Senescent cells promote breast cancer cells motility by secreting GM-CSF and bFGF that activate the JNK signaling pathway.

BACKGROUND: Cellular senescence can be induced in mammalian tissues by multiple stimuli, including aging, oncogene activation and loss of tumor suppressor genes, and various types of stresses. While senescence is a tumor suppressing mechanism when induced within premalignant or malignant tumor cells, senescent cells can promote cancer development through increased secretion of growth factors, cytokines, chemokines, extracellular matrix, and degradative enzymes, collectively known as senescence-associated secretory phenotype (SASP). Previous studies indicated that senescent cells, through SASP factors, stimulate tumor cell invasion that is a critical step in cancer cell metastasis. METHODS: In the current study, we investigated the effect of senescent cells on the motility of breast cancer cells, which is another key step in cancer cell metastasis. We analyzed the motility of breast cancer cells co-cultured with senescent cells in vitro and metastasis of the breast cancer cells co-injected with senescent cells in orthotopic xenograft models. We also delineated the signaling pathway mediating the effect of senescent cells on cancer cell motility. RESULTS: Our results indicate that senescent cells stimulated the migration of breast cancer cells through secretion of GM-CSF and bFGF, which in turn induced activation of the JNK pathway in cancer cells. More importantly, senescent cells promoted breast cancer metastasis, with a minimum effect on the primary tumor growth, in orthotopic xenograft mouse models. CONCLUSIONS: These results have revealed an additional mechanism by which senescent cells promote tumor cell metastasis and tumor progression, and will potentially lead to identification of novel targets for cancer therapies that suppress metastasis, the major cause of cancer mortality.

Long-term stability of frozen platelet-rich plasma under -80 °C storage condition.

Platelet rich plasma (PRP) is increasingly used in various fields of medicine, aiming to regeneration and repair damaged tissues, cells and organs. High concentration of bioactive molecules including growth factors, cytokines and chemokines are the rationale of using PRP. The aim of this study is to analyze the effect of frozen on the levels of growth factors. In our study, PRP samples were isolated from 50 healthy volunteers using the Trima Accel blood cell separator. The concentration of growth factors such as platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF-1) and platelet factor 4 (PF-4) were assessed in fresh PRP and frozen PRP stored at -80 °C for one to twelve months. The study found that count of platelet in all fresh and frozen PRP samples was significantly increased compared to whole blood baseline. There was no significant difference in the concentrations of PDGF-BB, bFGF, VEGF, and PF-4 between fresh and frozen samples. The concentrations of EGF and IGF in Frozen-PRP group were significantly higher than those in Fresh-PRP group. And the storage condition of -80 °C is suitable for PRP, which will not lead to a decrease in growth factors concentration for at least 6 months.

Liposomal nano-encapsulation of bFGF combined with injectable BSA hydrogel for efficient burn wound healing.

Rapid and scar-free healing of burn wounds is an urgent clinical issue. Basic fibroblast growth factor (bFGF) has been proven to promote the healing of burn wounds by accelerating ECM remodeling and angiogenesis. However, exudates from burn wounds can accelerate bFGF degradation, thereby affecting its bioactivity. This study proposes an effective protection strategy for bFGF that involves encapsulating bFGF in nanoliposomes (bFGF-NLip) and then incorporating bFGF-NLip into a bovine serum albumin (BSA) hydrogel. This hybrid hydrogel system (bFGF-NLip@B) could maintain the activity of bFGF, achieve sustained release, and allow phospholipids and cholesterol to penetrate the skin, thereby enabling bFGF to function in the dermis. The experimental results showed that the hydrogel was injectable with good mechanical properties and biocompatibility. In a mouse scald wound model, owing to the sustained release of bFGF and skin permeation function of the nanoliposomes, the hydrogel promoted granulation formation, collagen deposition, vascular regeneration, and re-epithelialisation, ultimately accelerating wound healing. In addition, the hydrogel effectively inhibited scar formation. This system provides novel insights into the delivery of bFGF and scar-free healing of burn wounds.

Injectable dual drug-loaded thermosensitive liposome-hydrogel composite scaffold for vascularised and innervated bone regeneration.

