Induction of apoptosis by dexamethasone in the B cell lineage

Live Triple Gene-Deleted Pseudorabies Virus-Vectored Subunit PCV2b and CSFV Vaccine Undergoes an Abortive Replication Cycle in the TG Neurons following Latency Reactivation

Like other alpha herpesviruses, pseudorabies virus (PRV) establishes lifelong latency in trigeminal ganglionic (TG) neurons. Upon stress, the latent viruses in the TG neurons reactivate and are transported anterograde from the neuron cell bodies to the nerve endings in the nasal mucosa, where they replicate and are discharged in the nasal and oral secretions. Consequently, the virus is transmitted to other naïve animals. This cycle of latency and reactivation continues until the animal dies or is slaughtered. We have constructed a PRV triple mutant virus (PRVtmv) and used it as a live subunit vaccine vector against porcine circovirus 2b (PCV2b) and classical swine fever virus (CSFV) (PRVtmv+). We compared the latency reactivation properties of PRVtmv+ with its parent wild-type (wt) Becker strain following intranasal infection. The results showed that PRV wt and PRVtmv+ established latency in the TG neurons. Based on nasal virus shedding, immediate early (infected cell protein 0; ICP0) and late genes, MCP (major capsid protein) and gC (glycoprotein C) transcriptions, and viral DNA copy numbers in the TGs of latently infected and dexamethasone (Dex)-treated pigs, both PRV wt and PRVtmv+ reactivated from latency. We noticed that PRV wt virus replicated productively in the terminally differentiated, postmitotic TG neurons, but PRVtmv+ failed to replicate and, therefore, there was no virus production in the TG. In addition, we found that only the PRV wt virus was shed in the nasal secretions following the Dex-induced reactivation. Our results demonstrated that the PRVtmv+ is safe as a live viral subunit vaccine vector without the possibility of productive replication in the TG upon reactivation from latency and without subsequent nasal virus shedding. This property of PRVtmv+ precludes the possibility of vaccine virus circulation in pigs and the risk of reversion to virulence.

Immunotherapy in autoimmune encephalitis

PURPOSE OF REVIEW

Autoimmune encephalitis (AE) refers to immune-mediated neurological syndromes often characterised by the detection of pathogenic autoantibodies in serum and/or cerebrospinal fluid which target extracellular epitopes of neuroglial antigens. There is increasing evidence these autoantibodies directly modulate function of their antigens in vivo. Early treatment with immunotherapy improves outcomes. Yet, these patients commonly exhibit chronic disability. Importantly, optimal therapeutic strategies at onset and during escalation remain poorly understood. In this review of a rapidly emerging field, we evaluate recent studies on larger cohorts, registries, and meta-analyses to highlight existing evidence for contemporary therapeutic approaches in AE.

RECENT FINDINGS

We highlight acute and long-term treatments used in specific AE syndromes, exemplify how understanding disease pathogenesis can inform precision therapy and outline challenges of defining disability outcomes in AE.

SUMMARY

Early first-line immunotherapies, including corticosteroids and plasma exchange, improve outcomes, with emerging evidence showing second-line immunotherapies (especially rituximab) reduce relapse rates. Optimal timing of immunotherapy escalation remains unclear. Routine reporting of outcome measures which incorporate cognitive impairment, fatigue, pain, and mental health will permit more accurate quantification of residual disability and comprehensive comparisons between international multicentre cohorts, and enable future meta-analyses with the aim of developing evidence-based therapeutic guidelines.

Light-Triggered Drug Release from Red Blood Cells Suppresses Arthritic Inflammation

Arthritis is a leading cause of disability in adults, which can be intensely incapacitating. The location and intensity of the pain is both subjective and challenging to manage. Consequently, patient-directed delivery of anti-inflammatories is an essential component of future therapeutic strategies for the management of this disorder. We describe the design and application of a light responsive red blood cell (RBC) conveyed dexamethasone (Dex) construct that enables targeted drug delivery upon illumination of the inflamed site. The red wavelength (650 nm) responsive nature of the phototherapeutic was validated using tissue phantoms mimicking the light absorbing properties of various skin types. Furthermore, photoreleased Dex has the same impact on cellular responses as conventional Dex. Murine RBCs containing the photoactivatable therapeutic display comparable circulation properties as fluorescently labelled RBCs. In addition, a single dose of light-targeted Dex delivery is 5-fold more effective in suppressing inflammation than the parent drug, delivered serially over multiple days. These results are consistent with the notion that the circulatory system be used as an on-command drug depot, providing the means to therapeutically target diseased sites both efficiently and effectively.

Splenic Micronodular T-Cell/Histiocyte-Rich Large B-Cell Lymphoma: The Corticosteroid Pretreatment Hypothesis

Splenic micronodular T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is derived from diffuse large B-cell lymphoma N.O.S., perhaps with some affinity with nodal THRLBCL. Of note, in contrast with the latter, the only lymph nodes involved in association with the splenic micronodular pattern of the disease are the splenic hilar lymph nodes. The possibility that corticosteroids, when prescribed prior to splenectomy, cause histopathological and functional modulations, apoptosis, necrosis, tissue shrinkage, which may obscure the diagnostic morphological features of this variant lymphoma and cause an underdiagnosis of this condition. The indications for glucocorticoid therapy are either related to the lymphoma itself, or else to other comorbidities, like asthma and autoimmune disorders. We propose that patients with the splenic subset of the disease are likely to have been prescribed corticosteroids prior to histopathologic examination of the involved spleen, causing disparate morphologies. However, a reviewer might accidentally dismiss the corticosteroid pretreatment which is thus overlooked. Apoptosis, induced by corticosteroids, is hypothesized as the major mechanism initiating the histopathological and functional changes in the splenic micronodular variant of the lymphoma.

Proliferative glomerulonephritis with monoclonal immunoglobulin G deposits in a young woman: A case report

BACKGROUND

Proliferative glomerulonephritis with monoclonal immunoglobulin G (IgG) deposits (PGNMID) is a newly recognized rare disease. The renal pathology is characterized by prominent manifestations of membranous hyperplasia, which are easy to misdiagnose. The clinical symptoms are severe. Massive proteinuria and hypoproteinemia are conspicuous, and most patients are accompanied by renal insufficiency and microscopic hematuria.

CASE SUMMARY

A 27-year-old woman was admitted to a hospital for macroscopic hematuria and proteinuria 4 years prior, and renal biopsy in the hospital suggested moderate-to-severe mesangial proliferating glomerulonephritis (MsPGN). She had taken a glucocorticoid, cyclophosphamide, mycophenolate mofetil, and other treatments and achieved brief partial remission. Recently, the patient visited our hospital due to massive proteinuria. Repeated renal biopsy and re-evaluation of the first biopsy obtained 4 years previously revealed monoclonal immunoglobulin deposition in the glomeruli. A bone marrow examination was performed to exclude hematologic malignancy, and a diagnosis of PGNMID was established. The patient showed remission after four cycles of a bortezomib + cyclophosphamide + dexamethasone scheme.

CONCLUSION

PGNMID is usually misdiagnosed as MsPGN or membranoproliferative glomerulonephritis. Although it often occurs in middle-aged and elderly individuals, it cannot be readily excluded in young people, even when serum immunofixation electrophoresis is negative. IgG subtype and light chain staining are necessary when this disease is highly suspected. An accurate diagnosis at the earliest stage may avoid the overuse of glucocorticoids and immunosuppressants.

Effects of steroid therapy in patients with severe fever with Thrombocytopenia syndrome: A multicenter clinical cohort study

BACKGROUND

Severe fever with thrombocytopenia syndrome (SFTS) is an acute, febrile, and potentially fatal tick-borne disease caused by the SFTS Phlebovirus. Here, we evaluated the effects of steroid therapy in Korean patients with SFTS.

