Yohei Noguchi, Atsushi Okamoto, Takeshi Kasama, Shinobu Imajoh-Ohmi, Takashi Karatsu, Hiroyuki Nogawa
Department of Life and Earth Sciences, Graduate School of Science and Technology, Chiba University, Chiba, Japan.
Developmental dynamics : an official publication of the American Association of Anatomists 2006 FebEpithelial morphogenesis is supported by diffusible growth factors and by nondiffusible cell substrata, such as laminin and fibronectin. When embedded in a laminin-rich basement-membrane substratum, embryonic mouse submandibular epithelium undergoes cell proliferation and branching morphogenesis in response to epidermal growth factor (EGF) in mesenchyme-free culture but not in serum-free medium. In this study, we sought to identify the biologically active factor in serum. As this factor was heat-stable and trypsin-resistant, the lipid fraction was analyzed. Horse serum was fractionated by ethanol extraction, Folch partition with chloroform-methanol-water, and high-performance liquid chromatography, and we tested the branch-inducing activity of each fraction. We also analyzed the partially purified fraction with a mass spectrometer, indicating that the active fraction largely consisted of lysophosphatidyl-hexose. Finally we identified the molecule as lysophosphatidic acid (LPA), because, whereas lysophosphatidyl-inositol had only a slight branch-inducing activity, its relevant LPA fully substituted for serum and induced branching morphogenesis in cooperation with EGF. LPA receptor genes were expressed in submandibular epithelial cells. DNA-synthesizing cells were abundant only when cultured in the presence of both EGF and LPA, but not either singly. Copyright 2005 Wiley-Liss, Inc.
Yohei Noguchi, Atsushi Okamoto, Takeshi Kasama, Shinobu Imajoh-Ohmi, Takashi Karatsu, Hiroyuki Nogawa. Lysophosphatidic acid cooperates with EGF in inducing branching morphogenesis of embryonic mouse salivary epithelium. Developmental dynamics : an official publication of the American Association of Anatomists. 2006 Feb;235(2):403-10
PMID: 16317726
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