Hepatocyte Autophagy in Malaria: Current Concepts, Emerging Mechanisms, and Future Therapeutic Directions

TL;DR

This paper explores how liver cells fight malaria parasites using a special type of autophagy and how the parasites evade this defense.

Contribution

The paper introduces a noncanonical autophagy mechanism (CASM) in hepatocytes and its role in malaria parasite defense.

Findings

Hepatocytes use CASM to activate PAAR and limit parasite development.

Plasmodium evades PAAR by sequestering LC3 and remodeling actin.

Parasites exploit host autophagy to promote lysosomal biogenesis and nutrient access.

Abstract

The liver stage of Plasmodium infection represents a critical bottleneck in malaria pathogenesis and a unique interface between parasite development and hepatocyte-intrinsic immunity. Recent evidence suggests that hepatocytes do not eliminate liver-stage parasites through canonical xenophagy, as previously assumed, but instead employ a noncanonical autophagy response known as the conjugation of ATG8 to single membranes (CASM). CASM drives rapid lipidation of LC3 onto the parasitophorous vacuole membrane (PVM) via a V-ATPase-ATG16L1-dependent mechanism, thereby activating the Plasmodium-associated autophagy-related (PAAR) response. This process represents a major hepatocyte-intrinsic mechanism that limits early liver-stage parasite development. Plasmodium liver-stage parasites have evolved specialized strategies to counteract this host defense. The PVM proteins UIS3 and UIS4 enable parasite evasion by sequestering LC3 and remodeling perivacuolar actin, thereby preventing endolysosomal fusion and inhibiting PAAR execution. In parallel, parasites selectively exploit host autophagy components—particularly GABARAP paralogs—to activate TFEB, promoting lysosomal biogenesis and improving access to host-derived nutrients. These interactions highlight autophagy as both a protective and parasite-supportive pathway, depending on the molecular context. Understanding how CASM, PAAR, and parasite evasion mechanisms intersect is crucial for designing pathway-selective interventions that amplify hepatocyte-intrinsic clearance while avoiding the inadvertent enhancement of parasite-supportive autophagy programs. Selective modulation of noncanonical autophagy offers a promising avenue for host-directed therapies that restrict liver-stage development while limiting the emergence of antimalarial resistance. This review synthesizes recent advances in the mechanistic interplay between Plasmodium liver stages and hepatocyte autophagy, identifies major knowledge gaps, and outlines future directions for translating these discoveries into therapeutic innovation.

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