miR-335 correlates with senescence/aging in human mesenchymal stem cells and inhibits their therapeutic actions through inhibition of AP-1 activity

Epigenetic mechanisms in stem cell therapies for achilles tendinopathy

Achilles tendinopathy (AT) is a chronic degenerative tendinopathy that affects people's daily lives. Multiple clinical studies have found that current conservative treatments fail to promote quality tendon healing. Recent studies have found that stem cell therapy can target pathophysiological changes in the tendon by replenishing tendon-derived cells, promoting extracellular matrix (ECM) remodeling, and modulating the inflammatory response to improve the microenvironment of Achilles tendon regeneration. And epigenetic modifications play an important role in stem cell fate determination and function. In this review, we provided a brief overview of the biological properties of relevant stem cells. The influence of epigenetic modifications on stem cell proliferation, differentiation, and immune regulatory function in the treatment of AT was also explored. We focused on gene regulatory mechanisms controlled by DNA methylation, histones and non-coding RNAs including microRNAs, circRNAs and long non-coding RNAs. We also discuss the current challenges faced by stem cell therapies in treating AT and their potential solutions. Further research in this area will provide a more comprehensive epigenetic explanation for stem cell therapy for AT, leading to the development of stable, safe and effective stem cell therapies.

Fetal adnexa-derived allogeneic mesenchymal stem cells for cardiac regeneration: the future trend of cell-based therapy for age-related adverse conditions

Heart failure is known as the leading cause of mortality and morbidity in adults, not only in USA but worldwide. Since the world's population is aging, the burden of cardiovascular disorders is increasing. Mesenchymal stem/stromal cells (MSCs) from a patient's bone marrow or other tissues have been widely used as the primary source of stem cells for cellular cardiomyoplasty. The incongruencies that exist between various cell-therapy approaches for cardiac diseases could be attributed to variations in cell processing methods, quality of the process, and cell donors. Off-the-shelf preparations of MSCs, enabled by batch processing of the cells and controlled cell processing factories in regulated facilities, may offer opportunities to overcome these problems. In this study, for the first time, we focused on the fetal membranes and childbirth byproducts as a promising source of cells for regenerative medicine. While many studies have described the advantages of cells derived from these organs, their advantage as a source of younger cells has not been sufficiently covered by the literature. Thus, herein, we highlight challenges that may arise from the impairment of the regenerative capacity of MSCs due to donor age and how allograft cells from fetal adnexa can be a promising substitute for the aged patients' stem cells for myocardial regeneration. Moreover, obstacles to the use of off-the-shelf cell-therapy preparations in regenerative medicine are briefly summarized here.

The Interplay Between Obesity and Aging in Breast Cancer and Regulatory Function of MicroRNAs in This Pathway

Breast cancer (BC) is a significant contributor to cancer-related deaths in women, and it has complex connections with obesity and aging. This review explores the interaction between obesity and aging in relation to the development and progression of BC, focusing on the controlling role of microRNAs (miRNAs). Obesity, characterized by excess adipose tissue, contributes to a proinflammatory environment and metabolic dysregulation, which are important in tumor development. Aging, associated with cellular senescence and systemic changes, further exacerbates these conditions. miRNAs, small noncoding RNAs that regulate gene expression, play key roles in these processes, impacting pathways involved in cell proliferation, apoptosis, and cancer metastasis, either as tumor suppressors or oncogenes. Importantly, specific miRNAs are implicated in mediating the impact of obesity and aging on BC. Exploring the regulatory networks controlled by miRNAs provides valuable information on new targets for therapy and predictive markers, demonstrating the potential for using miRNA-based interventions to treat BC in obese and elderly individuals. This review emphasizes the importance of integrated research strategies to understand the complex connections between obesity, aging, and miRNA regulation in BC.

Suppressing the Aging Phenotype of Mesenchymal Stromal Cells: Are We Ready for Clinical Translation?

Mesenchymal stem/stromal cells (MSCs) are involved in the maintenance and regeneration of a large variety of tissues due to their stemness and multi-lineage differentiation capability. Harnessing these advantageous features, a flurry of clinical trials have focused on MSCs to treat different pathologies, but only few protocols have received regulatory approval so far. Among the various causes hindering MSCs' efficacy is the emergence of cellular senescence, which has been correlated with specific characteristics, such as morphological and epigenetic alterations, DNA damage, ROS production, mitochondrial dysfunction, telomere shortening, non-coding RNAs, loss of proteostasis, and a peculiar senescence-associated secretory phenotype. Several strategies have been investigated for delaying or even hopefully reverting the onset of senescence, as assessed by the senescent phenotype of MSCs. Here, the authors reviewed the most updated literature on the potential causes of senescence, with a particular emphasis on the current and future therapeutic approaches aimed at reverting senescence and/or extending the functional lifespan of stem cells.

miRNAs in the diagnosis and therapy of cardiac and mediastinal tumors: a new dawn for cardio-oncology?

Dysfunctions in miRNA production have been recently investigated as predictors of neoplasms and their therapeutic strategies. In this review, we summarize the available knowledge on miRNAs and cardiac tumors (such as myxoma) and mediastinal tumors (such as thymoma) and propose new avenues for future research. MiRNAs are crucial for cardiac development through the expression of cardiac transcription factors (miR-335-5p), hinder the cell cycle by modulating the activity of transcription factors (miR-126-3p, miR-320a), modulate the production of inflammatory factors such as interleukins (miR-217), and interfere with cell proliferation or apoptosis (miR-218, miR-634 and miR-122). Current and future research on miRNAs is essential, as a deep understanding could lead to a revolution in the field of diagnostics and prevention of neoplastic diseases.

Effects of Replicative Senescence of Human Chorionic MSCs on their EV-miRNA Profile

Chorionic mesenchymal stromal cells (CHO-MSCs) and their extracellular vesicles (EVs) are becoming increasingly popular, since chorion is ethically harmless and an easily accessible source of MSCs. However, until now there is only a limited number of studies with a thorough characterization of CHO-MSCs derived EVs and their miRNA profile. In this study, we monitored changes in the EV-miRNA profile between early and late passage of human CHO-MSCs. First, senescence of CHO-MSCs was induced by serial passaging and confirmed by morphological changes, shortened telomeres and changes in the expression of selected genes. The expression of MSCs-specific surface markers CD73, CD90, CD105 did not change with increasing passages. Next, EVs and their miRNA profiles were compared between early vs late passage cells. Number of EVs and their size were not significantly changed. Seven of the top 10 most expressed EV-miRNAs were common to both early and late passages. A differential expression study between early and late passages identified 37 significantly differentially expressed EV-miRNAs, out of which 23 were found to be associated with pathways of cellular senescence based on KEGG pathway analysis. A set of 9 miRNAs were identified as the most frequently associated with senescence and/or with the most altered expression between early and late passages, out of which miR-145-5p, miR-335-5p and miR-199b-3p were the most significant downregulated miRNAs in late passages. The most upregulated EV-miRNAs were miR-1307-3p, miR-3615 and miR320b. Targeting these miRNAs in future experiments may prolong the therapeutic potential of CHO-MSCs and their EVs.

Mesenchymal Stem Cell Senescence during Aging:From Mechanisms to Rejuvenation Strategies

In cell transplantation therapy, mesenchymal stem cells(MSCs)are ideal seed cells due to their easy acquisition and cultivation, strong regenerative capacity, multi-directional differentiation abilities, and immunomodulatory effects. Autologous MSCs are better applicable compared with allogeneic MSCs in clinical practice. The elderly are the main population for cell transplantation therapy, but as donor aging, MSCs in the tissue show aging-related changes. When the number of generations of in vitro expansion is increased, MSCs will also exhibit replicative senescence. The quantity and quality of MSCs decline during aging, which limits the efficacy of autologous MSCs transplantation therapy. In this review, we examine the changes in MSC senescence as a result of aging, discuss the progress of research on mechanisms and signalling pathways of MSC senescence, and discuss possible rejuvenation strategies of aged MSCs to combat senescence and enhance the health and therapeutic potential of MSCs.

