Cardiomyocyte differentiation of mesenchymal stem cells from bone marrow: new regulators and its implications

Optimizing Cardiomyocyte Differentiation: Comparative Analysis of Bone Marrow and Adipose-Derived Mesenchymal Stem Cells in Rats Using 5-Azacytidine and Low-Dose FGF and IGF Treatment

Mesenchymal stem cells (MSCs) exhibit multipotency, self-renewal, and immune-modulatory properties, making them promising in regenerative medicine, particularly in cardiovascular treatments. However, optimizing the MSC source and induction method of cardiac differentiation is challenging. This study compares the cardiomyogenic potential of bone marrow (BM)-MSCs and adipose-derived (AD)-MSCs using 5-Azacytidine (5-Aza) alone or combined with low doses of Fibroblast Growth Factor (FGF) and Insulin-like Growth Factor (IGF). BM-MSCs and AD-MSCs were differentiated using two protocols: 10 μmol 5-Aza alone and 10 μmol 5-Aza with 1 ng/mL FGF and 10 ng/mL IGF. Morphological, transcriptional, and translational analyses, along with cell viability assessments, were performed. Both the MSC types exhibited similar morphological changes; however, AD-MSCs achieved 70-80% confluence faster than BM-MSCs. Surface marker profiling confirmed CD29 and CD90 positivity and CD45 negativity. The differentiation protocols led to cell flattening and myotube formation, with earlier differentiation in AD-MSCs. The combined protocol reduced cell mortality in BM-MSCs and enhanced the expression of cardiac markers (MEF2c, Troponin I, GSK-3β), particularly in BM-MSCs. Immunofluorescence confirmed cardiac-specific protein expression in all the treated groups. Both MSC types exhibited the expression of cardiac-specific markers indicative of cardiomyogenic differentiation, with the combined treatment showing superior efficiency for BM-MSCs.

Differentiation of bone marrow mesenchymal stem cells into Leydig-like cells with testicular extract liquid in vitro

Differentiation of Leydig cells plays a key role in male reproductive function. Bone marrow mesenchymal stem cells (BMSCs) have emerged as a potential cell source for generating Leydig-like cells due to their multipotent differentiation capacity and accessibility. This study aimed to investigate the morphological and genetic expression changes of BMSCs during differentiation into Leydig-like cells. Testicular extract liquid, which simulates the microenvironment in vivo, induced the third passage BMSCs differentiated into Leydig-like cells. Changes in cell morphology were observed by microscopy, the formation of lipid droplets of androgen precursor was identified by Oil Red Staining, and the expression of testicular specific genes 3β-HSD and SF-1 in testicular stromal cells was detected by RT-qPCR. BMSCs isolated from the bone marrow of Sprague-Dawley (SD) rats were cultured for 3 generations and identified as qualified BMSCs in terms of morphology and cell surface markers. After 14 days of induction with testicular tissue lysate, lipid droplets appeared in the cytoplasm of P3 BMSCs by Oil Red O staining. RT-qPCR detection was performed on BMSCs on the 3rd, 7th, 14th, and 21st day after induction. Relative expression levels of 3β-HSD mRNA significantly increased after 14 days of induction, while the relative expression of SF-1 mRNA increased after 14 days of induction but was not significant. BMSCs can differentiate into testicular interstitial cells with reserve androgen precursor lipid droplets after induction by testicular tissue lysate. The differentiation ability of BMSCs provides the potential to reconstruct the testicular microenvironment and is expected to fundamentally improve testicular function and provide new treatment options for abnormal spermatogenesis diseases.

Research hotspots and emerging trends of mesenchymal stem cells in cardiovascular diseases: a bibliometric-based visual analysis

Background

Mesenchymal stem cells (MSCs) have important research value and broad application prospects in cardiovascular diseases (CVDs). However, few bibliometric analyses on MSCs in cardiovascular diseases are available. This study aims to provide a thorough review of the cooperation and influence of countries, institutions, authors, and journals in the field of MSCs in cardiovascular diseases, with the provision of discoveries in the latest progress, evolution paths, frontier research hotspots, and future research trends in the regarding field.

Methods

The articles related to MSCs in cardiovascular diseases were retrieved from the Web of Science. The bibliometric study was performed by CiteSpace and VOSviewer, and the knowledge map was generated based on data obtained from retrieved articles.

Results

In our study, a total of 4,852 publications launched before August 31, 2023 were accessed through the Web of Science Core Collection (WoSCC) database via our searching strategy. Significant fluctuations in global publications were observed in the field of MSCs in CVDs. China emerged as the nation with the largest number of publications, yet a shortage of high-quality articles was noted. The interplay among countries, institutions, journals and authors is visually represented in the enclosed figures. Importantly, current research trends and hotspots are elucidated. Cluster analysis on references has highlighted the considerable interest in exosomes, extracellular vesicles, and microvesicles. Besides, keywords analysis revealed a strong emphasis on myocardial infarction, therapy, and transplantation. Treatment methods-related keywords were prominent, while keywords associated with extracellular vesicles gathered significant attention from the long-term perspective.

Conclusion

MSCs in CVDs have become a topic of active research interest, showcasing its latent value and potential. By summarizing the latest progress, identifying the research hotspots, and discussing the future trends in the advancement of MSCs in CVDs, we aim to offer valuable insights for considering research prospects.

Dental pulp stem cells ameliorate D-galactose-induced cardiac ageing in rats

Background

Ageing is a key risk factor for cardiovascular disease and is linked to several alterations in cardiac structure and function, including left ventricular hypertrophy and increased cardiomyocyte volume, as well as a decline in the number of cardiomyocytes and ventricular dysfunction, emphasizing the pathological impacts of cardiomyocyte ageing. Dental pulp stem cells (DPSCs) are promising as a cellular therapeutic source due to their minimally invasive surgical approach and remarkable proliferative ability.

Aim

This study is the first to investigate the outcomes of the systemic transplantation of DPSCs in a D-galactose (D-gal)-induced rat model of cardiac ageing. Methods. Thirty 9-week-old Sprague-Dawley male rats were randomly assigned into three groups: control, ageing (D-gal), and transplanted groups (D-gal + DPSCs). D-gal (300 mg/kg/day) was administered intraperitoneally daily for 8 weeks. The rats in the transplantation group were intravenously injected with DPSCs at a dose of 1 × 106 once every 2 weeks.

Results

The transplanted cells migrated to the heart, differentiated into cardiomyocytes, improved cardiac function, upregulated Sirt1 expression, exerted antioxidative effects, modulated connexin-43 expression, attenuated cardiac histopathological alterations, and had anti-senescent and anti-apoptotic effects.

Conclusion

Our results reveal the beneficial effects of DPSC transplantation in a cardiac ageing rat model, suggesting their potential as a viable cell therapy for ageing hearts.

Addressing Cardiovascular Toxicity Risk of Electronic Nicotine Delivery Systems in the Twenty-First Century: "What Are the Tools Needed for the Job?" and "Do We Have Them?"

Cigarette smoking is positively and robustly associated with cardiovascular disease (CVD), including hypertension, atherosclerosis, cardiac arrhythmias, stroke, thromboembolism, myocardial infarctions, and heart failure. However, after more than a decade of ENDS presence in the U.S. marketplace, uncertainty persists regarding the long-term health consequences of ENDS use for CVD. New approach methods (NAMs) in the field of toxicology are being developed to enhance rapid prediction of human health hazards. Recent technical advances can now consider impact of biological factors such as sex and race/ethnicity, permitting application of NAMs findings to health equity and environmental justice issues. This has been the case for hazard assessments of drugs and environmental chemicals in areas such as cardiovascular, respiratory, and developmental toxicity. Despite these advances, a shortage of widely accepted methodologies to predict the impact of ENDS use on human health slows the application of regulatory oversight and the protection of public health. Minimizing the time between the emergence of risk (e.g., ENDS use) and the administration of well-founded regulatory policy requires thoughtful consideration of the currently available sources of data, their applicability to the prediction of health outcomes, and whether these available data streams are enough to support an actionable decision. This challenge forms the basis of this white paper on how best to reveal potential toxicities of ENDS use in the human cardiovascular system-a primary target of conventional tobacco smoking. We identify current approaches used to evaluate the impacts of tobacco on cardiovascular health, in particular emerging techniques that replace, reduce, and refine slower and more costly animal models with NAMs platforms that can be applied to tobacco regulatory science. The limitations of these emerging platforms are addressed, and systems biology approaches to close the knowledge gap between traditional models and NAMs are proposed. It is hoped that these suggestions and their adoption within the greater scientific community will result in fresh data streams that will support and enhance the scientific evaluation and subsequent decision-making of tobacco regulatory agencies worldwide.

