Lu B, Sims PJ, Wiedmer T, Moser AH, Shigenaga JK, Grunfeld C, Feingold KR. Expression of the phospholipid scramblase (PLSCR) gene family during the acute phase response.
Biochim Biophys Acta Mol Cell Biol Lipids 2007;
1771:1177-85. [PMID:
17590392 DOI:
10.1016/j.bbalip.2007.05.002]
[Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 04/27/2007] [Accepted: 05/17/2007] [Indexed: 10/23/2022]
Abstract
Phospholipid scramblase 1 (PLSCR1) is a member of PLSCR gene family that has been implicated in multiple cellular processes including movement of phospholipids, gene regulation, immuno-activation, and cell proliferation/apoptosis. In the present study, we identified PLSCR1 as a positive intracellular acute phase protein that is upregulated by LPS in liver, heart, and adipose tissue, but not skeletal muscle. LPS administration resulted in a marked increase in PLSCR1 mRNA and protein levels in the liver. This stimulation occurred rapidly (within 2 h), and was very sensitive to LPS (half-maximal response at 0.1 microg/mouse). Moreover, two other APR-inducers, zymosan and turpentine, also produced significant increases in PLSCR1 mRNA and protein levels, indicating that PLSCR1 was stimulated in a number of models of the APR. To determine signaling pathways by which LPS stimulated PLSCR1, we examined the effect of proinflammatory cytokines in vitro and in vivo. TNFalpha, IL-1beta, and IL-6 all stimulated PLSCR1 in cultured Hep B3 hepatocytes, whereas only TNFalpha stimulated PLSCR1 in cultured 3T3-L1 adipocytes, suggesting cell type-specific effects of cytokines. Furthermore, the LPS-stimulated increase in liver PLSCR1 mRNA was greatly attenuated by 80% in TNFalpha and IL-1beta receptor null mice as compared to wild-type controls. In contrast, PLSCR1 levels in adipose tissue were induced to a similar extent in TNFalpha and IL-1beta receptor null mice and controls. These results indicate that maximal stimulation of PLSCR1 by LPS in liver required TNFalpha and/or IL-1beta, whereas the stimulation of PLSCR1 in adipose tissue is not dependent on TNFalpha and/or IL-1beta. These data provide evidence that PLSCR1 is a positive intracellular acute phase protein with a tissue-specific mechanism for up-regulation.
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