Search Results (59)

Background: Freeze tolerance is an uncommon but highly effective strategy that allows certain vertebrates to survive prolonged exposure to subzero temperatures in a frozen, ischemic state. While past studies have characterized the metabolic and biochemical adaptations involved, including cryoprotectant accumulation and metabolic rate suppression, the contribution of post-transcriptional gene regulation by microRNAs (miRNAs) remains largely unexplored. This study investigated freeze-responsive miRNAs in cardiac tissue of the gray tree frog, Dryophytes versicolor, to better understand the molecular mechanisms that support ischemic survival and tissue preservation. Methods: Adult frogs were subjected to controlled freezing at −2.5 °C, and cardiac tissue was collected from frozen and control animals. Total RNA was extracted and analyzed via small RNA sequencing to identify differentially expressed miRNAs, followed by target gene prediction and KEGG pathway enrichment analysis. Results: A total of 3 miRNAs were differentially expressed during freezing, with significant upregulation of miR-93-5p and let-7b-5p and downregulation of miR-4485-3p. Predicted targets of upregulated miRNAs included genes involved in immune signaling pathways (e.g., cytokine–cytokine receptor interaction), steroid hormone biosynthesis, and neuroactive ligand–receptor interaction, suggesting suppression of energetically costly signaling processes. Downregulation of miRNAs targeting cell cycle, insulin signaling, and WNT pathways indicates possible selective preservation of cytoprotective and repair functions. Conclusion: Overall, these results suggest that D. versicolor employs miRNA-mediated regulatory networks to support metabolic suppression, maintain essential signaling, and prevent damage during prolonged cardiac arrest. This work expands our understanding of freeze tolerance at the molecular level and may offer insights into biomedical strategies for cryopreservation and ischemia–reperfusion injury. Full article

Although opioids are effective in treating pain, they cause serious side effects. The use of regional anesthesia, although effective in the perioperative period, may not be suitable if mobility and lack of numbness is desired. Hence, there is a clear need for novel pain therapies. Low-voltage activated (T-type) calcium channels (Ca_V3.2 isoform) could be a promising therapeutic target for the development of novel pain therapies. Indeed, our published findings suggest that novel neuroactive steroid (NAS) analogs that modulate the activity of Ca_V3.2 channels have unique anti-nociceptive properties. However, the concern with current NASs appears to be their hypnotic/sedative properties, thus potentially hindering the future development of NASs for novel pain therapies. Hence, we developed a new line of NASs that are effective blockers of neuronal Ca_V3.2 channels in pain pathways while having more favorable pharmacodynamic properties, i.e., lack of sedative/hypnotic side effects. We present two promising novel analogs of NASs—B372 ((3β,5α,17β)-3-Hydroxyandrostan-17-carbonitrile) and YX23 ((3β,5α,17β)-3-Methoxyestran-17-ol). Using an in vitro approach, we show that B372 and YX23 are effective in blocking Ca_V3.2 channels. Using an in vivo approach, we show that they are effective anti-nociceptives in wild-type but not Ca_V3.2 knock-out mice. Importantly, we show that they lack sedative/hypnotic effects. Full article

Background: Finasteride, a 5α-reductase inhibitor commonly prescribed for androgenetic alopecia, has been linked to persistent adverse effects after discontinuation, known as post-finasteride syndrome (PFS). Symptoms include neurological, psychiatric, sexual, and gastrointestinal disturbances. Emerging evidence suggests that PFS may involve disruption of sex steroid homeostasis, neuroactive steroid deficiency (notably allopregnanolone, ALLO), and gut–brain axis alterations. Objective: This study aimed to investigate the effects of finasteride withdrawal (FW) in a rat model and evaluate the potential protective effects of ALLO on gut and hypothalamic inflammation. Methods: Adult male Sprague Dawley rats were treated with finasteride for 20 days, followed by one month of drug withdrawal. A subgroup received ALLO treatment during the withdrawal. Histological, molecular, and biochemical analyses were performed on the colon and hypothalamus. Gut microbiota-derived metabolites and markers of neuroinflammation and blood–brain barrier (BBB) integrity were also assessed. Results: At FW, rats exhibited significant colonic inflammation, including a 4.3-fold increase in Mφ1 levels (p < 0.001), a 2.31-fold decrease in butyrate concentration (p < 0.01), and elevated hypothalamic GFAP and Iba-1 protein expression (+360%, p < 0.01 and +100%, p < 0.01, respectively). ALLO treatment rescued these parameters in both the colon and hypothalamus but only partially restored mucosal and BBB structural integrity, as well as the NF-κB/PPARγ pathway. Conclusions: This preclinical study shows that FW causes inflammation in both the gut and hypothalamus in rats. ALLO treatment helped reduce several of these effects. These results suggest ALLO could have a protective role and have potential as a treatment for PFS patients. Full article

