1.Synergistic regulation of the acute phase protein SIP24/24p3 by glucocorticoid and pro-inflammatory cytokines.
Quan-Sheng LIU ; Marit NILSEN-HAMILTON ; Si-Dong XIONG
Acta Physiologica Sinica 2003;55(5):525-529
SIP24/24p3 is a secreted murine acute phase protein which has been speculated to play an anti-inflammatory role in vivo. Recently SIP24/24p3 has been found to be able to specifically induce apoptosis in leukocytes. By using (35)S metabolic labeling method, we studied the regulation of SIP24/24p3 by glucocorticoid and pro-inflammatory cytokines IL-6 and TNF-alpha in cultured Balb/c 3T3 and BNL cells. The following results were observed: (1) dexamethasone induced the expression of SIP24/24p3 in both Balb/c 3T3 and BNL cells, the induction was more significant in BNL cells; (2) dexamethasone and IL-6 synergistically induced the expression of SIP24/24p3 in both Balb/c 3T3 and BNL cells; (3) in Balb/c 3T3 cells dexamethasone and TNF-alpha acted synergistically to induce the expression of SIP24/24p3, whereas in BNL cells dexamethasone and TNF-alpha induced the expression of SIP24/24p3 in an additive manner; (4) dexamethasone and IL-6/TNF-alpha acted synergistically in Balb/c 3T3 cells and additively in BNL cells to induce the expression of SIP24/24p3. The inducibility of SIP24/24p3 by multiple factors will help to explain its highly specific expression in vivo. The difference in the expression patterns of SIP24/24p3 in different cell types is also suggestive to its expression and regulation in hepatic and extrahepatic tissues. Finally, the fact that SIP24/24p3 protein can be induced by both pro-inflammatory as well as anti-inflammatory factors is indicative of the important role of SIP24/24p3 in the entire acute phase response process.
Acute-Phase Proteins
;
biosynthesis
;
genetics
;
Animals
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BALB 3T3 Cells
;
Carrier Proteins
;
biosynthesis
;
genetics
;
Cytokines
;
pharmacology
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Dexamethasone
;
pharmacology
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Drug Synergism
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Gene Expression Regulation
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Interleukin-6
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pharmacology
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Lipocalin-2
;
Lipocalins
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Mice
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Mice, Inbred BALB C
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Oncogene Proteins
;
biosynthesis
;
genetics
;
RNA, Messenger
;
biosynthesis
;
genetics
;
Tumor Necrosis Factor-alpha
;
pharmacology