José Carlos Santos Teixeira

Abstract S-1 MitoPlates™ from Biolog enable the characterization of mitochondria’s function in live cells by measuring the rates of electron flow into and through the electron transport chain from different NADH or FADH2 producing metabolic substrates. This technology uses 96-well microplates pre-coated with triplicate repeats of a set of 31 substrates. Those 31 metabolic substrates have different routes of entry into the mitochondria, use different transporters, and are also oxidated by different dehydrogenases, producing reducing equivalents in the form of NADH or FADH2. The electrons produced upon oxidation of NADH or FADH2 at complex I or II, respectively, then travel to cytochrome c, where a tetrazolium redox dye (MC) can act as terminal acceptor, turning purple and absorbing at 590 nm. This mechanism allows the evaluation of cellular substrate preference by following the kinetics of MC reduction in the presence of selected substrates. In this chapter, we describe the step-by-step protocol to prepare an experiment using MitoPlate S-1 array and the OmniLog instrument to assess the metabolism of human dermal fibroblasts. We also give detailed information on how to analyze the raw data generated by the Biolog Data Analysis software to extract meaningful information and produce useful data visualizations, using reproducible methods based on a single structured dataset. © The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature 2025.

Abstract Mitochondrial dysfunction and increased reactive oxygen species (ROS) generation play an import role in different human pathologies. In this context, mitochondrial targeting of potentially protective antioxidants by their coupling to the lipophilic triphenylphosphonium cation (TPP) is widely applied. Employing a six-carbon (C6) linker, we recently demonstrated that mitochondria-targeted phenolic antioxidants derived from gallic acid (AntiOxBEN2) and caffeic acid (AntiOxCIN4) counterbalance oxidative stress in primary human skin fibroblasts by activating ROS-protective mechanisms. Here we demonstrate that C6-TPP (but not AntiOxBEN2 and AntiOxCIN4) induce cell death in human skin fibroblasts. This indicates that C6-TPP cytoxocity is counterbalanced by the antioxidant moieties of AntiOxBEN2 and AntiOxCIN4. Remarkably, C6-TPP and AntiOxBEN2 (but not AntiOxCIN4) induced a glycolytic switch, as exemplified by a reduced cellular oxygen consumption rate (OCR), increased extracellular acidification rate (ECAR), elevated extracellular lactate levels, and higher protein levels of glucose transporter 1 (GLUT-1). This switch involved activation of AMP-activated protein kinase (AMPK) and fully compensated for the loss in mitochondrial ATP production by sustaining cellular ATP content. When glycolytic switch induction was prevented ( i.e. by using a glucose-free, galactose-containing medium), AntiOxBEN2 induced cell death whereas AntiOxCIN4 did not. We conclude that, despite their similar chemical structure and antioxidant capacity, AntiOxBEN2 and AntiOxCIN4 display both common (redox-adaptive) and specific (bioenergetic-adaptive) effects.

Abstract In the last decades, major changes in ecosystems related to industrial development and environmental modifications have had a direct impact on mammalian fertility, as well as on biodiversity. It is widely demonstrated that all these changes impair reproductive function. Several studies have connected the increase of reactive oxygen species (ROS) generated in mitochondria to the recently identified decline of fertility due to various factors, including heat stress. The study of antioxidants, and especially of mitochondria targeted antioxidants, has been focused on identifying more efficient and less toxic therapies that could circumvent fertility problems. These antioxidants can be derived from natural compounds in the diet and delivered to the mitochondria in more effective forms, providing a much more natural therapy. The use of mitochondriotropic diet-based antioxidants in assisted reproductive technologies (ART) may be an important way to overcome low fertility, allowing the conservation of animal biodiversity and productivity. This paper provides a concise review of the current state of the art on this topic, with a particular focus on the antioxidants mitoquinone, AntiOxBEN2, AntiOxCIN4, urolithin A and piperine, and their effects on bovine and other animal species.

Abstract BackgroundExtracellular matrix (ECM) stiffness is increasingly recognized as a critical regulator of cellular behaviour, governing processes such as proliferation, differentiation, and metabolism. Neurodegenerative diseases are characterized by mitochondrial dysfunction, oxidative stress, impaired autophagy, and progressive softening of the brain tissue, yet research into how mechanical cues influence cellular metabolism in this context remains scarce.Materials and MethodsIn this study, we evaluated the long-term effects of brain-compliant, soft ECM on mitochondrial bioenergetics, redox balance, and autophagic capacity in human neuroblastoma (SH-SY5Y) and mouse hippocampal (HT22) cell lines, as well as primary mouse neurons.ResultsWe observed that prolonged exposure to soft ECM does not impact cell proliferative capacity of neuronal cells but results in mitochondrial bioenergetic dysfunction, redox imbalance, and disrupted autophagic flux. These findings were consistently validated across both human and mouse neuronal cells. Our data indicate a decreased maximal autophagic capacity in cells exposed to long-term soft ECM, potentially due to an imbalance in autophagosome formation and degradation, as demonstrated by decreased LC3 II levels following chloroquine-induced autophagic flux inhibition. This impairment in autophagy was coupled with increased cellular oxidative stress, further indicating metabolic alterations.ConclusionsThese findings emphasize the critical role of ECM stiffness in regulating neuronal cell metabolism and suggest that prolonged exposure to soft ECM may mimic key aspects of neurodegenerative disease pathology, thereby enhancing the physiological relevance of in vitro models. This study underscores the necessity for further research into ECM mechanics as a contributing factor in neurodegenerative disease progression and as a potential target for therapeutic strategies.

Abstract Non-alcoholic fatty liver disease (NAFLD) presents a pervasive global pandemic, affecting approximately 25 % of the world's population. This grave health issue not only demands urgent attention but also stands as a significant economic concern on a global scale. The genesis of NAFLD can be primarily attributed to unhealthy dietary habits and a sedentary lifestyle, albeit certain genetic factors have also been recorded to contribute to its occurrence. NAFLD is characterized by fat accumulation in more than 5 % of hepatocytes according to histological analysis, or >5.6 % of lipid volume fraction in total liver weight in patients. The pathophysiology of NAFLD/non-alcoholic steatohepatitis (NASH) is multifactorial and the mechanisms underlying the progression to advanced forms remain unclear, thereby representing a challenge to disease therapy. Despite the substantial efforts from the scientific community and the large number of pre-clinical and clinical trials performed so far, only one drug was approved by the Food and Drug Administration (FDA) to treat NAFLD/NASH specifically. This review provides an overview of available information concerning emerging molecular targets and drug candidates tested in clinical studies for the treatment of NAFLD/NASH. Improving our understanding of NAFLD pathophysiology and pharmacotherapy is crucial not only to explore new molecular targets, but also to potentiate drug discovery programs to develop new therapeutic strategies. This knowledge endeavours scientific efforts to reduce the time for achieving a specific and effective drug for NAFLD or NASH management and improve patients' quality of life.