Epidermal stem cells play an pivotal role in skin self-renewal, wound repair, and re-epithelialization process. The emergence of new technologies and concepts such as single-cell sequencing and gene knockout further revealed a new mechanism of epidermal stem cells in epidermal self-renewal and wound repair, providing new ideas for wound repair. In this review, the mechanisms of proliferation, differentiation, and migration of epidermal stem cells are discussed. Combined with the analysis of researches on stem cell heterogeneity and cell plasticity, the physiological function of epidermal stem cells can be further understood. The application advances of epidermal stem cells in wound repair is also summarized, which would provide some advice for workers engaged in clinical and basic research on wound repair.
Epidermal Cells/physiology* ; Epidermis ; Humans ; Re-Epithelialization ; Skin ; Soft Tissue Injuries ; Stem Cells

Epidermis ; Humans ; Hyperpigmentation ; Keratinocytes ; Particulate Matter/toxicity*

Objective: To investigate the effect of P62 on the migration and motility of human epidermal cell line HaCaT in high glucose microenvironment and its possible molecular mechanism, so as to explore the mechanism of refractory diabetic foot wound healing. Methods: The method of experimental research was used. HaCaT cells in logarithmic growth phase was taken for experiment. The cells were collected and divided into normal control group (culture solution containing glucose with final molarity of 5.5 mmol/L) and high glucose (culture solution containing glucose with final molarity of 30.0 mmol/L) 24 h group, high glucose 48 h group, and high glucose 72 h group according to the random number table (the same grouping method below). The cells in normal control group were routinely cultured for 72 h, cells in high glucose 72 h group were cultured with high glucose for 72 h, cells in high glucose 48 h group were routinely cultured for 24 h then cultured with high glucose for 48 h, cells in high glucose 24 h group were routinely cultured for 48 h then cultured with high glucose for 24 h. Then the protein expression of P62 was detected by Western blotting. The cells were collected and divided into normal control group and high glucose group. After being correspondingly cultured for 48 h as before, the protein expression of P62 was detected by immunofluorescence method (indicated as green fluorescence). The cells were collected and divided into negative control small interfering RNA (siRNA) group, P62-siRNA-1 group, P62-siRNA-2 group, and P62-siRNA-3 group, and transfected with the corresponding reagents. At post transfection hour (PTH) 72, the protein expression of P62 was detected by Western blotting. The cells were collected and divided into normal glucose+negative control siRNA group, normal glucose+P62-siRNA group, high glucose+negative control siRNA group, and high glucose+P62-siRNA group. After the corresponding treatment, the protein expression of P62 was detected by Western blotting at PTH 72 h, the cell migration rate was detected and calculated at 24 h after scratching by scratch test, with the number of samples being 9; and the range of cell movement was observed and the trajectory velocity was calculated within 3 h under the living cell workstation, with the number of samples being 76, 75, 80, and 79 in normal glucose+negative control siRNA group, normal glucose+P62-siRNA group, high glucose+negative control siRNA group, and high glucose+P62-siRNA group, respectively. The cells were collected and divided into normal glucose+phosphate buffered solution (PBS) group, high glucose+PBS group, and high glucose+N-acetylcysteine (NAC) group. After the corresponding treatment, the protein expression of P62 at 48 h of culture was detected by Western blotting and immunofluorescence method, respectively. Except for scratch test and cell motility experiment, the number of samples was all 3 in the rest experiments. Data were statistically analyzed with one-way analysis of variance and least significant difference test. Results: Compared with the protein expression in normal control group, the protein expressions of P62 of cells in high glucose 24 h group, high glucose 48 h group, and high glucose 72 h group were significantly increased (P<0.01). At 48 h of culture, the green fluorescence of P62 of cells in high glucose group was stronger than that in normal control group. At PTH 72, compared with the protein expression in negative control siRNA group, the protein expressions of P62 of cells in P62-siRNA-1 group, P62-siRNA-2 group, and P62-siRNA-3 group were significantly decreased (P<0.01). At PTH 72, compared with the protein expression in normal glucose+negative control siRNA group, the protein expression of P62 of cells in normal glucose+P62-siRNA group was significantly decreased (P<0.01), while the protein expression of P62 of cells in high glucose+negative control siRNA group was significantly increased (P<0.01); compared with the protein expression in high glucose+negative control siRNA group, the protein expression of P62 of cells in high glucose+P62-siRNA group was significantly decreased (P<0.01). At 24 h after scratching, compared with (55±7)% in normal glucose+negative control siRNA group, the cell migration rate in normal glucose+P62-siRNA group was significantly increased ((72±14)%, P<0.01), while the cell migration rate in high glucose+negative control siRNA group was significantly decreased ((37±7)%, P<0.01); compared with that in high glucose+negative control siRNA group, the cell migration rate in high glucose+P62-siRNA group was significantly increased ((54±10)%, P<0.01). Within 3 h of observation, the cell movement range in high glucose+negative control siRNA group was smaller than that in normal glucose+negative control siRNA group, while the cell movement range in normal glucose+P62-siRNA group was larger than that in normal glucose+negative control siRNA group, and the cell movement range in high glucose+P62-siRNA group was larger than that in high glucose+negative control siRNA group. Compared with that in normal glucose+negative control siRNA group, the cell trajectory speed in normal glucose+P62-siRNA group was significantly increased (P<0.01), while the cell trajectory speed in high glucose+negative control siRNA group was significantly decreased (P<0.01); compared with that in high glucose+negative control siRNA group, the cell trajectory speed in high glucose+P62-siRNA group was significantly increased (P<0.01). At 48 h of culture, compared with that in normal glucose+PBS group, the protein expression of P62 of cells in high glucose+PBS group was significantly increased (P<0.01); compared with that in high glucose+PBS group, the protein expression of P62 of cells in high glucose+NAC group was significantly decreased (P<0.01). At 48 h of culture, the green fluorescence of P62 of cells in high glucose+PBS group was stronger than that in normal glucose+PBS group, while the green fluorescence of P62 of cells in high glucose+NAC group was weaker than that in high glucose+PBS group. Conclusions: In HaCaT cells, high glucose microenvironment can promote the protein expression of P62; knockdown of P62 protein can promote the migration and increase the mobility of HaCaT cells; and the increase of reactive oxygen species in high glucose microenvironment may be the underlying mechanism for the increase of P62 expression.
Humans ; RNA, Small Interfering/genetics* ; Cell Line ; Epidermis ; Glucose/pharmacology* ; Epidermal Cells

