LncRNA AFAP1-AS Functions as a Competing Endogenous RNA to Regulate RAP1B Expression by sponging miR-181a in the HSCR

The roles of non-coding RNAs in Hirschsprung's disease

Hirschsprung's disease (HSCR) is a congenital disorder characterized by the absence of ganglion cells in the colon, leading to various intestinal complications. The etiology of HSCR stems from complex genetic and environmental interactions, of which the intricate roles of non-coding RNAs (ncRNAs) are a key area of research. However, the roles of ncRNAs in the pathogenesis of HSCR have not been fully elucidated. In order to understand the variety of symptoms caused by HSCR and develop new therapeutic approaches, it is essential to understand the underlying biological genetic basis of HSCR. This review presents a comprehensive overview of the current understanding regarding the involvement of ncRNAs in HSCR, including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs). Additionally, it provides a summary of the molecular mechanisms through which ncRNAs regulate the expression of genes related to the proliferation, migration, and differentiation of intestinal neural crest cells, thereby contributing to the advancement of HSCR research.

The Role of the MiR-181 Family in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fourth-leading cause of cancer-related death worldwide. Due to the high mortality rate in HCC patients, discovering and developing novel systemic treatment options for HCC is a vital unmet medical need. Among the numerous molecular alterations in HCCs, microRNAs (miRNAs) have been increasingly recognised to play critical roles in hepatocarcinogenesis. We and others have recently revealed that members of the microRNA-181 (miR-181) family were up-regulated in some, though not all, human cirrhotic and HCC tissues-this up-regulation induced epithelial-mesenchymal transition (EMT) in hepatocytes and tumour cells, promoting HCC progression. MiR-181s play crucial roles in governing the fate and function of various cells, such as endothelial cells, immune cells, and tumour cells. Previous reviews have extensively covered these aspects in detail. This review aims to give some insights into miR-181s, their targets and roles in modulating signal transduction pathways, factors regulating miR-181 expression and function, and their roles in HCC.

Bioinformatics Prediction for Network-Based Integrative Multi-Omics Expression Data Analysis in Hirschsprung Disease

Hirschsprung's disease (HSCR) is a rare developmental disorder in which enteric ganglia are missing along a portion of the intestine. HSCR has a complex inheritance, with RET as the major disease-causing gene. However, the pathogenesis of HSCR is still not completely understood. Therefore, we applied a computational approach based on multi-omics network characterization and clustering analysis for HSCR-related gene/miRNA identification and biomarker discovery. Protein-protein interaction (PPI) and miRNA-target interaction (MTI) networks were analyzed by DPClusO and BiClusO, respectively, and finally, the biomarker potential of miRNAs was computationally screened by miRNA-BD. In this study, a total of 55 significant gene-disease modules were identified, allowing us to propose 178 new HSCR candidate genes and two biological pathways. Moreover, we identified 12 key miRNAs with biomarker potential among 137 predicted HSCR-associated miRNAs. Functional analysis of new candidates showed that enrichment terms related to gene ontology (GO) and pathways were associated with HSCR. In conclusion, this approach has allowed us to decipher new clues of the etiopathogenesis of HSCR, although molecular experiments are further needed for clinical validations.

Sequencing Reveals miRNAs Enriched in the Developing Mouse Enteric Nervous System

The enteric nervous system (ENS) is an essential network of neurons and glia in the bowel wall. Defects in ENS development can result in Hirschsprung disease (HSCR), a life-threatening condition characterized by severe constipation, abdominal distention, bilious vomiting, and failure to thrive. A growing body of literature connects HSCR to alterations in miRNA expression, but there are limited data on the normal miRNA landscape in the developing ENS. We sequenced small RNAs (smRNA-seq) and messenger RNAs (mRNA-seq) from ENS precursor cells of mid-gestation Ednrb-EGFP mice and compared them to aggregated RNA from all other cells in the developing bowel. Our smRNA-seq results identified 73 miRNAs that were significantly enriched and highly expressed in the developing ENS, with miR-9, miR-27b, miR-124, miR-137, and miR-488 as our top 5 miRNAs that are conserved in humans. However, contrary to prior reports, our follow-up analyses of miR-137 showed that loss of Mir137 in Nestin-cre, Wnt1-cre, Sox10-cre, or Baf53b-cre lineage cells had no effect on mouse survival or ENS development. Our data provide important context for future studies of miRNAs in HSCR and other ENS diseases and highlight open questions about facility-specific factors in development.

