Document Detail


Critical role for classical PKC in activating Akt by phospholipase A2-modified LDL in monocytic cells.
MedLine Citation:
PMID:  17261275     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: Modification of low density lipoprotein (LDL) by phospholipases confers pro-atherogenic properties, although signalling pathways of phospholipase-modified LDL (PLA-LDL) remain obscure. We questioned whether members of the protein kinase C (PKC) family are involved in PLA-LDL-induced Akt phosphorylation and survival of THP-1 monocytic cells. METHODS: Akt phosphorylation in THP-1 cells was monitored by Western analysis. To modulate PKC expression cells were transfected with dominant-negative enhanced green fluorescent protein linked PKCalpha (PKCalpha-EGFP K368R) and PKCbeta (PKCbeta-EGFP K371M) constructs or with siRNA specific for PKCalpha/PKCbeta using nucleofection technology. Cell survival was assessed by Annexin V/propidium iodide staining or mitochondrial membrane potential measurement with 3,3'-dihexyloxacarbocyanine iodide (DiOC(6)) using flow cytometry. RESULTS: Inhibitors of phospholipase C (PLC) or classical PKCs as well as PKC depletion following phorbol ester treatments, blocked Akt phosphorylation in response to PLA-LDL. In contrast, phosphatidylinositol 3-kinase (PI3K) activation by PLA-LDL was insensitive to PKC inhibition. Using RNA interference to knockdown PKCalpha and overexpression of dominant-negative PKCalpha as well as PKCbeta drastically lowered Akt phosphorylation after PLA-LDL. Moreover, inhibition of PKC attenuated a PLA-LDL-induced survival response towards oxidative stress in THP-1 cells. CONCLUSION: We show that PKCalpha and PKCbeta are critical for PLA-LDL-induced Akt phosphorylation and survival in THP-1 monocytic cells.
Authors:
Stefan Preiss; Dmitry Namgaladze; Bernhard Brüne
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-12-30
Journal Detail:
Title:  Cardiovascular research     Volume:  73     ISSN:  0008-6363     ISO Abbreviation:  Cardiovasc. Res.     Publication Date:  2007 Mar 
Date Detail:
Created Date:  2007-02-19     Completed Date:  2007-05-21     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0077427     Medline TA:  Cardiovasc Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  833-40     Citation Subset:  IM    
Affiliation:
Faculty of Medicine, Institute of Biochemistry I, Johann Wolfgang Goethe-University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
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MeSH Terms
Descriptor/Qualifier:
Blotting, Western / methods
Cell Line, Tumor
Green Fluorescent Proteins / genetics
Group IV Phospholipases A2
Humans
Lipoproteins, LDL / metabolism*
Microscopy, Fluorescence
Monocytes / metabolism*
Phospholipases A / metabolism*
Phospholipases A2
Protein Kinase C / genetics,  physiology*
Proto-Oncogene Proteins c-akt / metabolism*
RNA, Small Interfering / pharmacology
Signal Transduction / physiology*
Transfection / methods
Chemical
Reg. No./Substance:
0/Lipoproteins, LDL; 0/RNA, Small Interfering; 0/low density lipoprotein inhibitor; 147336-22-9/Green Fluorescent Proteins; EC 2.7.11.1/Proto-Oncogene Proteins c-akt; EC 2.7.11.13/Protein Kinase C; EC 3.1.1.-/Phospholipases A; EC 3.1.1.4/Group IV Phospholipases A2; EC 3.1.1.4/Phospholipases A2

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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