Effects of cell line proliferation on the aggregation and stability of a hyaluronic acid solution (HA)/PLGA microparticles dispersed in the culture system

Rapamycin (rapa), an immunosuppressive medication, has demonstrated considerable effectiveness in reducing organ transplant rejection and treating select autoimmune diseases. However, the standard oral administration of rapa results in poor bioavailability, broad biodistribution, and harmful off-target effects, necessitating improved drug delivery formulations. Polymeric microparticles (MPs) are one such solution and have demonstrated promise in pre-clinical studies to improve the therapeutic efficacy of rapa. Nevertheless, MP formulations are highly diverse, and fabrication method selection is a critical consideration in formulation design. Herein, we compared common fabrication processes for the development of rapa-loaded MPs. Using the biopolymer acetalated dextran (Ace-DEX), rapa-loaded MPs were fabricated by both emulsion (homogenization and sonication) and spray (electrospray and spray drying) methods, and resultant MPs were characterized for size, morphology, surface charge, and drug release kinetics. MPs were then screened in LPS-stimulated macrophages to gauge immunosuppressive efficacy relative to soluble drug. We determined that homogenized MPs possessed the most optimal combination of sizing, tunable drug release kinetics, and immunosuppressive efficacy, and we subsequently demonstrated that these characteristics were maintained across a range of potential rapa loadings. Further, we performed in vivo trafficking studies to evaluate depot kinetics and cellular uptake at the injection site after subcutaneous injection of homogenized MPs. We observed preferential MP uptake by dendritic cells at the depot, highlighting the potential for MPs to direct more targeted drug delivery. Our results emphasize the significance of fabrication method in modulating the efficacy of MP systems and inform improved formulation design for the delivery of rapa.

Carboxymethyl chitosan (CMC)-based hydrogels have emerged as promising candidates for wound dressing applications due to their excellent biocompatibility and tunable physicochemical properties. In this study, a novel hydrogel functionalized with hyaluronic acid (HA) and RGD peptides (RGD) was fabricated and evaluated for its structural characteristics and wound-healing potential. Using CMC as the base matrix and EDC/NHS as crosslinking agents, four hydrogel variants were fabricated: CMC gel, CMC-HA gel, CMC-RGD gel, and CMC-HA-RGD gel. The preliminary cell compatibility experiment identified the optimal formulation as 1% CMC, 0.9% HA, and 0.02 mg/mL RGD, crosslinked with 1 vol% EDC and 0.05 wt% NHS. Scanning electron microscopy showed a porous architecture (100–400 μm), conducive to fibroblast viability and proliferation. Zeta potential measurements (|ζ| > 30 mV) indicated colloidal stability of the hydrogel system. Fourier-transform infrared spectroscopy confirmed successful crosslinking and integration of HA and RGD via hydrogen bonding and electrostatic interactions, forming a stable three-dimensional network. Thermogravimetric analysis revealed enhanced thermal stability upon HA/RGD incorporation. CCK-8 assays demonstrated significantly improved cell viability with HA/RGD loading (p < 0.05), while Ki-67 immunofluorescence confirmed enhanced fibroblast proliferation, with the CMC-HA-RGD gel showing the most pronounced effect. In vitro scratch assay results demonstrated that the CMC-HA-RGD hydrogel dressing significantly enhanced cellular migration compared to other carboxymethyl chitosan-based hydrogel groups (p < 0.05). The observed statistically significant improvement in cell migration rate versus controls underscores the distinctive enhancement of synergistic HA and RGD modification in accelerating cellular migration and facilitating wound repair. Collectively, these findings suggest that the CMC-HA-RGD hydrogel possesses favorable physicochemical and biological properties and holds strong potential as an advanced wound dressing for the treatment of chronic and refractory wounds.

