A novel long noncoding RNA FAF inhibits apoptosis via upregulating FGF9 through PI3K/AKT signaling pathway in ischemia-hypoxia cardiomyocytes

Hypoxia triggers cardiomyocyte apoptosis via regulating the m6A methylation-mediated LncMIAT/miR-708-5p/p53 axis

Long-time hypoxia induced cardiomyocyte apoptosis is an important mechanism of myocardial ischemia (MI) injury. Interestingly, long noncoding RNA myocardial infarction-associated transcript (LncMIAT) has been involved in the regulation of MI injury; however, the underlying mechanism by which LncMIAT affects the progression of hypoxia-induced cardiomyocyte apoptosis remains unclear. In the present study, hypoxia was found to promote cardiomyocyte apoptosis through an increased expression of LncMIAT in vitro. Biological investigations and dual-luciferase gene reporter assay further revealed that LncMIAT was able to bind with miR-708-5p to upregulate the p53-mediated cell death of the cardiomyocytes. Silencing of LncMIAT or overexpression of miR-708-5p led to a significant reduction in p53-mediated cardiomyocyte apoptosis. The methylated RNA immunoprecipitation (MeRIP)-qPCR results showed that hypoxia exerted its effects on LncMIAT through AKLBH5-N6-methyladenosine (m6A) methylation and therefore hypoxia was shown to trigger HL-1 cardiomyocyte apoptosis via the m6A methylation-mediated LncMIAT/miR-708-5p/p53 axis. Silencing of AKLBH5 significantly alleviated the m6A methylation-mediated LncMIAT upregulation and p53-mediated cardiomyocyte apoptosis, while promoted miR-708-5p expression. Taken together, the present study highlighted that LncMIAT could act as a key biological target during hypoxia-induced cardiomyocyte apoptosis. In addition, it was shown that hypoxia could promote cardiomyocyte apoptosis through regulation of the m6A methylation-mediated LncMIAT/miR-708-5p/p53 signaling axis.

Circular RNA-circLRP6 protects cardiomyocyte from hypoxia-induced apoptosis by facilitating hnRNPM-mediated expression of FGF-9

Coronary atherosclerosis-induced myocardial ischemia leads to cardiomyocyte apoptosis. The regulatory mechanisms for cardiomyocyte apoptosis have not been fully understood. Circular RNAs are non-coding RNAs which play important roles in heart function maintenance and progression of heart diseases by regulating gene transcription and protein translation. Here, we reported a conserved cardiac circular RNA, which is generated from the second exon of LRP6 and named circLRP62-2 . CircLRP62-2 can protect cardiomyocyte from hypoxia-induced apoptosis. The expression of circLRP62-2 in cardiomyocytes was down-regulated under hypoxia, while forced expression of circLRP62-2 inhibited cell apoptosis. Normally, circLRP62-2 was mainly localized in the nucleus. Under hypoxia, circLRP62-2 is associated with heterogeneous nuclear ribonucleoprotein M (hnRNPM) to be translocated into the cytoplasm. It recruited hnRNPM to fibroblast growth factor 9 (FGF9) mRNA to enhance the expression of FGF9 protein, promoting hypoxia-adaption and viability of cardiomyocytes. In summary, this study uncovers a new inhibitor of apoptosis and reveals a novel anti-apoptotic pathway composed of circLRP62-2 , hnRNPM, and FGF9, which may provide therapeutic targets for coronary heart disease and ischemic myocardial injury.

Apoptosis and long non-coding RNAs: Focus on their roles in Heart diseases

Heart disease is one of the principal death reasons around the world and there is a growing requirement to discover novel healing targets that have the potential to avert or manage these illnesses. On the other hand, apoptosis is a strongly controlled, cell removal procedure that has a crucial part in numerous cardiac problems, such as reperfusion injury, MI (myocardial infarction), consecutive heart failure, and inflammation of myocardium. Completely comprehending the managing procedures of cell death signaling is critical as it is the primary factor that influences patient mortality and morbidity, owing to cardiomyocyte damage. Indeed, the prevention of heart cell death appears to be a viable treatment approach for heart illnesses. According to current researches, a number of long non-coding RNAs cause the heart cells death via different methods that are embroiled in controlling the activity of transcription elements, the pathways that signals transmission within cells, small miRNAs, and the constancy of proteins. When there is too much cell death in the heart, it can cause problems like reduced blood flow, heart damage after restoring blood flow, heart disease in diabetics, and changes in the heart after reduced blood flow. Therefore, studying how lncRNAs control apoptosis could help us find new treatments for heart diseases. In this review, we present recent discoveries about how lncRNAs are involved in causing cell death in different cardiovascular diseases.

