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Thymoma is recognized to be complicated with autoimmune diseases, such as myasthenia gravis, pemphigus vulgaris and bullous pemphigoid. Abnormal regulation of autoreactive lymphocytes may be involved in the pathogenesis of the autoimmune diseases. The association of thymoma and lichen planus (LP) is relatively rare. Among 50 patients with LP, we identified three patients with LP accompanied by thymoma (6%; 3/50) in our department from 2004 to 2014. This is the first report identifying the frequency of thymoma accompanied by LP among patients with LP. We herein report three cases of LP accompanied by thymoma along with clinical and histological features. In addition, we summarize 29 LP patients accompanied by thymoma previously reported in the English-language published works. Regarding the complications, hypogammaglobulinemia accompanied 58.6% (17/29) of patients diagnosed with Good's syndrome. Alopecia was present in 13.8% (4/29) of patients, and myasthenia gravis was present in 17.2% (5/29) of patients with LP and thymoma. Among the 27 patients with thymectomy, only 25.9% (7/27) experienced the improvement of LP, suggesting that thymectomy may not be effective for the lesions of LP. Treatment-resistant LP was reported in 54.2% (13/24) of patients. In all our cases, oral lesions were intractable to treatment with oral predonisone and topical steroids and/or tacrolimus. It is important for dermatologists to recognize the clinical characteristics of the patients with both LP and thymoma., (© 2015 Japanese Dermatological Association.)

LEOPARD syndrome (LS) is an autosomal dominant condition with multiple anomalies, including multiple lentigines. LS is caused by mutations in PTPN11, encoding the protein tyrosine phosphatase, SHP-2. We report here 2 unrelated Japanese cases of LS with different PTPN11 mutations (p.Y279C and p.T468P). To elucidate the pathogenesis of multiple lentigines in LS, ultrastructural and immunohistochemical analyses of lentigines and non-lesional skin were performed. Numerous mature giant melanosomes in melanocytes and keratinocytes were observed in lentigines. In addition, the levels of expression of endothelin-1 (ET-1), phosphorylated Akt, mTOR and STAT3 in the epidermis in lentigines were significantly elevated compared with non-lesional skin. In in vitro assays, melanin synthesis in human melanoma cells expressing SHP-2 with LS-associated mutations was higher than in cells expressing normal SHP-2, suggesting that LS-associated SHP-2 mutations might enhance melanin synthesis in melanocytes, and that the activation of Akt/mTOR signalling may contribute to this process.

The precise mechanisms of tissue fibrosis have not yet been elucidated in systemic sclerosis (SSc). However, studies of the regulation of DNA methylation, the most widely studied epigenetic mechanism, have confirmed the involvement of the TET family proteins, recently identified DNA demethylases, in the pathogenesis of SSc. The mRNA levels of TET family members were compared in normal and SSc fibroblasts. The effects of hypoxia and siRNA specific to HIF-1α on TET expression were also examined. Global methylation status was analysed by LUMA. The presence of 5-hydroxymethylcytosine (5hmC) in SSc was examined by immunohistochemistry. The level of TET1 mRNA in SSc fibroblasts was elevated by 1.68 fold compared with that of normal fibroblasts, but the expression levels of TET2 and TET3 were comparable between both cell types. The expression levels of DNMT1 and DNMT3B mRNA have a tendency to elevate in SSc fibroblasts. Among TET family members, the expression of TET1 was exclusively induced by hypoxia via HIF-1α-independent pathways in SSc fibroblasts, but not in normal fibroblasts. The methylation level was decreased in SSc fibroblasts relative to normal fibroblasts, and 5hmC was present in dermal fibroblasts of skin sections from patients with SSc. TET1 expression in SSc fibroblasts was abnormally regulated in the hypoxic environment and accompanied by global DNA hypomethylation, suggesting the involvement of aberrant DNA methylation in the pathogenesis of SSc., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The purpose of this study was to develop an optimizing program of scanning parameters for double inversion recovery (DIR) MRI. The optimization algorithm consists of the following steps: (1) obtaining the initial parameters (TR, TE, and T1 values of the two attenuated tissues); (2) iterative calculation for minimization of errors; and (3) determination of the optimized TI(1st) and TI(2nd). To evaluate the developed algorithm, we performed the phantom and simulation studies using the phantoms which were imitated T1 values of white and gray matters and cerebrospinal fluid. In addition, white matter attenuated inversion recovery (WAIR) and gray matter attenuated inversion recovery (GAIR) images were obtained by optimized scan parameters in one volunteer. The developed algorithm could calculate the optimized TI(1st) and TI(2nd) values at once. Results of summation of signal intensity (SI) of two attenuated tissues shows that the SI of the two tissues were well-attenuated using the theoretical values which were calculated using the developed algorithm. The correlation coefficient of the SI of the phantom of the gray matter between actual and simulation measurements was r=0.997. The SI obtained by actual measurements well correlated with the SI obtained by the simulation measurements. The WAIR and GAIR images in the volunteer were well enhanced gray or white matters. We thus conclude that it is possible to calculate the optimized parameters for the DIR-MRI using the developed algorithm.

