Maturation process of TDP-43-positive neuronal cytoplasmic inclusions in amyotrophic lateral sclerosis with and without dementia

2008 ◽  
Vol 116 (2) ◽  
pp. 193-203 ◽  
Author(s):  
Fumiaki Mori ◽  
Kunikazu Tanji ◽  
Hai-Xin Zhang ◽  
Yasushi Nishihira ◽  
Chun-Feng Tan ◽  
...  
2019 ◽  
Vol 79 (3) ◽  
pp. 256-265 ◽  
Author(s):  
Yoshiaki Nakayama ◽  
Kazumi Tsuji ◽  
Takashi Ayaki ◽  
Megumi Mori ◽  
Fuminori Tokunaga ◽  
...  

Abstract Neuronal cytoplasmic inclusions (NCIs) containing TAR DNA-binding protein of 43 kDa (TDP-43) are pathological hallmarks of amyotrophic lateral sclerosis (ALS) and are known to be ubiquitinated. Eight linkage types of polyubiquitin chains have been reported, each type of chain exerting different intracellular actions. The linkage type of polyubiquitin chain involved in the formation of NCIs in sporadic ALS (sALS), however, has not yet been elucidated. We performed immunohistochemical study of the spinal cords of 12 patients with sALS and on those of 6 control subjects. Virtually all ubiquitinated NCIs were immunolabeled with lysine 48-linked polyubiquitin chain (K48-Ub). Although the majority of NCIs were triple-immunoreactive for K48-Ub, linear polyubiquitin chain (L-Ub), and lysine 63-linked polyubiquitin chain (K63-Ub), thin parts of K48-Ub-immunopositive NCIs were not labeled for K63-Ub or L-Ub. We also detected HOIP and SHARPIN, components of linear ubiquitin chain assembly complex, colocalizing with L-Ub on NCIs. Moreover, the immunosignal of optineurin, an autophagy receptor working with L-Ub, and that of activated NF-κB p65, were observed to be colocalizing with L-Ub on certain parts of NCIs. The L-Ub modification of TDP-43-positive NCIs may function as an inducer of autophagic clearance of NCIs, neuroinflammation, and neurodegeneration in sALS.


2015 ◽  
Vol 35 (14) ◽  
pp. 2385-2399 ◽  
Author(s):  
Nadine Bakkar ◽  
Arianna Kousari ◽  
Tina Kovalik ◽  
Yang Li ◽  
Robert Bowser

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the selective loss of motor neurons. Various factors contribute to the disease, including RNA binding protein dysregulation and oxidative stress, but their exact role in pathogenic mechanisms remains unclear. We have recently linked another RNA binding protein, RBM45, to ALS via increased levels of protein in the cerebrospinal fluid of ALS patients and its localization to cytoplasmic inclusions in ALS motor neurons. Here we show RBM45 nuclear exit in ALS spinal cord motor neurons compared to controls, a phenotype recapitulatedin vitroin motor neurons treated with oxidative stressors. We find that RBM45 binds and stabilizes KEAP1, the inhibitor of the antioxidant response transcription factor NRF2. ALS lumbar spinal cord lysates similarly show increased cytoplasmic binding of KEAP1 and RBM45. Binding of RBM45 to KEAP1 impedes the protective antioxidant response, thus contributing to oxidative stress-induced cellular toxicity. Our findings thus describe a novel link between a mislocalized RNA binding protein implicated in ALS (RBM45) and dysregulation of the neuroprotective antioxidant response seen in the disease.


Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1791
Author(s):  
Ana Bajc Česnik ◽  
Helena Motaln ◽  
Boris Rogelj

Amyotrophic lateral sclerosis is a progressive neurodegenerative disorder, characterized by cytoplasmic inclusions of RNA-binding protein TDP-43. Despite decades of research and identification of more than 50 genes associated with amyotrophic lateral sclerosis (ALS), the cause of TDP-43 translocation from the nucleus and its aggregation in the cytoplasm still remains unknown. Our study addressed the impact of selected ALS-associated genes on TDP-43 aggregation behavior in wild-type and aggregation prone TDP-43 in vitro cell models. These were developed by deleting TDP-43 nuclear localization signal and stepwise shortening its low-complexity region. The SH-SY5Y cells were co-transfected with the constructs of aggregation-prone TDP-43 and wild-type or mutant ALS-associated genes hnRNPA1, MATR3, VCP or UBQLN2. The investigated genes displayed a unique impact on TDP-43 aggregation, generating distinct types of cytoplasmic inclusions, similar to those already described as resembling prion strains, which could represent the basis for neurodegenerative disease heterogeneity.


