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Chiari Malformation Type I (CMI) is a congenital malformation diagnosed by MRI findings of at least 5 mm of cerebellar ectopy below the foramen magnum. CM1 is frequently associated with syringomyelia. Herein, we discuss the history of CMI and syringomyelia, including early pathological and surgical studies. We also describe recent investigations into the pathogenesis and pathophysiology of CMI and their practical implications on management and surgical intervention. We also highlight the recent development of the Common Data Elements for CMI, providing a framework for ongoing investigations. Finally, we discuss current controversies of surgical management in CMI.

BACKGROUND Reports of cerebrovascular ischemia and stroke occurring as predominant neurological sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which causes coronavirus disease 2019 (COVID-19), are increasingly evident within the literature. While various pathophysiological mechanisms have been postulated, including hypercoagulability, endothelial invasion, and systemic inflammation, discrete mechanisms for viral neurotropism remain unclear and controversial. OBSERVATIONS The authors present a unique case study of a 64-year-old male with acute COVID-19 infection and acute worsening of previously stable cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a rare heritable arteriopathy due to mutation in the Notch3 gene, which is critical for vascular development and tone. Delayed cranial neuropathies, brainstem fluid-attenuated inversion recovery signal, and enhancement of olfactory and vagus nerves on magnetic resonance neurography in this patient further support viral neurotropism via cranial nerves in addition to cerebral vasculature. LESSONS To the authors’ knowledge, this is the first case in the literature that not only demonstrates the consequences of COVID-19 infection in a patient with altered cerebrovascular autoregulation such as CADASIL but also highlights the tropism of SARS-CoV-2 for (1) cranial nerves as a mode of entry to the central nervous system and (2) vessels as a cause of cerebrovascular ischemia.

Originally approved in 1979, a specific grading classification for central nervous system (CNS) tumors was devised by the World Health Organization (WHO) in an effort to guide cancer treatment and better understand prognosis. These “blue books” have since undergone several iterations based on tumor location, advancements in histopathology, and most recently, diagnostic molecular pathology in its fifth edition. As new research methods have evolved to elucidate complex molecular mechanisms of tumorigenesis, a need to update and integrate these findings into the WHO grading scheme has become apparent. Epigenetic tools represent an area of burgeoning interest that encompasses all non-Mendelian inherited genetic features affecting gene expression, including but not limited to chromatin remodeling complexes, DNA methylation, and histone regulating enzymes. The SWItch/Sucrose non-fermenting (SWI/SNF) chromatin remodeling complex is the largest mammalian family of chromatin remodeling proteins and is estimated to be altered in 20–25% of all human malignancies; however, the ways in which it contributes to tumorigenesis are not fully understood. We recently discovered that CNS tumors with SWI/SNF mutations have revealed an oncogenic role for endogenous retroviruses (ERVs), remnants of exogenous retroviruses that integrated into the germline and are inherited like Mendelian genes, several of which retain open reading frames for proteins whose expression putatively contributes to tumor formation. Herein, we analyzed the latest WHO classification scheme for all CNS tumors with documented SWI/SNF mutations and/or aberrant ERV expression, and we summarize this information to highlight potential research opportunities that could be integrated into the grading scheme to better delineate diagnostic criteria and therapeutic targets.

OBJECTIVEPatients with neurofibromatosis type 1 (NF1) are predisposed to visceral neurofibromas, some of which can progress to premalignant atypical neurofibromas (ANFs) and malignant peripheral nerve sheath tumors (MPNSTs). Though subtotal resection of ANF may prevent malignant transformation and thus deaths with no neural complications, local recurrences require reoperation. The aim of this study was to assess the surgical morbidity associated with marginal resection of targeted ANF nodules identified via preoperative serial volumetric MRI and 18F-FDG-PET imaging.METHODSThe authors analyzed clinical outcomes of 16 NF resections of 21 tumors in 11 NF1 patients treated at the NIH Clinical Center between 2008 and 2018. Preoperative volumetric growth rates and 18F-FDG-PET SUVMax (maximum standardized uptake value within the tumor) of the target lesions and any electromyographic or nerve conduction velocity abnormalities of the parent nerves were measured and assessed in tandem with postoperative complications, histopathological classification of the resected tumors, and surgical margins through Dunnett’s multiple comparisons test and t-test. The surgical approach for safe marginal resection of ANF was also described.RESULTSEleven consecutive NF1 patients (4 male, 7 female; median age 18.5 years) underwent 16 surgical procedures for marginal resections of 21 tumors. Preoperatively, 13 of the 14 (93%) sets of serial MRI studies and 10 of the 11 (91%) 18F-FDG-PET scans showed rapid growth (≥ 20% increase in volume per year) and avidity (SUVMax ≥ 3.5) of the identified tumor, respectively (median tumor size 48.7 cm3; median growth rate 92% per year; median SUVMax 6.45). Most surgeries (n = 14, 88%) resulted in no persistent postoperative parent nerve–related complications, and to date, none of the resected tumors have recurred. The median length of postoperative follow-up has been 2.45 years (range 0.00–10.39 years). Histopathological analysis confirmed significantly greater SUVMax among the ANFs (6.51 ± 0.83, p = 0.0042) and low-grade MPNSTs (13.8, p = 0.0001) than in benign neurofibromas (1.9).CONCLUSIONSThis report evaluates the utility of serial imaging (MRI and 18F-FDG-PET SUVMax) to successfully detect ANF and demonstrates that safe, fascicle-sparing gross-total, extracapsular resection of ANF is possible with the use of intraoperative nerve stimulation and microdissection of nerve fascicles.

