The role of native bovine α-lactalbumin in bovine mammary epithelial cell apoptosis and casein expression

2008 ◽  
Vol 75 (3) ◽  
pp. 319-325 ◽  
Author(s):  
Lisa G Riley ◽  
Peter C Wynn ◽  
Peter Williamson ◽  
Paul A Sheehy

Folding variants of α-lactalbumin (α-la) are known to induce cell death in a number of cell types, including mammary epithelial cells (MEC). The native conformation of α-la however has not been observed to exhibit this biological activity. Here we report that native bovine α-la reduced the viability of primary bovine mammary epithelial cells (BMEC) and induced caspase activity in mammospheres, which are alveolar-like structures formed by culturing primary BMEC on extracellular matrix in the presence of lactogenic hormones. These observations suggest a possible role for bovine α-la in involution and/or maintaining the luminal space in mammary alveoli during lactation. In addition, co-incubation of bovine α-la in an in-vitro mammosphere model resulted in decreased β-casein mRNA expression and increased αs1- and κ-casein mRNA expression. This differential effect on casein expression levels is unusual and raises the possibility of manipulating expression levels of individual caseins to alter dairy processing properties. Manipulation of α-la levels could be further investigated for its potential to enhance milk protein expression and/or improve lactational persistency by influencing the balance between proliferation and apoptosis of BMEC, which has a major influence on the milk-producing capacity of the mammary gland.

2021 ◽  
Vol 22 (12) ◽  
pp. 6254
Author(s):  
Ting Li ◽  
Changjie Lin ◽  
Yifan Zhu ◽  
Haojun Xu ◽  
Yiya Yin ◽  
...  

Mastitis is a common disease in dairy cows that is mostly caused by E. coli, and it brings massive losses to the dairy industry. N6-Methyladenosine (m6A), a methylation at the N6 position of RNA adenine, is a type of modification strongly associated with many diseases. However, the role of m6A in mastitis has not been investigated. In this study, we used MeRIP-seq to sequence the RNA of bovine mammary epithelial cells treated with inactivated E. coli for 24 h. In this in vitro infection model, there were 16,691 m6A peaks within 7066 mRNA transcripts in the Con group and 10,029 peaks within 4891 transcripts in the E. coli group. Compared with the Con group, 474 mRNAs were hypermethylated and 2101 mRNAs were hypomethylated in the E. coli group. Biological function analyses revealed differential m6A-modified genes mainly enriched in the MAPK, NF-κB, and TGF-β signaling pathways. In order to explore the relationship between m6A and mRNA expression, combined MeRIP-seq and mRNA-seq analyses revealed 212 genes with concomitant changes in the mRNA expression and m6A modification. This study is the first to present a map of RNA m6A modification in mastitis treated with E. coli, providing a basis for future research.


2019 ◽  
Vol 86 (2) ◽  
pp. 177-180
Author(s):  
Jacqueline P. Kurz ◽  
Mark P. Richards ◽  
Matthew Garcia ◽  
Zhongde Wang

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Nayeli Alva-Murillo ◽  
Alejandra Ochoa-Zarzosa ◽  
Joel E. López-Meza

Bovine mammary epithelial cells (bMECs) are capable of initiating an innate immune response to invading bacteria. Short chain fatty acids can reduceStaphylococcus aureusinternalization into bMEC, but it has not been evaluated if octanoic acid (sodium octanoate, NaO), a medium chain fatty acid (MCFA), has similar effects. In this study we determined the effect of NaO onS. aureusinternalization into bMEC and on the modulation of innate immune elements. NaO (0.25–2 mM) did not affectS. aureusgrowth and bMEC viability, but it differentially modulated bacterial internalization into bMEC, which was induced at 0.25–0.5 mM (~60%) but inhibited at 1-2 mM (~40%). Also, bMEC showed a basal expression of all the innate immune genes evaluated, which were induced byS. aureus. NaO induced BNBD4, LAP, and BNBD10 mRNA expression, but BNBD5 and TNF-αwere inhibited. Additionally, the pretreatment of bMEC with NaO inhibited the mRNA expression induction generated by bacteria which coincides with the increase in internalization; only TAP and BNDB10 showed an increase in their expression; it coincides with the greatest effect on the reduction of bacterial internalization. In conclusion, NaO exerts a dual effect onS. aureusinternalization in bMEC and modulates elements of innate immune response.


2016 ◽  
Vol 96 (4) ◽  
pp. 478-487
Author(s):  
Cuiping Yu ◽  
Chaochao Luo ◽  
Xinyu Gu ◽  
Yanli Zang ◽  
Bo Qu ◽  
...  

The 14-3-3γ protein participates in many biological processes; however, its regulatory mechanism in milk protein synthesis is not well studied. We hypothesized that 14-3-3γ might affect eIF5 (an initiation factor) to regulate β-casein synthesis in dairy cows. In this study, a possible interaction between 14-3-3γ and eIF5 was investigated using bovine mammary epithelial cells (BMECs). The expression levels of 14-3-3γ and eIF5 in the mammary gland tissues from cows producing higher quality milk were higher than those from cows producing low-quality milk. Moreover, the expression of 14-3-3γ, eIF5, and β-casein were increased at both mRNA and protein levels in BMECs cultured in vitro with methionine (Met) supplementation. Coimmunoprecipitation, colocalization, and FRET analysis further showed the evidences that 14-3-3γ physically bound to eIF5 in BMECs. Gene function studies revealed that 14-3-3γ positively regulated eIF5 through alteration of eIF2α/p-eIF2α ratio. Collectively, our data suggest that 14-3-3γ regulates β-casein translation in BMECs through interaction with eIF5.


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