Ebselen alters cellular oxidative status and induces endoplasmic reticulum stress in rat hippocampal astrocytes

Exploring the impact of environmental factors on male reproductive health through epigenetics

Male infertility has become an increasingly severe global health issue, with its incidence significantly rising over the past few decades. This paper delves into the crucial role of epigenetics in male reproductive health, focusing particularly on the effects of DNA methylation, histone modifications, chromatin remodeling and non-coding RNAs regulation on spermatogenesis. Exposure to various environmental factors can cause sperm DNA damage, leading to epigenetic abnormalities. Among these factors, we have discussed heavy metals (including Zinc, Cadmium, Arsenic, Copper), phthalates, electromagnetic radiation, and temperature in detail. Notably, aberrations in DNA methylation are closely associated with various symptoms of male infertility, and histone modifications and chromatin remodeling are essential for sperm maturation and function. By synthesizing existing literature and experimental data, this narrative review investigates how environmental factors influence male reproductive health through epigenetic mechanisms, thus providing new theoretical foundations and practical guidelines for the early diagnosis and treatment of male infertility.

Sorafenib combined with STAT3 knockdown triggers ER stress-induced HCC apoptosis and cGAS-STING-mediated anti-tumor immunity

Sorafenib is the first-line treatment for advanced hepatocellular carcinoma (HCC). However, it is difficult to alleviate this disease process using single-agent chemotherapy. Using combination therapies for advanced HCC has become a major trend. Given that STAT3 overexpression is involved in chemotherapy resistance and the immune escape of HCC cells, it has become a potential therapeutic target for HCC in recent years. GEO database analysis showed that STAT3 levels in tumor tissues from non-responders were significantly higher than those in responders to sorafenib. Our studies demonstrated that STAT3 knockdown promoted sorafenib-induced ER stress-induced apoptosis. Importantly, the DNA released by dead HCC cells stimulated the cGAS-STING signaling pathway in CD103⁺ DCs and promoted type I interferon production, thus, enhancing the anti-tumor function of CD8⁺ T and NK cells. In conclusion, our results revealed that the combination strategy of sorafenib and STAT3 knockdown might be a potential treatment strategy for HCC, directly and efficiently disturbing the tumor features of HCC cells while improving the tumor microenvironment via the cGAS-STING-Type I IFNs axis of DCs, inducing anti-HCC immune responses.

Melatonin relieves heat-induced spermatocyte apoptosis in mouse testes by inhibition of ATF6 and PERK signaling pathways

Normal spermatogenic processes require the scrotal temperature to be lower than that of the body as excessive heat affects spermatogenesis in the testes, reduces sperm quality and quantity, and even causes infertility. Endoplasmic reticulum stress (ERS) is a crucial factor in many pathologies. Although several studies have linked ERS to heat stress, researchers have not yet determined which ERS signaling pathways contribute to heat-induced testicular damage. Melatonin activates antioxidant enzymes, scavenges free radicals, and protects the testes from inflammation; however, few studies have reported on the influence of melatonin on heat-induced testicular damage. Using a murine model of testicular hyperthermia, we observed that heat stress causes both ERS and apoptosis in the testes, especially in the spermatocytes. These observations were confirmed using the mouse spermatocyte cell line GC2, where the Atf6 and Perk signaling pathways were activated during heat stress. Knockout of the above genes effectively reduced spermatocyte damage caused by heat stress. Pretreatment with melatonin alleviated heat-induced apoptosis by inhibiting the Atf6 and Perk signaling pathways. This mitigation was dependent on the melatonin receptors. In vivo experiments verified that melatonin treatment relieved heat-induced testicular damage. In conclusion, our results demonstrated that ATF6 and PERK are important mediators for heat-induced apoptosis, which can be prevented by melatonin treatment. Thus, our study highlights melatonin as a potential therapeutic agent in mammals for subfertility/infertility induced by testicular hyperthermia.

