Search Results (162)

Hyaluronic acid (HA) is a key extracellular matrix component of vertebrates, where it mediates cell adhesion, immune regulation, and tissue remodeling through its interaction with specific receptors. Although HA has been detected in a few invertebrate species, the lack of fundamental components of the molecular HA pathway poses relevant objections about its functional role in these species. Mining genomic and transcriptomic data, we considered the conservation of the gene locus encoding for the extracellular link protein (XLINK) in marine mussels as well as its expression patterns. Structural and phylogenetic analyses were undertaken to evaluate possible similarities with vertebrate orthologs and to infer the origin of this gene in invertebrates. Biochemical analysis was used to quantify HA in tissues of Mytilus galloprovincialis. As a result, we confirm that the mussel can produce HA (up to 1.02 ng/mg in mantle) and that its genome encodes two XLINK gene loci. These loci are conserved in Mytilidae species and show a complex evolutionary path. Mussel XLINK genes appeared to be expressed during developmental stages in three mussel species, ranking in the top 100 expressed genes in M. trossulus at 17 h post-fertilization. In conclusion, the presence of HA and an active gene with the potential to bind HA suggests that mussels have the potential to synthesize and use HA and are among the few invertebrates encoding this gene. Full article

This review summarizes the available evidence on hyaluronic acid’s (HA’s) role in immune response. HA is one of many components in the extracellular matrix that transmits signals from the extracellular microenvironment to cellular effector systems in immune cells. The final effect of these interactions depends on the type of cells and receptors used and the size of HA particles. HA’s activation of intracellular signaling pathways leads to an immune response involving the release of pro- or anti-inflammatory cytokines and chemokines. These play a crucial role in defense mechanisms, such as protecting against pathogens and tissue healing after injuries. HA, as a signaling particle, is also involved in the intensification of the cytokine storm during COVID-19. Multifold increases in HA content in the lungs and the strength of its impact on the immune system define an “HA storm”. The molecular mechanisms involved in inflammation and initiation, including the promotion of cancer, also begin in the microenvironment, and hyaluronic acid is a key element. In this paper, we focus on intra- and intercellular signaling pathways using HA participation rather than injection preparation based on HA use for esthetic treatment. Full article

Background: Hyaluronicacid (HA)-conjugated nanocarriers leverage CD44 receptor overexpression on tumor cells for targeted delivery of platinum chemotherapeutics. Methods: This study compares non-functionalized (DDS1) versus HA-conjugated single-walled carbon nanotubes (DDS2) for encapsulation stability and CD44 binding of Cisplatin, Carboplatin, and Lobaplatin. Density Functional Theory calculations employed PBE-GGA with Tkatchenko–Scheffler dispersion and ZORA relativistic treatment, using a finite (8,8) armchair SWCNT (24.6 Å, H-capped) for DDS1 and an EDC/NHS-coupled HA oligomer for DDS2. We computed binding energies, HOMO–LUMO gaps, Molecular Electrostatic Potentials, and energy decompositions. Molecular docking to CD44 (PDB ID: 4PZ3) used Molegro Virtual Docker, validated by re-docking the native HA fragment (RMSD 1.79 Å). Results: DFT binding energies (eV) for DDS2 versus DDS1 were −7.92/−7.48 (Cisplatin), −8.93/−8.30 (Carboplatin), and −9.72/−9.25 (Lobaplatin), indicating enhanced stabilization by HA functionalization. Energy decomposition showed increases of ∼0.4 eV (vdW) and ∼0.2 eV (electrostatic) in DDS2. MEP maps confirmed additional negative-potential regions on DDS2, complementing drug-positive sites. Molecular docking yielded MolDock scores of −171.26 for DDS2 versus −106.68 for DDS1, reflecting stronger CD44 affinity. Docking scores indicate that HA conjugation notably strengthens the predicted affinity of CNT carriers toward the CD44 receptor ($\Delta$Score ≈ −65 kcal mol⁻¹). Conclusions: These results motivate experimental follow-up to confirm whether DDS2 can translate the in silico affinity gains into improved targeted delivery of platinum chemotherapeutics. Full article

