Genes involved in stress response influence lithium efficacy in bipolar patients

Lithium Treatment Increases FKBP5 Protein but Not mRNA Expression in the Pituitary Gland of Depressive-like Rats

Background: Depression is a common psychiatric disorder that may be caused by dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. The glucocorticoid receptor (GR) plays a significant role in regulating this axis. One negative regulator of GR action, previously associated with depressive behavior, is the overexpression of FK506-binding protein 5 (FKBP5), which may be regulated by microRNAs, including miR-511-5p. Objectives: In a rat model of depression, we aimed to investigate the expression of Fkbp5 and its regulator, miRNA-511-5p, during short- and long-term lithium treatment in four brain regions: the hypothalamus, hippocampus, pituitary, and frontal cortex. Methods: We used a rat model of depression induced by chronic mild stress (CMS) to assess if short- and long-term lithium treatment (7 and 42 days) influences Fkbp5 expression in the brain. We also assessed the effects of lithium treatment on the blood levels of corticosterone in CMS-exposed rats as compared to control groups. The changes in the expression of Fkbp5 were assessed by qPCR and Western blot. The expression of rno-miR-511-5p was assessed using qPCR. Statistical analysis was conducted in GraphPad Prism 9. Results: We found that long-term lithium treatment increased the expression of the FKBP5 protein in the pituitary gland in the lithium-treated rats compared to the control group. We also observed significant changes in Fkbp5 mRNA levels between CMS-exposed rats compared to the control animals, without significant changes in mRNA levels observed during short- and long-term lithium treatment in any brain region. We found no expression of rno-miR-511-5p in the analyzed brain regions. The corticosterone levels were significantly higher in CMS-exposed rats compared to the control, with no significant changes found between lithium-treated and control rats. Conclusions: FKBP5 protein expression in the brain may be regulated by long-term lithium treatment, thus affecting GR signaling in the rat depression model.

The Mechanisms of Lithium Action: The Old and New Findings

Despite lithium's presence in modern psychiatry for three-quarters of a century, the mechanisms of its therapeutic action have not been fully elucidated. This article presents the evolution of the views on these mechanisms, and both the old and new findings are discussed. Among the old mechanisms, lithium's effect on the purinergic system; electrolyte metabolism; membrane transport; and second messenger systems, namely, cyclic nucleotide and phosphatidylinositol (PI), glycogen synthase kinase-3beta (GSK-3β), brain-derived neurotrophic factor, and neurotransmitters, are discussed. The new data were obtained from in vitro studies, molecular biology, and genetic research. They showed the effects of lithium on the immune system, biological rhythms, telomere functions, and mitochondria. In this article, each lithium mechanism is considered in the light of its association with the pathogenesis of bipolar disorder or/and as a marker of the lithium response. Although not exhaustive, this review elucidates the multiple potential mechanisms of lithium action. It was also observed that many seemingly "old" mechanisms have experienced a resurgence in research conducted during the 21st century. Additionally, many studies converged on the previously postulated mechanisms of lithium inhibiting GSK-3β and PI.

The implication of ADRA2A and AVPRIB gene variants in the aetiology of stress-related bipolar disorder

OBJECTIVE

Bipolar disorder is a complex and severe mental illness characterised by manic and depressive episodes that can be triggered and exacerbated by psychosocial, environmental, and biological stressors. Genetic variations are a risk factor for bipolar disorder. However, the identification of the exact gene variants and genotypes remains complex. This study, therefore, aims to identify the potential association between genotypes of analysed single nucleotide polymorphisms and the presence of a stressor in bipolar disorder patients.

METHOD

We analysed 114 single nucleotide polymorphisms (SNPs) from bipolar and stress-related candidate genes in 550 patients with bipolar disorders (60.36 % females and 39.64 % male). We compared SNPs of patients reporting the presence (40.73 %) or absence of stressors (59.27 %) before the first episode using the Persons Chi-square test and Bayes Factor t-test. The genotyping of 114 SNPs was done using TaqMan assays. Statistical analysis was done using Statistica 13.3 software (StatSoft Poland, Krakow, Poland), R programming, and G*Power statistics.

RESULT

We found significant differences in genotype distribution (p < 0.05) in 6 polymorphisms (AVPRIB/rs28536160, FKBP4/rs2968909, ADRA2A/rs3750625, 5HTR2A/rs6311, 5HTR2A/rs6313, and GLCCI1/rs37972) when comparing BD patient with and without stressor with a small effect of d = 0.2. Of these, two gene variants (ADRA2A/rs3750625/AC and AVPRIB/rs28536160/CT) with minor alleles formed an association with the presence of a stressor prior to the disease onset and favoured the alternative hypothesis using Bayes Factor Analysis t-test for hypothesis testing.