The role of lncRNA-mediated pyroptosis in cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide. Pyroptosis is a unique kind of programmed cell death that varies from apoptosis and necrosis morphologically, mechanistically, and pathophysiologically. Long non-coding RNAs (LncRNAs) are thought to be promising biomarkers and therapeutic targets for the diagnosis and treatment of a variety of diseases, including cardiovascular disease. Recent research has demonstrated that lncRNA-mediated pyroptosis has significance in CVD and that pyroptosis-related lncRNAs may be potential targets for the prevention and treatment of specific CVDs such as diabetic cardiomyopathy (DCM), atherosclerosis (AS), and myocardial infarction (MI). In this paper, we collected previous research on lncRNA-mediated pyroptosis and investigated its pathophysiological significance in several cardiovascular illnesses. Interestingly, certain cardiovascular disease models and therapeutic medications are also under the control of lncRNa-mediated pyroptosis regulation, which may aid in the identification of new diagnostic and therapy targets. The discovery of pyroptosis-related lncRNAs is critical for understanding the etiology of CVD and may lead to novel targets and strategies for prevention and therapy.

Epigenetic regulation in myocardial infarction: Non-coding RNAs and exosomal non-coding RNAs

Myocardial infarction (MI) is one of the leading causes of deaths globally. The early diagnosis of MI lowers the rate of subsequent complications and maximizes the benefits of cardiovascular interventions. Many efforts have been made to explore new therapeutic targets for MI, and the therapeutic potential of non-coding RNAs (ncRNAs) is one good example. NcRNAs are a group of RNAs with many different subgroups, but they are not translated into proteins. MicroRNAs (miRNAs) are the most studied type of ncRNAs, and have been found to regulate several pathological processes in MI, including cardiomyocyte inflammation, apoptosis, angiogenesis, and fibrosis. These processes can also be modulated by circular RNAs and long ncRNAs via different mechanisms. However, the regulatory role of ncRNAs and their underlying mechanisms in MI are underexplored. Exosomes play a crucial role in communication between cells, and can affect both homeostasis and disease conditions. Exosomal ncRNAs have been shown to affect many biological functions. Tissue-specific changes in exosomal ncRNAs contribute to aging, tissue dysfunction, and human diseases. Here we provide a comprehensive review of recent findings on epigenetic changes in cardiovascular diseases as well as the role of ncRNAs and exosomal ncRNAs in MI, focusing on their function, diagnostic and prognostic significance.

New developments in the biology of fibroblast growth factors

The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.

A novel hypoxic lncRNA, HRL-SC, promotes the proliferation and migration of human dental pulp stem cells through the PI3K/AKT signaling pathway

Background

Human dental pulp stem cells (hDPSCs) are critical for pulp generation. hDPSCs proliferate faster under hypoxia, but the mechanism by which long noncoding RNA (lncRNA) regulates this process is not fully understood.

Methods

Novel lncRNAs were obtained by reanalysis of transcriptome datasets from RNA-Seq under hypoxia compared with normoxia, and a differential expression analysis of target genes was performed. Bioinformatics analyses, including gene ontology analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis and gene set enrichment analysis, were used to understand the function of key novel lncRNAs. hDPSCs were isolated from dental pulp tissue. EdU and scratch wound healing assays were used to detect the proliferation and migration of hDPSCs. qRT-PCR was used to detect changes in the RNA expression of selected genes. RNA fluorescence in situ hybridization, small interfering RNA, qRT-PCR and Western blot analysis were used to explore the function of key novel lncRNAs.

Results

We identified 496 novel lncRNAs in hDPSCs under hypoxia, including 45 differentially expressed novel lncRNAs. Of these, we focused on a key novel lncRNA, which we designated HRL-SC (hypoxia-responsive lncRNA in stem cells). Functional annotation revealed that HRL-SC was associated with hypoxic conditions and the PI3K/AKT signaling pathway. HRL-SC was mainly located in the cytoplasm of hDPSCs and had stable high expression under hypoxia. Knockdown of HRL-SC inhibited the proliferation and migration of hDPSCs and the expression levels of PI3K/AKT-related marker proteins. Furthermore, the AKT activator SC79 partially offset the inhibitory effect caused by the knockdown, indicating that HRL-SC promoted hDPSCs through the PI3K/AKT signaling pathway.