Mannosylerythritol lipids (MELs) are glycolipids and have several pharmacological efficacies. MELs also show skin-moisturizing efficacy through a yet-unknown underlying mechanism. Aquaporin-3 (AQP3) is a membrane protein that contributes to the water homeostasis of the epidermis, and decreased AQP3 expression following ultraviolet (UV)-irradiation of the skin is associated with reduced skin moisture. No previous study has examined whether the skin-moisturizing effect of MELs might act through the modulation of AQP3 expression. Here, we report for the first time that MELs ameliorate the UVA-induced downregulation of AQP3 in cultured human epidermal keratinocytes (HaCaT keratinocytes). Our results revealed that UVA irradiation decreases AQP3 expression at the protein and messenger RNA (mRNA) levels, but that MEL treatment significantly ameliorated these effects. Our mitogen-activated protein kinase inhibitor analysis revealed that phosphorylation of c-Jun N-terminal kinase (JNK), but not extracellular signal-regulated kinase or p38, mediates UVA-induced AQP3 downregulation, and that MEL treatment significantly suppressed the UVA-induced phosphorylation of JNK. To explore a possible mechanism, we tested whether MELs could regulate the expression of peroxidase proliferator-activated receptor gamma (PPAR-γ), which acts as a potent transcription factor for AQP3 expression. Interestingly, UVA irradiation significantly inhibited the mRNA expression of PPAR-γ in HaCaT keratinocytes, whereas a JNK inhibitor and MELs significantly rescued this effect. Taken together, these findings suggest that MELs ameliorate UVA-induced AQP3 downregulation in HaCaT keratinocytes by suppressing JNK activation to block the decrease of PPAR-γ. Collectively, our findings suggest that MELs can be used as a potential ingredient that modulates AQP3 expression to improve skin moisturization following UVA irradiation-induced damage.
Down-Regulation* ; Epidermis ; Glycolipids ; Homeostasis ; Humans* ; JNK Mitogen-Activated Protein Kinases* ; Keratinocytes* ; Membrane Proteins ; Peroxidase ; Phosphorylation* ; Phosphotransferases ; PPAR gamma ; Protein Kinases ; RNA, Messenger ; Skin ; Transcription Factors ; Water

