Inhibition of the ubiquitin-proteasome pathway induces differential heat-shock protein response in cardiomyocytes and renders early cardiac protection.
The effects of proteasome inhibition (PI) on heat-shock protein (HSP) expression in cardiomyocytes were investigated. Neonatal rat cardiomyocytes were incubated with MG132 (0.1-10 microM) for 1 h. Induction of various HSPs was determined by real-time PCR and Western blotting. PI induced a 2- to 3-fold increase in HSP27, HSP60, and HSP90, and a 18-fold increase in HSP70 mRNA expression, whereas HSP40 levels were unaffected. Western blotting revealed increased protein expression for HSP70 after PI. Similar results were obtained with MG262. HSP induction correlated with enhanced survival of neonatal cardiomyocytes after sublethal heat stress in XTT testing. In papillary muscles, pretreatment with MG132 (10 microM, 90 min) was associated with enhanced recovery of the contractile parameters after a 40-min hypoxia. In these proof-of-principle experiments, we show that PI induces differential heat-shock response in cardiomyocytes, accompanied by enhanced cell survival and functional recovery after various forms of stress.
Stangl
Karl
K
Medizinische Klinik mit Schwerpunkt Kardiologie, Angiologie, und Pneumologie, Institute of Biochemistry, Charité, Campus Mitte, Humboldt-Universität zu Berlin, Schumannstrasse 20-21, Berlin, D-10117, Germany. karl.stangl@charite.de
Günther
Christoph
C
Frank
Thomas
T
Lorenz
Mario
M
Meiners
Silke
S
Röpke
Thorsten
T
Stelter
Lars
L
Moobed
Minoo
M
Baumann
Gert
G
Kloetzel
Peter-Michael
PM
Stangl
Verena
V
D000828:Animal Population Groups; D000818:Animals; D000831:Animals, Newborn; D002316:Cardiotonic Agents / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D046508:Culture Techniques; D003546:Cysteine Endopeptidases; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D018869:Heat-Shock Response; D007700:Kinetics; D007976:Leupeptins / Q000494:pharmacology*; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors*; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D010210:Papillary Muscles / Q000187:drug effects / Q000502:physiology; D046988:Proteasome Endopeptidase Complex; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D025801:Ubiquitin / Q000037:antagonists & inhibitors*
D002316:Cardiotonic Agents; D015853:Cysteine Proteinase Inhibitors; D006360:Heat-Shock Proteins; D007976:Leupeptins; D009097:Multienzyme Complexes; D012333:RNA, Messenger; D025801:Ubiquitin; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde