Long non-coding RNA MALAT1 regulates cardiomyocytes apoptosis after hypoxia/reperfusion injury via modulating miR-200a-3p/PDCD4 axis

Epigenetic Signaling and RNA Regulation in Cardiovascular Diseases

RNA epigenetics is perhaps the most recent field of interest for translational epigeneticists. RNA modifications create such an extensive network of epigenetically driven combinations whose role in physiology and pathophysiology is still far from being elucidated. Not surprisingly, some of the players determining changes in RNA structure are in common with those involved in DNA and chromatin structure regulation, while other molecules seem very specific to RNA. It is envisaged, then, that new small molecules, acting selectively on RNA epigenetic changes, will be reported soon, opening new therapeutic interventions based on the correction of the RNA epigenetic landscape. In this review, we shall summarize some aspects of RNA epigenetics limited to those in which the potential clinical translatability to cardiovascular disease is emerging.

Hydrogen sulfide exposure induces apoptosis and necroptosis through lncRNA3037/miR-15a/BCL2-A20 signaling in broiler trachea

Hydrogen sulfide (H₂S) is an air pollutant, has toxic effects on respiratory tract. However, the underlying mechanisms of H₂S induced respiratory toxicity and the roles of long non-coding RNAs (lncRNA) and microRNA (miRNA) in this process remain poorly understood. To clear this, we investigated the change of tracheal tissue ultrastructure and the expression profiles of lncRNAs and miRNAs of chicken trachea exposed to H₂S for 42 days. Results showed that H₂S exposure triggered apoptosis, necroptosis, and differential expression of 16 lncRNAs and 18 miRNAs in broiler tracheas. The results of LMH cells stimulated by NaHS in vitro also showed the occurrence of apoptosis and necroptosis. LncRNA3037 is down-regulated and miR-15a is up-regulated in tracheal tissue and LMH cells under H₂S exposure. Bioinformatics analysis and dual luciferase reporter system showed lncRNA3037 bound directly to miR-15a and negatively regulates each other. A20 and BCL2 are the target genes of miR-15a and negatively regulated by it. Overexpression of miR-15a caused apoptosis and necroptosis and its inhibition partially reversed apoptosis and necroptosis of LMH cells caused by NaHS stimulation and lncRNA3037 knockdown. Taken together, we concluded that H₂S exposure mediates apoptosis and necroptosis through lncRNA3037/miR-15/A20-BCL2. These results provide new insights for unveiling the biological effects of H₂S in vivo and in vitro.

Bioinformatics Research Methodology of Non-coding RNAs in Cardiovascular Diseases

The transcriptional complexity generated by the human genomic output is within the core of cell and organ physiology, but also could be in the origin of pathologies. In cardiovascular diseases, the role of specific families of RNA transcripts belonging to the group of the non-coding RNAs started to be unveiled in the last two decades. The knowledge of the functional rules and roles of non-coding RNAs in the context of cardiovascular diseases is an important factor to derive new diagnostic methods, but also to design targeted therapeutic strategies. The characterization and analysis of ncRNA function requires a deep knowledge of the regulatory mechanism of these RNA species that often relies on intricated interaction networks. The use of specific bioinformatic tools to interrogate biological data and to derive functional implications is particularly relevant and needs to be extended to the general practice of translational researchers. This chapter briefly summarizes the bioinformatic tools and strategies that could be used for the characterization and functional analysis of non-coding RNAs, with special emphasis in their applications to the cardiovascular field.

MALAT1 is involved in the pathophysiological process of PCOS by modulating TGFβ signaling in granulosa cells

Polycystic ovary syndrome (PCOS) is an endocrine disorder, the etiology of which is complex and unclear. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a conserved long non-coding RNA which has been found to play a role in the pathophysiological process of reproductive system diseases, such as endometriosis and pregnancy loss. However, the role of MALAT1 in PCOS is still unknown. In this study, reduced MALAT1 expression was found in granulosa cells (GCs) from 68 patients with PCOS and 30 healthy controls, which relates to upregulated cell proliferation and downregulated apoptosis. Using phosphorylation pathway profiling array, MALAT1 reduction was identified to contribute to the repression of transforming growth factor beta (TGFβ) signaling in GCs. Subsequently, MALAT1 was confirmed to function as a competing endogenous RNA (ceRNA), interacting with miR-125b and miR-203a. Meanwhile, miR-125b and miR-203a was identified as two novel TGFβ signaling negative regulators by targeting TGFBR1 and TGFBR2. Finally, MALAT1 knockdown was found to induce the upregulation of miR-125b and miR-203a, which further repressed TGFβ signaling, changed some downstream gene expression, and resulted in a disordered cell cycle. In conclusion, MALAT1 reduction was identified in GCs, which may contribute to the pathophysiological processes of PCOS by regulating TGFβ signaling through sponging miR-125b and miR-203a.

The role of lncRNA MALAT1 in cardiovascular disease

Cardiovascular disease (CVD) is the first leading cause of death worldwide. Understanding the molecular mechanism of signaling pathways involved in pathology of CVD is benefit for targeted therapeutics. Recently, long non-coding RNAs (lncRNAs) are found and involved in regulation of pathology of CVD at different levels. Among them, MALAT1 attracted more attention as it was profoundly expressed in endothelial cells or cardiomyocytes in response to the risk factors of CVD, such as hypoxia, high glucose, cytokine, and oxidative stress. In this review, we summarize recent progresses in research on the molecular mechanism of MALAT1 on regulating the pathophysiological processes of CVD as well as its potential therapeutic applications.

