Low-dose FK506 blocks collar-induced atherosclerotic plaque development and stabilizes plaques in ApoE-/- mice

Improving Right Ventricular Function by Increasing BMP Signaling with FK506

Right Ventricular (RV) function is the predominant determinant of survival in patients suffering from pulmonary arterial hypertension (PAH). In pre-clinical models, pharmacological activation of bone morphogenetic protein (BMP) signaling with FK506 (Tacrolimus) improved RV function by decreasing RV afterload. FK506 therapy further stabilized three end-stage PAH patients. Whether FK506 has direct effects on the pressure overloaded RV is yet unknown. We hypothesized that increasing cardiac BMP signaling with FK506 improves RV structure and function in a model of fixed RV afterload after pulmonary artery banding (PAB). Direct cardiac effects of FK506 on the microvasculature and RV fibrosis were studied after surgical PAB in wildtype and heterozygous Bmpr2 mutant mice. Right ventricular function and strain were assessed longitudinally via cardiac magnetic resonance (CMR) imaging during continuous FK506 infusion. Genetic lineage tracing of endothelial cells (ECs) was performed to assess the contribution of ECs to fibrosis. Molecular mechanistic studies were performed in human cardiac fibroblasts (hCFs) and endothelial cells. In mice, low BMP signaling in the RV exaggerated PAB-induced RV fibrosis. FK506 therapy restored cardiac BMP signaling, reduced RV fibrosis in a BMP-dependent manner independent from its immunosuppressive effect, preserved RV capillarization and improved RV function and strain over the time-course of disease. Endothelial mesenchymal transition was a rare event and did not significantly contribute to cardiac fibrosis after PAB. Mechanistically, FK506 required ALK1 in hCFs as BMPR2 co-receptor to reduce TGFβ1-induced proliferation and collagen production. Our study demonstrates that increasing cardiac BMP signaling with FK506 improves RV structure and function independent from its previously described beneficial effects on pulmonary vascular remodeling.

Intranuclear interactomic inhibition of NF-κB suppresses LPS-induced severe sepsis

Suppression of nuclear factor-κB (NF-κB) activation, which is best known as a major regulator of innate and adaptive immune responses, is a potent strategy for the treatment of endotoxic sepsis. To inhibit NF-κB functions, we designed the intra-nuclear transducible form of transcription modulation domain (TMD) of RelA (p65), called nt-p65-TMD, which can be delivered effectively into the nucleus without influencing the cell viability, and work as interactomic inhibitors via disruption of the endogenous p65-mediated transcription complex. nt-p65-TMD effectively inhibited the secretion of pro-inflammatory cytokines, including TNF-α, IL-1β, or IL-6 from BV2 microglia cells stimulated by lipopolysaccharide (LPS). nt-p65-TMD did not inhibit tyrosine phosphorylation of signaling mediators such as ZAP-70, p38, JNK, or ERK involved in T cell activation, but was capable of suppressing the transcriptional activity of NF-κB without the functional effect on that of NFAT upon T-cell receptor (TCR) stimulation. The transduced nt-p65-TMD in T cell did not affect the expression of CD69, however significantly inhibited the secretion of T cell-specific cytokines such as IL-2, IFN-γ, IL-4, IL-17A, or IL-10. Systemic administration of nt-p65-TMD showed a significant therapeutic effect on LPS-induced sepsis model by inhibiting pro-inflammatory cytokines secretion. Therefore, nt-p65-TMD can be a novel therapeutics for the treatment of various inflammatory diseases, including sepsis, where a transcription factor has a key role in pathogenesis, and further allows us to discover new functions of p65 under normal physiological condition without genetic alteration.

Nuclear factor of activated T cells regulates neutrophil recruitment, systemic inflammation, and T-cell dysfunction in abdominal sepsis

