Methamphetamine regulates βAPP processing in human neuroblastoma cells

Association between CNS-active drugs and risk of Alzheimer's and age-related neurodegenerative diseases

Objective

As neuropsychiatric conditions can increase the risk of age-related neurodegenerative diseases (NDDs), the impact of CNS-active drugs on the risk of developing Alzheimer's Disease (AD), non-AD dementia, Multiple Sclerosis (MS), Parkinson's Disease (PD) and Amyotrophic Lateral Sclerosis (ALS) was investigated.

Research design and methods

A retrospective cohort analysis of a medical claims dataset over a 10 year span was conducted in patients aged 60 years or older. Participants were propensity score matched for comorbidity severity and demographic parameters. Relative risk (RR) ratios and 95% confidence intervals (CI) were determined for age-related NDDs. Cumulative hazard ratios and treatment duration were determined to assess the association between CNS-active drugs and NDDs at different ages and treatment duration intervals.

Results

In 309,128 patients who met inclusion criteria, exposure to CNS-active drugs was associated with a decreased risk of AD (0.86% vs 1.73%, RR: 0.50; 95% CI: 0.47-0.53; p <.0001) and all NDDs (3.13% vs 5.76%, RR: 0.54; 95% CI: 0.53-0.56; p <.0001). Analysis of impact of drug class on risk of AD indicated that antidepressant, sedative, anticonvulsant, and stimulant medications were associated with significantly reduced risk of AD whereas atypical antipsychotics were associated with increased AD risk. The greatest risk reduction for AD and NDDs occurred in patients aged 70 years or older with a protective effect only in patients with long-term therapy (>3 years). Furthermore, responders to these therapeutics were characterized by diagnosed obesity and higher prescriptions of anti-inflammatory drugs and menopausal hormonal therapy, compared to patients with a diagnosis of AD (non-responders). Addition of a second CNS-active drug was associated with greater reduction in AD risk compared to monotherapy, with the combination of a Z-drug and an SNRI associated with greatest AD risk reduction.

Conclusion

Collectively, these findings indicate that CNS-active drugs were associated with reduced risk of developing AD and other age-related NDDs. The exception was atypical antipsychotics, which increased risk. Potential use of combination therapy with atypical antipsychotics could mitigate the risk conferred by these drugs. Evidence from these analyses advance precision prevention strategies to reduce the risk of age-related NDDs in persons with neuropsychiatric disorders.

Key roles of autophagosome/endosome maturation mediated by Syntaxin17 in methamphetamine-induced neuronal damage in mice

BACKGROUND

Autophagic defects are involved in Methamphetamine (Meth)-induced neurotoxicity. Syntaxin 17 (Stx17), a member of the SNARE protein family, participating in several stages of autophagy, including autophagosome-late endosome/lysosome fusion. However, the role of Stx17 and potential mechanisms in autophagic defects induced by Meth remain poorly understood.

METHODS

To address the mechanism of Meth-induced cognitive impairment, the adenovirus (AV) and adeno-associated virus (AAV) were injected into the hippocampus for stereotaxis to overexpress Stx17 in vivo to examine the cognitive ability via morris water maze and novel object recognition. In molecular level, the synaptic injury and autophagic defects were evaluated. To address the Meth induced neuronal damage, the epidermal growth factor receptor (EGFR) degradation assay was performed to evaluate the degradability of the "cargos" mediated by Meth, and mechanistically, the maturation of the vesicles, including autophagosomes and endosomes, were validated by the Co-IP and the GTP-agarose affinity isolation assays.

RESULTS

Overexpression of Stx17 in the hippocampus markedly rescued the Meth-induced cognitive impairment and synaptic loss. For endosomes, Meth exposure upregulated Rab5 expression and its guanine-nucleotide exchange factor (GEF) (immature endosome), with a commensurate decreased active form of Rab7 (Rab7-GTP) and impeded the binding of Rab7 to CCZ1 (mature endosome); for autophagosomes, Meth treatment elicited a dramatic reduction in the overlap between Stx17 and autophagosomes but increased the colocalization of ATG5 and autophagosomes (immature autophagosomes). After Stx17 overexpression, the Rab7-GTP levels in purified late endosomes were substantially increased in parallel with the elevated mature autophagosomes, facilitating cargo (Aβ42, p-tau, and EGFR) degradation in the vesicles, which finally ameliorated Meth-induced synaptic loss and memory deficits in mice.

