Expression of Epithelial-Mesenchymal Transition Markers in Epidermal Layer of Atopic Dermatitis.

The epithelial-mesenchymal transition (EMT) is a phenomenon, in which epithelial cells acquire a mesenchymal cell phenotype. It is important during wound healing; however, chronic inflammation leads to excessive EMT and causes tissue barrier dysfunction with hyperplasia. EMT is induced by several cytokines, such as interleukin (IL)-4 and IL-13. Additionally, IL-4 and IL-13 are known to increase in atopic dermatitis (AD) characterized by intense itching and eczema. Therefore, we assumed that there was commonality between the respective EMT and AD phenotypes. Herein, we evaluated EMT marker expression in AD skin and demonstrated that EMT-maker Snai1 and Twist expression were increased in AD mice model and patients with AD. Moreover, the epithelial-marker keratin 5 and mesenchymal marker Vimentin were co-expressed in the skin epidermis of mice with AD, suggesting the existence of hybrid epithelial-mesenchymal (E/M) cells possessing both epithelial and mesenchymal characteristics. In fact, we found that ΔNp63a, a stabilizing factor for hybrid E/M cells, was upregulated in the skin epidermis of the AD model mouse. Interestingly, increased expression of EMT markers was observed even at a nonlesion site in a patient with AD without initial inflammation or scratching. Therefore, EMT-like phenomena may occur independently of wound healing in skin of patients with AD.

Identification of a Novel Bone Marrow Cell-Derived Accelerator of Fibrotic Liver Regeneration Through Mobilization of Hepatic Progenitor Cells in Mice.

Granulocyte colony stimulating factor (G-CSF) has been reported to ameliorate impaired liver function in patients with advanced liver diseases through mobilization and proliferation of hepatic progenitor cells (HPCs). However, the underlying mechanisms remain unknown. We previously showed that G-CSF treatment increased the number of bone marrow (BM)-derived cells migrating to the fibrotic liver following repeated carbon tetrachloride (CCl4 ) injections into mice. In this study, we identified opioid growth factor receptor-like 1 (OGFRL1) as a novel BM cell-derived accelerator of fibrotic liver regeneration in response to G-CSF treatment. Endogenous Ogfrl1 was highly expressed in the hematopoietic organs such as the BM and spleen, whereas the liver contained a relatively small amount of Ogfrl1 mRNA. Among the peripheral blood cells, monocytes were the major sources of OGFRL1. Endogenous Ogfrl1 expression in both the peripheral blood monocytes and the liver was decreased following repeated CCl4 injections. An intrasplenic injection of cells overexpressing OGFRL1 into CCl4 -treated fibrotic mice increased the number of HPC and stimulated proliferation of hepatic parenchymal cells after partial resection of the fibrotic liver. Furthermore, overexpression of OGFRL1 in cultured HPC accelerated their differentiation as estimated by increased expression of liver-specific genes such as hepatocyte nuclear factor 4α, cytochrome P450, and fatty acid binding protein 1, although it did not affect the colony forming ability of HPC. These results indicate a critical role of OGFRL1 in the mobilization and differentiation of HPC in the fibrotic liver, and administration of OGFRL1-expressing cells may serve as a potential regenerative therapy for advanced liver fibrosis. Stem Cells 2019;37:89-101.

Expression of the clustered NeuAcα2-3Galß O-glycan determines the cell differentiation state of the cells.