Uncovering the link between diabetes and cardiovascular diseases: insights from adipose-derived stem cells

Cardiovascular diseases (CVDs) are the leading causes of morbidity and mortality worldwide. The escalating global occurrence of obesity and diabetes mellitus (DM) has led to a significant upsurge in individuals afflicted with CVDs. As the prevalence of CVDs continues to rise, it is becoming increasingly important to identify the underlying cellular and molecular mechanisms that contribute to their development and progression, which will help discover novel therapeutic avenues. Adipose tissue (AT) is a connective tissue that plays a crucial role in maintaining lipid and glucose homeostasis. However, when AT is exposed to diseased conditions, such as DM, this tissue will alter its phenotype to become dysfunctional. AT is now recognized as a critical contributor to CVDs, especially in patients with DM. AT is comprised of a heterogeneous cellular population, which includes adipose-derived stem cells (ADSCs). ADSCs resident in AT are believed to regulate physiological cardiac function and have potential cardioprotective roles. However, recent studies have also shown that ADSCs from various adipose tissue depots become pro-apoptotic, pro-inflammatory, less angiogenic, and lose their ability to differentiate into various cell lineages upon exposure to diabetic conditions. This review aims to summarize the current understanding of the physiological roles of ADSCs, the impact of DM on ADSC phenotypic changes, and how these alterations may contribute to the pathogenesis of CVDs.

Detailed role of mesenchymal stem cell (MSC)-derived exosome therapy in cardiac diseases

Coronary heart disease (CHD) continues to be the leading cause of morbidity and mortality. There are numerous therapeutic reperfusion methods, including thrombolytic therapy, primary percutaneous coronary intervention, and anti-remodeling drugs like angiotensin-converting enzyme inhibitors and beta-blockers. Despite this, there is no pharmacological treatment that can effectively stop cardiomyocyte death brought on by myocardial ischemia/reperfusion (I/R) injury. For the purpose of regenerating cardiac tissue, mesenchymal stem cell (MSC) therapy has recently gained more attention. The pleiotropic effects of MSCs are instead arbitrated by the secretion of soluble paracrine factors and are unrelated to their capacity for differentiation. One of these paracrine mediators is the extracellular vesicle known as an exosome. Exosomes deliver useful cargo to recipient cells from MSCs, including peptides, proteins, cytokines, lipids, miRNA, and mRNA molecules. Exosomes take part in intercellular communication processes and help tissues and organs that have been injured or are ill heal. Exosomes alone were found to be the cause of MSCs' therapeutic effects in a variety of animal models, according to studies. Here, we have focused on the recent development in the therapeutic capabilities of exosomal MSCs in cardiac diseases.

A genome-wide CRISPR screen identifies BRD4 as a regulator of cardiomyocyte differentiation

Human induced pluripotent stem cell (hiPSC) to cardiomyocyte (CM) differentiation has reshaped approaches to studying cardiac development and disease. In this study, we employed a genome-wide CRISPR screen in a hiPSC to CM differentiation system and reveal here that BRD4, a member of the bromodomain and extraterminal (BET) family, regulates CM differentiation. Chemical inhibition of BET proteins in mouse embryonic stem cell (mESC)-derived or hiPSC-derived cardiac progenitor cells (CPCs) results in decreased CM differentiation and persistence of cells expressing progenitor markers. In vivo, BRD4 deletion in second heart field (SHF) CPCs results in embryonic or early postnatal lethality, with mutants demonstrating myocardial hypoplasia and an increase in CPCs. Single-cell transcriptomics identified a subpopulation of SHF CPCs that is sensitive to BRD4 loss and associated with attenuated CM lineage-specific gene programs. These results highlight a previously unrecognized role for BRD4 in CM fate determination during development and a heterogenous requirement for BRD4 among SHF CPCs.

Stem Cell-Based Therapy and Cell-Free Therapy as an Alternative Approach for Cardiac Regeneration

The World Health Organization reports that cardiovascular diseases (CVDs) represent 32% of all global deaths. The ineffectiveness of conventional therapies in CVDs encourages the development of novel, minimally invasive therapeutic strategies for the healing and regeneration of damaged tissue. The self-renewal capacity, multilineage differentiation, lack of immunogenicity, and immunosuppressive properties of mesenchymal stem cells (MSCs) make them a promising option for CVDs. However, growing evidence suggests that myocardial regeneration occurs through paracrine factors and extracellular vesicle (EV) secretion, rather than through differentiation into cardiomyocytes. Research shows that stem cells secrete or surface-shed into their culture media various cytokines, chemokines, growth factors, anti-inflammatory factors, and EVs, which constitute an MSC-conditioned medium (MSC-CM) or the secretome. The use of MSC-CM enhances cardiac repair through resident heart cell differentiation, proliferation, scar mass reduction, a decrease in infarct wall thickness, and cardiac function improvement comparable to MSCs without their side effects. This review highlights the limitations and benefits of therapies based on stem cells and their secretome as an innovative treatment of CVDs.

Unveiling Mesenchymal Stem Cells' Regenerative Potential in Clinical Applications: Insights in miRNA and lncRNA Implications

It is now widely recognized that mesenchymal stem cells (MSCs) possess the capacity to differentiate into a wide array of cell types. Numerous studies have identified the role of lncRNA in the regulation of MSC differentiation. It is important to elucidate the role and interplay of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in the regulation of signalling pathways that govern MSC function. Furthermore, miRNAs and lncRNAs are important clinical for innovative strategies aimed at addressing a wide spectrum of existing and emerging disease. Hence it is important to consider their impact on MSC function and differentiation. Examining the data available in public databases, we have collected the literature containing the latest discoveries pertaining to human stem cells and their potential in both fundamental research and clinical applications. Furthermore, we have compiled completed clinical studies that revolve around the application of MSCs, shedding light on the opportunities presented by harnessing the regulatory potential of miRNAs and lncRNAs. This exploration of the therapeutic possibilities offered by miRNAs and lncRNAs within MSCs unveils exciting prospects for the development of precision therapies and personalized treatment approaches. Ultimately, these advancements promise to augment the efficacy of regenerative strategies and produce positive outcomes for patients. As research in this field continues to evolve, it is imperative to explore and exploit the vast potential of miRNAs and lncRNAs as therapeutic agents. The findings provide a solid basis for ongoing investigations, fuelling the quest to fully unlock the regenerative potential of MSCs.

Ascorbic acid and salvianolic acid B enhance the valproic acid and 5-azacytidinemediated cardiac differentiation of mesenchymal stem cells

BACKGROUND

Cardiovascular diseases remain a major cause of death globally. Cardiac cells once damaged, cannot resume the normal functioning of the heart. Bone marrow derived mesenchymal stem cells (BM-MSCs) have shown the potential to differentiate into cardiac cells. Epigenetic modifications determine cell identity during embryo development via regulation of tissue specific gene expression. The major epigenetic mechanisms that control cell fate and biological functions are DNA methylation and histone modifications. However, epigenetic modifiers alone are not sufficient to generate mature cardiac cells. Various small molecules such as ascorbic acid (AA) and salvianolic acid B (SA) are known for their cardiomyogenic potential. Therefore, this study is aimed to examine the synergistic effects of epigenetic modifiers, valproic acid (VPA) and 5-azacytidine (5-aza) with cardiomyogenic molecules, AA and SA in the cardiac differentiation of MSCs.

METHODS AND RESULTS

BM-MSCs were isolated, propagated, characterized, and then treated with an optimized dose of VPA or 5-aza for 24 h. MSCs were maintained in a medium containing AA and SA for 21 days. All groups were assessed for the expression of cardiac genes and proteins through q-PCR and immunocytochemistry, respectively. Results show that epigenetic modifiers VPA or 5-aza in combination with AA and SA significantly upregulate the expression of cardiac genes MEF2C, Nkx2.5, cMHC, Tbx20, and GATA-4. In addition, VPA or 5-aza pretreatment along with AA and SA enhanced the expression of the cardiac proteins connexin-43, GATA-4, cTnI, and Nkx2.5.

CONCLUSION

These findings suggest that epigenetic modifiers valproic acid and 5-azacytidine in combination with ascorbic acid and salvianolic acid B promote cardiac differentiation of MSCs. This pretreatment strategy can be exploited for designing future stem cell based therapeutic strategies for cardiovascular diseases.

Gene Therapy Based on Mesenchymal Stem Cells Derived from Adipose Tissue for the Treatment of Obesity and Its Metabolic Complications

Obesity is a highly prevalent condition often associated with dysfunctional adipose tissue. Stem cell-based therapies have become a promising tool for therapeutic intervention in the context of regenerative medicine. Among all stem cells, adipose-derived mesenchymal stem cells (ADMSCs) are the most easily obtained, have immunomodulatory properties, show great ex vivo expansion capacity and differentiation to other cell types, and release a wide variety of angiogenic factors and bioactive molecules, such as growth factors and adipokines. However, despite the positive results obtained in some pre-clinical studies, the actual clinical efficacy of ADMSCs still remains controversial. Transplanted ADMSCs present a meager rate of survival and proliferation, possibly because of the damaged microenvironment of the affected tissues. Therefore, there is a need for novel approaches to generate more functional ADMSCs with enhanced therapeutic potential. In this context, genetic manipulation has emerged as a promising strategy. In the current review, we aim to summarize several adipose-focused treatments of obesity, including cell therapy and gene therapy. Particular emphasis will be given to the continuum from obesity to metabolic syndrome, diabetes, and underlying non-alcoholic fatty liver disease (NAFLD). Furthermore, we will provide insights into the potential shared adipocentric mechanisms involved in these pathophysiological processes and their remediation using ADMSCs.

