Venom is a complex cocktail of biomolecules that is secreted in a specialised gland or cell of a venomous animal. It is actively delivered to the target animal to facilitate prey-capture or anti-predator self-defence. Venom has underpinned the evolutionary success of numerous animal lineages and has independently originated over 100 times. In our lab, we investigate venomous animals and their venoms as model systems to address broad and interesting questions in genetics, ecology and evolution. Some of the major lines of research in the lab are briefly described below.
Annually, over 58,000 deaths occur in India due to snakebites. In addition, four times this number suffer from permanent loss-of-function injuries, such as amputations of digits and limbs. A large majority of snakebite victims are farmers and labourers in rural regions, who are also the primary breadwinners of their families. Snakebites, therefore, devastate entire families and has a tremendous negative impact on our economy.
Snakebites are treated using antivenoms, which are produced by immunising equines with snake venoms and sourcing the resultant anti-toxin antibodies. Our research has demonstrated that snake venoms vary dramatically in both composition and potency between species (Senji et al. 2019, 2021a, 2021b; Attarde et al. 2021), within different populations of the same snake species (Sunagar et al. 2014), and between different individuals of the same population, even within a smaller geographic area (Rashmi et al. 2021).
Ignoring this geographic variation in venom, Indian antivenoms are still manufactured using the venoms of a single population of snakes in the southern part of the country (a couple of districts in Tamil Nadu). Our research has demonstrated that these antivenoms fail to counter the remarkable variation in venoms of Indian snakes (Senji et al. 2019, 2021a, 2021b; Kaur et al. 2020; Attarde et al. 2021). Moreover, Indian antivenoms are only manufactured against the so-called ‘big four’ snakes. Specific antivenom products against many other medically important snakes that are capable of causing mortality and morbidity do not exist. Our findings highlight that India needs efficient snakebite therapy to save lives, limbs and livelihoods of hundreds of thousands of Indians annually.
Senji Laxme RR, Khochare S, DeSouza HF, Ahuja B, Suranse V, Martin G, Whitaker R and Sunagar K. 2019. Beyond the ‘big four’: Venom profiling of the medically important yet neglected Indian snakes reveals disturbing antivenom deficiencies. PLOS Neglected Tropical Diseases.
Senji Laxme RR, Attarde S, Khochare S, Suranse V, Martin G, Casewell NRC, Whitaker R, and Sunagar K. 2021. Biogeographical venom variation in the Indian spectacled cobra (Naja naja) underscores the pressing need for pan-India efficacious snakebite therapy. PLOS Neglected Tropical Diseases.
Senji Laxme RR, Attarde S, Khochare S, Suranse V, Iyer A, Martin G, Casewell NRC, Whitaker R, and Sunagar K. 2021. Biogeographic venom variation in Russell’s viper (Daboia russelii) and the preclinical inefficacy of antivenom therapy in snakebite hotspots. PLOS Neglected Tropical Diseases.
Rashmi U, Khochare S, Attarde S, Senji Laxme RR, Suranse V, Martin G and Sunagar K. 2021. Remarkable intrapopulation venom variability in the monocellate cobra (Naja kaouthia) unveils neglected aspects of India's snakebite problem. Journal of Proteomics.
Attarde S, Khochare S, Iyer A, Dam P, Martin G and Sunagar K. Venomics of the enigmatic Andaman cobra (N. sagittifera) and the preclinical failure of Indian antivenoms in Andaman and Nicobar Islands. Frontiers in Pharmacology.
Enhancing the efficacy of conventional antivenoms
The antivenom manufacturing strategy has remained virtually unchanged for over a century (Kaur et al. 2020). The Evolutionary Venomics Lab is collaborating with numerous conventional Indian antivenom manufacturers, including the Serum Institute of India, Premium Serums, VINS Biopharma, and Bharat Serums. In collaboration with these manufacturers, we are striving to improve the existing antivenom manufacturing strategies and immediately enhance the effectiveness of Indian antivenoms.
Attarde S, Iyer A, Khochare S, Shaligram U, Vikharankar M and Sunagar K. The preclinical evaluation of a second-generation antivenom for treating snake envenoming in India. Toxins. 2022.