Adequate blood supply and thorough innervation are essential to the survival of tissue-engineered bones. Though great progress has been created in the application of bone tissue engineering technology to bone defect repair, many challenges remain, such as insufficient vascularisation and deficient innervation in newly regenerated bone. In the present study, we addressed these challenges by manipulating the bone regeneration microenvironment in terms of vascularisation and innervation. We used a novel injectable thermosensitive liposome-hydrogel composite scaffold as a sustained-release carrier for basic fibroblast growth factor (bFGF, which promotes angiogenesis and neurogenic differentiation) and dexamethasone (Dex, which promotes osteogenic differentiation). In vitro biological assessment demonstrated that the composite scaffold had sufficient cell compatibility; it enhanced the capacity for angiogenesis in human umbilical vein endothelial cells, and the capacity for neurogenic/osteogenic differentiation in human bone marrow mesenchymal stem cells. Moreover, the introduction of bFGF/Dex liposome-hydrogel composite scaffold to bone defect sites significantly improved vascularisation and innervated bone regeneration properties in a rabbit cranial defect model. Based on our findings, the regeneration of sufficiently vascularised and innervated bone tissue through a sustained-release scaffold with excellent injectability and body temperature sensitivity represents a promising tactic towards bone defect repair.

Cell Proliferation, Chondrogenic Differentiation, and Cartilaginous Tissue Formation in Recombinant Silk Fibroin with Basic Fibroblast Growth Factor Binding Peptide.

Regeneration of articular cartilage remains a challenge for patients who have undergone cartilage injury, osteochondritis dissecans and osteoarthritis. Here, we describe a new recombinant silk fibroin with basic fibroblast growth factor (bFGF) binding peptide, which has a genetically introduced sequence PLLQATLGGGS, named P7. In this study, we cultured a human mesenchymal cell line derived from bone marrow, UE6E7-16, in wild-type fibroin sponge (FS) and recombinant silk fibroin sponge with P7 peptide (P7 FS). We compared cell proliferation, chondrogenic differentiation and cartilaginous tissue formation between the two types of sponge. After stimulation with bFGF at 3 ng/mL, P7 FS showed significantly higher cell growth (1.2-fold) and higher cellular DNA content (5.6-fold) than did wild-type FS. To promote chondrogenic differentiation, cells were cultured in the presence of TGF-ß at 10 ng/mL for 28 days. Immunostaining of P7 FS showed SOX9-positive cells comparable to wild-type FS. Alcian-Blue staining of P7 FS also showed cartilaginous tissue formation equivalent to wild-type FS. A significant increase in cell proliferation in P7 FS implies future clinical application of this transgenic fibroin for regeneration of articular cartilage. To produce cartilaginous tissue efficiently, transgenic fibroin sponges and culture conditions must be improved. Such changes should include the selection of growth factors involved in chondrogenic differentiation and cartilage formation.

Bioinspired Collagen Scaffold Loaded with bFGF-Overexpressing Human Mesenchymal Stromal Cells Accelerating Diabetic Skin Wound Healing via HIF-1 Signal Pathway Regulated Neovascularization.

The healing of severe chronic skin wounds in chronic diabetic patients is still a huge clinical challenge due to complex regeneration processes and control signals. Therefore, a single approach is difficult in obtaining satisfactory therapeutic efficacy for severe diabetic skin wounds. In this study, we adopted a composite strategy for diabetic skin wound healing. First, we fabricated a collagen-based biomimetic skin scaffold. The human basic fibroblast growth factor (bFGF) gene was electrically transduced into human umbilical cord mesenchymal stromal cells (UC-MSCs), and the stable bFGF-overexpressing UC-MSCs (bFGF-MSCs) clones were screened out. Then, an inspired collagen scaffold loaded with bFGF-MSCs was applied to treat full-thickness skin incision wounds in a streptozotocin-induced diabetic rat model. The mechanism of skin damage repair in diabetes mellitus was investigated using RNA-Seq and Western blot assays. The bioinspired collagen scaffold demonstrated good biocompatibility for skin-regeneration-associated cells such as human fibroblast (HFs) and endothelial cells (ECs). The bioinspired collagen scaffold loaded with bFGF-MSCs accelerated the diabetic full-thickness incision wound healing including cell proliferation enhancement, collagen deposition, and re-epithelialization, compared with other treatments. We also showed that the inspired skin scaffold could enhance the in vitro tube formation of ECs and the early angiogenesis process of the wound tissue in vivo. Further findings revealed enhanced angiogenic potential in ECs stimulated by bFGF-MSCs, evidenced by increased AKT phosphorylation and elevated HIF-1α and HIF-1ß levels, indicating the activation of HIF-1 pathways in diabetic wound healing. Based on the superior biocompatibility and bioactivity, the novel bioinspired skin healing materials composed of the collagen scaffold and bFGF-MSCs will be promising for healing diabetic skin wounds and even other refractory tissue regenerations. The bioinspired collagen scaffold loaded with bFGF-MSCs could accelerate diabetic wound healing via neovascularization by activating HIF-1 pathways.

