The role of antipsychotics and other drugs on the development and progression of neuroleptic malignant syndrome.

Neuroleptic malignant syndrome (NMS) is a rare but serious and sometimes fatal complication in patients taking antipsychotic drugs, and its underlying mechanism still remains unclear. The pharmacotherapy for psychotic disorders is complicated and often involves a combination of two or more drugs, including drugs other than antipsychotics. In the present study, we used the Japanese Adverse Drug Event Report (JADER) database to broadly investigate the drugs associated with NMS, following their related pathways, as well as the drug-drug interactions (DDIs) in NMS. All analyses were performed using data from the JADER database from April 2004 to May 2022. Single-drug signals were evaluated using the reporting odds ratio (ROR) and proportional reporting ratio (PRR), and drug pathways were investigated using the Kyoto Encyclopedia of Genes and Genomes (KEGG). DDIs were evaluated using the Ω shrinkage measure and Chi-square statistics models. All drugs associated with 20 or more NMS cases in the JADER database exhibited signals for NMS, including non-antipsychotics. Pathways associated with the drugs included the dopaminergic or serotonergic synapses related to antipsychotics. DDIs leading to NMS were confirmed for several drug combinations exhibiting single-drug signals. This study confirmed the significant association of various drugs, including non-psychotics, with NMS and suggested that various pathways related to these drugs may be involved in the progression of NMS. In addition, several combinations of these drugs were found to interact (DDI), increasing the risk of NMS, which suggests that appropriate caution should be taken when administering these drugs.

Analysis of Appendicitis Cases in the Japanese Adverse Drug Event Report (JADER) Database.

Appendicitis is one of the most common abdominal surgical emergencies worldwide; however, its causes remain poorly understood. The Japanese Adverse Drug Event Report (JADER) database is a spontaneous reporting system (SRS) that can be utilized to analyze the safety signals of adverse events. In this study, we investigated the association between drug use and the onset of appendicitis using the JADER database. We first used the reporting odds ratio (ROR) as the signal and found signals for appendicitis, perforated appendicitis, and complicated appendicitis for 23, 9, and 1 drug, respectively. To investigate the level of hazard over time in drug-associated appendicitis, the Weibull shape parameter ß was calculated using a Weibull plot, which revealed drug-dependent patterns for changes in the risk of appendicitis over time for the eight drugs. Furthermore, logistic regression analysis was performed to account for the influence of age, sex, and primary disease, and a significant association was detected between two drugs and appendicitis. Several types of drugs, such as antitumor, antirheumatic, and anti-inflammatory drugs, were included in our analyses; however, only clozapine, which is used for patients with schizophrenia, was commonly identified in these analyses. The resulting data suggest that certain drugs may be associated with appendicitis and may require adequate attention.

Upregulation of iNOS Protects Cyclic Mechanical Stretch-Induced Cell Death in Rat Aorta Smooth Muscle Cells.

Aortic dissection and aneurysm are associated with abnormal hemodynamic loads originating from hypertension. Our previous study demonstrated that cyclic mechanical stretch (CMS, mimicked hypertension) caused the death of rat aortic smooth muscle cells (RASMCs) in a mitogen activated-protein kinases (MAPKs)-dependent manner. The current study investigated the effects of inducible nitric oxide synthase (iNOS) on CMS-induced RASMC death. cDNA microarrays for CMS-treated RASMCs showed that iNOS expression levels were increased in response to CMS. Real-time polymerase chain reaction (PCR) analysis demonstrated that this increase was p38 MAPK (p38)-dependent. NO production was also increased. This increase could be inhibited by p38 and iNOS inhibitors. Thus, CMS-induced iNOS synthesized NO. CMS-induced cell death in RASMCs was increased by the iNOS inhibitor but abrogated by the long-acting NO donor DETA-NONOate. Increased iNOS expression was confirmed in the abdominal aortic constriction mouse model. Signal transducers and activators of transcription 1 (STAT1) was activated in stretched RASMCs, and iNOS expression and NO production were inhibited by the STAT1 inhibitor nifuroxazide. Our findings suggest that RASMCs were protected by iNOS from CMS-stimulated cell death through the STAT1 and p38 signal pathways independently.

Proliferative Pathways of Vascular Smooth Muscle Cells in Response to Intermittent Hypoxia.

