Hirokazu Watanabe

Toxic Epidermal Necrolysis and Stevens-Johnson Syndrome Are Induced by Soluble Fas Ligand

The pathogeneses of toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS), both severe blistering diseases usually associated with drug intake, are not fully elucidated. Histologically, both TEN and SJS are characterized by extensive keratinocyte apoptosis. Previous studies have shown that keratinocyte apoptosis in TEN and SJS was induced by a suicidal interaction between Fas and Fas ligand (FasL), which are both expressed by keratinocytes. However, our preliminary examinations demonstrated that FasL is hardly detected on keratinocytes. We hypothesized that soluble FasL (sFasL) is secreted by peripheral blood mononuclear cells (PBMCs), and this interacts with the Fas expressed on keratinocytes in TEN and SJS. To justify this hypothesis, we investigated whether sFasL secreted by PBMCs could induce the keratinocyte apoptosis in TEN and SJS. Enzyme-linked immunosorbent assay analysis demonstrated that there was no significant sFasL increase in any samples of healthy controls (<40 pg/ml, n = 14) and patients with an ordinary erythema multiforme-type drug eruption (41.5 +/- 3.1 pg/ml, n = 14), whereas high concentrations are detected in all samples of TEN and SJS patients (TEN: 131.5 +/- 57.4 pg/ml, n = 8; SJS: 119.1 +/- 41.0 pg/ml, n = 14) (P < 0.0001). In vitro analysis using cultured keratinocytes revealed that the sera of TEN and SJS patients induced abundant keratinocyte apoptosis compared to erythema multiforme-type drug eruption sera. Furthermore, on stimulation with the causal drug, PBMCs obtained from TEN and SJS patients secreted high levels of sFasL. Taken together, these results indicate that sFasL secreted by PBMCs, not keratinocytes, plays a crucial role in the apoptosis and pathomechanism of TEN and SJS, and that the serum sFasL level may be a good indicator for the early diagnosis of TEN and SJS.

Overexpression of Pigment Epithelium-Derived Factor Decreases Angiogenesis and Inhibits the Growth of Human Malignant Melanoma Cells in Vivo

Pigment epithelium-derived factor (PEDF) has recently been shown to be the most potent inhibitor of angiogenesis in the mammalian eye, and is involved in the pathogenesis of angiogenic eye disease such as proliferative diabetic retinopathy. However, a functional role for PEDF in tumor growth and angiogenesis remains to be determined. In this study, we have investigated both the in vitro and in vivo growth characteristics of human malignant melanoma G361 cell lines, stably transfected to overexpress human PEDF. Expression levels of PEDF proteins in melanoma cell lines G361 and A375 were comparable with that of human cultured melanocytes, whereas vascular endothelial growth factor levels in two tumor cell lines were much stronger than that in normal melanocytes. Overexpression of PEDF was found to significantly inhibit tumor growth and vessel formation in G361 nude mice xenografts. Furthermore, in vitro proliferation rates of G361 cells were decreased in PEDF-transfected cells. PEDF proteins showed dose-dependent induced growth retardation and apoptotic cell death in nontransfected G361 cells, which were completely prevented by treatment with antibodies against the Fas ligand. Our present study highlights two beneficial effects of PEDF treatment on melanoma growth and expansion; one is the suppression of tumor angiogenesis, and the other is induction of Fas ligand-dependent apoptosis in tumor cells. PEDF therefore might be a promising novel therapeutic agent for treatment of patients with melanoma.

Ultraviolet A-induced production of matrix metalloproteinase-1 is mediated by macrophage migration inhibitory factor (MIF) in human dermal fibroblasts.

Matrix metalloproteinases (MMPs) are thought to be responsible for dermal photoaging in human skin. In the present study, we evaluated the involvement of macrophage migration inhibitory factor (MIF) in MMP-1 expression under ultraviolet A (UVA) irradiation in cultured human dermal fibroblasts. UVA (20 J/cm2) up-regulates MIF production, and UVA-induced MMP-1 mRNA production is inhibited by an anti-MIF antibody. MIF (100 ng/ml) was shown to induce MMP-1 in cultured human dermal fibroblasts. We found that MIF (100 ng/ml) enhanced MMP-1 activity in cultured fibroblasts assessed by zymography. Moreover, we observed that fibroblasts obtained from MIF-deficient mice were much less sensitive to UVA regarding MMP-13 expression than those from wild-type BALB/c mice. Furthermore, after UVA irradiation (10 J/cm2), dermal fibroblasts of MIF-deficient mice produced significantly decreased levels of MMP-13 compared with fibroblasts of wild-type mice. Next we investigated the signal transduction pathway of MIF. The up-regulation of MMP-1 mRNA by MIF stimulation was found to be inhibited by a PKC inhibitor (GF109203X), a Src-family tyrosine kinase inhibitor (herbimycin A), a tyrosine kinase inhibitor (genistein), a PKA inhibitor (H89), a MEK inhibitor (PD98089), and a JNK inhibitor (SP600125). In contrast, the p38 inhibitor (SB203580) was found to have little effect on expression of MMP-1 mRNA. We found that PKC-pan, PKCα/βII, PKCδ (Thr505), PKCδ (Ser643), Raf, and MAPK were phosphorylated by MIF. Moreover, we demonstrated that phosphorylation of PKCα/βII and MAPK in response to MIF was suppressed by genistein, and herbimycin A as well as by transfection of the plasmid of C-terminal Src kinase. The DNA binding activity of AP-1 was significantly up-regulated 2 h after MIF stimulation. Taken together, these results suggest that MIF is involved in the up-regulation of UVA-induced MMP-1 in dermal fibroblasts through PKC-, PKA-, Src family tyrosine kinase-, MAPK-, c-Jun-, and AP-1-dependent pathways.

