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Skin wound healing involves Notch/Jagged1 signaling. However, little is known how Jag1 expression level in epidermal stem cells (ESCs) contributes to wound healing and scar formation. We applied multiple cellular and molecular techniques to examine how Jag1 expression in ESCs modulates ESCs differentiation to myofibroblasts (MFB) in vitro, interpret how Jag1 expression in ESCs is involved in wound healing and scar formation in mice, and evaluate the effects of porcine acellular dermal matrix (ADM) treatment on wound healing and scar formation. We found that Jag1, Notch1 and Hes1 expression was up-regulated in the wound tissue during the period of wound healing. Furthermore, Jag1 expression level in the ESCs was positively associated with the level of differentiation to MFB. ESC-specific knockout of Jag1 delayed wound healing and promoted scar formation in vivo. In addition, we reported that porcine ADM treatment after skin incision could accelerate wound closure and reduce scar formation in vivo. This effect was associated with decreased expression of MFB markers, including α-SMA Col-1 and Col-III in wound tissues. Finally, we confirmed that porcine ADM treatment could increase Jag1, Notch1 and Hesl expression in wound tissues. Taken together, our results suggested that ESC-specific Jag1 expression levels are critical for wound healing and scar formation, and porcine ADM treatment would be beneficial in promoting wound healing and preventing scar formation by enhancing Notch/Jagged1 signaling pathway in ESCs.

Epidermal growth factor (EGF)-like family members mediate a wide range of biological activities including cell proliferation and migration. Increasing evidence indicated that EGF plays an important role in the process of wound healing by stimulating fibroblast motility. The aim of this study was to see whether EGF-like domain 7 (EGFL7)-overexpressing epidermal stem cells (EGFL7-ESCs) would promote fibroblast proliferation and migration. We found that mRNA and protein levels of EGFL7 expression were significantly increased in EGFL7-ESCs. The protein expression of EGFL7 was significantly elevated in conditioned media (CM) of EGFL7-ESCs compared to ESCs CM or vector-ESCs CM. The cell count and cell viability of EGFL7-ESCs CM-treated fibroblasts were also significantly increased compared to control. In addition, EGFL7-ESCs CM-treated fibroblasts showed elevated migration compared with control. Moreover, the expressions of β1-integrin, β-tubulin, β-actin, and Vimentin were increased, while that of E-cadherin was decreased in EGFL7-ESCs CM-treated fibroblasts. These results indicate that EGFL7-ESCs contribute towards promoting fibroblast migration through enhancing cell adhesion, strengthening cytoskeleton, and reducing intercellular aggregation. These findings suggest that the stimulating effect of EGFL7-ESCs on fibroblast proliferation and migration may provide a useful strategy for wound healing.

Chronic, non-healing wounds are a major complication of diabetes. Recently, various cell therapies have been reported for promotion of diabetic wound healing. Epidermal stem cells (ESCs) are considered a powerful tool for tissue therapy. However, the effect and the mechanism of the therapeutic properties of ESCs in the diabetic wound healing are unclear. Herein, to determine the ability of ESCs to diabetic wound healing, a dorsal skin defect in a streptozotocin (STZ)-induced diabetes mellitus (DM) mouse model was used. ESCs were isolated from mouse skin. We found that both the mRNA and protein levels of a Notch ligand Jagged1 (Jag1), Notch1 and Notch target gene Hairy Enhancer of Split-1 (Hes1) were significantly increased at the wound margins. In addition, we observed that Jag1 was high expressed in ESCs. Overexpression of Jag1 promotes ESCs migration, whereas knockdown Jag1 resulted in a significant reduction in ESCs migration in vitro Importantly, Jag1 overexpression improves diabetic wound healing in vivo These results provide evidence that ESCs accelerate diabetic wound healing via the Notch signalling pathway, and provide a promising potential for activation of the Notch pathway for the treatment of diabetic wound., (© 2016 The Author(s).)

