Neuroadaptations in the dorsal hippocampus underlie cocaine seeking during prolonged abstinence.

Relapse vulnerability in substance use disorder is attributed to persistent cue-induced drug seeking that intensifies (or "incubates") during drug abstinence. Incubated cocaine seeking has been observed in both humans with cocaine use disorder and in preclinical relapse models. This persistent relapse vulnerability is mediated by neuroadaptations in brain regions involved in reward and motivation. The dorsal hippocampus (DH) is involved in context-induced reinstatement of cocaine seeking but the role of the DH in cocaine seeking during prolonged abstinence has not been investigated. Here we found that transforming growth factor-ß (TGF-ß) superfamily member activin A is increased in the DH on abstinence day (AD) 30 but not AD1 following extended-access cocaine self-administration compared to saline controls. Moreover, activin A does not affect cocaine seeking on AD1 but regulates cocaine seeking on AD30 in a bidirectional manner. Next, we found that activin A regulates phosphorylation of NMDA receptor (NMDAR) subunit GluN2B and that GluN2B-containing NMDARs also regulate expression of cocaine seeking on AD30. Activin A and GluN2B-containing NMDARs have both previously been implicated in hippocampal synaptic plasticity. Therefore, we examined synaptic strength in the DH during prolonged abstinence and observed an increase in moderate long-term potentiation (LTP) in cocaine-treated rats compared to saline controls. Lastly, we examined the role of DH projections to the lateral septum (LS), a brain region implicated in cocaine seeking and found that DH projections to the LS govern cocaine seeking on AD30. Taken together, this study demonstrates a role for the DH in relapse behavior following prolonged abstinence from cocaine self-administration.

A role for the endocannabinoid enzymes monoacylglycerol and diacylglycerol lipases in cue-induced cocaine craving following prolonged abstinence.

Following exposure to drugs of abuse, long-term neuroadaptations underlie persistent risk to relapse. Endocannabinoid signaling has been associated with drug-induced neuroadaptations, but the role of lipases that mediate endocannabinoid biosynthesis and metabolism in regulating relapse behaviors following prolonged periods of drug abstinence has not been examined. Here, we investigated how pharmacological manipulation of lipases involved in regulating the expression of the endocannabinoid 2-AG in the nucleus accumbens (NAc) influence cocaine relapse via discrete neuroadaptations. At prolonged abstinence (30 days) from cocaine self-administration, there is an increase in the NAc levels of diacylglycerol lipase (DAGL), the enzyme responsible for the synthesis of the endocannabinoid 2-AG, along with decreased levels of monoacylglycerol lipase (MAGL), which hydrolyzes 2-AG. Since endocannabinoid-mediated behavioral plasticity involves phosphatase dysregulation, we examined the phosphatase calcineurin after 30 days of abstinence and found decreased expression in the NAc, which we demonstrate is regulated through the transcription factor EGR1. Intra-NAc pharmacological manipulation of DAGL and MAGL with inhibitors DO-34 and URB-602, respectively, bidirectionally regulated cue-induced cocaine seeking and altered the phosphostatus of translational initiation factor, eIF2α. Finally, we found that cocaine seeking 30 days after abstinence leads to decreased phosphorylation of eIF2α and reduced expression of its downstream target NPAS4, a protein involved in experience-dependent neuronal plasticity. Together, our findings demonstrate that lipases that regulate 2-AG expression influence transcriptional and translational changes in the NAc related to drug relapse vulnerability.

A Novel Role for the Histone Demethylase JMJD3 in Mediating Heroin-induced Relapse-Like Behaviors.

BACKGROUND: Epigenetic changes, leading to long-term neuroadaptations following opioid exposure are not well understood. We examined how histone demethylase JMJD3 in the nucleus accumbens (NAc) influences heroin seeking after abstinence from self-administration. METHODS: Male Sprague-Dawley rats were trained to self-administer heroin. Western blotting and qPCR were performed to quantify JMJD3 and bone morphogenetic protein (BMP) pathway expression in the NAc (n = 7-11/group). Pharmacological inhibitors or viral expression vectors were microinfused into the NAc to manipulate JMJD3 or the BMP pathway member SMAD1 (n = 9-11/group). The RiboTag capture method (n = 3-5/group) and viral vectors (n = 7-8/group) were used in male transgenic rats to identify the contributions of D1- and D2-type medium spiny neurons (MSN) in the NAc. Drug-seeking was tested by cue-induced response previously paired with drug infusion. RESULTS: Levels of JMJD3 and phosphorylated SMAD1/5 in the NAc were increased after 14 days of abstinence from heroin self-administration. Pharmacological and virus-mediated inhibition of JMJD3 or the BMP pathway attenuated cue-induced seeking. Pharmacological inhibition of BMP signaling reduced JMJD3 expression and histone 3 lysine 27 trimethylation (H3K27me3) levels. JMJD3 bidirectionally affected seeking: expression of the wild type increased whereas expression of a catalytic dead mutant decreased cue-induced seeking. JMJD3 expression was increased in D2+ but not D1+ MSNs. Expression of the mutant JMJD3 in D2+ neurons was sufficient to decrease cue-induced heroin seeking. CONCLUSIONS: JMJD3 mediates persistent cellular and behavioral adaptations underlying heroin relapse and this activity is regulated by the BMP pathway.

