小宮根 真弓

Background: Kindler syndrome (KS) is a rare, inherited skin disease characterized by blister formation and generalized poikiloderma. Mutations in KIND1, which encodes kindlin-1, are responsible for KS. c.1089del/1089+1del is a recurrent splice-site deletion mutation in KS patients. Objective: To elucidate the effects of c.1089del/1089+1del at the mRNA and protein level. Methods: Two KS patients with c.1089del/1089+1del were included in this study. Immunofluorescence analysis of KS skin samples using antibodies against the dermo-epidermal junction proteins was performed. Exon-trapping experiments were performed to isolate the mRNA sequences transcribed from genomic DNA harbouring c.1089del/1089+1del. beta 1 integrin activation in HeLa cells transfected with truncated KIND1 cDNA was analyzed. Results: Immunofluorescence study showed positive expression of kindlin-1 in KS skin with c.1089del/1089+1del mutation. We identified the exon-8-skipped in-frame transcript as the main product among multiple splicing variants derived from that mutation. HeLa cells transfected with KIND1 cDNA without exon 8 showed impaired beta 1 integrin activation. Exon-8-coding amino acids are located in the FERM F2 domain, which is conserved among species, and the unstructured region between F2 and the pleckstrin homology domain. Conclusion: This study suggests that exon-8-skipped truncated kindlin-1 is functionally defective and does not compensate for the defects of KS, even though kindlin-1 expression in skin is positive. (c) 2010 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

31歳男。陰茎腹側の縫線上に径5mmの表面平滑、白色調で弾性軟の結節を認めた。病理組織学的所見で真皮内に単房性嚢腫を認め、その壁は1〜数層、主として立方ないし円柱上皮で構成されていた。免疫組織化学的所見でCarcinoembryonic antigenは嚢腫壁の内腔側に顆粒状の陽性像を示し、S-100、アクチンはともに陰性で、種々の抗サイトケラチン抗体を用いた免疫染色ではK8、18は嚢腫壁の最内側に陽性、K7、19は壁の全層にわたって陽性像を示した。局所麻酔下に切除縫縮し、術後20ヵ月の現在、再発はない。

Dendritic cells (DCs) are a group of professional antigen-presenting cells, and many genes are known to be associated with their maturation. We compared the transcriptional profiles of immature and mature mouse Langerhans cells using the suppressive, subtractive hybridization method and identified a novel gene of unknown function, termed herein transmembrane protein 123 (Tmem123), of which mRNA expression was enhanced in mature but not in immature Langerhans cells. Its expression was also enhanced in other mature DCs such as bone marrow-derived DCs (BMDCs) and splenic DCs. Interestingly, CD40 expression was up-regulated on mature BMDCs cultured with colchicine concurrently with the enhanced expression of Tmem123 compared with that of fresh BMDCs. Furthermore, the expression of CD40 was enhanced on Tmem123-transfected DC2.4 cells, a mouse BMDC-derived cell line, compared with that on mock-transfected DC2.4 cells. This enhancement of CD40 expression did not occur after deletion of lysosome/endosome targeting YXX phi motifs (where X is any amino acid and phi is a bulky hydrophobic amino acid) in the Tmem123 cytoplasmic tail. By stimulation with anti-CD40 monoclonal antibody, these transfectants secreted an increased amount of IL-12/23 p40 compared with mock-transfected DC2.4 cells. Thus, our study demonstrates that Tmem123 may be used as a new maturation marker in DCs and that this molecule may be closely associated with the cell surface expression of CD40.

IL-1 is a proinflammatory cytokine consisting of two molecular species, IL-1 alpha and IL-1 beta, and IL-1R antagonist ( gene: Il1rn) is the endogenous suppressor. Il1rn(-/-) mice spontaneously develop autoimmune diseases, such as arthritis and aortitis, and a dermatitis that histologically resembles human psoriasis. The pathogenic mechanisms underlying this dermatitis, however, remain to be elucidated. In this study, we demonstrated that the production of inflammatory cytokines and chemokines was enhanced at the site of inflammation. The development of dermatitis was completely suppressed in Tnfsf1a(-/-) but not in Il6(-/-) mice, similar to that observed in arthritis and aortitis. However, IL-17 deficiency did not affect the development of dermatitis at all, in clear contrast to that of arthritis and aortitis. Different from arthritis and aortitis, adoptive transfer of Il1rn(-/-) T cells did not induce dermatitis in the recipient SCID mice and skin lesions developed in Il1rn(-/-) SCID mice, indicating that T cells are not involved in the development of skin lesions. In support for this, bone marrow cell transplantation experiments showed that TNF produced by skin residential cells, but not bone marrow cell-derived cells, was important for the development of dermatitis. Furthermore, we showed that IL-1 directly enhanced TNF and chemokine expression in keratinocytes. These observations suggest that excess IL-1 signaling directly activates keratinocytes to produce TNF and chemokines, resulting in the development of psoriasis-like skin lesions without the involvement of autoimmunity in Il1rn(-/-) mice. The Journal of Immunology, 2010, 185: 1887-1893.

