Blockade of CD40-CD154 pathway interactions suppresses ectopic lymphoid structures and inhibits pathology in the NOD/ShiLtJ mouse model of Sjögren's syndrome.

OBJECTIVE: To examine the role of CD40-CD154 costimulation and effects of therapeutic pathway blockade in the non-obese diabetic (NOD/ShiLtJ) model of Sjögren's syndrome (SS). METHODS: We assessed leucocyte infiltration in salivary glands (SGs) from NOD/ShiLtJ mice by immunohistochemistry and examined transcriptomics data of SG tissue from these animals for evidence of a CD40 pathway gene signature. Additionally, we dosed MR1 (anti-CD154 antibody) in NOD mice after the onset of SS-like disease and examined the effects of MR1 treatment on sialadenitis, autoantibody production, SG leucocyte infiltration, gene expression downstream of CD40 and acquaporin 5 (AQP5) expression. RESULTS: We could detect evidence of CD40 expression and pathway activation in SG tissue from NOD mice. Additionally, therapeutic treatment with MR1 suppressed CD40 pathway genes and sialadenitis, inhibited ectopic lymphoid structure formation and autoantibody production, as well as decreased the frequency of antibody-secreting cells in SGs but had minimal effects on AQP5 expression in NOD/ShiLtJ SGs. CONCLUSION: CD40-CD154 interactions play an important role in key pathological processes in a mouse model of SS, suggesting that blockade of this costimulatory pathway in the clinic may have beneficial therapeutic effects in patients suffering from this autoimmune exocrinopathy.

A pilot study of high-dose intravenous immunoglobulin 5% for autism: Impact on autism spectrum and markers of neuroinflammation.

Research has shown that a subset of the autism spectrum disorder (ASD) population presents with immune dysregulation. To explore this topic further, we investigated the efficacy and tolerability of intravenous immunoglobulin (IVIG) infusion in children with ASD. In this study, participants were recruited based on a diagnosis of autistic disorder, Asperger's disorder, or pervasive developmental disorder not otherwise specified. Participants also showed evidence of immune dysfunction based on abnormal levels of specific biomarkers, including CD40 ligand (CD154), lymphocyte stimulation, and T or B cell dysfunction. Of 17 screened patients, 14 completed the trial and received IVIG treatment (1 g/kg dose) for ten 21-day treatment cycles. The primary endpoint was disease improvement assessed using standardized cognitive and behavioral tests (Children's Communication Checklist [CCC-2], Social Responsiveness Scale [SRS], Aberrant Behavior Checklist [ABC], Clinical Global Impressions-Severity [CGI-S] and -Improvement [CGI-I], Autism Diagnostic Observation Schedule [ADOS], and Peabody Picture Vocabulary Test [PPVT]). Secondary endpoints included experimental biomarkers such as CD154, toll-like receptor-4, memory B cells, FOXP3, and lymphocyte stimulation. Significant improvements from baseline to study endpoint were observed in several subscales of the CCC-2, SRS, CGI-I, CGI-S, and ADOS, including Associated Maladaptive Behaviors (P ≤ .043), Reciprocal Social Interaction (P = .015), Communication (P < .001), and Stereotyped Behaviors and Repetitive Interests (P ≤ .013). Statistically significant reductions were also seen in numerous secondary outcomes of immunological biomarkers indicative of neuroinflammation. IVIG was well tolerated; no subjects withdrew due to an adverse event, and clinical data showed no evidence of thromboembolic events. Autism Res 2018, 11: 421-433. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Since research has demonstrated a link between autism spectrum disorder (ASD) and immune dysfunction, this study investigated the efficacy and tolerability of intravenous immunoglobulin (IVIG) infusion in children with ASD. Fourteen patients received IVIG treatment and were assessed using standardized cognitive and behavioral tests. Following treatment with IVIG, significant improvement was observed across several subscales of the clinical tests and significant reductions were seen in the markers of neuroinflammation. These data suggest that inflammatory etiologies may play a role in select cases of autism, and IVIG treatment may exert a positive impact on behaviors and markers of inflammation in ASD.