Neuroactive steroids (NAS) have long been recognized for their hypnotic and anesthetic properties in both clinical and preclinical settings. While sex differences in NAS sensitivity are acknowledged, the underlying mechanisms remain poorly understood. Here, we examined sex-specific responses to an endogenous NAS epipregnanolone (EpiP) in wild-type mice using behavioral assessment of hypnosis (loss of righting reflex, LORR) and in vivo electrophysiological recordings. Specifically, local field potentials (LFPs) were recorded from the central medial thalamus (CMT) and electroencephalogram (EEG) signals were recorded from the barrel cortex. We found that EpiP-induced LORR exhibited clear sex differences, with females showing increased sensitivity. Spectral power analysis and thalamocortical (TC) and corticocortical (CC) phase synchronization further supported enhanced hypnotic susceptibility in female mice. Our findings reveal characteristic sex-dependent effects of EpiP on the synchronized electrical activity in both thalamus and cortex. These results support renewed exploration of endogenous NAS as clinically relevant anesthetic agents. Full article

Postpartum depression (PPD) remains a significant health concern worldwide. Both non-pharmacological and pharmacological treatments are available for patients with PPD; however, the standard approach involving selective serotonin reuptake inhibitors (SSRIs) and other antidepressants fails to provide a rapid response. This narrative review presents basic clinical and epidemiological data on PPD, summarizes currently used pharmacotherapies of PPD, highlights their limitations, and discusses new therapies based on a revised understanding of the disease’s pathogenesis. Numerous studies indicate that dysregulation of GABAergic neurotransmission, which may result from fluctuating levels of neuroactive steroids during pregnancy and the postpartum period, plays an important role in the complex pathology of PPD. Considering this, neuroactive steroids, which act as positive allosteric modulators of central GABA_A receptors (GABA_ARs), may offer new promising avenues for treating PPD. The first rapid-acting neurosteroid approved by the FDA to treat PPD in women is brexanolone, although its use is constrained by pharmacokinetic properties. The first oral neuroactive steroid-based antidepressant approved by the FDA for PPD is zuranolone. This review discusses the molecular mechanism of zuranolone action and the results of preclinical and clinical studies regarding the effectiveness and safety of the drug in treating PPD. Full article

Background/Objectives: Postpartum depression (PPD) affects approximately 10–20% of women during and after pregnancy, posing significant risks to maternal health, infant development, and family dynamics. Identifying modifiable risk factors is essential for prevention. Emerging evidence suggests that vitamin D, a neuroactive steroid hormone involved in neurotransmitter synthesis, neuroinflammation regulation, and calcium homeostasis, may play a protective role against mood disorders, including PPD. Methods: The search was conducted through a comprehensive search of the PubMed, Scopus, and Web of Science databases using a combination of Medical Subject Headings (MeSH) and free-text terms including “vitamin D”, “25-hydroxyvitamin D”, “deficiency”, “pregnancy”, “postpartum”, “depression”, “antenatal depression”, “maternal mental health”, and “perinatal mood disorders”. Results: Numerous observational studies and systematic review reports around the world reinforce the potential global relevance of vitamin D insufficiency. This study advances personalized and precision medicine approaches by emphasizing the importance of individualized screening for vitamin D deficiency during pregnancy and postpartum, enabling tailored interventions that could mitigate the risk of postpartum depression. Conclusions: In conclusion, while a definitive causal relationship between vitamin D deficiency and perinatal depression remains unproven, screening for vitamin D levels during pregnancy could serve as a low-risk intervention to support maternal mental health. Future research should focus on well designed, large-scale randomized trials and standardization of diagnostic criteria to clarify vitamin D’s role in preventing perinatal depression. Recognizing vitamin D status as a modifiable biomarker allows for targeted nutritional and pharmacological strategies to optimize maternal mental health. Full article