The integration of genomic testing into clinical care enables the use of individualized approaches to the management of rare diseases. We describe the use of belzutifan, a potent and selective small-molecule inhibitor of the protein hypoxia-inducible factor 2α (HIF2α), in a patient with polycythemia and multiple paragangliomas (the Pacak-Zhuang syndrome). The syndrome was caused in this patient by somatic mosaicism for an activating mutation in

Understanding physiologic and pathologic central nervous system function depends on our ability to map the entire

Pheochromocytomas, arising from chromaffin cells, produce catecholamines, epinephrine and norepinephrine. The tumor biochemical phenotype is defined by which of these exerts the greatest influence on the cardiovascular system when released into circulation in high amounts. Action on the heart and vasculature can cause potentially lethal arrhythmias, often in the setting of comorbid blood pressure derangements. In a review of electrocardiograms obtained on pheochromocytoma patients (n = 650) treated at our institution over the last decade, severe and refractory sinus tachycardia, atrial fibrillation, and ventricular tachycardia were found to be the most common or life-threatening catecholamine-induced tachyarrhythmias. These arrhythmias, arising from catecholamine excess rather than from a primary electrophysiologic substrate, require special considerations for treatment and complication avoidance. Understanding the synthesis and release of catecholamines, the adrenoceptors catecholamines bind to, and the cardiac and vascular response to epinephrine and norepinephrine underlies optimal management in catecholamine-induced tachyarrhythmias.

Human endogenous retroviruses (HERVs), which are critical to normal embryologic development and downregulated during normal maturation, have been implicated in a variety of cancers. Abnormal persistent production of HERVs has been suggested to play a role in oncogenesis and to confer stem cell properties to cells. We recently demonstrated that the most recently incorporated HERV element (HERV-K HML-2) has been associated with the pathogenesis of the embryonal atypical teratoid rhabdoid tumor (AT/RT), shifting our understanding of embryonal tumor development. HML-2 expression is vital for proper human development and its expression is suppressed via methylation or chromatin remodeling as cells differentiate. We previously found that dysfunctional chromatin remodeling due to loss of SMARCB1 expression induces HML-2 envelope (env) expression, impairing cellular differentiation and migration, and facilitating tumor growth in AT/RT. Epigenetic dysregulation in other embryonal tumors with concomitant expression of stem-cell markers may facilitate HML-2 expression. Future studies could utilize HML-2 as potential diagnostic criteria, use its expression as a treatment biomarker, and investigate the efficacy of therapies targeting cells with high HML-2 expression.

We recently described a previously unknown trans-tentorial venous system (TTVS) connecting venous drainage throughout the brain in humans. Prior to this finding, it was believed that the embryologic tentorial plexus regresses, resulting in a largely avascular tentorium. Our finding contradicted this understanding and necessitated further investigation into the development of the newly described TTVS. Herein we sought to investigate mice as a model to study the development of this system. First, using vascular casting and ex vivo micro-computed tomography (micro-CT), we demonstrate that this TTVS is conserved in adult mice. Next, using high-resolution magnetic resonance imaging (MRI), we found the primitive tentorial venous plexus in murine embryo at day 14.5. We also found that, at this embryologic stage, the tentorial plexus drains the choroid plexus. Finally, using vascular casting and micro-CT, we found that the TTVS is the dominant venous drainage in the early postnatal period (P8). Herein, we demonstrate that the TTVS is conserved between mice and humans and present a longitudinal study of its development. In addition, our findings establish mice as a translational model for further study of this newly described system and its relationship to intracranial physiology.