CONCLUSION

Stx17 decrease mediated by Meth contributes to vesicle fusion defects which may ascribe to the immature autophagosomes and endosomes, leading to autophagic dysfunction and finalizes neuronal damage and cognitive impairments. Therefore, targeting Stx17 may be a novel therapeutic strategy for Meth-induced neuronal injury.

Differential Gene Expression in the Hippocampi of Nonhuman Primates Chronically Exposed to Methamphetamine, Cocaine, or Heroin

OBJECTIVE

Methamphetamine (MA), cocaine, and heroin cause severe public health problems as well as impairments in neural plasticity and cognitive function in the hippocampus. This study aimed to identify the genes differentially expressed in the hippocampi of cynomolgus monkeys in response to these drugs.

METHODS

After the monkeys were chronically exposed to MA, cocaine, and heroin, we performed large-scale gene expression profiling of the hippocampus using RNA-Seq technology and functional annotation of genes differentially expressed. Some genes selected from RNA-Seq analysis data were validated with reverse transcription-quantitative polymerase chain reaction (RT-qPCR). And the expression changes of ADAM10 protein were assessed using immunohistochemistry.

RESULTS

The changes in genes related to axonal guidance (PTPRP and KAL1), the cell cycle (TLK2), and the regulation of potassium ions (DPP10) in the drug-treated groups compared to the control group were confirmed using RT-qPCR. Comparative analysis of all groups showed that among genes related to synaptic long-term potentiation, CREBBP and GRIN3A were downregulated in both the MA- and heroin-treated groups compared to the control group. In particular, the mRNA and protein expression levels of ADAM10 were decreased in the MA-treated group but increased in the cocaine-treated group compared to the control group.

CONCLUSION

These results provide insights into the genes that are upregulated and downregulated in the hippocampus by the chronic administration of MA, cocaine, or heroin and basic information for developing novel drugs for the treatment of hippocampal impairments caused by drug abuse.

Methamphetamine and Modulation Functionality of the Prelimbic Cortex for Developing a Possible Treatment of Alzheimer's Disease in an Animal Model

Alzheimer’s disease (AD) is a progressive neurodegenerative condition that causes cognitive impairment and other neuropsychiatric symptoms. Previously, little research has thus far investigated whether methamphetamine (MAMPH) can enhance cognitive function or ameliorate AD symptoms. This study examined whether a low dose of MAMPH can induce conditioned taste aversion (CTA) learning, or can increase plasma corticosterone levels, neural activity, and neural plasticity in the medial prefrontal cortex (mPFC) (responsible for cognitive function), the nucleus accumbens (NAc) and the amygdala (related to rewarding and aversive emotion), and the hippocampus (responsible for spatial learning). Furthermore, the excitations or lesions of the prelimbic cortex (PrL) can affect MAMPH-induced CTA learning, plasma corticosterone levels, and neural activity or plasticity in the mPFC [i.e., PrL, infralimbic cortex (IL), cingulate cortex 1 (Cg1)], the NAc, the amygdala [i.e., basolateral amygdala (BLA) and central amygdala (CeA)], and the hippocampus [i.e., CA1, CA2, CA3, and dentate gyrus (DG)]. In the experimental procedure, the rats were administered either saline or NMDA solutions, which were injected into the PrL to excite or destroy PrL neurons. Additionally, rats received 0.1% saccharin solution for 15 min, followed by intraperitoneal injections of either normal saline or 1 mg/kg MAMPH to induce CTA. A one-way ANOVA was performed to analyze the effects of saccharin intake on CTA, plasma corticosterone levels, and the expression of c-Fos and p-ERK. The results showed that the MAMPH induced CTA learning and increased plasma corticosterone levels. The mPFC, and particularly the PrL and IL and the DG of the hippocampus, appeared to show increased neural activity in c-Fos expression or neural plasticity in p-ERK expression. The excitation of the PrL neurons upregulated neural activity in c-Fos expression and neural plasticity in p-ERK expression in the PrL and IL. In summary, MAMPH may be able to improve cognitive and executive function in the brain and reduce AD symptoms. Moreover, the excitatory modulation of the PrL with MAMPH administration can facilitate MAMPH-induced neural activity and plasticity in the PrL and IL of the mPFC. The present data provide clinical implications for developing a possible treatment for AD in an animal model.

