Targeting pericyte-endothelial cell crosstalk by circular RNA-cPWWP2A inhibition aggravates diabetes-induced microvascular dysfunction.

The crosstalk between vascular pericytes and endothelial cells (ECs) is critical for microvascular stabilization and remodeling; however, the crosstalk is often disrupted by diabetes, leading to severe and even lethal vascular damage. Circular RNAs are a class of endogenous RNAs that regulate several important physiological and pathological processes. Here we show that diabetes-related stress up-regulates cPWWP2A expression in pericytes but not in ECs. In vitro studies show that cPWWP2A directly regulates pericyte biology but indirectly regulates EC biology via exosomes carrying cPWWP2A. cPWWP2A acts as an endogenous miR-579 sponge to sequester and inhibit miR-579 activity, leading to increased expression of angiopoietin 1, occludin, and SIRT1. In vivo studies show that cPWWP2A overexpression or miR-579 inhibition alleviates diabetes mellitus-induced retinal vascular dysfunction. By contrast, inhibition of cPWWP2A-mediated signaling by silencing cPWWP2A or overexpressing miR-579 aggravates retinal vascular dysfunction. Collectively, this study unveils a mechanism by which pericytes and ECs communicate. Intervention of cPWWP2A or miR-579 expression may offer opportunities for treating diabetic microvascular complications.

Circular Noncoding RNA HIPK3 Mediates Retinal Vascular Dysfunction in Diabetes Mellitus.

BACKGROUND: The vascular complications of diabetes mellitus are the major causes of morbidity and mortality among people with diabetes. Circular RNAs are a class of endogenous noncoding RNAs that regulate gene expression in eukaryotes. In this study, we investigated the role of circular RNA in retinal vascular dysfunction induced by diabetes mellitus. METHODS: Quantitative polymerase chain reactions, Sanger sequencing, and Northern blots were conducted to detect circular HIPK3 (circHIPK3) expression pattern on diabetes mellitus-related stresses. MTT (3-[4,5-dimethythiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assays, EdU (5-ethynyl-2'-deoxyuridine) incorporation assays, Transwell migration assays, and Matrigel assays were conducted to detect the role of circHIPK3 in retinal endothelial cell function in vitro. Retinal trypsin digestion, vascular permeability assays, and ELISA assays were conducted to detect the role of circHIPK3 in retinal vascular dysfunction in vivo. Bioinformatics analysis, luciferase activity assays, RNA pull-down assays, and in vitro studies were conducted to reveal the mechanism of circHIPK3-mediated retinal vascular dysfunction. RESULTS: circHIPK3 expression was significantly upregulated in diabetic retinas and retinal endothelial cells following stressors related to diabetes mellitus. circHIPK3 silencing or overexpressing circHIPK3 changed retinal endothelial cell viability, proliferation, migration, and tube formation in vitro. circHIPK3 silencing in vivo alleviated retinal vascular dysfunction, as shown by decreased retinal acellular capillaries, vascular leakage, and inflammation. circHIPK3 acted as an endogenous miR-30a-3p sponge to sequester and inhibit miR-30a-3p activity, which led to increased vascular endothelial growth factor-C, FZD4, and WNT2 expression. Ectopic expression of miR-30a-3p mimicked the effect of circHIPK3 silencing on vascular endothelial phenotypes in vivo and in vitro. CONCLUSIONS: The circular RNA circHIPK3 plays a role in diabetic retinopathy by blocking miR-30a function, leading to increased endothelial proliferation and vascular dysfunction. These data suggest that circular RNA is a potential target to control diabetic proliferative retinopathy.

Expression Profiling Identifies Circular RNA Signature in Hepatoblastoma.

BACKGROUND/AIMS: Hepatoblastoma is the most common malignant pediatric liver cancer. circular RNAs (circRNAs) play important roles in fine-tuning gene expression and are often deregulated in cancers. However, the expression profile and clinical significance of circRNAs in hepatoblastoma is still unknown. METHODS: Circular RNA microarray was conducted to identify hepatoblastoma-related circRNAs. GO analysis, pathway analysis, and miRNA response elements analysis was conducted to predict the potential roles of differentially expressed circRNAs in hepatoblastoma. MTT assays, Ki67 staining, and Transwell assays were conducted to clarify the role of circRNA in hepatoblastoma in vitro. Bioinformatics analysis and in vitro experiments were conducted to clarify the mechanism of circRNA-mediated gene regulation in hepatoblastoma cell. RESULTS: 869 differentially expressed circRNAs were identified between hepatoblastoma and adjacent normal liver samples, including 421 up-regulated circRNAs and 448 down-regulated circRNAs. The significant enriched GO term of hepatoblastoma-related circRNAs in biological process, cellular component, and molecular function were "chromosome organization", "cytoplasm", and "organic cyclic compound binding". Tight junction signaling pathway was ranked the Top 1 potentially affected by circRNA-mediated regulatory network. circ_0015756 was significantly up-regulated in human hepatoblastoma specimens and metastatic hepatoblastoma cell lines. circ_0015756 silencing decreased hepatoblastoma cell viability, proliferation, and invasion in vitro. circ_0015756 acted as miR-1250-3p sponge to regulate hepatoblastoma cell function. CONCLUSIONS: circRNAs are involved in the pathogenesis of hepatoblastoma. circ_0015756 is a promising target for the prognosis, diagnosis, and treatment of hepatoblastoma.