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia (IH) and is a risk factor for cardiovascular diseases (e.g., atherosclerosis) and chronic inflammatory diseases (CID). The excessive proliferation of vascular smooth muscle cells (VSMCs) plays a pivotal role in the progression of atherosclerosis. Hypoxia-inducible factor-1 and nuclear factor-κB are thought to be the main factors involved in responses to IH and in regulating adaptations or inflammation pathways, however, further evidence is needed to demonstrate the underlying mechanisms of this process in VSMCs. Furthermore, few studies of IH have examined smooth muscle cell responses. Our previous studies demonstrated that increased interleukin (IL)-6, epidermal growth factor family ligands, and erbB2 receptor, some of which amplify inflammation and, consequently, induce CID, were induced by IH and were involved in the proliferation of VSMCs. Since IH increased IL-6 and epiregulin expression in VSMCs, the same phenomenon may also occur in other smooth muscle cells, and, consequently, may be related to the incidence or progression of several diseases. In the present review, we describe how IH can induce the excessive proliferation of VSMCs and we develop the suggestion that other CID may be related to the effects of IH on other smooth muscle cells.

Intermittent hypoxia-induced epiregulin expression by IL-6 production in human coronary artery smooth muscle cells.

Patients with obstructive sleep apnea (OSA) experience repetitive episodes of desaturation and resaturation of blood oxygen (known as intermittent hypoxia or IH), during sleep. We showed previously that IH induced excessive proliferation of rat vascular smooth muscle cells through upregulation of members of the epidermal growth factor family, especially epiregulin (EREG), and the erbB2 receptor. In this study, we exposed human coronary artery smooth muscle cells to IH and found that IH significantly increased the expression of EREG. IH increased the production of interleukin-6 (IL-6) in smooth muscle cells, and the addition of IL-6 induced EREG expression. Small interfering RNA for IL-6 or IL-6 receptor attenuated the IH-induced increase in EREG. IL-6 may play a pivotal role in EREG upregulation by IH and consequently OSA-related atherosclerosis.

[Vascular smooth muscle cell response to cyclic mechanical stretch and aortic dissection].

Acute aortic dissection is the most common life-threatening vascular disease, with sudden onset of severe pain and a high fatality rate. The pulsatile nature of blood flow exposes vascular smooth muscle cells (VSMCs) in the vessel wall to cyclic mechanical stretch (CMS), which evokes VSMC death, phenotypic switching, and migration, leading to aortic dissection. We have revealed that CMS of rat aortic smooth muscle cells (RASMCs) caused JNK- and p38-dependent cell death and that a calcium channel blocker, azelnidipine and an angiotensin II receptor antagonist, olmesartan decreased the phosphorylation of JNK and p38 and, subsequently, decreased cell death by CMS. JNK and p38 inhibitors also inhibited CMS-induced cell death. In addition, we showed that the expression of Cxcl1 and Cx3cl1 chemokines was induced by CMS in a JNK-dependent manner. Expression of Cxcl1 was also induced in VSMCs by hypertension produced by abdominal aortic constriction in mouse. In addition, antagonists against the receptors for CXCL1 and CX3CL1 increased cell death, indicating that CXCL1 and CX3CL1 protect RASMCs from CMS-induced cell death. We also revealed that STAT1 is activated in RASMCs subjected to CMS. Taken together, these results indicate that CMS of VSMCs induces inflammation-related gene expression, including that of CXCL1 and CX3CL1, and activates JNK and p38 MAP kinases, which may play important roles in the stress response against CMS caused by acute rise in blood pressure.

Exendin-4 Prevents Vascular Smooth Muscle Cell Proliferation and Migration by Angiotensin II via the Inhibition of ERK1/2 and JNK Signaling Pathways.

Angiotensin II (Ang II) is a main pathophysiological culprit peptide for hypertension and atherosclerosis by causing vascular smooth muscle cell (VSMC) proliferation and migration. Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, is currently used for the treatment of type-2 diabetes, and is believed to have beneficial effects for cardiovascular diseases. However, the vascular protective mechanisms of GLP-1 receptor agonists remain largely unexplained. In the present study, we examined the effect of exendin-4 on Ang II-induced proliferation and migration of cultured rat aortic smooth muscle cells (RASMC). The major findings of the present study are as follows: (1) Ang II caused a phenotypic switch of RASMC from contractile type to synthetic proliferative type cells; (2) Ang II caused concentration-dependent RASMC proliferation, which was significantly inhibited by the pretreatment with exendin-4; (3) Ang II caused concentration-dependent RASMC migration, which was effectively inhibited by the pretreatment with exendin-4; (4) exendin-4 inhibited Ang II-induced phosphorylation of ERK1/2 and JNK in a pre-incubation time-dependent manner; and (5) U0126 (an ERK1/2 kinase inhibitor) and SP600125 (a JNK inhibitor) also inhibited both RASMC proliferation and migration induced by Ang II stimulation. These results suggest that exendin-4 prevented Ang II-induced VSMC proliferation and migration through the inhibition of ERK1/2 and JNK phosphorylation caused by Ang II stimulation. This indicates that GLP-1 receptor agonists should be considered for use in the treatment of cardiovascular diseases in addition to their current use in the treatment of diabetes mellitus.

