scholarly journals MCP1-CCR2 and neuroinflammation in the ALS motor cortex with TDP-43 pathology

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Javier H. Jara ◽  
Mukesh Gautam ◽  
Nuran Kocak ◽  
Edward F. Xie ◽  
Qinwen Mao ◽  
...  

Abstract Background The involvement of non-neuronal cells and the cells of innate immunity has been attributed to the initiation and progression of ALS. TDP-43 pathology is observed in a broad spectrum of ALS cases and is one of the most commonly shared pathologies. The potential involvement of the neuroimmune axis in the motor cortex of ALS patients with TDP-43 pathology needs to be revealed. This information is vital for building effective treatment strategies. Methods We investigated the presence of astrogliosis and microgliosis in the motor cortex of ALS patients with TDP-43 pathology. prpTDP-43A315T-UeGFP mice, corticospinal motor neuron (CSMN) reporter line with TDP-43 pathology, are utilized to reveal the timing and extent of neuroimmune interactions and the involvement of non-neuronal cells to neurodegeneration. Electron microscopy and immunolabeling techniques are used to mark and monitor cells of interest. Results We detected both activated astrocytes and microglia, especially rod-like microglia, in the motor cortex of patients and TDP-43 mouse model. Besides, CCR2+ TMEM119- infiltrating monocytes were detected as they penetrate the brain parenchyma. Interestingly, Betz cells, which normally do not express MCP1, were marked with high levels of MCP1 expression when diseased. Conclusions There is an early contribution of a neuroinflammatory response for upper motor neuron (UMN) degeneration with respect to TDP-43 pathology, and MCP1-CCR2 signaling is important for the recognition of diseased upper motor neurons by infiltrating monocytes. The findings are conserved among species and are observed in both ALS and ALS-FTLD patients.

2018 ◽  
Author(s):  
Silas Maniatis ◽  
Tarmo Äijö ◽  
Sanja Vickovic ◽  
Catherine Braine ◽  
Kristy Kang ◽  
...  

AbstractParalysis occurring in amyotrophic lateral sclerosis (ALS) results from denervation of skeletal muscle as a consequence of motor neuron degeneration. Interactions between motor neurons and glia contribute to motor neuron loss, but the spatiotemporal ordering of molecular events that drive these processes in intact spinal tissue remains poorly understood. Here, we use spatial transcriptomics to obtain gene expression measurements of mouse spinal cords over the course of disease, as well as of postmortem tissue from ALS patients, to characterize the underlying molecular mechanisms in ALS. We identify novel pathway dynamics, regional differences between microglia and astrocyte populations at early time-points, and discern perturbations in several transcriptional pathways shared between murine models of ALS and human postmortem spinal cords.One Sentence SummaryAnalysis of the ALS spinal cord using Spatial Transcriptomics reveals spatiotemporal dynamics of disease driven gene regulation.


Author(s):  
Martin R. Turner

Motor neuron disease (MND) is characterized by progressive muscular weakness due to simultaneous degeneration of lower and upper motor neurons (L/UMNs). Involvement of LMNs, arising from the anterior horns of the spinal cord and brainstem, leads to secondary wasting as a result of muscle denervation. Involvement of the UMNs of the motor cortex and corticospinal tract results in spasticity. In ~85% of cases, there is clear clinical involvement of both, and the condition is termed ‘amyotrophic lateral sclerosis’ (ALS; a term often used synonymously with MND). In ~13% of cases, there may be only LMN signs apparent, in which case the condition is termed ‘progressive muscular atrophy’, although such cases have a natural history that is to largely identical to that of ALS. In a very small group of patients (~2%), there are only UMN signs for at least the first 4 years, in which case the condition is termed ‘primary lateral sclerosis’; such cases have a uniformly slower progression. There is clinical, neuropathological, and genetic overlap between MND and some forms of frontotemporal dementia.


