Endothelial ADAM10 utilization defines a molecular pathway of vascular injury in mice with bacterial sepsis
Danielle N. Alfano, Mark J. Miller, Juliane Bubeck Wardenburg
Danielle N. Alfano, Mark J. Miller, Juliane Bubeck Wardenburg
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Research Article Infectious disease Vascular biology

Endothelial ADAM10 utilization defines a molecular pathway of vascular injury in mice with bacterial sepsis

Abstract

The endothelium plays a critical role in the host response to infection and has been a focus of investigation in sepsis. While it is appreciated that intravascular thrombus formation, severe inflammation, and loss of endothelial integrity impair tissue oxygenation during sepsis, the precise molecular mechanisms that lead to endothelial injury remain poorly understood. We demonstrate here that endothelial ADAM10 was essential for the pathogenesis of Staphylococcus aureus sepsis, contributing to α-toxin–mediated (Hla-mediated) microvascular thrombus formation and lethality. As ADAM10 is essential for endothelial development and homeostasis, we examined whether other major human sepsis pathogens also rely on ADAM10-dependent pathways in pathogenesis. Mice harboring an endothelium-specific knockout of ADAM10 were protected against lethal Pseudomonas aeruginosa and Streptococcus pneumoniae sepsis, yet remained fully susceptible to group B streptococci and Candida albicans sepsis. These studies illustrate a previously unknown role for ADAM10 in sepsis-associated endothelial injury and suggest that understanding pathogen-specific divergent host pathways in sepsis may enable more precise targeting of disease.

Authors

Danielle N. Alfano, Mark J. Miller, Juliane Bubeck Wardenburg

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Figure 2

ADAM10 alters endothelial cell–platelet interactions in response to S. aureus and contributes to sepsis-associated injury.

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ADAM10 alters endothelial cell–platelet interactions in response to S. a...
(A) Representative 2-photon image of control or VE-Cad ADAM10–/– mouse livers 6 to 8 hours after nonlethal S. aureus sepsis. Vasculature (red, Qdots655), platelets (green, GPIbβ). Scale bars: 50 μm. Lower panels display images outlined by a dashed line box. Scale bars: 20 μm. White arrows denote thrombi. (B) Quantification of the total area of platelet accumulation within the vasculature in mouse liver as treated in A. Data represent 5–7 FOV per mouse in control (n = 7F) and VE-Cad ADAM10–/– (n = 6F) mice. Data are presented as the mean ± SEM. Data for individual FOV within each mouse are shown in Supplemental Figure 2A. (C) Representative images of the liver 24 hours after S. aureus infection in control or VE-Cad ADAM10–/– mice. (D) H&E-stained liver sections from control or VE-Cad ADAM10–/– mice 24 hours after infection, with the area of necrosis outlined. Scale bars: 100 μm. Images in C and D are representative of 5 mice per condition from 2 independent experiments. (E) Serum ALT in infected control (n = 11 males, 7 females) or VE-Cad ADAM10–/– (n = 7 males, 6 females) mice 24 hours after nonlethal S. aureus infection. Data represent 3 independent pooled experiments and are presented as the mean ± SEM. (F) Representative 2-photon images of control or VE-Cad ADAM10–/– mouse livers 2–4 hours after lethal S. aureus sepsis. Vasculature (red, Qdots655); vWF (green). Scale bars: 10 μm. White arrows denote vWF deposition. (G) Quantification of the total area of vWF accumulation within the vasculature in mouse liver as treated in F. Data represent 5–6 FOV per mouse in control (n = 6F) and VE-Cad ADAM10–/– (n = 4 females, 2 males) mice per group and represent the mean ± SEM. Data for individual FOV within each mouse are shown in Supplemental Figure 3F. *P ≤ 0.05 and **P ≤ 0.01, by nested t test for in vivo imaging (B and G) or unpaired, 2-tailed t test (E).