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Schwannoma tumours typically arise on the eighth cranial nerve and are mostly caused by loss of the tumour suppressor Merlin (NF2). There are no approved chemotherapies for these tumours and the surgical removal of the tumour carries a high risk of damage to the eighth or other close cranial nerve tissue. New treatments for schwannoma and other NF2-null tumours such as meningioma are urgently required. Using a combination of human primary tumour cells and mouse models of schwannoma, we have examined the role of the Hippo signalling pathway in driving tumour cell growth. Using both genetic ablation of the Hippo effectors YAP and TAZ as well as novel TEAD palmitoylation inhibitors, we show that Hippo signalling may be successfully targeted in vitro and in vivo to both block and, remarkably, regress schwannoma tumour growth. In particular, successful use of TEAD palmitoylation inhibitors in a preclinical mouse model of schwannoma points to their potential future clinical use. We also identify the cancer stem cell marker aldehyde dehydrogenase 1A1 (ALDH1A1) as a Hippo signalling target, driven by the TAZ protein in human and mouse NF2-null schwannoma cells, as well as in NF2-null meningioma cells, and examine the potential future role of this new target in halting schwannoma and meningioma tumour growth.

Introduction There are a number of prognostic markers (methylation, CDKN2A/B) described to be useful for the stratification of meningiomas. However, there are currently no clinically validated biomarkers for the preoperative prediction of meningioma grade, which is determined by the histological analysis of tissue obtained from surgery. Accurate preoperative biomarkers would inform the pre-surgical assessment of these tumours, their grade and prognosis and refine the decision-making process for treatment. This review is focused on the more controversial grade II tumours, where debate still surrounds the need for adjuvant therapy, repeat surgery and frequency of follow up. Methods We evaluated current literature for potential grade II meningioma clinical biomarkers, focusing on radiological, biochemical (blood assays) and immunohistochemical markers for diagnosis and prognosis, and how they can be used to differentiate them from grade I meningiomas using the post-2016 WHO classification. To do this, we conducted a PUBMED, SCOPUS, OVID SP, SciELO, and INFORMA search using the keywords; 'biomarker', 'diagnosis', 'atypical', 'meningioma', 'prognosis', 'grade I', 'grade 1', 'grade II' and 'grade 2'. Results We identified 1779 papers, 20 of which were eligible for systematic review according to the defined inclusion and exclusion criteria. From the review, we identified radiological characteristics (irregular tumour shape, tumour growth rate faster than 3cm3/year, high peri-tumoural blood flow), blood markers (low serum TIMP1/2, high serum HER2, high plasma Fibulin-2) and histological markers (low H3K27me3, low SMARCE1, low AKAP12, high ARIDB4) that may aid in differentiating grade II from grade I meningiomas. Conclusion Being able to predict meningioma grade at presentation using the radiological and blood markers described may influence management as the likely grade II tumours will be followed up or treated more aggressively, while the histological markers may prognosticate progression or post-treatment recurrence. This to an extent offers a more personalised treatment approach for patients.

Longitudinal studies among people with Multiple Sclerosis (pwMS) have shown that self-efficacy is linked to physical, cognitive and psychological functioning.To determine the distribution of self-efficacy in a large sample of pwMS, examining whether there are distinct groups which show different self-efficacy trajectories over time, and the health status characteristics of any groups identified.Participants completed serial questionnaire packs, including Unidimensional Self-efficacy-MS (USE-MS) scale, for the Trajectories of Outcome in Neurological Conditions-MS (TONiC-MS) study over an average 46-month period. The resulting longitudinal data were analysed by a group-based trajectory model.5887 pwMS were studied: mean age 50.2 years (SD 12.0); 73.6% female; Relapsing Remitting MS (61.8%), Secondary Progressive (22.9%), Primary Progressive (11.1%), Rapidly Evolving Relapsing Remitting MS (4.2%). Four distinct self-efficacy trajectories emerged, with declining, slightly declining, stable or improving self-efficacy, each showing different patterns of health status indicators such as EQ-5D-5L, disability and depression. USE-MS ≤ 18 at baseline detected all participants in the two declining groups.Future trials on interventions for self-efficacy should assume a priori that those with low levels of self-efficacy (USE-MS ≤ 18 at baseline) are likely to be on a declining trajectory and may need different interventions from those with stable self-efficacy.

