Conditioned media from human pluripotent stem cell-derived cardiomyocytes inhibit the growth and migration of lung cancer cells.

Conditioned media (CM) from various cell types contain significant levels of paracrine factors. Recently, therapeutic properties of CM derived from stem cells have been revealed. Based on the fact that heart cancer is extremely rarely, we hypothesized that the CM obtained from human pluripotent stem cell-derived cardiomyocytes might inhibit cancer cell growth and survival. To this end, lung cancer cell line A549 along with human foreskin fibroblasts (HFF) were treated with serial concentrations of cardiomyocyte CM (CCM) or fibroblast CM (FCM). We found that CCM markedly reduced the viability of lung cancer cells, while FCM did not compromise the viability of neither cancer cells nor HFF cells. Furthermore, we determined an optimized CCM concentration, 30 mg/mL, at which the growth, clonogenicity, and migration of A549 and Calu6 lung cancer cell lines were substantially impaired, whereas FCM did not influence these properties. Moreover, lung cancer cells exhibited cell cycle regulation upon treatment with CCM and the rate of apoptosis was markedly increased by cardiomyocyte CM in both lung cancer cell lines tested. Finally, in response to CCM treatment, A549 and Calu6 cells expressed lower levels of antiapoptotic and stemness genes, but higher levels of proapoptotic genes. In conclusion, this study provides cellular and molecular evidence for the antitumor ability of secretome obtained from stem cell-derived cardiomyocytes.

How does caspases regulation play role in cell decisions? apoptosis and beyond.

Caspases are a family of cysteine proteases, and the key factors behind the cellular events which occur during apoptosis and inflammation. However, increasing evidence shows the non-conventional pro-survival action of apoptotic caspases in crucial processes. These cellular events include cell proliferation, differentiation, and migration, which may appear in the form of metastasis, and chemotherapy resistance in cancerous situations. Therefore, there should be a precise and strict control of caspases activity, perhaps through maintaining the threshold below the required levels for apoptosis. Thus, understanding the regulators of caspase activities that render apoptotic caspases as non-apoptotic is of paramount importance both mechanistically and clinically. Furthermore, the functions of apoptotic caspases are affected by numerous post-translational modifications. In the present mini-review, we highlight the various mechanisms that directly impact caspases with respect to their anti- or non-apoptotic functions. In this regard, post-translational modifications (PTMs), isoforms, subcellular localization, transient activity, substrate availability, substrate selection, and interaction-mediated regulations are discussed.

The quest of cell surface markers for stem cell therapy.

Stem cells and their derivatives are novel pharmaceutics that have the potential for use as tissue replacement therapies. However, the heterogeneous characteristics of stem cell cultures have hindered their biomedical applications. In theory and practice, when cell type-specific or stage-specific cell surface proteins are targeted by unique antibodies, they become highly efficient in detecting and isolating specific cell populations. There is a growing demand to identify reliable and actionable cell surface markers that facilitate purification of particular cell types at specific developmental stages for use in research and clinical applications. The identification of these markers as very important members of plasma membrane proteins, ion channels, transporters, and signaling molecules has directly benefited from proteomics and tools for proteomics-derived data analyses. Here, we review the methodologies that have played a role in the discovery of cell surface markers and introduce cutting edge single cell proteomics as an advanced tool. We also discuss currently available specific cell surface markers for stem cells and their lineages, with emphasis on the nervous system, heart, pancreas, and liver. The remaining gaps that pertain to the discovery of these markers and how single cell proteomics and identification of surface markers associated with the progenitor stages of certain terminally differentiated cells may pave the way for their use in regenerative medicine are also discussed.

Hydrogel-mediated delivery of microRNA-92a inhibitor polyplex nanoparticles induces localized angiogenesis.

