Studies on high molecular weight fibroblast growth factor-2 isoforms produced by rat and human cardiac myofibroblasts
| dc.contributor.author | Santiago, Jon-Jon | |
| dc.contributor.examiningcommittee | Dixon, Ian (Physiology) Zahradka, Peter (Physiology) Netticadan, Thomas (Physiology) Wigle, Jeff (Biochemistry & Medical Genetics) Anand-Srivastava, Madhu (University of Montreal) | en_US |
| dc.contributor.supervisor | Kardami, Elissavet (Physiology) | en_US |
| dc.date.accessioned | 2014-08-25T14:53:56Z | |
| dc.date.available | 2014-08-25T14:53:56Z | |
| dc.date.issued | 2011-08-09 | en_US |
| dc.date.issued | 2014-05-14 | en_US |
| dc.degree.discipline | Physiology | en_US |
| dc.degree.level | Doctor of Philosophy (Ph.D.) | en_US |
| dc.description.abstract | Fibroblast growth factor-2 (FGF-2) is expressed as high molecular weight (> 20 kDa, Hi-FGF-2), or low molecular weight, (18 kDa, Lo-FGF-2) isoforms with distinct functions in the heart and other tissues. Studies to-date have focused on Lo-FGF-2, while the biology of Hi-FGF-2 is less well understood. This work investigated potential autocrine and paracrine effects of rat and human Hi-FGF-2 on cardiac myocytes and non-myocytes (myofibroblasts). Using rat ventricular myofibroblast cultures stimulated with angiotensin II (Ang II), in the absence or presence of YVAD, a peptide inhibitor of caspase-1, it was shown that caspase-1 activity was required for the Ang II-stimulated Hi-FGF-2 secretion. Secreted rat Hi-FGF-2 was shown to be biologically active and capable of stimulating neonatal as well as adult cardiomyocyte hypertrophy in vitro. The effect of extracellular-acting Hi- versus Lo-FGF-2 on the secretome profile of rat cardiac myofibroblasts was compared. Conditioned media collected after stimulation with rat Hi- or Lo-FGF-2 were analyzed by mass spectroscopy (LC-MS/MS). Secretome profiles suggested that Hi-FGF-2 was more potent than Lo-FGF-2 in upregulating several matricellular and fibrosis-associated proteins, most prominently periostin, follistatin-like protein 1, plasminogen activator inhibitor-1, and tenascin. Human heart (atrial) tissue, pericardial fluid, and human heart-derived myofibroblasts were shown to accumulate predominantly Hi-FGF-2. Ang II up-regulated Hi-FGF-2 in human cells, via activation of: type 1 or type 2 Ang II receptors (AT-1R, AT-2R); the ERK pathway; and matrix metalloprotease-2. Neutralizing antibodies specific for Hi-FGF-2 (neu-AbHi-FGF-2) reduced expression of proteins associated with fibroblast-to-myofibroblast conversion and fibrosis. Blocking the autocrine action of Hi-FGF-2 on human cells with neu-AbHi-FGF-2 resulted in down-regulation of periostin, as well as α-smooth muscle actin, pro-collagen, embryonic smooth muscle myosin, and extra domain A fibronectin, consistent with a reversal from activated myofibroblast to fibroblast phenotype. Stimulation of human myofibroblasts with human Hi-FGF-2 was significantly more potent than Lo-FGF-2 in upregulating pro-interleukin-1β and plasminogen activator inhibitor-1, considered to be pro-inflammatory proteins. It is concluded that exported, extracellular-acting Hi-FGF-2 has pro-fibrotic, pro-inflammatory, and pro-hypertrophic properties, contributes to the ‘activated fibroblast’ phenotype, and represents a therapeutic target for prevention of maladaptive cardiac remodeling in humans. | en_US |
| dc.description.note | October 2014 | en_US |
| dc.identifier.citation | Cardiovasc Res. 2011 Jan 1;89(1):139-47. doi: 10.1093/cvr/cvq261. Epub 2010 Aug 9 | en_US |
| dc.identifier.citation | PLoS One. 2014 May 14;9(5):e97281. doi: 10.1371/journal.pone.0097281. eCollection 2014 | en_US |
| dc.identifier.uri | http://hdl.handle.net/1993/23867 | |
| dc.language.iso | eng | en_US |
| dc.publisher | Oxford Journals | en_US |
| dc.publisher | Open Access Scholarly Publishers Association | en_US |
| dc.rights | open access | en_US |
| dc.subject | FGF-2 | en_US |
| dc.subject | hypertrophy | en_US |
| dc.subject | remodeling | en_US |
| dc.subject | fibrosis | en_US |
| dc.subject | inflammation | en_US |
| dc.subject | myofibroblasts | en_US |
| dc.title | Studies on high molecular weight fibroblast growth factor-2 isoforms produced by rat and human cardiac myofibroblasts | en_US |
| dc.type | doctoral thesis | en_US |