Articular chondrocyte-derived extracellular vesicles promote cartilage differentiation of human umbilical cord mesenchymal stem cells by activation of autophagy

Regulation of mesenchymal stem cell differentiation by autophagy

Autophagy, a process that isolates intracellular components and fuses them with lysosomes for degradation, plays an important cytoprotective role by eliminating harmful intracellular substances and maintaining cellular homeostasis. Mesenchymal stem cells (MSCs) are multipotent progenitor cells with the capacity for self-renewal that can give rise to a subset of tissues and therefore have potential in regenerative medicine. However, a variety of variables influence the biological activity of MSCs following their proliferation and transplantation in vitro. The regulation of autophagy in MSCs represents a possible mechanism that influences MSC differentiation properties under the right microenvironment, affecting their regenerative and therapeutic potential. However, a deeper understanding of exactly how autophagy is mobilized to function as well as clarifying the mechanisms by which autophagy promotes MSCs differentiation is still needed. Here, we review the current literature on the complex link between MSCs differentiation and autophagy induced by various extracellular or intracellular stimuli and the molecular targets that influence MSCs lineage determination, which may highlight the potential regulation of autophagy on MSCs' therapeutic capacity, and provide a broader perspective on the clinical application of MSCs in the treatment of a wide range of diseases.

Extracellular Vesicles Generated by Mesenchymal Stem Cells in Stirred Suspension Bioreactors Promote Angiogenesis in Human-Brain-Derived Endothelial Cells

Interrupted blood flow in the brain due to ischemic injuries such as ischemic stroke or traumatic brain injury results in irreversible brain damage, leading to cognitive impairment associated with inflammation, disruption of the blood-brain barrier (BBB), and cell death. Since the BBB only allows entry to a small class of drugs, many drugs used to treat ischemia in other tissues have failed in brain-related disorders. The administration of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) has shown promise in improving the functional recovery of the brain following cerebral ischemia by inducing blood vessel formation. To facilitate such a treatment approach, it is necessary to develop bioprocesses that can produce therapeutically relevant MSC-EVs in a reproducible and scalable manner. This study evaluated the feasibility of using stirred suspension bioreactors (SSBs) to scale-up the serum-free production of pro-angiogenic MSC-EVs under clinically relevant physioxic conditions. It was found that MSCs grown in SSBs generated EVs that stimulated angiogenesis in cerebral microvascular endothelial cells, supporting the use of SSBs to produce MSC-EVs for application in cerebral ischemia. These properties were impaired at higher cell confluency, outlining the importance of considering the time of harvest when developing bioprocesses to manufacture EV populations.

Toll-like receptor activation regulates the paracrine effect of adipose-derived mesenchymal stem cells on reversing osteoarthritic phenotype of chondrocytes

BACKGROUND

The therapeutic efficacy of intra-articular mesenchymal stem cells (MSCs) injection for patients with osteoarthritis (OA) currently exhibits inconsistency, and the underlying mechanism remains elusive. It has been postulated that the immunomodulatory properties and paracrine activity of MSCs might be influenced by the inflammatory micro-environment within osteoarthritic joints, potentially contributing to this observed inconsistency.

METHODS

Adipose-derived MSCs (ADSCs) were isolated from SD rats and pre-treated with Toll-like receptor 3 (TLR3) agonist Poly I:C or Toll-like receptor 4 (TLR4) agonist LPS. The pre-treated ADSCs were then co-cultured with IL-1β-induced osteoarthritic chondrocytes using a Transwell system to analyze the paracrine effect of ADSCs on reversing the osteoarthritic phenotype of chondrocytes.

RESULTS

RT-PCR and Western blot analysis revealed that Poly I:C and LPS pre-treatments up-regulated the expression of IL-10 and IL-6 in ADSCs, respectively. Furthermore, only Poly I:C-preconditioned ADSCs significantly promoted proliferation while inhibiting apoptosis in IL-1β-treated chondrocytes. Additionally, Poly I:C-preconditioned ADSCs downregulated MMP13 expression while upregulating aggrecan and collagen II expression levels in IL-1β-treated chondrocytes.

CONCLUSIONS

TLR3 activation polarizes ADSCs into an immunomodulatory phenotype distinct from TLR4 activation, exerting differential effects on reversing the osteoarthritic phenotype of chondrocytes; thus indicating that MSCs' paracrine effect regulated by TLRs signaling impacts the efficacy of intra-articular MSCs injection.

