The selenoperoxidase GPx4, discovered in 1982, plays a pivotal role in preventing ferroptosis. In a moonlighting function, GPx4, in its mitochondrial and nuclear forms, also contributes to spermatogenesis. The critical advantage of Selenium vs. Sulfur catalysis is the stability of the oxidized form of the chalcogen in the catalytic cycle. While the mechanisms of catalytic cycle are understood, its regulation remains largely unknown. Existing evidence supports the notion that ferroptosis is activated when GPx4 is inhibited, glutathione (GSH) concentration is lowered, or the labile iron pool is expanded. The outcome is framed in the context of oxygen toxicity playing the physiological function of controlling cell death. GPx4 stands out as the sole peroxidase indispensable to aerobic life. Moreover, a recent study exploring the role of the residue Arg152 in GPx4, linked to a fatal although not embryonically lethal disease, revealed that the wild-type enzyme exhibits surface-sensing and positive cooperativity in the presence of cardiolipin. This adds complexity to the mechanism of physiological function encompassing the interaction with acidic phospholipids in mitochondrial membranes. Ferroptosis is implicated in both physio-pathological conditions, including embryogenesis, cancer suppression, neurodegenerations, inflammatory disorders, metabolic syndrome, heart and kidney diseases. No antioxidant enzymatic system can substitute for GPx4 in inhibiting ferroptosis, emphasizing the vital role of selenium. Phenolic antioxidants, which reduce lipid hydroperoxyl radicals, can only inhibit lipid peroxidation under physiological conditions, and thus ferroptosis, when the lipid hydroperoxides formed are immediately reduced by GPx4. In contrast, the ferroptosis inhibitor Ferrostatin-1 (Fer-1) proves to be significantly more efficient than phenolic antioxidants. Analytical and computational evidence supports the notion of a pseudo-catalytic cycle where the ferrostatin-iron complex, both produces and reduces lipid alkoxyl radicals from lipid hydroperoxides. This discloses the roadmap for the identification of innovative antioxidants competent for preventing ferroptosis.

Oxysterols are oxidized derivatives of cholesterol initially considered as simple metabolic byproducts, nowadays recognized to play significant roles in various biological and pathological processes. In physiology, they are involved in the regulation of cellular processes beyond cholesterol metabolism, influencing cell proliferation, differentiation, apoptosis, and inflammation through various signaling pathways. In medicine, the study of oxysterols holds promise for understanding and treating various diseases, particularly those associated with dysregulated cholesterol metabolism and inflammation. Indeed, some oxysterols have been associated with adverse health effects, including cytotoxicity, pro-inflammatory effects, and potential contributions to the development of chronic diseases. Dysfunctions in oxysterol metabolism have been implicated in the pathogenesis of cardiovascular diseases, neurodegenerative disorders, and certain cancers. Targeting oxysterol pathways could therefore offer novel therapeutic strategies for these conditions. Oxysterols have potential applications in the pharmaceutical and biotechnology industries. Those generated by cholesterol autoxidation can be used as biomarkers for assessing oxidative stress conditions. Additionally, defined oxysterols of enzymatic origin and/or synthetic oxysterol analogs might be developed as antiviral agents. Oxysterols generated through autoxidation processes can serve as markers of lipid oxidation in cholesterol-containing foods and their quantification can help assess the quality and shelf life of food products, and also for ensuring food safety and consumer health. Finally, with regard to skin health and cosmetics industry, prolonged or excessive exposure to and/or formation of certain toxic oxysterols could potentially damage skin cells and disrupt skin barrier function. Therefore, careful formulation and dosage control are essential to ensure the safety of skincare products. Overall, the study of oxysterols spans molecular biology, medicine, and industry, with implications for understanding fundamental biological processes, developing new medical, industrial, and advancing biotechnological applications.

