Malvidin attenuates trauma-induced heterotopic ossification of tendon in rats by targeting Rheb for degradation via the ubiquitin-proteasome pathway.

The pathogenesis of trauma-induced heterotopic ossification (HO) in the tendon remains unclear, posing a challenging hurdle in treatment. Recognizing inflammation as the root cause of HO, anti-inflammatory agents hold promise for its management. Malvidin (MA), possessing anti-inflammatory properties, emerges as a potential agent to impede HO progression. This study aimed to investigate the effect of MA in treating trauma-induced HO and unravel its underlying mechanisms. Herein, the effectiveness of MA in preventing HO formation was assessed through local injection in a rat model. The potential mechanism underlying MA's treatment was investigated in the tendon-resident progenitor cells of tendon-derived stem cells (TDSCs), exploring its pathway in HO formation. The findings demonstrated that MA effectively hindered the osteogenic differentiation of TDSCs by inhibiting the mTORC1 signalling pathway, consequently impeding the progression of trauma-induced HO of Achilles tendon in rats. Specifically, MA facilitated the degradation of Rheb through the K48-linked ubiquitination-proteasome pathway by modulating USP4 and intercepted the interaction between Rheb and the mTORC1 complex, thus inhibiting the mTORC1 signalling pathway. Hence, MA presents itself as a promising candidate for treating trauma-induced HO in the Achilles tendon, acting by targeting Rheb for degradation through the ubiquitin-proteasome pathway.

Bimodal DNA self-origami material with nucleic acid function enhancement.

BACKGROUND: The design of DNA materials with specific nanostructures for biomedical tissue engineering applications remains a challenge. High-dimensional DNA nanomaterials are difficult to prepare and are unstable; moreover, their synthesis relies on heavy metal ions. Herein, we developed a bimodal DNA self-origami material with good biocompatibility and differing functions using a simple synthesis method. We simulated and characterized this material using a combination of oxDNA, freeze-fracture electron microscopy, and atomic force microscopy. Subsequently, we optimized the synthesis procedure to fix the morphology of this material. RESULTS: Using molecular dynamics simulation, we found that the bimodal DNA self-origami material exhibited properties of spontaneous stretching and curling and could be fixed in a single morphology via synthesis control. The application of different functional nucleic acids enabled the achievement of various biological functions, and the performance of functional nucleic acids was significantly enhanced in the material. Consequently, leveraging the various functional nucleic acids enhanced by this material will facilitate the attainment of diverse biological functions. CONCLUSION: The developed design can comprehensively reveal the morphology and dynamics of DNA materials. We thus report a novel strategy for the construction of high-dimensional DNA materials and the application of functional nucleic acid-enhancing materials.

Hydrogel composite scaffolds achieve recruitment and chondrogenesis in cartilage tissue engineering applications.

BACKGROUND: The regeneration and repair of articular cartilage remains a major challenge for clinicians and scientists due to the poor intrinsic healing of this tissue. Since cartilage injuries are often clinically irregular, tissue-engineered scaffolds that can be easily molded to fill cartilage defects of any shape that fit tightly into the host cartilage are needed. METHOD: In this study, bone marrow mesenchymal stem cell (BMSC) affinity peptide sequence PFSSTKT (PFS)-modified chondrocyte extracellular matrix (ECM) particles combined with GelMA hydrogel were constructed. RESULTS: In vitro experiments showed that the pore size and porosity of the solid-supported composite scaffolds were appropriate and that the scaffolds provided a three-dimensional microenvironment supporting cell adhesion, proliferation and chondrogenic differentiation. In vitro experiments also showed that GelMA/ECM-PFS could regulate the migration of rabbit BMSCs. Two weeks after implantation in vivo, the GelMA/ECM-PFS functional scaffold system promoted the recruitment of endogenous mesenchymal stem cells from the defect site. GelMA/ECM-PFS achieved successful hyaline cartilage repair in rabbits in vivo, while the control treatment mostly resulted in fibrous tissue repair. CONCLUSION: This combination of endogenous cell recruitment and chondrogenesis is an ideal strategy for repairing irregular cartilage defects.

