Regulation of nuclear factor of activated T-cell family transcription factors during T-cell development in the thymus

BACKGROUND

T lymphocytes undergo a series of developmental events in the thymus, and signaling through the T-cell antigen receptor is crucial in this differential program. The nuclear factor of activated T cells (NFATs) may be involved in transcriptional induction of cytokine genes and other immunoregulatory genes in T cells.

OBJECTIVES

We have examined the distribution of 3 NFAT family members (NFAT1, NFATc, and NFATx) in human fetal thymocytes, by using semiquantitative RT-PCR and electrophoretic mobility shift assay.

RESULTS

The messenger RNA of NFATx was expressed in all T-lymphocyte subsets tested, and expression was highest in CD4(+)CD8(+) thymocytes. Conversely, mRNA of NFAT1 was preferentially expressed in mature CD4(+) single-positive cells. NFATc mRNA was present at low levels in all subsets but was strongly induced by treatment with phorbol ester plus calcium ionophore. Using electrophoretic mobility shift assay, we observed stimulation-dependent NFAT-DNA binding in CD4(+)CD8(+) thymocytes, which was largely dependent on NFATx protein. This DNA-binding activity was inhibited by cyclosporin A, which indicated that NFATx nuclear translocation in CD4(+)CD8(+) thymocytes was regulated by calcineurin phosphatase. In contrast, NFAT1 and NFATc (and to some extent NFATx) were responsible for NFAT DNA binding in the CD4(+) cells.

CONCLUSIONS

Expression of NFAT family members is differentially regulated during T-cell development, and NFATx may be involved in T-cell antigen receptor/calcineurin-dependent signaling in CD4(+)CD8(+) thymocytes.

Corticobasal degeneration: an autopsy case clinically diagnosed as progressive supranuclear palsy

We report an autopsy case diagnosed clinically as progressive supranuclear palsy (PSP), but neuropathologically confirmed as corticobasal degeneration (CBD). A 56-year-old Japanese woman slowly developed parkinsonism, dementia, character change, followed by vertical gaze palsy and dystonia. Brain MRI demonstrated diffuse cerebral atrophy with severe shrinkage of the brain stem tegmentum. The SPECT images using 123I-IMP disclosed symmetrical hypoperfusion in the frontal lobes. She died of respiratory failure at the age of 71. Gross inspection of the brain showed diffuse, symmetrical atrophy of the cerebrum and marked atrophy of the Luysian body, globus pallidus, substantia nigra and nuclei of the brain stem tegmentum. Microscopically, neuronal loss and fibrillary gliosis were observed in the Luysian body, globus pallidus, substantia nigra and nuclei of the brain stem tegmentum. The cerebellar dentate nucleus showed mild neuronal loss with some grumose degeneration. Neurofibrillary tangles were found only in the Luysian body, substantia nigra and raphe nuclei, whilst tau-positive inclusions were observed more extensively. Astrocytic plaques and swollen achromatic neurones were found in the postcentral gyrus. There were no tuft-shaped astrocytes in the brain. The clinicopathological similarities and differences between PSP and CBD are discussed.

Long-term result of arterial grafts interposed for arterial defects using the telescoping anastomotic technique: histological and angiographic study

The arterial grafting model for arterial defects provides an ideal environment for the microvascular telescoping anastomosis because tension of the repaired vessel is maintained low and deformities of the inserted vessel end is minimal due to the thick arterial wall. The left femoral artery was grafted in 46 rats into the defect created in the right femoral artery using the telescoping anastomotic technique at both the proximal and distal anastomoses. The grafts were seen histologically and angiographically 3 to 4 months postoperatively in order to fairly evaluate the telescoping anastomosis in terms of long-term patency, stenosis, and changes in the outer and inner walls at the anastomosis. All arterial grafts were patent 3 to 4 months postoperatively and there were no aneurysms at the anastomoses. Enlargement of the graft diameter was minimal. The rate of stenosis at the anastomosis was smaller than that 1-day postoperatively. Even though the thick arterial wall was initially inserted and the intimal hyperplasia was still present at the anastomosis 3 to 4 months postoperatively, the long-term stenosis was relatively mild due to the atrophy in the overlapped walls.

