[A Case Report of Surgical Resection of a Supraseller Granuloma in a Patient with Erdheim-Chester Disease].

Erdheim-Chester disease(E-CD)is a rare pathology characterized by systematic granulomatosis that occasionally involves the central nervous system. We report about a 68-year-old woman with E-CD who presented with right-side visual disturbance. Magnetic resonance imaging showed a suprasellar tumor that elevated the right optic nerve and involved the right internal carotid and right anterior choroidal arteries. The tumor was partially resected via a trans-Sylvian approach and was histologically diagnosed as a granuloma. Considering the abnormal findings of postoperative X-ray and 99 mTc bone scintigraphy of the long bones, the pathology was diagnosed as E-CD. After surgery, her right-side visual disturbances disappeared. However, 1 year later, she died of systemic infection and heart failure. Histological autopsy findings indicated numerous yellowish nodules in the heart, lung, and kidney with pericardial and pleural effusions and whole-body granulomatosis, including the brain. E-CD is a rare but critical disease. This pathological entity should be considered when encountering cases of intracranial granuloma to ensure its early diagnosis and appropriate treatment. Surgical resection of intracranial granulomas in patients with E-CD may promptly improve neurological dysfunction.

[A Case of Glioblastoma that Appeared One Year after the Removal of Subcortical Hematoma].

Subcortical bleeding from brain tumors is not rare. In the majority of cases, tumors are revealed within a few months after bleeding. We herein report a relatively rare case of glioblastoma(GBM)that appeared one year after the removal of a subcortical hematoma. A 70-year-old woman suddenly began experiencing headache, vomiting, and aphasia. CT revealed a subcortical hematoma in the left superior temporal lobe and subarachnoid bleeding. Neither aneurysms nor abnormal signs suggesting a malignant tumor were noted during cerebral angiography. The hematoma was completely removed via craniotomy, and she was discharged with no neurological deficit.(MRI performed seven months after the surgery showed neither space-occupying lesions in the left temporal lobe nor brain edema. Twelve months after the initial surgery, she had aphasia again. CT and MRI revealed an enhanced mass lesion in the left temporal lobe. Positron emission tomography findings strongly indicated the presence of a malignant tumor. Histology of the tumor after removal showed GBM HDH-1 wild-type with an MIB-1 labelling index of approximately 50%. After the surgery, she underwent extensive local radiation therapy(50 Gy)with chemotherapy(temozolomide). The pathological mechanism underlying the appearance of GBM at the site where subcortical bleeding was previously observed is unclear. GBM may have caused bleeding or may have originated from the brain tissue that was damaged during the first surgery. Follow-up using neuroimaging for one year may be needed when subcortical bleeding is observed.

Prediction of therapeutic response before and during i.v. cyclophosphamide pulse therapy for interstitial lung disease in systemic sclerosis: A longitudinal observational study.

There have been no established parameters to predict responsiveness to i.v. cyclophosphamide (IVCY) pulse therapy in combination with corticosteroids in patients with interstitial lung disease (ILD) related to systemic sclerosis (SSc). This retrospective study was conducted to determine predictive factors for efficacy of IVCY at the time of before and during the treatment. Thirty-two Japanese SSc patients, ever treated for ILD with IVCY in combination with prednisolone, were analyzed retrospectively. We performed detailed time-course analyses of parameters derived from blood samples and pulmonary function tests. With the exclusion of eight unclassified patients, 24 patients were classified into 14 good responders (GR) or 10 poor responders (PR) on the basis of changes in percent predicted diffusing capacity for carbon monoxide (DLco). Pretreatment percent predicted DLco was significantly reduced in PR compared with GR. In addition, serum parameters such as Krebs von den Lungen-6 (KL-6), surfactant protein D (SP-D) and C-reactive protein were significantly higher in PR than in GR. Furthermore, our time-course analyses revealed a transient increase in serum KL-6 levels with a peak at 3 months after the first infusion of cyclophosphamide, which showed no relation to therapeutic efficacy. Moreover, continuously high serum KL-6 levels (>2000 U/mL) and rapid decrease in SP-D levels (<200 ng/mL) during IVCY were remarkably characteristic of PR and GR, respectively. ILD severity/activity before treatment and variability of serum KL-6 and SP-D levels during treatment may be useful to predict therapeutic effects of IVCY on SSc-ILD.

