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P277 is a 24 amino-acids peptide, residues 437–460 of human heat shock protein 60 (HSP60). P277 or sequence repeated 6 × P277 was previously found showing potency preventive and therapeutic anti-diabetes functions in NOD mice, but aroused atherosclerosis due to the induction of anti-HSP65 autoantibodies as reported. To determine the intrinsic B epitope sequence, we screened P277 with pepscan method and then proved by detection of sera IgG from peptide fragments vaccinated mouse and rabbits. Results indicated HSP60 443–448 (ALLRCI) is potential intrinsic B epitope sequence of P277. We modified P277 by deleting the former three amino acids of ALLRCI (VP) or replacing these six with alanine (AP). The detection of serum lipid parameter in NOD mice and aorta endothelial damage levels in high-cholesterol diets fed rabbits demonstrated that VP induced higher anti-diabetes efficacy and caused less arteriosclerosis-liked diseases separately. With less TLR2/4 activation of dendritic cells and macrophages, VP treatment reduced Th1 related P277 specific pro-inflammatory cytokines production and increased regulatory immune responses both in vivo and in vitro. These results indicated that optimized VP peptide might serve as a promising candidate for mouse type 1 diabetes therapy.

Transmissible gastroenteritis virus (TGEV) causes severe diarrhea and high mortality in newborn piglets. It is well established that porcine intestinal epithelium is the target of the TGEV infection, however the mechanism that TGEV invades the host epithelium remains largely unknown. Aminopeptidase N (APN) is a known receptor of TGEV. This study discovered that the extracellular receptor binding domain 1 pertaining to epidermal growth receptor (EGFR) interact with TGEV spike protein. APN and EGFR synergistically promote TGEV invasion. TGEV promotes APN and EGFR clustering early in infection. Furthermore APN and EGFR synergistically stimulate PI3K/AKT as well as MEK/ERK1/2 endocytosis signaling pathways. TGEV entry is via clathrin and caveolin mediated endocytosis in IPEC-J2 cells. TGEV binds with EGFR, and subsequently promotes EGFR internalization by a clathrin-mediated endocytosis pathway. These results show that EGFR is a co-factor of TGEV, and that it plays a synergistic role with APN early in TGEV infection., Highlights • EGFR acts as a co-factor for TGEV entry. • EGFR plays a synergistic role with APN early in TGEV infection. • TGEV internalization through the clathrin-mediated endocytosis pathway.

Mycoplasma hyopneumoniae (Mhp) is the primary etiological agent responsible for swine enzootic pneumonia (EP), a disease that cause tremendous economic losses all over the swine industry. Dendritic cells (DCs), the most effective antigen-presenting cells, are widely distributed beneath respiratory epithelium. DCs uptake and present antigens to T cells, to initiate protective immune responses or generate immune-mediated pathology in different infections. In this study, we investigated the changes in the different DCs subpopulations, T cells and SIgA positive cells counts in porcine nasal cavity after long time Mhp infection. We further evaluated the role of porcine DCs in Mhp exposure. Our results showed that the number of SLA-II-DR+SWC3a+DCs, SLA-II-DR+CD11b+ DCs, T cells, SIgA positive cells in nasal cavity were decreased after Mhp 28 days infection in vivo experiment. The antigen presenting ability of DCs were inhibited by Mhp exposure. DCs couldn't activate T-cell proliferation by down-regulating the antigen presenting molecule CD1a expression and promoting high level of IL-10 production. Further more, the expression levels of IL-12 and IFN-γ in DCs were decreased, suggesting that DCs favour for Th2 immune response development after Mhp exposure in vitro. Taken together, Mhp infection impairs the immune function which allows the persistence of Mhp and cause predispose pigs to secondary infections. The decline of DCs presentation ability is the reason why dysfunction and persistence in Mhp infection. These findings are benefit for exploring the pathogenic mechanisms of Mhp in pigs.

Background: Protease nexin-1 (PN-1) contributes to enhanced metastasis of cancer cells. In this study, we showed PN-1 levels were remarkably upregulated in breast cancer cells and tissues, we aimed to uncover an unidentified mechanism underlying the up-regulation of PN-1 in breast cancers. Methods: The up-regulation of PN-1 in MCF-7 spheroid cells and breast cancer tissues was detected by RNA sequencing and qRT-PCR. The functions of PN-1 on breast cancer cells were investigated. The signaling pathway involved in epidermal growth factor (EGF) up-regulated PN-1 in breast cancer cells was identified by specific inhibitors or siRNAs of the candidate downstream genes. The feedback regulation of EGF/MAPK/EGR1 signaling by PN-1 was analyzed by Enzyme-linked immunosorbent assay (ELISA) and western blotting. Findings: The up-regulation of PN-1 in breast cancer mainly promoted cell migration, invasion and stemness. We uncovered that EGF induced the expression of PN-1 via its transcriptional factor, early growth response protein 1 (EGR1), through cascade activation of epidermal growth factor receptor (EGFR) to the activation of protein kinase Cδ (PKCδ), mitogenactivated protein kinase (MEK) and extracellular signal-related kinase (ERK). We further demonstrated EGF-induced PN-1 up-regulation could promote breast tumor cell metastasis in the mouse model for human breast cancer lung and liver metastasis. We also proved there was a positive feedback towards the activation of EGF signals by overexpression of PN-1. Interpretation: Our findings reveal a novel signaling axis that up-regulated PN-1 expression in breast cancer cells, which may provide new insights into identifying novel therapeutic targets for breast cancer. Funding Statement: This project is funded by National Natural Science Foundation of China (Grant No. 81570696, No. 81702941). Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: All the patients provided written consent, and the experiments were approved by the Ethics Committee of China Pharmaceutical University (Nanjing, China).