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European Archives of Psychiatry and... Oct 2023There is need for novel fast acting treatment options in affective disorders. 3α-reduced neurosteroids such as allopregnanolone are powerful positive allosteric... (Review)
Review
There is need for novel fast acting treatment options in affective disorders. 3α-reduced neurosteroids such as allopregnanolone are powerful positive allosteric modulators of GABA receptors and target also extrasynaptic receptors. Their synthesis is mediated by the translocator protein 18 kDa (TSPO). TSPO ligands not only promote endogenous neurosteroidogenesis, but also exert a broad spectrum of functions involving modulation of mitochondrial activity and acting as anti-inflammatory and neuroregenerative agents. Besides affective symptoms, in depression cognitive impairment can be frequently observed, which may be ameliorated through targeting of extrasynaptic GABA receptors either via TSPO ligands or exogenously administered 3α-reduced neurosteroids. Interestingly, recent findings indicate an enhanced activation of the complement system, e.g., enhanced expression of C1q, both in depression and dementia. It is of note that benzodiazepines have been shown to reduce long-term potentiation and to cause cognitive decline. Intriguingly, TSPO may be crucial in mediating the effects of benzodiazepines on synaptic pruning. Here, we discuss how benzodiazepines and TSPO may interfere with synaptic pruning. Moreover, we highlight recent developments of TSPO ligands and 3α-reduced neurosteroids as therapeutic agents. Etifoxine is the only clinically available TSPO ligand so far and has been studied in anxiety disorders. Regarding 3α-reduced neurosteroids, brexanolone, an intravenous formulation of allopregnanolone, has been approved for the treatment of postpartum depression and zuranolone, an orally available 3α-reduced neurosteroid, is currently being studied in major depressive disorder and postpartum depression. As such, 3α-reduced neurosteroids and TSPO ligands may constitute promising treatment approaches for affective disorders.
Topics: Humans; Female; Neurosteroids; Anti-Anxiety Agents; Pregnanolone; Ligands; Depression; Depression, Postpartum; Depressive Disorder, Major; Neurotransmitter Agents; Receptors, GABA-A; Benzodiazepines; Carrier Proteins; Neuronal Plasticity; Cognition; gamma-Aminobutyric Acid; Receptors, GABA
PubMed: 36574032
DOI: 10.1007/s00406-022-01532-3 -
Journal of Affective Disorders Apr 2024Major depressive disorder (MDD) and postpartum depression (PPD) are disabling conditions. This integrated analysis of MDD and PPD clinical trials investigated the impact... (Randomized Controlled Trial)
Randomized Controlled Trial
The magnitude and sustainability of treatment benefit of zuranolone on function and well-being as assessed by the SF-36 in adult patients with MDD and PPD: An integrated analysis of 4 randomized clinical trials.
BACKGROUND
Major depressive disorder (MDD) and postpartum depression (PPD) are disabling conditions. This integrated analysis of MDD and PPD clinical trials investigated the impact of zuranolone-a positive allosteric modulator of synaptic and extrasynaptic GABA receptors and neuroactive steroid under investigation for adults with MDD and approved as an oral, once-daily, 14-day treatment course for adults with PPD in the US-on health-related quality of life, including functioning and well-being, as assessed using the 36-item Short Form Health Survey V2 (SF-36).
METHODS
Integrated data from 3 MDD (201B, MOUNTAIN, WATERFALL) and 1 PPD trial (ROBIN) for individual SF-36 domains were compared for zuranolone (30- and 50-mg) vs placebo at Day (D)15 and D42. Comparisons between zuranolone responders (≥50 % reduction from baseline in 17-item Hamilton Depression Rating Scale total score) and nonresponders were assessed.
RESULTS
Overall, 1003 patients were included (zuranolone, n = 504; placebo, n = 499). Significant differences in change from baseline (CFB) to D15 for patients in zuranolone vs placebo groups were observed in 6/8 domains; changes were sustained or improved at D42, with significant CFB differences for all 8 domains. Zuranolone responders had significantly higher CFB scores vs nonresponders for all domains at D15 and D42 (p < 0.001).
LIMITATIONS
Two zuranolone doses were integrated across populations of 2 disease states with potential differences in functioning, comorbidities, and patient demographics. All p-values presented are nominal.
