Bombyx mori cathepsin D expression is induced by high temperature and H2O2 exposure

Cathepsin D is involved in the metamorphosis of the silkworm, Bombyx mori. Here, we show the expression profile of B. mori cathepsin D (BmCatD) in the fat body during exposure to stressors, such as high temperature and H2O2. Exposure of larvae in the fifth instar stage to high temperature (28 °C) led to accelerated metamorphosis and shortened larval stage compared to control larvae grown at 23 °C. Concomitantly, the expression level of BmCatD mRNA was greatly increased during exposure to high temperature. We also detected significantly elevated H2O2 levels in the hemolymph of larvae treated with high temperature. To confirm that oxidative stress induces BmCatD expression, B. mori larvae were injected with H2O2. As predicted, we observed increased expression of BmCatD following H2O2 exposure. Based on these results, we conclude that BmCatD expression is induced by high temperature and H2O2 exposure and that this stress-induced BmCatD expression leads to early metamorphosis.

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► BmCatD expression is induced by high temperature and H2O2 exposure.
► Stress-induced BmCatD expression in response to high temperature and oxidative stress leads to early metamorphosis.