image: (A) UMAP visualization of 10,587 zebrafish olfactory epithelium cells. A total of nine cell types are color-coded based on major cell types. (B) Dot plot of markers delineating molecular cell types. Dot sizes represent the proportion of cells expressing a specific gene in the indicated subset and the color represents the gene expression level. (C) Heatmap of differentially expressed genes used to classify cell types for each cluster compared to all other clusters for the 19 olfactory epithelium cell clusters. The rows correspond to the top five genes most upregulated in individual clusters (P < 0.05), and the columns show nine distinct cell types. (D) Feature plots showing expression patterns of key marker genes for cell type. The color represents the gene expression levels. (E) Relative percentage of all cell types captured in zebrafish olfactory epithelium in a control (CTR) group and a group exposed to a conspecific alarm substance (CAS). Cell type colors correspond to panel C.
Credit: Wenjun Chen, et al
Zebrafish (Danio rerio) is a small freshwater teleost fish with a highly developed sense of smell that regulates behaviors related to appetite, reproduction and fear. Many freshwater fish can detect conspecific alarm substances (CAS) released by injured individuals through their sense of smell, triggering a startle response characterized by flight and freezing, which plays a crucial role in predator avoidance.
In this context, a team of researchers in China conducted single-cell sequencing of the olfactory epithelium of zebrafish in the AB strain blank control group and the CAS-exposed group to reveal the heterogeneity of zebrafish olfactory epithelium and the response of cell populations after CAS treatment.
“We identified nine distinct cell types with unique transcriptional profiles, including immature and mature olfactory sensory neurons (OSNs), horizontal basal cells, globose basal cells, and sustentacular cells, as well as lymphocyte and myeloid cells expressing immune signals,” shares Wenjun Chen, lead author of the study published in the KeAi journal Water Biology and Security. “Further subcluster analysis revealed selective and combinatorial expression of key components in odorant-mediated signal transduction by distinct OSN populations.”
The team found that after CAS exposure, the olfactory epithelium showed specific transcriptional changes in cell ratios and certain OSN populations.
"The changes in cell ratios may be due to the fact that CAS exposure promoted the apoptosis of OSNs," Chen says. "At the same time, differential expression analysis showed that OSN progenitor cells were activated and differentiated accordingly to replenish the depletion of OSNs."
This study offers a valuable avenue for exploring cell diversity and assessing genetic profiles from functional and behavioral perspectives in fish.
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Contact the author: Wenjun Chen, Institute of Hydrobiology, Chinese Academy of Sciences, wenjunchen0423@gmail.com
The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 200 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).
Journal
Water Biology and Security
Method of Research
Experimental study
Subject of Research
Animals
Article Title
Single-cell RNA sequencing of zebrafish olfactory epithelium reveals cellular heterogeneity and responses to a conspecific alarm substance
COI Statement
The authors declare no competing interests.