scholarly journals Characterization of LAMP1-labeled nondegradative lysosomal and endocytic compartments in neurons

2018 ◽  
Vol 217 (9) ◽  
pp. 3127-3139 ◽  
Author(s):  
Xiu-Tang Cheng ◽  
Yu-Xiang Xie ◽  
Bing Zhou ◽  
Ning Huang ◽  
Tamar Farfel-Becker ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Distribution Patterns ◽  
Confocal Imaging ◽  
Lysosomal Hydrolases ◽  
Differential Distribution ◽  
Gradient Fractionation ◽  
Endocytic Compartments ◽  
Lateral Sclerosis

Despite widespread distribution of LAMP1 and the heterogeneous nature of LAMP1-labeled compartments, LAMP1 is routinely used as a lysosomal marker, and LAMP1-positive organelles are often referred to as lysosomes. In this study, we use immunoelectron microscopy and confocal imaging to provide quantitative analysis of LAMP1 distribution in various autophagic and endolysosomal organelles in neurons. Our study demonstrates that a significant portion of LAMP1-labeled organelles do not contain detectable lysosomal hydrolases including cathepsins D and B and glucocerebrosidase. A bovine serum albumin–gold pulse–chase assay followed by ultrastructural analysis suggests a heterogeneity of degradative capacity in LAMP1-labeled endolysosomal organelles. Gradient fractionation displays differential distribution patterns of LAMP1/2 and cathepsins D/B in neurons. We further reveal that LAMP1 intensity in familial amyotrophic lateral sclerosis–linked motor neurons does not necessarily reflect lysosomal deficits in vivo. Our study suggests that labeling a set of lysosomal hydrolases combined with various endolysosomal markers would be more accurate than simply relying on LAMP1/2 staining to assess neuronal lysosome distribution, trafficking, and functionality under physiological and pathological conditions.

scholarly journals LanCL1 promotes motor neuron survival and extends the lifespan of amyotrophic lateral sclerosis mice

2019 ◽  
Vol 27 (4) ◽  
pp. 1369-1382 ◽  
Author(s):  
Honglin Tan ◽  
Mina Chen ◽  
Dejiang Pang ◽  
Xiaoqiang Xia ◽  
Chongyangzi Du ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Neuronal Survival ◽  
Disease Onset ◽  
Alternative Mechanism ◽  
Specific Expression ◽  
Motor Neuron Survival ◽  
Lateral Sclerosis

Abstract Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive loss of motor neurons. Improving neuronal survival in ALS remains a significant challenge. Previously, we identified Lanthionine synthetase C-like protein 1 (LanCL1) as a neuronal antioxidant defense gene, the genetic deletion of which causes apoptotic neurodegeneration in the brain. Here, we report in vivo data using the transgenic SOD1G93A mouse model of ALS indicating that CNS-specific expression of LanCL1 transgene extends lifespan, delays disease onset, decelerates symptomatic progression, and improves motor performance of SOD1G93A mice. Conversely, CNS-specific deletion of LanCL1 leads to neurodegenerative phenotypes, including motor neuron loss, neuroinflammation, and oxidative damage. Analysis reveals that LanCL1 is a positive regulator of AKT activity, and LanCL1 overexpression restores the impaired AKT activity in ALS model mice. These findings indicate that LanCL1 regulates neuronal survival through an alternative mechanism, and suggest a new therapeutic target in ALS.

scholarly journals AAV9-mediated delivery of miR-23a reduces disease severity in Smn2B/−SMA model mice

2019 ◽  
Vol 28 (19) ◽  
pp. 3199-3210 ◽  
Author(s):  
Kevin A Kaifer ◽  
Eric Villalón ◽  
Benjamin S O'Brien ◽  
Samantha L Sison ◽  
Caley E Smith ◽  
...  
Keyword(s):  
Motor Neuron ◽  
Motor Neurons ◽  
Molecular Mechanisms ◽  
Viral Vector ◽  
Muscular Atrophy ◽  
Induced Pluripotent Stem Cell ◽  
Survival Motor Neuron ◽  
Virus Serotype

