Involvement of L-selectin in contact hypersensitivity responses augmented by auditory stress.

Stress affects the pathophysiology of cutaneous immune reactions, including contact hypersensitivity (CH) in individuals sensitized with sensitizing hapten, where local endothelial cell activation plays a critical role. To clarify the effects of stress in cutaneous immune reactions, we selected a CH model using annoying sound as a stress. Furthermore, we conducted the stress experiments by using selectin-deficient mice to determine the involvement of selectin molecules regarding local endothelial activation. Auditory stress augmented CH responses in the present study. Namely, ear thickness and mast cell numbers were significantly increased in stressed CH mice. mRNA expression of preprotachykinin-A, a precursor of substance-P; interferon-gamma; interleukin (IL)-4; IL-6; and tumor necrosis factor-alpha significantly increased in stressed CH mice. Furthermore, stressed L-selectin-deficient mice showed significant decreases in all parameters mentioned above relative to stressed wild-type mice in CH response. Meanwhile, treatment with anti-L-selectin Ab resulted in a significant decrease in ear thickness and mRNA levels of interferon-gamma, IL-4, IL-6, and tumor necrosis factor-alpha, but failed to significantly reduce preprotachykinin-A mRNA levels and mast cell numbers. Our results indicated that auditory stress enhances CH response and that the augmentation of this CH response might be mediated through L-selectin, but not through P- or E-selectin pathways.

Increase effect of transforming growth factor on eotaxin production by normal cultured dermal fibroblasts stimulated with interleukin-4: inhibitory effect of suplatast tosilate on eotaxin production.

Eotaxin plays a central role in the development of allergic disease, including atopic dermatitis, asthma, and nasal allergy. Interleukin (IL)-4 induces eotaxin production in normal human dermal fibroblasts. On the other hands, Transforming growth factor-beta (TGF-beta), a multifunctional regulatory cytokine, affects many biological functions, including fibroblast growth and differentiation and Th2 cytokine regulation. In this study, we investigated the effect of TGF-beta on IL-4-induced eotaxin production by normal human fibroblasts, as well as the effect of suplatast tosilate, an antiallergic drug that selectively inhibits Th2 cytokine production. Dermal fibroblast treatment with IL-4 and TGF-beta for 24 h increased eotaxin production and expression of eotaxin mRNA, as measured by enzyme-linked immunosorbent assay (ELISA) and reverse-transcriptase polymerase chain reaction (RT-PCR), respectively. TGF-beta synergistically up-regulated eotaxin production and eotaxin mRNA expression when stimulated with IL-4. Suplatast tosilate dose-dependently inhibited eotaxin production induced by IL-4 or IL-4 plus TGF-beta. These results suggest that TGF-beta may regulate skin allergic inflammation by up-regulating eotaxin production in dermal fibroblasts. Suplatast tosilate might suppress this inflammation by inhibiting eotaxin production.

Open trial of topical tacalcitol [1 alpha 24(OH)2D3] and solar irradiation for vitiligo vulgaris: upregulation of c-Kit mRNA by cultured melanocytes.

Vitiligo vulgaris is a common skin disease, however some cases show poor clinical responses to topical steroid ointment or PUVA therapy. Such regimens are generally avoided in the treatment of facial lesions or in pediatric cases because of the undesirable side effects. To confirm the excellent response to combination therapy with topical vitamin D3 ointment and solar irradiation for vitiligo achieved in the initial patients, we conducted an open trial on other patients, most of whom had poor clinical responses to the prior therapies. Fifteen patients (9 men and 6 women) with vitiligo vulgaris were enrolled in this study. Each patient was instructed to sunbathe for 30 minutes within 1 hour after topical application of the tacalcitol [1 alpha 24(OH)(2)D(3)] ointment or cream to the skin lesions every day. Six of 15 patients showed a fair and excellent clinical response to the combination therapy (more than 30% clearance of the vitiligo). The clinical effect was more apparent in patients with a history of less than 5 years of vitiligo (4 of 6 cases) in contrast to those with a history of more than 5 years (2 of 9 cases). In vitro experiments revealed that tacalcitol upregulated the expression of c-Kit mRNA by melanocytes irradiated with linear polarized infrared, UVA or short period solar irradiation. These results suggest that combination therapy with topical vitamin D(3) ointment and solar irradiation can be used as an alternate therapy for vitiligo vulgaris.