CONCLUSIONS
Integrated data across 4 zuranolone clinical trials showed improvements in functioning and well-being across all SF-36 domains. Benefits persisted after completion of treatment course at D42.
Topics: Adult; Female; Humans; Depressive Disorder, Major; Double-Blind Method; Pregnanolone; Pyrazoles; Quality of Life; Randomized Controlled Trials as Topic; Treatment Outcome
PubMed: 38325605
DOI: 10.1016/j.jad.2024.01.268 -
Journal of Anesthesia Apr 2024Neurosteroids (NS) are a class of steroids that are synthesized within the central nervous system (CNS). Various NS can either enhance or inhibit CNS excitability and... (Review)
Review
Neurosteroids (NS) are a class of steroids that are synthesized within the central nervous system (CNS). Various NS can either enhance or inhibit CNS excitability and they play important biological roles in brain development, brain function and as mediators of mood. One class of NS, 3α-hydroxy-pregnane steroids such as allopregnanolone (AlloP) or pregnanolone (Preg), inhibits neuronal excitability; these endogenous NS and their analogues have been therapeutically applied as anti-depressants, anti-epileptics and general anesthetics. While NS have many favorable properties as anesthetics (e.g. rapid onset, rapid recovery, minimal cardiorespiratory depression, neuroprotection), they are not currently in clinical use, largely due to problems with formulation. Recent advances in understanding NS mechanisms of action and improved formulations have rekindled interest in development of NS as sedatives and anesthetics. In this review, the synthesis of NS, and their mechanism of action will be reviewed with specific emphasis on their binding sites and actions on γ-aminobutyric acid type A (GABA) receptors. The potential advantages of NS analogues as sedative and anesthetic agents will be discussed.
Topics: Anesthetics, General; Neurosteroids; Anesthetics; Pregnanolone; gamma-Aminobutyric Acid; Receptors, GABA-A
PubMed: 38252143
DOI: 10.1007/s00540-023-03291-4 -
Cell Jun 2024Recent studies suggest that human-associated bacteria interact with host-produced steroids, but the mechanisms and physiological impact of such interactions remain...
Recent studies suggest that human-associated bacteria interact with host-produced steroids, but the mechanisms and physiological impact of such interactions remain unclear. Here, we show that the human gut bacteria Gordonibacter pamelaeae and Eggerthella lenta convert abundant biliary corticoids into progestins through 21-dehydroxylation, thereby transforming a class of immuno- and metabo-regulatory steroids into a class of sex hormones and neurosteroids. Using comparative genomics, homologous expression, and heterologous expression, we identify a bacterial gene cluster that performs 21-dehydroxylation. We also uncover an unexpected role for hydrogen gas production by gut commensals in promoting 21-dehydroxylation, suggesting that hydrogen modulates secondary metabolism in the gut. Levels of certain bacterial progestins, including allopregnanolone, better known as brexanolone, an FDA-approved drug for postpartum depression, are substantially increased in feces from pregnant humans. Thus, bacterial conversion of corticoids into progestins may affect host physiology, particularly in the context of pregnancy and women's health.
Topics: Humans; Progestins; Hydrogen; Gastrointestinal Microbiome; Female; Glucocorticoids; Pregnancy; Animals; Multigene Family; Feces; Pregnanolone; Mice
PubMed: 38795705
DOI: 10.1016/j.cell.2024.05.005 -
The Journal of Pharmacology and... Jan 2024This article describes recent advances in the use of neurosteroids as novel anticonvulsants for refractory status epilepticus (RSE) and as medical countermeasures (MCs)... (Review)
Review
Neurosteroids as Novel Anticonvulsants for Refractory Status Epilepticus and Medical Countermeasures for Nerve Agents: A 15-Year Journey to Bring Ganaxolone from Bench to Clinic.
