Reversal of disease-related pathologies in the fragile X mouse model by selective activation of GABAB receptors with arbaclofen.

Fragile X syndrome (FXS), the most common inherited cause of intellectual disability and autism, results from the transcriptional silencing of FMR1 and loss of the mRNA translational repressor protein fragile X mental retardation protein (FMRP). Patients with FXS exhibit changes in neuronal dendritic spine morphology, a pathology associated with altered synaptic function. Studies in the mouse model of fragile X have shown that loss of FMRP causes excessive synaptic protein synthesis, which results in synaptic dysfunction and altered spine morphology. We tested whether the pharmacologic activation of the γ-aminobutyric acid type B (GABA(B)) receptor could correct or reverse these phenotypes in Fmr1-knockout mice. Basal protein synthesis, which is elevated in the hippocampus of Fmr1-knockout mice, was corrected by the in vitro application of the selective GABA(B) receptor agonist STX209 (arbaclofen, R-baclofen). STX209 also reduced to wild-type values the elevated AMPA receptor internalization in Fmr1-knockout cultured neurons, a known functional consequence of increased protein synthesis. Acute administration of STX209 in vivo, at doses that modify behavior, decreased mRNA translation in the cortex of Fmr1-knockout mice. Finally, the chronic administration of STX209 in juvenile mice corrected the increased spine density in Fmr1-knockout mice without affecting spine density in wild-type mice. Thus, activation of the GABA(B) receptor with STX209 corrected synaptic abnormalities considered central to fragile X pathophysiology, a finding that suggests that STX209 may be a potentially effective therapy to treat the core symptoms of FXS.

Identificação de genes envolvidos na síntese de proteínas de células musculares lisas com expressão aumentada em placas ateromatosas associados a hiperplasia neointimal após implante de stents não-farmacológicos: estudo GENESIS-R / Identification of genes involved in smooth muscle cell protein synthesis with increased expression in atheromathous plaques associated to neointim al hyperplasia after bare-metal stenting: GENESISI-R Study

Introdução: A reestenose coronária é um fenômeno pouco compreendidoe que permanece como um desafio mesmo na era dos stents farmacológicos. Este estudo tem como objetivo identificar genes envolvidos na síntese de proteínas estruturais e funcionais de células musculares lisas com expressão aumentada em placas ateromatosas de humanos associadosa hiperplasia neointimal após o implante de stents não-farmacológicos. Métodos: Placas ateromatosas foram obtidasmediante aterectomia direcionada, previamente ao implante do stent. A análise da expressão dos genes foi realizada utilizando-se o sistema Affymetrix GeneChip. Os pacientes foramsubmetidos a ultrassom intracoronário 6 meses após o procedimento para análise volumétrica intrastent. Foi avaliada a correlação entre a expressão gênica de placas ateromatosas e o porcentual de hiperplasia intimal intrastent. Resultados: A maioria dos pacientes era do sexo masculino (85,7%), com60,2 ± 11,4 anos de idade, 35,7% eram diabéticos e o porcentual de hiperplasia intimal intrastent foi de 29,9 ± 18,7%.Não houve variação do porcentual de hiperplasia intimal intrastent entre os pacientes com ou sem diabetes (29,5% vs. 30,7%; P = 0,89). Não houve correlação entre a extensão do stent e o porcentual de hiperplasia intimal intrastent (r = -0,26; P = 0,26) ou entre o diâmetro do stent e o porcentual dehiperplasia intimal intrastent (r = 0,14; P = 0,56). Oito genes envolvidos na síntese de proteínas estruturais e funcionais de células musculares lisas apresentaram correlação positiva como porcentual de hiperplasia intimal intrastent. Conclusões: As lesões coronárias de novo apresentam expressão aumentada de genes relacionados com a síntese de proteínas estruturais e funcionais de células musculares lisas associados a futurahiperplasia neointimal intrastent significativa, surgindo como novos alvos terapêuticos.

Myeloid-related protein 8/14 and the risk of cardiovascular death or myocardial infarction after an acute coronary syndrome in the Pravastatin or Atorvastatin Evaluation and Infection Therapy: Thrombolysis in Myocardial Infarction (PROVE IT-TIMI 22) trial.

