Engineering a "three-in-one" hirudin prodrug to reduce bleeding risk: A proof-of-concept study.

An ideal anticoagulant should have at least three properties including targeted delivery to the thrombosis site, local activation or releasing to centralize the anti-thrombosis effects and thus reduce the bleeding risks, and long persistence in circulation to avoid repeated administration. In the present study, we sought to test a "three-in-one" strategy to design new protein anticoagulants. Based on these criteria, we constructed two hirudin prodrugs, R824-HV-ABD and ABD-HV-R824. The R824 peptide can bind phosphatidylserine on the surface of the procoagulant platelets and thus guide the prodrug to the thrombosis sites; albumin-binding domain (ABDs) can bind the prodrug to albumin, and thereby increase its persistence in circulation; the hirudin (HV) core in the prodrug is flanked by factor Xa recognition sites, thus factor Xa at the thrombosis site can cleave the fusion proteins and release the activated hirudin locally. Hirudin prodrugs were able to bind with procoagulant platelets and human serum albumin in vitro with high affinity, targeted concentrated and prevented the formation of occlusive thrombi in rat carotid artery injury model. Their effective time was significantly extended compared to native hirudin, and R824-HV-ABD showed a significantly improved half-life of about 24 h in rats. The bleeding time of prodrug-treated mice was much shorter than that of hirudin-treated mice. The results from the proof-of-concept studies, for the first time, demonstrate that "three-in-one" prodrug strategy may be a good solution for protein or peptide anticoagulants to reduce their bleeding risks.

Improving long circulation and procoagulant platelet targeting by engineering of hirudin prodrug.

To reduce systemic bleeding risks during anticoagulant treatment, a new concept named "precise anticoagulation" was proposed to localize the effects of anticoagulants via the targeted delivery of prodrugs to the coagulation site. In this study, the fusion protein Annexin V-hirudin 3-ABD (hAvHA) was constructed to achieve the prolonged circulation and targeted delivery of hirudin to coagulation sites. hAvHA was inactive as a prodrug, and it could bind to albumin during circulation. The drug was quickly activated via factor Xa-mediated cleavage once coagulation occurred, and hirudin was efficiently released to exert antithrombin activity in vitro. The hAvHA protein could be activated in mouse blood and exert significant anticoagulation effects. The results of FITC labeling illustrated that hAvHA bound to procoagulant platelets, suggesting the Annexin V modification permits targeted delivery to sites of thrombosis. hAvHA bound to albumin in vitro with an equilibrium dissociation constant of 8 pM, suggesting the ABD modification permitted prolonged circulation in vivo. Moreover, the bleeding time was much shorter in hAvHA-treated mice than in hirudin-treated mice. Therefore, our results suggested that that hAvHA is a potential and promising anticoagulant in vivo.

Improvement and Application of Acute Blood Stasis Rat Model Aligned with the 3Rs (Reduction, Refinement and Replacement) of Humane Animal Experimentation.

OBJECTIVE: To establish a novel cardiocentesis method for withdrawing venous blood from the right atrium, and to improve an acute blood stasis rat model using an ice bath and epinephrine hydrochloride (Epi) while considering the 3Rs (reduction, refinement, and replacement) of humane animal experimentation. METHODS: An acute blood stasis model was established in male Sprague-Dawley rats by subcutaneous injection (s.c.) Epi (1.2 mg/kg) administration at 0 h, followed by a 5-min exposure to an ice-bath at 2 h and s.c. Epi administration at 4 h. Control rats received physiological saline. Rats were fasted overnight and treated with Angelicae Sinensis Lateralis Radix (ASLR) and Pheretima the following day. Venous blood was collected using our novel cardiocentesis method and used to test whole blood viscosity (WBV), prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen (FIB) content. RESULTS: The rats survived the novel cardiocentesis technique; WBV value returned to normal while hematological parameters such as hemoglobin level and red blood cell count were restored to >94% of the corresponding values in normal rats following a 14-day recovery. Epi (1.2 mg/kg, s.c.) combined with a 5-min exposure to the ice bath replicated the acute blood stasis rat model and was associated with the highest WBV value. In rats showing acute blood stasis, ASLR treatment [4 g/(kg·d) for 8 days] decreased WBV by 9.98%, 11.09%, 9.34%, 9.00%, 7.66%, and 7.03% (P<0.05), while Pheretima treatment [2.6 g/(kg·d), for 8 days] decreased WBV by 25.49%, 25.94%, 16.28%, 17.76%, 11.07%, and 7.89% (P<0.01) at shear rates of 1, 3, 10, 30, 100, and 180 s-1, respectively. Furthermore, Pheretima treatment increased APTT significantly (P<0.01). CONCLUSIONS: We presented a stable, reproducible, and improved acute blood stasis rat model, which could be applied to screen drugs for promoting blood circulation and eliminating blood stasis.

