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Biology subjects

Karl, N.

Publications and source records attributed to Karl, N..

3 recordsLinked to original sources

PERK inhibition rewires translational and CMGC protein kinase networks into an antiviral state

Protein kinases (PKs) are central regulators of cellular signaling, yet only a small fraction of the human kinome is targeted therapeutically, and kinase-substrate relationships remain incompletely defined. Here, we systematically characterize kinome regulation during human coronavirus 229E (HCoV-229E) infection across transcriptomic, translational, proteomic, and phospho-proteomic layers. We reveal that pharmacological inhibition of the ER stress sensor kinase PERK reprograms host protein biosynthesis and phospho-proteomic landscapes, simultaneously blocking viral nucleocapsid phosphorylation and modulating multiple host kinases. This rewiring antagonizes virus-induced translational shutdown, along with pronounced regulation of the CMGC kinase family, a pattern conserved in SARS-CoV and SARS-CoV-2 infected cells. Comparative analyses with PERK depletion distinguish on-target from off-target effects of PERK inhibition. Our findings uncover the kinome-scale consequences of PERK perturbation in coronavirus infection and demonstrate how the polypharmacology of PERK inhibitors can be harnessed to establish a potent antiviral state, revealing new avenues for host-directed antiviral strategies.

systems biology↗

The rocaglate CR-31-B (-) inhibits SARS-CoV-2 replication at non-cytotoxic, low nanomolar concentrations in vitro and ex vivo

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a betacoronavirus in the subgenus Sarbecovirus causes a respiratory disease with varying symptoms referred to as coronavirus disease 2019 (COVID-19) and is responsible for a pandemic that started in early 2020. With no vaccines or effective antiviral treatments available, and infection and fatality numbers continuing to increase globally, the quest for novel therapeutic solutions remains an urgent priority. Rocaglates, a class of plant-derived cyclopenta[b]benzofurans, exhibit broad-spectrum antiviral activity against positive- and negative-sense RNA viruses. This compound class inhibits eukaryotic initiation factor 4A (eIF4A)-dependent mRNA translation initiation, resulting in strongly reduced viral RNA translation. The synthetic rocaglate CR-31-B (-) has previously been shown to inhibit the replication of human coronaviruses, such as HCoV-229E and MERS-CoV, as well as Zika-, Lassa-, Crimean Congo hemorrhagic fever virus in primary cells. Here, we assessed the antiviral activity of CR-31-B (-) against SARS-CoV-2 using both in vitro and ex vivo cell culture models. In African green monkey Vero E6 cells, CR-31-B (-) inhibited SARS-CoV-2 replication with an EC50 of ~1.8 nM. In line with this, viral protein accumulation and replication/transcription complex formation were found to be strongly reduced by this compound. In an ex vivo infection system using human airway epithelial cells, CR-31-B (-) was found to cause a massive reduction of SARS-CoV-2 titers by about 4 logs to nearly non-detectable levels. The data reveal a potent anti-SARS-CoV-2 activity by CR-31-B (-), corroborating previous results obtained for other coronaviruses and supporting the idea that rocaglates may be used in first-line antiviral intervention strategies against novel and emerging RNA virus outbreaks.

molecular biology↗

Inhibiting coronavirus replication in cultured cells by chemical ER stress

Coronaviruses (CoVs) are important human pathogens for which no specific treatment is available. Here, we provide evidence that pharmacological reprogramming of ER stress pathways can be exploited to suppress CoV replication. We found that the ER stress inducer thapsigargin efficiently inhibits coronavirus (HCoV-229E, MERS-CoV, SARS-CoV-2) replication in different cell types, (partially) restores the virus-induced translational shut-down, and counteracts the CoV-mediated downregulation of IRE1 and the ER chaperone BiP. Proteome-wide data sets revealed specific pathways, protein networks and components that likely mediate the thapsigargin-induced antiviral state, including HERPUD1, an essential factor of ER quality control, and ER-associated protein degradation complexes. The data show that thapsigargin hits a central mechanism required for CoV replication, suggesting that thapsigargin (or derivatives thereof) may be developed into broad-spectrum anti-CoV drugs. One Sentence Summary / Running titleSuppression of coronavirus replication through thapsigargin-regulated ER stress, ERQC / ERAD and metabolic pathways

immunology↗