BACKGROUND: Using a transcriptional profiling approach, we recently identified myeloid-related protein 8/14 (MRP-8/14) to be expressed by platelets during acute myocardial infarction (MI). Elevated concentrations of MRP-8/14 are associated with a higher risk for future cardiovascular events in apparently healthy individuals but have not been assessed with respect to prognosis in patients with acute coronary syndrome. METHODS: We performed a nested case-control study (n = 237 case-control pairs) among patients enrolled in the Pravastatin or Atorvastatin Evaluation and Infection Therapy: Thrombolysis in Myocardial Infarction 22 (PROVE IT-TIMI 22) trial (mean follow-up 24 months) to investigate the risk of cardiovascular death or MI associated with MRP-8/14 measured at 30 days after an acute coronary syndrome. RESULTS: Patients with cardiovascular death or MI after 30 days (cases) had higher median [25th, 75th percentile] MRP-8/14 levels than patients who remained free of recurrent events (5.6 [2.8, 13.5] mg/L vs 4.0 [1.9, 10.1] mg/L, P = .020). The risk of a recurrent cardiovascular event increased with each increasing quartile of MRP-8/14 (P-trend = 0.007) such that patients with the highest levels had a 2.0-fold increased odds (95% CI 1.1-3.6, P = .029) of a recurrent event after adjusting for standard risk indicators, randomized treatment, and C-reactive protein. Patients with elevated levels of MRP-8/14 and high-sensitivity C-reactive protein showed significantly increased risk of cardiovascular death or MI compared with patients with the lowest levels of both markers (adjusted odds ratio 2.1, 95% CI 1.2-3.8). CONCLUSIONS: Myeloid-related protein 8/14 may be a useful biomarker of platelet and inflammatory disease activity in atherothrombosis and may serve as a novel target for therapeutic intervention.

Quantitation of peripheral blood markers of rat experimental autoimmune encephalomyelitis.

Identification and quantitation of peripheral blood non-invasive, cell-surface markers of EAE disease activity and drug response would facilitate the preclinical development of potential therapeutics. Towards this end, we characterized the influx of immune mediators into spinal cords of diseased rats to establish the kinetics of T cell and monocyte-mediated inflammation. We then examined the periphery for regulation of T cell and monocyte activation. We report increased CD80 and VLA-4 expression on peripheral blood monocytes (PBM) during the onset and peak of experimental disease scores. Increased CD4+, CD62L - and CD4+, CD134+ T cells were detected only at disease peak, not during disease onset. PBM CD80 expression was significantly inhibited in CSA-treated animals, but increased in Dex-treated animals. PBM VLA-4 expression was unaffected by drug treatment. Both CSA and Dex inhibited CD62L shedding and CD134 expression on peripheral CD4+ T cells. These results identify quantitative, peripheral markers of disease activity and drug response.

Use of molecular imaging to quantify response to IKK-2 inhibitor treatment in murine arthritis.

OBJECTIVE: The NF-kappaB signaling pathway promotes the immune response in rheumatoid arthritis (RA) and in rodent models of RA. NF-kappaB activity is regulated by the IKK-2 kinase during inflammatory responses. To elucidate how IKK-2 inhibition suppresses disease development, we used a combination of in vivo imaging, transcription profiling, and histopathology technologies to study mice with antibody-induced arthritis. METHODS: ML120B, a potent, small molecule inhibitor of IKK-2, was administered to arthritic animals, and disease activity was monitored. NF-kappaB activity in diseased joints was quantified by in vivo imaging. Quantitative reverse transcriptase-polymerase chain reaction was used to evaluate gene expression in joints. Protease-activated near-infrared fluorescence (NIRF) in vivo imaging was applied to assess the amounts of active proteases in the joints. RESULTS: Oral administration of ML120B suppressed both clinical and histopathologic manifestations of disease. In vivo imaging demonstrated that NF-kappaB activity in inflamed arthritic paws was inhibited by ML120B, resulting in significant suppression of multiple genes in the NF-kappaB pathway, i.e., KC, epithelial neutrophil-activating peptide 78, JE, intercellular adhesion molecule 1, CD3, CD68, tumor necrosis factor alpha, interleukin-1beta, interleukin-6, inducible nitric oxide synthase, cyclooxygenase 2, matrix metalloproteinase 3, cathepsin B, and cathepsin K. NIRF in vivo imaging demonstrated that ML120B treatment dramatically reduced the amount of active proteases in the joints. CONCLUSION: Our data demonstrate that IKK-2 inhibition in the murine model of antibody-induced arthritis suppresses both inflammation and joint destruction. In addition, this study highlights how gene expression profiling can facilitate the identification of surrogate biomarkers of disease activity and treatment response in an experimental model of arthritis.

