Ultrastructural Study of Mitochondrial Dynamics (MD) of Autologous Human Leukocytes in ETosis In Vitro

Background: Extracellular Traps (ETosis) are considered an immune response mechanism involving a novel form of cell death through the formation of Extracellular Traps (ETs). Currently, ETs are understood as a defense mechanism that does not necessarily involve cell death. They are composed of a set of nuclear and cytoplasmic proteins embedded in a fibrillar network of nuclear or mitochondrial DNA. Objective: In vitro study of Mitochondrial Dynamics (MD), in human leukocytes subjected to ETosis. Methods: Heparinized peripheral blood samples were obtained from healthy donors with ethical consent and autologous total leukocytes were isolated and cultured. In vitro ETs were generated using LPS or fMLP MD was characterized by ultrastructural analysis using TEM. The ETs were visualized using TEM and IF microscopy. MD were quantified using FIJI software. Statistical analysis: paired Student’s t-test. Results: In paired samples of autologous cultures, no significant differences (p > 0.05) were observed in area and number of mitochondria per cell. Signs of mitochondrial redistribution were evident in lymphocytes polarized toward the immune synapse (IS), and mitochondrial fission and fusion phenomena were visualized. Conclusions: MD is implicated in various diseases and in immune cells undergoing ETosis, it could be considered a potential therapeutic target.