Fenfei Gao

Self-assembled nanoparticles of glycyrrhetic acid-modified pullulan as a novel carrier of curcumin.

Glycyrrhetic acid (GA)-modified pullulan nanoparticles (GAP NPs) were synthesized as a novel carrier of curcumin (CUR) with a degree of substitution (DS) of GA moieties within the range of 1.2–6.2 groups per hundred glucose units. In the present study, we investigated the physicochemical characteristics, release behavior, in vitro cytotoxicity and cellular uptake of the particles. Self-assembled GAP NPs with spherical shapes could readily improve the water solubility and stability of CUR. The CUR release was sustained and pH-dependent. The cellular uptake of CUR-GAP NPs was confirmed by green fluorescence in the cells. An MTT study showed CUR-GAP NPs with higher cytotoxicity in HepG2 cells than free CUR, but GAP NPs had no significant cytotoxicity. GAP is thus an excellent carrier for the solubilization, stabilization, and controlled delivery of CUR.

The Protective Effect of Egr-1 Antisense Oligodeoxyribonucleotide on Myocardial Injury Induced by Ischemia-reperfusion and Hypoxia- reoxygenation

Aims: Our previous studies have shown that myocardial ischemia-reperfusion (I/R) injury is related closely with early growth response (Egr)-1 overexpression. The present study is to confirm thoroughly the effects of Egr-1 on the occurrance and development of myocardial I/R injury. Methods: The Sprague-Dawley rat myocardial I/R model and cultured cardiomyocyte hypoxia-reoxygenation (H/R) model were established. The synthesized Egr-1 antisense oligodeoxyribonucleotide (AS-ODN) was transfected into myocardial tissues and cells. Hemodynamic parameters, myeloperoxidase (MPO), cardiac troponin I (cTnI), tumor necrosis factor-α (TNF-α), morphology, spontaneous beat and cell viability were measured to assess the degree of injury and inflammation of myocardial tissues and cells. Results: In vivo, Egr-1 AS-ODN significantly attenuated injury and inflammation of myocardial tissues caused by I/R evidenced by the amelioration of hemodynamics and the reduction in MPO activity. In vitro, Egr-1 AS-ODN significantly relieved injury and inflammation of cultured cardiomyocyte caused by H/R evidenced by the improvement in morphology, structure and beat as well as the decrease in leakage of cTnI and release of TNF-α from cultured cardiomyocyte. Conclusions: These data suggest that Egr-1 plays a vital role in the pathogenesis of myocardial I/R injury and Egr-1 AS-ODN could protect the myocardium from I/R injury.

Effect of N -n-butyl haloperidol iodide on ROS/JNK/Egr-1 signaling in H9c2 cells after hypoxia/reoxygenation

Reactive oxygen species (ROS)-induced oxidative stress in cells is an important pathophysiological process during myocardial ischemia/reperfusion (I/R) injury, and the transcription factor Egr-1 is a master switch for various damage pathways during reperfusion injury. An in vitro model of myocardial I/R injury and H9c2 cardiomyoblast cells hypoxia/reoxygenation (H/R) was used to assess whether there is abnormal intracellular ROS/JNK/Egr-1 signaling. We also assessed whether N-n-butyl haloperidol (F2), which exerts protective effects during myocardial I/R injury, can modulate this pathway. H/R induced ROS generation, JNK activation, and increased the expression of Egr-1 protein in H9c2 cells. The ROS scavengers edaravone (EDA) and N-acetyl-L-cysteine (NAC) reduced ROS level, downregulated JNK activation, and Egr-1 expression in H9c2 cells after H/R. The JNK inhibitor SP600125 inhibited Egr-1 overexpression in H9c2 cells caused by H/R. F2 could downregulate H/R-induced ROS level, JNK activation, and Egr-1 expression in H9c2 cells in a dose-dependent manner. The ROS donor hypoxanthine-xanthine oxidase (XO/HX) and the JNK activator ANISO antagonized the effects of F2. Therefore, H/R activates ROS/Egr-1 signaling pathway in H9c2 cells, and JNK activation plays an important role in this pathway. F2 regulates H/R-induced ROS/JNK/Egr-1 signaling, which might be an important mechanism by which it antagonizes myocardial I/R injury.

