RETRACTED: Human bone mesenchymal stem cells-derived exosomes overexpressing microRNA-26a-5p alleviate osteoarthritis via down-regulation of PTGS2

Potential of Exosomes for Diagnosis and Treatment of Joint Disease: Towards a Point-of-Care Therapy for Osteoarthritis of the Knee

In the knee joint, articular cartilage injury can often lead to osteoarthritis of the knee (OAK). Currently, no point-of-care treatment can completely address OAK symptoms and regenerate articular cartilage to restore original functions. While various cell-based therapies are being developed to address OAK, exosomes containing various components derived from their cells of origin have attracted attention as a cell-free alternative. The potential for exosomes as a novel point-of-care treatment for OAK has been studied extensively, especially in the context of intra-articular treatments. Specific exosomal microRNAs have been identified as possibly effective in treating cartilage defects. Additionally, exosomes have been studied as biomarkers through their differences in body fluid composition between joint disease patients and healthy subjects. Exosomes themselves can be utilized as a drug delivery system through their manipulation and encapsulation of specific contents to be delivered to specific cells. Through the combination of exosomes with tissue engineering, novel sustained release drug delivery systems are being developed. On the other hand, many of the functions and activities of exosomes are unknown and challenges remain for clinical applications. In this review, the possibilities of intra-articular treatments utilizing exosomes and the challenges in using exosomes in therapy are discussed.

MiR-129-5p shuttled by human synovial mesenchymal stem cell-derived exosomes relieves IL-1β induced osteoarthritis via targeting HMGB1

AIMS

To explore the therapeutic effect of miR-129-5p carried by exosomes from Human Synovial Mesenchymal Stem Cell (HS-MSC) on osteoarthritis(OA).

MATERIALS AND METHODS

The levels of miR-129-5p and high mobility group protein -1 (HMGB1) and interleukin-1β (IL-1β) in the joint fluid of OA patients were respectively detected via real-time quantitative reverse transcription-PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). IL-1β was taken to act on chondrocytes for the establishment of OA model in vitro. Ultracentrifugation was conducted to isolate HS-MSC exosomes (HS-MSC-Exo) from the supernatant. Western blot and ELISA were carried out to measure the expression of iNOS, COX2, MMP13, Collagen 2, TLR4, NF-κB, Caspase3, Bcl-2, HMGB1 in chondrocytes. Flow cytometry was conducted to detect the apoptosis of chondrocytes. Besides, bioinformatics was employed to predict the targeted relationship between miR-129-5p and HMGB1, which was further verified via dual luciferase activity experiments.

KEY FINDINGS

The results illustrated that miR-129-5p was decreased in OA patients and IL-1β-induced chondrocytes, while HMGB1 was notably upregulated. HS-MSC-Exo rich in miR-129-5p remarkably declined the inflammatory response and apoptosis of chondrocytes, while HS-MSC-Exo deficient in miR-129-5p increased the IL-1β-mediated inflammatory response and apoptosis of chondrocytes. In terms of mechanism, miR-129-5p targets the 3'UTR end of HMGB1 and inhibits IL-1β-mediated upregulation of HMGB1.

SIGNIFICANCE

In a word, this paper proved that miR-129-5p, existing in HS-MSC-Exo, can suppress the IL-1β-mediated OA by inhibiting HMGB1 release.

Preclinical Experimental Applications of miRNA Loaded BMSC Extracellular Vesicles

Bone marrow mesenchymal stem cells have been investigated for many years, especially for tissue regeneration, and have inherent limitations. One of the rapidly developing fields in the scientific world in recent years is extracellular vesicles. Especially, bone marrow mesenchymal stem cell originated extracellular vesicles are known to have positive contributions in tissue regeneration, and these extracellular vesicles have also been used as gene transfer systems for cellular therapy. Through gene expression analysis and bioinformatics tools, it is possible to determine which genes have changed in the targeted tissue or cell and which miRNAs that can correct this gene expression disorder. This approach connecting the stem cell, extracellular vesicles, epigenetics regulation and bioinformatics fields is one of the promising areas for the treatment of diseases in the future. With this review, it is aimed to present the studies carried out for the use of bone marrow stem cell-derived extracellular vesicles loaded with targeted miRNAs in different in vivo and in vitro human disease models and to discuss recent developments in this field.

