Procainamide, a Drug Causing Lupus, Induces Prostaglandin H Synthase-2 and Formation of T Cell-Sensitizing Drug Metabolites in Mouse Macrophages
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- 作者：Carsten Goebel ; Christoph Vogel ; Marty Wulferink ; Stephanie Mittmann ; Bernhardt Sachs ; Sabine Schraa ; Josef Abel ; Gisela Degen ; Jack Uetrecht ; and Ernst Gleichmann
- 刊名：Chemical Research in Toxicology
- 出版年：1999
- 出版时间：June 1999
- 年：1999
- 卷：12
- 期：6
- 页码：488 - 500
- 全文大小：196K
- 年卷期：v.12,no.6(June 1999)
- ISSN：1520-5010
文摘
Procainamide (PA) may cause drug-induced lupus, and its reactive metabolites, hydroxylamine-PA (HAPA) and nitroso-PA, are held responsible for this. Here, we show that N-oxidationof PA to these metabolites can take place in macrophages and lead to formation of neoantigensthat sensitize T cells. Murine peritoneal macrophages (PM
), exposed to PA in vitro, generatedneoantigens related to HAPA as indicated by (1) their capacity to elicit a specific recall responseof HAPA-primed T cells in the adoptive transfer popliteal lymph node (PLN) assay and (2) theappearance of metabolite-bound protein in PA-pulsed PM, as determined by Western blot.Analysis of five phase I enzymes that might be responsible for HAPA formation by PM pointedto prostaglandin H synthase-2 (PGHS-2) as a likely candidate. Experimental evidence thatPA can be oxidized to HAPA by PGHS was obtained by exposing PA to PGHS in vitro. Theresulting metabolites were identified by mass spectral analysis and covalent protein bindingin ELISA. In vitro, PA exposure of PM of slow acetylator A/J and fast acetylator C57BL/6mice failed to show significant strain differences in enzyme mRNA expression, enzyme activities,or formation of HAPA-related neoantigens. By contrast, after long-term PA treatment in vivoonly in slow acetylators the PM harbored HAPA-related neoantigens and T cells weresensitized to them. PM of fast acetylator C57BL/6 mice only contained HAPA-relatedneoantigens, and their T cells were only sensitized to them if, in addition to long-term PAtreatment, their donors had received injections of phorbol myristate acetate (PMA), a knownenhancer of oxidative enzymes in phagocytes. In conclusion, PA treatment leads to N-oxidationof PA by enzymes, in particular PGHS-2, present in antigen-presenting cells (APC) and, hence,to generation of neoantigens which sensitize T cells. The enhanced neoantigen formation andT cell sensitization seen in slow acetylators might be explained by their higher concentrationof PA substrate that is available for extrahepatic N-oxidation in APC.
), exposed to PA in vitro, generatedneoantigens related to HAPA as indicated by (1) their capacity to elicit a specific recall responseof HAPA-primed T cells in the adoptive transfer popliteal lymph node (PLN) assay and (2) theappearance of metabolite-bound protein in PA-pulsed PM, as determined by Western blot.Analysis of five phase I enzymes that might be responsible for HAPA formation by PM pointedto prostaglandin H synthase-2 (PGHS-2) as a likely candidate. Experimental evidence thatPA can be oxidized to HAPA by PGHS was obtained by exposing PA to PGHS in vitro. Theresulting metabolites were identified by mass spectral analysis and covalent protein bindingin ELISA. In vitro, PA exposure of PM of slow acetylator A/J and fast acetylator C57BL/6mice failed to show significant strain differences in enzyme mRNA expression, enzyme activities,or formation of HAPA-related neoantigens. By contrast, after long-term PA treatment in vivoonly in slow acetylators the PM harbored HAPA-related neoantigens and T cells weresensitized to them. PM of fast acetylator C57BL/6 mice only contained HAPA-relatedneoantigens, and their T cells were only sensitized to them if, in addition to long-term PAtreatment, their donors had received injections of phorbol myristate acetate (PMA), a knownenhancer of oxidative enzymes in phagocytes. In conclusion, PA treatment leads to N-oxidationof PA by enzymes, in particular PGHS-2, present in antigen-presenting cells (APC) and, hence,to generation of neoantigens which sensitize T cells. The enhanced neoantigen formation andT cell sensitization seen in slow acetylators might be explained by their higher concentrationof PA substrate that is available for extrahepatic N-oxidation in APC.