Hitoaki Okazaki

Lysophosphatidylcholine induces apoptosis in human endothelial cells through a p38-mitogen-activated protein kinase-dependent mechanism.

Lysophosphatidylcholine (lysoPC) is a component of oxidized low density lipoprotein (LDL) and is involved in the pathogenesis of atherosclerosis and inflammation. Previous studies demonstrated that lysoPC can induce various protein kinases including tyrosine kinases, protein kinase C (PKC), and mitogen-activated protein kinases (MAPK) in vascular endothelial cells. However, the role of lysoPC-activated kinases remains undefined. In this study, we examined the effect of lysoPC on apoptosis and investigated the role of lysoPC-activated protein kinases in human umbilical vein endothelial cells (HUVEC). The presence of apoptosis was evaluated by morphological criteria, MTT assay, and electrophoresis of DNA fragments showing the characteristic apoptotic ladder, TUNEL analysis, and quantified as the proportion of hypodiploid cells by flow cytometry. The lysoPC induced apoptosis in a time- and dose-dependent manner. It stimulated the phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2) and p38-MAPK in HUVEC. The use of specific pharmacologic inhibitors indicated that the p38-MAPK-signaling pathway (SB203580) is required for lysoPC-induced apoptotic signals. Furthermore, lysoPC-induced apoptosis was inhibited by DEVD-FMK (a caspas-3/CPP32 inhibitor), suggesting involvement of an important segment in the apoptosis. These results demonstrate that lysoPC induces apoptosis in human endothelial cells through a p38-MAPK-dependent pathway.

Increased Levels of Interleukin 33 in Sera and Synovial Fluid from Patients with Active Rheumatoid Arthritis

Objective. To determine levels of interleukin 33 (IL-33) in serum and synovial fluid (SF) and their clinical associations in patients with rheumatoid arthritis (RA). To evaluate the ability of activated peripheral blood mononuclear cells (PBMC) and fibroblast-like synoviocytes (FLS) from RA patients to release IL-33. Methods. Sera were obtained from 59 patients with RA, 10 patients with infectious diseases, and 42 healthy volunteers. SF samples were obtained from 15 patients with RA and 13 with osteoarthritis. IL-33 levels were measured using a sandwich ELISA after removal of rheumatoid factor with protein A-Sepharose beads. FLS were stimulated with IL-1ß and tumor necrosis factor, and treated with or without chemical damage. PBMC were stimulated with anti-CD3/CD28 antibodies. The levels of IL-33 were measured in the culture supernatants and cell lysates by ELISA or immunoblotting. Results. Serum IL-33 levels were significantly higher in RA patients, especially in the high disease activity group compared to the moderate or low activity group. IL-33 levels in SF were elevated in all 15 RA patients measured. IL-33 levels were higher in SF samples than in sera in 7 RA patients measured simultaneously. The 30-kDa IL-33 precursor was detected in the culture supernatants of damaged FLS but was not detected in those of activated PBMC and non-damaged FLS. Conclusion. IL-33 levels were elevated in sera and SF samples from patients with RA, and correlated with disease activity. IL-33 was produced mainly in inflamed joints; IL-33/ST2L signaling might play an important role in joint inflammation of human RA.

Mature interleukin-33 is produced by calpain-mediated cleavage in vivo

Interleukin (IL)-33 is a novel member of the IL-1 family. IL-33 is primarily synthesized as a 30-kDa precursor (pro-IL-33). Pro-IL-33 is cleaved by caspase-1 into an 18-kDa mature form (mature IL-33) in vitro. Recombinant mature IL-33 has been known to induce T-helper type-2 (Th2)-associated cytokines and inflammatory cytokines via its receptor, ST2L. However, processing of pro-IL-33 in vivo has not been clarified yet. Here, we report that calpain mediates pro-IL-33 processing in vivo. Pro-IL-33 was expressed by stimulating human epithelial cells with phorbol 12-myristate 13-acetate. Calcium ionophore induced pro-IL-33 cleavage and mature IL-33 production. This cleavage was inhibited by treatment with a calcium chelator and calpain inhibitors. Moreover, short interfering RNA-mediated knockdown of calpains suppressed pro-IL-33 cleavage. These results indicate that calpains play a critical role in pro-IL-33 processing in vivo.

Nocardia arthritidis sp. nov., a New Pathogen Isolated from a Patient with Rheumatoid Arthritis in Japan

ABSTRACT Two different bacterial strains with different drug susceptibilities were isolated from the sputum and an inflammatory discharge from a swelling in the left thigh of a patient with rheumatoid arthritis. Both bacterial strains were provisionally assigned to the genus Nocardia on the basis of their morphological and chemotaxonomic characteristics and were further studied in order to establish their taxonomic status. One strain (IFM 10034) was identified as Nocardia farcinica on the basis of its physiological characteristics. The other strain, which was designated Nocardia sp. strain IFM 10035T, revealed a unique pattern of phenotypic properties that distinguished it from other representatives of established Nocardia species. Comparative 16S rRNA gene sequence studies of Nocardia sp. strain IFM 10035T also showed that the bacterium was closely related to the species Nocardia beijingensis. Determination of DNA-DNA relatedness, however, indicated that Nocardia sp. strain IFM 10035T could be delineated from N. beijingensis. The genotypic and phenotypic data combined indicated that the bacterium merits description as a new Nocardia species. The name proposed for the new species is Nocardia arthritidis sp. nov., the type strain being IFM 10035T (NBRC 100137T, JCM 12120T, DSM44731T). The present study suggests that Nocardia infections can be caused by multiple species of the bacterium.