Atypical Teratoid Rhabdoid Tumor (AT/RT) is a rare pediatric central nervous system cancer often characterized by deletion or mutation of SMARCB1, a tumor suppressor gene. In this study, we found that SMARCB1 regulates Human Endogenous Retrovirus K (HERV-K, subtype HML-2) expression. HML-2 is a repetitive element scattered throughout the human genome, encoding several intact viral proteins that have been associated with stem cell maintenance and tumorigenesis. We found HML-2 env expression in both the intracellular and extracellular compartments in all AT/RT cell lines (n = 4) and in 95% of AT/RT patient tissues (n = 37) evaluated. SMARCB1 knock-down in neural stem cells (NSCs) led to an upregulation of HML-2 transcription. We found that SMARCB1 binds adjacent to the HML-2 promoter, repressing its transcription via chromatin immunoprecipitation; restoration of SMARCB1 expression in AT/RT cell lines significantly downregulated HML-2 expression. Further, targeted downregulation of HML-2 transcription via CRISPR-dCas9 coupled with suppressor proteins led to cellular dispersion, decreased proliferation, and cell death in vitro. HML-2 knock-down with shRNA, siRNA, and CRISPR-dCas9 significantly decreased Ras expression as measured by qRT-PCR, suggesting that HML-2 modulates MAPK/ERK signaling in AT/RT cells. Overexpression of NRAS was sufficient to restore cellular proliferation, and MYC, a transcription factor downstream of NRAS, was bound to the HERV-K LTR significantly more in the absence of SMARCB1 expression in AT/RT cells. We show a mechanism by which these undifferentiated tumors remain pluripotent, and we demonstrate that their formation is aided by aberrant HML-2 activation, which is dependent on SMARCB1 and its interaction with MYC.

Background Glioblastoma survival remains unchanged despite continuing therapeutic innovation. Herein, we aim to (i) develop chimeric antigen receptor (CAR) T cells with a specificity to a unique antigen, carbonic anhydrase IX (CAIX), which is expressed in the hypoxic microenvironment characteristic of glioblastoma, and (ii) demonstrate its efficacy with limited off-target effects. Methods First we demonstrated expression of CAIX in patient-derived glioblastoma samples and available databases. CAR T cells were generated against CAIX and efficacy was assessed in 4 glioblastoma cell lines and 2 glioblastoma stem cell lines. Cytotoxicity of anti-CAIX CAR T cells was assessed via interferon gamma, tumor necrosis factor alpha, and interleukin-2 levels when co-cultured with tumor cells. Finally, we assessed efficacy of direct intratumoral injection of the anti-CAIX CAR T cells on an in vivo xenograft mouse model using the U251 luciferase cell line. Tumor infiltrating lymphocyte analyses were performed. Results We confirm that CAIX is highly expressed in glioblastoma from patients. We demonstrate that CAIX is a suitable target for CAR T-cell therapy using anti-CAIX CAR T cells against glioblastoma in vitro and in vivo. In our mouse model, a 20% cure rate was observed without detectable systemic effects. Conclusions By establishing the specificity of CAIX under hypoxic conditions in glioblastoma and highlighting its efficacy as a target for CAR T-cell therapy, our data suggest that anti-CAIX CAR T may be a promising strategy to treat glioblastoma. Direct intratumoral injection increases anti-CAIX CAR T-cell potency while limiting its off-target effects.

Elevated expression of lncRNA H19 (H19) in the setting of hypoxia has been implicated as a promising therapeutic target for various cancers. However, little is known about the impact and underlying mechanism of H19 in ischemic brain stroke. This study found that H19 levels were elevated in the serum of stroke patients, as well as in the ischemic penumbra of rats with middle cerebral artery occlusion/reperfusion (MCAO/R) injury and neuronal cells with oxygen glucose deprivation (OGD). Further, knockdown of H19 with siRNA alleviated cell apoptosis in OGD neuronal cells, and inhibition of H19 in MCAO/R rats significantly decreased neurological deficit, brain infarct volume and neuronal apoptosis. Lastly, with gain and loss of function studies, dual luciferase reported assay, RNA immunoprecipitation (RIP) and pull-down experiments, we demonstrated the dual competitive interaction of miR-19a with H19 and the 3'-UTR of Id2 mRNA, resulting in the identification of the H19-miR-19a-Id2 axis. With biological studies, we also revealed that H19-miR-19a-Id2 axis modulated hypoxia induced neuronal apoptosis. This study demonstrates that the identified H19-miR-19a-Id2 axis plays a critical role in hypoxia induced neuronal apoptosis, and blocking this axis may serve as a novel therapeutic strategy for ischemic brain injury.

Previously we identified the p.Thr61Ile mutation in coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2) in a Chinese family with autosomal dominant Parkinson’s disease. But the mechanism is still unclear. In this study, we explored the effects of CHCHD2 p.Thr61Ile mutation in cells and its association with coiled-coil-helix-coiled-coil-helix domain containing 10 (CHCHD10). We found that overexpression of Parkinson’s disease–associated T61I mutant CHCHD2 did not produce mitochondrial dysfunction. Rather, its protective effect from stress was abrogated. And, the level of the CHCHD2 protein and mRNA in patient fibroblasts was not significantly different from control. In addition, CHCHD2 T61I mutation caused increased interaction with CHCHD10 and reduced CHCHD10 level. The mitochondrial ultrastructural alterations in CHCHD2 T61I mutant patient fibroblasts are similar to that of CHCHD10 mutations. We therefore propose that CHCHD10 is involved in the development of Parkinson’s disease caused by CHCHD2 loss-of-function mutation p.T61I.

