# Revealing stromal and lymphoid sources of Col3a1-expression during inflammation using a novel reporter mouse

## TL;DR

This study identifies cells that produce collagen type III during inflammation using a new fluorescent reporter mouse, which could help in understanding and treating fibrosis-related diseases.

## Contribution

A novel reporter mouse was developed to track Col3a1-expressing cells during inflammation.

## Key findings

- The reporter mouse effectively tracks Col3a1 expression during inflammation.
- Stromal and immune cells were identified as sources of Col3a1 expression.
- The model provides insights into early fibrosis development.

## Abstract

One of the earliest signs of dysregulation of the homeostatic process of fibrosis, associated with pathology in chronic conditions such as rheumatoid arthritis, is the overexpression of collagen type III (COL-3). Critically, there is still relatively little known regarding the identity of the cell types expressing the gene encoding COL-3 (Col3a1). Identifying and characterizing Col3a1-expressing cells during the development of fibrosis could reveal new targets for the diagnosis and treatment of fibrosis-related pathologies. As such, a reporter mouse expressing concomitantly Col3a1 and mKate-2, a fluorescent protein, was generated. Using models of footpad inflammation, we demonstrated its effectiveness as a tool to measure the expression of COL-3 during the repair process and provided an initial characterization of some of the stromal and immune cells responsible for Col3a1 expression.

Graphical Abstract