Overexpression of ST7-AS1 Enhances Apoptosis and Inhibits Proliferation of Papillary Thyroid Carcinoma Cells Via microRNA-181b-5p-Dependent Inhibition Tripartite Motif Containing 3

Long non-coding RNAs (lncRNAs) are of great significance in the pathogenesis and progression of papillary thyroid carcinoma (PTC). LncRNA tumorigenicity 7 antisense RNA 1 (ST7-AS1) is a newly identified lncRNA serving as an oncogene or tumor suppressor in different tumors; however, the role of ST7-AS1 in PTC remains completely unknown. In this study, ST7-AS1 was mainly distributed in the cytoplasm of PTC cells and presented reduced expression in THCA tumors and PTC cell lines. Functional experiments revealed that overexpressed ST7-AS1 inhibited the viability and proliferation of PTC cells, whereas accelerated the apoptosis of PTC cells. The expression of miR-181b-5p was upregulated and it bound with ST7-AS1 in PTC cells. Moreover, TRIM3 exhibited downregulated expression level in PTC cells and ST7-AS1 elevated TRIM3 expression via harboring miR-181b-5p. Rescue experiments illuminated that knockdown of TRIM3 reversed ST7-AS1 overexpression-induced promotion on PTC cell proliferation and suppression on PTC cell apoptosis. Overall, overexpression of ST7-AS1 enhances apoptosis and represses proliferation of PTC cells via targeting the miR-181b-5p/TRIM3 axis, which may help broaden the horizon and establish the foundation to develop therapeutic strategies for PTC in the future.

Identifying the potential transcriptional regulatory network in Hirschsprung disease by integrated analysis of microarray datasets

Objective

Hirschsprung disease (HSCR) is one of the common neurocristopathies in children, which is associated with at least 20 genes and involves a complex regulatory mechanism. Transcriptional regulatory network (TRN) has been commonly reported in regulating gene expression and enteric nervous system development but remains to be investigated in HSCR. This study aimed to identify the potential TRN implicated in the pathogenesis and diagnosis of HSCR.

Methods

Based on three microarray datasets from the Gene Expression Omnibus database, the multiMiR package was used to investigate the microRNA (miRNA)-target interactions, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Then, we collected transcription factors (TFs) from the TransmiR database to construct the TF-miRNA-mRNA regulatory network and used cytoHubba to identify the key modules. Finally, the receiver operating characteristic (ROC) curve was determined and the integrated diagnostic models were established based on machine learning by the support vector machine method.

Results

We identified 58 hub differentially expressed microRNAs (DEMis) and 16 differentially expressed mRNAs (DEMs). The robust target genes of DEMis and DEMs mainly enriched in several GO/KEGG terms, including neurogenesis, cell-substrate adhesion, PI3K-Akt, Ras/mitogen-activated protein kinase and Rho/ROCK signaling. Moreover, 2 TFs (TP53 and TWIST1), 4 miRNAs (has-miR-107, has-miR-10b-5p, has-miR-659-3p, and has-miR-371a-5p), and 4 mRNAs (PIM3, CHUK, F2RL1, and CA1) were identified to construct the TF-miRNA-mRNA regulatory network. ROC analysis revealed a strong diagnostic value of the key TRN regulons (all area under the curve values were more than 0.8).

Conclusion

This study suggests a potential role of the TF-miRNA-mRNA network that can help enrich the connotation of HSCR pathogenesis and diagnosis and provide new horizons for treatment.

