# Mapping Small Extracellular Vesicle Secretion Potential in Healthy Human Gingiva Using Spatial Transcriptomics

## TL;DR

This study uses spatial transcriptomics to explore how small extracellular vesicles are produced in healthy human gum tissue, revealing new insights into tissue regeneration.

## Contribution

The first meta-analysis of gingival transcriptomic data focused on small extracellular vesicle biogenesis.

## Key findings

- Gene clusters related to extracellular vesicle biogenesis were identified in the sulcular epithelium of the gingiva.
- MUC1, SDCBP2, and VPS37B showed the highest expression in the superficial layer of the sulcular epithelium.
- Known sEV markers like CD9 and CD63 were expressed in the tissue but not exclusively in the sulcular epithelium.

## Abstract

Regenerative processes occur at various levels in all organisms, yet their complexity continues to raise new questions about their mechanisms. It has been demonstrated that small extracellular vesicles (sEVs), secreted by all cells and influencing their function, play a significant role in regeneration. In the context of regenerative processes, oral mucosal tissues consistently receive interest, as they are among the most rapidly healing tissues in the human body. In this study, we utilized spatial transcriptomics to map gene expression to specific spatial locations within the gingiva tissue section, using publicly available transcriptomic data. This analysis revealed new insights into this tissue and the biogenesis of sEVs within it. The identified clusters encompassed two main regions—the epithelium and lamina propria—as well as minor niches within them. Using Gene Ontology (GO) analysis, we identified two clusters most enriched in extracellular vesicle-related GO processes. These included the superficial and deeper layers of the sulcular epithelium, one of the most peripheral regions of the gingiva. Of the 43 genes identified in the literature as having a potential or documented role in sEVs biogenesis, 12 were selected for further analysis. MUC1, SDCBP2, and VPS37B showed clear specificity and the highest expression in the superficial layer of the sulcular epithelium. CHMP4C also exhibited high expression in this layer, though its levels were comparable to the outer layer of the oral epithelium. Other well-established sEVs marker genes, such as ANXA2, CD9, CD63, CD81, FLOT1, RAB22A, RAB27B, and RAB5A, were also expressed in the examined tissue; however, their expression was not specifically exclusive to the sulcular epithelium. Our study is the first to perform a meta-analysis of available gingival transcriptomic data in the specific context of sEVs biogenesis. The presented data and conclusions provide new insights into the role of different structures within healthy human gingiva and shed new light on both known and potential markers of sEVs biogenesis. These findings may contribute to the development of regeneration-targeted research, especially on oral tissues.