There are two objectives of the ongoing research in my lab. Our first goal is to understand the process of follicle selection and development in the hen. The features of avian follicle development make the hen an ideal model for understanding the process of regulation of follicular recruitment. It is possible to study the production of a specific hormone by an individual follicle. We have studied the ovarian hormones inhibin, activin and anti-mullerian hormone as well as the oocyte-specific factor, GDF9. By understanding the interaction of the somatic cells and the oocyte in a species in which preovulatory development is so ordered and predictable, it may be possible to generalize these findings to other domestic animal species as well. A fundamental understanding of follicular recruitment is essential to maximizing reproductive efficiency, especially in turkeys and broiler breeder hens where egg production is not optimal. Our second research goal relates to the development and characterization of the chicken as a model for human ovarian cancer. There is no animal model, other than the hen, which spontaneously develops ovarian cancer with a high incidence. Previous studies, as well as our own data, show that hens develop ovarian cancer with a striking similarity to that found in human females. The main cause of the lethality of ovarian cancer in women is the fact that it is usually diagnosed at an advanced stage. The availability of an animal model will increase the chance of finding a marker for early diagnosis. In addition, an animal model will permit the testing of pharmaceuticals that may decrease the growth of this cancer. Finally, selected genomic analysis of hens with and without the disease may reveal a difference that underlies differential susceptibility to ovarian cancer.
Awards and Honors
- AAAS Fellow (2013) AAAS
- Johnson, P. A., Stephens, C. S., & Giles, J. (2015). The Domestic Chicken: Causes and Consequences of an Egg a Day. Poultry Science.
- Tiwari, A., Ocon-Grove, O., Hadley, J., Giles, J., Johnson, P. A., & Ramachandran, R. (2015). Expression of adiponectin and its receptors is altered in epithelial ovarian tumors and ascites-derived ovarian cancer cell lines. International journal of gynecological cancer : official journal of the International Gynecological Cancer Society. 25:399-406.
- Johnson, P. A., & Giles, J. (2013). The hen as a model of ovarian cancer. Nature Reviews Cancer. 13:432-436.
- Johnson, P. A. (2012). Follicle selection in the avian ovary. Reproduction in domestic animals = Zuchthygiene. 47:93-99.
- Wojtusik, J., & Johnson, P. A. (2012). Vitamin D regulates anti-mullerian hormone expression in granulosa cells of the hen. Biology of Reproduction. Biology of Reproduction. 86:2306-2315.
- Trevino, L. S., Buckles, E. L., & Johnson, P. A. (2012). Oral contraceptives decrease the prevalence of ovarian cancer in the hen. Cancer Prevention Research. 5:343-349.
- Giles, J., Stephens, C. S., & Johnson, P. A. Effects of Long-term Dietary Aspirin Treatment on Ovarian Cancer in the Hen [abstract]. 2014; Biology of Reproduction;.
- Stephens, C. S., & Johnson, P. A. Occludin expression regulates yolk accumulation in broiler hens [abstract]. 2014; Poultry Science Annual Meeting;.
- Stephens, C. S., & Johnson, P. A. Bone Morphogenetic Protein 15 Regulates Follicle Selection in the Hen [abstract]. 2013; Biology of Reproduction;.
- Stice, C. E., Trevino, L. S., & Johnson, P. A. Global gene expression of the hen ovary in response to different feeding conditions [abstract]. Biology of Reproduction, Special Issue; 2011;.
Presentations and Activities
- The Domestic Chicken: Causes and Consequences of an Egg a Day. Poultry Science Assn. 2014. Corpus Christi, TX.