Selective DRD2 Antagonist and ClpP Agonist ONC201 in a Recurrent Non-midline H3 K27M-mutant Glioma Cohort

BACKGROUND

Diffuse midline glioma, H3 K27-altered (H3 K27M-altered DMG) are invariably lethal, disproportionately affecting the young and without effective treatment besides radiotherapy. The 2016 WHO CNS Tumors Classification defined H3K27M mutations as pathognomonic but restricted diagnosis to diffuse gliomas involving midline structures by 2018. Dordaviprone (ONC201) is an oral investigational small molecule, DRD2 antagonist and ClpP agonist associated with durable responses in recurrent H3K27M-mutant DMG. Activity of ONC201 in non-midline H3K27M-mutant diffuse gliomas has not been reported.

METHODS

Patients with recurrent non-midline H3K27M-mutant diffuse gliomas treated with ONC201 were enrolled on 5 trials. Eligibility included measurable disease by Response Assessment in Neuro-Oncology (RANO) high-grade glioma (HGG), Karnofsky/Lansky performance score (KPS/LPS) ≥60, and ≥90 days from radiation. The primary endpoint was overall response rate (ORR).

RESULTS

Five patients with cerebral gliomas (3 frontal, 1 temporal, and 1 parietal) met inclusion. One complete and one partial response were reported by investigators. Blinded independent central review confirmed ORR by RANO criteria for two, however one deemed nonmeasurable and another stable. A responding patient also noted improved mobility and alertness.

CONCLUSIONS

H3K27M-mutant diffuse gliomas occasionally occur in nonmidline cerebrum. ONC201 exhibits activity in H3K27M-mutant gliomas irrespective of CNS location.

Analysis of Dopamine Receptor D2 Gene Polymorphism and Correlation with Dyslipidemia in the Chinese Population

Objective

The study aimed to explore the genotype and allele distributions of dopamine D2-like receptor (DRD2) gene -141C and C957T polymorphisms in the Chinese Han population with dyslipidemia, as well as their association with serum lipid levels.

Methods

One hundred fifty patients with dyslipidemia and 150 healthy people were recruited as the case and the control groups, respectively. Serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol levels were detected. The target sequence of DRD2 polymorphisms was amplified by polymerase chain reaction and genotyped via Sanger sequencing.

Results

In DRD2 gene C957T (rs6277), three genotypes of CC, CT, and TT were detected with the frequencies of 92.67%, 6.67%, 0.67% in dyslipidemia cases, and 83.33%, 14.67%, 2.00% in the controls, respectively. The CT genotype and T allele frequencies were significantly low in the case group relative to the control group. After adjusting to other clinical indicators, the CT genotype of C957T polymorphism (hazard ratio = 0.401, 95% confidence interval = 0.181-0.890, p < 0.05) was still related to a significantly reduced risk of dyslipidemia. The C957T CT genotype carriers had the lowest values of serum TC, TG, LDL, and the highest values of serum HDL-C.

Conclusion

DRD2 gene C957T polymorphism was an independent influencing factor associated with the susceptibility to dyslipidemia, and the CT genotype was associated with decreased odds of susceptibility to dyslipidemia.

Activation of the Hippocampal DRD2 Alleviates Neuroinflammation, Synaptic Plasticity Damage and Cognitive Impairment After Sleep Deprivation

Sleep loss is commonplace nowadays and profoundly impacts cognition. Dopamine receptor D2 (DRD2) makes a specific contribution to cognition, although the precise mechanism underlying how DRD2 affects the cognitive process after sleep deprivation remains unclear. Herein, we observed cognitive impairment and impaired synaptic plasticity, including downregulation of synaptophysin and PSD95, decreased postsynaptic density thickness, neuron complexity, and spine density in chronic sleep restriction (CSR) mice. We also observed downregulated hippocampal DRD2 and Cryab expression in the CSR mice. Meanwhile, NF-κB translocation from the cytoplasm to the nucleus occurred, indicating that neuroinflammation ensued. However, hippocampal delivery of the DRD2 agonist quinpirole effectively rescued these changes. In vitro, quinpirole treatment significantly decreased the release of proinflammatory cytokines in microglial supernatant, indicating a potential anti-neuroinflammatory effect of Drd2/Cryab/NF-κB in CSR mice. Our study provided the evidence that activation of the Drd2 may relieve neuroinflammation and improve sleep deprivation-induced cognitive deficits.

The molecular architecture of a complex social behavior: gregarious song

The medial preoptic area (mPOA) regulates the probability and intensity of singing behavior in birds. Polzin and colleagues examined the molecular changes in the mPOA that were associated with gregarious song in European starlings (Sturnus vulgaris). High-throughput transcriptome analyses identified glutamate and dopamine pathways were highly enriched with gregarious song.

Association of DRD2, DRD4 and COMT genes variants and their gene-gene interactions with antipsychotic treatment response in patients with schizophrenia

Antipsychotic drugs are the first line of treatment in schizophrenia; although antipsychotic responses indicate a wide interindividual variety in patients with schizophrenia. This study aimed to investigate the association between four polymorphisms in DRD2, DRD4 and COMT genes and their gene-gene interactions with antipsychotic treatment response in patients with schizophrenia. A total of 101 patients with schizophrenia were recruited and stratified in treatment responder and treatment resistant groups based on the published criteria of resistant to treatment using PANSS. Clinical and demographic factors were analyzed. Genomic DNA was extracted from whole blood and genotyping for the four polymorphisms were done by ARMS-PCR, PCR-RFLP and gap-PCR. Gene-gene interactions were analyzed by logistic regression. In case of DRD2 A-241G, G allele was significantly associated with resistant to treatment. Regarding DRD4 120-bp duplication, 240/240 genotype was significantly associated with resistant to treatment comparing to other genotypes in a dominant model. The genotype combination of DRD4 240/240 and COMT Val/Val was significantly associated with treatment resistant. Among DRD2 AA genotype, COMT met allele carriers which also had a 120 bp allele of DRD4 had a significantly better response to antipsychotics. Moreover, analysis of clinical and demographic factors demonstrated a significantly longer duration of hospitalization and higher chlorpromazine-equivalent daily dose in resistant to treatment patients. Discovering the polymorphisms which effect treatment response to antipsychotics will provide the possibility of genetic screening before starting an antipsychotic treatment which enhances the chance of responding to antipsychotics and decreases drugs side effects and costs.

Dopaminergic Input Regulates the Sensitivity of Indirect Pathway Striatal Spiny Neurons to Brain-Derived Neurotrophic Factor

Motor dysfunction in Parkinson's disease (PD) is closely linked to the dopaminergic depletion of striatal neurons and altered synaptic plasticity at corticostriatal synapses. Dopamine receptor D1 (DRD1) stimulation is a crucial step in the formation of long-term potentiation (LTP), whereas dopamine receptor D2 (DRD2) stimulation is needed for the formation of long-term depression (LTD) in striatal spiny projection neurons (SPNs). Tropomyosin receptor kinase B (TrkB) and its ligand brain-derived neurotrophic factor (BDNF) are centrally involved in plasticity regulation at the corticostriatal synapses. DRD1 activation enhances TrkB's sensitivity for BDNF in direct pathway spiny projection neurons (dSPNs). In this study, we showed that the activation of DRD2 in cultured striatal indirect pathway spiny projection neurons (iSPNs) and cholinergic interneurons causes the retraction of TrkB from the plasma membrane. This provides an explanation for the opposing synaptic plasticity changes observed upon DRD1 or DRD2 stimulation. In addition, TrkB was found within intracellular structures in dSPNs and iSPNs from Pitx3-/- mice, a genetic model of PD with early onset dopaminergic depletion in the dorsolateral striatum (DLS). This dysregulated BDNF/TrkB signaling might contribute to the pathophysiology of direct and indirect pathway striatal projection neurons in PD.

Polydopamine-loaded prunetin nanomaterials activate DRD2 to reduce UV-induced inflammation by stabilizing and promoting Nrf2 nuclear translocation

Skin damage caused by exposure to ultraviolet (UV) light has been well documented clinically and histologically. Dopamine receptor D2 (DRD2) possesses various biological functions. However, no study has reported the possible association of DRD2 with UV-induced skin damage. We established DRD2 conditional knockout and UV damage models in this work. The results showed that DRD2 played an important role in the treatment of UV-induced skin damage. The findings of the molecular mechanism study revealed that the internalization of DRD2 after activation can stabilize nuclear factor erythroid 2-related factor 2 (Nrf2). However, the entry of Nrf2 into the nucleus did not increase. We prepared and characterized hyaluronic acid (HA)-coated mesoporous polydopamine (MPDA) nanoparticles (H@P@M). HA facilitated skin epidermal penetration of the nanoparticles to reach the site of inflammation smoothly. Meanwhile, MPDA activated DRD2 internalization to stabilize Nrf2. The release of prunetin inhibited the interaction of Kelch-like ECH-associated protein 1 with Nrf2 and promoted the nuclear translocation of Nrf2. In summary, this study unveiled that in skin inflammation, H@P@M activated and internalized DRD2, which subsequently formed a protein complex with arrestin beta 1-ubiquitin specific protease 8 (USP8)-Nrf2. Deubiquitination was performed to stabilize Nrf2 while promoting the nuclear translocation of Nrf2 to exert anti-inflammatory and antioxidant functions. STATEMENT OF SIGNIFICANCE: Skin is the body's largest physical barrier, always protecting the body from the interference of the external environment. However, excessive exposure to ultraviolet rays in the sun can cause skin inflammation, leading to skin erythema, itching, edema and pain, which can be troublesome in our daily lives. The complex mechanism of skin inflammation caused by ultraviolet radiation has not been fully clarified. In this study, the role of DRD2 in UV-induced skin inflammation was explored, and nano-composite particles HA@Prunetin@MPDA, which act on multiple targets in the anti-inflammatory pathway of DRD2, were developed to maximize the effect of the drug. It provides a new way to treat skin inflammation caused by UV.