Antioxidant and phytometabolite profiles of ethanolic extract from the cascara pulp of Coffea arabica collected from Gayo Highland: A study for potential anti-photoaging agent

Background: As the most abundant coffee by-product, cascara pulp has been considered a good source of antioxidants which could be used to prevent photoaging. The aim of this study was to determine the phytometabolite profiles, antioxidant and photoaging properties of the ethanolic extract of Coffea arabica cascara pulp. Methods: Ethanolic maceration was performed on the fine powder of C. arabica cascara pulp collected from Gayo Highland, Aceh Province, Indonesia. The filtrate obtained was evaluated for its 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, total phenolic content (TPC), and total flavonoid content (TFC). The phytometabolite profiling was conducted qualitatively using reagents and quantitatively using gas chromatography-mass spectroscopy (GC-MS). The potential of the cascara pulp phytometabolites in inhibiting activator protein-1 (AP-1) was evaluated through molecular docking. Results: The extract had TPC and TFC of 2.04 mg gallic acid equivalent/g extract and 91.81 mg quercetin equivalent/g extract, respectively. The half-maximal inhibitory concentration (IC 50) for the DPPH inhibition reached as low as 9.59 mg/L. Qualitative phytocompound screening revealed the presence of alkaloids, saponins, tannins, flavonoids, steroids, quinones, polyphenols, and triterpenoids. GC-MS revealed the extract containing 5-hydroxy-methylfurfural (22.31%); 2,5-dimethyl-4-hydroxy-3(2H)-furanone (0.74%); and caffeine (21.07%), which could form interaction with AP-1 with binding energies of -172.8, -150.8, and -63.188 kJ/mol, respectively. Conclusion: Ethanolic extract from C. arabica cascara pulp potentially have anti-photoaging properties which is worthy for further investigations in the future.

Knockdown of long noncoding RNA SAN rejuvenates aged adipose-derived stem cells via miR-143-3p/ADD3 axis

BACKGROUND

Senescent adipose-derived stem cells (ASCs) exhibit reduced therapeutic efficacy during wound healing. Transcriptional regulation factors including long noncoding RNAs (lncRNAs) reportedly have essential roles in stem cell aging. However, the mechanisms of which lncRNAs influence mesenchymal stem cell aging and how it works need further investigation.

METHODS

The expression patterns of lncRNA senescence-associated noncoding RNA (SAN) and miR-143-3p in ASCs obtained from old and young volunteer donors were detected by quantitative polymerase chain reaction. ASCs with overexpression or knockdown of SAN and γ-adducin (ADD3) were constructed by lentiviral transduction. Mimic and inhibitor were used to manipulate the cellular level of miR-143-3p in ASCs. The effects of these RNAs on ASCs proliferation, migration and cellular senescence were examined by EdU, transwell and senescence-activated β-galactosidase (SA-β-gal) staining assays. Wound scratch and tube formation assays were conducted to evaluate the capacities of ASCs in promoting fibroblasts migration and endothelial cells angiogenesis. Furthermore, dual-luciferase assays and rescue experiments were performed to identify the RNA interactions. Finally, the therapeutic effects of SAN-depleted aged ASCs were evaluated in a skin injury model.

RESULTS

The lncRNA SAN (NONHSAT035482.2) was upregulated in aged ASCs; it controlled cellular senescence in ASCs. lncRNA SAN knockdown in ASCs led to ASC functional enhancement and the inhibition of cellular senescence; it also promoted the effects of conditioned medium (CM) on endothelial cell tube formation and fibroblast migration. Mechanistic analysis showed that SAN serves as a sponge for miR-143-3p, thereby regulating the expression of ADD3. The application of SAN-depleted aged ASCs increased re-epithelialization, collagen deposition, neovascularization and led to accelerated skin wound closure, compared with transplantation of aged ASCs.

CONCLUSION

The lncRNA SAN mediates ASC senescence by regulating the miR-143-3p/ADD3 pathway, providing a potential target for rejuvenation of senescent ASCs and enhancement of wound repair.

Decreased miR-17-92 cluster correlates with senescence features, disrupted oxidative homeostasis, and impaired therapeutic efficacy of mesenchymal stem cells

Aging and replicative cellular senescence are associated with the reduced therapeutic potential of mesenchymal stem cells (MSCs) on a variety of diseases. This study aimed to determine the mechanism in MSC senescence and further explore a modification strategy to reverse senescence-associated cell dysfunction to improve the therapeutic efficacy of MSCs on acute liver failure (ALF). We found that the adipose tissue-derived MSCs from old mice (oAMSCs) exhibited senescence phenotypes and showed reduced therapeutic efficacy in lipopolysaccharide and D-galactosamine-induced ALF, as shown by the increased hepatic necrosis, liver histology activity index scores, serum liver function indicator levels, and inflammatory cytokine levels. The expression of miR-17-92 cluster members, especially miR-17 and miR-20a, was obviously decreased in oAMSCs and replicatively senescent AMSCs, and was consistent with the decreased oncogene c-Myc level during AMSC senescence and may mediate c-Myc stemness addiction. Further experiments revealed that c-Myc-regulated miR-17-92 expression contributed to increased p21 expression and redox system dysregulation during AMSC senescence. Furthermore, modification of AMSCs with the two key miRNAs in the miR-17-92 cluster mentioned above reversed the senescence features of oAMSCs and restored the therapeutic effect of senescent AMSCs on ALF. In conclusion, the cellular miR-17-92 cluster level is correlated with AMSC senescence and can be used both as an index for evaluating and as a modification target for improving the therapeutic potential of AMSCs.NEW & NOTEWORTHY We reported for the first time that c-Myc-regulated miR-17-92 contributed to increased p21 expression and redox system dysregulation during AMSC senescence and was associated with the reduced therapeutic effects of senescent AMSCs on ALF. Moreover, modifying the expression of the miR-17-92 cluster members, especially miR-17 and/or miR-20a, could reverse AMSC senescence. Thus, miR-17-92 cluster can be used both as an index for evaluating and as a modification strategy for improving the therapeutic potential of AMSCs.

Aged mesenchymal stem cells and inflammation: from pathology to potential therapeutic strategies

Natural ageing of organisms and corresponding age-related diseases result mainly from stem cell ageing and "inflammaging". Mesenchymal stem cells (MSCs) exhibit very high immune-regulating capacity and are promising candidates for immune-related disease treatment. However, the effect of MSC application is not satisfactory for some patients, especially in elderly individuals. With ageing, MSCs undergo many changes, including altered cell population reduction and differentiation ability, reduced migratory and homing capacity and, most important, defective immunosuppression. It is necessary to explore the relationship between the "inflammaging" and aged MSCs to prevent age-related diseases and increase the therapeutic effects of MSCs. In this review, we discuss changes in naturally ageing MSCs mainly from an inflammation perspective and propose some ideas for rejuvenating aged MSCs in future treatments.

Down-regulation of Jun induces senescence through destabilizing chromatin in osteoarthritis chondrocytes

OBJECTIVE

Osteoarthritis (OA) is the most common degenerative joint disease leading to disability worldwide. Cellular senescence is considered to be a fundamental pathogenic mechanism in the development of OA and has attracted increasing attention. However, regulatory mechanisms underlying chondrocyte senescence in OA remain unclear.

