The regulatory effects of proteoglycans on collagen fibrillogenesis and morphology investigated using biomimetic proteoglycans

wnt10a is required for zebrafish median fin fold maintenance and adult unpaired fin metamorphosis

BACKGROUND

Mutations of human WNT10A are associated with odonto-ectodermal dysplasia syndromes. Here, we present analyses of wnt10a loss-of-function mutants in the zebrafish.

RESULTS

wnt10a mutant zebrafish embryos display impaired tooth development and a collapsing median fin fold (MFF). Rescue experiments show that wnt10a is essential for MFF maintenance both during embryogenesis and later metamorphosis. The MFF collapse could not be attributed to increased cell death or altered proliferation rates of MFF cell types. Rather, wnt10a mutants show reduced expression levels of dlx2a in distal-most MFF cells, followed by compromised expression of col1a1a and other extracellular matrix proteins encoding genes. Transmission electron microscopy analysis shows that although dermal MFF compartments of wnt10a mutants initially are of normal morphology, with regular collagenous actinotrichia, positioning of actinotrichia within the cleft of distal MFF cells becomes compromised, coinciding with actinotrichia shrinkage and MFF collapse.

CONCLUSIONS

MFF collapse of wnt10a mutant zebrafish is likely caused by the loss of distal properties in the developing MFF, strikingly similar to the proposed molecular pathomechanisms underlying the teeth defects caused by the loss of Wnt10 in fish and mammals. In addition, it points to thus fur unknown mechanisms controlling the linear growth and stability of actinotrichia and their collagen fibrils.

MassArray Genotyping as a Selection Tool for Extending the Shelf-Life of Fresh Gilthead Sea Bream and European Seabass

In modern aquaculture, genomics-driven breeding programs have emerged as powerful tools for optimizing fish quality. This study focused on two emblematic Mediterranean fish species, the European seabass (Dicentrarchus labrax) and the gilthead sea bream (Sparus aurata), with a primary aim of exploring the genetic basis of white muscle/fillet degradation in fresh fish following harvest. We identified 57 and 44 missense SNPs in gilthead sea bream and European seabass, respectively, located within genes encoding for endogenous proteases responsible for fillet quality. These SNPs were cherry-picked based on their strategic location within the catalytic/regulatory domains of endogenous proteases that are expressed in the white muscle. Using MassArray technology, we successfully associated differentiated enzymatic activity of those endogenous proteases post-harvest as a phenotypic trait with genetic polymorphism of six SNPs in gilthead sea bream and nine in European seabass. These findings can be valuable attributes in selective breeding programs toward the extension of freshness and shelf life of these species. The integration of MassArray technology into breeding programs offers a cost-effective strategy for harnessing the potential of these genetic variants to enhance the overall quality of the final product. Recognizing that fresh fish perishability is a challenge, extending shelf-life is pivotal in reducing losses and production costs.

Emerging Role of Non-collagenous Bone Proteins as Osteokines in Extraosseous Tissues

Bone is a unique tissue, composed of various types of cells embedded in a calcified extracellular matrix (ECM), whose dynamic structure consists of organic and inorganic compounds produced by bone cells. The main inorganic component is represented by hydroxyapatite, whilst the organic ECM is primarily made up of type I collagen and non-collagenous proteins. These proteins play an important role in bone homeostasis, calcium regulation, and maintenance of the hematopoietic niche. Recent advances in bone biology have highlighted the importance of specific bone proteins, named "osteokines", possessing endocrine functions and exerting effects on nonosseous tissues. Accordingly, osteokines have been found to act as growth factors, cell receptors, and adhesion molecules, thus modifying the view of bone from a static tissue fulfilling mobility to an endocrine organ itself. Since bone is involved in a paracrine and endocrine cross-talk with other tissues, a better understanding of bone secretome and the systemic roles of osteokines is expected to provide benefits in multiple topics: such as identification of novel biomarkers and the development of new therapeutic strategies. The present review discusses in detail the known osseous and extraosseous effects of these proteins and the possible respective clinical and therapeutic significance.

Utilizing intramammary Melaleuca alternifolia as an organic internal sealant for dry-off therapy in Murrah buffaloes

The effects of intramammary dry cow therapy based on the administration of 5% Melaleuca alternifolia tea tree essential oil (TTO) as an internal teat sealant to Murrah cows were evaluated. A longitudinal prospective and retrospective negative control study was performed using 12 buffaloes from a total of 20 Murrah buffaloes on an organic farm, with the cow used as a control for herself. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for treatments with pure oil (TTO) and medication containing 5% TTO (O5) were determined. The buffaloes were clinically examined, and the teats were evaluated using thermography and ultrasound. Udder health was monitored during the first 100 days in milk (DIM) using milk somatic cell count (SCC) and California mastitis test (CMT). Laboratory tests against standard strains Staphylococcus aureus ATCC®25,923™, Escherichia coli ATCC®25,922™, and wild bacterial strains showed maximum MIC values of 50 µL/mL for the TTO and O5 treatments. One wild-type S. aureus strain showed no MBC. No adverse effects were observed after the intramammary application of TTO. The CMT and SCC values were similar (P > 0.05) for all observations. The medication containing 5% TTO was effective in vitro and compatible with the intramammary tissue in vivo of Murrah buffaloes. TTO was safe, not inducing inflammatory processes or other modifications of the teat detectable by thermography or ultrasound. It was able to protect buffaloes during the dry period under field conditions, demonstrating potential use as a teat sealant for organic farms.

