Inhibition of miR-449a Promotes Cartilage Regeneration and Prevents Progression of Osteoarthritis in In Vivo Rat Models

Enhancing collagen based nanoemulgel for effective topical delivery of Aceclofenac and Citronellol oil: Formulation, optimization, in-vitro evaluation, and in-vivo osteoarthritis study with a focus on HMGB-1/RAGE/NF-κB pathway, Klotho, and miR-499a

The majority of conventional osteoarthritis (OA) treatments are based on molecular adjustment of certain signaling pathways associated with osteoarthritis (OA) pathogenesis, however there is a significant need to search for more effective and safe treatments. This study centers around formulating Aceclofenac (ACF) with high bioavailability in combination with Citronellol oil and collagen. The optimal concentrations of Citronellol oil/D-Limonene oil, Tween 80, and Transcutol HP were determined using a pseudoternary phase diagram. The formulated nanoemulsions were studied for thermophysical stability. Thermodynamically stable formula were analyzed for droplet size, zeta potential, and in-vitro permeation. Then, collagen based nanoemulsion were prepared to capitalize on its efficacy in reducing osteoarthritis side effects and characterized for nano size properties. Formulae F10 and F10C were chosen as optimum nanosize formula. Hense, they were prepared and characterized as nanoemulgel dosage form. The nanoemulgel formulae F10NEG1 and F10CNEG1 showed reasonable viscosity and spreadability, with complete drug release after 4 h. These formulae were chosen for further In vivo anti-OA study. Collagen based ACF/citronellol emugel were able to modulate HMGB-1/RAGE/NF-κB pathway, mitigating the production of inflammatory cytokine TNF-α. They were also able to modulate Klotho and miR-499, reducing serum CTXII and COMP, by reducing the cartilage destruction. Histological investigations validated the efficacy, safety, and superiority of Aceclofenac in combination with Citronellol oil and collagen (F10CNEG1) over solo the treated group (F10NEG1 and blank). Hence, the findings of the current work encourage the use of this promising combined formula in treatment of OA patients.

Engineering approaches for RNA-based and cell-based osteoarthritis therapies

Osteoarthritis (OA) is a chronic, debilitating disease that substantially impairs the quality of life of affected individuals. The underlying mechanisms of OA are diverse and are becoming increasingly understood at the systemic, tissue, cellular and gene levels. However, the pharmacological therapies available remain limited, owing to drug delivery barriers, and consist mainly of broadly immunosuppressive regimens, such as corticosteroids, that provide only short-term palliative benefits and do not alter disease progression. Engineered RNA-based and cell-based therapies developed with synthetic chemistry and biology tools provide promise for future OA treatments with durable, efficacious mechanisms of action that can specifically target the underlying drivers of pathology. This Review highlights emerging classes of RNA-based technologies that hold potential for OA therapies, including small interfering RNA for gene silencing, microRNA and anti-microRNA for multi-gene regulation, mRNA for gene supplementation, and RNA-guided gene-editing platforms such as CRISPR-Cas9. Various cell-engineering strategies are also examined that potentiate disease-dependent, spatiotemporally regulated production of therapeutic molecules, and a conceptual framework is presented for their application as OA treatments. In summary, this Review highlights modern genetic medicines that have been clinically approved for other diseases, in addition to emerging genome and cellular engineering approaches, with the goal of emphasizing their potential as transformative OA treatments.

Surgical suction filter-derived bone graft displays osteogenic miRNA and mRNA patterns

PURPOSE

Recently, a surgical suction filter device was introduced which aims at generating a suction filter-derived bone grafting substitute (SF-BGS). The osteogenic capacity of this grafting material, however, is unclear. MicroRNAs (miRNAs) and osteogenic mRNAs may influence these processes. The aim of this study was therefore to investigate the quality of the SF-BGS by determining the expression of miRNAs and osteogenic mRNAs.

METHODS

Samples were collected during non-union surgery. Upon exposure of the intramedullary canal, the surgical vacuum system was fitted with the suction filter device containing collagen complex and synthetic β-TCP: (Ca3(PO4)2, granule size 5-8 mm, total volume 10 mL (Cerasorb Foam®, Curasan AG, Kleinostheim, Germany). As a control, venous blood was used as in current clinical practice. Samples were snap-frozen and mechanically disrupted. MiRNAs and mRNAs were isolated, transcribed, and pooled for qPCR analysis. Lastly, mRNA targets were determined through in silico target analyses.

RESULTS

The study population consisted of seven patients with a posttraumatic long bone non-union (4♀; mean age 54 ± 16 years). From the array data, distinct differences in miRNA expression were found between the SF-BGS and control samples. Osteogenic marker genes were overall upregulated in the SF-BGS. Qiagen IPA software identified 1168 mRNA targets for 43 of the overall deregulated miRNAs.

CONCLUSION

This study revealed distinctly deregulated and exclusively expressed osteogenic miRNAs in SF-BGS, as well as overall enhanced osteogenic marker gene expression, as compared to the venous blood control group. These expression profiles were not seen in control samples, indicating that the derived material displays an osteogenic profile. It may therefore be a promising tool to generate a BGS or graft extender when needed.

