Making Them Commit: Strategies to Influence Phenotypic Differentiation in Mesenchymal Stem Cells

MIR155HG suppresses the osteogenic differentiation of bone marrow mesenchymal stem cells through regulating miR-155-5p and DKK1 expression

BACKGROUND

Increasing evidence has demonstrated that non-coding RNAs, including the lncRNA MIR155HG, are involved in the pathogenesis of postmenopausal osteoporosis (PMOP). In the current study, we studied MIR155HG function in regulation of osteogenic differentiation and tried to reveal the underlying mechanisms.

METHODS

Forty blood samples taken from 20 PMOP patients (PMOP group) and 20 postmenopausal individuals without osteoporosis (control group) were used to compare the contents of MIR155HG and miR-155-5p via RT-PCR. Alizarin red S staining and ALP staining were used to evaluate the osteogenic differentiation potential of bone marrow mesenchymal stem cells (BMSCs).

RESULTS

Elevated levels of MIR155HG and miR-155-5p were observed in the blood samples of the PMOP group. Upregulation of MIR155HG resulted in decreased expression of OPN, OSX, ALP, RUNX2 and β-catenin but increased DKK1 expression, together with decreased Alizarin red S + and ALP + staining areas. However, downregulation of DKK1 did not obviously change the above indices induced by MIR155HG upregulation. Further experiments revealed that MIR155HG caused an increase in the expression of miR-155-5p, which also serves as an inhibitor of the osteogenic differentiation of BMSCs through binding to β-catenin. Consistent with DKK1 knockdown, downregulation of miR-155-5p only also did not obviously reverse the repressive effect of MIR155HG on osteoblastic differentiation, but downregulation of DKK1 and miR-155-5p synchronously restored the osteogenic differentiation ability of BMSCs suppressed by MIR155HG overexpression.

CONCLUSION

MIR155HG suppressed the osteoblastic differentiation of BMSCs by regulating miR-155-5p and DKK1 expression. Either inhibition of miR-155-5p and DKK1 or direct suppression of MIR155HG may be effective approaches for treating PMOP.

METTL3-mediated m6A modification of circSTAT6 modulates miR-188-3p/Beclin1 axis to promote osteogenic differentiation of mesenchymal stem cells

BACKGROUND

The role of N6-methyladenosine (m6A)-modified circRNAs in disease progression is of great significance. However, the specific impact of m6A modification of circSTAT6 on osteoporosis (OP) is still uncertain.

METHODS

The qRT-PCR was employed to assess the levels of METTL3, circSTAT6, miR-188-3p, and Beclin1. To investigate the interaction between miR-188-3p and circSTAT6 or Beclin, a dual-luciferase reporter assay was performed. To evaluate osteogenic differentiation in bone marrow mesenchymal stem cell (BMSC), western blot analysis was conducted to evaluate the protein expression of osteogenic markers, including ALP, OPN, and Runx2. In addition, alizarin red and alkaline phosphatase (ALP) staining assays were employed to assess osteogenesis.

RESULTS

The findings revealed that the downregulation of circSTAT6 was observed in OP. On the other hand, the overexpression of circSTAT6 was found to enhance the osteogenic differentiation of BMSC. In addition, the involvement of METTL3 in mediating m6A methylation of circSTAT6 was identified, which ultimately promoted osteogenesis. Furthermore, circSTAT6 functioned as an miR-188-3p sponge to regulate the expression of Beclin1. Further study revealed that the osteogenic-enhancing effect caused by circSTAT6 overexpression was counteracted by introducing a miR-188-3p mimic. Similarly, the osteogenic-promoting impact of the miR-188-3p inhibitor was reversed by suppressing Beclin1 expression.

CONCLUSIONS

The present study revealed, for the first time, that METTL3-mediated m6A modification of circSTAT6 regulated the miR-188-3p/Beclin1 axis to promote the osteogenic differentiation of BMSC. These findings offer a potential therapeutic target for the treatment of OP.