Botulinum toxin A (BTX-A) blocks the release of acetylcholine vesicles into the synaptic space, and has been clinically used for aesthetic indications, neuromuscular disorders and hyperhidrosis. Several studies have demonstrated that BTX-A enhanced the blood flow and improved ischemia in animal models. Our objective was to assess the effects of BTX-A on cutaneous ischemia-reperfusion (I/R) injuries, mimicking decubitus ulcers. The administration of BTX-A in I/R areas significantly inhibited the formation of decubitus-like ulcer in cutaneous I/R injury mouse model. The number of CD31(+) vessels and αSMA(+) pericytes or myofibroblasts in wounds were significantly increased in the I/R mice treated with BTX-A. The hypoxic area and the number of oxidative stress-associated DNA-damaged cells and apoptotic cells in the I/R sites were reduced by BTX-A administration. In an in vitro assay, BTX-A significantly prevented the oxidant-induced intracellular accumulation of reactive oxygen species (ROS) in vascular endothelial cells. Furthermore, the administration of BTX-A completely suppressed the ulcer formation in an intermittent short-time cutaneous I/R injury model. These results suggest that BTX-A might have protective effects against ulcer formation after cutaneous I/R injury by enhancing angiogenesis and inhibiting hypoxia-induced cellular damage. Exogenous application of BTX-A might have therapeutic potential for cutaneous I/R injuries.

Localized scleroderma (LSc) primarily affects skin, whereas systemic sclerosis (SSc) affects skin and various internal organs. LSc and SSc are considered to be basically different diseases, and there is no transition between them. However, LSc and SSc have several common characteristics, including endothelial cell dysfunction, immune activation, and excess fibrosis of the skin, and there exist several SSc cases complicated with LSc during the course of SSc. Clinical and laboratory characteristics of SSc patients with LSc remain unclear. We investigated the clinical and laboratory features of 8 SSc patients with LSc among 220 SSc patients (3.6%). The types of LSc included plaque (5/8), guttate (2/8), and linear type (1/8). All cases were diagnosed as having SSc within 5 years before or after the appearance of LSc. In three cases of SSc with LSc (37.5%), LSc skin lesions preceded clinical symptoms of SSc. Young age, negative antinuclear antibody, and positive anti-RNA polymerase III antibody were significantly prevalent in SSc patients with LSc. The positivity of anticentromere antibody tended to be prevalent in SSc patients without LSc. No significant difference in the frequency of complications, such as interstitial lung disease, reflux esophagitis, and pulmonary artery hypertension, was observed. The awareness of these characteristic of SSc with LSc are essential to establish an early diagnosis and treatment., (© 2015 Japanese Dermatological Association.)

