Genetic mutations that cause congenital heart malformations are often heterozygous and involve a partial reduction in protein dosage or an increase in protein activity. Although developmental events are precisely controlled by signaling pathways and transcriptional networks, our studies have revealed an intertwined layer of post-transcriptional regulation that involves microRNAs (miRNAs) that titrate protein dosage. The muscle-specific miRNA miR-1 is co-transcribed with a second miRNA, miR-133, and participates in septal formation, cell-cycle regulation, cardiac conduction, and other aspects of cardiac development and homeostasis. miR-1 and miR-133 are encoded in two loci as a result of a gene duplication, with identical mature sequences of miR-1-1 and miR-1-2, as well as miR-133a and miR- 133b. Loss of two redundant copies of miR-133 results in a ventricular septal defect, similar to deletion of miR-1-2. miR-1 and miR-133 appear to function in concert in some biological settings, but have opposing functions in others. The function of miR-1 is dose sensitive, as shown by gene targeting of miR-1-2, although the full function of miR-1 awaits compound deletion of miR-1-2 and its redundant allele, miR-1-1. Several targets of miR-1 are known, including Hand2, Irx5 and Delta-like 1. However, the contribution of individual targets to miR-1's function in vivo is unknown, and most targets of miR-1 and miR-133 are also unknown. We hypothesize that miR-1 is required for cardiac progenitor development in vivo and for postnatal cardiac function and that a discrete set of mRNA targets play major roles in mediating miR-1's function. We also hypothesize that miR-1 and miR-133 converge on common targets to cooperatively regulate cellular decisions but have other targets that mediate distinct functions. To test these hypotheses, we propose three specific aims:
Aim 1) To determine the dose- dependent requirement of miR-1 in cardiac development and in post-natal cardiac function by analyzing compound deletions of miR-1-1 and miR-1-2;
Aim 2) To determine whether repression of individual miR-1 targets mediates major functions of miR-1 in vivo;
and Aim 3) To determine whether miR-1 and miR-133 share common targets upon which they can cooperate or synergize and whether they have distinct targets that mediate opposing functions. These studies will utilize several innovative approaches and will reveal miRNA and transcriptional networks that titrate protein dosage to control critical events in cardiogenesis.
Quantitative disruption of the molecular networks regulating cardiac development underlies many forms of congenital heart disease. In this proposal, we integrate the precise control of protein dosage through small RNAs, known as microRNAs, with other known regulators of cardiogenesis to understand the multiple levels by which heart formation is controlled.
|King, Isabelle N; Yartseva, Valeria; Salas, Donaldo et al. (2014) The RNA-binding protein TDP-43 selectively disrupts microRNA-1/206 incorporation into the RNA-induced silencing complex. J Biol Chem 289:14263-71|
|Ang, Yen-Sin; Srivastava, Deepak (2014) Oxygen: double-edged sword in cardiac function and repair. Circ Res 115:824-5|
|Srivastava, Deepak; Heidersbach, Amy J (2013) Small solutions to big problems: microRNAs for cardiac regeneration. Circ Res 112:1412-4|
|Srivastava, Deepak; Berry, Emily C (2013) Cardiac reprogramming: from mouse toward man. Curr Opin Genet Dev 23:574-8|
|Cheng, Paul; Andersen, Peter; Hassel, David et al. (2013) Fibronectin mediates mesendodermal cell fate decisions. Development 140:2587-96|
|Srivastava, Deepak; Cordes Metzler, Kimberly R (2013) Fending for a Braveheart. EMBO J 32:1211-3|
|Yu, Sangho; Crawford, Dianna; Tsuchihashi, Takatoshi et al. (2011) The chemokine receptor CXCR7 functions to regulate cardiac valve remodeling. Dev Dyn 240:384-93|
|King, Isabelle N; Qian, Li; Liang, Jianping et al. (2011) A genome-wide screen reveals a role for microRNA-1 in modulating cardiac cell polarity. Dev Cell 20:497-510|
|Tsuchihashi, Takatoshi; Maeda, Jun; Shin, Chong H et al. (2011) Hand2 function in second heart field progenitors is essential for cardiogenesis. Dev Biol 351:62-9|
|van Laake, Linda W; Qian, Li; Cheng, Paul et al. (2010) Reporter-based isolation of induced pluripotent stem cell- and embryonic stem cell-derived cardiac progenitors reveals limited gene expression variance. Circ Res 107:340-7|
Showing the most recent 10 out of 32 publications