Basic Fibroblast Growth Factor Supports the Function of Limbal Niche Cells via the Wnt/ß-Catenin Pathway.

Purpose: To test the effects and underlying mechanisms of basic fibroblast growth factor (bFGF) on the limbal niche cell (LNC) function ex vivo. Methods: By using different concentrations of bFGF (0, 4, 8, 12, and 16 ng/mL) and fibroblast growth factor receptor (FGFR) inhibitors, the effects of bFGF on LNC proliferation, expression of stem cell markers, and transcription levels of the ß-catenin were investigated. Single-cell RNA sequencing (scRNA-seq) was used to analyze the action and mechanisms of FGFR subtypes and the Wnt/ß-catenin pathway during LNC culture. An mature corneal epithelial cell (MCEC)/LNC three-dimensional model was constructed to verify whether bFGF activates the Wnt/ß-catenin pathway in LNC by inhibiting FGFR or ß-catenin targets. Results: scRNA-seq showed that FGFR1 is the main receptor in LNC, along with the molecules in the Wnt pathway, including WNT2, FZD7, LRP5, LRP6, and ß-catenin. The 12 ng/mL bFGF treatment group showed higher LNC proliferation rate and transcription levels of OCT4, SOX2, NANOG, and ß-catenin than any other groups (P < 0.001). In the MCEC/LNC co-culture model, MCEC/LNC treated with 12 ng/mL bFGF promoted the aggregation of the spheres than other groups, associated with increased transcription levels of P63α, WNT2, ß-catenin, and a decreased transcription level of CK12 (P < 0.001). Wnt/ß-catenin inhibitor LF3 treatment reversed the abovementioned effect of bFGF. Conclusions: bFGF could maintain and promote the stemness of LNC via the FGFR1/Wnt2/FZD7/LRP6 axis in a concentration-dependent manner.

Characteristics of quiescent adult neural stem cells induced by the bFGF/BMP4 combination or BMP4 alone in vitro.

Bone morphogenetic protein-4 (BMP4) is involved in regulation of neural stem cells (NSCs) proliferation, differentiation, migration and survival. It was previously thought that the treatment of NSCs with BMP4 alone induces astrocytes, whereas the treatment of NSCs with the bFGF/BMP4 combination induces quiescent neural stem cells (qNSCs). In this study, we performed bulk RNA sequencing (RNA-Seq) to compare the transcriptome profiles of BMP4-treated NSCs and bFGF/BMP4-treated NSCs, and found that both NSCs treated by these two methods were Sox2 positive qNSCs which were able to generate neurospheres. However, NSCs treated by those two methods exhibited different characteristics in state and the potential for neuronal differentiation based on transcriptome analysis and experimental results. We found that BMP4-treated NSCs tended to be in a deeper quiescent state than bFGF/BMP4-treated NSCs as the percentage of ki67-positive cells were lower in BMP4-treated NSCs. And after exposure to differentiated environment, bFGF/BMP4-treated NSCs generated more DCX-positive immature neurons and MAP2-positive neurons than BMP4-treated NSCs. Our study characterized qNSCs treated with BMP4 alone and bFGF/BMP4 combination, providing a reference for the scientific use of BMP4 and bFGF/BMP4-induced qNSCs models.

A Biocompatible Nanofibers Modified by Plasma for Osteoblast Growth Differentiation.

