Tau phosphorylation sites serine202 and serine396 are differently altered in chronic traumatic encephalopathy and Alzheimer's disease.

INTRODUCTION

Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy associated with repetitive head impacts (RHI) typically sustained by contact sport athletes. Post-translation modifications to tau in CTE have not been well delineated or compared to Alzheimer's disease (AD).

METHODS

We measured phosphorylated tau epitopes within dorsolateral frontal cortex from post mortem brains with neither CTE nor AD (n = 108), CTE (n = 109), AD (n = 223), and both CTE and AD (n = 33).

RESULTS

Levels of hyperphosphorylated tau (p-tau) , p-tau , and p-tau were significantly increased in CTE. Total years of RHI exposure was significantly associated with increased p-tau levels (P = .001), but not p-tau . Instead, p-tau was most closely related to amyloid beta (Aβ) levels (P < .001). The p-tau :p-tau ratio was significantly increased in early and late CTE compared to AD.

DISCUSSION

In frontal cortex, p-tau is the most upregulated p-tau species in CTE, while p-tau is most increased in AD. p-tau and p-tau measurements may aid in developing biomarkers for disease.