Signal pathways underlying homocysteine-induced production of MCP-1 and IL-8 in cultured human whole blood.
OBJECTIVE
To elucidate the mechanisms underlying homocysteine (Hcy)-induced chemokine production.


METHODS
Human whole blood was pretreated with inhibitors of calmodulin (CaM), protein kinase C (PKC), protein tyrosine kinase (PTK), mitogen-activated protein kinase (MAPK), and NF-kappaB and activators of PPARgamma for 60 min followed by incubation with Hcy 100 micromol/L for 32 h. The levels of mitogen chemokine protein (MCP)-1 and interleukin-8 (IL-8) were determined by enzyme-linked immunosorbant assay (ELISA).


RESULTS
Inhibitors of PKC (calphostin C, 50-500 nmol/L and RO-31-8220, 10-100 nmol/L), CaM (W7, 28-280 micromol/L), ERK1/2 MAPK (PD 98059, 2-20 micromol/L), p38 MAPK (SB 203580, 0.6-6 micromol/L), JNK MAPK (curcumin, 2-10 micromol/L), and NF-kappaB (PDTC, 10-100 nmol/L) markedly reduced Hcy 100 micromol/L-induced production of MCP-1 and IL-8 in human cultured whole blood, but the inhibitors of PTK (genistein, 2.6-26 micromol/L and tyrphostin, 0.5-5 micromol/L) had no obvious effect on MCP-1 and IL-8 production. PPARgamma activators (ciglitazone 30 micromol/L and troglitazone 10 micromol/L) depressed the Hcy-induced MCP-1 production but not IL-8 production in the cultured whole blood.


CONCLUSIONS
Hcy-induced MCP-1 and IL-8 production is mediated by activated signaling pathways such as PKC, CaM, MAPK, and NF-kappaB. Our results not only provide clues for the signal transduction pathways mediating Hcy-induced chemokine production, but also offer a plausible explanation for a pathogenic role of hyperhomocysteinemia in these diseases.
Zeng
Xiao-kun
XK
Institute of Vascular Medicine, Peking University Third Hospital, Beijing 100083, China.
Guan
You-fei
YF
Remick
Daniel G
DG
Wang
Xian
X
D002147:Calmodulin / Q000037:antagonists & inhibitors; D018932:Chemokine CCL2 / Q000378:metabolism*; D006710:Homocysteine / Q000494:pharmacology*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D015398:Signal Transduction
D002147:Calmodulin; D018932:Chemokine CCL2; D016209:Interleukin-8; D016328:NF-kappa B; D006710:Homocysteine; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases