PhD from Michigan State University
Graduate fields: Animal Science, Nutrition, Food Science and Technology
Area(s) of interest: Functional genomics of mineral-dependent enzymes in antioxidation, diabetes, obesity, and bone integrity in mice, pigs, and primary cells; overexpression and protein engineering of phytases and proteases for nutrition and environmental protection; using pigs as a human model and biofortification to fight against global micro-nutrient deficiencies in humans
Teaching:
- Animal Science and Society: From Food to Medicine-AS 1160
- Animals in Biomedical Research-AS 3980
- Mineral Nutrition: Metabolic, Health, & Environmental Aspects - AS/NS 6030
- American Society for Nutrition (Associate Editor of Journal of Nutrition)
- American Society of Animal Science
- American Society of Microbiology
- American Association for the Advancement of Science
- Experimental Biology and Medicine
- Cornell Institute of Food Science
- British Biochemical Society
- Chinese Oversea Biologist Society
- Chinese American Diabetes Society
- Chinese Association of Young Scientists and Technologists
- Trace Elements in Man and Animals (TEAM, parent committee,
Chair of the 14th TEMA, http://www.rowett.ac.uk/tema) - HarvestPlus-China Program (Associate Director,
http://www.harvestplus-china.org/english/swqh/swqh.htm) - International Center of Future Agriculture for Human Health
(Director, http://ww1.sicau.edu.cn/icfahh)
Website(s): Lei Laboratory
Current Research:
The Lei Laboratory is located in Morrison Hall.
Selenium, copper, and zinc are essential trace elements for animals and humans. However, in vivo functions of these elements in metabolism and disease are still unclear. Cellular glutathione peroxidase (GPX1) is the first identified and the most abundant selenium-dependent enzyme in mammals. Copper,zinc-superoxide dismutase (SOD1) is considered to be another major cyotosolic antioxidant enzyme. Using GPX1 and SOD1 single or double knockout mice, we have previously illustrated a dual role of these enzymes. Both protect against oxidative stresses initiated by reactive oxygen species, but appear to promote the stress initiated by reactive nitrogen species. Most intriguingly, we have demonstrated that overexpression of GPX1 induces metabolic syndrome in mice and hyperinsulinemia is the primary effect of transgene. Currently, we are using these animal models and their islets to study the molecular mechanism and signal pathway for the regulation of GPX1 and SOD1 in insulin synthesis, secretion, and function. Experimental approaches include microarray, real-time PCR, proteomics, and co-immunoprecipitation for protein and protein interaction. Future development of large animal models and human clinical investigations are under planning.
Environmental pollution of excess phosphorus (P) and nitrogen (N) in animal waste, especially from swine and poultry, is a serious problem that animal agriculture faces today. This mainly originates from the inefficiency of these simple-stomached animals to utilize phytate-P and plant protein in the commonly used feedstuff. Meanwhile, supplementing inorganic P and high-quality protein source in animal feed accelerates the depletion of the limited natural deposit or competes against human consumption. Our laboratory has previously developed a new generation of bacterial phytase (AppA2) that is being used by swine and poultry producers worldwide. The enzyme effectively improves phytate-P utilization by animals, obviates the need for addition of inorganic phosphorus, and decreases their P excretion by 50%. Currently, we are studying the potential application of this phytase in improving bone health of animals and humans while further optimizing its function by protein engineering. In collaboration with a Chinese research group, we are applying genomic and proteomic tools to explore the key enzymes produced by a feather-degrading bacterium. We hope that an enzyme complex will be identified from this organism that could be used to degrade the enormous amount of unutilized feather protein into soluble peptides or amino acid for animal feeding.
Up to 50% of the world population suffers from iron, zinc, and(or) vitamin A deficiencies. Low intake and poor bioavailability of these nutrients in staple crops are the main cause of the problem. These deficiencies have presented high health, economic, and social costs to the world. Food fortification has been effective in the developed countries, but not feasible or sustainable in developing countries. Thus, an international program called HarvestPlus (http://www.harvestplus.org) has been established to breed crops for better nutrition. Our laboratory has joined a Cornell/USDA research team and used pigs as a model to study plant enhancers (inulun) of iron nutrition. Meanwhile, I have also helped in establishing a sister-program called HarvestPlus-China program (http://www.harvestplus-china.org/english/swqh/swqh.htm) and leading 80 Chinese and international plant, soil, food, animal, and nutrition scientists and economists to improve iron and vitamin A nutrition of four staple crops (rice, corn, wheat, and sweet potato) in China. I have also helped in establishing an international center of Future Agriculture for Human Health at Sichuan Agriculture University (http://ww1.sicau.edu.cn/icfahh) and am serving as the founding Director. The center is applying genomic, molecular, and proteomic techniques to study physiological functions and health implications of plant, animal, and microbial foods. The center will attempt to develop new generation of health value-added foods for the general public.