A multicentre randomized double-blind placebo-controlled phase III study of the efficacy and safety of xeligekimab (GR1501) in patients with moderate-to-severe plaque psoriasis.

BACKGROUND: Xeligekimab (GR1501) is a fully human monoclonal antibody that selectively neutralizes interleukin (IL)-17A and has shown potential efficacy in treating moderate-to-severe psoriasis in preliminary trials. OBJECTIVES: 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 an extension of the treatment schedule to xeligekimab every 4 weeks for a further 40 weeks. Efficacy was assessed by evaluating achievement of Physician Global Assessment (PGA) 0/1 and 75%, 90% and 100% improvement in Psoriasis Area and Severity Index (PASI 75, PASI 90 and PASI 100, respectively). The safety profile was also evaluated. RESULTS: At week 12, PASI 75, PASI 90 and PASI 100 were achieved in 90.7%, 74.4% and 30.2% of patients in the xeligekimab group vs. 8.6%, 1.4% and 0% of patients in the placebo group, respectively. PGA 0/1 was achieved in 74.4% patients in the xeligekimab group and 3.6% of patients in the placebo group. PASI 75 and PGA 0/1 were maintained until week 52. No unexpected adverse events were recorded. CONCLUSIONS: Xeligekimab showed high efficacy and was well tolerated in Chinese patients with moderate-to-severe plaque psoriasis.

Psoriasis is a skin disease characterized by scaly and raised patches of skin on any part of the body. The condition can be caused by a combination of how a person's immune system works, their genes and their environment. A cytokine is a substance secreted by certain cells of the immune system that have an effect on other cells. One such cytokine, called IL-17A, has been associated with different inflammatory diseases, including psoriasis. We conducted a large trial in Chinese people with moderate-to-severe psoriasis to look at the efficacy (ability to produce the intended result) and safety of a medicine called xeligekimab (known as a 'monoclonal antibody') which works by targeting IL-17A. We randomly assigned 420 Chinese patients to receive 200 mg of xeligekimab every 2 weeks or a 'placebo' (no active medicine) for the first 12 weeks. We extended the treatment schedule of xeligekimab to every 4 weeks for a further 40 weeks. To assess how the medicine worked, we measured people's psoriasis symptoms and severity. To assess how safe the medicine was, we looked at the side-effects (or 'adverse events'). The results of this trial showed that xeligekimab improved people's psoriasis and itching starting at week 4 of receiving treatment, and more than 60% of people achieved improvement or remission by week 6, which was sustained up to week 52. The safety of xeligekimab was similar to another medicine classed as a monoclonal antibody (called secukinumab) and there were no new or unexpected adverse events reported. Overall, our findings suggest that xeligekimab is a safe and effective medicine for the treatment of psoriasis in Chinese people.

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.

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.

Efficacy and safety between temozolomide alone and temozolomide-based double therapy for malignant melanoma: a meta-analysis.

Temozolomide (TMZ) has received much attention, notably in the treatment of malignant glioma and malignant melanoma. The objective of this study was to compare the clinical efficacy and safety of TMZ alone and TMZ-based combination drug therapy in patients with melanoma. Using "temozolomide" as a keyword combined with "melanoma" and "randomized controlled trials" as Medical Subject Headings, the following electronic databases were searched: the Cochrane library, MEDLINE, EBSCO, EMBASE, Ovid, cNKI, and cBMDisc. The evaluating indicators were overall response rate (ORR), 1-year survival rate, and several of the most frequent adverse events. Five randomized controlled trials met our criteria and were included in the meta-analysis, with a total of 703 participants (309 patients received TMZ alone, and 394 patients received combined regimens). The meta-analysis showed that the ORR for TMZ-based drug therapy was higher than TMZ alone [relative risk (RR) = 1.44; 95% confidence interval (CI), 1.06-1.95], but the 1-year survival rate was not significantly different between the two groups (RR = 1.13; 95% CI, 0.92-1.40). These results suggested that the impact of these increased response rates was not translated into a survival benefit. Moreover, we found no difference in the incidence of adverse events analyzed. The currently available evidence showed that the TMZ-combination therapy may moderately improve the response rate, but there was no corresponding increased toxicity. Future large-scale, high-quality, placebo-controlled, double-blind trials are needed.

