Impact of a Medication Optimization Clinic on Heart Failure Hospitalizations

Efforts to optimize guideline-directed medical therapy (GDMT) through team-based care may affect outcomes in patients with heart failure with reduced ejection fraction (HFrEF). This study evaluated the impact of an innovative medication optimization clinic (MOC) on GDMT and outcomes in patients with HFrEF. Patients with HFrEF who are not receiving optimal GDMT are referred to MOC and managed by a team comprised of a nurse practitioner or physician assistant, clinical pharmacist, and HF cardiologist. We retrospectively evaluated the impact of MOC (n = 206) compared with usual care (n = 412) with a 2:1 propensity-matched control group. The primary clinical outcome was the incidence of HF hospitalizations at 3 months after the index visit. Kaplan-Meier cumulative event curves and Cox proportional hazards regression models with adjustment were conducted. A significantly higher proportion of patients in MOC received quadruple therapy (49% vs 4%, p <0.0001), angiotensin receptor neprilysin inhibitor (60% vs 27%, p <0.0001), mineralocorticoid receptor antagonist (59% vs 37%, p <0.0001), and sodium-glucose cotransporter-2 inhibitor (60% vs 10%, p <0.0001). The primary outcome was significantly lower in the MOC versus the control group (log-rank, p = 0.0008). Cox regression showed that patients in the control group were more than threefold more likely to be hospitalized because of HF than those in the MOC group (p = 0.0014). In conclusion, the MOC was associated with improved GDMT and lower risk of HF hospitalizations in patients with HFrEF.

Epigenetic regulation in Drosophila

Epigenetic regulation of gene transcription relies on molecular marks like DNA methylation or histone modifications. Here we review recent advances in our understanding of epigenetic regulation in the fruit fly Drosophila melanogaster. In the past, DNA methylation research has primarily utilized mammalian model systems. However, several recent landmark discoveries have been made in other organisms. For example, the interaction between DNA methylation and histone methylation was first described in the filamentous fungus Neurospora crassa. Another example is provided by the interaction between epigenetic modifications and the RNA interference (RNAi) machinery that was first reported in the fission yeast Schizosaccharomyces pombe. Another organism with great experimental power is the fruit fly Drosophila. Epigenetic regulation by chromatin has been extensively analyzed in the fly and several of the key components have been discovered in this organism. In this chapter, we will focus on three aspects that represent the complexity of epigenetic gene regulation. (1) We will discuss the available data about the DNA methylation system, (2) we will illuminate the interaction between DNA methylation and chromatin regulation, and (3) we will provide an overview over the Polycomb system of epigenetic chromatin modifiers that has proved to be an important paradigm for a chromatin system regulating epigenetic programming.

Mechanism of regulation of hsp70 chaperones by DnaJ cochaperones

Hsp70 chaperones assist a large variety of protein folding processes within the entire lifespan of proteins. Central to these activities is the regulation of Hsp70 by DnaJ cochaperones. DnaJ stimulates Hsp70 to hydrolyze ATP, a key step that closes its substrate-binding cavity and thus allows stable binding of substrate. We show that DnaJ stimulates ATP hydrolysis by Escherichia coli Hsp70, DnaK, very efficiently to >1000-fold, but only if present at high (micromolar) concentration. In contrast, the chaperone activity of DnaK in luciferase refolding was maximal at several hundredfold lower concentration of DnaJ. However, DnaJ was capable of maximally stimulating the DnaK ATPase even at this low concentration, provided that protein substrate was present, indicating synergistic action of DnaJ and substrate. Peptide substrates were poorly effective in this synergistic action. DnaJ action required binding of protein substrates to the central hydrophobic pocket of the substrate-binding cavity of DnaK, as evidenced by the reduced ability of DnaJ to stimulate ATP hydrolysis by a DnaK mutant with defects in substrate binding. At high concentrations, DnaJ itself served as substrate for DnaK in a process considered to be unphysiological. Mutant analysis furthermore revealed that DnaJ-mediated stimulation of ATP hydrolysis requires communication between the ATPase and substrate-binding domains of DnaK. This mechanism thus allows DnaJ to tightly couple ATP hydrolysis by DnaK with substrate binding and to avoid jamming of the DnaK chaperone with peptides. It probably is conserved among Hsp70 family members and is proposed to account for their functional diversity.

Interaction between the human nuclear cap-binding protein complex and hnRNP F

hnRNP F was identified in a screen for proteins that interact with human CBP80 and CBP20, the components of the nuclear cap-binding complex (CBC). In vitro interaction studies showed that hnRNP F can bind to both CBP20 and CBP80 individually. hnRNP F and CBC bind independently to RNA, but hnRNP F binds preferentially to CBC-RNA complexes rather than to naked RNA. The hnRNP H protein, which is 78% identical to hnRNP F and also interacts with both CBP80 and CBP20 in vitro, does not discriminate between naked RNA and CBC-RNA complexes, showing that this effect is specific. Depletion of hnRNP F from HeLa cell nuclear extract decreases the efficiency of pre-mRNA splicing, a defect which can be partially compensated by addition of recombinant hnRNP F. Thus, hnRNP F is required for efficient pre-mRNA splicing in vitro and may participate in the effect of CBC on pre-mRNA splicing.

