Aphidius ervi Teratocytes Release Enolase and Fatty Acid Binding Protein Through Exosomal Vesicles

Abstract

The molecular bases of the host-parasitoid interactions in the biological system Acyrthosiphon pisum (Harris) (Homoptera, Aphididae) and Aphidius ervi (Haliday) (Hymenoptera, Braconidae) have been elucidated allowing the identification of a gamma-glutamyl transpeptidase, the active component of maternal venom secretion, and teratocytes, the embryonic parasitic factors responsible for host physiology regulation after parasitization. Teratocytes, cells deriving from the dissociation of the serosa, the parasitoid embryonic membrane, are responsible for extra-oral digestion of host tissues in order to provide a suitable nutritional environment for the development of parasitoid larvae. Teratocytes rapidly grow in size without undergoing any cell division, synthesize, and release in the host hemolymph two proteins: a fatty acid binding protein ( Ae- FABP) and an enolase ( Ae -ENO). Ae- FABP is involved in transport of fatty acids deriving from host tissues to the parasitoid larva. Ae -ENO is an extracellular glycolytic enzyme that functions as a plasminogen like receptor inducing its activation to plasmin. Both Ae -FABP and Ae -ENO lack their signal peptides, and they are released in the extracellular environment through an unknown secretion pathway. Here, we investigated the unconventional mechanism by which teratocytes release Ae -FABP and Ae-ENO in the extracellular space. Our results, obtained using immunogold staining coupled with TEM and western blot analyses, show that these two proteins are localized in vesicles released by teratocytes. The specific dimension of these vesicles and the immunodetection of ALIX and HSP70, two exosome markers, strongly support the hypothesis that these vesicles are exosomes.

Identification and Functional Characterization of Toxoneuron nigriceps Ovarian Proteins Involved in the Early Suppression of Host Immune Response

“…These alterations of the physiology and development of the host are essential for the survival of the offspring of the parasitoid [34]. The role of the teratocytes have been studied only in a restricted number of Braconidae and these studies have demonstrated that they can produce and often secrete a set of proteins with different characteristics and functions [35]. It is hypothesized that the factors secreted from this type of cells include inhibitors of the immune response, fungicide molecules, inhibitors of the juvenile hormone, protease, inhibitors of the phenoloxidase, molecules that block the production of ecdysteroids, and other factors that contribute to the nourishment of the parasitoid [35].…”

“…The role of the teratocytes have been studied only in a restricted number of Braconidae and these studies have demonstrated that they can produce and often secrete a set of proteins with different characteristics and functions [35]. It is hypothesized that the factors secreted from this type of cells include inhibitors of the immune response, fungicide molecules, inhibitors of the juvenile hormone, protease, inhibitors of the phenoloxidase, molecules that block the production of ecdysteroids, and other factors that contribute to the nourishment of the parasitoid [35]. Thus, teratocytes are involved in the regulation of the host to obtain nutrients from its tissues and then to provide them to the parasitoid larva for its development [36].…”

Structural and Functional Characterization of a Novel Recombinant Antimicrobial Peptide from Hermetia illucens

“…For their high biodiversity, with over one million described species, insects represent the largest class of organisms, with a high ability to adapt to environmental changes and high resistance to a broad spectrum of pathogens [9,10]. Insects, lacking an adaptive immune system, base their defense/survival on the production of a multitude of broadspectrum AMPs [11]; therefore, these organisms represent an essential source of biologically active compounds [12][13][14]. In particular, the dipteran Hermetia illucens, is considered an excellent model system for the identification and characterization of new AMPs since it is able to live in hostile environments rich in pathogens.…”

A teratocyte‐specific serpin from the endoparasitoid wasp Cotesia vestalis inhibits the prophenoloxidase‐activating system of its host Plutella xylostella

“…Three parasitic factors, including polydnavirus (PDVs), venom and teratocytes, have been adopted by wasps to impede the host immunity (Beckage & Gelman, 2004;Laurino et al, 2016;Salvia et al, 2017Salvia et al, , 2018Salvia et al, , 2019. Moreover, there is a further parasitic factor that must be taken into account, ovarian proteins (Salvia et al, 2021).…”