72歳,女性.15年前から徐々に増大する前頭部の皮下結節を主訴に当科を受診した.初診時,35×35×20mmの皮表はやや紅色調で外方に突出した弾性硬の腫瘤を認めた.病理組織学的には,外毛根鞘性角化を呈し,線維性被膜に囲まれた多房性の嚢腫様構造を認め,増殖性外毛根鞘性腫瘍と診断した.PCNAおよびKi-67染色では,両者とも腫瘍胞巣の最も外側で陽性細胞を認めた.抗サイトケラチン抗体染色でK8,K19はともに腫瘍壁に陰性であったが,K16,K17は外毛根鞘性角化を呈する部分に陽性であった.これらより腫瘍の増殖活性と角化傾向の特徴を示唆する所見と考えた.(著者抄録)

Atopic dermatitis frequently accompanies bronchial asthma, allergic rhinitis, and allergic conjunctivitis, the pathogenesis of which has frequently focused on the immunological aspects; however, skin eruption in atopic dermatitis occurs mainly in the epidermis, whose barrier function and cytokine expression have been revealed to be abnormal. In addition, the epidermis contains Langerhans cells, antigen-presenting cells, which could be considered the sentinel of the immune system. Some atopic dermatitis patients have been revealed to have mutations or SNPs (single-nucleotide polymorphisms) in the filaggrin gene, which affect the epidermal barrier function. Proteinases in the epidermis are of importance in maintaining the epidermal barrier, abnormalities of which have been reported in atopic dermatitis. Abnormalities of various cytokines and chemokines produced by keratinocytes have also been reported. Thymic stromal lymphopoietin (TSLP) produced by keratinocytes has recently been a focus in atopic dermatitis. Adrenergic/cholinergic responses in the epidermis could also influence the pathogenesis of atopic dermatitis. Considering epidermal keratinocytes as a trigger of immune abnormalities, not only as a peripheral effector, would be important to further disclose the pathogenesis of this enigmatic disorder.

Background: Anti-cyclic citrullinated peptide antibodies (anti-CCP) are reported to be found in 5-13% of patients with psoriatic arthritis (PsA). However, whether anti-CCP-positive PsA patients and rheumatoid arthritis (RA) patients have a similar pathophysiological background still remains uncertain. Objective: To determine the prevalence of anti-CCP antibodies in patients with PsA and characterize these anti-CCP-positive patients of PsA. Methods: We measured the serum levels of the anti-CCP antibodies in patients with PsA (n = 16), psoriasis (n = 15), RA (n = 9) and healthy controls (n = 11). Serum levels of rheumatoid factor (RF), matrix metalloproteinase-3 (MMP-3), cartilage oligomeric matrix protein (COMP), interleukin (IL)-23p19 and IL-12p40 were also measured in all the samples. Results: Two of the 16 PsA patients (13%) were positive for anti-CCP antibodies with high titers of RF. However, the serum IL-23p19 levels were two orders of magnitude higher in the anti-CCP-positive PsA patients as compared with those in the RA patients and anti-CCP-negative PsA patients. No significant elevation of the serum levels of MMP-3, COMP and IL-12p40 was found in these patients. Conclusion: Thirteen percent of the PsA patients were positive for anti-CCP. These patients do not fulfill the American College of Rheumatology (ACR) classification criteria for RA so far. Furthermore, they showed the typical clinical features of PsA rather than those of RA. Although anti-CCP-positive PsA patients may possibly be have a risk of developing RA, we propose that these patients be classified, for the moment, into a independent subtype of PsA, as a different entity from RA. (c) 2008 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

顆粒変性を来たす代表的な疾患である水疱型先天性魚鱗癬様紅皮症(BCIE)，およびVörner型掌蹠角化症(PPK)の浸潤細胞を検討した結果多数のマスト細胞を認めた。マスト細胞の走化因子であるbasic fibroblast growth factor(basic FGF)の発現を検討した結果，健常人皮膚では有棘層上層に強く発現しているのに対し，これらの疾患では基底層に発現を認めた。basic FGFは，血管および表皮細胞増殖促進作用も報告がある。これらの疾患患者で認められる著明な過角化を伴う表皮増殖，毛細血管の増生，マスト細胞浸潤は，basic FGFが誘導因子の一つである可能性が示唆された。