NFATz: a novel rel similarity domain containing protein

Nuclear Factor of Activated T cell (NFAT) is a family of transcription factors that are important for the coordinate expression of various cytokines and immunoregulatory cell surface molecules in T cells and other types of cells in the immune system. In addition, analysis of gene disrupted mice revealed that some members of NFAT family are important for the development of myocardium, myocardial hypertrophy, and mesenchymal stem cells. NFAT family proteins have two conserved domains, the NFAT Homology Domain (NHD) and the Rel Similarity Domain (RSD). The RSD is DNA binding and AP-1 interacting domain which has structural similarity to the Rel Homology Region, the DNA binding domain of Rel family proteins. The NHD is a regulatory domain required for the Ca regulated translocation of NFAT. We report here the isolation and initial characterization of a novel RSD containing protein designated NFATz. NFATz has a RSD but no NHD. NFATz protein is localized in the nucleus without Ca signal. There is no detectable binding to a typical NFAT site even in the presence of AP-1, and it is not capable of activating transcription through the NFAT site. The chromosomal location determined by FISH revealed that NFATz and NFATx genes are in the same region.

Argifin, a new chitinase inhibitor, produced by Gliocladium sp. FTD-0668. II. Isolation, physico-chemical properties, and structure elucidation

A new chitinase inhibitor, named argifin, was isolated from the cultured broth of a fungal strain Gliocladium sp. FTD-0668. Argifin was purified from the cultured mycelium by the combination of cation exchange, anion exchange, adsorption, and gel filtration chromatographic methods. The structure of argifin was elucidated as cyclo(N(omega)-(N-methylcarbamoyl)-L-arginyl-N-methyl-L-phenylalan yl-beta-L-aspartyl-beta-L-aspartyl-D-alanyl) by NMR experiments and other spectroscopic analyses.

Chromatin remodeling and T helper subset differentiation

The T helper subsets Th1 and Th2 regulate specific types of immune responses by producing distinct sets of cytokines. Differentiation of the T helper subsets from their common precursors, naive CD4+ T cells, is induced by antigen stimulation and controlled by various other conditions. Of these conditions, the contributions of the cytokine environment have been the best characterized. The presence of interleukin-4 (IL-4) directs the differentiation towards Th2 cells, whereas IL-12 induces Thl differentiation. The Th2 signature cytokine genes encoding IL-4, IL-13, and IL-5 are clustered, and noncoding regions such as the intergenic region of the IL-4 and IL-13 genes are highly conserved from mice to humans. Alteration of the chromatin structure of this Th2 cytokine cluster region is detected as nuclease-accessible regions specific to Th2 cells. Activation of STAT6 promotes Th2 differentiation by inducing Th2-specific transcription factors, including GATA3. Expression of GATA3 induces Th2 differentiation and enhances the Th2 cell-specific chromatin accessibility, indicating that GATA3 is a key protein that regulates differentiation through chromatin remodeling. T helper subset differentiation provides a good system to study gene expression regulation at the chromatin level.

Argifin, a new chitinase inhibitor, produced by Gliocladium sp. FTD-0668. I. Taxonomy, fermentation, and biological activities

A new chitinase inhibitor, named argifin, was isolated from the cultured broth of a fungal strain FTD-0668. The strain was identified as Gliocladium sp. from morphological characteristics. The IC50 value of argifin against Lucilia cuprina chitinase was 3.7 microM. Argifin arrested the moult of cockroach larvae upon injection into the ventral abdominal part.

Successive expression and activation of NFAT family members during thymocyte differentiation