Effect of Pullulan Nanoparticle Surface Charges on HSA Complexation and Drug Release Behavior of HSA-Bound Nanoparticles

Nanoparticle (NP) compositions such as hydrophobicity and surface charge are vital to determine the presence and amount of human serum albumin (HSA) binding. The HSA binding influences drug release, biocompatibility, biodistribution, and intercellular trafficking of nanoparticles (NPs). Here, we prepared 2 kinds of nanomaterials to investigate HSA binding and evaluated drug release of HSA-bound NPs. Polysaccharides (pullulan) carboxyethylated to provide ionic derivatives were then conjugated to cholesterol groups to obtain cholesterol-modified carboxyethyl pullulan (CHCP). Cholesterol-modified pullulan (CHP) conjugate was synthesized with a similar degree of substitution of cholesterol moiety to CHCP. CHCP formed self-aggregated NPs in aqueous solution with a spherical structure and zeta potential of −19.9±0.23 mV, in contrast to −1.21±0.12 mV of CHP NPs. NPs could quench albumin fluorescence intensity with maximum emission intensity gradually decreasing up to a plateau at 9 to 12 h. Binding constants were 1.12×105 M−1 and 0.70×105 M−1 to CHP and CHCP, respectively, as determined by Stern-Volmer analysis. The complexation between HSA and NPs was a gradual process driven by hydrophobic force and inhibited by NP surface charge and shell-core structure. HSA conformation was altered by NPs with reduction of α-helical content, depending on interaction time and particle surface charges. These NPs could represent a sustained release carrier for mitoxantrone in vitro, and the bound HSA assisted in enhancing sustained drug release.

N -n-butyl haloperidol iodide protects cardiomyocytes against hypoxia/reoxygenation injury by inhibiting autophagy

N-n-butyl haloperidol iodide (F2), a novel compound derived from haloperidol, protects against the damaging effects of ischemia/reperfusion (I/R) injury in vitro and in vivo. In this study, we hypothesized the myocardial protection of F2 on cardiomyocyte hypoxia/reoxygenation (H/R) injury is mediated by inhibiting autophagy in H9c2 cells. The degree of autophagy by treatment with F2 exposed to H/R in H9c2 cell was characterized by monodansylcadaverine, transmission electron microscopy, and expression of autophagy marker protein LC3. Our results indicated that treatment with F2 inhibited autophagy in H9c2 cells exposed to H/R. 3-methyladenine, an inhibitor of autophagy, suppressed H/R-induced autophagy, and decreased apoptosis, whereas rapamycin, a classical autophagy sensitizer, increased autophagy and apoptosis. Mechanistically, macrophage migration inhibitory factor (MIF) was inhibited by F2 treatment after H/R. Accordingly, small interfering RNA (siRNA)-mediated MIF knockdown decreased H/R-induced autophagy. In summary, F2 protects cardiomyocytes during H/R injury through suppressing autophagy activation. Our results provide a new mechanistic insight into a functional role of F2 against H/R-induced cardiomyocyte injury and death.

N-4-tert-butyl benzyl haloperidol chloride suppresses Ca2+-dependent Egr-1 expression and subsequently inhibits vascular smooth muscle cell proliferation induced by angiotensin II.

