TOMM40 regulates hepatocellular and plasma lipid metabolism via an LXR-dependent pathway.

Objective: The gene encoding TOMM40 (Transporter of Outer Mitochondrial Membrane 40) is adjacent to that encoding APOE, which has a central role in lipid and lipoprotein metabolism. While human genetic variants near APOE and TOMM40 have been shown to be strongly associated with plasma lipid levels, a specific role for TOMM40 in lipid metabolism has not been established, and the present study was aimed at assessing this possibility.

Methods: TOMM40 was knocked down by siRNA in human hepatoma HepG2 cells, and effects on mitochondrial function, lipid phenotypes, and crosstalk between mitochondria, ER, and lipid droplets were examined.

The Silent Threat: Bartonella quintana Endocarditis Unveiling Heart Failure and Severe Pulmonary Hypertension.

BACKGROUND Bartonella quintana is a slow-growing gram-negative bacterium that can cause severe culture-negative endocarditis. In many cases, its insidious onset can be difficult to diagnose given the variable symptoms in the early phases of the disease. This delay in detection and thus treatment can cause advanced consequences of the disease, including heart failure and severe pulmonary hypertension.

Deep Learning Algorithms to Detect Murmurs Associated With Structural Heart Disease.

Background The success of cardiac auscultation varies widely among medical professionals, which can lead to missed treatments for structural heart disease. Applying machine learning to cardiac auscultation could address this problem, but despite recent interest, few algorithms have been brought to clinical practice. We evaluated a novel suite of Food and Drug Administration-cleared algorithms trained via deep learning on >15 000 heart sound recordings.

Rapid Multiplexed Flow Cytometric Validation of CRISPRi sgRNAs in Tissue Culture.

Genome-wide CRISPR-based screening is a powerful tool in forward genetics, enabling biologic discovery by linking a desired phenotype to a specific genetic perturbation. However, hits from a genome-wide screen require individual validation to reproduce and accurately quantify their effects outside of a pooled experiment. Here, we describe a step-by-step protocol to rapidly assess the effects of individual sgRNAs from CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) systems.

Heparin Does Not Regulate Circulating Human PCSK9 (Proprotein Convertase Subtilisin-Kexin Type 9) in a General Population-Brief Report.

Background: PCSK9 (proprotein convertase subtilisin-kexin type 9) chaperones the hepatic LDLR (low-density lipoprotein receptor) for lysosomal degradation, elevating serum LDL (low-density lipoprotein) cholesterol and promoting atherosclerotic heart disease. Though the major effect on the hepatic LDLR comes from secreted PCSK9, the details of PCSK9 reuptake into the hepatocyte remain unclear. In both tissue culture and animal models, HSPGs (heparan sulfate proteoglycans) on hepatocytes act as co-receptors to promote PCSK9 reuptake.

Deep Learning Algorithm for Automated Cardiac Murmur Detection via a Digital Stethoscope Platform.

Background Clinicians vary markedly in their ability to detect murmurs during cardiac auscultation and identify the underlying pathological features. Deep learning approaches have shown promise in medicine by transforming collected data into clinically significant information. The objective of this research is to assess the performance of a deep learning algorithm to detect murmurs and clinically significant valvular heart disease using recordings from a commercial digital stethoscope platform.

A SARS-CoV-2-Human Protein-Protein Interaction Map Reveals Drug Targets and Potential Drug-Repurposing.

An outbreak of the novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 290,000 people since the end of 2019, killed over 12,000, and caused worldwide social and economic disruption. There are currently no antiviral drugs with proven efficacy nor are there vaccines for its prevention. Unfortunately, the scientific community has little knowledge of the molecular details of SARS-CoV-2 infection.

A SARS-CoV-2 protein interaction map reveals targets for drug repurposing.

A newly described coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of coronavirus disease 2019 (COVID-19), has infected over 2.3 million people, led to the death of more than 160,000 individuals and caused worldwide social and economic disruption. There are no antiviral drugs with proven clinical efficacy for the treatment of COVID-19, nor are there any vaccines that prevent infection with SARS-CoV-2, and efforts to develop drugs and vaccines are hampered by the limited knowledge of the molecular details of how SARS-CoV-2 infects cells.

