Circular RNA expression profiles during the differentiation of human umbilical cord-derived mesenchymal stem cells into cardiomyocyte-like cells

Competing endogenous RNA network analysis of Turner syndrome patient-specific iPSC-derived cardiomyocytes reveals dysregulation of autosomal heart development genes by altered dosages of X-inactivation escaping non-coding RNAs

BACKGROUND

A 45,X monosomy (Turner syndrome, TS) is the only chromosome haploinsufficiency compatible with life. Nevertheless, the surviving TS patients still suffer from increased morbidity and mortality, with around one-third of them subjecting to heart abnormalities. How loss of one X chromosome drive these conditions remains largely unknown.

METHODS

Here, we have generated cardiomyocytes (CMs) from wild-type and TS patient-specific induced pluripotent stem cells and profiled the mRNA, lncRNA and circRNA expression in these cells.

RESULTS

We observed lower beating frequencies and higher mitochondrial DNA copies per nucleus in TS-CMs. Moreover, we have identified a global transcriptome dysregulation of both coding and non-coding RNAs in TS-CMs. The differentially expressed mRNAs were enriched of heart development genes. Further competing endogenous RNA network analysis revealed putative regulatory circuit of autosomal genes relevant with mitochondrial respiratory chain and heart development, such as COQ10A, RARB and WNT2, mediated by X-inactivation escaping lnc/circRNAs, such as lnc-KDM5C-4:1, hsa_circ_0090421 and hsa_circ_0090392. The aberrant expressions of these genes in TS-CMs were verified by qPCR. Further knockdown of lnc-KDM5C-4:1 in wild-type CMs exhibited significantly reduced beating frequencies.

CONCLUSIONS

Our study has revealed a genomewide ripple effect of X chromosome halpoinsufficiency at post-transcriptional level and provided insights into the molecular mechanisms underlying heart abnormalities in TS patients.

Autophagy of umbilical cord mesenchymal stem cells induced by rapamycin conduces to pro-angiogenic function of the conditioned medium

Angiogenesis is critical for wound healing and tissue repair. Umbilical cord mesenchymal stem cells (UCMSCs)-conditioned medium has certain actions to promote angiogenesis, and is expected for wound healing and tissue repair. However, recent studies showed that the pro-angiogenic efficacy of unprocessed MSCs-conditioned medium is low, and insufficient for tissue repair. Autophagy is a process for protein recycling and a contributor for cell exocrine, which may enhance pro-angiogenic efficacy of the conditioned medium by stimulating cytokine release from UCMSCs. Therefore, in this study we attempted to obtain enhanced autophagy in UCMSCs using different concentrations of rapamycin and compared pro-angiogenic functions of the conditioned media. The in vitro data showed that although 100 nM-10 μM rapamycin all could induce autophagy in UCMSCs, 100 nM was the best dose to optimize the angiogenic effect of the conditioned medium. The in vivo data also showed that pro-angiogenic effect of the optimized conditioned medium was more obvious than that of the control conditioned medium (0 nM group) in the injected matrigel plaques. Further, the expressions of VEGF, FGF-2, MMP-9, PDGF-α and PDGF-β were markedly increased in UCMSCs treated with 100 nM rapamycin. In conclusion, appropriately enhancing autophagy of UCMSC can improve pro-angiogenic efficacy of the conditioned medium, which may optimize therapeutic applications of UCMSCs-conditioned medium in wound healing and tissue repair.

hucMSCs Treatment Ameliorated Pulmonary Fibrosis via Downregulating the circFOXP1-HuR-EZH2/STAT1/FOXK1 Autophagic Axis

This study was performed to determine the effect of human umbilical cord mesenchymal stem cells (hucMSCs) treatment on pulmonary fibrosis and investigate the circFOXP1-mediated autophagic mechanism of hucMSCs treatment. Pulmonary fibrosis models were established by spraying bleomycin in mice and TGF-β1 treatment of MRC-5 cells. Results showed that hucMSCs were retained in lung and hucMSCs treatment alleviated pulmonary fibrosis. Morphological staining indicated that hucMSCs-treated mice had thinner alveolar walls, effectively improved alveolar structure, significantly reduced alveolar inflammation, and decreased collagen deposition than control mice. Fibrotic proteins, including vimentin, α-SMA, collagens I and III, and the differentiation-related protein S100 calcium-binding protein A4 was reduced considerably in the hucMSCs-treated group. The mechanistic study revealed that the inhibition of hucMSCs treatment on pulmonary fibrogenesis depended on downregulating circFOXP1, in which hucMSCs treatment promoted circFOXP1-mediated autophagy process via blocking the nuclear human antigen R (HuR) translocation and promoting the HuR degradation, leading to a marked decrease in autophagy negative regulators EZH2, STAT1, and FOXK1. In conclusion, hucMSCs treatment significantly improved pulmonary fibrosis by downregulating the circFOXP1-HuR-EZH2/STAT1/FOXK1 autophagic axis. hucMSCs can act as an effective treatment for pulmonary fibrosis.

