Moyamoya Disease Susceptibility Gene RNF213 Regulates Endothelial Barrier Function

Glymphatic Impairment Associated with Neurocognitive Dysfunction in Moyamoya Disease

Glymphatic system alterations have been proved to be associated with cognitive dysfunction in neurodegenerative diseases. The glymphatic pathway has not been elucidated in moyamoya disease (MMD), which was recognized as a chronic hypoperfusion model for neurodegenerative disease. Here, we aimed to investigate the glymphatic system activity and its relation with neurocognition, and associated hallmarks in MMD. We prospectively recruited 30 MMD patients and 30 matched healthy controls (HC). Participants underwent MRI and neurocognition evaluation. The glymphatic function was assessed by diffusion tensor image analysis along perivascular space (DTI-ALPS) index. Gray matter volume (GMV) and microstructural alterations were calculated. Neurodegenerative-related serum biomarkers were examined. The mediation effect of ALPS index in the associations between variables and neurocognition were further explored. A lower ALPS index was identified in patients with MMD (P < 0.001). The decreased ALPS index was significantly correlated with declined neurocognitive performance. Moreover, the reduced ALPS index was notably linked with lower total GMV% and deep GMV% (P < 0.01). Microstructural changes in the periventricular areas were detected and associated with ALPS index in MMD. Serum neurodegenerative biomarkers (ApoE, Aβ40, Aβ42, and Aβ42/Aβ40) were significantly elevated and related to ALPS index. Additionally, the ALPS index significantly mediated the associations of microstructural alterations and ApoE level with neurocognitive dysfunction. The ALPS index was notably lower MMD in patients, suggesting the utility as a marker of potential glymphatic dysfunction. The index acted as a significant mediator in neurocognitive dysfunction. These findings indicated that glymphatic impairment may interact with MMD-related pathophysiological processes.

Molecular mechanisms of endothelial-mesenchymal transition and its pathophysiological feature in cerebrovascular disease

The phenomenon of endothelial-mesenchymal transition (EndMT), a distinct subtype of epithelial-mesenchymal transition (EMT), has garnered significant attention from scholars. EndMT refers to the process whereby endothelial cells (ECs) transform into mesenchymal cells in response to various stimuli, resulting in the loss of their original characteristics. This process has diverse implications in both physiological and pathological states. Under physiological conditions, EndMT plays a crucial role in the development of the cardiovascular system. Conversely, under pathological conditions, EndMT has been identified as a pivotal factor in the development of cardiovascular diseases. Nonetheless, a comprehensive overview of EndMT in cerebrovascular disease is currently lacking. Here, we discuss the heterogeneity of EndMT occurrence and the regulatory factors involved in its development and analyze the feasibility of EndMT as a therapeutic target, aiming to provide a solid theoretical foundation and evidence to address diseases caused by pathological EndMT.

The role of the RING finger protein 213 gene in Moyamoya disease

Moyamoya Disease (MMD) represents a chronic and progressive cerebrovascular disorder characterized by the gradual occlusion of the terminal portions of the bilateral internal carotid arteries and their major branches, accompanied by the formation of abnormal vascular networks at the base of the skull. In adolescents, particularly in pediatric populations, MMD is a significant cause of stroke, posing a severe challenge to human health and imposing a heavy burden on healthcare systems. Ring Finger Protein 213 (RNF213), as the primary susceptibility gene for MMD, plays a crucial regulatory role in the initiation, progression, and prognosis of the disease. Despite extensive research on the role of RNF213 in the pathogenesis of MMD, the underlying molecular mechanisms remain incompletely understood and represent a pressing scientific challenge requiring further exploration. This review aims to synthesize the latest research findings and systematically elucidate the multifaceted roles of RNF213 in MMD, including genetic susceptibility, immune-inflammatory responses, blood-brain barrier(BBB) disruption, and angiogenesis. By integrating these findings, this study seeks to provide new insights and theoretical support for a comprehensive and in-depth understanding of the pathophysiological processes of MMD. This research not only contributes to further unraveling the complex pathogenesis of MMD but also lays a solid theoretical foundation for the development of targeted preventive and therapeutic strategies.

Identification of the potential role of S1PR1 in adult moyamoya disease based on multiple bioinformatics analysis and experimental verification

Moyamoya disease (MMD) is a chronic occlusive cerebrovascular ailment with a progressively rising incidence, yet its precise etiology and pathogenesis remain elusive. Adult MMD-related datasets GSE189993 and GSE157628 were procured from the GEO database for screening of differentially expressed genes (DEGs). Weighted gene co-expression network analysis (WGCNA) was employed to unveil the most significant module associated with MMD. Least absolute shrinkage and selection operator (LASSO) logistic regression was used to identify and validate diagnostic markers for MMD. CIBERSORT and ssGSEA analyses were conducted to estimate immune cell infiltration in MMD vessels. In vitro experiments were performed to validate the biological functions of Sphingosine-1-phosphate receptor 1 (S1PR1) in mouse aortic smooth muscle cells (MOVAS). A total of 436 DEGs were identified from GSE189993, comprising 202 up-regulated genes and 234 down-regulated genes. Within the green-yellow module, 87 genes overlapped with DEGs, and 6 genes were identified by Cytoscape as key factors in the pathophysiology of MMD, namely, platelet endothelial cell adhesion molecule 1 (PECAM1), von Willebrand factor (VWF), intercellular cell adhesion molecule 1 (ICAM1), vascular endothelial growth factor C (VEGFC), tissue-type plasminogen activator (PLAT), and S1PR1. Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses also showed that key genes were mainly involved in endothelial cells and cell adhesion-related biological function. About 13 diagnostic genes were obtained by the LASSO regression algorithm, with S1PR1 emerging as a hub gene demonstrating good diagnostic performance in both the test set and validation set. Finally, we validated that overexpression of S1PR1 spurred viability, proliferation, and cell division in mouse aortic smooth muscle cells (MOVAS) and human cerebral vascular smooth muscle cells (HCVSMC) by activating the PI3K/AKT signaling pathway. S1PR1 has been identified as a hub gene for MMD. S1PR1 overexpression has been linked to enhanced cell division and proliferation in vitro, suggesting its potential as a therapeutic target for adult MMD.

