Fibulin 1, targeted by microRNA-24-3p, promotes cell proliferation and migration in vascular smooth muscle cells, contributing to the development of atherosclerosis in APOE-/- mice

Extracellular matrix (ECM) and vascular smooth muscle cells (VSMCs) are the main components of atherosclerosis (AS) plaque. VSMCs participate in plaque formation through phenotypic transformation. The complex interplay between ECM and VSMCs plays vital roles in the progression of AS throughout the disease. An in-depth investigation into the functions of ECM-related molecules in VSMC development might contribute to deciphering the complexity of AS pathogenesis. In this study, the roles and molecular mechanisms of the ECM-related molecule Fibulin-1 (FBLN1) in the development of AS and VSMCs were explored using RNA sequencing, bioinformatics analysis, and cell experiments. Furthermore, the expression of FBLN1, as determined by western blot analysis, immunohistochemistry, and real-time quantitative PCR, was significantly increased in AS vascular samples compared to normal vascular samples. Silencing the FBLN1 through AAV viral injection in mice revealed an improvement in AS. Functional analyses revealed that FBLN1 promoted VSMC proliferation, migration, and wound healing. Combined with RNA sequencing and TargetScan7.2 prediction data, 22 microRNAs (miRNAs) were found to have the potential for direct interaction with the FBLN1 3'UTR in VSMCs. Among these 22 miRNAs, it was demonstrated that microRNA-24-3p (miR-24-3p) could negatively regulate FBLN1 expression by directly binding to the FBLN1 3'UTR. Moreover, miR-24-3p inhibited cell proliferation, migration, and wound healing, and suppressed the expression of Ki67, matrix metalloproteinase-2 and -9 (MMP2/9) by targeting FBLN1 in VSMCs. Meanwhile, inhibition of FBLN1 expression could restrain VSMC phenotypic transformation. In conclusion, miR-24-3p inhibited VSMC proliferation and migration by targeting FBLN1. Additionally, multiple miRNAs with the potential to interact with the FBLN1 3'UTR were identified. These findings might deepen our understanding of ECM gene regulatory networks and the complex etiology of AS.

miR-24-3p regulation of retinol binding protein 4 in trophoblast biofunction and preeclampsia

Preeclampsia (PE) is a pregnancy-related disease and is the leading cause of overall maternal mortality and morbidity. Our previous studies have shown that the serum and placental levels of retinol-binding protein 4 (RBP4) in PE are reduced. Our previous bioinformatics analysis predicted that RBP4 is a target of the microRNA miRNA-24-3p. In this study, our database analysis also indicated that RBP4 is a miR-24-3p target. Compared with that of the normal placenta, the expression level of RBP4 in human PE placenta was significantly reduced, and miR-24-3p was highly expressed. In HTR-8/SVneo cells, transfection of exogenous miR-24-3p reduced RBP4 expression. A dual-luciferase reporter assay validated RBP4 as a direct target of miR-24-3p, indicating that it directly binds to the 3'-untranslated region of RBP4. This binding was reversed by a mutation in the microRNA-binding site. Transwell invasion experiments and CCK8 assay showed that inhibitory effect of miR-24-3p reduced RBP4 mediated HTR-8/SVneo cell invasion and proliferation. These data provide a new overarching perspective on the physiological role played by miR-24-3p in regulating RBP4 during trophoblast dysfunction and PE development.

