Background Targeting PLK1 has recently been proven as a viable therapeutic strategy against oesophageal squamous cell carcinom (ESCC). Therefore, this study aimed to explore whether the PLK1 inhibitor BI2536 is able to sensitize ESCC cells to cisplatin (DDP) and determine the underlying mechanisms. Methods Viability, clonogenicity, cell cycle distribution and apoptosis were assessed in ESCC cells treated with BI2536 or DDP alone or in combination. Checkpoint activation was examined by immunoblotting and immunohistochemistry. Xenograft model was used to assess the efficacy of the co-treatment. The expression level of GSDME in tissue samples were examined by immunohistochemistry. Findings We found that the combination of BI2536 and DDP was synergistic in ESCC cells, which induced pyroptosis in ESCC cells at low doses. Mechanistic studies revealed that BI2536 significantly induced DNA damage and impaired the DNA damage repair pathway in DDP-treated cells both in vitro and in vivo . Interestingly, we found that co-treatment with BI2536 and DDP induced pyroptosis in ESCC cells depending on the caspase-3/GSDME pathway. Importantly, our study found that GSDME was more highly expressed in tumour tissue than that in normal adjacent tissues, and could serve as a prognostic factor. Interpretation BI2536 sensitizes ESCC cells to DDP by inhibiting the DNA damage repair pathway and inducing pyroptosis, which provides new information for understanding pyroptosis. Our study also reveals that the PLK1 inhibitor BI2536 may be an attractive candidate for ESCC targeted therapy, especially when combined with DDP for treating the GSDME overexpression subtype. Fund National 973 Program and National Natural Science Fundation of China.

At present, repair methods for peripheral nerve injury often fail to get satisfactory result. Although various strategies have been adopted to investigate the microenvironment after peripheral nerve injury, the underlying molecular mechanisms of neurite outgrowth remain unclear. In this study, we evaluate the effects of exosomes from gingival mesenchymal stem cells (GMSCs) combined with biodegradable chitin conduits on peripheral nerve regeneration. GMSCs were isolated from human gingival tissue and characterized by surface antigen analysis and in vitro multipotent differentiation. The cell supernatant was collected to isolate the exosomes. The exosomes were characterized by transmission electron microscopy, Western blot, and size distribution analysis. The effects of exosomes on peripheral nerve regeneration in vitro were evaluated by coculture with Schwann cells and DRGs. The chitin conduit was prepared and combined with the exosomes to repair rat sciatic nerve defect. Histology, electrophysiology, and gait analysis were used to test the effects of exosomes on sciatic nerve function recovery in vivo. We have successfully cultured GMSCs and isolated exosomes. The exosomes from GMSCs could significantly promote Schwann cell proliferation and DRG axon growth. The in vivo studies showed that chitin conduit combined with exosomes from GMSCs could significantly increase the number and diameter of nerve fibers and promote myelin formation. In addition, muscle function, nerve conduction function, and motor function were also obviously recovered. In summary, this study suggests that GMSC-derived exosomes combined with biodegradable chitin conduits are a useful and novel therapeutic intervention in peripheral nerve repair.

Various artificial materials have been fabricated as alternatives to autologous nerve grafts in peripheral nerve regeneration, and these afford positive recovery effects without the disadvantages of the gold standard. In this study, we prepared a three-dimensional functionalized self-assembling peptide nanofiber hydrogel containing two neurotrophic peptides (CTDIKGKCTGACDGKQC and RGIDKRHWNSQ derived from nerve growth factor and brain-derived neurotrophic factor, respectively) that reflected the structure and properties of the neural extracellular matrix. The material was used to promote axonal regrowth and functional recovery. Scanning electron microscopy revealed a three-dimensional porous matrix within the hydrogel. Circular dichroism spectroscopy and atomic force microscopy confirmed that the peptides displayed a β-sheet structure and self-assembled into long nanofibers. Rheology measurements and atomic force microscopy indicated that the elasticity of the peptide hydrogels was close to that of the nerve tissue matrix. In vitro work with Schwann cells and dorsal root ganglia showed that the hydrogels exhibited good cell compatibility. Furthermore, the hydrogel containing CTDIKGKCTGACDGKQC and RGIDKRHWNSQ promoted the neurite outgrowth of PC12 cells significantly compared to non-functionalized peptide. In vivo, the hydrogels were placed into chitosan tubes and used to bridge 10 mm long sciatic nerve defects in rats. We found that the combination of CTDIKGKCTGACDGKQC and RGIDKRHWNSQ accelerated axonal regeneration and afforded good functional recovery, suggesting that they synergistically facilitate peripheral nerve regeneration.

BackgroundArticular cartilage defects are difficult to treat, but drug-loaded tissue engineering scaffolds provide a possible treatment option for these types of injuries.PurposeIn this study, we designed a bioactive resveratrol–PLA–gelatin porous nano-scaffold using electrospinning, freeze drying, and uniform dispersion techniques to repair articular cartilage defects, and then investigated the possible mechanism behind the successful repair.MethodsWe established an articular cartilage defect rat model with a 2 mm diameter wound in the middle of the knee joint femoral condyle non-weight-bearing area, with a depth reaching the full thickness of the subchondral bone. Postmodel specimens and micro computed tomography (CT) were used to observe any macroscopic morphological changes in the articular cartilage and subchondral bone, whereas multiple staining methods were used to observe all microcosmic morphological changes. Gross scores and Mankin scores were used to evaluate the repair condition. Immunohistochemical staining was employed to detect protein expression.ResultsWhen the repair included the resveratrol–PLA–gelatin porous nano-scaffold, the repaired cartilage and subchondral bone were in better condition. The expression levels of SIRT1, type II collagen, and PI3K/AKT signaling pathway-related proteins (AKT, VEGF, PTEN, Caspase 9, and MMP13) changed significantly. The expression levels of SIRT1,AKT and type II collagen proteins increased significantly, while the expression levels of VEGF, PTEN, Caspase9 and MMP13 proteins decreased significantly compared with the repair included blank porous PLA–gelatin nano-scaffold and without scaffold.ConclusionWe designed a bioactive resveratrol–PLA–gelatin porous nano-scaffold with better performance, which promoted the repair of cartilage injury as a whole, and explained its possible mechanism in accelerating cartilage repair via the PI3K/AKT signaling pathway.

Cartilage defect is common in clinical but notoriously difficult to treat for low regenerative and migratory capacity of chondrocytes. Biodegradable tissue engineering nano-scaffold with a lot of advantages has been the direction of material to repair cartilage defect in recent years. The objective of our study is to establish a biodegradable drug-loading synthetic polymer (PLA) and biopolymer (Gelatine) composite 3D nano-scaffold to support the treatment of cartilage defect. We designed a microfluidic chip-based drug-screening device to select the optimum concentration of resveratrol, which has strong protective capability for chondrocyte. Then biodegradable resveratrol-loading PLA/Gelatine 3D nano-scaffolds were fabricated and used to repair the cartilage defects. As a result, we successfully cultured primary chondrocytes and screened the appropriate concentrations of resveratrol by the microfluidic device. We also smoothly obtained superior biodegradable resveratrol-loading PLA/Gelatine 3D nano-scaffolds and compared the properties and therapeutic effects of cartilage defect in rats. In summary, our microfluidic device is a simple but efficient platform for drug screening and resveratrol-loading PLA/Gelatine 3D nano-scaffolds could greatly promote the cartilage formation. It would be possible for materials and medical researchers to explore individualized pharmacotherapy and drug-loading synthetic polymer and biopolymer composite tissue engineering scaffolds for the repair of cartilage defect in future.