Epilepsy is a chronic neurological disorder with significant treatment challenges, necessitating the search for alternative therapies. This study evaluates the anticonvulsant activity and toxicological profile of Verbesina persicifolia leaf extracts. Methanolic and sequential fractions (hexane, dichloromethane, ethyl acetate, and methanol) were tested using a pentylenetetrazole (PTZ)-induced seizure model in zebrafish (Danio rerio), measuring seizure latency, severity, and survival rates. Phytochemical screening confirmed the presence of flavonoids, alkaloids, and steroids, suggesting potential neuroactive properties. The hexane extracts significantly increased seizure latency and survival rates, with co-administration of hexane extract (5 µg/mL) and diazepam (35.5 µM) further enhancing these effects. Toxicity assessment in Artemia salina indicated low to moderate toxicity in methanolic extracts, while sequential fractions exhibited higher toxicity, particularly in hexane and ethyl acetate extracts. These findings suggest that V. persicifolia extracts exert anticonvulsant effects, likely through GABAergic modulation, and exhibit a favorable safety profile at therapeutic doses. The results support further investigations to isolate active constituents, confirm their mechanisms of action, and explore their potential as plant-derived anticonvulsant agents. Full article

Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disease of the central nervous system. The manifestation of MS is related to steroid changes during the menstrual cycle and pregnancy. As data focusing on the effect of anti-MS drug treatment on steroidome are scarce, we evaluated steroidomic changes (79 steroids) in 61 female MS patients of reproductive age 39 (29, 47) years (median with quartiles) after treatment with anti-MS drugs on the GC-MS/MS platform and immunoassays (cortisol and estradiol). The changes were assessed using steroid levels and steroid molar ratios (SMRs) that may reflect the activities of steroidogenic enzymes (SMRs). A repeated measures ANOVA, followed by multiple comparisons and OPLS models, were used for statistical analyses. The anti-MS treatment decreased steroid levels in the follicular phase. Anti-CD20 monoclonal antibodies (mAb), such as ofatumumab and ocrelizumab; inhibitors of the sphingosine-1-phosphate receptor (S1PRI); and IFNβ-1a decreased circulating 17-hydroxy-pregnanes and shifted the CYP17A1 functioning from the hydroxylase- toward the lyase step. Decreased conjugated/unconjugated steroid ratios were found after treatment with anti-MS drugs, especially for glatiramer acetate and anti-CD20 mAb. In the luteal phase, IFN-β1a treatment increased steroidogenesis; both IFN-β1a and ocrelizumab increased AKR1D1, and S1PRI increased SRD5A functioning. Anti-CD20 mAb reduced the functioning of enzymes catalyzing the synthesis of immunomodulatory 7α/β and 16α-hydroxy-androgens, which may affect the severity of MS. The above findings may be important concerning the alterations in bioactive steroids, such as cortisol; active androgens and estrogens; and neuroactive, neuroprotective, and immunomodulatory steroids in terms of optimization of anti-MS treatment. Full article

Progestogens’ anti-anxiety and anti-depressive effects and mechanisms are not well-understood. Progestogens are hypothesized to have anti-anxiety and anti-depressive effects on behavior, independent of actions at nuclear progestin receptors (NPRs) and dependent on allopregnanolone (5α-pregnan-3α-ol-20-one; 3α,5α-THP), a 5α-reduced, neuroactive metabolite of progesterone (P₄). Adult c57 mice in behavioral estrus (proestrus; pro) showed more anti-anxiety-like and anti-depressant-like behavior and higher levels of estradiol (E₂), P₄, and allopregnanolone in the hippocampus/amygdala complex. Proestrus c57 > 5α-reductase knockout (5αRKO) mice made more central entries in an open field than diestrus c57 and 5αRKO mice that were not different. Ovariectomized (OVX) c57 mice administered 1, 2, or 4 mg/kg P₄ SC showed dosage-dependent increases in central entries in an open field (more anti-anxiety-like behavior); 5αRKO mice had maximal increases at 1–2 mg/kg P₄. OVX c57 and 5αRKO mice showed maximum increases in central entries with SC 3α,5α-THP (4 mg/kg), and c57s showed a similar maximal response to P₄ (4 mg/kg), but 5αRKOs response was half at that dosage. P₄ (4 mg/kg SC to OVX c57 or progestin receptor knockout (PRKO) mice decreased immobility (depression-like behavior) in the forced swim task. Effects of E₂ and veh were similar in both groups. Levels of 3α,5α-THP in the hippocampus/amygdala were consistent with effects on central entries in the open field. Levels of brain-derived neurotrophic factor (BDNF) in the hippocampus/amygdala were greater among E₂-primed (0.09 mg/kg, SC) vs vehicle-administered mice. In sum, adult female mice can be responsive to P₄ for anti-anxiety/anti-depressant-like behavior; such effects may be independent of NPRs but require 5α-reduction and E₂’s priming actions at BDNF in the hippocampus/amygdala complex. Full article

