Allopregnanolone: From molecular pathophysiology to therapeutics. A historical perspective

Conversion of 5α-Androstane-3α,17β-diol to bis[(4-dimethylamino)phenyl carbamate] derivative for sensitive determination of its rat brain level by LC/ESI-MS/MS

RATIONALE

5α-Androstane-3α,17β-diol (3α,5α-Adiol) is a testosterone-derived neurosteroid and has anxiolytic and analgesic effects via γ-aminobutyric acid type A receptors as with the progesterone-derived neurosteroid, allopregnanolone (AP). Although the psychotropic drug-evoked changes in the brain AP concentration have been intensively studied, those in the brain 3α,5α-Adiol concentration remain poorly understood. One of the causes for this is the limited availability of a validated method for quantifying the brain 3α,5α-Adiol with a sufficient sensitivity and specificity, which is described in this study.

METHODS

To enhance the detectability of 3α,5α-Adiol by electrospray ionization-tandem mass spectrometry (ESI-MS/MS), derivatization with 4-dimethylaminobenzoyl azide was employed. The brain sample was purified by solid-phase extraction and the recovered 3α,5α-Adiol and the deuterated internal standard were derivatized, then measured by liquid chromatography (LC)/ESI-MS/MS with selected reaction monitoring.

RESULTS

The derivatized 3α,5α-Adiol, i.e., the bis[(4-dimethylamino)phenyl carbamate] derivative, provided the intense doubly-protonated molecule as the precursor ion, then the specific product ion containing the 3α,5α-Adiol-skeleton by collision-induced dissociation. The detectability of 3α,5α-Adiol was eventually increased 1000-fold by derivatization. Separation of the derivatized 3α,5α-Adiol from its stereoisomers and interfering brain components was achieved using a SunShell Biphenyl column with an isopropyl alcohol-containing mobile phase. A good linearity in the sufficient concentration range, acceptable precision and accuracy, and negligible matrix effect were demonstrated by the validation tests. The animal (rat) study using this method revealed that the brain 3α,5α-Adiol levels were unaffected by the administration of fluoxetine (FLX) and clozapine (CLZ), in contrast to the significant increase of the AP levels.

CONCLUSION

An LC/ESI-MS/MS method capable of quantifying 3α,5α-Adiol in the rat brain using a 20-mg tissue was developed and validated. The brain levels of 3α,5α-Adiol had an entirely different behavior from those of AP due to FLX and CLZ administration.

New treatments: Opportunities and challenges

Across the spectrum of perinatal mental illness, there exist a variety of effective treatments. However, the available treatments are not always matched to the presentation, resources, constraints, or values of each patient. Furthermore, provider, local, and systemic factors complicate access to current treatment options. New and emerging approaches offer the potential of more effective treatment for specific perinatal psychiatric disorders. From neuroactive steroid medications to accelerated psychotherapy interventions, recent innovations have demonstrated enhanced efficacy on a faster timeline. Optimally, these developments will also lower barriers to care but this is not necessarily true. We review novel and upcoming interventions across perinatal mental illness and place them in the context of existing treatments and common challenges.

Dimensional Affective Sensitivity to Hormones across the Menstrual Cycle (DASH-MC): A transdiagnostic framework for ovarian steroid influences on psychopathology

Fluctuations in progesterone (P4) and estradiol (E2) across the menstrual cycle can exert direct effects on biological systems implicated in neuropsychiatric disorders and represent a key biological source of variability in affective, cognitive, and behavioral disorders. Although these cyclical symptoms may be most readily identified when they occur exclusively in relation to the menstrual cycle, as in DSM-5 premenstrual dysphoric disorder, symptom changes of similar magnitude occur in a larger proportion of people with ongoing psychiatric disorders. Studies investigating cyclical regulation of brain and behavior often produce inconsistent results, which may be attributed to a lack of focus on specific hormonal events and individual differences in related sensitivities. We propose a transdiagnostic Dimensional Affective Sensitivity to Hormones across the Menstrual Cycle (DASH-MC) framework, postulating that atypical neural responses to several key hormonal events provoke specific temporal patterns of affective and behavioral change across the menstrual cycle. We review prospective and experimental evidence providing initial support for these dimensions, which include (1) luteal-onset negative affect caused by a sensitivity to E2 or P4 surges (mediated by neuroactive metabolites such as allopregnanolone), typified by irritability and hyperarousal; (2) perimenstrual-onset negative affect caused by a sensitivity to low or falling E2, typified by low mood and cognitive dysfunction; and (3) preovulatory-onset positive affect dysregulation caused by a sensitivity to E2 surges, typified by harmful substance use and other risky reward-seeking. This multidimensional, transdiagnostic framework for hormone sensitivity can inform more precise research on ovarian steroid regulation of psychopathology, including further mechanistic research, diagnostic refinement, and precision psychiatry treatment development. Additionally, given the high rates of hormone sensitivity across affective disorders, the DASH-MC may guide broader insights into the complex neurobiological vulnerabilities driving female-biased affective risk, as well as potential triggers and mechanisms of affective state change in psychiatric disorders.

Allopregnanolone in the peripartum: Correlates, concentrations, and challenges - A systematic review

BACKGROUND

Allopregnanolone (ALLO) is a metabolite of progesterone and a neuroactive steroid hormone. As a positive allosteric modulator of gamma-aminobutyric acid (GABA) receptors, ALLO seems to have antidepressant and anxiolytic effects, and was therefore approved as a specific medication for the treatment of postpartum depression in 2019. Despite the growing number of publications investigating ALLO levels, results on the biological and psychological correlates in the peripartum period remain inconsistent, possibly due to methodological challenges regarding measurement. To date, however, there is no systematic review examining the correlates, concentrations, and challenges in measuring ALLO in peripartum women.

METHOD

A systematic literature search of PubMed and PsycINFO was conducted in August 2023. Original research articles that measured ALLO concentrations in peripartum women were included. Reports were excluded if they were not original research, included non-human subjects, did not include peripartum women, did not include ALLO measurement as an outcome, included (pharmacological) interventions, constituted method validations, or used the same cohort as another study.

RESULTS

The literature search yielded 234 articles, and two articles were identified from other sources. After full-text screening, 19 articles (N = 1401) met the inclusion criteria, of which seven focused on biological correlates of ALLO and 12 on mood correlates. Of the latter, six found no association between ALLO and mood, four found a negative association, and two found a positive association. Overall, the results show an increase in ALLO levels during pregnancy and a decrease after birth, with levels then remaining low until six months postpartum. ALLO was most commonly measured in blood plasma and by gas chromatography-mass spectrometry (GC-MS). A significant matrix effect was found for blood serum and a significant method effect for radioimmunoassays (RIAs). A significant effect of time of measurement was found.

CONCLUSION

ALLO measurement shows method and matrix effects. ALLO levels are higher when measured in serum compared to in plasma, and when measured using RIA compared to other methods. Time of measurement, study design, and standardization of measurement also influence the reliability of measurement and the interpretation of results.

Neurosteroids and translocator protein 18 kDa (TSPO) ligands as novel treatment options in depression

Recently, the gamma-aminobutyric acid (GABA) system has come into focus for the treatment of anxiety, postpartum depression, and major depressive disorder. Endogenous 3α-reduced steroids such as allopregnanolone are potent positive allosteric modulators of GABAA receptors and have been known for decades. Current industry developments and first approvals by the U.S. food and drug administration (FDA) for the treatment of postpartum depression with exogenous analogues of these steroids represent a major step forward in the field. 3α-reduced steroids target both synaptic and extrasynaptic GABAA receptors, unlike benzodiazepines, which bind to synaptic receptors. The first FDA-approved 3α-reduced steroid for postpartum depression is brexanolone, an intravenous formulation of allopregnanolone. It has been shown to provide rapid relief of depressive symptoms. An orally available 3α-reduced steroid is zuranolone, which also received FDA approval in 2023 for the treatment of postpartum depression. Although a number of studies have been conducted, the efficacy data were not sufficient to achieve approval of zuranolone in major depressive disorder by the FDA in 2023. The most prominent side effects of these 3α-reduced steroids are somnolence, dizziness and headache. In addition to the issue of efficacy, it should be noted that current data limit the use of these compounds to two weeks. An alternative to exogenous 3α-reduced steroids may be the use of substances that induce endogenous neurosteroidogenesis, such as the translocator protein 18 kDa (TSPO) ligand etifoxine. TSPO has been extensively studied for its role in steroidogenesis, in addition to other functions such as anti-inflammatory and neuroregenerative properties. Currently, etifoxine is the only clinically available TSPO ligand in France for the treatment of anxiety disorders. Studies are underway to evaluate its antidepressant potential. Hopefully, neurosteroid research will lead to the development of fast-acting antidepressants.

