Wogonin mitigates intervertebral disc degeneration through the Nrf2/ARE and MAPK signaling pathways.

Intervertebral disc degeneration (IVDD) is a prevalent disease characterized by the progressive loss of the extracellular matrix in the local nucleus pulposus region. Metalloproteinases and pro-inflammatory cytokines play an important role in this process. Thus, anti-inflammatory strategies are an important component of IVDD treatment. Wogonin, a naturally existing monoflavonoid, has been reported to have potential anti-inflammatory effects in some inflammatory diseases. Hence, in our present study we investigated the protective effects and potential mechanisms of wogonin in rat nucleus pulposus cells that had been treated with interleukin-1beta (IL-1ß) to induce severe IVDD. An in vivo rat caudal vertebrae needle-stab model was also designed and its validity was evaluated as an IVDD model. The results demonstrated that wogonin suppressed IL-1ß-induced inflammatory mediators (iNOS, IL-6 and COX2) and matrix-degrading proteinases (MMP1, MMP3, MMP13 and ADAMTS4). Wogonin also upregulated some of the key components of the extracellular matrix, such as collagen II. Furthermore, we discovered that wogonin exerted anti-inflammatory effects by activating the Nrf2/HO-1-SOD2-NQO1-GCLC signaling axis. Moreover, the IL-1ß-induced stimulation of the MAPK signaling pathway was reversed by wogonin treatment. The in vivo MRI and histological results also revealed that wogonin protected the nucleus pulposus from the progression of IVDD. Therefore, wogonin may be a potential agent for the treatment of IVDD.

Injectable decellularized nucleus pulposus-based cell delivery system for differentiation of adipose-derived stem cells and nucleus pulposus regeneration.

Stem cell-based tissue engineering is a promising treatment for intervertebral disc (IVD) degeneration. A bio-scaffold that can maintain the function of transplanted cells and possesses favorable mechanical properties is needed in tissue engineering. Decellularized nucleus pulposus (dNP) has the potential to be a suitable bio-scaffold because it mimics the native nucleus pulposus (NP) composition. However, matrix loss during decellularization and difficulty in transplantation limit the clinical application of dNP scaffolds. In this study, we fabricated an injectable dNP-based cell delivery system (NPCS) and evaluated its properties by assessing the microstructure, biochemical composition, water content, biosafety, biostability, and mechanical properties. We also investigated the stimulatory effects of the bio-scaffold on the NP-like differentiation of adipose-derived stem cells (ADSCs) in vitro and the regenerative effects of the NPCS on degenerated NP in an in vivo animal model. The results showed that approximately 68% and 43% of the collagen and sGAG, respectively, remained in the NPCS after 30 days. The NPCS also showed mechanical properties similar to those of fresh NP. In addition, the NPCS was biocompatible and able to induce NP-like differentiation and extracellular matrix (ECM) synthesis in ADSCs. The disc height index (almost 81%) and the MRI index (349.05 ±â€¯38.48) of the NPCS-treated NP were significantly higher than those of the degenerated NP after 16 weeks. The NPCS also partly restored the ECM content and the structure of degenerated NP in vivo. Our NPCS has good biological and mechanical properties and has the ability to promote the regeneration of degenerated NP. STATEMENT OF SIGNIFICANCE: Nucleus pulposus (NP) degeneration is usually the origin of intervertebral disc degeneration. Stem cell-based tissue engineering is a promising treatment for NP regeneration. Bio-scaffolds which have favorable biological and mechanical properties are needed in tissue engineering. Decellularized NP (dNP) scaffold is a potential choice for tissue engineering, but the difficulty in balancing complete decellularization and retaining ECM limits its usage. Instead of choosing different decellularization protocols, we complementing the sGAG lost during decellularization by cross-linking via genipin and fabricating an injectable dNP-based cell delivery system (NPCS) which has similar components as the native NP. We also investigated the biological and mechanical properties of the NPCS in vitro and verified its regenerative effects on degenerated IVDs in an animal model.

Genipin cross-linked type II collagen/chondroitin sulfate composite hydrogel-like cell delivery system induces differentiation of adipose-derived stem cells and regenerates degenerated nucleus pulposus.