Mesenchymal Stem Cell-Derived Long Noncoding RNAs in Cardiac Injury and Repair

Cardiac injury, such as myocardial infarction and heart failure, remains a significant global health burden. The limited regenerative capacity of the adult heart poses a challenge for restoring its function after injury. Mesenchymal stem cells (MSCs) have emerged as promising candidates for cardiac regeneration due to their ability to differentiate into various cell types and secrete bioactive molecules. In recent years, attention has been given to noncoding RNAs derived from MSCs, particularly long noncoding RNAs (lncRNAs), and their potential role in cardiac injury and repair. LncRNAs are RNA molecules that do not encode proteins but play critical roles in gene regulation and cellular responses including cardiac repair and regeneration. This review focused on MSC-derived lncRNAs and their implications in cardiac regeneration, including their effects on cardiac function, myocardial remodeling, cardiomyocyte injury, and angiogenesis. Understanding the molecular mechanisms of MSC-derived lncRNAs in cardiac injury and repair may contribute to the development of novel therapeutic strategies for treating cardiovascular diseases. However, further research is needed to fully elucidate the potential of MSC-derived lncRNAs and address the challenges in this field.

The Molecular Regulatory Mechanism in Multipotency and Differentiation of Wharton's Jelly Stem Cells

Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) are isolated from Wharton's jelly tissue of umbilical cords. They possess the ability to differentiate into lineage cells of three germ layers. WJ-MSCs have robust proliferative ability and strong immune modulation capacity. They can be easily collected and there are no ethical problems associated with their use. Therefore, WJ-MSCs have great tissue engineering value and clinical application prospects. The identity and functions of WJ-MSCs are regulated by multiple interrelated regulatory mechanisms, including transcriptional regulation and epigenetic modifications. In this article, we summarize the latest research progress on the genetic/epigenetic regulation mechanisms and essential signaling pathways that play crucial roles in pluripotency and differentiation of WJ-MSCs.

The beneficial effects of mesenchymal stem cells and their exosomes on myocardial infarction and critical considerations for enhancing their efficacy

Mesenchymal stem cells (MSCs) are multipotent stromal cells with regenerative, anti-inflammatory, and immunomodulatory properties. MSCs and their exosomes significantly improved structural and functional alterations after myocardial infarction (MI) in preclinical studies and clinical trials. By reprograming intracellular signaling pathways, MSCs attenuate inflammatory response, oxidative stress, apoptosis, pyroptosis, and endoplasmic reticulum (ER) stress and improve angiogenesis, mitochondrial biogenesis, and myocardial remodeling after MI. MSC-derived exosomes contain a mixture of non-coding RNAs, growth factors, anti-inflammatory mediators, and anti-fibrotic factors. Although primary results from clinical trials were promising, greater efficacies can be achieved by controlling several modifiable factors. The optimum timing of transplantation, route of administration, origin of MSCs, number of doses, and number of cells per dose need to be further investigated by future studies. Newly, highly effective MSC delivery systems have been developed to improve the efficacy of MSCs and their exosomes. Moreover, MSCs can be more efficacious after being pretreated with non-coding RNAs, growth factors, anti-inflammatory or inflammatory mediators, and hypoxia. Similarly, viral vector-mediated overexpression of particular genes can augment the protective effects of MSCs on MI. Therefore, future clinical trials must consider these advances in preclinical studies to properly reflect the efficacy of MSCs or their exosomes for MI.

UCMSCs-derived exosomal circHIPK3 promotes ulcer wound angiogenesis of diabetes mellitus via miR-20b-5p/Nrf2/VEGFA axis

AIMS

Experiments confirmed that circular RNAs contributed to the pathogenesis of diabetic foot ulcers (DFUs). CircHIPK3 was upregulated in type 2 diabetes mellitus (T2DM), but its role in DFU remained unknown. Our study aimed to investigate the regulatory functions of exosomal circHIPK3 and its potential mechanisms in DFU.

