Deepak Srivastava, M.D.
Director, Gladstone Institute of Cardiovascular Disease
Professor, Departments of Pediatrics and Biochemistry & Biophysics
Wilma and Adeline Pirag Distinguished Professor in Pediatric Developmental Cardiology
University of California, San Francisco
Email: dsrivastava@gladstone.ucsf.edu
Telephone: 415-734-2716
Fax: 415-355-0141
Address:
1650 Owens Street
San Francisco, CA 94158

Areas of investigation
Our laboratory focuses on understanding the causes of heart disease and on using knowledge of cardiac developmental pathways to devise novel therapeutics for human cardiac disorders. Specifically, we study the molecular events regulating early and late developmental decisions that instruct progenitor cells to adopt a cardiac cell fate and subsequently fashion a functioning heart. We seek ways to use these pathways to prevent congenital defects and treat acquired heart disease. We also seek to identify the causes of human cardiovascular disease by applying modern genetic technologies for the study of complex traits.

Significance
Heart disease is the number one killer on both sides of the age spectrum, resulting in significant mortality and morbidity in children and adults. Congenital heart disease occurs in one of every one hundred live births and results from abnormalities of early cues that guide embryonic stem cells to form the four-chambered heart. Discovery of the genetic causes and molecular mechanisms of congenital heart disease will provide potential for novel preventive and therapeutic approaches in children. We have shown that the same knowledge can be used to devise clever ways of helping the injured adult heart repair itself by using some of the tools common to younger, embryonic hearts. Finally, the molecular instructions that enable the embryo to make a heart will be useful in directing stem cells to make new heart cells—a potential treatment for heart failure or severe heart damage.

Approaches
We use many approaches to answer our research questions, including mouse and human genetics, molecular and developmental biology, and biochemistry. Transgenic mouse models are instrumental for elucidating the molecular pathways that regulate cardiac differentiation and the three-dimensional organization of the heart in vivo. To understand their contribution to disease, pathways discovered in mice and other model systems can be interrogated by mutational analysis of cells from humans with heart disease. In addition, we use traditional human genetic approaches to study families with autosomal dominant congenital heart defects to discover the genetic causes of human disease. Molecular and biochemical analyses of normal and mutated human genes, including the study of disease-specific induced pluripotent stem (iPS) cells, provide insights into the mechanisms underlying normal and abnormal cardiac developmental decisions. Finally, we use mouse models of myocardial infarctions (heart attacks) to evaluate developmental genes for their efficacy as therapeutic agents for acquired heart disease. The potential for cardiac developmental genes to reprogram stem cells into the cardiac fate will be an important approach for future studies.

Contributions
Our laboratory has elucidated a cascade of transcriptional and signaling events that control the early steps of cardiomyocyte differentiation and expansion into ventricular chambers. We found that muscle-specific histone methyltransferases and microRNAs regulate the activity of Hand2, a transcription factor essential for ventricle formation and more recently showed that microRNAs can efficiently guide stem cell fate decisions. We generated the first mouse “knockout” of a microRNA and showed that even decreasing dosage of a microRNA can have dramatic consequences on multiple aspects of cardiovascular function. We have subsequently found miRNAs that direct cardiac muscle, smooth muscle, and endothelial cells from pluripotent stem cells. In addition, we discovered a series of signaling events beginning with the morphogen Sonic hedgehog (Shh) that are essential for guiding a population of late cardiac progenitor cells in the outflow tract of the heart. These same cells form niches of cardiac progenitor cells postnatally. This pathway involves the transcription factor Tbx1, heterozygosity of which causes cardiac defects associated with DiGeorge syndrome. Finally, we used human genetics to discover the cause of some human cardiac septal defects (GATA4) and valve diseases (NOTCH1) and revealed the mechanisms through which mutations in these genes result in anomalies. As hoped, we found that a developmental gene, thymosin β4, has potent properties for cardioprotection in the setting of heart attacks in mice. We are now moving this discovery into Phase II clinical trials (FDA approved) in patients suffering ischemic damage to the heart.

Some questions addressed in ongoing studies:

• What are the direct targets of key transcription factors that regulate cardiogenesis and cardiomyocyte differentiation?
• How do mutations in human disease genes, such as TBX1, GATA4, and NOTCH1, actually cause disease and how could anomalies be prevented even in the setting of mutations?
• Do combinatorial human mutations/polymorphisms in cardiac developmental genes cause predisposition to disease?
• How do microRNAs regulate cardiogenesis and cardiac stem cells?
• Are microRNAs involved in human disease?
• How do microRNAs recognize their targets and how can one predict targets?
• How does thymosin β4, or related pathway members, protect tissues from ischemic damage?

Selected Publications:

Garg V, Kathiriya IS, Barnes R, Schluterman MK, King IN, Butler CA, Rothrock CR, Eapen RS, Hirayama-Yamada K, Joo K, Matsuoka R, Cohen JC, Srivastava D. (2003) GATA4 mutations cause human congenital heart defects and reveal an interaction with TBX5. Nature 424: 443–447.

Bock-Marquette I, Saxena A, White MD, Dimaio JM, Srivastava D. (2004) Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature 432: 466–472.

Zhao Y, Samal E, Srivastava D. (2005) Serum response factor regulates a muscle-specific mircroRNA that targets Hand2 during cardiogenesis. Nature 436:214-220.

Garg V, Muth AN, Ransom JF, Schluterman MK, Barnes R, King IN, Grossfeld PD, Srivastava D. (2005) Mutations in NOTCH1 cause aortic valve disease. Nature 437:270–274.

Srivastava D. (2006) Making or breaking the heart: From lineage determination to morphogenesis. Cell126:1037–1048.

Zhao Y, Ransom JF, Li A, Vedantham V, von Drehle M, Muth AN, Tsuchihashi T, McManus MT, Schwartz RJ, Srivastava D. (2007) Dysregulation of cardiogenesis, cardiac conduction, and cell cycle in mice lacking miRNA-1-2. Cell 129:303–317.

Ivey KN, Muth A, Arnold J, King FW, Yeh R-F, Fish JE, HSaio EC, Schwartz RJ, Conklin BR, Bernstein HS, Srivastava D. (2008) MicroRNA regulation of cell lineages in mouse and human embryonic stem cells. Cell Stem Cell 2:219-229.

Fish JE, Santoro MM, Morton SU, Yu S, Yeh RF, Wythe JD, Ivey KN, Bruneau BG, Stainier DYR, Srivastva D. (2008) miR-126 regulates angiogenic signaling and vascular integrity. Dev. Cell 15:272-284.

Ieda M, Tsuchihashi T, Ivey KN, Ross RS, Hong T-T, Shaw RM, Srivastava D. (2009) Cardiac fibroblasts regulate myocardial proliferation through beta-1 integrin signaling. Dev. Cell 16:233-244.

Cordes KR, Sheehy NT, White M, Berry E, Morton SU, Muth AN, Lee T-H, Miano JM, Ivey KN, Srivastava D. (2009) miR-145 and miR-143 regulate smooth muscle cell fate and plasticity. Nature 460:705–710.