Micro(nano)plastics in the brain: Epigenetic perturbations in progression to neurodegenerative diseases

As global plastic production escalates, micro(nano)plastics (MNPs) have become pressing ecological and biomedical concerns. These pollutants are increasingly implicated in the pathogenesis of neurodegenerative diseases. Due to their nanoscale size and surface reactivity, MNPs can cross the blood-brain barrier, accumulating in neural tissues. Once internalized, they disrupt neuronal homeostasis by inducing oxidative stress, mitochondrial dysfunction, and chronic neuroinflammation, key processes in neurodegenerative progression. Mitochondria, central to neuronal energy and redox regulation, are particularly vulnerable, leading to impaired ATP production, elevated ROS, and pro-apoptotic signaling. Recent studies reveal that MNPs also induce epigenetic changes, including aberrant DNA methylation, histone modifications, and dysregulation of non-coding RNAs. These alterations can result in synaptic instability, persistent transcriptional reprogramming, and heightened susceptibility to diseases like Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis. The mitochondrial epigenome is a vital target of MNP-induced disruption, offering potential biomarkers like methylated mtDNA and microRNAs for early diagnosis and prognosis. Understanding the molecular mechanisms behind these epigenetic alterations is essential for developing practical diagnostic tools and therapies. This review provides a comprehensive overview of MNP-induced neurodegeneration, focusing on mitochondrial and epigenetic disruptions. Moreover, it explores emerging biosensing technologies for detecting MNP-induced epigenetic alterations, highlighting the urgent need for further investigation to fully understand the neurotoxic potential of MNPs and develop preventive and therapeutic strategies for mitigating their effects on brain health.