Molecular Mechanisms and Management of a Cutaneous Inflammatory Disorder: Psoriasis.

Psoriasis is a complex chronic inflammatory cutaneous disorder. To date, robust molecular mechanisms of psoriasis have been reported. Among diverse aberrant immunopathogenetic mechanisms, the current model emphasizes the role of Th1 and the IL-23/Th17 axis, skin-resident immune cells and major signal transduction pathways involved in psoriasis. The multiple genetic risk loci for psoriasis have been rapidly revealed with the advent of a novel technology. Moreover, identifying epigenetic modifications could bridge the gap between genetic and environmental risk factors in psoriasis. This review will provide a better understanding of the pathogenesis of psoriasis by unraveling the complicated interplay among immunological abnormalities, genetic risk foci, epigenetic modification and environmental factors of psoriasis. With advances in molecular biology, diverse new targets are under investigation to manage psoriasis. The recent advances in treatment modalities for psoriasis based on targeted molecules are also discussed.

Analysis of apoptosis-associated molecules Erythroid differentiation regulator 1, bcl-2 and p53 in actinic keratosis after treatment with ingenol mebutate.

Actinic keratosis (AK) is the most common cutaneous premalignant neoplasm precursor of malignant skin tumors. The aberrant apoptotic pathway is thought to be associated with pathogenesis of AK. Ingenol mebutate has been shown to be effective and safe for treatment of AK. However, the effect of ingenol mebutate on apoptosis-related molecules using human skin samples has not been studied well. Erythroid differentiation regulator 1 (Erdr1) was recently reported to play a crucial role in malignant skin cancers like malignant melanoma. The role of Erdr1 in premalignant actinic keratosis (AK) has not been explored. The purpose of this study was to investigate whether the expression of apoptosis-associated molecules such as Erdr1, p53 and bcl-2 was affected by the treatment of ingenol mebutate in AK. Nine patients with AK underwent skin biopsy at baseline and 8 weeks after treatment with ingenol mebutate for immunohistochemical evaluation with Erdr1, p53 and bcl-2. In addition, skin samples from five control subjects were retrieved. Upregulation of Erdr1 and a significant decrease in expression of p53 and bcl-2 were observed after treatment with ingenol mebutate. Ingenol mebutate treatment for AK resulted in the modulation of apoptosis-associated molecules with an increase in the expression of Erdr1 and a decrease in the expression of p53 and bcl-2.

Erythroid Differentiation Regulator 1 as a Novel Biomarker for Hair Loss Disorders.

Erythroid differentiation regulator 1 (Erdr1) is known to be involved in the inflammatory process via regulating the immune system in many cutaneous disorders, such as psoriasis and rosacea. However, the role of Erdr1 in various hair loss disorders remains unclear. The aim of this study was to investigate the putative role of Erdr1 in alopecias. Skin samples from 21 patients with hair loss disorders and five control subjects were retrieved, in order to assess their expression levels of Erdr1. Results revealed that expression of Erdr1 was significantly downregulated in the epidermis and hair follicles of patients with hair loss disorders, when compared to that in the control group. In particular, the expression of Erdr1 was significantly decreased in patients with alopecia areata. We propose that Erdr1 downregulation might be involved in the pathogenesis of hair loss, and could be considered as a novel biomarker for hair loss disorders.

Rosacea: Molecular Mechanisms and Management of a Chronic Cutaneous Inflammatory Condition.

Rosacea is a chronic cutaneous inflammatory disease that affects the facial skin. Clinically, rosacea can be categorized into papulopustular, erythematotelangiectatic, ocular, and phymatous rosacea. However, the phenotypic presentations of rosacea are more heterogeneous. Although the pathophysiology of rosacea remains to be elucidated, immunologic alterations and neurovascular dysregulation are thought to have important roles in initiating and strengthening the clinical manifestations of rosacea. In this article, we present the possible molecular mechanisms of rosacea based on recent laboratory and clinical studies. We describe the genetic predisposition for rosacea along with its associated diseases, triggering factors, and suggested management options in detail based on the underlying molecular biology. Understanding the molecular pathomechanisms of rosacea will likely aid toward better comprehending its complex pathogenesis.

