# Hyperphosphorylated tau aggregation-based Alzheimer’s disease early drug discovery

> **NIH NIH R01** · MICHIGAN STATE UNIVERSITY · 2020 · $436,696

## Abstract

Hyperphosphorylated tau aggregation-based Alzheimer’s disease early drug discovery 
Alzheimer’s disease (AD) is an irreversible neurodegenerative disease affecting 47 million people worldwide, 
and costs 604 billion US dollars every year for medical expenses. To date, there is no cure or prevention for 
AD. The two defining features of AD are Aβ plaques and neurofibrillary tangles that are composed of 
hyperphosphorylated tau. While the AD drug discovery landscape has been dominated by anti-Aβ measures, 
recurring failures of clinical trials argue strongly that a realignment of the drug target and strategies is needed to 
make a breakthrough in AD therapeutics development. Indeed, multiple lines of evidence suggest that the pre-
tangle stage of hyperphosphorylated tau aggregates cause diffusible cytotoxicity that likely underlies 
neurodegeneration. Screening for compounds that prevent hyperphosphorylated tau from forming the cytotoxic 
aggregates thus affords a more viable route for AD drug discovery. 
 The tangle-centric drug design has not come to fruition. A wide spectrum of compounds have been 
identified in multiple screens as inhibitors of tangle formation, but later found to be false-positive. One shared 
issue for these screens is the use of an unmodified tau protein that requires an inducer, e.g., heparin, for efficient 
aggregation in a reducing environment. The assay subject (tau) lacks the pathological mark of 
hyperphosphorylation, and the disease relevance of the inducer has not been substantiated. To overcome these 
hurdles, we have developed the PIMAX technology that produces hyperphosphorylated tau (p-tau) in E. coli. 
Purified p-tau fibrillizes autonomously (without an inducer), and causes apoptosis of different cells including a 
neuroblastoma cell line. This inducer-free, p-tau aggregation assay has a Z’ value of 0.699, and a coefficient of 
variation (CV) of 8.3%. These parameters qualify our p-tau aggregation assay as a robust HTS platform. Using 
this assay, we conducted a pilot screen for 1,280 compounds for their ability to modulate the aggregation of p-
tau. We then used novel biochemical and cell-based secondary assays to verify the candidate compounds. We 
found that an active neurological drug is a potent p-tau aggregation inhibitor, which also protects cells from p-
tau cytotoxicity. These preliminary studies afford solid evidence for the values of p-tau in the quest for AD 
therapeutics. This R01 project is the very first that uses the pathophysiologically relevant hyperphosphorylated 
tau for AD drug discovery. We will follow our pilot screen protocols to conduct a high-throughput screen of 
100,000 compounds for their ability to inhibit p-tau aggregation and to protect cells. This early discovery project 
will conclude with two major products: (1) A collection of chemical hits with confirmed p-tau aggregation inhibitory 
and cytoprotective activities, and (2) a follow-up proposal with comprehensive plans to ident...

## Key facts

- **NIH application ID:** 9904313
- **Project number:** 5R01AG062435-02
- **Recipient organization:** MICHIGAN STATE UNIVERSITY
- **Principal Investigator:** Min-Hao Kuo
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $436,696
- **Award type:** 5
- **Project period:** 2019-04-01 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9904313

## Citation

> US National Institutes of Health, RePORTER application 9904313, Hyperphosphorylated tau aggregation-based Alzheimer’s disease early drug discovery (5R01AG062435-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9904313. Licensed CC0.

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