Loss of Tdp-43 disrupts the axonal transcriptome of motoneurons accompanied by impaired axonal translation and mitochondria function
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PROVIDER: PRJNA615680 | ENA |
REPOSITORIES: ENA
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Project description:Protein inclusions containing the RNA-binding protein TDP-43 are a pathological hallmark of amyotrophic lateral sclerosis and other neurodegenerative disorders. The loss of TDP-43 function that is associated with these inclusions affects post-transcriptional processing of RNAs in multiple ways including pre-mRNA splicing, nucleocytoplasmic transport, modulation of mRNA stability and translation. In contrast, less is known about the role of TDP-43 in axonal RNA metabolism in motoneurons. Here we show that depletion of Tdp-43 in primary motoneurons affects axon growth. This defect is accompanied by subcellular transcriptome alterations in the axonal and somatodendritic compartment. The axonal localization of transcripts encoding components of the cytoskeleton, the translational machinery and transcripts involved in mitochondrial energy metabolism were particularly affected by loss of Tdp-43. Accordingly, we observed reduced protein synthesis and disturbed mitochondrial functions in axons of Tdp-43-depleted motoneurons. Treatment with nicotinamide rescued the axon growth defect associated with loss of Tdp-43. These results show that Tdp-43 depletion in motoneurons affects several pathways integral to axon health indicating that loss of TDP-43 function could thus make a major contribution to axonal pathomechanisms in ALS.
2020-07-27 | GSE147607 | GEO
Project description:Mislocalization of the predominantly nuclear RNA/DNA binding protein, TDP-43, occurs in motor neurons of ~95% of ALS patients, but the contribution of axonal TDP-43 to this fatal neurodegenerative disease is unclear. Here, we find TDP-43 accumulation in the axons of intra-muscular nerves from ALS patients, and in motor neurons and neuromuscular junctions(NMJs) of a mouse model with TDP-43 mislocalization. This leads to the formation of G3BP1- and TDP-43-positive RNA-granules in motor neuron axons, and to inhibition of local protein synthesis in axons and NMJs. Specifically, the axonal and synaptic levels of nuclear-encoded mitochondria proteins are reduced. Clearance of axonal TDP-43 restored local translation of the nuclear-encoded mitochondrial proteins and rescued TDP-43-derived axonal and NMJ toxicity. These findings suggest that targeting TDP-43 axonal gain of function may mediata therapeutic effect in ALS.
2021-11-04 | PXD021876 | Pride
Project description:TDP-43, a DNA/RNA binding protein involved in RNA transcription and splicing has been associated with the pathophysiology of neurodegenerative diseases, including ALS. However, the function of TDP-43 in motor neurons remains undefined. Here, we employ both gain- and loss-of-function approaches to determine roles of TDP-43 in motor neurons. Mice expressing human TDP-43 in neurons exhibited growth retardation and premature death that are characterized by abnormal intranuclear inclusions comprised of TDP-43 and Fused in Sarcoma (FUS), and massive accumulation of mitochondria in TDP-43-negative cytoplasmic inclusions in motor neurons, lack of mitochondria in motor axon terminals and immature neuromuscular junctions. Whereas elevated level of TDP-43 disrupts the normal nuclear distribution of Survival Motor Neuron (SMN)-associated Gemini of coiled bodies (GEMs) in motor neurons, its absence prevents the formation of GEMs in the nuclei of these cells. Moreover, transcriptome-wide deep sequencing analysis revealed that decrease in abundance of neurofilament transcripts contributed to the reduction of caliber of motor axons in TDP-43 mice. In concert, our findings indicate that TDP-43 participates in pathways critical for motor neuron physiology, including those that regulate the normal distributions of SMN-associated GEMs in the nucleus and mitochondria in the cytoplasm. Human TDP-43 coding region were inserted into pThy1.2 expression cassette and subsequently injected into C57BL/6;SJL hybrid mouse embryos to make human TDP-43 transgenic mice
2010-07-30 | E-GEOD-22351 | biostudies-arrayexpress
Project description:TDP-43, a DNA/RNA binding protein involved in RNA transcription and splicing has been associated with the pathophysiology of neurodegenerative diseases, including ALS. However, the function of TDP-43 in motor neurons remains undefined. Here, we employ both gain- and loss-of-function approaches to determine roles of TDP-43 in motor neurons. Mice expressing human TDP-43 in neurons exhibited growth retardation and premature death that are characterized by abnormal intranuclear inclusions comprised of TDP-43 and Fused in Sarcoma (FUS), and massive accumulation of mitochondria in TDP-43-negative cytoplasmic inclusions in motor neurons, lack of mitochondria in motor axon terminals and immature neuromuscular junctions. Whereas elevated level of TDP-43 disrupts the normal nuclear distribution of Survival Motor Neuron (SMN)-associated Gemini of coiled bodies (GEMs) in motor neurons, its absence prevents the formation of GEMs in the nuclei of these cells. Moreover, transcriptome-wide deep sequencing analysis revealed that decrease in abundance of neurofilament transcripts contributed to the reduction of caliber of motor axons in TDP-43 mice. In concert, our findings indicate that TDP-43 participates in pathways critical for motor neuron physiology, including those that regulate the normal distributions of SMN-associated GEMs in the nucleus and mitochondria in the cytoplasm.
