Research progress and thinking in mouse models of vitiligo-like depigmentation / 中华皮肤科杂志

The etiology and pathogenesis of vitiligo have not yet been clear, and animal models are important tools for vitiligo research. In addition to traditional mouse models of vitiligo, many new models have been gradually established with the deepening of research, such as mouse models expressing epidermal melanocytes and melanocyte-reactive T cells, K14-SCF/h3TA2/HLA-A2 triple-transgenic mouse (Vitesse mice) models, autoimmune-induced mouse models, chemical reagent-induced mouse models, etc. Manifestations of these models are highly similar to human vitiligo, their reproducibility and stability have been improved to different extents, and they have already become good models for exploring the pathogenesis of and therapeutic targets for vitiligo, as well as for evaluating therapeutic efficacy. This review summarizes current research progress and existing problems in mouse models of vitiligo-like depigmentation.

Clinicopathological analysis of 126 cases of infantile congenital melanocytic nevi / 中华皮肤科杂志

Objective:To analyze clinical and histopathological characteristics of infantile congenital melanocytic nevi (ICMN) .Methods:Clinical and pathological data were collected from 126 infants with confirmedly diagnosed congenital melanocytic nevi in Department of Dermatology, Xijing Hospital from January 2015 to January 2020, and were retrospectively analyzed. Chi-square test was used for comparisons of enumeration data.Results:Among the 126 patients with ICMN, 68 were males and 58 were females; 109 (86.5%) presented with skin lesions at birth; 73 (57.9%) were 2 - 3 years old at the first clinic visit. The skin lesions occurred on the head and face (76 cases, 60.3%) , trunk (24 cases, 19.1%) or extremities (26 cases, 20.6%) . There were 36 (28.6%) patients with small congenital nevi, 68 (54.0%) with M1-type medium-sized nevi, 13 (10.3%) with M2-type medium-sized nevi and 9 (7.1%) with giant nevi. Of 126 cases of ICMN, 121 (96.0%) had solitary lesions, 5 (4.0%) had multiple lesions, 44 (34.9%) had nevi with coarse hairs, 15 (11.9%) had nevi complicated by papules or hyperplastic nodules, and 6 (4.8%) had satellite lesions. Pathological subtypes included compound nevus (120 cases, 95.2%) , intradermal nevus (4 cases, 3.2%) , and junctional nevus (2 cases, 1.6%) . Under the microscope, the depth of the skin lesions was < 1 mm in 38 (30.1%) cases, 1 - 2 mm in 61 (48.4%) and > 2 mm in 25 (19.8%) , and 45 (35.7%) cases showed nevus cells infiltrating the subcutaneous fat layer or deeper tissues. Among the 126 ICMN lesions, common pathological features included nevus tissue maturation (100%, 2 cases of junctional nevi were excluded) , pigment granules in the stratum corneum (53 cases, 42.1%) , disordered/asymmetric distribution of nevus cells (80 cases, 63.5%) , scattered epidermal nevus cells (91 cases, 72.2%) , pagetoid spread of epidermal nevus cells (67 cases, 53.2%) , melanophages in the dermis (71 cases, 56.4%) , and nevus cells distributed along hair follicles/sebaceous glands (82 cases, 65.1%) . Special pathological features included nevus cells embedded in the vascular/lymphatic vessels (42 cases, 33.3%) , nevus cell lysis (45 cases, 35.7%) , fibromatous changes (25 cases, 19.8%) , involvement of the arrector pilli muscles (31 cases, 24.6%) , and mast cell infiltration (30 cases, 23.8%) . Pathological patterns of ICMN with different clinical features: the incidences of infiltration depth > 2 mm, pigment granules and columnar pigment granules in the stratum corneum were significantly higher in the giant nevi than in the small and medium-sized nevi ( χ2 = 7.93, 10.76, 5.89 respectively, all P < 0.05) ; the incidences of infiltration depth > 2 mm, epidermal spongiosis with scattered nevus cells, nevus cell nests distributed along the hair follicles/sebaceous glands, fibromatous changes and mast cell infiltration were significantly higher in the skin lesions with coarse hairs than in those without ( χ2 = 28.29, 8.11, 6.22, 7.92, 8.19 respectively, all P < 0.01) ; the incidences of pagetoid spread of epidermal nevus cells and atypical nevus cells were significantly higher in the skin lesions with papules/hyperplastic nodules than in those without papules/hyperplastic nodules ( χ2 = 4.92, 6.30 respectively, both P < 0.05) . Conclusions:The clinical and histopathological characteristics of ICMN are unique, and atypical nevus cells are common in ICMN. The diagnosis and treatment of ICMN need to be based on the combination of clinical and pathological characteristics.

