Viral infection can induce endoplasmic reticulum stress(ERS)and unfolded protein re-sponse(UPR)in host cells,resulting in perturbation of endoplasmic reticulum homeostasis.To e-lucidate the action mechanism of isochlorogenic acid A(IAA)in regulating peste des petits rumi-nant virus(PPRV)-induced ERS and UPR,MTT assay,indirect immunofluorescence assay and Western blot were used to evaluate the anti-PPRV activity of IAA,and the effects of IAA on PPRV-induced ERS and PERK signaling pathway were studied by Western blot and quantitative real-time PCR.The results showed that the PPRV replication and virus-induced cytopathic in LDG-2 cells were significantly inhibited,and the survival rate of virus-infected cells was significantly in-creased due to IAA treatment.Compared with the virus control group,the expression levels of GRP78 and p-eIF2α,the ratios of p-PERK/PERK and p-eIF2α/eIF2α in IAA treated PPRV-infec-ted cells were significantly decreased.The expression level of GADD153 significantly decreased at 24,36 h,and significantly increased at 48,60 h.Furthermore,treatment with ERS inhibitor 4-PBA could significantly suppress the expression levels of GRP78,PPRV-N protein and GADD153 in PPRV-infected cells,and the ratios of p-eIF2α/eIF2α and p-PERK/PERK in PPRV-infected cells were also significantly decreased caused by treatment with IAA or 4-PBA and IAA combination.These findings implicated that the PPRV-induced ERS could be alleviated by inhibiting activation of the PERK-eIF2α-GADD1 53 signaling pathway,which led to restriction of PPRV replication in host cells.

Viral infection can induce endoplasmic reticulum stress(ERS)and unfolded protein reac-tion(UPR)in host cells.This study aims to further explore the effects of ERS induced by pest des petits ruminants virus(PPRV)infection on UPR signaling pathway,virus replication and apopto-sis of host cells.MTT assay,indirect immunofluorescence assay(IFA)and Western blot were used to observe the proliferation of PPRV in goat kidney cells(LDG-2).Western blot and real-time flu-orescence quantitative PCR(qRT-PCR)were used to observe the effects of PPRV infection on the expression levels of GRP78,PERK and its downstream signal molecules,apoptosis-related proteins Bcl-2 and Bax.The result indicated that the cell survival rate was significantly declined with evident cytopathic effect at 36 h post-infection,and the expression level of PPRV-N protein tended to be elevated,and was significantly higher than that of cell control at 30 h post-infection.Meanwhile,the expression levels of GRP78,p-eIF2α and GADD153,the ratio of p-PERK/PERK and p-eIF2α/eIF2α were significantly increased.Moreover,the expression levels of PPRV-N protein,GRP78,p-eIF2α and GADD1 53,the ratio of p-eIF2α/eIF2α and p-PERK/PERK were significantly decreased in PPRV-infected cells due to 4-PBA treatment.The expression level of apoptosis-related Bcl-2 was down-regulated,Bax was up-regulated,and the ratio of Bcl-2/Bax was significantly decreased.Therefore,the activation of PERK/eIF2α/GADD153 signaling pathway could be induced by PPRV infection resulting in alleviating of virus-induced ERS,which is beneficial to viral replication.Bloc-king PPRV-induced ERS could inhibit the activation of PERK signaling pathway and virus replica-tion.PPRV infection and prolonged ERS can induce apoptosis of LDG-2 cells.

MTT assay,indirect immunofluorescence assay(IFA)and real-time fluorescence quanti-tative PCR(qRT-PCR)were used to observe the proliferation of PPRV in goat kidney cells(LDG-2).Western blot and qRT-PCR were used to evaluate the effects of PPRV infection on the expres-sion levels of TLR2,MyD88,NF-κB signaling pathway-related factors and their downstream in-flammatory factors.The results indicated that the significantly decreased cell survival rate and ob-vious cytopathic effect were observed at 36 h post PPRV infection,and the mRNA expression level of PPRV-N gene was significantly up-regulated.At the same time,the expression levels of TLR2,MyD88,p-p65 and p-IκBα,the ratio of p-p65/p65 and p-IκBα/IκBα and the mRNA expression levels of downstream inflammatory factors TNFα,IL-1β,IL-4 and IL-10 were significantly increased.Mo-reover,the expression levels of PPRV-N mRNA,TLR2,MyD88,p-p65 and p-IκBα,the ratio of p-p65/p65 and p-IκBα/IκBα and the mRNA expression levels of downstream inflammatory factors IL-1β and IL-4 in PPRV-infected cells were significantly decreased in the presence of the inhibitor C29 of TLR2.These findings implied that the TLR2/MyD88/NF-κBα signaling pathway can be activated by PPRV infection,which is beneficial to the replication and spread of the virus.Blocking down the activation of TLR2 can inhibit MyD88/NF-κB signaling pathway and viral replication in PPRV-infected cells.

