Protocol for isolation of nuclei from murine cardiac tissue for single-nucleus multiomic sequencing

Pathological cardiac remodeling involves cell-type-specific regulatory changes that require integrative analysis across all cardiac cell populations. Here, we present a protocol for isolating single nuclei from fresh-frozen murine cardiac ventricular tissue to enable the integrated analysis of gene expression and chromatin accessibility. We describe steps for mechanical homogenization, sequential filtration, sucrose cushion purification, and fluorescence-activated nuclei sorting (FANS). This protocol enables multiomic analysis across various cardiac cell types and supports epigenomic studies of gene regulation.