METHODS

Exosomal size and distribution, marker proteins, and circHIPK3 levels were evaluated by transmission electron microscope, ExoView R200, western blot, and qRT-PCR. Flow cytometry, MTT, Wound healing assays, and tube formation assays were used to assess the roles of exosomal circHIPK3 in high glucose (HG)-treated human umbilical vein endothelial cells (HUVECs). The relationships between Nrf2/VEGFA/circHIPK3 and miR-20b-5p, and between Nrf2 and VEGFA were determined by luciferase reporter assay and RNA immunoprecipitation. We used cell and mice models to investigate the mechanisms of exosomal circHIPK3 under diabetic conditions.

RESULTS

CircHIPK3 was significantly upregulated in exo-circHIPK3 rather than exo-vector. Exo-circHIPK3 remarkably inhibited cell apoptosis but promoted cell proliferation, migration, and tube formation in HG-treated HUVECs. Luciferase reporter and RIP assays showed that miR-20b-5p targeted and inhibited Nrf2 and VEGFA, and circHIPK3 acted as a ceRNA of miR-20b-5p to inhibit the binding to its downstream genes Nrf2 and VEGFA. Mechanistically, circHIPK3 promoted cell proliferation, migration, and angiogenesis via downregulating miR-20b-5p to upregulate Nrf2 and VEGFA. However, the overexpressed miR-20b-5p could abolish the promoting effects of circHIPK3 overexpression on cell proliferation, migration, and tube formation under HG conditions.

CONCLUSION

UCMSCs-derived exosomal circHIPK3 protected HG-treated HUVECs via miR-20b-5p/Nrf2/VEGFA axis. The exosomal circHIPK3 might be a therapeutic candidate to treat DFU.

Analysis of circRNAs profile in TNF-α treated DPSC

Background

Pulpitis often are characterized as sustained inflammation and impaired pulp self-repair. Circular RNAs (circRNAs) have been reported to be involved in the development of inflammation, but their influence in pulpitis is still unidentified, which was examined in our research.

Methods

In this study, TNF-α (20 ng/mL) was used to treat DPSCs, then MTS identified cell proliferation. The circRNAs profile in DPSCs with or without TNF-α treatment was evaluated using RNA sequencing and subsequently by bioinformatics analysis. After that, the circular structure was assessed using agarose gel electrophoresis, followed by Sanger sequencing. And the circRNAs expression was ratified using quantitative real-time polymerase chain reaction in cell and tissues samples. Additionally, the plausible mechanism of circRNAs was envisaged, and the circRNA-miRNA-mRNA linkage was plotted using Cytoscape.

Results

The treatment of TNF-α inhibited cell proliferation capabilities in DPSCs, which also made 1195 circRNA expressions undergo significant alterations. Among these changes, 11 circRNAs associated with inflammation were chosen for circular structure verification, and only seven circRNAs (hsa_circ_0001658, hsa_circ_0001978, hsa_circ_0003910, hsa_circ_0004314, hsa_circ_0004417, hsa_circ_0035915, and hsa_circ_0002545) had circular structure. Additionally, five circRNAs expressions (hsa_circ_0001978, hsa_circ_0003910, hsa_circ_0004314, hsa_circ_0004417, and hsa_circ_0035915) had significantly altered between with or without TNF-α treated DPSCs. Furthermore, hsa_circ_0001978 and hsa_circ_0004417 were increased in patients suffering from pulpitis. Furthermore, their ceRNA linkage and Kyoto Encyclopedia of Genes and Genomes analysis suggested that these two circRNAs may participate in the inflammation development of pulpitis via mitogen-activated protein kinase and the Wnt signaling pathway.

Conclusion

This study revealed that the circRNAs profile was altered in TNF-α treated DPSCs. Also, hsa_circ_0001978 and hsa_circ_0004417 may be involved in the inflammation progress of pulpitis. These outcomes provided the latest information for additional research on pulpitis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02267-2.

Emerging roles of circular RNAs in stem cells

Circular RNAs (circRNAs) are a novel class of noncoding RNAs that widely exist in eukaryotes. As a new focus in the field of molecular regulation, circRNAs have attracted much attention in recent years. Previous studies have confirmed that circRNAs are associated with many physiological and pathological processes. CircRNAs also participate in the regulation of stem cells. Stem cells have the properties of self-renewal and differentiation, which make stem cell therapy popular. CircRNAs may serve as new targets in stem cell therapy due to their regulation in stem cells. However, the underlying relationships between circRNAs and stem cells are still being explored. In this review, we briefly summarize the effects of circRNAs on stem cells, in the context of biological activities, aging and apoptosis, and aberrant changes. Moreover, we also examine the biological roles of stem cell-derived exosomal circRNAs. We believe our review will provide insights into the effects of circRNAs on stem cells.

