MiR-182 alleviates the development of cyanotic congenital heart disease by suppressing HES1

Role of miRNA in Cardiovascular Diseases in Children-Systematic Review

The number of children suffering from cardiovascular diseases (CVDs) is rising globally. Therefore, there is an urgent need to acquire a better understanding of the genetic factors and molecular mechanisms related to the pathogenesis of CVDs in order to develop new prevention and treatment strategies for the future. MicroRNAs (miRNAs) constitute a class of small non-coding RNA fragments that range from 17 to 25 nucleotides in length and play an essential role in regulating gene expression, controlling an abundance of biological aspects of cell life, such as proliferation, differentiation, and apoptosis, thus affecting immune response, stem cell growth, ageing and haematopoiesis. In recent years, the concept of miRNAs as diagnostic markers allowing discrimination between healthy individuals and those affected by CVDs entered the purview of academic debate. In this review, we aimed to systematise available information regarding miRNAs associated with arrhythmias, cardiomyopathies, myocarditis and congenital heart diseases in children. We focused on the targeted genes and metabolic pathways influenced by those particular miRNAs, and finally, tried to determine the future of miRNAs as novel biomarkers of CVD.

Posttranscriptional Regulation by Proteins and Noncoding RNAs

Posttranscriptional regulation comprises those mechanisms occurring after the initial copy of the DNA sequence is transcribed into an intermediate RNA molecule (i.e., messenger RNA) until such a molecule is used as a template to generate a protein. A subset of these posttranscriptional regulatory mechanisms essentially are destined to process the immature mRNA toward its mature form, conferring the adequate mRNA stability, providing the means for pertinent introns excision, and controlling mRNA turnover rate and quality control check. An additional layer of complexity is added in certain cases, since discrete nucleotide modifications in the mature RNA molecule are added by RNA editing, a process that provides large mature mRNA diversity. Moreover, a number of posttranscriptional regulatory mechanisms occur in a cell- and tissue-specific manner, such as alternative splicing and noncoding RNA-mediated regulation. In this chapter, we will briefly summarize current state-of-the-art knowledge of general posttranscriptional mechanisms, while major emphases will be devoted to those tissue-specific posttranscriptional modifications that impact on cardiac development and congenital heart disease.

Effect of miR-182-5p on apoptosis in myocardial infarction

Objective

This study aimed to delineate the diagnostic significance of miR-182-5p by investigating its influence on myocardial apoptosis and function, employing both in vivo and in vitro myocardial infarction models.

Methods

A rat myocardial infarction model was established. Myocardial infarction area was detected using the 2,3,5-chlorotriphenyltetrazolium (TTC) method, myocardial enzyme spectrums were measured using enzyme-linked immunosorbent assay (ELISA), myocardial structure was detected by hematoxylin and eosin (HE) staining, myocardial apoptosis was detected using the TUNEL method, and expression levels of miR-182-5p and apoptosis-related molecules were detected using real-time fluorescence quantitative PCR (qPCR) and Western blot. miR-182-5p mimics and inhibitor were transfected into rat H9C2 cardiomyocytes and mouse HL-1 cardiomyocytes to establish a hypoxia model. Cardiomyocyte viability was detected using the CCK-8 method, expression levels of apoptosis-related indicators were detected using Western blot, and caspase-3/7 activity was detected using a caspase-3/7 activity detection kit. AAV9 adeno-associated virus was used to construct an miR-182-5p overexpression virus, which was injected into mice through the tail vein to create a mouse myocardial infarction model. TTC, ELISA, HE staining, echocardiography, real-time fluorescence qPCR, and Western blot methods were used to detect the effects of AAV9-miR-182-5p on myocardial injury, myocardial function, and myocardial apoptosis levels in myocardial infarction.

Results

The rat model displayed reduced miR-182-5p expression concurrent with an increase in apoptosis. The in vitro H9C2 and HL-1 hypoxia models revealed that miR-182-5p augmented the hypoxia-induced decrease in myocardial cell viability, suppressed Bcl-2 expression, and increased Bax, Bnip3, and caspase-3/7 activity levels. The injection of AAV9-miR-182-5p significantly exacerbated myocardial tissue damage, impaired myocardial function, and enhanced apoptosis.

Conclusion

miR-182-5p escalates myocardial injury during myocardial infarction by fostering apoptosis. Interventions that aim to reduce miR-182-5p levels might be crucial in halting the progression of myocardial infarction.

