ABCB1 and DRD3 polymorphism as a response predicting biomarker and tool for pharmacogenetically guided clozapine dosing in Asian Indian treatment resistant schizophrenia patients

Epistasis in neurotransmitter receptors linked to posttraumatic stress disorder and major depressive disorder comorbidity in traumatized Chinese

Background

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) comorbidity occurs through exposure to trauma with genetic susceptibility. Neuropeptide-Y (NPY) and dopamine are neurotransmitters associated with anxiety and stress-related psychiatry through receptors. We attempted to explore the genetic association between two neurotransmitter receptor systems and the PTSD-MDD comorbidity.

Methods

Four groups were identified using latent profile analysis (LPA) to examine the patterns of PTSD and MDD comorbidity among survivors exposed to earthquake-related trauma: low symptoms, predominantly depression, predominantly PTSD, and PTSD-MDD comorbidity. NPY2R (rs4425326), NPY5R (rs11724320), DRD2 (rs1079597), and DRD3 (rs6280) were genotyped from 1,140 Chinese participants exposed to earthquake-related trauma. Main, gene-environment interaction (G × E), and gene-gene interaction (G × G) effects for low symptoms, predominantly depression, and predominantly PTSD were tested using a multinomial logistic model with PTSD-MDD comorbidity as a reference.

Results

The results demonstrated that compared to PTSD-MDD comorbidity, epistasis (G × G) NPY2R-DRD2 (rs4425326 × rs1079597) affects low symptoms (β = -0.66, OR = 0.52 [95% CI: 0.32-0.84], p = 0.008, pperm = 0.008) and predominantly PTSD (β = -0.56, OR = 0.57 [95% CI: 0.34-0.97], p = 0.037, pperm = 0.039), while NPY2R-DRD3 (rs4425326 × rs6280) impacts low symptoms (β = 0.82, OR = 2.27 [95% CI: 1.26-4.10], p = 0.006, pperm = 0.005) and predominantly depression (β = 1.08, R = 2.95 [95% CI: 1.55-5.62], p = 0.001, pperm = 0.001). The two G × G effects are independent.

Conclusion

NPY and dopamine receptor genes are related to the genetic etiology of PTSD-MDD comorbidity, whose specific mechanisms can be studied at multiple levels.

Current insights into the oncogenic roles of lncRNA LINC00355

Long noncoding RNAs (lncRNAs) are a class of nonprotein-coding transcripts that are longer than 200 nucleotides. LINC00355 is a lncRNA located on chromosome 13q21.31 and is consistently upregulated in various cancers. It regulates the expression of downstream genes at both transcriptional and posttranscriptional levels, including eight microRNAs (miR-15a-5p, miR-34b-5p, miR-424-5p, miR-1225, miR-217-5p, miR-6777-3p, miR-195, and miR-466) and three protein-coding genes (ITGA2, RAD18, and UBE3C). LINC00355 plays a role in regulating various biological processes such as cell cycle progression, proliferation, apoptosis, epithelial-mesenchymal transition, invasion, and metastasis of cancer cells. It is involved in the regulation of the Wnt/β-catenin signaling pathway and p53 signaling pathway. Upregulation of LINC00355 has been identified as a high-risk factor in cancer patients and its increased expression is associated with poorer overall survival, recurrence-free survival, and disease-free survival. LINC00355 upregulation has been linked to several unfavorable clinical characteristics, including advanced tumor node metastasis and World Health Organization stages, reduced Karnofsky Performance Scale scores, increased tumor size, greater depth of invasion, and more extensive lymph node metastasis. LINC00355 induces chemotherapy resistance in cancer cells by regulating five downstream genes, namely HMGA2, ABCB1, ITGA2, WNT10B, and CCNE1 genes. In summary, LINC00355 is a potential oncogene with great potential as a diagnostic marker and therapeutic target for cancer.

Prediction of treatment response to antipsychotic drugs for precision medicine approach to schizophrenia: randomized trials and multiomics analysis

BACKGROUND

Choosing the appropriate antipsychotic drug (APD) treatment for patients with schizophrenia (SCZ) can be challenging, as the treatment response to APD is highly variable and difficult to predict due to the lack of effective biomarkers. Previous studies have indicated the association between treatment response and genetic and epigenetic factors, but no effective biomarkers have been identified. Hence, further research is imperative to enhance precision medicine in SCZ treatment.