METHODS

Bioinformatic methods were used to screen key genes. Immunohistochemistry and the quantitative reverse transcription polymerase chain reaction were used to evaluate gene expression. RNA intervention experiments were performed to explore the functions of key genes.

RESULTS

We used 494 aging-associated genes provided by the Aging Atlas to identify the co-expression modules associated with age and OA. Thirty age-associated differentially expressed genes (ASDEGs) were identified. Using cytoHubba in Cytoscape, we identified Jun as the hub-ASDEG for OA chondrocytes. We confirmed the downregulation of Jun in OA rats and senescent chondrocytes by immunohistochemistry and quantitative reverse transcription polymerase chain reaction, respectively. Inhibition of proliferation and accelerated senescence were observed in chondrocytes treated with siRNA against Jun. Mechanistically, we observed micronuclei formation and reduced expression of H3K9me3 and heterochromatin protein 1gamma in siRNA-Jun-treated chondrocytes, indicating that destabilization of chromatin occurred during this treatment.

CONCLUSION

Jun plays a crucial role in OA development and causes senescence by destabilizing chromatin in chondrocytes. These findings provide new insights into OA progression and suggest promising therapeutic targets.

miRNAs in Cardiac Myxoma: New Pathologic Findings for Potential Therapeutic Opportunities

MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level, contributing to all major cellular processes. The importance of miRNAs in cardiac development, heart function, and valvular heart disease has been shown in recent years, and aberrant expression of miRNA has been reported in various malignancies, such as gastric cancer and breast cancer. Different from other fields of investigation, the role of miRNAs in cardiac tumors still remains difficult to interpret due to the scarcity publications and a lack of narrative focus on this topic. In this article, we summarize the available evidence on miRNAs and cardiac myxomas and propose new pathways for future research. miRNAs play a part in modifying the expression of cardiac transcription factors (miR-335-5p), increasing cell cycle trigger factors (miR-126-3p), interfering with ceramide synthesis (miR-320a), inducing apoptosis (miR-634 and miR-122), suppressing production of interleukins (miR-217), and reducing cell proliferation (miR-218). As such, they have complex and interconnected roles. At present, the study of the complete mechanistic control of miRNA remains a crucial issue, as proper understanding of signaling pathways is essential for the forecasting of therapeutic implications. Other types of cardiac tumors still lack adequate investigation with regard to miRNA. Further research should aim at investigating the causal relationship between different miRNAs and cell overgrowth, considering both myxoma and other histological types of cardiac tumors. We hope that this review will help in understanding this fascinating molecular approach.

miRNA and lncRNA Expression Networks Modulate Cell Cycle and DNA Repair Inhibition in Senescent Prostate Cells

Cellular senescence is a state of permanent growth arrest that arises once cells reach the limit of their proliferative capacity. It creates an inflammatory microenvironment favouring the initiation and progression of various age-related diseases, including prostate cancer. Non-coding RNAs (ncRNAs) have emerged as important regulators of cellular gene expression. Nonetheless, very little is known about the interplay of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) and how deregulation of ncRNA networks promotes cellular senescence. To investigate this, human prostate epithelial cells were cultured through different passages until senescent, and their RNA was extracted and sequenced using RNA sequencing (RNAseq) and microRNA sequencing (miRNA-seq) miRNAseq. Differential expression (DE) gene analysis was performed to compare senescent and proliferating cells with Limma, miRNA-target interactions with multiMiR, lncRNA-target interactions using TCGA data and network evaluation with miRmapper. We found that miR-335-3p, miR-543 and the lncRNAs H19 and SMIM10L2A all play central roles in the regulation of cell cycle and DNA repair processes. Expression of most genes belonging to these pathways were down-regulated by senescence. Using the concept of network centrality, we determined the top 10 miRNAs and lncRNAs, with miR-335-3p and H19 identified as the biggest hubs for miRNAs and lncRNA respectively. These ncRNAs regulate key genes belonging to pathways involved in cell senescence and prostate cancer demonstrating their central role in these processes and opening the possibility for their use as biomarkers or therapeutic targets to mitigate against prostate ageing and carcinogenesis.

The Mechanism of Stem Cell Aging

Stem cells have self-renewal ability and multi-directional differentiation potential. They have tissue repair capabilities and are essential for maintaining the tissue homeostasis. The depletion of stem cells is closely related to the occurrence of body aging and aging-related diseases. Therefore, revealing the molecular mechanisms of stem cell aging will set new directions for the therapeutic application of stem cells, the study of aging mechanisms, and the prevention and treatment of aging-related diseases. This review comprehensively describes the molecular mechanisms related to stem cell aging and provides the basis for further investigations aimed at developing new anti-stem cell aging strategies and promoting the clinical application of stem cells.

Small Noncoding RNAome Changes During Human Bone Marrow Mesenchymal Stem Cells Senescence In Vitro

Bone marrow mesenchymal stem cells (BMSCs) have been used in stem cell-based therapy for various diseases due to their self-renewing ability and differentiation potential to various types of cells and immunoprivileged properties. However, the proliferation capability and functionality of BMSCs are known to decline with aging, which severely limits the extensive applications of BMSC-based therapies. To date, the exact mechanism involved in the cellular senescence of BMSCs remains unclear. RNA is thought to be the initial molecular form of life on earth. It also acts as a transmitter and important regulator of genetic information expression. There are many kinds of small noncoding RNAs with different functions in cells that regulate important life activity processes in multiple dimensions, including development process, gene expression, genomic stability, and cellular senescence. In this study, a replicative senescence model of hBMSCs was established and the expression changes of small noncoding RNAs during senescence were detected by small RNA high-throughput sequencing analysis and qPCR. Small RNA sequencing results showed that there were significant differences in the expression of 203 miRNAs, 46 piRNAs, 63 snoRNAs, 12 snRNAs, and 7 rasiRNAs. The results of qPCR, which was performed for the verification of the sequencing results, showed that there were significant differences in the expression of 24 miRNAs, 34 piRNAs, 34 snoRNAs, and 2 snRNAs. These findings might provide a novel insight into hBMSC senescence and contribute to the development of new targeting senescence strategies.

Key miRNAs in Modulating Aging and Longevity: A Focus on Signaling Pathways and Cellular Targets

Aging is a multifactorial procedure accompanied by gradual deterioration of most biological procedures of cells. MicroRNAs (miRNAs) are a class of short non-coding RNAs that post-transcriptionally regulate the expression of mRNAs through sequence-specific binding, and contributing to many crucial aspects of cell biology. Several miRNAs are expressed differently in various organisms through aging. The function of miRNAs in modulating aging procedures has been disclosed recently with the detection of miRNAs that modulate longevity in the invertebrate model organisms, through the IIS pathway. In these model organisms, several miRNAs have been detected to both negatively and positively regulate lifespan via commonly aging pathways. miRNAs modulate age-related procedures and disorders in different mammalian tissues by measuring their tissue-specific expression in older and younger counterparts, including heart, skin, bone, brain, and muscle tissues. Moreover, several miRNAs have been contributed to modulating senescence in different human cells, and the roles of these miRNAs in modulating cellular senescence have allowed illustrating some mechanisms of aging. The review discusses the available data on miRNAs through the aging process and we highlight the roles of miRNAs as aging biomarkers and regulators of longevity in cellular senescence, tissue aging, and organism lifespan.