Background. Ultraviolet (UV) B radiation from sunlight can result in tanning or burning of the skin. Narrowband UVB (NB-UVB), a relatively new light source that is not yet widely available, is effective for treating generalized psoriasis without the use of psoralens. Aims. The melanin-related metabolite 5-S-cysteinyldopa (5-S-CD), which reflects pheomelanin production, has been used as a biological marker of melanoma progression, but there are no studies available on therapeutic UVB effects on serum 5-S-CD of human subjects. In the present study, we measured the time course of changes in serum levels of 5-S-CD in patients with psoriasis undergoing NB-UVB phototherapy. Methods. In total, 11 Japanese patients with generalized psoriasis vulgaris received NB-UVB treatment five times per week, at an initial dose of 0.1 J/cm2. The dose was increased by 10-20% per treatment for &gt 20 treatments. Serum samples were taken before and 3, 7, 10, 14 and 28 days after phototherapy. Results. After 4 weeks of NB-UVB treatment, 9 of 11 patients were in remission, confirming the effectiveness of NB-UVB for treating Japanese patients with psoriasis. Two patients withdrew before day 28 because of other complications. Mean level of 5-S-CD in serum was significantly increased on day 7, 10 14 and 28 compared with the level before phototherapy and it peaked on day 10. Conclusions. Serum 5-S-CD levels were significantly increased by therapeutic UVB exposure. Sustained levels of 5-S-CD in serum appear to reflect the degree of skin injury during NB-UVB phototherapy. © 2008 The Author(s).

A 46-year-old man had a cystic mass on the right side of his scalp. Histological examination revealed a cystic dermal nodule composed of relatively circumscribed lobules of proliferating squamous epithelium, with atypical mitoses and dyskeratotic cells of invasive structure, which was diagnosed as proliferating tricholemmal cystic carcinoma (PTCC). Most of the cyst was composed of thick layers of highly proliferating, atypical, dedifferentiated epithelium (dedifferentiated part), which was attached to a highly proliferative but mildly differentiated part. A completely differentiated, tricholemmal cyst (TC)-like part was also attached to the main cyst, which supports the idea of PTCC beginning in a pre-existing TC. The dedifferentiated and mildly differentiated parts exhibited a high frequency of proliferating cell nuclear antigen (PCNA)-positive cells both in the basal and the suprabasal layers, while PCNA staining was almost negative in the TC-like part. Expression of cytokeratin (CK)10 and CK16 suggested disturbed epidermal differentiation in dedifferentiated part, while TC-like part showed well-differentiated trichilemmal epithelium and the mildly differentiated part was in the middle of these two.

CC chemokine ligand (CCL)17 and CCL27 produced by epidermal keratinocytes (KCs) recruit CC chemokine receptor (CCR)4 and CCR10 expressing T cells into the skin, respectively, resulting in enhanced skin inflammation. However, CCR4/CCL17 and CCR10/CCL27 interactions in epidermal KCs have not been investigated. The purpose of this study was to evaluate the role of the CCR4/CCL17 and CCR10/CCL27 loops in cutaneous immune reaction. Normal human KCs (NHKS) and HaCaT KCs expressed both CCR4 and CCR10 at mRNA and Protein levels. CCR4 ligand CCL17 but not CCR10 ligand CCL27 induced production of IL-12 p40, granulocyte/monocyte colony-stimulating factor (GM-CSF) and nerve growth factor (NGF) by KCs. Both CCL17 and CCL27 induced migration of KCs in Boyden chamber assay and wound scratch assay. This study revealed that CCR4 and CCR10 are expressed on epidermal KCs and that both are functional in terms of skin cytokine production and/or migration to their ligand CCL17 and CCL27, respectively. Thus this study provided new insight into chemokine/chemokine receptors of KCs. (C) 2008 Elsevier Ltd. All rights reserved

Dyschromatosis symmetrica hereditaria (DSH), is a pigmentary genodermatosis of autosomal dominant inheritance. Since we clarified that the disease is caused by a mutation of the adenosine deaminase acting on the RNA 1 gene (ADAR1) in 2003, the molecular pathogenesis of a peculiar clinical feature of the disease has been expected to be clarified. We examined five familial cases and one sporadic case of Japanese families with DSH. The mutation analyses were done with single-strand conformation polymorphism/heteroduplex (SSCP/HD) analysis and direct sequencing of ADAR1. The DNA analysis of each patient revealed one missense mutation (p.F1091S), two nonsense mutations (p.C893X, p.S581X) and three frame-shift mutations (p.E498fsX517, p.F1091fsX1092, p.L855fsX856). Visual and electron microscopic findings showed abundant melanin pigment deposited all over the basal layer, and enlarged melanocytes with long dendrites located in the pigmented lesions with small or immature melanosomes scattered sparsely in the cytoplasm, but in the adjacent keratinocytes many small melanosomes were singly dispersed or aggregated. The hypopigmented areas showed little melanin deposition and reduced numbers of melanocytes in which much degenerative cytoplasmic vacuole formation could be observed by electron microscopy. Herein, we report six cases of DSH with six novel mutations. The variety of their clinical phenotypes even in the pedigree may suggest the presence of factors other than the ADAR1 gene influencing the extent of the clinical skin lesion. Microscopic findings suggest that the clinical appearance must have developed directly by melanocyte variations mainly induced by the ADAR1 gene mutations.