Cell Division Control Protein 42 Interacts With Hepatitis E Virus Capsid Protein and Participates in Hepatitis E Virus Infection

Hepatitis E Virus (HEV) causes viral hepatitis in humans worldwide, while a subset of HEV species, avian HEV, causes hepatitis-splenomegaly syndrome in chickens. To date, there are few reports on the host proteins interacting with HEV and being involved in viral infection. Previous pull-down assay combining mass spectrometry indicated that cell division control protein 42 (CDC42), a member belonging to the Rho GTPase family, was pulled down by avian HEV capsid protein. We confirmed the direct interaction between CDC42 and avian and mammalian HEV capsid proteins. The interaction can increase the amount of active guanosine triphosphate binding CDC42 state (GTP-CDC42). Subsequently, we determined that the expression and activity of CDC42 were positively correlated with HEV infection in the host cells. Using the different inhibitors of CDC42 downstream signaling pathways, we found that CDC42-MRCK (a CDC42-binding kinase)-non-myosin IIA (NMIIA) pathway is involved in naked avian and mammalian HEV infection, CDC42-associated p21-activated kinase 1 (PAK1)-NMIIA/Cofilin pathway is involved in quasi-enveloped mammalian HEV infection and CDC42-neural Wiskott-Aldrich syndrome protein-actin-polymerizing protein Arp2/3 pathway (CDC42-(N-)WASP-Arp2/3) pathway participates in naked and quasi-enveloped mammalian HEV infection. Collectively, these results demonstrated for the first time that HEV capsid protein can directly bind to CDC42, and non- and quasi-enveloped HEV use different CDC42 downstream signaling pathways to participate in viral infection. The study provided some new insights to understand the life cycle of HEV in host cells and a new target of drug design for combating HEV infection.

LncRNA AFAP1-AS1/miR-27b-3p/VEGF-C axis modulates stemness characteristics in cervical cancer cells

Background:

Long non-coding RNA (lncRNA) actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) functions as a competing endogenous RNA to regulate target genes expression by sponging microRNAs (miRs) to play cancer-promoting roles in cancer stem cells. However, the regulatory mechanism of AFAP1-AS1 in cervical cancer (CC) stem cells is unknown. The present study aimed to provide a new therapeutic target for the clinical treatment of CC.

Methods:

Hyaluronic acid receptor cluster of differentiation 44 variant exon 6 (CD44v6)(+) CC cells were isolated by flow cytometry (FCM). Small interfering RNAs of AFAP1-AS1 (siAFAP1-AS1) were transfected into the (CD44v6)(+) cells. The levels of AFAP1-AS1 were measured by quantitative real-time PCR (qRT-PCR). Sphere formation assay, cell cycle analysis, and Western blotting were used to detect the effect of siAFAP1-AS1. RNA pull-down and luciferase reporter assay were used to verify the relationship between miR-27b-3p and AFAP1-AS1 or vascular endothelial growth factor (VEGF)-C.

Results:

CD44v6(+) CC cells had remarkable stemness and a high level of AFAP1-AS1. However, AFAP1-AS1 knockdown with siAFAP1-AS1 suppressed the cell cycle transition of G(1)/S phase and inhibited self-renewal of CD44v6(+) CC cells, the levels of the stemness markers octamer-binding transcription factor 4 (OCT4), osteopontin (OPN), and cluster of differentiation 133 (CD133), and the epithelial-mesenchymal transition (EMT)-related proteins Twist1, matrix metalloprotease (MMP)-9, and VEGF-C. In the mechanism study, miR-27b-3p/VEGF-C signaling was demonstrated to be a key downstream of AFAP1-AS1 in the CD44v6(+) CC cells.

Conclusions:

LncRNA AFAP1-AS1 knockdown inhibits the CC cell stemness by upregulating miR-27b-3p to suppress VEGF-C.

AFAP1-AS1: a rising star among oncogenic long non-coding RNAs

Long non-coding RNAs (lncRNAs) have become a hotspot in biomedical research. This interest reflects their extensive involvement in the regulation of the expression of other genes, and their influence on the occurrence and development of a variety of human diseases. Actin filament associated protein 1-Antisense RNA 1(AFAP1-AS1) is a recently discovered oncogenic lncRNA. It is highly expressed in a variety of solid tumors, and regulates the expression of downstream genes and signaling pathways through adsorption and competing microRNAs, or by the direct binding to other proteins. Ultimately, AFAP1-AS1 promotes proliferation, chemotherapy resistance, and resistance to apoptosis, maintains stemness, and enhances invasion and migration of tumor cells. This paper summarizes the research concerning AFAP1-AS1 in malignant tumors, including the clinical application prospects of AFAP1-AS1 as a potential molecular marker and therapeutic target of malignant tumors. We also discuss the limitations in the knowledge of AFAP1-AS1 and directions of further research. AFAP1-AS1 is expected to provide an example for studies of other lncRNA molecules.