Objectives: The World Health Organization Quality of Life-BREF Scale (WHOQOL-BREF) is a generic QOL measure with four domains covering Physical, Psychological, Social and Environment. Providing the opportunity to contrast QoL with other conditions, or with population norms, the current study had three aims: 1) can the established domains of the WHOQOL-BREF be validated within a large ALS/MND population; 2) can a total score be validated and 3) can they provide interval level measurement? Methods: Data were obtained from the Trajectories of Outcomes in Neurological Conditions study. Internal construct validity was determined by fit of the data to the Rasch measurement model. Results: 636 participants with ALS/MND were included. All domains, except the Social domain, showed satisfactory fit to the Rasch model. All were unidimensional, and showed no Differential Item Functioning by age, gender, or onset type. Finally, a total score was validated from a bi-factor perspective. Conclusions: The WHOQOL-BREF is valid for use in populations with ALS/MND and can be analyzed to yield interval level measurement: It offers a range of domains that reflect QOL, which can be used for parametric analysis and for comparison with other conditions or general populations, two advantages for its inclusion as a trial outcome measure and for observational studies.

Failure to clear oral secretions can be debilitating for patients with amyotrophic lateral sclerosis (ALS), but the treatment of this symptom is poorly defined and there is no consensus on best practice. The objective of this study was to identify the treatments that are commonly prescribed, and to describe how experienced clinicians manage a patient with treatment resistant symptoms. Twenty-three clinicians were approached, of which 19 from 16 centres across the UK provided case report forms for a total of 119 ALS patients identified as having problematic oral secretions. The use of five anticholinergics, salivary gland botulinum toxin injections, conservative management approaches and carbocisteine were reported. Of the 72 patients who were evaluated following the initiation of a first anticholinergic, 61% had symptomatic improvement. Only 19% of patients achieved symptomatic improvement with the use of an alternative anticholinergic when an initial anticholinergic achieved no symptomatic improvement. Problems with thick and thin secretions often coexisted, with 37% of patients receiving treatment for both types of problem. In conclusion, a variety of treatment options are employed by expert clinicians for problematic oral secretions in ALS patients. The variation in management highlights the need for further prospective research in this area.

Schwannomas, meningiomas and ependymomas are tumours of the nervous system which occur sporadically or as part of the hereditary disease neurofibromatosis type 2 (NF2). Mutations in neurofibromin 2/NF2 gene cause all NF2-related schwannomas, meningiomas and ependymomas, 77% sporadic schwannomas, 60% sporadic meningiomas and 30% sporadic ependymomas.1 Schwannomas are the hallmark of NF2 and develop in all patients with NF2. Current treatments for NF2-related tumours are surgery or radiosurgery. Radiation may induce additional mutations and formation of secondary tumours in NF2 whereas surgery has limited use in patients with high tumour load or tumours located at the sites where resection would cause neurological complications.2 Avastin is effective but only in a fraction of patients.2 Published consensus recommendations suggest that the development of effective therapies for NF2 is urgent, with great potential for clinical progress.2 Platelet-derived growth factor receptor β (PDGFRβ) is overexpressed and activated in human primary schwannoma cells leading to increased proliferation.3 Using orally available, Food and Drug Administration (FDA)-approved cRAF/VEGFR-2/PDGFRβ inhibitor, sorafenib, this was successfully inhibited in vitro.3 Here we report an open-label, phase 0, single-agent trial (EudraCT: 2011-001789-16, REC: 11/LO/0771) testing sorafenib in patients with NF2 with the aim to determine whether molecular target inhibition occurs with oral sorafenib in patients with NF2 and whether target inhibition in plasma with oral sorafenib in patients with NF2 can act as a biomarker. Per protocol minimal recruitment target depending on the pharmacodynamic (PD) response rate was three patients (two out of three or three out of five with 60% PD response).4 Here, five adult patients with NF2 with peripheral schwannomas (PS), diagnosed according to National Institute of Health (NIH) Diagnostic Criteria for NF, were treated with sorafenib administered orally at maximum tolerated dose (MTD) of 400 mg, two times a day, for 10 …

A minority of meningiomas are difficult to treat with surgery or radiotherapy, and chemotherapeutic alternatives are limited. This study aims to better understand pathways that are active in meningiomas, in order to direct future treatment strategies. We investigated the expression and activation of multiple growth factor receptors, their ligands and downstream signalling pathways in 30 meningiomas using immunohistochemistry. Expression was correlated with chromosome 22q loss. Membrane expression of VEGF receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR)β was seen in 83% of tumors, Axl in 70%, EGFR in 50% and insulin-like growth factor receptor in 47%. Expression was similar in low- and high-grade tumors, but membrane EGFR expression was not seen in tumors showing chromosome 22q loss (P