Pediatric medulloblastoma (MB) is the most common pediatric brain tumor with varying prognoses depending on the distinct molecular subtype. The four consensus subgroups are WNT, Sonic hedgehog (SHH), Group 3, and Group 4, which underpin the current 2021 WHO classification of MB. While the field of knowledge for treating this disease has significantly advanced over the past decade, a deeper understanding is still required to improve the clinical outcomes for pediatric patients, who are often vulnerable in ways that adult patients are not. Here, we discuss how recent insights into the pathogenesis of pediatric medulloblastoma have directed current and future research. This review highlights new developments in understanding the four molecular subtypes’ pathophysiology, epigenetics, and therapeutic targeting. In addition, we provide a focused discussion of recent developments in imaging, and in the surgery, chemotherapy, and radiotherapy of pediatric medulloblastoma. The article includes a brief explanation of healthcare costs associated with medulloblastoma treatment.

Mutations in EPAS1, encoding hypoxia-inducible factor-2α (HIF-2α), were previously identified in a syndrome of multiple paragangliomas, somatostatinoma, and polycythemia. HIF-2α, when dimerized with HIF-1β, acts as an angiogenic transcription factor. Patients referred to the NIH for new, recurrent, and/or metastatic paraganglioma or pheochromocytoma were confirmed for EPAS1 gain-of-function mutation; imaging was evaluated for vascular malformations. We evaluated the Epas1A529V transgenic syndrome mouse model, corresponding to the mutation initially detected in the patients (EPAS1A530V), for vascular malformations via intravital 2-photon microscopy of meningeal vessels, terminal vascular perfusion with Microfil silicate polymer and subsequent intact ex vivo 14T MRI and micro-CT, and histologic sectioning and staining of the brain and identified pathologies. Further, we evaluated retinas from corresponding developmental time points (P7, P14, and P21) and the adult dura via immunofluorescent labeling of vessels and confocal imaging. We identified a spectrum of vascular malformations in all 9 syndromic patients and in all our tested mutant mice. Patient vessels had higher variant allele frequency than adjacent normal tissue. Veins of the murine retina and intracranial dura failed to regress normally at the expected developmental time points. These findings add vascular malformation as a new clinical feature of EPAS1 gain-of-function syndrome., We discovered vascular malformations due to failure of developmental vascular regression in patients with EPAS1 gain-of-function mutation syndrome and the corresponding transgenic mouse model.

Quantifying terabyte-scale multi-modal human and animal imaging data requires scalable analysis tools. We developed CloudReg, an open-source, automatic, terabyte-scale, cloud-based image analysis pipeline that pre-processes and registers cross-modal volumetric datasets with artifacts via spatially-varying polynomial intensity transform. CloudReg accurately registers the following datasets to their respective atlases: in vivo human and ex vivo macaque brain magnetic resonance imaging, ex vivo mouse brain micro-computed tomography, and cleared murine brain light-sheet microscopy.

The genetic basis and corresponding clinical relevance of prolactinomas remain poorly understood. Here, we perform whole genome sequencing (WGS) on 21 patients with prolactinomas to detect somatic mutations and then validate the mutations with digital polymerase chain reaction (PCR) analysis of tissue samples from 227 prolactinomas. We identify the same hotspot somatic mutation in splicing factor 3 subunit B1 (SF3B1R625H) in 19.8% of prolactinomas. These patients with mutant prolactinomas display higher prolactin (PRL) levels (p = 0.02) and shorter progression-free survival (PFS) (p = 0.02) compared to patients without the mutation. Moreover, we identify that the SF3B1R625H mutation causes aberrant splicing of estrogen related receptor gamma (ESRRG), which results in stronger binding of pituitary-specific positive transcription factor 1 (Pit-1), leading to excessive PRL secretion. Thus our study validates an important mutation and elucidates a potential mechanism underlying the pathogenesis of prolactinomas that may lead to the development of targeted therapeutics., The genetic basis of prolactinomas remains poorly understood. Here, the authors find a recurrent hotspot somatic mutation in the splicing factor 3 subunit B1 (SF3B1R625H) in prolactinomas, and show that this mutation causes aberrant splicing of ESRRG mRNA leading to up-regulation of prolactin.

