Molecular Docking Studies of Methamphetamine and Amphetamine- Related Derivatives as an Inhibitor against Dopamine Receptor.

BACKGROUND: The catecholamines such as dopamine, norepinephrine, and epinephrine are neurotransmitters that regulate different physiological functions of the central nervous system. Some evidence suggests that the degeneration of dopamine neurons in the substantia nigra contributes to Parkinson's Disease (PD), which is a neurodegenerative disorder and it is responsible for the major symptoms of PD. It is suggested that replenishment of striatal dopamine through the oral administration of the dopamine precursor, levodopa, can compensate for the lack of endogenously produced dopamine. Some studies have shown competitive inhibition of dopamine receptor such as methamphetamine, and other amphetamine-related derivatives, which block dopamine receptor activity to uptake dopamine. METHODS: In this study, 3D structures of amphetamine, methamphetamine, cocaine, methylphenidate, cathinone, MDMA, and mephedrone were obtained from the PubChem database, which has reported some evidence about their inhibitory effect with dopamine receptor. Then, these structures were provided for molecular docking analysis by Autodock Vina software. Eventually, the binding energies between docked dopamine receptor and them were calculated and their interactions were prognosticated. RESULTS: Our results indicated that all chemicals can interact with dopamine receptor molecule in the active site of dopamine and the minimum binding energies belong to Cocaine and Methylphenidate with -7.9 Kcal/mol and -7.2 Kcal/mol, respectively. CONCLUSION: It might be concluded that amphetamine, methamphetamine, cocaine, methylphenidate, cathinone, MDMA, and mephedrone could act as potential inhibitors of DA receptor for dopamine uptake, which could cause degenerative disorders.

Apelin-13 Protects PC12 Cells Against Methamphetamine-Induced Oxidative Stress, Autophagy and Apoptosis.

Methamphetamine (METH) is a potent psychomotor stimulant that has a high potential for abuse in humans. In addition, it is neurotoxic, especially in dopaminergic neurons. Long-lasting exposure to METH causes psychosis and increases the risk of Parkinson's disease. Apelin-13 is a novel endogenous ligand which studies have shown that may have a neuroprotective effect. Therefore, we hypothesized that Apelin-13 might adequately prevent METH-induced neurotoxicity via the inhibition of apoptotic, autophagy, and ROS responses. In this study, PC12 cells were exposed to both METH (0.5, 1, 2, 3, 4, 6 mmol/L) and Apelin-13 (0.5, 1.0, 2.0, 4.0, 8.0 µmol/L) in vitro for 24 h to measure determined dose, and then downstream pathways were measured to investigate apoptosis, autophagy, and ROS responses. The results have indicated that Apelin-13 decreased the apoptotic response post-METH exposure in PC12 cells by increasing cell viability, reducing apoptotic rates. In addition, the study has revealed Apelin-13 decreased gene expression of Beclin-1 by Real-Time PCR and LC3-II by western blotting in METH-induced PC12 cells, which demonstrated autophagy is reduced. In addition, this study has shown that Apelin-13 reduces intracellular ROS of METH-induced PC12 cells. These results support Apelin-13 to be investigated as a potential drug for treatment of neurodegenerative diseases. It is suggested that Apelin-13 is beneficial in reducing oxidative stress, which may also play an important role in the regulation of METH-triggered apoptotic response. Hence, these data indicate that Apelin-13 could potentially alleviate METH-induced neurotoxicity via the reduction of oxidative damages, apoptotic, and autophagy cell death.

Nesfatin-1 protects PC12 cells against high glucose-induced cytotoxicity via inhibiting oxidative stress, autophagy and apoptosis.

OBJECTIVE: Diabetic neuropathy (DN) is the most common complication of diabetes mellitus. It is thought that neuronal cell death which is mainly due to reactive oxygen species (ROS) overproduction in the cells is responsible for most symptoms of this disorder. Nesfatin-1 has identified recently as a novel endogenous neuropeptide which recent studies have shown that it may have a protective effect. Therefore, we postulated that Nesfatin-1 might adequately prevent from high glucose-induced cell injury via inhibition of apoptotic, autophagy, and ROS responses. METHODS: In this study, PC12 cells were pretreated with different concentrations of Nesfatin-1 (1-100 ng/ml) and then co-treated with Nesfatin-1 and glucose (125 mM) for 48 h, and downstream pathways then were evaluated to investigate ROS, apoptosis, and autophagy. RESULTS: Results of this study showed that Nesfatin-1 can not only inhibit from intracellular ROS overproduction-induced by high glucose in PC12 cells (p < 0.0001) but also reduce the apoptotic cell death in PC12 cells following high glucose exposure by increasing cell viability and reducing apoptotic rates (p < 0.05). Furthermore, Nesfatin-1 decreased the LC3-II levels by western blotting (p < 0.0001), which showed a reduction in autophagy. CONCLUSION: These results support the idea that Nasfatin-1can protect PC12 cells against high glucose-induced cell injury by inhibition of apoptosis, autophagy and ROS production and can be considered as a potential drug for treatment of diabetic neuropathy.

Expression analysis of PD-1 and Tim-3 immune checkpoint receptors in patients with vitiligo; positive association with disease activity.

The contribution of immune checkpoint receptors in the immunopathogenesis of various autoimmune diseases has been addressed in previous reports. In this study,  the expression profile of T-cell immunoglobulin and mucin-domain containing-3 (Tim-3) and programmed cell death-1 (PD-1) checkpoint molecules was investigated in CD8+ T cells of Vitiligo patients. The association of Tim-3 and PD-1 expression with disease activity was also explored. The frequency of Tim-3+ /PD-1+ /CD8+ T cells in 30 patients with vitiligo and 30 sex- and age-matched controls was determined by flow cytometry. CD8+ T cells were then positively isolated by magnetic beads, and the mRNA expression of PD-1 and Tim-3 was determined by TaqMan-based real-time PCR. To measure the cytokines production, PBMCs were stimulated with PMA/ionomycin and concentrations of IL-4, IFN-γ and TNF-α were measured in culture supernatants by ELISA. Disease activity of patients with vitiligo was determined using the Vitiligo Area Severity Index. Patients with vitiligo have significantly shown more expression of Tim-3 and PD-1 on their CD8+ T cells compared with controls. Expression analysis of Tim-3 mRNA, but not PD-1, confirmed the results obtained from flow cytometry. While the production levels of TNF-α and IFN-γ were found higher by patients with vitiligo, IL-4 production was lower in patients compared with controls. A direct association was observed between the Tim-3 and PD-1 expression and also the production of pro-inflammatory cytokines with disease activity of patients with vitiligo. Our results indicate that Tim-3 and PD-1 are involved in immune dysregulation mechanisms of CD8+ T cells in vitiligo and may introduce as potential biomarkers for disease progression and targeted immunotherapy.