Objective:To investigate the effects of ovarian cancer domain containing protease-1 (OTUD1) gene on the typeⅠ interferon signaling pathway, and its impact on the antiviral effects of IFN-α.Methods:Dual-luciferase reporter assay was performed to detect the effects of OTUD1 gene on the transcriptional activity of interferon-stimulated response element (ISRE) promoter. Quantitative real-time PCR (qPCR) was used to detect the effects of OTUD1 on IFN-α-induced expression of interferon-stimulated genes (ISGs). The effects of OTUD1 gene on the expression of key proteins in the IFN-α signal transduction pathway were analyzed by Western blot, and its effects on IFN-α-mediated inhibition of hepatitis B virus replication were detected by qPCR and ELISA.Results:In HEK293T and Huh7.0 cells, OTUD1 down-regulated the transcriptional activity of ISRE promoter in the interferon signaling pathway and the expression of antiviral genes such as ISG15 and ISG56. In HEK293T cells, OTUD1 reduced the expression of phospho-Jak1 (p-JAK1) at protein level, but the catalytic inactive mutant of OTUD1 (C320S) could not regulate the expression of ISGs or p-JAK1. In Huh7.0 cells, OTUD1 antagonized the inhibitory effect of IFN-α on hepatitis B virus replication.Conclusions:OTUD1 with the ubiquitination activity can inhibit the interferon JAK-STAT signaling pathway and the expression of ISGs by down-regulating the expression of p-JAK1 protein. OTUD1 antagonizes the effect of IFN-α on viral replication and that may be related to the interferon-induced JAK-STAT signaling pathway.

Background: Peste des petits ruminants (PPR) is a contagious and fatal disease of sheep and goats. PPR virus (PPRV) infection induces endoplasmic reticulum (ER) stress-mediated unfolded protein response (UPR). The activation of UPR signaling pathways and their impact on apoptosis and virus replication remains controversial. Objectives: To investigate the role of PPRV-induced ER stress and the IRE1-XBP1 and IRE1-JNK pathways and their impact on apoptosis and virus replication. Methods: The cell viability and virus replication were assessed by 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, immunofluorescence assay, and Western blot. The expression of ER stress biomarker GRP78, IRE1, and its downstream molecules, PPRV-N protein, and apoptosis-related proteins was detected by Western blot and quantitative reverse transcription-polymerase chain reaction, respectively. 4-Phenylbutyric acid (4-PBA) and STF-083010 were respectively used to inhibit ER stress and IRE1 signaling pathway. Results: The expression of GRP78, IRE1α, p-IRE1α, XBP1s, JNK, p-JNK, caspase-3, caspase-9, Bax and PPRV-N were significantly up-regulated in PPRV-infected cells, the expression of Bcl-2 was significantly down-regulated. Due to 4-PBA treatment, the expression of GRP78, p-IRE1α, XBP1s, p-JNK, caspase-3, caspase-9, Bax, and PPRV-N were significantly downregulated, the expression of Bcl-2 was significantly up-regulated. Moreover, in PPRV-infected cells, the expression of p-IRE1α, p-JNK, Bax, and PPRV-N was significantly decreased, and the expression of Bcl-2 was increased in the presence of STF-083010. Conclusions PPRV infection induces ER stress and IRE1 activation, resulting in apoptosis and enhancement of virus replication through IRE1-XBP1s and IRE1-JNK pathways.

Tuberculosis (TB) is one of the deadly diseases caused by Mycobacterium tuberculosis (Mtb), which presents a significant public health challenge. Treatment of TB relies on the combination of several anti-TB drugs to create shorter and safer regimens. Therefore, new anti-TB agents working by different mechanisms are urgently needed. FtsZ, a tubulin-like protein with GTPase activity, forms a dynamic Z-ring in cell division. Most of FtsZ inhibitors are designed to inhibit GTPase activity. In Mtb, the function of Z-ring is modulated by SepF, a FtsZ binding protein. The FtsZ/SepF interaction is essential for FtsZ bundling and localization at the site of division. Here, we established a yeast two-hybrid based screening system to identify inhibitors of FtsZ/SepF interaction in M. tuberculosis. Using this system, we found compound T0349 showing strong anti-Mtb activity but with low toxicity to other bacteria strains and mice. Moreover, we have demonstrated that T0349 binds specifically to SepF to block FtsZ/SepF interaction by GST pull-down, fluorescence polarization (FP), surface plasmon resonance (SPR) and CRISPRi knockdown assays. Furthermore, T0349 can inhibit bacterial cell division by inducing filamentation and abnormal septum. Our data demonstrated that FtsZ/SepF interaction is a promising anti-TB drug target for identifying agents with novel mechanisms.

[This corrects the article DOI: 10.1016/j.apsb.2023.01.022.].

