What is the selection process for osteoarthritis pharmacotherapy?

Engineering of MSC-Derived Exosomes: A Promising Cell-Free Therapy for Osteoarthritis

Osteoarthritis (OA) is characterized by progressive cartilage degeneration with increasing prevalence and unsatisfactory treatment efficacy. Exosomes derived from mesenchymal stem cells play an important role in alleviating OA by promoting cartilage regeneration, inhibiting synovial inflammation and mediating subchondral bone remodeling without the risk of immune rejection and tumorigenesis. However, low yield, weak activity, inefficient targeting ability and unpredictable side effects of natural exosomes have limited their clinical application. At present, various approaches have been applied in exosome engineering to regulate their production and function, such as pretreatment of parental cells, drug loading, genetic engineering and surface modification. Biomaterials have also been proved to facilitate efficient delivery of exosomes and enhance treatment effectiveness. Here, we summarize the current understanding of the biogenesis, isolation and characterization of natural exosomes, and focus on the large-scale production and preparation of engineered exosomes, as well as their therapeutic potential in OA, thus providing novel insights into exploring advanced MSC-derived exosome-based cell-free therapy for the treatment of OA.

Cardiovascular Drugs and Osteoarthritis: Effects of Targeting Ion Channels

Osteoarthritis (OA) and cardiovascular diseases (CVD) share many similar features, including similar risk factors and molecular mechanisms. A great number of cardiovascular drugs act via different ion channels and change ion balance, thus modulating cell metabolism, osmotic responses, turnover of cartilage extracellular matrix and inflammation. These drugs are consumed by patients with CVD for many years; however, information about their effects on the joint tissues has not been fully clarified. Nevertheless, it is becoming increasingly likely that different cardiovascular drugs may have an impact on articular tissues in OA. Here, we discuss the potential effects of direct and indirect ion channel modulating drugs, including inhibitors of voltage gated calcium and sodium channels, hyperpolarization-activated cyclic nucleotide-gated channels, β-adrenoreceptor inhibitors and angiotensin-aldosterone system affecting drugs. The aim of this review was to summarize the information about activities of cardiovascular drugs on cartilage and subchondral bone and to discuss their possible consequences on the progression of OA, focusing on the modulation of ion channels in chondrocytes and other joint cells, pain control and regulation of inflammation. The implication of cardiovascular drug consumption in aetiopathogenesis of OA should be considered when prescribing ion channel modulators, particularly in long-term therapy protocols.

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.

CircADAMTS6/miR-431-5p axis regulate interleukin-1β induced chondrocyte apoptosis

BACKGROUND

Growing evidence suggests that circular RNAs (circRNAs) are involved in the development of osteoarthritis (OA). The present study aimed to explore the CircADAMTS6/miR-431-5p axis with respect to regulating interleukin-1β (IL-1β) induced chondrocyte apoptosis.

METHODS

We first evaluated the differentially expressed circRNAs between normal chondrocytes and interleukin (IL)-1β-stimulated chondrocytes. Then, bioinformatic analysis was performed to identify the role and function of circADAMTS6. Small interfering RNA-expressing or overexpressing circADAMTS6 lentiviral vectors were used for transduction of chondrocytes. Annexin-V-fluorescein isothiocyanate (FITC) double staining was performed to measure the apoptotic rate of the chondrocytes in each group. Finally, a dual luciferase reporter assay was performed to identify the target relationship between circADAMTS6 and miR-431-5p.

RESULTS

After treatment with IL-1β, circADAMTS6 was down-regulated compared to the normal chondrocyte group. The overexpression of circADAMTS6 inhibited apoptosis in human chondrocytes, as indicated by annexin-V-FITC double staining. However, overexpression of miR-431-5p had the opposite effect. A dual luciferase reporter assay indicated that circADAMTS6 could directly binding with miR-431-5p.

CONCLUSIONS

Our findings demonstrate that the circADAMTS6/miR-431-5p axis comprises a new target for OA. Bioinformatic analysis suggested that circADAMTS6 acted as a sponge of miR-431-5p.