Nanoscale Treatment of Intervertebral Disc Degeneration: Mesenchymal Stem Cell Exosome Transplantation.

A common surgical disease, intervertebral disc degeneration (IVDD), is increasing at an alarming rate in younger individuals. Repairing damaged intervertebral discs (IVDs) and promoting IVD tissue regeneration at the molecular level are important research goals.Exosomes are extracellular vesicles (EVs) secreted by cells and can be derived from most body fluids. Mesenchymal stem cell-derived exosomes (MSC-exos) have characteristics similar to those of the parental MSCs. These EVs can shuttle various macromolecular substances, such as proteins, messenger RNAs (mRNAs), and microRNAs (miRNAs) and regulate the activity of recipient cells through intercellular communication. Reducing inflammation and apoptosis can significantly promote IVD regeneration to facilitate the repair of the IVD. Compared with MSCs, exosomes are more convenient to store and transport, and the use of exosomes can prevent the risk of rejection with cell transplantation. Furthermore, MSC-exo-mediated treatment may be safer and more effective than MSC transplantation. In this review, we summarize the use of bone marrow mesenchymal stem cells (BMSCs), adipose-derived mesenchymal stem cells (AMSCs), nucleus pulposus mesenchymal stem cells (NPMSCs), and stem cells from other sources for tissue engineering and use in IVDD. Here, we aim to describe the role of exosomes in inhibiting IVDD, their potential therapeutic effects, the results of the most recent research, and their clinical application prospects to provide an overview for researchers seeking to explore new treatment strategies and improve the efficacy of IVDD treatment.

Bioprinting for bone tissue engineering.

The shape transformation characteristics of four-dimensional (4D)-printed bone structures can meet the individual bone regeneration needs, while their structure can be programmed to cross-link or reassemble by stimulating responsive materials. At the same time, it can be used to design vascularized bone structures that help establish a bionic microenvironment, thus influencing cellular behavior and enhancing stem cell differentiation in the postprinting phase. These developments significantly improve conventional three-dimensional (3D)-printed bone structures with enhanced functional adaptability, providing theoretical support to fabricate bone structures to adapt to defective areas dynamically. The printing inks used are stimulus-responsive materials that enable spatiotemporal distribution, maintenance of bioactivity and cellular release for bone, vascular and neural tissue regeneration. This paper discusses the limitations of current bone defect therapies, 4D printing materials used to stimulate bone tissue engineering (e.g., hydrogels), the printing process, the printing classification and their value for clinical applications. We focus on summarizing the technical challenges faced to provide novel therapeutic implications for bone defect repair.

Biological Functions of the DNA Glycosylase NEIL3 and Its Role in Disease Progression Including Cancer.

The accumulation of oxidative DNA base damage can severely disrupt the integrity of the genome and is strongly associated with the development of cancer. DNA glycosylase is the critical enzyme that initiates the base excision repair (BER) pathway, recognizing and excising damaged bases. The Nei endonuclease VIII-like 3 (NEIL3) is an emerging DNA glycosylase essential in maintaining genome stability. With an in-depth study of the structure and function of NEIL3, we found that it has properties related to the process of base damage repair. For example, it not only prefers the base damage of single-stranded DNA (ssDNA), G-quadruplex and DNA interstrand crosslinks (ICLs), but also participates in the maintenance of replication fork stability and telomere integrity. In addition, NEIL3 is strongly associated with the progression of cancers and cardiovascular and neurological diseases, is incredibly significantly overexpressed in cancers, and may become an independent prognostic marker for cancer patients. Interestingly, circNEIL3, a circular RNA of exon-encoded origin by NEIL3, also promotes the development of multiple cancers. In this review, we have summarized the structure and the characteristics of NEIL3 to repair base damage. We have focused on NEIL3 and circNEIL3 in cancer development, progression and prognosis.

Osteopontin and its downstream carcinogenic molecules: regulatory mechanisms and prognostic value in cancer progression.