2017 ◽  
Vol 01 (03) ◽  
pp. E136-E141 ◽  
Author(s):  
H. Braak ◽  
M. Neumann ◽  
A. Ludolph ◽  
K. Del Tredici

AbstractThe pathological process underlying sporadic amyotrophic lateral sclerosis (sALS) that is associated with the formation of cytoplasmic inclusions of a nuclear protein (TDP-43) is confined to only a few types of long-axoned projection neurons. The giant Betz pyramidal cells of the primary motor neocortex as well as large α-motor neurons of the lower brainstem and spinal cord become involved early. In the human brain, these 2 neuronal types are to a large extent interconnected by monosynaptic axonal projections. The cell nuclei of affected neurons gradually forfeit their normal expression of the protein TDP-43. In α-motor neurons, this nuclear loss is followed by the formation of insoluble TDP-43-immunopositive inclusions in the cytoplasm, whereas in Betz cells the loss of nuclear expression remains for an unknown period of time unaccompanied by somatodendritic and/or axoplasmic aggregations. It is possible that in cortical pyramidal cells (Betz cells) the nuclear clearing initially leads to the formation of an abnormal but still soluble cytoplasmic TDP-43 which may enter the axoplasm and, following transmission via direct synaptic contacts, induces anew TDP-43 dysregulation and aggregation in recipient neurons. The trajectory of the spreading pattern that consecutively develops during the course of sALS is consistent with the dissemination from chiefly cortical projection neurons via axonal transport through direct synaptic contacts leading to the secondary induction of TDP-43-containing inclusions within recipient nerve cells in involved subcortical regions.


2020 ◽  
Vol 79 (4) ◽  
pp. 370-377 ◽  
Author(s):  
Kensuke Ikenaka ◽  
Shinsuke Ishigaki ◽  
Yohei Iguchi ◽  
Kaori Kawai ◽  
Yusuke Fujioka ◽  
...  

Abstract Alterations of RNA metabolism caused by mutations in RNA-binding protein genes, such as transactivating DNA-binding protein-43 (TDP-43) and fused in sarcoma (FUS), have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Unlike the accumulation of TDP43, which is accepted as a pathological hall mark of sporadic ALS (sALS), FUS pathology in sALS is still under debate. Although immunoreactive inclusions of FUS have been detected in sALS patients previously, the technical limitation of signal detection, including the necessity of specific antigen retrieval, restricts our understanding of FUS-associated ALS pathology. In this study, we applied a novel detection method using a conventional antigen retrieval technique with Sudan Black B treatment to identify FUS-positive inclusions in sALS patients. We classified pathological motor neurons into 5 different categories according to the different aggregation characteristics of FUS and TDP-43. Although the granular type was more dominant for inclusions with TDP-43, the skein-like type was more often observed in FUS-positive inclusions, suggesting that these 2 proteins undergo independent aggregation processes. Moreover, neurons harboring FUS-positive inclusions demonstrated substantially reduced expression levels of dynactin-1, a retrograde motor protein, indicating that perturbation of nucleocytoplasmic transport is associated with the formation of cytoplasmic inclusions of FUS in sALS.


2021 ◽  
Vol 22 (8) ◽  
pp. 3843
Author(s):  
Yuichi Riku ◽  
Danielle Seilhean ◽  
Charles Duyckaerts ◽  
Susana Boluda ◽  
Yohei Iguchi ◽  
...  

Transactivation response DNA binding protein 43 kDa (TDP-43) is known to be a pathologic protein in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). TDP-43 is normally a nuclear protein, but affected neurons of ALS or FTLD patients exhibit mislocalization of nuclear TDP-43 and cytoplasmic inclusions. Basic studies have suggested gain-of-neurotoxicity of aggregated TDP-43 or loss-of-function of intrinsic, nuclear TDP-43. It has also been hypothesized that the aggregated TDP-43 functions as a propagation seed of TDP-43 pathology. However, a mechanistic discrepancy between the TDP-43 pathology and neuronal dysfunctions remains. This article aims to review the observations of TDP-43 pathology in autopsied ALS and FTLD patients and address pathways of neuronal dysfunction related to the neuropathological findings, focusing on impaired clearance of TDP-43 and synaptic alterations in TDP-43-related ALS and FTLD. The former may be relevant to intraneuronal aggregation of TDP-43 and exocytosis of propagation seeds, whereas the latter may be related to neuronal dysfunction induced by TDP-43 pathology. Successful strategies of disease-modifying therapy might arise from further investigation of these subcellular alterations.


Sign in / Sign up

Export Citation Format

Share Document