Substance use disorders (SUDs), including cocaine use disorder (CUD), have significant negative health risks and impose a substantial social burden, yet effective treatments are limited. Pregnenolone, a neuroactive steroid precursor, has been shown to reduce alcohol craving and normalize stress biology in individuals with CUD, but its clinical utility has been questioned due to limited data on bioavailability and the stability of blood levels in humans. Thus, this pilot study aimed to determine whether twice-daily oral pregnenolone (PREG) at 300 mg/day and 500 mg/day versus placebo in week two of PREG administration led to stable increased plasma pregnenolone levels in individuals with CUD. Seven treatment-seeking individuals with CUD, enrolled in an eight-week double-blind clinical trial, were randomized to receive placebo (n = 2) or pregnenolone at 300 mg/day (n = 3) or 500 mg/day (n = 2). For the first two weeks of the eight-week trial, participants were admitted to an inpatient Clinical Neuroscience Research Unit for repeated serial sampling of plasma pregnenolone concentrations over a 32.5 h period in week two of their inpatient stay while taking their assigned study drug under observation. Pregnenolone levels showed a significant main effect of the medication group (p = 0.039), with sustained higher levels in the 300 mg (p = 0.018) and 500 mg (p = 0.035) groups compared to placebo, and no significant difference between the two pregnenolone dosing groups. Moreover, correlation analyses showed that after observed study medication dosing on repeated sampling day 1, levels of pregnenolone were highly associated across time, with strong, positive correlations between time of dosing and 2 h (r = 0.80, p = 0.031), 4 h (r = 0.80, p = 0.031), 6 h (r = 0.86, p = 0.013), and 8 h post-dosing (r = 0.97, p < 0.001). These findings from this pilot study suggest that chronic twice-daily/“bis in die” (b.i.d.) oral administration of pregnenolone at both 300 mg/day and 500 mg/day achieved stable and reliable elevated plasma pregnenolone levels over 32.5 h in individuals with CUD, thereby supporting the good bioavailability of pregnenolone in these samples. These data indicate that twice-daily chronic dosing may overcome any potential concerns of poor bioavailability and rapid metabolism of pregnenolone in humans, and support further clinical investigations into pregnenolone’s role in the treatment of cocaine use disorders. Full article

The endogenous neurosteroid (3α,5α)-3-hydroxypregnan-20-one (3α,5α-THP) modulates inflammatory and neuroinflammatory signaling through toll-like receptors (TLRs) in human and mouse macrophages, human blood cells and alcohol-preferring (P) rat brains. Although it is recognized that 3α,5α-THP inhibits TLR4 activation by blocking interactions with MD2 and MyD88, the comprehensive molecular mechanisms remain to be elucidated. This study explores additional TLR4 activation sites, including TIRAP binding to MyD88, which is pivotal for MyD88 myddosome formation, as well as LPS interactions with the TLR4:MD2 complex. Both male and female P rats (n = 8/group) received intraperitoneal administration of 3α,5α-THP (15 mg/kg; 30 min) or a vehicle control, and their hippocampi were analyzed using immunoprecipitation and immunoblotting techniques. 3α,5α-THP significantly reduces the levels of inflammatory mediators IL-1β and HMGB1, confirming its anti-inflammatory actions. We found that MyD88 binds to TLR4, IRAK4, IRAK1, and TIRAP. Notably, 3α,5α-THP significantly reduces MyD88-TIRAP binding (Males: −31 ± 9%, t-test, p < 0.005; Females: −53 ± 15%, t-test, p < 0.005), without altering MyD88 interactions with IRAK4 or IRAK1, or the baseline expression of these proteins. Additionally, molecular docking and molecular dynamic analysis revealed 3α,5α-THP binding sites on the TLR4:MD2 complex, targeting a hydrophobic pocket of MD2 usually occupied by Lipid A of LPS. Surface plasmon resonance (SPR) assays validated that 3α,5α-THP disrupts MD2 binding of Lipid A (Kd = 4.36 ± 5.7 μM) with an inhibition constant (Ki) of 4.5 ± 1.65 nM. These findings indicate that 3α,5α-THP inhibition of inflammatory mediator production involves blocking critical protein-lipid and protein-protein interactions at key sites of TLR4 activation, shedding light on its mechanisms of action and underscoring its therapeutic potential against TLR4-driven inflammation. Full article

