Tranexamic Acid Ameliorates Skin Hyperpigmentation by Downregulating Endothelin-1 Expression in Dermal Microvascular Endothelial Cells.

BACKGROUND: Although reports suggest that tranexamic acid (TXA) has clinical benefits for melasma patients by oral, intralesional and topical treatment, the optimal route of TXA therapy and the underlying mechanism involved remain poorly defined. OBJECTIVE: To compare the skin lightening effect between oral TXA and topical TXA and to dissect the molecular mechanisms using ultraviolet B (UVB)-induced hyperpigmentation mouse model, ex vivo cultured human skin explant, and cultured melanocytes (MCs) and endothelial cells. METHODS: Melanin content and cluster of differentiation 31 (CD31)-positive cell numbers were measured in tail skins from UVB-irradiated mice treated by intragastral or topical TXA using immunofluorescent and Fontana-Masson staining. The conditioned medium (CM) was harvested from human umbilical vein endothelial cells treated with or without 3 mM TXA and was used to treat MCs for 48 hours. mRNA and protein levels of tyrosinase and microphthalmia-associated transcription factor were measured using quantitative real-time reverse transcription polymerase chain reaction and western blotting assays. HMB45- and CD31-positive cell numbers as well as melanin content were also examined in ex vivo cultured human skin explants. RESULTS: The hyperpigmented phenotype were significantly mitigated in UVB-irradiated tail skin plus intragastral TXA-treated mice compared with mice treated with UVB only or with UVB plus topical TXA. CD31-positive cell numbers correlated with the anti-melanogenic activity of TXA therapy. The data from cultured cells and skin tissues showed that suppression of endothelin-1 (ET-1) in vascular endothelial cells by TXA reduced melanogenesis and MC proliferation. CONCLUSION: Oral TXA outperforms topical TXA treatment in skin lightening, which contributes to suppression of ET-1 in dermal microvascular endothelial cells by TXA.

Effect of topical 5-aminolevulinic acid-mediated photodynamic therapy combined with CO2 laser pretreatment for vaginal condyloma acuminate.

BACKGROUND: Condyloma acuminatum (CA) of the vagina is a sexually transmitted disease due to infection by human papilloma virus (HPV). The treatment efficacy of the conventional methods for vaginal CA is often unsatisfactory with a high recurrence rate. Topical 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) combined with CO2 laser pretreatment is a feasible approach for vaginal CA, but the effectiveness and safety need further evaluation. METHODS: This study enrolled 15 patients with vaginal CA. All patients underwent CO2 laser ablation and then ALA-PDT for two or three cycles. The clinical efficacy and side effects were evaluated and analyzed during the treatment and 6 months after the treatment. RESULTS: The wart lesions in 4 cases (26.7 %) disappeared after the first treatment. The wart lesions in 5 cases (33.3 %) disappeared after the second treatment. And 6 cases (40 %) needed three treatment cycles before the lesions disappeared completely. The complete response (CR) rate was 93.3 % (14/15) at 2 weeks after three treatment cycles. There were 5 cases (83.3 %) which have complete remission after 2 treatments in warts diameter <1 cm group. There were only 4 cases (44.4 %) which have complete remission after 2 treatments in diameter>1 cm group. All patients had CR without reoccurrence at 6 months after treatment. The side effects mainly included a mild or moderate burning or stinging sensation (26.7 %). There were no infection, ulcers and scars after treatment. CONCLUSION: Topical 5-aminolevulinic acid-mediated photodynamic therapy combined with CO2 laser pretreatment is a safe and effective treatment for vaginal CA.

A multicenter, randomized, double-blinded, placebo-controlled, phase â ¢ study evaluating the efficacy and safety of Xeligekimab (GR1501) in patients with moderate-to-severe plaque psoriasis.

