Symposia Descriptions

Peroxiredoxins, From Basic Biochemistry to Clinical Applications 

Chairs: Flavia Meotti, PhD, Universidade de São Paulo, Brazil & Gerardo Ferrer-Sueta, PhD, Universidad de la República, Uruguay

More than three decades have elapsed since the formal naming as Peroxiredoxins of the then new family of peroxidases, and in the interim the number of their known functions has grown. From their original antioxidant role, Peroxiredoxins have shown the roles of the sensing of oxidants, chaperones/holdases and, more recently, in redox signaling, by relaying of electrons via thiol disulfide reactions with target molecules. The knowledge on Peroxiredoxin biochemistry and physiology has expanded extremely fast, and that growth has involved research groups of our region, such as those of Luis Netto and Ohara Augusto in Brazil and those of Rafael Radi and Ana Denicola in Uruguay. That pioneer Peroxiredoxin research in the region has produced new generations of young researchers whose names appear in the more than a dozen annual articles that have consistently been published by, or with the collaboration, of South American groups in the past decade. The scope of our proposed Symposium on Peroxiredoxins is to encompass the breadth of research including as senior speakers one addressing a very basic enzymological approach of Peroxiredoxin function and the other one presenting the latest results of Peroxiredoxin involvement in cancer. We hope that the proposed Symposium on Peroxiredoxins will be an optimal opportunity for researchers to meet and share their findings from the basic biochemistry to the physiological roles and clinical applications of peroxiredoxins.

Invited Speakers:
Interactions of 1-Cys Peroxiredoxins and Ascorbate in Pathogenic Microorganisms’ Response to Hydroperoxides and Seed Biology
Luis E. S. Netto, PhD, Universidade de São Paulo, Brazil
Interactions Between Peroxiredoxins and Other Mitochondrial Compounds: Kinetics, Reaction Mechanisms and Effects on Hyperoxidation
Madia Trujillo, MD, PhD, Universidad de la República, Uruguay

The Endoplasmic Reticulum Redoxome: An Emerging Scenario for Multiple Cell Functions

Chairs: Francisco RM Laurindo, Md, PhD, Heart Institute (Incor), University of Sao Paulo School of Medicine and Lei Wang, PhD, State Key Laboratory of Biomacromolecules

The Endoplasmic Reticulum (ER) is the largest cellular organelle and exerts crucial functions in protein folding and processing, lipid metabolism, calcium regulation, among many others. ER-dependent redox processes are central to the regulation of ER activities, but also extend to several related extra-ER activities. These include the increasingly evident regulation of extracellular redox processes by the ER, particularly the secretion and cell-surface translocation of ER thiol oxidoreductases, which mediates intercellular redox communication related to cell adhesion processes, thrombosis, platelet adhesion, mechanoadaptation and vascular remodeling. In addition, a number of other intracellular functions, including Nox regulation, cytoskeleton organization and cancer cell survival, depend on ER-associated redox processes, including in particular the recently described reflux of ER proteins to the cytosol. The ER also establishes contacts with plasma membrane, mitochondria, peroxisomes, lysosomes, endosomes and other organelles, allowing extensive communications at least in part related to redox pathways, merging with calcium exchange. The ER redoxome, thus, comprises an extensive network of small molecule oxidants (such as hydrogen peroxide from the ER lumen), thiol oxidoreductases (Ero1 and PDI family proteins) and thiol proteins (e.g., Prx4, Gpx7, Gpx8), in addition to glutathione exchange pathways. This symposium aims to discuss state-of-the-art developments regarding mechanisms and implications of ER-dependent redox processes. This should be a valuable opportunity to raise the awareness of this area, which is to some extent yet emerging in the redox community. Moreover, given the broadness and importance of the theme, as well as the excellence of speakers, the symposium is likely to motivate many other investigators of the redox community towards collaborative efforts and inter-disciplinary scientific progress.

