Current Research Focuses:

Milk is an important source of nutrients in most human diets. Milk produced by dairy cows generates more than 35 billion dollars each year in sales (about 9% of U.S. agriculture earnings).  During milk production, cows are more likely to get an infection of the udder called mastitis. This triggers an immune response and causes white blood cells (WBC) to travel to the infected udders.  While the white blood cells work to destroy the infection, they release byproducts called oxygen radicals that also damage the cells that produce milk within the udder. Because of this damage, infected udders produce less milk. In this project we will explore ways that the milk producing cells try to protect themselves from this damage.  In particular, we will study the function of a special defense protein called Nrf2.  Nrf2 is known to play a key role in removing oxygen radicals that develop in other conditions like aging and cancer in humans. If Nrf2 plays a similar role in the milk producing cells, we will look for ways to boost natural Nrf2 activity to better protect the udders during mastitis.  Overall, this study will improve our ability to prevent or reduce the damage caused by mastitis, and will have real-world implications for improving the production of high-quality milk by our national herd of dairy cows.

Supported by:

• USDA NIFA Animal Health Program

Current Collabrators:

• Dr. David Kerr, Department of Animal and Veterinary Sciences, University of Vermont, Burlington, VT, USA
• Drs. Hongyun Liu and Jianxin liu, Institute of Dairy Science, Zhejiang University, Hangzhou, China

Read more:

• Jin et al. (2016) Oxid Med Cell Longev, 2572175
• Jin et al. (2016) J Dairy Sci. 99(11):9094-9103

Main pathways of glucose utilization in mammary alveolar epithelial cells. In mammary epithelial cells, glucose is mainly used in 1) lactose synthesis in the Golgi, 2) energy production via glycolysis and the tricarboxylic acid cycle (TCA), 3) NADPH production via the pentose phosphate shunt, and 4-6) providing substrates for lipid (glycerol and fatty acid, 4), protein (nonessential amino acid, 5) and nucleic acid (ribose, 6) syntheses. Adapted from Zhao F-Q, (2014) J Mammary Gland Biol Neoplasia 19:3¨C17

Read more:

• Zhao F-Q.(2014) J Mammary Gland Biol Neoplasia 19:3¨C17
• Zhao F-Q, Keating AF. (2007) J Dairy Sci 90 (Suppl. 1), E76-E86
• Shao Y, Zhao, F-Q. (2014). J Anim Sci Biotech, 5,9

Glucose is the major precursor of lactose, which is synthesized in Golgi vesicles of mammary secretory alveolar epithelial cells (MECs) during lactation. Glucose is also utilized as an energy source and a substrate for lipid and protein synthesis in MECs (see the figure on the right). Glucose is taken up by MECs through facilitative glucose transporters (GLUTs). The increased GLUT expression during lactogenesis is not stimulated by the accepted lactogenic hormones. New evidence indicates that a possible low oxygen tension resulting from increased metabolic rate and oxygen consumption may play a major role in stimulating glucose uptake and GLUT1 expression in MECs during lactogenesis.Our aim is to investigate the mechanisms of regulation of glucose uptake and utilization in MECs during physiological and pathological conditions. Because lactose synthesis dictates milk volume, regulation of glucose uptake and metabolism represents potentially fruitful areas for further research in dairy production. In addition, this research will have pathological implications for the treatment of breast cancer because glucose uptake and GLUT expression are up-regulated in breast cancer cells to accommodate the increased glucose need.

Supported by:

• USDA NIFA Animal Nutrition, Growth and Lactation Program
• Vermont Agricultural Experiment Station

Current Collabrators:

• Dr. Dwight Matthews, Department of Chemsitry, University of Vermont
• Drs. Hongyun Liu and Jianxin liu, Institute of Dairy Science, Zhejiang University, Hangzhou, China