Publicação
Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology
| Resumo: | Despite considerable progress in the understanding of molecular underpinnings of neuronal malfunction and cognitive impairment associated with Alzheimer’s disease (AD), the physiopathology of the disorder is complex and poorly understood. Chronic environmental stress and the major stress hormones, glucocorticoids (GC), are suggested precipitating factors for AD, and have been shown to trigger APP misprocessing and Aβ production as well as Tau hyperphosphorylation, accumulation and downstream neuronal atrophy and malfunction. However, the mechanisms that regulate intraneuronal trafficking and homeostasis of Aβ & Tau remain poorly understood. Given the critical role of Rab GTPases as master regulators of endosomal protein trafficking, these PhD studies have explored the role of Rabs in Aβ & Tau proteostasis and their significance in AD pathogenesis. We found that the levels of a specific Rab, Rab35, are significantly decreased aged animals, as well in animals exposed to high GC levels or chronic stress, known triggers of APP misprocessing. Using a gain-of-function screen of Rabs that regulate endocytic protein trafficking, we showed that Rab35 is the most potent suppressor of the interaction of APP and BACE, the first enzyme involved in APP misprocessing towards the generation of Aβ. On the contrary, reduced Rab35 may promote the APP misprocessing suggesting Rab35 as an important regulator of the intraneuronal cascade that generates Aβ. In another set of studies of this PhD thesis, we demonstrated for the first time that Rab35 also controls degradation of Tau protein into the endolysosomal pathway through the Rab35-driven induction of the endosomal sorting complex required for transport (ESCRT) machinery. We also detected a phospho-dependent selectivity of Tau sorting into the Rab35/ESCRT pathway, while high GC levels suppress Rab35 expression and ESCRT machinery leading to Tau accumulation on both in vitro and in vivo studies. Importantly, AAV-mediated Rab35 expression rescues both GC-induced Tau accumulation and neuronal atrophy in the hippocampus of experimental animals. Altogether, the findings of these PhD studies suggest an essential role for Rab35 in the intraneuronal mechanisms underlying Aβ generation and Tau accumulation in AD as well as their significance to the precipitating role of chronic stress towards brain pathology. As emerging evidence suggest that the involvement of Tau in multiple neuropathological conditions, including Alzheimer’s disease, frontotemporal dementia, chronic stress and epilepsy, identifying the cellular pathways responsible for Tau intra- and extra-cellular trafficking, as well as positive and negative regulators of these pathways, has broad therapeutic relevance. |
|---|---|
| Autores principais: | Silva, João Luís Vaz Lima da |
| Assunto: | Ciências Médicas::Ciências da Saúde |
| Ano: | 2019 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| _version_ | 1867439726924922880 |
|---|---|
| author | Silva, João Luís Vaz Lima da |
| author_facet | Silva, João Luís Vaz Lima da |
| author_role | author |
| contributor_name_str_mv | Sotiropoulos, I. Waites, Clarissa RepositóriUM - Universidade do Minho |
| country_str | PT |
| creators_json_txt | [{\"Person.name\":\"Silva, João Luís Vaz Lima da\"}] |
| datacite.contributors.contributor.contributorName.fl_str_mv | Sotiropoulos, I. Waites, Clarissa RepositóriUM - Universidade do Minho |
| datacite.creators.creator.creatorName.fl_str_mv | Silva, João Luís Vaz Lima da |
| datacite.date.Accepted.fl_str_mv | 2019-04-02T00:00:00Z |
| datacite.date.available.fl_str_mv | 2022-04-02T06:00:30Z |
| datacite.date.embargoed.fl_str_mv | 2022-04-02T06:00:30Z |
| datacite.rights.fl_str_mv | http://purl.org/coar/access_right/c_abf2 |
| datacite.subjects.subject.fl_str_mv | Ciências Médicas::Ciências da Saúde |
| datacite.titles.title.fl_str_mv | Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology |
| dc.contributor.none.fl_str_mv | Sotiropoulos, I. Waites, Clarissa RepositóriUM - Universidade do Minho |
| dc.creator.none.fl_str_mv | Silva, João Luís Vaz Lima da |
| dc.date.Accepted.fl_str_mv | 2019-04-02T00:00:00Z |
| dc.date.available.fl_str_mv | 2022-04-02T06:00:30Z |
| dc.date.embargoed.fl_str_mv | 2022-04-02T06:00:30Z |
