EGR1 Mediated Reduction of Fibroblast Secreted-TGF-β1 Exacerbated CD8+ T Cell Inflammation and Migration in Vitiligo

Vitiligo is a T cell-mediated depigment skin disease caused by the complex interplay between melanocyte dysfunction, environmental stimulation, and dysregulated immune signals. Transforming growth factor-β1 (TGF-β1), which typically derives from regulatory T cells, has long been identified at low levels in the peripheral system of vitiligo patients. Here, through RNA-sequencing and transcription factor enrichment, we revealed that in response to CD8+ T cell-secreted interferon-gamma (IFN-γ), stromal fibroblast downregulates early growth response 1 (EGR1) activity, leading to TGF-β1 deficiency. The defective immune regulation loop further exacerbated local CD8+ T cell inflammation and promoted inflammatory cell migration in vitiligo. Thus, fibroblast-derived TGF-β1 plays an important stromal signal in vitiligo pathogenesis.

Caffeic acid derivative WSY6 protects melanocytes from oxidative stress by reducing ROS production and MAPK activation

Purpose

Vitiligo is a chronic depigmentation disease caused by a loss of functioning melanocytes and melanin from the epidermis. Oxidative stress-induced damage to melanocytes is key in the pathogenesis of vitiligo. WSY6 is a caffeic acid derivative synthesized from epigallocatechin-3-gallate (EGCG). This study is to investigate whether the new chemical WSY6 protected melanocytes from H2O2-induced cell damage and to elucidate the underlying molecular mechanism.

Patients and methods

The present study compared the antioxidative potential of WSY6 with EGCG in hydrogen peroxide (H2O2)-treated PIG1 cells. Western blotting was used to study the protein expression of cyto-c, cleaved-caspase3, cleaved-caspase9, and the activation of MAPK family members, including p38, ERK1/2, JNK and their phosphorylation in melanocytes. ROS assay kit to detect intracellular reactive oxygen species production; CCK8 and lactate dehydrogenase leak assay to detect cytotoxicity.

Results

EGCG and WSY6 ameliorated H2O2-induced oxidative stress damage in PIG1 cells in a does-dependent manner, while WSY6 was much more effective. WSY6 reduced cellular ROS production, cytochrome c release, downregulated caspase-3 and caspase-9 activation. MAPK pathway signaling including phosphorylated p38, ERK and JNK were observed under oxidative stress and can be much protected by pre-treatment of WSY6.

Conclusion

These results indicated that WSY6 could be a more powerful antioxidant than EGCG and protect melanocytes against oxidative cytotoxicity.

Generalized Vitiligo After Stem Cell Transplantation: A Case Report

Graft versus host disease (GVHD) is a complex immune-mediated pathophysiological process, which is caused by allogenic immune reactions between donors and recipients. No matter ac-ute or chronic GVHD, skin involvement is the most common, severe skin damage can lead to permanent disfigurement, which seriously affects the long-term quality of life of patients. We herein report a patient with generalized vitiligo after allogeneic peripheral hematopoietic stem cell transplantation (allo-HSCT) for aplastic anemia.

Impacts of exposure to topical calcineurin inhibitors on metabolism in vitiligo infants

BACKGROUND

Tacrolimus ointment is a recently developed topical immunomodulator that has been approved for use in patients with vitiligo older than 2 years. Concern regarding potential systemic toxic effects has limited treatment options for children younger than 2 years. We wanted to determine whether topical tacrolimus therapy is safe and effective in patients with vitiligo younger than 2 years.

METHODS

The present 6-month clinical trial was conducted to evaluate the efficacy and safety of 0.03% tacrolimus in the treatment of vitiligo in children under 2 years of age. Meanwhile, serum and urine samples were collected, and liquid chromatography-mass spectrometry was performed to generate the serum and urine metabolic profile data of patients and healthy controls.

RESULTS

The overall response rate at the sixth month, which was defined by the degree of re-pigmentation, was 100%. As revealed by blood monitoring and metabolite detection 6 months later, there was no difference between the treatment group and the control group. There is no evidence that long-term topical application of 0.03% tacrolimus ointment will cause metabolite or other physical changes in the body.