Ischemia challenged epicardial adipose tissue stem cells-derived extracellular vesicles alter the gene expression of cardiac fibroblasts to cardiomyocyte like phenotype

The present study hypothesizes that the ischemic insults activate epicardial adipose tissue-derived stem cells (EATDS) to secrete extracellular vesicles (EVs) packed with regenerative mediators to alter the gene expression in cardiac fibroblasts (CF). EATDS and CF were isolated from hyperlipidemic microswine and EVs were harvested from control, simulated ischemia (ISC) and ischemia-reperfusion (ISC/R) groups. The in vitro interaction between ISC-EVs and CF resulted in the upregulation of cardiomyocyte-specific transcription factors including GATA4, Nkx2.5, IRX4, and TBX5 in CF and the healing marker αSMA and the downregulation of fibroblast biomarkers such as vimentin, FSP1, and podoplanin and the cardiac biomarkers such as troponin-I and connexin-43. These results suggest a cardiomyocyte-like phenotype as confirmed by immunostaining and Western blot. The LC-MS/MS analysis of ISC-EVs LGALS1, PRDX2, and CCL2 to be the potent protein mediators which are intimately involved in versatile regenerative processes and connected with a diverse array of regenerative genes. Moreover, the LGALS1+, PRDX2+, and CCL2+ EATDS phenotypes were deciphered at single cell resolution revealing corresponding sub-populations with superior healing potential. Overall, the findings unveiled the healing potential of EATDS-derived EVs and sub-populations of regenerative EATDS promising novel translational opportunities in improved cardiac healing following ischemic injury.

MicroRNAs as a Novel Player for Differentiation of Mesenchymal Stem Cells into Cardiomyocytes

Cardiovascular disease (CVD) is defined as a class of disorders affecting the heart and blood vessels. Cardiomyocytes and endothelial cells play important roles in cardiac regeneration and heart repair. However, the proliferating capacity of cardiomyocytes is limited. To overcome this issue, mesenchymal stem cells (MSCs) have emerged as an alternative strategy for CVD therapy. MSCs can proliferate and differentiate (or trans-differentiate) into cardiomyocytes. Several in vitro and in vivo differentiation protocols have been used to obtain MSCs-derived cardiomyocytes. It was recently investigated that microRNAs (miRNAs) by targeting several signaling pathways, including STAT3, Wnt/β-catenin, Notch, and TBX5, play a crucial role in regulating cardiomyocytes' differentiation of MSCs. In this review, we focused on the role of miRNAs in the differentiation of MSCs into cardiomyocytes.

Direct Cardiac Reprogramming: Current Status and Future Prospects

Advances in cellular reprogramming articulated the path for direct cardiac lineage conversion, bypassing the pluripotent state. Direct cardiac reprogramming attracts major attention because of the low or nil regenerative ability of cardiomyocytes, resulting in permanent cell loss in various heart diseases. In the field of cardiology, balancing this loss of cardiomyocytes was highly challenging, even in the modern medical world. Soon after the discovery of cell reprogramming, direct cardiac reprogramming also became a promising alternative for heart regeneration. This review mainly focused on the various direct cardiac reprogramming approaches (integrative and non-integrative) for the derivation of induced autologous cardiomyocytes. It also explains the advancements in cardiac reprogramming over the decade with the pros and cons of each approach. Further, the review highlights the importance of clinically relevant (non-integrative) approaches and their challenges for the prospective applications for personalized medicine. Apart from direct cardiac reprogramming, it also discusses the other strategies for generating cardiomyocytes from different sources. The understanding of these strategies could pave the way for the efficient generation of integration-free functional autologous cardiomyocytes through direct cardiac reprogramming for various biomedical applications.

An efficient human stem cells derived cardiotoxicity testing platform for testing oncotherapeutic analogues of quercetin and cinnamic acid

Oncotherapeutics research is progressing at a rapid pace, however, not many drugs complete the successful clinical trial because of severe off-target toxicity to cardiomyocytes which ultimately leads to cardiac dysfunction. It is thus important to emphasize the need for early testing for possible cardiotoxicity of emerging oncotherapeutics. In this study, we assessed a novel stem cell-derived cardiac model for testing for cardiotoxicity of novel oncotherapeutics. We evaluated the cardiotoxic effect of synthesized derivatives of oncotherapeutics, quercetin (QMJ-2, -5, and -6) and cinnamic acid (NMJ-1, -2, and -3) using human Wharton's jelly mesenchymal stem cells-derived cardiomyocytes (WJCM) against known cardiotoxic oncologic drugs, doxorubicin, 5-fluorouracil, cisplatin. QMJ-6, NMJ-2, and NMJ-3 were not cardiotoxic and had minimum cardiac side effects. They did not show any effect on cardiomyocyte viability, caused low LDH release, and intracellular ROS production kept the calcium flux minimal and protected the active mitochondrial status in cardiomyocytes. They persevered cardiac-specific gene expression as well. However, compounds QMJ-2, QMJ-5, and NMJ-1 were cardiotoxic and the concentration needs to be reduced to prevent toxic effects on cardiomyocytes. Significantly, we were able to demonstrate that WJCM is an efficient cardiac testing model to analyze the cardiotoxicity of drugs in a human context.

Experimental study on co-culture of DiI-labeled rat bone marrow mesenchymal stem cells and neonatal rat cardiomyocytes to induce differentiation into cardiomyocyte-like cells

BACKGROUND: Myocardial infarction is a serious clinical disease with high mortality and poor prognosis. Cardiomyocytes (CMs) have limited regeneration abilities after ischemic injury. Their growth and differentiation can be enhanced by contact co-culture with stem cells. OBJECTIVE: The aim was to study the contact co-culture of Dil-labeled bone marrow mesenchymal stem cells (BMSCs) and CMs for inducing differentiation of CMs from stem cells for treating myocardial infarction. METHODS: After contact co-culture, the differentiation of BMSCs into CMs was analyzed qualitatively by detecting myocardial markers (cardiac troponin T and α-smooth muscle actin) using immunofluorescence and quantitatively using flow cytometry. To examine the mechanism, possible gap junctions between BMSCs and CMs were analyzed by detecting gap junction protein connexin 43 (C×43) expression in BMSCs using immunofluorescence. The functionality of gap junctions was analyzed using dye transfer experiments. RESULTS: The results revealed that BMSCs in contact with CMs exhibited myocardial markers and a significant increase in differentiation rate (P < 0.05); they also proved the existence and function of gap junctions between BMSCs and CMs. CONCLUSIONS: It was shown that contact co-culture can induce Dil-labeled BMSCs to differentiate into CM-like cells and examined the principle of gap junction-mediated signaling pathways involved in inducing stem cells to differentiate into cardiomyocytes.

Stem Cells and Organs-on-chips: New Promising Technologies for Human Infertility Treatment

Having biological children remains an unattainable dream for most couples with reproductive failure or gonadal dysgenesis. The combination of stem cells with gene editing technology and organ-on-a-chip models provides a unique opportunity for infertile patients with impaired gametogenesis caused by congenital disorders in sex development or cancer survivors. But how will these technologies overcome human infertility? This review discusses the regenerative mechanisms, applications, and advantages of different types of stem cells for restoring gametogenesis in infertile patients, as well as major challenges that must be overcome before clinical application. The importance and limitations of in vitro generation of gametes from patient-specific human-induced pluripotent stem cells (hiPSCs) will be discussed in the context of human reproduction. The potential role of organ-on-a-chip models that can direct differentiation of hiPSC-derived primordial germ cell-like cells to gametes and other reproductive organoids is also explored. These rapidly evolving technologies provide prospects for improving fertility to individuals and couples who experience reproductive failure.

Myocardial infarction from a tissue engineering and regenerative medicine point of view: A comprehensive review on models and treatments

In the modern world, myocardial infarction is one of the most common cardiovascular diseases, which are responsible for around 18 million deaths every year or almost 32% of all deaths. Due to the detrimental effects of COVID-19 on the cardiovascular system, this rate is expected to increase in the coming years. Although there has been some progress in myocardial infarction treatment, translating pre-clinical findings to the clinic remains a major challenge. One reason for this is the lack of reliable and human representative healthy and fibrotic cardiac tissue models that can be used to understand the fundamentals of ischemic/reperfusion injury caused by myocardial infarction and to test new drugs and therapeutic strategies. In this review, we first present an overview of the anatomy of the heart and the pathophysiology of myocardial infarction, and then discuss the recent developments on pre-clinical infarct models, focusing mainly on the engineered three-dimensional cardiac ischemic/reperfusion injury and fibrosis models developed using different engineering methods such as organoids, microfluidic devices, and bioprinted constructs. We also present the benefits and limitations of emerging and promising regenerative therapy treatments for myocardial infarction such as cell therapies, extracellular vesicles, and cardiac patches. This review aims to overview recent advances in three-dimensional engineered infarct models and current regenerative therapeutic options, which can be used as a guide for developing new models and treatment strategies.