Bioinformatics analysis of a TF-miRNA-lncRNA regulatory network in major depressive disorder

Major depressive disorder (MDD) is a highly prevalent disease and one of the main causes of disability worldwide. Although many studies have partially revealed the occurrence and development process of MDD, the pathogeny and molecular mechanisms are not fully understood. Weighted gene coexpression network analysis (WGCNA) was used to explore the co-expression modules and hub genes in MDD. A protein-protein interaction (PPI) network of the most significant module and a TF-miRNA-lncRNA regulatory network of MDD were constructed using bioinformatics analysis tools. A KEGG pathway and gene ontology (GO) functional enrichment analysis of the genes in the significant module was performed using DAVID. Five hub genes in the PPI network and 10 genes in the TF-miRNA-lncRNA regulatory network with high degree values were identified, which may provide new insights for the investigation of key pathways, diagnostic bio-markers, and therapeutic targets of MDD. This study brings a novel perspective and provides valuable information to explore the molecular mechanism of MDD.

Genome-wide analysis of DNA methylation in Hirschsprung enteric precursor cells: unraveling the epigenetic landscape of enteric nervous system development

Background

Hirschsprung disease (HSCR, OMIM 142623) is a rare congenital disorder that results from a failure to fully colonize the gut by enteric precursor cells (EPCs) derived from the neural crest. Such incomplete gut colonization is due to alterations in EPCs proliferation, survival, migration and/or differentiation during enteric nervous system (ENS) development. This complex process is regulated by a network of signaling pathways that is orchestrated by genetic and epigenetic factors, and therefore alterations at these levels can lead to the onset of neurocristopathies such as HSCR. The goal of this study is to broaden our knowledge of the role of epigenetic mechanisms in the disease context, specifically in DNA methylation. Therefore, with this aim, a Whole-Genome Bisulfite Sequencing assay has been performed using EPCs from HSCR patients and human controls.

Results

This is the first study to present a whole genome DNA methylation profile in HSCR and reveal a decrease of global DNA methylation in CpG context in HSCR patients compared with controls, which correlates with a greater hypomethylation of the differentially methylated regions (DMRs) identified. These results agree with the de novo Methyltransferase 3b downregulation in EPCs from HSCR patients compared to controls, and with the decrease in the global DNA methylation level previously described by our group. Through the comparative analysis of DMRs between HSCR patients and controls, a set of new genes has been identified as potential susceptibility genes for HSCR at an epigenetic level. Moreover, previous differentially methylated genes related to HSCR have been found, which validates our approach.

Conclusions

This study highlights the relevance of an adequate methylation pattern for a proper ENS development. This is a research area that provides a novel approach to deepen our understanding of the etiopathogenesis of HSCR.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01040-6.

LncRNA ST7-AS1, by regulating miR-181b-5p/KPNA4 axis, promotes the malignancy of lung adenocarcinoma

Background

Growing evidence suggests that suppressor of tumorigenicity 7 antisense RNA 1 (ST7-AS1) is an oncogenic long noncoding RNA (lncRNA). However, little is known on its clinical significance, biological functions, or molecular mechanisms in lung adenocarcinoma (LUAD).

Methods

The expression of ST7-AS1 and miR-181b-5p were examined by qRT-PCR. The correlations between ST7-AS1 level and different clinicopathological features were analysed. In vitro, LUAD cells were examined for cell viability, migration and invasion by MTT, wound healing and Transwell assay, respectively. Epithelial-mesenchymal transition (EMT) biomarkers were detected by Western blot. The regulations between ST7-AS1, miR-181b-5p, and KPNA4 were examined by luciferase assay, RNA immunoprecipitation, RNA pulldown. Both gain- and loss-of-function strategies were used to assess the importance of different signalling molecules in malignant phenotypes of LUAD cells. The in vivo effect was analysed using the xenograft and the experimental metastasis mouse models.

Results

ST7-AS1 was upregulated in LUAD tissues or cell lines, correlated with tumours of positive lymph node metastasis or higher TNM stages, and associated with shorter overall survival of LUAD patients. ST7-AS1 essentially maintained the viability, migration, invasion, and EMT of LUAD cells. The oncogenic activities of ST7-AS1 were accomplished by sponging miR-181b-5p and releasing the suppression of the latter on KPNA4. In LUAD tissues, ST7-AS1 level positively correlated with that of KPNA4 and negatively with miR-181b-5p level. In vivo, targeting ST7-AS1 significantly inhibited xenograft growth and metastasis.

