Angiotensin II receptor blocker attenuates PDGF-induced mesangial cell migration in a receptor-independent manner

Clinical studies have shown that angiotensin II (Ang II) type 1 (AT1) receptor blockers (ARBs) are able to provide renoprotection independent of their blood pressure lowering effects. ARBs also are reported to suppress oxidative stress, inflammation and certain other cellular responses in a receptor-independent manner. We investigated the effects of an ARB, olmesartan, on the cell migration induced by platelet-derived growth factor (PDGF), a major mitogen involved in the pathogenesis of glomerulonephritis in rat mesangial cells (RMCs). Cell migration was determined by a modified Boyden chamber assay. The intracellular signalling pathway was examined by western blotting. AT1 receptor expression was knocked down by small interfering RNAs. The intracellular reactive oxygen species (ROS) was measured by using a fluorescent probe. The O(2)(.-) scavenging activities were studied by the electron paramagnetic resonance-spin trapping method. PDGF-induced cell migration was inhibited by olmesartan in AT1 receptor knockdown RMCs. Olmesartan attenuated big mitogen-activated protein (MAP) kinase 1 (BMK1) and Src activation by PDGF in AT1 receptor knockdown RMCs. PDGF-induced BMK1 activation was suppressed by the Src family tyrosine kinase inhibitors, indicating that Src exists upstream of BMK1. The NADPH oxidase inhibitors inhibited not only PDGF-induced BMK1 and Src activation but also RMC migration. The elevation in ROS generation induced by PDGF was decreased by olmesartan. Olmesartan displayed neither directly ROS scavenging activity nor the inhibition of ROS-mediated intracellular signalling in RMCs. Olmesartan attenuates ROS generation by PDGF, leading to the subsequent inhibition of Src/ BMK1/migration in an AT1 receptor-independent manner in RMCs.


Role of Hypoxia-Inducible Factor 1α in T Cells as a Negative Regulator in Development of Vascular Remodeling

Recent studies have shown that the cellular immune response in the development of vascular remodeling modulates the resulting pathological alterations. We show that hypoxia-inducible factor 1 (Hif-1) (specifically expressed in T cells) is involved in the immune response to vascular remodeling that accompanies arteriosclerosis. To study the role of T cells in the development of vascular remodeling, femoral arterial injury induced by an external vascular polyethylene cuff was examined in mice lacking Hif-1 (specifically in T cells). We found that cuff placement caused prominent neointimal hyperplasia of the femoral artery in Hif-1- (T-cell)-deficient mice compared with that in control mice and that infiltration of inflammatory cells at the adventitia was markedly increased in the mutant mice. Studies to clarify the mechanism of augmented vascular remodeling in the mutant mice showed enhanced production of cytokines by activated T cells and augmented antibody production in response to a T-dependent antigen in the mutant mice. The results of this study revealed that Hif-1alpha in T cells plays a crucial role in vascular inflammation and remodeling in response to cuff injury as a negative regulator of T cell-mediated immune response. Potential new therapeutic strategies that target Hif-1alpha are described.

Arteriosclerosis, Thrombosis, and Vascular Biology


Inhibitory effects of adiponectin on platelet-derived growth factor-induced mesangial cell migration

Adiponectin, an adipocyte-derived hormone, has been involved in metabolic syndrome, a known risk factor for the development of chronic kidney disease (CKD). Recent studies have demonstrated that plasma adiponectin levels are elevated when kidney function declines in patients with CKD. Excessive mesangial cell (MC) turnover is one of the important features of CKD. The aim of the present study is to elucidate the effects of adiponectin on platelet-derived growth factor (PDGF)-induced cell migration and intracellular signaling pathways, in cultured rat MCs (RMCs). PDGF-induced RMC migration was significantly inhibited by the pretreatment of adiponectin. Adiponectin alone had no effect on RMC migration. Big mitogen-activated protein (MAP) kinase 1 (BMK1), p38 MAP kinase, and Akt were activated by PDGF stimulation in a time- and concentration-dependent manner in RMC. Adiponectin alone did not affect BMK1, p38 MAP kinase, and Akt phosphorylations in RMC. PDGF-induced BMK1 and p38 MAP kinase phosphorylations were significantly attenuated by the pretreatment of adiponectin in RMCs. On the other hand, the phosphorylation of Akt by PDGF was not diminished by the pretreatment of adiponectin. Adiponectin had no effects on PDGF-receptor autophosphorylation by PDGF. We also confirmed that PDGF-induced RMC migration was significantly suppressed by siBMK1 transfection or SB203580, a p38 MAP kinase inhibitor. From these findings, it is implied that the elevated plasma adiponectin levels in patients with CKD might play a compensatory role aimed at counteracting renal dysfunction related to MC disorders.


