[Signaling pathways in expression of inducible nitric oxide synthase induced by high mobility group box 1 in rat alveolar macrophages].
OBJECTIVE
To explore roles of extracellular signal-regulated kinase (ERK) 1/2, p38 mitogen activated protein kinase (p38 MAPK) and nuclear factor (NF) -KB in expression of inducible nitric oxide synthase (iNOS) in rat alveolar macrophages induced by high mobility group box 1 (HMGB1 ).


METHODS
Primary rat alveolar macrophages (PRAMs) cultured in vitro were incubated with PD98059 ( inhibitor against ERK), SB203580 (inhibitor against p38 MAPK) , PDTC (inhibitor against NF-kappaB), or PD98059 plus SB203580 for 2 hours, respectively. HMGB1 was added into the cultures and incubated with cells for 6 hours. Total RNA of PRAMs was extracted and iNOS mRNA expression was semi-quantified with reverse transcription-polymerase chain reaction ( RT-PCR). Greiss reaction was applied to determine nitrite/nitrate (NO2-/NO3- ) concentration in PRAMs culture supernatants.


RESULTS
Expression of iNOS mRNA and NO production in PRAMs culture supernatants were down-regulated by inhibition of ERK or p38 MAPK by PD98059 or SB203580, respectively (P <0. 05). Moreover, inhibition of iNOS expression and NO production was observed after simultaneous pretreatment with PD98059 and SB203580 (P < 0. 05). Expression of iNOS mRNA in PRAMs and NO production in PRAMs culture supernatants were down-regulated by inhibition of NF-kappaB by PDTC (P <0. 05).


CONCLUSIONS
Cellular signal molecules of ERK, p38 MAPK, and NF-kappaB all participate in the expression of iNOS and NO production in PRAMs induced by HMGB1.
Yu
Yue
Y
Department of Pathophysiology, Institute of Basic Medical Sciences, CAMS and PUMC, Beijing 100005, China.
Ren
Da-bin
DB
Sun
Ren-yu
RY
Wang
Shi-wen
SW
D000818:Animals; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D005419:Flavonoids / Q000494:pharmacology; D024243:HMGB1 Protein / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D016676:Macrophages, Alveolar / Q000378:metabolism*; D008297:Male; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis*; D011392:Proline / Q000031:analogs & derivatives / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013859:Thiocarbamates / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*
D005419:Flavonoids; D024243:HMGB1 Protein; D007093:Imidazoles; D016328:NF-kappa B; D011725:Pyridines; D012333:RNA, Messenger; D013859:Thiocarbamates; C066229:prolinedithiocarbamate; D011392:Proline; D052247:Nitric Oxide Synthase Type II; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one