Proteomic analysis the effectivity of photodynamic therapy on Rickettsia conorii infection

Rickettsiae (Alphaproteobacteria; Rickettsiales, Rickettsiaceae) are small (0.3- to 0.5- by 0.8- to 2.0-μm) gram-negative obligate intracellular bacteria that target vascular endothelial cells and grow within the cytoplasm of eukaryotic host cells. Arthropods such as the ticks Ixodes ricinus, Dermacentor reticulatus and D. marginatus are vectors for rickettsioses causing spotted fever and the typhus groups of diseases in humans (Sekeyová, Z., Acta Virol, 2013). Carbon quantum dots (CQDs) are a new type of fluorescent nanomaterial and are currently studied for use in photodynamic therapy (PDT) as an alternative for bacterial infections treatment. During PDT, CQDs generate superoxide, killing bacteria while mammalian cells remain intact. The cytotoxicity evaluation reveals that CQDs are bio- and blood-compatible in a wide therapeutic window (Rajendiran, K., Polymers, 2019). In this work, we studied the protein differential expression occurred in Rickettsia conorii infected VERO cells subjected to PDT. Total proteins were purified from infected cells, trypsin digested and separated using an Ultimate LC System. The mass spectrometry was performed in a Waters Synapt system and for the differential expression analysis, the ProGenesis QI software was employed. Preliminary results showed an increasing of proteins involved in the Rickettsia lipopolysaccharide biosynthesis in the first 24 h after PDT and a downregulation of proteins involved in ATP syntesis and DNA repair at 48 h and 72h after PDT.