α-Synuclein modulates tau spreading in mouse brains
Fares Bassil, Emily S. Meymand, Hannah J. Brown, Hong Xu, Timothy Cox, Shankar Pattabhiraman, Chantal Maghames, Qihui Wu, Bin Zhang, John Q. Trojanowski, Virginia M.‐Y. Lee
Abstract
α-Synuclein (α-syn) and tau aggregates are the neuropathological hallmarks of Parkinson's disease (PD) and Alzheimer's disease (AD), respectively, although both pathologies co-occur in patients with these diseases, suggesting possible crosstalk between them. To elucidate the interactions of pathological α-syn and tau, we sought to model these interactions. We show that increased accumulation of tau aggregates occur following simultaneous introduction of α-syn mousepreformed fibrils (mpffs) and AD lysate-derived tau seeds (AD-tau) both in vitro and in vivo. Interestingly, the absence of endogenous mouse α-syn in mice reduces the accumulation and spreading of tau, while the absence of tau did not affect the seeding or spreading capacity of α-syn. These in vivo results are consistent with our in vitro data wherein the presence of tau has no synergistic effects on α-syn. Our results point to the important role of α-syn as a modulator of tau pathology burden and spreading in the brains of AD, PDD, and DLB patients.