BACKGROUND: Xeligekimab is a fully human monoclonal antibody that selectively neutralizes IL-17A and had shown potential efficacy in preliminary trials. OBJECTIVE: To evaluate the efficacy and safety of Xeligekimab in Chinese patients with moderate-to-severe psoriasis. METHODS: A total of 420 Chinese patients were randomized to 200 mg Xeligekimab every 2 weeks (n = 281) or placebo (n = 139) for the first 12 weeks, followed by extending the treatment schedule to GR1501 every 4 weeks for further 40 weeks. Efficacy was assessed by evaluating the Physician's Global Assessment (PGA) 0/1 and Psoriasis Area and Severity Index (PASI) 75/90/100 improvement. The safety profile was also evaluated. RESULTS: At week 12, The PASI 75/90/100 were achieved in 90.7%/74.4%/30.2%% patients in GR1501 group compared with 8.6%/1.4%/0% patients in placebo group, respectively. The PGA 0/1 were achieved in 74.4% patients of GR1501 group and 3.6% patients in placebo group, respectively. The PASI 75 and PGA 0/1 maintained until week 52. No unexpected adverse events were observed. CONCLUSION: Xeligekimab showed high efficacy and is well tolerated in Chinese patients with moderate-to-severe plaque psoriasis.

Acceleration of melanocyte senescence by the proinflammatory cytokines IFNγ and TNFα impairs the repigmentation response of vitiligo patients to narrowband ultraviolet B (NBUVB) phototherapy.

Vitiligo is a chronic autoimmune disease characterized by the T helper 1 (Th1) cytokine-driven immune destruction of melanocytes (MCs). Although narrowband ultraviolet B (NBUVB) phototherapy has been proven to be an effective therapeutic option, the repigmentation response to that phototherapy varies greatly in different vitiligo patients. Here, we demonstrate that there is an increase of NBUVB-induced cellular senescence in vitiligo MCs exposed to Th1 cytokine interferon γ (IFNγ) and/or tumor necrosis factor α (TNFα) in lesional vitiligo skin from poor responders who had undergone NBUVB phototherapy. Supplementation with exogenous recombinant human stem cell factor (rhSCF) in the culture medium as well as the lentiviral vector-mediated overexpression of cKIT could prevent the MCs from the IFNγ/TNFα-accelerated cellular senescence. Mechanistic studies indicated that the reduced ratio of membrane-bound KIT (mKIT) to the soluble form of KIT (sKIT) is directly related to the cellular senescence of vitiligo MCs following exposure to IFNγ and TNFα. Furthermore, the matrix metalloprotease 9 (MMP9) inhibitor GM6001 attenuates the production of sKIT via the suppression of cKIT ectodomain shedding. Altogether, our study indicates that the presence of Th1 cytokines IFNγ and/or TNFα in the epidermal milieu might impair the repigmentation response of vitiligo patients to NBUVB phototherapy.

Uncoupling melanogenesis from proliferation in epidermal melanocytes responding to stimulation with psoriasis-related proinflammatory cytokines.

BACKGROUND: Few studies have addressed the impact of the psoriasis-related proinflammatory cytokines on the proliferation and melanogenesis of melanocytes (MCs) in lesional psoriatic skin. OBJECTIVE: We investigated the effects of TNFα, IL17A, and IL8 on the proliferation and melanin synthesis of MCs. METHODS: Skin specimens were biopsied from patients with psoriasis vulgaris at the active stage, or from the tail skin of Dct-LacZ mice with imiquimod (IMQ)-induced psoriasiform dermatitis. Cultured keratinocytes (KCs), MCs, and human skin explants were used in this study. The numbers of MCs were measured via ß-galactosidase staining, EdU incorporation and HMB45 immunohistochemical staining. The expression of human ß-defensin 3 (hBD3) in KCs was silenced by siRNA, the conditioned medium (CM) from siRNA-transfected KCs was used to treat MCs, then followed by αMSH stimulation. The melanogenesis-related genes were examined by using qRT-PCR and western blotting. RESULTS: The increased number of MCs and decreased melanin content were highly relevant to the enhanced expression of IL8 and BD3 both in human psoriatic skin and in IMQ-treated mouse tail skin. IL8 expression in KCs and CXCR2 expression in MCs was significantly increased by IL17A and TNFα, the αMSH-induced upregulations of microphthalmia-associated transcription factor (MITF) and tyrosinase in MCs were abrogated by the CM from hBD3-unsilenced KCs, but not from hBD3-silenced KCs. CONCLUSION: Our results suggest the roles of IL8-CXCR2 activation in promoting MC proliferation and of BD3 upregulation in reducing melanogenesis. These findings have been implicated in the underlying mechanism that active psoriasis prefers hypopigmentation despite chronic inflammation.

sPmel17 Secreted by Ultraviolet B-Exposed Melanocytes Alters the Intercellular Adhesion of Keratinocytes.