Invited Speakers:
The ER Redoxtasis: From Basic Research to the Intervention of Aging and Diseases
Lei Wang, PhD, State Key Laboratory of Biomacromolecules
Spatial Redoxome in Motion: Mechanisms of Cysteine-Mediated Protein Rewiring inCancer Survival
Aeid Igbaria, PhD, Ben-Gurion University of the Negev

Oxidative Stress and Lipid Signaling in Inflammation and Cancer: Mechanisms and Clinical Implications

Chairs: Sayuri Miyamoto, University of Sao Paulo and Homero Rubbo, Facultad de Medicina, Universidad de la República

Oxidative stress (OxS) and lipid-derived mediators are increasingly recognized as critical regulators in the development and progression of chronic diseases, including atherosclerosis and cancer. Rather than acting solely as damaging agents, oxidative stress markers and lipid oxidation products can exert protective or pathogenic effects depending on context, timing, and cellular environment. This symposium will highlight recent advances that elucidate the complex and often dual roles of oxidative stress in modulating inflammation, immune cell metabolism, and tumorigenesis. By integrating mechanistic studies from experimental models with large-scale epidemiological findings, the session will provide a multidimensional view of how redox-sensitive pathways and lipid peroxidation products influence disease initiation and trajectory. Specific focus will be given to the modulation of macrophage function in atherosclerosis and the time-dependent relationship between systemic oxidative stress and colorectal cancer risk.

Symposium Objectives:

• To present novel mechanistic insights into how lipid-derived oxidative mediators regulate immune cell metabolism and inflammatory responses in cardiovascular disease.
• To highlight human epidemiological data supporting an inverse, time dependent relationship between systemic oxidative stress and colorectal cancer risk.
• To examine the dual and dynamic nature of oxidative stress in the pathogenesis and resolution of chronic diseases.
• To stimulate discussion on the translational implications of redox biology for therapeutic innovation and public health strategies.

This symposium will be particularly relevant to those interested in understanding how oxidative stress and lipid signaling intersect to influence chronic disease risk and progression.

Invited Speakers:
Targeting Lipid Biomarkers in Cancer Through Mass Spectrometric AnalysisTargeting Lipid Biomarkers in Cancer Through Mass Spectrometric Analysis
Ginger Milne, PhD, Vanderbilt University
Nitrolipids, Monocyte Reprogramming, and Scavenger Receptors: A New Link to Atherosclerosis
Gustavo Bonacci, PhD, Universidad Nacional de Córdoba

Redox Biology in Platelets: Mechanisms, Organelles, and Therapeutic Strategies

Chairs: Eduardo Fuentes Quinteros, PhD, Universidad de Talca, Talca-Chile and Antonio Marcus de Andrade Paes, Universidade Federal do Maranhao

Platelets play a fundamental role in hemostasis and thrombosis, with their activation and aggregation tightly regulated by redox signaling. Emerging evidence highlights the influence of redox metabolism on platelet function in both physiological and pathological conditions, including cardiovascular disease, inflammation, and oxidative stress-related disorders. This symposium will explore the intricate redox mechanisms that govern platelet activation and aggregation, with a particular focus on the contributions of mitochondria and other organelles, such as peroxisomes and the endoplasmic reticulum.

Recent studies have underscored the role of reactive oxygen species (ROS) and redox enzymes in modulating platelet responses, revealing new opportunities for targeting redox pathways in antiplatelet therapy. We will discuss how oxidative modifications of key platelet proteins affect their function and how redox-based signaling pathways intersect with classical platelet activation cascades. Furthermore, this session will highlight the latest advancements in the development of antiplatelet drugs designed to target redox mechanisms, offering novel therapeutic strategies for thrombotic diseases.

By integrating recent discoveries with translational perspectives, this symposium aims to provide a comprehensive understanding of redox biology in platelets. It will foster discussions on emerging therapeutic applications and future research directions, making it particularly relevant for researchers in platelet biology, redox signaling, cardiovascular health, and drug development.