The field of cancer therapy is actively pursuing highly effective self-targeted drug delivery materials endowed with exceptional properties. Recently, hyaluronic acid (HA), a naturally occurring polysaccharide, has been recognized as a potential target ligand for CD44 receptors, which are frequently expressed on various solid tumor cells targeted in cancer therapy. HA carbon quantum dots (CQDs) exhibit several advantageous properties, including a high surface area-to-volume ratio, small particle size, biocompatibility, and low cytotoxicity, making them ideal for biomedical applications, such as CD44-targeted drug delivery in ferroptosis-based cancer therapy. In this study, we synthesized HA-CQDs to enhance CD44-mediated ligand–receptor interactions targeting triple-negative breast cancer (TNBC). CQDs facilitate the intracellular generation of reactive oxygen species (ROS), leading to glutathione depletion. These processes result in crucial actions such as the downregulation of glutathione peroxidase 4, downregulation of solute carrier family 7 member 11, and inhibition of cystine intake. The subsequent intracellular ROS, originating from lipid peroxidation, induces ferroptosis. Our HA-CQDs engage CD44 receptors, selectively targeting TNBCs and enhancing cancer recognition. This interaction potentially enhances the nanoplatform-based CD44 targeted therapeutic effects in inducing ferroptosis. Full article

Gut-derived uremic toxins (UTs) contribute to cardiovascular disorders like atherosclerosis and cardiomyopathy in patients with chronic kidney disease (CKD), causing increased cardiovascular morbidity and mortality. The intermediate steps between higher concentrations of gut-derived UTs and organ damage caused by UTs are still insufficiently understood. Glycosaminoglycans (GAGs) as components of the extracellular matrix are known to interact with various ligands such as growth factors or receptors, thereby influencing (patho)physiological processes. We previously found that the UT inorganic phosphate (Pi) induces the synthesis and sulphation of the GAGs heparan sulphate and chondroitin sulphate in the rat vascular smooth muscle cell (VSMC) line A7r5 and in the human endothelial cell (EC) line EA.Hy926. The aim of this study was to investigate if other organic UTs modulate GAGs in vascular cells as well. We treated ex vivo cultures of rat aortic rings as well as primary rat VSMCs and human ECs with the UTs Pi, indoxylsulphate (IS), p-cresylsulphate (pCS), trimethylamine N-oxide (TMAO), and urea, and analyzed the samples by histological staining, qPCR, western blot, HPLC, and colorimetric assays. The UT treatment of aortic rings and cells increased contents of sulphated GAGs and hyaluronic acid. UT-treated cells contained higher amounts of 4S- and 6S-sulphated GAGs compared to controls. This was accompanied by altered expressions of genes and proteins relevant for GAG metabolism. Mechanistically, the effects of the UTs on GAGs involve the activation of the PI3K/Akt pathway and of the transcription factor NF-κB. In conclusion, the UT-induced remodeling of the cardiovascular matrix by upregulation of sulphated GAGs and hyaluronic acid in aortic tissue and vascular cells might be a missing link between gut-derived UT and pathophysiological alterations in the cardiovascular system in the sense of a gut–matrix axis. Full article

Particulate matter (PM) exposure is known to induce significant ocular surface inflammation, necessitating effective therapeutic interventions. This study compared the efficacy of 2% rebamipide (REB) with 0.1% hyaluronic acid (HA) eye drops in investigating the anti-inflammatory and pathogen-clearance effects in a PM-induced ocular surface inflammation model using Sprague–Dawley (SD) rats. Parameters including clinical signs, histological changes, mucin secretions, inflammatory cytokines, mast cell degranulation, dysregulated cell proliferation, and cellular apoptosis were evaluated. 2% REB alleviated ocular surface inflammation by downregulating the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) inflammatory pathway and upregulating epidermal growth factor receptor (EGFR) signaling, thereby enhancing mucin secretion and promoting pathogen clearance. Histopathological analysis, western blot, and immunohistochemical staining revealed a marked reduction in inflammatory markers including MMP-9, IL-1β, TNF-α, IL-17, and CD-4, decreased mast cell degranulation, increased goblet cell density, and enhanced expression of mucins, including MUC5AC and MUC16, in the 2% REB-treated group compared to the 0.1% HA-treated and PM-exposed groups. Moreover, 2% REB demonstrated decreased apoptosis (TUNEL) and reduced uncontrolled cell proliferation (Ki67), indicating improved cellular integrity. In conclusion, 2% REB is a promising treatment option for PM-induced ocular surface inflammation in a rat model compared with 0.1% HA, offering the benefits of reducing inflammation, clearing pathogens, and protecting overall ocular health. Full article