In recent decades, a global increase in the incidence of skin cancer, particularly squamous cell carcinoma (SCC), has been observed. To explore the pathogenesis and potential therapeutic approaches for this cancer type, in vivo studies employing various mouse models and ultraviolet (UV) light have been conducted. A comparative study on skin carcinogenesis across four hairless mouse models subjected to UV light exposure was initiated. The mouse strains utilized in this research were: SKH-hr1, SKH-hr2, SKH-hr2+ApoE, and immunodeficient Nude. Based on the various measured parameters, in contrast to the SKH-hr1, SKH-hr2+apoE and SKH-hr2 models were identified as the most appropriate.  The bark extract of Pinus maritima (PBE) was examined for SCC preventive action. It was evaluated in two different experimental animal tumor models induced by ultraviolet radiation (UVR) and combination of UVR with 7,12-dimethylbenz[a]anthracene. A significant decrease in the number of animals bearing tumors, increase in viability and delayed appearance of tumors were observed. Through immunochemical analysis, the expression of P-glycoprotein, multi-drug resistance-associated protein (MRP), and glucose (GLUT-1) transporters in SCC, SCC adjacent area, and normal skin tissues were examined. It was revealed that all assessed transporters were expressed across all skin tissues; however, expression levels were notably higher in tumor and tumor-adjacent areas compared to normal tissues. Male and female hairless SKH-2 mice were exposed for 10 months to cigarette smoke (CS) and/or UV light after administration or not of French maritime pine bark extract (PBE) to study the SCC induction and possible protection by PBE. The results showed that UV and CS were harmful and act synergistically inducing SCC, whereas PBE seems to protect skin against SCC. Type 1 and 2 diabetic, and nondiabetic male mice were exposed to UV radiation for eight months. Remarkably, Type 1 diabetic mice did not develop squamous cell carcinoma or pigmented nevi, contrary to normal and Type 2 diabetic skin. Type 1 diabetic mice showed protection against oxidative stress.

Ageing is a complex process characterised by the gradual deterioration of physiological functions and increased susceptibility to various age-related diseases. Mitochondrial dysfunction is an important factor contributing to ageing. Sirtuin 3 (Sirt3), a mitochondrial protein essential for energy homeostasis, plays a critical role in maintaining mitochondrial function, as loss of Sirt3 reduces energy and impairs cellular repair, which accelerates ageing. The aim of this study was to investigate the role of Sirt3 in male and female mouse embryonic fibroblasts (MEF) exposed to etoposide-induced DNA damage. We employed state-of-the-art genetic, molecular, and imaging technologies as well as metabolomic analyses to provide insights into the molecular mechanisms underlying these responses. We found that the loss of Sirt3 affected metabolic responses differently depending on sex: while male MEF showed minimal damage, possibly due to earlier stress adaptation, female MEF lacking Sirt3 were more vulnerable, suggesting that Sirt3 plays a critical role in enhancing their ability to withstand such challenges. By focusing on Sirt3 and sex-specific signalling pathways it modulates, this study has a potential for developing new strategies to combat diseases associated with DNA damage — a cornerstone of the ageing process.

Individual complexes of the mitochondrial oxidative phosphorylation system (OXPHOS) are not linked solely by their function; they also share dependencies at the maintenance/assembly level, where one complex depends on the presence of a different individual complex. Despite the relevance of this ‘interdependence’ behavior for mitochondrial diseases, its true nature remains elusive. To understand the mechanism that can explain this phenomenon, we examined the consequences of the aberration of different OXPHOS complexes in human cells. We demonstrate here that complete disruption of each of the OXPHOS complexes resulted in a perturbation in energy deficiency sensing pathways, including the integrated stress response (ISR) pathway. The secondary decrease of complex I (cI) level was triggered by both complex IV and complex V deficiency, and it was independent of ISR signaling. On the other hand, we identified the unifying mechanism behind cI downregulation in the downregulation of mitochondrial ribosomal proteins and, thus, mitochondrial translation. We conclude that the secondary cI defect is due to mitochondrial protein synthesis attenuation, while the responsible signaling pathways could differ based on the origin of the OXPHOS defect.