Pramipexole has a neuroprotective effect in spinal cord injury and upregulates D2 receptor expression in the injured spinal cord tissue in rats

Spinal cord injury (SCI) has emerged as a prevalent condition with limited effective treatment options. The neuroprotective role of pramipexole (PPX) in inhibiting nerve cell apoptosis in central nervous system injuries is well established. Therefore, we investigated the effects of PPX in SCI. Adult Sprague-Dawley rats were divided into four groups (sham, SCI, PPX-0.25, and PPX-2.0 groups) according to the PPX therapy (n = 24). Then, SCI was induced using the modified Allen method, and PPX was intravenously administered into the tail at dosages of 0.25 or 2.0 mg/kg following the injury. Motor function was evaluated using the Rivlin-modified inclined plate apparatus and the Basso Beattie Bresnahan (BBB) workout scale. Western blotting assay was used to measure protein expression levels of DRD2, NeuN, Bax/Bcl-2, and caspase-3. Furthermore, immunohistochemistry assessed the effect of PPX on the quantity of NeuN-positive cells in the spinal cord tissue after SCI. Our findings revealed that the BBB and slanting board test scores of the PPX-treated model groups were considerably higher for the SCI group and significantly lower for the sham operation group (P < 0.001). Moreover, the PPX-2.0 group exhibited significantly higher NeuN expression levels than the SCI group (P < 0.01). Our findings indicate that PPX exerts a neuroprotective effect in secondary neuronal injury following SCI, facilitating the recovery of hind limb function by downregulating Bax/Bcl-2, caspase-3, and IL-1β.

Dopamine receptors D1 and D2 show prognostic significance and potential therapeutic applications for endometrial cancer patients

OBJECTIVE

Catecholaminergic signaling has been a target for therapy in different type of cancers. In this work, we characterized the ADRβ2, DRD1 and DRD2 expression in healthy tissue and endometrial tumors to evaluate their prognostic significance in endometrial cancer (EC), unraveling their possible application as an antitumor therapy.

METHODS

109 EC patients were included. The expression of the ADRβ2, DRD1 and DRD2 proteins was evaluated by immunohistochemistry and univariate and multivariate analysis to assess their association with clinic-pathological and outcome variables. Finally, HEC1A and AN3CA EC cell lines were exposed to different concentrations of selective dopaminergic agents alone or in combination to study their effects on cellular viability.

RESULTS

ADRβ2 protein expression was not associated with clinico-pathological parameters or prognosis. DRD1 protein expression was reduced in tumors samples but showed a significant inverse association with tumor size and stage. DRD2 protein expression was significantly associated with non-endometrioid EC, high grade tumors, tumor size, worse disease-free survival (HR = 3.47 (95%CI:1.35-8.88)) and overall survival (HR = 2.98 (95%CI:1.40-6.34)). The DRD1 agonist fenoldopam showed a reduction of cellular viability in HEC1A and AN3CA cells. The exposure to domperidone, a DRD2 antagonist, significantly reduced cell viability compared to the control. Finally, DRD1 agonism and DRD2 antagonism combination induced a significant reduction in cell viability of the AN3CA cells compared to monotherapy, close to being an additive response than a synergistic effect (CI of 1.1 at 0.5% Fa).

CONCLUSION

DRD1 and DRD2 expression levels showed a significant association with clinico-pathological parameters. Both the combined activation of DRD1 and blockage of DRD2 may form an innovative strategy to inhibit tumor growth in EC.

Clinical and genetic factors associated with post-operative nausea and vomiting after propofol anaesthesia

BACKGROUND

The incidence of post-operative nausea and vomiting (PONV) remains at about 30% despite all therapeutic efforts to reduce it. The clinical risk factors guiding the prophylactic treatment are well established, but genetic factors associated with PONV remain poorly known. The aim of this study was to explore clinical and genetic factors impacting PONV by performing a genome-wide association study (GWAS) together with relevant clinical factors as covariates, and systematically attempt to replicate previously reported PONV associations. Relevant clinical factors are explored with logistic regression model.

METHODS

This was an observational case control study in Helsinki University Hospital between 1 August 2006 and 31 December 2010. One thousand consenting women with elevated risk for PONV, undergoing breast cancer surgery with standardised propofol anaesthesia and antiemetics. After exclusions for clinical reasons and failed genotyping, 815 patients were included with 187 PONV cases and 628 controls. Emergence of PONV up to 7th post-operative day was recorded. PONV at 2-24 h after surgery was selected to be the primary outcome. The GWAS explored associations between PONV and 653 034 genetic variants. Replication attempts included 31 variants in 16 genes.

RESULTS

The overall incidence of PONV up to 7th post-operative day was 35%, where 3% had PONV at 0-2 h and 23% at 2-24 h after surgery. Age, American Society of Anaesthesiologists status, the amount of oxycodone used in the post-anaesthesia care unit, smoking status, previous PONV, and history of motion sickness were statistically significant predictive factors in the logistic model. The receiver operating characteristic-area under the curve of 0.75 (95% CI 0.71-0.79) was calculated for the model. The GWAS identified six variants with suggestive association to PONV (p < 1 × 10-5 ). Of the previously reported variants, association with the DRD2 variant rs18004972 (TaqIA) was replicated (p = .028).

CONCLUSIONS

Our GWAS approach did not identify any high-impact PONV susceptibility variants. The results provide some support for a role of dopamine D2 receptors in PONV.

Shifting as an executive function separate from updating and inhibition in old age: Behavioral and genetic evidence

This study aimed to examine the organization of executive functions (EFs), specifically working memory updating, prepotent response inhibition, and mental-set shifting in old age, with a particular focus on determining whether the shifting function was behaviorally and genetically separated from the other functions. A total of 248 healthy older Chinese individuals participated, and multiple measures of executive functions were collected. Additionally, measures of fluid intelligence were included to explore the varying relationships between the three executive functions and this higher-order cognitive ability. Furthermore, genetic data were gathered and analyzed to investigate the associations between EFs and six candidate single-nucleotide polymorphisms (SNPs) mapped to dopaminergic, serotonergic, or glutamatergic genes. The results indicated that both the three-factor model and the two-factor model, which combined updating and inhibition, demonstrated a good fit. Furthermore, shifting was found to be behaviorally separated from the other two functions, and the correlation between shifting and fluid intelligence was smaller compared to the correlations between updating and inhibition with fluid intelligence. Moreover, the DRD2 SNPs showed significant associations with shifting, rather than with updating and inhibition. These findings provide evidence that shifting is distinct and separate from updating and inhibition, highlighting the diversity of EFs among older adults.

Linkage and association of variants in the dopamine receptor 2 gene (DRD2) with polycystic ovary syndrome

Polycystic ovarian syndrome (PCOS) is a disorder with a foundation of neuroendocrine dysfunction, characterized by increased gonadotropin-releasing hormone (GnRH) pulsatility, which is antagonized by dopamine. The dopamine receptor 2 (DRD2), encoded by the DRD2 gene, has been shown to mediate dopamine's inhibition of GnRH neuron excitability through pre- and post-synaptic interactions in murine models. Further, DRD2 is known to mediate prolactin (PRL) inhibition by dopamine, and high blood level of PRL have been found in more than one third of women with PCOS. We recently identified PRL as a gene contributing to PCOS risk and reported DRD2 conferring risk for type 2 diabetes and depression, which can both coexist with PCOS. Given DRD2 mediating dopamine's action on neuroendocrine profiles and association with metabolic-mental states related to PCOS, polymorphisms in DRD2 may predispose to development of PCOS. Therefore, we aimed to investigate whether DRD2 variants are in linkage to and/or linkage disequilibrium (i.e., linkage and association) with PCOS in Italian families. In 212 Italian families, we tested 22 variants within the DRD2 gene for linkage and linkage disequilibrium with PCOS. We identified five novel variants significantly linked to the risk of PCOS. This is the first study to identify DRD2 as a risk gene in PCOS, however, functional studies are needed to confirm these results.

Chronic stress accelerates glioblastoma progression via DRD2/ERK/β-catenin axis and Dopamine/ERK/TH positive feedback loop

BACKGROUND

After diagnosis, glioblastoma (GBM) patients undertake tremendous psychological problems such as anxiety and depression, which may contribute to GBM progression. However, systematic study about the relationship between depression and GBM progression is still lacking.

METHODS

Chronic unpredictable mild stress and chronic restrain stress were used to mimic human depression in mice. Human GBM cells and intracranial GBM model were used to assess the effects of chronic stress on GBM growth. Targeted neurotransmitter sequencing, RNA-seq, immunoblotting and immunohistochemistry were used to detect the related molecular mechanism.

RESULTS

Chronic stress promoted GBM progression and up-regulated the level of dopamine (DA) and its receptor type 2 (DRD2) in tumor tissues. Down-regulation or inhibition of DRD2 abolished the promoting effect of chronic stress on GBM progression. Mechanistically, the elevated DA and DRD2 activated ERK1/2 and consequently inhibited GSK3β activity, leading to β-catenin activation. Meanwhile, the activated ERK1/2 up-regulated tyrosine hydroxylase (TH) level in GBM cells and then promoted DA secretion, forming an autocrine positive feedback loop. Remarkably, patients with high-depression exhibited high DRD2 and β-catenin levels, which showed poor prognosis. Additionally, DRD2 specific inhibitor pimozide combined with temozolomide synergistically inhibited GBM growth.