Conclusions

Hypoxia-responsive lncRNA HRL-SC promotes the proliferation and migration of hDPSCs through the PI3K/AKT signaling pathway, and this understanding may facilitate the regenerative application of hDPSCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02970-5.

Integrative Analysis of the lncRNA-Associated ceRNA Regulatory Network Response to Hypoxia in Alveolar Type II Epithelial Cells of Tibetan Pigs

The function of alveolar type II epithelial (ATII) cells is severely hampered by oxygen deficiency, and understanding the regulatory mechanisms controlling responses to hypoxia may assist in relieving injury induced by hypoxia. In this study, we cultured ATII cells from Tibetan pigs and Landrace pigs under hypoxic and normoxic environments to screen for differentially expressed (DE) lncRNAs, DEmiRNAs, and construct their associated ceRNA regulatory networks in response to hypoxia. Enrichment analysis revealed that target genes of DElncRNAs of Tibetan pigs and Landrace pig between the normoxic (TN, LN) and hypoxic (TL, LL) groups significantly enriched in the proteoglycans in cancer, renal cell carcinoma, and erbB signaling pathways, while the target genes of DEmiRNAs were significantly enriched in the axon guidance, focal adhesion, and mitogen-activated protein kinase (MAPK) signaling pathways. Hypoxia induction was shown to potentially promote apoptosis by activating the focal adhesion/PI3K-Akt/glycolysis pathway. The ssc-miR-20b/MSTRG.57127.1/ssc-miR-7-5p axis potentially played a vital role in alleviating hypoxic injury by regulating ATII cell autophagy under normoxic and hypoxic conditions. MSTRG.14861.4-miR-11971-z-CCDC12, the most affected axis, regulated numerous RNAs and may thus regulate ATII cell growth in Tibetan pigs under hypoxic conditions. The ACTA1/ssc-miR-30c-3p/MSTRG.23871.1 axis is key for limiting ATII cell injury and improving dysfunction and fibrosis mediated by oxidative stress in Landrace pigs. Our findings provide a deeper understanding of the lncRNA/miRNA/mRNA regulatory mechanisms of Tibetan pigs under hypoxic conditions.

MiR-107 Aggravates Oxygen-Glucose Deprivation/Reoxygenation (OGD/R)-Induced Injury Through Inactivating PI3K-AKT Signalling Pathway by Targeting FGF9/FGF12 in PC12 Cells

OBJECTIVES

The aberrant expression of miR-107 has been confirmed in some neurological diseases, including ischemic stroke (IS). However, the function of miR-107 and underlying mechanisms are ambiguous.

MATERIALS AND METHODS

Oxygen-Glucose Deprivation/Reoxygenation (OGD/R)-induced PC12 cells were used to mimic IS condition. MiR-107 expression and differentially expressed genes (DEGs) responding to IS were analyzed by GSE97532 and GSE61616 datasets, respectively. The target genes of miR-107 were predicted by TargetScan and confirmed by dual-luciferase reporter assay. Cell counting kit-8 and apoptosis assays were conducted to explore the role of miR-107 in biological behaviors of OGD/R-induced PC12 cells.

RESULTS

Bioinformatics analysis revealed that miR-107 expression was elevated in rats with middle cerebral artery occlusion (MCAO), which was confirmed in OGD/R-treated PC12 cells. Notably, miR-107 strongly inhibited the proliferation of OGD/R-treated PC12 cells. As most DEGs were enriched in PI3K-AKT signaling pathway, which was critical for IS, DEGs in this pathway was compared with the down-regulated genes and the predicted genes to obtain potential target genes of miR-107, and ultimately fibroblast growth factor (FGF)9 and FGF12 stood out. The experiments demonstrated that miR-107 inhibited viability and promoted apoptosis of OGD/R-treated PC12 cells by down-regulating FGF9/FGF12 level. Mechanically, for the first time, we clarified the mechanism via which miR-107 inactivated PI3K-AKT signaling pathway by targeting FGF9/FGF12.

CONCLUSIONS

We summarized that miR-107 aggravates OGD/R-induced injury through inactivating PI3K-AKT signaling pathway via targeting FGF9/FGF12. Therefore, our study elucidates the neurotoxicity of miR-107 in IS development and provides a new promising therapy strategy for IS.

