Potential liquid biopsy markers of exosomal microRNAs in renal interstitial fibrosis blood and urine.

Objective: To explore more and better liquid biopsy markers of exosomal microRNAs (exo-miRNAs) in renal interstitial fibrosis (RIF) and to preliminary investigate the biological functions and signaling pathways involved in these markers.

Materials and methods: High-throughput miRNA sequencing was performed on blood and urine exo-miRNAs from three RIF patients and three healthy volunteers, and differential expression analysis and bioinformatic processing were performed.

Results: There were 13 differentially expressed exo-miRNA (DEexo-miRNA) between RIF and healthy blood, and 20 DEexo-miRNAs in urine. These were various DEexo-miRNAs in different specimens, and the former included PC-3p-213532_58, hsa-miR-338-5p_R-1, PC-5p-34127_410, pal-miR-9993a-3p_L+2R-1, and hsa-miR-26a-1-3p with intermediate expression levels; the latter involved hsa-miR-126-3p, hsa-miR-217-5p, hsa-miR-199b-3p_R-1, mmu-miR-5106_R-4_1ss1AG, and PC-5p-39041_356, and others, while hsa-miR-378a-3p, hsa-miR-143-3p_R+1, hsa-miR-183-5p, hsa-miR-126-3p, hsa-miR-155-5p_R-1, mmu-miR-5106_R-4_1ss1AG, hsa-miR-126-5p, and hsa-miR-199b-3p_R-1 had high expression levels. Bioinformatics analysis of the up-regulated DEmiRNA with high expression in urine showed that there are 291 target corresponding mRNAs for six of eight DEexo-miRNAs, with mmu-miR-5106_R-4_1ss1AG and hsa-miR-199b-3p_R-1 having no target gene found in TargetScan and miRanda. GO annotation revealed that GO:0005515 (protein binding) had the lowest P value, involving the most genes. KEGG analysis revealed that the signaling included the mTOR signaling pathway, autophagy - animal, etc., and hsa05200 (pathways in cancer) had a lower P value, involving the most genes.

Conclusions: Urine is a better sample for RIF exo-miRNA detection than blood. Urinary exosomal hsa-miR-143-3p_R+1, hsa-miR-183-5p, hsa-miR-126-3p, mmu-miR-5106_R-4_1ss1AG, hsa-miR-126-5p, and hsa-miR-199b-3p_R-1 are novel liquid biopsy markers for RIF. These DEexo-miRNA may be associated with the occurrence and development of RIF and may participate in specific biological processes by regulating the expression of their target mRNA. Further research may require exploring the specific functions and mechanisms of these miRNAs in RIF, as well as whether they can serve as diagnostic or therapeutic targets for RIF.