Long non-coding RNAs in neurodegenerative diseases – Molecular mechanisms, liquid biopsy biomarkers, and therapeutic targets: A review

Neurodegenerative diseases (NDDs), such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD), are age-related disorders characterized by progressive neuronal loss, cognitive decline, and limited options for disease-modifying treatments. Increasing evidence suggests that long non-coding RNAs (lncRNAs) play significant roles in neurodevelopment, neuronal homeostasis, and disease progression; however, their involvement in shared pathogenic pathways and clinical applications remains inadequately defined. This review consolidates recent experimental, transcriptomic, bioinformatic, and emerging clinical findings regarding the role of lncRNAs in NDDs. We examine how lncRNAs modulate common disease mechanisms, including protein misfolding and aggregation, neuroinflammation, mitochondrial dysfunction, ferroptosis, synaptic failure, and aging-related neurodegenerative processes. These regulatory functions occur through various mechanisms, including epigenetic modifications, transcriptional regulation, post-transcriptional processes, and RNA-protein interactions, as well as novel mechanisms such as liquid-liquid phase separation (LLPS), peptide coding, and exosome-mediated intercellular communication. Current evidence supports the potential of lncRNAs as minimally invasive liquid biopsy biomarkers, detectable in blood, cerebrospinal fluid (CSF), and extracellular vesicles. Additionally, lncRNAs may serve as therapeutic targets through antisense oligonucleotides (ASOs), gene editing, and engineered delivery platforms. Overall, lncRNAs have emerged as central molecular regulators and promising candidates for translation in NDDs. Nonetheless, challenges related to specificity, validation, delivery across the blood-brain barrier, and clinical standardization must be addressed before their routine application in precision neurology.