BACKGROUND AND PURPOSE: A new transtentorial venous system consisting of medial, intermediate, and lateral tentorial veins, connecting infra- and supratentorial compartments, was recently shown in 2 cadaver dissections and 2 patient scans. We sought to characterize the venous patterns within the tentorium and their relation to measures of skull development in a cohort of healthy adults. MATERIALS AND METHODS: We retrospectively reviewed tentorial venous anatomy of the head using CTA/CTV performed for routine care or research purposes in 238 patients. Included studies had adequate contrast opacification of venous structures and a section thickness of ≤2 mm; we excluded cases with space-occupying lesions and vascular pathologies. Tentorial angle, dural sinus configurations, and measures of skull base development were assessed as predictors of tentorial venous anatomy variation via Cramér V association, the binary encoded Pearson correlation, and nearest-point algorithm with the Euclidean distance metric for clustering. RESULTS: Tentorial vein development was related to the ringed configuration of the tentorial sinuses (P

Chimeric antigen receptor (CAR)-engineered T cells represent a promising modality for treating glioblastoma. Recently, we demonstrated that CAR-T cells targeting carbonic anhydrase IX (CAIX), a protein involved in HIF-1a hypoxic signaling, is a promising CAR-T cell target in an intracranial murine glioblastoma model. Anti-CAIX CAR-T cell therapy is limited by its suboptimal activation within the tumor microenvironment. LB-100, a small molecular inhibitor of protein phosphatase 2A (PP2A), has been shown to enhance T cell anti-tumor activity through activation of the mTOR signaling pathway. Herein, we investigated if a treatment strategy consisting of a combination of LB-100 and anti-CAIX CAR-T cell therapy produced a synergistic anti-tumor effect. Our studies demonstrate that LB-100 enhanced anti-CAIX CAR-T cell treatment efficacy in vitro and in vivo. Our findings demonstrate the role of LB-100 in augmenting the cytotoxic activity of anti-CAIX CAR-T cells and underscore the synergistic therapeutic potential of applying combination LB-100 and CAR-T Cell therapy to other solid tumors.

Pheochromocytomas, arising from chromaffin cells, produce catecholamines, epinephrine and norepinephrine. The tumor biochemical phenotype is defined by which of these exerts the greatest influence on the cardiovascular system when released into circulation in high amounts. Action on the heart and vasculature can cause potentially lethal arrhythmias, often in the setting of comorbid blood pressure derangements. In a review of electrocardiograms obtained on pheochromocytoma patients (n = 650) treated at our institution over the last decade, severe and refractory sinus tachycardia, atrial fibrillation, and ventricular tachycardia were found to be the most common or life-threatening catecholamine-induced tachyarrhythmias. These arrhythmias, arising from catecholamine excess rather than from a primary electrophysiologic substrate, require special considerations for treatment and complication avoidance. Understanding the synthesis and release of catecholamines, the adrenoceptors catecholamines bind to, and the cardiac and vascular response to epinephrine and norepinephrine underlies optimal management in catecholamine-induced tachyarrhythmias.

Atypical teratoid rhabdoid tumor (ATRT) is a pediatric brain tumor with a high mortality rate characterized by mutations in/ deletions of SWI/SNF matrix-associated actin-dependent regulator of chromatin sub-family B member 1 (SMARCB1). We previously showed that loss of SMARCB1 causes up-regulation and release of HML-2 subfamily of human endogenous retrovirus K envelope protein (HML-2 ENV), resulting in maintenance of pluripotency. Here, we investigated intracellular trafficking and release of HML-2 ENV. Further, we demonstrate two potential therapeutic strategies to decrease intracellular HML-2 ENV: 1) inhibition of calcium influx by ouabain, a cardiac glycoside toxic to neural stem cells, and 2) targeted inhibition of cyclin-dependent kinase 5 (CDK5), which is restricted to neurons by p35, its activator protein, by TP5. ATRT cell lines and tumor tissue obtained from patients were confirmed for SMARCB1 loss and increased HML-2 ENV. Cell viability and intracellular HML-2 ENV concentration were measured after treatment with ouabain and TP5 (CDK5 antagonist). We evaluated the calcium-mediated effect of ouabain on HML-2 intracellular concentration by treating the cells with ouabain, the calcium chelators calcimycin and EGTA, and calpeptin, a calpain inhibitor, which activates CDK5, and measuring HML-2 ENV and p35. We evaluated HML-2 ENV for a CDK5 consensus phosphorylation site and performed co-immunoprecipitation to evaluate direct interaction. We evaluated activity of CDK5 in ATRT cell lines by autoradiography. Both Ouabain and TP5 caused a decrease in cell viability in a dose-dependent manner. Further, ouabain treatment decreased HML-2 ENV intracellular concentration. We found that HML-2 ENV contains a consensus phosphorylation site for CDK5. We discovered that HML-2 ENV was bound to CDK5. We established that ATRT cell lines had hyperactive CDK5. Finally, we established that the effect of ouabain on HML-2 ENV was due to indirect inhibition of calcium-mediated activation of calpain and thus CDK5.

Primary adenocarcinoma of the small intestine comprises one of the rarest gastrointestinal malignancies. Further, the terminal ileum is very seldom implicated. This entity occurs sporadically and evades traditional colonoscopic evaluation in which the terminal ileum is not visualized. Herein, a case of interval development of primary terminal ileal adenocarcinoma over a 2-year period is reported as followed by direct endoscopic and colonoscopic visualization. This case demonstrates cecal involvement not found on initial evaluation without the provision of terminal ileum intubation. Relevant guidelines regarding the evaluation of the terminal ileum in routine colonoscopy are reviewed.