Long Noncoding RNAs Involved in Cardiomyocyte Apoptosis Triggered by Different Stressors

Cardiomyocytes are essential to maintain the normal cardiac function. Ischemia, hypoxia, and drug stimulation can induce pathological apoptosis of cardiomyocytes which eventually leads to heart failure, arrhythmia, and other cardiovascular diseases. Understanding the molecular mechanisms that regulate cardiomyocyte apoptosis is of great significance for the prevention and treatment of cardiovascular diseases. In recent years, more and more evidences reveal that long noncoding RNAs (lncRNAs) play important regulatory roles in myocardial cell apoptosis. They can modulate the expression of apoptosis-related genes at post-transcriptional level by altering the translation efficacy of target mRNAs or functioning as a precursor for miRNAs or competing for miRNA-mediated inhibition. Moreover, reversing the abnormal expression of lncRNAs can attenuate and even reverse the pathological apoptosis of cardiomyocytes. Therefore, apoptosis-related lncRNAs may become a potential new field for studying cardiomyocyte apoptosis and provide new ideas for the treatment of cardiovascular diseases.

The Roles of lncRNA in Myocardial Infarction: Molecular Mechanisms, Diagnosis Biomarkers, and Therapeutic Perspectives

In recent years, long non-coding RNAs (lncRNAs) have been demonstrated to be associated with many physiological and pathological processes in cardiac. Recent studies have shown that lncRNAs are expressed dynamically in cardiovascular diseases and participate in regulation through a variety of molecular mechanisms, which have become a critical part of the epigenetic and transcriptional regulatory pathways in heart development, as well as the initiation and progress of myocardial infarction. In this review, we summarized some current research about the roles of lncRNAs in heart development and myocardial infarction, with the emphasis on molecular mechanisms of pathological responses, and highlighted their functions in the secondary changes of myocardial infarction. We also discussed the possibility of lncRNAs as novel diagnostic biomarkers and potential therapeutic targets for myocardial infarction.

Long non-coding RNA LUCAT1 inhibits myocardial oxidative stress and apoptosis after myocardial infarction via targeting microRNA-181a-5p

This study hoped to explore the effects and mechanism of long non-coding RNA (lncRNA) LUCAT1 regulating microRNA-181a-5p (miR-181a-5p) on oxidative stress and apoptosis of cardiomyocytes induced by H₂O₂. Totally, 72 patients with acute myocardial infarction (AMI) were included. H9c2 cardiomyocytes were cultured in vitro, and the H₂O₂ model of cardiomyocytes was established. The expression levels of LUCAT1 and miR-181a-5p were detected by qRT-PCR after H₂O₂ induction. The contents of reactive oxygen species (ROS), superoxide dismutase (SOD), and malondialdehyde (MDA) in cells were detected. The survival rate of the cells was detected by the Cell Counting Kit-8 (CCK-8) method; the apoptosis was detected by flow cytometry. The luciferase reporter experiment and quantitative real-time PCR (qRT-PCR) were used to verify the targeted relationship between LUCAT1 and miR-181a-5p. LUCAT1 was lowly expressed in the AMI patients. After H₂O₂ induction, the expression of LUCAT1 in H9c2 cells lessened significantly, while the expression of miR-181a-5p elevated significantly (P < 0.001). Transfection of p-LUCAT1 significantly reversed the decreased SOD levels, the increased MDA and ROS content, and the elevated tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) in H₂O₂-stimulated cells (P < 0.001). Upregulation of LUCAT1 contributed to the mitigation of H₂O₂ injury by promoting viable cells and repressing apoptotic cells (P < 0.01). LUCAT1 targeted miR-181a-5p and negatively regulated miR-181a-5p expression (P < 0.001). Collectively, LUCAT1 played a protective role on oxidative stress injury, inflammation, viability, and apoptosis of cardiomyocytes induced by H₂O₂ via regulating miR-181a-5p.

