Glycosaminoglycans in Tissue Engineering: A Review

"Biological evaluation of 3D-Printed chitosan-based scaffolds for tissue engineering"

Chitosan is a natural polysaccharide with excellent biocompatibility, biodegradability, and antibacterial capabilities, making it a good candidate for tissue engineering. 3D printing has revolutionized biomaterial fabrication owing to its precision, customization, and ability to create complex structures. This article aims to provide an overview of the current advances in 3D printing techniques for fabricating scaffolds based on chitosan and its derivatives. It also describes various printing methods, including extrusion bioprinting technique, inkjet bioprinting, stereolithography, digital light processing, and indirect 3D printing for controlling porosity, mechanical strength, and biological characteristics of chitosan scaffolds for a variety of tissues, like bone, vascular, cardiac, cartilage, and skin. This review also examines the biological properties of 3D-printed chitosan scaffolds. The advancements in biological performance and 3D printing technology indicate a promising future for developing flexible, customized scaffolds consisting of chitosan.

Meta-analysis of in vitro methods on tracheal decellularization

INTRODUCTION

Tracheal decellularization is one of the main processes to provide tracheal substitutes for tracheal replacement. Recently, studies have been held for agents and combinations of processes for tracheal decellularization with different outcomes. This study aimed to evaluate the efficacy of tracheal decellularization by the immunogenic cellular elements using residual deoxyribonucleic acid (DNA) contents (ng/mg) and the preservation of biomechanical integrity by glycosaminoglycan (GAG) content (μg/mg), modulus tensile strength (MPa), ultimate tensile strength (MPa), and stress loading of 50% deformation (N).

METHODS

We conducted a meta-analysis based on PRISMA criteria. Data from experimental studies in MEDLINE, Scopus, and ScienceDirect from inception to August 21, 2023, were sought and computed using RevMan 5.4. The outcomes of tracheal decellularization were evaluated through effect size estimates based on pooled Standardized Mean Difference (SMD) with 95% CI.

RESULTS

Tracheal decellularization has significantly reduced the DNA and GAG content after the process (SMD: -11.77, 95% CI [-13.92, -8.62], p < 0.00001; SMD: -6.70, 95% CI [-9.55, -3.85], p < 0.00001). No significant outcomes were observed in modulus and ultimate tensile strength result (SMD: -0.14, 95% CI [-0.64, 0.36], p = 0.58; SMD: 0.11, 95% CI [-0.57, 0.80], p = 0.75). The stress loading of 50% deformation was observed to significantly lower (SMD: -1.61, 95% CI [-2.49, -0.72], p = 0.0004).

CONCLUSION

Tracheal decellularization has been proven to effectively remove immunogenic cells. However, extracellular matrix integrity and biomechanical properties vary among different decellularization techniques, indicating a need for further refinement to achieve better preservation.

Adipose-Derived Stem Cell Specific Affinity Peptide-Modified Adipose Decellularized Scaffolds for Promoting Adipogenesis

Adipose-derived stem cells (ADSCs) are known to promote angiogenesis and adipogenesis. However, their limited ability to efficiently target and integrate into specific tissues poses a major challenge for ADSC-based therapies. In this study, we identified a seven-amino acid peptide sequence (P7) with high specificity for ADSCs using phage display technology. P7 was then covalently conjugated to decellularized adipose-derived matrix (DAM), creating an "ADSC homing device" designed to recruit ADSCs both in vitro and in vivo. The P7-conjugated DAM significantly enhanced ADSC adhesion and proliferation in vitro. After being implanted into rat subcutaneous tissue, immunofluorescence staining after 14 days revealed that P7-conjugated DAM recruited a greater number of ADSCs, promoting angiogenesis and adipogenesis in the surrounding tissue. Moreover, CD206 immunostaining at 14 days indicated that P7-conjugated DAM facilitated the polarization of macrophages to the M2 phenotype at the implantation site. These findings demonstrate that the P7 peptide has a high affinity for ADSCs, and its conjugation with DAM significantly improves ADSC recruitment in vivo. This approach holds great potential for a wide range of applications in material surface modification.

Vitreous Fibrillar Structure and Interfibrillar Composition in Adult Mice

Purpose

Although mice are widely used models for human eye diseases, knowledge of their vitreous is scarce and fragmentary. This study characterizes the structure and composition of vitreous fibrils and their interfibrillar space. Given the role of this fibrillar network in maintaining the vitreous' biomechanical properties, the impact of intravitreal injections on vitreous architecture was also explored.

Methods

Healthy adult C57/BL6J mice were studied. Classical histological techniques, picrosirius red-polarization, immunofluorescence, lectin histochemistry, and hyaluronic acid binding protein assays were used to examine vitreous fibrils and interfibrillar space. For the analysis of distribution of components along the fibrils, the Airyscan microscopy was used to achieve higher resolution.

Results

Vitreous fibrils consist of fibrillar collagen, glycoproteins (fibrillin 1, fibronectin, laminin, and collagen IV), N-acetyl galactosamine, and hyaluronan, all absent in the interfibrillar space. A single sterile intravitreal saline injection induced an inflammatory insult, characterized by increased fibril density and macrophage/hyalocyte invasion. Lysosome-associated membrane protein 1 (Lamp1) immunohistochemistry suggests these cells may remove fibrils via phagocytosis and activate a remodeling process in the vitreous.

Conclusions

This study enhances understanding of the mouse vitreous structure, suggesting fibrils are composed of glycoprotein-wrapped collagen cores. Furthermore, the absence of hyaluronan and glycoproteins between fibrils may explain lower viscosity in mice compared with humans. Intravitreal injections as an inflammatory insult disrupt fibril networks and activate macrophages/hyalocytes.

The Effect of Alginate/Hyaluronic Acid Proportion on Semi-Interpenetrating Hydrogel Properties for Articular Cartilage Tissue Engineering

One of the emergent regenerative treatments for the restoration of the articular cartilage is tissue engineering (TE), in which hydrogels can functionally imitate the extracellular matrix (ECM) of the native tissue and create an optimal microenvironment for the restoration of the defective tissue. Hyaluronic acid (HA) is known for its potential in the field of TE as a regenerative material for many tissues. It is one of the major components of the articular cartilage ECM contributing to cell proliferation and migration. HA is the only non-sulphated glycosaminoglycan (GAG). However, herein, we use a HA presenting a high amount of sulphated glycosaminoglycans (sGAGs), altering the intrinsic properties of the material particularly in terms of biological response. Alginate (Alg) is another polysaccharide widely used in TE that allows stiff and stable hydrogels to be obtained when crosslinked with CaCl2. Taking the benefit of the favourable characteristics of each biomaterial, semi-interpenetrating (semi-IPN) hydrogels had been developed by the combination of both materials, in which alginate is gelled, and HA remains uncrosslinked within the hydrogel. Varying the concentration of alginate and HA, the final rheological, viscoelastic, and mechanical properties of the hydrogel can be tailored, always seeking a trade-off between biological and physico-mechanical properties. All developed semi-IPN hydrogels have great potential for biomedical applications.

