An approach to identify new genes in autoimmune diseases: lessons from rheumatoid arthritis

We have searched the human genome for genes that predispose to rheumatoid arthritis using fluorescence-based microsatellite marker analysis and affected sib-pair linkage studies. A panel of 41 Japanese families, each with at least two affected siblings, was typed for genome-wide 358 polymorphic microsatellite marker loci. Three principal chromosome regions of linkage, D1S253/214, D8S556 and DX1232, have been assigned, which we call RA1, RA2 and RA3 for rheumatoid arthritis disease loci. We are now assigning the death receptor 3 as a candidate gene for RA1, and the truncated form of Dbl proto-oncogene, which does not contain the 23rd and 24th exons, as disease gene for RA3. Microsatellite marker analyses seem to be promising and new genes are now being identified by reference to sequence tag sites.

Transforming growth factor-beta1 expression in early biopsy specimen predicts long-term graft function following pediatric renal transplantation

The main cause of late graft loss or declining long-term graft function is chronic allograft nephropathy (CAN), characterized by progressive interstitial fibrosis. Transforming growth factor (TGF)-beta1 plays a key role in fibrogenesis. We immunohistochemically investigated whether the degree of TGF-beta1 expression in early biopsy specimens routinely obtained from stable allografts at 100 d could predict fibrosis and graft dysfunction in the late phase. Patients were children with grafts from related donors. We immunohistochemically determined intracellular and extracellular expression of TGF-beta1 in the graft using LC antibody (LC) for intracellular TGF-beta1 and CC antibody (CC) for extracellular TGF-beta1. The change in creatinine clearance between 100 d and 3 yr after transplantation (DeltaCcr) was used as an index of long-term graft function. We also used image analysis to calculate the relative area involved by interstitial fibrosis in the trichrome-stained section of graft biopsy specimens at 100 d and 3 yr, designating the change as DeltaFI. DeltaCcr was -4.2+/-9.4 mL/min in subjects with minimal early immunoreactivity for CC and -20.5+/-15.9 mL/min in subjects with strong reactivity (p<0.05). DeltaCcr was -14.5+/-18.6 mL/min in subjects with minimal early immunoreactivity for LC and -11.7+/-12.8 mL/min in those with strong reactivity. DeltaFI in subjects with minimal CC reactivity (1.28+/-4.11%) tended to be lower than that in subjects with strong reactivity (8.45+/-15.47%). Neither fibrosis at 100 d nor DeltaFI differed between subjects with minimal and strong LC reactivity. Thus, strong extracellular TGF-beta1 expression in grafts at 100 d after transplantation is associated with a long-term decline in graft function and tends to be associated with increased graft fibrosis at 3 yr.

Direct catalytic enantio- and diastereoselective aldol reaction using a Zn-Zn-linked-BINOL complex: a practical synthesis of syn-1,2-diols

[reaction: see text] The direct catalytic enantio- and diastereoselective aldol reaction with 2-hydroxy-2'-methoxyacetophenone proceeded smoothly using as little as 1 mol % of a dinuclear zinc catalyst, Zn-Zn-linked-BINOL complex 2, to afford alpha,beta-dihydroxy ketones in a highly syn-selective manner (up to syn/anti 97/3) and in excellent yields (up to 95%) and ees (up to 99%). Efficient transformations of the alpha,beta-dihydroxy ketone into an alpha,beta-dihydroxy ester and an alpha,beta-dihydroxy amide via regioselective rearrangements are also described.

Localized activation of m-calpain in migrating human umbilical vein endothelial cells stimulated by shear stress

Using a parallel-plate flow-chamber and confocal laser scanning microscopy (CLSM), we studied the mode of cytoskeletal reorganization in migrating HUVECs stimulated by shear stress. Activation of m-calpain associated with a change in the spatial distribution of cytoplasmic ionized Ca2+ concentration ([Ca2+](i)) was studied. Shear stress (10 dyne/cm(2)) caused migration and decrease in the F-actin content of HUVECs. Migrating individual HUVECs showed the lamellipodium formed in the direction of cell migration, in which [Ca2+](i) elevated to 148 +/- 12 nM in a localized fashion. We found the appearance of activated m-calpain in the local area of the migrating HUVECs, which was associated with a decrease in the amounts of pp125FAK and ezrin. The localized rise in [Ca2+](i) might be closely related to morphological change to regulate the direction of cell migration induced by shear stress through localized activation of m-calpain.

