Effects of maternal separation and methamphetamine exposure on protein expression in the nucleus accumbens shell and core.
ABSTRACT Early life adversity has been suggested to predispose an individual to later drug abuse. The core and shell sub-regions of the nucleus accumbens are differentially affected by both stressors and methamphetamine. This study aimed to characterize and quantify methamphetamine-induced protein expression in the shell and core of the nucleus accumbens in animals exposed to maternal separation during early development. Isobaric tagging (iTRAQ) which enables simultaneous identification and quantification of peptides with tandem mass spectrometry (MS/MS) was used. We found that maternal separation altered more proteins involved in structure and redox regulation in the shell than in the core of the nucleus accumbens, and that maternal separation and methamphetamine had differential effects on signaling proteins in the shell and core. Compared to maternal separation or methamphetamine alone, the maternal separation/methamphetamine combination altered more proteins involved in energy metabolism, redox regulatory processes and neurotrophic proteins. Methamphetamine treatment of rats subjected to maternal separation caused a reduction of cytoskeletal proteins in the shell and altered cytoskeletal, signaling, energy metabolism and redox proteins in the core. Comparison of maternal separation/methamphetamine to methamphetamine alone resulted in decreased cytoskeletal proteins in both the shell and core and increased neurotrophic proteins in the core. This study confirms that both early life stress and methamphetamine differentially affect the shell and core of the nucleus accumbens and demonstrates that the combination of early life adversity and later methamphetamine use results in more proteins being affected in the nucleus accumbens than either treatment alone.
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ABSTRACT: Mice treated with the psychostimulant methamphetamine (MA) showed the appearance of intracellular inclusions in the nucleus of medium sized striatal neurones and cytoplasm of neurones of the substantia nigra pars compacta but not in the frontal cortex. All inclusions contained ubiquitin, the ubiquitin activating enzyme (E1), the ubiquitin protein ligase (E3-like, parkin), low and high molecular weight heat shock proteins (HSP 40 and HSP 70). Inclusions found in nigral neurones stained for alpha-synuclein, a proteic hallmark of Lewy bodies that are frequently observed in Parkinson's disease and other degenerative disorders. However, differing from classic Lewy bodies, MA-induced neuronal inclusions appeared as multilamellar bodies resembling autophagic granules. Methamphetamine reproduced this effect in cultured PC12 cells, which offered the advantage of a simple cellular model for the study of the molecular determinants of neuronal inclusions. PC12 inclusions, similar to those observed in nigral neurones, were exclusively localized in the cytoplasm and stained for alpha-synuclein. Time-dependent experiments showed that inclusions underwent a progressive fusion of the external membranes and developed an electrodense core. Inhibition of dopamine synthesis by alpha-methyl-p-tyrosine (alphaMpT), or administering the antioxidant S-apomorphine largely attenuated the formation of inclusions in PC12 cells exposed to MA. Inclusions were again observed when alphaMpT-treated cells were loaded with l-DOPA, which restored intracellular dopamine levels.Journal of Neurochemistry 02/2004; 88(1):114-23. · 3.97 Impact Factor
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ABSTRACT: The recent discovery that brain PGP 9.5 is a ubiquitin carboxyl-terminal hydrolase suggests that the role of this protein should be studied in relation to ubiquitinated cellular inclusions characteristic of several chronic human degenerative diseases. Formalin-fixed, paraffin-processed sections known to contain ubiquitin-protein conjugate immunoreactivity in cortical Lewy bodies, neurofibrillary tangles, Rosenthal fibres, Pick bodies, spinal inclusions in motor neurone disease, and Mallory's hyaline in alcoholic liver disease were immunostained to localize PGP 9.5. The majority of cortical Lewy bodies in diffuse Lewy body disease showed immunoreactivity for PGP 9.5. In Alzheimer's disease, only a minority of loosely arranged globose-type neurofibrillary tangles were immunostained together with a minority of neurites surrounding senile plaques. In cerebellar astrocytomas, the periphery of the majority of Rosenthal fibers was immunostained in addition to strong diffuse cytoplasmic immunostaining in some astrocytes lacking apparent Rosenthal fibers. In Pick's disease, there was no immunostaining of inclusions but there was intense immunostaining of swollen Pick cells. No spinal inclusions in motor neurone disease were stained; however, anterior horn neurones appear to show increased levels of PGP 9.5 compared with those from control cases. No immunostaining of hepatic Mallory's hyaline was demonstrable, which accords with suggestions that PGP 9.5 is a tissue-specific ubiquitin C-terminal hydrolase isoenzyme. The differential detection of a ubiquitin C-terminal hydrolase in different forms of ubiquitinated inclusion body in the nervous system may form the basis of a method for assessment of the staging of inclusion body biogenesis and give insight into the dynamics of inclusion body formation.(ABSTRACT TRUNCATED AT 250 WORDS)The Journal of Pathology 07/1990; 161(2):153-60. · 7.59 Impact Factor
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ABSTRACT: The proteins of the MARCKS (myristoylated alanine-rich C kinase substrate) family were first identified as prominent substrates of protein kinase C (PKC). Since then, these proteins have been implicated in the regulation of brain development and postnatal survival, cellular migration and adhesion, as well as endo-, exo- and phago-cytosis, and neurosecretion. The effector domain of MARCKS proteins is phosphorylated by PKC, binds to calmodulin and contributes to membrane binding. This multitude of mutually exclusive interactions allows cross-talk between the signal transduction pathways involving PKC and calmodulin. This review focuses on recent, mostly biophysical and biochemical results renewing interest in this protein family. MARCKS membrane binding is now understood at the molecular level. From a structural point of view, there is a consensus emerging that MARCKS proteins are "natively unfolded". Interestingly, domains similar to the effector domain have been discovered in other proteins. Furthermore, since the effector domain enhances the polymerization of actin in vitro, MARCKS proteins have been proposed to mediate regulation of the actin cytoskeleton. However, the recent observations that MARCKS might serve to sequester phosphatidylinositol 4,5-bisphosphate in the plasma membrane of unstimulated cells suggest an alternative model for the control of the actin cytoskeleton. While myristoylation is classically considered to be a co-translational, irreversible event, new reports on MARCKS proteins suggest a more dynamic picture of this protein modification. Finally, studies with mice lacking MARCKS proteins have investigated the functions of these proteins during embryonic development in the intact organism.Biochemical Journal 03/2002; 362(Pt 1):1-12. · 4.65 Impact Factor