Human embryonic stem cells (hESCs) are pluripotent stem cells from early embryos, and their self-renewal capacity depends on the sustained expression of hESC-specific molecules and the suppressed expression of differentiation-associated genes. To discover novel molecules expressed on hESCs, we generated a panel of monoclonal antibodies against undifferentiated hESCs and evaluated their ability to mark cancer cells, as well as hESCs. MAb7 recognized undifferentiated hESCs and showed a diffuse band with molecular mass of >239 kDa in the lysates of hESCs. Although some amniotic epithelial cells expressed MAb7 antigen, its expression was barely detected in normal human keratinocytes, fibroblasts, or endothelial cells. The expression of MAb7 antigen was observed only in pancreatic and gastric cancer cells, and its levels were elevated in metastatic and poorly differentiated cancer cell lines. Analyses of MAb7 antigen suggested that the clustered NeuAcα2-3Galß O-linked oligosaccharides on DMBT1 (deleted in malignant brain tumors 1) were critical for MAb7 binding in cancer cells. Although features of MAb7 epitope were similar with those of TRA-1-60, distribution of MAb7 antigen in cancer cells was different from that of TRA-1-60 antigen. Exposure of a histone deacetylase inhibitor to differentiated gastric cancer MKN74 cells evoked the expression of MAb7 antigen, whereas DMBT1 expression remained unchanged. Cell sorting followed by DNA microarray analyses identified the down-regulated genes responsible for the biosynthesis of MAb7 antigen in MKN74 cells. In addition, treatment of metastatic pancreatic cancer cells with MAb7 significantly abrogated the adhesion to endothelial cells. These results raised the possibility that MAb7 epitope is a novel marker for undifferentiated cells such as hESCs and cancer stem-like cells and plays a possible role in the undifferentiated cells.

Anti-fibrotic effects of a novel small compound on the regulation of cytokine production in a mouse model of colorectal fibrosis.

Intestinal fibrotic stricture is a major complication of inflammatory bowel disease. Despite its clinical importance, anti-fibrotic therapy has not been implemented. Transforming growth factor-ß (TGF-ß) is considered to be a major factor contributing to tissue fibrosis. We have previously shown that the administration of a small compound, HSc025, which promotes the nuclear translocation of YB-1 as a downstream effector of IFN-γ and antagonizes TGF-ß/Smad signaling, improves fibrosis in several murine tissues. In this study, we evaluated the anti-fibrotic effect of HSc025 on colorectal fibrosis in TNBS-induced murine chronic colitis. Daily oral administration of HSc025 (3, 15 and 75 mg/kg) suppressed collagen production and decreased the severity of colorectal fibrosis in a dose-dependent manner. In addition, the local production of TGF-ß was decreased after HSc025 treatment, whereas that of IL-13 and TNF-α was not affected. HSc025 administration maintained the level of IFN-γ production, even at a late stage when IFN-γ production was lost without the drug treatment. These results demonstrate that HSc025 could be a therapeutic candidate for intestinal fibrosis in inflammatory bowel disease that acts by altering the local production of cytokines, as well as by directly suppressing collagen production.

A novel small compound that promotes nuclear translocation of YB-1 ameliorates experimental hepatic fibrosis in mice.

Transforming growth factor-ß (TGF-ß) is considered to be a major factor contributing to liver fibrosis. We have previously shown that nuclear translocation of YB-1 antagonizes the TGF-ß/Smad3 signaling in regulating collagen gene expression. More recently, we have demonstrated that the novel small compound HSc025 promotes nuclear translocation of YB-1, resulting in the improvement of skin and pulmonary fibrosis. Here, we presented evidence as to the mechanism by which HSc025 stimulates nuclear translocation of YB-1 and the pharmacological effects of HSc025 on a murine model of hepatic fibrosis. A proteomics approach and binding assays using HSc025-immobilized resin showed that HSc025 binds to the amino acid sequence within the C-tail region of YB-1. In addition, immunoprecipitation experiments and glutathione S-transferase pulldown assays identified poly(A)-binding protein (PABP) as one of the cytoplasmic anchor proteins of YB-1. HSc025 directly binds to YB-1 and interrupts its interaction with PABP, resulting in accelerated nuclear translocation of YB-1. Transfection of cells with PABP siRNA promoted nuclear translocation of YB-1 and subsequently inhibited basal and TGF-ß-stimulated collagen gene expression. Moreover, HSc025 significantly suppressed collagen gene expression in cultured activated hepatic stellate cells. Oral administration of HSc025 to mice with carbon tetrachloride-induced hepatic fibrosis improved liver injury as well as the degree of hepatic fibrosis. Altogether, the results provide a novel insight into therapy for organ fibrosis using YB-1 modulators.

Novel anti-fibrotic modalities for liver fibrosis: molecular targeting and regenerative medicine in fibrosis therapy.

