Myelin debris phagocytosis in demyelinating disease.

Demyelinating diseases are often caused by a variety of triggers, including immune responses, viral infections, malnutrition, hypoxia, or genetic factors, all of which result in the loss of myelin in the nervous system. The accumulation of myelin debris at the lesion site leads to neuroinflammation and inhibits remyelination; therefore, it is crucial to promptly remove the myelin debris. Initially, Fc and complement receptors on cellular surfaces were the primary clearance receptors responsible for removing myelin debris. However, subsequent studies have unveiled the involvement of additional receptors, including Mac-2, TAM receptors, and the low-density lipoprotein receptor-related protein 1, in facilitating the removal process. In addition to microglia and macrophages, which serve as the primary effector cells in the disease phase, a variety of other cell types such as astrocytes, Schwann cells, and vascular endothelial cells have been demonstrated to engage in the phagocytosis of myelin debris. Furthermore, we have concluded that oligodendrocyte precursor cells, as myelination precursor cells, also exhibit this phagocytic capability. Moreover, our research group has innovatively identified the low-density lipoprotein receptor as a potential phagocytic receptor for myelin debris. In this article, we discuss the functional processes of various phagocytes in demyelinating diseases. We also highlight the alterations in signaling pathways triggered by phagocytosis, and provide a comprehensive overview of the various phagocytic receptors involved. Such insights are invaluable for pinpointing potential therapeutic strategies for the treatment of demyelinating diseases by targeting phagocytosis.

Olig2-enriched exosomes: A novel therapeutic approach for cuprizone-induced demyelination.

The research aims to study the therapeutic impact of HEK293-XPack-Olig2 cell-derived exosomes on remyelination of the corpus callosum in a cuprizone-induced demyelinating disease model. A lentiviral vector expressing Olig2 was constructed using XPack technology. The highly abundant Olig2 exosomes (ExoOs) were isolated by centrifugation for subsequent experiments. Western blot, nanoparticle tracking analysis (NTA), and electron microscopy showed no significant difference in particle size and morphology between Exos and ExoOs, and a high level of Olig2 expression could be detected in ExoOs, indicating that exosome modification by XPack technology was successful. The Black Gold/Fluromyelin staining analysis showed that the ExoOs group significantly reduced the demyelination area in the corpus callosum compared to the PBS and Exos groups. Additionally, the PDGFRα/APC staining of the demyelinating region revealed an increase in APC+ oligodendrocytes and a decrease in PDGFRα+ oligodendrocyte progenitor cells (OPCs) in the ExoOs group. Furthermore, there was evident myelin regeneration in the demyelinated areas after ExoOs treatment, with better g-ratio and a higher number of intact myelin compared to the other treatment groups. The level of Sox10 expression in the brain tissue of the ExoOs group were higher compared to those of the PBS and Exos groups. The demyelination process can be significantly slowed down by the XPack-modified exosomes, the differentiation of OPCs promoted, and myelin regeneration accelerated under pathological conditions. This process is presumed to be achieved by changing the expression level of intracellular differentiation-related genes after exosomes transport Olig2 enriched into oligodendrocyte progenitors.

Quercetin regulates dendritic cell activation by targeting STAT4 in the treatment of experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is a class of autoimmune diseases mainly caused by the immune system attacking the myelin sheath of the axons in the nervous system. Although the pathogenesis of MS is complex, studies have shown that dendritic cells (DCs) play a vital role in the pathogenesis of MS. Quercetin (QU) has a unique advantage in clinical application, especially for treating autoimmune diseases. However, the mechanism of QU in the treatment of experimental autoimmune encephalomyelitis (EAE) remains unclear. In this study, we explore the potential role of QU in EAE. Finally, we find that QU has anti-inflammatory activities and neural protective effects in EAE. The experimental results suggest that the cellular basis for QU's function is to inhibit the activation of DCs while modulating the Th17 cell differentiation in the co-culture system. Further, QU may target STAT4 to inhibit its activation in DCs. This work will be of great significance for the future development and utilization of QU.

Clinical Diagnostic Value of circ-ARHGER28 for Breast Cancer and its Effect on MCF 7 Cell Proliferation and Apoptosis.