Localized stimulation of angiogenesis is an attractive strategy to improve the repair of ischemic or injured tissues. Several microRNAs (miRNAs) such as miRNA-92a (miR-92a) have been reported to negatively regulate angiogenesis in ischemic disease. To exploit the clinical potential of miR-92a inhibitors, safe and efficient delivery needs to be established. Here, we used deoxycholic acid-modified polyethylenimine polymeric conjugates (PEI-DA) to deliver a locked nucleic acid (LNA)-based miR-92a inhibitor (LNA-92a) in vitro and in vivo. The positively charged PEI-DA conjugates condense the negatively charged inhibitors into nano-sized polyplexes (135 ± 7.2 nm) with a positive net charge (34.2 ± 10.6 mV). Similar to the 25 kDa-branched PEI (bPEI25) and Lipofectamine RNAiMAX, human umbilical vein endothelial cells (HUVECs) significantly internalized PEI-DA/LNA-92a polyplexes without any obvious cytotoxicity. Down-regulation of miR-92a following the polyplex-mediated delivery of LNA-92a led to a substantial increase in the integrin subunit alpha 5 (ITGA5), the sirtuin-1 (SIRT1) and Krüppel-like factors (KLF) KLF2/4 expression, formation of capillary-like structures by HUVECs, and migration rate of HUVECs in vitro. Furthermore, PEI-DA/LNA-92a resulted in significantly enhanced capillary density in a chicken chorioallantoic membrane (CAM) model. Localized angiogenesis was substantially induced in the subcutaneous tissues of mice by sustained release of PEI-DA/LNA-92a polyplexes from an in situ forming, biodegradable hydrogel based on clickable poly(ethylene glycol) (PEG) macromers. Our results indicate that PEI-DA conjugates efficiently deliver LNA-92a to improve angiogenesis. Localized delivery of RNA interference (RNAi)-based therapeutics via hydrogel-laden PEI-DA polyplex nanoparticles appears to be a safe and effective approach for different therapeutic targets.

A novel fluorescent cardiac imaging system for preclinical intraoperative angiography.

BACKGROUND: Intraoperative coronary angiography can tremendously reduce early coronary bypass graft failures. Fluorescent cardiac imaging provides an advanced method for intraoperative observation and real-time quantitation of blood flow with high resolution. METHODS: We devised a system comprised of an LED light source, special filters, lenses and a detector for preclinical coronary artery angiography. The optical setup was implemented by using two achromatic doublet lenses, two positive meniscus lenses, a band-pass filter, a pinhole and a CCD sensor. The setup was optimized by Zemax software. Optical design was further challenged to obtain more parallel light beams, less diffusion and higher resolutions to levels as small as arterioles. Ex vivo rat hearts were prepared and coronary arteries were retrogradely perfused by indocyanine green (ICG). Video angiography was employed to assess blood flow and plot time-dependent fluorescence intensity curve (TIC). Quantitation of blood flow was performed by calculating either the gradient of TIC or area under curve. The correlation between blood flow and each calculated parameters was assessed and used to evaluate the quality of flow. RESULTS: High-resolution images of flow in coronary arteries were obtained as precise as 62 µm vessel diameter, by our custom-made ICG angiography system. The gradient of TIC was 3.4-6.3 s-1, while the area under curve indicated 712-1282 s values which ultimately gained correlation coefficients of 0.9938 and 0.9951 with relative blood flow, respectively. CONCLUSION: The present ICG angiography system may facilitate evaluation of blood flow in animal studies of myocardial infarction and coronary artery grafts intraoperatively.

Mesenchymal stem cell-derived extracellular vesicles alone or in conjunction with a SDKP-conjugated self-assembling peptide improve a rat model of myocardial infarction.

