Long Noncoding RNAs Involved in Cardiomyocyte Apoptosis Triggered by Different Stressors

Crucial role of lncRNA NONHSAG037054.2 and GABPA, and their related functional networks, in ankylosing spondylitis

Long non-coding RNAs (lncRNAs) have been previously researched in ankylosing spondylitis (AS). Nevertheless, there are few studies of lncRNAs and mRNAs associated with the pathogenesis of AS. Differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) between AS and normal samples were assessed using the R limma package. DOSE packages and 'clusterProfiler' were exploited for gene enrichment analysis. The functional association of proteins and protein interactions was assessed using the STRING database. To investigate the important genes and subnetworks in the protein-protein interaction network, the MCODE plug-in in the Cytoscape software was utilized. The gene mRNA was examined via reverse transcription-quantitative PCR. In total, 152 DEmRNAs and 204 DElncRNAs were observed between normal and AS samples. A total of 68 candidate genes related to DElncRNA were identified. These candidate genes were enriched in 30 cellular component terms, 22 molecular functions, 83 biological processes, 9 Kyoto Encyclopedia of Genes and Genomes, and 36 disease ontology pathways. NONHSAG037054.2 was the most related lncRNA to genes, and GABPA was the most connected gene to lncRNA in AS. The NCBI/GenBank accession number of the lncRNA NONHSAG037054.2 was not found because it is not included in NCBI. The information of lncRNA NONHSAG037054.2 can be found at the website (http://www.noncode.org/show_gene.php?id=NONHSAG037054 and https://www.genecards.org/cgi-bin/carddisp.pl?gene=ACAP2-IT1). In total, 13 microRNAs (miRNAs) and 46 miRNAs associated with NONHSAG037054.2 and GABPA, respectively, were found. A total of 173 RNA-binding protein genes were associated with both NONHSAG037054.2 and GABPA. In addition, GABPA was downregulated in AS samples, suggesting it may have diagnostic value in AS. In conclusion, NONHSAG037054.2 and GABPA are associated with AS. GABPA was downregulated in AS, and it could serve as a novel diagnostic factor for AS.

LINC01013 Is a Determinant of Fibroblast Activation and Encodes a Novel Fibroblast-Activating Micropeptide

Myocardial fibrosis confers an almost threefold mortality risk in heart disease. There are no prognostic therapies and novel therapeutic targets are needed. Many thousands of unannotated small open reading frames (smORFs) have been identified across the genome with potential to produce micropeptides (< 100 amino acids). We sought to investigate the role of smORFs in myocardial fibroblast activation.Analysis of human cardiac atrial fibroblasts (HCFs) stimulated with profibrotic TGFβ1 using RNA sequencing (RNA-Seq) and ribosome profiling (Ribo-Seq) identified long intergenic non-coding RNA LINC01013 as TGFβ1 responsive and containing an actively translated smORF. Knockdown of LINC01013 using siRNA reduced expression of profibrotic markers at baseline and blunted their response to TGFβ1. In contrast, overexpression of a codon-optimised smORF invoked a profibrotic response comparable to that seen with TGFβ1 treatment, whilst FLAG-tagged peptide associated with the mitochondria.Together, these data support a novel LINC01013 smORF micropeptide-mediated mechanism of fibroblast activation. TGFβ1 stimulation of atrial fibroblasts induces expression of LINC01013, whose knockdown reduces fibroblast activation. Overexpression of a smORF contained within LINC01013 localises to mitochondria and activates fibroblasts.