Molecular Mechanisms of Cutaneous Inflammatory Disorder: Atopic Dermatitis.

Atopic dermatitis (AD) is a multifactorial inflammatory skin disease resulting from interactions between genetic susceptibility and environmental factors. The pathogenesis of AD is poorly understood, and the treatment of recalcitrant AD is still challenging. There is accumulating evidence for new gene polymorphisms related to the epidermal barrier function and innate and adaptive immunity in patients with AD. Newly-found T cells and dendritic cell subsets, cytokines, chemokines and signaling pathways have extended our understanding of the molecular pathomechanism underlying AD. Genetic changes caused by environmental factors have been shown to contribute to the pathogenesis of AD. We herein present a review of the genetics, epigenetics, barrier dysfunction and immunological abnormalities in AD with a focus on updated molecular biology.

IL-18 and Cutaneous Inflammatory Diseases.

Interleukin (IL)-18, an IL-1 family cytokine, is a pleiotropic immune regulator. IL-18 plays a strong proinflammatory role by inducing interferon (IFN)-γ. Previous studies have implicated IL-18 in the pathogenesis of various diseases. However, it is not well understood biologic activities of IL-18 in the diverse skin diseases. Here, we have reviewed the expression and function of IL-18 in skin diseases including inflammatory diseases. This article provides an evidence-based understanding of the role of IL-18 in skin diseases and its relationship with disease activities.

Corticotropin-releasing factor induces immune escape of cervical cancer cells by downregulation of NKG2D.

Corticotropin-releasing factor (CRF), a coordinator of the body's responses to stress, is found in various cancer tissues and cell lines. However, the exact abilities of CRF to manipulate natural killer (NK) cells during immune response have not been studied. NKG2D is an activating receptor that is expressed on most NK and CD8+ T cells. MHC class I-related chain A (MICA) and UL16-binding protein (ULBP) 1, 2 and 3 are well-known ligands for NKG2D. In the present study, we reported our findings regarding the role of CRF in cervical cancer cell survival. Human cervical cancer cell line, HeLa cells, had significantly higher intracellular expression of UL16-binding protein 2 (ULBP2) following CRF treatment but had only slightly increased surface expression of ULBP2. Notably, MMPi (pan-metalloproteases inhibitor) blocked the release of ULBP2 molecules from the surface of HeLa cells. Furthermore, incubating NK cells with culture supernatants from CRF-treated HeLa cells, which contained soluble NKG2D ligand, reduced NK cell activity by decreasing surface expression of NKG2D. Collectively, downregulation of NKG2D by CRF-induced soluble NKG2D ligand provides a potential mechanism by which cervical cancer cells escape NKG2D-mediated attack under stress conditions.

Melphalan-induced apoptosis of EBV-transformed B cells through upregulation of TAp73 and XAF1 and nuclear import of XPA.

Melphalan (Mel) is widely used to treat patients with hematologic cancer, including multiple myeloma, but its mechanism of action in EBV-transformed B cells is poorly described. In this study, we demonstrate a novel mechanism by which transcriptionally active p73 (TAp73) induces translocation of X-linked inhibitor of apoptosis protein-associated factor 1 (XAF1) and xeroderma pigmentosum group A (XPA) during apoptosis caused by Mel treatment. We observed that Mel induced significant generation of reactive oxygen species (ROS) and subsequent apoptosis, as well as an early phosphorylation of p38 MAPK that preceded expression of the mitochondria membrane potential disruption-related molecules and the cleavage of caspases. In particular, Mel led to upregulation of TAp73, XAF1, and Puma and induced XPA nuclear import and translocation of Bax into mitochondria. Mel-induced apoptosis was inhibited by pretreatment with the ROS scavenger 4-amino-2,4-pyrrolidine-dicarboxylic acid (APDC) and the p38 MAPK inhibitor SB203580. We supposed that ROS generation might be the first event in Mel-induced apoptosis, because APDC blocked the increase in ROS, p38 MAPK, and TAp73, but SB203580 did not block ROS generation. Moreover, Mel elicited activation of ATR, and APDC inhibited phosphorylation of ATR but not SB203580. APDC and SB203580 completely blocked XPA and Bax translocation. We conclude that Mel promotes TAp73-mediated XAF1 and Puma expression via ROS generation and ATR/p38 MAPK pathway activation, thereby triggering apoptosis. Our results provide evidence of a novel alternate regulatory mechanism of TAp73 and reveal that Mel may be a therapeutic drug for curing EBV-related malignancies.

