Hypoxic induction of interleukin-8 gene expression in human endothelial cells.
Because leukocyte-mediated tissue damage is an important component of the pathologic picture in ischemia/reperfusion, we have sought mechanisms by which PMNs are directed into hypoxic tissue. Incubation of human endothelial cells (ECs) in hypoxia, PO2 approximately 14-18 Torr, led to time-dependent release of IL-8 antigen into the conditioned medium; this was accompanied by increased chemotactic activity for PMNs, blocked by antibody to IL-8. Production of IL-8 by hypoxic ECs occurred concomitantly with both increased levels of IL-8 mRNA, based on polymerase chain reaction analysis, and increased IL-8 transcription, based on nuclear run-on assays. Northern analysis of mRNA from hypoxic ECs also demonstrated increased levels of mRNA for macrophage chemotactic protein-1, another member of the chemokine superfamily of proinflammatory cytokines. IL-8 gene induction was associated with the presence of increased binding activity in nuclear extracts from hypoxic ECs for the NF-kB site. Studies with human umbilical vein segments exposed to hypoxia also demonstrated increased elaboration of IL-8 antigen compared with normoxic controls. In mice exposed to hypoxia (PO2 approximately 30-40 Torr), there was increased pulmonary leukostasis, as evidenced by increased myeloperoxidase activity in tissue homogenates. In parallel, increased levels of transcripts for IP-10, a murine homologue in the chemokine family related to IL-8, were observed in hypoxic lung tissue. Taken together, these data suggest that hypoxia constitutes a stimulus for leukocyte chemotaxis and tissue leukostasis.
Karakurum
M
M
Department of Physiology, Columbia University, College of Physicians and Surgeons, New York 10032.
Shreeniwas
R
R
Chen
J
J
Pinsky
D
D
Yan
S D
SD
Anderson
M
M
Sunouchi
K
K
Major
J
J
Hamilton
T
T
Kuwabara
K
K
Rot
A
A
Nowygrod
R
R
Stern
D
D
D000818:Animals; D001483:Base Sequence; D015687:Cell Hypoxia; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics*; D007962:Leukocytes / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism
D016209:Interleukin-8; D016328:NF-kappa B