MicroRNA delivery based on nanoparticles of cardiovascular diseases

Cardiovascular disease, especially myocardial infarction, is a serious threat to human health. Many drugs currently used cannot achieve the desired therapeutic effect due to the lack of selectivity. With the in-depth understanding of the role of microRNA (miRNA) in cardiovascular disease and the wide application of nanotechnology, loading drugs into nanoparticles with the help of nano-delivery system may have a better effect in the treatment of cardiomyopathy. In this review, we highlight the latest research on miRNAs in the treatment of cardiovascular disease in recent years and discuss the possibilities and challenges of using miRNA to treat cardiomyopathy. Secondly, we discuss the delivery of miRNA through different nano-carriers, especially inorganic, polymer and liposome nano-carriers. The preparation of miRNA nano-drugs by encapsulating miRNA in these nano-materials will provide a new treatment option. In addition, the research status of miRNA in the treatment of cardiomyopathy based on nano-carriers is summarized. The use of this delivery tool cannot only realize therapeutic potential, but also greatly improve drug targeting and reduce side effects.

Role of miR-182 in cardiovascular and cerebrovascular diseases

The treatment of cardiovascular and cerebrovascular diseases have undergone major advances in recent decades, allowing for a more effective prevention of cardiovascular and cerebrovascular events. However, cardiac and cerebral atherothrombotic complications still account for substantial morbidity and mortality worldwide. Novel therapeutic strategies are critical to improve patient outcomes following cardiovascular diseases. miRNAs are small non-coding RNAs, that regulate gene expression. Here, we discuss the role of miR-182 in regulating myocardial proliferation, migration, hypoxia, ischemia, apoptosis and hypertrophy in atherosclerosis, CAD, MI, I/R injury, organ transplant, cardiac hypertrophy, hypertension, heart failure, congenital heart disease and cardiotoxicity. Besides, we also summarize the current progress of miR-182 therapeutics in clinical development and discuss challenges that will need to be overcome to enter the clinic for patients with cardiac disease.

Identification of differential microRNAs and messenger RNAs resulting from ASXL transcriptional regulator 3 knockdown during during heart development

Congenital heart disease (CHD) is the most common birth defect. Although ASXL transcriptional regulator 3 (ASXL3) has been reported to cause hereditary CHD, ASXL3-mediated mechanisms in heart development remain unclear. In this study, we used dimethyl sulfoxide (DMSO) to induce differentiation in P19 cells, observed cell morphology using light microscopy after ASXL3 knockdown, and determined the levels of associated myocardial cell markers using reverse transcription-quantitative polymerase chain reaction and western blotting. Subsequently, we used microRNA sequencing, messenger RNA (mRNA) sequencing, and bioinformatics to initially identify the possible mechanisms through which ASXL3-related microRNAs and mRNAs affect heart development. The results indicated that DMSO induced P19 cell differentiation, which could be inhibited by ASXL3 knockdown. We screened 1214 and 1652 differentially expressed microRNAs and mRNAs, respectively, through ASXL3 knockdown and sequencing; these differentially expressed miRNAs were largely enriched in PI3K-Akt, mitogen-activated protein kinase, and Rap1 signaling pathways. Additionally, 11 miRNAs associated with heart development were selected through a literature review. Our analysis indicated the involvement of mmu-miR-323-3p in P19 cell differentiation through the PI3K-Akt pathway. In conclusion, ASXL3 may be involved in the regulation of heart development. This comprehensive study of differentially expressed microRNAs and mRNAs through ASXL3 knockdown in P19 cells provides new insights that may aid the prevention and treatment of CHD.

LINC00473 exacerbates osteoarthritis development by promoting chondrocyte apoptosis and proinflammatory cytokine production through the miR-424-5p/LY6E axis

