| Dysfunction Pattern: | After merging the two networks with transcription factors, more detailed information was presented in terms of PAITA pathogenesis. The Let-7 family was frequently annotated in our predicted miRNA-tRF/tiRNA-mRNA-TF complex networks, including let-7e-5p, let-7i-5p, let-7 f-5p, let-7 g-5p, and let-7b-3p. Let-7 miRNA was found to be the first known human miRNA with high evolutionary conservation. The Let-7 family was able to negatively regulate RAS expression by binding to the 3ʹUTR [20]. RAS is predominantly involved in AP and pancreatic cancer. This partially explains why let-7 may be a vital player in AP initiation-PAITA. Let-7’s target mRNAs, including cav2, smarca5, Rock2, and target TF Arid4b, have been found to have various cellular functions in pancreatic cancer, but their roles in the field of AP are still unknown. miR-21-3p was found to not only modulate the inflammatory response to promote AP [21] but also positively correlate with the severity of AP in patients and aggravate pancreatitis in rats. miR-30a-5p, annotated in our networks, was previously reported to be essential for inflammatory response control in pancreatic acinar cells through the TGF-beta signaling pathway [22]. The abundant miRNAs and their target mRNAs or transcription factors predicted in our study warrant further investigation into AP pathogenesis.
tRFs and miRNAs have similar lengths and functional mechanisms. tRF3-Thr-AGT is an outstanding player in PAITA, indicated by the highest fold change and low P value. TLC-S inhibited its expression dramatically. We first found that it was derived from angiogenin-mediated tRNA cleavage by angiogenin-siRNA verification. To validate its involvement in PAITA, a tRF3-Thr-AGT mimic and inhibitor were applied. The tRF3-Thr-AGT mimic restored tRF3-Thr-AGT expression in the AR42J cell line after exposure to TLC-S. Accordingly, the tRF3-Thr-AGT mimic decreased TLC-S-induced trypsinogen activation. On the other hand, the tRF3-Thr-AGT inhibitor significantly decreased its expression compared with the control group. Green fluorescence was emitted again by inhibiting tRF3-Thr-AGT. Collectively, the expression level of tRF3-Thr-AGT was inversely correlated with trypsinogen activation. tRF3 is cleaved from the 3ʹ end of mature tRNAs by exonuclease, Dicer or ANG digestion in the TψC loop [23]. It has been linked with B cell lymphoma [24] and HIV viral infection [25]. However, its potential roles in inflammatory disease warrant deep investigation. |