The microRNA-211-5p/P2RX7/ERK/GPX4 axis regulates epilepsy-associated neuronal ferroptosis and oxidative stress.

Ferroptosis is an iron-dependent cell death mechanism involving the accumulation of lipid peroxides. As a critical regulator, glutathione peroxidase 4 (GPX4) has been demonstrated to be downregulated in epilepsy. However, the mechanism of ferroptosis in epilepsy remains unclear. In this study, bioinformatics analysis, analysis of epilepsy patient blood samples and cell and mouse experiments revealed strong associations among epilepsy, ferroptosis, microRNA-211-5p and purinergic receptor P2X 7 (P2RX7). P2RX7 is a nonselective ligand-gated homotrimeric cation channel, and its activation mainly increases neuronal activity during epileptic seizures. In our study, the upregulation of P2RX7 in epilepsy was attributed to the downregulation of microRNA (miR)-211-5p. Furthermore, P2RX7 has been found to regulate GPX4/HO-1 by alleviating lipid peroxidation induced by suppression of the MAPK/ERK signaling pathway in murine models. The dynamic decrease in miR-211-5p expression induces hypersynchronization and both nonconvulsive and convulsive seizures, and forebrain miR-211-5p suppression exacerbates long-lasting pentylenetetrazole-induced seizures. Additionally, in this study, induction of miR-211-5p expression or genetic-silencing of P2RX7 significantly reduced the seizure score and duration in murine models through the abovementioned pathways. These results suggest that the miR-211-5p/P2RX7 axis is a novel target for suppressing both ferroptosis and epilepsy.

Exosomes Derived From T Regulatory Cells Suppress CD8+ Cytotoxic T Lymphocyte Proliferation and Prolong Liver Allograft Survival.

BACKGROUND CD8+ cytotoxic T lymphocytes (CTLs) have been proved to exert crucial roles in immunological rejection. Exosomes (EXOs) secreted by CD4+CD25+ regulatory T (Treg) cells is believed to be deeply involved in immune regulation. Nevertheless, whether immunomodulatory effect of CD4+CD25+ Treg cells on CD8+ CTL depends on EXOs remains unknown and needs to be explored. MATERIAL AND METHODS We purified CD4+CD25+ Treg cells followed by in vitro amplification. EXOs in culture supernatants of Treg cells was separated and identified. The effect of CD4+CD25+ Treg cells and CD4+CD25+ Treg cells-derived EXOs on CD8+ CTL viability, proliferation, cell cycle mRNA, intracellular cytokines, and protein expression were investigated. RESULTS We successfully obtained EXOs from CD4+CD25+ Treg cells. The inhibition effect of EXOs on CD8+ CTL was concentration-dependent. In addition, the inhibition effect of CD4+CD25+ Treg cells could be reversed by GW4869, an EXOs inhibitor. The inhibition effect was associated with the regulation of IFN-γ and perforin. Our in vivo experiments proved that natural CD4+CD25+ Treg cells-released EXOs can prolong liver allograft survival. CONCLUSIONS CD4+CD25+ Treg cells-derived EXOs could become an alternative tool for manipulating the immune system to discover novel underlying immunomodulatory mechanisms.

Decreased Netrin-1 and Correlated Th17/Tregs Balance Disorder in Aß1-42 Induced Alzheimer's Disease Model Rats.

There is increasing evidence indicating that inflammation represents a key pathological component of Alzheimer's disease (AD). A possible factor that may contribute to this process is netrin-1, a neuronal guidance molecule. This molecule has been shown to exert an unexpected immunomodulatory function. However, the potential changes and correlations of netrin-1 with T helper 17/regulatory T cells (Th17/Tregs) as related to inflammation in AD has yet to be examined. In this study, netrin-1 and Th17/Tregs balance were investigated, and the relationship among netrin-1, Th17/Tregs and cognitive function were analyzed in a rat model of AD. In this model, a bilateral intracerebroventricular administration of Amyloid ß1-42 (Aß1-42) was used to produce spatial learning and memory deficits, as well as increased neuronal apoptosis, which were detected 7 days after injection for AD7d group and 14 days for AD14d group. Netrin-1 concentrations were significantly down regulated in both serum and cerebrospinal fluid (CSF) of these AD rats, effects which were strongly correlated with cognitive deficits. Increased levels of interleukin (IL)-17 and deceased IL-10 were observed in both the circulation and CSF and were also correlated with the percent of time spent in the target quadrant of AD in these rats. These changes resulted in netrin-1 concentrations being negatively correlated with IL-17 but positively correlated with IL-10 concentrations in the serum and CSF. We also found that the Th17/Tregs balance was disrupted in these AD rats. Collectively, these findings reveal that the reduction in netrin-1 and the correlated disruption of Th17/Tregs balance in AD rats may diminish the immunosuppressive effect of netrin-1 on Th17/Tregs in AD pathogenesis.

Effects of focal mild hypothermia on thrombin-induced brain edema formation and the expression of protease activated receptor-1, matrix metalloproteinase-9 and aquaporin 4 in rats.

Hypothermia is an effective neuroprotective treatment for brain injury caused by intracerebral hemorrhage (ICH). It is reported to reduce brain edema and neuronal cell death. Thrombin, a coagulation protease released from blood clots, is critical in brain edema formation following ICH. Protease activated receptor­1 (PAR­1), matrix metalloproteinase­9 (MMP­9) and aquaporin 4 (AQP4) are edema­associated mediators that have been implicated in ICH pathology. In the present study, thrombin was used to induce brain edema in adult male Sprague­Dawley rats. Differences between a focal mild hypothermic group (33±0.5˚C) and a normothermic group (37˚C) were investigated. Following hypothermia, brain water content and blood­brain barrier (BBB) disruption was assessed at 6, 24 and 48 h and subsequently at 3, 5 and 7 days. At the same time, the mRNA and protein expression of PAR­1, MMP­9 and AQP4 were also determined. It was identified that brain water content and BBB disruption increased at 6 h and reached a maximal level at 24 h in the normothermic group. The mRNA and protein expression levels of PAR­1, MMP­9 and AQP4 started to increase at 24 h and reached a maximal level at 48 h. Focal mild hypothermia tended to significantly reduce brain water content, BBB disruption and PAR­1, MMP­9 and AQP expression at 24 and 48 h. The present data suggest that focal mild hypothermia is an effective treatment for edema formation through moderation of the mRNA and protein expression of PAR­1, MMP­9 and AQP4.