Effects of host proteins interacting with non-structural protein nsp9 of porcine epidemic diarrhea virus on viral replication / 生物工程学报

Porcine epidemic diarrhea virus (PEDV) is a highly pathogenic virus that can cause acute intestinal infectious diseases in both piglets and fattening pigs. The virus encodes at least 16 non-structural proteins, including nsp9, which has been shown to bind to single-stranded RNA. However, its function and mechanism remain unclear. In this study, we aimed to identify potential host proteins that interact with PEDV nsp9 using immunoprecipitation combined with mass spectrometry. The interactions were then confirmed by co-immunoprecipitation (Co-IP) and confocal laser scanning fluorescence techniques. The results showed that nsp9 interacts with HSPA8, Tollip, HSPA9 and TOMM70. Among them, overexpression of HSPA8 resulted in caused first upregulated and then down-regulated expression of nsp9, and promoted the proliferation of PEDV. Overexpression of Tollip significantly upregulated the expression of nsp9 and inhibited the proliferation of PEDV. Overexpression of TOMM70 significantly reduced the expression of nsp9, but did not show significant effect on the proliferation of PEDV. Overexpression of HSPA9 did not show significant effect on the expression of nsp9 and the proliferation of PEDV. These findings may facilitate further investigating the role of nsp9-interacting proteins in PEDV infection.

CircRNA-SCAF8 promotes vascular endothelial cell pyroptosis by regulating the miR-93-5p/TXNIP axis / 浙江大学学报·医学版

OBJECTIVES@#To investigate the role and mechanism of circRNA-SR-related CTD associated factor 8 (SCAF8) in regulating endothelial cell pyroptosis in high glucose environment.@*METHODS@#Human umbilical vein endothelial cells (HUVECs) were cultured and divided into six groups. The normal control group and high glucose control group were cultured in cell culture medium with 5 and 33 mmol/L glucose, respectively. The RNA control group, circRNA-SCAF8 inhibition group, miR-93-5p overexpression group and miR-93-5p inhibition group were added with non-functional siRNA, circRNA-SCAF8 inhibitor, miR-93-5p overexpression molecule and miR-93-5p inhibitor in high glucose environment, respectively. Cell viability and pyroptosis were detected by cell counting kit-8 (CCK-8) assay, flow cytometry and Hoechst 33342/propidium iodide fluorescence double staining. Western blotting and enzyme-linked immunosorbent assay were used to detect the expression of pyroptosis-related factors including apoptosis-associated speck-like protein containing a CARD (ASC), cysteine aspartic acid specific protease-1 (caspase-1) and Gasdermin D (GSDMD), NOD like receptor protein 3 (NLRP-3), thioredoxin interacting proteins (TXNIP), IL-18 and IL-1β. The expression of circRNA-SCAF8, miR-93-5p and TXNIP was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Fluorescence in situ hybridization (FISH) was used to locate circRNA-SCAF8 and miR-93-5p. Dual luciferase assay was used to verify the targeted regulatory relationship between miR-93-5p and upstream and downstream molecules.@*RESULTS@#Compared with the RNA control group, the cell survival rate of circRNA-SCAF8 inhibition group and miR-93-5p overexpression group increased (both P<0.01), the pyroptosis decreased (both P<0.01), and the expressions of pyroptosis-related factors such as TXNIP, NLRP-3, caspase-1, GSDMD, ASC, IL-18 and IL-1β were significantly decreased (all P<0.05). The expression of miR-93-5p was significantly increased after inhibition of circRNA-SCAF8 (P<0.01), and the expression of circRNA-SCAF8 tended to decrease after overexpression of miR-93-5p, but with no statistical significance (P>0.05). Dual luciferase assay showed that miR-93-5p downre-gulated circRNA-SCAF8 expression by binding to the 3 ´ UTR region of circRNA-SCAF8, and miR-93-5p downregulated TXNIP expression by binding to the 3 ´ UTR region of TXNIP. FISH showed that circRNA-SCAF8 and miR-93-5p were both located in the cytoplasm and were highly associated in the cells. qRT-PCR showed that the relative expression of TXNIP increased or decreased after overexpression or inhibition of miR-93-5p compared with the RNA control group, respectively (both P<0.05), suggesting that miR-93-5p could regulate TXNIP gene expression.@*CONCLUSIONS@#CircRNA-SCAF8/miR-93-5p/TXNIP axis is involved in the regulation of pyroptosis in HUVECs under high glucose.

DJ-1 interacting proteins analyzed by tandem affinity purification mass spectrometry / 中国医师杂志

Objective:RNA interference technology (siRNA) was used to inhibit the expression of DJ-1 gene in lung squamous cell carcinoma HTB-182 cells, then, tandem affinity purification mass spectrometry (TAP-MS) was performed to screen the interacting proteins of DJ-1 in lung cancer cell line of HTB-182.Methods:The siRNA lentivirus vector targeting DJ-1 gene was constructed to infect HTB-182 cells (DJ-1 siRNA group), and the lentivirus vector control group (control siRNA group) and blank control group were established. The expression level of DJ-1 protein was detected by Western blot, and the endogenous DJ-1 protein silenced si-DJ-1-HTB-182 cells were established. The specific primers of DJ-1 were designed, and the DJ-1 expression plasmid pNTAP-DJ-1 with streptomycin binding peptide label (SBP) and calmodulin binding peptide label (CBP) was constructed. The cell line DJ-1 siRNA HTB-182 was stably transfected with liposome, and the positive clones were screened by G418. The positive clones were verified by Western blot, and the interacting proteins of DJ-1 were found by TAP-MS.Results:The protein expression of DJ-1 in DJ-1 siRNA interference group was significantly lower than that in empty plasmid group and blank control group ( P<0.05); HTB182 cell line stably expressing pNTAP-DJ-1 plasmid was successfully constructed; Three proteins interacting with DJ-1 were screened by TAP-MS: cytokeratin 1 (keratin 1), cytokeratin 10 (keratin 10) and NADPH oxidase activating protein P47 (P47 Px). Conclusions:Keratin 1, Keratin l0 and P47 Px protein may be DJ-1 interactions protein.

