1. Liver X Receptor Activation Inhibits Melanogenesis through the Acceleration of ERK- Mediated MITF Degradation 
Chang Seok Lee, Miyoung Park, Jiwon Han, Ji-hae Lee, Il-Hong Bae, Hyunjung Choi, Eui Dong Son, Young-Ho Park, Kyung-Min Lim 
Journal of Investigative Dermatology 
Volume 133, Issue 4, Pages (April 2013)
DOI: /jid
Copyright © 2013 The Society for Investigative Dermatology, Inc Terms and Conditions

2. Figure 1
TO (TO) inhibited melanin synthesis in B16 cells. (a) Reverse transcription–PCR (RT-PCR) analysis. B16 cells were treated with 10μM TO for 12hours. (b) Measurement of melanin contents and (c) photograph for morphological changes. B16 cells were treated with α-melanocyte-stimulating hormone (α-MSH) in the presence or absence of TO. Kojic acid (KA) was used as a positive control. (d, e) Measurement of melanin contents. B16 cells were treated with 100nm ACTH for 72hours or exposed to 15mJcm−2 UVB in the presence or absence of TO. (f) Small interfering RNA (siRNA) transfection. B16 cells were transfected with siRNA oligonucleotides using transfection reagent. RT-PCR analysis was performed after 48hours, and melanin contents were measured after 72hours in the presence of TO without α-MSH. Values represent the mean±SE of at least three independent measurements. **P<0.01.
Journal of Investigative Dermatology  , DOI: ( /jid )
Copyright © 2013 The Society for Investigative Dermatology, Inc Terms and Conditions

3. Figure 2
TO (TO) inhibited the expression of melanogenic enzymes and promoted microphthalmia-associated transcription factor (MITF) proteolysis in B16 cells. (a) Cellular tyrosinase activity and (b) mushroom tyrosinase activity in cell-free system. (c) Western blotting. B16 cells were treated with α-melanocyte-stimulating hormone (α-MSH) for 24hours in the presence or absence of TO. (d) Reverse transcription–PCR (RT-PCR) analysis. B16 cells were treated with α-MSH for indicated time in the presence or absence of TO. GAPDH, glyceraldehyde-3-phosphate dehydrogenase; TRP, tyrosinase-related protein. (e, f) Western blotting. B16 cells were treated with α-MSH for 1hour to detect phospho-cAMP-responsive element-binding (p-CREB) level or for 4hours to detect MITF level in the presence or absence of TO. (g) Western blotting. B16 cells were treated with α-MSH for the indicated time in the presence or absence of TO. Values represent the mean±SE of at least three independent measurements. **P<0.01.
Journal of Investigative Dermatology  , DOI: ( /jid )
Copyright © 2013 The Society for Investigative Dermatology, Inc Terms and Conditions

4. Figure 3
TO (TO) activated the MEK/ERK/RSK signaling pathway in B16 cells. (a) Western blotting. B16 cells were treated with TO for the indicated time. (b) Western blotting. B16 cells were treated with α-melanocyte-stimulating hormone (α-MSH) for 5minutes in the presence or absence of TO. (c) Western blotting. B16 cells were pretreated with 20μM PD98059 for 1hour. Then, B16 cells were treated with TO for 5minutes. (d) Measurement of melanin contents. B16 cells were pretreated with 20μM PD98059 for 1hour. Then, B16 cells were treated with TO for 72hours in the presence or absence of α-MSH. (e) Measurement of melanin contents and western blotting. B16 cells were treated with α-MSH for 72hours in the presence of 5μM GW or 1μgml−1 22(R)-hydroxycholesterol (22(R)HC) for measurement of melanin contents and were treated with 5μM GW or 1μgml−1 22(R)HC for 5minutes for western blotting. Values represent the mean±SE of three independent measurements. *P<0.05; **P<0.01. ERK, extracellular signal–regulated kinase; MEK, MAPK/ERK kinase; RSK, ribosomal S6 kinase.
Journal of Investigative Dermatology  , DOI: ( /jid )
Copyright © 2013 The Society for Investigative Dermatology, Inc Terms and Conditions

5. Figure 4
The effects of TO (TO) on melanogenesis and the extracellular signal–regulated kinase (ERK) signaling pathway in human melanocytes and MNT-1 cells. (a) Western blotting. Normal human melanocytes (NHMs) were treated with 5μM TO for the indicated time. (b) The photograph of pellet and lysates in NHMs and (c) melanin contents in NHMs and MNT-1 cells. On the fourth day, in the presence or absence of TO after NHM or MNT-1 cell seeding, cells were washed with phosphate-buffered saline (PBS) one time and harvested. (d, f) Western blotting. NHMs or MNT-1 cells were treated with TO for the indicated time. (g) Melanin contents. NHMs were pretreated with 20μM PD98059 for 1hour. Then, NHMs were treated with 5μM TO for 96hours. (h) Ras activity assay. NHMs were treated with 5μM TO for the indicated time. The lysates were used for Ras activity assay as described in the Materials and Methods. (i) Western blotting. NHMs were pretreated with 10μM farnesylthiosalicylic acid (FTA) for 1hour. Then, NHMs were treated with 5μM TO for 30minutes. Values represent the mean±SE of three independent measurements. *P<0.05; **P<0.01. ApoE, apolipoprotein E; MEK, MAPK/ERK kinase; MITF, microphthalmia-associated transcription factor.
Journal of Investigative Dermatology  , DOI: ( /jid )
Copyright © 2013 The Society for Investigative Dermatology, Inc Terms and Conditions

6. Figure 5
TO (TO) reduced UVB-induced hyperpigmentation in brown guinea pig. To determine the TO effect on pigmentation, TO (1%) was topically applied to the dorsal skin areas once a day for 4 weeks from the day after the last UVB irradiation. The vehicle solution (PEG400/EtOH=7:3) was applied as a control. At least eight sites from four brown guinea pigs were used for a group. (a) Representative photographs of dorsal skin. (b) The degree of depigmentation was determined by a chromameter (CR-300; Minolta, Osaka, Japan) once a week for 4 weeks. The ΔL value was calculated using the L value (brightness index) measured with the chromameter follows: ΔL=L (at each day measured)-L (at day 0). An increase in the ΔL value indicates a decrease in hyperpigmentation induced by UV. (c) Fontana–Masson (F&M) staining of skin biopsies. (d) Immunohistochemical staining of skin biopsies for the detection of S-100 as a melanocyte marker protein. *P<0.05.
Journal of Investigative Dermatology  , DOI: ( /jid )
Copyright © 2013 The Society for Investigative Dermatology, Inc Terms and Conditions