Repigmentation of the skin in patients with vitiligo represents an intricate process in which the depigmented epidermis is replenished by functional melanocytes (MCs) that migrate from undamaged hair follicles and/or surrounding areas. We characterized whether MCs release a secreted form of Pmel17 (sPmel17) protein after exposure to UVB, thereby weakening the cell-cell adhesions of keratinocytes (KCs), which provides MCs the opportunity to migrate to areas devoid of MCs. At first, we examined the interactions of sPmel17 and FHL2 (four-and-a-half LIM domain protein 2) in KCs treated with the conditioned media (CM) from MCs exposed to UVB. The results showed that both the protein and mRNA levels of FHL2 were significantly upregulated in KCs treated with sPmel17-enriched CM from UVB-exposed MCs. We also found that there are physical interactions between sPmel17 and FHL2 as analyzed by reciprocal coimmunoprecipitation assays and double immunofluorescence staining. The CM from UVB-exposed MCs signaled KCs to remodel the actin cytoskeleton and reduce E-cadherin expression. However, the CM from UVB-exposed and Pmel17-silenced or from UVB-unexposed MCs failed to do this. To further determine the in situ distributions of sPmel17, FHL2, and E-cadherin, we examined the expression profiles of those proteins in the skin from healthy subjects and from depigmented or repigmented vitiligo using immunofluorescence and immunohistochemical staining. The results showed that the expression of sPmel17 was positively correlated with FHL2 but not to E-cadherin. The colocalization of FHL2 and sPmel17 was also observed in UVB-exposed mouse tail skin. Together, the upregulation of FHL2 in KCs requires stimulation by sPmel17 secreted from MCs and activation of the sPmel17-FHL2-E-cadherin axis offers a potential therapeutic target to expedite the repigmentation process in patients with vitiligo.

A multicenter, randomized, double-blinded, placebo-controlled, dose-ranging study evaluating the efficacy and safety of vunakizumab in patients with moderate-to-severe plaque psoriasis.

BACKGROUND: Vunakizumab (SHR-1314) is a novel interleukin 17A monoclonal antibody that has shown preliminary efficacy and tolerability in phase I trials. OBJECTIVE: To evaluate the efficacy and safety of vunakizumab in moderate-to-severe plaque psoriasis. METHODS: In this 36-week, multicenter, double-blinded, phase II study (NCT03463187), 187 eligible patients with moderate-to-severe plaque psoriasis were randomized 1:1:1:1:1 to receive vunakizumab (40, 80, 160, or 240 mg) or placebo subcutaneously, every 4 weeks, until week 12 (2 more drug administrations for the vunakizumab groups on weeks 16 and 20). The primary end point was at least 75% improvement in the Psoriasis Area and Severity Index at week 12. RESULTS: At week 12, there were significantly greater proportions of responders with at least 75% improvement in the Psoriasis Area and Severity Index in all vunakizumab groups compared to placebo (40, 80, 160, and 240 mg: 56.8%, 65.8%, 81.6%, and 86.5%, respectively, vs 5.4%; P < .001 for all); the proportions of patients achieving Physician's Global Assessment responses of 0 or 1 were also higher with vunakizumab (45.9%, 47.4%, 60.5%, and 73.0%, respectively, vs 8.1%). No unexpected adverse effects were observed. LIMITATIONS: The study was relatively short in duration and included no active control. CONCLUSION: Vunakizumab showed promising efficacy for moderate-to-severe plaque psoriasis, with good tolerability, warranting further investigation in larger and longer-term studies.

