Heat stress activates interleukin-8 and the antioxidant system via Nrf2 pathways in human dental pulp cells.
BACKGROUND
This study tested whether heat stress (42 degrees C for 30 minutes) induces reactive oxygen species (ROS), proinflammatory cytokines, Nrf2 activation, and Nrf2 target genes such as antioxidant enzymes in human dental pulp (HDP) cells.


METHODS
ROS was evaluated by using flow cytometry. Proteins and messenger RNA levels for cytokines and antioxidant genes were determined by using Western blotting and reverse transcription-polymerase chain reaction (RT-PCR) analysis, respectively.


RESULTS
Heat stress induced the production of ROS and the increased expression of the interleukin (IL)-8 and IL-8 receptor genes. Exposure of cells to heat stress resulted in the nuclear translocation of Nrf2 and increased expression of Nrf2 target genes including heme oxygenase-1. Pretreatment with an exogenous antioxidant inhibited the heat-induced expression of IL-8 and Nrf2 target genes and Nrf2 translocation.


CONCLUSIONS
Collectively, these results show that heat-induced Nrf2 activation is the major regulatory pathway of cytoprotective gene expression against oxidative stress in HDP cells.
Chang
Seok-Woo
SW
Department of Conservative Dentistry, The Institute of Oral Health Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Lee
Sang-Im
SI
Bae
Won-Jung
WJ
Min
Kyung-San
KS
Shin
Eun-Sang
ES
Oh
Gi-Su
GS
Pae
Hyun-Ock
HO
Kim
Eun-Cheol
EC
D000293:Adolescent; D000975:Antioxidants / Q000378:metabolism*; D015153:Blotting, Western; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D003782:Dental Pulp / Q000166:cytology / Q000378:metabolism*; D005434:Flow Cytometry; D015870:Gene Expression; D006358:Hot Temperature; D006801:Humans; D007150:Immunohistochemistry; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D050217:Metabolic Detoxication, Phase II / Q000235:genetics / Q000502:physiology; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D018123:Receptors, Interleukin / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction
D000975:Antioxidants; D016207:Cytokines; D016209:Interleukin-8; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D018123:Receptors, Interleukin