| dc.description.none.fl_str_mv | Apesar do progresso considerável na compreensão das bases moleculares do mau funcionamento neuronal e do comprometimento cognitivo associado à doença de Alzheimer (DA), a fisiopatologia da doença é complexa e pouco compreendida. O stress ambiental crónico e as principais hormonas do stress, os glucocorticóides (GC), são sugeridos como factores desencadeantes da DA, e têm mostrado desencadear o mal processamento da APP e a produção de Aβ, bem como a hiperfosforilação e acumulação da Tau, conduzindo a atrofia neuronal. No entanto, os mecanismos que regulam o tráfego intraneuronal e a homeostase de Aβ e Tau permanecem pouco compreendidos. Dado o papel crítico das Rab GTPases como reguladores do tráfico de proteína endossomais, este trabalho de doutoramento explorara o papel das Rabs na proteostase da Aβ e da Tau, assim como a sua importância na patogénese da DA. Descobrimos que os níveis de uma Rab específica, Rab35, estão significativamente diminuídos em animais envelhecidos, assim como em animais expostos a altos níveis de GC ou stress crónico, desencadeadores do processamento amiloidogénico de APP. Usando um ensaio de ganho de função de Rabs, que regulam o tráfego de proteínas endocíticas, mostramos que a Rab35 é o supressor mais potente, entre estas, da interação entre APP e BACE, a primeira enzima envolvida no processamento de APP em Aβ. Pelo contrário, a redução dos níveis de Rab35 pode promover o processamento amiloidogénico de APP, sugerindo que a Rab35 é um importante regulador da cascata intraneuronal que gera Aβ. Noutro conjunto de estudos desta tese de doutoramento, demonstramos pela primeira vez que a Rab35 também é capaz de controlar a degradação da proteína Tau na via endolisossomal através da indução do complexo Endosomal Sorting Complex Required for Transport (ESCRT) pela Rab35. Detectamos também que a selecção para a via Rab35/ESCRT é dependente do estado de fosforilação da Tau, enquanto que altos níveis de GC suprimem a expressão de Rab35, levando à acumulação de Tau in vitro e in vivo. A expressão de Rab35 mediada por AAV é capaz de resgatar tanto a acumulação de Tau induzida por GC, como a atrofia neuronal no hipocampo destes animais. Em conjunto, os resultados apresentados nesta tese de doutoramento, sugerem um papel essencial para Rab35 nos mecanismos intraneuronais subjacentes à geração de Aβ e ao acúmulo de Tau na DA, bem como a sua importância para o efeito do stress na indução de patologia cerebral. Evidências emergentes sugerem que a Tau está envolvida em múltiplos mecanismos neuropatológicas, incluindo a doença de Alzheimer, demência frontotemporal, stress crónico e epilepsia, assim, identificar as vias celulares responsáveis pelo tráfico intra e extra-celular da Tau, bem como os seus reguladores positivos e negativos, tem uma ampla relevância terapêutica. |
| dc.format.none.fl_str_mv | application/pdf |
| dc.identifier.none.fl_str_mv | https://hdl.handle.net/1822/65745 |
| dc.language.none.fl_str_mv | eng |
| dc.rights.none.fl_str_mv | http://purl.org/coar/access_right/c_abf2 |
| dc.subject.none.fl_str_mv | Ciências Médicas::Ciências da Saúde |
| dc.title.fl_str_mv | Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology |
| dc.type.none.fl_str_mv | http://purl.org/coar/resource_type/c_db06 |
| description | Despite considerable progress in the understanding of molecular underpinnings of neuronal malfunction and cognitive impairment associated with Alzheimer’s disease (AD), the physiopathology of the disorder is complex and poorly understood. Chronic environmental stress and the major stress hormones, glucocorticoids (GC), are suggested precipitating factors for AD, and have been shown to trigger APP misprocessing and Aβ production as well as Tau hyperphosphorylation, accumulation and downstream neuronal atrophy and malfunction. However, the mechanisms that regulate intraneuronal trafficking and homeostasis of Aβ & Tau remain poorly understood. Given the critical role of Rab GTPases as master regulators of endosomal protein trafficking, these PhD studies have explored the role of Rabs in Aβ & Tau proteostasis and their significance in AD pathogenesis. We found that the levels of a specific Rab, Rab35, are significantly decreased aged animals, as well in animals exposed to high GC levels or chronic stress, known triggers of APP misprocessing. Using a gain-of-function screen of Rabs that regulate endocytic protein trafficking, we showed that Rab35 is the most potent suppressor of the interaction of APP and BACE, the first enzyme involved in APP misprocessing towards the generation of Aβ. On the contrary, reduced Rab35 may promote the APP misprocessing suggesting Rab35 as an important regulator of the intraneuronal cascade that generates Aβ. In another set of studies of this PhD thesis, we demonstrated for the first time that Rab35 also controls degradation of Tau protein