Transforming growth factor-β1 (TGF-β1) is essential for cartilage regeneration, but its susceptibility to enzymatic denaturation and high cost limit its application. Herein, we report Ac-LIANAKGFEFEFKFK-NH₂ (LKP), a self-assembled peptide nanofiber hydrogel that can mimic the function of TGF-β1. The LKP hydrogel is simple to synthesize, and in vitro experiments confirmed its good biocompatibility and cartilage-promoting ability. However, LKP hydrogels suffer from poor mechanical properties and are prone to fragmentation; therefore, we prepared a series of injectable hydrogel composite scaffolds (SF-GMA/LKP) by combining LKP with glycidyl methacrylate (GMA)-modified silk fibroin (SF). SF-GMA/LKP composite scaffolds instantaneously induced in-situ filling of cartilage defects and, at the same time, relied on the interaction between LKP and SF-GMA interaction to prolong the duration of action of LKP. The SF-GMA/LKP10 and SF-GMA/LKP20 composite scaffolds had the best effect on neocartilage and subchondral bone reconstruction. This composite hydrogel scaffold can be used for high-quality cartilage repair.

Elevated glucose metabolism is a prominent characteristic of fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA). However, the efficacy of inhibiting a single target of glucose metabolism in FLS using small molecular inhibitors is limited for RA treatment. Herein, the synergistic inhibition of FLS’ survival, proliferation, and activation by combining two glucose metabolism inhibitors, diclofenac (DC) and lonidamine (LND) was first verified. Subsequently, DC and LND were individually conjugated to cystamine-modified hyaluronic acid (HA) to prepare two polymer-prodrug conjugates. A HAP-1 peptide-modified dual polymer-prodrug conjugates-assembled nanoparticles system (^HAP−1NP_DC+LND) was further tailored in the optimal synergistic ratio for targeted and synergistic metabolic modulation of FLS to alleviate RA symptoms. Upon targeted uptake by FLS in inflamed joints, ^HAP−1NP_DC+LND released DC and LND within the intracellular reductive microenvironment, where DC hinders glucose uptake and LND suppresses glycolytic enzymes to eliminate FLS synergistically. Additionally, the secretion of lactic acid and pro-inflammatory factors from FLS were reduced, thereby disrupting the crosstalk between FLS and pro-inflammatory macrophages. Finally, ^HAP−1NP_DC+LND demonstrated promising efficacy in a mouse model of collagen-induced arthritis (CIA). Overall, this research provides valuable insights into novel therapeutic strategies for the safe and effective of treatment RA through targeted and synergistic metabolic modulation of FLS.

Bone defects are challenging to treat in musculoskeletal system due to the lack of vascularization. Biomaterials with internal vascularization ability and osteoinduction bioactivity are promising strategies for orthopedic applications. Vascular endothelial growth factor (VEGF) has been widely used for angiogenesis and osteogenesis. Here, we developed VEGF-loaded PLGA microbubbles (MBs) for improvement of angiogenesis and osteogenesis in bone defect repair in combination with ultrasound-targeted microbubble destruction (UTMD). Release profile showed UTMD promoted the burst release of VEGF from PLGA MBs. We subsequently investigated the combination of ultrasound application with VEGF MBs for in vitro osteogenesis. The results demonstrated that the expression of osteogenesis-related genes and calcium deposits were increased by VEGF MBs in combination of UTMD. Micro-computed tomography (micro-CT) and histological analysis were conducted 4 and 8 weeks post-surgery. In vivo results show that VEGF MBs in combination of UTMD could significantly enhance new bone formation and vascular ingrowth at the defect site in a rat calvarial defect model. In summary, VEGF MBs in combination of UTMD could augment bone regeneration and vascularization at calvarial bone defects and hold huge potential for clinical translation.