miR-27a promotes osteogenic differentiation in glucocorticoid-treated human bone marrow mesenchymal stem cells by targeting PI3K

Differences in microRNA within plasma extracellular vesicles at various time points during early pregnancy in sheep revealed by high-throughput sequencing data

Exosome microRNAs are vital for gene transcription and expression, influencing target genes. They may play direct and indirect roles in pregnancy across animal models and humans. The objective of this research was to comprehensively explore the expression profiles of plasma exosomal miRNAs during the early pregnancy stage in sheep. This study specifically delved into the differences in the expression of plasma exosomal miRNAs between Chinese Merino and Suffolk sheep. The primary focus was on clearly elucidating the changes in plasma exosomal miRNAs, pinpointing potential biomarkers that might exert an impact on early pregnancy, and thoroughly exploring their biological functions as well as the possible underlying molecular mechanisms. Chinese Merino and Suffolk sheep were divided into two groups of 20 for artificial insemination. Blood samples were collected at various pregnancy stages (day 0, day 14, and day 30), Ultrasound diagnosis was carried out five weeks following artificial insemination. Three pregnant sheep from each group were selected for isolating extracellular vesicle-derived miRNAs from plasma. High-throughput sequencing identified differentially expressed miRNAs, and their target genes were analyzed using bioinformatics methods. In plasma exosomal samples derived from all sheep of both breeds at various time points during the early pregnancy stage, a cumulative total of 80 known miRNAs and 182 novel miRNAs were successfully identified. Compared to day 0 gestation controls, both sheep breeds showed differential expression of six known miRNAs: four were up- regulated and two down- regulated. Pathway analysis linked these miRNAs to biological processes such as ECM receptor interactions, growth hormone synthesis, carbohydrate digestion, adrenergic signaling in cardiomyocytes, and MAPK signaling regulation. Notably, Oar-mir-27a differed between the two groups at various time points. In summary, this research meticulously carried out a profiling analysis of the expression of plasma exosomal miRNAs in Chinese Merino and Suffolk sheep. Through this analysis, several exosomal miRNAs were identified, which display distinct abundance levels during the early pregnancy period. These findings strongly imply that these miRNAs have the potential to serve as biomarkers for precisely assessing the reproductive status of sheep.

Circulating biomarkers associated with walking performance in elderly subjects: exploring miRNAs, metabolic and inflammatory biomarkers

Aging phenotype is characterized by musculoskeletal impairment that leads to diminished mobility and physical function. This study investigated whether circulating miRNAs and metabolic and inflammatory biomarkers may reflect the walking performance of the elderly. Elderly hospitalized for an acute condition and recruited from the ReportAge Biobank were grouped, based on their walking performance, in active subjects (n = 23, age: 83.0 ± 4.3), able to walk ≥ 1 km and who performed more than 1 h activity, and inactive subjects (n = 23, age: 85.0 ± 6.0), able to walk < 100 m and who performed < 1 h activity in the 3 days prior hospitalization. Plasma levels of 754 miRNAs were evaluated using OpenArray® platform, and miRNAs whose level was ± 2.5 fold (p < 0.05) were validated by qPCR. Target prediction for validated miRNAs was performed on MirWalk 3.0, Gene Ontology and pathway enrichment on Panther 19.0. Cytokines and metabolites associated with bone, muscle, and inflammation were evaluated from plasma samples using Luminex and ELISA. Among the 7 miRNAs found differentially expressed in active compared to inactive elderly after the initial screening, 4 miRNAs were validated: hsa-let7g-5p, hsa-miR-27a-3p, hsa-miR-361-5p, hsa-miR-574-3p, all upregulated in the active group. Gene Ontology and pathway enrichment analysis revealed the identified miRNAs potentially involved in muscle and bone metabolism during aging. Among cytokines, gp130 and IL-10 significantly differed between the two groups. This study suggests the potential association of specific circulating biomarkers with walking performance in elderly and their potential involvement in the molecular mechanism underlying age-associated musculoskeletal impairment.