Application of camouflage therapy in vitiligo / 中华皮肤科杂志

At present,specific targeted treatment of vitiligo is still lacking,and there are many limitations of current therapies,such as slow repigmentation process,long duration of treatment and frequent recurrence.As a therapeutic strategy for rapidly improving the appearance of patients,camouflage therapy has a unique advantage in the treatment of various skin diseases.Several studies in China and other countries have shown that the correct use of cosmetic camouflage can effectively improve the appearance and quality of life of patients with vitiligo.This review summarizes the knowledge about various camouflage therapies and related clinical researches on the relationship between camouflage therapies and quality of life of patients with vitiligo,and elaborates application prospects of camouflage therapies in the treatment of vitiligo.

Effects of up-regulation of NF-E2-related factor 2 on mitochondrial biosynthesis and function in an immortalized human vitiligo melanocyte cell line PIG3V / 中华皮肤科杂志

Objective To explore the effects of NF-E2-related factor 2 (Nrf2) overexpression on mitochondrial biosynthesis and function in melanocytes.Methods An immortalized human vitiligo melanocyte cell line PIG3V was used in this study.An overexpression plasmid Nrf2-pEX-1 containing the full-length Nrf2 gene was constructed.PIG3V cells were divided into 3 groups:blank group receiving no treatment,control group transfected with the pEX-1 plasmid,overexpression group transfected with the Nrf2-pEX-1 plasmid.After transfection,real-time quantitative reverse transcription-PCR (RT-PCR) and Western blot were performed to determine the mRNA and protein levels of mitochondrial biosynthesis-related factors (including Nrf2,nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM)) respectively;RT-PCR was also conducted to measure the copy number of mitochondrial DNA (mtDNA),and flow cytometry to estimate mitochondial membrane potential (MMP);luciferase reporter system was used to estimate the intracellular adenosine triphosphate (ATP) level.Statistical analysis was carried out by using a two-sample t-test.Results After transfection,a significant increase was observed in the mRNA expression levels of Nrf2 and NRF1 at 24 hours (both P ＜ 0.001) and in those of Nrf2 and TFAM at 48 hours (both P ＜ 0.05),but no significant change was noted in the mRNA expression level of TFAM at 24 hours (P ＞ 0.05) or in that of NRF1 at 48 hours (P ＞0.05) in the overexpression group compared with the control group.In the case of Nrf2,NRF1 and TFAM protein levels,the overexpression group showed significant increases compared with the control group at 48 hours after transfection (all P ＜ 0.05),while no significant difference was noted between the two groups at 24 hours.Compared with the control group,MMP in the overexpression group increased by 2.313％ at 24 hours (t =5.546,P =0.005) and by 14.872％ at 48 hours (t =8.537,P =0.001) after transfection.Both the relative copy number of mtDNA and ATP level were similar between the overexpression group and control group at 24 hours after transfection (both P ＞ 0.05),but significantly higher in the overexpression group than in the control group at 48 hours (t =5.760,P =0.005;t =22.040,P =0.008).Conclusion Up-regulation of Nrf2 pathway can improve mitochondrial function and biosynthesis in PIG3V cells likely by promoting the expressions of mitochondrial biosynthesis-related genes and proteins.