Extracellular vesicles are key players in mesenchymal stem cells' dual potential to regenerate and modulate the immune system

MSCs are used for treatment of inflammatory conditions or for regenerative purposes. MSCs are complete cells and allogenic transplantation is in principle possible, but mostly autologous use is preferred. In recent years, it was discovered that cells secrete extracellular vesicles. These are active budded off vesicles that carry a cargo. The cargo can be miRNA, protein, lipids etc. The extracellular vesicles can be transported through the body and fuse with target cells. Thereby, they influence the phenotype and modulate the disease. The extracellular vesicles have, like the MSCs, immunomodulatory or regenerative capacities. This review will focus on those features of extracellular vesicles and discuss their dual role. Besides the immunomodulation, the regeneration will concentrate on bone, cartilage, tendon, vessels and nerves. Current clinical trials with extracellular vesicles for immunomodulation and regeneration that started in the last five years are highlighted as well. In summary, extracellular vesicles have a great potential as disease modulating entity and treatment. Their dual characteristics need to be taken into account and often are both important for having the best effect.

Extracellular Vesicles and Hydrogels: An Innovative Approach to Tissue Regeneration

Extracellular vesicles have emerged as promising tools in regenerative medicine due to their inherent ability to facilitate intercellular communication and modulate cellular functions. These nanosized vesicles transport bioactive molecules, such as proteins, lipids, and nucleic acids, which can affect the behavior of recipient cells and promote tissue regeneration. However, the therapeutic application of these vesicles is frequently constrained by their rapid clearance from the body and inability to maintain a sustained presence at the injury site. In order to overcome these obstacles, hydrogels have been used as extracellular vesicle delivery vehicles, providing a localized and controlled release system that improves their therapeutic efficacy. This Review will examine the role of extracellular vesicle-loaded hydrogels in tissue regeneration, discussing potential applications, current challenges, and future directions. We will investigate the origins, composition, and characterization techniques of extracellular vesicles, focusing on recent advances in exosome profiling and the role of machine learning in this field. In addition, we will investigate the properties of hydrogels that make them ideal extracellular vesicle carriers. Recent studies utilizing this combination for tissue regeneration will be highlighted, providing a comprehensive overview of the current research landscape and potential future directions.

Extracellular Vesicles Derived from Auricular Chondrocytes Facilitate Cartilage Differentiation of Adipose-Derived Mesenchymal Stem Cells

PURPOSE

Adipose-derived mesenchymal stem cell (ADSC)-based therapies have been utilized for cartilage regeneration because of their multi-lineage differentiation ability. However, commonly used cartilage inducers such as the transforming growth factor beta-3 (TGF-β3) may be prone to cartilage dedifferentiation and hypertrophy. The directional differentiation of elastic cartilage is limited nowadays. Extracellular vesicles (EVs) have been reported to influence the specific differentiation of mesenchymal stem cells (MSCs) by reflecting the composition of the parental cells. However, the role of auricular chondrogenic-derived EVs (AC-EVs) in elastic chondrogenic differentiation of ADSCs has not yet been reported.

RESULTS

AC-EVs isolated from the external ears of swine exhibited a positive effect on cell proliferation and migration. Furthermore, AC-EVs efficiently promoted chondrogenic differentiation of ADSCs in pellet culture, as shown by the elevated levels of COL2A1, ACAN, and SOX-9 expression. Moreover, there was a significantly higher expression of elastin and a lower expression of the fibrotic marker COL1A1 in comparison with that achieved with TGF-β3. The staining results demonstrated that AC-EVs promoted the deposition of cartilage-specific matrix, which is in good concordance with the real-time polymerase chain reaction (RT-PCR) results.

CONCLUSIONS

Auricular chondrogenic-derived EVs are a crucial component in elastic chondrogenic differentiation and other biological behaviors of ADSCs, which may be a useful ingredient for cartilage tissue engineering and external ear reconstruction.

NO LEVEL ASSIGNED

This journal requires that authors 42 assign a level of evidence to each submission to which 43 Evidence-Based Medicine rankings are applicable. This 44 excludes Review Articles, Book Reviews, and manuscripts 45 that concern Basic Science, Animal Studies, Cadaver 46 Studies, and Experimental Studies. For a full description of 47 these Evidence-Based Medicine ratings, please refer to the 48 Table oôf Contents or the online Instructions to Authors 49 www.springer.com/00266 .