Toxicology and pharmacology of synthetic organoselenium compounds: an update

Here, we addressed the pharmacology and toxicology of synthetic organoselenium compounds and some naturally occurring organoselenium amino acids. The use of selenium as a tool in organic synthesis and as a pharmacological agent goes back to the middle of the nineteenth and the beginning of the twentieth centuries. The rediscovery of ebselen and its investigation in clinical trials have motivated the search for new organoselenium molecules with pharmacological properties. Although ebselen and diselenides have some overlapping pharmacological properties, their molecular targets are not identical. However, they have similar anti-inflammatory and antioxidant activities, possibly, via activation of transcription factors, regulating the expression of antioxidant genes. In short, our knowledge about the pharmacological properties of simple organoselenium compounds is still elusive. However, contrary to our early expectations that they could imitate selenoproteins, organoselenium compounds seem to have non-specific modulatory activation of antioxidant pathways and specific inhibitory effects in some thiol-containing proteins. The thiol-oxidizing properties of organoselenium compounds are considered the molecular basis of their chronic toxicity; however, the acute use of organoselenium compounds as inhibitors of specific thiol-containing enzymes can be of therapeutic significance. In summary, the outcomes of the clinical trials of ebselen as a mimetic of lithium or as an inhibitor of SARS-CoV-2 proteases will be important to the field of organoselenium synthesis. The development of computational techniques that could predict rational modifications in the structure of organoselenium compounds to increase their specificity is required to construct a library of thiol-modifying agents with selectivity toward specific target proteins.

Mechanisms of ebselen as a therapeutic and its pharmacology applications

Ebselen is a synthetic organoselenium radical scavenger compound that possesses glutathione peroxidase-like activity and its own unique bioactivity by reacting with thiols, hydroperoxides and peroxynitrites. Owing to its high affinity toward several essential reactions, ebselen protects cellular components from oxidative and free radical damage, and it has been employed as a useful tool for studying redox-related mechanisms. Based on numerous in vitro and in vivo research, mechanisms are proposed to understand the biomedical and molecular actions of ebselen in health and disease, and it is currently under clinical trials for the prevention and treatment of various human disorders. Based on these outstanding discoveries, this review summarizes the current understanding of the biochemical and molecular characteristics, pharmacological applications and future directions of ebselen.

The other view: the trace element selenium as a micronutrient in thyroid disease, diabetes, and beyond

Antibiotics are provided for infections caused by bacteria, and statins help to control hypercholesterolemia. When hungry, you need to eat, and when you are deficient in a particular nutrient, the diet should be chosen wisely to provide what is missing. In the matter of providing the essential trace element selenium (Se), there are two different but partly overlapping views on its nature and requirements. Some consider it a medication that should be given to a subset of more or less well-defined (thyroid) patients only, in order to alleviate symptoms, to improve the course of the disease or even to provide a cure, alone or in an adjuvant mode. Such treatment attempts are conducted for a short time period, and potential medical benefits and side effects are evaluated thoroughly. One could also approach Se in medicine in a more holistic way and evaluate primarily the nutritional status of the patient before considering supplementation. The available evidence for positive health effects of supplemental Se can be interpreted as the consequence of correcting deficiency instead of speculating on a direct pharmaceutical action. This short review provides a novel view on Se in (thyroid) disease and beyond and offers an alternative explanation for its positive health effects, i.e., its provision of the substrate needed for allowing adequate endogenous expression of those selenoproteins that are required in certain conditions. In Se deficiency, the lack of the trace element constitutes the main limitation for the required adaptation of selenoprotein expression to counteract health risks and alleviate disease symptoms. Supplemental Se lifts this restriction and enables the full endogenous response of selenoprotein expression. However, since Se does not act as a pharmacological medication per se, it should not be viewed as a dangerous drug, and, importantly, current data show that supplemental Se does not cause diabetes.

"Adjusting internal organs and dredging channel" electroacupuncture treatment prevents the development of diabetic peripheral neuropathy by downregulating glucose-related protein 78 (GRP78) and caspase-12 in streptozotocin-diabetic rats

BACKGROUND

The clinical efficacy of electroacupuncture in treating diabetic peripheral neuropathy (DPN) is significant, but the underlying mechanism of action is not clear. Considering that glucose-regulated protein 78 (GRP78) and caspase-12 are major proteins participating in cell apoptosis, we investigated the effects of "adjusting internal organs and dredging channel" electroacupuncture therapy on GRP78 and caspase-12 levels in streptozotocin (STZ)-diabetic rats to elucidate the mechanism of action.

