Single-Cell Transcriptomic Analysis of Salivary Epithelial Cells Reveals Large-Scale Dysregulation in Bitter Taste...

Area of Science:

• Oral Biology
• Immunology
• Genomics

Background:

• Taste dysfunction (dysgeusia) is common in infections and systemic diseases, but its cellular mechanisms are unclear.
• The COVID-19 pandemic highlighted taste loss, particularly in long COVID (LC), offering a unique research opportunity.
• Understanding the molecular basis of taste dysfunction in LC is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the molecular changes in salivary epithelial cells (SECs) associated with taste dysfunction in long COVID.
• To identify specific genes and pathways affected in individuals experiencing bitter taste loss post-COVID-19.

Main Methods:

• Single-cell RNA sequencing of SECs from individuals with and without long COVID taste dysfunction.
• Functional enrichment analysis of transcriptomic data to identify affected biological processes.
• Analysis of key genes involved in taste perception and cellular function.

Main Results:

• Downregulation of genes related to cytoskeletal dynamics and taste cell-nerve synapse assembly in individuals with long COVID taste dysfunction (LC-D).
• Reduced expression of specific Type II and III taste receptor genes essential for bitter taste.
• Decreased levels of microbial defense markers (TLR2, TLR4), indicating potential chronic inflammation.

Conclusions:

• Impaired taste in LC-D may result from sustained dysregulated epithelial turnover due to molecular deficits.
• Single-cell analysis of saliva offers a promising approach for diagnosing and understanding taste system disorders.
• These findings provide insights into the cellular and molecular underpinnings of persistent taste dysfunction after COVID-19.