Pathophysiology and treatment of IgA nephropathy in children

IgA nephropathy is the most-common primary glomerulonephritis worldwide, and about 20%-50% of patients develop progressive renal failure. The pathogenesis is still unknown and treatment has not yet been established. Knowledge concerning childhood IgA nephropathy has expanded greatly in the last 10 years, and its importance as the major form of glomerulonephritis and major contributor to end-stage renal disease is also becoming apparent in children. This review focuses on the pathophysiology and treatment of IgA nephropathy in children.

Polymorphisms of renin-angiotensin system genes in childhood IgA nephropathy

We investigated whether polymorphisms of the renin-angiotensin system genes are involved in IgA nephropathy in Japanese children. We identified the M235T polymorphism of the angiotensinogen (AGT) gene, the I/D polymorphisms of the angiotensin-converting enzyme (ACE) gene, and the A1166C polymorphism of the angiotensin II type 1 receptor gene in 95 Japanese children with IgA nephropathy and 99 healthy Japanese adults. There were no differences in the genotype and allele frequencies of these genes between patients with IgA nephropathy and controls. Urinary protein excretion at the time of biopsy was significantly greater in patients with the TT genotype of the AGT gene than in those with the MM/MT genotypes of the AGT gene (1.32 +/- 1.42 versus 0.75 +/- 0.78 g/day; P = 0.01) and in patients with the ID/DD genotypes of the ACE gene than in those with the II genotype of the ACE gene (1.45 +/- 1.50 versus 0.63 +/- 0.56 g/day; P = 0.001). Thus, the TT genotype of the AGT gene and the ID/DD genotype of the ACE gene are associated with increased severity of proteinuria, suggesting that AGT and ACE gene polymorphisms may play a significant role in the progression of IgA nephropathy in Japanese children.

Redox regulation of the nuclear receptor

Redox regulation is currently considered a mode of signal transduction for coordinated regulation of a variety of cellular processes. Transcriptional regulation of gene expression is also influenced by the cellular redox state, for example, through the oxidoreductive modification of transcription factors. The nuclear receptors act as ligand-dependent transcription factors and are considered to be one of the key regulators of essential biological processes. Using a glucocorticoid receptor as a model, we show that redox regulation of receptor function is one of the dynamic cellular responses to environmental stimuli.

Thrombin stimulates cell proliferation in human fibroblast-like synoviocytes in nuclear factor-kappaB activation and protein kinase C mediated pathway

OBJECTIVE

To examine the effect of thrombin on nuclear factor (NF)-kappaB activation and cell proliferation in synovial cells from patients with rheumatoid arthritis (RA).

METHODS

Using cultured human synovial cells from patients with RA, electrophoretic mobility shift assay, [3H]thymidine incorporation assay, and MTT assay were performed. We tested the upregulatory effects of thrombin on NF-kappaB activation and cell proliferation. The effect of thrombin on degradation of IkappaB was analyzed by Western blot.

RESULTS

Thrombin transiently induced DNA-binding activity of NF-kappaB, followed by degradation of IkappaBalpha, but not IkappaBbeta1. Moreover, synovial cell proliferation was stimulated by thrombin in a dose dependent manner. The kinetics of synovial cell proliferation induced by thrombin were almost parallel to those of NF-kappaB activation. Supershift analysis revealed that thrombin induced DNA-binding complexes were made up principally of the p65 and p50 Rel family members. Further, protein kinase C inhibitor calphostin C repressed thrombin induced NF-kappaB activation and cell proliferation in synovial cells.

CONCLUSION

Thrombin stimulates synovial cell proliferation involved in NF-kappaB activation, at least in part, through a protein kinase C mediated pathway, possibly indicating that thrombin plays an important role in synovial hyperplasia in RA.