METHODS

A retrospective study was performed in a multicenter SFTS clinical cohort from 13 Korean university hospitals between 2013 and 2017. We performed survival analysis using propensity score matching of 142 patients with SFTS diagnosed by genetic or antibody tests.

RESULTS

Overall fatality rate was 23.2%, with 39.7% among 58 patients who underwent steroid therapy. Complications were observed in 37/58 (63.8%) and 25/83 (30.1%) patients in the steroid and non-steroid groups, respectively (P < .001). Survival analysis after propensity score matching showed a significant difference in mean 30-day survival time between the non-steroid and steroid groups in patients with a mild condition [Acute Physiology and Chronic Health Evaluation II (APACHE II) score <14; 29.2 (95% CI 27.70-30.73] vs. 24.9 (95% CI 21.21-28.53], P = .022]. Survival times for the early steroid (≤5 days from the start of therapy after symptom onset), late steroid (>5 days), and non-steroid groups, were 18.4, 22.4, and 27.3 days, respectively (P = .005).

CONCLUSIONS

After steroid therapy, an increase in complications was observed among patients with SFTS. Steroid therapy should be used with caution, considering the possible negative effects of steroid therapy within 5 days of symptom onset or in patients with mild disease (APACHE II score <14).

Reactivation of cyprinid herpesvirus 2 (CyHV-2) in asymptomatic surviving goldfish Carassius auratus (L.) under immunosuppression

Cyprinid herpesvirus 2 (CyHV-2) is a highly contagious pathogen of goldfish (Carassius auratus) and Prussian carp (Carassius auratus gibelio) causing herpesviral hematopoietic necrosis. Our previous study revealed that CyHV-2 can persistently infect the kidney and spleen of goldfish that recovered from a primary infection. In this study, we tried to identify the cells persistently infected with the virus in surviving fish and investigated virus reactivation in the survivors injected with immunosuppressants, namely dexamethasone (Dex) and cyclosporine A (CsA). Virus DNA was detected from the monocytes that were isolated from the trunk kidney of the asymptomatic survivors, suggesting that monocytes/macrophages are major cells that may be persistently infected with CyHV-2. A significant increase of virus DNA levels was detected in the group injected with Dex at 10 and 21 days post-injection (dpi). In the fish group injected with CsA, the virus DNA level was the same as that in the control group at 10 dpi but increased in some organs at 21 dpi. Compared with Dex-injected fish at 10 dpi, the group injected with both Dex and CsA showed a greater increase in virus DNA levels. The gene expression of phagocytosis-associated genes, major histocompatibility complex (MHC) class II and p47^phox, and anti-virus antibody levels increased in the CsA group due to virus reactivation in the infected cells but not in the Dex and Dex & CsA groups, indicating that Dex effectively suppressed monocyte/macrophage function and antibody production. In addition, recombinant interferon γ (IFNγ) supplementation in the kidney leukocyte culture that was isolated from survivors showed a reduction of virus DNA. CsA may inhibit T-helper 1 (Th1) cells and consequently IFNγ production, causing a synergetic effect with Dex on virus reactivation. The results suggest that the activity of monocytes/macrophages stimulated by IFNγ can relate to virus latency and reactivation in asymptomatic virus carriers.

Glucocorticoid susceptibility and in vivo ABCB1 activity differ in murine B cell subsets

Glucocorticoids are produced and released by the adrenal gland and become elevated in response to stress. Although glucocorticoids are well known for their immunosuppressive effects, less is known about their effects on B cells. ABCB1 is an efflux pump expressed in both cancer and normal cells, modulating the gradient of various metabolites, including hydrocortisone. Our goal was to evaluate the effect of this glucocorticoid on murine B cell differentiation and whether sensitivity to hydrocortisone could be related to ABCB1 activity in vivo. C57BL/6 mice received one or three consecutive i.p. injections of hydrocortisone (70, 140 and 200 mg/kg/day). ABCB1 activity was evaluated via the rhodamine-123 transport and inhibited by cyclosporin A in hydrocortisone-treated and control mice. Cells from bone marrow, spleen and blood were counted, incubated with antibodies and analyzed by flow cytometry. A single hydrocortisone injection did not alter the number of bone marrow subsets. Conversely, three daily injections were able to reduce the cell number of most bone marrow subsets, excepting c-kit-sca-1+ and mature B cells. This treatment reduced marginal zone, follicular and transitional B cells, though splenic subsets were more resistant than bone marrow B cells. Recirculating follicular B cells in the blood were resistant to hydrocortisone. With the exception of follicular B cells, all subpopulations exhibited ABCB1 activity. However, hydrocortisone treatment did not affect ABCB1 activity in most subsets analyzed. Results suggest that hydrocortisone is able to regulate B cell lymphopoiesis although ABCB1 activity is not related to the susceptibility to that glucocorticoid in B cell subsets.

Multiple sclerosis pathogenesis: missing pieces of an old puzzle

Traditionally, multiple sclerosis (MS) was considered to be a CD4 T cell-mediated CNS autoimmunity, compatible with experimental autoimmune encephalitis model, which can be characterized by focal lesions in the white matter. However, studies of recent decades revealed several missing pieces of MS puzzle and showed that MS pathogenesis is more complex than the traditional view and may include the following: a primary degenerative process (e.g. oligodendroglial pathology), generalized abnormality of normal-appearing brain tissue, pronounced gray matter pathology, involvement of innate immunity, and CD8 T cells and B cells. Here, we review these findings and discuss their implications in MS pathogenesis.

Treating the idiopathic nephrotic syndrome: are steroids the answer?

The use of steroids in idiopathic nephrotic syndrome is the major discovery of the twentieth century in the field of pediatric nephrology. At onset of the twenty-first century, steroids remain the first line of treatment at first flare. All the protocols to treat the first flare are similar by a common sequence including a first phase of daily prednisolone/prednisone at a dose of 60 mg/m²/day for at least 4 weeks followed by an alternate-day regimen for several weeks. It appears that a cumulated dose of 2240 mg/m² given in 8 weeks at the first flare without tapering sequence is not inferior to increased dose and duration in terms of prevalence of frequent relapsers and the subsequent cumulated dose of steroids at 24 months of follow-up. A higher cumulated dose might only be interesting in patients aged below 4 years although a formal demonstration is still missing. Several retrospective studies are concordant to suggest that intravenous methylprednisolone pulses are useful to reach a full urinary remission in case of oral resistance to 4 weeks of oral prednisone/prednisolone. A majority of patients have multiple relapses after the treatment of the first flare and half meet the definition of steroid dependency. In those patients, long-lasting alternate-day prednisone/prednisolone therapy does not lead to long-lasting remission, opening the question of the best strategy of immunosuppression.

Pharmacology of Corticosteroids for Diabetic Macular Edema

Purpose

Corticosteroids remain the mainstay of treatment for inflammatory diseases almost 80 years after their first clinical use. Topical ophthalmic formulations of corticosteroids have been available to treat disease of the anterior segment of the eye, but the approval of corticosteroids to treat vitreoretinal diseases, including vein occlusion, diabetic macular edema, and uveitis, has occurred only recently. Although most diseases respond to corticosteroid therapy, some patients are resistant to this therapy and side effects, including cataract and elevated intraocular pressure, can limit their use. The purpose of this review is to detail the basic science of corticosteroids focusing on differences in potency, drug delivery, pharmacokinetics, and gene activation, and how these differences affect safety and efficacy in the treatment of diabetic macular edema.

Methods

A review was conducted of basic science and pharmacology of the corticosteroids used to treat diabetic macular edema.

Results

Clinically available corticosteroids not only have differing potency and pharmacokinetics, but also activate different genes in different target tissues. These differences are associated with distinct efficacy, pharmacokinetic, and safety profiles. It is important to understand these differences in selecting corticosteroids to treat diabetic macular edema.