Anti-RNA polymerase III antibody (RNAP) is primarily detected in diffuse cutaneous type systemic sclerosis (dcSSc) patients and strongly associated with renal crisis. Additionally, there has been increasing evidence that cancer in SSc patients is associated with RNAP. The aim of this study was to examine the demographic and clinical features of SSc patients with RNAP. Among 246 SSc patients, 5.7% were positive for RNAP, 20.7% were positive for anti-topoisomerase I antibody (Topo I) alone and 39.4% were positive for anticentromere antibody (ACA) alone. The modified Rodnan total skin score (mRTSS) in SSc patients with RNAP (19.1 ± 2.6) was significantly higher than those in SSc patients with Topo I (11.5 ± 1.1) and patients with ACA (4.4 ± 0.4). Furthermore, among SSc patients with RNAP, the levels of RNAP were positively correlated with mRTSS. Renal crisis is also significantly more prevalent in SSc patients with RNAP than patients without RNAP. Male sex, dcSSc subtype, digital vasculopathy, including digital ulcers and acro-osteolysis, interstitial lung disease and rheumatoid arthritis complications were prevalent in SSc patients with RNAP and patients with Topo-I. Primary biliary cirrhosis and Sjögren's syndrome were more in SSc patients with RNAP and patients with ACA compared with patients with Topo 1. No significant difference in the frequency of complications, including Raynaud's phenomenon, pulmonary artery hypertension and malignancy was observed between the three groups. Thus, measurement of RNAP in SSc patients is useful for the diagnosis and risk stratification of severe manifestation, such as renal crisis and severe skin sclerosis., (© 2014 Japanese Dermatological Association.)

Autoimmune thyroid disorders (AITD) are characterized by the impairment of the thyroid gland as a result of systemic or organ-specific autoimmune disorders, and the presence of antithyroid autoantibodies, such as antithyroglobulin antibody (AbTg) and antithyroid peroxidase antibody (AbTPO). Several studies have reported the association of AITD with systemic sclerosis (SSc). However, none of those studies analyzed the association between AITD and skin sclerosis in SSc patients. The aim of this study was to examine the demographic and clinical features of SSc patients with AITD treated in our department. Of a total of 210 SSc patients, we identified 30 with AITD (14.3%), including 29 with Hashimoto's disease (13.8%) and one patient with Graves' disease (0.5%), indicating that hypothyroidism was more common among SSc patients with AITD. All patients with AITD were female, and anticentromere antibody positivity, the complication of Sjögren's syndrome, severe facial skin sclerosis and atrophy of the thyroid gland were significantly prevalent in SSc patients with AITD. SSc patients with such clinical features may be at high risk of AITD and require regular follow up of thyroid function including ultrasonography and the examination of serum hormone levels to start an early treatment., (© 2014 Japanese Dermatological Association.)

Atypical progeroid syndrome (APS), including atypical Werner syndrome (AWS), is a progeroid syndrome involving heterozygous mutations in the LMNA gene encoding the nuclear protein lamin A/C. We report the first Japanese case of APS/AWS with a LMNA mutation (p.D300N). A 53-year-old Japanese man had a history of recurrent severe cardiovascular diseases as well as brain infarction and hemorrhages. Although our APS/AWS patient had overlapping features with Werner syndrome (WS), such as high-pitched voice, scleroderma, lipoatrophy and atherosclerosis, several cardinal features of WS, including short stature, premature graying/alopecia, cataract, bird-like face, flat feet, hyperkeratosis on the soles and diabetes mellitus, were absent. In immunofluorescence staining and electron microscopic analyses of the patient's cultured fibroblasts, abnormal nuclear morphology, an increase in small aggregation of heterochromatin and a decrease in interchromatin granules in nuclei of fibroblasts were observed, suggesting that abnormal nuclear morphology and chromatin disorganization may be associated with the pathogenesis of APS/AWS., (© 2014 Japanese Dermatological Association.)