Transcriptome analysis to explore the molecular mechanisms involved in the dormancy-arousal process in Pomacea canaliculata (Lamarck, 1819)

The apple snail, Pomacea canaliculata (Lamarck, 1819), a freshwater snail listed as a pernicious invasive alien species by the World Conservation Union (IUCN), has caused serious agricultural and ecological harm worldwide. This species has inflicted significant agricultural and ecological damage on a global scale. Under conditions of extreme environmental stress, the apple snail enters a state of dormancy and remains in this dormant phase until environmental conditions become favorable again, which serves as a crucial survival strategy. In our study, we subjected apple snails to 30 days of air-exposure stress followed by rehydration to reactivate them. Our objective was to elucidate the underlying mechanisms associated with drought tolerance, dormancy, and subsequent arousal based on transcriptomic analyses. The results indicated that the groups subjected to 5-, 15- and 30-day air-exposure stress treatments (DRY05, DRY15 and DRY30) exhibited a general down-regulation of metabolism-related pathways. These pathways included starch and sucrose metabolism, linoleic acid metabolism, glutathione metabolism and glycosaminoglycan degradation, compared with the control (CK). In addition, the weighted correlation network analysis (WGCNA) identified two critical pathways: toll-like receptor signaling pathway and adherens junction. The down-regulation of these pathways indicated a decrease in immune levels during dormancy in apple snails. This may further lead to the inhibition of apoptosis and a reduction in energy expenditure, thereby sustaining vital activities. The up-regulation of intercellular adhesion and immune-related pathways upon reawakening (RCY01) further substantiates the presence of this tolerance mechanism during dormancy in the apple snail. This study provides a reference for understanding the tolerance of apple snails to extreme environments, and provides a basic theory for apple snail biocontrol research.

Nanochitin From Crab Shells: Production, Chemical Modification, Composite Materials, and Physiological Functions

Large quantities of crab shells are generated in food-processing plants. In this review, the authors summarize a series of research findings on the production of nanochitin, its physical properties, chemical modifications, and functions, which have not been fully addressed in existing literature. Nanochitin, which has a width of 10 nm, is derived from chitin, the main component of crab shells, using a technology similar to that used to produce nanocellulose from wood. Unlike conventional chitin, nanochitin is well dispersed in water, making it easy to mold and process into various products for different applications. They can also be modified for specific uses through processes such as acylation and etherification to enhance their physical properties and add functionality. Nanochitin, which are known for their exceptional mechanical strength, can be blended with resins to create composite films with improved strength and elasticity. These films maintain the transparency of the resin, reduce its thermal expansion, and offer reinforcement. Chitin and its derivative chitosan are used as wound dressings, hemostatic agents, and health foods. Nanochitin and its deacetyl derivatives have diverse functions such as topical medicine for the skin, ingestion as a health food, and use as pesticides or fertilizers for plants.

Rapid characterization of polysaccharides from marine animals using chemical degradation combined with liquid chromatography mass spectrometry

Glycosaminoglycans of marine origin have exceptional biological activities, but rapid elucidation strategies for precise structures are still lacking. In this study, the optimal conditions for deacetylation of glycosaminoglycans were optimized first. The hydrazinolysis time of 24 h was determined as the final condition, oligosaccharides with a degree of polymerization of 2-14 are mainly produced after hydrazinolysis. Then mixed oligosaccharides generated by deacetylation-deamination cleavage of polysaccharides were detected with hydrophilic interaction chromatography with tandem mass spectrometry (HILIC-MS/MS), and the total ion chromatography showed excellent resolution. The mass spectrometry data were automatically processed by GlycReSoft, and the corresponding matching results were obtained according to the set parameters. A small amount of keratan sulfate exists in oligosaccharides of Teuthida and Salmo salar, and ion peaks corresponding to IdoA-GalNAc4S exist in oligosaccharides of Scophthalmus maximus and Salmo salar. The results of the manual analysis of the mass spectrometry data verified that the HILIC-MS/MS combined with automatic analysis by software adopted in this study could achieve accurate matching and matching of mixed oligosaccharide components. The establishment of a rapid and accurate analysis strategy for the structure of glycosaminoglycans in this study will help the development of its application and standardized industrial production.

Mechanistic studies of chondroitin sulfate/dermatan sulfate isolated from freshwater fish discards on osteogenesis in MC3T3-E1 cells

Glycosaminoglycans (GAGs) are essential bone extracellular matrix molecules that regulate osteoblast differentiation. Numerous studies have explored endogenous and exogenous GAG osteoanabolic activities using appropriate in vitro and in vivo models. However, GAGs' underlying the mechanism of action and structure-function relationships need to be elucidated in detail. Earlier, we showed that exogenous GAG can bring about osteogenesis in pre-osteoblast cells. In the present study, we have elucidated the mechanism of action of exogenous GAGs, especially of the chondroitin sulfate/dermatan sulfate (CS/DS) class on osteogenesis. GAGs were immobilized, and osteoblast differentiation was evaluated in MC3T3-E1 cells. Results indicated that GAGs supported osteoblast differentiation by promoting collagen production, extracellular matrix formation, and subsequent mineralization. We elucidated the mechanisms underlying these effects by assessing the key signaling molecules involved in osteogenesis in response to exogenous CS/DS with/without BMP2. CS/DS alone significantly increased pERK1/2 and ATF4 expression levels differentially in a time-dependent manner without significant effects on BMP2, RUNX2, and pSMAD5 protein expression. On the other hand, CS/DS, in the presence of BMP2, differentially increased BMP2, pSMAD5, pERK1/2, RUNX2, and ATF4 expression levels at various time points. Collectively, these results strongly suggest that CS/DS can promote osteogenesis, and in the presence of BMP2, it could promote SMAD-mediated ERK-dependent osteogenesis.

Unveiling the therapeutic journey of snail mucus in diabetic wound care

A diabetic wound (DW) is an alteration in the highly orchestrated physiological sequence of wound healing especially, the inflammatory phase. These alterations result in the generation of oxidative stress and inflammation at the injury site. This further leads to the impairment in the angiogenesis, extracellular matrix, collagen deposition, and re-epithelialization. Additionally, in DW there is the presence of microbial load which makes the wound worse and impedes the wound healing cycle. There are several treatment strategies which have been employed by the researchers to mitigate the aforementioned challenges. However, they failed to address the multifactorial pathogenic nature of the disease. Looking at the severity of the disease researchers have explored snail mucus and its components such as achacin, allantoin, elastin, collagen, and glycosaminoglycan due to its multiple therapeutic potentials; however, glycosaminoglycan (GAGs) is very important among all because they accelerate the wound-healing process by promoting reepithelialization, vascularization, granulation, and angiogenesis at the site of injury. Despite its varied applications, the field of snail mucus in wound healing is still underexplored. The present review aims to highlight the role of snail mucus in diabetic wound healing, the advantages of snail mucus over conventional treatments, the therapeutic potential of snail mucus, and the application of snail mucus in DW. Additionally, clinical trials, patents, structural variations, and advancements in snail mucus characterization have been covered in the article.

Immunomodulation Effects of Porcine Cartilage Acellularized Matrix (pCAM) for Osteoarthritis Treatment

BACKGROUND

Pain reduction, immunomodulation, and cartilage repair are key therapeutic goals in osteoarthritis (OA) treatment. In this study, we evaluated the therapeutic effects of porcine cartilage acellularized matrix (pCAM) derived from naive tissue and compared it with the synthetic material polynucleotides (PN) for OA treatment.

METHODS

pCAM was produced from porcine cartilage through physicochemical processing. LC-MS protein profiling identified the key proteins. In vitro experiments involved treating human synovial cell with pCAM and PN to assess cell viability and reductions in pro-inflammatory cytokines (IL-1β and IL-6). In vivo studies utilized a rat DMM-induced OA model. Pain was evaluated in weight-bearing tests, and inflammation reduction was confirmed using specific macrophage markers of CD68, CD86, and CD163 in immunohistochemical staining of synovial tissue. Cartilage regeneration was evaluated by histopathological analyses.

RESULTS

The major protein components of pCAM include factors integral to cartilage and ECM integrity. They also contain proteins that help reduce inflammation. In vitro studies revealed a decrease in pro-inflammatory cytokines and survival of synovial cells were observed. In vivo treatment with pCAM resulted in a reduction of pain and inflammation, while promoting cartilage regeneration, thereby accelerating the healing process in OA.

CONCLUSION

Our findings suggest that pCAM may contribute to the treatment of OA by alleviating synovial inflammation and supporting cartilage regeneration, thereby addressing both the inflammatory and degenerative aspects of the disease.

