Trevisan, Paula et al. (2021) International Worm Meeting "Toxicological evaluation of curcumin nanocapsules in Caenorhabditis elegans"

Araujo Agarrayua, Danielle, Silva de Avila, Daiana, Trevisan, Paula, Porto Ineu, Rafael

[International Worm Meeting, 2021]

Curcumin is the main bioactive polyphenolic compound present in the turmeric rhizomes and has become the target of studies in several areas of knowledge due to the variety of its biological properties that it presents, as an antioxidant, anti-inflammatory and neuroprotective activity. Its low bioavailability, insolubility in water and its instability limit its application, hindering its action and absorption. Various techniques can be used to improve the dissolution and bioavailability of bioactives. Curcumin nanoencapsulation has been used to increase its bioavailability, being an excellent tool for controlled release and vectoring for tissues of interest. However, little is known about its safety. Recently, there is an increasing number of studies on nanotoxicology in Caenorhabditis elegans. C. elegans is an animal model with potential advantages for studies of nutraceutical activity such as relatively short life, easy maintenance, low cost, litter size and several mutant strains. In this context, our objective was to evaluate the interaction effects of curcumin nanoparticles encapsulated by the poly capr - caprolactone polymer (PCL) in C. elegans in order to obtain information about the potential for toxicity. The worms in the first larval stage (L1), were obtained by a process of synchronization. After 14 hours of the synchronization process, the newly hatched larvae were treated with different concentrations (10 muM, 30 muM and 100 muM) of nanoparticles containing curcumin, empty nanoparticles and free curcumin, for 30 minutes, in liquid medium. Soon after, all this medium containing the treatment was placed in Petri dishes containing NGM and E. coli for 48 h. After 48 h (chronic exposure), the worms were analyzed. For survival tests, they were counted and compared with the control group in order to draw a survival curve. Reproduction was assessed by the size of the litter. To determine the size of the animals, photos were taken with the aid of a microscope with a camera attached. All experiments were done in duplicate and repeated at least 3 times. Data were expressed as mean ± standard error, and were statistically analyzed using one-way ANOVA and Tukey's post-hoc. It can be seen that both nanoparticles with curcumin, white nanoparticles and free curcumin did not cause a significant difference in the survival rate of the worms compared to the control. In determining the size of the litter and the size of the worms, it was observed that only the free curcumin significantly decreased these parameters in the concentration of 30 muM in relation to the control. The formulation of PCL nanoparticles carrying curcumin can be considered safe, and these results indicate that C. elegans can be a good alternative in vivo for nanotoxicology studies providing accurate and fast results.

James Legg et al. (2006) European Worm Meeting "Testing the in vivo Importance of Putative Regulatory Sites in IP3 Receptors"

Rafael Vazquez-Manrique, Howard Baylis, James Legg

[European Worm Meeting, 2006]

James Legg, Rafael Vazquez-Manrique and Howard Baylis. Signalling through the second messenger inositol trisphosphate (IP3) and its receptor (IP3R) is a central mechanism by which extracellular signals regulate intracellular calcium signals. IP3 signalling plays roles in a wide range of processes in C. elegans. For example, IP3 signalling is widely involved in non-neuronal ultradian rhythmic processes; in particular feeding, defecation and ovulation (see 1 and references therein). IP3 signalling is also involved in developmental processes; embryos with disrupted IP3 signalling have defects in differentiation and in morphogenesis (2,3). The ability of IP3Rs to function in such a diverse range of processes is likely to require complex differential regulation. This is likely to be achieved, in part, through modulation of IP3R activity by other signalling molecules. A substantial number of potential and putative regulatory interactions have been identified in IP3Rs from a range of sources. These include interactions with other proteins and with small ligands such as ATP. Although much of this work has been performed with mammalian IP3Rs, the binding sites for many of these interactors are conserved in the C. elegans receptor. We have recently established a system that allows us to modify the itr-1 genomic DNA using homologous recombination in E. coli and then reintroduce modified itr-1 genes into C. elegans, in particular into itr-1 l.o.f mutants. This allows us to test the effects of modifying particular binding sites in the IP3R on its ability to rescue particular functions. We have used this system to test the importance of two sites (a) a putative ATP binding site and (b) the predicted binding site for FKBP12. Disruption of the ATP binding site appears to have modest effects on itr-1 function whereas disruption of the FKBP12 site appears to have severe effects on function. Therefore this system allows us to test the importance of regulatory sites, identified using biochemical and molecular approaches, in whole animals.. 1. Baylis HA (2005) Cell 123, 5-7. 2. Walker DS et al. (2002) Mol Biol Cell 13, 1329-1337. 3. Thomas-Virnig CL et al. (2004) Curr Biol 14,1882-1887