Calcitonin gene-related peptide regulates mitogen-activated protein kinase pathway to decrease transforming growth factor β1-induced hepatic plasminogen activator inhibitor-1 mRNA expression in HepG2 cells

Transforming growth factor (TGF) β1-induced plasminogen activator inhibitor (PAI)-1 is one of factors associated with the development of hepatic fibrosis. Calcitonin gene-related peptide (CGRP) shows hepatoprotective effect during hepatic injuries, including fibrosis. However, the effects of CGRP on PAI-1 expression induced by TGFβ1 are unknown. In this study, we investigated the effect of CGRP on TGFβ1-induced PAI-1 expression and its regulatory mechanisms in HepG2 cells. CGRP inhibited TGFβ1-induced PAI-1 expression. H89, a protein kinase A inhibitor, abolished the inhibition of TGFβ1-induced PAI-1 expression by CGRP. TGFβ1 activated mitogen-activated protein kinase (MAPK), including extracellular signal-regulated kinase, c-jun NH₂-terminal kinase, and p38, and this activation was abolished by CGRP. These results show that the CGRP-induced cAMP/PKA activation suppresses activation of MAPK induced by TGFβ1, leading to decreased PAI-1 expression in HepG2 cells.     

Effect of amines as activators on the alcohol-oxidizing activity of pyrroloquinoline quinone-dependent quinoprotein alcohol dehydrogenase

Pyrroloquinoline quinone-dependent quinoprotein alcohol dehydrogenases (PQQ-ADH) require ammonia or primary amines as activators in in vitro assays with artificial electron acceptors. We found that PQQ-ADH from Pseudomonas putida KT2440 (PpADH) was activated by various primary amines, di-methylamine, and tri-methylamine. The alcohol oxidation activity of PpADH was strongly enhanced and the affinity for substrates was also improved by pentylamine as an activator.     

3-Substituted-4-hydroxycoumarin as a new scaffold with potent CDK inhibition and promising anticancer effect: Synthesis,molecular modeling and QSAR studies

A new series of 3-substituted-4-hydroxycoumarin derivatives was designed, synthesized, and evaluated for CDK inhibiting and anticancer activities. All the synthesized target compounds showed remarkably high affinity and selectivity towards CDK1B, compared to flavopiridol, with Ki values in the low nanomolar range (Ki = 0.35–0.88 nM). Most of them elicited considerable inhibiting effect against CDK9T1 (Ki = 3.26–23.45 nM). Moreover, all the target compounds were tested in vitro against eighteen types of human tumor cell lines. The hydrazone 3a, N-phenylpyrazoline derivative 6b and 2-aminopyridyl-3-carbonitrile derivative 8c were the most potent anticancer agents against MCF-7 breast cancer cell line (IC₅₀ = 0.21, 0.21 and 0.23 nM, respectively). The target compounds 3a, 6b and 8c were further evaluated in MCF-7 breast cancer mouse xenograft model and showed in vivo efficacy at 10 mg/kg dose. The docking study confirmed a unique binding mode in the active site of CDK1B with better score than flavopiridol. Quantitative structure activity relationship study was done and revealed a highly predictive power R² of 0.81.     

Urokinase links plasminogen activation and cell adhesion by cleavage of the RGD motif in vitronectin

Components of the plasminogen activation system including urokinase (uPA), its inhibitor (PAI‐1) and its cell surface receptor (uPAR) have been implicated in a wide variety of biological processes related to tissue homoeostasis. Firstly, the binding of uPA to uPAR favours extracellular proteolysis by enhancing cell surface plasminogen activation. Secondly, it promotes cell adhesion and signalling through binding of the provisional matrix protein vitronectin. We now report that uPA and plasmin induces a potent negative feedback on cell adhesion through specific cleavage of the RGD motif in vitronectin. Cleavage of vitronectin by uPA displays a remarkable receptor dependence and requires concomitant binding of both uPA and vitronectin to uPAR. Moreover, we show that PAI‐1 counteracts the negative feedback and behaves as a proteolysis‐triggered stabilizer of uPAR‐mediated cell adhesion to vitronectin. These findings identify a novel and highly specific function for the plasminogen activation system in the regulation of cell adhesion to vitronectin. The cleavage of vitronectin by uPA and plasmin results in the release of N‐terminal vitronectin fragments that can be detected in vivo, underscoring the potential physiological relevance of the process.     

Energy transfer between Ce3+ → Gd3+ or Tb3+ in KNaSO4 microphosphor

KNaSO₄ microphosphor doped with Ce,Gd and Ce,Tb and prepared by a wet chemical method was studied using X‐ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) characterization. KNaSO₄ has a 5‐µm particle size detected by SEM. KNaSO₄:Ce³⁺,Tb³⁺ showed blue and green emission (at 494 nm, 557 nm, 590 nm) of Tb³⁺ due to ⁵D₄ → ⁷F_J (J = 4, 5, 6) transitions. KNaSO₄:Ce³⁺,Gd³⁺ showed luminescence in the ultraviolet (UV) light region at 314 nm for an excitation at 271 nm wavelength. It was observed that efficient energy transfer took place from Ce³⁺ → Gd³⁺ and Ce³⁺ → Tb³⁺ sublattices indicating that Ce³⁺ could effectively sensitize Gd³⁺ or Tb³⁺ (green emission). Ce³⁺ emission weakened and Gd³⁺ or Tb³⁺ enhanced the emission significantly in KNaSO₄. This paper discusses the development and understanding of photoluminescence and the effect of Tb³⁺ and Gd³⁺ on KNaSO₄:Ce³⁺. Copyright © 2015 John Wiley & Sons, Ltd.     

原发性及狼疮性肾病综合征患者血清PAI-1、Lp(a)水平变化及其临床价值探讨

目的:探讨原发性及狼疮性肾病综合征患者纤溶酶原激活物抑制因子1(PAI-1)和血清脂蛋白a[Lp(a)]的水平变化及其检测的临床应用价值。方法:选取病理类型明确,临床初诊为肾病综合征的患者138例。其中原发性肾病综合征70例,为PNS组;系统性红斑狼疮继发性肾病综合征患者68例,为LNS组。同期选取本院健康体检正常者64例,为正常对照NC组。全自动生化分析仪检测各组血清Lp(a)和血脂等指标;酶联免疫吸附(Elisa)法测定血清PAI-1水平。结果:1与NC组比较,血清Lp(a)和PAI-1水平在PNS和LNS两组中均显著升高(P0.05),PNS组比LNS组升高更为明显,差异有统计学意义(P0.05);2LP(a)与PAI-1秩相关系数(rs)分析,在PNS组中r_s=0.328,P=0.006,LNS组中r_s=0.439,P=0.006;3二元logistic回归分析表明,LP(a)和PAI-1均是PNS和LNS的危险因素;4ROC曲线分析表明,血清Lp(a)、PAI-1对PNS和LNS诊断的ROC曲线下面积(AUC~(ROC))分别为0.895、0.874和0.848、0.813,两者联合检测对PNS和LNS诊断的AUC~(ROC)分别为0.947和0.919。结论:血清Lp(a)与PAI-1水平在PNS和LNS患者体内均明显升高,PNS患者升高更为显著;Lp(a)与PAI-1水平在PNS和LNS患者中均显著正相关;LP(a)和PAI-1均是PNS和LNS的危险因素,两者水平的变化与PNS和LNS的发生相关。联合检测Lp(a)与PAI-1水平对PNS和LNS的诊治具有一定的临床应用价值。