PURPOSE: The aim of this study was to investigate the cardiac repair effect of human bone marrow mesenchymal stromal cells-derived extracellular vesicles (MSC-EVs) after intramyocardial injection in free form or encapsulated within a self-assembling peptide hydrogel modified with SDKP motif, in a rat model of myocardial infarction (MI). METHODS: MSC-EVs were isolated by ultracentrifuge and characterized for physical parameters and surface proteins. Furthermore, cellular uptake and cardioprotective effects of MSC-EVs were evaluated in vitro using neonatal mouse cardiomyocytes (NMCMs). In vivo effects of MSC-EVs on cardiac repair were studied in rat MI model by comparing the vehicle group (injected with PBS), EV group (injected with MSC-EVs) and Gel + EV group (injected with MSC-EVs encapsulated in (RADA)4-SDKP hydrogel) with respect to cardiac function and fibrotic area using echocardiography and Masson's trichrome staining, respectively. Histological sections were assessed by α-SMA and CD68 immunostaining to investigate the angiogenic and anti-inflammatory effects of the MSC-EVs. RESULTS: We observed the uptake of MSC-EVs into NMCMs which led to NMCMs protection against H2O2-induced oxidative stress by substantial reduction of apoptosis. In myocardial infarcted rats, cardiac function was improved after myocardial injection of MSC-EVs alone or in conjunction with (RADA)4-SDKP hydrogel. This functional restoration coincided with promotion of angiogenesis and decrement of fibrosis and inflammation. CONCLUSION: These data demonstrated that MSC-EVs can be used alone as a potent therapeutic agent for improvement of myocardial infarction.

How does proteomics target plant environmental stresses in a semi-arid area?

Southwest Asia, in most parts, is recognized as arid and semi-arid ecosystems (For instance around 90% in Iran). Abiotic stresses, especially salt and drought, are main stresses in this region that limit the crop yields. Furthermore, the level of soil salinization is increasing. Therefore, many researchers are focusing on these two stresses. Specifically, in Iran, the use of plant proteomics dates back to more than a decade. During these years, many researchers employed this powerful technique to elucidate molecular basis of plant response to cope with environmental stresses and to apply related mechanisms to generate stress-tolerant varieties. PlantPRes (www.proteome.ir) which is a database for Plant Proteome Response to stress has been recently established. In this review, we discuss the work which has been done by plant proteomics researchers and their corresponding publications to identify the molecular mechanisms underlying drought-, salt-, heat-, cold- and biotic-tolerance in plants followed by a whole data integration to depict a detailed picture of upregulated or downregulated cellular functions for important goal of generating more resilient cultivars appropriate for semi-arid climate.

Down-Regulation of a Male-Specific H3K4 Demethylase, KDM5D, Impairs Cardiomyocyte Differentiation.

Despite the small number of Y chromosome genes, their adequate expression is required for regulation of transcription, translation, and protein stability in males, not just for sex determination. In addition to the role in male fertility, the Y chromosome has a significant role in the development and sexual dimorphism of healthy and disease phenotypes. We observed that KDM5D along with its X-counterpart, KDM5C, are up-regulated during the cardiac mesoderm stage of development. Down-regulation of KDM5D using siRNA resulted in accumulation of differentiating cells in the S-phase of the cell cycle and impaired progression to cardiomyocytes as reflected by an altered expression pattern of cardiac progenitor specific markers. Furthermore, while control cells started spontaneous beating at a normal physiological range on day 7 of differentiation induction, no spontaneous beating was observed in KDM5D down-regulated cells. Interestingly, the knockdown of KDM5D had no significant effect on the expression level of its X-counterpart, KDM5C. Thus, we suggest that KDM5D, in cooperation with its X homologue as a dose-sensitive gene, may have an important role in cardiomyocyte differentiation. Our study presents further evidence on the contribution of Y chromosome genes to sex-dependent development outside of sex determination.

Coculture with noncardiac cells promoted maturation of human stem cell-derived cardiomyocyte microtissues.

