LGR signaling mediates muscle-adipose tissue crosstalk and protects against diet-induced insulin resistance.

Obesity impairs tissue insulin sensitivity and signaling, promoting type-2 diabetes. Although improving insulin signaling is key to reversing diabetes, the multi-organ mechanisms regulating this process are poorly defined. Here, we screen the secretome and receptome in Drosophila to identify the hormonal crosstalk affecting diet-induced insulin resistance and obesity.

NN1213 - A Potent, Long-Acting, and Selective Analog of Human Amylin.

Amylin, a member of the calcitonin family, acts via amylin receptors in the hindbrain and hypothalamus to suppress appetite. Native ligands of these receptors are peptides with short half-lives. Conjugating fatty acids to these peptides can increase their half-lives.

Development of Cagrilintide, a Long-Acting Amylin Analogue.

A hallmark of the pancreatic hormone amylin is its high propensity toward the formation of amyloid fibrils, which makes it a challenging drug design effort. The amylin analogue pramlintide is commercially available for diabetes treatment as an adjunct to insulin therapy but requires three daily injections due to its short half-life. We report here the development of the stable, lipidated long-acting amylin analogue cagrilintide () and some of the structure-activity efforts that led to the selection of this analogue for clinical development with obesity as an indication.

Positive Allosteric Modulators of Metabotropic Glutamate Receptor 5 as Tool Compounds to Study Signaling Bias.

Positive allosteric modulation of metabotropic glutamate subtype 5 (mGlu) receptor has emerged as a potential new therapeutic strategy for the treatment of schizophrenia and cognitive impairments. However, positive allosteric modulator (PAM) agonist activity has been associated with adverse side effects, and neurotoxicity has also been observed for pure PAMs. The structural and pharmacological basis of therapeutic versus adverse mGlu PAM in vivo effects remains unknown.

Evaluation of VGF peptides as potential anti-obesity candidates in pre-clinical animal models.

VGF is a peptide precursor expressed in neuroendocrine cells that is suggested to play a role in the regulation of energy homeostasis. VGF is proteolytically cleaved to yield multiple bioactive peptides. However, the specific actions of VGF-derived peptides on energy homeostasis remain unclear.

Detailed In Vitro Pharmacological Characterization of Clinically Tested Negative Allosteric Modulators of the Metabotropic Glutamate Receptor 5.

Negative allosteric modulation of the metabotropic glutamate 5 (mGlu) receptor has emerged as a potential strategy for the treatment of neurologic disorders. Despite the success in preclinical studies, many mGlu negative allosteric modulators (NAMs) that have reached clinical trials failed due to lack of efficacy. In this study, we provide a detailed in vitro pharmacological characterization of nine clinically and preclinically tested NAMs.

A fat-tissue sensor couples growth to oxygen availability by remotely controlling insulin secretion.

Organisms adapt their metabolism and growth to the availability of nutrients and oxygen, which are essential for development, yet the mechanisms by which this adaptation occurs are not fully understood. Here we describe an RNAi-based body-size screen in Drosophila to identify such mechanisms. Among the strongest hits is the fibroblast growth factor receptor homolog breathless necessary for proper development of the tracheal airway system.

Role of age, Rho-kinase 2 expression, and G protein-mediated signaling in the myogenic response in mouse small mesenteric arteries.

Unlabelled: The myogenic response (MR) and myogenic tone (MT) in resistance vessels is crucial for maintaining peripheral vascular resistance and blood flow autoregulation. Development of MT involves G protein-coupled receptors, and may be affected by aging.

Aims: (1) to estimate the mesenteric blood flow in myogenically active small mesenteric arteries; (2) to investigate the signaling from G and/or G activation to MT development; (3) to investigate the role of Rho-kinase 2 and aging on MT in mesenteric resistance arteries.

[Sar1, Ile4, Ile8]-angiotensin II Potentiates Insulin Receptor Signalling and Glycogen Synthesis in Hepatocytes.

The angiotensin II type I receptor (AT1R) is involved in the regulation of cardiovascular function. Excessive activation of AT1R by angiotensin II (Ang II) leads to cardiovascular disease and may be involved in the development of insulin resistance and diabetes. Functionally selective Ang II analogues, such as the [Sar1, Ile4, Ile8]-angiotensin II (SII Ang II) analogue, that only activate a subset of signalling networks have been demonstrated to have beneficial effects on cardiovascular function in certain settings, including lowering blood pressure and increasing cardiac performance.

