J. Carter Ralphe, MD

Position title: Associate Professor of Pediatrics; Division Chief of Pediatric Cardiology

Email: jcralphe@pediatrics.wisc.edu

Phone: (608) 262-1603

J. Carter Ralphe

Link to Ralphe Lab

Research

The Ralphe Lab is interested in understanding how mutations in genes encoding important regulatory proteins within cardiac cells lead to the development of hypertrophic cardiomyopathy. Studies focus primarily on mutations in cardiac myosin binding protein C (cMyBP-C), a protein that regulates contractility and functional reserve of the heart. Mutations in cMyBP-C are recognized as a leading cause of familial hypertrophic cardiomyopathy.

Current approaches employ a novel 3D engineered cardiac tissue model using late fetal or early neonatal mouse cardiomyocytes from which  molecular, metabolic, and contractile data are gathered. Using human-derived induced pluripotent stem cells (iPS cells), cardiomyocytes from individuals carrying specific HCM-associated mutations can be studied. The Ralphe Lab’s living integrated cardiac tissue model can be applied to understanding normal and abnormal physiology as well as identifying the impact of known or unknown compounds on cardiac performance.

The lab is equipped with standard and high-throughput molecular tools as well as two physiology work stations that measure muscle contractility (twitch force amplitude and kinetics of contraction and relaction). The first is equipped with a high speed length controller to dynamically mimic loading conditions and a force transducer integrated with an IonOptix system for measuring dynamic intracellular signaling events including calcium transients and NADH oxidation. The second station is designed to measure oxygen consumption and metabolic activity while gathering simultaneous force data. With these tools we can measure simultaneous intracellular events and integrated tissue contractile performance.