Hepatocellular carcinoma (HCC) is a terminal, yet preventable, outcome of untreated infection with hepatitis B virus (HBV). HBV is endemic in many areas of Latin America and the Caribbean, including Haiti. Haitians have the highest incidence of liver cancer among Caribbean immigrants. Unfortunately, many of these patients are not screened, despite current guidelines. As HBV is treatable, screening of high-risk populations is crucial to early intervention and prevention of poor outcomes. We highlight the case of a young Haitian male immigrant who presented with unintentional weight loss and epigastric pain and found to have HCC associated with HBV. Despite chemotherapy, the patient died 15 months after diagnosis. Increased awareness of HBV among patients from high-incidence countries may result in early recognition of this disease and reduced morbidity and mortality from devastating complications.

A syndrome of multiple paragangliomas/pheochromocytomas, somatostatinoma, and polycythemia due to somatic mosaic gain-of-function mutation of EPAS1, encoding HIF-2α, was previously described. HIF-2α has been implicated in endochondral and intramembranous ossification. Abnormal bone growth of the skull base may lead to Chiari malformation type I. We report two cases of EPAS1 gain-of-function mutation syndrome with Chiari malformation and developmental skull base anomalies. Patients were referred to the Section on Medical Endocrinology, Eunice Kennedy Shriver NICHD, NIH for evaluation of recurrent and metastatic paragangliomas or pheochromocytoma. The syndrome was confirmed genetically by identification of the functional EPAS1 gain-of-function mutation in the resected tumors and circulating leukocytes. Both patients were confirmed for characteristics of EPAS1 gain-of-function mutation syndrome by complete blood count (CBC), plasma biochemistry, and computed tomography (CT) of the abdomen and pelvis. Chiari malformation type I and abnormal bony development of the posterior fossa was found on MRI and CT of the head. The present study implicates EPAS1 mutations in abnormal posterior fossa development resulting in Chiari malformation type I.

We previously identified a novel syndrome in patients characterized by paraganglioma, somatostatinoma, and polycythemia. In these patients, polycythemia occurs long before any tumor develops, and tumor removal only partially corrects polycythemia, with recurrence occurring shortly after surgery. Genetic mosaicism of gain-of-function mutations of the EPAS1 gene (encoding HIF2&alpha, ) located in the oxygen degradation domain (ODD), typically p.530&ndash, 532, was shown as the etiology of this syndrome. The aim of the present investigation was to demonstrate that these mutations are necessary and sufficient for the development of the symptoms. We developed transgenic mice with a gain-of-function Epas1A529V mutation (corresponding to human EPAS1A530V), which demonstrated elevated levels of erythropoietin and polycythemia, a decreased urinary metanephrine-to-normetanephrine ratio, and increased expression of somatostatin in the ampullary region of duodenum. Further, inhibition of HIF2&alpha, with its specific inhibitor PT2385 significantly reduced erythropoietin levels in the mutant mice. However, polycythemia persisted after PT2385 treatment, suggesting an alternative erythropoietin-independent mechanism of polycythemia. These findings demonstrate the vital roles of EPAS1 mutations in the syndrome development and the great potential of the Epas1A529V animal model for further pathogenesis and therapeutics studies.

Background Described variations of tentorial venous anatomy impact surgical sectioning of the tentorium in skull base approaches; however, described configurations do not consistently explain postoperative complications. To understand the outcomes of 2 clinical cases we studied the tentorial venous anatomy of 2 cadavers. Methods The venous anatomy of the tentorium isolated in 2 uninjected fresh cadaver head specimens with preserved bridging veins was observed by transillumination before and after methylene blue injection of the dural sinuses and tentorial veins. Our findings in cadavers were applied to explain the clinical and radiologic (magnetic resonance imaging and computed tomographic venography) findings in the 2 cases presented. Results A consistent transtentorial venous system, arising from transverse and straight sinuses, communicating with supra- and infratentorial bridging veins was seen in the cadaver and patient radiography (magnetic resonance imaging and computed tomographic venography). Our first patient had a cerebellar venous infarct from compromise of the venous drainage from the adjacent brain after ligation of a temporal lobe bridging vein to the tentorium. Our second patient suffered no clinical effects from bilateral transverse sinus occlusion due to drainage through the accessory venous system within the tentorium. Conclusions Herein, we elaborate on transtentorial venous anatomy. These veins, previously reported to obliterate in completed development of the tentorium, remain patent with consistent observed configuration. The same transtentorial venous system was observed in both cases and provided insight to their outcomes. These findings emphasize the importance of the transtentorial venous system physiologically and in surgical approaches.