Osteoarthritis (OA) is a common degenerative joint disease that has been identified as one of the major health burdens in aging individuals. Long non-coding RNAs (lncRNAs) participate in the development of diverse diseases, including OA. Among them, lncRNA long intergenic non-protein coding RNA 473 (LINC00473) is one of the few upregulated lncRNAs. The present study aimed to explore the role of LINC00473 and its regulatory mechanism in OA development. Flow cytometry analyses and ELISA were carried out to detect chondrocyte apoptosis and the concentration of proinflammatory cytokines, respectively. The results suggested that LINC00473 knockdown significantly reduced chondrocyte apoptosis and the production of proinflammatory cytokines in IL-1β-stimulated C28/I2 cells compared with transfection with small interfering RNA-negative control (si-NC). Western blot analyses were performed to examine protein levels of apoptotic markers (caspase-3, Bax and Bcl-2) in C28/I2 cells. Subsequently, an OA rat model was established to explore the role of LINC00473 in vivo. The results indicated that, compared with the OA + adeno-associated virus si-NC group, LINC00473 knockdown significantly suppressed the degradation of chondrocyte extracellular matrix and the production of proinflammatory cytokines in OA model rats. Furthermore, bioinformatics analysis, luciferase reporter and RNA immunoprecipitation assays indicated that LINC00473 served as a microRNA (miR)-424-5p sponge in C28/I2 cells, and that lymphocyte antigen 6 locus E (LY6E) was the downstream target. In addition, the inhibitory effects of LINC00473 knockdown on chondrocyte apoptosis and the inflammatory response could be reversed by LY6E overexpression in IL-1β-stimulated C28/I2 cells. In summary, the findings indicated that LINC00473 contributed to OA progression by modulating the miR-424-5p/LY6E axis, which may serve as a potential therapeutic strategy for patients with OA.

Circ_0068087 Silencing Ameliorates Oxidized Low-Density Lipoprotein-Induced Dysfunction in Vascular Endothelial Cells Depending on miR-186-5p-Mediated Regulation of Roundabout Guidance Receptor 1

Background: Circular RNAs (circRNAs) are endogenous non-coding RNAs involved in the progression of atherosclerosis (AS). We investigated the role of circ_0068087 in AS progression and its associated mechanism.

Methods: The 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay, flow cytometry, and enzyme-linked immunosorbent assay (ELISA) were performed to analyze the viability, apoptosis, and inflammatory response of HUVECs, respectively. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and the Western blot assay were performed to measure the expression of RNA and protein. Cell oxidative stress was analyzed using commercial kits. The dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were conducted to verify the interaction between microRNA-186-5p (miR-186-5p) and circ_0068087 or roundabout guidance receptor 1 (ROBO1).

Results: Oxidized low-density lipoprotein (ox-LDL) exposure upregulated the circ_0068087 level in HUVECs. ox-LDL-induced dysfunction in HUVECs was largely attenuated by the silence of circ_0068087. Circ_0068087 negatively regulated the miR-186-5p level by interacting with it in HUVECs. Circ_0068087 knockdown restrained ox-LDL-induced injury in HUVECs partly by upregulating miR-186-5p. ROBO1 was a downstream target of miR-186-5p in HUVECs. Circ_0068087 positively regulated ROBO1 expression by sponging miR-186-5p in HUVECs. MiR-186-5p overexpression exerted a protective role in ox-LDL-induced HUVECs partly by downregulating ROBO1.

Conclusion: Circ_0068087 interference alleviated ox-LDL-induced dysfunction in HUVECs partly by reducing ROBO1 expression via upregulating miR-186-5p.

Knockdown of Long Noncoding RNA SNHG14 Protects H9c2 Cells Against Hypoxia-induced Injury by Modulating miR-25-3p/KLF4 Axis in Vitro

ABSTRACT

Cyanotic congenital heart disease (CCHD) is the main cause of death in infants worldwide. Long noncoding RNAs (lncRNAs) have been pointed to exert crucial roles in development of CHD. The current research is designed to illuminate the impact and potential mechanism of lncRNA SNHG14 in CCHD in vitro. The embryonic rat ventricular myocardial cells (H9c2 cells) were exposed to hypoxia to establish the model of CCHD in vitro. Quantitative real-time polymerase chain reaction was conducted to examine relative expressions of SNHG14, miR-25-3p, and KLF4. Cell viability was determined by the MTT assay. Lactate dehydrogenase (LDH) was measured by an LDH assay kit. Apoptosis-related proteins (Bax and Bcl-2) and KLF4 were detected by Western Blot. The targets of SNHG14 and miR-25-3p were verified by the dual-luciferase reporter assay. SNHG14 and KLF4 were upregulated, whereas miR-25-3p was downregulated in hypoxia-induced H9c2 cells and cardiac tissues of patients with CCHD compared with their controls. Knockdown of SNHG14 or overexpression of miR-25-3p facilitated cell viability, while depressing cell apoptosis and release of LDH in hypoxia-induced H9c2 cells. MiR-25-3p was a target of SNHG14 and inversely modulated by SNHG14. MiR-25-3p could directly target KLF4 and negatively regulate expression of KLF4. Repression of miR-25-3p or overexpression of KLF4 reversed the suppression impacts of sh-SNHG14 on cell apoptosis and release of LDH as well as the promotion impact of sh-SNHG14 on cell viability in hypoxia-induced H9c2 cells. Sh-SNHG14 protected H9c2 cells against hypoxia-induced injury by modulating miR-25-3p/KLF4 axis in vitro.

