Amyotrophic lateral sclerosis affects cortical and subcortical activity underlying motor inhibition and action monitoring

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by muscular atrophy, spasticity, and bulbar signs caused by loss of upper and lower motor neurons. Evidence suggests that ALS additionally affects other brain areas including premotor cortex and supplementary motor area. Here, we studied movement execution and inhibition in ALS patients using a stop‐signal paradigm and functional magnetic resonance imaging. Seventeen ALS patients and 17 age‐matched healthy controls performed a stop‐signal task that required responding with a button press to a right‐ or left‐pointing black arrow (go‐stimuli). In stop‐trials, a red arrow (stop‐stimulus) was presented shortly after the black arrow indicating to withhold the prepared movement. Patients had by trend higher reaction times in go‐trials but did not differ significantly in their inhibition performance. Patients showed stronger inhibition‐related activity in inferior, superior, and middle frontal gyri as well as in putamen and pallidum. Error‐related activity, conversely, was found to be stronger in healthy controls, particularly in the insula bilaterally. Patients also showed increased activity in the motor cortex during button presses. The results provide evidence for altered prefrontal and subcortical networks underlying motor execution, motor inhibition, and error monitoring in ALS. Hum Brain Mapp 36:2878–2889, 2015. © 2015 Wiley Periodicals, Inc.     

Hsp40 proteins phase separate to chaperone the assembly and maintenance of membraneless organelles

Membraneless organelles contain a wide spectrum of molecular chaperones, indicating their important roles in modulating the metastable conformation and biological function of membraneless organelles. Here we report that class I and II Hsp40 (DNAJ) proteins possess a high ability of phase separation rendered by the flexible G/F-rich region. Different Hsp40 proteins localize in different membraneless organelles. Specifically, human Hdj1 (DNAJB1), a class II Hsp40 protein, condenses in ubiquitin (Ub)-rich nuclear bodies, while Hdj2 (DNAJA1), a class I Hsp40 protein, condenses in nucleoli. Upon stress, both Hsp40 proteins incorporate into stress granules (SGs). Mutations of the G/F-rich region not only markedly impaired Hdj1 phase separation and SG involvement and disrupted the synergistic phase separation and colocalization of Hdj1 and fused in sarcoma (FUS) in cells. Being cophase separated with FUS, Hdj1 stabilized the liquid phase of FUS against proceeding into amyloid aggregation in vitro and alleviated abnormal FUS aggregation in cells. Moreover, Hdj1 uses different domains to chaperone FUS phase separation and amyloid aggregation. This paper suggests that phase separation is an intrinsic property of Hsp40 proteins, which enables efficient incorporation and function of Hsp40 in membraneless organelles and may further mediate the buildup of chaperone network in membraneless organelles.