Homocysteine is a sulfhydryl-containing amino acid that is derived from dietary methionine, and there has been increasing evidence that elevated plasma homocysteine levels are associated with increased risk of cardiovascular diseases, including carotid, coronary and peripheral arterial disease (PAD). The association of plasma homocysteine levels with peripheral vascular involvements, such as Raynaud phenomenon (RP), digital ulcers (DU) in systemic sclerosis (SSc) patients has not been well studied. The objective of this study was to examine plasma homocysteine levels and their clinical associations in patients with SSc. Plasma homocysteine levels in 151 Japanese patients with SSc and 20 healthy controls were examined. No significant differences were observed in plasma homocysteine levels between SSc patients and healthy individuals. Demographic and clinical features of the SSc patients revealed that severe skin sclerosis, anti-topoisomerase I antibody positivity, complications of DU, acro-osteolysis (AO) and interstitial lung disease (ILD) were significantly more prevalent among the patients with elevated plasma homocysteine levels. The plasma homocysteine levels were positively correlated with modified Rodnan total skin score. The plasma homocysteine levels in the SSc patients with DU, AO and ILD were significantly higher than those in the SSc without DU, AO and ILD, respectively. Plasma homocysteine levels did not correlate with either the mean or max intima-media thickness (IMT) or plaque score, suggesting that plasma homocysteine levels might not be associated with carotid artery atherosclerosis in SSc patients. The measurement of plasma homocysteine levels in SSc patients might be useful for the risk stratifications of severe skin sclerosis, DU and AO., (© 2014 Japanese Dermatological Association.)

Nephrogenic systemic fibrosis (NSF) is characterized by systemic fibrosis and abnormal calcification in patients with severe renal dysfunction. It is considered that gadolinium (Gd)-containing contrast agents used for magnetic resonance imaging trigger the development of NSF. However, the causative role of Gd and the mechanism of Gd-induced fibrosis and calcification in NSF are unknown. Recently, it has been known that endothelin-1 (ET-1)/ET receptor (ETR) signalling regulates fibrosis and calcification. The objective was to elucidate the role of ET-1/ETR signalling in Gd-induced fibrosis and calcification in NSF. First, we demonstrated that Gd enhanced proliferation and calcification of human adipose tissue-derived mesenchymal stem cells (hMSC) in vitro. Next, we examined the expression of ET-1 and ETR-A in hMSC using proliferation or calcification assay. ET-1 and ETR-A expression in hMSC treated with Gd were elevated. ET-1/ETR signalling inhibitor, bosentan, inhibited Gd-induced proliferation and calcification of hMSC. In addition, bosentan inhibited Gd-induced phosphorylation of ERK and Akt in hMSC. Plasma ET-1 levels of the patients were significantly higher than these of normal individuals and systemic sclerosis patients. In immunofluorescence staining, the expression of ETR-A in fibroblasts in dermal fibrosis lesion of NSF was increased. We conclude that Gd induces proliferation and calcification of hMSC via enhancement of ET-1/ETR signalling. Our results contribute to understand the pathogenesis of NSF., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Our research group recently demonstrated that pericytes are major sources of the secreted glycoprotein and integrin ligand lactadherin (MFG-E8) in B16 melanoma tumors, and that MFG-E8 promotes angiogenesis via enhanced PDGF-PDGFRβ signaling mediated by integrin-growth factor receptor crosstalk. However, sources of MFG-E8 and its possible roles in skin physiology are not well characterized. The objective of this study was to characterize the involvement of MFG-E8 in skin wound healing. In the dermis of normal murine and human skin, accumulations of MFG-E8 were found around CD31(+) blood vessels, and MFG-E8 colocalized with PDGFRβ(+), αSMA(+), and NG2(+) pericytes. MFG-E8 protein and mRNA levels were elevated in the dermis during full-thickness wound healing in mice. MFG-E8 was diffusely present in granulation tissue and was localized around blood vessels. Wound healing was delayed in MFG-E8 knockout mice, compared with the wild type, and myofibroblast and vessel numbers in wound areas were significantly reduced in knockout mice. Inhibition of MFG-E8 production with siRNA attenuated the formation of capillary-like structures in vitro. Expression of MFG-E8 in fibrous human granulation tissue with scant blood vessels was less than that in granulation tissue with many blood vessels. These findings suggest that MFG-E8 promotes cutaneous wound healing by enhancing angiogenesis., (Copyright © 2014 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Patients with systemic sclerosis (SSc) usually develop Raynaud's phenomenon, persistent digital ischemia and sometimes develop digital ulcers (DU). Several studies have reported an association of carotid artery atherosclerosis with SSc by evaluating carotid intima-media thickness (IMT) in SSc patients. However, none of those studies analyzed the association between DU and carotid artery atherosclerosis in SSc patients. We examined the association of carotid artery atherosclerosis with digital ulcers by comparing SSc patients with (n = 48, 29.5%) and without (n = 206, 70.5%) DU. The demographic and clinical features of the SSc patients showed that young age, male sex, anti-topoisomerase I antibody positivity, severe skin sclerosis, interstitial lung disease complication and cardiac involvements were significantly prevalent in patients with DU. In addition, diffuse cutaneous type, anti-RNA polymerase III antibody positivity and severe skin sclerosis are more frequent in SSc patients with DU at the extensor surface of joints than SSc patients with DU at the digital tip. There were no differences in serum lipid level, carotid IMT or plaque score between SSc patients with and without DU, suggesting that atherosclerotic changes are not primarily involved in the development of DU., (© 2014 Japanese Dermatological Association.)