Design and evaluation of EphrinA1 mutants with cerebral protective effect.

The activation of EphA2 receptor by its natural ligand EphrinA1 causes blood brain barrier dysfunction, and inactivation of EphA2 reduces BBB damage in ischemic stroke. Thus, EphA2 targeted antagonists may serve as neuroprotective agents. We engineered four mutants of EphrinA1, EM1, EM2, EM3 and EM4, respectively. The computational analysis showed that these four mutants were capable of interacting with EphA2. Their potential neuroprotective effects were examined in mouse focal ischemia/reperfusion (I/R) model. EM2 exhibited strong neuroprotective effects, including reduced brain infarct volume, neuronal apoptosis, cerebral edema, and improved neurological scores. The EM2-mediated protection was associated with a comparative decrease in BBB leakage, inflammatory infiltration, and higher expression levels of tight junction proteins, such as zonula occludens-1 and Occludin. I/R-induced high expression of Rho-associated protein kinase 2 (ROCK2) was down-regulated after EM2 treatment. Moreover, EM2 reduced agonist doxazosin-induced EphA2 phosphorylation and cells rounding in PC3 cells, indicating EphA2-antagonizing activity of EM2. These finding provided evidences of the neuroprotection of EphA2 antagonist and a novel approach for ischemic stroke treatment. These results also suggested that a receptor agonist can be switched to an antagonist by substituting one or more relevant residues.

Effect of magnolol on cerebral injury and blood brain barrier dysfunction induced by ischemia-reperfusion in vivo and in vitro.

Magnolol, a neolignan compound isolated from traditional Chinese medicine Magnolia officinalis, has a potentially therapeutic influence on ischemic stroke. Previous studies have demonstrated that cerebral ischemia-reperfusion (I-R) and blood-brain barrier (BBB) are involved in the pathogeneses of stroke. Therefore, in vivo and in vitro studies were designed to investigate the effects of magnolol on I-R-induced neural injury and BBB dysfunction. In cerebral I-R model of mice, cerebral infarct volumes, brain water content, and the exudation of Evans blue were significantly reduced by intravenous injection with magnolol at the doses of 1.4, 7.0, and 35.0 µg/kg. When primary cultured microglial cells were treated with 1 µg/ml lipopolysaccharide (LPS) plus increasing concentrations of magnolol, ranging from 0.01 to 10 µmol/L, magnolol could statistically inhibit LPS-induced NO release, TNF-α secretion, and expression of p65 subunit of NF-κB in the nucleus of microglial cells. In the media of brain microvascular endothelial cells (BMECs), oxygen and glucose deprivation-reperfusion (OGD-R) could remarkably lead to the elevation of TNF-α and IL-1ß levels, while magnolol evidently reversed these effects. In BBB model in vitro, magnolol dose- and time-dependently declined BBB hyperpermeability induced by oxygen and glucose deprivation (OGD), OGD-R, and ephrin-A1 treatment. More importantly, magnolol could obviously inhibit phosphorylation of EphA2 (p-EphA2) not only in ephrin-A1-treated BMECs but also in cerebral I-R model of mice. In contrast to p-EphA2, magnolol significantly increased ZO-1 and occludin levels in BMECs subjected to OGD. Taken together, magnolol can protect neural damage from cerebral ischemia- and OGD-reperfusion, which may be associated with suppressing cerebral inflammation and improving BBB function.

