MiRNA-200b Regulates RMP7-Induced Increases in Blood-Tumor Barrier Permeability by Targeting RhoA and ROCKII

Non-coding RNAs in the regulation of blood–brain barrier functions in central nervous system disorders

The blood–brain barrier (BBB) is an essential component of the neurovascular unit that controls the exchanges of various biological substances between the blood and the brain. BBB damage is a common feature of different central nervous systems (CNS) disorders and plays a vital role in the pathogenesis of the diseases. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNA (lncRNAs), and circular RNAs (circRNAs), are important regulatory RNA molecules that are involved in almost all cellular processes in normal development and various diseases, including CNS diseases. Cumulative evidences have demonstrated ncRNA regulation of BBB functions in different CNS diseases. In this review, we have summarized the miRNAs, lncRNAs, and circRNAs that can be served as diagnostic and prognostic biomarkers for BBB injuries, and demonstrated the involvement and underlying mechanisms of ncRNAs in modulating BBB structure and function in various CNS diseases, including ischemic stroke, hemorrhagic stroke, traumatic brain injury (TBI), spinal cord injury (SCI), multiple sclerosis (MS), Alzheimer's disease (AD), vascular cognitive impairment and dementia (VCID), brain tumors, brain infections, diabetes, sepsis-associated encephalopathy (SAE), and others. We have also discussed the pharmaceutical drugs that can regulate BBB functions via ncRNAs-related signaling cascades in CNS disorders, along with the challenges, perspective, and therapeutic potential of ncRNA regulation of BBB functions in CNS diseases.

The role of microRNAs in epithelial to mesenchymal transition and cancers; focusing on mir-200 family

Epithelial to mesenchymal transition (EMT) is a process associated with cancer malignancy and metastases. Cells undergoing EMT lose their epithelial phenotype and acquire mesenchymal phenotype. This process is accompanied by several molecular changes such as decrease of E-cadherin and increase of N-cadherin which is called the "cadherin swich". MicroRNAs (miRNAs, miRs) are small non-coding RNAs having ability to regulate genes post-transcriptionally. Nowadays they are believed to take part in multiple physiological and pathological processes including cancer development. Comparison between TargetScan7 (www.targetscan.org) results for miR-200b and metanalysis of genes involved in EMT showed that miR-200b has a potential binding site in 60 genes that are involved in EMT (the majority of them were associated with mesenchymal phenotype). Our review summarizes literature findings contributing to experimentally proven interactions between miR-200b and genes involved in EMT process including cell receptors, signaling pathways, cell cycle or cell adhesion. The results of those interactions indicate that miR-200b may have an inhibitory impact on EMT or even in selected cases is able to restore epithelial phenotype.

Effect of miRNA-200b on the proliferation and apoptosis of cervical cancer cells by targeting RhoA

Objective

This article aims to investigate the effect of miRNA-200b on the proliferation and apoptosis of cervical cancer cells by targeting RhoA.

Methods

HeLa cells of cervical cancer were divided into five groups: blank control group, negative control group (miRNA-200b mimic NC), miRNA-200b mimic group, RhoA-negative control group, and RhoA overexpression group. Cells were collected 48 h after transfection. The expression levels of miRNA-200b were detected by RT-PCR. Target relationship between miRNA-200b and RhoA was verified by the dual-luciferase reporter assay. RhoA mRNA and protein expression were detected by western blot and RT-PCR methods. Flow cytometry was used to detect the apoptosis of cells in each group, and the CCK8 method was used to detect the proliferation of cells in each group. The mRNA and protein expression of Bax and cyclin D1 were detected by RT-PCR and western blot.

Results

The results of the dual luciferase reporter assay showed that RhoA was the target gene of microRNA 200b. Compared with the blank control group and the miRNA-200b mimic-NC group, the proportion of apoptotic cells increased significantly in the miRNA-200b mimic group, and the proliferation of cells was inhibited (P < 0.05). After overexpression of RhoA, the percentage of apoptotic cells decreased and the ability of cell proliferation increased significantly (P < 0.05).

Conclusion

miRNA-200b can inhibit the proliferation and promote the apoptosis of cervical cancer cells by targeting the RhoA gene.