This article describes recent advances in the use of neurosteroids as novel anticonvulsants for refractory status epilepticus (RSE) and as medical countermeasures (MCs) for organophosphates and chemical nerve agents (OPNAs). We highlight a comprehensive 15-year journey to bring the synthetic neurosteroid ganaxolone (GX) from bench to clinic. RSE, including when caused by nerve agents, is associated with devastating morbidity and permanent long-term neurologic dysfunction. Although recent approval of benzodiazepines such as intranasal midazolam and intranasal midazolam offers improved control of acute seizures, novel anticonvulsants are needed to suppress RSE and improve neurologic function outcomes. Currently, few anticonvulsant MCs exist for victims of OPNA exposure and RSE. Standard-of-care MCs for postexposure treatment include benzodiazepines, which do not effectively prevent or mitigate seizures resulting from nerve agent intoxication, leaving an urgent unmet medical need for new anticonvulsants for RSE. Recently, we pioneered neurosteroids as next-generation anticonvulsants that are superior to benzodiazepines for treatment of OPNA intoxication and RSE. Because GX and related neurosteroids that activate extrasynaptic GABA-A receptors rapidly control seizures and offer robust neuroprotection by reducing neuronal damage and neuroinflammation, they effectively improve neurologic outcomes after acute OPNA exposure and RSE. GX has been selected for advanced, Biomedical Advanced Research and Development Authority-supported phase 3 trials of RSE and nerve agent seizures. In addition, in mechanistic studies of neurosteroids at extrasynaptic receptors, we identified novel synthetic analogs with features that are superior to GX for current medical needs. Development of new MCs for RSE is complex, tedious, and uncertain due to scientific and regulatory challenges. Thus, further research will be critical to fill key gaps in evaluating RSE and anticonvulsants in vulnerable (pediatric and geriatric) populations and military persons. SIGNIFICANCE STATEMENT: Following organophosphate and nerve agent intoxication, refractory status epilepticus (RSE) occurs despite benzodiazepine treatment. RSE occurs in 40% of status epilepticus patients, with a 35% mortality rate and significant neurological morbidity in survivors. To treat RSE, neurosteroids are better anticonvulsants than benzodiazepines. Our pioneering use of neurosteroids for RSE and nerve agents led us to develop ganaxolone as a novel anticonvulsant and neuroprotectant with significantly improved neurological outcomes. This article describes the bench-to-bedside journey of bringing neurosteroid therapy to patients, with ganaxolone leading the way.
Topics: Humans; Child; Aged; Anticonvulsants; Nerve Agents; Neurosteroids; Midazolam; Medical Countermeasures; Status Epilepticus; Seizures; Benzodiazepines; Organophosphates; Pregnanolone
PubMed: 37977814
DOI: 10.1124/jpet.123.001816 -
Frontiers in Endocrinology 2023Previous studies demonstrated the inhibitory effect of allopregnanolone (3α,5α-THP) on the activation of inflammatory toll-like receptor 4 (TLR4) signals in RAW264.7...
BACKGROUND
Previous studies demonstrated the inhibitory effect of allopregnanolone (3α,5α-THP) on the activation of inflammatory toll-like receptor 4 (TLR4) signals in RAW264.7 macrophages and the brains of selectively bred alcohol-preferring (P) rats. In the current study, we investigated the impact of 3α,5α-THP on the levels of IL-10 and activation of the TRIF-dependent endosomal TLR4 pathway.
METHODS
The amygdala and nucleus accumbens (NAc) of P rats, which exhibit innately activated TLR4 pathways as well as RAW264.7 cells, were used. Enzyme-linked immunosorbent assays (ELISA) and immunoblotting assays were used to ascertain the effects of 3α,5α-THP on the TRIF-dependent endosomal TLR4 pathway and endosomes were isolated to examine translocation of TLR4 and TRIF. Additionally, we investigated the effects of 3α,5α-THP and 3α,5α-THDOC (0.1, 0.3, and 1.0 µM) on the levels of IL-10 in RAW264.7 macrophages. Finally, we examined whether inhibiting TRIF (using TRIF siRNA) in RAW264.7 cells altered the levels of IL-10.