Noncoding RNAs and Their Response Predictive Value in Azacitidine-treated Patients With Myelodysplastic Syndrome and Acute Myeloid Leukemia With Myelodysplasia-related Changes

BACKGROUND/AIM

Prediction of response to azacitidine (AZA) treatment is an important challenge in hematooncology. In addition to protein coding genes (PCGs), AZA efficiency is influenced by various noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs), circular RNAs (circRNAs), and transposable elements (TEs).

MATERIALS AND METHODS

RNA sequencing was performed in patients with myelodysplastic syndromes or acute myeloid leukemia before AZA treatment to assess contribution of ncRNAs to AZA mechanisms and propose novel disease prediction biomarkers.

RESULTS

Our analyses showed that lncRNAs had the strongest predictive potential. The combined set of the best predictors included 14 lncRNAs, and only four PCGs, one circRNA, and no TEs. Epigenetic regulation and recombinational repair were suggested as crucial for AZA response, and network modeling defined three deregulated lncRNAs (CTC-482H14.5, RP11-419K12.2, and RP11-736I24.4) associated with these processes.

CONCLUSION

The expression of various ncRNAs can influence the effect of AZA and new ncRNA-based predictive biomarkers can be defined.

Circular RNAs in stem cells: from basic research to clinical implications

Circular RNAs (circRNAs) are a special class of endogenous RNAs with a wide variety of pathophysiological functions via diverse mechanisms, including transcription, microRNA (miRNA) sponge, protein sponge/decoy, and translation. Stem cells are pluripotent cells with unique properties of self-renewal and differentiation. Dysregulated circRNAs identified in various stem cell types can affect stem cell self-renewal and differentiation potential by manipulating stemness. However, the emerging roles of circRNAs in stem cells remain largely unknown. This review summarizes the major functions and mechanisms of action of circRNAs in stem cell biology and disease progression. We also highlight circRNA-mediated common pathways in diverse stem cell types and discuss their diagnostic significance with respect to stem cell-based therapy.

Circular RNA Expression for Dilated Cardiomyopathy in Hearts and Pluripotent Stem Cell-Derived Cardiomyocytes

Dilated cardiomyopathy (DCM) is a type of heart disease delimited by enlargement and dilation of one or both of the ventricles along with damaged contractility, which is often accompanied by the left ventricular ejection fraction (LVEF) less than 40%. DCM is progressive and always leads to heart failure. Circular RNAs (circRNAs) are unique species of noncoding RNAs featuring high cell-type specificity and long-lasting conservation, which normally are involved in the regulation of heart failure and DCM recently. So far, a landscape of various single gene or polygene mutations, which can cause complex human cardiac disorders, has been investigated by human-induced pluripotent stem cell (hiPSC) technology. Furthermore, DCM has been modeled as well, providing new perspectives on the disease study at a cellular level. In addition, current genome editing methods can not only repair defects of some genes, but also rescue the disease phenotype in patient-derived iPSCs, even introduce pathological-related mutations into wild-type strains. In this review, we gather up the aspects of the circRNA expression and mechanism in the DCM disease scenario, facilitating understanding in DCM development and pathophysiology in the molecular level. Also, we offer an update on the most relevant scientific progress in iPSC modeling of gene mutation–induced DCM.

Non-Coding RNAs in Stem Cell Regulation and Cardiac Regeneration: Current Problems and Future Perspectives

Although advances in rapid revascularization strategies following acute myocardial infarction (AMI) have led to improved short and long-term outcomes, the associated loss of cardiomyocytes and the subsequent remodeling result in an impaired ventricular function that can lead to heart failure or death. The poor regenerative capacity of the myocardium and the current lack of effective regenerative therapies have driven stem cell research in search of a possible solution. One approach involves the delivery of stem cells to the site of injury in order to stimulate repair response. Although animal studies initially delivered promising results, the application of similar techniques in humans has been hampered by poor target site retention and oncogenic considerations. In response, several alternative strategies, including the use of non-coding RNAs (ncRNAs), have been introduced with the aim of activating and regulating stem cells or inducing stem cell status in resident cells. Circular RNAs (circRNAs) and microRNAs (miRNAs) are ncRNAs with pivotal functions in cell proliferation and differentiation, whose role in stem cell regulation and potential significance for the field of cardiac regeneration is the primary focus of this review. We also address the general advantages of ncRNAs as promising drivers of cardiac regeneration and potent stem cell regulators.