The 2011 annual meeting of the Children’s Tumor Foundation, the annual gathering of the neurofibromatosis (NF) research and clinical communities, was attended by 330 participants who discussed integration of new signaling pathways into NF research, the appreciation for NF mutations in sporadic cancers, and an expanding pre-clinical and clinical agenda. NF1, NF2, and schwannomatosis collectively affect approximately 100,000 persons in US, and result from mutations in different genes. Benign tumors of NF1 (neurofibroma and optic pathway glioma) and NF2 (schwannoma, ependymoma, and meningioma) and schwannomatosis (schwannoma) can cause significant morbidity, and there are no proven drug treatments for any form of NF. Each disorder is associated with additional manifestations causing morbidity. The research presentations described in this review covered basic science, preclinical testing, and results from clinical trials, and demonstrate the remarkable strides being taken toward understanding of and progress toward treatments for these disorders based on the close interaction among scientists and clinicians.

Deficiency of the tumor suppressor protein merlin leads to the development of benign tumors of the nervous system such as schwannomas, ependymomas and meningiomas. These tumors can occur spontaneously or as part of a tumor predisposition syndrome called neurofibromatosis type 2 (NF2), which involves multiple tumors. Schwannomas are the hallmark tumors of NF2 and are the most frequent and well-characterized of the merlin-deficient tumors. Surgery or radiotherapy are used to treat single tumors and can leave the patient with substantial morbidity. Limitations of other treatment options for merlin-deficient tumors, such as the lack of effectiveness of chemotherapy, have led to an urgent requirement for new pharmaceutical therapies. Merlin-deficient tumors are genetically well-defined, which allows rational testing of new molecular therapies that have been developed and successfully used to treat various cancers in the past few years. This Review centers on four key families of receptor tyrosine kinases-the ErbB family, platelet-derived growth factor receptor β, insulin-like growth factor 1 receptor, and vascular endothelial growth factor receptors-focusing on their role in schwannoma pathobiology and the therapeutic potential of targeting these receptors and their downstream signaling pathways.

Vestibular schwannomas (VS) arising sporadically or in patients with neurofibromatosis type 2 (NF2) consistently lack expression of Merlin, a tumor suppressor. Conventional treatment options include surgery and radiotherapy but there is no validated medical option. Recent evidence suggests that Merlin deficiency may result in abnormal activation of receptor tyrosine kinases (RTKs) and downstream signaling, promoting tumor growth. Although small-molecule RTK inhibitors are widely available for clinical use, no such therapy has been validated in patients with VS. To screen for RTK activation, surgical VS specimens from patients with and without NF2 were analyzed by phospho-RTK profiling arrays. Downstream signaling pathway activation was analyzed by phospho-MAPK arrays. Activated RTKs and downstream kinases were validated immunohistochemically in corresponding formalin-fixed, paraffin-embedded tissues. Phospho-RTK arrays and immunohistochemistry showed consistent overexpression and activation of EGFR family receptors and evidence of ERK1/2 downstream signaling was observed in all samples analyzed (n = 11). Based on the findings, the small-molecule EGFR/ErbB2 kinase inhibitor lapatinib was selected for evaluation of target inhibition and treatment efficacy in our in vitro human schwannoma model. EGFR/ErbB2 targeted therapy with lapatinib inhibited ErbB2 phosphorylation and survivin upregulation, as well as downstream ERK1/2 and AKT activation, resulting in decreased proliferation. We conclude that EGFR family receptor activation is a consistent feature of both sporadic and NF2-related VS. Molecular targeted therapy with lapatinib downregulates survivin and has antiproliferative activity in a preclinical VS model. Based on these findings, a clinical trial with lapatinib for the treatment of VS is currently underway.