PKC-theta-deficient mice are protected from Th1-dependent antigen-induced arthritis.

T cell effector functions contribute to the pathogenesis of rheumatoid arthritis. PKC-theta transduces the signal from the TCR through activation of transcription factors NF-kappaB, AP-1, and NFAT. We examined the effects of PKC-theta deficiency on two Th1-dependent models of Ag-induced arthritis and found that PKC-theta-deficient mice develop disease, but at a significantly diminished severity compared with wild-type mice. In the methylated BSA model, cellular infiltrates and articular cartilage damage were mild in the PKC-theta-deficient mice as compared with wild-type mice. Quantitation of histopathology reveals 63 and 77% reduction in overall joint destruction in two independent experiments. In the type II collagen-induced arthritis model, we observed a significant reduction in clinical scores (p < 0.01) in three independent experiments and diminished joint pathology (p < 0.005) in PKC-theta-deficient compared with wild-type littermates. Microcomputerized tomographic imaging revealed that PKC-theta deficiency also protects from bone destruction. PKC-theta-deficient CD4(+) T cells show an impaired proliferative response, decreased intracellular levels of the cytokines IFN-gamma, IL-2, and IL-4, and significantly diminished cell surface expression of the activation markers CD25, CD69, and CD134/OX40 on memory T cells. We demonstrate decreased T-bet expression and significantly reduced IgG1 and IgG2a anti-collagen II Ab levels in PKC-theta-deficient mice. Collectively, our results demonstrate that PKC-theta deficiency results in an attenuated response to Ag-induced arthritis, which is likely mediated by the reduced T cell proliferation, Th1/Th2 cell differentiation and T cell activation before and during disease peak.

Platelet expression profiling and clinical validation of myeloid-related protein-14 as a novel determinant of cardiovascular events.

BACKGROUND: Platelets participate in events that immediately precede acute myocardial infarction. Because platelets lack nuclear DNA but retain megakaryocyte-derived mRNAs, the platelet transcriptome provides a novel window on gene expression preceding acute coronary events. METHODS AND RESULTS: We profiled platelet mRNA from patients with acute ST-segment-elevation myocardial infarction (STEMI, n=16) or stable coronary artery disease (n=44). The platelet transcriptomes were analyzed and single-gene models constructed to identify candidate genes with differential expression. We validated 1 candidate gene product by performing a prospective, nested case-control study (n=255 case-control pairs) among apparently healthy women to assess the risk of future cardiovascular events (nonfatal myocardial infarction, nonfatal stroke, and cardiovascular death) associated with baseline plasma levels of the candidate protein. Platelets isolated from STEMI and coronary artery disease patients contained 54 differentially expressed transcripts. The strongest discriminators of STEMI in the microarrays were CD69 (odds ratio 6.2, P<0.001) and myeloid-related protein-14 (MRP-14; odds ratio 3.3, P=0.002). Plasma levels of MRP-8/14 heterodimer were higher in STEMI patients (17.0 versus 8.0 microg/mL, P<0.001). In the validation study, the risk of a first cardiovascular event increased with each increasing quartile of MRP-8/14 (Ptrend<0.001) such that women with the highest levels had a 3.8-fold increase in risk of any vascular event (P<0.001). Risks were independent of standard risk factors and C-reactive protein. CONCLUSIONS: The platelet transcriptome reveals quantitative differences between acute and stable coronary artery disease. MRP-14 expression increases before STEMI, and increasing plasma concentrations of MRP-8/14 among healthy individuals predict the risk of future cardiovascular events.