Circular RNAs and neutrophils: Key factors in tackling asymptomatic moyamoya disease

Knockdown the moyamoya disease susceptibility gene, RNF213, upregulates the expression of basic fibroblast growth factor and matrix metalloproteinase-9 in bone marrow derived mesenchymal stem cells

Moyamoya disease (MMD) is a chronic, progressive cerebrovascular occlusive disease. Ring finger protein 213 (RNF213) is a susceptibility gene of MMD. Previous studies have shown that the expression levels of angiogenic factors increase in MMD patients, but the relationship between the susceptibility gene RNF213 and these angiogenic mediators is still unclear. The aim of the present study was to investigate the pathogenesis of MMD by examining the effect of RNF213 gene knockdown on the expression of matrix metalloproteinase-9 (MMP-9) and basic fibroblast growth factor (bFGF) in rat bone marrow-derived mesenchymal stem cells (rBMSCs). Firstly, 40 patients with MMD and 40 age-matched normal individuals (as the control group) were enrolled in the present study to detect the levels of MMP-9 and bFGF in serum by ELISA. Secondly, Sprague-Dawley male rat BMSCs were isolated and cultured using the whole bone marrow adhesion method, and subsequent phenotypic analysis was performed by flow cytometry. Alizarin red and oil red O staining methods were used to identify osteogenic and adipogenic differentiation, respectively. Finally, third generation rBMSCs were transfected with lentivirus recombinant plasmid to knockout expression of the RNF213 gene. After successful transfection was confirmed by reverse transcription-quantitative PCR and fluorescence imaging, the expression levels of bFGF and MMP-9 mRNA in rBMSCs and the levels of bFGF and MMP-9 protein in the supernatant of the culture medium were detected on the 7th and 14th days after transfection. There was no significant difference in the relative expression level of bFGF among the three groups on the 7th day. For the relative expression level of MMP-9, there were significant differences on the 7th day and 14th day. In addition, there was no statistically significant difference in the expression of bFGF in the supernatant of the RNF213 shRNA group culture medium, while there was a significant difference in the expression level of MMP-9. The knockdown of the RNF213 gene affects the expression of bFGF and MMP-9. However, further studies are needed to determine how they participate in the pathogenesis of MMD. The findings of the present study provide a theoretical basis for clarifying the pathogenesis and clinical treatment of MMD.

Overexpression of Circ_0005585 Alleviates Cerebral Ischemia Reperfusion Injury via Targeting MiR-16-5p

Circular RNAs are implicated in the pathogenesis of ischemic stroke. In this work, we explored the modulation and potential mechanisms of action of circ_0005585 in ischemic stroke. Expression of circ_0005585 and miR-16-5p was assessed by quantitative real-time reverse transcription PCR. Ischemic stroke was modeled in mice by middle cerebral artery occlusion (MCAO). The infarct volume was assessed by triphenyl tetrazolium chloride staining. Neurological deficits were evaluated according to Neurological Severity Score. The permeability of the blood-brain barrier was assessed by Evan's blue leakage and brain water content. Apoptosis in brain tissues was measured by the TUNEL test. Relative expression of apoptosis-related proteins was evaluated by Western blotting. The direct interaction between circ_0005585 and miR-16-5p was verified by dual-luciferase reporter assay. The expression of circ_0005585 was lower in mice with MCAO. Lentivirus-mediated overexpression of circ_0005585 ameliorated the neurological deficits and decreased the infarction volume in MCAO mice. The brain water content and Evan's blue leakage through the blood-brain barrier were reduced. In addition, overexpression of circ_0005585 inhibited apoptosis in the cerebral tissues. Our results revealed direct interaction between circ_0005585 and miR-16-5p. Hence, circ_0005585 protects mouse brain during ischemic stroke by targeting miR-16-5p, which uncovers the pathogenesis of this pathology and opens new vitas for its therapy.