Epithelial Fli1 deficiency drives systemic autoimmunity and fibrosis: Possible roles in scleroderma.

Systemic sclerosis (SSc), or scleroderma, is a multisystem autoimmune disorder characterized by vasculopathy and fibrosis in the skin and internal organs, most frequently in the esophagus and lungs. Hitherto, studies on SSc pathogenesis centered on immune cells, vascular cells, and fibroblasts. Although dysregulated keratinocytes in SSc have been recently reported, the contribution of epithelial cells to pathogenesis remains unexplored. In this study, we demonstrated the induction of SSc-like molecular phenotype in keratinocytes by gene silencing of transcription factor Friend leukemia virus integration 1 (Fli1), the deficiency of which is implicated in SSc pathogenesis. Keratin 14-expressing epithelial cell-specific Fli1 knockout mice spontaneously developed dermal and esophageal fibrosis with epithelial activation. Furthermore, they developed remarkable autoimmunity with interstitial lung disease derived from thymic defects with down-regulation of autoimmune regulator (Aire). Importantly, Fli1 directly regulated Aire expression in epithelial cells. Collectively, epithelial Fli1 deficiency might be involved in the systemic autoimmunity and selective organ fibrosis in SSc. This study uncovers unidentified roles of dysregulated epithelial cells in SSc pathogenesis.

Major differences between human atopic dermatitis and murine models, as determined by using global transcriptomic profiling.

BACKGROUND: Atopic dermatitis (AD) is caused by a complex interplay between immune and barrier abnormalities. Murine models of AD are essential for preclinical assessments of new treatments. Although many models have been used to simulate AD, their transcriptomic profiles are not fully understood, and a comparison of these models with the human AD transcriptomic fingerprint is lacking. OBJECTIVE: We sought to evaluate the transcriptomic profiles of 6 common murine models and determine how they relate to human AD skin. METHODS: Transcriptomic profiling was performed by using microarrays and quantitative RT-PCR on biopsy specimens from NC/Nga, flaky tail, Flg-mutated, ovalbumin-challenged, oxazolone-challenged, and IL-23-injected mice. Gene expression data of patients with AD, psoriasis, and contact dermatitis were obtained from previous patient cohorts. Criteria of a fold change of 2 or greater and a false discovery rate of 0.05 or less were used for gene arrays. RESULTS: IL-23-injected, NC/Nga, and oxazolone-challenged mice show the largest homology with our human meta-analysis-derived AD transcriptome (37%, 18%, 17%, respectively). Similar to human AD, robust TH1, TH2, and also TH17 activation are seen in IL-23-injected and NC/Nga mice, with similar but weaker inflammation in ovalbumin-challenged mice. Oxazolone-challenged mice show a TH1-centered reaction, and flaky tail mice demonstrate a strong TH17 polarization. Flg-mutated mice display filaggrin downregulation without significant inflammation. CONCLUSION: No single murine model fully captures all aspects of the AD profile; instead, each model reflects different immune or barrier disease aspects. Overall, among the 6 murine models, IL-23-injected mice best simulate human AD; still, the translational focus of the investigation should determine which model is most applicable.

Tamibarotene Ameliorates Bleomycin-Induced Dermal Fibrosis by Modulating Phenotypes of Fibroblasts, Endothelial Cells, and Immune Cells.

