Biology subjects

Weishaupt, J. H.

Publications and source records attributed to Weishaupt, J. H..

4 recordsLinked to original sources

bioRxiv2025

Targeted plasma proteomics uncover novel proteins associated with KIF5A-linked SPG10 and ALS spectrum disorders

KIF5A (Kinesin family member 5A) is a motor protein that functions as a key component of the axonal transport machinery. Variants in KIF5A are linked to several neurodegenerative diseases, mainly spastic paraplegia type 10 (SPG10), Charcot-Marie-Tooth disease type 2 (CMT2), and amyotrophic lateral sclerosis (ALS). These diseases share motor neuron involvement but vary significantly in clinical presentation, severity, and progression. KIF5A variants are mainly categorized into N-terminal variants associated with SPG10/CMT2 and C-terminal variants linked to ALS. This study utilized a novel multiplex NULISA targeted platform to analyze plasma proteome from KIF5A-linked SPG10, ALS patients and compared to healthy controls. Our results revealed distinct proteomic signatures, with significant alterations in proteins related to synaptic function, and inflammation. Notably, neurofilament light polypeptide, a biomarker for neurodegenerative diseases, was elevated in KIF5A ALS but not in SPG10 patients. Moreover, these findings can now be taken forward to gain mechanistic understanding of axonopathies linking to N-vs C-terminal KIF5A variants affecting both central and peripheral nervous systems.

neuroscience↗

bioRxiv2025

Somatic mutations in ALS genes in the motor cortex of sporadic ALS patients

Amyotrophic lateral sclerosis (ALS) is characterized by the progressive degeneration of cortical and spinal motor neurons. Mendelian germline mutations often cause familial ALS (fALS) but only approximately ten percent of sporadic ALS cases (sALS). We leveraged DNA and single cell RNA-sequencing data from autopsy tissue to explore the presence of somatic mosaic variants in sALS cases. Deep targeted panel sequencing of known ALS disease genes in motor cortex tissue revealed an enrichment of low allele frequency variants in sALS, but not in fALS with an identified monogenic cause. In silico analysis predicted increased pathogenicity of mosaic mutations in various known ALS mutational hot spots. In particular, we identified the somatic FUS variant p.E516X, located in an established hot spot for germline ALS mutations, which leads to nucleo-cytoplasmic mislocalization and aggregation typical for ALS FUS pathology. Additionally, we performed somatic variant calling on single cell RNA-sequencing data from sALS tissue and revealed a specific accumulation of somatic variants in excitatory neurons, reinforcing a neuron-autonomous disease initiation. Collectively, this study indicates that somatic mutations within the motor cortex, especially in excitatory neurons, may contribute to sALS development.

genetics↗

bioRxiv2022

Molecular dynamics analysis of Superoxide Dismutase 1 mutations suggests decoupling between mechanisms underlying ALS onset and progression

Mutations in the superoxide dismutase 1 (SOD1) gene are the second most common known cause of ALS. SOD1 variants express high phenotypic variability and over 200 have been reported in people with ALS. Investigating how different SOD1 variants affect the protein dynamics might help in understanding their pathogenic mechanism and explaining their heterogeneous clinical presentation. It was previously proposed that variants can be broadly classified in two groups, wild-type like (WTL) and metal binding region (MBR) variants, based on their structural location and biophysical properties. MBR variants are associated with a loss of SOD1 enzymatic activity. In this study we used molecular dynamics and large clinical datasets to characterise the differences in the structural and dynamic behaviour of WTL and MBR variants with respect to the wild-type SOD1, and how such differences influence the ALS clinical phenotype. Our study identified marked structural differences, some of which are observed in both variant groups, while others are group specific. Moreover, applying graph theory to a network representation of the proteins, we identified differences in the intramolecular contacts of the two classes of variants. Finally, collecting clinical data of approximately 500 SOD1 ALS patients carrying variants from both classes, we showed that the survival time of patients carrying an MBR variant is generally longer (~6 years median difference, p < 0.001) with respect to patients with a WTL variant. In conclusion, our study highlights key differences in the dynamic behaviour of the WTL and MBR SOD1 variants, and wild-type SOD1 at an atomic and molecular level. We identified interesting structural features that could be further investigated to explain the associated phenotypic variability. Our results support the hypothesis of a decoupling between mechanisms of onset and progression of SOD1 ALS, and an involvement of loss-of-function of SOD1 with the disease progression.

neuroscience↗

bioRxiv2022

Stress induced TDP-43 mobility loss independent of stress granules

TAR DNA binding protein 43 (TDP-43) is closely related to the pathogenesis of amyotrophic lateral sclerosis (ALS) and translocates to stress granules (SGs). The role of SGs as aggregation-promoting "bioreactors" for TDP-43, however, is still under debate. We analyzed TDP-43 mobility and localization under different stress and recovery conditions using live cell single-molecule tracking and super-resolution microscopy. Besides reduced mobility within SGs, a stress induced decrease of TDP-43 mobility in the cytoplasm and the nucleus was observed. Stress removal led to a recovery of TDP-43 mobility, which strongly depended on the stress duration. Stimulated-emission depletion microscopy (STED) and tracking and localization microscopy (TALM) revealed not only TDP-43 substructures within stress granules but also numerous patches of slow TDP-43 species throughout the cytoplasm. The data provide new insights into the aggregation of TDP-43 in living cells and provide evidence suggesting that TDP-43 oligomerization takes place in the cytoplasm separate from SGs.

biophysics↗