Conclusions

ST7-AS1, by regulating miR-181b-5p/KPNA4 axis, promotes the malignancy of LUAD cells. Targeting ST7-AS1 and KPNA4 or up-regulating miR-181b-5p, therefore, may benefit the treatment of LUAD.

Involvement of the lncRNA AFAP1-AS1/microRNA-195/E2F3 axis in proliferation and migration of enteric neural crest stem cells of Hirschsprung's disease

NEW FINDINGS

What is the central question of this study? Long non-coding RNAs (lncRNAs) are widely involved in the progression of Hirschsprung's disease (HSCR), but the role of actin filament associated protein 1 antisense RNA1 (AFAP1-AS1), an lncRNA, in HSCR has not been explored before. What is the main finding and its importance? Downregulation of AFAP1-AS1 blocks enteric neural crest stem cell proliferation, differentiation, migration and invasion and promotes the occurrence of HSCR via the miR-195/E2F3 axis, indicating thatAFAP1-AS might be a potential biomarker for HSCR patients.

ABSTRACT

Long non-coding RNAs (lncRNAs) are involved in several human disorders. Nevertheless, it remains unclear whether they are implicated in the phenotypes of enteric neural crest stem cells (ENCSCs) in Hirschsprung's disease (HSCR). Therefore, we designed this study to explore the pathogenicity of AFAP1-AS1 for HSCR. Microarray analysis and bioinformatic tools were used to screen out the differentially lncRNAs and microRNAs (miRNAs) in patients with HSCR. Small interference RNA transfection was applied to carry out functional experiments in ENCSCs. Cellular activities were detected by cell counting kit-8, 5-ethynyl-2'-deoxyuridine, Transwell assays and flow cytometry. Finally, rescue experiments were performed to examine the cofunction of AFAP1-AS1 and miR-195 and of miR-195 and E2F transcription factor 3 (E2F3). AFAP1-AS1 was reduced in HSCR patients. Meanwhile, knockdown of AFAP1-AS1 reduced the cell migratory and proliferative capacities and facilitated cell apoptosis along with G0/G1 phase arrest. E2F3 was diminished when miR-195 was upregulated, and AFAP1-AS1 inhibition reduced its ability to bind to miR-195. Altogether, AFAP1-AS1 silencing acts as an endogenous RNA by interacting with miR-195 to alter E2F3 expression, thus conferring repressive effects on ENCSC activity and promoting HSCR progression.

Identification of New Potential LncRNA Biomarkers in Hirschsprung Disease

Hirschsprung disease (HSCR) is a neurocristopathy defined by intestinal aganglionosis due to alterations during the development of the Enteric Nervous System (ENS). A wide spectrum of molecules involved in different signaling pathways and mechanisms have been described in HSCR onset. Among them, epigenetic mechanisms are gaining increasing relevance. In an effort to better understand the epigenetic basis of HSCR, we have performed an analysis for the identification of long non-coding RNAs (lncRNAs) by qRT-PCR in enteric precursor cells (EPCs) from controls and HSCR patients. We aimed to test the presence of a set lncRNAs among 84 lncRNAs in human EPCs, which were previously related with crucial cellular processes for ENS development, as well as to identify the possible differences between HSCR patients and controls. As a result, we have determined a set of lncRNAs with positive expression in human EPCs that were screened for mutations using the exome data from our cohort of HSCR patients to identify possible variants related to this pathology. Interestingly, we identified three lncRNAs with different levels of their transcripts (SOCS2-AS, MEG3 and NEAT1) between HSCR patients and controls. We propose such lncRNAs as possible regulatory elements implicated in the onset of HSCR as well as potential biomarkers of this pathology.

