Xiao-Yong Man

Overexpression of vascular endothelial growth factor (VEGF) receptors on keratinocytes in psoriasis: regulated by calcium independent of VEGF.

Psoriasis is a common chronic inflammatory disease of the skin characterized by epidermal hyperplasia and angiogenesis. Recently, vascular endothelial growth factor receptors (VEGFRs, including VEGFR‐1, VEGFR‐2 and VEGFR‐3) were found to be expressed in normal human epidermis and associated with proliferation and migration of keratinocytes. The purpose of this study is to investigate the expression of VEGFRs on psoriatic keratinocytes and the roles of calcium and VEGF in regulating VEGFR expression. Skin samples from 17 patients with chronic plaque psoriasis and 11 normal controls were included. The expression of VEGFRs in psoriatic keratinocytes at mRNA and protein levels was determined by reverse transcriptase‐polymerase chain reaction (RT‐PCR) and Western blot analysis. Localization of the VEGFRs in skin lesions was determined by immuno‐fluorescent method. Since keratinocyte proliferation and differentiation rely on calcium concentrations, and VEGF is overexpressed in psoriatic epidermis, we further investigated the roles of calcium and VEGF in regulating the expression of VEGFRs. Overexpression of VEGFR‐1, VEGFR‐2 and VEGFR‐3 in psoriatic epidermis was demonstrated both at mRNA and protein levels in vitro. VEGFRs were strongly labeled in non‐lesional, perilesional and lesional psoriatic keratinocytes in all viable epidermal stratums in vivo. Furthermore, both exogenous VEGF165 and calcium enhanced the expression of VEGFRs. Calcium also enhanced the expression of VEGF in non‐lesional psoriatic keratinocytes, while targeted blockade of VEGF activity by bevacizum‐ab could not inhibit calcium‐induced up‐regulation of protein levels of VEGFRs. We conclude from these results that VEGFRs are overexpressed in lesional psoriatic epidermal keratinocytes. Both calcium and VEGF regulate VEGFRs expression in psoriatic epidermis. More importantly, calcium is a potential regulator for VEGFR independent of VEGF.

VEGF induces proliferation of human hair follicle dermal papilla cells through VEGFR-2-mediated activation of ERK

Vascular endothelial growth factor (VEGF) is one of the strongest regulators of physiological and pathological angiogenesis. VEGF receptor 2 (VEGFR-2), the primary receptor for VEGF, is thought to mediate major functional effects of VEGF. Previously, we have localized both VEGF and VEGFR-2 in human hair follicles. In this study, we further defined the expression and roles of VEGFR-2 on human hair follicle dermal papilla (DP) cells. The expression of VEGFR-2 on DP cells was examined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis separately, and localization of VEGFR-2 was defined by immunofluorescence. The effect of VEGF on DP cells was analyzed by MTT assays and specific inhibitors. Finally, the role of VEGF involved in the signaling pathways was investigated by Western blot. RT-PCR and Western blot analysis demonstrated the expression of VEGFR-2 on DP cells. Immunostaining for VEGFR-2 showed strong signal on cultured human DP cells in vitro. Exogenous VEGF(165) stimulated proliferation of DP cells in a dose-dependent manner. Furthermore, this stimulation was blocked by a VEGFR-2 neutralizing antibody (MAB3571) and an ERK inhibitor (PD98059). VEGF(165)-induced phosphorylation of ERK1/2 was abolished by MAB3571 and PD98059, while the phosphorylation of p38, JNK and AKT were not changed by VEGF(165). Taken together, VEGFR-2 is expressed on primary human hair follicle DP cells and VEGF induces proliferation of DP cells through VEGFR-2/ERK pathway, but not p38, JNK or AKT signaling.

Expression and localization of vascular endothelial growth factor and vascular endothelial growth factor receptor-2 in human epidermal appendages: a comparison study by immunofluorescence

Background.  Vascular endothelial growth factor (VEGF) promotes angiogenesis and plays important roles in neovascularization and development of tissues. VEGF receptors (VEGFRs) are high‐affinity receptors for VEGF and are originally considered specific to endothelial cells. We have previously shown that keratinocytes from human normal skin express VEGFRs. This poses the question of whether these receptors are also expressed by epidermal appendages, as epidermal appendages are lined with epithelial cells.