CONCLUSIONS

Our study revealed that chronic stress accelerates GBM progression via DRD2/ERK/β-catenin axis and Dopamine/ERK/TH positive feedback loop. DRD2 together with β-catenin may serve as a potential predictive biomarker for worse prognosis as well as therapeutic target of GBM patients with depression.

The ANKK1/DRD2 gene TaqIA polymorphism (rs1800497) is associated with the severity of extrapyramidal side effects of haloperidol treatment in CYP2D6 extensive metabolizers with schizophrenia spectrum disorders

OBJECTIVES

Extrapyramidal symptoms (EPS) are one of the most prominent side effects of haloperidol. Variability of EPS severity may be associated with the genetic factors, affecting both haloperidol pharmacokinetics (e.g., CYP2D6) and pharmacodynamics (e.g., DRD2, ANKK1). We conducted a 3-week prospective study to investigate the associations of ANKK1/DRD2 TaqIA (rs1800497), DRD2 -141C Ins/Del (rs1799732) polymorphisms and CYP2D6 metabolic phenotype on the efficacy of haloperidol treatment and severity of EPS in patients with schizophrenia spectrum disorders.

METHODS

In total, 57 inpatients with schizophrenia spectrum disorders (24 (42.1%)) females; age -46.7 (11.8) years (M(SD)) of European ancestry were enrolled. BARS and SAS scales were used to assess EPS. PANSS and CGI scales - to assess the efficacy of haloperidol treatment. Genotyping was performed by real-time PCR. CYP2D6 metabolic phenotype was predicted by the CYP2D6 *3, *4, *5, *6, *9, *10, *41 and xN genotypes.

RESULTS

Minor C allele of TaqIA was associated with higher scores of BARS (p=0.029) and SAS (p=0.024) on day 21 and minor Del allele of -141C Ins/Del - with more prominent clinical improvement by CGI scale (p=0.007) but not by PANSS. These differences were observed only in extensive CYP2D6 metabolizers, although no associations with the metabolic type itself were found. General linear model showed that the combination of TaqIA genotype and metabolic type was significantly associated with BARS score on day 21 (p=0.013).

CONCLUSIONS

Our results highlight the importance of using both pharmacokinetic and pharmacodynamic genetic markers for predicting haloperidol treatment response to personalize schizophrenia spectrum disorders treatment.

Functional single nucleotide polymorphisms in dopaminergic receptors D2 predict clinical response to Cariprazine

Cariprazine (CAR) is an antipsychotic drug for the treatment of schizophrenia (SCZ) and bipolar disorder (BD), and it acts as a partial agonist on the dopamine receptors (DR), D2, and D3. Although many single nucleotide polymorphisms (SNPs) in genes coding for these receptors are known to influence response to antipsychotics, to date, no study on CAR pharmacogenetics exists. In this pilot study, we investigated the relationship between SNPs in DRD2 (rs1800497 and rs6277) and DRD3 (rs6280), and response to CAR treatment, evaluated by the psychometric Brief Psychiatric Rating Scale (BPRS), in a cohort of Caucasian patients. We found a significant association between DRD2 rs1800497 and rs6277 and response to CAR treatment. When genotypes were combined into an arbitrary score, the receiver operating characteristic curve analysis showed that using a cut-off value of -2.5 the response to CAR treatment could be predicted with a positive likelihood ratio of 8.0. Our study report, for the first time, a correlation between SNPs in DRD2 and response to CAR treatment. After confirmation in a larger cohort of patients, our results could open the way for the identification of new tools for the provision of response to CAR treatment.

Assessment of genetic variants in D2 dopamine receptor (DRD2) gene as risk factors for post-traumatic stress disorder (PTSD) and major depressive disorder (MDD): A systematic review and meta-analysis

BACKGROUND

Many studies have performed assessments of genetic variants in the D2 dopamine receptor (DRD2) gene as risk factors for post-traumatic stress disorder (PTSD) and major depressive disorder (MDD). However, the results are inconsistent. This meta-analysis aimed to systematically summarize published data to evaluate the reliable association between the DRD2 genetic variants and the risk of PTSD and MDD.

METHODS

A systematic literature search was conducted using the Web of Science, PubMed, Google Scholar, Excerpta Medica Database (EMBASE), Springer, ScienceDirect, Wiley Online Library, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database (CBM), WANFANG Data, CQVIP, and Chinese National Knowledge Infrastructure (CNKI) databases before January 1st, 2022.

RESULTS

A total of 27 genetic variants in the DRD2 gene were retrieved, and 7 of them met the inclusion criteria for meta-analysis. Our meta-analysis results indicated that the rs1800497 (TaqIA) polymorphism was significantly associated with the increased risk of PTSD (Dominant model (A1A1 + A1A2 vs. A2A2): OR = 1.49, 95 % CI, 1.08-2.04 Z = 2.46, P = 0.014). Subgroup analysis for ethnicity suggested that a significantly increased risk of PTSD was observed in Asians (Dominant model (A1A1 + A1A2 vs. A2A2): OR = 1.39, 95 % CI, 1.08-1.79, Z = 2.60, P = 0.009) and Caucasians (Dominant model (A1A1 + A1A2 vs. A2A2): OR = 1.87, 95 % CI 1.02-3.41, Z = 2.04, P = 0.042). Meanwhile, we detected significant association strengths between the rs1799978 and rs2075652 polymorphisms in the DRD2 gene and MDD (for rs1799978, Homozygote comparison (GG vs. AA): OR = 0.60, 95 % CI = 0.37-0.97, Z = 2.08, P = 0.038; for rs2075652, Homozygote comparison (AA vs. GG): OR = 1.82, 95 % CI = 1.32-2.50, Z = 3.67, P < 0.001). Our cumulative meta-analyses indicated a continuous trend toward association strength with PTSD and MDD.

CONCLUSIONS

This meta-analysis indicated that genetic variants in the DRD2 gene might potentially contribute to genetic susceptibility for PTSD and MDD. The utilization of DRD2 genetic variants as risk factors for PTSD and MDD requires further validation by large well-designed case-control studies.

Associations between variants in levodopa metabolic pathway genes and levodopa-induced dyskinesia in Parkinson's disease

INTRODUCTION

Levodopa-induced dyskinesia (LID) is a common motor complication in Parkinson's disease (PD). Several genes in the levodopa metabolic pathway, such as COMT, DRDx and MAO-B, were reported associated with LID. However, there has been no systematic analyses between common variants in levodopa metabolic pathway genes and LID in a large sample of the Chinese population.

METHODS

Through the whole exome sequencing (WES) and target region sequencing, we aimed to explore the potential associations between common single nucleotide polymorphisms (SNPs) in the levodopa metabolic pathway and LID in Chinese PD individuals. Five hundred and two PD individuals were enrolled in our study, among them, 348 individuals underwent WES, and 154 individuals underwent target region sequencing. We acquired the genetic profile of 11 genes including COMT, DDC, DRD1-5, SLC6A3, TH and MAO-A/B. We established a stepwise strategy to filter SNPs, which finally included 34 SNPs in our analyses. And we used a two-stage study, with discovery (348 individuals with WES) and the replication (all 502 individuals) to confirm our findings.

RESULTS

Among the 502 PD individuals, 104 (20.7%) were diagnosed with LID. In the discovery stage, we found that COMT rs6269, DRD2 rs6275 and DRD2 rs1076560 were associated with LID. In the replication stage, associations between the three above-mentioned SNPs and LID were still present in all 502 individuals.

CONCLUSION

We demonstrated that in the Chinese population, COMT rs6269, DRD2 rs6275 and rs1076560 were significantly associated with LID. And rs6275 was reported associated with LID for the first time.

Rasd2 Mediates Acute Fasting-Induced Antidepressant-Like Effects via Dopamine D2 Receptor Activation in Ovariectomized Mice

BACKGROUND

Previous studies have shown that estrogen and acute fasting for 9 hours have antidepressant-like effects by reducing immobility time in the forced swimming test. Estrogen and acute fasting share a common regulatory gene, Rasd2. RASD2 regulates dopamine D2 receptor (DRD2) transmission, but the role of Rasd2 in the DRD2-mediated antidepressant-like effect of acute fasting has not been examined.

METHODS

In this study, open field test, forced swimming test, tail suspension test and sucrose preference test were used for behavioral assessments. RNA-seq, western blot, enzyme-linked immunosorbent assay, and co-immunoprecipitation were used to explore the role of Rasd2 in a depression model induced by ovariectomy and the antidepressant-like effects of 9-hour fasting.

RESULTS

The RNA seq results showed that acute fasting induced a significant change in Rasd2 gene expression. Depression-like behaviors induced by ovariectomy were associated with decreased RASD2 and DRD2 protein levels in the hippocampus, and Rasd2 overexpression in the hippocampus alleviated depression-like behaviors and increased DRD2 expression. Nine-hour fasting had antidepressant-like effects in ovariectomized mice by upregulating the protein levels of RASD2, DRD2, CREB-BDNF, Akt, and estrogen receptor beta, and these effects can be blocked by DRD2 antagonists.

CONCLUSIONS

Our results suggest that Rasd2 and DRD2 play pivotal roles in depression-like behavior induced by ovariectomy. Rasd2 regulates DRD2-mediated antidepressant-like effects of acute fasting in ovariectomized mice. Rasd2 can therefore be postulated to be a potential therapeutic target for depression and perhaps also a potential predictive marker for depression.

