title: Nonmetal haptens induce ATP release from keratinocytes through opening of pannexin hemichannels by reactive oxygen species.
abstract: Although extracellular adenosine 5'-triphosphate (eATP) has a crucial role in the sensitization phase of contact hypersensitivity (CHS), the mechanism by which hapten causes keratinocyte cell death and ATP release is unknown. We examined the time course of cell death, reactive oxygen species (ROS) production, and ATP release in HaCaT cells and in normal human keratinocytes after exposure to nonmetal haptens, NiCl2, or irritants. Both haptens and irritants caused cell death of keratinocytes but with different time courses. N-acetylcysteine (NAC) significantly reduced only nonmetal hapten-induced cell death as assessed by propidium iodide exclusion. We examined the effects of antioxidants and pannexin (Panx) inhibitors on cell death, ROS production, and ATP release by chemical-treated HaCaT cells. Nonmetal hapten-induced cell death, but not NiCl2- or irritant-related cell death, was dependent on reactivity to thiol residues in the cells. NAC reduced cell death and ATP release, whereas antioxidants and Panx inhibitors did not inhibit cell death but significantly attenuated ATP release. Panx1 small interfering RNA (siRNA) also suppressed ATP release from hapten-exposed HaCaT cells. Intraperitoneal injection of a Panx1 inhibitor attenuated murine CHS. These findings suggest that nonmetal hapten reactivity to thiol residues causes membrane disruption of keratinocytes and ROS production that leads to ATP release through opening of Panx hemichannels.
authors: Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors: Kaoru
authors: K
authors: Onami
authors: Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors: Yutaka
authors: Y
authors: Kimura
authors: Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors: Yumiko
authors: Y
authors: Ito
authors: Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors: Takeshi
authors: T
authors: Yamauchi
authors: Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors: Kenshi
authors: K
authors: Yamasaki
authors: Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan. Electronic address: saiba@med.tohoku.ac.jp.
authors: Setsuya
authors: S
authors: Aiba
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001578:Benzopyrans / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D017630:Connexins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003553:Cystine / Q000031:analogs & derivatives / Q000494:pharmacology; D003877:Dermatitis, Contact / Q000378:metabolism* / Q000473:pathology; D004137:Dinitrochlorobenzene / Q000494:pharmacology; D004195:Disease Models, Animal; D005260:Female; D006241:Haptens / Q000378:metabolism*; D006801:Humans; D007509:Irritants / Q000494:pharmacology; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009532:Nickel / Q000494:pharmacology; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011744:Pyrimidinones / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: C547415:(1,5-dihydro-5-(5-pyrimidine-2,4(1H,3H)-dionyl)-2H-chromeno(2,3-d)pyrimidine-2,4(3H)-dione); D000975:Antioxidants; D001578:Benzopyrans; D017630:Connexins; D004137:Dinitrochlorobenzene; D006241:Haptens; D007509:Irritants; D009419:Nerve Tissue Proteins; C492764:PANX1 protein, human; D011744:Pyrimidinones; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D003553:Cystine; C022838:nickel chloride; D009532:Nickel; D000255:Adenosine Triphosphate; C030905:N-monoacetylcystine