A case of adult-onset Still's disease complicated by non-Hodgkin's lymphoma

Left cervical lymphadenopathy developed in a 50-year-old male who had a history of adult-onset Still's disease for the preceding 18 months. Still's disease is characterized by rash, fever, and leukocytosis. Lymphadenopathy has been reported in about 60% of the patients, and most histopathologic studies have shown non-specific reactive hyperplasia. However, in this case, an open biopsy of the cervical node revealed a histology of diffuse large B-cell lymphoma. The B-cell malignant lymphoma that developed may have resulted from a sequential progression of a previous stage of benign lymphoproliferative lesion. Our case suggests that the pathophysiology of adult-onset Still's disease involves the stimulation of lymphoid systems to the point of progression towards lymphoma. Malignant lymphoma should be added to the list of life-threatening complications which, although rare, are associated with this disease.

Exogenous PML/RARα Fusion Gene Responds to All-trans Retinoic Acid Results in Differentiation of the Human B Cell Line

The interaction of an exogenous PML/RARα fusion gene, associated with acute promyelocytic leukemia, with all-trans retinoic acid (ATRA) was examined in B-lymphoid cell lines. RPMI8866 cells were transfected with PML/RARα cDNA in the expression vector pGD and two stable transformants (RPMI8866Y-4 and RPMI8866Y-17) were established by selection with G418. ATRA inhibited the growth of those stable transformants, as assessed by [(3)H]-thymidine incorporation, but had no effect on the growth of control cells stably transformed with neomycin resistant gene alone. ATRA also increased expression of CD38 and immunoglobulin production in RPMI8866Y-4 cells but not in control cells. When these results are taken together, it can be observed that the exogenous PML/RARα fusion gene responds to ATRA, which results in cell differentiation of the human B cell line.

Establishment of a myeloid cell line, YM711, characterized by retinoid resistance

A myeloid cell line (YM711) was established by transfecting exogenous PML/RARalpha cDNA into peripheral blood stem cells. The cells were positive for CD33, CD34, CD38, CD13, CD14, and CD11b. Cytochemical examination revealed YM711 cells to be positive for peroxidase, alpha-naphtyl butyrate esterase, and acid phosphatase as well. Karyotypic analysis showed them to be nearly tetraploid (92 XXYY). Reverse-transcription polymerase chain reaction showed that, although PML/RARalpha mRNA was detected in YM711, these cells could not be differentiated by all-trans retinoic acid (ATRA). We therefore designated the YM711 cell line as being ATRA resistant. Because YM711 expressed multi drug resistance 1 (MDR-1) mRNA and p-glycoprotein cell surface protein, we assessed whether verapamil and ATRA would induce the differentiation of YM711 cells; they did not. An increased expression of cellular retinoic acid-binding protein (CRABP)-II was also detected on YM711 cells compared with that of HL-60. These results suggest that high level of expression of CRABP-II may contribute to be the mechanism of ATRA resistance. This cell line may be useful in evaluating the mechanism of resistance to retinoid.

Transient eosinophilia by HIV infection

We describe a case of early human immunodeficiency virus infection characterized by transient eosinophilia without an elevated immunoglobulin E concentration, allergic symptoms, or atopic dermatitis. Possible mechanisms of the eosinophilia are discussed.

Identification of thioredoxin-binding protein-2/vitamin D(3) up-regulated protein 1 as a negative regulator of thioredoxin function and expression

Recent works have shown the importance of reduction/oxidation (redox) regulation in various biological phenomena. Thioredoxin (TRX) is one of the major components of the thiol reducing system and plays multiple roles in cellular processes such as proliferation, apoptosis, and gene expression. To investigate the molecular mechanism of TRX action, we used a yeast two-hybrid system to identify TRX-binding proteins. One of the candidates, designated as thioredoxin-binding protein-2 (TBP-2), was identical to vitamin D(3) up-regulated protein 1 (VDUP1). The association of TRX with TBP-2/VDUP1 was observed in vitro and in vivo. TBP-2/VDUP1 bound to reduced TRX but not to oxidized TRX nor to mutant TRX, in which two redox active cysteine residues are substituted by serine. Thus, the catalytic center of TRX seems to be important for the interaction. Insulin reducing activity of TRX was inhibited by the addition of recombinant TBP-2/VDUP1 protein in vitro. In COS-7 and HEK293 cells transiently transfected with TBP-2/VDUP1 expression vector, decrease of insulin reducing activity of TRX and diminishment of TRX expression was observed. These results suggested that TBP-2/VDUP1 serves as a negative regulator of the biological function and expression of TRX. Treatment of HL-60 cells with 1alpha, 25-dihydroxyvitamin D(3) caused an increase of TBP-2/VDUP1 expression and down-regulation of the expression and the reducing activity of TRX. Therefore, the TRX-TBP-2/VDUP1 interaction may be an important redox regulatory mechanism in cellular processes, including differentiation of myeloid and macrophage lineages.

