Biology subjects

Piermarini, P. M.

Publications and source records attributed to Piermarini, P. M..

4 recordsLinked to original sources

bioRxiv2025

Agonism of mosquito and human transient receptor potential ankyrin 1 (TRPA1) channels by the natural drimane sesquiterpene cinnamodial

TRPA1 channels are multi-modal receptors in animals for sensing noxious physical and chemical factors. They are considered promising biochemical targets for developing repellents of arthropod disease vectors and drugs to treat a variety of medical conditions including pain, inflammation, and itch. Recently, we discovered that cinnamodial (CDIAL), a natural drimane sesquiterpene produced by the medicinal plant Cinnamosma fragrans, agonizes mosquito TRPA1 channels and is antifeedant and repellent to Aedes aegypti. However, the selectivity of CDIAL for mosquito vs. human TRPA1 and how CDIAL binds to TRPA1 channels are unknown. Here we characterize the agonism by CDIAL of Aedes aegypti (Aa) and Homo sapiens (Hs) TRPA1 channels and compare it to that induced by two other known TRPA1 agonists, nepetalactone and JT010. Heterologous expression of AaTRPA1 and HsTRPA1 in Xenopus laevis oocytes revealed that CDIAL agonized both channels with similar potency. Nepetalactone was less potent of an agonist than CDIAL for both AaTRPA1 and HsTRPA1, but was a more specific agonist for AaTRPA1 over HsTRPA1 compared to CDIAL. JT010 did not detectably activate AaTRPA1, but was a more potent agonist of HsTRPA1 than CDIAL. To generate insights into a putative binding site of CDIAL on AaTRPA1 we mutated six Lys residues (656, 678, 681, 728, 738, 744) and/or a Cys residue (684) in the coupling domain previously hypothesized to be involved. Simultaneous mutation of the six Lys residues to Ala dampened agonistic responses of AaTRPA1 to CDIAL, whereas changing Cys684 to Ser had no detectable impact. Protein modeling and molecular docking simulations for both AaTRPA1 and HsTRPA1 suggest species-specific CDIAL-binding mechanisms to the coupling domain, which involve Lys681 in AaTRPA1 and Cys621 in HsTRPA1.

pharmacology and toxicology↗

bioRxiv2023

Dietary calcium (Ca2+) impacts Ca2+ content and molecular expression of Ca2+-transporters in Malpighian tubules of the yellow fever mosquito, Aedes aegypti

The renal (Malpighian) tubules of insects play important roles in hemolymph Ca2+ regulation. Here we provide the first investigation into how dietary Ca2+ loads from sucrose or blood meals affect the Ca2+ content and mRNA expression of Ca2+ transporters in Malpighian tubules of adult female mosquitoes. Using the yellow fever mosquito Aedes aegypti we found that feeding females for 6 days ad libitum on 10% sucrose with elevated Ca2+ concentration led to concentration-dependent increases of the Ca2+ content in Malpighian tubules. The increases of Ca2+ content correlated with up-regulations of mRNAs encoding intracellular Ca2+-ATPases (SERCA and SPCA), a plasma membrane Ca2+ -ATPase (PMCA), and a K+-dependent Na+/Ca2+ exchanger (NCKX1). We also found that when adult females were fed blood, tubule Ca2+ content changed dynamically over the next 72 h in a manner consistent with redistribution of tubule Ca2+ stores to other tissues (e.g., ovaries). The changes in tubule Ca2+ were correlated with dynamic changes in mRNA abundances of SERCA, SPCA, PMCA, and NCKX1. Our results are the first to demonstrate that Malpighian tubules of adult female mosquitoes have a remarkable capacity to handle high dietary Ca2+ loads, most likely through the combination of storing excess Ca2+ within intracellular compartments and secreting it into the tubule lumen for excretion. Our results also suggest that the Malpighian tubules play key roles in supplying Ca2+ to other tissues during the processing of blood meals.

physiology↗

bioRxiv2020

Stop the crop: insights into the insecticidal mode of action of cinnamodial against mosquitoes

Cinnamodial (CDIAL) is a drimane sesquiterpene dialdehyde found in the bark of Malagasy medicinal plants (Cinnamosma species; family Canellaceae). We previously demonstrated that CDIAL was insecticidal, antifeedant, and repellent against Aedes aegypti mosquitoes. The goal of the present study was to generate insights into the insecticidal mode of action for CDIAL, which is presently unknown. We evaluated the effects of CDIAL in vitro on the contractility of the ventral diverticulum (crop) in adult female Ae. aegypti. The crop is a food storage organ surrounded by visceral muscle that spontaneously contracts in vitro. We found that CDIAL completely inhibited spontaneous contractions of the crop as well as those stimulated by the agonist 5-hydroxytryptamine. Several derivatives of CDIAL with known insecticidal activity also inhibited crop contractions. Morphometric analyses of crops suggested that CDIAL induced a tetanic paralysis that was dependent on extracellular Ca2+ and inhibited by Gd3+, a non-specific blocker of plasma membrane Ca2+ channels. Screening of numerous pharmacological agents revealed that a Ca2+ ionophore (A23187) was the only compound other than CDIAL to completely inhibit crop contractions via a tetanic paralysis. Taken together, our results suggest that CDIAL inhibits crop contractility by elevating intracellular Ca2+ through the activation of plasma membrane Ca2+ channels thereby leading to a tetanic paralysis, which may explain the insecticidal effects of CDIAL against mosquitoes. Our pharmacological screening efforts also revealed the presence of two regulatory pathways in mosquito crop contractility not previously described: an inhibitory glutamatergic pathway and a stimulatory octopaminergic pathway. The latter was also completely inhibited by CDIAL.

physiology↗

bioRxiv2017

Analysis of the Aedes albopictus C6/36 genome provides insight into cell line adaptations to in vitro viral propagation

BackgroundThe 50-year old Aedes albopictus C6/36 cell line is a resource for the detection, amplification, and analysis of mosquito-borne viruses including Zika, dengue, and chikungunya. The cell line is derived from an unknown number of larvae from an unspecified strain of Aedes albopictus mosquitoes. Toward improved utility of the cell line for research in virus transmission, we present an annotated assembly of the C6/36 genome.\n\nResultsThe C6/36 genome assembly has the largest contig N50 (3.3 Mbp) of any mosquito assembly, presents the sequences of both haplotypes for most of the diploid genome, reveals independent null mutations in both alleles of the Dicer locus, and indicates a male-specific genome. Gene annotation was computed with publicly available mosquito transcript sequences. Gene expression data from cell line RNA sequence identified enrichment of growth-related pathways and conspicuous deficiency in aquaporins and inward rectifier K+ channels. As a test of utility, RNA sequence data from Zika-infected cells was mapped to the C6/36 genome and transcriptome assemblies. Host subtraction reduced the data set by 89%, enabling faster characterization of non-host reads.\n\nConclusionsThe C6/36 genome sequence and annotation should enable additional uses of the cell line to study arbovirus vector interactions and interventions aimed at restricting the spread of human disease.

genomics↗