The signaling mechanisms regulating neutrophil recruitment, systemic inflammation, and T-cell dysfunction in polymicrobial sepsis are not clear. This study explored the potential involvement of the calcium/calcineurin-dependent transcription factor, nuclear factor of activated T cells (NFAT), in abdominal sepsis. Cecal ligation and puncture (CLP) triggered NFAT-dependent transcriptional activity in the lung, spleen, liver, and aorta in NFAT-luciferase reporter mice. Treatment with the NFAT inhibitor A-285222 prior to CLP completely prevented sepsis-induced NFAT activation in all these organs. Inhibition of NFAT activity reduced sepsis-induced formation of CXCL1, CXCL2, and CXCL5 chemokines and edema as well as neutrophil infiltration in the lung. Notably, NFAT inhibition efficiently reduced the CLP-evoked increases in HMBG1, interleukin 6 (IL-6), and CXCL5 levels in plasma. Moreover, administration of A-285222 restored sepsis-induced T-cell dysfunction, as evidenced by markedly decreased apoptosis and restored proliferative capacity of CD4 T cells. Along these lines, treatment with A-285222 restored gamma interferon (IFN-γ) and IL-4 levels in the spleen, which were markedly reduced in septic mice. CLP-induced formation of regulatory T cells (CD4(+) CD25(+) Foxp3(+)) in the spleen was also abolished in A-285222-treated animals. All together, these novel findings suggest that NFAT is a powerful regulator of pathological inflammation and T-cell immune dysfunction in abdominal sepsis. Thus, our data suggest that NFAT signaling might be a useful target to protect against respiratory failure and immunosuppression in patients with sepsis.

FK506 activates BMPR2, rescues endothelial dysfunction, and reverses pulmonary hypertension

Dysfunctional bone morphogenetic protein receptor-2 (BMPR2) signaling is implicated in the pathogenesis of pulmonary arterial hypertension (PAH). We used a transcriptional high-throughput luciferase reporter assay to screen 3,756 FDA-approved drugs and bioactive compounds for induction of BMPR2 signaling. The best response was achieved with FK506 (tacrolimus), via a dual mechanism of action as a calcineurin inhibitor that also binds FK-binding protein-12 (FKBP12), a repressor of BMP signaling. FK506 released FKBP12 from type I receptors activin receptor-like kinase 1 (ALK1), ALK2, and ALK3 and activated downstream SMAD1/5 and MAPK signaling and ID1 gene regulation in a manner superior to the calcineurin inhibitor cyclosporine and the FKBP12 ligand rapamycin. In pulmonary artery endothelial cells (ECs) from patients with idiopathic PAH, low-dose FK506 reversed dysfunctional BMPR2 signaling. In mice with conditional Bmpr2 deletion in ECs, low-dose FK506 prevented exaggerated chronic hypoxic PAH associated with induction of EC targets of BMP signaling, such as apelin. Low-dose FK506 also reversed severe PAH in rats with medial hypertrophy following monocrotaline and in rats with neointima formation following VEGF receptor blockade and chronic hypoxia. Our studies indicate that low-dose FK506 could be useful in the treatment of PAH.

Inhibition of nuclear factor of activated T-cells (NFAT) suppresses accelerated atherosclerosis in diabetic mice

Objective of the Study

Diabetic patients have a much more widespread and aggressive form of atherosclerosis and therefore, higher risk for myocardial infarction, peripheral vascular disease and stroke, but the molecular mechanisms leading to accelerated damage are still unclear. Recently, we showed that hyperglycemia activates the transcription factor NFAT in the arterial wall, inducing the expression of the pro-atherosclerotic protein osteopontin. Here we investigate whether NFAT activation may be a link between diabetes and atherogenesis.

Methodology and Principal Findings

Streptozotocin (STZ)-induced diabetes in apolipoprotein E^−/− mice resulted in 2.2 fold increased aortic atherosclerosis and enhanced pro-inflammatory burden, as evidenced by elevated blood monocytes, endothelial activation- and inflammatory markers in aorta, and pro-inflammatory cytokines in plasma. In vivo treatment with the NFAT blocker A-285222 for 4 weeks completely inhibited the diabetes-induced aggravation of atherosclerosis, having no effect in non-diabetic mice. STZ-treated mice exhibited hyperglycemia and higher plasma cholesterol and triglycerides, but these were unaffected by A-285222. NFAT-dependent transcriptional activity was examined in aorta, spleen, thymus, brain, heart, liver and kidney, but only augmented in the aorta of diabetic mice. A-285222 completely blocked this diabetes-driven NFAT activation, but had no impact on the other organs or on splenocyte proliferation or cytokine secretion, ruling out systemic immunosuppression as the mechanism behind reduced atherosclerosis. Instead, NFAT inhibition effectively reduced IL-6, osteopontin, monocyte chemotactic protein 1, intercellular adhesion molecule 1, CD68 and tissue factor expression in the arterial wall and lowered plasma IL-6 in diabetic mice.

