Expansion induced microRNA changes in bone marrow mesenchymal stromal cells reveals interplay between immune regulation and cell cycle

Discovery and validation of Hsa-microRNA-3665 promoter methylation as a potential biomarker for the prognosis of esophageal squaous cell carcinoma

BACKGROUND

Methylation of microRNA (miRNA) promoters associated with diseases is a common epigenetic mechanism in the development of various human cancers. However, its relationship with prognosis in esophageal squamous cell carcinoma (ESCC) remains unclear. This study aims to explore the association between the methylation level of has-miR-3665 promoter and prognosis in ESCC.

METHODS

Human miRNA data were downloaded from miRbase, and we identified CpG islands of these human miRNAs by genomics browser analysis. MiRNA methylation levels were detected by methylation-specific high-resolution melting. Gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to explore the molecular mechanism of hsa-miR-3665. Cox regression analysis was used to investigate prognostic factors. The overall survival rate was predicted by a nomogram.

RESULTS

We found that 88 human miRNAs had promoter methylatio, of which 15 miRNAs were found to be epigenetically regulated in ESCC cells compared with their normal counterparts, including hsa-miR-3665. Meanwhile, hsa-miR-3665 expression was significantly lower in ESCC tumour tissue than in adjacent tissue (P = 0.03). GO and KEGG analyses demonstrated that the target genes are involved in protein transport, transcription regulator activity, MAPK and RAS signaling pathway. High hsa-miR-3665 promoter methylation levels were associated with a poor prognosis (HR = 3.89, 95% CI 1.11 ~ 13.55). Moreover, a nomogram incorporating the hsa-miR-3665 methylation level and clinical factors presented a good performance for predicting survival in the training and validation tests, with C-indices of 0.748 and 0.751, respectively.

CONCLUSIONS

High hsa-miR-3665 promoter methylation levels may be a potential biomarker for the progression of ESCC.

Rejuvenation of Mesenchymal Stem Cells to Ameliorate Skeletal Aging

Advanced age is a shared risk factor for many chronic and debilitating skeletal diseases including osteoporosis and periodontitis. Mesenchymal stem cells develop various aging phenotypes including the onset of senescence, intrinsic loss of regenerative potential and exacerbation of inflammatory microenvironment via secretory factors. This review elaborates on the emerging concepts on the molecular and epigenetic mechanisms of MSC senescence, such as the accumulation of oxidative stress, DNA damage and mitochondrial dysfunction. Senescent MSCs aggravate local inflammation, disrupt bone remodeling and bone-fat balance, thereby contributing to the progression of age-related bone diseases. Various rejuvenation strategies to target senescent MSCs could present a promising paradigm to restore skeletal aging.

Cellular expansion of MSCs: Shifting the regenerative potential

Mesenchymal-derived stromal or progenitor cells, commonly called "MSCs," have attracted significant clinical interest for their remarkable abilities to promote tissue regeneration and reduce inflammation. Recent studies have shown that MSCs' therapeutic effects, originally attributed to the cells' direct differentiation capacity into the tissue of interest, are largely driven by the biomolecules the cells secrete, including cytokines, chemokines, growth factors, and extracellular vesicles containing miRNA. This secretome coordinates upregulation of endogenous repair and immunomodulation in the local microenvironment through crosstalk of MSCs with host tissue cells. Therapeutic applications for MSCs and their secretome-derived products often involve in vitro monolayer expansion. However, consecutive passaging of MSCs significantly alters their therapeutic potential, inducing a broad shift from a pro-regenerative to a pro-inflammatory phenotype. A consistent by-product of in vitro expansion of MSCs is the onset of replicative senescence, a state of cell arrest characterized by an increased release of proinflammatory cytokines and growth factors. However, little is known about changes in the secretome profile at different stages of in vitro expansion. Some culture conditions and bioprocessing techniques have shown promise in more effectively retaining the pro-regenerative and anti-inflammatory MSC phenotype throughout expansion. Understanding how in vitro expansion conditions influence the nature and function of MSCs, and their associated secretome, may provide key insights into the underlying mechanisms driving these alterations. Elucidating the dynamic and diverse changes in the MSC secretome at each stage of in vitro expansion is a critical next step in the development of standardized, safe, and effective MSC-based therapies.

