Mechanisms of actin filament severing and elongation by formins.

Humans express 15 formins that play crucial roles in actin-based processes, including cytokinesis, cell motility and mechanotransduction. However, the lack of structures bound to the actin filament (F-actin) has been a major impediment to understanding formin function. Whereas formins are known for their ability to nucleate and elongate F-actin, some formins can additionally depolymerize, sever or bundle F-actin.

Molecular mechanisms linking missense ACTG2 mutations to visceral myopathy.

Visceral myopathy is a life-threatening disease characterized by muscle weakness in the bowel, bladder, and uterus. Mutations in smooth muscle γ-actin (ACTG2) are the most common cause of the disease, but the mechanisms by which the mutations alter muscle function are unknown. Here, we examined four prevalent ACTG2 mutations (R40C, R148C, R178C, and R257C) that cause different disease severity and are spread throughout the actin fold.

Optical Control of G-Actin with a Photoswitchable Latrunculin.

Actin is one of the most abundant proteins in eukaryotic cells and is a key component of the cytoskeleton. A range of small molecules has emerged that interfere with actin dynamics by either binding to polymeric F-actin or monomeric G-actin to stabilize or destabilize filaments or prevent their formation and growth, respectively. Among these, the latrunculins, which bind to G-actin and affect polymerization, are widely used as tools to investigate actin-dependent cellular processes.

Fragment-Based Discovery of Allosteric Inhibitors of SH2 Domain-Containing Protein Tyrosine Phosphatase-2 (SHP2).

The ubiquitously expressed protein tyrosine phosphatase SHP2 is required for signaling downstream of receptor tyrosine kinases (RTKs) and plays a role in regulating many cellular processes. Genetic knockdown and pharmacological inhibition of SHP2 suppresses RAS/MAPK signaling and inhibit the proliferation of RTK-driven cancer cell lines. Here, we describe the first reported fragment-to-lead campaign against SHP2, where X-ray crystallography and biophysical techniques were used to identify fragments binding to multiple sites on SHP2.

Ensembles of human myosin-19 bound to calmodulin and regulatory light chain RLC12B drive multimicron transport.

Myosin-19 (Myo19) controls the size, morphology, and distribution of mitochondria, but the underlying role of Myo19 motor activity is unknown. Complicating mechanistic in vitro studies, the identity of the light chains (LCs) of Myo19 remains unsettled. Here, we show by coimmunoprecipitation, reconstitution, and proteomics that the three IQ motifs of human Myo19 expressed in Expi293 human cells bind regulatory light chain (RLC12B) and calmodulin (CaM).

Network Models and Simulation Analytics for Multi-scale Dynamics of Biological Invasions.

Globalization and climate change facilitate the spread and establishment of invasive species throughout the world via multiple pathways. These spread mechanisms can be effectively represented as diffusion processes on multi-scale, spatial networks. Such network-based modeling and simulation approaches are being increasingly applied in this domain.

Patient preferences in retinal drug delivery.

Retinal vascular diseases (RVDs) are often treated with intravitreally (IVT) injected drugs, with relatively low patient compliance and potential risks. Ongoing research explores alternative RVD treatments, including eye drops and oral tablets. This study surveyed RVD patients treated with IVT injections to establish factors influencing low compliance rates while gauging treatment delivery method preferences.

Discovery of ASTX029, A Clinical Candidate Which Modulates the Phosphorylation and Catalytic Activity of ERK1/2.

Aberrant activation of the mitogen-activated protein kinase pathway frequently drives tumor growth, and the ERK1/2 kinases are positioned at a key node in this pathway, making them important targets for therapeutic intervention. Recently, a number of ERK1/2 inhibitors have been advanced to investigational clinical trials in patients with activating mutations in B-Raf proto-oncogene or Ras. Here, we describe the discovery of the clinical candidate ASTX029 () through structure-guided optimization of our previously published isoindolinone lead ().

Patient perspectives of target weight management and ultrafiltration in haemodialysis: a multi-center survey.

Background: Decisions around planned ultrafiltration volumes are the only part of the haemodialysis prescription decided upon at every session. Removing too much fluid or too little is associated with both acute symptoms and long-term outcomes. The degree to which patients engage with or influence decision-making is not clear.

Molecular Dynamics for Antimicrobial Peptide Discovery.

Although antimicrobial resistance is an increasingly significant public health concern, there have only been two new classes of antibiotics approved for human use since the 1960s. Understanding the mechanisms of action of antibiotics is critical for novel antibiotic discovery, but novel approaches are needed that do not exclusively rely on experiments. Molecular dynamics simulation is a computational tool that uses simple models of the atoms in a system to discover nanoscale insights into the dynamic relationship between mechanism and biological function.

Non-Equilibrium Mass Exchange in AOT Reverse Micelles.

Reverse micelles (RMs) composed of water and sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in isooctane have a remarkably narrow size distribution around a mean value determined by the water loading ratio of the system. It has been proposed that RMs establish this equilibrium size distribution either by the diffusion of individual components through the isooctane phase or by cycles of fusion and fission. To examine these mechanisms, a 24 μs all-atom molecular dynamics simulation of a system containing one small RM and one large RM was performed.

DPP1 Inhibitors: Exploring the Role of Water in the S2 Pocket of DPP1 with Substituted Pyrrolidines.

A series of pyrrolidine amino nitrile DPP1 inhibitors have been developed and characterized. The S2 pocket structure-activity relationship for these compounds shows significant gains in potency for DPP1 from interacting further with target residues and a network of water molecules in the binding pocket. Herein we describe the X-ray crystal structures of several of these compounds alongside an analysis of factors influencing the inhibitory potency toward DPP1 of which stabilization of the water network, demonstrated using Grand Canonical Monte Carlo simulations and free energy calculations, is attributed as a main factor.

