Somatic Mosaicism in the Pathogenesis of de novo Cerebral Arteriovenous Malformations: A Paradigm Shift Implicating the RAS-MAPK Signaling Cascade

Synchronous intracranial arteriovenous malformation and papillary glioneuronal tumour: hypothesis or reality?

Brain arteriovenous malformations (AVM) rarely occur with spatial and/or temporal co-localisation to intracranial neoplasms. Most prior reports describe this association with high-grade gliomas; however, reports of a co-occurrence with low grade gliomas are very rare. It is unclear whether such cases represent a true co-occurrence of separate pathologies or simply an unusually vascular phenotype of the neoplasm. Most such reports pre-date the era of molecularly defined gliomas. We present the first report of the spatial and temporal co-occurrence of an intracranial arteriovenous malformation traversing and within a papillary glioneuronal tumour, molecularly defined by the presence of SLC44A1::PRKCA fusion. This case was successfully managed by resection of both lesions adhering to the principles of AVM surgery. It is possible these exceptionally rare co-occurrences may have common underlying molecular drivers relating to the mitogen activated protein kinase (MAPK) pathway.

Cerebral vascular malformations: pathogenesis and therapy

Cerebral vascular malformations (CVMs), particularly cerebral cavernous malformations and cerebral arteriovenous malformations, pose significant neurological challenges due to their complex etiologies and clinical implications. Traditionally viewed as congenital conditions with structural abnormalities, CVMs have been treated primarily through resection, embolization, and stereotactic radiosurgery. While these approaches offer some efficacy, they often pose risks to neurological integrity due to their invasive nature. Advances in next-generation sequencing, particularly high-depth whole-exome sequencing and bioinformatics, have facilitated the identification of gene variants from neurosurgically resected CVMs samples. These advancements have deepened our understanding of CVM pathogenesis. Somatic mutations in key mechanistic pathways have been identified as causative factors, leading to a paradigm shift in CVM treatment. Additionally, recent progress in noninvasive and minimally invasive techniques, including gene imaging genomics, liquid biopsy, or endovascular biopsies (endovascular sampling of blood vessel lumens), has enabled the identification of gene variants associated with CVMs. These methods, in conjunction with clinical data, offer potential for early detection, dynamic monitoring, and targeted therapies that could be used as monotherapy or adjuncts to surgery. This review highlights advancements in CVM pathogenesis and precision therapies, outlining the future potential of precision medicine in CVM management.

What the Interventional Radiologist Needs to Know about the Genetics of Vascular Anomalies

The purpose of this article is to familiarize the reader with the basic genetics and vascular biology behind the array of vascular anomalies they may encounter in their practice. Individuals with vascular malformations are often referred to multidisciplinary clinics composed of diverse specialists all with the same goal: how to provide the best care possible. The team is typically composed of physicians, nurses, social workers, and technical staff from multiple specialties including diagnostic and interventional radiology, dermatology, hematology/oncology, otolaryngology, plastic surgery, and several additional subspecialties. Imaging plays a crucial role in diagnosis and treatment planning, but increasingly biopsies are needed for more accurate histopathological and genetic information to inform the plan of treatment, as well as for counseling patients and their families on the natural history, heritability, and long-term prognosis of the condition. Understanding the molecular mechanism that gives rise to vascular anomalies is crucial for arriving at the proper diagnosis and choosing among treatment options. As oncological medications are being increasingly repurposed to treat vascular malformations, it is vital for those caring for patients with vascular anomalies to understand how these anomalies develop, and which drug may be appropriate to repurpose for this benign disease.

An Updated Review on the Pathogenesis of Brain Arteriovenous Malformations and Its Therapeutic Targets

Brain arteriovenous malformations (bAVMs) are associated with a high risk of intracerebral hemorrhage, which causes severe complications in patients. Although the genetic factors leading to hereditary bAVMs have been extensively investigated, their pathogenesis are still under study. This review examines updated data on the molecular and genetic aspects of bAVMs, the architecture of microvasculature, the roles of angiogenic factors, and signaling pathways. The compiled information may help us understand the pathogenesis of both sporadic and hereditary bAVMs and develop appropriate preemptive treatment approaches.