Design strategies for composite matrix and multifunctional polymeric scaffolds with enhanced bioactivity for bone tissue engineering

Over the past few decades, various bioactive material-based scaffolds were investigated and researchers across the globe are actively involved in establishing a potential state-of-the-art for bone tissue engineering applications, wherein several disciplines like clinical medicine, materials science, and biotechnology are involved. The present review article's main aim is to focus on repairing and restoring bone tissue defects by enhancing the bioactivity of fabricated bone tissue scaffolds and providing a suitable microenvironment for the bone cells to fasten the healing process. It deals with the various surface modification strategies and smart composite materials development that are involved in the treatment of bone tissue defects. Orthopaedic researchers and clinicians constantly focus on developing strategies that can naturally imitate not only the bone tissue architecture but also its functional properties to modulate cellular behaviour to facilitate bridging, callus formation and osteogenesis at critical bone defects. This review summarizes the currently available polymeric composite matrices and the methods to improve their bioactivity for bone tissue regeneration effectively.

Proteoglycans and proteoglycan mimetics for tissue engineering

Proteoglycans play a crucial role in proper tissue morphology and function throughout the body that is defined by a combination of their core protein and the attached glycosaminoglycan chains. Although they serve a myriad of roles, the functions of extracellular proteoglycans can be generally sorted into four categories: modulation of tissue mechanical properties, regulation and protection of the extracellular matrix, sequestering of proteins, and regulation of cell signaling. The loss of proteoglycans can result in significant tissue disfunction, ranging from poor mechanical properties to uncontrolled inflammation. Because of the key roles they play in proper tissue function and due to their complex synthesis, the past two decades have seen significant research into the development of proteoglycan mimetic molecules to recapitulate the function of proteoglycans for therapeutic and tissue engineering applications. These strategies have ranged from semisynthetic graft copolymers to recombinant proteoglycan domains synthesized by genetically engineered cells. In this review, we highlight some of the important functions of extracellular proteoglycans, as well as the strategies developed to recapitulate these functions.

Recent advancements in decellularized matrix technology for bone tissue engineering

The native extracellular matrix (ECM) provides a matrix to hold tissue/organ, defines the cellular fate and function, and retains growth factors. Such a matrix is considered as a most biomimetic scaffold for tissue engineering due to the biochemical and biological components, 3D hierarchical structure, and physicomechanical properties. Several attempts have been performed to decellularize allo- or xeno-graft tissues and used them for bone repairing and regeneration. Decellularized ECM (dECM) technology has been developed to create an in vivo-like microenvironment to promote cell adhesion, growth, and differentiation for tissue repair and regeneration. Decellularization is mediated through physical, chemical, and enzymatic methods. In this review, we describe the recent progress in bone decellularization and their applications as a scaffold, hydrogel, bioink, or particles in bone tissue engineering. Furthermore, we address the native dECM limitations and the potential of non-bone dECM, cell-based ECM, and engineered ECM (eECM) for in vitro osteogenic differentiation and in vivo bone regeneration.

Acmella oleracea extract increases collagen content and organization in partially transected tendons

Acmella oleracea contains spilanthol as the main active compound, which possesses analgesic and anti-inflammatory effects that can favor tendon reorganization. To analyze the effect of A. oleracea on the content and organization of collagen in injured tendons, the calcaneal tendon of male Lewis rats was partially transected and treated at the site of injury with a topical application of 20% A. oleracea ointment (AO group) or with the ointment base without the plant extract (B group). The animals were euthanized 21 days after partial transection. Higher collagen concentration was observed in the AO group than in the B group, and morphological analysis using polarization microscopy showed higher birefringence in the AO group than in the B group, indicating higher collagen organization. No difference was observed in the number of fibroblasts, blood vessels, proteoglycan distribution, and maximum load between the B and AO groups. In conclusion, topical application of 20% A. oleracea ointment increased the molecular organization and content of collagen, thus indicating a potential application in tendon repair. Studies on the later phases of the tendon healing process are necessary to demonstrate the possible biomechanical changes after the application of A. oleracea ointment.

