Functional Expression Of The Purinergic Receptor P2Y14 In The (HLMVEC) And The Role In Tumour Development

The P2Y14 is a Gi-coupled receptor that inhibits the synthesis of cAMP, and is activated by UDP-glucose, UDP-galactose, and UDP-N-acetylglucosamine. Recent studies indicate the role of P2Y14 in modulating the immune function in T-lymphocytes and secretion of the proinflammatory cytokine IL-8 in airway epithelial cells. Furthermore, extracellular release of UDP-glucose was observed in thrombin-treated astrocytes suggesting that P2Y14 may be activated in inflammation.AIMThe aim of this study was to identify the functional expression of P2Y14 receptor in HLMVEC, and thus further demonstrated the mechanism of P2Y14 receptor in the occurrence and progressive of respiratory and blood diseases.METHODSWe used RT-PCR and western blot to investigate the mRNA and protein expression of P2Y14 receptor in the HLMVEC. The cAMP assay was used to identify the function of P2Y14 receptor under the P2Y14-specific substrate, UDP glucose, treatment in HLMVEC. Signaling studies show treatment of HLMVEC with UDP-glucose activates the Raf-1/MEK-1/ERKl/2 pathway. The ECIS (Electrical cell-substrate impedance sensing) was used to check the permeability of HLMVEC with UDP-glucose treatment.RESULTS1. Our data indicate for the first time that P2Y14 is expressed in endothelial cells (HLMVEC) as evidenced by RT-PCR, Western blot.2. The cAMP assay indicates that P2Y14 is functional in HLMVEC as an addition of the P2Y14-specific substrate, UDPglucose, inhibited the forskolin-induced cAMP production.3. Signaling studies show treatment of HLMVEC with UDP-glucose activates the Raf-1/MEK-1/ERK1/2 pathway. 4. The ECIS (Electrical cell-substrate impedance sensing) data indicate that pretreatment of HLMVEC with UDP-glucose (100μM,15min) stimulated wound healing suggesting the participation of P2Y14 in endothelial repair after acute lung injury.CONCLUSIONS1. P2Y14 receptor is widely expressed in stomach, placenta, adipose tissue, lung, heart and many kinds of immunocells. Our data indicate for the first time that P2Y14 is expressed in endothelial cells (HLMVEC). This result will benefit the other functional and expressional studies of P2Y14 receptor in many kinds of other cells and tissues.2. The cAMP assay indicates that P2Y14 is functional in HLMVEC as an addition of the P2Y14-specific substrate, UDPglucose, inhibited the forskolin-induced cAMP production. Therefore, tumor cell growth and differentiation may be regulated by P2Y14 receptor through the up- or down-regulation of cAMP in the cells.3. The treatment of HLMVEC with UDP-glucose activates the Raf-1/MEK-1/ERK1/2 pathway, and thus can promote the cells go from G0/G1 to S cycle and further affect the cell proliferation, differentiation and apoptosis and so on.4. The wound and function disorder of endothelial cells are close related many kinds of diseases. The pretreatment of HLMVEC with UDP-glucose stimulated wound healing suggesting the participation of P2Y14 in endothelial repair after acute injury.