Profiling the extracellular vesicles of two human placenta-derived mesenchymal stromal cell populations

Increasing evidence shows extracellular vesicles (EVs) are primarily responsible for the beneficial effects of cell-based therapies. EVs derived from mesenchymal stromal cells (MSCs) show promise as a source of EVs for cell-free therapies. The human placental fetal-maternal interface is a rich and abundant source of MSCs from which EVs can be isolated. This study focusses on chorionic MSCs (CMSC) located on the fetal aspect of the interface and decidual MSCs (DMSC) on the maternal aspect. This study used Ligand-based Exosome Affinity Purification (LEAP) chromatography to isolate EVs from well-characterized placental hTERT-transduced CMSC29 and DMSC23 cell lines, which retain many important stem cell-like properties of primary CMSC and DMSC, respectively. After initial biophysical characterization of the EVs isolated from each cell line, the biological activities and the protein, lipid and small RNA contents of CMSC29-EVs and DMSC23-EVs were compared and assessed. LEAP-purified EVs from both sources were validated at the biophysical level by Spectradyne, Cryo-Transmission Electron Microscopy (Cryo-TEM), and Western blot analysis. EVs from each type were labelled with the live cell stain PKH26 and their in vitro uptake and internalization by human dermal fibroblast cells was assessed, as well as their phosphorylation of the protein kinase B/AKT (AKT) pathway. The protein and lipid contents were analyzed by mass spectrometry and the nucleic acid content by RNA sequencing (RNA-seq). Lastly, the biological activities of the EVs were evaluated in a BioMAP® Diversity PLUS® screen system across a panel of 12 human primary cell-based systems and in vitro cell proliferation. EVs isolated from both DMSC23 and CMSC29 significantly increased proliferation of fibroblasts and showed phosphorylation of the AKT pathway. Protein mass spectrometry analysis identified a large number of proteins including cell surface receptors, cytokines, chemokines, matrix molecules and enzymes in both EV types. Lipidomic analysis identified species including phosphatidylcholine, triacylglycerides and diacylglycerides in both DMSC23 and CMSC29-derived EVs. There were some significant differences in identified microRNAs (miRNAs) between the two EV types. The top differentially expressed miRNAs between the two EV types show pathways association with matrix interaction, transcriptional regulation, proliferation, cellular protein modification processes, and vasculogenesis. Differences were also detected between DMSC23- and CMSC29-EVs in the biological activity they displayed in the BioMAP® Diversity PLUS® screen.

miR-181a/MSC-Loaded Nano-Hydroxyapatite/Collagen Accelerated Bone Defect Repair in Rats by Targeting Ferroptosis Pathway

Background: The reparative regeneration of jawbone defects poses a significant challenge within the field of dentistry. Despite being the gold standard, autogenous bone materials are not without drawbacks, including a heightened risk of postoperative infections. Consequently, the development of innovative materials that can surpass the osteogenic capabilities of autologous bone has emerged as a pivotal area of research. Methods: Mesenchymal stem cells (MSCs), known for their multilineage differentiation potential, were isolated from human umbilical cords and transfected with miR-181a. The osteogenic differentiation of miR-181a/MSC was investigated. Then, physicochemical properties of miR-181a/MSC-loaded nano-hydroxyapatite (nHAC) scaffolds were characterized, and their efficacy and underlying mechanism in rat calvarial defect repair were explored. Results: miR-181a overexpression in MSCs significantly promoted osteogenic differentiation, as evidenced by increased alkaline phosphatase activity and expression of osteogenic markers. The miR-181a/MSC-loaded nHAC scaffolds exhibited favorable bioactivity and accelerated bone tissue repair and collagen secretion in vivo. Mechanistic studies reveal that miR-181a directly targeted the TP53/SLC7A11 pathway, inhibiting ferroptosis and enhancing the osteogenic capacity of MSCs. Conclusions: The study demonstrates that miR-181a/MSC-loaded nHAC scaffolds significantly enhance the repair of bone defects by promoting osteogenic differentiation and inhibiting ferroptosis. These findings provide novel insights into the molecular mechanisms regulating MSC osteogenesis and offer a promising therapeutic strategy for bone defect repair.

YTHDF2-Mediated m6A methylation inhibition by miR27a as a protective mechanism against hormonal osteonecrosis in BMSCs

BACKGROUND

With the increasing incidence of steroid-induced necrosis of the femoral head (SNFH), numerous scholars have investigated its pathogenesis. Current evidence suggests that the imbalance between lipogenesis and osteoblast differentiation in bone marrow mesenchymal stem cells (BMSCs) is a key pathological feature of SNFH. MicroRNAs (miRNAs) have strong gene regulatory effects and can influence the direction of cell differentiation. N6-methyladenosine (m6A) is a prevalent epigenetic modification involved in diverse pathophysiological processes. However, knowledge of how miRNAs regulate m6A-related factors that affect BMSC differentiation is limited.

