Development of a Cytopathic Effect-Based Phenotypic Screening Assay against Cryptosporidium

Area of Science:

• Parasitology
• Infectious Diseases
• Drug Discovery

Background:

• Cryptosporidiosis, caused by Cryptosporidium parvum (Cp) and Cryptosporidium hominis (Ch), is a significant diarrheal illness.
• Current treatments like nitazoxanide have limited efficacy, particularly in immunocompromised children, highlighting an urgent need for new therapies.
• Existing in vitro models for studying Cryptosporidium infection are often complex or not amenable to large-scale drug screening.

Purpose of the Study:

• To develop and validate novel cytopathic effect (CPE)-based assays for Cryptosporidium parvum and Cryptosporidium hominis.
• To establish a high-throughput screening (HTS) compatible model for identifying new anticryptosporidial compounds.
• To compare the performance of the new assays against traditional imaging methods.

Main Methods:

• Developed novel cytopathic effect (CPE)-based assays using human colonic tumor (HCT-8) cells for Cp and Ch infection.
• Validated the model by screening a library of FDA-approved drugs.
• Compared the developed assays to traditional imaging formats for Cryptosporidium infection.

Main Results:

• The novel CPE-based assays demonstrated a simple, functional, and homogeneous gain-of-signal format.
• The model proved amenable to high-throughput screening.
• Drug screening confirmed known anti-Cryptosporidium compounds and identified novel candidates.

Conclusions:

• The developed HCT-8 cell-based CPE assays represent a valuable tool for Cryptosporidium research.
• This model facilitates high-throughput screening for the discovery of novel anticryptosporidial drugs.
• The findings open new avenues for addressing the unmet medical need in cryptosporidiosis treatment.