Conclusions

Recent advances in our understanding of the basic science of corticosteroids can explain clinical differences in these agents regarding efficacy and safety. Importantly, this understanding should allow the future discovery of additional novel corticosteroids to treat diabetic macular edema.

Idiopathic nephrotic syndrome: the EBV hypothesis

Steroid sensitive nephrotic syndrome is marked by a massive proteinuria and loss of podocytes foot processes. The mechanism of the disease remains debated but recent publications suggest a primary role of Epstein-Barr Virus (EBV). EBV replication in the peripheral blood is found in 50% of patients during the first flare of the disease. The genetic locus of steroid sensitive nephrotic syndrome was also identified as influencing antibodies directed against EBNA1. EBV is able to establish, latent benign infection in memory B cells that display phenotypes similar to antigen-selected memory B cells. Consistently, memory B cells reconstitution after rituximab infusion is a predictor of the relapse of proteinuria. We suggest that a specific anti-EBNA1 antibody internalized in the podocytes via the neonatal Fc receptor might cross-react with a major protein present in the same cell trafficking compartment. The diversion of this major podocyte protein in the urinary space and the subsequent depletion is supposed to result in podocyte damages with loss of foot processes and massive proteinuria. Immunosuppression of B cells and subsequent clearance of anti-EBNA1 antibodies would lead to a restoration of the normal level of the protein allowing recovery of proteinuria and of normal podocyte morphology.

Dexamethasone Suppresses Oxysterol-Induced Differentiation of Monocytic Cells

Oxysterol like 27-hydroxycholesterol (27OHChol) has been reported to induce differentiation of monocytic cells into a mature dendritic cell phenotype. We examined whether dexamethasone (Dx) affects 27OHChol-induced differentiation using THP-1 cells. Treatment of monocytic cells with Dx resulted in almost complete inhibition of transcription and surface expression of CD80, CD83, and CD88 induced by 27OHChol. Elevated surface levels of MHC class I and II molecules induced by 27OHChol were reduced to basal levels by treatment with Dx. A decreased endocytosis ability caused by 27OHChol was recovered by Dx. We also examined effects of Dx on expression of CD molecules involved in atherosclerosis. Increased levels of surface protein and transcription of CD105, CD137, and CD166 by treatment with 27OHChol were significantly inhibited by cotreatment with Dx. These results indicate that Dx inhibits 27OHChol-induced differentiation of monocytic cells into a mature dendritic cell phenotype and expression of CD molecules whose levels are associated with atherosclerosis. In addition, we examined phosphorylation of AKT induced by 27OHChol and effect of Dx, where cotreatment with Dx inhibited the phosphorylation of AKT. The current study reports that Dx regulates oxysterol-mediated dendritic cell differentiation of monocytic cells.

Outcome of corticosteroid administration in autoimmune pulmonary alveolar proteinosis: a retrospective cohort study

Background

Although no report has demonstrated the efficacy of corticosteroid therapy for autoimmune pulmonary alveolar proteinosis (aPAP), we sometimes encounter patients who have received this therapy for various reasons. However, as corticosteroids can suppress alveolar macrophage function, corticosteroid therapy might worsen disease severity and increase the risk of infections.

Methods

For this retrospective cohort study, we sent a screening form to 165 institutions asking for information on aPAP patients treated with corticosteroids. Of the resulting 45 patients screened, 31 were enrolled in this study. We collected demographic data and information about corticosteroid treatment period, dose, disease severity score (DSS) over the treatment period, and complications.

Results

DSS deteriorated during corticosteroid therapy in 23 cases (74.1 %) and the estimated overall cumulative worsening rate was 80.8 % for the total observation period. The worsening rate was significantly higher in patients treated with high-dose prednisolone (>18.9 mg/day, n = 16) than treated with low-dose prednisolone (≤18.9 mg/day, n = 15) divided by median daily dose (p < 0.02). Of patients with worsening, one died of disseminated aspergillosis and another of respiratory failure. Infections newly emerged in 6 cases during corticosteroid therapy (p < 0.05). Median serum granulocyte/macrophage colony-stimulating factor (GM-CSF) autoantibody levels were similar to previously reported data in a large cohort study.

Conclusion

The results demonstrate that corticosteroid therapy may worsen DSS of aPAP, increasing the risk for infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0085-0) contains supplementary material, which is available to authorized users.

Dexamethasone Intravitreal Implant as Adjunctive Therapy to Ranibizumab in Neovascular Age-Related Macular Degeneration: A Multicenter Randomized Controlled Trial

Purpose: To evaluate the efficacy and safety of dexamethasone intravitreal implant 0.7 mg (DEX) as adjunctive therapy to ranibizumab in neovascular age-related macular degeneration (nvAMD). Procedures: This was a 6-month, single-masked, multicenter study. Patients were randomized to DEX implant (n = 123) or sham procedure (n = 120) and received 2 protocol-mandated intravitreal ranibizumab injections. The main outcome measure was injection-free interval to first as-needed ranibizumab injection. Results: DEX increased the injection-free interval versus sham (50th percentile, 34 vs. 29 days; 75th percentile, 85 vs. 56 days; p = 0.016). 8.3% of DEX versus 2.5% of sham-treated patients did not require rescue ranibizumab (p = 0.048). Visual acuity and retinal thickness outcomes were similar in DEX and sham-treated patients. Only reports of conjunctival hemorrhage (18.2 vs. 8.5%) and intraocular pressure elevation (13.2 vs. 4.2%) were significantly different in the DEX versus the sham treatment groups. Conclusion: DEX reduced the need for adjunctive ranibizumab treatment and showed acceptable tolerability in nvAMD patients.

The liver protective effect of methylprednisolone on a new experimental acute-on-chronic liver failure model in rats

BACKGROUND

Acute-on-chronic liver failure is a severe, life-threatening entity and the comprehension of this disease is incomplete. Currently, a reasonable surgical model of acute-on-chronic liver failure is still lacking. The aim of this study was to establish a new model of acute-on-chronic liver failure in rats and to investigate the protective effects of methylprednisolone on this model.

METHODS

An obstructive jaundice model in rats was established. Two weeks later, the animals were subjected to a choledochoduodenostomy and a reduced-size hepatic ischaemia/reperfusion injury. Animals were randomly divided into a control group, a methylprednisolone injected via the tail vein group and a methylprednisolone injected via the portal vein group. The survival rates and serum levels of alanine transaminase, aspartate aminotransferase, total bilirubin, tumour necrosis factor alpha, and interferon gamma of the rats were measured and the pathological changes in liver tissues were observed.

RESULTS

The survival rate was significantly improved in the methylprednisolone treatment groups. Serum levels of the biochemical indexes were the lowest in the portal vein injection group. Liver tissues under microscopy presented severe pathological injury in the control group.

CONCLUSION

This model could be useful for further research into acute-on-chronic liver failure and methylprednisolone may be a potential therapeutic agent for this disease.

Early dexamethasone treatment exacerbates enterovirus 71 infection in mice

Enterovirus 71 (EV71) infection can induce encephalitis. Overt immune responses is suspected to cause severe symptoms, so anti-inflammatory agents, corticosteroids have been recommended for treatment. However, one clinical study reported that treatment with glucocorticoids, dexamethasone (Dex) exacerbates disease severity. Here we investigated Dex treatment on EV71 infection using the murine model and found that both long-term (14-day) and short-term (4-day) Dex treatment starting from 1 or 3 days postinfection increased the mortality and disease severity of infected mice. Dex treatment starting from 4 or 8 days postinfection did not affect mouse mortality and disease severity. Early Dex treatment starting from 1 day postinfection caused atrophy and enhanced apoptosis in lymphoid organs to decrease the numbers of lymphocytes (CD4(+) T cells, CD8(+) T cells, and CD19(+) B cells) and to increase viral loads in infected tissues of mice. Our results demonstrate that Dex treatment has no beneficial effect on EV71 infection.