RHPN1-AS1 promotes cell proliferation and migration via miR-665/Akt3 in ovarian cancer

Recent efforts have revealed that long non-coding RNAs exert crucial roles in cancer initiation and progression. RHPN1-AS1 is a 2030 bp transcript from human chromosome 8q24, and involved in tumorigenesis in uveal melanoma and non-small cell lung cancer, but it remains unknown in ovarian cancer. This study focused on the role of RHPN1-AS1 in ovarian cancer and found that RHPN1-AS1 was up-regulated in ovarian cancer tissues and cell lines. Overexpression of RHPN1-AS1 promoted ovarian cancer cell proliferation, migration, and invasion. Mechanistically, overexpression of RHPN1-AS1 decreased the expression of miR-665 and subsequently promoted the expression of Akt3 at posttranscriptional level. Taken together, RHPN1-AS1 positively regulated the expression of Akt3 through sponging miR-665, and exerted an oncogenic role in ovarian cancer progression, and indicates that RHPN1-AS1 may be a potential therapeutic target in ovarian cancer.

Molecular function predictions and diagnostic value analysis of plasma exosomal miRNAs in Hirschsprung's disease

Aim: To discover the potential roles of plasma exosomal miRNAs in Hirschsprung's disease (HSCR) and identify potential noninvasive biomarkers for early diagnosis of HSCR. Materials & methods: Plasma samples were collected from HSCR patients and matched controls. Exosomes were isolated before high-throughput Illumina sequencing was utilized to gain a profile of dysregulated exosomal miRNAs, followed with further verification in two separate cohorts. Bioinformatics analyses were also adopted to explore the molecular functions of dysregulated miRNAs in Hirschsprung's disease. Results & conclusion: 31 dysregulated miRNAs were identified with five considered as promising HSCR signatures. Gene enrichment analysis disclosed that the upregulated miRNAs were most likely to participate in 'extracellular matrix-receptor interaction' and contribute to HSCR through interfering in cell junctions.

Profile analysis reveals endogenous RNAs regulate necrotizing enterocolitis progression

Necrotizing enterocolitis (NEC) is one of the most common and devastating gastrointestinal diseases in preterm newborns, and its underlying mechanisms remain unclear. Non-coding RNAs (ncRNAs) play critical roles in intestinal diseases; however, little is known about their roles in the development of NEC. To gain a deeper understanding of the pathophysiological mechanism of NEC, long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and mRNAs were detected in an NEC rat model. In total, 1820 lncRNAs, 118 miRNAs and 929 mRNAs were differentially expressed in NEC group. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that these molecules were enriched in apoptosis, autophagic cell death, TLR4 signaling pathway, Notch signaling pathway, and mTOR signaling pathway. These pathways are thought to be closely associated with NEC. Furthermore, a lncRNA-miRNA interaction network was constructed, and four of the novel, differentially expressed lncRNAs with large changes were randomly verified using quantitative polymerase chain reaction (qPCR). The GO and KEGG pathway analysis of these four lncRNAs showed that they were associated with the negative regulation of TLR4 signaling pathway and Notch signaling pathway. In conclusion, our study revealed that these differentially expressed lncRNAs may participate in the development of NEC via interactions with miRNAs and may serve as possible biomarkers and target genes in NEC.

LncRNA AFAP1-AS1 promotes osteoblast differentiation of human aortic valve interstitial cells through regulating miR-155/SMAD5 axis

AIM

Degenerative calcific aortic valve disease (DCAVD) is a common valve disease characterized by massive calcium deposits in the aortic valve. Osteoblast differentiation of valve interstitial cells (VICs) is responsible for the formation of calcific nodules. This study aims to explore the function and underlying mechanism of long non-coding RNA (lncRNA) AFAP1-AS1 (actin filament-associated protein 1 antisense RNA 1) in the pathogenesis of DCAVD.

METHODS

AFAP1-AS1, miR-155 and mRNA levels were detected by qRT-PCR. Protein levels were measured by Western blot. Calcification deposition was examined by Alizarin Red staining. The interaction between AFAP1-AS1 and miR-155, as well as miR-155 and SMAD5 was evaluated using luciferase reporter assay.

RESULTS

AFAP1-AS1 expression was increased both in calcified aortic valves from DCAVD patients and after osteogenic induction in human VICs. Furthermore, AFAP1-AS1 overexpression promoted osteogenic differentiation of VICs, whereas AFAP1-AS1 knockdown inhibited osteogenic differentiation. Mechanistically, AFAP1-AS1 acted as a sponge for miR-155 to elevate SMAD5 expression. Further functional assays revealed that miR-155 mimic and SMAD5 silencing effectively reversed AFAP1-AS1-promoted osteogenic differentiation of VICs.