Adiponectin inhibits insulin-like growth factor-1-induced cell migration by the suppression of extracellular signal-regulated kinase 1/2 activation, but not Akt in vascular smooth muscle cells

Adiponectin, an adipocyte-derived hormone, has been proposed to show antiatherogenic properties through the inhibitory effects against various growth factors. Insulin-like growth factor-1 (IGF-1) is one of the potent mitogens, which has been considered to play important roles in both atherogenesis and plaque stabilization in accordance to the phase of atherosclerosis. The aim of this study is to elucidate the adiponectin effects on IGF-1-induced cell migration and its intracellular signaling pathways in vascular smooth muscle cells (VSMCs). In this study, we assessed cell migration and several kinase activities in cultured rat aortic smooth muscle cells (RASMCs). Adiponectin pretreatment suppressed IGF-1-induced cell migration and extracellular signal-regulated kinase (ERK)1/2 activation, which is one of the major mediators for IGF-1-induced cell migration. In RASMCs, adiponectin and 5-aminoimidazole-4-carboxamide riboside (AICAR), a 5'-AMP-activated protein kinase (AMPK) activator, stimulated AMPK activation. AMPK activation by AICAR inhibited IGF-1-induced ERK1/2 activation and cell migration in RASMCs. On the other hand, phosphorylation of Akt and Bad, proapoptotic molecules of the Bcl-2 family, which were increased by IGF-1 stimulation, was not diminished by the pretreatment with adiponectin. It was shown that adiponectin inhibited IGF-1-induced VSMC migration through suppression of ERK1/2 activation, which might be implicated in AMPK activation. Furthermore, adiponectin selectively inhibited ERK1/2 pathway, not Akt-Bad pathway, stimulated by IGF-1. From these findings, it was implied that adiponectin suppressed IGF-1-induced VSMC migration and its signaling selectivity.


Quercetin Glucuronide Inhibits Cell Migration and Proliferation by Platelet-Derived Growth Factor in Vascular Smooth Muscle Cells

Many epidemiologic studies have reported that dietary flavonoids provide protection against cardiovascular disease. Quercetin, a member of the bioflavonoids family, has been proposed to have anti-inflammatory, anti-atherogenic, and anti-hypertensive properties leading to the beneficial effects against cardiovascular diseases. Recent studies demonstrated that orally administered quercetin appeared in plasma as glucuronide-conjugated forms in rats and humans. Therefore, we examined the effect of chemically synthesized quercetin glucuronide on platelet-derived growth factor (PDGF)-induced cell migration and kinase activation in cultured rat aortic smooth muscle cells (RASMCs). PDGF-induced RASMC migration was inhibited by quercetin 3-O-beta-D-glucuronide (Q3GA). Q3GA also attenuated PDGF-induced cell proliferation in RASMCs. PDGF activated extracellular-signal regulated kinase (ERK) 1/2, c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein (MAP) kinase, and Akt in RASMCs. PDGF-induced JNK and Akt activations were suppressed by Q3GA, whereas ERK1/2 and p38 MAP kinase activations were not affected. We also confirmed that PDGF-induced JNK and Akt activations were inhibited by antioxidants, N-acetylcysteine and diphenyleneiodonium chloride, in RASMCs. These findings suggest Q3GA would be an active metabolite of quercetin in plasma and may possess preventing effects for cardiovascular diseases relevant to vascular smooth muscle cell disorders.


Toward drug discovery for overcoming CKD: Development of drugs on endothelial cell protection for overcoming CKD

Chronic kidney disease (CKD) is becoming a major public health problem worldwide. It is important to protect endothelial function in CKD treatment because injury of the endothelium is a critical event for the generation and progression of CKD. Recently, clinical studies showed that nifedipine, an antihypertensive drug, acts as a protective agent of endothelial cells (ECs). Nifedipine is reported to partially decompose to a nitrosonifedipine that has high reactivity against lipid-derived radicals in vitro. However, it is still unclear whether nitrosonifedipine is a biologically active agent against endothelial injury. We observed that nitrosonifedipine was converted to radical form by reaction with cultured ECs. The cumene hydroperoxide mediated cytotoxity was reduced by nitrosonifedipine in cultured human glomerular ECs (HGECs). Also nitrosonifedipine suppressed the expression of TNF-alpha-induced intercellular cell adhesion molecule-1 in HGECs. Chronic administration of N(omega)-nitro-L-arginine methyl ester (L-NAME) caused systemic arterial hypertension, endothelial injury, and renal dysfunction. In L-NAME-induced hypertensive rats, nitrosonifedipine treatment improved not only the acetylcholine-induced vasodilation of the aortic rings, but also renal dysfunction such as increasing the levels of serum creatinine and urinary protein excretion. Our preliminary data suggest that nitrosonifedipine is a new and useful drug for the treatment of CKD involving ameliorating effects on EC disorder.