into the endolysosomal pathway through the Rab35-driven induction of the endosomal sorting complex required for transport (ESCRT) machinery. We also detected a phospho-dependent selectivity of Tau sorting into the Rab35/ESCRT pathway, while high GC levels suppress Rab35 expression and ESCRT machinery leading to Tau accumulation on both in vitro and in vivo studies. Importantly, AAV-mediated Rab35 expression rescues both GC-induced Tau accumulation and neuronal atrophy in the hippocampus of experimental animals. Altogether, the findings of these PhD studies suggest an essential role for Rab35 in the intraneuronal mechanisms underlying Aβ generation and Tau accumulation in AD as well as their significance to the precipitating role of chronic stress towards brain pathology. As emerging evidence suggest that the involvement of Tau in multiple neuropathological conditions, including Alzheimer’s disease, frontotemporal dementia, chronic stress and epilepsy, identifying the cellular pathways responsible for Tau intra- and extra-cellular trafficking, as well as positive and negative regulators of these pathways, has broad therapeutic relevance. |
| dirty | 0 |
| eu_rights_str_mv | openAccess |
| format | doctoralThesis |
| fulltext.url.fl_str_mv | https://repositorium.uminho.pt/bitstreams/90124c10-2131-4a38-982c-e10abe2cabdc/download |
| id | rum_5bb4c328bbca7b8daadafa5c76e04c19 |
| identifier.url.fl_str_mv | https://hdl.handle.net/1822/65745 |
| instacron_str | repositorium |
| institution | Universidade do Minho |
| instname_str | Universidade do Minho |
| language | eng |
| network_acronym_str | rum |
| network_name_str | RepositóriUM - Universidade do Minho |
| oai_identifier_str | oai:repositorium.uminho.pt:1822/65745 |
| organization_str_mv | urn:organizationAcronym:repositorium |
| person_str_mv | Silva, João Luís Vaz Lima da |
| publishDate | 2019 |
| reponame_str | RepositóriUM - Universidade do Minho |
| repository_id_str | urn:repositoryAcronym:rum |
| service_str_mv | urn:repositoryAcronym:rum |
| spelling | engengDespite considerable progress in the understanding of molecular underpinnings of neuronal malfunction and cognitive impairment associated with Alzheimer’s disease (AD), the physiopathology of the disorder is complex and poorly understood. Chronic environmental stress and the major stress hormones, glucocorticoids (GC), are suggested precipitating factors for AD, and have been shown to trigger APP misprocessing and Aβ production as well as Tau hyperphosphorylation, accumulation and downstream neuronal atrophy and malfunction. However, the mechanisms that regulate intraneuronal trafficking and homeostasis of Aβ & Tau remain poorly understood. Given the critical role of Rab GTPases as master regulators of endosomal protein trafficking, these PhD studies have explored the role of Rabs in Aβ & Tau proteostasis and their significance in AD pathogenesis. We found that the levels of a specific Rab, Rab35, are significantly decreased aged animals, as well in animals exposed to high GC levels or chronic stress, known triggers of APP misprocessing. Using a gain-of-function screen of Rabs that regulate endocytic protein trafficking, we showed that Rab35 is the most potent suppressor of the interaction of APP and BACE, the first enzyme involved in APP misprocessing towards the generation of Aβ. On the contrary, reduced Rab35 may promote the APP misprocessing suggesting Rab35 as an important regulator of the intraneuronal cascade that generates Aβ. In another set of studies of this PhD thesis, we demonstrated for the first time that Rab35 also controls degradation of Tau protein into the endolysosomal pathway through the Rab35-driven induction of the endosomal sorting complex required for transport (ESCRT) machinery. We also detected a phospho-dependent selectivity of Tau sorting into the Rab35/ESCRT pathway, while high GC levels suppress Rab35 expression and ESCRT machinery leading to Tau accumulation on both in vitro and in vivo studies. Importantly, AAV-mediated Rab35 expression rescues both GC-induced Tau accumulation and neuronal atrophy in the hippocampus of experimental animals. Altogether, the findings of these PhD studies suggest an essential role for Rab35 in the intraneuronal mechanisms underlying Aβ generation and Tau accumulation in AD as well as their significance to the precipitating role of chronic stress towards brain pathology. As emerging evidence suggest that the involvement of Tau in multiple neuropathological conditions, including Alzheimer’s disease, frontotemporal dementia, chronic stress and epilepsy, identifying the cellular