MBG-Modified β-TCP Scaffold Promotes Mesenchymal Stem Cells Adhesion and Osteogenic Differentiation via a FAK/MAPK Signaling Pathway

Biomaterial design for regenerating aged bone: materiobiological advances and paradigmatic shifts

China's aging demographic poses a challenge for treating prevalent bone diseases impacting life quality. As bone regeneration capacity diminishes with age due to cellular dysfunction and inflammation, advanced biomaterials-based approaches offer hope for aged bone regeneration. This review synthesizes materiobiology principles, focusing on biomaterials that target specific biological functions to restore tissue integrity. It covers strategies for stem cell manipulation, regulation of the inflammatory microenvironment, blood vessel regeneration, intervention in bone anabolism and catabolism, and nerve regulation. The review also explores molecular and cellular mechanisms underlying aged bone regeneration and proposes a database-driven design process for future biomaterial development. These insights may also guide therapies for other age-related conditions, contributing to the pursuit of 'healthy aging'.

Bio-integrated scaffold facilitates large bone regeneration dominated by endochondral ossification

Repair of large bone defects caused by severe trauma, non-union fractures, or tumor resection remains challenging because of limited regenerative ability. Typically, these defects heal through mixed routines, including intramembranous ossification (IMO) and endochondral ossification (ECO), with ECO considered more efficient. Current strategies to promote large bone healing via ECO are unstable and require high-dose growth factors or complex cell therapy that cause side effects and raise expense while providing only limited benefit. Herein, we report a bio-integrated scaffold capable of initiating an early hypoxia microenvironment with controllable release of low-dose recombinant bone morphogenetic protein-2 (rhBMP-2), aiming to induce ECO-dominated repair. Specifically, we apply a mesoporous structure to accelerate iron chelation, this promoting early chondrogenesis via deferoxamine (DFO)-induced hypoxia-inducible factor-1α (HIF-1α). Through the delicate segmentation of click-crosslinked PEGylated Poly (glycerol sebacate) (PEGS) layers, we achieve programmed release of low-dose rhBMP-2, which can facilitate cartilage-to-bone transformation while reducing side effect risks. We demonstrate this system can strengthen the ECO healing and convert mixed or mixed or IMO-guided routes to ECO-dominated approach in large-size models with clinical relevance. Collectively, these findings demonstrate a biomaterial-based strategy for driving ECO-dominated healing, paving a promising pave towards its clinical use in addressing large bone defects.

Neoteric Semiembedded β-Tricalcium Phosphate Promotes Osteogenic Differentiation of Mesenchymal Stem Cells under Cyclic Stretch

β-Tricalcium phosphate (β-TCP) is a bioactive material for bone regeneration, but its brittleness limits its use as a standalone scaffold. Therefore, continuous efforts are necessary to effectively integrate β-TCP into polymers, facilitating a sturdy ion exchange for cell regulation. Herein, a novel semiembedded technique was utilized to anchor β-TCP nanoparticles onto the surface of the elastic polymer, followed by hydrophilic modification with the polymerization of dopamine. Cell adhesion and osteogenic differentiation of mesenchymal stem cells (MSCs) under static and dynamic uniaxial cyclic stretching conditions were investigated. The results showed that the new strategy was effective in promoting cell adhesion, proliferation, and osteogenic induction by the sustained release of Ca2+ in the vicinity and creating a reasonable roughness. Specifically, released Ca2+ from β-TCP could activate the calcium signaling pathway, which further upregulated calmodulin and calcium/calmodulin-dependent protein kinase II genes in MSCs. Meanwhile, the roughness of the membrane and the uniaxial cyclic stretching activated the PIEZO1 signaling pathway. Chemical and mechanical stimulation promotes osteogenic differentiation and increases the expression of related genes 2-8-fold. These findings demonstrated that the neoteric semiembedded structure was a promising strategy in controlling both chemical and mechanical factors of biomaterials for cell regulation.

Photocurable 3D-Printed PMBG/TCP Scaffold Coordinated with PTH (1-34) Bidirectionally Regulates Bone Homeostasis to Accelerate Bone Regeneration

Bone defect repair remains a major clinical challenge that requires the construction of scaffolds that can regulate bone homeostasis. In this study, a photo-cured mesoporous bioactive glass (PMBG) precursor is developed as a tricalcium phosphate (TCP) agglomerant to obtain a double-phase PMBG/TCP scaffold via 3D printing. The scaffold exhibits multi-scale porous structures and large surface areas, making it a suitable carrier for the loading of parathyroid hormone (PTH) (1-34), which is used for the treatment of osteoporosis. In vitro and in vivo results demonstrate that PMBG/TCP scaffolds coordinated with PTH (1-34) can regulate bone homeostasis in a bidirectional manner to facilitate bone formation and inhibit bone resorption. Furthermore, bidirectional regulation of bone homeostasis by PTH (1-34) is achieved by inhibiting fibrogenic activation protein (FAP). Thus, PMBG/TCP scaffolds coordinated with PTH (1-34) are viable materials with considerable potential for application in the field of bone regeneration and provide an excellent solution for the design and development of clinical materials.

Osseointegration behavior of carbon fiber reinforced polyetheretherketone composites modified with amino groups: An in vivo study

Polyetheretherketone (PEEK) has become increasingly popular in dentistry and orthopedics due to its excellent chemical stability, reliable biosafety, and low elastic modulus. However, PEEK's biomechanical strength and bioactivity are limited and need to be increased as an implant material. The previous study in vitro has shown that the amino-functionalized carbon fiber reinforced PEEK (A-30%-CPEEK) possessed enhanced mechanical property and bioactivity. This study aims to evaluate the effect of amino groups modification on the osseointegration behavior of carbon fiber reinforced PEEK (30%-CPEEK) in rabbits. Herein, 30%-CPEEK and A-30%-CPEEK implant discs were implanted in rabbit skulls for 5 weeks, with pure titanium implants serving as a control. The bone-forming ability and osseointegration in vivo were systematically investigated by micro-computed tomography analysis, scanning electron microscope observation, and histological evaluation. Our results showed that all detection parameters were significantly different between the A-30%-CPEEK and 30%-CPEEK groups, favoring those in the A-30%-CPEEK, whose appraisal parameters were equal to or better than pure titanium. Therefore, this study supported the importance of amino groups in facilitating the new bone formation and bone-implant integration, suggesting that A-30%-CPEEK with enhanced osseointegration will be a promising material for dental or orthopedic implants.

