Viral Determinants of Integration Site Preferences of Simian Immunodeficiency Virus-Based Vectors

Preferential integration into transcriptionally active regions of genomes has been observed for retroviral vectors based on gamma-retroviruses and lentiviruses. However, differences in the integration site preferences were detected, which might be explained by differences in viral components of the preintegration complexes. Viral determinants of integration site preferences have not been defined. Therefore, integration sites of simian immunodeficiency virus (SIV)-based vectors produced in the absence of accessory genes or lacking promoter and enhancer elements were compared. Similar integration patterns for the different SIV vectors indicate that vif, vpr, vpx, nef, env, and promoter or enhancer elements are not required for preferential integration of SIV into transcriptionally active regions of genomes

Nuclear localization of tetrahydrobiopterin biosynthetic enzymes

Biosynthesis of the tetrahydrobiopterin (BH4) cofactor, essential for catecholamines and serotonin production and nitric oxide synthase (NOS) activity, requires the enzymes GTP cyclohydrolase I (GTPCH), 6-pyruvoyl-tetrahydropterin synthase (PTPS), and sepiapterin reductase (SR). Upon studying the distribution of GTPCH and PTPS with polyclonal immune sera in cross sections of rat brain, prominent nuclear staining in many neurons was observed besides strong staining in peri-ventricular structures. Furthermore, localization studies in transgenic mice expressing a Pts-LacZ gene fusion containing the N-terminal 35 amino acids of PTPS revealed β-galactosidase in the nucleus of neurons. In contrast, PTPS-β-galactosidase was exclusively cytoplasmic in the convoluted kidney tubules but nuclear in other parts of the nephron, indicating again that nuclear targeting may occur only in specific cell categories. Furthermore, the N terminus of PTPS acts as a domain able to target the PTPS-β-galactosidase fusion protein to the nucleus. In transiently transfected COS-1 cells, which do not express GTPCH and PTPS endogenously, we found cytoplasmic and nuclear staining for GTPCH and PTPS. To further investigate nuclear localization of all three BH4- biosynthetic enzymes, we expressed Flag-fusion proteins in transiently transfected COS-1 cells and analyzed the distribution by immunolocalization and sub-cellular fractionation using anti-Flag antibodies and enzymatic assays. Whereas 5-10% of total GTPCH and PTPS and ∼1% of total SR were present in the nucleus, only GTPCH was confirmed to be an active enzyme in nuclear fractions. The in vitro studies together with the tissue staining corroborate specific nuclear localization of BH4-biosynthetic proteins with yet unknown biological function. © 2003 Elsevier B.V. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Inhibition of TRIF-Dependent Inflammation Decelerates Afterload-Induced Myocardial Remodeling

Pressure-overload-induced cardiac hypertrophy represents one cause of the development of heart failure. The aim of this study is to characterize the influence of the TIR-domain-containing adapter-inducing interferon-β (TRIF) during afterload-induced myocardial remodeling. After transaortic constriction (TAC), cardiac pressure overload leads to an early increase in MyD88- (Myeloid differentiation primary response gene 88) and TRIF-dependent cytokines. The maximum cytokine expression appeared within the first week and decreased to its control level within five weeks. While cardiomyocyte hypertrophy was comparable, the myocardial accumulation of the inflammatory cells was lower in TRIF−/−mice. At d7, TRIF deficiency reduced transcription factors and TRIF-dependent cytokines. Through the modulation of the TGF-β-signaling pathway and anti-fibrotic microRNAs, TRIF was involved in the development of interstitial fibrosis. The absence of TRIF was associated with a decreased expression of proapoptotic proteins. In echocardiography and working heart analyses, TRIF deficiency slowed left-ventricular wall thickening, myocardial hypertrophy, and reduces the ejection fraction. In summary, TRIF is an important adapter protein for the release of inflammatory cytokines and the accumulation of inflammatory cells in the early stage of maladaptive cardiac remodeling. TRIF is involved in the development of cardiac fibrosis by modulating inflammatory and fibrotic signal transduction pathways

Efficacy and Safety of Bempedoic Acid in Patients With Hypercholesterolemia and Statin Intolerance

Background Inability to tolerate statins because of muscle symptoms contributes to uncontrolled cholesterol levels and insufficient cardiovascular risk reduction. Bempedoic acid, a prodrug that is activated by a hepatic enzyme not present in skeletal muscle, inhibits ATP -citrate lyase, an enzyme upstream of β-hydroxy β-methylglutaryl-coenzyme A reductase in the cholesterol biosynthesis pathway. Methods and Results The phase 3, double-blind, placebo-controlled CLEAR (Cholesterol Lowering via Bempedoic acid, an ACL-Inhibiting Regimen) Serenity study randomized 345 patients with hypercholesterolemia and a history of intolerance to at least 2 statins (1 at the lowest available dose) 2:1 to bempedoic acid 180 mg or placebo once daily for 24 weeks. The primary end point was mean percent change from baseline to week 12 in low-density lipoprotein cholesterol. The mean age was 65.2 years, mean baseline low-density lipoprotein cholesterol was 157.6 mg/dL, and 93% of patients reported a history of statin-associated muscle symptoms. Bempedoic acid treatment significantly reduced low-density lipoprotein cholesterol from baseline to week 12 (placebo-corrected difference, -21.4% [95% CI, -25.1% to -17.7%]; P<0.001). Significant reductions with bempedoic acid versus placebo were also observed in non-high-density lipoprotein cholesterol (-17.9%), total cholesterol (-14.8%), apolipoprotein B (-15.0%), and high-sensitivity C-reactive protein (-24.3%; P<0.001 for all comparisons). Bempedoic acid was safe and well tolerated. The most common muscle-related adverse event, myalgia, occurred in 4.7% and 7.2% of patients who received bempedoic acid or placebo, respectively. Conclusions Bempedoic acid offers a safe and effective oral therapeutic option for lipid lowering in patients who cannot tolerate statins. Clinical Trial Registration URL : https://www.clinicaltrials.gov . Unique identifier: NCT 02988115