Comprehensive Analysis and In Vitro Verification of Endothelial-Mesenchymal Transition-Related Genes in Moyamoya Disease

Moyamoya disease (MMD) is a rare, chronic, and progressive cerebrovascular disorder with unclear underlying causes and mechanisms. Previous studies suggest a potential involvement of endothelial-mesenchymal transition (EndMT) in the pathogenesis of MMD. This study aimed to explore the contribution of EndMT-related genes (ERGs) in MMD. Two datasets, GSE141022 and GSE157628, were integrated as the training set after batch effects removal. Differentially expressed ERGs were identified between MMD and control groups. Functional enrichment analysis and immune infiltration analysis were further performed. LASSO regression was used for hub MMD-related ERG selection. Consensus clustering was used for MMD subtype classification based on these hub MMD-related ERGs. Molecular characteristics between MMD subtypes were analyzed using WGCNA. PPI network was used to illuminate the genetic relationship. The hub MMD-related ERGs were validated in an independent testing set, GSE189993. The nomogram model was constructed and evaluated using ROC curves and calibration plots. Additionally, CCK-8, EdU, wound healing, and western blot were performed to confirm the function of the hub MMD-related ERGs. A total of 107 DE-ERGs were identified. Functional enrichment analysis showed these genes were associated with EndMT and immune response. The infiltrating levels of immune cells were commonly higher in the MMD group. LASSO regression identified 12 hub MMD-related ERGs, leading to the identification of two MMD subtypes. Four ERGs emerged as the final hub MMD-related ERGs after validation in the testing set, including CCL21, CEBPA, KRT18, and TNFRSF11A. The nomogram model exhibited excellent discrimination ability. In vitro experiments showed that CCL21, CEBPA, KRT18, and TNFRSF11A could promote proliferation, migration, and EndMT. This study investigated the potential role of EndMT in MMD and identified four hub MMD-related ERGs, providing potential therapeutic targets for MMD treatment.

The Role of Immune Cells in Moyamoya Disease

Moyamoya disease (MMD) is a rare progressive cerebrovascular disorder characterized by the stenosis or occlusion of the terminal segments of the internal carotid arteries, leading to the development of abnormal collateral vascular networks. These networks are a compensatory mechanism for reduced blood flow to the brain. Despite extensive research, the exact etiology of MMD remains unknown, although recent studies suggest that immune system dysfunction plays a critical role in its pathogenesis. In particular, the involvement of immune cells such as T cells, macrophages, and dendritic cells has been increasingly recognized. These immune cells contribute to the inflammatory process and vascular remodeling observed in MMD patients, further complicating the disease's progression. Inflammation and immune-mediated damage to the vessel walls may accelerate the narrowing and occlusion of arteries, exacerbating ischemic events in the brain. Additionally, studies have revealed that certain genetic and environmental factors can influence immune system activation in MMD, linking these pathways to disease development. This review aims to provide a comprehensive overview of the immune mechanisms at play in MMD, focusing on how immune cells participate in vascular injury and remodeling. Understanding these immunological processes may offer new therapeutic targets to halt or reverse disease progression, potentially leading to more effective treatment strategies for MMD.

Altered neurovascular coupling and structure-function coupling in Moyamoya disease affect postoperative collateral formation

Chronic ischemia in moyamoya disease (MMD) impaired white matter microstructure and neural functional network. However, the coupling between cerebral blood flow (CBF) and functional connectivity and the association between structural and functional network are largely unknown. 38 MMD patients and 20 sex/age-matched healthy controls (HC) were included for T1-weighted imaging, arterial spin labeling imaging, resting-state functional MRI and diffusion tensor imaging. All patients had preoperative and postoperative digital subtraction angiography. Upon constructing the structural connectivity (SC) and functional connectivity (FC) networks, the SC-FC coupling was calculated. After obtaining the graph theoretical parameters, neurovascular coupling represented the spatial correlation between node degree centrality (DC) of functional networks and CBF. The CBF-DC coupling and SC-FC coupling were compared between MMD and HC groups. We further analyzed the correlation between coupling indexes and cognitive scores, as well as postoperative collateral formation. Compared with HC, CBF-DC coupling was decreased in MMD (p = 0.021), especially in the parietal lobe (p = 0.047). SC-FC coupling in MMD decreased in frontal, occipital, and subcortical regions. Cognitive scores were correlated with the CBF-DC coupling in frontal lobes (r = 0.394, p = 0.029) and SC-FC coupling (r = 0.397, p = 0.027). The CBF-DC coupling of patients with good postoperative collateral formation was higher (p = 0.041). Overall, neurovascular decoupling and structure-functional decoupling at the cortical level may be the underlying neuropathological mechanisms of MMD.

Exploring RNF213 in Ischemic Stroke and Moyamoya Disease: From Cellular Models to Clinical Insights

Advances in stroke genetics have highlighted the critical role of rare genetic variants in cerebrovascular diseases, with RNF213 emerging as a key player in ischemic stroke and Moyamoya disease (MMD). Initially identified as the primary susceptibility gene for MMD, RNF213-notably the p.R4810K variant-has been strongly linked to intracranial artery stenosis (ICAS) and various ischemic stroke subtypes, particularly in East Asian populations. This gene encodes an E3 ubiquitin ligase with diverse roles in angiogenesis, vascular remodeling, lipid metabolism, and cerebral blood flow regulation, yet its exact mechanisms in cerebrovascular pathology remain incompletely understood. This review synthesizes findings from genetic studies, as well as cellular and animal models, to provide a holistic understanding of RNF213's involvement in cerebrovascular diseases. Key mechanisms by which RNF213 variants contribute to disease pathogenesis are explored, alongside discussions on their clinical utility as biomarkers and therapeutic targets. Additionally, we address the gene's implications for disease prediction, risk assessment, and cascade screening. By integrating evidence across disciplines, this review identifies critical knowledge gaps, including the biological pathways underlying RNF213's pathogenicity. These insights lay the groundwork for future research and underscore the potential of RNF213 in driving personalized approaches to cerebrovascular disease management.