Increased autophagic degradation contributes to the neuroprotection of hydrogen sulfide against cerebral ischemia/reperfusion injury.

Hydrogen sulfide (H2S), an endogenous gaseous signal molecule, exhibits protective effect against ischemic injury. However, its underlying mechanism is not fully understood. We have recently reported that exogenous H2S decreases the accumulation of autophagic vacuoles in mouse brain with ischemia/reperfusion (I/R) injury. To further investigate whether this H2S-induced reduction of autophagic vacuoles is caused by the decreased autophagosome synthesis and/or the increased autophagic degradation inautophagic flux, we performed in vitro and in vivo studies using SH-SY5Y cells for the oxygen and glucose deprivation/reoxygenation (OGD/R) and mice for the cerebral I/R, respectively. NaHS (a donor of H2S) treatment significantly increased cell viability and reduced cerebral infarct volume. NaHS treatment reduced the OGD/R-induced elevation in LC3-II (an autophagic marker), which was completely reversed by co-treatment with an autophagic flux inhibitor bafilomycin A1 (BafA1). However, H2S did not affect the OGD/R-induced increase of the ULK1 self-association and decrease of the ATG13 phosphorylation, which are the critical steps for the initiation of autophagosome formation. Cerebral I/R injury caused an increase in LC3-II, a decrease in p62 and the accumulation of autophagosomes in the cortex and the hippocampus, which were inhibited by NaHS treatment. This H2S-induced decline of LC3-II in ischemic brain was reversed by BafA1. Moreover, BafA1 treatment abolished the protection of H2S on the cerebral infarction. Collectively, the neuroprotection of exogenous H2S against ischemia/hypoxia and reperfusion/reoxygenation injury is mediated by the enhancement of autophagic degradation.

Identification of AcAP5 as a novel factor Xa inhibitor with both direct and allosteric inhibition.

Ancylostoma caninum anticoagulant peptide 5 (AcAP5) is a potent inhibitor for coagulation factor Xa (FXa). Previous studies show that AcAP5 binds to FXa at the active site, and/or the exosite. The active site-binding contributes to direct blocking of FXa catalytic activity, but the effect of exosite-binding and the underlying mechanism remain unknown. To investigate whether and how the exosite-binding affects FXa function, we prepared several AcAP5 mutants with modifications to the active site-binding or exosite-binding region. Their FXa-inhibiting and anticoagulant activities were examined both in vitro and in rabbit plasma, and the interactions with FXa were analyzed using in silico molecular modeling, docking, and molecular dynamics simulation. Mutants abolishing either active site- or exosite-binding resulted in a dramatic decrease in their anti-FXa and anticoagulant activities. Elongation of AcAP5 exosite-binding region also impaired the FXa-inhibiting activity. Computational analysis demonstrated that the conformation of FXa becomes more rigid due to exosite-binding with AcAP5, which consequently affects its catalytic activity. Our results suggest that both active site- and exosite-binding contribute to the FXa inhibitory activity of AcAP5.

Exogenous hydrogen sulfide attenuates cerebral ischemia-reperfusion injury by inhibiting autophagy in mice.

Hydrogen sulfide (H2S), the third gas transmitter, has been proven to be neuroprotective in cerebral ischemic injury, but whether its effect is mediated by regulating autophagy is not yet clear. The present study was undertaken to explore the underlying mechanisms of exogenous H2S on autophagy regulation in cerebral ischemia. The effects and its connection with autophagy of NaHS, a H2S donor, were observed through neurological deficits and cerebral infarct volume in middle cerebral artery occlusion (MCAO) mice; autophagy-related proteins and autophagy complex levels in the ischemic hemisphere were detected with Western blot assay. Compared with the model group, NaHS significantly decreased infarct volume and improved neurological deficits; rapamycin, an autophagy activator, abolished the effect of NaHS; NaHS decreased the expression of LC3-II and up-regulated p62 expression in the ischemic cortex 24 h after ischemia. However, NaHS did not significantly influence Beclin-1 expression. H2S has a neuroprotective effect on ischemic injury in MCAO mice; this effect is associated with its influence in down-regulating autophagosome accumulation.