Cutting edge: Dexamethasone potentiates the responses of both regulatory T cells and B-1 cells to antigen immunization in the ApoE(-/-) mouse model of atherosclerosis

The immunosuppressant dexamethasone was shown to preferentially deplete CD4+ effector T cells while sparing regulatory T cells (Tregs) in vivo. In the current study, we show that it also preferentially depletes B-2 cells while sparing B-1 cells. In the ApoE(-/-) mouse model of atherosclerosis, in which both Tregs and B-1 cells are thought to play an atheroprotective role, we show that HSP60-targeted immunization in the presence of dexamethasone raises Ag-reactive Tregs and B-1 cells concomitantly and reduces the severity of atherosclerosis. These results indicate that dexamethasone is an adjuvant that potentiates both the Treg and B-1 responses to immunogens. This study shows that B-1 cells with a specificity for a disease-relevant Ag can be raised in vivo by immunization.

Effect of dexamethasone on development of in vitro-produced bovine embryos

Studies in somatic cells have shown that glucocorticoids such as dexamethasone (DEX) may trigger or prevent apoptosis depending on the cell type in culture. Because the dysregulation of apoptosis may lower in vitro embryo production efficiency, we sought to investigate the effects of supplementing IVC medium with DEX (0.1 μg/mL) on embryo morphology, development kinetics, and apoptosis rates of in vitro-produced bovine preimplantation embryos. Embryo morphology was graded on Day 7, and development rates were assessed on Days 4 and 7 of IVC. Apoptosis was evaluated via annexin/propidium iodide staining under fluorescence microscopy where a cell labeled with annexin, propidium iodide, or both would be considered apoptotic. An embryo was counted in the apoptosis rates, if it displayed at least one such labeled cell. Although DEX supplementation did not reduce apoptosis rates, it had a positive impact on developmental kinetics and cell number both on Days 4 and 7 of embryo culture. Presumably, such effect resulted from increased cell proliferation rather than a direct inhibition of apoptosis. Further studies may evaluate the mechanisms by which glucocorticoids may affect embryo development, as DEX supplementation could become a tool to improve in vitro embryo yield in mammalian species.

Leukocytosis and enhanced susceptibility to endotoxemia but not atherosclerosis in adrenalectomized APOE knockout mice

Hyperlipidemic apolipoprotein E (APOE) knockout mice show an enhanced level of adrenal-derived anti-inflammatory glucocorticoids. Here we determined in APOE knockout mice the impact of total removal of adrenal function through adrenalectomy (ADX) on two inflammation-associated pathologies, endotoxemia and atherosclerosis. ADX mice exhibited 91% decreased corticosterone levels (P<0.001), leukocytosis (WBC count: 10.0 ± 0.4 x 10E9/L vs 6.5 ± 0.5 x 10E9/L; P<0.001) and an increased spleen weight (P<0.01). FACS analysis on blood leukocytes revealed increased B-lymphocyte numbers (55 ± 2% vs 46 ± 1%; P<0.01). T-cell populations in blood appeared to be more immature (CD62L+: 26 ± 2% vs 19 ± 1% for CD4+ T-cells, P<0.001 and 58 ± 7% vs 47 ± 4% for CD8+ T-cells, P<0.05), which coincided with immature CD4/CD8 double positive thymocyte enrichment. Exposure to lipopolysaccharide failed to increase corticosterone levels in ADX mice and was associated with a 3-fold higher (P<0.05) TNF-alpha response. In contrast, the development of initial fatty streak lesions and progression to advanced collagen-containing atherosclerotic lesions was unaffected. Plasma cholesterol levels were decreased by 35% (P<0.001) in ADX mice. This could be attributed to a decrease in pro-atherogenic very-low-density lipoproteins (VLDL) as a result of a diminished hepatic VLDL secretion rate (-24%; P<0.05). In conclusion, our studies show that adrenalectomy induces leukocytosis and enhances the susceptibility for endotoxemia in APOE knockout mice. The adrenalectomy-associated rise in white blood cells, however, does not alter atherosclerotic lesion development probably due to the parallel decrease in plasma levels of pro-atherogenic lipoproteins.

B cells and antibodies in multiple sclerosis pathogenesis and therapy

B cells and antibodies account for the most prominent immunodiagnostic feature in patients with multiple sclerosis (MS), namely oligoclonal bands. Furthermore, evidence is accumulating that B cells and antibodies contribute to MS pathogenesis in at least a subset of patients. The CNS provides a B-cell-fostering environment that includes B-cell trophic factors such as BAFF (B-cell-activating factor of the TNF family), APRIL (a proliferation-inducing ligand), and the plasma-cell survival factor CXCL12. Owing to this environment, the CNS of patients with MS is not only the target of the immunopathological process, but also becomes the site of local antibody production. B cells can increase or dampen CNS inflammation, but their proinflammatory effects seem to be more prominent in most patients, as B-cell depletion is a promising therapeutic strategy. Other therapies not primarily designed to target B cells have numerous effects on the B-cell compartment. This Review summarizes key features of B-cell biology, the role of B cells and antibodies in CNS inflammation, and current attempts to identify the targets of pathogenic antibodies in MS. We also review the effects of approved and investigational interventions-including CD20-depleting antibodies, BAFF/APRIL-depleting agents, alemtuzumab, natalizumab, FTY720, IFN-β, glatiramer acetate, steroids and plasma exchange-on B-cell immunology.

Alterations in the primary diagnosis of lymphomas pretreated with corticosteroid agents

Little is known of the role of preliminary corticosteroids in clinical and morphological modifications and in difficulties in reaching a diagnosis in patients with lymphoma. We identified 31 patients who were given steroids before biopsy for primary diagnosis. We looked for the reason for steroid pretreatment, its dose, and duration. We evaluated the difficulty in reaching the primary diagnosis and whether a secondary diagnosis was made. The patients' slides were reviewed to identify secondary histological changes. Our findings suggest a variable effect of prior glucocorticoids on the clinical and histopathological alterations developing in malignant lymphomas, as well as on the complexity of the process of reaching a diagnosis.

Splenic micronodular T-cell/histiocyte-rich large B-cell lymphoma: effect of prior corticosteroid therapy

We report on three patients who were treated with corticosteroids only prior to the diagnosis of splenic lymphoma. Corticosteroids were administered for different conditions, at different doses, and for various periods of time. The primary diagnosis was splenic micronodular T-cell/histiocyte-rich large B-cell lymphoma in the three cases, and it was reached with variable difficulty. We suggest that the corticosteroid treatment was one of the causes for the complications in reaching a diagnosis. The morphologic appearance of the microscopic splenic nodules was the most variable feature and may possibly reflect the dose and duration of the corticosteroid therapy. However, the histopathologic changes are probably not related with Epstein-Barr virus-induced immunosuppression.

Heat shock protein 60, via MyD88 innate signaling, protects B cells from apoptosis, spontaneous and induced

We recently reported that heat shock protein 60 (HSP60) via TLR4 signaling activates B cells and induces them to proliferate and secrete IL-10. We now report that HSP60 inhibits mouse B cell apoptosis, spontaneous or induced by dexamethasone or anti-IgM activation. Unlike HSP60 enhancement of B cell proliferation and IL-10 secretion, TLR4 signaling was not required for the inhibition of apoptosis by HSP60; nevertheless, MyD88 was essential. Inhibition of apoptosis by HSP60 was associated with up-regulation of the antiapoptotic molecules Bcl-2, Bcl-x(L), and survivin, maintenance of the mitochondrial transmembrane potential, and inhibition of caspase-3 activation. Moreover, B cells incubated with HSP60 manifested prolonged survival following transfer into recipient mice. These results extend the varied role of HSP60 in the innate regulation of the adaptive immune response.

