title: SHP-1 inhibition by 4-hydroxynonenal activates Jun N-terminal kinase and glutamate cysteine ligase.
abstract: 4-Hydroxy-2-nonenal (HNE), a major lipid peroxidation product, is toxic at high concentrations, but at near-physiological concentrations it induces detoxifying enzymes. Previous data established that in human bronchial epithelial (HBE1) cells, both genes for glutamate cysteine ligase (GCL) are induced by HNE through the c-Jun N-terminal kinase (JNK) pathway. The protein-tyrosine phosphatase SH2 domain containing phosphatase-1 (SHP-1) is thought to play a role as a negative regulator of cell signaling, and has been implicated as such in the JNK pathway. In the present study, SHP-1 was demonstrated to contribute to HNE-induced-gclc expression via regulation of the JNK pathway in HBE1 cells. Treatment of HBE1 cells with HNE induced phosphorylation of mitogen-activated protein kinase kinase 4 (MKK4), JNK, and c-Jun. HNE was able to inhibit protein tyrosine phosphatase activity of SHP-1 through increased degradation of the protein. Furthermore, transfection with small interference RNA SHP-1 showed an enhancement of JNK and c-Jun phosphorylation, but not of MKK4, leading to increased gclc expression. These results demonstrate that SHP-1 plays a role as a negative regulator of the JNK pathway and that HNE activated the JNK pathway by inhibiting SHP-1. Thus, SHP-1 acts as a sensor for HNE and is responsible for an important adaptive response to oxidative stress.
authors.affiliation: School of Natural Sciences, University of California Merced, Merced, CA 95344, USA.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Rinna
authors.forename: Henry Jay
authors.initials: HJ
authors.lastname: Forman
mesh_terms: D000447:Aldehydes; D002470:Cell Survival / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005721:Glutamate-Cysteine Ligase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D020545:Respiratory Mucosa / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D014162:Transfection; D014168:Transferrin / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
chemical_list: D000447:Aldehydes; D007328:Insulin; D034741:RNA, Small Interfering; D014168:Transferrin; D014284:Triiodothyronine; D004815:Epidermal Growth Factor; D048031:JNK Mitogen-Activated Protein Kinases; C509249:PTPN6 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D005721:Glutamate-Cysteine Ligase; C027576:4-hydroxy-2-nonenal; D006854:Hydrocortisone