Markus Weber

Repeat expansion in C9orf72 causes amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Expanded sense and antisense repeat RNA transcripts in C9orf72 are translated into five dipeptide-repeat proteins (DPRs) in an AUG-independent manner. We previously identified the heterogeneous ribonucleoprotein (hnRNP) A3 as an interactor of the sense repeat RNA that reduces its translation into DPRs. Furthermore, we found that hnRNPA3 is depleted from the nucleus and partially mislocalized to cytoplasmic poly-GA inclusions in C9orf72 patients, suggesting that poly-GA sequesters hnRNPA3 within the cytoplasm. We now demonstrate that hnRNPA3 also binds to the antisense repeat RNA. Both DPR production and deposition from sense and antisense RNA repeats are increased upon hnRNPA3 reduction. All DPRs induced DNA double strand breaks (DSB), which was further enhanced upon reduction of hnRNPA3. Poly-glycine–arginine and poly-proline-arginine increased foci formed by phosphorylated Ataxia Telangiectasia Mutated (pATM), a major sensor of DSBs, whereas poly-glycine–alanine (poly-GA) evoked a reduction of pATM foci. In dentate gyri of C9orf72 patients, lower nuclear hnRNPA3 levels were associated with increased DNA damage. Moreover, enhanced poly-GA deposition correlated with reduced pATM foci. Since cytoplasmic pATM deposits partially colocalized with poly-GA deposits, these results suggest that poly-GA, the most frequent DPR observed in C9orf72 patients, differentially causes DNA damage and that poly-GA selectively sequesters pATM in the cytoplasm inhibiting its recruitment to sites of DNA damage. Thus, mislocalization of nuclear hnRNPA3 caused by poly-GA leads to increased poly-GA production, which partially depletes pATM, and consequently enhances DSB.

Non-invasive ventilation (NIV) and percutaneous gastrostomy (PEG) are guideline-recommended interventions for symptom management in amyotrophic lateral sclerosis (ALS). Their effect on survival is controversial and the impact on causes of death is unknown. To investigate the effect of NIV and PEG on survival and causes of death in ALS patients. Eighty deceased ALS patients underwent a complete post mortem analysis for causes of death between 2003 and 2015. Forty-two of these patients consented for genetic testing. Effects of NIV and PEG on survival and causes of death were analyzed in a multivariable Cox proportional hazard regression. Six patients, who requested assisted suicide causing drug-induced hypoxia, were excluded from final analysis. Respiratory failure was the main cause of death in 72 out of 74 patients. Fifteen out of 74 died of aspiration pneumonia 23/74 of bronchopneumonia and 8/74 of a combination of aspiration pneumonia and bronchopneumonia. Twenty died of hypoxia without concomitant infection, and six patients had pulmonary embolism alone or in combination with pneumonia. NIV (p = 0.01) and PEG (pC9orf72 hexanucleotide repeat expansions showed faster disease progression and shorter survival (p = 0.01). The use of NIV and PEG prolongs survival in ALS. This study supports current AAN and EFNS guidelines which recommend NIV and PEG as a treatment option in ALS. The risk of bronchopneumonia as cause of death may be increased by NIV.

There is growing evidence that microglia are key players in the pathological process of amyotrophic lateral sclerosis (ALS). It is suggested that microglia have a dual role in motoneurone degeneration through the release of both neuroprotective and neurotoxic factors. To identify candidate genes that may be involved in ALS pathology we have analysed at early symptomatic age (P90), the molecular signature of microglia from the lumbar region of the spinal cord of hSOD1G93A mice, the most widely used animal model of ALS. We first identified unique hSOD1G93A microglia transcriptomic profile that, in addition to more classical processes such as chemotaxis and immune response, pointed toward the potential involvement of the tumour suppressor gene breast cancer susceptibility gene 1 (Brca1). Secondly, comparison with our previous data on hSOD1G93A motoneurone gene profile substantiated the putative contribution of Brca1 in ALS. Finally, we established that Brca1 protein is specifically expressed in human spinal microglia and is up-regulated in ALS patients. Overall, our data provide new insights into the pathogenic concept of a non-cell-autonomous disease and the involvement of microglia in ALS. Importantly, the identification of Brca1 as a novel microglial marker and as possible contributor in both human and animal model of ALS may represent a valid therapeutic target. Moreover, our data points toward novel research strategies such as investigating the role of oncogenic proteins in neurodegenerative diseases.

