MiR-216a-5p has opposite effects on tumorigenesis and progression in the context of different tumors, acting as either a tumor suppressor or an oncogene. However, the expression and function of miR-216a-5p in pancreatic cancer (PC) is not well characterized. In this study, we found miR-216a-5p was significantly downregulated in PC tissues and cell lines, which showed a negative correlation with peripancreatic lymph, perineural invasion and TNM stage of PCs patients. We made use of functional assays to reveal that miR-216a-5p inhibited growth and migration of PC cells in vitro and in vivo. Then, by employing the bioinformatics analysis and luciferase reporter assay, we demonstrated TPT1 was a potential target of miR-216a-5p, which contributes to tumor malignance by mediating mTORC1 pathway-associated autophagy. Furthermore, bioinformatics analysis and RNA pulldown confirmed that miR-216a-5p was mediated by LINC01133, which sponge miR-216a-5p, as a competing endogenous RNA (ceRNA). Collectively, our study revealed an important role of LINC01133/miR-216a-5p/TPT1 axis in the genesis and progression of PCs, which provides potential biomarkers for clinical diagnosis and therapy of PCs.

F4 (K88) and F18 fimbriaed enterotoxigenic Escherichia coli (ETEC) are the predominant causes of porcine postweaning diarrhea (PWD), and vaccines are considered the most effective preventive approach against PWD. Since heterologous DNA integrated into bacterial chromosomes could be effectively expressed with stable inheritance, we chose probiotic EcNc (E. coli Nissle 1917 prototype cured of cryptic plasmids) as a delivery vector to express the heterologous F4 or both F4 and F18 fimbriae and sequentially assessed their immune efficacy of anti-F4 and F18 fimbriae in both murine and piglet models. Employing the CRISPR-cas9 technology, yjcS, pcadA, lacZ, yieN/trkD, maeB, and nth/tppB sites in the chromosome of an EcNc strain were targeted as integration sites to integrate F4 or F18 fimbriae cluster genes under the Ptet promotor to construct two recombinant integration probiotic strains (RIPSs), i.e., nth integration strain (EcNcΔnth/tppB::PtetF4) and multiple integration strain (EcNc::PtetF18x4::PtetF4x2). Expression of F4, both F4 and F18 fimbriae on the surfaces of two RIPSs, was verified with combined methods of agglutination assay, Western blot, and immunofluorescence microscopy. The recombinant strains have improved adherence to porcine intestinal epithelial cell lines. Mice and piglets immunized with the nth integration strain and multiple integration strain through gavage developed anti-F4 and both anti-F4 and anti-F18 IgG immune responses. Moreover, the serum antibodies from the immunized mice and piglets significantly inhibited the adherence of F4+ or both F4+ and F18+ ETEC wild-type strains to porcine intestinal cell lines in vitro, indicating the potential of RIPSs as promising probiotic strains plus vaccine candidates against F4+/F18+ ETEC infection.

Our previous study showed that pentagalloylglucose (PGG), a naturally occurring hydrolyzable phenolic tannin, possesses significant anti-rabies virus (RABV) activity. In BHK-21 cells, RABV induced the overactivation of signal transducer and activator of transcription 3 (STAT3) by suppressing the expression of suppressor of cytokine signaling 3 (SOCS3). Inhibition of STAT3 by niclosamide, small interfering RNA, or exogenous expression of SOCS3 all significantly suppressed the replication of RABV. Additionally, RABV-induced upregulation of microRNA 455-5p (miR-455-5p) downregulated SOCS3 by directly binding to the 3′ untranslated region (UTR) of SOCS3. Importantly, PGG effectively reversed the expression of miR-455-5p and its following SOCS3/STAT3 signaling pathway. Finally, activated STAT3 elicited the expression of interleukin-6 (IL-6), thereby contributing to RABV-associated encephalomyelitis; however, PGG restored the level of IL-6 in vitro and in vivo in a SOCS3/STAT3-dependent manner. Altogether, these data identify a new miR-455-5p/SOCS3/STAT3 signaling pathway that contributes to viral replication and IL-6 production in RABV-infected cells, with PGG exerting its antiviral effect by inhibiting the production of miR-455-5p and the activation of STAT3. IMPORTANCE Rabies virus causes lethal encephalitis in mammals and poses a serious public health threat in many parts of the world. Numerous strategies have been explored to combat rabies; however, their efficacy has always been unsatisfactory. We previously reported a new drug, PGG, which possesses a potent inhibitory activity on RABV replication. Herein, we describe the underlying mechanisms by which PGG exerts its anti-RABV activity. Our results show that RABV induces overactivation of STAT3 in BHK-21 cells, which facilitates viral replication. Importantly, PGG effectively inhibits the activity of STAT3 by disrupting the expression of miR-455-5p and increases the level of SOCS3 by directly targeting the 3′ UTR of SOCS3. Furthermore, the downregulated STAT3 inhibits the production of IL-6, thereby contributing to a reduction in the inflammatory response in vivo. Our study indicates that PGG effectively inhibits the replication of RABV by the miR-455-5p/SOCS3/STAT3/IL-6-dependent pathway.

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