DNA Methylation Pattern of Gene Promoters of MB-COMT, DRD2, and NR3C1 in Turkish Patients Diagnosed with Schizophrenia

OBJECTIVE

We aim to evaluate the methylation status of membrane-bound catechol-O-methyltransferase (MB-COMT) promotor, dopamine receptor D2 (DRD2), and nuclear receptor subfamily 3 group C member 1 (NR3C1) gene in pa- tients with SCZ by comparing healthy controls.

METHODS

A sample of 110 patients with SCZ and 100 age- and sex-matched healthy volunteers was included in the study. The interview was started by filling out data forms that included sociodemographic and clinical information. The Structured Clinical Interview for DSM-IV Axis I Disorders was used to confirming the diagnosis according to DSM-IV-TR criteria. Then the patients were evaluated with the Positive and Negative Symptoms Scale in terms of symp- tom severity. Methylation-specific polymerase chain reaction was used to determine the methylation status of MB-COMT promotor, DRD2 , and NR3C1 gene from DNA material.

RESULTS

When we compared the percentages of MB-COMT promotor, DRD2, and NR3C1 gene methylation status in SCZ patients with the healthy control group, the percentages of MB-COMT promotor (OR: 0.466; 95% CI: 0.268- 0.809; p = 0.006), DRD2 (OR: 0.439; 95% CI: 0.375-0.514; p < 0.001), and NR3C1 (OR: 0.003; 95% CI: 0.001- 0.011; p < 0.001) gene methylation status of SCZ was found to be significantly different from the control group. Whereas unmethylation of MB-COMT promotor and NR3C1 genes were associated with SCZ, the partial methylation of the DRD2 gene was related to the SCZ.

CONCLUSION

The MB-COMT promotor, DRD2, and NR3C1 gene methylation status may be associated with the SCZ in the Turkish population.

Developing Photoaffinity Probes for Dopamine Receptor D2 to Determine Targets of Parkinson's Disease Drugs

Dopaminergic pathways control highly consequential aspects of physiology and behavior. One of the most therapeutically important and best-studied receptors in these pathways is dopamine receptor D₂ (DRD2). Unfortunately, DRD2 is challenging to study with traditional molecular biological techniques, and most drugs designed to target DRD2 are ligands for many other receptors. Here, we developed probes able to both covalently bind to DRD2 using photoaffinity labeling and provide a chemical handle for detection or affinity purification. These probes behaved like good DRD2 agonists in traditional biochemical assays and were able to perform in chemical-biological assays of cell and receptor labeling. Rat whole brain labeling and affinity enrichment using the probes permitted proteomic analysis of the probes' interacting proteins. Bioinformatic study of the hits revealed that the probes bound noncanonically targeted proteins in Parkinson's disease network as well as the retrograde endocannabinoid signaling, neuronal nitric oxide synthase, muscarinic acetylcholine receptor M1, GABA receptor, and dopamine receptor D₁ (DRD1) signaling networks. Follow-up analysis may yield insights into how this pathway relates specifically to Parkinson's disease symptoms or provide new targets for treatments. This work reinforces the notion that the combination of chemical biology and omics-based approaches provides a broad picture of a molecule's "interactome" and may also give insight into the pleiotropy of effects observed for a drug or perhaps indicate new applications.

Association of Polymorphism within the Putative miRNA Target Site in the 3'UTR Region of the DRD2 Gene with Neuroticism in Patients with Substance Use Disorder

The study aims at looking into associations between the polymorphism rs6276 that occurs in the putative miRNA target site in the 3'UTR region of the DRD2 gene in patients with substance use disorder (SUD) comorbid with a maniacal syndrome (SUD MANIA). In our study, we did not state any essential difference in DRD2 rs6276 genotype frequencies in the studied samples of SUD MANIA, SUD, and control subjects. A significant result was found for the SUD MANIA group vs. SUD vs. controls on the Neuroticism Scale of NEO FFI test, and DRD2 rs6276 (p = 0.0320) accounted for 1.7% of the variance. The G/G homozygous variants were linked with lower results on the neuroticism scale in the SUD MANIA group because G/G alleles may serve a protective role in the expression of neuroticism in patients with SUD MANIA. So far, there have been no data in the literature on the relationship between the miRSNP rs6276 region in the DRD2 gene and neuroticism (personal traits) in patients with a diagnosis of substance use disorder comorbid with the affective, maniacal type disturbances related to SUD. This is the first report on this topic.

Emotional Intelligence in Carriers of Different СОМТ, BDNF, DRD2 and HTR2A Genotypes

Background

Emotional intelligence is the ability to quickly and correctly recognize the emotional expressions of other people and to express and manage one's own emotions. It contributes to the success of a person in activities related to communication and interaction with people. Emotional intelligence has been studied largely in the context of organizational and education psychology, but less is known about the influence of genetics on it.

Objective

We aim to study emotional intelligence in carriers of different СОМТ, BDNF, DRD2, and HTR2A genotypes.

Design

We used three methods to measure emotional intelligence. Mayer-Salovey-Caruso Emotional Intelligence Test is a set of tasks with forced choice and frequency-based correct responses. We also applied two self-report questionnaires by Lyusin and Hall. We recruited 280 participants who took part in all three measures. We also identified their genotypes of the СОМТ, BDNF, DRD2, and HTR2A genes.

Results

Carriers of the Val/Met genotype of the COMT gene, A/A genotype of the HTR2A gene and C/C genotype of the DRD2 gene showed the highest level of emotional intelligence, while no differences were found between carriers of the BDNF genotypes. These data were obtained by using the Mayer-Salovey-Caruso Emotional Intelligence Test. Self-report scores of emotional intelligence did not differ between carriers of different genotypes across all four of the genes in question.

Conclusion

Mayer-Salovey-Caruso Emotional Intelligence Test scores were differed for carriers of some genotypes, whereas self-reported emotional intelligence scores did not differ between according to genotype.

A Randomized, Sham-Controlled Trial of Repetitive Transcranial Magnetic Stimulation Targeting M1 and S2 in Central Poststroke Pain: A Pilot Trial

OBJECTIVES

Central poststroke pain (CPSP), a neuropathic pain condition, is difficult to treat. Repetitive transcranial magnetic stimulation (rTMS) targeted to the primary motor cortex (M1) can alleviate the condition, but not all patients respond. We aimed to assess a promising alternative rTMS target, the secondary somatosensory cortex (S2), for CPSP treatment.

MATERIALS AND METHODS

This prospective, randomized, double-blind, sham-controlled three-arm crossover trial assessed navigated rTMS (nrTMS) targeted to M1 and S2 (10 sessions, 5050 pulses per session at 10 Hz). Participants were evaluated for pain, depression, anxiety, health-related quality of life, upper limb function, and three plasticity-related gene polymorphisms including Dopamine D2 Receptor (DRD2). We monitored pain intensity and interference before and during stimulations and at one month. A conditioned pain modulation test was performed using the cold pressor test. This assessed the efficacy of the descending inhibitory system, which may transmit TMS effects in pain control.

RESULTS

We prescreened 73 patients, screened 29, and included 21, of whom 17 completed the trial. NrTMS targeted to S2 resulted in long-term (from baseline to one-month follow-up) pain intensity reduction of ≥30% in 18% (3/17) of participants. All stimulations showed a short-term effect on pain (17-20% pain relief), with no difference between M1, S2, or sham stimulations, indicating a strong placebo effect. Only nrTMS targeted to S2 resulted in a significant long-term pain intensity reduction (15% pain relief). The cold pressor test reduced CPSP pain intensity significantly (p = 0.001), indicating functioning descending inhibitory controls. The homozygous DRD2 T/T genotype is associated with the M1 stimulation response.

CONCLUSIONS

S2 is a promising nrTMS target in the treatment of CPSP. The DRD2 T/T genotype might be a biomarker for M1 nrTMS response, but this needs confirmation from a larger study.

The correlation between genetic factors and freezing of gait in patients with Parkinson's disease

BACKGROUND

Clinical-related risk factors to freezing of gait (FOG) in Parkinson's disease (PD) have been identified. Still, the influence of genetic variations on the FOG occurrence has been poorly studied thus far.

AIM

We aimed to evaluate the association of six selected polymorphisms of DRD2, ANKK1, and COMT genes with the FOG occurrence and explore the influence of ANNK1/DRD2 haplotypes on the onset of FOG in the group of PD patients.

METHOD

PD patients (n = 234), treated with levodopa for at least two years, were genotyped for the rs4680 in COMT, rs6277, rs1076560, and rs2283265 in DRD2, and rs1800497 and rs2734849 polymorphisms in ANKK1 genes. FOG was evaluated by posing a direct question. In addition, a comprehensive set of clinical scales was applied to all patients.

RESULTS

FOG occurred in 132 (56.4%) PD patients in our cohort. Freezers were younger at PD onset, had longer disease duration, used higher levodopa daily doses and dopaminergic agents, and had higher motor and non-motor scales scores than non-freezers. FOG was more frequent among AA rs4680 COMT carriers than AG and GG rs4680 COMT carriers. Independent predictors of FOG were: disease duration of more than ten years, levodopa daily dose higher than 500 mg/day, motor status, and COMT AA genotype. AGGAA and GGAAA haplotypes were revealed as protective and vulnerability factors for FOG occurrence.

CONCLUSION

In addition to previously identified disease- and therapy-related risk factors, our results suggested a possible contribution of dopamine-related genes to the FOG occurrence.