Exosomes from microRNA-126 overexpressing mesenchymal stem cells promote angiogenesis by targeting the PIK3R2-mediated PI3K/Akt signalling pathway

microRNA‐126 (miR‐126), an endothelial‐specific miRNA, is associated with vascular homeostasis and angiogenesis. However, the efficiency of miR‐126‐based treatment is partially compromised due to the low efficiency of miRNA delivery in vivo. Lately, exosomes have emerged as a natural tool for therapeutic molecule delivery. Herein, we investigated whether exosomes derived from bone marrow mesenchymal stem cells (BMMSCs) can be utilized to deliver miR‐126 to promote angiogenesis. Exosomes were isolated from BMMSCs overexpressed with miR‐126 (Exo‐miR‐126) by ultracentrifugation. In vitro study, Exo‐miR‐126 treatment promoted the proliferation, migration and angiogenesis of human umbilical vein endothelial cells (HUVECs). Furthermore, the gene/protein expression of angiogenesis‐related vascular endothelial growth factor (VEGF) and angiotensin‐1 (Ang‐1) were up‐regulated after incubation with Exo‐miR‐126. Additionally, the expression level of phosphoinositol‐3 kinase regulatory subunit 2 (PIK3R2) showed an inverse correlation with miR‐126 in HUVECs. Particularly, the Exo‐miR‐126 treatment contributed to enhanced angiogenesis of HUVECs by targeting PIK3R2 to activate the PI3K/Akt signalling pathway. Similarly, Exo‐miR‐126 administration profoundly increased the number of newly formed capillaries in wound sites and accelerated the wound healing in vivo. The results demonstrate that exosomes derived from BMMSCs combined with miR‐126 may be a promising strategy to promote angiogenesis.

microRNA-26a Directly Targeting MMP14 and MMP16 Inhibits the Cancer Cell Proliferation, Migration and Invasion in Cutaneous Squamous Cell Carcinoma

Purpose

To investigate the specific effect and underlying mechanism of microRNA-26a-5p (miR-26a) in cutaneous squamous cell carcinoma (CSCC).

Methods

miR-26a and MMP14/16 mRNA expression were detected by qRT-PCR analysis. Functional experiments were used to detect the role of miR-26a on CSCC progression. Western blot was used for protein detection. Luciferase assay was used to detect miR-26a directly targeting MMP14 and MMP16. Xenograft nude mice model was used to determine the effect of miR-26a on tumorigenesis.

Results

miR-26a was decreased in CSCC tissues and cells. Forced miR-26a suppressed the progression of SCL-1 and A431 cells. Furthermore, miR-26a directly targeted MMP14 and MMP16 to inhibit their expression. Forced expression of MMP14 and MMP16 removed the miR-26a’s inhibitory effect on CSCC development. The in vivo tumor growth assay showed that miR-26a suppressed CSCC tumorigenesis by targeting MMP14 and MMP16.

Conclusion

Our study suggested miR-26a inhibits cancer cell proliferation, migration and invasion in CSCC by targeting MMP14 and MMP16. 

Mesenchymal stem cell-derived exosomes: Toward cell-free therapeutic strategies in regenerative medicine

Mesenchymal stem cells (MSCs) are multipotent stem cells with marked potential for regenerative medicine because of their strong immunosuppressive and regenerative abilities. The therapeutic effects of MSCs are based in part on their secretion of biologically active factors in extracellular vesicles known as exosomes. Exosomes have a diameter of 30-100 nm and mediate intercellular communication and material exchange. MSC-derived exosomes (MSC-Exos) have potential for cell-free therapy for diseases of, for instance, the kidney, liver, heart, nervous system, and musculoskeletal system. Hence, MSC-Exos are an alternative to MSC-based therapy for regenerative medicine. We review MSC-Exos and their therapeutic potential for a variety of diseases and injuries.

