MicroRNA-21 is a key determinant in IL-11/Stat3 anti-apoptotic signalling pathway in preconditioning of skeletal myoblasts.
OBJECTIVE
We have previously shown that preconditioning of stem and progenitor cells promotes their survival post-engraftment in the infarcted heart. The present study was designed to (i) delineate the role of microRNA-21 (miR-21) in interleukin-11 (IL-11) signalling during preconditioning of skeletal myoblasts (MY) and (ii) study the long-term fate of preconditioned MY ((PC)MY) post-transplantation in the infarcted heart.


RESULTS
We report that pharmacological preconditioning of MY with diazoxide showed robust expression of IL-11 and activation of extracellular signal-regulated kinase 1/2 (Erk1/2) and signal transducers and activators of transcription-3 (Stat3) with concomitantly increased miR-21. These molecular events improved cytoprotection of (PC)MY under oxidant stress in vitro which was compromised by pre-treatment of (PC)MY with IL-11-specific siRNA, Erk1/2 blocker, or anti-miR-21. In vivo studies for sry-gene detection in a female rat heart model of acute myocardial infarction showed two-fold higher survival of male donor (PC)MY 4 and 7 days post-engraftment. Long-term fate of the engrafted cells was determined at 4 months after transplantation. Immunohistological studies revealed that in comparison with (non-PC)MY, (PC)MY improved angiogenic response in the heart which was evident from a higher number of blood vessels per surface area (0.155 mm(2)) and myogenic differentiation of (PC)MY in the heart. Indices of myocardial contractility including ejection fraction and fractional shortening showed significant improvement in (PC)MY-treated animals.


CONCLUSIONS
miR-21 is a key regulator of Erk1/2-Stat3 signalling downstream of IL-11 during preconditioning of MY. The therapeutic benefits of (PC)MY were stable and persisted until 4 months of observation.
Haider
Khawaja Husnain
KH
Department of Pathology, University of Cincinnati, Cincinnati, OH 45267-0529, USA. haiderkh@ucmail.uc.edu
Idris
Niagara Muhammad
NM
Kim
Ha Won
HW
Ahmed
Rafeeq P H
RP
Shujia
Jiang
J
Ashraf
Muhammad
M
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002454:Cell Differentiation; D002470:Cell Survival; D002478:Cells, Cultured; D003981:Diazoxide / Q000494:pharmacology; D004195:Disease Models, Animal; D005260:Female; D017370:Interleukin-11 / Q000378:metabolism*; D008297:Male; D035683:MicroRNAs / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D032448:Myoblasts, Skeletal / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology / Q000637:transplantation; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology / Q000637:transplantation; D018919:Neovascularization, Physiologic; D018384:Oxidative Stress; D034622:RNA Interference; D051381:Rats; D011916:Rats, Inbred F344; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D051876:Sex-Determining Region Y Protein / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D013318:Stroke Volume; D013997:Time Factors; D014162:Transfection
D017370:Interleukin-11; D035683:MicroRNAs; D050796:STAT3 Transcription Factor; D051876:Sex-Determining Region Y Protein; C494088:Stat3 protein, rat; C546082:mirn21 microRNA, rat; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D003981:Diazoxide