Functions and mechanisms of circular RNAs in regulating stem cell differentiation

Stem cells are a class of undifferentiated cells with great self-renewal and differentiation capabilities that can differentiate into mature cells in specific tissue types. Stem cell differentiation plays critical roles in body homoeostasis, injury repair and tissue generation. The important functions of stem cell differentiation have resulted in numerous studies focusing on the complex molecular mechanisms and various signalling pathways controlling stem cell differentiation. Circular RNAs (circRNAs) are a novel class of noncoding RNAs with a covalently closed structure present in eukaryotes. Numerous studies have highlighted important biological functions of circRNAs, and they play multiple regulatory roles in various physiological and pathological processes. Importantly, multiple lines of evidence have shown the abnormal expression of numerous circRNAs during stem cell differentiation, and some play a role in regulating stem cell differentiation, highlighting the role of circRNAs as novel biomarkers of stem cell differentiation and novel targets for stem cell-based therapy. In this review, we systematically summarize and discuss recent advances in our understanding of the roles and underlying mechanisms of circRNAs in modulating stem cell differentiation, thus providing guidance for future studies to investigate stem cell differentiation and stem cell-based therapy.Abbreviations: CircRNAs: circular RNAs; ESCs: embryonic stem cells; ADSCs: adipose-derived mesenchymal stem cells; ecircRNAs: exonic circRNAs; EIciRNAs: exon-intron circRNAs; eiRNAs: circular intronic RNAs; tricRNAs: tRNA intronic circRNAs; pol II: polymerase II; snRNP: small nuclear ribonucleoprotein; m6A: N6-methyladenosine; AGO2: Argonaute 2; RBPs: RNA-binding proteins; MBNL: muscleblind-like protein 1; MSCs: mesenchymal stem cells; hiPSCs: human induced pluripotent stem cells; hiPSC-CMs: hiPSC-derived cardiomyocytes; hBMSCs: human bone marrow mesenchymal stem cells; hADSCs: human adipose-derived mesenchymal stem cells; hDPSCs: human dental pulp stem cells; RNA-seq: high-throughput RNA sequencing; HSCs: haematopoietic stem cells; NSCs: neural stem cells; EpSCs: epidermal stem cells; hESCs: human embryonic stem cells; mESCs: murine embryonic stem cells; MNs: motor neurons; SSUP: small subunit processome; BMSCs: bone marrow-derived mesenchymal stem cells; OGN: osteoglycin; GIOP: glucocorticoid‑induced osteoporosis; CDR1as: cerebellar degeneration-related protein 1 transcript; SONFH: steroid-induced osteogenesis of the femoral head; rBMSCs: rat bone marrow-derived mesenchymal stem cells; QUE: quercetin; AcvR1b: activin A receptor type 1B; BSP: bone sialoprotein; mADSCs: mouse ADSCs; PTBP1: polypyrimidine tract-binding protein; ER: endoplasmic reticulum; hUCMSCs: MSCs derived from human umbilical cord; MSMSCs: maxillary sinus membrane stem cells; SCAPs: stem cells from the apical papilla; MyoD: myogenic differentiation protein 1; MSTN: myostatin; MEF2C: myocyte enhancer factor 2C; BCLAF1: BCL2-associated transcription factor 1; EpSCs: epidermal stem cells; ISCs: intestinal stem cells; NSCs: neural stem cells; Lgr5+ ISCs: crypt base columnar cells; ILCs: innate lymphoid cells.

Circular RNA in cardiovascular disease: Expression, mechanisms and clinical prospects

Circular RNAs (circRNAs) are a group of covalently closed, endogenous, non‐coding RNAs, which exist widely in human tissues including the heart. Increasing evidence has shown that cardiac circRNAs play crucial regulatory roles in cardiovascular diseases (CVDs). In this review, we aimed to provide a systemic understanding of circRNAs with a special emphasis on the cardiovascular system. We have summarized the current research on the classification, biogenesis and properties of circRNAs as well as their participation in the pathogenesis of CVDs. CircRNAs are conserved, stable and have specific spatiotemporal expression; thus, they have been accepted as a potential diagnostic marker or an incremental prognostic biomarker for CVDs.

