A novel biosensor-based microarray assay for the visualized detection of CYP2C19 *2, *3, *4 and *5 polymorphisms.

BACKGROUND: A number of studies have indicated that the conversion of clopidogrel to its active metabolite is reduced in patients who carry the CYP2C19 *2, *3, *4 or *5 loss-of-function allele, resulting in decreased response of platelet to clopidogrel treatment and worse cardiovascular outcome. The aim of this study was to develop a novel biosensor-based microarray to visually detect CYP2C19 polymorphisms. METHODS: The target DNA was amplified from regions flanking the respective alleles using 5'-biotinylated reverse primer, and plasmids were prepared for the respective alleles. High stringency reversed hybridization, horseradish peroxidase-labeled streptavidin reaction, and color development, with multiple washes in different steps, were carried out and the results were recorded with an optical camera. The gene chips were tested for specificity, detection limit, intra- and inter-batch variations using the constructed plasmids. Finally, 88 clinical samples were assayed with this microarray as well as direct sequencing. RESULTS: The results could be seen with the naked eye. Concordance tests indicated that for alleles *2, *3, *4, and *5, the κ values between this assay and plasmids all reached 1.000. The detection limit was 5×10² cells/mL. Concordance test between direct sequencing and the microarray assay using 88 clinical samples gave rise to the κ value of 0.983, and p<0.01, indicating very high concordance. CONCLUSIONS: This novel biosensor-based microarray assay can amplify the signal in situ so that it can be detected by simple instruments or even the naked eyes. It is promising for clinical application in hospital laboratories.

Novel fluorescent risedronates: synthesis, photodynamic inactivation and imaging of Bacillus subtilis.

Novel fluorescently-labeled conjugates of risedronate were synthesized using an epoxide linker, enabling conjugation of risedronate via its pyridyl nitrogen with the aromatic succinimidyl esters. The compounds were characterized by using (1)H NMR, (13)C NMR, (31)P NMR, UV-vis and fluorescence emission spectroscopies. Biological activity assays showed that the conjugates 14 and 15 exhibited photodynamic inactivation of Bacillus subtilis (ATCC 6633) with 91% and 47% bacterial lethality at 10 µM upon visible light irradiation, respectively. Both 14 and 15 could be also used for fluorescence imaging of Bacillus subtilis.

A novel fluorogenic substrate for dinuclear Zn(II)-containing metallo-ß-lactamases.

In an effort to prepare a fluorogenic substrate to be used in activity assays with metallo-ß-lactamases, (6R,7R)-8-oxo-7-(2-oxo-2H-chromene-3-carboxamido)-3-((4-(2-oxo-2H-chromene-3-carboxamido)-phenylthio)methyl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (CA) was synthesized and characterized. CA exhibited a fluorescence quantum yield (φ) of 0.0059, two fluorescence lifetimes of 3.63×10(-10) and 5.38×10(-9)s, and fluorescence intensity that is concentration-dependent. Steady-state kinetic assays revealed that CA is a substrate for metallo-ß-lactamases (MßLs) L1 and CcrA, exhibiting Km and kcat values of 18µM and 5s(-1) and 11µM and 17s(-1), respectively.

Synthesis, characterization and activity of new phosphonate dipeptides as potential inhibitors of VanX.

VanX, a Zn(II)-dependent D-ala-D-ala dipeptidase, is essential for vancomycin resistance in Enterococcus faecium. The enzymatic activity of VanX was previously found to be inhibited competitively by 2-{[(1-aminoethyl) (hydroxy) phosphoryl]oxy} propanoic acid (1B). Here we report the synthesis and characterization of seven phosphonate dipeptide analogs of D-ala-D-ala with various substituent, the activity evaluation indicated that six of these phosphonate analogs inhibit VanX with IC(50) of 0.48-8.21mM. These data revealed a structure-activity relationship which is that the large substituent group on ß-carbon resulted in low binding affinity of the phonphonate analog to VanX. This information will be helpful to guide the design and synthesis of the tightly-binding inhibitors for VanX.

N-heterocyclic dicarboxylic acids: broad-spectrum inhibitors of metallo-ß-lactamases with co-antibacterial effect against antibiotic-resistant bacteria.

