1. Apurinic/apyrimidinic endonuclease 1 is a key modulator of keratinocyte inflammatory responses.
- Author
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Lee HM, Yuk JM, Shin DM, Yang CS, Kim KK, Choi DK, Liang ZL, Kim JM, Jeon BH, Kim CD, Lee JH, and Jo EK
- Subjects
- Antimicrobial Cationic Peptides immunology, Antimicrobial Cationic Peptides metabolism, Apoptosis drug effects, Apoptosis immunology, Cell Line, Cyclin D1 immunology, Cyclin D1 metabolism, Cyclin-Dependent Kinase 4 immunology, Cyclin-Dependent Kinase 4 metabolism, DNA-(Apurinic or Apyrimidinic Site) Lyase drug effects, DNA-(Apurinic or Apyrimidinic Site) Lyase genetics, DNA-(Apurinic or Apyrimidinic Site) Lyase metabolism, Epidermis pathology, Extracellular Signal-Regulated MAP Kinases immunology, Extracellular Signal-Regulated MAP Kinases metabolism, Humans, Hypoxia-Inducible Factor 1 immunology, Hypoxia-Inducible Factor 1 metabolism, Inflammation enzymology, Interferon Inducers pharmacology, Interleukin-8 immunology, Interleukin-8 metabolism, Keratinocytes drug effects, Keratinocytes pathology, NF-kappa B immunology, NF-kappa B metabolism, Poly I-C pharmacology, Proto-Oncogene Proteins c-akt immunology, Proto-Oncogene Proteins c-akt metabolism, Psoriasis pathology, RNA, Small Interfering immunology, RNA, Small Interfering metabolism, Reactive Oxygen Species immunology, Reactive Oxygen Species metabolism, Signal Transduction drug effects, Signal Transduction immunology, Toll-Like Receptor 2 immunology, Toll-Like Receptor 2 metabolism, Transcriptional Activation drug effects, Transcriptional Activation immunology, Transfection, Tumor Necrosis Factor-alpha immunology, Tumor Necrosis Factor-alpha metabolism, Up-Regulation drug effects, Up-Regulation immunology, Zymosan pharmacology, Cathelicidins, DNA-(Apurinic or Apyrimidinic Site) Lyase immunology, Epidermis enzymology, Keratinocytes enzymology, Psoriasis enzymology
- Abstract
Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1) functions in both DNA repair and redox signaling, making it an attractive emerging therapeutic target. However, the role of APE1 in cutaneous inflammatory responses is largely unknown. In this study, we report that APE1 is a key upstream regulator in TLR2-dependent keratinocyte inflammatory responses. We found that nuclear expression of APE1 in epidermal layers was markedly up-regulated in psoriatic skin. APE1 was essential for the transcriptional activation and nuclear translocation of hypoxia-inducible factor-1alpha and NF-kappaB, both of which are crucial for inflammatory signaling in keratinocytes. Moreover, APE1 played a crucial role in the expression of TLR2-mediated inflammatory mediators, including TNF-alpha, CXCL8, and LL-37, in HaCaT cells and human primary keratinocytes. Silencing of APE1 attenuated cyclin D1/cyclin-dependent kinase 4 expression and phosphorylation of ERK1/2 and Akt, thereby affecting keratinocyte proliferation. Importantly, TLR2-induced generation of reactive oxygen species contributed to the nuclear translocation and expression of APE1, suggesting an autoregulatory circuit in which the subcellular localization of APE1 is associated with the production of APE1 per se through reactive oxygen species-dependent signaling. Taken together, these findings establish a role for APE1 as a master regulator of TLR2-dependent inflammatory responses in human keratinocytes. more...
- Published
- 2009
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