Combination of mesenchymal stem cells and three-dimensional collagen scaffold preserves ventricular remodeling in rat myocardial infarction model

BACKGROUND

Cardiovascular diseases are the major cause of mortality worldwide. Regeneration of the damaged myocardium remains a challenge due to mechanical constraints and limited healing ability of the adult heart tissue. Cardiac tissue engineering using biomaterial scaffolds combined with stem cells and bioactive molecules could be a highly promising approach for cardiac repair. Use of biomaterials can provide suitable microenvironment to the cells and can solve cell engraftment problems associated with cell transplantation alone. Mesenchymal stem cells (MSCs) are potential candidates in cardiac tissue engineering because of their multilineage differentiation potential and ease of isolation. Use of DNA methyl transferase inhibitor, such as zebularine, in combination with three-dimensional (3D) scaffold can promote efficient MSC differentiation into cardiac lineage, as epigenetic modifications play a fundamental role in determining cell fate and lineage specific gene expression.

AIM

To investigate the role of collagen scaffold and zebularine in the differentiation of rat bone marrow (BM)-MSCs and their subsequent in vivo effects.

METHODS

MSCs were isolated from rat BM and characterized morphologically, immunophenotypically and by multilineage differentiation potential. MSCs were seeded in collagen scaffold and treated with 3 μmol/L zebularine in three different ways. Cytotoxicity analysis was done and cardiac differentiation was analyzed at the gene and protein levels. Treated and untreated MSC-seeded scaffolds were transplanted in the rat myocardial infarction (MI) model and cardiac function was assessed by echocardiography. Cell tracking was performed by DiI dye labeling, while regeneration and neovascularization were evaluated by histological and immunohistochemical analysis, respectively.

RESULTS

MSCs were successfully isolated and seeded in collagen scaffold. Cytotoxicity analysis revealed that zebularine was not cytotoxic in any of the treatment groups. Cardiac differentiation analysis showed more pronounced results in the type 3 treatment group which was subsequently chosen for the transplantation in the in vivo MI model. Significant improvement in cardiac function was observed in the zebularine treated MSC-seeded scaffold group as compared to the MI control. Histological analysis also showed reduction in fibrotic scar, improvement in left ventricular wall thickness and preservation of ventricular remodeling in the zebularine treated MSC-seeded scaffold group. Immunohistochemical analysis revealed significant expression of cardiac proteins in DiI labeled transplanted cells and a significant increase in the number of blood vessels in the zebularine treated MSC-seeded collagen scaffold transplanted group.

CONCLUSION

Combination of 3D collagen scaffold and zebularine treatment enhances cardiac differentiation potential of MSCs, improves cell engraftment at the infarcted region, reduces infarct size and improves cardiac function.

Histone demethylase KDM5B catalyzed H3K4me3 demethylation to promote differentiation of bone marrow mesenchymal stem cells into cardiomyocytes

Background

Studies have shown that histone H3 methylation is involved in regulating the differentiation of Bone Marrow Mesenchymal Stem Cells (BMSCs). KDM5B can specifically reduce the level of histone 3 lysine 4 trimethylation (H3K4me3), thereby activating the expression of related genes and participating in biological processes such as cell differentiation, embryonic development and tumor formation. Whether KDM5B is involved in the regulation of BMSCs differentiation into cardiomyocytes through the above manner has not been reported.

Objective

To investigate the effect of KDM5B on the induction and differentiation of swine BMSCs into myocardial cells in vitro.

Methods

Swine bone marrow BMSCs were isolated and cultured, and the overexpression, interference expression and blank vector of KMD5B were constructed and transfected by lentivirus. BMSCs was induced to differentiate into cardiomyocytes by 5-azacytidine (5-AZA) in vitro, and the differentiation efficiency was compared by immunofluorescence, RT-PCR, Western Blot and whole-cell patch clamp detection.

Result

Compared with the control group, the expression levels of histone H3K4me3 and pluripotency gene Nanog in KDM5B overexpression group were significantly decreased, while the expression level of key myocardial gene HCN4 and myocardial marker gene α-Actin and cTNT were significantly increased, and the Na⁺ current density on the surface of differentiated myocardial cell membrane was significantly increased. Meanwhile, the corresponding results of the KDM5B silent expression group were just opposite.

Conclusions

It indicated that enhanced KDM5B expression could promote the differentiation of BMSCs into cardiomyocytes and improve the differentiation efficiency by controlling H3K4 methylation levels.

Effect of miR-34a on the Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells (BMSCs) in Hyperlipidemia Rats

This study intends to explore miR-34a’s effect on BMSCs osteogenic differentiation of hyperlipidemia. 20 SD rats were equally assigned into control group (normal diet) and high-fat group (research diet). Cells were transfected with miR-34a mimic or negative control followed by meausring miR-34a, Dvl2, PPAR-γ, ALP, Runx2, and sp7, and ALP activity. The number of mineralized nodules, adipocytes, miR-34a and PPAR-γ expression in high-fat group were significantly increased and Dvl2, ALP, Runx2, and sp7 mRNA showed opposite profiles. Meanwhile, Runx2, ALP protein, cytoplasm and nuclear blue-black particles, Dvl2 protein and mRNA in miR-34a mimic group were significantly downregulated (P < 0.05). Additionally, the luciferase activity of wild-type plasmid+miR-34a mimic group was significantly lower than mutant group, indicating that miR-34a targets Dvl2. In conclusion, miR-34a inhibits the osteogenic differentiation of hyperlipidemia BMSCs by inhibiting the expression of Dvl2, Runx2 and ALP activity, indicating that it might be target in the hyperlipidemia treatment.

Preparation of myocardial patches from DiI-labeled rat bone marrow mesenchymal stem cells and neonatal rat cardiomyocytes contact co-cultured on polycaprolactone film

DiI-labeled BMSCs were contact co-cultured with CMs on PCL film to prepare myocardial patches. BMSCs were labeled with DiI dye. DiI-labeled BMSCs were co-cultured with CMs on PCL film in the experimental group, while CMs were replaced with the same amount of unlabeled BMSCs in the control group. After 24 h, cell growth was observed by light microscopy and cells were fixed for scanning electron microscopy. After 7 days of co-culture, cells were stained for immunofluorescence detection of myocardial markers cardiac troponin T (cTnT) and α-actin. Differentiation of BMSCs on PCL was observed by fluorescence microscopy. The efficiency of BMSC differentiation into CMs was analyzed by flow cytometry on the first and seventh days of co-culture. CMs were stained with calcein alone and contact co-cultured with DiI-labeled BMSCs on PCL film to observe intercellular dye transfer. Finally, cells were stained for immunofluorescence detection of connexin 43 (Cx43) expression and to observe the relationship between gap junctions and contact co-culture. After co-culture for 24 h, cells were observed to have attached to PCL by light microscopy. Upon appropriate excitation, DiI-labeled BMSCs exhibited red fluorescence, while unlabeled CMs did not. Scanning electron microscopy revealed a large number of cells on the PCL membrane and their cell state appeared normal. On the seventh day, some DiI-labeled BMSCs expressed cTnT and α-actin. Flow cytometry showed that the rate of stem cell differentiation in the experimental group was significantly higher than the control group on the seven day (20.12% > 3.49%, P < 0.05). From the second day of co-culture, immunofluorescence staining for Cx43 revealed green fluorescent puncta in some BMSCs; from the third day of co-culture, a portion of BMSCs exhibited green fluorescence in dye transfer tests. Contact co-culture of DiI-labeled BMSCs and CMs on PCL film successfully generated myocardial patches.

A porcine cholecystic extracellular matrix conductive scaffold for cardiac tissue repair

Cardiac tissue engineering using cells, scaffolds or signaling molecules is a promising approach for replacement or repair of damaged myocardium. This study addressed the contemporary need for a conductive biomimetic nanocomposite scaffold for cardiac tissue engineering by examining the use of a gold nanoparticle-incorporated porcine cholecystic extracellular matrix for the same. The scaffold had an electrical conductivity (0.74 ± 0.03 S/m) within the range of native myocardium. It was a suitable substrate for the growth and differentiation of cardiomyoblast (H9c2) as well as rat mesenchymal stem cells to cardiomyocyte-like cells. Moreover, as an epicardial patch, the scaffold promoted neovascularisation and cell proliferation in infarcted myocardium of rats. It was concluded that the gold nanoparticle coated cholecystic extracellular matrix is a prospective biomaterial for cardiac tissue engineering.

