Potential of zebrafish as a model to characterise MicroRNA profiles in mechanically mediated joint degeneration

Characterization of a chemically induced osteoarthritis model in zebrafish

Osteoarthritis (OA) is characterized by the progressive degeneration of the synovial joint, leading to irreversible damage to articular cartilage and subchondral bone. While animal models have advanced our understanding of OA, numerous unresolved issues still remain. The zebrafish, known for its transparent body, rapid developmental, and impressive regenerative capabilities, offers substantial potential for osteoarthritis research. This study seeks to establish a new OA model utilizing the zebrafish jaw joint, acting as a supplement to traditional animal models. In the future, this model could serve as a valuable platform for delving deeper into the mechanisms of this disease, as well as for advancing drug discovery and therapeutic interventions. Leveraging the skeletal structure of zebrafish, we targeted the largest jaw joint for our research. A custom fixation device was crafted, and a microinjection system was utilized to inject mono-iodoacetate (MIA) or collagenase type II (CTII) into the joint cavity of zebrafish. Subsequent analyses included histological staining, immunohistochemistry, OA research society international (OARSI) scoring, and real-time in vivo imaging were performed at 7, 14, and 28 days post injection. Our results effectively demonstrated the presence of synovial inflammation and cartilage damage within the zebrafish mandible, affirming the feasibility of inducing OA in zebrafish. In conclusion, the local injection of chemical agents into the joint cavity of zebrafish effectively induced the occurrence of OA. Establishing the zebrafish OA model enhances the array of animal models available for OA research. Moreover, zebrafish present distinct advantages, including robust regenerative abilities, genetic editing simplicity, and efficient drug screening. Consequently, this offers a fresh avenue for investigating the pathogenesis, prevention, and potential therapeutic approaches for human OA.

Mechanical stress can regulate temporomandibular joint cavitation via signalling pathways

The temporomandibular joint (TMJ), composed of temporal fossa, mandibular condyle and a fibrocartilage disc with upper and lower cavities, is the biggest synovial joint and biomechanical hinge of the craniomaxillofacial musculoskeletal system. The initial events that give rise to TMJ cavities across diverse species are not fully understood. Most studies focus on the pivotal role of molecules such as Indian hedgehog (Ihh) and hyaluronic acid (HA) in TMJ cavitation. Although biologists have observed that mechanical stress plays an irreplaceable role in the development of biological tissues and organs, few studies have been concerned with how mechanical stress regulates TMJ cavitation. Based on the evidence from human or other animal embryos today, it is implicated that mechanical stress plays an essential role in TMJ cavitation. In this review, we discuss the relationship between mechanical stress and TMJ cavitation from evo-devo perspectives and review the clinical features and potential pathogenesis of TMJ dysplasia.

A comprehensive coding and microRNA transcriptome of vertebral bone in postlarvae and juveniles of Senegalese sole (Solea senegalensis)

Understanding vertebral bone development is essential to prevent skeletal malformations in farmed fish related to genetic and environmental factors. This is an important issue in Solea senegalensis, with special impact of spinal anomalies in postlarval and juvenile stages. Vertebral bone transcriptomics in farmed fish mainly comes from coding genes, and barely on miRNA expression. Here, we used RNA-seq of spinal samples to obtain the first comprehensive coding and miRNA transcriptomic repertoire for postlarval and juvenile vertebral bone, covering different vertebral phenotypes and egg-incubation temperatures related to skeleton health in S. senegalensis. Coding genes, miRNA and pathways regulating bone development and growth were identified. Differential transcriptomic profiles and suggestive mRNA-miRNA interactions were found between postlarvae and juveniles. Bone-related genes and functions were associated with the extracellular matrix, development and regulatory processes, calcium binding, retinol and lipid metabolism or response to stimulus, including those revealed by the miRNA targets related to signaling, cellular and metabolic processes, growth, cell proliferation and biological adhesion. Pathway enrichment associated with fish skeleton were identified when comparing postlarvae and juveniles: growth and bone development functions in postlarvae, while actin cytoskeleton, focal adhesion and proteasome related to bone remodeling in juveniles. The transcriptome data disclosed candidate coding and miRNA gene markers related to bone cell processes, references for functional studies of the anosteocytic bone of S. senegalensis. This study establishes a broad transcriptomic foundation to study healthy and anomalous spines under early thermal conditions across life-stages in S. senegalensis, and for comparative analysis of skeleton homeostasis and pathology in fish and vertebrates.

Modulation of miR-146b Expression during Aging and the Impact of Physical Activity on Its Expression and Chondrogenic Progenitors

The finding of molecules associated with aging is important for the prevention of chronic degenerative diseases and for longevity strategies. MicroRNAs (miRNAs) are post-transcriptional regulators involved in many biological processes and miR-146b-5p has been shown to be involved in different degenerative diseases. However, miR-146b-5p modulation has not been evaluated in mesenchymal stem cells (MSCs) commitment or during aging. Therefore, the modulation of miR-146b-5p in the commitment and differentiation of mesenchymal cells as well as during maturation and aging in zebrafish model were analyzed. In addition, circulating miR-146b-5p was evaluated in human subjects at different age ranges. Thus, the role of physical activity in the modulation of miR-146b-5p was also investigated. To achieve these aims, RT (real-time)-PCR, Western blot, cell transfections, and three-dimensional (3D) culture techniques were applied. Our findings show that miR-146b-5p expression drives MSCs to adipogenic differentiation and increases during zebrafish maturation and aging. In addition, miR-146b-5p expression is higher in females compared to males and it is associated with the aging in humans. Interestingly, we also observed that the physical activity of walking downregulates circulating miR-146b-5p levels in human females and increases the number of chondroprogenitors. In conclusion, miR-146b-5p can be considered an age-related marker and can represent a useful marker for identifying strategies, such as physical activity, aimed at counteracting the degenerative processes of aging.

New trends for osteoarthritis: Biomaterials, models and modeling

The burden of osteoarthritis (OA), one of the major causes of functional disabilities in humans and animals, continues to increase worldwide while no disease-modifying OA drugs (DMOADs) that either slow down or reverse disease progression have been made available. Here, we provide a brief overview of recent advances in: designing new OA drug delivery approaches, focusing on lubrication-based biomaterials and drug delivery systems, such as hydrogels, liposomes, dendrimers, micro- and nanoparticles; using either large (horse) or small (zebrafish) relevant animal models to evaluate new therapeutic strategies; and OA in vitro modeling, focusing on 3D (organoid) models of cartilage regarding the Replace, Reduce and Refine (3R) principle of animal experimentation.