Kaur N, Iyer A, and Sunagar K. 2021. Evolution bites: Timeworn inefficacious snakebite therapy in the era of recombinant vaccines. Indian Pediatrics. (58).
Discovery and expression of recombinant antivenoms
With funding from numerous national and international agencies, and in collaboration with the International AIDS Vaccine Initiative (USA), Liverpool School of Tropical Medicine (UK) and other partners, we are working towards the discovery and recombinant expression of broadly neutralising antibodies. These recombinant antibodies would be fished from animals (e.g., rabbits, camels, cows, baboons and horses) that are immunised with snake venoms in India and sub-Saharan Africa. Advanced technologies in B cell sorting, venom toxin synthesis, and antibody engineering will drive these projects.
Casewell NRC, Jackson TMW, Laustsen A, and Sunagar K. 2020. Causes and consequences of medically-important snake venom variation. Trends in Pharmacological Sciences.
Evolutionary ecology of venoms
The evolution of venom is tightly linked to the ecology and environment of the venomous animal. Unfortunately, our understanding of the influence of these factors on the venom of animals in the Indian subcontinent remains completely uninvestigated. To address this knowledge gap, we have been assessing the impact of various factors in shaping the composition, biochemical activity, potency, and evolution of venom in snakes, spiders, scorpions, centipedes and many other enigmatic lineages.
Sunagar K, Khochare S, Senji Laxme RR, Attarde S, Dam P, Suranse V, Khaire A, Martin G, and Captain A. 2021. A wolf in another wolf’s clothing: Post-genomic regulation dictates venom profiles of medically-important cryptic kraits in India. Toxins.
Suranse V, Iyer A, Jackson TNW and Sunagar K@. 2021. Origin and Early Diversification of the Enigmatic Squamate Venom Cocktail. A Contribution to the Origin and Early Evolution of Snakes (D. Gower and H. Zaher Ed.). Systematics Association Special Volume Series. Cambridge University Press (in Press).
Population genetics, phylogenetics and phylogeography of venomous animals
India is a land of diverse topographies and harbours vast biodiversity including many species of venomous organisms. However, these species clusters have not been critically evaluated within a molecular phylogenetic framework. An exhaustive investigation of these groups could potentially reveal new species unknown to science. Phylogenetic and phylogeographic investigations could provide interesting insights into the evolutionary relationships and the observed distribution patterns for these diverse groups. Furthermore, there is a paucity of the literature studying the population structures emerging as a consequence of local adaptations and the genetic makeup of venomous organisms. The lab employs population genetics tools to assess the integrity and viability of the natural populations of these organisms across their distribution and understand the underlying process shaping these population structures. These investigations could also have a bearing on the conservation efforts to safeguard these organisms and facilitate the framing of ecologically and evolutionarily guided policies.
Molecular evolution of venom
Identifying the evolutionary origin of venom and the molecular mechanisms that underpin its diversification are among the major interests of the lab. By utilising experimental and bioinformatic approaches, including genomics and evolutionary analyses, we aim to unravel the principles that facilitate the weaponization of non-toxic, physiological proteins into some of the most potent toxins in the world.
Suranse V, Jackson T. N. W. and Sunagar K. Contextual constraints: dynamic evolution of snake venom phospholipase A2. Toxins (in Press).
Sunagar K and Moran Y. The Rise and Fall of an Evolutionary Innovation: Contrasting Strategies of Venom Evolution in Ancient and Young Animals. 2015. PLoS Genetics. 11(10): e1005596.
Herzig V*, Sunagar K*, Wilson DR, Pineda SS, Israel MR, Duterte S, McFarland BS, Undheim EAB, Hodgson WC, Alewood PF, Lewis RJ, Bosmans F, Vetter I, King GF and Fry BG. 2020. Australian funnel-web spiders evolved human-lethal δ-hexatoxins for defense against vertebrate predators. Proceedings of the National Academy of Sciences.
Sunagar K, Jackson TNW, Undheim EAB, Ali S, Antunes A and Fry BG. 2013. Three-fingered RAVERs: Rapid Accumulation of Variations in Exposed Residues of snake venom toxins. Toxins. 5:2172-2208.