Xiaoying Yuan

Effects and mechanisms of aloperine on 2, 4-dinitrofluorobenzene-induced allergic contact dermatitis in BALB/c mice

Allergic contact dermatitis is a prototypic T-cell-mediated cutaneous inflammatory response. Multiple cell types, inflammatory mediators and cytokines are involved in the regulation of immunologic and inflammatory processes in allergic contact dermatitis. Aloperine is an isolated alkaloid found in the plant of Sophora alopecuroides L. It has been clinically proved effective in China for a long time for skin inflammatory diseases such as allergic contact dermatitis. However, the mechanism of aloperine on allergic contact dermatitis is largely unknown. Therefore, the aim of this study was to investigate the effect of aloperine on 2, 4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis in BALB/c mice and the possible underlying mechanisms. The results showed that topical application of DNFB on the ear provoked typical allergic contact dermatitis with ear swelling and ear erythema in BALB/c mice. Treatments with 1% aloperine suppressed DNFB-induced increase in ear thickness and ear erythema. Moreover, 1% aloperine treatment significantly decreased the up-regulated mRNA and protein levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) induced by DNFB in ear biopsy homogenates. Our findings suggest that aloperine greatly improves the DNFB-induced allergic contact dermatitis in mice. The therapeutic mechanism might be related to the reduction of TNF-alpha, IL-1beta and IL-6 production induced by DNFB.

Silencing of GPNMB by siRNA Inhibits the Formation of Melanosomes in Melanocytes in a MITF-Independent Fashion

Background Melanosomes are specialized membrane-surrounded organelles, which are involved in the synthesis, storage and transport of melanin. Glycoprotein (transmembrane) non-metastatic melanoma protein b (GPNMB), a melanosome-specific structural protein, shares significant amino acid sequence homology with Pmel-17. Proteomic analysis demonstrated that GPNMB is present in all stages (I-IV) of melanosomes. However, little is known about the role of GPNMB in melanosomes. Methodology/Principal Findings Using real-time quantitative PCR, Western blotting and immunofluorescence analysis, we demonstrated that the expression of GPNMB in PIG1 melanocytes was up-regulated by ultraviolet B (UVB) radiation. Transmission electron microscopy analysis showed that the total number of melanosomes in PIG1 melanocytes was sharply reduced by GPNMB-siRNA transfection. Simultaneously, the expression levels of tyrosinase (Tyr), tyrosinase related protein 1 (Trp1), Pmel17/gp100 and ocular albinism type 1 protein (OA1) were all significantly attenuated. But the expression of microphthalmia-associated transcription factor (MITF) was up-regulated. Intriguingly, in GPNMB silenced PIG1 melanocytes, UVB radiation sharply reduced MITF expression. Conclusion Our present work revealed that the GPNMB was critical for the formation of melanosomes. And GPNMB expression down-regulation attenuated melanosome formation in a MITF-independent fashion.

Topical application of aloperine improves 2,4-dinitrofluorobenzene-induced atopic dermatitis-like skin lesions in NC/Nga mice

Aloperine has been shown to inhibit 2,4-dinitrofluorobenzene (DNFB) induced allergic contact dermatitis in BALB/c mice. In the present study, we further investigated the effect of aloperine on DNFB-induced atopic dermatitis-like skin lesions in NC/Nga mice. NC/Nga mice elicited atopic dermatitis-like skin lesions after the topical application of DNFB. Aloperine treatment significantly inhibited dermatitis index and ear thickness in DNFB-treated NC/Nga mice in a dose-dependent manner. Eosinophils, mast cells infiltration into the ears and plasma level of immunoglobulin (Ig) E were also suppressed by aloperine treatment. Finally, cytokine (interleukin (IL)-1β, IL-4, IL-6, IL-10, IL-13, tumor necrosis factor (TNF)-α and interferon (IFN)-γ) productions in ear biopsies homogenates were significantly elevated after DNFB challenge. Topical application of aloperine increased the immunosuppressive cytokine IL-10 level, while it reduced other cytokines production in a dose-dependent manner. Taken together, these data suggest that aloperine may be one of the effective therapeutic agents for the treatment of atopic dermatitis.

Curcumin improves the paclitaxel-induced apoptosis of HPV-positive human cervical cancer cells via the NF-κB-p53-caspase-3 pathway.

