R01HL160028

Mechanobiology of Cardiac Outflow Tract Morphogenesis - Proper growth, septation, and maturation of the cardiac outflow tract (OFT) into valved aortic and pulmonary outlets are essential for oxygenated circulation after birth.

1-2% of live births and up to 30% of pre-term fetal deaths have congenital heart defects, many of which affect the remodeling of the valvuloseptal primordial tissues, called the proximal and distal outflow cushions. Despite much effort uncovering the genetic basis of early OFT cushion formation, this understanding has not explained the clinically relevant phases of growth, condensation, and elongation into valves and septa.

One reason for this appears to be the domination of conditional and collective signaling mechanisms that are well accessible by genetic approaches. Mechanical forces (shear stress, pressure, tension) are ever present during this complex period of OFT growth and remodeling, but to date no studies have investigated these key interactions, especially for their contributions to OFT defects.

We believe that clinically relevant OFT remodeling arises from improper cushion endocardial and/or mesenchymal sensation of and/or response to their local mechanical environment, which in turn drives the incorrect signaling programs.

The Butcher Lab has pioneered innovative technology:

1) To quantify local in vivo mechanical forces within this OFT region and register them with local in situ gene/protein expression,
2) To non-invasively visualize and precisely ablate intracardiac tissues without collateral damage in vivo, and
3) To directly test mechanobiological mechanisms of endocardial cushion growth and remodeling ex vivo.

The preliminary data in this proposal present evidence of two mechanoregulated molecular switches that potentiate between OFT cushion proliferation and differentiation, which motivates the novel hypothesis that local mechanosensation operates molecular switches to control sizing, shape, and stratification of the outflow valves and septa.

Aim 1 will implement innovative non-invasive laser photoablations of the formed proximal or distal cushions of the avian OFT to create genetically unbiased clinically relevant outflow tract malformations. We will then quantitatively analyze and register their hemodynamic, morphological, and phenotypic changes. We will further apply novel deconvolution integration of single-cell RNA sequencing (SC-SEQ) and spatially resolved transcriptomics (SLIDE-SEQ) to reveal unprecedented spatio-temporal resolution of the cellular course of malformation and elaborate how known and newly discovered molecular regulatory programs associate with local mechanical stress changes.

Aim 2 will test the mechanistic causality of the mechanotransduction-operated molecular switches in the OFT cushion endocardium via shear stress patterns.

Aim 3 will test the operation of different mechanobiological switches in cushion mesenchyme via tension/compression using high-throughput ex vivo organ cultures.

The findings from these studies will substantially advance our understanding of mechanoregulation and conditional signaling in outflow tract valvuloseptal maturation, paving the way for strategies to manipulate such signaling programs to reduce or even rescue congenital heart defect severity in utero.

Cornell University

TO FOSTER HEART AND VASCULAR RESEARCH IN THE BASIC, TRANSLATIONAL, CLINICAL AND POPULATION SCIENCES, AND TO FOSTER TRAINING TO BUILD TALENTED YOUNG INVESTIGATORS IN THESE AREAS, FUNDED THROUGH COMPETITIVE RESEARCH TRAINING GRANTS. SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM: TO STIMULATE TECHNOLOGICAL INNOVATION, USE SMALL BUSINESS TO MEET FEDERAL RESEARCH AND DEVELOPMENT NEEDS, FOSTER AND ENCOURAGE PARTICIPATION IN INNOVATION AND ENTREPRENEURSHIP BY SOCIALLY AND ECONOMICALLY DISADVANTAGED PERSONS, AND INCREASE PRIVATE-SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT FUNDING. SMALL BUSINESS TECHNOLOGY TRANSFER (STTR) PROGRAM: TO STIMULATE TECHNOLOGICAL INNOVATION, FOSTER TECHNOLOGY TRANSFER THROUGH COOPERATIVE R&D BETWEEN SMALL BUSINESSES AND RESEARCH INSTITUTIONS, AND INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL R&D.

93.837 - Cardiovascular Diseases Research

National Heart Lung and Blood Institute (NHLBI) [HHS - NIH]

Ithaca, New York 14850 United States

Single Zip Code

NIH Research Project Grant (Parent R01 Clinical Trial Not Allowed) (PA-20-185)

Amendment Since initial award the total obligations have increased 323% from $725,112 to $3,068,575.