ABSTRACT
Title
Palmithoylethanolamide inhibits release of nerve growth factor by inflammation-activated mast cells via the GPR55 orphan receptor
Authors
M. Scollo, G. Cantarella and R. Bernardini
Department of Clinical and Molecular Biomedicine, Univ. of Catania, School of Medicine
95125 Catania, Italy
Department of Clinical and Molecular Biomedicine, Univ. of Catania, School of Medicine
95125 Catania, Italy
Abstract
Nerve growth factor (NGF) is a pleiotropic member of the neurotrophin family. Beside its neuronal effects, NGF plays a role in various processes, including angiogenesis. Mast cells release NGF and are among elements contributing to angiogenesis, a process regulated by arrays of factors, including the inhibitory cannabinoids. The possible inhibitory role of cannabinoids on mast cell-related NGF mitogenic effect on endothelial cells was then investigated. Human mastocytic cells HMC-1, challenged with PMA to yield degranulation of NGF, were preincubated with the cannabinoid PEA.
Then, conditioned media were added to HUVEC cultures. PMA-activated HMC-1 cells released substantial amounts of NGF, whereas PEA inhibited PMA-induced NGF release. HUVEC proliferation increased after treatment with media from activated HMC-1 cells, while was reduced with media from HMC-1 cells treated with PEA. To characterize receptors mediating such effects of PEA, RT-PCR and western blot analysis were performed on HMC-1 cells. None of the two cannabinoid CB1 and CB2 receptors was expressed by HMC-1 cells, which expressed the orphan receptor GPR55. Blockade of GPR55 by transfection of HMC-1 cells with a specific mRNAi, resulted in failure of NGF release. In addition, PEA inhibited NGF release in cells transfected with the positive form. Results indicate that NGF released from inflammatory mast cells may induce angiogenesis. Cannabinoids appear to attenuate proangiogenic effects of NGF. Finally, cannabinoids should be considered for antiangiogenic treatment in disorders characterized by prominent inflammation.
Then, conditioned media were added to HUVEC cultures. PMA-activated HMC-1 cells released substantial amounts of NGF, whereas PEA inhibited PMA-induced NGF release. HUVEC proliferation increased after treatment with media from activated HMC-1 cells, while was reduced with media from HMC-1 cells treated with PEA. To characterize receptors mediating such effects of PEA, RT-PCR and western blot analysis were performed on HMC-1 cells. None of the two cannabinoid CB1 and CB2 receptors was expressed by HMC-1 cells, which expressed the orphan receptor GPR55. Blockade of GPR55 by transfection of HMC-1 cells with a specific mRNAi, resulted in failure of NGF release. In addition, PEA inhibited NGF release in cells transfected with the positive form. Results indicate that NGF released from inflammatory mast cells may induce angiogenesis. Cannabinoids appear to attenuate proangiogenic effects of NGF. Finally, cannabinoids should be considered for antiangiogenic treatment in disorders characterized by prominent inflammation.