Role of long non-coding RNAs in adipogenesis: State of the art and implications in obesity and obesity-associated diseases

Obesity is an evolutionary, chronic, and relapsing disease that consists of a pathological accumulation of adipose tissue able to increase morbidity for high blood pressure, type 2 diabetes, metabolic syndrome, and obstructive sleep apnea in adults, children, and adolescents. Despite intense research over the last 20 years, obesity remains today a disease with a complex and multifactorial etiology. Recently, long non-coding RNAs (lncRNAs) are emerging as interesting new regulators as different lncRNAs have been found to play a role in early and late phases of adipogenesis and to be implicated in obesity-associated complications onset. In this review, we discuss the most recent advances on the role of lncRNAs in adipocyte biology and in obesity-associated complications. Indeed, more and more researchers are focusing on investigating the underlying roles that these molecular modulators could play. Even if a significant number of evidence is correlation-based, with lncRNAs being differentially expressed in a specific disease, recent works are now focused on deeply analyzing how lncRNAs can effectively modulate the disease pathogenesis onset and progression. LncRNAs possibly represent new molecular markers useful in the future for both the early diagnosis and a prompt clinical management of patients with obesity.

Expression and function of FGF9 in the hypertrophied ligamentum flavum of lumbar spinal stenosis patients

BACKGROUND CONTEXT

Ligamentum flavum (LF) hypertrophy plays a dominant role in lumbar spinal stenosis (LSS). A previous study found that fibroblast growth factor 9 (FGF9) was upregulated with mechanical stress in rabbit LF. However, the expression and function of FGF9 are not well understood in human LF.

PURPOSE

To evaluate FGF9 expression and function in human LF with and without hypertrophy.

STUDY DESIGN

This study employed a basic research study design utilizing human LF tissue for histological analyses.

PATIENT SAMPLES

Hypertrophied LF tissue sample from patients with LSS, and nonhypertrophied (control) LFs from patients with lumbar disc herniation or other diseases were obtained during surgery.

METHODS

LF specimens were histologically analyzed for FGF9 and vascular endothelial growth factor A (VEGF-A) by immunohistochemistry. The number of total and FGF9 immuno-positive cells and blood vessels were counted and compared between LF with and without hypertrophy. For functional analysis, the effect of FGF9 on cell proliferation and migration was examined using a primary cell culture of human LF.

RESULTS

Histological studies revealed that the total cell number was significantly higher in the LF of patients with LSS than in the LF of control patients. Immunohistochemistry showed that the percentage of FGF9-positive cells was significantly higher in the LF of patients with LSS than in the controls, and it positively correlated with patients' age, regardless of disease. Double immune-positive cells for FGF9 and VEGF-A were often observed in vascular endothelial cells and fibroblasts in the fibrotic area of hypertrophied LF, and the number of double positive vessels was significantly higher in LF of LSS patients than in the LF of controls. Primary cell culture of human LF revealed that FGF9 promoted the proliferation and migration of LF cells.

CONCLUSION

The present study demonstrated that FGF9 expression is highly upregulated in hypertrophied human LF. FGF9 potentially plays a pivotal role in the process of hypertrophy of LF, which is associated with mechanical stress, through cell proliferation and migration.

CLINICAL SIGNIFICANCE

The results from this study partially reveal the molecular mechanisms of LF hypertrophy and suggest that FGF9 may be involved in the process of LF degeneration in elderly patients.

lncRNA NORAD promotes the progression of osteosarcoma via targeting of miR-155-5p

Osteosarcoma (OS) is the most common malignant bone tumor in teens. Non-coding RNA activated by DNA damage (NORAD), a long non-coding RNA (lncRNA), has been reported to be involved in cancer biology, although its role in OS remains largely unknown. In the present study reverse transcription-quantitative PCR (RT-qPCR) was used to determine the expression levels of NORAD and miR-155-5p in samples from patients with OS. OS cell lines (Saos-2 and U2OS) were used as cell models. The biological influence of NORAD on OS cells was studied in vitro using Cell Counting Kit-8 and Transwell assays. The interaction between NORAD and miR-155-5p was clarified by bioinformatics analysis, RT-qPCR, luciferase reporter assay and RNA immunoprecipitation. NORAD was significantly increased in OS samples in comparison with controls, while miR-155-5p was reduced. Knockdown of NORAD and transfection of miR-155-5p mimics markedly inhibited the viability, migration and invasion of OS cells. There was a negative correlation between NORAD and miR-155-5p expression levels in OS samples. Taken together, the results of the present study indicated that the NORAD/miR-155-5p axis played a crucial role in regulating the proliferation, migration and invasion of OS cells. It is hypothesized that NORAD and miR-155-5p may serve as potential novel therapeutic targets for OS management.