Dissolvable microgel-templated macroporous hydrogels for controlled cell assembly

Mesenchymal stem cells (MSCs)-based therapies have been widely used to promote tissue regeneration and to modulate immune/inflammatory response. The therapeutic potential of MSCs can be further improved by forming multi-cellular spheroids. Meanwhile, hydrogels with macroporous structures are advantageous for improving mass transport properties for the cell-laden matrices. Herein, we report the fabrication of MSC-laden macroporous hydrogel scaffolds through incorporating rapidly dissolvable spherical cell-laden microgels. Dissolvable microgels were fabricated by tandem droplet-microfluidics and thiol-norbornene photopolymerization using a novel fast-degrading macromer poly(ethylene glycol)-norbornene-dopamine (PEGNB-Dopa). The cell-laden PEGNB-Dopa microgels were subsequently encapsulated within another bulk hydrogel matrix, whose porous structure was generated efficiently by the rapid degradation of the PEGNB-Dopa microgels. The cytocompatibility of this in situ pore-forming approach was demonstrated with multiple cell types. Furthermore, adjusting the stiffness and cell adhesiveness of the bulk hydrogels afforded the formation of solid cell spheroids or hollow spheres. The assembly of solid or hollow MSC spheroids led to differential activation of AKT pathway. Finally, MSCs solid spheroids formed in situ within the macroporous hydrogels exhibited robust secretion of HGF, VEGF-A, IL-6, IL-8, and TIMP-2. In summary, this platform provides an innovative method for forming cell-laden macroporous hydrogels for a variety of future biomedical applications.

Cardiac regeneration following myocardial infarction: the need for regeneration and a review of cardiac stromal cell populations used for transplantation

Myocardial infarction is a leading cause of death globally due to the inability of the adult human heart to regenerate after injury. Cell therapy using cardiac-derived progenitor populations emerged about two decades ago with the aim of replacing cells lost after ischaemic injury. Despite early promise from rodent studies, administration of these populations has not translated to the clinic. We will discuss the need for cardiac regeneration and review the debate surrounding how cardiac progenitor populations exert a therapeutic effect following transplantation into the heart, including their ability to form de novo cardiomyocytes and the release of paracrine factors. We will also discuss limitations hindering the cell therapy field, which include the challenges of performing cell-based clinical trials and the low retention of administered cells, and how future research may overcome them.

Emerging Trends in Mesenchymal Stem Cells Applications for Cardiac Regenerative Therapy: Current Status and Advances

Irreversible myocardium infarction is one of the leading causes of cardiovascular disease (CVD) related death and its quantum is expected to grow in coming years. Pharmacological intervention has been at the forefront to ameliorate injury-related morbidity and mortality. However, its outcomes are highly skewed. As an alternative, stem cell-based tissue engineering/regenerative medicine has been explored quite extensively to regenerate the damaged myocardium. The therapeutic modality that has been most widely studied both preclinically and clinically is based on adult multipotent mesenchymal stem cells (MSC) delivered to the injured heart. However, there is debate over the mechanistic therapeutic role of MSC in generating functional beating cardiomyocytes. This review intends to emphasize the role and use of MSC in cardiac regenerative therapy (CRT). We have elucidated in detail, the various aspects related to the history and progress of MSC use in cardiac tissue engineering and its multiple strategies to drive cardiomyogenesis. We have further discussed with a focus on the various therapeutic mechanism uncovered in recent times that has a significant role in ameliorating heart-related problems. We reviewed recent and advanced technologies using MSC to develop/create tissue construct for use in cardiac regenerative therapy. Finally, we have provided the latest update on the usage of MSC in clinical trials and discussed the outcome of such studies in realizing the full potential of MSC use in clinical management of cardiac injury as a cellular therapy module.

Peptide hormone ELABELA promotes rat bone marrow-derived mesenchymal stem cell proliferation and migration by manipulating the cell cycle through the PI3K/AKT pathway under the hypoxia and ischemia microenvironmemt

BACKGROUND

Mesenchymal stem cells (MSCs) are emerging as a potential candidate for stem cell transplantation to repair myocardial tissue in myocardial infarctions (MI). However, there are some pivotal limitations such as poor survival and low migration capacity of MSCs in hypoxic and ischemic microenvironments of MI. Our previous work verified that ELABELA (also abbreviated as ELA), a peptide hormone, could play a role as a growth factor and prolong the life span of rat bone marrow-derived mesenchymal stem cells (RAT BM-MSCs) under hypoxic and ischemic conditions. Nevertheless, the influence of ELA on the cell cycle, proliferation, and migration remains elusive. This study will further explore the improvement of the biological functions of ELA-treated RAT BM-MSCs, so as to provide a reference for improving the efficacy of RAT BM-MSCs in MI.

METHODS

Rat BM-MSCs were isolated from 80 to 120 g Sprague Dawley rats by flushing femurs and tibias under the aseptic condition. RAT BM-MSCs of the third passage were divided into control group, hypoxic/ischemic (H/I) group, ELA group, ELA-LY group and LY group. RAT BM-MSCs were cultured under normoxia in control group. In H/I group, RAT BM-MSCs were exposed to hypoxia (1% O2) and serum deprivation for 24 h. RAT BM-MSCs in ELA group were treated with 5 µM ELA prior to the H/I exposure for 24 h. The PI3K/AKT inhibitor, LY294002 (50 µM), was used in ELA-LY group and LY group to observe the effect of ELA on PI3K/AKT activation. Cell proliferation ability was examined by CCK-8. Cell cycle was assessed with flow cytometry. Cell migration was evaluated by Transwell assay. Expression levels of total-AKT, phosphorylated-AKT, and cell cycle-associated proteins were examined by Western blotting.

RESULTS

ELA-treated RAT BM-MSCs exhibited significantly higher proliferation ability, cell viability, and migration under H/I conditions. The cell cycle analysis showed that an increased proportion of cells in the S and G2/M phases of the cell cycle were observed in ELA-treated RAT BM-MSCs. The addition of ELA activated the PI3K/AKT signaling pathway. Additionally, upon treating with the inhibitor of the PI3K/AKT signaling pathway, ELA-triggered proliferation, cell viability, and migration were abrogated.

CONCLUSIONS

ELA can be used to enhance the proliferation ability, cell viability, and migration of RAT BM-MSCs through the PI3K/AKT signaling pathway and alleviate cell cycle arrest at the G0/G1 phase under hypoxic and ischemic injury. Thus, this study provides a promising strategy that ELA may help to optimize the mesenchymal stem cell-based therapy in MI.

Experimental study on co-culture of DiI labeled rat bone marrow mesenchymal stem cells and polycaprolactone film in vitro to make a cell patch

BACKGROUND

In stem cell therapy, due to the lack of an effective carrier, a large number of transplanted stem cells are lost and die. Therefore, finding a suitable carrier has become a further direction of stem cell therapy.

OBJECTIVE

In research on the co-culture of polycaprolactone (PCL) with 1,1'-Dioctadecyl-3,3,3',3'- tetramethylindocarbocyanine perchlorate (DiI) labeled bone marrow mesenchymal stem cells (BMSCs), we observe the effect of materials on the growth and proliferation of DiI labeled stem cells, and the effect of DiI labeling on patch preparation, so as to find a kind of biomaterial suitable for the growth and proliferation of BMSCs, and find a suitable cell carrier for stem cell therapy of myocardial infarction and in vivo tracing.

METHODS

Clean grade Sprague Dawley rats were selected as experimental objects, BMSCs were isolated and cultured, and the surface markers were identified by flow cytometry. After the BMSCs were cultured for 3 passages, the BMSCs were stained with DiI dye, and the BMSCs DiI and PCL biomaterial film were co-cultured. After 24 hours, the cell growth was observed under fluorescence microscope, and fixed for scanning under electron microscope. The cell proliferation was detected by CCK-8 at 1, 4, 7, 10 days of culture. The measurement data conforming to normal distribution are expressed in the form of mean ± standard deviation (X¯± s). One way ANOVA was used for comparison among groups, LSD analysis was used for pairwise comparison. The difference was statistically significant (P < 0.05).

RESULTS

BMSCs were strongly positive for CD90, CD44H, but negative for CD11b/c, CD45. Under fluorescence microscope, BMSCs DiI showed red light, fusiform or polygonal. Under the scanning electron microscope, the cell patch formed by co-culture of PCL film and DiI-BMSCs had a large number of cells on the surface and normal cell state. CCK-8 assay showed that the OD value on the first day was 0.330 ± 0.025; The OD value was 0.620 ± 0.012 on the 4th day, 1.033 ± 0.144 on the 7th day and 1.223 ± 0.133 on the 10th day. There was significant difference among the time points (P < 0.05).

CONCLUSIONS

The cell patch made of PCL film and DiI labeled BMSCs can survive and proliferate on the surface, so it can be used as a scaffold material for stem cell therapy in vivo.