BACKGROUND/AIM: Clinical diagnostic value of circ-ARHGER28 in breast cancer (BC), and the biological functions of circ-ARHGER28 on the proliferation and apoptosis of MCF-7 cells were investigated. MATERIALS AND METHODS: Human circRNA microarray was performed to analyze the expression of circRNAs in BC patients. RT-qPCR combined with bioinformatics analysis was applied to verify the candidate circRNAs in BC tissues and peripheral blood samples. Circ-ARHGER28 was chosen as the candidate gene for further research. The clinical diagnostic value and biological functions of circ-ARHGER28 were analyzed. The overexpression and negative control vector of circ-ARHGER28 were constructed and transfected to MCF-7 cells. The CCK 8 assay and clone formation experiments were applied to detect the cell proliferative and migratory abilities. Flow cytometry was used to analyze cell apoptosis and cell cycle distribution. RT-qPCR and Western blot were performed to detect apoptosis and expression of PI3K/AKT/mTOR-associated genes and proteins. RESULTS: Overexpression of circ-ARHGER28 inhibited the proliferation, colony formation and migration of MCF-7 cells, while increasing the population of the cells in the G2/M phase and the apoptotic rate. Apoptosis associated genes and proteins were significantly increased, whereas gene and protein expression of PI3K, AKT and mTOR were decreased in the cells. CONCLUSION: Circular RNA ARHGER28 exhibits promising diagnostic value for BC. Circ-ARHGER28 inhibited MCF-7 cell proliferation and increased the apoptotic rate. The function of circ-ARHGER28 was associated with the PI3K/AKT/mTOR signaling pathway. Circ-ARHGER28 could be an ideal biomarker for BC diagnosis and a novel target for BC therapy.

[Randomized,double-blind,parallel controlled,multicenter clinical trial of effectiveness and safety of Shexiang Zhuifeng Zhitong Ointment in alleviating pain in knee osteoarthritis(syndrome of cold-dampness obstruction)].

The Shexiang Zhuifeng Zhitong Ointment with the effects of dispelling wind, removing dampness, dissipating cold, and relieving pain is used for treating arthralgia, muscular pain, and sprain pain caused by cold-dampness obstruction. To evaluate the efficacy and safety of Shexiang Zhuifeng Zhitong Ointment in relieving the pain due to knee osteoarthritis(syndrome of cold-dampness obstruction), a randomized, double-blind, parallel controlled, multicenter clinical trial was conducted. The stratified randomization method was used to randomize the 240 subjects into a treatment group and a control group in a ratio of 1∶1. In each group, 60 patients received external application for 12 h and the other 60 patients received external application for 6 h. The treatment group received external application of Shexiang Zhuifeng Zhitong Ointment, while the control group received external application of Shexiang Zhuifeng Ointment. The treatment lasted for 21 days in both groups. Follow-up was conducted on days 7, 14, and 21 of treatment. The results based on the full analysis set were as follows.(1)In visual analog scale(VAS) score, the mean difference in the VAS score between baseline and 12 h post-treatment was 3.02 in the treatment group and 2.31 in the control group, with a significant difference(P<0.05). The mean difference in the VAS score between baseline and 6 h post-treatment was 3.19 in the treatment group and 2.48 in the control group, with a significant difference(P<0.05).(2)Response rate in terms of VAS score, after treatment for 12 h, the response rate was 93.22% in the treatment group and 73.33% in the control group, with a significant difference(P<0.05). After treatment for 6 h, theresponse rate in the treatment group was 88.33%, which was higher than that(63.33%) in the control group(P<0.05).The results showed that Shexiang Zhuifeng Zhitong Ointment applied for 12 and 6 h effectively relieved the knee joint pain of patients with knee osteoarthritis due to cold-dampness obstruction, as demonstrated by the reduced VAS score, Western Ontario and McMaster Universities Arthritis Index(WOMAC), stiffness, and joint function score. Moreover, Shexiang Zhuifeng Zhitong Ointment outperformed the positive control Shexiang Zhuifeng Ointment in terms of reducing the VAS score, demonstrating a definitetherapeutic effect on the pain due to knee osteoarthritis(syndrome of cold-dampness obstruction).In addition, Shexiang Zhuifeng Zhitong Ointment did not cause other adverse reactions except for mild allergic reactions, which were common in the external application of traditional Chinese medicine plasters on the skin, inseveral patients.Neither other adverse reactions nor abnormalities of liver and kidney functions and electrocardiogram were observed. This ointment had high safety and could be popularized in clinical application.

Engineered PDGFA-ligand-modified exosomes delivery T3 for demyelinating disease targeted therapy.

