Tibetan pig is well known for its strong disease resistance. However, little is known about the molecular basis of its strong resistance to disease. Stimulator of interferon (IFN) genes (STING), also known as MPYS/MITA/ERIS/TMEM173, is an adaptor that functions downstream of RIG-I and MAVS and upstream of TBK1 and plays a critical role in type I IFN induction. Here we report the first cloning and characterization of STING gene from Tibetan pig. The entire open reading frame (ORF) of the Tibetan porcine STING is 1137 bp, with a higher degree of sequence similarity with Landrace pig (98%) and cattle (88%) than with chimpanzee (84%), human (83%) or mouse (77%). The predicted protein is composed of 378 amino acids and has 4 putative transmembrane domains. Real-time quantitative PCR analysis indicated that Tibetan pig STING mRNA was most abundant in the lung and heart. Overexpression of Tibetan porcine STING led to upregulation of IFN-β and IFN-stimulated gene 15 (ISG15) in porcine jejunal epithelial cell line IPEC-J2 cells. This is the first study investigating the biological role of STING in intestinal epithelial cells, which lays a foundation for the further study of STING in intestinal innate immunity.

Enterotoxigenic Escherichia coli (ETEC) infection destroys the intestinal barrier integrity, in turn, disrupting intestinal homoeostasis. Low-molecular-weight chitosan (LMWC) is a water-soluble chitosan derivative with versatile biological properties. Herein, we examined whether LMWC could relieve ETEC-induced intestinal barrier damage in weaned pigs. Twenty-four weaned pigs were allotted to three treatments: (1) non-infected control; (2) ETEC-infected control; and (3) ETEC infection + LMWC supplementation (100 mg/kg). On day 12, pigs in the infected groups were administered 100 mL of ETEC at 2.6 × 109 colony-forming units/mL to induce intestinal barrier injury. Three days later, serum samples were obtained from all pigs, which were then slaughtered to collect intestinal samples. We evidenced that LMWC not only increased (P < 0.05) the occludin protein abundance but also decreased (P < 0.05) the interleukin-6, tumour necrosis factor-α and mast cell tryptase contents, and the apoptotic epithelial cell percentages, in the small intestine of ETEC-infected pigs. Furthermore, LMWC down-regulated (P < 0.05) the small intestinal expression levels of critical inflammatory- and apoptotic-related genes, such as Toll-like receptor 4 (TLR4) and tumour necrosis factor receptor 1 (TNFR1), as well as the intra-nuclear nuclear factor-κB (NF-κB) p65 protein abundance, in the ETEC-infected pigs. Our study indicated a protective effect of LMWC on ETEC-triggered intestinal barrier disruption in weaned pigs, which involves the repression of intestinal inflammatory responses via blocking the TLR4/NF-κB signalling pathway and the depression of epithelial cell death via TNFR1-dependent apoptosis.

Polymeric micelles (PMs) have been applied widely to transport hydrophobic drugs to tumor sites for cancer treatment. However, the low load efficiency of the drug in the PMs significantly reduces the therapeutic efficiency. We report here that disulfide-linked camptothecin (CPT) as a kind of dimeric drug can be effectively embedded in the core of poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL) PMs for improving drug-loading efficiency, and PEG can be used as a hydrophilic shell. Moreover, the dimeric CPT-loaded PCL-PEG-PCL PMs exhibited excellent solubility in phosphate-buffered saline (PBS) media and significant cytotoxicity to cancer cells.

(1) Background: Vitamin D (VD) plays a vital role in anti-viral innate immunity. However, the role of VD in anti-rotavirus and its mechanism is still unclear. The present study was performed to investigate whether VD alleviates rotavirus (RV) infection through a microRNA-155-5p (miR-155-5p)-mediated regulation of TANK-binding kinase 1 (TBK1)/interferon regulatory factors 3 (IRF3) signaling pathway in vivo and in vitro. (2) Methods: The efficacy of VD treatment was evaluated in DLY pig and IPEC-J2. Dual-luciferase reporter activity assay was performed to verify the role of miR-155-5p in 1α,25-dihydroxy-VD3 (1,25D3) mediating the regulation of the TBK1/IRF3 signaling pathway. (3) Results: A 5000 IU·kg-1 dietary VD3 supplementation attenuated RV-induced the decrease of the villus height and crypt depth (p < 0.05), and up-regulated TBK1, IRF3, and IFN-β mRNA expressions in the jejunum (p < 0.05). Incubation with 1,25D3 significantly decreased the RV mRNA expression and the RV antigen concentration, and increased the TBK1 mRNA and protein levels, and the phosphoprotein IRF3 (p-IRF3) level (p < 0.05). The expression of miR-155-5p was up-regulated in response to an RV infection in vivo and in vitro (p < 0.05). 1,25D3 significantly repressed the up-regulation of miR-155-5p in vivo and in vitro (p < 0.05). Overexpression of miR-155-5p remarkably suppressed the mRNA and protein levels of TBK1 and p-IRF3 (p < 0.01), while the inhibition of miR-155-5p had an opposite effect. Luciferase activity assays confirmed that miR-155-5p regulated RV replication by directly targeting TBK1, and miR-155-5p suppressed the TBK1 protein level (p < 0.01). (4) Conclusions: These results indicate that miR-155-5p is involved in 1,25D3 mediating the regulation of the TBK1/IRF3 signaling pathway by directly targeting TBK1.

