Yan Wang1,2, Yan-Hui Ge1, Yan-Xia Wang1, Ting Liu1, Ping-Yee Law3, Horace H Loh3, Hong-Zhuan Chen1, Yu Qiu1. 1. Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China. 2. Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA. 3. Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA.
Abstract
AIMS: Mechanistic/mammalian target of rapamycin (mTOR) activation by μ-opioid receptor (OPRM1) participates in antinociceptive tolerance, hyperalgesia, and physical dependence. Our previous study also showed that mTOR activation by OPRM1 could attenuate β amyloid oligomers-induced neurotoxicity. OPRM1 is demonstrated to interact with FK506-binding protein 12 (FKBP12). It is our great interest to investigate whether OPRM1-mediated mTOR signaling is related to receptor-FKBP12 association. METHODS: The activities of mTOR and its downstream effector p70 S6K were measured by immunoblotting their phosphorylation status. The interaction of receptor with mTOR was detected by co-immunoprecipitation and immunofluorescence. RESULTS: OPRM1 activation by morphine-induced time-dependent mTOR activation. PI3K-specific inhibitor LY294002 only blocked the late phase of mTOR activation. However, morphine-induced mTOR activation was totally blocked at all time points in cells expressing FKBP12 association-deficient mutant receptor. FKBP12 knockdown also blocked morphine-induced mTOR activation. Further analysis demonstrated that morphine treatment enhanced the association of receptor with phosphorylated mTOR, whereas decreased association was observed after FKBP12 knockdown, mTOR inhibition or in cells expressing FKBP12 association-deficient mutant. CONCLUSIONS: OPRM1-FKBP12 association played a key role in OPRM1-mediated mTOR activation, which could underlie the mechanisms of multiple physiological and pathological processes. Thus, our findings provide new avenue to modulating these processes.
AIMS: Mechanistic/mammalian target of rapamycin (mTOR) activation by μ-opioid receptor (OPRM1) participates in antinociceptive tolerance, hyperalgesia, and physical dependence. Our previous study also showed that mTOR activation by OPRM1 could attenuate β amyloid oligomers-induced neurotoxicity. OPRM1 is demonstrated to interact with FK506-binding protein 12 (FKBP12). It is our great interest to investigate whether OPRM1-mediated mTOR signaling is related to receptor-FKBP12 association. METHODS: The activities of mTOR and its downstream effector p70 S6K were measured by immunoblotting their phosphorylation status. The interaction of receptor with mTOR was detected by co-immunoprecipitation and immunofluorescence. RESULTS:OPRM1 activation by morphine-induced time-dependent mTOR activation. PI3K-specific inhibitor LY294002 only blocked the late phase of mTOR activation. However, morphine-induced mTOR activation was totally blocked at all time points in cells expressing FKBP12 association-deficient mutant receptor. FKBP12 knockdown also blocked morphine-induced mTOR activation. Further analysis demonstrated that morphine treatment enhanced the association of receptor with phosphorylated mTOR, whereas decreased association was observed after FKBP12 knockdown, mTOR inhibition or in cells expressing FKBP12 association-deficient mutant. CONCLUSIONS:OPRM1-FKBP12 association played a key role in OPRM1-mediated mTOR activation, which could underlie the mechanisms of multiple physiological and pathological processes. Thus, our findings provide new avenue to modulating these processes.
Authors: Arturo Giordano; Simona Romano; Maria Mallardo; Anna D'Angelillo; Gaetano Calì; Nicola Corcione; Paolo Ferraro; Maria Fiammetta Romano Journal: Cardiovasc Res Date: 2008-03-18 Impact factor: 10.787
Authors: Charles A Hoeffer; Wei Tang; Helen Wong; Arturo Santillan; Richard J Patterson; Luis A Martinez; Maria V Tejada-Simon; Richard Paylor; Susan L Hamilton; Eric Klann Journal: Neuron Date: 2008-12-10 Impact factor: 17.173