SUMMARY
Metabolism plays key roles in regulating cell fate and function during normal development and under stress
conditions in all tissues and organs. For example, metabolic reactive oxygen species (ROS) are important
signaling molecules that can promote cardiomyocyte differentiation; yet how the cell translates redox signals
into functional cellular outcomes is poorly understood. Moreover, faulty regulation of this process underpins
cardiac-related illness including congenital heart defects (CHD) and heart failure (HF), making this question of
particular clinical relevance. Based on our preliminary data and extensive literature analysis, we hypothesize
that NADPH oxidase 4 (Nox4), an enzyme that provides the major source of metabolically generated
H2O2 acts as a central hub for sarcomere assembly during heart development. Our proposal is novel and
innovative for several reasons: 1) we will employ human induced pluripotent stem cell-derived cardiomyocytes
(hiCMs) strategy as a model allowing us to test the role of Nox4 during cardiac lineage commitment, and 2) we
have adapted state-of-the-art imaging, genetic, and optogenetic approaches, 3) to test how cellular metabolism
is coupled to sarcomere assembly, the functional unit of the cardiac muscle. Specifically, by combining genetic
perturbation studies and nanoscale resolution imaging approaches, we will test the role of Nox4 sarcomere
assembly as well as the requirement of Nox4’s catalytic activity and mitochondrial localization during CM
differentiation (Aim 1), we will test the hypothesis that Nox4 initiates sarcomere formation by regulation of focal
adhesion kinase (FAK) at FA-like structures called protocostameres (Aim 2), and we will employ novel state-
of-the art genetic and optogenetic tools to derive quantitative insights into how Nox4 regulates CM
differentiation and contractility in live cells (Aim 3). Our results will fill a major gap in our knowledge of how
cellular metabolism informs CM maturation and it will also identify key players in this process. Importantly, this
work will be performed in a human cell-based model system, which may expedite the development of new
therapies for the treatment of cardiac disease.
The fellowship training plan leverages the expertise of Dr. Laurie Boyer along with a number of collaborations
within the MIT community, including the lab of Dr. Ed Boyden. Dr. Boyer is a pioneer in understanding the
molecular mechanisms that drive cell fate decisions. We have also recently worked with experts in vertebrate
cardiac developmental biology including Dr. Caroline Burns to gain a deeper understanding of the conserved
mechanisms underpinning regulation of sarcomere structure. Therefore, I will receive world class training in
diverse areas including molecular and cellular biology as well as genetics in both in vitro and in vivo cardiac
model systems. The environment and resources at MIT will greatly facilitate the success of the proposed aims
and my development as an independent researcher.