Overexpression of thioredoxin in transgenic mice attenuates focal ischemic brain damage

Thioredoxin (TRX) plays important biological roles both in intra- and extracellular compartments, including in regulation of various intracellular molecules via thiol redox control. We produced TRX overexpressing mice and confirmed that there were no anatomical and physiological differences between wild-type (WT) mice and TRX transgenic (Tg) mice. In the present study we subjected mice to focal brain ischemia to shed light on the role of TRX in brain ischemic injury. At 24 hr after middle cerebral artery occlusion, infarct areas and volume were significantly smaller in Tg mice than in WT mice. Moreover neurological deficit was ameliorated in Tg mice compared with WT mice. Protein carbonyl content, a marker of cellular protein oxidation, in Tg mice showed less increase than did that of WT mice after the ischemic insult. Furthermore, c-fos expression in Tg mice was stronger than in WT mice 1 hr after ischemia. Our results suggest that transgene expression of TRX decreased ischemic neuronal injury and that TRX and the redox state modified by TRX play a crucial role in brain damage during stroke.

Redox control of Epstein-Barr virus replication by human thioredoxin/ATL-derived factor: differential regulation of lytic and latent infection

Human thioredoxin (hTRX)/adult T-cell leukemia (ATL)-derived factor (ADF) was originally reported as an interleukin-2 (IL-2) receptor-alpha-inducing factor produced by human T-cell lymphotropic virus-1-positive (HTLV-1+) cell lines. Growing evidence indicates that hTRX/ADF plays important roles in cellular responses against oxidative stress and is involved in a variety of cellular functions. A high level of hTRX/ADF expression is also observed in other human virus-infected cell lines including those of Epstein-Barr virus (EBV) and human papillomavirus. In this report, we analyzed the effect of hTRX/ADF on lytic amplification and persistent replication of EBV as a model for lytic versus latent phase of viral replication in host cells. Addition of hTRX/ADF clearly suppressed lytic replication of EBV in Raji cells and B95-8 cells induced to the lytic phase of 12-O-tetradecanoylphorbol-13-acetate (TPA), and it prevented the death of these cells evoked by the lytic induction. In contrast, hTRX/ADF did not have any effect on persistent replication in the latent phase. These data indicated that hTRX/ADF prevents EBV-transformed cells from proceeding into the lytic phase and regulates cohabitation of EBV and its host cells.

Expression of thioredoxin is enhanced in atherosclerotic plaques and during neointima formation in rat arteries

Thioredoxin (TRX) is an intracellular enzyme that has a variety of activities as a hydrogen donor for various intracellular molecules. In the present study, we investigated the role of TRX in atherosclerotic lesions. In human atherosclerotic specimens, TRX and TRX mRNA were enhanced in endothelial cells and macrophages in the atherosclerotic plaques. In balloon-injured rat arteries, TRX expression increased from 2 to 6 weeks after injury; TRX was induced in the neointimal regenerating endothelial cells. In hybridization experiments, TRX mRNA was also induced from 2 to 6 weeks in the endothelium. In this model, inducible nitric oxide synthase immunoreactivity in the neointimal smooth muscle cells and endothelial cells increased from 2 to 6 weeks after surgical procedures were performed. During this period, the immunoreactivity of nitrotyrosine, which is a marker of nitric oxide (NO) production, also increased. We focused on the association between TRX and NO. In vitro studies using a murine endothelial cell line showed TRX and TRX mRNA induction by NO and peroxynitrite donors. Enhanced expression of TRX was detected mainly within the cytoplasm in immunocytochemical studies. In addition, TRX-transfected cells showed resistance to peroxynitrite-induced cytotoxicity. These findings indicate that TRX and the cellular redox state modified by TRX play a crucial role in arterial neointima formation in atherosclerosis.

