NEAT1 Enhances MPP+-Induced Pyroptosis In SH-SY5Y Cells Via Targeting Mir-5047/YAF2 Signaling

Parkinson’s disease (PD) is the second most frequent neurodegenerative disease. The aim of our study is to explore the role and regulatory mechanism of long non-coding RNA (lncRNA) NEAT1 in the MPP+-induced neuron pyroptosis. The levels of miR-5047 and YAF2 mRNA were determined through qRT-PCR. TUNEL staining was carried out to analyze neuronal apoptosis. Luciferase activity assay was accomplished to analyze the combination of miR-5047 and NEAT1 and YAF2 3’-UTR. Besides, the concentrations of IL-1β and IL-18 in supernatant were analyzed by ELISA assay. The levels of protein were examined through Western blot. NEAT1 and YAF2 expression were increased, while miR-5047 level was declined in the SH-SY5Y cells treated with MPP+. NEAT1 was a positively regulator for the SH-SY5Y cells pyroptosis induced by MPP+. In addition, YAF2 was a downstream target of miR-5047. NEAT1 promoted YAF2 expression via inhibiting miR-5047. Importantly, the promotion of NEAT1 to SH-SY5Y cells pyroptosis induced by MPP+ was recused by miR-5047 mimic transfection and YAF2 downregulation. In conclusion, NEAT1 was increased in the SH-SY5Y cells treated with MPP+, and it promoted the MPP+-induced pyroptosis through facilitating YAF2 expression by sponging miR-5047.

Neurotoxin-mediated ­­potent activation of the axon degeneration regulator SARM1

Axon loss underlies symptom onset and progression in many neurodegenerative disorders. Axon degeneration in injury and disease is promoted by activation of the nicotinamide adenine dinucleotide (NAD)-consuming enzyme SARM1. Here, we report a novel activator of SARM1, a metabolite of the pesticide and neurotoxin vacor. Removal of SARM1 completely rescues mouse neurons from vacor-induced neuron and axon death in vitro and in vivo. We present the crystal structure the Drosophila SARM1 regulatory domain complexed with this activator, the vacor metabolite VMN, which as the most potent activator yet know is likely to support drug development for human SARM1 and NMNAT2 disorders. This study indicates the mechanism of neurotoxicity and pesticide action by vacor, raises important questions about other pyridines in wider use today, provides important new tools for drug discovery, and demonstrates that removing SARM1 can robustly block programmed axon death induced by toxicity as well as genetic mutation.

CNTM-02. Regulation of glioma-network integration by tumor mediated secretion of TSP-1

Glioma exists in the complex neural circuitry of the brain, making the interface between neoplastic and healthy neurons and glia potentially damaging to long range neural networks and stimulatory to tumor growth. Thrombospondin-1 (TSP-1), an astrocyte derived neurogenic factor expressed by glia of the normal brain, has been found to be upregulated in intratumoral regions with high network functional connectivity (HFC). This modified cell signaling represents cancer cell hijacking of normal physiology with direct impact on tumor biology. There is emerging evidence that neuronal activity influences glioma proliferation and gliomas promote neuronal hyperexcitability. In humans, we have recently shown that bidirectional cellular interactions between gliomas and neurons alter cognitive circuit dynamics and ultimately patient survival. Previously, a subpopulation of human high-grade glioma cells which are enriched for tumor cells with synaptogenic potential were identified (HFC-IHDwtGBM). We plan to study the mechanisms of TSP1 signaling in three different established glioma models (1) HFC-IDHwtGBM hippocampal neuron co-culture, (2) HFC-IDHwtGBM + induced neuron organoids, (3) patient derived xenografts (PDX) for in vivo GCaMP calcium imaging. This project aims to test the hypothesis that increased TSP-1 secretion from HFC-IHDwtGBM cells plays a central role in the maintenance of an invasive and proliferative tumor phenotype when compared with LFC-IHDwtGBM PDX. We hope our study guides future work focused on preventing the infiltration of tumor cells into healthy brain tissues.

