Highlighted ArticleAnalysis of angiogenesis induced by local IGF-1 expression after myocardial infarction using microSPECT-CT imaging
Introduction
Insulin-like growth factor-1 (IGF-1) is a 7.6 kDa polypeptide growth factor, which is expressed by many cells and tissues during embryonic and postnatal development and in adult animals [[1], [2], [3]]. IGF-1 influences various biological processes through binding to a membrane-anchored receptor (IGF-1R), although at higher concentrations, IGF-1 can also activate the insulin receptor [2]. In addition, in vivo, IGF-1 action is modulated by a family of IGF-binding proteins present in the circulation [3]. IGF-1, secreted from the liver in response to growth hormone (GH), promotes postnatal growth in bone, muscle, fat, and other tissues [[1], [2], [3]]. Human and murine IGF-1 deficiency causes severe intrauterine and postnatal growth retardation, perinatal lethality, delayed development in a variety of organs [1], indicating that IGF-1 is a key regulator of cell development. It has recently been reported that overexpression of IGF-1 attenuates myocyte necrosis and apoptosis after infarction in transgenic mouse model [4] and rescues cardiac myocytes from apoptosis in dilated cardiomyopathy [5]. It has also been reported that overexpression of IGF-1 improves cardiomyocyte senescence in transgenic mouse model [6] and reduces cardiomyocyte atrophy induced by ischemia [7]. Accordingly, IGF-1 has been regarded as a pleiotropic growth factor affecting myocyte proliferation and regeneration in heart development and injury.
Recent reports have further indicated that IGF-1 has a strong effect on angiogenesis [[8], [9], [10]], which represents the formation of neovasculature from the endothelium of preexisting vessels. It has been reported that IGF-1 can induce angiogenesis in skeletal muscle and brain tissue [9,10]. Su et al. [8] demonstrated that IGF-1 potently induced endothelial cell migration in a Matrigel assay and capillary formation in organ ring culture assay, which are known as important components of the angiogenic response. As systemic IGF-1 peptide administration induces unfavorable side effects such as edema and tachycardia [11], Rabinovsky et al. performed local injection of expression plasmids containing the IGF-1 gene into the skeletal muscle following femoral artery ligation in mice and demonstrated that IGF-1 treatment evoked angiogenesis and increased blood flow in the skeletal muscle. Therefore, it is plausible that local IGF-1 expression would protect cardiomyocytes from ischemia through induction of angiogenesis under conditions of ischemic injury.
Recombinant adeno-associated virus (AAV) is currently recognized as an effective gene transfer vector for heart diseases [[12], [13], [14]]. The physical stability of AAV makes these vectors advantageous for in vivo use, and transgene expression can persist long term in a wide range of tissues including heart and skeletal muscle [[15], [16], [17]]. Recently, we reported that AAV markedly transduced cardiomyocytes in an infarcted rat heart and the transgene expression was observed up to 22 weeks [18].
Traditionally, the angiogenic response has been examined by evaluation of the physiological changes associated with the process. More recently, a number of investigators have demonstrated the feasibility of noninvasive evaluation of angiogenesis using image-based approaches targeted at cell surface receptors. We previously demonstrated the potential of single photon emission computed tomographic (SPECT) imaging with radiolabeled tracers targeted at αv integrins and X-ray computed tomography (CT) for evaluation of spatial and temporal changes in peripheral [19] and in myocardial angiogenesis in mice [20], rats, and dogs post-MI [21,22].
To date, there have been no reports showing the effect or mechanism of long-term IGF-1 expression on angiogenesis post-MI. In this study, we examined the IGF-1 effect on angiogenesis with both biochemical assay and microSPECT-CT imaging using 99mTc-labeled peptide (NC100692, GE Healthcare) targeted at αv integrins [23], known to be activated during angiogenic process. Here we show that AAV mediated long-term stable expression of human IGF-1 in rat heart post-MI, and overexpression of IGF-1 significantly improved cardiac function and enhanced angiogenesis in the early stage after infarction.