Science ◽  
2019 ◽  
Vol 364 (6435) ◽  
pp. 89-93 ◽  
Author(s):  
Silas Maniatis ◽  
Tarmo Äijö ◽  
Sanja Vickovic ◽  
Catherine Braine ◽  
Kristy Kang ◽  
...  

Paralysis occurring in amyotrophic lateral sclerosis (ALS) results from denervation of skeletal muscle as a consequence of motor neuron degeneration. Interactions between motor neurons and glia contribute to motor neuron loss, but the spatiotemporal ordering of molecular events that drive these processes in intact spinal tissue remains poorly understood. Here, we use spatial transcriptomics to obtain gene expression measurements of mouse spinal cords over the course of disease, as well as of postmortem tissue from ALS patients, to characterize the underlying molecular mechanisms in ALS. We identify pathway dynamics, distinguish regional differences between microglia and astrocyte populations at early time points, and discern perturbations in several transcriptional pathways shared between murine models of ALS and human postmortem spinal cords.


2020 ◽  
Author(s):  
◽  
Loren Ornelas ◽  
Emilda Gomez ◽  
Lindsay Panther ◽  
Aaron Frank ◽  
...  

SummaryNeurodegenerative diseases present a challenge for systems biology, due to the lack of reliable animal models and the difficulties in obtaining samples from patients at early stages of disease, when interventions might be most effective. Studying induced pluripotent stem cell (iPSC)-derived neurons could overcome these challenges and dramatically accelerate and broaden therapeutic strategies. Here we undertook a network-based multi-omic characterization of iPSC-derived motor neurons from ALS patients carrying genetically dominant hexanucleotide expansions in C9orf72 to gain a deeper understanding of the relationship between DNA, RNA, epigenetics and protein in the same pool of tissue. ALS motor neurons showed the expected C9orf72-related alterations to specific nucleoporins and production of dipeptide repeats. RNA-seq, ATAC-seq and data-independent acquisition mass-spectrometry (DIA-MS) proteomics were then performed on the same motor neuron cultures. Using integrative computational methods that combined all of the omics, we discovered a number of novel dysregulated pathways including biological adhesion and extracellular matrix organization and disruption in other expected pathways such as RNA splicing and nuclear transport. We tested the relevance of these pathways in vivo in a C9orf72 Drosophila model, analyzing the data to determine which pathways were causing disease phenotypes and which were compensatory. We also confirmed that some pathways are altered in late-stage neurodegeneration by analyzing human postmortem C9 cervical spine data. To validate that these key pathways were integral to the C9 signature, we prepared a separate set of C9orf72 and control motor neuron cultures using a different differentiation protocol and applied the same methods. As expected, there were major overall differences between the differentiation protocols, especially at the level of in individual omics data. However, a number of the core dysregulated pathways remained significant using the integrated multiomic analysis. This new method of analyzing patient specific neural cultures allows the generation of disease-related hypotheses with a small number of patient lines which can be tested in larger cohorts of patients.


2019 ◽  
Vol 20 (16) ◽  
pp. 3848 ◽  
Author(s):  
Baris Genc ◽  
Oge Gozutok ◽  
P. Hande Ozdinler

Motor neuron circuitry is one of the most elaborate circuitries in our body, which ensures voluntary and skilled movement that requires cognitive input. Therefore, both the cortex and the spinal cord are involved. The cortex has special importance for motor neuron diseases, in which initiation and modulation of voluntary movement is affected. Amyotrophic lateral sclerosis (ALS) is defined by the progressive degeneration of both the upper and lower motor neurons, whereas hereditary spastic paraplegia (HSP) and primary lateral sclerosis (PLS) are characterized mainly by the loss of upper motor neurons. In an effort to reveal the cellular and molecular basis of neuronal degeneration, numerous model systems are generated, and mouse models are no exception. However, there are many different levels of complexities that need to be considered when developing mouse models. Here, we focus our attention to the upper motor neurons, which are one of the most challenging neuron populations to study. Since mice and human differ greatly at a species level, but the cells/neurons in mice and human share many common aspects of cell biology, we offer a solution by focusing our attention to the affected neurons to reveal the complexities of diseases at a cellular level and to improve translational efforts.