Self-assembling amphiphilic polymers represent highly promising materials with emerging applications across various fields. In these polymers, the presence of hydrophilic and hydrophobic segments within their structure drives the self-assembly process in aqueous environments, leading to organized structures capable of incorporating lipophilic drugs. Their high chemical versatility enables the design of tailored structures to meet specific requirements, such as the active targeting ability, thereby broadening their potential applications. In this work, a polyethylene glycol-phospholipid conjugate was employed to form nanocarriers loaded with a lipophilic derivative of gemcitabine. To achieve nano-assemblies actively targeted towards cancer cells overexpressing the hyaluronic acid (HA) receptor CD44, a HA-phospholipid conjugate was co-formulated in various molar ratios (1%, 10%, and 20%). All formulations exhibited a mean diameter below 130 nm, a negative zeta potential (approximately −30 mV), and a high encapsulation efficiency (above 90%). These nano-assemblies demonstrated stability during storage and effectively released the encapsulated drug in a cell culture medium. Upon incubation with cancer cells, the nano-assemblies were internalized via a CD44 endocytosis-mediated mechanism, with the extent of internalization depending on the HA conjugate content. Consistently, cell viability studies revealed that the nanocarriers decorated with higher amounts of HA exerted a higher cytotoxicity, enabling a fine tuning of the nano-assembly properties. Full article

Stifle joint diseases present a significant challenge in companion animals that often lead to hind limb lameness, with osteoarthritis being a prevalent degenerative condition causing pain and reduced mobility. Regenerative medicine offers a promising avenue for improving treatment outcomes, with a range of emerging therapies showing potential to alleviate symptoms and promote joint health. Among these, hyaluronic acid and platelet-rich plasma have been widely used as intra-articular treatments to enhance joint lubrication, reduce inflammation, and provide symptomatic relief. Interleukin-1 receptor antagonist protein, autologous conditioned serum, and autologous protein solution represent the next generation of regenerative therapies, offering more disease-modifying effects by inhibiting key mediators of joint inflammation. More recently, the MSC-derived secretome has emerged as an innovative, cell-free approach that leverages the diverse bioactive factors secreted by MSCs to support tissue repair and modulate inflammation. This review highlights the evidence base behind these non-cellular orthobiologic treatments for stifle joint disease, aiming to inform veterinary practitioners and owners about available options and their efficacy in supporting conventional treatments. Full article

In most mammals, a withdrawal of the pro-gestational hormone progesterone (P4) is necessary for labor onset. In murine cervix, P4 withdrawal is mediated by enzymes steroid 5-alpha-reductase type 1 (SRD5A1) and 20-alpha-hydroxysteroid-dehydrogenase (20α-HSD). Previously, we have shown that inflammatory stimuli induce 20α-HSD levels in uterine muscle (myometrium). Here, we hypothesized that (1) infectious inflammation alters the levels of both P4-metabolizing enzymes in mouse cervix, which consequently ceases P4-mediated inhibition of cervical remodeling, thereby inducing preterm labor (PTL); (2) a progestin, selective progesterone receptor modulator promegestone (aka R5020), non-metabolizable by 20α-HSD, can block lipopolysaccharide (LPS)-induced PTL in mice by maintaining P4 signaling and preventing cervical remodeling. Using RT-PCR and IHC/IF methods, we evaluated the effect of inflammation on the expression of both enzymes in mouse cervix and determined if R5020 can prevent cervical remodeling and PTL in mice. We found significant induction of SRD5A1 and 20α-HSD proteins (p < 0.01), as well as transcript levels of pro-inflammatory cytokines Il1b, Il6, chemokines Cxcl1, Ccl2, cervical ripening enzyme Has2, hyaluronic acid binding protein/HABP (p < 0.05), and a simultaneous decrease in major extracellular fibrillar proteins, collagen type 1 and type 3 (col1a1, col3a1), in mouse cervix during PTL. The prophylactic administration of R5020 in pregnant mice significantly inhibited cervical remodeling and prevented PTL irrespective of the route of LPS-induction, systemic or local. We concluded that R5020 is a promising novel drug application for preterm birth prevention. Full article