Fringe pattern correlator for three-dimensional object recognition

We propose a novel three-dimensional (3-D) object-recognition method based on a Fourier-transform profilometry technique and a two-dimensional (2-D) correlation technique. Height information on 3-D objects is transformed to phase information on 2-D complex amplitude by use of the Fourier-transform profilometry technique. 3-D objects are recognized using correlation by use of the transformed complex amplitude.

Functional modulation of the mineralocorticoid receptor by cis-diamminedichloroplatinum (II)

BACKGROUND

Renal salt wasting and hypotension are some of the frequent complications in patients treated with cis-diamminedichloroplatinum (II) (cDDP), and it is suggested that cDDP produces an abnormality in the renin-angiotensin system. However, not only the underlying mechanism but also prophylactic treatment of this cDDP toxicity remains unknown. In the present study, we investigated the molecular mechanism of this cDDP-induced disturbance of renal sodium handling with focusing on the effect of cDDP on mineralocorticoid receptor (MR) function.

METHODS

The effect of cDDP was studied on nuclear translocation, DNA binding activity, and transactivation function of the MR.

RESULTS

In a transient transfection assay, cDDP suppressed MR-dependent reporter gene expression. This cDDP-mediated repression of MR function, at least in part, is suggested to be due to the generation of reactive oxygen species and a subsequent decrease in ligand-dependent nuclear translocation and suppression of the interaction with DNA of the MR. This redox-dependent repression of MR function both in vitro and in vivo was reversed by treatment with reducing reagents. Moreover, cDDP, most possibly via formation of DNA adducts, inhibited MR-DNA interaction in a redox-independent fashion.

CONCLUSIONS

MR function is impaired by cDDP at multiple levels, via redox-dependent and -independent mechanisms.

Hair-discoloration of Japanese elite swimmers

To understand hair-discoloration in relation to swimming, we examined sixty-seven elite swimmers of the Japan National Swimming Team and fifty-four, age-matched subjects as controls. The incidence of hair discoloration (61%) in the swimmers' group was significantly higher than that in controls (0%) (p<0.0001). Interestingly, surface damage of the nail plates coexisted in the swimmers with the scalp-hair discoloration. The hairs picked from the eight swimmers and two age-matched individuals as controls were examined by electron microscope (EM) and EM X-ray microanalyzer. The swimmers' discolored, golden hair revealed complete disappearance of hair cuticle both by scanning EM (SEM) and transmission EM (TEM). The quantity of melanosomes in the cortex decreased, and their diameter was smaller than that of controls. In addition, irregularly shaped melanosomes with variable electron density and less electron-dense melanosomes with white haloes were frequently observed in the swimmers' golden hair. The X-ray elemental spectrograph by SEM revealed that the content of sulfur in all the swimmers' discoloured hair was lower than that in the normal controls and that the content of chlorine in the male swimmers' discoloured hair was higher than that in the female swimmers and the normal controls. The X-ray elemental microanalysis by TEM focused on melanosomes in the cortex of the cross section and detected elemental chlorine in all swimmers' golden hairs. It did not detect any element in the control hairs. The 14C-tyrosine uptake test of hairbulbs found no significant difference between the swimmers and the normal controls. These findings suggest that hair discoloration was mainly due to cuticle damage by friction with water. Hypochlorous acid in the swimming pool water can penetrate to the hair cortex through the cuticle. It can oxidize and degenerate melanosomes there.

Acute tubulointerstitial nephritis in 21 Japanese children

PATIENTS AND METHODS

We studied 21 Japanese children aged 1.2 to 14.9 years with biopsy-proven acute tubulointerstitial nephritis (ATIN; 5 drug-induced, 7 infection-related, 3 tubulointerstitial nephritis and uveitis syndrome (TINU), and 6 unclassified) for clinical presentation, laboratory findings, and outcome to clarify the clinical features of the entity. All developed acute renal failure with peak BUN values from 25 to 164 mg/dl (mean 83 mg/dl) and peak serum creatinine values from 1.5 to 15.1 mg/dl (mean 6.5 mg/dl). All the 7 infection-related ATIN were associated with Yersinia pseudotuberculosis infection. Four of the 21 patients underwent dialysis therapy for anuria and 1 patient in the unclassified ATIN showed progression to chronic renal failure.