CPEB4 interacts with Vimentin and involves in progressive features and poor prognosis of patients with astrocytic tumors.

Cytoplasmic polyadenylation element binding protein 4 (CPEB4) is a regulator of gene transcription and has been reported to be associated with biological malignancy in cancers. However, it is unclear whether CPEB4 has any clinical significance in patients with astrocytic tumors, and mechanisms that CPEB4 contribute to progression of astrocytic tumors remain largely unknown. Here, correlation between CPEB4 expression and prognosis of patients with astrocytic tumors were explored by using qPCR, WB and IHC, and X-tile, SPSS software. Cell lines U251 MG and A172 were used to study CPEB4's function and mechanisms. Co-immunoprecipitation, mass spectrometry, immunofluorescent assay, and western blot were performed to observe the interaction between CPEB4 and Vimentin. CPEB4 mRNA and protein levels were markedly elevated in 12/12 astrocytic tumors in comparison to paratumor. High expression of CPEB4 was significantly correlated with clinical progressive futures and work as an independent adverse prognostic factor for overall survival of patients with astrocytic tumors (relative risk 4.5, 95 % CI 2.1-11.2, p = 0.001). Moreover, knockdown of CPEB4 in astrocytic tumor cells inhibited their proliferation ability , clonogenicity, and invasiveness. Five candidate proteins, GRP78, Mortalin, Keratin, Vimentin, and ß-actin, were identified, and the interaction between CPEB4 and Vimentin was finally confirmed. Downregulation of CPEB4 could reduce the protein expression of Vimentin. Our studies first validated that CPEB4 interacts with Vimentin and indicated that high CPEB4 expression in astrocytic tumors correlates closely with a clinically aggressive future, and that CPEB4 might represent a valuable prognostic marker for patients with astrocytic tumors.

Tumor Suppressive Role of MUC6 in Wilms Tumor via Autophagy-Dependent ß-Catenin Degradation.

Wilms tumor is the most common renal malignancy in children. Known gene mutations account for about 40% of all wilms tumor cases, but the full map of genetic mutations in wilms tumor is far from clear. Whole genome sequencing and RNA sequencing were performed in 5 pairs of wilms tumor tissues and adjacent normal tissues to figure out important genetic mutations. Gene knock-down, CRISPR-induced mutations were used to investigate their potential effects in cell lines and in-vivo xenografted model. Mutations in seven novel genes (MUC6, GOLGA6L2, GPRIN2, MDN1, MUC4, OR4L1 and PDE4DIP) occurred in more than one patient. The most prevalent mutation was found in MUC6, which had 7 somatic exonic variants in 4 patients. In addition, TaqMan assay and immunoblot confirmed that MUC6 expression was reduced in WT tissues when compared with control tissues. Moreover, the results of MUC6 knock-down assay and CRISPR-induced MUC6 mutations showed that MUC6 inhibited tumor aggression via autophagy-dependent ß-catenin degradation while its mutations attenuated tumor-suppressive effects of MUC6. Seven novel mutated genes (MUC6, GOLGA6L2, GPRIN2, MDN1, MUC4, OR4L1 and PDE4DIP) were found in WT, among which MUC6 was the most prevalent one. MUC6 acted as a tumor suppressive gene through autophagy dependent ß-catenin pathway.

Circular RNA-ZNF532 regulates diabetes-induced retinal pericyte degeneration and vascular dysfunction.

Diabetic retinopathy (DR) is the leading cause of blindness in working-age adults. Vascular pericyte degeneration is the predominant clinical manifestation of DR, yet the mechanism governing pericyte degeneration is poorly understood. Circular RNAs (circRNAs) play important roles in multiple biological processes and disease progression. Here, we investigated the role of circRNA in pericyte biology and diabetes-induced retinal vascular dysfunction. cZNF532 expression was upregulated in pericytes under diabetic stress, in the retinal vessels of a diabetic murine model, and in the vitreous humor of diabetic patients. cZNF532 silencing reduced the viability, proliferation, and differentiation of pericytes and suppressed the recruitment of pericytes toward endothelial cells in vitro. cZNF532 regulated pericyte biology by acting as a miR-29a-3p sponge and inducing increased expression of NG2, LOXL2, and CDK2. Knockdown of cZNF532 or overexpression of miR-29a-3p aggravated streptozotocin-induced retinal pericyte degeneration and vascular dysfunction. By contrast, overexpression of cZNF532 or inhibition of miR-29a-3p ameliorated human diabetic vitreous-induced retinal pericyte degeneration and vascular dysfunction. Collectively, these data identify a circRNA-mediated mechanism that coordinates pericyte biology and vascular homeostasis in DR. Induction of cZNF532 or antagonism of miR-29a-3p is an exploitable therapeutic approach for the treatment of DR.

