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Objective: To investigate the hypothesis that selective inhibitors of nuclear export (SINE compounds), recently approved for treatment of refractory plasma cell (PC) malignancy, may have potential in the treatment of lupus. Methods: Female NZB/NZW mice were treated with the SINE compound KPT‐350 or vehicle control. Tissue specimens were harvested and analyzed by flow cytometry, using standard markers. Nephritis was monitored by determining the proteinuria score and by histologic analysis of kidney specimens. Serum anti–double‐stranded DNA (anti‐dsDNA) levels were measured by enzyme‐linked immunosorbent assay, and total numbers of IgG‐secreting and dsDNA‐specific antibody‐secreting cells were assessed by enzyme‐linked immunospot assay. Results: KPT‐350 abrogated murine lupus nephritis at both early and late stages of the disease and rapidly impaired generation of autoreactive PCs in germinal centers (GCs). SINE compounds inhibited the production of NF‐κB–driven homeostatic chemokines by stromal cells, altering splenic B and T cell strategic positioning and significantly reducing follicular helper T cell, GC B cell, and autoreactive PC counts. KPT‐350 also decreased levels of cytokines and chemokines involved in PC survival and recruitment in the kidney of lupus‐prone mice. Exportin 1, the target of SINE compounds, was detected in GCs of human tonsils, splenic B cells of lupus patients, and multiple B cell subsets in the kidneys of patients with lupus nephritis. Conclusion: Collectively, our results provide support for the therapeutic potential of SINE compounds, via their targeting of several molecular and cellular pathways critical in lupus pathogenesis, including autoantibody production by plasma cells. [ABSTRACT FROM AUTHOR]

Objective Despite considerable advances in the understanding of systemic lupus erythematosus (SLE), there is still an urgent need for new and more targeted treatment approaches. We previously demonstrated that small-molecule blockade of G protein βγ subunit (Gβγ) signaling inhibits acute inflammation through inhibition of chemokine receptor signal transduction. We undertook this study to determine whether inhibition of Gβγ signaling ameliorates disease in a mouse model of SLE. Methods Lupus-prone (NZB × NZW)F1 female mice were prophylactically or therapeutically treated with the small-molecule Gβγ inhibitor gallein. Tissue samples were analyzed by flow cytometry and immunohistochemistry. The development and extent of nephritis were assessed by monitoring proteinuria and by immunohistochemical analysis. Serum immunoglobulin levels were measured by enzyme-linked immunosorbent assay, and total IgG and anti-double-stranded DNA (anti-dsDNA) antibody-secreting cells were measured by enzyme-linked immunospot assay. Results Gallein inhibited accumulation of T cells and germinal center (GC) B cells in the spleen. Both prophylactic and therapeutic treatment reduced GC size, decreased antibody-secreting cell production in the spleen, and markedly decreased accumulation of autoreactive anti-dsDNA antibody-secreting cells in kidneys. Gallein also reduced immune complex deposition in kidneys. Finally, gallein treatment dramatically inhibited kidney inflammation, prevented glomerular damage, and decreased proteinuria. Mechanistically, gallein inhibited immune cell migration and signaling in response to chemokines in vitro, which suggests that its mechanisms of action in vivo are inhibition of migration of immune cells to sites of inflammation and inhibition of immune cell maturation. Conclusion Overall, these data demonstrate the potential use of gallein or novel inhibitors of Gβγ signaling in SLE treatment. [ABSTRACT FROM AUTHOR]