Metformin Promotes the Hair-Inductive Activity of Three-Dimensional Aggregates of Epidermal and Dermal Cells Self-Assembled in vitro.

INTRODUCTION: Although it has been reported that the antidiabetic drug metformin has multiple extra-hypoglycemic activities, such as anti-oxidation, antiaging, and even antitumor, topical metformin also can induce hair regeneration, but the precise mechanism involved in that process is still unclear. OBJECTIVES: The aim of this study was to assess the effect of metformin on hair growth in a mouse hair-follicle reconstitution model generated by in vitro self-assembled three-dimensional aggregates of epidermal and dermal cells (DCs) (3D aggregates). METHODS: Epidermal cells and DCs were isolated and cultured from the mouse skin of 50 C57BL/6 mouse pups (1-day-old). For tracing the distribution of DCs during the self-assembly process of 3D aggregates, the DCs were labeled with Vybrant Dil Cell-Labeling Solution and mixed with epidermal cells at a 1:1 ratio. Formed 3D aggregates were treated with 10 mM metformin and then were grafted into recipient BALB/c nude mice. The biomarkers (hepatocyte growth factor [HGF], prominin-1 [CD133], alkaline phosphatase [ALP], ß-catenin, and SRY-box transcription factor 2 [SOX2]) associated with the hair-inductive activity of DCs were detected in the grafted skin tissues and in cultured 3D aggregates treated with metformin using immunofluorescent staining, quantitative real-time RT-PCR (qRT-PCR), and Western blotting. Furthermore, the expression levels of CD133 were also examined in DCs with different passage numbers using qRT-PCR and Western blotting. RESULTS: Metformin directly stimulates the activity of ALP of cultured 3D aggregates, upregulates both the protein and mRNA expression levels of molecular markers (HGF, CD133, ALP, ß-catenin, and SOX2), and improves the survival rate of reconstituted hair follicles. Moreover, we also found that metformin increases the expression of CD133 in DCs thus maintaining their trichogenic capacity that would normally be lost by serial subculture. CONCLUSIONS: These results suggest that metformin can promote hair follicle regeneration in vitro through upregulation of the hair-inductive capability of DCs, warranting further evaluation in the clinical treatment of male or female pattern hair loss.

[Updated Molecular Regulation of Hair Growth and Pigmentation by Dermal Papilla Cells].

There is growing evidence that dermal papilla cells(DPCs)act as the organizing center to induce the cyclic hair regeneration.On one hand,DPCs secrete cytokines or growth factors to regulate the differentiation,proliferation,and migration of epithelial stem cells(EpSCs)and melanocyte stem cells(MeSCs)residing in the bulge region.On the other hand,DPCs manipulate the microenvironment(also termed as niche)for both EpSCs and MeSCs,such as the size of dermal papilla,the distance between dermal papilla and the bulge region,and the lymphatic drainage and sympathetic nerve innervation surrounding the bulge region,thereby orchestrating the cycling hair growth.Recent studies have demonstrated at least four subpopulations existing in dermal papillae,which induce the unilineage transit-amplifying epithelial cells to form the concentric multilayers of hair shafts and sheaths.In addition,emerging study has indicated that sustained psychological stress potentially leads to hyperactivation of the sympathetic nerves that innervate the bulge region.The large amount of norepinephrine released by the nerve endings forces MeSCs to rapidly and abnormally proliferate,resultantly causing the depletion of MeSC pool and the loss of hair pigment.Understanding the molecular regulation of hair growth and pigmentation by DPCs holds substantial promise for the future use of cultured DPCs in vitro to treat hair loss.

Botulinum toxin A promotes the transdifferentiation of primary keloid myofibroblasts into adipocyte-like cells.

