miR‐126‐5p enhances radiosensitivity of lung adenocarcinoma cells by inhibiting EZH2 via the KLF2/BIRC axis

Radiotherapy is a common method for the treatment of lung adenocarcinoma, but it often fails due to the relative non‐susceptibility of lung adenocarcinoma cells to radiation. We aimed to discuss the related mechanisms by which miR‐126‐5p might mediate radiosensitivity of lung adenocarcinoma cells. The binding affinity between miR‐126‐5p and EZH2 and between KLF2 and BIRC5 was identified using multiple assays. A549 and H1650 cells treated with X‐ray were transfected with miR‐126‐5p mimic/inhibitor, oe‐EZH2, or si‐KLF2 to detect cell biological functions and radiosensitivity. Finally, lung adenocarcinoma nude mouse models were established. miR‐126‐5p and KLF2 were poorly expressed, while EZH2 and BIRC5 were upregulated in lung adenocarcinoma tissues and cells. miR‐126‐5p targeted EZH2 to promote the KLF2 expression so as to inhibit BIRC5 activation. Both in vitro and in vivo experiments verified that elevated miR‐126‐5p inhibited cell migration and promoted apoptosis to enhance the sensitivity of lung adenocarcinoma cells to radiotherapy via the EZH2/KLF2/BIRC5 axis. Collectively, miR‐126‐5p downregulated EZH2 to facilitate the sensitivity of lung adenocarcinoma cells to radiotherapy via KLF2/BIRC5.     

LncRNA HCG11/miR‐26b‐5p/QKI5 feedback loop reversed high glucose‐induced proliferation and angiogenesis inhibition of HUVECs

Acute coronary syndrome caused by the rupture of atherosclerotic plaques is one of the primary causes of cerebrovascular and cardiovascular events. Neovascularization within the plaque is closely associated with its stability. Long non‐coding RNA (lncRNA) serves a crucial role in regulating vascular endothelial cells (VECs) proliferation and angiogenesis. In this study, we identified lncRNA HCG11, which is highly expressed in patients with vulnerable plaque compared with stable plaque. Then, functional experiments showed that HCG11 reversed high glucose‐induced vascular endothelial injury through increased cell proliferation and tube formation. Meanwhile, vascular‐related RNA‐binding protein QKI5 was greatly activated. Luciferase reporter assays and RNA‐binding protein immunoprecipitation (RIP) assays verified interaction between them. Interestingly, HCG11 can also positively regulated by QKI5. Bioinformatics analysis and luciferase reporter assays showed HCG11 can worked as a competing endogenous RNA by sponging miR‐26b‐5p, and QKI5 was speculated as the target of miR‐26b‐5p. Taken together, our findings revered that the feedback loop of lncRNA HCG11/miR‐26b‐5p/QKI‐5 played a vital role in the physiological function of HUVECs, and this also provide a potential target for therapeutic strategies of As.     

circ‐AKT3 aggravates renal ischaemia‐reperfusion injury via regulating miR‐144‐5p /Wnt/β‐catenin pathway and oxidative stress

Renal ischaemia‐reperfusion (RI/R) injury is one major pathological state of acute kidney injury (AKI) with a mortality rate ranking 50% to 80%. MiR‐144‐5p acts as a molecular trigger in various diseases. We presumed that miR‐144‐5p might be involved RI/R injury progression. We found that RI/R injury decreased miR‐144‐5p expression in rat models. MiR‐144‐5p downregulation promoted cell apoptosis rate and activated Wnt/β‐catenin signal in RI/R injury rats. By performing bioinformatic analysis, RIP, RNA pull‐down, luciferase reporter experiments, we found that circ‐AKT3 sponged to miR‐144‐5p and decreased its expression in RI/R injury rats. Moreover, we found that circ‐AKT3 promoted cell apoptosis rate and activated Wnt/β‐catenin signal, and miR‐144‐5p mimic reversed the promotive effect of circ‐AKT3 in rat models. We also found that circ‐AKT3 increased the oxidative stress level in rat models. In conclusion, our study suggests that the circAKT3 is involved RI/R injury progression through regulating miR‐144‐5p/Wnt/β‐catenin pathway and oxidative stress.     