Conclusions

Targeting NFAT signaling may be a novel and attractive approach for the treatment of diabetic macrovascular complications.

NFATc3 regulates trypsinogen activation, neutrophil recruitment, and tissue damage in acute pancreatitis in mice

BACKGROUND & AIMS

The signaling mechanisms that regulate trypsinogen activation and inflammation in acute pancreatitis (AP) are unclear. We explored the involvement of the calcium- and calcineurin-dependent transcription factor nuclear factor of activated T cells (NFAT) in development of AP in mice.

METHODS

We measured levels of myeloperoxidase and macrophage inflammatory protein 2 (CXCL2), trypsinogen activation, and tissue damage in the pancreas 24 hours after induction of AP by retrograde infusion of taurocholate into the pancreatic ducts of wild-type, NFAT luciferase reporter (NFAT-luc), and NFATc3-deficient mice. We isolated acinar cells and measured NFAT nuclear accumulation, trypsin activity, and expression of NFAT-regulated genes.

RESULTS

Infusion of taurocholate increased the transcriptional activity of NFAT in the pancreas, aorta, lung, and spleen of NFAT-luc mice. Inhibition of NFAT with A-285222 blocked taurocholate-induced activation of NFAT in all organs. A-285222 also reduced taurocholate-induced increases in levels of amylase, myeloperoxidase, and CXCL2; activation of trypsinogen; necrosis of acinar cells; edema; leukocyte infiltration; and hemorrhage in the pancreas. NFATc3-deficient mice were protected from these effects of taurocholate. Similar results were obtained using an l-arginine-induced model of AP. Reverse-transcription polymerase chain reaction and confocal immunofluorescence analyses showed that NFATc3 is expressed by acinar cells. NFATc3 expression was activated by stimuli that increase intracellular calcium levels, and activation was prevented by the calcineurin blocker cyclosporin A or A-285222. Activation of trypsinogen by secretagogues in acinar cells was prevented by pharmacologic inhibition of NFAT signaling or lack of NFATc3. A-285222 also reduced expression of inflammatory cytokines such as CXCL2 in acinar cells.

CONCLUSIONS

NFATc3 regulates trypsinogen activation, inflammation, and pancreatic tissue damage during development of AP in mice and might be a therapeutic target.

Selective modulation of nuclear factor of activated T-cell function in restenosis by a potent bipartite peptide inhibitor

RATIONALE

Nuclear factor of activated T-cells (NFAT) is importantly implicated in pathological cardiac remodeling and vascular lesion formation. NFAT functionality is mainly regulated by calcineurin, a Ca(2+)-dependent multi-effector phosphatase. Calcineurin inhibitors such as cyclosporine A (CsA) were shown to be effective in the treatment of restenosis and vascular inflammation but with adverse side effects.

OBJECTIVE

This prompted the design of more selective inhibitors such as VIVIT and inhibitors of NFAT-calcineurin association, which unfortunately have a poor potency precluding clinical use.

METHODS AND RESULTS

Here, we describe the rational design of a potent bipartite inhibitor of NFAT-calcineurin interaction, MCV1, which targets two separate calcineurin docking motifs. Modeling, site-directed mutagenesis, and functional studies demonstrated that MCV1 acts by allosteric modulation of calcineurin. Comparable to CsA, MCV1 prevents NFAT activation at nanomolar potency without impairing calcineurin phosphatase activity, nuclear factor-κB nuclear import, and general cell signaling. In contrast, CsA but not MCV1-activated basal level extracellular signal-regulated kinases activity and prevented nuclear import of calcineurin, independent of NFAT activation. In vivo MCV1 abrogated NFAT-mediated T-cell activation in a model of PMA-elicited peritonitis, whereas topical application of MCV1 markedly reduced neointima formation in a mouse model of restenosis.

CONCLUSIONS

We designed a bipartite NFAT inhibitor that is more potent than VIVIT and more selective than CsA. MCV1 constitutes not only a powerful tool to unravel NFAT function but also a potential drug candidate for the treatment of diseases implicating NFAT activation.