Cardiomyocytes derived from human pluripotent stem cells (hPSC-CM) provided a promising cell source for cell therapy, drug screening, and disease modeling. However, hPSC-CM are immature and phenotypically more similar to fetal rather than adult cardiomyocytes in vitro. We explored the impact of coculture of human embryonic stem cell-derived mesenchymal stem cells (hESC-MSC) and endothelial cells (ECs) with human embryonic stem cells-derived cardiac progenitor cells (hESC-CPC) on the gene expression and electrophysiological properties of hESC-CPC in 3D culture (microtissue spheroid). In this regard, hESC-CPC were cultured either alone (CM microtissue) or in coculture with EC and hESC-MSC (CMEM microtissue) on agar-coated 96-well round-bottomed plates for 1 week. Lumen-like structures were formed in CMEM but not in CM microtissue. Cardiac progenitor markers (TBX5, GATA4) were downregulated and cardiac sarcomeric transcripts (MLC2v and ß-MHC) were upregulated in CMEM compared with CM microtissue. Furthermore, beating frequencies, beating cycles, and field potential durations of CMEM resided in the range of adult cardiomyocytes rather than fetal like phenotypes observed in CM microtissue. These findings demonstrated that CPC spheroids in coculture with EC and hESC-MSC may undergo greater maturation toward an adult-like cardiomyocyte.

Effects of hawthorn ( Crataegus pentagyna) leaf extract on electrophysiologic properties of cardiomyocytes derived from human cardiac arrhythmia-specific induced pluripotent stem cells.

Cardiac arrhythmias are major life-threatening conditions. The landmark discovery of induced pluripotent stem cells has provided a promising in vitro system for modeling hereditary cardiac arrhythmias as well as drug development and toxicity testing. Nowadays, nutraceuticals are frequently used as supplements for cardiovascular therapy. Here we studied the cardiac effects of hawthorn ( Crataegus pentagyna) leaf extract using cardiomyocytes (CMs) differentiated from healthy human embryonic stem cells, long QT syndrome type 2 (LQTS2), and catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) patient-specific induced pluripotent stem cells. The hydroalcoholic extract resulted in a dose-dependent negative chronotropic effect in all CM preparations leading to a significant reduction at 1000 µg/ml. This was accompanied by prolongation of field potential durations, although with different magnitudes in CMs from different human embryonic stem cell and iPSC lines. Hawthorn further prolonged field potential durations in LQTS2 CMs but reduced the beating frequencies and occurrence of immature field potentials triggered by ß1-adrenergic stimulation in CPVT1 CMs at 300 and 1000 µg/ml. Furthermore, isoquercetin and vitexin flavonoids significantly slowed down isoproterenol (5 µM)-induced beating frequencies at 3 and 10 µg/ml. Therefore, C. pentagyna leaf extract and its isoquercetin and vitexin flavonoids may be introduced as a novel nutraceutical with antiarrhythmic potential for CPVT1 patients.-Pahlavan, S., Tousi, M. S., Ayyari, M., Alirezalu, A., Ansari, H., Saric, T., Baharvand, H. Effects of hawthorn ( Crataegus pentagyna) leaf extract on electrophysiologic properties of cardiomyocytes derived from human cardiac arrhythmia-specific induced pluripotent stem cells.

17th Chromosome-Centric Human Proteome Project Symposium in Tehran.

This report describes the 17th Chromosome-Centric Human Proteome Project which was held in Tehran, Iran, April 27 and 28, 2017. A brief summary of the symposium's talks including new technical and computational approaches for the identification of novel proteins from non-coding genomic regions, physicochemical and biological causes of missing proteins, and the close interactions between Chromosome- and Biology/Disease-driven Human Proteome Project are presented. A synopsis of decisions made on the prospective programs to maintain collaborative works, share resources and information, and establishment of a newly organized working group, the task force for missing protein analysis are discussed.

Reversible permeabilization of the mitochondrial membrane promotes human cardiomyocyte differentiation from embryonic stem cells.

