16 research outputs found
Understanding ALS: insights from genetics, genomics and functional biology
No full textAmyotrophic lateral sclerosis is a progressive neurological disorder. It is characterized by the selective degeneration of central and peripheral motor neurons, leading to muscle wasting and weakness, and subsequent paralysis. Patients die on average 3 to 5 years after disease onset, mostly due to respiratory failure. Progress in understanding the genetic background of ALS has recently begun to improve our understanding of pathogenic changes underlying the disease. However, both at the preclinical and clinical levels, many questions remain to be addressed. In this thesis, we expand the knowledge on ALS pathogenesis by combining different approaches from genetics, genomics and functional biology. First, we used gene expression profiling to study ALS pathogenesis in the SOD1-G93A mouse model of ALS. We show that blood gene expression profiles can be used to distinguish transgenic from wild-type mice by studying overlap and differences in gene expression of different tissues in this mouse model. Also, we used gene expression profiling to study the effect of the only currently available drug for ALS, riluzole, in SOD1-G93A mice. Several pathways were identified as influenced by riluzole treatment, including ubiquitin-mediated proteolysis, RNA-protein interaction and mitochondrial function. Changed RNA-protein interaction has recently emerged as important pathogenic mechanism in ALS. Therefore, we next investigated the occurrence of rare variants in previously ALS-associated genomic regions on human chromosome 9 and 19 and found that rare variants in the coding parts of these regions were not associated with ALS. We have confirmed the presence of FUS variants in a cohort of Dutch ALS patients, at equal frequencies as has been described in other studies. We then focused on further studying cellular mechanisms associated with FUS-caused ALS. ALS-linked mutations in FUS often lead to cytosolic mislocalization of the protein. We therefore performed a protein-interaction screen and determined numerous FUS-interacting proteins, including SMN and FMRP. Both SMN and FMRP are involved in neurological disease (SMA and FXS, respectively) and, in addition, genetic variation in SMN has been shown to be associated with ALS. Genetic variation in FMRP, however, is not associated with ALS, as described in this thesis. Subsequently, we showed that both SMN and FMRP are sequestered into FUS-associated cytosolic protein aggregates in primary neuron models. The sequestration of these proteins into cytosolic protein aggregates leads to their depletion from the axon, the endogenous expression site of the proteins. This impairs their normal function, as both SMN and FMRP have specific axonal functions. Depletion of SMN by ALS-mutant FUS aggregates leads to morphological defects, particularly at the growth cone, in primary cortical neurons. When the effect of protein sequestration of FMRP was studied in a zebrafish model of FUS, we observed a decrease in integrity of the neuromuscular junction. Importantly, each defect could be rescued by restoring expression of SMN and FMRP, respectively. These findings illustrate how protein aggregation in ALS leads to sequestration of proteins, depleting them from endogenous sites of expression and thereby leading to defects in axonal connectivity. Approaches to decrease protein aggregation toxicity and tackle connectivity defects are promising therapeutic strategies for ALS
Multifocal motor neuropathy: Clinical, genetic, and immunological studies
No full textMultifocal motor neuropathy (MMN) is a very rare inflammatory neuropathy that leads to muscle weakness in mainly the hands and feet. IgM antibodies directed against the ganglioside GM1 can be found in at least 50% of patients with MMN, which upon binding to neurons activate the classical pathway of the complement cascade, leading to motor neuron damage. MMN is treatable with intravenous immunoglobulins (IVIg), but its efficacy is usually partial, and many patients will follow a steadily progressive disease course. Therefore, identifying new and more effective treatment strategies for patients with MMN remains important. To achieve this, we need to improve our detailed understanding of the immunopathology underlying MMN. In this thesis, we performed clinical, genetic, and immunological studies in MMN. We showed that despite treatment with IVIg, deterioration of muscle weakness over time is the rule rather than the exception, and identified factors associated with worse disease outcome. Next, we found that MMN is associated with two HLA class II genotypes, and with a polymorphism in the promotor region of the complement regulator CD55, demonstrating genetic susceptibility underlying MMN. We demonstrated that, next to anti-GM1 IgM antibodies, anti-GM2 IgM antibodies are found in a subgroup of patients, extending the repertoire of antibodies associated with MMN. These antibodies specifically bind to Schwann cells, also activate complement, and are associated with an earlier onset of muscle weakness. Finally, we found that MMN is associated with an altered composition of bacteria that constitute the gut microbiome, and found certain alterations to be specifically associated with anti-GM1 IgM antibodies. Together, the studies in this thesis significantly improve our understanding of the immunopathogenesis of MMN, which may hopefully form a basis for the development of novel treatment strategies
Archeologisch vooronderzoek: een inventariserend veldonderzoek (proefsleuven)
No full textIn opdracht van Bouwfonds Ontwikkeling B.V. heeft RAAP Archeologisch Adviesbureau van 13 tot en met 19 februari 2014 in plangebied Heiligerweg te Margraten (gemeente Eijsden-Margraten) een proefsleuvenonderzoek uitgevoerd naar aanleiding van de geplande nieuwbouw (De Bloesemgaard).
