Gene therapy: targeting the myocardium

Lyon, Alexander R.; Sato, Motoki; Hajjar, Roger J.; Samulski, R. Jude; Harding, Siân E.

doi:10.1136/hrt.2007.116483

Cited by 91 publications

(52 citation statements)

References 94 publications

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“…Using cellular tissue-specific promoters or gene regulation components that can be expressed excessively in some pathological states is expected to guide the high-level expression of a theoretical gene to a particular tissue [8,9] . The objective of gene therapy is to achieve efficient and punctual expression of a theoretical gene in a particular cell type [10,11] . The objective of the present study was to increase transcriptional targeting in gene therapy.…”

Section: Discussionmentioning

confidence: 99%

The targeting expression of the vascular endothelial growth factor gene in endothelial cells regulated by HRE.ppET-1

et al. 2008

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The success of gene therapy depends largely on the efficacy of gene delivery vector systems that can deliver genes to target organs or cells selectively and efficiently with minimal toxicity. Here, we show that by using the HRE.ppET-1 regulatory element, we were able to restrict expression of the transgene of vascular endothelial growth factor (VEGF) to endothelial cells exclusively in hypoxic conditions. Eukaryotic expression vectors such as pEGFP-HRE.ppET-1, pcDNA3.1-VEGF+Pa, pcDNA3.1-ppET-1+ EGF+Pa, and pcDNA3.1-HRE.ppET-1+VEGF+Pa were constructed by using a series of nuclear molecule handling methods like PCR, enzyme digestion. The recombinant vectors were transfected into HUVEC cells and HL7702 cells by the lipofectin method. GFP expression was observed with a fluorescence microscope to validate the specificity of expression in endothelial cells under the regulation of HRE.ppET-1 element. Cobalt chloride (final concentration 100 mumol/L) was added to the medium to mimic hypoxia in vitro. After transfection of vectors, the expression of VEGF mRNA was detected by RT-PCR, and the expression of VEGF was detected by Western blotting and ELISA methods under normoxia and hypoxia, respectively. The cell proliferation rate was detected by the MTT test. The expression of GFP revealed that the exterior gene was transcripted effectively in endothelial cells regulated by the HRE.ppET-1 element, while the expression of GFP was very weak in nonendothelial cells. The results of RT-PCR, Western blotting and ELISA showed that VEGF gene expression in the pcDNA3.1-HRE.ppET-1+VEGF+Pa group and in the pcDNA3.1-ppET-1+VEGF+Pa group was higher in hypoxia than it was in normoxia (P<0.05). The MTT test showed that the proliferation rate of HUVEC transfected with HPVA under hypoxia exceeded that of the control group. We conclude that the HRE.ppET-1 element was expressed specifically in endothelial cells, and can increase the expression of VEGF in hypoxia and stimulate proliferation of endothelial cells. Taking advantage of these facts could greatly improve the efficiency of gene therapy. The vector would be valuable for various gene transfer studies targeting endothelial cells.

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Section: Discussionmentioning

confidence: 99%

The targeting expression of the vascular endothelial growth factor gene in endothelial cells regulated by HRE.ppET-1

et al. 2008

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“…Introducing the transgene into hMSCs ex vivo minimizes the risk of the former effect, whereas switching to a cell-specific promoter would minimize the latter. However, using a cell-specific promoter is likely, at least in the short term, to result in a lower expression level and therefore reduced current [70]. In addition, if the hMSC phenotype changes following in vivo implantation, promoter activity could be affected.…”

Section: The Challenge: Improving Outcomementioning

confidence: 94%

Bradyarrhythmia Therapies: The Creation of Biological Pacemakers and Restoring Atrioventricular Node Function

Robinson

2011

Regenerating the Heart

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In the USA, over 300,000 electronic pacemakers are implanted annually to treat slow heart rates resulting from abnormal sinus or atrioventricular (AV) node function. Although life-saving, limitations and problems with this hardware-based approach have led to interest in using gene and cell delivery methods to develop purely biological based therapies. The goal in creating a biological pacemaker or AV bypass is not to replicate the sinus or AV nodes at a cellular or molecular level, but rather to recreate their functionality. There has been more research on biological pacemakers than on AV bypasses, and the former has explored both implantation of endogenously automatic cells and genetic engineering methods, with the latter involving either direct gene delivery or gene delivery to stem cells that are subsequently implanted into the myocardium. This makes use of all the tools of bioinformatics and molecular biology to engineer custom channels with distinct biophysical properties that may be best suited for a specific patient population or implant site. Although various gene products have been targeted as the basis of a biological pacemaker, most recent efforts have focused on the HCN gene family of pacemaker current. These channels open on hyperpolarization, so they contribute current largely during diastole and have minimal impact on action potential duration. Further, these channels directly bind and respond to the adrenergic second messenger cyclic AMP, so autonomic responsiveness is integral to an HCN-based biological pacemaker. Although proof of principle has been demonstrated by a number of laboratories in several model systems, numerous challenges remain to achieve physiologically appropriate rates with sufficient robustness. Before clinical trials can begin, critical issues of safety and persistence of function must first be addressed in long-term animal studies. Even then, the appropriate patient population will be limited until a biological AV bypass is also developed to ensure AV

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“…It has become clear that the abundance of many proteins that play critical roles in the control of cardiomyocyte structure and function are altered in the setting of heart failure. The theoretical basis for gene transfer therapy is that the delivery of genetic material into cardiac cells can serve to augment (or repress) expression of genes that encode these proteins in cardiomyocytes in the failing heart [83]. Adverse events that occurred in the course of early clinical trials [84,85] slowed development of this promising approach for some time and ultimately gave rise to stricter regulatory control.…”

Section: Gene Transfermentioning

confidence: 99%