Identification of Six N7-Methylguanosine-Related miRNA Signatures to Predict the Overall Survival and Immune Landscape of Triple-Negative Breast Cancer through In Silico Analysis

Triple-negative breast cancer (TNBC) is a widely prevalent breast cancer, with a mortality rate of up to 25%. TNBC has a lower survival rate, and the significance of N7-methylguanosine (m7G) modification in TNBC remains unclear. Thus, this study is aimed at investigating m7G-related miRNAs in TNBC patients through in silico analysis. In our research, RNA sequencing and clinical data were obtained from The Cancer Genome Atlas (TCGA) database. The miRNAs targeting typical m7G modification regulators Methyltransferase-like 1 (METTL1) and WD repeat domain 4 (WDR4) were predicted on the TargetScan website. A miRNA risk model was built, and its prognostic value was evaluated by R soft packages. Single-sample gene set enrichment analysis was used to assess immune infiltration, and further expression of immune checkpoints was investigated. As a result, miR-421, miR-5001-3p, miR-4326, miR-1915-3p, miR-3177-5p, and miR-4505 were identified to create the risk model. A nomogram consisting of the stage N and risk model predicted overall survival effectively among TNBC patients. Treg and TIL were shown to be strongly linked to the risk model, and the high-risk group had higher levels of four immune checkpoints expression (CD28, CTLA-4, ICOS, and TNFRSF9). A risk model consisting of m7G-related miRNAs was constructed. The findings of the current study could be used as a prognostic biomarker and can provide a novel immunotherapy insight for TNBC patients.

Bone Mesenchymal Stem Cell-Derived Exosome-Enclosed miR-181a Induces CD4+CD25+FOXP3+ Regulatory T Cells via SIRT1/Acetylation-Mediated FOXP3 Stabilization

Bone marrow mesenchymal stem cells (BMSCs) have been identified as a potential therapeutic approach to immune-related diseases. Here, we show that BMSC-derived exosomes promote FOXP3 expression and induce the conversion of CD4⁺ T cells into CD4⁺CD25⁺FOXP3⁺ Treg cells, which is significant for immunosuppressive activity. We found that miR-181a-5p is upregulated in BMSC-derived exosomes and can be transferred to CD4⁺ T cells. In CD4⁺ cells, miR-181a directly targets SIRT1 and suppresses its expression. Moreover, downregulated SIRT1 enhances FOXP3 via protein acetylation. In conclusion, our data demonstrated that BMSC-derived exosomal miR-181a is critical in the maintenance of immune tolerance. Furthermore, our results reveal that BMSC-derived exosomal miR-181a induces the production of CD4⁺CD25⁺FOXP3⁺ Treg cells via SIRT1/acetylation/FOXP3.

The therapeutic capacity of bone marrow MSC-derived extracellular vesicles in Achilles tendon healing is passage dependent and indicated by specific glycans

The therapeutic potential of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) for various diseases and tissue repair is attracting attention. Here, EVs from conditioned medium of human bone marrow MSCs at passage 5 (P5) and 12 (P12) were analyzed using mouse Achilles tendon rupture model and lectin microarray. P5 MSC-EVs accelerated Achilles tendon healing compared with P12 MSC-EVs. Fucose-specific lectin TJA-II was indicated as a glycan marker for therapeutic MSC-EVs. The present study demonstrated that early passaged MSC-EVs promote Achilles tendon healing compared with senescent MSC-EVs. Glycans on MSC-EVs might provide useful tools to establish a quality control and isolation system for therapeutic MSC-EVs in regenerative medicine.

Small Extracellular Vesicle-Derived microRNAs Stratify Prostate Cancer Patients According to Gleason Score, Race and Associate with Survival of African American and Caucasian Men

Simple Summary

Novel biomarkers are needed to guide prognosis and treatment of aggressive forms of prostate cancer (PCa). In this study, small extracellular vesicles (sEVs)-derived microRNAs (miRs) are used to predict aggressive phenotypes and ancestral background of PCa patients. Two cohorts was used to study the diagnostic and prognostic utility of sEV-associated miRs in predicting aggressive forms of PCa in African American (AA) and Caucasian (CA) men. In training cohort, miR profiling was performed and top-ranked sEV-associated miRs were then validated in two independent confirmatory cohorts comprising 150 plasma samples. Results revealed that sEV-associated miR-6068 and miR-1915-3p were enriched in PCa patients compared to healthy subjects. sEV-associated miR-6716-5p and miR-3692-3p distinguished AA from CA men and low from high Gleason score. However, miR-1915-3p was the only studied miR associated with longer recurrence-free survival as independent prognostic marker.