Demyelination is a proper syndrome in plenty of central nervous system (CNS) diseases, which is the main obstacle to recovery and still lacks an effective treatment. To overcome the limitations of the brain-blood barrier on drug permeability, we modified an exosome secreted by neural stem cells (NSCs), which had transfected with lentivirus armed with platelet-derived growth factors A (PDGFA)-ligand. Through the in vivo and in vitro exosomes targeting test, the migration ability to the lesion areas and OPCs significantly improved after ligand modification. Furthermore, the targeted exosomes loaded with 3,5, 30-L-triiodothyronine (T3) have a critical myelination ability in CNS development, administrated to the cuprizone animal model treatment. The data shows that the novel drug vector loaded with T3 significantly promotes remyelination compared with T3 alone. At the same time, it improved the CNS microenvironment by reducing astrogliosis, inhibiting pro-inflammatory microglia, and alleviating axon damage. This investigation provides a straightforward strategy to produce a targeting exosome and indicates a possible therapeutic manner for demyelinating disease.

Autophagy in Multiple Sclerosis: Phagocytosis and Autophagy of Oligodendrocyte Precursor Cells.

Multiple sclerosis (MS) is a leading cause of chronic neurological dysfunction in young to middle-aged adults, affecting approximately 2.5 million people worldwide. It is characterized by inflammation, multifocal demyelination, axonal loss, and white and gray matter gliosis. Autophagy is a highly conserved protein degradation pathway. Polymorphisms in autophagy-related genes have been implicated in a variety of autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, psoriasis and MS. However, the significance of autophagy in MS remains to be elucidated. This paper aims to explore the potential role of autophagy-related genes in MS diseases by using bioinformatics combined with machine learning methods. Finally, we obtained 9 autophagy genes with the highest correlation with MS, and further changes in these autophagy genes were verified in the experimental autoimmune encephalomyelitis (EAE) model and oligodendrocyte precursor cells (OPCs) engulfed myelin debris (MD). Combined with bioinformatic analysis and experimental data, Becn1 showed obvious expression abnormalities suggesting that this gene has vital functions in autophagy and MD engulfed by OPCs. This work will be of great significance for the further exploration of autophagy-related genes in demyelinating diseases.

Microglia-derived exosomes modulate myelin regeneration via miR-615-5p/MYRF axis.

Demyelination and failure of remyelination in the central nervous system (CNS) characterize a number of neurological disorders. Spontaneous remyelination in demyelinating diseases is limited, as oligodendrocyte precursor cells (OPCs), which are often present in demyelinated lesions in abundance, mostly fail to differentiate into oligodendrocytes, the myelinating cells in the CNS. In addition to OPCs, the lesions are assembled numbers of activated resident microglia/infiltrated macrophages; however, the mechanisms and potential role of interactions between the microglia/macrophages and OPCs are poorly understood. Here, we generated a transcriptional profile of exosomes from activated microglia, and found that miR-615-5p was elevated. miR-615-5p bound to 3'UTR of myelin regulator factor (MYRF), a crucial myelination transcription factor expressed in oligodendrocyte lineage cells. Mechanistically, exosomes from activated microglia transferred miR-615-5p to OPCs, which directly bound to MYRF and inhibited OPC maturation. Furthermore, an effect of AAV expressing miR-615-5p sponge in microglia was tested in experimental autoimmune encephalomyelitis (EAE) and cuprizone (CPZ)-induced demyelination model, the classical mouse models of multiple sclerosis. miR-615-5p sponge effectively alleviated disease progression and promoted remyelination. This study identifies miR-615-5p/MYRF as a new target for the therapy of demyelinating diseases.

Exosome-specific loading Sox10 for the treatment of Cuprizone-induced demyelinating model.

Demyelination is a pathological feature commonly observed in various central nervous system diseases. It is characterized by the aggregation of oligodendrocyte progenitor cells (OPCs) in the lesion area, which face difficulties in differentiating into mature oligodendrocytes (OLGs). The differentiation of OPCs requires the presence of Sox10, but its expression decreases under pathological conditions. Therefore, we propose a therapeutic strategy to regulate OPCs differentiation and achieve myelin repair by endogenously loading Sox10 into exosomes. To accomplish this, we generated a lentivirus-armed Sox10 that could anchor to the inner surface of the exosome membrane. We then infected HEK293 cells to obtain exosomes with high expression of Sox10 (exosomes-Sox10, ExoSs). In vitro, experiments confirmed that both Exos and ExoSs can be uptaken by OPCs, but only ExoSs exhibit a pro-differentiation effect on OPCs. In vivo, we administered PBS, Exos, and ExoSs to cuprizone-induced demyelinating mice. The results demonstrated that ExoSs can regulate the differentiation of PDGFRα+ OPCs into APC+ OLGs and reduce myelin damage in the corpus callosum region of the mouse brain compared to other groups. Further testing suggests that Sox10 may have a reparative effect on the myelin sheath by enhancing the expression of MBP, possibly facilitated by the exosome delivery of the protein into the lesion. This endogenously loaded technology holds promise as a strategy for protein-based drugs in the treatment of demyelinating diseases.