The epidemiology of motor neurone disease (MND) in the counties of Devon and Cornwall in the southwest of England has not previously been studied. A previous study of England and Wales has, however, reported a very high death certification rate of MND in Devon. This study was carried out to establish the prevalence and incidence of MND in Devon and Cornwall and make comparisons with published rates in other populations. We attempted to identify all cases of MND diagnosed in Devon and Cornwall between 2002 and 2007. Case identification was centred on the major hospitals in the two counties and multiple sources of ascertainment were used. All identified cases had their case notes reviewed to establish the diagnosis and classify by type of MND. Point prevalence of MND was established for September 1st, 2007. The overall incidence rate standardised to the 2001 United Kingdom population was 2.52 per 100,000 (95% confidence interval 2.20-2.84). The incidence rate was significantly higher in males (P < 0.001). The estimated male to female incidence ratio was 2.10 (95% CI 1.61-2.73). The crude incidence rate in Cornwall was 3.78 per 100,000 (95% CI 3.03-4.53) and this was significantly higher (P = 0.011) than the rate in Devon, which was 2.61 per 100,000 (95% CI 2.19-3.04). The standardised incidence rate for the study period in Devon was 2.26 per 100,000 (95% CI 1.91-2.60) and in Cornwall it was 3.06 per 100,000 (95% CI 2.44-3.68). The overall standardised point prevalence rate was 5.66 per 100,000 (95% CI 4.49-6.83). The incidence rate of MND in our study is similar to reported findings in large prospective studies of the disease. There is a significant difference between the incidence rates in Devon and Cornwall. There is a need to establish a prospective MND Register to accurately document the epidemiological characteristics of the disease in the two counties.

Objective: Clinically validated biomarkers for neurofibromatosis 1 (NF1), neurofibromatosis 2 (NF2), and schwannomatosis (SWN) have not been identified to date. The biomarker working group9s goals are to (1) define biomarker needs in NF1, NF2, and SWN; (2) summarize existing data on biomarkers in NF1, NF2, and SWN; (3) outline recommendations for sample collection and biomarker development; and (4) standardize sample collection and methodology protocols where possible to promote comparison between studies by publishing standard operating procedures (SOPs). Methods: The biomarker group reviewed published data on biomarkers in NF1, NF2, and SWN and on biobanking efforts outside these diseases via literature search, defined the need for biomarkers in NF, and developed recommendations in a series of consensus meetings. Results: We describe existing biomarkers in NF and report consensus recommendations for SOP and a minimal clinical dataset to accompany samples derived from patients with NF1, NF2, and SWN in decentralized biobanks. Conclusions: These recommendations are intended to provide clinicians and researchers with a common set of guidelines to collect and store biospecimens and for establishment of biobanks for NF1, NF2, and SWN.

INTRODUCTION: A significant minority of meningiomas are difficult to treat with surgery or radiotherapy, and there are limited chemotherapeutic alternatives. This study aims to better understand the pathways that are active in these tumours, in order to direct future treatment strategies. METHOD: We have investigated the expression of several growth factors and their signalling pathways in 30 meningiomas, using immunohistochemistry and Western blots. Expression was correlated with presumed NF2 gene status, using fluorescent in situ hybridisation to look for chromosome 22q loss. RESULTS: Membrane expression of VEGFR and PDGFR-beta was seen in 83% of tumours, Axl in 70%, EGFR in 50% and IGFR in 47%. Expression was similar in low and high grade tumours, but membrane EGFR expression was not seen in tumours showing chromosome 22q loss. Expression of the ligands IGF, NRG, VEGF, Gas 6, and downstream signalling proteins, Mek, Erk, Jnk and Akt, and pS6RP, was widespread. Our findings suggest that the majority of meningiomas express and show activation of multiple growth factor receptors and their downstream signalling pathways irrespective of tumour grade. CONCLUSION: In addition to previously reported receptors, Axl may also offer an attractive therapeutic target. Our findings also suggest that anti-EGFR based therapies may be less effective in meningiomas with 22q loss.

This MRI study was performed to evaluate in vivo alterations of the spinal cord in defined subgroups of motor neuron diseases. Standard MRI examinations of the cervical and thoracic spinal cord in sporadic amyotrophic lateral sclerosis (ALS; n = 39), sporadic lower motor neuron disease (LMND; n = 19), Kennedy’s disease (KD; n = 19) and a control group (n = 96) were analyzed with respect to spinal cord signal changes and the thickness of the spinal cord. No significant changes in thickness or signal alterations were observed when comparing ALS, LMND and control groups with one another. However, in KD patients significant upper spinal cord atrophy was detected at the cervical level as compared with all other groups. At the thoracic level, KD patients had significant upper cord atrophy as compared with controls and LMND. Marked atrophy of the upper spinal cord seems to be a feature of the KD-associated central-peripheral distal axonopathy.