Porcine epidemic diarrhea virus (PEDV) infection causes watery diarrhea and vomiting in piglets. The pathogenesis of PEDV infection is related to intestinal inflammation. It is known that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) has potent anti-inflammatory activity, but it is unknown whether 1,25(OH)2D3 can inhibit the PEDV-induced inflammatory response and the underlying mechanism. We used transcriptome analysis, gene and protein expression, RNA interference and overexpression, and other techniques to study the anti-inflammatory effects of 1,25(OH)2D3 on PEDV infection in IPEC-J2 cells. The results showed that interleukin 19 (IL-19) and C-C motif chemokine ligand 20 (CCL20) gene expression were enhanced with the increase in PEDV infection time in IPEC-J2 cells. Interestingly, 1,25(OH)2D3 supplementation obviously inhibited IL-19 and CCL20 expression induced by PEDV. Meanwhile, we also found that 1,25(OH)2D3 reduced p-NF-κB, p-STAT1, and p-STAT3 protein levels induced by PEDV at 24 h post-infection. IκBα and SOCS3, NF-κB, and STAT inhibitor respectively, were increased by 1,25(OH)2D3 supplementation upon PEDV infection. In addition, 1,25(OH)2D3 supplementation inhibited ISG15 and MxA expression induced by PEDV. Although 1,25(OH)2D3 suppressed the JAK/STAT signal pathway and antiviral gene expression, it had no significant effects on PEDV replication and IFN-α-induced antiviral effects. In addition, when the vitamin D receptor (VDR) was silenced by siRNA, the anti-inflammatory effect of 1,25(OH)2D3 was inhibited. Meanwhile, the overexpression of VDR significantly downregulated IL-19 and CCL20 expression induced by PEDV infection. Together, our results provide powerful evidence that 1,25(OH)2D3 could alleviate PEDV-induced inflammation by regulating the NF-κB and JAK/STAT signaling pathways through VDR. These results suggest that vitamin D could contribute to inhibiting intestinal inflammation and alleviating intestinal damage in PEDV-infected piglets, which offers new approaches for the development of nutritional strategies to prevent PEDV infection in piglets.

Post-translational modifications (PTMs) are important molecular processes that regulate organismal responses to different stresses. Ubiquitination modification is not only involved in human health but also plays crucial roles in plant growth, development, and responses to environmental stresses. In this study, we investigated the ubiquitination proteome changes in the salt-tolerant sugar beet monomeric additional line M14 under salt stress treatments. Based on the expression of the key genes of the ubiquitination system and the ubiquitination-modified proteins before and after salt stress, 30 min of 200 mM NaCl treatment and 6 h of 400 mM NaCl treatment were selected as time points. Through label-free proteomics, 4711 and 3607 proteins were identified in plants treated with 200 mM NaCl and 400 mM NaCl, respectively. Among them, 611 and 380 proteins were ubiquitinated, with 1085 and 625 ubiquitination sites, in the two salt stress conditions, respectively. A quantitative analysis revealed that 70 ubiquitinated proteins increased and 47 ubiquitinated proteins decreased. At the total protein level, 42 were induced and 20 were repressed with 200 mM NaCl, while 28 were induced and 27 were repressed with 400 mM NaCl. Gene ontology, KEGG pathway, protein interaction, and PTM crosstalk analyses were performed using the differentially ubiquitinated proteins. The differentially ubiquitinated proteins were mainly involved in cellular transcription and translation processes, signal transduction, metabolic pathways, and the ubiquitin/26S proteasome pathway. The uncovered ubiquitinated proteins constitute an important resource of the plant stress ubiquitinome, and they provide a theoretical basis for the marker-based molecular breeding of crops for enhanced stress tolerance.