Chimeric CNS-targeting-peptide engineered exosomes for experimental autoimmune encephalomyelitis therapy.

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) that causes demyelination, neuronal damage and white matter loss, but there is still no known cure. Exosomes are 30-200 nm-sized double-layered membrane vesicles that can easily cross the blood-brain barrier (BBB). Exosomes from umbilical cord mesenchymal stem cells（UMSCs） have been found to treat experimental autoimmune encephalomyelitis (EAE) through the action of anti-inflammatory and immunomodulatory, but its clinical translation has been hampered by their inefficacious accumulation in CNS. Therefore, we developed a TAxI-exos, also known as a TAxI-peptide-chimeric UMSC-exos, for CNS-specific accumulation and curative effect in EAE. We used the EAE model in vivo as well as active T cell and BV-2 cell models in vitro to explore the efficacy and mechanisms. Exosomes from UMSCs with TAxI or DiR labels were given to EAE mice in one dosage (150 g) prior to the peak at day 15. The mice were sacrificed on day 30 so that spinal cords, spleens, and blood could be taken for analysis of demyelination, inflammation, microglia, T-cell subset proportions, and inflammatory cytokine expression. In vitro, PBMCs and splenocytes isolated from healthy C57BL/6 mice were activated and incubated with 0.15 mg/mL of UMSC-exos or TAxI-exos for immune mechanism investigations. Activated BV-2 cells were used to investigate the targeting and controlling polarization ability and mechanism of UMSC-exos and TAxI-exos. As expected, TAxI-exos exhibited significantly greater therapeutic action in EAE mice than UMSC-exos due to their improved targeting-ability. The medication reduced T-cell subset proportions and inflammation, reduced active-microglia proportions and promoted M1 to M2 microglial cell polarization through TNF pathway, upregulated IL-4, IL-10, TGF-ß, and IDO-1 expression, and downregulated IL-2, IL-6, IL-17A, IFN-γ, and TNF-α. The CNS-targeting properties of TAxI-exos and their capacity to inhibit degenerative processes in EAE mice have considerable potential therapeutic value for MS and other CNS illnesses.

The Protective Effect of Cx43 Protein-Mediated Phosphocreatine on Myocardial Ischemia/Reperfusion Injury.

OBJECTIVES: To verify the protective effect of phosphocreatine on myocardium in an ischemic model and the possible mechanism of action. METHODS: The model of myocardial ischemia/reperfusion (I/R) was established by the ligation balloon method. 30 SD rats were randomly divided into three groups, n = 10 in each group. Sham operation group: the coronary artery was not blocked and observed for 120 minutes. The ischemia/reperfusion (I/R) group was given ischemia for 30 minutes and ischemia reperfusion for 90 minutes. Phosphocreatine (PCr) group: after 30 minutes of ischemia, the rats were intraperitoneally injected with PCr (200 mg/kg) for 90 minutes. The animal groups of myocardial ischemia/reperfusion model in vitro were the same as those in vivo. The heart was removed by thoracotomy and washed immediately in H-K buffer solution. Then, the heart was installed on the Langendorff instrument. The concentration of PCr perfusion fluid in the PCr group was 10 mmol/L. The changes in coronary blood flow in isolated myocardium were recorded. The heart rate and electrocardiogram were recorded by RM6240BT. At the end of the experiment, myocardial pathological sections and Cx43 immunofluorescence staining were made, and the contents of malondialdehyde (MDA) in myocardial tissue were detected. RESULTS: Phosphocreatinine treatment improved the myocardial ischemia model, performance in electrocardiogram (ECG) changes (ST segment apparent), and histological changes (decrease in necrotic myocardial cells, inflammatory cell infiltration, and a reduction in myocardial edema). At the same time, MDA decreased, while coronary blood flow and Cx43 expression significantly improved. CONCLUSIONS: Phosphocreatine can improve the electrocardiogram and restore histologic changes in ischemic myocardium and coronary blood flow. The postulated mechanism is by inhibiting the generation of free oxygen radicals and restoring the expression of Cx43 protein.

Arsenic trioxide ameliorates experimental autoimmune encephalomyelitis in C57BL/6 mice by inducing CD4+ T cell apoptosis.

BACKGROUND: Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system characterized by severe white matter demyelination. Because of its complex pathogenesis, there is no definite cure for MS. Experimental autoimmune encephalomyelitis (EAE) is an ideal animal model for the study of MS. Arsenic trioxide (ATO) is an ancient Chinese medicine used for its therapeutic properties with several autoimmune diseases. It is also used to inhibit acute immune rejection due to its anti-inflammatory and immunosuppressive properties. However, it is unclear whether ATO has a therapeutic effect on EAE, and the underlying mechanisms have not yet been clearly elucidated. In this study, we attempted to assess whether ATO could be used to ameliorate EAE in mice. METHODS: ATO (0.5 mg/kg/day) was administered intraperitoneally to EAE mice 10 days post-immunization for 8 days. On day 22 post-immunization, the spinal cord, spleen, and blood were collected to analyze demyelination, inflammation, microglia activation, and the proportion of CD4+ T cells. In vitro, for mechanistic studies, CD4+ T cells were sorted from the spleen of naïve C57BL/6 mice and treated with ATO and then used for an apoptosis assay, JC-1 staining, imaging under a transmission electron microscope, and western blotting. RESULTS: ATO delayed the onset of EAE and alleviated the severity of EAE in mice. Treatment with ATO also attenuated demyelination, alleviated inflammation, reduced microglia activation, and decreased the expression levels of IL-2, IFN-γ, IL-1ß, IL-6, and TNF-α in EAE mice. Moreover, the number and proportion of CD4+ T cells in the spinal cord, spleen, and peripheral blood were reduced in ATO-treated EAE mice. Finally, ATO induced CD4+ T cell apoptosis via the mitochondrial pathway both in vitro and in vivo. Additionally, the administration of ATO had no adverse effect on the heart, liver, or kidney function, nor did it induce apoptosis in the spinal cord. CONCLUSIONS: Overall, our findings indicated that ATO plays a protective role in the initiation and progression of EAE and has the potential to be a novel drug in the treatment of MS.