Heterozygous CAPN3 missense variants causing autosomal-dominant calpainopathy in seven unrelated families

[Aims] Recessive variants in CAPN3 gene are the cause of the commonest form of autosomal recessive limb girdle muscle dystrophy. However, two distinct in-frame deletions in CAPN3 (NM_000070.3:c.643_663del21 and c.598_621del15) and more recently, Gly445Arg and Arg572Pro substitutions have been linked to autosomal dominant (AD) forms of calpainopathy. We report 21 affected individuals from seven unrelated families presenting with an autosomal dominant form of muscular dystrophy associated with five different heterozygous missense variants in CAPN.[Methods] We have used massively parallel gene sequencing (MPS) to determine the genetic basis of a dominant form of limb girdle muscular dystrophy in affected individuals from seven unrelated families.[Results] The c.700G> A, [p.(Gly234Arg)], c.1327T> C [p.(Ser443Pro], c.1333G> A [p.(Gly445Arg)], c.1661A> C [p.(Tyr554Ser)] and c.1706T> C [p.(Phe569Ser)] CAPN3 variants were identified. Affected individuals presented in young adulthood with progressive proximal and axial weakness, waddling walking and scapular winging or with isolated hyperCKaemia. Muscle imaging showed fatty replacement of paraspinal muscles, variable degrees of involvement of the gluteal muscles, and the posterior compartment of the thigh and minor changes at the mid-leg level. Muscle biopsies revealed mild myopathic changes. Western blot analysis revealed a clear reduction in calpain 3 in skeletal muscle relative to controls. Protein modelling of these variants on the predicted structure of calpain 3 revealed that all variants are located in proximity to the calmodulin-binding site and are predicted to interfere with proteolytic activation.[Conclusions] We expand the genotypic spectrum of CAPN3-associated muscular dystrophy due to autosomal dominant missense variants.This study was funded in part by Instituto de Salud Carlos III through the project PI14/00738 to M. O. (co-funded by European Regional Development Fund. ERDF, a way to build Europe). We thank CERCA Programme / Generalitat de Catalunya for institutional support NGL (APP1117510) and GR (APP1122952) are supported by the Australian National Health and Medical Research Council (NHMRC). This work is also funded by an NHMRC Project Grant (APP1080587).Peer reviewe

Combined in-silico and on-chip validation of pseudopalisade formation hypothesis in Glioblastoma

Introduction: Hypercellular regions surrounding necrotic areas in glioblastoma (GBM), named pseudopalisades, are characteristic of these tumors and have been hypothesized to be waves of migrating GBM cells. These structures are thought to be induced by oxygen depletion caused by the accumulation of cells far from nutrient supplies (chronic hypoxia) and/or tumor-induced blood vessel occlusion (acute hypoxia). The universal appearance of these structures in GBM suggests that they may play an instrumental role in their spreading and invasion. However the validation of the mechanisms of pseudopalisade formation has remained challenging. Materials and methods: A mathematical model was developed incorporating the main mechanisms of pseudopalisade formation. Oxygen coming from straight vessels drives phenotype changes. A third phenotype was included accounting for hypoxic cells switching back to a more proliferative phenotype in regions of normoxia. Experiments were done by embedding different densities of U-251 MG cells within a collagen hydrogel in a custom-designed microfluidic device. By controlling the medium flow through lateral microchannels, we mimic and control blood-vessel obstruction events associated with this disease. Results: Nutrient and oxygen starvation triggered a strong migratory process leading to pseudopalisade generation in silico and in vitro. Also, cells at greatest distance from oxygen supply became hypoxic after a critical point in tumor growth was reached (due to increased metabolism) forming pseudopalisades both in silico and in vitro. All the elements included in the mathematical model were necessary to describe both types of phenomena pointing out to the insufficiency of the go-or-grow hypothesis to describe pseudopalisade formation on-chip. Conclusions: Using a combination of computational and experimental techniques, we proved the feasibility of the two hypotheses of pseudopalisade formation, driven by either acute or chronic hypoxia. Additionally, we verified the potential of microfluidic devices as advanced artificial systems capable of experimentally modeling nutrient and oxygen gradients during tumor evolution

Correction to: SEOM clinical guideline of diagnosis and management of low-grade glioma (2017).