CCL27 is one of the CC chemokines produced by epidermal keratinocytes and is suggested to be involved in the pathogenesis of inflammatory skin diseases. To clarify the contribution of CCL27 in skin inflammation, we created transgenic C57BL/6 mice that constitutively produce CCL27 in epidermal keratinocytes. These mice had high serum CCL27 levels and did not show any phenotypical change. Thus we stimulated these mice with various reagents by single and repeated application. Interestingly, only contact hypersensitivity to repeated application with fluorescein isothiocyanate was significantly enhanced in transgenic mice compared to non-transgenic mice. Under this condition, the numbers of inflammatory cells, CCR10-positive cells, CCR4-positive cells and cutaneous lymphocyte-associated antigen-positive cells were increased, and IL-4 mRNA expression was higher in the lesional skin of transgenic mice. Increased number of mast cells and higher serum IgE levels, which were similar to atopic dermatitis, were also observed. These results indicated that CCL27 modified inflammation by attracting CCR10-positive and CCR4-positive cells into the lesional skin, and may participate in the pathogenesis of Th2-shifted skin diseases such as atopic dermatitis.

The control of the stem cell compartment in epidermis is closely linked to the regulation of keratinocyte proliferation and differentiation. beta 1 integrins are expressed 2-fold higher by stem cells than transit-amplifying cells. Signaling from these beta 1 integrins is critical for the regulation of the epidermal stem cell compartment. To clarify the functional relevance of this differential expression of beta 1 integrins, we established HaCaT cells with high beta 1integrin expression by repeated flow cytometric sorting of this population from the parental cell line. In these obtained cells expressing beta 1 integrins by 5-fold, MAPK activation was markedly increased. Regarding the upstream of MAPK, Gab I phosphorylation was also higher with high beta 1 integrin expression, while She phosphorylation was not altered. In addition, enhanced phosphatidylinositol 3-kinase activation was also observed. These observations suggest that Gab1 and phosphatidylinositol 3-kinase play pivotal roles in the beta 1 integrin-mediated regulation of the epidermal stem cell compartment. (C) 2007 Elsevier Inc. All rights reserved.

Early inflammatory changes in psoriatic plaques were investigated immunohistochemically by studying the normal-appearing skin adjacent to the plaques (perilesional skin), lesional skin, and distant uninvolved skin from psoriasis patients. Perilesional epidermis contained numerous CD1a-positive Langerhans cells, some of which expressed HLA-DR, CD83, CD80, and CD86, at the same time expressing Langerin. There were also numerous CD83-positive, CD11c-positive, Langerin-negative clendritic cells (DCs) in the epidermal-dermal junction of perilesional skin. CD3-positive T lymphocytes were sparse in the perilesional skin. Perilesional epidermis expressed keratin K6 and K16, inflammatory keratins, and C/EBP beta, a transcription factor related to inflammatory cytokines. Our results demonstrated the abundant distribution of activated DCs in the perilesional skin of psoriatic plaques, where early inflammatory changes occur in the epidermal keratinocytes, which suggests their involvement in the provocation of epidermal inflammation in the perilesional epidermis and further pathogenic roles in the formation of psoriatic plaques.

The action of vitamin D-3 on Langerhans cells (LCs) is not well understood. Using highly purified murine LCs (> 95%), we investigated the direct action of 1 alpha,25-dihydroxyvitamin D-3 (1,25(OH)(3)D-3) on their functions. 1,25(OH)(2)D-3 inhibited the expression of cell surface molecules including I-A(d), CD40, CD80, and CD86, leading to impaired ability of LCs to stimulate allogenic T cells in the mixed leukocyte reaction. Furthermore, this reagent inhibited chemotaxis of LCs to CCL21 and their survival. Interestingly, 1,25(OH)(2)D-3 reduced the IL-10 production by LCs, whereas the production of IL-6 and IL-12p40 upon activation by CD40 ligation was enhanced. With regard to inflammatory cytokines and chemokines, 1,25(OH)(2)D-3 upregulated the production of IL-1 beta, CCL3, CCL4, and CCL5. The production of Th2-type chemokines, represented by CL17 and CCL22, was inhibited, whereas IFN-gamma-triggered production of Th1-type chemokines, represented by CXCL9, CXCL10, and CXCL11, was augmented. These data indicate that the mode of regulation of cytokine and chemokine production in association with 1,25(OH)(2)D-3 treatment seems to be another characteristic discriminating LCs from classical myeloid dendritic cells. (c) 2007 Elsevier Inc. All rights reserved.

