Key result
High-throughput drug screening fails to identify reproducible therapies for fbn3-deficient zebrafish cardiac phenotypes.
Why the study?
Current medical therapies for Marfan syndrome slow disease progression but do not prevent major complications, underscoring the need for new treatment strategies and unbiased discovery approaches.
Do standard Marfan syndrome therapies, TGF-β signaling inhibitors, or clinically approved library compounds reduce cardiac stress, pericardial edema, and bulbus arteriosus dilation in a fbn3−/− zebrafish model of Marfan syndrome?
Do standard Marfan syndrome therapies, TGF-β signaling inhibitors, or clinically approved library compounds reduce cardiac stress, pericardial edema, and bulbus arteriosus dilation in a fbn3−/− zebrafish model of Marfan syndrome?
This study establishes a highly sensitive secreted nanoluciferase zebrafish platform (~1,000-fold dynamic range) for quantifying cardiovascular stress in Marfan syndrome, revealing that standard therapies, TGF-β inhibitors, and over 1,500 approved drugs fail to rescue early structural cardiovascular defects in fbn3−/− mutants.
No validated rescues emerged from 1,520 compounds in this zebrafish model; leaves open whether refined platforms or expanded libraries will identify Marfan therapies.
Background Marfan syndrome (MFS) is a life-threatening heritable connective tissue disorder caused by pathogenic variants in fibrillin-1, characterized by progressive cardiovascular disease. Current medical therapies slow disease progression but do not prevent major complications, underscoring the need for new treatment strategies and unbiased discovery approaches. Methods We used a zebrafish model of MFS lacking fibrillin-3 ( fbn3 −/− ), which recapitulates key cardiovascular phenotypes including cardiac stress, valvular defects, arrhythmia, and aortic dilation. To enable sensitive, quantitative assessment of cardiac stress, we generated a novel transgenic zebrafish reporter expressing secreted nanoluciferase under control of the stress-responsive nppb promoter. This reporter was combined with morphological phenotyping and bulbus arteriosus imaging. We evaluated standard MFS therapies, targeted modulators of TGF-β signaling, and performed an unbiased high-throughput drug screen of over 1 500 clinically approved compounds across multiple developmental treatment windows. Results fbn3 −/− larvae exhibited markedly elevated nppb activity that correlated with phenotypic severity and peaked during stages of highest mortality. The nanoluciferase reporter provided a ~ 1 000-fold dynamic range, substantially outperforming Firefly luciferase-based assays. Pharmacological inhibition of TGF-β signaling produced transient or deleterious effects, while β-blockers, losartan, and allopurinol failed to consistently improve cardiac stress, pericardial edema, or BA dilation. The unbiased high-throughput drug screen identified a small number of primary and secondary hits; however, none demonstrated reproducible phenotypic rescue upon rigorous multi-dose, multi-time window validation. Conclusions This study establishes a sensitive zebrafish-based platform for early, quantitative assessment of cardiovascular stress in MFS. Our findings highlight the limited efficacy of current therapies, the context-dependent nature of TGF-β modulation, and the biological complexity underlying MFS pathogenesis. Although no definitive therapeutic candidates were identified, this work lays a robust foundation for expanded unbiased discovery efforts aimed at identifying disease-modifying interventions for MFS.
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Horvat et al. (2026) studied Marfan syndrome. High-throughput drug screen (1,520 FDA-approved compounds) and targeted therapies (refametinib, RepSox, β-blockers, losartan, allopurinol) vs. Untreated or DMSO solvent-treated fbn3-/- mutant and wild-type zebrafish larvae was evaluated on Cardiac stress measured by nppb promoter-driven secreted nanoluciferase (secNluc) luminescence, alongside pericardial edema severity and bulbus arteriosus diameter. High-throughput screening of 1,520 compounds and standard therapies yielded a 1.3% primary hit rate (Z-score < -1) but 0 reproducibly validated candidates for rescuing fbn3-/- zebrafish phenotypes.
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