RESULTS

In 20 patients, renal insufficiency lasted for 6 to 73 days: 5 drug-induced; median and ranges 25 (12-33) days, 7 infection-related; 15 (6-22) days, 3 TINU; 65 (55-73) days, and 5 unclassified; 24 (6-34) days. Oral steroid therapy was introduced to the 3 TINU patients because of the prolonged renal dysfunction. Although it was effective in all, 2 of them showed a deterioration of clinical symptoms or renal function after reducing the dosage of steroid.

CONCLUSION

Consequently, TINU patients required a longer period of time for the improvement of renal function compared to the other etiologies.

The RING finger protein SNURF modulates nuclear trafficking of the androgen receptor

The androgen receptor (AR) is a transcription factor that mediates androgen action. We have used the green fluorescent protein (GFP) technique to investigate dynamics of nuclear trafficking of human AR in living cells. In the absence of ligand, the GFP-AR fusion protein is distributed between cytoplasm and nuclei. Androgen exposure leads to a rapid and complete import of GFP-AR to nuclei of CV-1 cells (&gt;=90% nuclear in 30 minutes), whereas a pure antiandrogen, Casodex, elicits a slower (&lt;40% nuclear in 30 minutes) and incomplete transfer. Unliganded ARs with mutations in the basic amino acids of the bipartite nuclear localization signal (NLS) within the second zinc finger and the hinge region are predominantly cytoplasmic and their androgen-dependent nuclear import is severely compromised ((3/4)20% nuclear in 30 minutes). Interestingly, substitutions of the Leu residues flanking the bipartite NLS lead to inefficient nuclear transfer in response to androgen ((3/4)20% nuclear in 30 minutes). The ligand-binding domain of AR, which represses bipartite NLS activity, contains an agonist-specific NLS. The small nuclear RING finger protein SNURF, which interacts with AR through a region overlapping with the bipartite NLS, facilitates AR import to nuclei and retards its export on hormone withdrawal. More AR is associated with the nuclear matrix in the presence than absence of coexpressed SNURF. We suggest that the SNURF-mediated tethering of AR in nuclei represents a novel mechanism for activating steroid receptor functions.

Spontaneous and cytokine regulated c-fos gene expression in rheumatoid synovial cells: resistance to cytokine stimulation when the c-fos gene is overexpressed

OBJECTIVE

To study the effect of cytokines on the transactivation of the c-fos gene in relation to the contribution of overexpression of c-fos/AP-1 in rheumatoid joint destruction.

METHODS

The promoter region (-447 to +109) of the human c-fos gene was integrated upstream of the chloramphenicol acetyltransferase (CAT) reporter gene, and the effect of cytokines on the expression of the c-fos gene was studied in the rheumatoid synovial cells of early (3-4) or late (14-18) passages, in the presence or absence of cytokines, by the transient transfection assay.

RESULTS

Expression of c-fos gene was enhanced by tumour necrosis factor alpha (TNF alpha) and interleukin 6 (IL6) in the synovial cells of early passage, whereas it was not enhanced in the synovial cells of late passage. The c-fos gene expression was also enhanced by 13-O-tetradecanoyl phorbol-13-acetate (TPA) in early passage but was somewhat suppressed in the late passage. It was found that the c-fos gene and c-Fos protein were both increased in the synovial cells of late passage. Similarly, c-fos gene expression was also not increased by TPA or cytokine stimulation in the stable c-fos transformants (fos-pH8) or H-ras transformed NIH3T3 cells (NIH H-ras cells) that constitutively expressed c-fos genes.

CONCLUSIONS

Although TNF alpha and IL6 augmented c-fos gene expression of rheumatoid synovial cells, transactivation of c-fos gene became resistant against cytokine stimulation under prolonged expression of c-fos gene, which may impart a tumour-like characteristic to rheumatoid synovial cells.

A multicenter trial of mizoribine compared with placebo in children with frequently relapsing nephrotic syndrome

BACKGROUND

The use of corticosteroids or cytotoxic/immunosuppressive agents such as cyclophosphamide, chlorambucil, and cyclosporine for the treatment of frequently relapsing nephrotic syndrome (FRNS) is limited because of their adverse effects. This study was conducted to evaluate the efficacy and safety of mizoribine, a relatively new immunosuppressive drug developed in Japan, in children with FRNS.