CC chemokine ligand (CCL)17 is implicated in the pathogenesis of atopic dermatitis (AD). To study the effect of CCL17 produced by keratinocytes (KC) during inflammation, we created transgenic (Tg) mice in which CCL17 is overexpressed in KC. Th2-type contact hypersensitivity (CHS) was enhanced and Th1-type CHS was suppressed in these mice. Increased numbers of CC chemokine receptor (CCR)4(+) cells and mast cells infiltrated in Tg mice. Levels of IL-4 mRNA were higher and those of IFN-gamma mRNA were lower in both acute and chronic CHS. Higher levels of serum IgE were observed after CHS. Numbers of CCR4(+) cells among PBMC were increased in Tg mice challenged acutely on the trunk. Chronic irritation with croton oil induced dermatitis and an elevation of serum IgE levels. Tg mice showed enhanced ear swelling after tape stripping. CCL17 was thought to modify the inflammation caused by sensitizing reagents as well as irritant reagents by attracting CCR4(+) cells into the lesional skin and creating a Th2-dominant condition. AD-like conditions such as increased number of mast cells and elevated levels of serum IgE were observed. Thus, CCL17 may participate in the pathogenesis of skin diseases such as AD by regulating both allergic and irritant inflammation.

Necrolytic migratory erythema (NME) is an uncommon inflammatory dermatosis with a distinctive clinical and histological appearance. It shows irregular erythema, bullae, erosion, crusts and pigmentation. While it is typically associated with glucagonoma, some cases of NME without glucagonoma have been reported. Herein, we report a case of necrolytic migratory erythema associated with malabsorption 30 years after ileocolectomy. She presented erosive erythema with scale or partly flaccid bullae on her intergluteal cleft, buttock and extremities. Her laboratory data revealed essential amino acid deficiency and a slightly decreased serum zinc level, while her plasma glucagon level was low. With diagnosis of non-glucagonoma-associated NME with malabsorption due to short-bowel syndrome, she was treated and improved by i.v. amino acid supplement. Histological findings of NME include necrotic changes of keratinocytes in the upper epidermis, proliferation of those in the lower epidermis and inflammatory cell infiltration of upper dermis. We also examined the expression pattern of epidermal keratins (K6, K10) and Ki-67, one of the markers of proliferative activity, to assess the proliferation and differentiation of keratinocytes in a NME lesion by immunostaining. The findings with these immunostainings support the characteristics of HE-staining, and suggest hyponutrition may induce changing differentiation/proliferation of keratinocytes.

Background: Psoriasis is a T-helper (Th)1 cytokine-mediated chronic skin disease and interleukin (IL)-12 has been shown to play a major role in the development of Th1 responses. Objectives: To elucidate the role of IL-12 in the pathogenesis of psoriasis and to study the effect of ciclosporin A (CsA) on Th1 deviation of this disease. Patients/Methods: We investigated IL-12 production by stimulated monocytes from patients with psoriasis who were treated with or without CsA. Monocytes were stimulated with interferon-γ plus lipopolysaccharide (LPS) or Staphylococcus aureus Cowan strain I (SAC). The amount of IL-12 p70 produced by stimulated monocytes was evaluated by enzyme-linked immunosorbent assay. Results: Compared with those from normal controls, LPS- but not SAC-stimulated monocytes from patients with psoriasis produced significantly higher amounts of IL-12. Interestingly, LPS-stimulated monocytes from patients with psoriasis treated with CsA produced significantly decreased amounts of IL-12 compared with those patients not treated with CsA. Conclusions: Our results suggest that IL-12 production by monocytes may have a critical role in the pathogenesis of psoriasis, and that the therapeutic effect of CsA on psoriasis may be achieved by correcting the deviation of the Th1/Th2 balance. © 2006 British Association of Dermatologists.

Mechanical stretching represents an important part of the signaling in skin. We have previously demonstrated that mechanical stretching induced proliferative phenotypes in human keratinocytes, as shown in increased 5-bromo-2'-deoxyuridine (BrdU) incorporation, ERK1/2 activation, and keratin K6 induction. Here we have further investigated the antiapoptotic signals in human keratinocytes provoked by mechanical stretching in vitro. Keratinocytes were plated on flexible silicone supports to transmit mechanical stretching to keratinocytes, involving continuous stretching by +20%. Stretching of these cells for 15-30 min caused the phosphorylation and activation of Akt. Inhibition of mitogen and extracellular signal-regulated kinase (MEK1/2) with U0126 and phosphoinositide 3-OH kinase (PI 3-K) with Wortmannin attenuated Akt activation. The epidermal growth factor (EGF) receptor kinase inhibitor, AG1478, and calcium channel inhibitor, gadolinium (Gd3+), also inhibited Akt activation. In summary, our results demonstrate the activation of the Akt signaling pathway by mechanical stretching, generating not only proliferative but also antiapoptotic signals in human keratinocytes.