Dietary doses of nitrite restore circulating nitric oxide level and improve renal injury in L-NAME-induced hypertensive rats

We have reported that pharmacological doses of oral nitrite increase circulating nitric oxide (NO) and exert hypotensive effects in Nomega-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats. In this study, we examined the effect of a chronic dietary dose of nitrite on the hypertension and renal damage induced by chronic L-NAME administration in rats. The animals were administered tap water containing L-NAME (1 g/l) or L-NAME + nitrite (low dose: 0.1 mg/l, medium dose: 1 mg/l, high dose: 10 mg/l) for 8 wk. We evaluated blood NO levels as hemoglobin-NO adducts (iron-nitrosyl-hemoglobin), using an electron paramagnetic resonance method. Chronic administration of L-NAME for 8 wk induced hypertension and renal injury and reduced the blood iron-nitrosyl-hemoglobin level (control 38.8 +/- 8.9 vs. L-NAME 6.0 +/- 3.1 arbitrary units). Coadministration of a low dose of nitrite with L-NAME did not change the reduced iron-nitrosyl-hemoglobin signal and did not improve the L-NAME-induced renal injury. The blood iron-nitrosyl-hemoglobin signals of the medium dose and high dose of nitrite were significantly higher than that of L-NAME alone. Chronic administration of a medium dose of nitrite attenuated L-NAME-induced renal histological changes and proteinuria. A high dose of nitrite also attenuated L-NAME-induced renal injury. These findings suggest that dietary doses of nitrite that protect the kidney are associated with significant increase in iron-nitrosyl-hemoglobin levels. We conclude that dietary nitrite-derived NO generation may serve as a backup system when the nitric oxide synthase/L-arginine-dependent NO generation system is compromised.

American Journal of Physiology, Renal Physiology


Big mitogen-activated protein kinase 1 (BMK1)/extracellular signal regulated kinase 5 (ERK5) is involved in platelet-derived growth factor (PDGF)-induced vascular smooth muscle cell migration

Big mitogen-activated protein kinase 1 (BMK1), also known as extracellular signal-regulated kinase 5 (ERK5), is a newly identified member of the mitogen-activated protein (MAP) kinase family. Recently, several studies have suggested that BMK1 plays an important role in the pathogenesis of cardiovascular disease. To clarify the pathophysiological significance of BMK1 in the process of vascular remodeling, we explored the molecular mechanisms of BMK1 activation in vascular smooth muscle cells (VSMCs). From the results of co-immunoprecipitation and immunoblotting analyses, it was found that platelet-derived growth factor (PDGF), a known potent mitogen, activated BMK1 and triggered the Gab1-SHP-2 interaction in rat aortic smooth muscle cells (RASMCs). The abrogation of SHP-2 phosphatase activity by transfection of the SHP-2-C/S mutant suppressed PDGF-stimulated BMK1 activation. Infection with an adenoviral vector expressing dominant-negative MEK5alpha, which can suppress PDGF-stimulated BMK1 activation to the control level, inhibited PDGF-induced RASMC migration. Moreover, we observed an increase of BMK1 activation in injured mouse femoral arteries. From these findings, it is suggested that BMK1 activation leads to VSMC migration induced by PDGF via Gab1-SHP-2 interaction, and that BMK1-mediated VSMC migration may play a role in the pathogenesis of vascular remodeling.


The novel Src kinase inhibitor M475271 inhibits VEGF-induced vascular endothelial-cadherin and β-catenin phosphorylation but increases their association

M475271, 4-quinazolinamine, N-(2-chloro-5-methoxyphenyl)-6-methoxy-7-[(1-methyl-4-piperidinyl) methoxy]-(9Cl), is a new anilinoquinazoline derivative that displays selective inhibition of Src kinase activity and tumor growth in vivo. Vascular endothelial growth factor (VEGF)-induced angiogenesis plays a pivotal role in tumor growth and metastasis. Vascular endothelial (VE)-cadherin is an endothelial cell-specific adhesion molecule that can interact with the cytoskeleton via several anchoring molecules such as beta-catenin. Here, we examined the effect of M475271 on VE-cadherin and beta-catenin phosphorylation and association. We also examined its effect on VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation, migration, and tube formation. The findings reveal pretreatment with M475271 significantly inhibits VEGF-induced VE-cadherin and beta-catenin phosphorylation. However, M475271 significantly increases VE-cadherin and beta-catenin association compared to the VEGF-treated group. Confocal laser microscopic examination confirmed the augmentation effect of M475271 on VE-cadherin and beta-catenin association. Finally, M475271 was shown to have inhibitory effects comparable to those of PP2 and Herbimycin A on VEGF-induced HUVEC proliferation, migration, and tube formation. These findings suggest that M475271 attenuates VEGF-induced angiogenesis by maintaining cell-cell junction stability. Although the involvement of other signaling molecules cannot be ruled out, M475271 has potential as a drug for the inhibition of the angiogenesis needed for tumor growth and metastasis.