CD44, a pivotal cell surface molecule, plays a crucial role in many cellular functions, including cell-cell interactions, adhesion, and migration. It serves as a receptor for hyaluronic acid and is involved in lymphocyte activation, recirculation, homing, and hematopoiesis. Moreover, CD44 is a commonly used cancer stem cell marker associated with tumor progression and metastasis. The development of CD44 aptamers that specifically target CD44 can be utilized to target CD44-positive cells, including cancer stem cells, and for drug delivery. Building on the primary sequences of our previously selected thioaptamers (TAs) and observed variations, we developed a bead-based X-aptamer (XA) library by conjugating drug-like ligands (X) to the 5-positions of certain uridines on a complete monothioate backbone. From this, we selected an XA with high affinity to the CD44 hyaluronic acid binding domain (HABD) from a large combinatorial X-aptamer library modified with N-acetyl-2,3-dehydro-2-deoxyneuraminic acid (ADDA). This XA demonstrated an enhanced binding affinity for the CD44 protein up to 23-fold. The selected CD44 X-aptamers (both amine form and ADDA form) also showed enhanced binding affinity to CD44-overexpressing human ovarian cancer IGROV cells. Secondary structure predictions of CD44 using MFold identified several binding motifs and smaller constructs of various stem-loop regions. Among our identified binding motifs, X-aptamer motif 3 and motif 5 showed enhanced binding affinity to CD44-overexpressing human ovarian cancer IGROV cells with ADDA form, compared to the binding affinities with amine form and scrambled sequence. The effect of ADDA as a binding affinity enhancer was not uniform within the aptamer, highlighting the importance of optimal ligand positioning. The incorporation of ADDA not only broadened the XA’s chemical diversity but also increased the binding surface area, offering enhanced specificity. Therefore, the strategic use of site-directed modifications allows for fine-tuning aptamer properties and offers a flexible, generalizable framework for developing high-performance aptamers that target a wide range of molecules. Full article

Background: Cutaneous T-cell lymphoma (CTCL) is a type of non-Hodgkin’s lymphoma that primarily affects the skin, rich in hyaluronic acid (HA). HA is a component of the extracellular matrix in the dermis and likely affects the development of CTCL, but the mechanism is poorly understood. Here we show that low-molecular-weight HA (LMWHA) possibly exacerbates CTCL, and bexarotene, already used in CTCL treatment, decreases HA production. Methods: We conducted immunohistochemistry, qRT-PCR, immunoblotting, and HA quantification using both mouse and human specimens to evaluate the impact of HA on CTCL. Additionally, we assessed the effect of bexarotene, which is already used for CTCL treatment, on HA metabolism. Results: HA expression was higher in patients’ serum and skin sections than in healthy controls. HA extracted from the skin of mice inoculated with tumors showed an increase in LMWHA. LMWHA increased lymphoma cell proliferation in vitro and accelerated tumor formation in mice in vivo. LMWHA also created a favorable environment for tumor cells by affecting fibroblasts, vascular endothelial cells, and tumor-associated macrophages. Thus, increased levels of HA, mainly LMWHA, exacerbate CTCL progression by affecting tumor cells and their microenvironment. Bexarotene treatment reduced the amount of total HA in murine tumor-inoculated skin, as well as the supernatant of cultured normal human dermal fibroblasts (NHDFs) and HuT78 cells. Detailed in vitro analyses showed that bexarotene treatment decreased HA synthase (HAS)1 and HAS2 expression in NHDFs and HAS1 and HAS3, and CEMIP expression in HuT78 cells. Chromatin immunoprecipitation assays revealed that bexarotene reduced retinoid X receptor-α binding to the HAS1 and HAS2 promoters in NHDFs. Conclusions: Bexarotene potentially exerts its anti-tumor effect by reducing HA levels through decreased expression of HAS. These findings provide new insights into the process of CTCL development and additional insights regarding bexarotene treatment. Full article

In recent years, hyaluronic acid (HA) has attracted increasing attention as a promising biomaterial for the development of drug delivery systems. Due to its unique properties, such as high biocompatibility, low toxicity, and modifiability, HA is becoming a basis for the creation of targeted drug delivery systems, especially in the field of oncology. Receptors for HA overexpressed in subpopulations of cancer cells, and one of them, CD44, is recognized as a molecular marker for cancer stem cells. This review examines the role of HA and its receptors in health and tumors and analyzes existing HA-based delivery systems and their use in various types of cancer. The development of new HA-based drug delivery systems will bring new opportunities and challenges to anti-cancer therapy. Full article