This work employs nitrogen plasma immersion ion implantation (PIII) to modify electrospinning polylactic acid membranes and immobilizes basic fibroblast growth factors (bFGF) by forming crosslinking bonds. The study investigates the modified membranes' surface characteristics and the stimulatory effects of crosslinked bFGF polylactic acid membranes on osteoblast and fibroblast proliferation. The PIII process occurs under low vacuum conditions and is controlled by processing time and power pulse width. The experimental results indicate that, within a 400-second N2-PIII treatment, the spun fibers remain undamaged, demonstrating an increase in hydrophilicity (from 117° to 38°/36°) and nitrogen content (from 0% to 7.54%/8.05%). X-ray photoelectron spectroscopy analysis suggests the formation of a C-N-C=O crosslinked bond. Cell culture and activity assessments indicate that the PIII-treated and crosslinked bFGF film exhibits significantly higher cell growth activity (p < 0.05) than the untreated group. These intergroup differences are attributed to the surface crosslinking bond content. In osteogenic induction, the results for each day show that the treated group performs better. However, the intergroup disparities within the crosslinked bFGF group disappear with prolonged culture time due to the rapid osteogenesis prompted by bFGF. The findings suggest that PIII treatment of electrospinning polylactic acid membranes holds promise in promoting osteogenesis in bone tissue scaffolds.

PLA tissue-engineered scaffolds loaded with sustained-release active substance chitosan nanoparticles: Modeling BSA-bFGF as the active substance.

The utilization of basic fibroblast growth factor (bFGF) in the development of tissue-engineered scaffolds is both challenging and imperative. In our pursuit of creating a scaffold that aligns with the natural healing process, we initially fabricated chitosan-bFGF nanoparticles (CS-bFGF NPs) through electrostatic spraying. Subsequently, polylactic acid (PLA) fiber was prepared using electrospinning technique, and the CS-bFGF NPs were uniformly embedded within the pores of porous PLA fibers. Scanning electron micrographs illustrate the smooth surface of the nanoparticles, showing a porous structure intricately attached to PLA fibers. Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) analyses provided conclusive evidence that the CS-bFGF NPs were uniformly distributed throughout the porous PLA fibers, forming a robust physical bond through electrostatic adsorption. The resultant scaffolds exhibited commendable mechanical properties and hydrophilicity, facilitating a sustained-release for 72 h. Furthermore, the biocompatibility and degradation performance of the scaffolds were substantiated by monitoring conductivity and pH changes in pure water over different time intervals, complemented by scanning electron microscopy (SEM) observations. Cell experiments confirmed the cytocompatibility of the scaffolds. In animal studies, the group treated with 16 % NPs/Scaffold demonstrated the highest epidermal reconstruction rate. In summary, our developed materials present a promising candidate for serving as a tissue engineering scaffold, showcasing exceptional biocompatibility, sustained-release characteristics, and substantial potential for promoting epidermal regeneration.

Microneedle fractional radiofrequency associated with drug delivery for facial atrophic acne scars and skin rejuvenation.

Microneedle fractional radiofrequency (MFRF) has been used to improve photoaging and scars. This study aimed to evaluate the efficacy and safety of MFRF with basic fibroblast growth factor (bFGF) for facial atrophic acne scars and skin rejuvenation by blinded visual evaluation, self-report, and reflective confocal microscopy (RCM). Fifteen subjects were randomized to the MFRF with bFGF group and fifteen to the MFRF group. All subjects underwent three-session therapy and a follow-up period. Significant group differences were in ECCA, global improvement score, satisfaction, and downtime before and after treatment. Combination therapy could be more effective than monotherapy for acne scars and facial rejuvenation. In addition, RCM can be used to observe the changes in skin collagen before and after treatment in evaluating cosmetic efficacy.

Modulation of choline and lactate metabolism by basic fibroblast growth factor mitigates neuroinflammation in type 2 diabetes: Insights from 1H-NMR metabolomics analysis.

BACKGROUND: Type 2 diabetes (T2D), a chronic metabolic disease, occurs brain dysfunction accompanied with neuroinflammation and metabolic disorders. The neuroprotective effects of the basic fibroblast growth factor (bFGF) have been well studied. However, the mechanism underlying the anti-inflammatory effects of bFGF remains elusive. METHODS: In this study, db/db mice were employed as an in vivo model, while high glucose (HG)-induced SY5Y cells and LPS-induced BV2 cells were used as in vitro models. Liposomal transfection of MyD88 DNA plasmid was used for MyD88-NF-κB pathway studies. And western blotting, flow cytometry and qPCR were employed. 1H-NMR metabolomics was used to find out metabolic changes. RESULTS: bFGF mitigated neuroinflammatory and metabolic disorders by inhibiting cortical inflammatory factor secretion and microglia hyperactivation in the cortex of db/db mice. Also, bFGF was observed to inhibit the MyD88-NF-κB pathway in high glucose (HG)-induced SY5Y cells and LPS-induced BV2 cells in in vitro experiments. Moreover, the 1H-NMR metabolomics results showed that discernible disparities between the cortical metabolic profiles of bFGF-treated db/db mice and their untreated counterparts. Notably, excessive lactate and choline deficiency attenuated the anti-inflammatory protective effect of bFGF in SY5Y cells. CONCLUSION: bFGF ameliorates neuroinflammation in db/db mice by inhibiting the MyD88-NF-kB pathway. This finding expands the potential application of bFGF in the treatment of neuroinflammation-related cognitive dysfunction.