CD80 (B7.1) and CD86 (B7.2) induce EBV-transformed B cell apoptosis through the Fas/FasL pathway.

CD80 and CD86 expression is strongly regulated in B cells and is induced by various stimuli (e.g., cytokines, ligation of MHC class II and CD40 ligand). Epstein-Barr virus (EBV) infection activates B lymphocytes and transforms them into lymphoblastoid cells. However, the role of CD80 and CD86 in EBV infection of B cells remains unclear. Here, we observed that cross-linking of CD80 and CD86 in EBV-transformed B cells induced apoptosis through caspase-dependent release of apoptosis-related molecules, cytochrome c and apoptosis-inducing factor (AIF) from mitochondria, because Z-VAD-fmk (N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone) and N-acetylcysteine (NAC) blocked apoptosis and disruption of mitochondria. Stimulation of CD80 and CD86 induced expression of Fas ligand (FasL) on EBV-transformed B cells and upregulated Fas and FasL expression in IM-9 cells. Apoptosis through Fas-FasL interactions was blocked by treatment of cells with ZB4, an antagonistic anti-Fas antibody. These results suggest that the co-stimulatory molecules CD80 and CD86 induced by EBV infection stimulate apoptosis of EBV-transformed lymphoblastoid B cells via the Fas/FasL pathway.

The combination of DHEA, histamine, and insulin increases adipogenic differentiation and enhances tissue transplantation outcome in mice.

Adipose stem cells (ASCs) are pluripotent cells that can generate pure fat tissue for regeneration. Differentiated adipose cells have been generated by a common inducer cocktail composed of dexamethasone, insulin, and isobutylmethylxanthine (DIM). The major drawbacks of adipose cells are their tendency to float on the culture media and their cost. To overcome some of these disadvantages, a new inducer cocktail that includes insulin, dehydroepiandrosterone, and histamine (DH IH) was tested. As a result, lipid accumulation was elevated more than twofold with DH IH than with DIM. Cell adhesion and viability, which are important factors for stable differentiation, were increased with DH IH and were proven through measurement of mRNA expression levels of adhesion marker genes, N-cadherin and vascular cell adhesion molecule, as well as through an alamar blue assay. The expression of adipogenesis-related genes, adiponectin, and glucose transporter type 4 lasted for a long time. To improve the efficiency of grafting, cell adhesion and neovascularization need to be increased. Neovascularization was observed around the transplanted adipose cells, which showed a higher number of vessel formation in DH IH than in DIM. The above results suggest that DH IH can produce pure differentiated adipose cells effectively and enhance their adhesion onto the target location when these differentiated adipose cells were applied as a clinical resource.

Expression of hypothalamic-pituitary-adrenal axis in common skin diseases: evidence of its association with stress-related disease activity.

Hypothalamic-pituitary-adrenal (HPA) axis hormones and their receptors expressed in the skin are known to function locally, but how these hormones affect the maintenance of skin homeostasis or the pathogenesis of skin diseases is not fully understood. We comprehensively reviewed the distribution and function of the central and peripheral HPA axis in various stress-related skin diseases. Previous studies have shown altered expression of central and peripheral HPA axis hormones in chronic inflammatory skin diseases and skin tumours, and that hyper-active lesional HPA axis hormones may negatively feedback to the central HPA axis and interact with some cytokines and neuropeptides, leading to symptom deterioration. This provides an evidence-based understanding of the expression of the central and peripheral HPA axis in common skin diseases and its association with disease activity.

Association between single nucleotide polymorphisms of the transient receptor potential vanilloid 1 (TRPV-1) gene and patients with irritable bowel syndrome in Korean populations.

