Presentation Details
The Life and Death of a Taste Cell

Courtney E Wilson1, 2, 3, Yannick K Dzowo1, 2, Ruibiao Yang1, 2, Robert S Lasher1, 2, Thomas E Finger1, 2.

1University of Colorado School of Medicine Department of Cell and Developmental Biology, Aurora, CO, USA.2Rocky Mountain Taste and Smell Center, Aurora, CO, USA.3University of Colorado School of Medicine Department of Otolaryngology, Aurora, CO, USA

Abstract


Taste buds undergo continuous cell turnover throughout life. Our understanding of the processes and signals involved in taste cell replacement has advanced greatly in the past decade. How taste cells die and exit the bud, however, has received scant attention. Using serial EM images of murine taste buds, we identified cells that appear to be in various stages of cell death, based on their ultrastructural features. These cells display morphological characteristics of apoptosis: reduced cell volume, changes in heterochromatin organization within the nuclei, nuclear fragmentation, golgi body degradation, and cell fragmentation. Dying cells tend to lie near the edge of the taste bud, often abutting “edge” cells at the border between the taste bud and the surrounding epithelial tissue. From this observation, we suggest that taste cells migrate outward from the longitudinal center of the taste bud over the course of their lives. Dying cells also tend to be wrapped by Type I cells, which in some cases appear to be in the process of engulfing the dying cell or fragments that have separated from the dying cell. We propose that Type I cells act as non-specialized phagocytes during the programmed death of a neighboring cell. Our serial EM datasets only capture a snapshot of time in the taste bud. Cells caught in the process of cell death are relatively rare. For example, in a single taste bud, we found evidence of only 2 apoptotic cells in a total population of ~100 taste cells. Since the lifespan of the average taste cell is 10-15 days, over 10% of the cells should be dying every day. We therefore conclude that morphological apoptosis occurs rapidly in the taste bud.

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