Stem cell mobilization in idiopathic steroid-sensitive nephrotic syndrome

Steroid-sensitive nephrotic syndrome (SSNS) is classically thought to be a T-cell disorder. The aim of this study was to examine whether or not thymus homeostasis was affected in SSNS. Mature and naive T cell recent thymic emigrants were quantified in the peripheral blood of nephrotic patients and controls. Because the generation of new T cells by the thymus ultimately depends on hematopoietic stem cells, CD34+ cells were also included in the study. Nineteen patients with SSNS during relapse, 13 with SSNS during proteinuria remission, and 18 controls were studied. Cell-surface markers (CD3, CD4, CD8, CD19, CD16, CD56, CD45RA, CD62L, CD34, and CD38) were analyzed by flow cytometric analysis. T-cell rearrangement excision circles (TRECs) were quantified in CD2+ cells by real-time polymerase chain reaction. Stroma cell-derived factor-1 (SDF-1) genotype and metalloproteinase-9 (MMP-9) plasma levels were also determined. Mature T cells (CD4+ and CD8+), circulating naive T cells (CD62L+ and CD3+ CD62L+), and recent thymic emigrants (CD45RA+) as well as TRECs, that measure thymus production, had a similar level in the three groups of patients. Conversely, CD34+ hematopoietic stem cells displayed a two-fold increase in SSNS patients during relapse either compared with controls or SSNS patients at remission. In addition, compared with controls, SSNS patients at remission displayed (1) a decrease in CD19+ cells (B cells) and (2) an increase in CD16CD56+ cells [natural killer (NK) cells]. In conclusion, thymus homeostasis is not significantly affected in nephrotic patients. Hematopoietic stem-cell mobilization at proteinuria relapse, as well as changes in B and NK cells during remission, suggest that SSNS might be due to a general disturbance of hematopoietic and immune cell trafficking.

Methylprednisolone injection via the portal vein suppresses inflammation in acute liver failure induced in rats by lipopolysaccharide and d-galactosamine

BACKGROUND

We have reported that hepatic arterial steroid injection is an effective therapy to rescue patients from fulminant or severe acute hepatic failure. We speculate that a high concentration of steroid suppresses inflammatory processes in the liver directly by restraining activated inflammatory cells, including macrophages. To analyse the detailed mechanism, steroid injection via the portal vein was performed in an experimental model of liver damage.

METHODS

Rats subjected to lipopolysaccharide and d-galactosamine injection were treated with a methylprednisolone injection via the tail vein or the portal vein. The survival rate, serum levels of inflammatory cytokines and apoptotic cell counts in the liver were analysed.

RESULTS

The survival rate was significantly improved by steroid injection, especially via the portal vein. Serum values of alanine aminotransferase, tumor necrosis factor-alpha and interferon-gamma were reduced in the treated groups, especially the group given portal venous injections. Apoptotic cell counts in the liver were significantly lower in the group injected with steroid via the portal vein.

CONCLUSION

In the model rats, high concentrations of steroid in the liver acted on inflammatory cells and suppressed inflammatory cytokines and liver cell death. The mechanism is suggested to be the same for arterial steroid injection therapy in patients with acute hepatic failure.

Treating autoimmune demyelination by augmenting lymphocyte apoptosis in the central nervous system

The elimination of autoreactive T cells from the central nervous system (CNS) by apoptosis plays an important role in switching off autoimmune attack. B-cell apoptosis in the CNS probably also has a key role in downregulating autoimmunity. Augmenting lymphocyte apoptosis in the CNS is a potential strategy for treating autoimmune CNS diseases such as multiple sclerosis. These strategies involve modulation of the physiological pro-apoptotic and anti-apoptotic pathways that control lymphocyte fate in the CNS. In the case of T cells, apoptosis can be augmented by enhancing activation-induced T-cell apoptosis through the CD95 (Fas) pathway and by inhibiting costimulation-induced anti-apoptotic pathways mediated through BCL-2 and BCL-X L.

Enhanced expression of adipocyte-type fatty acid binding protein in murine lymphocytes in response to dexamethasone treatment

Fatty acids have a great influence on the process of lymphocyte apoptosis which is considered as a modulating factor of immune response in both humans and animals. However the mechanism underlying the function of fatty acids in the process of lymphocyte apoptosis is not fully understood. In this study we show that the appearance of adipocyte-type fatty acid binding protein (A-FABP) is induced upon administration of dexamethasone (DEX) in both in vivo and cultured lymphocytes, and its distinct nuclear localization occurs in close relation to the DEX-induced apoptosis process. In immunohistochemistry of mouse spleen, A-FABP-immunoreactivity starts to occur 3 h after DEX stimulation, and it massively localizes in the nucleus 8 h after the treatment, while no A-FABP-immunoreactivity is discerned in the lymphocytes of normal as well as 24 h post-injection spleen. In the murine T-cell leukemia CTLL-2 cells, A-FABP-immunoreactivity is also induced in both of the cytoplasm and nucleus when the apoptosis is induced by IL-2 retrieval together with DEX treatment, while in the presence of IL-2 A-FABP-immunoreactivity is confined to the cytoplasm with DEX treatment. On the other hand, A-FABP-immunoreactivity is not detected by IL-2 retrieval alone. The present findings altogether suggest that A-FABP and its ligands, fatty acids, play an important role in the process of apoptosis and the immune modulation induced by DEX.

Mouse follicular and marginal zone B cells show differential expression of Dnmt3a and sensitivity to 5′-azacytidine

Mature B cells in the spleen of mouse and human comprise of two main subsets, the follicular (Fo) B cells and the marginal zone (MZ) B cells. In this study, we report that Fo and MZ B cells express different levels of DNA methyltransferase Dnmt3a. By using RT-PCR and immunohistochemistry, we found that Fo B cells expressed high level of Dnmt3a while MZ B cells expressed little. Treatment of mice by in vivo administration of 5'-azacytidine, an inhibitor of DNA methyltransferases, induced B cell loss in both the bone marrow and the spleen. We noticed that this treatment resulted in a much faster and more severe disappearance of Fo B cells than MZ B cells in the spleen. Further analysis showed that MZ progenitors increased significantly in mice treated with 5'-azacytidine. These results suggest that epigenetic mechanisms involving Dnmt3a might participate in the development of B cells including the differentiation of Fo B cells and MZ B cells in the periphery.

Potentiation of trichothecene-induced leukocyte cytotoxicity and apoptosis by TNF-alpha and Fas activation

Trichothecene mycotoxins cause immunosuppression by inducing apoptosis in lymphoid tissue. Trichothecene-induced leukocyte apoptosis can be augmented by bacterial lipopolysaccharide (LPS) but the mechanisms involved in this potentiating effect are not completely understood. The objective of this study was to test the hypothesis that the trichothecene deoxynivalenol (DON, vomitoxin) can interact with LPS directly and other mediators or agonists associated with immune/inflammatory responses to induce apoptosis in primary murine leukocyte cultures. Primary leukocyte suspensions were prepared from murine thymus (TH), spleen (SP), bone marrow (BM) and Peyer's patches (PP) and then cultured with DON in the absence or presence of LPS, prostaglandin E2 (PGE2), anti-immunoglobulin (as antigen mimic), dexamethasone, Fas ligand, or TNF-alpha. Cytotoxicity and apoptosis were evaluated by MTT assay and morphologic assays, respectively. DON was found to inhibit LPS-induced proliferation and dexamethasone-induced apoptosis in SP cultures. In contrast, potentiation of DON-induced apoptosis and cytotoxicity was observed in BM cultures treated with anti-Fas and in TH cultures treated with TNF-alpha. When potentiation of DON-induced apoptosis by TNF-alpha was assessed using pharmacological inhibitors, generation of ROS, intracellular Ca2+, p38/SAPK, and caspase-3 activation were found to play roles. Taken together, these data demonstrate that LPS and its downstream mediators can interact with trichothecenes to modulate proliferative, cytotoxic and apoptotic outcomes in leukocytes in a tissue-specific manner.

