In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.

Input: Consider Input: Ligand-directed signal bias offers opportunities for sculpting molecular events, with the promise of better, safer therapeutics. Critical to the exploitation of signal bias is an understanding of the molecular events coupling ligand binding to intracellular signaling. Activation of class B G protein-coupled receptors is driven by interaction of the peptide N terminus with the receptor core. To understand how this drives signaling, we have used advanced analytical methods that enable separation of effects on pathway-specific signaling from those that modify agonist affinity and mapped the functional consequence of receptor modification onto three-dimensional models of a receptor-ligand complex. This yields molecular insights into the initiation of receptor activation and the mechanistic basis for biased agonism. Our data reveal that peptide agonists can engage different elements of the receptor extracellular face to achieve effector coupling and biased signaling providing a foundation for rational design of biased agonists.

Output: The Extracellular Surface of the GLP-1 Receptor Is a Molecular Trigger for Biased Agonism

Input: Consider Input: A population of fibro/adipogenic but non-myogenic progenitors located between skeletal muscle fibers was recently discovered. The aim of this study was to determine the extent to which these progenitors differentiate into fully functional adipocytes. The characterization of muscle progenitor-derived adipocytes is a central issue in understanding muscle homeostasis. They are considered as being the cellular origin of intermuscular adipose tissue that develops in several pathophysiological situations. Here fibro/adipogenic progenitors were isolated from a panel of 15 human muscle biopsies on the basis of the specific cell-surface immunophenotype CD15+/PDGFR+CD56-. This allowed investigations of their differentiation into adipocytes and the cellular functions of terminally differentiated adipocytes. Adipogenic differentiation was found to be regulated by the same effectors as those regulating differentiation of progenitors derived from white subcutaneous adipose tissue. Similarly, basic adipocyte functions, such as triglyceride synthesis and lipolysis occurred at levels similar to those observed with subcutaneous adipose tissue progenitor-derived adipocytes. However, muscle progenitor-derived adipocytes were found to be insensitive to insulin-induced glucose uptake, in association with the impairment of phosphorylation of key insulin-signaling effectors. Our findings indicate that muscle adipogenic progenitors give rise to bona fide white adipocytes that have the unexpected feature of being insulin-resistant.

Output: Characterization of adipocytes derived from fibro/adipogenic progenitors resident in human skeletal muscle

Input: Consider Input: Vascular calcification is a strong independent predictor of increased cardiovascular morbidity and mortality and has a high prevalence among patients with chronic kidney disease. The present study investigated the effects of quercetin on vascular calcification caused by oxidative stress and abnormal mitochondrial dynamics both in vitro and in vivo. Calcifying vascular smooth muscle cells (VSMCs) treated with inorganic phosphate (Pi) exhibited mitochondrial dysfunction, as demonstrated by decreased mitochondrial potential and ATP production. Disruption of mitochondrial structural integrity was also observed in a rat model of adenine-induced aortic calcification. Increased production of reactive oxygen species, enhanced expression and phosphorylation of Drp1, and excessive mitochondrial fragmentation were also observed in Pi-treated VSMCs. These effects were accompanied by mitochondria-dependent apoptotic events, including release of cytochrome c from the mitochondria into the cytosol and subsequent activation of caspase-3. Quercetin was shown to block Pi-induced apoptosis and calcification of VSMCs by inhibiting oxidative stress and decreasing mitochondrial fission by inhibiting the expression and phosphorylation of Drp1. Quercetin also significantly ameliorated adenine-induced aortic calcification in rats. In summary, our findings suggest that quercetin attenuates calcification by reducing apoptosis of VSMCs by blocking oxidative stress and inhibiting mitochondrial fission.
Output: Quercetin attenuates vascular calcification by inhibiting oxidative stress and mitochondrial fission.