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[Activation of mGluRI in neutrophils promotes the adherence of neutrophils to endothelial cells.] [Ariticle in Chinese]

LIU Xue-Yun, LIU Yong, LI Jin-Feng, YUE Shao-Jie, SHEN Li, LI Chen, HAN Jian-Zhong, XU Jian-Ping, FENG Dan-Dan, LIU Hui-Jun, LUO Zi-Qiang

Department of Physiology, Xiangya School of Medicine, Central South University, Changsha 410078, China； Fujian University of Traditional Chinese Medicine, Fuzhou 350108, China； Department of Pediatrics, Xiangya Hospital, Central South University, Changsha 410078, China

Abstract

L-glutamate (Glu) is an excitatory neurotransmitter in the mammalian central nervous system. Relatively much attention hasbeen paid to functional expression of Glu signaling molecules in peripheral tissues very recently. The present study tested thehypothesis that the activation of group I metabotropic glutamate receptor (mGluRI) in neutrophils stimulated neutrophils adherenceto endothelial cells by increasing the surface expression of certain adhesion molecules. Peripheral blood was obtained by venipuncturefrom healthy donors, and the neutrophils were isolated by Ficoll-Hypaque gradient centrifugation. Neutrophils floating into DMEM/F12 culture medium containing 10% fetal bovine serum were then used immediately. Immunocytochemistry and real-time quantitativeRT-PCR were used to detect the expression of mGluRI (mGluR1 and mGluR5) in neutrophils. The adherence of neutrophils to culturedhuman normal umbilical vein endothelial cells (HUVE-12) was measured by the colorimetric method. Cell surface expression ofadhesion molecule CD11a in the neutrophils was determined by flow cytometry. Immunocytochemistry and real-time quantitative RTPCRshowed that mGluR1 and mGluR5 were constitutively expressed in neutrophils. Application of mGluRI agonist S-3,5- dihydroxyphenylglycine (S-DHPG) (1×10-8-1×10-6 mol/L) showed a dose-dependent stimulatory effect on the adherence of neutrophilsto HUVE-12 (P<0.05 or P<0.01), with a maximum effect at 1×10-6 mol/L (P<0.01). Incubations as short as 30 min were sufficientto induce increased adherence after the beginning of S-DHPG treatment. Following time extension (0.5-5 h), S-DHPG (1×10-6 mol/L)increased the rate of neutrophils adhesion to HUVE-12 with a maximum effect at 0.5 h (P<0.01). However, a time-dependent effect ofS-DHPG on the rate of neutrophils adhesion to HUVE-12 was not observed during the experimental period. 1×10-6 mol/L of S-DHPGalso induced an increased surface expression of adhesion molecule CD11a (P<0.01) when neutrophils were preincubated with 1×10-6mol/L of S-DHPG for 1 h. Furthermore, the specific mGluRI antagonist (RS)-α-methyl-4-carboxyphenylglycine ((±)-MCPG, 0.5mmol/L) significantly abolished the stimulatory effect of S-DHPG (1×10-6 mol/L) on the adherence of neutrophils to HUVE-12 (P<0.01).These results suggest that the activation of mGluRI in neutrophils results in increased adhesion molecule CD11a expression andthereby promotes the adherence of neutrophils to endothelial cells.

Key words: metabotropic glutamate receptor 1; metabotropic glutamate receptor 5; neutrophils; vascular endothelial cells; cell adhesion molecules; antigens, CD11a

Received: 2010-01-18　　Accepted: 2010-03-15

Corresponding author: 罗自强　　E-mail: luozq1962@163.com

Citing This Article：

LIU Xue-Yun, LIU Yong, LI Jin-Feng, YUE Shao-Jie, SHEN Li, LI Chen, HAN Jian-Zhong, XU Jian-Ping, FENG Dan-Dan, LIU Hui-Jun, LUO Zi-Qiang. [Activation of mGluRI in neutrophils promotes the adherence of neutrophils to endothelial cells.] [Ariticle in Chinese] . Acta Physiol Sin 2010; 62 (3): 219-224 (in Chinese with English abstract).