Recent progress in the manipulation of biochemical and biophysical cues for engineering functional tissues

Tissue engineering (TE) is currently considered a cutting-edge discipline that offers the potential for developing treatments for health conditions that negatively affect the quality of life. This interdisciplinary field typically involves the combination of cells, scaffolds, and appropriate induction factors for the regeneration and repair of damaged tissue. Cell fate decisions, such as survival, proliferation, or differentiation, critically depend on various biochemical and biophysical factors provided by the extracellular environment during developmental, physiological, and pathological processes. Therefore, understanding the mechanisms of action of these factors is critical to accurately mimic the complex architecture of the extracellular environment of living tissues and improve the efficiency of TE approaches. In this review, we recapitulate the effects that biochemical and biophysical induction factors have on various aspects of cell fate. While the role of biochemical factors, such as growth factors, small molecules, extracellular matrix (ECM) components, and cytokines, has been extensively studied in the context of TE applications, it is only recently that we have begun to understand the effects of biophysical signals such as surface topography, mechanical, and electrical signals. These biophysical cues could provide a more robust set of stimuli to manipulate cell signaling pathways during the formation of the engineered tissue. Furthermore, the simultaneous application of different types of signals appears to elicit synergistic responses that are likely to improve functional outcomes, which could help translate results into successful clinical therapies in the future.

Prophylactic administration of miR-451 inhibitor decreases osteoarthritis severity in rats

Transfection of chondrocytes with microRNA-451(miR-451), present in growth zone cartilage of the growth plate, upregulates production of enzymes association with extracellular matrix degradation. miR-451 is also present in articular cartilage and exacerbates IL-1β effects in articular chondrocytes. Moreover, when osteoarthritis (OA) was induced in Sprague Dawley rats via bilateral anterior cruciate ligament transection (ACLT), miR-451 expression was increased in OA cartilage compared to control, suggesting its inhibition might be used to prevent or treat OA. To examine the prophylactic and therapeutic potential of inhibiting miR-451, we evaluated treatment with miR-451 power inhibitor (451-PI) at the onset of joint trauma and treatment after OA had developed. The prophylactic animal cohort received twice-weekly intra-articular injections of either 451-PI or a negative control (NC-PI) beginning on post-surgical day 3. OA was allowed to develop for 24 days in the therapeutic cohort before beginning injections. All rats were killed on day 45. Micro-CT, histomorphometrics, OARSI scoring, and muscle force testing were performed on samples. 451-PI mitigated OA progression compared to NC-PI limbs in the prophylactic cohort based on histomorphometric analysis and OARSI scoring, but no differences were detected by micro-CT. 451-PI treatment beginning 24 days post-surgery was not able to reduce OA severity. Prophylactic administration of 451-PI mitigates OA progression in a post-trauma ACLT rat model supporting its potential to prevent OA development following an ACLT injury clinically.

State of the Art: The Immunomodulatory Role of MSCs for Osteoarthritis

Osteoarthritis (OA) has generally been introduced as a degenerative disease; however, it has recently been understood as a low-grade chronic inflammatory process that could promote symptoms and accelerate the progression of OA. Current treatment strategies, including corticosteroid injections, have no impact on the OA disease progression. Mesenchymal stem cells (MSCs) based therapy seem to be in the spotlight as a disease-modifying treatment because this strategy provides enlarged anti-inflammatory and chondroprotective effects. Currently, bone marrow, adipose derived, synovium-derived, and Wharton's jelly-derived MSCs are the most widely used types of MSCs in the cartilage engineering. MSCs exert immunomodulatory, immunosuppressive, antiapoptotic, and chondrogenic effects mainly by paracrine effect. Because MSCs disappear from the tissue quickly after administration, recently, MSCs-derived exosomes received the focus for the next-generation treatment strategy for OA. MSCs-derived exosomes contain a variety of miRNAs. Exosomal miRNAs have a critical role in cartilage regeneration by immunomodulatory function such as promoting chondrocyte proliferation, matrix secretion, and subsiding inflammation. In the future, a personalized exosome can be packaged with ideal miRNA and proteins for chondrogenesis by enriching techniques. In addition, the target specific exosomes could be a gamechanger for OA. However, we should consider the off-target side effects due to multiple gene targets of miRNA.

Mouse microRNA signatures in joint ageing and post-traumatic osteoarthritis

OBJECTIVE

This study investigated mice serum and joint microRNA expression profiles in ageing and osteoarthritis to elucidate the role of microRNAs in the development and progression of disease, and provide biomarkers for ageing and osteoarthritis.

DESIGN

Whole joints and serum samples were collected from C57BL6/J male mice and subjected to small RNA sequencing. Groups used included; surgically-induced post-traumatic osteoarthritis, (DMM; 24 months-old); sham surgery (24 months-old); old mice (18 months-old); and young mice (8 months-old). Differentially expressed microRNAs between the four groups were identified and validated using real-time quantitative PCR. MicroRNA differential expression data was used for target prediction and pathway analysis.

RESULTS

In joint tissues, miR-140-5p, miR-205-5p, miR-682, miR-208b-3p, miR-499-5p, miR-455-3p and miR-6238 were differentially expressed between young and old groups; miR-146a-5p, miR-3474, miR-615-3p and miR-151-5p were differentially expressed between DMM and Sham groups; and miR-652-3p, miR-23b-3p, miR-708-5p, miR-5099, miR-23a-3p, miR-214-3p, miR-6238 and miR-148-3p between the old and DMM groups. The number of differentially expressed microRNAs in serum was higher, some in common with joint tissues including miR-140-5p and miR-455-3p between young and old groups; and miR-23b-3p, miR-5099 and miR-6238 between old and DMM groups.We confirmed miR-140-5p, miR-499-5p and miR-455-3p expression to be decreased in old mouse joints compared to young, suggesting their potential use as biomarkers of joint ageing in mice.

CONCLUSIONS

MiR-140-5p, miR-499-5p and miR-455-3p could be used as joint ageing biomarkers in mice. Further research into these specific molecules in human tissues is now warranted to check their potential suitability as human biomarkers of ageing.

