Targeting fungal BET bromodomains as a pan-Candida antifungal strategy

Wei, K.; Overhulse, J. M.; Arlotto, M.; Zhou, Y.; Dupper, N. J.; Kashemirov, B. A.; Garnaud, C.; Bourgine, G.; Cornet, M.; Rabut, G.; McKenna, C. E.; Petosa, C.; Govin, J.

doi:10.1101/2023.02.03.527073

bioRxiv · 10.1101/2023.02.03.527073

Targeting fungal BET bromodomains as a pan-Candida antifungal strategy

Wei, K.·Overhulse, J. M.·Arlotto, M.·Zhou, Y.·Dupper, N. J.·Kashemirov, B. A.·Garnaud, C.·Bourgine, G.·Cornet, M.·Rabut, G.·McKenna, C. E.·Petosa, C.·Govin, J.

View original source ↗Export metadata ↓

Abstract

Small molecules that target one or both bromodomains (BDs) of human BET proteins are intensely studied as potential new therapeutics against cancer, diabetes and other diseases. The BDs of the fungal BET protein Bdf1 are essential for the human fungal pathogen Candida albicans, suggesting BET inhibition as a potential antifungal strategy. However, while the inactivation of both Bdf1 BDs is lethal, that of a single BD only modestly affects viability, implying the need to develop antifungal compounds that selectively target both Bdf1 BDs without inhibiting human BDs. Here, we investigate Bdf1 as a potential antifungal target in Candida glabrata, an invasive Candida species phylogenetically distant from C. albicans and of increasing medical concern. We show that Bdf1 BD functionality is essential in C. glabrata and identify a phenyltriazine derivative that targets both Bdf1 BDs with selectivity over human BET BDs. We show that human BET BDs can functionally replace Bdf1 BDs in C. glabrata and we use the humanized strains to demonstrate on-target antifungal activity of the phenyltriazine compound. Moreover, by exploiting the humanized and parental fungal strains we identified BET inhibitor I-BET726 to have potent antifungal activity against a broad spectrum of Candida species, including azole- and echinocandin-resistant clinical C. albicans and C. glabrata isolates. Crystal structures suggest how to improve the potency and selectivity of these compounds. Taken together, our findings provide compelling support for the development of BET inhibitors as potential pan-Candida antifungal therapeutics.

Explore related subjects

biochemistry Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Wei, K., Overhulse, J. M., Arlotto, M., Zhou, Y., Dupper, N. J., Kashemirov, B. A., Garnaud, C., Bourgine, G., Cornet, M., Rabut, G., McKenna, C. E., Petosa, C., Govin, J.. 2023-02-04. Targeting fungal BET bromodomains as a pan-Candida antifungal strategy. https://doi.org/10.1101/2023.02.03.527073

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

The structures of two intermediates en route to DNA repair within a (6-4) photolyase

Pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) are mutagenic DNA lesions produced when UV light crosslinks two adjacent pyrimidine bases. These lesions must be repaired to maintain genome integrity, a function executed by the (6-4) photolyase enzymes. This repair chemistry is complex, involving the transfer of a hydroxyl group from one base to another, accompanied or followed by cleavage of an interbase bond. It remains unclear how the enzyme orchestrates this reaction. Typically, models invoke a stepwise process in which an oxetane intermediate is transiently populated, but despite over thirty years of investigation, such an intermediate has never been definitively observed. Conducting dose-controlled X-ray crystallography on the (6-4) photolyase from Vibrio cholerae, we observed the transformation of 6-4PP into an oxetane species. Furthermore, we identified a previously unanticipated hemi-cleaved intermediate. The progressive transformation of 6-4PP into oxetane, hemi-cleaved, and fully repaired species requires a reexamination of the existing models of DNA repair by (6-4) photolyases.

biochemistry↗

bioRxiv2026

Endothelial protein C receptor is an entry receptor for Langya virus

Langya virus (LayV) was recently discovered in infected individuals with febrile illness and classified as a Parahenipavirus, a group of poorly understood pathogens. LayV is distantly related to Nipah henipavirus which causes recurring outbreaks with case fatality rates reaching up to 90%. No vaccines or therapeutics are approved for use in humans for any parahenipavirus or henipavirus despite their broad geographic distribution and pandemic potential. Here, we discovered that human endothelial protein C receptor (EPCR) is an entry receptor for LayV and that the tetrameric LayV attachment glycoprotein (G) binds EPCR avidly. We reveal the molecular basis of LayV G recognition of the EPCR receptor and provide a blueprint of the determinants of receptor ortholog usage. We found that human and shrew EPCR orthologs promote cell entry of LayV and of the closely related Mojiang pseudoviruses. These results along with the detection of several Parahenipaviruses in shrews set these pathogens apart from Henipaviruses, which use Pteropid fruit bats as reservoir hosts. Our data support future surveillance efforts, by enabling prediction of EPCR utilization among newly discovered Parahenipaviruses, and the development and evaluation of countermeasures targeting this emerging group of human pathogens.

biochemistry↗

bioRxiv2026

RNA-targeted aminopyridine compounds provide a new antifungal strategy

While RNA is an emerging therapeutic target class, progress is limited by a shortage of well-defined targets in which ligand binding is coupled to measurable function. The group I intron, a self-splicing ribozyme essential in fungal mitochondria but absent from humans, offers both a tractable platform for exploring first principles of small molecule-RNA targeting and a selective antifungal target. We recalibrated an intron-splicing assay to approximate cellular conditions and performed an extensive, cryo-EM-guided structure-activity relationship campaign against the Candida albicans mtLSU intron. Ligands containing a flexible diamine outperformed conformationally constrained analogues, suggesting a general principle for engaging dynamic RNA surfaces and yielding lead aminopyridine 56 (IC 21.6 nM). Compound 56 synergizes with amphotericin B against C. albicans, suggesting a path for combination therapies. RT-qPCR confirmed direct target engagement in cells. This work establishes the fungal group I intron as a viable, mechanistically distinct antifungal target and a model platform for RNA-targeted discovery.

biochemistry↗