Study on potential differentially expressed genes in stroke by bioinformatics analysis

Stroke is a sudden cerebrovascular circulatory disorder with high morbidity, disability, mortality, and recurrence rate, but its pathogenesis and key genes are still unclear. In this study, bioinformatics was used to deeply analyze the pathogenesis of stroke and related key genes, so as to study the potential pathogenesis of stroke and provide guidance for clinical treatment. Gene Expression profiles of GSE58294 and GSE16561 were obtained from Gene Expression Omnibus (GEO), the differentially expressed genes (DEGs) were identified between IS and normal control group. The different expression genes (DEGs) between IS and normal control group were screened with the GEO2R online tool. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the DEGs were performed. Using the Database for Annotation, Visualization and Integrated Discovery (DAVID) and gene set enrichment analysis (GSEA), the function and pathway enrichment analysis of DEGS were performed. Then, a protein–protein interaction (PPI) network was constructed via the Search Tool for the Retrieval of Interacting Genes (STRING) database. Cytoscape with CytoHubba were used to identify the hub genes. Finally, NetworkAnalyst was used to construct the targeted microRNAs (miRNAs) of the hub genes. A total of 85 DEGs were screened out in this study, including 65 upward genes and 20 downward genes. In addition, 3 KEGG pathways, cytokine − cytokine receptor interaction, hematopoietic cell lineage, B cell receptor signaling pathway, were significantly enriched using a database for labeling, visualization, and synthetic discovery. In combination with the results of the PPI network and CytoHubba, 10 hub genes including CEACAM8, CD19, MMP9, ARG1, CKAP4, CCR7, MGAM, CD79A, CD79B, and CLEC4D were selected. Combined with DEG-miRNAs visualization, 5 miRNAs, including hsa-mir-146a-5p, hsa-mir-7-5p, hsa-mir-335-5p, and hsa-mir-27a- 3p, were predicted as possibly the key miRNAs. Our findings will contribute to identification of potential biomarkers and novel strategies for the treatment of ischemic stroke, and provide a new strategy for clinical therapy.

Late/post-term decidual basalis-derived mesenchymal stem/stromal cells show evidence of advanced ageing and downregulation of microRNA-516b-5p

INTRODUCTION

The placenta is a short-lived organ, yet it shows signs of progressive ageing in the third trimester. Studies of ageing chorionic placental tissue have recently flourished, providing evidence of advanced ageing of tissues in the late/post-term (L/PT) period of gestation. However, ageing of the maternal aspect of the maternal-fetal interface, specifically the decidua basalis, is poorly understood. Here, we investigated whether the L/PT period was associated with advanced ageing and exhaustion of important decidua basalis mesenchymal stem/stromal cells (DMSCs) functions.

METHODS

In this study, DMSCs were isolated and characterised from early term (ET) and L/PT placental tissue and they were then investigated by employing various MSC potency and ageing assays. RNA sequencing was also performed to screen for specific microRNAs that are associated with stem cell exhaustion and ageing between ET- and L/PT-DMSCs.

RESULTS

L/PT-DMSCs, when compared to ET-DMSCs, showed significantly lower cell proliferation and a significant higher level of cell apoptosis. L/PT-DMSCs showed significantly lower resistance to oxidative stress and a significant decrease in antioxidant capacity compared with ET-DMSCs. Western blot analysis revealed increased expression of the stress-mediated P-p38MAPK protein in L/PT-DMSCs. RNA Sequencing showed microRNA (miR) miR-516b-5p, was present at significantly lower levels in L/PT-DMSCs. Inhibition of miR-516b-5p in ET-DMSCs revealed a decline in the ability of the inhibited cells to survive in extended cell culture.

DISCUSSION

These data provide the first evidence of advanced ageing and exhaustion of important stem cell functions in L/PT-DMSCs, and the involvement of specific miRs in the DMSC ageing process.

Non-Coding RNAs Steering the Senescence-Related Progress, Properties, and Application of Mesenchymal Stem Cells

The thirst to postpone and even reverse aging progress has never been quenched after all these decades. Unequivocally, mesenchymal stem cells (MSCs), with extraordinary abilities such as self-renewal and multi-directional differentiation, deserve the limelight in this topic. Though having several affable clinical traits, MSCs going through senescence would, on one hand, contribute to age-related diseases and, on the other hand, lead to compromised or even counterproductive therapeutical outcomes. Notably, increasing evidence suggests that non-coding RNAs (ncRNAs) could invigorate various regulatory processes. With even a slight dip or an uptick of expression, ncRNAs would make a dent in or even overturn cellular fate. Thereby, a systematic illustration of ncRNAs identified so far to steer MSCs during senescence is axiomatically an urgent need. In this review, we introduce the general properties and mechanisms of senescence and its relationship with MSCs and illustrate the ncRNAs playing a role in the cellular senescence of MSCs. It is then followed by the elucidation of ncRNAs embodied in extracellular vesicles connecting senescent MSCs with other cells and diversified processes in and beyond the skeletal system. Last, we provide a glimpse into the clinical methodologies of ncRNA-based therapies in MSC-related fields. Hopefully, the intricate relationship between senescence and MSCs will be revealed one day and our work could be a crucial stepping-stone toward that future.

MiR-217 promotes endothelial cell senescence through the SIRT1/p53 signaling pathway

Studies have shown that miR-217 can induce cell senescence, but its mechanism of action in vascular endothelial cell senescence is less reported. Therefore, this study aimed to investigate how miR-217 plays a role in endothelial cell senescence. Human umbilical vein endothelial cells (HUVECs) were used to replicate the aging model, and the population doubling levels (PDLs) during cell passage were counted. Senescence-associated β-galactosidase (SA-β-gal) staining, Real-time quantitative PCR (RT-qPCR), MTT assay, Transwell, and tube formation were used to detect the effects of miR-217 on young and senescent HUVECs. Targetscan7.2 and luciferase assay predicted and verified the relationship between miR-217 and the target gene, and the expression of silent information regulator 1 (SIRT1) and p53 was detected by RT-qPCR and western blot. In addition, SA-β-gal staining detected the effects of miR-217 inhibitor and SIRT1 on senescent HUVECs. MiR-217 was upregulated in senescent endothelial cells. Overexpression of miR-217 promoted the increase of SA-β-gal positive cells, and inhibited proliferation, migration and angiogenesis during endothelial cell growth. Furthermore, SIRT1 was a target gene of miR-217. Simultaneous silencing of SIRT1 reversed the effect of miR-217 inhibitor on the reduction of SA-β-gal positive-staining cells. Our data suggest that overexpression of miR-217 promoted vascular endothelial cell senescence by targeting the SIRT1/p53 signaling pathway, which may provide a new basis for studying the mechanism of action in vascular endothelial cell senescence.

MicroRNAs are critical regulators of senescence and aging in mesenchymal stem cells

MicroRNAs (miRNAs) have recently come under scrutiny for their role in various age-related diseases. Similarly, cellular senescence has been linked to disease and aging. MicroRNAs and senescence likely play an intertwined role in driving these pathologic states. In this review, we present the connection between these two drivers of age-related disease concerning mesenchymal stem cells (MSCs). First, we summarize key miRNAs that are differentially expressed in MSCs and other musculoskeletal lineage cells during senescence and aging. Additionally, we also reviewed miRNAs that are regulated via traditional senescence-associated secretory phenotype (SASP) cytokines in MSC. Lastly, we summarize miRNAs that have been found to target components of the cell cycle arrest pathways inherently activated in senescence. This review attempts to highlight potential miRNA targets for regenerative medicine applications in age-related musculoskeletal disease.

