Polyhedral {Ag12} and {Ag16} Clusters: Synthesis, Structural Characterization and Third-Order Nonlinear Optical Properties.

Two polyhedral silver-thiolate clusters, [S@Ag16(Tab)10(MeCN)8](PF6)14 (Ag16) and [Ag12(Tab)6(DMF)12](PF6)12 (Ag12), were synthesized by using electroneutral Tab species as protective ligands (Tab = 4-(trimethylammonio)benzenethiolate, DMF = N,N-dimethylformamide, MeCN = acetonitrile). Ag16 has a decahedral shape composed of eight pentagon {Ag5} units and two square {Ag4} units. The structure of Ag12 is a cuboctahedron, a classical Archimedean structure composed of six triangular faces and eight square faces. The former configuration is discovered in silver-thiolate cluster for the first time, possibly benefited from the more flexible coordination between the Tab ligand and Ag+ facilitated by the electropositive -N(CH3)3 substituent group. Third-order nonlinear optical studies show that both clusters in DMF exhibit reverse saturate absorption response under the irradiation of 532 nm laser.

Finite-Key Analysis for Quantum Key Distribution with Discrete-Phase Randomization.

Quantum key distribution (QKD) allows two remote parties to share information-theoretic secret keys. Many QKD protocols assume the phase of encoding state can be continuous randomized from 0 to 2π, which, however, may be questionable in the experiment. This is particularly the case in the recently proposed twin-field (TF) QKD, which has received a lot of attention since it can increase the key rate significantly and even beat some theoretical rate-loss limits. As an intuitive solution, one may introduce discrete-phase randomization instead of continuous randomization. However, a security proof for a QKD protocol with discrete-phase randomization in the finite-key region is still missing. Here, we develop a technique based on conjugate measurement and quantum state distinguishment to analyze the security in this case. Our results show that TF-QKD with a reasonable number of discrete random phases, e.g., 8 phases from {0,π/4,π/2,…,7π/4}, can achieve satisfactory performance. On the other hand, we find the finite-size effects become more notable than before, which implies that more pulses should be emit in this case. More importantly, as a the first proof for TF-QKD with discrete-phase randomization in the finite-key region, our method is also applicable in other QKD protocols.

The analgesic action of larixyl acetate, a potent TRPC6 inhibitor, in rat neuropathic pain model induced by spared nerve injury.

BACKGROUND: Neuropathic pain is a debilitating status that is insusceptible to the existing analgesics. It is important to explore the underlying pathophysiological changes and search for new pharmacological approaches. Transient receptor potential canonical 6 (TRPC6) is a mechanosensitive channel that is expressed by dorsal root ganglia and glial cells. It has been demonstrated that this channel in dorsal root ganglia plays essential roles in the formation of mechanical hyperalgesia in neuropathic pain. Recent pharmacological screening suggests that larixyl acetate (LA), a main constituent of larch resin, is able to selectively inhibit TRPC6 function. But whether LA is effective in treating neuropathic pain remains unknown. We investigated the efficacy of LA in rat neuropathic pain model, examined its effects on central neuroinflammation, and explored the possible molecular mechanisms by targeting the spinal dorsal horn. METHODS: Spared nerve injury (SNI) was conducted in Sprague-Dawley rats. Mechanical hypersensitivity and cold allodynia before and after single and multiple i.t. applications of LA at the dose of 3, 10, and 30 µM were evaluated by von Frey filament and acetone tests, respectively. Western blot, immunohistochemical, and immunocytochemical stainings were employed to examine the level and expression feature of ionized calcium-binding adaptor molecule 1 (Iba-1), glial fibrillary acidic protein (GFAP), TRPC6, and phosphorylated p38 kinase. The changes of cytokine concentrations, including that of TNF-α, IL-1ß, IL-6, and IL-10, were also assessed by multiplex analysis. TRPC6 antisense strategy was finally adopted to investigate the action mechanisms of LA. RESULTS: Single application of LA on day 5 post injury caused dose-dependent inhibition of mechanical allodynia with the ED50 value of 13.43 µM. Multiple applications of LA at 30 µM not only enhanced the analgesic efficacy but also elongated the effective duration without obvious influences on animal locomotor activities. Single and multiple administrations of LA at 30 µM played similar but weaker inhibitory effects on cold allodynia. In addition to behavioral improvements, multiple applications of LA for 6 days dose-dependently inhibited the upregulation of Iba-1, TNF-α, IL-1ß, and IL-6, whereas had no obvious effects on the levels of GFAP and IL-10. Combined Western blot and immunostaining assays revealed that the expression of TRPC6 was significantly increased in both spinal dorsal horn after nerve injury and the cultured microglia challenged by LPS, which was however suppressed by the addition of LA at 30 µM or 10 µM, respectively. Further knockdown of TRPC6 with antisense oligodeoxynucleotide produced prominent analgesic effects in rats with SNI, accompanied by the reduced phosphorylation level of p38 in the microglia. CONCLUSIONS: These data demonstrate that i.t. applied LA exhibits analgesic and anti-inflammatory action in neuropathic pain. The action of LA involves the suppression of TRPC6 and p38 signaling in the microglia. LA may be thus a promising pharmacological candidate for the treatment of intractable chronic pain.