Anagen effluvium is an abrupt loss of hair in its growing phase due to an event that impairs the mitotic or metabolic activity of the hair follicle. Anagen effluvium is commonly associated with the administration of chemotherapy, radiation, and drugs as well as exposure to toxic chemicals. However, alopecia due to the administration of anti-tuberculosis drugs has rarely been reported in the literature. A 50-year-old female was diagnosed with intestinal tuberculosis and was started on anti-tuberculosis therapy with isoniazid, rifampicin, ethambutol, and pyrazinamide. After starting the treatment, erythematous to brown patches appeared all over her body, which was followed by diffuse hair loss on the scalp and body. Hair examination showed intact inner and outer root sheaths with fully pigmented hair bulbs, and histopathological examination of a scalp biopsy showed vacuolar degeneration in the interfollicular epidermis and perifollicular infiltration of mononuclear cells and eosinophils. The condition was diagnosed as anagen effluvium with drug eruption, and a potent corticosteroid lotion was prescribed for scalp application twice a day. After complete hair loss, the anti-tuberculosis medications were withdrawn, and hair regrowth started 4 months later. Here, we report a rare case of anagen effluvium with generalized drug eruption due to anti-tuberculosis medication.
Alopecia ; Biopsy ; Drug Eruptions* ; Drug Therapy ; Eosinophils ; Epidermis ; Ethambutol ; Female ; Hair ; Hair Follicle ; Humans ; Isoniazid ; Middle Aged ; Pyrazinamide ; Rifampin ; Scalp ; Tuberculosis

Patients with diabetes mellitus (DM) often suffer from diverse skin disorders, which might be attributable to skin barrier dysfunction. To explore the role of lipid alterations in the epidermis in DM skin disorders, we quantitated 49 lipids (34 ceramides, 14 free fatty acids (FFAs), and cholesterol) in the skin epidermis, liver, and kidneys of db/db mice, a Type 2 DM model, using UPLC-MS/MS. The expression of genes involved in lipid synthesis was also evaluated. With the full establishment of hyperglycemia at the age of 20 weeks, remarkable lipid enrichment was noted in the skin of the db/db mice, especially at the epidermis and subcutaneous fat bed. Prominent increases in the ceramides and FFAs (>3 fold) with short or medium chains (epidermis (16NS, 18NS, 24NS, 16NDS, 18NDS, 20NDS, 22NDS, 24NDS, C16:1FA, C18:2FA, and C18:1FA) and the liver (16NS, 18NS, 20NS, 24:1NS, 18NDS, 20NDS, 22NDS, C16:1FA, C18:2FA, C18:1FA), whereas those with very long chains were not affected. In the kidney, only slight increases (<3 fold) were observed for 16NS, 18NS, 20NS, 26NDS, C26FA, and C22:1FA. Consistently, LXRα/β and PPARγ, nuclear receptors promoting lipid synthesis, lipid synthesis enzymes such as elongases 1, 4, and 6, and fatty acid synthase and stearoyl-CoA desaturase were highly expressed in the skin and livers of the db/db mice. Collectively, our study demonstrates an extensive alteration in the skin and systemic lipid profiles of db/db mice, which could contribute to the development of skin disorders in DM.
Animals ; Ceramides ; Diabetes Mellitus ; Diabetes Mellitus, Type 2 ; Epidermis ; Fatty Acids, Nonesterified ; Humans ; Hyperglycemia ; Kidney ; Liver ; Mice ; Receptors, Cytoplasmic and Nuclear ; Skin ; Stearoyl-CoA Desaturase ; Subcutaneous Fat

Particulate matter (PM), which refers to the mixture of particles present in the air, can have harmful effects. Damage to cells by PM, including disruption of organelles and proteins, can trigger autophagy, and the relationship between autophagy and PM has been well studied. However, the cellular regulators of PM-induced autophagy have not been well characterized, especially in keratinocytes. The Aryl Hydrocarbon Receptor (AhR) is expressed in the epidermis and is activated by PM. In this study, we investigated the role of the AhR in PM-induced autophagy in HaCaT cells. Our results showed that PM led to AhR activation in keratinocytes. Activation of the AhR-target gene CYP1A1 by PM was reduced by co-treatment with α-naphthoflavone (α-NF), an AhR inhibitor. We also evaluated activation of the autophagy pathway in PM-treated keratinocytes. In HaCaT cells, treatment with PM treatment led to the induction of microtubules-associated proteins light chain 3 (LC3) and p62/SQSTM1, which are essential components of the autophagy pathway. To study the role of the AhR in mediating PM-induced autophagy, we treated cells with α-NF or used an siRNA against AhR. Expression of LC3-ІІ induced by PM was decreased in a dose dependent manner by α-NF. Furthermore, knockdown of AhR with siAhR diminished PM-induced expression of LC3-ІІ and p62. Together, these results suggest that inhibition of the AhR decreases PM-induced autophagy. We confirmed these results using the autophagy-inhibitors BAF and 3-MA. Taken together, our results indicate that exposure to PM induces autophagy via the AhR in HaCaT keratinocytes.
Autophagy ; Cytochrome P-450 CYP1A1 ; Epidermis ; Keratinocytes ; Negotiating ; Organelles ; Particulate Matter ; Receptors, Aryl Hydrocarbon ; RNA, Small Interfering