Transplantation of Wnt5a-modified NSCs promotes tissue repair and locomotor functional recovery after spinal cord injury

Traditional therapeutic strategies for spinal cord injury (SCI) are insufficient to repair locomotor function because of the failure of axonal reconnection and neuronal regeneration in the injured central nervous system (CNS). Neural stem cell (NSC) transplantation has been considered a potential strategy and is generally feasible for repairing the neural circuit after SCI; however, the most formidable problem is that the neuronal differentiation rate of NSCs is quite limited. Therefore, it is essential to induce the neuronal differentiation of NSCs and improve the differentiation rate of NSCs in spinal cord repair. Our results demonstrate that both Wnt5a and miRNA200b-3p could promote NSC differentiation into neurons and that Wnt5a upregulated miRNA200b-3p expression through MAPK/JNK signaling to promote NSC differentiation into neurons. Wnt5a could reduce RhoA expression by upregulating miRNA200b-3p expression to inhibit activation of the RhoA/Rock signaling pathway, which has been reported to suppress neuronal differentiation. Overexpression of RhoA abolished the neurogenic capacity of Wnt5a and miRNA200b-3p. In vivo, miRNA200b-3p was critical for Wnt5a-induced NSC differentiation into neurons to promote motor functional and histological recovery after SCI by suppressing RhoA/Rock signaling. These findings provide more insight into SCI and help with the identification of novel treatment strategies.

Incorporating key molecules into neural stem cells enhances their ability to differentiate correctly and promote repair following spinal cord injury. Spinal cord injuries can have a debilitating effect on patients’ lives, yet there are no therapies that fully restore movement and sensation. Therapies based on neural stem cells (NSCs) show promise, but initial studies show many NSCs differentiate into astrocytes, supportive cells that do not conduct nerve impulses, instead of neurons, leading to treatment failure. Yong Wan and Le Wang at Sun Yat-sen University in Guangzhou, China, and co-workers demonstrated that adding a protein called Wnt5a and a specific microRNA molecule to NSCs significantly increases differentiation into neurons. Wnt5a suppresses a signalling pathway that otherwise interferes with NSC differentiation. Experiments on rat models showed that the therapy improved locomotor function and tissue repair after injury.

Mast cells-derived MiR-223 destroys intestinal barrier function by inhibition of CLDN8 expression in intestinal epithelial cells

Background

Mast cells (MCs) have been found to play a critical role during development of inflammatory bowel disease (IBD) that characterized by dysregulation of inflammation and impaired intestinal barrier function. However, the function of MCs in IBD remains to be fully elucidated.

Results

In our study, we used exosomes isolated from human mast cells-1 (HMCs-1) to culture with NCM460, HT-29 or CaCO2 of intestinal epithelial cells (IECs) to investigate the communication between MCs and IECs. We found that MCs-derived exosomes significantly increased intestinal epithelial permeability and destroyed intestinal barrier function, which is attributed to exosome-mediated functional miRNAs were transferred from HMCs-1 into IECs, leading to inhibit tight junction-related proteins expression, including tight junction proteins 1 (TJP1, ZO-1), Occludin (OCLN), Claudin 8 (CLDN8). Microarray and bioinformatic analysis have further revealed that a panel of miRNAs target different tight junction-related proteins. Interestingly, miR-223 is enriched in mast cell-derived exosome, which inhibit CLDN8 expression in IECs, while treatment with miR-223 inhibitor in HT-29 cells significantly reversed the inhibitory effect of HMCs-1-derived exosomes on CLDN 8 expression. Most importantly, enrichment of MCs accumulation in intestinal mucosa of patients with IBD compared with those healthy control.

Conclusions

These results indicated that enrichment of exosomal miR-223 from HMCs-1 inhibited CLDN8 expression, leading to destroy intestinal barrier function. These finding provided a novel insight of MCs as a new target for therapeutic treatment of IBD.

MicroRNAs in central nervous system diseases: A prospective role in regulating blood-brain barrier integrity

Given the essential role of the blood-brain barrier (BBB) in the central nervous system (CNS), cumulative investigations have been performed to elucidate how modulation of BBB structural and functional integrity affects the pathogenesis of CNS diseases such as stroke, traumatic brain injuries, dementia, and cerebral infection. Recent studies have demonstrated that microRNAs (miRNAs) contribute to the maintenance of the BBB and thereby mediate CNS homeostasis. This review summarizes emerging studies that demonstrate cerebral miRNAs regulate BBB function in CNS disorders, emphasizing the direct role of miRNAs in BBB molecular composition. Evidence presented in this review will encourage a deeper understanding of the mechanisms by which miRNAs regulate BBB function, and facilitate the development of new miRNAs-based therapies in patients with CNS diseases.

miRNA-200b improves hepatic fibrosis induced by CCL4 by regulating toll-like receptor 4 in mice

