Yukie Yamaguchi

A Peptide Derived from Endostatin Ameliorates Organ Fibrosis

A naturally occurring peptide from endostatin can inhibit fibrosis in lung and skin, even when it is already established. Putting an End to Fibrotic Organ Failure with Endostatin? Organ fibrosis or “scarring” has the dubious distinction of accounting for nearly half of all deaths in the developed world, taking its toll in disorders ranging from liver cirrhosis to cardiovascular disease. There are no effective treatments for fibrosis, an out-of-control wound-healing process in which excess extracellular matrix components such as collagen and fibronectin replace normal tissue, ultimately resulting in organ failure. Endostatin, a naturally occurring proteolytic fragment of one form of collagen, is elevated in patients with different forms of fibrosis. Previously, endostatin was shown to inhibit the growth of new blood vessels, an effect attributed to its N-terminal region. Because signaling molecules involved in blood vessel formation are also present in fibrotic tissues, Yamaguchi et al. investigated whether endostatin might inhibit fibrosis as well. Indeed, they found that a recombinant form did inhibit dermal fibrosis, in this case induced by the profibrotic factor transforming growth factor–β (TGF-β) in an ex vivo human skin model. So, too, could a smaller peptide, termed E4, which was derived from the C terminus of endostatin. In addition, E4 prevented TGF-β–induced dermal fibrosis in a mouse model—as well as dermal and lung fibrosis induced by a different trigger, bleomycin. E4 also reduced bleomycin-induced cell death in the mouse lung. Furthermore, Yamaguchi et al. found that E4 could reverse ongoing fibrosis, in addition to preventing its initiation, in these models. Finally, the researchers showed that E4 reduced the expression of two key proteins: lysyl oxidase, an enzyme that cross-links collagen and thereby contributes to fibrosis, and the transcription factor Egr-1, which is a central fibrosis regulator. Because E4 can inhibit both skin and lung fibrosis, it may well be able to inhibit fibrosis in other tissues as well. Further research is needed to explore the therapeutic potential of this peptide for preventing or reversing organ fibrosis. Fibroproliferative disorders such as idiopathic pulmonary fibrosis and systemic sclerosis have no effective therapies and result in significant morbidity and mortality due to progressive organ fibrosis. We examined the effect of peptides derived from endostatin on existing fibrosis and fibrosis triggered by two potent mediators, transforming growth factor–β (TGF-β) and bleomycin, in human and mouse tissues in vitro, ex vivo, and in vivo. We identified one peptide, E4, with potent antifibrotic activity. E4 prevented TGF-β–induced dermal fibrosis in vivo in a mouse model, ex vivo in human skin, and in bleomycin-induced dermal and pulmonary fibrosis in vivo, demonstrating that E4 exerts potent antifibrotic effects. In addition, E4 significantly reduced existing fibrosis in these preclinical models. E4 amelioration of fibrosis was accompanied by reduced cell apoptosis and lower levels of lysyl oxidase, an enzyme that cross-links collagen, and Egr-1 (early growth response gene–1), a transcription factor that mediates the effects of several fibrotic triggers. Our findings identify E4 as a peptide with potent antifibrotic activity and a possible therapeutic agent for organ fibrosis.

Serum periostin levels are correlated with progressive skin sclerosis in patients with systemic sclerosis

Background  Periostin, a matricellular protein, serves as a regulator of wound healing and fibrosis. The role of periostin in the pathogenesis of systemic sclerosis (SSc) is unknown.

Periostin levels correlate with disease severity and chronicity in patients with atopic dermatitis

Recent findings indicate that periostin, an extracellular matrix protein induced by T helper 2 cytokines, plays a critical role in the pathogenesis of atopic dermatitis (AD).

Analysis of dermatomyositis-specific autoantibodies and clinical characteristics in Japanese patients

Dermatomyositis (DM) is an idiopathic systemic inflammatory disease that is often accompanied by interstitial lung disease (ILD) or internal malignancy. New autoantibodies, anti‐clinically amyopathic dermatomyositis 140 (anti‐CADM‐140) antibody (Ab) and anti‐155/140 Ab, as well as anti‐aminoacyl‐tRNA synthetase (anti‐ARS) Ab and anti‐Mi‐2 Ab, have been discovered and their utility indicated. However, the association between these autoantibodies and the clinical characteristics of DM is not fully understood, and it is unclear whether anti‐155/140 Ab is “specific” to DM patients with internal malignancy. Therefore, we analyzed 55 DM patients and 18 non‐DM patients with malignancy to evaluate the clinical characteristics, especially skin manifestations, in association with DM‐specific autoantibodies detected by immunoprecipitation. Six patients (11%) had anti‐CADM‐140 Ab, nine (16%) had anti‐155/140 Ab, eight (15%) had anti‐ARS Ab and six (11%) had anti‐Mi‐2 Ab. The frequency of DM patients positive for any type of autoantibody was 53%. Among the 20 DM patients with ILD, three (15%) had both anti‐CADM‐140 Ab and rapidly progressive ILD, and required intensive therapy (P < 0.05). ILD found in anti‐ARS Ab‐positive patients did not progress rapidly. The prevalence of muscle involvement in patients with anti‐CADM‐140 Ab was 83%. Among the 18 DM patients with internal malignancy, four (22%) had anti‐155/140 Ab, and internal malignancy was found in four cases (44%) of nine anti‐155/140 Ab‐positive patients. None of the non‐DM patients with malignancy were positive for anti‐155/140 Ab. In conclusion, the results of the present study indicate that anti‐155/140 Ab is specific to DM patients with internal malignancy and that we may be able to predict prognosis of ILD and the presence of malignancy to some extent, suggesting that examination of autoantibodies in DM patients is clinically very useful. However, further investigation is needed because several findings differ from those of previous reports.