Zinn's zonule

The Zonule of Zinn, or ciliary zonule, is the elaborate system of extracellular fibers that centers the lens in the eye. In humans, the fibers transmit forces that flatten the lens during the process of disaccommodation, thereby bringing distant objects into focus. Zonular fibers are composed almost entirely of 10-12 nm-wide microfibrils, of which polymerized fibrillin is the most abundant component. The thickest fibers have a fascicular organization, where hundreds or thousands of microfibrils are gathered into micrometer-wide bundles. Many such bundles are aggregated to form a fiber. Dozens of proteins comprise the zonule. Most are derived from cells of the non-pigmented ciliary epithelium in the pars plana region, although some are probably contributed by the lens and perhaps other tissues of the anterior segment. Zonular fibers are viscoelastic cables but their component microfibrils are rather stiff structures. Thus, the elastic properties of the fibers likely stem from lateral interactions between microfibrils. Rupture of zonular fibers and subsequent lens dislocation (ectopia lentis) can result from blunt force trauma or be a sequela of other eye diseases, notably exfoliation syndrome. Ectopia lentis is also a feature of syndromic conditions caused typically by mutations in microfibril-associated genes. The resulting ocular phenotypes raise the possibility that the zonule regulates lens size and shape, globe size, and even corneal topology, in addition to its well-recognized role in accommodation.

A Role for Monosaccharides in Nucleation Inhibition and Transport of Collagen

Background: Collagenous tissues are composed of precisely oriented, tightly packed collagen fibril bundles to confer the maximal strength within the smallest volume. While this compact form benefits mobility, it consequentially restricts vascularity and cell density to a minimally viable level in some regions. These tissues reside in a homeostatic state with an unstable equilibrium, where perturbations to structure or molecular milieu cause descension into a long-term compromised state. Several studies have shown that glycosaminoglycans are key molecules required for healthy tissue maintenance. Our long-term goal is to determine if glycosaminoglycans serve a critical function of stabilizing soluble monomeric collagen in the interstitial fluid that bathes tissue for immediate availability in tissue development and repair in vivo. Materials and Methods: To test glycosaminoglycan and collagen interactions at the most fundamental level, we have explored the effect of the monosaccharides that populate the glycosaminoglycans of the extracellular matrix on collagen assembly kinetics, pre-established matrix stability, and collagen incorporation into a preassembled matrix. Results: Results showed that monosaccharides increased the threshold concentration required for spontaneous polymerization by at least three orders of magnitude. When the monosaccharides were introduced to a pre-existing collagen network, fibrillar dissociation was undetectable. Fluorescent-labeling studies illustrated that in the presence of the saccharide solution, soluble collagen maintains the functional capacity to integrate into a pre-existing network. Conclusion: This work demonstrates a feasible role for glycosaminoglycans in supporting tissue remodeling and highlights the potential importance of age-related deterioration of glycosaminoglycan biosynthesis in reference to the homeostasis of collagen-based tissues.

The Bone Extracellular Matrix in Bone Formation and Regeneration

Bone regeneration repairs bone tissue lost due to trauma, fractures, and tumors, or absent due to congenital disorders. The extracellular matrix (ECM) is an intricate dynamic bio-environment with precisely regulated mechanical and biochemical properties. In bone, ECMs are involved in regulating cell adhesion, proliferation, and responses to growth factors, differentiation, and ultimately, the functional characteristics of the mature bone. Bone ECM can induce the production of new bone by osteoblast-lineage cells, such as MSCs, osteoblasts, and osteocytes and the absorption of bone by osteoclasts. With the rapid development of bone regenerative medicine, the osteoinductive, osteoconductive, and osteogenic potential of ECM-based scaffolds has attracted increasing attention. ECM-based scaffolds for bone tissue engineering can be divided into two types, that is, ECM-modified biomaterial scaffold and decellularized ECM scaffold. Tissue engineering strategies that utilize the functional ECM are superior at guiding the formation of specific tissues at the implantation site. In this review, we provide an overview of the function of various types of bone ECMs in bone tissue and their regulation roles in the behaviors of osteoblast-lineage cells and osteoclasts. We also summarize the application of bone ECM in bone repair and regeneration. A better understanding of the role of bone ECM in guiding cellular behavior and tissue function is essential for its future applications in bone repair and regenerative medicine.

Teat characteristics in relation to animal temperament during milking in buffaloes, and comparison of buffalo and cow teat morphology

This study aimed to examine the teat characteristics in relation to the animal temperament during milking in the Anatolian buffaloes using ultrasonographic, histomorphological and immunohistochemical methods. The teat canal length (TCL), teat wall thickness (TWT), teat cisternal diameter (TCD), teat diameter (TD), teat length (TL), and teat circumference (TC) values in docile (n = 5) and nervous (n = 7) buffaloes were measured at the 0th, 3rd and 6th minute of stimulation. In additional experiments, comparative histomorphology and immunohistochemical examinations of buffalo (n = 7) and cow teats (n = 8) were performed. It was determined that post-stimulation mean TCL values were significantly higher in nervous buffaloes than those of teats in docile buffaloes (p < .05). A significant positive correlation between TCD and TD, TL and TC in both docile and nervous buffaloes was noted (p < .05). Unlike nervous buffaloes where only 3/14 teat canals were open by 3rd minute of milking stimulation, almost all (9/10) teat canals were observed opened in docile buffaloes. There were fewer muscle but more collagen bundles in buffalo teats compared with cow teats. It seems that temperament of animal during milking effects the milking efficiency, and in nervous buffaloes, probably the stimulation alone may not be sufficient for opening of the teat canal and hence achieve complete milking.