1. A Protective Mechanism of Visible Red Light in Normal Human Dermal Fibroblasts: Enhancement of GADD45A-Mediated DNA Repair Activity 
Yeo Jin Kim, Hyoung-June Kim, Hye Lim Kim, Hyo Jeong Kim, Hyun Soo Kim, Tae Ryong Lee, Dong Wook Shin, Young Rok Seo 
Journal of Investigative Dermatology 
Volume 137, Issue 2, Pages (February 2017)
DOI: /j.jid
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2. Figure 1
Detection of DNA damage after visible light exposure. (a, c) Representative photographs of comet and γ-H2AX assays performed in NHDFs exposed to visible light (red = 660 nm, blue = 457 nm) and UVB (0.1 J/cm2). Scale bar = 50 μm. (b) DNA damage accumulation was detected in a comet assay. Each tail intensity of the visible red light groups was lower than those of the visible blue light groups at different exposure doses. (d) Initial DNA damage was measured by the γ-H2AX assay. The FITC intensities of cells exposed to visible red light groups are lower than those of cells exposed to visible blue light at different exposure doses. The bars represent means ± standard deviations. ∗P < NHDF, normal human dermal fibroblast.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
Copyright © 2016 The Authors Terms and Conditions

3. Figure 2
Measurement of DNA damage on NHDFs exposed to visible red light pre- and posttreatment with UVB. (a, c) Representative photographs of comet and γ-H2AX assays in NHDFs exposed to visible red light (60 J/cm2) and/or UVB (0.1 J/cm2). (b) The tail intensity (%) was decreased upon both pre- and posttreatment with visible red light compared with the UVB group. (d) The FITC intensities on both pre- and posttreatment with visible red light were lower compared with the UVB group. The bars represent means ± standard deviations. ∗P < Scale bar = 50 μm. NHDF, normal human dermal fibroblast.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
Copyright © 2016 The Authors Terms and Conditions

4. Figure 3
Protective effect of visible red light pretreatment on UVB-induced DNA damage in a 3D skin model. (a, c) Representative results of the comet assay in an artificial 3D human skin model exposed to visible red light and/or UVB. Scale bar = 50 μm. (b) In a 3D epidermis/dermis model, DNA damage of fibroblasts was significantly reduced on pretreatment with visible red light (60 J/cm2) compared with the UVB (0.6 J/cm2)-irradiated group. (d) In a 3D dermis model, pretreatment with visible red light (30 J/cm2) led to a decrease in DNA strand breaks compared with the UVB (0.4 J/cm2)-exposed group. The bars represent means ± standard deviations. ∗P < 0.05, ∗∗P < D, three dimensional.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
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5. Figure 4
Mechanism underlying protective effects of visible red light on DNA repair response. (a) Alteration of GADD45A and APE1 protein levels in response to visible red light exposure (60 J/cm2) were detected by Western blot analysis. (b) A physical interaction between GADD45A and APE1 was identified by co-immunoprecipitation. (c) GADD45A-APE1 complexes (red spots) were detected in situ in the absence or presence of visible red light (60 J/cm2). Blue color indicates nuclei staining. Bars represent means ± standard deviations. ∗P < Scale bar = 50 μm. (d) The APE1 activity using tetrahydrofuran-containing oligonucleotides was assayed in NHDFs following visible red light treatment, by assaying the levels of the cleavage product (8-mer). GAPDH, glyceraldehyde-3-phosphate dehydrogenase; IB, immunoblotting; IP, immunoprecipitation; WCE, whole cell extract.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
Copyright © 2016 The Authors Terms and Conditions

6. Figure 5
Protective effect of visible red light pretreatment on NHDFs in terms of UVB-induced DNA strand break damage. (a) After 24–72 hours incubation with APE1 siRNA, the protein level of APE1 was examined by Western blot analysis. APE1 knockdown was examined after 72 hours incubation, which was applied for the comet assay. (b) Representative photographs of the comet assay performed under exposure of visible light (60 J/cm2) and/or UVB (0.1 J/cm2). Scale bar = 50 μm. (c) DNA damage was evaluated as tail intensity by an in vitro alkaline comet assay using control or APE1 siRNA-treated cells. The bars represent means ± standard deviations. ∗P < GAPDH, glyceraldehyde-3-phosphate dehydrogenase; h, hour; NHDF, normal human dermal fibroblast; siRNA, small interfering RNA.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
Copyright © 2016 The Authors Terms and Conditions

7. Figure 6
Identification of ATF2-dependent effects of visible red light by using an ATF2 knockdown system. (a) After 24–72 hours incubation with ATF2 siRNA, ATF2 knockdown was examined by Western blot. Treatment of NHDFs with ATF2 siRNA for 48 hours was applied for DNA binding and protein-protein interaction assays. (b) DNA binding activity of ATF2 on GADD45A promoter was verified using a streptavidin magnetic bead assay. (c) To observe the alteration of interaction between GADD45A and APE1, an in situ proximity ligation assay was performed using control or ATF2 siRNA-treated cells in response to visible red light (60 J/cm2). The bars represent means ± standard deviations. ∗P < Scale bar = 50 μm. Con, control; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; h, hour; NHDF, normal human dermal fibroblast; siRNA, small interfering RNA.
Journal of Investigative Dermatology  , DOI: ( /j.jid )
Copyright © 2016 The Authors Terms and Conditions