METHODS

Participants with SCZ were recruited from two randomized trials. The discovery cohort was recruited from the CAPOC trial (n = 2307) involved 6 weeks of treatment and equally randomized the participants to the Olanzapine, Risperidone, Quetiapine, Aripiprazole, Ziprasidone, and Haloperidol/Perphenazine (subsequently equally assigned to one or the other) groups. The external validation cohort was recruited from the CAPEC trial (n = 1379), which involved 8 weeks of treatment and equally randomized the participants to the Olanzapine, Risperidone, and Aripiprazole groups. Additionally, healthy controls (n = 275) from the local community were utilized as a genetic/epigenetic reference. The genetic and epigenetic (DNA methylation) risks of SCZ were assessed using the polygenic risk score (PRS) and polymethylation score, respectively. The study also examined the genetic-epigenetic interactions with treatment response through differential methylation analysis, methylation quantitative trait loci, colocalization, and promoter-anchored chromatin interaction. Machine learning was used to develop a prediction model for treatment response, which was evaluated for accuracy and clinical benefit using the area under curve (AUC) for classification, R² for regression, and decision curve analysis.

RESULTS

Six risk genes for SCZ (LINC01795, DDHD2, SBNO1, KCNG2, SEMA7A, and RUFY1) involved in cortical morphology were identified as having a genetic-epigenetic interaction associated with treatment response. The developed and externally validated prediction model, which incorporated clinical information, PRS, genetic risk score (GRS), and proxy methylation level (proxyDNAm), demonstrated positive benefits for a wide range of patients receiving different APDs, regardless of sex [discovery cohort: AUC = 0.874 (95% CI 0.867-0.881), R² = 0.478; external validation cohort: AUC = 0.851 (95% CI 0.841-0.861), R² = 0.507].

CONCLUSIONS

This study presents a promising precision medicine approach to evaluate treatment response, which has the potential to aid clinicians in making informed decisions about APD treatment for patients with SCZ. Trial registration Chinese Clinical Trial Registry ( https://www.chictr.org.cn/ ), 18. Aug 2009 retrospectively registered: CAPOC-ChiCTR-RNC-09000521 ( https://www.chictr.org.cn/showproj.aspx?proj=9014 ), CAPEC-ChiCTR-RNC-09000522 ( https://www.chictr.org.cn/showproj.aspx?proj=9013 ).

Clozapine research from India: A systematic review

BACKGROUND

Although clozapine is much researched in western literature, a review on Indian research on clozapine published in 2010 reported limited data and need for further research in this area.

AIM

We aimed to conduct a systematic review of research on clozapine from India from 2010 to mid-2022 and also compare the same with research output before 2010.

METHODOLOGY

A systematic various search engines, i.e., PUBMED, Medknow, Hinari and Google Scholar was done using the key words clozapine and India. Published articles with clozapine in the title and having an author from India, published during 2010 to July 2022 were included.

RESULTS

Initial Internet and hand searches yielded 280 articles, out of which 126 articles were excluded due to various reasons and 154 articles, were included for the review. This included 84 case reports, 49 original articles, 11 review articles and 10 letters to the editor as comments. We found an increase in the number of publications during the period of 2010-2022 compared to 1997-2009 in all types of publications. Over the years a significant proportion of the articles focused on various side effects of clozapine, factors associated with response and non-response to clozapine and evaluation of outcomes other than efficacy/effectiveness. However, all the studies were limited to a single centre with no multicentric studies on clozapine.

CONCLUSION

Over the last 12 years or so, there is increase in the number of publications on clozapine. However, there is lack of multicentric studies.

Peripheral biomarkers of treatment-resistant schizophrenia: Genetic, inflammation and stress perspectives

Treatment-resistant schizophrenia (TRS) often results in severe disability and functional impairment. Currently, the diagnosis of TRS is largely exclusionary and emphasizes the improvement of symptoms that may not be detected early and treated according to TRS guideline. As the gold standard, clozapine is the most prescribed selection for TRS. Therefore, how to predict TRS in advance is critical for forming subsequent treatment strategy especially clozapine is used during the early stage of TRS. Although mounting studies have identified certain clinical factors and neuroimaging characteristics associated with treatment response in schizophrenia, the predictors for TRS remain to be explored. Biomarkers, particularly for peripheral biomarkers, show great potential in predicting TRS in view of their predictive validity, noninvasiveness, ease of testing and low cost that would enable their widespread use. Recent evidence supports that the pathogenesis of TRS may be involved in abnormal neurotransmitter systems, inflammation and stress. Due to the heterogeneity of TRS and the lack of consensus in diagnostic criteria, it is difficult to compare extensive results among different studies. Based on the reported neurobiological mechanisms that may be associated with TRS, this paper narratively reviews the updates of peripheral biomarkers of TRS, from genetic and other related perspectives. Although current evidence regarding biomarkers in TRS remains fragmentary, when taken together, it can help to better understand the neurobiological interface of clinical phenotypes and psychiatric symptoms, which will enable individualized prediction and therapy for TRS in the long run.