Down‐regulated LINC00115 inhibits prostate cancer cell proliferation and invasion via targeting miR‐212‐5p/FZD5/Wnt/β‐catenin axis

Prostate cancer is the second most frequent malignancy in men worldwide, and its incidence is increasing. Therefore, it is urgently required to clarify the underlying mechanisms of prostate cancer. Although the long non‐coding RNA LINC00115 was identified as an oncogene in several cancers, the expression and function of LINC00115 in prostate cancer have not been explored. Our results showed that LINC00115 was significantly up‐regulated in prostate cancer tissues, which was significantly associated with a poor prognosis for prostate cancer patients. Functional studies showed that knockdown LINC00115 inhibited cell proliferation and invasion. In addition, LINC00115 served as a competing endogenous RNA (ceRNA) through sponging miR‐212‐5p to release Frizzled Family Receptor 5 (FZD5) expression. The expression of miR‐212‐5p was noticeably low in tumour tissues, and FZD5 expression level was down‐regulated with the knockdown of LINC00115. Knockdown LINC00115 inhibited the Wnt/β‑catenin signalling pathway by inhibiting the expression of FZD5. Rescue experiments further showed that LINC00115 inhibits prostate cancer cell proliferation and invasion via targeting miR‐212‐5p/ FZD5/ Wnt/β‐catenin axis. The present study provided clues that LINC00115 may be a promising novel therapeutic target for prostate cancer patients.     

Knockdown of circular RNA VANGL1 inhibits TGF‐β‐induced epithelial‐mesenchymal transition in melanoma cells by sponging miR‐150‐5p

Melanoma is one of the most aggressive and life‐threatening skin cancers, and in this research, we aimed to explore the functional role of circular RNA VANGL1 (circVANGL1) in melanoma progression. The expression levels of circVANGL1 were observed to be significantly increased in clinical melanoma tissues and cell lines. Moreover, circVANGL1 knockdown suppressed, while circVANGL1 overexpression promoted the proliferation, migration and invasion abilities of melanoma cells. Further investigations confirmed the direct binding relation between circVANGL1 and miR‐150‐5p in melanoma, and restoration of miR‐150‐5p blocked the effects of circVANGL1 overexpression in melanoma cells. We further found that circVANGL1 was up‐regulated by TGF‐β treatment, and the enhanced EMT of TGF‐β‐treated melanoma cells was blocked by circVANGL1 knockdown. In conclusion, these results indicated that circVANGL1 might serve as a promising therapeutic target for melanoma.     

circRNA 001306 enhances hepatocellular carcinoma growth by up‐regulating CDK16 expression via sponging miR‐584‐5p

Circular RNAs (circRNAs) have been demonstrated to play important roles in cancer progress. However, the roles in hepatocellular carcinoma (HCC) are still unclear. Here, we found has_circRNA_001306 (circ_1306) was up‐regulated in HCC tissues and cell lines. Knockdown the expression circ_1306 significantly suppressed HCC cell proliferation and induced the cell apoptosis in vitro and in vivo. Furthermore, we identified circ_1306 could up‐regulate the expression of CDK16 by sponging miR‐584‐5p. The expression of miR‐584‐5p was decreased, and the expression of CDK16 was increased in HCC tissues and cell lines. Meanwhile, either knockdown of miR‐584‐5p or overexpression of CDK16 could suppress the HCC cell proliferation. In vivo, overexpression of miR‐584‐5p or knockdown of circ_1306 could inhibit the expression of CDK16, and suppress tumour growth. Altogether, our findings suggested that circ_1306 could promoter HCC progress by miR‐584‐5p/CDK16 axis, which provided a novel marker for HCC diagnosis and treatment.     

METTL3‐mediated maturation of miR‐589‐5p promotes the malignant development of liver cancer

