Establishment of a human cell line with a surface display system for screening and optimizing Na+-taurocholate cotransporting polypeptide-binding peptides.

One of the most desirable targets for HBV medications is the sodium taurocholate cotransporting polypeptide (NTCP), an entry receptor for the hepatitis B virus (HBV). N-myristoylated preS1 2-48 (Myrcludex B or Hepcludex), an NTCP-binding peptide from the large surface protein of HBV, has been developed as the first-in-class entry inhibitor. However, its relatively large molecular weight contributes to increased immunogenicity and antibody production. As a result, it is preferable to look for an NTCP-binding peptide with a smaller size. To do this, we developed a human cell surface display strategy and screened peptides based on preS1-21. PreS1-21 (genotype D) was extended by 7 random amino acids and fused with mCherry and FasL transmembrane domain. The pooled constructs were transfected into HEK293 cells by using the transposon/transposase system to create a library displaying various peptides on the cell surface with red fluorescence. On the other hand, we expressed NTCP protein fused with EGFP on HEK293 and used the membrane lysate containing NTCP-GFP as the bait protein to select peptides with increased NTCP affinity. After 7 cycles of selection, the deep sequencing results revealed that some polypeptides were more than 1,000 times enriched. Further screening of the mostly enriched 10 peptides yields the peptide preS1-21-pep3. Replacing the preS1-21 sequence of preS1-21-pep3 with those from different genotypes demonstrated that the consensus sequence of genotype A-F had the best performance. The peptide (Myr-preS1-21-pep3) was synthesized and tested on the HepG2-NTCP cell model. The results showed that Myr-preS1-21-pep3 is approximately 10 times more potent than the initial peptide Myr-preS1-21 in preventing HBV infection. In conclusion, we developed a new strategy for screening peptides binding to membrane proteins and identified a new NTCP-binding peptide with a much smaller size than Hepcludex.

Identification of STAU1 as a regulator of HBV replication by TurboID-based proximity labeling.

The core promoter (CP) of hepatitis B virus (HBV) is critical for HBV replication by controlling the transcription of pregenomic RNA (pgRNA). Host factors regulating the activity of the CP can be identified by different methods. Biotin-based proximity labeling, a powerful method with the capability to capture weak or dynamic interactions, has not yet been used to map proteins interacting with the CP. Here, we established a strategy, based on the newly evolved promiscuous enzyme TurboID, for interrogating host factors regulating the activity of HBV CP. Using this strategy, we identified STAU1 as an important factor involved in the regulation of HBV CP. Mechanistically, STAU1 indirectly binds to CP mediated by TARDBP, and recruits the SAGA transcription coactivator complex to the CP to upregulate its activity. Moreover, STAU1 binds to HBx and enhances the level of HBx by stabilizing it in a ubiquitin-independent manner.

Nicotinamide N-Methyltransferase inhibits HBV replication by suppressing NR5A1 expression invitro.

Chronic hepatitis B virus (HBV) infection can lead to fibrosis, liver cirrhosis, and primary hepatocellular carcinoma. Investigating host factors that regulate HBV replication helps to identify antiviral targets. In the current study, we identified Nicotinamide N-Methyltransferase gene (NNMT) as a novel factor that regulates HBV transcription. NNMT is up-regulated at both the mRNA and protein levels in HepG2.2.15 cells compared to HepG2 cells. Overexpression of NNMT reduces HBV replication in several cell models, while knockdown of NNMT enhances HBV DNA levels. Mechanistically, NNMT suppresses HBV DNA replication by inhibiting HBV RNA transcription. The region required for the inhibitory effect of NNMT was narrowed to nt 1672-1708 in enhancer II by luciferase assays. On the other hand, ChIP assays and EMSA results showed that NNMT does not bind to this region substantially, either directly or indirectly. Next, a collection of hepatic nuclear receptor transcription factors was screened to determine whether they were affected by NNMT overexpression. NR5A1, a positive regulator of HBV replication, decreased significantly after NNMT overexpression. Collectively, the findings of this study shed light on the regulation of HBV transcription.

Crosstalk among Jasmonate, Salicylate and Ethylene Signaling Pathways in Plant Disease and Immune Responses.

Phytohormone crosstalk is crucial for plant defenses against pathogens and insects in which salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) play key roles. These low molecular mass signals critically trigger and modulate plant resistance against biotrophic as well as necrotrophic pathogens through a complex signaling network that even involves participation of other hormones. Crosstalk among SA, JA and ET is mediated by different molecular players, considered as integral part of these crosscommunicating signal transduction pathways. Recent progress has revealed that the positive versus negative interactions among those pathways ultimately enable a plant to fine-tune its defense against specific aggressors. On the other hand, pathogens have evolved strategies to manipulate the signaling network to their favour in order to intensify virulence on host plant. Here we review recent advances and current knowledge on the role of classical primary defense hormones SA, JA and ET as well as their synergistic and antagonistic interaction in plant disease and immune responses. Crosstalk with other hormones such as abscisic acid, auxin, brassinosteroids, cytokinins and melatonin is also discussed mainly in plant disease resistance. In addition to our keen focus on hormonal crosstalk, this review also highlights potential implication of positive and negative regulatory interactions for developing an efficient disease management strategy through manipulation of hormone signaling in plant.

