TY - JOUR
T1 - Proteasome inhibition improves diaphragm function in congestive heart failure rats
AU - Van Hees, Hieronymus W.H.
AU - Li, Yi Ping
AU - Ottenheijm, Coen A.C.
AU - Jin, Bingwen
AU - Pigmans, Cindy J.C.
AU - Linkels, Marianne
AU - Dekhuijzen, P. N.Richard
AU - Heunks, Leo M.A.
PY - 2008/6
Y1 - 2008/6
N2 - In congestive heart failure (CHF), diaphragm weakness is known to occur and is associated with myosin loss and activation of the ubiquitin-proteasome pathway. The effect of modulating proteasome activity on myosin loss and diaphragm function is unknown. The present study investigated the effect of in vivo proteasome inhibition on myosin loss and diaphragm function in CHF rats. Coronary artery ligation was used as an animal model for CHF. Sham-operated rats served as controls. Animals were treated with the proteasome inhibitor bortezomib (intravenously) or received saline (0.9%) injections. Force generating capacity, cross-bridge cycling kinetics, and myosin content were measured in diaphragm single fibers. Proteasome activity, caspase-3 activity, and MuRF-1 and MAFbx mRNA levels were determined in diaphragm homogenates. Proteasome activities in the diaphragm were significantly reduced by bortezomib. Bortezomib treatment significantly improved diaphragm single fiber force generating capacity (∼30-40%) and cross-bridge cycling kinetics (∼20%) in CHF. Myosin content was ∼30% higher in diaphragm fibers from bortezomib-treated CHF rats than saline. Caspase-3 activity was decreased in diaphragm homogenates from bortezomib-treated rats. CHF increased MuRF-1 and MAFbx mRNA expression in the diaphragm, and bortezomib treatment diminished this rise. The present study demonstrates that treatment with a clinically used proteasome inhibitor improves diaphragm function by restoring myosin content in CHF.
AB - In congestive heart failure (CHF), diaphragm weakness is known to occur and is associated with myosin loss and activation of the ubiquitin-proteasome pathway. The effect of modulating proteasome activity on myosin loss and diaphragm function is unknown. The present study investigated the effect of in vivo proteasome inhibition on myosin loss and diaphragm function in CHF rats. Coronary artery ligation was used as an animal model for CHF. Sham-operated rats served as controls. Animals were treated with the proteasome inhibitor bortezomib (intravenously) or received saline (0.9%) injections. Force generating capacity, cross-bridge cycling kinetics, and myosin content were measured in diaphragm single fibers. Proteasome activity, caspase-3 activity, and MuRF-1 and MAFbx mRNA levels were determined in diaphragm homogenates. Proteasome activities in the diaphragm were significantly reduced by bortezomib. Bortezomib treatment significantly improved diaphragm single fiber force generating capacity (∼30-40%) and cross-bridge cycling kinetics (∼20%) in CHF. Myosin content was ∼30% higher in diaphragm fibers from bortezomib-treated CHF rats than saline. Caspase-3 activity was decreased in diaphragm homogenates from bortezomib-treated rats. CHF increased MuRF-1 and MAFbx mRNA expression in the diaphragm, and bortezomib treatment diminished this rise. The present study demonstrates that treatment with a clinically used proteasome inhibitor improves diaphragm function by restoring myosin content in CHF.
KW - Bortezomib
KW - Myosin
KW - Single fiber contractility
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U2 - 10.1152/ajplung.00035.2008
DO - 10.1152/ajplung.00035.2008
M3 - Article
C2 - 18424622
AN - SCOPUS:48949119350
SN - 1040-0605
VL - 294
SP - L1260-L1268
JO - American Journal of Physiology - Lung Cellular and Molecular Physiology
JF - American Journal of Physiology - Lung Cellular and Molecular Physiology
IS - 6
ER -