MYLK-AS1 improves fracture by targeting miR-146a-5p to regulate cell viability and apoptosis in osteoblasts

BACKGROUND

Delayed fracture healing (DFH) is a significant burden for patients. Therefore, early diagnosis and detection are important for the treatment of DFH. The long non-coding RNA (LncRNA) MYLK-AS1 is abnormally expressed in patients with DFH and has the potential to be used as a diagnostic marker.

METHODS

40 patients with DFH and 87 patients with normal fracture healing were included. The levels of MYLK-AS1, miR-146a-5p and several mRNA markers of osteogenic differentiation were assessed by RT-qPCR. The diagnostic value of MYLK-AS1, miR-146a-5p was assessed using ROC curves. Cell proliferation ability was assessed by CCK-8, and apoptosis rate was detected by flow cytometry. DLR, RIP and RNA pull down assays demonstrated the targeting relationship between MYLK-AS1 and miR-146a-5p.

RESULTS

MYLK-AS1 levels were significantly lower and miR-146a-5p levels were significantly up-regulated in DFH compared to normal healing patients. MYLK-AS1 was found to target miR-146a-5p, and the levels were negatively correlated with each other. MYLK-AS1 with miR-146a-5p is of high value for the diagnosis of DFH. High expression of MYLK-AS1 could inhibit miR-146a-5p levels, support cell proliferation, reduce apoptosis, and increase the levels of osteogenesis-specific matrix proteins and osteogenesis-related regulatory factors.

CONCLUSION

MYLK-AS1 has potential as a diagnostic marker for DFH. By increasing the expression level of MYLK-AS1 in cells can reduce the level of miR-146a-5p, increase the activity of osteoblasts and reduce their apoptosis rate, thus affecting the process of fracture healing.

Icariin promotes osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by activating PI3K-AKT-UTX/EZH2 signaling in steroid-induced femoral head osteonecrosis

BACKGROUND

Differentiation of bone marrow mesenchymal stem cells (BMSCs) is pivotal in the pathogenesis of steroid-induced femoral head osteonecrosis. Icariin, an active ingredient in Epimedii herba, has the potential to regulate osteogenic differentiation of BMSCs. Nevertheless, the related mechanism is still unclear. The study aimed to explore whether icariin can affect osteogenic differentiation by activating PI3K/AKT signaling to alter UTX and EZH2 expression and thus regulating osteogenesis-related genes in BMSCs.

METHODS

BMSCs were collected from Sprague Dawley rats and identified by measuring the positive ratios of cell markers using flow cytometry. Cells were treated with 1 μmol/L dexamethasone (DEX) for 24 h with or without 0.1-10 μM of icariin treatment. Cell counting Kit-8 (CCK-8) assays and flow cytometry analyses were performed to measure cell viability and apoptosis. Western blotting was conducted for measurement of apoptotic markers, factors involved in the PI3K/AKT-UTX/EZH2 pathway, osteogenic markers, and adipogenesis-related factors. Alizarin red S staining and Oil-red O staining were performed to measure the effect of DEX, icariin, UTX overexpression, or EZH2 knockdown on osteogenic and adipogenic differentiation of BMSCs.

RESULTS

Icariin ameliorated DEX-induced rat BMSC injury. Icariin activated the PI3K/AKT signaling, thereby upregulating UTX and phosphorylated EZH2 levels while inhibiting EZH2 and H3K27me3 expression. Additionally, icariin promoted osteogenic differentiation and inhibited adipogenic differentiation of BMSCs. Importantly, overexpressing UTX or silencing EZH2 exerted similar effects on BMSC differentiation as icariin did.

CONCLUSIONS

Icariin promotes osteogenic differentiation of DEX-treated BMSCs by activating PI3K/AKT signaling to upregulate UTX and inhibit EZH2, finally inducing H3K27me3 depletion.

