Antidepressant-Like Actions of Inhibitors of Poly(ADP-Ribose) Polymerase in Rodent Models

Oxidatively-induced DNA base damage and base excision repair abnormalities in siblings of individuals with bipolar disorder DNA damage and repair in bipolar disorder

Previous evidence suggests elevated levels of oxidatively-induced DNA damage, particularly 8-hydroxy-2'-deoxyguanosine (8-OH-dG), and abnormalities in the repair of 8-OH-dG by the base excision repair (BER) in bipolar disorder (BD). However, the genetic disposition of these abnormalities remains unknown. In this study, we aimed to investigate the levels of oxidatively-induced DNA damage and BER mechanisms in individuals with BD and their siblings, as compared to healthy controls (HCs). 46 individuals with BD, 41 siblings of individuals with BD, and 51 HCs were included in the study. Liquid chromatography-tandem mass spectrometry was employed to evaluate the levels of 8-OH-dG in urine, which were then normalized based on urine creatinine levels. The real-time-polymerase chain reaction was used to measure the expression levels of 8-oxoguanine DNA glycosylase 1 (OGG1), apurinic/apyrimidinic endonuclease 1 (APE1), poly ADP-ribose polymerase 1 (PARP1), and DNA polymerase beta (POLβ). The levels of 8-OH-dG were found to be elevated in both individuals with BD and their siblings when compared to the HCs. The OGG1 and APE1 expressions were downregulated, while POLβ expressions were upregulated in both the patient and sibling groups compared to the HCs. Age, smoking status, and the number of depressive episodes had an impact on APE1 expression levels in the patient group while body mass index, smoking status, and past psychiatric history had an impact on 8-OH-dG levels in siblings. Both individuals with BD and unaffected siblings presented similar abnormalities regarding oxidatively-induced DNA damage and BER, suggesting a link between abnormalities in DNA damage/BER mechanisms and familial susceptibility to BD. Our findings suggest that targeting the oxidatively-induced DNA damage and BER pathway could offer promising therapeutic strategies for reducing the risk of age-related diseases and comorbidities in individuals with a genetic predisposition to BD.

Research Progress on the Antidepressant Effects of Baicalin and Its Aglycone Baicalein: A Systematic Review of the Biological Mechanisms

Depression is the most prevalent mental disorder, affecting more than 300 million adults worldwide each year, which can lead to serious economic and social problems. Antidepressants are usually the first-line treatment for depression, however, traditional antidepressants on the market have the disadvantage of low remission rates and may cause side effects to patients, therefore, the current focus in the field of depression is to develop novel therapeutic agents with high remission rates and few side effects. In this context, the antidepressant effects of natural compounds have received attention. Baicalin (baicalein-7-O-glucuronide) and its aglycone baicalein (5,6,7-trihydroxyflavone) are flavonoid compounds extracted from the root of Scutellaria baicalensis. Although lacking the support of clinical data, they have been shown to have significantly promising antidepressant activity in many preclinical studies through various rodent models of depression. This paper reviews the antidepressant effects of baicalin and baicalein in experimental animal models, with emphasis on summarizing the molecular mechanisms of their antidepressant effects including regulation of the HPA axis, inhibition of inflammation and oxidative stress, reduction of neuronal apoptosis and promotion of neurogenesis, as well as amelioration of mitochondrial dysfunction. Controlled clinical trials should be conducted in the future to examine the effects of baicalin and baicalein on depression in humans.

Synthesis of Veliparib Prodrugs and Determination of Drug-Release-Dependent PARP-1 Inhibition

Poly(ADP-ribose) polymerase (PARP) plays a key role in repairing DNA damage, and several PARP inhibitors have been approved as treatments in BRCA1/2 mutated breast and ovarian cancers. Mounting evidence also supports their application as neuroprotective agents since PARP overactivation compromises the mitochondrial homeostasis by consumption of NAD⁺ reserves, leading to an increase in reactive oxygen and nitrogen species and a spike in intracellular Ca²⁺ levels. Herein, we present the synthesis and preliminary evaluation of new mitochondria-targeting PARP inhibitor prodrugs of (±)-veliparib, with the goal to advance potential neuroprotective properties without impairing the repair of damaged DNA in the nucleus.

Effect of m-Trifluoromethyl-diphenyl diselenide on the Pain-Depression Dyad Induced by Reserpine: Insights on Oxidative Stress, Apoptotic, and Glucocorticoid Receptor Modulation

Chronic pain and depression often coexist sharing common pathological mechanisms, and available analgesics and antidepressants have demonstrated limited clinical efficacy. Evidence has demonstrated that neuronal oxidative stress, apoptosis, and also glucocorticoid receptor dysregulation facilitate the occurrence and development of both chronic pain and depression. This study evaluated the effect of the organoselenium compound m-trifluoromethyl-diphenyl diselenide [(m-CF₃-PhSe)₂] in the pain-depression comorbidity induced by reserpine. Mice were treated with reserpine 0.5 mg/kg for 3 days (intraperitoneal, once a day), and in the next 2 days, they were treated with (m-CF₃-PhSe)₂ 10 mg/kg (intragastric, once a day). Thirty minutes after the last administration of (m-CF₃-PhSe)₂, mice were subjected to the behavioral testing. (m-CF₃-PhSe)₂ treatment reverted the reserpine-increased thermal hyperalgesia and depressive-like behavior observed in the hot-plate test and forced swimming test, respectively. Reserpine provoked a decrease of crossings and rearings in the open-field test, while (m-CF₃-PhSe)₂ presented a tendency to normalize these parameters. Reserpine and/or (m-CF₃-PhSe)₂ treatments did not alter the locomotor activity of mice observed in the rota-rod test. These effects could be related to modulation of oxidative stress, apoptotic pathway, and glucocorticoid receptors, once (m-CF₃-PhSe)₂ normalized thiobarbituric acid reactive substances and 4-hydroxynonenal modified protein levels, markers of lipoperoxidation, poly(ADP-ribose) polymerase cleaved/total ratio, and glucocorticoid receptor levels increased by reserpine in the hippocampus. Considering that pain-depression dyad is a complex state of difficult treatment, this organoselenium compound could raise as an interesting alternative to treat pain-depression condition.