Membraneless organelles in cells are highly diverse and fulfill important biological functions under both normal and stress conditions (1, 2). Protein phase separation can drive the assembly of membraneless organelles, which incorporates hundreds of different proteins and nucleic acids (3–6). Membraneless organelles feature a physical property in between liquid and solid and present as a metastable state of complex supermolecular assembly (7). The maintenance of membraneless organelles in the liquidlike state rather than spontaneous solidification or dissociation is essential for membraneless organelles to fulfill their biological functions (8, 9). Failure of the conformational maintenance of membraneless organelles results in pathological protein aggregation, which is closely associated with various neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (10–14).Molecular chaperones are key components of the quality control system in cells to maintain protein homeostasis (proteostasis). They assist client proteins in folding and translocation and maintain clients in the native conformation avoiding misfolding and aggregation (15). Proteomic analysis of SGs has identified a wide spectrum of molecular chaperones, including Hsp40 (DNAJ), Hsp70, Hsp90, and small Hsps (5, 16), which indicate the importance of chaperones in the assembly and maintenance of membraneless organelles. Studies on yeast Hsp40 proteins (e.g., Sis1 and Ydj1) reveal that they accumulate in SGs and directly influence the assembly, dynamics and clearance of SGs (17). Human Hsp40 proteins, e.g., Hdj1 (DNAJB1) and Hdj2 (DNAJA1), cannot only inhibit the aggregation of a variety of amyloid proteins including α-synuclein, Τau, and polyQ in vitro (18–20) and rescue the cytotoxicity of polyQ and SG-associated RNA-binding proteins including fused in sarcoma (FUS) and TAR DNA-binding protein 43 (TDP-43) in cellular and animal disease models (21–23). However, the mechanism of how Hsp40s rescue the cytotoxicity of these proteins remains unknown. Moreover, genetic defects of Hsp40 proteins have been identified in neurodegenerative diseases including ALS (24), Parkinson’s disease (25), cerebellar ataxia (26), and distal hereditary motor neuron neuropathy (27). These evidences suggest that Hsp40 proteins play an important role in maintaining the neuronal proteostasis by regulating protein assembly and preventing pathological amyloid aggregation.In this paper, we find that human class I and II Hsp40 proteins—Hdj2 and Hdj1 localize differently in nucleoli and Ub-rich nuclear bodies, respectively, under normal conditions. Under stress, both chaperones condense in SGs in the cytoplasm. We show that the close association of Hdj1 and Hdj2 with various membraneless organelles attributes to their phase separation property via the flexible G/F-rich region, which we show is a common property shared by class I and II Hsp40 proteins in different organisms. Furthermore, we find that Hdj1 synergistically phase separates with FUS and maintains the phase-separated state of FUS from proceeding to amyloid aggregation. Interestingly, Hdj1 employs distinctive mechanisms to chaperone the different states (i.e., soluble and phase-separated states) of FUS. This paper suggests that phase separation renders the localization and function of Hsp40 in various membraneless organelles, which may further recruit cochaperones (e.g., Hsp70) for the function and regulation of membraneless organelles.     

Factors relating to the perceived management of emergency situations: A survey of former Advanced Life Support course participants’ clinical experiences

Background

This study explored individual, team, and setting factors associated with the quality of management of in-hospital emergency situations experienced by former Advanced Life Support (ALS) course participants.

Methods

This study was a survey of former ALS course participants’ long-term experience of management of in-hospital, emergency situations. The survey was carried out in 2012 in Denmark and Norway.

Results

A questionnaire was send to 526 potential responders and (281/479 × 100) 58.7% responded. The results demonstrated that 75% of the emergency situations were perceived as “managed well”. In general, the responders’ confidence in being ALS providers was high, mean 4.3 (SD 0.8), scale 1–5. Significant differences between the perceived “well” and “not well” managed situations were found for all questions, p < 0.001. The largest differences related to perception of co-workers’ ability to apply ALS principles, the team atmosphere and communication. Responders’ ratings of quality of management of emergency situations increased with intensity of setting. However, the ‘clinical setting’ was rated significantly lower as attributor to ability to apply ALS principles compared to ‘co-workers familiarity with ALS principles’, ‘own confidence as ALS-provider’ and ‘own social/inter-personal skills’.

Conclusion

The results of this survey emphasise that ALS providers’ perceived ability to apply ALS skills were substantially affected by teamwork skills and co-workers’ skills. Team related factors associated with successful outcome were related to clear role distribution, clear inter-personal communication and attentive listening, as well as respectful behaviour and positive team atmosphere. Although intensity of setting was attributed to ability to apply ALS principles, this did not affect management of emergency situations to the same extent as individual and team factors.     

Accumulation of Neurofilaments in a Sporadic Case of Amyotrophic Lateral Sclerosis

Abstract: We report a case of sporadic amyotrophic lateral sclerosis (ALS) characterized by a marked accumulation of neurofilaments in the cytoplasm of neurons. The neurofilament was identified by immunohistochemical and electron microscopic studies. The distribution of the accumulation in this case was unique, not only in the motoneurons of the anterior horn but also in the neurons of the other areas of the spinal gray matter, some nuclei in the brain stem, pontine reticular formation, substantia nigra, dentate nucleus in the cerebellum and pyramidal cells in the motor cortex. These observations shed light on the pathogenesis of ALS.     