Association Between DRD2 and DRD4 Polymorphisms and Eating Disorders in an Italian Population

Anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED) are the three most common eating disorders (EDs). Their etiopathogenesis is multifactorial where both the environmental and genetic factors contribute to the disease outcome and severity. Several polymorphisms in genes involved in the dopaminergic pathways seem to be relevant in the susceptibility to EDs, but their role has not been fully elucidated yet. In this study, we have analyzed the association between selected common polymorphisms in the DRD2 and DRD4 genes in a large cohort of Italian patients affected by AN (n = 332), BN (n = 122), and BED (n = 132) compared to healthy controls (CTRs) (n = 172). Allelic and genotypic frequencies have been also correlated with the main psychopathological and clinical comorbidities often observed in patients. Our results showed significant associations of the DRD2-rs6277 single nucleotide polymorphism (SNP) with AN and BN, of the DRD4-rs936461 SNP with BN and BED and of DRD4 120-bp tandem repeat (TR) polymorphism (SS plus LS genotypes) with BED susceptibility. Moreover, genotyping of DRD4 48-bp variable number TR (VNTR) identified the presence of ≥7R alleles as risk factors to develop each type of EDs. The study also showed that ED subjects with a history of drugs abuse were characterized by a significantly higher frequency of the DRD4 rs1800955 TT genotype and DRD4 120-bp TR short-allele. Our findings suggest that specific combinations of variants in the DRD2 and DRD4 genes are predisposing factors not only for EDs but also for some psychopathological features often coupled specifically to AN, BN, and BED. Further functional research studies are needed to better clarify the complex role of these proteins and to develop novel therapeutic compounds based on dopamine modulation.

Methylation of APC2, NR3C1, and DRD2 gene promoters in turkish patients with tobacco use disorder

Background

Many studies have investigated the association of the methylation of gene and tobacco use disorders (TUD), but results remain ambiguous.

Aims

This study evaluated the relationship between methylation of Adenomatosis Polyposis Coli (APC), Nuclear Receptor subfamily 3 group C member 1 (NR3C1), Dopamine D2 receptor (DRD2) gene promoters, and its effect on TUD.

Subjects and Methods

We recruited 154 active smokers and 111 healthy non-smoker controls. PCR based methods on genomic DNA characterized the methylation of APC2, NR3C1, and DRD2 gene promoters.

Results

We have found a significant difference in methylation of APC2 for TUD compared to healthy controls (P < 0.001). The partial methylation ratio was about an eight-fold increase in smokers compared to healthy controls. NR3C1 methylation was slightly higher in TUD patients compared to the control group, but the difference was not significant between the two groups (%95.33 vs. 91.08, P = 0.269). DRD2 methylation ratio was not significant between TUD patients and healthy control groups (P = 0.894).

Conclusion

We think that it is important to detect APC2 methylated cases earlier and to advise them to quit smoking.

Quantitative behavioral genetic and molecular genetic foundations of the approach and avoidance strategies

Two studies examined genetic and environmental influences on traits proposed by the revised Reinforcement Sensitivity Theory (rRST) of personality. Both quantitative and molecular behavioral genetic methods were applied considering the effects of COMT, DRD2, HTR1A and TPH2 single nucleotide polymorphisms (SNPs). Study one included 274 monozygotic and 154 dizygotic twins for the quantitative behavioral study; and in study two there were 431 twins for the molecular genetic study. The Reinforcement Sensitivity Questionnaire was used to assess basic personality traits defined by the rRST. Univariate biometric modeling suggested that genetic influences accounted for 34-44% of variance of Behavioral Approach System (BAS), Behavioral Inhibition System (BIS) and Fight-Fligh-Freeze System. Molecular genetic analyses proposed the significant main effect of COMT SNP on the BAS and TPH2 SNP on the BIS, and pointed out epistatic effects of COMT x DRD2 on BAS and HTR1A x TPH2 on Fight. Results demonstrated substantial heritability for all rRST constructs, as well as for differences in the molecular genetic basis of both approach-related and avoidance-related dimensions.

Fatigue in breast cancer patients on chemotherapy: a cross-sectional study exploring clinical, biological, and genetic factors

Background

Cancer-related fatigue (CRF) is one of the most common and distressing complaints reported by cancer patients during chemotherapy considerably impacting all aspects of a patient’s life (physical, psychosocial, professional, and socioeconomic). The aim of this study was to assess the severity of cancer-related fatigue in a group of breast cancer patients undergoing chemotherapy and explore the association between fatigue scores and sociodemographic, clinical, biological, psychiatric, and genetic factors.

Methods

A cross-sectional pilot study carried out at the oncology outpatient unit of Hôtel-Dieu de France University Hospital recruited 67 breast cancer patients undergoing chemotherapy between November 2017 and June 2019 to evaluate fatigue using the EORTC QLQ-C30 scale (European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire). Genotyping for seven gene polymorphisms (COMT, DRD2, OPRM1, CLOCK, PER2, CRY2, ABCB1) was performed using the Lightcycler^® (Roche).

Results

The prevalence of fatigue was 46.3%. Multivariable analysis taking the fatigue score as the dependent variable showed that a higher number of cycles and a lower hemoglobin level were significantly associated with higher odds of exhibiting fatigue. Moreover, having at least one C allele for DRD2 SNP (vs. TT) was significantly associated with a 4.09 higher odds of expressing fatigue compared to TT patients. Finally, patients with at least one C allele for CLOCK SNP tended to display higher fatigue levels than TT patients.

Conclusions

Our study showed that anemic breast cancer patients with a high number of chemotherapy cycles and those carrying at least one C allele for DRD2 and CLOCK SNPs are at greater risk of exhibiting fatigue. Since no previous research has reported such genetic results, future studies are necessary to confirm our findings.

GABAA subunit single nucleotide polymorphisms show sex-specific association to alcohol consumption and mental distress in a Norwegian population-based sample

Little is known about genetic influences on the relationship between alcohol consumption and mental distress in the general population, where the majority report consumption and distress far below diagnostic thresholds. This study investigated single nucleotide polymorphisms (SNPs) from candidate gene studies on alcohol use disorder and depressive disorders, for association with alcohol consumption and with mental distress in a population-based sample from the Cohort of Norway (n = 1978, 49% women). The relationship between alcohol consumption and mental distress was further examined for genotype modification. There was a positive correlation between mental distress and alcohol consumption in men, as well as an association between SNPs and mental distress in men (GABRG1, GABRA2, DRD2, ANKK1, MTHFR) and women (CHRM2, MTHFR) and between SNPs and alcohol consumption in women (GABRA2, MTHFR). No modification by SNP genotype was found on the relationship between alcohol consumption and mental distress. The association between mental distress and GABRG1 in men remained significant after correcting for multiple comparisons. The results indicate that alcohol consumption and mental distress are associated in the general population even at levels below clinical thresholds and point to SNPs in genes related to GABAergic signalling for level of mental distress in men.

Effects of OPRM1 and DRD2 on brain structure in drug-naïve adolescents: Genetic and neural vulnerabilities to substance use

Genetic variants in the opioid receptor mu 1 (OPRM1) and dopamine receptor d2 (DRD2) genes are implicated in behavioral phenotypes related to substance use disorders (SUD). Despite associations among OPRM1 (rs179971) and DRD2 (rs6277) genes and structural alterations in neural reward pathways implicated in SUDs, little is known about the contribution of risk-related gene variants to structural neurodevelopment. In a 3-year longitudinal study of initially SU-naïve adolescents (N = 129; 70 females; 11-14 years old), participants underwent an MRI structural scan at baseline and provided genetic assays for OPRM1 and DRD2 with SU behavior assessed during follow-up visits. Baseline differences in key reward-related brain regions (i.e., bilateral caudate and cingulate cortex) were detected in those with genetic liability for SU in OPRM1 who went onto engage in SU at subsequent waves of data collection. In addition, main effects of OPRM1, DRD2, and SU were related to variability in structure of the putamen, anterior cingulate, and nucleus accumbens, respectively. These data provide preliminary evidence that genetic risk factors interact with future SU to confer structural variability prior to SU in regions commonly implicated in risk for SU and the development of SUDs.

Long-term effects of adolescent sport experience, DRD2 and COMT genes, and their interaction on sport participation in adulthood

BACKGROUND

The present study investigated the joint impact of adolescent sport experience and dopamine-related genes (i.e., DRD2 and COMT genes) on sport participation in adulthood.

METHODS

Using the National Longitudinal Study of Adolescent Health (Add Health) data, the hierarchical multivariable logistic regression models for predicting sport participation in wave 3 (around 20 years of age) and wave 4 (around 30 years of age) were conducted separately by gender (male and female) and gene (DRD2 and COMT genes).

RESULTS

Adolescent sport experience significantly interacted with the number of DRD2 A1 alleles and COMT Met alleles in affecting wave 3 sport participation among male adults. The interaction between adolescent sport experience and DRD2 gene significantly affected wave 4 sport participation in opposite direction to that affected wave 3 sport participation among male participants. Among female participants, there were no significant interaction effects between dopamine-related genes and adolescent sport experience on sport participation in both wave 3 and 4.

CONCLUSIONS

Since adult sport participation is most likely to be influenced by the joint impact of environmental and genetic factors, it is important to consider gene-by-environment interactions when designing policies or programs to promote adult sport participation.

Maternal Deprivation Increased Vulnerability to Depression in Adult Rats Through DRD2 Promoter Methylation in the Ventral Tegmental Area

OBJECTIVE

Early life adversity is a risk factor for depression in adulthood; however, the underlying mechanisms are not well understood. This study aims to investigate the effect of DNA methylation of DRD2 gene on early life stress-induced depression in adult rats.

METHODS

Newborn Sprague-Dawley rats were randomly assigned to four groups: maternal deprivation group (MD), chronic unpredictable stress (CUS) group, maternal deprivation plus chronic unpredictable stress (MD/CUS) group, and normal control group (NOR). Behaviors were measured by open field test (OFT), sucrose preference test (SPT), and Original Research Article forced swimming test (FST). Fecal CORT level was detected by ELISA. Bisulfite amplicon sequencing PCR was used to assess methylation levels of DRD2 promoter.

