Identification of genes differentially expressed in rat alveolar type I cells

Am J Respir Cell Mol Biol. 2004 Sep;31(3):309-16. doi: 10.1165/rcmb.2003-0423OC. Epub 2004 Jun 17.


Although approximately 98% of the internal surface area of the lung is lined by alveolar type I cells, little is known about the functions of this cell type. Using freshly isolated rat type I and type II cells, we created a subtraction library by suppression subtractive hybridization to identify genes differentially expressed by type I cells. We identified twelve genes of known function that are differentially expressed by type I cells. Differential expression of all 12 genes was confirmed by Northern blotting; we confirmed differential expression by immunocytochemistry for 3 genes for which suitable antibodies were available. Most of the genes code for proteins that are multifunctional. From the known functions of these genes, we infer that type I cells may play a role in the maintenance of normal alveolar homeostasis and protection from injury, lung development and remodeling, host defense, tumor/growth suppression, and surfactant metabolism, among other functions.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Caveolin 1
  • Caveolins / genetics
  • Endothelial Cells / cytology
  • Endothelial Cells / metabolism*
  • Gene Expression Profiling
  • Gene Expression Regulation / genetics
  • Membrane Glycoproteins / genetics
  • Membrane Proteins / genetics
  • Nerve Tissue Proteins / genetics
  • Pulmonary Alveoli / cytology
  • Pulmonary Alveoli / metabolism*
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • Rats
  • Rats, Sprague-Dawley
  • Tissue Inhibitor of Metalloproteinase-3 / genetics


  • Caveolin 1
  • Caveolins
  • Membrane Glycoproteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • RNA, Messenger
  • Tissue Inhibitor of Metalloproteinase-3