The multi-lineage differentiation and angiogenesis ability of adipose-derived adult mesenchymal stem cells.

BACKGROUND: To investigate the in vitro multi-lineage differentiation of adipose-derived adult stem cells and their ability to differentiate into endothelial cells. METHODS: Adipose-derived adult stem cells were isolated for detection of the immune phenotype, cell doubling time, cycle, and induction of endothelial cell differentiation in vitro. The expression of endothelial cell-specific surface markers was measured immunocytochemically. RESULTS: Adipose-derived adult stem cells have multi-lineage differentiation potential and can differentiate into endothelial cells in vitro. CONCLUSIONS: Adipose-derived adult stem cells have the same differentiation ability with those derived from the bone marrow, as both can differentiate into endothelial cells. These findings have opened up the prospect of adipose-derived adult stem cells in angiogenesis therapy.

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.

Involvement of interferon γ-producing mast cells in immune responses against melanocytes in vitiligo requires MrgX2 activation.

BACKGROUND: Increasing evidence indicates that oxidative stress and interferon γ (IFNγ)-driven cellular immune responses are responsible for the pathogenesis of vitiligo. However, the connection between oxidative stress and the local production of IFNγ in early vitiligo remains unexplored. The aim of this study was to identify the mechanism underlying the production of IFNγ by mast cells and its impact on vitiligo pathogenesis. METHODS: Skin specimens from the central, marginal, and perilesional skin areas of active vitiligo lesions were collected to characterize changes of mast cells, CD8+ T cells, and IFNγ-producing cells. Cell supernatants from hydrogen peroxide (H2O2)-treated keratinocytes (KCs) were harvested to measure levels of soluble stem cell factor (sSCF) and matrix metalloproteinase (MMP)-9. A murine vitiligo model was established using Mas-related G protein-coupled receptor-B2 (MrgB2, mouse ortholog of human MrgX2) conditional knockout (MrgB2-/-) mice to investigate IFNγ production and inflammatory cell infiltrations in tail skin following the challenge with tyrosinase-related protein (Tyrp)-2 180 peptide. Potential interactions between the Tyrp-2 180 peptide and MrgX2 were predicted using molecular docking. The siRNAs targeting MrgX2 and the calcineurin inhibitor FK506 were also used to examine the signaling pathways involved in mast cell activation. RESULTS: IFNγ-producing mast cells were closely aligned with the recruitment of CD8+ T cells in the early phase of vitiligo skin. sSCF released by KCs through stress-enhanced MMP9-dependent proteolytic cleavage recruited mast cells into sites of inflamed skin (Perilesion vs. lesion, 13.00 ± 4.00/HPF vs. 26.60 ± 5.72/HPF, P <0.05). Moreover, IFNγ-producing mast cells were also observed in mouse tail skin following challenge with Tyrp-2 180 (0 h vs. 48 h post-recall, 0.00 ± 0.00/HPF vs. 3.80 ± 1.92/HPF, P <0.05). The IFNγ+ mast cell and CD8+ T cell counts were lower in the skin of MrgB2-/-mice than in those of wild-type mice (WT vs. KO 48 h post-recall, 4.20 ± 0.84/HPF vs. 0.80 ± 0.84/HPF, P <0.05). CONCLUSION: Mast cells activated by MrgX2 serve as a local IFNγ producer that bridges between innate and adaptive immune responses against MCs in early vitiligo. Targeting MrgX2-mediated mast cell activation may represent a new strategy for treating vitiligo.

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.

Increased splicing of CXCR3 isoform B (CXCR3B) by impaired NRF2 signaling leads to melanocyte apoptosis in active vitiligo.