Environmental chemical-induced pro/pre-B cell apoptosis: analysis of c-Myc, p27Kip1, and p21WAF1 reveals a death pathway distinct from clonal deletion

Polycyclic aromatic hydrocarbons (PAH) are common environmental pollutants that suppress the immune system in part by inducing pro/pre-B cell apoptosis. The PAH-induced death signaling pathway resembles the signaling cascade activated during clonal deletion and modeled by B cell receptor cross-linking or by dexamethasone exposure of immature surface Ig(+) B cells in that apoptosis is mediated by NF-kappa B down-regulation. Because a PAH-induced, clonally nonrestricted deletion of B cells would have important implications for B cell repertoire development, the nature of the PAH-induced intracellular death signal was studied further. Particular emphasis was placed on the roles of growth arrest and c-Myc, p27(Kip1), and p21(WAF1) expression, because all of these elements contribute to clonal deletion. As in clonal deletion models, and as predicted by the down-regulation of NF-kappa B, PAH-induced death of pro/pre-B cells was at least partially dependent on c-Myc down-regulation. Furthermore, whereas dexamethasone induced a G(0)/G(1) cell cycle arrest, PAH had no effect on pro/pre-B cell growth, indicating that growth arrest and apoptosis occur by separable signaling pathways in this early phase of B cell development. Finally, in contrast to clonal deletion, PAH-induced pro/pre-B cell death was not dependent on p27(Kip1) or p21(WAF1) up-regulation but did coincide with p53 induction. These results distinguish the PAH-induced apoptosis pathway from that activated during clonal deletion and indicate that signaling cascades leading to growth arrest and/or apoptosis in pro/pre-B cells differ from those active at later B cell developmental stages.

Molecular basis of rifampicin-induced inhibition of anti-CD95-induced apoptosis of peripheral blood T lymphocytes: the role of CD95 ligand and FLIPs

Rifampicin modulates immune response; however, mechanisms by which it exerts these effects are incompletely understood. Recently, rifampicin has been shown to bind to and activate glucocorticoid receptors. Because of the evidence for a role of glucocorticoids in lymphocyte apoptosis, we hypothesized that rifampicin may exert its influence on the immune system by regulating apoptosis. Therefore, we examined the effect of rifampicin on signaling pathway of anti-CD95-induced apoptosis in peripheral blood lymphocytes. Rifampicin, in a concentration-dependent manner, inhibited anti-CD95-induced apoptosis in both CD4+ and CD8+ T cells, which was associated with the inhibition of activation of both caspase-3 and caspase-8. In addition, rifampicin down-regulated the expression of CD95L and Bax. The inhibitory effects of rifampicin on apoptosis and caspase activation as well as its effect on the expression of CD95L and FLIPs were reversed by RU486, an antagonist of glucocorticoid receptor. These data suggest that rifampicin inhibits anti-CD95-mediated apoptosis in lymphocytes by modulating the expression of certain proteins that regulate apoptosis, at least in part, via glucocorticoid receptors.

Cellular specificity related to monoglyceride-induced cell death

We have recently observed that monoglycerides (MGs), a family of lipids consisting of a single fatty acid moiety attached to a glycerol backbone, induce rapid dose-dependent apoptosis in murine thymocytes. In this work, we evaluated the sensitivity of various normal and malignant immune and non-immune cells to MGs. We demonstrate that the propensity to MG-induced death displayed by both T and B lymphocytes is clearly modulated according to their differentiation and activation status. For instance, the earliest T and B cell precursors are refractory to MG-mediated cell death. In the T-cell lineage, immature thymocytes are the most susceptible to MG treatment, while B cells from peripheral lymphoid organs appear more sensitive than B-cell subsets from the bone marrow. On the other hand, both activated T and B cells are more resistant to MG exposure than their non-activated counterparts. In addition, other hematopoietic lineages such as natural killer cells, macrophages, and erythroid cells are quite resistant to MG-induced death. Furthermore, using various immortalized cell lines from different tissues, we found that lymphomas and thymomas are the most sensitive among all lineages tested, while epithelial cells and fibroblasts are unaffected by MG treatment. Finally, MG-induced death was shown to be independent of Fas/Fas ligand (FasL) interactions. Altogether, our findings indicate that there is a cellular specificity related to MG-mediated cell death biased towards T and B lymphocytes. This suggests that MGs could potentially be used in the treatment of specific lymphoid disorders by bypassing the requirement for the Fas/FasL system.

Cell-specific regulation of apoptosis by glucocorticoids: implication to their anti-inflammatory action

Glucocorticoids play a major role in attenuation of the inflammatory response. These steroid hormones are able to induce apoptosis in cells of the hematopoietic system such as monocytes, macrophages, and T lymphocytes that are involved in the inflammation reaction. In contrast, it was discovered recently that in glandular cells such as the mammary gland epithelia, hepatocytes, ovarian follicular cells, and in fibroblasts glucocorticoids protect against apoptotic signals evoked by cytokines, cAMP, tumor suppressors, and death genes. The anti-apoptotic effect of glucocorticoids is exerted by modulation of several survival genes such as Bcl-2, Bcl-x(L), and NFkB, in a cell-specific manner. Moreover, upregulation or downregulation of the same gene product can occur in a cell-dependent manner following stimulation by glucocorticoids. This phenomenon is probably due to composite regulatory cross-talk among multiple nuclear coactivators or corepressors, which mediate the transcription regulation of the genes, by their interaction with the glucocorticoid receptor. These observations suggest that the anti-inflammatory action of glucocorticoids is exerted by two complementary mechanisms: on one hand, they induce death of the cells that provoke the inflammation, and on the other hand they protect the resident cells of the inflamed tissue by arresting apoptotic signals. Moreover, the complementary action of glucocorticoids provides a new insight to the therapeutic potential of these hormones.

The immunomodulatory action of dexamethasone on monoclonal antibody-producing hybridoma cells

As found in different studies, glucocorticoid hormones (GCs) as well as interleukin-6 (IL-6) are involved in the modulation of protein glycosylation. In this work we have investigated the immunomodulatory effect of dexamethasone by assessing in vitro IgG glycosylation by monoclonal antibody-producing hybridoma cells. As described in myeloma cell lines, cellular viability and proliferation rates of hybridoma 112D5 cells decrease when cultured with dexamethasone during 24 hours, in a dose-dependent way. Moreover, the corticosteroid triggered apoptosis of the hybridoma, which was observed as soon as 4 h after culturing cells in the presence of the drug. In line with these results, after 24 h, dexamethasone induced a drop in the anti-DNP level of antibodies synthesized by hybridoma 112D5. In previous works we described that asymmetric glycosylation of in vitro synthesized IgG correlated with induction of cell damage. Nevertheless, an increase in asymmetric IgG glycosylation was not observed here, but there was a decrease in the proportion of asymmetrically glycosylated IgG synthesized by the hybridoma after a 4-h culture with the drug. Finally, as results from assessing IL-6 production by ELISA, we conclude that the above described effects of dexamethasone on hybridoma 112D5 cells could not be due to the inhibition of IL-6 synthesis exerted by the corticoid but rather to a direct effect of the drug. Monoclonal antibody (MAb) producing hybridomas provide an excellent in vitro model for the study of the molecular mechanisms involved in immunoglobulin glycosylation.