Carbohydrates and neurotrophic factors: A promising partnership for spinal cord injury rehabilitation

Spinal cord injury (SCI) leaves a temporary or enduring motor, sensory, and autonomic function loss, significantly impacting the patient's quality of life. Given their biocompatibility, bioactivity, and tunable attributes, three-dimensional scaffolds frequently employ carbohydrates to facilitate spinal cord regeneration. These scaffolds have also been engineered to be novel local delivery platforms that present distinct advantages in the targeted transportation of drug candidates to the damaged spinal cord, ensuring the right dosage and duration of administration. Neurotrophic factors have emerged as promising therapeutic candidates, preserved neuron survival and encouraged severed axons repair, although their local and continuous delivery is believed to produce considerable spinal cord rehabilitation. This study aims to discuss breakthroughs in scaffold engineering, exploiting carbohydrates as an essential part of their structure, and highlight their impact on spinal cord regeneration and sustained neurotrophic factors delivery to treat SCI.

Enhancement of the Cytokine Adsorption Capacity of Octacalcium Phosphate by Interaction-Controlled Glycosaminoglycan Modification to Promote Osteoblastic Differentiation

This study was designed to investigate how the strength of the interaction between octacalcium phosphate (OCP) and modified chondroitin-A sulfate (CS-A), a glycosaminoglycan, regulates the adsorption-desorption of cytokines and subsequently affects the osteoblastic differentiation of mesenchymal stem cells (MSCs) in vitro. The utilization of cytokines produced by cells, such as macrophages, stimulated by the hydrolysis of OCP, is expected to enhance the bone regeneration capacity of the OCP. CS-Na was used to modify CS-A on the OCP immobilized with the amino group through electrostatic interactions. On the other hand, N-hydroxysuccinimide (NHS)-esterified CS-A was used to form the covalent bond between CS-A and the amino group on the surface of OCP. X-ray diffraction and Raman spectroscopy indicated that the CS-A-modified OCP maintained its structure, regardless of the modification process. The remaining ratio of the modified CS-A in the buffer suggests that increasing the immobilized density of the amino group and the modification using NHS ester may enhance interaction strength between OCP and CS-A. The adsorption amount and retention rate of recombinant human bone morphological protein-2 (rhBMP-2, an endogenous cytokine model) increased onto CS-A-modified OCP under physiological conditions when the interaction strength between OCP and the protein was stronger. The higher interaction strength between the OCP and CS-A could be associated with the enhanced adsorption affinity for the lower-molecular-weight basic protein. The alkaline phosphatase activity of MSCs increased depending on the remaining rate of rhBMP-2 adsorption on the CS-A-modified-OCP. Fourier transform infrared spectroscopy and chemical analysis indicated that the hydrolysis of the OCP progressed regardless of CS-A modification after MSC incubation. The present study suggests that stronger interactions between the OCP and glycosaminoglycans could contribute to the capture and retention of endogenous cytokines on the surface to further promote osteoblastic differentiation under the chemical environment induced by the hydrolysis of the OCP.

Validation of a Simple HPLC/UV Method for Assay and In Vitro Release of Glycosaminoglycan from Pharmaceutical Formulations

This study encompasses the validation of a simple, rapid, and sensitive HPLC/UV method developed in accordance with the guidelines set by ICH Q2(R2) for obtaining the active pharmaceutical ingredient from the glycosaminoglycan family in topical formulations. Previous methods reported for analyzing glycosaminoglycans in semisolid formulations are relatively complex and time-consuming, involving extraction, purification, and derivatization. This developed analytical method allows for straightforward extraction of the active pharmaceutical ingredient from the matrix, enabling the direct injection of samples. This method was performed and validated for the assay of the pharmaceutical gel and cream formulations to investigate the parameters of linearity (r = 0.9997 for the gel formulation and r = 0.9993 for the cream formulation), precision, accuracy, specificity, and robustness by HPLC/UV. Additionally, this method was used to determine the active ingredient in in vitro release studies. In vitro similarity correlation against commercial products was performed according to the Mann-Whitney U statistical test. The similarity results were 96.5-102.7% for the gel formulation and 98.0-106.0% for the cream formulation, which remained within the limits (75-133.33%) according to USP 1724. This proved that in vitro release profiles for both formulations were like those of the commercial product. In light of the research findings, we believe that the HPLC/UV analysis presented can be further enhanced in the future for determining the levels of active ingredients in various pharmaceutical formulations or for monitoring the levels of glycosaminoglycans in biological matrixes.

Development and characterization of a novel injectable thyroid extracellular matrix hydrogel for enhanced thyroid tissue engineering applications

Hypothyroidism, a condition characterized by decreased synthesis and secretion of thyroid hormones, significantly impacts intellectual development and physical growth. Current treatments, including hormone replacement therapy and thyroid transplantation, have limitations due to issues like hormone dosage control and immune rejection. Tissue engineering presents a potential solution by combining cells and biomaterials to construct engineered thyroid tissue. This study focuses on the development and characterization of a novel 3D injectable hydrogel derived from thyroid extracellular matrix (TEM) for thyroid tissue engineering. TEM hydrogels were prepared through decellularization of rat thyroid tissue, followed by extensive physicochemical and mechanical property evaluations. The TEM hydrogels exhibited properties similar to natural thyroid tissue, including high biocompatibility and a complex 3D ultrastructure. Thyroid hormone-secreting cells cultured in TEM hydrogels demonstrated superior viability, hormone secretion, and thyroid-related gene expression compared to those in traditional type I collagen hydrogels. The study also confirmed the significant retention of key growth factors and ECM proteins within the TEM hydrogels. The results indicate that TEM hydrogels can provide a biomimetic microenvironment, promoting the long-term survival and function of thyroid cells, thus holding great promise for the treatment of hypothyroidism. This research contributes a potential new avenue for thyroid tissue engineering, offering a promising alternative for hypothyroidism treatment.

Hydrogel-Enhanced Autologous Chondrocyte Implantation for Cartilage Regeneration-An Update on Preclinical Studies

Autologous chondrocyte implantation (ACI) and matrix-induced ACI (MACI) have demonstrated improved clinical outcomes and reduced revision rates for treating osteochondral and chondral defects. However, their ability to achieve lasting, fully functional repair remains limited. To overcome these challenges, scaffold-enhanced ACI, particularly utilizing hydrogel-based biomaterials, has emerged as an innovative strategy. These biomaterials are intended to mimic the biological composition, structural organization, and biomechanical properties of native articular cartilage. This review aims to provide comprehensive and up-to-date information on advancements in hydrogel-enhanced ACI from the past decade. We begin with a brief introduction to cartilage biology, mechanisms of cartilage injury, and the evolution of surgical techniques, particularly looking at ACI. Subsequently, we review the diversity of hydrogel scaffolds currently undergoing development and evaluation in preclinical studies for articular cartilage regeneration, emphasizing chondrocyte-laden hydrogels applicable to ACI. Finally, we address the key challenges impeding effective clinical translation, with particular attention to issues surrounding fixation and integration, aiming to inform and guide the future progression of tissue engineering strategies.

Inflammation-Modulating Biomedical Interventions for Diabetic Wound Healing: An Overview of Preclinical and Clinical Studies

A diabetic wound exemplifies the challenge of chronic, nonhealing wounds. Elevated blood sugar levels in diabetes profoundly disrupt macrophage function, impairing crucial activities such as phagocytosis, immune response, cell migration, and blood vessel formation, all essential for effective wound healing. Moreover, the persistent presence of pro-inflammatory cytokines and reactive oxygen species, coupled with a decrease in anti-inflammatory factors, exacerbates the delay in wound healing associated with diabetes. This review emphasizes the dysfunctional inflammatory responses underlying diabetic wounds and explores preclinical studies of inflammation-modulating bioactives and biomaterials that show promise in expediting diabetic wound healing. Additionally, this review provides an overview of selected clinical studies employing biomaterials and bioactive molecules, shedding light on the gap between extensive preclinical research and limited clinical studies in this field.