Based on the cellular and molecular mechanisms underlying hepatic fibrogenesis, several kinds of approaches have been proposed to treat liver fibrosis. Among a number of growth factors and cytokines that regulate collagen metabolism, transforming growth factor (TGF)-ß is the most potent factor to accelerate liver fibrosis by activating hepatic stellate cells, stimulating collagen gene transcription, and suppressing matrix metalloproteinases expression. Thus, TGF-ß as well as its intracellular mediators, Smad proteins, can be potential therapeutic targets for liver fibrosis. Constitutive phosphorylation and nuclear accumulation of Smad3 is the common feature of activated stellate cells. We have synthesized a novel small compound that inhibits Smad3-dependent collagen gene transcription by promoting nuclear import of a transcriptional repressor, YB-1. Another insight into anti-fibrotic strategies is the contribution of bone marrow-derived cells to the regression of liver fibrosis. Administration of granulocyte-colony stimulating factor enhanced the migration of bone marrow-derived cells into fibrotic liver tissue and accelerated the regression of experimental liver fibrosis. We have recently identified novel unknown factors expressed by bone marrow-derived cells that not only ameliorate liver fibrosis but also accelerate regeneration of fibrotic liver.

A novel adipokine GM2AP impairs insulin signaling.

In an attempt to discover novel adipokines, we performed proteomics analyses using culture medium from differentiated 3T3-L1 adipocytes, and first identified GM2AP. The levels of GM2AP mRNA and protein were augmented by adipogenesis in cultured adipocytes and expression in adipose tissue and serum of obese mice or human subjects was found to be significantly higher than in lean counterparts. Exposure of 3T3-L1 adipocytes to GM2AP protein accelerated dissociation of insulin receptor-beta (IRß) from caveolin-1, and interrupted insulin signal transduction. Abrogation of GM2AP function by specific antibodies augmented glucose uptake. Furthermore, treatment of rat pheochromocytoma PC12 NS1 cells with GM2AP impaired NGF signal transduction. Taken together, these results provide novel insights into the physiological functions of GM2AP in obesity.

Circulating natural antibodies against 3'-sialyllactose complement the diagnostic performance of CA19-9 for the early detection of pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma is a devastating malignancy with an extremely poor prognosis. Although the most widely used biomarker for pancreatic cancer is carbohydrate antigen CA19-9, it is elevated mainly in the late stage of pancreatic cancer. Some serum natural antibodies against carbohydrates have been shown to be possible diagnostic markers for cancer. OBJECTIVE: This study was conducted to determine whether the level of natural antibodies against carbohydrates fluctuates in pancreatic ductal adenocarcinoma. METHODS: Serum from pancreatic cancer subjects (n= 55) and 43 subjects free of malignant disease were studied. The contents of natural antibodies against sialyl glycans and CA19-9 in serum were determined by enzyme-linked immunosorbent assay. RESULTS: The level of serum anti-3'-sialyllactose antibodies in pancreatic cancer subjects was significantly lower than that in healthy controls. In contrast, the amounts of serum antibodies against other sialyl glycans were comparable between the two groups. Concentration of serum anti-3'-sialyllactose IgG provided excellent AUC of 0.86, with sensitivity 82%, specificity 81%, and accuracy 82%. The combination of serum anti-3'-sialyllactose IgG with CA19-9 improved the sensitivity of pancreatic cancer detection at an early stage. CONCLUSIONS: Natural antibodies against 3'-sialyllactose constitute a promising biomarker for pancreatic cancer detection. The measurement of serum anti-3'-sialyllactose antibodies could play a supportive role in diagnostics and complement the performance of CA19-9 for the early detection of pancreatic ductal adenocarcinoma.

Homeostatic Function of Dermokine in the Skin Barrier and Inflammation.