Epilepsy is characterized by abnormal neuronal firing in the brain. Several therapeutic strategies exist for epilepsy; however, several patients remain poorly treated. Therefore, the development of effective treatments remains a high priority in the field. Neuroactive steroids can potentiate extra-synaptic and synaptic GABA_A receptors, thereby providing therapeutic benefits relative to benzodiazepines. This research study investigated the therapeutic effectiveness and underlying mechanisms of LPM682000012, a new synthetic neuroactive steroid-positive allosteric modulator (PAM) of GABA_A receptors employed for treating epilepsy. Acute and chronic rat epilepsy models were established to identify the anti-seizure potency of LPM682000012. The dose-dependent sedative effects of LPM682000012 and Ganaxolone in normal rats were evaluated, which revealed that they both dose-dependently alleviated acute epileptic seizure in the pentylenetetrazol (PTZ)-mediated seizure model. Furthermore, LPM682000012 indicated an enhanced safety profile than Ganaxolone. Moreover, LPM682000012 also indicated therapeutic effects in the kainic acid (KA)-induced chronic spontaneous seizure model. Morphologically, LPM682000012 decreased neuronal loss in the hippocampal CA1 and CA3 regions and increased dendritic spine density in the CA1 region. In addition, mechanical analyses, including transcriptomics, Western blot, and proteomics analyses, revealed that the Serpina3n/NF-κB signaling pathway was up-regulated in epileptic rat hippocampal tissue, and LPM682000012 treatment reversed these changes. In summary, this report demonstrated that the novel neurosteroid GABA_A PAM LPM682000012 activated the synaptic and extra-synaptic GABA_A receptors and alleviated KA-induced neuronal loss and synaptic remodeling, potentially by down-regulating the Serpina3n/NF-κB signaling pathways. The results provide evidence that LPM682000012 is a potential anti-seizure pharmacotherapy candidate for epilepsy and warrants further research. Full article

5β-Dihydrosteroids are produced by the reduction of Δ⁴-3-ketosteroids catalyzed by steroid 5β-reductase (AKR1D1). By analogy with steroid 5α-reductase, genetic deficiency exists in AKR1D1 which leads to errors in newborn metabolism and in this case to bile acid deficiency. Also, like the 5α-dihydrosteroids (e.g., 5α-dihydrotestosterone), the 5β-dihydrosteroids produced by AKR1D1 are not inactive but regulate ligand access to nuclear receptors, can act as ligands for nuclear and membrane-bound receptors, and regulate ion-channel opening. For example, 5β-reduction of cortisol and cortisone yields the corresponding 5β-dihydroglucocorticoids which are inactive on the glucocorticoid receptor (GR) and provides an additional mechanism of pre-receptor regulation of ligands for the GR in liver cells. By contrast, 5β-pregnanes can act as neuroactive steroids at the GABA_A and NMDA receptors and at low-voltage-activated calcium channels, act as tocolytic agents, have analgesic activity and act as ligands for PXR, while bile acids act as ligands for FXR and thereby control cholesterol homeostasis. The 5β-androstanes also have potent vasodilatory properties and work through blockade of Ca²⁺ channels. Thus, a preference for 5β-dihydrosteroids to work at the membrane level exists via a variety of mechanisms. This article reviews the field and identifies gaps in knowledge to be addressed in future research. Full article

Light is a key environmental factor regulating reproduction in avians. However, the mechanism of light intensity regulating ovarian development is still unclear. In this study, 5-week-old (5 wk) partridge broiler breeders were randomly divided into a low-light-intensity group (LL group) and a natural-light-intensity group (NL group) (n = 100). In the rearing period (5 wk to 22 wk), the light intensity of the LL group and NL group were 0.41 ± 0.05 lux and 45.39 ± 1.09 lux, and in the laying period (23 wk to 32 wk) they were 23.92 ± 0.06 lux and 66.93 ± 0.76 lux, respectively. Samples were collected on 22 wk and 32 wk. The results showed that the LL group had a later age at first egg and a longer laying period than the NL group. Serum P4 and LH levels in the LL group were higher than in the NL group on 22 wk (p < 0.05). On 32 wk, P4, E2, LH and FSH levels in the LL group were lower than in the NL group (p < 0.05). Ovarian transcriptomics and metabolomics identified 128 differentially expressed genes (DEGs) and 467 differential metabolites (DMs) on 22 wk; 155 DEGs and 531 DMs on 32 wk between two groups. An enrichment analysis of these DEGs and DMs identified key signaling pathways, including steroid hormone biosynthesis, neuroactive ligand-receptor interaction. In these pathways, genes such as CYP21A1, SSTR2, and NPY may regulate the synthesis of metabolites, including tryptamine, triglycerides, and phenylalanine. These genes and metabolites may play a dominant role in the light-intensity regulation of ovarian development and laying performance in broiler breeders. Full article