Molecular and Mechanobiological Pathways Related to the Physiopathology of FPLD2

Laminopathies are rare and heterogeneous diseases affecting one to almost all tissues, as in Progeria, and sharing certain features such as metabolic disorders and a predisposition to atherosclerotic cardiovascular diseases. These two features are the main characteristics of the adipose tissue-specific laminopathy called familial partial lipodystrophy type 2 (FPLD2). The only gene that is involved in FPLD2 physiopathology is the LMNA gene, with at least 20 mutations that are considered pathogenic. LMNA encodes the type V intermediate filament lamin A/C, which is incorporated into the lamina meshwork lining the inner membrane of the nuclear envelope. Lamin A/C is involved in the regulation of cellular mechanical properties through the control of nuclear rigidity and deformability, gene modulation and chromatin organization. While recent studies have described new potential signaling pathways dependent on lamin A/C and associated with FPLD2 physiopathology, the whole picture of how the syndrome develops remains unknown. In this review, we summarize the signaling pathways involving lamin A/C that are associated with the progression of FPLD2. We also explore the links between alterations of the cellular mechanical properties and FPLD2 physiopathology. Finally, we introduce potential tools based on the exploration of cellular mechanical properties that could be redirected for FPLD2 diagnosis.

Mesenchymal Stem/Progenitor Cells: The Prospect of Human Clinical Translation

Mesenchymal stem/progenitor cells (MSCs) are key players in regenerative medicine, relying principally on their differentiation/regeneration potential, immunomodulatory properties, paracrine effects, and potent homing ability with minimal if any ethical concerns. Even though multiple preclinical and clinical studies have demonstrated remarkable properties for MSCs, the clinical applicability of MSC-based therapies is still questionable. Several challenges exist that critically hinder a successful clinical translation of MSC-based therapies, including but not limited to heterogeneity of their populations, variability in their quality and quantity, donor-related factors, discrepancies in protocols for isolation, in vitro expansion and premodification, and variability in methods of cell delivery, dosing, and cell homing. Alterations of MSC viability, proliferation, properties, and/or function are also affected by various drugs and chemicals. Moreover, significant safety concerns exist due to possible teratogenic/neoplastic potential and transmission of infectious diseases. Through the current review, we aim to highlight the major challenges facing MSCs' human clinical translation and shed light on the undergoing strategies to overcome them.

Effects of cryopreservation and long-term culture on biological characteristics and proteomic profiles of human umbilical cord-derived mesenchymal stem cells

BACKGROUND

Human umbilical cord-derived MSCs (hUC-MSCs) have been identified as promising seeding cells in tissue engineering and clinical applications of regenerative medicine due to their advantages of simple acquisition procedure and the capability to come from a young tissue donor over the other MSCs sources. In clinical applications, large scale production is required and optimal cryopreservation and culture conditions are essential to autologous and allogeneic transplantation in the future. However, the influence of cryopreserved post-thaw and long-term culture on hUC-MSCs remains unknown, especially in terms of specific protein expression. Therefore, biological characteristics and proteomic profiles of hUC-MSCs after cryopreserving and long-term culturing were investigated.

METHODS

Firstly, hUC-MSCs were isolated from human umbilical cord tissues and identified through morphology, surface markers and tri-lineage differentiation potential at passage 3, and then the biological characteristics and proteomic profiles were detected and compared after cryopreserving and long-term culturing at passage 4 and continuously cultured to passage 10 with detection occurring here as well. The proteomic profiles were tested by using the isobaric tags for relative and absolute quantification (iTRAQ) labeling technique and differential protein were confirmed by mass spectrometry.

RESULTS

The results showed no significant differences in phenotypes including morphology, surface marker and tri-lineage differentiation potential but have obvious changes in translation level, which is involved in metabolism, cell cycle and other pathways.

CONCLUSION

This suggests that protein expression may be used as an indicator of hUC-MSCs security testing before applying in clinical settings, and it is also expected to provide the foundation or standardization guide of hUC-MSCs applications in regenerative medicine.

Stem Cell Senescence: the Obstacle of the Treatment of Degenerative Disk Disease

Intervertebral disc (IVD) has a pivotal role in the maintenance of flexible motion. IVD degeneration is one of the primary causes of low back pain and disability, which seriously influences patients' health, and increases the family and social economic burden. Recently, stem cell therapy has been proven to be more effective on IVD degeneration disease. However, stem cell senescence is the limiting factor in the IVD degeneration treatment. Senescent stem cells have a negative effect on the self-repair on IVD degeneration. In this review, we delineate that the factors such as telomerase shortening, DNA damage, oxidative stress, microenvironment and exosomes will induce stem cell aging. Recent studies tried to delay the aging of stem cells by regulating the expression of aging-related genes and proteins, changing the activity of telomerase, improving the survival microenvironment of stem cells and drug treatment. Understanding the mechanism of stem cell aging and exploring new approaches to delay or reverse stem cell aging asks for research on the repair of the degenerated disc.

miR-155-5p inhibition rejuvenates aged mesenchymal stem cells and enhances cardioprotection following infarction

Aging impairs the functions of human mesenchymal stem cells (MSCs), thereby severely reducing their beneficial effects on myocardial infarction (MI). MicroRNAs (miRNAs) play crucial roles in regulating the senescence of MSCs; however, the underlying mechanisms remain unclear. Here, we investigated the significance of miR-155-5p in regulating MSC senescence and whether inhibition of miR-155-5p could rejuvenate aged MSCs (AMSCs) to enhance their therapeutic efficacy for MI. Young MSCs (YMSCs) and AMSCs were isolated from young and aged donors, respectively. The cellular senescence of MSCs was evaluated by senescence-associated β-galactosidase (SA-β-gal) staining. Compared with YMSCs, AMSCs exhibited increased cellular senescence as evidenced by increased SA-β-gal activity and decreased proliferative capacity and paracrine effects. The expression of miR-155-5p was much higher in both serum and MSCs from aged donors than young donors. Upregulation of miR-155-5p in YMSCs led to increased cellular senescence, whereas downregulation of miR-155-5p decreased AMSC senescence. Mechanistically, miR-155-5p inhibited mitochondrial fission and increased mitochondrial fusion in MSCs via the AMPK signaling pathway, thereby resulting in cellular senescence by repressing the expression of Cab39. These effects were partially reversed by treatment with AMPK activator or mitofusin2-specific siRNA (Mfn2-siRNA). By enhancing angiogenesis and promoting cell survival, transplantation of anti-miR-155-5p-AMSCs led to improved cardiac function in an aged mouse model of MI compared with transplantation of AMSCs. In summary, our study shows that miR-155-5p mediates MSC senescence by regulating the Cab39/AMPK signaling pathway and miR-155-5p is a novel target to rejuvenate AMSCs and enhance their cardioprotective effects.

Immunoregulatory properties of mesenchymal stem cells: Micro-RNAs

Mesenchymal stem cells (MSCs) are multipotent cells that are excellent candidates for different cellular therapies due to their physiological properties such as immunoregulatory function. whetheare currently utilized for regenerative medication and treatment of a number of inflammatory illnesses given their ability to considerably impact tissue microenvironments via extracellular vesicles or toll-like receptor pathway modulation. MicroRNAs (miRNAs) are small noncoding RNAs that target the messenger RNA and play a critical role in different biological procedures, such as the development and reaction of the immune system. Moreover, miRNAs have recently been revealed to have serious functions in MSCs to regulate immunomodulatory properties. In this review, we study how the miRNAs pathway can modulate the immunoregulatory activity of MSCs by counting their interactions with immune cells and also discuss the possibility of using miRNA-based implications for MSC-based therapies.

