Targeting translation initiation yields fast-killing therapeutics against the zoonotic parasite Cryptosporidium...

Area of Science:

• Parasitology
• Molecular Biology
• Drug Discovery

Background:

• Cryptosporidium parvum is a zoonotic parasite causing significant diarrheal disease in vulnerable populations.
• Current treatments for cryptosporidiosis are limited, necessitating novel therapeutic strategies.
• The parasite's eukaryotic initiation factor 4A (CpeIF4A) is crucial for protein synthesis.

Purpose of the Study:

• To identify and validate CpeIF4A as a therapeutic target for Cryptosporidium parvum.
• To evaluate the efficacy of Rocaglamide A (Roc-A) as a potential anti-cryptosporidial agent.

Main Methods:

• Investigated Roc-A binding affinity to the CpeIF4A-RNA-ATP complex.
• Assessed Roc-A's impact on protein synthesis in excysting sporozoites.
• Evaluated Roc-A's efficacy in host-cell culture and in vivo mouse models (interferon-γ-knockout and NCG mice).

Main Results:

• Roc-A demonstrated high-affinity binding to CpeIF4A (Kd = 33.7 nM) and inhibited protein synthesis (IC50 ≈ 3.7 µM).
• Roc-A exhibited potent inhibition of intracellular parasite growth (EC50 = 1.77 nM) with high selectivity indices in host cells.
• Oral administration of Roc-A significantly reduced oocyst shedding in mouse models without rebound.

Conclusions:

• CpeIF4A is a druggable target for developing new anti-cryptosporidial therapies.
• Roc-A is a promising lead compound for treating cryptosporidiosis.
• Targeting translation initiation represents a novel and effective strategy against Cryptosporidium parvum infections.