Cell-associated heparin-like molecules modulate the ability of LDL to regulate PCSK9 uptake.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) targets the LDL receptor (LDLR) for degradation, increasing plasma LDL and, consequently, cardiovascular risk. Uptake of secreted PCSK9 is required for its effect on the LDLR, and LDL itself inhibits this uptake, though how it does so remains unclear. In this study, we investigated the relationship between LDL, the PCSK9:LDLR interaction, and PCSK9 uptake.

A High-Throughput Luciferase Assay to Evaluate Proteolysis of the Single-Turnover Protease PCSK9.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a single-turnover protease which regulates serum low-density lipoprotein (LDL) levels and, consequently, cardiovascular disease. Although PCSK9 proteolysis is required for its full hypercholesterolemic effect, the evaluation of its proteolytic function is challenging: PCSK9 is only known to cleave itself, undergoes only a single turnover, and after proteolysis, retains its substrate in its active site as an auto-inhibitor. The methods presented here describe an assay which overcomes these challenges.

Stepwise processing analyses of the single-turnover PCSK9 protease reveal its substrate sequence specificity and link clinical genotype to lipid phenotype.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) down-regulates the low-density lipoprotein (LDL) receptor, elevating LDL cholesterol and accelerating atherosclerotic heart disease, making it a promising cardiovascular drug target. To achieve its maximal effect on the LDL receptor, PCSK9 requires autoproteolysis. After cleavage, PCSK9 retains its prodomain in the active site as a self-inhibitor.

An Educational and Administrative Intervention to Promote Rational Laboratory Test Ordering on an Academic General Medicine Service.

Background: Overuse of clinical laboratory testing in the inpatient setting is a common problem. The objective of this project was to develop an inexpensive and easily implemented intervention to promote rational laboratory use without compromising resident education or patient care.

Methods: The study comprised of a cluster-randomized, controlled trial to assess the impact of a multifaceted intervention of education, guideline development, elimination of recurring laboratory orders, unbundling of laboratory panels, and redesign of the daily progress note on laboratory test ordering.

The proprotein convertase subtilisin/kexin type 9 (PCSK9) active site and cleavage sequence differentially regulate protein secretion from proteolysis.

Biologic-based strategies to inhibit proprotein convertase subtilisin/kexin type 9 (PCSK9) show promise as anti-hypercholesterolemic and, therefore, anti-atherosclerotic therapies. Despite substantial effort, no small molecule strategy to inhibit PCSK9 has demonstrated feasibility. In this study we interrogated the chemistry of the PCSK9 active site and its adjacent residues to identify a foothold with which to drug the PCSK9 processing pathway and ultimately disrupt the interaction with the LDL receptor.

Brain natriuretic peptide predicts functional outcome in ischemic stroke.

Background And Purpose: Elevated serum levels of brain natriuretic peptide (BNP) have been associated with cardioembolic stroke and increased poststroke mortality. We sought to determine whether BNP levels were associated with functional outcome after ischemic stroke.

Methods: We measured BNP in consecutive patients aged ≥ 18 years admitted to our stroke unit between 2002 to 2005.

Vesicular stomatitis viruses resistant to the methylase inhibitor sinefungin upregulate RNA synthesis and reveal mutations that affect mRNA cap methylation.

Sinefungin (SIN), a natural S-adenosyl-L-methionine analog produced by Streptomyces griseolus, is a potent inhibitor of methyltransferases. We evaluated the effect of SIN on replication of vesicular stomatitis virus (VSV), a prototype of the nonsegmented negative-strand RNA viruses. The 241-kDa large polymerase (L) protein of VSV methylates viral mRNA cap structures at the guanine-N-7 (G-N-7) and ribose-2'-O (2'-O) positions.

Quinolone-based IMPDH inhibitors: introduction of basic residues on ring D and SAR of the corresponding mono, di and benzofused analogues.

The synthesis and the structure-activity relationships (SAR) of analogues derived from the introduction of basic residues on ring D of quinolone-based inhibitors of IMPDH are described. This led to the identification of compound 27 as a potent inhibitor of IMPDH with significantly improved aqueous solubility over the lead compound 1.

Novel inhibitors of IMPDH: a highly potent and selective quinolone-based series.

A series of novel quinolone-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are described.