Purpose: To investigate viscosity and wettability of hyaluronic acid (HA) solutions according to supplementation of lysozyme and/or peroxidase, and different ionic strength and pH conditions. Methods: Solutions containing HA were prepared using distilled deionized water (DDW) and simulated salivary buffer (SSB) in different conditions. Different concentrations of hen egg-white lysozyme and bovine lactoperoxidase was added into HA solutions. HA solutions with antimicrobials in different ionic strength and pH conditions were prepared. Viscosity was measured using cone-and-plate digital viscometer at six different shear rates and wettability on acrylic resin and Co-Cr alloy was determined by contact angle. Results: The viscosity values of HA dissolved in DDW were decreased in order of HA, HA containing lysozyme, HA containing peroxidase, and HA containing lysozyme and peroxidase. The viscosity values for HA in DDW were decreased as the concentration of lysozyme and/or peroxidase increased. However, the viscosity values for HA in SSB showed no significant changes according to the concentration of lysozyme and/or peroxidase. The viscosity values of HA solutions were inversely proportional to ionic strength and pH. The contact angle of HA solutions showed no significant differences according to tested surface materials, addition of lysozyme and/or peroxidase, and different ionic strength and pH conditions. Contact angles on acrylic resin by HA solutions in all tested conditions were much higher than those by human saliva. Conclusions: The rheological properties of HA supplemented with lysozyme and/or peroxidase in different ionic strength and pH conditions were objectively confirmed, indicating the possibility of HA with lysozyme and/or peroxidase as main components in the development of effective saliva substitutes.

Photocrosslinkable and self-healable hydrogels of chitosan and hyaluronic acid

Targeted delivery of hyaluronic acid to the ocular surface by a polymer-peptide conjugate system for dry eye disease

Spontaneous Metastasis of Prostate Cancer Is Promoted by Excess Hyaluronan Synthesis and Processing

Hyaluronic acid (HA) is a component of the extracellular matrix that has been shown to play an important role in bone formation, resorption, and mineralization both in vivo and in vitro. We examined the effects of HA at several molecular weights on osteoclast formation and function induced by RANKL (receptor activator of NF-kappa B ligand) in a mouse monocyte cell line (RAW 264.7). HA at M(r) < 8,000 (low molecular weight HA (LMW-HA)) enhanced tartrate-resistant acid phosphatase-positive multinucleated cell formation and tartrate-resistant acid phosphatase activity induced by RANKL in a dose-dependent manner, whereas HA at M(r) > 900,000 (high molecular weight HA (HMW-HA)) showed no effect on osteoclast differentiation. LMW-HA enhanced pit formation induced by RAW 264.7 cells, whereas HMW-HA did not, and LMW-HA stimulated the expression of RANK (receptor activator of NF-kappa B) protein in RAW 264.7 cells. In addition, we found that LMW-HA enhanced the levels of c-Src protein and phosphorylation of ERKs and p38 MAPK in RAW 264.7 cells stimulated with RANKL, whereas the p38 MAPK inhibitor SB203580 inhibited RANKL-induced osteoclast differentiation. This enhancement of c-Src and RANK proteins induced by LMW-HA was inhibited by CD44 function-blocking monoclonal antibody. These results indicate that LMW-HA plays an important role in osteoclast differentiation and function through the interaction of RANKL and RANK.

This study aimed to develop hyaluronan (HA)-based hydrogel microparticles (MPs) loaded with hemin to address the limitations of traditional macroscale hydrogels. The objective is to design MPs such that they can modulate their physicochemical properties. Given the widespread use of ultraviolet C (UVC) light in various industries and the need for protective measures against accidental exposure, this study evaluated the potential of hemin-loaded MPs to protect human dermal fibroblasts from oxidative stress and cell death caused by UVC exposure. Multiple MP formulations were developed and analysed for size, surface charge, swelling behaviour, degradation rate, and radical scavenging capabilities, both with and without hemin loading. The most promising formulations were tested against UVC-exposed cells to assess cell viability, intracellular nitric oxide (˙NO) and reactive oxygen species levels, and protein carbonylation. The fabricated particles were in the form of microneedles, and the degree of their crosslinking and the role of hemin in the chemical crosslinking reaction were found to influence the surface charge and hydrodynamic diameter of the MPs. Increased crosslinking resulted in reduced swelling, slower degradation, and decreased hemin release rate. MPs with a higher degree of swelling were capable of releasing hemin into the culture medium, leading to enhanced bilirubin generation in dermal fibroblasts following cellular uptake. Pre-treatment with these MPs protected the cells from UVC-induced cell death, nitrosative stress, and protein carbonylation. These findings highlight the potential of the studied MPs to release hemin and to minimise the harmful effects of UVC on dermal fibroblasts.