2010-07-31 | GSE22351 | GEO
Project description:Neuronal function critically depends on coordinated subcellular distribution of mRNAs. Disturbed mRNA processing and axonal transport has been found in spinal muscular atrophy and could be causative for dysfunction and degeneration of motoneurons. Despite the advances made in characterizing the transport mechanisms of several axonal mRNAs, an unbiased approach to identify the axonal repertoire of mRNAs in healthy and degenerating motoneurons has been lacking. Here we used compartmentalized microfluidic chambers to investigate the somatodendritic and axonal mRNA content of cultured motoneurons by microarray analysis. In axons, transcripts related to protein synthesis and energy production were enriched relative to the somatodendritic compartment. Knockdown of Smn, the protein deficient in spinal muscular atrophy, produced a large number of transcript alterations in both compartments. Transcripts related to immune functions, including MHC class I genes, and with roles in RNA splicing were upregulated in the somatodendritic compartment. On the axonal side, transcripts associated with axon growth and synaptic activity were downregulated. These alterations provide evidence that subcellular localization of transcripts with axonal functions as well as regulation of specific transcripts with nonautonomous functions is disturbed in Smn-deficient motoneurons, most likely contributing to the pathophysiology of spinal muscular atrophy.
2014-12-01 | GSE59506 | GEO
Project description:TDP-43 is the major component of pathological inclusions in most ALS patients and in up to 50% of patients with frontotemporal dementia (FTD). Heterozygous missense mutations in TARDBP, the gene encoding TDP-43, are one of the common causes of familial ALS. In this study, we investigate TDP-43 protein behavior in induced pluripotent stem cell (iPSC)-derived motor neurons from three ALS patients with different TARDBP mutations and three healthy controls. TARDPB mutations induce several TDP-43 changes in spinal motor neurons, including cytoplasmic mislocalization and accumulation of insoluble TDP-43, C-terminal fragments and phospho-TDP-43. By generating iPSC lines with allele-specific tagging of TDP-43, we find that mutant TDP-43 initiates the observed disease phenotypes and has an altered interactome as indicated by mass spectrometry-based proteomics. Our findings also indicate that TDP-43 proteinopathy results in a defect in mitochondrial transport. Lastly, proteomics analyses also show that pharmacological inhibition of histone deacetylase 6 (HDAC6) restores the observed TDP-43 pathologies and the axonal mitochondrial motility, suggesting that HDAC6 inhibition may be an interesting therapeutic target for neurodegenerative disorders linked to TDP-43 pathology.
2021-03-15 | PXD023852 | Pride
Project description:Disturbed RNA processing and subcellular transport contribute to the pathomechanisms of motoneuron diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. RNA-binding proteins are involved in these processes, but the mechanisms how they regulate the subcellular diversity of transcriptomes, in particular in axons, are not understood. hnRNP R interacts with several proteins involved in motoneuron diseases. It is located in axons of developing motoneurons and its depletion causes defects in axon growth. Here, we used iCLIP to determine the RNA interactome of hnRNP R in motoneurons. We identified ~3,500 RNA targets, predominantly with functions in synaptic transmission and axon guidance. Among the RNA targets identified by iCLIP, the non-coding RNA 7SK was the top interactor of hnRNP R. We detected 7SK in the nucleus but also in the cytosol of motoneurons. In axons, 7SK localized in close proximity to hnRNP R and depletion of hnRNP R reduced axonal 7SK. Furthermore, suppression of 7SK led to defective axon growth that was accompanied by axonal transcriptome alterations similar to those caused by hnRNP R depletion. Using a series of 7SK deletion mutants we show that the function of 7SK in axon elongation depends on its interaction with hnRNP R but not with the pTEF-B complex involved in transcriptional regulation. These results propose a role of 7SK as essential interactor of hnRNP R to regulate its function in axon maintenance.