Physiological and pathophysiological mechanisms of the molecular and cellular biology of angiogenesis and inflammation in moyamoya angiopathy and related vascular diseases

Rationale

The etiology and pathophysiological mechanisms of moyamoya angiopathy (MMA) remain largely unknown. MMA is a progressive, occlusive cerebrovascular disorder characterized by recurrent ischemic and hemorrhagic strokes; with compensatory formation of an abnormal network of perforating blood vessels that creates a collateral circulation; and by aberrant angiogenesis at the base of the brain. Imbalance of angiogenic and vasculogenic mechanisms has been proposed as a potential cause of MMA. Moyamoya vessels suggest that aberrant angiogenic, arteriogenic, and vasculogenic processes may be involved in the pathophysiology of MMA. Circulating endothelial progenitor cells have been hypothesized to contribute to vascular remodeling in MMA. MMA is associated with increased expression of angiogenic factors and proinflammatory molecules. Systemic inflammation may be related to MMA pathogenesis.

Objective

This literature review describes the molecular mechanisms associated with cerebrovascular dysfunction, aberrant angiogenesis, and inflammation in MMA and related cerebrovascular diseases along with treatment strategies and future research perspectives.

Methods and results

References were identified through a systematic computerized search of the medical literature from January 1, 1983, through July 29, 2022, using the PubMed, EMBASE, BIOSIS Previews, CNKI, ISI web of science, and Medline databases and various combinations of the keywords "moyamoya," "angiogenesis," "anastomotic network," "molecular mechanism," "physiology," "pathophysiology," "pathogenesis," "biomarker," "genetics," "signaling pathway," "blood-brain barrier," "endothelial progenitor cells," "endothelial function," "inflammation," "intracranial hemorrhage," and "stroke." Relevant articles and supplemental basic science articles almost exclusively published in English were included. Review of the reference lists of relevant publications for additional sources resulted in 350 publications which met the study inclusion criteria. Detection of growth factors, chemokines, and cytokines in MMA patients suggests the hypothesis of aberrant angiogenesis being involved in MMA pathogenesis. It remains to be ascertained whether these findings are consequences of MMA or are etiological factors of MMA.

Conclusions

MMA is a heterogeneous disorder, comprising various genotypes and phenotypes, with a complex pathophysiology. Additional research may advance our understanding of the pathophysiology involved in aberrant angiogenesis, arterial stenosis, and the formation of moyamoya collaterals and anastomotic networks. Future research will benefit from researching molecular pathophysiologic mechanisms and the correlation of clinical and basic research results.

Identification of immune-infiltrated hub genes as potential biomarkers of Moyamoya disease by bioinformatics analysis

Background

Moyamoya disease (MMD) is a rare chronic progressive cerebrovascular disease. Recent studies have shown that autoimmune inflammation may also be an important pathology in MMD but the molecular mechanisms of inflammation in this disease are still large unknown. This study was designed to identify key biomarkers and the immune infiltration in vessel tissue of MMD using bioinformatics analysis.

Methods

Raw gene expression profiles (GSE157628, GSE141024) were downloaded from the Gene Expression Omnibus (GEO) database, identified differentially expressed genes (DEGs) and performed functional enrichment analysis. The CIBERSORT deconvolution algorithm was used to analyze the proportion of immune cells between MMD and an MMD-negative control group. We screened for neutrophil-associated DEGs, constructed a protein–protein interaction network (PPI) using STRING, and clarified the gene cluster using the Cytoscape plugin MCODE analysis. The receiver operating characteristic (ROC) curve was applied to test and filter the best gene signature.

Results

A total of 570 DEGs were detected, including 212 downregulated and 358 up-regulated genes. Reactome and KEGG enrichment revealed that DEGs were involved in the cell cycle, molecular transport, and metabolic pathways. The immune infiltration profile demonstrated that MMD cerebrovascular tissues contained a higher proportion of neutrophils, monocytes, and natural killer cells in MMD than in controls. The PPI network and MCODE cluster identified nine DEGs (UNC13D, AZU1, PYCARD, ELANE, SDCBP, CCL11, CCL15, CCL20, and CXCL5) associated with neutrophil infiltration. ROC results showed that UNC13D has good specificity and sensitivity (AUC = 0.7846).

Conclusions

The characteristics of immune infiltration in the cerebrovascular tissues of MMD patients and abnormal expression of hub genes provide new insights for understanding MMD progression. UNC13D is shows promise as a candidate molecule to determine neutrophil infiltration characteristics in MMD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02238-4.