Calcium and reactive oxygen species mediated Zn2+-induced apoptosis in PC12 cells

The release of excessive Zn(2+) from presynaptic boutons into extracellular regions contributes to neuronal apoptotic events, which result in neuronal cell death. However, the mechanisms of Zn(2+)-induced neuronal cell death are still unclear. Therefore, we investigated the dynamics of intracellular Zn(2+), calcium, and reactive oxygen species in PC12 cells. The addition of Zn(2+) produced cell death in a concentration- and time-dependent manner. (45)Ca(2+) influx occurred just after the treatment with Zn(2+), although subsequent hydroxyl radical ((*)OH) production did not begin until 3 h after Zn(2+) exposure. (*)OH production was significantly attenuated in Ca(2+)-free medium or by L-type Ca(2+) channel antagonist treatment, but it was independent of the intracellular Zn(2+) content. Dantrolene treatment had no protective effects against Zn(2+)-induced cell death. Treatment with N-acetyl-L-cysteine blocked (*)OH generation and subsequent cell death. These data indicate that Ca(2+) influx and subsequent (*)OH production are critical events in Zn(2+)-induced toxicity in PC12 cells.


Effects of angiotensin II type 1 receptor blockade on the systemic blood nitric oxide dynamics in Nω-nitro-L-arginine methyl ester-treated rats

We previously succeeded in measuring the nitrosylhemoglobin (HbNO) level as an index of blood nitric oxide (NO) by the electron paramagnetic resonance (EPR) HbNO signal subtraction method. In this study, we examined the effects of olmesartan, an angiotensin II type 1 receptor blocker (ARB), on NO dynamics in N(omega)-nitro-L-arginine methyl ester (L-NAME)-treated rats by the EPR-subtraction method. Oral administration of L-NAME for 2 weeks induced serious hypertension, and the HbNO concentration was reduced to 37.6% of the level in controls. Coadministration of olmesartan improved hypertension and increased the blood HbNO concentration of L-NAME-treated rats. In contrast, coadministration of hydralazine improved hypertension but did not affect the blood HbNO concentration. In conclusion, our findings suggested that chronic administration of olmesartan ameliorated the endothelial dysfunction in L-NAME-treated rats.


Transactivation of fetal liver kinase-1/kinase-insert domain-containing receptor by lysophosphatidylcholine induces vascular endothelial cell proliferation.

Lysophosphatidylcholine (LPC), a major lipid component of oxidized low-density lipoprotein, is a bioactive lipid molecule involved in numerous biological processes including the progression of atherosclerosis. Recently orphan G protein-coupled receptors were identified as high-affinity receptors for LPC. Although several G protein-coupled receptor ligands transactivate receptor tyrosine kinases, LPC-stimulated transactivation of receptor tyrosine kinase has not yet been reported. Here we observed for the first time that LPC treatment of human umbilical vein endothelial cells (HUVECs) induces tyrosyl phosphorylation of vascular endothelial growth factor receptor 2 [fetal liver kinase-1/kinase-insert domain-containing receptor, Flk-1/KDR)]. Flk-1/KDR transactivation by LPC was inhibited by vascular endothelial growth factor receptor tyrosine kinase inhibitors, SU1498 and 4-[(4'-chloro-2'-fluoro) phenylamino]6,7-dimethoxyquinazoline (VTKi) in immunoprecipitation. Furthermore, we examined the effects of the Src family kinases inhibitors, herbimycin A and 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo[3,4-d] pyrimidine (PP2), on LPC-induced Flk-1/KDR transactivation. Results from Western blots, c-Src is involved in LPC-induced Flk-1/KDR transactivation because herbimycin A and PP2 inhibited this transactivation. Kinase-inactive (KI) Src transfection also inhibited LPC-induced Flk-1/KDR transactivation. In addition, results from Western blots, ERK1/2 and Akt, which are downstream effectors of Flk-1/KDR, were also activated by LPC, and this was inhibited by SU1498, VTKi, herbimycin A, PP2, and KI Src transfection in HUVECs. LPC-induced stimulation of HUVEC proliferation was shown to be secondary to transactivation because it was suppressed by SU1498, VTKi, herbimycin A, PP2, and KI Src transfection in dimethylthiazoldiphenyltetra-zoliumbromide assay. These findings suggest that LPC-induced Flk-1/KDR transactivation via c-Src may have important implications for the progression of atherosclerosis.