Factors promoting the release of picrotoxin from the trap in the GABA(A) receptor pore

Picrotoxin (PTX), a convulsant of plant origin, has been used in many studies as research tool. PTX is the open channel blocker of the GABAA receptor (GABAAR). Being in the pore, PTX initiates transfer of the channel to the closed state and thus it falls into the "trap". The consequence of this PTX trapping is so-called aftereffect, i.e. continuation of the blockade of the GABA-induced chloride current (IGABA) after removal of PTX from the external solution. The present work shows that the positive allosteric modulators (PAMs) of the GABAA receptor, allopregnanolone (Allo) and zolpidem (Zolp) as well as a high concentration of GABA shortened the PTX aftereffect. Experiments were carried out on isolated Purkinje neurons of the rat cerebellum using the whole-cell patch-clamp method. IGABA was induced by applications of 5 μM GABA (EC30) for 1 s with 30 s intervals. 50 μM PTX completely blocked IGABA, and recovery upon PTX washout occurred with a time constant (τrec) of 20.2 min. 1 μM Allo reduced the blocking effect of PTX by 30% and accelerated the recovery of IGABA by almost 10 times (τrec = 2.4 min). 0.5 μM Zolp did not change the IGABA block in the presence of PTX but accelerated the recovery of IGABA by more than 3 times (τrec = 5.6 min). Increasing the GABA concentration to 20 μM did not change the blocking effect of PTX, but accelerated recovery by 6 times (τrec = 3.3 min). The mechanism of the shortening of the PTX aftereffect is presumably the expansion of the GABAAR pore in the presence of PAMs and a high concentration of the agonist and, as a consequence, the escape of PTX from the "trap". The work describes new pharmacological properties of Allo and Zolp.

Neuroactive Steroids, Toll-like Receptors, and Neuroimmune Regulation: Insights into Their Impact on Neuropsychiatric Disorders

Pregnane neuroactive steroids, notably allopregnanolone and pregnenolone, exhibit efficacy in mitigating inflammatory signals triggered by toll-like receptor (TLR) activation, thus attenuating the production of inflammatory factors. Clinical studies highlight their therapeutic potential, particularly in conditions like postpartum depression (PPD), where the FDA-approved compound brexanolone, an intravenous formulation of allopregnanolone, effectively suppresses TLR-mediated inflammatory pathways, predicting symptom improvement. Additionally, pregnane neurosteroids exhibit trophic and anti-inflammatory properties, stimulating the production of vital trophic proteins and anti-inflammatory factors. Androstane neuroactive steroids, including estrogens and androgens, along with dehydroepiandrosterone (DHEA), display diverse effects on TLR expression and activation. Notably, androstenediol (ADIOL), an androstane neurosteroid, emerges as a potent anti-inflammatory agent, promising for therapeutic interventions. The dysregulation of immune responses via TLR signaling alongside reduced levels of endogenous neurosteroids significantly contributes to symptom severity across various neuropsychiatric disorders. Neuroactive steroids, such as allopregnanolone, demonstrate efficacy in alleviating symptoms of various neuropsychiatric disorders and modulating neuroimmune responses, offering potential intervention avenues. This review emphasizes the significant therapeutic potential of neuroactive steroids in modulating TLR signaling pathways, particularly in addressing inflammatory processes associated with neuropsychiatric disorders. It advances our understanding of the complex interplay between neuroactive steroids and immune responses, paving the way for personalized treatment strategies tailored to individual needs and providing insights for future research aimed at unraveling the intricacies of neuropsychiatric disorders.

Potential therapeutic effects of Chinese herbal medicine in postpartum depression: Mechanisms and future directions

ETHNOPHARMACOLOGICAL RELEVANCE

Postpartum depression (PPD) is a common psychiatric disorder in women after childbirth. Per data from epidemiologic studies, PPD affects about 5%-26.32% of postpartum mothers worldwide. Biological factors underlying this condition are multiple and complex and have received extensive inquiries for the roles they play in PPD. Chinese herbal medicine (CHM), which is widely used as a complementary and alternative therapy for neurological disorders, possesses multi-component, multi-target, multi-access, and low side effect therapeutic characteristics. CHM has already shown efficacy in the treatment of PPD, and a lot more research exploring the mechanisms of its potential therapeutic effects is being conducted.

AIM OF THE REVIEW

This review provides an in-depth and comprehensive overview of the underlying mechanisms of PPD, as well as samples the progress made in researching the potential role of CHM in treating the disorder.

MATERIALS AND METHODS

Literature was searched comprehensively in scholarly electronic databases, including PubMed, Web of Science, Scopus, CNKI and WanFang DATA, using the search terms "postpartum depression", "genetic", "hormone", "immune", "neuroinflammation", "inflammation", "neurotransmitter", "neurogenesis", "brain-gut axis", "traditional Chinese medicine", "Chinese herbal medicine", "herb", and an assorted combination of these terms.

RESULTS

PPD is closely associated with genetics, as well as with the hormones, immune inflammatory, and neurotransmitter systems, neurogenesis, and gut microbes, and these biological factors often interact and work together to cause PPD. For example, inflammatory factors could suppress the production of the neurotransmitter serotonin by inducing the regulation of tryptophan-kynurenine in the direction of neurotoxicity. Many CHM constituents improve anxiety- and depression-like behaviors by interfering with the above-mentioned mechanisms and have shown decent efficacy clinically against PPD. For example, Shen-Qi-Jie-Yu-Fang invigorates the neuroendocrine system by boosting the hormone levels of hypothalamic pituitary adrenal (HPA) and hypothalamic pituitary gonadal (HPG) axes, regulating the imbalance of Treg/T-helper cells (Th) 17 and Th1/Th2, and modulating neurotransmitter system to play antidepressant roles. The Shenguiren Mixture interferes with the extracellular signal-regulated kinase (ERK) pathway to enhance the number, morphology and apoptosis of neurons in the hippocampus of PPD rats. Other herbal extracts and active ingredients of CHM, such as Paeoniflorin, hypericin, timosaponin B-III and more, also manage depression by remedying the neuroendocrine system and reducing neuroinflammation.

CONCLUSIONS

The pathogenesis of PPD is complex and diverse, with the main pathogenesis not clear. Still, CHM constituents, like Shen-Qi-Jie-Yu-Fang, the Shenguiren Mixture, Paeoniflorin, hypericin and other Chinese Medicinal Formulae, active monomers and Crude extracts, treats PPD through multifaceted interventions. Therefore, developing more CHM components for the treatment of PPD is an essential step forward.

Neurosteroid Modulation of Synaptic and Extrasynaptic GABAA Receptors of the Mouse Nucleus Accumbens

The recent approval of formulations of the endogenous neurosteroid allopregnanolone (brexanolone) and the synthetic neuroactive steroid SAGE-217 (zuranolone) to treat postpartum depression (PPD) has encouraged further research to elucidate why these potent enhancers of GABAAR function are clinically effective in this condition. Dopaminergic projections from the ventral tegmental area (VTA) to the nucleus accumbens are associated with reward/motivation and brain imaging studies report that individuals with PPD show reduced activity of this pathway in response to reward and infant engagement. However, the influence of neurosteroids on GABA-ergic transmission in the nucleus accumbens has received limited attention. Here, we investigate, in the medium spiny neurons (MSNs) of the mouse nucleus accumbens core, the effect of allopregnanolone, SAGE-217 and other endogenous and synthetic steroids of interest on fast phasic and tonic inhibition mediated by synaptic (α1/2βγ2) and extrasynaptic (α4βδ) GABAARs, respectively. We present evidence suggesting the resident tonic current results from the spontaneous opening of δ-GABAARs, where the steroid-enhanced tonic current is GABA-dependent. Furthermore, we demonstrate local neurosteroid synthesis in the accumbal slice preparation and reveal that GABA-ergic neurotransmission of MSNs is influenced by an endogenous neurosteroid tone. Given the dramatic fluctuations in allopregnanolone levels during pregnancy and postpartum, this neurosteroid-mediated local fine-tuning of GABAergic transmission in the MSNs will probably be perturbed.

