Multi-walled carbon nanotubes induce apoptosis via mitochondrial pathway and scavenger receptor.
We have demonstrated previously that the acid-treated multi-walled carbon nanotubes (aci-MWCNTs) and taurine functionalized MWCNTs (tau-MWCNTs) induced differential pulmonary toxicity in mice after instillation exposure. In order to compare differences of cytotoxicity between the aci- and tau-MWCNTs, RAW 264.7 cells (a murine macrophage cell line) were chosen to be exposed to the aci- and tau-MWCNTs at concentrations of 0, 5, 20, 40, and 80μg/ml for 12 or 24h respectively. The results showed that although the aci- and tau-MWCNTs induced only mild decrease in cell viability to RAW 264.7 cells, the two types of MWCNTs elicited significant increase in apoptosis and decreased ability in cellular phagocytosis. Moreover, by using the specific inhibitors, we found that the scavenger receptors (SR) and caspase-9 were actively involved in the apoptosis induced by the aci- and tau-MWCNTs. The taurine functionalized MWCNTs (tau-MWCNTs) showed less cytotoxicity and apoptotic effect to RAW 264.7 cells than those of aci-MWCNTs. Taken together, the results indicated the important role of scavenger receptors and mitochondria in the apoptosis induced by MWCNTs.
Department of Occupational and Environmental Health, School of Public Health, Peking University, #38 Xueyuan Rd., Beijing 100191, China. xiangwang@uda.edu
Xiang
X
Wang
Jian
J
Guo
Tian
T
Chen
Haiyu
H
Nie
Haifang
H
Wang
Jiajie
J
Zang
Xiaoxing
X
Cui
Guang
G
Jia
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053453:Caspase 9 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000502:physiology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000633:toxicity*; D010587:Phagocytosis / Q000187:drug effects; D051116:Receptors, Scavenger / Q000378:metabolism*
D037742:Nanotubes, Carbon; D051116:Receptors, Scavenger; D045304:Cytochromes c; D053453:Caspase 9