Flow-driven lumen remodeling and valve opening in the vas deferens

ABSTRACT Biological ducts must transport fluids while preserving structural integrity, yet how mechano-signaling coordinates wall deformation with luminal flow in vivo remains unclear. Here we combine intravital two-photon excitation microscopy, light-sheet imaging and FRET-based kinase biosensors to resolve ejaculation-like events in the mouse vas deferens. Acute phenylephrine stimulation elicits a sequence of luminal dynamics: an initial retrograde pressure-redistribution wave followed by a ballistic antegrade flow that propels dense sperm suspensions from proximal to distal duct. This contraction-driven flow opens a normally collapsed, wrinkled distal segment, driving progressive lumen expansion and unfolding of epithelial wrinkles. We show that the vas deferens actively modulates luminal geometry in response to these flow dynamics: ROCK activity in smooth muscle is required for global contraction and cAMP-associated signaling modulates this contractile response. By contrast, ERK activity in circumferential smooth muscle is dispensable for the ductal contraction but essential for active, flow-dependent remodeling of the distal lumen, forming the core of the mechano-signaling module that couples sperm flow to valve opening. These findings establish the vas deferens as an experimentally tractable model of ductal tissue hydraulics and reveal a mechano-signaling framework by which a tubular organ converts transient muscular input into robust, directional luminal transport. SIGNIFICANCE STATEMENT Male reproductive ducts must rapidly propel sperm-containing fluids forward, yet how they do so in living animals has remained unclear due to a lack of imaging studies. By combining real-time in vivo imaging and molecular activity reporters, we observe the mouse vas deferens at work and link each phase of ejaculation-like transport to specific signaling pathways. We find that ROCK activity is closely linked to the overall squeeze of the duct, cAMP-associated signaling modulates this contractile response, and ERK is uniquely required to open and remodel a normally closed distal valve in response to flow. This mechano-signaling framework offers a general blueprint for how tubular organs coordinate muscle contraction, tissue shape change, and directional luminal transport.