The Latoia consocia Caterpillar Induces Pain by Targeting Nociceptive Ion Channel TRPV1

Abstract

Accidental contact with caterpillar bristles causes local symptoms such as severe pain, intense heat, edema, erythema, and pruritus. However, there is little functional evidence to indicate a potential mechanism. In this study, we analyzed the biological characteristics of the crude venom from the larval stage of Latoia consocia living in South-West China. Intraplantar injection of the venom into the hind paws of mice induced severe acute pain behaviors in wild type (WT) mice; the responses were much reduced in TRPV1-deficit (TRPV1 KO) mice. The TRPV1-specific inhibitor, capsazepine, significantly attenuated the pain behaviors. Furthermore, the crude venom evoked strong calcium signals in the dorsal root ganglion (DRG) neurons of WT mice but not those of TRPV1 KO mice. Among the pain-related ion channels we tested, the crude venom only activated the TRPV1 channel. To better understand the venom components, we analyzed the transcriptome of the L. consocia sebaceous gland region. Our study suggests that TRPV1 serves as a primary nociceptor in caterpillar-induced pain and forms the foundation for elucidating the pain-producing mechanism.

Caterpillar Venom: A Health Hazard of the 21st Century

“…Different from other venomous insects, the larvae of a caterpillar lack a specialized venom gland [45]. Instead, venom is synthesized by secretory epithelial cells and stored inside the hollow canal of the setae [43]. The harpoon-shaped setae/spines have chitin-rich tips that easily break and thus serve as an injection needle for the venom.…”

“…It seems that not only the KKS mechanism may be involved. Both genetic and electrophysiological studies with whole-cell patch clamp have, in fact, shown that transient receptor potential vanilloid 1 channel (TRPV1) is one of the primary targets of the L. consocia venom ( Figure 5) [43].…”

“…By targeting the sensory nerve endings of the TRPV1 channel, it mediates nociceptive triggers from the peripheral nervous system to the central nervous system where it is received as pain. Additionally, Yao et al (2019) [43] did not rule out that more pain-related receptors are involved in the pathway. In their in vivo experiments, they saw that the paw licking behavior of the mice was not completely eliminated by a specific TRPV1 antagonist, capsazepine ( Figure 6).…”

“…For example, the DkTx toxin of the Chinese bird spider, Ornithoctonus huwena, activates TRPV1 channels and causes severe pain [76]. Also, the Chinese red-headed centipede (Scolopendra subspinipes) and some scorpion venoms induce pain by the same pathway [43].…”

Bv8-Like Toxin from the Frog Venom of Amolops jingdongensis Promotes Wound Healing via the Interleukin-1 Signaling Pathway

“…The fractions with contractile activity were pooled and further purified by a C 8 RP-HPLC (XBridge TM , C8, 5 µm, 25 × 0.46 cm, Waters, Milford, MA, USA). Elution was performed under solution A (water, 0.1% trifluoroacetic acid, v/v) and solution B (acetonitrile, 0.1% trifluoroacetic acid, v/v) with a linear solution B gradient of 0-100% as described previously [29]. During the elution, the absorbance value of the eluate was monitored at 215 nm/280 nm.…”