Development of a preliminary in vitro drug screening assay based on a newly established culturing system for pre-adult fifth-stage Onchocerca volvulus worms

Denis Voronin; Nancy Tricoche; Shabnam Jawahar; Michael Shlossman; Christina A Bulman; Chelsea Fischer; Michael T Suderman; Judy A Sakanari; Sara Lustigman

doi:10.1371/journal.pntd.0007108

Development of a preliminary in vitro drug screening assay based on a newly established culturing system for pre-adult fifth-stage Onchocerca volvulus worms

PLoS Negl Trop Dis. 2019 Jan 17;13(1):e0007108. doi: 10.1371/journal.pntd.0007108. eCollection 2019 Jan.

Authors

Denis Voronin¹, Nancy Tricoche¹, Shabnam Jawahar¹, Michael Shlossman¹, Christina A Bulman², Chelsea Fischer², Michael T Suderman³, Judy A Sakanari², Sara Lustigman¹

Affiliations

¹ Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America.
² Dept. of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America.
³ Cell Systems-3D, LLC, Kemah, Texas, United States of America.

Abstract

Background: The human filarial parasite Onchocerca volvulus is the causative agent of onchocerciasis (river blindness). It causes blindness in 270,000 individuals with an additional 6.5 million suffering from severe skin pathologies. Current international control programs focus on the reduction of microfilaridermia by annually administering ivermectin for more than 20 years with the ultimate goal of blocking of transmission. The adult worms of O. volvulus can live within nodules for over 15 years and actively release microfilariae for the majority of their lifespan. Therefore, protracted treatment courses of ivermectin are required to block transmission and eventually eliminate the disease. To shorten the time to elimination of this disease, drugs that successfully target macrofilariae (adult parasites) are needed. Unfortunately, there is no small animal model for the infection that could be used for discovery and screening of drugs against adult O. volvulus parasites. Here, we present an in vitro culturing system that supports the growth and development of O. volvulus young adult worms from the third-stage (L3) infective stage.

Methodology/principal findings: In this study we optimized the culturing system by testing several monolayer cell lines to support worm growth and development. We have shown that the optimized culturing system allows for the growth of the L3 worms to L5 and that the L5 mature into young adult worms. Moreover, these young O. volvulus worms were used in preliminary assays to test putative macrofilaricidal drugs and FDA-approved repurposed drugs.

Conclusion: The culture system we have established for O. volvulus young adult worms offers a promising new platform to advance drug discovery against the human filarial parasite, O. volvulus and thus supports the continuous pursuit for effective macrofilaricidal drugs. However, this in vitro culturing system will have to be further validated for reproducibility before it can be rolled out as a drug screen for decision making in macrofilaricide drug development programs.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Drug Evaluation, Preclinical / methods*
Female
Filaricides / pharmacology*
Male
Onchocerca volvulus / drug effects*
Onchocerca volvulus / growth & development*
Parasitic Sensitivity Tests / methods*

Substances

Filaricides

Grants and funding

This work was funded by the Bill & Melinda Gates Foundation (http://www.gatesfoundation.org/) grants # OPP1017584, OPP1099849, OPP1171883, and OPP1086618, and by the New York Blood Center intramural funding. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.