Tissue Regeneration Using Macrophage Migration Inhibitory Factor-Impregnated Gelatin Microbeads in Cutaneous Wounds

Migration inhibitory factor (MIF) responds to tissue damage and regulates inflammatory and immunological processes. To elucidate the function of MIF in cutaneous wound healing, we analyzed MIF knockout (KO) mice. After the excision of wounds from the dorsal skin of MIF KO and wild-type (WT) mice, healing was significantly delayed in MIF KO mice compared to WT mice. Lipopolysaccharide treatment significantly increased [(3)H]thymidine uptake in WT mouse fibroblasts compared to MIF KO mouse fibroblasts. Furthermore, there was a significant reduction in fibroblast and keratinocyte migration observed in MIF KO mice after 1-oleoyl-2-lysophosphatidic acid treatment. We subsequently examined whether MIF-impregnated gelatin slow-release microbeads could accelerate skin wound healing. Injection of more than 1.5 microg/500 microl of MIF-impregnated gelatin microbeads around a wound edge accelerated wound healing compared to a single MIF injection without the use of microbeads. MIF-impregnated gelatin microbeads also accelerated skin wound healing in C57BL/6 mice and diabetic db/db mice. Furthermore, incorporating MIF-impregnated gelatin microbeads into an artificial dermis implanted into MIF KO mice accelerated procollagen production and capillary formation. These findings suggest that MIF is crucial in accelerating cutaneous wound healing and that MIF-impregnated gelatin microbeads represent a promising treatment to facilitate skin wound healing.

Impaired contact hypersensitivity in macrophage migration inhibitory factor‐deficient mice

To determine whether macrophage migration inhibitory factor (MIF) is required for contact hypersensitivity (CHS) response, MIF‐deficient (MIF KO) and wild‐type (WT) mice were sensitized with trinitrochlorobenzene (TNCB) or oxazolone on their abdominal skin and challenged on the dorsum skin of one ear 5 days later. Significant ear swelling was observed in the WT mice, but this response was inhibited in the MIF KO mice (p<0.01 for MIF KO vs. WT mice in 24 h). In addition, lymph node cells from hapten‐sensitized MIF KO mice showed a decreased capacity for transferring the CHS response. A topical application of TNCB (200 μg) caused a significant decline in epidermal Langerhans cell (LC) density (20.3%; p<0.01 compared with vehicle) 4 h after application in WT mice, but it failed to provoke a significant epidermal LC migration in MIF KO mice (7.4%). By mixed lymphocyte reaction, the T cell proliferative response to alloantigen was significantly decreased in the MIF KO mice compared with WT mice (p<0.005). Taken together, these results indicate that MIF is pivotal in the regulation of cutaneous immune responses and plays a central role in LC migration and T cell proliferation for the CHS response.

Promoter region polymorphism of macrophage migration inhibitory factor is strong risk factor for young onset of extensive alopecia areata

We have demonstrated that serum macrophage migration inhibitory factor (MIF) was significantly elevated in patients with extensive alopecia areata (AA). Recently, functional polymorphisms have been identified in the MIF promoter region. To address the functional and prognostic relevance of the −173G/C and −794[CATT]5–8 repeat polymorphisms in MIF genes in patients with extensive AA, 113 patients with extensive AA and 194 healthy controls were genotyped. We found that MIF−173*C was a risk factor for early onset (<20 years) of extensive AA (odds ratio for GC heterozygotes with −173G/C was 4.88 (95% CI, 2.04–11.8), P=0.00038; odds ratio for CC homozygotes with −173G/C was 10.42 (95% CI, 2.56–43.5), P=0.0011). We found no statistically significant differences in the genotype frequencies of the −794[CATT]5–8 repeat polymorphism and extensive AA. These results suggest that polymorphisms within the MIF−173*C allele confer an increased risk of susceptibility to the extensive forms of AA, especially with an early onset of disease. MIF is therefore suggested to be closely implicated in the pathogenesis of the more extensive forms of AA.

