Special Laboratory for Applied Toxinology (LETA)


 Editor de Conteúdo

Scientific Leadership

Hugo Aguirre Armelin – haarmeli@iq.usp.br

Functional Proteomics Laboratory
Inácio Junqueira de Azevedo – ijuncaze@butantan.gov.br
Julia Pinheiro Chagas da Cunha – jcunha@butantan.gov.br
Pedro Ismael da Silva Junior – pisjr@butantan.gov.br
Robson Lopes de Melo – robson@butantan.gov.br
Solange Maria de Toledo Serrano – solange.serrano@butantan.gov.br
Vanessa Rioli – vrioli@butantan.gov.br

Associate Researchers
Antonio Carlos Martins de Camargo – acmcamargo@butantan.gov.br
Marcella Faria de Almeida Prado – marcella@butantan.gov.br

Special Laboratory for Cell Cycle
Hugo Aguirre Armelin – haarmeli@iq.usp.br
Maria Carolina Elias – carol@butantan.gov.br

Special Laboratory for Pain and Signaling
Gisele Picolo – gipicolo@butantan.gov.br
Yara Cury – yarac@butantan.gov.br

Immunoregulation Laboratory
Carla Lima da Silva – carlalima@butantan.gov.br
Mônica Valdyrce dos Anjos Lopes Ferreira – lopesferreira@butantan.gov.br​

general objective of the unit

The LETA laboratories concertedly seek excellence in toxin research, innovation and diffusion. Conceptually, the group is guided by the notion of that innovation is a by-product of competitive scientific research. In this line, success in the exploration of toxins as possible sources of new drugs and important molecular tools in pathophysiology depends and runs on the research projects in correlated areas, integrally developed by the Division's laboratories. Operationally, the laboratories share technical competences and equipment, allowing a sustained and synergistic development of research projects.

research areas in the LETA


Proteomics applied to the analysis of snake venom proteinase interactions with cellular and plasmatic targets and the analysis of the proteome/peptidome variability of snake venoms
The complexity and the variety of snake poison toxins' molecular targets make them important biological tools and candidates for therapeutic agent design. Serine proteinases (SP) act on the coagulation, fibrinolysis and platelet systems, causing a hemostatic imbalance. Metaloproteinase (MP) activities are associated with the disruption of hemostasis generated for pro- and anti-coagulating effects and with the local or systemic hemorrhage. This group uses proteomic approaches to analyze the systemic effects of poison proteinases, with a focus on the analysis of the interaction of HF3, a hemorrhagic MP, with platelets and endothelial cell membrane proteins, and analysis of macrophages and the signaling events caused by the cleavage of the PAR1 receptor by PA-BJ, a SP that activates platelet aggregation. In parallel, we use electrophoresis and mass spectrometry approaches to analyze the composition and the variability of the snake poison proteome/peptidome.


Study of the trigger factors and the essential intracellular signals in the activation of subtype T and B lymphocytes in the generation of immune memory 

The immune memory is a hallmark of the adaptive immune response in superior vertebrates and is responsible for the long-term immunity against an enormous variety of infectious agents. The group has been performing studies that aim at a larger understanding of dendritic cells' modulating capacity and the standard of innate receptors' expression in view of the possibility of modulating the functional quality of memory T cells; the role of cytokines and the underlying mechanisms in the differentiation of different T and B memory lymphocytes for the optimization of vaccine reinforcement strategies; and the function of T lymphocytes (Th1, Th2, Th9, Th17, Treg) in establishing the vaccine factors that are effective against pathogens.


Study of the cellular and molecular immune mechanisms underlying inflammatory phenomena 

Since 1996, the research group has been developing projects with the venoms of poisonous fish. Besides generating important pathophysiological knowledge about envenomation, the biochemical nature of the toxins and the therapy for the control of the injuries, the results obtained also facilitated a view of the complex existing network of interactions in the innate immune system. Consequently, research began to better understand the cellular and molecular immunological mechanisms underlying the inflammatory phenomena and the importance of these for the tissue function in some murine experimental models. Using the poisons or their toxins, the group has been able to establish adequate models for the study of the cellular compartment of the innate or inflammatory response.