Witnessed trauma exposure induces fear in mice through a reduction in endogenous neurosteroid synthesis

Neurosteroids have been implicated in the pathophysiology of post-traumatic stress disorder (PTSD). Allopregnanolone is reduced in subsets of individuals with PTSD and has been explored as a novel treatment strategy. Both direct trauma exposure and witnessed trauma are risk factors for PTSD; however, the role of neurosteroids in the behavioral outcomes of these unique experiences has not been explored. Here, we investigate whether observational fear is associated with a reduced capacity for endogenous neurosteroidogenesis and the relationship with behavioral outcomes. We demonstrated that mice directly subjected to a threat (foot shocks) and those witnessing the threat have decreased plasma levels of allopregnanolone. The expression of a key enzyme involved in endogenous neurosteroid synthesis, 5α-reductase type 2, is decreased in the basolateral amygdala, which is a major emotional processing hub implicated in PTSD. We demonstrated that genetic knockdown or pharmacological inhibition of 5α-reductase type 2 exaggerates the behavioral expression of fear in response to witnessed trauma, whereas oral treatment with an exogenous, synthetic neuroactive steroid gamma-aminobutyric acid-A receptor positive allosteric modulator with molecular pharmacology similar to allopregnanolone (SGE-516 [tool compound]) decreased the behavioral response to observational fear. These data implicate impaired endogenous neurosteroidogenesis in the pathophysiology of threat exposure, both direct and witnessed. Further, these data suggest that treatment with exogenous 5α-reduced neurosteroids or targeting endogenous neurosteroidogenesis may be beneficial for the treatment of individuals with PTSD, whether resulting from direct or witnessed trauma.

The role of neurosteroids in posttraumatic stress disorder and alcohol use disorder: A review of 10 years of clinical literature and treatment implications

Rates of alcohol use disorder (AUD) are increasing in men and women and there are high rates of concurrent posttraumatic stress disorder (PTSD) and AUD. AUD and PTSD synergistically increase symptomatology and negatively affect treatment outcomes; however, there are very limited pharmacological treatments for PTSD/AUD. Neurosteroids have been implicated in the underlying neurobiological mechanisms of both PTSD and AUD and may be a target for treatment development. This review details the past ten years of research on pregnenolone, progesterone, allopregnanolone, pregnanolone, estradiol, testosterone and dehydroepiandrosterone/dehydroepiandrosterone-sulfate (DHEA/DHEA-S) in the context of PTSD and AUD, including examination of trauma/alcohol-related variables, such as stress-reactivity. Emerging evidence that exogenous pregnenolone, progesterone, and allopregnanolone may be promising, novel interventions is also discussed. Specific emphasis is placed on examining the application of sex as a biological variable in this body of literature, given that women are more susceptible to both PTSD diagnoses and stress-related alcohol consumption.

Local effect of allopregnanolone in rat ovarian steroidogenesis, follicular and corpora lutea development

Allopregnanolone (ALLO) is a known neurosteroid and a progesterone metabolite synthesized in the ovary, CNS, PNS, adrenals and placenta. Its role in the neuroendocrine control of ovarian physiology has been studied, but its in situ ovarian effects are still largely unknown. The aims of this work were to characterize the effects of intrabursal ALLO administration on different ovarian parameters, and the probable mechanism of action. ALLO administration increased serum progesterone concentration and ovarian 3β-HSD2 while decreasing 20α-HSD mRNA expression. ALLO increased the number of atretic follicles and the number of positive TUNEL granulosa and theca cells, while decreasing positive PCNA immunostaining. On the other hand, there was an increase in corpora lutea diameter and PCNA immunostaining, whereas the count of TUNEL-positive luteal cells decreased. Ovarian angiogenesis and the immunohistochemical expression of GABAA receptor increased after ALLO treatment. To evaluate if the ovarian GABAA receptor was involved in these effects, we conducted a functional experiment with a specific antagonist, bicuculline. The administration of bicuculline restored the number of atretic follicles and the diameter of corpora lutea to normal values. These results show the actions of ALLO on the ovarian physiology of the female rat during the follicular phase, some of them through the GABAA receptor. Intrabursal ALLO administration alters several processes of the ovarian morpho-physiology of the female rat, related to fertility and oocyte quality.

Behavioral characterization of co-exposure to cannabinoids and hormonal contraceptives in female rats

Hormonal contraceptives are among the most widely used drugs by young healthy women to block ovulation and avoid pregnancy. They reduce the ovarian secretion of estradiol and progesterone, hormones that also modulate neuronal plasticity, cognitive functions, emotions and mood. Cannabis is the most commonly used illicit drug worldwide and its use is increasing among young women, many of which regularly take the "pill". Despite evidence of a bidirectional interaction between the endocannabinoid system and gonadal hormones, only very few studies have examined the consequences of cannabis consumption in young females under hormonal contraceptives treatment. To fill this gap, this study evaluated the behavioral effects of co-exposure to chronic 1) hormonal contraceptives, i.e., ethinyl estradiol (EE) plus levonorgestrel (LNG), one of the synthetic estrogen-progestin combinations of hormonal contraceptives, and 2) cannabinoid receptor agonist, i.e., WIN 55,212-2 (WIN), on motor activity, emotional state and cognitive functions in young adult female rats (8-11/experimental group). Hormonal and cannabinoid treatment started at post-natal day (PND) 52 and 56, respectively, while behavioral testing occurred between PND 84-95. The results show that chronic EE-LNG treatment, at doses (0.020 and 0.060 mg/rat, respectively) known to drastically reduce plasma progesterone levels, and the contextual exposure to WIN, at a dose (12.5 μg/kg/infusion) known to be rewarding in the rat, alters the hormonal milieu but does not cause further changes in locomotor activity compared to EE-LNG or WIN alone, and does not modify anxiety-like state (as measured by the elevated plus maze and the marble burying tests) and cognitive abilities (as measured by the novel object recognition and the prepulse inhibition tests) in young adult female rats. Although exposure to EE-LNG and WIN tends to increase the duration of immobility and to reduce the time spent swimming in the forced swimming test, there was not a significant additive effect suggestive of a depressive-like state. These findings allow deepening the current knowledge on the interaction between cannabinoid agonists and hormonal contraceptives and suggest that low, rewarding doses of cannabinoids do not significantly alter the motor and cognitive skills and do not induce anxiety or depressive-like states in females that use hormonal contraceptives.

Efficacy and safety of zuranolone co-initiated with an antidepressant in adults with major depressive disorder: results from the phase 3 CORAL study

Major depressive disorder (MDD) is a mental health disorder that can cause disability and functional impairment that standard-of-care (SOC) antidepressant therapies (ADTs) can take weeks to treat. Zuranolone is a neuroactive steroid and positive allosteric modulator of synaptic and extrasynaptic γ-aminobutyric acid (GABA) type A receptors approved as an oral, once-daily, 14-day treatment course in adults with postpartum depression and under investigation in adults with MDD. The phase 3 CORAL Study (NCT04476030) evaluated the efficacy and safety of zuranolone 50 mg co-initiated with SOC ADT (zuranolone+ADT) vs placebo co-initiated with SOC ADT (placebo+ADT) in adults with MDD. Patients were randomized 1:1 to once-daily, blinded zuranolone+ADT or placebo+ADT for 14 days, then continued open-label SOC ADT for 28 more days. The primary endpoint was change from baseline (CFB) in the 17-item Hamilton Rating Scale for Depression (HAMD-17) total score at Day 3. Among 425 patients in the full analysis set, CFB in HAMD-17 total score at Day 3 was significantly improved with zuranolone+ADT vs placebo+ADT (least squares mean [standard error], -8.9 [0.39] vs -7.0 [0.38]; p = 0.0004). The majority of patients receiving zuranolone+ADT that experienced treatment-emergent adverse events (TEAEs) reported mild or moderate events. The most common TEAEs present in ≥10% of patients in either zuranolone+ADT or placebo+ADT groups were somnolence, dizziness, headache, and nausea. These results demonstrate that zuranolone+ADT provided more rapid improvement in depressive symptoms compared with placebo+ADT in patients with MDD, with a safety profile consistent with previous studies. Clinical trial registration: ClinicalTrials.gov identifier: NCT04476030.

Mitochondrial might: powering the peripartum for risk and resilience

The peripartum period, characterized by dynamic hormonal shifts and physiological adaptations, has been recognized as a potentially vulnerable period for the development of mood disorders such as postpartum depression (PPD). Stress is a well-established risk factor for developing PPD and is known to modulate mitochondrial function. While primarily known for their role in energy production, mitochondria also influence processes such as stress regulation, steroid hormone synthesis, glucocorticoid response, GABA metabolism, and immune modulation - all of which are crucial for healthy pregnancy and relevant to PPD pathology. While mitochondrial function has been implicated in other psychiatric illnesses, its role in peripartum stress and mental health remains largely unexplored, especially in relation to the brain. In this review, we first provide an overview of mitochondrial involvement in processes implicated in peripartum mood disorders, underscoring their potential role in mediating pathology. We then discuss clinical and preclinical studies of mitochondria in the context of peripartum stress and mental health, emphasizing the need for better understanding of this relationship. Finally, we propose mitochondria as biological mediators of resilience to peripartum mood disorders.