ERK1/2 activation by angiotensin II inhibits insulin-induced glucose uptake in vascular smooth muscle cells

Clinical evidence suggests a relationship between hypertension and insulin resistance, and cross-talk between angiotensin II (Ang II) and insulin signaling pathways may take place. We now report the effect of Ang II on insulin-induced glucose uptake and its intracellular mechanisms in vascular smooth muscle cells (VSMC). We examined the translocation of glucose transporter-4 (GLUT-4) and glucose uptake in rat aortic smooth muscle cells (RASMC). Mitogen-activated protein (MAP) kinases and Akt activities, and phosphorylation of insulin receptor substrate-1 (IRS-1) at the serine and tyrosine residues were measured by immunoprecipitation and immunoblotting. As a result, Ang II inhibited insulin-induced GLUT-4 translocation from cytoplasm to the plasma membrane in RASMC. Ang II induced extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) activation and IRS-1 phosphorylation at Ser307 and Ser616. Ang II-induced Ser307 and Ser616 phophorylation of IRS-1 was inhibited by a MEK inhibitor, PD98059, and a JNK inhibitor, SP600125. Ang II inhibition of insulin-stimulated IRS-1 tyrosyl phophorylation and Akt activation were reversed by PD98059 but not by SP600125. Ang II inhibited insulin-induced glucose uptake, which was also reversed by PD98059 but not by SP600125. It is shown that Ang II-induced ERK1/2 activation inhibits insulin-dependent glucose uptake through serine phophorylation of IRS-1 in RASMC.


Aldosterone stimulates vascular smooth muscle cell proliferation via big mitoten-activated protein kinase 1 activation

The nongenomic effects of aldosterone have been implicated in the pathogenesis of various cardiovascular diseases. Aldosterone-induced nongenomic effects are attributable in part to the activation of extracellular signal-regulated kinase 1/2 (ERK1/2), a classical mitogen-activated protein (MAP) kinase. Big MAP kinase 1 (BMK1), a newly identified MAP kinase, has been shown to be involved in cell proliferation, differentiation, and survival. We examined whether aldosterone stimulates BMK1-mediated proliferation of cultured rat aortic smooth muscle cells (RASMCs). Mineralocorticoid receptor (MR) expression and localization were evaluated by Western blotting analysis and fluorolabeling methods. ERK1/2 and BMK1 activities were measured by Western blotting analysis with the respective phosphospecific antibodies. Cell proliferation was determined by Alamar Blue colorimetric assay. Aldosterone (0.1 to 100 nmol/L) dose-dependently activated BMK1 in RASMCs, with a peak at 30 minutes. To clarify whether aldosterone-induced BMK1 activation is an MR-mediated phenomenon, we examined the effect of eplerenone, a selective MR antagonist, on aldosterone-induced BMK1 activation. Eplerenone (0.1 to 10 micromol/L) dose-dependently inhibited aldosterone-induced BMK1 activation in RASMCs. Aldosterone also stimulated RASMC proliferation, which was inhibited by eplerenone. Aldosterone-mediated phenomena were concluded to be attributable to a nongenomic effect because cycloheximide failed to inhibit aldosterone-induced BMK1 activation. Transfection of dominant-negative MAP kinase/ERK kinase 5 (MEK5), which is an upstream regulator of BMK1, partially inhibited aldosterone-induced RASMC proliferation, which was almost completely inhibited by MEK inhibitor PD98059. In addition to the classical steroid activity, rapid nongenomic effects induced by aldosterone may represent an alternative etiology for vascular diseases such as hypertension.


A Novel Src Kinase Inhibitor, M475271, Inhibits VEGF-Induced Human Umbilical Vein Endothelial Cell Proliferation and Migration

Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that plays a pivotal role in both physiological and pathological angiogenesis. M475271, 4-quinazolinamine, N-(2-chloro-5-methoxyphenyl)-6-methoxy-7-[(1-methyl-4-piperidinyl) methoxy]-(9Cl), is a new anilinoquinazoline derivative that showed selective inhibition of Src kinase activity and tumor growth in vivo. Here, we examined the effect of M475271 on VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation and migration and their intracellular mechanisms. Our findings showed that M475271 pretreatment resulted in a significant inhibition of VEGF-induced HUVEC proliferation, [(3)H]thymidine incorporation, and migration. M475271 inhibited VEGF-induced Flk-1 and Src phosphorylation and their association. Confocal laser microscopic examination confirmed the inhibitory effect of M475271 on VEGF-induced Flk-1/Src association. M475271 inhibited VEGF-induced extracellular signal-regulated kinase1/2 (ERK1/2) and p38 but not Akt activation in a concentration-dependent manner. M475271, PI3-K inhibitor, and p38 inhibitor inhibited VEGF-induced HUVEC proliferation and migration. However, a MEK1/2 inhibitor inhibited VEGF-induced proliferation but not migration. These findings suggest that M475271 attenuates VEGF-induced HUVEC proliferation and migration through the inhibition of signaling pathways involving Src, ERK1/2, and/or p38. Taken together, these data indicate that M475271 may be a useful candidate for inhibition of endothelial cell proliferation and migration relevant to angiogenesis.


