Calcium influx enhances neuropeptide activation of ecdysteroid hormone production by mosquito ovaries

Autor(es): McKinney, David A.; Eum, Jai-Hoon; Dhara, Animesh; Strand, Michael R.; Brown, Mark R.


Resumo: A critical step in mosquito reproduction is the ingestion of a blood meal from a vertebrate host. In mosquitoes like Aedes aegypti, blood feeding stimulates the release of ovary ecdysteroidogenic hormone (OEH) and insulin-like peptide 3 (ILP3). This induces the ovaries to produce ecdysteroid hormone (ECD), which then drives egg maturation. In many immature insects, prothoracicotropic hormone (PITH) stimulates the prothoracic glands to produce ECD that directs molting and metamorphosis. The receptors for OEH, ILP3 and PITH are different receptor tyrosine kinases with OEH and ILP3 signaling converging downstream in the insulin pathway and PITH activating the mitogen-activated protein kinase pathway. Calcium (Ca2+) flux and CAMP have also been implicated in PTTH signaling, but the role of Ca2+ in OEH, ILP3, and cAMP signaling in ovaries is unknown. Here, we assessed whether Ca2+ flux affects OEH, ILP3, and cAMP activity in A. aegypti ovaries and also asked whether PTTH stimulated ovaries to produce ECD. Results indicated that Ca2+ flux enhanced but was not essential for OEH or ILP3 activity, whereas CAMP signaling was dependent on Ca2+ flux. Recombinant PTTH from Bombyx mori fully activated ECD production by B. mori PTGs, but exhibited no activity toward A. aegypti ovaries. Recombinant PTTH from A. aegypti also failed to stimulate either B. mori PTGs or A. aegypti ovaries to produce ECD. We discuss the implications of these results in the context of mosquito reproduction and ECD biosynthesis by insects generally. (C) 2016 Elsevier Ltd. All rights reserved.


Palavras-Chave: Ovary ecdysteroidogenic hormone; Insulin-like peptide; Prothoracicotropic hormone; Prothoracic gland; Bombyx mori; Aedes aegypti


Imprenta: Insect Biochemistry and Molecular Biology, v. 70, p. 160-169, 2016


Identificador do objeto digital: 10.1016/j.ibmb.2016.01.001


Descritores: Aedes aegypti - Biosynthesis ; Aedes aegypti - Protein synthesis


Data de publicação: 2016