The anti-inflammatory action of glucocorticoids is mediated by cell type specific regulation of apoptosis

Glucocorticoids play a major role in attenuation of the inflammatory response. These steroid hormones are able to induce apoptosis in cells of the hematopoietic system such as monocytes, macrophages and T-lymphocytes that are involved in the inflammation reaction. In contrast, it was discovered recently that in glandular cells such as the mammary gland epithelia, hepatocytes, ovarian follicular cells and in fibroblasts glucocorticoids protect against apoptotic signals evoked by cytokines, cAMP, tumor suppressors and death genes. The anti-apoptotic effect of glucocorticoids is exerted by modulation of several survival genes such as Bcl-2, Bcl-x(L) and NFkappaB, in a cell type-specific manner. Moreover, up regulation or down regulation of the same gene product can occur in a cell type-dependent manner following stimulation by glucocorticoids. This phenomenon is probably due to composite regulatory cross-talk among multiple nuclear coactivators or corepressors, which mediate the transcriptional regulation of the genes, by their interaction with the glucocorticoid receptor (GR). These observations suggest that the anti-inflammatory action of glucocorticoids is exerted by two complementary mechanisms: on the one hand, they induce death of the cells that provoke the inflammation, and on the other hand, they protect the resident cells of the inflamed tissue by arresting apoptotic signals.

Rifampicin inhibits CD95-mediated apoptosis of Jurkat T cells via glucocorticoid receptors by modifying the expression of molecules regulating apoptosis

Rifampicin and its analogues are increasingly used in the treatment and prophylaxis of mycobacterial infections. Recently, it has been demonstrated that rifampicin binds to and activates glucocorticoid receptors (GR). Glucocorticoids may inhibit or promote apoptosis in various cell types. Therefore, we investigated the effect of rifampicin on anti-CD95-induced apoptosis in Jurkat T cells. Rifampicin, in a concentration-dependent manner, inhibited anti-CD95-induced apoptosis. Furthermore, rifampicin down-regulated the expression of Bax and CD95L and up-regulated the expression of Bcl-2, Bcl-xL, and Flice-inhibitory protein-L (FLIPL); however, rifampicin had no effect on CD95 or XIAP expression. Rifampicin did not inhibit the binding of anti-CD95 monoclonal antibody to CD95 receptor. A GR-specific antagonist RU480 reversed the inhibition of apoptosis by rifampicin. Furthermore, rifampicin failed to inhibit anti-CD95-induced apoptosis in a dominant negative IKBalpha (IKBaM) Jurkat T cells. Taken together, these findings suggest that rifampicin inhibits anti-CD95-induced apoptosis in Jurkat T cells by modulating the expression of various molecules regulating apoptosis and its effect appears to be mediated via GR and at least in part through NF-kappaB signaling pathway.

The in-vitro characterization of induced apoptosis in placental cytotrophoblasts and syncytiotrophoblasts

Placental trophoblasts undergo apoptosis as part of normal epithelial turnover and placental ageing. Classically, the induction of apoptosis in in vitro preparations has utilized the cytokines TNFalpha and IFNgamma and has been measured using the TUNEL technique. The aim of this study was to compare apoptotic susceptibility of mononucleated and differentiated trophoblasts using a range of cytotoxic agents. To achieve this, an in vitro model of syncytialization was used, along with isolated placental cytotrophoblasts and an extravillous cytotrophoblast derived cell line (SGHPL-4). Cytotrophoblasts from term placentae (n=12), syncytiotrophoblasts (n=12) and SGHPL-4s (n=8) were cultured under reduced oxygen or with TNFalpha/IFNgamma, dexamethasone or staurosporine. Apoptosis assessments were made using TUNEL, Annexin V binding, fluorescence microscopy and ATP/ADP measurements. Each cytotoxic agent increased apoptosis in all three cell populations. For untreated cells, cytotrophoblasts showed the greatest levels of apoptosis in culture. With stimulation, these levels were significantly elevated using dexamethasone, TNFalpha/IFNgamma and staurosporine and further raised under hypoxic conditions. SGHPL-4 cells showed similar trends to those of cytotrophoblasts, however the syncytiotrophoblasts, although responsive to dexamethasone and TNFalpha/IFNgamma, showed lower levels of apoptosis with staurosporine and hypoxia. ADP : ATP measurements gave similar results to the other techniques and ratios of less than 1.0 were correlated with Annexin V measurements on the flow cytometer (P< 0.001). The typical morphological features of apoptosis i.e. chromatin margination, membrane blebbing and apoptotic body formation were detected in cytotrophoblasts and SGHPL-4 cells. However, only chromatin condensation could be recognized in syncytiotrophoblast preparations. Necrotic cell numbers were also increased under all cytotoxic conditions. Although elevated with dexamethasone, staurosporine and hypoxia, these levels were markedly raised in cytotrophoblasts and SGHPL-4 cells following incubations with TNFalpha/IFNgamma. These observations show variations in apoptosis between mononuclear trophoblasts and differentiated multinucleated syncytiotrophoblasts. Differential effects of stimuli may suggest disparate apoptotic pathways. These variations may reflect functional differences between placental cellular and syncytial components and may highlight the importance of exogenous stimulation in various stages of placental development.

Prednisolone sodium succinate down-regulates BSAP/Pax5 and causes a growth arrest in the Nalm6 pre-B cell line

Glucocorticoids (GCs) induce growth arrest and apoptosis of B lineage cells, especially pre-B and immature B cells, but little is known about this mechanism. Since B cell-specific activator protein (BSAP) encoded by the Pax5 gene is an essential transcription factor for B-cell proliferation, we have investigated the effect of prednisolone sodium succinate (Pss) on BSAP expression in several human leukemic B lineage cell lines. Pss caused growth arrest of Nalm6 (pre-B) cells, but this is not the case for 207 (pro-B) and Raji (mature B) cells. In Nalm6 cells, the growth rate and the amount of BSAP bound to its recognition sequence decreased in proportion to the Pss dose. Pss also reduced the expression level of BSAP as well as of Pax5 mRNA. These data suggest that the suppression of Pax5/BSAP may be involved in the GCs-induced growth arrest of pre-B cells.

Immune aberrations in B and T lymphocytes derived from chronic urticaria patients

To investigate the pathophysiology of chronic urticaria (CU) in light of the abundant evidences that it is an autoimmune disease and to define some cellular markers in B/T lymphocytes that could be of pathogenic significance, we investigated 14 patients suffering from CU, compared to 7 contact dermatitis patients and 10 normal control individuals. We tested the expression of CD5, B7.1 (CD80), CD23, and CD25 on B cells and of CD(40L)) and CD25 on T cells from all studied individuals. We also tested B cell proliferation upon their activation followed by dexamethazone induced inhibition of proliferation. The expression of bcl-2 protein in activated lymphocytes from normal individuals was compared to that of contact dermatitis and CU patients. CD(40L) expression was found significantly higher on in (vitro activated CD3 [with phorbol myristate acetate (PMA) and ionomycine Ca2+ at 12 hr of culture] from CU patients compared to that of contact dermatitis and normal individuals. Whereas the proliferation of activated B cells from CU patients was higher, dexamethazone-induced inhibition of B cell proliferation was found statistically similar in both groups yet lower in B cells from most severe CU patients. We demonstrate a higher bcl-2 expression in activated B and T lymphocytes of severe CU patients compared to that of moderate CU and both contact dermatitis and normal individuals. The increased expression of CD(40L) on activated T cells might play a role in the polyclonal increased B cell proliferation of CU patients. This increased proliferation accompanies the finding that activated B and T lymphocytes from these patients demonstrate increased bcl-2 expression. The resistance of some B cells to dexamethazone-induced inhibition of proliferation encourages us to investigate the possibility that B cells from some CU patients might develop rescue mechanisms from activated cell death. These findings provide further evidence that CU is indeed an autoimmune disease, although its precise nature has yet to be fully elucidated.