Prospects for modulating the CD40/CD40L pathway in the therapy of the hyper-IgM syndrome.

The critical role of the CD40/CD40L pathway in B-cell proliferation, immunoglobulin (Ig) isotype switching and germinal center formation has been studied and described extensively in previous literature. Interruption of the CD40/CD40L signal causes hyper-IgM (HIGM) syndrome, which has been classified and recognized as a group of rare inherited immune deficiency disorders. Defects in CD40 and CD40L interactions or in downstream signaling molecules, including activation-induced cytidine deaminase, uracyl-DNA-glycosylase, NF-κB and DNA repair enzymes, result in an increased level of serum IgM and a significantly decreased or absent level of IgA, IgG and IgE that is accompanied by severe recurrent infections and autoimmune diseases. Many genetic defects in HIGM have been identified and, as a result, it is possible for patients to be definitively diagnosed by gene sequencing and to delineate the immunological features of the patients. Modifying the CD40/CD40L signaling pathway may offer the possibility of restoring the normal serum Ab production and curing the immunodeficiency. Hematopoietic stem cell transplantation has achieved a high rate of success using a sibling donor. In addition, successful examples of treating other immunodeficiencies using gene therapy indicated that there was a possibility of eradicating HIGM with this approach. In this review, we summarize the current drugs and a variety of therapeutic approaches for the treatment of the HIGM syndrome by interfering with the defective CD40/CD40L pathway.

Repeated administration of dapirolizumab pegol in a randomised phase I study is well tolerated and accompanied by improvements in several composite measures of systemic lupus erythematosus disease activity and changes in whole blood transcriptomic profiles.

OBJECTIVES: Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease associated with diffuse immune cell dysfunction. CD40-CD40 ligand (CD40L) interaction activates B cells, antigen-presenting cells and platelets. CD40L blockade might provide an innovative treatment for systemic autoimmune disorders. We investigated the safety and clinical activity of dapirolizumab pegol, a polyethylene glycol conjugated anti-CD40L Fab' fragment, in patients with SLE. METHODS: This 32-week randomised, double-blind, multicentre study (NCT01764594) evaluated repeated intravenous administration of dapirolizumab pegol in patients with SLE who were positive for/had history of antidouble stranded DNA/antinuclear antibodies and were on stable doses of immunomodulatory therapies (if applicable). Sixteen patients were randomised to 30 mg/kg dapirolizumab pegol followed by 15 mg/kg every 2 weeks for 10 weeks; eight patients received a matched placebo regimen. Randomisation was stratified by evidence of antiphospholipid antibodies. Patients were followed for 18 weeks after the final dose. RESULTS: No serious treatment-emergent adverse events, thromboembolic events or deaths occurred. Adverse events were mild or moderate, transient and resolved without intervention. One patient withdrew due to infection.Efficacy assessments were conducted only in patients with high disease activity at baseline. Five of 11 (46%) dapirolizumab pegol-treated patients achieved British Isles Lupus Assessment Group-based Composite Lupus Assessment response (vs 1/7; 14% placebo) and 5/12 (42%) evaluable for SLE Responder Index-4 responded by week 12 (vs 1/7; 14% placebo). Mechanism-related gene expression changes were observed in blood RNA samples. CONCLUSIONS: Dapirolizumab pegol could be an effective biological treatment for SLE. Further studies are required to address efficacy and safety. TRIAL REGISTRATION NUMBER: NCT01764594.

Rosuvastatin Attenuates CD40L-Induced Downregulation of Extracellular Matrix Production in Human Aortic Smooth Muscle Cells via TRAF6-JNK-NF-κB Pathway.

