Analysis of cytosolic mtDNA release during Staphylococcus aureus infection.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the principal human pathogens, causing severe infections in skin wounds. MRSA infection triggers a cell response mainly by mitochondrial-mediated pathway, resulting in mitochondrial outer membrane permeabilization, extrusion of the mitochondrial inner membrane into the cytoplasm, and then spillage of mitochondrial DNA (mtDNA) into the cytoplasm. The cell recognizes the discharged cytosolic mtDNA (cmtDNA) as "not-itself" because of mtDNA properties and triggers cascade events, such as the activation of inflammasomes. Here, we detail a method to detect and measure the mtDNA release into the cytoplasm in immortalized keratinocytes (HaCaT cells), after the infection with MRSA at different time points after the infection.