Commensal Microbiota Have Impact on the Laryngeal Immune System in Mice

by Linda Kossoff •

CLINICAL QUESTION

What are the cell types/subtypes in the larynx, and what is their immune response to commensal microbiota?

BOTTOM LINE

The cellular landscape of the mouse model larynx contains multiple macrophages and secretory epithelial cell populations; commensal microbiota has an extensive impact on the laryngeal immune system.

BACKGROUND: Multiple lines of evidence suggest an association between specific bacteria and vocal fold (VF) pathology and rapid laryngeal immune responses to in vitro challenges with a single or mix of bacteria or viruses; however, current knowledge of the laryngeal microbiota and its association with host immunity remains limited.

STUDY DESIGN: Ex vivo study

SETTING: Department of Surgery, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, Wis.

SYNOPSIS: Researchers performed single-cell RNA sequencing on larynges collected from healthy, conventionally raised (ConvR) and germ-free (GF) mice. They established a reference single-cell atlas of the normal larynx and dissected the role of microbiota in laryngeal cell development and functions at single-cell resolution. A total of 16,822 ConvR and 14,282 GF cells were recovered for further analysis. Epithelial cells dominated at 65.6% and with a total of six types. Fibroblasts and endothelial cells were the two largest non-epithelial cell populations in the larynx. Two major types of immune cells were identified: phagocytes and lymphocytes. Researchers found that, compared with other epithelial cells, secretory epithelial cells were more responsive to long-term commensal microbiota colonization and actively engaged in host–microbe interactions in the larynx. Their findings suggest that commensal microbiota have an extensive impact on the laryngeal immune system, manifested by the regulation of cell differentiation, elevated expression of host defense genes, pattern recognition receptors, and metabolic genes, and that macrophages are the most responsive immune cells in the larynx to bacterial exposure. Study limitations included the exclusion of female mice.

CITATION: An R, Ni Z, Xie E, et al. Single-cell view into the role of microbiota shaping host immunity in the larynx. iScience. 2024;27:110156.

DISCUSSION: “This is an interesting basic science study that maps cell types in the larynx and puts this in the context of the microbiota of the larynx as well. There is clearly a lot we need to learn about how the bacterial milieu of the larynx affects our health, and this article represents an important early step. It’s also single-cell sequencing … very flashy!” Dr. Matthew Naunheim.