What is the impact of human umbilical cord mesenchymal stem cell transplantation on clinical treatment?

Background

Human umbilical cord mesenchymal stem cells (HUC-MSCs) present in the umbilical cord tissue are self-renewing and multipotent. They can renew themselves continuously and, under certain conditions, differentiate into one or more cell types constituting human tissues and organs. HUC-MSCs differentiate, among others, into osteoblasts, chondrocytes, and adipocytes and have the ability to secrete cytokines. The possibility of noninvasive harvesting and low immunogenicity of HUC-MSCs give them a unique advantage in clinical applications. In recent years, HUC-MSCs have been widely used in clinical practice, and some progress has been made in their use for therapeutic purposes.

Main body

This article describes two aspects of the clinical therapeutic effects of HUC-MSCs. On the one hand, it explains the benefits and mechanisms of HUC-MSC treatment in various diseases. On the other hand, it summarizes the results of basic research on HUC-MSCs related to clinical applications. The first part of this review highlights several functions of HUC-MSCs that are critical for their therapeutic properties: differentiation into terminal cells, immune regulation, paracrine effects, anti-inflammatory effects, anti-fibrotic effects, and regulating non-coding RNA. These characteristics of HUC-MSCs are discussed in the context of diabetes and its complications, liver disease, systemic lupus erythematosus, arthritis, brain injury and cerebrovascular diseases, heart diseases, spinal cord injury, respiratory diseases, viral infections, and other diseases. The second part emphasizes the need to establish an HUC-MSC cell bank, discusses tumorigenicity of HUC-MSCs and the characteristics of different in vitro generations of these cells in the treatment of diseases, and provides technical and theoretical support for the clinical applications of HUC-MSCs.

Conclusion

HUC-MSCs can treat a variety of diseases clinically and have achieved good therapeutic effects, and the development of HUC-MSC assistive technology has laid the foundation for its clinical application.

Circular RNAs in Cardiac Regeneration: Cardiac Cell Proliferation, Differentiation, Survival, and Reprogramming

Circular RNAs (circRNAs) are classified as long non-coding RNAs (lncRNAs) that are characterized by a covalent closed-loop structure. This closed-loop shape is the result of a backsplicing event in which the 3' and 5' splice sites are ligated. Through the lack of 3' poly(A) tails and 5' cap structures, circRNAs are more stable than linear RNAs because these adjustments make the circular loop less susceptible to exonucleases. The majority of identified circRNAs possess cell- and tissue-specific expression patterns. In addition, high-throughput RNA-sequencing combined with novel bioinformatics algorithms revealed that circRNA sequences are often conserved across different species suggesting a positive evolutionary pressure. Implicated as regulators of protein turnover, micro RNA (miRNA) sponges, or broad effectors in cell differentiation, proliferation, and senescence, research of circRNA has increased in recent years. Particularly in cardiovascular research, circRNA-related discoveries have opened the door for the development of potential diagnostic and therapeutic tools. Increasing evidence links deviating circRNA expression patterns to various cardiovascular diseases including ischemic heart failure. In this mini-review, we summarize the current state of knowledge on circRNAs in cardiac regeneration with a focus on cardiac cell proliferation, differentiation, cardiomyocyte survival, and cardiac reprogramming.

Differential Regulation of circRNA, miRNA, and piRNA during Early Osteogenic and Chondrogenic Differentiation of Human Mesenchymal Stromal Cells

The goal of the present study is to identify the differential expression of circular RNA (circRNA), miRNA, and piwi-interacting RNA (piRNA) after lineage commitment towards osteo- and chondrogenesis of human bone marrow mesenchymal stromal cells (hMSCs). The cells were maintained for 7 days in either osteogenic or chondrogenic medium. RNA sequencing was performed to assess the expression of miRNA and piRNA, while RNA hybridization arrays were used to identify which circRNA were differentially expressed. qPCR validation of a selection of targets for both osteogenic and chondrogenic differentiation was carried out. The differential expression of several circRNA, miRNA, and piRNA was identified and validated. The expression of total and circular isoforms of FKBP5 was upregulated both in osteo- and chondrogenesis and it was influenced by the presence of dexamethasone. ZEB1, FADS2, and SMYD3 were also identified as regulated in differentiation and/or by dexamethasone. In conclusion, we have identified a set of different non-coding RNAs that are differentially regulated in early osteogenic and chondrogenic differentiation, paving the way for further investigation to understand how dexamethasone controls the expression of those genes and what their function is in MSC differentiation.