Keloid is a type of unusually raised scar. Botulinum toxin A (BTX-A) has a great application potential in keloids treatment. Here, we investigated the functional role of BTX-A in keloids. We separated keloid tissues and normal skin tissues from keloid patients and found that the expression of myofibroblast markers, α-SMA, Collagen I, and Collagen III was increased in the keloid tissues as compared with normal skin tissues. Keloid fibroblasts derived from keloid tissues were treated with TGF-ß1 to induce the differentiation of fibroblasts into myofibroblasts. The keloid myofibroblasts displayed a significant up-regulation of α-SMA. BTX-A enhanced the expression of adipocyte markers, PPARγ and C/EBPα, and increased the accumulation of lipid droplets, and reduced the expression of α-SMA, Collagen I, and Collagen III in the keloid myofibroblasts. Moreover, BTX-A enhanced the expression of BMP4 and p-smad1/5/8. Noggin (BMP4 antagonist) treatment reversed BTX-A-mediated increase of PPARγ and C/EBPα expression and lipid droplets, and down-regulation of α-SMA, Collagen I, and Collagen III in primary keloid myofibroblasts. In conclusion, BTX-A promoted the transdifferentiation of primary keloid myofibroblasts into adipocyte-like cells, which may attribute to activate BMP4/Smad signalling pathway. Thus, this study provides new insights into the mechanism of BTX-A in keloid.

Pro-pigmentary action of 5-fluorouracil through the stimulated secretion of CXCL12 by dermal fibroblasts.

BACKGROUND: There is growing evidence that 5-fluorouracil (5-FU) combined with therapeutic trauma can effectively induce skin repigmentation in vitiligo patients who are unresponsive to conventional treatments. Previous studies have mainly focused on identifying the antimitotic activity of 5-FU for the treatment of skin cancer, but few studies have investigated its extra-genotoxic actions favoring melanocyte recruitment. METHODS: We utilized the full thickness excisional skin wound model in Dct-LacZ transgenic mice to dynamically assess the migration of melanocytes in the margins of wounds treated with or without 5-FU. The in-situ expression of CXCL12 was examined in the wound beds using immunofluorescence staining. Quantitative real-time polymerase chain reaction and Western blotting analyses were performed to detect the expression levels of CXCL12 mRNA and protein in primary mouse dermal fibroblasts treated with or without 5-FU. Transwell assays and fluorescein isothiocyanate (FITC)-phalloidin staining were used to observe cell migration and filamentous actin (F-actin) changes of melan-a murine melanocytes. RESULTS: Whole mount and cryosection X-gal staining showed that the cell numbers of LacZ-positive melanocytes were much higher in the margins of dorsal and tail skin wounds treated with 5-FU compared with the controls. Meanwhile, CXCL12 immunostaining was significantly increased in the dermal compartment of wounds treated with 5-FU (control vs. 5-FU, 22.47 ±â€Š8.85 vs. 44.69 ±â€Š5.97, P < 0.05). Moreover, 5-FU significantly upregulated the expression levels of CXCL12 mRNA (control vs. 5-FU, 1.00 ±â€Š0.08 vs. 1.54 ±â€Š0.06, P < 0.05) and protein (control vs. 5-FU, 1.00 ±â€Š0.06 vs. 2.93 ±â€Š0.10, P < 0.05) in cultured fibroblasts. Inhibition of the CXCL12/CXCR4 axis suppressed melanocyte migration in vitro using a CXCL12 small interfering RNA (siRNA) or a CXCR4 antagonist (AMD3100). CONCLUSION: 5-FU possesses a pro-pigmentary activity through activation of the CXCL12/CXCR4 axis to drive the chemotactic migration of melanocytes.

The regional distribution of melanosomes in the epidermis affords a localized intensive photoprotection for basal keratinocyte stem cells.

Human skin is a highly efficient self-renewing barrier that is critical to withstanding environmental insults. Undifferentiated keratinocyte stem cells reside in the basal layer of the epidermis and in hair follicles that continuously give rise to progenies ensuring epidermal turnover and renewal. Ultraviolet (UV) radiation is a proven cause of skin keratinocyte cancers, which preferentially occur at sun-exposed areas of the skin. Fortunately, melanocytes produce melanin that is packaged in specific organelles (termed melanosomes) that are then delivered to nearby keratinocytes, endowing the recipient cells with photoprotection. It has long been thought that melanosome transfer takes place stochastically from melanocytes to keratinocytes via an as-yet-unrecognized manner. However, recent studies have indicated that melanosomes are distributed regionally in the basal layer of the skin, affording localized intensive photoprotection for progenitor keratinocytes and stem cells that reside in the microenvironment of the basal epidermis. In this review, we summarize current knowledge about molecular and cellular mechanisms that are responsible for the selective transfer and exclusive degradation of melanosomes in the epidermis, emphasizing implications for skin carcinogenesis.