Protocatechuic acid inhibits rat pheochromocytoma cell damage induced by a dopaminergic neurotoxin.

Parkinson's disease (PD) is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra (SN) with the presence of alpha-synuclein inclusions termed Lewy bodies. The aggregation of alpha-synuclein into oligomeric species affects neuronal viability, having a causal role in the development of PD. The neuroprotective effects of protocatechuic acid (PAc) have been reported. However, the effects of PAc on tyrosine hydroxylase (TH) and alpha-synuclein in rat pheochromocytoma (PC12) cells treated with 1-methyl-4-phenylpyridinium ion (MPP(+)) remains unclear. In this study, we demonstrated that PAc inhibited the cytotoxicity, apoptotic morphology, reduction of TH expression and abnormal oligomeration of alpha-synuclein in PC12 cells treated with MPP(+). Taken together, our results indicate that the neuroprotective effects of PAc on PC12 cells treated with MPP(+) is related to the inhibition of the oligomerization of alpha-synuclein.

Cistanche extracts ameliorates the neurotoxicity induced by hydrogen peroxide in new mutant DJ-1-transfected neuroblastoma cellular models.

INTRODUCTION: DJ-1 mutation is a causative reason for familial Parkinson's disease (PD). Leucine166Proline (L166P) and C106S are two important DJ-1 mutations. In this study, we established hydrogen peroxide (H2 O2 ) induced L166P and C106S DJ-1-transfected neuroblastoma (SH-SY5Y) cellular models of PD and investigated the effects of Cistanche extracts and key bioactive compounds, including acteoside, echinacoside, caffeic acid, and Cistanche total glycosides on these two models. METHODS: After expressing FLAG-tagged L166P and C106S DJ-1 plasmids in Escherichia coli, the expressed plasmids were collected, treated with restriction enzyme, and identified using DNA electrophoresis. After purification, the L166P DJ-1 and C106S DJ-1 plasmids were separately transfected into SH-SY5Y cells using liposomes. Transfected SH-SY5Y cells were detected by western blotting and immunocytochemistry. Cell viability was determined using MTT assay. RESULTS: Both western blotting and immunocytochemistry showed that L166P and C106S DJ-1 were highly expressed in the transfected SH-SY5Y cells. MTT assays showed that transfection with L166P or C106S DJ-1 reduced the viability of SH-SY5Y cells exposed to H2 O2 , as compared to untransfected SH-SY5Y cells. In addition, Cistanche extracts and key bioactive compounds, including acteoside, echinacoside, caffeic acid, and Cistanche total glycosides, significantly inhibited the decreases of cell viability caused by H2 O2 in L166P and C106S DJ-1-transfected SH-SY5Y cells. CONCLUSIONS: These findings suggest that we successfully established sensitive and stable H2 O2 induced L166P DJ-1- and C106S DJ-1-transfected SH-SY5Y cell models of PD and Cistanche extracts may thus be useful for treating PD.

Expression of the DJ-1 protein in the serum of Chinese patients with Parkinson's disease.

DJ-1 is one of the important genes found in Parkinson's disease (PD). Studies have shown that the DJ-1 protein levels are elevated in the cerebrospinal fluid (CSF) and plasma of sporadic PD patients, and the DJ-1 protein levels in the CSF and plasma may serve as biomarkers of PD. However, Japanese scholars previously reported that there was no difference in the levels of the DJ-1 protein in serum between sporadic PD patients and controls. Therefore, whether the serum DJ-1 protein levels are different between PD patients and controls in Chinese patients as well as whether serum DJ-1 protein can serve as a biomarker of PD are unknown. The present study aimed to determine whether there was a difference in serum DJ-1 protein levels between Chinese PD patients and controls. The subjects included 18 primary PD patients and 7 controls. Blood was collected by venipuncture, and serum was collected by centrifugation after the blood was coagulated. The serum DJ-1 protein levels were detected by both Western blot and ELISA. There were differences in the serum DJ-1 protein levels among different individuals. The serum DJ-1 concentration in PD patients was 11.3±10.1ng/ml, and that in controls was 18.1±12.8ng/ml (P>0.05). In conclusion, similar to the study conducted by Japanese scholars, we found no significant difference in the serum DJ-1 protein levels between PD patients and controls in Chinese subjects. The levels of the DJ-1 protein in serum may not be a biomarker of PD. In addition, there may be differences in the serum DJ-1 protein levels between Chinese and Japanese patients.