RESULTS

CUS and MD/CUS rats had a significantly shorter total distance, longer immobility time, and higher CORT level, while MD and MD/CUS rats had a significantly lower percentage of central distance, more feces, lower rate of sucrose preference, and lower levels of DRD2 protein and mRNA in the VTA than NOR rats. CUS rats showed a significantly higher DRD2 mRNA and protein levels in the VTA than NOR rats. CUS, MD, and MD/CUS rats showed a significantly higher level of DRD2 promoter methylation than NOR rats. CORT level was significantly correlated with the sucrose preference rate in SPT, the immobility time in FST, the total distance, and the number of fecal pellets in OFT. DRD2 protein level was significantly correlated with the sucrose preference rate and the number of fecal pellets. DRD2 mRNA level was significantly correlated with the percentage of central distance and the number of fecal pellets in OFT. The level of DRD2 promoter methylation was significantly correlated with the sucrose preference rate, immobility time, total distance, the percentage of central distance, and the number of fecal pellets.

CONCLUSIONS

Early life MD increased vulnerability to stress-induced depressive-like behavior in adult rats. Enhanced DRD2 promoter methylation in the VTA may increase the susceptibility to depression.

Dopamine-neurotransmission and nociception in zebrafish: An anti-nociceptive role of dopamine receptor drd2a

Dopamine (DA) is an important modulator in nociception and analgesia. Spinal DA receptors are involved in descending modulation of the nociceptive transmission. Genetic variations within DA neurotransmission have been associated with altered pain sensitivity and development of chronic pain syndromes. The variant rs6277 in dopamine receptor 2 a (drd2a) has been associated with a decreased D₂ receptor availability and increased nociception. The aim of this study is to further characterize the role of DA neurotransmission in nociception and the anti-nociceptive function of drd2a. The phenotype caused by rs6277 was modelled in zebrafish larvae using morpholino's and the effect on nociception was tested using a validated behavioural assay. The anti-nociceptive role of drd2a was tested using pharmacological intervention of D₂ agonist Quinpirole. The experiments demonstrate that a decrease in drd2a expression results in a pro-nociceptive behavioural phenotype (P = 0.016) after a heat stimulus. Furthermore, agonism of drd2a with agonist Quinpirole (0.2 μM) results in dose-dependent anti-nociception (P = 0.035) after a heat stimulus. From these results it is concluded that the dopamine receptor drd2a is involved in anti-nociceptive behaviour in zebrafish. The model allows further screening and testing of genetic variation and treatment involved in nociception.

Clinical and Genetic Factors Associated With the Breast Cancer-Related Sleep Disorders: The "CAGE-Sleep" Study-A Cross-Sectional Study

CONTEXT

Despite being among the most reported concerns in breast cancer patients, sleep disturbances are still poorly assessed and managed in routine clinical practice. Correctly evaluating these symptoms and understanding the underlying clinical and genetic factors would help medical teams develop an adequate treatment strategy for each patient.

OBJECTIVES

1) To explore the severity of insomnia as well as sleep quality in a sample of Lebanese women with breast cancer undergoing chemotherapy; 2) To examine the correlation between sociodemographic, clinical, psychiatric (anxiety and depression), genetic factors, and alterations in sleep patterns.

METHODS

A cross-sectional study was carried out using the Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index (ISI) (December 2017-June 2019; Ethical reference number: CEHDF1016). All patients gave their written consent and were genotyped for several polymorphisms in CLOCK, CRY2, PER2, COMT, DRD2, OPRM1, and ABCB1 genes using Lightcycler® (Roche).

RESULTS

Our sample included a total of 112 women. Almost half of the patients reported insomnia problems (with 20.5% moderate insomnia and 7.1% severe insomnia). Multivariable analyses taking the PSQI score as the dependent variable, showed that higher depression score and dyslipidemia (yes versus no) were significantly associated with higher PSQI scores (worse sleep quality), whereas having the DRD2 CT genotype versus CC and a higher chemotherapy cycle number were significantly associated with lower PSQI scores (better sleep quality). Depression was also significantly associated with higher ISI scores. When forcing all the genes in each model, the results remained the same except for depression that has been replaced by anxiety in the multivariable analysis.

CONCLUSION

Our study confirms the relationship between anxiety/depression, cycle number, dyslipidemia and DRD2 polymorphism with insomnia and highlights the importance of treating all associated factors to improve the overall QOL of patients.

Paliperidone Inhibits Glioblastoma Growth in Mouse Brain Tumor Model and Reduces PD-L1 Expression

Simple Summary

The present study showed that a prescribed psychotropic medicine paliperidone inhibits GBM growth and prolongs survival in mouse brain tumor model and decreased the programmed death ligand 1 expression. Using the 3D co-culture also found that dopamine receptor D2 regulates the interaction of GBM-macrophage-induced PD-L1 expression in GBMs. In addition, the expression of DRD2 and PD-L1 in GBM modulates tumor-associated macrophage polarization. Our results also indicated that there is a contact-independent mechanism of PD-L1 induction in GBM upon interaction between GBM and monocytes. The present study also found that the interaction of GBM-macrophage-enhanced PD-L1 expression in GBM occurred by modulating the ERK and STAT3 signaling pathways. In addition, the inhibition of DRD2 reduces the upregulation of PD-1 expression, and it is regulating signaling in GBM.

Abstract

A previous study from our group reported that monocyte adhesion to glioblastoma (GBM) promoted tumor growth and invasion activity and increased tumor-associated macrophages (TAMs) proliferation and inflammatory mediator secretion as well. The present study showed that prescribed psychotropic medicine paliperidone reduced GBM growth and immune checkpoint protein programmed death ligand (PD-L)1 expression and increased survival in an intracranial xenograft mouse model. An analysis of the database of patients with glioma showed that the levels of PD-L1 and dopamine receptor D (DRD)2 were higher in the GBM group than in the low grade astrocytoma and non-tumor groups. In addition, GFP expressing GBM (GBM-GFP) cells co-cultured with monocytes-differentiated macrophage enhanced PD-L1 expression in GBM cells. The enhancement of PD-L1 in GBM was antagonized by paliperidone and risperidone as well as DRD2 selective inhibitor L741426. The expression of CD206 (M2 phenotype marker) was observed to be markedly increased in bone marrow-derived macrophages (BMDMs) co-cultured with GBM. Importantly, treatment with paliperidone effectively decreased CD206 and also dramatically increased CD80 (M1 phenotype marker) in BMDMs. We have previously established a PD-L1 GBM-GFP cell line that stably expresses PD-L1. Experiments showed that the expressions of CD206 was increased and CD80 was mildly decreased in the BMDMs co-cultured with PD-L1 GBM-GFP cells. On the other hands, knockdown of DRD2 expression in GBM cells dramatically decreased the expression of CD206 but markedly increased CD80 expressions in BMDMs. The present study suggests that DRD2 may be involved in regulating the PD-L1 expression in GBM and the microenvironment of GBM. Our results provide a valuable therapeutic strategy and indicate that treatments combining DRD2 antagonist paliperidone with standard immunotherapy may be beneficial for GBM treatment.

Genotypes of ANKK1 and DRD2 genes and risk of metabolic syndrome and its components: A cross-sectional study on Iranian women

We aimed to investigate the association between polymorphism of DRD2/ANKK1 gene with MetS and its components. Women (n = 531, aged 19-50 years) from the North-west of Iran were included by cluster sampling method. Polymorphisms of ANKK1 and DRD2 genes were defined in the study population. D/D (OR: 3.16; 95%CI: 1.31-7.60) and I/D (OR: 1.76; 95%CI: 1.12-2.78) genotypes of DRD2 (rs1799732) increased risk of MetS compared to I/I genotype. The D/D genotype of DRD2 (rs1799732) increased odds of hypertriglyceridemia in the study population. T/T (OR: 6.72; 95%CI: 1.99-22.71) and C/T (OR: 4.42; 95%CI: 2.79-7.01) genotypes of ANKK1 (rs1800497) increased risk of MetS compared to C/C genotype. Also, C/T genotype increased the odds of HTN, high FBS, high TG and low HDL-C levels compared to C/C genotype. These polymorphisms can affect the MetS components via their relation to the signaling of dopaminergic pathways and eating behaviors.

Analysis of Selected Variants of DRD2 and ANKK1 Genes in Combat Athletes

The level of physical activity is conditioned by many different factors, including, among others, the personality traits of a person. Important is the fact that personality traits are a moderately heritable factor and on the basis of the analysis of several genes, various lifetime outcomes can be predicted. One of the most important pathways influencing personality traits is connected to the dopaminergic system; hence, we decided to analyze the DRD2 PROM. rs1799732, DRD2 rs1076560, DRD2 Tag1D rs1800498, DRD2 Ex8 rs6276, DRD2Tag1B rs1079597 and ANKK1 Tag1A rs180049. The research group included 258 male athletes (mean age = 26.02; SD = 8.30), whereas the control group was 284 healthy male volunteers matched for age (mean age = 22.89; SD = 4.78), both of Caucasian origin and without history of substance dependency or psychosis. Genomic DNA was extracted from venous blood using standard procedures. Genotyping was conducted with the real-time PCR method. Differences in the frequency of the DRD2Tag1B rs1079597 gene polymorphism were found between people practicing combat sports and the control group, and the DRD2 PROM. rs1799732, DRD2 rs1076560, DRD2 Tag1D rs1800498, DRD2 Ex8 rs6276, DRD2Tag1B rs1079597 and ANKK1 Tag1A rs1800497 genotypes and allele frequencies in the studied sample did not differ between the analyzed groups. Hence, we considered these polymorphic places as an interesting area for the further search for unambiguous associations between personality traits and attitude towards physical effort.