The Dual Role of Small Extracellular Vesicles in Joint Osteoarthritis: Their Global and Non-Coding Regulatory RNA Molecule-Based Pathogenic and Therapeutic Effects

OA is the most common joint disease that affects approximately 7% of the global population. Current treatment methods mainly relieve its symptoms with limited repairing effect on joint destructions, which ultimately contributes to the high morbidity rate of OA. Stem cell treatment is a potential regenerative medical therapy for joint repair in OA, but the uncertainty in differentiation direction and immunogenicity limits its clinical usage. Small extracellular vesicles (sEVs), the by-products secreted by stem cells, show similar efficacy levels but have safer regenerative repair effect without potential adverse outcomes, and have recently drawn attention from the broader research community. A series of research works and reviews have been performed in the last decade, providing references for the application of various exogenous therapeutic sEVs for treating OA. However, the clinical potential of target intervention involving endogenous pathogenic sEVs in the treatment of OA is still under-explored and under-discussed. In this review, and for the first time, we emphasize the dual role of sEVs in OA and explain the effects of sEVs on various joint tissues from both the pathogenic and therapeutic aspects. Our aim is to provide a reference for future research in the field.

A comprehensive analysis of biomarkers associated with synovitis and chondrocyte apoptosis in osteoarthritis

Introduction

Osteoarthritis (OA) is a chronic disease with high morbidity and disability rates whose molecular mechanism remains unclear. This study sought to identify OA markers associated with synovitis and cartilage apoptosis by bioinformatics analysis.

Methods

A total of five gene-expression profiles were selected from the Gene Expression Omnibus database. We combined the GEO with the GeneCards database and performed Gene Ontology and Kyoto Encyclopedia of Genes and Genome analyses; then, the least absolute shrinkage and selection operator (LASSO) algorithm was used to identify the characteristic genes, and a predictive risk score was established. We used the uniform manifold approximation and projection (UMAP) method to identify subtypes of OA patients, while the CytoHubba algorithm and GOSemSim R package were used to screen out hub genes. Next, an immunological assessment was performed using single-sample gene set enrichment analysis and CIBERSORTx.

Results

A total of 56OA-related differential genes were selected, and 10 characteristic genes were identified by the LASSO algorithm. OA samples were classified into cluster 1 and cluster 2 subtypes byUMAP, and the clustering results showed that the characteristic genes were significantly different between these groups. MYOC, CYP4B1, P2RY14, ADIPOQ, PLIN1, MFAP5, and LYVE1 were highly expressed in cluster 2, and ANKHLRC15, CEMIP, GPR88, CSN1S1, TAC1, and SPP1 were highly expressed in cluster 1. Protein-protein interaction network analysis showed that MMP9, COL1A, and IGF1 were high nodes, and the differential genes affected the IL-17 pathway and tumor necrosis factor pathway. The GOSemSim R package showed that ADIPOQ, COL1A, and SPP1 are closely related to the function of 31 hub genes. In addition, it was determined that mmp9 and Fos interact with multiple transcription factors, and the ssGSEA and CIBERSORTx algorithms revealed significant differences in immune infiltration between the two OA subtypes. Finally, a qPCR experiment was performed to explore the important genes in rat cartilage and synovium tissues; the qPCR results showed that COL1A and IL-17A were both highly expressed in synovitis tissues and cartilage tissues of OA rats, which is consistent with the predicted results.

Discussion

In the future, common therapeutic targets might be found forsimultaneous remissions of both phenotypes of OA.

Co-aggregation of MSC/chondrocyte in a dynamic 3D culture elevates the therapeutic effect of secreted extracellular vesicles on osteoarthritis in a rat model

Extracellular vesicles (EVs) have therapeutic effects on osteoarthritis (OA). Some recent strategies could elevate EV's therapeutic properties including cell aggregation, co-culture, and 3D culture. It seems that a combination of these strategies could augment EV production and therapeutic potential. The current study aims to evaluate the quantity of EV yield and the therapeutic effect of EVs harvested from rabbit mesenchymal stem cells (MSCs) aggregates, chondrocyte aggregates, and their co-aggregates in a dynamic 3D culture in a rat osteoarthritis model. MSC and chondrocytes were aggregated and co-aggregated by spinner flasks, and their conditioned medium was collected. EVs were isolated by size exclusion chromatography and characterized in terms of size, morphology and surface markers. The chondrogenic potential of the MSC-ag, Cho-ag and Co-ag EVs on MSC micromass differentiation in chondrogenic media were assessed by qRT-PCR, histological and immunohistochemical analysis. 50 μg of MSC-ag-EVs, Cho-ag-EVs and Co-ag-EVs was injected intra-articularly per knee of OA models established by monoiodoacetate in rats. After 8 weeks follow up, the knee joints were harvested and analyzed by radiographic, histological and immunohistochemical features. MSC/chondrocyte co-aggregation in comparison to MSC or chondrocyte aggregation could increase EV yield during dynamic 3D culture by spinner flasks. Although MSC-ag-, Cho-ag- and Co-ag-derived EVs could induce chondrogenesis similar to transforming growth factor-beta during in vitro study, Co-ag-EV could more effectively prevent OA progression than MSC-ag- and Cho-ag-EVs. Our study demonstrated that EVs harvested from the co-aggregation of MSCs and chondrocytes could be considered as a new therapeutic potential for OA treatment.

