Carbon monoxide from CORM-2 reduces HMGB1 release through regulation of IFN-β/JAK2/STAT-1/INOS/NO signaling but not COX-2 in TLR-activated macrophages.
Reduction of high-mobility group box 1 (HMGB1) and NO levels may be important therapeutic strategy for treatment of sepsis. Recently, we found that carbon monoxide (CO) can reduce HMGB1 levels in septic animal models. Here, we tried to elucidate the molecular machinery of how CO inhibits HMGB1 release in toll-like receptor (TLR)-activated macrophages. Carbon monoxide-releasing molecule 2 (CORM-2) specifically inhibited the expression of iNOS (NO), but not of cyclooxygenase 2 (COX-2) (PGE₂) in RAW 264.7 cells activated either by peptidoglycan (TLR-2 agonist), polyinosinic-polycytidylic acid (TLR-3 agonist), or LPS (TLR-4 agonist); this inhibition seemed to be mediated via the JAK2/STAT1 pathway. Treatment with neutralizing antibody to IFN-β, a JAK2 inhibitor (AG490), or a STAT1 inhibitor (fludarabine) selectively inhibited iNOS, but not COX-2 in this system. Moreover, deletion of STAT1 by siRNA also showed preferential inhibition of iNOS but not COX-2 in LPS-treated cells. Carbon monoxide-releasing molecule 2 reduced IFN-β production and phosphorylation of JAK2 and STAT1 in LPS-activated RAW264.7 cells. Carbon monoxide-releasing molecule 2 failed to inhibit iNOS and HMGB1 levels in the presence of recombinant IFN-β and NO donor (NOC-18), respectively. Finally, plasma levels of HMGB1 and iNOS protein expression in lung tissues of cecal ligation and puncture-induced septic mice were decreased in the presence of CORM-2. Taken together, it is concluded that CO selectively inhibits iNOS over COX-2, at least through IFNβ/JAK2/STAT1 signals, and this regulation plays an important role in the CORM-2-mediated inhibitory effect on HMGB1 release in macrophages.
Tsoyi
Konstantin
K
Department of Pharmacology, School of Medicine and Institute of Life Sciences, Gyeongsang National University, Jinju, Gyeongsang, Korea.
Nizamutdinova
Irina Tsoy
IT
Jang
Hwa Jin
HJ
Mun
Lidiya
L
Kim
Hye Jung
HJ
Seo
Han Geuk
HG
Lee
Jae Heun
JH
Chang
Ki Churl
KC
D000818:Animals; D015153:Blotting, Western; D002248:Carbon Monoxide / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D024243:HMGB1 Protein / Q000378:metabolism*; D016899:Interferon-beta / Q000378:metabolism*; D053614:Janus Kinase 2 / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D009942:Organometallic Compounds / Q000737:chemistry / Q000494:pharmacology*; D010457:Peptidoglycan / Q000494:pharmacology; D011070:Poly I-C / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D051193:Toll-Like Receptors / Q000819:agonists / Q000378:metabolism
D024243:HMGB1 Protein; D009942:Organometallic Compounds; D010457:Peptidoglycan; D051193:Toll-Like Receptors; C447082:tricarbonyldichlororuthenium (II) dimer; D009569:Nitric Oxide; D016899:Interferon-beta; D002248:Carbon Monoxide; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2; D053614:Janus Kinase 2; D011070:Poly I-C