Abstract Spinal muscular atrophy (SMA) is a neuromuscular disease caused by deletions or mutations in survival motor neuron 1 (SMN1). The molecular mechanisms underlying motor neuron degeneration in SMA remain elusive, as global cellular dysfunction obscures the identification and characterization of disease-relevant pathways and potential therapeutic targets. Recent reports have implicated microRNA (miRNA) dysregulation as a potential contributor to the pathological mechanism in SMA. To characterize miRNAs that are differentially regulated in SMA, we profiled miRNA levels in SMA induced pluripotent stem cell (iPSC)-derived motor neurons. From this array, miR-23a downregulation was identified selectively in SMA motor neurons, consistent with previous reports where miR-23a functioned in neuroprotective and muscle atrophy-antagonizing roles. Reintroduction of miR-23a expression in SMA patient iPSC-derived motor neurons protected against degeneration, suggesting a potential miR-23a-specific disease-modifying effect. To assess this activity in vivo, miR-23a was expressed using a self-complementary adeno-associated virus serotype 9 (scAAV9) viral vector in the Smn2B/− SMA mouse model. scAAV9-miR-23a significantly reduced the pathology in SMA mice, including increased motor neuron size, reduced neuromuscular junction pathology, increased muscle fiber area, and extended survival. These experiments demonstrate that miR-23a is a novel protective modifier of SMA, warranting further characterization of miRNA dysfunction in SMA.

scholarly journals Glial Cells—The Strategic Targets in Amyotrophic Lateral Sclerosis Treatment

2020 ◽  
Vol 9 (1) ◽  
pp. 261 ◽  
Author(s):  
Tereza Filipi ◽  
Zuzana Hermanova ◽  
Jana Tureckova ◽  
Ondrej Vanatko ◽  
Miroslava Anderova
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Current Knowledge ◽  
Gene Mutations ◽  
Cell Types ◽  
In Vivo Models ◽  
Cell Therapies ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease, which is characterized by the degeneration of motor neurons in the motor cortex and the spinal cord and subsequently by muscle atrophy. To date, numerous gene mutations have been linked to both sporadic and familial ALS, but the effort of many experimental groups to develop a suitable therapy has not, as of yet, proven successful. The original focus was on the degenerating motor neurons, when researchers tried to understand the pathological mechanisms that cause their slow death. However, it was soon discovered that ALS is a complicated and diverse pathology, where not only neurons, but also other cell types, play a crucial role via the so-called non-cell autonomous effect, which strongly deteriorates neuronal conditions. Subsequently, variable glia-based in vitro and in vivo models of ALS were established and used for brand-new experimental and clinical approaches. Such a shift towards glia soon bore its fruit in the form of several clinical studies, which more or less successfully tried to ward the unfavourable prognosis of ALS progression off. In this review, we aimed to summarize current knowledge regarding the involvement of each glial cell type in the progression of ALS, currently available treatments, and to provide an overview of diverse clinical trials covering pharmacological approaches, gene, and cell therapies.

scholarly journals Neuronal over-expression of Oxr1 is protective against ALS-associated mutant TDP-43 mislocalisation in motor neurons and neuromuscular defects in vivo

2019 ◽  
Vol 28 (21) ◽  
pp. 3584-3599 ◽  
Author(s):  
Matthew G Williamson ◽  
Mattéa J Finelli ◽  
James N Sleigh ◽  
Amy Reddington ◽  
David Gordon ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Gene Encoding ◽  
Over Expression ◽  
Neuromuscular Abnormalities ◽  
And Function ◽  
Lateral Sclerosis

Abstract A common pathological hallmark of amyotrophic lateral sclerosis (ALS) and the related neurodegenerative disorder frontotemporal dementia, is the cellular mislocalization of transactive response DNA-binding protein 43 kDa (TDP-43). Additionally, multiple mutations in the TARDBP gene (encoding TDP-43) are associated with familial forms of ALS. While the exact role for TDP-43 in the onset and progression of ALS remains unclear, the identification of factors that can prevent aberrant TDP-43 localization and function could be clinically beneficial. Previously, we discovered that the oxidation resistance 1 (Oxr1) protein could alleviate cellular mislocalization phenotypes associated with TDP-43 mutations, and that over-expression of Oxr1 was able to delay neuromuscular abnormalities in the hSOD1G93A ALS mouse model. Here, to determine whether Oxr1 can protect against TDP-43-associated phenotypes in vitro and in vivo, we used the same genetic approach in a newly described transgenic mouse expressing the human TDP-43 locus harbouring an ALS disease mutation (TDP-43M337V). We show in primary motor neurons from TDP-43M337V mice that genetically-driven Oxr1 over-expression significantly alleviates cytoplasmic mislocalization of mutant TDP-43. We also further quantified newly-identified, late-onset neuromuscular phenotypes of this mutant line, and demonstrate that neuronal Oxr1 over-expression causes a significant reduction in muscle denervation and neuromuscular junction degeneration in homozygous mutants in parallel with improved motor function and a reduction in neuroinflammation. Together these data support the application of Oxr1 as a viable and safe modifier of TDP-43-associated ALS phenotypes.

