Identification and characterization of the adipokinetic hormone/corazonin‐related peptide signaling system in Rhodnius prolixus

Abstract

The mammalian gonadotropin‐releasing hormone is evolutionarily related to the arthropod adipokinetic hormone and the recently discovered adipokinetic hormone/corazonin‐related peptide (ACP). The function of the ACP signaling system in arthropods is currently unknown. In the present study, we identify and characterize the ACP signaling system in the kissing bug Rhodnius prolixus. We isolated the complete cDNA sequence encoding R. prolixus ACP (Rhopr‐ACP) and examined its expression pattern. Rhopr‐ACP is predominantly expressed in the central nervous system. In particular, it is found in both the brain and corpus cardiacum (CC)/corpora allata (CA) complex. To gain an insight into its role in R. prolixus, we also isolated and functionally characterized cDNA sequences of three splice variants (Rhopr‐ACPR‐A, B and C) encoding R. prolixus ACP G protein‐coupled receptor (Rhopr‐ACPR). Rhopr‐ACPR‐A has only five transmembrane domains, whereas Rhopr‐ACPR‐B and C have all seven domains. Interestingly, Rhopr‐ACPR‐A, B and C were all activated by Rhopr‐ACP, albeit at different sensitivities, when expressed in Chinese hamster ovary cells stably expressing the human G‐protein G16 (CHO/G16). To our knowledge, this is the first study to isolate a truncated receptor cDNA in invertebrates that is functional in a heterologous expression system. Moreover, Rhopr‐ACPR‐B and C but not Rhopr‐ACPR‐A can be coupled with Gq α subunits. Expression profiling indicates that Rhopr‐ACPR is highly expressed in the central nervous system, as well as the CC/CA complex, suggesting that it may control the release of other hormones found in the CC in a manner analogous to gonadotropin‐releasing hormone. Temporal expression profiling shows that both Rhopr‐ACP and Rhopr‐ACPR are upregulated after ecdysis, suggesting that this neuropeptide may be involved in processes associated with post‐ecdysis.

Transcriptomic characterization and curation of candidate neuropeptides regulating reproduction in the eyestalk ganglia of the Australian crayfish, Cherax quadricarinatus

“…ACP has been demonstrated to act as a neurohormone in the central nervous system of Rhodnius prolixus 88, however we only detected expression of Cq -ACP in the eyestalk of C. quadricarinatus . Temporal expression profiling shows that both Rhopr-ACP and Rhopr-ACPR are upregulated after ecdysis, and the author suggested that this neuropeptide may be involved in processes associated with post-ecdysis89. Still, little is known about the function of this neuropeptide.…”

Recent advances in neuropeptide signaling in Drosophila, from genes to physiology and behavior

“…RNAi mediated knockdown of the ACP receptor in T. castaneum has no effect on physical appearance, egg number and mortality. Both ACP and its receptor are predominantly expressed in the CNS of T. castaneum [195], R. prolixus [166] and A. aegypti [211], which indicates a neuromodulatory role for this signaling system. In addition, the temporal expression profile data suggest that ACP could be involved in post-ecdysis related processes [166,211].…”

“…ACP has a broader distribution in mosquitoes where ACP-like immunoreactivity was also detected in neurons in thoracic ganglia [221]. ACP may act as a central neuromodulator, since its receptor is predominantly found in the central nervous system [166,195]. The specific function of ACP signaling remains unknown, although its temporal expression suggests that it may play a role in development and/or ecdysis [166,195,211].…”

Description of a Brain Neuropeptidome of the Malaria Vector Nyssorhynchus Albimanus and Neuropeptide Differential Expression During Infection with Plasmodium Berghei

“…The structural and sequential analysis described this neuropeptide in several insects, including anophelines. ACP is primarily expressed in the nervous system and, to a lesser extent, in other insect organs and tissues [110,111]. ACP transcripts were detected in the head and thorax of larvae, pupae, and adult of Ae.…”