Up regulation of plasminogen activator inhibitor 2 (PAI-2) in response to alpha-lactalbumin

H Ritchie, E A Schulte, N A Booth

Research output: Contribution to journalArticle

Abstract

U937 cells, a monocyte-like cell line, are a potent source of plasminogen activator inhibitor 2 (PAI-2) particularly following stimulation with a variety of agents. Lactalbumin enzymatic hydrolysate (LEH) can be used as an alternative to fetal calf serum (FCS) during culture of cells. Here, we report an up-regulation of PAI-2 synthesis following treatment of U937 cells with LEH and purified alpha-lactalbumin. Secretion of PAI-2 antigen into the culture medium was found to increase over time following growth of U937 cells in medium containing LEH (1%) compared to medium alone or containing FCS. The possibility that undigested lactalbumin was present in LEH was then examined. A potent increase in secreted and intracellular PAI-2 was seen following stimulation of U937 cells with purified alpha-lactalbumin. This effect was both dose- and time-dependent. Northern blotting confirmed that the up-regulation in PAI-2 was at the level of mRNA. Basal levels of PAI-2 were up-regulated by an analogue of cAMP, whereas there was no further effect on alpha-lactalbumin stimulated PAI-2. Lactalbumin is another agent that up-regulates the synthesis of PAI-2, an effect that influences the study of PAI-2 in cultured cells.

Original languageEnglish
Pages (from-to)17
Number of pages7
JournalFibrinolysis and Proteolysis
Volume13
Publication statusPublished - 1999

Keywords

  • PERIPHERAL-BLOOD MONOCYTES
  • TYPE-2
  • SECRETION
  • PROTEIN
  • SIGNAL
  • CELLS
  • BIOSYNTHESIS
  • MACROPHAGES
  • EFFICIENCY
  • UROKINASE

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