11/11Gut homeostasis is not passive crowd control. It’s an active, force-regulated process. Cells constantly test each other’s strength; those that fail the tug-of-war extrude.A collaboration between the @hubrechtinstitute.bsky.social , @amolf-nl.bsky.social & @IHB lead by @danielkrueger.bsky.social

9/11 With point ablations at the base, we intentionally weakened individual cells. Within minutes, these cells extruded - loss of tension likely triggers extrusion.

7/11 Optogenetics let us induce contractility with blue light and spatial precision. Extrusion rates jumped up upon activation, showing that globally increased tension directly drives extrusion.

6/11 A basal actomyosin network drives epithelial tension. On hydrogel villus substrates (generated @ IHB, Basel), resembling the in vivo topology, we saw pulsatile contractions—one cell contracts, neighbors expand. A tissue-wide tug-of-war.

5/11 Using CRISPR-generated myosin reporters, we first observed myosin increasing in extruding cells, together with a synchronized response in their neighbors—explaining extrusion dynamics as a coordinated process.

3/11 Using long-term live imaging & tracking (with @amolf-nl.bsky.social), we followed hundreds of extrusion events. Most villus cells extruded alive, not apoptotic. Extrusion did not correlate with density.

2/11 The intestinal lining renews every few days. Old cells are shed by extrusion—a process essential for barrier integrity and linked to diseases like IBD. But what actually triggers extrusion in mammals was unclear.

#Lgr5+ gut #stemcells don't divide asymmetrically. They simple divide and then compete for space: This is called neutral competition. Stem cell numbers are set by the available space between the #Panethcells. Paper: Hugo Snippert et al. Cell (2010). www.cell.com/action/showP...

3D Reconstruction of human fetal pancreatic organoid with an endogenous (knock-in) reporter for the endocrine cell marker Chromogranin-A (green), while stained for the acinar cell marker CarboxyPeptidase A1/2 (magenta) and nuclei, DAPI (blue)

Mouse studies indicate that these three compartments derive from a transient, common pancreatic progenitor. Amanda et al derive 18 human fetal pancreas organoid (hfPO) lines from gestational week 8-17 samples. Four lines generate acinar-, ductal- and endocrine lineage cells 3/

trying out to post an animation: #organoids in #Matrigel dome