ADAM10 Is the Constitutive Functional Sheddase of CD44 in Human Melanoma Cells

Modern subunit vaccines, which are of high purity compared with traditional vaccines, are often incapable of inducing strong immune responses as necessary to build an immunological memory. The desired level of immune response can be achieved only by codelivering immune-modulating agents along with the antigenic epitopes present in these high-purity formulations. This study aimed to explore the adjuvant effect of nucleotide oligomerization domain (NOD) receptor agonists as immunomodulators encapsulated in polymeric microparticles as carriers. Microparticles (MP) prepared from poly[(rac-lactide)-co-glycolide] (PLGA) (Mn = 5 kDa, PD = 3.2) by the water-in-oil-in-water (w/o/w) emulsion/solvent evaporation technique were characterized in terms of size, surface morphology, payload and endotoxin content. As NOD agonists, N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP; NOD 2) and γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP; NOD 1) were encapsulated. The immunomodulatory potential of these ligand-loaded MP was evaluated with a human acute monocytic leukemia cell line (THP-1X Blue-CD14 cells). The MP prepared had a phagocytosable size (<10 µm) with a unimodal size distribution and low endotoxin content (<0.5 EU/mL). A dose-dependent cell activation could be established for MDP-loaded microparticles. MP with suitable characteristics for phagocytosis can be prepared and loaded with NOD agonists. The capability of these ligand-loaded microparticles to activate monocytes suggests their broader exploration as vaccine carriers.

It has been shown that extracellular glycosaminoglycans (GAGs) limit the gene transfer by cationic lipids and polymers. The purpose of this study was to clarify how interactions with anionic GAGs (hyaluronic acid and heparan sulfate) modify the cellular uptake and distribution of lipoplexes and polyplexes. Experiments on cellular DNA uptake and GFP reporter gene expression showed that decreased gene expression can rarely be explained by lower cellular uptake. In most cases, the cellular uptake is not changed by GAG binding to the lipoplexes or polyplexes. Reporter gene expression is decreased or blocked by heparan sulfate, but it is increased by hyaluronic acid; this suggests that intracellular factors are involved. Confocal microscopy experiments demonstrated that extracellular heparan sulfate and hyaluronic acid are taken into cells both with free and DNA-associated carriers. We conclude that extracellular GAGs may alter both the cellular uptake and the intracellular behavior of the DNA complexes.

Hyaluronan (HA) is an extracellular matrix glycosaminoglycan that interacts with cell-surface receptors, including CD44. Although HA usually exists as a high molecular mass polymer, HA of a much lower molecular mass that shows a variety of biological activities can be detected under certain pathological conditions, particularly in tumors. We previously reported that low molecular weight HAs (LMW-HAs) of a certain size range induce the proteolytic cleavage of CD44 from the surface of tumor cells and promote tumor cell migration in a CD44-dependent manner. Here, we show that MIA PaCa-2, a human pancreatic carcinoma cell line, secreted hyaluronidases abundantly and generated readily detectable levels of LMW-HAs ranging from approximately 10- to 40-mers. This occurred in the absence of any exogenous stimulation. The tumor-derived HA oligosaccharides were able to enhance CD44 cleavage and tumor cell motility. Inhibition of the CD44-HA interaction resulted in the complete abrogation of these cellular events. These results are consistent with the concept that tumor cells generate HA oligosaccha-rides that bind to tumor cell CD44 through the expression of their own constitutive hyaluronidases. This enhances their own CD44 cleavage and cell motility, which would subsequently promote tumor progression. Such an autocrine/paracrine-like process may represent a novel activation mechanism that would facilitate and promote the malignant potential of tumor cells.

Effect of excipients on encapsulation and release of insulin from spray-dried solid lipid microparticles

Surface modified cationic PLGA microparticles as long-acting injectable carriers for intra-articular small molecule drug delivery

From Chemistry to Clinic: Polysaccharide-Bioceramic Composites for Tissue Engineering Applications.