Polysaccharide-based chondroitin sulfate macromolecule loaded hydrogel/scaffolds in wound healing- A comprehensive review on possibilities, research gaps, and safety assessment

Wound healing is an intricate multifactorial process that may alter the extent of scarring left by the wound. A substantial portion of the global population is impacted by non-healing wounds, imposing significant financial burdens on the healthcare system. The conventional dosage forms fail to improve the condition, especially in the presence of other morbidities. Thus, there is a pressing requirement for a type of wound dressing that can safeguard the wound site and facilitate skin regeneration, ultimately expediting the healing process. In this context, Chondroitin sulfate (CS), a sulfated glycosaminoglycan material, is capable of hydrating tissues and further promoting the healing. Thus, this comprehensive review article delves into the recent advancement of CS-based hydrogel/scaffolds for wound healing management. The article initially summarizes the various physicochemical characteristics and sources of CS, followed by a brief understanding of the importance of hydrogel and CS in tissue regeneration processes. This is the first instance of such a comprehensive summarization of CS-based hydrogel/scaffolds in wound healing, focusing more on the mechanistic wound healing process, furnishing the recent innovations and toxicity profile. This contemporary review provides a profound acquaintance of strategies for contemporary challenges and future direction in CS-based hydrogel/scaffolds for wound healing.

M proteins of group A Streptococcus bind hyaluronic acid via arginine-arginine/serine-arginine motifs

Tissue injury, including extracellular matrix (ECM) degradation, is a hallmark of group A Streptococcus (GAS) skin infection and is partially mediated by M proteins which possess lectin-like properties. Hyaluronic acid is a glycosaminoglycan enriched in the cutaneous ECM, yet an interaction with M proteins has yet to be explored. This study revealed that hyaluronic acid binding was conserved across phylogenetically diverse M proteins, mediated by RR/SR motifs predominantly localized in the C repeat region. Keratinocyte wound healing was decreased through the recruitment of hyaluronic acid by M proteins in an M type-specific manner. GAS strains 5448 (M1 serotype) and ALAB49 (M53 serotype) also bound hyaluronic acid via M proteins, but hyaluronic acid could increase bacterial adherence independently of M proteins. The identification of host-pathogen mechanisms that affect ECM composition and cell repair responses may facilitate the development of nonantibiotic therapeutics that arrest GAS disease progression in the skin.

Unraveling the intricacies of glycosaminoglycan biosynthesis: Decoding the molecular symphony in understanding complex polysaccharide assembly

Glycosaminoglycans (GAGs) are extensively utilized in clinical, cosmetic, and healthcare field, as well as in the treatment of thrombosis, osteoarthritis, rheumatism, and cancer. The biological production of GAGs is a strategy that has garnered significant attention due to its numerous advantages over traditional preparation methods. In this review, we embark on a journey to decode the intricate molecular symphony that orchestrates the biosynthesis of glycosaminoglycans. By unraveling the complex interplay of related enzymes and thorough excavation of the intricate metabolic cascades involved, GAGs chain aggregation and transportation, which efficiently and controllably modulate GAGs sulfation patterns involved in biosynthetic pathway, we endeavor to offer a thorough comprehension of how these remarkable GAGs are intricately assembled and pushes the boundaries of our understanding in GAGs biosynthesis.

Human Serum, Following Absorption of Fish Cartilage Hydrolysate, Promotes Dermal Fibroblast Healing through Anti-Inflammatory and Immunomodulatory Proteins

Background/Objectives: Marine collagen peptides (MCPs) and glycosaminoglycans (GAGs) have been described as potential wound-healing (WH) agents. Fish cartilage hydrolysate (FCH) is a natural active food ingredient obtained from enzymatic hydrolysis which combines MCPs and GAGs. Recently, the clinical benefits of FCH supplementation for the skin, as well as its mode of action, have been demonstrated. Some of the highlighted mechanisms are common to the WH process. The aim of the study is therefore to investigate the influence of FCH supplementation on the skin healing processes and the underlying mechanisms. Methods: To this end, an ex vivo clinical approach, which takes into account the clinical digestive course of nutrients, coupled with primary cell culture on human dermal fibroblasts (HDFs) and ultra-deep proteomic analysis, was performed. The effects of human serum enriched in circulating metabolites resulting from FCH ingestion (FCH-enriched serum) were assessed on HDF WH via an in vitro scratch wound assay and on the HDF proteome via diaPASEF (Data Independent Acquisition-Parallel Accumulation Serial Fragmentation) proteomic analysis. Results: Results showed that FCH-enriched human serum accelerated wound closure. In support, proteins with anti-inflammatory and immunomodulatory properties and proteins prone to promote hydration and ECM stability showed increased expression in HDFs after exposure to FCH-enriched serum. Conclusions: Taken together, these data provide valuable new insights into the mechanisms that may contribute to FCH's beneficial impact on human skin functionality by supporting WH. Further studies are needed to reinforce these preliminary data and investigate the anti-inflammatory and immunomodulatory properties of FCH.

Delivery of Nitric Oxide by Chondroitin Sulfate C Increases the Rate of Wound Healing through Immune Modulation

Chronic wounds impact 2.5% of the United States population and will continue to be a major clinical challenge due to increases in population age, chronic disease diagnoses, and antibiotic-resistant infection. Nitric oxide (NO) is an endogenous signaling molecule that represents an attractive, simple therapeutic for chronic wound treatment due to its innate antibacterial and immunomodulatory function. Unfortunately, modulating inflammation for extended periods by low levels of NO is not possible with NO gas. Herein, we report the utility of a NO-releasing glycosaminoglycan biopolymer (GAG) for promoting wound healing. GAGs are naturally occurring biopolymers that are immunomodulatory and known to be involved in the native wound healing process. Thus, the combination of NO and GAG biopolymers represents an attractive wound therapeutic due to these known independent roles. The influence and contribution of chondroitin sulfate C (CSC) modified to facilitate controlled and targeted delivery of NO (CSC-HEDA/NO) was evaluated using in vitro cell proliferation and migration assays and an in vivo wound model.

Injectable Tissue Adhesive Microgel Composite Containing Antifibrotic Drug for Vocal Fold Scarring

Vocal fold (VF) scarring, a complex problem in laryngology, results from injury and inflammation of the layered architecture of the VFs. The resultant voice hoarseness, for which successful therapeutic options are currently limited, affects the patient's quality of life. A promising strategy to reverse this disorder is the use of antifibrotic drugs. The present study proposes a novel microbead-embedded injectable hydrogel that can sustain the release of the anti-fibrotic drug pirfenidone (PFD) for vocal fold scarring. Microbeads were developed using sodium alginate and gelatin, which were further embedded into a biomimetic and tissue adhesive gellan gum (GG) hydrogel. The microbead-embedded hydrogel exhibited improved injectability, viscoelasticity, tissue adhesiveness, degradability, and swelling compared to the hydrogel without beads. Additionally, the bead-embedded hydrogel could sustain the release of the PFD for a week. In vitro studies showed that the drug-loaded hydrogel could reduce the migration and proliferation of fibroblast cells in a dose-dependent manner. In summary, this study demonstrates the potential of a PFD-loaded injectable hydrogel with enhanced viscoelastic and tissue-adhesive properties for vocal fold scarring applications.