Cell death and differentiation appear to share similar cellular features. In this study, we aimed to investigate whether differentiation and mitochondrial cell death use a common pathway. We assessed the hallmarks of apoptosis during cardiomyocyte differentiation of human embryonic stem cells and found remarkable changes in P53, reactive oxygen species, apoptotic protease-activating factor 1, poly[ADP-ribose]polymerase 1, cellular adenosine triphosphate, and mitochondrial complex I activity. Furthermore, we observed reversible mitochondrial membrane permeabilization during cardiomyocyte differentiation accompanied by reversible loss of mitochondrial membrane potential, and these changes coincided with the fluctuating patterns of cytosolic cytochrome c accumulation and subsequent caspase-9 and -3/7 activation. Moreover, the use of apoptosis inhibitors (BCL2-associated X protein [BAX] inhibitor and caspase-3/7 inhibitor) during differentiation impaired cardiomyocyte development, resulting in substantial downregulation of T, MESP1, NKX2.5, and α-MHC. Additionally, although the expression of specific differentiation markers (T, MESP1, NKX2.5, MEF2C, GATA4, and SOX17) was enhanced in doxorubicin-induced human embryonic stem cells, the stemness-specific markers (OCT4 and NANOG) showed significant downregulation. With increasing doxorubicin concentration (0.03-0.6 µM; IC50 = 0.5 µM), we observed a marked increase in the expression of mesoderm and endoderm markers. In summary, we suggest that reversible mitochondrial outer membrane permeabilization promotes cardiomyocyte differentiation through an attenuated mitochondria-mediated apoptosis-like pathway.

Y Chromosome Missing Protein, TBL1Y, May Play an Important Role in Cardiac Differentiation.

Despite evidence for sex-specific cardiovascular physiology and pathophysiology, the biological basis for this dimorphism remains to be explored. Apart from hormonal factors, gender-related characteristics may reside in the function of sex chromosomes during cardiac development. In this study, we investigated the differential expression of the male-specific region of the Y chromosome (MSY) genes and their X counterparts during cardiac differentiation of human embryonic stem cells (hESC). We observed alterations in mRNA and protein levels of TBL1Y, PCDH11Y, ZFY, KDM5D, USP9Y, RPS4Y1, DDX3Y, PRY, XKRY, BCORP1, RBMY, HSFY, and UTY, which accompanied changes in intracellular localization. Of them, the abundance of a Y chromosome missing protein, TBL1Y, showed a significant increase during differentiation while the expression level of its X counterpart decreased. Consistently, reducing TBL1Y cellular level using siRNA approach influenced cardiac differentiation by reducing its efficacy as well as increasing the probability of impaired contractions. TBL1Y knockdown may have negatively impacted cardiogenesis by CtBP stabilization. Furthermore, we presented compelling experimental evidence to distinguish TBL1Y from TBL1X, its highly similar X chromosome homologue, and proposed reclassification of TBL1Y as "found missing protein" (PE1). Our results demonstrated that MSY proteins may play an important role in cardiac development.

Chromosome-Centric Human Proteome Project Allies with Developmental Biology: A Case Study of the Role of Y Chromosome Genes in Organ Development.

One of the main goals of Chromosome-Centric Human Proteome Project is to identify protein evidence for missing proteins (MPs). Here, we present a case study of the role of Y chromosome genes in organ development and how to overcome the challenges facing MPs identification by employing human pluripotent stem cell differentiation into cells of different organs yielding unprecedented biological insight into adult silenced proteins. Y chromosome is a male-specific sex chromosome which escapes meiotic recombination. From an evolutionary perspective, Y chromosome has preserved 3% of ancestral genes compared to 98% preservation of the X chromosome based on Ohno's law. Male specific region of Y chromosome (MSY) contains genes that contribute to central dogma and govern the expression of various targets throughout the genome. One of the most well-known functions of MSY genes is to decide the male-specific characteristics including sex, testis formation, and spermatogenesis, which are majorly formed by ampliconic gene families. Beyond its role in sex-specific gonad development, MSY genes in coexpression with their X counterparts, as single copy and broadly expressed genes, inhibit haplolethality and play a key role in embryogenesis. The role of X-Y related gene mutations in the development of hereditary syndromes suggests an essential contribution of sex chromosome genes to development. MSY genes, solely and independent of their X counterparts and/or in association with sex hormones, have a considerable impact on organ development. In this Review, we present major recent findings on the contribution of MSY genes to gonad formation, spermatogenesis, and the brain, heart, and kidney development and discuss how Y chromosome proteome project may exploit developmental biology to find missing proteins.