Alprostadil liposome microsphere preparation stabilizes vascular plaques and inhibits intra-plaque inflammation.

BACKGROUND: Vulnerable plaques play an important role in the onset of sudden cardiac events and strokes. How to stabilize vulnerable plaques is still a challenge to medical science. Alprostadil is a biologically active substance with strong activity on vessel. Our study assessed the stabilizing effects of an alprostadil liposome microsphere preparation (ALMP) on vulnerable plaques in the brachiocephalic artery of apolipoprotein E (Apo E) knockout mice. METHODS: Seventy-two male Apo E-knockout mice were fed a high-fat diet beginning at eight weeks of age. At week 17, they were divided randomly into groups for treatment with a high dose (3.6 µg×kg(-1)×d(-1)) or low dose (1.8 µg×kg(-1)×d(-1)) of an ALMP, or 0.2 ml/d normal saline (control group). The drug was administered using a micro-capsule pump. Twenty weeks after drug administration, pathological changes in the vulnerable plaques within the brachiocephalic artery were assessed, and levels of anti-mouse monocyte/macrophage monoclonal antibody (MOMA-2) and superoxide anions in the plaques were detected using immunofluorescence. The soluble intercellular adhesion molecule-1 (ICAM-1) expression was measured by ELISA, and the expression of matrix metalloproteinase-9 (MMP-9) and CD40 mRNA was measured using RT-PCR. Thrombospindin-1 (TSP-1) expression was detected using Western blotting. RESULTS: Compared with the control group, ALMP treatment significantly reduced the plaque area in the brachiocephalic artery (P < 0.01), significantly lowered the contents of the lipid core (P < 0.01), significantly reduced the number of ruptured fibrous caps (P < 0.05), and increased the thickness of the fibrous cap and significantly reduced the incidence of intra-plaque hemorrhage (P < 0.05). ALMP treatment significantly reduced the expression of MOMA-2, superoxide anion, MMP-9, ICAM-1 and CD40 in the plaques (P < 0.01), decreased plasma ICAM-1 expression (P < 0.01), and increased the expression of TSP-1. CONCLUSIONS: Treatment with ALMP can stabilize vulnerable plaques by inhibiting inflammation.

[Antibiotic resistance of pathogens isolated from 181 children with complicated urinary tract infection].

OBJECTIVE: To investigate the distribution and antibiotic resistance of pathogens isolated from children with complicated urinary tract infection. METHODS: A retrospective analysis was performed on the distribution and antibiotic resistance of pathogens isolated from 181 children with complicated urinary tract infection (positive urine culture). The antibiotic resistance of common pathogens was determined by the antimicrobial susceptibility test. RESULTS: Gram-negative bacilli were the main pathogens (63.5%), and involved Escherichia coli (E.coli) of 42.0%. Gram-positive cocci accounted for 32.1%, and involved enterococci faecalis of 15.5%. Fungi infection was found in 4.4% of children. The resistance rate of E.coli to ampicillin was the highest (89.4%), but the rate decreased significantly by adding amoxicillin/clavulanic acid (34.2%). E.coli had a high resistance rate to cephazolin, ceftriaxone and cafalotin (>50%), but the resistance rate of E.coli to cefoperazone/sulbouam was significantly lower than other cephalosporins (P<0.01). E.coli was sensitive to imipenem and displayed a lower resistance rate to furadantin (<10%). The resistance rate of enterococci faecalis to rifampicin was high (78.3%), but was low to furadantin, vancomycin and linezolid (<10%). The multiresistant strains accounted for 77.4% of gram-negative bacilli. CONCLUSIONS: E.coli is the major pathogen in children with complicated urinary tract infection, and the enterococci-caused urinary tract infection has been increasing. These pathogens have a high antibiotic resistance, and most of them are multiresistant. Antimicrobial therapy should be based on the results of urine culture and antimicrobial susceptibility test.

[Comparison of immunomagnetic beads and hespan precipitation for isolation of mononuclear cells from umbilical cord blood].