New insights on the potential effect of progesterone in Covid-19: Anti-inflammatory and immunosuppressive effects

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a pandemic disease caused by severe acute respiratory syndrome CoV type 2 (SARS-CoV-2). COVID-19 is higher in men than women and sex hormones have immune-modulator effects during different viral infections, including SARS-CoV-2 infection. One of the essential sex hormones is progesterone (P4).

AIMS

This review aimed to reveal the association between P4 and Covid-19.

RESULTS AND DISCUSSION

The possible role of P4 in COVID-19 could be beneficial through the modulation of inflammatory signaling pathways, induction of the release of anti-inflammatory cytokines, and inhibition release of pro-inflammatory cytokines. P4 stimulates skew of naïve T cells from inflammatory Th1 toward anti-inflammatory Th2 with activation release of anti-inflammatory cytokines, and activation of regulatory T cells (Treg) with decreased interferon-gamma production that increased during SARS-CoV-2 infection. In addition, P4 is regarded as a potent antagonist of mineralocorticoid receptor (MR), it could reduce MRs that were activated by stimulated aldosterone from high AngII during SARS-CoV-2. P4 active metabolite allopregnanolone is regarded as a neurosteroid that acts as a positive modulator of γ-aminobutyric acid (GABAA ) so it may reduce neuropsychiatric manifestations and dysautonomia in COVID-19 patients.

CONCLUSION

Taken together, the anti-inflammatory and immunomodulatory properties of P4 may improve central and peripheral complications in COVID-19.

Role of PPAR-Allopregnanolone Signaling in Behavioral and Inflammatory Gut-Brain Axis Communications

The gut microbiome regulates emotional behavior, stress responses, and inflammatory processes by communicating with the brain. How and which neurobiological mediators underlie this communication remain poorly understood. PPAR-α (peroxisome proliferator-activated receptor α), a transcription factor susceptible to epigenetic modifications, regulates pathophysiological functions, including metabolic syndrome, inflammation, and behavior. Mood disorders, inflammatory processes, and obesity are intertwined phenomena that are associated with low blood concentrations of the anti-inflammatory and "endogenous tranquilizer" neurosteroid allopregnanolone and poor PPAR-α function. Stress and consumption of obesogenic diets repress PPAR function in brain, enterocytes, lipocytes, and immune modulatory cells favoring inflammation, lipogenesis, and mood instability. Conversely, micronutrients and modulators of PPAR-α function improve microbiome composition, dampen systemic inflammation and lipogenesis, and improve anxiety and depression. In rodent stress models of anxiety and depression, PPAR activation normalizes both PPAR-α expression downregulation and decreased allopregnanolone content and ameliorates depressive-like behavior and fear responses. PPAR-α is known to regulate metabolic and inflammatory processes activated by short-chain fatty acids; endocannabinoids and congeners, such as N-palmitoylethanolamide, drugs that treat dyslipidemias; and micronutrients, including polyunsaturated fatty acids. Both PPAR-α and allopregnanolone are abundantly expressed in the colon, and they exert potent anti-inflammatory actions by blocking the toll-like receptor-4-nuclear factor-κB pathway in peripheral immune cells, neurons, and glia. The perspective that PPAR-α regulation in the colon by gut microbiota or metabolites influences central allopregnanolone content after trafficking to the brain, thereby serving as a mediator of gut-brain axis communications, is examined in this review.

Neurosteroid Receptor Modulators for Treating Traumatic Brain Injury

Traumatic brain injury (TBI) triggers wide-ranging pathology that impacts multiple biochemical and physiological systems, both inside and outside the brain. Functional recovery in patients is impeded by early onset brain edema, acute and chronic inflammation, delayed cell death, and neurovascular disruption. Drug treatments that target these deficits are under active development, but it seems likely that fully effective therapy may require interruption of the multiplicity of TBI-induced pathological processes either by a cocktail of drug treatments or a single pleiotropic drug. The complex and highly interconnected biochemical network embodied by the neurosteroid system offers multiple options for the research and development of pleiotropic drug treatments that may provide benefit for those who have suffered a TBI. This narrative review examines the neurosteroids and their signaling systems and proposes directions for their utility in the next stage of TBI drug research and development.

Neurosteroids and translocator protein 18 kDa (TSPO) in depression: implications for synaptic plasticity, cognition, and treatment options

There is need for novel fast acting treatment options in affective disorders. 3α-reduced neurosteroids such as allopregnanolone are powerful positive allosteric modulators of GABAA 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 GABAA 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.

GABAA receptors as targets for treating affective and cognitive symptoms of depression

In the past 20 years, our understanding of the pathophysiology of depression has evolved from a focus on an imbalance of monoaminergic neurotransmitters to a multifactorial picture including an improved understanding of the role of glutamatergic excitatory and GABAergic inhibitory neurotransmission. FDA-approved treatments targeting the glutamatergic [esketamine for major depressive disorder (MDD)] and GABAergic (brexanolone for peripartum depression) systems have become available. This review focuses on the GABAA receptor (GABAAR) system as a target for novel antidepressants and discusses the mechanisms by which modulation of δ-containing GABAARs with neuroactive steroids (NASs) or of α5-containing GABAARs results in antidepressant or antidepressant-like actions and discusses clinical data on NASs. Moreover, a potential mechanism by which α5-GABAAR-positive allosteric modulators (PAMs) may improve cognitive deficits in depression is presented.

Expediting the drug discovery for ideal leads against SARS-CoV-2 via molecular docking of repurposed drugs

SARS-CoV-2, the novel coronavirus spreading worldwide urges the need to repurpose drugs that can quickly enter clinical trials to combat the on-going global pandemic. A cluster of proteins are encoded for by the viral genome, each assuming a critical role in pathogen endurance inside the host. To handle the adverse circumstances, robust virtual strategies such as repurposing are coming to the fore due to being economical, efficient and rapid. Five FDA approved repurposed drugs proposed to act as inhibitors by targeting SARS-CoV-2 were used for initial evaluation via molecular docking. Moreover, a comparative analysis of the selected SARS-CoV-2 proteins against five ligands (Clemizole hydrochloride, Exemestane, Nafamostat, Pregnenolone and Umifenovir) was designed. In this regard, non-structural proteins (nsp3, nsp5, nsp10, nsp12 and nsp15), structural proteins (Spike, Nucleocapsid protein) and accessory proteins (ORF 3a, ORF 7a and ORF 9 b) were selected. Here, we aim to expedite the search for a potential drug from the five FDA approved repurposing drugs already in use for treatment of multiple diseases. Based on docking analysis, Umifenovir and Pregnenolone are suggested to show potential inhibitory effects against most of the SARS-CoV-2 proteins. These drugs are noteworthy since they exhibit high binding towards target proteins and should be used as lead compounds towards in vitro and in vivo studies.Communicated by Ramaswamy H. Sarma.

The influence of COVID-19 on colorectal cancer was investigated using bioinformatics and systems biology techniques

Introduction

Coronavirus disease 2019 (COVID-19) is a global pandemic and highly contagious, posing a serious threat to human health. Colorectal cancer (CRC) is a risk factor for COVID-19 infection. Therefore, it is vital to investigate the intrinsic link between these two diseases.

Methods

In this work, bioinformatics and systems biology techniques were used to detect the mutual pathways, molecular biomarkers, and potential drugs between COVID-19 and CRC.

Results

A total of 161 common differentially expressed genes (DEGs) were identified based on the RNA sequencing datasets of the two diseases. Functional analysis was performed using ontology keywords, and pathway analysis was also performed. The common DEGs were further utilized to create a protein-protein interaction (PPI) network and to identify hub genes and key modules. The datasets revealed transcription factors-gene interactions, co-regulatory networks with DEGs-miRNAs of common DEGs, and predicted possible drugs as well. The ten predicted drugs include troglitazone, estradiol, progesterone, calcitriol, genistein, dexamethasone, lucanthone, resveratrol, retinoic acid, phorbol 12-myristate 13-acetate, some of which have been investigated as potential CRC and COVID-19 therapies.

Discussion

By clarifying the relationship between COVID-19 and CRC, we hope to provide novel clues and promising therapeutic drugs to treat these two illnesses.