LINC00968 accelerates osteogenic differentiation of bone marrow mesenchymal stem cells via the miR-17-5p/STAT3 axis

BACKGROUND

BMSCs with robust osteogenic differentiation capacity can participate in the repair of osteoporotic (OP) bone. Long non-coding RNAs (LncRNAs) serve as crucial regulators of osteogenic differentiation. This study aims to investigate the clinical implications of LINC00968 in OP and elucidate its molecular mechanisms.

METHODS

Patients with OP and controls without OP were enrolled. RT-qPCR was utilized the quantify the levels of LINC00968, miR-17-5p, STAT3, and osteogenic differentiation markers. ROC curve was conducted to evaluate the diagnostic significance. Osteogenic differentiation medium (OM) induced hBMSCs. Flow cytometry was used to examine apoptosis. DLR and RIP assay were performed to validate target binding.

RESULTS

LINC00968 was notably decreased in the serum and bone tissue of patients with OP, whereas it was markedly elevated during osteogenic differentiation of hBMSCs. LINC00968 has 78.65% sensitivity and 71.95% specificity in identifying OP patients from controls. Silencing of LINC00968 sharply diminished ALP activity and osteogenic differentiation markers levels while promoting apoptosis in hBMSCs under OM induction. However, this reduction was notably reversed by the administration of a miR-17-5p inhibitor. Molecularly, miR-17-5p directly targets LINC00968 and STAT3.

CONCLUSIONS

Our results indicate that LINC00968 downregulation is a diagnostic biomarker for OP, facilitating osteogenic differentiation and inhibiting apoptosis via miR-17-5p/STAT3 axis, suggesting a new therapeutic target for OP progression.

Activation of osteoblast ferroptosis by risperidone accelerates bone loss in mice models of schizophrenia

BACKGROUND

Ferroptosis is an iron-dependent regulatory cell death, which plays an essential role in bone loss. This study investigated whether the mechanism of risperidone (RIS)-induced bone loss is related to ferroptosis.

METHODS

The schizophrenia mice were induced by administering MK-801. Subsequently, RIS were injected, or ferroptosis inhibitor Ferrostatin-1 (Fer-1) co-injected for 8 weeks. Bone loss of schizophrenia mice were assessed using microCT, H&E staining, ALP staining, ARS staining and WB, respectively. Ferroptosis of schizophrenia mice were detected by Iron Colorimetric Assay Kit and WB, respectively. In addition, ALP staining, ARS staining, and WB were performed to reveal the role of RIS in osteogenic differentiation of MC3T3-E1 and BMSCs cells.

RESULTS

RIS treatment facilitates bone loss in schizophrenia mice and inhibit osteogenic differentiation of MC3T3-E1 and BMSCs cells. Moreover, up-regulated ferroptosis was found in vivo and in vitro after RIS treatment. Interesting, the bone loss and inhibition of osteogenic differentiation induced by RIS in schizophrenia mice were reversed by ferroptosis inhibitor Fer-1.

CONCLUSION

Ferroptosis induced by RIS aggravates the bone loss of schizophrenia mice via inhibiting osteogenic differentiation.

B-doped nano-hydroxyapatite facilitates proliferation and differentiation of osteoblasts

PURPOSE

We aimed to explore the mechanism by which Boron-doped nano-hydroxyapatite (B-nHAp) facilitates the proliferation and differentiation of osteoblasts through controlled release of B.

METHODS

B-nHAp characterization was accomplished by means of X-ray diffraction, scanning electron microscopy, inductively coupled plasma mass spectrometry, and transmission electron microscopy. Human bone marrow mesenchymal stem cells (hBMSCs) were subjected to flow cytometry, alizarin red S staining, and cell counting kit-8 assay for proliferation and differentiation determination. Western blotting for protein expression detection together with real-time quantitative polymerase chain reaction for mRNA expression measurement were carried out on those related to hBMSC proliferation and differentiation. Immunofluorescence staining was conducted to determine the activity of the Wnt/β-catenin signaling pathway.