METHODS

Rats were first divided into two groups: one group was rendered diabetic with a single injection of 50 mg/kg STZ, whereas the other normal control group was injected with an equivalent volume of citrate buffer. The STZ-diabetic rats were randomly divided into three groups: model control and electroacupuncture- and mecobalamin-treated groups. After 12 weeks treatment, the therapeutic efficacy of electroacupuncture was assessed using sciatic nerves isolated from rats. In the electroacupuncture group, rats were treated by electroacupuncture for 20 minutes once daily for 6 days each week, with 1 day off, for 12 consecutive weeks. The selected acupressure points include bilateral acupressure points of BL13 (Fehu), BL20 (Pishu), BL23 (Shenshu), LI4 (Hegu), LR3 (faichong), ST36 (Zusanli), and SP6 (Sanyiniiao). Acupressure points were stimulated using a HuaTuo SDZ-V Electric Acupuncture Therapy Apparatus. The acupressure points of BL13 and BL23, as well as SP6 and LR3, were connected on the same side with a dilatational wave of 3 Hz (frequency ratio of 1 : 5) to stimulate the parts of the body to the extent that could be tolerated by the rat. As for the mecobalamin-treated groups, mecobalamin was administrated to rats intragastrically at a dose of 20 mg/kg once daily for 12 consecutive weeks. Immunofluorescence and western blot analysis were used to determine GRP78 and caspase-12 levels in sciatic nerves. In addition, cell apoptosis in sciatic nerves was determined using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling (TUNEL) assay.

RESULTS

Electroacupuncture markedly reduced the pathological injury to sciatic nerves in STZ-diabetic rats. Moreover, electroacupuncture significantly downregulated GRP78 and caspase-12 and reduced cell apoptosis of sciatic nerves in DPN rats.

CONCLUSIONS

Electroacupuncture improved DPN by downregulating GRP78 and caspase-12 and reducing cell apoptosis of sciatic nerves in STZ-diabetic rats, and further inhibited the occurrence of endoplasmic reticulum stress, thus preventing sciatic nerve injuries.

Putative neuroprotective pharmacotherapies to target the staged progression of mental illness

AIM

Neuropsychiatric disorders including depression, bipolar and schizophrenia frequently exhibit a neuroprogressive course from prodrome to chronicity. There are a range of agents exhibiting capacity to attenuate biological mechanisms associated with neuroprogression. This review will update the evidence for putative neuroprotective agents including clinical efficacy, mechanisms of action and limitations in current assessment tools, and identify novel agents with neuroprotective potential.

METHOD

Data for this review were sourced from online databases PUBMED, Embase and Web of Science. Only data published since 2012 were included in this review, no data were excluded based on language or publication origin.

RESULTS

Each of the agents reviewed inhibit one or multiple pathways of neuroprogression including: inflammatory gene expression and cytokine release, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophin dysregulation and apoptotic signalling. Some demonstrate clinical efficacy in preventing neural damage or loss, relapse or cognitive/functional decline. Agents include: the psychotropic medications lithium, second generation antipsychotics and antidepressants; other pharmacological agents such as minocycline, aspirin, cyclooxygenase-2 inhibitors, statins, ketamine and alpha-2-delta ligands; and others such as erythropoietin, oestrogen, leptin, N-acetylcysteine, curcumin, melatonin and ebselen.

CONCLUSIONS

Signals of evidence of clinical neuroprotection are evident for a number of candidate agents. Adjunctive use of multiple agents may present a viable avenue to clinical realization of neuroprotection. Definitive prospective studies of neuroprotection with multimodal assessment tools are required.

Ebselen rescues oxidative-stress-suppressed osteogenic differentiation of bone-marrow-derived mesenchymal stem cells via an antioxidant effect and the PI3K/Akt pathway

BACKGROUND

Patients with metabolic bone diseases often have high risk of titanium implant failure due to compromised bone regeneration ability. Clinical evidence indicates that the poor osteogenic ability is partly because of excessive oxidative stress. To date, specific treatments for these patients are urgently needed. Ebselen, a non-toxic organoselenium compound, is reported to be a potent antioxidant agent. In this study, we hypothesized that ebselen exerted protective effects on osteogenic differentiation of bone-marrow-derived mesenchymal stem cells (BMSCs) under oxidative stress.

METHODS

BMSCs were isolated from SD rats, and their morphology and multiple differentiation abilities were characterized. Proliferation rates of BMSCs treated with different concentrations of ebselen were analyzed. Then BMSCs were pretreated by hydrogen peroxide (H₂O₂), after which ebselen at different concentrations (0, 1, 5, 10 μM) was added, alkaline phosphatase (ALP) activity, mineralization and osteogenic-related protein levels were evaluated and an optimum concentration of ebselen was selected. Subsequently, intracellular reactive oxygen species (ROS) generation and the role of the PI3K/AKT pathway were also investigated.