Differentiation of immature CD4(+)CD8(+) thymocytes to mature CD4(+) or CD8(+) T cells is induced by positive selection and appears to involve calcineurin-dependent activation of NFAT, a family of transcription factors. NFATx is predominantly expressed in CD4(+)CD8(+) thymocytes, whereas NFATp and NFATc are expressed at much lower levels in the thymus than in mature T cells. However, how or when each NFAT member is involved in the differentiation pathway is unclear. Using an in vitro model system where isolated CD4(+)CD8(+) thymocytes can survive and differentiate into semi-mature CD4-lineage T cells, we suggest that low calcineurin activity sustained for approximately 20 h is required for cell survival and differentiation. Accordingly, the DNA binding activity of NFAT slowly increased during the stimulation of 20 h to induce the differentiation. NFATx significantly contributed to the early rise, but the late increase was mostly due to NFATc activation. Meanwhile, the expression of NFATx mRNA decreased and that of NFATc mRNA increased. The DNA-binding activity of NFATp was detectable but low throughout the stimulation. NFATp became dominantly active after the semi-mature T cells differentiated into mature and activated CD4 T cells. These findings suggest that NFATx and NFATc successively play roles in T cell development.

Calcineurin is activated in rat hearts with physiological left ventricular hypertrophy induced by voluntary exercise training

BACKGROUND

Calcineurin may play a pivotal role in the signaling of cardiac hypertrophy; since this hypothesis was first put forward, controversial reports have been published using various experimental models. This study was designed to compare the physiological left ventricular hypertrophy (LVH) induced by voluntary exercise with LVH induced by aortic constriction and to determine whether calcineurin participates in the signaling of exercise-induced LVH.

METHODS AND RESULTS

Wistar rats were assigned to 1 of the following 5 groups: 10 weeks of voluntary exercise (EX), a sedentary regimen, a 1-week (AC1) or 4-week (AC4) ascending aortic constriction period, or a sham operation. EX rats ran 2.4+/-0.7 km/day voluntarily in specially manufactured cages; this was associated with an increase of LV diastolic dimension and stroke volume. Myocardial calcineurin activity markedly increased in EX rats (46.4+/-8.3 versus 18.4+/-0.5 pmol. min(-1). mg(-1) in sedentary rats; P<0.001) and in AC1 rats (44.9+/-6.7 versus 22.1+/-3.7 pmol. min(-1). mg(-1) in sham-operated rats; P<0.001), but not in AC4 rats (29.0+/-3.4 pmol. min(-1). mg(-1)). Treatment with cyclosporin A completely inhibited the development of LVH in EX rats, but it only partially attenuated the development of LVH in AC4 rats.

CONCLUSIONS

Calcineurin was activated in exercise-induced physiological LVH and in the developing phase of LVH (AC1), but not in decompensated pressure-overload hypertrophy (AC4). Cyclosporin therapy for the prevention of LVH may be harmful because it does not block the development of pathological hypertrophy but rather that of favorable adaptive hypertrophy.

[Long-term prognosis of asthmatic patients treated with low-dose beclomethasone dipropionate]

To clarify the prognosis of asthmatics treated with low-dose of inhaled beclomethasone dipropionate (BDP), we retrospectively assessed 43 patients treated with initial dose of 200 or 400 micrograms/day for 5 years, and obtained the following results. 1) 15 patients achieved step-down therapy (group A), 17 patients maintained initial dose of BDP (group B), and 11 patients required step-up therapy of BDP or daily use of oral prednisolone (group C). 2) There was no significant difference in age, sex, duration of disease, severity of disease, peripheral eosinophil counts, %FEV1 and histamine PC20 before BDP treatment among three groups. The percentage of atopic asthmatics was significantly higher in group C than in group A. 3) There was no significant difference in symptom and histamine PC20 between after 1 year state and after 5 years state in three groups. 4) After 1 year from the start of BDP treatment, only 18% patients got symptom free and neither patients exceeded 20,000 micrograms/ml of histamine PC20 in group C. Long-term treatment of low-dose BDP inhalation was effective on mild/moderate asthmatics. Patients requiring step-up therapy had not got sufficient improvement in bronchial hyperresponsiveness after one-year treatment.

Estrogen receptor beta mRNA in colon cancer cells: growth effects of estrogen and genistein

Knowledge regarding the expression of the recently cloned estrogen receptor beta (ERbeta) in colonic mucosa is limited. In this study, we demonstrated that five human colon cancer cell lines, HT29, Colo320, Lovo, SW480, and HCT116, expressed ERbeta mRNA, but lacked ERalpha mRNA. Results from a cell growth assay demonstrated that these colon cancer cells were not influenced by estrogen, while genistein possessed slight growth inhibitory effects on HT29, Colo320 and Lovo cells at 10 microM, at which concentration is stimulated the growth of ERalpha-positive human breast cancer MCF-7 cells. Tamoxifen inhibited the growth of HT29 and Colo320 cells, dose-dependently, as well as MCF-7 cells. A transfected reporter plasmid containing a vitellogenin estrogen response element could be activated by estradiol in Colo320 cells. Taken together with previous reports, these data suggest that ERalpha and ERbeta may have different biological functions in colon cells.