Both CCL27 and CCL28 are ligands for CCR10 and attract CCR10(+) lymphocytes. We previously demonstrated that CCL27 and CCL28 were strongly expressed in sera and lesional keratinocytes of patients with atopic dermatitis and psoriasis vulgaris. However, the regulation of CCL27 and CCL28 production in keratinocytes has not been well documented. In this study, we showed that CCL27 and CCL28 expression and production by a human keratinocyte cell line, HaCaT cells, were strongly induced by inflammatory cytokines tumor necrosis factor-alpha and interleukin-1 beta. CCL27 production was downregulated by inhibitors of p38 mitogen-activated protein kinase and nuclear factor-kappa B (NF-kappa B). By contrast, CCL28 production was downregulated by inhibitors of extracellular signal-regulated kinase and NF-kappa B. Our study results suggest that CCL28 produced by keratinocytes is mediated by different signal pathways from CCL27 and that both CCL27 and CCL28 are involved in the pathogenesis of inflammatory skin diseases.

Stimulation with tumor necrosis factor (TNF)alpha and interferon (IFN)gamma synergistically induced thymus- and activation-regulated chemokine (TARC)/CCL17 production from HaCaT keratinocytes (KC). Inhibitors for nuclear factor kappa B (NF kappa B), parthenolide, and Bay 11-7085, and an inhibitor of p38, SB202190, inhibited TNF alpha- and IFN gamma-induced production of CCL17 by HaCaT KC. Surprisingly, an inhibitor of epidermal growth factor receptor tyrosine kinase, PD153035, enhanced the production of CCL17 in HaCaT KC. Roxithromycin (RXM), a 14-membered ring macrolide, suppressed CCL17 production by HaCaT KC induced by IFN gamma and TNF alpha. RXM partially suppressed p38 phosphorylation and NF kappa B-driven luciferase activity induced by TNF alpha and IFN gamma. Degradation of inhibitor of nuclear factor kappa B (I kappa B) alpha upon stimulation with IFN gamma and TNF alpha was not affected by the addition of RXM. Through elucidating the mechanism of CCL17 production, our study indicates that RXM suppresses the production through the inhibition of p38 and NF kappa B, independent of the inhibition of I kappa B degradation.

Eotaxin-2/CCL24 and eotaxin-3/CCL26 are CC chemokines and their receptor, CC chemokine receptor 3 is preferentially expressed on eosinophils. It was reported that vascular endothelial cells and dermal fibroblasts produced CCL26. However, the regulation of CCL24 and CCL26 production in keratinocytes has not been well documented. We investigated the expression and production of CCL24 and CCL26 in the human keratinocyte cell line, HaCaT cells. Reverse transcription and polymerase chain reaction was performed using these cells and Enzyme-linked immunosorbent assay was carried out using supernatant of these cells. The production of CCL24 in HaCaT cells was slightly enhanced by IL-4 and that of CCL26 was strongly enhanced by IL-4 and IL-13. Furthermore, TNF-α generated a synergistic effect on IL-4 enhanced CCL26 production. Dexamethasone, IFN-γ and the p38 mitogen-activated protein kinase inhibitor SB202190 inhibited IL-4 enhanced CCL26 production. IL-4 enhanced production of CCL26 was inhibited by leflunomide and JAK inhibitor 1, but not by JAK3 inhibitor, which indicates that it is mediated by JAK1-STAT6-dependent pathway. This result also strongly suggests the involvement of the type 2 IL-4 receptor in IL-4 enhanced production of CCL26. These results suggest that keratinocytes are involved in the migration of CC chemokine receptor 3 positive cells such as eosinophils in a Th2-dominant situation like atopic dermatitis. © 2005 British Society for Immunology.

Leukotriene B4 (LTB4) is a potent chemoattractant and activator for granulocytes and macrophages and is considered to be an inflammatory mediator. Two G-protein-coupled receptors for LTB4, BLT1 and BLT2, have been cloned from human and shown to be high and low affinity LTB4 receptors, respectively. To reveal the biological roles of BLT2 using mouse disease models, we cloned and characterized mouse BLT2. Chinese hamster ovary cells stably expressing mouse BLT2 exhibited specific binding to LTB4, LTB4-induced calcium mobilization, inhibition of adenylyl cyclase, and phosphorylation of extracellular signal-regulated kinase. We found that Compound A (4'-{[pentanoyl (phenyl) amino] methyl}1, 1'-biphenyl-2-carboxylic acid) was a BLT2-selective agonist and induced Ca2+ mobilization and phosphorylation of extracellular signal-regulated kinase through BLT2, whereas it had no effect on BLT1. 12-epi LTB4 exhibited a partial agonistic activity against mBLT1 and mBLT2, whereas 6-trans-12-epi LTB4 did not. Northern blot analysis showed that mouse BLT2 is expressed highly in small intestine and skin in contrast to the ubiquitous expression of human BLT2. By in situ hybridization and the reverse transcriptase polymerase chain reaction, we demonstrated that mouse BLT2 is expressed in follicular and interfollicular keratinocytes. Compound A, LTB4, and 12-epi LTB4 all induced phosphorylation of extracellular signal-regulated kinase in primary mouse keratinocytes. Furthermore, Compound A and LTB4 induced chemotaxis in primary mouse keratinocytes. These data suggest the presence of functional BLT2 in primary keratinocytes.