CONCLUSION

Collectively, AFAP1-AS1 promotes osteogenic differentiation of VICs, at least in part, by sponging miR-155 to upregulate SMAD5. This study sheds new light on lncRNA-directed therapeutics in DCAVD.

Weighted Gene Coexpression Network Analysis Reveals the Critical lncRNAs and mRNAs in Development of Hirschsprung's Disease

Hirschsprung's disease (HSCR) is a common newborn defect. This study aimed to identify critical genes involved in the development of HSCR. Differently expressed genes (DEGs) of public data set GSE98502 were analyzed using paired t-test. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using Database for Annotation, Visualization and Integrated Discovery (DAVID) 6.8. Besides, Coexpression network of long noncoding RNAs (lncRNAs)-mRNAs (message RNA) were constructed using weighted gene coexpression network analysis. The key modules were filtered out by calculating the module-trait correlations. Then, hub genes were screened and the expression of these genes was further validated in an independent data set GSE96854. We identified 864 DEGs enriched in 19 GO biological functions such as negative regulation of growth and regulation of heart contraction; 11 KEGG pathways such as mineral absorption and protein digestion and absorption. lncRNAs-mRNAs coexpressed network was constructed, including 8 modules and 177 genes. Hub lncRNAs, including LINC00619, LINC00924, LINC00261, and DRAIC, were identified. Hub mRNAs, including CYCS, CCND1, BDKRB, ITGA6, and TNNC1, were mainly enriched in cancer pathways, p53 signaling pathway, and calcium signaling pathway. The expressions of the hub mRNAs were successfully validated by another independent GSE96854 data set. Our findings indicated the hub lncRNAs, including LINC00619, LINC00924, LINC00261, and DRAIC, as well as hub mRNAs, including CYCS, CCND1, BDKRB, ITGA6, and TNNC1, might involve in the progression of HSCR, and these genes might provide new clinical biomarkers for risk evaluation of HSCR.

Epigenetic Mechanisms in Hirschsprung Disease

Hirschsprung disease (HSCR, OMIM 142623) is due to a failure of enteric precursor cells derived from neural crest (EPCs) to proliferate, migrate, survive or differentiate during Enteric Nervous System (ENS) formation. This is a complex process which requires a strict regulation that results in an ENS specific gene expression pattern. Alterations at this level lead to the onset of neurocristopathies such as HSCR. Gene expression is regulated by different mechanisms, such as DNA modifications (at the epigenetic level), transcriptional mechanisms (transcription factors, silencers, enhancers and repressors), postranscriptional mechanisms (3′UTR and ncRNA) and regulation of translation. All these mechanisms are finally implicated in cell signaling to determine the migration, proliferation, differentiation and survival processes for correct ENS development. In this review, we have performed an overview on the role of epigenetic mechanisms at transcriptional and posttranscriptional levels on these cellular events in neural crest cells (NCCs), ENS development, as well as in HSCR.

Increased miR-214 expression suppresses cell migration and proliferation in Hirschsprung disease by interacting with PLAGL2

BACKGROUND

The miR-214 has been reported to be associated with various diseases, but its involvement in the pathophysiology of Hirschsprung disease (HSCR) is almost completely unexplored.

METHODS

In our study, we conducted a series of experiments to unravel the biological role of miR-214 in the pathophysiology of HSCR. qRT-PCR and western blotting were utilized to investigate the relative expression levels of miR-214, mRNAs, and proteins of related genes in colon tissues from 20 controls without HSCR and 24 patients with HSCR. The potential biological role of miR-214 in two cell lines (SKN-SH and SH-SY5Y) was assessed using the CCK8 assay, EdU staining, transwell assay, and flow cytometry. The dual-luciferase reporter assay was used to confirm PLAGL2 as a common target gene of miR-214.

RESULTS

All results suggested that miR-214 is upregulated in HSCR tissue samples compared with controls. Additionally, we found that miR-214 could inhibit cell proliferation and migration by directly downregulating the expression of PLAGL2, and the extent of the miR-214-mediated inhibitory effects could be rescued by a PLAGL2 overexpression plasmid.