Emerging role of stem cell-derived extracellular microRNAs in age-associated human diseases and in different therapies of longevity

Organismal aging involves the progressive decline in organ function and increased susceptibility to age-associated diseases. This has been associated with the aging of stem cell populations within the body that decreases the capacity of stem cells to self-renew, differentiate, and regenerate damaged tissues and organs. This review aims to explore how aging is associated with the dysregulation of stem cell-derived extracellular vesicles (SCEVs) and their corresponding miRNA cargo (SCEV-miRNAs), which are short non-coding RNAs involved in post-transcriptional regulation of target genes. Recent evidence has suggested that in aging stem cells, SCEV-miRNAs may play a vital role regulating various processes that contribute to aging: cellular senescence, stem cell exhaustion, telomere length, and circadian rhythm. Hence, further clarifying the age-dependent molecular mechanisms through which SCEV-miRNAs exert their downstream effects may inform a greater understanding of the biology of aging, elucidate their role in stem cell function, and identify important targets for future regenerative therapies. Additionally, current studies evaluating therapeutic role of SCEVs and SCEV-miRNAs in treating several age-associated diseases are also discussed.

Two-stage Bayesian GWAS of 9576 individuals identifies SNP regions that are targeted by miRNAs inversely expressed in Alzheimer's and cancer

INTRODUCTION

We compared genetic variants between Alzheimer's disease (AD) and two age-related cancers-breast and prostate -to identify single-nucleotide polymorphisms (SNPs) that are associated with inverse comorbidity of AD and cancer.

METHODS

Bayesian multinomial regression was used to compare sex-stratified cases (AD and cancer) against controls in a two-stage study. A ±500 KB region around each replicated hit was imputed and analyzed after merging individuals from the two stages. The microRNAs (miRNAs) that target the genes involving these SNPs were analyzed for miRNA family enrichment.

RESULTS

We identified 137 variants with inverse odds ratios for AD and cancer located on chromosomes 19, 4, and 5. The mapped miRNAs within the network were enriched for miR-17 and miR-515 families.

DISCUSSION

The identified SNPs were rs4298154 (intergenic), within TOMM40/APOE/APOC1, MARK4, CLPTM1, and near the VDAC1/FSTL4 locus. The miRNAs identified in our network have been previously reported to have inverse expression in AD and cancer.

Upregulation of miR-335-3p by NF-κB Transcriptional Regulation Contributes to the Induction of Pulmonary Arterial Hypertension via APJ during Hypoxia

Pulmonary arterial hypertension (PAH) is a cardiopulmonary disease that can lead to heart failure and eventually death. MicroRNAs (miRs) play essential roles during PAH progression; however, their exact mechanism of action remains unclear. Apelin is a small bioactive peptide with a key protective function in the pathogenesis of PAH mediated by binding to the APJ gene. The aim of the present study was to investigate the role of miR-335-3p in chronic normobaric hypoxia (CNH)-induced PAH in mice and the potential underlying regulatory mechanism. Adult male C57BL/6 mice were exposed to normoxia (~21% O₂) or CNH (~10% O₂, 23 h/d) for 5 weeks. MiR-335-3p was significantly increased in lung tissue of CNH-induced PAH mice. Blocking miR-335-3p attenuated CNH-induced PAH and alleviated pulmonary vascular remodeling. Bioinformatics analysis and luciferase reporter assay indicated that nuclear factor-kappa beta (NF-κB) acted as a transcriptional regulator upstream of miR-335-3p. Pyrrolidine dithiocarbamate treatment reversed the CNH-induced increase in miR-335-3p expression and diminished CNH-induced PAH. Moreover, p50^-/- mice were resistant to CNH-induced PAH. Finally, APJ was identified as a direct targeting gene downstream of miR-335-3p, and pharmacological activation of APJ by its ligand apelin-13 reduced CNH-induced PAH and improved pulmonary vascular remodeling. Our results indicate that NF-κB-mediated transcriptional upregulation of miR-335-3p contributes to the inhibition of APJ and induction of PAH during hypoxia; hence, miR-335-3p could be a potential therapeutic target for hypoxic PAH.

Autophagy inhibits the mesenchymal stem cell aging induced by D-galactose through ROS/JNK/p38 signalling

Autophagy and cellular senescence are two critical responses of mammalian cells to stress and may have a direct relationship given that they respond to the same set of stimuli, including oxidative stress, DNA damage, and telomere shortening. Mesenchymal stem cells (MSCs) have emerged as reliable cell sources for stem cell transplantation and are currently being tested in numerous clinical trials. However, the effects of autophagy on MSC senescence and corresponding mechanisms have not been fully evaluated. Several studies demonstrated that autophagy level increases in aging MSCs and the downregulation of autophagy can delay MSC senescence, which is inconsistent with most studies that showed autophagy could play a protective role in stem cell senescence. To further study the relationship between autophagy and MSC senescence and explore the effects and mechanisms of premodulated autophagy on MSC senescence, we induced the up- or down-regulation of autophagy by using rapamycin (Rapa) or 3-methyladenine, respectively, before MSC senescence induced by D-galactose (D-gal). Results showed that pretreatment with Rapa for 24 hours remarkably alleviated MSC aging induced by D-gal and inhibited ROS generation. p-Jun N-terminal kinases (JNK) and p-38 expression were also clearly decreased in the Rapa group. Moreover, the protective effect of Rapa on MSC senescence can be abolished by enhancing the level of ROS, and p38 inhibitor can reverse the promoting effect of H₂ O₂ on MSC senescence. In summary, the present study indicates that autophagy plays a protective role in MSC senescence induced by D-gal, and ROS/JNK/p38 signalling plays an important mediating role in autophagy-delaying MSC senescence.

The Role of CDR1as in Proliferation and Differentiation of Human Umbilical Cord-Derived Mesenchymal Stem Cells

Mesenchymal stem cells derived from human umbilical cord (hucMSCs) are considered a promising tool for regenerative medicine. circRNAs as newly discovered noncoding RNAs are involved in multiple biological processes. However, little has been known about the function of circRNAs in the proliferation and differentiation of hucMSCs. In this study, we selected several circRNAs expressed in MSCs from circBase and found that CDR1as expression level was markedly significant. We observed that, compared with that of uninduced hucMSCs, the CDR1as expression level of induced hucMSCs decreased with cell induction differentiation. By using siRNA to knock down CDR1as of hucMSCs, we discovered that proliferation was inhibited but the apoptosis increased. In addition, we found that the expression of stemness transcription factors (STFs) was downregulated after CDR1as knockdown and the adipogenesis and osteogenesis potential of hucMSCs was impaired. Our findings suggest that CDR1as takes a part in maintaining proliferation and differentiation of hucMSCs, providing clues for MSC modification and further for stem cell therapy and tissue regeneration.

MicroRNA expression profile in retina and choroid in oxygen-induced retinopathy model

Background

Ischemic retinopathies (IRs) are leading causes of visual impairment. They are characterized by an initial phase of microvascular degeneration and a second phase of aberrant pre-retinal neovascularization (NV). microRNAs (miRNAs) regulate gene expression, and a number play a role in normal and pathological NV. But, post-transcriptional modulation of miRNAs in the eye during the development of IRs has not been systematically evaluated.

Aims & methods

Using Next Generation Sequencing (NGS) we profiled miRNA expression in the retina and choroid during vasodegenerative and NV phases of oxygen-induced retinopathy (OIR).

