Yuko Yamakawa

Involvement of Rho-Kinase in Angiotensin II–Induced Hypertrophy of Rat Vascular Smooth Muscle Cells

Angiotensin II (Ang II) is now believed to play a critical role in the pathogenesis of hypertrophy and/or hyperplasia of vascular smooth muscle cells (VSMCs). Several G(i)- and G(q)-coupled receptors, including the Ang II type 1 (AT(1)) receptor, activate Rho and Rho-associated kinase in Swiss 3T3 cells and cardiac myocytes. However, little is known about the role of Rho-kinase in Ang II-induced vascular hypertrophy in VSMCs. In the present study, we explored the role of Rho and Rho-kinase in Ang II-induced protein synthesis in VSMCs. In unstimulated cells, RhoA was observed predominantly in the cytosolic fraction, but it was translocated in part to the particulate fraction in response to Ang II (100 nmol/L). This effect was completely blocked by the AT(1) receptor blocker candesartan but not by the Ang II type 2 (AT(2)) receptor antagonist PD123319. Botulinum C(3) exoenzyme, which inactivated RhoA, attenuated Ang II-induced [(3)H]leucine incorporation. The specific Rho-kinase inhibitor, Y-27632, dose-dependently abolished Ang II-induced protein synthesis and also suppressed Ang II-induced c-fos mRNA expression. On the other hand, Y-27632 had no effect on Ang II-stimulated phosphorylation of p70 S6 kinase and extracellular signal-regulated kinase 1/2, which are reported to be involved in Ang II-induced protein synthesis, nor had it any effect on the Ang II-induced phosphorylation of PHAS-I, a heat- and acid-stable eIF-4E-binding protein. The phosphorylation of PHAS-I is regulating for translation initiation. These observations suggest that the Rho, Rho-kinase, and c-fos pathways may play a role in Ang II-induced hypertrophic changes of VSMCs through a novel pathway.

Carbamazepine‐induced hypersensitivity syndrome associated with transient hypogammaglobulinaemia and reactivation of human herpesvirus 6 infection demonstrated by real‐time quantitative polymerase chain reaction

Summary Drug‐induced hypersensitivity syndrome (HS) is a rare but severe disease with multiorgan failure. Many different precipitating factors have been reported, but the pathophysiology of HS remains unknown. However, the association of the human herpesvirus (HHV) family, particularly of HHV‐6, has recently been reported in patients with HS. We report a 14‐year‐old boy who was diagnosed as having carbamazepine‐induced HS based on the clinical course, laboratory data and results of drug‐induced lymphocyte stimulation tests. In addition, the reactivation of HHV‐6 was demonstrated by real‐time quantitative polymerase chain reaction and by significantly increased levels of the specific antibody in his paired sera. Furthermore, transient hypogammaglobulinaemia was detected in the early stage of the disease. In addition, serum levels of interferon‐γ, interleukin (IL)‐6, IL‐5 and eosinophil cationic protein, which were increased on admission, decreased dramatically after steroid therapy. This is the first report of carbamazepine‐induced HS associated with reactivation of HHV‐6, transient hypogammaglobulinaemia, increased serum levels of inflammatory cytokines and activated eosinophils. This case might contribute to the understanding of the pathophysiology of HS.

Lysophosphatidylcholine Stimulates MAP Kinase Activity in Rat Vascular Smooth Muscle Cells

Lysophosphatidylcholine (lyso-PC) has been implicated in atherogenesis and the inflammatory process. Although lyso-PC has been reported to contribute to the mitogenic effect of oxidized LDL on rat cultured vascular smooth muscle cells (VSMCs), the signaling mechanisms by which lyso-PC promotes its proliferation are poorly characterized. Mitogen-activated protein (MAP) kinases are important mediators involved in the intracellular network of interacting proteins that transduces extracellular cues to intracellular responses. We therefore examined the effect of lyso-PC on MAP kinase activation, proto-oncogene expression, and AP-1 binding activity using cultured rat VSMC. Marked activation of MAP kinase occurred within 10 minutes of lyso-PC treatment, whereupon rapid inactivation ensued. MAP kinase activation by lyso-PC was concentration-dependent (6.25 to 25 micromol/L). Pertussis toxin treatment did not affect lyso-PC-induced MAP kinase phosphorylation. Lyso-PC (25 micromol/L) also increased the mRNA expression of c-fos and c-jun genes. An electrophoretic mobility shift assay showed that AP-1 binding activity was enhanced by lyso-PC. To examine the upstream signaling of MAP kinase, we used several inhibitors on MAP kinase activation induced by lyso-PC. Although lyso-PC induced sustained increase in intracellular Ca2+ concentration, EGTA had no effect on MAP kinase activation induced by lyso-PC. However, protein kinase C inhibitor GF109203X and downregulation of protein kinase C activity by prolonged treatment with phorbol ester inhibited lyso-PC-induced MAP kinase activation. These data suggest that lyso-PC transmits its mitogenic activity through a MAP kinase-AP-1 pathway, which exists downstream of its protein kinase C activation in VSMCs.