Abstract

The utility of small extracellular vesicles (sEVs)-derived microRNAs (miRs) to segregate prostate cancer (PCa) patients according to tumor aggressiveness and ancestral background has not been fully investigated. Thus, we aimed to determine the diagnostic and prognostic utility of sEV-associated miRs in identifying aggressive PCa in African American (AA) and Caucasian (CA) men. Using a training cohort, miR profiling was performed on sEVs isolated from plasma of PCa patients. Top-ranked sEV-associated miRs were then validated in 150 plasma samples (75 AA and 75 CA) collected from two independent cohorts; NIH (n = 90) and Washington University (n = 60) cohorts. Receiver operating characteristic (ROC) curve, Kaplan–Meier and Cox proportional hazards regression were used to assess these miRs as clinical biomarkers. Among nine top-ranked sEV-associated miRs, miR-6068 and miR-1915-3p were enriched in sEVs collected from PCa patients compared to healthy volunteers. Moreover, miR-6716-5p and miR-3692-3p segregated AA from CA men and low from high Gleason score (GS), respectively. Upregulation of sEV-associated miR-1915-3p, miR-3692-3p and miR-5001-5p was associated with improved survival time, and only miR-1915-3p was associated with longer recurrence-free survival (RFS) as an independent prognostic marker. Taken together, we identified novel sEV-associated miRs that can differentiate PCa patients from normal, AA from CA and high from low GS and predicts RFS.

Cyanidin-3-O-Glucoside Attenuates Lipopolysaccharide-Induced Inflammation in Human Corneal Epithelial Cells by Inducing Let-7b-5p-Mediated HMGA2/PI3K/Akt Pathway

The bacterial keratitis causes viability loss and apoptosis in the corneal epithelial cells (CECs). The cyanidin-3-O-glucoside (C3G) benefits visual system and also possess anti-bacterial and anti-inflammatory potentials. In the current study, the effects of C3G on human CECs (HCECs) against bacterial lipopolysaccharide (LPS)-induced disorders were assessed, and the mechanism driving the protective effect was explored by focusing on let-7b-5p-mediated HMGA2/PI3K/Akt pathway. The HCECs were incubated LPS of P. aeruginosa to induce inflammation and apoptosis, and then treated with C3G. The changes in cell viability, apoptosis, and inflammation were detected. Moreover, the effects of LPS and C3G on let-7b-5p level and HMGA2/PI3K/Akt pathway activity were also assessed. Thereafter, the HCECs were further transfected with let-7b-5p inhibitor to confirm its role in the vision-protective effects of C3G. The interaction between let-7b-5p and HMGA2 was verified with dual luciferase assay. The LPS treatment suppressed viability and induced apoptosis and inflammation in HCECs, which was associated with the down-regulated let-7b-5p level and up-regulated HMGA2/PI3K/Akt pathway activity. The impairments of LPS on HCECs were attenuated by C3G: the compound increased cell viability and inhibited apoptosis and inflammation. The C3G also induced let-7b-5p level and inactivated HMGA2/PI3K/Akt pathway. However, after the inhibition of let-7b-5p, the protective effects of C3G on HCECs against LPS were blocked. The results of dual luciferase assay showed the direct binding let-7b-5p to the promoter of HMGA2 gene. It was inferred that the C3G could ameliorate the LPS-induced disorders in HCECs. The effect depended on the induced level of let-7b-5p, which then inhibited HMGA2/PI3K/Akt pathway.

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.