Mesenchymal Stem Cell-Derived Exosomes and MicroRNAs in Cartilage Regeneration: Biogenesis, Efficacy, miRNA Enrichment and Delivery

Exosomes are the small extracellular vesicles secreted by cells for intercellular communication. Exosomes are rich in therapeutic cargos such as microRNA (miRNA), long non-coding RNA (lncRNA), small interfering RNA (siRNA), DNA, protein, and lipids. Recently, many studies have focused on miRNAs as a promising therapeutic factor to support cartilage regeneration. Exosomes are known to contain a substantial amount of a variety of miRNAs. miRNAs regulate the post-transcriptional gene expression by base-pairing with the target messenger RNA (mRNA), leading to gene silencing. Several exosomal miRNAs have been found to play a role in cartilage regeneration by promoting chondrocyte proliferation and matrix secretion, reducing scar tissue formation, and subsiding inflammation. The exosomal miRNA cargo can be modulated using techniques such as cell transfection and priming as well as post-secretion modifications to upregulate specific miRNAs to enhance the therapeutic effect. Exosomes are delivered to the joints through direct injection or via encapsulation within a scaffold for sustained release. To date, exosome therapy for cartilage injuries has yet to be optimized as the ideal cell source for exosomes, and the dose and method of delivery have yet to be identified. More importantly, a deeper understanding of the role of exosomal miRNAs in cartilage repair is paramount for the development of more effective exosome therapy.

Circ_0128846/miR-140-3p/JAK2 Network in Osteoarthritis Development

Circular RNAs (circRNAs) titrate the function of microRNAs (miRNAs), regulate transcription, and interfere with splicing. This study attempted to confirm the role of a novel circRNA circ_0128846 during osteoarthritis (OA) progression. Tissues and chondrocytes were isolated from OA patients. Overexpression and knockdown of target genes were generated using cell transfection and siRNA interference. Expression levels of genes were measured by qRT-PCR, Western blot, and immunohistochemistry, respectively. The interactions among circ_0128846, miR-140-3p, and JAK2 were verified by bioinformatics prediction, a dual-luciferase reporter assay, and RNA immunoprecipitation assay. The role of circ_0128846 in vivo was confirmed by the construction of experimental OA rats. Pathological changes were evaluated by hematoxylin and eosin and Safranin O staining. In OA patients, the level of circ_0128846 and JAK2 were up-regulated with down-regulated level of miR-140-3p. Circ_0128846 was principally located in the cytoplasm. Circ_0128846 silence enhanced cells viability, but reduced apoptosis rate and inflammatory response, which was obviously reversed by miR-140-3p knockdown. The overexpression of JAK2 reversed the effects of miR-140-3p on cell phenotypes. Circ_0128846 silence suppressed the level of MMP-13 and promoted the expression of collagen II by up-regulating miR-140-3p and down-regulating JAK2 in OA cells. Results of animal experiments demonstrated that circ_0128846 silence promoted collagen II expression and attenuated the OA progression by regulating the miR-140-3p/JAK2 axis. Circ_0128846 contributes to OA development through acting as a sponge RNA for miR-140-3p and thereby increasing JAK2 expression. Results indicated that targeting circ_0128846 may have the potential to alleviate OA progression.Abbreviations:circRNAs: Circular RNAs; miRNAs: microRNAs; OA: osteoarthritis; RIP: RNA immunoprecipitation; H&E: hematoxylin and eosin; ncRNAs: noncoding RNAs; ceRNA: competitive endogenous RNA; DMEM: Dulbecco's modified Eagle's medium; PBS: phosphate buffered saline; OE-circ_0128846: overexpression vector for circ_0128846; pcDNA3.1-JAK2: pcDNA3.1 overexpression vector for Janus kinase 2; NC: negative control; CCK-8: Cell Counting Kit-8; PI: propidium iodide; WT: Wild-type; mutants (MUT); SD rats: Sprague Dawley rats; DMM: destabilization of medial meniscus; IHC: immunohistochemistry; DAB: diaminobenzene; pre-Mrna: precursor mRNA.

The Interaction between microRNAs and the Wnt/β-Catenin Signaling Pathway in Osteoarthritis

Osteoarthritis (OA) is a chronic disease affecting the whole joint, which still lacks a disease-modifying treatment. This suggests an incomplete understanding of underlying molecular mechanisms. The Wnt/β-catenin pathway is involved in different pathophysiological processes of OA. Interestingly, both excessive stimulation and suppression of this pathway can contribute to the pathogenesis of OA. microRNAs have been shown to regulate different cellular processes in different diseases, including the metabolic activity of chondrocytes and osteocytes. To bridge these findings, here we attempt to give a conclusive overview of microRNA regulation of the Wnt/β-catenin pathway in bone and cartilage, which may provide insights to advance the development of miRNA-based therapeutics for OA treatment.

Oligonucleotide Therapies in the Treatment of Arthritis: A Narrative Review

Osteoarthritis (OA) and rheumatoid arthritis (RA) are two of the most common chronic inflammatory joint diseases, for which there remains a great clinical need to develop safer and more efficacious pharmacological treatments. The pathology of both OA and RA involves multiple tissues within the joint, including the synovial joint lining and the bone, as well as the articular cartilage in OA. In this review, we discuss the potential for the development of oligonucleotide therapies for these disorders by examining the evidence that oligonucleotides can modulate the key cellular pathways that drive the pathology of the inflammatory diseased joint pathology, as well as evidence in preclinical in vivo models that oligonucleotides can modify disease progression.