BACKGROUND AND STUDY AIMS: Transient receptor potential vanilloid type 1 (TRPV1) plays a crucial role in pain perception and its expression is up-regulated in patients with irritable bowel syndrome (IBS). The aim of this study was to investigate the potential association between Single nucleotide polymorphism (SNPs) of the TRPV-1 gene and patients with IBS. PATIENTS AND METHODS: We chose to focus on three SNPs in the human TRPV1 coding region (rs222749, rs9894618 and rs222747) in 80 healthy controls and 103 IBS patients. We developed the high resolution melting (HRM) method to determine the genotyping of rs222747 and rs9894618 and the genotyping of rs222749 was also determined by direct sequencing method. RESULTS: The CG genotype of rs222747 was 58.8% in controls and 45.6% in the IBS group. The GG genotype of rs222747 was 15.0% in controls and 20.4% in the IBS group. The CT genotype of rs222749 was 313% in controls and 32.0% in the IBS group. The CC genotype of rs9894618 was 98.8% in controls and 100.0% in the IBS group. There was no significant difference in allele frequency of these three SNPs of the TRPV1 gene between controls and the IBS group. Also, no significant difference was observed between the IBS subtypes. CONCLUSIONS: These results suggest that the SNPs of the TRPV1 gene may not be associated with IBS in Korean populations. Further studies with large cases are needed to validate the results of the present study.

Reactive oxygen species and p38 MAPK regulate Bax translocation and calcium redistribution in salubrinal-induced apoptosis of EBV-transformed B cells.

Salubrinal is a specific eIF2α phosphatase inhibitor that inhibits ER stress-mediated apoptosis. However, maintaining hyper-phosphorylated eIF2α state with high doses of salubrinal treatment promotes apoptosis in some cancer cells. In this report, we found that salubrinal induced apoptosis of EBV-transformed B cells. Notably, salubrinal induced ROS generation and p38 MPAK activation, which then induced expression of FasL. Moreover, salubrinal subsequently led to activation of caspases, calcium redistribution, Bax translocation, cytochrome c release, and apoptosis. These findings suggest that salubrinal may be a novel therapeutic approach for EBV-associated malignant diseases.

Erythroid differentiation regulator 1 (Erdr1) is a proapototic factor in human keratinocytes.

Skin is constantly exposed to physical and chemical stressors. The exposure of keratinocytes to ultraviolet B (UVB) irradiation causes epidermal damage via induction of apoptosis. Erythroid differentiation regulator 1 (Erdr1) modulates growth and survival of cells under various stressful conditions, but the function of Erdr1 in human keratinocyte apoptosis has not been investigated so far. Here, we investigated the effect of Erdr1 on UVB-induced apoptosis in human keratinocytes and also examined the underlying regulatory mechanism. First, Erdr1 expression was detected in human primary keratinocytes and normal human skin tissues. Expression of Erdr1 was enhanced in human keratinocytes following UVB irradiation. Knock-down of Erdr1 led to resistance to UVB-induced apoptosis. Also, Erdr1 overexpression increased UVB-induced apoptosis and induced caspase-3 activation. Furthermore, the extracellular signal-regulated kinase (ERK) inhibitor PD98059 and the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 significantly reduced Erdr1 expression following UVB irradiation. These results indicate that UVB induces Erdr1 via a MAPK-dependent mechanism. Taken together, these findings suggest that Erdr1 has a role as a proapoptotic factor in human keratinocytes and acts via ERK and p38 MAPK pathways. Therefore, Erdr1 may be a potential therapeutic target to reduce apoptosis in keratinocytes in conditions such as psoriasis and skin cancer.

Black tea extract prevents lipopolysaccharide-induced NF-κB signaling and attenuates dextran sulfate sodium-induced experimental colitis.