Long noncoding RNA PVT1 accelerates the growth of placental trophoblasts in preeclampsia through the microRNA-24-3p/HSD11B2 axis

Long noncoding RNA plasmacytoma variant translocation 1 (PVT1) is essential for the maintenance of normal functions of trophoblasts in preeclampsia (PE). This study aims to decipher the concrete mechanism of PVT1 with the microRNA-24-3p/Type-2 11β-hydroxysteroid dehydrogenase (miR-24-3p/HSD11B2) axis in PE. PVT1, miR-24-3p, and HSD11B2 expression levels in normal placental tissues and PE placental tissues were defined. HTR-8/SVneo cells were transfected to determine the effects of PVT1, miR-24-3p, and HSD11B2 on the growth of HTR-8/SVneo cells. The relationships among PVT1/miR-24-3p/HSD11B2 in HTR-8/SVneo cells were identified. PVT1 and HSD11B2 were downregulated, while miR-24-3p was upregulated in the placenta of PE. Upregulated/downregulated PVT1 promoted/impeded the growth of human placental trophoblast (HTR-8/SVneo) cells in PE. Restored/knocked down miR-24-3p impeded/enhanced the growth of HTR-8/SVneo cells in PE. PVT1 inhibited miR-24-3p to mediate HSD11B2. PVT1 sponges miR-24-3p to regulate HSD11B2; thereby, the growth of placental trophoblasts is promoted in PE.

Cancer-associated fibroblast-derived exosomal microRNA-24-3p enhances colon cancer cell resistance to MTX by down-regulating CDX2/HEPH axis

MicroRNA‐24‐3p (miR‐24‐3p) has been implicated as a key promoter of chemotherapy resistance in numerous cancers. Meanwhile, cancer‐associated fibroblasts (CAFs) can secret exosomes to transfer miRNAs, which mediate tumour development. However, little is known regarding the molecular mechanism of CAF‐derived exosomal miR‐24‐3p in colon cancer (CC). Hence, this study intended to characterize the functional relevance of CAF‐derived exosomal miR‐24‐3p in CC cell resistance to methotrexate (MTX). We identified differentially expressed HEPH, CDX2 and miR‐24‐3p in CC through bioinformatics analyses, and validated their expression in CC tissues and cells. The relationship among HEPH, CDX2 and miR‐24‐3p was verified using ChIP and dual‐luciferase reporter gene assays. Exosomes were isolated from miR‐24‐3p inhibitor–treated CAFs (CAFs‐exo/miR‐24‐3p inhibitor), which were used in combination with gain‐of‐function and loss‐of‐function experiments and MTX treatment. CCK‐8, flow cytometry and colony formation assays were conducted to determine cell viability, apoptosis and colony formation, respectively. Based on the findings, CC tissues and cells presented with high expression of miR‐24‐3p and low expression of HEPH and CDX2. CDX2 was a target gene of miR‐24‐3p and could up‐regulate HEPH. Under MTX treatment, overexpressed CDX2 or HEPH and down‐regulated miR‐24‐3p reduced cell viability and colony formation and elevated cell apoptosis. Furthermore, miR‐24‐3p was transferred into CC cells via CAF‐derived exosomes. CAF‐derived exosomal miR‐24‐3p inhibitor diminished cell viability and colony formation and increased cell apoptosis in vitro and inhibited tumour growth in vivo under MTX treatment. Altogether, CAF‐derived exosomal miR‐24‐3p accelerated resistance of CC cells to MTX by down‐regulating CDX2/HEPH axis.

Knockdown of lncRNA NEAT1 expression inhibits cell migration, invasion and EMT by regulating the miR-24-3p/LRG1 axis in retinoblastoma cells