Thiol compounds rescue growth inhibition by retinoic acid on HTLV-I (+) T lymphocytes; possible mechanism of retinoic-acid-induced growth inhibition of adult T-cell leukemia cells

We demonstrated significant growth inhibition by retinoic acid (RA) of HTLV-I (+) T-cell lines (ATL-2 and HUT102), but not HTLV-I (-) T-cell lines (MOLT-4 and Jurkat). We hypothesized that the mechanism of growth inhibition by RA depends on an imbalance in redox potential. To examine the effect of exogenous thiol compounds for the growth of HTLV-I (+) T-cell lines by RA, HTLV-I (+) T-cell lines were cultured with several thiol compounds (thioredoxin, L-cystine, and GSH), following addition of 13-cis RA or ATRA, respectively, in cultured with thiol free medium. Unexpectedly, thiol compounds alone did not restore growth inhibition of HTLV-I (+) T-cell lines. However, when those cells were preincubated with thiol compounds for 24 hours, no growth inhibition by 13-cis RA or ATRA was observed. These results suggest that thiol compounds are associated strongly with sensitivity to RA of HTLV-I (+) T cells, but not of HTLV-I (-) T cells and that thiol compounds serve an important role on HTLV-I (+) T cells.

Inhibition of protein kinase C-mediated CD4 down-regulation by oxidative stress in T lymphocytes

The CD4 molecule acts as a receptor for class II MHC molecules to stabilize Ag recognition by the TCR and as a high affinity receptor for HIV-1. In this study, we investigated the effect of oxidative stress on the level of CD4 expression on cultured peripheral blood T lymphocytes (PBL blasts). As previously reported, we observed that the surface CD4 was down-regulated by PMA. Unexpectedly, treatment of PBL blasts with hydrogen peroxide (H2O2) or a sulfhydryl oxidative reagent, diamide, almost completely inhibited PMA-induced CD4 down-regulation, although these oxidants per se did not affect the level of CD4 expression. We next assessed the serine phosphorylation of CD4, which is reported to be an indispensable process for PMA-induced CD4 endocytosis. PMA could induce the serine phosphorylation even in the presence of oxidants. We also found that these oxidants had an additive effect on PMA-induced dissociation between CD4 and p56(lck), which is known to be another necessary step for CD4 endocytosis. These results indicate that in T cells, oxidants inhibit protein kinase C-mediated CD4 down-regulation due to perturbing a signaling process other than the above two steps, implying that oxidative stress may tune the functions of CD4+ T cells and their susceptibility to HIV-1 through the control of CD4 expression.

Inhibition of protein kinase C-mediated CD4 down-regulation by oxidative stress in T lymphocytes

The CD4 molecule acts as a receptor for class II MHC molecules to stabilize Ag recognition by the TCR and as a high affinity receptor for HIV-1. In this study, we investigated the effect of oxidative stress on the level of CD4 expression on cultured peripheral blood T lymphocytes (PBL blasts). As previously reported, we observed that the surface CD4 was down-regulated by PMA. Unexpectedly, treatment of PBL blasts with hydrogen peroxide (H2O2) or a sulfhydryl oxidative reagent, diamide, almost completely inhibited PMA-induced CD4 down-regulation, although these oxidants per se did not affect the level of CD4 expression. We next assessed the serine phosphorylation of CD4, which is reported to be an indispensable process for PMA-induced CD4 endocytosis. PMA could induce the serine phosphorylation even in the presence of oxidants. We also found that these oxidants had an additive effect on PMA-induced dissociation between CD4 and p56(lck), which is known to be another necessary step for CD4 endocytosis. These results indicate that in T cells, oxidants inhibit protein kinase C-mediated CD4 down-regulation due to perturbing a signaling process other than the above two steps, implying that oxidative stress may tune the functions of CD4+ T cells and their susceptibility to HIV-1 through the control of CD4 expression.

