Abstract
Interferon regulatory factor-1 (IRF-1) is a candidate transcription factor for the regulation of the Toll-like receptor-4 (TLR-4) gene. Using a small interfering RNA-based (siRNA) process to silence IRF-1 gene expression in the leukemic monocytic cell line THP-1, we investigated whether such a modulation would alter TLR-4 expression and activation status in these cells. The siIRF-1 cells expressed elevated levels of TLR-4 mRNA and protein compared to controls by 90% and 77%, respectively. ICAM.1 protein expression and apoptosis levels were increased by 8.35- and 4.25-fold, respectively. The siIRF-1 cells overexpressed Bax mRNA compared to controls. Proteomic analysis revealed upmodulation of the Annexin-II protein in siIRF-1 THP-1 cells. Myelodysplastic syndrome (MDS) patients with an absence of full-length IRF-1 mRNA also overexpressed Annexin-II. It is plausible that this overexpression may lead to the activation of TLR-4 contributing to the increased apoptosis characterizing MDS.
Keywords:
Annexin II; IRF-1; RNAi; TLR-4; myelodysplastic syndrome.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Amino Acid Sequence
-
Annexin A2 / biosynthesis*
-
Annexin A2 / genetics
-
Apoptosis
-
Bone Marrow Cells / metabolism
-
Bone Marrow Cells / pathology
-
Cells, Cultured / drug effects
-
Cells, Cultured / metabolism
-
Gene Expression Regulation / drug effects
-
Humans
-
Intercellular Adhesion Molecule-1 / biosynthesis
-
Intercellular Adhesion Molecule-1 / genetics
-
Interferon Regulatory Factor-1 / antagonists & inhibitors*
-
Interferon Regulatory Factor-1 / genetics
-
Interferon Regulatory Factor-1 / physiology
-
Leukemia, Promyelocytic, Acute / metabolism
-
Leukemia, Promyelocytic, Acute / pathology
-
Molecular Sequence Data
-
Monocytes / metabolism*
-
Myelodysplastic Syndromes / metabolism
-
Myelodysplastic Syndromes / pathology
-
Protein Structure, Tertiary
-
RNA Interference*
-
RNA, Messenger / genetics
-
RNA, Small Interfering / pharmacology
-
Toll-Like Receptor 4 / biosynthesis*
-
Toll-Like Receptor 4 / genetics
-
Transfection
-
bcl-2-Associated X Protein / biosynthesis
-
bcl-2-Associated X Protein / genetics
Substances
-
ANXA2 protein, human
-
Annexin A2
-
BAX protein, human
-
Interferon Regulatory Factor-1
-
RNA, Messenger
-
RNA, Small Interfering
-
TLR4 protein, human
-
Toll-Like Receptor 4
-
bcl-2-Associated X Protein
-
Intercellular Adhesion Molecule-1