RNF213 in moyamoya disease: Genotype-phenotype association and the underlying mechanism

ABSTRACT

Moyamoya disease (MMD) is a cerebrovascular disorder characterized by a steno-occlusive internal carotid artery and compensatory vascular network formation. Although the precise pathogenic mechanism remains elusive, genetic association studies have identified RNF213 as the principal susceptibility gene for MMD, with the single nucleotide polymorphism p.R4810K recognized as the founder variant predominantly in the Asian populations. Distinct genotype-phenotype correlations are observable in RNF213 -related MMD. The clinical manifestations linked to p.R4810K bear commonalities within Asian cohort, including familial predisposition, earlier age of onset, ischemic episodes, and involvement of the posterior cerebral artery (PCA). However, despite these shared phenotypic characteristics, there is significant heterogeneity in RNF213 -related MMD presentations. This diversity manifests as variations across ethnic groups, inconsistent clinical symptoms and prognosis, and occurrence of other vasculopathies involving RNF213 . This heterogeneity, in conjunction with the observed low disease penetrance of RNF213 mutations, suggests that the presence of these mutations may not be sufficient to cause MMD, underscoring the potential influence of other genetic or environmental factors. Although the current research might not have fully identified these additional contributors, experimental evidence points toward the involvement of RNF213 in angiogenesis, lipid metabolism, and the immune response. Future research is required to unveil the molecular mechanisms and identify the factors that synergize with RNF213 in the pathogenesis of MMD.

High-resolution MRI vessel wall enhancement in moyamoya disease: risk factors and clinical outcomes

OBJECTIVES

Intracranial vessel wall enhancement (VWE) on high-resolution magnetic resonance imaging (HRMRI) is associated with the progression and poor prognosis of moyamoya disease (MMD). This study assessed potential risk factors for VWE in MMD.

METHODS

We evaluated MMD patients using HRMRI and traditional angiography examinations. The participants were divided into VWE and non-VWE groups based on HRMRI. Logistic regression was performed to compare the risk factors for VWE in MMD. The incidence of cerebrovascular events of the different subgroups according to risk factors was compared using Kaplan-Meier survival and Cox regression.

RESULTS

We included 283 MMD patients, 84 of whom had VWE on HRMRI. The VWE group had higher modified Rankin Scale scores at admission (p = 0.014) and a higher incidence of ischaemia and haemorrhage (p = 0.002) than did the non-VWE group. Risk factors for VWE included the ring finger protein 213 (RNF213) p.R4810K variant (odds ratio [OR] 2.01, 95% confidence interval [CI] 1.08-3.76, p = 0.028), hyperhomocysteinaemia (HHcy) (OR 5.08, 95% CI 2.34-11.05, p < 0.001), and smoking history (OR 3.49, 95% CI 1.08-11.31, p = 0.037). During the follow-up of 63.9 ± 13.2 months (median 65 months), 18 recurrent stroke events occurred. Cox regression showed that VWE and the RNF213 p.R4810K variant were risk factors for stroke.

CONCLUSION

The RNF213 p.R4810K variant is strongly associated with VWE and poor prognosis in MMD. HHcy and smoking are independent risk factors for VWE.

CLINICAL RELEVANCE STATEMENT

Vessel wall enhancement in moyamoya disease is closely associated with poor prognosis, especially related to the ring finger protein 213 p.R4810K variant, hyperhomocysteinaemia, and smoking, providing crucial risk assessment information for the clinic.

KEY POINTS

• The baseline presence of vessel wall enhancement is significantly associated with poor prognosis in moyamoya disease. • The ring finger protein 213 p.R4810K variant is strongly associated with vessel wall enhancement and poor prognosis in moyamoya disease. • Hyperhomocysteinaemia and smoking are independent risk factors for vessel wall enhancement in moyamoya disease.

Novel analysis of functional relationship linking moyamoya disease to moyamoya syndrome

Objective

The aim of this study was to elucidate the genetic pathways associated with Moyamoya disease (MMD) and Moyamoya syndrome (MMS), compare the functional activities, and validate relevant related genes in an independent dataset.

Methods

We conducted a comprehensive search for genetic studies on MMD and MMS across multiple databases and identified related genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichments analyses were performed for these genes. Commonly shared genes were selected for further validation in the independent dataset, GSE189993. The Sangerbox platform was used to perform statistical analysis and visualize the results. P＜0.05 indicated a statistically significant result.

Results

We included 52 MMD and 51 MMS-related publications and identified 126 and 51 relevant genes, respectively. GO analysis for MMD showed significant enrichment in cytokine activity, cell membrane receptors, enzyme binding, and immune activity. A broader range of terms was enriched for MMS. KEGG pathway analysis for MMD highlighted immune and cellular activities and pathways related to MMS prominently featured inflammation and metabolic disorders. Notably, nine overlapping genes were identified and validated. The expressions of RNF213, PTPN11, and MTHFR demonstrated significant differences in GSE189993. A combined receiver operating characteristic curve showed high diagnostic accuracy (AUC = 0.918).

Conclusions

The findings indicate a close relationship of MMD with immune activity and MMS with inflammation, metabolic processes and other environmental factors in a given genetic background. Differentiating between MMD and MMS can enhance the understanding of their pathophysiology and inform the strategies for their diagnoses and treatment.

Moyamoya disease in a 2-year-old patient from the middle east: a case report and literature review

Introduction and importance

Moyamoya disease (MMD) is a condition characterized by progressive narrowing of arteries in the brain and abnormal development of small collateral vessels. It is commonly found in East Asia but has never been reported in Palestine.