A Non-coding HES1 Variant Predisposes Children to Congenital Heart Disease in Chinese Population

Background: As a key component in the NOTCH signaling pathway, HES1 plays an important role in vertebrate heart development. Variants in the HES1 coding sequence are known to be associated with congenital heart disease (CHD). However, little is known about HES1 non-coding sequence variants and their association with the risk of developing CHD. Method and Results: We initially analyzed the non-coding sequence of the HES1 gene in 12 unrelated CHD families by direct sequencing and identified a previously unreported promoter region variant (NM_005524.4: c.-1279-1278 insAC, rs148941464) in the HES1 gene in four CHD families. The homozygous variant in patients was inherited from carrier parents with normal phenotypes, indicating a likely recessive genetic model. Given that the HES1 gene is predicted to be likely to exhibit haploinsufficiency (%HI: 11.44), we hypothesized that the HES1 homozygous variant is a genetic risk factor underlying CHD. We then carried out sequencing of this HES1 variant in 629 sporadic non-syndromic CHD cases and 696 healthy controls and performed association analysis. Interestingly, we observed a significant association of the homozygous HES1 promoter variant with CHD (18.92% of cases vs. 9.91% of controls; OR: 2.291, 95% CI: 1.637-3.207, p = 9.72 × 10^-7). No significant association with CHD was observed for the HES1 promoter heterozygous variant (p > 0.05). However, association analysis tests of the HES1 homozygous variant with each subtype of CHD revealed that this homozygous variant was strongly associated with transposition of the great arteries (TGA) (OR: 3.726, 95% CI: 1.745-7.956, p = 0.0003). Moreover, the prevalence of HES1 homozygous variants in CHD patients with TGA (27.66%) was significantly higher than that in patients with other CHD subtypes or controls. Similar results were observed in a replication group of TGA (n = 64). Functional studies demonstrated that the homozygous variant in the HES1 promoter can disrupt its ability to bind RXRA, an inhibitory transcription factor, which results in abnormally high expression of the HES1 gene, indicating that this variant harbors gain-of-function effects. Conclusions: Our findings reveal that the non-coding homozygous variant in the HES1 promoter has a gain-of-function effect and is associated with an increased risk of CHD development, especially the severe TGA subtype.

MicroRNA-219-5p participates in cyanotic congenital heart disease progression by regulating cardiomyocyte apoptosis

MicroRNAs (miRs) play important roles in the protection against and development of congenital heart disease (CHD). However, the role and potential mechanisms of miR-219-5p in cyanotic CHD remains unclear. Reverse transcription-quantitative PCR (RT-qPCR) was used to measure miR-219-5p levels in cyanotic CHD and hypoxia-induced H9C2 cells. Dual luciferase reporter gene assay was used to confirm whether liver receptor homolog-1 (LRH-1) was a direct target of miR-219-5p. miR-219-5p inhibitor and LRH-1-small interfering RNA were transfected into H9C2 cells under hypoxic conditions to investigate the role of miR-219-5p in hypoxia-induced H9C2 cells. Subsequently, cell viability was detected using an MTT assay and cell apoptosis was detected using flow cytometry. In addition, RT-qPCR and western blotting assays were performed to detect the mRNA and protein expression of LRH-1, cyclin D1 and β-catenin, respectively. The data showed that miR-219-5p expression was higher in patients with cyanotic CHD compared with patients with acyanotic CHD gradually increased in H9C2 cells with prolonged hypoxia time. Dual luciferase reporter assay results showed that LRH-1 was a direct target gene of miR-219-5p. Inhibition of miR-219-5p reversed hypoxia-induced cell viability reduction and attenuated hypoxia-induced cell apoptosis. In addition, hypoxia induction inhibited the expression of LRH-1, cyclin D1 and β-catenin, which was reversed by miR-219-5p inhibitor. However, LRH-1 downregulation reversed the miR-219-5p inhibitor enhanced cell viability, decreased cell apoptosis and increased expression of LRH-1, cyclin D1 and β-catenin in hypoxia-treated cardiomyocytes. The present results demonstrated that downregulation of miR-219-5p promoted the expression of the LRH-1/Wnt/β-catenin signaling pathway-associated components, reduced cardiomyocyte apoptosis and increased cell growth under hypoxic conditions. miR-219-5p may be a potential therapeutic target for cyanotic CHD therapy.