CONCLUSION

This study presents a novel association of ADRA2A/rs3750625/AC and AVPR1B/rs28536160/CT gene variants in stress-related bipolar disorder with the AC genotype of ADRA2A/rs3750625 constituting a risk genotype and CT of AVPR1B/rs28536160 constituting a protective genotype. However, further functional analysis is required to fully understand their clinical and biological significance and interaction.

Effectiveness of ultra-long-term lithium treatment: relevant factors and case series

BACKGROUND

The phenomenon of preventing the recurrences of mood disorders by the long-term lithium administration was discovered sixty years ago. Such a property of lithium has been unequivocally confirmed in subsequent years, and the procedure makes nowadays the gold standard for the pharmacological prophylaxis of bipolar disorder (BD). The efficacy of lithium prophylaxis surpasses other mood stabilizers, and the drug has the longest record as far as the duration of its administration is concerned. The continuation of lithium administration in case of good response could be a lifetime and last for several decades. The stability of lithium prophylactic efficacy in most patients is pretty steady. However, resuming lithium after its discontinuation may, in some patients, be less efficient.

MAIN BODY

In the article, the clinical and biological factors connected with the prophylactic efficacy of long-term lithium administration are listed. Next, the adverse and beneficial side effects of such longitudinal treatment are presented. The main problems of long-term lithium therapy, which could make an obstacle to lithium continuation, are connected with lithium's adverse effects on the kidney and, to lesser extent, on thyroid and parathyroid functions. In the paper, the management of these adversities is proposed. Finally, the case reports of three patients who have completed 50 years of lithium therapy are described.

CONCLUSIONS

The authors of the paper reckon that in the case of good response, lithium can be given indefinitely. Given the appropriate candidates for such therapy and successful management of the adverse effects, ultra-long term lithium therapy is possible and beneficial for such patients.

Role of FKBP5 and its genetic mutations in stress-induced psychiatric disorders: an opportunity for drug discovery

Stress-induced mental health disorders are affecting many people around the world. However, effective drug therapy for curing psychiatric diseases does not occur sufficiently. Many neurotransmitters, hormones, and mechanisms are essential in regulating the body's stress response. One of the most critical components of the stress response system is the hypothalamus-pituitary-adrenal (HPA) axis. The FKBP prolyl isomerase 51 (FKBP51) protein is one of the main negative regulators of the HPA axis. FKBP51 negatively regulates the cortisol effects (the end product of the HPA axis) by inhibiting the interaction between glucocorticoid receptors (GRs) and cortisol, causing reduced transcription of downstream cortisol molecules. By regulating cortisol effects, the FKBP51 protein can indirectly regulate the sensitivity of the HPA axis to stressors. Previous studies have indicated the influence of FKBP5 gene mutations and epigenetic changes in different psychiatric diseases and drug responses and recommended the FKBP51 protein as a drug target and a biomarker for psychological disorders. In this review, we attempted to discuss the effects of the FKBP5 gene, its mutations on different psychiatric diseases, and drugs affecting the FKBP5 gene.

Lack of association of FKBP5 SNPs and haplotypes with susceptibility and treatment response phenotypes in Han Chinese with major depressive disorder: A pilot case-control study (STROBE)

The identification of single-nucleotide polymorphisms (SNPs) in genes putatively related to pathophysiological processes in major depressive disorder (MDD) might improve both diagnosis and personalized treatment strategies eventually leading to more effective interventions. Considering the important role of the glucocorticoid receptor and the related FK506 binding protein 51 (FKBP51) in the pathophysiology of MDD, we aimed to investigate putative associations between variants of FKBP5, the coding gene of FKBP51, with antidepressant treatment resistance and MDD susceptibility.Nine common SNPs of the FKBP5 gene prioritized based on location and, putative or known functions were genotyped in Han Chinese population, including MDD patients with or without antidepressant-treatment resistance and healthy controls. Associations of FKBP5 SNPs with MDD susceptibility and treatment response were examined in the whole group of MDD patients, as well as in subgroups stratified by antidepressant treatment resistance, compared with healthy controls.In total, 181 Han Chinese patients with MDD and 80 healthy controls were recruited. No significant SNP or haplotype associations were observed in the whole patient group. There were nominal significant differences both for the haplotype block with SNPs in strong LD (r2 > 0.8, P = .040) and haplotype block with SNPs in moderate LD (r2 > 0.1, P = .017) between the haplotype distributions of patients with antidepressant treatment resistance (n = 81) and healthy controls, but both significances did not survive multiple testing correction. Furthermore, no specific haplotype could be observed causing a significant difference in any combination between all comparisons.No associations were observed of FKBP5 variants with MDD or antidepressant treatment response. The lack of associations might be due to the relatively small sample size of this study (power ranged from 0.100 to 0.752). A follow-up study will need larger, better phenotyped, and more homogeneous samples to draw a definitive conclusion regarding the involvement of this gene in MDD.