Lysophosphatidylcholine Activates Extracellular Signal-Regulated Kinases 1/2 Through Reactive Oxygen Species in Rat Vascular Smooth Muscle Cells

Lysophosphatidylcholine (lysoPC) acts on vascular smooth muscle cells (VSMCs) to produce a mitogenic response through the activation of extracellular signal-regulated kinases 1/2 (ERK1/2). In the present study, we examined the importance of reactive oxygen species (ROS) in lysoPC-stimulated ERK1/2 activation in cultured rat VSMCs. Treatment with lysoPC for 3 minutes caused a 2-fold increase in intracellular ROS that was blocked by the NADH/NADPH oxidase inhibitor, diphenylene iodonium (DPI). Antioxidants, N-acetyl-l-cysteine, glutathione monoester, or &agr; -tocopherol, inhibited ERK1/2 activation by lysoPC. Almost identical results were obtained in the VSMC line A10. Pretreatment of VSMCs with DPI but not allopurinol or potassium cyanide (KCN) abrogated the activation of ERK1/2. The Flag-tagged p47phox expressed in A10 cells was translocated from the cytosol to the membrane after 2 minutes of stimulation with lysoPC. The overexpression of dominant-negative p47phox in A10 cells suppressed lysoPC-induced ERK activation. The ROS-dependent ERK activation by lysoPC seems to involve protein kinase C- and Ras-dependent raf-1 activation. Induction of c-fos expression and enhanced AP-1 binding activity by lysoPC were also inhibited by DPI and NAC. Taken together, these data suggest that ROS generated by NADH/NADPH oxidase contribute to lysoPC-induced activation of ERK1/2 and subsequent growth promotion in VSMCs.

INTERLEUKIN-6 (IL-6) IN PATIENTS WITH BEHCET'S DISEASE

We have examined the levels of interleukin-6 (IL-6) in plasma and supernatants of peripheral blood mononuclear cells (PBMC) from patients with Behçets disease and healthy controls using a sensitive enzyme-linked immunosorbent assay (ELISA). Plasma IL-6 level was not detected in any subjects. The IL-6 concentrations in culture supernatants of patients with active Behçets disease were significantly high compared with patients with inactive disease and healthy controls. Moreover, we investigated IL-6 gene expression in cultured PBMC from patients with Behçets disease. IL-6 gene expression was enhanced in active patients compared with inactive patients. These results show that IL-6 may play a role in the pathogenesis of Behçets disease.

Contact urticaria from rice

A 30‐year‐old man with atopic dermatitis had had erythema and itching of the hands after washing rice in water, though he had always eaten cooked rice without problems. Handling test with water used to wash regular rice was performed on abraded hands, and produced urticarial erythema after several minutes. Applications of water used to wash allergen‐reduced rice were negative for urticarial reaction. Prick test with water used to wash regular rice was +++. However prick test reaction with water used to wash allergen‐reduced rice was +. Histamine‐release test of regular rice‐washing water was grade 3 and that of allergen‐reduced rice grade 1. In immunoblotting analysis with regular rice washing water, there were no bands with this patient. These results suggest that the allergen responsible for contact urticaria in this patient might be water‐soluble, heat‐unstable, and not contained in allergen‐reduced rice.

Gene expression of tumour necrosis factor-α (TNF-α) and heat-shock protein (HSP) 70 in patients with BehÇet's disease

Department of Dermatology, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236, Japan 2 Third Department of Internal Medicine, Yokohama City University School of Medicine, 3 9 Fukuura, Kanazawa-ku, Yokohama 236, Japan 3 Department of Ophthalmology, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236, Japan 4 Department of Bacteriology, Yokohama City University School of Medicine, 3 9 Fukuura, Kanazawa-ku, Yokohama 236, Japan

Contact urticaria syndrome caused by patch testing with cefotiam hydrochloride.

Comment Isopropanolamine (CAS 78-96-6) is a buffering agent used in cosmetics, particularly gels, and in hair perms, hair sprays and tanning lotions (1). It has not previously been known to cause allergic contact dermatitis. Topical non-steroidal anti-inflammatory preparations are a wellestablished cause of contact allergy, photoallergy and phototoxicity (2), usually due to the active component rather than the vehicle. In Austria, the sensitization rate to bufexamac has been estimated at 4%, leading to suggestion for inclusion in the standard series (3). We considered the possibility that the patch test reaction to isopropanolamine was irritant, though its morphology and timing were more consistent with an allergic reaction. Patch testing 22 patients as controls, with isopropanolamine 1% aq., resulted in a slight irri-

A Case of Cutaneous T Cell Pseudolymphoma in a Patient with Helicobacter pylori Infection

Cutaneous pseudolymphomas (CPL) are benign cutaneous lymphoproliferative infiltrations of various origin, including among others bacterial infections, viral infections and drugs . Helicobacter pylori has been frequently founded in the stomach of patients with MALT lymphoma. In January 2001, a 43-year-old man was referred to our department because of a 1-month history of itchy erythematous patches, plaques and flat tumors on his body. Histological examination revealed nodular infiltrations composed of lymphocytes, plasma cells and histiocytes with exocytosis of lymphocytes within the epidermis. Molecular analysis of rearrangement of T cell receptor and immunoglobulin heavy-chain genes did not reveal monoclonality. Based on these clinical, laboratory and histopathological data, a diagnosis of cutaneous T cell pseudolymphoma (CTPL) was made. The patient was anti-H. pylori antibody-positive, and was treated with anti-H. pylori combination with the result that all of the tumors had disappeared by January 2002. The patient has maintained complete response up to the last follow-up visit in December 2005.

Demonstration of antigen-specific immune response against Streptococcus sanguis

The genetic control of Streptococcus sanguis antigen response was studied. Mice sensitized with inactivated S. sanguis organisms antigen-injected at the base of the tail developed footpad swelling. Those with an I-Ak,q,r region of H-2 showed a strong footpad response, whereas those with an I-Ab,d,s region showed a weak response to S. sanguis cell wall antigen. Footpad response was mediated by CD4+,8- T cells by using in vitro monoclonal antibody treatment. Similar evidence of genetic control was obtained with an in vitro T cell proliferation assay. However, quantitation of antibodies against S. sanguis showed that antibody production was not controlled by H-2. These results indicated that both in vivo footpad swelling and in vitro T cell proliferation responses were functions of helper (CD3+,4+,8-) T cells and controlled by the I-A region of H-2.