Inhibiting Rab27a in renal tubular epithelial cells attenuates the inflammation of diabetic kidney disease through the miR-26a-5p/CHAC1/NF-kB pathway

The effect of exosomes on receptor cells participating in intercellular communication has been extensively studied, but the effect of exosomes on donor cells remains unclear. It has been reported that exosomes secreted by renal proximal tubular epithelial cells (PTECs) under different stimuli accelerate acute and chronic kidney diseases. This study aimed to explore whether inhibiting exosomal secretion in PTECs by knocking out Rab27a, a key exosome regulatory gene, inhibits the excessive inflammatory response in PTECs and delays diabetic kidney disease (DKD). First, we proved that the bovine serum albumin (BSA)-induced inflammatory response in HK-2 cells was inhibited by knocking out Rab27a and that Rab27a, IL-6, TNF-α and COL-1 expression was markedly increased in an HFD/STZ-induced diabetic mouse model. Furthermore, miR-26a-5p expression in exosomes secreted by BSA-treated HK-2 cells was significantly increased but correspondingly decreased in the cells; after knocking out Rab27a, miR-26a-5p levels in the cells rebounded. Next, we confirmed that a miR-26a-5p mimic suppressed the inflammatory response, while a miR-26a-5p inhibitor accelerated the inflammatory response. Then, we found that miR-26a-5p targets the 3'-untranslated region (UTR) of CHAC1. Furthermore, the inflammatory response and NF-κB signalling pathway activation induction by the miR-26a-5p inhibitor were abolished by CHAC1 knockout. Therefore, we conclude that inhibiting exosome secretion by BSA-induced PTECs promotes miR-26a-5p expression in cells, thereby inhibiting the CHAC1/NF-κB pathways to prevent the inflammatory response in PTECs and delaying the development of DKD. This study provides new insight into the pathogenic mechanism of exosomes and a new therapeutic target for DKD.

MicroRNAs in Synovial Pathology Associated With Osteoarthritis

Osteoarthritis (OA) is the most common type of arthritis, a disease that affects the entire joint. The relative involvement of each tissue, and their interactions, add to the complexity of OA, hampering our understanding of the underlying molecular mechanisms, and the generation of a disease modifying therapy. The synovium is essential in maintaining joint homeostasis, and pathologies associated with the synovium contribute to joint destruction, pain and stiffness in OA. MicroRNAs (miRNAs) are post-transcriptional regulators dysregulated in OA tissues including the synovium. MiRNAs are important contributors to OA synovial changes that have the potential to improve our understanding of OA and to act as novel therapeutic targets. The purpose of this review is to summarize and integrate current published literature investigating the roles that miRNAs play in OA-related synovial pathologies including inflammation, matrix deposition and cell proliferation.

Exosomes: roles and therapeutic potential in osteoarthritis

Exosomes participate in many physiological and pathological processes by regulating cell-cell communication, which are involved in numerous diseases, including osteoarthritis (OA). Exosomes are detectable in the human articular cavity and were observed to change with OA progression. Several joint cells, including chondrocytes, synovial fibroblasts, osteoblasts, and tenocytes, can produce and secrete exosomes that influence the biological effects of targeted cells. In addition, exosomes from stem cells can protect the OA joint from damage by promoting cartilage repair, inhibiting synovitis, and mediating subchondral bone remodeling. This review summarizes the roles and therapeutic potential of exosomes in OA and discusses the perspectives and challenges related to exosome-based treatment for OA patients in the future.

