Effect of pentamidine on cytokine (IL-1 beta, TNF alpha, IL-6) production by human alveolar macrophages in vitro.
Pentamidine (Pe) is an aromatic diamidine drug used clinically to treat Pneumocystis carinii pneumonia by aerosol inhalation. Nothing has been reported about the effects of this drug on human alveolar macrophage (AM) properties. In this study AM were exposed in vitro to various concentrations of Pe (10(-4)-10(-6) M) alone or in combination with bacterial endotoxin (LPS). Supernatants were collected at 3, 6, and 24 h and assayed for secreted IL-1 beta, IL-6, and TNF alpha. While the drug did not induce release of these cytokines, LPS-induced secretion of all three cytokines was inhibited by Pe in a dose-dependent manner. At the most effective Pe dose, 10(-5) M, AM viability (as determined by trypan blue dye exclusion) was reduced by 14% at 24 h, while no effect on viability was seen at lower concentrations. mRNA expression of all three cytokines was examined by PCR and Northern analysis to establish if the decrease in cytokine secretion was determined on a pre- or post-translational level. Reduced steady-state mRNA levels were found as early as 3 h after LPS stimulation, with Pe concentrations corresponding to those that decreased cytokine secretion. At the later time points, Pe also inhibited beta-actin, ornithine decarboxylase, and GAPDH mRNA expression, indicating that pentamidine had a general toxic effect on mRNA transcription in the macrophages. It is concluded that Pe, at pharmaceutically relevant concentrations and with apparent low cytotoxicity as determined by dye uptake, nonspecifically inhibits cytokine production by a toxic effect on transcriptional events.
Quay
J
J
TRC Environmental Corporation, Chapel Hill, NC 27514.
Rosenthal
G
G
Becker
S
S
D001483:Base Sequence; D015152:Blotting, Northern; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000235:genetics; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis*; D015850:Interleukin-6 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology; D016676:Macrophages, Alveolar / Q000378:metabolism*; D015335:Molecular Probes / Q000235:genetics; D008969:Molecular Sequence Data; D010419:Pentamidine / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D015335:Molecular Probes; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D010419:Pentamidine