Candidates for Intra-Articular Administration Therapeutics and Therapies of Osteoarthritis

Osteoarthritis (OA) of the knee is a disease that significantly decreases the quality of life due to joint deformation and pain caused by degeneration of articular cartilage. Since the degeneration of cartilage is irreversible, intervention from an early stage and control throughout life is important for OA treatment. For the treatment of early OA, the development of a disease-modifying osteoarthritis drug (DMOAD) for intra-articular (IA) injection, which is attracting attention as a point-of-care therapy, is desired. In recent years, the molecular mechanisms involved in OA progression have been clarified while new types of drug development methods based on gene sequences have been established. In addition to conventional chemical compounds and protein therapeutics, the development of DMOAD from the new modalities such as gene therapy and oligonucleotide therapeutics is accelerating. In this review, we have summarized the current status and challenges of DMOAD for IA injection, especially for protein therapeutics, gene therapy, and oligonucleotide therapeutics.

Down-regulation of microRNA-203a suppresses IL-1β-induced inflammation and cartilage degradation in human chondrocytes through Smad3 signaling

Osteoarthritis (OA) is a chronic and prevalent degenerative musculoskeletal disorder, which is characterized by articular cartilage degradation and joint inflammation. MicroRNA-203a (miR-203a) has been shown to be involved in multiple pathological processes during OA, but little is known about its function in chondrocyte extracellular matrix (ECM) degradation. In the present study, we aimed to elucidate the effects of miR-203a on articular cartilage degradation and joint inflammation. We observed that the miR-203a level was significantly up-regulated in OA tissues and in an in vitro model of OA, respectively. Inhibition of miR-203a significantly alleviated the interleukin (IL)-1β-induced inflammatory response and ECM degradation in chondrocytes. Moreover, mothers against decapentaplegic homolog 3 (Smad3), a key factor in maintaining chondrocyte homeostasis, was identified as a putative target of miR-203a in chondrocytes. More importantly, inhibition of Smad3 impaired the inhibitory effects of the miR-203a on IL-1β-induced inflammatory response and ECM degradation. Collectively, these results demonstrated that miR-203a may contribute to articular cartilage degradation of OA by targeting Smad3, suggesting a novel therapeutic target for the treatment of OA.

MicroRNAs and fracture healing: Pre-clinical studies

During the past several years, pre-clinical experiments have established that microRNAs (miRNAs), small non-coding RNAs, serve as key regulatory molecules of fracture healing. Their easy modulation with agonists and antagonists make them highly desirable targets for future therapeutic strategies, especially for pathophysiologic fractures that either do not heal (nonunions) or are delayed. It is now well documented that these problematic fractures lead to human suffering and impairment of life quality. Additionally, financial difficulties are also encountered as work productivity decreases and income is reduced. Moreover, targeting miRNAs may also be an avenue to enhancing normal physiological fracture healing. Herein we present the most current knowledge of the involvement of miRNAs during fracture healing in pre-clinical studies. Following a brief description on the nature of miRNAs and of the fracture healing process, we present data from studies focusing specifically, on miRNA regulation of osteoblast differentiation and osteogenesis (within the context of known signaling pathways), chondrocytes, angiogenesis, and apoptosis, all critical to successful bone repair. Further, we also discuss miRNAs and exosomes. We hope that this manuscript serves as a comprehensive review that will facilitate basic/translational scientists in the orthopaedic arena to realize and further decipher the biological and future therapeutic impact of these small regulatory RNA molecules, especially as they relate to the molecular events of each of the major phases of fracture healing.

lncRNA-CRNDE regulates BMSC chondrogenic differentiation and promotes cartilage repair in osteoarthritis through SIRT1/SOX9

Osteoarthritis (OA) is the most common chronic and degenerative joint disease. Although traditional OA medications can partially relieve pain, these medications cannot completely cure OA. Therefore, it is particularly important to find an effective treatment for OA. This study explored the function of long non-coding RNA (lncRNA)-colorectal neoplasia differentially expressed gene (CRNDE) in the chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and the underlying molecular mechanism, aiming to develop a new treatment method for osteoarthritis. BMSCs were isolated from rat bone marrow using the gradient centrifugation method. And BMSC chondrogenic differentiation was induced with chondrogenic medium. The expression of lncRNA-CRNDE was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Silent information regulator factor 2-related enzyme 1 (SIRT1) and cartilage marker genes Aggrecan and collagen 2 (α1) protein expression were researched using western blot. Alcian blue staining was employed to examine the content of cartilage matrix proteoglycan glycosaminoglycan (GAG). The interaction between lncRNA-CRNDE and SIRT1 was detected by RNA pull-down and RNA immunoprecipitation (RIP) assay. Ubiquitination experiments were performed to measure the ubiquitination level of SIRT1. The combination between SMAD ubiquitination regulatory factor 2 (SMURF2) and SIRT1, as well as SRY-related high-mobility-group box 9 (SOX9) and collagen 2 (α1) promoter, was detected by Co-immunoprecipitation or ChIP. With the prolongation of induction time, the expression of lncRNA-CRNDE, SIRT1, cartilage marker genes Aggrecan and collagen 2 (α1) in BMSC osteogenic differentiation was gradually increased. Also, the content of cartilage matrix proteoglycan GAG was gradually elevated with the extension of the induction time. Further increase in the expression of SIRT1, cartilage marker genes Aggrecan and collagen 2 (α1) by overexpression of lncRNA-CRNDE also indicated elevated GAG content. RNA pull-down and RIP assay confirmed the binding between lncRNA-CRNDE and SIRT1. qRT-PCR and western blot showed that interference with lncRNA-CRNDE significantly inhibited the protein expression of SIRT1. BMSCs transfected with si-CRNDE increased ubiquitination levels of SIRT1 mediated by the E3 ligase SMURF2, leading to the reduced protein stability of SIRT1. However, overexpression of lncRNA-CRNDE increased the binding ability of SOX9 and collagen 2 (α1) promoter, which was reversed by the simultaneous transfection of CRNDE overexpression (pcDNA-CRNDE) and SIRT1 small interfering RNA (si-SIRT1). lncRNA-CRNDE regulates BMSC chondrogenic differentiation to promote cartilage repair in osteoarthritis through SIRT1/SOX9.