CONCLUSIONS

Tacrolimus ointment appears to be effective and safe in the treatment of vitiligo in children younger than 2 year.

TRIAL REGISTRATION

http://www.chictr.org.cn identifier: ChiCTR 2100045920.

IMPACT

We first reported the efficacy and safety of topical application of 0.03% tacrolimus ointment in infants with vitiligo characterized by the metabolites. There is no evidence that long-term topical application of 0.03% tacrolimus ointment will cause metabolite or other physical changes in the body. This study provide evidence for the TCI treatment of infants with vitiligo.

Repigmentation in two patients with vitiligo on AcEGCG 0.5% cream

Per-acetylated epigallocatechin-3-gallate (AcEGCG), a fully acetylated derivative of EGCG, a more potent agent for protection of melanocytes from oxidative damage. We present two patients with vitiligo treated with AcEGCG 0.5% cream, who demonstrated skin repigmentation and control of depigmentation progression.

Narrowband Ultraviolet B Combined with Topical Simvastatin Solution in the Treatment of Vitiligo: A Case Report

Background: Phototherapy is one of the treatments for vitiligo. To be specific, the combination of narrowband ultraviolet B (NB-UVB) with topical preparations has currently become the most common therapeutic modality. Moreover, the research on new topical drug has been a hot issue in the field of vitiligo. Objective: At present, simvastatin has been considered as a potential therapeutic agent for the treatment of vitiligo. To the best of our knowledge, this is the first case report concerning the successful application of NB-UVB combined with topical simvastatin in the treatment of vitiligo. Methods: In this article, a clinical case report was presented, where the patient was not responsive to NB-UVB but was markedly responsive to the treatment of UVB combined with topical simvastatin. Results: A 34-year-old Chinese female patient with vitiligo was cured by NB-UVB combined with topical simvastatin solution. Conclusions: NB-UVB combined with topical simvastatin may be a potential treatment against vitiligo. This research was approved by the Medical Ethics Committee of Third People's Hospital of Hangzhou.

[Corrigendum] The role of VIT1/FBXO11 in the regulation of apoptosis and tyrosinase export from endoplasmic reticulum in cultured melanocytes

Following the publication of the above article, an interested reader drew to the authors' attention that the Transwell cell migration assay data shown in Fig. 4A appeared to be partly overlapping with data presented for experiments performed under different experimental conditions in Figs. 4D and E. The authors independently examined the figure and realized that inadvertent errors had been made during the assembly of Fig. 4; furthermore, owing to the time that has elapsed since this paper was published, the authors no longer had access to the original data. Accordingly, to further verify the conclusions reported in the study, the authors repeated these experiments, and the results obtained were found to be consistent with the original findings. The new version of Fig. 4 is shown below. The authors are grateful to the Editor of International Journal of Molecular Medicine for allowing them the opportunity to publish this Corrigendum, and apologize to the readership for any inconvenience caused. [the original article was published in International Journal of Molecular Medicine 26: 57-65, 2010; DOI: 10.3892/ijmm_00000435].

CXCL9 as a key biomarker of vitiligo activity and prediction of the success of cultured melanocyte transplantation

This study aimed to investigate the potential biomarkers of vitiligo by evaluating the disease activity and curative effect of autologous cultured pure melanocyte transplantation (CMT) on patients. Altogether, 36patients with stable vitiligo were treated with CMT. Blister fluid samples were collected from patients with stable vitiligo. Patients with active vitiligo were matched with healthy controls. The chemokine levels in the serum and blister fluid samples were measured using Luminex. The curative effect on patients with stable vitiligo was evaluated 6 months after treatment. Treatment responses were defined according to the extent of repigmentation as effective (if 50% or more repigmentation was achieved) or ineffective (if less than 50% or worse repigmentation was achieved). Patients received re-transplantation if the initial treatment was ineffective. The levels of C-X-C motif chemokine ligand (CXCL)9 and CXCL10 in blister fluid samples were significantly lower in stable patients than in active participants. Receiver operating characteristic analysis revealed that the levels of CXCL9 and CXCL10 were sensitive and specific in diagnosing active vitiligo. Further, 65.6% (21/32) of patients who received CMT had effective treatment responses. The high CXCL9 level in the blister fluid was a significant predictor of ineffective treatment responses. The treatment response was significantly enhanced after treatment. Four patients with ineffective treatment responses received anti-inflammatory treatment and re-transplantation. The CXCL9 and CXCL10 levels in the blister fluid were related to the presence of active vitiligo. Also, the CXCL9 level was a predictor of the effectiveness of CMT in treating vitiligo.