Desmoplastic fibroblastoma (collagenous fibroma)

Desmoplastic fibroblastoma (DF) is a rare fibrotic tumor that has a wide anatomic distribution and it can appear in deep sections of the subcutis, in fascia, in aponeurosis or in skeletal muscles. This report describes a case of DF that appeared on the left side of the neck of a 55‐year‐old male as a 3.5‐cm solitary, firm nodule. Histologically, it was composed of stellate or bland spindle‐shaped cells embedded in a loose collagenous stroma. The entrapment of fat and muscle tissues was focally identified at the edges of the tumor. The stellate and multinucleated cells in the lesion were strongly positive for vimentin but negative for cytokeratin, smooth muscle actin, desmin, S‐100, CD34, factor XIIIa, and CD68. These findings suggest that the stellate and multinucleated cells in the lesion were of fibroblastic origin and this neoplasm was pathologically benign.

A case of giant vascular eccrine spiradenoma with unusual clinical features

Giant vascular eccrine spiradenoma (GVES) is a rare, highly vascular variant of eccrine spiradenoma (ES). To our knowledge, only five such cases have been previously reported in the literature. We report a Japanese patient with GVES on his right shoulder. A 76-year-old Japanese man presented with a tumour involving his right shoulder, which had been present for about 3 years and had gradually increased in size. On physical examination, a pale red pedunculated tumour measuring 50 · 34 · 26 mm was seen, which had erosive lesion on the surface (Fig. 1a). The patient had no pain and reported no other symptoms except bleeding from the lesion. There was no regional lymph-node involvement. The blood test results were almost within normal limits. Enhanced computed tomography showed some high-density nodules in the peripheral region of the tumour (Fig. 1b); in contrast, the central region of the tumour was low density and was not enhanced. The patient underwent total excision of the lesion. Histological examination of the excised tumour showed a prominent blood-filled vascular space and clearly delimited cords (Fig. 2a), showing two types of cell: cells with large pale nuclei in the centre and basaloid cells with small, dark nuclei at the periphery (Fig. 2b). Dilated vascular spaces containing red blood cells were present in the stroma. Immunohistochemically, the luminal large, pale epithelial cells were strongly positive for cytokeratin 19, carcinoembryonic antigen and epithelial membrane antigen, and the outer layer of small basaloid cells was negative. In addition, the cells lining the vascular space were positive for vimentin, CD31 and CD34. Mindbomb homologue (MIB)-1, an antibody against Ki67, was expressed on 3% of the tumour cells. These histological findings were diagnostic of GVES. ES is a benign, adnexal tumour originating from the eccrine sweat glands. It occurs commonly as a subcutaneous solitary nodule, or rarely as multiple lesions. The tumour usually measures < 10 to > 50 mm in diameter. Most of the lesions follow a benign clinical course, and gradually increase in size. In addition, malignant degeneration may also rarely occur. GVES is a rare variant of ES and was first described by Cotton et al. in 1986. Only five such cases have been previously reported in the literature. According to those reports, the lesions were dome-shaped tumours, measuring 20–50 mm in size with a marked degree of vascularity. However, our case was a unique pedunculated tumour, and the clinical features were different (a)

Histochemical analysis of macrophage migration inhibitory factor in psoriasis vulgaris

Abstract. Psoriasis is a persistent cutaneous disease characterized by skin inflammation and infiltration of immunocytes such as lymphocytes and monocytes/macrophages, concomitant with abnormal epidermal hyperproliferation. We previously showed that the serum level of macrophage migration inhibitory factor (MIF) and its production by peripheral blood mononuclear cells of patients with psoriasis were closely correlated with the severity of clinical symptoms; however, the precise role of MIF in psoriatic epidermis remains to be clarified. The current study was carried out to elucidate the possible involvement of MIF in psoriasis, using immunohistochemistry and in situ hybridization. In contrast to elevated serum MIF in psoriasis, MIF-positive staining in the lesional psoriatic epidermis was significantly decreased, as demonstrated by immunohistochemical analysis using an anti-MIF antibody. Consistent with this finding, we found, by in situ hybridization, that MIF mRNA concomitantly decreased in the psoriatic lesions. Although the reason for the different MIF levels in the psoriatic epidermis and in the circulation remains unknown, it is hypothesized that MIF, a potential growth factor, might be decreased in psoriatic lesions to counterregulate the abnormal epidermal proliferation caused by dysregulation of cytokines and growth factors.

Expression of macrophage migration inhibitory factor in rat skin during embryonic development

Abstract:  We have previously shown that human epidermal keratinocytes express macrophage migration inhibitory factor (MIF) mRNA, and immunohistochemical studies showed that MIF is expressed in human epidermis. To explore the possible pathophysiological roles of MIF in skin during rat fetal development, we examined the expression patterns of MIF during rat epidermal development using Northern blot analysis and in situ hybridization. Expression of MIF mRNA was first detected by in situ hybridization in the developing epidermis and hair germ cells from embryonic day (ED) 16. From ED 19, moderate levels of MIF expression were detected in the epidermis and epithelial sheath cells of growing hair follicles. In postnatal rat skin, higher MIF expression was detected in the epidermis and hair follicles on postnatal day 3. These observations were also confirmed by Northern blot analysis. Immunohistochemical analysis with an anti‐MIF antibody showed a similar distribution to that of the mRNA. Our results suggest that MIF is associated with epidermal and hair follicle development.