Single copy/knock-in models of ALS SOD1 in C. elegans suggest loss and gain of function have different contributions to cholinergic and glutamatergic neurodegeneration
| Autor: | Jill M. Yersak, Patrick J O'Hern, Anne C. Hart, Maria Dimitriadi, Sarah Grosser, Kelsey N. Schuch, Saba N. Baskoylu, Sarah Kim, Katherine S. Yanagi, Jonah Simon, Jeremy Lins |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Cancer Research Nematoda Physiology QH426-470 Biochemistry Animals Genetically Modified Motor Neuron Diseases Superoxide Dismutase-1 0302 clinical medicine Gene Frequency Loss of Function Mutation Animal Cells Medicine and Health Sciences Gene Knock-In Techniques Amyotrophic lateral sclerosis Genetics (clinical) Motor Neurons Neurons Neurodegeneration Eukaryota Neurochemistry Neurodegenerative Diseases Animal Models Neurotransmitters Cholinergic Neurons Enzymes Cell biology Dismutases medicine.anatomical_structure Experimental Organism Systems Neurology Caenorhabditis Elegans Gain of Function Mutation Cellular Types Research Article Cholinergics SOD1 Glutamic Acid Biology Research and Analysis Methods 03 medical and health sciences Glutamatergic Model Organisms Gene knockin Genetics medicine Animals Humans Amino Acid Sequence Caenorhabditis elegans Proteins Molecular Biology Ecology Evolution Behavior and Systematics Loss function Base Sequence Superoxide Dismutase Biological Locomotion Amyotrophic Lateral Sclerosis Organisms Biology and Life Sciences Proteins nutritional and metabolic diseases Cell Biology medicine.disease Invertebrates Disease Models Animal Oxidative Stress 030104 developmental biology nervous system Cellular Neuroscience Animal Studies Caenorhabditis Enzymology Cholinergic Neuron CRISPR-Cas Systems 030217 neurology & neurosurgery Neuroscience |
| Zdroj: | PLoS Genetics PLoS Genetics, Vol 14, Iss 10, p e1007682 (2018) |
| ISSN: | 1553-7404 |
| Popis: | Mutations in Cu/Zn superoxide dismutase 1 (SOD1) lead to Amyotrophic Lateral Sclerosis (ALS), a neurodegenerative disease that disproportionately affects glutamatergic and cholinergic motor neurons. Previous work with SOD1 overexpression models supports a role for SOD1 toxic gain of function in ALS pathogenesis. However, the impact of SOD1 loss of function in ALS cannot be directly examined in overexpression models. In addition, overexpression may obscure the contribution of SOD1 loss of function in the degeneration of different neuronal populations. Here, we report the first single-copy, ALS knock-in models in C. elegans generated by transposon- or CRISPR/Cas9- mediated genome editing of the endogenous sod-1 gene. Introduction of ALS patient amino acid changes A4V, H71Y, L84V, G85R or G93A into the C. elegans sod-1 gene yielded single-copy/knock-in ALS SOD1 models. These differ from previously reported overexpression models in multiple assays. In single-copy/knock-in models, we observed differential impact of sod-1 ALS alleles on glutamatergic and cholinergic neurodegeneration. A4V, H71Y, G85R, and G93A animals showed increased SOD1 protein accumulation and oxidative stress induced degeneration, consistent with a toxic gain of function in cholinergic motor neurons. By contrast, H71Y, L84V, and G85R lead to glutamatergic neuron degeneration due to sod-1 loss of function after oxidative stress. However, dopaminergic and serotonergic neuronal populations were spared in single-copy ALS models, suggesting a neuronal-subtype specificity previously not reported in invertebrate ALS SOD1 models. Combined, these results suggest that knock-in models may reproduce the neurotransmitter-type specificity of ALS and that both SOD1 loss and gain of toxic function differentially contribute to ALS pathogenesis in different neuronal populations. Author summary In all SOD1 ALS patients, cholinergic spinal motor neurons degenerate, but degeneration of cortical glutamatergic neurons is less common. Despite decades of work, it remains unclear why some disease alleles (e.g. A4V) primarily affect cholinergic spinal neurons, while other alleles affect both cholinergic and glutamatergic neurons. New genome editing techniques allowed us to create the first C. elegans knock-in/single-copy models for SOD1 ALS by directly editing the C. elegans sod-1 gene to recreate SOD1 amino acid changes that cause ALS in patients. These new models are complementary to previously described overexpression models, which revealed mutant SOD1 toxic gain of function properties. By contrast, in the new C. elegans knock-in models, we find that both loss and gain of sod-1 function contribute to neurodegeneration. C. elegans cholinergic motor neuron loss is primarily driven by toxic gain of function, but glutamatergic neuron loss is primarily driven by loss of function. Only cholinergic and glutamatergic neurons degenerate in C. elegans knock-in models; dopaminergic, serotoninergic and GABAergic neurons do not. This pattern of neuronal loss is reminiscent of the pattern of neuronal loss seen in SOD1 ALS patients. Strikingly, in the C. elegans A4V model, only cholinergic neurons are lost. Our results suggest that an underlying premise of the ALS field–that identical pathological mechanisms lead to degeneration of cholinergic and glutamatergic neurons–should be reconsidered. Mechanisms that predominantly drive glutamatergic and cholinergic neuron degeneration in ALS may not be identical. |
| Databáze: | OpenAIRE |
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