title: Heat shock protein 25-enriched plasma transfusion preconditions the heart against doxorubicin-induced dilated cardiomyopathy in mice.
abstract: Extracellular heat shock proteins (eHsps) in the circulation have recently been found to activate both apoptotic and protective signaling in the heart. However, the role of eHsps in doxorubicin (Dox)-induced heart failure has not yet been studied. The objective of the present study was to determine how Dox affects circulating eHsp25 in blood plasma and how eHsp25 affects Dox-induced dilated cardiomyopathy. Wild-type mice [HSF-1(+/+)] were pretreated with 100 μl of heterozygous heat shock factor-1 [HSF-1(+/-)] mouse plasma (which contained 4-fold higher eHsp25 compared with wild-type mice), HSF-1(+/+) plasma, or saline, before treatment with Dox (6 mg/kg). After 4 weeks of this treatment protocol, HSF-1(+/-) plasma-pretreated mice showed increased eHsp25 in plasma and improved cardiac function (percentage of fractional shortening 37.3 ± 2.1 versus 26.4 ± 4.0) and better life span (31 ± 2 versus 22 ± 3 days) compared with the HSF-1(+/+) plasma or saline-pretreated mice. Preincubation of isolated adult cardiomyocytes with HSF-1(+/-) plasma or recombinant human Hsp27 (rhHsp27) significantly reduced Dox-induced activation of nuclear factor-κB and cytokine release and delayed cardiomyocyte death. Moreover, when cardiomyocytes were incubated with fluorescence-tagged rhHsp27, a saturation in binding was observed, suggesting that eHsp25 can bind to surface receptors. Competitive assays with a Toll-like receptor 2 (TLR2) antibody reduced the rhHSP27 binding, indicating that Hsp25 interacts with TLR2. In conclusion, transfusion of Hsp25-enriched blood plasma protected the heart from Dox-induced cardiotoxicity. Hsp25 antagonized Dox binding to the TLR2 receptor on cardiomyocytes.
authors.affiliation: Division of Cardiovascular Medicine, Davis Heart & Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Karthikeyan
authors.initials: K
authors.lastname: Krishnamurthy
authors.forename: Ragu
authors.initials: R
authors.lastname: Kanagasabai
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Druhan
authors.forename: Govindasamy
authors.initials: G
authors.lastname: Ilangovan
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D001803:Blood Transfusion; D002311:Cardiomyopathy, Dilated / Q000139:chemically induced / Q000517:prevention & control*; D016207:Cytokines / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000097:blood; D004195:Disease Models, Animal; D004317:Doxorubicin / Q000633:toxicity*; D004452:Echocardiography; D019084:Fluorescent Antibody Technique, Indirect; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000097:blood*; D015151:Immunoblotting; D019157:Ischemic Preconditioning, Myocardial; D051379:Mice; D008807:Mice, Inbred BALB C; D018832:Molecular Chaperones; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000502:physiology; D016328:NF-kappa B / Q000378:metabolism; D009363:Neoplasm Proteins / Q000097:blood*; D013997:Time Factors; D051193:Toll-Like Receptors / Q000378:metabolism; D014157:Transcription Factors / Q000097:blood
chemical_list: D000903:Antibiotics, Antineoplastic; D016207:Cytokines; D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; C490017:Hsf1 protein, mouse; D018832:Molecular Chaperones; D016328:NF-kappa B; D009363:Neoplasm Proteins; D051193:Toll-Like Receptors; D014157:Transcription Factors; D004317:Doxorubicin