Genes involved in glucocorticoid receptor signalling affect susceptibility to mood disorders

OBJECTIVES

In mood disorders chronic stress contributes to decreased glucocorticoid receptor signalling in the brain and resistance in the periphery. We hypothesised that aberrant glucocorticoid receptor function may result from genetic predisposition and that decreased GR signalling in the brain correlates with the expression of genes regulating GR complex formation.

METHODS

We performed the association analysis of 698 patients: 490 patients with bipolar disorder and 208 patients with major depressive disorder and 564 control subjects. We genotyped 11 variants using TaqMan assays. Gene expression in the brain tissue was done in male Wistar rats after chronic mild stress protocol. The SRSF5 serum concentration was performed using ELISA. Data were analysed in Statistica and GraphPad.

RESULTS

We found an association of STIP1 and SRSF5 variants with major depressive disorder and BAG1 variant with bipolar disorder. Gene expression analysis in a rat model of depression confirmed significant changes in the expression of SRSF5, BAG1, and FKBP4 in the brain. For SRSF5, we observed significantly increased expression in the serum of depressed females and male rats exposed to chronic stress.

CONCLUSIONS

Our results indicate the involvement of genes associated with GR function, SRSF5, BAG1, and FKBP4 with susceptibility to mood disorders.

Lithium treatment in the era of personalized medicine

In 1949, an Australian psychiatrist, John Cade, reported on the antimanic efficacy of lithium carbonate, which is regarded as an introduction of lithium into contemporary psychiatry. Since the 1960s, lithium has been a precursor of mood stabilizers and has become first-choice drug for the prevention of affective episodes in mood disorders. For nearly four decades, lithium has also been used for the augmentation of antidepressant drugs in treatment-resistant depression. The knowledge of clinical and biological factors connected with the capability of long-term lithium treatment to prevent manic and depressive recurrences makes an important element of the personalized medicine of mood disorders. Excellent prophylactic lithium responders can be characterized by distinct mood episodes, with full remissions between them, the absence of other psychiatric morbidity, and the family history of bipolar illness. In recent years, many other clinical and biological factors connected with such a response have been identified, helping to select the best candidates for lithium prophylaxis. The antisuicidal effect of lithium during its long-term administration has been demonstrated and should also be taken into account as the element of personalized medicine for the pharmacological prophylaxis of patients with mood disorders. Several studies pertaining to personalized medicine were also dedicated to lithium treatment of acute mood episodes. Lithium still has a value in the treatment of mania and bipolar depression. However, it seems that the more important indication would be the augmentation of antidepressant drugs in treatment-resistant depression. The factors connected with the efficacy of lithium in these conditions are reviewed.

Male-specific association of the 2p25 region with suicide attempt in bipolar disorder

We previously conducted a genome-wide association study (GWAS) of attempted suicide within bipolar disorder, which implicated common variation in the 2p25 region primarily in males. The top association signal from our GWAS occurred in an intergenic region of 2p25 (p = 5.07 × 10^-8) and was supported by two independent studies. In the current study, to better characterize the association of the 2p25 region with attempted suicide, we sequenced the entire 350kb 2p25 region in 476 bipolar suicide attempters and 473 bipolar non-attempters using targeted next-generation sequencing. This fine-mapping project identified 4,681 variants in the 2p25 region. We performed both gene-level and individual-variant tests on our sequencing results and identified 375 variants which were nominally significant (p < 0.05) and three common variants that were significantly associated with attempted suicide in males (corrected p = 0.035, odds ratio (OR) = 2.13). These three variants are in strong linkage disequilibrium with the top variant from our GWAS. Our top five variants are also predicted expression quantitative trait loci (eQTL) for three genes in the 2p25 region based on publicly available brain expression databases. Our sequencing and eQTL data implicate these three genes - SH3YL1, ACP1, and FAM150B - and three additional pathways - androgen receptor, Wnt signaling, and glutamatergic/GABAergic signaling - in the association of the 2p25 region with suicide. The current study provides additional support for an association of the 2p25 region with attempted suicide in males and identifies several candidate genes and pathways that warrant further investigation to understand their role in suicidal behavior.