METHODS

A double-blind, placebo-controlled, multicenter trial was carried out in children, from 2 to 19 years old, with FRNS. At relapse, patients were treated with prednisolone. According to a dynamic allocation, mizoribine or a placebo was concurrently administered to each patient. Prednisolone was gradually tapered and discontinued within 12 weeks. The test drug was maintained for 48 weeks. The primary end point was the relapse rate (the total number of relapses/the total treatment days for all patients). Analyses were performed according to the intention-to-treat principle.

RESULTS

The primary analysis was conducted on 99 mizoribine- and 98 placebo-treated patients. The relapse rate was lower in the mizoribine group than in the placebo group (0.0055 vs. 0.0067; ratio 0.81, 95% CI, 0.61 to 1.05, P = 0.12). The hazard ratio of the cumulative remission rate between the two groups was 0.79 (95% CI, 0. 57 to 1.08). In the subgroups consisting of patients 10 years old or younger, the relapse rate ratio between the mizoribine subgroup (54 patients) and the placebo subgroup (57 patients) was 0.66 (95% CI, 0. 44 to 0.94, P = 0.017). The hazard ratio of the cumulative remission rate between the two subgroups was 0.56 (95% CI, 0.37 to 0.85, P = 0. 007). Hyperuricemia was the most common adverse event with mizoribine (16%), but was transient.

CONCLUSIONS

Compared with the placebo, mizoribine significantly decreased the relapse rate and prolonged the remission period in the subgroup consisting of patients 10 years old or younger. This drug may be useful in young children with FRNS who generally relapse more frequently than older children.

Haemophilus parainfluenzae antigen and antibody in children with IgA nephropathy and Henoch-Schönlein nephritis

Although the pathogenesis of immunoglobulin A (IgA) nephropathy and Henoch-Schönlein nephritis (HSN) remains uncertain, there is substantial evidence that they are immune complex-mediated diseases. Recently, Haemophilus parainfluenzae antigens were shown in the glomerular mesangium of adult patients with IgA nephropathy, and greater levels of IgA antibody against H parainfluenzae were also shown in the sera of adult patients with IgA nephropathy. The present study was performed to detect H parainfluenzae antigens and antibody against H parainfluenzae in children with IgA nephropathy and HSN. H parainfluenzae antigens in the mesangium were examined by indirect immunofluorescence, and antibody against H parainfluenzae was examined by enzyme-linked immunosorbent assay. Diffuse global staining of the mesangium with rabbit antisera against H parainfluenzae was shown in 10 of the 32 patients (31%) with IgA nephropathy and 12 of the 34 patients (35%) with HSN. Conversely, only 2 of the 47 patients (4%) with other renal diseases showed staining of glomeruli with rabbit antisera against H parainfluenzae (IgA nephropathy versus other renal diseases, P = 0.003; HSN versus other renal diseases, P = 0.0006). Patients with IgA nephropathy and those with HSN showed significantly greater levels of plasma IgA1 antibody against H parainfluenzae than patients with other renal diseases (IgA nephropathy versus other renal diseases, P = 0.008; HSN versus other renal diseases, P = 0.025). These findings suggest that H parainfluenzae has a role in the cause of these two conditions in a subset of patients.

Platelet-activating factor acetylhydrolase gene mutation in Japanese children with Escherichia coli O157-associated hemolytic uremic syndrome

