A carregar...
Publicação
Single-Domain Antibodies targeting S100B as tools in Alzheimer´s disease
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 9.05 MB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the aggregation of the amyloid-β (Aβ) peptide and tau protein. The accumulation of these pathological aggregates in the aged brain promotes neuroinflammation responsible for the secretion of pro-inflammatory mediators, which include the S100B protein. S100B is a multifunctional protein that operates as an aggravating pro inflammatory cytokine or as a protective anti-aggregation chaperone, depending on its concentration. These characteristics make S100B an amenable drug target and the host laboratory developed a library of 28 single-domain antibodies targeting this protein, to generate molecular tools to regulate S100B functions, that might later translate into biologics with therapeutic potential. Indeed, single-domain antibodies (or nanobodies), which are the smallest antigen-binding domain of camelid’s heavy-chain antibodies, have unique properties that favours their applications in biomedicine. This work aimed at characterizing a set of 13 anti-S100B nanobodies, by assessing their interactions with S100B, and by studying their modulatory effect over the aggregation of Aβ and tau, which are implicated in AD. Structural analysis showed that nanobodies have the typical β-sheet immunoglobulin fold and are conformationally stable, with melting temperatures above 65 °C. Interaction assays revealed that several nanobodies formed high-affinity complexes with S100B and were immunoreactive against dimeric and tetrameric forms of S100B. We also used chemical kinetics to test if nanobodies might potentiate the inhibitory effect of S100B over the aggregation of Aβ42 and K18 (tau 244-372 fragment). Indeed, we identified several nanobodies that, in combination with S100B, delay the aggregation and/or decrease formed fibrils. Surprisingly, control experiments revealed that some nanobodies alone significantly inhibit the aggregation of Aβ42 and K18, even at sub-stoichiometric ratios. These observations are discussed in the context of possible heterotypic interactions established between nanobodies and the aggregation-prone proteins. Overall, these findings uncover the therapeutic potential of anti-S100B nanobodies, which can be either used as modulators of the aggregation of AD-related proteins, or as activators of S100B chaperone activity.
Descrição
Tese de mestrado, Bioquímica (Bioquímica Médica) Universidade de Lisboa, Faculdade de Ciências, 2022
Palavras-chave
Doença de Alzheimer Agregação proteica Proteína S100B Anticorpos de domínio único Teses de mestrado - 2022