Rab25, a member of the Rab11 small GTPase family, is central to achieving cellular polarity in epithelial tissues. Rab25 is highly expressed in epithelial cells of various tissues including breast, vagina, cervix, the gastrointestinal tract, and skin. Rab25 plays key roles in tumorigenesis, mainly by regulating epithelial differentiation and proliferation. However, its role in skin physiology is relatively unknown. In this study, we demonstrated that Rab25 knock-out (KO) mice show a skin barrier dysfunction with high trans-epidermal water loss and low cutaneous hydration. To examine this observation, we investigated the histology and epidermal differentiation markers of the skin in Rab25 KO mice. Rab25 KO increased cell proliferation at the basal layer of epidermis, whereas the supra-basal layer remained unaffected. Ceramide, which is a critical lipid component for skin barrier function, was not altered by Rab25 KO in its distribution or amount, as determined by immunohistochemistry. Notably, levels of epidermal differentiation markers, including loricrin, involucrin, and keratins (5, 14, 1, and 10) increased prominently in Rab25 KO mice. In line with this, depletion of Rab25 with single hairpin RNA increased the expression of differentiation markers in a human keratinocyte cell line, HaCaT. Transcriptomic analysis of the skin revealed increased expression of genes associated with skin development, epidermal development, and keratinocyte differentiation in Rab25 KO mice. Collectively, these results suggested that Rab25 is involved in the regulation of epidermal differentiation and proliferation.
Animals ; Antigens, Differentiation ; Breast ; Carcinogenesis ; Cell Line ; Cell Proliferation ; Cervix Uteri ; Epidermis ; Epithelial Cells ; Female ; Gastrointestinal Tract ; GTP Phosphohydrolases ; Humans ; Immunohistochemistry ; Keratinocytes ; Mice ; RNA ; Skin Physiological Phenomena ; Skin ; Vagina ; Water

A 40-year-old man presented with pruritic, multiple, variable-sized, erythematous umbilicated papules on the trunk and both extremities for 4 months. He was diagnosed with Hodgkin's lymphoma (stage IIA) after histopathologic examination of a neck mass that developed a month ago. A punch biopsy was performed on his right lower leg. Histological examination showed transepidermal elimination of the degenerated collagen. Masson's trichrome staining was performed to distinguish collagen fibers from the muscular tissue; using Masson's stain, the collagen appeared as a bluish color crossing from the dermis to the epidermis. The diagnosis of acquired reactive perforating collagenosis was made. The skin lesions showed much improvement after 6 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy. Acquired perforating disorders are a group of cutaneous disorders that occur in adults with chronic kidney disease or diabetes mellitus. Cases of acquired perforating disorders associated with Hodgkin's lymphoma have been rarely reported in the English literature. To our knowledge, this is the first case of acquired reactive perforating collagenosis in a Korean patient with Hodgkin's lymphoma.
Adult ; Biopsy ; Bleomycin ; Collagen ; Dacarbazine ; Dermis ; Diabetes Mellitus ; Diagnosis ; Doxorubicin ; Drug Therapy ; Epidermis ; Extremities ; Hodgkin Disease ; Humans ; Leg ; Neck ; Renal Insufficiency, Chronic ; Skin ; Vinblastine

Immunoglobulin A (IgA) pemphigus is a rare variant of an autoimmune bullous disease with IgA antibodies. IgA pemphigus is divided into 2 major subtypes: the subcorneal pustular dermatosis (SPD) type and intraepidermal neutrophilic (IEN) dermatosis type. We documented a case of an 18-year-old woman with recurrent generalized blisters and pustules that were especially severe in the intertriginous areas. Some half-and-half blisters and coalesced pustules in an annular pattern with crusts were simultaneously observed. A biopsy specimen from one of the half-and-half blister lesions showed intraepidermal separation with multiple neutrophils. Direct immunofluorescence staining revealed lace-like intercellular deposition of IgA in the entire epidermis. IgA antibody deposits were also observed in the patient's serum. The eruptions cleared with systemic steroids and colchicine 0.6 mg for 1 week, and the patient remained in partial remission at the 8-month follow-up. Herein, we report a case of IEN-type IgA pemphigus, clinically mimicking SPD with half-and-half blisters.
Adolescent ; Antibodies ; Biopsy ; Blister ; Colchicine ; Epidermis ; Female ; Fluorescent Antibody Technique, Direct ; Follow-Up Studies ; Humans ; Immunoglobulin A ; Immunoglobulins ; Neutrophils ; Pemphigus ; Skin Diseases ; Skin Diseases, Vesiculobullous ; Steroids