RESULTS

B-nHAp particles had structured configuration and uniform size, and a typical nHAp crystal structure. The B content in B-nHAp was in line with expectation. hBMSCs displayed stemness. B-nHAp significantly facilitated the proliferation of hBMSCs, and significantly more mineralized nodules formed in the B-nHAp group. B-nHAp significantly upregulated the expressions of marker molecules related to hBMSC proliferation and differentiation. B-nHAp boosted the activity of the Wnt/β-catenin signaling pathway.

CONCLUSION

B-nHAp modulates the Wnt/β-catenin signaling pathway to significantly enhance the proliferative and differential abilities of osteoblasts, potentially as an efficient material for bone repair.

17β-estradiol promotes osteogenic differentiation of BMSCs by regulating mitophagy through ARC

The study aims to elucidate the mechanism through which 17β-estradiol facilitates osteogenic differentiation in bone marrow mesenchymal stem cells (BMSCs). In our study, lentiviral transfection was employed to establish apoptosis repressor with caspase recruitment domain (ARC) knockdown or overexpression in BMSCs. The impact of 17β-estradiol on ARC expression was assessed using western blot, RT-PCR and immunofluorescence. Techniques such as ALP staining, ALP activity assay, western blot, RT-PCR and immunofluorescence staining were utilized to examine the influence of ARC expression levels on the osteogenic differentiation of BMSCs and the osteoclastic differentiation of Raw264.7 cell lines. Mitophagy flux levels in BMSCs were detected using the mitophagy detection kit. RNA sequencing and bioinformatics analyses were conducted to explore potential mechanisms of ARC regulation in BMSCs osteogenic differentiation. To sum up, 17β-estradiol can modulate bone homeostasis by adjusting ARC expression. ARC stimulates mitophagy in BMSCs via MAPK/Akt pathway, identifying ARC as a promising therapeutic target for postmenopausal osteoporosis (PMOP) treatment.

The composition of cell-based therapies obtained from point-of-care devices/systems which mechanically dissociate lipoaspirate: a scoping review of the literature

PURPOSE

Cell-based therapies using lipoaspirate are gaining popularity in orthopaedics due to their hypothesised regenerative potential. Several 'point-of-care' lipoaspirate-processing devices/systems have become available to isolate cells for therapeutic use, with published evidence reporting their clinical relevance. However, few studies have analysed the composition of their 'minimally-manipulated' cellular products in parallel, information that is vital to understand the mechanisms by which these therapies may be efficacious. This scoping review aimed to identify devices/systems using mechanical-only processing of lipoaspirate, the constituents of their cell-based therapies and where available, clinical outcomes.

METHODS

PRISMA extension for scoping reviews guidelines were followed. MEDLINE, Embase and PubMed databases were systematically searched to identify relevant articles until 21st April 2022. Information relating to cellular composition and clinical outcomes for devices/systems was extracted. Further information was also obtained by individually searching the devices/systems in the PubMed database, Google search engine and contacting manufacturers.

RESULTS

2895 studies were screened and a total of 15 articles (11 = Level 5 evidence) fulfilled the inclusion criteria. 13 unique devices/systems were identified from included studies. All the studies reported cell concentration (cell number regardless of phenotype per millilitre of lipoaspirate) for their devices/systems (range 0.005-21 × 106). Ten reported cell viability (the measure of live cells- range 60-98%), 11 performed immuno-phenotypic analysis of the cell-subtypes and four investigated clinical outcomes of their cellular products. Only two studies reported all four of these parameters.

CONCLUSION

When focussing on cell concentration, cell viability and MSC immuno-phenotypic analysis alone, the most effective manual devices/systems were ones using filtration and cutting/mincing. However, it was unclear whether high performance in these categories would translate to improved clinical outcomes. Due to the lack of standardisation and heterogeneity of the data, it was also not possible to draw any reliable conclusions and determine the role of these devices/systems in clinical practice at present.

LEVEL OF EVIDENCE

Level V Therapeutic.

TGFβ1-transfected tendon stem cells promote tendon fibrosis

Background

In aged people, tendon injuries frequently occur during sporting and daily activities. In clinical practice, typical physiotherapeutic, pharmacotherapeutic, and surgical techniques do not result in the full recovery of injured tendons, which may lead to chronic degenerative disease.