Neuropeptides and neural cell adhesion molecule (NCAM) in CSF from patients with ALS

In 10 patients with amyotrophic lateral sclerosis (ALS), the CSF content of the neuropeptides vasoactive intestinal polypeptide (VIP) and cholecystokinin (CCK) as well as neural cell adhesion molecule (NCAM) was investigated. Compared with normal controls, no deviations were found in CCK or NCAM, while the values of VIP were significantly lower in ALS patients. This finding may reflect a loss of motor neurons.     

Determination of urine thiocyanate in patients with amyotrophic lateral sclerosis

It has been reported that amyotrophic lateral sclerosis-Parkinsonism-dementia in Guam might be related to the eating of Cycas seeds, which contain cyanide. Based on this assumption, we determined the urinary thiocyanate excretion level in patients with ALS and compared this with that of other neurological diseases. The assay method was designed to use column chromatography with Amberlite IRA 402. The thiocyanate level was determined using pyridine-barbiturate method. The 24-h thiocyanate level was higher in the ALS patients of the middle stages than in the normal control group (Wilcoxon's test, P less than 0.02). There were no significant differences between the ALS patient groups of the early and terminal stages, Kugelberg-Welander disease group, Duchenne type muscular dystrophy group and control group. From these results, we concluded that ALS patients were contaminated with cyanide or thiocyanate and that, along with rapid muscular atrophy, the thiocyanate excretion levels were high.     

Issues & opinion. Neurofilaments,free radicals,excitotoxins, and amyotrophic lateral sclerosis

There is increasing evidence implicating abnormalities of neurofilament function in the pathogenesis of amyotrophic lateral sclerosis (ALS). The observation that the P2 blood protein phenotype is overrepresented in patients with ALS is potentially important, but needs confirmation. It should be shown that this segregation is selective for ALS. If it is, the implications outlined in Meyer's hypothesis will need to be explored, bearing in mind that much of the evidence implicating excitotoins, free redicals, and neurofilaments in familial and sporadic ALS is still circumstantial. Thus the identification of candidate genes, the pursuit of large segregation studies, and identification of specific point mutations, remain key goals in ALS research. © 1995 John Wiley & Sons, Inc.     

Aluminum, calcium, and iron in the spinal cord of patients with sporadic amyotrophic lateral sclerosis using laser microprobe mass spectroscopy: a preliminary study

We measured aluminum (Al), calcium (Ca), and iron (Fe) levels in neuronal cytoplasm and nucleus, capillaries, and neuropil in samples of ventral cervical spinal cord from 5 patients with sporadic amyotrophic lateral sclerosis (ALS) and 5 age-matched controls using laser microprobe mass spectrometry (LMMS). The concentration of Al was not altered in any area in the ALS samples. In contrast, Fe and Ca were increased 1.5-2-fold in the nucleus and cytoplasm of ALS neurons but not in capillaries and neuropil. These findings do not support the hypothesis that Al is enriched in spinal cord of sporadic ALS as has been reported for Guamanian ALS/Parkinson's dementia. The elevations of Fe in spinal neurons are consistent with reports of increased Fe in bulk samples of ALS spinal cord. The presence of increased Fe within spinal neurons may be significant in the pathogenesis of motor neuron degeneration by catalyzing the generation of reactive oxygen species within specific cells.     

Management of oral-pharyngeal dysphagia symptoms in amyotrophic lateral sclerosis

Oral and pharyngeal dysphagia is a common symptom in patients with amyotrophic lateral sclerosis (ALS) and is the result of a progressive loss of function in bulbar and respiratory muscles. Clinicians involved in the management of ALS patients should be familiar with the common clinical findings and the usual patterns of temporal progression. The prevention of secondary complications, such as nutritional deficiency and dehydration that compound the deteriorating effects of the disease, requires careful monitoring of each patient's functional status and timely intervention with appropriate management techniques.