Alteration of gene expression in reactive astrocytes induced by Aβ1-42 using low dose of methamphetamine

BACKGROUND

Alzheimer's disease (AD) is a degenerative brain disorder. Due to the relationship between the functional loss of astrocytes and AD, the present study aims to evaluate the effects of the low dose of methamphetamine (METH) on primary fetal human astrocytes under a stress paradigm as a possible model for AD.

METHODS AND RESULTS

The groups in this study included Aβ (Group 1), METH (Group 2), Aβ + METH (METH after adding Aβ for 24 h) (Group 3 as treated group), METH + Aβ (Aβ after adding METH for 24 h) (Group 4 as prevention group), and control group. Then, the gene expression of Bax, Bcl-X, PKCα, GSK3β, and Cdk5 was evaluated. In addition, phosphorylated tau, p-GSK3β, GSK3β, and GSK3α proteins were assessed by western blotting. Further, cell cycle arrest and apoptosis were checked by flow cytometry and Hoechst staining. Based on the results, the expression of GSK3β, Cdk5, and PKCα genes decreased in the prevention group, while GSK3β and Cdk5 were amplified in the treatment group. Furthermore, the level of GSK3α and GSK3β proteins in the treatment group increased, while it decreased in the prevention group. Additionally, a decrease occurred in the percentage of necrosis and early apoptosis in the treatment and prevention groups. The results of the cell cycle indicated that G1 increased, while G2 decreased in the prevention group.

CONCLUSION

The pure form of METH can prevent from activating GSK-3β and CdK-5, as well as enhanced activity of PKCα to inhibit phosphorylated tau protein. Therefore, a low dose of METH may have a protective effect or reducing role in the pathway of tau production in reactive astrocytes.

Melatonin protects against methamphetamine-induced Alzheimer's disease-like pathological changes in rat hippocampus

Methamphetamine (METH) is a psychostimulant drug of abuse. METH use is associated with cognitive impairments and neurochemical abnormalities comparable to pathological changes observed in Alzheimer's disease (AD). These observations have stimulated the idea that METH abusers might be prone to develop AD-like signs and symptoms. Melatonin, the pineal hormone, is considered as a potential therapeutic intervention against AD. We thus conducted the present study to explore potential protective roles of melatonin against METH-induced deficits in learning and memory as well as in the appearance of AD-like pathological changes in METH-treated male Wistar rats. We found that melatonin ameliorated METH-induced cognitive impairments in those rats. Melatonin prevented METH-induced decrease in dopamine transporter (DAT) expression in rat hippocampus. Melatonin reversed METH-induced activation of β-arrestin2, reduction of phosphorylation of protein kinase B (Akt) and METH-induced excessive activity of glycogen synthase kinase-3β (GSK3β). Importantly, melatonin inhibited METH-induced changes in the expression of β-site APP cleaving enzyme (BACE1), disintegrin and metalloproteinase 10 (ADAM10), and presenilin 1 (PS1), as well as the reduction of amyloid beta (Aβ)42 production. Immunofluorescence double-labeling demonstrated that melatonin not only prevented the METH-induced loss of DAT but also prevented METH-induced Aβ42 overexpression in the dentate gyrus, CA1, and CA3. Furthermore, melatonin also suppressed METH-induced increase in phosphorylated tau. Significantly, melatonin attenuated METH-induced increase in N-methyl-D-aspartate receptor subtype 2 B (NR2B) protein expression and restored METH-induced reduction of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII). This suggested that melatonin attenuated the toxic effect of METH on the hippocampus involving the amyloidogenic pathway. Taken together, our data suggest that METH abuse may be a predisposing risk factor for AD and that melatonin could serve as a potential therapeutic agent to prevent METH-induced AD like pathology.