Genome-wide methylome pattern predictive network analysis reveal mesenchymal stem cell's propensity to undergo cardiovascular lineage

Mesenchymal stem cells (MSCs) differentiation toward cardiovascular lineage prediction using the global methylome profile will highlight its prospective utility in regenerative medicine. We examined the propensity prediction to cardiovascular lineage using 5-Aza, a well-known cardiac lineage inducer. The customized 180 K microarray was performed and further analysis of global differentially methylated regions by Ingenuity pathway analysis (IPA) in both MSCs and 5-AC-treated MSCs. The cluster enrichment tools sorted differentially enriched genes and further annotated to construct the interactive networks. Prediction analysis revealed pathways pertaining to the cardiovascular lineage found active in the native MSCs, suggesting its higher propensity to undergo cardiac, smooth muscle cell, and endothelial lineages in vitro. Interestingly, gene interaction network also proposed majorly stemness gene network NANOG and KLF6, cardiac-specific transcription factors GATA4, NKX2.5, and TBX5 were upregulated in the native MSCs. Furthermore, the expression of cardiovascular lineage specific markers such as Brachury, CD105, CD90, CD31, KDR and various forms of ACTIN (cardiac, sarcomeric, smooth muscle) were validated in native MSCs using real time PCR and immunostaining and blotting analysis. In 5-AC-treated MSCs, mosaic interactive networks were observed to persuade towards osteogenesis and cardiac lineage, indicating that 5-AC treatment resulted in nonspecific lineage induction in MSCs, while MSCs by default have a higher propensity to undergo cardiovascular lineage.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-03058-2.

Computational and in vitro validation of cardiogenic induction of quercetin on adipose-derived mesenchymal stromal cells through the inhibition of Wnt and non-Smad-dependent TGF-β pathways

Exploiting human mesenchymal stem cells (hMSCs) was proposed as a promising therapeutic approach for cardiovascular disease due to their capacity to differentiate into cardiac cells. Though modulation of the intracellular signaling pathways dominantly WNT/β catenin and transforming growth factor-β (TGF-β) have been reported to promote differentiation of hMSCs into cardiomyocytes in the prevailing literature, a safe and reproducible system for their clinical application has not yet turned into reality. In the present study, the molecular docking-based strategy was first applied for evaluating the potency of some natural phenolic compounds in the modulation of Wnt and TGF-β signaling pathways using a vital class of crystallographic protein structures of WNT signaling regulators such as Frizzled, Disheveled, GSK3-β, β-catenin, LRP 5/6 extracellular domain, Tankyrase and their variety of active pockets. Then, the impacts of plant-derived chemical compounds on the regulation of the relevant signals for the differentiation of hMSCs into the definitive mesoderm lineage and cardiac progenitors were assessed in vitro. Data obtained revealed the synergistic activity of Wnt and TGF-β superfamily to direct cardiac differentiation in human cardiogenesis by comparing cardiac gene expression in the presence and absence of the TGF-β inhibitors. We found that the inhibitory effect of canonical Wnt/β-catenin is sufficient to cause proper cardiomyocyte differentiation, but the TGF-β pathway plays a vital role in enhancing the expression of the cardiomyocyte-specific marker (cTnT). It was found that quercetin, a p38MAPK inhibitor with the high energy dock to the active pocket of Wnt receptors, promotes cardiac differentiation via the inhibition of both Wnt and non-Smad TGF-β pathways. Altogether, data presented here can contribute to the development of a feasible and efficient cardiac differentiation protocol as an "off-the-shelf" therapeutic source using novel natural agents for cardiac repair or regeneration.

Biomolecules in cell-derived extracellular vesicle chariots as warriors to repair damaged tissues

In this review, we highlight the innovative applications of biomolecules from parent cell-derived extracellular vesicles (EVs) for tissue repair that have been developed in recent years. We evaluate the underlying mechanisms and therapeutic efficacy of each therapy. In previous literature reviews, it was most common to classify the use of EVs in tissue repair by disease type. This article reviews the role of three biomolecules in EVs in tissue repair. This review first summarizes the definitions and classifications of EVs. Then, the importance and significance of treating tissue damage with EVs are discussed. In particular, EV contents for tissue repair are three main types of biomolecules: proteins, RNAs and cell growth factors. The therapeutic and repair mechanisms of the biomolecules are discussed respectively. Finally, the development prospect and potential challenges of EV contents from highly differentiated cells as specific agents for tissue repair are summarized. When EVs are used to treat diseases such as tissue or organ damage, EVs play a role in delivery, and the real repair effect is effected by the various biomolecules carried by EVs. We believe that EV biomolecules have unparalleled advantages and clinical transformation potential for tissue repair and expect this review to inspire more intensive research work in this field.

Bidirectional relationship between cardiac extracellular matrix and cardiac cells in ischemic heart disease

Ischemic heart diseases (IHDs), including myocardial infarction and cardiomyopathies, are a leading cause of mortality and morbidity worldwide. Cardiac-derived stem and progenitor cells have shown promise as a therapeutic for IHD but are limited by poor cell survival, limited retention, and rapid washout. One mechanism to address this is to encapsulate the cells in a matrix or three-dimensional construct, so as to provide structural support and better mimic the cells' physiological microenvironment during administration. More specifically, the extracellular matrix (ECM), the native cellular support network, has been a strong candidate for this purpose. Moreover, there is a strong consensus that the ECM and its residing cells, including cardiac stem cells, have a constant interplay in response to tissue development, aging, disease progression, and repair. When externally stimulated, the cells and ECM work together to mutually maintain the local homeostasis by initially altering the ECM composition and stiffness, which in turn alters the cellular response and behavior. Given this constant interplay, understanding the mechanism of bidirectional cell-ECM interaction is essential to develop better cell implantation matrices to enhance cell engraftment and cardiac tissue repair. This review summarizes current understanding in the field, elucidating the signaling mechanisms between cardiac ECM and residing cells in response to IHD onset. Furthermore, this review highlights recent advances in native ECM-mimicking cardiac matrices as a platform for modulating cardiac cell behavior and inducing cardiac repair.

Histone Modifications in Stem Cell Development and Their Clinical Implications

Human stem cells bear a great potential for multiple therapeutic applications but at the same time constitute a major threat to human health in the form of cancer stem cells. The molecular processes that govern stem cell maintenance or differentiation have been extensively studied in model organisms or cell culture, but it has been difficult to extrapolate these insights to therapeutic applications. Recent advances in the field suggest that local and global changes in histone modifications that affect chromatin structure could influence the capability of cells to either maintain their stem cell identity or differentiate into specialized cell types. The enzymes that regulate these modifications are therefore among the prime targets for potential drugs that can influence and potentially improve the therapeutic application of stem cells. In this review, we discuss recent findings on the role of histone modifications in stem cell regulation and their potential implications for clinical applications.

Extracellular vesicles for tissue repair and regeneration: Evidence, challenges and opportunities

Extracellular vesicles (EVs) are biological nanoparticles naturally secreted by cells, acting as delivery vehicles for molecular messages. During the last decade, EVs have been assigned multiple functions that have established their potential as therapeutic mediators for a variety of diseases and conditions. In this review paper, we report on the potential of EVs in tissue repair and regeneration. The regenerative properties that have been associated with EVs are explored, detailing the molecular cargo they carry that is capable of mediating such effects, the signaling cascades triggered in target cells and the functional outcome achieved. EV interactions and biodistribution in vivo that influence their regenerative effects are also described, particularly upon administration in combination with biomaterials. Finally, we review the progress that has been made for the successful implementation of EV regenerative therapies in a clinical setting.

Novel approach to enhance aggregate migration-driven epigenetic memory which induces cardiomyogenic differentiation on a dendrimer-immobilized surface

The dynamic migratory behavior of human mesenchymal stem cells (hMSCs) has a significant impact on the epigenetic profiles that determine fate choice and lineage commitment during differentiation. Here we report a novel approach to enhance repeated migration-driven epigenetic memory which induces cardiomyogenic differentiation on a dendrimer surface with fifth generation (G5). Cells exhibited the formation of cell aggregates on the G5 surface through active migration with morphological changes, and these aggregates showed strong expression of the cardiac-specific marker cardiac troponin T (cTnT) at 10 days. When cell aggregates were passaged onto a fresh G5 surface over three passages of 40 days, the expression levels of the multiple cardiac-specific markers including GATA4, NKX2.5, MYH7, and TNNT2 were higher compared to those passaged as single cells. To investigate whether cardiomyogenic differentiation of hMSCs was enhanced by repeated aggregate migration-driven epigenetic memory, cells on the G5 surface were reseeded onto a fresh G5 surface during three passages using aggregate-based and single cell-based passage methods. Analyses of global changes in H3 histone modifications exhibited pattern of increased H3K9ac and H3K27me3, and decreased H3K9me3 in aggregate-based passage cultures during three passages. However, the pattern of their histone modification on the PS surface was repeated after the initialization and reformation during three passages in single cell-based passage cultures. Thus, repetitive aggregate migratory behavior during aggregate-based passage led to a greater degree of histone modification, as well as gene expression changes suggestive of cardiomyogenic differentiation.