Urinary SARS-CoV-2 RNA is An Indicator For The Progression and Prognosis of COVID-19 Disease.

Background: We aimed to analyse clinical characteristics and find potential factors predicting poor prognosis in patients with coronavirus disease 2019 (COVID-19). Methods: We analyzed the demographic and clinical data of COVID-19 patients and detected SARS-CoV-2 RNA in urine sediments collected from 53 COVID-19 patients enrolled in Renmin Hospital of Wuhan University from January 31, 2020 to February 18, 2020 with qRT-PCR analysis, and then classified those patients based on clinical conditions (severe or non-severe syndrome) and urinary SARS-CoV-2 RNA (U RNA - or U RNA + ). Results: We found that COVID-19 patients with severe syndrome (severe patients) showed significantly higher positive rate (11 of 23, 47.8%) of urinary SARS-CoV-2 RNA than non-severe patients (4 of 30, 13.3%, p = 0.006). U RNA + patients or severe U RNA + subgroup exhibited higher prevalence of inflammation and immune discord, cardiovascular diseases, liver damage and renal disfunction, and higher risk of death than U RNA - patients. To understand the potential mechanisms underlying the viral urine shedding, we performed renal histopathological analysis on postmortems of patients with COVID-19 and found that severe renal vascular endothelium lesion characterized by increase of the expression of thrombomodulin and von Willebrand factor, markers to assess the endothelium dysfunction. We proposed a theoretical and mathematic model to depict the potential factors determining the urine shedding of SARS-CoV-2. Conclusions: This study indicated that urinary SARS-CoV-2 RNA detected in urine specimens can be used to predict the progression and prognosis of COVID-19 severity.

Deciphering skin re-pigmentation patterns in vitiligo: an update on the cellular and molecular events involved.

Current treatment of vitiligo is still a great challenge, since most cases of vitiligo have variable re-pigmentation outcomes due to their unpredictable responses to existing therapeutic regimens. There is an urgent need to identify this re-pigmentation process and to develop novel therapies. This review illustrates the most current research and latest understanding of vitiligo skin re-pigmentation and related regulatory mechanisms. Literature was collected from PubMed until January 2020, using the search terms including "vitiligo," "re-pigmentation," "phototherapy," "narrow-band ultraviolet B, " "excimer," "fractional carbon dioxide laser," and "melanocyte stem cells." Literature was mainly derived from English articles. Article type was not limited. Emerging evidence suggests that patients with vitiligo present various re-pigmentation patterns following ultraviolet B phototherapy, which relies on different cell reservoirs from the perilesional margins and/or from uninvolved hair follicles to replenish functional melanocytes that are lost in vitiliginous skin. The following events are likely to be involved in this re-pigmentation process, including: 1) changes in the paracrine secretion and distribution of transforming growth factor-ß1 in the bulge area and in the epidermis; 2) the enhanced transfer of dermal pro-melanogenic growth factors to the epidermis; and 3) the induction of a C-X-C motif chemokine ligand (CXCL) 12-enriched micro-environment that efficiently recruits CXCR4- or CXCR7-positive melanocytes. Ongoing studies on the cellular and molecular events underlying vitiligo re-pigmentation will help design new therapeutic strategies to improve treatment outcomes.

Effects of autologous platelet-rich plasma injections on facial skin rejuvenation.

