Caracterização estrutural e funcional de peptídeos isolados da derme de Hypsiboas raniceps (Anura)

• Ano de defesa: 2018
• Autor(a) principal: Popov, Cláudia Sofia de Freitas Correia
• Orientador(a): Rezende, Taia Maria Berto
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Católica de Brasília
• Programa de Pós-Graduação: Programa Stricto Sensu em Ciências Genômicas e Biotecnologia
• Departamento: Escola de Saúde e Medicina
• País: Brasil
• Palavras-chave em Português: Peptídeos; H. raniceps; Anti-inflamatórios; Imunomoduladores
• Palavras-chave em Inglês: Immunomodulatory; Anti-inflammatory; Peptides
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS
• Link de acesso: https://bdtd.ucb.br:8443/jspui/handle/tede/2497

Anurans represent a valuable source of bioactive molecules. These substances constitute a primary line of defense against predators and pathogenic microorganisms such as bacteria and fungi. Secreted peptides by granular glands represent a source of potential pharmacological agents with diverse functions. The structural and functional characterization of these biomolecules allows a better understanding of their function and biotechnological applications. Thus, in this work, the new peptides were isolated from H. raniceps with variable size between 11 and 16 amino acid residues, all of which contain two cysteines in their primary structure and with immunomodulatory activity: AC12, DK16 and RC11. A nuclear magnetic resonance analysis allowed to determinate a structure of these β-sheet molecules, as well as the presence of disulfide bridges that gives stability to the peptides. Regarding the structural analysis, none of the samples showed effective antimicrobial action. The immunomodulatory action profile of the samples was also checked. For this, a cytotoxicity essay of the molecules was initially tested. AC12 and DK16 did not reduce the viability of RAW 264.7 cells, decreasing inflammatory markers such as NO, IL-12 and TNF-α. They also decreased IL-10 production, a pro-inflammatory cytokine, but associated with several types of neoplasms. The peptide RC11 was shown to be toxic in RAW 264.7 strain. However, all samples were shown to be safe when tested at different concentrations in erythrocytes of Balb/c mice, presenting low hemolysis rates. In the in vivo tests, the three peptides reduced the paw edema caused by carrageenan, standing out the peptide AC12. Such data were corroborated by histological analysis of paw tissue. Regarding the immunomodulatory action with carrageenan-induced peritonitis assay, peptide AC12 was again the most significant, reducing the TNF-α dosed from the peritoneal lavage and increasing IL-10. In conclusion, AC12 has shown to be a good candidate as an anti-inflammatory agent, and could be used in the treatment of several inflammatory conditions.