Characterization of the role of the CPEB family of RNA-binding proteins in neurodegeneration
Alzheimer’s disease (AD) is the most common type of dementia in the elderly. It is associated to a progressive loss of memory, problems in learning and behaviour changes. This disease is characterized by the accumulation of extracellular amyloid β (Aβ) aggregates and intracellular deposits of hyperp...
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| Format: | doctoral thesis |
| Status: | Published version |
| Publication Date: | 2016 |
| Country: | España |
| Institution: | CBUC, CESCA |
| Repository: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/664116 |
| Online Access: | http://hdl.handle.net/10803/664116 |
| Access Level: | Open access |
| Keyword: | Amyloid beta TPA CPEB Translational control Synaptic mRNA cleavage and polyadenylation Beta amiloide Control traducional Corte y poliadenilación sinápticos de ARNm 616.8 |
| Summary: | Alzheimer’s disease (AD) is the most common type of dementia in the elderly. It is associated to a progressive loss of memory, problems in learning and behaviour changes. This disease is characterized by the accumulation of extracellular amyloid β (Aβ) aggregates and intracellular deposits of hyperphosphorylated Tau protein. Both aggregates trigger neuronal apoptosis and glial inflammation, leading to the cognitive decline found in AD patients. Interestingly, the serine protease tissue plasminogen activator (tPA), which is induced by Aβ, has been found to play a dual, dose-dependent role in the disease. Physiological levels of tPA confers neuroprotection through plasmin generation and Aβ degradation. In contrast, high doses of tPA activate intracellular signalling pathways in neurons and glial cells, inducing neuronal apoptosis and inflammation. However, the molecular mechanisms that govern the regulation of tPA expression in AD have still not been fully elucidated. In this work, we demonstrate that Aβ-induced tPA expression is regulated by translational control. In particular, our results show that CPEB1 and CPEB4, two members of the cytoplasmic polyadenylation element binding protein (CPEB) family of RNA-binding proteins, control local tPA synthesis in response to Aβ. Specifically, Aβ promotes tPA mRNA translation in the dendritic spines through synaptic polyadenylation and synaptic cleavage and polyadenylation, a mechanism that is impaired in the absence of CPEB1 or CPEB4. Our results also demonstrate that the pre-mRNA 3'-end processing machinery required for the efficient cleavage and polyadenylation of mRNAs is also present in the synaptic terminals. Finally, we have found that, similarly to tPA, CPEB4 is upregulated in the synaptic terminals in response Aβ and in vivo in the brain of AD patients. |
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