Case presentation

A 2-year-old female, part of a twin born to non-consanguineous parents, presented with recurring seizures and developmental regression. The physical examination revealed signs of hypotonia, reflex abnormalities, and bilateral Babinski signs. Comprehensive laboratory tests and imaging investigations confirmed the diagnosis of MMD, marking this patient as the reported case in Palestine.

Clinical discussion

The diagnostic criteria for this condition were revised in 2021 to focus on findings seen in angiography and magnetic resonance angiography (MRA) scans. MMD has not been curative so far, and the management is focused on preventing complications, sometimes with surgical revascularization, including its different approaches: direct, indirect, and a combination of both.

Conclusion

This case highlights the importance of identifying MMD in regions where it is uncommon to be diagnosed. It emphasizes the need for diagnosis and appropriate intervention to reduce complications.

Ubiquitous regulation of cerebrovascular diseases by ubiquitin-modifying enzymes

Cerebrovascular diseases (CVDs) are a major threat to global health. Elucidation of the molecular mechanisms underlying the pathology of CVDs is critical for the development of efficacious preventative and therapeutic approaches. Accumulating studies have highlighted the significance of ubiquitin-modifying enzymes (UMEs) in the regulation of CVDs. UMEs are a group of enzymes that orchestrate ubiquitination, a post-translational modification tightly involved in CVDs. Functionally, UMEs regulate multiple pathological processes in ischemic and hemorrhagic stroke, moyamoya disease, and atherosclerosis. Considering the important roles of UMEs in CVDs, they may become novel druggable targets for these diseases. Besides, techniques applying UMEs, such as proteolysis-targeting chimera and deubiquitinase-targeting chimera, may also revolutionize the therapy of CVDs in the future.

High glutamine increases stroke risk by inducing the endothelial-to-mesenchymal transition in moyamoya disease

At present, there is limited research on the mechanisms underlying moyamoya disease (MMD). Herein, we aimed to determine the role of glutamine in MMD pathogenesis, and 360 adult patients were prospectively enrolled. Human brain microvascular endothelial cells (HBMECs) were subjected to Integrin Subunit Beta 4 (ITGB4) overexpression or knockdown and atorvastatin. We assessed factors associated with various signaling pathways in the context of the endothelial-to-mesenchymal transition (EndMT), and the expression level of related proteins was validated in the superficial temporal arteries of patients. We found glutamine levels were positively associated with a greater risk of stroke (OR = 1.599, p = 0.022). After treatment with glutamine, HBMECs exhibited enhanced proliferation, migration, and EndMT, all reversed by ITGB4 knockdown. In ITGB4-transfected HBMECs, the MAPK-ERK-TGF-β/BMP pathway was activated, with Smad4 knockdown reversing the EndMT. Furthermore, atorvastatin suppressed the EndMT by inhibiting Smad1/5 phosphorylation and promoting Smad4 ubiquitination in ITGB4-transfected HBMECs. We also found the protein level of ITGB4 was upregulated in the superficial temporal arteries of patients with MMD. In conclusion, our study suggests that glutamine may be an independent risk factor for hemorrhage or infarction in patients with MMD and targeting ITGB4 could potentially be therapeutic approaches for MMD.

Neuregulin 1 as a potential biomarker for disease progression in moyamoya disease: A case-control study in Chinese population

OBJECTIVE

Moyamoya disease (MMD) is a rare and progressive stenosis of cerebral arteries characterized by abnormally proliferative vasculopathy. Current studies have demonstrated that Neuregulin 1 (NRG1) plays a key role in angiogenesis-related disorders. Thus, the aim of our study is to investigate the serum NRG1 levels and their clinical correlations in MMD patients.

METHODS

In this study, thirty adult patients with MMD and age-gender matched healthy controls were enrolled from our hospital between July 2020 and April 2022. Peripheral blood samples were collected at baseline, and clinical data were obtained from the electronic medical record system. Serum NRG1 concentrations were measured by enzyme-linked immunosorbent assay. Sanger sequencing was applied to detect the RNF213 p.R4810K mutation.

RESULTS

The serum NRG1 levels were significantly higher in MMD patients compared to controls (14.48 ± 10.81 vs.7.54 ± 6.35mmol/L, p < 0.001). No statistical difference in baseline clinical characteristics was found between both groups. Correlation analyses showed that NRG1 levels were positively associated with Suzuki staging (r = 0.4137, p = 0.023) while not related to other clinical features (reduced cerebral blood flow, posterior cerebral artery involvement, bilateral or unilateral steno-occlusive changes). Furthermore, subgroup analysis revealed that MMD patients with the RNF213 p.R4810K mutation presented with significantly higher NRG1 levels than those without the mutation (9.60 ± 0.929 vs. 25.89 ± 4.338 mmol/L, p = 0.001).

CONCLUSIONS

Our study suggests that increased serum NRG1 levels may constitute a characteristic feature of MMD, indicating a potential positive correlation with disease progression and the presence of the RNF213 mutation. This positions NRG1 as a potentially crucial target for further studies aimed at comprehending the pathogenesis of MMD.

Association of lysine pathway metabolites with moyamoya disease

BACKGROUND AND OBJECTIVE

Lysine and its pathway metabolites have been identified as novel biomarkers for metabolic and vascular diseases. The role of them in the identification of moyamoya disease (MMD) has not been elucidated. This study aimed to determine the association between lysine pathway metabolites and the presence of MMD.

METHODS

We prospectively enrolled 360 MMD patients and 89 healthy controls from September 2020 to December 2021 in Beijing Tiantan Hospital. Serum levels of lysine, pipecolic acid and 2-aminoadipic acid were measured by liquid chromatography-mass spectrometry. We employed logistic regression and restricted cubic spline to explore the association between these metabolites and the presence of MMD. Stratified analyses were also conducted to test the robustness of results.

