Fibroblast growth factor-2 bound to specific dermal fibroblast-derived extracellular vesicles is protected from degradation

Application of Gelatin/Vanillin/Fe3+/AGP-AgNPs Hydrogels Promotes Wound Contraction, Enhances Dermal Growth Factor Expression, and Minimizes Skin Irritation

This study further investigates the potential of gelatin-based hydrogel cross-linked with vanillin and ferric ion (GVF), combined with andrographolide (AGP) and silver nanoparticles (AgNPs), as an anti-infection biomaterial for wound dressing, aimed at exploring the mechanisms that attenuate inflammation, enhance wound healing rates, and address allergic skin irritation. AGP-AgNPs were evaluated for cytotoxicity in human adult epidermal keratinocytes (HEKa) and the murine macrophage cell line (RAW 264.7), as well as for nitric oxide (NO) production in response to lipopolysaccharide-induced inflammation in RAW 264.7 macrophage cells. Skin-wound specimens from male Wistar rats were histologically analyzed for epidermal thickness and inflammatory changes. The mRNA expression profiling of dermal growth factors was assessed using RT-qPCR, and skin irritation tests were conducted in female New Zealand rabbits. These AGP-AgNPs exhibited significantly lower toxicity in HEKa and no toxicity in RAW 264.7. Interestingly, AGP-AgNPs at specific concentrations produced NO in RAW 264.7 control cells but were more effective in reducing inflammatory NO levels in RAW 264.7 cells pretreated with lipopolysaccharides, suggesting that AGP-AgNP composites are safe and effectively diminish inflammation. Furthermore, a marked increase in epidermal thickness and a reduction in histological inflammatory cells at wound sites were observed in rats treated with AGP-AgNPs/GVF hydrogels over 21 days. Upregulation of dermal genes promoting wound healing, including collagen types I and III, epidermal growth factor, transforming growth factor-beta, fibronectin, and vascular endothelial growth factor, but not fibroblast growth factor, was observed in a time-dependent manner. These results suggest that the anti-inflammatory properties of GVF/AGP-AgNP hydrogels could promote epithelialization, enhance cellular proliferation, support extracellular matrix synthesis, and facilitate angiogenesis. Additionally, rabbit skin in contact with GVF/AGP-AgNP hydrogels consistently displayed reduced levels of erythema and edema, with no swelling, and a standardized scoring system yielded low primary dermal irritation indices for this hydrogel. These findings suggest that the novel GVF/AGP-AgNP hydrogels possess anti-inflammatory-like activity and can modulate dermal growth factors for wound healing. This leads to reduced dermal irritation, making the formulation potentially suitable for safe topical applications in skin and wound care. However, comprehensive human studies and clinical trials should be required in the future.

Current Understanding of Therapeutic and Diagnostic Applications of Exosomes in Pancreatic Cancer

ABSTRACT

Unusual symptoms, rapid progression, lack of reliable early diagnostic biomarkers, and lack of efficient treatment choices are the ongoing challenges of pancreatic cancer. Numerous research studies have demonstrated the correlation between exosomes and various aspects of pancreatic cancer. In light of these facts, exosomes possess the potential to play functional roles in the treatment, prognosis, and diagnosis of the pancreatic cancer. In the present study, we reviewed the most recent developments in approaches for exosome separation, modification, monitoring, and communication. Moreover, we discussed the clinical uses of exosomes as less invasive liquid biopsies and drug carriers and their contribution to the control of angiogenic activity of pancreatic cancer. Better investigation of exosome biology would help to effectively engineer therapeutic exosomes with certain nucleic acids, proteins, and even exogenous drugs as their cargo. Circulating exosomes have shown promise as reliable candidates for pancreatic cancer early diagnosis and monitoring in high-risk people without clinical cancer manifestation. Although we have tried to reflect the status of exosome applications in the treatment and detection of pancreatic cancer, it is evident that further studies and clinical trials are required before exosomes may be employed as a routine therapeutic and diagnostic tools for pancreatic cancer.

The Role of Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles in Modulating Dermal Fibroblast Activity: A Pathway to Enhanced Tissue Regeneration

