GPR40 Receptor Activation Promotes Tight Junction Assembly in Airway Epithelial Cells via AMPK-dependent Mechanisms

Aekkacha Moonwiriyakit, Panisara Wattanaphichet, Varanuj Chatsudthipong, Chatchai Muanprasat

Tissue Barriers. 2018;6(2):1-12.

PMID: 29913106

Abstract:

Tight junctions play key roles in the regulation of airway epithelial barrier function and promotion of tight junction integrity is beneficial to lung health. G-protein coupled receptor (GPR) 40 has been identified as a receptor of polyunsaturated fatty acids. This study aimed to investigate the function of GPR40 in regulating tight junction assembly in human airway epithelial cells (Calu-3 cells) using GW9508, a GPR40 agonist. Immunoblotting and immunofluorescence analyses showed that Calu-3 cells expressed both types of polyunsaturated fatty acid receptors including GPR40 and GPR120. Intracellular Ca2+ measurements confirmed that GW9508 stimulated GPR40, but not GPR120. In Ca2+ switch assays, GW9508 promoted the recovery of transepithelial electrical resistance and re-localization of zonula occludens (ZO)-1 to intercellular areas. These effects were suppressed by inhibitors of GPR40 and phospholipase C (PLC). Interestingly, GW9508 enhanced tight junction assembly in an AMP-activated protein kinase (AMPK)-dependent manner. The effect of GW9508 on inducing tight junction assembly was also confirmed in 16HBE14o- cells. Our results indicate that GPR40 stimulation by GW9508 leads to AMPK activation via calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ). Collectively, this study reveals an unprecedented role of GPR40 in facilitating airway epithelial tight junction assembly via PLC-CaMKKβ-AMPK pathways. GPR40 represents a novel regulator of airway epithelial integrity and its stimulation may be beneficial in the treatment of airway diseases.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP885101893-B	GW9508		885101-89-3	Price