3D bioprinted poly(lactic acid)/mesoporous bioactive glass based biomimetic scaffold with rapid apatite crystallization and in-vitro Cytocompatability for bone tissue engineering

In the recent years, bone tissue engineering is regarded as the promising solution for treatment of bone defects which arises due to trauma, infection and surgical intervention. In view of this, several polymer or ceramic based constructs are envisaged for bone tissue engineering potential. However, scaffolds based on pure polymeric materials suffer from slow bioactivity characteristics. On the other hand, scaffolds based on ceramic materials do not offer sufficient strength for load bearing applications. In order to overcome these drawbacks, the current work aims to develop mixed matrix scaffolds based on poly (L-lactic acid)/mesoporous bioactive glass composite with the formulation of 30:70 weight ratio, which mimics the natural bone composition. In the current work, PLA/MBG (30:70) composite based bioink suitable for 3D bioprinting is indigenously developed and its rheological characteristics are evaluated. The 3D architecture for PLA/MBG composite scaffold is designed using Solidworks CAD 2015 and the scaffolds are fabricated using pneumatic based 3D bioprinting technology, which has not been documented earlier for this formulation in view of bone tissue engineering to the best of our knowledge. Followed by this, optimization of printing parameters in order to develop 3D PLA/MBG composite constructs with hierarchical pore architecture suitable for bone tissue engineering is performed. The SEM analysis confirmed that the pore size of the 3D printed PLA/MBG composite scaffolds falls in the range of 500-700 μm, which corresponds to the macroporous nature of the scaffolds useful for bone cell growth. The mechanical analysis confirmed the superior compressive modulus and yield strength for PLA/MBG composite scaffold in comparison to neat PLA. The in-vitro bioactivity assessment showed rapid apatite crystallization by attaining Ca/P ratio of 1.66 equivalent to natural bone mineral within 3rd day of SBF treatment for PLA/MBG composite scaffold, thus indicating the excellent bioactivity behaviour. The 3D bioprinted PLA/MBG composite scaffold showed promising response in terms of cell attachment and proliferation, mineralization as well as gene expression characteristics while assessed through of in-vitro biological assessment using MG-63 osteosarcoma cells. In this regard, the 3D bioprinted PLA/MBG scaffold could be applied as potential implant for bone tissue engineering application.

Bone Tissue Condition during Osteosynthesis of a Femoral Shaft Fracture Using Biodegradable Magnesium Implants with an Anticorrosive Coating in Rats with Experimental Osteoporosis

Today, osteoporosis has become a major global health issues. The World Health Organization declares that 320 billion people have osteoporosis now, and more than 1.5 billion osteoporosis traumatic events occur every year. Bones become fragile and fracture risk is high; thus, it is crucial to choose the right biodegradable implants in order to minimize reoperations of patients with systemic osteoporosis. This investigation aimed to carry out a morphological assessment of the state of bone tissue with osteosynthesis of a femoral fracture in rats, using a model of osteoporosis with the installation of magnesium alloy implants coated with hydroxyapatite and sealed with polytetrafluoroethylene. According to this study, the indicators of angiogenesis and bone formation in experimental animals were significantly higher when an implant coated with hydroxyapatite sealed with polytetrafluoroethylene was used, compared to an implant coated only with hydroxyapatite and in rats without an implant. Based on the data obtained, it is possible to consider a magnesium implant coated with hydroxyapatite and sealed with polytetrafluoroethylene as a promising material for fracture therapy in patients with reduced bone density.

Can 3D-Printed Bioactive Glasses Be the Future of Bone Tissue Engineering?

According to the Global Burden of Diseases, Injuries, and Risk Factors Study, cases of bone fracture or injury have increased to 33.4% in the past two decades. Bone-related injuries affect both physical and mental health and increase the morbidity rate. Biopolymers, metals, ceramics, and various biomaterials have been used to synthesize bone implants. Among these, bioactive glasses are one of the most biomimetic materials for human bones. They provide good mechanical properties, biocompatibility, and osteointegrative properties. Owing to these properties, various composites of bioactive glasses have been FDA-approved for diverse bone-related and other applications. However, bone defects and bone injuries require customized designs and replacements. Thus, the three-dimensional (3D) printing of bioactive glass composites has the potential to provide customized bone implants. This review highlights the bottlenecks in 3D printing bioactive glass and provides an overview of different types of 3D printing methods for bioactive glass. Furthermore, this review discusses synthetic and natural bioactive glass composites. This review aims to provide information on bioactive glass biomaterials and their potential in bone tissue engineering.

PCL nanofibrous incorporating unique matrix fusion protein adsorbed mesoporous bioactive glass for bone tissue engineering

Mesoporous bioactive glass (MBG) is a potential biomedical material in bone defect repairment because of its bioactivity, biocompatibility, and osteoinduction properties. Here we report that Mg-doped MBG scaffold with 3:1 Ca/Mg ratio (MBG-Ca/Mg-3) is good for MC3T3-E1 osteoblast differentiation and mineralization. Mimicking bone extracellular matrix structure by electrospinning, we used MBG-Ca/Mg-3 adsorbed with Osteocalcin-Osteopontin-Biglycan (OOB), a new unique matrix fusion protein, to form OOB@MBG-Ca/Mg-3 scaffold, which has multifunctional ability in calvarial bone defect repairment in vivo. Intriguingly, we found that OOB@MBG-Ca/Mg-3 scaffold increases the expression of osteoblastic marker genes, including bone morphogenetic protein (Bmp2), osteopontin (Opn), Osterix, Runx2 through activation of ERK1/2. We concluded that OOB@MBG-Ca/Mg-3 scaffold promotes osteoblast differentiation and mineralization through ERK1/2 pathway and it can also enhance bone formation in vivo, which provides a new biomaterial in bone tissue engineering.

Experimental study on the biocompatibility and osteogenesis induction ability of PLLA/DDM scaffolds

To investigate the characterization and function of a novel porous osteogenic material (PLLA / DDM) containing polylactic acid and demineralized dentin matrix. The surface morphology and composition of the material were observed by SEM and EDS. The physical characteristics of the material were detected by roughness and water contact angle analyses. The rate of weight loss and change in the pH value of the material were observed by scaffold degradation experiments. Four types of material were investigated: polylactic acid (PLLA) scaffold, demineralized dentin matrix (DDM) particles, PLLA/DDM scaffold and a blank control. The osteogenic effect and osteogenic characteristics of the new materials were explored through in vivo and in vitro osteogenic experiments. SEM analysis showed that DDM powder was uniformly distributed in the polylactic acid scaffold, and the water contact angle revealed that the water absorption of the porous scaffold was improved after the addition of DDM powder. The EDS results showed that the peak values of calcium and phosphorus were obviously increased after the addition of DDM powder, and the porosity test showed that the scaffold had higher porosity after the addition of DDM powder. Scaffold degradation experiments revealed that the scaffold gradually degraded with increasing time, and its pH value slightly increased. The results of cell culture and animal model experiments showed that the porous PLLA/DDM scaffold had good bio-compatibility and promoted cell proliferation and differentiation. In histological and micro-CT evaluations, the material showed good bio-compatibility, biodegradability and bone conductivity with host bone tissue in vivo. PLLA / DDM hybrid showed better performance than PLLA or DDM. The biocompatibility and cell growth promoting properties were stronger than those of single material.