CD40L and statins exhibit pro-inflammatory and anti-inflammatory effects, respectively. They are both pleiotropic and can regulate extracellular matrix (ECM) degeneration in an atherosclerotic plaque. Statins can decrease both the CD40 expression and the resulting inflammation. However, the effects of CD40L and stains on atherosclerotic plaque ECM production and the underlying mechanisms are not well established. Moreover, prolyl-4-hydroxylase α1 (P4Hα1) is involved in collagen synthesis but its correlations with CD40L and statins are unknown. In the present study, CD40L suppressed P4Hα1 expression in human aortic smooth muscle cells (HASMCs) in a dose- and time-dependent manner, with insignificant changes in MMP2 expression and negative enzymatic activity of MMP9. CD40L increased TRAF6 expression, JNK phosphorylation, NF-κB nuclear translocation as well as DNA binding. Furthermore, silencing TRAF6, JNK or NF-κB genes abolished CD40L-induced suppression of P4Hα1. Lower NF-κB nuclear import rates were observed when JNK or TRAF6 silenced HASMCs were stimulated with CD40L compared to HASMCs with active JNK or TRAF6. Together, these results indicate that CD40L suppresses P4Hα1 expression in HASMCs by activating the TRAF6-JNK- NF-κB pathway. We also found that rosuvastatin inhibits CD40L-induced activation of the TRAF6-JNK- NF-κB pathway, thereby significantly rescuing the CD40L stimulated P4Hα1 inhibition. The results from this study will help find potential targets for stabilizing vulnerable atherosclerotic plaques.

Rapamycin and CTLA4Ig synergize to induce stable mixed chimerism without the need for CD40 blockade.

The mixed chimerism approach achieves donor-specific tolerance in organ transplantation, but clinical use is inhibited by the toxicities of current bone marrow (BM) transplantation (BMT) protocols. Blocking the CD40:CD154 pathway with anti-CD154 monoclonal antibodies (mAbs) is exceptionally potent in inducing mixed chimerism, but these mAbs are clinically not available. Defining the roles of donor and recipient CD40 in a murine allogeneic BMT model, we show that CD4 or CD8 activation through an intact direct or CD4 T cell activation through the indirect pathway is sufficient to trigger BM rejection despite CTLA4Ig treatment. In the absence of CD4 T cells, CD8 T cell activation via the direct pathway, in contrast, leads to a state of split tolerance. Interruption of the CD40 signals in both the direct and indirect pathway of allorecognition or lack of recipient CD154 is required for the induction of chimerism and tolerance. We developed a novel BMT protocol that induces mixed chimerism and donor-specific tolerance to fully mismatched cardiac allografts relying on CD28 costimulation blockade and mTOR inhibition without targeting the CD40 pathway. Notably, MHC-mismatched/minor antigen-matched skin grafts survive indefinitely whereas fully mismatched grafts are rejected, suggesting that non-MHC antigens cause graft rejection and split tolerance.

The effect of mycophenolic acid on epigenetic modifications in lupus CD4+T cells.

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease involving multiple organs and characterized by overproduction of autoantibodies and T and B cell abnormalities. The treatment for SLE has been restricted to immunosuppressants and corticosteroids. Mycophenolate mofetil (MMF), as a relatively new immunosuppressant, is now widely used in the treatment of SLE patients, particularly those with nephritis. However, it is unclear whether mycophenolic acid (MPA) could modulate the reported disorders of epigenetic status in CD4(+)T cells from SLE patients. In this study, we demonstrated that MPA can upregulate the histone H3/H4 global acetylation status by regulating HATs and HDACs in lupus CD4(+)T cells. Furthermore, we found that MPA also affected the histone H4 acetylation and histone H3K4 tri-methylation levels in CD40L promoter region that inhibited the expression of CD40L. These findings indicate the potential epigenetic mechanism of therapeutic effects of MPA in SLE.

Increased soluble CD154 (CD40 ligand) levels in xenograft recipients correlate with the development of de novo anti-pig IgG antibodies.

