Maarten Hulsmans, Sebastian Clauss, Ling Xiao, Aaron D Aguirre, Kevin R King, Alan Hanley, William J Hucker, Eike M Wülfers, Gunnar Seemann, Gabriel Courties, Yoshiko Iwamoto, Yuan Sun, Andrej J Savol, Hendrik B Sager, Kory J Lavine, Gregory A Fishbein, Diane E Capen, Nicolas Da Silva, Lucile Miquerol, Hiroko Wakimoto, Christine E Seidman, Jonathan G Seidman, Ruslan I Sadreyev, Kamila Naxerova, Richard N Mitchell, Dennis Brown, Peter Libby, Ralph Weissleder, Filip K Swirski, Peter Kohl, Claudio Vinegoni, David J Milan, Patrick T Ellinor, Matthias Nahrendorf
Organ-specific functions of tissue-resident macrophages in the steady-state heart are unknown. Here, we show that cardiac macrophages facilitate electrical conduction through the distal atrioventricular node, where conducting cells densely intersperse with elongated macrophages expressing connexin 43. When coupled to spontaneously beating cardiomyocytes via connexin-43-containing gap junctions, cardiac macrophages have a negative resting membrane potential and depolarize in synchrony with cardiomyocytes. Conversely, macrophages render the resting membrane potential of cardiomyocytes more positive and, according to computational modeling, accelerate their repolarization...
April 20, 2017: Cell