Epigenetic Regulation in Mesenchymal Stem Cell Aging and Differentiation and Osteoporosis

Mesenchymal stem cells (MSCs) are a reliable source for cell-based regenerative medicine owing to their multipotency and biological functions. However, aging-induced systemic homeostasis disorders in vivo and cell culture passaging in vitro induce a functional decline of MSCs, switching MSCs to a senescent status with impaired self-renewal capacity and biased differentiation tendency. MSC functional decline accounts for the pathogenesis of many diseases and, more importantly, limits the large-scale applications of MSCs in regenerative medicine. Growing evidence implies that epigenetic mechanisms are a critical regulator of the differentiation programs for cell fate and are subject to changes during aging. Thus, we here review epigenetic dysregulations that contribute to MSC aging and osteoporosis. Comprehending detailed epigenetic mechanisms could provide us with a novel horizon for dissecting MSC-related pathogenesis and further optimizing MSC-mediated regenerative therapies.

miR-4651 inhibits cell proliferation of gingival mesenchymal stem cells by inhibiting HMGA2 under nifedipine treatment

Drug-induced gingival overgrowth (DIGO) is recognized as a side effect of nifedipine (NIF); however, the underlying molecular mechanisms remain unknown. In this study, we found that overexpressed miR-4651 inhibits cell proliferation and induces G0/G1-phase arrest in gingival mesenchymal stem cells (GMSCs) with or without NIF treatment. Furthermore, sequential window acquisition of all theoretical mass spectra (SWATH-MS) analysis, bioinformatics analysis, and dual-luciferase report assay results confirmed that high-mobility group AT-hook 2 (HMGA2) is the downstream target gene of miR-4651. Overexpression of HMGA2 enhanced GMSC proliferation and accelerated the cell cycle with or without NIF treatment. The present study demonstrates that miR-4651 inhibits the proliferation of GMSCs and arrests the cell cycle at the G0/G1 phase by upregulating cyclin D and CDK2 while downregulating cyclin E through inhibition of HMGA2 under NIF stimulation. These findings reveal a novel mechanism regulating DIGO progression and suggest the potential of miR-4651 and HMGA2 as therapeutic targets.

Bone marrow-derived humoral factors suppress oxidative phosphorylation, upregulate TSG-6, and improve therapeutic effects on liver injury of mesenchymal stem cells

Mesenchymal stem cells, which have the potential to be used in regenerative medicine, require improvements in quality for patient use. To maintain stemness of cultured bone marrow-derived mesenchymal stem cells, we focused on the bone marrow microenvironment, generated a conditioned medium of whole bone marrow cells (BMC-CM), and assessed its effects on bone marrow-derived mesenchymal stem cells. BMC-CM suppressed morphological deterioration and proliferative decline in cultured bone marrow-derived mesenchymal stem cells, suppressed mitochondrial oxidative phosphorylation activity, a stemness indicator, and upregulated suppressors of oxidative phosphorylation such as hypoxia-inducible factor-1 alpha, Sirtuin 3, 4, and 5. Furthermore, BMC-CM upregulated TNF-stimulated gene 6 and ameliorated the therapeutic effects of cells on liver injury in carbon tetrachloride-administered rats. Since the elimination of 20-220-nm particles attenuated the effects of BMC-CM, we further analyzed exosomal microRNAs produced by whole bone marrow cells. Among the 49 microRNAs observed to be upregulated during the preparation of BMC-CM, several were identified that were associated with suppression of oxidative phosphorylation, upregulation of TNF-stimulated gene 6, and the pathogenesis of liver diseases. Thus, bone marrow-derived humoral factors including exosomal microRNAs may help to improve the therapeutic quality of bone marrow-derived mesenchymal stem cells for liver regenerative therapy.

miR-762 activation confers acquired resistance to gefitinib in non-small cell lung cancer

Background

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) (e.g. gefitinib) currently remain the first-line treatment for patients with advanced non-small-cell lung cancer (NSCLC) with activating EGFR mutation. However, acquired resistance to gefitinib, which occurs frequently through unidentified mechanisms, significantly attenuate therapeutic effectiveness. Previous miRNA microarray analysis reveals that expression levels of a conserved oncomiR miR-762 are significantly upregulated in gefitinib-resistant NSCLC cells. We therefore aim to elucidate the role and underlying mechanisms of miR-762 during the pathogenesis of gefitinib resistance.