The original version of this article unfortunately contained a mistake. Figure 3 was incorrect

SEOM clinical guideline of diagnosis and management of low-grade glioma (2017).

Diffuse infiltrating low-grade gliomas include oligodendrogliomas and astrocytomas, and account for about 5% of all primary brain tumors. Treatment strategies for these low-grade gliomas in adults have recently changed. The 2016 World Health Organization (WHO) classification has updated the definition of these tumors to include their molecular characterization, including the presence of isocitrate dehydrogenase (IDH) mutation and 1p/19p codeletion. In this new classification, the histologic subtype of grade II-mixed oligoastrocytoma has also been eliminated. The precise optimal management of patients with low-grade glioma after resection remains to be determined. The risk-benefit ratio of adjuvant treatment must be weighed for each individual

STAT3 labels a subpopulation of reactive astrocytes required for brain metastasis.

The brain microenvironment imposes a particularly intense selective pressure on metastasis-initiating cells, but successful metastases bypass this control through mechanisms that are poorly understood. Reactive astrocytes are key components of this microenvironment that confine brain metastasis without infiltrating the lesion. Here, we describe that brain metastatic cells induce and maintain the co-option of a pro-metastatic program driven by signal transducer and activator of transcription 3 (STAT3) in a subpopulation of reactive astrocytes surrounding metastatic lesions. These reactive astrocytes benefit metastatic cells by their modulatory effect on the innate and acquired immune system. In patients, active STAT3 in reactive astrocytes correlates with reduced survival from diagnosis of intracranial metastases. Blocking STAT3 signaling in reactive astrocytes reduces experimental brain metastasis from different primary tumor sources, even at advanced stages of colonization. We also show that a safe and orally bioavailable treatment that inhibits STAT3 exhibits significant antitumor effects in patients with advanced systemic disease that included brain metastasis. Responses to this therapy were notable in the central nervous system, where several complete responses were achieved. Given that brain metastasis causes substantial morbidity and mortality, our results identify a novel treatment for increasing survival in patients with secondary brain tumors.We want to thank the CNIO Core Facilities for their excellent assistance. We also thank F.X. Real, O. Marin, M. Serrano, O. Fernandez-Capetillo and M. Soengas for critically reading the manuscript, P. Bos for advice with CD8+ T cell experiments, J. Massague (MSKCC) for the BrM cell lines, MEDA for Legasil, M. A. Perez (University of Copenhagen), H. Peinado (CNIO), M. Soengas (CNIO) and M. Squatrito (CNIO) for reagents. This work was supported by MINECO grants MINECO-Retos SAF201457243-R (M.V.), MINECO-Europa Excelencia SAF2015-62547-ERC (M.V.), FERO Grant for Research in Oncology (M.V.), Melanoma Research Alliance Young Investigator Award (M.V.), AECC Coordinated Translational Groups (M.V., E.M.-S. and S.R.y.C), SEOM (J.B.-B.), Pfizer WI190764 (J.B.-B.), Meda Pharma (J.B.-B.), Armangue Family Fund (JA.M. and J.B.-B.), La Caixa-Severo Ochoa International PhD Program Fellowship (L.Z.), FCT PhD Fellowship SFRH/BD/100089/2014 (C.M.), the Fulbright Program (W.B.). M.V. is a Ramon y Cajal Investigator (RYC-2013-13365). This work is dedicated to the memory of Maria Jesus Cortes Garin.S

Exercise intervention in a family with exercise intolerance and a novel mutation in the mitochondrial POLG gene