Evidence for Protein-Protein Interaction between Dopamine Receptors and the G Protein-Coupled Receptor 143

Protein-protein interactions between G protein-coupled receptors (GPCRs) can augment their functionality and increase the repertoire of signaling pathways they regulate. New therapeutics designed to modulate such interactions may allow for targeting of a specific GPCR activity, thus reducing potential for side effects. Dopamine receptor (DR) heteromers are promising candidates for targeted therapy of neurological conditions such as Parkinson's disease since current treatments can have severe side effects. To facilitate development of such therapies, it is necessary to identify the various DR binding partners. We report here a new interaction partner for DRD₂ and DRD₃, the orphan receptor G protein-coupled receptor 143 (GPR143), an atypical GPCR that plays multiple roles in pigment cells and is expressed in several regions of the brain. We previously demonstrated that the DRD₂/ DRD₃ antagonist pimozide also modulates GPR143 activity. Using confocal microscopy and two FRET methods, we observed that the DRs and GPR143 colocalize and interact at intracellular membranes. Furthermore, co-expression of wildtype GPR143 resulted in a 57% and 67% decrease in DRD₂ and DRD₃ activity, respectively, as determined by β-Arrestin recruitment assay. GPR143-DR dimerization may negatively modulate DR activity by changing affinity for dopamine or delaying delivery of the DRs to the plasma membrane.

Dysregulation of Synaptic Signaling Genes Is Involved in Biology of Uterine Leiomyoma

Uterine leiomyomas are tumors, which are hormone driven and originate from the smooth muscle layer of the uterine wall. In addition to known genes in leiomyoma pathogenesis, recent approaches also highlight epigenetic malfunctions as an important mechanism of gene dysregulation. RNA sequencing raw data from pair-matched normal myometrium and fibroid tumors from two independent studies were used as discovery and validation sets and reanalyzed. RNA extracted from normal myometrium and fibroid tumors from 58 Slovenian patients was used as independent confirmation of most significant differentially expressed genes. Subsequently, GWA data from leiomyoma patients were used in order to identify genetic variants at epigenetic marks. Gene Ontology analysis of the overlap of two independent RNA-seq analyses showed that NPTX1, NPTX2, CHRM2, DRD2 and CACNA1A were listed as significant for several enriched GO terms. All five genes were subsequently confirmed in the independent Slovenian cohort. Additional integration and functional analysis showed that genetic variants in these five gene regions are listed at a chromatin structure and state, predicting promoters, enhancers, DNase hypersensitivity and altered transcription factor binding sites. We identified a unique subgroup of dysregulated synaptic signaling genes involved in the biology and pathogenesis of leiomyomas, adding to the complexity of tumor biology.

Candidate Genes Encoding Dopamine Receptors as Predictors of the Risk of Antipsychotic-Induced Parkinsonism and Tardive Dyskinesia in Schizophrenic Patients

(1) Introduction: Extrapyramidal disorders form the so-called extrapyramidal syndrome (EPS), which is characterized by the occurrence of motor disorders as a result of damage to the basal ganglia and the subcortical-thalamic connections. Often, this syndrome develops while taking medications, in particular antipsychotics (APs). (2) Purpose: To review studies of candidate genes encoding dopamine receptors as genetic predictors of development of AP-induced parkinsonism (AIP) and AP-induced tardive dyskinesia (AITD) in patients with schizophrenia. (3) Materials and Methods: A search was carried out for publications of PubMed, Web of Science, Springer, and e-Library databases by keywords and their combinations over the last 10 years. In addition, the review includes earlier publications of historical interest. Despite extensive searches of these commonly used databases and search terms, it cannot be ruled out that some publications were possibly missed. (4) Results: The review considers candidate genes encoding dopamine receptors involved in pharmacodynamics, including genes DRD1, DRD2, DRD3, and DRD4. We analyzed 18 genome-wide studies examining 37 genetic variations, including single nucleotide variants (SNVs)/polymorphisms of four candidate genes involved in the development of AIP and AITD in patients with schizophrenia. Among such a set of obtained results, only 14 positive associations were revealed: rs1799732 (141CIns/Del), rs1800497 (C/T), rs6275 (C/T), rs6275 (C/T) DRD2; rs167771 (G/A) DRD3 with AIP and rs4532 (A/G) DRD1, rs6277 (C/T), rs6275 (C/T), rs1800497 (C/T), rs1079597 (A/G), rs1799732 (141CIns/Del), rs1045280 (C/G) DRD2, rs6280 (C/T), rs905568 (C/G) DRD3 with AITD. However, at present, it should be recognized that there is no final or unique decision on the leading role of any particular SNVs/polymorphisms in the development of AIP and AITD. (5) Conclusion: Disclosure of genetic predictors of the development of AIP and AITD, as the most common neurological adverse drug reactions (ADRs) in the treatment of patients with psychiatric disorders, may provide a key to the development of a strategy for personalized prevention and treatment of the considered complication of AP therapy for schizophrenia in real clinical practice.

De novo design with deep generative models based on 3D similarity scoring

We have demonstrated the utility of a 3D shape and pharmacophore similarity scoring component in molecular design with a deep generative model trained with reinforcement learning. Using Dopamine receptor type 2 (DRD2) as an example and its antagonist haloperidol 1 as a starting point in a ligand based design context, we have shown in a retrospective study that a 3D similarity enabled generative model can discover new leads in the absence of any other information. It can be efficiently used for scaffold hopping and generation of novel series. 3D similarity based models were compared against 2D QSAR based, indicating a significant degree of orthogonality of the generated outputs and with the former having a more diverse output. In addition, when the two scoring components are combined together for training of the generative model, it results in more efficient exploration of desirable chemical space compared to the individual components.

Overexpression of dopamine receptor D2 promotes colorectal cancer progression by activating the β-catenin/ZEB1 axis

Colorectal cancer (CRC) is a recurring cancer that is often resistant to conventional therapies and therefore requires the development of molecular-based therapeutic approaches. Dopamine receptor D2 (DRD2) is associated with the growth of many types of tumors, but its oncogenic role in CRC is unclear. Here, we observed that elevated DRD2 expression was associated with a poor survival rate among patients with CRC. Depletion of DRD2 suppressed CRC cell growth and motility by downregulating β-catenin/ZEB signaling in vitro and in vivo, whereas overexpression of DRD2 promoted CRC cell progression. Inhibition of DRD2 by the antagonist pimozide inhibited tumor growth and lymph node metastasis in vivo and enhanced the cytotoxic effects of conventional agents in vitro. Taken together, our findings indicate that targeting the DRD2/β-catenin/ZEB1 signaling axis is a potentially promising therapeutic strategy for patients with CRC.

Exploring pharmacogenetic variation in a Bulgarian psychiatric cohort

INTRODUCTION

Pharmacogenetics in psychiatry is currently gaining momentum. The efficiency of antipsychotic therapy is often limited by the lack of response and the presence of side effects. Pharmacogenetic variation is probably one of the causative factors for the observed interindividual differences in the response to and the side effects of antipsychotics, which could be addressed and whose negative effects could be avoided or mitigated.

AIM

The present study aimed to conduct a comprehensive analysis of the frequency of DRD2 rs1799732, COMT rs4680, MC4R rs489693, and HTR2C rs3813929 in Bulgarian psychiatric patients.

MATERIALS AND METHODS

The frequency of genotypes and the alleles of variants DRD2 rs1799732, COMT rs4680, MC4R rs489693, and HTR2C rs3813929 were studied in a cohort of 515 Bulgarian psychiatric patients using the polymerase chain reaction (PCR) method.

RESULTS

We found no significant difference between our cohort and the dataset of the 1000 Genomes Project. Moreover, we found that 433 out of 515 patients carried at least one, and 191 out of 515 carried at least two variants which, based on multiple scientific sources with consistent findings, could potentially alter the expected response rate, time to respond and/or risk of side effects to antipsychotic medications.

CONCLUSIONS

Considering the consistent data about the frequency of these pharmacogenetic variants, testing these genetic variants may prove useful in clinical practice. Further studies regarding the clinical interpretation and frequency distribution in larger cohorts and different populations are warranted.

Clinical and Genetic Analysis of Psychosis in Parkinson's Disease

BACKGROUND

Recent studies explored polymorphisms of multiple genes as contributing to genetic susceptibility to psychosis in Parkinson's disease (PDP).

OBJECTIVE

We aimed to examine the association of seven selected polymorphisms of genes related to dopamine pathways with PDP development. At the same time, demographic and clinical correlates of PDP were assessed.

METHODS

PD patients (n = 234), treated with levodopa for at least two years, were genotyped for the rs4680 in COMT, rs6277, rs1076560, and rs2283265 in DRD2, and rs1800497 and rs2734849 polymorphisms in ANKK1 genes. Also, variable number of tandem repeats polymorphism in the DAT gene was examined. Each patient underwent comprehensive neurological examination, assessment of psychosis, as defined by the NINDS/NIMH criteria, as well as screening of depression, anxiety, and cognitive status.

RESULTS

Diagnostic criteria for PDP were met by 101 (43.2%) patients. They had longer disease duration, were taking higher doses of dopaminergic agents, and had higher scores of the motor and non-motor scales than the non-PDP group. Multivariate regression analysis revealed LEDD≥900 mg, Unified Parkinson's Disease Rating Scale III part score, the Hamilton Depression Rating Scale score≥7, the Hamilton Anxiety Rating Scale score >  14,and GG homozygotes of rs2734849 ANKK1 as independent predictors of the onset of PDP.