Background: N-4-Tert-Butyl benzyl haloperidol chloride (C3) was a novel calcium antagonist synthesized in our laboratory. The present study is to explore the effect of C3 on vascular smooth muscle cell proliferation and the mechanism involved. Methods: The effects of C3 on Ang II-induced cytosolic free Ca2+ concentration change, VSMC proliferation, the key early growth response factor 1 (Egr-1) were evaluated by laser scanning confocal microscopy, microtiter tetrazolium (MTT) proliferation assay, flow cytometry analysis, Western blot and RT-PCR analysis, respectively. An extracellular Ca2+ chelator EGTA and antisense Egr-1 oligodeoxyribonucleotides (ODNs) were used to establish the relation between Ca2+-dependent Egr-1 expression induced by Ang II and VSMC proliferation. Results: C3 attenuated the Ang II-induced extracellular Ca2+ influx, inhibited VSMCs proliferation and arrested VSMCs in G1-phase. C3 also triggered a significant reduction in PDGF-A and cyclin D1, Cdk2 along with an overexpression of p21Cip1. Antisense Egr-1 ODNs inhibited VSMCs proliferation, which was related to G1-phase arrest, due to inhibiting the expression of Egr-1 and C3 inhibited the overexpression of Egr-1. Conclusion: Egr-1 may play a key role in Ang II-induced proliferation of VSMCs. C3 inhibits vascular smooth muscle cell proliferation and the mechanism is involved with the inhibition of over-expression of Egr-1.

N-n-butyl Haloperidol Iodide Protects Cardiac Microvascular Endothelial Cells From Hypoxia/Reoxygenation Injury by Down-Regulating Egr-1 Expression

Aims: Our previous studies have shown that N-n-butyl haloperidol iodide (F2) can antagonize myocardial ischemia/reperfusion (I/R) injury by down-regulating the early growth response (Egr)-1 expression, but the molecular mechanisms are not well understood. Because there is evidence implicating myocardial I/R injury is closely associated with endothelial dysfunction. The present study is to test the hypothesis that the protective effects of F2 on myocardial I/R injury is related closely with down-regulating Egr-1 expression on cardiac microvascular endothelial cells (CMECs). Methods: A model of cultured CMECs exposed to hypoxia/reoxygenation (H/R) was developed. With antisense Egr-1 oligodeoxyribonucleotide (ODN), the relationship between Egr-1 expression and endothelial H/R injury was investigated. Egr-1 mRNA and protein expression were examined by real-time fluorescent quantitative PCR, immunocytochemical staining and Western-blot analysis. Lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), intercellular adhesion molecule-1 (ICAM-1), adherence of neutrophil and platelets, and cell viability were measured after H/R to evaluate the degree of endothelial injury. Results: Pretreatment with antisense Egr-1 ODN significantly reduced Egr-1 protein expression and attenuated injury of CMECs. Consistent with down-regulation of Egr-1 expression by F2, inflammation and other damage were significantly reduced as evidenced by a decrease of ICAM-1 expression, reduction of neutrophil and platelets adherence, increase in SOD, and decreases in MDA and LDH levels, resulting in the rise of cell viability. Conclusions: We demonstrate a protective effect of F2 in CMECs against H/R injury by down-regulating Egr-1 expression, which might be play a vital role in the pathogenesis of myocardial I/R injury.

Cardiac Electrophysiological and Antiarrhythmic Effects of N-n-butyl Haloperidol Iodide

Aims: N-n-butyl haloperidol (F₂), a novel compound of quaternary ammonium salt derivatives of haloperidol, was reported to antagonize myocardial ischemia/reperfusion injuries. The antiarrhythmic potential and electrophysiological effects of F₂ on rat cardiac tissues were investigated. Methods and Results: In Langendorff-perfused rat hearts, the ventricular arrhythmias were induced by left anterior descending coronary artery of rat heart ligated for 20 min before the release of the ligature. F₂ provided some inhibitive effects against ischemia- and reperfusion-induced ventricular arrhythmias. In His bundle electrogram and epicardial ECG recordings, the drug produced bradycardia, delayed the conduction through the atrioventricular node and prolonged the Wenckebach cycle length and atrioventricular nodal effective refractory period. In whole-cell patch-clamp study, F₂ primarily inhibited the L-type Ca²⁺ current (I_Ca,L) (IC₅₀ = 0.17 µM) with tonic blocking properties and little use-dependence. And the drug also decreased the Na⁺ current (IC₅₀ = 77.5 µM), the transient outward K⁺ current (IC₅₀ = 20.4 µM), the steady-state outward K⁺ current (IC₅₀ = 56.2 µM) and the inward rectifier K⁺ current (IC₅₀ = 127.3 µM). Conclusion: F₂ may be a promising drug for the treatment of ischemic heart disease with cardiac arrhythmia.