Autologous serum platelet-rich plasma (PRP) has been used to rejuvenate wrinkled and aged skin for years; however, the molecular mechanism for the positive effects of PRP on the skin remains unclear. The present study aimed to clarify the potential molecular mechanisms for the role of PRP in wrinkled and aged skin rejuvenation, and provide evidence for future clinical applications. A total of 30 healthy females were recruited for PRP treatment and signed informed consent was obtained. A total of 3 autologous PRP injections were administered to each patient with 15-day intervals between injections. The effects of PRP injections were evaluated using the VISIA® Complexion Analysis System and skin computed tomography. A human organotypic skin model was established and treated with PBS or PRP before ultraviolet (UV)-B light (10 mJ/cm2) irradiation. The distribution of the epidermal structure and dermal fibers were analyzed by hematoxylin and eosin and Masson's trichome staining. Expression of matrix metalloproteinase-1 (MMP-1), tyrosinase, fibrillin and tropoelastin was detected by reverse transcription-quantitative PCR, western blotting and immunofluorescence. The present results showed that PRP treatment improved skin quality in the participants. In addition, the VISIA® results showed that wrinkles, texture and pores were decreased in the PRP groups compared with the PBS treatment. The in vitro study demonstrated that PRP treatment ameliorated photoaging by inhibiting UV-B-induced MMP-1 and tyrosinase upregulation, and by inducing fibrillin and tropoelastin expression that was downregulated by UV-B. Collectively, it was demonstrated that PRP treatment ameliorated skin photoaging through regulation of MMP-1, tyrosinase, fibrillin and tropoelastin expression.

Consensus of Chinese experts on protection of skin and mucous membrane barrier for health-care workers fighting against coronavirus disease 2019.

Health professions preventing and controlling Coronavirus Disease 2019 are prone to skin and mucous membrane injury, which may cause acute and chronic dermatitis, secondary infection and aggravation of underlying skin diseases. This is a consensus of Chinese experts on protective measures and advice on hand-cleaning- and medical-glove-related hand protection, mask- and goggles-related face protection, UV-related protection, eye protection, nasal and oral mucosa protection, outer ear, and hair protection. It is necessary to strictly follow standards of wearing protective equipment and specification of sterilizing and cleaning. Insufficient and excessive protection will have adverse effects on the skin and mucous membrane barrier. At the same time, using moisturizing products is highly recommended to achieve better protection.

Role of the p53­TRPM1/miR­211­MMP9 axis in UVB­induced human melanocyte migration and its potential in repigmentation.

Clinical studies have proven that ultraviolet B (UVB) based phototherapy can induce perifollicular and marginal repigmentation patterns in the skin of vitiligo patients. It is, however, difficult to conceive how melanocytes can easily exit from their tightly interconnected epidermal microenvironment to re­enter a different location in the skin to establish a new network with neighboring keratinocytes. While it is known that matrix metalloprotease 9 (MMP9) is involved in the degradation of the extracellular matrix in physiological or pathological processes, little is known about whether MMP9 affects melanocyte migration in vitiligo repigmentation. To investigate the effects of the p53­ transient receptor potential cation channel subfamily M member 1 (TRPM1)/microRNA (miR/miRNA)­211­MMP9 axis to regulate melanocyte migration following exposure to UVB, the expression profile of MMP9 in cultured human melanocytes transfected with or without the miR­211­mimic and p53­GFP lentiviral vector, respectively were determined. Quantitative polymerase chain reaction and western blotting were used to examine p53, TRPM1 and MMP9 mRNA and protein levels in UVB­exposed and unexposed cells. The capacity of melanocytes to migrate on collagen IV substrate was estimated using a Transwell migration assay. Interestingly, the upregulation of p53 and MMP9 at the mRNA and protein levels was evident in melanocytes treated with single or repeat exposures to UVB, whereas levels of TRPM1 and miR­211 were significantly suppressed in UVB­exposed melanocytes compared with the UVB­unexposed control cells. These results indicate that the p53­TRPM1/miR­211­MMP9 axis is significantly activated in melanocytes exposed to UVB. Notably, the ability of melanocyte migration was altered by the overexpression of p53 using a lentiviral vector and by the upregulation of miR­211 using an miRNA mimic. That altered migration could be neutralized by co­treatment with GM6001 (a broad­spectrum MMP inhibitor). Overall, these results show that the MMP9­mediated migration of melanocytes is regulated by a novel mechanism driven by the p53­TRPM1/miR­211­MMP9 axis. Activation of the p53­TRPM1/miR­211­MMP9 axis potentially represents an attractive therapeutic target to improve repigmentation outcomes in vitiligo patients.