[Rheumatoid arthritis-associated bronchiolitis successfully treated with erythromycin]

A 52-year-old man with a 4-year history of rheumatoid arthritis, and who had an episode of suspected BOOP in early 1994, was admitted to our hospital because of cough and fever. A chest X-ray film on admission showed small patchy infiltrates, and a computed tomographic (CT) scan showed centrilobular nodules and patchy infiltrates with thickened broncho-vascular bundles in both lungs. Transbronchial and thoracoscopic lung biopsies disclosed the coexistence of interstitial pneumonia with BOOP pattern, follicular bronchiolitis, and diffuse panbronchiolitis-like purulent and obliterative bronchiolitis. Due to findings of chronic sinusitis, the patient was treated with erythromycin for 8 weeks, and the abnormal CT shadows regressed. This was an interesting case of various pulmonary lesions associated with rheumatoid arthritis, and successfully treated with erythromycin.

Interleukin-18 in combination with IL-2 enhances natural killer cell activity without inducing large amounts of IFN-gamma in vivo

Interleukin-18 (IL-18) is known to synergistically enhance murine natural killer (NK) cell activity in vitro when combined with either IL-12 or IL-2. However, it has also been demonstrated that simultaneous administration of IL-18 and IL-12 to mice induces extraordinarily large amounts of interferon-gamma (IFN-gamma) in the serum. In this study, we examined the effects of a combination of IL-18 and IL-2 on in vivo NK cell activation in parallel with the induction of toxicity. In contrast to the IL-18 and IL-12 combination, the combined administration of IL-18 and IL-2 to BALB/c mice for 3 days induced neither high levels of IFN-gamma production nor other visible side effects. When compared with treatment with IL-18 or IL-2 alone, the combined treatment resulted in a significant increase in the number of DX-5 (pan-NK cells marker)-positive cells in spleens and a marked enhancement of splenic NK activity, as determined by standard cytotoxicity assays. Enhanced splenic cytotoxicity generated in the mice treated with both IL-18 and IL-2 was also observed against syngeneic Colon 26 adenocarcinoma cells. Consistent with this in vitro observation, combined treatment produced a significantly stronger inhibitory effect on the pulmonary metastases following i.v. injection of Colon 26 tumor cells than treatment with either cytokine alone. These results suggest that IL-18 combined with IL-2 potentiates in vivo NK cell activity and contributes to inhibition of tumor metastasis without inducing significant toxicity.

L-DOPA cyclohexyl ester is a novel potent and relatively stable competitive antagonist against L-DOPA among several L-DOPA ester compounds

We explored L-DOPA esters with chemically bulky structures to find a potent stable competitive antagonist against L-DOPA, compared to DOPA methyl ester (DOPA ME). In anesthetized rats, DOPA cyclohexyl ester (DOPA CHE), DOPA cyclopentyl ester (DOPA CPE) and DOPA cyclopentyldimethyl ester (DOPA CPDME) at 1 microgram microinjected into depressor sites of the nucleus tractus solitarii elicited or tended to elicit more marked antagonism against depressor responses to 60 ng L-DOPA, compared to DOPA ME. At 100 ng, DOPA CHE elicited the most potent antagonism. At 1 microgram, duration of the antagonistic activity of DOPA CHE was approximately three times longer than that of DOPA ME. During microdialysis of the nucleus accumbens, conversion from DOPA CHE at 1 microM perfused via probes to extracellular L-DOPA was the lowest among these compounds and less than one half of that from DOPA ME. Binding studies showed that the recognition site for L-DOPA differs from ionotropic glutamatergic, dopaminergic D1 and D2 receptors. We recently found that L-DOPA evoked by transient ischemia may act as a DOPA CHE-sensitive causal factor for glutamate release and resultant neuronal cell death. DOPA CHE is the most potent, relatively stable competitive antagonist against L-DOPA and is a useful mother compound to develop neuroprotective drugs.

