Host-based Prophylaxis Successfully Targets Liver Stage Malaria Parasites.

Area of Science:

• Malariology
• Drug Discovery
• Hepatology

Background:

• Malaria elimination requires targeting the asymptomatic liver stages (LSs) of Plasmodium parasites.
• Primaquine is the only licensed drug effective against all LSs, limiting prophylactic options.
• Host-directed therapies offer a novel strategy to expand antimalarial drug development.

Purpose of the Study:

• To investigate the efficacy of Bcl-2 inhibitors and P53 agonists against malaria liver-stage parasites.
• To determine if these host-targeting drugs can prevent blood-stage malaria development.
• To assess the safety profile of these drug classes in preclinical models.

Main Methods:

• Utilized a mouse malaria model to test Bcl-2 inhibitors and P53 agonists in vitro and in vivo.
• Assessed parasite burden reduction and induction of apoptosis in infected hepatocytes.
• Evaluated drug efficacy in humanized mice infected with Plasmodium falciparum.

Main Results:

• Both Bcl-2 inhibitors and P53 agonists significantly reduced malaria LS burden.
• Bcl-2 inhibitors induced apoptosis in infected hepatocytes; P53 agonists acted independently of apoptosis.
• Combined therapy showed synergistic effects, delaying or preventing blood-stage disease onset.
• Effective at non-toxic doses, with efficacy demonstrated in humanized mice.

Conclusions:

• Host-targeting drugs, including Bcl-2 inhibitors and P53 agonists, represent a promising new strategy for malaria prophylaxis.
• These agents effectively eliminate liver-stage malaria parasites with a favorable safety profile.
• This approach opens a new avenue for developing interventions to prevent malaria transmission and disease.