Fabrication and characterization of biodegradable zinc matrix composites reinforced by uniformly dispersed beta-tricalcium phosphate via graphene oxide-assisted hetero-agglomeration

The development of biodegradable Zn matrix composites has been considered a promising approach to achieving enhanced mechanical properties, controllable degradation rate, good biocompatibility, and good osseointegration as orthopedic implants. However, scant literature regarding Zn matrix composites has been reported because of the great difficulty in dispersing the nano-sized bioactive reinforcements uniformly within the Zn matrix. In the present study, a novel and effective method were employed to obtain Zn matrix composites reinforced by uniformly dispersed beta-tricalcium phosphate (β-TCP) via graphene oxide (GO)-assisted hetero-agglomeration and subsequent spark plasma sintering process. A very low-content (0.04 vol%) few-layered GO was used as a coupling reagent to connect the Zn matrix and nano-sized TCP particles. In an appropriate polarity solvent, the negatively charged GO sheets could combine with both the positively charged Zn powder and TCP particles by electrostatic attraction and charge neutralization. Due to the nature of hetero-agglomeration, the flexible GO sheet could adhere to the large Zn powder and attracted a certain amount of TCP particles to form a Zn/GO/TCP sandwich structure by charge neutralization thereby forming a uniform dispersion of TCP particles within Zn matrix. After the spark plasma sintering (SPS) process, the TCP particles incorporated with very thin ZnO layers (thickness of a few dozen nanometers) formed a homogeneous and unique 3D network-like distribution in as-sintered TCP/Zn composites. A unique "snap pea"-like structure was confirmed at the grain boundary of α-Zn grains, which consisted of the TCP particles as "pea" and thin ZnO layer as "pod". Due to the uniform dispersion of bioactive TCP particles and unique structure of the TCP incorporating grain boundary, as-sintered 3TCP/Zn matrix composites possessed yield strength (YS) of 140.8 ± 7.7 MPa, failure strain of 36.0 ± 2.8%, the moderate degradation rate of 19.1 ± 3.3 μm·y^-1 and good cytocompatibility to MC3T3-E1 cells. Moreover, osteogenic differentiation activity evaluation revealed that the addition of TCP could significantly improve the expressions of the osteogenic differentiation-related gene (ALP) in MC3T3-E1 cells, thereby resulting in improved osteogenic capability. Therefore, biodegradable 3TCP/Zn matrix composites fabricated by GO-assisted hetero-agglomeration and subsequent SPS process could be a promising material as orthopedic implants.

Targeting integrin αvβ3 with indomethacin inhibits patient-derived xenograft tumour growth and recurrence in oesophageal squamous cell carcinoma

RATIONALE

A high risk of post-operative recurrence contributes to the poor prognosis and low survival rate of oesophageal squamous cell carcinoma (ESCC) patients. Increasing experimental evidence suggests that integrin adhesion receptors, in particular integrin αv (ITGAV), are important for cancer cell survival, proliferation and migration. Therefore, targeting ITGAV may be a rational approach for preventing ESCC recurrence.

MATERIALS AND METHODS

Protein levels of ITGAV were determined in human ESCC tumour tissues using immunohistochemistry. MTT, propidium iodide staining, and annexin V staining were utilized to investigate cell viability, cell cycle progression, and induction of apoptosis, respectively. Computational docking was performed with the Schrödinger Suite software to visualize the interaction between indomethacin and ITGAV. Cell-derived xenograft mouse models, patient-derived xenograft (PDX) mouse models, and a humanized mouse model were employed for in vivo studies.

RESULTS

ITGAV was upregulated in human ESCC tumour tissues and increased ITGAV protein levels were associated with poor prognosis. ITGAV silencing or knockout suppressed ESCC cell growth and metastatic potential. Interestingly, we identified that indomethacin can bind to ITGAV and enhance synovial apoptosis inhibitor 1 (SYVN1)-mediated degradation of ITGAV. Integrin β3, one of the β subunits of ITGAV, was also decreased at the protein level in the indomethacin treatment group. Importantly, indomethacin treatment suppressed ESCC tumour growth and prevented recurrence in a PDX mouse model. Moreover, indomethacin inhibited the activation of cytokine TGFβ, reduced SMAD2/3 phosphorylation, and increased anti-tumour immune responses in a humanized mouse model.

CONCLUSION

ITGAV is a promising therapeutic target for ESCC. Indomethacin can attenuate ESCC growth through binding to ITGAV, promoting SYVN1-mediated ubiquitination of ITGAV, and potentiating cytotoxic CD8+ T cell responses.

Ion release behavior of vanadium-doped mesoporous bioactive glass particles and the effect of the released ions on osteogenic differentiation of BMSCs via the FAK/MAPK signaling pathway

Vanadium is an important trace element in bone and is involved in bone metabolism, bone formation, and bone growth, but the roles of various vanadium ions, especially of pentavalent vanadium, in bone tissue regenerative repair have been underestimated and even misinterpreted for a long time. The main purposes of this study are to investigate the release profile of Si, Ca, P, and V ions from vanadium doped mesoporous bioactive glass (V-MBG) particles and to explore the effect of pentavalent vanadium ions on proliferation and osteogenic differentiation of BMSCs as well as the corresponding osteogenic signaling pathway. On the basis of preparations of V-MBG particles with different pentavalent vanadium contents, the ion release behavior from V-MBG in distilled water and simulated body fluid was systemically investigated. Furthermore, the cytocompatibility and osteogenic effect of V-MBG extracts were studied in rBMSCs, and the related molecular mechanisms were preliminarily discussed. The results of dissolution experiments showed that the V ionic concentration exhibited a burst increase and then a sustained slow increase in the two media. The resultant V ions from 1.0V-MBG, 4.0V-MBG and 10.0V-MBG at 21 days were about 1.1, 5.8, and 12.5 mg L^-1 in water, respectively, and 1.6, 4.8 and 12.8 mg L^-1 in SBF, respectively. The release behaviors of Si, Ca, P, and V ions were evidently affected by high contents of incorporated vanadium. The cellular results indicated that compared to the control and MBG groups, the V(V) ions in V-MBG extracts at about 19.4 μM markedly promoted the proliferation, the gene and protein expression of BMP-2 and COL-I, and the ALP activity of rBMSCs in non-osteoinductive media, but insignificantly stimulated the OCN protein synthesis. More deeply, V(V) ions at about 19.4 μM significantly upregulated the gene and protein expressions of Itga 2b, FAK, and pERK1/2, demonstrating that V(V) ions could regulate osteogenic differentiation of rBMSCs through the activation of the Itga 2b-FAK-MAPK (pERK1/2) signaling pathway. The in vivo results further confirmed that V-MBG induced and promoted new bone formation in the defect area compared to the PGC and PGC/V-M0 groups. These results would contribute to modify the perception about the biocompatibility and osteogenic promotion of pentavalent vanadium at an appropriate concentration.

