# Role of solitary chemosensory cells in irritant avoidance and protection of olfactory sensation

> **NIH NIH R01** · MONELL CHEMICAL SENSES CENTER · 2020 · $387,875

## Abstract

Project Summary
Harmful compounds and xenobiotics carried in inhaled air continually assault the nasal cavity and can cause
severe nasal inflammation. Worldwide, hundreds of millions of adults and children suffer with asthma,
rhinosinusitis, and other respiratory conditions. Environmental irritants and bacterial infections can trigger these
types of nasal inflammation. In the nasal passages, the detection of inflammation triggers is mostly mediated
by the trigeminal chemosensory system and the solitary chemosensory cells (SCCs). Known ligands of the
SCCs are the bitter compound denatonium benzoate, used in several household products, and acyl
homoserine lactones (AHLs) generated by bacterial infections. SCCs, which express elements of the bitter
taste (T2R) transduction cascade, are innervated by trigeminal nerve fibers, which relay their responses to the
central nervous system, triggering release of neuropeptides into the mucosa, evoking inflammatory/immune
responses and respiratory-protective reflexes to eliminate the irritating compounds. Denatonium and AHLs are
prototypical compounds for the activation of the T2R pathway in SCCs. Thus, studying their effects on SCCs
can increase our understanding of airway chemoreception and of long-term effects of exposure to SCC
triggers. In this proposed research, we will determine whether SCC activation by denatonium and bacterial
AHLs triggers avoidance behavior, preventing further inhalation of these irritants (Aim 1); whether the presence
of denatonium triggers the same nasal inflammation and immune response as bacterial infections (Aim 2); and
whether forced exposure to denatonium or AHLs can damage the olfactory epithelium and if SCCs are
protective in these circumstances (Aim 3). Because social, work, and other situations often require people to
ignore physiological warnings triggered by SCCs and stay in environments where irritating and toxic
compounds are present, it is important to understand how SCCs function and to determine the chemosensory
mechanisms and the physiological/behavioral effects of commonly encountered irritant compounds like
denatonium. Understanding the transduction cascades and mechanisms involved in these responses will offer
new selective pharmacological targets for several airway pathologies.

## Key facts

- **NIH application ID:** 9989094
- **Project number:** 5R01DC016598-04
- **Recipient organization:** MONELL CHEMICAL SENSES CENTER
- **Principal Investigator:** Marco Tizzano
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $387,875
- **Award type:** 5
- **Project period:** 2017-09-21 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9989094

## Citation

> US National Institutes of Health, RePORTER application 9989094, Role of solitary chemosensory cells in irritant avoidance and protection of olfactory sensation (5R01DC016598-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9989094. Licensed CC0.

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