A bioluminescence resonance energy transfer 2 (BRET2) assay for monitoring seven transmembrane receptor and insulin receptor crosstalk.

The angiotensin AT receptor is a seven transmembrane (7TM) receptor, which mediates the regulation of blood pressure. Activation of angiotensin AT receptor may lead to impaired insulin signaling indicating crosstalk between angiotensin AT receptor and insulin receptor signaling pathways. To elucidate the molecular mechanisms behind this crosstalk, we applied the BRET technique to monitor the effect of angiotensin II on the interaction between Rluc tagged insulin receptor and GFP tagged insulin receptor substrates 1, 4, 5 (IRS1, IRS4, IRS5) and Src homology 2 domain-containing protein (Shc).

Type II Turn of Receptor-bound Salmon Calcitonin Revealed by X-ray Crystallography.

Calcitonin is a peptide hormone consisting of 32 amino acid residues and the calcitonin receptor is a Class B G protein-coupled receptor (GPCR). The crystal structure of the human calcitonin receptor ectodomain (CTR ECD) in complex with a truncated analogue of salmon calcitonin ([BrPhe(22)]sCT(8-32)) has been determined to 2.1-Å resolution.

Dual agonist occupancy of AT1-R-α2C-AR heterodimers results in atypical Gs-PKA signaling.

Hypersecretion of norepinephrine (NE) and angiotensin II (AngII) is a hallmark of major prevalent cardiovascular diseases that contribute to cardiac pathophysiology and morbidity. Herein, we explore whether heterodimerization of presynaptic AngII AT1 receptor (AT1-R) and NE α2C-adrenergic receptor (α2C-AR) could underlie their functional cross-talk to control NE secretion. Multiple bioluminescence resonance energy transfer and protein complementation assays allowed us to accurately probe the structures and functions of the α2C-AR-AT1-R dimer promoted by ligand binding to individual protomers.

Predicting kinase activity in angiotensin receptor phosphoproteomes based on sequence-motifs and interactions.

Recent progress in the understanding of seven-transmembrane receptor (7TMR) signalling has promoted the development of a new generation of pathway selective ligands. The angiotensin II type I receptor (AT1aR) is one of the most studied 7TMRs with respect to selective activation of the β-arrestin dependent signalling. Two complimentary global phosphoproteomics studies have analyzed the complex signalling induced by the AT1aR.

The 14q32 microRNA-487b targets the antiapoptotic insulin receptor substrate 1 in hypertension-induced remodeling of the aorta.

Objectives: To study the role of microRNAs in hypertension-induced vascular pathology before the onset of symptoms of severe cardiovascular disease.

Background: MicroRNAs play a crucial role in cardiovascular disease. However, microRNAs are often studied in full-blown cardiovascular disease models, not during development of cardiovascular pathology.

Functional enhancement of AT1R potency in the presence of the TPαR is revealed by a comprehensive 7TM receptor co-expression screen.

Background: Functional cross-talk between seven transmembrane (7TM) receptors can dramatically alter their pharmacological properties, both in vitro and in vivo. This represents an opportunity for the development of novel therapeutics that potentially target more specific biological effects while causing fewer adverse events. Although several studies convincingly have established the existence of 7TM receptor cross-talk, little is known about the frequencey and biological significance of this phenomenon.

Functionally selective AT(1) receptor activation reduces ischemia reperfusion injury.

Angiotensin II (AngII) is a key peptide in cardiovascular homeostasis and is a ligand for the Angiotensin II type 1 and 2 seven transmembrane receptors (AT(1)R and AT(2)R). The AT(1) receptor is a seven-transmembrane (7TM) G protein-coupled receptor (GPCR) mediating the majority of the physiological functions of AngII. The AT(1)R mediates its effects through both G protein-dependent and independent signaling, which can be separated by functionally selective agonists.

Deciphering biased-agonism complexity reveals a new active AT1 receptor entity.