Regenerative Medicine Technologies to Treat Dental, Oral, and Craniofacial Defects

Additive manufacturing (AM) is the automated production of three-dimensional (3D) structures through successive layer-by-layer deposition of materials directed by computer-aided-design (CAD) software. While current clinical procedures that aim to reconstruct hard and soft tissue defects resulting from periodontal disease, congenital or acquired pathology, and maxillofacial trauma often utilize mass-produced biomaterials created for a variety of surgical indications, AM represents a paradigm shift in manufacturing at the individual patient level. Computer-aided systems employ algorithms to design customized, image-based scaffolds with high external shape complexity and spatial patterning of internal architecture guided by topology optimization. 3D bioprinting and surface modification techniques further enhance scaffold functionalization and osteogenic potential through the incorporation of viable cells, bioactive molecules, biomimetic materials and vectors for transgene expression within the layered architecture. These computational design features enable fabrication of tissue engineering constructs with highly tailored mechanical, structural, and biochemical properties for bone. This review examines key properties of scaffold design, bioresorbable bone scaffolds produced by AM processes, and clinical applications of these regenerative technologies. AM is transforming the field of personalized dental medicine and has great potential to improve regenerative outcomes in patient care.

Regulation of Myogenic Differentiation by Topologically Microgrooved Surfaces for Skeletal Muscle Tissue Engineering

Inspired by the natural topological structure of skeletal muscle tissue, the topological surface construction of bionic scaffolds for skeletal muscle repair has attracted great interest. Many previous studies have focused on the effects of the topological structure on myoblasts. However, these studies used only specific repeating sizes and shapes to achieve the myoblast alignment and myotube formation; moreover, the regulatory effects of the size of a topological structure on myogenic differentiation are often neglected, leading to a lack of guidance for the design of scaffolds for skeletal muscle tissue engineering. In this study, we fabricated a series of microgroove topographies with various widths and depths via a combination of soft lithography and melt-casting and studied their effects on the behaviors of skeletal muscle cells, especially myogenic differentiation, in detail. Microgrooved poly(lactic-co-glycolic acid) substrates were found to effectively regulate the proliferation, myogenic differentiation, and myotube formation of C2C12 cells, and the degree of myogenic differentiation was significantly dependent on signals in response to the size of the microgroove structure. Compared with their depth, the width of the microgroove structures can more strongly affect the myogenic differentiation of C2C12 cells, and the degree of myoblast differentiation was enhanced with increasing groove width. Microgroove structures with relatively large groove widths and small groove depths promoted the myogenic differentiation of C2C12 cells. In addition, the integrin-mediated focal adhesion kinase signaling pathway and MAPK signaling pathway were activated in cells in response to the external topological structure, and the size of the topological structure of the material surface effectively regulated the degree of the cellular response to the external topological structure. These results can guide the design of scaffolds for skeletal muscle tissue engineering and the construction of effective bionic scaffold surfaces for skeletal muscle regeneration.

Designer Hydrogel with Intelligently Switchable Stem-Cell Contact for Incubating Cartilaginous Microtissues

Stem-cell-derived organoid can resemble in vivo tissue counterpart and mimic at least one function of tissue or organ, possessing great potential for biomedical application. The present study develops a hydrogel with cell-responsive switch to guide spontaneous and sequential proliferation and aggregation of adipose-derived stem cells (ASCs) without inputting artificial stimulus for in vitro constructing cartilaginous microtissues with enhanced retention of cell-matrix and cell-cell interactions. Polylactic acid (PLA) rods are surface-aminolyzed by cystamine, followed by being involved in the amidation of poly(( l-glutamic acid) and adipic acid dihydrazide (ADH) to form a hydrogel. Along with tubular pore formation in hydrogel after dissolution of PLA rods, aminolyzed PLA molecules with disulfide bonds on rod surfaces are covalently transferred to the tubular pore surfaces of poly(l-glutamic acid)/ADH hydrogel. Because PLA attaches cells, while poly(l-glutamic acid)/ADH hydrogel repels cells, ASCs are found to adhere and proliferate on the tubular pore surfaces of hydrogel first and then cleave disulfide bonds by secreting molecules containing thiol, thus inducing desorption of PLA molecules and leading to their spontaneous detachment and aggregation. Associated with chondrogenic induction by TGF-β1 and IGF-1 in vitro for 28 days, the hydrogel as an all-in-one incubator produces well-engineered columnar cartilage microtissues from ASCs, with the glycosaminoglycans (GAGs) and collagen type II (COL II) deposition achieving 64 and 69% of those in chondrocytes pellet, respectively. The cartilage microtissues further matured in vivo for 8 weeks to exhibit extremely similar histological features and biomechanical performance to native hyaline cartilage. The GAGs and COL II content, as well as compressive modulus of the matured tissue show no significant difference with native cartilage. The designer hydrogel may hold a promise for long-term culture of other types of stem cells and organoids.