The induction of heme oxygenase-1 by exogenous nitric oxide in ex vivo normal human skin.

Gaseous carbon monoxide (CO) has received attention as a neurotransmitter and as a material involved in persistent dilatation of vessels. CO is released by heme oxygenase (HO) during the process from heme to bilirubin or biliverdin. Many reports have revealed that exogenous nitric oxide (NO) can induce HO-1 in vitro, which is the induced isoform of HO. In the present study, we attempted an ex vivo system as an explant culture. A quantitative analysis was performed in combination with a reverse transcription-competitive polymerase chain reaction method, which proved to be very accurate, as well as a qualitative analysis with an immunohistochemistry. With this system we confirmed the induction of HO-1 mRNA and protein by exogenous NO in normal human skin. Our results concluded that this ex vivo system was very useful, because skin samples could be handled easily under conditions close to the in vivo situation.

The roles of P- and E-selectins and P-selectin glycoprotein ligand-1 in primary and metastatic mouse melanomas.

BACKGROUND: Malignant melanoma is often accompanied by a host response of inflammatory cell infiltration that is highly regulated by multiple adhesion molecules. OBJECTIVE: To evaluate the role of adhesion molecules, including P-selectin glycoprotein ligand-1 (PSGL-1), P-selectin, and E-selectin. METHODS: Subcutaneous primary growth and metastasis to the lung of B16 melanoma cells were examined in mice lacking PSGL-1, P-selectin, or E-selectin. RESULTS: Primary subcutaneous growth of B16 melanoma was augmented by loss of PSGL-1, P-selectin, or E-selectin, while pulmonary metastasis was reduced by the loss of E-selectin. The enhancement of subcutaneous tumor growth was associated with a reduced accumulation of natural killer cells, CD4(+) T cells and CD8(+) T cells, while the attenuation of pulmonary metastasis was related to the numbers of CD8(+) T cells. The expressions of transforming growth factor (TGF)-ß and interleukin (IL)-6 were correlated with primary subcutaneous growth; TGF-ß, IL-6, and interferon-γ were related to number of metastatic lung nodules. Cytotoxicity against melanoma cells in splenocytes and in tumor-draining lymph node cells were not defective by the absence of adhesion molecules, suggesting that the enhancement of tumor growth and metastasis caused by the loss of selectins results from an impaired migration of effector cells into the tissue. CONCLUSIONS: The results indicate the complexity of anti-tumor responses mediated by adhesion molecules in primary subcutaneous tumors and pulmonary metastasis of murine experimental melanoma.

Topical glucocorticoid augments scratching behaviour in dinitrofluorobenzene-sensitized mice by the induction of substance P.

Topical glucocorticoid (GC) is commonly applied in atopic dermatitis treatment. However, the chronic use of GC may be associated with significant side effects. In this study, we investigated whether long-term epicutaneous application of GC modulates scratching behaviour in dinitrofluorobenzene (DNFB) contact-sensitized mice. After challenge with DNFB, scratching behaviour was increased in DNFB-sensitized mice treated with GC in contrast to control mice. In addition, reverse transcriptase-polymerase chain reaction analysis demonstrated that the expression of preprotachykinin-A (PPT-A) mRNA, a precursor of substance P (SP), and inducible nitric oxide synthase (iNOS) mRNA in mice, to which GC was applied, was only observed. In order to evaluate the factors responsible for the augmented scratching behaviour, we injected various cytokines (interleukin-1alpha (IL-1alpha), IL-2, IL-3 and tumour necrosis factor-alpha (TNF-alpha)) subcutaneously into the ear of DNFB contact-sensitized mice before DNFB challenge. Among the cytokines, only IL-3 and TNF-alpha significantly increased scratching behaviour in DNFB contact dermatitis mice. Furthermore, PPT-A mRNA was only expressed in mice pre-injected with IL-3 before challenge, but not in those pre-injected with other cytokines. Taken together, our results suggest that topical GC may augment the itching sensation in DNFB-sensitized mice through modulation of iNOS and SP induced by IL-3.

