Cardiovascular diseases are leading causes of morbidity and mortality. One such disease is left ventricular noncompaction (LVNC), in which trabeculae fail to undergo compaction. Trabeculae are sheet-like structures extending from the myocardium to the heart lumen and function to pump efficiently. A lack of trabeculation causes embryonic lethality in mice and excess trabeculation causes cardiomyopathy and heart failure in human. Its clinical relevance is exemplified by trabecular non-compaction cardiomyopathy, in which trabeculae fail to undergo compaction and about half a million Americans suffer from this disease. Despite the fundamental nature of this morphogenic process and its critical clinical implication, the cellular and molecular mechanisms that regulate trabeculation are not clear. During trabecular initiation, myocardial cells protrude into the cardiac jelly and are oriented perpendicular to the heart wall. We deleted the intracellular adaptor protein Numb and its homolog Numblike, known as Numb Family Proteins (NFP) in mouse heart to generate myocardium NFP double knockout (MDKO) and found that MDKO hearts displayed a variety of cardiac defects, including a marked disruption in the trabecular initiation and cardiomyocyte differentiation. 3-dimentional (3D) imaging indicates that cardiomyocytes in MDKO fail to protrude into the heart lumen. Using lineage tracing/mosaic mouse model, we found that the majority of the NFP null clones failed to localize to the trabeculae. Our central hypothesis is tha NFP regulate trabecular initiation and differentiation by controlling directional migration and oriented cell division (OCD) via N-cadherin (N-CAD) dependent mechanisms, which will be tested by two aims.
Aim I : Determine whether NFP regulate trabecular initiation by controlling directional migration and OCD. We will perform multicolor lineage tracing using the Brainbow mouse in which single cells in the heart tube will be genetically labeled before trabeculation, which allows us to analyze the localization of each labeled cardiomyocyte descendants and track their dynamics during trabeculation. Time-lapse 4D imaging will be applied to observe how cardiomyocytes initiate trabecula. We will identify if OCD is an asymmetric cell division and contributes to trabecular cardiomyocyte differentiation.
This aim will reveal the cellular basis fo trabecular initiation and morphogenesis.
Aim II : Determine whether NFP regulate trabeculation by stabilizing N-CAD. We will determine the functional residues/domains of Numb that are required for migration and N-CAD expression. Epistasis analysis and transgenic line rescuing will be applied to determine the genetic interaction between N-CAD and Numb.
This aim will begin to reveal molecular mechanisms of how NFP regulate trabeculation. Completion of these aims is expected to yield novel insights into the cellular and molecular mechanisms of trabecular initiation and cardiomyocyte differentiation in vivo, and the functions of NFP in these processes, which will ultimately provide a mechanistic basis for treating non-compaction cardiomyopathy and morphogenesis related congenital heart defects (CHD).

Public Health Relevance

Cardiovascular diseases are leading causes of morbidity and mortality. One such disease is non-compaction cardiomyopathy. Our work focuses on cellular and molecular mechanisms of trabecular initiation. Understanding the mechanisms underlying can lead to potential therapies for treatment of non-compaction cardiomyopathy and congenital heart defects.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL121700-04
Application #
9392922
Study Section
Cardiovascular Differentiation and Development Study Section (CDD)
Program Officer
Schramm, Charlene A
Project Start
2014-11-15
Project End
2019-10-31
Budget Start
2017-11-01
Budget End
2018-10-31
Support Year
4
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Albany Medical College
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
190592162
City
Albany
State
NY
Country
United States
Zip Code
12208
Ray, Poulomi; Chin, Amanda S; Worley, Kathryn E et al. (2018) Intrinsic cellular chirality regulates left-right symmetry breaking during cardiac looping. Proc Natl Acad Sci U S A 115:E11568-E11577
Miao, Lianjie; Li, Jingjing; Li, Jun et al. (2018) Notch signaling regulates Hey2 expression in a spatiotemporal dependent manner during cardiac morphogenesis and trabecular specification. Sci Rep 8:2678
Wu, Mingfu (2018) Mechanisms of Trabecular Formation and Specification During Cardiogenesis. Pediatr Cardiol 39:1082-1089
Zhao, Jinjing; Wu, Wen; Zhang, Wei et al. (2017) Selective expression of TSPAN2 in vascular smooth muscle is independently regulated by TGF-?1/SMAD and myocardin/serum response factor. FASEB J 31:2576-2591
Dong, Bin; Wu, Song; Wang, Jing et al. (2017) Chlamydomonas IFT25 is dispensable for flagellar assembly but required to export the BBSome from flagella. Biol Open 6:1680-1691
Li, Jingjing; Miao, Lianjie; Zhao, Chen et al. (2017) CDC42 is required for epicardial and pro-epicardial development by mediating FGF receptor trafficking to the plasma membrane. Development 144:1635-1647
Li, Jingjing; Miao, Lianjie; Shieh, David et al. (2016) Single-Cell Lineage Tracing Reveals that Oriented Cell Division Contributes to Trabecular Morphogenesis and Regional Specification. Cell Rep 15:158-170
Shaikh Qureshi, Wasay M; Miao, Lianjie; Shieh, David et al. (2016) Imaging Cleared Embryonic and Postnatal Hearts at Single-cell Resolution. J Vis Exp :
Wu, Mingfu; Li, Jingjing (2015) Numb family proteins: novel players in cardiac morphogenesis and cardiac progenitor cell differentiation. Biomol Concepts 6:137-48