Cell cycle 
The group studies the biochemical, molecular and cellular mechanisms that control the cell cycle. Currently, the group is concentrating on mechanisms the pre-replication steps that guarantee the unique and complete replication of the genome in the Trypanosoma cell cycle; signaling pathways triggered by the FGF receptors (fibroblast growth factor) that control the G0/G1→S and G2→M transitions of the cell cycle in mammal cell lines. Parallel to this experimental approach, mathematical-computational models of the signaling networks and metabolic pathways underlying the control of the cell cycle are developed.


Pain and signalling 
The group develops studies in the area of pain and analgesia using animal toxins as tools for standardizing new experimental models used in studies in this area, for the approach to the mechanisms involved in the nociceptive phenomena and their control, and for the design of pharmaceuticals with analgesic activity. The research areas refer to: (a) The study of the mechanisms involved in the analgesic/anti-inflammatory effects of animal venoms and toxins, projects that have contributed to the characterization of new compounds with analgesic and/or anti-inflammatory activity with possible therapeutic applications, and also for the understanding of the cellular and molecular mechanisms involved in the control of pain/inflammation; (b) Study of the pathophysiology of induced pain/inflammation by venoms/animal toxins which mainly use toxins with A2 phospholipase activation or substances capable of interfering with ion channels. The results have favored the understanding of the pathophysiology of the local effects observed in animal poisonings and the physiology and pathophysiology of pain and inflammation. Additionally, these studies have facilitated the use of animal toxins as tools for the development of experimental models for the study of pain and inflammation.


Animal venoms are solutions rich in proteins of enormous variability. The global identification of their composition is an important challenge for understanding of their function and for the discovery of new molecules. To do this, we apply the approach of transcriptomics, that is, the sequencing of cDNA libraries from mRNAs expressed in the venom glands, be it through conventional or new generation sequencing (NGS) techniques, with the possibility of even complementing these with proteomic studies. Having already investigated diverse animals, we have focused on the characterization of snake poisons from the Colubridae family as well as the investigation of microRNAs in recent years.  This has allowed us to discover unknown toxins and understand the evolutionary processes of the diversification of venoms in addition to the molecular characterization of the glandular epithelium.


Proteomic analysis and cell cycle  
In this project we intend to study proteomics, phosphoproteomics and epigenetic alterations throughout the cell cycle and cellular senescence in mouse cells exposed, or not, to FGF2. Our main approach will be to characterize such alterations in proteins located in the cellular nucleus. To do this, we are establishing protocols for cell fractionation; peptide quantification;  enrichment of phosphorylated and acetylated peptides in order to explore the dynamics of these alterations using mass spectrometry. Moreover, we will analyze whether epigenetic alterations, such as post-translational modifications in histones, occur throughout the cell cycle or during the ageing process.


Our group's main goal is to investigate the cellular and molecular biology of oligopeptidases (Former TOP, Neurolysin, NEP, ECE, etc...) through the development of biochemical experiments emphasizing molecular biology and focusing on the following subjects: bioactive enzymology of oligopeptidases, recombinant peptides, expression of oligopeptidases (in bacteria and yeast) and identification of possible new substrates and/or oligopeptidase inhibitors present in animal poisons or tissue.


Evolution and biodiversity of antimicrobial peptides in arachnids 
The research on molecules derived from Brazilian flora and fauna can be valuable, given that evolution itself has already selected them from a vast spectrum of substances that were efficient in the fight against infection, as they are promising candidates for the development of drugs in the fight against pathogens that are resistant to conventional antibiotics. In this sense, we are working on the survey and characterization of molecules that have antimicrobial activity in arachnids, one of the oldest groups of animals, representatives of which appeared in the Silurian, more than 350 million years ago. These animals live in environments with large proliferations of pathogenic microorganisms, therefore, one of the factors leading to the success of the group could be the presence of antimicrobial molecules.


Synthesis of unnatural amino acids, peptides and their mimetics applied to the development of new molecules against target proteins of interest. These proteins can be derived from poisons, animal secretions, as well as from humans. The studies are guided by kinetic and/or inhibitory interaction and in silico analysis.