γ‐Oryzanol (ORY) is well known for its antioxidant potential. However, the mechanism by which ORY exerts its antioxidant effect is still unclear. In this paper, the antioxidant properties of ORY were investigated for its potential effects as a reactive oxygen and nitrogen species (ROS/RNS) scavenger and in activating antioxidant‐promoting intracellular pathways utilizing the human embryonic kidney cells (HEK‐293). The 24 h ORY exposure significantly prevented hydrogen peroxide‐ (H₂O₂‐) induced ROS/RNS production at 3 h, and this effect was sustained for at least 24 h. ORY pretreatment also enhanced the activity of antioxidant enzymes: superoxide dismutase (SOD) and glutathione peroxidase (GPX). Interestingly, ORY induced the nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2) nuclear translocation and upregulation of Nrf2‐dependent defensive genes such as NAD(P)H quinone reductase (NQO1), heme oxygenase‐1 (HO‐1), and glutathione synthetase (GSS) at mRNA and protein levels in both basal condition and after H₂O₂ insult. Thus, this study suggested an intriguing effect of ORY in modulating the Nrf2 pathway, which is also involved in regulating longevity as well as age‐related diseases.

Adult neurotoxicity (ANT) and developmental neurotoxicity (DNT) assessments aim to understand the adverse effects and underlying mechanisms of toxicants on the human nervous system. In recent years, there has been an increasing focus on the so-called new approach methodologies (NAMs). The Organization for Economic Co-operation and Development (OECD), together with European and American regulatory agencies, promote the use of validated alternative test systems, but to date, guidelines for regulatory DNT and ANT assessment rely primarily on classical animal testing. Alternative methods include both non-animal approaches and test systems on non-vertebrates (e.g., nematodes) or non-mammals (e.g., fish). Therefore, this review summarizes the recent advances of NAMs focusing on ANT and DNT and highlights the potential and current critical issues for the full implementation of these methods in the future. The status of the DNT in vitro battery (DNT IVB) is also reviewed as a first step of NAMs for the assessment of neurotoxicity in the regulatory context. Critical issues such as (i) the need for test batteries and method integration (from in silico and in vitro to in vivo alternatives, e.g., zebrafish, C. elegans) requiring interdisciplinarity to manage complexity, (ii) interlaboratory transferability, and (iii) the urgent need for method validation are discussed.

An adequate protection from oxidative and inflammatory reactions, together with the promotion of oligodendrocyte progenitor (OP) differentiation, is needed to recover from myelin damage in demyelinating diseases. Mitochondria are targets of inflammatory and oxidative insults and are essential in oligodendrocyte differentiation. It is known that nuclear factor-erythroid 2-related factor/antioxidant responsive element (NRF2/ARE) and peroxisome proliferator-activated receptor gamma/PPAR-γ response element (PPAR-γ/PPRE) pathways control inflammation and overcome mitochondrial impairment. In this study, we analyzed the effects of activators of these pathways on mitochondrial features, protection from inflammatory/mitochondrial insults and cell differentiation in OP cultures, to depict the specificities and similarities of their actions. We used dimethyl-fumarate (DMF) and pioglitazone (pio) as agents activating NRF2 and PPAR-γ, respectively, and two synthetic hybrids acting differently on the NRF2/ARE pathway. Only DMF and compound 1 caused early effects on the mitochondria. Both DMF and pio induced mitochondrial biogenesis but different antioxidant repertoires. Moreover, pio induced OP differentiation more efficiently than DMF. Finally, DMF, pio and compound 1 protected from tumor necrosis factor-alpha (TNF-α) insult, with pio showing faster kinetics of action and compound 1 a higher activity than DMF. In conclusion, NRF2 and PPAR-γ by inducing partially overlapping pathways accomplish complementary functions aimed at the preservation of mitochondrial function, the defense against oxidative stress and the promotion of OP differentiation.

Background and Purpose: Dehydroepiandrosterone (DHEA) is thought to be an anti‐glucocorticoid hormone known to be fully functional in young people but deficient in aged humans. Our previous data suggest that DHEA not only counteracts the effect of cortisol on RACK1 expression, a protein required both for the correct functioning of immune cells and for PKC‐dependent pathway activation, but also modulates the inhibitory effect of cortisol on LPS‐induced cytokine production. The purpose of this study was to investigate the effect of DHEA on the splicing mechanism of the human glucocorticoid receptor (GR).Experimental Approach: The THP1 monocytic cell line was used as a cellular model. Cytokine production was measured by specific elisa. Western blot and real‐time RT‐PCR were used, where appropriate, to determine the effect of DHEA on GRs, serine/arginine‐rich proteins (SRp), and RACK1 protein and mRNA. Small‐interfering RNA was used to down‐regulate GRβ.Key Results: DHEA induced a dose‐related up‐regulation of GRβ and GRβ knockdown completely prevented DHEA‐induced RACK1 expression and modulation of cytokine release. Moreover, we showed that DHEA influenced the expression of some components of the SRps found within the spliceosome, the main regulators of the alternative splicing of the GR gene.Conclusions and Implications: These data contribute to our understanding of the mechanism of action of DHEA and its effect on the immune system and as an anti‐glucocorticoid agent.