Caveolin-1 deficiency decreases atherosclerosis by hampering leukocyte influx into the arterial wall and generating a regulatory T-cell response

Caveolin-1 plays a crucial role in atherosclerosis, which is mainly attributed to its effects on low-density-lipoprotein (LDL) transcytosis. However, caveolin-1 has also been implicated in the regulation of inflammation. We investigated the effects of caveolin-1 deficiency in atherosclerosis with its accompanying changes in plaque- and lymphoid-related immunology and inflammation. Cav1(-/-)Apoe(-/-) mice exhibited a 15-fold reduction in plaque size with plaques containing fewer macrophages, T cells, and neutrophils. Intravital microscopy revealed 83% less leukocyte adhesion to the vessel wall in Cav1(-/-)Apoe(-/-) mice, which could be attributed to reduced endothelial chemokine ligand-2 (CCL-2/MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) expression. Caveolin-1 deficiency resulted in a 57% increase in regulatory T cells and a 4% decrease in CD4(+) effector T cells in lymphoid organs. Bone marrow transplantations revealed that Cav1(-/-)Apoe(-/-) mice receiving Cav1(+/+)Apoe(-/-) or Cav1(-/-)Apoe(-/-) bone marrow presented 4- to 4.5-fold smaller plaques with no additional phenotypic changes. In contrast, atherosclerosis was not affected in Cav1(+/+) Apoe(-/-) recipients receiving Cav1(-/-)Apoe(-/-) or Cav1(+/+) Apoe(-/-) bone marrow. However, the presence of Cav1(-/-) Apoe(-/-) bone marrow was associated with an anti-inflammatory T-cell profile. Our study reveals that nonhematopoietic caveolin-1 determines plaque size, whereas hematopoietic caveolin-1 regulates lymphoid immune-modulation. However, both are required for phenotypic modulation of plaques.

Effects of immunomodulatory drugs on plasma inflammatory markers in a rabbit model of atherosclerosis

Atherosclerosis is a chronic disease of the arterial wall where both innate and adaptive immuno-inflammatory mechanisms are involved. Inflammatory cytokines are implicated in the development and progression of atherosclerotic lesions. Immunomodulatory therapies have been proposed for the treatment of atherosclerosis. Therefore, the aim of this study was to investigate the systemic anti-inflammatory and immunomodulatory effects of atorvastatin, cyclosporine A (CsA), and tacrolimus (FK506) on plasma inflammatory markers in atherosclerotic rabbits. Male New Zealand rabbits were randomized into five groups each of 12 animals. Standard diet-fed group served as control, and the cholesterol-fed group received a diet supplemented with 1% cholesterol alone, cholesterol + atorvastatin, cholesterol + FK506, and cholesterol + CsA. Serum levels of lipid profile parameters (triglycerides, cholesterol, and high-density lipoprotein) were measured using colorimetric methods. Serum levels of C-reactive protein (CRP), interleukin-6 (Il-6), and interferon-gamma (INF-γ) were measured in all studied groups using ELISA techniques. Our results revealed a significant decrease (p < 0.001) in the serum levels of lipid profile parameters, CRP, Il-6, and INF-γ in atorvastatin-treated group compared with the cholesterol-fed group. On the other hand, a non-significant difference was observed for the same parameters in either FK506- or CsA-treated groups compared with the cholesterol-fed group. In conclusion, atorvastatin has a systemic anti-inflammatory role that far surpassed the cholesterol reduction effect alone. FK506 or CsA failed to suppress elevated plasma inflammatory markers. Thus, low doses of these two immunomodulating drugs could not have generalized systemic anti-inflammatory or immunosuppressive effects.

Nuclear factor of activated T-cells transcription factors in the vasculature: the good guys or the bad guys?

PURPOSE OF REVIEW

The nuclear factor of activated T-cells (NFAT) proteins are a family of Ca/calcineurin-dependent transcription factors that were first characterized in T-lymphocytes as inducers of cytokine gene expression. Since then, NFAT proteins have been shown to play varied roles outside of the immune system, including in the cardiovascular system. Cells in the vessel wall display a diverse array of Ca signaling modalities, which are subject to change during disease. The fact that NFAT proteins are able to decode and translate these signals into changes in gene expression makes them potential regulators of vascular pathogenesis.

RECENT FINDINGS

It is now clear that NFAT signaling is required for normal vascular patterning during embryogenesis and for vascular endothelial growth factor-induced angiogenesis. The overall role of NFAT signaling in the vasculature, however, is less clear during adult life. This review aims to give an update on mechanisms that regulate NFAT activation in vascular cells, with an emphasis on the role of mitochondria and of upstream activators such as lipids and glucose. It also addresses recent work implicating NFAT proteins as mediators of vascular disease.