BACKGROUND: De novo anti-pig antibodies are associated with acute humoral xenograft rejection. We explored the relative efficacy of CD40/CD154-pathway blockade versus CD28/B7-pathway blockade in the prevention of de novo anti-pig IgG antibodies in xenograft recipients. METHODS: After α1,3-galactosyltransferase gene-knockout pig artery patch xenotransplantation, recipient baboons received no immunosuppression (IS; n=3), or anti-CD154mAb-based (n=5) or CTLA4-Ig-based (n=5) IS. CD4 T-cell and CD20 B-cell numbers in blood were determined. Serum anti-pig IgG antibodies and serum soluble (s)CD154 levels were measured. In lymph nodes, germinal center formation was examined and numbers of proliferating cells were evaluated by Ki-67 staining. RESULTS: After transplantation, with no IS, CD4 T-cell and CD20 B-cell numbers were increased, but were reduced by IS.In lymph nodes, with no IS, there was enhanced germinal center formation, which was significantly reduced by anti-CD154mAb-based (P<0.01) or CTLA4-Ig-based (P<0.01) IS. With no IS, there was strong expression of Ki-67-positive cells in lymph nodes, indicating extensive cellular proliferation. Ki-67-positive cells were significantly reduced by anti-CD154mAb-based (P<0.05) but not by CTLA4-Ig-based IS. High mean levels of sCD154 were detected with no IS (3324 pg/mL), in comparison to naive control baboons (214 pg/mL). With anti-CD154mAb-based IS, sCD154 was reduced to less than 1 pg/mL and with CTLA4-Ig-based IS to 65 pg/mL. There was significant positive correlation between sCD154 and anti-pig IgG levels (P<0.01). CONCLUSIONS: In xenograft recipients, anti-CD154mAb may reduce class-switching of anti-pig antibodies by binding both T-cell surface CD154 and circulating sCD154, thus preventing subsequent stimulation of B cells and activation of lymphoid follicles in secondary lymphoid tissues.

Protective mechanisms of guanosine from Solanum lycopersicum on agonist-induced platelet activation: role of sCD40L.

In the past 30 years, only three natural products have been sources of new drugs with antiplatelet activity. In this study, we have demonstrated for the first time that guanosine from Solanum lycopersicum possesses antiplatelet (secretion, spreading, adhesion and aggregation) activity in vitro and inhibition of platelet inflammatory mediator of atherosclerosis (sCD40L). According to ADP-induced platelet aggregation inhibiting, the total extract residue was fractionated by liquid chromatography/phase separation, affording an aqueous fraction. This fraction was subjected to repeated permeation over Sephadex LH-20 and semi-preparative TLC. The isolated compound finally obtained was identified as guanosine on the basis of its UV-spectra, HPLC and 1H-NMR data. Guanosine concentration dose-dependently (1 to 4 mmol/L) inhibited platelet secretion and aggregation induced by ADP and collagen. Spread of human platelets on collagen in the presence of guanosine was fully inhibited. After incubation of whole blood with guanosine, the platelet adhesion and aggregation under flow conditions was inhibited concentration dependently (0.2 to 2 mmol/L). At the same concentrations that guanosine inhibits platelet aggregation, levels of sCD40L were significantly decreased. Guanosine is thus likely to exert significant protective effects in thromboembolic-related disorders by inhibiting platelet aggregation.

Effect of hydroxychloroquine treatment on pro-inflammatory cytokines and disease activity in SLE patients: data from LUMINA (LXXV), a multiethnic US cohort.

OBJECTIVE: We sought to determine the effect of hydroxychloroquine therapy on the levels proinflammatory/prothrombotic markers and disease activity scores in patients with systemic lupus erythematosus (SLE) in a multiethnic, multi-center cohort (LUMINA). METHODS: Plasma/serum samples from SLE patients (n = 35) were evaluated at baseline and after hydroxychloroquine treatment. Disease activity was assessed using SLAM-R scores. Interferon (IFN)-α2, interleukin (IL)-1ß, IL-6, IL-8, inducible protein (IP)-10, monocyte chemotactic protein-1, tumor necrosis factor (TNF)-α and soluble CD40 ligand (sCD40L) levels were determined by a multiplex immunoassay. Anticardiolipin antibodies were evaluated using ELISA assays. Thirty-two frequency-matched plasma/serum samples from healthy donors were used as controls. RESULTS: Levels of IL-6, IP-10, sCD40L, IFN-α and TNF-α were significantly elevated in SLE patients versus controls. There was a positive but moderate correlation between SLAM-R scores at baseline and levels of IFN-α (p = 0.0546). Hydroxychloroquine therapy resulted in a significant decrease in SLAM-R scores (p = 0.0157), and the decrease in SLAM-R after hydroxychloroquine therapy strongly correlated with decreases in IFN-α (p = 0.0087). CONCLUSIONS: Hydroxychloroquine therapy resulted in significant clinical improvement in SLE patients, which strongly correlated with reductions in IFN-α levels. This indicates an important role for the inhibition of endogenous TLR activation in the action of hydroxychloroquine in SLE and provides additional evidence for the importance of type I interferons in the pathogenesis of SLE. This study underscores the use of hydroxychloroquine in the treatment of SLE.