Engineering Factor Xa Inhibitor with Multiple Platelet-Binding Sites Facilitates its Platelet Targeting.

Targeted delivery of antithrombotic drugs centralizes the effects in the thrombosis site and reduces the hemorrhage side effects in uninjured vessels. We have recently reported that the platelet-targeting factor Xa (FXa) inhibitors, constructed by engineering one Arg-Gly-Asp (RGD) motif into Ancylostoma caninum anticoagulant peptide 5 (AcAP5), can reduce the risk of systemic bleeding than non-targeted AcAP5 in mouse arterial injury model. Increasing the number of platelet-binding sites of FXa inhibitors may facilitate their adhesion to activated platelets, and further lower the bleeding risks. For this purpose, we introduced three RGD motifs into AcAP5 to generate a variant NR4 containing three platelet-binding sites. NR4 reserved its inherent anti-FXa activity. Protein-protein docking showed that all three RGD motifs were capable of binding to platelet receptor αIIbß3. Molecular dynamics simulation demonstrated that NR4 has more opportunities to interact with αIIbß3 than single-RGD-containing NR3. Flow cytometry analysis and rat arterial thrombosis model further confirmed that NR4 possesses enhanced platelet targeting activity. Moreover, NR4-treated mice showed a trend toward less tail bleeding time than NR3-treated mice in carotid artery endothelium injury model. Therefore, our data suggest that engineering multiple binding sites in one recombinant protein is a useful tool to improve its platelet-targeting efficiency.

Design, synthesis and biological evaluation of pyridazino[3,4,5-de]quinazolin-3(2H)-one as a new class of PARP-1 inhibitors.

A series of pyridazino[3,4,5-de]quinazolin-3(2H)-one derivatives were designed and synthesized as PARP-1 inhibitors. Most of the synthesized compounds showed good inhibitory activities of PARP-1 and four of them achieved at the IC50 values ranging from 0.0914 µM to 0.244 µM. Two compounds, 1a and 1b, were further tested for their neuroprotective effect in the PC12 cell model injured by H2O2 and both of them exhibited excellent activities.

Structure-guided creation of AcAP5-derived and platelet targeted factor Xa inhibitors.

Anticoagulants and anti-platelet agents are simultaneously administrated in clinical practice (i.e. percutaneous coronary intervention), which cause significant risk of systemic bleeding. Targeted delivery of anticoagulants to the activated platelets at sites of vascular injuries may condense the site-specific anticoagulant effect and reduce the hemorrhage side effects in uninjured vessels. To this end, we prepared three ancylostoma caninum anticoagulant peptide 5 (AcAP5) variants NR1, NR2 and NR3 engineered with a platelet-binding Arg-Gly-Asp (RGD) motif and evaluated their anti-Factor Xa (FXa) and platelet-binding effects. These RGD-containing AcAP5 variants were capable of interacting with platelet receptor αIIbß3 as shown in computational analysis. All variants, especially NR2 and NR3, retained entirely the anti-FXa function of parent AcAP5. Moreover, they prevented the formation of occlusive thrombi in rat carotid artery injury model, suggesting that they inhibit platelet aggregation in vivo. Further functional investigation of NR3 demonstrated that NR3 inhibited platelet aggregation in vitro and FXa activity in vivo, and prolonged the coagulation time, all in a dose-dependent manner. Through flow cytometry assay, we confirmed the binding of NR3 to αIIbß3 receptor. In mouse model of carotid artery endothelium injury, NR3-treated mice showed less tail bleeding time than AcAP5-treated mice, and aspirin plus NR3 treatment exhibited moderate reduction of blood loss compared with aspirin plus AcAP5 treatment. These results indicate the feasibility to engineer a novel FXa inhibitor specifically targeting the activated platelets, which centralizes its anticoagulation efficacy in the injured vascular endothelium and reduces the risk of systemic bleeding.

Magnolol derivative 002C-3 protects brain against ischemia-reperfusion injury via inhibiting apoptosis and autophagy.