CircRNA-vgll3 promotes osteogenic differentiation of adipose-derived mesenchymal stem cells via modulating miRNA-dependent integrin α5 expression

Adipose-derived mesenchymal stem cells (ADSCs) are promising candidate for regenerative medicine to repair non-healing bone defects due to their high and easy availability. However, the limited osteogenic differentiation potential greatly hinders the clinical application of ADSCs in bone repair. Accumulating evidences demonstrate that circular RNAs (circRNAs) are involved in stem/progenitor cell fate determination, but their specific role in stem/progenitor cell osteogenesis, remains mostly undescribed. Here, we show that circRNA-vgll3 originating from the vgll3 locus markedly enhances osteogenic differentiation of ADSCs; nevertheless, silencing of circRNA-vgll3 dramatically attenuates ADSC osteogenesis. Furthermore, we validate that circRNA-vgll3 functions in ADSC osteogenesis through a circRNA-vgll3/miR-326-5p/integrin α5 (Itga5) pathway. Itga5 promotes ADSC osteogenic differentiation and miR-326-5p suppresses Itga5 translation. CircRNA-vgll3 directly sequesters miR-326-5p in the cytoplasm and inhibits its activity to promote osteogenic differentiation. Moreover, the therapeutic potential of circRNA-vgll3-modified ADSCs with calcium phosphate cement (CPC) scaffolds was systematically evaluated in a critical-sized defect model in rats. Our results demonstrate that circRNA-vgll3 markedly enhances new bone formation with upregulated bone mineral density, bone volume/tissue volume, trabeculae number, and increased new bone generation. This study reveals the important role of circRNA-vgll3 during new bone biogenesis. Thus, circRNA-vgll3 engineered ADSCs may be effective potential therapeutic targets for bone regenerative medicine.

Fabrication of Injectable, Porous Hyaluronic Acid Hydrogel Based on an In-Situ Bubble-Forming Hydrogel Entrapment Process

Injectable hydrogels have been widely applied in the field of regenerative medicine. However, current techniques for injectable hydrogels are facing a challenge when trying to generate a biomimetic, porous architecture that is well-acknowledged to facilitate cell behaviors. In this study, an injectable, interconnected, porous hyaluronic acid (HA) hydrogel based on an in-situ bubble self-generation and entrapment process was developed. Through an amide reaction between HA and cystamine dihydrochloride activated by EDC/NHS, CO2 bubbles were generated and were subsequently entrapped inside the substrate due to a rapid gelation-induced retention effect. HA hydrogels with different molecular weights and concentrations were prepared and the effects of the hydrogel precursor solution's concentration and viscosity on the properties of hydrogels were investigated. The results showed that HA10-10 (10 wt.%, MW 100,000 Da) and HA20-2.5 (2.5 wt.%, MW 200,000 Da) exhibited desirable gelation and obvious porous structure. Moreover, HA10-10 represented a high elastic modulus (32 kPa). According to the further in vitro and in vivo studies, all the hydrogels prepared in this study show favorable biocompatibility for desirable cell behaviors and mild host response. Overall, such an in-situ hydrogel with a self-forming bubble and entrapment strategy is believed to provide a robust and versatile platform to engineer injectable hydrogels for a variety of applications in tissue engineering, regenerative medicine, and personalized therapeutics.

Micro/nano-hierarchical scaffold fabricated using a cell electrospinning/3D printing process for co-culturing myoblasts and HUVECs to induce myoblast alignment and differentiation

Human skeletal muscle is composed of intricate anatomical structures, including uniaxially arranged myotubes and widely distributed blood capillaries. In this regard, vascularization is an essential part of the successful development of an engineered skeletal muscle tissue to restore its function and physiological activities. In this paper, we propose a method to obtain a platform for co-culturing human umbilical vein endothelial cells (HUVECs) and C2C12 cells using cell electrospinning and 3D bioprinting. To elaborate, on the surface of mechanical supporters (polycaprolactone and collagen struts) with a topographical cue, HUVECs-laden alginate bioink was uniaxially electrospun. The electrospun HUVECs showed high cell viability (90%), homogeneous cell distribution, and efficient HUVEC growth. Furthermore, the myoblasts (C2C12 cells), which were seeded on the vascularized structure (HUVECs-laden fibers), were co-cultured to facilitate myoblast regeneration. As a result, the scaffold that included myoblasts and HUVECs represented a high degree of the myosin heavy chain (MHC) with striated patterns and enhanced myogenic-specific gene expressions (MyoD, troponin T, MHC and myogenin) as compared to the scaffold that included only myoblasts. STATEMENT OF SIGNIFICANCE: Cell electrospinning is an advanced electrospinning method that improves cell-matrix interactions by embedding cells directly into micro/nanofibers. Here, cell electrospinning was employed to achieve not only the homogeneous human umbilical vein endothelial cells (HUVECs) distribution with a high cell-viability (~90%), but also highly aligned topographical cue. Moreover, the uniaxially micropatterned PCL/collagen struts as a physical support were generated using three-dimensional (3D) printing, and was covered with HUVEC-laden micro/nanofibers. This hierarchical structure provided meaningful mechanical stability, homogeneous cell distribution, and HUVEC transformation into a narrow, elongated structure. Furthermore, the myoblasts (C2C12 cells) were seeded on the HUVECs-laden fibers and cocultured to facilitate myogenesis. In brief, a myosin heavy chain with striated patterns and enhanced myogenic specific gene expressions were represented.

Biomimetic Bilayer Scaffold as an Incubator to Induce Sequential Chondrogenesis and Osteogenesis of Adipose Derived Stem Cells for Construction of Osteochondral Tissue

Toward osteochondral tissue construction, the present study introduced a bilayer scaffold to induce sequential chondrogenesis and osteogenesis of stem cells in vitro. Two scaffolds that are both based on poly(l-glutamic acid) (PLGA) and chitosan (CS) were combined to form the bilayer scaffold. The cartilage region was the covalently cross-linked PLGA/CS hydrogel with a tubular pore structure, possessing a swollen network to prevent cellular adhesion, while inducing spontaneous cellular aggregate formation. The bone region was the electrostatically cross-linked PLGA-grafted nano hydroxyapatite (nHA-g-PLGA)/CS scaffold, which supported cellular adhesion and spreading. Human adipose derived stem cells (hASCs) were seeded into the cartilage region and observed to aggregate, formimg multicellular spheroids, which subsequently fused to rod-like aggregates with a larger size. At the same time, hASCs in aggregates crossed the interface and entered the bone region, presenting adhesion and spreading. With the induction of bone morphogenetic protein 2 (BMP-2) and insulin-like growth factor 1 (IGF-1) during the first 14 days and BMP-2 alone during the last 14 days, hASCs aggregates in the cartilage region underwent chondrogenesis, expressing an abundant cartilage matrix including glycosaminoglycans (GAGs) and type II collagen (COL II) at 28 days. The chondrogenic induced hASCs migrated in the bone region turned to osteogenesis at 28 days, which was associated with their large spreading area and the switch of the induce factor. Thus, the present bilayer scaffold induced the different distribution of hASCs, resulting in subsequent chondrogenesis and osteogenesis, realizing osteochondral tissue construction in vitro.