Oral administration of collagen tripeptide improves dryness and pruritus in the acetone-induced dry skin model

BACKGROUND Dry skin causes pruritus and discomfort in patients with xerosis and atopic dermatitis. General treatment for skin dryness involves the topical application of an emollient. However, more effective, simpler therapies are desired. Collagen tripeptide (CTP) is a highly purified, non-antigenic, low-allergenic collagen fraction that is known to have various biological effects. OBJECTIVE To clarify the therapeutic effects of CTP for dry skin using acetone-induced dry skin model mice. METHODS ICR mice were treated with acetone followed by oral administration of CTP (80 or 500mg/kg/day) for 3 days. Hyaluronic acid production induced by CTP was assessed using human dermal fibroblasts in vitro and in an acetone-induced dry skin model mice in vivo. Transepidermal water loss (TEWL) and scratching behavior were evaluated. Furthermore, the effects of CTP on intraepidermal nerve fibers and expression of semaphorin 3A (Sema3A) and nerve growth factor (NGF) were examined by immunohistochemistry and quantitative RT-PCR. RESULTS CTP enhanced hyaluronic acid production in human dermal fibroblasts in vitro and in murine skin in vivo. Oral administration of CTP in acetone-induced dry skin model mice significantly decreased TEWL and suppressed scratching behavior. Intraepidermal nerve growth was dramatically inhibited in CTP-treated mice. Quantitative PCR analysis and immunohistochemical study revealed that CTP abolished the increased NGF and decreased Sema3A levels induced by acetone treatment. CONCLUSION Oral administration of CTP improves dry skin and normalizes axon-guidance factors in the epidermis in addition to reducing pruritus. CTP may be used in a new therapeutic strategy against dry skin and pruritus.

Human Skin Culture as an Ex Vivo Model for Assessing the Fibrotic Effects of Insulin-Like Growth Factor Binding Proteins

Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology. A hallmark of SSc is fibrosis of the skin and internal organs. We recently demonstrated increased expression of IGFBP-3 and IGFBP-5 in primary cultures of fibroblasts from the skin of patients with SSc. In vitro, IGFBP-3 and IGFBP-5 induced a fibrotic phenotype and IGFBP-5 triggered dermal fibrosis in mice. To assess the ability of IGFBPs to trigger fibrosis, we used an ex vivo human skin organ culture model. Our findings demonstrate that IGFBP-3 and IGFBP-5, but not IGFBP-4, increase dermal and collagen bundle thickness in human skin explants, resulting in substantial dermal fibrosis and thickening. These fibrotic effects were sustained for at least two weeks. Our findings demonstrate that human skin ex vivo is an appropriate model to assess the effects of fibrosis-inducing factors such as IGFBPs, and for evaluating the efficacy of inhibitors/therapies to halt the progression of fibrosis and potentially reverse it.

