Fig. 5

Effects of 5-HT and 5-HT7R selective agonist LP-12 combined with SB269970 on melanin contents, dendrite, or migration in B16F10 cells. (A) Top, the effect of 5-HT combined with SB269970 on melanin contents in B16F10 cells. Bottom, the effect of LP-12 combined with SB269970 on melanin contents in B16F10 cells. Each value represents the mean ± SEM (n = 3). *p < .05, **p < .01, compared with the Ctrl. ^#p < .05, ^##p < .01, compared with the 5-HT or LP-12. (B) After the 5-HT or 5-HT7R agonist LP-12 acts on the B16F10 cells, the expression of 5-HT7R, MITF, Tyr, and DCT was upregulated, and the antagonist SB269970 could block this trend. 5-HT7R agonist LP-12 treated on the B16F10 cells, initiated the downstream P38/ERK1/2/JNK MAPKs signaling pathway through selectively activating 5-HT7R, thereby promoting the melanogenesis process. Representative images are shown from three independent experiments. (C) B16F10 cells were pre-incubated with SP600125 (10 ?M) and PD98059 (10 ?M) for 2 h prior to the addition of LP-12 (200 nM), and then incubated for 72 h for the measurement of melanin content. (D) Concentration levels of cAMP induced by LP-12 in cell lysate and cell culture supernatant. **p < .01, compared with the Ctrl in cell lysate. ^#p < .05, compared with the Ctrl in cell culture supernatant. (E) B16F10 cells were pre-incubated with H89 (10 ?M) for 2 h prior to the addition of LP-12 (200 nM) and then incubated for 72 h for the measurement of melanin content. (F) 5-HT7R agonist LP-12 had an increase on dendrite length and F-Actin. (G) Left, LP-12 (10 nM, 200 nM)-stimulated cell migration was significantly reduced after incubation with 5-HT7R antagonist SB269970. Right, the number of migrated cell was calculated by Image J. (n = 3) **p < .01, ***p < .001, compared with the Ctrl. ^###p < .001, compared with the LP-12. (H) The effects of 5-HT or LP-12 combined with SB269970 on expression levels of downstream Rab27a/RhoA and PI3K/AKT signaling pathway. Representative image from three independent experiments is shown.