Exosome-mediated Bidirectional Signaling between Mesenchymal Stem Cells and Chondrocytes for Enhanced Chondrogenesis

Dielectrophoretic Capture of Cancer-Derived Small-Extracellular-Vesicle-Bound Janus Nanoparticles via Lectin-Glycan Interaction

Glycosylation is closely related to cellular metabolism and disease progression. In particular, glycan levels in cancer cells and tissues increase during cancer progression. This upregulation of glycosylation in cancer cells may provide a basis for the development of new biomarkers for the targeting and diagnosis of specific cancers. Here, they developed a detection technology for pancreatic cancer cell-derived small extracellular vesicles (PC-sEVs) based on lectin-glycan interactions. Lectins specific for sialic acids are conjugated to Janus nanoparticles to induce interactions with PC-sEVs in a dielectrophoretic (DEP) system. PC-sEVs are selectively bound to the lectin-conjugated Janus nanoparticles (lectin-JNPs) with an affinity comparable to that of conventionally used carbohydrate antigen 19-9 (CA19-9) antibodies. Furthermore, sEVs-bound Lectin-JNPs (sEVs-Lec-JNPs) are manipulated between two electrodes to which an AC signal is applied for DEP capture. In addition, the proposed DEP system can be used to trap the sEVs-Lec-JNP on the electrodes. Their results, which are confirmed by lectin-JNPs using the proposed DEP system followed by target gene analysis, provide a basis for the development of a new early diagnostic marker based on the glycan characteristics of PC-sEVs. In turn, these novel detection methods could overcome the shortcomings of commercially available pancreatic cancer detection techniques.

Current and Novel Therapeutics for Articular Cartilage Repair and Regeneration

Articular cartilage repair is a sophisticated process that has is being recently investigated. There are several different approaches that are currently reported to promote cartilage repair, like cell-based therapies, biologics, and physical therapy. Cell-based therapies involve the using stem cells or chondrocytes, which make up cartilage, to promote the growth of new cartilage. Biologics, like growth factors, are also being applied to enhance cartilage repair. Physical therapy, like exercise and weight-bearing activities, can also be used to promote cartilage repair by inducing new cartilage growth and improving joint function. Additionally, surgical options like osteochondral autograft, autologous chondrocyte implantation, microfracture, and others are also reported for cartilage regeneration. In the current literature review, we aim to provide an up-to-date discussion about these approaches and discuss the current research status.

Chondrogenic Potential of Human Umbilical Cord Mesenchymal Stem Cells Cultured with Exosome-Depleted Fetal Bovine Serum in an Osteoarthritis Mouse Model

Osteoarthritis (OA) is characterized by the loss of articular cartilage and is also an age-related disease. Recently, stem cell therapy for cartilage repair has emerged. The stem cells need to be cultured with a fetal bovine serum (FBS)-supplemented medium. The effect of FBS-containing exosomes on the differentiation of human umbilical cord mesenchymal stem cells (HUCMSCs) is unknown. The morphology, proliferation, surface marker expressions, and trilineage differentiation ability of two groups of HUCMSCs, cultured with conventional (FBS) and exosome-depleted FBS (Exo(-)FBS), were evaluated. In a mouse OA model after two groups of HUCMSCs transplantation, the rotarod activity, histology, and immunohistochemistry (type II collagen, aggrecan, IL-1β, and MMP13) of the cartilage were evaluated. The Exo(-)FBS-cultured HUCMSCs, like FBS-cultured HUCMSCs, displayed classic MSC characteristics, including spindle-shaped morphology, surface marker expression (positive for CD44, CD73, CD90, CD105, and HLA-ABC and negative for CD34, CD45, and HLA-DR), and trilineage differentiation (chondrogenesis, osteogenesis, and adipogenesis). The Exo(-)FBS-cultured HUCMSCs proliferated significantly slower than those of the FBS-cultured HUCMSCs (p < 0.01). The trilineage gene expression of PPAR-γ, FABP4, APAL, type II collagen, aggrecan, and SOX9 was significantly increased in the Exo(-)FBS-cultured HUCMSCs than in the FBS-cultured HUCMSCs and undifferentiated controls. The Exo(-)FBS- and FBS-cultured HUCMSCs-transplanted mice showed a better rotarod activity than in the control OA mice (n = 3 in each group). A significant histological improvement in hyaline cartilage destruction after the transplantation of both types of FBS-cultured HUCMSCs was noted when compared with the OA knees. The Exo(-)FBS-cultured HUCMSCs-transplanted knees showed a higher International Cartilage Repair Society histological score (p < 0.05), staining intensity of type II collagen (p < 0.01), and aggrecan (p < 0.01) than in the control knees. Moreover, both types of the FBS-cultured HUCMSCs-transplanted knees significantly decreased the expression of MMP13 and IL-1β compared to that in the OA knees (p < 0.01). The Exo(-)FBS-cultured HUCMSCs harbor chondrogenic potential and attenuated cartilage destruction in a mouse OA model. Our study provides a basis for future clinical trials using Exo(-)FBS-cultured stem cells to treat OA.