Het primaire doel van dit onderzoek was het toetsen en aanvullen van de gespecificeerde archeologische verwachting voor het onderzochte gebied, waarbij het in eerste instantie ging om het (al dan niet) vaststellen van de aanwezigheid van archeologische grond sporen. Voorts diende het onderzoek zich te richten op de aard, omvang, datering, kwaliteit (gaafheid en conservering) en diepteligging van eventueel aanwezige archeologische grondsporen en resten.
Er zijn 16 proefsleuven aangelegd (ca. 3.692 m²) in het plangebied (ca. 6,5 ha). Hierin zijn resten aangetroffen van de volgende vindplaatsen:
- In het uiterste zuidoosten van het plangebied (put 14 en waarschijnlijk ook put 1) zijn neder zettingsresten ([paal]kuilen, een mogelijke haard/meiler en een greppel) uit de Midden Romeinse tijd (2e - 3e eeuw) aangetroffen. Deze resten bevinden zich op het hoogste deel van het plangebied.
- Direct ten noorden van de Heiligerweg, op een lager deel in het plangebied, zijn nederzettingsresten ([paal]kuilen en greppels) uit de Volle Middeleeuwen (11e - 13e eeuw, waarschijnlijk 12e eeuw) aangetroffen.
Daarnaast zijn bij de aanleg en in enkele Romeinse sporen vuurstenen artefacten aangetroffen die vermoedelijk dateren uit het (Midden) Neolithicum. Grondsporen uit deze periode zijn niet aangetroffen. Mogelijk betreft het opspit van een oudere, inmiddels verstoorde/geërodeerde vindplaats.
De Romeinse (ca. 5.270 m², waarvan ca. 716 m² reeds is opgegraven) en middeleeuwse (ca. 6.530 m², waarvan ca. 325 m² is opgegraven) vindplaatsen zijn op basis van hun inhoudelijke kwaliteit behoudenswaardig. Hier wordt in eerste instantie behoud in situ aanbevolen (bijv. door planaanpassing). Indien behoud in situ niet mogelijk is (dat wilt zeggen als er dieper dan 30 cm beneden huidig maaiveld wordt verstoord), dan wordt een vervolgonderzoek aanbevolen in de vorm van een opgraving (zie figuur 7: roze). Bij het onderzoek op de middeleeuwse vindplaats dient aandacht besteed te worden aan de westelijke en oostelijke begrenzing van de vindplaats; mogelijk is de vindplaats kleiner dan nu is aangegeven. Voorafgaand aan een archeologische opgraving dient conform de vigerende versie van de KNA een Programma van Eisen (PvE) te worden opgesteld. Dit PvE dient te worden goedgekeurd door de gemeente (bevoegd gezag).
Ter plaatse van het resterende deel van het plangebied (buiten deze geselecteerde zones) zijn geen archeologische behoudenswaardige vindplaatsen aangetroffen; derhalve kan dit gedeelte van het plangebied worden vrijgegeven voor verdere ontwikkeling (zie figuur 7: groen).
Op basis van de bevindingen van dit onderzoek neemt de gemeente Margraten een selectiebesluit
Understanding the role of UBA1 in the pathogenesis of spinal muscular atrophy
No full textSpinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder
characterized by widespread loss of lower motor neurons from the spinal cord.
Lower motor neuron degeneration leads to a progressive decline in motor
development, manifesting as muscle atrophy and weakness. It is now well
characterised that ubiquitin homeostasis is altered in SMA and that reduction of the
ubiquitin-like modifier-activating enzyme 1 (UBA1) is central to this disruption.
UBA1 is responsible for activating ubiquitin as the first step in the ubiquitin
conjugation process, marking unwanted proteins for degradation by the proteasome.
