Intussusception is one of the most common causes of bowel obstruction in children. I/R in intussusception can result in mucosal erosion and hemorrhagic ulceration, as well as necrosis of the bowel, lung injury, and multiple-organ dysfunction syndrome . Oxidative stress can play a crucial role in I/R in pediatric intussusception . Early detection of intestinal I/R in intussusception can improve prognosis and reduce complications in the intestines and extraintestinal organs. Although many efforts have been made to identify biomarkers of pediatric intussusception and associated I/R, no definite biomarkers are currently available in clinical practice.
Non-coding RNAs (ncRNAs) can be released to circulate in the peripheral blood. Circulating levels of tRFs could be useful as biomarkers of some diseases and surrogate measures of disease progression [13, 14], indicating their potential use in diagnosis and assessment of I/R in pediatric intussusception. In our previous studies, we found I/R in both our animal models and our pediatric intussusception patients. Therefore, we decided to test the expression of tRFs in serum from patients and further focus on biological analysis to verify whether circulating tRFs could serve as potential biomarkers in pediatric intussusception and associated I/R.
In the present study, we first performed high-throughput sequencing (HTS) to detect the expression profiles of tRFs in pediatric intussusception patients. To validate differential expression in the sequencing data, we selected three dysregulated tRFs for qRT-PCR review to verify the authenticity of the profiles. We detected the most significantly upregulated tRFs—tRF-Leu-TAA-006, tRF-Gln-TTG-033, and tRF-Lys-TTT-028—in serum samples from patients. Our qRT-PCR results demonstrated that all three tRFs were significantly upregulated in patients compared with controls. Via GO analysis, we learned that the targeted genes of these differentially expressed tRFs were involved in metabolism, protein modification, binding, transferase activity, protein binding, DNA binding, heterocyclic compound binding, and organic cyclic-compound binding. In mapping all targeted genes to the KEGG database, we noted that they participated in the following: “AMPK signaling pathway”, “FoxO signaling pathway”, “Cellular senescence”, “Relaxin signaling pathway”, “RAS pathway”, “Protein procession”, “Signaling pathways regulating pluripotency of stem cells” and “Taurine and hypotaurine metabolism”. This is consistent with findings in the literature that these signaling pathways play important roles in I/R [17–22]. However, the involvement of these dysregulated tRFs and their target genes in I/R in the pediatric intussusception process via these signaling pathways require further studies.
To apply the expression values of serum tRFs and tiRNAs for clinical diagnosis, we analyzed the ROC curves. We found that serum tRF-Leu-TAA-006, tRF-Gln-TTG-033, and tRF-Lys-TTT-028 were significantly upregulated in pediatric intussusception children compared with controls. The results showed that AUCs of tRF-Leu-TAA-006, tRF-Gln-TTG-033, and tRF-Lys-TTT-028 were 0.984, 0.970, and 0.837, respectively (Fig. 5). These findings suggested that serum levels of these three tRFs might be involved in the development of pediatric intussusception and could become new biomarkers for pediatric intussusception.
There are some limitations in the present study. First, the sample size was relatively small. Second, only three tRFs identified in microarray experiments were validated via qRT-PCR. Future studies should be conducted with larger sample sizes and in-depth verification of more candidate genes. Finally, the potential mechanisms of tRF-Leu-TAA-006, tRF-Gln-TTG-033, and tRF-Lys-TTT-028 in pediatric intussusception still require further studies.
In conclusion, the present study provided an overall analysis of tRFs and tiRNAs in pediatric intussusception and indicated that tRF-Leu-TAA-006, tRF-Gln-TTG-033, and tRF-Lys-TTT-028 could play important roles in pediatric intussusception. Results of further biological analysis suggested that these three tRFs could serve as novel serological biomarkers with significant accuracy in diagnosing pediatric intussusception. We believe that our research could offer clues for further research into the mechanism of tRFs in pediatric intussusception.