The Critical Role of Hypoxia in the Re-Differentiation of Human Articular Chondrocytes

The preservation of the chondrogenic phenotype and hypoxia-related physiological microenvironment are major challenges in the 2D culture of primary human chondrocytes. To address this problem, we develop a 3D culture system generating scaffold-free spheroids from human chondrocytes. Our results highlight the chondrogenic potential of cultured human articular chondrocytes in a 3D system combined with hypoxia independently of the cartilage source. After 14 days of culture, we developed spheroids with homogenous diameter and shape from hyaline cartilage donors. Spheroids generated in hypoxia showed a significantly increased glycosaminoglycans synthesis and up-regulated the expression of SOX9, ACAN, COL2A1, COMP, and SNAI1 compared to those obtained under normoxic conditions. Therefore, we conclude that spheroids developed under hypoxic conditions modulate the expression of chondrogenesis-related genes and native tissue features better than 2D cultures. Thus, this scaffold-free 3D culture system represents a novel in vitro model that can be used for cartilage biology research.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles Carrying MicroRNA-181c-5p Promote BMP2-Induced Repair of Cartilage Injury through Inhibition of SMAD7 Expression

The therapy role of mesenchymal stem cell- (MSC-) derived extracellular vesicles (EVs) in cartilage regeneration has been well studied. Herein, we tried to analyze the role of human umbilical cord MSC- (hUCMSC-) EVs carrying microRNA- (miR-) 181c-5p in repair of cartilage injury. After successful isolation of hUCMSCs, the multidirectional differentiation abilities were analyzed. Then, the EVs were isolated and identified. After coculture of PKH26-labled EVs with bone marrow MSCs (BMSCs), the biological behaviors of which were detected. The relationship between the predicted early posttraumatic osteoarthritis-associated miRNA, miR-181c-5p, and SMAD7 was verified. Gain- and loss-of functions were performed for investing the role of miR-181c-5p and SMAD7 in BMP-induced chondrogenesis in vitro and in vivo. hUCMSC-EVs could be internalized by BMSCs and promote the proliferative, migratory, and chondrogenic differentiation potentials of BMSCs. Additionally, miR-181c-5p could target and inhibit SMAD7 expression to promote the bone morphogenic protein 2- (BMP2-) induced proliferative, migratory, and chondrogenic differentiation potentials of BMSCs. Also, overexpression of SMAD7 inhibited the repairing effect of BMP2, and overexpression of BMP2 and miR-181c-5p further promoted the repair of cartilage injury in vivo. Our present study highlighted the repairing effect of hUCMSC-EVs carrying miR-181c-5p on cartilage injury.

An Emerging Frontier in Intercellular Communication: Extracellular Vesicles in Regeneration

Regeneration requires cellular proliferation, differentiation, and other processes that are regulated by secreted cues originating from cells in the local environment. Recent studies suggest that signaling by extracellular vesicles (EVs), another mode of paracrine communication, may also play a significant role in coordinating cellular behaviors during regeneration. EVs are nanoparticles composed of a lipid bilayer enclosing proteins, nucleic acids, lipids, and other metabolites, and are secreted by most cell types. Upon EV uptake by target cells, EV cargo can influence diverse cellular behaviors during regeneration, including cell survival, immune responses, extracellular matrix remodeling, proliferation, migration, and differentiation. In this review, we briefly introduce the history of EV research and EV biogenesis. Then, we review current understanding of how EVs regulate cellular behaviors during regeneration derived from numerous studies of stem cell-derived EVs in mammalian injury models. Finally, we discuss the potential of other established and emerging research organisms to expand our mechanistic knowledge of basic EV biology, how injury modulates EV biogenesis, cellular sources of EVs in vivo, and the roles of EVs in organisms with greater regenerative capacity.

