Drug Repurposing Screen Identifies 70 Existing Compounds, Including Beta-Lactam Antibiotics, That Block Deadly Hantavirus Infections
核心洞察
A high-throughput screen of 5,256 FDA-approved and clinical compounds identified 70 validated host-directed therapies that suppress Puumala orthohantavirus (搜索) (PUUV) infection across human lung and endothelial cells.
Among the validated hits, beta-lactam antibiotics such as cefodizime demonstrated unexpected antiviral activity, representing a novel and low-toxicity therapeutic angle against hantaviruses.
Functional clustering revealed enrichment of IMPDH (搜索) inhibitors, mTOR (搜索) pathway inhibitors, and HSP90 (搜索) chaperone inhibitors, confirming key host pathways essential for viral replication.
A landmark drug-repurposing study has identified 70 existing compounds capable of suppressing Puumala orthohantavirus (搜索) (PUUV) infection, including the unexpected discovery that common beta-lactam antibiotics possess potent antiviral properties. Published in Scientific Reports, the research screened 5,256 FDA-approved, clinical, and pre-clinical small molecules from the Drug Repurposing Hub library using a live-virus phenotypic assay, offering a fast-tracked therapeutic pipeline for diseases that currently lack any approved pharmacological intervention.
Orthohantaviruses are rodent-borne, negative-sense RNA viruses that cause two severe human diseases: hantavirus pulmonary syndrome (HPS), endemic to the Americas with a case fatality rate of 30% to 40%, and hemorrhagic fever with renal syndrome (HFRS), prevalent across Europe and Asia with mortality rates typically below 1% but reaching up to 10% for certain strains. PUUV is the most common hantavirus in Europe and the primary pathogen responsible for HFRS. Despite decades of research, no EMA- or FDA-approved vaccine or hantavirus-specific treatment exists, leaving clinicians with only supportive symptom management.
A scalable, automated screening platform
To overcome limitations of prior hypothesis-driven studies, researchers developed an automated, microscopy-based platform to observe live PUUV interacting with human host cells. The assay employed A549 human lung adenocarcinoma epithelial cells for primary screening, with subsequent validation in primary human umbilical vein endothelial cells (HUVECs) to replicate the virus's known tropism for human blood vessels.
Cells were incubated with library compounds at 10 µM for six hours, followed by direct addition of PUUV at a multiplicity of infection (MOI) of 3. After 24 hours, cells were fixed and immunostained using convalescent patient sera to detect viral proteins, with Hoechst 33342 and CellTracker dyes marking nuclei and cell bodies respectively. High-content automated microscopy and CellProfiler image analysis quantified the ratio of infected cells to total viable cells.
The screening assay demonstrated robust performance, with an initial Z-prime of 0.7 and an average Z-prime of 0.41 across the full-scale screen. The mean infection rate was 17.7% with limited batch-to-batch variation. Control treatments, including the antiviral drug Ribavirin, significantly reduced baseline infection rates (p < 0.0001).
From 151 candidates to 70 validated hits
Of the 5,256 molecules tested, 151 were identified as candidate antiviral drugs, each decreasing the infection rate at least two-fold compared to vehicle controls while maintaining at least 50% cell viability. Additionally, 23 proviral candidates—including histone deacetylase (HDAC (搜索)) inhibitors such as CI994—significantly increased the number of infected cells by up to 400%.
Multi-dose validation trials at 0.83 µM, 2.5 µM, and 10 µM confirmed 70 of the primary antiviral hits. Among these, 34 compounds demonstrated robust activity in both A549 cells and HUVECs, while 25 were specifically active in A549 lung cells and 11 showed a preference for HUVEC vascular cells. For the proviral candidates, 21 of 23 primary hits were validated, predominantly in the A549 cell line.
Functional clustering reveals key host dependencies
The validated antiviral hits clustered into distinct biological mechanisms. Nucleotide biosynthesis inhibitors, particularly inosine monophosphate dehydrogenase (IMPDH (搜索)) blockers such as mycophenolic acid and its derivatives, constituted a major class. "Our identification of multiple IMPDH inhibitors that suppress PUUV-infection in both A549 cells and HUVECs is therefore consistent with prior work and show that nucleotide availability is important for hantavirus replication," the authors noted.
mTOR (搜索) signaling inhibitors formed another recurrent class, with preferential efficacy observed in A549 cells compared with HUVECs—suggesting that the impact of mTOR modulation on PUUV infection may depend on baseline cellular state or cell-type-specific coupling of translational control to antiviral responses. Heat shock protein (HSP) inhibitors, particularly those targeting HSP90 (搜索), also emerged among validated hits, supporting a role for proteostasis networks in hantavirus infection.
Beta-lactam antibiotics: an unexpected antiviral discovery
Among the most striking findings was the identification of several beta-lactam antibiotics, including cefodizime, as effective and low-toxicity antiviral compounds. "To our knowledge, antiviral activity of beta-lactam antibiotics has not been reported previously," the researchers stated. "Given the reproducibility of our findings and the identification of multiple compounds from this class, this observation warrants further investigation."
The proviral compounds, meanwhile, showed enrichment of epigenetic modifiers—particularly HDAC (搜索) inhibitors. The researchers noted that the proviral effect could only be verified in A549 cells, as the substantially higher infection rate in HUVECs (~80% versus ~20%) precluded analysis of infection enhancement in that system.
A prioritized pipeline for a neglected threat
The study represents a shift from narrow, hypothesis-driven exploration to a systematic blueprint of host-virus dependencies. The 70 clinical-ready candidates provide an immediate, prioritized pipeline for animal model validation, bringing the field closer to the first authorized treatment for orthohantavirus-caused diseases.
"The results from our drug repurposing screen are largely concordant with existing knowledge on host-directed antiviral strategies in the hantavirus field," the authors concluded. "In addition, our work has identified novel host dependencies during hantavirus infection that remain largely unexplored. As such, it provides a reference framework for prioritising host pathways for further mechanistic studies and for exploring new therapeutic avenues."