A biological guide to glycosaminoglycans: current perspectives and pending questions

Mammalian glycosaminoglycans (GAGs), except hyaluronan (HA), are sulfated polysaccharides that are covalently attached to core proteins to form proteoglycans (PGs). This article summarizes key biological findings for the most widespread GAGs, namely HA, chondroitin sulfate/dermatan sulfate (CS/DS), keratan sulfate (KS), and heparan sulfate (HS). It focuses on the major processes that remain to be deciphered to get a comprehensive view of the mechanisms mediating GAG biological functions. They include the regulation of GAG biosynthesis and postsynthetic modifications in heparin (HP) and HS, the composition, heterogeneity, and function of the tetrasaccharide linkage region and its role in disease, the functional characterization of the new PGs recently identified by glycoproteomics, the selectivity of interactions mediated by GAG chains, the display of GAG chains and PGs at the cell surface and their impact on the availability and activity of soluble ligands, and on their move through the glycocalyx layer to reach their receptors, the human GAG profile in health and disease, the roles of GAGs and particular PGs (syndecans, decorin, and biglycan) involved in cancer, inflammation, and fibrosis, the possible use of GAGs and PGs as disease biomarkers, and the design of inhibitors targeting GAG biosynthetic enzymes and GAG-protein interactions to develop novel therapeutic approaches.

Impact of Composition and Autoclave Sterilization on the Mechanical and Biological Properties of ECM-Mimicking Cryogels

Cryogels represent a valid strategy as scaffolds for tissue engineering. In order to adequately support adhesion and proliferation of anchorage-dependent cells, different polymers need to be combined within the same scaffold trying to mimic the complex features of a natural extracellular matrix (ECM). For this reason, in this work, gelatin (Gel) and chondroitin sulfate (CS), both functionalized with methacrylic groups to produce CSMA and GelMA derivatives, were selected to prepare cryogel networks. Both homopolymer and heteropolymer cryogels were produced, via radical crosslinking reactions carried out at -12 °C for 2 h. All the scaffolds were characterized for their mechanical, swelling and morphological properties, before and after autoclave sterilization. Moreover, they were evaluated for their biocompatibility and ability to support the adhesion of human gingival fibroblasts and tenocytes. GelMA-based homopolymer networks better withstood the autoclave sterilization process, compared to CSMA cryogels. Indeed, GelMA cryogels showed a decrease in stiffness of approximately 30%, whereas CSMA cryogels of approximately 80%. When GelMA and CSMA were blended in the same network, an intermediate outcome was observed. However, the hybrid scaffolds showed a general worsening of the biological performance. Indeed, despite their ability to withstand autoclave sterilization with limited modification of the mechanical and morphological properties, the hybrid cryogels exhibited poor cell adhesion and high LDH leakage. Therefore, not only do network components need to be properly selected, but also their combination and ability to withstand effective sterilization process should be carefully evaluated for the development of efficient scaffolds designed for tissue engineering purposes.

Degradation of specific glycosaminoglycans improves transfection efficiency and vector production in transient lentiviral vector manufacturing processes

Both cell surface and soluble extracellular glycosaminoglycans have been shown to interfere with the exogenous nucleic acid delivery efficiency of non-viral gene delivery, including lipoplex and polyplex-mediated transfection. Most gene therapy viral vectors used commercially and in clinical trials are currently manufactured using transient transfection-based bioprocesses. The growing demand for viral vector products, coupled with a global shortage in production capability, requires improved transfection technologies and processes to maximise process efficiency and productivity. Soluble extracellular glycosaminoglycans were found to accumulate in the conditioned cell culture medium of suspension adapted HEK293T cell cultures, compromising transfection performance and lentiviral vector production. The enzymatic degradation of specific, chondroitin sulphate-based, glycosaminoglycans with chondroitinase ABC was found to significantly enhance transfection performance. Additionally, we report significant improvements in functional lentiviral vector titre when cultivating cells at higher cell densities than those utilised in a control lentiviral vector bioprocess; an improvement that was further enhanced when cultures were supplemented with chondroitinase ABC prior to transfection. A 71.2% increase in functional lentiviral vector titre was calculated when doubling the cell density prior to transfection compared to the existing process and treatment of the high-density cell cultures with 0.1 U/mL chondroitinase ABC resulted in a further 18.6% increase in titre, presenting a method that can effectively enhance transfection performance.

Characterization and Structural Analysis of a Novel Carbohydrate-Binding Module from Family 96 with Chondroitin Sulfate-Specific Binding Capacity

Chondroitin sulfate (CS) is the predominant glycosaminoglycan within the human body and is widely applied in various industries. Carbohydrate-binding modules (CBMs) possessing the capacity for carbohydrate recognition are verified to be important tools for polysaccharide investigation. Only one CS-specific CBM, PhCBM100, has hitherto been characterized. In the present study, two CBM96 domains present in the same putative PL8_3 chondroitin AC lyase were discovered and recombinantly expressed. The results of microtiter plate assays and affinity gel electrophoresis assays showed that the two corresponding proteins, DmCBM96-1 and DmCBM96-2, bind specifically to CSs. The crystal structure of DmCBM96-1 was determined at a 2.20 Å resolution. It adopts a β-sandwich fold comprising two antiparallel β-sheets, showing structural similarities to TM6-N4, which is the founding member of the CBM96 family. Site mutagenesis analysis revealed that the residues of Arg27, Lys45, Tyr51, Arg53, and Arg157 are critical for CS binding. The characterization of the two CBM96 proteins demonstrates the diverse ligand specificity of the CBM96 family and provides promising tools for CS investigation.

Sweet but Challenging: Tackling the Complexity of GAGs with Engineered Tailor-Made Biomaterials

Glycosaminoglycans (GAGs) play a crucial role in tissue homeostasis by regulating the activity and diffusion of bioactive molecules. Incorporating GAGs into biomaterials has emerged as a widely adopted strategy in medical applications, owing to their biocompatibility and ability to control the release of bioactive molecules. Nevertheless, immobilized GAGs on biomaterials can elicit distinct cellular responses compared to their soluble forms, underscoring the need to understand the interactions between GAG and bioactive molecules within engineered functional biomaterials. By controlling critical parameters such as GAG type, density, and sulfation, it becomes possible to precisely delineate GAG functions within a biomaterial context and to better mimic specific tissue properties, enabling tailored design of GAG-based biomaterials for specific medical applications. However, this requires access to pure and well-characterized GAG compounds, which remains challenging. This review focuses on different strategies for producing well-defined GAGs and explores high-throughput approaches employed to investigate GAG-growth factor interactions and to quantify cellular responses on GAG-based biomaterials. These automated methods hold considerable promise for improving the understanding of the diverse functions of GAGs. In perspective, the scientific community is encouraged to adopt a rational approach in designing GAG-based biomaterials, taking into account the in vivo properties of the targeted tissue for medical applications.

Biomimetic biphasic microsphere preparation based on the thermodynamic incompatibility of glycosaminoglycan with gelatin methacrylate for hair regeneration

Hair follicle (HF) tissue engineering is promising for hair loss treatment especially for androgenetic alopecia. Physiologically, the initiation of HF morphogenesis relies on the interactions between hair germ mesenchymal and epithelial layers. To simulate this intricate process, in this study, a co-flowing microfluidic-assisted technology was developed to produce dual aqueous microdroplets capturing growth factors and double-layer cells for subsequent use in hair regeneration. Microspheres, called G/HAD, were generated using glycosaminoglycan-based photo-crosslinkable biological macromolecule (HAD) shells and gelatin methacrylate (GelMA) cores to enclose mesenchymal cells (MSCs) and mouse epidermal cells (EPCs). The findings indicated that the glycosaminoglycan-based HAD shells display thermodynamic incompatibility with GelMA cores, resulting in the aqueous phase separation of G/HAD cell spheres. These G/HAD microspheres exhibited favorable characteristics, including sustained growth factor release and wet adhesion properties. After transplantation into the dorsal skin of BALB/c nude mice, G/HAD cell microspheres efficiently induced the regeneration of HFs. This approach enables the mass production of approximately 250 dual-layer microspheres per minute. Thus, this dual-layer microsphere fabrication method holds great potential in improving current hair regeneration techniques and can also be combined with other tissue engineering techniques for various regenerative purposes.