Identification of protein that interacts with adhesion protein of Mycoplasma genitalium from T7-phage display cDNA library / 中国免疫学杂志

Objective:To screen and identify the protein that interacts with the adhesion protein of Mycoplasma genitalium (MgPa)from T7-phage display cDNA library of human uroepithelial cells(SV-HUC-1).Methods:Recombinant adhesion protein of My-coplasma genitalium(rMgPa)was used as target molecule to biopan the T7 phage display cDNA library of SV-HUC-1 cell,the selected positive clones were analysed using DNA sequencing and BLAST analysis and identified by means of indirect ELISA,Dot immunoblot and Far-western blot.Results:After four rounds of biopanning,positive phages were obviously enriched.According to the results of DNA sequencing and BLAST analysis,the selected randomly 32 positive clones included 7 kinds different sequences,of which the number of RPL35 repeats was the most.The results of indirect ELISA,Dot immunoblot and Far-western blot showed that 7 representative phages could bind specifically with rMgPa.Conclusion:60S ribosomal protein L35(RPL35) may be the interacting protein of MgPa,which lays the experimental foundation for understanding the function of MgPa and the pathogenesis of Mycoplasma genitalium.

Actin-interacting and flagellar proteins in Leishmania spp: bioinformatics predictions to functional assignments in phagosome formation

Several motile processes are responsible for the movement of proteins into and within the flagellar membrane, but little is known about the process by which specific proteins (either actin-associated or not) are targeted to protozoan flagellar membranes. Actin is a major cytoskeleton protein, while polymerization and depolymerization of parasite actin and actin-interacting proteins (AIPs) during both processes of motility and host cell entry might be key events for successful infection. For a better understanding the eukaryotic flagellar dynamics, we have surveyed genomes, transcriptomes and proteomes of pathogenic Leishmania spp. to identify pertinent genes/proteins and to build in silico models to properly address their putative roles in trypanosomatid virulence. In a search for AIPs involved in flagellar activities, we applied computational biology and proteomic tools to infer from the biological meaning of coronins and Arp2/3, two important elements in phagosome formation after parasite phagocytosis by macrophages. Results presented here provide the first report of Leishmania coronin and Arp2/3 as flagellar proteins that also might be involved in phagosome formation through actin polymerization within the flagellar environment. This is an issue worthy of further in vitro examination that remains now as a direct, positive bioinformatics-derived inference to be presented.

The function of C-terminal tail of opioid receptors and the proteins interaction with C-terminal tail of opioid receptors / 中国药理学通报

The C-terminal tail of opioid receptor is important for opioid receptor phosphorylation,desensitization and internalization after opioid agonists treatment.The C-terminal point mutant and truncated mutant of amino acid residues of ?opioid receptors such as T394A,T383A,T357A,S355A affect the function of the opioid receptor obviously.The identical results could be seen in the C-terminal point mutant S363A of ?opioid receptor and S369A of ?opioid receptor.It is well known that opioid receptor requires interaction with other proteins for function,regulation and trafficking.Although proteins such as PPL,FilaminA,PLD2,PKCI,GASP and EBP50/NHERF have been identified to interact with C-terminals of opioid receptors,the role of interaction of these proteins with opioid receptor in the dependence,tolerance and addiction of opioids is dubious.Therefore,looking for the proteins specifically interacting with the C-terminals of opioid receptor may be important to understand the mechanism of opioids addiction.

Screening of proteins interacting with hepatitis C virus core protein from T7-phage display library / 第三军医大学学报

Objective To screen and identify proteins that interact with the hepatitis C virus core protein by means of T7-phage display system. Methods The hepatitis C virus core protein was expressed by prokaryotic expression and used as selected molecule to biopan the T7 human liver cDNA library. The selected positive clones were identified by DNA sequence and analyzed with BLAST program in GenBank. Results After BLAST in all positive clones, one protein--Smad interacting protein 1 (SIP1) was found to interact with the hepatitis C virus core protein. Conclusion T7-phage display system is a convenient, rapid and effective method for screening interacting proteins.

Screening of proteins interacting with the Hepatitis B Virus PreS1 protein from T7-Phage display library / 重庆医科大学学报

Objective:To screen and identify proteins that interact with the hepatitis B virus PreS1 protein by means of T7-phage display system. Method:Hepatitis B virus PreS1 protein was expressed by prokaryotic expression and used as selected molecule to biopan the T7 select human liver cDNA library,the selected positive clones were identified by DNA sequence and analyzed with BLAST program in GenBank. Result:After BLAST in all positive clones,one protein:Cytochrome c Oxidase Subunit I(COX1)was found to interact with the hepatitis B virus PreS1 protein. Conclusion:T7-phage display system is a convenient,rapid and effective method for screening interacting proteins. This results will provide important evidences for studying the pathogenesis and mechanism of HBV.