Arisugacins C and D, novel acetylcholinesterase inhibitors and their related novel metabolites produced by Penicilium sp. FO-4259-11

The mutant of Penicillium sp. FO-4259, an arisugacins A and B producing strain, was found to produce a series of metabolites, designated arisugacins C, D, E, F, G and H, which were structurally related to arisugacins A and B. These compounds were isolated from the culture broth and the physico-chemical and biological properties were examined. The IC50 values of arisugacins C and D against acetylcholinesterase (AChE) were 2.5 microM and 3.5 microM, respectively. However arisugacins E, F, G and H did not inhibit AChE at 100 microM. Though they showed only weak or no activity against AChE compared with arisugacins A and B, they may be useful for the study of the structure-activity relationship.

Identification of cytochromes P450 involved in human liver microsomal metabolism of ecabapide, a prokinetic agent

1. In vitro studies identified the hepatic cytochrome P450 (CYP) enzyme(s) involved in the major metabolism of ecabapide in human. 2. Ecabapide mainly underwent N-dealkylation to form M1 and 6-hydroxylation of the benzamide moiety to form M6. 3. The rates of formation of the major metabolites M1 and M6 were significantly correlated with CYP3A-selective testosterone 6beta-hydroxylase activities in 14 different human liver microsomes. The formation of both metabolites was markedly decreased by ketoconazole, miconazole or troleandomycin (TAO), CYP3A-selective inhibitors, and also was inhibited by anti-CYP3A antibodies. 4. These results strongly indicate that CYP3A is the predominant isozyme responsible for the major metabolism of ecabapide in human liver microsomes. 5. Marginal inhibition of the formation of M1 and M6 by nifedipine, a substrate of CYP3A with a Ki > 100 microM, suggested that nifedipne has a limited potential to inhibit the major metabolic pathways of ecabapide.

Ectopic expression of activated Stat6 induces the expression of Th2-specific cytokines and transcription factors in developing Th1 cells

Stat6 is critical for IL-4-mediated Th2 cell development, but its molecular mechanism remains unclear. Here we constructed Stat6:ER, a Stat6-estrogen receptor fusion protein that can be activated by 4-hydroxy-tamoxifen, independently of IL-4 and endogenous Stat6. Retrovirus-mediated introduction of Stat6:ER into developing Th1 cells induced Th2-specific cytokines and suppressed IFNgamma production in a 4-HT-dependent manner and in the absence of IL-4. It also induced GATA-3 and c-maf expression and downregulated IL-12Rbeta2 chain expression. Its decreased ability to induce the Th2 phenotype with progressing Th1 cell commitment correlated with a decreased induction of GATA-3 and c-maf. This study indicates that Stat6 functions upstream of GATA-3 and c-Maf to induce Th2 development.

[A DOPA antagonist, DOPA cyclohexyl ester inhibits transient brain ischemia-induced release of glutamate and delayed neuronal cell death in striatal and hippocampal region of in vivo rats]

We have previously obtained evidence that DOPA is probably involved in an upstream process of mechanisms for in vivo neuronal cell death in striatum. We attempted to clarify whether or not this is also the case in hippocampal region of conscious Wistar rats. Four vessels were occluded for 5 min during microdialysis of hippocampus. DOPA, dopamine and glutamate (Glu) in perfusates collected every 10 min were measured by HPLC-ECD and spectrophotometer. Delayed neuronal cell death in hippocampus was evaluated 96 hr after ischemia. Five-min transient brain ischemia induced Glu release, with the peak being 2.5-fold of a basal release at the fraction immediately after ischemia. The release of DOPA and dopamine was not consistently detectable, but an increase was sometimes observed during and after ischemia. Delayed neuronal cell death was slight to moderate with 5-min ischemia. Intrastriatal perfusion of DOPA cyclohexyl ester (DOPA CHE) at 100 nM, a novel stable potent competitive DOPA antagonist, almost completely inhibited the ischemia-induced glutamate release, and protected hippocampal neurons from delayed cell death. Endogenously released DOPA itself seems to act on its recognition site and to behave as a causal and/or deteriorating factor on glutamate release and resultant delayed neuronal cell death by transient ischemia in rats.