Blepharochalasis is a rare disorder characterized by recurrent episodic swelling of eyelids, eventually leading to atrophy of skin. Although immunological mechanisms may be involved in the degradation of elastic fibers, the pathogenesis is not well characterized. We report a 10-year-old Japanese boy with an 11-month history of the swelling of bilateral upper eyelids with atrophic skin. Attacks of non-painful swelling in eyelids with erythema have recurred several times a month and lasted for 2-3 days. Histological examination revealed perivascular and interstitial infiltration of lymphocytes in the dermis. Elastica Van Gieson staining showed a marked decrease of elastic fibers throughout the dermis. Results of direct and indirect immunofluorescence analyses were negative. Staining of matrix metalloproteinase (MMP)-3 and MMP-9 was observed in and around infiltrating cells in the dermis, suggesting that MMP-3 and MMP-9 may play, in part, roles in the development of blepharochalasis, and that inhibitor of MMP may have a possibility of therapeutic application., (© 2014 Japanese Dermatological Association.)

We previously reported a case of giant basal cell carcinoma (BCC) in a 75-year-old Japanese man, who subsequently developed a pulmonary metastasis. With regard to the pathogenesis of metastasis of BCC, recently, it has been reported that high levels of expression of Twist1 and N-cadherin in primary and metastatic tumor cells, suggesting that Twist1 expression and an epithelial-mesenchymal transition (EMT) of tumor cells are important for the promotion of tumor invasion and subsequent metastasis. In this report, we identified the expressions of Twist1 in tumor cells and α-smooth muscle actin (α-SMA) in stromal cells in the primary and metastatic sites of giant BCC. These results suggest that Twist1-induced EMT of tumor cells might have been associated with distant organ metastasis in our case, and the presence of α-SMA-positive myofibroblasts surrounding a BCC nest can be one of hallmarks of the aggressiveness of BCC., (© 2013 Japanese Dermatological Association.)

Background: A novel polyomavirus, the Merkel cell polyomavirus (MCPyV) has been implicated in the pathogenesis of Merkel cell carcinoma (MCC); however, the prevalence of MCPyV in Japan has not been extensively investigated., Objective: To clarify the prevalence of MCPyV in Japanese patients with MCC., Methods: MCPyV DNA was examined by polymerase chain reaction (PCR) in formalin-fixed paraffin-embedded (FFPE) or frozen tissue samples from 26 patients with MCC diagnosed in four medical centers in Japan. Immunohistochemistry was simultaneously performed using a monoclonal antibody against the viral large T (LT) antigen. FFPE samples from basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) were also analyzed as controls., Results: Twenty-three out of 26 cases (88.5%) were positive for MCPyV DNA by PCR. The amplified products harbored 4 patterns of mutations. Phylogenetic analysis demonstrated that one of our strains was closely related to the other Japanese strains previously reported. The LT antigen was expressed in various degrees in 20 of 26 cases (76.9%) by immunohistochemistry. Histological type had little relation to CM2B4 positivity, whereas 3 of 5 trabecular-type tumors showed no staining. The immunoreactivity for CM2B4 did not correlate with the relative viral DNA load. In BCC and SCC, the LT antigen was immunohistochemically positive, but MCPyV DNA was not detected by PCR. The cells around some MCC and non-MCC tumors were stained with CM2B4 with a distribution similar to CD20- and CD45RO- (especially CD8-) positive lymphocytes., Conclusion: MCPyV was highly positive in Japanese patients with MCC. It is of note that the positive rate differs depending upon the detection method., (Copyright © 2013 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