Ionising radiation damages DNA directly, or indirectly, causing water radiolysis and formation of free radicals. Indirect irradiation effects could be diminished in the presence of free radical scavengers, such as dimethyl sulfoxide (DMSO). Such conditions would allow the evaluation of direct radiation effects and provide a better understanding of cellular response to irradiation-induced damages. The goal of this study was to investigate the effects of low (γ-rays) and high linear energy transfer (LET) radiation (carbon ions) in non-small lung cancer cells HTB177. Cells were pre-treated with DMSO and irradiated with 60Co γ-rays and 62 MeV/u carbon ions, with doses ranging from 1-5 Gy. Results obtained by clonogenic survival and γ-H2AX foci assay showed that DMSO increased cell survival and decreased number of DNA damages, which points to radioprotective effect of DMSO. The contribution of direct and indirect radiation effects was estimated by the degree of protection (DP) in presence of DMSO. The values of DP rose in a concentration-dependent manner in all irradiated samples. In cells irradiated with γ-rays, 35% of damages were caused directly, while 65% of lesions could be attributed to indirect radiation actions. In presence of carbon ions, contribution of direct effects was 49%, while 51% of damage resulted from indirect radiation effects, showing that free radicals attain an important role in both low and high LET irradiations. The obtained results showed that DMSO can be used as a free radical scavenger to examine the direct and indirect effects on human cancer cells. The numerical Monte Carlo simulations allow modelling of direct and indirect irradiation actions in cancer cells with photons and hadrons. Therefore, this data will be used for validation and further improvement of numerical simulations in comparison to the data collected on different cell lines and irradiation energies, with the goal to improve therapeutic protocols.

Mechanisms and factors that lead to the formation of lipomas, benign tumors of adipose tissue, are still insufficiently elucidated. Mesenchymal stem cells (MSCs) isolated from lipomas have some similar characteristics to MSCs isolated from white adipose tissue but differ at the molecular level and in their differentiation potential. Considering histological appearance of lipomas, it is not clear to what extent lipomas share common characteristics with other adipose tissue type, brown adipose tissue. Therefore, the aim of this study was to examine the level of uncoupling protein 1 (UCP1), a marker of brown adipose tissue, expression in lipoma tissue as well as in MSCs isolated from lipomas, i.e. lipoma-derived mesenchymal stem cells (LDSCs). LDSCs were grown in standard cell culture conditions and subjected to adipogenic differentiation. UCP1 expression was examined at the RNA level, using Real-Time PCR, and at the protein level, using immunohistochemistry and immunogold staining. Expression of UCP1 in lipoma tissue and LDSCs was compared with the expression of UCP1 in subcutaneous white adipose tissue (scWAT) and adipose-derived mesenchymal stem cells (ADSCs) grown and differentiated in the same cell culture conditions. Differences were observed in UCP1 expression at both RNA and protein levels in lipomas compared to scWAT directing the future research towards the potential of browning mechanisms of adipose tissue involved in lipoma tissue formation.

This research was financially supported by the Science Fund of the Republic of Serbia, PROMIS, #6066747, WARMED and the Ministry of Science, Technological Development and Innovations of the Republic of Serbia, Contract No. 451-03-65/2024-03/200113.

