Glucose-6-phosphate dehydrogenase (G6PD)-deficient epithelial cells are less tolerant to infection by Staphylococcus aureus.
Glucose-6-phosphate dehydrogenase (G6PD) is a key enzyme in the pentose phosphate pathway and provides reducing energy to all cells by maintaining redox balance. The most common clinical manifestations in patients with G6PD deficiency are neonatal jaundice and acute hemolytic anemia. The effects of microbial infection in patients with G6PD deficiency primarily relate to the hemolytic anemia caused by Plasmodium or viral infections and the subsequent medication that is required. We are interested in studying the impact of bacterial infection in G6PD-deficient cells. G6PD knock down A549 lung carcinoma cells, together with the common pathogen Staphylococcus aureus, were employed in our cell infection model. Here, we demonstrate that a lower cell viability was observed among G6PD-deficient cells when compared to scramble controls upon bacterial infection using the MTT assay. A significant increase in the intracellular ROS was detected among S. aureus-infected G6PD-deficient cells by observing dichlorofluorescein (DCF) intensity within cells under a fluorescence microscope and quantifying this signal using flow cytometry. The impairment of ROS removal is predicted to enhance apoptotic activity in G6PD-deficient cells, and this enhanced apoptosis was observed by annexin V/PI staining under a confocal fluorescence microscope and quantified by flow cytometry. A higher expression level of the intrinsic apoptotic initiator caspase-9, as well as the downstream effector caspase-3, was detected by Western blotting analysis of G6PD-deficient cells following bacterial infection. In conclusion, we propose that bacterial infection, perhaps the secreted S. aureus α-hemolysin in this case, promotes the accumulation of intracellular ROS in G6PD-deficient cells. This would trigger a stronger apoptotic activity through the intrinsic pathway thereby reducing cell viability when compared to wild type cells.
Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
Yi-Ting
YT
Hsieh
Mei-Hui
MH
Lin
Hung-Yao
HY
Ho
Lei-Chin
LC
Chen
Chien-Cheng
CC
Chen
Jwu-Ching
JC
Shu
D017209:Apoptosis; D045744:Cell Line, Tumor; D024881:Drug Resistance, Bacterial; D004847:Epithelial Cells / Q000166:cytology / Q000201:enzymology* / Q000382:microbiology*; D005954:Glucosephosphate Dehydrogenase / Q000187:drug effects / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000378:metabolism; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D009336:Necrosis; D017382:Reactive Oxygen Species / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects / Q000502:physiology*; D014640:Vancomycin / Q000494:pharmacology
D006460:Hemolysin Proteins; D017382:Reactive Oxygen Species; D014640:Vancomycin; D005954:Glucosephosphate Dehydrogenase