Long Noncoding RNAs in Myocardial Ischemia-Reperfusion Injury

Following an acute myocardial infarction, reperfusion therapy is currently the most effective way to save the ischemic myocardium; however, restoring blood flow may lead to a myocardial ischemia-reperfusion injury (MIRI). Recent studies have confirmed that long-chain noncoding RNAs (LncRNAs) play important roles in the pathophysiology of MIRIs. These LncRNA-mediated roles include cardiomyocyte apoptosis, autophagy, necrosis, oxidative stress, inflammation, mitochondrial dysfunction, and calcium overload, which are regulated through the expression of target genes. Thus, LncRNAs may be used as clinical diagnostic markers and therapeutic targets to treat or prevent MIRI. This review evaluates the research on LncRNAs involved in MIRIs and provides new ideas for preventing and treating this type of injury.

Cardiac Exosomes in Ischemic Heart Disease- A Narrative Review

Ischemic heart disease (IHD) is the primary cause of death globally. IHD is associated with the disruption of blood supply to the heart muscles, which often results in myocardial infarction (MI) that further may progress to heart failure (HF). Exosomes are a subgroup of extracellular vesicles that can be secreted by virtually all types of cells, including cardiomyocytes, cardiac fibroblasts, endothelial cells, and stem and progenitor cells. Exosomes represent an important means of cell–cell communication through the transport of proteins, coding and non-coding RNA, and other bioactive molecules. Several studies show that exosomes play an important role in the progression of IHD, including endothelial dysfunction, the development of arterial atherosclerosis, ischemic reperfusion injury, and HF development. Recently, promising data have been shown that designates exosomes as carriers of cardioprotective molecules that enhance the survival of recipient cells undergoing ischemia. In this review, we summarize the functional involvement of exosomes regarding IHD. We also highlight the cardioprotective effects of native and bioengineered exosomes to IHD, as well as the possibility of using exosomes as natural biomarkers of cardiovascular diseases. Lastly, we discuss the opportunities and challenges that need to be addressed before exosomes can be used in clinical applications.

Analysis on the Expression and Prognostic Value of LncRNA FAF in Patients with Coronary Heart Disease

Objective

To investigate the expression and prognostic value of LncRNA FAF in patients with coronary heart disease. Patients and Methods. 97 patients with coronary heart disease who came to our hospital were selected as the research group (RG), and 97 healthy people who came to our hospital for physical examination during the same period were selected as the control group (CG). The serum LncRNA FAF, plasma homocysteine (HCY), lipoprotein A (Lp-a), serum tumor necrosis factor α (TNF-α), and high-sensitivity C-reactive protein (hsCRP) in the two groups of patients were detected, and their correlations were analyzed. Then, the predictive value and risk factors of FAF for poor prognosis of patients with coronary heart disease were analyzed.

Results

The expression of LncRNA FAF in the serum of patients in the RG was significantly lower than that in the CG, and the expressions of HCY, Lp-a, TNF-α, and hsCRP were significantly higher than those in the CG (p <0.05). The AUC of FAF in the diagnosis of coronary heart disease was more than 0.9. FAF was negatively correlated with the coronary lesion vessels, HCY, Lp-a, TNF-α, and hsCRP expressions in patients with coronary heart disease (p < 0.05). The ROC of FAF for predicting poor prognosis in patients with coronary heart disease was greater than 0.9. Low expression of FAF; high expressions of HCY, Lp-a, and hsCRP; and increase of coronary lesion vessels were independent risk factors for poor prognosis in patients with coronary heart disease.

Conclusions

LncRNA FAF was lowly expressed in the serum of patients with coronary heart disease, and it was of high value in the diagnosis and prediction of poor prognosis of coronary heart disease. It was also an independent risk factor for poor prognosis of patients with coronary heart disease and may be a potential target for diagnosis and treatment of coronary heart disease.