徳島大学病院におけるTPN処方設計支援ソフトの使用評価と改良

徳島大学病院におけるTPN処方設計支援ソフトの使用評価と改良

Fluid therapy is a fundamental treatment for almost all inpatients, and nutritional therapy is the most important type of such therapy. Currently, total parenteral nutrition (TPN) is widely used to provide complete nutritional support but 30-40% of TPN recipients are considered to in a malnourished state due to inappropriate TPN prescriptions. Computer-assisted TPN prescription systems are thought to be useful to clinical professionals in solving this problem because they can perform complicated calculations that make it easy to draw up correct TPN prescriptions. So, we made a prototype system for aiding the preparation of TPN prescriptions based on Microsoft^[ !R] EXCEL and it was tested by physicians, pharmacists, dietitians and nurses engaged in TPN therapy at Tokushima University Hospital. We also had them fill out a questionnaire on the system in which they rated it for ease of operation and usefulness according to a scoring system in which 5 indicated full marks. Our Computer-Assisted TPN Prescription System was improved on the basis of the questionnaire results and is now being effectively used by the nutrition support team (NST) in Tokushima University Hospital.

Japanese Journal of Pharmaceutical Health Care and Sciences


Antioxidant effects of stereoisomers of N-acetylcysteine (NAC), L-NAC and D-NAC, on angiotensin II-stimulated MAP kinase activation and vascular smooth muscle cell proliferation

We examined the effects of the stereoisomers of N-acetylcysteine (NAC), L-NAC and D-NAC, on cellular glutathione (GSH) concentration and whether NAC-regulated cellular GSH levels are directly associated with angiotensin II (Ang II)-induced intracellular signaling events in vascular smooth muscle cells (VSMC). Both L-NAC and D-NAC similarly increased intracellular GSH concentration. We found that L-NAC and D-NAC both inhibited Ang II-induced c-Jun N-terminal kinase and p38 mitogen-activated protein kinase activation and [(3)H]-thymidine incorporation in VSMC. Our present study indicates the comparable effects of NAC stereoisomers in regulating intracellular GSH and the redox-dependent intracellular signaling mechanisms in VSMC.


Dual effects of endothelin-1 (1-31): induction of mesangial cell migration and facilitation of monocyte recruitment through monocyte chemoattractant protein-1 production by mesangial cells

We previously found that human chymase selectively cleaves big endothelin-1 (ET-1) at the Tyr31-Gly32 bond and produces 31-amino acid endothelins, ET-1 (1-31), without any further degradation products. In this study, we investigated the effect of ET-1 (1-31) on the migration of cultured rat mesangial cells (RMCs) and on cells of the human monocytic cell line, THP-1. In addition, we examined the interaction between RMCs and THP-1 cells using conditioned media from ET-1 (1-31)-stimulated RMCs. ET-1 (1-31) caused an increase in RMC migration in a concentration-dependent manner, and the degree of increase was similar to those by ET-1 and angiotensin II (All). The ET-1 (1-31)-induced increase in RMC migration was inhibited by BQ123, an endothelin ETA receptor antagonist, but not by BQ788, an endothelin ETB receptor antagonist. ET-1 (1-31) alone did not cause significant migration of THP-1 cells. However, significant recruitment of THP-1 cells was observed with conditioned media taken from ET-1 (1-31)-stimulated RMCs. The conditioned media-induced migration of THP-1 cells was inhibited by BQ123, but not by BQ788. Western blotting analysis of the lysate of RMCs revealed that the expression of monocyte chemoattractant protein-1 (MCP-1) protein in RMCs was increased by treatment with ET-1 (1-31). The addition of neutralizing antibody for MCP-1 to the medium inhibited the migration of THP-1 cells induced by conditioned media from ET-1 (1-31)-stimulated RMCs. These findings suggest that ET-1 (1-31) play a role in glomerulonephritis (GN) via dual effects that directly cause the migration of mesangial cells (MCs) and may be responsible for the recruitment of mononuclear cells mediated through the activation of MCs. Since human chymase has been reported to be involved in glomerular disease, ET-1 (1-31) may be among the mediators.