Invited Speakers:
Redox Regulation of Platelet Function: Novel Synthetic and Natural Compounds as Therapeutic Strategies
Andrés Trostchansky, PhD, Facultad de Medicina, Universidad de la República
Modulating Platelet Function in Frailty: Unraveling Mechanisms and Therapeutic Opportunities
Eduardo Fuentes, PhD, Universidad de Talca, Talca-Chile

Photoinduced Electron Transfer in Biological Systems

Chairs: Carolina Lorente, PhD, Universidad Nacional de La Plata, CONICET and Erick Leite Bastos, PhD, Universidade de São Paulo

Exposure to the sun is not always harmful to living beings, which depend on photosynthesis for life to be possible. However, it is well-known that exposure of living systems to solar or artificial electromagnetic radiation causes oxidative stress, since the interaction of suitable molecules with electromagnetic radiation generates reactive species through photoinduced electron transfer reactions that, although they are essential for generating energy in plants, can cause damage to biomolecules relevant for physiological functions.

The mechanism involved in photoinduced electron transfer can be either direct or indirect, depending on which molecule is ultimately damaged. During direct mechanisms, the molecule absorbs radiation and is transformed into reactive species yielding oxidation products. On the contrary, during indirect mechanisms, the absorbing molecule is excited to higher energy states and reacts with a second molecule or molecular oxygen to form reactive species, which in a subsequent step reacts with surrounding molecules to oxidize them.

In living organisms, almost all biomolecules are susceptible to oxidation, through direct and indirect mechanisms. The main targets for photoinduced damage are proteins, especially those present in eyes and skin. The oxidation of proteins can result in oxidation of amino acids, fragmentation, generation of dimers and aggregates, loss of structure and function. Also, DNA molecules can be oxidized by radiation, generating mutations which are related to the development of skin cancer, among which melanoma should be highlighted, and are directly related to sun exposure. This symposium will present studies related to the damage caused by electromagnetic radiation, especially due to sun exposure. The proposed speakers are experts in the subject and will present to the audience evidence about the damage caused by photoinduced electron transfer.

Invited Speakers:
Mapping of Oxidative Modifications on Proteins Arising from Photo-oxidation
Michael Davies, PhD, Panum Institute, University of Copenhagen
Degradation of Biomolecules Photoinduced by Pterins: a Model to Understand Type I Photosensitized Oxidations
Andrés Héctor Thomas, Universidad Nacional de La Plata

The Janus-Faced Heme: Heme Proteins as Producers and Scavengers of Reactive Oxygen and Nitrogen Species

Chairs: Paola Corti, PhD, University of Maryland and Jesus Tejero, PhD, University of Pittsburgh

Heme proteins are pivotal for the biology of reactive oxygen and nitrogen species (ROS/RNS). Through their role in oxygen transport and delivery, oxidative phosphorylation, and the generation (and scavenging) of ROS/RNS, these proteins appear in almost every biological free radical-related pathway. Heme proteins include some of the most researched proteins in biology -myoglobin and hemoglobin. Despite the longstanding interest in heme proteins, novel vertebrate heme proteins -neuroglobin, cytoglobin, androglobin- have been discovered in the last 25 years, and the known globins have been found in unsuspected tissues and cellular locations, challenging our existing knowledge. In this session we focus on recent advances that challenge the general conceptions about the role of heme proteins in chemical biology, from roles in development to vascular biology, light sensing and beyond

Invited Speakers:
Cytoglobin Nitric Oxide-dependent and Independent Functions in the Cardiovascular System
Dennis Stuehr, PhD, Cleveland Clinic
An Endogenous Photonic Signaling Pathway in the Mammalian Brain Modulated by Reactive Oxygen and Nitrogen Species
Yvette Yien, PhD, University of Pittsburgh