MiR‐589‐5p could promote liver cancer, but the specific mechanisms are largely unknown. This study examined the role and mechanisms of miR‐589‐5p in liver cancer. The expressions of miR‐589‐5p, METTL3 and m6A in liver cancers were determined by RT‐qPCR. The relationship between miR‐589‐5p and METTL3‐mediated m6A methylation was examined by m6A RNA immunoprecipitation. After transfection, the viability, migration, invasion and expressions of METTL3 and miR‐589‐5p in liver cancer cells were detected by CCK‐8, wound‐healing, transwell and RT‐qPCR. After the xenograft tumour was established in mice, the tumour volume was determined and the expressions of METTL3, miR‐589‐5p, MMP‐2, TIMP‐2, E‐cadherin, N‐cadherin and Vimentin in tumour tissue were detected by RT‐qPCR and Western blotting. In vitro study showed that miR‐589‐5p and METTL3 were highly expressed in liver cancer. METTL3 was positively correlated with miR‐589‐5p. METTL3 up‐regulated the expression of miR‐589‐5p and promoted the maturation of miR‐589‐5p. Overexpressed miR‐589‐5p and METTL3 promoted the viability, migration and invasion of liver cancer cells, while the effects of silencing miR‐589‐5p and METTL3 on the cells were the opposite. The effects of METTL3 overexpression and silencing were reversed by miR‐589‐5p inhibitor and mimic, respectively. In vivo study showed that METLL3 silencing inhibited the growth of xenograft tumour and the expressions of METTL3, MMP‐2, N‐cadherin and Vimentin, promoted the expressions of TIMP‐2 and E‐cadherin, while miR‐589‐5p mimic caused the opposite results and further reversed the effects of METLL3 silencing. In summary, this study found that METTL3‐mediated maturation of miR‐589‐5p promoted the malignant development of liver cancer.     

CircSAMD4A aggravates H/R‐induced cardiomyocyte apoptosis and inflammatory response by sponging miR‐138‐5p

Hypoxia/reoxygenation (H/R)‐induced myocardial cell injury is the main cause of acute myocardial infarction (AMI). Many proofs show that circular RNA plays an important role in the development of AMI. The purpose of this study was to investigate the role of circSAMD4A in H/R‐induced myocardial injury. The levels of circular SAMD4A (circSAMD4A) were detected in the heart tissues of AMI mice and H/R‐induced H9C2 cells, and the circSAMD4A was suppressed in AMI mice and H/R‐induced H9C2 cells to investigate its’ function in AMI. The levels of circSAMD4A and miR‐138‐5p were detected by real‐time quantitative PCR, and MTT assay was used to detect cell viability. TUNEL analysis and Annexin V‐FITC were used to determine apoptosis. The expression of Bcl‐2 and Bax proteins was detected by Western blot. IL‐1β, TNF‐α and IL‐6 were detected by ELISA kits. The study found that the levels of circSAMD4A were up‐regulated after H/R induction and inhibition of circSAMD4A expression would reduce the H/R‐induced apoptosis and inflammation. MiR‐138‐5p was down‐regulated in H/R‐induced H9C2 cells. circSAMD4A was a targeted regulator of miR‐138‐5p. CircSAMD4A inhibited the expression of miR‐138‐5p to promote H/R‐induced myocardial cell injury in vitro and vivo. In conclusion, CircSAMD4A can sponge miR‐138‐5p to promote H/R‐induced apoptosis and inflammatory response.     

LOXL1‐AS1 communicating with TIAR modulates vasculogenic mimicry in glioma via regulation of the miR‐374b‐5p/MMP14 axis

At present, growing evidence indicates that long non‐coding RNAs (lncRNAs) participate in the progression of glioma. The function of LOXL1‐AS1 in vasculogenic mimicry (VM) in glioma remains unclear. First, the expressions of TIAR, the lncRNA LOXL1‐AS1, miR‐374b‐5p and MMP14 were examined by qRT‐PCR and Western blot in both, glioma tissues and glioma cell lines. Proliferation, migration, invasion and tube formation assays were conducted to evaluate the roles of TIAR, LOXL1‐AS1, miR‐374b‐5p and MMP14 in malignant cellular behaviours in glioma cells. A nude mouse xenograft model and dual staining for CD34 and PAS were used to assess whether VM was affected by TIAR, LOXL1‐AS1 or miR‐374b‐5p in vivo. In this study, low levels of TIAR and high levels of LOXL1‐AS1 were found in glioma cells and tissues. TIAR downregulated the expression of LOXL1‐AS1 by destabilizing it. LOXL1‐AS1 acted like a miRNA sponge towards miR‐374b‐5p so that downregulation of the former greatly inhibited cell proliferation, migration, invasion and VM. Additionally, miR‐374b‐5p overexpression repressed malignant biological behaviours and VM in glioma by modifying MMP14. In summary, we demonstrated that TIAR combined with LOXL1‐AS1 modulates VM in glioma via the miR‐374b‐5p/MMP14 axis, revealing novel targets for glioma therapy.     