The Treatment of Cartilage Damage Using Human Mesenchymal Stem Cell-Derived Extracellular Vesicles: A Systematic Review of in vivo Studies

Damage to joints through injury or disease can result in cartilage loss, which if left untreated can lead to inflammation and ultimately osteoarthritis. There is currently no cure for osteoarthritis and management focusses on symptom control. End-stage osteoarthritis can be debilitating and ultimately requires joint replacement in order to maintain function. Therefore, there is growing interest in innovative therapies for cartilage repair. In this systematic literature review, we sought to explore the in vivo evidence for the use of human Mesenchymal Stem Cell-derived Extracellular Vesicles (MSC-EVs) for treating cartilage damage. We conducted a systematic literature review in accordance with the PRISMA protocol on the evidence for the treatment of cartilage damage using human MSC-EVs. Studies examining in vivo models of cartilage damage were included. A risk of bias analysis of the studies was conducted using the SYRCLE tool. Ten case-control studies were identified in our review, including a total of 159 murine subjects. MSC-EVs were harvested from a variety of human tissues. Five studies induced osteoarthritis, including cartilage loss through surgical joint destabilization, two studies directly created osteochondral lesions and three studies used collagenase to cause cartilage loss. All studies in this review reported reduced cartilage loss following treatment with MSC-EVs, and without significant complications. We conclude that transplantation of MSC-derived EVs into damaged cartilage can effectively reduce cartilage loss in murine models of cartilage injury. Additional randomized studies in animal models that recapitulates human osteoarthritis will be necessary in order to establish findings that inform clinical safety in humans.

Mesenchymal Stem/Stromal Cell-Derived Exosomes for Immunomodulatory Therapeutics and Skin Regeneration

Exosomes are nano-sized vesicles that serve as mediators for cell-to-cell communication. With their unique nucleic acids, proteins, and lipids cargo compositions that reflect the characteristics of producer cells, exosomes can be utilized as cell-free therapeutics. Among exosomes derived from various cellular origins, mesenchymal stem cell-derived exosomes (MSC-exosomes) have gained great attention due to their immunomodulatory and regenerative functions. Indeed, many studies have shown anti-inflammatory, anti-aging and wound healing effects of MSC-exosomes in various in vitro and in vivo models. In addition, recent advances in the field of exosome biology have enabled development of specific guidelines and quality control methods, which will ultimately lead to clinical application of exosomes. This review highlights recent studies that investigate therapeutic potential of MSC-exosomes and relevant mode of actions for skin diseases, as well as quality control measures required for development of exosome-derived therapeutics.

The Use of Peripheral Blood-Derived Stem Cells for Cartilage Repair and Regeneration In Vivo: A Review

Background

Peripheral blood (PB) is a potential source of chondrogenic progenitor cells that can be used for cartilage repair and regeneration. However, the cell types, isolation and implantation methods, seeding dosage, ultimate therapeutic effect, and in vivo safety remain unclear.

Methods

PubMed, Embase, and the Web of Science databases were systematically searched for relevant reports published from January 1990 to December 2019. Original articles that used PB as a source of stem cells to repair cartilage in vivo were selected for analysis.

Results

A total of 18 studies were included. Eight human studies used autologous nonculture-expanded PB-derived stem cells (PBSCs) as seed cells with the blood cell separation isolation method, and 10 animal studies used autologous, allogenic or xenogeneic culture-expanded PB-derived mesenchymal stem cells (PB-MSCs), or nonculture-expanded PBSCs as seed cells. Four human and three animal studies surgically implanted cells, while the remaining studies implanted cells by single or repeated intra-articular injections. 121 of 130 patients (in 8 human clinical studies), and 230 of 278 animals (in 6 veterinary clinical studies) using PBSCs for cartilage repair achieved significant clinical improvement. All reviewed articles indicated that using PB as a source of seed cells enhances cartilage repair in vivo without serious adverse events.

Conclusion

Autologous nonculture-expanded PBSCs are currently the most commonly used cells among all stem cell types derived from PB. Allogeneic, autologous, and xenogeneic PB-MSCs are more widely used in animal studies and are potential seed cell types for future applications. Improving the mobilization and purification technology, and shortening the culture cycle of culture-expanded PB-MSCs will obviously promote the researchers' interest. The use of PBSCs for cartilage repair and regeneration in vivo are safe. PBSCs considerably warrant further investigations due to their superiority and safety in clinical settings and positive effects despite limited evidence in humans.