Electrical Stimulation of Human Adipose-Derived Mesenchymal Stem Cells on O2 Plasma-Treated ITO Glass Promotes Osteogenic Differentiation

Electrical signals represent an essential form of cellular communication. For decades, electrical stimulation has been used effectively in clinical practice to enhance bone healing. However, the detailed mechanisms between electrical stimulation and bone healing are not well understood. In addition, there have been many difficulties in setting up a stable and efficient electrical stimulation system within the in vitro environment. Therefore, various conductive materials and electrical stimulation methods have been tested to establish an effective electrical stimulation system. Through these systems, many studies have been conducted on the effects of electrical stimulation on bone healing and osteogenic differentiation. However, previous studies were limited by the use of opaque conductive materials that obscure the cells; fluorescent observations and staining are known to be two of the critical methods to confirm the states of the cells. Indium tin oxide (ITO) glass is known to have excellent transparency and conductivity, but it is challenging to cultivate cells due to low cell adhesion characteristics. Therefore, we used O2 plasma treatment to increase the hydrophilicity and wettability of ITO glass. This enhanced cell affinity to the glass, providing a stable surface for the cells to attach. Then, electrical stimulation was applied with an amplitude range of 10 to 200 µA at a frequency of 10 Hz. Our results demonstrated that the osteogenic differentiation efficiency was maximized under the amplitude conditions of 10 µA and 50 µA. Accordingly, the results of our study suggest the development of an excellent platform in the field of biological research as a good tool to elucidate various mechanisms of cell bioactivity under electrical conditions.

Recent Developments and Current Applications of Organic Nanomaterials in Cartilage Repair

Regeneration of cartilage is difficult due to the unique microstructure, unique multizone organization, and avascular nature of cartilage tissue. The development of nanomaterials and nanofabrication technologies holds great promise for the repair and regeneration of injured or degenerated cartilage tissue. Nanomaterials have structural components smaller than 100 nm in at least one dimension and exhibit unique properties due to their nanoscale structure and high specific surface area. The unique properties of nanomaterials include, but are not limited to, increased chemical reactivity, mechanical strength, degradability, and biocompatibility. As an emerging nanomaterial, organic nanocomposites can mimic natural cartilage in terms of microstructure, physicochemical, mechanical, and biological properties. The integration of organic nanomaterials is expected to develop scaffolds that better mimic the extracellular matrix (ECM) environment of cartilage to enhance scaffold-cell interactions and improve the functionality of engineered tissue constructs. Next-generation hydrogel technology and bioprinting can be used not only for healing cartilage injury areas but also for extensive osteoarthritic degenerative changes within the joint. Although more challenges need to be solved before they can be translated into full-fledged commercial products, nano-organic composites remain very promising candidates for the future development of cartilage tissue engineering.

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.

Bone marrow mesenchymal stem cell-derived exosomes inhibit chondrocyte apoptosis and the expression of MMPs by regulating Drp1-mediated mitophagy

Osteoarthritis (OA) is a joint degenerative disease commonly seen in the elderly. Bone marrow mesenchymal stem cell-exosomes (BMSC-exosomes) are closely associated with the progression of OA. Here, we investigated whether BMSC-exosomes can affect OA development by regulating mitophagy. Primary rat chondrocytes were treated with advanced glycation end products (AGEs) to induce cell damage. The results of flow cytometry showed that AGEs treatment significantly promoted apoptosis of chondrocytes. AGEs treatment also enhanced the expression of matrix metalloproteinases (MMPs), MMP-3 and MMP-13, and dynamin-related protein 1 (Drp1) in chondrocytes. To investigate the impact of BMSC-exosomes on chondrocytes, chondrocytes were treated with BMSC-exosomes. AGEs-mediated increase of apoptosis and up-regulation of MMP-3, MMP-13, and Drp1 in chondrocytes were abrogated by BMSC-exosomes. Western blot analysis of autophagy-related proteins and Mito-Keima assay revealed that BMSC-exosome treatment elevated the expression of autophagy-related proteins, LC3-II/LC3-I and Beclin-1, and promoted mitophagy in the AGEs-treated chondrocytes. Moreover, Drp1 overexpression repressed the expression of LC3-II/LC3-I and Beclin-1, and enhanced apoptosis and the expression of MMP-3 and MMP-13 in AGEs-treated chondrocytes. BMSC-exosomes reversed the impact of Drp1 overexpression on AGEs-treated chondrocytes. In conclusion, this work demonstrates that BMSC-exosomes inhibit chondrocyte apoptosis and the expression of MMPs, which attributes to regulate Drp1-mediated mitophagy. Thus, BMSC-exosomes may be a potential treatment for OA.

