Selective NOD1 agonists cause shock and organ injury/dysfunction in vivo.
BACKGROUND
NLRs (nucleotide oligomerisation domain [NOD] proteins containing a leucine-rich repeat) are cytosolic pattern recognition receptors. NOD1 senses diaminopimelic acid-containing peptidoglycan present in gram-negative bacteria, whereas NOD2 senses the muramyl dipeptide (MDP) present in most organisms. Bacteria are the most common cause of septic shock, which is characterized clinically by hypotension resistant to vasopressor agents. In animal models, gram-negative septic shock is mimicked by lipopolysaccharide (LPS), which signals through Toll-like receptor 4 (TLR4) and its adaptor MyD88. The role of NLRs in the pathophysiology of septic shock is not known.


OBJECTIVE
To compare the effects of selective NOD1 agonists with LPS in vivo.


METHODS
Vascular smooth muscle cells or whole aortas from wild-type or genetically modified mice were stimulated in vitro with agonists of NOD1 (FK565) or NOD2 (MDP). Vasoconstriction was measured using wire myography. Nitric oxide (NO) formation was measured using Griess reaction and NO synthase-II protein by Western blotting. In vivo, blood pressure, heart rate, and urine output were measured in sham-, LPS-, or FK565-treated animals. Biomarkers of end-organ injury, coagulation activation, NO, and cytokines were measured in plasma.


RESULTS
FK565, but not MDP, induced NO synthase-II protein/activity in vascular smooth muscle and vascular hyporeactivity to pressor agents. FK565 had no effect on vessels from NOD1(-/-) mice, but was active in vessels from TLR4(-/-), TLR2(-/-), or MyD88(-/-) mice. FK565 induced hypotension, increased heart rate, and caused multiple (renal, liver) injury and dysfunction in vivo.


CONCLUSIONS
Activation of NOD1 induces shock and multiple organ injury/dysfunction.
Cartwright
Neil
N
Department of Critical Care, National Heart and Lung Institute, Imperial College, Dovehouse Street, London SW3 6LY, UK.
Murch
Oliver
O
McMaster
Shaun K
SK
Paul-Clark
Mark J
MJ
van Heel
David A
DA
Ryffel
Bernhard
B
Quesniaux
Valerie F J
VF
Evans
Timothy W
TW
Thiemermann
Christoph
C
Mitchell
Jane A
JA
D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D048868:Adaptor Proteins, Signal Transducing / Q000819:agonists*; D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000990:Antithrombin III; D001011:Aorta / Q000378:metabolism / Q000473:pathology; D001794:Blood Pressure / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D006339:Heart Rate / Q000187:drug effects; D007668:Kidney / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D009102:Multiple Organ Failure / Q000139:chemically induced*; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D053474:Nod1 Signaling Adaptor Protein / Q000819:agonists*; D009842:Oligopeptides / Q000494:pharmacology*; D010179:Pancreas / Q000187:drug effects; D010447:Peptide Hydrolases / Q000097:blood; D012769:Shock / Q000139:chemically induced*
D048868:Adaptor Proteins, Signal Transducing; D000276:Adjuvants, Immunologic; D016207:Cytokines; D008070:Lipopolysaccharides; D053474:Nod1 Signaling Adaptor Protein; C507873:Nod1 protein, mouse; D009842:Oligopeptides; C046193:antithrombin III-protease complex; D000119:Acetylmuramyl-Alanyl-Isoglutamine; D000990:Antithrombin III; D052247:Nitric Oxide Synthase Type II; D010447:Peptide Hydrolases; C039537:heptanoyl-gamma-D-glutamyl-L-meso-diaminopimelyl-D-alanine; C036866:romurtide