A novel set of hepatic mRNAs preferentially expressed during an acute inflammation in rat represents mostly intracellular proteins

A cloning of hepatic cDNAs associated with the early phase of an acute, sys temic inflammation was carried out by differential screening of arrayed cDN A clones from rat livers obtained at 4-8 h postchallenge with Freund's comp lete adjuvant. End sequencing of 174 selected clones provided three cDNA gr oups that coded for: (i) 23 known acute-phase proteins, (ii) 31 known prote ins whose change in hepatic synthesis during an acute phase was so far unsu spected, and (iii) 36 novel proteins whose cDNAs were completely sequenced. For 16 proteins in the third group the hepatic mRNA could be detected and quantitated by Northern blot hybridization in Freund's adjuvant-challenged animals, and an extrahepatic expression in healthy animals was further inve stigated. Matching the open reading frames of the 36 novel proteins with ge neral and specialized data libraries indicated the potential relationships of 16 of these proteins with known protein families/superfamilies and/or th e presence of functional domains previously described in other proteins. Ov erall, our search for novel inflammation-associated proteins selected mostl y known or as yet undescribed proteins with an intracellular or membrane lo cation, which extends our knowledge of the proteins involved in the intrace llular metabolism of hepatic cells during a systemic, acute-phase response. Finally, some of the cDNAs above allowed us to successfully identify hepat ic mRNAs that are differentially expressed in acute vs chronic (polyarthrit is) inflammatory conditions in rat. (C) 1999 Academic Press.