We previously identified a novel syndrome in patients characterized by paraganglioma, somatostatinoma, and polycythemia. In these patients, polycythemia occurs long before any tumor develops, and tumor removal only partially corrects polycythemia, with recurrence occurring shortly after surgery. Genetic mosaicism of gain-of-function mutations of the EPAS1 gene (encoding HIF2α) located in the oxygen degradation domain (ODD), typically p.530–532, was shown as the etiology of this syndrome. The aim of the present investigation was to demonstrate that these mutations are necessary and sufficient for the development of the symptoms. We developed transgenic mice with a gain-of-function Epas1A529V mutation (corresponding to human EPAS1A530V), which demonstrated elevated levels of erythropoietin and polycythemia, a decreased urinary metanephrine-to-normetanephrine ratio, and increased expression of somatostatin in the ampullary region of duodenum. Further, inhibition of HIF2α with its specific inhibitor PT2385 significantly reduced erythropoietin levels in the mutant mice. However, polycythemia persisted after PT2385 treatment, suggesting an alternative erythropoietin-independent mechanism of polycythemia. These findings demonstrate the vital roles of EPAS1 mutations in the syndrome development and the great potential of the Epas1A529V animal model for further pathogenesis and therapeutics studies.

Elevated expression of lncRNA H19 (H19) in the setting of hypoxia has been implicated as a promising therapeutic target for various cancers. However, little is known about the impact and underlying mechanism of H19 in ischemic brain stroke. This study found that H19 levels were elevated in the serum of stroke patients, as well as in the ischemic penumbra of rats with middle cerebral artery occlusion/reperfusion (MCAO/R) injury and neuronal cells with oxygen glucose deprivation (OGD). Further, knockdown of H19 with siRNA alleviated cell apoptosis in OGD neuronal cells, and inhibition of H19 in MCAO/R rats significantly decreased neurological deficit, brain infarct volume and neuronal apoptosis. Lastly, with gain and loss of function studies, dual luciferase reported assay, RNA immunoprecipitation (RIP) and pull-down experiments, we demonstrated the dual competitive interaction of miR-19a with H19 and the 3’-UTR of Id2 mRNA, resulting in the identification of the H19-miR-19a-Id2 axis. With biological studies, we also revealed that H19-miR-19a-Id2 axis modulated hypoxia induced neuronal apoptosis. This study demonstrates that the identified H19-miR-19a-Id2 axis plays a critical role in hypoxia induced neuronal apoptosis, and blocking this axis may serve as a novel therapeutic strategy for ischemic brain injury.

IMPORTANCE: Patients with the EPAS1 gain-of-function mutation syndrome (or Pacak-Zhuang syndrome) present with multiple paragangliomas or pheochromocytomas, duodenal somatostatinoma, polycythemia, headaches, and sometimes diminished visual acuity at an early age. The characteristic phenotype and known genetic cause of the syndrome provide an opportunity to study the role of hypoxia-inducible factor 2α (HIF-2α) in oxygen sensing, development in regions of physiologic hypoxia, and other pathological processes. OBJECTIVES: To describe the ocular lesions in EPAS1 gain-of-function mutation syndrome and to establish whether early-onset diminished visual acuity is developmental or associated with long-term physiologic sequelae of the syndrome. DESIGN, SETTING, AND PARTICIPANTS: This clinical case series with a transgenic murine model study was conducted from July 2013 to June 2019. Participants were 3 patients referred by their primary care physicians to the National Institutes of Health for evaluation of recurrent and metastatic paragangliomas or pheochromocytomas accompanied by polycythemia. The syndrome and somatic mosaicism in patients were confirmed by the identification of gain-of-function mutations in the EPAS1 gene in resected tumors and other tissues. MAIN OUTCOMES AND MEASURES: Ocular findings in patients with EPAS1 gain-of-function mutation syndrome. RESULTS: A total of 3 patients (mean [SD] age, 29 [6.2] years) with confirmed ocular abnormalities were included in the study. Increased contrast accumulation at the posterior aspect of the globe was seen bilaterally on magnetic resonance imaging scans in all patients. Ophthalmoscopy images demonstrated fibrosis overlying the optic disc, tortuous and dilated retinal vessels, and retinal pigment epithelium changes. Optic disc edema and retinal exudates were also seen. Fluorescein angiography images showed leakage of dye from postcapillary venules surrounding the optic disc and highlighted aberrant retinal vascular patterns. Enhanced-depth imaging optical coherence tomography images showed substantial thickening of the choroid and dilation of choroidal vessels. The ocular features of the syndrome were confirmed with a transgenic model of mice with gain-of-function Epas1(A529V) mutation. CONCLUSIONS AND RELEVANCE: In this case series, HIF-2α and hypoxia signaling was found to have a role in vessel development within the choroid and retina, indicating that the marked permanent choroidal thickening and tortuous and dilated veins seen in the choroid and retina in patients with EPAS1 gain-of-function mutation syndrome were suggestive of the persistence of venous elements within the developing mesenchyme. These findings may explain other eye and vascular abnormalities whose pathogenesis remains unclear.

