ABSTRACT
The epidermis, the outermost layer of the skin, is the first barrier that comes into contact with the external environment. It plays an important role in resisting the invasion of harmful substances and microbial infections. The skin changes with age and external environmental factors. This study aimed to investigate epidermal stem cells during the process of aging. This study enrolled 9 volunteers with benign pigmented nevus for clinical dermatologic surgery. The phenotypes associated with skin aging changes such as skin wrinkles and elasticity of the unexposed/healthy parts near benign pigmented skin were measured, and epidermal stem cells from this region were isolated for transcriptome sequencing. The results showed that epidermal stem cells could be obtained by magnetic activated cell sorting (MACS) with high purity. Results of the transcriptome sequencing revealed that aquaporin (AQP)5 significantly decreased in the epidermal stem cells with age, and further functional experiments revealed that AQP5 could promote the proliferation and dedifferentiation of HaCaT, but did not influence cell apoptosis. In summary, AQP5 regulated the proliferation and differentiation of epidermal stem cells in skin aging, and it may play an important role in the balance of proliferation and differentiation. However, further studies are needed to determine the mechanism by which AQP5 regulates the proliferation and differentiation of epidermal skin cells in aging.
Subject(s)
Humans , Skin Aging , Aquaporin 5/metabolism , Stem Cells , Cell Differentiation , Cell Proliferation , EpidermisABSTRACT
Objective To investigate the influencing conditions of human epidermal stem cells(ESCs) differentiating into gland-like cells and to identify the induced tubular structure.Methods The ESCs were seeded onto compound polysaccharide shell dermal matrix and collagen gel,adding different concentrations of epidermal growth factor(EGF) and culturing by vertical shaking in vitro,the three dimensional culture and induced directional differentiation were performed.The means of HE staining,immunofluorescence and confocal laser scanning microscope were adopted to observe the conditions,morphology and phenotype change of ESCs directionally differentiating into glandular epithelium-like cells.Results 15-20 ng/mL EGF could induce ESCs in tissue-engineering dermis to grow into dermis and appear the gland-like structure.The HE staining in this structure showed its profile as a single layer with lacune in the middle compartment,eosinophilic cytoplasm,lightly stained.Under CLSM,by CK19 staining,the luminal structure in the middle of the cell mass was observed,while CK18 and CEA were expressed in this structure.Conclusion Under the induction of particular concentration of EGF,the in vitro cultured human ESCs seeded on the tissues engineering dermis could form into the tubular structure,which is similar to the in vivo sweat gland secretory cells in morphology and histology.
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The epidermal stem cell was introduced briefly in this review.And then the spacial characteristics of diabetic wound healing were summarized.In this regards,we focus on the important role of epidermal stem cell in diabetic wound healing.At last,we outlook the research direction and clinical application of epidermal stem cell in diabetic wound.
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Objective To establish a simple and reliable method for isolation and cultivation of epidermal stem cells from neo-natal rat skin basal layer .Methods The single cells were dissociated with twice trypsinization form neonatal rat skin .Thereafter we purified the basal layer stem cells with differential velocity adherent technique with collagen Ⅳ ,and the slow adherent cells were cultured as negative control cells .Both basal layer stem cells and control cells were cultivated with keratinocyte serum-free medium (K-sfm) .Stem cells were identified with β1-integrin and Keratin 19 by co-immunofluorescence assay ,and colony forming assay was executed to evaluate the proliferation potential of stem cells .Results The polygonal cells grew like flagstones ,with doubling time of approximately 24 hours .Both the morphology and growth properties of cells were in accordance with the character of basal layer stem cells .Co-immunofluorescence identification showed the cells were positive for the expression of β1-integrin and Keratin 19 . Basal layer stem cells had stronger clone forming ability in vitro compare with control group .Conclusion The results indicate that two-procedure trypsinization plus differential velocity adhesion is an ideal method for basal layer stem cells separation followed with vigorous vitality and reliable phenotype .
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Objective To explore a method for isolation and culture of human epidermal stem cells. Methods Epidermis was obtained by digesting human foreskin with Dispase Ⅱ and Trypsin-EDTA.After suspension on the epidermal stem cell medium (ESCM), these single epidermis cells were inoculated onto human collagen Ⅳ-coated flasks and cultured at 37 ℃ in a humidified atmosphere containing 5% CO_2 for 10 min. The nonadherent cells were rinsed off 10 min after inoculation, and the adherent cells continued to be cultured after enriching and abstraction by type Ⅳ collagen. The cell growth was observed through inverted microscope, and the cell cloning efficiency and time of clone sustain were also detected. Immunocytochemistry was used to observe the expression of ?_1-integrin and keratin 19(K19). Keratinocytes were served as controls. Results It was revealed by histological observation that colonies were formed 24 hours after inoculation. The isolated and cultured cell cloning efficiency was higher and the time of clone sustain was longer than that of the control group. Positive expression of ?_1-integrin and K19 of cultured cells was detected by immunocytochemistry. Conclusion Adult epidermal stem cells could be successfully isolated and cultured by adhension with type Ⅳ collagen and culture with ESCM.