Neuroprotective agents can rescue ischemic penumbra in cerebral ischemia. However, the clinically effective neuroprotective agents for cerebral ischemic injury remain deficient in clinic so far. This study was undertaken to investigate the brain protective effect of 002C-3 and its potential mechanisms in rats, and its preliminary toxicity in mice. A transient middle cerebral artery occlusion (tMCAO) model in rats was used to evaluate its effect and mechanism, a dose limited experiment was used to evaluate its preliminary toxicity. 10-50µg/kg of 002C-3 (single iv bolus after reperfusion) significantly reduced neurological scores, infarct volumes and brain water contents, and the effect was more potent than that of magnolol under the same mole dose; 50µg/kg of 002C-3 significantly decreased the number of TUNEL-positive cells, reduced the activity of caspase-3, and lowered the autophagy-related proteins LC3-II and Beclin-1 level in I-R cerebral tissue. At 1000 times' dose of high effective dose (ip) 002C-3 failed to show evident toxicity in mice, and the mean body weight of mice treated with 002C-3 was almost the same as that of the vehicle control, but magnolol caused evident toxicity and death. In conclusion, 002C-3 has significant protective effect against cerebral ischemia-reperfusion injury; the effect is more potent than magnolol; this effect is maybe associated with its inhibition of both apoptosis and autophagy; its toxicity is greatly reduced compared to magnolol. These results provided data for its further research and development.

Design, synthesis, and structure-activity and structure-pharmacokinetic relationship studies of novel [6,6,5] tricyclic fused oxazolidinones leading to the discovery of a potent, selective, and orally bioavailable FXa inhibitor.

The blood coagulation enzyme factor Xa (FXa) is a particularly promising target for anticoagulant therapy, and identification of oral small-molecule inhibitors of FXa remains a research focus. On the basis of the X-ray crystal structure of FXa and its inhibitor rivaroxaban, we designed and synthesized a series of conformationally restricted mimics containing a novel [6,6,5] tricyclic fused oxazolidinone scaffold. Intensive structure-activity relationship (SAR) and structure-pharmacokinetic relationship (SPR) studies on this new series led to the discovery of compound 11a: a highly potent, selective, direct, and orally bioavailable FXa inhibitor with excellent in vivo antithrombotic efficacy and preferable pharmacokinetic profiles. Druggability evaluation of compound 11a was undertaken and elicited positive outcomes. All results indicate that compound 11a is a promising drug candidate for the prevention and treatment of thromboembolic diseases in venous and arterial systems.

w007B protects brain against ischemia-reperfusion injury in rats through inhibiting inflammation, apoptosis and autophagy.

This study was designed to investigate the effect of w007B, a newly synthesized derivative of honokiol, on MCAO reperfusion, and its therapeutic time window and related mechanisms in rats. Neurological deficit scores, infarct size and brain water content were measured after 24 h reperfusion following 2 h ischemia. The results showed that w007B (10 and 50 µg/kg, IV immediately after reperfusion) markedly decreased neurological deficit scores, reduced infarct size and alleviated brain water content, and then 50 µg/kg w007B given within 3 h after reperfusion (5 h after ischemia) significantly attenuated ischemia-induced brain injury. Additionally, no sign of toxicity was observed when a single dose of 50mg/kg w007B (1000 times of the highest effective dose, IP) was administered. To explore the underlying mechanisms, the expression level of apoptosis, inflammation and autophagy-related markers in brain tissue were detected with kits or by western blot. It was observed that w007B rapidly and significantly reduced caspase-3 activity and NO production in the injured semi-brain, and also lowered the level of the p65 subunit of NF-κB in the nucleus. Besides, it also reduced the expression of Beclin-1 and LC3B-II, and increased the level of p62, the autophagy-related proteins in I/R-injured hemisphere. In conclusion, w007B exerts neuroprotective effect on cerebral ischemia-reperfusion injury with wider therapeutic time window and better safety; its mechanisms may be associated with its anti-inflammation, anti-apoptosis and anti-autophagy action. These results suggest that w007B shows strong potential as a clinical neuroprotective candidate for the treatment of ischemic stroke.