Patients with von Hippel Lindau (VHL) disease develop multiple central nervous system hemangioblastomas (HB). The surgical resection of VHL-HBs is the standard of clinical care when these HBs become symptomatic due to tumor growth, edema, or cyst formation. VHL-HBs frequently present at the obex of the brainstem, making this a challenging surgical problem. Here, we present a case of a large symptomatic brainstem VHL-HB that was resected using a dorsal midline approach and midline myelotomy. This 35-year-old man with VHL disease and multiple prior resections of cerebellar hemangioblastomas presented with progressive bilateral upper extremity weakness, ataxia, and dysphagia. The accompanying two-dimensional (2D) video demonstrates the key techniques for resection of this brainstem hemangioblastoma, including recognizing the pial presentation, sharp pial/subpial dissection, and en bloc removal. Subsequently, we discuss circumferential dissection, identification, and division of feeding vessels. We also demonstrate key maneuvers to recognize and divide the main arterial pedicle while preserving the anterior spinal artery. The patient tolerated the resection without complication and the patient was discharged home after 6 days at his baseline neurologic function. This work was supported by the Intramural Research Program of the National Institutes of Health.The link to the video can be found at: https://youtu.be/mb2VqcLpxDQ.

The need for novel therapies for glioblastoma multiforme (GBM) is well established. Chimeric antigen receptor (CAR)-engineered T cells represent a promising cancer treatment modality for treating GBM. However, CAR-T therapy has limitations, such as low penetration into solid tumors and short duration of CAR-T survival. Protein phosphatase 2A (PP2A) inhibition has been implicated in enhancing T cell anti-tumor activity. LB-100 is a novel, first-in-class, small molecule inhibitor of PP2A recently shown in a Phase I trial to be well-tolerated at doses resulting in stabilization of progressive solid tumors. We set out to overcome limitations of CAR-T therapy by activating the mTOR signaling pathway through inhibition of PP2A by LB-100. GBM highly expresses CAIX due to increased hypoxia signaling. Thus, antitumor CAIX-specific CAR T cells were developed and tested against GBM in vitro and in vivo. CAR-T cells displayed GBM cells cytotoxicity and increased IFN-γ, TNF-α, and IL-2 production. Intra-tumor injection of the CAR-T cells into an intracranial GBM xenograft mouse model efficiently suppressed the tumor growth. We found that PP2A inhibition by LB-100 further enhanced CAIX CAR-T activity and significantly prolonged mouse survival. Herein we demonstrate that CAIX represents a viable target for CAR-T cells and inhibition of PP2A enhances CAR-T efficacy against GBM. Targeting PP2A via inhibition with LB-100 may be a promising therapeutic strategy to improve CAR-T efficacy in other solid tumors. Citation Format: Jing Cui, Qi Zhang, Qi Song, Herui Wang, Pauline Dmitriev, Mitchell Sun, Jared S. Rosenblum, Kaiyong Yang, John Kovach, Mark R. Gilbert, Zhengping Zhuang. Targeting PP2A with LB100 enhances efficacy of CAIX CAR-T cells against GBM [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2260.

BACKGROUND: The need for novel therapies for GBM treatment is well established. While chimeric antigen receptor (CAR)-engineered T cells represent a promising cancer treatment modality, highly expressed unique cell surface antigens are essential. We postulated that tumor-specific surface antigens related to hypoxia signaling may have potential. Carbonic Anhydrase IX (CAIX) is active in settings of unbalanced pH driving proton transport to the extracellular medium in response to decreased oxygen tension. We provide evidence that CAIX is highly expressed in GBM and thus a potentially suitable target which we investigated using CAIX-specific CAR-T cells against GBM cells. METHODS: Patient GBM tissues were evaluated for CAIX protein expression. Antitumor CAIX-specific CAR T cells were developed and tested against four GBM cell lines: U251, LN 229, T98G, and A172. Cytotoxicity of CAIX CAR-T cells was assessed using the levels of IFN-γ, TNF-α, and IL-2 released when co-cultured with tumor cells. Direct intra-tumor injection of CAR-T cells into intracranial GBM xenograft mouse model was used for in vivo testing. RESULTS: We confirmed high expression of CAIX in of human GBM. The viral construct of CAIX-specific CAR-T cells generated was tested against GBM cell lines. In vitro, CAIX-specific CAR-T cells displayed enhanced GBM cells cytolysis and increased IFN-γ, TNF-α, and IL-2 production. The CAR-T cells showed a specific CAIX-dependent recognition of GBM cells. Direct intra-tumor injection of the CAR-T cells into an intracranial GBM xenograft mouse model efficiently suppressed the growth of GBM cells and significantly prolonged mouse survival. In approximately 20%, CAIX specific CAR-T cells completely eradicated GBM tumors. CONCLUSIONS: The present study demonstrates the specificity of CAIX under hypoxic conditions in GBM. The results also show that CAIX represents a viable target for CAR-T cells and may be a promising strategy to treat GBM.