Cartilage lacuna-biomimetic hydrogel microspheres endowed with integrated biological signal boost endogenous articular cartilage regeneration.

Despite numerous studies on chondrogenesis, the repair of cartilage-particularly the reconstruction of cartilage lacunae through an all-in-one advanced drug delivery system remains limited. In this study, we developed a cartilage lacuna-like hydrogel microsphere system endowed with integrated biological signals, enabling sequential immunomodulation and endogenous articular cartilage regeneration. We first integrated the chondrogenic growth factor transforming growth factor-ß3 (TGF-ß3) into mesoporous silica nanoparticles (MSNs). Then, TGF-ß3@MSNs and insulin-like growth factor 1 (IGF-1) were encapsulated within microspheres made of polydopamine (pDA). In the final step, growth factor-loaded MSN@pDA and a chitosan (CS) hydrogel containing platelet-derived growth factor-BB (PDGF-BB) were blended to produce growth factors loaded composite microspheres (GFs@µS) using microfluidic technology. The presence of pDA reduced the initial acute inflammatory response, and the early, robust release of PDGF-BB aided in attracting endogenous stem cells. Over the subsequent weeks, the continuous release of IGF-1 and TGF-ß3 amplified chondrogenesis and matrix formation. µS were incorporated into an acellular cartilage extracellular matrix (ACECM) and combined with a polydopamine-modified polycaprolactone (PCL) structure to produce a tissue-engineered scaffold that mimicked the structure of the cartilage lacunae evenly distributed in the cartilage matrix, resulting in enhanced cartilage repair and patellar cartilage protection. This research provides a strategic pathway for optimizing growth factor delivery and ensuring prolonged microenvironmental remodeling, leading to efficient articular cartilage regeneration.

Eupalinolide A attenuates trauma-induced heterotopic ossification of tendon in mice by promoting YAP degradation through TOLLIP-mediated selective autophagy.

BACKGROUND: Inhibiting the aberrant osteogenic differentiation of tendon-derived stem cells (TDSCs) is an effective strategy for treating traumatic heterotopic ossification (HO) in tendons. PURPOSE: This study aimed to investigate whether eupalinolide A (EA) could prevent tendon HO progression by suppressing the osteogenic differentiation of TDSCs. METHODS: The effects of EA on osteogenic differentiation and key signaling pathways in TDSCs were examined in vitro to assess its therapeutic potential and elucidate the underlying molecular mechanisms. Furthermore, the therapeutic efficacy of EA was evaluated in a mouse model of trauma-induced tendon HO via local injection therapy. RESULTS: EA significantly inhibited the osteogenic differentiation of TDSCs by targeting YAP in vitro. Specifically, EA facilitated the recruitment of E3 ubiquitin ligase HECW1, which mediated K27-linked polyubiquitination of YAP, leading to its degradation via the TOLLIP-mediated selective autophagy pathway. In vivo, EA mitigated trauma-induced tendon HO by inhibiting the YAP pathway. CONCLUSIONS: EA could be a potential therapeutic agent for treating traumatic tendon HO. The therapeutic target HECW1 involved in YAP degradation via autophagy presents a new therapeutic avenue to attenuate the progression of traumatic tendon HO.

Combination of a human articular cartilage-derived extracellular matrix scaffold and microfracture techniques for cartilage regeneration: A proof of concept in a sheep model.

