I8-arachnotocin–an arthropod-derived G protein-biased ligand of the human vasopressin V2 receptor

Abstract

The neuropeptides oxytocin (OT) and vasopressin (VP) and their G protein-coupled receptors OTR, V1aR, V1bR, and V2R form an important and widely-distributed neuroendocrine signaling system. In mammals, this signaling system regulates water homeostasis, blood pressure, reproduction, as well as social behaviors such as pair bonding, trust and aggression. There exists high demand for ligands with differing pharmacological profiles to study the physiological and pathological functions of the individual receptor subtypes. Here, we present the pharmacological characterization of an arthropod (Metaseiulus occidentalis) OT/VP-like nonapeptide across the human OT/VP receptors. I8-arachnotocin is a full agonist with respect to second messenger signaling at human V2R (EC50 34 nM) and V1bR (EC50 1.2 µM), a partial agonist at OTR (EC50 790 nM), and a competitive antagonist at V1aR [pA2 6.25 (558 nM)]. Intriguingly, I8-arachnotocin activated the Gαs pathway of V2R without recruiting either β-arrestin-1 or β-arrestin-2. I8-arachnotocin might thus be a novel pharmacological tool to study the (patho)physiological relevance of β-arrestin-1 or -2 recruitment to the V2R. These findings furthermore highlight arthropods as a novel, vast and untapped source for the discovery of novel pharmacological probes and potential drug leads targeting neurohormone receptors.

Development of a Selective Peptide κ-Opioid Receptor Antagonist by Late-Stage Functionalization with Cysteine Staples

“…Antagonism of CSD-CH 2 (1,8) -NH 2 at KOR was evaluated by the Schild regression analysis as previously described. 50 Briefly, the concentration−response curves of U50,488 were measured in the presence and absence of CSD-CH 2(1,8) -NH 2 . The cells were pretreated with CSD-CH 2(1,8) -NH 2 (0.3, 1, 3, and 10 μM) for 30 min at 37 °C, followed by co-incubation with U50,488 for an additional 30 min at 37 °C.…”

“…The BRET assay was performed as previously described . Briefly, human β-arrestin-2-nano luciferase (Nluc) and mouse KOR-EGFP were transiently expressed in HEK293 cells following co-transfection in a 1:10 ratio.…”

The oxytocin receptor signalling system and breast cancer: a critical review

“…Bioactive OT/VP-like peptides from natural sources form promising starting points for the identification of pharmaceutical lead compounds, a strategy that our laboratories have pursued now for many years [ 7 ]. It takes advantage of the evolutionary conservation of this signalling system across the animal kingdom and provides high hit-rates for the discovery of bioactive OT ligands with often unique and therapeutically relevant pharmacology [ 8 , 136 , 145 – 147 ]. These ligands play an important role in dissecting these cancer-related signalling pathways and, combined with state-of-the-art medicinal chemistry, also form exquisite starting points for drug development programs [ 103 , 148 – 151 ].…”

Neuropeptide signalling systems – An underexplored target for venom drug discovery

“…This diversity can be exploited to benefit human health as neuropeptides identified from different organisms represent a rich source for molecular probes and therapeutic leads to dissect neuropeptide signalling in health and disease. This hypothesis has been underpinned by multiple studies, including new oxytocin and vasopressin ligands identified from insects [69,70], salmon calcitonin used to treat hypercalcemia [71]; and pramlintide (based on rat amylin) to reduce blood glucose levels in type 1 and type 2 diabetes mellitus patients [72].…”