Divergent Transcriptomic Effects of Allopregnanolone in Postpartum Depression

Brexanolone, a formulation of the neurosteroid allopregnanolone (ALLO), is approved for treating postpartum depression (PPD) and is being investigated for therapeutic efficacy across numerous neuropsychiatric disorders. Given ALLO's beneficial effects on mood in women with PPD compared to healthy control women, we sought to characterize and compare the cellular response to ALLO in women with (n = 9) or without (n = 10, i.e., Controls) past PPD, utilizing our previously established patient-derived lymphoblastoid cell lines (LCLs). To mimic in vivo PPD ALLO-treatment, LCLs were exposed to ALLO or DMSO vehicle for 60 h and RNA-sequenced to detect differentially expressed genes (DEGs, pnominal < 0.05). Between ALLO-treated Control and PPD LCLs, 269 DEGs were identified, including Glutamate Decarboxylase 1 (GAD1), which was decreased 2-fold in PPD. Network analysis of PPD:ALLO DEGs revealed enriched terms related to synaptic activity and cholesterol biosynthesis. Within-diagnosis analyses (i.e., DMSO vs. ALLO) detected 265 ALLO-induced DEGs in Control LCLs compared to only 98 within PPD LCLs, with just 11 DEGs overlapping. Likewise, the gene ontologies underlying ALLO-induced DEGs in PPD and Control LCLs were divergent. These data suggest that ALLO may activate unique and opposing molecular pathways in women with PPD, which may be tied to its antidepressant mechanism.

Biomarkers and treatments for mood disorders encompassing the neurosteroid and endocannabinoid systems

Mood disorders, including major depressive disorder, postpartum depression, post-traumatic stress disorder and suicidality are highly prevalent, associated with a significant economic burden, and remain poorly diagnosed and poorly treated psychiatric conditions. In part, this may result from the lack of biomarkers that can guide precision medicine with individualized treatments for millions of individuals who suffer these debilitating conditions worldwide. While several biomarker candidates have been proposed for mood disorders, none has been implemented in clinical practice and the treatment still relies in the prescription of selective serotonin reuptake inhibitors that shows mixed efficacy and significant side effects. Both neurosteroid biosynthesis and the endocannabinoid system have recently provided evidence for pharmacological targets to improve mood symptoms and the neuroactive steroid allopregnanolone has recently been approved by the USA Food and Drug Administration for the treatment of post-partum depression. Clinical studies also show efficacy for the management of major depression and more studies are being conducted to study efficacy in post-traumatic stress disorder. Likewise, the endocannabinoid-like modulator, N-palmioyl ethanolamide (PEA) has shown efficacy in the treatment of major depression and bipolar disorder. While these new agents are coming forward in the field of neuropsychopharmacology as a new generation of fast-acting antidepressants, the hypothesis of whether their deficits underlying mood disorders could constitute valid predictive biomarkers to facilitate diagnosis and treatment of these conditions is under consideration.

Heterogeneity in major depressive disorder: The need for biomarker-based personalized treatments

Major Depressive Disorder (MDD) or depression is a pathological mental condition affecting millions of people worldwide. Identification of objective biological markers of depression can provide for a better diagnostic and intervention criteria; ultimately aiding to reduce its socioeconomic health burden. This review provides a comprehensive insight into the major biomarker candidates that have been implicated in depression neurobiology. The key biomarker categories are covered across all the "omics" levels. At the epigenomic level, DNA-methylation, non-coding RNA and histone-modifications have been discussed in relation to depression. The proteomics system shows great promise with inflammatory markers as well as growth factors and neurobiological alterations within the endocannabinoid system. Characteristic lipids implicated in depression together with the endocrine system are reviewed under the metabolomics section. The chapter also examines the novel biomarkers for depression that have been proposed by studies in the microbiome. Depression affects individuals differentially and explicit biomarkers identified by robust research criteria may pave the way for better diagnosis, intervention, treatment, and prediction of treatment response.

Many or too many progesterone membrane receptors? Clinical implications

Several receptors for nongenomically initiated actions of progesterone (P4) exist, namely membrane-associated P4 receptors (MAPRs), membrane progestin receptors (mPRs), receptors for neurosteroids [GABA_A receptor (GABA_AR), NMDA receptor, sigma-1 and -2 receptors (S1R/S2R)], the classical genomic P4 receptor (PGR), and α/β hydrolase domain-containing protein 2 (ABHD2). Two drugs related to this field have been approved: brexanolone (Zulresso™) for the treatment of postpartum depression, and ganaxolone (Ztalmy™) for the treatment of CDKL5 deficiency disorder. Both are derivatives of P4 and target the GABA_AR. Several other indications are in clinical testing. CT1812 (Elayta™) is also being tested for the treatment of Alzheimer's disease (AD) in Phase 2 clinical trials, targeting the P4 receptor membrane component 1 (PGRMC1)/S2R complex. In this Review, we highlight emerging knowledge on the mechanisms of nongenomically initiated actions of P4 and its derivatives.

Positive allosteric modulators of GABAA receptor restore chloride current from blockade by competitive antagonists in a ligand-dependent manner

γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter. GABA receptor type A (GABAAR) possesses binding sites for a large group of pharmacological agents which are supposed to interact allosterically with each other. The aim of this work was to study the interaction between the positive allosteric modulators (PAMs) and the competitive antagonists of GABAARs. The GABA-induced chloride current (IGABA) was measured in isolated Purkinje cells of rat cerebellum using the patch-clamp technique. PAMs, neurosteroid allopregnanolone (Allo) and zolpidem (Zolp), a drug that positively modulates the GABAAR through interaction with the benzodiazepine (BDZ) site, doubled the IGABA amplitude in the control solution. Competitive antagonist of GABAARs, bicuculline (Bic, 5 µM) blocked the IGABA by 90%. The addition of 1 μM Allo or 0.5 µM Zolp to the Bic solution caused an unblocking effect, so that the IGABA amplitude increased 10 and 4 times from control value, correspondingly. This unblocking effect developed slowly, as evidenced by a threefold increase in the current rise time. Competitive antagonist of GABAARs, gabazine (GBZ, 0.5 µM) blocked the IGABA by 87%. The addition of 1 μM Allo to the GBZ solution caused an unblocking effect, so that the IGABA amplitude increased 7-fold. However, the addition of 0.5 µM Zolp to the GBZ solution did not cause an unblocking effect. So, Allo appeared to have a stronger unblocking potential than Zolp, and Bic binding site showed a higher sensitivity to the action of unblocking PAMs than GBZ binding site. The results indicate for the first time the existence of an allosteric relationship between the sites binding PAMs and the competitive antagonists of GABAAR.

The Allopregnanolone Response to Acute Stress in Females: Preclinical and Clinical Studies

The neuroactive steroid allopregnanolone ((3α,5α)-3-hydroxypregnan-20-one or 3α,5α-THP) plays a key role in the response to stress, by normalizing hypothalamic-pituitary-adrenal (HPA) axis function to restore homeostasis. Most studies have been conducted on male rats, and little is known about the allopregnanolone response to stress in females, despite that women are more susceptible than men to develop emotional and stress-related disorders. Here, we provide an overview of animal and human studies examining the allopregnanolone responses to acute stress in females in the context of stress-related neuropsychiatric diseases and under the different conditions that characterize the female lifespan associated with the reproductive function. The blunted allopregnanolone response to acute stress, often observed in female rats and women, may represent one of the mechanisms that contribute to the increased vulnerability to stress and affective disorders in women under the different hormonal fluctuations that occur throughout their lifespan. These studies highlight the importance of targeting neuroactive steroids as a therapeutic approach for stress-related disorders in women.

mPR-Specific Actions Influence Maintenance of the Blood–Brain Barrier (BBB)

Cerebral cavernous malformations (CCMs) are characterized by abnormally dilated intracranial microvascular sinusoids that result in increased susceptibility to hemorrhagic stroke. It has been demonstrated that three CCM proteins (CCM1, CCM2, and CCM3) form the CCM signaling complex (CSC) to mediate angiogenic signaling. Disruption of the CSC will result in hemorrhagic CCMs, a consequence of compromised blood–brain barrier (BBB) integrity. Due to their characteristically incomplete penetrance, the majority of CCM mutation carriers (presumed CCM patients) are largely asymptomatic, but when symptoms occur, the disease has typically reached a clinical stage of focal hemorrhage with irreversible brain damage. We recently reported that the CSC couples both classic (nuclear; nPRs) and nonclassic (membrane; mPRs) progesterone (PRG)-receptors-mediated signaling within the CSC-mPRs-PRG (CmP) signaling network in nPR(−) breast cancer cells. In this report, we demonstrate that depletion of any of the three CCM genes or treatment with mPR-specific PRG actions (PRG/mifepristone) results in the disruption of the CmP signaling network, leading to increased permeability in the nPR(−) endothelial cells (ECs) monolayer in vitro. Finally, utilizing our in vivo hemizygous Ccm mutant mice models, we demonstrate that depletion of any of the three CCM genes, in combination with mPR-specific PRG actions, is also capable of leading to defective homeostasis of PRG in vivo and subsequent BBB disruption, allowing us to identify a specific panel of etiological blood biomarkers associated with BBB disruption. To our knowledge, this is the first report detailing the etiology to predict the occurrence of a disrupted BBB, an indication of early hemorrhagic events.