In an effort to identify novel, broad-spectrum inhibitors against the metallo-ß-lactamases (MßLs), several N-heterocyclic derivatives were tested as inhibitors of MßLs CcrA, ImiS, and L1, which are representative enzymes from the distinct MßL subclasses. Three N-heterocyclic dicarboxylic acid derivatives were competitive inhibitors of CcrA and L1, exhibiting K(i) values ≤2 µM, while only 2,4-thiazolidinedicarboxylic acid (1b) was a competitive inhibitor of ImiS. Two 2-mercapto-1,3,4-thiadiazole derivatives were noncompetitive inhibitors of CcrA and ImiS, exhibiting K(i) values <7 µM; however, these same compounds did not inhibit L1. Two 2-mercapto-1,3,4-triazole derivatives were shown not to inhibit any of the tested MßLs. The N-heterocyclic derivatives were tested for antibacterial activity by examining the MIC values for existing antibiotics in the presence/absence of these derivatives. Consistent with the steady-state inhibition data, the inclusion of three N-heterocyclic dicarboxylic acid derivatives resulted in lower MIC values when using Escherichia coli BL21(DE3) cells containing the CcrA or L1 plasmids or Klebsiella pneumoniae (ATCC 700603), while 1b was the only dicarboxylic acid derivative to lower the MIC value of E. coli cells containing the ImiS plasmid. Inclusion of the 2-mercapto-1,3,4-thiadiazole derivatives resulted in lower MIC values for E. coli cells containing ImiS or L1 plasmids; however, these derivatives did not alter the MIC values for K. pneumoniae or E. coli cells containing the L1 plasmid. None of the N-heterocyclic derivatives affected the MIC of two methicillin resistant Staphylococcus aureus (MRSA) strains. Taken together, these studies demonstrate that N-heterocyclic dicarboxylic acids 1a-c and pyridylmercaptothiadiazoles 2a,b are good scaffolds for future broad-spectrum inhibitors of the MßLs.

Novel conjugation of norvancomycin-fluorescein for photodynamic inactivation of Bacillus subtilis.

A simple and unique conjugation of norvancomycin-fluorescein (VanF) has been achieved. It was characterized by UV-vis and fluorescence spectra and confirmed by MALDI-TOF mass spectrum. The photodynamic assay indicated that VanF effectively inactivated the Gram-positive Bacillus subtilis (ATCC 6633) from clinic with inactivation rate of 30-70% within 1-7.5 µM. In vitro, VanF showed low antimicrobial activity with value of >128 µg/mL, binding affinity with value of 180 nM per 10(8) cells/mL against the bacteria strains. The fluorescence imaging showed that VanF could label the B. subtilis strain, but not the Escherichia coli (ATCC 25922), Enterococcus faecalis (ATCC 51299, VanD), and VRE strains from clinic.

Synthesis and activity study of phosphonamidate dipeptides as potential inhibitors of VanX.

In an effort to develop inhibitors of VanX, the phosphonamidate analogs of D-Ala-D-Ala dipeptides, N-[(1-aminoethyl) hydroxyphosphinyl]-glycine (1a), -alanine (1b), -valine (1c), -leucine (1d) and -phenylalanine (1e) were synthesized, characterized and evaluated using recombinant VanX. The crystal structure of the intermediate 6d was obtained (Deposition number: CCDC 839134), and structural analysis revealed that it is orthorhombic with a space group P2(1)2(1)2(1), the bond length of P-N is 1.62Å and angle of C-N-P is 123.6°. Phosphonamidate 1(a-e) showed to be inhibitors of VanX with IC(50) values of 0.39, 0.70, 1.12, 2.82, and 4.13mM, respectively, which revealed that the inhibition activities of the phosphonamidates were dependent on the size of R-substituent of them, with the best inhibitor 1a having the smallest substituent. Also, 1a showed antibacterial activity against Staphylococcus aureus (ATCC 25923) with a MIC value of 0.25 µg/ml.

Effect of miR-134 against myocardial hypoxia/reoxygenation injury by directly targeting NOS3 and regulating PI3K/Akt pathway.

