Evaluation of Long Non-coding RNA Expression Profiles in Peripheral Blood Mononuclear Cells of Patients with Parkinson's Disease

Fluid-based biomarkers for neurodegenerative diseases

Neurodegenerative diseases, such as Alzheimer's Disease (AD), Multiple Sclerosis (MS), Parkinson's Disease (PD), and Amyotrophic Lateral Sclerosis (ALS) are increasingly prevalent as global populations age. Fluid biomarkers, derived from cerebrospinal fluid (CSF), blood, saliva, urine, and exosomes, offer a promising solution for early diagnosis, prognosis, and disease monitoring. These biomarkers can reflect critical pathological processes like amyloid-beta (Aβ) deposition, tau protein hyperphosphorylation, α-syn misfolding, TDP-43 mislocalization and aggregation, and neuronal damage, enabling detection long before clinical symptoms emerge. Recent advances in blood-based biomarkers, particularly plasma Aβ, phosphorylated tau, and TDP-43, have shown diagnostic accuracy equivalent to CSF biomarkers, offering more accessible testing options. This review discusses the current challenges in fluid biomarker research, including variability, standardization, and sensitivity issues, and explores how combining multiple biomarkers with clinical symptoms improves diagnostic reliability. Ethical considerations, future directions involving extracellular vehicles (EVs), and the integration of artificial intelligence (AI) are also highlighted. Continued research efforts will be key to overcoming these obstacles, enabling fluid biomarkers to become crucial tools in personalized medicine for neurodegenerative diseases.

Potential Diagnostic Biomarkers of tRNA-Derived Small RNAs in PBMCs for Nonproliferative Diabetic Retinopathy in Patients With Type 2 Diabetes Mellitus

Purpose

This study aimed to reveal the altered expressions of transfer RNA (tRNA)-derived small RNAs (tsRNAs) in peripheral blood mononuclear cells and identify potential diagnostic biomarkers for nonproliferative diabetic retinopathy (NPDR) from patients with type 2 diabetes mellitus.

Methods

Fifty-three patients diagnosed with type 2 diabetes mellitus were enrolled, including 25 patients with NPDR and 28 patients without diabetic retinopathy (DR) as the control group. A small RNA microarray was performed to screen the differentially expressed tsRNAs. Reverse transcriptase quantitative polymerase chain reaction was used to validate the significantly altered tsRNAs in a screening cohort and a verification cohort. The target genes, their enriched functions, and signaling pathways were predicted by bioinformatics analyses.

Results

In total, 668 upregulated and 485 downregulated tsRNAs were found in the NPDR group by microarray. Eight tsRNAs were validated preliminarily to be altered significantly by reverse transcriptase quantitative polymerase chain reaction, and their target genes were enriched in cellular macromolecule metabolic process and ubiquitin-mediated proteolysis. The verification experiments confirmed the increased levels of 5'tiRNA-35-PheGAA-8, tRF3-28-PheGAA-1, and tRF3b-PheGAA-6, and the decreased levels of mt-tRF3-19-ArgTCG, mt-tRF3-20-ArgTCG, and mt-tRF3-21-ArgTCG in patients with NPDR, which may serve as potential biomarkers with clinical significance.

Conclusions

The study recognized the tsRNA expression changes in peripheral blood mononuclear cells from patients with NPDR and discovered potential diagnostic biomarkers that hold clinical significance.

Translational Relevance

The significantly altered tsRNAs identified in the study may serve as potential diagnostic biomarkers for patients with NPDR as well as possible molecular targets of the occurrence and development of DR.

Role of Epigenetic Modulation in Neurodegenerative Diseases: Implications of Phytochemical Interventions

Epigenetics defines changes in cell function without involving alterations in DNA sequence. Neuroepigenetics bridges neuroscience and epigenetics by regulating gene expression in the nervous system and its impact on brain function. With the increase in research in recent years, it was observed that alterations in the gene expression did not always originate from changes in the genetic sequence, which has led to understanding the role of epigenetics in neurodegenerative diseases (NDDs) including Alzheimer's disease (AD) and Parkinson's disease (PD). Epigenetic alterations contribute to the aberrant expression of genes involved in neuroinflammation, protein aggregation, and neuronal death. Natural phytochemicals have shown promise as potential therapeutic agents against NDDs because of their antioxidant, anti-inflammatory, and neuroprotective effects in cellular and animal models. For instance, resveratrol (grapes), curcumin (turmeric), and epigallocatechin gallate (EGCG; green tea) exhibit neuroprotective effects through their influence on DNA methylation patterns, histone acetylation, and non-coding RNA expression profiles. Phytochemicals also aid in slowing disease progression, preserving neuronal function, and enhancing cognitive and motor abilities. The present review focuses on various epigenetic modifications involved in the pathology of NDDs, including AD and PD, gene expression regulation related to epigenetic alterations, and the role of specific polyphenols in influencing epigenetic modifications in AD and PD.

Neuronal dysfunction and gene modulation by non-coding RNA in Parkinson's disease and synucleinopathies

Over the last few decades, emerging evidence suggests that non-coding RNAs (ncRNAs) including long-non-coding RNA (lncRNA), microRNA (miRNA) and circular-RNA (circRNA) contribute to the molecular events underlying progressive neuronal degeneration, and a plethora of ncRNAs have been identified significantly misregulated in many neurodegenerative diseases, including Parkinson's disease and synucleinopathy. Although a direct link between neuropathology and causative candidates has not been clearly established in many cases, the contribution of ncRNAs to the molecular processes leading to cellular dysfunction observed in neurodegenerative diseases has been addressed, suggesting that they may play a role in the pathophysiology of these diseases. Aim of the present Review is to overview and discuss recent literature focused on the role of RNA-based mechanisms involved in different aspects of neuronal pathology in Parkinson's disease and synucleinopathy models.