Biology subjects

Liu, X.-T.

Publications and source records attributed to Liu, X.-T..

5 recordsLinked to original sources

bioRxiv2023

ZBP1-mediated macrophage necroptosis inhibits ASFV replication

African swine fever (ASF) is an infectious disease characterized by hemorrhagic fever, highly pathogenic, and severe mortality in domestic pigs caused by the African swine fever virus (ASFV). ASFV is a large DNA virus and primarily infects porcine monocyte macrophages. The interaction between ASFV and host macrophages is the major reason for gross pathological lesions caused by ASFV. Necroptosis is an inflammatory programmed cell death and plays an important immune role during virus infection. However, whether and how ASFV induces macrophage necroptosis and what effect of necroptosis signaling on host immunity and ASFV infection remains unknown. This study uncovered that ASFV activates the necroptosis signaling in the spleen, lung, liver, and kidney from ASFV-infected pigs. And macrophage necroptosis also was induced by ASFV infection in vitro. Further evidence showed that the macrophage necroptosis is independent of TNF--RIPK1 or TLR-TRIF pathway but depends on Z-DNA binding protein 1 (ZBP1). ASFV infection upregulates the expression of ZBP1 and RIPK3 to consist of the ZBP1-RIPK3-MLKL necrosome and further activates macrophage necroptosis. Subsequently, multiple Z-DNA sequences were predicted to be present in the ASFV genome. And the Z-DNA signals were further confirmed to be present and colocalized with ZBP1 in the cytoplasm and nucleus of ASFV-infected cells. Moreover, ZBP1-mediated macrophage necroptosis caused the extracellular release of proinflammatory cytokines TNF- and IL-1{beta} induced by ASFV infection. Finally, we demonstrated that ZBP1-mediated necroptosis signaling significantly inhibits ASFV replication in host macrophages. Our findings uncovered a novel mechanism by which ASFV induces macrophage necroptosis by facilitating Z-DNA accumulation and ZBP1 necrosome assembly, providing significant insights into the pathogenesis of ASFV infection. ImportanceASFV infection causes an acute, febrile, hemorrhagic, and severely lethal disease in swine, which seriously threatens the global porcine industry. Understanding the interaction mechanism between ASFV and host macrophages during infection is essential for elucidating the pathogenesis of ASFV. To our knowledge, this study revealed the interaction mechanism between ASFV infection and host macrophage necroptosis. The results showed that ASFV infection induces macrophage necroptosis through ZBP1 activation instead of the TNF--RIPK1 or TLR-TRIF pathway. ASFV infection promotes Z-DNA accumulation, which causes ZBP1-RIPK3-MLKL necrosome assembly and macrophage necroptosis. The ZBP1-mediated necroptosis signaling facilitates the extracellular release of proinflammatory cytokines, inhibiting ASFV replication in host macrophages. This study found a new interaction mechanism between ASFV and host macrophages, which may help understand the pathogenesis caused by ASFV infection.

microbiology↗

bioRxiv2023

Comparative analysis of chemical cross-linking mass spectrometry data indicates that protein STY residues rarely react with N-hydroxysuccinimide ester cross-linkers

Chemical cross-linking of proteins coupled with mass spectrometry (CXMS) has enjoyed growing popularity in biomedical research. Most CXMS experiments utilize cross-linkers based on N-hydroxysuccinimide (NHS) ester, which react selectively with the amine groups found on the free N-termini of proteins and on the side chain of lysine (K) residues. It is also reported that under certain conditions they can react with the hydroxyl groups of serine (S), threonine (T), and tyrosine (Y). Some of the popular cross-link search engines including MeroX and xiSearch set STY, in addition to K, as cross-linkable sites by default. However, to what extent NHS ester cross-linkers react with STY under the typical CXMS experimental conditions remains unclear, nor has the reliability of STY-cross-link identifications. Here, by setting amino acids with chemically inert side chains such as glycine (G), valine (V), and leucine (L) as cross-linkable sites, which serves as a negative control, we show that software-identified STY-cross-links are only as reliable as GVL-cross-links. This is true across different NHS ester cross-linkers including DSS, DSSO, and DSBU, and across different search engines including MeroX, xiSearch, and pLink. Using a published dataset originated from synthetic peptides, we demonstrate that STY-cross-links indeed have a high false discovery rate. Further analysis revealed that depending on the data and the CXMS search engine used to analyze the data, up to 65% of the STY-cross-links identified are actually K-K cross-links of the same peptide pairs, up to 61% are actually K-mono-links, and the rest tend to contain short peptides at high risk of false identification.