Pregnane neurosteroids exert opposite effects on GABA and glycine-induced chloride current in isolated rat neurons

The ability of endogenous neurosteroids (NSs) with pregnane skeleton modified at positions C-3 and C-5 to modulate the functional activity of inhibitory glycine receptors (GlyR) and ionotropic ɣ-aminobutyric acid receptors (GABA_A R) was estimated. The glycine and GABA-induced chloride current (I_Gly and I_GABA ) were measured in isolated pyramidal neurons of the rat hippocampus and in isolated rat cerebellar Purkinje cells, respectively. Our experiments demonstrated that pregnane NSs affected I_GABA and I_Gly in a different manner. At low concentrations (up to 5 μM), tested pregnane NSs increased or did not change the peak amplitude of the I_GABA , but reduced the I_Gly by decreasing the peak amplitude and/or accelerating desensitization. Namely, allopregnanolone (ALLO), epipregnanolone (EPI), pregnanolone (PA), pregnanolone sulfate (PAS) and 5β-dihydroprogesterone (5β-DHP) enhanced the I_GABA in Purkinje cells. Dose-response curves plotted in the concentration range from 1 nM to 100 μM were smooth for EPI and 5β-DHP, but bell-shaped for ALLO, PA and PAS. The peak amplitude of the I_Gly was reduced by PA, PAS, and 5α- and 5β-DHP. In contrast, ALLO, ISO and EPI did not modulate it. Dose-response curves for the inhibition of the I_Gly peak amplitude were smooth for all active compounds. All NSs accelerated desensitization of the I_Gly . The dose-response relationship for this effect was smooth for ALLO, PA, PAS and 5β-DHP, but it was U-shaped for EPI, 5α-DHP and ISO. These results, together with our previous results on NSs with androstane skeleton, offer comprehensive overview for understanding the mechanisms of effects of NSs on I_Gly and I_GABA .

How hormonal contraceptives shape brain and behavior: A review of preclinical studies

Steroid hormones influence different aspects of brain function, including development, neurogenesis, neuronal excitability, and plasticity, thus affecting emotional states, cognition, sociality, and reward. In women, their levels fluctuate across the lifespan and through the reproductive stages but are also altered by exogenous administration of hormonal contraceptives (HC). HC are widely used by women throughout their fertile life both for contraceptive and therapeutic benefits. However, awareness of their effects on brain function and behavior is still poorly appreciated, despite the emerging evidence of their action at the level of the central nervous system. Here, we summarize results obtained in preclinical studies, mostly conducted in intact female rodents, aimed at investigating the neurobiological effects of HC. HC can alter neuroactive hormones, neurotransmitters, neuropeptides, as well as emotional states, cognition, social and sexual behaviors. Animal studies provide insights into the neurobiological effects of HC with the aim to improve women's health and well-being.

Pharmacological, Neurochemical, and Behavioral Mechanisms Underlying the Anxiolytic- and Antidepressant-like Effects of Flavonoid Chrysin

Chrysin (5,7-dihydroxyflavone) is a flavonoid isolated from plants, such as Passiflora coerulea, Passiflora incarnata, and Matricaria chamomilla. This natural molecule exerts diverse pharmacological effects, which includes antioxidant, anti-inflammatory, anti-cancer, neuroprotective, and anti-apoptotic effects. Additionally, in brain structures, such as the hippocampus, prefrontal cortex, raphe nucleus, and striatum, involved in the physiopathology of anxiety and depression disorders, several neuropharmacological activities, including the activation of neurotransmitter systems (GABAergic, serotonergic, dopaminergic, and noradrenergic), neurotrophic factors, such as brain-derived neurotrophic factor and the nerve growth factor, and some signaling pathways are affected. The results showed that the anxiolytic and antidepressant-like effects of chrysin occurs through its interaction with specific neurotransmitter systems, principally the GABAergic and the serotonergic, and activation of other neurotrophic factors. However, it is not possible to discard the antioxidant and anti-inflammatory activities of chrysin while producing its anxiolytic- and antidepressant-like effects. Although these results have been obtained principally from pre-clinical research, they consistently demonstrate the potential therapeutic use of flavonoid chrysin as an anxiolytic and antidepressant agent. Therefore, this flavonoid could be considered as a promising novel therapy for anxiety and depression disorders.

Allopregnanolone suppresses glioblastoma survival through decreasing DPYSL3 and S100A11 expression

Allopregnanolone (allo) is a physiological regulator of neuronal activity that treats multiple neurological disorders. Allo penetrates the blood-brain barrier with very high efficiency, implying that allo can treat CNS-related diseases, including glioblastoma (GBM), which always recurs after standard therapy. Hence, this study aimed to determine whether allo has a therapeutic effect on GBM. We found that allo enhanced temozolomide (TMZ)-suppressed cell survival and proliferation of TMZ-resistant cells. In particular, allo enhanced TMZ-inhibited cell migration and TMZ-induced apoptosis. Additionally, allo strongly induced DNA damage characterized by γH2Ax. Furthermore, quantitative proteomic analysis, iTRAQ, showed that allo significantly decreased the levels of DPYSL3, S100A11, and S100A4, reflecting the poor prognosis of patients with GBM confirmed by differential gene expression and survival analysis. Moreover, single-cell RNA-Seq revealed that S100A11, expressed in malignant cells, oligodendrocytes, and macrophages, was significantly associated with immune cell infiltration. Furthermore, overexpression of DPYSL3 or S100A11 prevented allo-induced cell death. In conclusion, allo suppresses GBM cell survival by decreasing DPYSL3/S100A11 expression and inducing DNA damage.

Bioinformatics and System Biology Approach to Identify the Influences of COVID-19 on Rheumatoid Arthritis

Background

Severe coronavirus disease 2019 (COVID -19) has led to a rapid increase in mortality worldwide. Rheumatoid arthritis (RA) was a high-risk factor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, whereas the molecular mechanisms underlying RA and CVOID-19 are not well understood. The objectives of this study were to analyze potential molecular mechanisms and identify potential drugs for the treatment of COVID-19 and RA using bioinformatics and a systems biology approach.

Methods

Two Differentially expressed genes (DEGs) sets extracted from GSE171110 and GSE1775544 datasets were intersected to generate common DEGs, which were used for functional enrichment, pathway analysis, and candidate drugs analysis.

Results

A total of 103 common DEGs were identified in the two datasets between RA and COVID-19. A protein-protein interaction (PPI) was constructed using various combinatorial statistical methods and bioinformatics tools. Subsequently, hub genes and essential modules were identified from the PPI network. In addition, we performed functional analysis and pathway analysis under ontological conditions and found that there was common association between RA and progression of COVID-19 infection. Finally, transcription factor-gene interactions, protein-drug interactions, and DEGs-miRNAs coregulatory networks with common DEGs were also identified in the datasets.

Conclusion

We successfully identified the top 10 hub genes that could serve as novel targeted therapy for COVID-19 and screened out some potential drugs useful for COVID-19 patients with RA.

Allopregnanolone: The missing link to explain the effects of stress on tic exacerbation?

The neurosteroid allopregnanolone (3α-hydroxy-5α-pregnan-20-one; AP) elicits pleiotropic effects in the central nervous system, ranging from neuroprotective and anti-inflammatory functions to the regulation of mood and emotional responses. Several lines of research show that the brain rapidly produces AP in response to acute stress to reduce the allostatic load and enhance coping. These effects not only are likely mediated by GABA_A receptor activation but also result from the contributions of other mechanisms, such as the stimulation of membrane progesterone receptors. In keeping with this evidence, AP has been shown to exert rapid, potent antidepressant properties and has been recently approved for the therapy of moderate-to-severe postpartum depression. In addition to depression, emerging evidence points to the potential of AP as a therapy for other neuropsychiatric disorders, including anxiety, seizures, post-traumatic stress disorder and cognitive problems. Although this evidence has spurred interest in further therapeutic applications of AP, some investigations suggest that this neurosteroid may also be associated with adverse events in specific disorders. For example, our group has recently documented that AP increases tic-like manifestations in several animal models of tic disorders; furthermore, our results indicate that inhibiting AP synthesis and signalling reduces the exacerbation of tic severity associated with acute stress. Although the specific mechanisms of these effects remain partially elusive, our findings point to the possibility that the GABAergic activation by AP may also lead to disinhibitory effects, which could interfere with the ability of patients to suppress their tics. Future studies will be necessary to verify whether these mechanisms may apply to other externalising manifestations, such as impulse-control problems and manic symptoms.