Interictal hyperperfusion observed in infants with cortical dysgenesis

We investigated increases of interictal regional cerebral blood flow (rCBF) in patients with intractable epilepsy caused by cortical dysgenesis. Using single photon emission computed tomography, we measured interictal rCBF of epileptic foci in 24 patients with cortical dysgenesis who achieved Engel Class I or II outcomes at least 1 year after surgical intervention. The patients included 14 males and ten females, ranging in age from 2 months to 34 years (mean 6 years and 5 months). In the interictal period, dysplastic areas showed hyperperfusion in four patients (17%), hypoperfusion in 15 (62%), and isoperfusion patterns in five (21%). Interictal hyperperfusion was found in four infants aged 3-4 months; three with focal cortical dysplasia and one with hemimegalencephaly. Our results suggest that interictal hyperperfusion may indicate the presence of an active epileptic focus in infants with cortical dysgenesis, but not in older children or adults with the same disorder. Given the risk of misinterpreting the normal side as hypoperfused, the phenomenon of interictal hyperperfusion in the epileptogenic area should be taken into account when diagnosing pediatric epilepsy caused by cortical dysgenesis.

Meiotic contraction of CAG repeats in Saccharomyces cerevisiae

Several human neurodegenerative disorders are caused by expansion of CAG repeats that occurs during meiosis or gametogenesis. We anticipated that the CAG repeats cloned in a plasmid of Saccharomyces cerevisiae might undergo a change in the number of repeats during meiosis and sporulation. To test this possibility, we devised a new method to change in vitro the number of CAG repeats and constructed plasmids carrying (CAG)39, (CAG)65 or (CAG)123 from a plasmid carrying (CAG)18. We monitored the number of colonies showing an altered length of the repeat tracts during mitosis and meiotic growth. Contraction of long CAG repeat was found to occur frequently, whereas a few cases of expansion were observed. The contraction was equally enhanced in both orientations when the host cells grew through meiosis. Thus, our results suggest that long CAG repeats are destabilized during meiosis or gametogenesis in S. cerevisiae.

Cortical tubers without other stigmata of tuberous sclerosis: imaging and pathological findings

There is immense variability in the clinical presentation of tuberous sclerosis and many incomplete forms (formes frustes) exist. To investigate the imaging characteristics of cortical tubers seen in tuberous sclerosis unaccompanied by other stigmata, we reviewed MRI and CT of six patients who met the criteria for a definitive diagnosis of TS, established solely by the presence of a histologically confirmed cortical tuber. Five of the patients had a solitary cortical tuber and the last had three lesions, one of which was resected and confirmed histologically. The other two lesions were included in our study. CT showed five tubers as low density, but three were not identified. No calcified or dense lesions were observed. MRI revealed peripheral components and inner cores of seven cortical tubers in five patients, with differing signal characteristics. The subcortical cores, with T1 and T2 prolongation, were separated from the overlying cortex. Abnormal inhomogeneous high signal was observed in both the cortex and subcortical white matter on proton-density weighted or FLAIR images. A radially orientated white-matter band was observed in one patient, and central depression of the expanded gyri in another. In one patient, a cortical tuber was atypical, with a thick cortex on T1-weighted images and a blurred grey/white matter junction with diffusely increased signal on T2-weighted images. Cortical tubers without other stigmata of tuberous sclerosis are shown to be distinct from focal cortical dysplasia.

Syndrome of inappropriate secretion of antidiuretic hormone associated with amyotrophic lateral sclerosis in respiratory failure

A 65-year-old man who had muscle weakness and dysarthria was admitted for investigation of motor neuron disease. He had lost 12 kg of weight in 6 months. Neurological findings disclosed upper and lower motor neuron disturbances with normal sensory nerve function, and needle electromyography showed a neurogenic pattern. Laboratory findings on admission demonstrated dilutional hyponatraemia due to an excessive secretion of antidiuretic hormone (ADH). Based on these findings, the patient was diagnosed as having the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) associated with amyotrophic lateral sclerosis (ALS). During the night of first hospital day, the patient complained of severe dyspnoea, and mechanical ventilation was commenced. Following the mechanical ventilation, plasma ADH levels and serum sodium concentration were normalized. We propose that respiratory failure secondary to the atrophy of respiratory muscle might be responsible for the development of SIADH.