RESULTS
3α,5α-THP administration facilitated activation of the endosomal TRIF-dependent TLR4 pathway in males, but not female P rats. 3α,5α-THP increased IL-10 levels (+13.2 ± 6.5%) and BDNF levels (+21.1 ± 11.5%) in the male amygdala. These effects were associated with increases in pTRAM (+86.4 ± 28.4%), SP1 (+122.2 ± 74.9%), and PI(3)K-p110δ (+61.6 ± 21.6%), and a reduction of TIRAP (-13.7 ± 6.0%), indicating the activation of the endosomal TRIF-dependent TLR4 signaling pathway. Comparable effects were observed in NAc of these animals. Furthermore, 3α,5α-THP enhanced the accumulation of TLR4 (+43.9 ± 11.3%) and TRIF (+64.8 ± 32.8%) in endosomes, with no significant effect on TLR3 accumulation. Additionally, 3α,5α-THP facilitated the transition from early endosomes to late endosomes (increasing Rab7 levels: +35.8 ± 18.4%). In RAW264.7 cells, imiquimod (30 µg/mL) reduced IL-10 while 3α,5α-THP and 3α,5α-THDOC (0.1, 0.3, and 1.0 µM) restored IL-10 levels. To determine the role of the TRIF-dependent TLR4 signaling pathway in IL-10 production, the downregulation of TRIF (-62.9 ± 28.2%) in RAW264.7 cells led to a reduction in IL-10 levels (-42.3 ± 8.4%). TRIF (-62.9 ± 28.2%) in RAW264.7 cells led to a reduction in IL-10 levels (-42.3 ± 8.4%) and 3α,5α-THP (1.0 µM) no longer restored the reduced IL-10 levels.
CONCLUSION
The results demonstrate 3α,5α-THP enhancement of the endosomal TLR4-TRIF anti-inflammatory signals and elevations of IL-10 in male P rat brain that were not detected in female P rat brain. These effects hold significant implications for controlling inflammatory responses in both the brain and peripheral immune cells.
Topics: Animals; Female; Male; Rats; Adaptor Proteins, Vesicular Transport; Endosomes; Interleukin-10; Neurosteroids; Pregnanolone; Signal Transduction; Toll-Like Receptor 4; RAW 264.7 Cells; Mice
PubMed: 38179300
DOI: 10.3389/fendo.2023.1299420 -
Neuropsychopharmacology : Official... Aug 2023Ample evidence suggests that acute stress can worsen symptom severity in Tourette syndrome (TS); however, the neurobiological underpinnings of this phenomenon remain...
Ample evidence suggests that acute stress can worsen symptom severity in Tourette syndrome (TS); however, the neurobiological underpinnings of this phenomenon remain poorly understood. We previously showed that acute stress exacerbates tic-like and other TS-associated responses via the neurosteroid allopregnanolone (AP) in an animal model of repetitive behavioral pathology. To verify the relevance of this mechanism to tic pathophysiology, here we tested the effects of AP in a mouse model recapitulating the partial depletion of dorsolateral cholinergic interneurons (CINs) seen in post-mortem studies of TS. Mice underwent targeted depletion of striatal CINs during adolescence and were tested in young adulthood. Compared with controls, partially CIN-depleted male mice exhibited several TS-relevant abnormalities, including deficient prepulse inhibition (PPI) and increased grooming stereotypies after a 30-min session of spatial confinement - a mild acute stressor that increases AP levels in the prefrontal cortex (PFC). These effects were not seen in females. Systemic and intra-PFC AP administration dose-dependently worsened grooming stereotypies and PPI deficits in partially CIN-depleted males. Conversely, both AP synthesis inhibition and pharmacological antagonism reduced the effects of stress. These results further suggest that AP in the PFC mediates the adverse effects of stress on the severity of tics and other TS-related manifestations. Future studies will be necessary to confirm these mechanisms in patients and define the circuitry responsible for the effects of AP on tics.
Topics: Female; Male; Mice; Animals; Tics; Pregnanolone; Tourette Syndrome; Disease Models, Animal; Stereotyped Behavior
PubMed: 37198434
DOI: 10.1038/s41386-023-01603-6 -
Expert Opinion on Pharmacotherapy 2024Major depressive disorder (MDD) is a common and debilitating mental illness. Postpartum depression (PPD) impacts women globally and is one of the most common... (Review)
Review
INTRODUCTION
Major depressive disorder (MDD) is a common and debilitating mental illness. Postpartum depression (PPD) impacts women globally and is one of the most common complications of childbirth that is underdiagnosed and undertreated, adversely impacting the mental health of women, children, and partners.Available antidepressant medications require weeks to months before showing effect. In this setting, zuranolone, an oral neuroactive steroid and a positive allosteric modulator of GABA receptors, is an attractive alternative as a rapid-acting antidepressant treatment.
AREAS COVERED
This article reviews zuranolone (SAGE217), focusing on available clinical studies in individuals with PPD and MDD. This paper adds to the extant literature by presenting the efficacy data as Number Needed to Treat (NNT) to facilitate indirect comparisons with other antidepressants.
