Cathepsin L participates in the remodeling of the midgut through dissociation of midgut cells and activation of apoptosis via caspase-1.
The larval midgut in holometabolous insects must undergo a remodeling process during metamorphosis to form the pupal-adult midgut. However, the molecular mechanism of larval midgut cell dissociation remains unknown. Here, we show that the expression and activity of Helicoverpa armigera cathepsin L (Har-CatL) are high in the midgut at the mid-late stage of the 6th-instar larvae and are responsive to the upstream hormone ecdysone. Immunocytochemistry shows that signals for Har-CatL-like are localized in midgut cells, and an inhibitor experiment demonstrates that Har-CatL functions in the dissociation of midgut epithelial cells. Mechanistically, Har-CatL can cleave pro-caspase-1 into the mature peptide, thereby increasing the activity of caspase-1, which plays a key role in apoptosis, indicating that Har-CatL is also involved in the apoptosis of midgut cells by activating caspase-1. We believe that this is the first report that Har-CatL regulates the dissociation and apoptosis of the larval midgut epithelium for midgut remodeling.
State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.
Cui
C
Yang
State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.
Xian-Wu
XW
Lin
State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China. Electronic address: xuweihua@mail.sysu.edu.cn.
Wei-Hua
WH
Xu
D000818:Animals; D017209:Apoptosis; D020170:Caspase 1 / Q000378:metabolism*; D056668:Cathepsin L / Q000502:physiology*; D002460:Cell Line; D004440:Ecdysone / Q000378:metabolism; D004441:Ecdysterone; D041981:Gastrointestinal Tract / Q000502:physiology; D007814:Larva / Q000201:enzymology; D008675:Metamorphosis, Biological; D009036:Moths / Q000502:physiology*
D004440:Ecdysone; D004441:Ecdysterone; D056668:Cathepsin L; D020170:Caspase 1
Apoptosis; Caspase-1; Cathepsin L; Ecdysone; Helicoverpa armigera; Midgut degradation