Nucleus pulposus (NP) degeneration is usually the origin of intervertebral disc degeneration and consequent lower back pain. Although adipose-derived stem cell (ADSC)-based therapy is regarded to be promising for the treatment of degenerated NP, there is a lack of viable cell carriers to transplant ADSCs into the NP while maintaining cell function. In this study, we developed a type II collagen/chondroitin sulfate (CS) composite hydrogel-like ADSC (CCSA) delivery system with genipin as the cross-linking agent. The induction effect of the scaffold on ADSC differentiation was studied in vitro, and a rat coccygeal vertebrae degeneration model was used to investigate the regenerative effect of the CCSA system on the degenerated NP in vivo. The results showed that the CCSA delivery system cross-linked with 0.02% genipin was biocompatible and promoted the expressions of NP-specific genes. After the injection of the CCSA system, the disc height, water content, extracellular matrix synthesis, and structure of the degenerated NP were partly restored. Our CCSA delivery system uses minimally invasive approaches to promote the regeneration of degenerated NP and provides an exciting new avenue for the treatment of degenerative disc disease. STATEMENT OF SIGNIFICANCE: Nucleus pulposus (NP) degeneration is usually the origin of intervertebral disc degeneration and consequent lower back pain. Stem cell-based tissue engineering is a promising method in NP regeneration, but there is a lack of viable cell carriers to transplant ADSCs into the NP while maintaining cell function. In this study, we developed a type II collagen/chondroitin sulfate (CS) composite hydrogel-like ADSC (CCSA) delivery system with genipin as the cross-linking agent. Although several research groups have studied the fabrication of injectable hydrogel with biological matrix, our study differs from other works. We chose type II collagen and CS, the two primary native components in the NP, as the main materials and combined them according to the natural ratio of collagen and sGAG in the NP. The delivery system is preloaded with ADSCs and can be injected into the NP with a needle, followed by in situ gelation. Genipin is used as a cross-linker to improve the bio-stability of the scaffold, with low cytotoxicity. We investigated the stimulatory effects of our scaffold on the differentiation of ADSCs in vitro and the regenerative effect of the CCSA delivery system on degenerated NP in vivo.

Genipin-cross-linked type II collagen scaffold promotes the differentiation of adipose-derived stem cells into nucleus pulposus-like cells.

Adipose-derived stem cells (ADSCs)-based tissue engineering was a promising method to treat intervertebral disc degeneration. Type II collagen is a native component in the nucleus pulposus (NP), and has the ability to promote ADSCs to differentiate into NP-like cells. In this article, we aimed to establish a genipin-cross-linked three-dimensional (3D) type II collagen scaffold, and determine the biological effects of the scaffold on ADSCs differentiating into a NP-like phenotype. Different concentrations of genipin were used to cross-link the 3D type II collagen scaffold. Microstructure, surface topography, mechanical strength, porosity, swelling property, and biological stability of the scaffolds were detected to evaluate the scaffold properties. Cell proliferation, gene and protein expression were measured to access the biological effects of the scaffolds on ADSCs, and the related molecular mechanism was investigated. Cross-linking by genipin increased the stability of the type II collagen scaffolds, but deformed the configuration of scaffolds and changed the intrinsic properties of type II collagen. scaffold cross-linked with 0.1% genipin improved the biostability on the basis of maintaining the configuration of scaffold. In addition, the 0.1% genipin-cross-linked scaffold promoted ADSCs proliferation and differentiation into NP-like cells, along with the increasing gene and protein expressions of Sonic Hedgehog (Shh). All these results suggested that 0.1% genipin was the optimal concentration to establish a bio-stable 3D type II collagen scaffold, which inducing ADSC proliferation and differentiation toward a NP-like phenotype through the activation of Shh signaling pathway. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1258-1268, 2018.

Escin induces caspase-dependent apoptosis and autophagy through the ROS/p38 MAPK signalling pathway in human osteosarcoma cells in vitro and in vivo.

Osteosarcoma is one of the most malignant neoplasms in adolescents, and it generally develops multidrug resistance. Escin, a natural mixture of triterpene saponins isolated from Aesculus hippocastanum (horse chestnut), has demonstrated potent anti-tumour potential in vitro and in vivo. In the present study, we found that escin inhibited osteosarcoma proliferation in a dose- and time-dependent manner. Additionally, escin-induced apoptosis was evidenced by the increased expression of caspase-related proteins and the formation of apoptotic bodies. Escin also induced autophagy, with elevated LC3, ATG5, ATG12 and Beclin expression as well as autophagosome formation. Inhibition of escin-induced autophagy promoted apoptosis. Moreover, p38 mitogen-activated protein kinases (MAPKs) and reactive oxygen species (ROS) were activated by escin. A p38 MAPK inhibitor partially attenuated the autophagy and apoptosis triggered by escin, but a ROS scavenger showed a greater inhibitory effect. Finally, the therapeutic efficacy of escin against osteosarcoma was demonstrated in an orthotopic model. Overall, escin counteracted osteosarcoma by inducing autophagy and apoptosis via the activation of the ROS/p38 MAPK signalling pathway; these findings provide evidence for escin as a novel and potent therapeutic for the treatment of osteosarcoma.

A review and outlook in the treatment of osteosarcoma and other deep tumors with photodynamic therapy: from basic to deep.

Photodynamic therapy, one of the most promising minimally invasive treatments, has received increasing focus in tumor therapy research, which has been widely applied in treating superficial tumors. Three basic factors - photosensitizer, the light source, and oxidative stress - are responsible for tumor cell cytotoxicity. However, due to insufficient luminous flux and peripheral tissue damage, the utilization of photodynamic therapy is facing a huge limitation in deep tumor therapy. Osteosarcoma is the typical deep tumor, which is the most commonly occurring malignancy in children and adolescents. Despite developments in surgery, high risks of the amputation still threatens the health of osteosarcoma patients. In this review, we summarize recent developments in the field of photodynamic therapy and specifically PDT research in OS treatment modalities. In addition, we also provide some novel suggestions, which could potentially be a breakthrough in PDT-induced OS therapies. PDT has the potential to become an effective therapy while the its limitations still present when applied on the treatment of OS or other types of deep tumors. Thus, more researches and studies in the field are required.