EXPERT OPINION
Zuranolone is a novel rapid-acting (i.e. two week course) oral antidepressant for the treatment of adults with PPD with ongoing clinical trials evaluating its efficacy in adults with MDD. Zuranolone is well tolerated with no significant safety concerns in any clinical trials completed to date. Zuranolone will be scheduled by the Drug Enforcement Agency (DEA).
Topics: Adult; Child; Female; Humans; Depressive Disorder, Major; Depression, Postpartum; Antidepressive Agents; Pregnanolone; Pyrazoles
PubMed: 38164653
DOI: 10.1080/14656566.2023.2298340 -
Progress in Neuro-psychopharmacology &... Jun 2024Postpartum depression (PPD) poses a major threat to maternal mental health and wellbeing while also adversely affecting the mother's relationship with her baby, leading... (Review)
Review
Postpartum depression (PPD) poses a major threat to maternal mental health and wellbeing while also adversely affecting the mother's relationship with her baby, leading to significant repercussions that may hinder the growth and cognitive development of the child. For decades, antidepressants have been the mainstay of treating PPD; however, recent evidence suggests that antidepressants are not as effective as they are believed to be and there is a dire need to explore new treatment options. In 2023, a breakthrough in treating PPD emerged with the recent FDA approval of zuranolone, a gamma-aminobutyric acid (GABA) receptor selective positive allosteric modulator. The implementation of zuranolone in treating PPD can prove to be revolutionary, considering it is the first oral medication available for PPD. Our review aims to discuss the various clinical trials that have been conducted to validate the efficacy of zuranolone in mitigating the symptoms of PPD, hence, leading to better outcomes for mothers.
Topics: Humans; Female; Child; Depression, Postpartum; Pregnanolone; Pyrazoles; Antidepressive Agents
PubMed: 38412941
DOI: 10.1016/j.pnpbp.2024.110983 -
Biological Psychiatry Aug 2023Chronic stress is a major risk factor for psychiatric illnesses, including depression. However, the pathophysiological mechanisms whereby stress leads to mood disorders...
BACKGROUND
Chronic stress is a major risk factor for psychiatric illnesses, including depression. However, the pathophysiological mechanisms whereby stress leads to mood disorders remain unclear. Allopregnanolone acts as a positive allosteric modulator preferentially on δ subunit-containing GABA (gamma-aminobutyric acid A) receptors. Accumulating clinical and preclinical evidence supports the antidepressant effects of exogenous administration of allopregnanolone analogs; yet, the role of endogenous allopregnanolone in the pathophysiology of depression remains unknown.
METHODS
We utilized a chronic unpredictable stress (CUS) mouse model, followed by behavioral and biochemical assays, to examine whether altered neurosteroid signaling contributes to behavioral outcomes following CUS. We subsequently performed in vivo CRISPR (clustered regularly interspaced short palindromic repeats) knockdown of rate-limiting enzymes involved in allopregnanolone synthesis, 5α-reductase type 1 and 2 (5α1/2), in addition to lentiviral overexpression of 5α1/2 in the basolateral amygdala (BLA) of mice that underwent CUS to assess the impact of 5α1/2 on behavioral outcomes.
RESULTS
The expression of δ subunit-containing GABA receptors and endogenous levels of allopregnanolone were reduced in the BLA following CUS. Treatment with an exogenous allopregnanolone analog, SGE-516, was sufficient to increase allopregnanolone levels in the BLA following CUS. Knockdown of 5α1/2 in the BLA mimicked the behavioral outcomes associated with CUS. Conversely, overexpression of 5α1/2 in the BLA improved behavioral outcomes following CUS.
CONCLUSIONS
Our findings demonstrate that chronic stress impairs endogenous neurosteroid signaling in the BLA, which is sufficient to induce behavioral deficits. Further, these studies suggest that allopregnanolone-based treatments may directly target the underlying pathophysiology of mood disorders suggesting that targeting endogenous neurosteroidogenesis may offer a novel therapeutic strategy.
Topics: Mice; Animals; Pregnanolone; Receptors, GABA-A; Neurosteroids; Signal Transduction; gamma-Aminobutyric Acid
PubMed: 36736870
DOI: 10.1016/j.biopsych.2023.01.022