Single-Cell Characterization of Malignant Phenotypes and Developmental Trajectories of Adrenal Neuroblastoma.

Neuroblastoma (NB), which is a subtype of neural-crest-derived malignancy, is the most common extracranial solid tumor occurring in childhood. Despite extensive research, the underlying developmental origin of NB remains unclear. Using single-cell RNA sequencing, we generate transcriptomes of adrenal NB from 160,910 cells of 16 patients and transcriptomes of putative developmental cells of origin of NB from 12,103 cells of early human embryos and fetal adrenal glands at relatively late development stages. We find that most adrenal NB tumor cells transcriptionally mirror noradrenergic chromaffin cells. Malignant states also recapitulate the proliferation/differentiation status of chromaffin cells in the process of normal development. Our findings provide insight into developmental trajectories and cellular states underlying human initiation and progression of NB.

Mesoporous silica nanoparticles as a delivery system for improving antiangiogenic therapy.

PURPOSE: Antiangiogenic drugs usually have short-acting efficacy and poor treatment compliance. The purpose of this study was to determine whether mesoporous silica nanoparticles (MSNs) could be utilized as a nanodrug delivery system for improving antiangiogenic therapy. MATERIALS AND METHODS: MSN-encapsulated bevacizumab nanoparticles were prepared by the nanocasting strategy and characterized by Fourier transform infrared, transmission electron microscopy, and Brunauer-Emmett-Teller method. Encapsulation efficiency and drug loading efficiency of MSN-encapsulated bevacizumab nanoparticles were calculated. The pharmacokinetics, cytotoxicity, and tissue toxicity were evaluated in vitro and in vivo. The antiangiogenic effects of MSN-bevacizumab nanoparticles were evaluated in vitro and in vivo. RESULTS: MSN encapsulation could prolong the residency of bevacizumab in vitreous/aqueous humor and maintain the long-lasting drug concentration. MSN-encapsulated bevacizumab nanoparticles did not show any obvious cytotoxicity and tissue toxicity. MSN-encapsulated bevacizumab nanoparticles were more effective than bevacizumab in suppressing vascular endothelial growth factor-induced endothelial cell proliferation, migration, and tube formation in vitro. MSN-encapsulated bevacizumab nanoparticles showed sustained inhibitory effects on corneal neovascularization and retinal neovascularization in vivo. CONCLUSION: This study provides a novel strategy of encapsulating bevacizumab to protect and deliver it, which could increase the time between administration and formulation shelf-life. MSN-encapsulated bevacizumab is a promising drug delivery alternative of antiangiogenic therapy.

Effect of nanoencapsulation using poly (lactide-co-glycolide) (PLGA) on anti-angiogenic activity of bevacizumab for ocular angiogenesis therapy.

Antibody-based therapy is an effective strategy for treating ocular angiogenesis. However, short-acting efficacy and poor treatment compliance usually occurs in clinical practices. Thus, it is required to develop a drug delivery system to improve the bioavailability and decrease the toxicity of anti-angiogenic antibody. Bevacizumab is a recombinant humanized monoclonal antibody against vascular endothelial growth factor (VEGF). In this study, bevacizumab was encapsulated into poly (lactide-co-glycolide) (PLGA) nanoparticles. PLGA encapsulation could prolong the residency of bevacizumab in the vitreous and aqueous humor and produce long-lasting drug concentrations. Bevacizumab-encapsulated PLGA had no significant cytotoxicity and tissue toxicity effect in vitro and in vivo. In vitro studies showed that bevacizumab-encapsulated PLGA was more effective than bevacizumab in inhibiting VEGF-mediated endothelial cell proliferation, migration and tube formation. In vivo studies showed that bevacizumab-encapsulated PLGA enhanced the anti-angiogenic efficiency of bevacizumab for treating corneal neovascularization and retinal neovascularization. Thus, bevacizumab-encapsulated PLGA could increase the bioavailability and decrease the toxicity of bevacizumab during ocular angiogenesis therapy.

Circular RNA-ZNF609 regulates retinal neurodegeneration by acting as miR-615 sponge.

