Soil-transmitted helminths (STHs) are common nematode parasites of the human intestinal tract. The main STHs are Ascaris, hookworms, and whipworms. These parasites infect >400,000,000 children worldwide, leading to significant malnutrition, physical stunting, cognitive deficiencies, school absenteeism, lower future earnings, lower educational status, vaccine failure, and immune deficiencies. The parasites also complicate pregnancies, cause lethargy, and result in low worker productivity in adults. Recent estimates have placed the burden of STH disease comparable of that malaria and cancer. In all these ways, the devastating impact of STH infections affect childhood health and development, maternal and adult health, and economic productivity in such a way as to trap endemic communities in a cycle of poverty, underdevelopment, and disease. Currently only one drug, albendazole, has adequate efficacy for single-dose mass drug administration. Albendazole has moderate and highly variable efficacy against hookworms and very poor efficacy against whipworms. Recent data have revealed instances of unusually low or reduced efficacy of albendazole over time against hookworms and Ascaris. New and improved classes of anthelmintics to treat STHs are urgently needed. This project proposes a radical new approach for deworming-use of the vertebrate-safe Bacillus thuringiensis crystal (Cry) protein, Cry5B (and potentially Cry14A), delivered via potent and unique formulations or via an engineered probiotic bacterium, Bacillus subtilis natto. Cry proteins are generally regarded as safe to humans. When given orally, single-dose Cry5B can cure hookworm infections in hamsters and Ascaris infections in pigs;whipworms are sensitive to Cry5B in vitro. Cry5B efficacy can be boosted using biological encapsulations. Probiotic Bacillus subtilis natto, eaten for centuries by the Japanese, can be engineered to express bioactive Cry5B with strong anthelmintic properties.
The aims of this project are (Aim 1) to optimize biological formulation of Cry5B protein and expression of Cry5B in probiotic B. subtilis natto, testing in vitro activity against all the parastes and in vivo activity against hookworms and whipworms in rodents and Ascaris in pigs;
(Aim 2) develop and test against all parasites the next generation Cry protein anthelmintic with promising properties, Cry14A;
and (Aim 3) investigate potential powerful synergistic drug combinations with Cry5B to delay or prevent the evolution of parasite resistance. At the conclusion of this study, we will select a delivery form of Cry5B to be advanced into pre-clinical and future clinical trials based upon 1) highest efficacy against parasites in vivo, 2) lowest delivery cost, and 3) discussions with regulators (FDA).

Public Health Relevance

Soil transmitted helminths (hookworms, whipworms, Ascaris) are major parasites of the human that cause many adverse outcomes including malnutrition, physical stunting, cognitive defects, lower earning and educational status, lethargy, immune deficiencies, adverse pregnancy outcomes, and lower productivity. Resistance and low efficacy to current drugs is growing and new therapies are urgently needed. This project will produce a new, potent, and safe therapeutic for these parasites-a biologically encapsulated protein or engineered bacterial probiotic that cures these parasites in humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI056189-10
Application #
8762206
Study Section
Drug Discovery and Mechanisms of Antimicrobial Resistance Study Section (DDR)
Program Officer
Rogers, Martin J
Project Start
2003-07-01
Project End
2019-05-31
Budget Start
2014-06-01
Budget End
2015-05-31
Support Year
10
Fiscal Year
2014
Total Cost
$521,136
Indirect Cost
$171,725
Name
University of California San Diego
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Dementiev, Alexey; Board, Jason; Sitaram, Anand et al. (2016) The pesticidal Cry6Aa toxin from Bacillus thuringiensis is structurally similar to HlyE-family alpha pore-forming toxins. BMC Biol 14:71
Durmaz, Evelyn; Hu, Yan; Aroian, Raffi V et al. (2015) Intracellular and Extracellular Expression of Bacillus thuringiensis Crystal Protein Cry5B in Lactococcus lactis for Use as an Anthelminthic. Appl Environ Microbiol 82:1286-94
Wu, Chia-Chen; Hu, Yan; Miller, Melanie et al. (2015) Protection and Delivery of Anthelmintic Protein Cry5B to Nematodes Using Mesoporous Silicon Particles. ACS Nano 9:6158-67
Schwarz, Erich M; Hu, Yan; Antoshechkin, Igor et al. (2015) The genome and transcriptome of the zoonotic hookworm Ancylostoma ceylanicum identify infection-specific gene families. Nat Genet 47:416-22
Somvanshi, Vishal S; Ellis, Brian L; Hu, Yan et al. (2014) Nitazoxanide: nematicidal mode of action and drug combination studies. Mol Biochem Parasitol 193:1-8
Hu, Yan; Ellis, Brian L; Yiu, Ying Y et al. (2013) An extensive comparison of the effect of anthelmintic classes on diverse nematodes. PLoS One 8:e70702
Hu, Yan; Miller, Melanie M; Derman, Alan I et al. (2013) Bacillus subtilis strain engineered for treatment of soil-transmitted helminth diseases. Appl Environ Microbiol 79:5527-32
Urban Jr, Joseph F; Hu, Yan; Miller, Melanie M et al. (2013) Bacillus thuringiensis-derived Cry5B has potent anthelmintic activity against Ascaris suum. PLoS Negl Trop Dis 7:e2263
Hui, Fan; Scheib, Ulrike; Hu, Yan et al. (2012) Structure and glycolipid binding properties of the nematicidal protein Cry5B. Biochemistry 51:9911-21
Hu, Yan; Aroian, Raffi V (2012) Bacterial pore-forming proteins as anthelmintics. Invert Neurosci 12:37-41

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