Conditional mutagenesis by oligonucleotide-mediated integration of loxP sites in zebrafish.

Many eukaryotic genes play essential roles in multiple biological processes in several different tissues. Conditional mutants are needed to analyze genes with such pleiotropic functions. In vertebrates, conditional gene inactivation has only been feasible in the mouse, leaving other model systems to rely on surrogate experimental approaches such as overexpression of dominant negative proteins and antisense-based tools.

Renal association clinical practice guideline in post-operative care in the kidney transplant recipient.

These guidelines cover the care of patients from the period following kidney transplantation until the transplant is no longer working or the patient dies. During the early phase prevention of acute rejection and infection are the priority. After around 3-6 months, the priorities change to preservation of transplant function and avoiding the long-term complications of immunosuppressive medication (the medication used to suppress the immune system to prevent rejection).

Evading the fate of Pheidippides: acute coronary thrombosis in a young marathon runner with minimal atherosclerosis but sickle cell trait.

Marathon running transiently increases the risk of sudden cardiac death. Some previous studies have suggested that this is due to relatively advanced but asymptomatic atherosclerosis. Other theories suggest that potentiation of inflammation and the coagulation cascade, by extremes of exertion, is more important.

Retrograde Wiring of Collateral Channels of the Heart in Chronic Total Occlusions: A Systematic Review and Meta-Analysis of Safety, Feasibility, and Incremental Value in Achieving Revascularization.

Aim: To conduct a systematic review and meta-analysis on retrograde wiring in chronic total occlusions (CTOs) with focus on its safety and feasibility.

Methods And Results: We searched publications from 1990 to December 2013 in PubMed, Ovid, EMBASE, and the Cochrane database inserting a number of terms relating to the collateral circulation of the heart in CTOs. A total of 18 case series (n range17-462) with a total of 2280 CTO revascularization attempts fulfilled criteria for a study of retrograde wiring of collateral channels in CTOs.

Site-specific intravascular ultrasound analysis of remodelling index and calcified necrosis patterns reveals novel blueprints for coronary plaque instability.

Aims: Post-mortem pathological studies have shown that a "vulnerable" plaque is the dominant patho-physiological mechanism responsible for acute coronary syndromes (ACS). One way to improve our understanding of these plaques in vivo is by using histological "surrogates" created by intravascular ultrasound derived virtual histology (IVUS-VH). Our aim in this analysis was to determine the relationship between site-specific differences in individual plaque areas between ACS plaques and stable plaques (SP), with a focus on remodelling index and the pattern of calcifying necrosis.

Identification of a series of compounds with potent antiviral activity for the treatment of enterovirus infections.

Rhinovirus (genus enterovirus) infections are responsible for many of the severe exacerbations of asthma and chronic obstructive pulmonary disease. Other members of the genus can cause life-threatening acute neurological infections. There is currently no antiviral drug approved for the treatment of such infections.

Construction and validation of a plaque discrimination score from the anatomical and histological differences in coronary atherosclerosis: the Liverpool IVUS-V-HEART (Intra Vascular UltraSound-Virtual-Histology Evaluation of Atherosclerosis Requiring Treatment) study.

Aims: New markers to help stratify coronary atherosclerosis are needed. Although attempts have been made to differentiate active lesions from those that are stable, none of these has ever been formalised into a discriminatory score. The aim of this study was to analyse the differences between culprit ACS lesions and culprit stable angina lesions with intravascular ultrasound-derived virtual histology and to construct and validate a plaque score.

Design, synthesis and biological evaluation of α-substituted isonipecotic acid benzothiazole analogues as potent bacterial type II topoisomerase inhibitors.

The discovery and optimisation of a new class of benzothiazole small molecules that inhibit bacterial DNA gyrase and topoisomerase IV are described. Antibacterial properties have been demonstrated by activity against DNA gyrase ATPase and potent activity against Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes and Haemophilus influenzae. Further refinements to the scaffold designed to enhance drug-likeness included analogues bearing an α-substituent to the carboxylic acid group, resulting in excellent solubility and favourable pharmacokinetic properties.

A novel, broad-spectrum inhibitor of enterovirus replication that targets host cell factor phosphatidylinositol 4-kinase IIIβ.

Despite their high clinical and socioeconomic impacts, there is currently no approved antiviral therapy for the prophylaxis or treatment of enterovirus infections. Here we report on a novel inhibitor of enterovirus replication, compound 1, 2-fluoro-4-(2-methyl-8-(3-(methylsulfonyl)benzylamino)imidazo[1,2-a]pyrazin-3-yl)phenol. This compound exhibited a broad spectrum of antiviral activity, as it inhibited all tested species of enteroviruses and rhinoviruses, with 50% effective concentrations ranging between 4 and 71 nM.

FIRST: Fractional Flow Reserve and Intravascular Ultrasound Relationship Study.

Objectives: FIRST (Fractional Flow Reserve and Intravascular Ultrasound Relationship Study) aimed to determine the optimal minimum lumen area (MLA) by intravascular ultrasound (IVUS) that correlates with fractional flow reserve (FFR) and to assess the correlation between virtual histology IVUS and FFR for intermediate coronary lesions.

Background: FFR is considered the gold standard for assessing intermediate coronary lesions. Measurements of ≤0.

Defining the magnitude of measurement variability in the virtual histology analysis of acute coronary syndrome plaques.

Background: Previous intravascular ultrasound-based virtual histology (IVUS-VH) measurement variability studies have been confined to single-frame or short-segment analysis in stable patients with minimal disease. We sought to determine the magnitude of human measurement variability in acute coronary syndrome (ACS) plaques.

Methods And Results: Prior to percutaneous coronary intervention, we performed IVUS-VH analysis in troponin-positive ACS culprit lesions.