Glaucoma is a major cause of visual impairment characterized by progressive retinal neurodegeneration. Circular RNAs are a class of endogenous noncoding RNAs that regulate gene expression in eukaryotes. In this study, we investigated the role of cZNF609 in retinal neurodegeneration induced by glaucoma. Methods: qRT-PCR and Sanger sequencing were conducted to detect cZNF609 expression pattern during retinal neurodegeneration. Immunofluorescence staining was conducted to detect the effect of cZNF609 silencing on retinal neurodegeneration in vivo. MTT assay, Ki67 staining, and PI staining were conducted to detect the effect of cZNF609 silencing on retinal glial cells and RGC function in vitro. Bioinformatics analysis, RNA pull-down assays, and in vitro studies were conducted to reveal the mechanism of cZNF609-mediated retinal neurodegeneration. Results: cZNF609 expression was significantly up-regulated during retinal neurodegeneration. cZNF609 silencing reduced retinal reactive gliosis and glial cell activation, and facilitated RGC survival in vivo. cZNF609 silencing directly regulated Müller cell function but indirectly regulated RGC function in vitro. cZNF609 acted as an endogenous miR-615 sponge to sequester and inhibit miR-615 activity, which led to increased METRN. METRN overexpression could partially rescue cZNF609 silencing-mediated inhibitory effects on retinal glial cell proliferation. Conclusion: Intervention of cZNF609 expression is a promising therapeutic strategy for retinal neurodegeneration.

Targeting circular RNA-ZRANB1 for therapeutic intervention in retinal neurodegeneration.

Glaucoma is a neurodegenerative disease characterized by retinal ganglion cell (RGC) loss, optic disc excavation, and progressive visual field loss. Direct or indirect ameliorating retinal neurodegeneration is a promising therapeutic therapy for glaucoma. Circular RNAs (circRNAs) are a class of covalently closed circular RNA transcripts and have emerged as potential regulators in several neurodegenerative diseases. In this study, we show that cZRANB1 expression is significantly upregulated in retinal neurodegeneration induced by glaucoma. cZRANB1 knockdown decreases retinal reactive gliosis, glial cell activation, and facilitates RGC survival in vivo. cZRANB1 knockdown directly regulates Müller cell function and indirectly regulates RGC function in vitro. cZRANB1 acts as miRNA sponge to regulate Müller cell function through cZRANB1/miR-217/RUNX2 network. Intervention of cZRANB1 expression would become an effective strategy for treating retinal neurodegeneration.

Long non-coding RNA-CRNDE: a novel regulator of tumor growth and angiogenesis in hepatoblastoma.

Long non-coding RNAs (lncRNAs) are involved in many biological processes, such as angiogenesis, invasion, cell proliferation, and apoptosis. They have emerged as key players in the pathology of several tumors, including hepatoblastoma. In this study, we elucidate the biological and clinical significance of CRNDE up-regulation in hepatoblastoma. CRNDE is significantly up-regulated in human hepatoblastoma specimens and metastatic hepatoblastoma cell lines. CRNDE knockdown reduces tumor growth and tumor angiogenesis in vivo, and decreases hepatoblastoma cell viability, proliferation, and angiogenic effect in vitro. Mechanistic studies show that CRNDE knockdown plays its anti-proliferation and anti-angiogenesis role via regulating mammalian target of rapamycin (mTOR) signaling. Taken together, this study reveals a crucial role of CRNDE in the pathology of hepatoblastoma. CRNDE may serve as a promising diagnostic marker and therapeutic target for hepatoblastoma.

Identification and Characterization of Circular RNAs as a New Class of Putative Biomarkers in Diabetes Retinopathy.

Purpose: To reveal the expression profile and clinical significance of circular RNAs (circRNAs) in diabetic retinopathy (DR). Methods: Circular RNA microarrays were performed to identify DR-related circRNAs. Gene ontology (GO) enrichment and KEGG analysis was performed to determine the biologic modules and signaling pathway. TargetScan and miRana program was used to predict circRNA/miRNA interaction. Quantitative PCR assays were performed to detect circRNA expression pattern in clinical samples. Ki67 staining, Transwell, tube formation, and spheroid sprouting assays were performed to investigate the role and mechanism of circRNA in endothelial angiogenic function. Results: A total of 529 circRNAs were aberrantly expressed in diabetic retinas. The host genes of differentially expressed circRNAs were targeted to ATP binding (biologic process); extracellular exosome (cellular component); and intracellular signal transduction (molecular function). Circ_0005015 was verified to be upregulated in the plasma, vitreous sample, and fibrovascular membranes of DR patients. Circ_0005015 facilitated retinal endothelial angiogenic function via regulating endothelial cell proliferation, migration, and tube formation. Circ_0005015 acted as miR-519d-3p sponge to inhibit miR-519d-3p activity, leading to increased MMP-2, XIAP, and STAT3 expression. Conclusions: circRNAs are involved in DR pathogenesis, and thus serve as potential biomarkers of DR diagnosis.