2018-03-06 | GSE77101 | GEO
Project description:Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are associated with loss of nuclear TDP-43. Here we identify that TDP-43 regulates expression of the neuronal growth-associated factor stathmin-2. Lowered TDP-43 levels, which reduce its binding to sites within the first intron of stathmin-2 pre-mRNA, uncover a cryptic polyadenylation site whose utilization produces a truncated, non-functional mRNA. Reduced stathmin-2 expression is found in neurons trans-differentiated from patient fibroblasts expressing an ALS-causing TDP-43 mutation, in motor cortex and spinal motor neurons from sporadic ALS patients and familial ALS patients with expansion in C9orf72, and in induced pluripotent stem cell (iPSC)-derived motor neurons depleted of TDP-43. Remarkably, while reduction in TDP-43 is shown to inhibit axonal regeneration of iPSC-derived motor neurons, rescue of stathmin-2 expression restores axonal regenerative capacity. Thus, premature polyadenylation-mediated reduction in stathmin-2 is a hallmark of ALS/FTD that functionally links reduced nuclear TDP-43 function to enhanced neuronal vulnerability.
2019-01-01 | GSE122069 | GEO
Project description:TDP-43 proteinopathies including frontotemporal lobar dementia (FTLD) and amyotrophic lateral sclerosis (ALS) are devastating neurodegenerative disorders characterized by aggregation and mislocalization of the nucleic-acid binding protein TDP-43 and subsequent neuronal dysfunction. Here, we developed an endogenous model of sporadic TDP-43 proteinopathy based on the principle that disease-associated TDP-43 acetylation at lysine 145 (K145) alters TDP-43 conformation, impairs its RNA-binding capacity, and induces downstream mis-regulation of target genes. Expression of aberrant acetylation-mimic TDP-43K145Q resulted in stress-induced phase-separated nuclear TDP-43 foci formation and loss-of-TDP-43-function in mouse primary neurons and human induced pluripotent stem cell (iPSC)-derived neurons. Aged mice harboring the single TDP-43K145Q mutation recapitulate several key hallmarks of neurodegenerative proteinopathies, including progressive TDP-43 phosphorylation and insolubility, cytoplasmic mis-localization, widespread transcriptomic and splicing alterations, and cognitive dysfunction. Our study supports a model in which aberrant TDP-43 acetylation drives neuronal dysfunction and cognitive decline through alternative splicing and transcription of genes important in synaptic plasticity and apoptosis, providing a new paradigm to interrogate FTLD disease mechanisms and uncover disease-modifying therapeutics.
2023-01-09 | GSE216294 | GEO
Project description:TDP-43 is a DNA/RNA-binding protein that regulates gene expression and its malfunction in neurons has been causally associated with multiple neurodegenerative disorders. Although progress has been made in understanding the functions of TDP-43 in neurons, little is known about its role in endothelial cells (ECs), angiogenesis and vascular function. Using inducible EC-specific TDP-43 knockout mice, we show that TDP-43 is required for sprouting angiogenesis, vascular barrier integrity and blood vessel stability. Postnatal EC-specific deletion of TDP-43 leads to retinal hypovascularization due to defects in vessel sprouting associated with reduced EC proliferation and migration. In mature blood vessels, loss of TDP-43 disrupts the blood-brain barrier and triggers vascular degeneration. These vascular defects are associated with an inflammatory response in the central-nervous system with activation of microglia and astrocytes. Mechanistically, deletion of TDP-43 disrupts fibronectin matrix around sprouting vessels and reduces -catenin signaling in ECs. Together, our results indicate that TDP-43 is essential for the formation of a stable and mature vasculature.
2024-02-01 | GSE253868 | GEO