Olmesartan inhibits cultured rat aortic smooth muscle cell death induced by cyclic mechanical stretch through the inhibition of the c-Jun N-terminal kinase and p38 signaling pathways.

Acute aortic dissection (AAD) is a life-threating disease; however, there is almost no effective pharmacotherapy for it. An increase in c-Jun N-terminal kinase (JNK) phosphorylation and smooth muscle cell (SMC) apoptosis is observed tissues in patients with AAD. Therefore, we hypothesized that an acute rise in blood pressure leads to SMC death through phosphorylation of JNK or p38, which may cause AAD. We investigated the influence of cyclic mechanical stretch, which mimics an acute increase in blood pressure, on cultured rat aortic SMCs (RASMCs) and examined the changes in JNK and p38 phosphorylation. Further, we investigated the effect of olmesartan, an angiotensin II receptor blocker, on stretch-induced RASMC death. We found that mechanical stretch-induced RASMC death in a time-dependent manner, which correlated with the phosphorylation of JNK and p38. Olmesartan inhibited RASMC death and the phosphorylation of JNK and p38. JNK and p38 inhibitors reversed stretch-induced RASMC death. These results suggest that acute mechanical stretch causes JNK and p38 phosphorylation, which may result in SMC death leading to aortic dissection. Olmesartan may be used for pharmacotherapy to prevent aortic dissection, independent of its blood pressure-lowering effect, through its inhibition of JNK and p38 phosphorylation.

Azelnidipine inhibits cultured rat aortic smooth muscle cell death induced by cyclic mechanical stretch.

Acute aortic dissection is the most common life-threatening vascular disease, with sudden onset of severe pain and a high fatality rate. Clarifying the detailed mechanism for aortic dissection is of great significance for establishing effective pharmacotherapy for this high mortality disease. In the present study, we evaluated the influence of biomechanical stretch, which mimics an acute rise in blood pressure using an experimental apparatus of stretching loads in vitro, on rat aortic smooth muscle cell (RASMC) death. Then, we examined the effects of azelnidipine and mitogen-activated protein kinase inhibitors on mechanical stretch-induced RASMC death. The major findings of the present study are as follows: (1) cyclic mechanical stretch on RASMC caused cell death in a time-dependent manner up to 4 h; (2) cyclic mechanical stretch on RASMC induced c-Jun N-terminal kinase (JNK) and p38 activation with peaks at 10 min; (3) azelnidipine inhibited RASMC death in a concentration-dependent manner as well as inhibited JNK and p38 activation by mechanical stretch; and (4) SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor) protected against stretch-induced RASMC death; (5) Antioxidants, diphenylene iodonium and tempol failed to inhibit stretch-induced RASMC death. On the basis of the above findings, we propose a possible mechanism where an acute rise in blood pressure increases biomechanical stress on the arterial walls, which induces RASMC death, and thus, may lead to aortic dissection. Azelnidipine may be used as a pharmacotherapeutic agent for prevention of aortic dissection independent of its blood pressure lowering effect.

Intermittent hypoxia induces the proliferation of rat vascular smooth muscle cell with the increases in epidermal growth factor family and erbB2 receptor.