Dermokine is a chiefly skin-specific secreted glycoprotein localized in the upper epidermis, and its family consists of three splice variants in mice and five in humans. To investigate the pathophysiological impact of dermokine, we generated mice deficient for two (ßγ) or all dermokine isoforms (αßγ). Both variants, especially dermokine αßγ-deficient mice exhibited scale and wrinkle formation resembling ichthyosis accompanied by transepidermal water imbalance at the neonatal stage. Several dermokine αßγ-deficient mice died by postnatal day 21 when reared under low humidity. Moreover, the cornified envelope was vulnerable, and skin barrier lipid ceramides were reduced in the epidermis of dermokine αßγ-deficient mice. cDNA microarray and quantitative reverse transcriptase-PCR assays of the epidermis revealed the upregulation of small proline-rich protein and late cornified envelope family members, as well as antimicrobial peptides in the dermokine αßγ-deficient mice. These barrier gene signatures were similar to that seen in psoriasis, whereas recent studies demonstrated that congenital ichthyosis has gene profiles resembling psoriasis. In line with these findings, adult dermokine αßγ-deficient mice exhibited aggravated phenotypes in psoriasis-like dermatitis models but not in allergic dermatitis models. Dermokine may play a regulatory role in inflammatory dyskeratotic diseases, such as congenital ichthyosis and psoriasis, in the crosstalk between barrier dysfunction and inflammation.

Hepatocyte growth factor suppresses profibrogenic signal transduction via nuclear export of Smad3 with galectin-7.

BACKGROUND & AIMS: Hepatocyte growth factor (HGF) and transforming growth factor-beta (TGF-beta) regulate diversified cellular functions and often act antagonistically against each other. For example, TGF-beta is the most potent factor accelerating liver fibrosis, whereas HGF treatment prevents its progression. Here, we propose a novel molecular mechanism by which HGF counter represses TGF-beta-stimulated profibrogenic signal transduction. METHODS: Effects of HGF on TGF-beta-responsive gene transcription of type I collagen, the major matrix component of fibrotic liver, were examined by using cultured hepatic stellate cells (HSC) and transgenic mice harboring alpha2(I) collagen gene (COL1A2) promoter. Expression and subcellular localization of Smad3 were determined by Western blot analyses and immunofluorescence staining, respectively. A mass spectrometric analysis was employed to identify immunoprecipitated proteins with antiphospho-Smad2/3 antibodies. RESULTS: Over expression of HGF inhibited COL1A2 transcription in cultured HSC and suppressed activation of COL1A2 promoter in liver tissue induced by carbon tetrachloride administration. A mass spectrometric analysis identified galectin-7 as one of the immunoprecipitated proteins with antiphospho-Smad2/3 antibodies following HGF treatment. HGF accelerated nuclear export of Smad3 by enhancing its interaction with galectin-7. Transfection of cells with galectin-7 small interfering RNA inhibited nuclear export of Smad3 and abolished suppressive effect of HGF on expression of TGF-beta-responsive genes such as COL1A2 and plasminogen activator inhibitor-1. On the other hand, over expression of galectin-7 suppressed TGF-beta-stimulated expression of those target genes. CONCLUSIONS: These results reveal a novel function of intracellular galectin-7 as a transcriptional regulator via its interaction with Smad3 and provide a molecular basis for the antifibrotic effect of HGF.

Application of Monoclonal Antibodies Against Mouse Dermokine.

Dermokine is one of the most highly expressed proteins in differentiating keratinocytes. Mouse dermokine has been reported to be encoded by 22 exons, and its expression leads to three transcripts, ß, γ, and α, which are transcribed from two different transcriptional start sites. The α isoform represents the carboxyl-terminal domain of the ß isoform, whereas the γ isoform lacks this domain. To reveal the distributions and expression levels of each isoform in mice, we generated rat monoclonal antibodies against dermokine-ß/γ and dermokine-ß/α. In immunofluorescence studies, the expression levels of dermokine in the cytosol of the cultured mouse keratinocytes were significantly elevated by high levels of extracellular calcium. In Western blot analyses, the expression levels of dermokine-ß and dermokine-α were increased in the presence of high calcium. Finally, we developed a monoclonal antibody-based sensitive sandwich enzyme-linked immunosorbent assay (ELISA) and showed that the secreted dermokine-ß into the culture medium from mouse keratinocytes was significantly increased in a manner dependent on the extracellular calcium concentration. These dermokine-specific antibodies have allowed us to gain new insights into the role of each dermokine isoform in cutaneous homeostasis.

Editor's Highlight: Development of Novel Neural Embryonic Stem CellTests for High-Throughput Screening of Embryotoxic Chemicals.