Impaired nuclear translocation of glucocorticoid receptors: novel findings from psoriatic epidermal keratinocytes

Psoriasis is a chronic proliferative skin disease and is usually treated with topical glucocorticoids, which act through the glucocorticoid receptor (GR), a component of the physiological systems essential for immune responses, differentiation, and homeostasis. To investigate the possible role of GR in the pathogenesis of psoriasis, normal and psoriatic lesional skin were recruited. Firstly, the immunolocalization of GR in the skin and cultured epidermal keratinocytes were determined by immunofluorescence. In normal skin and cultured human epidermal keratinocytes, intracellular GR is localized in the nuclei, while in psoriatic skin and cultured keratinocytes, GR is in the cytoplasm. Next, we investigated possible factors associated with the cytoplasmic distribution. We found that VEGF and IFN-γ led to impaired nuclear translocation of GR through p53 and microtubule-inhibitor, vincristine, and inhibited nuclear uptake of GR in normal keratinocytes. In addition to dexamethasone, interleukin (IL)-13 was also able to transfer GR into nuclei of psoriatic keratinocytes. Furthermore, discontinuation of dexamethasone induced cytoplasmic retention of GR in normal keratinocytes. In contrast, energy depletion of normal epidermal keratinocytes did not change the nuclear distribution of GR. To confirm our findings in vivo, an imiquimod-induced psoriasis-like skin mouse model was included. IL-13 ameliorated (but vincristine exacerbated) the skin lesions on the mouse. Taken together, our findings define that impaired nuclear translocation of GR is associated with VEGF, IFN-γ, p53, and microtubule. Therapeutic strategies designed to accumulate GR in the nucleus, such as IL-13, may be beneficial for the therapy of psoriasis.

Role of endothelin-1 in the skin fibrosis of systemic sclerosis

Endothelin-1 (ET-1) acts as a key regulator of vasoconstriction and fibrosis. Many previous studies have focused on the role of ET-1 in scleroderma (systemic sclerosis, SSc).We investigated the effects of ET-1 on the production of extracellular matrix in SSc and normal skin fibroblasts. Primary cultured dermal fibroblasts from SSc patients and healthy controls were treated with ET-1 (25 ng/mL) for 0 min, 15 min, 1 h, 24 h, 48 h and 72 h, respectively. Our results showed that, in SSc fibroblasts, ET-1 upregulated collagen type I, connective tissue growth factor (CTGF), type I plasminogen activator inhibitor (PAI-1) and pAkt in a time-dependent manner within 72 h; in normal fibroblasts, 25 ng/mL ET-1 stimulation correlated with high levels of CTGF, PAI-1 and pAkt. The secretion of fibronectin (FN), collagen type I, and PAI-1 is markedly increased in the supernatant of both SSc fibroblasts and normal fibroblasts. Furthermore, ET-1 phosphorylates Smad2 and Smad3 in normal fibroblasts, but not in SSc fibroblasts. In conclusion, our results demonstrated that ET-1 may induce fibrosis in dermal fibroblasts through Akt signals.

Regulation of Involucrin in Psoriatic Epidermal Keratinocytes: The Roles of ERK1/2 and GSK-3β

Psoriasis, a common inflammatory skin disease, is characterized by epidermal hyperplasia, abnormal differentiation, angiogenesis, immune activation, and inflammation. Involucrin is an early terminal differentiation marker of epidermal keratinocytes. In this study, we determined the immunolocalization of involucrin in psoriatic lesions and normal skin of individuals without psoriasis by means of immunofluorescence (IF) assay. Furthermore, the regulation of involucrin by interleukin (IL)-13, IL-17A, endothelin (ET)-1, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ was investigated by Western blot. Extracellular regulate protein kinases 1/2 (ERK1/2) and glycogen syntheses kinase-3β (GSK-3β) inhibitors were also included to define the roles of these signals in the production of involucrin in both psoriatic and normal keratinocytes. In psoriatic lesional skin, involucrin was detected in the stratum spinosum, but not in the basal or the cornified layer. In normal skin, involucrin was restricted to the granular layer and the upper stratum spinosum. IL-13, IL-17A, ET-1, TNF-α, and IFN-γ up-regulate expression of involucrin in both psoriatic and normal keratinocytes. However, this effect was abolished by ERK1/2 and GSK-3β inhibitors. In conclusion, involucrin is up-regulated in psoriatic keratinocytes. IL-13, IL-17A, ET-1, TNF-α, and IFN-γ could increase involucrin protein levels in psoriatic and normal keratinocytes. The ERK1/2 and GSK-3β signaling pathways may play positive roles in regulating epidermal differentiation as observed in psoriasis.

VEGF upregulates VEGF receptor-2 on human outer root sheath cells and stimulates proliferation through ERK pathway.