Positive role of calcium phosphate ceramics regulated inflammation in the osteogenic differentiation of mesenchymal stem cells

Recently, researches have confirmed the crucial role of inflammatory response in Ca-P ceramic-induced osteogenesis, however, the underlying mechanism has not yet been fully understood. In this study, BCP and β-TCP ceramics were used as material models to investigate the effect of physicochemical properties on inflammatory response in vitro. The results showed that BCP and β-TCP could support macrophages attachment, proliferation, and spreading favorably, as well as promote gene expressions of inflammatory related cytokines (IL-1, IL-6, MCP-1, and TNF-α) and growth factors (TGF-β, FGF, PDGF, VEGF, IGF, and EGF). BCP showed a facilitating function on the gene expressions earlier than β-TCP. Further coculture experiments performed in vitro demonstrated that the CMs containing various increased cytokines for macrophages pre-culture could significantly promote MSCs osteogenic differentiation, which was confirmed by the gene expressions of osteogenic specific markers and the intracellular OCN product accumulation under the stimulation of BCP and β-TCP ceramics. Further evidence was found from the formation of mineralized nodules in BCM and TCM. In addition, this study showed a concise relationship between Ca-P ceramic induced inflammation and its osteoinductivity that the increased cytokines and growth factors from macrophages could promote MSCs osteogenic differentiation.

Effect of focal adhesion kinase inhibition on osteoblastic cells grown on titanium with different topographies

Objective

The present study aimed to investigate the participation of focal adhesion kinases (FAK) in interactions between osteoblastic cells and titanium (Ti) surfaces with three different topographies, namely, untreated (US), microstructured (MS), and nanostructured (NS).

Methodology

Osteoblasts harvested from the calvarial bones of 3-day-old rats were cultured on US, MS and NS discs in the presence of PF-573228 (FAK inhibitor) to evaluate osteoblastic differentiation. After 24 h, we evaluated osteoblast morphology and vinculin expression, and on day 10, the following parameters: gene expression of osteoblastic markers and integrin signaling components, FAK protein expression and alkaline phosphatase (ALP) activity. A smooth surface, porosities at the microscale level, and nanocavities were observed in US, MS, and NS, respectively.

Results

FAK inhibition decreased the number of filopodia in cells grown on US and MS compared with that in NS. FAK inhibition decreased the gene expression of Alp, bone sialoprotein, osteocalcin, and ALP activity in cells grown on all evaluated surfaces. FAK inhibition did not affect the gene expression of Fak, integrin alpha 1 ( Itga1 ) and integrin beta 1 ( Itgb1 ) in cells grown on MS, increased the gene expression of Fak in cells grown on NS, and increased the gene expression of Itga1 and Itgb1 in cells grown on US and NS. Moreover, FAK protein expression decreased in cells cultured on US but increased in cells cultured on MS and NS after FAK inhibition; no difference in the expression of vinculin was observed among cells grown on all surfaces.

Conclusions

Our data demonstrate the relevance of FAK in the interactions between osteoblastic cells and Ti surfaces regardless of surface topography. Nanotopography positively regulated FAK expression and integrin signaling pathway components during osteoblast differentiation. In this context, the development of Ti surfaces with the ability to upregulate FAK activity could positively impact the process of implant osseointegration.

Exosomes: A Novel Therapeutic Agent for Cartilage and Bone Tissue Regeneration

Despite traditionally treating autologous and allogeneic transplantation and emerging tissue engineering (TE)-based therapies, which have commonly performed in clinic for skeletal diseases, as the "gold standard" for care, undesirably low efficacy and other complications remain. Therefore, exploring new strategies with better therapeutic outcomes and lower incidences of unfavorable side effect is imperative. Recently, exosomes, secreted microvesicles of endocytic origin, have caught researcher's eyes in tissue regeneration fields, especially in cartilage and bone-related regeneration. Multiple researchers have demonstrated the crucial roles of exosomes throughout every developing stage of cartilage and bone tissue regeneration, indicating that there may be a potential therapeutic application of exosomes in future clinical use. Herein, we summarize the function of exosomes derived from the primary cells functioning in skeletal diseases and their restoration processes, therapeutic exosomes used to promote cartilage and bone repairing in recent research, and applications of exosomes within the setting of the TE matrix.

Optimized Synthesis of Biodegradable Elastomer PEGylated Poly(glycerol sebacate) and Their Biomedical Application

Poly(glycerol sebacate) (PGS), a biodegradable elastomer, has been extensively explored in biomedical applications for its favorable mechanical properties and biocompatibility. Efforts have been made to fabricate multifunctional PGS copolymer in recent years, in particular PGS-co-PEG (poly(glycerol sebacate)-co-polyethylene glycol) polymers. However, rare research has been systematically conducted on the effect of reactant ratios on physicochemical properties and biocompatibility of PGS copolymer till now. In this study, a serial of PEGylated PGS (PEGS) with PEG content from 20% to 40% and carboxyl to hydroxyl from 0.67 to 2 were synthesized by thermal curing process. The effects of various PEGS on the mechanical strength and biological activity were further compared and optimized. The results showed that the PEGS elastomers around 20PEGS-1.0C/H and 40PEGS-1.5C/H exhibited the desirable hydrophilicity, degradation behaviors, mechanical properties and cell viability. Subsequently, the potential applications of the 20PEGS-1.0C/H and 40PEGS-1.5C/H in bone repair scaffold and vascular reconstruction were investigated and the results showed that 20PEGS-1.0C/H and 40PEGS-1.5C/H could significantly improve the mechanical strength for the calcium phosphate scaffolds and exhibited preferable molding capability for fabrication of the vascular substitute. These results confirmed that the optimized PEGS elastomers should be promising multifunctional substrates in biomedical applications.

A mechanically robust and flexible PEGylated poly(glycerol sebacate)/β-TCP nanoparticle composite membrane for guided bone regeneration

A PEGS/β-TCP composite membrane was fabricated by a simple prepolymer mixing-in situ crosslinking method for guided bone regeneration.

Amorphous carbon modification on implant surface: a general strategy to enhance osteogenic differentiation for diverse biomaterials via FAK/ERK1/2 signaling pathways

Amorphous carbon coatings enhance osteogenic differentiation via FAK/ERK1/2 signaling pathways.