Substance P induced preprotachykinin-a mRNA, neutral endopeptidase mRNA and substance P in cultured normal fibroblasts.

In certain skin diseases, stress can modulate the induction and/or progression of cutaneous manifestations. However, little is known about the circuit in neuroendocrine and in the immune systems of the skin. To address this question, we have analyzed the regulatory mechanisms of autocrine induction of substance P (SP) by cultured normal human fibroblasts that compose the major population of the skin and might augment stress-induced skin inflammatory responses. In nonstimulated conditions, normal fibroblasts express a moderate amount of preprotachykinin-A (PPT-A), a precursor of SP mRNA, and exogenous SP significantly upregulated PPT-A mRNA expression. Maximum response of SP peptide and SP mRNA in fibroblasts was observed 1-3 h after stimulation with SP. In contrast, the expression of neutral endopeptidase (NEP), a cell surface peptide with hydrolyzing activity of SP, was increased in fibroblasts stimulated with SP after 24 h. The administration of NEP inhibitor (phosphoramidon) to the fibroblasts induced higher SP production. In addition, the neurokinin (NK) receptor antagonists (spantide, FK224 and FK888) and protein synthesis inhibitor (cycloheximide) inhibited SP production by 30-40% of control response. In immunostaining study, specific cytoplasmic staining of SP was observed in fibroblasts stimulated with SP. Finally, we confirmed that the nucleotide sequence of the PPT-A expressed in fibroblasts perfectly corresponded to the gene bank human PPT-A cDNA. This is the first report that SP mRNA, NEP mRNA and SP peptide can be induced by normal human skin fibroblasts in response to exogenous SP, and that fibroblast-derived SP might play an important role in the induction and acceleration of certain cutaneous diseases.

The role of RANTES in a murine model of food allergy.

Food allergy is an important and common health issue, and there is a need to identify and characterize the sensitizing mechanisms. One of the common causes of food allergy is ovalbumin (OVA), a dietary antigen from eggs. We hypothesized that OVA-induced food allergy in the gut involves the activation of the chemokine regulated on activation, normal T cell expressed and secreted (RANTES), which then recruits eosinophils to lesioned tissue. The purpose of this study was to clarify whether RANTES expression correlates with eosinophil infiltration in the gut of OVA-sensitized BALB/c mice in response to oral OVA challenge. BALB/c mice were immunized with OVA 1 microg and sensitized after 2 weeks by intragastric administration of OVA. Sensitization to the oral OVA challenge was analyzed by examining eosinophil infiltration into the gut tissue (immunohistochemistry), mucosal eosinophil cationic protein (ECP) concentration, and RANTES mRNA expression (reverse-transcriptase polymerase chain reaction and Southern blotting) at 3, 6, 12, and 24 h after the challenge. There was marked edema of the intestinal villi, and eosinophil infiltration to the lamina propria peaked at 6 h in OVA-sensitized mice. RANTES mRNA expression peaked at 3 h and 6 h and declined thereafter. The expression of RANTES mRNA in the allergic mice was much higher than in the nonallergic, normal, or unsensitized control mice. Tissue eosinophilia and intestinal ECP levels were significantly correlated with the RANTES mRNA level. We conclude that RANTES may play a central role in the pathogenesis of food-mediated gastrointestinal allergy.