Apoptotic melanocytes (MCs) may release neoantigenic epitopes preceding epidermal infiltration by autoreactive CD8+ T cells in early vitiligo. However, the mechanism by which vitiligo MCs are prone to apoptosis under oxidative stress remains elusive. Pro-apoptotic receptor C-X-C motif chemokine receptor 3 isoform B (CXCR3B) is critical for inducing MC apoptosis in the inflammatory microenvironment of lesional vitiligo skin. Here, we show that C-X-C motif chemokine ligand 10 (CXCL10), a functional ligand for CXCR3B, is upregulated in primary dermal fibroblasts and in CD90+ reticular fibroblasts of vitiligo skin. The number of CXCR3B+ MCs was increased in active vitiligo skin compared with healthy skin and stable vitiligo skin. Mechanistically, impaired nuclear factor erythroid 2-related factor 2 (NRF2) signaling in oxidatively stressed MCs leads to the elevated expression of CXCR3B and increased apoptosis. The overexpression of NRF2 prevents MCs from CXCL10-induced apoptosis through upregulation of pro-survival receptor CXCR3 isoform A (CXCR3A). Overall, MCs expressing CXCR3B are more susceptible to apoptosis. Suppressing CXCR3B could be a promising therapeutic approach to extinguish inflammation in vitiligo skin.

Efficacy and Safety of Crisugabalin (HSK16149) in Adults with Postherpetic Neuralgia: A Phase 3 Randomized Clinical Trial.

Importance: China carries a heavy burden of postherpetic neuralgia, with an unmet need for novel drugs with greater efficacy and less prominent neurotoxic effects than existing calcium channel ligands. Objective: To investigate the efficacy and safety of crisugabalin, an oral calcium channel α2δ-1 subunit ligand, for postherpetic neuralgia. Design, Setting, and Participants: This randomized clinical trial, carried out between November 9, 2021, and January 5, 2023, at 48 tertiary care centers across China had 2 parts. Part 1 was a phase 3, multicenter, randomized, double-blind, placebo-controlled, parallel-group study consisting of a 2-week screening period, a 7-day run-in period, and a 12-week double-blind treatment period. Part 2 was a 14-week open-label extension study. Investigators, statisticians, trial clinicians, and patients were blinded to trial group assignments. Participants included adults with postherpetic neuralgia with an average daily pain score (ADPS) of at least 4 on the 11-point Numeric Pain Rating Scale over the preceding week, with the exclusion of patients with pain not controlled by prior therapy with pregabalin (≥300 mg/d) or gabapentin (≥1200 mg/d). Interventions: Patients were randomized 1:1:1 to receive crisugabalin, 20 mg twice daily (ie, 40 mg/d), and crisugabalin, 40 mg twice daily (ie, 80 mg/d), or placebo for 12 weeks. Eligible patients received crisugabalin, 40 mg, twice daily during extension. Main Outcome and Measure: The primary efficacy end point was the change from baseline in ADPS at week 12. Results: The study enrolled 366 patients (121 patients receiving crisugabalin, 40 mg/d; 121 patients receiving crisugabalin, 80 mg/d; 124 patients receiving placebo; median [IQR] age, 63.0 [56.0-69.0] years; 193 men [52.7%]). At week 12, the least squares mean (SD) change from baseline in ADPS was -2.2 (0.2) for crisugabalin, 40 mg/d, and -2.6 (0.2) for crisugabalin, 80 mg/d, vs -1.1 (0.2) for placebo, with a least squares mean difference of -1.1 (95% CI, -1.6 to -0.7; P < .001) and -1.5 (-95% CI, -2.0 to -1.0; P < .001) vs placebo, respectively. No new safety concerns emerged. Conclusions and Relevance: Crisugabalin, 40 mg/d, or crisugabalin, 80 mg/d, was well tolerated and demonstrated a statistically significant improvement in ADPS over placebo. Trial Registration: ClinicalTrials.gov Identifier: NCT05140863.

Insufficient expression of the melanocortin-1 receptor by human dermal fibroblasts contributes to excess collagen synthesis in keloid scars.

Activation of the α-melanocyte-stimulating hormone (αMSH)/melanocortin-1 receptor (MC1R) signalling pathway exerts antagonistic actions on cutaneous inflammatory and fibrogenic responses in addition to promoting pigment production. Herein, the expression of MC1R by keloid-derived fibroblasts and keloid scar tissue was investigated using a range of techniques. MC1R mRNA expression levels in five different keloid fibroblast cell lines were significantly reduced to less than half compared with five normal fibroblast cell lines (P < 0.05). Immunohistological analysis of tissue samples indicated that MCR1 immunoreactivity in both epidermal and dermal compartments of five keloid tissue samples was dramatically decreased compared with normal skin (P < 0.05). Insufficient expression of MC1R on human dermal fibroblasts might abolish the αMSH-mediated suppression of collagen production and myofibroblast transformation elicited by the profibrotic cytokine-transforming growth factor-ß1. Restoration of reduced MC1R by dermal fibroblasts may lead to novel scar-reducing therapeutic approaches for treating this refractory fibrotic disease.