Osteopontin (OPN) is a multifunctional phosphorylated glycoprotein that is expressed at significantly elevated levels in various cancers. OPN overexpression is closely associated with the development of cancer progression such as proliferation, metastasis, angiogenesis, apoptosis resistance, drug resistance, and immunosuppression, and may also be an independent prognostic biomarker for a variety of cancers. This review broadly summarizes the mechanisms that regulate the expression of downstream oncogenic molecules after OPN binds to integrin receptors or CD44 receptors, which involve a complex intracellular "signaling traffic network" (including key kinases, signaling pathways, and transcription factors). In addition, we review the prognostic value of OPN, OPN synergistic downstream oncogenic molecules in the female breast, non-small cell lung, prostate, colorectal, gastric, and hepatocellular carcinomas. The prognostic value of OPN in tissues or blood may vary due to differences in study subjects or detection methods, and this aspect of the study requires further systematization with a view to applying the detection of OPN to clinical applications. Importantly, based on the fact that the oncogenic effect of OPN correlates with the expression of the above-mentioned oncogenic molecules, this work may provide some help in the study of combination therapy targeting OPN and the above-mentioned oncogenic molecules.

Aggressive strategies for regenerating intervertebral discs: stimulus-responsive composite hydrogels from single to multiscale delivery systems.

As our research on the physiopathology of intervertebral disc degeneration (IVD degeneration, IVDD) has advanced and tissue engineering has rapidly evolved, cell-, biomolecule- and nucleic acid-based hydrogel grafting strategies have been widely investigated for their ability to overcome the harsh microenvironment of IVDD. However, such single delivery systems suffer from excessive external dimensions, difficult performance control, the need for surgical implantation, and difficulty in eliminating degradation products. Stimulus-responsive composite hydrogels have good biocompatibility and controllable mechanical properties and can undergo solution-gel phase transition under certain conditions. Their combination with ready-to-use particles to form a multiscale delivery system may be a breakthrough for regenerative IVD strategies. In this paper, we focus on summarizing the progress of research on the stimulus response mechanisms of regenerative IVD-related biomaterials and their design as macro-, micro- and nanoparticles. Finally, we discuss multi-scale delivery systems as bioinks for bio-3D printing technology for customizing personalized artificial IVDs, which promises to take IVD regenerative strategies to new heights.

Lactotransferrin promotes intervertebral disc degeneration by regulating Fas and inhibiting human nucleus pulposus cell apoptosis.

BACKGROUND: In recent years, intervertebral disc (IVD) degeneration (IDD) has increased in age. There is still a lack of effective treatment in clinics, which cannot improve the condition of IDD at the level of etiology. OBJECTIVE: To explore IDD pathogenesis at the cellular and gene levels and investigate lactotransferrin (LTF) expression in IDD patients and its possible mechanism. METHODS: We downloaded the IDD data set from the Gene Expression Omnibus (GEO) database, screened the differentially expressed genes (DEGs) and hub genes and performed Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis to construct a protein-protein interaction (PPI) network. Subsequently, we verified LTF's regulatory mechanism through cell experiments. IL-1ß was used to intervene in nucleus pulposus cells (NPCs) to construct the IDD cell model, and LTF and Fas expression was detected by qRT-PCR. LTF inhibitor, Fas inhibitor, LTF mimic, and Fas mimic were used to intervene in each group. Western blotting was used to detect Fas, Caspase-3, Bax, and Bcl-2 expression. RESULTS: A total of 131 DEGs and 10 hub genes were screened. LTF mRNA in the IDD model was significantly higher than that in the control group, while Fas' mRNA was significantly lower. When LTF was upregulated or downregulated in NPCs, apoptosis marker expression showed the opposite trend. The rescue test showed that LTF and Fas' overexpression greatly enhanced NPC apoptosis. CONCLUSION: LTF promotes IDD progression by regulating Fas in NPCs, and it may be an effective gene therapy target.