RETRACTED: LncRNA MALAT1 knockdown alleviates oxygen-glucose deprivation and reperfusion induced cardiomyocyte apoptotic death by regulating miR-122

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. The journal was initially contacted by the corresponding author to request the retraction of the article. Given the comments of Dr Elisabeth Bik regarding this article “… the Western blot bands in all 400+ papers are all very regularly spaced and have a smooth appearance in the shape of a dumbbell or tadpole, without any of the usual smudges or stains. All bands are placed on similar looking backgrounds, suggesting they were copy/pasted from other sources, or computer generated”, the journal requested the authors to provide the raw data. However, the authors were not able to fulfil this request and therefore the Editor-in-Chief decided to retract the article.

Insight into long noncoding RNA-miRNA-mRNA axes in myocardial ischemia-reperfusion injury: the implications for mechanism and therapy

Emerging evidence has demonstrated that regulatory noncoding RNAs (ncRNAs), such as long noncoding RNAs (lncRNAs) and miRNAs, play crucial roles in the initiation and progress of myocardial ischemia-reperfusion injury (MIRI), which is associated with autophagy, apoptosis and necrosis of cardiomyocytes, as well as oxidative stress, inflammation and mitochondrial dysfunction. LncRNAs serve as a precursor or host of miRNAs and directly/indirectly affecting miRNAs via competitive binding or sponge effects. Simultaneously, miRNAs post-transcriptionally regulate the expression of genes by targeting various mRNA sequences due to their imperfect pairing with mRNAs. This review summarizes the potential regulatory role of lncRNA-miRNA-mRNA axes in MIRI and related molecular mechanisms of cardiac disorders, also provides insight into the potential therapies for MIRI-induced diseases.

miR-21 deficiency contributes to the impaired protective effects of obese rat mesenchymal stem cell-derived exosomes against spinal cord injury

The therapeutic effect of stem cell transplantation in traumatic spinal cord injury (SCI) has been extensively studied these days, and evidence has shown that stem cell-derived exosomes and exosome-shuttled miRNA (e.g. miR-21) contribute to the protective effects of stem cell transplantation against SCI. It has been reported that obesity, a prevalent metabolic disorder, reshapes stem cells and their extracellular vesicles. However, the effects of exosomes derived from obese rat stem cells on SCI and its underlying mechanism remain unknown. Here, we examined the effects of exosomes derived from obese rat mesenchymal stem cells (MSCs) on SCI, and tested the role of miR-21 in their effects. We found that exosomes derived from obese rat MSCs showed decreased miR-21 levels and did not exert protective effects against SCI. Overexpression of miR-21 in obese rat MSCs restored the protective effects of exosomes purified from obese rat MSCs against SCI. In addition, obese rat MSCs showed insulin resistance, and MSC insulin resistance decreased miR-21 levels in its secreted exosomes. These results suggested that miR-21 deficiency in obese rat MSCs contributes to the impaired protective effects of obese rat MSCs-derived exosomes against SCI, and further reinforced the notion that miR-21 is a potential molecule for treatment of SCI.

MicroRNA-200a-3p accelerates the progression of osteoporosis by targeting glutaminase to inhibit osteogenic differentiation of bone marrow mesenchymal stem cells

To uncover the role of microRNA-200a-3p in regulating osteogenic differentiation of MSCs via targeting glutaminase, thus influencing the progression of OP. Serum level of microRNA-200a-3p in OP patients and healthy controls was determined by qRT-PCR. MicroRNA-200a-3p level in MSCs undergoing osteogenic differentiation for different days was examined as well. ALP activity, calcification nodules and relative levels of Bglap, Runx2 and OPN in MSCs overexpressing microRNA-200a-3p undergoing osteogenic differentiation were detected. Relative l-glutaminase uptake in MSCs undergoing osteogenic differentiation for different days was determined. After transfection of si-GLS in MSCs undergoing osteogenic differentiation, l-glutaminase uptake, ALP activity and relative levels of Bglap, Runx2 and OPN were detected. The potential binding relationship between microRNA-200a-3p and GLS was tested by dual-luciferase reporter gene assay. Finally, rescue experiments were conducted to elucidate the role of microRNA-200a-3p/GLS in osteogenic differentiation of MSCs. MicroRNA-200a-3p level was higher in serum of OP patients relative to controls. Its level in MSCs gradually decreased with the prolongation of osteogenic differentiation. Overexpression of microRNA-200a-3p reduced cell viability, ALP activity, number and volume of calcification nodule. The mRNA levels of Bglap, Runx2 and OPN were downregulated by overexpressed microRNA-200a-3p. The cell viability, ALP activity, number and volume of calcification nodule were reduced when microRNA-200a-3p was knocked down. The mRNA levels of Bglap, Runx2 and OPN were upregulated when transfected microRNA-200a-3p inhibitor. l-glutaminase uptake increased with the prolongation of osteogenic differentiation in MSCs. Knockdown of GLS attenuated l-glutaminase uptake and ALP activity, as well as downregulated Bglap, Runx2 and OPN. Besides, GLS was verified to directly bind to microRNA-200a-3p. GLS overexpression reversed the inhibitory effects of overexpressed microRNA-200a-3p on osteogenic differentiation of MSCs. MicroRNA-200a-3p suppresses osteogenic differentiation of MSCs via targeting glutaminase, thereafter accelerating the progression of OP.