Anti-remodeling and anti-fibrotic effects of the neuregulin-1β glial growth factor 2 in a large animal model of heart failure.

Abstract

BACKGROUND:

Neuregulin-1β (NRG-1β) is a growth factor critical for cardiac development and repair with therapeutic potential for heart failure. We previously showed that the glial growth factor 2 (GGF2) isoform of NRG-1β improves cardiac function in rodents after myocardial infarction (MI), but its efficacy in a large animal model of cardiac injury has not been examined. We therefore sought to examine the effects of GGF2 on ventricular remodeling, cardiac function, and global transcription in post-MI swine, as well as potential mechanisms for anti-remodeling effects.

METHODS AND RESULTS:

MI was induced in anesthetized swine (n=23) by intracoronary balloon occlusion. At 1 week post-MI, survivors (n=13) received GGF2 treatment (intravenous, biweekly for 4 weeks; n=8) or were untreated (n=5). At 5 weeks post-MI, fractional shortening was higher (32.8% versus 25.3%, P=0.019), and left ventricular (LV) end-diastolic dimension lower (4.5 versus 5.3 cm, P=0.003) in GGF2-treated animals. Treatment altered expression of 528 genes, as measured by microarrays, including collagens, basal lamina components, and matricellular proteins. GGF2-treated pigs exhibited improvements in LV cardiomyocyte mitochondria and intercalated disk structures and showed less fibrosis, altered matrix structure, and fewer myofibroblasts (myoFbs), based on trichrome staining, electron microscopy, and immunostaining. In vitro experiments with isolated murine and rat cardiac fibroblasts demonstrate that NRG-1β reduces myoFbs, and suppresses TGFβ-induced phospho-SMAD3 as well as αSMA expression.

CONCLUSIONS:

These results suggest that GGF2/NRG-1β prevents adverse remodeling after injury in part via anti-fibrotic effects in the heart.

• Authors: Cristi L Galindo, Ehab Kasasbeh, Abigail Murphy, Sergey Ryzhov, Sean Lenihan, Farhaan A Ahmad, Philip Williams, Amy Nunnally, Jamie Adcock, Yanna Song, Frank E Harrell, Truc-Linh Tran, Tom J Parry, Jen Iaci, Anindita Ganguly, Igor Feoktistov, Matthew K Stephenson, Anthony O Caggiano, Douglas B Sawyer, John H Cleator
• Journal: Journal of the American Heart Association (J Am Heart Assoc) Vol. 3 Issue 5 Pg. e000773 (Oct 23 2014) ISSN: 2047-9980 [Electronic] England
• PMID: 25341890 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: © 2014 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Chemical References

• Actins
• Neuregulin-1
• Smad3 Protein

Topics

• Actins (metabolism)
• Animals
• Cells, Cultured
• Disease Models, Animal
• Dose-Response Relationship, Drug
• Fibrosis
• Gene Expression Regulation (drug effects)
• Heart Failure (drug therapy, genetics, metabolism, pathology, physiopathology)
• Male
• Mice, Inbred C57BL
• Myocardial Contraction (drug effects)
• Myocardium (metabolism, pathology)
• Myofibroblasts (drug effects, metabolism, pathology)
• Neuregulin-1 (pharmacology)
• Phosphorylation
• Rats, Sprague-Dawley
• Smad3 Protein (metabolism)
• Swine
• Time Factors
• Transcription, Genetic (drug effects)
• Ventricular Function, Left (drug effects)
• Ventricular Remodeling (drug effects, genetics)