Gene expression and biological processes influenced by deletion of Stat3 in pulmonary type II epithelial cells.
BACKGROUND
The signal transducer and activator of transcription 3 (STAT3) mediates gene expression in response to numerous growth factors and cytokines, playing an important role in many cellular processes. To better understand the molecular mechanisms by which Stat3 influences gene expression in the lung, the effect of pulmonary epithelial cell specific deletion of Stat3 on genome wide mRNA expression profiling was assessed. Differentially expressed genes were identified from Affymetrix Murine GeneChips analysis and subjected to gene ontology classification, promoter analysis, pathway mapping and literature mining.


RESULTS
Total of 791 mRNAs were significantly increased and 314 mRNAs were decreased in response to the deletion of Stat3Delta/Delta in the lung. STAT is the most enriched cis-elements in the promoter regions of those differentially expressed genes. Deletion of Stat3 induced genes influencing protein metabolism, transport, chemotaxis and apoptosis and decreased the expression of genes mediating lipid synthesis and metabolism. Expression of Srebf1 and 2, genes encoding key regulators of fatty acid and steroid biosynthesis, was decreased in type II cells from the Stat3Delta/Delta mice, consistent with the observation that lung surfactant phospholipids content was decreased. Stat3 influenced both pro- and anti-apoptotic pathways that determine cell death or survival. Akt, a potential transcriptional target of Stat3, was identified as an important participant in Stat3 mediated pathways including Jak-Stat signaling, apoptosis, Mapk signaling, cholesterol and fatty acid biosynthesis.


CONCLUSIONS
Deletion of Stat3 from type II epithelial cells altered the expression of genes regulating diverse cellular processes, including cell growth, apoptosis and lipid metabolism. Pathway analysis indicates that STAT3 regulates cellular homeostasis through a complex regulatory network that likely enhances alveolar epithelial cell survival and surfactant/lipid synthesis, necessary for the protection of the lung during injury.
Xu
Yan
Y
Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH, USA. yan.xu@cchmc.org
Ikegami
Machiko
M
Wang
Yanhua
Y
Matsuzaki
Yohei
Y
Whitsett
Jeffrey A
JA
D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D002478:Cells, Cultured; D002784:Cholesterol / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D004847:Epithelial Cells / Q000378:metabolism*; D005227:Fatty Acids / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation; D051379:Mice; D008822:Mice, Transgenic; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D011650:Pulmonary Alveoli / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020545:Respiratory Mucosa / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000172:deficiency* / Q000378:metabolism*; D017384:Sequence Deletion / Q000235:genetics*; D015398:Signal Transduction; D014158:Transcription, Genetic; D015854:Up-Regulation
D005227:Fatty Acids; D011663:Pulmonary Surfactants; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; D002784:Cholesterol