CONCLUSION

Besides previous exposure to dopaminergic drugs, impairment of motor status, depression and anxiety, as well-established clinical risk factors for the development of PDP, GG rs2734849 ANKK1 could also be a contributing factor, which requires addressing by future longitudinal studies.

Total barley maiya alkaloids inhibit prolactin secretion by acting on dopamine D2 receptor and protein kinase A targets

ETHNOPHARMACOLOGICAL RELEVANCE

Barley maiya from gramineous plants (Hordeum vulgare L.) is obtained from ripe fruits through germination and drying. It is often used to treat diseases associated with high prolactin levels.

OBJECTIVE

To investigate the anti-hyperprolactinemia (anti-HPRL) mechanisms of total barley maiya alkaloids (TBMA) and hordenine.

METHODS

This experiment included 9 groups: Normal group, TBMA group, hordenine group, TBMA + haloperidol group, TBMA + forskolin group, TBMA + 8-bromo-cAMP group, hordenine + haloperidol group, hordenine + forskolin group, and hordenine + 8-bromo-cAMP group. The prolactin (PRL) concentration in the supernatant and the total cAMP concentration in the cells were detected by ELISA. The expression levels of PRL, dopamine D2 receptor (DRD2) and cAMP/PKA/CREB protein were measured by Western Blot.

RESULTS

In the TBMA group and the hordenine group, the PRL level in MMQ cells was significantly decreased, but in GH3 cells there was no change. DRD2 expression level was markedly increased, cAMP concentration was decreased, and the activity of PKA and CREB declined in MMQ cells. Compared with the TBMA group, there was a significant decrease of DRD2 expression level, a remarkable increase of PRL secretion and an increase of cAMP/PKA/CREB expression in MMQ cells within the TBMA + haloperidol group. Compared with the forskolin group, there was no significant change in PRL secretion and cAMP/PKA/CREB expression level in MMQ cells within the TBMA + forskolin group. There was a decrease in PRL secretion and cAMP/PKA/CREB expression level in MMQ cells within the TBMA + 8-bromo-cAMP group compared with the 8-bromo-cAMP group. Compared with the hordenine group, DRD2 expression level was significantly decreased, PRL secretion was markedly increased, and cAMP/PKA/CREB expression level was increased in MMQ cells within the hordenine + haloperidol group. There was no significant change in PRL secretion and cAMP/PKA/CREB expression level in MMQ cells within the hordenine + forskolin group compared with the forskolin group and within the hordenine + 8-bromo-cAMP group compared with the 8-bromo-cAMP group.

CONCLUSION

TBMA and hordenine can both play an anti-HPRL role via DRD2, and TBMA can also act on PKA targets to exert its anti-HPRL effect. TBMA and hordenine may be potential treatment strategies for HPRL.

Dopamine and ghrelin receptor co-expression and interaction in the spinal defecation centers

BACKGROUND

Dopamine receptor 2 (DRD2) and ghrelin receptor (GHSR1a) agonists both stimulate defecation by actions at the lumbosacral defecation center. Dopamine is in nerve terminals surrounding autonomic neurons of the defecation center, whereas ghrelin is not present in the spinal cord. Dopamine at D2 receptors generally inhibits neurons, but at the defecation center, its effect is excitatory.

METHODS

In vivo recording of defecation and colorectal propulsion was used to investigate interaction between DRD2 and GHSR1a. Localization studies were used to determine sites of receptor expression in rat and human spinal cord.

KEY RESULTS

Dopamine, and the DRD2 agonist, quinpirole, directly applied to the lumbosacral cord, caused defecation. The effect of intrathecal dopamine was inhibited by the GHSR1a antagonist, YIL781, given systemically, but YIL781 was not an antagonist at DRD2. The DRD2 agonist, pramipexole, administered systemically caused colorectal propulsion that was prevented when the pelvic nerves were cut. Drd2 and Ghsr were expressed together in autonomic preganglionic neurons at the level of the defecation centers in rat and human. Behaviorally induced defecation (caused by water avoidance stress) was reduced by the DRD2 antagonist, sulpiride. We had previously shown it is reduced by YIL781.

CONCLUSIONS AND INFERENCES

Our observations imply that dopamine is a transmitter of the defecation pathways whose actions are exerted through interacting dopamine (D2) and ghrelin receptors on lumbosacral autonomic neurons that project to the colorectum. The results explain the excitation by dopamine agonists and the conservation of GHSR1a in the absence of ghrelin.

Epidermal growth factor receptor as a molecular determinant of glioblastoma response to dopamine receptor D2 inhibitors

BACKGROUND

There are ongoing clinical trials exploring the efficacy of dopamine receptor D2 (DRD2) inhibition against glioblastomas, the most common primary brain tumor. Here we examine potential molecular determinants of this efficacy.

METHODS

The Cancer Genome Atlas glioblastoma database and other published mRNA profiles were used to analyze the DRD2 and epidermal growth factor receptor (EGFR) expression pattern. In vitro and in vivo responses to DRD2 inhibitors were determined using patient-derived xenograft (PDX) glioblastoma models. Immunohistochemical studies were performed on clinically annotated glioblastoma samples derived from patients treated with ONC201.

RESULTS

Analysis of clinical glioblastoma specimens derived from independent patient cohorts revealed an inverse correlation between EGFR and DRD2 mRNA expression, with implication that signaling mediated by these proteins shares overlapping functions. In independent panels of PDX glioblastoma lines, high EGFR expression was associated with poor in vitro and in vivo response to DRD2 inhibitors, including haloperidol and ONC201. Moreover, ectopic expression of a constitutively active EGFR, variant (v)III, suppressed glioblastoma sensitivity to ONC201. DRD2 expression positively correlated with expression of rate-limiting enzymes for dopamine synthesis as well as dopamine secretion, suggesting contribution of autocrine DRD2 signaling. Analysis of specimens from patients treated with ONC201 (n = 15) showed an inverse correlation between the intensity of EGFR staining and clinical response. The median overall survival for patients with high and low EGFR staining was 162 and 373 days, respectively (0.037).

CONCLUSIONS

High EGFR expression is a determinant of poor glioblastoma response to DRD2. This finding should inform future clinical trial designs.

Detection of altered methylation of MB-COMT promotor and DRD2 gene in cannabinoid or synthetic cannabinoid use disorder regarding gene variants and clinical parameters

This study aims to investigate the association between cannabinoid use disorder (CUD) or synthetic cannabinoid use disorder (SCUD) and methylation status of MB-COMT (membrane-bound catechol-O-methyltransferase) promotor or DRD2 gene considering gene variants and clinical parameters. Based on the DSM-5 criteria, 218 CUD/SCUD patients' diagnoses were confirmed with a positive urine test, and a control group consisting of 102 participants without substance use disorders was included. Methylation-specific PCR was used to identify the methylation of the MB-COMT promotor and DRD2 gene. DRD2-141C Ins/Del and COMT Val158Met gene variants were evaluated by using PCR-RFLP. When the DRD2 and MB-COMT promoter methylation of CUD/SCUD patients were compared with the control group, there was a significant difference between the MB-COMT promoter methylation status of the two groups. When comparing DRD2 gene methylation due to clinical parameters and DRD2 genotype distribution in patients, the methylation status was significantly different between the groups due to the family history. Again, comparing the MB-COMT promotor methylation due to the COMT Val158Met genotype distribution and clinical parameters in patients, the MB-COMT promoter methylation status was significantly different between the groups due to the presence of alcohol usage. In summary, whereas the MB-COMT promoter methylation may be associated with the CUD/SCUD, the methylation of the DRD2 gene was not related to CUD/SCUD.

Tumor suppressor DRD2 facilitates M1 macrophages and restricts NF-κB signaling to trigger pyroptosis in breast cancer

Rationale: Breast cancer (BrCa) is the most common cancer worldwide, and the 5-year relative survival rate has declined in patients diagnosed at stage IV. Advanced BrCa is considered as incurable, which still lack effective treatment strategies. Identifying and characterizing new tumor suppression genes is important to establish effective prognostic biomarkers or therapeutic targets for late-stage BrCa.

Methods: RNA-seq was applied in BrCa tissues and normal breast tissues. Through analyzing differentially expressed genes, DRD2 was selected for further analysis. And expression and promoter methylation status of DRD2 were also determined. DRD2 functions were analyzed by various cell biology assays in vitro. Subcutaneous tumor model was used to explore DRD2 effects in vivo. A co-cultivated system was constructed to investigate interactions of DRD2 and macrophages in vitro. WB, IHC, IF, TUNEL, qRT-PCR, Co-IP, Antibody Array, and Mass Spectrum analysis were further applied to determine the detailed mechanism.

Results: In BrCa, DRD2 was found to be downregulated due to promoter methylation. Higher expression of DRD2 positively correlated with longer survival times especially in HER2-positive patients. DRD2 also promoted BrCa cells sensitivity to Paclitaxel. Ectopic expression of DRD2 significantly inhibited BrCa tumorigenesis. DRD2 also induced apoptosis as well as necroptosis in vitro and in vivo. DRD2 restricted NF-κB signaling pathway activation through interacting with β-arrestin2, DDX5 and eEF1A2. Interestingly, DRD2 also regulated microenvironment as it facilitated M1 polarization of macrophages, and triggered GSDME-executed pyroptosis.

Conclusion: Collectively, this study novelly manifests the role of DRD2 in suppressing BrCa tumorigenesis, predicting prognosis and treatment response. And this study further reveals the critical role of DRD2 in educating M1 macrophages, restricting NF-κB signaling pathway and triggering different processes of programmed cell death in BrCa. Taking together, those findings represent a predictive and therapeutic target for BrCa.