Directed cardiomyogenesis of autologous human induced pluripotent stem cells recruited to infarcted myocardium with bioengineered antibodies

Abstract

ObjectiveMyocardial infarctions constitute a major factor contributing to non-natural mortality world-wide. Clinical trials ofmyocardial regenerative therapy, currently pursued by cardiac surgeons, involve administration of stem cells into the hearts of patients suffering from myocardial infarctions. Unfortunately, surgical acquisition of these cells from bone marrow or heart is traumatic, retention of these cells to sites of therapeutic interventions is low, and directed differentiation of these cells in situ into cardiomyocytes is difficult. The specific aims of this work were: (1) to generate autologous, human, pluripotent, induced stem cells (ahiPSCs) from the peripheral blood of the patients suffering myocardial infarctions; (2) to bioengineer heterospecific tetravalent antibodies (htAbs) and use them for recruitment of the ahiPSCs to infarcted myocardium; (3) to initiate in situ directed cardiomyogenesis of the ahiPSCs retained to infarcted myocardium.MethodsPeripheral blood was drawn from six patients scheduled for heart transplants. Mononuclear cells were isolated and reprogrammed, with plasmids carrying six genes (NANOG, POU5F1, SOX2, KLF4, LIN28A, MYC), to yield the ahiPSCs. Cardiac tissues were excised from the injured hearts of the patients, who received transplants during orthotopic surgery. These tissues were used to prepare in vitro model of stem cell therapy of infarcted myocardium. The htAbs were bioengineered, which simultaneously targeted receptors displayed on pluripotent stem cells (SSEA-4, SSEA-3, TRA-1-60, TRA-1-81) and proteins of myocardial sarcomeres (myosin, α-actinin, actin, titin). They were used to bridge the ahiPSCs to the infarcted myocardium. The retained ahiPSCs were directed with bone morphogenetic proteins and nicotinamides to differentiate towards myocardial lineage.ResultsThe patients’ mononuclear cells were efficiently reprogrammed into the ahiPSCs. These ahiPSCs were administered to infarcted myocardium in in vitro models. They were recruited to and retained at the treated myocardium with higher efficacy and specificity, if were preceded the htAbs, than with isotype antibodies or plain buffers. The retained cells differentiated into cardiomyocytes.ConclusionsThe proof of concept has been attained, for reprogramming the patients’ blood mononuclear cells (PBMCs) into the ahiPSCs, recruiting these cells to infarcted myocardium, and initiating their cardiomyogenesis. This novel strategy is ready to support the ongoing clinical trials aimed at regeneration of infarcted myocardium.

Bioengineering Human Myocardium on Native Extracellular Matrix

“…In cardiac regeneration, techniques have been developed for the delivery of human iPS-derived cardiac myocytes to improve cardiac function post-infarct 7, 60 , provide cardioprotection 61 , and enhance homing and survival in infarcted myocardium 62 . These approaches build on the extensive body of literature on ES derived cardiac myocytes, which have been recently reported to mediate myogenesis in a primate model of cardiac repair 32 .…”

Fibroblast–myocyte coupling in the heart: Potential relevance for therapeutic interventions

“…Therapies of this type may be challenged by the fact that many more bone marrow cells would be transfected than those that home in to sites of cardiac injury [136]. This could be addressed, however, using ‘auto-terminating’ transfection strategies, or by the use of heterospecific antibodies, which have been shown to increase engraftment of intravascularly injected cells in the heart [137]. These antibodies are engineered to be specific for the antigens of two cell types.…”

Fibrin‐targeting delivery: a novel platform for cardiac regenerative medicine

“…However, the cytokine-based method has been far away from being able to effectively regulate stem cells migrating to target tissue due to the extremely complicity of the cytokine interaction and the homing molecular mechanisms [11,12]. Recently, components released from injured cardiomyocyte (such as myosin light chain, actin and myosin associated proteins) have been explored as novel homing targets [13][14][15][16]. However, cardiomyocyte components may also release into the bloodstream, weakening the specificity of tissue distribution.…”