Section snippets
AAV vector production
To produce an AAV-CMV-IGF-1 construct, human IGF-1 cDNA, as defined in NCBI-X00173, was amplified by a standard polymerase chain reaction (PCR) method using IGF-1 specific PCR primers as shown below, using a human gene clone (clone ID: 984882, catalog no. 97002RG, Invitrogen™ Life Technologies):
5′primer: 5′-CCGAATTCTTCAGAAGCAATGGGA-3′
3′primer: 5′-CGGGATCCGTCTTCCTACATCCTG-3′
After the fragment of sequence was confirmed, the cDNA of IGF-1 was inserted
AAV-mediated IGF-1 expression in cardiac cells and tissues
We initially overexpressed the AAV-IGF-1 vector containing human IGF-1 gene in cultured rat H9C2 cells. H9C2 cells were infected with 1000 particles per cell of AAV-IGF-1, and mRNA expression of human IGF-1 was examined by RT-PCR. IGF-1 was strongly expressed in a time dependent manner through the AAV vector system (Fig. 1A). To evaluate whether the exogenous IGF-1 expression affects the infected cells, we analyzed Akt, an important effector on angiogenesis [32], after infection of control
Discussion
In this study, we demonstrated that local delivery of IGF-1 gene by recombinant AAV in the setting of acute MI resulted in sustained IGF-1 expression, increased angiogenesis, reduced LV remodeling, and improved cardiac function. The effect of AAV-IGF-1 treatment on angiogenesis was examined using an established rat model of MI with both in vitro biochemical assays for a number of angiogenic factors, and in vivo microSPECT-CT imaging using a 99mTc-labeled peptide targeted at αv integrins, known
Disclosures
Marivi Mendizabal is an employee of GE Healthcare.
Acknowledgments
We thank Dr. Douglas Losordo for support. This work was supported by Starr foundation grant (R.A.) and NIH grant R01 HL65662 (A.S.).
References (36)
- et al.
Cardiomyocyte-specific gene expression following recombinant adeno-associated viral vector transduction
J Biol Chem
(2002) - et al.
Long-term stable expression of human growth hormone by rAAV promotes myocardial protection post-myocardial infarction
J Mol Cell Cardiol
(2007) - et al.
99mTc-NC100692—a tracer for imaging vitronectin receptors associated with angiogenesis: a preclinical investigation
Nucl Med Biol
(2008 Apr) - et al.
Use of recombinant adeno-associated viral vectors as a tool for labeling bone marrow cells
J Mol Cell Cardiol
(2005) - et al.
Mice deficient in liver production of insulin-like growth factor I display sexual dimorphism in growth hormone-stimulated postnatal growth
Endocrinology
(2000) - et al.
Growth hormone, insulin-like growth factor-1 and the aging cardiovascular system
Cardiovasc Res
(2002) - et al.
Expression, regulation, and function of IGF-1, IGF-1R, and IGF-1 binding proteins in blood vessels
Arterioscler Thromb Vasc Biol
(2004) - et al.
Overexpression of insulin-like growth factor-1 in mice protects from myocyte death after infarction, attenuating ventricular dilation, wall stress, and cardiac hypertrophy
J Clin Invest
(1997) - et al.
Cardiac-specific IGF-1 expression attenuates dilated cardiomyopathy in tropomodulin-overexpressing transgenic mice
Circ Res
(2002) - et al.
Cardiac stem cell and myocyte aging, heart failure, and insulin-like growth factor-1 overexpression
Circ Res
(2004)
Transgenic overexpression of locally acting insulin-like growth factor-1 inhibits ubiquitin-mediated muscle atrophy in chronic left-ventricular dysfunction
Circ Res
Gene therapy vector-mediated expression of insulin-like growth factors protects cardiomyocytes from apoptosis and enhances neovascularization
Am J Physiol Heart Circ Physiol
Insulin-like growth factor I is required for vessel remodeling in the adult brain
Proc Natl Acad Sci U S A
Insulin-like growth factor I plasmid therapy promotes in vivo angiogenesis
Mol Ther
Adverse effects of recombinant human insulin-like growth factor I in obese insulin-resistant type II diabetic patient
Diabetes
Adeno-associated viral vector-mediated vascular endothelial growth factor gene transfer induces neovascular formation in ischemic heart
Proc Natl Acad Sci U S A
Gene therapy strategy for long-term myocardial protection using adeno-associated virus-mediated delivery of heme oxygenase gene
Circulation
Chronic suppression of heart-failure progression by a pseudophosphorylated mutant of phospholamban via in vivo cardiac rAAV gene delivery
Nat Med
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