RESULTS

We observed that lysine levels in MMD patients were significantly higher and pipecolic acid levels were significantly lower compared to HCs (both p < 0.001), while no difference was found in the level of 2-AAA between both groups. When comparing metabolites by quartiles, elevated lysine levels were linked to increased odds for MMD (the fourth quartile [Q4] vs the first quartile [Q1]: odds ratio, 3.48, 95%CI [1.39-8.75]), while reduced pipecolic acid levels correlated with higher odds (Q4 vs Q1: odds ratio, 0.08; 95 % CI [0.03-0.20]). The restricted cubic spline found a L-shaped relationship between pipecolic acid level and the presence of MMD, with a cutoff point at 2.52 μmol/L. Robust results were also observed across subgroups.

CONCLUSION

Elevated lysine levels were correlated with increased odds of MMD presence, while lower pipecolic acid levels were associated with higher odds of the condition. These results suggest potential new biomarkers for the identification of MMD.

CLINICAL TRIAL REGISTRY NUMBER

URL: https://www.chictr.org.cn/. Unique identifier: ChiCTR2200061889.

Is medical management useful in Moyamoya disease?

Moyamoya disease (MMD), characterized by progressive internal carotid artery stenosis and collateral vessel formation, prompts cerebral perfusion complications and is stratified into idiopathic and Moyamoya syndrome subtypes. A multifaceted approach toward MMD management addresses cerebral infarctions through revascularization surgery and adjunctive medical therapy, while also navigating risks such as intracranial hemorrhage and cerebral infarction resulting from arterial stenosis and fragile collateral vessels. Addressing antithrombotic management reveals a potential role for treatments like antiplatelet agents and anticoagulants, despite the ambiguous contribution of thrombosis to MMD-related infarctions and the critical balance between preventing ischemic events and averting hemorrhagic complications. Transcranial doppler has proven useful in thromboembolic detection, despite persisting challenges concerning the efficacy and safety of antithrombotic treatments. Furthermore, antihypertensive interventions aim to manage blood pressure meticulously, especially during intracerebral hemorrhage, with recommendations and protocols varying based on the patient's hypertension status. Additionally, lipid-lowering therapeutic strategies, particularly employing statins, are appraised for their possible beneficial role in MMD management, even as comprehensive data from disease-specific clinical trials remains elusive. Comprehensive guidelines and protocols to navigate the multifaceted therapeutic avenues for MMD, while maintaining a delicate balance between efficacy and safety, warrant further meticulous research and development. This protocol manuscript seeks to elucidate the various aspects and challenges imbued in managing and navigating through the complex landscape of MMD treatment.

Glycosylation: A new signaling paradigm for the neurovascular diseases

A wide range of life-threatening conditions with complicated pathogenesis involves neurovascular disorders encompassing Neurovascular unit (NVU) damage. The pathophysiology of NVU is characterized by several features including tissue hypoxia, stimulation of inflammatory and angiogenic processes, and the initiation of intricate molecular interactions, collectively leading to an elevation in blood-brain barrier permeability, atherosclerosis and ultimately, neurovascular diseases. The presence of compelling data about the significant involvement of the glycosylation in the development of diseases has sparked a discussion on whether the abnormal glycosylation may serve as a causal factor for neurovascular disorders, rather than being just recruited as a secondary player in regulating the critical events during the development processes like embryo growth and angiogenesis. An essential tool for both developing new anti-ischemic therapies and understanding the processes of ischemic brain damage is undertaking pre-clinical studies of neurovascular disorders. Together with the post-translational modification of proteins, the modulation of glycosylation and its enzymes implicates itself in several abnormal activities which are known to accelerate neuronal vasculopathy. Despite the failure of the majority of glycosylation-based preclinical and clinical studies over the past years, there is a significant probability to provide neuroprotection utilizing modern and advanced approaches to target abnormal glycosylation activity at embryonic stages as well. This article focuses on a variety of experimental evidence to postulate the interconnection between glycosylation and vascular disorders along with possible treatment options.

A Noonan-like pediatric patient with a de novo CBL pathogenic variant and an RNF213 polymorphism p.R4810K presenting with cardiopulmonary arrest due to left main coronary artery ostial atresia

Left main coronary artery ostial atresia (LMCAOA) is an extremely rare condition. Here, we report the case of a 14-year-old boy with Noonan syndrome-like disorder in whom LMCAOA was detected following cardiopulmonary arrest. The patient had been diagnosed with Noonan syndrome-like disorder with a pathogenic splice site variant of CBL c.1228-2 A > G. He suddenly collapsed when he was running. After administering two electric shocks using an automated external defibrillator, the patient's heartbeat resumed. Cardiac catheterization confirmed the diagnosis of LMCAOA. Left main coronary artery angioplasty was performed. The patient was discharged without neurological sequelae. Brain magnetic resonance imaging revealed asymptomatic Moyamoya disease. In addition, RNF213 c.14429 G > A p.R4810K was identified. There are no reports on congenital coronary malformations of compound variations of RNF213 and CBL. In contrast, the RNF213 p.R4810K polymorphism has been established as a risk factor for angina pectoris and myocardial infarction in adults, and several congenital coronary malformations due to genetic abnormalities within the RAS/MAPK signaling pathway have been reported. This report aims to highlight the risk of sudden death in patients with RASopathy and RNF213 p.R4810K polymorphism and emphasize the significance of actively searching for coronary artery morphological abnormalities in these patients.