There is a great demand for appropriate alternative methods to rapidly evaluate the developmental and reproductive toxicity of a wide variety of chemicals. We used the differentiation of mouse embryonic stem cells (mESCs) into cardiomyocytes as a basis for establishing a rapid and highly reproducible invitro embryotoxicity test known as the Hand1-Luc Embryonic Stem Cell Test (Hand1-Luc EST). In this study, we developed novel neural-Luc ESTs using two marker genes for neural development, tubulin beta-3 (Tubb3) and Reelin (Reln), and evaluated the capacity of these tests to predict developmental toxicity. In addition, we tested whether an integrated approach (a combination of neural-Luc ESTs and the Hand1-Luc EST) improved developmental toxicant detection. To perform our neural-Luc ESTs, we needed to generate stable transgenic mESCs with individual promoters linked to the luciferase gene, and to establish that similar changes in promoter activities and mRNA expression levels occur during neural differentiation. Based on the concentration-response curves of 15 developmental toxicants and 17 non-developmental toxic chemicals, we derived a prediction formula and assessed the capacity of this formula to predict developmental toxicity. Although both were highly sensitive and specific for predicting developmental toxicity, neural-Luc ESTs had similar predictive capacities. In contrast, neural-Luc ESTs and Hand1-Luc EST had significantly different predictive powers. As expected, the combination of these ESTs increased the sensitivity of developmental toxicant detection. These results demonstrate the convenience and the usefulness of this combination of ESTs as an alternative assay system for future toxicological and mechanistic studies of developmental toxicity.

Novel phototoxicity assay using human embryonic stem cell-derived retinal pigment epithelial cells.

Some chemicals are harmful in to light-exposed tissues such as skin and eyes. The 3T3 Neutral Red Uptake Phototoxicity Test has been validated and adopted by the Organization of Economic and Community Development (OECD) as a method of evaluating chemical phototoxicity using mouse 3T3 fibroblasts. However, the high rate of false positive results associated with this test eventually led to increased laboratory animal usage. Although the eye is vulnerable to light damage because of constant exposure to environmental radiation, few approaches are available to predict ocular phototoxicity in humans. Here, we propose a tier one test that identifies the potential ocular phototoxicity of chemical substances. Using a three-dimensional culture technique, human embryonic stem cells (hESCs) were differentiated to retinal pigment epithelial cell (RPE) precursors. The precursors after prolonged treatment with FBS formed a uniform hexagonal lattice of cells with well-developed tight junctions and time-dependent elevation of melanin content and RPE maturation marker levels. Hierarchical clustering of gene transcripts revealed that hESC-derived RPEs were very similar to tissue-derived adult RPEs. Interestingly, there were a high percentage of chemicals eliciting a positive response in 3T3 cells and negative in hESC-derived RPEs under the experimental conditions used in the phototoxicity test. The response to treatment of hESC-derived RPEs with these negative chemicals became positive at a higher dose of UVA irradiation; however, the biological responses to these chemicals differed between the two cells. Taken together, we conclude that hESC-derived RPEs are novel tool for future toxicological and mechanistic studies of ocular phototoxicity in humans.

Generation of Rat Monoclonal Antibodies Against Human Pancreatic Ductal Adenocarcinoma Cells.

Pancreatic ductal adenocarcinoma is an aggressive tumor with a poor prognosis. Biomarkers that can detect the tumor in its early stages when it may be amenable to curative resection might improve prognosis. To discover novel markers expressed in primary pancreatic cancer, we generated a panel of monoclonal antibodies against pancreatic ductal adenocarcinoma cell line BxPC3 using a rat medial iliac lymph node method. The antigen recognized by 1B5A5 was expressed on the cell surface and secreted into the conditioned medium of BxPC3 cells, and characterized as glycoproteins with molecular mass between 60 and 90 kDa. A wide range of molecular weights of 1B5A5 antigen in several pancreatic cancer cell lines were observed. Immunohistochemistry using a human multiple organ tumor tissue array showed an enhanced expression of 1B5A5 antigen in pancreas, lung, stomach, breast, urinary bladder, colon, and cervix uteri cancers. Immunoprecipitation followed by proteomic analyses identified CEACAM6 as a 1B5A5 antigen. In addition, western blot analysis results indicated that the 1B5A5 epitope is located within an amino-terminal domain of CEACAM6. These results raised the possibility that our approach could lead to discovery of novel biomarkers for the early stage of cancers in a relatively short period of time.