Intramelanocytic Acidification Plays a Role in the Antimelanogenic and Antioxidative Properties of Vitamin C and Its Derivatives.

Although vitamin C (VC, L-ascorbic acid) has been widely used as a skin lightening agent for a long time, the mechanism by which it inhibits melanogenesis remains poorly understood. It is well-documented that the intramelanocytic pH is an important factor in regulating tyrosinase function and melanosome maturation. The activity of tyrosinase, the rate-limiting enzyme required for melanin synthesis, is generally minimal in an acidic environment. Given that VC is an acidic compound, we might speculate that the intracellular acidification of melanocytes induced by VC likely reduces melanin content through the suppression of tyrosinase activity. The results of this study reveal that treatment of melanocytes with VC or its derivatives, magnesium ascorbyl phosphate (MAP) and 3-O-ethyl-L-ascorbic acid (AAE), resulted in significant decreases in the tyrosinase activity and melanin content and in the levels of intracellular reactive oxygen species (ROS), indicating that VC and its derivatives possess antimelanogenic and antioxidative activities. Western blotting analysis indicated that VC, MAP, and AAE exert their antimelanogenic activity by inhibiting the tyrosinase activity rather than by downregulating the expression of melanogenic proteins such as tyrosinase, premelanosome protein 17 (Pmel17) and microphthalmia-associated transcription factor (MITF). Further, we found that the reduced tyrosinase activity of melanocytes treated with VC or its derivatives could be reactivated following intracellular neutralization induced by ammonium chloride (NH4Cl) or concanamycin A (Con A). Finally, we examined the expression of sodium-dependent VC transporter-2 (SVCT-2) using western blotting and qPCR, which revealed that there was a significant increase in the expression of SVCT-2 in melanocytes following treatment with VC. VC-mediated intracellular acidification was neutralized by phloretin (a putative SVCT-2 inhibitor) in a dose-dependent manner. Taken together, these data show that VC and its derivatives suppress tyrosinase activity through cytoplasmic acidification that potentially results from enhanced VC transmembrane transport via the VC transporter SVCT-2.

Abnormalities in endothelial form of nitric oxide synthase is pathogenic in limited cutaneous systemic sclerosis.

BACKGROUND: Limited cutaneous systemic sclerosis is one subtype of systemic sclerosis which is characterized by a prototypic multisystem fibrotic disorder. OBJECTIVE: This study aimed to further investigate the pathological mechanism of limited cutaneous systemic sclerosis (lcSSc). METHODS: The dataset GSE76807 generated from 10 lcSSc patients and five healthy controls was used. After the preprocessing of the original data, differentially expressed genes (DEGs) were identified and then performed functional analysis, protein-protein interaction (PPI) network and module analysis. Additionally, the transcription factors (TFs) and miRNAs which potentially regulating DEGs were identified and the co-regulatory network was constructed. Finally, DEGs targeted by current drugs were identified. Real-time quantitative PCR analyses of some DEGs in mice with lcSSc were performed. RESULTS: Total 203 up-regulated and 189 down-regulated DEGs were obtained. The up-regulated genes were enriched in protein interactions at the synapses neuronal system, NCAM1 interactions, and CREB phosphorylation through the activation of CaMKII, while, cilium assembly, and endothelial form of nitric oxide synthase (eNOS) activation were enriched by down-regulated genes. SCRT2 and RABEP1 regulated by miR-218 were hub nodes in the network. DRD4 and GRIN2D were the main drug targets. RABEP1 and SSB were found lowly expressed in mice model with lcSSc. CONCLUSION: Endothelial form of NOS activation would be suppressed, and the process of neuronal migration and outgrowth would be activated to participant in the pathological mechanism of lcSSc.