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.

Detailed histological structure of human hair follicle bulge region at different ages: a visible niche for nesting adult stem cells.

In the bulge region of the hair follicle, a densely and concentrically packed cell mass is encircled by the arrector pili muscle (APM), which offers a specilized microenvironment (niche) for housing heterogeneous adult stem cells. However, the detailed histological architecture and the cellular composition of the bulge region warrants intensive study and may have implications for the regulation of hair follicle growth regulation. This study was designed to define the gene-expression profiles of putative stem cells and lineage-specific precursors in the mid-portions of plucked hair follicles prepared according to the presence of detectable autofluorescence. The structure was also characterized by using a consecutive sectioning technique. The bulge region of the hair follicle with autofluorescence was precisely excised by employing a micro-dissection procedure. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was performed to identify the gene expression profiles specific for epithelial, melanocyte and stromal stem cells in the bulge region of the hair follicle visualized by autofluorescence. The morphology and its age-dependent changes of bulge region of the hair follicles with autofluorescence segment were also examined in 9 scalp skin specimens collected from patients aged 30 weeks to 75 years, by serial sectioning and immuno-staining. Gene expression profile analysis revealed that there were cells with mRNA transcripts of Dct(Hi)Tyrase(Lo)-Tyrp1(Lo)MC1R(Lo)MITF(Lo)/K15(Hi)/NPNT(Hi) in the bulge region of the hair follicle with autofluorescence segments, which differed from the patterns in hair bulbs. Small cell-protrusions that sprouted from the outer root sheath (ORS) were clearly observed at the APM inserting level in serial sections of hair follicles by immunohistological staining, which were characteristically replete with K15+/K19+expressing cells. Likewise, the muscle bundles of APM positive for smooth muscle actin intimately encircled these cell-protrusions, and the occurrence frequency of the cell-protrusions was increased in fetal scalp skin compared with adult scalp skin. This study provided the evidence that the cell-protrusions occurring at the ORS relative to the APM insertion are more likely to be characteristic of the visible niches that are filled with abundant stem cells. The occurrence frequency of these cell-protrusions was significantly increased in fetal scalp skin samples (128%) as compared with the scalp skins of younger (49.4%) and older (25.4%) adults (P<0.01), but difference in the frequency between the two adult groups were not significant. These results indicated that these cell-protrusions function as a niche house for the myriad stem cells and/or precursors to meet the needs of the development of hair follicles in an embryo. The micro-dissection used in this study was simple and reliable in excising the bulge region of the hair follicle with autofluorescence segments dependent on their autofluorescence is of value for the study of stem cell culture.

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.

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.

CTLA-4 gene polymorphism and the risk of systemic lupus erythematosus in the Chinese population.

Several variants of CTLA-4 have been reported to be associated with susceptibility systemic lupus erythematosus (SLE); however, findings have been inconsistent across different populations. Using a case-control study design, we have investigated the role of CTLA-4 polymorphism at positions -1661 and -1722 on SLE susceptibility in our Chinese SLE population in central China's Hubei province. Samples were collected from 148 SLE patients and 170 healthy controls. Polymerase chain reaction restriction fragments length polymorphism (PCR-RFLP) was used to analyze the genotypes of the two sites. Statistically significant difference was observed in genotypes for -1722, but not for -1661. The frequency of the T allele on the -1722 SNP was significantly increased in SLE patients: 57.8% versus 40.6% in controls (P < 0.001, OR = 2.002). While the detected C allele frequency in the controls was significantly elevated in comparison to that in the SLE patients (59.4% versus 42.2%). On the contrary, no association was found between SLE and CTLA-4 polymorphism at position -1661.

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.

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.