Background: Thymus and activation-regulated chemokine (TARC) plays an important role in the pathogenesis of atopic dermatitis (AD). We recently detected the single nucleotide polymorphism (SNP) (-431C>T) in the 5'-flanking region of TARC gene. Objectives: To examine whether the -431C>T SNP of the TARC gene is associated with susceptibility to AD and whether it affects the promoter activity of the TARC gene. Methods: We investigated the genotype and allele frequencies of the SNP in 193 AD patients and 158 healthy controls by polymerase chain reaction-restriction fragment length polymorphism method. We compared the promoter activities between TARC promoter carrying 431C and that carrying -431T by transient-transfection assay in DJM-1 cell line. Results: There were no significant differences in genotype or allele frequencies between AD patients and controls (genotype: P = 0.38, allele: P = 0.22). Luciferase activity was higher in -431T constructs than in -431C constructs (2.3-fold, P = 9.5 x 10(-6)). Conclusion: These results suggest that the -431C>T SNP of the TARC gene enhances the promoter activity of TARC gene but is not associated with susceptibility to AD in Japanese population.

Epidermal keratinocytes are continuously exposed to mechanical forces. The human skin surface can be thickened and enlarged by various stresses such as tissue expander or abrasive pressure. To investigate the mechanism of epidermal hyperproliferation by mechanical stress, keratinocytes were plated on flexible silicone dishes, which were continuously stretched by + 20%. Stretching of cells for 24 h caused upregulation of 5-bromo-2'-deoxyuridine (BrdU)-positive cells to 200%-220% and activation of extracellular signal-regulated kinases (ERK)1/2. Inhibition of mitogen and ERK with U0126 and phosphoinositide 3-OH kinase attenuated BrdU incorporation and ERK1/2 activation. The EGF receptor kinase inhibitor and the calcium channel inhibitor also inhibited BrdU incorporation and the activation of ERK1/2. Twenty-four hours of stretching stimulated reporter activity driven by activator protein 1(AP-1), induction of K6, and suppression of K10, which were inhibited by U0126. Our results indicate that mechanical stretching induces proliferative signals on human keratinocytes via induction of calcium influx, phosphorylation of epidermal growth factor receptor (EGFR), and ERK1/2. These mechanisms may contribute to the hyperproliferative nature of the epidermis, which is mechanically stretched by various stimuli.

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease characterized by the predominant infiltration of T cells, eosinophils and macrophages in lesional skin. Recently, eotaxin-2/ CCL24 and eotaxin-3/ CCL26 were identified as CC chemokines that signal exclusively via the CCR3 receptor and have eosinophil-selective chemoattractant activity, as does eotaxin/CCL11. We previously reported that serum levels of thymus and activation-regulated chemokine (TARC)/CCL17 and macrophage-derived chemokine (MDC)/CCL22 were correlated with the severity of AD. In this report, we investigated the participation of eotaxin-2/CCL24 and eotaxin-3/CCL26 in AD, first measuring the serum levels of eotaxin-2/CCL24 and eotaxin-3/CCL26 in 30 patients with AD, 20 patients with psoriasis vulgaris and 20 healthy controls. The serum levels of eotaxin-3/CCL26 (but not eotaxin-2/CCL24) were significantly higher in patients with AD than in either healthy controls or patients with psoriasis vulgaris furthermore, the eotaxin-3/CCL26 levels in patients with moderate and severe AD were significantly higher than eotaxin-3/CCL26 levels in patients with mild AD. The serum eotaxin-3/CCL26 levels tended to decrease after treatment, but there was no significant difference between groups. Moreover, the serum eotaxin-3/CCL26 levels were significantly correlated with the serum TARC/CCL17 and MDC/CCL22 levels, eosinophil numbers in peripheral blood and the scoring AD (SCORAD) index. Our study strongly suggests that serum levels of eotaxin-3/CCL26, but not of eotaxin-2/CCL24, have a notable correlation with disease activity of AD and that eotaxin-3/CCL26, as well as TARC/CCL17 and MDC/CCL22, may be involved in the pathogenesis of AD.