Periostin in Skin Tissue and Skin-Related Diseases

Extracellular matrix (ECM) is not only involved in the maintenance of normal physiological tissue but also in interactions with other ECM components, tissue remodeling, and modulating immune responses. The skin provides a distinctive environment characterized by rich fibroblasts producing various ECM proteins, epithelial-mesenchymal interactions, and immune responses induced by external stimuli. Recently, periostin-a matricellular protein-has been highlighted for its pivotal functions in the skin. Analysis of periostin null mice has revealed that periostin contributes to collagen fibrillogenesis, collagen cross-linking, and the formation of ECM meshwork via interactions with other ECM components. Periostin expression is enhanced by mechanical stress or skin injury; this is indicative of the physiologically protective functions of periostin, which promotes wound repair by acting on keratinocytes and fibroblasts. Along with its physiological functions, periostin plays pathogenic roles in skin fibrosis and chronic allergic inflammation. In systemic sclerosis (SSc) patients, periostin levels reflect the severity of skin fibrosis. Periostin null mice have shown reduced skin fibrosis in a bleomycin-induced SSc mouse model, indicating a key role of periostin in fibrosis. Moreover, in atopic dermatitis (AD), attenuated AD phenotype has been observed in periostin null mice in a house dust mite extract-induced AD mouse model. Th2 cytokine-induced periostin acts on keratinocytes to produce inflammatory cytokines that further enhance the Th2 response, thereby sustaining and amplifying chronic allergic inflammation. Thus, periostin is deeply involved in the pathogenesis of AD and other inflammation-related disorders affecting the skin. Understanding the dynamic actions of periostin would be key to dissecting pathogenesis of skin-related diseases and to developing novel therapeutic strategies.Extracellular matrix (ECM) is not only involved in the maintenance of normal physiological tissue but also in interactions with other ECM components, tissue remodeling, and modulating immune responses. The skin provides a distinctive environment characterized by rich fibroblasts producing various ECM proteins, epithelial-mesenchymal interactions, and immune responses induced by external stimuli. Recently, periostin-a matricellular protein-has been highlighted for its pivotal functions in the skin. Analysis of periostin null mice has revealed that periostin contributes to collagen fibrillogenesis, collagen cross-linking, and the formation of ECM meshwork via interactions with other ECM components. Periostin expression is enhanced by mechanical stress or skin injury; this is indicative of the physiologically protective functions of periostin, which promotes wound repair by acting on keratinocytes and fibroblasts. Along with its physiological functions, periostin plays pathogenic roles in skin fibrosis and chronic allergic inflammation. In systemic sclerosis (SSc) patients, periostin levels reflect the severity of skin fibrosis. Periostin null mice have shown reduced skin fibrosis in a bleomycin-induced SSc mouse model, indicating a key role of periostin in fibrosis. Moreover, in atopic dermatitis (AD), attenuated AD phenotype has been observed in periostin null mice in a house dust mite extract-induced AD mouse model. Th2 cytokine-induced periostin acts on keratinocytes to produce inflammatory cytokines that further enhance the Th2 response, thereby sustaining and amplifying chronic allergic inflammation. Thus, periostin is deeply involved in the pathogenesis of AD and other inflammation-related disorders affecting the skin. Understanding the dynamic actions of periostin would be key to dissecting pathogenesis of skin-related diseases and to developing novel therapeutic strategies.

Interleukin-18 is elevated in the horny layer in patients with atopic dermatitis and is associated with Staphylococcus aureus colonization

Background  An increase in interleukin (IL)‐18 production from epidermal cells has been reported in an atopic dermatitis (AD) mouse model, and subsequent topical application of Staphylococcus aureus results in severe dermatitis.

A randomized double-blind trial of intravenous immunoglobulin for bullous pemphigoid.

BACKGROUND Patients with steroid-resistant bullous pemphigoid (BP) require an appropriate treatment option. OBJECTIVE A multicenter, randomized, placebo-controlled, double-blind trial was conducted to investigate the therapeutic effect of high-dose intravenous immunoglobulin (IVIG; 400mg/kg/day for 5days) in BP patients who showed no symptomatic improvement with prednisolone (≥0.4mg/kg/day) administered. METHODS We evaluated the efficacy using the disease activity score on day15 (DAS15) as a primary endpoint, and changes in the DAS over time, the anti-BP180 antibody titer, and safety for a period of 57days as secondary endpoints. RESULTS We enrolled 56 patients in this study. The DAS15 was 12.5 points lower in the IVIG group than in the placebo group (p=0.089). The mean DAS of the IVIG group was constantly lower than that of the placebo group throughout the course of observation, and a post hoc analysis of covariance revealed a significant difference (p=0.041). Furthermore, when analyzed only in severe cases (DAS≥40), the DAS15 differed significantly (p=0.046). The anti-BP180 antibody titers showed no difference between the two groups. CONCLUSION IVIG provides a beneficial therapeutic outcome for patients with BP who are resistant to steroid therapy.

Enhanced angiogenic potency of monocytic endothelial progenitor cells in patients with systemic sclerosis

IntroductionMicrovasculopathy is one of the characteristic features in patients with systemic sclerosis (SSc), but underlying mechanisms still remain uncertain. In this study, we evaluated the potential involvement of monocytic endothelial progenitor cells (EPCs) in pathogenic processes of SSc vasculopathy, by determining their number and contribution to blood vessel formation through angiogenesis and vasculogenesis.MethodsMonocytic EPCs were enriched and enumerated using a culture of peripheral blood mononuclear cells and platelets on fibronectin in 23 patients with SSc, 22 patients with rheumatoid arthritis (RA), and 21 healthy controls. To assess the capacity of monocytic EPCs to promote vascular formation and the contribution of vasculogenesis to this process, we used an in vitro co-culture system with human umbilical vein endothelial cells (HUVECs) on Matrigel® and an in vivo murine tumor neovascularization model.ResultsMonocytic EPCs were significantly increased in SSc patients than in RA patients or healthy controls (P = 0.01 for both comparisons). Monocytic EPCs derived from SSc patients promoted tubular formation in Matrigel® cultures more than those from healthy controls (P = 0.007). Transplantation of monocytic EPCs into immunodeficient mice resulted in promotion of tumor growth and blood vessel formation, and these properties were more prominent in SSc than healthy monocytic EPCs (P = 0.03 for both comparisons). In contrast, incorporation of SSc monocytic EPCs into the tubular structure was less efficient in vitro and in vivo, compared with healthy monocytic EPCs.ConclusionsSSc patients have high numbers of aberrant circulating monocytic EPCs that exert enhanced angiogenesis but are impaired in vasculogenesis. However, these cells apparently cannot overcome the anti-angiogenic environment that characterizes SSc-affected tissues.