RESUMO
Circular RNAs (circRNAs) sequester microRNAs (miRNAs) and repress their endogenous activity. We hypothesized that artificial circRNA sponges (circmiRs) can be constructed to target miRNAs therapeutically, with a low dosage requirement and extended half-lives compared to current alternatives. This could present a new treatment approach for critical global pathologies, including cardiovascular disease. Here, we constructed a circmiR sponge to target known cardiac pro-hypertrophic miR-132 and -212. Expressed circmiRs competitively inhibited miR-132 and -212 activity in luciferase rescue assays and showed greater stability than linear sponges. A design containing 12 bulged binding sites with 12 nucleotides spacing was determined to be optimal. Adeno-associated viruses (AAVs) were used to deliver circmiRs to cardiomyocytes in vivo in a transverse aortic constriction (TAC) mouse model of cardiac disease. Hypertrophic disease characteristics were attenuated, and cardiac function was preserved in treated mice, demonstrating the potential of circmiRs as novel therapeutic tools. Subsequently, group I permutated intron-exon sequences were used to directly synthesize exogenous circmiRs, which showed greater in vitro efficacy than the current gold standard antagomiRs in inhibiting miRNA function. Engineered circRNAs thus offer exciting potential as future therapeutics.
Assuntos
Cardiomegalia/fisiopatologia , Regulação da Expressão Gênica , MicroRNAs/genética , Interferência de RNA , RNA Circular/genética , Animais , Sequência de Bases , Sítios de Ligação , Cardiomegalia/diagnóstico , Cardiomegalia/etiologia , Cardiomegalia/terapia , Modelos Animais de Doenças , Técnicas de Transferência de Genes , Engenharia Genética , Terapia Genética/métodos , Vetores Genéticos/administração & dosagem , Vetores Genéticos/genética , Testes de Função Cardíaca , Camundongos , MicroRNAs/administração & dosagem , MicroRNAs/química , Estabilidade de RNA , RNA Circular/administração & dosagem , RNA Circular/químicaRESUMO
The combination of next-generation sequencing, advanced bioinformatics analysis, and molecular research has now established circular RNAs (circRNAs) as a heterogeneous group of non-coding RNA that is widely and abundantly expressed. CircRNAs are single-stranded RNA, covalently backspliced to form closed circular loops. Different models of back-splicing have been proposed, and mechanisms for circRNA function include sequestering microRNAs, direct interaction with proteins, regulation of transcription, and translation. Exploring the role of circRNAs in different disease settings, and understanding how they contribute to disease progression promises to provide valuable insight into potential novel therapeutic approaches. Here, we review the growing number of published research on circRNAs in the heart and cardiovascular system and summarize the circRNAs that have been implicated in disease.