PURPOSE: To reveal the function of miR-134 in myocardial ischemia. METHODS: Real-time PCR and western blotting were performed to measure the expression of miR-134, nitric oxide synthase 3 (NOS3) and apoptotic-associated proteins. Lactic dehydrogenase (LDH) assay, cell counting kit-8 (CCK-8), Hoechst 33342/PI double staining and flow cytometry assay were implemented in H9c2 cells, respectively. MiR-134 mimic/inhibitor was used to regulate miR-134 expression. Bioinformatic analysis and luciferase reporter assay were utilized to identify the interrelation between miR-134 and NOS3. Rescue experiments exhibited the role of NOS3. The involvement of PI3K/AKT was assessed by western blot analysis. RESULTS: MiR-134 was high regulated in the myocardial ischemia model, and miR-134 mimic/inhibitor transfection accelerated/impaired the speed of cell apoptosis and attenuated/exerted the cell proliferative prosperity induced by H/R regulating active status of PI3K/AKT signaling. LDH activity was also changed due to the different treatments. Moreover, miR-134 could target NOS3 directly and simultaneously attenuated the expression of NOS3. Co-transfection miR-134 inhibitor and pcDNA3.1-NOS3 highlighted the inhibitory effects of miR-134 on myocardial H/R injury. CONCLUSION: This present work puts insights into the crucial effects of the miR-134/NOS3 axis in myocardial H/R injury, delivering a potential therapeutic technology in future.

Effects of WIN55,212-2 on voltage-gated sodium channels in trigeminal ganglion neurons of rats.

OBJECTIVES: This study was carried out to investigate the effects of WIN55,212-2, a potential cannabinoid receptor agonist, on voltage-gated sodium currents I(Na) in cultured trigeminal ganglion neurons of rats, and to investigate whether the anti-nociceptive effects of cannabinoid receptor subtype 1 (CB1) were produced through its modulation on I(Na). METHODS: Whole cell patch clamp techniques were used to record I(Na) before and after WIN55,212-2 was perfused in cultured trigeminal ganglion neurons of rats. RESULTS: WIN55,212-2 (0.01 micromol/l) could enhance I(Na) slightly by 11.5 +/- 4.7% (n=7, p<0.05), and this effect could not be blocked by AM251, the CB1 receptor antagonist. However, WIN55,212-2 could inhibit I(Na) in concentration dependent manner at concentrations from 0.1 to 100 micromol/l. The inhibitory rates were 17.4 +/- 6.0, 22.5 +/- 7.8, 43.9 +/- 9.4 and 73.9 +/- 6.7% respectively by 0.1, 1, 10, 100 micromol/l WIN55,212-2, and the EC(50) was 17.8 micromol/l (n=7, p<0.05 or p<0.01). This inhibitory effect could be blocked partly by 1 micromol/l AM251 (n=7, p<0.05). WIN55,212-2 (0.01 micromol/l) shifted the active curve of I(Na) leftward slightly (n=7, p<0.05), but had no effect on its stable inactive curve (n=7, p>0.05). WIN55,212-2 (10 micromol/l) did not affect the active and stable inactive curves of I(Na) (n=7, p>0.05). CONCLUSION: WIN55,212-2 had bidirectional (two phases) effects on I(Na) in trigeminal ganglion neurons. It might act on different receptors, and the CB1 receptor participated in its modulation on I(Na).

[Selective knockdown of Angiotensin II receptor subtype 1a in rat vascular smooth muscle cells by RNA interference].

OBJECTIVE: To selectively knockdown the expression of Angiotensin II receptor subtype 1a (AT1aR) in rat vascular smooth muscle cells (VSMCs) by RNA interference and the sequential effects on cellular viability and proliferation. METHODS: The primary cultured rat aortic VSMCs were transfected by plasmids pAT1a-shRNA1 and pAT1a-shRNA2, each carrying an U6 promoter and an AT1a-specific shRNA-coding template sequence, or by a control plasmid pGenesil-Control (pCon) carrying a nonspecific shRNA-coding sequence. The mRNA and protein expressions of AT1a, AT2 were analyzed by semi-quantified RT-PCR and Western blot, respectively and normalized to the internal control gene beta-actin. Cellular viability and proliferation were determined with methylthiazoletetrazolium (MTT) assay. RESULTS: AT1a mRNA and protein were reduced by 82% and 69% by pAT1a-shRNA1, 77% and 56% by pAT1a-shRNA2, respectively while no change was found in pCon treated VSMCs. AT2 receptor level in VSMCs remains unchanged after various treatments. The A(490nm) values obtained by MTT measurements were similar among groups in the absence of Ang II but decreased significantly in pAT1a-shRNA1 and pAT1a-shRNA2 treated VSMCs in the presence of Ang II. CONCLUSION: RNA interference can selectively knockdown AT1a expression in cultured VSMCs and attenuate the Ang II induced cell proliferation. Future studies are warranted to explore the potential role of RNA interference on AT1 function and as a new gene therapy tool for cardiovascular diseases.