Paclitaxel, isolated from Taxus brevifolia, is considered to be an efficacious agent against a wide spectrum of human cancers, including human cervical cancer. However, dose-limiting toxicity and high cost limit its clinical application. Curcumin, a nontoxic food additive, has been reported to improve paclitaxel chemotherapy in mouse models of cervical cancer. However, the underlying mechanisms remain unclear. In this study, two human cervical cancer cell lines, CaSki [human papilloma virus (HPV)16-positive] and HeLa (HPV18-positive), were selected in which to investigate the effect of curcumin on the anticancer action of paclitaxel and further clarify the mechanisms. Flow cytometry and MTT analysis demonstrated that curcumin significantly promoted paclitaxel-induced apoptosis and cytotoxicity in the two cervical cell lines compared with that observed with paclitaxel alone (P<0.05). Reverse transcription-polymerase chain reaction indicated that the decline of HPV E6 and E7 gene expression induced by paclitaxel was also assisted by curcumin. The expression levels of p53 protein and cleaved caspase-3 were increased significantly in the curcumin plus paclitaxel-treated HeLa and CaSki cells compared with those in the cells treated with paclitaxel alone (P<0.01). Significant reductions in the levels of phosphorylation of IκBα and the p65-NF-κB subunit in CaSki cells treated with curcumin and paclitaxel were observed compared with those in cells treated with paclitaxel alone (P<0.05). This suggests that the combined effect of curcumin and paclitaxel was associated with the NF-κB-p53-caspase-3 pathway. In conclusion, curcumin has the ability to improve the paclitaxel-induced apoptosis of HPV-positive human cervical cancer cell lines via the NF-κB-p53-caspase-3 pathway. Curcumin in combination with paclitaxel may provide a superior therapeutic effect on human cervical cancer.

Erythroderma: A clinical-etiological study of 82 cases.

Erythroderma is an uncommon skin disorder characterized by generalized reddening and scaling of over 90% of the skin. It represents a maximal stage of skin irritation induced by several skin diseases such as psoriasis, contact dermatitis, drug reactions, and mycosis fungoides. Data including the clinical symptoms, laboratory examinations and skin biopsies were collected from 82 erythroderma patients admitted to our hospital in the period between Jan.1st, 2003 and Dec.31st, 2008. According to clinical findings, laboratory findings and biopsy results, the most common causative factors were pre-existing dermatoses (72.0%), followed by drug reactions (17.0%), idiopathic causes (6.1%) and malignancies (4.9%). Among the pre-existing dermatoses, psoriasis is the most common etiology (30.5%). We also found hypereosinophilic syndrome, sarcoidosis and dermatomyositis could be causes of erythroderma. In the drug-induced group, Chinese traditional herbal medicines were probably the most frequently implicated drugs in our series, with 9 of the 14 cases (64.3%). Follow-up information was obtained for 65 patients, and most of our patients had improved symptoms after treatment. In our series we found a high percentage of erythroderma secondary to pre-existing dermatoses and a low percentage of erythroderma secondary to malignancy. Among drugs as an etiological group, Chinese traditional herbal medicines were the most frequent drugs. From our follow-up study, the prognosis of most patients with erythroderma is relatively good.

Topical Grape Seed Proanthocyandin Extract Reduces Sunburn Cells and Mutant p53 Positive Epidermal Cell Formation, and Prevents Depletion of Langerhans Cells in an Acute Sunburn Model

OBJECTIVE The purpose of this study was to investigate whether grape seed proanthocyanidin extract (GSPE) can provide photoprotection against ultraviolet (UV) irradiation. BACKGROUND DATA Study has shown that GSPE is a natural oxidant, and is used in many fields such as ischemia-reperfusion injury, chronic pancreatitis, and even cancer. However, the effect of GSPE on UV irradiation is as yet unknown. METHODS Cutaneous areas on the backs of normal volunteers were untreated or treated with GSPE solutions or vehicles 30 min before exposure to two minimal erythema doses (MED) of solar simulated radiation. Cutaneous areas at different sites were examined histologically for the number of sunburn cells, or immunohistochemically for Langerhans cells and mutant p53 epidermal cells. RESULTS On histological and immunohistochemical examination, skin treated with GSPE before UV radiation showed fewer sunburn cells and mutant p53-positive epidermal cells and more Langerhans cells compared with skin treated with 2-MED UV radiation only (p<0.001, p<0.001, and p<0.01, respectively). CONCLUSIONS GSPE may be a possible preventive agent for photoprotection.