DRD3 Ser9Gly polymorphism and treatment response to antipsychotics in schizophrenia: A meta-analysis

The association between dopamine D3 receptor (DRD3) Ser9Gly polymorphism and treatment response to antipsychotic drugs (APDs) in schizophrenia (SCZ) has been widely reported with inconsistent results, thus we performed an updated meta-analysis to derive a more precise estimation of the relationship. PubMed, Cochrane Library, Medline, Embase, CNKI, Weipu and Wanfang databases were searched for eligible studies published until March 2022. Odds ratios (ORs) with 95 % confidence intervals (CIs) were used to assess the strength of the associations in four genetic models. A total of 13 studies with 1769 patients were included in this meta-analysis. Our findings suggested that Ser9Gly polymorphism was significantly associated with treatment response to APDs in SCZ in allele model (Ser vs Gly, OR = 0.72, 95 % CI = 0.58-0.89, P = 0.002), recessive model (Ser/Ser vs Ser/Gly + Gly/Gly, OR = 0.55, 95 % CI = 0.36-0.86, P = 0.008) and co-dominant model (Ser/Ser vs Gly/Gly, OR = 0.57, 95 % CI = 0.33-0.99, P = 0.045) in Caucasians, but not in Asians. meta-regression revealed that the associations were not confounded by mean age, male ratio and treatment duration (P > 0.05). In summary, our results indicated the DRD3 Ser9Gly may influence the efficacy of APDs in specific genetic models, of which Ser allele and Ser/Ser genotype contributed to poor treatment response in Caucasians.

Pharmacometabolomics-guided clozapine therapy in treatment resistant schizophrenia: Preliminary exploration of future too near

AIM

To study the association of clozapine pharmacometabolomics and clozapine response in Asian patients with treatment-resistant schizophrenia (TRS).

METHOD

A cross-sectional study was performed on 50 consecutive TRS patients following up in psychiatry department of the tertiary care hospital. Demographic details, response assessment, were collected on the case record form. A blood sample was also collected for trough concentration assessment of drug and its metabolites. Clozapine (CLZ) the parent drug and its two major metabolites - Clozapine N oxide (CNO) and N-Desmethyl clozapine (N-DSMC) levels were assessed using a high-performance liquid chromatography method. Clozapine responders and nonresponders patients were classified based upon Andreasen criteria.

RESULTS

The average trough concentration of CNO, N-DSMC, and CLZ were 123 ± 76.04, 171.93 ± 93.24, 229.27 ± 124.25 ng/ml, respectively. The two patient subgroups did not differ for CLZ, CNO, and N-DSMC concentrations statistically. However, clozapine nonresponse was associated with a higher CLZ/N-DSMC ratio (p = 0.03) and clozapine dose (p = 0.01). The receiver operator characteristic curve showed that the cut-off CLZ/N-DSMC ratio of 1.54 with a sensitivity of 85% and a positive predictive value of 84% for identifying nonresponders.

CONCLUSION

CLZ/N-DSMC ratio and clozapine dose were identified as significant variables for future dose optimization algorithms. Pharmacometabolomics-guided clozapine therapy has the potential to revolutionize TRS management.

Possible pharmacogenetic factors in clozapine treatment failure: a case report

There is still much to learn about the predictors of therapeutic response in psychiatry, but progress is gradually being made and precision psychiatry is an exciting and emerging subspeciality in this field. This is critically important in the treatment of refractory psychotic disorders, where clozapine is the only evidence-based treatment but only about half the patients experience an adequate response. In this case report, we explore the possible biological mechanisms underlying treatment failure and discuss possible ways of improving clinical outcomes. Further work is required to fully understand why some patients fail to respond to the most effective treatment in refractory schizophrenia. Therapeutic drug monitoring together with early pharmacogenetic testing may offer a path for some patients with refractory psychotic symptoms unresponsive to clozapine treatment.