A comparative analysis of corpora allata-corpora cardiaca microRNA repertoires revealed significant changes during mosquito metamorphosis

Abstract

The corpora allata (CA) are a pair of endocrine glands with neural connections to the brain and close association with another neuroendocrine organ, the corpora cardiaca (CC). The CA from adult female Aedes aegypti mosquitoes synthesize fluctuating levels of juvenile hormone (JH), which have been linked to the ovarian development and are influenced by nutritional signals. In this study, we investigated the potential involvement of microRNAs (miRNAs), a type of small non-coding RNAs, in the regulation of gene expression in CA-CC complexes during mosquito reproductive development, at stages with distinct JH biosynthesis patterns. We analyzed the miRNA repertoires expressed in the CA-CC of pupae, sugar-fed and blood-fed female Ae. aegypti. In total, 156 mature miRNAs were detected in the CA-CC, with 84 displaying significant differences in expression among the three CA-CC developmental stages. There were more miRNAs that were expressed in pupae, and decreased or were absent after adult emergence, when compared with changes between CA-CC of sugar and blood-fed females. Analysis of the genes identified as potential targets for the CA-CC miRNA repertoires classified them into the broad categories of metabolism, information storage and processing, and cellular processes and signaling; with genes involved in cellular processes and signaling representing the largest portion. Among them, the signal-transduction mechanisms and intracellular trafficking, secretion and vesicular transport contained almost 55% of the genes' targets. A substantial number of miRNAs were differentially abundant in the libraries of the three developmental stages, and those changes were much more notable when pupae and adult stages were compared. We detected putative binding sites for some of the most abundant miRNAs on genes encoding JH biosynthetic enzymes and CC neuropeptides. These studies should help us to gain a better understanding of the regulation of CA-CC activity mediated by miRNAs during major developmental stages in mosquitoes.

Diversity of Insect Sesquiterpenoid Regulation

“…In many insects, miRNAs have also been found to potentially regulate different sesquiterpenoid pathway genes ( Table 2 ). For instances, in mosquito A. aegypti , four JH biosynthetic enzyme genes including 3-hydroxy-3-methylglutaryl-coenzyme A reductase ( HMGR ), diphosphomevalonate decarboxylase ( PP-MevD ), aldehyde dehydrogenase ( ALDH ), and farnesyl-pyrophosphate synthase ( FPPS ) were in silico predicted to be potentially regulated by miRNAs ( Nouzova et al, 2018 ). In addition, in the adult female mosquito, mosquito specific miR-1890 targets JH-controlled chymotrypsin-like SP, JHA15 that involve in the regulation of blood digestion, ovary development and egg deposition ( Lucas et al, 2015 ).…”

Expression Dynamics of Core RNAi Machinery Genes in Pea Aphids Upon Exposure to Artificially Synthesized dsRNA and miRNAs

“…RT-qPCR was performed on a BIO-RAD CFX Connect Real-Time System using a miRNA RT-qPCR assay kit (Tiangen, Beijing, China). The mature miR-3024 gene sequence was used as the forward primer and the U6 snRNA was used as a reference [41] (Table S1). The reactions were performed in a 20 µL volume of a mixture containing 1 µL 2×miRNA RT-qPCR mix, 1 µL cDNA template, 0.4 µL of each primer, and 8.2 µL of nuclease-free water.…”

Two Undervalued Functions of the Golgi Apparatus: Removal of Excess Ca2+ and Biosynthesis of Farnesol-Like Sesquiterpenoids, Possibly as Ca2+-Pump Agonists and Membrane “Fluidizers–Plasticizers”

“…In contrast, in insects, it started with the pioneering work of Kopec (1922) about a century ago, with his discovery that the insect brain is an endocrine gland. Later, key pioneers were sir Vincent Wigglesworth with his discovery of JH synthesized by the CA, and Carroll M. Williams with the serendipitous discovery that the abdomen of male Hyalophora cecropia moths was a repository of high amounts of JH (references in Riddiford, 1994;Watt and Davey, 1996;Nijhout, 1998). It took many years before it became clear that the CA were not the only site of synthesis of farnesol/JHs.…”

“…Later research showed that it is a much more complex issue and that sNPF plays, among other functions, a prominent role in the control of feeding (Carlson et al, 2013;Fadda et al, 2019). In addition, changes in microRNAs may also play a role (Nouzova et al, 2018a).…”