caspase-3 protein expression was significantly reduced in the 5-ALA-pretreated group in comparison with the PA group. The downregulation of major UPR-related genes, including CHOP, extended the viability of MAC-T cells pretreated with 5-ALA and also reduced the enhanced intensity of the PA-induced expression of phospho-protein kinase R-like ER kinase. Moreover, the enhanced expression of HO-1 (antioxidant gene heme oxygenase) by 5-ALA reduced PA-induced oxidative stress (OxS). HO-1 is not only protective against OxS but also effective against ER stress. Collectively, these findings offer new insights into the protective effects of 5-ALA against PA-induced apoptosis of bovine MECs.

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Exogenous phospholipase A2 affects inflammatory gene expression in primary bovine mammary epithelial cells

Journal of Dairy Research ◽

10.1017/s0022029919000232 ◽

2019 ◽

Vol 86 (2) ◽

pp. 177-180

Author(s):

Jacqueline P. Kurz ◽

Mark P. Richards ◽

Matthew Garcia ◽

Zhongde Wang

Keyword(s):

Epithelial Cells ◽

Phospholipase A2 ◽

Inflammatory Responses ◽

Mammary Epithelial Cells ◽

Constitutive Expression ◽

Mammary Epithelial ◽

Inflammatory Factors ◽

Bovine Mammary Epithelial Cells ◽

Lps Challenge

AbstractThis Research Communication addresses the hypothesis that exogenously administered phospholipase A2 (PLA2) affects the inflammatory responses of bovine mammary epithelial cells (bMEC) in vitro with the aim of providing preliminary justification of investigation into the uses of exogenously administered PLA2 to manage or treat bovine mastitis. Primary bMEC lines from 11 lactating Holstein dairy cows were established and the expression of 14 pro-inflammatory genes compared under unchallenged and lipopolysaccharide (LPS)-challenged conditions, with and without concurrent treatment with bovine pancreatic PLA2G1B, a secreted form of PLA2. No differences in the expression of these genes were noted between PLA2-treated and untreated bMEC under unchallenged conditions. Following LPS challenge, untreated bMEC exhibited significant downregulation of CXCL8, IL1B, CCL20, and CXCL1. In contrast, PLA2-treated bMEC exhibited significant downregulation of IL1B and CCL20 only. These findings indicate that exogenous PLA2 affects the expression of some pro-inflammatory factors in immune-stimulated bMEC, but does not influence the constitutive expression of these factors. Further investigation of the influence of exogenous PLA2 in the bovine mammary gland is justified.

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MiR-125b regulates inflammation in bovine mammary epithelial cells by targeting the NKIRAS2 gene

Veterinary Research ◽

10.1186/s13567-021-00992-0 ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Zhuo-Ma Luoreng ◽

Da-Wei Wei ◽

Xing-Ping Wang

Keyword(s):

T Cells ◽

Epithelial Cells ◽

Dairy Cows ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Luciferase Reporter ◽

Regulation Mechanism ◽

Bovine Mammary Epithelial Cells ◽

Tnf Α

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.

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