Isolation of cabbage exosome-like nanovesicles and investigation of their biological activities in human cells

There are extensive studies on the applications of extracellular vesicles (EVs) produced in cell culture for therapeutic drug development. However, large quantities of EVs are needed for in vivo applications, which requires high production costs and time. Thus, the development of new EV sources is essential to facilitate their use. Accordingly, plant-derived exosome-like nanovesicles are an emerging alternative for culture-derived EVs. Until now, however, few studies have explored their biological functions and uses. Therefore, it is necessary to elucidate biological activities of plant-derived exosome-like nanovesicles and harness vesicles for biomedical applications. Herein, cabbage and red cabbage were used as nanovesicle sources owing to their easy cultivation. First, an efficient method for nanovesicle isolation from cabbage (Cabex) and red cabbage (Rabex) was developed. Furthermore, isolated nanovesicles were characterized, and their biological functions were assessed. Both Cabex and Rabex promoted mammalian cell proliferation and, interestingly, suppressed inflammation in immune cells and apoptosis in human keratinocytes and fibroblasts. Finally, therapeutic drugs were encapsulated in Cabex or Rabex and successfully delivered to human cells, demonstrating the potential of these vesicles as alternative drug delivery vehicles. Overall, the current results provide strong evidence for the wide application of Cabex and Rabex as novel therapeutic biomaterials.

Potential of Exosomes as Cell-Free Therapy in Articular Cartilage Regeneration: A Review

Treatment of cartilage defects such as osteoarthritis (OA) and osteochondral defect (OCD) remains a huge clinical challenge in orthopedics. OA is one of the most common chronic health conditions and is mainly characterized by the degeneration of articular cartilage, shown in the limited capacity for intrinsic repair. OCD refers to the focal defects affecting cartilage and the underlying bone. The current OA and OCD management modalities focus on symptom control and on improving joint functionality and the patient’s quality of life. Cell-based therapy has been evaluated for managing OA and OCD, and its chondroprotective efficacy is recognized mainly through paracrine action. Hence, there is growing interest in exploiting extracellular vesicles to induce cartilage regeneration. In this review, we explore the in vivo evidence of exosomes on cartilage regeneration. A total of 29 in vivo studies from the PubMed and Scopus databases were identified and analyzed. The studies reported promising results in terms of in vivo exosome delivery and uptake; improved cartilage morphological, histological, and biochemical outcomes; enhanced subchondral bone regeneration; and improved pain behavior following exosome treatment. In addition, exosome therapy is safe, as the included studies documented no significant complications. Modifying exosomal cargos further increased the cartilage and subchondral bone regeneration capacity of exosomes. We conclude that exosome administration is a potent cell-free therapy for alleviating OA and OCD. However, additional studies are needed to confirm the therapeutic potential of exosomes and to identify the standard protocol for exosome-based therapy in OA and OCD management.

Natural Polymeric Scaffolds for Tissue Engineering Applications

Natural polymeric scaffolds can be used for tissue engineering applications such as cell delivery and cell-free supporting of native tissues. This is because of their desirable properties such as; high biocompatibility, tunable mechanical strength and conductivity, large surface area, porous- and extracellular matrix (ECM)-mimicked structures. Specifically, their less toxicity and biocompatibility makes them suitable for several tissue engineering applications. For these reasons, several biopolymeric scaffolds are currently being explored for numerous tissue engineering applications. To date, research on the nature, chemistry, and properties of nanocomposite biopolymers are been reported, while the need for a comprehensive research note on more tissue engineering application of these biopolymers remains. As a result, this present study comprehensively reviews the development of common natural biopolymers as scaffolds for tissue engineering applications such as cartilage tissue engineering, cornea repairs, osteochondral defect repairs, and nerve regeneration. More so, the implications of research findings for further studies are presented, while the impact of research advances on future research and other specific recommendations are added as well.