Delineation of a Conserved Arrestin-Biased Signaling Repertoire In Vivo

Abstract

Biased G protein-coupled receptor agonists engender a restricted repertoire of downstream events from their cognate receptors, permitting them to produce mixed agonist-antagonist effects in vivo. While this opens the possibility of novel therapeutics, it complicates rational drug design, since the in vivo response to a biased agonist cannot be reliably predicted from its in cellula efficacy. We have employed novel informatic approaches to characterize the in vivo transcriptomic signature of the arrestin pathway-selective parathyroid hormone analog [D-Trp ]bovine PTH(7-34) elicits a distinctive arrestinsignaling focused transcriptomic response that is more coherently regulated across tissues than that of the pluripotent agonist, human PTH(1-34). This arrestin-focused network is closely associated with transcriptional control of cell growth and development. Our demonstration of a conserved arrestin-dependent transcriptomic signature suggests a framework within which the in vivo outcomes of arrestin-biased signaling may be generalized.

Fulfilling the Promise of "Biased" G Protein–Coupled Receptor Agonism

“…As shown, at a gestalt level the global transcriptomic effects of hPTH(1-34) and (D-Trp 12 ,Tyr 34 )-bPTH(7-34) appear to be markedly different in wild-type mice, and although the effects of the G protein-competent conventional ligand are largely conserved between wild-type and arrestin3 null backgrounds, the loss of arrestin3 profoundly disrupts the effects of the arrestin-biased ligand. Similar divergence is evident when the transcriptomic effects of the two ligands are compared at the pathway level by geneset enrichment analysis (Gesty-Palmer et al, 2013;Maudsley et al, 2015a). Figure 2B illustrates the substantial degree of nonoverlap observed in calvarial bone after long-term hPTH(1-34) or (D-Trp 12 ,Tyr 34 )-bPTH(7-34) treatment.…”

“…Figure 2B illustrates the substantial degree of nonoverlap observed in calvarial bone after long-term hPTH(1-34) or (D-Trp 12 ,Tyr 34 )-bPTH(7-34) treatment. Unlike data from short-term phosphoproteomic surveys, transcriptomic datasets from six different tissues show only 1.4 to 38.9% commonality at the pathway level between conventional and arrestin biased PTH 1 R agonists (Maudsley et al, 2015a). Whereas in bone hPTH(1-34) primarily affects pathways classically associated with enhanced bone turnover, including collagen synthesis, matrix mineralization, and osteoclast activation, (D-Trp 12 , Tyr 34 )-bPTH(7-34) primarily affects pathways regulating cell cycle progression, cell survival, and migration (Gesty-Palmer et al, 2013).…”

“…In vivo, however, where drugs must exert their therapeutic effects, the limited systems level data available suggest that conventional and biased agonists may be dramatically different (Appleton and Luttrell, 2013). Figure 2A illustrates this point using the three-dimensional data visualization application Omnimorph (http://www.ott.nih.gov/technology/e-143-2010) to depict the transcriptomic fingerprint of the conventional PTH 1 R agonist hPTH(1-34) and the arrestin biased agonist (D-Trp 12 ,Tyr 34 )-bPTH(7-34) in the kidneys of mice exposed to vehicle or ligand for 4 weeks (Maudsley et al, 2015a). As shown, at a gestalt level the global transcriptomic effects of hPTH(1-34) and (D-Trp 12 ,Tyr 34 )-bPTH(7-34) appear to be markedly different in wild-type mice, and although the effects of the G protein-competent conventional ligand are largely conserved between wild-type and arrestin3 null backgrounds, the loss of arrestin3 profoundly disrupts the effects of the arrestin-biased ligand.…”

G Protein–Coupled Receptor Endocytosis Confers Uniformity in Responses to Chemically Distinct Ligands

“…For example, classic full agonist and biased partial agonist ligands produce markedly different integrated cellular responses through angiotensin II and parathyroid hormone receptors, as indicated by striking differences in the cell's phosphoproteomic or transcriptional responses (Christensen et al, 2010(Christensen et al, , 2011Gesty-Palmer et al, 2013;Maudsley et al, 2015;Santos et al, 2015). Evolutionarily, however, there is selective pressure for cells to generate a stereotyped output in response to the presence of a cognate ligand.…”

The Multiple Waves of Cannabinoid 1 Receptor Signaling

“…Recent advances on transcriptomics, signaling screenings, and computational analysis have allowed the assessment of b-arrestin-mediated signaling on a global scale. For example, b-arrestin-mediated transcriptomic signatures were shown to be conserved in vivo and in vitro, sometimes across multiple tissues, suggesting conserved biologic responses (Gesty-Palmer et al, 2013;Maudsley et al, 2015). Among them, there is a common core of biologic functions regulated by b-arrestins, such as cell growth and survival, as reported for the CB 1 R (DelgadoPeraza et al, 2016), and these core molecular targets could potentially mediate some of the long-term effects of CB1R activation.…”