Methods

miR-762 expression in gefitinib-resistant NSCLC tissues and cells was evaluated using RT-qPCR. The potential regulation of miR-762 expression by IL-6 was studied using pharmacological and biochemical approaches. Effects of miR-762 manipulation on sensitivity to gefitinib was assessed using MTT, apoptotic ELISA and xenograft model. Finally, the posttranscriptional regulation of active BCR related protein (ABR) by miR-762 was determined using luciferase assay and site-directed mutagenesis.

Results

miR-762 expression was upregulated in gefitinib-resistant NSCLC tissues and cells, and this upregulation predicted a poor post-chemotherapy prognosis in NSCLC patients. miR-762 upregulation, induced by IL-6 signaling, significantly enhanced cell survival and rendered NSCLC cells unresponsiveness to gefitinib-elicited cell death. We finally provided the evidence that the oncogenic effect of miR-762 was mediated mainly through posttranscriptional repression of ABR in gefitinib-resistant NSCLC cells.

Conclusions

Our findings provide a rationale for future efforts testing miR-762 inhibition and ABR restoration co-treatment in patients with recurrent EGFR mutant NSCLC to therapeutically combat the heterogeneity of EGFR-TKIs resistance mechanisms.

MicroRNAs in Ocular Infection

MicroRNAs (miRNAs) are small, non-coding, regulatory RNA molecules and constitute a newly recognized, important layer of gene-expression regulation at post-transcriptional levels. miRNAs quantitatively fine tune the expression of their downstream genes in a cell type- and developmental stage-specific fashion. miRNAs have been proven to play important roles in the normal development and function as well as in the pathogenesis of diseases in all tissues and organ systems. miRNAs have emerged as new therapeutic targets and biomarkers for treatment and diagnosis of various diseases. Although miRNA research in ocular infection remains in its early stages, a handful of pioneering studies have provided insight into the roles of miRNAs in the pathogenesis of parasitic, fungal, bacterial, and viral ocular infections. Here, we review the current status of research in miRNAs in several major ocular infectious diseases. We predict that the field of miRNAs in ocular infection will greatly expand with the discovery of novel miRNA-involved molecular mechanisms that will inform development of new therapies and identify novel diagnostic biomarkers.

miR-1915-3p inhibits Bcl-2 expression in the development of gastric cancer

Many gene expressions changed during the development of gastric cancer, and non-coding RNAs including microRNAs (miRNAs) have been found to regulate cancer progression by participating in the process of tumor cell growth, migration, invasion and apoptosis. Our previous study has identified 29 miRNAs that are highly expressed in gastric cancer stem cells. One of these miRNAs, miR-1915-3p, has shown great potential as a diagnostic and prognostic biomarker for the cancers in liver, colon and thyroid, as well as in immune and kidney diseases. Herein, we found that miR-1915-3p exhibited low expression level in differentiated gastric cancer cell lines and gastric cancer tissues. It was found that the miR-1915-3p inhibited the growth of gastric cancer cells and thus promoted cell apoptosis. We discovered that the expressions of miR-1915-3p were significantly correlated to the lymph node metastasis and overall survival of patients with gastric cancer. Further study showed that there was a negative correlation between miR-1915-3p and Bcl-2 (B cell lymphoma/leukemia-2) expression, suggesting that Bcl-2 was a target gene of miR-1915-3p. Hence, miR-1915-3p possibly contributes to the development and progression of gastric cancer by inhibiting the anti-apoptotic protein Bcl-2. The finding provides a potential therapeutic strategy for gastric cancer.

The miR-3940-5p inhibits cell proliferation of gingival mesenchymal stem cells

OBJECTIVES

Drug-induced gingival overgrowth (DIGO) is a well-recognized side effect of nifedipine (NIF). However, the molecular mechanisms of DIGO are still unknown. Here, we explored the possible role of miR-3940-5p in DIGO using NIF-treated gingival mesenchymal stem cells (GMSCs).

MATERIAL AND METHODS

CFSE and cell cycle assays were used to examine cell proliferation. The alkaline phosphatase (ALP) activity assay, Alizarin Red staining, quantitative calcium analysis, and osteogenesis-related gene expression were used to examine osteo/dentinogenic differentiation.