2019 ◽  
Vol 116 (10) ◽  
pp. 4696-4705 ◽  
Author(s):  
Joy Mitra ◽  
Erika N. Guerrero ◽  
Pavana M. Hegde ◽  
Nicole F. Liachko ◽  
Haibo Wang ◽  
...  

Genome damage and their defective repair have been etiologically linked to degenerating neurons in many subtypes of amyotrophic lateral sclerosis (ALS) patients; however, the specific mechanisms remain enigmatic. The majority of sporadic ALS patients feature abnormalities in the transactivation response DNA-binding protein of 43 kDa (TDP-43), whose nucleo-cytoplasmic mislocalization is characteristically observed in spinal motor neurons. While emerging evidence suggests involvement of other RNA/DNA binding proteins, like FUS in DNA damage response (DDR), the role of TDP-43 in DDR has not been investigated. Here, we report that TDP-43 is a critical component of the nonhomologous end joining (NHEJ)-mediated DNA double-strand break (DSB) repair pathway. TDP-43 is rapidly recruited at DSB sites to stably interact with DDR and NHEJ factors, specifically acting as a scaffold for the recruitment of break-sealing XRCC4-DNA ligase 4 complex at DSB sites in induced pluripotent stem cell-derived motor neurons. shRNA or CRISPR/Cas9-mediated conditional depletion of TDP-43 markedly increases accumulation of genomic DSBs by impairing NHEJ repair, and thereby, sensitizing neurons to DSB stress. Finally, TDP-43 pathology strongly correlates with DSB repair defects, and damage accumulation in the neuronal genomes of sporadic ALS patients and inCaenorhabditis elegansmutant with TDP-1 loss-of-function. Our findings thus link TDP-43 pathology to impaired DSB repair and persistent DDR signaling in motor neuron disease, and suggest that DSB repair-targeted therapies may ameliorate TDP-43 toxicity-induced genome instability in motor neuron disease.


2007 ◽  
Vol 97 (1) ◽  
pp. 70-82 ◽  
Author(s):  
Marc H. Schieber ◽  
Gil Rivlis

Primary motor cortex (M1) neurons traditionally have been viewed as “upper motor neurons” that directly drive spinal motoneuron pools, particularly during finger movements. We used spike-triggered averages (SpikeTAs) of electromyographic (EMG) activity to select M1 neurons whose spikes signaled the arrival of input in motoneuron pools, and examined the degree of similarity between the activity patterns of these M1 neurons and their target muscles during 12 individuated finger and wrist movements. Neuron–EMG similarity generally was low. Similarity was unrelated to the strength of the SpikeTA effect, to whether the effect was pure versus synchrony, or to the number of muscles influenced by the neuron. Nevertheless, the sum of M1 neuron activity patterns, each weighted by the sign and strength of its SpikeTA effect, could be more similar to the EMG than the average similarity of individual neurons. Significant correlations between the weighted sum of M1 neuron activity patterns and EMG were obtained in six of 17 muscles, but showed R2 values ranging from only 0.26 to 0.42. These observations suggest that additional factors—including inputs from sources other than M1 and nonlinear summation of inputs to motoneuron pools—also contributed substantially to EMG activity patterns. Furthermore, although each of these M1 neurons produced SpikeTA effects with a significant peak or trough 6–16 ms after the triggering spike, shifting the weighted sum of neuron activity to lead the EMG by 40–60 ms increased their similarity, suggesting that the influence of M1 neurons that produce SpikeTA effects includes substantial synaptic integration that in part may reach the motoneuron pools over less-direct pathways.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Jurate Lasiene ◽  
Koji Yamanaka