scholarly journals Pathological Roles of Wild-Type Cu, Zn-Superoxide Dismutase in Amyotrophic Lateral Sclerosis

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Yoshiaki Furukawa
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Superoxide Dismutase ◽  
Motor Neurons ◽  
Wild Type ◽  
Sporadic Als ◽  
Familial Form ◽  
Recent Developments ◽  
Lateral Sclerosis

Dominant mutations in a Cu, Zn-superoxide dismutase (SOD1) gene cause a familial form of amyotrophic lateral sclerosis (ALS). While it remains controversial how SOD1 mutations lead to onset and progression of the disease, manyin vitroandin vivostudies have supported a gain-of-toxicity mechanism where pathogenic mutations contribute to destabilizing a native structure of SOD1 and thus facilitate misfolding and aggregation. Indeed, abnormal accumulation of SOD1-positive inclusions in spinal motor neurons is a pathological hallmark in SOD1-related familial ALS. Furthermore, similarities in clinical phenotypes and neuropathology of ALS cases with and without mutations insod1gene have implied a disease mechanism involving SOD1 common to all ALS cases. Although pathogenic roles of wild-type SOD1 in sporadic ALS remain controversial, recent developments of novel SOD1 antibodies have made it possible to characterize wild-type SOD1 under pathological conditions of ALS. Here, I have briefly reviewed recent progress on biochemical and immunohistochemical characterization of wild-type SOD1 in sporadic ALS cases and discussed possible involvement of wild-type SOD1 in a pathomechanism of ALS.

scholarly journals Monocarboxylate Transport in Drosophila Larval Brain during Low and High Neuronal Activity

2019 ◽  
Author(s):  
Andres Gonzalez-Gutierrez ◽  
Andrés Ibacache ◽  
Andrés Esparza ◽  
L. Felipe Barros ◽  
Jimena Sierralta
Keyword(s):  
Glial Cells ◽  
Motor Neurons ◽  
Ex Vivo ◽  
Larval Brain ◽  
Metabolic Coupling ◽  
Monocarboxylate Transport ◽  
Lactate And Pyruvate ◽  
Increased Activity

ABSTRACTThe transport of lactate and pyruvate between glial cells and neurons plays an important role in the nervous system metabolic coupling. However, the mechanisms and characteristics that underlie the transport of monocarboxylates (MC-T) in vivo are poorly described. Here we use Drosophila expressing genetically-encoded FRET sensors to provide an ex vivo characterization of the MC-T in motor neurons and glial cells from the ventral nerve cord. We show that lactate/pyruvate transport on glial cells is coupled to protons and is more efficient than in neurons. Glial cells maintain higher levels of intracellular lactate generating a positive gradient towards neurons. Moreover, our results show that under increased activity lactate and pyruvate rise on motor neurons and suggest that this depends on the transfer of lactate from glial cells mediated in part by the previously described MC transporter Chaski, giving support to the in vivo glia to neurons lactate shuttling during activity.

scholarly journals FUS-ALS mutants alter FMRP phase separation equilibrium and impair protein translation

2021 ◽  
Vol 7 (30) ◽  
pp. eabf8660
Author(s):  
Nicol Birsa ◽  
Agnieszka M. Ule ◽  
Maria Giovanna Garone ◽  
Brian Tsang ◽  
Francesca Mattedi ◽  
...  
Keyword(s):  
Phase Separation ◽  
Motor Neurons ◽  
Rna Binding ◽  
Fragile X ◽  
Protein Translation ◽  
Fused In Sarcoma ◽  
Mental Retardation Protein ◽  
Lateral Sclerosis