De Novo Noninversion Variants Implicated in Sporadic Hemophilia A: A Variant Origin and Timing Study

Sporadic hemophilia A (HA) enables the persistence of HA in the population. F8 gene inversion originates mainly in male germ cells during meiosis. To date, no studies have shown the origin and timing of HA sporadic noninversion variants (NIVs); herein, we assume that HA-sporadic NIVs are generated as a de novo variant. Of the 125 registered families with HA, 22 were eligible for inclusion. We conducted a linkage analysis using F8 gene markers and amplification refractory mutation system-quantitative polymerase chain reaction to confirm the origin of the sporadic NIVs (~0% mutant cells) or the presence of a mosaic variant, which requires further confirmation of the origin in the parent. Nine mothers, four maternal grandmothers, and six maternal grandfathers were confirmed to be the origin of sporadic NIVs, which most likely occurred in the zygote within the first few cell divisions and in single sperm cells, respectively. Three mothers had mosaic variants, which most likely occurred early in postzygotic embryogenesis. All maternal grandparents were free from sporadic NIV. In conclusion, F8 NIVs in sporadic HA were found to be caused primarily by de novo variants. Our studies are essential for understanding the genetic pathogenesis of HA and improving current genetic counseling.

Discovery and Characterization of Ephrin B2 and EphB4 Dysregulation and Novel Mutations in Cerebral Cavernous Malformations: In Vitro and Patient-Derived Evidence of Ephrin-Mediated Endothelial Cell Pathophysiology

Intracranial vascular malformations manifest on a continuum ranging from predominantly arterial to predominantly venous in pathology. Cerebral cavernous malformations (CCMs) are capillary malformations that exist at the midpoint of this continuum. The axon guidance factor Ephrin B2 and its receptor EphB4 are critical regulators of vasculogenesis in the developing central nervous system. Ephrin B2/EphB4 dysregulation has been implicated in the pathogenesis of arterial-derived arteriovenous malformations and vein-based vein of Galen malformations. Increasing evidence supports the hypothesis that aberrant Ephrin B2/EphB4 signaling may contribute to developing vascular malformations, but their role in CCMs remains largely uncharacterized. Evidence of Ephrin dysregulation in CCMs would be important to establish a common link in the pathogenic spectrum of EphrinB2/Ephb4 dysregulation. By studying patient-derived primary CCM endothelial cells (CCMECs), we established that CCMECs are functionally distinct from healthy endothelial cell controls; CCMECs demonstrated altered patterns of migration, motility, and impaired tube formation. In addition to the altered phenotype, the CCMECs also displayed an increased ratio of EphrinB2/EphB4 compared to the healthy endothelial control cells. Furthermore, whole exome sequencing identified mutations in both EphrinB2 and EphB4 in the CCMECs. These findings identify functional alterations in the EphrinB2/EphB4 ratio as a feature linking pathophysiology across the spectrum of arterial, capillary, and venous structural malformations in the central nervous system while revealing a putative therapeutic target.

Advances in the Study of KRAS in Brain Arteriovenous Malformation

BACKGROUND

Brain arteriovenous malformation (bAVM) is an abnormal vascular mass with disordered arteriovenous connection. Endothelial KRAS mutation is common in bAVM. In vivo studies have demonstrated that mutations of KRAS in somatic cells can induce bAVM-like angiogenesis, suggesting that KRAS gene may play a key role in the development and progression of bAVM.

SUMMARY

In this article, we will provide a comprehensive review of action mechanisms of KRAS mutations in the development of bAVM and summarize potential targeting drugs for KRAS mutations in bAVM somatic cells.

KEY MESSAGE

KRAS mutation in human brain endothelial cells is a key driver in the pathogenesis of sporadic cerebral arteriovenous malformations. It is of great clinical importance to explore and summarize the changes in the signaling pathway induced by KRAS mutation, which may provide additional targets for the treatment of sporadic bAVM development.

Network Pharmacology Analysis of Huangqi Jianzhong Tang Targets in Gastric Cancer

Background: The Chinese medicine, Huangqi Jianzhong Tang (HJT), is widely used to treat gastric cancer (GC). In this study, network pharmacological methods were used to analyze the potential therapeutic targets and pharmacological mechanisms of HJT in GC.

Methods: Bioactive components and targets of HJT and GC-related targets were identified using public databases. The protein-protein interaction network of potential targets of HJT in GC was constructed using the Cytoscape plug-in (v3.8.0), CytoHubba. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed, in addition to molecular docking and animal experiments to verify the results of network pharmacology analysis.

Results: A total of 538 GC-related targets were identified. The bioactive components of HJT were selected for drug-likeness evaluation and binomial statistical model screening, which revealed 63 bioactive components and 72 targets. Based on GO enrichment analysis, all targets in the protein-protein interaction network were mainly involved in the response to oxidative stress and neuronal death. Further, KEGG enrichment analysis suggested that the treatment of GC with HJT mainly involved the Wnt signaling pathway, PI3K-Akt signaling pathway, TGF-β signaling pathway, and MAPK signaling pathway, thereby providing insights into the mechanism of the effects of HJT on GC.

Conclusion: This study revealed the potential bioactive components and molecular mechanisms of HJT, which may be useful for the treatment of GC, and provided insights into the development of new drugs for GC.