Cardiac Overexpression of S100A6 Attenuates Cardiomyocyte Apoptosis and Reduces Infarct Size After Myocardial Ischemia-Reperfusion.
Cardiomyocyte-specific transgenic mice overexpressing S100A6, a member of the family of EF-hand calcium-binding proteins, develop less cardiac hypertrophy, interstitial fibrosis, and myocyte apoptosis after permanent coronary ligation, findings that support S100A6 as a potential therapeutic target after acute myocardial infarction. Our purpose was to investigate S100A6 gene therapy for acute myocardial ischemia-reperfusion.



We first performed in vitro studies to examine the effects of S100A6 overexpression and knockdown in rat neonatal cardiomyocytes. S100A6 overexpression improved calcium transients and protected against apoptosis induced by hypoxia-reoxygenation via enhanced calcineurin activity, whereas knockdown of S100A6 had detrimental effects. For in vivo studies, human S100A6 plasmid or empty plasmid was delivered to the left ventricular myocardium by ultrasound-targeted microbubble destruction in Fischer-344 rats 2 days prior to a 30-minute ligation of the left anterior descending coronary artery followed by reperfusion. Control animals received no therapy. Pretreatment with S100A6 gene therapy yielded a survival advantage compared to empty-plasmid and nontreated controls. S100A6-pretreated animals had reduced infarct size and improved left ventricular systolic function, with less myocyte apoptosis, attenuated cardiac hypertrophy, and less cardiac fibrosis.



S100A6 overexpression by ultrasound-targeted microbubble destruction helps ameliorate myocardial ischemia-reperfusion, resulting in lower mortality and improved left ventricular systolic function post-ischemia-reperfusion via attenuation of apoptosis, reduction in cardiac hypertrophy, and reduced infarct size. Our results indicate that S100A6 is a potential therapeutic target for acute myocardial infarction.
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Azadeh
A
Mofid
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Nadav S
NS
Newman
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Paul J H
PJ
Lee
Department of Physiology, University of Toronto, Ontario, Canada.
Cynthia
C
Abbasi
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Pratiek N
PN
Matkar
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Dmitriy
D
Rudenko
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Michael A
MA
Kuliszewski
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Hao H
HH
Chen
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Kolsoom
K
Afrasiabi
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
James N
JN
Tsoporis
Department of Physiology, University of Toronto, Ontario, Canada.
Anthony O
AO
Gramolini
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Kim A
KA
Connelly
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Thomas G
TG
Parker
Division of Cardiology, Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada leong-poih@smh.ca.
Howard
H
Leong-Poi
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics*; D004195:Disease Models, Animal; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D009203:Myocardial Infarction / Q000209:etiology / Q000235:genetics* / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000150:complications* / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000473:pathology; D012313:RNA / Q000235:genetics*; D051381:Rats; D011916:Rats, Inbred F344; D060888:Real-Time Polymerase Chain Reaction; D000075383:S100 Calcium Binding Protein A6 / Q000096:biosynthesis / Q000235:genetics*; D015398:Signal Transduction
D018797:Cell Cycle Proteins; D000075383:S100 Calcium Binding Protein A6; C489132:S100a6 protein, rat; D012313:RNA
S100A6; apoptosis; gene therapy; hypertrophy; ischemia‐reperfusion; ultrasound‐targeted microbubble destruction