Inhibitory action of novel arginine derivative on catecholamine secretion evoked by acetylcholine from cultured bovine adrenal chromaffin cells

A novel product, 4-amino-5-guanidinopentanoic acid 15-[(4-aminobutyl)-3-aminopropylcarbamoyl] pentadecyl ester (Arg-HSA-Spm), was synthesized based on ptilomycalin A, which is one of the extracts from marine sponge. Arg-HSA-Spm contains arginine in its chemical structure. The pharmacological action of Arg-HSA-Spm on catecholamine secretion from cultured bovine adrenal chromaffin cells was examined. Arg-HSA-Spm inhibited catecholamine secretion stimulated by the physiological secretagog acetylcholine. This inhibitory action of Arg-HSA-Spm on catecholamine secretion induced by 10(-4) M acetylcholine was dose-dependent from 10(-8) M to 10(-5) M. In the presence of 3 x 10(-7) M Arg-HSA-Spm, the stimulation of catecholamine secretion observed by increasing acetylcholine up to 10(-3) M did not reach the maximal level observed without Arg-HSA-Spm. Arg-HSA-Spm at 10(-5) M suppressed both the increase in intracellular free Ca2+ level and the influx of 45Ca2+ induced by 10(-4) M acetylcholine. The Arg-HSA-Spm-induced suppression of intracellular free Ca2+ level, the influx of 45Ca2+ and catecholamine secretion were not observed in the presence of extracellular K+ at 56 mM. The results presented in this study suggested that Arg-HSA-Spm may inhibit the influx of extracellular Ca2+ into the cells, probably through its blocking action related to acetylcholine receptors, resulting in the inhibition of catecholamine secretion in adrenal chromaffin cells.


Ebselen attenuates oxidative styress-induced apoptosis via the inhibition of the c jun N-terminal kinase and activator protein-1 signaling pathway in PC12 cells.

1: Ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one) is a selenoorganic compound exhibiting both glutathione peroxidase activity and antioxidant activity. Although it has been reported that ebselen is effective for oxidative stress-induced neuronal damage both in vivo and clinically, the precise mechanisms of the efficacy have not yet been elucidated. Thus, we hypothesized that ebselen may affect reactive oxygen species-induced mitogen-activated protein (MAP) kinase activation in cultured PC12 cells. 2: Our findings showed that hydrogen peroxide (H(2)O(2)) stimulated rapid and significant activation of extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK) and p38 in PC12 cells, which is a model of catecholamine-containing neurons. 3: H(2)O(2)-induced JNK activation was inhibited by ebselen, whereas ERK1/2 and p38 activation by H(2)O(2) were not affected by ebselen. 4: Inhibition by ebselen of H(2)O(2)-induced hydroxyl radical generation in PC12 cells was observed using electron paramagnetic resonance measurements. Ebselen also inhibited H(2)O(2)-induced increases in DNA binding activity of activator protein-1 (AP-1), a downstream transcription factor of JNK, composed of the c-Jun homo/heterodimer. 5: Finally, pretreatment of cells with ebselen resulted in a significant recovery from cell death including apoptosis by H(2)O(2) in PC12 cells. 6 These findings suggest that ebselen attenuates oxidative stress-induced neuronal cell death through the inhibition of the JNK and AP-1 signalling pathway. Thus, inhibition of JNK by ebselen may imply its usefulness for treatment of ischaemic cerebral diseases relevant to neuronal cell death.


Effects of losartan in combination with or without exercise on insulin resistance in Otsuka Long-Evans Tokushima Fatty rats.

Hypertension often complicates type 2 diabetes mellitus, and angiotensin converting enzyme inhibitor treatment has been shown to improve insulin resistance in such cases. However, the effect of angiotensin II type-1 (AT(1)) receptor antagonists on insulin resistance is still controversial. To gain further information on this effect, we examined the effect of losartan on insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of type 2 diabetes mellitus. Losartan administration alone lowered systolic blood pressure, but did not improve oral glucose tolerance test or insulin resistance in OLETF rats. However, the administration of losartan with exercise significantly improved both systolic blood pressure and insulin resistance relative to control OLETF rats. On the other hand, losartan treatment, regardless of exercise, increased glucose uptake in excised soleus muscle and fat cells. To explore the beneficial effect of losartan on skeletal muscle glucose uptake, we examined intracellular signaling of soleus muscle. Although Akt activity and glucose transporter type 4 (GLUT4) expressions were not affected by losartan with or without exercise, extracellular signal-regulated kinase (ERK1/2) and p38 mitogen-activated protein (MAP) kinase activities were increased by both interventions. These results indicate that angiotensin AT(1) receptor antagonist improved local insulin resistance, but not systemic insulin resistance. These findings may explain the controversy over the effect of angiotensin AT(1) receptor antagonists on insulin resistance in clinical use. The enhancing effect of angiotensin AT(1) receptor antagonist on skeletal muscle glucose uptake may be attributable to MAP kinase activation or other mechanisms rather than phosphatidylinositol 3-kinase activation.


Effect of mometasone furoate by topical application on allergic rhinitis model in rats

The effects of mometasone furoate on experimental allergic rhinitis in rats were studied in comparison with that of fluticasone propionate. Topical application of both drugs inhibited dose-dependently the increase of nasal symptoms (sneezing and nasal rubbing) after antigen challenge to the nasal cavity of actively sensitized rats. Mometasone furoate and fluticasone propionate at concentrations of 0.01 or 0.1% significantly inhibited both nasal rubbing and sneezing 1 h after topical application of both drugs. The relative potencies of mometasone furoate in nasal rubbing and sneezing compared to fluticasone propionate were 5.01 and 6.87, respectively. Mometasone furoate (0.02%) and fluticasone propionate (0.1%) significantly inhibited the increase of antigen-induced nasal rubbing even 6 h after topical application, indicating that both drugs have a long-lasting effect.