Bone marrow macrophage‐derived exosomal miR‐143‐5p contributes to insulin resistance in hepatocytes by repressing MKP5

ObjectiveIn this study, we aim to explore the role of bone marrow macrophage‐derived exosomes in hepatic insulin resistance, investigate the substance in exosomes that regulates hepatic insulin signalling pathways, reveal the specific molecular mechanisms involved in hepatic insulin resistance and further explore the role of exosomes in type 2 diabetes.Materials and methodsHigh‐fat diet (HFD)‐fed mice were used as obesity‐induced hepatic insulin resistance model, exosomes were isolated from BMMs which were extracted from HFD‐fed mice by ultracentrifugation. Exosomes were analysed the spectral changes of microRNA expression using a microRNA array. The activation of the insulin signalling pathway and the level of glycogenesis were examined in hepatocytes after transfected with miR‐143‐5p mimics. Luciferase assay and western blot were used to assess the target of miR‐143‐5p.ResultsBMMs from HFD‐fed mice were polarized towards M1, and miR‐143‐5p was significantly upregulated in exosomes of BMMs from HFD‐fed mice. Overexpression of miR‐143‐5p in Hep1‐6 cells led to decreased phosphorylation of AKT and GSK and glycogen synthesis. Dual‐luciferase reporter assay and western blot demonstrated that mitogen‐activated protein kinase phosphatase‐5 (Mkp5, also known as Dusp10) was the target gene of miR‐143‐5p. Moreover, the overexpression of MKP5 could rescue the insulin resistance induced by transfection miR‐143‐5p mimics in Hep1‐6.ConclusionBone marrow macrophage‐derived exosomal miR‐143‐5p induces insulin resistance in hepatocytes through repressing MKP5.     

Circ_0067835 sponges miR‐324‐5p to induce HMGA1 expression in endometrial carcinoma cells

Endometrial cancer is a common gynaecological malignant tumour among women across the world. Circular RNAs (circRNAs) are a novel kind of non‐coding RNAs, and they can play a crucial role in multiple cancers. Nevertheless, the mechanisms of circRNAs in regulating gene expression in endometrial cancer are still unclear. Here, our work sought to focus on the role that circ_0067835 exert in progression and development of endometrial cancer cells. We observed circ_0067835 was markedly elevated in endometrial cancer. Then, changes in endometrial cancer cell (RL95‐2 and HEC‐1B) function were determined after circ_0067835 knockdown. Loss‐of‐functional assays revealed that circ_0067835 down‐regulation significantly repressed RL95‐1 and HEC‐1B cell proliferation, migration and invasion. Bioinformatics analysis, luciferase reporter experiment and RNA pull‐down assay were employed to predict and validate circ_0067835 can bind to miR‐324‐5p. Increase in miR‐324‐5p remarkably depressed the proliferation, migration and invasion of endometrial cancer cells via inhibiting high mobility group A1 (HMGA1). HMGA1 is identified as a vital prognostic biomarker in endometrial cancer. Currently, we reported circ_0067835 was positively correlated with HMGA1 in endometrial cancer. We implied that circ_0067835 was capable of sponging miR‐324‐5p and inducing its downstream target HMGA1 in vitro and in vivo. In conclusion, circ_0067835 can compete with miR‐324‐5p, resulting in HMGA1 up‐regulation, and therefore induce the development of endometrial cancer.     

CircHivep2 contributes to microglia activation and inflammation via miR‐181a‐5p/SOCS2 signalling in mice with kainic acid‐induced epileptic seizures