Altered circulating memory T cells in vitiligo cases followed NB-UVB therapy

Background

Vitiligo represents a commonly diagnosed autoimmune disease caused by the depletion of epidermal melanocytes. Many subsets of T cells contribute to vitiligo pathogenesis, including resident and circulating memory T cells.

Objectives

To analyze the amounts of CD4⁺ and CD8⁺memory T‐cell subsets in peripheral blood specimens from vitiligo patients and alterations caused by narrowband ultraviolet B (NB‐UVB) phototherapy.

Methods

Circulating CD4⁺ and CD8⁺ central memory T (T_CM) and effector memory T (T_EM) cell frequencies in 33 patients with non‐segmental vitiligo and 16 healthy donors were evaluated by flow cytometry. Related chemokine levels were also detected.

Results

Peripheral blood CD4⁺ T_CM and CD8⁺ T_CM counts were markedly reduced in vitiligo cases while they were higher in active vitiligo compared with stable vitiligo cases. Circulating CD8⁺ T_CM frequency in vitiligo was closely related to disease duration. Interestingly, CD4⁺ T_CM and CD8⁺ T_CM frequencies, alongside CXCL9 and CXCL10 amounts in peripheral blood of patients with vitiligo, were significantly decreased after NB‐UVB phototherapy.

Conclusions

Decreased frequencies of circulating CD4⁺ T_CM and CD8⁺ T_CM by NB‐UVB suggest a possible immunosuppressive effect of phototherapy. The chemokines CXCL9 and CXCL10 are the bridge between circulating and skin resident memory T cells. NB‐UVB blocks the homing of circulating memory T cells into vitiligo lesions by down‐regulating CXCL9 and CXCL10. Targeting the above proteins could provide novel, durable treatment options to cure and prevent flares of this disease.

Topical epigallocatechin-3-gallate in the treatment of vitiligo

OBJECTIVE

To preliminarily assess the efficacy and safety of the topical application of Epigallocatechin-3-gallate (EGCG) in treating vitiligo, a 6-month clinical trial was carried out.

METHOD

Patients were randomly given topical application of EGCG on the assigned lesions, with pimecrolimus being used as the control for twice a day over a 6-month treatment period. Responses to treatment were assessed based on the changes in VASI score for percentage reduction in body surface area and the PGA scores.

RESULTS

According to our results, both drugs were discovered to be markedly effective on repigmentation. The VASI of lesion had diminished from 1.19 ± 0.42 to 0.63 ± 0.38, in the EGCG-treated lesions, while from 1.18 ± 0.43 to 0.61 ± 0.36 in the pimecrolimus-treated lesions, and there was no statistically significant difference in VASI score between the EGCG-treated lesions and pimecrolimus-treated lesions (P = 0.755). Meanwhile, the mean PGA score on the EGCG applied side was 4.39 ± 2.23, while that was 4.43 ± 2.02 on the pimecrolimus applied side (P = 0.886). Furthermore, difference in the improvement degree between pimecrolimus side and EGCG side was not statistically significant (P = 0.845). Notably, no serious side effects were observed throughout the study.

CONCLUSION

Findings of the study indicate that topical EGCG can be effective on treating vitiligo.

Decreased SUMOylation of the retinoblastoma protein in keratinocytes during the pathogenesis of vitiligo

