Tau Clearance Assay

Background of Tau Clearance

Microtubule-associated protein tau participates in several biological processes, including microtubule stabilization and assembly, exporting iron, maintaining neuronal cytoskeleton, and axonal transportation. The aggregation of tau in form of neurofibrillary tangles is a hallmark of neurodegenerative Alzheimer's disease (AD). Some post-translational modifications of tau, including phosphorylation, truncation, acetylation, and nitration, are the causes of pathological tau. The accumulation of pathological tau may extend throughout the cortex by tau uptake and seeding among neurons. It has been demonstrated that tau is degraded by both proteasome and autophagy systems. Impairment of the proteasome or the autophagosome results in the aggregations of pathological tau, autophagic vacuoles, and cytosolic p62, which leads to further proteolytic processing and tau accumulation. In addition, antibody-mediated tau phagocytosis by microglia can clear the tau aggregation via a proteasomal pathway. Clearance of the soluble extracellular tau responsible for spreading may positively influence the clinical progression of AD. Consequently, reliable in vitro tau clearance assay services provided by Creative Biolabs enable researchers to establish models for the determination of tau clearance pathways and corresponding tau proteases or antibodies.

Fig.1 Alzheimer's disease-related disruption of tau degradation. (Chesser, et al., 2013)

Tau Clearance Assay at Creative Biolabs

Tau clearance in vitro assay is established with stable cell culture to evaluate the tau aggregation under the treatment of antibodies or proteases. Creative Biolabs provides primary neuronal cell culture models as well as human-induced pluripotent stem cells (iPSC)-derived neuronal cell culture models to imitate the tau clearance process. Our tau clearance assay services are suitable for quantitative studies, which have minimal experimental variability. The workflow of our tau clearance assay service includes the following steps. First, label both tau aggregates and recombinant tau aggregates with pH-sensitive fluorescent dye. Then, read out the results of tau uptake and seeding with both microscope and fluorescence-activated cell sorting. Followed by the readouts of the immunocomplex or enzyme-treated samples. Compare both analytical results so that we can assess the clearance efficacy.

Clearance Assay Service for Tau Isoforms

The Tau clearance assay offered by Creative Biolabs enables the detection of the clearance of tau isoforms. According to the distinct mRNA splicing mechanisms, tau isoforms are classified into the following six types, 0N, 1N, 2N, 1R, 2R, 3R, and 4R tau isoforms. The lopsided ratio of 4R to 3R tau isoforms in the brain, either due to the alteration of 4R or 3R, will cause Alzheimer's tauopathy.

Proteasome and autophagy pathways of tau aggregation have been well explained by previous studies (Chesser, 2013). Understanding detailed mechanisms of tau clearance is a prospective way of novel drug development. Creative Biolabs offers reliable in vitro clearance assays that enable researchers to evaluate the degree of tau clearance compared to pathological tau aggregation. If you want to learn more details about tau clearance in vitro assays, please don't hesitate to contact us.

Reference

1. Chesser, A.; et al. Tau clearance mechanisms and their possible role in the pathogenesis of Alzheimer's disease. Frontiers in neurology. 2013, 4: 122.