Effects of Intense Pulsed Light and Ultraviolet A on Metalloproteinases and Extracellular Matrix Expression in Human Skin

OBJECTIVE The aim of this study was to evaluate the effects of intense pulsed light (IPL) and ultraviolet A (UVA) irradiation on the expression of matrix metalloproteases (MMPs), tissue inhibitor of metalloproteinase 1 (TIMP-1), and extracellular matrix (ECM) in human skin, and to confirm the relative mechanism. BACKGROUND DATA IPL has been widely used to treat photoaged skin but the underlying mechanism remains unknown. METHODS Human buttock skin was irradiated by repetitive suberythemal doses of UVA and therapeutic doses of IPL. Skin biopsies were taken and the protein/mRNA expression of MMP-1, -3, -9, and -12 and TIMP-1 was examined by immunohistochemistry, image analysis, and real-time quantitative polymerase chain reaction (qRT-PCR). RESULTS Compared with normal control skin, both IPL and UVA irradiation induced a general elevation of MMP-1, -3, -9, and -12 and TIMP-1 at protein/mRNA levels, with some differences in the MMP expression patterns, e.g., a remarkable increase of MMP-1, -3, and -12 in UVA-exposed skin, while lower MMP-1, -3, and -12 (p < 0.01, p < 0.01, p < 0.01) but higher MMP-9 (p < 0.05) levels in IPL-irradiated skin. Meanwhile, increased collagen I fibers (p < 0.05) were observed in IPL-irradiated skin, whereas fragments of elastic fibers were found in UVA-exposed skin. CONCLUSION These findings demonstrated that IPL has similar effects on the expression of MMPs/TIMP-1 in human skin to UVA, but the expression pattern differed from that in UVA-exposed skin, which may account for IPLs photorejuvenation effects.

Endothelin-1 enhances the melanogenesis via MITF-GPNMB pathway.

Endothelin-1 (ET-1) plays an indispensable role in epidermal pigmentation in hyperpigmentary disorders due to a central role in melanogenesis. Nevertheless, precise mechanism involved in ET-1-induced hyperpigmentation is still undefined. Glycoprotein (transmembrane) non-metastatic melanoma protein b (GPNMB) is a key element in melanosome formation. Therefore, we speculated that GPNMB was correlated with ET-1-induced pigmentation. After culturing with ET-1, melanin synthesis was significantly up-regulated, accompanying with increased expression of GPNMB and microphthalmia-associated transcription factor (MITF). Total number of melanosomes and melanin synthesis were sharply reduced via GPNMB-siRNA transfection, indicating ET-1-induced pigmentation by GPNMB-dependent manner. Furthermore, MITFsiRNA transfection strikingly inhibited GPNMB expression and the melanogenesis, and this suppression failed to be alleviated by ET-1 stimulation. All of these results demonstrated that ET-1 can trigger melanogenesis via the MITF-regulated GPNMB pathway. Taken together, these findings will provide a new explanation of how ET-1 induces hyperpigmentation, and possibly supply a new strategy for cosmetic studies. [BMB Reports 2013; 46(7): 364-369]

Cutis laxa: analysis of metalloproteinases and extracellular matrix expression by immunohistochemistry and histochemistry

Upregulation of matrix metalloproteinases (MMPs) and downregulation of tissue inhibitors of metalloproteinases (TIMP) have been reported in cultured fibroblasts from patients with congenital cutis laxa (CL) or anetoderma. We determined the protein expressions of MMP-1, MMP-2, MMP-3, MMP-9, MMP-12, TIMP-1 and collagen I, collagen III in vivo, to confirm their roles in the pathogenesis of cutis laxa. The protein expression of the MMPs and collagens from skin lesions of CL were detected by immunohistochemistry and analyzed by image analysis software. Markedly increased MMP-1, MMP-2, MMP-3, MMP-9, MMP-12, TIMP-1 associated with alteration of elastic and collagen fibers were found in two cases of CL, whereas increased MMP-3, MMP-9, MMP-12 accompanying a degradation of elastic fibers were detected in the third case. These results suggest an elevated expression of MMPs may play a role in the evolution or genesis of CL.

Effect of topical calcineurin inhibitors as monotherapy or combined with phototherapy for vitiligo treatment: a meta‐analysis

Vitiligo is a common skin disease for which immunomodulating calcineurin inhibitors have been considered reasonable treatment. We searched the MEDLINE, Embase, and Cochrane central register of controlled trials databases for articles published prior to September 2014. Thirteen studies were included in the meta‐analysis. After pooling the trials, we concluded that calcineurin inhibitors showed a better therapeutic effect on vitiligo than placebo, according to lesion report (RR = 2.62, 95%CI, 1.39–4.93, p = 0.003) and patient report (RR = 1.42, 95%, 0.87–2.31, p = 0.157). Subgroup analysis was performed to determine whether the combination with phototherapy was a source of heterogeneity. The trial sequence analysis indicated that the results of combined therapy by lesion report were reliable and conclusive. However, in the patient report trials, the frequency of lesions on the hand and foot was higher, and the effect of combined therapy was still not significant. Calcineurin inhibitors showed a better therapeutic effect than placebo in the treatment of vitiligo with phototherapy. However, the typical UV‐resistant sites (i.e., hand and foot) were still difficult to cure even with combined therapy. Because of concerns about photocarcinogenesis, the clinical application of combined therapy should be explored with caution.