Functional selectivity of G protein-coupled receptor (GPCR) ligands toward different downstream signals has recently emerged as a general hallmark of this receptor class. However, pleiotropic and crosstalk signaling of GPCRs makes functional selectivity difficult to decode. To look from the initial active receptor point of view, we developed new, highly sensitive and direct bioluminescence resonance energy transfer-based G protein activation probes specific for all G protein isoforms, and we used them to evaluate the G protein-coupling activity of [(1)Sar(4)Ile(8)Ile]-angiotensin II (SII), previously described as an angiotensin II type 1 (AT(1)) receptor-biased agonist that is G protein independent but β-arrestin selective.

A BRET assay for monitoring insulin receptor interactions and ligand pharmacology.

The insulin receptor (IR) belongs to the receptor tyrosine kinase super family and plays an important role in glucose homeostasis. The receptor interacts with several large docking proteins that mediate signaling from the receptor, including the insulin receptor substrate (IRS) family and Src homology-2-containing proteins (Src). Here, we applied the bioluminescence resonance energy transfer 2 (BRET2) technique to study the IR signaling pathways.

SNPs in microRNA binding sites in 3'-UTRs of RAAS genes influence arterial blood pressure and risk of myocardial infarction.

Background: We hypothesized that single nucleotide polymorphisms (SNPs) located in microRNA (miR) binding sites in genes of the renin angiotensin aldosterone system (RAAS) can influence blood pressure and risk of myocardial infarction.

Methods: Using online databases dbSNP and TargetScan, we identified 10 SNPs in potential miR binding sites in eight RAAS-related genes, common in Caucasians. We genotyped a large case-control study on myocardial infarctions, the Study of Myocardial Infarctions LEiden (SMILE) for these 10 SNPs and found nine SNPs, in seven genes, to be prevalent.

Cell-specific detection of microRNA expression during cardiomyogenesis by combined in situ hybridization and immunohistochemistry.

MicroRNAs (miRNAs) regulate gene expression by mediating translational repression or mRNA degradation of their targets, and several miRNAs control developmental decisions through embryogenesis. In the developing heart, miRNA targets comprise key players mediating cardiac lineage determination. However, although several miRNAs have been identified as differentially regulated during cardiac development and disease, their distinct cell-specific localization remains largely undetermined, likely owing to a lack of adequate methods.

Angiotensin II type 1 receptor signalling regulates microRNA differentially in cardiac fibroblasts and myocytes.

Background And Purpose: The angiotensin II type 1 receptor (AT(1)R) is a key regulator of blood pressure and cardiac contractility and is profoundly involved in development of cardiac disease. Since several microRNAs (miRNAs) have been implicated in cardiac disease, we determined whether miRNAs might be regulated by AT(1)R signals in a Gαq/11-dependent or -independent manner.

Experimental Approach: We performed a global miRNA array analysis of angiotensin II (Ang II)-mediated miRNA regulation in HEK293N cells overexpressing the AT(1)R and focused on separating the role of Gαq/11-dependent and -independent pathways.

Biased signaling of the angiotensin II type 1 receptor can be mediated through distinct mechanisms.

Background: Seven transmembrane receptors (7TMRs) can adopt different active conformations facilitating a selective activation of either G protein or β-arrestin-dependent signaling pathways. This represents an opportunity for development of novel therapeutics targeting selective biological effects of a given receptor. Several studies on pathway separation have been performed, many of these on the Angiotensin II type 1 receptor (AT1R).

The angiotensin II type 1 receptor antagonist Losartan binds and activates bradykinin B2 receptor signaling.

The angiotensin II type 1 receptor (AT1R) blocker (ARB) Losartan has cardioprotective effects during ischemia-reperfusion injury and inhibits reperfusion arrhythmias -effects that go beyond the benefits of lowering blood pressure. The renin-angiotensin and kallikrein-kinin systems are intricately connected and some of the cardioprotective effects of Losartan are abolished by blocking the bradykinin B2 receptor (B2R) signaling. In this study, we investigated the ability of six clinically available ARBs to specifically bind and activate the B2R.

Therapeutic potential of functional selectivity in the treatment of heart failure.

Adrenergic and angiotensin receptors are prominent targets in pharmacological alleviation of cardiac remodeling and heart failure, but their use is associated with cardiodepressant side effects. Recent advances in our understanding of seven transmembrane receptor signaling show that it is possible to design ligands with "functional selectivity," acting as agonists on certain signaling pathways while antagonizing others. This represents a major pharmaceutical opportunity to separate desired from adverse effects governed by the same receptor.