Amyotrophic lateral sclerosis (ALS) is an adult motor neuron disease characterized by premature death of upper and lower motor neurons. Two percent of ALS cases are caused by the dominant mutations in the gene for superoxide dismutase 1 (SOD1) through a gain of toxic property of mutant protein. Genetic and chimeric mice studies using SOD1 models indicate that non-neuronal cells play important roles in neurodegeneration through non-cell autonomous mechanism. We review the contribution of each glial cell type in ALS pathology from studies of the rodent models and ALS patients. Astrogliosis and microgliosis are not only considerable hallmarks of the disease, but the intensity of microglial activation is correlated with severity of motor neuron damage in human ALS. The impaired astrocytic functions such as clearance of extracellular glutamate and release of neurotrophic factors are implicated in disease. Further, the damage within astrocytes and microglia is involved in accelerated disease progression. Finally, other glial cells such as NG2 cells, oligodendrocytes and Schwann cells are under the investigation to determine their contribution in ALS. Accumulating knowledge of active role of glial cells in the disease should be carefully applied to understanding of the sporadic ALS and development of therapy targeted for glial cells.


2020 ◽  
Author(s):  
Alison L. Hogan ◽  
Natalie Grima ◽  
Jennifer A. Fifita ◽  
Emily P. McCann ◽  
Benjamin Heng ◽  
...  

AbstractBackgroundSplicing factor proline and glutamine rich (SFPQ, also known as polypyrimidine tract-binding protein-associated-splicing factor, PSF) is a RNA-DNA binding protein with roles in key cellular pathways such as DNA transcription and repair, RNA processing and paraspeckle formation. Dysregulation of SFPQ is emerging as a common pathological feature of multiple neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). Increased retention of SFPQ intron nine and nuclear loss of the protein have been linked to multiple genetic subtypes of ALS. Consequently, SFPQ dysregulation has been hypothesised to be a common pathological feature of this highly heterogeneous disease.MethodsThis study provides a comprehensive assessment of SFPQ pathology in large ALS patient cohorts. SFPQ gene expression and intron nine retention were examined in multiple neuroanatomical regions and blood from ALS patients and control individuals using RNA sequencing (RNA-Seq) and quantitative PCR (RT-qPCR). SFPQ protein levels were assessed by immunoblotting of patient and control motor cortex and SFPQ expression pattern was examined by immunofluorescent staining of patient and control spinal cord sections. Finally, whole-genome sequencing data from a large cohort of sporadic ALS patients was analysed for genetic variation in SFPQ.ResultsSFPQ intron nine retention was significantly increased in ALS patient motor cortex. Total SFPQ mRNA expression was significantly downregulated in ALS patient motor cortex but not ALS patient blood, indicating tissue specific SFPQ dysregulation. At the protein level, nuclear expression of SFPQ in both control and patient spinal motor neurons was highly variable and nuclear depletion of SFPQ was not a consistent feature in our ALS cohort. However, we did observe SFPQ-positive cytoplasmic ubiquitinated protein aggregates in ALS spinal motor neurons. In addition, our genetic screen of ALS patients identified two novel, and two rare sequence variants in SFPQ not previously reported in ALS.ConclusionsThis study shows that dysregulation of SFPQ is a feature of ALS patient central nervous system tissue. These findings confirm SFPQ pathology as a feature of ALS and indicate that investigations into the functional consequences of this pathology will provide insight into the biology of ALS.


Author(s):  
Nimish Thakore ◽  
Erik P Pioro

Disorders of lower motor neurons (LMNs, or anterior horn cells) and upper motor neurons (UMNs), jointly termed motor neuron disorders (MNDs), are diverse and numerous. The prototypical MND, namely amyotrophic lateral sclerosis (ALS), a relentlessly progressive lethal disorder of adults, is the subject of another section and will not be discussed further here. Other MNDs include spinal muscular atrophy (SMA), of which there are four types: Kennedy’s disease, Brown-Violetto-Van Laere, and Fazio-Londe syndromes, lower motor neuron disorders as part of neurodegenerations and secondary motor neuron disease as part of malignancy, radiation and infection.


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