Extracellular vesicles (EVs) secreted by umbilical cord-derived mesenchymal stem cells (UC-MSCs) hold significant promise as therapeutic agents in regenerative medicine. This study investigates the effects of UC-MSC-derived EVs on dermal fibroblast function, and their potential in wound healing applications. EVs were characterized by nanoparticle tracking analysis and transmission electron microscopy, revealing a mean size of 118.6 nm, consistent with exosomal properties. Dermal fibroblasts were treated with varying concentrations of EVs (25-100 µg/mL), and their impacts on cellular metabolism, mitochondrial activity, reactive oxygen species (ROS) production, wound closure, inflammatory cytokine secretion, growth factor production, and extracellular matrix (ECM) gene expression were evaluated. At lower concentrations (25-50 µg/mL), EVs significantly enhanced fibroblast metabolic and mitochondrial activity. However, higher concentrations (≥75 µg/mL) increased ROS levels, suggesting potential hormetic effects. EVs also modulated inflammation by reducing pro-inflammatory cytokines (IL-6, TNF-α) while promoting pro-regenerative cytokines (IL-33, TGF-β). Treatment with 50 µg/mL of EVs optimally stimulated wound closure and growth factor secretion (VEGF, BDNF, KGF, IGF), and upregulated ECM-related gene expression (type I and III collagen, fibronectin). These findings demonstrate that UC-MSC-derived EVs exert multifaceted effects on dermal fibroblast function, including enhanced cellular energetics, stimulation of cell migration, regulation of inflammation, promotion of growth factor production, and increased ECM synthesis. This study highlights the potential of EVs as a novel therapeutic strategy for wound healing and tissue regeneration, emphasizing the importance of optimizing EV concentration for maximal therapeutic efficacy.

Functional transfer of integrin co-receptor CD98hc by small extracellular vesicles improves wound healing in vivo

Extracellular vesicles (EVs) mediate intercellular communication. EVs are composed of a lipid bilayer and contain cytosolic proteins and RNAs. Studies highlight EVs striking functions in cell-cell crosstalk. Here, we found that small EVs can transfer functional signaling molecules through their lipid bilayer and participate in skin homeostasis. We identified a transmembrane protein CD98hc (a.k.a. SLC3A2), an integrin co-receptor (Itgb1 and Itgb3), implicated in epidermis homeostasis via its capacity in regulating extracellular matrix, as an important mediator of EV-based intercellular communication in vivo. We first demonstrated that healthy dermal fibroblasts produced and secreted EVs bearing characteristic of exosome-like small EVs (sEVs). We show that CD98hc, Itgb1 co-receptor, is present at the surface of sEVs, transferred and stabilized at the plasma membrane. The transferred complex is functional on recipient cells both in vitro and in vivo. Indeed, treatment with sEVs from WT, but not KO cells rescued migratory defects observed either in CD98hc KO dermal fibroblasts or in keratinocytes in vitro. Furthermore, injection of sEVs at the margins of wound in impaired wound healing mouse models (epidermal CD98hc KO mice exhibiting healing defect and elderly mice) improved wound closure in vivo. CD98hc complex transferred from sEVs remained stabilized at least 7 days after injection. Thus, our findings reveal that in vivo treatment with sEVs containing integrin co-receptor CD98hc could improve multiple skin afflictions.

Sticky Polyelectrolyte Shield for Enhancing Biological Half-Life of Growth Factors

Delivery of secretomes, which includes growth factors, cytokines, and mRNA, is critical in regenerative medicine for cell-to-cell communication. However, the harsh in vivo environment presents significant challenges for secretome delivery. Proteolytic enzymes shorten secretomes' half-lives, and secretomes tend to rapidly diffuse at defect sites. Therefore, a delivery system that ensures prolonged retention and enhanced therapeutic efficacy of secretomes is required. In this study, a Coating Optimized Drug Delivery Enhancement (COD2E) system, a coacervate composed of dopamine functionalized fucoidan and poly-l-lysine, was fabricated for secretome delivery. The dopamine modification significantly enhanced adhesive strength (>7-fold) compared to that of the neat coacervates, which enabled rapid (5 min) and uniform coating ability on collagen sponges. The COD2E system was able to encapsulate fibroblast growth factor (FGF2) and prolong the half-life of FGF2. Notably, its efficacy, demonstrated through a single application of FGF2 encapsulated COD2E on collagen sponge, in a wound model demonstrated a successful tissue repair. The COD2E system is an effective growth factor delivery vehicle since it can protect growth factors, has an antioxidant ability, adheres on various material surfaces, and is hemocompatible.

Manufacturing exosomes for wound healing: Comparative analysis of culture media

Mesenchymal stem cell (MSC)-derived exosomes (EXs) have emerged as promising therapeutic agents for wound healing. However, the optimal conditions for manufacturing MSC-derived EXs that maximize their wound-healing potential have yet to be established. Hence, we compared the efficacy of five different MSC culture media, including three different serum-free, a platelet-supplemented, and a fetal bovine serum-supplemented media, in exosome manufacturing for wound healing applications. Although umbilical cord-derived MSCs (UCMSCs) cultured in these media exhibited similar proliferation, morphology, MSC surface marker expression, and stemness, EXs derived from UCMSCs cultured in different culture media displayed varying levels of growth factors and cytokines. Notably, EXs derived from platelet-supplemented media (DM-PLT_EXs) exhibited significantly higher concentrations of keratinocyte growth factor (KGF), vascular endothelial growth factor (VEGF-A), platelet-derived growth factor (PDGF-BB), interleukin 6 (IL-6), interleukin 7 (IL-7), and interleukin 8 (IL-8) than EXs from other media. These differences correlated with the superior capability of DM-PLT_EXs to promote human skin fibroblast proliferation and stimulate angiogenesis of human umbilical vein endothelial cells, making them a more suitable choice for wound healing applications. Our findings emphasize the significance of the culture medium selection in tailoring the therapeutic potential of UCMSC-derived EXs for wound healing.