RNF213 gene silencing upregulates transforming growth factor β1 expression in bone marrow-derived mesenchymal stem cells and is involved in the onset of Moyamoya disease

Moyamoya disease (MMD) is a chronic and progressive cerebrovascular occlusion disease, the precise etiology of which is poorly understood. Ring finger protein 213 (RNF213) has been previously identified as a susceptibility gene that serves an important role in angiogenesis, where it has been shown to be closely associated with the onset of MMD. Patients with MMD exhibit increased expression levels of various pro-inflammatory molecules and angiogenic factors. Under certain conditions, bone marrow mesenchymal stem cells (BMSCs) have the ability to differentiate to form neuron-like and microglia-like cells. In the present study, a total of 40 MMD patients and 40 healthy individuals were enrolled. ELISA assays revealed that the expression of serum vascular endothelial growth factor (VEGF) and transforming growth factor β1 (TGF-β1) were higher than that in healthy controls. Furthermore, rat BMSCs (rBMSCs) were isolated and cultured using the whole bone marrow adherence method, which were then phenotyped using flow cytometry. Osteogenic and adipogenic differentiation were determined by using Alizarin red and oil red O staining, respectively. RNF213 was knocked-down using a lentivirus-mediated short hairpin RNA system in passage three rBMSCs, and successful transfection of the RNF213 was confirmed by RT-qPCR and fluorescence imaging. The expression levels of VEGF and TGF-β1 in these rBMSCs were measured on days 7 and 14, respectively. The results demonstrated that RNF213 knockdown upregulated TGF-β1 at both protein and mRNA levels, but did not exert any effect on VEGF gene expression. In conclusion, these findings suggested that that RNF213 knockdown may contribute to aberrant TGF-β1 expression via a pathway that remains to be unidentified, indicating that quantitative changes in RNF213 gene expression may serve an important role in the pathogenesis of MMD.

Overexpression of circRNA circUCK2 Attenuates Cell Apoptosis in Cerebral Ischemia-Reperfusion Injury via miR-125b-5p/GDF11 Signaling

Circular RNAs (circRNAs) are expressed at high levels in the brain and are involved in various central nervous system diseases. However, the potential role of circRNAs in ischemic stroke-associated neuronal injury remains largely unknown. Herein, we uncovered the function and underlying mechanism of the circRNA UCK2 (circUCK2) in ischemia stroke. The oxygen-glucose deprivation model in HT-22 cells was used to mimic ischemia stroke in vitro. Neuronal viability and apoptosis were determined by Cell Counting Kit-8 (CCK-8) assays and TUNEL (terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick end labeling) staining, respectively. Middle cerebral artery occlusion was conducted to evaluate the function of circUCK2 in mice. The levels of circUCK2 were significantly decreased in brain tissues from a mouse model of focal cerebral ischemia and reperfusion. Upregulated circUCK2 levels significantly decreased infarct volumes, attenuated neuronal injury, and improved neurological deficits. circUCK2 reduced oxygen glucose deprivation (OGD)-induced cell apoptosis by regulating transforming growth factor β (TGF-β)/mothers against decapentaplegic homolog 3 (Smad3) signaling. Furthermore, circUCK2 functioned as an endogenous miR-125b-5p sponge to inhibit miR-125b-5p activity, resulting in an increase in growth differentiation factor 11 (GDF11) expression and a subsequent amelioration of neuronal injury. Consequently, these findings showed that the circUCK2/miR-125b-5p/GDF11 axis is an essential signaling pathway during ischemia stroke. Thus, the circRNA circUCK2 may serve as a potential target for novel treatment in patients with ischemic stroke.

Stem cell-based regenerative medicine for neurological disorders: A special tribute to Dr. Teng Ma

This special issue of Brain Circulation presents cutting-edge research discoveries in stem cell-based regenerative medicine. Each article highlights recent advances in the fields of neurodegeneration and regenerative medicine. The selected contributions offer the groundwork for translating stem cell therapy to the clinic for treating central nervous system disorders. This issue is dedicated to Dr. Teng Ma, who passed away on May 18, 2019. Dr. Ma devoted a significant portion of his life in advancing biomedical engineering, including the utility of 3-dimensional bioreactor and magnetic resonance imaging, as a key element of the biological and therapeutic applications of stem cells for neurological disorders. Dr. Ma's research vision is celebrated in this compilation of ten articles on stem cell-based regenerative medicine.