Background: The utilization of decellularized extracellular matrix has gained considerable attention across numerous areas in regenerative research. Of particular interest is the human articular cartilage-derived extracellular matrix (hACECM), which presents as a promising facilitator for cartilage regeneration. Concurrently, the microfracture (MF) â€‹technique, a well-established marrow stimulation method, has proven efficacious in the repair of cartilage defects. However, as of the current literature review, no investigations have explored the potential of a combined application of hACECM and the microfracture technique in the repair of cartilage defects within a sheep model. Hypothesis: The combination of hACECM scaffold and microfracture will result in improved repair of full-thickness femoral condyle articular cartilage defects compared to the use of either technique alone. Study design: Controlled laboratory study. Methods: Full-thickness femoral condyle articular cartilage defect (diameter, 7.0 â€‹mm; debrided down to the subchondral bone plate) were created in the weight-bearing area of the femoral medial and lateral condyles (n â€‹= â€‹24). All of defected sheep were randomly divided into four groups: control, microfracture, hACECM scaffold, and hACECM scaffold â€‹+ â€‹microfracture. After 3, 6 and 12 months, the chondral repair was assessed for standardized (semi-) quantitative macroscopic, imaging, histological, immunohistochemical, mechanics, and biochemical analyses in each group. Result: At 3, 6 and 12 months after implantation, the gross view and pathological staining of regenerative tissues were better in the hACECM scaffold and hACECM scaffold â€‹+ â€‹microfracture groups than in the microfracture and control groups; Micro-CT result showed that the parameters about the calcified layer of cartilage and subchondral bone were better in the hACECM scaffold and hACECM scaffold â€‹+ â€‹microfracture groups than the others, and excessive subchondral bone proliferation in the microfracture group. The results demonstrate that human cartilage extracellular matrix scaffold alone is an efficient, safe and simple way to repair cartilage defects. Conclusion: hACECM scaffolds combined with/without microfracture facilitate chondral defect repair. The translational potential of this article: Preclinical large animal models represent an important adjunct and surrogate for studies on articular cartilage repair, while the sheep stifle joint reflects many key features of the human knee and are therefore optimal experimental model for future clinical application in human. In this study, we developed a human articular cartilage-derived extracellular matrix scaffold and to verify the viability of its use in sheep animal models. Clinical studies are warranted to further quantify the effects of hACECM scaffolds in similar settings.

Carpaine alleviates tendinopathy in mice by promoting the ubiquitin-proteasomal degradation of p65 via targeting the E3 ubiquitin ligase LRSAM1.

BACKGROUND: Currently, there are no specific drugs or targets available for the treatment of tendinopathy. However, inflammation has recently been found to play a pivotal role in tendinopathy progression, thereby identifying it as a potential therapeutic target. Carpaine (CA) exhibits potential anti-inflammatory pharmacological properties and may offer a therapeutic option for tendinopathy. PURPOSE: This study aimed to investigate the effectiveness of CA in addressing tendinopathy and uncovering its underlying mechanisms. METHODS: Herein, the efficacy of CA by local administration in vivo in comparison to the first-line drug indomethacin was evaluated in a mouse collagenase-induced tendinopathy (CIT) model. Furthermore, IL-1ß induced a simulated pathological inflammatory microenvironment in tenocytes to investigate its underlying mechanisms in vitro. Further confirmation experiments were performed by overexpressing or knocking down the selective targets of CA in vivo. RESULTS: The findings demonstrated that CA was dose-dependent in treating tendinopathy and that the high-dose group outperformed the first-line drug indomethacin. Mechanistically, CA selectively bound to and enhanced the activity of the E3 ubiquitin ligase LRSAM1 in tendinopathy. This effect mediated the ubiquitination of p65 at lysine 93, subsequently promoting its proteasomal degradation. As a result, the NF-κB pathway was inactivated, leading to a reduction in inflammation of tendinopathy. Consequently, CA effectively mitigated the progression of tendinopathy. Moreover, the LRSAM1 overexpression demonstrated effectiveness in mitigating the tendinopathy progression and its knockdown abolished the therapeutic effects of CA. CONCLUSION: CA attenuates the progression of tendinopathy by promoting the ubiquitin-proteasomal degradation of p65 via increasing the enzyme activity of LRSAM1. The exploration of LRSAM1 has also unveiled a new potential target for treating tendinopathy based on the ubiquitin-proteasomal pathway.

The direct catalytic synthesis of ultrasmall Cu2O-coordinated carbon nitrides on ceria for multimodal antitumor therapy.