Background: Macrophage-derived chemokine (MDC) is a Th2 type chemokine and its receptor CC chemokine receptor 4 (CCR4) is preferentially expressed on Th2 cells. Recent reports demonstrated that MDC is expressed not only by macrophages,, dendritic cells and lymphocytes, but also by cultured human keratinocytes (KCs). However, the regulation of MDC production in KCs by various cytokines has not been well documented. Objective: In this study, we investigated how Th1/Th2 cytokines regulate MDC production in a human KC cell line, HaCaT cells. Methods: HaCaT cells were cultured with or without various cytokines for 24 h and RT-PCR was performed using these cells to evaluate MDC mRNA levels. ELISA was carried out using supernatant of HaCaT cells to calculate secreted MDC protein levels. Results: MDC mRNA was weakly expressed in HaCaT cells, and upon stimulation with TNF-alpha or IFN-gamma, MDC expression was strongly upregulated. The supernatant MDC levels when stimulated with TNF-alpha or IFN-gamma were significantly higher than those without stimulation, and were synergistically increased when stimulated with a combination of TNF-alpha and IFN-gamma. Both interteukin-4 (IL-4) and IL-13 inhibited TNF-alpha and IFN-gamma enhanced MDC production in HaCaT cells in a dose-dependent manner. Conclusion: Th2-type cytokines IL-4 and IL-13 downregulate the production of MDC, a Th2 type chemokine, by KCs. This may partially contribute to maintaining Th1/Th2 balance inflammatory skin diseases like atopic dermatitis. (C) 2002 Japanese Society for Investigative Dermatology Elsevier Science Ireland Ltd. All rights reserved.

Both atopic dermatitis (AD) and psoriasis vulgaris (PsV) are characterized as chronic and relapsing inflammatory skin diseases associated with various immunologic abnormalities. Cutaneous T cell-attracting chemokine (CTACK; CCL27) is a member of the CC chemokine family and a functional ligand for CC chemokine receptor 10. It is selectively expressed in skin and attracts CC chemokine receptor 10-expressing skin-homing memory T cells. The epidermal keratinocyte is a main source of CTACK, suggesting the involvement of various inflammatory skin diseases. Objective: The purpose of this investigation was to clarify whether CTACK produced by keratinocytes is detected in the sera of patients with AD and PsV and to examine the correlation between the serum CTACK levels and disease activity of patients with AD and PsV. Methods: We measured the serum CTACK levels in 50 patients with AD, 30 patients with PsV, and 22 healthy control subjects. We also divided 50 patients with AD into 3 groups (ie, those with mild, moderate, and severe disease) and compared them among 3 categories. Moreover, we compared the serum CTACK levels of patients with AD and PsV with clinical or laboratory data. Immunohistochemical staining of CTACK and IFN-induced protein of 10 kd (IP-10; CXCL10) was performed on the lesional skin of patients with AD and PsV. Results: The serum CTACK levels in,patients with AD and PsV were significantly higher than those in healthy control subjects. The serum CTACK levels in patients with AD significantly correlated with scoring atopic dermatitis (SCORAD) scores, serum soluble IL-2 receptor levels, serum soluble E-selectin levels, serum thymus and activation-regulated chemokine levels, and serum macrophage-derived chemokine levels. Serum CTACK levels in patients with PsV significantly correlated with the serum IP-10 levels but not with the Psoriasis Area and Severity Index score. Immunohistochemical staining showed CTACK was strongly expressed in lesional keratinocytes of patients with AD and PsV, whereas IP-10 was strongly expressed in lesional keratinocytes of patients with PsV and focally in those with AD. Conclusion: These results suggest that CTACK might be one of the important chemokines for the pathogenesis of AD and PsV.

Interleukin 15 (IL-15) is a potent stimulator of proliferation and an inhibitor of apoptosis in lymphocytes. We attempted to elucidate the mechanism of IL-15 function in HaCaT keratinocytes. We found that 5-bromo-2'-deoxyuridine incorporation increased in a dose-dependent manner with IL-15. This was blocked by MEK inhibitor U0126 or PI 3-K inhibitor LY294002. ERK1/2 and Akt phosphorylation by IL-15 were detected in a dose- and time-dependent manner. U0126 and LY294002 abolished ERK1/2 and Akt phosphorylation, respectively. DNA fragmentation and Annexin V binding accompanied by UVB-induced apoptosis were reduced by 30-50% with IL-15. Taken together, IL-15 induced cellular proliferation and had an anti-apoptotic effect on keratinocytes, in which ERK1/2 and Akt phosphorylation played crucial roles. The signal transduction pathways of IL-15 in keratinocytes were partially elucidated; they share a substantial part with growth signals induced by EGF. These results suggest a therapeutic approach to inflammatory skin diseases by controlling these signals. (C) 2003 Elsevier Science (USA). All rights reserved.