While it is known that therapies targeting UBA1 rescue neuromuscular phenotypes in
SMA models, the mechanism by which UBA1 mediates neurodegeneration is
unclear. In fact, very little is known about the function of UBA1 beyond its canonical
role in the ubiquitin proteasome system. To better understand the role of UBA1 in
motor neuron degeneration, a robust set of antibodies for both in vivo and in vitro
work to study UBA1 have been identified. This enabled a novel characterisation of
UBA1 distribution throughout disease progression in SMA spinal motor neurons to
be performed, revealing that UBA1 reduction is an important pre-symptomatic
molecular feature of SMA. To identify downstream targets of UBA1 critical for
UBA1-mediated degeneration in SMA, label-free proteomics was performed on
HEK293 cells after overexpression or knockdown of UBA1. The proteomics data
was analysed across multiple platforms, including Biolayout, IPA and DAVID to
identify UBA1-dependent pathways and demonstrated that modulation of UBA1
levels lead to disruption of key cellular pathways including translation elongation,
nuclear transport, and tRNA synthetases. Validation of target proteins from these
UBA1-dependent pathways identified that the tRNA synthetease GARS behaves in a
UBA1-dependent manner across a range of model systems in vitro and in vivo. It was
then identified that GARS expression is significantly dysregulated across a range of
neuronal tissues in a mouse model of SMA. Interestingly, mutations in GARS cause
Charcot-Marie-Tooth disease type 2D (CMT2D), an axonal neuropathy, in which a
disruption to sensory neuron fate in dorsal root ganglia has recently been identified.
In a mouse model of SMA we identified a phenotype consistent with that in the
CMT2D mouse model and showed that disruption to sensory neuron fate is reversible and dependent on changes in UBA1 and GARS expression in SMA. In
conclusion, modulation of UBA1 levels leads to disruption of key cellular pathways,
with dysregulation of tRNA synthetases a prominent feature that is likely to play a
role in the pathogenesis of SMA
Resonant Spaces: Electroacoustic Music and Ritual: A commentary on my recent music.
No full textThe following portfolio and commentary concerns music and performance works created between 2008 and 2012, and an exposition of the research, ideas, aesthetics and techniques that connect
these works. I will discuss in detail the role that archaeoacoustics has played in my composition of fixed and mixed media works and how it has influenced me aesthetically in my approach to live performance. I will also explain in each instance any actual data used from various research sources, and my metaphorical interpretation of various archaeological sites and acoustic phenomena. Similarly, I will discuss the concepts of shamanism, ritual and transcendence that have influenced me, and how these concepts are expressed in my instrumental works, fixed media and live performance pieces
Comparative interactomics analysis of different ALS-associated proteins identifies converging molecular pathways
No full textAmyotrophic lateral sclerosis (ALS) is a devastating neurological disease with no effective treatment available. An increasing number of genetic causes of ALS are being identified, but how these genetic defects lead to motor neuron degeneration and to which extent they affect common cellular pathways remains incompletely understood. To address these questions, we performed an interactomic analysis to identify binding partners of wild-type (WT) and ALS-associated mutant versions of ATXN2, C9orf72, FUS, OPTN, TDP-43 and UBQLN2 in neuronal cells. This analysis identified several known but also many novel binding partners of these proteins. Interactomes of WT and mutant ALS proteins were very similar except for OPTN and UBQLN2, in which mutations caused loss or gain of protein interactions. Several of the identified interactomes showed a high degree of overlap: shared binding partners of ATXN2, FUS and TDP-43 had roles in RNA metabolism; OPTN- and UBQLN2-interacting proteins were related to protein degradation and protein transport, and C9orf72 interactors function in mitochondria. To confirm that this overlap is important for ALS pathogenesis, we studied fragile X mental retardation protein (FMRP), one of the common interactors of ATXN2, FUS and TDP-43, in more detail in in vitro and in vivo model systems for FUS ALS. FMRP localized to mutant FUS-containing aggregates in spinal motor neurons and bound endogenous FUS in a direct and RNA-sensitive manner. Furthermore, defects in synaptic FMRP mRNA target expression, neuromuscular junction integrity, and motor behavior caused by mutant FUS in zebrafish embryos, could be rescued by exogenous FMRP expression. Together, these results show that interactomics analysis can provide crucial insight into ALS disease mechanisms and they link FMRP to motor neuron dysfunction caused by FUS mutations
Angiogenin variants in Parkinson disease and amyotrophic lateral sclerosis.