Tamibarotene (Am80) is a synthetic retinoid that modulates the pathologic processes of various autoimmune and inflammatory diseases and their animal models. We here investigated the therapeutic potential of Am80 against systemic sclerosis using its animal models. Am80 significantly attenuated dermal and hypodermal fibrosis in bleomycin (BLM)-treated mice and tight skin 1 mice, respectively. Consistently, Am80 significantly suppressed the expression of various molecules related to tissue fibrosis, including transforming growth factor-ß1, connective tissue growth factor, IL-4, IL-10, IL-13, IL-17A, tumor necrosis factor-α, IFN-γ, and monocyte chemotactic protein 1 in the lesional skin of BLM-treated mice. Furthermore, Am80 decreased the proportion of effector T cells, while increasing that of naïve T cells among CD4+ T cells in the draining lymph nodes of BLM-treated mice. Moreover, a series of BLM-induced pathologic events, including endothelial-to-mesenchymal transition; ICAM-1 expression in endothelial cells; the infiltration of macrophages, mast cells, and lymphocytes; and M2 macrophage differentiation, were attenuated by Am80. Importantly, Am80 directly reversed the profibrotic phenotype of transforming growth factor-ß1-treated dermal fibroblasts, suppressed ICAM-1 expression in endothelial cells, and promoted M1 macrophage differentiation in vitro. Collectively, Am80 inhibits the development of experimental dermal fibrosis by reversing the profibrotic phenotype of various cell types and would be a candidate for therapeutic drugs against dermal fibrosis of systemic sclerosis.

Diverse activation and differentiation of multiple B-cell subsets in patients with atopic dermatitis but not in patients with psoriasis.

BACKGROUND: Atopic dermatitis (AD) and psoriasis pathogeneses involve skin barrier impairment and immune dysregulation; however, the contribution of B-cell imbalances to these diseases has not yet been determined. OBJECTIVE: We sought to quantify B-cell populations and antibody-secreting cells in the blood of patients with AD, patients with psoriasis, and control subjects. METHODS: We studied 34 adults with moderate-to-severe AD (mean SCORAD score, 65), 24 patients with psoriasis (mean Psoriasis Area and Severity Index score, 16), and 27 healthy subjects using an 11-color flow cytometric antibody panel. IgD/CD27 and CD24/CD38 core gating systems were used to determine frequencies of plasmablasts and naive, memory, transitional, and activated B cells. RESULTS: We measured increased CD19(+)CD20(+) B-cell counts in the skin and blood of patients with AD (P < .01). Significantly higher frequencies of chronically activated CD27(+) memory and nonswitched memory B cells were observed in patients with AD (P < .05), with lower values of double-negative populations (4% for patients with AD vs. 7% for patients with psoriasis [P = .001] and 6% for control subjects [P = .02]). CD23 expression was highest in patients with AD and correlated with IgE levels (P < .01) and disease severity (r = 0.6, P = .0002). Plasmablast frequencies and IgE expression were highest in all memory subsets of patients with AD (P < .01). Finally, CD19(+)CD24(++)CD38(++) transitional and CD19(+)CD24(-)CD38(-) new memory B-cell counts were higher in patients with AD versus those in patients with psoriasis (2.8% vs. 1.4% [P = .001] and 9.2% vs. 5.7% [P = .02], respectively). CONCLUSIONS: AD is accompanied by systemic expansion of transitional and chronically activated CD27(+) memory, plasmablast, and IgE-expressing memory subsets. These data create a critical basis for the future understanding of this debilitating skin disease.

Circulating galectin-1 concentrations in systemic sclerosis: potential contribution to digital vasculopathy.

AIM: To determine serum galectin-1 levels and their clinical associations in patients with systemic sclerosis (SSc). METHOD: Serum galectin-1 levels were examined by enzyme-linked immunosorbent assay in 66 patients with SSc and 24 healthy individuals. RESULTS: No significant differences were observed in serum galectin-1 levels between patients with SSc (9.4 ± 5.6 ng/mL), and healthy individuals (8.9 ± 1.3 ng/mL). Among patients with SSc, no significant differences were seen in serum galectin-1 levels between those with diffuse cutaneous SSc (8.8 ± 5.7 ng/mL; n = 31) and those with limited cutaneous SSc (10.0 ± 5.4 ng/mL; n = 35). Patients with SSc who had increased galectin-1 levels less often had pitting scars/digital ulcers than those with normal galectin-1 levels (17% vs. 49%; P < 0.01). Consistently, galectin-1 levels were significantly lower in SSc patients with pitting scars/digital ulcers than in those without pitting scars/digital ulcers (6.9 ± 4.8 vs. 10.9 ± 5.5 ng/mL; P < 0.01). CONCLUSION: These results suggest that galectin-1 is a protective factor against the development of digital vasculopathy in SSc. In addition, measurement of serum galectin-1 levels may be useful for risk stratification for the development of digital vasculopathy in the early phase of SSc.

