Stefana, I. M. | bioRxiv Science

bioRxiv2026

Expression of non-neuronal Tau in humans and mice

BackgroundTau, encoded by the microtubule-associated protein tau gene (MAPT), is traditionally associated with neuronal function in maintaining cytoskeletal stability and regulating intracellular transport. Its dysregulation is implicated in a range of neurodegenerative disorders. Beyond its well-established high levels of expression in neurons of the central and peripheral nervous systems, increasing evidence indicates that Tau is also expressed in non-neuronal cells/tissues such as muscle, kidney, testis, and pancreas, albeit at much lower levels than in neurons. However, the assessment of low levels of non-neuronal Tau requires that the specificities of the anti-Tau antibodies used are fully validated. MethodsThree previously validated anti-Tau antibodies (Tau-12, Tau-1, RD3) were used to test Tau expression levels in 33 mouse and 66 human tissues using Food and Drug Administration-quality tissue microarrays in immunocytochemistry and western blot analyses. ResultsThe presence of Tau was confirmed in salivary gland, kidney, skeletal muscle, heart, pancreas and oesophagus in both human and mouse tissues. ConclusionsDysregulation of Tau protein expression and alterations in its post-translational modification is a causative factor in neurodegenerative disease. We have demonstrated a wider Tau expression in other tissues and cells, outside the brain, which may be dysregulated in other diseases.

cell biology↗

bioRxiv2023

Validation of Tau Antibodies for Use in Western Blotting and Immunohistochemistry

BackgroundThe microtubule-associated protein Tau has attracted diverse and increasing research interest, with Tau being mentioned in the title/abstract of nearly 34,000 PubMed-indexed publications to date. To accelerate studies into Tau biology, the characterisation of its multiple proteoforms, including disease-relevant post-translational modifications (PTMs), and its role in neurodegeneration, a multitude of Tau-targeting antibodies have been developed, with hundreds of distinct antibody clones currently available for purchase. Nonetheless, concerns over antibody specificity and limited understanding of the performance of many of these reagents has hindered research. MethodsWe have employed a range of techniques in combination with samples of murine and human origin to characterise the performance and specificity of 53 commercially-available Tau antibodies by Western blot, and a subset of these, 35 antibodies, in immunohistochemistry. ResultsContinued expression of residual protein was found in presumptive Tau "knockout" human cells and further confirmed through mass-spectrometry proteomics, providing evidence of Tau isoforms generated by exon skipping. Importantly, many total and isoform-specific antibodies failed to detect this residual Tau, as well as Tau expressed at low, endogenous levels, thus highlighting the importance of antibody choice. Our data further reveal that the binding of several "total" Tau antibodies, which are assumed to detect Tau independently of post-translational modifications, was partially inhibited by phosphorylation. Many antibodies also displayed non-specific cross-reactivity, with some total and phospho-Tau antibodies cross-reacting with MAP2 isoforms, while the "oligomer-specific" T22 antibody detected monomeric Tau on Western blot. Regardless of their specificity, with one exception, the phospho-Tau antibodies tested were found to not detect the unphosphorylated protein. ConclusionsWe identify Tau antibodies across all categories (total, PTM-dependent and isoform-specific) that can be employed in Western blot and/or immunohistochemistry applications to reliably detect even low levels of Tau expression with high specificity. This is of particular importance for studying Tau in non-neuronal cells and peripheral tissues, as well as for the confident validation of knockout cells and/or animal models. This work represents an extensive resource that serves as a point of reference for future studies. Our findings may also aid in the re-interpretation of existing data and improve reproducibility of Tau research.

neuroscience↗