Background: Some cases of human papillomavirus (HPV) type 56 infection in Bowen disease have been reported. However, the incidence and clinical characteristics are still unclear., Objective: To clarify the prevalence of HPV type 56-positive Bowen disease in our department and to characterize the clinical manifestations., Methods: Sixty-eight specimens of Bowen disease were examined by polymerase chain reaction using HPV consensus primers, and the amplified products were subjected to DNA sequence analyses. Moreover, positive samples were investigated by in situ hybridization. These findings were used to clarify the clinical characteristics of HPV-positive Bowen disease., Results: Eight out of 68 specimens (12%) of Bowen disease were HPV-positive, of which six specimens were HPV type 56-positive. The HPV type 56-positive lesions were characterized by a longitudinal melanonychia or a deeply pigmented keratotic lesion. The remaining two specimens were genital Bowen disease in which HPV type 16 was detected. In situ hybridization demonstrated the positive cells in the upper layer of epidermis. The HPV type 56 detected in the samples of longitudinal melanonychia can be divided into at least into two types., Conclusions: This study determined the prevalence of HPV type 56-positive Bowen disease. Longitudinal melanonychia is the most characteristic manifestation of HPV type 56-associated Bowen disease., (© 2012 The Authors. BJD © 2012 British Association of Dermatologists.)

The detection of fusion transcripts of the collagen type 1α1 (COL1A1) and platelet-derived growth factor-BB (PDGFB) genes by genetic analysis has recognized as a reliable and valuable molecular tool for the diagnosis of dermatofibrosarcoma protuberans (DFSP). To detect the COL1A1-PDGFB fusion, almost previous reports performed reverse transcription polymerase chain reaction (RT-PCR) using multiplex forward primers from COL1A1. However, it has possible technical difficulties with respect to the handling of multiple primers and reagents in the procedure. The objective of this study is to establish a rapid, easy, and efficient one-step method of PCR using only a single primer pair to detect the fusion transcripts of the COL1A1 and PDGFB in DFSP. To validate new method, we compared the results of RT-PCR in five patients of DFSP between the previous method using multiplex primers and our established one-step RT-PCR using a single primer pair. In all cases of DFSP, the COL1A1-PDGFB fusion was detected by both previous method and newly established one-step PCR. Importantly, we detected a novel COL1A1 breakpoint in exon 5. The newly developed method is valuable to rapidly identify COL1A1-PDGFB fusion transcripts in DFSP., (Copyright © 2012 Elsevier Inc. All rights reserved.)

From the viewpoint of networks, a ranking system for players or teams in sports is equivalent to a centrality measure for sports networks, whereby a directed link represents the result of a single game. Previously proposed network-based ranking systems are derived from static networks, i.e., aggregation of the results of games over time. However, the score of a player (or team) fluctuates over time. Defeating a renowned player in the peak performance is intuitively more rewarding than defeating the same player in other periods. To account for this factor, we propose a dynamic variant of such a network-based ranking system and apply it to professional men's tennis data. We derive a set of linear online update equations for the score of each player. The proposed ranking system predicts the outcome of the future games with a higher accuracy than the static counterparts.

