Transient secretion of VEGF protein from transplanted hiPSC-CMs enhances engraftment and improves rat heart function post MI.

Cell-based therapies offer an exciting and novel treatment for heart repair following myocardial infarction (MI). However, these therapies often suffer from poor cell viability and engraftment rates, which involve many factors, including the hypoxic conditions of the infarct environment. Meanwhile, vascular endothelial growth factor (VEGF) has previously been employed as a therapeutic agent to limit myocardial damage and simultaneously induce neovascularization. This study took an approach to transiently overexpress VEGF protein, in a controlled manner, by transfecting human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) with VEGF mRNA prior to transplantation. The conditioning of iPSC-CMs with VEGF mRNA ultimately led to greater survival rates of the transplanted cells, which promoted a stable vascular network in the grafted region. Furthermore, bulk RNA transcriptomics data and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that phosphoinositide 3-kinase (PI3K)-protein kinase B (Akt) and AGE-RAGE signaling pathways were significantly upregulated in the VEGF-treated iPSC-CMs group. The over-expression of VEGF from iPSC-CMs stimulated cell proliferation and partially attenuated the hypoxic environment in the infarcted area, resulting in reduced ventricular remodeling. This study provides a valuable solution for the survival of transplanted cells in tissue-engineered heart regeneration and may further promote the application of modified mRNA (modRNA) in the field of tissue engineering.

Engineering a conduction-consistent cardiac patch with graphene oxide modified butterfly wings and human pluripotent stem cell-derived cardiomyocytes.

Engineering a conduction-consistent cardiac patch has direct implications to biomedical research. However, there is difficulty in obtaining and maintaining a system that allows researchers to study physiologically relevant cardiac development, maturation, and drug screening due to the issues around inconsistent contractions of cardiomyocytes. Butterfly wings have special nanostructures arranged in parallel, which could help generate the alignment of cardiomyocytes to better mimic the natural heart tissue structure. Here, we construct a conduction-consistent human cardiac muscle patch by assembling human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) on graphene oxide (GO) modified butterfly wings. We also show this system functions as a versatile model to study human cardiomyogenesis by assembling human induced pluripotent stem cell-derived cardiac progenitor cells (hiPSC-CPCs) on the GO modified butterfly wings. The GO modified butterfly wing platform facilitated the parallel orientation of hiPSC-CMs, enhanced relative maturation as well as improved conduction consistency of the cardiomyocytes. In addition, GO modified butterfly wings enhanced the proliferation and maturation characteristics of the hiPSC-CPCs. In accordance with data obtained from RNA-sequencing and gene signatures, assembling hiPSC-CPCs on GO modified butterfly wings stimulated the differentiation of the progenitors into relatively mature hiPSC-CMs. These characteristics and capabilities of GO modified butterfly wings make them an ideal platform for heart research and drug screening.

Vascular endothelial growth factor a modified mRNA engineered cellular electrospun membrane complexes promotes mouse skin wound repair.

Artificial skin substitutes are one of the most promising areas of wound healing research; however, graft survival largely depends on how the treatment is performed. Early angiogenesis is essential for wound healing and graft survival and vascular endothelial growth factor A (VEGFA) is an important cytokine that stimulates angiogenesis. Here, we first investigated the effects of different ratios of collagen (BC) and gelatin blended with poly (l-lactide-co-caprolactone) (PLCL) on nanofibrous membranes. The Young's modulus and cell proliferation were significantly higher in the 50% BC group than that in all other groups. Then, cellular electrospun membrane complexes (CEMC) were successfully constructed from nanoscaffolds and fibroblasts extracted from human foreskin and engineered with controlled autocrine VEGFA by transfecting VEGFA modified mRNA (modRNA). Engineered CEMC significantly promoted wound healing in vivo and contributed to stable vascular network formation in the grafted area, thereby increasing the survival rate of the engineered skin. This study provides a potential solution for wound healing while establishing the value of different RNA modification methods for various engineered skins in the future, thereby advancing engineered skin development.

Engineering a conduction-consistent cardiac patch with rGO/PLCL electrospun nanofibrous membranes and human iPSC-derived cardiomyocytes.

The healthy human heart has special directional arrangement of cardiomyocytes and a unique electrical conduction system, which is critical for the maintenance of effective contractions. The precise arrangement of cardiomyocytes (CMs) along with conduction consistency between CMs is essential for enhancing the physiological accuracy of in vitro cardiac model systems. Here, we prepared aligned electrospun rGO/PLCL membranes using electrospinning technology to mimic the natural heart structure. The physical, chemical and biocompatible properties of the membranes were rigorously tested. We next assembled human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) on electrospun rGO/PLCL membranes in order to construct a myocardial muscle patch. The conduction consistency of cardiomyocytes on the patches were carefully recorded. We found that cells cultivated on the electrospun rGO/PLCL fibers presented with an ordered and arranged structure, excellent mechanical properties, oxidation resistance and effective guidance. The addition of rGO was found to be beneficial for the maturation and synchronous electrical conductivity of hiPSC-CMs within the cardiac patch. This study verified the possibility of using conduction-consistent cardiac patches to enhance drug screening and disease modeling applications. Implementation of such a system could one day lead to in vivo cardiac repair applications.

Safe and Effective Delivery of mRNA Using Modified PEI-Based Lipopolymers.

Chemically modified mRNA (modRNA) has proven to be a versatile tool for the treatment of various cancers and infectious diseases due to recent technological advancements. However, a safe and effective delivery system to overcome the complex extracellular and intracellular barriers is required in order to achieve higher therapeutic efficacy and broaden clinical applications. Here, we explored All-Fect and Leu-Fect C as novel transfection reagents derived from lipopolymers, which demonstrated excellent biocompatibility, efficient delivery capabilities, and a robust ability to escape the lysosomes. These properties directly increase mRNA stability by preventing mRNA degradation by nucleases and simultaneously promote efficient gene translation in vitro and in vivo. The modRNA delivered with lipopolymer vectors sustained effective transfection in mouse hearts following direct intramyocardial injection, as well as in major organs (liver and spleen) after systemic administration. No observable immune reactions or systemic toxicity were detected following the systemic administration of lipopolymer-mRNA complexes to additional solid organs. This study identified commercial reagents for the effective delivery of modRNA and may help facilitate the advancement of gene-based interventions involving the safe and effective delivery of nucleic acid drug substances.