Platelet-activating factor (PAF) may be involved in the pathogenesis of Escherichia coli O157-associated hemolytic uremic syndrome (HUS). PAF is degraded to inactive products by PAF acetylhydrolase. In this study, we investigated whether a PAF acetylhydrolase gene mutation (G-->T transversion at position 994) is involved in HUS in Japanese children. A point mutation in the PAF acetylhydrolase gene (G994T) was identified using polymerase chain reaction in 50 Japanese children with E coli O157-associated HUS and 100 healthy Japanese. We then determined the relationship between the PAF acetylhydrolase G994T gene mutation and clinical features of HUS. There was no difference in genotype and allele frequencies between patients with HUS and healthy controls. The mean duration of oligoanuria was significantly longer in patients with the GT genotype than in those with the GG genotype (P = 0.012). Although 11 of 15 patients (73%) heterozygous for the mutant allele (GT) required dialysis, only 13 of the 35 wild-type homozygotes (GG; 37%) required dialysis (P = 0. 030). Mean plasma PAF acetylhydrolase activity was significantly less in patients with the GT genotype than in those with the GG genotype (P < 0.0001). In conclusion, we have shown an association between the G994T PAF acetylhydrolase gene mutation and the severity of renal damage in E coli O157-associated HUS. Our study suggests that analysis of the PAF acetylhydrolase gene mutation in Japanese children with E coli O157-associated HUS may allow the prediction of the severity of HUS.

Genetics of immunoglobulin A nephropathy

INTRODUCTION

Immunoglobulin (Ig) A nephropathy is the most common primary glomerulonephritis in the world and about 20% to 50% of patients with it develop progressive renal failure. There is considerable evidence to show that IgA nephropathy is influenced by genetic factors. The purpose of this review is to provide useful information concerning genetics of IgA nephropathy.

METHODS AND RESULTS

Epidemiological, familial clustering, human leukocyte antigen and IgA immune system (immunoglobulin class switch gene, I alpha 1 germ-line transcript regulatory region gene) studies have led to the hypothesis of genetic susceptibility to IgA nephropathy. Moreover, research on renin angiotensin system, platelet activating factor acetylhydrolase, neuropeptide Y Y1 receptor and others genes has demonstrated that genetic factors influence the pathological severity and natural course of IgA nephropathy.

CONCLUSIONS

The evidence presented in this review strongly supports the role of genetic factors in IgA nephropathy. Detection of genetic risk factors for IgA nephropathy will allow us to study further the pathogenesis of IgA nephropathy and devise effective therapy.

Transgenic Nicotiana occidentalis Plants Expressing the 50-kDa Protein of Apple chlorotic leaf spot virus Display Increased Susceptibility to Homologous Virus, but Strong Resistance to Grapevine berry inner necrosis virus

ABSTRACT The 50-kDa protein (P50) encoded by the open reading frame 2 of Apple chlorotic leaf spot virus (ACLSV), a putative movement protein, was expressed in transgenic Nicotiana occidentalis plants. P50 in transgenic plants was mainly detected in a modified form in the cell wall fraction, similar to that in infected leaves. The P50-expressing plants (P50 plants) complemented the systemic spread of the P50-defective mutants of an infectious cDNA clone of ACLSV (pCLSF), indicating that P50 in transgenic plants was functional. Severity of symptoms was greatly enhanced and accumulation of virus in upper leaves was increased in P50 plants inoculated with pCLSF or ACLSV compared with that in nontransgenic control plants (NT plants). Conversely, transgenic plants expressing the coat protein of ACLSV (CP plants) showed a significant delay in symptom development and a reduction of virus accumulation. However, most P50 plants inoculated with Grapevine berry inner necrosis virus (GINV), another species of the genus Trichovirus, neither developed obvious symptoms nor supported virus accumulation in inoculated or upper leaves. In contrast, systemic symptoms developed and virus accumulated equally in NT and CP plants inoculated with GINV. After inoculation with Apple stem grooving virus or Apple stem pitting virus, there was no difference in symptom development and virus accumulation among P50, CP, and NT plants. Our results indicate that transgenic plants expressing a functional P50 were more susceptible to homologous virus and, on the contrary, showed strong resistance to the heterologous virus GINV.