Buccal drug delivery offers a promising alternative for avoiding gastrointestinal degradation and first-pass metabolism. However, enhancing the buccal epithelial barrier’s permeability remains challenging. This study explores the effects of ethanolic extracts from Citrus medica var. Balady (CM), Citrus medica var. Calabria (CMC), and Origanum dayi (ORD) on buccal epithelium permeability in vitro using a TR146 cell-based model. The cell viability assay revealed that the extracts were non-toxic at the concentration range tested (<0.5% w/v). Surprisingly, none of the tested extracts significantly enhanced the buccal permeability of 40 kDa Fluorescein Isothiocyanate Dextran (FD40). However, the CMC and ORD extracts significantly reduced the epithelial permeability of FD40, mirroring the effects of hyaluronic acid (HA), a known barrier integrity enhancer. The total phenolic content (TPC) analysis suggested a potential link between the phenolic concentration and epithelial barrier reinforcement. The rapid colorimetric response method was applied to assess the interaction of these extracts with biological membranes. The results indicated that HA interacts with cellular membranes via lipid bilayer penetration, whereas the extracts likely influence the barrier integrity through alternative mechanisms, such as ligand–receptor interactions or extracellular matrix modulation. These findings highlight the potential of CMC and ORD extracts as natural agents to enhance buccal epithelial integrity. In conclusion, incorporating these extracts into formulations, such as hydrogels, could offer a cost-effective and biocompatible alternative to HA for improving buccal cavity health. Full article

Hyaluronic acid (HA) is an acidic mucopolysaccharide of animal origin composed of repeating disaccharide units of N-acetylglucosamine and glucuronic acid. Due to its excellent biocompatibility, biodegradability, and selective affinity for CD44 receptors on cell surfaces, HA is widely employed as a drug carrier. In our study, we aimed to target subcellular bacteria by grafting cystamine onto HA scaffolds through an amide reaction, producing a linker responsive to H₂S and pH changes. Subsequently, hydrophobic dodecylamine was attached to HA, forming amphiphilic molecules. These amphiphilic entities can self-assemble into nanomicelles in an aqueous solution, thereby encapsulating the antibacterial agent triclosan (TCS). The resulting HA-based system (HASS-TCS) can be internalized via CD44-mediated endocytosis, releasing substantial amounts of streptomycin and TCS in H₂S-rich and acidic environments. Additionally, HASS-TCS has demonstrated effectiveness in eradicating biofilms and addressing intracellular infections caused by Salmonella. This study underscores a novel pH-sensitive hyaluronic acid-based drug delivery system with significant potential for the effective treatment of intracellular infections. Full article

The skin hydration level is a key factor that influences the physical and mechanical properties of the skin. The stratum corneum (SC), the outermost layer of the epidermis, is responsible for the skin’s barrier function. In this study, we investigated the role of a unique composition of Viola yedoensis extract for its ability to activate CD44, a cell-surface receptor of hyaluronic acid, and aquaporin-3, a water-transporting protein, in human keratinocytes (HaCaT). An ELISA assay evaluating the protein expression levels of CD44, aquaporin-3 (AQP3), filaggrin, and keratin-10 revealed that V. yedoensis extract upregulated the levels of CD44 and AQP3 by 15% and 78%, respectively. Additionally, V. yedoensis extract demonstrated a comparative effect on water vapor flux in TEWL and lipid perturbation in DSC versus the reference, glycerin. In light of this new biological efficacy, a detailed phytochemical characterization was undertaken using an integrated LC-HRMS/MS-based metabolomics approach, which provided further insights on the chemistry of V. yedoensis. This led to the identification of 29 secondary metabolites, 14 of which are reported here for the first time, including esculetin, aesculin, apigenin and kaempferol C-glycosides, megastigmane glycosides, roseoside, platanionoside B, and an eriojaposide B isomer, along with the rare, calenduloside F and esculetin diglucoside, which are reported for the first time from the genus, Viola. Notably, two active components identified in the V. yedoensis extract, namely, aesculin and schaftoside, showed an upregulation of the protein expression of CD44 in HaCaT cells by 123% and 193% within 24 h of treatment, respectively, while aesculin increased AQP3 levels by 46%. Aesculin and schaftoside also significantly upregulated the expression of K-10 levels by 299% and 116%, which was considerably higher than sodium hyaluronate, the positive control. The rationale used to characterize the new structures is outlined along with the related biosynthetic pathways envisioned to generate roseoside and Eriojaposide B. These findings provide new molecular insights to deepen the understanding of how V. yedoensis extract, along with the biomarkers aesculin and schaftoside, restores the skin barrier and skin hydration benefits. Full article