Equine synovial fluid small non-coding RNA signatures in early osteoarthritis

BACKGROUND

Osteoarthritis remains one of the greatest causes of morbidity and mortality in the equine population. The inability to detect pre-clinical changes in osteoarthritis has been a significant impediment to the development of effective therapies against this disease. Synovial fluid represents a potential source of disease-specific small non-coding RNAs (sncRNAs) that could aid in the understanding of the pathogenesis of osteoarthritis. We hypothesised that early stages of osteoarthritis would alter the expression of sncRNAs, facilitating the understanding of the underlying pathogenesis and potentially provide early biomarkers.

METHODS

Small RNA sequencing was performed using synovial fluid from the metacarpophalangeal joints of both control and early osteoarthritic horses. A group of differentially expressed sncRNAs was selected for further validation through qRT-PCR using an independent cohort of synovial fluid samples from control and early osteoarthritic horses. Bioinformatic analysis was performed in order to identify putative targets of the differentially expressed microRNAs and to explore potential associations with specific biological processes.

RESULTS

Results revealed 22 differentially expressed sncRNAs including 13 microRNAs; miR-10a, miR-223, let7a, miR-99a, miR-23b, miR-378, miR-143 (and six novel microRNAs), four small nuclear RNAs; U2, U5, U11, U12, three small nucleolar RNAs; U13, snoR38, snord96, and one small cajal body-specific RNA; scarna3. Five sncRNAs were validated; miR-223 was significantly reduced in early osteoarthritis and miR-23b, let-7a-2, snord96A and snord13 were significantly upregulated. Significant cellular actions deduced by the differentially expressed microRNAs included apoptosis (P < 0.0003), necrosis (P < 0.0009), autophagy (P < 0.0007) and inflammation (P < 0.00001). A conservatively filtered list of 57 messenger RNA targets was obtained; the top biological processes associated were regulation of cell population proliferation (P < 0.000001), cellular response to chemical stimulus (P < 0.000001) and cell surface receptor signalling pathway (P < 0.000001).

CONCLUSIONS

Synovial fluid sncRNAs may be used as molecular biomarkers for early disease in equine osteoarthritic joints. The biological processes they regulate may play an important role in understanding early osteoarthritis pathogenesis. Characterising these dynamic molecular changes could provide novel insights on the process and mechanism of early osteoarthritis development and is critical for the development of new therapeutic approaches.

Recent Approaches for Angiogenesis in Search of Successful Tissue Engineering and Regeneration

Angiogenesis plays a central role in human physiology from reproduction and fetal development to wound healing and tissue repair/regeneration. Clinically relevant therapies are needed for promoting angiogenesis in order to supply oxygen and nutrients after transplantation, thus relieving the symptoms of ischemia. Increase in angiogenesis can lead to the restoration of damaged tissues, thereby leading the way for successful tissue regeneration. Tissue regeneration is a broad field that has shown the convergence of various interdisciplinary fields, wherein living cells in conjugation with biomaterials have been tried and tested on to the human body. Although there is a prevalence of various approaches that hypothesize enhanced tissue regeneration via angiogenesis, none of them have been successful in gaining clinical relevance. Hence, the current review summarizes the recent cell-based and cell free (exosomes, extracellular vesicles, micro-RNAs) therapies, gene and biomaterial-based approaches that have been used for angiogenesis-mediated tissue regeneration and have been applied in treating disease models like ischemic heart, brain stroke, bone defects and corneal defects. This review also puts forward a concise report of the pre-clinical and clinical studies that have been performed so far; thereby presenting the credible impact of the development of biomaterials and their 3D concepts in the field of tissue engineering and regeneration, which would lead to the probable ways for heralding the successful future of angiogenesis-mediated approaches in the greater perspective of tissue engineering and regenerative medicine.

Antisense oligonucleotide-based therapies for the treatment of osteoarthritis: Opportunities and roadblocks

Osteoarthritis (OA) is a debilitating disease with no approved disease-modifying therapies. Among the challenges for developing treatment is achieving targeted drug delivery to affected joints. This has contributed to the failure of several drug candidates for the treatment of OA. Over the past 20 years, significant advances have been made in antisense oligonucleotide (ASO) technology for achieving targeted delivery to tissues and cells both in vitro and in vivo. Since ASOs are able to bind specific gene regions and regulate protein translation, they are useful for correcting aberrant endogenous mechanisms associated with certain diseases. ASOs can be delivered locally through intra-articular injection, and can enter cells through natural cellular uptake mechanisms. Despite this, ASOs have yet to be successfully tested in clinical trials for the treatment of OA. Recent chemical modification to ASOs have further improved cellular uptake and reduced toxicity. Among these are locked nucleic acid (LNA)-based ASOs, which have shown promising results in clinical trials for diseases such as hepatitis and dyslipidemia. Recently, LNA-based ASOs have been tested both in vitro and in vivo for their therapeutic potential in OA, and some have shown promising joint-protective effects in preclinical OA animal models. In order to accelerate the testing of ASO therapies in a clinical trial setting for OA, further investigation into delivery mechanisms is required. In this review article, we discuss opportunities for viral-, particle-, biomaterial-, and chemical modification-based therapies, which are currently in preclinical testing. We also address potential roadblocks in the clinical translation of ASO-based therapies for the treatment of OA, such as the limitations associated with OA animal models and the challenges with drug toxicity. Taken together, we review what is known and what would be useful to accelerate translation of ASO-based therapies for the treatment of OA.

The Therapeutic Potential and Role of miRNA, lncRNA, and circRNA in Osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a disease characterized by progressive degeneration, joint hyperplasia, narrowing of joint spaces, and extracellular matrix metabolism. Recent studies have shown that the pathogenesis of OA may be related to non-coding RNA, and its pathological mechanism may be an effective way to reduce OA.