Engineering chem-/sono-/photo-multimodal antitumor therapies has become an efficient strategy to combat malignant tumors. However, the existence of hypoxia in the tumor microenvironment (TME) leads to limited sonodynamic or photodynamic efficiency because O2 is the key reactant during the process of generation of reactive oxygen species (ROS). Here, to design a desirable platform that can simultaneously convert H2O2 in the TME into ROS and O2 for efficient chem-/sono-/photo-multimodal tumor therapies, we have created ultrasmall Cu2O-coordinated carbon nitride on a biocompatible ceria substrate (denoted as Cu2O-CNx@CeO2) via a self-assisted catalytic growth strategy. The chemical and morphological structures, ROS and O2 generation activities, and chemo-/photo-/sono-dynamic specificities of Cu2O-CNx@CeO2 when serving as multifunctional biocatalytic agents were systematically disclosed. The experimental studies validated that Cu2O-CNx@CeO2 presents state-of-the-art peroxidase-like and catalase-like activities. Moreover, the light excitation and ultrasound irradiation were also demonstrated to boost ROS production. The in vitro and in vivo experiments suggest that Cu2O-CNx@CeO2 can efficiently inhibit the growth of malignant melanoma via chem-/sono-/photo-multimodal antitumor ability. We believe that applying these new biocatalysts with dual catalytic activities of producing ROS and O2 will offer a new path for engineering multimodal nanoagents to combat malignant tumors.

Multifaceted Catalytic ROS-Scavenging via Electronic Modulated Metal Oxides for Regulating Stem Cell Fate.

Developing reactive oxygen species (ROS)-scavenging nanostructures to protect and regulate stem cells has emerged as an intriguing strategy for promoting tissue regeneration, especially in trauma microenvironments or refractory wounds. Here, an electronic modulated metal oxide is developed via Mn atom substitutions in Co3 O4 nanocrystalline (Mn-Co3 O4 ) for highly efficient and multifaceted catalytic ROS-scavenging to reverse the fates of mesenchymal stem cells (MSCs) in oxidative-stress microenvironments. Benefiting from the atomic Mn-substitution and charge transfer from Mn to Co, the Co site in Mn-Co3 O4 displays an increased ratio of Co2+ /Co3+ and improved redox properties, thus enhancing its intrinsic and broad-spectrum catalytic ROS-scavenging activities, which surpasses most of the currently reported metal oxides. Consequently, the Mn-Co3 O4 can efficiently protect the MSCs from ROS attack and rescue their functions, including adhesion, spreading, proliferation, and osteogenic differentiation. This work not only establishes an efficient material for catalytic ROS-scavenging in stem-cell-based therapeutics but also provides a new avenue to design biocatalytic metal oxides via modulation of electronic structure.

Hierarchical macro-microporous WPU-ECM scaffolds combined with Microfracture Promote in Situ Articular Cartilage Regeneration in Rabbits.

Tissue engineering provides a promising avenue for treating cartilage defects. However, great challenges remain in the development of structurally and functionally optimized scaffolds for cartilage repair and regeneration. In this study, decellularized cartilage extracellular matrix (ECM) and waterborne polyurethane (WPU) were employed to construct WPU and WPU-ECM scaffolds by water-based 3D printing using low-temperature deposition manufacturing (LDM) system, which combines rapid deposition manufacturing with phase separation techniques. The scaffolds successfully achieved hierarchical macro-microporous structures. After adding ECM, WPU scaffolds were markedly optimized in terms of porosity, hydrophilia and bioactive components. Moreover, the optimized WPU-ECM scaffolds were found to be more suitable for cell distribution, adhesion, and proliferation than the WPU scaffolds. Most importantly, the WPU-ECM scaffold could facilitate the production of glycosaminoglycan (GAG) and collagen and the upregulation of cartilage-specific genes. These results indicated that the WPU-ECM scaffold with hierarchical macro-microporous structures could recreate a favorable microenvironment for cell adhesion, proliferation, differentiation, and ECM production. In vivo studies further revealed that the hierarchical macro-microporous WPU-ECM scaffold combined with the microfracture procedure successfully regenerated hyaline cartilage in a rabbit model. Six months after implantation, the repaired cartilage showed a similar histological structure and mechanical performance to that of normal cartilage. In conclusion, the hierarchical macro-microporous WPU-ECM scaffold may be a promising candidate for cartilage tissue engineering applications in the future.