The metastasis of breast cancer to the axillary lymph nodes represents a crucial aspect of disease progression and prognostic evaluation. The presence of metastases in the axillary lymph nodes is a key indicator that breast cancer is in an advanced stage, which can influence the therapeutic approach and the patient's prognosis. For this reason, we conducted a study aimed at examining the factors that contribute to the presence of metastases in lymph nodes in our female population. This research represents a prospective study conducted at the Institute of Oncology of Vojvodina in Sremska Kamenica. The study included 72 female participants diagnosed with breast cancer who underwent surgery at the Institute of Oncology of Vojvodina and had not received preoperative chemotherapy or radiation therapy. Initially, anamnestic data were collected from the participants, followed by a pathohistological analysis of the tumor tissue samples, including immunohistochemical analysis. We examined the influence of age, tumor size, activity of estrogen, progesterone, and HER2 receptors (human epidermal growth factor receptor-2)  in tumors, as well as the occurrence of menarche and breastfeeding duration, on the presence of metastases in axillary lymph nodes. The results of binary logistic regression showed that the only significant predictor for the presence of metastases in axillary lymph nodes was tumor size (p=0.01, Wald=6.57, and Exp(B)=1.11), while the other examined predictors were not statistically significant (p>0.05). In our study population, the size of the breast cancer was crucial for the presence of metastases in the axillary lymph nodes.

This research was supported by the Science Fund of the Republic of Serbia, #7750238, Exploring new avenues in breast cancer research: Redox and metabolic reprogramming of cancer and associated adipose tissue - REFRAME.

Amphibians are the most threatened vertebrate class. Exposure to pesticides and climate change are considered pivotal factors in the global decline of their populations. Glyphosate-based formulations are the most widely used herbicides, but increasing evidence of their harmful effects, including oxidative stress in exposed organisms, has sparked a heated debate. Current climate prediction models assume a global temperature rise of 3 °C to 5 °C in the coming decades. In poikilotherms, any changes in ambient temperature are directly translated into changes in physiological and biochemical processes. Furthermore, elevated temperatures could intensify the toxic effects of pesticides present in the environment. The aim of this study was to examine the effects of low, environmentally realistic concentrations of glyphosate-based herbicides (30 µg/L active ingredient) and elevated temperature (optimal t1=19°C and increased t2=23°C) on glutathione content (GSH), antioxidant enzyme activities (SOD, CAT, GSH-Px, GR and GST), activity of acetylcholinesterase (AChE) and levels of oxidative damage (TBARS - lipid peroxidation and PC - protein carbonylation) in larvae of the Balkan crested newt (T. ivanbureschi). Our findings revealed that glyphosate had a significant effect on the activity of all antioxidative enzymes, with the exception of SOD. Herbicide and elevated temperature led to a significant increase in the activities of CAT, GSH-Px, GST, and GR, as well as GSH concentration. This response of the antioxidative defense system prevented oxidative damage to lipids and proteins. Glyphosate exhibited a neurotoxic effect by inhibiting AChE only at elevated temperatures, while no significant change occurred at the optimal temperature. The findings suggest the importance of examining the potentially harmful effects of glyphosate in different ecological contexts, such as an increase in average temperatures by several degrees predicted by future climate scenarios.

Human activity and rapid urbanization created disturbance factors that drastically changed natural habitats. The introduction of artificial light at night changed natural light-dark regimes affecting a range of biological processes. Disruption of circadian rhythm is linked with changes in endocrine and neurobiological systems that control hormonal regulation, food intake, metabolism, reproduction, and behavior of animals. Oxidative stress was suggested as a possible mechanism through which artificial light could affect an organism’s physiology and health. We examined the oxidative status of tree frog (Hyla arborea) under two artificial night light intensities 20 lux and 90 lux. Artificial light affects the antioxidant system of both larval and juvenile stages. Larvae had higher activity for glutathione peroxidase only for 90 lux, while greater lipid damage was observed in individuals under both light regimes compared to control. Juvenile individuals showed boosted antioxidant response seen through higher activities of superoxide dismutase, catalase, and glutathione peroxidase. Finally, development under artificial light led to higher levels of protein damage in juveniles. Artificial light at night acts primarily through direct effects and can persist across life stages. Overall results point out that exposure to artificial light alters physiological traits in amphibians, such as oxidative status that could have various consequences on individuals in natural populations.