SUMMARY

A better understanding of the NFAT-signaling pathway in the vasculature may open up an unexplored area for the development of new therapeutic approaches for treating vascular disease.

Glycogen synthase kinase 3beta regulation of nuclear factor of activated T-cells isoform c1 in the vascular smooth muscle cell response to injury

The migration and proliferation of vascular smooth muscle cells (vSMCs) are critical events in neointima formation during atherosclerosis and restenosis. The transcription factor nuclear factor of activated T-cells-isoform c1 (NFATc1) is regulated by atherogenic cytokines, and has been implicated in the migratory and proliferative responses of vSMCs through the regulation of gene expression. In T-cells, calcineurin de-phosphorylates NFATc1, leading to its nuclear import, while glycogen synthase kinase 3 beta (GSK3beta) phosphorylates NFATc1 and promotes its nuclear export. However, the relationship between NFATc1 and GSK3beta has not been studied during SMC migration and proliferation. We investigated this by scrape wounding vSMCs in vitro, and studying wound repair. NFATc1 protein was transiently increased, reaching a peak at 8 h after wounding. Cell fractionation and immunocytochemistry revealed that NFATc1 accumulation in the nucleus was maximal at 4 h after injury, and this was coincident with a significant 9 fold increase in transcriptional activity. Silencing NFATc1 expression with siRNA or inhibition of NFAT with cyclosporin A (CsA) attenuated wound closure by vSMCs. Phospho-GSK3beta (inactive) increased to a peak at 30 min after injury, preceding the nuclear accumulation of NFATc1. Overexpression of a constitutively active mutant of GSK3beta delayed the nuclear accumulation of NFATc1, caused a 50% decrease in NFAT transcriptional activity, and attenuated vSMC wound repair. We conclude that NFATc1 promotes the vSMC response to injury, and that inhibition of GSK3beta is required for the activation of NFAT during wound repair.

The CD40-TRAF6 axis is the key regulator of the CD40/CD40L system in neointima formation and arterial remodeling

We investigated the role of CD40 and CD40L in neointima formation and identified the downstream CD40-signaling intermediates (tumor necrosis factor [TNF]-receptor associated factors [TRAF]) involved. Neointima formation was induced in wild-type, CD40(-/-), CD40L(-/-), and in CD40(-/-) mice that contained a CD40 transgene with or without mutations at the CD40-TRAF2,3&5, TRAF6, or TRAF2,3,5&6 binding sites. Compared with wild-type mice, CD40(-/-) mice showed a significant decrease in neointima formation with increased collagen deposition and decreased inflammatory cell infiltration. Neointima formation was also impaired in wild-type mice reconstituted with CD40(-/-) bone marrow. In vitro, the capacity of CD40(-/-) leukocytes to adhere to the endothelium was reduced. Ligated carotid arteries of CD40(-/-) mice showed a smaller total vessel volume and an impaired remodeling capacity, reflected by decreased gelatinolytic/collagenolytic activity. Comparable results were found in mice with defects in CD40-TRAF6 and CD40-TRAF 2/3/5&6 binding, but not in mice with defects in CD40-TRAF2/3&5 binding. Neointima formation and vascular remodeling in CD40-receptor-deficient mice is impaired, due to a decreased inflammatory cell infiltration and matrix-degrading protease activity, with CD40-TRAF6 signaling as the key regulator. This identifies the CD40-TRAF6 axis as a potential therapeutic target in vascular disease.

Therapeutic potential of VIVIT, a selective peptide inhibitor of nuclear factor of activated T cells, in cardiovascular disorders

Cardiovascular disease is the major cause of death in industrialized nations. Targeted intervention in calcineurin, a calmodulin-dependent, calcium-activated phosphatase and its substrate, nuclear factor of activated T cells (NFAT), was demonstrated to be effective in the treatment of cardiovascular diseases. Although effective in the disruption of calcineurin phosphatase activity, cyclosporin A (CsA) and FK506 also resulted in undesired side effects and toxicity, prompting the discovery of VIVIT, a novel peptide inhibitor. VIVIT selectively and potently inhibits calcineurin/NFAT interaction, but does not compromise calcineurin phosphatase activity and non-NFAT-mediated signaling. VIVIT displays a favorable therapeutic profile as a potential drug candidate and constitutes a useful tool in exploring calcineurin-NFAT functionality. This review describes the development of VIVIT peptide as a selective NFAT inhibitor and its application as a therapeutic agent in cardiovascular disorders including cardiac hypertrophy, restenosis, atherosclerosis, and angiogenesis.

