Hai-Yu Yang1, Xiao-Ping Pu2, Yong Liu3. 1. Institute of Clinical Medicial Sciences, Jiangxi Province People's Hospital, Nanchang 330006, P. R. China; Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Science, Peking University, Beijing 100191, P. R. China. Electronic address: yanghaiyu@yahoo.com. 2. Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Science, Peking University, Beijing 100191, P. R. China. 3. Department of Pathology, Jiangxi Province People's Hospital, Nanchang 330006, P. R. China.
Abstract
BACKGROUND: It has been shown that opioid dependence-related neuronal plasticity may rely not only on protein synthesis, but also on protein degradation, mainly mediated by ubiquitin-proteasome system (UPS). The aim of the present study was to determine the effect of morphine on the regulation of protein degradation in the brain and to determine which proteins are involved in the underlying mechanism. METHODS: Mice were given chronic morphine administration and the state of morphine dependence was confirmed by induction of naloxone-precipitated withdrawal jumping. The level of ubiquitinated proteins in the striatum and spinal cord of morphine-dependent mice was detected by Western blotting. One of the abnormal-ubiquitinated proteins in mice striatum was identified by electrospray ionization quadrupole time-of-flight tandem mass spectrometry and the result was further confirmed by Western blotting and immunofluorescence method. RESULTS: We found that the expression of some ubiquitinated proteins was clearly decreased in the striatum of morphine-depnendent mice, but not in the spinal cord. And we identified a ubiquitinated protein (>79 kDa) decreased in the striatum as heat shock cognate 70 protein, one member of the 70 kDa family of heat shock proteins (HSP70). Moreover, we confirmed the level of HSP70 protein was significantly increased in mice striatum. CONCLUSIONS: These data strongly suggest morphine-induced HSP70 overexpression in the striatum is closely related with its abnormal degradation by UPS and it seems to be an important mechanism associated with morphine dependence.
BACKGROUND: It has been shown that opioid dependence-related neuronal plasticity may rely not only on protein synthesis, but also on protein degradation, mainly mediated by ubiquitin-proteasome system (UPS). The aim of the present study was to determine the effect of morphine on the regulation of protein degradation in the brain and to determine which proteins are involved in the underlying mechanism. METHODS:Mice were given chronic morphine administration and the state of morphine dependence was confirmed by induction of naloxone-precipitated withdrawal jumping. The level of ubiquitinated proteins in the striatum and spinal cord of morphine-dependent mice was detected by Western blotting. One of the abnormal-ubiquitinated proteins in mice striatum was identified by electrospray ionization quadrupole time-of-flight tandem mass spectrometry and the result was further confirmed by Western blotting and immunofluorescence method. RESULTS: We found that the expression of some ubiquitinated proteins was clearly decreased in the striatum of morphine-depnendent mice, but not in the spinal cord. And we identified a ubiquitinated protein (>79 kDa) decreased in the striatum as heat shock cognate 70 protein, one member of the 70 kDa family of heat shock proteins (HSP70). Moreover, we confirmed the level of HSP70 protein was significantly increased in mice striatum. CONCLUSIONS: These data strongly suggest morphine-induced HSP70 overexpression in the striatum is closely related with its abnormal degradation by UPS and it seems to be an important mechanism associated with morphine dependence.
Authors: Emilia M Lefevre; Marc T Pisansky; Carlee Toddes; Federico Baruffaldi; Marco Pravetoni; Lin Tian; Thomas J Y Kono; Patrick E Rothwell Journal: Neuropsychopharmacology Date: 2020-02-20 Impact factor: 7.853