Association of CREB1 gene polymorphism with drug seeking behaviour in eastern Indian addicts

The molecular neurobiology and neuropathology of opioid use disorder

The number of people diagnosed with opioid use disorder has skyrocketed as a consequence of the opioid epidemic and the increased prescribing of opioid drugs for chronic pain relief. Opioid use disorder is characterized by loss of control of drug taking, continued drug use in the presence of adverse consequences, and repeated relapses to drug taking even after long periods of abstinence. Patients who suffer from opioid use disorder often present with cognitive deficits that are potentially secondary to structural brain abnormalities that vary according to the chemical composition of the abused opioid. This review details the neurobiological effects of oxycodone, morphine, heroin, methadone, and fentanyl on brain neurocircuitries by presenting the acute and chronic effects of these drugs on the human brain. In addition, we review results of neuroimaging in opioid use disorder patients and/or histological studies from brains of patients who had expired after acute intoxication following long-term use of these drugs. Moreover, we include relevant discussions of the neurobiological mechanisms involved in promoting abnormalities in the brains of opioid-exposed patients. Finally, we discuss how novel strategies could be used to provide pharmacological treatment against opioid use disorder.

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Brain abnormalities caused by opioid intoxication.

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Intoxication of opioids leads to defects in brain neurocircuitries.

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Insight into the molecular mechanisms associated with craving in heroin addicts.

Impact of genetic polymorphisms on opioid misuse: a scoping review

We conducted a scoping review on genetic polymorphisms associated with opioid intake-related adverse patient outcomes including behavioral, physiological and clinical outcomes. We searched for studies on Medline®, EMBASE®, CINAHL®, Psychinfo® and SNPedia® from January 2006 to January 2018. Our study identified 33 genes and 71 SNPs associated with opioid-intake related adverse patient outcomes: four studies showing associations of nine SNPs with clinical events (e.g., arrhythmia, length of stay and deaths); six studies showing associations of 13 SNPs with respiratory depression and 25 studies showing associations of 50 SNPs with opioid misuse behaviors. Available pharmacogenetic-tests covered polymorphisms associated with opioids metabolism and ignored polymorphisms associated with opioids transport, receptor-binding and signaling that were linked with respiratory depression and misuse behaviors.

Four single nucleotide polymorphisms in genes involved in neuronal signaling are associated with Opioid Use Disorder in West Virginia

Objective

Pilot study to assess utility in opioid use disorder (OUD) of a panel of single nucleotide polymorphisms in genes previously related to substance use disorder (SUD) and/or phenotypes that predispose individuals to OUD/SUD.

Design

Genetic association study.

Setting

West Virginia University's Chestnut Ridge Center Comprehensive Opioid Abuse Treatment (COAT) clinic for individuals diagnosed with OUD.

Patients

Sixty patients 18 years of age or older with OUD undergoing medication (buprenorphine/naloxone)-assisted treatment (MAT); all sixty patients recruited contributed samples for genetic analysis.

Outcome Measures

Minor allele frequencies for single nucleotide polymorphisms.

Results

Four of the fourteen single nucleotide polymorphisms examined were present at frequencies that are statistically significantly different than in a demographically-matched general population.

Conclusions

For the purposes of testing WV individuals via genetic means for predisposition to OUD, at least four single nucleotide polymorphisms in three genes are likely to have utility in predicting susceptibility. Additional studies with larger populations will need to be conducted to confirm these results before use in a clinical setting.

CREB1 functional polymorphisms modulating promoter transcriptional activity are associated with type 2 diabetes mellitus risk in Chinese population

The cAMP responsive element binding protein 1 (CREB1) is a ubiquitous transcription factor that contributes to the regulation of gluconeogenesis. The mechanisms of the CREB1 function remain largely unknown. In this study, we aimed to explore genetic variations in CREB1 promoter region and determine whether these loci affect transcriptional activity and risk on type 2 diabetes (T2D). Three polymorphisms were identified and designated as MU₁, MU₂ and MU₃, respectively. Genotypic distribution analysis revealed that MU₁ genotypes presented similar distribution between T2D and healthy controls (P > 0.05), while the MU₂ and MU₃ showed significant differences (P < 0.05). Haplotypic blocks of the three loci were constructed, and H1-TGA, H2-TTT and H3-ATT had higher frequencies in T2D patients than those in controls. Association studies revealed that the three loci significantly affected plasma glucose, glycated hemoglobin and insulin secretion. Disequilibrium analysis identified that the MU₂ and MU₃ variants were strongly linked in T2D (r² = 0.348, D' = 1.0). Further analysis indicated that MU₂ (TT vs GG, OR = 2.38, 95%CI = 1.19-4.77, P = 0.01) and MU₃ (AA vs TT, OR = 1.16, 95%CI = 1.19-4.77, P = 0.04) were significantly associated with T2D in dominant genotypes. Luciferase assay showed that T-A haplotype from the highly linked MU₂ and MU₃ exhibited maximal promoter activity, which was consistent with the correlation results. We concluded that the TT genotype of MU₂ and the AA genotype of MU₃ could be used as molecular markers for evaluating the risk on T2D.

Transcriptional Regulators as Targets for Alcohol Pharmacotherapies

Alcohol use disorder (AUD) is a chronic relapsing brain disease that currently afflicts over 15 million adults in the United States. Despite its prevalence, there are only three FDA-approved medications for AUD treatment, all of which show limited efficacy. Because of their ability to alter expression of a large number of genes, often with great cell-type and brain-region specificity, transcription factors and epigenetic modifiers serve as promising new targets for the development of AUD treatments aimed at the neural circuitry that underlies chronic alcohol abuse. In this chapter, we will discuss transcriptional regulators that can be targeted pharmacologically and have shown some efficacy in attenuating alcohol consumption when targeted. Specifically, the transcription factors cyclic AMP-responsive element binding protein (CREB), peroxisome proliferator-activated receptors (PPARs), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and glucocorticoid receptor (GR), as well as the epigenetic enzymes, the DNA methyltransferases (DNMTs) and histone deacetylases (HDACs), will be discussed.

Synaptic Plasticity and Signal Transduction Gene Polymorphisms and Vulnerability to Drug Addictions in Populations of European or African Ancestry

AIM

Drug addiction is characterized, in part, by deregulation of synaptic plasticity in circuits involved in reward, stress, cue learning, and memory. This study was designed to assess whether 185 variants in 32 genes central to synaptic plasticity and signal transduction contribute to vulnerability to develop heroin and/or cocaine addiction.

METHODS

Analyses were conducted in a sample of 1860 subjects divided according to ancestry (African and European) and drug of abuse (heroin or cocaine).

RESULTS

Eighteen SNPs in 11 genes (CDK5R1, EPHA4, EPHA6, FOSL2, MAPK3, MBP, MPDZ, NFKB1, NTRK2, NTSR1, and PRKCE) showed significant associations (P < 0.01), but the signals did not survive correction for multiple testing. SNP rs230530 in the NFKB1 gene, encoding the transcription regulator NF-kappa-B, was the only SNP indicated in both ancestry groups and both addictions. This SNP was previously identified in association with alcohol addiction. SNP rs3915568 in NTSR1, which encodes neurotensin receptor, and SNP rs1389752 in MPDZ, which encodes the multiple PDZ domain protein, were previously associated with heroin addiction or alcohol addiction, respectively.

CONCLUSIONS

The study supports the involvement of genetic variation in signal transduction pathways in heroin and cocaine addiction and provides preliminary evidence suggesting several new risk or protective loci that may be relevant for diagnosis and treatment success.