A novel marker for undifferentiated human embryonic stem cells.

Human embryonic stem cells (hESCs) are pluripotent stem cells from early embryos, and their self-renewal capacity depends on the sustained expression of hESC-specific molecules and the suppressed expression of differentiation-associated genes. To discover novel molecules expressed on hESCs, we generated a panel of monoclonal antibodies against undifferentiated hESCs. The antigen recognized by MAb2 is expressed on the cell surface of undifferentiated hESCs; three diffused bands with molecular mass between 30 and 60 kDa in the lysates of hESCs were diminished during hESC differentiation into neural cells. The expression of MAb2 antigen was also observed on the plasma membrane of lung cancer cells, and MAb2 detected 55, 50, and 35 kDa protein bands in the cell lysates. Immunoprecipitation followed by proteomics analyses identified CD147/basigin as a MAb2 antigen. Finally, the positive expression of CD147/basigin protein in undifferentiated hESCs was confirmed. These results suggested that CD147/basigin could be another undifferentiated hESC marker.

A novel small compound accelerates dermal wound healing by modifying infiltration, proliferation and migration of distinct cellular components in mice.

BACKGROUND: Impaired wound healing in skin ulcer is one of the major medical issues in the aged society. Wound healing is a complex process orchestrated by a number of humoral factors and cellular components. TGF-ß is known to stimulate collagen production in dermal fibroblasts while inhibiting proliferation of epidermal keratinocyte. A screening of small compounds that suppress type I collagen production in fibroblasts has identified HSc025 that antagonizes the TGF-ß/Smad signal. OBJECTIVE: We examined the effects of HSc025 on dermal wound healing and elucidated the underlying mechanisms. METHODS: Effects of HSc025 on the wound closure process were evaluated in a murine full-thickness excisional wound healing model. Cell proliferation and migration were estimated using primary cultures of human keratinocytes and fibroblasts. Comprehensive analyses of gene expression profiles were performed using untreated and HSc025-treated fibroblasts. RESULTS: Oral HSc025 administration suppressed macrophage infiltration and accelerated wound closure as early as at day 2 after the dermal excision. Treatment of cultured keratinocytes with HSc025 counteracted the inhibitory effects of TGF-ß on cell proliferation and migration. On the other hand, HSc025 stimulated migration, but not proliferation, of dermal fibroblasts independently of TGF-ß. Experiments using an artificial dermis graft revealed that HSc025 stimulated migration of collagen-producing cells into the graft tissue. A cDNA microarray analysis of untreated and HSc025-treated fibroblasts identified pirin as a critical mediator accelerating fibroblast migration. CONCLUSION: HSc025 accelerates wound healing by modifying infiltration, proliferation and migration of distinct cellular components, which provides a novel insight into the therapy for intractable skin ulcer.

Dermokine inhibits ELR(+)CXC chemokine expression and delays early skin wound healing.

BACKGROUND: Dermokine-ß is abundant in stratified epithelia and in differentiating keratinocytes in culture. We have recently shown that treatment of keratinocytes with dermokine-ß attenuates phosphorylation of extracellular signal-regulated kinase, however, the roles of dermokine-ß in vivo remain unknown. OBJECTIVE: Dermokine-ß is overexpressed in marginal keratinocytes during wound healing. This study was conducted to investigate the roles of dermokine-ß in the wound healing process. METHODS: Recombinant human dermokine-ß or its active peptide was topically applied to excisional wounds in mice and the relative wound area was calculated. Histological and chemokine expression analyses in wounds were also performed. The chemokine expression levels as well as the chemotactic activity of dermokine-ß in cultured keratinocytes were determined. RESULTS: Topical application of recombinant dermokine-ß as well as its carboxy-terminal domain peptide inhibited mouse wound healing at an early phase, reduced infiltration of neutrophils and macrophages into the wounds, inhibited angiogenesis, and decreased the number of myofibroblasts in the wounds. Treatment with dermokine-ß augmented IL-10 expression, but attenuated expression of transforming growth factor-ß and tumor necrosis factor-α. In addition, application of dermokine-ß to skin wounds reduced the expression of CXCL1 and CXCL5, both of which are chemoattractant for neutrophils into wounds. Both dermokine-ß and its active peptide decreased the expression of CXCL1, CXCL6, and CXCL8 in cultured human keratinocytes. Treatment of human keratinocytes with dermokine-ß inhibited neutrophil chemotaxis. CONCLUSION: These results suggest that dermokine-ß delays early cutaneous wound healing in part by inhibiting expression of CXC chemokines containing the ERL-sequence motif.