Impact of the CD40-CD40L dyad in Alzheimer's disease.

As the number of elderly individuals rises, Alzheimer's disease (AD), marked by amyloid-beta deposition, neurofibrillary tangle formation, and low-level neuroinflammation, is expected to lead to an ever-worsening socioeconomic burden. AD pathoetiologic mechanisms are believed to involve chronic microglial activation. This phenomenon is associated with increased expression of membrane-bound CD40 with its cognate ligand, CD40 ligand (CD40L), as well as increased circulating levels of soluble forms of CD40 (sCD40) and CD40L (sCD40L). Here, we review the role of this inflammatory dyad in the pathogenesis of AD. In addition, we examine potential therapeutic strategies such as statins, flavonoids, and human umbilical cord blood transplantation, all of which have been shown to modulate CD40-CD40L interaction in mouse models of AD. Importantly, therapeutic approaches focusing on CD40-CD40L dyad regulation, either alone or in combination with amyloid-beta immunotherapy, may provide for a safe and effective AD prophylaxis or treatment in the near future.

Abnormal high-expression of CD154 on T lymphocytes of ankylosing spondylitis patients is down-regulated by etanercept treatment.

The pathogenesis of ankylosing spondylitis (AS) still remains an enigma. Although some studies have indicated the importance of T-cells and proinflammatory cytokines in the pathogenesis of the AS, it is still unknown whether co-stimulatory molecule CD154 participates in the pathogenesis of AS and how its level changes during the anti-TNF-alpha treatment of AS. This study is performed to evaluate the expression of CD154 in peripheral blood T-lymphocytes of patients with AS and observe the change of CD154 in etanercept-treated AS patient. We collected the peripheral blood and clinical data from 66 AS, 30 rheumatoid arthritis (RA) patients, and 30 healthy controls. Thirty-nine active AS patients were enrolled in a randomized double-blind placebo-controlled trial. We followed up 37 cases that fulfilled the ASAS20 response criteria after they finished etanercept treatment till week 48. The percentage of CD3+CD154+ in peripheral blood lymphocytes was evaluated by flow cytometry. We found that CD154 expression in AS patients was significantly higher than that in healthy volunteers and RA patients (both P < 0.001). The expressions of CD154 in AS patients at active stage or with peripheral joint involvement were significantly higher than those at stable stage or with axial involvement alone (P = 0.005 and 0.044, respectively). The expression of CD154 decreased in AS patients treated with etanercept compared with patients treated with placebo at week 6 (P < 0.001). Compared with healthy volunteers, the expression of CD154 in 16 AS patients who relapsed after finishing etanercept treatment was elevated again (P = 0.012). These findings show that co-stimulatory molecule CD154 is overexpressed on T-lymphocytes in peripheral blood of AS patients and can be down-regulated by etanercept treatment, which suggest that CD154 might be involved in the inflammatory evolvement of AS and might be a potential biomarker to monitor AS disease activity and the effect of etanercept treatment.

Regulatory effect of FK506 on CD152 and PD-1 in the liver allorecipients.

