Taylor, M. F. | Search bioRxiv

bioRxiv2022

Insights into H2O2-induced signaling in Jurkat cells from analysis of gene expression

Hydrogen peroxide (H2O2) is a ubiquitous oxidant produced in a regulated manner by various enzymes in mammalian cells. H2O2 reversibly oxidises thiol groups of cysteine residues to mediate intracellular signalling. Whilst examples of H2O2 dependent signalling have been reported, the exact molecular mechanism(s) of signalling and the pathways affected are not well understood. Here, the transcriptomic response of Jurkat T cells to H2O2 was investigated to determine global effects on gene expression. With a low H2O2 concentration (10 M) that did not induced an oxidative stress response or cell death, extensive changes in gene expression occurred after 4 hours (6803 differentially expressed genes). Of the genes with greater then 2-fold change in expression, 85% were upregulated suggesting that in a physiological setting H2O2 predominantly activates gene expression. Pathway analysis identified gene expression signatures associated with FOXO and NTRK signalling. These signatures were associated with an overlapping set of transcriptional regulators. Overall, our results provide a snapshot of gene expression changes in response to H2O2, which, along with further studies, will lead to new insights into the specific pathways that are activated in response to endogenous production of H2O2, and the molecular mechanisms of H2O2 signalling.

cell biology↗

bioRxiv2019

Loss of the Alzheimer’s-linked bridging integrator 1 (BIN1) protein affects synaptic structure and disrupts tau localisation and release

BackgroundPost-translational modifications of tau modify its interaction with binding partners and cause tau mislocalisation and altered tau function in Alzheimers disease (AD). The AD risk gene BIN1, is a binding partner for tau, however the mechanism by which BIN1 influences tau function is not fully understood. We hypothesised that BIN1 modulates AD risk by causing damaging tau mis-sorting to the synapse.\n\nMethodsTau and BIN1 levels, distribution and interactions were assessed in post-mortem control and AD brain and in primary neurons. In primary neurons, tau was further examined using structured illumination microscopy and immunoblotting following BIN1 knockdown, BIN1-tau interactions were examined using proximity ligation assays and tau release from neurons was measured by sensitive sandwich ELISA.\n\nResultsProline 216 in tau was identified as critical for tau interaction with the BIN1-SH3 domain, and tau phosphorylation at serine/threonine residues disrupted this interaction. Subcellular fractionation showed that BIN1 is lost from the cytoplasm of AD brain and this correlated with the mislocalisation of phosphorylated tau to synapses. Mimicking BIN1 loss in AD by knockdown of the protein in primary neurons altered the structure of dendritic spines, caused phosphorylated tau to mis-sort to synapses and reduced the physiological release of predominantly dephosphorylated tau.\n\nConclusionsThese data suggest that BIN1 loss in AD allows phosphorylated tau to be mis-sorted to synapses which likely alters the integrity of the post-synapse, alongside reducing the functionally important release of physiological forms of tau.

neuroscience↗