Epilepsy is a chronic brain disease characterized by recurrent seizures. Circular RNA (circRNA) is a novel family of endogenous non‐coding RNAs that have been proposed to regulate gene expression. However, there is a lack of data on the role of circRNA in epilepsy. In this study, the circRNA profiles were evaluated by microarray analysis. In total, 627 circRNAs were up‐regulated, whereas 892 were down‐regulated in the hippocampus in mice with kainic acid (KA)‐induced epileptic seizures compared with control. The expression of circHivep2 was significantly down‐regulated in hippocampus tissues of mice with KA‐induced epileptic seizures and BV‐2 microglia cells upon KA treatment. Bioinformatics analysis predicted that circHivep2 interacts with miR‐181a‐5p to regulate SOCS2 expression, which was validated using a dual‐luciferase reporter assay. Moreover, overexpression of circHivep2 significantly inhibited KA‐induced microglial activation and the expression of inflammatory factors in vitro, which was blocked by miR‐181a‐5p, whereas circHivep2 knockdown further induced microglia cell activation and the release of pro‐inflammatory proteins in BV‐2 microglia cells after KA treatment. The application of circHivep2+ exosomes derived from adipose‐derived stem cells (ADSCs) exerted significant beneficial effects on the behavioural seizure scores of mice with KA‐induced epilepsy compared to control exosomes. The circHivep2+ exosomes also inhibited microglial activation, the expression of inflammatory factors, and the miR‐181a‐5p/SOCS2 axis in vivo. Our results suggest that circHivep2 regulates microglia activation in the progression of epilepsy by interfering with miR‐181a‐5p to promote SOCS2 expression, indicating that circHivep2 may serve as a therapeutic tool to prevent the development of epilepsy.     

Hsa_circ_0003945 promotes progression of hepatocellular carcinoma by mediating miR‐34c‐5p/LGR4/β‐catenin axis activity

Accumulating evidence suggests that circular RNAs (circRNAs) play essential roles in regulating cancer progression, but many circRNAs in hepatocellular carcinoma (HCC) remain unknown. Dysregulated circRNAs in HCC were identified through bioinformatics analysis of Gene Expression Omnibus data sets. Quantitative real‐time PCR (qRT‐PCR), Sanger sequencing, RNase R digestion and actinomycin D treatment were conducted to confirm the characterization of circRNAs. CCK‐8, wound‐healing and Transwell assays were performed to assess the functional roles of Hsa_circ_0003945 (Circ_0003945) in HCC cell lines. Subcellular fractionation and fluorescence in situ hybridization (FISH) were performed to locate Circ_0003945 in HCC cells. Dual‐luciferase reporter assay was executed to verify the binding of Circ_0003945 to microRNAs (miRNAs) or the miRNAs to their target genes. In this study, we found that Circ_0003945 was upregulated in HCC tissue, and higher Circ_0003945 expression was positively correlated with tumour size and tumour stage. Furthermore, high plasma levels of circulating Circ_0003945 were confirmed in HCC patients compared with those in non‐HCC groups. The functional experiments revealed that overexpression or knockdown of Circ_0003945 promoted or attenuated tumour growth and migration, respectively. Mechanistically, Circ_0003945 might exert as a miR‐34c‐5p sponge to upregulate the expression of leucine‐rich repeat‐containing G protein‐coupled receptor 4 (LGR4), activating the β‐catenin pathway, and finally facilitating HCC progression. Additionally, a β‐catenin activator could reverse the effect of Circ_0003945 knockdown. In conclusion, Circ_0003945 exerts a tumour‐promoting role in HCC cells by regulating the miR‐34c‐5p/LGR4/β‐catenin axis, which may be a potential target for HCC therapy.     

MiR‐223‐3p inhibits rTp17‐induced inflammasome activation and pyroptosis by targeting NLRP3

The incidence of syphilis caused by Treponema pallidum subsp pallidum (T pallidum) infection is accompanied by inflammatory injuries of vascular endothelial cells. Studies have revealed that T pallidum infection could induce inflammasome activation and pyroptosis in macrophages. MicroRNA‐223‐3p (miR‐223‐3p) was reported to be a negative regulator in inflammatory diseases. The present study aimed to explore whether miR‐223‐3p regulates T pallidum‐induced inflammasome activation and pyroptosis in vascular endothelial cells, and determine the mechanisms which underlie this process. MiR‐223‐3p levels in syphilis and control samples were determined. The biological function of miR‐223‐3p in the NLRP3 inflammasome and pyroptosis was evaluated in T pallidum‐infected human umbilical vein endothelial cells (HUVECs). We observed a dramatic decrease in miR‐223‐3p levels in syphilis patients (n = 20) when compared to healthy controls (n = 20). Moreover, miR‐223‐3p showed a notable inhibitory effect on recombinant Tp17 (rTP17)‐induced caspase‐1 activation, resulting in decrease in IL‐1β production and pyroptosis, which was accompanied by the release of lactate dehydrogenase (LDH) in HUVECs. Additionally, the dual‐luciferase assay confirmed that NLRP3 is a direct target of miR‐223‐3p. Moreover, NLRP3 overexpression or knockdown largely blocked the effects of miR‐223‐3p on T pallidum‐induced inflammasome activation and pyroptosis in HUVECs. Most importantly, a notable negative correlation was observed between miR‐223‐3p and NLRP3, caspase‐1, and IL‐1β, respectively, in the serum of syphilis patients and healthy controls. Taken together, our results reveal that miR‐223‐3p targets NLRP3 to suppress inflammasome activation and pyroptosis in T pallidum‐infected endothelial cells, implying that miR‐223‐3p could be a potential target for syphilis patients.     