BACKGROUND: Black tea has been shown to elicit anti-oxidant, anti-carcinogenic, anti-inflammatory and anti-mutagenic properties. In this study, we investigated the impact of black tea extract (BTE) on lipopolysaccharide (LPS)-induced NF-κB signaling in bone marrow derived-macrophages (BMM) and determined the therapeutic efficacy of this extract on colon inflammation. METHODS: The effect of BTE on LPS-induced NF-κB signaling and pro-inflammatory gene expression was evaluated by RT-PCR, Western blotting, immunofluorescence and electrophoretic mobility shift assay (EMSA). The in vivo efficacy of BTE was assessed in mice with 3% dextran sulfate sodium (DSS)-induced colitis. The severity of colitis was measured by weight loss, colon length and histologic scores. RESULTS: LPS-induced IL-12p40, IL-23p19, IL-6 and IL-1ß mRNA expressions were inhibited by BTE. LPS-induced IκBα phosphorylation/degradation and nuclear translocation of NF-κB/p65 were blocked by BTE. BTE treatment blocked LPS-induced DNA-binding activity of NF-κB. BTE-fed, DSS-exposed mice showed the less weight loss, longer colon length and lower histologic score compared to control diet-fed, DSS-exposed mice. DSS-induced IκBα phosphorylation/degradation and phosphorylation of NF-κB/p65 were blocked by BTE. An increase of cleaved caspase-3 and poly (ADP-ribose) polymerase (PARP) in DSS-exposed mice was blocked by BTE. CONCLUSIONS: These results indicate that BTE attenuates colon inflammation through the blockage of NF-κB signaling and apoptosis in DSS-induced experimental colitis model.

Small interfering RNA-directed targeting of RON alters invasive and oncogenic phenotypes of human hepatocellular carcinoma cells.

The recepteur d'origine nantais (RON) receptor tyrosine kinase is highly expressed in various cancers including human hepatocellular carcinoma (HCC) and involved in tumor progression. The aims of the current study were to evaluate whether RON affects tumor cell behavior and oncogenic signaling cascades in HCC cells. We investigated the biologic role of RON on tumor cell behavior and oncogenic signaling cascades including Akt, c-Raf and extracellular signal-regulated kinase (ERK) by using the small interfering RNA (siRNA) in HCC cell lines, chang, HepG2 and Huh7. Knockdown of RON suppressed tumor cell migration and invasion in all tested HCC cell lines. The proportion of apoptotic cells induced by knockdown of RON was greater than that induced by transfection of the scramble siRNA in all tested HCC cell lines. Knockdown of RON resulted in cell cycle arrest in the G2/M phase of chang and Huh7 cells, and sub G1 phase of HepG2 cells. Knockdown of RON activated cleaved caspase-3 and PARP, and down-regulated the expression of Bcl-2, Bcl-xL and survivin, leading to induction of apoptosis in all tested cell lines. Knockdown of RON negatively regulates the progression of the cell cycle by decreasing cyclin D1 and D3, and increasing p21 and p27 in all tested cell lines. The phosphorylation of Akt, c-Raf and ERK1/2 signal proteins was significantly blocked by knockdown of RON in all tested cell lines. These results suggest that RON is associated with invasive and oncogenic phenotypes such as tumor cell migration, invasion, resistance to apoptosis and cell cycle arrest through the modulation of Akt, c-Raf and ERK signaling cascades in HCC cells.

LL-37 suppresses sodium nitroprusside-induced apoptosis of systemic sclerosis dermal fibroblasts.

The human cathelicidin antimicrobial peptide LL-37 regulates apoptosis of several cell types. Defective apoptosis of skin fibroblasts may contribute to systemic sclerosis (SSc). Here, we show that LL-37 inhibited apoptosis of SSc fibroblasts and identified the signalling pathways by which LL-37 mediates apoptosis. Immunohistochemistry showed that cathelicidin expression was enhanced in SSc patients compared with healthy controls. In addition, LL-37 decreased sodium nitroprusside (SNP)-induced apoptosis of SSc fibroblasts. LL-37 significantly increased expression of Bcl-2 and decreased levels of BAX protein. Pretreatment with LL-37 decreased activation of caspase-3 following SNP-treatment. Moreover, exposure of SSc fibroblasts to LL-37 resulted in increased expression of COX-2 and stimulation of prostaglandin E(2) (PGE(2)). Furthermore, LL-37 induced phosphorylation of ERK and the ERK inhibitor PD98059 blocked the inhibitory effect of LL-37 on apoptosis. Our data indicate that LL-37 may be associated with skin sclerosis by inhibiting apoptosis of dermal fibroblasts.

L-kynurenine-induced apoptosis in human NK cells is mediated by reactive oxygen species.

