High-Throughput Cardiac Hypertrophy Phenotyping Supports Lead Optimization of GRK5 Inhibitors

Area of Science:

• Cardiovascular Biology
• Pharmacology
• Biotechnology

Background:

• Cardiac hypertrophy is a key factor in heart failure progression, with limited therapeutic strategies to reverse pathological remodeling.
• Novel approaches are needed to identify effective treatments for cardiac hypertrophy and improve heart failure outcomes.

Purpose of the Study:

• To develop and validate a high-throughput phenotypic screening assay for cardiac hypertrophy.
• To utilize the assay to identify and characterize inhibitors of G protein-coupled receptor kinase 5 (GRK5) as a potential therapeutic target.

Main Methods:

• Established a mixed neonatal rat heart cell culture for simultaneous assessment of cardiomyocytes and noncardiomyocytes.
• Developed customized CellProfiler-based image analysis to extract multiparametric morphological data, creating a quantitative "Hypertrophy Score."
• Applied the assay to screen a focused collection of GRK5 inhibitors, correlating biochemical and cellular data.

Main Results:

• The assay successfully quantified cellular responses to GRK5 inhibition in a physiologically relevant microenvironment.
• Structure-activity and -property relationships indicated that lipophilic and covalently reactive compounds negatively impacted cellular efficacy.
• Potent GRK5 inhibition over GRK2 and GRK6 was confirmed, with diastereomers 4a/b identified as valuable chemical probes.

Conclusions:

• The developed high-throughput assay is effective for lead optimization in cardiac hypertrophy research.
• GRK5 is a validated therapeutic target, and specific chemical probes have been identified for further investigation.
• Understanding structure-property relationships is crucial for developing effective GRK5 inhibitors for cardiac hypertrophy.