IL-6 plays a critical role in the synergistic induction of human serum amyloid A (SAA) gene when stimulated with proinflammatory cytokines as analyzed with an SAA isoform real-time quantitative RT-PCR assay system

Keisuke Hagihara; Teppei Nishikawa; Tomoyasu Isobe; Jian Song; Yasuhiro Sugamata; Kazuyuki Yoshizaki

doi:10.1016/j.bbrc.2003.12.096

IL-6 plays a critical role in the synergistic induction of human serum amyloid A (SAA) gene when stimulated with proinflammatory cytokines as analyzed with an SAA isoform real-time quantitative RT-PCR assay system

Biochem Biophys Res Commun. 2004 Feb 6;314(2):363-9. doi: 10.1016/j.bbrc.2003.12.096.

Authors

Keisuke Hagihara¹, Teppei Nishikawa, Tomoyasu Isobe, Jian Song, Yasuhiro Sugamata, Kazuyuki Yoshizaki

Affiliation

¹ Department of Medical Science I, School of Health and Sport Sciences, Osaka University, Osaka, Japan.

PMID: 14733913
DOI: 10.1016/j.bbrc.2003.12.096

Abstract

Serum amyloid A (SAA) is known to be a precursor of amyloid A (AA) protein in AA (secondary) amyloidosis and SAA1 to be mainly involved in AA amyloidosis. We established an SAA isoform real-time quantitative RT-PCR assay and found that beta-2 microglobulin is more stable as an internal control than GAPDH and beta-actin for our system. Either IL-6 and IL-1beta or IL-6 and TNFalpha, but not IL-1beta and TNFalpha, induced the synergistic induction of SAA1 and SAA2 genes. Anti-IL-6 receptor monoclonal antibody completely inhibited the synergistic induction of SAA1 and SAA2 during triple stimulation with IL-6, IL-1beta, and TNFalpha, but, IL-1 receptor antagonist or anti-TNFalpha monoclonal antibody was only partially inhibited in HepG2, Hep3B, and PLC/PRF/5 cells. Although the SAA1 promoter has no STAT3 consensus sequence, the JAK2 inhibitor-AG490 reduced SAA1 gene expression to 30%, suggesting the involvement of STAT3. We were able to demonstrate that IL-6 plays a critical role in the synergistic induction of human SAA gene when stimulated with proinflammatory cytokines.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Actins / metabolism
Amyloid / chemistry
Antibodies, Monoclonal / chemistry
Antibodies, Monoclonal / metabolism
Blotting, Western
Cell Line
Cell Line, Tumor
Cytokines / biosynthesis*
DNA-Binding Proteins / metabolism
Dose-Response Relationship, Drug
Humans
Interleukin-1 / metabolism
Interleukin-6 / metabolism
Interleukin-6 / physiology*
Promoter Regions, Genetic
Protein Isoforms
RNA, Messenger / metabolism
Reverse Transcriptase Polymerase Chain Reaction
STAT3 Transcription Factor
Serum Amyloid A Protein / chemistry
Serum Amyloid A Protein / genetics*
Time Factors
Trans-Activators / metabolism
Tumor Necrosis Factor-alpha / metabolism
Tyrphostins / pharmacology
beta 2-Microglobulin / metabolism

Substances

Actins
Amyloid
Antibodies, Monoclonal
Cytokines
DNA-Binding Proteins
Interleukin-1
Interleukin-6
Protein Isoforms
RNA, Messenger
STAT3 Transcription Factor
STAT3 protein, human
Serum Amyloid A Protein
Trans-Activators
Tumor Necrosis Factor-alpha
Tyrphostins
alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide
beta 2-Microglobulin