Prevalence of RNF213 variants in symptomatic intracranial arterial stenosis/occlusion in China

Detailed phenotype of RNF213 p.R4810K variant identified by the Chinese patients with acute ischaemic stroke or transient ischaemic attack

BACKGROUND AND PURPOSE

The ring finger protein 213 gene (RNF213) p.R4810K variant increased the risk of acute ischaemic stroke (AIS) attributable to intracranial arterial stenosis (ICAS) in the Japanese and Korean populations. In this study, we aimed to examine the prevalence of the RNF213 p.R4810K variant in Chinese patients with AIS or transient ischaemic attack and identify the phenotype of the carriers.

METHODS

We analysed data from the Third China National Stroke Registry. All included participants were divided into two groups by carrier status of the p.R4810K variant. The aetiological classification was conducted according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. The presence of ICAS and extracranial arterial stenosis (ECAS) was defined as 50%-99% stenosis or occlusion of any intracranial and extracranial artery. Logistic regression models and Cox regression models were used to evaluate the association of the p.R4810K variant with TOAST classification, stenosis phenotypes and clinical outcomes.

RESULTS

A total of 10 381 patients were enrolled, among which 56 (0.5%) had the heterozygote GA genotype for p.R4810K. The variant carriers were younger (p=0.01), and more likely to suffer from peripheral vascular disease (p=0.04). The p.R4810K variant was associated with large-artery atherosclerosis (LAA) (adjusted OR=1.94, 95% CI 1.13 to 3.33), anterior circulation stenosis (adjusted OR=2.12, 95% CI 1.23 to 3.65) and ECAS (adjusted OR=2.29, 95% CI 1.16 to 4.51). Nevertheless, the p.R4810K variant was not associated with recurrence, poor functional outcome and mortality at 3 months and 1 year.

CONCLUSIONS

The RNF213 p.R4810K variant was associated with LAA, anterior circulation stenosis and ECAS in Chinese patients. Given the low carrying rate and only 1-year follow-up information, caution should be taken to interpret our findings in no statistically significant association between the p.R4810K variant and stroke prognosis in Chinese patients.

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.