The experimental power of FR900359 to study Gq-regulated biological processes.

Despite the discovery of heterotrimeric αβγ G proteins ∼25 years ago, their selective perturbation by cell-permeable inhibitors remains a fundamental challenge. Here we report that the plant-derived depsipeptide FR900359 (FR) is ideally suited to this task. Using a multifaceted approach we systematically characterize FR as a selective inhibitor of Gq/11/14 over all other mammalian Gα isoforms and elaborate its molecular mechanism of action. We also use FR to investigate whether inhibition of Gq proteins is an effective post-receptor strategy to target oncogenic signalling, using melanoma as a model system. FR suppresses many of the hallmark features that are central to the malignancy of melanoma cells, thereby providing new opportunities for therapeutic intervention. Just as pertussis toxin is used extensively to probe and inhibit the signalling of Gi/o proteins, we anticipate that FR will at least be its equivalent for investigating the biological relevance of Gq

A Cell-Permeable Inhibitor to Trap Gαq Proteins in the Empty Pocket Conformation

In spite of the crucial role of heterotrimeric G proteins as molecular switches transmitting signals from G protein-coupled receptors, their selective manipulation with small molecule, cell-permeable inhibitors still remains an unmet challenge. Here, we report that the small molecule BIM-46187, previously classified as pan-G protein inhibitor, preferentially silences Gαq signaling in a cellular context-dependent manner. Investigations into its mode of action reveal that BIM traps Gαq in the empty pocket conformation by permitting GDP exit but interdicting GTP entry, a molecular mechanism not yet assigned to any other small molecule Gα inhibitor to date. Our data show that Gα proteins may be “frozen” pharmacologically in an intermediate conformation along their activation pathway and propose a pharmacological strategy to specifically silence Gα subclasses with cell-permeable inhibitors

Diastolic dysfunction in individuals with and without heart failure with preserved ejection fraction

Aim!#!Left ventricular diastolic dysfunction (DD), a common finding in the general population, is considered to be associated with heart failure with preserved ejection faction (HFpEF). Here we evaluate the prevalence and correlates of DD in subjects with and without HFpEF in a middle-aged sample of the general population.!##!Methods and results!#!From the first 10,000 participants of the population-based Hamburg City Health Study (HCHS), 5913 subjects (mean age 64.4 ± 8.3 years, 51.3% females), qualified for the current analysis. Diastolic dysfunction (DD) was identified in 753 (12.7%) participants. Of those, 11.2% showed DD without HFpEF (ALVDD) while 1.3% suffered from DD with HFpEF (DDwHFpEF). In multivariable regression analysis adjusted for major cardiovascular risk factors, ALVDD was associated with arterial hypertension (OR 2.0, p < 0.001) and HbA1c (OR 1.2, p = 0.007). Associations of both ALVDD and DDwHFpEF were: age (OR 1.7, p < 0.001; OR 2.7, p < 0.001), BMI (OR 1.2, p < 0.001; OR 1.6, p = 0.001), and left ventricular mass index (LVMI). In contrast, female sex (OR 2.5, p = 0.006), atrial fibrillation (OR 2.6, p = 0.024), CAD (OR 7.2, p < 0.001) COPD (OR 3.9, p < 0.001), and QRS duration (OR 1.4, p = 0.005) were strongly associated with DDwHFpEF but not with ALVDD.!##!Conclusion!#!The prevalence of DD in a sample from the first 10,000 participants of the population-based HCHS was 12.7% of whom 1.3% suffered from HFpEF. DD with and without HFpEF showed significant associations with different major cardiovascular risk factors and comorbidities warranting further research for their possible role in the formation of both ALVDD and DDwHFpEF

Heart failure in the general population and impact of the 2021 European Society of Cardiology Heart Failure Guidelines

Abstract Aim The diagnosis of heart failure (HF) has been refined in several steps in recent years, reflecting evolving diagnostic and therapeutic approaches. The European Society of Cardiology (ESC) recently published a modified definition of HF in the 2021 heart failure (HF) guidelines. The impact of this new diagnostic algorithm on the prevalence of HF is not known. The aim of this study was to describe the contemporary prevalence of HF in a representative, completely phenotyped sample from the general population. Methods and results This analysis was conducted among 7074 participants (aged 45–78 years, 51.5% women) from the population‐based Hamburg City Health Study. Compared with the 2016 version, HF prevalence increased with the 2021 HF guidelines from 4.31% to 4.83% (12% increase). This increase was driven by a higher number of subjects with HF with reduced/mildly‐reduced ejection fraction (0.47% to 0.52%; 1.37% to 2.12%), while the number of subjects with HF with preserved ejection fraction decreased from 2.46% to 2.19%. Importantly, this did not impact the known risk factor profiles of the phenotypes. Although four drugs are recommended for all subjects with HFrEF in the new guidelines, several adjunctive therapies are recommended for dedicated cases/scenarios (e.g. <1% eligibility for ivabradine/vericiguat/devices). Conclusion Heart failure remains common in a contemporary general population sample. The number of patients with HF will increase when the current diagnostic criteria are applied. This offers opportunities to initiate preventive therapies, especially in patients with HFmrEF and HFrEF

Expression Analysis of CB2-GFP BAC Transgenic Mice

<div><p>The endocannabinoid system (ECS) is a retrograde messenger system, consisting of lipid signaling molecules that bind to at least two G-protein-coupled receptors, Cannabinoid receptor 1 and 2 (CB1 and 2). As CB2 is primarily expressed on immune cells such as B cells, T cells, macrophages, dendritic cells, and microglia, it is of great interest how CB2 contributes to immune cell development and function in health and disease. Here, understanding the mechanisms of CB2 involvement in immune-cell function as well as the trafficking and regulation of CB2 expressing cells are crucial issues. Up to now, CB2 antibodies produce unclear results, especially those targeting the murine protein. Therefore, we have generated BAC transgenic GFP reporter mice (CB2-GFPTg) to trace CB2 expression <i>in vitro</i> and <i>in situ</i>. Those mice express GFP under the CB2 promoter and display GFP expression paralleling CB2 expression on the transcript level in spleen, thymus and brain tissue. Furthermore, by using fluorescence techniques we show that the major sources for GFP-CB2 expression are B cells in spleen and blood and microglia in the brain. This novel CB2-GFP transgenic reporter mouse line represents a powerful resource to study CB2 expression in different cell types. Furthermore, it could be used for analyzing CB2-mediated mobilization and trafficking of immune cells as well as studying the fate of recruited immune cells in models of acute and chronic inflammation.</p></div

Enhanced GFP expression in stimulated splenic B cells.

<p>Splenocytes of WT and CB2-GFPTg mice were stimulated with LPS or CpG and GFP expression was analyzed by flow cytometry. GFP expression is significantly enhanced after stimulation in CB2-GFP mice (a,c) but not in WT mice (a). The number of B220⁺ cells is not altered by stimulation with LPS or CpG (b). N = 3, all samples were analyzed in triplicates. Data were analyzed by Students T-Test, *p < 0.05, **p < 0.001, to unstimulated genotype control.</p