Analysis and identification of m6A RNA methylation regulators in metastatic osteosarcoma

Osteosarcoma (OS) is characterized by rapid growth and early metastasis. However, its mechanism remains unclear. N6-methyladenosine (m6A) modification and its regulatory factors play essential roles in most cancers, including OS. In this study, we screened out 21 m6A modifiers using the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database, followed by the identification of the critical m6A methylation modifiers. The results revealed that the expression levels of three m6A methylation regulators, namely RBM15, METTL3, and LRPPRC, were associated with the low survival rate of patients with OS. We further studied the independent prognostic factors by performing univariate and multivariate Cox analyses and found that metastasis was an independent prognostic factor for patients with OS. Furthermore, we found for the first time that RBM15 was specific for metastatic OS rather than non-metastatic OS. Moreover, the significant overexpression of RBM15 was validated in metastatic OS cell lines and in actual human clinical specimens. We also revealed that RBM15 promoted the invasion, migration, and metastasis of OS cells through loss-functional and gain-functional experiments and an animal metastatic model. In conclusion, RBM15 has a high correlation with OS metastasis formation and the decreased survival rate of patients with OS, and this may serve as a useful biomarker for predicting metastasis and prognosis of patients with OS.

Extracellular vesicles: a promising cell-free therapy for cartilage repair

Few effective therapies for cartilage repair have been found as cartilage has a low regenerative capacity. Extracellular vesicles (EVs), including exosomes, are produced by cells and contain bioactive components such as nucleic acids, proteins, lipids and other metabolites that have potential for treating cartilage injuries. Challenges like the difficulty in standardizing targeted therapy have prevented EVs from being used frequently as a treatment option. In this review we present current studies, mechanisms and delivery strategies of EVs. Additionally, we describe the challenges and future directions of EVs as therapeutic agents for cartilage repair.

Repairing cartilage damage is challenging due to the tissue’s low regenerative capacity. Extracellular vesicles (EVs) contain bioactive components that may be able to treat cartilage injuries. However, EV-based therapy is not widely used. This review summarizes the current state of knowledge regarding the use of EVs for cartilage repair, including the mechanisms, delivery strategies, challenges and future directions.

Anti-inflammatory and immunomodulatory effects of the extracellular vesicles derived from human umbilical cord mesenchymal stem cells on osteoarthritis via M2 macrophages

Osteoarthritis (OA) is a degenerative illness that greatly impacts the life quality of patients. Currently, the therapeutic approaches for OA are very limited in clinical. The extracellular vesicles (EVs) derived from different mesenchymal stem cells displayed a prominent therapeutic effect on OA. But most EVs have limited resources and the risks of host rejection, immunological response, and etc. Human umbilical cord mesenchymal stem cells (hUCMSCs) hold the advantages of easy availability, minimal immune rejection, and excellent immunomodulatory effects, although hUCMSCs-EVs have seldom been applied in OA. Herein, we investigated the potential immunomodulatory and anti-inflammatory effects of hUCMSCs-EVs on the treatment of OA. In our results, the treatment of hUCMSCs-EVs promoted the polarization of M2-type macrophages and the expression of anti-inflammation-related cytokines (IL-10). Notably, the supernate of M2 macrophages induced by hUCMSCs-EVs inhibited the level of inflammation-associated factors in OA chondrocytes caused by IL-1β. Further, injection of hUCMSCs-EVs in the articular lumen ameliorated progression of OA and exerted chondroprotective potential based on the OA joint model created by the surgical transection of the anterior cruciate ligament (ACLT). In addition, we found five highly enriched miRNAs in hUCMSCs-EVs, including has-miR-122-5p, has-miR-148a-3p, has-miR-486-5p, has-miR-let-7a-5p, and has-miR-100-5p by High-throughput sequencing of miRNAs, with targeted genes mainly enriched in the PI3K-Akt signaling pathway. Furthermore, we also detected the protein abundance of hUCMSCs-EVs using liquidation chromatography with tandem quadrupole mass spectrometry (LC–MS/MS) analysis. Thus, our study indicates that hUCMSCs-EVs can alleviate cartilage degradation during the OA progression, mechanically may through delivering key proteins and modulating the PI3K-Akt signaling pathway mediated by miRNAs to promote polarization of M2 macrophage, exhibiting potent immunomodulatory potential. The current findings suggest that hUCMSCs-EVs might serve as a new reagent for the therapy of OA.