CONCLUSION

Our results revealed that miR-214 is indeed involved in the pathophysiology of HSCR and suppresses cell proliferation and migration by directly downregulating PLAGL2 in cell models.

Identification of ceRNA network based on a RNA-seq shows prognostic lncRNA biomarkers in human lung adenocarcinoma

Previous studies have emphasized the significant functions of long non-coding RNAs (lncRNAs) as competing endogenous RNAs (ceRNAs) in tumor biology. However, the functions of certain cancer lncRNAs in the lncRNA-related ceRNA network in lung adenocarcinoma (LUAD) are unknown. A systematic and integrative survey of RNA-seq data from The Cancer Genome Atlas (TCGA) was performed to identify candidate lncRNAs for the prognosis of LUAD. In total, 20,502 genes that contain 181 lncRNAs were evaluated in a cohort of 570 LUAD cases. Initially, 6,280 differentially expressed genes (fold-change >2, P<0.05) were obtained using R package, which includes 75 lncRNAs. Next, by univariate regression and multivariate Cox proportional hazards analysis, 32 genes were associated with survival in LUAD. Using these 29 mRNAs and 3 lncRNAs, a prognosis index (PI) was calculated to accurately estimate the survival in LUAD: PI=∑exp_{risk gene} × HRrisk gene. Furthermore, the 32-gene signature was an independent prognostic indicator for LUAD (HR >1; P<0.05, by multivariate analysis). Weighted gene co-expression network analysis (WGCNA) of three risk lncRNAs-FAM138B, NHEG1 and TLX1NB-was performed, based on the P-values of the associated genes, and the top 27 miRNAs that bound to these lncRNAs were predicted by Miranda as target miRNAs. Next, these target miRNAs were transferred to the TarBase, miRTarBase, miRecards and starBase v2.0 databases to obtain their target genes. According to the previous miRNA-mRNA and miRNA-lncRNA data, three lncRNA-miRNA-mRNA ceRNA networks were established, based on the 29 prognostic mRNAs, forming a regulatory network in LUAD. The present study provided insight into the lncRNA-related ceRNA network in LUAD and has identified potential diagnostic and prognostic biomarkers.

Long non-coding RNA FAL1 functions as a ceRNA to antagonize the effect of miR-637 on the down-regulation of AKT1 in Hirschsprung's disease

OBJECTIVES

Emerged evidence demonstrates that long non-coding RNAs (lncRNAs) may play quintessential regulatory roles in the cellular processes, tumourigenesis and the development of disease. Though focally amplified lncRNA on chromosome 1 (FAL1) has been identified to have crucial functions in many diseases, its biological mechanism in the development of Hirschsprung's disease (HSCR) still remains unknown.

MATERIALS AND METHODS

The expression levels of FAL1 in HSCR aganglionic tissues and matched normal specimens were detected by quantitative real-time PCR (qRT-PCR). Cell proliferation and migration were detected by Cell Counting Kit-8 (CCK-8) assay, Ethynyl-deoxyuridine (EdU) assay and transwell assay relatively. Cell cycle and apoptosis were assessed using flow cytometer analysis. Moreover, the novel targets of FAL1 were confirmed with the help of bioinformatics analysis and dual-luciferase reporter assay. Western blot assay as well as RNA immunoprecipitation (RIP) assay was conducted to investigate the potential mechanism.

RESULTS

FAL1 expression was markedly down-regulated in HSCR aganglionic tissues and decreased FAL1 expression was associated with the diagnosis of HSCR. Cell functional analyses indicated that FAL1 overexpressing notably promoted cell proliferation and migration, while down-regulation of FAL1 suppressed cell proliferation and migration. Additionally, Flow cytometry assay demonstrated that knockdown of FAL1 induced markedly cell cycle stalled in the G0/G1 phase. Furthermore, FAL1 could positively regulate AKT1 expression by competitively binding to miR-637.

CONCLUSIONS

These results illuminated that FAL1 may work as a ceRNA to modulate AKT1 expression via competitively binding to miR-637 in HSCR, suggesting that it may be clinically valuable as a biomarker of HSCR.

Erratum: LncRNA AFAP1-AS Functions as a Competing Endogenous RNA to Regulate RAP1B Expression by sponging miR-181a in the HSCR: Erratum

[This corrects the article DOI: 10.7150/ijms.18392.].