Electrospray Nano-Micro Composite Sodium Alginate Microspheres with Shape-Adaptive, Antibacterial, and Angiogenic Abilities for Infected Wound Healing.

Nonhealing infectious wounds, characterized by bacterial colonization, wound microenvironment destruction, and shape complexity, present an intractable problem in clinical practice. Inspired by LEGOs, building-block toys that can be assembled into desired shapes, we proposed the use of electrospray nano-micro composite sodium alginate (SA) microspheres with antibacterial and angiogenic properties to fill irregularly shaped wounds instantly. Specifically, porous poly(lactic-co-glycolic acid) (PLGA) microspheres (MSs) encapsulating basic fibroblast growth factor (bFGF) were produced by a water-in-oil-in-water double-emulsion method. Then, bFGF@MSs were blended with the SA solution containing ZIF-8 nanoparticles. The resultant solution was electrosprayed to obtain nano-micro composite microspheres (bFGF@MS/ZIF-8@SAMSs). The composite MSs' size could be regulated by PLGA MS mass proportion and electrospray voltage. Moreover, bFGF, a potent angiogenic agent, and ZIF-8, bactericidal nanoparticles, were found to release from bFGF@MS/ZIF-8@SAMSs in a controlled and sustainable manner, which promoted cell proliferation, migration, and tube formation and killed bacteria. Through experimentation on rat models, bFGF@MS/ZIF-8@SAMSs were revealed to adapt to wound shapes and accelerate infected wound healing because of the synergistic effects of antibacterial and angiogenic abilities. In summation, this study developed a feasible approach to prepare bioactive nano-micro MSs as building blocks that can fill irregularly shaped infected wounds and improve healing.

Integration of Zn2+, ATP, and bFGF to Nanodressing with Core-Shell Structure Fabricated by Emulsion Electrospinning for Wound Healing.

Basic fibroblast growth factor (bFGF) plays an important role in active wound repair. However, the existing dosage forms in clinical applications are mainly sprays and freeze-dried powders, which are prone to inactivation and cannot achieve a controlled release. In this study, a bioactive wound dressing named bFGF-ATP-Zn/polycaprolactone (PCL) nanodressing with a "core-shell" structure was fabricated by emulsion electrospinning, enabling the sustained release of bFGF. Based on the coordination and electrostatic interactions among bFGF, ATP, and Zn2+, as well as their synergistic effect on promoting wound healing, a bFGF-ATP-Zn ternary combination system was prepared with higher cell proliferation activity and used as the water phase for emulsion electrospinning. The bFGF-ATP-Zn/PCL nanodressing demonstrated improved mechanical properties, sustained release of bFGF, cytocompatibility, and hemocompatibility. It increased the proliferation activity of human dermal fibroblasts (HDFs) and enhanced collagen secretion by 1.39 and 3.45 times, respectively, while reducing the hemolysis rate to 3.13%. The application of the bFGF-ATP-Zn/PCL nanodressing in mouse full-thickness skin defect repair showed its ability to accelerate wound healing and reduce wound scarring within 14 days. These results provide a research basis for the development and application of this bioactive wound dressing product.

Modified EBP-bFGF targeting endogenous renal extracellular matrix protects against renal ischemia-reperfusion injury in rats.