Methods

We first isolated tendon stem cells (TSCs) from rats and transfected them with the TGFβ1 gene, resulting in TGFβ1-TSCs. The proliferation of TSCs was detected using the Cell Counting Kit 8, and TSCs were identified by immunofluorescence analysis and differentiation capacity analysis. Aggrecan, COL2A1, alpha smooth muscle actin (α-SMA), and p-Smad2 expression levels were detected using western blotting and quantitative reverse transcription polymerase chain reaction. Additionally, a tendon injury model was generated to explore the effect of TGFβ1 on the repair of the tendon by TSCs.

Results

Compared with fibrinogen treatment, TSC + fibrinogen or TGFβ1-TSC + fibrinogen treatment significantly promoted the fibrosis of injured tendons, as evidenced by histological analyses, with TGFβ1-TSC + fibrinogen having a greater effect than TSC + fibrinogen. In TGFβ1-TSCs, increased expression levels of aggrecan and COL2A1 indicated that TGFβ1 signaling induced chondrogenic differentiation. Meanwhile, the increased collagen and α-SMA protein levels indicated that TGFβ1 promoted fibrogenesis. Additionally, TGFβ1 stimulated the production of phosphorylated Smad2 in TSCs, which suggested that the chondrogenic and fibrogenic differentiation of TSCs, as well as tissue regeneration, may be associated with the TGFβ1/Smad2 pathway.

Conclusion

TGFβ1-TSC therapy may be a candidate for effective tendon fibrosis.

Small interfering RNAs in the management of human rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) has unclear pathogenesis, but the molecules that feed its inflammatory state are known. Small interfering RNAs (siRNAs) are useful to identify molecular targets and evaluate the efficacy of specific drugs, and can themselves be used for therapeutic purposes.

SOURCES OF DATA

A systematic search of different databases to March 2022 was performed to define the role of siRNAs in RA therapy. Twenty suitable studies were identified.

AREAS OF AGREEMENT

Small interfering RNAs can be useful in the study of inflammatory processes in RA, and identify possible therapeutic targets and drug therapies.

AREAS OF CONTROVERSY

Many genes and cytokines participate in the inflammatory process of RA and can be regulated with siRNA. However, it is difficult to determine whether the responses to siRNAs and other drugs studied in human cells in vitro are similar to the responses in vivo.

GROWING POINTS

Inflammatory processes can be affected by the gene dysregulation of siRNAs on inflammatory cytokines.

AREAS TIMELY FOR DEVELOPING RESEARCH

To date, it is not possible to determine whether the pharmacological response of siRNAs on cells in vitro would be similar to what takes place in vivo for the diseases studied so far.

Adipose-derived mesenchymal stem cells with hypoxic preconditioning improve tenogenic differentiation

Background

Adipose-derived mesenchymal stem cells (ADSCs), as seed cells for tendon tissue engineering, are promising for tendon repair and regeneration. But for ADSCs, diverse oxygen tensions have different stimulatory effects. To explore this issue, we investigated the tenogenic differentiation capability of ADSCs under hypoxia condition (5% O₂) and the possible signaling pathways correspondingly. The effects of different oxygen tensions on proliferation, migration, and tenogenic differentiation potential of ADSCs were investigated.

Methods

P4 ADSCs were divided into a hypoxic group and a normoxic group. The hypoxic group was incubated under a reduced O₂ pressure (5% O₂, 5% CO₂, balanced N₂). The normoxic group was cultured in 21% O₂. Two groups were compared: HIF-1α inhibitor (2-MeOE2) in normoxic culturing conditions and hypoxic culturing conditions. Hypoxia-inducible factor-1α (HIF-1α) and VEGF were measured using RT-qPCR. Specific HIF-1α inhibitor 2-methoxyestradiol (2-MeOE2) was applied to investigate whether HIF-1α involved in ADSCs tenogenesis under hypoxia.