IL-6/STAT3 Induced Neuron Apoptosis in Hypoxia by Downregulating ATF6 Expression

Background: Neuron apoptosis, regulated by endoplasmic reticulum (ER) stress in the hippocampus, is an essential factor influencing the cognitive impairment induced by hypobaric hypoxia. Hypoxia mainly changes the activating transcription factor (ATF6) pathway of ER stress. However, the role of ATF6 in neuron survival, apoptosis, and upstream regulation is still controversial.Methods: We established a hypobaric hypoxia-induced C57BL/6 murine model and cell lines exposed to 1% hypoxia, including PC12 and HT22. First, we tested the expressions of interleukin 6 (IL-6), IL-1β, and IL-10 in C57BL/6 mice’s hippocampus under hypoxia using enzyme-linked immunosorbent assay (ELISA). We determined the signal transducer and activator of transcription 3 (STAT3) phosphorylation at tyrosine (Tyr)705 by western blot and the expression of ATF6, 78-kDa glucose-regulated protein (GRP78), and C/-EBP homologous protein (CHOP) related to ER stress by immunofluorescence (IF), western blot, and qRT-PCR; they were then verified on the cell model. Additionally, IL-6 (40 ng/mL) and STAT3 siRNA were used to treat the PC12 cells for 48 and 4 h to activate or silence STAT3, respectively. Subsequently, the cells of siRNA group were exposed to 1% hypoxia for 48 h. Furthermore, the ATF6 and CHOP expressions were detected with western blot and qRT-PCR. Finally, we examined the binding of STAT3 to the ATF6 promoter by chromatin immunoprecipitation (ChIP)-seq.Results: The results showed that IL-6 increased, IL-10 decreased in the hypoxia group, and IL-1β showed no difference between the hypoxia and the normoxia groups. Neuron apoptosis was significantly elevated by exposure to hypoxia for 48h in PC12 cells. The hypobaric hypoxia-induced ER stress proteins, ATF6, GRP78, and CHOP, and the p-STAT3 (Tyr705) expressions increased both in in vivo and in vitro. Besides, STAT3 silencing significantly promoted the ATF6 expression and inhibited CHOP, while STAT3 activation downregulated the expression of ATF6 and upregulated CHOP in PC12 cells. The ChIP-seq assay demonstrated that p-STAT3 (Tyr705) protein could bind to the ATF6 promoter region in HT22 cells.Conclusion: Phosphorylation of STAT3 at the Tyr705 site contributes to hypoxia-induced neuron apoptosis by downregulating ATF6, which might explain the inflammatory reaction and apoptosis of the hippocampal neurons induced by ER stress.

Amyloid Prefibrillar Oligomers: The Surprising Commonalities in Their Structure and Activity

It has been proposed that a “common core” of pathologic pathways exists for the large family of amyloid-associated neurodegenerations, including Alzheimer’s, Parkinson’s, type II diabetes and Creutzfeldt–Jacob’s Disease. Aggregates of the involved proteins, independently from their primary sequence, induced neuron membrane permeabilization able to trigger an abnormal Ca2+ influx leading to synaptotoxicity, resulting in reduced expression of synaptic proteins and impaired synaptic transmission. Emerging evidence is now focusing on low-molecular-weight prefibrillar oligomers (PFOs), which mimic bacterial pore-forming toxins that form well-ordered oligomeric membrane-spanning pores. At the same time, the neuron membrane composition and its chemical microenvironment seem to play a pivotal role. In fact, the brain of AD patients contains increased fractions of anionic lipids able to favor cationic influx. However, up to now the existence of a specific “common structure” of the toxic aggregate, and a “common mechanism” by which it induces neuronal damage, synaptotoxicity and impaired synaptic transmission, is still an open hypothesis. In this review, we gathered information concerning this hypothesis, focusing on the proteins linked to several amyloid diseases. We noted commonalities in their structure and membrane activity, and their ability to induce Ca2+ influx, neurotoxicity, synaptotoxicity and impaired synaptic transmission.