Objective To investigate the hypothesis that proteasome inhibition may have potential in the treatment of SLE, by targeting plasmacytoid dendritic cells (PDCs) and plasma cells, both of which are critical in disease pathogenesis. Methods Lupus-prone mice were treated with the nonselective proteasome inhibitors carfilzomib and bortezomib, the immunoproteasome inhibitor ONX 0914, or vehicle control. Tissue was harvested and analyzed by flow cytometry using standard markers. Nephritis was monitored by evaluation for proteinuria and by histologic analysis of kidneys. Serum anti-double-stranded DNA (anti-dsDNA) levels were measured by enzyme-linked immunosorbent assay (ELISA), and total IgG and dsDNA antibody-secreting cells (ASCs) by enzyme-linked immunospot assay. Human peripheral blood mononuclear cells or mouse bone marrow cells were incubated with Toll-like receptor (TLR) agonists and proteasome inhibitors, and interferon-α (IFNα) levels were measured by ELISA and flow cytometry. Results Early treatment of lupus-prone mice with the dual-targeting proteasome inhibitors carfilzomib or bortezomib or the immunoproteasome-specific inhibitor ONX 0914 prevented disease progression, and treatment of mice with established disease dramatically abrogated nephritis. Treatment had profound effects on plasma cells, with greater reductions in autoreactive than in total IgG ASCs, an effect that became more pronounced with prolonged treatment and was reflected in decreasing serum autoantibody levels. Notably, proteasome inhibition efficiently suppressed production of IFNα by TLR-activated PDCs in vitro and in vivo, an effect mediated by inhibition of both PDC survival and PDC function. Conclusion Inhibition of the immunoproteasome is equally efficacious as dual targeting agents in preventing lupus disease progression by targeting 2 critical pathways in disease pathogenesis, type I IFN activation and autoantibody production by plasma cells. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Although B cells are implicated in the pathogenesis of systemic lupus erythematosus, the role of B cell depletion (BCD) as a treatment is controversial, given the variable benefit in human disease. This study was undertaken to test the effects of BCD therapy in a murine lupus model to better understand the mechanisms, heterogeneity, and effects on disease outcomes. METHODS: (NZB x NZW)F(1) female mice with varying degrees of disease severity were treated with an anti-mouse CD20 (anti-mCD20) antibody (IgG2a), BR3-Fc fusion protein (for BAFF blockade), or control anti-human CD20 monoclonal antibody (approximately 10 mg/kg each). Tissue samples were harvested and analyzed by flow cytometry. The development and extent of nephritis were assessed by monitoring proteinuria (using a urine dipstick) and by immunohistochemical analysis of the kidneys. Serum immunoglobulin levels were measured by enzyme-linked immunosorbent assay. RESULTS: After a single injection of anti-mCD20, BCD was more efficient in the peripheral blood, lymph nodes, and spleen compared with the bone marrow and peritoneum of normal mice as well as younger mice with lupus. Since depletion of the marginal zone and peritoneal B cells was incomplete and variable, particularly in older mice with established nephritis, a strategy of sequential weekly dosing was subsequently used, which improved the extent of depletion. BAFF blockade further enhanced depletion in the spleen and lymph nodes. Early BCD therapy delayed disease onset, whereas BCD therapy in mice with advanced disease reduced the progression of nephritis. These effects were long-lasting, even after B cell reconstitution occurred, and were associated with a reduction in T cell activation but no significant change in autoantibody production. CONCLUSION: The lasting benefit of a short course of BCD therapy in lupus-prone mice with an intact immune system and established disease highlights the validity of this treatment approach. [ABSTRACT FROM AUTHOR]

Background: In dilated cardiomyopathy (DCM), eliminating or reducing extra-geometric burden to the myocardial cells would directly reduce myocardial wall stress leading to improved LV systolic performance. In acute experiments, we tested whether a passive non-blood contacting CardioClasp device, which employs two indenting bars to reshape the left ventricle (LV), could reduce extra-geometric burden, LV wall stress (LVWS) and improve LV systolic function and contractility without decreasing arterial blood pressure.Methods: In mongrel dogs (n = 5), 4 weeks of right ventricular pacing (210-220-230-240 ppm) induced DCM with severe heart failure. After placing the CardioClasp device, LV performance was evaluated immediately by measuring hemodynamics, echocardiography, and Sonometrics crystal data. Eleven sonometric crystals were placed into endocardial positions (8 in anterior, posterior, mid-anterior, mid-posterior, apex, base, free and septal wall) and in myocardial (2 as regional) and epicardial (1) positions to assess the LV end-systolic pressure-segment length relationships (ESPSR) and cross-sectional area (ESPAR) relationship.Results: CardioClasp decreased the LV end-diastolic anterior-posterior (A-P) dimensions at two levels (15% and 25%). With CardioClasp, LVWS decreased from 93.1 +/- 7.2 to 59.1 +/- 3.2 g/cm2 (P < 0.05) and fractional area of contraction (FAC) increased from 27.6 +/- 3.8 to 33.1 +/- 3.7% (P < 0.01). Peak LV and arterial pressures, LV +dP/dt, LV -dP/dt, and cardiac output were unaltered with CardioClasp. CardioClasp placement significantly increased the slopes of LV pressure versus anterior-posterior segment relationship from 7.3 +/- 0.6 to 15.8 +/- 1.8 mmHg/mm and septal-free wall segment relationship from 6.3 +/- 0.9 to 9.8 +/- 0.5 mmHg/mm. At both 15% and 25% LV A-P dimension reductions, the slopes of ESPAR showed significant steepening and increased from 10.1 +/- 0.7 (baseline) to 15.5 +/- 1.7 (15% reduction) and 19.0 +/- 1.4 mmHg/cm2 (25% reduction). The larger the reduction, the greater was the steepening of the slopes of ESPSR and ESPAR.Conclusions: CardioClasp reduced LV diameter and thereby decreased LVWS and increased FAC. CardioClasp was able to reshape the left ventricle, while preserving the contractile mass, which increased the slopes of ESPSR and ESPAR. This reshaping was associated with maintained systolic pressures, cardiac output, and increased contractility. [ABSTRACT FROM AUTHOR]

