Venom Proteomics of Trimeresurus gracilis, a Taiwan-Endemic Pitviper, and Comparison of Its Venom Proteome and VEGF and CRISP Sequences with Those of the Most Related Species

Proteogenomic approaches for snake venom protein-based drug development: current trends and challenges

Snake venom proteins have long been recognized for their therapeutic potential. Proteogenomic strategies, integrating transcriptomics and proteomics, have emerged as powerful tools for identifying and characterizing venom proteins for the development of novel therapeutic agents. Analytical techniques like mass spectrometry and next-generation sequencing enable comprehensive analysis, identifying key venom components and their variants. Recent studies unveil the diversity and complexity of snake venom, highlighting species-specific variations in toxin composition. Structural biology techniques, including x-ray crystallography and cryo-electron microscopy, provide insights into venom enzyme structures and mechanisms of action, facilitating drug design. Bioinformatics tools aid in data analysis and prediction of venom protein functions, enhancing drug discovery efforts. Despite advancements, challenges persist, including toxicity, formulation stability and clinical validation. This review describes the current as well as future options for research and development and emphasizes the critical role of proteogenomic techniques in developing snake venom protein-based drugs.

Clinical manifestations of alpine pit viper (Trimeresurus gracilis) bites

INTRODUCTION

The alpine pit viper, Trimeresurus gracilis, is an endemic species in Taiwan. The incidence of human envenoming is rare.

CASE SUMMARIES

We present three events in two patients bitten by Trimeresurus gracilis. In the first patient, envenoming inflicted pain, local bleeding, hemorrhagic bulla, and progressive swelling, leading to necrosis of the bite wound. In the second patient, the two snakebites caused pain and progressive swelling. There were no systemic effects such as organ damage or neurological deficits observed. A paraspecific antivenom against Trimeresurus stejnegeri and Protobothrops mucrosquamatus was used to treat both patients, with a favorable outcome in each.

DISCUSSION

Combined with the clinical manifestations of two previously reported cases of Trimeresurus gracilis envenoming, the known effects of Trimeresurus gracilis venom in humans include local toxicities, severe soft-tissue damage, compartment syndrome, and coagulopathy without spontaneous systemic bleeding. The paraspecific antivenom, which has demonstrable cross-neutralization effects in animal studies, appeared to be effective against the local toxicities as the patients showed prompt cessation of the progression of their swelling.

CONCLUSIONS

The knowledge of clinical manifestations and management approaches to Trimeresurus gracilis envenoming is helpful for patient care. The use of the paraspecific antivenom should be considered in managing such envenoming.

In vitro immunoreactivity and in vivo neutralization of Trimeresurus gracilis venom with antivenoms targeting four pit viper species

Snakebite envenomation is a significant global health issue that requires specific antivenom treatments. In Taiwan, available antivenoms target a variety of snakes, but none specifically target Trimeresurus gracilis, an endemic and protected species found in the high mountain areas of Taiwan. This study evaluated the effectiveness of existing antivenoms against T. gracilis venom, focusing on a bivalent antivenom developed for Trimeresurus stejnegeri and Protobothrops mucrosquamatus (TsPmAV), as well as monovalent antivenoms for Deinagkistrodon acutus (DaAV) and Gloydius brevicaudus (GbAV). Our research involved in vivo toxicity testing in mice and in vitro immunobinding experiments using (chaotropic) enzyme-linked immunosorbent assays, comparing venoms from four pit viper species (T. gracilis, T. stejnegeri, P. mucrosquamatus, and D. acutus) with three types of antivenoms. These findings indicate that TsPmAV partially neutralized T. gracilis venom, marginally surpassing the efficacy of DaAV. In vitro tests revealed that GbAV displayed higher binding capacities toward T. gracilis venom than TsPmAV or DaAV. Comparisons of electrophoretic profiles also reveal that T. gracilis venom has fewer snake venom C-type lectin like proteins than D. acutus, and has more P-I snake venom metalloproteases or fewer phospholipase A2 than G. brevicaudus, T. stejnegeri, or P. mucrosquamatus. This study highlights the need for antivenoms that specifically target T. gracilis, as current treatments using TsPmAV show limited effectiveness in neutralizing local effects in patients. These findings provide crucial insights into clinical treatment protocols and contribute to the understanding of the evolutionary adaptation of snake venom, aiding in the development of more effective antivenoms for human health.

Comparisons of the Oral Microbiota from Seven Species of Wild Venomous Snakes in Taiwan Using the High-Throughput Amplicon Sequencing of the Full-Length 16S rRNA Gene

A venomous snake's oral cavity may harbor pathogenic microorganisms that cause secondary infection at the wound site after being bitten. We collected oral samples from 37 individuals belonging to seven species of wild venomous snakes in Taiwan, including Naja atra (Na), Bungarus multicinctus (Bm), Protobothrops mucrosquamatus (Pm), Trimeresurus stejnegeri (Ts), Daboia siamensis (Ds), Deinagkistrodon acutus (Da), and alpine Trimeresurus gracilis (Tg). Bacterial species were identified using full-length 16S rRNA amplicon sequencing analysis, and this is the first study using this technique to investigate the oral microbiota of multiple Taiwanese snake species. Up to 1064 bacterial species were identified from the snake's oral cavities, with 24 pathogenic and 24 non-pathogenic species among the most abundant ones. The most abundant oral bacterial species detected in our study were different from those found in previous studies, which varied by snake species, collection sites, sampling tissues, culture dependence, and analysis methods. Multivariate analysis revealed that the oral bacterial species compositions in Na, Bm, and Pm each were significantly different from the other species, whereas those among Ts, Ds, Da, and Tg showed fewer differences. Herein, we reveal the microbial diversity in multiple species of wild snakes and provide potential therapeutic implications regarding empiric antibiotic selection for wildlife medicine and snakebite management.