Hippo pathway regulates somatic development and cell proliferation of silkworm

Hippo signaling pathway (signaling pathway Hippo, hereinafter referred to as the Hippo pathway) was the earliest found in Drosophila (Schneck [1]), which can regulate the development of tissues and organs, even some components of the pathway were identified as tumor suppressor [2]. The pathway was more concerned in fruit flies and mice (Schneck [1]), but little attention has been given in silkworm, an important economic and lepidopteran model insect. In this manuscript, we identified major Hippo pathway related genes (Hippo, Salvador, Warts, Mats, Yorkie) in silkworm and named BmHpo, BmSav, BmWts, BmMats, BmYki. The domain organization of these genes was highly conserved in silkworm and other organisms suggesting that they could use similar protein-protein interactions to construct the Hippo kinase cascades. The expression profiles of these genes in silkworm during embryonic, larval, wandering, pupal and adult stages were analyzed, 14 tissues/organs of the day 3, 5th instar larvae (L5D3) as well. Experimental results showed that the expression of Hippo pathway had some influence on the development of silkworm. In order to find out the mechanism of Hippo pathway affecting silkworm development, BmHpo and BmYki were up-regulated and de-regulated in the cell line of Bombyx mori-BmN-SWU1(NS), and the changes of cell proliferation activity and cell cycle were detected. The distribution of BmYki was detected by immunofluorescence technique. This study provides insights into the genes of Hippo pathway which have a certain effect on somatic development and cell proliferation in silkworm.

HDAC inhibitor misprocesses bantam oncomiRNA, but stimulates hid induced apoptotic pathway

Apoptosis or programmed cell death is critical for embryogenesis and tissue homeostasis. Uncontrolled apoptosis leads to different human disorders including immunodeficiency, autoimmune disorder and cancer. Several small molecules that control apoptosis have been identified. Here, we have shown the functional role of triazole derivative (DCPTN-PT) that acts as a potent HDAC inhibitor and mis-express proto onco microRNA (miRNA) bantam. To further understanding the mechanism of action of the molecule in apoptotic pathway, a series of experiments were also performed in Drosophila, a well known model organism in which the nature of human apoptosis is very analogous. DCPTN-PT mis processes bantam microRNA and alters its down regulatory target hid function and cleavage of Caspase-3 which in turn influence components of the mitochondrial apoptotic pathway in Drosophila. However regulatory microRNAs in other pro-apoptotic genes are not altered. Simultaneously, treatment of same molecule also affects the mitochondrial regulatory pathway in human tumour cell lines suggesting its conservative nature between fly and human. It is reasonable to propose that triazole derivative (DCPTN-PT) controls bantam oncomiRNA and increases hid induced apoptosis and is also able to influence mitochondrial apoptotic pathway.