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Objective To investigated the distribution of epidermal stem cells in rat full-thickness wound tissues during the wound healing process and to elucidate the roles of epidermal stem cells in wound repair in vivo. Methods Eighty circular full-thickness wounds were produced on both sides of the back in 20 male Wistar rats labeled with BrdU 60 days previously (4 wounds in each rat). BrdU, β1 integrin and keratin 19 (K19) were employed to determine the epidermal stem cells with SP immunohistochemical methods, and the epithelialization was determined with routine histological methods of HE staining on the 3rd, 7th, 14th, and 21st days after operation. Results No cells with positive immunostaining for β1 integrin, K19 and BrdU were found in granulation tissue of wound in both groups during the healing process. However, a few scattered β1 integrin and K19 positive cells were found within the stratum spinosum and stratum granulosum of the epidermis on the wound edges on the 3rd day post-injury. And these positive cells gradually became more and more in number, and mostly concentrated on the border of wound edges till the wounds healed. In addition, the number of positive cells for β1 integrin and K19 in the infected wounds was less than that in non-infected wounds. These positive cells for β1 integrin and K19 staining on the wound edge were also positively stained with BrdU in the cellular nuclei. Conclusion The above results indicate that ectopia of epidermal stem cells present a major function during wound epithelialization.
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Objective To study the expression characteristics of cytokeratin 19(CK19) in different live tissues from victims with third-degree burns to explore the possible mechanisms of tissue reparation and regeneration in orthophoria.Methods 10 young victims with third-degree burns were included in this study.Alive tissues at different regeneration stages were studied by immunohistochemistry with streptavidin-biotin-peroxidase method using specific anti-CK19 monoclonal antibody. Only cytoplasm expression was considered as specific.Normal skin tissue and chronic skin ulcer were used as controls.The study was focused on the distribution and morphological features of CK19-positive cells.Results ⑴In normal skin ,CK19-positive cells were seen in basialis layer of epiderm and cutaneous appendages.⑵CK19-positive cells were not found in subcutaneous tissue at 3～6 days after the injury,but they were seen in granulation tissues.⑶A lot of CK19-positive cells were detected in early regeneration tissues.⑷In late regeneration tissues,CK19-positive cells were detected in basialis layer of epiderm and cutaneous appendages.⑸Advanced regenerationed epidermal tissue was similar to that of normal.⑹No CK19-positive cells were observed in all of 6 cases with chronic skin ulcer.Conclusion It is possible that victims with third-degree burns could be healed by tissue regeneration orthophoria.
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To investigate the distribution of epidermal stem cells in regenerating wound tissues, and to elucidate the role of epidermal stem cells during wound repair. 80 circular full-thickness wounds were produced on both sides of the back in 20 male Wistar rats labeled 60 days previously with 5-Bromodeoxyuridine (BrdU) (4 wounds in each animal). Then these 80 wounds were randomly divided into 2 groups as follows: group A: with topical treatment of epidermal growth factor (n=40) and group B: no-treatment (n=40). BrdU, ? 1 integrin and keratin19 (K19) were employed to determine the epidermal stem cells with streptavidin-peroxidase (SP)immunohistochemical method, and the speed and quality of epithelialization were determined with routine histological methods with HE staining on the 3rd, 7th, 14th, and 21st day after the wounding. Results showed that the healing rate of wounds was 80% in group A (32/40) and 60% in group B (24/40). No cells with positive immunostaining for BrdU, ? 1 integrin, or K19 were found in the granulation tissue of all wounds in both groups during the healing process. However, a few BrdU, ? 1 integrin and K19 positive cells, bearing no anatomic relation with the epidermal stem cells in the basal layer, were found scattering in the stratum spinosum and stratum granulosum of the epidermis on the wound edges. The results suggested that epidermal stem cells appearing on the wound edges were the main source of re-epithelialization of granulating wounds.
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Objective To investigate the condition which can induce mouse ES cells to differentiate into epidermal-like stem cells for the clinical application of ES cells-derived epidermal-like stem cells and the research on the mechanism of committed differentiation of ES cells. Methods Coculture mouse ES cells with human amnion for 3-4 days, and the committed differentiation were detected by flow cytometry and immunohistochemistry. In experimental group 1, amnion was pasted covering the whole bottom of the wells, with the epithelial surface upward, and in group 2 covering the half bottom. No amnion was used in control. Results After 3-4 days of co-culture, epidermal-like stem cell clones were formed on the epithelial surface of amnion in group 1 and group 2, and expressed high levels of integrin-? 1, CK19 and CK15. The percentages of integrin-? 1, CK19 and CK15 positive cells counted in group 1 by flow cytometry were 89.2%, 86.8% and 71.2% respectively, versus the control group of 8.4%,9.6% and 11.8%, the differences were significant in all the three indices (Z tests P