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Transforming growth factor‐α expression in peritoneal macrophages elicited from SENCAR and B6C3F1 mice: Responses to lipopolysaccharide and 12‐ O ‐tetradecanoylphorbol‐13‐acetate
Author(s) -
Pfeifer Richard W.,
Adams Lorrie A.
Publication year - 1994
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.2940100305
Subject(s) - lipopolysaccharide , in vivo , secretion , phorbol , 12 o tetradecanoylphorbol 13 acetate , in vitro , microbiology and biotechnology , tetradecanoylphorbol acetate , transforming growth factor , chemistry , ratón , biology , medicine , endocrinology , biochemistry , enzyme , protein kinase c , phorbol ester
Recent findings in our laboratory indicated that peritoneal macrophages (MPs) elicited from phorbol ester‐sensitive SENCAR mice generated significant amounts of superoxide when stimulated by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) in vitro; negligible responses were observed for MPs derived from relatively resistant B6C3F1 mice. We hypothesized a similar strain‐dependent secretion of transforming growth factor‐α (TGF‐α) by TPA‐stimulated MPs. TGF‐α secreted by MPs was quantitated by competitive enzyme‐linked immunosorbent assay. After 72 h (maximal secretion), for MPs derived from B6C3F1 mice, in vitro exposure to 10 μg/mL lipopolysaccharide (LPS; non‐lipid‐A‐detoxified) resulted in maximal induction (708 pg/mL), in vivo exposure to intraperitoneally (i.p.) administered TPA (2 μg/mouse) alone resulted in a minimal response (32 pg/mL), and prior in vivo exposure to TPA significantly inhibited (more than 90% suppression) the LPS‐stimulated MP response in culture (i.e., to 62 pg/mL). Although significant amounts of TGF‐α could be detected in both SENCAR‐and B6C3F1‐derived MPs (i.e., approximately 2–3 ng/5x10 6 cells), SENCAR MPs did not secrete TGF‐α in response to either TPA or LPS. In addition, the use of the semiquantitative reverse transcription‐polymerase chain reaction to detect TGF‐a‐specific mRNA did not support the strain dependency observed for LPS‐stimulated TGF‐α secretion, i.e., detectable transcripts were observed in MP RNA derived from both strains. In conclusion, although TPA itself demonstrated negligible effects on TGF‐α expression in murine MPs, prior in vivo exposure inhibited LPS‐stimulated transcriptional activation and intracellular TGF‐α production. The negligible TGF‐α secretion determined for LPS‐stimulated SENCAR‐derived MPs suggested the possibility of a strain‐specific defect in the posttranslational processing of the proTGF‐α molecule. © 1994 Wiley‐Liss, Inc.