Cyclotides are a highly stable family of cyclic peptides found in different plants [1]. Interest in these compounds began with the identification of Kalata B1, the uterotonic compound from Oldenlandia affinis [2], and it has resulted in the discovery of hundreds of cyclotides sequences, both natural and synthetic, and the exploration of their biological activities [3] and the host-defense role they play in plants. [4] A previous study by A. Bajpai et al. shows effects of cyclotides on the morphology and behavior of Caenorhabditis elegans [5], resulting in a dose dependent decrease of motile worms after exposure, and the formation of blebs and unusual structures in the worms. Because of the convenience of C. elegans as a biological model and their high genetic homology to humans [6], we aim to find cellular targets by following worms’ proteomic changes after exposure to cyclotides.
We extracted cyclotides from different Bolivian plants from Violaceae and Rubiaceae families. After de novo sequencing via MS/MS cyclotides were prepared in concentrations ranging from 1 to 100 ug/ml to be exposed to the worms along with ivermectin as positive control. The L1 stage synchronized worms exposed to the compounds and controls were followed up 2 and 3 days after exposure for morphological changes, egg laying ability, motility and development speed. Worms were kept at -80°C to stop development and preserve material until proteomic analysis.
Worms exposed to cyclotide high concentrations showed reduced developmental speed and egg laying capacities, assessed by quantifying the distance moved over time and automated egg counting. Some also exhibited early signs of senescence such as vulval protrusion. Some cyclotides caused the worms to move significantly less during development, likely impacting feeding and growth. All exposed worms will now undergo proteomic analysis to correlate the behavioral and morphological changes with affected cellular pathways.