<P>In a first step to understand the mechanisms for the SCGB3A2's anti-inflammatory and growth factor activities, and how SCGB3A1 and SCGB3A2 expression relate to each other, we analyzed promoter activity of the mouse SCGB3A1 and SCGB3A2 genes using various techniques such as transient transfection analysis, gel mobility shift analysis, chromatin immunoprecipitation, reverse transcriptase-polymerase chain reaction (RT-PCR), quantitative RT-PCR, and the RNAi technique.</P> <P>We found that mouse SCGB3A2 gene expression is regulated by a transcription factor CAATT/enhancer-binding proteins (C/EBP) alpha and delta in synergistic interaction with the homeodomain transcription factor NKX2-1. Simultaneous expression of the three transcription factors allows their synergistic interaction to activate mouse SCGB3A2 gene transcription in lung. On the other hand, the mouse SCGB3A1 gene is regulated by a ubiquitous transcription factor NF-Y, and the lung-specific expression of SCGB3A1 is associated with DNA methylation of the promoter. Thus, methylation of the SCGB3A1 gene promoter appears to play a role in tumor and/or tissue-specific expression.</P><P>In order to determine whether C/EBPs are indeed critical for the <I>in vivo</I> expression of SCGB3A2 in lung, we used doxycycline-inducible lung-specific A-C/EBP mice, which express a dominant negative form of C/EBP (A-C/EBP) in lung only when mice are fed doxycycline. A-C/EBP heterodimerizes with all three C/EBPs (alpha, beta, and delta) and interferes their bindings to DNA, thus inhibiting activities of all three C/EBPs. The use of A-C/EBP is critical to understand the role of C/EBP in the expression of SCGB3A2 in lung because all three C/EBPs are expressed in lung and a lack of one form may be supplemented by the others.</P><P>After doxycycline diet for 4 months, A-C/EBP carrying mice expressed high levels of A-C/EBP, while the level of SCGB3A2 expression was reduced in relative to control as expected from the <I>in vitro</I>studies. Interestingly, the expression of the prototypical member of the SCGB gene superfamily, SCGB1A1, was not reduced in A-C/EBP mice as compared to control even though the previously published <I>in vitro</I>studies demonstrated the importance of C/EBPs in SCGB1A1 gene regulation. We found that this was due to increased expression of the transcription factor FOXA1 both at the mRNA and protein levels. In the presence of C/EBP, FOXA1 only weakly affected SCGB1A1 transcription. These results suggested the importance of <I>in vivo</I>study to understand the <I>in vivo</I>role of transcription factor in the expression of genes of interest.</P><P>In order to demonstrate whether SCGB3A2 plays any additional role in lung physiology and/or diseases, we induced lung fibrosis by direct administration of bleomycin (BLM) or PBS as control into mice lungs by intratracheal intubation. After 2 weeks of BLM treatment, at which time fibrotic foci were barely found in their lungs when subjected to histological analysis, the mice were administered daily intravenous injections of recombinant (rm) SCGB3A2 or PBS through the tail vein for one week. At 3 weeks following BLM treatment, fibrosis was observed in a group of mice administered BLM, while almost all mice that received BLM and rmSCGB3A2, or those received PBS did not develop any fibrosis. Increase of collagen fibers as detected by Masson trichrome staining and the increased numbers of macrophages and neutrophils were noted, suggesting that SCGB3A2 may have an anti-fibrotic activity. Lungs of these mice have been subjected to microarray analyses to understand the mechanism of SCGB3A2 action. The <I>in vitro</I>studies using TGFbeta-induced transformation of fibroblasts to myofibroblasts are also used to understand the SCGB3A2 signaling pathway.</P>

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
1ZIABC010449-07
Application #
7965326
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
7
Fiscal Year
2009
Total Cost
$404,520
Indirect Cost
Name
National Cancer Institute Division of Basic Sciences
Department
Type
DUNS #
City
State
Country
Zip Code
Kim, Jung-Hwan; Yamaori, Satoshi; Tanabe, Tomotaka et al. (2017) Lack of epithelial PPAR? causes cystic adenomatoid malformations in mouse fetal lung. Biochem Biophys Res Commun 491:271-276
Tanaka, Naoki; Aoyama, Toshifumi; Kimura, Shioko et al. (2017) Targeting nuclear receptors for the treatment of fatty liver disease. Pharmacol Ther :
Yoneda, Mitsuhiro; Xu, Lei; Kajiyama, Hiroaki et al. (2016) Secretoglobin Superfamily Protein SCGB3A2 Alleviates House Dust Mite-Induced Allergic Airway Inflammation in Mice. Int Arch Allergy Immunol 171:36-44
Naizhen, Xu; Linnoila, R Ilona; Kimura, Shioko (2016) Co-expression of Achaete-Scute Homologue-1 and Calcitonin Gene-Related Peptide during NNK-Induced Pulmonary Neuroendocrine Hyperplasia and Carcinogenesis in Hamsters. J Cancer 7:2124-2131
Xu, Ming-Jiang; Cai, Yan; Wang, Hua et al. (2015) Fat-Specific Protein 27/CIDEC Promotes Development of Alcoholic Steatohepatitis in Mice and Humans. Gastroenterology 149:1030-41.e6
Yoneda, Mitsuhiro; Molinolo, Alfredo A; Ward, Jerrold M et al. (2015) A Simple Device to Rapidly Prepare Whole Mounts of the Mouse Intestine. J Vis Exp :e53042
Cai, Yan; Kimura, Shioko (2015) Secretoglobin 3A2 Exhibits Anti-Fibrotic Activity in Bleomycin-Induced Pulmonary Fibrosis Model Mice. PLoS One 10:e0142497
Kurotani, Reiko; Shima, Reika; Miyano, Yuki et al. (2015) SCGB3A2 Inhibits Acrolein-Induced Apoptosis through Decreased p53 Phosphorylation. Acta Histochem Cytochem 48:61-8
Cai, Yan; Yoneda, Mitsuhiro; Tomita, Takeshi et al. (2015) Transgenically-expressed secretoglobin 3A2 accelerates resolution of bleomycin-induced pulmonary fibrosis in mice. BMC Pulm Med 15:72
Cheng, Jie; Fang, Zhong-Ze; Nagaoka, Kenjiro et al. (2014) Activation of intestinal human pregnane X receptor protects against azoxymethane/dextran sulfate sodium-induced colon cancer. J Pharmacol Exp Ther 351:559-67

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