Cannabinoid receptor subtype 2 (CB2) has been shown to be up-regulated in activated microglia and therefore plays an important role in neuroinflammatory and neurodegenerative diseases such as multiple sclerosis, amyotrophic lateral sclerosis and Alzheimer’s disease. The CB2 receptor is therefore considered as a very promising target for therapeutic approaches as well as for imaging. A promising 2-oxoquinoline derivative designated KP23 was synthesized and radiolabeled and its potential as a ligand for PET imaging the CB2 receptor was evaluated. [¹¹C]KP23 was obtained in 10%–25% radiochemical yield (decay corrected) and 99% radiochemical purity. It showed high stability in phosphate buffer, rat and mouse plasma. In vitro autoradiography of rat and mouse spleen slices, as spleen expresses a high physiological expression of CB2 receptors, demonstrated that [¹¹C]KP23 exhibits specific binding towards CB2. High spleen uptake of [¹¹C]KP23 was observed in dynamic in vivo PET studies with Wistar rats. In conclusion, [¹¹C]KP23 showed promising in vitro and in vivo characteristics. Further evaluation with diseased animal model which has higher CB2 expression levels in the brain is warranted.

Cramps are painful, involuntary muscle contractions. They commonly affect people with amyotrophic lateral sclerosis/motor neuron disease (ALS/MND) at all stages of the disease. To date, the treatment of muscle cramps in ALS has been largely empirical without any evidence from randomised controlled trials. To systematically assess the effect of interventions on muscle cramps as a primary or secondary endpoint or adverse event in people with ALS/MND. We searched the Cochrane Neuromuscular Disease Group Specialized Register (14 February 2011), the Cochrane Central Register of Controlled Trials (Issue 1, 2011 in The Cochrane Library), MEDLINE (January 1966 to January 2011) and EMBASE (January 1980 to January 2011) and reference lists of articles searched using the terms motor neuron disease, motor neurone disease, motoneuron disease or amyotrophic lateral sclerosis. We contacted authors of trials for further information. We included all randomised and quasi‐randomised trials of oral medications in people with ALS which assessed cramps as a primary or secondary outcome measure or as an adverse event. We also included trials using subcutaneous or intravenous medications or physical therapy. All authors applied the selection criteria and assessed study quality independently, and all authors performed independent data extraction. Twenty studies including 4789 participants were identified. Only one trial, of tetrahydrocannabinol (THC), assessed cramps as the primary endpoint. Thirteen studies assessed cramps as a secondary endpoint. The medications comprised vitamin E, baclofen, riluzole, L‐threonine, xaliproden, indinavir, and memantine. Six studies assessed cramps as an adverse event. The medications comprised creatine, gabapentin, dextromethorphan, quinidine, and lithium. In all 20 studies no favourable effect for the treatment of cramps in ALS/MND could be demonstrated, but many studies were underpowered to draw a definite conclusion. A meta‐analysis of two small studies showed a statistically nonsignificant result for the amino acid L‐threonine for the treatment of cramps in ALS/MND. No study was identified using physical therapy as a therapeutic intervention for cramps. There is no evidence to support the use of any intervention for muscle cramps in ALS/MND. More and larger randomised controlled trials evaluating treatments for muscle cramps in ALS/MND are needed. Traitement des crampes dans le cas d'une sclérose latérale amyotrophique/maladie du motoneurone Les crampes sont des contractions musculaires involontaires et douloureuses. Elles touchent fréquemment des personnes atteintes de sclérose latérale amyotrophique/maladie du motoneurone (SLA) à tous les stades de la maladie. Jusqu'ici, le traitement des crampes musculaires dans le cas d'une SLA était en grande partie empirique sans aucune preuve provenant des essais contrôlés randomisés. Évaluer systématiquement l'effet des interventions sur les crampes musculaires en tant que critère de jugement principal ou secondaire ou événement indésirable chez les personnes atteintes de SLA/MMN. Nous avons effectué une recherche dans le registre spécialisé du groupe Cochrane sur les affections neuro‐musculaires (14.02.2011), le registre Cochrane des essais contrôlés (CENTRAL) (numéro 1, 2011 dans The Cochrane Library), MEDLINE (de janvier 1966 à janvier 2011) et EMBASE (de janvier 1980 à janvier 2011) et les listes bibliographiques des articles consultés en utilisant les termes maladie du motoneurone, maladie des motoneurones, maladie des neurones moteurs ou sclérose latérale amyotrophique. Nous avons contacté les auteurs des essais pour obtenir des informations supplémentaires. Nous avons inclus tous les essais randomisés et quasi‐randomisés des médicaments oraux portant sur des personnes atteintes de SLA qui évaluaient les crampes en tant que mesure d'un critère de jugement principal ou secondaire ou en tant qu'événement indésirable. Nous avons aussi inclus les essais utilisant des médicaments sous‐cutanés ou intraveineux ou une physiothérapie. Tous les auteurs ont appliqué les critères de sélection et ont évalué la qualité des études de façon indépendante, de même que tous les auteurs ont procédé à l'extraction des données de façon indépendante. Vingt études portant sur 4 789 participants ont été identifiées. Seul un essai, celui du tétrahydrocannabinol (THC), avait évalué les crampes en tant que principal critère de jugement. Treize études avaient évalué les crampes en tant que critère de jugement secondaire. Les médicaments comprenaient la vitamine E, le baclofène, le riluzole, la L‐thréonine, le xaliprodène, l'indinavir et la mémantine. Six études avaient évalué les crampes en tant qu'événement indésirable. Les médicaments comprenaient la créatine, la gabapentine, la dextrométhorphane, la quinidine et le lithium. Dans la totalité des 20 études, aucun effet favorable pour le traitement des crampes dans le cas d'une SLA/MMN n'a pu être démontré, mais de nombreuses études manquaient de puissance pour tirer des conclusions définitives. Une méta‐analyse de deux petites études a montré un résultat statistiquement non significatif pour l'acide aminé L‐thréonine pour le traitement des crampes dans le cas d'une SLA/MMN. Aucune étude utilisant la physiothérapie en tant qu'intervention thérapeutique pour les crampes n'a été identifiée. Il n'existe aucune preuve pour soutenir l'utilisation de toute intervention pour le traitement des crampes musculaires dans le cas d'une SLA/MMN. Des essais contrôlés randomisés supplémentaires et plus importants évaluant les traitements pour les crampes musculaires dans le cas d'une SLA/MMN doivent être effectuées.