Skin-derived precursors (SKPs), which are located at skin's dermis, display multi-lineage potential and can produce both neural and mesodermal progeny in vitro. SKPs are considered to take part in dermal reconstruction and may be an important source of fibroblast during wound repairing. To explore the possibility of differentiation of SKPs into fibroblasts, the 3(rd) passage SKPs were treated with 0, 20, 40, 100, or 500 ng/ml human recombinant connective tissue growth factor (CTGF) for 48 h or treated with 100 ng/ml CTGF for 0, 24, 48, 72, or 96 h. Subsequently, a series of methods were to be used to observe cells immunocytochemistry changes under fluorescence microscope, to validate the mRNA expression change of collagen I, collagen III, fibroblast-specific protein 1 (FSP-1) and alpha smooth muscle actin (α-SMA) by quantitative real-time reverse transcriptase polymerase chain reaction (QRT-PCR), to analyze the expression of collagen I and collagen III protein by Enzyme-linked immunosorbent assay (ELISA), to semiquantitatively measure the expression of FSP-1 and α-SMA by western-blot. After differentiation, cells showed that positively staining for collagen I, collagen III, α-SMA, and FSP-1, which are markers for fibroblasts, but negative expression for neural precursors. The effects of CTGF on collagen I, collagen III, FSP-1 and α-SMA in SKPs were detected both on the transcriptional and posttranscriptional levels. These findings indicate that SKPs can be induced to differentiate into fibroblast-like cells with CTGF treatment that may be a key source of fibroblast in wound healing.

The management of burns and injuries using novel treatment strategies involving epidermal stem cells (ESC) requires a better understanding of the biology of these cells, in particular, their isolation and the maintenance of their unique characteristics in culture. The purpose of this study was to describe an improved method for isolating putative ESC from fetal rat skin and to maintain them long term in culture. Single ESC suspensions were obtained from fetal rat skin by enzyme digestion containing 0.5% neutral protease. The target cells were harvested by rapid adherence on type IV collagen plates and were cultured in complex DMEM. After primary isolation, cells were continuously cultured in K-serum free medium. After reaching 70-80% confluence, the cells were digested with 0.25% trypsin at 37°C for 5-10 minutes, and passaged at a ratio of 1:2. The cultured ESC showed good growth, resulting in cell viability of over 98%. Four days later, clones containing 100-200 cells were detected, showing cobblestone-like characteristics. The rapidly adherent cells were positive for keratin 15, 19 and P63. Eighty three percent of cells expressed β1 integrin. The growth-curve showed that the rapidly adherent cells were in the exponential growth phase. The protocol described in this paper provides a simplified and effective method to isolate and maintain long-term culture of epidermal stem cells from fetal rat skin. This method should be valuable for isolating and studying ESC from various transgenic rat lines that are currently available.

Objective: To study the effect of skin-derived progenitor cell (SKP) combined with hyaluronic acid( HA) on the wound healing in diabetic rats., Methods: SKP of Spraque-Dawley (SD) neonate rats were isolated and cultured and mixed with HA. The differentiation characteristics of SKP in the culture were observed. Sixty SD rats were injected intraperitoneally with 65 mg/kg streptozotocin( STZ) to induce diabetes. Two symmetrical full-thickness cutaneous wounds( 1.0 cm in diameter) were made on the back of each SD rat and randomly divided into A (n = 20, with treatment of 100 mircol SKP-HA) , B (n = 20, with treatment of 100 mirol HA) , and C ( n = 20, with treatment of DMEM/F12 culture medium) groups. Tissue samples from wound in each group were harvested on 1, 2, 3, 4 weeks after the treatment. Wound healing rate, changes in histomorphology, the content of hydroxyproline ( HYP) , and immigration of labelled SKP were determined and analyzed., Results: SKP grew well when cultured with HA. The characteristics of SKP to differentiate into lipocyte, neuron, and neurogliocyte remained in the culture. Compared with that in C group, epithelization in the wounds of A and B groups appeared earlier. The wound healing rate in A group [ (72.1 +/- 2. 8)% ] and B group [ (53.7 +/- 2. 9)% ] were obviously higher at 2 post-treatment weeks(PTW) than that in group C [(42. 5 +/- 1.5)% ( P <0.05) , and that in A group was obviously higher compared with B and C groups at 3 PTW ( P < 0. 05 or 0. 01). The wound healing rates in A and B groups were (100. 00 +/- 0.00) % at 4 PIW, which were obviously higher than that of group C( P <0.01) . There was no obvious difference in the HYP content among the 3 groups at 1 PIW ( P > 0. 05) , but it was obviously higher in A and B groups than that in C group at 2,3,4 PTW( P <0.01) , and that in A group was significantly higher than that in B group at 3 and 4 PTW( P <0. 01). SKP survived well on the wound, and migrated towards the dermis as time elapses., Conclusion: SKP-HA composition can promote wound healing in diabetic rats.