Results

Hypoxia significantly reduced proliferation and migration of ADSCs. Continuous treatment of ADSCs at 5% O₂ resulted in a remarkable decrease in HIF-1α expression in comparison with 20% O₂. Additionally, ADSCs of hypoxia preconditioning exhibited higher mRNA expression levels of the related key tenogenic makers and VEGF than normoxia via RT-qPCR measurement (p ˂ 0.05). Furthermore, the effects of hypoxia on tenogenic differentiation of ADSCs were inhibited by 2-MeOE2. Hypoxia can also stimulate VEGF production in ADSCs.

Conclusions

Our findings demonstrate that hypoxia preconditioning attenuates the proliferation and migration ability of ADSCs, but has positive impact on tenogenic differentiation through HIF-1α signaling pathway.

Immunomodulatory extracellular vesicles: an alternative to cell therapy for COVID-19

Introduction: SARS-CoV-2 induces a cytokine storm and can cause inflammation, fibrosis and apoptosis in the lungs, leading to acute respiratory distress syndrome (ARDS). ARDS is the leading cause of mortality and morbidity the associated to COVID-19, and the cytokine storm is a prominent etiological factor. Mesenchymal stem cell-derived extracellular vesicles are an alternative therapy for the management of inflammatory and autoimmune conditions due to their immunosuppressive properties. The immunomodulatory and tissue regeneration capabilities of extracellular vesicles may support their application as a prospective therapy for COVID-19.Areas Covered: We explored the clinical evidence on extracellular vesicles as antiviral agents and in mitigating ARDS, and their therapeutic potential in COVID-19.Expert Opinion: Clinical trials using extracellular vesicles are registered against COVID-19 associated complications, with some evidence of safety and efficacy. Extracellular vesicles present an alternative potential for cell therapy for COVID-19 management, but further preclinical and clinical investigations are needed.

Differences in the biological properties of mesenchymal stromal cells from traumatic temporomandibular joint fibrous and bony ankylosis: a comparative study

The aim of this study was to compare the functional characteristics of mesenchymal stromal cells (MSCs) from a sheep model of traumatic temporomandibular joint (TMJ) fibrous and bony ankylosis. A sheep model of bilateral TMJ trauma-induced fibrous ankylosis on one side and bony ankylosis on the contralateral side was used. MSCs from fibrous ankylosed callus (FA-MSCs) or bony ankylosed callus (BA-MSCs) at weeks 1, 2, 4, and 8 after surgery were isolated and cultured. MSCs derived from the bone marrow of the mandibular condyle (BM-MSCs) were used as controls. The MSCs from the different sources were characterized morphologically, phenotypically, and functionally. Adherence and trilineage differentiation potential were presented in the ovine MSCs. These cell populations highly positively expressed MSC-associated specific markers, namely CD29, CD44, and CD166, but lacked CD31 and CD45 expressions. The BA-MSCs had higher clonogenic and proliferative potentials than the FA-MSCs. The BA-MSCs also showed higher osteogenic and chondrogenic potentials, but lower adipogenic capacity than the FA-MSCs. In addition, the BA-MSCs demonstrated higher chondrogenic, but lower osteogenic capacity than the BM-MSCs. Our study suggests that inhibition of the osteogenic and chondrogenic differentiations of MSCs might be a promising strategy for preventing bony ankylosis in the future.

Basic Research on Tendon Repair: Strategies, Evaluation, and Development

Tendon is a fibro-elastic structure that links muscle and bone. Tendon injury can be divided into two types, chronic and acute. Each type of injury or degeneration can cause substantial pain and the loss of tendon function. The natural healing process of tendon injury is complex. According to the anatomical position of tendon tissue, the clinical results are different. The wound healing process includes three overlapping stages: wound healing, proliferation and tissue remodeling. Besides, the healing tendon also faces a high re-tear rate. Faced with the above difficulties, management of tendon injuries remains a clinical problem and needs to be solved urgently. In recent years, there are many new directions and advances in tendon healing. This review introduces tendon injury and sums up the development of tendon healing in recent years, including gene therapy, stem cell therapy, Platelet-rich plasma (PRP) therapy, growth factor and drug therapy and tissue engineering. Although most of these therapies have not yet developed to mature clinical application stage, with the repeated verification by researchers and continuous optimization of curative effect, that day will not be too far away.