Abstract: Background: Although there is an increasing body of evidence for a deleterious effect of mismatched donor HLA antigens on the outcome of human cardiac transplantation, the role of anti-HLA lymphocytotoxic antibodies remains controversial. Thus, their appearance after cardiac transplantation has been associated with poor outcome by some groups; whereas others have reported them to be of no clinical significance. Furthermore, their presence prior to cardiac transplantation has also been the subject of similarly conflicting reports. The deleterious effect of such pre-existing antibodies has been predicted by a positive lymphocyte cross-match (LCM), which, for most patients awaiting renal transplantation and in many requiring a cardiac allograft, leads to cancellation of the operation. The reason for undertaking the current study was to test the hypothesis that the constraints which a positive LCM result impose in preventing renal transplantation may not apply to orthotopic heart transplantation (OHT). Patients and methods: Four sensitized patients underwent OHT across a positive prospective LCM. Three were females, and one of those females also underwent cadaveric renal transplantation at the time of OHT. All four patients received aggressive early post-transplant immunosuppressive therapy, which included plasmapheresis, intravenous immunoglobulin (IVIg), antiproliferative agents (cyclophosphamide, basiliximab) and cytokine down-regulators (calcineurin inhibitors, muromonab-CD3) and anticell antibodies (OKT3, ATG). They also received standard immunosuppressive therapy which included corticosteroids. Complement-dependent cytotoxicity (CDC) was used for the identification of anti-HLA lymphocytotoxic antibodies. Reactivity of the latter against more than 10% of a panel of well-characterized T cells was considered sensitization, and required LCM to be performed prospectively, which test was also performed using the CDC technique. Results: Three of the... [ABSTRACT FROM AUTHOR]

A correction to the article "Beneficial effect of novel proteasome inhibitors in murine lupus via dual inhibition of type I interferon and autoantibody-secreting cells," that was published in the February 2012 issue is presented.

Objective: Patients with antiphospholipid syndrome (APS) are at a high risk of developing atherosclerotic complications. Conversely, individuals with primary atherosclerosis have an increased prevalence of antiphospholipid antibodies (aPL) and antibodies to oxidized low-density lipoproteins (ox-LDL). Several studies suggest that these two antibody populations may in fact overlap, although it is unclear how aPL contribute to pathogenesis. In this study, we characterized an IgG monoclonal aPL and assessed its ability to modulate atherosclerosis in low-density lipoprotein receptor-deficient (LDLR(-/-)) mice., Methods: The cardiolipin-reactive monoclonal antibody FB1 was obtained from an (NZW x BXSB)F(1) mouse, a strain with APS features that make it prone to fatal myocardial infarctions. Using an enzyme-linked immunosorbent assay, we investigated the binding of this antibody to phospholipid and LDL antigens. We also passively administered FB1 to atherosclerosis-prone mice to determine its effect on atherogenesis., Results: In contrast to earlier studies of aPL that were specific for oxidized forms of LDL, FB1 cross-reacted with both native LDL and ox-LDL. In vivo, passive administration of FB1 significantly reduced plaque formation in atherosclerosis-prone LDLR(-/-) mice., Conclusion: These results indicate that some aPL may play a protective role in atherogenesis and suggest a novel approach to the prevention of atherosclerosis.