# Phosphorylated tau protein detection in olfactory neurons at a single-cell resolution: needle-free biopsy for Alzheimer's disease pathophysiology study

> **NIH NIH R21** · JOHNS HOPKINS UNIVERSITY · 2021 · $450,313

## Abstract

Abstract
In many areas of medicine, pathophysiological studies of biospecimens from living patients have facilitated our
understanding of disease mechanisms. However, due to the difficulty of brain biopsies, such strategies have
not been developed for Alzheimer’s disease (AD). Thus, there is a great need for novel methodologies to
collect neurons from living patients in order to capture pathological changes relevant to AD. The olfactory
neuroepithelium has received great interest as a surrogate tissue to study brain disorders. Multiple studies
have shown the neuronal validity of olfactory neurons/neuronal cells at the molecular level. As the olfactory
neuroepithelium includes neural stem cells/neuroprogenitor cells, the tissue can quickly regenerate following a
biopsy, which allows us to repeat biopsies over time without impairing olfactory function. However, the classic
nasal biopsy platform is limited by its invasiveness and the insufficient purity of neurons in the biopsied tissue.
To overcome these limitations, we recently developed a new platform: a soft nasal brush swab followed by a
single-cell analysis specific for neurons. This new platform is now even easier and even less invasive than a
blood draw, and neural purity is guaranteed at a single-cell resolution.
Olfactory dysfunction is an early symptom preceding robust memory deficits in AD; Aβ lesions and tau
pathology occur extensively in the olfactory system, including the olfactory neuroepithelium. Therefore, we
hypothesized that phosphorylated tau protein at threonine 181(pT181-tau) detected in olfactory neurons
through single-cell Western blotting is increased in AD patients, compared to subjects with mild cognitive
impairment (MCI) and controls, and additionally that such pT181-tau levels detected in olfactory neurons are
associated with the pT181-tau levels detected in cerebrospinal fluid (CSF) and with neurocognitive function.
Indeed, we found that pT181-tau levels in olfactory neurons obtained from AD patients were significantly higher
than those from cognitively normal controls in our pilot study. Encouraged by this promising data, we will study
pT181-tau levels in olfactory neurons at the single-cell resolution in 30 patients with AD, 30 subjects with MCI,
and 30 cognitively normal controls (Aim 1); We will compare pT181-tau levels in olfactory neurons detected at
the single-cell level with those detected in CSF from the same individuals (Aim 2); We will determine whether
pT181-tau levels in olfactory neurons detected at the single-cell level are associated with neuropsychological
function (Aim 3). Through this proof-of-concept study, we hope to establish a novel, high-throughput, and non-
invasive platform (nasal brush swab followed by single-cell Western blotting) to study the pathophysiology of
AD in neurons obtained from living patients at the single-cell level.

## Key facts

- **NIH application ID:** 10117832
- **Project number:** 1R21AG070754-01
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Koko Ishizuka
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $450,313
- **Award type:** 1
- **Project period:** 2021-03-01 → 2025-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10117832

## Citation

> US National Institutes of Health, RePORTER application 10117832, Phosphorylated tau protein detection in olfactory neurons at a single-cell resolution: needle-free biopsy for Alzheimer's disease pathophysiology study (1R21AG070754-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10117832. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*