Purpose of the review Secondary axonal atrophy is common in most if not all demyelinating neuropathies and is likely responsible for the majority of clinical symptoms. We review clinical, electrophysiological and morphological evidence for secondary axonal atrophy in demyelinating neuropathies and summarize recent hypotheses on possible pathomechanisms. Recent findings Elucidation of genetic defects responsible for hereditary demyelinating neuropathies and insights into axon-Schwann cell interactions have allowed longitudinal studies of genetically defined demyelinating neuropathies and research into the pathomechanism of secondary axonal atrophy. Summary There is ample clinical electrophysiological and electropathological evidence that secondary axonal atrophy is found in hereditary and demyelinating neuropathies. Recognizing secondary axonal atrophy as a main cause for clinical disability in demyelinating neuropathies is important for the clinician and may reveal a therapeutic target common to all different forms of demyelinating neuropathies.

Focal peri-ictal abnormalities on cerebral imaging are well described [1], most commonly mimicking tumours [2, 5]. More extensive abnormalities resembling cerebral ischaemia are more rarely described. Here we describe a case of extensive peri-ictal cerebral oedema. A 37 year-old man with a known craniopharyngioma and secondary epilepsy presented following a cluster of tonic-clonic seizures occurring over the course of a day. At the time of admission he was experiencing generalised tonic-clonic seizures every 10 min. He was apyrexial and normotensive. Neurological examination showed rightsided hemiparesis, right hemianopia and dysphasia. His white blood cell count and C reactive protein were normal. Treatment with phenytoin and lorazepam resulted in resolution of his seizures. He had been diagnosed with craniopharyngioma at the age of 20 when he presented with a 4-year history of partial seizures manifesting as vacant episodes or right arm focal motor jerks. MRI scan at the time revealed the tumour to be compressing the left temporal and frontal lobes, and engulfing but not compromising the left middle cerebral artery (MCA). It was thought that the tumour was not resectable and his epilepsy was treated with sodium valproate and topiramate. He continued to experience monthly tonic-clonic seizures with partial seizures occurring at least weekly. On admission following his seizure cluster, CT scan of the head showed low attenuation of grey and white matter in the left hemisphere with the craniopharyngioma unchanged from previous scans (Fig. 1a–c). The appearances were suggestive of oedema and there was concern that it might have been of ischaemic etiology caused by tumour invasion into the left MCA. However, CT angiogram of the intracranial vessels demonstrated patent arteries in both hemispheres. An MRI scan on day 4 demonstrated oedema in the posterior frontal, parietal and occipital lobes, mainly affecting the cortical grey matter (Fig. 1d,e). Diffusion weighted imaging (DWI) revealed increased signal intensity in the same distribution; there was no evidence of acute restricted diffusion abnormality (Fig. 1f). The patient’s neurological deficit gradually resolved over the following 2 weeks. An MRI scan performed 5 months later showed complete resolution of oedema (Fig. 2), and his seizure frequency improved such that he only experienced very occasional complex partial seizures. Brain oedema is well described following prolonged epileptic seizures, including partial status [6, 8, 9], nonconvulsive status [3] and convulsive status [1, 7, 8]. The focal changes on imaging can imitate a tumour [5, 9] or ischaemic lesion [9]. Indeed, the focality of the changes has been suggested to be a useful marker for seizure focus [7]. Our case is unusual in having extensive oedematous involvement of one hemisphere. The changes evident on imaging are thought to be due to a combination of vasogenic and cytotoxic oedema due C. Carroll (&) C. O. Hanemann Department of Clinical Neurobiology, Peninsula Medical School, The John Bull Building, Tamar Science Park, Plymouth PL6 8BU, UK e-mail: camille.carroll@pms.ac.uk

Advances in molecular biology have resulted in novel therapy for neurofibromatosis 2-related (NF2) tumours, highlighting the need for robust outcome measures. The disease-focused NF2 impact on quality of life (NFTI-QOL) patient questionnaire was assessed as an outcome measure for treatment in a multi-centre study. NFTI-QOL was related to clinician-rated severity (ClinSev) and genetic severity (GenSev) over repeated visits. Data were evaluated for 288 NF2 patients (n = 464 visits) attending the English national NF2 clinics from 2010 to 2012. The male-to-female ratio was equal and the mean age was 42.2 (SD 17.8) years. The analysis included NFTI-QOL eight-item score, ClinSev graded as mild, moderate, or severe, and GenSev as a rank order of the number of NF2 mutations (graded as mild, moderate, severe). The mean (SD) 8.7 (5.4) score for NFTI-QOL for either a first visit or all visits 9.2 (5.4) was similar to the published norm of 9.4 (5.5), with no significant relationships with age or gender. NFTI-QOL internal reliability was good, with a Cronbach’s alpha score of 0.85 and test re-test reliability r = 0.84. NFTI related to ClinSev (r = 0.41, p < 0.001; r = 0.46 for all visits), but weakly to GenSev (r = 0.16, p < 0.05; r = 0.15 for all visits). ClinSev related to GenSev (r = 0.41, p < 0.001; r = 0.42 for all visits). NFTI-QOL showed a good reliability and ability to detect significant longitudinal changes in the QOL of individuals. The moderate relationships of NFTI-QOL with clinician- and genetic-rated severity suggest that NFTI-QOL taps into NF2 patient experiences that are not encompassed by ClinSev rating or genotype.