OBJECTIVE

The purpose of this review was to investigate the recent progress of miRNA, long noncoding RNA (lncRNA) and circular RNA (circRNA) in gene therapy of OA, discussing the effects of this RNA on gene expression, inflammatory reaction, apoptosis and extracellular matrix in OA.

METHODS

The following electronic databases were searched, including PubMed, EMBASE, Web of Science, and the Cochrane Library, for published studies involving the miRNA, lncRNA, and circRNA in OA. The outcomes included the gene expression, inflammatory reaction, apoptosis, and extracellular matrix.

RESULTS AND DISCUSSION

With the development of technology, miRNA, lncRNA, and circRNA have been found in many diseases. More importantly, recent studies have found that RNA interacts with RNA-binding proteins to regulate gene transcription and protein translation, and is involved in various pathological processes of OA, thus becoming a potential therapy for OA.

CONCLUSION

In this paper, we briefly introduced the role of miRNA, lncRNA, and circRNA in the occurrence and development of OA and as a new target for gene therapy.

Andrographolide mitigates cartilage damage via miR-27-3p-modulated matrix metalloproteinase13 repression

BACKGROUND

As a potential anti-arthritic agent, Andrographolide (And) is capable of promoting chondrocyte proliferation and preventing apoptosis in pathologic condition. The present study aimed to explore the roles of And in in vivo and in vitro models of osteoarthritis (OA), as well as its underlying molecular mechanisms.

METHODS

An OA mouse model was established using anterior cruciate ligament transection operation on the left knee joint. The pathological changes of articular cartilage were assessed using safranin O staining. Chondrocyte proliferation and apoptosis were measured using cell a counting kit-8 assay and flow cytometry. Bioinformatics algorithms and a luciferase reporter assay were used to evaluate matrix metalloproteinase13 (MMP13) as a direct target of miR-27-3p.

RESULTS

And had the ability to prevent catabolism and facilitate anabolism of articular cartilage in an experimental OA model in mice. In addition, And alleviated chondrocyte apoptosis in in vitro and in vivo models of OA. We also found that both up-regulation of MMP13 and down-regulation of miR-27-3p in the proximal tibia of OA mice and interleukin (IL)-1β-stimulated chondrocytes were reversed by And administration simultaneously. MMP13 was validated as direct target of miR-27-3p and could be suppressed by overexpression of miR-27-3p in mouse chondrocyte. Furthermore, overexpression of miR-27-3p or MMP13 loss-of-function in chondrocytes could alleviate IL-1β-induced apoptosis.

CONCLUSIONS

These results indicated that miR-27-3p/MMP13 signaling axis might be a potential therapeutic target of And for preventing the progression of OA.

miR-142-5p as a CXCR4-Targeted MicroRNA Attenuates SDF-1-Induced Chondrocyte Apoptosis and Cartilage Degradation via Inactivating MAPK Signaling Pathway

Osteoarthritis (OA) is a chronic joint function disorder with characteristics of chondrocytes reduction and extracellular matrix (ECM) components destruction. MicroRNAs (miRNAs) and the SDF-1/CXCR4 axis are essential factors of chondrocyte apoptosis and ECM degeneration. However, very few studies have investigated the correlation between miRNAs and the SDF-1/CXCR4 axis in osteoarthritis so far. Here, through miRNAs microarray and bioinformatics analyses, we identified miR-142-5p as a CXCR4-targeted and dramatically downregulated miRNA in cartilage from OA patients, as well as in SDF-1-induced OA chondrocytes in vitro. In SDF-1-treated primary human OA chondrocytes that were transfected with a miR-142-5p mimic or inhibitor, the expression of CXCR4 was found to be inversely correlated with the expression of miR-142-5p. The dual luciferase reporter assay further verified the target relationship between miR-142-5p and CXCR4. Overexpression of miR-142-5p alleviated OA pathology by suppressing chondrocyte apoptosis, even in CXCR4 overexpressed OA chondrocytes. This was associated with decreased cartilage matrix degradation, reduced cartilage inflammation, and inactivated MAPK signaling pathway. Our study suggests that upregulated expression of CXCR4-targeted miR-142-5p can inhibit apoptosis, inflammation, and matrix catabolism and inactivate the MAPK signaling pathway in OA chondrocytes. Our work provides important insight into targeting miR-142-5p and the SDF-1/CXCR4 axis in OA therapy.

miR-149-5p mitigates tumor necrosis factor-α-induced chondrocyte apoptosis by inhibiting TRADD

Introduction

Chondrocyte apoptosis as a prominent characteristic is usually accompanied by cartilage degeneration in osteoarthritis (OA). Herein, we aimed to determine the roles of miR-149-5p in tumor necrosis factor-α (TNF-α)-induced chondrocyte apoptosis.

Material and methods

Human chondrocytes were cultured with TNF-α to establish an apoptosis cell model in vitro. After transfection with miR-149-5p mimics or co-expression with TRADD in chondrocytes, cell viability, apoptosis, inflammatory cytokines, mRNA and protein expression were measured using CCK8, Annexin V-FITC double staining, ELISA assays, RT-qPCR and western blotting, respectively.

Results

TNF-α-induced chondrocyte apoptosis occurred in association with the inhibition of cell proliferation, the elevation of inflammatory cytokine levels and the activation of TRADD and caspase-3/8 signaling. The post-transcriptional regulatory mechanism suggested that TRADD was a direct target of miR-149-5p, and overexpression of miR-149-5p resulted in the down-regulation of TRADD protein expression in chondrocytes. In addition, miR-149-5p mimics had the ability to attenuate TNF-α-induced inflammation and apoptosis, while transfection with TRADD vector neutralized the protective effects of miR-149-5p on TNF-α-induced chondrocyte dysfunction.

