Cell-specific discrimination of desmosterol and desmosterol mimetics confers selective regulation of LXR and SREBP in macrophages.

Activation of liver X receptors (LXRs) with synthetic agonists promotes reverse cholesterol transport and protects against atherosclerosis in mouse models. Most synthetic LXR agonists also cause marked hypertriglyceridemia by inducing the expression of sterol regulatory element-binding protein (SREBP)1c and downstream genes that drive fatty acid biosynthesis. Recent studies demonstrated that desmosterol, an intermediate in the cholesterol biosynthetic pathway that suppresses SREBP processing by binding to SCAP, also binds and activates LXRs and is the most abundant LXR ligand in macrophage foam cells. Here we explore the potential of increasing endogenous desmosterol production or mimicking its activity as a means of inducing LXR activity while simultaneously suppressing SREBP1c-induced hypertriglyceridemia. Unexpectedly, while desmosterol strongly activated LXR target genes and suppressed SREBP pathways in mouse and human macrophages, it had almost no activity in mouse or human hepatocytes in vitro. We further demonstrate that sterol-based selective modulators of LXRs have biochemical and transcriptional properties predicted of desmosterol mimetics and selectively regulate LXR function in macrophages in vitro and in vivo. These studies thereby reveal cell-specific discrimination of endogenous and synthetic regulators of LXRs and SREBPs, providing a molecular basis for dissociation of LXR functions in macrophages from those in the liver that lead to hypertriglyceridemia

Null mutation for Macrophage Migration Inhibitory Factor (MIF) is associated with less aggressive bladder cancer in mice

<p>Abstract</p> <p>Background</p> <p>Inflammatory cytokines may promote tumorigenesis. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine with regulatory properties over tumor suppressor proteins involved in bladder cancer. We studied the development of bladder cancer in wild type (WT) and MIF knockout (KO) mice given N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN), a known carcinogen, to determine the role of MIF in bladder cancer initiation and progression.</p> <p>Methods</p> <p>5-month old male C57Bl/6 MIF WT and KO mice were treated with and without BBN. Animals were sacrificed at intervals up to 23 weeks of treatment. Bladder tumor stage and grade were evaluated by H&E. Immunohistochemical (IHC) analysis was performed for MIF and platelet/endothelial cell adhesion molecule 1 (PECAM-1), a measure of vascularization. MIF mRNA was analyzed by quantitative real-time polymerase chain reaction.</p> <p>Results</p> <p>Poorly differentiated carcinoma developed in all BBN treated mice by week 20. MIF WT animals developed T2 disease, while KO animals developed only T1 disease. MIF IHC revealed predominantly urothelial cytoplasmic staining in the WT control animals and a shift toward nuclear staining in WT BBN treated animals. MIF mRNA levels were 3-fold higher in BBN treated animals relative to controls when invasive cancer was present. PECAM-1 staining revealed significantly more stromal vessels in the tumors in WT animals when compared to KOs.</p> <p>Conclusion</p> <p>Muscle invasive bladder cancer with increased stromal vascularity was associated with increased MIF mRNA levels and nuclear redistribution. Consistently lower stage tumors were seen in MIF KO compared to WT mice. These data suggest that MIF may play a role in the progression to invasive bladder cancer.</p

Genome-Wide Association Study of Lp-PLA2 Activity and Mass in the Framingham Heart Study

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an emerging risk factor and therapeutic target for cardiovascular disease. The activity and mass of this enzyme are heritable traits, but major genetic determinants have not been explored in a systematic, genome-wide fashion. We carried out a genome-wide association study of Lp-PLA2 activity and mass in 6,668 Caucasian subjects from the population-based Framingham Heart Study. Clinical data and genotypes from the Affymetrix 550K SNP array were obtained from the open-access Framingham SHARe project. Each polymorphism that passed quality control was tested for associations with Lp-PLA2 activity and mass using linear mixed models implemented in the R statistical package, accounting for familial correlations, and controlling for age, sex, smoking, lipid-lowering-medication use, and cohort. For Lp-PLA2 activity, polymorphisms at four independent loci reached genome-wide significance, including the APOE/APOC1 region on chromosome 19 (p = 6×10−24); CELSR2/PSRC1 on chromosome 1 (p = 3×10−15); SCARB1 on chromosome 12 (p = 1×10−8) and ZNF259/BUD13 in the APOA5/APOA1 gene region on chromosome 11 (p = 4×10−8). All of these remained significant after accounting for associations with LDL cholesterol, HDL cholesterol, or triglycerides. For Lp-PLA2 mass, 12 SNPs achieved genome-wide significance, all clustering in a region on chromosome 6p12.3 near the PLA2G7 gene. Our analyses demonstrate that genetic polymorphisms may contribute to inter-individual variation in Lp-PLA2 activity and mass