Effect of ambrisentan on peripheral circulation in patients with systemic sclerosis.

Systemic sclerosis (SSc) is characterized by disturbed blood circulation. The effect of ambrisentan, an endothelin-A receptor-selective antagonist, on impaired peripheral circulation in SSc remains largely elusive. Here we show SSc patients, whose clinical symptoms such as cyanosis and Raynaud's phenomenon, were ameliorated by the treatment with ambrisentan. Additionally, objective evaluations with thermography showed improvement of hand coldness in steady-state and cold challenge tests. Ambrisentan might have a potential to improve peripheral circulation in SSc.

The Asian atopic dermatitis phenotype combines features of atopic dermatitis and psoriasis with increased TH17 polarization.

BACKGROUND: Atopic dermatitis (AD) shows very high prevalence in Asia, with a large unmet need for effective therapeutics. Direct comparisons between European American (EA) and Asian patients with AD are unavailable, but earlier blood studies detected increased IL-17(+)-producing cell counts in Asian patients with AD. OBJECTIVE: We sought to characterize the Asian AD skin phenotype and compare it with the EA AD skin phenotype. METHODS: We performed genomic profiling (real-time PCR) and immunohistochemistry on lesional and nonlesional biopsy specimens from 52 patients with AD (25 EAs and 27 Asians), 10 patients with psoriasis (all EAs), and 27 healthy subjects (12 EAs and 15 Asians). RESULTS: Although disease severity/SCORAD scores were similar between the AD groups (58.0 vs 56.7, P = .77), greater acanthosis, higher Ki67 counts, and frequent parakeratosis were characteristics of lesional epidermis from Asian patients with AD (P < .05). Most (24/27) Asian patients had high IgE levels. A principal component analysis using real-time PCR data clustered the Asian AD phenotype between the EA AD and psoriasis phenotypes. TH2 skewing characterized both Asian and EA patients with AD but not patients with psoriasis. Significantly higher TH17 and TH22 (IL17A, IL19, and S100A12 in lesional and IL-22 in nonlesional skin; P < .05) and lower TH1/interferon (CXCL9, CXCL10, MX1, and IFNG in nonlesional skin; P < .05) gene induction typified AD skin in Asian patients. CONCLUSION: The Asian AD phenotype presents (even in the presence of increased IgE levels) a blended phenotype between that of EA patients with AD and those with psoriasis, including increased hyperplasia, parakeratosis, higher TH17 activation, and a strong TH2 component. The relative pathogenic contributions of the TH17 and TH2 axes in creating the Asian AD phenotype need to be tested in future clinical trials with appropriate targeted therapeutics.

Alopecia areata profiling shows TH1, TH2, and IL-23 cytokine activation without parallel TH17/TH22 skewing.