OBJECTIVE: To explore the genetic basis for a Chinese patient featuring cleidocranial dysplasia(CCD). METHODS: Genomic DNA was extracted from peripheral blood samples of the patient and his parents. Whole exome sequencing (WES) was carried out for the patient, and suspected variant was verified by Sanger sequencing. RESULTS: WES has identified a missense c.460G>T (p.Val154Phe) (GRCh37/hg19) variant of the RUNX2 gene. The variant was located in the Runt domain, a highly conserved region (PM1); it was not present in either the Genome Aggregation Database or the 1000 Genomes Project (PM2), and was predicted to have a deleterious effect on the gene product by multiple in silico prediction tools (PP3); the clinical phenotype of the patient was highly consistent with that of cleidocranial dysplasia (PP4). Furthermore, the variant was unreported in medical literature and was absent in both parents (PS2). Based on the American College of Medical Genetics and Genomics guidelines, the c.460 G>T variant of RUNX2 gene was predicted to be pathogenic (PS2+PM1+PM2+PP3+PP4). CONCLUSION The c.460G>T (p.Val154Phe) variant of the RUNX2 gene probably underlay the clinical phenotype in the patient. Above finding has enabled accurate diagnosis and expanded the spectrum of RUNX2 variants.
China ; Cleidocranial Dysplasia/genetics* ; Core Binding Factor Alpha 1 Subunit/genetics* ; Humans ; Mutation ; Whole Exome Sequencing

In Gram-negative bacteria, lipopolysaccharide transport (Lpt) protein LptA and LptC form a complex to transport LPS from the inner membrane (IM) to the outer membrane (OM). Blocking the interaction between LptA and LptC will lead to the defect of OM and cell death. Therefore, Lpt protein interaction could be used as a target to screen new drugs for killing Gram-negative bacteria. Here we used biolayer interferometry (BLI) assay to detect the interaction between LptA and LptC, with the aim to develop a method for screening the LptA/LptC interaction blockers in vitro. Firstly, LptC and LptA with or without signal peptide (LptAfull or LptAno signal) were expressed in E. coli BL21(DE3). The purified proteins were then labeled with biotin and the super streptavidin (SSA) biosensor was blocked with diluent. The biotin labeled protein sample was mixed with the sensor, and then the binding of the protein with a series of diluted non biotinylated protein was detected. At the same time, non-biotinylated protein was used as a control. The binding of biotinylated protein to a small molecule IMB-881 and the blocking of interaction were also detected by the same method. In the blank control, the biosensor without biotinylated protein was used to detect the serially diluted samples. The signal response constant was calculated by using steady analysis. The results showed that biotinylated LptC had a good binding activity with LptAfull and LptAno signal with KD value 2.9e⁻⁷±7.9e⁻⁸ and 6.0e⁻⁷±2.8e⁻⁸, respectively; biotinylated LptAno signal had a good binding activity with LptC, with a KD value of 9.6e⁻⁷±7.2e⁻⁸. All binding curves showed obvious fast binding and fast dissociation morphology. The small molecule compound IMB-881 can bind to LptA to block the interaction between LptA and LptC, but has no binding activity with LptC. In summary, we developed a method for detecting the LptA/LptC interaction based on the BLI technology, and confirmed that this method can be used to evaluate the blocking activity of small molecule blockers, providing a new approach for the screening of LptA/LptC interaction blockers.
Carrier Proteins ; Escherichia coli/metabolism* ; Escherichia coli Proteins/metabolism* ; Interferometry ; Membrane Proteins/metabolism*

Acetic acid is a common inhibitor present in lignocellulosic hydrolysate. Development of acetic acid tolerant strains may improve the production of biofuels and bio-based chemicals using lignocellulosic biomass as raw materials. Current studies on stress tolerance of yeast Saccharomyces cerevisiae have mainly focused on transcription control, but the role of transfer RNA (tRNA) was rarely investigated. We found that some tRNA genes showed elevated transcription levels in a stress tolerant yeast strain. In this study, we further investigated the effects of overexpressing an arginine transfer RNA gene tR(ACG)D and a leucine transfer RNA gene tL(CAA)K on cell growth and ethanol production of S. cerevisiae BY4741 under acetic acid stress. The tL(CAA)K overexpression strain showed a better growth and a 29.41% higher ethanol productivity than that of the control strain. However, overexpression of tR(ACG)D showed negative influence on cell growth and ethanol production. Further studies revealed that the transcriptional levels of HAA1, MSN2, and MSN4, which encode transcription regulators related to stress tolerance, were up-regulated in tL(CAA)K overexpressed strain. This study provides an alternative strategy to develop robust yeast strains for cellulosic biorefinery, and also provides a basis for investigating how yeast stress tolerance is regulated by tRNA genes.
Acetic Acid ; DNA-Binding Proteins/metabolism* ; Fermentation ; Leucine ; RNA, Transfer/genetics* ; Saccharomyces cerevisiae/metabolism* ; Saccharomyces cerevisiae Proteins/metabolism* ; Transcription Factors