Neuroprotective effect of TAT-14-3-3ε fusion protein against cerebral ischemia/reperfusion injury in rats.

Stroke is the major cause of death and disability worldwide, and the thrombolytic therapy currently available was unsatisfactory. 14-3-3ε is a well characterized member of 14-3-3 family, and has been reported to protect neurons against apoptosis in cerebral ischemia. However, it cannot transverse blood brain barrier (BBB) due to its large size. A protein transduction domain (PTD) of HIV TAT protein, is capable of delivering a large variety of proteins into the brain. In this study, we generated a fusion protein TAT-14-3-3ε, and evaluated its potential neuroprotective effect in rat focal ischemia/reperfusion (I/R) model. Western blot analysis validated the efficient transduction of TAT-14-3-3ε fusion protein into brain via a route of intravenous injection. TAT-14-3-3ε pre-treatment 2 h before ischemia significantly reduced cerebral infarction volume and improved neurologic score, while post-treatment 2 h after ischemia was less effective. Importantly, pre- or post-ischemic treatment with TAT-14-3-3ε significantly increased the number of surviving neurons as determined by Nissl staining, and attenuated I/R-induced neuronal apoptosis as showed by the decrease in apoptotic cell numbers and the inhibition of caspase-3 activity. Moreover, the introduction of 14-3-3ε into brain by TAT-mediated delivering reduced the formation of autophagosome, attenuated LC3B-II upregulation and reversed p62 downregulation induced by ischemic injury. Such inhibition of autophagy was reversed by treatment with an autophagy inducer rapamycin (RAP), which also attenuated the neuroprotective effect of TAT-14-3-3ε. Conversely, autophagy inhibitor 3-methyladenine (3-MA) inhibited I/R-induced the increase in autophagic activity, and attenuated I/R-induced brain infarct. These results suggest that TAT-14-3-3ε can be efficiently transduced into brain and exert significantly protective effect against brain ischemic injury through inhibiting neuronal apoptosis and autophagic activation.

Engineering novel anticoagulant proteins by motif grafting.

Structure-based rational design has been considered as a promising approach to design novel proteins. For this purpose, we designed artificial anticoagulant proteins that are able to target Factor Xa (FXa) using a functional motifgrafting approach. The motif corresponded to the residues Cys15 to Cys42 of Ancylostoma caninum anticoagulant peptide 5 (AcAP5), a potent FXa inhibitor. By screening of the Protein Data Bank (PDB) using Vector Alignment Search Tool (VAST, search for three-dimensional scaffolds in protein structures), we screened scaffolds as hosts to reproduce the functional topology of this motif. Three designed artificial chimeric proteins were expressed and purified to test their FXainhibiting ability. One of the recombinant proteins, pep3, was found to inhibit FXa with strong activity (IC50 of 152 nM) in vitro. Moreover, pep3 inhibited arterial thrombosis formation in rats with uniform potency compared with natural AcAP5. Therefore, our data demonstrate that motif-grafting is a useful tool to engineer novel artificial anticoagulant proteins.

Honokiol inhibits the inflammatory reaction during cerebral ischemia reperfusion by suppressing NF-κB activation and cytokine production of glial cells.

This study was designed to investigate the effects of honokiol, a neuroprotective agent, on cerebral edema in cerebral ischemia reperfusion (IR) mice and its mechanism of anti-inflammation. Honokiol (0.7-70µg/kg) significantly reduced brain water contents and decreased the exudation of Evans blue dye from brain capillaries in cerebral IR mice. Honokiol (0.1-10µM) significantly reduced the p65 subunit level of NF-κB in the nucleus of primary culture-microglia. It (0.01-10µM) evidently reduced nitric oxide (NO) level in the microglia culture medium and in the microglia and astrocytes coculture medium. Honokiol (0.01-10µM) significantly decreased the level of TNF-α in the microglia medium or coculture cell medium. Honokiol (10µM) decreased the level of Regulated upon Activation Normal T-cell Expressed and Secreted (RANTES/CCL5) protein in medium of microglia or astrocytes. In conclusion, Honokiol has a potent anti-inflammatory effect in cerebral ischemia-reperfusion mice and this effect might be attributed to its inhibition ability on the NF-κB activation, consequently blocking the production of inflammatory factors including: NO, tumor necrosis factor-α (TNF-α) and RANTES/CCL5 in glial cells. These results provide evidence for the anti-inflammatory effect of honokiol for the potential treatment of ischemic stroke.