Graphical Abstract

Harnessing Tissue-derived Extracellular Vesicles for Osteoarthritis Theranostics

Osteoarthritis (OA) is a prevalent chronic whole-joint disease characterized by low-grade systemic inflammation, degeneration of joint-related tissues such as articular cartilage, and alteration of bone structures that can eventually lead to disability. Emerging evidence has indicated that synovium or articular cartilage-secreted extracellular vesicles (EVs) contribute to OA pathogenesis and physiology, including transporting and enhancing the production of inflammatory mediators and cartilage degrading proteinases. Bioactive components of EVs are known to play a role in OA include microRNA, long non-coding RNA, and proteins. Thus, OA tissues-derived EVs can be used in combination with advanced nanomaterial-based biosensors for the diagnostic assessment of OA progression. Alternatively, mesenchymal stem cell- or platelet-rich plasma-derived EVs (MSC-EVs or PRP-EVs) have high therapeutic value for treating OA, such as suppressing the inflammatory immune microenvironment, which is often enriched by pro-inflammatory immune cells and cytokines that reduce chondrocytes apoptosis. Moreover, those EVs can be modified or incorporated into biomaterials for enhanced targeting and prolonged retention to treat OA effectively. In this review, we explore recently reported OA-related pathological biomarkers from OA joint tissue-derived EVs and discuss the possibility of current biosensors for detecting EVs and EV-related OA biomarkers. We summarize the applications of MSC-EVs and PRP-EVs and discuss their limitations for cartilage regeneration and alleviating OA symptoms. Additionally, we identify advanced therapeutic strategies, including engineered EVs and applying biomaterials to increase the efficacy of EV-based OA therapies. Finally, we provide our perspective on the future of EV-related diagnosis and therapeutic potential for OA treatment.

OUP accepted manuscript

Mesenchymal progenitor cells (MPCs) have shown promise initiating articular cartilage repair, with benefits largely attributed to the trophic factors they secrete. These factors can be found in the conditioned medium (CM) collected from cell cultures, and it is believed that extracellular vesicles (EVs) within this CM are at least partially responsible for MPC therapeutic efficacy. This study aimed to examine the functionality of the EV fraction of CM compared to whole CM obtained from human adipose-derived MPCs in an in vivo murine cartilage defect model. Mice treated with whole CM or the EV fraction demonstrated an enhanced cartilage repair score and type II collagen deposition at the injury site compared to saline controls. We then developed a scalable bioprocess using stirred suspension bioreactors (SSBs) to generate clinically relevant quantities of MPC-EVs. Whereas static monolayer culture systems are simple to use and readily accessible, SSBs offer increased scalability and a more homogenous environment due to constant mixing. This study evaluated the biochemical and functional properties of MPCs and their EV fractions generated in static culture versus SSBs. Functionality was assessed using in vitro MPC chondrogenesis as an outcome measure. SSBs supported increased MPC expression of cartilage-specific genes, and EV fractions derived from both static and SSB culture systems upregulated type II collagen production by MPCs. These results suggest that SSBs are an effective platform for the generation of MPC-derived EVs with the potential to induce cartilage repair.

Nampt promotes fibroblast extracellular matrix degradation in stress urinary incontinence by inhibiting autophagy

Stress urinary incontinence (SUI) is defined as involuntary urinary leakage happening in exertion. Nicotinamide phosphoribosyltransferase (Nampt) is seldom researched in the pathogenesis of SUI. Accordingly, the current study set out to elucidate the role of Nampt in SUI progression. Firstly, we determined Nampt expression patterns in SUI patients and rat models. In addition, fibroblasts were obtained from the anterior vaginal wall tissues of non-SUI patients and subjected to treatment with different concentrations of interleukin-1β (IL-1β), followed by quantification of Nampt expressions in fibroblasts. Subsequently, an appropriate concentration of IL-1β was selected to treat anterior vaginal wall fibroblasts. Nampt was further silenced in IL-1β-treated fibroblasts to assess the role of Nampt in autophagy and extracellular matrix (ECM) degradation. Lastly, functional rescue assays were carried out to inhibit autophagy and evaluate the role of autophagy in the mechanism of Nampt modulating IL-1β-treated fibroblast ECM degradation. It was found that Nampt was highly-expressed in SUI patients and rat models and IL-1β-treated fibroblasts. On the other hand, Nampt silencing was found to suppress ECM degradation and promote SUI fibroblast autophagy. Additionally, inhibition of autophagy attenuated the inhibitory effects of Nampt silencing on SUI fibroblast ECM degradation. Collectively, our findings revealed that Nampt was over-expressed in SUI, whereas Nampt silencing enhanced SUI fibroblast autophagy, and thereby inhibited ECM degradation.