BACKGROUND: Alopecia areata (AA) is a common T cell-mediated disorder with limited therapeutics. A molecular profile of cytokine pathways in AA tissues is lacking. Although studies have focused on TH1/IFN-γ responses, several observations support a shared genetic background between AA and atopy. OBJECTIVE: We sought to define the AA scalp transcriptome and associated biomarkers with comparisons with atopic dermatitis (AD) and psoriasis. METHODS: We performed microarray and RT-PCR profiling of 27 lesional and 17 nonlesional scalp samples from patients with AA for comparison with normal scalp samples (n = 6). AA gene expression was also compared with samples from patients with lesional or nonlesional AD and those with psoriasis. A fold change of greater than 1.5 and a false discovery rate of less than 0.05 were used for differentially expressed genes (DEGs). RESULTS: We established the AA transcriptomes (lesional vs nonlesional: 734 DEGs [297 upregulated and 437 downregulated]; lesional vs normal: 4230 DEGs [1980 upregulated and 2250 downregulated]), including many upregulated immune and downregulated hair keratin genes. Equally impressive as upregulation in TH1/interferon markers (IFNG and CXCL10/CXCL9) were those noted in TH2 (IL13, CCL18, CCL26, thymic stromal lymphopoietin, and periostin), TH9/IL-9, IL-23 (p40 and p19), and IL-16 mediators (all P < .05). There were no increases in TH17/TH22 markers. Hair keratin (KRT) expressions (ie, KRT86 and KRT85) were significantly suppressed in lesional skin. Greater scalp involvement (>25%) was associated with greater immune and keratin dysregulation and larger abnormalities in nonlesional scalp samples (ie, CXCL10 and KRT85). CONCLUSIONS: Our data associate the AA signature with TH2, TH1, IL-23, and IL-9/TH9 cytokine activation, suggesting consideration of anti-TH2, anti-TH1, and anti-IL-23 targeting strategies. Similar to psoriasis and AD, clinical trials with selective antagonists are required to dissect key pathogenic pathways.

Progranulin Overproduction Due to Fli-1 Deficiency Contributes to the Resistance of Dermal Fibroblasts to Tumor Necrosis Factor in Systemic Sclerosis.

OBJECTIVE: Progranulin is a growth factor that is active in wound repair and is an antagonist of tumor necrosis factor (TNF) receptors, regulating fibroblast activation, angiogenesis, and inflammation. Because long-standing activation of gene programs related to wound healing is a hallmark of systemic sclerosis (SSc), we sought to investigate the role of progranulin in SSc. METHODS: Progranulin expression levels in human and murine skin samples were determined by immunohistochemical analysis and quantitative reverse transcription-polymerase chain reaction. The role of progranulin in fibroblast activation was examined using a gene-silencing technique. Progranulin levels in serum obtained from 60 patients with SSc and 16 healthy control subjects were determined by enzyme-linked immunosorbent assay. RESULTS: Progranulin expression was increased in SSc dermal fibroblasts compared with normal dermal fibroblasts, both in vivo and in vitro. Transcription factor Fli-1, a deficiency of which is involved in the activation of SSc dermal fibroblasts, served as a potent repressor of the progranulin gene, and Fli-1(+/-) mice and bleomycin-treated wild-type mice exhibited up-regulated expression of progranulin in dermal fibroblasts. SSc dermal fibroblasts were resistant to the antifibrotic effect of TNF, but this resistance was reversed by gene silencing of progranulin. Serum progranulin levels were elevated in patients with early diffuse cutaneous SSc (dcSSc), especially in those with inflammatory skin symptoms, and were positively correlated with the C-reactive protein level. CONCLUSION: Progranulin overproduction due to Fli-1 deficiency may contribute to the constitutive activation of SSc dermal fibroblasts by antagonizing the antifibrotic effect of TNF. Progranulin may also be involved in the inflammatory process associated with progressive skin sclerosis in early dcSSc.

Early pediatric atopic dermatitis shows only a cutaneous lymphocyte antigen (CLA)(+) TH2/TH1 cell imbalance, whereas adults acquire CLA(+) TH22/TC22 cell subsets.