The neurofibromatoses (NF)--including neurofibromatosis 1 (NF1), neurofibromatosis 2 (NF2), and schwannomatosis--are related tumor-suppressor syndromes characterized by a predisposition to multiple tumor types and other disease manifestations, which often result in functional disability, reduced quality of life, pain, and, in some cases, malignancy. With increasing knowledge of the biology and pathogenesis of NF, clinical trials with targeted agents directed at NF tumors have become available. Most clinical trials for patients with NF have used designs and endpoints similar to oncology trials. However, differences in the disease manifestations and natural history of NF (compared to cancers) require the development of new designs and endpoints to perform meaningful NF clinical trials. The Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration was established in 2011 at the Children's Tumor Foundation meeting to achieve consensus within the NF community about the design of future clinical trials, with a specific emphasis on endpoints. The REiNS Collaboration includes 7 working groups that focus on imaging of tumor response; functional, visual, patient-reported, and neurocognitive outcomes; whole-body MRI; and disease biomarkers. This supplement includes the first series of recommendations by the REiNS Collaboration. The hope is that these recommendations will be used by members of the group and by researchers outside of the REiNS International Collaboration to standardize the measurement of outcomes and thus improve clinical trials for patients with NF. Ultimately, we plan to engage industry partners and national regulatory agencies in this process to facilitate the approval of drugs for patients with NF.

Loss of the Merlin tumour suppressor causes abnormal de-differentiation and proliferation of Schwann cells and formation of schwannoma tumours in patients with neurofibromatosis type 2. Within the mature peripheral nerve the normal development, differentiation and maintenance of myelinating and non-myelinating Schwann cells is regulated by a network of transcription factors that include SOX10, OCT6 (now known as POU3F1), NFATC4 and KROX20 (also known as Egr2). We have examined for the first time how their regulation of Schwann cell development is disrupted in primary human schwannoma cells. We find that induction of both KROX20 and OCT6 is impaired, whereas enforced expression of KROX20 drives both myelin gene expression and cell cycle arrest in Merlin-null cells. Importantly, we show that human schwannoma cells have reduced expression of SOX10 protein and messenger RNA. Analysis of mouse SOX10-null Schwann cells shows they display many of the characteristics of human schwannoma cells, including increased expression of platelet derived growth factor receptor beta (PDGFRB) messenger RNA and protein, enhanced proliferation, increased focal adhesions and schwannoma-like morphology. Correspondingly, reintroduction of SOX10 into human Merlin-null cells restores the ability of these cells to induce KROX20 and myelin protein zero (MPZ), localizes NFATC4 to the nucleus, reduces cell proliferation and suppresses PDGFRB expression. Thus, we propose that loss of the SOX10 protein, which is vital for normal Schwann cell development, is also key to the pathology of Merlin-null schwannoma tumours.

Cannabinoids have been shown to have a beneficial effect in both animal models of multiple sclerosis (MS) and human disease, although the mechanisms of action are unclear. We examined expression of the major cannabinoid receptors [(CBRs) cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2)] and a key enzyme involved in synthesis of the endocannabinoid anandamide [N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD)] in autopsy brain samples from patients with MS. CB1 was expressed in neurons, injured axons, oligodendrocytes, macrophages/microglia, some astrocytes, endothelial cells, smooth muscle cells and pericytes. CB2 and NAPE-PLD were localized to cerebral endothelial cells, pericytes, smooth muscle cells, astrocytes and macrophages/microglia. NAPE-PLD immunoreactivity was also seen in neurons. Endothelial CB2 expression was greatest in chronic inactive plaques, and in areas was seen in segments of endothelium where the endothelial expression of adhesion molecules (VCAM-1 and ICAM-1) was focally undetectable, and was often expressed in areas of blood-brain barrier damage. Vascular density was increased in chronic active plaques and normal-appearing white matter compared with controls. These data support findings from animal models which suggest a role for the endocannabinoid system in the MS, particularly in the regulation of endothelial leukocyte adhesion and the cellular response to injury.

