Project description:The capsaicin receptor, TRPV1, mediates the detection of noxious chemical and thermal stimuli by nociceptors, primary sensory neurons of the pain pathway. Overactivation of TRPV1 leads to cellular damage or death through calcium entry and excitotoxicity. We have exploited this phenomenon to conduct a systematic analysis of excitotoxicity through a genome-wide CRISPRi screen, thereby revealing a comprehensive network of regulatory pathways. We show that decreased expression of mitochondrial electron transport chain (ETC) components protects against capsaicin-induced toxicity and other challenges by mitigating both calcium imbalance and the generation of mitochondrial reactive oxygen species via distinct pathways. Moreover, we confirm the regulatory roles of the ETC in sensory neurons through gain-of-function and loss-of-function experiments. Interestingly, TRPV1+ sensory neurons maintain lower expression of ETC components and can better tolerate excitotoxicity and oxidative stress compared to other sensory neuron subtypes, implicating ETC tuning as an intrinsic cellular strategy that protects nociceptors against excitotoxicity.
Project description:Excitotoxicity is a primary pathological process directing neuronal cell death in both acute neurological disorders and neurodegenerative diseases such as ischemic stroke and Alzheimer’s disease. We use mouse cultured cortical neuron treated with 100uM of Glutamate for a model of excitotoxicity and applied N-terminomics (TAILS) method to identify the neuronal proteins aberrantly modified in excitotoxicity
Project description:Glutamate excitotoxicity plays a critical role in neurodegeneration by triggering NMDA receptorhyperactivation, leading to elevated synaptic calcium levels and subsequent neuronal cell death. Tobetter understand how glutamateaffects neurons in neurological diseases, we conducted acomprehensive analysis of molecular changes at the transcriptome and kinome levels.Our research used primary cortical cultures from rat embryos to study glutamate excitotoxicity. Non-neuronal cells,like astrocytes, typically enhance neuron tolerance to glutamate excitotoxicity. We useda neuron-rich cultured system and observed that the effects of glutamate on neurons are concentration-dependent. Intermediate doses of glutamate had significant neurotoxic effects, while high and lowdoses resulted in less cell mortality, aligning with previous findings related to calcium influx.Glutamate is known to inhibit protein synthesis in neurons and leads to a rise in cytosolic calcium, a keystep in synapticplasticity and delayed neuronal cell death. Kinome profiling indicated activation of PKAand PKG phosphorylation, essential for synaptic plasticity-related gene expression.
Project description:Excitotoxicity caused by over-stimulation of the ionotropic glutamate receptors is a key neuronal cell death process underpinning brain damage in acute and chronic neurological disorders such as ischaemic stroke, traumatic brain injury, and neurodegenerative diseases. Exactly how neurons die in excitotoxicity still remains unclear and is an important area of research in the field of neuroscience. In this current project we wanted to explore the global changes in proteome and phosphoproteome following glutamate excitotoxicity in cultured primary cortical neurons.
Project description:In recent decades, transcriptome analysis has been widely used to understand human disease pathogenesis and identify therapeutic targets and biomarkers. Accumulated reports in patients with neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease, have also provided evidence of dysregulated gene expression related to neuropathogenesis. However, obtaining samples from neurodegenerative patients is more challenging than other human diseases due to low accessibility. Also, brain tissues and cerebrospinal fluid are composed of multiple cell types, so they are unsuitable for obtaining neural cell-type-specific gene expression profiles. Thus, we here report gene expression profiles in primary neuronal cultures exposed to Aβ toxicity and glutamate excitotoxicity to understand pathological gene expression in neurons. By RNA-sequencing analysis, we compare transcriptomes and find that two groups of genes show similar expression patterns in Aβ toxicity excitotoxicity—they are either up- or down-regulated in both conditions. Genes in the two groups are related to synaptic function and cell signaling, which are well-known biological functions altered in Aβ toxicity and excitotoxicity. Interestingly, the analysis reveals a possibility that circadian clock (molecular oscillator generating daily rhythms)-related genes are dysregulated in both conditions. We confirm the reduced circadian transcription factor Bmal1 levels in Aβ toxicity and glutamate excitotoxicity. RNA-sequencing analysis in Bmal1-deleted neurons shows potential relationships between BMAL1 and synaptic functions. Thus, this transcriptome study provides evidence of the potential roles of the circadian clock in neuropathogenesis.