Mutations in the POLG gene, encoding the mitochondrial DNA (mtDNA) polymerase subunit gamma-1, have been identified in severe mtDNA depletion syndromes and mtDNA deletion disorders which include ataxia neuropathy spectrum disorders and AR and AD forms of progressive external ophthalmoplegia (PEO) and PEO-plus disorders. We report on a family with exercise intolerance. The proband was a 50-year-old man with severe muscle pain and premature fatigue after exercise of mild to moderate intensity. Serum CK ranged from 400 to 4500 U/L.Sin financiación2.969 JCR (2016) Q2, 72/194 Clinical Neurology, 124/259 Neurosciences1.421 SJR (2016) Q1, 69/380 Neurology (clinical), 32/313 Pediatrics, Perinatology and Child Health; Q2, 39/103 Genetics (clinical), 44/166 NeurologyNo data IDR 2016UE

Clinical, Histological, and Genetic Features of 25 Patients with Autosomal Dominant Progressive External Ophthalmoplegia (ad-PEO)/PEO-Plus Due to TWNK Mutations

Autosomal dominant mutations in the TWNK gene, which encodes a mitochondrial DNA helicase, cause adult-onset progressive external ophthalmoplegia (PEO) and PEO-plus presentations. In this retrospective observational study, we describe clinical and complementary data from 25 PEO patients with mutations in TWNK recruited from the Hospital 12 de Octubre Mitochondrial Disorders Laboratory Database. The mean ages of onset and diagnosis were 43 and 63 years, respectively. Family history was positive in 22 patients. Ptosis and PEO (92% and 80%) were the most common findings. Weakness was present in 48%, affecting proximal limbs, neck, and bulbar muscles. Exercise intolerance was present in 28%. Less frequent manifestations were cardiac (24%) and respiratory (4%) involvement, neuropathy (8%), ataxia (4%), and parkinsonism (4%). Only 28% had mild hyperCKemia. All 19 available muscle biopsies showed signs of mitochondrial dysfunction. Ten different TWNK mutations were identified, with c.1361T>G (p.Val454Gly) and c.1070G>C (p.Arg357Pro) being the most common. Before definitive genetic confirmation, 56% of patients were misdiagnosed (36% with myasthenia, 20% with oculopharyngeal muscle dystrophy). Accurate differential diagnosis and early confirmation with appropriately chosen complementary studies allow genetic counseling and the avoidance of unnecessary treatments. Thus, mitochondrial myopathies must be considered in PEO/PEO-plus presentations, and particularly, TWNK is an important cause when positive family history is present

Late-onset thymidine kinase 2 deficiency: a review of 18 cases

Abstract Background TK2 gene encodes for mitochondrial thymidine kinase, which phosphorylates the pyrimidine nucleosides thymidine and deoxycytidine. Recessive mutations in the TK2 gene are responsible for the ‘myopathic form’ of the mitochondrial depletion/multiple deletions syndrome, with a wide spectrum of severity. Methods We describe 18 patients with mitochondrial myopathy due to mutations in the TK2 gene with absence of clinical symptoms until the age of 12. Results The mean age of onset was 31 years. The first symptom was muscle limb weakness in 10/18, eyelid ptosis in 6/18, and respiratory insufficiency in 2/18. All patients developed variable muscle weakness during the evolution of the disease. Half of patients presented difficulty in swallowing. All patients showed evidence of respiratory muscle weakness, with need for non-invasive Mechanical Ventilation in 12/18. Four patients had deceased, all of them due to respiratory insufficiency. We identified common radiological features in muscle magnetic resonance, where the most severely affected muscles were the gluteus maximus, semitendinosus and sartorius. On muscle biopsies typical signs of mitochondrial dysfunction were associated with dystrophic changes. All mutations identified were previously reported, being the most frequent the in-frame deletion p.Lys202del. All cases showed multiple mtDNA deletions but mtDNA depletion was present only in two patients. Conclusions The late-onset is the less frequent form of presentation of the TK2 deficiency and its natural history is not well known. Patients with late onset TK2 deficiency have a consistent and recognizable clinical phenotype and a poor prognosis, due to the high risk of early and progressive respiratory insufficiency