biochemistry↗

bioRxiv2021

BNP facilitates NMB-mediated histaminergic itch via NPRC-NMBR crosstalk

B-type natriuretic peptide (BNP) binds to its two cognate receptors NPRA and NPRC, encoded by Npr1 and Npr3, respectively, with equal potency and both are expressed in the spinal cord. Moreover, natriuretic peptides (NP) signal through the inhibitory cGMP pathway, raising the question of how BNP may transmit itch information. We report that Npr3 is highly restricted to laminae I-II of the dorsal horn, and partially overlaps with neuromedin B receptor (NMBR) that encodes histaminergic itch. Functional studies indicate that NPRC is required for itch evoked by histamine but not chloroquine (CQ), a nonhistaminergic pruritogen. Importantly, BNP significantly facilitates scratching behaviors mediated by NMB, but not gastrin releasing peptide (GRP) that encodes nonhistaminergic itch. Consistently, BNP evoked Ca2+ response in NMBR/NPRC HEK 293 cells and BNP-saporin that ablated both Npr1 and Npr3 neurons impaired histamine-, but not CQ-evoked, itch. These results reveal a previously unknown mechanism by which BNP changes its inhibitory mode of action to the facilitation of itch through a novel NPRC-NMBR cross-talk. Our studies suggest that neuropeptides encode histaminergic and nonhistaminergic itch not only through distinct modes but also in synergy.

neuroscience↗

bioRxiv2020

Seneca Valley virus intercellular transmission mediated by exosomes

Exosomes are cup-shaped vesicles that are secreted by cells and are involved in the intercellular transport of a variety of substances, including proteins, RNA, and liposomes. Studies have shown that pathogenic microorganisms are contained in exosomes extracted from pathogenic micro-infected cells. The Seneca Valley virus (SVV) is a non-encapsulated single-stranded positive-strand RNA virus that causes ulceration in the pigs nose, the appearance of blisters, and other clinical symptoms similar to foot-and-mouth disease (FMD). Whether exosomes from SVV-infected cells can mediate SVV intercellular transmission is of great significance. There have been no studies showing whether exosomes can carry SVV in susceptible and non-susceptible cells. Here, we first extracted and identified exosomes from SVV-infected IBRS-2 cells. It was confirmed that replication of SVV can be inhibited when IBRS-2 cells treated with exosomes inbihitor GW4869. Furthermore, laser confocal microscopy and qRT-PCR experiments were performed to investigate whether exosomes can carry SVV and enable the virus to proliferate in susceptible and non-susceptible cells. Finally, exosome-mediated intercellular transmission can not be completely blocked by SVV-specific neutralizing antibodies. Taken together, this study showed that exosomes extracted from the SVV-infected IBRS-2 cells can carry SVV and transmit productive SVV infection between SVV susceptible and non-susceptible cells, this transmit infection is resistant to SVV specific neutralization antibody. IMPORTANCEExosomes participate in intercellular communnication between cells. Exosomes derived from virus-infected cells can mediate virus transmission or/and regulate immune response. However, the function of exosomes that from SVV-infected host cells during SVV transmission is unclear. Here, we demonstrate SVV can utilize host exosomes to establish productive infection in intercellular transmission. Furthermore, exosome-mediated SVV transmission is resistant to SVVV-specific neutralizing antibodies. This discovery sheds light on neutralizing antibodies resistant to SVVV transmission by exosomes as a potential immune evasion mechanism.

immunology↗

bioRxiv2018

Exploration of Sensory and Spinal Neurons Expressing GRP in Itch and Pain

Gastrin-releasing peptide (GRP) is a putative itch-specific neurotransmitter, but definite evidence in the dorsal root ganglion (DRG) and spinal cord is lacking. We generated and validated a Grp-Cre knock-in (GrpCre-KI) mouse line whereby Grp neurons are genetically labeled. Cre-dependent marking analysis revealed exclusive innervation of the upper epidermis of the skin by GRP fibers. Importantly, optical stimulation of Grp fibers expressing channel rhodopsin (ChR2) in the skin evoked itch but not pain-related scratching behaviors, while conditional deletion of Grp in sensory neurons attenuated non-histaminergic itch. In contrast, intersectional genetic ablation of spinal Grp neurons did not affect itch nor pain transmission. Our study demonstrates a role of GRP in sensory neurons in itch and suggests that GRP sensory neurons are dedicated to itch transmission. GrpCre-KI mice provide a long-sought avenue for investigating peripheral coding mechanism of itch and further interrogation of itch-nerve fibers in the skin under chronic pruritus.\n\nHighlightsO_LIValidated expression of a Grp-Cre knock-in line in sensory neurons that innervate the skin\nC_LIO_LIOpto-activation of Grp sensory neurons evokes itch behavior\nC_LIO_LIConditional deletion of Grp in sensory neurons reduces non-histaminergic itch behavior\nC_LIO_LIIntersectional ablation of Grp spinal neurons does not affect itch or pain behaviors\nC_LI

neuroscience↗