Advertisement

Gut microbiota regulate hepatic von Willebrand Factor synthesis and arterial thrombus formation via Toll-like receptor-2

Sven Jäckel, Klytamnistra Kiouptsi, Maren Lillich, Tim Hendrikx, Avinash Khandagale, Bettina Kollar, Nives Hörmann, Cora Reiss, Saravanan Subramaniam, Eivor Wilms, Katharina Ebner, Marie-Luise von Brühl, Philipp Rausch, John F. Baines, Sandra Haberichter, Bernhard Lämmle, Christoph J. Binder, Kerstin Jurk, Zaverio M. Ruggeri, Steffen Massberg, Ulrich Walter, Wolfram Ruf and Christoph Reinhardt

Key points

  • VWF synthesis in liver sinusoidal endothelial cells is regulated by gut microbiota through TLR2 signaling.

  • Reduced plasma VWF in germ-free and Tlr2-/- mice cause reduced thrombus formation at the ligation injured carotid artery.

Abstract

The symbiotic gut microbiota plays pivotal roles in host physiology and the development of cardiovascular diseases, but microbiota-triggered pattern recognition signaling mechanisms impacting thrombosis are poorly defined. Here, we show that germ-free and Toll-like receptor (Tlr) 2-deficient mice have reduced thrombus growth following carotid artery injury relative to conventionally raised controls. Germ-free Tlr2-/- and wild-type mice were indistinguishable, but colonization with microbiota restored a significant difference in thrombus growth between genotypes. We identify reduced plasma levels of von Willebrand Factor (VWF) and reduced VWF synthesis specifically in hepatic endothelial cells as a critical factor that is regulated by gut microbiota and determines thrombus growth in Tlr2-/- mice. Static platelet aggregate formation on extracellular matrix was similarly reduced in germ-free wild-type, Tlr2-/-, and heterozygous Vwf+/- mice that are all characterized by a modest reduction in plasma VWF level. Defective platelet matrix interaction can be restored by exposure to wild-type plasma or to purified VWF dependent on the VWF integrin binding site. Moreover, administration of VWF rescues defective thrombus growth in Tlr2-/- mice in vivo. These experiments delineate an unexpected pathway, in which microbiota-triggered TLR2 signaling alters the synthesis of pro-adhesive VWF by the liver endothelium and favors platelet integrin-dependent thrombus growth.

  • Submitted November 29, 2016.
  • Accepted May 22, 2017.