Phosphatidylserine enhances recognition and uptake of single-walled carbon nanotubes by rat brain microglial cells.
Feng-W; Tyurina-YY; Bayir-H; Shvedova-AA; Kagan-VE
Toxicologist 2007 Mar; 96(1):289
Single-walled carbon nanotubes (SWCNT) are a class of nanosized materials with wide applications in industry and medicine. Inhaled SWCNT have been shown to cause a robust inflammatory and oxidative stress response in the lung and cardiovascular system. Interactions with phagocytozing cells determine SWCNT elimination or spreading into different tissues. The challenge is how to make nanotubes delivered specifically to the target site. We established that macrophages do not effectively recognize non-functionalized SWCNT but readily engulf SWCNT coated with phosphatidylserine (PS), an "eat-me" signal for phagocytes. In the brain, important immunological functions are associated with the ability of microglial cells to exert phagocytic activity. As inhaled nanoparticles have been detected in the brain we were interested to study interactions of SWCNT with microglial cells. Microglial cells were isolated from postnatal rat brains and identified with CD11 antibody. Primary cultures were obtained with 70% microglial cell population which could be activated by lipopolysacharide (LPS) to produce NO revealed by labeling of cells with a specific fluorogenic reagent, DAF-2DA. Further we studied phagocytosis of SWCNT by microglial cells. Cells were incubated with SWCNT coated with either fluorescently labeled nitrobenzoxadiazole (NBD)-PS or NBD-phosphatidylcholine (PC) for 2h. Fluorescent microscopy was applied and revealed that NBD-PS-SWCNT were a more preferred target of recognition and uptake by microlgial cells than NBD-PC-SWCNT. Control experiments were performed to confirm that NBD-phospholipids remained bound to SWCNT. Thus, similar to macrophages, microglial cells utilize PS as a signal for effective recognition and engulfment of SWCNT.
Cell-alteration; Cell-damage; Cellular-reactions; Cell-biology; Cell-function; Cell-metabolism; Oxidation; Oxidative-metabolism; Oxidative-processes; Inhalation-studies; Animal-studies; Microscopic-analysis; Microchemistry; Microbiology; Nanotechnology
The Toxicologist. Society of Toxicology 46th Annual Meeting and ToxExpo, March 25-29, 2007, Charlotte, North Carolina
University of Pittsburgh at Pittsburgh