Synergistic upregulation of NONO and PSPC1 regulates Sertoli cell response to MEHP via modulation of ALDH1A1 signaling.

Members of the Drosophila behavior/human splicing protein family, including splicing factor proline/glutamine rich (SFPQ), non-POU domain-containing octamer-binding protein (NONO), and paraspeckle protein component 1 (PSPC1), are abundantly expressed in testicular Sertoli cells (SCs), but their roles remain obscure. Here, we show that treatment with mono-(2-ethylhexyl) phthalate (MEHP), a well-known SC toxicant, selectively stimulates the expression levels of NONO and PSPC1. Simultaneous inhibition of NONO and PSPC1 expression in SCs enhances MEHP-induced oxidative stress and potentiates SC death. Mechanistically, NONO and PSPC1 transcriptionally activate aldehyde dehydrogenase 1 (Aldh1a1), by synergistically binding to the distinct CCGGAGTC sequence in the Aldh1a1 promoter. Together, the NONO/PSPC1-ALDH1A1 cascade may serve as an indispensable defense mechanism against MEHP insult in SCs.

Morphological Identification of TRPC7 in Cardiomyocytes From Normal and Renovascular Hypertensive Rats.

OBJECTIVE: We aimed to investigate the expression characteristics of transient receptor potential canonical 7 (TRPC7) in normal and hypertrophic cardiac myocytes. METHODS: The 2-kidney 1-clip (2K1C) method was used to induce renovascular hypertension. Losartan, the potent inhibitor of angiotensin II (Ang II) receptor, was applied to the drinking water of 2K1C rats to inhibit Ang II-mediated responses. TRPC7 expression was examined by immunohisto/cytochemistry and Western blot analyses in normal and hypertrophic hearts. The expression level of protein kinase C (PKC), a negative regulator of TRPC7 channel in in vitro study, was also evaluated. RESULTS: In normal rat ventricles, strong TRPC7 immunoreactivity was distributed in the surface sarcolemma of cardiomyocytes, and a moderate but striated TRPC7 immunoreactivity was also detected in the subcellular regions. The 2K1C operation caused significant hypertension and cardiac hypertrophy as demonstrated by respective biophysical or biochemical assays. At this stage, expression of TRPC7 was significantly downregulated at both tissue and cell levels, whereas that of PKC was upregulated. Further analysis revealed a negative correlation between TRPC7 and PKC expression patterns. Oral application of losartan ameliorated the extent of experimentally induced hypertension and cardiac hypertrophy. Simultaneously, it effectively reversed the downregulation of TRPC7 and mildly antagonized the upregulation of PKC. CONCLUSIONS: Taken together, these results for the first time show that TRPC7 localizes in the surface and tubular sarcolemma of cardiomyocytes in normal adult rats and its expression significantly decreases in hypertrophied cardiomyocytes from renovascular hypertensive rats. TRPC7 may thus play a significant role in normal physiological settings in the heart.

Erratum to: Progressive changes of orexin system in a rat model of 6-hydroxydopamine-induced Parkinson's disease.

[This corrects the article DOI: 10.1007/s12264-010-0410-9.].

Progressive changes of orexin system in a rat model of 6-hydroxydopamine-induced Parkinson's disease.

OBJECTIVE: Sleep disturbance, which is characterized by excessive daytime sleepiness and sleep attacks, is frequently observed in patients with Parkinson's disease (PD). Loss of orexin neurons in hypothalamus and the resultant decreased level of orexin in cerebrospinal fluid (CSF) found in narcolepsy patients may also play an essential role in the pathogenesis of sleep disturbance. The present study aimed to investigate the possible changes in the orexin system during PD progression. METHODS: After the establishment of a rat PD model by injecting 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle, the numbers of orexin-A- and tyrosine hydroxylase (TH)-positive neurons, and the levels of orexin-A fibers and orexin-A in CSF were examined by immunohistochemistry and ELISA assay, respectively. RESULTS: Compared to the TH-containing neurons that exhibited fast degeneration in response to 6-OHDA, orexin-A-containing neurons were less sensitive to 6-OHDA. The number of orexin-A-positive neurons began to decrease at day 21 after operation, and at day 49, it decreased by 30% of the initial level. The orexin-A level in CSF of PD rats did not show any obvious fluctuations compared to the control, and there was no obvious reduction in the density of orexin-A-positive fibers in brain areas such as tuberomammillary nucleus. CONCLUSION: These results reveal for the first time the dynamic changes of orexin system during the progression of PD. This may provide valuable information for drug development to reverse the loss of orexin neurons and sleep disturbance in PD patients.