Background Many patients with amyotrophic lateral sclerosis (ALS) experience cramps during the course of the disease but so far, none of the medications used has been of proven benefit. The objective was to determine the effect of orally administered tetrahydrocannabinol (THC) on cramps in ALS patients. Methods The authors conducted a randomised, double-blind, placebo-controlled crossover trial in 27 ALS patients suffering from moderate to severe (visual analogue scale (VAS); VAS≥4) daily cramps. There were 7 women and 20 men with a mean age of 57 years and a mean functional ALS score (ALSFRS-R) of 38.4. Patients were randomly assigned to receive 5 mg THC twice daily followed by placebo or vice versa. Each treatment period lasted for 2 weeks and was preceded by a 2-week drug-free observation period (run-in, wash-out period respectively). The primary outcome measure was change in cramp intensity as assessed by a VAS. Secondary outcome measures included the number of cramps per day, number of cramps during daytime and bedtime, intensity of fasciculations (VAS) as well as validated measures of quality of life (ALSAQ-40), quality of sleep (SDQ), appetite (FAACT) and depression (HADS). Results Complete data were available from 22 patients. THC was well tolerated. There was no evidence for a treatment effect on cramp intensity, number of cramps, fasciculation intensity or any of the other secondary outcome measures. Conclusions This interventional study with orally administered THC 5 mg twice daily did not demonstrate subjective improvement of cramp intensity in ALS patients.

The 6th European ALS congress took place in Lisbon, Portugal from 20 to 22 June. The scientific sessions focused on disease pathogenesis and neuroprotection including genetics, proteomics, metabolomics and various disease models. In the clinical session the latest findings on nutrition, ventilation, psychological support as well as new developments in the field of imaging and neurophysiology were discussed. This review outlines the work that was presented during the meeting.

Obwohl nur etwa 10% aller Patienten mit Amyotropher Lateralsklerose (ALS) an einer familiären Form (FALS) leiden, hat die Entdeckung von Mutationen im Kupfer/Zink-Superoxid-Dismutase-Gen (CuZn-SOD) auf dem Chromosom 21q zu enormen Fortschritten in der ALS Forschung geführt. Bislang lässt sich bei ca. 20% aller FALS Patienten eine SOD-Mutation nachweisen, es sind jedoch bereits ein weiteres Gen (ALS2) und sechs weitere Genloci bekannt, deren Identifizierung eine Frage der Zeit ist. Von enormer Wichtigkeit ist ein SOD-Tiermodell, welches sowohl zur Erforschung der Pathogenese als auch für die Entwicklung neuer Therapiestrategien eingesetzt wird. Da auch bei der sporadischen ALS (SALS) Gene, entweder im Zusammenspiel oder durch Umwelteinflüsse kontrolliert pathogenetisch wirksam sind, wird für die Entwicklung wirksamer Therapien die Identifizierung weiterer krankheitsauslösender Gene und die Entwicklung von Tiermodellen entscheidend sein.