Acute kidney injury (AKI) is a life-threatening disease primarily caused by renal ischemia-reperfusion (I/R) injury, which can result in renal failure. Currently, growth factor therapy is considered a promising and effective approach for AKI treatment. Basic fibroblast growth factor (bFGF), an angiogenic factor with potent activity, efficiently stimulates angiogenesis and facilitates regeneration of renal tissue. However, the unrestricted diffusion of bFGF restricts its clinical application in AKI treatment. Therefore, developing a novel sustained released system for bFGF could enhance its potential in treating AKI. In this study, we genetically engineered a multifunctional recombinant protein by fusing bFGF with a specific peptide (EBP). EBP-bFGF effectively binds to the extracellular matrix in the injured kidney, enabling slow release of bFGF in AKI. Furthermore, following orthotopic injection into I/R rats' ischemic kidneys, EBP-bFGF exhibited stable retention within the tissue. Additionally, EBP-bFGF suppressed apoptosis of renal cells, reduced renal fibrosis, and facilitated recovery of renal function. These findings suggest that EBP-bFGF delivery system represents a promising strategy for treating AKI.

All-in-one hydrogel patches with sprayed bFGF-loaded GelMA microspheres for infected wound healing studies.

The current wound healing process faces numerous challenges such as bacterial infection, inflammation and oxidative stress. However, wound dressings used to promote wound healing, are not well suited to meet the clinical needs. Hyaluronic acid (HA) not only has excellent water absorption and good biocompatibility but facilitates cell function and tissue regeneration. Dopamine, on the other hand, increases the overall viscosity of the hydrogel and possesses antioxidant property. Furthermore, chitosan exhibits outstanding performance in antimicrobial, anti-inflammatory and antioxidant activities. Basic fibroblast growth factor (bFGF) is conducive to cell proliferation and migration, vascular regeneration and wound healing. Hence, we designed an all-in-one hydrogel patch containing dopamine and chitosan framed by hyaluronic acid (HDC) with sprayed gelatin methacryloyl (GelMA) microspheres loaded with bFGF (HDC-bFGF). The hydrogel patch exhibits excellent adhesive, anti-inflammatory, antioxidant and antibacterial properties. In vitro experiments, the HDC-bFGF hydrogel patch not only showed significant inhibitory effect on RAW cell inflammation and Staphylococcus aureus (S. aureus) growth but also effectively scavenged free radicals, in addition to promoting the migration of 3 T3 cells. In the mice acute infected wound model, the HDC-bFGF hydrogel patch adhered to the wound surface greatly accelerated the healing process via its anti-inflammatory and antioxidant activities, bacterial inhibition and pro-vascularization effects. Therefore, the multifunctional HDC-bFGF hydrogel patch holds great promise for clinical application.

On Connective Tissue Mast Cells as Protectors of Life, Reproduction, and Progeny.

The connective tissue mast cell (MC), a sentinel tissue-residing secretory immune cell, has been preserved in all vertebrate classes since approximately 500 million years. No physiological role of the MC has yet been established. Considering the power of natural selection of cells during evolution, it is likely that the MCs exert essential yet unidentified life-promoting actions. All vertebrates feature a circulatory system, and the MCs interact readily with the vasculature. It is notable that embryonic MC progenitors are generated from endothelial cells. The MC hosts many surface receptors, enabling its activation via a vast variety of potentially harmful exogenous and endogenous molecules and via reproductive hormones in the female sex organs. Activated MCs release a unique composition of preformed and newly synthesized bioactive molecules, like heparin, histamine, serotonin, proteolytic enzymes, cytokines, chemokines, and growth factors. MCs play important roles in immune responses, tissue remodeling, cell proliferation, angiogenesis, inflammation, wound healing, tissue homeostasis, health, and reproduction. As recently suggested, MCs enable perpetuation of the vertebrates because of key effects-spanning generations-in ovulation and pregnancy, as in life-preserving activities in inflammation and wound healing from birth till reproductive age, thus creating a permanent life-sustaining loop. Here, we present recent advances that further indicate that the MC is a specific life-supporting and progeny-safeguarding cell.

MyoD Over-Expression Rescues GST-bFGF Repressed Myogenesis.