RESULTS

The CFSE assay showed that NIF enhanced cell proliferation, and the over-expression of miR-3940-5p inhibited the proliferation of GMSCs with or without NIF stimulation. Cell cycle assays revealed that the cell cycle was arrested at the G0/G1 phase. Furthermore, it was found that the over-expression of miR-3940-5p upregulated p15^INK4b , p18^INK4c , p19^INK4d , and Cyclin A and downregulated Cyclin E in GMSCs with or without NIF treatment. In addition, the over-expression of miR-3940-5p enhanced ALP activity and mineralization in vitro and increased the expression of the osteo/dentinogenic differentiation markers DSPP and DMP1 and the key transcription factor DLX5 in GMSCs.

CONCLUSIONS

miR-3940-5p inhibited cell proliferation, enhanced the osteo/dentinogenic differentiation of GMSCs, and might play a role in DIGO as a potent agent in the treatment of nifedipine-induced gingival overgrowth.

Concise Review: TLR Pathway-miRNA Interplay in Mesenchymal Stromal Cells: Regulatory Roles and Therapeutic Directions

Mesenchymal stromal cells (MSCs) deploy Toll-like receptors (TLRs) to respond to exogenous and endogenous signals. Activation of TLR pathways in MSCs alters their inflammatory profile and immunomodulatory effects on cells from both the innate and adaptive immune systems. Micro-RNAs (miRNAs), whose expression is modulated by TLR activation, can regulate inflammatory responses by targeting components of the TLR signaling pathways either in MSCs or in the cells with which they interact. Here, we review how the miRNA-TLR pathway axis can regulate the immunomodulatory functions of MSCs, including their interactions with monocytes/macrophages and natural killer cells, and discuss the therapeutic implications for MSC-based therapies. Stem Cells 2018;36:1655-1662.

Therapeutic potential of microRNAs in osteoporosis function by regulating the biology of cells related to bone homeostasis

MicroRNAs (miRNAs) are novel regulatory factors that play important roles in numerous cellular processes through the posttranscriptional regulation of gene expression. Recently, deregulation of the miRNA-mediated mechanism has emerged as an important pathological factor in osteoporosis. However, a detailed molecular mechanism between miRNAs and osteoporosis is still not available. In this review, the roles of miRNAs in the regulation of cells related to bone homeostasis as well as miRNAs that deregulate in human or animal are discussed. Moreover, the miRNAs that act as clusters in the biology of cells in the bone microenvironment and the difference of some important miRNAs for bone homeostasis between bone and other organs are mentioned. Overall, miRNAs that contribute to the pathogenesis of osteoporosis and their therapeutic potential are considered.

MicroRNA expression in bone marrow-derived human multipotent Stromal cells

Background

Multipotent stromal cells (MSCs) are being studied in the field of regenerative medicine for their multi-lineage differentiation and immunoregulatory capacity. MicroRNAs (miRNAs) are short non-coding RNAs that are responsible for regulating gene expression by targeting transcripts, which can impact MSC functions such as cellular proliferation, differentiation, migration and cell death. miRNAs are expressed in MSCs; however, the impact of miRNAs on cellular functions and donor variability is not well understood. Eight MSC lines were expanded to passages 3, 5 and 7, and their miRNA expression was evaluated using microarray technology.

Results

Statistical analyses of our data revealed that 71 miRNAs out of 939 examined were expressed by this set of MSC lines at all passages and the expression of 11 miRNAs were significantly different between passages 3 and 7, while the expression of 7 miRNAs was significantly different between passages 3 and 5. The expression of these identified miRNAs was evaluated using RT-qPCR for both the first set of MSC lines (n = 6) and a second set of MSC lines (n = 7) expanded from passages 4 to 8. By RT-qPCR only 2 miRNAs, miR-638 and miR-572 were upregulated at passage 7 compared to passage 3 in the first set of MSC lines by 1.71 and 1.54 fold, respectively; and upregulated at passage 8 compared to passage 4 in the second set of MSC lines, 1.35 and 1.59 fold, respectively.

Conclusions

The expression of miR-638 and miR-572 can distinguish MSCs from two different passages of cell culture. These results may be useful in establishing critical quality attributes of MSCs and determining whether changes in these two miRNAs impact cellular functions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3997-7) contains supplementary material, which is available to authorized users.