A chondroitin sulfate purified from shark cartilage and bovine serum albumin interaction activity

Chondroitin sulfate (CS) was extracted and purified from shark cartilage, and its interaction with bovine serum albumin (BSA) were studied. The content of chondroitin sulfate in shark cartilage was 29.97 % using the 1,9-dimethyl-methylene blue method. The molecular weight of CS was determined to be 62.464 kDa by high-performance gel permeation chromatography. UV and FT-IR spectroscopy identified the characteristics of CS and its functional group information. NMR spectroscopy and disaccharide derivatization revealed that CS was predominantly composed of disulfated disaccharides, specifically ΔDi4,6S. Fluorescence quenching experiments indicated that the interaction between CS and BSA exhibited static quenching, with a binding site number of 1. The binding process was primarily mediated by van der Waals forces and hydrogen bonds. Furthermore, synchronous and 3D fluorescence spectroscopy demonstrated that CS had minimal impact on the polarity and hydrophobicity of the microenvironment surrounding Tyr and Trp residues. UV-vis absorption and circular dichroism (CD) spectroscopy demonstrated the altered structure of BSA. The molecular docking analysis revealed that CS formed hydrogen bonds and salt bridges with BSA, predominantly binding to the IIA substructure domain of BSA. Investigating the interaction between CS and BSA holds the potential for enhancing its applications in drug delivery and tissue engineering endeavors.

A Tunable Glycosaminoglycan-Peptide Nanoparticle Platform for the Protection of Therapeutic Peptides

The popularity of Glycosaminoglycans (GAGs) in drug delivery systems has grown as their innate ability to sequester and release charged molecules makes them adept in the controlled release of therapeutics. However, peptide therapeutics have been relegated to synthetic, polymeric systems, despite their high specificity and efficacy as therapeutics because they are rapidly degraded in vivo when not encapsulated. We present a GAG-based nanoparticle system for the easy encapsulation of cationic peptides, which offers control over particle diameter, peptide release behavior, and swelling behavior, as well as protection from proteolytic degradation, using a singular, organic polymer and no covalent linkages. These nanoparticles can encapsulate cargo with a particle diameter range spanning 130-220 nm and can be tuned to release cargo over a pH range of 4.5 to neutral through the modulation of the degree of sulfation and the molecular weight of the GAG. This particle system also confers better in vitro performance than the unencapsulated peptide via protection from enzymatic degradation. This method provides a facile way to protect therapeutic peptides via the inclusion of the presented binding sequence and can likely be expanded to larger, more diverse cargo as well, abrogating the complexity of previously demonstrated systems while offering broader tunability.

Molecular Mechanisms in Pathophysiology of Mucopolysaccharidosis and Prospects for Innovative Therapy

Mucopolysaccharidoses (MPSs) are a group of inborn errors of the metabolism caused by a deficiency in the lysosomal enzymes required to break down molecules called glycosaminoglycans (GAGs). These GAGs accumulate over time in various tissues and disrupt multiple biological systems, including catabolism of other substances, autophagy, and mitochondrial function. These pathological changes ultimately increase oxidative stress and activate innate immunity and inflammation. We have described the pathophysiology of MPS and activated inflammation in this paper, starting with accumulating the primary storage materials, GAGs. At the initial stage of GAG accumulation, affected tissues/cells are reversibly affected but progress irreversibly to: (1) disruption of substrate degradation with pathogenic changes in lysosomal function, (2) cellular dysfunction, secondary/tertiary accumulation (toxins such as GM2 or GM3 ganglioside, etc.), and inflammatory process, and (3) progressive tissue/organ damage and cell death (e.g., skeletal dysplasia, CNS impairment, etc.). For current and future treatment, several potential treatments for MPS that can penetrate the blood-brain barrier and bone have been proposed and/or are in clinical trials, including targeting peptides and molecular Trojan horses such as monoclonal antibodies attached to enzymes via receptor-mediated transport. Gene therapy trials with AAV, ex vivo LV, and Sleeping Beauty transposon system for MPS are proposed and/or underway as innovative therapeutic options. In addition, possible immunomodulatory reagents that can suppress MPS symptoms have been summarized in this review.

Accelerated osteogenesis of bone graft by optimizing the bone microenvironment formed by electrical signals dependent on driving micro vibration stimulation

The strategy of coupling the micro-vibration mechanical field with Ca/P ceramics to optimize the osteogenic microenvironment and enhance the functional activity of the cells can significantly improve the bone regeneration of the graft. However, the regulation mode and mechanism of this coupling strategy are not fully understood at present. This study investigated the influence of different waveforms of the electrical signals driving Microvibration Stimulation (MVS) on this coupling effect. The results showed that there were notable variances in calcium phosphate dissolution and redeposition, protein adsorption, phosphorylation of ERK1/2 and FAK signal pathways and activation of calcium channels such as TRPV1/Piezo1/Piezo2 in osteogenic microenvironment under the coupling action of hydroxyapatite (HA) ceramics and MVS driven by different electrical signal waveforms. Ultimately, these differences affected the osteogenic differentiation process of cells by a way of time-sequential regulation. Square wave-MVS coupled with HA ceramic can significantly delay the high expression time of characteristic genes (such as Runx2, Col-I and OCN) in MC3T3-E1 cells during in vitro the early, middle and late stage of differentiation, while maintain the high proliferative activity of MC3T3-E1 cells. Triangle wave signal-MVS coupled with HA ceramic promoted the osteogenic differentiation of cells in the early and late stages. Sine wave-MVS shows the effect on the process of osteogenic differentiation in the middle stage (such as the up-regulation of ALP synthesis and Col-I gene expression in the early stage of stimulation). In addition, Square wave-MVS showed the best coupling effect. The bone graft constructed under square wave-MVS formed new bone tissue and mature blood vessels only 2 weeks after subcutaneous implantation in nude mice. Our study provides a new non-invasive regulation model for precisely optimizing the osteogenic microenvironment, which can accelerate bone regeneration in bone grafts more safely, accurately and reliably.

A review of glycosaminoglycan-modified electrically conductive polymers for biomedical applications

The application areas of electrically conductive polymers have been steadily growing since their discovery in the late 1970s. Recently, electrically conductive polymers have found their way into biomedicine, allowing the realization of many relevant applications ranging from bioelectronics to scaffolds for tissue engineering. Extracellular matrix components, such as glycosaminoglycans, build an important class of biomaterials that are heavily researched for biomedical applications due to their favorable properties. Due to their highly anionic character and the presence of sulfate groups in glycosaminoglycans, these biomolecules can be employed to functionalize conductive polymers, which enables the tailorability and improvement of cell-material interactions of conductive polymers. This review paper gives an overview of recent research on glycosaminoglycan-modified conductive polymers intended for biomedical applications and discusses the effect of different biological dopants on material characteristics, such as surface roughness, stiffness, and electrochemical properties. Moreover, the key findings of the biological characterization in vitro and in vivo are summarized, and remaining challenges in the field, particularly related to the modification of electrically conductive polymers with glycosaminoglycans to achieve improved functional and biological outcomes, are discussed. STATEMENT OF SIGNIFICANCE: The development of functional biomaterials based on electrically conductive polymers (CPs) for various biomedical applications, such as neural regeneration, drug delivery, or bioelectronics, has been increasingly investigated over the last decades. Recent literature has shown that changes in the synthesis procedure or the chosen dopant could adjust the resulting material characteristics. Hence, an interesting approach lies in using natural biomolecules as dopants for CPs to tailor the biological outcome. This review comprehensively summarizes the state of the art in the field of glycosaminoglycan-modified electrically conductive polymers for the first time, particularly highlighting the effect of the chosen dopant on material characteristics, such as surface morphology or stiffness, electrochemical properties, and consequently, cell-material interactions.