BACKGROUND: Identifying differences and similarities between cutaneous lymphocyte antigen (CLA)(+) polarized T-cell subsets in children versus adults with atopic dermatitis (AD) is critical for directing new treatments toward children. OBJECTIVE: We sought to compare activation markers and frequencies of skin-homing (CLA(+)) versus systemic (CLA(-)) "polar" CD4 and CD8 T-cell subsets in patients with early pediatric AD, adults with AD, and control subjects. METHODS: Flow cytometry was used to measure CD69/inducible costimulator/HLA-DR frequency in memory cell subsets, as well as IFN-γ, IL-13, IL-9, IL-17, and IL-22 cytokines, defining TH1/cytotoxic T (TC) 1, TH2/TC2, TH9/TC9, TH17/TC17, and TH22/TC22 populations in CD4 and CD8 cells, respectively. We compared peripheral blood from 19 children less than 5 years old and 42 adults with well-characterized moderate-to-severe AD, as well as age-matched control subjects (17 children and 25 adults). RESULTS: Selective inducible costimulator activation (P < .001) was seen in children. CLA(+) TH2 T cells were markedly expanded in both children and adults with AD compared with those in control subjects, but decreases in CLA(+) TH1 T-cell numbers were greater in children with AD (17% vs 7.4%, P = .007). Unlike in adults, no imbalances were detected in CLA(-) T cells from pediatric patients with AD nor were there altered frequencies of TH22 T cells within the CLA(+) or CLA(-) compartments. Adults with AD had increased frequencies of IL-22-producing CD4 and CD8 T cells within the skin-homing population, compared with controls (9.5% vs 4.5% and 8.6% vs 2.4%, respectively; P < .001), as well as increased HLA-DR activation (P < .01). CONCLUSIONS: These data suggest that TH2 activation within skin-homing T cells might drive AD in children and that reduced counterregulation by TH1 T cells might contribute to excess TH2 activation. TH22 "spreading" of AD is not seen in young children and might be influenced by immune development, disease chronicity, or recurrent skin infections.

Efficacy comparison of ustekinumab between anti-tumor necrosis factor-α drug-naïve and anti-tumor necrosis factor-α drug-resistant Japanese psoriasis cases.

Ustekinumab is highly efficacious for psoriasis; however, it has not been fully clarified whether previous failure in anti-tumor necrosis factor-α (TNF-α) therapy affects the treatment response with ustekinumab. Therefore, we evaluated the efficacy of ustekinumab in anti-TNF-α-naïve and anti-TNF-α-resistant cases and compared the clinical efficacies of adalimumab and ustekinumab in biologic naïve cases. Thirty-five patients with plaque psoriasis who showed resistance to conventional therapies were enrolled; 26 patients, who had never been treated with biologics, were allocated to ustekinumab or adalimumab; nine patients who failed to achieve psoriasis area and severity index (PASI) 50 at week 16 with one or two TNF-α antagonists were switched to ustekinumab. The end of the study was defined as 52 weeks after starting the first biologic for anti-TNF-α-naïve patients and after switching to ustekinumab for anti-TNF-α-resistant patients. The primary outcome measurement was the percentage of patients achieving PASI75 at week 16. In patients treated with ustekinumab, 87.5% of anti-TNF-α-naïve and 77.8% of anti-TNF-α-resistant cases achieved a PASI75 response at week 16, and no statistically significant difference was found between the treatment response rates (P = 0.60). When comparing the treatment efficacy of ustekinumab and adalimumab among anti-TNF-α-naïve patients, there was also no statistically significant difference in PASI75 achievement rates (87.5 vs. 83.3%, P = 0.79). Our study suggests that ustekinumab can be considered as a first-line biologic for psoriasis and a rescue therapy for anti-TNF-α-resistant cases.

Polyclonal hyperviscosity syndrome in IgG4-related disease and associated conditions.

Polyclonal hyperviscosity syndrome (HVS) is rare and has been reported in various disorders of immune dysregulation and lymphoid hyperplasia. IgG4-Related Disease (IgG4-RD) is an emerging disorder often associated with exuberant hypergammaglobulinemia, and this review of seven cases establishes IgG4-RD as an important cause of polyclonal HVS.

Association of anti-RNA polymerase III antibody and malignancy in Japanese patients with systemic sclerosis.

Patients with systemic sclerosis (SSc) have an increased risk of malignancy compared with the general population. Recently, SSc patients with anti-RNA polymerase III antibody have been reported to have an increased risk of malignancy as compared with those with other disease-specific autoantibodies in US, European and Australian populations. Therefore, we studied the relationship between disease-specific autoantibodies and malignancy in 261 Japanese SSc patients. The prevalence of malignancy was significantly higher in patients with anti-RNA polymerase III antibody (7/22, 31.8%) than in those with anti-topoisomerase I antibody (2/82, 2.4%) and in those with anticentromere antibody (8/137, 5.8%). Importantly, among seven patients with anti-RNA polymerase III antibody and malignancy, three patients (42.9%) developed malignancy from 6 months before to 12 months after SSc onset. Thus, malignancy complication in Japanese SSc patients with anti-RNA polymerase III antibody is as high as that in other races, suggesting that SSc patients with anti-RNA polymerase III antibody share the same pathological process among different ethnic groups.