TRIP13 knockdown inhibits the proliferation, migration, invasion, and promotes apoptosis by suppressing PI3K/AKT signaling pathway in U2OS cells.

BACKGROUND: Although osteosarcoma (OS) is the most common malignant bone tumor, the biological mechanism underlying its incidence and improvement remains unclear. This study investigated early diagnosis and treatment objectives using bioinformatics strategies and performed experimental verification. METHODS AND RESULTS: The top 10 OS hub genes-CCNA2, CCNB1, AURKA, TRIP13, RFC4, DLGAP5, NDC80, CDC20, CDK1, and KIF20A-were screened using bioinformatics methods. TRIP13 was chosen for validation after reviewing literature. TRIP13 was shown to be substantially expressed in OS tissues and cells, according to Western blotting (WB) and quantitative real-time polymerase chain reaction data. Subsequently, TRIP13 knockdown enhanced apoptosis and decreased proliferation, migration, and invasion in U2OS cells, as validated by the cell counting kit-8 test, Hoechst 33,258 staining, wound healing assay, and WB. In addition, the levels of p-PI3K/PI3K and p-AKT/AKT in U2OS cells markedly decreased after TRIP13 knockdown. Culturing U2OS cells, in which TRIP13 expression was downregulated, in a medium supplemented with a PI3K/AKT inhibitor further reduced their proliferation, migration, and invasion and increased their apoptosis. CONCLUSIONS: TRIP13 knockdown reduced U2OS cell proliferation, migration, and invasion via a possible mechanism involving the PI3K/AKT signaling pathway.

New Hope for Intervertebral Disc Degeneration: Bone Marrow Mesenchymal Stem Cells and Exosomes Derived from Bone Marrow Mesenchymal Stem Cell Transplantation.

Bone Marrow Mesenchymal Stem Cells (BMSCs), multidirectional cells with self-renewal capacity, can differentiate into many cell types and play essential roles in tissue healing and regenerative medicine. Cell experiments and in vivo research in animal models have shown that BMSCs can repair degenerative discs by promoting cell proliferation and expressing Extracellular Matrix (ECM) components, such as type II collagen and protein-polysaccharides. Delaying or reversing the Intervertebral Disc Degeneration (IDD) process at an etiological level may be an effective strategy. However, despite increasingly in-depth research, some deficiencies in cell transplantation timing and strategy remain, preventing the clinical application of cell transplantation. Exosomes exhibit the characteristics of the mother cells from which they are secreted and can inhibit Nucleus Pulposus Cell (NPC) apoptosis and delay IDD through intercellular communication. Furthermore, the use of exosomes effectively avoids problems associated with cell transplantation, such as immune rejection. This manuscript introduces almost all of the BMSCs and exosomes derived from BMSCs (BMSCs-Exos) described in the IDD literature. Many challenges regarding the use of cell transplantation and therapeutic exosome intervention for IDD remain to be overcome.

Targeted therapy for intervertebral disc degeneration: inhibiting apoptosis is a promising treatment strategy.

Intervertebral disc (IVD) degeneration (IDD) is a multifactorial pathological process associated with low back pain (LBP). The pathogenesis is complicated, and the main pathological changes are IVD cell apoptosis and extracellular matrix (ECM) degradation. Apoptotic cell loss leads to ECM degradation, which plays an essential role in IDD pathogenesis. Apoptosis regulation may be a potential attractive therapeutic strategy for IDD. Previous studies have shown that IVD cell apoptosis is mainly induced by the death receptor pathway, mitochondrial pathway, and endoplasmic reticulum stress (ERS) pathway. This article mainly summarizes the factors that induce IDD and apoptosis, the relationship between the three apoptotic pathways and IDD, and potential therapeutic strategies. Preliminary animal and cell experiments show that targeting apoptotic pathway genes or drug inhibition can effectively inhibit IVD cell apoptosis and slow IDD progression. Targeted apoptotic pathway inhibition may be an effective strategy to alleviate IDD at the gene level. This manuscript provides new insights and ideas for IDD therapy.