To study the effect of miRNA-200b on hepatic fibrosis induced by CCl4 in mice. The C59BL/6 mice were randomly divided into three groups (normal control [NC], CCLR model [Model], and CCl 4  + miRNA-200b [miRNA]). The hepatic fibrosis was induced by CCl 4 injected subcutaneously twice per week in Model and miRNA groups. After 6 weeks building model, the mice of miRNA group were injected the miRNA-200b from caudal vein twice per week. The mice of Model and miRNA groups were continuously fed for 3 weeks. The IL-1β, IL-6, and TNF-α concentrations of serum were measured by enzyme-linked immunosorbent assay. The hepatic tissues of difference groups were observed by hematoxylin and eosin (H&E) staining, sirius red staining, Masson staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling assay and measured toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) proteins expressions by western blot assay. The correlation between miRNA-200b and TLR4 were analyzed by dual luciferase target assay. Compared with NC group, the interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) concentrations of Model group were significantly upregulated (P < 0.05, respectively). With miRNA-200b overexpression, the IL-1β, IL-6, and TNF-α concentrations were significantly suppressed (P < 0.05, respectively). The pathologies were improved by H&E staining, sirius red staining, and Masson staining; meanwhile, the hepatic cell apoptosis rate was significantly suppressed (P < 0.05). The TLR4 and NF-κB protein expressions of miRNA group were significantly suppressed compared with the Model group (P < 0.05, respectively). By dual luciferase target assay, the TLR4 was a target gene of miRNA-200b. The miRNA-200b upregulation improved hepatic fibrosis induced by CCl 4 via regulation of TLR4 in vivo.

Mechanism of piR-DQ590027/MIR17HG regulating the permeability of glioma conditioned normal BBB

Background

The blood-brain barrier (BBB) strongly restricts the entry of anti-glioma drugs into tumor tissues and thus decreases chemotherapy efficacy. Malignant gliomas are highly invasive tumours that use the perivascular space for invasion and co-opt existing vessels as satellite tumor form. Because regulation of the effect of noncoding RNA on BBB function is attracting growing attention, we investigated the effects of noncoding RNA on the permeability of glioma conditioned normal BBB and the mechanism involved using PIWI-associated RNA piR-DQ590027 as a starting point.

Methods

The mRNA levels of MIR17HG, miR-153, miR-377, ZO-1, occludin, and claudin-5 were determined using real-time PCR. Transient cell transfection was performed using Lipofectamine 3000 reagent. TEER and HRP flux were applied to measure the permeability of glioma conditioned normal BBB. Western blotting and immunofluorescence assays were used to measure ZO-1, occludin, and claudin-5 levels. Reporter vector construction and a luciferase reporter assay were performed to detect the binding sites of MIR17HG and piR-DQ590027, MIR17HG and miR-153 (miR-377), and FOXR2 and miR-153 (miR-377). RNA immunoprecipitation was used to test the interaction between miR-153 (miR-377) and its target proteins. Chromatin immunoprecipitation was performed to detect the interaction between the transcription factor FOXR2 and ZO-1, occludin, and claudin-5.

Results

piR-DQ590027 was expressed at low levels in glioma-conditioned ECs (GECs) of the in vitro glioma conditioned normal BBB model. Overexpression of piR-DQ590027 down-regulated the expressions of ZO-1, occludin, and claudin-5 and increased the permeability of glioma conditioned normal BBB. MIR17HG had high expression in GECs but miR-153 and miR-377 had low expression. piR-DQ590027 bound to and negatively regulated MIR17HG. FOXR2 was a downstream target of miR-153 and miR-377; MIR17HG bound separately to miR-153 and miR-377 and negatively regulated their ability to mediate FOXR2 expression. FOXR2 associated with the promoter regions of ZO-1, occludin, and claudin-5 in GECs to promote their transcription.

Conclusion

The piR-DQ590027/MIR17HG/miR-153 (miR-377)/FOXR2 pathway plays an important role in regulating glioma conditioned normal BBB permeability and provides a new target for the comprehensive treatment of glioma.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0886-0) contains supplementary material, which is available to authorized users.

The miR-200 family: multiple effects on gliomas

Gliomas are the most common type of primary brain tumors. MicroRNAs (miRNAs) are small noncoding RNAs that can epigenetically regulate target gene expression. The microRNA 200 family includes miR-200a, 200b, 200c, 141 and 429. Numerous studies have indicated that members of the miR-200 family play an important role in glioma development and metastasis. In this review, we summarize the data from various studies and highlight the effects of miR-200 on glioma metastasis, therapeutic response and prognosis.

