Background and Aims: HEV infection is the most common cause of liver inflammation, but the pathogenic mechanisms remain largely unclear. We aim to explore whether HEV infection activates inflammasomes, crosstalk with antiviral interferon response, and the potential of therapeutic targeting. Approach and Results: We measured IL‐1β secretion, the hallmark of inflammasome activation, in serum of HEV‐infected patients and rabbits, and in cultured macrophage cell lines and primary monocyte‐derived macrophages. We found that genotypes 3 and 4 HEV infection in rabbits elevated IL‐1β production. A profound increase of IL‐1β secretion was further observed in HEV‐infected patients (1,733 ± 1,234 pg/mL; n = 70) compared to healthy persons (731 ± 701 pg/mL; n = 70). Given that macrophages are the drivers of inflammatory response, we found that inoculation with infectious HEV particles robustly triggered NOD‐like receptor family pyrin domain‐containing 3 (NLRP3) inflammasome activation in primary macrophages and macrophage cell lines. We further revealed that the ORF2 capsid protein and the formed integral viral particles are responsible for activating inflammasome response. We also identified NF‐κB signaling activation as a key upstream event of HEV‐induced NLRP3 inflammasome response. Interestingly, inflammasome activation antagonizes interferon response to facilitate viral replication in macrophages. Pharmacological inhibitors and clinically used steroids can effectively target inflammasome activation. Combining steroids with ribavirin simultaneously inhibits HEV and inflammasome response without cross‐interference. Conclusions: HEV infection strongly activates NLRP3 inflammasome activation in macrophages, which regulates host innate defense and pathogenesis. Therapeutic targeting of NLRP3, in particular when combined with antiviral agents, represents a viable option for treating severe HEV infection.

The emergence of Rocahepevirus ratti genotype 1 (rat hepatitis E virus; rat HEV) in humans presents an unprecedented threat; however, the risk of rat HEV transmission to humans is not well understood. Here, we report the “Distinguishing Antibody Response Elicitation (DARE)” method, which distinguishes exposure to rat HEV. We use four study sets from China for large-scale population analysis: set 1 (hospital visit) and set 3 (ALT abnormality) from Yunnan province, a biodiversity hotspot, and set 2 (received physical examination) and set 4 (ALT abnormality) from Jiangsu province, a non-hotspot control region. rat HEV exposure risk is significantly higher in Yunnan, with 21.97% (190 of 865) in set 1 and 13.97% (70 of 501) in set 3, compared to 0.75% (9 of 1196) in Jiangsu’s set 2. Six spillover infections for rat HEV are identified in set 1, with one case of abnormal ALT. The rat-1d strains carried by rats are closely related to those human infections. Our study reveals the substantial spillover burden posed by rat HEV in biodiversity hotspots and highlights the utility of DARE method for proactive surveillance of public health emergencies.

Background: Hepatitis E virus (HEV), the leading global cause of acute viral hepatitis, lacks robust in vitro models for virology and pathogenesis research. Objective: We evaluated induced pluripotent stem cell (iPSC)-induced human liver, intestinal and brain organoids (hLOs, hIOs and hBOs) as platforms for HEV infection and replication. Methods: Multilineage organoids were infected with clinical HEV genotypes 1, 3 and 4. Viral tropism, host responses and antiviral efficacy were assessed. Results: All organoids supported the complete life cycle of HEV. hLOs exhibited infection in hepatocytes, cholangiocytes, macrophages and stellate cells, accompanied by elevated interleukin-6 levels, impaired hepatic function (reduced secretion of albumin and Factor IX) and increased levels of alanine aminotransferase and aspartate aminotransferase, indicating hepatocellular injury. hIOs demonstrated broad epithelial (enterocyte, goblet, Paneth and endocrine) and mesenchymal infection, with disrupted barrier function (loss of tight junction proteins), proinflammatory cytokines upregulation and initiation of epithelial–mesenchymal transition. hBOs showed neuronal tropism, infecting glutamatergic, dopaminergic and GABAergic neurons, as well as astrocytes and oligodendrocytes. An increased number of TH ⁺ dopaminergic neurons was observed. Ribavirin treatment in all three models partially reversed this phenotype. Conclusion: This study established iPSC-induced multilineage organoid infection models, confirming HEV’s capacity for pan-tissue infection and revealing potential pathogenic mechanisms in the liver, intestine and nervous system. This platform provides valuable tools for HEV virology research and antiviral drug development, underscoring the unique value of organoid technology in infectious disease research.

Hepatitis E, an infectious disease caused by hepatitis E virus (HEV) infection is currently the major acute viral hepatitis problem worldwide. HEV is a single-stranded positive sense RNA virus main...