Superior mesenteric ganglion neural modulation of ovarian angiogenesis, apoptosis and proliferation by the neuroactive steroid allopregnanolone

Allopregnanolone (ALLO), a potent neuroactive steroid, is synthesized and active in the peripheral nervous system. Previous studies have shown that ALLO participates in the central regulation of reproduction with effects on ovarian physiology, although there is little evidence for its ability to modulate peripheral tissues. The present study aimed to determine whether ALLO, administered to an ex vivo system that comprises the superior mesenteric ganglion (SMG), the ovarian nervous plexus (ONP) and the ovary (O), or to the denervated ovary (DO), was able to modify ovarian apoptosis, proliferation and angiogenesis. For this purpose, the SMG-ONP-O system and DO were incubated during 120 min at 37°C, in the presence of two ALLO doses (0.06 µm and 6 µm). The intrinsic and extrinsic pathways of apoptosis were analyzed. Incubation of the SMG-ONP-O system with ALLO 0.06 µm led to an increase in the BAX/BCL-2 ratio and a reduction of FAS-L mRNA levels. ALLO 6 µm induced a decrease of FAS-L levels. Incubation of DO with ALLO 0.06 µm reduced FAS-L, whereas ALLO 6 µm significantly increased it. Cyclin D1 mRNA was measured to evaluate proliferation. Treatment with ALLO 6 µm increased proliferation in both SMG-ONP-O and DO. ALLO 0.06 µm produced an increase of Cyclin D1 in DO only. Administration of either ALLO dose led to a higher ovarian expression of vascular endothelial growth factor in the SMG-ONP-O system, but a lower one in the DO system. ALLO 6 µm induced ovarian sensitization to GABA by increasing GABA_A receptor expression. In conclusion, ALLO participates in the peripheral neural modulation of ovarian physiology. It can also interact directly with the ovarian tissue, modulating key mechanisms involved in normal and pathological processes in a dose-dependent manner.

GABAA/Benzodiazepine Receptor Complex in the Dorsal Hippocampus Mediates the Effects of Chrysin on Anxiety-Like Behaviour in Female Rats

Systemic injections of the flavonoid chrysin (5,7-dihydroxyflavone) exert anxiolytic-like effects in ovariectomised and cycling female rats through actions on gamma-aminobutyric acid-A (GABA_A) receptors; however, it is unknown if chrysin directly acts on brain structures that are involved in regulating emotional processes, such as the hippocampus. The present study evaluated the effects of intrahippocampal microinjections of 0.25, 0.5, and 1 μg of chrysin on anxiety-like behaviour in the elevated plus maze (EPM) and locomotor activity test (LAT) in female rats in proestrus and dioestrus. Similar doses of the neurosteroid allopregnanolone were used as a reference GABAergic anxiolytic drug. The participation of the GABA_A/benzodiazepine receptor complex was evaluated by administering the antagonists picrotoxin, bicuculline and flumazenil. In proestrus, 0.5 and 1 μg of chrysin and allopregnanolone induced anxiogenic-like behaviour. In dioestrus, chrysin, and allopregnanolone (0.5 μg) induced anxiolytic-like effects. Picrotoxin, bicuculline and flumazenil prevented the effects of chrysin and allopregnanolone in both proestrus and dioestrus. None of the treatments significantly affected locomotor activity. These results indicate that the GABA_A/benzodiazepine receptor complex in the dorsal hippocampus regulates the effects of chrysin on anxiety-like behaviour, similar to the actions of allopregnanolone. The divergent effects of treatments across the oestrous cycle phases suggest complex interactions between GABA_A receptors and compounds with an anxiolytic potential.

Neurosteroid Activation of GABA-A Receptors: A Potential Treatment Target for Symptoms in Primary Biliary Cholangitis?

Background and Aims

A third of patients with primary biliary cholangitis (PBC) experience poorly understood cognitive symptoms, with a significant impact on quality of life (QOL), and no effective medical treatment. Allopregnanolone, a neurosteroid, is a positive allosteric modulator of gamma-aminobutyricacid-A (GABA-A) receptors, associated with disordered mood, cognition, and memory. This study explored associations between allopregnanolone and a disease-specific QOL scoring system (PBC-40) in PBC patients.

Method

Serum allopregnanolone levels were measured in 120 phenotyped PBC patients and 40 age and gender-matched healthy controls. PBC subjects completed the PBC-40 at recruitment. Serum allopregnanolone levels were compared across PBC-40 domains for those with none/mild symptoms versus severe symptoms.

Results

There were no overall differences in allopregnanolone levels between healthy controls (median = 0.03 ng/ml (IQR = 0.025)) and PBC patients (0.031 (0.42), p = 0.42). Within the PBC cohort, higher allopregnanolone levels were observed in younger patients (r (120) = -0.53, p < 0.001) but not healthy controls (r (39) = -0.21, p = 0.21). Allopregnanolone levels were elevated in the PBC-40 domains, cognition (u = 1034, p = 0.02), emotional (u = 1374, p = 0.004), and itch (u = 795, p = 0.03). Severe cognitive symptoms associated with a younger age: severe (50 (12)) vs. none (60 (13); u = 423 p = 0.001).

Conclusion

Elevated serum allopregnanolone is associated with severe cognitive, emotional, and itch symptoms in PBC, in keeping with its known action on GABA-A receptors. Existing novel compounds targeting allopregnanolone could offer new therapies in severely symptomatic PBC, satisfying a significant unmet need.

Tonic GABAA Receptor-Mediated Currents of Human Cortical GABAergic Interneurons Vary Amongst Cell Types

Persistent anion conductances through GABAA receptors (GABAARs) are important modulators of neuronal excitability. However, it is currently unknown how the amplitudes of these currents vary among different cell types in the human neocortex, particularly among diverse GABAergic interneurons. We have recorded 101 interneurons in and near layer 1 from cortical tissue surgically resected from both male and female patients, visualized 84 of them and measured tonic GABAAR currents in 48 cells with an intracellular [Cl-] of 65 mm and in the presence of 5 μm GABA. We compare these tonic currents among five groups of interneurons divided by firing properties and four types of interneuron defined by axonal distributions; rosehip, neurogliaform, stalked-bouton, layer 2-3 innervating and a pool of other cells. Interestingly, the rosehip cell, a type of interneuron only described thus far in human tissue, and layer 2-3 innervating cells exhibit larger tonic currents than other layer 1 interneurons, such as neurogliaform and stalked-bouton cells; the latter two groups showing no difference. The positive allosteric modulators of GABAARs allopregnanolone and DS2 also induced larger current shifts in the rosehip and layer 2-3 innervating cells, consistent with higher expression of the δ subunit of the GABAAR in these neurons. We have also examined how patient parameters, such as age, seizures, type of cancer and anticonvulsant treatment may alter tonic inhibitory currents in human neurons. The cell type-specific differences in tonic inhibitory currents could potentially be used to selectively modulate cortical circuitry.SIGNIFICANCE STATEMENT Tonic currents through GABAA receptors (GABAARs) are a potential therapeutic target for a number of neurologic and psychiatric conditions. Here, we show that these currents in human cerebral cortical GABAergic neurons display cell type-specific differences in their amplitudes which implies differential modulation of their excitability. Additionally, we examine whether the amplitudes of the tonic currents measured in our study show any differences between patient populations, finding some evidence that age, seizures, type of cancer, and anticonvulsant treatment may alter tonic inhibition in human tissue. These results advance our understanding of how pathology affects neuronal excitability and could potentially be used to selectively modulate cortical circuitry.

New insights into the functions of progesterone receptor (PR) isoforms and progesterone signaling

Progesterone, the ovarian steroid hormone, regulates a plentitude of biological processes in tissues ranging from the brain to bones. Recognizing the role of progesterone and its receptors in physiological processes and maladies can prevent and treat various diseases. Apart from its physiological functions, its role in developing diseases, especially breast cancer, is a recent topic of deliberation. There exists conflicting experimental and epidemiological evidence linking progesterone to breast cancer. This review tries to describe the physiological functions of progesterone and its receptors, genomic and non-genomic signaling, splice variants, and a different aspect of progesterone signaling. Furthermore, we seek to address or attempt to discuss the following pertinent questions on steroid hormone signaling; How does progesterone influence breast cancer progression? How does it change the molecular pathways in breast cancer with different receptor statuses, the specific role of each isoform, and how does the ER/and PR ratio affect progesterone signaling?

