Open Access

Alexander Perniss, Brett Boonen, Sarah Tonack, Moritz Thiel, Krupali Poharkar, Mohamad Wessam Alnouri, Maryam Keshavarz, Tamara Papadakis, Silke Wiegand, Uwe Pfeil, Katrin Richter, Mike Althaus, Johannes Oberwinkler, Burkhard Schütz, Ulrich Boehm, Stefan Offermanns, Trese Leinders-Zufall, Frank Zufall, Wolfgang Kummer

• Host-derived succinate accumulates in the airways during bacterial infection. Here, we show that luminal succinate activates murine tracheal brush (tuft) cells through a signaling cascade involving the succinate receptor 1 (SUCNR1), phospholipase Cβ2, and the cation channel transient receptor potential channel subfamily M member 5 (TRPM5). Stimulated brush cells then trigger a long-range Ca2+ wave spreading radially over the tracheal epithelium through a sequential signaling process. First, brush cells release acetylcholine, which excites nearby cells via muscarinic acetylcholine receptors. From there, the Ca2+ wave propagates through gap junction signaling, reaching also distant ciliated and secretory cells. These effector cells translate activation into enhanced ciliary activity and Cl- secretion, which are synergistic in boosting mucociliary clearance, the major innate defense mechanism of the airways. Our data establish tracheal brush cells as a central hub in triggering a global epithelial defense program in response to a danger-associated metabolite.