OBJECTIVE

We aimed to investigate the role of miR27a in regulating the expression of YTHDF2 in BMSCs.

METHODS

We compared miR27a, YTHDF2, and total m6A mRNA levels in SNFH-affected and control BMSCs. CCK-8 and TUNEL assays were used to assess BMSC proliferation and apoptosis. Western blotting and qRT‒PCR were used to measure the expression of osteogenic (ALP, RUNX2, and OCN) and lipogenic (PPARγ and C/EBPα) markers. Alizarin Red and Oil Red O staining were used to quantify osteogenic and lipogenic differentiation, respectively. miR27a was knocked down or overexpressed to evaluate its impact on BMSC differentiation and its relationship with YTHDF2. Bioinformatics analyses identified YTHDF2 as a differentially expressed gene in SNFH (ROC analysis) and revealed potential signaling pathways through GSEA. The effects of YTHDF2 silencing on the lipogenic and osteogenic functions of BMSCs were assessed.

RESULTS

miR27a downregulation and YTHDF2 upregulation were observed in the SNFH BMSCs. miR27a knockdown/overexpression modulated YTHDF2 expression, impacting BMSC differentiation. miR27a silencing decreased m6A methylation and promoted osteogenic differentiation, while YTHDF2 silencing exerted similar effects. GSEA suggested potential signaling pathways associated with YTHDF2 in SNFH.

CONCLUSION

miR27a regulates BMSC differentiation through YTHDF2, affecting m6A methylation and promoting osteogenesis. This finding suggests a potential therapeutic target for SNFH.

miR-27a Targeting PIK3R3 Regulates the Proliferation and Apoptosis of Sheep Hair Follicle Stem Cells

Micro RNAs are regulatory factors in tissue development, organ formation, cell growth, apoptosis and other biological processes. In particular, several miRNAs are related to the development of hair follicles. Here, we investigated the effect of the targeting of PIK3R3 by miR-27a on the AKT/MTOR pathway and on the proliferation and apoptosis of hair follicle stem cells (HFSCs) in sheep. Knockdown of the expression of PIK3R3 was found to significantly inhibit the proliferation and promote the apoptosis of HFSCs. Similarly, a miR-27a mimic significantly inhibited the proliferation and promoted the apoptosis of HFSCs. The miR-27a mimic was also shown to significantly inhibit the expression of PIK3R3, AKT, and MTOR and the phosphorylation of AKT and MTOR, while a miR-27a inhibitor increased the expression of these genes. The presence of an miR-27a binding site in the 3' UTR of PIK3R3 was identified by a bioinformatics analysis, and the interaction was verified with a dual-luciferase reporter assay. The expression of PIK3R3 mRNA and protein was negatively correlated with the presence of miR-27a, which suggests that this interaction may be involved in the biological impacts on proliferation and apoptosis. Thus, this study demonstrates that miR-27a plays a potential role in the proliferation and apoptosis of sheep hair follicle stem cells by targeting PIK3R3, which can be used to design new methods to improve sheep wool.

The potential effect of BMSCs with miR-27a in improving steroid-induced osteonecrosis of the femoral head

Steroid induced osteonecrosis of the femoral head (ONFH) frequently leads to femoral head collapse and subsequent hip arthritis. This study aimed to investigate the potential therapeutic mechanism of miR-27a on steroid-induced ONFH. Levels of IL-6, TNF-α, miR-27a, Runx2, PPAR-γ and ApoA5 were first examined in bone marrow tissues from steroid-induced ONFH and controls. Subsequently, we overexpressed or knocked down miR-27a in bone marrow mesenchymal stem cells (BMSCs) and detected cell proliferation, osteogenic differentiation, adipogenic differentiation. In addition, miR-27a mimics and BMSCs were injected into the established steroid-induced ONFH rats, and the osteoprotective effects of both were evaluated. Dual luciferase reporter was used to test the targeting effect of miR-27a-3p and PPARG. miR-27a and Runx2 were lowly expressed in steroid-induced ONFH, PPAR-γ and ApoA5 were highly expressed. Overexpression of miR-27a in BMSCs promoted cell proliferation and osteogenic differentiation, inhibited adipogenic differentiation. Furthermore, increasing miR-27a and BMSCs obviously reduced bone loss in steroid induced ONFH rats. The expressions of Runx2 in BMSCs and steroid-induced ONFH rats was significantly up-regulated, while IL-6, TNF-α, PPAR-γ and ApoA5 were down-regulated with miR-27a overexpression. Additionally, PPARG was the target of miR-27a-3p. The results of the present study reveal a role for miR-27a in promoting osteogenesis and may have a synergistic effect with BMSCs.