During embryogenesis, basic fibroblast growth factor (bFGF) is released from neural tube and myotome to promote myogenic fate in the somite, and is routinely used for the culture of adult skeletal muscle (SKM) stem cells (MuSC, called satellite cells). However, the mechanism employed by bFGF to promote SKM lineage and MuSC proliferation has not been analyzed in detail. Furthermore, the question of if the post-translational modification (PTM) of bFGF is important to its stemness-promoting effect has not been answered. In this study, GST-bFGF was expressed and purified from E.coli, which lacks the PTM system in eukaryotes. We found that both GST-bFGF and commercially available bFGF activated the Akt-Erk pathway and had strong cell proliferation effect on C2C12 myoblasts and MuSC. GST-bFGF reversibly compromised the myogenesis of C2C12 myoblasts and MuSC, and it increased the expression of Myf5, Pax3/7, and Cyclin D1 but strongly repressed that of MyoD, suggesting the maintenance of myogenic stemness amid repressed MyoD expression. The proliferation effect of GST-bFGF was conserved in C2C12 over-expressed with MyoD (C2C12-tTA-MyoD), implying its independence of the down-regulation of MyoD. In addition, the repressive effect of GST-bFGF on myogenic differentiation was almost totally rescued by the over-expression of MyoD. Together, these evidences suggest that (1) GST-bFGF and bFGF have similar effects on myogenic cell proliferation and differentiation, and (2) GST-bFGF can promote MuSC stemness and proliferation by differentially regulating MRFs and Pax3/7, (3) MyoD repression by GST-bFGF is reversible and independent of the proliferation effect, and (4) GST-bFGF can be a good substitute for bFGF in sustaining MuSC stemness and proliferation.

Enhanced Vascular-like Network Formation of Encapsulated HUVECs and ADSCs Coculture in Growth Factors Conjugated GelMA Hydrogels.

Tissue engineering primarily aimed to alleviate the insufficiency of organ donations worldwide. Nonetheless, the survival of the engineered tissue is often compromised due to the complexity of the natural organ architectures, especially the vascular system inside the organ, which allows food-waste transfer. Thus, vascularization within the engineered tissue is of paramount importance. A critical aspect of this endeavor is the ability to replicate the intricacies of the extracellular matrix and promote the formation of functional vascular networks within engineered constructs. In this study, human adipose-derived stem cells (hADSCs) and human umbilical vein endothelial cells (HUVECs) were cocultured in different types of gelatin methacrylate (GelMA). In brief, pro-angiogenic signaling growth factors (GFs), vascular endothelial growth factor (VEGF165) and basic fibroblast growth factor (bFGF), were conjugated onto GelMA via an EDC/NHS coupling reaction. The GelMA hydrogels conjugated with VEGF165 (GelMA@VEGF165) and bFGF (GelMA@bFGF) showed marginal changes in the chemical and physical characteristics of the GelMA hydrogels. Moreover, the conjugation of these growth factors demonstrated improved cell viability and cell proliferation within the hydrogel construct. Additionally, vascular-like network formation was observed predominantly on GelMA@GrowthFactor (GelMA@GF) hydrogels, particularly on GelMA@bFGF. This study suggests that growth factor-conjugated GelMA hydrogels would be a promising biomaterial for 3D vascular tissue engineering.

A supramolecular hydrogel dressing with antibacterial, immunoregulation, and pro-regeneration ability for biofilm-associated wound healing.

Chronic wound treatment has emerged as a significant healthcare concern worldwide due to its substantial economic burden and the limited effectiveness of current treatments. Effective management of biofilm infections, regulation of excessive oxidative stress, and promotion of tissue regeneration are crucial for addressing chronic wounds. Hydrogel stands out as a promising candidate for chronic wound treatment. However, its clinical application is hindered by the difficulty in designing and fabricating easily and conveniently. To overcome these obstacles, we present a supermolecular G-quadruplex hydrogel with the desired multifunction via a dynamic covalent strategy and Hoogsteen-type hydrogen bonding. The G-quadruplex hydrogel is made from the self-assembly of guanosine, 2-formylphenyboronic acid, polyethylenimine, and potassium chloride, employing dynamic covalent strategy and Hoogsteen-type hydrogen bonding. In the acidic/oxidative microenvironment associated with bacterial infections, the hydrogel undergoes controlled degradation, releasing the polyethylenimine domain, which effectively eliminates bacteria. Furthermore, nanocomplexes comprising guanosine monophosphate and manganese sulfate are incorporated into the hydrogel skeleton, endowing it with the ability to scavenge reactive oxygen species and modulate macrophages. Additionally, the integration of basic fibroblast growth factor into the G-quadruplex skeleton through dynamic covalent bonds facilitates controlled tissue regeneration. In summary, the facile preparation process and the incorporation of multiple functionalities render the G-quadruplex hydrogel a highly promising candidate for advanced wound dressing. It holds great potential to transition from laboratory research to clinical practice, addressing the pressing needs of chronic wound management.