Abstract:Protein-coding genes account for only a small part of the human genome; in fact, the vast majority of transcripts are comprised of non-coding RNAs (ncRNAs) including long ncRNAs (lncRNAs) and small ncRNAs, microRNAs (miRs). Accumulating evidence indicates that ncRNAs could play critical roles in regulating many cellular processes which are often implicated in health and disease. For example, ncRNAs are aberrantly expressed in cancers, heart diseases, and many other diseases. LncRNAs and miRs are therefore novel and promising targets to be developed into biomarkers for diagnosis and prognosis as well as treatment options. The interaction between lncRNAs and miRs as well as its pathophysiological significance have recently been reported. Mechanistically, it is believed that lncRNAs exert "sponge-like" effects on various miRs, which subsequently inhibits miR-mediated functions. This crosstalk between two types of ncRNAs frequently contributes to the pathogenesis of the disease. In this review, we provide a summary of the recent studies highlighting the interaction between these ncRNAs and the effects of this interaction on disease pathogenesis and regulation.

These findings reveal a pivotal role for miR-150 as a regulator of cardiomyocyte survival during cardiac injury.

Cardiovascular disease is the leading cause of death in the United States, accounting for nearly one in every seven deaths. Over the last decade, various targeted therapeutics have been introduced, but there has been no corresponding improvement in patient survival. Since the mortality rate of cardiovascular disease has not been significantly decreased, efforts have been made to understand the link between heart disease and novel therapeutic targets such as non-coding RNAs. Among multiple non-coding RNAs, long non-coding RNA (lncRNA) has emerged as a novel therapeutic in cardiovascular medicine. LncRNAs are endogenous RNAs that contain over 200 nucleotides and regulate gene expression. Recent studies suggest critical roles of lncRNAs in modulating the initiation and progression of cardiovascular diseases. For example, aberrant lncRNA expression has been associated with the pathogenesis of ischemic heart failure. In this article, we present a synopsis of recent discoveries that link the roles and molecular interactions of lncRNAs to cardiovascular diseases. Moreover, we describe the prevalence of circulating lncRNAs and assess their potential utilities as biomarkers for diagnosis and prognosis of heart disease.

Rationale: MicroRNAs (miRs) are small, non-coding RNAs that function to post-transcriptionally regulate gene expression. First transcribed as long primary miR transcripts (pri-miRs), they are enzymatically processed in the nucleus by Drosha into hairpin intermediate miRs (pre-miRs) and further processed in the cytoplasm by Dicer into mature miRs where they regulate cellular processes following activation by a variety of signals such as those stimulated by β-adrenergic receptors (βARs). Initially discovered to desensitize βAR signaling, β-arrestins are now appreciated to transduce multiple effector pathways independent of G protein-mediated second messenger accumulation, a concept known as biased signaling. We previously showed that the β-arrestin-biased βAR agonist carvedilol activates cellular pathways in the heart. Objective: Here, we tested whether carvedilol could activate β-arrestin-mediated miR maturation, thereby providing a novel potential mechanism for its cardioprotective effects. Methods and Results: In human cells and mouse hearts, carvedilol upregulates a subset of mature and pre-miRs but not their pri-miRs in β1AR-, G protein-coupled receptor kinase 5/6- and β-arrestin1-dependent manner. Mechanistically, β-arrestin1 regulates miR processing by forming a nuclear complex with hnRNPA1 and Drosha on pri-miRs. Conclusions: Our findings indicate a novel function for β1AR-mediated β-arrestin1 signaling activated by carvedilol in miR biogenesis, which may be linked, in part, to its mechanism for cell survival.