3'-untranslated region of SP-B mRNA mediates inhibitory effects of TPA and TNF-alpha on SP-B expression.
Surfactant protein-B (SP-B) is a small hydrophobic polypeptide that enhances spreading and stability of surfactant phospholipids in the alveolus of the lung. Decreased expression of SP-B is associated with respiratory failure in premature infants and in adult patients with acute respiratory distress syndrome (ARDS). Tumor necrosis factor-alpha (TNF-alpha) and 12-O-tetradecanoylphorbol-13 acetate (TPA) cause ARDS-like lung injury in vivo. Inhibitory effects of TPA and TNF-alpha on SP-B mRNA expression in vitro were mediated by decreased SP-B mRNA stability rather than by decreased rate of SP-B gene transcription. In the present study, a human pulmonary adenocarcinoma cell line, NCI H441-4, was stably transfected with expression vectors consisting of the thymidine kinase (TK) promotor and human growth hormone (hGH) gene, in which the hGH 3'-untranslated region (3'-UTR) was replaced by the 2.0-kb human SP-B cDNA [pTKGH(SP-B2.0)] or the 837-bp human SP-B 3'-UTR [pTKGH(SP-B.837)]. The mRNAs and cellular growth hormone protein generated from the chimeric TKGH(SP-B2.0) and TKGH(SP-B.837) genes were each inhibited by approximately 50% by TPA and TNF-alpha. Dexamethasone decreased the inhibitory effects of TPA and TNF-alpha. The inhibition of steady-state hGH-SP-B mRNA by TPA and TNF-alpha was mediated by a cis-active element located in the 3-UTR region of SP-B mRNA.
Pryhuber
G S
GS
Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039.
Church
S L
SL
Kroft
T
T
Panchal
A
A
Whitsett
J A
JA
D001483:Base Sequence; D013006:Growth Hormone / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes / Q000235:genetics; D014176:Protein Biosynthesis; D011510:Proteolipids / Q000235:genetics* / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D015345:Oligonucleotide Probes; D011510:Proteolipids; D011663:Pulmonary Surfactants; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D013006:Growth Hormone; D013755:Tetradecanoylphorbol Acetate