N-n-butyl haloperidol iodide preserves cardiomyocyte calcium homeostasis during hypoxia/ischemia.

Aims: N-n-Butyl haloperidol iodide (F2) is a novel compound derived from haloperidol. In our previous work, F2 was found to be an L-type calcium channel blocker which played a protective role in rat heart ischemic–reperfusion injury in a dose-dependent manner. In the current study, we aimed to investigate the effects and some possible mechanisms of F2 on calcium transients in hypoxic/ischemic rat cardiac myocytes. Methods and Results: Calcium transients’ images of rat cardiac myocytes were recorded during simulated hypoxia, using a confocal calcium imaging system. The amplitude, rising time from 25% to 75% (RT25-75), decay time from 75% to 25% (DT75-25) of calcium transients, and resting [Ca2+]i were extracted from the images by self-coding programs. In this study, hypoxia produced a substantial increase in diastolic [Ca2+]i and reduced the amplitude of calcium transients. Both RT25-75 and DT75-25 of Ca2+ transients were significantly prolonged. And F2 could reduce the increase in resting [Ca2+]iand the prolongation of RT25-75 and DT75-25 of Ca2+ transients during hypoxia. F2 also inhibited the reduction in amplitude of calcium transients which was caused by 30-min hypoxia. The activity of SERCA2a (sarcoplasmic reticulum Ca2+-ATPase, determined by test kits) decreased after 30-min ischemia, and intravenous F2 in rats could ameliorate the decreased activity of SERCA2a. The inward and outward currents of NCX (recorded by whole-cell patch-clamp analysis) were reduced during 10-min hypoxia, and F2 further inhibited the outward currents of NCX during 10-min hypoxia. All these data of SERCA2a and NCX might be responsible for the changes in calcium transients during hypoxia. Conclusion: Our data suggest that F2 reduced changes in calcium transients that caused by hypoxia/ischemia, which was regarded to be a protective role in calcium homeostasis of ventricular myocytes, probably via changing the function of SERCA2a.

Egr-1, a Central and Unifying Role in Cardioprotection from Ischemia-Reperfusion Injury?

Aims: Our previous studies have shown that N-n-butyl haloperidol iodide (F2) can antagonize myocardial ischemia/reperfusion (I/R) injury by blocking intracellular Ca2+ overload and suppressing Egr-1 overexpression. The present study is to investigate the relation between the reduction of Ca2+ overload and the inhibition of Egr-1 overexpression. Methods: The Sprague-Dawley rat myocardial I/R model and cultured cardiomyocyte hypoxia-reoxygenation (H/R) model were established. Administration of Egr-1 antisense oligodeoxyribonucleotide (AS-ODN) only or combining with F2, Egr-1 protein expression was examined by Western-blot analyses. Hemodynamic parameters, creatine kinase (CK) and lactate dehydrogenase (LDH), superoxide dismutase (SOD) and malondialdehyde (MDA), myeloperoxidase (MPO), cardiac troponin I (cTnI), and tumor necrosis factor-α (TNF-α) were measured to assess the degree of injury and inflammation of myocardial tissues and cells. Results: Treatment with Egr-1 AS-ODN significantly reduced Egr-1 protein expression and attenuated injury and inflammation of myocardium caused by I/R or H/R evidenced by the amelioration of hemodynamics, the decrease in leakage of CK, LDH, cTnI, the increase in MDA generation, the decrease in SOD activity, the reduction of MPO activity in myocardial tissues and release of TNF-α from cultured cardiomyocytes. Treatment with F2 combined with Egr-1 AS-ODN, the inhibition of Egr-1 protein expression and inflammation (MPO activity and TNF-α level) were not enhanced, but the protection from myocardial I/R (or H/R) injury was significantly increased in hemodynamics and cytomembrane permeability relative to the using of Egr-1 AS-ODN only. Conclusion: These data suggest that the inhibition of Egr-1 overexpression cannot involve all mechanisms of cardioprotection from I/R injury.