Honokiol protects brain against ischemia-reperfusion injury in rats through disrupting PSD95-nNOS interaction.

Honokiol, a major bioactive constituent of the bark of Magnolia officinalis has been confirmed to have the neuroprotective effect on ischemic stroke in rats. This study was designed to observe the therapeutic time window of honokiol microemulsion on cerebral ischemia-reperfusion injury to support its potential for future clinical trials and further explore the underlying mechanisms. Honokiol microemulsion (50µg/kg, i.v. at 0, 1 or 3h after reperfusion) significantly reduced neurological deficit, infarct volume and brain water content in rats subjected to cerebral ischemia-reperfusion, and honokiol (0.1-10µM) significantly attenuated oxygen-glucose deprivation- or glutamate-induced injury of fetal rat cortical neurons. In co-immunoprecipitation and western blot test, honokiol decreased the intensity of nNOS related to PSD95 but failed to affect that of PSD95 related to NR2B in NR2B-PSD95-nNOS complex, and it also inhibited the translocation of nNOS from cytosol to membrane without affecting total nNOS expression, and then markedly decreased NO production in cortical neurons. Besides, the results of whole-cell patch-clamp recordings showed that honokiol reversibly inhibited the NMDA current by about 64%. In conclusion, honokiol has a therapeutic window of at least 5h after the onset of cerebral ischemia or 3h after reperfusion in rats, which may be in part ascribed to the disruption of the PSD95-nNOS interaction leading to the inhibition of neurotoxic NO production.

Synthesis, nanofeatures, in vitro thrombus lysis activity and in vivo thrombolytic activity of poly-alpha,beta-aspartyl-L-alanine.

AIM: Applying nanoscale assembly to the design of a thrombolytic agent. MATERIALS: poly-alpha,beta-DL-aspartyl-L-alanine (molecular weight: 15726 atomic mass units) from the thermal polycondensation of DL-aspartic acid and the amidation of polysuccimide with L-alanine. METHODS: The correlation of concentration and pH with nanofeatures, the correlation of concentration with in vitro thrombus lysis activity, the correlation of dose with the in vivo thrombolytic activity and the correlation of the dose with nanofeatures are all explained in this article. RESULTS: Poly-alpha,beta-DL-aspartyl-L-alanine was concentration- (6.4 x 10(4,2,-4,-6,-8,-10,-12) nM) and pH-dependently (pH 1.2, 7.4 and 7.6) assembled to various nanospecies, exhibited concentration-dependent (4, 8 and 16 microM) lysis action in vitro and dose-dependent (5, 0.5 and 0.05 micromol/kg) thrombolytic action in vivo. CONCLUSION: Upon entering the stomach, intestinal tract, blood and tissue fluids, poly-alpha,beta-DL-aspartyl-L-alanine assembled to small nanoparticles or nanoblocks to escape the entrapment by macrophages and exhibited desirable thrombolytic action.

[Constituents of Millettia nitida var. hirsutissima].

OBJECTIVE: To separate effective constituents from Millettia nitida var. hirsutissima. METHOD: Compounds were isolated by chromatography methods, structures were identified by spectroscopic means. RESULT: Eight flavonoids (1-8) and two triterpenes (9-10) were isolated from this plant. They were identified as calycosin (1), genistin (2), gliricidin (3), 8-O-methylretusin (4), afromosin-7-O-beta-D-glucopyranoside (5), lanceolarin (6), soliquiritigenin (7), symplocoside (8), lupeol (9), 3beta-friedelanol (10). CONCLUSION: The compounds (1-10) were obtained from M. nitida var. hirsutissima for the first time. The 13C-NMR dada of 1 were correct assignment on the basis of 2D-NMR spectral analysis.