[Heterogeneity of action potential and ion currents in the left ventricular myocytes of the rabbit].

Experiments were performed to investigate the heterogeneity of the action potential and ion currents in left ventricular myocytes of the rabbit. Myocytes were isolated by enzymatic method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from the other region (midmyocardium, M) with a razor. Single cells in each region were obtained by gentle shaking and dispersing in a chamber filled with normal Tyrode's solution. The results showed that the action potential and the ion currents in the three layers were significantly different. M cells had a more pronounced spike-and-dome configuration, with a significantly larger phase 1 magnitude and plateau voltage. Action potential duration (APD) in M cells was longer than that in Epi or Endo cells. I(Ca, L) and I(to) in M cells were higher than those of Epi and Endo. On the contrary, I(K,s) in M cells was the minimum compared with those in the three LV walls. The differences in ion currents may well explain the heterogeneity of action potentials in M layers of the rabbit heart.

Effect of miR-134 against myocardial hypoxia/reoxygenation injury by directly targeting NOS3 and regulating PI3K/Akt pathway

Abstract Purpose To reveal the function of miR-134 in myocardial ischemia. Methods Real-time PCR and western blotting were performed to measure the expression of miR-134, nitric oxide synthase 3 (NOS3) and apoptotic-associated proteins. Lactic dehydrogenase (LDH) assay, cell counting kit-8 (CCK-8), Hoechst 33342/PI double staining and flow cytometry assay were implemented in H9c2 cells, respectively. MiR-134 mimic/inhibitor was used to regulate miR-134 expression. Bioinformatic analysis and luciferase reporter assay were utilized to identify the interrelation between miR-134 and NOS3. Rescue experiments exhibited the role of NOS3. The involvement of PI3K/AKT was assessed by western blot analysis. Results MiR-134 was high regulated in the myocardial ischemia model, and miR-134 mimic/inhibitor transfection accelerated/impaired the speed of cell apoptosis and attenuated/exerted the cell proliferative prosperity induced by H/R regulating active status of PI3K/AKT signaling. LDH activity was also changed due to the different treatments. Moreover, miR-134 could target NOS3 directly and simultaneously attenuated the expression of NOS3. Co-transfection miR-134 inhibitor and pcDNA3.1-NOS3 highlighted the inhibitory effects of miR-134 on myocardial H/R injury. Conclusion This present work puts insights into the crucial effects of the miR-134/NOS3 axis in myocardial H/R injury, delivering a potential therapeutic technology in future.

Novel fluorescent cephalosporins: synthesis, antimicrobial activity and photodynamic inactivation of antibiotic resistant bacteria.

Two novel fluorescent cephalosporins, TCA and TBCA, were synthesized and characterized by (1)H NMR, (13)C NMR, UV-vis, and fluorescence spectroscopies. Biological activity assays demonstrated that TCA inactivated a Klebsiella pneumonia strain that expressed extended-spectrum ß-lactamases. Incubation of 6 µM TCA with K. pneumonia cultures resulted in cell death for 84% of the cells after 126 J/cm(2) of light irradiation. In vitro, TCA exhibited a MIC = 0.5 µg/mL with Staphylococcus aureus. Kinetic evaluation revealed that TCA and TBCA were substrates for B1 and B3 subclass metallo-ß-lactamases. TBCA exhibited stronger binding affinities to the Gram-positive bacterial strains MRSA1, MRSA2, and S. aureus with value of 2.95-6.59 µM per 10(8) cells/mL.