Design and Rationale of the Global Phase 3 NEURO-TTRansform Study of Antisense Oligonucleotide AKCEA-TTR-LRx (ION-682884-CS3) in Hereditary Transthyretin-Mediated Amyloid Polyneuropathy

Introduction: AKCEA-TTR-LRx is a ligand-conjugated antisense (LICA) drug in development for the treatment of hereditary transthyretin amyloidosis (hATTR), a fatal disease caused by mutations in the transthyretin (TTR) gene. AKCEA-TTR-LRx shares the same nucleotide sequence as inotersen, an antisense medicine approved for use in hATTR polyneuropathy (hATTR-PN). Unlike inotersen, AKCEA-TTR-LRx is conjugated to a triantennary N-acetylgalactosamine moiety that supports receptor-mediated uptake by hepatocytes, the primary source of circulating TTR. This advanced design increases drug potency to allow for lower and less frequent dosing. The NEURO-TTRansform study will investigate whether AKCEA-TTR-LRx is safe and efficacious, with the aim of improving neurologic function and quality of life in hATTR-PN patients. Methods/design: Approximately 140 adults with stage 1 (independent ambulation) or 2 (requires ambulatory support) hATTR-PN are anticipated to enroll in this multicenter, open-label, randomized, phase 3 study. Patients will be assigned 6:1 to AKCEA-TTR-LRx 45 mg subcutaneously every 4 weeks or inotersen 300 mg once weekly until the prespecified week 35 interim efficacy analysis, after which patients receiving inotersen will receive AKCEA-TTR-LRx 45 mg subcutaneously every 4 weeks. All patients will then receive AKCEA-TTR-LRx through the remainder of the study treatment period. The final efficacy analysis at week 66 will compare the AKCEA-TTR-LRx arm with the historical placebo arm from the phase 3 trial of inotersen (NEURO-TTR). The primary outcome measures are between-group differences in the change from baseline in serum TTR, modified Neuropathy Impairment Score + 7, and Norfolk Quality of Life-Diabetic Neuropathy questionnaire. Conclusion: NEURO-TTRansform is designed to determine whether targeted delivery of AKCEA-TTR-LRx to hepatocytes with lower and less frequent doses will translate into clinical and quality-of-life benefits for patients with hATTR-PN

MIXED MODEL REPRESENTATION OF STATE SPACE MODELS: NEW SMOOTHING RESULTS AND THEIR APPLICATION TO REML ESTIMATION

Abstract: Known results for the general linear mixed model and its special case, the variance components model, are applied to inference in state space models. New state and disturbance smoothing algorithms that accomodate fixed effects and diffuse initial conditions are developed. The algorithms are based on an augmented Kalman filter, and they avoid the backward recursions of standard smoothing algorithms. The disturbance smoother is used to develop an EM algorithm for REML estimation of variance components in state space models. The EM algorithm for the structural time series model with polynomial trend and additive seasonality is illustrated in detail

Analysis of Multi-Unit Variance Components Models with State Space Profiles

Continuous-time stochastic models, EM algorithm, Kalman Filter, mixed model prediction, restricted maximum likelihood, smoothing splines, unequally spaced observations, variance components,

Likelihood-look-ahead inference on the equilibrium distribution of Markov chains

We propose a method for statistical inference on the stationary probability measure of a Markov chain with general state space whose transition function belongs to a parametric family. We extend the look-ahead method introduced by Glynn and Henderson to this situation, using maximum likelihood estimation based on data from the observed process. We show the consistency and asymptotic normality of our estimator and construct confidence intervals for the values of the stationary distribution. We illustrate our results with simulation studies of the Lindley process and the AR(1) process.Markov chain Maximum likelihood Look-ahead estimation Simulation Stationary distribution

Recursive hierarchic segmentation analysis of bone mineral density changes on digital panoramic images

Objective. The aim of this study was to demonstrate that histogram analysis and mathematical modeling of digital panoramic images (DPIs) processed using recursive hierarchic segmentation (RHSEG) discriminates normal, osteopenic, and osteoporotic cancellous bone.Study Design. Forty-seven DPIs of postmenopausal women were grouped into normal, osteopenic, and osteoporotic; dual-energy x-ray absorptiometry was the reference standard. RHSEG of the mandibular angle and canine/premolar trabecular regions of interest was performed. After histogram and histogram bin analysis and generation of relative intensity functions, generalized linear mixed model analysis was used to model the data and likelihood ratio testing used to assess group differences.Results. Histogram analyses discriminated among the groups. Receiver operating characteristic analysis of the canine/premolar data yielded area-under-the-curve accuracies of 0.78 for osteoporosis and 0.74 for osteopenia. Discrimination of osteoporosis required cubic analysis, discrimination of osteopenia required quartic analysis, and neither model alone discriminated among all groups.Conclusions. Analyses and mathematical modeling of mandibular trabecular bone on RHSEG-processed DPIs discriminated normal, osteoporotic, and osteopenic patients. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;113:549-558)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES