May 13, 2017

Nrf2 in keratinocytes modulates UVB-induced DNA damage and apoptosis in melanocytes through MAPK signaling

Free Radical Biology & Medicine
Saowanee JeayengUraiwan Panich


Responses of melanocytes (MC) to ultraviolet (UV) irradiation can be influenced by their neighbouring keratinocytes (KC). We investigated the role of Nrf2 in regulating paracrine effects of KC on UVB-induced MC responses through phosphorylation of MAPKs in association with oxidative stress in primary human MC cocultured with primary human KC using a transwell co-culture system and small-interfering RNA-mediated silencing of Nrf2 (siNrf2). The mechanisms by which Nrf2 modulated paracrine factors including α-melanocyte-stimulating hormone (α-MSH) and paracrine effects of KC on UVB-mediated apoptosis were also assessed. Our findings showed that co-culture of MC with siNrf2-transfected KC enhanced UVB-mediated cyclobutane pyrimidine dimer (CPD) formation, apoptosis and oxidant formation, together with phosphorylation of ERK, JNK and p38 in MC. Treatment of MC with conditioned medium (CM) from Nrf2-depleted KC also increased UVB-mediated MC damage, suggesting that KC modulated UVB-mediated MC responses via paracrine effects. Additionally, depletion of Nrf2 in KC suppressed UVB-induced α-MSH levels as early as 30min post-irradiation, although pretreatment with N-acetylcysteine (NAC) elevated its levels in CM from siNrf2-transfected K...Continue Reading

Mentioned in this Paper

Inherited Factor II Deficiency
Biochemical Pathway
ACTH (1-13)NH2
Systemic Inflammatory Response Syndrome
Apoptosis, Intrinsic Pathway
NF-E2-Related Factor 2

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Apoptosis is a specific process that leads to programmed cell death through the activation of an evolutionary conserved intracellular pathway leading to pathognomic cellular changes distinct from cellular necrosis