Schwannomas are Schwann cell tumors of the nervous system that occur spontaneously and in patients with neurofibromatosis 2 (NF2) and lack the tumor suppressor merlin. Merlin is known to bind paxillin, beta1 integrin and focal adhesion kinase, members of focal contacts, multi-protein complexes that mediate cell adhesion to the extracellular matrix. Moreover, merlin-deficient Schwannomas show pathological adhesion to the extracellular matrix making the characterization of focal contacts indispensable. Using our Schwannoma in vitro model of human primary Schwann and Schwannoma cells, we here show that Schwannoma cells display an increased number of mature and stable focal contacts. In addition to an involvement of RhoA signaling via the Rho kinase ROCK, Rac1 plays a significant role in the pathological adhesion of Schwannoma cells. The Rac1 guanine exchange factor- beta-Pix, localizes to focal contacts in human primary Schwannoma cells, and we show that part of the Rac1 activation, an effect of merlin-deficiency, occurs at the level of focal contacts in human primary Schwannoma cells. Our results help explaining the pathological adhesion of Schwannoma cells, further strengthen the importance of RhoGTPase signaling in Schwannoma development, and suggest that merlin's role in tumor suppression is linked to focal contacts.

Mutations in the tumor suppressor gene coding for merlin cause Neurofibromatosis type 2 (NF2), all spontaneous schwannomas, and a majority of meningiomas. Merlin links transmembrane proteins to the cytoskeleton. Accordingly, primary human schwannoma cells lacking merlin show an increased number of lamellipodia and filopodia as well as increased cell spreading. We show enhanced adhesion in primary human schwannoma cells and present evidence that this is dependent on the integrin chains alpha6beta1 and alpha6beta4. We further demonstrate that the integrin chains beta1 and beta4 are upregulated in schwannomas using different complementary methods, and report higher expression of these integrins per schwannoma cell by fluorescence assisted cell sorting (FACS). Finally we report clustering of the integrin chains alpha6, beta1, and beta4 on schwannoma cells. Our findings fit well into recent data on the role of merlin in signaling cascades connected to integrins and help explain pathological ensheathment of extracellular matrix or pseudomesaxon formation which is a hallmark of schwannoma histopathology.

The authors reviewed the occurrence and concomitant factors of laryngospasm in X-linked spinobulbar muscular atrophy (Kennedy disease [KD]). Recurrent laryngospasm was observed in 47% of 49 patients with KD, but in only 2% of a control group of patients with early-stage ALS.

Background X-linked hereditary demyelianting neuropathies (Charcot-Marie-Tooth Disease [CMTX]) caused by mutations in the connexin 32 (Cx32) gene account for approximately 10% to 20% of all hereditary demyelinating neuropathies. Mild subclinical central nervous system (CNS) involvement has been previously described, and CMTX patients with transient white matter lesions allied to CNS symptoms have very recently been described. This is of potential interest, as Cx32 is widely expressed in both peripheral nerve and the brain. Patients We describe a family with hereditary demyelinating neuropathy and transient CNS symptoms. For this study, family members underwent genotyping and detailed clinical, electrophysiological, and magnetic resonance imaging examination. Results We present a CMTX family with a novel mutation in the Cx32 gene. Affected family members show, in addition to the classic polyneuropathy, transient and reversible white matter lesions on magnetic resonance imaging scans, correlating similarly transient CNS symptoms. Conclusion Patients with CMTX can present with transient CNS symptoms and marked white matter lesions on magnetic resonance imaging scans.

The hereditary demyelinating neuropathy Charcot-Marie-Tooth type 1A is caused by duplication or by point mutations of the PMP22 gene. Histopathological differences in these genotypes suggest distinct disease mechanisms. In the present investigation we demonstrate a pathologically altered cellular distribution of PMP22 in sural nerve biopsies of patients with PMP22 point mutations. In these patients, in contrast to findings in patients with PMP22 duplication, PMP22 partially accumulates in the Schwann cells instead of being inserted in the myelin sheath. These findings may explain the different histopathology and may suggest different mechanisms of pathogenesis in these genotypes.