Glucocorticoids promote the proliferation and antagonize the retinoic acid–mediated growth suppression of Epstein-Barr virus–immortalized B lymphocytes

Glucocorticoids are able to release Epstein-Barr virus–immortalized (EBV-immortalized) lymphoblastoid B cell lines (LCLs) from the persistent growth arrest induced in these cells by retinoic acid (RA). Moreover, physiologic concentrations of glucocorticoids efficiently antagonized LCL growth inhibition induced by 13-cis-RA; 9-cis-RA; all-trans-RA; and Ro 40-6055, an RA  receptor (RAR) selective agonist. RAR expression levels, however, were not affected by glucocorticoids. Glucocorticoids, but not other steroid hormones, directly promote LCL proliferation, a phenomenon that was mainly mediated by down-regulation of the cyclin-dependent kinase (CDK) inhibitor p27Kip-1. Moreover, glucocorticoids contrasted the up-regulation of p27Kip-1, which was underlying the RA-induced LCL growth arrest, thereby indicating that glucocorticoids and RA signalings probably converge on p27Kip-1. Both antagonism of RA-mediated growth inhibition and promotion of LCL proliferation were efficiently reversed by the glucocorticoid receptor (GR) antagonist RU486, indicating that all of these effects were mediated by GR. Of note, RU486 also proved to be effective in vivo and, in mice, was able to significantly inhibit the growth of untreated LCLs as well as LCLs growth-arrested by RA in vitro. These findings provide a rational background to further evaluate the possible role of glucocorticoids in the pathogenesis of EBV-related lymphoproliferations of immunosuppressed patients. Moreover, GR antagonists deserve further consideration for their possible efficacy in the management of these disorders, and the use of schedules, including both RA and a GR antagonist, may allow a more thorough evaluation of the therapeutic potential of RA in this setting.

Glucocorticoids promote the proliferation and antagonize the retinoic acid–mediated growth suppression of Epstein-Barr virus–immortalized B lymphocytes

Glucocorticoids are able to release Epstein-Barr virus–immortalized (EBV-immortalized) lymphoblastoid B cell lines (LCLs) from the persistent growth arrest induced in these cells by retinoic acid (RA). Moreover, physiologic concentrations of glucocorticoids efficiently antagonized LCL growth inhibition induced by 13-cis-RA; 9-cis-RA; all-trans-RA; and Ro 40-6055, an RA  receptor (RAR) selective agonist. RAR expression levels, however, were not affected by glucocorticoids. Glucocorticoids, but not other steroid hormones, directly promote LCL proliferation, a phenomenon that was mainly mediated by down-regulation of the cyclin-dependent kinase (CDK) inhibitor p27Kip-1. Moreover, glucocorticoids contrasted the up-regulation of p27Kip-1, which was underlying the RA-induced LCL growth arrest, thereby indicating that glucocorticoids and RA signalings probably converge on p27Kip-1. Both antagonism of RA-mediated growth inhibition and promotion of LCL proliferation were efficiently reversed by the glucocorticoid receptor (GR) antagonist RU486, indicating that all of these effects were mediated by GR. Of note, RU486 also proved to be effective in vivo and, in mice, was able to significantly inhibit the growth of untreated LCLs as well as LCLs growth-arrested by RA in vitro. These findings provide a rational background to further evaluate the possible role of glucocorticoids in the pathogenesis of EBV-related lymphoproliferations of immunosuppressed patients. Moreover, GR antagonists deserve further consideration for their possible efficacy in the management of these disorders, and the use of schedules, including both RA and a GR antagonist, may allow a more thorough evaluation of the therapeutic potential of RA in this setting.

Heroin-induced alterations in leukocyte numbers and apoptosis in the rat spleen

The present study assessed the effects of acute heroin treatment on the cellularity of the rat spleen and the rate of splenocyte death by necrosis or apoptosis. The results showed that 1 h after a single injection of heroin, the total number of leukocytes in the spleen was decreased in a dose-dependent manner. Prior injection of naltrexone completely blocked heroin's effect, and the heroin-induced decrease in splenic leukocytes was not associated with a heroin-induced increase in circulating leukocytes. A 1-h exposure to heroin did not increase levels of lactate dehydrogenase, a cytosolic enzyme, in supernatants of splenic mononuclear cells cultured for 45 min or 24 h, suggesting that heroin does not increase necrotic death in the spleen. In contrast, a 1-h heroin treatment did increase the percentage of Annexin V(+) cells in 0- and 24-h cultures of splenic mononuclear cells, indicating that heroin increases apoptotic death in the spleen. A 3-h exposure to heroin also produced a significant increase in apoptosis in the spleen. DNA fragmentation, a marker of cells in late stages of apoptosis, could not be detected in fresh splenocytes, but was evident in 24-h cultures of splenic mononuclear cells from saline- and heroin-treated rats. These results demonstrate that a single administration of heroin produces a decrease in the number of splenic leukocytes and an increase in the apoptotic death of splenic mononuclear cells.

Effect of synthetic lipids on apoptosis and expression of alkaline phosphatase in B-lymphocytes: influence on lipopolysaccharide action

Synthetic lipids were examined for their ability to mimic or to antagonize lipopolysaccharide (LPS) action in murine B-lymphocytes. Several recognized effects of LPS were analyzed: prevention of spontaneous apoptosis, expression of alkaline phosphatase (ALP) and stimulation of proliferation. Three synthetic lipids were used for that purpose: a lipopeptide (compound MTPP) which carries non-hydroxylated fatty acids, and is thus unrelated to LPS, and two glycolipids with hydroxylated fatty acids (compounds D2 and PPDm2-B), structurally related to the lipid A region of enterobacterial and Rhodopseudomonas LPS, respectively. We found that the ability of these lipids to induce LPS-like responses was not correlated with their structural analogy with LPS. Thus, the lipopeptide, MTPP, mimicked LPS in the three activities, whereas the glycolipid, D2, did not. In contrast, the ability of synthetic lipids to block LPS effects was correlated with their structural analogy with LPS. We thus observed that compound D2 selectively blocked LPS-induced ALP expression and that PPDm2-B selectively inhibited LPS-induced prevention of apoptosis. These synthetic lipids could therefore be useful for studying the LPS-mediated signals involved in B-cell activation and apoptosis.

Specific dual effect of cycloheximide on B lymphocyte apoptosis: involvement of CPP32/caspase-3

Cycloheximide (CHX) is known to stimulate or to prevent apoptosis, according to the cell type used. We found that CHX, in a dose-dependent way, exerted the two opposite effects in B lymphocytes. CHXhigh (2.5 microg/mL) inhibited protein synthesis (>90%) and greatly increased B cell apoptosis but failed to prevent apoptosis induction by dexamethasone (DEX) or dibutyryl-cAMP (dbcAMP), which is in opposition with CHX activity in thymocytes. On the contrary, CHXlow (0.05 microg/mL), modestly inhibited protein synthesis (<15%) and reduced spontaneous as well as drug-induced apoptosis and further augmented the protection conferred by interleukin-4 or lipopolysaccharide. To examine the role of caspases in CHX effects, we used the broad spectrum peptide caspase inhibitor Z-VAD-fmk: it totally abrogated spontaneous as well as drug- and CHXhigh-induced cell death. Apoptosis was associated with CPP32/caspase-3 activation, since cleavage of CPP32/caspase-3 and caspase-3 activity were increased by DEX, dbcAMP as well as by CHXhigh treatment. Meanwhile, caspase-3 activity was reduced by CHXlow treatment. Therefore, CHX exerts opposite effects on B lymphocyte apoptosis which are associated with a dual action on caspase-3 activation.