Results

Approximately 20% of total miRNAs exhibited altered expression (up- or down-regulation); 6% of miRNA were found highly expressed in retina and choroid of rats subjected to OIR. During OIR-induced vessel degeneration phase, miR-199a-3p, -199a-5p, -1b, -126a-3p displayed a robust decreased expression (> 85%) in the retina. While in the choroid, miR-152-3p, -142-3p, -148a-3p, -532-3p were upregulated (>200%) and miR-96-5p, -124-3p, -9a-3p, -190b-5p, -181a-1-3p, -9a-5p, -183-5p were downregulated (>70%) compared to controls. During peak pathological NV, miR-30a-5p, -30e-5p and 190b-5p were markedly reduced (>70%), and miR-30e-3p, miR-335, -30b-5p strongly augmented (by up to 300%) in the retina. Whereas in choroid, miR-let-7f-5p, miR-126a-5p and miR-101a-3p were downregulated by (>81%), and miR-125a-5p, let-7e-5p and let-7g-5p were upregulated by (>570%) during NV. Changes in miRNA observed using NGS were validated using qRT-PCR for the 24 most modulated miRNAs. In silico approach to predict miRNA target genes (using algorithms of miRSystem database) identified potential new target genes with pro-inflammatory, apoptotic and angiogenic properties.

Conclusion

The present study is the first comprehensive description of retinal/choroidal miRNAs profiling in OIR (using NGS technology). Our results provide a valuable framework for the characterization and possible therapeutic potential of specific miRNAs involved in ocular IR-triggered inflammation, angiogenesis and degeneration.

Bone marrow mesenchymal stem cells: Aging and tissue engineering applications to enhance bone healing

Bone has well documented natural healing capacity that normally is sufficient to repair fractures and other common injuries. However, the properties of bone change throughout life, and aging is accompanied by increased incidence of bone diseases and compromised fracture healing capacity, which necessitate effective therapies capable of enhancing bone regeneration. The therapeutic potential of adult mesenchymal stem cells (MSCs) for bone repair has been long proposed and examined. Actions of MSCs may include direct differentiation to become bone cells, attraction and recruitment of other cells, or creation of a regenerative environment via production of trophic growth factors. With systemic aging, MSCs also undergo functional decline, which has been well investigated in a number of recent studies. In this review, we first describe the changes in MSCs during aging and discuss how these alterations can affect bone regeneration. We next review current research findings on bone tissue engineering, which is considered a promising and viable therapeutic solution for structural and functional restoration of bone. In particular, the importance of MSCs and bioscaffolds is highlighted. Finally, potential approaches for the prevention of MSC aging and the rejuvenation of aged MSC are discussed.

Micro-RNA335-5p targeted inhibition of sKlotho and promoted oxidative stress–mediated aging of endothelial cells

Aim: MiR-335-5p expression might induce endothelial cells (ECs) aging and target inhibit sKlotho. This study aimed to investigate whether oxidative stress evoked miR-335-5p expression and whether miR-335-5p-regulated ECs function through sKlotho. Methods: The expression of miR-335-5p was detected in human umbilical vein endothelial cells treated with H2O2. Subsequently, endothelial function and sKlotho expression were measured in human umbilical vein endothelial cells treated with H2O2 and transfected with miR-335-5p mimics or inhibitor sequences. Vector containing reporting system of sKlotho3′- untranslated region with a miR-335-5p-binding site was constructed. Results: H2O2 stimulation significantly increased miR-335-5p expression. Force overexpression miR-335-5p suppress ECs function and sKlotho expression. MiR-335-5p target regulated sKlotho. Conclusion: MiR-335-5p might serve as a negative factor for endothelial homeostasis and a potential treatment target for atherosclerosis.

MicroRNA controls of cellular senescence

Cellular senescence is a state of permanent cell-cycle arrest triggered by different internal and external stimuli. This phenomenon is considered to be both beneficial and detrimental depending on the cell types and biological contexts. During normal embryonic development and after tissue injury, cellular senescence is critical for tissue remodeling. In addition, this process is useful for arresting growth of tumor cells, particularly during early onset of tumorigenesis. However, accumulation of senescent cells decreases tissue regenerative capabilities and induces inflammation, which is responsible for cancer and organismal aging. Therefore cellular senescence has to be tightly regulated, and dysregulation might lead to the aging and human diseases. Among many regulators of cellular senescence, in this review, I will focus on microRNAs, small non-coding RNAs playing critical roles in diverse biological events including cellular senescence. [BMB Reports 2018; 51(10): 494-500].

Ell3 functions as a critical decision maker at the crossroad between stem cell senescence and apoptosis

Background

Ell3 is a RNA polymerase II elongation factor that has various cell type-dependent functions, such as regulating the differentiation efficiency of embryonic stem cells and sensitizing cancer cells to anticancer drugs. However, there has been little research on the role of Ell3 on the regulation of senescence and apoptosis of stem cells.

Methods

We analyzed the senescence of Ell3-suppressed stem cells by mitochondrial activity, β-gal (+) cells, and lineage differentiation efficiency. The apoptosis of Ell3-overexpressing stem cells was analyzed by Annexin V staining, Immunoblot, and Live&dead assay. In addition, chromatin immunoprecipitation and luciferase assays were used to demonstrate p53 functions as a direct transcriptional activator of Ell3.

Results

Suppression of Ell3 expression induced senescence in stem cells by increasing Bcl-2 expression. Unlike the effect of Ell3 suppression, the ectopic expression of Ell3 induces apoptosis of stem cells and induces apoptosis of adjacent cells. In addition, p53 functions as a direct transcriptional activator of Ell3 during the stem cell apoptosis.

Conclusions

We suggest that the function of Ell3 is associated with the p53-Bcl2 axis in both senescent and apoptotic ADSCs.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1137-9) contains supplementary material, which is available to authorized users.

MiR-1292 Targets FZD4 to Regulate Senescence and Osteogenic Differentiation of Stem Cells in TE/SJ/Mesenchymal Tissue System via the Wnt/β-catenin Pathway

With the expansion of the elderly population, age-related osteoporosis and the resulting bone loss have become a significant health and socioeconomic issue. In Triple Energizer (TE)/San Jiao (SJ)/mesenchymal tissue system, mesenchymal stem cell (MSC) senescence, and impaired osteogenesis are thought to contribute to age-related diseases such as osteoporosis. Therefore, comprehending the molecular mechanisms underlying MSC senescence and osteogenesis is essential to improve the treatment of bone metabolic diseases. With the increasing role of miRNAs in MSC aging and osteogenic differentiation, we need to understand further how miRNAs participate in relevant mechanisms. In this study, we observed that the expression of miR-1292 was augmented during cellular senescence and lessened with osteogenesis in human adipose-derived mesenchymal stem cells (hADSCs). miR-1292 expression was positively correlated with senescence markers and negatively associated with bone formation markers in clinical bone samples. Overexpression of miR-1292 notably accelerated hADSC senescence and restrained osteogenesis, whereas its knockdown decreased senescence and enhanced osteogenic differentiation. Furthermore, miR-1292 upregulation inhibited ectopic bone formation in vivo. Mechanistically, FZD4 was identified as a potential target of miR-1292. Downregulation of FZD4 phenocopied the effect of miR-1292 overexpression on hADSC senescence and osteogenic differentiation. Moreover, the impact of miR-1292 suppression on senescence and osteogenesis were reversed by the FZD4 knockdown. Pathway analysis revealed that miR-1292 regulates hADSC senescence and osteogenesis through the Wnt/β-catenin signaling pathway. Thus, TE/SJ/mesenchymal tissue system is the largest organ composed of various functional cells derived from mesoderm, responsible for maintaining homeostasis and regulating cell senescence. miR-1292 might serve as a novel therapeutic target for the prevention and treatment of osteoporosis or other diseases related to bone metabolism and aging.

The Emerging Roles of microRNAs in Stem Cell Aging

Aging is the continuous loss of tissue and organ function over time. MicroRNAs (miRNAs) are thought to play a vital role in this process. miRNAs are endogenous small noncoding RNAs that control the expression of target mRNA. They are involved in many biological processes such as developmental timing, differentiation, cell death, stem cell proliferation and differentiation, immune response, aging and cancer. Accumulating studies in recent years suggest that miRNAs play crucial roles in stem cell division and differentiation. In the present chapter, we present a brief overview of these studies and discuss their contributions toward our understanding of the importance of miRNAs in normal and aged stem cell function in various model systems.