Mesenchymal Stem Cells for Cardiac Regeneration: from Differentiation to Cell Delivery

Mesenchymal stem cells (MSCs) are so far the most widely researched stem cells in clinics and used as an experimental cellular therapy module, particularly in cardiac regeneration and repair. Ever since the discovery of cardiomyogenesis induction in MSCs, a wide variety of differentiation protocols have been extensively used in preclinical models. However, pre differentiated MSC-derived cardiomyocytes have not been used in clinical trials; highlighting discrepancies and limitations in its use as a source of derived cardiomyocytes for transplantation to improve the damaged heart function. Therefore, this review article focuses on the strategies used to derive cardiomyocytes-like cells from MSCs isolated from three widely used tissue sources and their differentiation efficiencies. We have further discussed the role of MSCs in inducing angiogenesis as a cellular precursor to endothelial cells and its secretory aspects including exosomes. We have then discussed the strategies used for delivering cells in the damaged heart and how its retention plays a critical role in the overall outcome of the therapy. We have also conversed about the scope of the local and systemic modes of delivery of MSCs and the application of biomaterials to improve the overall delivery efficacy and function. We have finally discussed the advantages and limitations of cell delivery to the heart and the future scope of MSCs in cardiac regenerative therapy.

Cardiac Differentiation of Mesenchymal Stem Cells: Impact of Biological and Chemical Inducers

Cardiovascular disorders (CVDs) are the leading cause of global death, widely occurs due to irreparable loss of the functional cardiomyocytes. Stem cell-based therapeutic approaches, particularly the use of Mesenchymal Stem Cells (MSCs) is an emerging strategy to regenerate myocardium and thereby improving the cardiac function after myocardial infarction (MI). Most of the current approaches often employ the use of various biological and chemical factors as cues to trigger and modulate the differentiation of MSCs into the cardiac lineage. However, the recent advanced methods of using specific epigenetic modifiers and exosomes to manipulate the epigenome and molecular pathways of MSCs to modify the cardiac gene expression yield better profiled cardiomyocyte like cells in vitro. Hitherto, the role of cardiac specific inducers triggering cardiac differentiation at the cellular and molecular level is not well understood. Therefore, the current review highlights the impact and recent trends in employing biological and chemical inducers on cardiac differentiation of MSCs. Thereby, deciphering the interactions between the cellular microenvironment and the cardiac inducers will help us to understand cardiomyogenesis of MSCs. Additionally, the review also provides an insight on skeptical roles of the cell free biological factors and extracellular scaffold assisted mode for manipulation of native and transplanted stem cells towards translational cardiac research.

Recent advances in bioprinting technologies for engineering cardiac tissue

Annually increasing incidence of cardiac-related disorders and cardiac tissue's minimal regenerative capacity have motivated the researchers to explore effective therapeutic strategies. In the recent years, bioprinting technologies have witnessed a great wave of enthusiasm and have undergone steady advancements over a short period, opening the possibilities for recreating engineered functional cardiac tissue models for regenerative and diagnostic applications. With this perspective, the current review delineates recent developments in the sphere of engineered cardiac tissue fabrication, using traditional and advanced bioprinting strategies. The review also highlights different printing ink formulations, available cellular opportunities, and aspects of personalized medicines in the context of cardiac tissue engineering and bioprinting. On a concluding note, current challenges and prospects for further advancements are also discussed.

Growth characteristics of human bone marrow mesenchymal stromal cells at cultivation on synthetic polyelectrolyte nanofilms in vitro

This study examines the adhesive properties and cytotoxicity of polyelectrolyte nanofilms from polyethyleneimine (PEI), polyallylamine hydrochloride (PAH) and sodium polystyrene sulfonate (PSS) on human bone marrow mesenchymal stromal cells (h-MSCs) and mouse adipose tissue (m-MSC) in vitro. Films are formed on 24- and 96-well culture plates in the combinations: PEI, PAH, PEI-PSS, PEI-PSS-PAH, PEI-PSS-PEI. An analysis of the culture results show that direct contact of h-MSCs with the PEI surface promotes adhesion (93–95% of adhesive cells versus 40% in the control). On the PEI surface, h-MSCs are evenly distributed, form colonies and 80% monolayer after 72 h of culture, as in the control on culture plastic. On nanofilms from PAH and PEI-PSS-PAH, cells grow in the form of rosette-like colonies with long and thin processes similar to neurites. The cytotoxic properties of PSS were revealed in direct contact with h-MSCs (more than 40% of nonviable cells with damaged plasma membranes). On the PSS surface, cells lost their adhesiveness. To culture and stably grow the cell mass of h-MSCs, it is better to use monolayer nanofilms made of highly adhesive and non-toxic PEI polyelectrolyte, which can bind the growth factors of blood serum and platelet lysate, ensuring the growth of h-MSCs under in vitro deprivation conditions.

Mesenchymal Stem Cell-Based Therapy for Diabetes Mellitus: Enhancement Strategies and Future Perspectives

Diabetes mellitus (DM), a chronic disorder of carbohydrate metabolism, is characterized by the unbridled hyperglycemia resulted from the impaired ability of the body to either produce or respond to insulin. As a cell-based regenerative therapy, mesenchymal stem cells (MSCs) hold immense potency for curing DM duo to their easy isolation, multi-differentiation potential, and immunomodulatory property. However, despite the promising efficacy in pre-clinical animal models, naive MSC administration fails to exhibit clinically satisfactory therapeutic outcomes, which varies greatly among individuals with DM. Recently, numbers of innovative strategies have been applied to improve MSC-based therapy. Preconditioning, genetic modification, combination therapy and exosome application are representative strategies to maximize the therapeutic benefits of MSCs. Therefore, in this review, we summarize recent advancements in mechanistic studies of MSCs-based treatment for DM, and mainly focus on the novel approaches aiming to improve the anti-diabetic potentials of naive MSCs. Additionally, the potential directions of MSCs-based therapy for DM are also proposed at a glance.

Dielectrophoretic Characterization of Tenogenically Differentiating Mesenchymal Stem Cells

Tendons are collagenous musculoskeletal tissues that connect muscles to bones and transfer the forces necessary for movement. Tendons are susceptible to injury and heal poorly, with long-term loss of function. Mesenchymal stem cell (MSC)-based therapies are a promising approach for treating tendon injuries but are challenged by the difficulties of controlling stem cell fate and of generating homogenous populations of stem cells optimized for tenogenesis (differentiation toward tendon). To address this issue, we aim to explore methods that can be used to identify and ultimately separate tenogenically differentiated MSCs from non-tenogenically differentiated MSCs. In this study, baseline and tenogenically differentiating murine MSCs were characterized for dielectric properties (conductivity and permittivity) of their outer membrane and cytoplasm using a dielectrophoretic (DEP) crossover technique. Experimental results showed that unique dielectric properties distinguished tenogenically differentiating MSCs from controls after three days of tenogenic induction. A single shell model was used to quantify the dielectric properties and determine membrane and cytoplasm conductivity and permittivity. Together, cell responses at the crossover frequency, cell morphology, and shell models showed that changes potentially indicative of early tenogenesis could be detected in the dielectric properties of MSCs as early as three days into differentiation. Differences in dielectric properties with tenogenesis indicate that the DEP-based label-free separation of tenogenically differentiating cells is possible and avoids the complications of current label-dependent flow cytometry-based separation techniques. Overall, this work illustrates the potential of DEP to generate homogeneous populations of differentiated stem cells for applications in tissue engineering and regenerative medicine.

The Role of Melanotransferrin (CD228) in the regulation of the differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells (hBM-MSC)

Melanotransferrin (CD228), firstly reported as a melanoma-associated antigen, is a membrane-bound glycoprotein of an iron-binding transferrin homolog. CD228 was found to be expressed significantly higher in human bone marrow-derived mesenchymal stem cells (hBM-MSC) than in human embryonic fibroblasts (FB) by RT-PCR, western blotting and flow cytometry. The expression of CD228 declined in aged hBM-MSC as osteogenesis-related genes did. We examined a possible role for CD228 in the regulation of osteogenesis and adipogenesis of hBM-MSC. Surprisingly, siRNA-mediated CD228 knockdown increased the expression of the transcription factor DLX5 and enhanced osteogenesis of hBM-MSC evidenced by an increased expression of the runt-related transcription factor 2 (RUNX2), osterix (Osx), and osteocalcin (OC), as well as higher alkaline phosphatase (ALP) activity and extracellular calcium deposition. Interestingly, hBM-MSC transfected with CD228 siRNA also showed an increase in intracellular lipid level during adipogenesis, indicated by oil red O staining of differentiated adipocytes. Overall, our study unveils CD228 as a cell surface molecule expressed by young hBM-MSC, but not by FB. It also provides evidence to suggest a role for CD228 as a negative regulator of osteogenesis and of lipid accumulation during adipogenesis in hBM-MSC in vitro.