Retinoblastoma (RB) is the most common primary intraocular cancer type that occurs during retinal development in childhood. Previous studies have reported that long non-coding RNAs (lncRNAs) are involved in the development of RB. Therefore, the aim of the present study was to investigate the effects and underlying regulatory mechanisms of nuclear paraspeckle assembly transcript 1 (NEAT1) in RB. The expression levels of NEAT1, microRNA (miR)-24-3p and leucine-rich-α-2-glycoprotein (LRG1) were detected using reverse transcription-quantitative PCR (RT-qPCR). Moreover, the protein expression levels of LRG1, matrix metalloproteinase 9, N-cadherin and E-cadherin were detected via western blotting. Furthermore, cell migration and invasion abilities were evaluated via Transwell assays. The targeting relationships between miR-24-3p and NEAT1 or LRG1 were predicted using online software and confirmed via dual-luciferase reporter assay. In the present study, NEAT1 and LRG1 were upregulated, and miR-24-3p was downregulated in RB tissues and cells compared with the corresponding healthy tissues and cells. Moreover, miR-24-3p was identified as a target of NEAT and LRG1 was demonstrated to be a direct target gene of miR-24-3p. Knockdown of NEAT1 or LRG1 significantly suppressed RB cell migration and invasion ability, while the effects were reversed by an miR-24-3p inhibitor. In addition, the downregulation of LRG1 caused by miR-24-3p was restored following the overexpression of NEAT1 in RB cells. It was also demonstrated that NEAT1 knockdown inhibited the epithelial-to-mesenchymal transition (EMT) pathway by inhibiting the expression of LRG via targeting miR-24-3p. In conclusion, the present results suggest that silencing of NEAT1 suppresses cell migration, invasion and the EMT process by downregulating LRG1 expression via sponging miR-24-3p in RB, thus indicating that NEAT1 may be a potential candidate for RB treatment.

MicroRNA-24-3p inhibition prevents cell growth of vascular smooth muscle cells by targeting Bcl-2-like protein 11

Numerous reports have shown that dysfunction of vascular smooth muscle cells (VSMCs) serves a critical function in the development of cardiovascular disease, including coronary heart disease (CHD). microRNAs (miRNAs/miRs) have been reported to play important roles in regulating the function of VSMCs. The present study aimed to determine the role of miR-24-3p in VSMCs and to uncover the underlying mechanism. The expression of miR-24-3p in the peripheral blood samples of CHD patients was measured by reverse transcription-quantitative (RT-q)PCR. It was found that the level of miR-24-3p in the peripheral blood of patients with CHD was significantly upregulated compared with that in healthy controls. A dual luciferase reporter assay was performed to determine whether Bcl-2-like protein 11 (Bcl-2L11) was a target gene of miR-24-3p, and it was identified that Bcl-2L11 was a direct target of miR-24-3p. The mRNA level and protein expression of Bcl-2L11 in the peripheral blood of patients with CHD were measured by RT-qPCR and western blotting, respectively. The findings suggested that Bcl-2L11 was downregulated in the peripheral blood of patients with CHD. In addition, it was found that downregulation of miR-24-3p suppressed VSMC proliferation and promoted VSMC apoptosis, while the effects of the miR-24-3p inhibitor on cell viability and apoptosis were reversed by Bcl-2L11-small interfering (si)RNA. Additionally, downregulation of miR-24-3p increased the levels of Bcl-2L11, caspase-3 and Bax, and decreased Bcl-2 expression in VSMCs; these changes were abolished by Bcl-2L11-siRNA. In conclusion, the aforementioned results indicated that miR-24-3p was an important regulator in VSMC proliferation and apoptosis by targeting Bcl-2L11, which suggested that miR-24-3p might be a potential therapeutic target for the treatment of CHD.

MicroRNA-24-3p regulates Hodgkin's lymphoma cell proliferation, migration and invasion by targeting DEDD

Hodgkin's lymphoma (HL) is a common hematologic tumor, and the incidence is increasing. At present, it is considered that miRNAs are closely related to HL. Substantial attention has been paid to the effects of miRNA on the pathophysiological process of HL. This study was focused on the potential role of miR-24-3p in HL by targeting DEDD. The reverse transcription-quantitative PCR (RT-qPCR) results demonstrated that miR-24-3p expression was highly elevated and DEDD expression reduced inversely in HL tissues compared to adjacent tissues. According to the results of CKK-8 assays, miR-24-3p was able to accelerate HL cell proliferation. In addition, the results of the Transwell assays also indicated that miR-24-3p promoted the invasion and migration abilities of HL cells. Moreover, the results demonstrated that miR-24-3p inhibited DEDD expression. Hence, the present study revealed that miR-24-3p could accelerate HL development through inhibiting DEDD.