pathways responsible for Tau intra- and extra-cellular trafficking, as well as positive and negative regulators of these pathways, has broad therapeutic relevance.porApesar do progresso considerável na compreensão das bases moleculares do mau funcionamento neuronal e do comprometimento cognitivo associado à doença de Alzheimer (DA), a fisiopatologia da doença é complexa e pouco compreendida. O stress ambiental crónico e as principais hormonas do stress, os glucocorticóides (GC), são sugeridos como factores desencadeantes da DA, e têm mostrado desencadear o mal processamento da APP e a produção de Aβ, bem como a hiperfosforilação e acumulação da Tau, conduzindo a atrofia neuronal. No entanto, os mecanismos que regulam o tráfego intraneuronal e a homeostase de Aβ e Tau permanecem pouco compreendidos. Dado o papel crítico das Rab GTPases como reguladores do tráfico de proteína endossomais, este trabalho de doutoramento explorara o papel das Rabs na proteostase da Aβ e da Tau, assim como a sua importância na patogénese da DA. Descobrimos que os níveis de uma Rab específica, Rab35, estão significativamente diminuídos em animais envelhecidos, assim como em animais expostos a altos níveis de GC ou stress crónico, desencadeadores do processamento amiloidogénico de APP. Usando um ensaio de ganho de função de Rabs, que regulam o tráfego de proteínas endocíticas, mostramos que a Rab35 é o supressor mais potente, entre estas, da interação entre APP e BACE, a primeira enzima envolvida no processamento de APP em Aβ. Pelo contrário, a redução dos níveis de Rab35 pode promover o processamento amiloidogénico de APP, sugerindo que a Rab35 é um importante regulador da cascata intraneuronal que gera Aβ. Noutro conjunto de estudos desta tese de doutoramento, demonstramos pela primeira vez que a Rab35 também é capaz de controlar a degradação da proteína Tau na via endolisossomal através da indução do complexo Endosomal Sorting Complex Required for Transport (ESCRT) pela Rab35. Detectamos também que a selecção para a via Rab35/ESCRT é dependente do estado de fosforilação da Tau, enquanto que altos níveis de GC suprimem a expressão de Rab35, levando à acumulação de Tau in vitro e in vivo. A expressão de Rab35 mediada por AAV é capaz de resgatar tanto a acumulação de Tau induzida por GC, como a atrofia neuronal no hipocampo destes animais. Em conjunto, os resultados apresentados nesta tese de doutoramento, sugerem um papel essencial para Rab35 nos mecanismos intraneuronais subjacentes à geração de Aβ e ao acúmulo de Tau na DA, bem como a sua importância para o efeito do stress na indução de patologia cerebral. Evidências emergentes sugerem que a Tau está envolvida em múltiplos mecanismos neuropatológicas, incluindo a doença de Alzheimer, demência frontotemporal, stress crónico e epilepsia, assim, identificar as vias celulares responsáveis pelo tráfico intra e extra-celular da Tau, bem como os seus reguladores positivos e negativos, tem uma ampla relevância terapêutica.application/pdfporUnraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathologySilva, João Luís Vaz Lima daSotiropoulos, I.Waites, ClarissaHostingInstitutionOrganizationalRepositóriUM - Universidade do Minhoe-mailmailto:repositorium@usdb.uminho.ptrepositorium@usdb.uminho.pt2022-04-02T06:00:30Z2019-04-022018-02-162019-04-02T00:00:00ZHandlehttps://hdl.handle.net/1822/65745http://purl.org/coar/access_right/c_abf2open accesshttp://www.oecd.org/science/inno/38235147.pdfFields of Science and Technology (FOS)Ciências Médicas::Ciências da Saúde17955670 bytesliteraturehttp://purl.org/coar/resource_type/c_db06doctoral thesishttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorium.uminho.pt/bitstreams/90124c10-2131-4a38-982c-e10abe2cabdc/download |
| spellingShingle | Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology Silva, João Luís Vaz Lima da Ciências Médicas::Ciências da Saúde |
| status | SINGLETON |
| subject.other.fl_str_mv | Ciências Médicas::Ciências da Saúde |
| title | Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology |
| title_full | Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology |
| title_fullStr | Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology |
| title_full_unstemmed | Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology |
| title_short | Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology |
| title_sort | Unraveling the synaptic role of Rab35: implications for Alzheimer’s disease pathology |
| topic | Ciências Médicas::Ciências da Saúde |
| topic_facet | Ciências Médicas::Ciências da Saúde |
| url | https://hdl.handle.net/1822/65745 |
| visible | 1 |