CRISPR/Cas9 Screens Implicate RARA and SPNS1 in Doxorubicin Cardiotoxicity

Area of Science:

• Genomics
• Cardiology
• Drug Discovery

Background:

• Doxorubicin (DOX) is a chemotherapy agent known to induce cardiotoxicity and heart failure.
• The precise molecular mechanisms underlying DOX-induced cardiotoxicity remain incompletely understood.

Purpose of the Study:

• To employ a functional genomics approach to comprehensively identify genetic modifiers of DOX-induced cardiotoxicity.
• To uncover novel molecular pathways and potential therapeutic targets for mitigating DOX-induced heart damage.

Main Methods:

• Utilized genome-wide and targeted CRISPR/Cas9 screening in cardiomyocyte models.
• Performed RNA-Sequencing to analyze gene expression changes.
• Investigated genetic factors influencing DOX uptake, transport, and efflux.

Main Results:

• Loss of Retinoic Acid Receptor Alpha (RARA) exacerbated DOX-induced cell death; RARA activation with tamibarotene conferred protection.
• Tamibarotene treatment counteracted DOX-induced suppression of metabolic and mitochondrial gene expression.
• Disruption of lysosome homeostasis (e.g., SPNS1 deficiency) led to DOX hyperaccumulation and increased toxicity, while ribosome dysfunction and nutrient deprivation reduced DOX toxicity.

Conclusions:

• Identified key drug-gene interactions elucidating DOX cardiotoxicity mechanisms.
• Highlighted RARA and lysosome homeostasis as critical players in DOX response.
• Established a functional genomics framework for discovering therapeutic targets and biomarkers for DOX cardiotoxicity.