OBJECTIVE: To compare the characteristics of immunomagnetic beads and hespan precipitation for isolation of mononuclear cells (MNCs) from umbilical cord blood and try to find a better isolation method for MNCs. METHODS: Fifteen umbilical cord blood samples from healthy parturiens were collected between December 2007 and March 2008. MNCs were isolated using hespan precipitation and CD133 immunomagnetic beads, respectively. MNCs were identified using the surface marker CD34 by flow cytometry on the 30th of primary culture. Growth conditions and morphologic changes of primary cells were observed by an inverted microscope. RESULTS: The number of MNCs from umbilical cord blood isolated by hespan precipitation (15.23 +/- 4.30 x 10(6)/mL) was significantly greater than that by CD133 immunomagnetic beads (0.066 +/- 0.027 x 10(6)/mL) (p<0.05). The MNCs isolated by hespan precipitation suspended at the culture medium and their growth was slow after passage. The growth of MNCs isolated by CD133 immunomagnetic beads was kept in a good condition. The CD34 positive rate of MNCs isolated by hespan precipitation and immunomagnetic beads was 10.1% and 0.5%, respectively. CONCLUSIONS: The hespan precipitation is an effective method for MNCs isolation from human umbilical cord blood, but with a cell growth condition below the mark. The MNCs isolated by CD133 immunomagnetic beads are in a high purity quotient.

[The effects of various beta-blockers on myocardial gap junction structure in rat with myocardial ischemia-reperfusion injury].

OBJECTIVE: To compare the effects of carvedilol, metoprolol and propranolol on myocardial gap junction (GJ) structure in rat with myocardial ischemia and reperfusion injury. METHODS: Rats were divided randomly into five groups: sham operation group (SO), myocardial ischemia and reperfusion group (IR), IR + carvedilol group (CV), IR + metoprolol group (MT), and IR + propranolol group (PP). The left anterior descending branch was ligated for 30 minutes and reperfused for 4 hours (IR). After 4 h reperfusion, the distribution and composition of gap junctional connexin 43 (CX43) were observed by immunofluorescence and laser scanning confocal microscopy (LSCM), and the quantification of CX43 was measured by LSCM. RESULT: Compared with SO group, IR resulted in abnormal distribution and composition of CX43-GJ and the impairment of CX43-GJ was significantly attenuated by CV, MT and PP treatments with the best effect observed in CV group (P<0.05 vs. MT and PP). CONCLUSION: These results suggest that beta-blockers, especially, carvedilol, could significantly attenuate IR induced CX43-GJ impairment.

[Role of gap junction in ischemic preconditioning].

OBJECTIVE: To investigate the role of gap junction in ischemic preconditioning (IPC). METHODS: Sprague-Dawley rats were subjected to a 30 min coronary artery occlusion followed by 4 h of reperfusion (I/R). Rats were divided into seven groups: I/R, IPC/R, IPC/R + 5-hydroxydecanoic acid (mitochondrial ATP sensitive potassium channel antagonist), I/R + diazoxide (mitochondrial ATP sensitive potassium channel agonist), I/R + 5-hydroxydecanoic acid + diazoxide, I/R + 18beta-glycyrrhetinic acid (gap junction blocker) and I/R + 18beta-glycyrrhetinic acid + 5-hydroxydecanoic acid. Hemodynamics and myocardial infarct size were measured and connexin43 phosphorylation and subcellular distribution were determined by quantitative immunoblotting and confocal immunofluorescence. RESULTS: Infarct size was reduced in IPC/R, I/R + diazoxide and I/R + 18beta-glycyrrhetinic acid group (13.34% +/- 7.87%, 11.02% +/- 2.24%, and 15.03% +/- 11.35%, respectively; P < 0.001 vs. I/R group: 45.81% +/- 7.91%). 5-hydroxydecanoic acid abolished the cardioprotective effects of IPC and diazoxide (46.57% +/- 5.36% and 47.36% +/- 3.17%; P > 0.05 vs. I/R) but not the effects of glycyrrhetinic acid (14.60% +/- 7.36%; P < 0.001 vs. I/R). Phosphorylation of connexin43 was significantly increased, dephosphorylation and connexin43 intracellular redistribution significantly decreased (Cx43 size in the cellular membrane 1.00% +/- 0.35% and 0.83% +/- 0.31%, P < 0.001 vs. I/R: 0.19% +/- 0.06%) by IPC and diazoxide and these effects could be abolished by 5-hydroxydecanoic acid. CONCLUSION: Ischemic preconditioning could reduce myocardial infarction size by activating mitochondrial ATP sensitive potassium channel and modulating connexin43 phosphorylation and internalization.

Clinical study on effect of Garlicin in stabilizing the carotid artery atherosclerotic plaque in patients with primary hypertension and coronary artery disease.

