Cross-Regulations among NRFs and KEAP1 and Effects of their Silencing on Arsenic-Induced Antioxidant Response and Cytotoxicity in Human Keratinocytes

Autor: Yongyong Hou, Jingbo Pi, Melvin E. Andersen, Kathy Yarborough, Courtney G. Woods, Jingqi Fu, Qiang Zhang, Peng Xue, Da-Wei Guan, Rui Zhao
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Keratinocytes
Health
Toxicology and Mutagenesis
Apoptosis
medicine.disease_cause
environment and public health
Antioxidants
0302 clinical medicine
NRF1
RNA
Small Interfering
0303 health sciences
Kelch-Like ECH-Associated Protein 1
Reverse Transcriptase Polymerase Chain Reaction
Intracellular Signaling Peptides and Proteins
Proteasome complex
respiratory system
Flow Cytometry
Sodium Compounds
medicine.anatomical_structure
030220 oncology & carcinogenesis
Gene Knockdown Techniques
cytotoxicity
Environmental Pollutants
Keratinocyte
antioxidant response
Arsenites
NF-E2-Related Factor 2
Blotting
Western
NF-E2-Related Factor 1
keratinocyte
Biology
Real-Time Polymerase Chain Reaction
digestive system
Skin Diseases
NRF2
Arsenic
Cell Line
03 medical and health sciences
medicine
Gene silencing
Humans
030304 developmental biology
Dose-Response Relationship
Drug
Research
Lentivirus
Public Health
Environmental and Occupational Health
Molecular biology
KEAP1
HaCaT
Oxidative Stress
Cell culture
Oxidative stress
Zdroj: Environmental Health Perspectives
ISSN: 1552-9924
0091-6765
Popis: Background: Nuclear factor E2-related factors (NRFs), including NRF2 and NRF1, play critical roles in mediating the cellular adaptive response to oxidative stress. Human exposure to inorganic arsenic, a potent oxidative stressor, causes various dermal disorders, including hyperkeratosis and skin cancer. Objective: We investigated the cross-regulations among NRF2, NRF1, and KEAP1, a cullin-3–adapter protein that allows NRF2 to be ubiquinated and degraded by the proteasome complex, in arsenic-induced antioxidant responses. Results: In human keratinocyte HaCaT cells, selective knockdown (KD) of NRF2 by lentiviral short hairpin RNAs (shRNAs) significantly reduced the expression of many antioxidant enzymes and sensitized the cells to acute cytotoxicity of inorganic arsenite (iAs3+). In contrast, silencing KEAP1 led to a dramatic resistance to iAs3+-induced apoptosis. Pretreatment of HaCaT cells with NRF2 activators, such as tert-butylhydroquinone, protects the cells against acute iAs3+ toxicity in an NRF2-dependent fashion. Consistent with the negative regulatory role of KEAP1 in NRF2 activation, KEAP1-KD cells exhibited enhanced transcriptional activity of NRF2 under nonstressed conditions. However, deficiency in KEAP1 did not facilitate induction of NRF2-target genes by iAs3+. In addition, NRF2 silencing reduced the expression of KEAP1 at transcription and protein levels but increased the protein expression of NRF1 under the iAs3+-exposed condition. In contrast, silencing KEAP1 augmented protein accumulation of NRF2 under basal and iAs3+-exposed conditions, whereas the iAs3+-induced protein accumulation of NRF1 was attenuated in KEAP1-KD cells. Conclusions: Our studies suggest that NRF2, KEAP1, and NRF1 are coordinately involved in the regulation of the cellular adaptive response to iAs3+-induced oxidative stress.
Databáze: OpenAIRE
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