Objective: Pericytes/pericyte precursors produce milk fat globule-associated protein with epidermal growth factor and factor VIII-like domains (MFG-E8) in vivo, and this α(v) integrin ligand enhances angiogenesis in tumors and in oxygen-induced retinopathy in mice. Inhibition of MFG-E8 production or function attenuates platelet-derived growth factor-BB (PDGF-BB)-induced migration of pericyte/pericyte precursor-like 10T1/2 cells in vitro. Herein, we describe mechanisms by which MFG-E8 modulates PDGF-BB:PDGF receptor β (PDGFRβ) signaling in 10T1/2 cells., Methods and Results: Small interfering RNA depletion of MFG-E8 from 10T1/2 cells or antibody inhibition of MFG-E8 action enhanced PDGF-BB-dependent degradation of PDGFRβ and attenuated signaling. Coimmunoprecipitation revealed transient association of MFG-E8 with PDGFRβ in PDGF-BB-treated 10T1/2 cells and reduced PDGFRβ-focal adhesion kinase association in MFG-E8-depleted cells. Confocal microscopy demonstrated that MFG-E8 binding to 10T1/2 cells was RGD motif and α(v) dependent but PDGF-BB treatment independent, whereas colocalization of MFG-E8 with PDGFRβ was enhanced by PDGF-BB. Ubiquitination of PDGFRβ was also increased in MFG-E8 small interfering RNA-transfected cells., Conclusion: Integrin α(v)-bound MFG-E8 associates with PDGFRβ and focal adhesion kinase after PDGF-BB treatment, results in cell surface retention of PDGFRβ, delays receptor degradation, potentiates downstream signaling, and enhances migration of 10T1/2 cells. MFG-E8 may promote angiogenesis, in part, via cell autonomous actions on pericytes or pericyte precursors that result in enhanced PDGF-BB:PDGFRβ signaling mediated via integrin-growth factor receptor cross-talk.

Objective: MFG-E8 (also called lactadherin and SED1) is a secreted glycoprotein that has been previously implicated in enhancement of vascular endothelial growth factor-dependent angiogenesis. Major sources of MFG-E8 in vivo and precise mechanisms of MFG-E8 action remain undetermined. The objective of this study was to identify important sources of MFG-E8 in vivo and further elucidate the role(s) of MFG-E8 in the regulation of angiogenesis., Methods and Results: We used knockout mice and anti-MFG-E8 antibodies to study MFG-E8 function in vivo. In melanomas and in retinas of mice with oxygen-induced retinopathy, MFG-E8 colocalized with pericytes rather than endothelial cells, and platelet-derived growth factor receptor β+ pericytes/pericyte precursors purified from tumors contained large amounts of MFG-E8 mRNA. Tumor- and retinopathy-associated angiogenesis was diminished in MFG-E8 knockout mice, and pericyte coverage of neovessels was reduced. Inhibition of MFG-E8 production by 10T1/2 cells (surrogate pericyte/pericyte precursors) using small interfering RNAs and short hairpin RNAs, or inhibition of MFG-E8 action with some anti-MFG-E8 antibodies, selectively attenuated migration in vitro. Significantly, the anti-MFG-E8 antibodies that inhibited 10T1/2 cell migration in vitro also inhibited pathological angiogenesis in vivo., Conclusions: These studies strongly implicate MFG-E8 in pericyte/pericyte precursor function and indicate that MFG-E8-directed therapeutics may merit further development.

Signal regulatory protein α (SIRPα) is a transmembrane protein that binds the protein tyrosine phosphatases SHP-1 and SHP-2 through its cytoplasmic region and is abundantly expressed on dendritic cells and macrophages. Wild-type (WT) C57BL/6 mice are known to be resistant to Leishmania major infection. We here found that C57BL/6 mice that express a mutant version of SIRPα lacking most of the cytoplasmic region manifested increased susceptibility to L. major infection, characterized by the marked infiltration of inflammatory cells in the infected lesions. The numbers of the parasites in footpads, draining lymph nodes and spleens were also markedly increased in the infected SIRPα mutant mice, compared with those for the infected WT mice. In addition, soluble leishmanial antigen-induced production of IFN-γ by splenocytes of the infected SIRPα mutant mice was markedly reduced. By contrast, the ability of macrophages of SIRPα mutant mice to produce nitric oxide in response to IFN-γ was almost equivalent to that of macrophages from WT mice. These results suggest that SIRPα is indispensable for protective immunity against L. major by the induction of Th1 response., (Copyright © 2010 Elsevier Inc. All rights reserved.)