Dexmedetomidine Attenuates Hippocampal Damage and Improves Cognition by Up-Regulating Glyoxalase1 in APP/PS1 Mice

Background: Dexmedetomidine (DEX), an α2-adrenoceptor agonist, has been reported to possess neuroprotective effects against postoperative cognitive impairment. GLO-1 plays a key role in the pathogenesis of Alzheimer’s disease (AD). Here, the primary goal was to assess whether DEX affect GLO-1 and protect cognition impairment in APP/PS1 transgenic mice.Methods: After DEX was intraperitoneally injected in APP/PS1 mice, behavior was tested by Water Maze to illustrate whether DEX treatment has a significantly positive effect on ameliorating the cognition deficits in AD. We assessed the effect of DEX on the expression of GLO-1 and the production of other oxidative stress factors by ELISA and Western blot. To determine whether DEX play roles in the Aβ induced neuron apoptosis, flow cytometry was used.Results: DEX treatment significantly ameliorated cognition deficits in APP/PS1 mice. DEX increased GLO-1 expression and decreased MG activity in the hippocampus. In addition, DEX increased activity of SOD, GSH and reduced the activity of MDA. In vitro, DEX could protect the neuron apoptosis induced by Aβ. GLO-1 inhibitor could block the protective role of DEX.Conclusion: Taken together, our findings suggest that DEX prevents progression of AD-like pathology through upregulating GLO-1.

CEBPA-AS1 knockdown alleviates OGD/R-induced neuron cell damage by the miR-24-3p/BOK axis

Cerebral ischemia/reperfusion (I/R) can lead to serious brain function impairments. Long noncoding RNA (lncRNA) CCAAT enhancer binding protein α antisense RNA 1 (CEBPA-AS1) was shown to be upregulated in human ischemic stroke. This work investigated the function and mechanism of CEBPA-AS1 in I/R. An oxygen-glucose deprivation/reperfusion (OGD/R) model was used to induce I/R injury in SH-SY5Y cells in vitro. RT-qPCR examined the expression of CEBPA-AS1, microRNA-24-3p (miR-24-3p), and Bcl-2-related ovarian killer (Bok). The cell viability, apoptosis, oxidative stress in OGD/R-treated cells were detected using CCK-8, flow cytometry, western blot, ELISA assays. The relationship among genes was tested by RNA pulldown and luciferase reporter assays. We found that OGD/R upregulated CEBPA-AS1 expression in SH-SY5Y cells. Functionally, CEBPA-AS1 depletion ameliorated OGD/R-induced apoptosis and oxidative stress in SH-SY5Y cells by reducing ROS production and superoxide dismutase (SOD) and glutathione (GSH). Mechanistic investigations indicated that CEBPA-AS1 acts as a sponge for miR-24-3p, and miR-24-3p binds to the BOK. Moreover, miR-24-3p upregulation or BOK downregulation antagonized the protective role of CEBPA-AS1 depletion in SH-SY5Y cells exposed to OGD/R. Overall, downregulation of CEBPA-AS1 exerts protective functions against OGD/R-induced injury by targeting the miR-24-3p/BOK axis.

Changes in Representation of Thalamic Projection Neurons within Prefrontal-Thalamic-Hippocampal Circuitry in a Rat Model of Third Trimester Binge Drinking

Alcohol exposure (AE) during the third trimester of pregnancy—a period known as the brain growth spurt (BGS)—could result in a diagnosis of a fetal alcohol spectrum disorder (FASD), a hallmark of which is impaired executive functioning (EF). Coordinated activity between prefrontal cortex and hippocampus is necessary for EF and thalamic nucleus reuniens (Re), which is required for prefrontal-hippocampal coordination, is damaged following high-dose AE during the BGS. The current experiment utilized high-dose AE (5.25 g/kg/day) during the BGS (i.e., postnatal days 4–9) of Long-Evans rat pups. AE reduces the number of neurons in Re into adulthood and selectively alters the proportion of Re neurons that simultaneously innervate both medial prefrontal cortex (mPFC) and ventral hippocampus (vHPC). The AE-induced change unique to Re→(mPFC + vHPC) projection neurons (neuron populations that innervate either mPFC or vHPC individually were unchanged) is not mediated by reduction in neuron number. These data are the first to examine mPFC-Re-HPC circuit connectivity in a rodent model of FASD, and suggest that both short-term AE-induced neuron loss and long-term changes in thalamic connectivity may be two distinct (but synergistic) mechanisms by which developmental AE can alter mPFC-Re-vHPC circuitry and impair EF throughout the lifespan.