A role for the M9 transport signal of hnRNP A1 in mRNA nuclear export

Among the nuclear proteins associated with mRNAs before their export to the cytoplasm are the abundant heterogeneous nuclear (hn) RNPs. Several of these contain the M9 signal that, in the case of hnRNP A1, has been shown to be sufficient to signal both nuclear export and nuclear import in cultured somatic cells. Kinetic competition experiments are used here to demonstrate that M9-directed nuclear import in Xenopus oocytes is a saturable process. Saturating levels of M9 have, however, no effect on the import of either U snRNPs or proteins carrying a classical basic NLS. Previous work demonstrated the existence of nuclear export factors specific for particular classes of RNA. Injection of hnRNP A1 but not of a mutant protein lacking the M9 domain inhibited export of mRNA but not of other classes of RNA. This suggests that hnRNP A1 or other proteins containing an M9 domain play a role in mRNA export from the nucleus. However, the requirement for M9 function in mRNA export is not identical to that in hnRNP A1 protein transport.

Adenovirus-assisted lipofection: efficient in vitro gene transfer of luciferase and cytosine deaminase to human smooth muscle cells

Smooth muscle cells (SMC) are a central cell type involved in multiple processes of coronary artery diseases including restenosis and therefore are major target cells for different aspects of gene transfer. Previous attempts to transfect primary arterial cells using different techniques like liposomes, CaPO4 and electroporation resulted in only low transfection efficiency. The development of recombinant adenoviruses dramatically improved the delivery of foreign genes into different cell types including SMC. However, cloning and identification of recombinants remain difficult and time-consuming techniques. The present study demonstrates that a complex consisting of reporter plasmid encoding firefly luciferase (pLUC), polycationic liposomes and replication-deficient adenovirus was able to yield very high in vitro transfection of primary human smooth muscle cells under optimized conditions. The technique of adenovirus-assisted lipofection (AAL) increases transfer and expression of plasmid DNA in human smooth muscle cells in vitro up to 1000-fold compared to lipofection. To verify the applicability of AAL for gene transfer into human smooth muscle cells we studied a gene therapy approach to suppress proliferation of SMC in vitro, using the prokaryotic cytosine deaminase gene (CD) which enables transfected mammalian cells to deaminate 5-fluorocytosine (5-FC) to the highly toxic 5-fluorouracil (5-FU). The effect of a transient CD expression on RNA synthesis was investigated by means of a cotransfection with a RSV-CD expression plasmid and the luciferase reporter plasmid. Western blot analysis demonstrated high expression of CD protein in transfected SMC. Cotransfected SMC demonstrated two-fold less luciferase activity in the presence of 5-FC (5 mmol/l) after 48 h compared to cells transfected with a non-CD coding plasmid. The data demonstrate that a transient expression of CD could be sufficient to reduce the capacity of protein synthesis in human SMC. This simple and effective in vitro transfection method may also be applicable to in vivo delivery of target genes to the vascular wall to inhibit SMC proliferation.

The biology and chemistry of Epstein-Barr virus

Epstein-Barr virus (EBV) is the human prototype of a family of closely related herpesviruses of Old World primates. These agents probably evolved and spread among the Old World primates since the divergence of apes from monkeys about 30 million years ago. Although the DNAs of the EBV family have no sequence homology to other herpesviruses, there are some features in common with other herpesviral genomes. EBV DNA is unusual in having five tandem direct repeat elements which divide the genome into five unique sequence domains. The tandem direct repeats at the ends of the linear virion DNA probably mediate circularization of the viral DNA to form the circular episomal viral DNA which is characteristic of EBV-infected cells. In latent transforming infection, messenger RNAs are encoded by three widely separate regions of the EBV genome. The remainder of the viral genome encodes many RNAs and proteins which are expressed in productive infection. Early and late viral genes are intermixed along the full length of EBV DNA.

Epstein-Barr virus (B95-8) DNA VII: molecular cloning and detailed mapping

Two of the Sal I fragments and all of the internal BamHI fragments (with the exception of BamHI c, a 0.6 x 10(6) dalton fragment) of Epstein-Barr virus (EBV) DNA have been cloned in pBR322. The termini and other parts of the DNA (including the EcoRI fragment which contains BamHI c) have been cloned as EcoRI fragments in bacteriophage Charon 4A. The cloned DNAs have been used to derive a complete map of the BamHI fragments of EBV DNA and to align the BamHI, EcoRI, HindIII, and SalI cleavage sites in EBV DNA.