Transactivation of an inducible anti-oxidative stress protein, human thioredoxin by HTLV-I Tax

Adult T-cell leukemia derived factor (ADF)/human thioredoxin (TRX), which has thiol reducing and radical scavenging activities, plays an essential role on cellular protection against oxidative stress and cell death. TRX itself is induced by various oxidative stress as well as the Human T-cell lymphotropic virus type I (HTLV-I) Tax protein. To investigate the mechanism of this induction, the promoter region of the TRX gene was analyzed. Chloramphenicol acetyltransferase (CAT) reporter constructs containing the TRX promoter sequences responded to the overexpression of the Tax protein, whereas various oxidative agents activated the TRX promoter through a newly identified oxidative responsive element. Moreover, TRX was translocated from the cytoplasm into the nucleus by ultraviolet irradiation, suggesting its possible role on sensing and transducing oxidative signals.

Inhibition of growth and induction of apoptosis by all-trans retinoic acid in lymphoid cell lines transfected with the PML/RAR alpha fusion gene

The interaction of an exogenous PML/RAR alpha fusion gene associated with acute promyelocytic leukaemia, with all-trans retinoic acid (ATRA) was examined in two lymphoid cell lines. L1210 and MOLT-4 cells were transfected with PML/RAR alpha cDNA in the expression vector pGD and stable transformants (L1210PML/RAR alpha and MOLT-4PML/RAR alpha) were selected with G418. ATRA inhibited the growth of these stable transformants, as assessed by [3H]thymidine incorporation, in a dose-dependent manner, but had no effect on the growth of control cells stably transformed with neomycin resistant gene alone. ATRA also induced apoptosis, as assessed by fragmentation of genomic DNA, in L121OPML/RAR alpha and MOLT-4PML/RAR alpha cells but not in control cells. The exogenous PML/RAR alpha fusion gene therefore probably mediates the effects of ATRA on cell growth and apoptosis in these cell lines.

13-cis retinoic acid inhibits growth of adult T cell leukemia cells and causes apoptosis; possible new indication for retinoid therapy

We evaluated the effects of 13-cis retinoic acid (13-cis RA) on the growth of peripheral blood mononuclear cells (PBMC) obtained from 12 patients with adult T cell leukemia (ATL). In general, 13-cis RA potently inhibited the growth of PBMC from ATL patients. However, the sensitivity of the cells to 13-cis RA-induced growth inhibition varied among the patients. The ATL patients fell into three groups (hypersensitive, sensitive and resistant to 13-cis RA) according to the percent reduction of 3H-thymidine incorporation before and after treatment with 13-cis RA. Agarose gel electrophoresis of total genomic DNA from a patient sensitive to 13-cis RA provided evidence of the DNA fragmentation indicative of apoptosis. The ability of 13-cis RA to induce apoptosis in PBMC from ATL patients suggests that retinoids may be useful in the treatment of ATL.

Purification and characterization of cytochrome P-45014DM (lanosterol 14 alpha-demethylase) from pig liver microsomes

Cytochrome P-45014DM, which catalyzes lanosterol 14 alpha-demethylation, from pig liver microsomes was purified to a state of virtually homogeneous by gel electrophoresis. Its apparent monomeric molecular weight was estimated to be 53,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the amino-terminal amino acid sequence was Gly-Leu-Leu-Thr-Gly(Leu)-Asp-Leu-Leu-Gly-Ile. When reconstituted with NADPH-cytochrome P-450-reductase, the enzyme showed a high activity for lanosterol and 24,25-dihydrolanosterol 14 alpha-demethylation. Furthermore, the oxygenated intermediates of 24,25-dihydrolanosterol 14 alpha-demethylation, 32-hydroxy-24,25-dihydrolanosterol and 32-oxo-24,25-dihydrolanosterol, were converted to the 32-nor compound, 4,4-dimethylcholesta-8,14-dien-3 beta-ol, by the reconstituted enzyme system.

Visualization of ANP receptor on glomeruli of bovine kidney by use of a specific antiserum

Atrial natriuretic peptide (ANP) receptor was purified from the bovine lung by affinity chromatography and preparative gel electrophoresis. A specific antiserum was raised against the purified receptor and used to localize receptors immunohistochemically on bovine kidney sections. Intense staining was seen in glomeruli. This distribution corresponds to that of ANP binding sites revealed by previous autoradiographic analyses and matches a glomerular action of ANP suggested by physiological studies.