Heme oxygenase inhibits human airway smooth muscle proliferation via a bilirubin-dependent modulation of ERK1/2 phosphorylation

Camille Taillé, Abdelhamid Almolki, Moussa Benhamed, Christine Zedda, Jérôme Mégret, Patrick Berger, Guy Lesèche, Elie Fadel, Tokio Yamaguchi, Roger Marthan, Michel Aubier, Jorge Boczkowski*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


The aim of this study was to investigate whether the heme oxygenase (HO) pathway could modulate proliferation of airway smooth muscle (ASM) and the mechanism(s) involved in this phenomenon. In cultured human ASM cells, 10% fetal calf serum or 50 ng/ml platelet-derived growth factor AB induced cell proliferation, extracellular and intracellular reactive oxygen species (ROS) production and ERK1/2 phosphorylation. Pharmacological HO-1 induction (by 10 μM hemin or by 20 μM cobalt-protoporphyrin) and HO inhibition (by 25 μM tinprotoporphyrin or by an antisense oligonucleotide), respectively, reduced and enhanced significantly both cell proliferation and ROS production. Neither the carbon monoxide scavenger myoglobin (5-20 μM) nor the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one could reverse ASM proliferation induced by tin-protoporphyrin, making a role of the CO-cGMP pathway in HO-modulated proliferation unlikely. By contrast, bilirubin (1 μM) and the antioxidant N-acetyl-cysteine (1 mM) significantly reduced mitogen-induced cell proliferation, ROS production, and ERK1/2 phosphorylation. Furthermore, both bilirubin and N-acetyl-cysteine and the ERK1/2 inhibitor PD98059 significantly reversed the effects of HO inhibition on ASM proliferation. These results could be relevant to ASM alterations observed in asthma because activation of the HO pathway prevented the increase in bronchial smooth muscle area induced by repeated ovalbumin challenge in immunized guinea pigs, whereas inhibition of HO had the opposite effect. In conclusion, this study provides evidence for an antiproliferative effect of the HO pathway in ASM in vitro and in vivo through a bilirubin-mediated redox modulation of phosphorylation of ERK1/2.

Original languageEnglish (US)
Pages (from-to)27160-27168
Number of pages9
JournalJournal of Biological Chemistry
Issue number29
StatePublished - Jul 18 2003
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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