C9orf72 dipeptides activate the NLRP3 inflammasome

Inflammasome-Mediated Neuroinflammation: A Key Driver in Alzheimer's Disease Pathogenesis

Alzheimer's disease (AD) is a progressive neurodegenerative disorder predominantly affecting the elderly, characterized by memory loss, cognitive decline, and functional impairment. While hallmark pathological features include extracellular amyloid beta (Aβ) plaques and intracellular neurofibrillary tangles composed of hyperphosphorylated tau protein, increasing evidence points to chronic neuroinflammation as a key driver of disease progression. Among inflammatory mechanisms, the activation of the NLRP3 (nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3) inflammasome in microglia plays a pivotal role by amplifying neuroinflammatory cascades, exacerbating synaptic dysfunction, and accelerating neuronal loss. This review examines the molecular underpinnings of AD with a focus on NLRP3 inflammasome-mediated neuroinflammation, detailing the crosstalk between Aβ, tau pathology, and innate immune responses. Finally, we highlight emerging therapeutic strategies targeting NLRP3 inflammasome activation as promising avenues for mitigating neuroinflammation and slowing AD progression.

Targeting Gene C9orf72 Pathogenesis for Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal adult neurodegenerative disorder. Since no cure has been found, finding effective therapeutic targets for ALS remains a major challenge. Gene C9orf72 mutations with the formation of hexanucleotide repeat (GGGGCC) expansion (HRE) have been considered the most common genetic pathogenesis of ALS. The literature review indicates that the C9orf72 HRE causes both the gain-of-function toxicity and loss of function of C9ORF72. The formation of RNA foci and dipeptide repeats (DPRs) resulting from HRE is responsible for toxic function gain. The RNA foci can interfere with RNA processing, while DPRs directly bind to and sequester associated proteins to disrupt processes of rRNA synthesis, mRNA translation, autophagy, and nucleocytoplasmic transport. The mutations of C9orf72 and HRE result in the loss of functional C9ORF72. Under physiological conditions, C9ORF72 binds to Smith-Magenis chromosome region 8 and WD repeat-containing protein and forms a protein complex. Loss of C9ORF72 leads to autophagic impairment, increased oxidative stress, nucleocytoplasmic transport impairment, and inflammatory response. The attempted treatments for ALS have been tried by targeting C9orf72 HRE; however, the outcomes are far from satisfactory yet. More studies should be performed on pharmacological and molecular modulators against C9orf72 HRE to evaluate their efficacy by targeting HRE.

Tracing ALS Degeneration: Insights from Spinal Cord and Cortex Transcriptomes

BACKGROUND/OBJECTIVES

Amyotrophic Lateral Sclerosis is a progressive neurodegenerative disorder characterized by the loss of upper and lower motor neurons. Key factors contributing to neuronal death include mitochondrial energy damage, oxidative stress, and excitotoxicity. The frontal cortex is crucial for action initiation, planning, and voluntary movements whereas the spinal cord facilitates communication with the brain, walking, and reflexes. By investigating transcriptome data from the frontal cortex and spinal cord, we aim to elucidate common pathological mechanisms and pathways involved in ALS for understanding the disease progression and identifying potential therapeutic targets.

METHODS

In this study, we quantified gene and transcript expression patterns, predicted variants, and assessed their functional effects using computational tools. It also includes predicting variant-associated regulatory effects, constructing functional interaction networks, and performing a gene enrichment analysis.

RESULTS

We found novel genes for the upregulation of immune response, and the downregulation of metabolic-related and defective degradation processes in both the spinal cord and frontal cortex. Additionally, we observed the dysregulation of histone regulation and blood pressure-related genes specifically in the frontal cortex.

CONCLUSIONS

These results highlight the distinct and shared molecular disruptions in ALS, emphasizing the critical roles of immune response and metabolic dysfunction in neuronal degeneration. Targeting these pathways may provide new therapeutic avenues to combat neurodegeneration and preserve neuronal health.