Cocaine-related DNA methylation in caudate neurons alters 3D chromatin structure of the IRXA gene cluster

Epigenetic mechanisms, like those involving DNA methylation, are thought to mediate the relationship between chronic cocaine dependence and molecular changes in addiction-related neurocircuitry, but have been understudied in human brain. We initially used reduced representation bisulfite sequencing (RRBS) to generate a methylome-wide profile of cocaine dependence in human post-mortem caudate tissue. We focused on the Iroquois Homeobox A (IRXA) gene cluster, where hypomethylation in exon 3 of IRX2 in neuronal nuclei was associated with cocaine dependence. We replicated this finding in an independent cohort and found similar results in the dorsal striatum from cocaine self-administering mice. Using epigenome editing and 3C assays, we demonstrated a causal relationship between methylation within the IRX2 gene body, CTCF protein binding, three-dimensional (3D) chromatin interaction, and gene expression. Together, these findings suggest that cocaine-related hypomethylation of IRX2 contributes to the development and maintenance of cocaine dependence through alterations in 3D chromatin structure in the caudate nucleus.

Pathological methamphetamine exposure triggers the accumulation of neuropathic protein amyloid-β by inhibiting UCHL1

Methamphetamine (METH), a powerful psychoactive drug, causes damage to the nervous system and leads to degenerative changes similar to Alzheimer's disease (AD), however, the molecular mechanism between the toxicity of METH and AD-related symptoms remains poorly understood. In this study, we investigated the effect of METH exposure on the accumulation of amyloid-β by establishing the animal and cell models. The results showed that METH exposure increased amyloid precursor protein (APP) and β-secretase (BACE1), contributed to the accumulation of amyloid-β, and which was alleviated with the pretreatment of BACE1 inhibitor. In addition, METH exposure decreased ubiquitin carboxy-terminal hydrolases L1 (UCHL1) which was related to the degradation of BACE1, and therefore led to the up-regulation of BACE1. In summary, the study could provide a new insight into the molecular mechanisms of METH toxicity and new evidence for the link between METH abuse and AD.

MicroRNA-181a Is Involved in Methamphetamine Addiction Through the ERAD Pathway

The regulation of microRNA (miRNA) is closely related to methamphetamine (METH) addiction. Past studies have reported that miR-181a is associated with METH addiction, but the mechanism pathways remain elusive. On the basis of our past studies, which reported the endoplasmic reticulum-associated protein degradation (ERAD) mediated ubiquitin protein degradation of GABAAα1, which was involved in METH addiction. The present study, using qRT-PCR and bioinformatics analysis, further revealed that miR-181a may be indirectly responsible for the METH addiction and downregulation of GABAAα1 through the regulation of ERAD.

Role of microRNAs in the pathophysiology of addiction

Addiction is a chronic and relapsing brain disorder characterized by compulsive seeking despite adverse consequences. There are both heritable and epigenetic mechanisms underlying drug addiction. Emerging evidence suggests that non-coding RNAs (ncRNAs) such as microRNAs (miRNAs), long non-coding RNAs, and circular RNAs regulate synaptic plasticity and related behaviors caused by substances of abuse. These ncRNAs modify gene expression and may contribute to the behavioral phenotypes of addiction. Among the ncRNAs, the most widely researched and impactful are miRNAs. The goal in this systematic review is to provide a detailed account of recent research involving the role of miRNAs in addiction. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Small Molecule-RNA Interactions RNA in Disease and Development > RNA in Disease.

Meta-Analysis of Methamphetamine Modulation on Amyloid Precursor Protein through HMGB1 in Alzheimer's Disease

The deposition of amyloid-beta (Aβ) through the cleavage of amyloid-beta precursor protein (APP) is a biomarker of Alzheimer’s disease (AD). This study used QIAGEN Ingenuity Pathway Analysis (IPA) to conduct meta-analysis on the molecular mechanisms by which methamphetamine (METH) impacts AD through modulating the expression of APP. All the molecules affected by METH and APP were collected from the QIAGEN Knowledge Base (QKB); 78 overlapping molecules were identified. Upon simulation of METH exposure using the “Molecule Activity Predictor” feature, eight molecules were found to be affected by METH and exhibited activation relationships on APP expression at a confidence of p = 0.000453 (Z-score = 3.51, two-tailed). Core Analysis of these eight molecules identified High Mobility Group Box protein 1 (HMGB1) signaling pathway among the top 5 canonical pathways with most overlap with the 8-molecule dataset. Simulated METH exposure increased APP expression through HMGB1 at a confidence of p < 0.00001 (Z-score = 7.64, two-tailed). HMGB1 is a pathogenic hallmark in AD progression. It not only increases the production of inflammatory mediators, but also mediates the disruption of the blood-brain barrier. Our analyses suggest the involvement of HMGB1 signaling pathway in METH-induced modulation of APP as a potential casual factor of AD.