Ascorbic acid promotes the direct conversion of mouse fibroblasts into beating cardiomyocytes.

Recent advances in the direct conversion of fibroblasts to cardiomyocytes suggest this process as a novel promising approach for cardiac cell-based therapies. Here, by screening the effects of 10 candidate small molecules along with transient overexpression of Yamanaka factors, we show ascorbic acid (AA), also known as vitamin C, enhances reprogramming of mouse fibroblasts into beating cardiomyocytes. Immunostaining and gene expression analyses for pluripotency and cardiac lineage markers confirmed beating patches were derived from non-cardiac lineage cells without passing through a pluripotent intermediate. Further analysis revealed that AA also increased the size of the beating areas and the number of cardiac progenitors. Immunostaining for cardiac markers, as well as electrophysiological analysis confirmed the functionality of directly converted cardiomyocytes. These results illustrate the importance of AA in direct conversion of fibroblasts to cardiomyocytes and may open new insights into future biomedical applications for induced cardiomyocytes.

Exogenous treatment with eicosapentaenoic acid supports maturation of cardiomyocytes derived from embryonic stem cells.

Embryonic stem cells offer multiple advantages over adult stem cells in terms of achieving acceptable number of functional cardiomyocytes to be exploited in cell therapy. However, differentiation efficacy is still a major issue to be solved before moving to regenerative medicine. Although a vast number of chemical compounds have been tested on efficiency of cardiac differentiation, the effect of fish oil components, such as eicosapentaenoic acid (EPA) on developmental bioenergetics, and hence cardiac differentiation, remained unstudied. EPA has been reported to have several cardioprotective effects, but there is no study addressing its role in cardiac differentiation. After mesoderm induction of embryoid bodies (EBs) derived from mouse embryonic stem cells (mESCs) in hanging drops initiated by ascorbic acid, they were treated with various concentrations of EPA. Gene and protein expression and functional properties of cardiomyocytes derived from ESCs were evaluated following treatment with various concentrations of EPA. Exposure to low concentrations of EPA (10 µM) increased percentage of beating colonies and beating area. This treatment also resulted in up to 3 fold increase in expression of NKX2-5, MEF2C, MYH6, TNNT2 and CX43. FACS analysis confirmed gene expression analysis with increased percentage of MYH6 positive cells in EPA-treated group compared to the control group. In contrast, the expression of genes coding for cardiac differentiation, remained constant or even declined with higher concentrations of EPA. In conclusion, we have demonstrated that treatment of mESCs undergoing cardiac differentiation with low concentration, but not high concentration of EPA up-regulate transcription of genes associated with cardiac development.

A Non-Apoptotic Pattern of Caspase-9/Caspase-3 Activation During Differentiation of Human Embryonic Stem Cells into Cardiomyocytes.

In vitro studies have demonstrated that the differentiation of embryonic stem cells (ESCs) into cardiomyocytes requires activation of caspases through the mitochondrial pathway. These studies have relied on synthetic substrates for activity measurements, which can be misleading due to potential none-specific hydrolysis of these substrates by proteases other than caspases. Hence, caspase-9 and caspase-3 activation are investigated during the differentiation of human ESCs (hESCs) by directly assessing caspase-9 and -3 cleavage. Western blot reveals the presence of the cleaved caspase-9 prior to and during the differentiation of human ESCs (hESCs) into cardiomyocytes at early stages, which diminishes as the differentiation progresses, without cleavage and activation of endogenous procaspase-3. Activation of exogenous procaspase-3 by endogenous caspase-9 and subsequent cleavage of chromogenic caspase-3 substrate i.e. DEVD-pNA during the course of differentiation confirmes that endogenous caspase-9 has the potency to recognize and activate procaspase-3, but for reasons that are unknown to us fails to do so. These observations suggest the existence of distinct mechanisms of caspase regulation in differentiation as compared to apoptosis. Bioinformatics analysis suggests the presence of caspase-9 regulators, which may influence proteolytic function under specific conditions.

