NOTCH-driven oscillations control cell fate decisions during intestinal homeostasis

Intestinal homeostasis requires tight regulation of stem cell maintenance and commitment to absorptive and secretory cells, two key intestinal lineages ^1,2 . While major signalling pathways critical for this control have been identified ³ , how they achieve such a tight balance in cell type composition remains unclear. Here, we uncover dynamic expression of Hes1, a direct NOTCH target ³ , in intestinal stem and progenitor cells, and investigate its role in vivo and in vitro . A knock-in reporter ⁴ reveals distinct, cell-specific period lengths in Hes1 oscillations that form a gradient along the crypt-villus axis. Whereas secretory precursors oscillate at low periods, absorptive precursors oscillate at higher periods before transitioning to a differentiated state. To test the function of different oscillation periods, we innovated a microfluidic system that modulates Hes1 oscillations in organoids. We find that varying the oscillation period modulates secretory cell differentiation: While 90-min oscillations promote Paneth cells, 130-min oscillations increase formation of other secretory subtypes. Moreover, low-period oscillations support stemness and a proliferative state. Our study provides the first clear evidence that information for tissue homeostasis in the intestine is encoded in the temporal dynamics of signalling components.