African swine fever is a severe animal infectious disease caused by African swine fever virus (ASFV), and the morbidity and mortality associated with virulent ASFV isolates are as high as 100%. Previous studies showed that the ability of ASFV to antagonize IFN production is closely related to its pathogenicity. Here, we report that ASFV HLJ/18 infection induced low levels of type I IFN and inhibited cGMP-AMP–induced type I IFN production in porcine alveolar macrophages that were isolated from specific pathogen-free Landrace piglets. Subsequently, an unbiased screen was performed to screen the ASFV genes with inhibitory effects on the type I IFN production. ASFV pI215L, a viral E2 ubiquitin–conjugating enzyme, was identified as one of the strongest inhibitory effectors on the production of type I IFN. Knockdown of pI215L expression inhibited ASFV replication and enhanced IFN-β production. However, inhibition of type I IFN production by pI215L was independent of its E2 enzyme activity. Furthermore, we found that pI215L inhibited type I IFN production and K63-linked polyubiquitination of TANK-binding kinase 1 through pI215L-binding RING finger protein 138 (RNF138). ASFV pI215L enhanced the interaction between RNF138 and RNF128 and promoted RNF138 to degrade RNF128, which resulted in reduced K63-linked polyubiquitination of TANK-binding kinase 1 and type І IFN production. Taken together, our findings reveal a novel immune escape mechanism of ASFV, which provides a clue to the design and development of an immune-sensitive attenuated live vaccine.
Porcine reproductive and respiratory syndrome virus (PRRSV) 1 and 2 differ in their recognition of CD163. Substitution of porcine CD163 SRCR5 domain with a human CD163-like SRCR8 confers resistance to PRRSV 1 but not PRRSV 2. The deletion of CD163 SRCR5 has been shown to confer resistance to PRRSV 1 in vivo and both PRRSV 1 and 2 in vitro . However, the anti-PRRSV 2 activity of modifying the CD163 SRCR5 domain has not yet been reported. Here, we describe the highly efficient generation of two pig breeds (Liang Guang Small Spotted and Large White pigs) lacking a short region of CD163 SRCR5, including the ligand-binding pocket. We generated a large number of gene-edited Large White pigs of the F0 generation for use in viral challenge studies. The results of this study show that these pigs are completely resistant to infection by species 2 PRRSV, JXA1, and MY strains. There were no clinical symptoms, pathological abnormalities, viremia, or anti-PRRSV antibodies in the CD163 SRCR5-edited pigs compared to wild-type controls after viral challenge. Porcine alveolar macrophages (PAMs) isolated from CD163 SRCR5-edited Large White pigs also displayed resistance to PRRSV in vitro . In addition, CD163 SRCR5-edited PAMs still exhibited a cytokine response to PRRSV infection, and no significant difference was observed in cytokine expression compared to wild-type PAMs. Taken together, these data suggest that CD163 SRCR5-edited pigs are resistant to PRRSV 2, providing a basis for the establishment of PRRSV-resistant pig lines for commercial application and further investigation of the essential region of SRCR5 involved in virus infection.
BackgroundMore evidence suggests that dorsal spinal cord microglia is an important site contributing to CB2 receptor-mediated analgesia. The upregulation of P2Y12 and P2Y13 purinoceptors in spinal dorsal horn microglia is involved in the development of pain behavior caused by peripheral nerve injury. However, it is not known whether the expression of P2Y12 and P2Y13 receptors at spinal dorsal horn will be influenced after CB2 receptor activation in neuropathic pain rats.MethodsChronic constriction injury (CCI) and intrathecal ADPbetaS injection were performed in rats to induce neuropathic pain. The paw withdrawal latency (PWL) was used to evaluate thermal hyperalgesia in neuropathic rats. The expression of P2Y12 and P2Y13 receptors, p-p38MAPK, and NF-kappaBp65 was detected with RT-PCR and western blotting analysis.ResultsTreatment with AM1241 produces a pronounced inhibition of CCI-induced thermal hyperalgesia and significantly inhibited the increased expression of P2Y12 and P2Y13 receptors at the mRNA and protein levels, which open up the possibility that P2Y12 and P2Y13 receptor expression are downregulated by CB2 receptor agonist AM1241 in CCI rats. Western blot analysis demonstrated that AM1241 reduced the elevated expression of p-p38MAPK and NF-κBp65 in the dorsal spinal cord induced by CCI. After administration with either SB203580 (p38MAPK inhibitor) or PDTC (NF-kappaB inhibitor), the levels of P2Y13 receptor expression in the dorsal spinal cord were lower than those in the CCI group. However, in CCI rats, the increased expression of P2Y12 receptor was prevented by intrathecal administration of PDTC but not by SB203580. In addition, minocycline significantly decreased the increased expression of P2Y12 and P2Y13 receptors. The similar results can be observed in ADPbetaS-treated rats. Intrathecal injection of ADPbataS causes thermal hyperalgesia and increased expression of P2Y12 and P2Y13 receptors in the dorsal spinal cord of naive rats. Moreover, intrathecal injection of AM1241 alleviates pain response and reduces the elevated expression of P2Y12 and P2Y13 receptors, p-p38MAPK, and NF-κBp65 in the dorsal spinal cord of ADPbetaS-treated rats. Intrathecal injection of SB203580 significantly inhibited the ADPbetaS-induced P2Y13 receptor expression, without affecting P2Y12 receptor expression. However, treatment with either SB203580 or PDTC effectively inhibited P2Y13 receptor expression compared to ADPbetaS-treated rats.ConclusionsIn CCI- and ADPbetaS-treated rats, AM1241 pretreatment could efficiently activate CB2 receptor, while inhibiting p38MAPK and NF-kappaB activation in the dorsal spinal cord. CB2 receptor stimulation decreased P2Y13 receptor expression via p38MAPK/NF-kappaB signaling. On the other hand, CB2 receptor activation decreased P2Y12 receptor expression via p38MAPK-independent NF-kappaB signaling pathway.
Nanoparticles (NPs) are unavoidably covered by a layer of immunogenic proteins upon injection into blood, such as immunoglobins and complements, which buries the active-targeting ligands and triggers the rapid clearance of NPs by the mononuclear phagocytic system. Low antifouling polyethylene glycol is used to inhibit the formation of the immunogenic corona but it leads to poor cellular uptake and the immunogen-related accelerated blood clearance (ABC) phenomenon in multiple administrations. Here, we develop surface maleimide-modified NPs that covalently conjugate in vivo plasma albumin in its corona upon exposure to blood. The in situ recruited low-immunogenic albumin-enriching corona is capable of protecting maleimide-decorated NPs from phagocytosis in the bloodstream, preventing the ABC phenomenon in the second administration, facilitating NP accumulation in the tumor site/cells by the passive EPR effect and albumin receptor-mediated active targeting, and finally improving the antitumor activity. Such findings suggest that the facile strategy, based on the in situ anchored albumin-enriching corona, is efficient at enabling maleimide-decorated NPs to acquire stealth and tumor-targeting ability.
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