Hepatocellular carcinoma (HCC) is a highly heterogeneous disease, which makes the prognostic prediction challenging. Ferroptosis, an iron-dependent form of regulated cell death, can be induced by sorafenib. However, the prognostic value of ferroptosis-related genes in HCC remains to be further elucidated. In this study, the mRNA expression profiles and corresponding clinical data of HCC patients were downloaded from public databases. The least absolute shrinkage and selection operator (LASSO) Cox regression model was utilized to construct a multigene signature in the TCGA cohort. HCC patients from the ICGC cohort were used for validation. Our results showed that most of the ferroptosis-related genes (81.7%) were differentially expressed between HCC and adjacent normal tissues in the TCGA cohort. Twenty-six differentially expressed genes (DEGs) were correlated with overall survival (OS) in the univariate Cox regression analysis (all adjusted P< 0.05). A 10-gene signature was constructed to stratify patients into two risk groups. Patients in the high-risk group showed significantly reduced OS compared with patients in the low-risk group (P < 0.001 in the TCGA cohort and P = 0.001 in the ICGC cohort). The risk score was an independent predictor for OS in multivariate Cox regression analyses (HR> 1, P< 0.01). Receiver operating characteristic (ROC) curve analysis confirmed the signature's predictive capacity. Functional analysis revealed that immune-related pathways were enriched, and immune status were different between two risk groups. In conclusion, a novel ferroptosis-related gene signature can be used for prognostic prediction in HCC. Targeting ferroptosis may be a therapeutic alternative for HCC.

Mimicking soft tissue mechanical properties and the high conductivity required for electrical transmission in the native spinal cord is critical in nerve tissue regeneration scaffold designs. However, fabricating scaffolds of high conductivity, tissue-like mechanical properties, and excellent biocompatibility simultaneously remains a great challenge. Here, a soft, highly conductive, biocompatible conducting polymer hydrogel (CPH) based on a plant-derived polyphenol, tannic acid (TA), cross-linking and doping conducting polypyrrole (PPy) chains is developed to explore its therapeutic efficacy after a spinal cord injury (SCI). The developed hydrogels exhibit an excellent electronic conductivity (0.05–0.18 S/cm) and appropriate mechanical properties (0.3–2.2 kPa), which can be achieved by controlling TA concentration. In vitro, a CPH with a higher conductivity accelerated the differentiation of neural stem cells (NSCs) into neurons while suppressing the development of astrocytes. In vivo, with relatively high conductivity, the CPH can activate endogenous NSC neurogenesis in the lesion area, resulting in significant recovery of locomotor function. Overall, our findings evidence that the CPHs without being combined with any other therapeutic agents have stimulated tissue repair following an SCI and thus have important implications for future biomaterial designs for SCI therapy.

Electroconductive hydrogels are very attractive candidates for accelerated spinal cord injury (SCI) repair because they match the electrical and mechanical properties of neural tissue. However, electroconductive hydrogel implantation can potentially aggravate inflammation, and hinder its repair efficacy. Bone marrow stem cell‐derived exosomes (BMSC‐exosomes) have shown immunomodulatory and tissue regeneration effects, therefore, neural tissue‐like electroconductive hydrogels loaded with BMSC‐exosomes are developed for the synergistic treatment of SCI. These exosomes‐loaded electroconductive hydrogels modulate microglial M2 polarization via the NF‐κB pathway, and synergistically enhance neuronal and oligodendrocyte differentiation of neural stem cells (NSCs) while inhibiting astrocyte differentiation, and also increase axon outgrowth via the PTEN/PI3K/AKT/mTOR pathway. Furthermore, exosomes combined electroconductive hydrogels significantly decrease the number of CD68‐positive microglia, enhance local NSCs recruitment, and promote neuronal and axonal regeneration, resulting in significant functional recovery at the early stage in an SCI mouse model. Hence, the findings of this study demonstrate that the combination of electroconductive hydrogels and BMSC‐exosomes is a promising therapeutic strategy for SCI repair.

Current treatment approaches for spinal cord injuries (SCIs) are mainly based on cellular transplantation. Induced pluripotent stem cells (iPSCs) without supply constraints and ethical concerns have emerged as a viable treatment option for repairing neurological disorders. However, the primarily limitations in the neuroregeneration field are uncontrolled cell differentiation, and low cell viability caused by the ischemic environment. The mechanical property of three-dimensional (3D) hydrogel can be easily controlled and shared similar characteristics with nerve tissue, thus promoting cell survival and controlled cell differentiation. We propose the combination of a 3D gelatin methacrylate (GelMA) hydrogel with iPSC-derived NSCs (iNSCs) to promote regeneration after SCI. In vitro, the iNSCs photoencapsulated in the 3D GelMA hydrogel survived and differentiated well, especially in lower-moduli hydrogels. More robust neurite outgrowth and more neuronal differentiation were detected in the soft hydrogel group. To further evaluate the in vivo neuronal regeneration effect of the GelMA hydrogels, a mouse spinal cord transection model was generated. We found that GelMA/iNSC implants significantly promoted functional recovery. Further histological analysis showed that the cavity areas were significantly reduced, and less collagen was deposited in the GelMA/iNSC group. Furthermore, the GelMA and iNSC combined transplantation decreased inflammation by reducing activated macrophages/microglia (CD68-positive cells). Additionally, GelMA/iNSC implantation showed striking therapeutic effects of inhibiting GFAP-positive cells and glial scar formation while simultaneously promoting axonal regeneration. Undoubtedly, use of this 3D hydrogel stem cell-loaded system is a promising therapeutic strategy for SCI repair.