AIM: We dynamically observed the expression of CD152 and PD-1 on T-cell surfaces in peripheral blood of liver allorecipients to explore the regulatory effect of FK506 on negative costimulatory molecules. METHODS: We evaluated 20 liver allorecipients, 19 end-stage liver disease patients, and 20 healthy volunteers for FK506 concentrations measured by an enzyme-multiplied immunoassay technique and flow cytometry to determine T-cell subsets as well as CD152 and PD-1 expression. RESULTS: After liver transplantation, the frequency of CD4+ T cells gradually decreased to significantly lower level than those in the disease controls (P < .05). CD8+ T cells in each treatment group were obviously higher than those in the disease controls (P < .05). The expression of CD152 on CD4+ and CD8+ T cells was greater than those in healthy controls (P < .05); and at 2 and 4 weeks, higher than those in disease controls (P < .05). The expression of PD-1 on CD4+ T cells from the 2 weeks after treatment was significantly greater than that in healthy controls (P < .05), and that on CD8+ T cells increased obviously from the 4 weeks compared with disease controls (P < .05). CONCLUSION: FK506 up-regulated the expression of CD152 and PD-1 on the T-cell surface inhibiting proliferation and activation of effector T cells, favoring the survival of allorecipients.

Impact of psoralen/UVA-treatment on survival, activation, and immunostimulatory capacity of monocyte-derived dendritic cells.

BACKGROUND: Extracorporeal Photopheresis (ECP) has been shown to be an effective treatment of graft-versus-host disease, solid organ graft rejection, and other T-cell-mediated diseases. The mechanisms of action of ECP include lymphocyte apoptosis, cytokine modulation, and the induction of regulatory T cells. It has been suggested that dendritic cells (DCs) are more resistant to ECP-induced apoptosis and might be directly modulated by ECP. We tested this hypothesis using in vitro Psoralen/UVA (PUVA) treatment as an in vitro model of ECP. METHODS: Monocyte-derived DCs (mo-DCs) were treated with 8-methoxypsoralen /UVA and analyzed for surface molecule expression, apoptosis markers, endocytosis, and migratory and immunostimulatory capacity. Mo-DC phenotype and cytokine secretion was tested after CD40L stimulation. Naive T cells stimulated with PUVA-treated mo-DCs were tested for Th1/Th2 cytokine secretion and associated chemokine receptor patterns. RESULTS: DCs underwent apoptosis after in vitro PUVA and in vivo ECP. In vitro, the induction of apoptosis was preceded by partial maturation of immature mo-DCs. PUVA-treated immature mo-DCs also exhibited enhanced migratory and immunostimulatory capacity. However, mo-DCs stimulation through CD40 ligation was abrogated and interleukin (IL)-12 secretion was abolished 24 hr after PUVA treatment. PUVA-treated mo-DCs skewed naive T cells toward a Th2 response as defined by increased IL-4, IL-10, and IL-13 and decreased interferon-gamma levels, and the expression of the Th2-associated chemokine receptors CCR4 and CCR10. The observed Th2 shift was partially reversed by exogenous IL-12. CONCLUSION: These data suggest that direct modulation of DC function as well as apoptosis contribute to the immunoregulatory effects of ECP.

S-nitroso-N-acetylcysteine (SNAC) prevents myocardial alterations in hypercholesterolemic LDL receptor knockout mice by antiinflammatory action.

We investigated the ability of S-nitroso-N-acetylcyseine (SNAC) to prevent structural and functional myocardial alterations in hypercholesterolemic mice. C57BL6 wild-type (WT) and LDL-R-/- male mice (S) were fed a standard diet for 15 days. LDL-R-/- mice (S) showed an 11% increase in blood pressure, 62% decrease in left atrial contractility, and lower CD40L and eNOS expression relative to WT. LDL-R-/- mice fed an atherogenic diet for 15 days (Chol) showed significant increased left ventricular mass compared to S, which was characterized by: (1) 1.25-fold increase in the LV weight/body weight ratio and cardiomyocyte diameter; (2) enhanced expression of the NOS isoforms, CD40L, and collagen amount; and (3) no alteration in the atrial contractile performance. Administration of SNAC to Chol mice (Chol + SNAC) (0.51 micromol/kg/day for 15 day, IP) prevented increased left ventricular mass, collagen deposit, NOS isoforms, and CD40L overexpression, but it had no effect on the increased blood pressure or atrial basal hypocontractility. Deletion of the LDL receptor gene in mice resulted in hypertension and a marked left atrial contractile deficit, which may be related to eNOS underexpression. Our data show that SNAC treatment has an antiinflammatory action that might contribute to prevention of structural and functional myocardial alterations in atherosclerotic mice independently of changes in blood pressure.