Dermokine-ß impairs ERK signaling through direct binding to GRP78.

Dermokine-ß is abundant in stratified epithelia and in differentiating cultured keratinocytes. In this study, we investigated the role of dermokine-ß in differentiation of keratinocytes. Treatment of keratinocytes or skin tumor cells with dermokine-ß attenuated phosphorylation of extracellular-signal-regulated kinase (ERK). Exposure of cells to dermokine-ß, as well as its carboxyl-terminus domain peptide, interrupted phosphorylation of ERK and stimulated dermokine gene expression. Inhibition of ERK signaling by its specific inhibitor also increased dermokine expression level. A combination of chemical cross-linking and immunoprecipitation, followed by proteomics analyses, identified glucose-regulated protein 78 (GRP78) as a dermokine-ß-associated protein. Blockage of GRP78 expression by a specific siRNA abrogated actions of dermokine-ß. These findings provide novel insights into the physiological significance of dermokine-ß in the epidermis.

Adipokine ganglioside GM2 activator protein stimulates insulin secretion.

Recently, we identified ganglioside GM2 activator protein (GM2AP) as a novel adipokine, and revealed that treatment of cultured cells with GM2AP impairs insulin signal transduction. The aim of this study was to examine the impact of GM2AP on glucose metabolism in vivo. Injection of recombinant GM2AP in mice significantly lowered blood glucose levels in glucose tolerance tests. Administration of GM2AP to mice for 10 days increased serum insulin levels, whereas the contents of glucose, leptin and FFA were significantly decreased. Stimulation of calcium influx and insulin secretion by GM2AP was observed in hamster insulinoma HIT-T15 cells. Blockage of GM2AP function by specific antibodies inhibited GM2AP-induced insulin secretion. These results provide novel insights into the physiological functions of GM2AP in obesity.

A novel inhibitor of Smad-dependent transcriptional activation suppresses tissue fibrosis in mouse models of systemic sclerosis.

OBJECTIVE: Tissue fibrosis is a major cause of morbidity and mortality in systemic sclerosis (SSc), and an increasing number of promising molecular targets for antifibrotic therapies have been described recently. Transforming growth factor beta (TGFbeta) is well known to be the principal factor that leads to tissue fibrosis. The present study was undertaken to investigate the ability of HSc025, a novel small compound that antagonizes TGFbeta/Smad signaling through the activation of nuclear translocation of Y-box binding protein 1, to prevent tissue fibrosis in vitro or in mouse models of SSc. METHODS: Human dermal fibroblasts were exposed to HSc025 at various concentrations in the presence of TGFbeta, and levels of collagen or fibronectin expression were determined. HSc025 (15 mg/kg/day for 14 days) was administered orally to tight skin mice and to mice with bleomycin-induced pulmonary fibrosis. Improvement of tissue fibrosis was evaluated by histologic or biochemical examination in each model. RESULTS: Pretreatment with HSc025 prevented Smad-dependent promoter activation, in a dose-dependent manner; however, HSc025 had no effect on TGFbeta-induced phosphorylation of Smad3. The inhibitory effects of HSc025 on TGFbeta-induced collagen or fibronectin expression were also confirmed in vitro. Orally administered HSc025 significantly reduced hypodermal thickness and hydroxyproline content in tight skin mice, and markedly decreased the histologic score and hydroxyproline content in the lungs of bleomycin-treated mice. CONCLUSION: These results demonstrate that HSc025 is a novel inhibitor of TGFbeta/Smad signaling, resulting in the improvement of skin and pulmonary fibrosis. Orally available HSc025 might therefore be useful in the treatment of SSc.