Recent advances in the biology of bombesin-like peptides and their receptors.

Abstract

The current review aims to update the important findings about molecular and cellular biology of mammalian bombesin-like peptides (BLPs) and their receptors. Recent identification of synaptic communication between gastrin-releasing peptide (GRP) neurons and GRP receptor (GRPR) neurons in spinal itch relay provides us novel insights into physiology of itch sensation. Neuromedin B (NMB) neurons were found to form connections with subcortical areas associated with arousal, hippocampal theta oscillation, and premotor processing and project to multiple downstream stations to regulate locomotion and hippocampal theta power. In addition to researches regarding the roles of BLPs and their receptors in central nervous system, recent findings reveal that NMB receptor is expressed on helminth-induced type 2 innate lymphoid cells and is regulated by basophils, suggesting an important function of NMB in helminth-induced immune responses. Bombesin transactivates epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and HER3 receptors on human nonsmall-cell lung cancer (NSCLC) cells and elicits downstream signaling cascades and induces formation of both human epidermal growthfactor receptor 3 (HER3)/EGFR and HER3/HER2 heterodimers. Several high-affinity ligands for bombesin receptors were characterized, providing useful tools in investigation of biological roles of those peptides and their receptors. The most exciting findings of BLPs and their receptors in the past year come from studies in central nervous system. In addition, more researches are still underway to probe the molecular mechanisms of those peptides in peripheral tissues and characterize novel synthetic ligands with high affinity for mammalian bombesin receptors.