Melanosomes are specialized membrane-bound organelles within which melanin is synthesized and stored.The levels of melanin can be effectively reduced by inhibiting melanin synthesis or promoting melanosome degradation...Melanosomes are specialized membrane-bound organelles within which melanin is synthesized and stored.The levels of melanin can be effectively reduced by inhibiting melanin synthesis or promoting melanosome degradation via autophagy.Ceramide,a central molecule in sphingolipid metabolism,has been widely implicated in the regulation of autophagy.Few researchers have addressed the potential effects of ceramide analogs on suppressing melanin synthesis.However,whether ceramide can induce melanosome autophagy and the potential autophagy-dependent mechanism underlying this phenomenon remain unknown.Here,an active compound from the marine microalgae Emiliania huxleyi extract was firstly isolated and identified as a long-chain C22-ceramide(C22-Cer).In vitro results of mouse B16 melanoma cell experiments showed that treatment with 2-5µmol/L C22-Cer significantly suppressed the increase ofα-MSH-induced melanin levels and tyrosinase activity without cytotoxicity.C22-Cer induced typical hallmarks of autophagy such as accumulation of autophagosomes,enhanced autophagic flux and microtubule-associated protein light chain 3,LC3-II expression,and p62 degradation through activating c-Jun N-terminal kinase(JNK)directly.Furthermore,C22-Cer activated JNK-Bcl-2 signaling,dissociated the Beclin1/Bcl-2 complex,and induced melanosome autophagy without affecting the expression of MITF.Besides,the Ca^(2+)influx induced by treatment with C22-Cer further increased the substantial accumulation of autophagosomes.Together,we found a novel marine-derived compound,C22-Cer,targeting JNK pathway and Ca^(2+)signaling to induce melanosome autophagy and suppress melanin accumulation in B16 cells.This study implicates that C22-Cer might be a potential therapeutic mediator against skin pigmentation in mammals.展开更多
目的研究莲房原花青素(procyanidins from the seedpod of the lotus,LSPC)对体外培养的黑色素瘤B16细胞活性的影响。方法以MTT法和细胞平板集落形成实验测定LSPC的抗肿瘤活性;电镜观察LSPC对瘤细胞形态学的影响;流式细胞仪检测LSPC对...目的研究莲房原花青素(procyanidins from the seedpod of the lotus,LSPC)对体外培养的黑色素瘤B16细胞活性的影响。方法以MTT法和细胞平板集落形成实验测定LSPC的抗肿瘤活性;电镜观察LSPC对瘤细胞形态学的影响;流式细胞仪检测LSPC对瘤细胞凋亡和细胞周期的影响;激光扫描共聚焦显微镜检测LSPC对瘤细胞内Ca2+浓度的影响。结果LSPC对B16细胞生长的抑制作用与作用时间和浓度呈时效和量效关系,并可诱导瘤凋亡效应,最大抑制率达84.5%,使瘤细胞阻滞于S期;瘤细胞内Ca2+浓度显著升高;细胞有典型的凋亡形态。结论LSPC是以诱导凋亡的方式抑制黑色素瘤B16细胞增殖,其凋亡作用可能与细胞被阻断于S期和Ca2+浓度升高有关。展开更多
基金supported by the National Natural Science Foundation of China(Nos.42076086 and 32202068)Fujian Province Natural Science Foundation of China(Nos.2019J01696 and 2022J01332)the Fujian Province Young and Middle-Aged Teacher Education Research Project(No.JAT200247).
文摘Melanosomes are specialized membrane-bound organelles within which melanin is synthesized and stored.The levels of melanin can be effectively reduced by inhibiting melanin synthesis or promoting melanosome degradation via autophagy.Ceramide,a central molecule in sphingolipid metabolism,has been widely implicated in the regulation of autophagy.Few researchers have addressed the potential effects of ceramide analogs on suppressing melanin synthesis.However,whether ceramide can induce melanosome autophagy and the potential autophagy-dependent mechanism underlying this phenomenon remain unknown.Here,an active compound from the marine microalgae Emiliania huxleyi extract was firstly isolated and identified as a long-chain C22-ceramide(C22-Cer).In vitro results of mouse B16 melanoma cell experiments showed that treatment with 2-5µmol/L C22-Cer significantly suppressed the increase ofα-MSH-induced melanin levels and tyrosinase activity without cytotoxicity.C22-Cer induced typical hallmarks of autophagy such as accumulation of autophagosomes,enhanced autophagic flux and microtubule-associated protein light chain 3,LC3-II expression,and p62 degradation through activating c-Jun N-terminal kinase(JNK)directly.Furthermore,C22-Cer activated JNK-Bcl-2 signaling,dissociated the Beclin1/Bcl-2 complex,and induced melanosome autophagy without affecting the expression of MITF.Besides,the Ca^(2+)influx induced by treatment with C22-Cer further increased the substantial accumulation of autophagosomes.Together,we found a novel marine-derived compound,C22-Cer,targeting JNK pathway and Ca^(2+)signaling to induce melanosome autophagy and suppress melanin accumulation in B16 cells.This study implicates that C22-Cer might be a potential therapeutic mediator against skin pigmentation in mammals.
文摘目的研究莲房原花青素(procyanidins from the seedpod of the lotus,LSPC)对体外培养的黑色素瘤B16细胞活性的影响。方法以MTT法和细胞平板集落形成实验测定LSPC的抗肿瘤活性;电镜观察LSPC对瘤细胞形态学的影响;流式细胞仪检测LSPC对瘤细胞凋亡和细胞周期的影响;激光扫描共聚焦显微镜检测LSPC对瘤细胞内Ca2+浓度的影响。结果LSPC对B16细胞生长的抑制作用与作用时间和浓度呈时效和量效关系,并可诱导瘤凋亡效应,最大抑制率达84.5%,使瘤细胞阻滞于S期;瘤细胞内Ca2+浓度显著升高;细胞有典型的凋亡形态。结论LSPC是以诱导凋亡的方式抑制黑色素瘤B16细胞增殖,其凋亡作用可能与细胞被阻断于S期和Ca2+浓度升高有关。