Vascular endothelial growth factor (VEGF) is a key regulator of physiological and pathological angiogenesis. The biological effects of VEGF are mediated by receptor tyrosine kinases. VEGF receptor-2, the primary receptor for VEGF, is thought to mediate most functional effects. In this study, we examined the expression and roles of VEGF receptor-2 on human outer root sheath cells (ORS). The expression of VEGFR-2 was determined at mRNA and protein levels by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Localization of VEGFR-2 in ORS cells was detected by immunofluorescence. The effect of VEGF on ORS cell proliferation was determined by MTT assays. Our data showed the expression of VEGFR-2 on ORS cells at both mRNA and protein levels. Immunostaining for VEGFR-2 demonstrated strong signal on cultured ORS cells. Exogenous VEGF165 stimulated proliferation of ORS cells and upregulated expression of VEGFR-2 in a dose-dependent manner. Moreover, VEGF165 induced phosphorylation of VEGFR-2, PLC-γ1, PKC-α, MEK, and p44/42 MAPK (ERK1/2) in a time-dependent manner. Taken together, human ORS cells express functional VEGF receptor-2 and exogenous VEGF165 upregulates expression of VEGFR-2 and stimulates proliferation of ORS cells via VEGFR-2 mediated ERK signaling pathway.

Analysis of epithelial–mesenchymal transition markers in psoriatic epidermal keratinocytes

Psoriasis is similar to endpoints of epithelial–mesenchymal transition (EMT), a process of epithelial cells transformed into fibroblast-like cells. The molecular epithelial and mesenchymal markers were analysed in psoriatic keratinocytes. No obvious alteration of epithelial markers E-cadherin (E-cad), keratin 10 (K10), K14 and K16 was detected in psoriatic keratinocytes. However, significantly increased expression of Vim, FN, plasminogen activator inhibitor 1 (PAI-1) and Slug was seen. IL-17A and IL-13 at 50 ng ml−1 strongly decreased expression of K10, Vim and FN. TGF-β1 at 50 ng ml−1 promoted the production of N-cad, Vim, FN and PAI-1. Slug was decreased by dexamethasone (Dex), but E-cad was upregulated by Dex. Silencing of ERK partially increased E-cad and K16, but remarkably inhibited K14, FN, Vim, β-catenin, Slug and α5 integrin. Moreover, inhibition of Rho and GSK3 by their inhibitors Y27632 and SB216763, respectively, strongly raised E-cad, β-catenin and Slug. Dex decreased Y27632-mediated increase of β-catenin. Dex at 2.0 µM inhibited SB216763-regulated E-cad, β-catenin and slug. In conclusion, EMT in psoriatic keratinocytes may be defined as an intermediate phenotype of type 2 EMT. ERK, Rho and GSK3 play active roles in the process of EMT in psoriatic keratinocytes.

Multiple plexiform schwannoma of a finger.

ejd.2011.1609 Auteur(s) : Jiong Zhou, Xiao-Yong Man, Min Zheng, Sui-Qing Cai cai.suiqing@gmail.com Department of Dermatology, Second Affiliated Hospital, Hangzhou 310009, China Schwannomas are benign neurogenic tumors, first described by Verocay in 1908 [1]. There are 7 subtypes: classical (Verocay), cranial nerve, cellular, plexiform, degenerated (ancient), melanotic, and granular cell schwannoma [2]. Plexiform schwannoma is a rare subtype, accounting for approximately 5% of schwannomas [2]. Sometimes, [...]

Rottlerin as a therapeutic approach in psoriasis: Evidence from in vitro and in vivo studies

Rottlerin is a natural polyphenolic compound that was initially indicated as a PKCδ inhibitor. However, it was recently revealed that it may target a number of molecules and have biological effects on various cell types and is considered as a possible agent for tumor and cell proliferative diseases. Psoriasis is a chronic inflammatory cutaneous disorder with undefined etiology and is characterized by abnormal cellular proliferation, angiogenesis, and inflammation. Therefore, this paper investigates the regulatory effects of rottlerin on normal human epidermal keratinocytes (NHEKs) and imiquimod (IMQ)-induced psoriasiform (IPI) lesions. In vitro results showed that rottlerin inhibited cell proliferation in NHEKs through growth arrest and NFκB inhibition. It may also induce apoptosis in an autophagy-dependent pathway. We found that rottlerin inhibited human microvascular endothelial cells tube formation on matrigel. Rottlerin also decreased the cell senescence of keratinocytes and intracellular ROS generation, which indicated its antioxidant effect. We also showed that rottlerin affects the expression of keratinocyte proliferation biomarkers. In 12-O-tetradecanoylphorbol13-acetate (TPA)–induced keratinocytes, rottlerin significantly inhibited the expression of the induced pro-inflammatory cytokines in keratinocytes. An animal experiment provided the corresponding evidence based on this evidence in vitro, by using IPI model, we found that rottlerin could relieve the psoriasiform of BALB/c mice by inhibiting keratinocyte proliferation, inflammatory cell infiltration, and vascular proliferation. In conclusion, our results suggest that rottlerin may prove useful in the development of therapeutic agents against psoriasis. However, the deep mechanism still requires further study.