ROS scavenging activity of polydopamine nanoparticle-loaded supramolecular gelatin-based hydrogel promoted cardiomyocyte proliferation.

Reactive oxygen species (ROS) play essential roles in cellular functions, but maintaining ROS balance is crucial for effective therapeutic interventions, especially during cell therapy. In this study, we synthesized an injectable gelatin-based hydrogel, in which polydopamine nanoparticles were entrapped using supramolecular interactions. The surfaces of the nanoparticles were modified using adamantane, enabling their interactions with ß-cyclodextrin-conjugated with gelatin. We evaluated the cytotoxicity and antioxidant properties of the hydrogel on neonatal rat cardiomyocytes (NRCM), where it demonstrated the ability to increase the metabolic activity of NRCMs exposed to hydrogen peroxide (H2O2) after 5 days. Hydrogel-entrapped nanoparticle exhibited a high scavenging capability against hydroxyl radical, 1'-diphenyl-2-picrylhydrazyl radicals, and H2O2, surpassing the effectiveness of ascorbic acid solution. Notably, the presence of polydopamine nanoparticles within the hydrogel promoted the proliferation activity of NRCMs, even in the absence of excessive ROS due to H2O2 treatment. Additionally, when the hydrogel with nanoparticles was injected into an air pouch model, it reduced inflammation and infiltration of immune cells. Notably, the levels of anti-inflammatory factors, IL-10 and IL-4, were significantly increased, while the pro-inflammatory factor TNF-α was suppressed. Therefore, this novel ROS-scavenging hydrogel holds promise for both efficient cell delivery into inflamed tissue and promoting tissue repair.

Expandable hESC-derived cardiovascular progenitor cells generate functional cardiac lineage cells for microtissue construction.

BACKGROUND: Cardiovascular progenitor cells (CPCs) derived from human embryonic stem cells (hESCs) are considered valuable cell sources for investigating cardiovascular physiology in vitro. Meeting the diverse needs of this application requires the large-scale production of CPCs in an in vitro environment. This study aimed to use an effective culture system utilizing signaling factors for the large-scale expansion of hESC-derived CPCs with the potential to differentiate into functional cardiac lineage cells. METHODS AND RESULTS: Initially, CPCs were generated from hESCs using a 4-day differentiation protocol with a combination of four small molecules (CHIR99021, IWP2, SB-431542, and purmorphamine). These CPCs were then expanded and maintained in a medium containing three factors (bFGF, CHIR, and A83-01), resulting in a > 6,000-fold increase after 8 passages. These CPCs were successfully cryopreserved for an extended period in late passages. The expanded CPCs maintained their gene and protein expression signatures as well as their differentiation capacity through eight passages. Additionally, these CPCs could differentiate into four types of cardiac lineage cells: cardiomyocytes, endothelial cells, smooth muscle cells, and fibroblasts, demonstrating appropriate functionality. Furthermore, the coculture of these CPC-derived cardiovascular lineage cells in rat tail collagen resulted in cardiac microtissue formation, highlighting the potential of this 3D platform for studying cardiovascular physiology in vitro. CONCLUSION: In conclusion, expandable hESC-derived CPCs demonstrated the ability to self-renewal and differentiation into functional cardiovascular lineage cells consistently across passages, which may apply as potential cell sources for in vitro cardiovascular studies.

Correction: Firoozi et al. A Cell-Free SDKP-Conjugated Self-Assembling Peptide Hydrogel Sufficient for Improvement of Myocardial Infarction. Biomolecules 2020, 10, 205.

The authors wish to make the following corrections to this paper [...].