CD40-CD40 ligand interactions in human microglia induce CXCL8 (interleukin-8) secretion by a mechanism dependent on activation of ERK1/2 and nuclear translocation of nuclear factor-kappaB (NFkappaB) and activator protein-1 (AP-1).

CXCL8 is a CXC chemokine that recruits leukocytes to sites of inflammation. Expression of CXCL8 in the CNS has been demonstrated in neuroinflammatory diseases, including human immunodeficiency virus (HIV-1) encephalitis, but the mechanism of secretion of this chemokine is not fully understood. CD40 is a 50-kDa protein on the surface of microglia, and we have previously shown that it is increased in expression in HIV-1-infected brain tissue as well as by interferon-gamma (IFNgamma) in tissue culture. We examined the expression and regulation of CXCL8 in cultured human fetal microglia after ligation of CD40 with soluble trimeric CD40 ligand (sCD40L) as well as the expression of CXCL8 on microglia in HIV encephalitic brain tissue sections. Treatment of cultured microglia with IFNgamma + sCD40L resulted in significant induction of CXCL8. This expression was mediated by activation of the ERK1/2 MAPK pathway, as demonstrated by ELISA and Western blot using a specific inhibitor (U0126). Gel shift analyses demonstrated that NFkappaB and AP-1, but not C/EBPbeta, mediate microglial CXCL8 production. We also found increased colocalization of CXCL8 with CD68/CD40-positive cells in HIV encephalitic brain tissue compared with HIV-infected nonencephalitic and normal tissue. Thus, CD40-CD40L interactions facilitate chemokine expression, leading to the influx of inflammatory cells into the CNS. These events can lead to the pathology that is associated with neuroinflammatory diseases.

Rosiglitazone produces a greater reduction in circulating platelet activity compared with gliclazide in patients with type 2 diabetes mellitus--an effect probably mediated by direct platelet PPARgamma activation.

AIMS: Type 2 diabetes mellitus (T2DM) is associated with enhanced platelet activation. We conducted a randomised double-blind study to compare the effects of combination metformin and rosiglitazone or metformin and gliclazide therapy on platelet function in persons with T2DM. METHODS: Fifty subjects on metformin monotherapy received either rosiglitazone 4 mg or gliclazide 80 mg. HbA1c, HOMA-R, markers of platelet activation, inflammation, endothelial activation and oxidative stress were measured at baseline and after 24 weeks of treatment. Separate in vitro platelet function studies were conducted on platelets pre-incubated with rosiglitazone and gliclazide. RESULTS: A significantly greater reduction in platelet aggregation was observed in the rosiglitazone treated group compared to gliclazide. HbA1c and markers of endothelial activation were reduced to a similar extent in both groups. A significant reduction in HOMA-R, markers of inflammation and oxidative stress was only observed with rosiglitazone. Reduction in platelet aggregation with rosiglitazone correlated with reduction in oxidative stress. In the in vitro study, rosiglitazone produced significantly greater reduction in platelet aggregation compared with gliclazide. CONCLUSION: Greater reduction in platelet activity observed with rosiglitazone may be related to reduced oxidative stress and a possible direct PPARgamma mediated effect on platelet function.

Heme oxygenase-1 improves the survival of discordant cardiac xenograft through its anti-inflammatory and anti-apoptotic effects.