The role of SUMOylation in the pathogenesis of vitiligo has not been reported previously. The present study aimed to reveal abnormalities in small ubiquitin‑like modifier (SUMO) conjugation in keratinocytes from depigmented lesions of patients with vitiligo and confirm the role of SUMOylation in keratinocytes from patients with vitiligo. Skin samples used for immunohistochemistry were obtained by punch biopsy from the depigmented lesions of 6 patients. Blisters were produced by vacuum and the roofs were collected for keratinocyte culture. HaCaT cells were transduced with SUMO1 knockdown vectors. The protein expression of SUMO1, SUMO‑specific peptidase 1 (SENP1), ubiquitin‑conjugating enzyme E2 I (Ubc9), SUMO‑activating enzyme subunit 1 (SAE1), cyclin‑dependent kinase (CDK)2, CDK6, proliferating cell nuclear antigen (PCNA), retinoblastoma protein (Rb), phosphorylated Rb (pRb) and β‑actin was assessed by western blotting. The SUMOylation status of proteins was assessed by immunoprecipitation. Cell cycle analysis was performed by flow cytometry and cell proliferation rate was investigated using a Cell Counting Kit‑8. The results demonstrated that the levels of SUMO1‑conjugated proteins were decreased in vitiligo lesions and vitiligo keratinocytes compared with normal controls. The protein expression of Ubc9 was decreased and SENP1 was increased in vitiligo keratinocytes compared with normal keratinocytes, with no alterations in SAE1 expression. Following knockdown of SUMO1 in HaCaT cells, the proliferation of HaCaT cells was reduced and the cell cycle was arrested in G1 phase. Furthermore, the protein expression levels of PCNA, CDK2, CDK6 and pRb were reduced in SUMO1‑knockdown HaCaT cells, and SUMOylated Rb was also decreased markedly in keratinocytes from lesions of patients with vitiligo compared with normal keratinocytes. In conclusion, vitiligo lesions in the present study exhibited dysregulated SUMOylation and deSUMOylation balance and dysregulation of cell cycle progression may be present in SUMO1 knockdown HaCaT cells. These results indicate that deSUMOylation of Rb of keratinocytes may serve an important role in vitiligo, providing a novel direction for the study into the mechanism of vitiligo.

Role of chemokines and the corresponding receptors in vitiligo: A pilot study

To determine the levels and sources of chemokines in the serum and epidermis of vitiligo patients, we examined 80 active patients, 80 stable patients and 40 healthy controls. First, the serum levels of candidate chemokines were measured by Luminex assay, and levels of CCR5, CXCR1 and CXCR3 were measured in peripheral mononuclear cells (PMBC) by flow cytometry. Then, the local epidermis levels of elevated chemokines in vitiligo were tested by Luminex. Finally, the mRNA and protein expression levels of elevated chemokines in HaCaT cells stimulated with interferon (IFN)-γ or tumor necrosis factor (TNF)-α were tested by quantitative real-time polymerase chain reaction and Luminex. The serum levels of CCL5, CXCL8 and CXCL10 in active vitiligo were significantly elevated compared with those in stable vitiligo patients. Furthermore, the levels of CCL3 and CCL4 had weak and positive correlations with the Vitiligo Area Scoring Index. In the peripheral blood of active vitiligo patients, the percentages of CD3⁺ CD8⁺ CCR5⁺ and CD3⁺ CD8⁺ CXCR3⁺ T cells were significantly increased compared with those in stable vitiligo and healthy controls. In the epidermis of lesions, the expression levels of CCL5 and CXCL10 in active vitiligo were significantly increased. In addition, the mRNA and protein levels of CCL5, CXCL8 and CXCL10 were significantly elevated in HaCaT cells after stimulation with TNF-α or IFN-γ. The CCR5/CCL5 and CXCR3/CXCL10 axes may play an important role in the progression and maintenance of vitiligo. Moreover, keratinocytes stimulated with TNF-α and IFN-γ may be a primary source of CCL5 and CXCL10.

Novel approaches to vitiligo treatment via modulation of mTOR and NF-κB pathways in human skin melanocytes