RNF213 loss-of-function promotes pathological angiogenesis in moyamoya disease via the Hippo pathway

Moyamoya disease is an uncommon cerebrovascular disorder characterized by steno-occlusive changes in the circle of Willis and abnormal vascular network development. Ring finger protein 213 (RNF213) has been identified as an important susceptibility gene for Asian patients, but researchers have not completely elucidated whether RNF213 mutations affect the pathogenesis of moyamoya disease. Using donor superficial temporal artery samples, whole-genome sequencing was performed to identify RNF213 mutation types in patients with moyamoya disease, and histopathology was performed to compare morphological differences between patients with moyamoya disease and intracranial aneurysm. The vascular phenotype of RNF213-deficient mice and zebrafish was explored in vivo, and RNF213 knockdown in human brain microvascular endothelial cells was employed to analyse cell proliferation, migration and tube formation abilities in vitro. After bioinformatics analysis of both cell and bulk RNA-seq data, potential signalling pathways were measured in RNF213-knockdown or RNF213-knockout endothelial cells. We found that patients with moyamoya disease carried pathogenic mutations of RNF213 that were positively associated with moyamoya disease histopathology. RNF213 deletion exacerbated pathological angiogenesis in the cortex and retina. Reduced RNF213 expression led to increased endothelial cell proliferation, migration and tube formation. Endothelial knockdown of RNF213 activated the Hippo pathway effector Yes-associated protein (YAP)/tafazzin (TAZ) and promoted the overexpression of the downstream effector VEGFR2. Additionally, inhibition of YAP/TAZ resulted in altered cellular VEGFR2 distribution due to defects in trafficking from the Golgi apparatus to the plasma membrane and reversed RNF213 knockdown-induced angiogenesis. All these key molecules were validated in ECs isolated from RNF213-deficient animals. Our findings may suggest that loss-of-function of RNF213 mediates the pathogenesis of moyamoya disease via the Hippo pathway.

Rnf-213 Knockout Induces Pericyte Reduction and Blood-Brain Barrier Impairment in Mouse

Moyamoya disease (MMD) is a rare cerebrovascular disorder characterized by progressive occlusion of the internal carotid artery and the formation of an abnormal compensatory capillary network at the base of the brain. Genomics studies identified Ring finger protein 213 (RNF213) as a common genetic factor that increases the susceptibility to MMD in East Asian people. However, the function of RNF213 and its roles in pathogenesis of MMD is unclear. Here, we showed that genetic knockout of Rnf213 in mice causes significant pericyte reduction and blood-brain barrier impairment in the cortex. These phenotypes are accompanied with microglia activation and elevated level of proinflammatory cytokines. Additionally, Rnf213-deficient mice showed reduced expression of tight junction proteins, including Occludin, Claudin-5, and ZO-1. Together, these data suggested that RNF213 might contribute to the pathogenesis of MMD through disruption of pericyte homeostasis and blood-brain barrier integrity by dysregulation of inflammatory responses and tight junction formation.

Association of thyroid peroxidase antibody with the RNF213 p.R4810K variant in ischemic stroke/transient ischemic attack

BACKGROUND AND AIMS

RNF213 is a susceptibility gene for moyamoya disease and vasospastic angina, with a second hit considered necessary for their development. Elevated thyroid peroxidase antibody (TPO-Ab) levels have been observed in both diseases, suggesting a possible role of TPO-Ab as a second hit for developing RNF213-related vasculopathy. We investigated the association of TPO-Ab levels with RNF213-related ischemic stroke (IS)/transient ischemic attack (TIA), other than moyamoya disease.

METHODS

From the National Cerebral and Cardiovascular Center Genome Registry, a multicenter, prospective, observational study, we enrolled patients with IS/TIA who were admitted within 1 week of onset. Patients with IS/TIA due to definite moyamoya disease or hemorrhagic stroke were excluded. Participants underwent genotyping for RNF213 p. R4810K, and baseline characteristics and TPO-Ab levels were compared between RNF213 p. R4810K variant carriers and non-carriers.

RESULTS

In total, 2090 IS/TIA patients were analyzed [733 women (35.1%); median age 74 (interquartile range, 63-81) years, baseline NIHSS score 3 (2-6)], and 85 (4.1%) of them carried the variant. Median TPO-Ab levels were significantly higher in variant carriers (8.5 IU/mL vs. 2.1 IU/mL, p < 0.01), who also showed a higher frequency of elevated TPO-Ab levels (>16 IU/mL) (27.1% vs. 4.4%). In the multivariate analysis, presence of the RNF213 p. R4810K variant (adjusted odds ratio, 12.42; 95% confidential interval, 6.23-24.75) was significantly associated with elevated TPO-Ab levels.

CONCLUSIONS

Elevated TPO-Ab levels may be significantly associated with presence of the RNF213 p. R4810K variant in IS/TIA patients. Thus, TPO-Ab may inherently modify IS/TIA development in RNF213 p. R4810K variant carriers.

A Case of Multiple Intracranial Major Artery Stenoses With Coexisting PCSK9 p.E32K and RNF213 p.R4810K Variants

Objectives

Familial hypercholesterolemia (FH), caused by PCSK9 p.E32K, is characterized by early-onset coronary artery disease. However, the relationship between PCSK9 p.E32K and cerebrovascular disease is unclear. One of our patients with the PCSK9 p.E32K had several intracranial artery stenoses (ICAS). The objective of this case series was to identify factors that may be associated with ICAS in the variant carriers.

Methods

A 75-year-old Japanese woman with FH carrying PCSK9 p.E32K was found to have 5 asymptomatic ICAS when brain magnetic resonance angiography (MRA) was performed. We retrospectively investigated additional patients with FH who underwent brain MRA at our institution to explore the unknown factors accelerating ICAS.

Results

We investigated an additional 5 patients with FH who underwent brain MRA. Of them, only one had mild ICAS. The RNF213 p.R4810K that is an established genetic risk for ICAS, particularly in East Asians, was identified only in the patient with 5 ICAS.

Discussion

PCSK9 and RNF213 play an important role in lipid metabolism and endothelial integrity. Therefore, together, these variants could be involved in the development of multiple ICAS. Our case series indicated that PCSK9 p.E32K carriers should undergo early brain screening to obtain appropriate stroke prevention measures in the asymptomatic stage.

The Progression of Pathophysiology of Moyamoya Disease

Moyamoya disease (MMD) is a chronic steno-occlusive cerebrovascular disease that often leads to hemorrhagic and ischemic strokes; however, its etiology remains elusive. Surgical revascularization by either direct or indirect bypass techniques to restore cerebral hypoperfusion is the treatment of choice to date. This review aims to provide an overview of the current advances in the pathophysiology of MMD, including the genetic, angiogenic, and inflammatory factors related to disease progression. These factors may cause MMD-related vascular stenosis and aberrant angiogenesis in complex manners. With a better understanding of the pathophysiology of MMD, nonsurgical approaches that target the pathogenesis of MMD may be able to halt or slow the progression of this disease.