Oxidative Stress in Mesenchymal Stem Cell Senescence: Regulation by Coding and Noncoding RNAs

SIGNIFICANCE

Mesenchymal stem cells (MSCs), adult stem cells with the potential of differentiation into mesodermal lineages, play an important role in tissue homeostasis and regeneration. In different organs, a subpopulation of MSCs is located near the vasculature and possibly represents the original source of lineage-committed mesenchymal progenitors. Recent Advances: The plasticity and immune characteristics of MSCs render them a preferential tool for regenerative cell therapy.

CRITICAL ISSUES

The culture expansion needed before MSC transplantation is associated with cellular senescence. Moreover, accelerated senescence of the total and perivascular MSC pool has been observed in humans and mouse models of premature aging disorders. MSC dysfunction is acknowledged as a culprit for the aging-associated degeneration of mesodermal tissues, but the underlying epigenetic pathways remain elusive. This article reviews current understanding of mechanisms impinging on MSC health, including oxidative stress, Nrf2-antioxidant responsive element activity, sirtuins, noncoding RNAs, and PKCs.

FUTURE DIRECTIONS

We provide evidence that epigenetic profiling of MSCs is utilitarian to the prediction of therapeutic outcomes. In addition, strategies that target oxidative stress-associated mechanisms represent promising approaches to counteract the detrimental effect of age and senescence in MSCs.-Antioxid. Redox Signal. 29, 864-879.

Identity, proliferation capacity, genomic stability and novel senescence markers of mesenchymal stem cells isolated from low volume of human bone marrow

Human bone marrow mesenchymal stem cells (hBM-MSCs) hold promise for treating incurable diseases and repairing of damaged tissues. However, hBM-MSCs face the disadvantages of painful invasive isolation and limited cell numbers. In this study we assessed characteristics of MSCs isolated from residual human bone marrow transplantation material and expanded to clinically relevant numbers at passages 3-4 and 6-7. Results indicated that early passage hBM-MSCs are genomically stable and retain identity and high proliferation capacity. Despite the chromosomal stability, the cells became senescent at late passages, paralleling the slower proliferation, altered morphology and immunophenotype. By qRT-PCR array profiling, we revealed 13 genes and 33 miRNAs significantly differentially expressed in late passage cells, among which 8 genes and 30 miRNAs emerged as potential novel biomarkers of hBM-MSC aging. Functional analysis of genes with altered expression showed strong association with biological processes causing cellular senescence. Altogether, this study revives hBM as convenient source for cellular therapy. Potential novel markers provide new details for better understanding the hBM-MSC senescence mechanisms, contributing to basic science, facilitating the development of cellular therapy quality control, and providing new clues for human disease processes since senescence phenotype of the hematological patient hBM-MSCs only very recently has been revealed.

A miR-335/COX-2/PTEN axis regulates the secretory phenotype of senescent cancer-associated fibroblasts

Senescent cancer-associated fibroblasts (CAF) develop a senescence-associated secretory phenotype (SASP) that is believed to contribute to cancer progression. The mechanisms underlying SASP development are, however, poorly understood. Here we examined the functional role of microRNA in the development of the SASP in normal fibroblasts and CAF. We identified a microRNA, miR-335, up-regulated in the senescent normal fibroblasts and CAF and able to modulate the secretion of SASP factors and induce cancer cell motility in co-cultures, at least in part by suppressing the expression of phosphatase and tensin homologue (PTEN). Additionally, elevated levels of cyclo-oxygenase 2 (PTGS2; COX-2) and prostaglandin E2 (PGE2) secretion were observed in senescent fibroblasts, and inhibition of COX-2 by celecoxib reduced the expression of miR-335, restored PTEN expression and decreased the pro-tumourigenic effects of the SASP. Collectively these data demonstrate the existence of a novel miRNA/PTEN-regulated pathway modulating the inflammasome in senescent fibroblasts.

MicroRNA signature in the chemoprevention of functionally-enriched stem and progenitor pools (FESPP) by Active Hexose Correlated Compound (AHCC)

PURPOSE

Many breast cancer patients use natural compounds in their battle against breast cancer. Active Hexose Correlated Compound (AHCC®) is a cultured mushroom mycelium extract shown to favorably modulate the immune system and alleviate cancer burden. Cancer Stem cells (CSCs) are a subset of highly tumorigenic cancer cells that are thought to be responsible for recurrence. CSCs can be epigenetically regulated by microRNAs (miRNAs). We hypothesized that AHCC may influence CSCs by modulating tumor-suppressor or oncogenic miRNAs.

METHODS

Functionally-enriched stem and progenitor pools (FESPP) were isolated in the form of mammospheres from MDA-MB-231, MCF-7, and 4T1 cells, exposed to AHCC in both regular and primary culture from Balb/c mice, and analyzed by visual counting and flow cytometry. Cell motility was also observed in MDA-MB-231 cells. Profiling and RT-qPCR were performed to determine AHCC influence on miRNAs in MDA-MB-231 mammospheres. Additionally, Balb/c mice were orally gavaged with AHCC, and tumor growth parameters and miR-335 expression were analyzed. MDA-MB-231 cells were transfected with miR-335 and analyzed by western blot.

RESULTS

We demonstrated that AHCC reduced mammosphere growth in three cell lines and in primary culture, prevented cell migration, and upregulated miR-335 expression in MDA-MB-231 cells and mouse tumor samples. Among the differentially regulated miRNAs in CSCs, we focused on tumor suppressor miR-335, known to target extracellular matrix protein Tenascin C (TNC). TNC is involved in CSC immune evasion pathways. In MDA-MB-231, inhibition of miR-335 increased TNC protein expression.

CONCLUSIONS

These results support that AHCC limits FESPP growth, partly by targeting miRNA pathways.

Reduced neuroprotective potential of the mesenchymal stromal cell secretome with ex vivo expansion, age and progressive multiple sclerosis

BACKGROUND

Clinical trials using ex vivo expansion of autologous mesenchymal stromal cells (MSCs) are in progress for several neurological diseases including multiple sclerosis (MS). Given that environment alters MSC function, we examined whether in vitro expansion, increasing donor age and progressive MS affect the neuroprotective properties of the MSC secretome.

METHODS

Comparative analyses of neuronal survival in the presence of MSC-conditioned medium (MSCcm) isolated from control subjects (C-MSCcm) and those with MS (MS-MSCcm) were performed following (1) trophic factor withdrawal and (2) nitric oxide-induced neurotoxicity.

RESULTS

Reduced neuronal survival following trophic factor withdrawal was seen in association with increasing expansion of MSCs in vitro and MSC donor age. Controlling for these factors, there was an independent, negative effect of progressive MS. In nitric oxide neurotoxicity, MSCcm-mediated neuroprotection was reduced when C-MSCcm was isolated from higher-passage MSCs and was negatively associated with increasing MSC passage number and donor age. Furthermore, the neuroprotective effect of MSCcm was lost when MSCs were isolated from patients with MS.

DISCUSSION

Our findings have significant implications for MSC-based therapy in neurodegenerative conditions, particularly for autologous MSC therapy in MS. Impaired neuroprotection mediated by the MSC secretome in progressive MS may reflect reduced reparative potential of autologous MSC-based therapy in MS and it is likely that the causes must be addressed before the full potential of MSC-based therapy is realized. Additionally, we anticipate that understanding the mechanisms responsible will contribute new insights into MS pathogenesis and may also be of wider relevance to other neurodegenerative conditions.