Drug-induced immunomodulation to affect the development and progression of atherosclerosis: a new opportunity?

Inflammation and cytokine pathways are crucial for the development and progression of atherosclerotic lesions. In this review, the hypothesis that immunomodulatory drugs provide a possible therapeutic modality for cardiovascular disease is evaluated. Therefore, after a short overview of the specific inflammatory pathways involved in atherosclerosis, literature on the effect of several immunomodulatory drugs, such as nonsteroidal anti-inflammatory drugs, specific cyclooxygenase inhibitors and immunosuppressive drugs, used currently in the prevention of rejection after organ transplant, on the development and progression of atherosclerosis is reviewed. In addition, the pleiotropic immunomodulatory effect of two established cardiovascular drugs (angiotensin-converting enzyme inhibitors and statins) is discussed.

Selective Clearance of Macrophages in Atherosclerotic Plaques by Autophagy

OBJECTIVES

The purpose of this study was to investigate whether stent-based delivery of an inhibitor of mammalian target of rapamycin (mTOR) can selectively clear macrophages in rabbit atherosclerotic plaques.

BACKGROUND

Current pharmacologic approaches to stabilize atherosclerotic plaques have only partially reduced the incidence of acute coronary syndromes and sudden death. Macrophages play a pivotal role in plaque destabilization, whereas smooth muscle cells (SMC) promote plaque stability.

METHODS

Stents eluting the mTOR inhibitor everolimus were implanted in atherosclerotic arteries of cholesterol-fed rabbits. In addition, in vitro experiments using explanted atherosclerotic segments and cultured macrophages as well as SMC were performed.

RESULTS

Stents eluting everolimus led to a marked reduction in macrophage content without altering the amount of SMC compared with polymer control stents. In vitro studies showed that everolimus treatment induced inhibition of translation in both cultured macrophages and SMC. However, cell death occurred only in macrophages and was characterized by bulk degradation of long-lived proteins, processing of microtubule-associated protein light chain 3, and cytoplasmic vacuolization, which are all markers of autophagy. Everolimus-induced autophagy was mediated by mTOR inhibition, because cell viability was not affected using tacrolimus, an mTOR-independent everolimus analog. Moreover, mTOR gene silencing was associated with selective induction of macrophage cell death. Autophagic macrophage cell death was confirmed by transmission electron microscopy both in cultured cells and in atherosclerotic explants.

CONCLUSIONS

Stent-based delivery of everolimus selectively cleared macrophages in rabbit atherosclerotic plaques by autophagy, an mTOR inhibition-dependent and novel mechanism to induce cell death in mammalian cells.

FTY720, a Synthetic Sphingosine 1 Phosphate Analogue, Inhibits Development of Atherosclerosis in Low-Density Lipoprotein Receptor–Deficient Mice

BACKGROUND

Numerous in vitro studies suggest that sphingosine 1-phosphate (S1P), a bioactive lysosphingolipid associated with high-density lipoproteins, accounts at least partly for the potent antiinflammatory properties of high-density lipoprotein and, thereby, contributes to the antiatherogenic potential attributed to high-density lipoproteins. The present study was undertaken to investigate whether modulation of S1P signaling would affect atherosclerosis in a murine model of disease.

METHODS AND RESULTS

Low-density lipoprotein receptor-deficient mice on a cholesterol-rich diet were given FTY720, a synthetic S1P analogue, at low (0.04 mg/kg per day) or high (0.4 mg/kg per day) doses for 16 weeks. FTY720 dose-dependently reduced atherosclerotic lesion formation, both in the aortic root and brachiocephalic artery, and almost completely blunted necrotic core formation. Plasma lipids remained unchanged during the course of FTY720 treatment. However, FTY720 lowered blood lymphocyte count (at a high dose) and significantly interfered with lymphocyte function, as evidenced by reduced splenocyte proliferation and interferon-gamma levels in plasma. Plasma concentrations of proinflammatory cytokines such as tumor necrosis factor-alpha, interleukin (IL)-6, IL-12, and regulated on activation normal T cell expressed and secreted were reduced by FTY720 administration. Moreover, lipopolysaccharide-elicited generation of nitrite/nitrate and IL-6--two markers of classical (M1) macrophage activation--was inhibited, whereas IL-4-induced production of IL-1-receptor antagonist, a marker of alternative (M2) macrophage activation, was augmented in peritoneal macrophages from FTY720-treated low-density lipoprotein receptor-deficient mice.