Conclusions

miR-149-5p inversely regulated TNF-α-mediated chondrocyte damage by inhibiting TRADD-modulated caspases signaling. The miR-149-5p/TRADD signaling pathway might be a promising therapeutic target for the treatment of OA.

NEAT1/miR-193a-3p/SOX5 axis regulates cartilage matrix degradation in human osteoarthritis

Long non-coding RNAs (lncRNAs) were reported to be involved in the progression of osteoarthritis (OA). The aim of this work was to explore the functional role of lncRNA nuclear-enriched abundant transcript 1 (NEAT1) in OA. Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was employed to analyze the expression of microRNA (miR-193a)-3p, NEAT1, and sex-determining region Y-box protein 5 (SOX5), as well as the levels of pro-inflammatory cytokines interleukin-6 (IL-6), IL-1β, tumor necrosis factor-α (TNF-α), and IL-8 in OA cartilage tissue and chondrocytes. In addition, flow cytometry was used to measure the apoptosis of chondrocytes. The protein levels of extracellular matrix ACAN, collagen type II α1 chain (Col2a1), matrix metalloproteinase-3 (MMP-3), MMP-13, a disintegrin, and metalloproteinase with thrombospondin motifs (ADAMTS)-5 and SOX5 were determined using western blot analysis. Dual-luciferase reporter assay was performed to determine the target relationship among NEAT1, miR-193a-3p, and SOX5. We found that miR-193a-3p expression was downregulated, while NEAT1 and SOX5 were upregulated in OA cartilage tissue and chondrocytes. Both upregulation of miR-193a-3p and knockdown of NEAT1 suppressed inflammation, apoptosis, and reduced the protein levels of MMP-3, MMP-13, and ADAMTS-5, while elevating ACAN and Col2a1 expression in chondrocytes. NEAT1 targeted miR-193a-3p, and SOX5 was targeted by miR-193a-3p. Silencing of miR-193a-3p reversed the NEAT1 knockdown-mediated effect on the inflammation, apoptosis, and production of the extracellular matrix. The introduction of SOX5 abolished the impact of the upregulation of miR-193a-3p on inflammation, apoptosis, and production of extracellular matrix in chondrocytes. In conclusion, NEAT1/miR-193a-3p/SOX5 axis regulates cartilage matrix degradation in human OA.

Long noncoding RNA SNHG7 contributes to cell proliferation, migration, invasion and epithelial to mesenchymal transition in non-small cell lung cancer by regulating miR-449a/TGIF2 axis

Background

Non‐small cell lung cancer (NSCLC) is an intractable malignant lung cancer with high rates of metastasis and mortality. Currently, long noncoding RNA nuclear RNA host gene 7 (SNHG7) is recognized as a biomarker of multiple cancers. However, the role of SNHG7 in NSCLC requires further understanding.

Methods

The expression of SNHG7, miR‐449a and TGIF2 in NSCLC tumors and cells was examined by quantitative real time polymerase chain reaction (qRT‐PCR). Cell viability was measured by MTT assay. Cell migration and invasion was conducted using transwell assay. Protein expression of TGIF2, vimentin, N‐cadherin and E‐cadherin was detected by western blot. The interaction between miR‐449a and SNHG7 or TGIF2 was determined by luciferase reporter system, RIP and RNA pull‐down assay, respectively. Xenograft mice models were established by subcutaneously injecting A549 cells transfected with sh‐SNHG7 and sh‐control.

Results

SNHG7 expression was upregulated in NSCLC tumors and cells compared with normal tissues and cells. SNHG7 silencing repressed cell proliferation, migration, invasion and epithelial to mesenchymal transition (EMT) in NSCLC. Consistently, SNHG7 knockdown hindered tumor growth in vivo. The subsequent luciferase reporter system, RIP and RNA pull‐down assay validated the interaction between miR‐449a and SNHG7 or TGIF2. The rescue experiments displayed that miR‐449a inhibitor counteracted SNHG7 silencing induced inhibition on proliferation, migration, invasion and EMT. Similarly, restoration of TGIF2 reversed miR‐449a mediated inhibition on cell progression. In addition, the results indicated that SNHG7 could regulate cell progression by targeting miR‐449a/TGIF2 axis.

Conclusion

SNHG7 contributed to cell proliferation, migration, invasion and EMT in NSCLC by upregulating TGIF2 via sponging miR‐449a, representing a novel targeted therapy method for NSCLC.

Downregulation of microRNA-16-5p accelerates fracture healing by promoting proliferation and inhibiting apoptosis of osteoblasts in patients with traumatic brain injury

Patients who suffered a traumatic brain injury (TBI) show a faster fracture healing than patients with isolated fractures. Prior studies have suggested that this process may be accelerated through the inhibition of key microRNAs. In this study, we aimed to explore the mechanisms underlying this phenomenon, with a special focus on miR-16-5p, which is markedly decreased in patients with TBI. In vitro, miR-16-5p over-expression significantly inhibited cell proliferation in MC3T3-E1 cells transfected with agomiR-16-5p. Flow cytometry analysis further demonstrated that the overexpression of miR-16-5p induced cell cycle G1/S phase arrest and apoptosis. Moreover, target prediction and luciferase reporter assay demonstrated that miR-16-5p could negatively regulate Bcl-2 and Cyclin-D1 expression. Meanwhile, Bcl-2 and Cyclin-D1 were up-regulated after osteogenic differentiation while the down-regulation of endogenous Bcl-2 and Cyclin-D suppressed the osteogenic differentiation of MC3T3-E1 cells. In vivo, PBS, agomiR-16-5p and antagomiR-16-5p were injected into fracture sites to assess any improvements in fracture healing, which further confirmed the negative effect of miR-16-5p on fracture healing. Together, these results demonstrate miR-16-5p downregulation may accelerate fracture healing by enhancing the proliferation and inhibiting the apoptosis of osteoblasts in patients with both fractures and TBI. These phenomena may be exploited in the treatment of fractures.