SETD4 in the Proliferation, Migration, Angiogenesis, Myogenic Differentiation and Genomic Methylation of Bone Marrow Mesenchymal Stem Cells

Epigenetic modification is a crucial mechanism affecting the biological function of stem cells. SETD4 is a histone methyltransferase, and its biological role in bone marrow mesenchymal stem cells (BMSCs) is currently unknown. In this study, we employed CRISPR/Cas9 technology edited mouse model and found that SETD4 knockout significantly promoted the proliferation of BMSCs, impaired BMSCs migration and differentiation potentials of lineages of cardiacmyocyte and smooth muscle cell, and even the angiogenesis via paracrine of VEGF. Through Reduced Representation Bisulfite Sequencing (RRBS) method, we verified that the overall genomic methylation of BMSCs in the SETD4 knockout group only was decreased by 0.47 % compared with wild type. However, the changed genomic methylation covers a total of 96,331 differential methylated CpG sites and 8,692 differential methylation regions (DMRs), with part of them settled in promoter regions. Bioinformatic analysis revealed that differential CpG islands and DMRs in promoter impacted 270 GO functions and 34 KEGG signaling pathways, with some closely related to stem cell biology. Mechanismly, SETD4 knockout inhibited sets of monomethylases and dimethylases for histone lysine, along with significant changes in some factors including Nkx2.5, Gata4, Gli2, Grem2, E2f7, Map7, Nr2f2 and Shox2 that associated with stem cell biology. These results are the first to reveal that even though SETD4 changes the genome's overall methylation to a limited extent in BMSCs, it still affects the numerous cellular functions and signaling pathways, implying SETD4-altered genomic methylation serves a crucial molecular role in BMSCs' biological functions.

Human cardiomyocyte-derived exosomes induce cardiac gene expressions in mesenchymal stromal cells within 3D hyaluronic acid hydrogels and in dose-dependent manner

Accomplishing a reliable lineage-specific differentiation of stem cells is vital in tissue engineering applications, however, this need remained unmet. Extracellular nanovesicles (particularly exosomes) have previously been shown to have this potential owing to their rich biochemical content including proteins, nucleic acids and metabolites. In this work, the potential of human cardiomyocytes-derived exosomes to induce in vitro cardiac gene expressions in human mesenchymal stem cells (hMSCs) was evaluated. Cardiac exosomes (CExo) were integrated with hyaluronic acid (HA) hydrogel, which was functionalized with tyramine (HA-Tyr) to enable the development of 3D (three dimensional), robust and bioactive hybrid cell culture construct through oxidative coupling. In HA-Tyr/CExo 3D hybrid hydrogels, hMSCs exhibited good viability and proliferation behaviours. Real time quantitative polymerase chain reaction (RT-qPCR) results demonstrated that cells incubated within HA-Tyr/CExo expressed early cardiac progenitor cell markers (GATA4, Nkx2.5 and Tbx5), but not cTnT, which is expressed in the late stages of cardiac differentiation and development. The expressions of cardiac genes were remarkably increased with increasing CExo concentration, signifying a dose-dependent induction of hMSCs. This report, to some extent, explains the potential of tissue-specific exosomes to induce lineage-specific differentiation. However, the strategy requires further mechanistic explanations so that it can be utilized in translational medicine.

In situ differentiation of human-induced pluripotent stem cells into functional cardiomyocytes on a coaxial PCL-gelatin nanofibrous scaffold

Human-induced pluripotent stem cells (hiPSCs) derived cardiomyocytes (hiPSC-CMs) have been explored for cardiac regeneration and repair as well as for the development of in vitro 3D cardiac tissue models. Existing protocols for cardiac differentiation of hiPSCs utilize a 2D culture system. However, the efficiency of hiPSC differentiation to cardiomyocytes in 3D culture systems has not been extensively explored. In the present study, we investigated the efficiency of cardiac differentiation of hiPSCs to functional cardiomyocytes on 3D nanofibrous scaffolds. Coaxial polycaprolactone (PCL)-gelatin fibrous scaffolds were fabricated by electrospinning and characterized using scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy. hiPSCs were cultured and differentiated into functional cardiomyocytes on the nanofibrous scaffold and compared with 2D cultures. To assess the relative efficiencies of both the systems, SEM, immunofluorescence staining and gene expression analyses were performed. Contractions of differentiated cardiomyocytes were observed in 2D cultures after 2 weeks and in 3D cultures after 4 weeks. SEM analysis showed no significant differences in the morphology of cells differentiated on 2D versus 3D cultures. However, gene expression data showed significantly increased expression of cardiac progenitor genes (ISL-1, SIRPA) in 3D cultures and cardiomyocytes markers (TNNT, MHC6) in 2D cultures. In contrast, immunofluorescence staining showed no substantial differences in the expression of NKX-2.5 and α-sarcomeric actinin. Furthermore, uniform migration and distribution of the in situ differentiated cardiomyocytes was observed in the 3D fibrous scaffold. Overall, our study demonstrates that coaxial PCL-gelatin nanofibrous scaffolds can be used as a 3D culture platform for efficient differentiation of hiPSCs to functional cardiomyocytes.

Mesenchymal stem cells for restoring endometrial function: An infertility perspective

BACKGROUND

Mesenchymal stem cells (MSCs) can be derived from several tissues such as bone marrow, placenta, adipose tissue, or endometrial tissue. MSCs gain a lot of attention for cell-based therapy due to their characteristics including differentiation ability and immunomodulatory effect. Preclinical and clinical studies demonstrated that MSCs can be applied to treat female infertility by improving of the functions of ovary and uterus. This mini- review focuses on the current study of treatment of endometrial infertility by using MSCs.

METHODS

The present study performed a literature review focusing on the effect of MSCs for treatment of women infertility caused by endometrial dysfunction.

RESULTS

Bone marrow-, umbilical cord-, adipose-, amniotic-, and menstruation-derived MSCs enhance endometrial cell proliferation, injury repairs as well as reducing scar formation. The beneficial mechanism probably via immunomodulatory, cell differentiation, stimulates endometrial cell proliferation and down-regulation of fibrosis genes. The major advantage of using MSCs is to improve endometrial functions resulting in increased implantation and pregnancy.

CONCLUSIONS

MSCs exhibit a potential for endometrial infertility treatment. Adipose- and menstruation-derived stem cells show advantages over other sources because the cells can be derived easily and do not causes graft rejection after autologous transplantation.

Human Mesenchymal Stem Cells: The Present Alternative for High-Incidence Diseases, Even SARS-Cov-2

Mesenchymal stem cells (MSCs), defined as plastic adherent cells with multipotent differentiation capacity in vitro, are an emerging and valuable tool to treat a plethora of diseases due to their therapeutic mechanisms such as their paracrine activity, mitochondrial and organelle transfer, and transfer of therapeutic molecules via exosomes. Nowadays, there are more than a thousand registered clinical trials related to MSC application around the world, highlighting MSC role on difficult-to-treat high-incidence diseases such as the current COVID-19, HIV infections, and autoimmune and metabolic diseases. Here, we summarize a general overview of MSCs and their therapeutic mechanisms; also, we discuss some of the novel clinical trial protocols and their results as well as a comparison between the number of registries, countries, and search portals.

Conditioned medium harvested from Hif1α engineered mesenchymal stem cells ameliorates LAD-occlusion -induced injury in rat acute myocardial ischemia model

Acute myocardial infarction (AMI) is the most common type of ischemic heart diseases with a high mortality rate. Although recent advances in medical cares and therapies have increased the patient's outcomes, but, still there is no real and effective therapeutic modality for AMI. Hence, development of novel therapeutic strategies is under focus of investigations. MSCs-based therapy has been proposed for AMI, though its efficacy is controversial yet. It is believed that MSCs exert their healing effects via secretion of growth factors/cytokines. However, these cells produce a very minute amount of the factors under normal cultivation. Here, in an attempt to improve the potential therapeutic effect of MSCs-derived conditioned medium (CM) on AMI, we transfected the cells with a recombinant plasmid encoding Hif1α-3A (a mutant form of Hif1α stable under normoxic condition), so Hif1α expression and secretion into CM (MSCs-Hif1α-CM) could be up-regulated under normoxic condition. The therapeutic potential of the MSCs-Hif1α-3A-CM was investigated in a rat model of AMI and compared to the CM harvested from non-manipulated MSCs. Our results showed that the MSCs-Hif1α-3A-CM mitigated MI-induced tissues injury, decreased fibrosis, reduced apoptosis, and limited infarct area size. These findings propose a potential therapeutic strategy for treatment of AMI. However, further preclinical and clinical investigations in this regard are still needed.