The roles of long noncoding RNAs in myocardial pathophysiology

Long noncoding RNAs (lncRNAs), more than 200 nt in length, are functional molecules found in various species. These lncRNAs play a vital role in cell proliferation, differentiation, and degeneration and are also involved in pathophysiological processes of cancer and neurodegenerative, autoimmune, and cardiovascular diseases (CVDs). In recent years, emerging challenges for intervention studies on ischemic heart diseases have received much attention. LncRNAs have a key function in the alleviation of myocardial infarction (MI) injury and myocardial ischemia–reperfusion injury. During cardiac hypertrophy (CH) and fibrosis, cardiac cells undergo structural changes and become dysfunctional due to the effects of neurohormonal factors. LncRNAs may serve as important therapeutic targets that promote cardiac remodeling and then retard the development of heart failure (HF). In addition, studies on the roles and mechanisms of action of lncRNAs participating in cardiac pathophysiology via other factors have become the focus of research worldwide. Here, we review the current knowledge on various lncRNAs and their functions in cardiac biology, particularly concentrating on ischemic heart disease, CH, and cardiac fibrosis. We next discuss the predictive value of lncRNAs as diagnostic biomarkers of CVDs.

Donor MSCs release apoptotic bodies to improve myocardial infarction via autophagy regulation in recipient cells

Mesenchymal stem cell (MSC) transplantation has been widely applied as a potential therapeutic for multiple diseases. However, the underlying therapeutic mechanisms are not fully understood, especially the paradox between the low survival rate of transplanted cells and the beneficial therapeutic effects generated by these cells. Herein, in a myocardial infarction (MI) model, we found that transplanted MSCs released apoptotic bodies (ABs) to enhance angiogenesis and improve cardiac functional reclovery via regulating macroautophagy/autophagy in the recipient endothelial cells (ECs). Mechanistically, after local transplantation, MSCs underwent extensive apoptosis in the short term and released ABs, which were engulfed by the recipient ECs. Then, in the ECs, ABs activated lysosome functions and promoted the expression of TFEB (transcription factor EB), which is a master gene in lysosomal biogenesis and autophagy. Finally, the increase in TFEB enhanced autophagy-related gene expression in ECs and promoted angiogenesis and cardiac functional recovery after MI. Collectively, we found that apoptotic donor MSCs promote angiogenesis via regulating autophagy in the recipient ECs, unveiling the role of donor cell apoptosis in the therapeutic effects generated by cell transplantation. Abbreviations: 3-MA: 3-methyladenine; ABs: apoptotic bodies; BECN1: beclin 1; CASP3: caspase 3; CQ: chloroquine; ECs: endothelial cells; EVs: extracellular vesicles; LAMP1: lysosomal-associated membrane protein 1; LVEF: left ventricular ejection fraction; LVFS: left ventricular fractional shortening; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MI: myocardial infarction; MSC: mesenchymal stem cell; NO: nitric oxide; TFEB: transcription factor EB; TUNEL: TdT-mediated dUTP Nick-End Labeling.

LncRNA FAF inhibits fibrosis induced by angiotensinogen II via the TGFβ1-P-Smad2/3 signalling by targeting FGF9 in cardiac fibroblasts

The dysregulation of Long noncoding RNAs (lncRNAs) has been implicated in many cardiovascular diseases, including cardiac fibrosis. However, the functions and mechanisms of lncRNAs in cardiac fibroblasts (CFs) have not been fully elucidated. First, we observed a correlation between cardiac remodeling (CR) and lncRNA FAF (FGF9-associated factor, termed FAF) expression in the heart. In vitro, we found that the expression of lncRNA FAF was altered in CFs, whereas it behaved inconsistently in cardiomyocytes (CMs). Next, we investigated the effects of lncRNA FAF on angiotensinogen II (Ang II)-induced cardiac fibrosis in neonatal rat CFs and explored the mechanism underlying these effects. In this study, lncRNA FAF was enriched in CFs and was associated with cardiac fibrosis. Upregulation of lncRNA FAF significantly restrained Ang II-induced increases in cell proliferation, differentiation and collagen accumulation of CFs. Moreover, we found that the function of lncRNA FAF was mainly realized through Transforming growth factor β1 (TGFβ1) secretion and then downregulated phosphorylation of Smad2/3. Additional analysis revealed that Fibroblast growth factor 9 (FGF9) is a direct target of lncRNA FAF, as the overexpression of lncRNA FAF could increase the expression of FGF9 and knockdown of the FGF9 expression could attenuate the down-regulation of lncRNA FAF on TGFβ1-P-Smad2/3 pathway. Furthermore, knockdown of the FGF9 expression also abolished the inhibitory effect of FAF on fibrosis. In summary, we demonstrated that the overexpression of lncRNA FAF could inhibit fibrosis induced by Ang II via the TGFβ1-P-Smad2/3 signalling by targeting FGF9 in CFs.