The exosome-like vesicles from osteoarthritic chondrocyte enhanced mature IL-1β production of macrophages and aggravated synovitis in osteoarthritis

Synovitis, a common clinical symptom for osteoarthritis (OA) patients, is highly related to OA pathological progression and pain manifestation. The activated synovial macrophages have been demonstrated to play an important role in synovitis, but the mechanisms about macrophage activation are still not clear. In this study, we found that the exosome-like vesicles from osteoarthritic chondrocytes could be a new biological factor to stimulate inflammasome activation and increase mature IL-1β production in macrophages. The degraded cartilage explants produced more exosome-like vesicles than the nondegraded ones, while the exosome-like vesicles from chondrocytes could enter into joint synovium tissue and macrophages. Moreover, the exosome-like vesicles from osteoarthritic chondrocytes enhanced the production of mature IL-1β in macrophages. These vesicles could inhibit ATG4B expression via miR-449a-5p, leading to inhibition of autophagy in LPS-primed macrophages. The decreased autophagy promoted the production of mitoROS, which further enhanced the inflammasome activation and subsequent IL-1β processing. Ultimately, the increase of mature IL-1β may aggravate synovial inflammation and promote the progression of OA disease. Our study provides a new perspective to understand the activation of synovial macrophages and synovitis in OA patients, which may be beneficial for therapeutic intervention in synovitis-related OA patients.

αB-crystallin (CRYAB) regulates the proliferation, apoptosis, synthesis and degradation of extracellular matrix of chondrocytes in osteoarthritis

Osteoarthritis (OA) is a chronic joint disease and hard to cure at present. Alpha B-crystallin (CRYAB) has been identified as a downregulated gene in OA cartilage. However, the precise roles and underlying molecular mechanisms of CRYAB in OA progression have not been elucidated. In the present study, we found that the expression of CRYAB in cartilages from patients with OA was significantly lower than that in the cartilages from patients with no prior medical history of OA. We established mouse models with OA by destabilization of the medial meniscus (DMM) surgery and found that the expression of CRYAB in OA cartilage was lower than that in the normal cartilages, too. Moreover, we demonstrated that the expression of CRYAB was increased during chondrogenic differentiation and cartilage development. Functional assays revealed that overexpression of CRYAB promoted the proliferation of chondrocytes and inhibited apoptosis, while knockdown of CRYAB presented opposite results. In addition, overexpression of CRYAB upregulated the expression of anabolic markers, Col2a1 and ACAN, and reduced the expression of catabolic markers, MMP13 and ADAMTS5. Conversely, knockdown of CRYAB blocked the expression of the anabolic markers and increased the expression of catabolic markers. Collectively, the results suggest that CRYAB promoted the proliferation and extracellular matrix production of chondrocytes, and inhibited chondrocytes apoptosis and cartilage degradation simultaneously. Thus, CRYAB might be a potential therapeutic target for OA treatment.

miRNA-26a-5p Accelerates Healing via Downregulation of PTEN in Fracture Patients with Traumatic Brain Injury

Patients who sustain a traumatic brain injury (TBI) are known to have a significantly quicker fracture healing time than patients with isolated fractures, but the underlying mechanism has yet to be identified. In this study, we found that the upregulation of miRNA-26a-5p induced by TBI correlated with a decrease in phosphatase and tensin homolog (PTEN) in callus formation. In vitro, overexpressing miRNA-26a-5p inhibited PTEN expression and accelerated osteoblast differentiation, whereas silencing of miRNA-26a-5p inhibited osteoblast activity. Reduction of PTEN facilitated osteoblast differentiation via the PI3K/AKT signaling pathway. Through luciferase assays, we found evidence that PTEN is a miRNA-26a-5p target gene that negatively regulates the differentiation of osteoblasts. Moreover, the present study confirmed that preinjection of agomiR-26a-5p leads to increased bone formation. Collectively, these results indicate that miRNA-26a-5p overexpression may be a key factor governing the improved fracture healing observed in TBI patients after the downregulation of PTEN and PI3K/AKT signaling. Upregulation of miRNA-26a-5p may therefore be a promising therapeutic strategy for promoting fracture healing.

The role of sirtuin 1 and its activator, resveratrol in osteoarthritis

Osteoarthitis (OA) is the most common aging-related joint pathology; the aging process results in changes to joint tissues that ultimately contribute to the development of OA. Articular chondrocytes exhibit an aging-related decline in their proliferative and synthetic capacity. Sirtuin 1 (SIRT 1), a longevity gene related to many diseases associated with aging, is a nicotinamide adenine dinucleotide (NAD⁺)-dependent protein deacetylase and master metabolic regulator. Along with its natural activator resveratrol, SIRT 1 actively participates in the OA pathological progress. SIRT 1 expression in osteoarthritic cartilage decreases in the disease progression of OA; it appears to play a predominantly regulatory role in OA. SIRT 1 can regulate the expression of extracellular matrix (ECM)-related proteins; promote mesenchymal stem cell differentiation; play anti-catabolic, anti-inflammatory, anti-oxidative stress, and anti-apoptosis roles; participate in the autophagic process; and regulate bone homeostasis in OA. Resveratrol can activate SIRT 1 in order to inhibit OA disease progression. In the future, activating SIRT 1 via resveratrol with improved bioavailability may be an appropriate therapeutic approach for OA.