No full textContains fulltext :
95644.pdf (Publisher’s version ) (Open Access)OBJECTIVE: Several studies have suggested an increased frequency of variants in the gene encoding angiogenin (ANG) in patients with amyotrophic lateral sclerosis (ALS). Interestingly, a few ALS patients carrying ANG variants also showed signs of Parkinson disease (PD). Furthermore, relatives of ALS patients have an increased risk to develop PD, and the prevalence of concomitant motor neuron disease in PD is higher than expected based on chance occurrence. We therefore investigated whether ANG variants could predispose to both ALS and PD. METHODS: We reviewed all previous studies on ANG in ALS and performed sequence experiments on additional samples, which allowed us to analyze data from 6,471 ALS patients and 7,668 controls from 15 centers (13 from Europe and 2 from the USA). We sequenced DNA samples from 3,146 PD patients from 6 centers (5 from Europe and 1 from the USA). Statistical analysis was performed using the variable threshold test, and the Mantel-Haenszel procedure was used to estimate odds ratios. RESULTS: Analysis of sequence data from 17,258 individuals demonstrated a significantly higher frequency of ANG variants in both ALS and PD patients compared to control subjects (p = 9.3 x 10(-6) for ALS and p = 4.3 x 10(-5) for PD). The odds ratio for any ANG variant in patients versus controls was 9.2 for ALS and 6.7 for PD. INTERPRETATION: The data from this multicenter study demonstrate that there is a strong association between PD, ALS, and ANG variants. ANG is a genetic link between ALS and PD. ANN NEUROL 2011;70:964-973.01 december 201110 p
Temporal and tissue-specific variability of SMN protein levels in mouse models of spinal muscular atrophy
No full textSpinal muscular atrophy (SMA) is a progressive motor neuron disease caused by deleterious variants in SMN1 that lead to a marked decrease in survival motor neuron (SMN) protein expression. Humans have a second SMN gene (SMN2) that is almost identical to SMN1. However, due to alternative splicing the majority of SMN2 messenger ribonucleic acid (mRNA) is translated into a truncated, unstable protein that is quickly degraded. Because the presence of SMN2 provides a unique opportunity for therapy development in SMA patients, the mechanisms that regulate SMN2 splicing and mRNA expression have been elucidated in great detail. In contrast, how much SMN protein is produced at different developmental time points and in different tissues remains under-characterized. In this study, we addressed this issue by determining SMN protein expression levels at three developmental time points across six different mouse tissues and in two distinct mouse models of SMA ('severe' Taiwanese and 'intermediate' Smn2B/mice). We found that, in healthy control mice, SMN protein expression was significantly influenced by both age and tissue type.When comparing mouse models of SMA, we found that, despite being transcribed from genetically different alleles, control SMN levels were relatively similar. In contrast, the degree of SMN depletion between tissues in SMA varied substantially over time and between the two models. These findings offer an explanation for the differential vulnerability of tissues and organs observed in SMA and further our understanding of the systemic and temporal requirements for SMN with direct relevance for developing effective therapies for SMA
Systemic restoration of UBA1 ameliorates disease in spinal muscular atrophy
No full textAcknowledgments Blood biochemistry analysis and serum analysis were performed by the Easter Bush Pathology Department, University of Edinburgh. Animal husbandry was performed by Centre for Integrative Physiology bio-research restructure technical staff, University of Edinburgh. Assistance with intravenous injections was provided by Ian Coldicott (University of Sheffield) and Hannah Shorrock (University of Edinburgh). Human blood cDNA was a gift to GH from Kathy Evans, University of Edinburgh. Imaging was performed at the IMPACT imaging facility, University of Edinburgh, with technical assistance from Anisha Kubasik-Thayil. The authors would also like to thank Lyndsay Murray for technical discussions relating to qRT-PCR analysis. This work was supported by funding from the SMA Trust and the Anatomical Society (via grants to THG); the Euan MacDonald Centre for Motor Neurone Disease Research (via grants to THG and SHP); the Wellcome Trust (via grants to EJNG and THG); Muscular Dystrophy UK (via grants to THG and CGB); a Elphinstone Scholarship from the University of Aberdeen (to SHP); and The French Muscular Dystrophy Association (via grants to CM and JC).Peer reviewe
Author Correction: Common and rare variant association analyses in amyotrophic lateral sclerosis identify 15 risk loci with distinct genetic architectures and neuron-specific biology
No full textCorrection to: Nature Genetics https://doi.org/10.1038/s41588-021-00973-1, published online 6 December 2021.
In the version of this article initially published, the affiliation for Nazli Başak appeared incorrectly. Nazli Başak is at Koç University, School of Medicine, KUTTAM-NDAL, Istanbul, Turkey, and not Bogazici University. The error has been corrected in the HTML and PDF versions of the article