Amplified Risk of Intracranial Artery Stenosis/Occlusion Associated With RNF213 p.R4810K in Familial Hypercholesterolemia

Background

The RNF213 p.R4810K variant is associated with moyamoya disease in East Asian individuals and increases the risk of developing intracranial major artery stenosis/occlusion (ICASO) that affects anterior circulation. Meanwhile, 0.5% to 2.5% of asymptomatic East Asian individuals also carry this variant. As such, additional factors are likely required to develop ICASO in variant carriers. Familial hypercholesterolemia (FH) is a common genetic disorder in Japan that has a significant associated risk of developing premature coronary atherosclerosis; however, the relationship between ICASO and FH remains unknown.

Objectives

This study aimed to determine if FH facilitates RNF213 p.R4810K carriers to develop ICASO.

Methods

We enrolled patients with FH who had undergone brain magnetic resonance angiography at our hospital from May 2005 to March 2020. The RNF213 p.R4810K variant, and LDLR and PCSK9 mutations were genotyped. ICASO lesions in the brain magnetic resonance angiogram were analyzed.

Results

Six RNF213 p.R4810K variant carriers were identified among 167 patients with FH (LDLR, n = 104; PCSK9, n = 22). Five of the carriers (83.3%) exhibited ICASO in the anterior circulation; a significant difference in ICASO frequency was observed between the variant carriers and noncarriers (P = 0.025). The median number of stenotic or occluded arteries in the anterior circulation was also significantly larger in the variant carriers (3 vs 1, P = 0.01); however, did not differ between patients with FH with LDLR and PCSK9 mutations.

Conclusions

Patients with FH exhibit increased prevalence and severity of ICASO associated with RNF213 p.R4810K. Gene mutations for FH may confer an increased risk of ICASO in RNF213 p.R4810K carriers.

Association between statin therapy and the risk of stroke in patients with moyamoya disease: a nationwide cohort study

BACKGROUND AND OBJECTIVE

Knowledge regarding the pharmacological treatment for moyamoya disease (MMD), a chronic and progressive cerebrovascular disease conferring greater stroke risk, is limited. In the present study, whether statin therapy is associated with a reduced risk of stroke in patients with MMD was investigated.

METHODS

This was a retrospective cohort study in which the occurrence of stroke in patients with newly diagnosed MMD was investigated using the nationwide health insurance database in Korea from January 2007 to March 2021. A multivariable Cox proportional hazards regression model was constructed for stroke, in which statin therapy after MMD diagnosis was treated as a time-dependent variable. Adjustment was done for sex, age, presence of comorbidities, concurrent stroke, revascularisation surgery and treatment with antiplatelets.

RESULTS

The present study included 13 373 newly diagnosed patients with MMD; 40.8% had a concurrent stroke at the time of MMD diagnosis. During the mean follow-up of 5.1±3.3 years, 631 patients (4.7%) suffered a stroke event (haemorrhagic stroke: 458 patients, ischaemic stroke: 173 patients). Statin therapy after MMD diagnosis was significantly associated with a reduced risk of stroke (adjusted HR 0.74; 95% CI 0.60 to 0.91, p=0.004). In the secondary outcome analysis, the risk of haemorrhagic stroke (adjusted HR 0.74; 95% CI 0.58 to 0.95, p=0.018) and ischaemic stroke (adjusted HR 0.75; 95% CI 0.52 to 1.08, p=0.124) were reduced with the statin treatment. Taking statins was also associated with a lower risk of all-cause mortality (adjusted HR 0.47; 95% CI 0.33 to 0.67, p<0.001).

CONCLUSION

In patients with MMD, statin therapy was associated with a reduced risk of subsequent stroke. The findings indicate statin treatment may be beneficial for patients with MMD, however the results should be confirmed in randomised controlled trials.

Association between DIAPH1 variant and posterior circulation involvement with Moyamoya disease

Moyamoya disease (MMD) is a chronic and progressive cerebrovascular stenosis or occlusive disease that occurs near Willis blood vessels. The aim of this study was to investigate the mutation of DIAPH1 in Asian population, and to compare the angiographic features of MMD patients with and without the mutation of the DIAPH1 gene. Blood samples of 50 patients with MMD were collected, and DIAPH1 gene mutation was detected. The angiographic involvement of the posterior cerebral artery was compared between the mutant group and the non-mutant group. The independent risk factors of posterior cerebral artery involvement were determined by multivariate logistic regression analysis. DIAPH1 gene mutation was detected in 9 (18%) of 50 patients, including 7 synonymous mutations and 2 missense mutations. However, the incidence of posterior cerebral artery involvement in mutation positive group was very higher than that in mutation negative group (77.8% versus 12%; p = 0.001). There is an association between DIAPH1 mutation and PCA involvement (odds ratio 29.483, 95% confidence interval 3.920-221.736; p = 0.001). DIAPH1 gene mutation is not a major genetic risk gene for Asian patients with moyamoya disease but may play an important role in the involvement of posterior cerebral artery.

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.