RESULTS

Ebselen within a proper range could promote the proliferation of BMSCs. H₂O₂-induced oxidative stress suppressed osteogenic differentiation of BMSCs, which was verified by the decrease in ALP activity, calcium deposition, Runx2 and β-catenin expression. However, ebselen could alleviate osteogenic dysfunction of BMSCs. We also observed that ebselen reduced ROS accumulation in H₂O₂-pretreated BMSCs. Moreover, the pro-osteogenic effects afforded by ebselen were almost abolished by the Akt inhibitor.

CONCLUSION

We concluded that ebselen could attenuate osteogenic dysfunction of BMSCs induced by H₂O₂ through an antioxidant effect and the activation of the PI3K/Akt pathway, suggesting that ebselen has a potential therapeutic effect for patients with metabolic bone diseases.

Use of ebselen as a neuroprotective agent in rat spinal cord subjected to traumatic injury

Spinal cord injury (SCI) causes disturbances of motor skills. Free radicals have been shown to be essential for the development of spinal cord trauma. Despite some progress, until now no effective pharmacological therapies against SCI have been verified. The purpose of our experiment was to investigate the neuroprotective effects of ebselen on experimental SCI. Twenty-two rats subjected to SCI were randomly subjected to SCI with no further treatment (n = 10) or intragastric administration of ebselen (10 mg/kg) immediately and 24 hours after SCI. Behavioral changes were assessed using the Basso, Beattie, and Bresnahan locomotor scale and footprint test during 12 weeks after SCI. Histopathological and immunohistochemical analyses of spinal cords and brains were performed at 12 weeks after SCI. Magnetic resonance imaging analysis of spinal cords was also performed at 12 weeks after SCI. Rats treated with ebselen presented only limited neurobehavioral progress as well as reduced spinal cord injuries compared with the control group, namely length of lesions (cysts/scars) visualized histopathologically in the spinal cord sections was less but cavity area was very similar. The same pattern was found in T2-weighted magnetic resonance images (cavities) and diffusion-weighted images (scars). The number of FluoroGold retrogradely labeled neurons in brain stem and motor cortex was several-fold higher in ebselen-treated rats than in the control group. The findings suggest that ebselen has only limited neuroprotective effects on injured spinal cord. All exprimental procedures were approved by the Local Animal Ethics Committee for Experiments on Animals in Katowice (Katowice, Poland) (approval No. 19/2009).

Screening a Repurposing Library for Inhibitors of Multidrug-Resistant Candida auris Identifies Ebselen as a Repositionable Candidate for Antifungal Drug Development

Since its original isolation in 2009, Candida auris has spread across the globe as a causative agent of invasive candidiasis. C. auris is typically intrinsically resistant to fluconazole and can also be resistant to echinocandins and even amphotericin B. Thus, there is an urgent need to find new treatment options against this emerging pathogen. To address this growing problem, we performed a screen of the Prestwick Chemical library, a repurposing library of 1,280 small molecules, consisting mostly of approved off-patent drugs, in search of those with activity against a multidrug-resistant C. auris isolate. Our initial screen, using standardized susceptibility testing methodologies, identified nine miscellaneous compounds with no previous clinical indication as antifungals or antiseptics that displayed activity against C. auris Confirmation and follow-up studies identified ebselen as the drug displaying the most potent activity, with 100% inhibition of growth detected at concentrations as low as 2.5 μM. We further evaluated the ability of ebselen to inhibit C. auris biofilm formation and examined the effects of combination therapies of ebselen with clinically used antifungals. We extended our studies to different C. auris strains with various susceptibility patterns and also confirmed its antifungal activity against Candida albicans and clinical isolates of multiple other Candida species. Furthermore, ebselen displayed a broad spectrum of antifungal actions on the basis of its activity against a variety of medically important fungi, including yeasts and molds. Overall, our results indicate the promise of ebselen as a repositionable agent for the treatment of candidiasis and possibly other mycoses and, in particular, for the treatment of infections refractory to conventional treatment with current antifungals.

