Poster N5 - Design of Synthetic Peptides for Tau-Targeted Vaccination Against Neurodegenerative Diseases

Introduction: The microtubule protein Tau is associated with numerous neurodegenerative diseases, termed tauopathies. In tauopathies, Tau misfolds, forms amyloid fibrils, and deposits itself in neurons. Tauopathies, along with neurodegenerative diseases, have limited treatment options. Currently, there are no vaccines or cures available for any neurodegenerative disease, and only one FDA-approved monoclonal antibody. Due to this, there is urgent need for a vaccine. With neurodegeneration, traditional vaccines have two major problems. One is autoimmunity, where the immune system may target its own healthy proteins. The other problem is the pro-inflammatory response, a typical immune response that can damage the fragile tissue in the brain. A solution to these problems is to use a synthetic, self-assembling peptide that an assemble into nanofibers. Synthetic, self-assembling peptides can elicit a non-inflammatory immune response to any conjugated antigen and present conformational epitope (Panel A). Through conjugated tau to the synthetic peptide KFE8, we can design a vaccine to target tauopathies.

Materials and

Methods: KFE8 was produced using a chemical synthesizer. The sequence of KFE8 was cloned into a tau plasmid to create the two conjugates: KFE8-Tau and Tau-KFE8. Tau and the conjugates were expressed and purified from E. coli cells. Aggregation of the proteins were tested with Thioflavin-T. The proteins were rocked at 37°C, 1500rpm for 1 week, with a Thioflavin-T reading each day. The resulting fibrils were imaged with TEM and used in a seeding assay. HEK293T FRET biosensor cells expressing tau were utilized. The fibrils were added to the cells, and two days later, the cells were observed to determine if foci formed. The cells were run through a flow cytometer to quantitate the FRET signal.

Results, Conclusions, and Discussions: We successfully were able to produce purified tau and tau conjugates. During the aggregation assay, KFE8-Tau activity was half of Tau, and there was no aggregation assay of Tau-KFE8 (Panel B). This was confirmed with TEM. KFE8-Tau fibrils appeared similar to Tau, while Tau-KFE8 did not form fibrils. For the seeding assay, both extraneous Tau and KFE8-Tau induced aggregation of native Tau. Tau-KFE8, however, did not induce aggregation of native Tau (Panel C). This was verified by both microscopy and flow cytometry. This is promising data for a new platform for vaccination. This is also interesting data, in that the C-term KFE8 tag construct does not aggregate, but the N-term KFE8 tag construct does.

Acknowledgements (Optional):