Circular RNA circ_0002137 regulated the progression of osteosarcoma through regulating miR‐433‐3p/ IGF1R axis

Current clinical treatment targeting osteosarcoma (OS) are limited for OS patients with pulmonary metastasis or relapse, which led to high mortality (70%‐85%) for advanced osteosarcoma patients. Although ongoing efforts have been made to illustrate the mechanisms of tumorigenesis and progression in OS; however, it was far for us to learn a comprehensive molecular mechanism implies in OS development. In our study, we implicated a circRNA hsa_circ_0002137, which was higher expressed in osteosarcoma tumours compared with paracancerous tissue. The dysregulated expression pattern was also found in osteosarcoma cell lines. The role of circ_0002137 was explored via down‐ or up‐regulated experiments. It was proved that down‐regulation of circ_0002137 suppressed the progress of OS, including cell invasion, cell cycle and cell apoptosis. Furthermore, the correlation between circ_0002137 and miR‐433‐3p was predicted using bioinformatic tools and verified utilizing RNA pull‐down assay and luciferase reporter assay. Interestingly, we found that the inhibitory effect of circ_0002137 on OS was dependent of insulin‐like growth factor‐1 receptor (IGF1R). In conclusion, it was demonstrated that circ_0002137 could restrain the progression of OS through regulating miR‐433‐3p/IGF1R axis, providing a comprehensive landscape of circ_0002137 in the generation and development of OS.     

Circ_0075829 facilitates the progression of pancreatic carcinoma by sponging miR‐1287‐5p and activating LAMTOR3 signalling

Pancreatic cancer (PC) is a leading cause of cancer‐related mortality globally. Though increasing evidence has demonstrated that circular RNAs (circRNAs) are linked to the development and progression of cancers, the biological functions of circRNAs in PC remain largely unexplored so far. Based on previous studies, Hsc_circ_0075829 (circ_0075829) was screened out and then further identified in PC clinical specimens and cell lines by real‐time PCR. After the stability tests, a series of in vitro and in vivo functional experiments were performed to investigate the role of circ_0075829 in PC development. Furthermore, fluorescent in situ hybridization (FISH), bioinformatics tools, dual‐luciferase assays and rescue experiments were conducted to clarify the regulatory mechanisms of circ_0075829 in SW1990 and BxPC‐3 cells. Compared with paracancerous tissues, the expression of circ_0075829 was increased in PC tissues, which was positively correlated with the clinical features of PC. Knockdown of circ_0075829 significantly suppressed the proliferative, migratory and invasive rates of SW1990 and BxPC‐3 cells both in vitro and in vivo. Bioinformatics analysis and dual‐luciferase reporter gene assay indicated that circ_0075829 could bind to miR‐1287‐5p. Mechanism research and rescue experiments demonstrated that circ_0075829 could regulate the LAMTOR3/p‐ERK signalling pathway via sponging miR‐1287‐5p in PC cell lines. Our data reveal that the circ_0075829 could facilitate the proliferation and metastasis of PC through circ_0075829/miR‐1287‐5p/LAMTOR3 axis.     