FUsed in Sarcoma (FUS) is a multifunctional RNA binding protein (RBP). FUS mutations lead to its cytoplasmic mislocalization and cause the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Here, we use mouse and human models with endogenous ALS-associated mutations to study the early consequences of increased cytoplasmic FUS. We show that in axons, mutant FUS condensates sequester and promote the phase separation of fragile X mental retardation protein (FMRP), another RBP associated with neurodegeneration. This leads to repression of translation in mouse and human FUS-ALS motor neurons and is corroborated in vitro, where FUS and FMRP copartition and repress translation. Last, we show that translation of FMRP-bound RNAs is reduced in vivo in FUS-ALS motor neurons. Our results unravel new pathomechanisms of FUS-ALS and identify a novel paradigm by which mutations in one RBP favor the formation of condensates sequestering other RBPs, affecting crucial biological functions, such as protein translation.

scholarly journals Amyotrophic Lateral Sclerosis and Autophagy: Dysfunction and Therapeutic Targeting

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2413
Author(s):  
Azin Amin ◽  
Nirma D. Perera ◽  
Philip M. Beart ◽  
Bradley J. Turner ◽  
Fazel Shabanpoor
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Protein Aggregates ◽  
Misfolded Proteins ◽  
Protein Aggregate ◽  
In Vivo Models ◽  
Primary Stress ◽  
Lateral Sclerosis

Over the past 20 years, there has been a drastically increased understanding of the genetic basis of Amyotrophic Lateral Sclerosis. Despite the identification of more than 40 different ALS-causing mutations, the accumulation of neurotoxic misfolded proteins, inclusions, and aggregates within motor neurons is the main pathological hallmark in all cases of ALS. These protein aggregates are proposed to disrupt cellular processes and ultimately result in neurodegeneration. One of the main reasons implicated in the accumulation of protein aggregates may be defective autophagy, a highly conserved intracellular “clearance” system delivering misfolded proteins, aggregates, and damaged organelles to lysosomes for degradation. Autophagy is one of the primary stress response mechanisms activated in highly sensitive and specialised neurons following insult to ensure their survival. The upregulation of autophagy through pharmacological autophagy-inducing agents has largely been shown to reduce intracellular protein aggregate levels and disease phenotypes in different in vitro and in vivo models of neurodegenerative diseases. In this review, we explore the intriguing interface between ALS and autophagy, provide a most comprehensive summary of autophagy-targeted drugs that have been examined or are being developed as potential treatments for ALS to date, and discuss potential therapeutic strategies for targeting autophagy in ALS.

scholarly journals Alterations in Tau Metabolism in ALS and ALS-FTSD

2020 ◽  
Vol 11 ◽  
Author(s):  
Michael J. Strong ◽  
Neil S. Donison ◽  
Kathryn Volkening
Keyword(s):  
Motor Neurons ◽  
Chronic Traumatic Encephalopathy ◽  
Dna Binding Protein ◽  
Tau Phosphorylation ◽  
Protein Tau ◽  
Oligomer Formation ◽  
Biological Heterogeneity ◽  
Lateral Sclerosis

There is increasing acceptance that amyotrophic lateral sclerosis (ALS), classically considered a neurodegenerative disease affecting almost exclusively motor neurons, is syndromic with both clinical and biological heterogeneity. This is most evident in its association with a broad range of neuropsychological, behavioral, speech and language deficits [collectively termed ALS frontotemporal spectrum disorder (ALS-FTSD)]. Although the most consistent pathology of ALS and ALS-FTSD is a disturbance in TAR DNA binding protein 43 kDa (TDP-43) metabolism, alterations in microtubule-associated tau protein (tau) metabolism can also be observed in ALS-FTSD, most prominently as pathological phosphorylation at Thr175 (pThr175tau). pThr175 has been shown to promote exposure of the phosphatase activating domain (PAD) in the tau N-terminus with the consequent activation of GSK3β mediated phosphorylation at Thr231 (pThr231tau) leading to pathological oligomer formation. This pathological cascade of tau phosphorylation has been observed in chronic traumatic encephalopathy with ALS (CTE-ALS) and in both in vivo and in vitro experimental paradigms, suggesting that it is of critical relevance to the pathobiology of ALS-FTSD. It is also evident that the co-existence of alterations in the metabolism of TDP-43 and tau acts synergistically in a rodent model to exacerbate the pathology of either.

Sign in / Sign up

Export Citation Format

Share Document