Salidroside promoted osteogenic differentiation of adipose-derived stromal cells through Wnt/β-catenin signaling pathway

BACKGROUND

Bone disease causes short-term or long-term physical pain and disability. It is necessary to explore new drug for bone-related disease. This study aimed to explore the role and mechanism of Salidroside in promoting osteogenic differentiation of adipose-derived stromal cells (ADSCs).

METHODS

ADSCs were isolated and treated with different dose of Salidroside. Cell count kit-8 (CCK-8) assay was performed to assess the cell viability of ADSCs. Then, ALP and ARS staining were conducted to assess the early and late osteogenic capacity of ADSCs, respectively. Then, differentially expressed genes were obtained by R software. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the differentially expressed genes were further analyzed. The expression of OCN, COL1A1, RUNX2, WNT3A, and β-catenin were measured by real-time PCR and Western blot analysis. Last, β-catenin was silenced by small interfering RNA.

RESULTS

Salidroside significantly increased the ADSCs viability at a dose-response manner. Moreover, Salidroside enhanced osteogenic capacity of ADSCs, which are identified by enhanced ALP activity and calcium deposition. A total of 543 differentially expressed genes were identified between normal and Salidroside-treated ADSCs. Among these differentially expressed genes, 345 genes were upregulated and 198 genes were downregulated. Differentially expressed genes enriched in the Wnt/β-catenin signaling pathway. Western blot assay indicated that Salidroside enhanced the WNT3A and β-catenin expression. Silencing β-catenin partially reversed the promotion effects of Salidroside. PCR and Western blot results further confirmed these results.

CONCLUSION

Salidroside promoted osteogenic differentiation of ADSCs through Wnt/β-catenin signaling pathway.

Amnion-Derived Teno-Inductive Secretomes: A Novel Approach to Foster Tendon Differentiation and Regeneration in an Ovine Model

Regenerative medicine has greatly progressed, but tendon regeneration mechanisms and robust in vitro tendon differentiation protocols remain to be elucidated. Recently, tendon explant co-culture (CO) has been proposed as an in vitro model to recapitulate the microenvironment driving tendon development and regeneration. Here, we explored standardized protocols for production and storage of bioactive tendon-derived secretomes with an evaluation of their teno-inductive effects on ovine amniotic epithelial cells (AECs). Teno-inductive soluble factors were released in culture-conditioned media (CM) only in response to active communication between tendon explants and stem cells (CMCO). Unsuccessful tenogenic differentiation in AECs was noted when exposed to CM collected from tendon explants (CMFT) only, whereas CMCO upregulated SCXB, COL I and TNMD transcripts, in AECs, alongside stimulation of the development of mature 3D tendon-like structures enriched in TNMD and COL I extracellular matrix proteins. Furthermore, although the tenogenic effect on AECs was partially inhibited by freezing CMCO, this effect could be recovered by application of an in vivo-like physiological oxygen (2% O2) environment during AECs tenogenesis. Therefore, CMCO can be considered as a waste tissue product with the potential to be used for the development of regenerative bio-inspired devices to innovate tissue engineering application to tendon differentiation and healing.

Cell-based therapy in soft tissue sports injuries of the knee: a systematic review

INTRODUCTION

An ever-increasing number of clinics are offering purportedly 'regenerative' stem-cell treatments, although cell-based therapies may not primarily act as stem cells and have shown the ability to regenerate end-target tissues in some clinical studies only. We aim to systematically review the evidence for their use in soft-tissue sports injuries of the knee.