Cytocompatible and osteoinductive cotton cellulose nanofiber/chitosan nanobiocomposite scaffold for bone tissue engineering

Natural polymeric nanobiocomposites hold promise in repairing damaged bone tissue in tissue engineering. These materials create an extracellular matrix (ECM)-like microenvironment that induces stem cell differentiation. In this study, we investigated a new cytocompatible nanobiocomposite made from cotton cellulose nanofibers (CNFs) combined with chitosan polymer to induce osteogenic stem cell differentiation. First, we characterized the chemical composition, nanotopography, swelling properties, and mechanical properties of the cotton CNF/chitosan nanobiocomposite scaffold. Then, we examined the biological characteristics of the nanocomposites to evaluate their cytocompatibility and osteogenic differentiation potential using human mesenchymal stem cells derived from exfoliated deciduous teeth. The results showed that the nanobiocomposite exhibited favorable cytocompatibility and promoted osteogenic differentiation of cells without the need for chemical inducers, as demonstrated by the increase in alkaline phosphatase activity and ECM mineralization. Therefore, the cotton CNF/chitosan nanobiocomposite scaffold holds great promise for bone tissue engineering applications.

Biomaterials and tissue engineering approaches using glycosaminoglycans for tissue repair: Lessons learned from the native extracellular matrix

Glycosaminoglycans (GAGs) are an important component of the extracellular matrix as they influence cell behavior and have been sought for tissue regeneration, biomaterials, and drug delivery applications. GAGs are known to interact with growth factors and other bioactive molecules and impact tissue mechanics. This review provides an overview of native GAGs, their structure, and properties, specifically their interaction with proteins, their effect on cell behavior, and their mechanical role in the ECM. GAGs' function in the extracellular environment is still being understood however, promising studies have led to the development of medical devices and therapies. Native GAGs, including hyaluronic acid, chondroitin sulfate, and heparin, have been widely explored in tissue engineering and biomaterial approaches for tissue repair or replacement. This review focuses on orthopaedic and wound healing applications. The use of GAGs in these applications have had significant advances leading to clinical use. Promising studies using GAG mimetics and future directions are also discussed. STATEMENT OF SIGNIFICANCE: Glycosaminoglycans (GAGs) are an important component of the native extracellular matrix and have shown promise in medical devices and therapies. This review emphasizes the structure and properties of native GAGs, their role in the ECM providing biochemical and mechanical cues that influence cell behavior, and their use in tissue regeneration and biomaterial approaches for orthopaedic and wound healing applications.

Structures, Properties, and Bioengineering Applications of Alginates and Hyaluronic Acid

In recent years, polymeric materials have been used in a wide range of applications in a variety of fields. In particular, in the field of bioengineering, the use of natural biomaterials offers a possible new avenue for the development of products with better biocompatibility, biodegradability, and non-toxicity. This paper reviews the structural and physicochemical properties of alginate and hyaluronic acid, as well as the applications of the modified cross-linked derivatives in tissue engineering and drug delivery. This paper summarizes the application of alginate and hyaluronic acid in bone tissue engineering, wound dressings, and drug carriers. We provide some ideas on how to replace or combine alginate-based composites with hyaluronic-acid-based composites in tissue engineering and drug delivery to achieve better eco-economic value.

Glycosaminoglycans: What Remains To Be Deciphered?

Glycosaminoglycans (GAGs) are complex polysaccharides exhibiting a vast structural diversity and fulfilling various functions mediated by thousands of interactions in the extracellular matrix, at the cell surface, and within the cells where they have been detected in the nucleus. It is known that the chemical groups attached to GAGs and GAG conformations comprise "glycocodes" that are not yet fully deciphered. The molecular context also matters for GAG structures and functions, and the influence of the structure and functions of the proteoglycan core proteins on sulfated GAGs and vice versa warrants further investigation. The lack of dedicated bioinformatic tools for mining GAG data sets contributes to a partial characterization of the structural and functional landscape and interactions of GAGs. These pending issues will benefit from the development of new approaches reviewed here, namely (i) the synthesis of GAG oligosaccharides to build large and diverse GAG libraries, (ii) GAG analysis and sequencing by mass spectrometry (e.g., ion mobility-mass spectrometry), gas-phase infrared spectroscopy, recognition tunnelling nanopores, and molecular modeling to identify bioactive GAG sequences, biophysical methods to investigate binding interfaces, and to expand our knowledge and understanding of glycocodes governing GAG molecular recognition, and (iii) artificial intelligence for in-depth investigation of GAGomic data sets and their integration with proteomics.

Heteropolysaccharides in sustainable corrosion inhibition: 4E (Energy, Economy, Ecology, and Effectivity) dimensions

Carbohydrate polymers (polysaccharides) and their derivatives are widely utilized in sustainable corrosion inhibition (SCI) because of their various fascinating properties including multiple adsorption sites, high solubility and high efficiency. Contrary to traditional synthetic polymer-based corrosion inhibitors, polysaccharides are related to the 4E dimension, which stands for Energy, Economy, Ecology, and Effectivity. Furthermore, they are relatively more environmentally benign, biodegradable, and non-bioaccumulative. The current review describes the SCI features of various heteropolysaccharides, including gum Arabic (GA), glycosaminoglycans (chondroitin-4-sulfate (CS), hyaluronic acid (HA), heparin, etc.), pectin, alginates, and agar for the first time. They demonstrate impressive anticorrosive activity for different metals and alloys in a variety of corrosive electrolytes. Through their adsorption at the metal/electrolyte interface, heteropolysaccharides function by producing a corrosion-protective film. In general, their adsorption follows the Langmuir isotherm model. In their molecular structures, heteropolysaccharides contain several polar functional groups like -OH, -NH₂, -COCH₃, -CH₂OH, cyclic and bridging O, -CH₂SO₃H, -SO₃OH, -COOH, -NHCOCH₃, -OHOR, etc. that serve as adsorption centers when they bind to metallic surfaces.

A comparison of electrosprayed vs vortexed glycosaminoglycan-peptide nanoparticle platform for protection and improved delivery of therapeutic peptides

Therapeutic peptides capable of reducing inflammation via inhibition of the MAP kinase 2 pathway have the potential to reduce inflammation in atopic dermatitis by suppressing secretion of inflammatory cytokines by resident keratinocytes. One of the biggest hurdles to the use of therapeutic peptides, however, is their rapid degradation by intrinsic proteases and peptidases found in serum. Here we introduce a new nanoparticle technology that enhances and extends the bioactivity of a MAP KAP kinase 2 inhibitor peptide (MK2i) via electrostatic complexation with Dermatan sulfate (DS), a glycosaminoglycan, and explore their properties under various conditions. DS-MK2i nanoparticles can be made using electrospray ionization or sonication and vortexing with no stabilizing polymers or crosslinking. Average particle diameter, polydispersity index, and zeta potential were measured over a pH range of 2.5-11.5, in increments of 0.5, in water and at physiological ionic strength. Both particle types were shown to be shelf stable, robust, and behave differently in response to pH. They are also significantly more effective at suppressing cytokine secretion in inflamed, human keratinocytes than peptide alone in the presence of serum, providing a facile method of protecting peptides for therapeutic delivery in conditions such as atopic dermatitis, and abrogating the need for serum-starvation in in vitro testing.

