CNS & Neurological Disorders - Drug Targets (Formerly Current Drug Targets - CNS & Neurological Disorders) - Volume 24, Issue 5, 2025

Parkinson’s disease (PD) is a neurodegenerative disorder that results from the progressive loss of neurons in the brain followed by symptoms such as slowness and rigidity in movement, sleep disorders, dementia and many more. The different mechanisms due to which the neuronal degeneration occurs have been discussed, such as mutation in PD related genes, formation of Lewy bodies, oxidation of dopamine. This review discusses current surgical treatment and gene therapies with novel developments proposed for PD. Gene therapy based on novel approaches will possess more potential advantages over the conventional methods. Currently, gene therapy for such disorders is still under the process of clinical trials and approval. The pathogenesis comes from the breakdown of dopaminergic neurons within substantia nigra (SN) by the action of tyrosinase enzyme and subsequent accumulation of α-synuclein within the neurons. These dopaminergic neurons are the main source of dopamine, the decline of which is responsible for the symptoms. So, gene therapy can possibly provide more stable supplementation and regulate the expression of tyrosinase enzyme, providing better symptomatic relief and lesser side effects. Dopamine replacement therapy is a well-studied gene therapy method for PD. Another approach involves introducing functional genes for enzymes such as tyrosine hydroxylase, cyclohydrolases, and decarboxylases with the help of engineered vectors such as AAV and LV. Further, the potential application of nanoparticles in gene therapy as an efficient gene delivery and imaging system has been discussed. Among these, lipid-based nanoparticles such as PILs offer important benefits in terms of enhanced bioavailability, permeability to the cells, and solubility. So, this review paper summarizes some of the advanced gene therapy approaches for PD and the current status of clinical research in the development of gene therapy using nanoparticles.

Depression is a serious mental health disorder that impacts more than 350 million individuals globally. While the roles of serotonin and norepinephrine in depression have been extensively studied, the importance of dopaminergic pathways—essential for mood, cognition, motor control, and endocrine function—often gets overlooked. This review focuses on four major dopamine (DA) circuits: the mesolimbic (MLP), mesocortical (MCP), nigrostriatal (NSP), and thalamic-tuberoinfundibular pathways (TTFP), and their roles in depression. The MLP, which is key to reward processing, is linked to anhedonia, a primary depression symptom. The MCP, projecting to the prefrontal cortex, affects cognitive issues like impaired attention and decision-making. The NSP, mainly responsible for motor control, is related to psychomotor retardation in depression, while the TTFP manages neuroendocrine responses, which are often disrupted in stress-related depressive conditions. Current antidepressant treatments mainly target serotonin and norepinephrine systems but tend to be less effective for patients with DArgic dysfunction, leading to treatment resistance. This review underscores emerging evidence that suggests targeting DArgic pathways could improve treatment outcomes, especially for symptoms like anhedonia and cognitive deficits that conventional therapies often fail to address. Future research should aim to combine advancements in neuroimaging, optogenetics, and genetic studies to better map DArgic pathways and create personalized treatment plans. This review highlights the potential for new therapies that focus on DA systems, which could pave the way for more effective and tailored approaches to treating depression.

Neurodisease, caused by undesired substances, can lead to mental health conditions like depression, anxiety and neurocognitive problems like dementia. These substances can be referred to as contaminants that can cause damage, corruption, and infection or reduce brain functionality. Contaminants, whether conceptual or physical, have the ability to disrupt many processes. These observations motivate us to investigate contaminants and neurotoxicity collaboratively. This study investigates the link between pollutants and neuro-disease, examining transmission pathways and categorization. It also provides information on resources, causes, and challenges to minimize contamination risks. Contamination may cause various neuro-diseases, including Alzheimer's, Parkinson's, multi-system atrophy, Huntington's, autism spectrum disorder, psychiatric disorder, dementia, meningitis, encephalitis, schizophrenia, anxiety, and depression. The negative effects depend on the nature and extent of exposure. A comprehensive literature search was conducted using databases such as PubMed and Scopus, focusing on studies published till 2024. Studies were selected based on their examination of the relationship between environmental contaminants and brain health, emphasizing transmission pathways and the resulting neurological outcomes. Findings indicate that contaminants can penetrate the blood-brain barrier (BBB) via nasal, gut, and auditory routes, triggering harmful neurophysiological processes. This review highlights the urgent need for increased global awareness, policy interventions, and preventive measures to mitigate the long-term impacts of environmental contaminants on brain health, particularly in emerging nations.