PPAR-α Hypermethylation in the Hippocampus of Mice Exposed to Social Isolation Stress Is Associated with Enhanced Neuroinflammation and Aggressive Behavior

Social behavioral changes, including social isolation or loneliness, increase the risk for stress-related disorders, such as major depressive disorder, posttraumatic stress disorder (PTSD), and suicide, which share a strong neuroinflammatory etiopathogenetic component. The peroxisome-proliferator activated receptor (PPAR)-α, a newly discovered target involved in emotional behavior regulation, is a ligand-activated nuclear receptor and a transcription factor that, following stimulation by endogenous or synthetic ligands, may induce neuroprotective effects by modulating neuroinflammation, and improve anxiety and depression-like behaviors by enhancing neurosteroid biosynthesis. How stress affects epigenetic mechanisms with downstream effects on inflammation and emotional behavior remains poorly understood. We studied the effects of 4-week social isolation, using a mouse model of PTSD/suicide-like behavior, on hippocampal PPAR-α epigenetic modification. Decreased PPAR-α expression in the hippocampus of socially isolated mice was associated with increased levels of methylated cytosines of PPAR-α gene CpG-rich fragments and deficient neurosteroid biosynthesis. This effect was associated with increased histone deacetylases (HDAC)1, methyl-cytosine binding protein (MeCP)2 and decreased ten-eleven translocator (TET)2 expression, which favor hypermethylation. These alterations were associated with increased TLR-4 and pro-inflammatory markers (e.g., TNF-α,), mediated by NF-κB signaling in the hippocampus of aggressive mice. This study contributes the first evidence of stress-induced brain PPAR-α epigenetic regulation. Social isolation stress may constitute a risk factor for inflammatory-based psychiatric disorders associated with neurosteroid deficits, and targeting epigenetic marks linked to PPAR-α downregulation may offer a valid therapeutic approach.

Epipregnanolone as a Positive Modulator of GABAA Receptor in Rat Cerebellar and Hippocampus Neurons

Epipregnanolone (3β-hydroxy-5β-pregnan-20-one, Epi) is an endogenous steroid with important physiological effects and high affinity for GABA_A receptors. The effect of Epi on GABA-induced chloride current (I_GABA) in native neurons has hardly been studied. In this work, we studied the influence of Epi on the I_GABA in the Purkinje cells of rat cerebellum and pyramidal neurons of rat hippocampus with the patch clamp technique. We showed that Epi is a positive modulator of the I_GABA with EC₅₀ of 5.7 µM in Purkinje cells and 9.3 µM in hippocampal neurons. Epi-induced potentiation of the I_GABA was more potent at low vs. high GABA concentrations. Isopregnanolone (3β-hydroxy-5α-pregnan-20-one, Iso) counteracted Epi, reducing its potentiating effect by 2–2.3 times. Flumazenil, a nonsteroidal GABA_A receptor antagonist, does not affect the Epi-induced potentiation. Comparison of the potentiating effects of Epi and allopregnanolone (3α-hydroxy-5α-pregnan-20-one, ALLO) showed that ALLO is, at least, a four times more potent positive modulator than Epi. The combined application of ALLO and Epi showed that the effects of these two steroids are not additive. We conclude that Epi has a dual effect on the I_GABA increasing the current in the control solution and decreasing the stimulatory effect of ALLO.

The Role of HPA Axis and Allopregnanolone on the Neurobiology of Major Depressive Disorders and PTSD

Under stressful conditions, the hypothalamic-pituitary-adrenal (HPA) axis acts to promote transitory physiological adaptations that are often resolved after the stressful stimulus is no longer present. In addition to corticosteroids (e.g., cortisol), the neurosteroid allopregnanolone (3α,5α-tetrahydroprogesterone, 3α-hydroxy-5α-pregnan-20-one) participates in negative feedback mechanisms that restore homeostasis. Chronic, repeated exposure to stress impairs the responsivity of the HPA axis and dampens allopregnanolone levels, participating in the etiopathology of psychiatric disorders, such as major depressive disorder (MDD) and post-traumatic stress disorder (PTSD). MDD and PTSD patients present abnormalities in the HPA axis regulation, such as altered cortisol levels or failure to suppress cortisol release in the dexamethasone suppression test. Herein, we review the neurophysiological role of allopregnanolone both as a potent and positive GABAergic neuromodulator but also in its capacity of inhibiting the HPA axis. The allopregnanolone function in the mechanisms that recapitulate stress-induced pathophysiology, including MDD and PTSD, and its potential as both a treatment target and as a biomarker for these disorders is discussed.

Brexanolone to Treat Postpartum Depression in Adult Women

ZULRESSO (Brexanolone) is a novel FDA-approved treatment for moderate-to-severe postpartum depression. Postpartum depression may be diagnosed in women experiencing depressive symptoms which can manifest as cognitive, behavioral, or emotional disturbances as early as the third trimester to 4 weeks following delivery. The efficacy of brexanolone suggests that neurosteroids such as allopregnanolone are important to treat PPD. However, it is currently unclear if brexanolone provides lasting relief of depressive symptoms at or beyond 30 days following administration. Further studies are necessary to make this determination.

Maternal Distress and Offspring Neurodevelopment: Challenges and Opportunities for Pre-clinical Research Models

Pre-natal exposure to acute maternal trauma or chronic maternal distress can confer increased risk for psychiatric disorders in later life. Acute maternal trauma is the result of unforeseen environmental or personal catastrophes, while chronic maternal distress is associated with anxiety or depression. Animal studies investigating the effects of pre-natal stress have largely used brief stress exposures during pregnancy to identify critical periods of fetal vulnerability, a paradigm which holds face validity to acute maternal trauma in humans. While understanding these effects is undoubtably important, the literature suggests maternal stress in humans is typically chronic and persistent from pre-conception through gestation. In this review, we provide evidence to this effect and suggest a realignment of current animal models to recapitulate this chronicity. We also consider candidate mediators, moderators and mechanisms of maternal distress, and suggest a wider breadth of research is needed, along with the incorporation of advanced -omics technologies, in order to understand the neurodevelopmental etiology of psychiatric risk.

Neurosteroids and Neurotrophic Factors: What Is Their Promise as Biomarkers for Major Depression and PTSD?

Even though major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) are among the most prevalent and incapacitating mental illnesses in the world, their diagnosis still relies solely on the characterization of subjective symptoms (many of which are shared by multiple disorders) self-reported by patients. Thus, the need for objective measures that aid in the detection of and differentiation between psychiatric disorders becomes urgent. In this paper, we explore the potential of neurosteroids and neurotrophic proteins as biomarkers for MDD and PTSD. Circulating levels of the GABAergic neuroactive steroid, allopregnanolone, are diminished in MDD and PTSD patients, which corroborates the finding of depleted neurosteroid levels observed in animal models of these disorders. The neurotrophic protein, brain-derived neurotropic factor (BDNF), is also reduced in the periphery and in the brain of MDD patients and depressed-like animals that express lower neurosteroid levels. Although the role of BDNF in PTSD psychopathology seems less clear and merits more research, we propose a causal link between allopregnanolone levels and BDNF expression that could function as a biomarker axis for the diagnosis of both MDD and PTSD.

Allopregnanolone Decreases Evoked Dopamine Release Differently in Rats by Sex and Estrous Stage

Mesolimbic dopamine transmission is dysregulated in multiple psychiatric disorders, including addiction. Previous studies found that the endogenous GABAergic steroid (3α,5α)-3-hydroxy-5-pregnan-20-one (allopregnanolone) modulates dopamine levels in the nucleus accumbens and prefrontal cortex. As allopregnanolone is a potent positive allosteric modulator of GABA_A receptors, and GABA_A receptors can regulate dopamine release, we hypothesized that allopregnanolone would reduce phasic fluctuations in mesolimbic dopamine release that are important in learning and reward processing. We used fast-scan cyclic voltammetry in anesthetized female and male rats to measure dopamine release in the nucleus accumbens evoked by electrical stimulation of the ventral tegmental area, before and after administration of allopregnanolone. Allopregnanolone (7.5–25 mg/kg, IP) reduced evoked dopamine release in both male and female rats, compared to β-cyclodextrin vehicle. In males, all doses of allopregnanolone decreased dopamine transmission, with stronger effects at 15 and 25 mg/kg allopregnanolone. In females, 15 and 25 mg/kg allopregnanolone reduced dopamine release, while 7.5 mg/kg allopregnanolone was no different from vehicle. Since allopregnanolone is derived from progesterone, we hypothesized that high endogenous progesterone levels would result in lower sensitivity to allopregnanolone. Consistent with this, females in proestrus (high progesterone levels) were less responsive to allopregnanolone than females in other estrous cycle stages. Furthermore, 30 mg/kg progesterone reduced evoked dopamine release in males, similar to allopregnanolone. Our findings confirm that allopregnanolone reduces evoked dopamine release in both male and female rats. Moreover, sex and the estrous cycle modulated this effect of allopregnanolone. These results extend our knowledge about the pharmacological effects of neurosteroids on dopamine transmission, which may contribute to their therapeutic effects.