Characterization of chemokine receptor expression and cytokine production in circulating CD4+ T cells from patients with atopic dermatitis: up-regulation of C-C chemokine receptor 4 in atopic dermatitis.

Background Th2 and Th1 cells have been suggested to express CCR3/CCR4 and CCR5/CXCR3, respectively.

Subarachnoid hemorrhage and systemic lupus erythematosus

The frequency, clinical profile, treatment and outcome of subarachnoid hemorrhage (SAH) in patients with systemic lupus erythematosus (SLE) were assessed retrospectively, based on the case records of SLE of the Jichi Medical School Hospital over a 20 year period. Clinically defined SAH was found in 10 (3.9%) out of 258 SLE patients, which represented a frequency higher than previously assumed. Five patients had active SLE and lacked an apparent cause of SAH, other than SLE. A high mortality rate (5=5), no visible aneurysm on angiogram (3=4), and an onset during intractable SLE or after discontinued or no steroid therapy because of medical noncompliance (4=5) were characteristic of patients with active SLE, and thus an earlier successful suppression of SLE, if possible, might have prevented their SAH. In contrast, in the 5 patients with inactive SLE, 2 out of 3 saccular aneurysms were succcessfuly clipped and small bleeding of one patient without aneurysms remitted spontaneously without the need for additional steroid therapy. When one death, which occurred outside of medical care, was excluded, the survival ratio of the hospitalized SAH patients with inactive SLE was significantly better than that with active SLE (3=4 versus 0=5, P ‘ 0.0476). In conclusion, the relatively common occurence of SAH in SLE patients, and a significantly different clinical impact of SAH in respect to active and inactive SLE, were suggested from the results.

Acute acalculous cholecystitis in systemic lupus erythematosus: a case report and review of the literature

A 27-year-old woman with systemic lupus erythematosus (SLE) was found to have acute acalculous cholecystitis. At the time of admission, the patient was not under corticosteroid or immunosuppressive therapy. Computed tomography (CT) and ultrasonography revealed findings in the gall bladder consistent with acute acalculous cholecystitis. Her abdominal pain completely disappeared following corticosteroid therapy, with dramatic improvement in the images of CT and ultrasonography. Six similar cases of SLE complicated with acute acalculous cholecystitis have been reported in the literature and they were all treated surgically by cholecystectomy or cholecystostomy. This is the first case report in which acute acalculous cholecystitis accompanying SLE was treated successfully by corticosteroid without surgical intervention.

Muscular polyarteritis nodosa as a cause of fever of undetermined origin: a case report and review of the literature

We describe an unusual presentation of a localized form of polyarteritis nodosa (PAN) manifested by fever of undetermined origin (FUO). Biopsies of the gastrocnemius muscle revealed necrotizing arteritis and initiation of prednisolone (PSL) brought rapid response. The PAN localized to muscle is rare; furthermore, this disease presented as FUO is very rare. We want to increase awareness that muscle can be also a single-affected site as well as other well known sites such as appendix, gallbladder, uterus or testis, and skin. Since there is no single appellation for this disease, we would like to propose the term “muscular PAN.”

A case of rheumatoid arthritis with protein losing enteropathy induced by multiple diaphragmatic strictures of the small intestine: successful treatment by bougieing under double-balloon enteroscopy

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most favoured for the treatment of rheumatoid arthritis (RA) but they sometimes induce inflammation and ulceration of the gastrointestinal tract.1 Approximately 75% of patients receiving long term NSAIDs develop inflammation in the small intestine that in rare cases results in protein losing enteropathy.2,3 Furthermore, NSAIDs can bring about diaphragmatic strictures in the small intestine as a consequence of ulcer healing. We report here a patient with RA who had multiple diaphragmatic strictures in the small intestine and subsequent protein losing enteropathy, probably due to long term non-steroidal anti-inflammatory drugs use. Her intestinal stricture and protein losing enteropathy, however, were successfully corrected by bougieing under double balloon enteroscopy without resort to surgical resection. A 57 year old …

Fluvastatin enhances apoptosis in cytokine-stimulated vascular smooth muscle cells

Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) have been shown to attenuate proliferation of vascular smooth muscle cells (VSMCs) by mechanisms independent of lipid reduction. In the current study, we investigated the effect of lipophilic and hydrophilic statins (fluvastatin and pravastatin) on apoptosis in unstimulated or cytokine-stimulated VSMCs. The presence of apoptosis in rat VSMCs was evaluated by electrophoresis of DNA fragments and 4´,6´-diamidine-2´-phenylindole staining and quantified by flow cytometry. Fluvastatin but not pravastatin enhanced apoptosis in interleukin-1&bgr;-stimulated VSMCs. The proapoptotic effect of fluvastatin was fully reversed by mevalonate and geranylgeranyl-pyrophosphate, and partially by farnesyl-pyrophosphate, but not by squalene. Inhibition of the extracellular signal-regulated protein kinase (ERK1/2) pathway significantly increased fluvastatin-enhanced apoptosis, whereas inhibition of the p38-mitogen-activated protein kinase (MAPK) pathway significantly prevented this increase. However, fluvastatin showed no effect on the activity of ERK1/2 and p38-MAPK. Furthermore, fluvastatin-induced apoptosis was inhibited by YVAD-FMK (a caspase-1/interleukin-1&bgr;-converting enzyme-like protease inhibitor) and DEVD-FMK (a caspase-3/CPP32 inhibitor), indicating involvement of an important segment in the apoptosis signaling pathway. These findings suggest that fluvastatin enhances apoptosis in cytokine-stimulated VSMCs and that protein prenylation, MAPK (ERK1/2 and p38-MAPK), and caspases are critically involved in the pathways of fluvastatin-enhanced apoptosis.