Tipo
Documentos Académicos
Tipo de Documento
Tese de Doutoramento
Título
S100 proteins as novel modifiers of proteostasis in pathophysiological states
Participantes na publicação
Mariana Amoroso das Neves Romão (Author)
Cláudio Emanuel Moreira Gomes (Supervisor)
Dep. Química e Bioquímica
Dep. Química e Bioquímica
BioISI
Frederic Rousseau (Co-Supervisor)
Katholieke Universiteit Leuven
Resumo
Alzheimer’s disease (AD) is the most prominent cause of dementia and is accompanied by chronic neuroinflammation, protein aggregation and formation of amyloids. During inflammation important modulators of inflammatory responses are implicated, including cytokines and chemokines, among which are S100 proteins. Expression levels of S100 proteins are increased in inflammatory diseases and neurodegenerative disorders such as AD, where they are found around amyloid plaques. This was suggestive of a functional link with Aβ aggregation, in agreement with the newly uncovered activity of S100B as a chaperone suppressor of amyloid formation. This PhD thesis aimed at investigating the role and S100 proteins as potential modifiers of proteostasis in pathophysiological states, resorting to different model systems - from brains of animal models to isolated proteins and peptides, combining cellular, molecular, biophysical, and biochemical techniques. First the distribution of S100 proteins in the brains of AD APP23 mice models was investigated. Results showed that in the brain of wild type mice, S100A6 and S100B are mostly expressed in astrocytes, while low expression of S100A8 was found in neurons and glial cells in vitro. Analysis of APP23 mice brains revealed increased expression of S100A8 in neurons and co-localization of S100 proteins with Aβ plaques. In vitro assays showed that S100A6, S100A8, S100A9, S100A8/A9, delay Aβ aggregation, similarly to S100B. This regulatory activity is similar to that of molecular chaperones, which highlights the potential of S100 proteins as regulators of proteostasis in pathophysiological states. Next, the focus was on the S100A9 protein which is abundant in the brain and has been linked with amyloid formation and deposition in neurodegenerative disorders. We investigated the self-assembly of the S100A9 protein and characterized the formation of polymeric structures formed by this protein, combining biophysical spectroscopies and biochemical assays, outlining the steps of a possible mechanism of functional assembly of this protein with relevance in health and disease.
Data de Publicação
2022-10
Instituição
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA
Identificadores da Publicação
Identificadores do Documento
URL -
http://hdl.handle.net/10451/55590
Keywords
Agregação e Enrolamento de Proteínas Biofísica de Proteínas Doença de Alzheimer Proteínas que ligam Cálcio Chaperões Moleculares Protein Folding and aggregation Protein Biophysics Alzheimer’s disease Calcium proteins Molecular Chaperones
Anotações
Tese de doutoramento, Biologia (Biologia de Sistemas), Universidade de Lisboa, Faculdade de Ciências, 2022