Functionalized Scaffold for in Situ Efficient Gene Transfection of Mesenchymal Stem Cells Spheroids toward Chondrogenesis

Multicellular mesenchymal stem cell (MSC) spheroids possess enhanced chondrogenesis ability and limited fibrosis, exhibiting advantage toward hyaline-like cartilage regeneration. However, because of the limited cell surfaces in spheroid exposed to DNA/vector, it is difficult to realize efficient gene transfection, most of which highly rely on cell-substrate interaction. Here, we report a poly(l-glutamic acid)-based porous scaffold with tunable inner surfaces that can sequentially realize cell-scaffold attachment and detachment, as well as the followed in situ spheroid formation. The attachment and detachment of cells from scaffold is achieved by the capture and release of fibronectin (Fn) via reversible imine linkage between aromatic aldehyde groups of scaffold and amino groups of Fn. Together with N, N, N-trimethyl chitosan chloride condensing plasmid DNA encoding transforming growth factor-β1 (pDNA-TGF-β1), cell attachment realizes efficient surface-mediated gene transfection. Conversion of scaffold stiffness can affect the adhesion shape of cells. Stiffer scaffold reinforces the adhesion, leading to the amplification of peripheral focal adhesions and the promotion of cell spreading, as well as the promotion of gene transfection efficiency. After cellular detachment from the scaffold via lysine treatment, the subsequent spheroid formation with extensive cell-cell interaction up-regulates the corresponding protein expression with a prolonged term. With the induction effect of the expressed TGF-β1, significantly enhanced chondrogenesis of MSCs in spheroids is achieved at 10 d in vitro. Well-regenerated cartilage at 8 weeks in vivo indicates that the present gene transfection system is a platform that can be potentially applied toward cartilage tissue engineering.

Differential Expression Profiles of Circular RNAs During Osteogenic Differentiation of Mouse Adipose-Derived Stromal Cells

Osteogenesis is a complex and tightly regulated process. Circular RNAs (circRNAs) are covalently closed RNA molecules which are thought to play a significant role in bone metabolism. The purpose of this study was to investigate the expression and putative function of circRNAs during the osteogenic differentiation of mouse adipose-derived stromal cells (mADSCs). circRNA microarrays were used to determine differential circRNAs expression at different stages during osteogenesis of mADSCs. The most frequent differentially expressed circRNAs were selected by Venn analysis and clustered among the three induced groups. In addition, bioinformatic analyses (gene ontology, pathway, and co-expression network analysis) were used to further investigate these differentially expressed circRNAs. A total of 14,236 circRNAs were detected, of which 43 circRNAs (40 upregulated) were consistently altered at indicated time points during osteogenic differentiation of mADSCs. The exonic circRNAs represented a significantly larger proportion among the differentially expressed circRNAs compared to other types of circRNAs. Gene ontology and Kyoto Encyclopedia of Genes and Genomes biological pathway analysis were performed to evaluate the functions of differentially expressed circRNAs during the osteogenic process. Our circRNA-miRNA co-expression network showed that miR-338-3p was correlated with upregulation of two circRNAs (mmu_circRNA_013422, mmu_circRNA_22566). Our data on circRNA expression profiles may provide valuable insight into circRNA function during osteogenic differentiation of mADSCs. Additionally, the circRNA-miRNA-mRNA pathways may provide information on novel mechanisms and targets for clinical investigations on bone formation and regeneration.

JAM-A knockdown accelerates the proliferation and migration of human keratinocytes, and improves wound healing in rats via FAK/Erk signaling

Junctional adhesion molecule-A (JAM-A) belongs to the immunoglobulin superfamily, it predominantly exists at the tight junctions of epithelial and endothelial cells. JAM-A is known to regulate leukocyte trans-endothelial migration, however, how it affects the proliferation and migration of keratinocytes, the two essential steps during wound healing, has less been explored. In this study, we showed that JAM-A was significantly expressed in normal skin epidermis. RNAi-mediated JAM-A knockdown remarkably promoted the proliferation and migration of keratinocytes. We also found that loss of JAM-A increased the protein levels of p-FAK, p-Erk1/2, and p-JNK; however, FAK inhibitor PF-562271 restrained the expression of p-FAK and p-Erk1/2 elevated by JAM-A RNAi, but not p-JNK, and also slowed down keratinocyte proliferation and migration. Finally, in a rat wound model we showed that absence of JAM-A significantly promoted the wound healing process, while the use of PF-562271 or Erk1/2 inhibitor PD98059 repressed those effects. These data collectively demonstrate that suppressing JAM-A expression could promote the proliferation and migration of keratinocytes and accelerate the healing process of rat skin wounds, potentially via FAK/Erk pathway, indicating that JAM-A might serve as a potential therapeutic target for the treatment of chronic refractory wounds.

In vitro response of mesenchymal stem cells to biomimetic hydroxyapatite substrates: A new strategy to assess the effect of ion exchange

Biomaterials can interact with cells directly, that is, by direct contact of the cells with the material surface, or indirectly, through soluble species that can be released to or uptaken from the surrounding fluids. However, it is difficult to characterise the relevance of this fluid-mediated interaction separately from the topography and composition of the substrate, because they are coupled variables. These fluid-mediated interactions are amplified in the case of highly reactive calcium phosphates (CaPs) such as biomimetic calcium deficient hydroxyapatite (CDHA), particularly in static in vitro cultures. The present work proposes a strategy to decouple the effect of ion exchange from topographical features by adjusting the volume ratio between the cell culture medium and biomaterial (V_CM/V_B). Increasing this ratio allowed mitigating the drastic ionic exchanges associated to the compositional changes experienced by the material exposed to the cell culture medium. This strategy was validated using rat mesenchymal stem cells (rMSCs) cultured on CDHA and beta-tricalcium phosphate (β-TCP) discs using different V_CM/V_B ratios. Whereas in the case of β-TCP the cell response was not affected by this ratio, a significant effect on cell adhesion and proliferation was found for the more reactive CDHA. The ionic exchange, produced by CDHA at low V_CM/V_B, altered cell adhesion due to the reduced number of focal adhesions, caused cell shrinkage and further rMCSs apoptosis. This was mitigated when using a high V_CM/V_B, which attenuated the changes of calcium and phosphate concentrations in the cell culture medium, resulting in rMSCs spreading and a viability over time. Moreover, rMSCs showed an earlier expression of osteogenic genes on CDHA compared to sintered β-TCP when extracellular calcium fluctuations were reduced.

STATEMENT OF SIGNIFICANCE

Fluid mediated interactions play a significant role in the bioactivity of calcium phosphates. Ionic exchange is amplified in the case of biomimetic hydroxyapatite, which makes the in vitro characterisation of cell-material interactions especially challenging. The present work proposes a novel and simple strategy to explore the mechanisms of interaction of biomimetic and sintered calcium phosphates with mesenchymal stem cells. The effects of topography and ion exchange are analysed separately by modifying the volume ratio between cell culture medium and biomaterial. High ionic fluctuations interfered in the maturation of focal adhesions, hampering cell adhesion and leading to increased apoptosis and reduced proliferation rate.