Screening for Cognitive Dysfunction in Amphetamine Users in Saudi Arabia; a Case-control Investigation Using Propensity Score Matching Analysis

Amphetamine users have deficits in cognitive performance; however, the effects of duration and amount of use on cognitive decline remain elusive. The aim of this study was to evaluate the correlates of cognitive functioning in amphetamine users in Saudi Arabia. This was a case-control community-based study, using an Arabic adaptation of Addenbrooke's Cognitive Examination (ACE). The study compared users of amphetamine (n = 50) and controls (n = 50) in terms of performance on the ACE. Amphetamine users underperformed controls in the cognitive domains of attention, memory, language, fluency, and visuospatial faculties, even after controlling for psychiatric and sociodemographic variables. Heavy and prolonged use of amphetamine was associated with worse cognitive performance. Use of amphetamine at lower doses was not associated with worsening of cognitive functioning. The study adds to the evidence that amphetamine use is associated with impairment in cognitive functioning in Saudi Arabia. This has implications in terms of designing therapeutic interventions that account for potential cognitive difficulties in amphetamine abusers.

The multi-faceted impact of methamphetamine on Alzheimer's disease: From a triggering role to a possible therapeutic use

Although it has been initially synthesized for therapeutic purposes and currently FDA-approved and prescribed for obesity, attention-deficit/hyperactivity disorder, narcolepsy and depression, methamphetamine became a recreational drug that is nowadays massively manufactured illegally. Because it is a powerful and extremely addictive psychotropic agent, its abuse has turned out to become a major health problem worldwide. Importantly, the numerous effects triggered by this drug induce neurotoxicity in the brain ultimately leading to serious neurological impairments, tissue damage and neuropsychological disturbances that are reminiscent to most of the symptoms observed in Alzheimer's disease and other pathological manifestations in aging brain. In this context, there is a growing number of compelling evidence linking methamphetamine abuse with a higher probability of developing premature Alzheimer's disease and consequent neurodegeneration. This review proposes to establish a broad assessment of the effects that this drug can generate at the cellular and molecular levels in connection with the development of the age-related Alzheimer's disease. Altogether, the objective is to warn against the long-term effects that methamphetamine abuse may convey on young consumers and the increased risk of developing this devastating brain disorder at later stages of their lives, but also to discuss a more recently emerging concept suggesting a possible use of methamphetamine for treating this pathology under proper and strictly controlled conditions.

Effects of physical training on brain functional connectivity of methamphetamine dependencies as assessed using functional near-infrared spectroscopy

OBJECTIVE

This study aims to assess the effects of physical training based on the functional near-infrared spectroscopy (fNIRS) and heart rate signals.

METHODS

The oxygenated hemoglobin concentration (Delta [HbO₂]) signals were recorded from the left prefrontal cortex (LPFC), right prefrontal cortex (RPFC), left motor cortex (LMC) and right motor cortex (RMC) of 23 subjects with methamphetamine (METH) dependencies at resting, spinning training and strength training states. The wavelet phase coherence (WPCO) values were calculated in four frequency intervals: I, 0.6-2; II, 0.145-0.6; III, 0.052-0.145; and IV, 0.021-0.052 Hz. During the spinning training and strength training states, heart rate signals were recorded at 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 min, respectively.

RESULTS

After physical training, the brain regions of LPFC, RPFC and LMC showed different degrees of activation in the subjects with METH dependencies (p <  0.05). The WPCO values between the brain regions significantly altered after spinning training and strength training (p <  0.05) in frequency intervals I, II, III and IV.

CONCLUSIONS

The altered WPCO values indicated physical training could affect brain functional connectivity (FC) to a certain extent in the subjects with METH dependencies. These findings provide a method for the assessment of the effects of physical training in FC and will contribute to the development of drug rehabilitation methods in subjects with METH dependencies.