Revisão sistemática e metanálise de microRNAs desregulados derivados de biópsia líquidas como biomarcadores para esclerose lateral amiotrófica (ELA)

Abstract

The discovery of disease-specific biomarkers, such as microRNAs (miRNAs), has the potential to transform the landscape of Amyotrophic Lateral Sclerosis (ALS) by facilitating timely diagnosis, monitoring treatment response, and accelerating drug discovery. This advancement will ultimately improve the quality of life and survival rate of ALS patients. Despite more than a decade of research, no miRNA biomarker candidate has been translated into clinical practice. We conducted a systematic review and meta-analysis to quantitatively synthesize data from original studies that analyzed miRNA expression from liquid biopsies via PCR and compared them to healthy controls. The protocol for this study adhered to PRISMA guidelines and is registered in PROSPERO (CRD42021230232). We conducted a comprehensive search across PubMed, Embase, Web of Science, and Virtual Health Library databases, covering studies from 2000 to 2022 without language restrictions. Our search retrieved 2412 studies, of which 1344 duplicates were eliminated. We applied our exclusion criteria (non-original studies, non-ALS studies, non-human studies, and studies not related to miRNA expression) to the remaining 1068 studies, resulting in the removal of an additional 971 studies. After full-text screening of the remaining 97 studies, based on our eligibility criteria (patient studies; biological fluids as source material; ALS versus healthy controls; PCR-based evaluation or validation of miRNA expression; and clear statistical analysis), we identified 31 as eligible for qualitative synthesis. Most studies focused on sporadic ALS (38.7%), used the El-Escorial, or its revised version, as diagnostic criteria (45.2%), included fewer than 30 patients (58.1%), and fewer than half reported on the age of disease onset (38.7%). Information on therapeutic treatment was largely absent, with only seven studies providing any such details (22.6%). The primary source of tissue sampling was serum (38.7%), followed by extracellular vesicles (EVs) derived from different fluids (19.4%), cerebrospinal fluid (CSF; 12.9%), leukocytes (9.7%), plasma (9.7%), and peripheral blood (3.2%). Only two studies analyzed multiple tissues, including serum and CSF (3.2%), and serum, CSF, and leukocytes (3.2%). We analyzed data on 807 miRNA species from 31 studies, stratifying them by tissue source and direction of dysregulation (i.e., up-, down-, or unregulated). We identified consistently dysregulated miRNAs in serum (hsa-miR-3665, -4530, -4745-5p, -206); blood (hsa-miR-338-3p, -183-5p); CSF (hsa-miR-34a-3p); plasma (hsa-miR206); and neural-enriched extracellular vesicles from plasma (hsa-miR-146a-5p, -151a-5p, - 10b-5p, -29b-3p, and -4454). The meta-analysis further supported the upregulation of hsa-miR206, hsa-miR-338-3p, hsa-miR-146a-5p, and hsa-miR-151a-5p, and the downregulation of hsamiR-183-5p, hsa-miR-10b-5p, hsa-miR-29b-3p, and hsa-miR-4454 as consistent indicators of ALS across independent studies. Analysis of enriched pathways associated with consistently dysregulated miRNAs showed correlations with various processes and diseases, such as fatty acid biosynthesis and metabolism, and p53 and PI3-Akt signaling pathways. A discussion of the methodological variabilities and inconsistencies in miRNA expression across different studies is also presented. In conclusion, our results provide valuable insights into the current understanding of miRNA dysregulation in ALS patients, contributing to ongoing efforts to discover disease-specific biomarkers.