Tricoche, N. | Search bioRxiv

bioRxiv2023

Discovery of New Broad-Spectrum Anti-Infectives for Eukaryotic Pathogens Using Bioorganometallic Chemistry

Drug resistance observed with many anti-infectives clearly highlights the need for new broad-spectrum agents to treat especially neglected tropical diseases (NTDs) caused by eukaryotic parasitic pathogens including fungal infections. Since these diseases target the most vulnerable communities who are disadvantaged by health and socio-economic factors, new agents should be, if possible, easy-to-prepare to allow for commercialization based on their low cost. In this study, we show that simple modification of one of the most well-known antifungal drugs, fluconazole, with organometallic moieties not only improves the activity of the parent drug but also broadens the scope of application of the new derivatives. These compounds were highly effective in vivo against pathogenic fungal infections and potent against parasitic worms such as Brugia, which causes lymphatic filariasis and Trichuris, one of the soil-transmitted helminths that infects millions of people globally. Notably, the identified molecular targets indicate a mechanism of action that differs greatly from the parental antifungal drug, including targets involved in biosynthetic pathways that are absent in humans, offering great potential to expand our armamentarium against drug-resistant fungal infections and NTDs targeted for elimination by 2030. Overall, the discovery of these new compounds with broad-spectrum activity opens new avenues for the development of treatments for several current human infections, either caused by fungi or by parasites, including other NTDs, as well as newly emerging diseases. ONE-SENTENCE SUMMARYSimple derivatives of the well-known antifungal drug fluconazole were found to be highly effective in vivo against fungal infections, and also potent against the parasitic nematode Brugia, which causes lymphatic filariasis and against Trichuris, one of the soil-transmitted helminths that infects millions of people globally.

pharmacology and toxicology↗

bioRxiv2020

Optimizing 3-dimensional human skin models to facilitate long-term development of Onchocerca volvulus, a debilitating obligatory human parasite

Onchocerciasis also known as river blindness is a neglected tropical disease and the world’s second-leading infectious cause of blindness in humans; it is caused by Onchocerca volvulus. Current therapies kill microfilariae but fail to kill the adult parasites, which reside within subcutaneous nodules. To support a more target-driven drug development that can also cure and thus support the elimination of this disease, an in-depth understanding of O. volvulus biology especially the factors that support the longevity of these worms in the human host (>10 years) is required. However, research is hampered by a lack of access to adult worms. O. volvulus is an obligatory human parasite and no small animal models that can propagate this parasite were successfully developed. The current optimized 2-dimensional (2-D) in vitro culturing method starting with O. volvulus infective larvae does not yet support the development of mature adult worms. To overcome these limitations, we have developed 3-dimensional (3-D) culture systems that simulated the human in vivo niche using in vitro engineered skin and adipose tissue. We show that an optimized indirect co-culture of in vitro skin tissue with fourth-stage larvae supported a significant increase in growth until the pre-adult stage with a median length of 816 – 831 μm as compared to 767 μm of 2-D cultured larvae. Notably, when larvae were co-cultured directly with adipose tissue models, a significant improvement for larval motility and thus fitness was observed; 95 % compared to 26 % in the 2-D system. These promising co-culture concepts are a first step to further improve the long-term development of adult worms in vitro, and thus provide the filarial research community with a valuable source of O. volvulus worms at various developmental stages, which may accelerate innovative unsolved biomedical inquiries into the parasite’s biology.Author summary The filarial nematode Onchocerca volvulus is an obligatory human parasite and the causative agent of onchocerciasis, better known as river blindness. In 2017, more than 20 million infections with O. volvulus were estimated worldwide, 99 % of the patients live in Africa. Current international control programs focus on the reduction of microfilaridermia by mass drug administration of ivermectin. However, to meet the elimination goals, additional therapy strategies are needed that also target the adult worms. As this parasite is obliged to humans, there are no small animal models that sustain the full life cycle of the parasite, thus greatly impeding the research on this filarial nematode. To overcome these drawbacks, we developed co-culture systems based on engineered human skin and adipose tissue that represent the in vivo niche of O. volvulus in which we were able to establish improved conditions of culturing to the pre-adult stages of the parasite. Furthermore, our new culture approach could significantly reduce the use of animal models currently used for drug testing of surrogate larvae.View Full Text

bioengineering↗