Vitiligo is a skin depigmentation disorder with an increasing prevalence. Among recognized mechanisms is the oxidative stress that affects melanocytes which are responsible for skin pigmentation. Studies have shown that high concentration of hydrogen peroxide, or H₂O₂, induces apoptotic activities. Few studies have been done with lower doses of H₂O₂. Using human skin melanocytes, we investigated the effect of moderate concentration of H₂O₂ on melanocyte dendrites. Confocal data show that H₂O₂ at 250 µM induces loss of dendrites, as indicated by cytoskeletal proteins. α-melanocyte stimulating hormone or α-MSH pretreatment protects against H₂O₂-induced loss of dendrites, while α-MSH alone enhances dendrites. PI3K/AKT inhibitor LY294002 and mTORC1 inhibitor Rapamycin inhibit α-MSH-induced dendrites. In this study, we also investigated the effect of TNFα on cultured human skin melanocytes, since TNFα plays important roles in vitiligo. Confocal data demonstrate that TNFα induces NFκB activation. Western blot analysis shows that TNFα induces IκB phosphorylation and degradation. Interestingly, α-MSH does not have any effect of TNFα-induced IκB degradation and NF-κB activation. α-MSH, however, activates mTORC1 pathway. TNFα induces p38 but not AMPKα activation. Collectively, our data suggest that modulation of mTOR and NF-κB pathways may be a novel approach for better clinical management of vitiligo.

One-pot synthesis of nitrogen-enriched carbon spheres for hexavalent chromium removal from aqueous solution

Nitrogen-enriched carbon spheres (NECS) with high nitrogen content (10.21 wt%) had been prepared and presented superior Cr(vi) removal capacity as high as 279 mg g⁻¹.

The therapeutic effects of EGCG on vitiligo

Epigallocatechin-3-gallate (EGCG) is one of the main chemical constituents of green tea, which has been used as an important traditional Chinese medicine. Green tea has anti-inflammatory, anti-oxidant, and immunomodulatory properties. However, the effects of EGCG on vitiligo are not known. We assessed the role of EGCG in vitiligo induced by monobenzone in mice. We demonstrated that EGCG: delayed the time of depigmentation; reduced the prevalence of depigmentation; and decreased the area of depigmentation. Examination of depigmented skin treated with EGCG by reflectance confocal microscopy suggested increased numbers of epidermal melanocytes and histologic examination showed decreased perilesional accumulation of CD8(+) T cells. To further investigate the mechanism of the anti-inflammatory effects of EGCG, levels of inflammatory mediator tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-6 were tested by enzyme-linked immunosorbent assay. Serum cytokine levels were significantly decreased after administration of EGCG compared with the model group. These results suggested that EGCG may have protective effects against vitiligo, and that it could contribute to suppression of activation of CD8(+) T cells and inflammatory mediators. Based on these results, 5% EGCG was considered to be the most suitable concentration for treating vitiligo, and was used for further study. In addition, we investigated the gene-expression profile of this model in relation to EGCG. Using a 4×44K whole genome oligo microarray assay, 1264 down-regulated genes and 1332 up-regulated genes were recorded in the 5% EGCG group compared with the model group, and selected genes were validated by real-time polymerase chain reaction. Our study demonstrated that EGCG administration was significantly associated with a decreased risk of vitiligo. EGCG could be a new preventive agent against vitiligo in the clinical setting.

Interferon-γ induces senescence in normal human melanocytes

BACKGROUND

Interferon-γ (IFN-γ) plays an important role in the proceedings of vitiligo through recruiting lymphocytes to the lesional skin. However, the potential effects of IFN-γ on skin melanocytes and the subsequent contribution to the vitiligo pathogenesis are still unclear.

OBJECTIVE

To investigate the effects of IFN-γ on viability and cellular functions of melanocytes.

METHODS

Primary human melanocytes were treated with IFN-γ. Cell viability, apoptosis, cell cycle melanin content and intracellular reactive oxygen species (ROS) level were measured. mRNA expression was examined by real-time PCR. The release of interleukin 6 (IL-6) and heat shock protein 70 (HSP-70) was monitored by ELISA. β-galactosidase staining was utilized to evaluate melanocyte senescence.

RESULTS

Persistent IFN-γ treatment induced viability loss, apoptosis, cell cycle arrest and senescence in melanocytes. Melanocyte senescence was characterized as the changes in pigmentation and morphology, as well as the increase of β-galactosidase activity. Increase of p21Cip1/Waf1 protein was evident in melanocytes after IFN-γ treatment. IFN-γ induction of senescence was attenuated by siRNAs against p21, Janus kinase 2 (JAK2) or signal transducer and activator of transcription 1 (STAT1), but not by JAK1 siRNA nor by p53 inhibitor pifithrin-α. IFN-γ treatment increased the accumulation of intracellular ROS in melanocytes, while ROS scavenger N-acetyl cysteine (NAC) effectively inhibited IFN-γ induced p21 expression and melanocyte senescence. IL-6 and HSP-70 release was significantly induced by IFN-γ treatment, which was largely inhibited by NAC. The increase of IL-6 and HSP-70 release could also be observed in senescent melanocytes.

