Interaction between s. aureus and bovine mammary epithelial cells

点击翻译按钮获取中文摘要

In the dairy industry, mastitis is a most costly disease that causes significant losses in economics and milk production. As well, mastitis is an animal welfare issue and use of antibiotics to treat mastitis could be a concern for food safety. While many bacteria can cause bovine mastitis, one of the major causes is Staphylococcus aureus. S. aureus mastitis is contagious and extremely difficult to control because it usually develops into a chronic infection, due to their ability to adhere, invade, and persist in mammary epithelial cells. S. aureus strains from intramammary infection produce several cell surface-associated products. The exact pathogenic roles of most of the products and their effects on adhesion and invasion are not well evaluated. It is also known that mammary epithelial cell-associated molecules  interact with S. aureus during the pathogenesis of mastitis, but their roles on adhesion and invasion have not been characterized. The global objective of this proposed research is to use ClfA, a surface protein on S. aureus,  as a model system to study the mechanisms by which surface adhesins of S. aureus attach to and invade bovine mammary epithelial cells and how epithelial cells respond to the infection. Specifically, this proposed study aims to answer the following questions: how does the varying length of the repeats in ClfA from different strains of S. aureus affect the binding to epithelial cells? How do the different culture conditions affect the expression of repeats? Does ClfA link the bacteria and host epithelial cells through other proteins or as a ligand to the epithelial cell receptors? Is it possible to identify and isolate the receptors on bovine epithelial cells? How does gene expression change in both S. aureus and bovine epithelial cells during their interactions? Results from this proposed study will shed light on pathogenic mechanisms of S. aureus and consequently provide new strategies for a better prevention and therapy program.