|De Wilde, Daan|
Submitted to: Annals of the New York Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2005
Publication Date: 4/20/2005
Citation: Smagghe, G., Vanhassel, W., Moeremans, C., De Wilde, D., Goto, S., Loeb, M.J., Blackburn, M.B., Hakim, R.S. 2005. Stimulation of midgut stem cell proliferation and differentiation by insect hormones and peptides.. Annals Of The New York Academy Of Sciences. 1040: 472-475 Interpretive Summary: If it were possible to interfere with the normal growth and healing mechanisms of the insect gut, biological control agents that attack the insect through the gut, such as bacteria and viruses, could be made more effective. Unfortunately, little is known about these mechanisms. In order to better understand how the insect's gut grows and heals, we applied the molting hormone of insects, which controls the skin-shedding cycles insects must go through to grow, and the biochemical precursor of the molting hormone to stem cells from the insect gut. Stem cells are undeveloped cells that multiply and then develop into fully mature cell types, allowing tissues to grow and repair themselves. Using gut stem cells from the cotton leafworm, it was discovered that the precursor of the molting hormone was more effective at stimulating the stem cells to multiply, while the molting hormone itself was more effective at stimulating the stem cells to develop into mature gut cells. In addition, an abundant blood protein of insects, arylphorin, was found to stimulate stem cell multiplication. These results provide important clues about how the insect gut grows and repairs itself, and can be used by scientists who want to develop ways of interfering with insect gut development and healing mechanisms.
Technical Abstract: Stem cells derived from midguts of the caterpillar Spodoptera littoralis can be induced to multiply and differentiate in vitro. Both ecdysone and 20-hydroxyecdysone had concentration dependent effects on the stem cells, however, ecdysone was more active in stimulation of stem cell proliferation, while 20-hydroxyecdysone was more active in stimulating stem cell differentiation into mature gut cells. Ecdysteroid receptors were found in midgut stem cell nuclei using the antibody 9B9. In addition, alpha-arylphorin and four midgut differentiation factors specifically stimulated proliferation and differentiation of stem cells, respectively.