Date of Award
8-19-2024
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Physiology
First Advisor
Jonathan Kirk
Abstract
Heart failure (HF) is the leading cause of death worldwide and produces an immense economic burden. Dilated cardiomyopathy (DCM), characterized by contractile weakness and chamber dilation, is a significant cause of HF. The sarcomeric proteins play a crucial role in regulating the contractile properties of the heart. As the primary motor protein, the expression of cardiac myosin isoforms (α-MHC and β-MHC) dictates the performance and cardiac energy utilization of the sarcomere. Titin is the giant spring protein in the sarcomere, and titin isoform expression impacts the passive stiffness of the myocardium. Small changes in the α-MHC/β-MHC and titin isoform ratios have been observed in the atria and ventricles in human HF and can profoundly impact the function of the heart. Unfortunately, the current techniques to quantify these isoform shifts, such as immunohistochemistry and electrophoresis have low quantitative precision and poor reproducibility. Thus, to fill this important technical and knowledge gap, we have developed a robust absolutely quantitative analytical assay for MHC and titin isoform expression patterns, using a mass spectrometry-based approach known as Multiple Reaction Monitoring (MRM). We have then performed these assays in both left atrial (LA) and left ventricular (LV) tissue from Non-Failing (NF) and DCM patients, as well as NF patients in Sinus Rhythm and with Atrial Fibrillation (AFib). Together, these data provide an accurate and absolutely quantitative reference for the expression of MHC and titin isoforms during HF and atrial fibrillation, as well as unveiling the complex proteoform landscape, which has not been previously addressed. A highly selective and sensitive assay of sarcomeric proteins is an important step for understanding the molecular mechanisms underlying cardiac dysfunction and the development of treatment for HF and atrial fibrillation.
Recommended Citation
Aima Muntu, Nitha, "Absolute Quantification of Human Myosin and Titin Isoforms in Disease by a Mass Spectrometry Approach" (2024). Master's Theses. 4526.
https://ecommons.luc.edu/luc_theses/4526