Berberine Attenuates Macrophages Infiltration in Intracranial Aneurysms Potentially Through FAK/Grp78/UPR Axis

Background: Inflammatory cells, such as macrophages, play key roles in the pathogenesis of intracranial aneurysms (IAs). Berberine (BBR), an active component of a Chinese herb Coptis chinensis French, has been shown to have anti-inflammatory properties through suppressing macrophage migration in various inflammation animal model. The goal of this study was to examine BBR’s effect on inflammation and IAs formation in a rodent aneurysm model.

Methods and Results: Human aneurysm tissues were collected by microsurgical clipping and immunostained for phospho-Focal adhesion kinase (FAK) and CD68⁺ macrophages. A rodent aneurysm model was induced in 5-week-old male Sprague Dawley (SD) rats by intracranial surgery, then these rats were orally administrated 200 mg/kg/day BBR for 35 days. Immunostaining data showed that BBR inhibited CD68⁺ macrophages accumulation in IAs tissues and suppressed FAK phosphorylation. In lipopolysaccharide (LPS)-stimulated RAW264.7 cells, BBR treatment remarkably attenuated macrophages infiltration, suppressed the expression of matrix metalloproteinases (MMPs), and reduced proinflammatory cytokine secretion, including MCP-1, interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor-a (TNF-α). Mechanistically, BBR downregulated FAK/Grp78/Unfolded Protein Response (UPR) signaling pathway in RAW264.7 cells.

Conclusion: BBR prevents IAs formation potentially through inhibiting FAK phosphorylation and inactivating UPR pathway in macrophages, which causes less macrophage infiltration and reduced proinflammatory cytokine release.

CADM2, as a new target of miR-10b, promotes tumor metastasis through FAK/AKT pathway in hepatocellular carcinoma

BACKGROUND

Cell adhesion molecules (CADMs) comprise of a protein family whose functions include maintenance of cell polarity and tumor suppression. Hypo-expression of CADM2 gene expression has been observed in several cancers including hepatocellular carcinoma (HCC). However, the role and mechanisms of CADM2 in HCC remain unclear.

METHODS

The expression of CADM2 and miRNA-10b (miR-10b) in HCC tissues and cell lines were detected using real-time PCR and Western blotting. Immunofluorescence was used to detect Epithelial-mesenchymal transition (EMT) progression in HCC cell lines. Dual-luciferase reporter assay was used to determine miR-10b binding to CADM2 3'UTR. Wound healing assay and Transwell assay were performed to examine the migration and invasion of HCC cells.

RESULTS

We report the effect of CADM2 as a tumor suppressor in HCC. Firstly, we confirmed that CADM2 expression was significantly down regulated in HCC tissues compared to normal tissues according to TCGA data analysis and fresh HCC sample detection. Secondly, overexpression of CADM2 could inhibit EMT process, migratory and invasion ability of HCC cells. Furthermore, the results indicated that CADM2 is a direct target of miR-10b in HCC cells and miR-10b/CADM2 modulates EMT process and migration ability via focal adhesion kinase (FAK) /AKT signaling pathway in HCC.

CONCLUSIONS

Our study demonstrates that miR-10b-CADM2-FAK/AKT axis plays an important role in HCC metastasis, which might be a novel potential therapeutic option for HCC treatment.

Homologous Sodium Alginate/Chitosan-Based Scaffolds, but Contrasting Effect on Stem Cell Shape and Osteogenesis

Stem cell shape appears to be involved in the regulation of osteogenesis, which has been confirmed in two-dimensional surfaces and three-dimensional hydrogels. The present study evaluated the effect of matrix-controlled cellular shape on osteogenesis in three-dimensional porous scaffolds based on sodium alginate (ALG) and chitosan (CS). Three ALG/CS scaffolds, especially including a stiff one, were fabricated from different precursor matrices. Soft scaffold A was fabricated from the ALG/CS polyelectrolyte and further cross-linked by Ca²⁺ and glutaraldehyde to achieve soft scaffold B with alternative hydrophilicity. Stiff scaffold C with "hard-to-deform" feature was fabricated from "ALG/CS preformed gel", which was an ALG gel network expanded by swelling force of the dissolving CS, and fixed using Ca²⁺ and glutaraldehyde. Scanning electron microscopy and F-actins staining showed rounded mesenchymal stem cells (MSCs) on the inner surfaces inside scaffold A with high swelling behavior, but spindlelike MSCs in scaffold B. Stiff scaffold C forced MSCs to adhere to polygonal shape. Fibronectin adsorption was found to be weakened in scaffold A. Integrin α5β1 expression, as well as osteogenesis-related genes (ALP, OCN) expression, was detected to be higher in the stiff scaffold C. Thus, the present study illustrated that the stiff scaffold C responded to cells with hard-to-deform information, leading to the amplification of focal adhesions and induction of high tension of cells, consequently enhancement of osteogenesis.

The promotion function of Berberine for osteogenic differentiation of human periodontal ligament stem cells via ERK-FOS pathway mediated by EGFR

Coptidis Rhizoma binds to the membrane receptors on hPDLSC/CMC, and the active ingredient Berberine (BER) that can be extracted from it may promote the proliferation and osteogenesis of periodontal ligament stem cells (hPDLSC). The membrane receptor that binds with BER on the cell surface of hPDLSC, the mechanism of direct interaction between BER and hPDLSC, and the related signal pathway are not yet clear. In this research, EGFR was screened as the affinity membrane receptor between BER and hPDLSC, through retention on CMC, competition with BER and by using a molecular docking simulation score. At the same time, the MAPK PCR Array was selected to screen the target genes that changed when hPDLSC was simulated by BER. In conclusion, BER may bind to EGFR on the cell membrane of hPDLSC so the intracellular ERK signalling pathways activate, and nuclear-related genes of FOS change, resulting in the effect of osteogenesis on PDLSC.

Collagen-Coated Poly(lactide-co-glycolide)/Hydroxyapatite Scaffold Incorporated with DGEA Peptide for Synergistic Repair of Skull Defect

The treatment of large-area bone defects remains a challenge; however, various strategies have been developed to improve the performances of scaffolds in bone tissue engineering. In this study, poly(lactide-co-glycolide)/hydroxyapatite (PLGA/HA) scaffold was coated with Asp-Gly-Glu-Ala (DGEA)-incorporated collagen for the repair of rat skull defect. Our results indicated that the mechanical strength and hydrophilicity of the PLGA/HA scaffold were clearly improved and conducive to cell adhesion and proliferation. The collagen-coated scaffold with DGEA significantly promoted the repair of skull defect. These findings indicated that a combination of collagen coating and DGEA improved scaffold properties for bone regeneration, thereby providing a new potential strategy for scaffold design.