Multi-walled carbon nanotubes act as a chemokine and recruit macrophages by activating the PLC/IP3/CRAC channel signaling pathway.
The impact of nanomaterials on immune cells is gaining attention but is not well documented. Here, we report a novel stimulating effect of carboxylated multi-walled carbon nanotubes (c-MWCNTs) on the migration of macrophages and uncover the underlying mechanisms, especially the upstream signaling, using a series of techniques including transwell migration assay, patch clamp, ELISA and confocal microscopy. c-MWCNTs dramatically stimulated the migration of RAW264.7 macrophages when endocytosed, and this effect was abolished by inhibiting phospholipase C (PLC) with U-73122, antagonizing the IP3 receptor with 2-APB, and blocking calcium release-activated calcium (CRAC) channels with SK&F96365. c-MWCNTs directly activated PLC and increased the IP3 level and [Ca2+]ilevel in RAW264.7 cells, promoted the translocation of the ER-resident stromal interaction molecule 1 (STIM1) towards the membranous calcium release-activated calcium channel modulator 1 (Orai1), and increased CRAC current densities in both RAW264.7 cells and HEK293 cells stably expressing the CRAC channel subunits Orai1 and STIM1. c-MWCNTs also induced dramatic spatial polarization of KCa3.1 channels in the RAW264.7 cells. We conclude that c-MWCNT is an activator of PLC and strongly recruits macrophages via the PLC/IP3/CRAC channel signaling cascade. These novel findings may provide a fundamental basis for the impact of MWCNTs on the immune system.
Department of Physiology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, China.|Key Laboratory for Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease and the Institute of Cardiovascular Research, Southwest Medical University, Luzhou, 646000, China.
Hui
H
Li
Key Laboratory for Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease and the Institute of Cardiovascular Research, Southwest Medical University, Luzhou, 646000, China.
Xiao-Qiu
XQ
Tan
Department of Pathophysiology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, China.
Li
L
Yan
Key Laboratory for Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease and the Institute of Cardiovascular Research, Southwest Medical University, Luzhou, 646000, China.
Bo
B
Zeng
Department of Biomedical Engineering, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, China.
Jie
J
Meng
Department of Biomedical Engineering, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, China.
Hai-Yan
0000-0002-7287-9048
HY
Xu
Department of Physiology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, China. caojimin@126.com.
Ji-Min
JM
Cao
D000818:Animals; D000071739:Calcium Release Activated Calcium Channels / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects*; D016207:Cytokines / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D018613:Microscopy, Confocal; D037742:Nanotubes, Carbon; D018408:Patch-Clamp Techniques; D000067996:RAW 264.7 Cells; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000378:metabolism*
D000071739:Calcium Release Activated Calcium Channels; D016207:Cytokines; D053496:Inositol 1,4,5-Trisphosphate Receptors; D037742:Nanotubes, Carbon; D010738:Type C Phospholipases