Correction: Se2Mo10V3, a heteropoly compound containing selenium, inhibits tumor growth.

[This corrects the article DOI: 10.18632/oncotarget.18909.].

Se2Mo10V3, a heteropoly compound containing selenium, inhibits tumor growth.

Selenium compounds have strong anti-tumor effects and are well-tolerated. We examined the anti-tumor effects of (NH4)2H15Se2VIMo10V3O52·2H2O (Se2Mo10V3), a heteropoly compound containing selenium. Se2Mo10V3 inhibited proliferation in K562 cells with a half-maximal inhibitory concentration of 78.72±2.82 mg/L after 48 h and 24.94±0.88 mg/L after 72 h. Typical apoptotic morphologies were also observed in K562 cells treated with Se2Mo10V3, as were increased intracellular levels of Ca2+, Mg2+, H+, and reactive oxygen species, and decreased mitochondrial membrane potential. In addition, Se2Mo10V3 treatment triggered cytochrome C release and inhibited IκBα degradation and NF-κB translocation. In vivo experiments revealed that 5 or 10 mg/kg Se2Mo10V3 inhibited the growth of sarcoma 180 and hepatoma 22 xenograft tumors. These results indicate that Se2Mo10V3 inhibits tumor growth both in vitro and in vivo and induces apoptosis in K562 cells, possibly by inhibiting the NF-κB/IκBα pathway.

DJ-1 protein protects dopaminergic neurons against 6-OHDA/MG-132-induced neurotoxicity in rats.

Parkinson disease (PD) is the second most common neurodegenerative disease, and it cannot be completely cured by current medications. In this study, DJ-1 protein was administrated into medial forebrain bundle of PD model rats those had been microinjected with 6-hydroxydopamine (6-OHDA) or MG-132. We found that DJ-1 protein could reduce apomorphine-induced rotations, inhibit reduction of dopamine contents and tyrosine hydroxylase levels in the striatum, and decrease dopaminergic neuron death in the substantia nigra. In 6-OHDA lesioned rats, uncoupling protein-4, uncoupling protein-5 and superoxide dismutase-2 (SOD2) mRNA and SOD2 protein were increased when DJ-1 protein was co-injected. Simultaneously, administration of DJ-1 protein reduced α-synuclein and hypoxia-inducible factor 1α mRNA and α-synuclein protein in MG-132 lesioned rats. Therefore, DJ-1 protein protected dopaminergic neurons in two PD model rats by increasing antioxidant capacity and inhibiting α-synuclein expression.

Down-regulation of DJ-1 protein in the ejaculated spermatozoa from Chinese asthenozoospermia patients.

OBJECTIVE: To determine whether the expression of DJ-1 protein, whose levels in spermatozoa have been reported to be highly correlated with male infertility caused by toxicants, is changed in spermatozoa of Chinese asthenozoospermia patients. DESIGN: DJ-1 measurement by Western blotting, quantitive ELISA, and isoelectric-focusing electrophoresis (IFE) combined with immunoblotting. SETTING: Academic medical center and research laboratories. PATIENT(S): Asthenozoospermia patients (n = 113), including mild asthenozoospermia patients (n = 70) and moderate asthenozoospermia patients (n = 43), and age-matched control subjects (n = 58). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): DJ-1 in spermatozoa was determined by Western blotting and ELISA, the isoelectric point (pI) of DJ-1 by IFE combined with immunoblotting, and sperm superoxide dismutase (SOD) activity by an assay kit. RESULT(S): The sperm DJ-1 concentration in moderate asthenozoospermia patients was lower than those in mild asthenozoospermia patients and control subjects. DJ-1 with a more acidic pI was increased in asthenozoospermia patients. Sperm SOD activity was decreased in asthenozoospermia patients. CONCLUSION(S): DJ-1 levels are reduced in moderate asthenozoospermia patients. DJ-1 concentration is positively correlated with sperm motility and sperm SOD activity indicated by partial correlation analysis.

Protocatechuic acid inhibits neurotoxicity induced by MPTP in vivo.

Parkinson's disease (PD) is characterized by the progressive degeneration of dopaminergic neurons in substantia nigra (SN) with the presence of alpha-synuclein inclusions termed Lewy bodies. The neuroprotective effects of protocatechuic acid (PAc) both in vitro and in vivo have been reported. However, little is known about the effects of PAc on neurotoxicity induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in vivo. In this study, we demonstrated that PAc inhibited the reduction of the latent periods in a rotarod test, and the contents of dopamine (DA) and its metabolites in striatum, and furthermore, it ameliorated the pathology in SN and the decreases in the expression of tyrosine hydroxylase (TH) in SN of C57BL/6J mice induced by MPTP. Taken together, our results indicate for the first time that PAc has neuroprotective effects on MPTP treated C57BL/6J mice and may be useful in clinical treatment of PD.