HO-1 is a rate-limiting enzyme in hemoglobin metabolism, and exerts anti-inflammatory as well as anti-apoptotic effects. Previous studies have shown that expression of HO-1 can prolong the survival of concordant transplanted organs. However, little is known about the precise effect and mechanism of HO-1 in discordant xenotransplantation. In this study, we investigated the role of HO-1 in discordant cardiac xenotransplantation. First, HUVECs were used to assess the effect of HO-1 on TNF-alpha-induced apoptosis. Results showed that TNF-alpha induced apoptosis of HUVECs in a dose-dependent manner. Moreover, induction of HO-1 by hemin suppressed TNF-alpha-induced apoptosis. However, the anti-apoptotic action of HO-1 was reversed by SnPP. The up-regulation of HO-1 by hemin treatment significantly prolonged the survival time of discordant cardiac xenograft, greatly reduced the swelling and apoptosis of myocardial cells, interstitial edema, lymphocyte infiltration, and thrombus formation in small vessels. Furthermore, HO-1 overexpression significantly attenuated the serum level of xenoantibody IgM, tissue deposition of IgM and complement 3 (C(3)) in endangium. Finally, HO-1 mitigated CD40L transcription in the xenograft and recipient spleen. These results indicate that the up-regulation of HO-1 can improve the survival of discordant cardiac xenograft by inhibiting apoptosis and alleviating inflammation and thrombosis.

[Antiplatelet effects of micronized fenofibrate in subjects with dyslipidemia]. / Przeciwplytkowe dzialania fenofibratu mikronizowanego u osób z dyslipidemia.

INTRODUCTION: Fibrates produce additional actions such as reduction of inflammatory state, insulin resistance and activation of blood coagulation, along with stimulation of fibrinolysis. It is not known whether fibrates can attenuate platelet activation. OBJECTIVES: Evaluation of antiplatelet effects of fenofibrate in dyslipidemic subjects. PATIENTS AND METHODS: In 20 patients (15 males, 5 females) aged 40 to 70 years who had plasma triglicerydes >1.7 mmol/l and low-density lipoprotein (LDL) cholesterol >3.4 mmol/l without diabetes, we determined plasma levels of platelet markers, soluble CD40 ligand (sCD40L) and selectin P, both in peripheral blood and samples collected every 1 minute from sites of microvascular injury prior to and following a one-month administration of micronized fibrate (160 mg/d). Results. Neither of platelet activation markers was altered following fenofibrate. We identified 7 subjects who had a significant decrease (14-21%) in velocity of the sCD40L and selectin P release after fenofibrate (p < 0.05). This subgroup was characterized by increased body mass, and posttreatment greater reduction in triglycerides and increase in high-density lipoprotein (HDL) cholesterol (p < 0.05). A decrease in the release of platelet markers was associated with a greater posttreatment reduction in plasma 8-isoprostane levels (p = 0.006). CONCLUSIONS: In 1/3 of dyslipidemic subjects without diabetes, there is a decrease in platelet activation at the site of microvascular injury following a one-month administration of micronized fenofibrate. This effect can be found in individuals in whom the fibrate induced the greatest reduction in triglycerides and increase in HDL cholesterol. Moreover, antiplatelet effect of fenofibrate was associated with reduced oxidative stress.

Modulation of CLA, IL-12R, CD40L, and IL-2Ralpha expression and inhibition of IL-12- and IL-23-induced cytokine secretion by CNTO 1275.

Cytokines interleukin (IL)-12 and IL-23 are implicated in the pathogenesis of psoriasis. IL-12 causes differentiation of CD4+ T cells to interferon-gamma (IFN-gamma)-producing T helper 1 (Th1) cells, while IL-23 induces differentiation to IL-17-producing pathogenic Th17 cells. The effects of the monoclonal antibody to IL-12/23 p40 subunit (CNTO 1275) on IL-12 receptor (IL-12R) expression, markers associated with skin homing, activation, and cytokine secretion were investigated in vitro using human peripheral blood mononuclear cells (PBMCs) from healthy donors. PBMCs were activated in the presence or absence of recombinant human (rh) IL-12 or rhIL-23, with or without CNTO 1275. CNTO 1275 inhibited upregulation of CLA, IL-12R, IL-2Ralpha and CD40L expression and also inhibited IL-12- and IL-23-induced IFN-gamma, IL-17A, tumor necrosis factor (TNF)-alpha, IL-2, and IL-10 secretion. Thus, the therapeutic effect of CNTO 1275 may be attributed to the IL-12/23 neutralization, resulting in decreased expression of skin homing and activation markers, and IL-12- and IL-23-induced cytokine secretion.