The adenosine A(2A) receptor agonist CGS 21680 alleviates auditory sensorimotor gating deficits and increases in accumbal CREB in rats neonatally treated with quinpirole

RATIONALE AND OBJECTIVE

The adenosine A(2A) receptor forms a mutually inhibitory heteromer with the dopamine D₂ receptor, and A(2A) agonists decrease D₂ signaling. This study analyzed whether an adenosine A(2A) agonist would alleviate deficits in sensorimotor gating and increases in cyclic-AMP response element binding protein (CREB) in the nucleus accumbens (NAc) in the neonatal quinpirole model of schizophrenia (SZ).

METHODS

Male and female Sprague-Dawley rats were neonatally treated with saline (NS) or quinpirole HCl (NQ; 1 mg/kg) from postnatal days (P) 1-21. Animals were raised to P44 and behaviorally tested on auditory sensorimotor gating as measured through prepulse inhibition (PPI) from P44 to P48. Approximately 15 min before each session, animals were given an ip administration of saline or the adenosine A(2A) agonist CGS 21680 (0.03 or 0.09 mg/kg). One day after PPI was complete on P49, animals were administered a locomotor activity test in the open field after saline or CGS 21680 treatment, respectively. On P50, the nucleus accumbens (NAc) was evaluated for CREB protein.

RESULTS

NQ-treated rats demonstrated a deficit in PPI that was alleviated to control levels by either dose of CGS 21680. The 0.03 mg/kg dose of CGS 21680 increased startle amplitude in males. The 0.09 mg/kg dose of CGS 21680 resulted in an overall decrease in locomotor activity. NQ treatment significantly increased NAc CREB that was attenuated to control levels by either dose of CGS 21680.

CONCLUSIONS

This study revealed that an adenosine A(2A) receptor agonist was effective to alleviate PPI deficits in the NQ model of SZ in both male and female rats.

Rapid and temporary improvement of depression and anxiety observed following niraparib administration: a case report

BACKGROUND

Cancer patients are disproportionately affected by generalized anxiety and major depression. For many, current treatments for these conditions are ineffective. In this case report, we present a serendipitous case of anxiety and depression improvement following administration of the poly (ADP-ribose) polymerase (PARP) inhibitor niraparib.

CASE PRESENTATION

A 61-year old woman with a 20-year history of mild depression developed recurrent ovarian carcinoma and was placed on niraparib for maintenance chemotherapy. With the original onset of ovarian cancer, she experienced an episode of major depression that was resolved with sertraline. After recurrence of ovarian cancer, she experienced a recurrence of major depression and a new onset of generalized anxiety that failed to completely respond to multiple medications. After beginning niraparib therapy the patient noticed a rapid resolution of the symptoms of her anxiety and depression, an effect that was limited to 10-14 days. Due to bone marrow suppression, the patient was taken off and restarted on niraparib several times. Each discontinuation of niraparib resulted in return of her depression and anxiety, while each recontinuation of niraparib resulted in an improvement in her mood and anxiety.

CONCLUSIONS

This case demonstrates rapid and temporary improvement of anxiety and depression following niraparib administration. There is ample preclinical data that PARP signaling may play a role in psychiatric illness. A small amount of indirect data from clinical trials also shows that niraparib may have psychiatric benefits. Further research on PARP inhibition and its potential psychoactive effects is sorely needed.

Increased Axin expression enhances adult hippocampal neurogenesis and exerts an antidepressant effect

Major depressive disorders are emerging health problems that affect millions of people worldwide. However, treatment options and targets for drug development are limited. Impaired adult hippocampal neurogenesis is emerging as a key contributor to the pathology of major depressive disorders. We previously demonstrated that increasing the expression of the multifunctional scaffold protein Axis inhibition protein (Axin) by administration of the small molecule XAV939 enhances embryonic neurogenesis and affects social interaction behaviors. This prompted us to examine whether increasing Axin protein level can enhance adult hippocampal neurogenesis and thus contribute to mood regulation. Here, we report that stabilizing Axin increases adult hippocampal neurogenesis and exerts an antidepressant effect. Specifically, treating adult mice with XAV939 increased the amplification of adult neural progenitor cells and neuron production in the hippocampus under both normal and chronic stress conditions. Furthermore, XAV939 injection in mice ameliorated depression-like behaviors induced by chronic restraint stress. Thus, our study demonstrates that Axin/XAV939 plays an important role in adult hippocampal neurogenesis and provides a potential therapeutic approach for mood-related disorders.