Recent studies have shown that indoleamine 2,3-dioxygenase (IDO) plays a pivotal role in the modulation of immune response against tumor and virus infection. Here we demonstrate the pro-apoptotic effect of L-kynurenine, a tryptophan catabolite of IDO, on human NK cell line, NK92 MI. Treatment with L-kynurenine dose-dependently induced growth inhibition and apoptosis in NK92 MI cells. Treatment with the antioxidant NAC completely protected cells from L-kynurenine-induced apoptosis. Moreover, we found that treatment with Z-VAD-fmk and ZB4 slightly inhibited L-kynurenine-induced apoptosis, suggesting that L-kynurenine-induced apoptosis in NK cells occurs primarily through an ROS mediated pathway. We observed that the presence of NAC blocks cytochrome c release and activation of caspase-3 during L-kynurenine-induced apoptosis. Overall, we conclude that L-kynurenine resulting from IDO can cause cell death via ROS pathway in NK cells. Our findings provide a new insight into the interaction between NK cells and IDO positive cancer cells in regulating immune responses.

Endoplasmic reticulum stress-mediated apoptosis of EBV-transformed B cells by cross-linking of CD70 is dependent upon generation of reactive oxygen species and activation of p38 MAPK and JNK pathway.

CD70 is expressed in normal activated immune cells as well as in several types of tumors. It has been established that anti-CD70 mAb induces complement-dependent death of CD70(+) tumor cells, but how anti-CD70 mAb affects the intrinsic signaling is poorly defined. In this report, we show that ligation of CD70 expressed on EBV-transformed B cells using anti-CD70 mAb induced production of reactive oxygen species (ROS) and subsequent apoptosis. We observed an early expression of endoplasmic reticulum (ER) stress response genes that preceded the release of apoptotic molecules from the mitochondria and the cleavage of caspases. CD70-induced apoptosis was inhibited by pretreatment with the ER stress inhibitor salubrinal, ROS quencher N-acetylcysteine, and Ca(2+) chelator BAPTA. We supposed that ROS generation might be the first event of CD70-induced apoptosis because N-acetylcysteine blocked increases of ROS and Ca(2+), but BAPTA did not block ROS generation. We also found that CD70 stimulation activated JNK and p38 MAPK. JNK inhibitor SP600125 and p38 inhibitor SB203580 effectively blocked upregulation of ER stress-related genes and cleavage of caspases. Inhibition of ROS generation completely blocked phosphorylation of JNK and p38 MAPK and induction of ER stress-related genes. Taken together, we concluded that cross-linking of CD70 on EBV-transformed B cells triggered ER stress-mediated apoptosis via ROS generation and JNK and p38 MAPK pathway activation. Our report reveals alternate mechanisms of direct apoptosis through CD70 signaling and provides data supporting CD70 as a viable target for an Ab-based therapy against EBV-related tumors.

Vitamin C attenuates ERK signalling to inhibit the regulation of collagen production by LL-37 in human dermal fibroblasts.

Vitamin C is used as an anti-ageing agent because of its collagen enhancing effects. The precise cellular signalling mechanism of vitamin C is not well known. Here, we investigate the profibrotic mechanism of vitamin C against LL-37. Antimicrobial peptide LL-37 decreases collagen expression at mRNA and protein levels in human dermal fibroblasts (HDFs). The ability of LL-37 to inhibit collagen expression is dependent on phosphorylation of extracellular signal-regulated kinase (ERK). HDFs and human keloid fibroblasts were treated with vitamin C followed by 2 h of LL-37 treatment. Collagen mRNA expression and total soluble collagen production inhibited by LL-37 was enhanced by treatment with 0.5 mm vitamin C. Vitamin C also decreased intracellular reactive oxygen intermediates (ROI) levels that were increased by LL-37. Furthermore, the phosphorylation of ERK was analysed by Western blot following treatment with vitamin C and LL-37. Vitamin C turned off phosphorylation of ERK that was induced by LL-37. Ets-1 transcriptional factor, which is involved in the regulation of collagen expression by LL-37, was also inhibited by vitamin C. This study shows that vitamin C enhances collagen production by inhibiting the ERK pathway induced by LL-37.