Bombyxin-stimulated ecdysteroidogenesis in relation to sugar transporter/trehalase expressions in Bombyx prothoracic glands. (December 2022)

• Record Type: Journal Article
• Authors: Gu, Shi-Hong; Chang, Chia-Hao; Lin, Pei-Ling
• Is Part Of: Insect biochemistry and molecular biology. Volume 151(2022)
• Publication Date: 2022-12
• Subjects: Bombyx mori -- Insulin signaling -- Glycolytic rate -- Sugar transporter -- Treh -- PI3K -- 2-DG -- Aerobic glycolysis -- LDH -- Metabolism; Insect biochemistry -- Periodicals; Insects -- Physiology -- Periodicals; Insects -- Molecular aspects -- Periodicals; Biochemistry -- Periodicals; Insectes -- Biochimie -- Périodiques; Insectes -- Composition -- Périodiques; Insectes -- Physiologie -- Périodiques; Insectes -- Aspect moléculaire -- Périodiques; Biochimie -- Périodiques; Biochemistry; Insect biochemistry; Insects -- Molecular aspects; Insects -- Physiology; Periodicals; 572.8157
• DOI: 10.1016/j.ibmb.2022.103864
• Languages: English
• ISSNs: 0965-1748

Abstract

Abstract: Our previous studies showed that bombyxin stimulated ecdysteroidogenesis in Bombyx mori prothoracic glands (PGs) during a long-term incubation period in a phosphatidylinositol 3-kinase (PI3K)/Akt-dependent manner. In the present study, we further investigated the downstream signaling cascade in bombyxin-stimulated PGs. Our results showed that upon treatment with bombyxin, expression levels of the sugar transport 1 ( St1 ) and St4 genes and trehalase 1 ( Treh1 ) gene, but not ecdysteroid biosynthesis genes were greatly enhanced compared to the controls. Treatment with LY294002 (an inhibitor of PI3K) reduced the enhanced St1 and Treh1 expression levels, clearly indicating the involvement of PI3K. Treatment with 1 mM of mpV(pic) (a potent inhibitor of protein phosphotyrosine phosphatase and activator of insulin receptor (InR) kinase) also stimulated expression levels of the St1 and Treh1 genes, thus further confirming the involvement of the InR. Determining Treh enzyme activity showed that bombyxin treatment stimulated Treh enzyme activity in time- and PI3K-dependent manners. Validamycin A (a Treh inhibitor) blocked bombyxin-stimulated Treh enzyme activity and partly decreased bombyxin-stimulated ecdysteroidogenesis. A specific sugar transport inhibitor (cytochalasin B) and a glycolysis inhibitor (2-deoxy-D-glucose (2-DG)) also reduced bombyxin-stimulated ecdysteroidogenesis. Taken together, these results indicated that increased expressions of Sts and Treh1 and enhanced Treh enzyme activity downstream of InR/PI3K are involved in bombyxin-stimulated ecdysteroidogenesis in B. mori PGs. Graphical abstract: Image 1 Highlights: Bombyxin treatment increased St and Treh1 gene expression levels in PGs. Enhanced Treh enzyme activity was detected in bombyxin-treated PGs. Bombyxin-stimulated ecdysone secretion was inhibited by reducing sugar metabolism. PI3K-mediated sugar metabolism is likely involved in bombyxin-stimulated ecdysteroidogenesis in PGs.