TNF-alpha and cortisone impair peptide chain initiation by altering the availability of initiation factor EIF-4E.
The effect of chronic tumor necrosis factor-a (TNF-a) and cortisone treatment on the concentration of translational initiation factor eIF-4E in rat skeletal muscle was evaluated. Crude muscle extracts from control and experimental groups (TNF-a s.c. @ 50 microg/kg body wt each day for 5 days or cortisone s.c. @ 100 mg/kg body wt for 5 days) were used to purify eIF-4E by immunoprecipitation and polyacrylamide gel electrophoresis (PAGE) followed by Western blot analysis. Quantification of eIF-4E was done by densitometry. Both TNF-a and cortisone induced a marked decline in the concentration of eIF-4E in rat skeletal muscle. There was no difference in the ratio of phosphorylated to unphosphorylated eIF-4E after TNF-a treatment. These findings suggest that both TNF-a and cortisone inhibit peptide chain initiation in skeletal muscle cells by decreasing the expression of eIF-4E.
Cheema
Ijaz R
IR
Division of Science and Mathematics, Bethune-Cookman College, Daytona Beach, Florida 32114, USA. cheemai@cookman.edu
Jones
Donald L
DL
D000818:Animals; D015153:Blotting, Western; D003348:Cortisone / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D039561:Eukaryotic Initiation Factor-4E / Q000032:analysis / Q000378:metabolism*; D006614:Hindlimb; D018482:Muscle, Skeletal / Q000737:chemistry / Q000187:drug effects; D010442:Peptide Chain Initiation, Translational / Q000187:drug effects / Q000502:physiology*; D010448:Peptide Initiation Factors; D010766:Phosphorylation / Q000187:drug effects; D011233:Precipitin Tests; D014176:Protein Biosynthesis / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D014020:Tissue Extracts / Q000737:chemistry / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
D039561:Eukaryotic Initiation Factor-4E; D010448:Peptide Initiation Factors; D014020:Tissue Extracts; D014409:Tumor Necrosis Factor-alpha; D003348:Cortisone