Association of RNF213 polymorphism and cortical hyperintensity sign on fluid-attenuated inversion recovery images after revascularization surgery for moyamoya disease: possible involvement of intrinsic vascular vulnerability

A cortical hyperintensity on fluid-attenuated inversion recovery images (FLAIR cortical hyperintensity (FCH)) is an abnormal finding after revascularization surgery for moyamoya disease. This study aimed to investigate the pathophysiology of FCH through genetic analyses of RNF213 p.R4810K polymorphism and perioperative hemodynamic studies using single-photon emission computed tomography. We studied 96 hemispheres in 65 adults and 47 hemispheres in 27 children, who underwent combined direct and indirect revascularization. Early or late FCH was defined when it was observed on postoperative days 0-2 and 6-9, respectively. FCH scores (range: 0-6) were evaluated according to the extent of FCH in the operated hemisphere. FCHs were significantly more prevalent in adult patients than pediatric patients (early: 94% vs. 78%; late: 97% vs. 59%). In pediatric patients, FCH scores were significantly improved from the early to late phase regardless of the RNF213 genotype (mutant median [IQR]: 2 [1-5] vs. 1 [0-2]; wild-type median: 4 [0.5-6] vs. 0.5 [0-1.75]). In adults, FCH scores were significantly improved in patients with the wild-type RNF213 allele (median: 4 [2-5.25] vs. 2 [2, 3]); however, they showed no significant improvement in patients with the RNF213 mutation. FCH scores were significantly higher in patients with symptomatic cerebral hyperperfusion than those without it (early median: 5 [4, 5] vs. 4 [2-5]; late median: 4 [3-5] vs. 3 [2-4]). In conclusion, the RNF213 p.R4810K polymorphism was associated with prolonged FCH, and extensive FCH was associated with symptomatic cerebral hyperperfusion in adult patients with moyamoya disease.

RNF213 Loss-of-Function Promotes Angiogenesis of Cerebral Microvascular Endothelial Cells in a Cellular State Dependent Manner

Enhanced and aberrant angiogenesis is one of the main features of Moyamoya disease (MMD) pathogenesis. The ring finger protein 213 (RNF213) and the variant p.R4810K have been linked with higher risks of MMD and intracranial arterial occlusion development in east Asian populations. The role of RNF213 in diverse aspects of the angiogenic process, such as proliferation, migration and capillary-like formation, is well-known but has been difficult to model in vitro. To evaluate the effect of the RNF213 MMD-associated gene on the angiogenic activity, we have generated RNF213 knockout in human cerebral microvascular endothelial cells (hCMEC/D3-RNF213^-/-) using the CRISPR-Cas9 system. Matrigel-based assay and a tri-dimensional (3D) vascularized model using the self-assembly approach of tissue engineering were used to assess the formation of capillary-like structures. Quite interestingly, this innovative in vitro model of MMD recapitulated, for the first time, disease-associated pathophysiological features such as significant increase in angiogenesis in confluent endothelial cells devoid of RNF213 expression. These cells, grown to confluence, also showed a pro-angiogenic signature, i.e., increased secretion of soluble pro-angiogenic factors, that could be eventually used as biomarkers. Interestingly, we demonstrated that that these MMD-associated phenotypes are dependent of the cellular state, as only noted in confluent cells and not in proliferative RNF213-deficient cells.

RNF213 R4810K Variant in Suspected Unilateral Moyamoya Disease Predicts Contralateral Progression

Background Early-stage unilateral moyamoya disease (MMD) is difficult to discriminate from isolated intracranial atherosclerotic stenosis, and identification of contralateral progression may aid in the diagnosis of MMD. The RNF213 (ring finger protein 213) R4810K variant is a strong genetic susceptibility factor for MMD; however, the role of contralateral progression in unilateral MMD is unknown. Methods and Results Patients who had undergone RNF213 R4810K genotyping with suspected unilateral MMD between January 2017 and August 2021 from 2 tertiary university hospitals were retrospectively reviewed. We compared the clinical features and radiographic outcomes of patients with and without this variant. The risk factors of contralateral progression in patients with suspected unilateral MMD were evaluated. The RNF213 R4810K variant was observed in 72 of 123 patients with suspected unilateral MMD, all of which were heterozygous. The allele frequency of the R4810K variant was significantly higher in the suspected unilateral MMD group compared with the historical control group (29.3% versus 1.2%; P<0.0001). Family history of MMD was significantly more common in patients with the variant than in those without (17% versus 4%; P=0.003). Eleven of 72 patients with the variant developed contralateral progression, whereas only 1 of 51 patients without the variant developed contralateral progression during a median follow-up period of 28 months (log-rank test; P=0.03). The presence of the RNF213 R4810K variant significantly correlated with contralateral progression (adjusted odds ratio, 6.39 [95% CI, 1.11-36.63]; P=0.04). Conclusions Contralateral progression is more likely to occur in patients with suspected unilateral MMD with the RNF213 R4810K variant than in those without the variant. However, because our study used a small sample size, this finding should be carefully interpreted and requires further studies with more patients and longer follow-up periods.

Genome-Wide Association Study of Intracranial Artery Stenosis Followed by Phenome-Wide Association Study

The genetic background of intracranial artery stenosis (ICAS), a major cause of ischemic stroke, remains elusive. We performed the world's first genome-wide association study (GWAS) of ICAS using DNA samples from Japanese subjects, to identify the genetic factors associated with ICAS and their correlation with clinical features. We also conducted a phenome-wide association study (PheWAS) of the top variant identified via GWAS to determine its association with systemic disease. The GWAS involved 408 patients with ICAS and 349 healthy controls and utilized an Asian Screening Array of venous blood samples. The PheWAS was performed using genotypic and phenotypic data of the Biobank Japan Project, which contained information on 46 diseases and 60 quantitative trait data from > 150,000 Japanese individuals. The GWAS revealed that the East Asian-specific functional variant of RNF213, rs112735431 (c.14429G > A, p.Arg4810Lys), was associated with ICAS (odds ratio, 12.3; 95% CI 5.5 to 27.5; P = 7.8 × 10^-10). Stratified analysis within ICAS cases demonstrated that clinical features of those with and without the risk allele were different. PheWAS indicated that high blood pressure and angina were significantly associated with RNF213 rs112735431. The first GWAS of ICAS, which stratifies subpopulations within the ICAS cases with distinct clinical features, revealed that RNF213 rs112735431 was the most significant variant associated with ICAS. Thus, RNF213 rs112735431 shows potential as an important clinical biomarker that characterizes pleiotropic risk in various vascular diseases, such as blood pressure and angina, thereby facilitating personalized medicine for systemic vascular diseases in East Asian populations.