Objective: To investigate the regular pattern of the distribution of skin epidermal stem cells (ESCs) in the different parts of a healthy human body, and to evaluate the feasibility of the identification of ESCs by P63 and CD29 with single and double labeling., Methods: Full-thickness skin samples from 21 parts (including scalp, dorsum of foot, sole of foot, pubic region, and scrotum) of 5 healthy persons were harvested for the study. Immunohistochemistry method with biotin-streptavidin-horseradish peroxidase (SP) was employed with P63 and CD29 as the first antibody to carry out single and double labeling. The staining results were subjected to image analysis. The distribution of the ESCs in the skin from the above parts was observed and expressed as positive unit (PU) value., Results: It was found by P63 single labeling and P63 and CD29 double labeling that the PU value in the dorsum of foot was the lowest while that in the scalp was the highest among all the parts of a healthy body. It was also found by CD29 single labeling that the PU value in the dorsum of foot was the lowest [(11.9 +/- 1.5)%] while highest in the scalp [(29.1 +/- 5.0)%]. The PU value in the hairy region of a human body was evidently higher than that in the non-hairy region (P < 0.01), when examined by P63 and CD29 single and double labeling. But there was no difference in the PU values between the trunk and limbs by means of P63 and CD29 single and double labeling (P > 0.05)., Conclusion: There are more ESCs in the skin from the scalp, mons pubis and scrotum than other parts of the body. Single P63 or CD29 labeling exhibits higher sensitivity but lower specificity in the identification of ESCs. While the double labeling method exhibits higher specificity but lower sensitivity. Above all, it seems that the double labeling may be a simple and effective method for the identification of ESCs.

Objective: To investigate the distribution of epidermal stem cells (ESCs) in different degrees of burn wounds in scalded rats., Methods: Thirty-two Sprague-Dawley (SD) rats were employed in the study. First degree (I), shallow (shallow II) and deep partial thickness (deep II) and full thickness burn wounds (III) were created on the rat skin. Burn wound samples were harvested at 24 postburn hours (PBHs) from all the wounds and were processed to tissue slices. The tissue slices were stained by immunohistochemistry technique. The expression and distribution of ESCs in different degrees of burn wounds were observed with integrins alpha 2 beta 1 and keratin 10 (K10) as first antibodies., Results: K10 positive cells were found to distribute in the strata spinosum, granulosum and lucidum in the first degree burn wound (I) with large amounts of integrins alpha 2 beta 1 positive cells in the residual basal layer and skin appendages (hair follicles) in shallow partial thickness burn wound (shallow II degree), and there were less integrins alpha 2 beta 1 positive cells in the remaining skin appendages in deep dermis in deep partial thickness burn wound (deep II degree). Finally, integrins alpha 2 beta 1 positive cells were sparsely found in the III degree burn wound., Conclusion: The distribution of ESCs in burn wounds was closely related to the depth of burn wound. The residual ESCs might be the origin of burn wound regeneration and reepithelization.