Introduction Cannabinoids such as Δ9–tetrahydrocannabinol (Δ9–THC) are neuroprotective in animal and cell culture models of Parkinson9s disease (PD). In a PD cell culture model we recently demonstrated that Δ9–THC is neuroprotective through activation of the nuclear receptor peroxisomal proliferator–activated receptor γ (PPARγ). Furthermore, activation by specific agonists rosiglitazone and pioglitazone, has also been found neuroprotective. PPARγ is a nuclear receptor whose activation can lead to the expression of proteins involved in the de novo synthesis of mitochondria. One such protein is the PPARγ co–activator 1 α (PGC1α) as it co–activates NRF–1 mediated gene expression which is essential for the production of nuclear encoded, mitochondrial proteins. Here we investigate the effect of Δ9–THC and pioglitazone on mitochondrial biogenesis. Methods SH–SY5Y neuroblastoma cells were differentiated with retinoic acid and exposed to the PD relevant mitochondrial complex 1 inhibitor, MPP+. Δ9–THC and pioglitazone were co–administered with the minimum concentration of the specific PPARγ antagonist T0070907 able to block the protective effect of each compound respectively for 48 hours. The production of reactive oxygen species was then measured, proteins were extracted for Western blotting and total DNA was extracted to determine mitochondrial DNA (mtDNA) content by QPCR. Results Δ9–THC resulted in significant inhibition of MPP+ induced oxidative stress which was completely reversed by T0070907 whereas pioglitazone induced reduction in oxidative stress did not seem to be PPARγ dependent. Accordingly, both pioglitazone and Δ9–THC were able to restore MPP+ induced down–regulation of PGC1α, to the level of untreated control. This effect was inhibited by T0070907 in the case of Δ9–THC but not pioglitazone. Whilst NRF1 expression remained unaffected by all treatments, the mitochondrial transcription factor (tfam) which is necessary for mtDNA replication was reduced with MPP+ and up–regulated by Δ9–THC only. Similarly, mtDNA content and the mitochondrial marker COX4 were only increased by Δ9–THC. Conclusions Even though Δ9–THC and pioglitazone are both protective against MPP+ only Δ9–THC induces PPARγ dependent mitochondrial biogenesis, a mechanism that may be beneficial for the treatment of PD.

Objective To characterize the earliest symptoms of X-linked bulbospinal neuronopathy (Kennedy disease [KD]) during the course of the disease, including a definition of the age of onset. Methods We describe the earliest symptoms, signs on clinical investigation, electrophysiological and muscle biopsy specimen findings, and creatine kinase levels in 34 patients with KD. Correlations were made among the CAG-repeat length and clinical symptoms, age at onset, and the presence of electrophysiological and laboratory findings. Results Our findings indicate that the age at onset of KD is in adolescence which is earlier than previously thought. Most frequently early symptoms are gynecomastia, muscle pain, and premature muscular exhaustion. Weakness is not a typical initial symptom and is frequently found in distal limbs if present early. We found a correlation between the of number of CAG repeats and the age at onset of weakness but not to the age at onset of KD. Furthermore, no correlations were found between the occurrence of gynecomastia, tremor, increased creatine kinase levels, and additional myopathic changes in muscle biopsy specimens. Conclusions Our data show that KD is a multisystem disorder with onset in adolescence. Because of the heterogeneity of clinical presentation and no correlation between the number of CAG repeats and most of the clinical hallmarks of KD, we suggest that other environmental or genetic factors contribute to the manifestation of specific organ systems in KD.

Schwannomas, tumors originating from Schwann cells, represent a frequent neurological tumor and can occur both in a genetic disorder called neurofibromatosis type 2 (NF2) and sporadically. In both cases the genetic background is identical as all schwannomas are caused by biallelic mutations in the tumor suppressor gene NF2 coding for merlin. Mutations in this gene have also been found to be responsible for 50% to 60% of spontaneous and 100% of the NF2 associated meningiomas. The NF2 gene product, merlin, links transmembrane proteins to the cytoskeleton and is involved in intracellular signaling processes. It has previously been shown that reexpression of wild-type merlin in primary human schwannoma cells leads to an increase in the number of apoptotic cells. Here, we report in vivo and in vitro evidence that the basal apoptosis rate of primary human schwannoma cells is reduced in comparison to that of normal Schwann cells, supporting the idea that in this benign tumor type, apoptosis has a role in tumorigenesis.