Hui-Jun Ma1, Hui-Yong Ma2, Yang Yang3, Peng-Cheng Li4, Shao-Xia Zi5, Chi-Yu Jia4, Rong Chen6. 1. Department of Dermatology, the 309th Hospital of Chinese PLA, Beijing, 100091, PR China. Electronic address: melanocytes@163.com. 2. Department of Orthopaedics, Heji Affiliated Hospital of Changzhi Medical School, Changzhi City, Shanxi Province, 046000, PR China. 3. Department of Dermatology, the 309th Hospital of Chinese PLA, Beijing, 100091, PR China. 4. Department of Plastic Surgery, the 309th Hospital of Chinese PLA, Beijing, 100091, PR China. 5. Department of Dermatology, China Meitan General Hospital, Beijing, 100061, PR China. 6. Department of Stomatology, the 309th Hospital of Chinese PLA, Beijing, 100091, PR China. Electronic address: ynan622@sina.com.
Abstract
BACKGROUND: Skin pigmentation is accomplished by production of melanin in melanosome and by transfer of these organelles from melanocytes (MCs) to surrounding keratinocytes (KCs). However, the detailed mechanism is still unknown. OBJECTIVE: We aimed to investigate the morphological structure changes on human epidermal MCs and KCs, which were either mono-cultured or co-cultured, with or without the treatment of both α-Melanocyte-stimulating hormone (α-MSH) and prostaglandin E2 (PGE2), by atomic force microscopy (AFM) and to provide more direct proofs for process of melanosome transfer. METHODS: Human epidermal MCs and KCs were isolated and co-cultured with 1:10 ratio in a defined Keratinocyte-serum free medium (K-SFM). After exposure with 100 nM α-MSH or 20 μM PGE2 for 3 days, cells were fixed with 0.5% glutaraldehyde and AFM images of scanning observation were captured by contacting and tapping model under normal atmospheric pressure and temperature. RESULTS: It showed that human epidermal MCs in culture had secondary or tertiary branches. Except for globular granules structure on the surface of dendrites, some filopodia were protruded on the tips and lateral sides of the dendrites. The administration of α-MSH and PGE2 made not only the dendrites thinner and longer, but also the globular granules more intensive and denser. Many spheroid granules were shed from branches of dendrite and most of them adhered with dense filopodia. Compared with untreated group, the number of filopodia per cell, diameter of filopodia, and shedding spheroid granules per field all increased following α-MSH and PGE2 exposure (P<0.05, n=3). However, many crest-like protrusions, which were distributed homogenously on the surface of mono-cultured KCs, were less changed after α-MSH and PGE2 exposure. In co-culture model, α-MSH and PGE2 increased the number of transferred melanosomes in KCs under laser confocal microscopic examination. Filopodia were observed only on the adhesion area of KCs and MCs in a coiled style by AFM examination. In addition, the number of filopodia per field, diameter of filopodia and shedding spheroid granules per field all increased after the administration of α-MSH and PGE2 (P<0.05, n=3). CONCLUSIONS: Our data suggest that shedding spheroid granules, filopodia delivery and KC phagocytosis are major mode of melanosome transfer between MCs and KCs. PGE2, as well as α-MSH, drives melanosome transfer by promoting filopodia delivery and numbers of shedding spheroid granules in MCs, but no direct morphological effects on KCs. These findings open a new path in our understanding of MCs-KCs communication regulating pigmentation.
BACKGROUND:Skin pigmentation is accomplished by production of melanin in melanosome and by transfer of these organelles from melanocytes (MCs) to surrounding keratinocytes (KCs). However, the detailed mechanism is still unknown. OBJECTIVE: We aimed to investigate the morphological structure changes on human epidermal MCs and KCs, which were either mono-cultured or co-cultured, with or without the treatment of both α-Melanocyte-stimulating hormone (α-MSH) and prostaglandin E2 (PGE2), by atomic force microscopy (AFM) and to provide more direct proofs for process of melanosome transfer. METHODS:Human epidermal MCs and KCs were isolated and co-cultured with 1:10 ratio in a defined Keratinocyte-serum free medium (K-SFM). After exposure with 100 nM α-MSH or 20 μM PGE2 for 3 days, cells were fixed with 0.5% glutaraldehyde and AFM images of scanning observation were captured by contacting and tapping model under normal atmospheric pressure and temperature. RESULTS: It showed that human epidermal MCs in culture had secondary or tertiary branches. Except for globular granules structure on the surface of dendrites, some filopodia were protruded on the tips and lateral sides of the dendrites. The administration of α-MSH and PGE2 made not only the dendrites thinner and longer, but also the globular granules more intensive and denser. Many spheroid granules were shed from branches of dendrite and most of them adhered with dense filopodia. Compared with untreated group, the number of filopodia per cell, diameter of filopodia, and shedding spheroid granules per field all increased following α-MSH and PGE2 exposure (P<0.05, n=3). However, many crest-like protrusions, which were distributed homogenously on the surface of mono-cultured KCs, were less changed after α-MSH and PGE2 exposure. In co-culture model, α-MSH and PGE2 increased the number of transferred melanosomes in KCs under laser confocal microscopic examination. Filopodia were observed only on the adhesion area of KCs and MCs in a coiled style by AFM examination. In addition, the number of filopodia per field, diameter of filopodia and shedding spheroid granules per field all increased after the administration of α-MSH and PGE2 (P<0.05, n=3). CONCLUSIONS: Our data suggest that shedding spheroid granules, filopodia delivery and KC phagocytosis are major mode of melanosome transfer between MCs and KCs. PGE2, as well as α-MSH, drives melanosome transfer by promoting filopodia delivery and numbers of shedding spheroid granules in MCs, but no direct morphological effects on KCs. These findings open a new path in our understanding of MCs-KCs communication regulating pigmentation.
Authors: Christopher R Arnette; Quinn R Roth-Carter; Jennifer L Koetsier; Joshua A Broussard; Hope E Burks; Kathleen Cheng; Christine Amadi; Pedram Gerami; Jodi L Johnson; Kathleen J Green Journal: Pigment Cell Melanoma Res Date: 2019-10-10 Impact factor: 4.693
Authors: Hans Zoellner; Navid Paknejad; James A Cornwell; Belal Chami; Yevgeniy Romin; Vitaly Boyko; Sho Fujisawa; Elizabeth Kelly; Garry W Lynch; Glynn Rogers; Katia Manova; Malcolm A S Moore Journal: Biophys J Date: 2020-01-31 Impact factor: 4.033