CONCLUSION

IFN-γ can induce senescence in melanocytes and consequently enhance their immuno-competency, leading to a vitiligo-prone milieu.

Dermal mesenchymal stem cells (DMSCs) inhibit skin-homing CD8+ T cell activity, a determining factor of vitiligo patients' autologous melanocytes transplantation efficiency

We here investigated the efficiency of autologous melanocyte transplantation of 23 vitiligo patients by focusing on perilesional skin homing CD8+ T lymphocytes, and studied the potential effect of dermal mesenchymal stem cells (DMSCs) on CD8+ T cell activities in vitro. Out of 23 patients with the autologous melanocyte transplantation, 12 patients (52.17%) had an excellent re-pigmentation, 6 patients (26.09%) had a good re-pigmentation, 5 patients (21.74%) had a fair or poor re-pigmentation. CD8+ T cells infiltrating was observed in the perilesional vitiligo area of all patients. Importantly, the efficiency of the transplantation was closely associated with skin-homing CD8+ T cell activities. The patients with high number of perilesional CD8+ T cells or high level of cytokines/chemokines were associated with poor re-pigmentation efficiency. For in-vitro experiments, we successfully isolated and characterized human DMSCs and skin-homing CD8+ T cells. We established DMSCs and CD8+ T cell co-culture system, where DMSCs possessed significant inhibitory effects against skin homing CD8+ T lymphocytes. DMSCs inhibited CD8+ T cells proliferation, induced them apoptosis and regulated their cytokines/chemokines production. Our results suggest that vitiligo patients’ autologous melanocytes transplantation efficiency might be predicted by perilesional skin-homing CD8+ T cell activities, and DMSCs might be used as auxiliary agent to improve transplantation efficacy.

[Impact on tyrosinase expression and export from endoplasmic reticulum by inhibition of 26S proteasome]

OBJECTIVE

To determine the impact on tyrosinase expression and export from endoplasmic reticulum by inhibition of 26S proteasome.

METHODS

Western blot was used to detect 26S proteasome from 8 vitiligo patients and 4 healthy controls. Melanocytes were incubated with proteasome inhibitor (lactacystin) and further detected as follows: cell survival by MTT assay, proteasome activity with fluorescence, ultrastructure observation with electron microscope, co-localization of tyrosinase and calreticulin (endoplasmic reticulum marker) by confocal laser scanning microscopy and 26S proteasome and tyrosinase with Western blot.

RESULTS

The 26S proteasome expression level from lesions of vitiligo (1.05 ± 0.40) was significantly lower than the donor sites (1.82 ± 0.88) and the healthy controls (1.88 ± 0.16) (P < 0.05). But no significant difference existed between the latter two groups (P > 0.05). Compared to the untreated group, a 12-h incubation of 10 µmol/L lactacystin showed inhibitory effects on melanocytes (0.999 ± 0.110 vs 1.372 ± 0.127, P < 0.05) and significantly decreased proteasome activity (0.234 ± 0.019 vs 1, P < 0.01). Expansion rate of endoplasmic reticulum in the lactacystin group (1.91 ± 0.17) was significantly higher than that of the untreated cells (1.17 ± 0.11) (P < 0.05). More tyrosinase co-localized with calreticulin in endoplasmic reticulum in lactacystin-treated cells was observed than that of the untreated group. Compared with the untreated group, significantly decreased levels of tyrosinase (146 ± 10 vs 269 ± 8, P < 0.01) and tyrosinase activity (0.159 ± 0.017 vs 0.221 ± 0.019, P < 0.01) were shown in the lactacystin group (P < 0.05).

CONCLUSIONS

Significantly decrease of 26S proteasome is found in lesions of vitiligo patients. Inhibition of 26S proteasome may lead to expansion of endoplasmic reticulum of melanocytes, impact export of tyrosinase from melanocyte endoplasmic reticulum and expression of tyrosinase.