Nucleotide sequence and genome organization of apple latent spherical virus: a new virus classified into the family Comoviridae

A virus with isometric virus particles (ca. 25 nm) was isolated from an apple tree and named Apple latent spherical virus (ALSV). Virus particles purified from infected Chenopodium quinoa formed two bands with densities of 1.41 and 1.43 g/cm(3) in CsCl equilibrium density-gradient centrifugation, indicating that the virus is composed of two components. The virus had two ssRNA species (RNA1 and RNA2) and three capsid proteins (Vp25, Vp24 and Vp20). The complete nucleotide sequences of RNA1 and RNA2 were determined to be 6815 nt and 3384 nt excluding the 3' poly(A) tail, respectively. RNA1 contains two partially overlapping ORFs encoding polypeptides of molecular mass 23 kDa ('23K'; ORF1) and 235 kDa ('235K'; ORF2); RNA2 has a single ORF encoding a polypeptide of 108 kDa ('108K'). The 235K protein has, in order, consensus motifs of the protease cofactor, the NTP-binding helicase, the cysteine protease and the RNA polymerase, in good agreement with the gene arrangement of viruses in the COMOVIRIDAE: The 108K protein contains an LPL movement protein (MP) motif near the N terminus. Direct sequencing of the N-terminal amino acids of the three capsid proteins showed that Vp25, Vp20 and Vp24 are located in this order in the C-terminal region of the 108K protein. The cleavage sites of the 108K polyprotein were Q/G (MP/Vp25 and Vp25/Vp20) and E/G (Vp20/Vp24). Phylogenetic analysis of the ALSV RNA polymerase domain showed that ALSV falls into a cluster different from the nepo-, como- and fabavirus lineages.

FK506 augments glucocorticoid-mediated cyclooxygenase-2 down-regulation in human rheumatoid synovial fibroblasts

Prostaglandins (PG) formed by cyclooxygenase (COX) enzymes are important mediators of inflammation in rheumatoid arthritis. The contribution of the inducible COX-2 to inflammation in the rheumatoid synovium is well documented. We examined the regulation of COX-2 mRNA and protein expression in response to both glucocorticoids (GC) and FK506 using rheumatoid synovial fibroblasts. Combined treatment of FK506 and a low concentration of dexamethasone (DEX) (10(-9) M) down-regulated synovial COX-2 mRNA and protein expression. In contrast, neither FK506 nor DEX (10(-9) M) alone influenced COX-2 expression. Immunocytochemical studies showed that pretreatment with FK506 enhanced the nuclear translocation of the glucocorticoid receptor (GR) in synovial fibroblasts in the presence of low concentrations of DEX (10(-9) M). Transient transfection experiments showed that treatment of cells with FK506 enhanced the expression of glucocorticoid-responsive gene reporter in the presence of DEX (10(-9) M). NF-kappaB is known to mediate the transcriptional activation of the COX-2 gene. Electrophoretic mobility shift assay demonstrated that DNA-binding activity of NF-KB was suppressed more profoundly by FK506 plus DEX (10(-9) M) treatment with those of DEX (10(-9)M) alone in IL-1beta-stimulated synovial cells. Our results indicated that FK506-induced potentiation of GR-mediated repression of synovial COX-2 gene transcription is the result of increased translocation of GR to the nucleus and subsequent repression of NF-kappaB transactivation. Our results also suggest that FK506 may exert anti-inflammatory effects in the rheumatoid synovium by potentiating GR-mediated signal transduction.

Gradients in cytoplasmic calcium concentration ([Ca2+]i) in migrating human umbilical vein endothelial cells (HUVECs) stimulated by shear-stress

Using a parallel-plate flow-chamber and confocal laser scanning microscopy (CLSM), we studied the distribution and temporal changes in intracellular Ca2+ concentration ([Ca2+]i) in migrating HUVECs stimulated by shear-stress. In the presence or absence of ATP, shear-stress (10 dyne/cm2) caused morphological change and migration of individual HUVECs in the random direction. After 120 minute exposure to shear-stress, 70% of the cells migrated in the direction of flow, whereas, as many as 30% of the cells migrated to the upstream against flow. A nonspecific plasma membrane Ca2+ channel blocker, Ni2+, abolished such responses markedly, suggesting that Ca2+ influx may be essential for shear-stress dependent morphological change and migration of HUVECs. Analysis of [Ca2+]i distribution revealed the appearance of localized [Ca2+]i elevation inside lamellipodium formed in the direction of cell migration. The localized rise in [Ca2+]i might be closely related with morphological change to regulate the direction of cell migration induced by shear-stress.