Synergistic actions of diacylglycerol and inositol 1,4,5 trisphosphate for Ca2+-dependent inactivation of TRPC7 channel.

AIM: The aim of the present study was to explore the mechanism for the Ca2+- dependent inactivation of the canonical transient receptor potential (TRPC) 7 channel expressed in human embryonic kidney 293 cells. METHOD: The whole-cell patch-clamp technique was used in the study. RESULTS: With Ca2+-free external solution, the perfusion of 100 micromol/L carbachol to, or dialysis of the cell with 100 micromol/L guanosine 5'-3-O-(thio)triphosphate (GTPgammaS), induced large inward currents, respectively. These currents were rapidly inhibited by the addition of 1 mmol/L Ca2+ into the bath, and recovery from this inhibition was only partial after the Ca2+ removal, unless vigorous intracellular Ca2+ buffering with 10 mmol/L 1,2 bis(2- aminophenoxy)ethane-N,N,No,No-tetraacetic acid (BAPTA) (plus 4 mmol/L Ca2+) was employed. In contrast, the current induced by a membrane-permeable analog of diacylglycerol (DAG), 1-oleoyl-2-acetyl-sn-glycerol (OAG; 100 micromol/L) did not undergo the inhibition persisting after Ca2+ removal. Interestingly, the inclusion of inositol 1,4,5 trisphosphate (IP3; 100 micromol/L) in the patch pipette rendered the OAG-induced current susceptible to the persistent Ca2+-mediated inhibition independent of the IP3 receptor in the majority of the tested cells, as evidenced by the inability of heparin and thapsigargin in reversing the effect of IP3. CONCLUSION: The present results suggest that Ca2+ entry via the activated TRPC7 channel plays a critical role in inactivating the channel where the cooperative actions of DAG and IP3 are essentially involved.

[Effect of a hypothetical gene Af116609 on multi-drug resistance of gastric cancer cells].

OBJECTIVE: To investigate the effect of gene Af116609 on gastric cancer multi-drug resistance (MDR) by introducing it into gastric cancer multi-drug resistant (MDR) cell line SGC7901/VCR. METHODS: Gene Af116609 was cloned from SGC7901/VCR by RT-PCR and its differential expression between gastric cancer MDR cells and its parental cells was displayed by Northern blot. The gene was introduced to gastric cancer cells by transfection of recombinant eukaryotic expression vector by electroporation. MTT assay in vitro was applied to investigate its effect on multi-drug resistance phenotype of gastric cancer cells. RESULTS: The full length CDS of gene Af116609, as long as 327 bp, was cloned from gastric cancer MDR cell line SGC7901/VCR and its sequence was coincident with the hypothetical gene Af116609 in GenBank. It was overexpressed in MDR cells than its parental cells at mRNA level. In the MTT assay in vitro, the drug sensitive cells transfected with sense eukaryotic expression vector showed upregulated targeted gene, with increased resistance to vincristine, 5-fliorouracil and arabinoside, and decreased resistance to adriamycin, but no influence on resistance to methotrexate. However, the drug resistant cells transfected with anti-sense eukaryotic expression vector, showed down regulated targeted gene, with less resistance to all the five anticancer drugs to different degrees. CONCLUSION: Gene Af116609 is related to MDR phenotype of gastric cancer cells and may become a candidate molecular target to reverse the MDR of gastric cancer.

[The overexpression of prion protein in drug resistant gastric cancer cell line SGC7901/ADR and its significance].