Niacin protects against UVB radiation-induced apoptosis in cultured human skin keratinocytes

Niacin and its related derivatives have been shown to have effects on cellular activities. However, the molecular mechanism of its reduced immunosuppressive effects and photoprotective effects remains unclear. In this study, we investigated the molecular mechanism of the photoprotective effect of niacin in ultraviolet (UV)-irradiated human skin keratinocytes (HaCaT cells). We found that niacin effectively suppressed the UV-induced cell death and cell apoptosis of HaCaT cells. Existing data have shown that AKT activation is involved in the cell survival process. Yet, the potential mechanism of niacin in protection against UV-induced skin damage has thus far not fully been eluvidated. We observed that niacin pretreatment enhances UV induced activation of AKT (Ser473 phosphorylation) as well as that of the downstream signal mTOR (S6 and 4E-BP1 phosphorylation). The PI3K/AKT inhibitor, LY294002, and the mTOR inhibitor, rapamycin, largely neutralized the protective effects of niacin, suggesting that AKT and downstream signaling mTOR/S6 activation are necessary for the niacin-induced protective effects against UV-induced cell death and cell apoptosis. Collectively, our data suggest that niacin may be utilized to prevent UV-induced skin damage and provide a novel mechanism of its photoprotective effects against the UV radiation of sunlight by modulating both AKT and downstream mTOR signaling pathways.

Immunodetection of the MCHR1 antibody in vitiligo patient sera

Human vitiligo is an acquired depigmenting skin disorder characterized by milk-white skin macules resulting from a chronic and progressive loss of melanocytes. It has been suggested that autoimmune mechanisms are involved in this disorder. We undertook this project to obtain an MCHR1-C linear peptide containing four main MCHR1 B-cell epitopes in an attempt to detect the IgG antibody against MCHR1 in vitiligo. The target gene encoding the MCHR1-C peptide was cloned into a pGEX-4T-2 expression vector, expressed in Escherichia coli BL21, and purified using a GST column. The molecular weight was analyzed by SDS-PAGE and western blotting. The IgG antibody response to MCHR1 was detected by ELISA with MCHR1-C as a coated antigen, and the absorption experiment was used to assess the binding ability of the Ab detected by MCHR1-C with a membrane protein in human epidermal melanocytes. The purified peptide MCHR1-C with a molecular weight of 33 kDa was obtained, and could bind to the MCHR1 antibody in human sera. Of the vitiligo patient sera examined, 24 of 145 (16.55%) tested positive for the MCHR1 antibody, and the frequency in the vitiligo patient group was significantly greater compared to the normal control. However, no significant difference between gender, disease duration, clinical subtype or family history between the two groups was observed. In addition, the Ab detected by MCHR1-C in sera was specifically absorbed by the membrane protein obtained from human epidermal melanocytes. Collectively, our data suggest that the MCHR1-C peptide can be used to detect the MCHR1 antibody in vitiligo patients as a coated antigen instead of MCHR1 protein. We conclude that the level of MCHR1 antibody in active vitiligo patients is significantly higher than that in healthy individuals, while gender, disease duration, clinical subtype and family history have no association with the level of MCHR1 antibody in vitiligo patients.

[Expression of InnVit/FBXO11 in vitiligo and its role in tyrosinase export from endoplasmic reticulum]

OBJECTIVE

To investigate the roles of InnVit (FBX011) gene in melanocytes by detecting the expression of InnVit gene in vitiligo and analyzing the impact of InnVit gene on morphology of endoplasmic reticulum (ER) and the tyrosinase export from ER.

METHODS

The lesion tissues and the donor tissues were collected from 10 vitiligo patients to examine the InnVit gene expression by immunohistochemistry. Synthesized specific siRNA and constructed plasmid P3XF-P120 were separately transfected into cells for the silence and over-expression of InnVit gene with lipofectamine(TM) 2000. The untreated cells were used as control. Morphology of ER of cells from the above three groups was observed under electron microscope. Co-localization of tyrosinase and calreticulin was identified by confocal laser scanning microscopy. InnVit, tyrosinase and calreticulin were examined by Western blot.