CONCLUSIONS

The present results demonstrate that an S1P analogue inhibits atherosclerosis by modulating lymphocyte and macrophage function, and these results are consistent with the notion that S1P contributes to the antiatherogenic potential of high-density lipoprotein.

Preservation of Renal Function and Cardiovascular Risk Factors

An update is given about some factors leading to loss of renal allograft, especially in relation to the use of tacrolimus and cyclosporine. We discuss both immunological, such as suboptimal immunosuppression, acute rejection, and noncompliance, as well as nonimmunological factor's such as hypertension, hyperlipidemia, chronic toxic effects of immunosuppressants, older donors, and delayed graft function.

Apop-1, a novel protein inducing cyclophilin D-dependent but Bax/Bak-related channel-independent apoptosis

In the intrinsic pathway of apoptosis, mitochondria play a crucial role by releasing cytochrome c from the intermembrane space into the cytoplasm. Cytochrome c release through Bax/Bak-dependent channels in mitochondria has been well documented. In contrast, cyclophilin D (CypD), an important component of permeability transition pore-dependent protein release, remains largely undefined, and no apoptogenic proteins that act specifically in a CypD-dependent manner have been reported to date. Here, we describe a novel and evolutionarily conserved protein, apoptogenic protein (Apop). Mouse Apop-1 expression induces apoptotic death by releasing cytochrome c from mitochondria into the cytosolic space followed by activation of caspase-9 and -3. Apop-1-induced apoptosis is not blocked by Bcl-2 or Bcl-xL, inhibitors of Bax/Bak-dependent channels, whereas it is completely blocked by cyclosporin A, an inhibitor of permeability transition pore. Cells lacking CypD were resistant to Apop-induced apoptosis. Moreover, inhibition of Apop expression prevented the cell death induced by apoptosis-inducing substances. Our findings, thus, indicate that the expression of Apop-1 induces apoptosis though CypD-dependent pathway and that Apop-1 plays roles in cell death under physiological conditions.

Therapeutic Potential of a Synthetic Peptide Inhibitor of Nuclear Factor of Activated T Cells as Antirestenotic Agent

OBJECTIVE

The calcineurin/nuclear factor of activated T cells (NFAT) axis plays a pivotal role in the regulation of critical genes in vascular smooth muscle cell (vSMC) proliferation and inflammation, which makes NFAT inhibition an attractive modality in the prevention of restenosis.

METHODS AND RESULTS

Synthetic peptide VIVIT potently inhibited NFAT activation in RAW 264.7 macrophages, Ea.Hy.926 endothelial cells and vSMCs, and blocked ionomycin-elicited nuclear import of NFAT. VIVIT, as well as cyclosporine A (CsA) or FK506, completely blunted platelet-derived growth factor-BB (PDGF-BB) and thrombin-induced vSMC proliferation. Moreover, it significantly inhibited PDGF-BB and thrombin-induced interleukin-6, interleukin-8, transforming growth factor-beta1, stromal cell-derived factor-1alpha, and monocyte chemotactic protein-1 expression in vSMCs. Unlike FK506 or CsA, VIVIT did not affect nuclear factor kappaB reporter gene activation and did only marginally affect endothelial wound healing in vitro. VIVIT did not intervene in phorbol 12-myristate 13-acetate-stimulated extracellular signal-regulated kinase activation, confirming its specificity for NFAT. Furthermore, our data establish that NFAT is a regulator of PDGF-BB induced vSMC proliferation.

CONCLUSIONS

VIVIT appears to be a specific and potent inhibitor of NFAT activation and thus of NFAT-mediated proliferation and inflammation. Unlike FK506 or CsA, synthetic VIVIT therapy will not be accompanied by non-NFAT-mediated side effects on calcineurin signaling and constitutes a promising lead in antirestenotic therapy.