Novel Factors Regulating Proliferation, Migration, and Differentiation of Fibroblasts, Keratinocytes, and Vascular Smooth Muscle Cells during Wound Healing

Chronic diabetic foot ulcers (DFUs) are a significant complication of diabetes mellitus, often leading to amputation, increased morbidity, and a substantial financial burden. Even with the advancements in the treatment of DFU, the risk of amputation still exists, and this occurs due to the presence of gangrene and osteomyelitis. Nonhealing in a chronic DFU is due to decreased angiogenesis, granulation tissue formation, and extracellular matrix remodeling in the presence of persistent inflammation. During wound healing, the proliferation and migration of fibroblasts, smooth muscle cells, and keratinocytes play a critical role in extracellular matrix (ECM) remodeling, angiogenesis, and epithelialization. The molecular factors regulating the migration, proliferation, and differentiation of these cells are scarcely discussed in the literature. The literature review identifies the key factors influencing the proliferation, migration, and differentiation of fibroblasts, keratinocytes, and vascular smooth muscle cells (VSMCs), which are critical in wound healing. This is followed by a discussion on the various novel factors regulating the migration, proliferation, and differentiation of these cells but not in the context of wound healing; however, they may play a role. Using a network analysis, we examined the interactions between various factors, and the findings suggest that the novel factors identified may play a significant role in promoting angiogenesis, granulation tissue formation, and extracellular matrix remodeling during wound healing or DFU healing. However, these interactions warrant further investigation to establish their role alone or synergistically.

Strategies to enhance the efficacy of FGF2-based therapies for skin wound healing

Basic fibroblast growth factor (FGF2 or bFGF) is critical for optimal wound healing. Experimental studies show that local application of FGF2 is a promising therapeutic approach to stimulate tissue regeneration, including for the treatment of chronic wounds that have a low healing potential or are characterised by a pathologically altered healing process. However, the problem of low efficiency of growth factors application due to their rapid loss of biological activity in the aggressive proteolytic environment of the wound remains. Therefore, ways to preserve the efficacy of FGF2 for wound treatment are being actively developed. This review considers the following strategies to improve the effectiveness of FGF2-based therapy: (1) use of vehicles/carriers for delivery and gradual release of FGF2; (2) chemical modification of FGF2 to increase the stability of the molecule; (3) use of genetic constructs encoding FGF2 for de novo synthesis of protein in the wound. In addition, this review discusses FGF2-based therapeutic strategies that are undergoing clinical trials and demonstrating the efficacy of FGF2 for skin wound healing.

Defining tropism and activity of natural and engineered extracellular vesicles

Extracellular vesicles (EVs) have important roles as mediators of cell-to-cell communication, with physiological functions demonstrated in various in vivo models. Despite advances in our understanding of the biological function of EVs and their potential for use as therapeutics, there are limitations to the clinical approaches for which EVs would be effective. A primary determinant of the biodistribution of EVs is the profile of proteins and other factors on the surface of EVs that define the tropism of EVs in vivo. For example, proteins displayed on the surface of EVs can vary in composition by cell source of the EVs and the microenvironment into which EVs are delivered. In addition, interactions between EVs and recipient cells that determine uptake and endosomal escape in recipient cells affect overall systemic biodistribution. In this review, we discuss the contribution of the EV donor cell and the role of the microenvironment in determining EV tropism and thereby determining the uptake and biological activity of EVs.

Transport and gradient formation of Wnt and Fgf in the early zebrafish gastrula

Within embryonic development, the occurrence of gastrulation is critical in the formation of multiple germ layers with many differentiative abilities. These cells are instructed through exposure to signalling molecules called morphogens. The secretion of morphogens from a source tissue creates a concentration gradient that allows distinct pattern formation in the receiving tissue. This review focuses on the morphogens Wnt and Fgf in zebrafish development. Wnt has been shown to have critical roles throughout gastrulation, including in anteroposterior patterning and neural posterisation. Fgf is also a vital signal, contributing to involution and mesodermal specification. Both morphogens have also been found to work in finely balanced synergy for processes such as neural induction. Thus, the signalling range of Wnts and Fgfs must be strictly controlled to target the correct target cells. Fgf and Wnts signal to local cells as well as to cells in the distance in a highly regulated way, requiring specific dissemination mechanisms that allow efficient and precise signalling over short and long distances. Multiple transportation mechanisms have been discovered to aid in producing a stable morphogen gradient, including short-range diffusion, filopodia-like extensions called cytonemes and extracellular vesicles, mainly exosomes. These mechanisms are specific to the morphogen that they transport and the intended signalling range. This review article discusses how spreading mechanisms in these two morphogenetic systems differ and the consequences on paracrine signalling, hence tissue patterning.