miR-375-3p contributes to hypoxia-induced apoptosis by targeting forkhead box P1 (FOXP1) and Bcl2 like protein 2 (Bcl2l2) in rat cardiomyocyte h9c2 cells

miRNAs have been pointed to play critical role in the development of congenital heart disease (CHD). miRNA-375-3p (miR-375-3p) was involved in cardiac dysfunction and cardiogenesis. However, no prior study had established a therapeutic role of miR-375-3p in CHD. We intended to investigate the effect and mechanism of miR-375-3p on apoptosis in hypoxic cardiomyocytes in vitro. Expression of miR-375-3p, forkhead box P1 (FOXP1) and Bcl2 like protein 2 (Bcl2l2) was detected using real-time quantitative PCR and western blot. Apoptosis was measured with MTT assay, flow cytometry and caspase-3 activity assay. The potential target binding between miR-375-3p and FOXP1/Bcl2l2 was predicted on DianaTools, and was validated by luciferase reporter assay and RNA pull-down assay. As a result, miR-375-3p was upregulated and FOXP1/Bcl2l2 was downregulated in maternal serum of women with fetal CHD and hypoxia-induced rat cardiomyocyte h9c2 cells. Hypoxia induced apoptosis rate elevation, caspase-3 activity promotion and viability inhibition in h9c2 cells; overexpression of miR-375-3p promoted, whereas knockdown of miR-375-3p antagonized hypoxia-induced effects in h9c2 cells. In addition, miR-375-3p was validated to negatively regulate FOXP1 and Bcl2l2 expression through target binding, and silencing of FOXP1 and Bcl2l2 could independently abate the anti-apoptosis role of miR-375-3p knockdown in hypoxic h9c2 cells. Collectively, blocking miR-375-3p suppressed hypoxia-evoked apoptosis of cardiomyocytes by targeting and upregulating FOXP1 and Bcl2l2. Our results might suggest maternal serum miR-375-3p as a potential biomarker for prenatal detection of fetal CHD.

MiR-216a-5p alleviates chronic constriction injury-induced neuropathic pain in rats by targeting KDM3A and inactivating Wnt/β-catenin signaling pathway

Neuropathic pain is a devastating disease and exists tolerance to current available analgesics. MicroRNAs were reported to be involved in the regulation of neuropathic pain, but the biological role of miR-216a-5p in neuropathic pain remains unclear. In this study, we constructed a CCI rat model of neuropathic pain. Our results showed that the expression of miR-216a-5p was downregulated in CCI rats, and mechanical allodynia and thermal hyperalgesia in CCI rats were improved by miR-216a-5p overexpression, suggesting that miR-216a-5p overexpression alleviated neuropathic pain. Moreover, ELISA showed that miR-216a-5p overexpression inhibited concentration and mRNA expression of IL-6, TNF-α and IL-1β as well as suppressed microglial infiltration, indicating that miR-216a-5p overexpression inhibited neuroinflammation. Besides, we found that miR-216a-5p upregulation inactivated the Wnt/β-catenin signaling pathway. Furthermore, KDM3A was the downstream target of miR-216a-5p and KDM3A knockdown attenuated neuropathic pain. Finally, through rescue assay, we found that KDM3A countervailed miR-216a-5p mediated regulation of neuropathic pain via the Wnt/β-catenin signaling pathway. To sum up, our study confirmed that miR-216a-5p alleviated neuropathic pain in rats by targeting KDM3A and inactivating the Wnt/β-catenin signaling pathway, which may open a new and useful way for treatment of neuropathic pain.