Heparanase is the possible link between monkeypox and Covid-19: robust candidature in the mystic and present perspective

Heparanase (HPSE) is an endoglycosidase cleaves heparan sulfate (HS) and this contributes to the degradation and remodeling of the extracellular matrix. HS cleaved by HPSE induces activation of autophagy and formation of autophagosommes which facilitate binding of HPSE to the HS and subsequent release of growth factors. The interaction between HPSE and HS triggers releases of chemokines and cytokines which affect inflammatory response and cell signaling pathways with development of hyperinflammation, cytokine storm (CS) and coagulopathy. HPSE expression is induced by both SARS-CoV-2 and monkeypox virus (MPXV) leading to induction release of pro-inflammatory cytokines, endothelial dysfunction and thrombotic events. Co-infection of MPX with SARS-CoV-2 may occur as we facing many outbreaks of MPX cases during Covid-19 pandemic. Therefore, targeting of HPSE by specific inhibitors may reduce the risk of complications in both SARS-CoV-2 and MPXV infections. Taken together, HPSE could be a potential link between MPX with SARS-CoV-2 in Covid-19 era.

Monkeypox epidemic at the door: should we remain idly by or prepare strongly?

Monkeypox (MPX) is a common zoonotic disease caused by a double-strand DNA MPX virus (MPXV). MPX was considered a sporadic rare disease causing a mild disease with a low capacity to spread among humans. The clinical picture of human MPX highly resembles smallpox, though early lymphadenopathy in human MPX is the distinguishing sign not present in smallpox. The incubation period is 1-3 weeks, and fever, headache, joint pain, myalgia, and nausea for about 3 days. Skin lesions that appear 1-3 days following fever and lymphadenopathy usually appear simultaneously on the face and periphery. By cross-reactivity and protection, the smallpox vaccine produced 85% protection against infection with Orthopoxviruses, including MPX. Antiviral drugs like tecovirimate and brincidofovir could be effective agents against the development of MPX. MPX epidemics are less reported and described as other life-threatening epidemics, leading to an unclear picture of this disease's pathogenesis, epidemiology, and management. With the recent wide range of MPX outbreaks, immense research is mandatory to revise the importance of MPX pathogenesis and risk for epidemic development worldwide. Therefore, this critical study aimed to review MPX's pathogenesis, epidemiology, and management with possible repurposed drugs.

Aggrecan and Hyaluronan: The Infamous Cartilage Polyelectrolytes - Then and Now

Cartilages are unique in the family of connective tissues in that they contain a high concentration of the glycosaminoglycans, chondroitin sulfate and keratan sulfate attached to the core protein of the proteoglycan, aggrecan. Multiple aggrecan molecules are organized in the extracellular matrix via a domain-specific molecular interaction with hyaluronan and a link protein, and these high molecular weight aggregates are immobilized within the collagen and glycoprotein network. The high negative charge density of glycosaminoglycans provides hydrophilicity, high osmotic swelling pressure and conformational flexibility, which together function to absorb fluctuations in biomechanical stresses on cartilage during movement of an articular joint. We have summarized information on the history and current knowledge obtained by biochemical and genetic approaches, on cell-mediated regulation of aggrecan metabolism and its role in skeletal development, growth as well as during the development of joint disease. In addition, we describe the pathways for hyaluronan metabolism, with particular focus on the role as a "metabolic rheostat" during chondrocyte responses in cartilage remodeling in growth and disease.Future advances in effective therapeutic targeting of cartilage loss during osteoarthritic diseases of the joint as an organ as well as in cartilage tissue engineering would benefit from 'big data' approaches and bioinformatics, to uncover novel feed-forward and feed-back mechanisms for regulating transcription and translation of genes and their integration into cell-specific pathways.

Building, Visualizing, and Analyzing Glycosaminoglycan-Protein Interaction Networks

This chapter describes how to generate, visualize, and analyze interaction networks of glycosaminoglycans (GAGs), which are linear polyanionic polysaccharides mostly located at the cell surface and in the extracellular matrix. The protocol is divided into three major steps: (1) the collection of GAG-mediated interaction data, (2) the visualization of GAG interaction networks, and (3) the computational enrichment analyses of these networks to identify their overrepresented features (e.g., protein domains, location, molecular functions, and biological pathways) compared to a reference proteome. These analyses are critical to interpret GAG interactomic datasets, decipher their specificities and functions, and ultimately identify GAG-protein interactions to target for therapeutic purpose.

Immunomodulatory biomaterials on chemokine signaling in wound healing

Normal wound healing occurs through a careful orchestration of cytokine and chemokine signaling in response to injury. Chemokines are a small family of chemotactic cytokines that are secreted by immune cells in response to injury and are primarily responsible for recruiting appropriate immune cell types to injured tissue at the appropriate time. Dysregulation of chemokine signaling is suspected to contribute to delayed wound healing and chronic wounds in diseased states. Various biomaterials are being used in the development of new therapeutics for wound healing and our understanding of their effects on chemokine signaling is limited. It has been shown that modifications to the physiochemical properties of biomaterials can affect the body's immune reaction. Studying these effects on chemokine expression by various tissues and cell type can help us develop novel biomaterial therapies. In this review, we summarize the current research available on both natural and synthetic biomaterials and their effects on chemokine signaling in wound healing. In our investigation, we conclude that our knowledge of chemokines is still limited and that many in fact share both pro-inflammatory and anti-inflammatory properties. The predominance of either a pro-inflammatory or anti-inflammatory profile is mostly likely dependent on timing after injury and exposure to the biomaterial. More research is needed to better understand the interaction and contribution of biomaterials to chemokine activity in wound healing and their immunomodulatory effects.

Injectable Drug Delivery Systems for Osteoarthritis and Rheumatoid Arthritis

Joint diseases are one of the most common causes of morbidity and disability worldwide. The main diseases that affect joint cartilage are osteoarthritis and rheumatoid arthritis, which require chronic treatment focused on symptomatic relief. Conventional drugs administered through systemic or intra-articular routes have low accumulation and/or retention in articular cartilage, causing dose-limiting toxicities and reduced efficacy. Therefore, there is an urgent need to develop improved strategies for drug delivery, in particular, the use of micro- and nanotechnology-based methods. Encapsulation of therapeutic agents in delivery systems reduces drug efflux from the joint and protects against rapid cellular and enzymatic clearance following intra-articular injection. Consequently, the use of drug delivery systems decreases side effects and increases therapeutic efficacy due to enhanced drug retention in the intra-articular space. Additionally, the frequency of intra-articular administration is reduced, as delivery systems enable sustained drug release. This review summarizes various advanced drug delivery systems, such as nano- and microcarriers, developed for articular cartilage diseases.

3D bioprinting optimization of human mesenchymal stromal cell laden gelatin-alginate-collagen bioink

3D bioprinting technology has gained increased attention in the regenerative medicine and tissue engineering communities over the past decade with their attempts to create functional living tissues and organsde novo. While tissues such as skin, bone, and cartilage have been successfully fabricated using 3D bioprinting, there are still many technical and process driven challenges that must be overcome before a complete tissue engineered solution is realized. Although there may never be a single adopted bioprinting process in the scientific community, adherence to optimized bioprinting protocols could reduce variability and improve precision with the goal of ensuring high quality printed constructs. Here, we report on the bioprinting of a gelatin-alginate-collagen bioink containing human mesenchymal stromal cells (hMSCs) which has been optimized to ensure printing consistency and reliability. The study consists of three phases: a pre-printing phase which focuses on bioink characterization; a printing phase which focuses on bioink extrudability/printability, construct stability, and printing accuracy; and a post-processing phase which focuses on the homogeneity and bioactivity of the encapsulated hMSC printed constructs. The results showed that eight identical constructs containing hMSCs could be reliably and accurately printed into stable cross-hatched structures with a single material preparation, and that batch-to-batch consistency was accurately maintained across all preparations. Analysis of the proliferation, morphology, and differentiation of encapsulated hMSCs within the printed constructs showed that cells were able to form large,interconnected colonies and were capable of robust adipogenic differentiation within 14 d of culturing.