OBJECTIVE: To investigate the overexpression of prion protein (PrP) in drug-resistant gastric cancer cell line SGC7901/ADR and its role in multidrug resistance in gastric cancer. METHODS: (1) The expression of PrP in SGC7901/ADR, SGC790/VCR and their parental cell line SGC7901 was detected with Northern and Western blot at the mRNA and protein level. (2) Eukaryotic sense and antisense expression vector were constructed based on DNA recombination technology and (3) introduced into SGC7901 and SGC7901/ADR cell lines through electroporation. (4) The accumulation and retention of ADR in transiently transfected cells were detected by flow cytometry. RESULTS: (1) Northern and western blot suggested significantly higher expression of PrP in SGC7901/ADR and SGC7901/VCR than that in SGC7901. (2) 48 hours after the vectors transfection, the average fluorescence intensity of Adr in transfected cells were detected. The accumulation intensity were 8.9 +/- 0.7 in BS, 6.6 +/- 0.3 in PS and 7.5 +/- 0.6 in PA. The retention intensity were 9.3 +/- 0.6 in SGC7901, 5.9 +/- 0.5 in PS and 7.1 +/- 0.5 in PA. There were significant difference between PS and BS with P < 0.01, as well as RA and BA with P < 0.01. These data suggested that PrP gene could affect the drug accumulation in gastric cancer cells after its transfected into cells. CONCLUSION: PrP was highly expressed in gastric cancer cell lines SGC7901/ADR and SGC7901/VCR. Overexpression of PrP had certain effect on drug accumulation in gastric cancer cells.

Effect of ZNRD1 gene antisense RNA on drug resistant gastric cancer cells.

AIM: To investigate the expression level of ZNRD1 gene in gastric cancer cells SGC7901 and gastric cancer MDR (multidrug resistant) cells SGC7901/VCR, and to observe the drug sensitizing and proliferation effect of ZNRD1 antisense nucleic acid transduction on SGC7901/VCR cells. METHODS: Amplification of sequences encoding ZNRD1 from SGC7901/VCR cDNA by PCR. The levels of ZNRD1 mRNA expression were demonstrated using semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Eukaryotic expression vector pcDNA3.1-anti ZNRD1 was constructed and transfected into SGC7901/VCR cells by lipofectamine. Immunochemical method was used to detect the expression of protein in SGC7901/VCR cells and transfectants. The cell cycle alteration and the intracellular adriamycin (ADM) accumulation were observed by FACS. Growth curve and drug sensitization of cells for vincristine (VCR) were analyzed with MTT assay. RESULTS: We cloned the open reading frame of full-length ZNRD1. The expression of ZNRD1 showed higher in SGC7901/VCR than in SGC7901 cells. The antisense ZNRD1 drug-resistant clones were selected after gene transfection. Immunochemical results showed that the expression level of ZNRD1 protein was lower in anti ZNRD1-SGC7901/VCR cells than that in non-transfectants. Comparing to SGC7901/VCR and pcDNA3.1-SGC7901/VCR, anti ZNRD1-SGC7901/VCR showed gradually accumulated in G(1) phase, with a concomitant decrease of cell population in S phase. FACS also suggested intracellular ADM accumulation increased 2fold in SGC7901/VCR cells after transfected with antisense ZNRD1. MTT assay showed that transfectants cells proliferation was lagged and more sensitive to VCR than non-transfectants. CONCLUSION: ZNRD1 gene displayed highly expression in VCR resistant gastric cancer cells. Expression of ZNRD1 protein was effectively blocked in anti ZNRD1-SGC7901/VCR cells by gene transfection. ZNRD1 antisense nucleic acid transfection sensitized drug resistant gastric cancer cells to VCR, increased ADM accumulation and inhibited the cells proliferation. ZNRD1 antisense RNA transduction could reverse the MDR of human drug-resistant gastric cancer cell SGC7901/VCR to a degree.

[Differential expression of RPL6/Taxreb107 in drug resistant gastric cancer cell line SGC7901/ADR and its correlation with multiple-drug resistance].

OBJECTIVE: To investigate the differential expression of RPL6/Taxreb107 between drug-resistant gastric cancer cell line SGC7901/ADR and gastric cancer cell line SGC7901 as well as its correlation with multiple-drug resistance (MDR) in gastric cancer cells. METHODS: Total RNA was extracted from SGC7901 and SGC77901/ADR, with internal control RT-PCR, Northern blot, gene cloning and expression, construction of eukaryotic expression vector, gene transfection by electroporation. The accumulation and retention of ADR in transiently transfected cell was detected by flow cytometry. RESULTS: The internal control RT-PCR and Northern blot showed high RPL6/Taxreb107 expression in SGC7901/ADR cell line. Sense and antisense eukaryonic expression vectors demonstrated by double enzyme digestion were successfully transfected into gastric cancer cell line SGC7901 and SGC7901/ADR respectively by electroporation. The accumulation and retention of ADR detected 48 hours after transfection showed that RPL6 gene had shown effect on drug resistance in gastric cancer cell. CONCLUSION: The high expression of RPL6/Taxreb107 in drug resistant gastric cancer cell shows its correlation with multiple-drug resistance in gastric cancer.