Enhanced epithelial cell turnover associated with p53 accumulation and high p21WAF1/CIP1 expression in ulcerative colitis

To cast light on accelerated epithelial cell turnover as an important risk factor of dysplasia and carcinoma development in patients with long-standing ulcerative colitis (UC), we examined cell proliferation and cell death, as well as expression of apoptosis-related markers, including p53 and p21WAF1/CIP1, in a series of cases. Biopsy specimens (n = 176; 84, active phase; 92, remission) were endoscopically obtained from 25 Japanese patients with UC. As controls, 68 biopsy specimens of normal mucosa were also examined from 27 Japanese patients with colon polyps. We counted the numbers of mitoses, apoptotic bodies, Ki-67-immunoreactive cells, and p21WAF1/CIP1-immunoreactive cells per 1000 crypt cells and the numbers of p53-positive cells per crypt. All of the indices in active UC were significantly higher than in either remitting UC cases or normal cases (mean mitotic index = 0.52, 0.28, and 0.15%, respectively; apoptotic index = 5.40, 2.91, and 1.30%, respectively; Ki-67 labeling index = 39.5, 28.3, and 26.8%, respectively; p21WAF1/CIP1 labeling index = 33.6, 20.0, and 19.0%, respectively; p53 labeling index = 0.66, 0.13, 0.13 per crypt, respectively). In addition, the mitotic, apoptotic, and Ki-67 labeling indices were increased in remitting UC of more than 10 years' duration, in comparison with those of less than 10 years' duration or the normal group. Immunostaining of serial sections revealed a small number of crypt cells coexpressing p53 and p21WAF1/CIP1. Increases in both epithelial cell proliferation and cell death, partially associated with p53 accumulation and high p21WAF1/CIP1 expression, are thus characteristic of active phase UC, as well as in remission of long-standing UC. Accelerated epithelial cell turnover caused by chronic inflammation and epithelial damage might predispose the mucosa to DNA damage, resulting in an elevated risk of mutation in line with dysplasia and carcinoma development in patients with UC.

Reactive oxygen intermediates stimulate interleukin-6 production in human bronchial epithelial cells

Reactive oxygen intermediates (ROIs) play an important role in the initiation and progression of lung diseases. In this study, we investigated whether ROIs were involved in the induction of interleukin (IL)-6 in human bronchial epithelial cells. We exposed normal human bronchial epithelial cells as well as a human bronchial epithelial cell line, HS-24, to ROIs. We measured the amount of IL-6 in the culture supernatants using ELISA and the IL-6 mRNA levels using RT-PCR. Superoxide anions (O-2), but not hydrogen peroxide (H2O2), increased IL-6 production. To examine whether it is a cell type-specific mechanism of airway epithelial cells, the experiments were also performed in human lung fibroblasts, WI-38-40. In WI-38-40 cells, neither O-2 nor H2O2 increased IL-6 production. In contrast, tumor necrosis factor (TNF)-alpha (200 U/ml) induced IL-6 at the protein and mRNA levels in both airway epithelial cells and lung fibroblasts. This cytokine-induced IL-6 production was significantly suppressed by several antioxidants, including dimethyl sulfoxide (DMSO), in airway epithelial cells. In WI-38-40 cells, DMSO was not able to suppress IL-6 production induced by TNF-alpha. Pretreatment with DMSO recovered the TNF-alpha-induced depletion of intracellular reduced glutathione in HS-24 cells. These findings indicate that oxidant stress specifically induces IL-6 production in human bronchial epithelial cells and that in these cells ROIs may be involved in IL-6 production after stimulation with cytokines such as TNF-alpha. Presumably, ROIs participate in the local immune response in lung diseases via IL-6 release from bronchial epithelial cells.