RT Journal Article SR Electronic T1 Rapid Up-Regulation of Endothelial Nitric-Oxide Synthase in a Mouse Model of Escherichia coli Lipopolysaccharide-Induced Bladder Inflammation JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 452 OP 458 DO 10.1124/jpet.104.066506 VO 310 IS 2 A1 Walter S. Kang A1 Frank J. Tamarkin A1 Marcia A. Wheeler A1 Robert M. Weiss YR 2004 UL http://jpet.aspetjournals.org/content/310/2/452.abstract AB Increases in the signaling molecule nitric oxide (NO) during inflammation may be linked not only to inducible nitric-oxide synthase (iNOS) but also to endothelial (e)NOS. Escherichia coli lipopolysaccharide (LPS) induces an inflammatory response in the bladder and rapidly increases phosphorylation of Akt/protein kinase B (Akt), a key enzyme regulating proliferation, apoptosis, and inflammation. Activated Akt phosphorylates human eNOS at serine 1177 and subsequently increases NOS activity. Because Akt and eNOS are both localized in the bladder urothelium, phosphorylation of eNOS by Akt provides an attractive mechanism for rapid increases in urinary NO production. Female mice were intraperitoneally injected with LPS (25 mg/kg) or pyrogen-free water (control). Four hours before LPS injection, some mice were injected with wortmannin, which inhibits Akt phosphorylation. Levels of urinary cyclic GMP, a downstream product of NO, increase 75% within 1 h after intraperitoneal injection of LPS, and this increase is blocked by wortmannin. Bladder eNOS and phosphorylated eNOS protein increase 94 and 151%, respectively, 1 h after LPS treatment, whereas iNOS was not detected. Wortmannin decreases eNOS phosphorylation by 60%. Furthermore, bladder Ca2+-dependent NOS activity (eNOS, neuronal NOS) is increased 79 ± 20% 1 h after LPS treatment, whereas there is no increase in Ca2+-independent (iNOS) activity (n = 4). Increases in urinary cyclic GMP, NOS activity, and eNOS protein and phosphorylation 1 h after induction of inflammation with LPS, indicate that eNOS plays a role in the early response to bladder inflammation. The American Society for Pharmacology and Experimental Therapeutics