OBJECTIVE: To investigate the effect of garlicin in treating carotid artery atherosclerotic plaque (CAAP) in patients with primary hypertension and coronary heart disease (PHT-CHD). METHODS: Seventy-nine patients with PHT-CHD were randomly divided into the treated group (39 patients) treated with garlicin and fosinopril and the control group (40 patients) treated with fosinopril alone. The change of CAAP was evaluated by high frequency ultrasonic examination every six months, and the changes of intercellular adhesion molecule-1 (ICAM-1) and high sensitive C-reactive protein (hs-CRP) were measured by ELISA, with the observation proceeding for 52 weeks totally. RESULTS: By the end of the experiment, the number of complex plaques, Crouse integrals, intima-media thickness, serum ICAM-1 and hs-CRP were significantly lower in the treated group than those in the control group with significant difference (P < 0.05). CONCLUSION: Garlicin could stabilize CAAP to a certain extent and shows a definite vascular protective effect in patients with PHT-CHD.

[Bacterial pathogens and resistance patterns in community acquired pediatric urinary tract infection: experience of 152 cases].

OBJECTIVE: This study investigated the pathogen distribution and resistance patterns in childhood urinary tract infection in order to provide references for optimal use of antibiotics in the treatment of this disorder. METHODS: The clinical data of 152 children with community acquired urinary tract infection (urinary culture positive) between December 2001 and December 2004 were studied retrospectively. The bacterial pathogens of urinary tract infection and antimicrobial resistance were analyzed. RESULTS: Gram-negative bacilli was predominant pathogenic bacteria, accounting for 79.0% of the cases, and Escherichia coli (E. coli) was most commonly found (56.2%). Gram-positive cocci accounted for 18.4%, including 15.1% of Enterococcus faecalis. Fungi was rarely seen, accounting for only 2.6%. E. coli had a resistance rate of more than 50% to ampicillin, amoxicillin/clavulate, co-trimoxazole, cefradine, and fosomycin, but a very low resistance rate (< 4%) to 3rd generation cefalosporin, nitrofurantoi, azactom and amikacin. Enterococcus faecalis had a low resistance rate (< 20%) to ampicillin, vancomycin, penicillin, and nitrofurantoin. CONCLUSIONS: E. coli is the major pathogen in community acquired pediatric urinary tract infection, and Enterococcus has been become another important pathogen. Selection of antibiotics for the treatment of this disorder should base on drug-sensitive test results.

[Fosinopril but not metoprolol attenuated the increased matrix metallo-proteinases 9 expression at mRNA and protein levels of human umbilical vein endothelial cells exposed to oscillatory flow].

OBJECTIVE: To investigate the effect of fosinopril and metoprolol on metalloproteinases 9 (MMP9) expression of human umbilical vein endothelial cells (HUVECs) stimulated by oscillatory flow. METHODS: HUVECs were exposed to steady laminar flow or oscillatory flow, laminar flow or oscillatory flow plus various concentrations (1 x 10(-7) mol/L, 1 x 10(-5) mol/L) of fosinopril and metoprolol for 4 and 24 hours. MMP9 mRNA and protein expressions of HUVECs were determined by RT-PCR and Western blot, respectively. RESULTS: MMP9 expression at mRNA and protein levels were significantly increased in HUVECs exposed to oscillatory flow than that to laminar flow and these could be down-regulated by coincubation with fosinopril (1 x 10(-7) mol/L, 1 x 10(-5) mol/L, P < 0.01, P < 0.05, respectively) but not by co-incubation with metoprolol. CONCLUSION: Fosinopril can attenuate the increased MMP9 expression at mRNA and protein levels of HUVECs exposed to oscillatory flow.

[Effects and the mechanism of carvedilol on gap junctional intercellular communication in rat myocardium].

OBJECTIVE: To examine the effects of carvedilol on myocardial ischemia and reperfusion injury and on gap junctional intercellular communication (GJIC). METHODS: The left coronary artery was occluded for 30 min and reperfused for 4 h. The activity of creatine phosphokinase (CK), lactate dehydrogenase (LDH) and the infarct size were measured. Isolated buffer-perfused hearts were divided randomly into four groups, sham operation (SO), myocardial ischemia and reperfusion (IR), carvedilol (CV) and heptanol (a gap junctional inhibitor) (HT). The effect of carvedilol on GJIC was measured by a modification of Scrape-loading and dye transfer method, and the state of CX43 phosphorylation was evaluated by Western blot. RESULTS: Compared with the SO group, Increased CK, LDH and infarct size were found in the IR group after 4 h reperfusion. GJIC in the IR group was not inhibited, but dephosphorylated CX43 was increased after 30 minutes of ischemia. Carvedilol decreased CK, LDH and infarct size compared with the IR rats; after 30 minutes of ischemia, both carvedilol and heptanol significantly reduced the GJIC, associated with a significant augmentation of dephosphorylated CX43. CONCLUSIONS: These results suggest that carvedilol reduces GJIC during ischemia presumably by dephosphorylating Cx43, which may be one of the mechanisms of lessening myocardial ischemia-reperfusion injury.