Role of broad in intestinal stem cells of adult Drosophila

Ecdysone signaling is necessary for maintaining intestinal homeostasis in adult Drosophila melanogaster by promoting stem cell proliferation and differentiation. However, the role of its downstream target broad (br) in this process remains largely unclear. Here, this study demonstrates that br is required for the maintenance of intestinal stem cells (ISCs) and intestinal injury repair. Clonal analysis shows that br regulates both the proliferation and differentiation of ISCs. Knockdown of br severely impairs the differentiation of stem cells into enterocytes (ECs), whereas overexpression of br promotes ECs differentiation. Further analysis reveals that br knockdown reduces Jak/STAT signaling activity in ISCs. Moreover, upregulating the activity of Jak/STAT or EGFR signaling significantly rescues the br knockdown phenotype. These results suggest that br may regulate the proliferation and differentiation of ISCs through Jak/STAT and EGFR signaling in adult Drosophila. This study highlights the critical role of br in adult Drosophila ISCs and provides a preliminary exploration of its underlying mechanism.