Affordable Access

Identification of the modulators of and the molecular pathways involved in the BIN1-Tau interaction

Authors
  • Mendes, Tiago
Publication Date
Dec 13, 2018
Source
HAL
Keywords
Language
English
License
Unknown
External links

Abstract

The main neuropathological hallmarks of Alzheimer’s disease (AD) are the extracellular senile plaques composed of amyloid-β peptide (Aβ) and the intracellular neurofibrillary tangles composed of hyperphosphorylated Tau. The mechanisms leading to the formation of these lesions is not well understood and our lab has recently characterized the bridging integrator 1 (BIN1) gene, the second most associated genetic risk factor of AD and the first genetic risk factor to have a potential link to Tau pathology. The interaction between BIN1 and Tau proteins has been described in vitro and in vivo, which suggests that BIN1 might help us to understand Tau pathology in the context of AD. However, the role of BIN1-Tau interaction in the pathophysiological process of AD is not known, and whether this interaction is a potential therapeutic target remains to be determined. The aim of this project is to better understand the actors of BIN1-Tau interaction through the identification of the modulators and the molecular pathways involved therein, as well as to understand how BIN1-Tau interaction is modulated in the context of AD. We employed biochemistry, nuclear magnetic resonance, and confocal microscopy. We used rat primary neuronal cultures (PNC) as the cellular model and developed the proximity ligation assay (PLA) as the main readout of the BIN1-Tau interaction in cultured neurons. We determined that the interaction occurs between BIN1’s SH3 domain and Tau’s PRD domain, and demonstrated that it is modulated by Tau and BIN1 phosphorylation: phosphorylation of Tau at Threonine 231 decreases its interaction with BIN1, while phosphorylation of BIN1 at Threonine 348 (T348) increases its interaction with Tau. We developed a novel, semi-automated high content screening (HCS) assay based on a commercial compound library, also using PNC as the cellular model and PLA as the readout of BIN1-Tau interaction. We identified several compounds that are able to modulate the BIN1-Tau interaction, most notably U0126, an inhibitor of MEK-1/2, which reduced the interaction, and Cyclosporin A, an inhibitor of Calcineurin, which increased the interaction through increasing the BIN1 phosphorylation at T348. Furthermore, Cyclin-dependent kinases (CDK) were also shown as regulator of this phosphorylation site. These results suggest that the couple Calcineurin/CDK regulates BIN1 phosphorylation at T348 and consequently the BIN1-Tau interaction. We also developed a mouse model of tauopathy in which we overexpressed human BIN1. We observed that the overexpression of BIN1 rescued the long-term memory deficits and reduced the presence of intracellular inclusions of phosphorylated Tau, caused by Tau overexpression, and this was associated with an increase of BIN1-Tau interaction. Also, using post-mortem human brain samples, we observed that the levels of the neuronal BIN1 isoform were decreased in AD brains, whereas the relative levels of BIN1 phosphorylated at T348 were increased, suggesting a compensatory mechanism. Altogether, this study demonstrated the complexity and the dynamics of BIN1-Tau interaction in neurons, revealed modulators of and molecular pathways potentially involved in this interaction, and showed that variations in BIN1 expression or activity have direct effects on learning and memory, possibly linked to the regulation of its interaction with Tau.

Report this publication

Statistics

Seen <100 times