Endothelin receptor blockade ameliorates vascular fragility in endothelial cell-specific Fli-1-knockout mice by increasing Fli-1 DNA binding ability.

OBJECTIVE: It is generally accepted that blockade of endothelin receptors has potentially beneficial effects on vasculopathy associated with systemic sclerosis (SSc). The aim of this study was to clarify the molecular mechanism underlying these effects using endothelial cell-specific Fli-1-knockout (Fli-1 ECKO) mice, an animal model of SSc vasculopathy. METHODS: Levels of messenger RNA for target genes and the expression and phosphorylation levels of target proteins were determined in human and murine dermal microvascular endothelial cells by real-time quantitative reverse transcription-polymerase chain reaction and immunoblotting, respectively. The binding of Fli-1 to the target gene promoters was evaluated using chromatin immunoprecipitation. Expression levels of Fli-1 and α-smooth muscle actin in murine skin were evaluated using immunohistochemistry. Vascular structure and permeability were evaluated in mice injected with fluorescein isothiocyanate-dextran and Evans blue dye, respectively. RESULTS: In human dermal microvascular endothelial cells, endothelin 1 induced phosphorylation of Fli-1 at Thr(312) through the sequential activation of c-Abl and protein kinase Cδ, leading to a decrease in Fli-1 protein levels as well as a decrease in binding of Fli-1 to the target gene promoters, whereas bosentan treatment reversed those effects. In Fli-1 ECKO mice, 4 weeks of treatment with bosentan increased endothelial Fli-1 expression, resulting in vascular stabilization and the restoration of impaired leaky vessels. CONCLUSION: The vascular fragility of Fli-1 ECKO mice was improved by bosentan through the normalization of Fli-1 protein levels and activity in endothelial cells, which may explain, in part, the mechanism underlying the beneficial effects of endothelin receptor blockade on SSc vasculopathy.

Amelioration of tissue fibrosis by toll-like receptor 4 knockout in murine models of systemic sclerosis.

OBJECTIVE: Bleomycin-induced fibrosis and the tight skin (TSK/+) mouse are well-established experimental murine models of human systemic sclerosis (SSc). Growing evidence has demonstrated the pivotal role of Toll-like receptors (TLRs) in several autoimmune inflammatory diseases, including SSc. This study was undertaken to determine the role of TLR-4 in the fibrotic processes in these murine models. METHODS: We generated a murine model of bleomycin-induced SSc using TLR-4(-/-) mice and TLR-4(-/-) ;TSK/+ mice. The mechanisms by which TLR-4 contributes to pathologic tissue fibrosis were investigated in these 2 models by histologic examination, hydroxyproline assay, enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and flow cytometry. RESULTS: Dermal and lung fibrosis was attenuated in bleomycin-treated TLR-4(-/-) mice compared with their wild-type counterparts. Inflammatory cell infiltration, expression of various inflammatory cytokines, and pathologic angiogenesis induced by bleomycin treatment were suppressed with TLR-4 deletion. Furthermore, the increased expression of interleukin-6 (IL-6) in fibroblasts, endothelial cells, and immune cells in response to bleomycin in vivo and to lipopolysaccharide in vitro was notably abrogated in the absence of TLR-4. Moreover, TLR-4 deletion was associated with alleviated B cell activation and skew toward a Th2/Th17 response against bleomycin treatment. Importantly, in TSK/+ mice, another SSc murine model, TLR-4 abrogation attenuated hypodermal fibrosis. CONCLUSION: These results indicate the pivotal contribution of TLR-4 to the pathologic tissue fibrosis of SSc murine models. Our results indicate the critical role of TLR-4 signaling in the development of tissue fibrosis, suggesting that biomolecular TLR-4 targeting might be a potential therapeutic approach to SSc.