Ebselen protects mitochondrial function and oxidative stress while inhibiting the mitochondrial apoptosis pathway after acute spinal cord injury

Ebselen is a fat-soluble small molecule and organic selenium compound that regulates the activity of glutathione peroxidase to alleviate mitochondrial oxidative stress and improve mitochondrial function. In the present study, we aimed to investigate the effects of ebselen on mitochondrial oxidative stress response, mitochondrial apotosis, and motor behaviors after spinal cord injury (SCI). We found that ebselen significantly increased the BBB score in motor behavior, thus suggesting a rescue effect of ebselen on motor function after SCI in rats. Meanwhile, we revealed that ebselen can increase glutathione (GSH) content as well as superoxide dismutase (SOD) and catalase (CAT) activities after SCI-this suggests ebselen has an antioxidant effect. Furthermore, the ATP content and Na⁺-K⁺-ATPase activity in mitochondria were increased by ebselen after SCI, while the mitochondrial membrane potential (MMP) was decreased by ebselen. The Cytochrome C and Smac release from mitochondria were reduced by ebselen after SCI, thus indicating improved membrane permeability by ebselen. Moreover, the alterations in caspase-3, Bax and Bcl-2 protein expression, as well as the proportion of cell apoptosis were improved by ebselen treatment, which together suggested that ebselen has an inhibitory effect on mitochondrial apotosis pathways after SCI. Taken together, our results suggest that ebselen can inhibit secondary damage caused by spinal cord injury. Indeed it plays a neuroprotective role in spinal cord injury perhaps by improving mitochondrial function and inhibiting the mitochondrial apoptosis pathway.

Ebselen impairs cellular oxidative state and induces endoplasmic reticulum stress and activation of crucial mitogen-activated protein kinases in pancreatic tumour AR42J cells

Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) is an organoselenium radical scavenger compound, which has strong antioxidant and anti-inflammatory effects. However, evidence suggests that this compound could exert deleterious actions on cell physiology. In this study, we have analyzed the effect of ebselen on rat pancreatic AR42J cells. Cytosolic free-Ca2+ concentration ([Ca2+ ]c ), cellular oxidative status, setting of endoplasmic reticulum stress, and phosphorylation of major mitogen-activated protein kinases were analyzed. Our results show that ebselen evoked a concentration-dependent increase in [Ca2+ ]c . The compound induced an increase in the generation of reactive oxygen species in the mitochondria. We also observed an increase in global cysteine oxidation in the presence of ebselen. In the presence of ebselen an impairment of cholecystokinin-evoked amylase release was noted. Moreover, involvement of the unfolded protein response markers, ER chaperone and signaling regulator GRP78/BiP, eukaryotic translation initiation factor 2α and X-box binding protein 1 was detected. Finally, increases in the phosphorylation of SAPK/JNK, p38 MAPK, and p44/42 MAPK in the presence of ebselen were also observed. Our results provide evidences for an impairment of cellular oxidative state and enzyme secretion, the induction of endoplasmic reticulum stress and the activation of crucial mitogen-activated protein kinases in the presence of ebselen. As a consequence ebselen exerts a potential toxic effect on AR42J cells.

Lithium Pharmacogenetics: Where Do We Stand?

Preclinical Research Bipolar disorder (BPD) is a chronic and disabling psychiatric disorder with a prevalence of 0.8-1.2% in the general population. Although lithium is considered the first-line treatment, a large percentage of patients do not respond sufficiently. Moreover, lithium can induce severe side effects and has poor tolerance and a narrow therapeutic index. The genetics of lithium response has been largely investigated, but findings have so far failed to identify reliable biomarkers to predict clinical response. This has been largely determined by the highly complex phenotipic and genetic architecture of lithium response. To this regard, collaborative initiatives hold the promise to provide robust and standardized methods to disantenagle this complexity, as well as the capacity to collect large samples of patietnts, a crucial requirement to study the genetics of complex phenotypes. The International Consortium on Lithium Genetics (ConLiGen) has recently published the largest study so far on lithium response reporting significant associations for two long noncoding RNAs (lncRNAs). This result provides relevant insights into the pharmacogenetics of lithium supporting the involvement of the noncoding portion of the genome in modulating clinical response. Although a vast body of research is engaged in dissecting the genetic bases of response to lithium, the several drawbacks of lithium therapy have also stimulated multiple efforts to identify new safer treatments. A drug repurposing approach identified ebselen as a potential lithium mimetic, as it shares with lithium the ability to inhibit inositol monophosphatase. Ebselen, an antioxidant glutathione peroxidase mimetic, represents a valid and promising example of new potential therapeutic interventions for BD, but the paucity of data warrant further investigation to elucidate its potential efficacy and safety in the management of BPD. Nevertheless, findings provided by the growing field of pharmacogenomic research will ultimately lead to the identification of new molecular targets and safer treatments for BPD. Drug Dev Res 77 : 368-373, 2016. © 2016 Wiley Periodicals, Inc.