H19/miR-130a-3p/DAPK1 axis regulates the pathophysiology of neonatal hypoxic-ischemia encephalopathy

Perinatal hypoxic ischemia encephalopathy (HIE) is a serious disease occurring in neonate. Growing studies have already validated the pivotal function of microRNAs (miRNAs) in a variety of diseases. However, whether miR-130a-3p participated in neonatal HIE remains vague. In this study, we planned to explore the molecular mechanism of H19/miR-130a-3p/DAPK1 axis in HIE. We established a in vivo mice model induced by middle cerebral artery occlusion/reperfusion (MCAO/R) and in vitro models of SH-SY5Y and N2a cells following oxygen-glucose deprivation and reperfusion (OGD/R) treatment. DAPK1 is widely explored in multiple diseases and bioinformatic analysis indicated miR-130a-3p potentially targeted DAPK1. We found DAPK1 expression was upregulated while miR-130a-3p expression was downregulated in HIE, MCAO/R mice model and OGD/R treated SH-SY5Y and N2a cells. Moreover, miR-130a-3p was verified to target DAPK1. DAPK1 upregulation restored the inhibitory effect of miR-130a-3p elevation on SH-SY5Y and N2a cells apoptosis as well as on cerebral damage by I/R. In addition, H19 was confirmed to bind with miR-130a-3p in SH-SY5Y and N2a cells. H19 and miR-130a-3p coordinately regulated SH-SY5Y and N2a cells apoptosis as well as cerebral damage by I/R. In conclusion, H19/miR-130a-3p/DAPK1 axis regulated the pathophysiology of neonatal HIE, suggesting potential therapeutic targets for neonatal HIE treatment.

TBX3 deficiency accelerates apoptosis in cardiomyoblasts through regulation of P21 expression

Congenital heart disease (CHD) is the most common birth defect in newborns. There is increasing evidence that apoptosis and remodeling of the cardiomyoblasts are the major pathology of CHD. Previous research found that T-box transcription factor 3 (TBX3) was compulsory for the regulation of proliferation, cell cycle arrest and apoptosis in various cells. Hence, TBX3 might be involved in the treatment of CHD. The primary aim of this study was to study the effects of TBX3 on apoptosis in aged cardiomyoblasts and investigate the latent mechanism. In the present study, we found TBX3 knockdown induced proliferation inhibition, cell cycle arrest and apoptosis accompanied by mitochondrial dysfunction in cardiomyoblasts at passage 10 to 15. Apoptosis-inducing effects of TBX3 silence could be neutralized by silencing P21 using specific siRNA. In addition, the mRNA and protein expression levels of TBX3 in the heart tissues of sporadic type CHD donors were obviously down-regulated. In conclusion, we demonstrated that TBX3 deficiency accelerated apoptosis via directly regulating P21 expression in senescent cardiomyoblasts.

miR-9 knockdown inhibits hypoxia-induced cardiomyocyte apoptosis by targeting Yap1

AIMS

Aberrantly expressed miRNAs are demonstrated to be involved in the development of congenital heart disease (CHD). miR-9 was proposed to be upregulated in cardiac tissues from CHD cases. However, the role of miR-9 in hypoxia-induced cardiomyocytes and the potential mechanism are far from being addressed.

MAIN METHODS

qRT-PCR and western blot analysis were performed to detect miR-9 and Yes-associated protein 1 (Yap1) expressions in hypoxic H9c2 cells. CCK-8, flow cytometry analysis, caspase-3/7 activity assay were applied to evaluate cell proliferation, apoptosis, and caspase-3/7 activity, respectively. The interaction between miR-9 and Yap1 was explored by luciferase reporter assay, qRT-PCR and western blot.

KEY FINDINGS

miR-9 was upregulated and Yap1 was downregulated in H9c2 cells in response to hypoxia in a time-dependent manner. Knockdown of miR-9 promoted cell proliferation, and inhibited apoptosis and caspase-3/7 activity in hypoxic H9c2 cells, while miR-9 overexpression exerted the opposite effects on hypoxic H9c2 cells. In addition, Yap1 was a direct target of miR-9 in H9c2 cells. Yap1 knockdown suppressed cell proliferation and promoted apoptosis in hypoxia-exposed H9c2 cells. Yap1 knockdown attenuated the effect of anti-miR-9 on cell proliferation and apoptosis in hypoxia-exposed H9c2 cells.

SIGNIFICANCE

miR-9 knockdown inhibited hypoxia-induced cardiomyocyte apoptosis by targeting Yap1. Our study provided a novel insight into the mechanism of the adaptation of cardiomyocytes to chronic hypoxia.