# miR-302 regulates pancreatic progenitor pool and pancreatic size

## TL;DR

This study shows that miR-302 controls the number of pancreatic progenitor cells, which affects the size of the developing pancreas.

## Contribution

The study provides the first comprehensive miRNA profile during early pancreatic development and identifies miR-302 as a key regulator.

## Key findings

- miR-302 is highly enriched during early pancreatic development.
- Loss of miR-302 reduces pancreatic size by decreasing progenitor cell proliferation.
- miR-302 modulates genes related to Wnt signaling and cell cycle progression.

## Abstract

Disruptions in pancreatic development can lead to health issues such as pancreatic agenesis and congenital diabetes mellitus. Understanding pancreatic organogenesis is critical for elucidating disease mechanisms and developing regenerative therapies. The pancreas consists of endocrine and exocrine cells, both of which are derived from multipotent progenitor cells (MPCs). MPC proliferation and differentiation are tightly controlled by multiple mechanisms, including post-transcriptional regulation by miRNAs. However, these regulatory factors are not fully understood. Here, we profiled miRNA expression in MPCs and identified that mir-302 was highly enriched during the earliest stages of pancreatic development. Loss of mir-302 resulted in reduced pancreatic size without altering the proportions of endocrine and exocrine cells at E17.5, suggesting that mir-302 regulates the number of MPCs rather than their differentiation. Transcriptomic analysis at E10.5 revealed that mir-302 modulates genes associated with the Wnt signaling pathway and cell cycle progression. Notably, loss of mir-302 prolonged the S phase in MPCs, resulting in slower cell proliferation and a smaller MPC pool at E10.5. These findings provide the first comprehensive miRNA profile during early pancreatic development and establish mir-302 as a critical regulator of MPC number and pancreas size.

Summary: miRNA profiling during early pancreatic development identifies miR-302 as a critical regulator of progenitor number and overall organ size.