RESULTS

In vitiligo patients, the expression of InnVit gene in the lesions was markedly lower than that in the donor tissues. The normal morphology of ER was found in the untreated and the plasmid groups whereas inflated ER was shown in siRNA group. And the relative inflation rate in siRNA group (1.97 +/- 0.48) was higher than that in the untreated group (1.28 +/- 0.09) and plasmid group (1.24 +/- 0.13) (both P = 0.001). In the untreated and the plasmid groups, tyrosinase was expressed beyond the scope marked by ER marker protein calreticulin partly, but co-localized with calreticulin in ER in the siRNA group. Western blot showed that, contrast to the untreated group (0.320 +/- 0.020), a lower expression level of InnVit in the siRNA group (0.030 +/- 0.004, P = 0.001) and a higher expression of InnVit in the plasmid group were shown (0.710 +/- 0.040, P = 0.001). No significant difference about the expression level of calreticulin was observed among the three groups (P > 0.05). As compared with the untreated group (0.350 +/- 0.030), a higher tyrosinase level in the siRNA group (1.040 +/- 0.060, P = 0.001) and in the plasmid group (0.720 +/- 0.030, P = 0.001) was found. And the former was higher than the latter (P = 0.001).

CONCLUSION

A lower expression of InnVit is observed in the lesion tissues than in the donor tissues from vitiligo patients. The InnVit gene can have an impact on the morphology of ER and tyrosinase export from ER. And it may further affect the function of melanocytes.

VIT1/FBXO11 knockdown induces morphological alterations and apoptosis in B10BR mouse melanocytes

It has been shown that the VIT1 gene is down-regulated in vitiligo melanocytes, but the expression of the VIT1 gene in melanocytes of Chinese patients with vitiligo and the potential function of VIT1 in pathogenesis of vitiligo are not as well known. In this study, we first compared VIT1 gene expression in melanocytes cultured from non-lesional skin of generalized vitiligo patients, normal melanocytes and melanomas in China. The cloned VIT1 ORF cDNA fragments were sequenced and then compared. VIT1 siRNAs were transfected into mouse B10BR melanocytes. The results from semi-quantitative RT-PCR demonstrated that the expression levels of VIT1 in non-lesional melanocytes from vitiligo patients are significantly lower than those in normal melanocytes. In contrast, the expression levels of VIT1 in melanoma are higher. The results also demonstrated that VIT1 is not a novel gene including a fragment of 81 bp flanking by consensus GT and AG sequences on the 5' and 3' ends, which is regarded as an intron. VIT1 without the extra intron is a known gene called FBXO11. Our findings revealed abnormal morphology by light and electron microscopes in FBXO11 siRNA transfected melancytes, which display large epithelioid perikaryon and stubby dendrites with occasional multidendricity as opposed to slender perikaryon and bipolar dendrites of controls. The electron microscopic observation indicated swelling mitochondria and endoplasmic reticulum (ER), and increased lysosomes and bubbles. Further, transfection of FBXO11 siRNA significantly promoted cell apoptosis. Collectively, this study provides comprehensive morphological proof of the relationship between dilation of ER and decreased levels of the FBXO11 gene in vitiligo melanocytes.

[Studies on protective monoclonal antibodies to Leishmania donovani]

Kala-azar is increasing in incidence in some endemic areas of China, such as provinces of Sichuan and Gansu. Monoclonal antibodies have been shown to interfere with the cutaneous leishmaniasis infection in the experimental animals. We have now raised McAb against membrane antigen of promastigotes of L. donovani canine isolate (the pathogen of visceral leishmaniasis). In this paper we report 3 McAb which inhibit the growth of promastigotes in vitro culture by incorporation of 3H-thymine deoxyriboside, such as McAb 2B12-A8, 2H6-E3, in the presence of complement, showing strong inhibiting effects with a decrease in incorporation of 3H-TdR, 94-99.3% rate of inhibition, whereas the inhibition rate induced by McAb 1B1-C2 fluctuated in a range of 68-95%, which is identical with the results of macrophage infection inhibition test by the same McAb, 61-87%. The results of ultrastructural localization of L. donovani antigen by protective McAb 2H6-E3 with immunogold technique showed the gold particles, in clumps, widely distributed on the outer side of promastigotes membrane. According to the high density of localized gold particles, it is suggested that this antigen is abundant on the plasma membrane.