Aging-related olfactory loss is associated with olfactory stem cell transcriptional alterations in humans
Allison D. Oliva, … , Hiroaki Matsunami, Bradley J. Goldstein
Allison D. Oliva, … , Hiroaki Matsunami, Bradley J. Goldstein
Published January 6, 2022
Citation Information: J Clin Invest. 2022;132(4):e155506. https://doi.org/10.1172/JCI155506.
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Clinical Medicine Aging Neuroscience

Aging-related olfactory loss is associated with olfactory stem cell transcriptional alterations in humans

Abstract

BACKGROUND Presbyosmia, or aging-related olfactory loss, occurs in a majority of humans over age 65 years, yet remains poorly understood, with no specific treatment options. The olfactory epithelium (OE) is the peripheral organ for olfaction and is subject to acquired damage, suggesting a likely site of pathology in aging. Adult stem cells reconstitute the neuroepithelium in response to cell loss under normal conditions. In aged OE, patches of respiratory-like metaplasia have been observed histologically, consistent with a failure in normal neuroepithelial homeostasis.Methods Accordingly, we have focused on identifying cellular and molecular changes in presbyosmic OE. The study combined psychophysical testing with olfactory mucosa biopsy analysis, single-cell RNA-Sequencing (scRNA-Seq), and culture studies.Results We identified evidence for inflammation-associated changes in the OE stem cells of presbyosmic patients. The presbyosmic basal stem cells exhibited increased expression of genes involved in response to cytokines or stress or the regulation of proliferation and differentiation. Using a culture model, we found that cytokine exposure drove increased TP63, a transcription factor acting to prevent OE stem cell differentiation.Conclusions Our data suggest aging-related inflammatory changes in OE stem cells may contribute to presbyosmia via the disruption of normal epithelial homeostasis. OE stem cells may represent a therapeutic target for restoration of olfaction.Funding NIH grants DC018371, NS121067, DC016224; Office of Physician-Scientist Development, Burroughs-Wellcome Fund Research Fellowship for Medical Students Award, Duke University School of Medicine.

Authors

Allison D. Oliva, Rupali Gupta, Khalil Issa, Ralph Abi Hachem, David W. Jang, Sebastian A. Wellford, E. Ashley Moseman, Hiroaki Matsunami, Bradley J. Goldstein

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Figure 6

A cell culture model for human HBC analysis.

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A cell culture model for human HBC analysis. (A) Experimental approach; ...
(A) Experimental approach; human olfactory mucosa biopsy is dissociated, followed by immunoselection for NOTCH1+ cells, seeded onto laminin for in vitro expansion. (B) Differential interference contrast (DIC) view of typical adherent cell islands and (C) immunostaining of cultures showing near-uniform TP63+KRT5+ phenotype. (D and E) scRNA-Seq analysis of passage 6 HBC cultures; the culture single-cell data set was integrated with 3 control acutely harvested human olfactory biopsy scRNA-Seq data sets. FeaturePlots in D show gene expression of selected transcripts, and UMAP (E) showing sample origins indicates that culture-expanded cells (purple) cluster adjacent to acutely harvested olfactory HBCs, indicating transcriptional similarity, and largely lack SERPINB3. iOSNs, immature olfactory sensory neurons; mOSNs, mature neurons; BG, Bowman’s gland; MV, microvillar cells; Sus, sustentacular. (F) RT-qPCR assay of TNF-α–treated HBC cultures; note 2 fold-change increase in TP63 expression relative to controls (P = 0.04, n = 3). Scale bars: 50 μM.