AREAS COVERED

A search for articles pertaining to the use of preparations of, or containing, mesenchymal stem cells (MSCs) in human subjects in sports knee injuries yielded 14 relevant results for inclusion after screening: 7 used cultured MSCs, 5 bone marrow concentrate (BMC), and the remaining 2 evaluated stromal vascular fraction (SVF) and tenocyte-like-cells. Most studies were level 3 or lower (n = 9).

EXPERT OPINION

There is insufficient high-quality evidence for the use of cell-based therapies that demonstrates either ligamentous or tendinous healing, meniscal volume restoration, or post-traumatic osteoarthritis amelioration/regression. Methods of cell harvesting, preparation, and application are highly heterogenous. Efforts should be directed toward standardization of protocols and their reporting, starting with more basic scientific investigations of MSCs and their niche, as well as rigorous, large clinical RCTs adhering to the reporting principles set out by recent expert consensus.

BM-MSCs differentiated to chondrocytes for treatment of full-thickness cartilage defect of the knee

Background

Full-thickness articular cartilage injury of the knee is a major cause of disability. The aim of this study is to assess the outcome of patients treated with differentiated to chondrocytes bone marrow mesenchymal stem cells (BM-MSCs) cultured on a collagen type I/III (Chondro-Gide®) scaffold. The secondary aim was to confirm the absence of adverse events.

Methods

Fifteen patients (19 knees) with symptomatic full-thickness cartilage defects of the knee were enrolled. Bone marrow was harvested from the iliac crest, BM-MSCs were prepared, and expanded cells were grown in a standard medium or in a standard culture medium containing TGF-β. BM-MSCs differentiated to chondrocytes were seeded in a porcine collagen type I/III scaffold (Chondro-Gide®) and cultured in TGF-β containing media. After 4 weeks, the membrane was sutured on the cartilage defect. All patients underwent plain radiographs (antero-posterior, lateral, and axial view of the patella) and MRI of the affected knee. The Oxford knee score, the Lyhsolm scale, and the VAS score were administered to all patients. At final follow-up a MRI for the study of articular cartilage was undertaken.

Results

The mean size of the cartilage lesions was 20 × 17 mm (range, 15 × 10 mm–30 × 30 mm). At final follow-up, the median Oxford knee score and Lyhsolm scale scores significantly improved from 29 (range 12–39; SD 7.39) to 45 (range 24–48; SD 5.6) and from 55.5 (range 25–81; SD 17.7) to 94.5 (58–100; SD 10.8), respectively. Pain, according to the VAS score, significantly improved. Sixty percent of patients reported their satisfaction as excellent, 20% as good, 14% as fair, and 1 patient as poor.

Conclusion

The treatment of full-thickness chondral injuries of the knee with differentiated to chondrocytes BM-MSCs and Chondro-Gide® scaffold showed encouraging outcomes. Further studies involving more patients, and with longer follow-up, are required to evaluate the effectiveness of the treatment and the long-term results.

Electrospun thymosin Beta-4 loaded PLGA/PLA nanofiber/ microfiber hybrid yarns for tendon tissue engineering application

Microfiber yarns (MY) have been widely employed to construct tendon tissue grafts. However, suboptimal ultrastructure and inappropriate environments for cell interactions limit their clinical application. Herein, we designed a modified electrospinning device to coat poly(lactic-co-glycolic acid) PLGA nanofibers onto polylactic acid (PLA) MY to generate PLGA/PLA hybrid yarns (HY), which had a well-aligned nanofibrous structure, resembling the ultrastructure of native tendon tissues and showed enhanced failure load compared to PLA MY. PLGA/PLA HY significantly improved the growth, proliferation, and tendon-specific gene expressions of human adipose derived mesenchymal stem cells (HADMSC) compared to PLA MY. Moreover, thymosin beta-4 (Tβ4) loaded PLGA/PLA HY presented a sustained drug release manner for 28 days and showed an additive effect on promoting HADMSC migration, proliferation, and tenogenic differentiation. Collectively, the combination of Tβ4 with the nano-topography of PLGA/PLA HY might be an efficient strategy to promote tenogenesis of adult stem cells for tendon tissue engineering.