MiR-429 Regulated by Endothelial Monocyte Activating Polypeptide-II (EMAP-II) Influences Blood-Tumor Barrier Permeability by Inhibiting the Expressions of ZO-1, Occludin and Claudin-5

The blood-tumor barrier (BTB) hinders delivery of chemotherapeutic drugs to tumors in the brain; previous studies have shown that the BTB can be selectively opened by endothelial monocyte activating polypeptide-II (EMAP-II), but the specific mechanism involved remains elusive. In this study, we found that microRNA-429 (miR-429) expression in glioma vascular endothelial cells (GECs) was far lower than in human brain microvascular endothelial cells (ECs). miR-429 had lower expression in GECs and glioma tissues compared to ECs or normal tissues of the brain. Furthermore, miR-429 had lower expression in high grade glioma (HGG) than in low grade glioma (LGG). In in vitro BTB models, we also found that EMAP-II significantly increased BTB permeability, decreased expression of ZO-1, occludin and claudin-5 in GECs, in a time- and dose-dependent manner. EMAP-II greatly increased miR-429 expression in GECs of the BTB models in vitro. Overexpression of miR-429 in GECs significantly decreased the transepithelial electric resistance (TEER) values in BTB models, and led to enhanced horseradish peroxidase (HRP) flux. Overexpression of miR-429 in GECs significantly decreased the expression of tight junction (TJ)-associated proteins (ZO-1, occludin and claudin-5), and decreased the distribution continuity. Silencing of miR-429 in GECs increased the expression of TJ-associated proteins and the distribution continuity. The dual-luciferase reporter assay revealed that ZO-1 and occludin were target genes of miR-429, and we demonstrated that miR-429 overexpression markedly down-regulated protein expression of p70S6K, as well as its phosphorylation levels. The dual-luciferase reporter assay also showed that p70S6K was a target gene of miR-429; miR-429 overexpression down-regulated expression and phosphorylation levels of p70S6K, and also decreased phosphorylation levels of S6 and increased BTB permeability. Conversely, silencing of miR-429 increased the expression and phosphorylation levels of p70S6K, and increased phosphorylation levels of S6, while decreasing BTB permeability. In conclusion, the results indicated that EMAP-II caused an increase in miR-429 expression that directly targeted TJ-associated proteins, which were negatively regulated; on the other hand, miR-429 down-regulated the expression of TJ-associated proteins by targeting p70S6K, also negatively regulated. As a result, the BTB permeability increased.

Vinorelbine Delivery and Efficacy in the MDA-MB-231BR Preclinical Model of Brain Metastases of Breast Cancer

PURPOSE

To evaluate vinorelbine drug exposure and activity in brain metastases of the human MDA-MB-231BR breast cancer model using integrated imaging and analysis.

METHODS

Brain and systemic metastases were created by administration of cancer cells in female NuNu mice. After metastases developed, animals were administered vinorelbine at the maximal tolerated dose (12 mg/kg), and were evaluated thereafter for total and unbound drug pharmacokinetics, biomarker TUNEL staining, and barrier permeability to Texas red.

RESULTS

Median brain metastasis drug exposure was 4-fold greater than normal brain, yet only ~8% of non-barrier systemic metastases, which suggests restricted brain exposure. Unbound vinorelbine tissue/plasma partition coefficient, K_p,uu, equaled ~1.0 in systemic metastases, but 0.03-0.22 in brain metastases, documenting restricted equilibration. In select sub-regions of highest drug-uptake brain metastases, K_p,uu approached 1.0, indicating complete focal barrier breakdown. Most vinorelbine-treated brain metastases exhibited little or no positive early apoptosis TUNEL staining in vivo. The in vivo unbound vinorelbine IC₅₀ for TUNEL-positive staining (56 nM) was 4-fold higher than that measured in vitro (14 nM). Consistent with this finding, P-glycoprotein expression was observed to be substantially upregulated in brain metastasis cells in vivo.

CONCLUSIONS

Vinorelbine exposure at maximum tolerated dose was less than one-tenth that in systemic metastases in >70% of brain metastases, and was associated with negligible biomarker effect. In small subregions of the highest uptake brain metastases, compromise of blood-tumor barrier appeared complete. The results suggest that restricted delivery accounts for 80% of the compromise in drug efficacy for vinorelbine against this model.