Exosomal miR-150 derived from BMSCs inhibits TNF-α-mediated osteoblast apoptosis in osteonecrosis of the femoral head by GREM1/NF-κB signaling

Aim: The purpose of this study was to investigate the functions of exosomal miR-150 derived from bone marrow mesenchymal stem cells in osteonecrosis of the femoral head (ONFH). Materials & methods: Cell viability and apoptosis were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry. Alizarin red staining was performed to detect calcium deposits. A rat model was established to assess the effects of exosomal miR-150 on ONFH in vivo. Results: Exosomes or exosomal miR-150 derived from bone marrow mesenchymal stem cells inhibited TNF-α-induced osteoblast apoptosis and promoted osteogenic differentiation and autophagy. Exosomal miR-150 suppressed apoptosis and induced autophagy in TNF-α-treated osteoblasts by regulating the GREM1/NF-κB axis. Exosomal miR-150 also improved the pathological features of ONFH in vivo. Conclusion: Exosomal miR-150 alleviates ONFH by mediating the GREM1/NF-κB axis. This study provides a potential therapeutic strategy for ONFH.

The Emerging Role of Non-Coding RNAs in Osteogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells

Autologous bone marrow-derived mesenchymal stem cells (BMSCs) are more easily available and frequently used for bone regeneration in clinics. Osteogenic differentiation of BMSCs involves complex regulatory networks affecting bone formation phenomena. Non-coding RNAs (ncRNAs) refer to RNAs that do not encode proteins, mainly including microRNAs, long non-coding RNAs, circular RNAs, piwi-interacting RNAs, transfer RNA-derived small RNAs, etc. Recent in vitro and in vivo studies had revealed the regulatory role of ncRNAs in osteogenic differentiation of BMSCs. NcRNAs had both stimulatory and inhibitory effects on osteogenic differentiation of BMSCs. During the physiological condition, osteo-stimulatory ncRNAs are upregulated and osteo-inhibitory ncRNAs are downregulated. The opposite effects might occur during bone degenerative disease conditions. Intracellular ncRNAs and ncRNAs from neighboring cells delivered via exosomes participate in the regulatory process of osteogenic differentiation of BMSCs. In this review, we summarize the recent advances in the regulatory role of ncRNAs on osteogenic differentiation of BMSCs during physiological and pathological conditions. We also discuss the prospects of the application of modulation of ncRNAs function in BMSCs to promote bone tissue regeneration in clinics.

Human Umbilical Cord Mesenchymal Stem Cells Improve the Necrosis and Osteocyte Apoptosis in Glucocorticoid-Induced Osteonecrosis of the Femoral Head Model through Reducing the Macrophage Polarization

Background and Objectives

Apoptosis is an outstanding determinant of glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH). Human umbilical cord mesenchymal stem cells (hUC-MSCs) have been demonstrated to be associated with apoptosis in diseases models. However, the role of hUC-MSCs in GC-induced ONFH via regulating apoptosis still needs further study.

Methods and Results

In the present study, a GC-induced ONFH model was built in vivo through a consecutive injection with lipopolysaccharide (LPS) and methylprednisolone. The necrosis and apoptosis of the femoral head was evaluated by histological and Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) assay. The level of collagen and TRAP positive cells were determined by Masson and TRAP staining, respectively. M1 macrophage polarization was assessed using immunofluorescence assay. The level of proinflammatory cytokines including tumor necrosis factor (TNF)‐α, Interleukin (IL)‐1β and IL-6 of femoral head was determined by enzyme-linked immunosorbent assay (ELISA) kits. The protein expression of AKT, mTOR, p-AKT and p-mTOR was detected using western blot assay. The results showed that hUC-MSCs treatment prominently promoted the GC-induced the decrease of the collagen level and the increase of TRAP positive cells. Besides, hUC-MSCs treatment decreased necrosis and apoptosis, macrophage polarization, the level of TNF‐α, IL‐1β and IL-6, the protein expression of p-AKT and p-mTOR, and the radio of p-AKT to AKT and p-mTOR to mTOR of femoral head in vivo.

Conclusions

Therefore, the present study revealed that hUC-MSCs improved the necrosis and osteocyte apoptosis in GC-induced ONFH model through reducing the macrophage polarization, which was associated with the inhibition of AKT/mTOR signaling pathway.