Participation of GABAergic and histaminergic systems in inhibiting amygdaloid kindled seizures


Effects of levocabastine on lipid mediator release from guinea pig lung fragments

The effects of levocabastine, a novel histamine H1-receptor antagonist, on lipid mediator release induced by antigen-antibody reaction from actively sensitized guinea pig lung fragments were studied. Levocabastine dose-dependently inhibited the release of leukotriene C4 from guinea pig lung fragments induced by antigen. A significant effect was observed with levocabastine at a concentration of 10(-4) M. On the other hand, levocabastine produced no effect on the release of leukotriene E4 or thromoboxane B2. From these findings, it was concluded that levocabastine may be useful for relieving the nasal obstruction in allergic rhinitis caused by inhibition of leukotriene C4 release.


Anticonvulsant properties of 1,4-benzodiazepine derivatives in amygdaloid-kindled seizures and their chemical structure-related anticonvulsant action

The effects of 14 different 1,4-benzodiazepines on amygdaloid-kindled seizures and their chemical structure-related anticonvulsive actions were studied. The prophylactic effects of 1, 4-benzodiazepines on amygdaloid-kindled seizures were also examined. Male Wistar strain rats were used in this study. Rats were anesthetized with pentobarbital sodium (35 mg/kg i.p.) and bipolar electrodes were implanted into the right amygdala. The stimulating parameters were 1 ms pulse duration, 60 Hz frequency and a 1 s duration at an intensity just sufficient to induce afterdischarge (AD). All the 1,4-benzodiazepines depressed both seizure stage and AD duration of amygdaloid-kindled seizures. Of the 1, 4-benzodiazepines, prazepam, flutoprazepam and flurazepam with a long alkyl chain at position 1 were less effective than the drugs having a hydrogen or methyl group at the same position. Nitrazepam, nimetazepam, flunitrazepam and clonazepam which have a nitro group at position 7 showed more potent antiepileptic activity than the drugs with a chloro group. Certain 1,4-benzodiazepines caused inhibition of the development of amygdaloid-kindled seizures. The existence of a hydrogen or methyl group at position 1 and a nitro group at position 7 is important for exhibiting potent anticonvulsant activity in amygdaloid-kindled seizures. Introduction of an oxygen group at position 2 is also necessary for high activity. 1,4-benzodiazepines had not only therapeutic but also prophylactic effects on amygdaloid-kindled seizures.


The effects of histamine H3-receptor antagonists on amygdaloid kindled seizures in rats


Histaminergic mechanisms in amygdaloid-kindled seizures in rats


Development of hydrogen peroxide-responsive amide bond cleavage device


Design and synthesis of hypoxia-responsive amino acid which causes peptide bond cleavage in hypoxic cells


Atenolol and mortality events in patients with chronic kidney disease: Analysis of data from the Japanese Adverse Drug Event Report database.

Basic & Clinical Pharmacology & Toxicology


Fluoropyridmidine use and hypertriglyceridemia among Japanese patients: analysis of adverse event database.

Background The association between fluoropyrimidines except for capecitabine and the risk of hypertriglyceridemia is unclear. Objective To investigate hypertriglyceridemia in patients receiving fluoropyrimidines. Method This observational study used anonymized patient data recorded in the open-access Japanese Adverse Drug Event Report database. All fluoropyrimidine and taxane users were investigated. Results We identified 29,451 fluoropyrimidine users and 21,266 taxane users. Disproportionality for both hypertriglyceridemia and an increase in serum triglyceride levels was observed in fluoropyrimidine users compared with in taxane users (reporting odds ratio, 6.74; 95% confidence interval [CI] 2.05-22.17; P < .001). Multivariate logistic analysis showed that both hypertriglyceridemia and an increase in serum triglyceride levels among fluoropyrimidines users were significantly associated with doxifluridine use (odds ratio [OR] 42.50; 95% CI 5.34-338.00; P < .001), tegafur use (OR 9.56; 95% CI 2.08-43.90; P < .001), capecitabine use (OR 12.30; 95% CI 2.67-56.80; P < .001), and breast cancer (OR 5.61; 95% CI 1.07-29.50; P = .042). Conclusion This study suggests that the use of tegafur and doxifluridine is associated with an increased risk of hypertriglyceridemia similar to that with the use of capecitabine; in particular, fluoropyrimidine users with breast cancer may have a high risk of hypertriglyceridemia.

International Journal of Clinical Pharmacy