DJ-1 protects melanocytes against H2O2-induced oxidative stress via reducing intracellular reactive oxygen species(ROS)and inhibiting cell apoptosis / 中华皮肤科杂志

Objective To investigate DJ-1 expression and protective effect against H2O2-induced oxidative stress in primary human melanocytes.Methods The expression and location of DJ-1 in primary melanocytes were identified by immunofluorescence.After cultured melanocytes were exposed to H2O2 for 24 hours,modified MTT assay was used to assess the proliferation of cells and to choose the suitable concentration of H2O2 for the following experiment.Western blot was used to detect D J-1 expression in melanocytes after being treated with 0.5 mmol/L H2O2 for 24 hours.Some melanocytes were divided into 3 groups to be reversely transfected with PBS(mock control group),non-targeting siRNA(negative control group)and DJ-1 targeting siRNA(DJ-1 group).Optical microscopy was utilized to observe the morphologic changes of transfected melanocytes.At 48 hours after the transfection,the melanocytes were stimulated with H2O2 for 24 hours.Subsequently,modified MTT assay,2′,7′-dichlorofluorescein diacetate(DCFH-DA)and annexin Ⅴ-fluorescein isothiocyanate/propidium iodide were used to determine cell viability,intracellular reactive oxygen species (ROS)level and apoptosis rate respectively.Results DJ-1 was expressed in both melanocyte nucleus and cytoplasm,and predominantly in the nucleus.H2O2 inhibited the cell viability in a dose dependent manner.After treatment with H2O2 of 0.5 mmol/L for 24 hours,the cell viability began to decrease in melanocytes with the expression level of DJ-1 being 2.23 times that in the untreated melanocytes(both P ＜ 0.05).Compared with the mock control group,the dendrites of melanocytes in DJ-1 group were obviously shortened with cytoplasm vacuolization.After 24-hour treatment with H2O2 of 0.5 mmol/L,the cell viability in the DJ-1 group dropped to 35％ of that in the mock control group(P ＜ 0.05),while the intracellular ROS fluorescence intensity( FI) and apoptosis rate were higher in the DJ-1 group than in the mock control group (902 ± 40 vs.529± 32,58q％ ± 6.1％ vs.30% ± 3.8％,both P ＜ 0.05).Conclusion DJ-1 can protect melanocytes against H2O2induced oxidative stress likely by decreasing intracellular ROS production and inhibiting ceU apoptosis.

Effects of irradiation with 1064-nm Q-switched Nd:YAG laser on melanogenesis in cultured PIG cells in vitro / 中华皮肤科杂志

Objective To study to the effect of 1064-nm Q-switched Nd:YAG laser irradiation on the melanogenesis in a human epidermal melanocyte line PIG. Methods Cultured PIG cells were irradiated with 1064-nm Q-switched Nd:YAG laser (Medlite C6) at different energy densities for 10 times. After additional culture for various durations, cell viability was detected by MT assay, tyrosinase activity by dopa oxidation assay, mRNA and protein expressions of tyrosinase, tyrosinase related protein (TRP)-1 and TRP-2 by real-time quantitative fluorescent RT-PCR and Westen blotting respectively, Results The irradiation with Q-switched Nd:YAG laser at energy densities from 1 to 3 J/cm2 had no obvious effect on the viability of PIG cells. After irradiation with Nd:YAG laser at 1 J/cm2, PIG cells showed a significant increase in the tyrosinase activity,mRNA expressions of tyrosinase and TRP-1 compared with unirradiated cells (0.563 ± 0.014 vs 0.501 ±0.019, 1.40±0.11 vs 1.0, 1.28 ± 0.03 vs 1.0, all P＜ 0.05), but both the mRNA (0.91 ± 0.17 vs 1.0, P＞0.05) and protein expressions of TRP-2 experienced no significant changes before and after the irradiation.However, a significant decrease was noted in PIG cells irradiated with Nd:YAG laser at 3 J/cm2 in tyrosinase activity, mRNA and protein expressions of tyrosinase (0.70 ± 0.02 vs 1.0, 0.64 ± 0.05 vs 1.0, both P ＜ 0.05),TRP-1 (0.73±0.04 vs l.0, 0.86±0.17 vs l.0, both P＜0.05) andTRP-2 (0.68±0.04 vs l.0,0.69±0.11vs 1.0, both P ＜0.05) in comparison with unirradiated PIG cells. Conclusions The 1064-nm Q-switched Nd:YAG laser irradiation may affect the melanogenesis in PIG cells. With no influence on cell viability, the 1064-nm Q-switched Nd:YAG laser at 1 J/cm2 could enhance melanogenesis, while that at 3 J/cm2 could suppress melanogenesis, in PIG cells.