Submitted to: Insect Biochemistry and Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2007
Publication Date: 1/4/2008
Citation: Stanley, D.W., Goodman, C.L., An, S., Mcintosh, A.H., Song, Q. 2008. Prostaglandins A2 and E1 influence gene expression in an established insect cell line (BCIRL-HzAM-1 cells). Insect Biochemistry and Molecular Biology. 38:275-284. Interpretive Summary: Application of classical insecticides has introduced severe problems in agricultural sustainability. The concept of biological control of insects is a potentially powerful alternative to classical insecticides. Biological control is based on the idea that direct application of insect-specific pathogens and parasites can reduce pest insect populations and the economic damage due to pest insects. The problem, however, is the efficiency of these organisms in biological control programs is limited by insect immune defense reactions to challenge. One approach to improving the efficiency of biocontrol agents would be to somehow disable insect immune reactions to viral, bacterial, fungal and parasitic infections. With this goal, we are investigating how insect immune reactions to infection are signaled. In this paper we report on identification of biological signals that are responsible for stimulating insect defenses to infection. We show for the first time that these signals work by influencing insect gene expression. This new research will be directly useful to scientists who are working to improve the efficacy of biological control methods. The ensuing improved biological control methods will benefit a wide range of agricultural producers by supporting the long-term sustainability of agriculture.
Technical Abstract: PGs and other eicosanoids exert important physiological actions in insects and other invertebrates, including influencing ion transport and mediating cellular immune defense functions. Although these actions are very well documented, we have no information on the mechanisms PGs action in insect cells. Here we report on the outcomes of experiments designed to test our hypothesis that prostaglandins (PGs) modulate gene expression in an insect cell line established from pupal ovarian tissue of the moth Helicoverpa zea (BCIRL-AMHz1 cells). We treated cells with either PGA1 or PGE1 for 12 or 24 hr then analyzed cell lysates by 2-D electrophoresis. Analysis of the gels by densitometry revealed substantial changes in protein expression in 36 of the ~500 visible protein spots. These spots were processed for mass spectrometric analysis by MALDI TOF/TOF, which yielded putative protein identities for all 36 spots. The apparent changes in three of the proteins were confirmed by semi-quantitative PCR, showing that the changes in protein expression were reflected in changes in mRNA. The 36 proteins were sorted into six categories, Protein Actions, Lipid Metabolism, Signal Transduction, Protection, Cell Functions, and Metabolism. The findings support the hypothesis that one mechanism of PG action in insect cells is through modulation of gene expression.