Extracellular Vesicles in Musculoskeletal Regeneration: Modulating the Therapy of the Future

Tissue regeneration is a hot topic in health sciences, particularly because effective therapies promoting the healing of several cell types are lacking, specifically those of the musculoskeletal system. Mesenchymal Stem/Stromal Cells (MSCs) have been identified as crucial players in bone homeostasis, and are considered a promising therapy for diseases such as osteoarthritis (OA) and Rheumatoid Arthritis (RA). However, some known drawbacks limit their use, particularly ethical issues and immunological rejections. Thus, MSCs byproducts, namely Extracellular Vesicles (EVs), are emerging as potential solutions to overcome some of the issues of the original cells. EVs can be modulated by either cellular preconditioning or vesicle engineering, and thus represent a plastic tool to be implemented in regenerative medicine. Further, the use of biomaterials is important to improve EV delivery and indirectly to modulate their content and secretion. This review aims to connect the dots among MSCs, EVs, and biomaterials, in the context of musculoskeletal diseases.

Higher Chondrogenic Potential of Extracellular Vesicles Derived from Mesenchymal Stem Cells Compared to Chondrocytes-EVs In Vitro

The inability of cartilage to self-repair necessitates an effective therapeutic approach to restore damaged tissues. Extracellular vesicles (EVs) are attractive options because of their roles in cellular communication and tissue repair where they regulate the cellular processes of proliferation, differentiation, and recruitment. However, it is a challenge to determine the relevant cell sources for isolation of EVs with high chondrogenic potential. The current study aims to evaluate the chondrogenic potential of EVs derived from chondrocytes (Cho-EV) and mesenchymal stem cells (MSC-EV). The EVs were separately isolated from conditioned media of both rabbit bone marrow MSCs and chondrocyte cultures. The isolated vesicles were assessed in terms of size, morphology, and surface marker expression. The chondrogenic potential of MSCs in the presence of different concentrations of EVs (50, 100, and 150 μg/ml) was evaluated during 21 days, and chondrogenic surface marker expressions were checked by qRT-PCR and histologic assays. The extracted vesicles had a spherical morphology and a size of 44.25 ± 8.89 nm for Cho-EVs and 112.1 ± 10.10 nm for MSC-EVs. Both groups expressed the EV-specific surface markers CD9 and CD81. Higher expression of chondrogenic specified markers, especially collagen type II (COL II), and secretion of glycosaminoglycans (GAGs) and proteoglycans were observed in MSCs treated with 50 and 100 μg/ml MSC-EVs compared to the Cho-EVs. The results from the use of EVs, particularly MSC-EVs, with high chondrogenic ability will provide a basis for developing therapeutic agents for cartilage repair.

Chondrocyte secretome enriched microparticles encapsulated with the chondrocyte membrane to facilitate the chondrogenesis of BMSCs and reduce hypertrophy

Co-culture of chondrocytes and mesenchymal stem cells (MSCs) represents an effective way to stimulate the chondrogenesis of MSCs and reduce hypertrophy, but the limited donor site supply and the requirement of two-stage operations are among the major barriers of using autologous chondrocytes in clinical settings. With recent evidence indicating that the chondrogenic effects of the above co-culture mainly lied on the paracrine secretion, and that cell membranes also played crucial roles during the chondrocyte-MSC interaction, we fabricated a multifunctional design of "artificial chondrocytes", which consist of chondrocyte secretome enriched PLGA microparticles with the encapsulation of chondrocytes' membrane fragments. The artificial chondrocytes had shown a similar diameter and surface electrical charge to natural chondrocytes, with the preserved key chondrocyte membrane surface proteins and sustainedly released chondrogenic cytokines from the chondrocyte secretome to extend their effects in vivo. Consequently, the co-culture studies of artificial chondrocytes and bone marrow MSCs had shown the beneficial effects from both chondrocyte secretome and membrane fragments, which also synergistically facilitated the cell proliferation, chondrogenic gene expression, cartilaginous matrix production, and reduced phenotypic hypertrophy in vitro and in vivo. Together, this study has successfully developed the proof-of-concept design of "artificial chondrocytes", which could potentially conquer many major barriers of using natural chondrocytes and provided a novel synthetic-cell approach to current therapeutical strategies towards the functional regeneration of articular cartilage.

