Rilmenidine promotes MTOR-independent autophagy in the mutant SOD1 mouse model of amyotrophic lateral sclerosis without slowing disease progression
| Autor: | Malcolm K. Horne, Philip M Beart, Nirma D Perera, Yea Seul Shin, Chew L. Lau, Rebecca K. Sheean, Bradley J. Turner |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Autophagosome autophagy SOD1 Mice Transgenic Biology Rilmenidine Neuroprotection 03 medical and health sciences Chaperone-mediated autophagy Superoxide Dismutase-1 Mitophagy medicine Animals Humans motor neuron Molecular Biology TARDBP Motor Neurons TOR Serine-Threonine Kinases Neurodegeneration Autophagy Amyotrophic Lateral Sclerosis Research Papers - Basic Science Cell Biology medicine.disease 3. Good health Cell biology DNA-Binding Proteins Disease Models Animal 030104 developmental biology ALS medicine.drug |
| Zdroj: | Autophagy |
| ISSN: | 1554-8635 1554-8627 |
| Popis: | Macroautophagy/autophagy is the main intracellular catabolic pathway in neurons that eliminates misfolded proteins, aggregates and damaged organelles associated with ageing and neurodegeneration. Autophagy is regulated by both MTOR-dependent and -independent pathways. There is increasing evidence that autophagy is compromised in neurodegenerative disorders, which may contribute to cytoplasmic sequestration of aggregation-prone and toxic proteins in neurons. Genetic or pharmacological modulation of autophagy to promote clearance of misfolded proteins may be a promising therapeutic avenue for these disorders. Here, we demonstrate robust autophagy induction in motor neuronal cells expressing SOD1 or TARDBP/TDP-43 mutants linked to amyotrophic lateral sclerosis (ALS). Treatment of these cells with rilmenidine, an anti-hypertensive agent and imidazoline-1 receptor agonist that induces autophagy, promoted autophagic clearance of mutant SOD1 and efficient mitophagy. Rilmenidine administration to mutant SOD1G93A mice upregulated autophagy and mitophagy in spinal cord, leading to reduced soluble mutant SOD1 levels. Importantly, rilmenidine increased autophagosome abundance in motor neurons of SOD1G93A mice, suggesting a direct action on target cells. Despite robust induction of autophagy in vivo, rilmenidine worsened motor neuron degeneration and symptom progression in SOD1G93A mice. These effects were associated with increased accumulation and aggregation of insoluble and misfolded SOD1 species outside the autophagy pathway, and severe mitochondrial depletion in motor neurons of rilmenidine-treated mice. These findings suggest that rilmenidine treatment may drive disease progression and neurodegeneration in this mouse model due to excessive mitophagy, implying that alternative strategies to beneficially stimulate autophagy are warranted in ALS. |
| Databáze: | OpenAIRE |
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