miR-322/-503 cluster is expressed in the earliest cardiac progenitor cells and drives cardiomyocyte specification

Abstract

Understanding the mechanisms of early cardiac fate determination may lead to better approaches in promoting heart regeneration. We used a mesoderm posterior 1 (Mesp1)-Cre/Rosa26-EYFP reporter system to identify microRNAs (miRNAs) enriched in early cardiac progenitor cells. Most of these miRNA genes bear MESP1-binding sites and active histone signatures. In a calcium transient-based screening assay, we identified miRNAs that may promote the cardiomyocyte program. An X-chromosome miRNA cluster, miR-322/-503, is the most enriched in the Mesp1 lineage and is the most potent in the screening assay. It is specifically expressed in the looping heart. Ectopic miR-322/-503 mimicking the endogenous temporal patterns specifically drives a cardiomyocyte program while inhibiting neural lineages, likely by targeting the RNA-binding protein CUG-binding protein Elav-like family member 1 (Celf1). Thus, early miRNAs in lineage-committed cells may play powerful roles in cell-fate determination by cross-suppressing other lineages. miRNAs identified in this study, especially miR-322/-503, are potent regulators of early cardiac fate.

Endoplasmic reticulum and the microRNA environment in the cardiovascular system

“…This cleavage may lead to premature degradation of this microRNA, correlating with activation of IRE1α, and a significant decrease in miR-322 upon thapsigargin treatment that activates IRE1α. The miR-322/503 family is upregulated during early stages of cardiogenesis (Shen et al 2016), while activation of IRE1α is linked to human heart failure and ischemia/reperfusion damage (Szegezdi et al 2006;Thuerauf et al 2006). Silencing of IRE1α in mouse fibroblasts resulted in significant increase in abundance of miR-322, indicating a role for IRE1α in the degradation of miR-322 ( Fig.…”

“…miR-499 is also strongly associated with cardiac differentiation of human ES cells (Fu et al 2011;Wilson et al 2010). One of the earliest families of microRNAs that is increased in abundance during cardiomyocyte differentiation is the miR-322/503 cluster, located on the X chromosome (Shen et al 2016). This family of microRNAs targets Celf1 (Le Tonqueze et al 2016), reducing expression of a protein that is involved in the differentiation of neuroectoderm and inhibition of cardiac differentiation.…”

“…Using the IPA platform, mmu-miR-322 gene targets were separated into several canonical pathways, including seven genes involved in tight junction signaling (4.3%), five genes involved in TGFβ signaling (5.6%), and six genes involved in WNT/β-catenin signaling (3.5%) (Table 2). As miR-322 is one of the earliest microRNA families expressed during cardiac differentiation, it may play a role in the regulation of the WNT pathway (Shen et al 2016). The WNT signaling pathway performs a central role in cardiac myocyte differentiation during the early stages of development and is tightly controlled during differentiation (Tian et al 2010).…”

“…miR-322 is located on the reverse strand of the X-chromosome at site 50,407,432 -50,407,526 (Pinheiro et al 2011), in close proximity to miR-503, suggesting that both microRNAs may be regulated in a similar manner. Both miR-322 and miR-503 are associated with cardiac development (Shen et al 2016), and deep sequencing analysis indicated that miR-503 was downregulated to a similar extent as miR-322 (Table 1). Some of the putative targets of miR-322 that we have identified include Smad3 and PPIγ (Fig.…”

Cardiac Progenitor Cells from Stem Cells: Learning from Genetics and Biomaterials

“…Additionally, Xiao et al (2012) revealed that inhibition of miR-204 suppressed CPC differentiation and promoted proliferation without affecting cell viability [218]. A study in 2016 identified several microRNAs that regulate cardiac fate, like let-7, miR-18, miR-302 and the miR-17-92 cluster, in MESP1 + CPCs [220]. It was also shown that the CPCs were particularly enriched for the miR-322/-503 cluster which targets the CUG-binding protein Elav-like family member 1 (CELF1).…”