Exosomal miR‐532‐5p induced by long‐term exercise rescues blood–brain barrier function in 5XFAD mice via downregulation of EPHA4

The breakdown of the blood–brain barrier, which develops early in Alzheimer''s disease (AD), contributes to cognitive impairment. Exercise not only reduces the risk factors for AD but also confers direct protection against cognitive decline. However, the exact molecular mechanisms remain elusive, particularly whether exercise can liberate the function of the blood–brain barrier. Here, we demonstrate that long‐term exercise promotes the clearance of brain amyloid‐β by improving the function of the blood–brain barrier in 5XFAD mice. Significantly, treating primary brain pericytes or endothelial cells with exosomes isolated from the brain of exercised 5XFAD mice improves cell proliferation and upregulates PDGFRβ, ZO‐1, and claudin‐5. Moreover, exosomes isolated from exercised mice exhibit significant changes in miR‐532‐5p. Administration or transfection of miR‐532‐5p to sedentary mice or primary brain pericytes and endothelial cells reproduces the improvement of blood–brain barrier function. Exosomal miR‐532‐5p targets EPHA4, and accordingly, expression of EphA4 is decreased in exercised mice and miR‐532‐5p overexpressed mice. A specific siRNA targeting EPHA4 recapitulates the effects on blood–brain barrier‐associated cells observed in exercised 5XFAD mice. Overall, our findings suggest that exosomes released by the brain contain a specific miRNA that is altered by exercise and has an impact on blood–brain barrier function in AD.     

A circular intronic RNA ciPVT1 delays endothelial cell senescence by regulating the miR‐24‐3p/CDK4/pRb axis

Circular RNAs (circRNAs) have been established to be involved in numerous processes in the human genome, but their function in vascular aging remains largely unknown. In this study, we aimed to characterize and analyze the function of a circular intronic RNA, ciPVT1, in endothelial cell senescence. We observed significant downregulation of ciPVT1 in senescent endothelial cells. In proliferating endothelial cells, ciPVT1 knockdown induced a premature senescence‐like phenotype, inhibited proliferation, and led to an impairment in angiogenesis. An in vivo angiogenic plug assay revealed that ciPVT1 silencing significantly inhibited endothelial tube formation and decreased hemoglobin content. Conversely, overexpression of ciPVT1 in old endothelial cells delayed senescence, promoted proliferation, and increased angiogenic activity. Mechanistic studies revealed that ciPVT1 can sponge miR‐24‐3p to upregulate the expression of CDK4, resulting in enhanced Rb phosphorylation. Moreover, enforced expression of ciPVT1 reversed the senescence induction effect of miR‐24‐3p in endothelial cells. In summary, the present study reveals a pivotal role for ciPVT1 in regulating endothelial cell senescence and may have important implications in the search of strategies to counteract the development of age‐associated vascular pathologies.     

METTL3/N6‐methyladenosine/ miR‐21‐5p promotes obstructive renal fibrosis by regulating inflammation through SPRY1/ERK/NF‐κB pathway activation

Renal fibrosis induced by urinary tract obstruction is a common clinical occurrence; however, effective treatment is lacking, and a deeper understanding of the mechanism of renal fibrosis is needed. Previous studies have revealed that miR‐21 impacts liver and lung fibrosis progression by activating the SPRY1/ERK/NF‐kB signalling pathway. However, whether miR‐21 mediates obstructive renal fibrosis through the same signalling pathway has not been determined. Additionally, studies have shown that N6‐methyladenosine (m⁶A) modification‐dependent primary microRNA (pri‐microRNA) processing is essential for maturation of microRNAs, but its role in the maturation of miR‐21 in obstructive renal fibrosis has not yet been investigated in detail. To address these issues, we employed a mouse model of unilateral ureteral obstruction (UUO) in which the left ureters were ligated for 3, 7 and 14 days to simulate the fibrotic process. In vitro, human renal proximal tubular epithelial (HK‐2) cells were transfected with plasmids containing the corresponding sequence of METTL3, miR‐21‐5p mimic or miR‐21‐5p inhibitor. We found that the levels of miR‐21‐5p and m⁶A modification in the UUO model groups increased significantly, and as predicted, the SPRY1/ERK/NF‐kB pathway was activated by miR‐21‐5p, confirming that miR‐21‐5p plays an important role in obstructive renal fibrosis by enhancing inflammation. METTL3 was found to play a major catalytic role in m⁶A modification in UUO mice and drove obstructive renal fibrosis development by promoting miR‐21‐5p maturation. Our research is the first to demonstrate the role of the METTL3‐m⁶A‐miR‐21‐5p‐SPRY1/ERK/NF‐kB axis in obstructive renal fibrosis and provides a deeper understanding of renal fibrosis.