Unraveling the distinctive venomous features of the saturniid Hylesia sp.: An integrative approach of a public health concern in Argentina

Exploring oak processionary caterpillar induced lepidopterism (Part 1): unveiling molecular insights through transcriptomics and proteomics

Lepidopterism, a skin inflammation condition caused by direct or airborne exposure to irritating hairs (setae) from processionary caterpillars, is becoming a significant public health concern. Recent outbreaks of the oak processionary caterpillar (Thaumetopoea processionea) have caused noteworthy health and economic consequences, with a rising frequency expected in the future, exacerbated by global warming promoting the survival of the caterpillar. Current medical treatments focus on symptom relief due to the lack of an effective therapy. While the source is known, understanding the precise causes of symptoms remain incomplete understood. In this study, we employed an advanced method to extract venom from the setae and identify the venom components through high-quality de novo transcriptomics, venom proteomics, and bioinformatic analysis. A total of 171 venom components were identified, including allergens, odorant binding proteins, small peptides, enzymes, enzyme inhibitors, and chitin biosynthesis products, potentially responsible for inflammatory and allergic reactions. This work presents the first comprehensive proteotranscriptomic database of T. processionea, contributing to understanding the complexity of lepidopterism. Furthermore, these findings hold promise for advancing therapeutic approaches to mitigate the global health impact of T. processionea and related caterpillars.

1H NMR Profiling of the Venom from Hylesia continua: Implications of Small Molecules for Lepidopterism

Lepidopterism caused by caterpillar contact is considered a public health problem around the world. The local and systemic responses of this pathology include short- and long-term inflammatory events. Although the proteolytic activity of the venoms from caterpillars is strongly associated with an inflammatory response in humans and murine models, fast and acute symptoms such as a burning sensation, itching, and pain should be related to the presence of low-weight hydrophilic molecules which easily influence cell metabolism. This investigation reports on the ¹H-Nuclear Magnetic Resonance (NMR) profiling of the venom from the larva of Hylesia continua, a caterpillar linked to frequent cases of lepidopterism in the northern highlands of Puebla, Mexico. According to one-dimensional (1D) and two-dimensional (2D) NMR data, the venom of H. continua contained 19 compounds with proven pain-inducing activity (i.e., acetic acid, lactic acid, formic acid, succinic acid, 2-hydroxyglutaric acid, ethanol, and glutamate), inflammatory activity (i.e., cadaverine, putrescine, and acetoin), as well as natural immunosuppressive activity (i.e., O-phosphocholine and urocanic acid). The levels of the 19 compounds were calculated using quantitative-NMR (qNMR) and extensively discussed on the basis of their toxic properties which partially explain typical symptoms of lepidopterism caused by the larvae of H. continua. To the best of our knowledge, this is the first investigation reporting a complex mixture of small molecules with inflammatory properties dissolved in the venom of a lepidopteran larva.

Unraveling the venom chemistry with evidence for histamine as key regulator in the envenomation by caterpillar Automeris zaruma

Over the past decades, envenomation by caterpillars of Automeris spp. became an increasing health problem in Latin America. Accidental contact with the stinging spines of these caterpillars cause acute local pain, itching, inflammation and skin rashes that persists for days. Even when the cause is obvious, the exact molecular mechanisms responsible for the observed symptoms are yet to be elucidated. Here, we describe for the first time, an active compound in the venom and the study of the bioactivity of the venom extracted from the spines of the caterpillar Automeris zaruma. Electrophysiological screening of a library of membrane proteins important for pain and itch enabled us to investigate and reveal the mode of action of the venom of A. zaruma. Further mass spectrometric analysis (Q-TOF-MS) made it possible to establish a link between the bioactivity and the components found in the venom. We show that the spine extract of A. zaruma contains histamine that potently activates the four types of the human histamine receptors (H1R, H2R, H3R and H4R) with a selectivity preference towards H3R and H4R. Furthermore, a modulation of the target MRGPRX2 was found. Together, these findings are the first to explain the symptomology of A. zaruma envenomation, enabling us a better understanding of caterpillar envenomation and predict that the hurdle of the scarce efficacy of the currently used antihistaminic drugs can be overcome by including H3R and H4R blockers in the clinical used medication. Such an approach might be used for other caterpillar envenomation in the world and represent a significant improvement for the well-being of the patient.