Evaluating potential of tissue-engineered cryogels and chondrocyte derived exosomes in articular cartilage repair

Treatment of articular cartilage injuries especially osteochondral tissue requires intervention of bioengineered scaffold. In this study, we investigated the potential of the tissue-engineered cryogel scaffold fabricated using cryogelation technology. Two types of cryogels viz. chitosan-gelatin-chondroitin sulfate (CGC) for articular cartilage and nano-hydroxyapatite-gelatin (HG) for subchondral bone were fabricated. Further, novel bilayer cryogel designed using single process fabrication of two layers (CGC as top layer and HG as the lower layer) was designed to mimic osteochondral unit. CGC cryogel was tested for their biocompatibility using the enzymatically isolated chondrcoytes from goat articular cartilage while HG cryogel was tested using pre-osteoblast cell line. Extracellular vesicles, specifically exosomes were isolated from the spent media of chondrocytes to validate their effect over cell proliferation and migration which are required for defect healing and infiltration respectively. These isolated exosomes were characterized and analyzed for confirming their size distribution profile and visualized morphologically using advanced microscopy techniques. For cartilage part, CGC cryogels were examined as delivery system for delivering exosomes at defect site, where 80% of release was observed in 72 h. Release of 18.7 µg chondroitin sulfate/mg cryogel was obtained in a period of one week from CGC cryogel (termed cryogel extract) which has chondroprotective effect. Further, effect of exosome concentration (10 and 20 µg/ml), CGC extract and combination of exosome and CGC extract (Exo-Ex) were assessed over the chondrocytes. In addition, in vitro scratch wound assay was performed to analyse the migration capacity over the micro-injury when treated with exosomes, cryogel extract and Exo-Ex. The overall results thus answer key questions of therapeutic potential of chondrocyte exosomes, cryogel extract in addition to potential of CGC and HG cryogel for osteochondral repair.

TMT-Based Proteomic Explores the Influence of DHEA on the Osteogenic Differentiation of hBMSCs

Dehydroepiandrosterone (DHEA) has been revealed to implicate in facilitating osteoblast differentiation of human bone marrow mesenchymal stem cells (hBMSCs) and inhibiting osteoporosis (OP). However, the underlying molecular mechanism remains largely unknown. Here, we induced osteogenic differentiation of hBMSCs derived from elders using an osteogenic induction medium with or without DHEA. The results showed that osteogenic induction medium (OIM) with DHEA could significantly promote the proliferation and osteogenic differentiation of hBMSCs than OIM alone. By using a Tandem Mass Tag (TMT) labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology, we screened out 604 differentially expressed proteins (DEPs) with at least one unique peptide were identified [524: OIM vs. complete medium (CM), and 547: OIM+DHEA vs. CM], among these proteins, 467 DEPs were shared in these two different comparative groups. Bioinformatic analysis revealed these DEPs are mainly enriched in metabolic pathways. Interestingly, the expression levels of the DEPs in the metabolic pathways showed a more noticeable change in the OIM+DHEA vs. CM group than OIM vs. CM group. Moreover, the protein-protein interaction (PPI) network analysis revealed that three potential proteins, ATP5B, MT-CYB, and MT-ATP6, involved in energy metabolism, might play a key role in osteogenic differentiation induced by OIM+DHEA. These findings offer a valuable clue for us to better understand the underlying mechanisms involved in osteoblast differentiation of hBMSCs caused by DHEA and assist in applying DHEA in hBMSCs-based therapy for osteogenic regeneration.

Is Extracellular Vesicle-Based Therapy the Next Answer for Cartilage Regeneration?

"Extracellular vesicles" (EVs) is a term gathering biological particles released from cells that act as messengers for cell-to-cell communication. Like cells, EVs have a membrane with a lipid bilayer, but unlike these latter, they have no nucleus and consequently cannot replicate. Several EV subtypes (e.g., exosomes, microvesicles) are described in the literature. However, the remaining lack of consensus on their specific markers prevents sometimes the full knowledge of their biogenesis pathway, causing the authors to focus on their biological effects and not their origins. EV signals depend on their cargo, which can be naturally sourced or altered (e.g., cell engineering). The ability for regeneration of adult articular cartilage is limited because this avascular tissue is partly made of chondrocytes with a poor proliferation rate and migration capacity. Mesenchymal stem cells (MSCs) had been extensively used in numerous in vitro and preclinical animal models for cartilage regeneration, and it has been demonstrated that their therapeutic effects are due to paracrine mechanisms involving EVs. Hence, using MSC-derived EVs as cell-free therapy tools has become a new therapeutic approach to improve regenerative medicine. EV-based therapy seems to show similar cartilage regenerative potential compared with stem cell transplantation without the associated hindrances (e.g., chromosomal aberrations, immunogenicity). The aim of this short review is to take stock of occurring EV-based treatments for cartilage regeneration according to their healing effects. The article focuses on cartilage regeneration through various sources used to isolate EVs (mature or stem cells among others) and beneficial effects depending on cargos produced from natural or tuned EVs.