Obstructive sleep apnea is characterized by intermittent hypoxia (IH), and associated with cardiovascular diseases, such as stroke and heart failure. These cardiovascular diseases have a relation to atherosclerosis marked by the proliferation of vascular smooth muscle cells (VSMCs). In this study, we investigated the influence of IH on cultured rat aortic smooth muscle cell (RASMC). The proliferation of RASMC was significantly increased by IH without changing the level of apoptosis. In order to see what induces RASMC proliferation, we investigated the influence of normoxia (N)-, IH- and sustained hypoxia (SH)-treated cell conditioned media on RASMC proliferation. IH-treated cell conditioned medium significantly increased RASMC proliferation compared with N-treated cell conditioned medium, but SH-treated cell conditioned medium did not. We next investigated the epidermal growth factor (EGF) family as autocrine growth factors. Among the EGF family, we found significant increases in mRNAs for epiregulin (ER), amphiregulin (AR) and neuregulin-1 (NRG1) in IH-treated cells and mature ER in IH-treated cell conditioned medium. We next investigated the changes in erbB family receptors that are receptors for ER, AR and NRG1, and found that erbB2 receptor mRNA and protein expressions were increased by IH, but not by SH. Phosphorylation of erbB2 receptor at Tyr-1248 that mediates intracellular signaling for several physiological effects including cell proliferation was increased by IH, but not by SH. In addition, inhibitor for erbB2 receptor suppressed IH-induced cell proliferation. These results provide the first demonstration that IH induces VSMC proliferation, and suggest that EGF family, such as ER, AR and NRG1, and erbB2 receptor could be involved in the IH-induced VSMC proliferation.

S-nitrosylation regulates mitochondrial quality control via activation of parkin.

Parkin, a ubiquitin E3 ligase of the ring between ring fingers family, has been implicated in mitochondrial quality control. A series of recent reports have suggested that the recruitment of parkin is regulated by phosphorylation. However, the molecular mechanism that activates parkin to induce mitochondrial degradation is not well understood. Here, and in contrast to previous reports that S-nitrosylation of parkin is exclusively inhibitory, we identify a previously unrecognized site of S-nitrosylation in parkin (Cys323) that induces mitochondrial degradation. We demonstrate that endogenous S-nitrosylation of parkin is in fact responsible for activation of its E3 ligase activity to induce aggregation and degradation. We further demonstrate that mitochondrial uncoupling agents result in denitrosylation of parkin, and that prevention of denitrosylation restores mitochondrial degradation. Our data indicates that NO both positive effects on mitochondrial quality control, and suggest that targeted S-nitrosylation could provide a novel therapeutic strategy against Parkinson's disease.

Role of big mitogen-activated protein kinase 1 (BMK1) / extracellular signal-regulated kinase 5 (ERK5) in the pathogenesis and progression of atherosclerosis.

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. BMK1 has been reported to be sensitive to various neuro-humoral factors and oxidative stress in various cells. In this review, we focused on the role of BMK1 in atherosclerosis in a cultured rat aortic smooth muscle cell model. Treatment with platelet-derived growth factor caused vascular smooth muscle cell (VSMC) migration in a BMK1 activation-dependent manner. H(2)O(2) caused BMK1 activation and VSMC death, including apoptosis of VSMCs. An inhibitory function for BMK1 against cell death from oxidative stress was discovered using siRNA techniques to downregulate the expression of BMK1. These findings suggest a role for BMK1 in the pathogenesis and/or progression of atherosclerosis.

Prevention of the wortmannin-induced inhibition of phosphoinositide 3-kinase by sulfhydryl reducing agents.

The effects of the sulfhydryl reducing agents 2-mercaptoethanol and dithiothreitol on wortmannin-induced inhibition of phosphoinositide 3-kinase (PI3K) were studied in order to examine whether the sulfhydryl reducing agents directly affect the wortmannin inhibition of PI3K. These reducing agents are commonly used to stabilize enzyme structures by maintaining protein sulfhydryl groups in the reduced state. Preincubation of wortmannin with millimolar levels of 2-mercaptoethanol, a sulfhydryl derivative of ethanol, markedly prevented subsequent wortmannin-induced inhibition of PI3K. In contrast, ethanol, 2-mercaptoethanol lacking sulfhydryl group, and 2-(methylthio)ethanol, a methyl derivative of the sulfhydryl group of 2-mercaptoethanol, had little effect on the wortmannin-induced inhibition of PI3K, which suggests that the prevention of wortmannin-induced inhibition by 2-mercaptoethanol occurs through the sulfhydryl group of this agent. Moreover, dithiothreitol, a second sulfhydryl reducing agent, also markedly prevented wortmannin-induced inhibition of PI3K. These results indicate that the wortmannin-induced inhibition of PI3K is markedly prevented by millimolar concentrations of sulfhydryl reducing agents such as 2-mercaptoethanol and dithiothreitol in the medium, presumably by the binding of wortmannin to the agents.

Big mitogen-activated protein kinase 1 protects cultured rat aortic smooth muscle cells from oxidative damage.

Oxidative stress is considered a major mediator of arteriosclerosis. In vascular smooth muscle cells, oxidative stress-induced cell death (including apoptosis) is probably related to arterial calcification in arteriosclerosis. Big mitogen-activated protein kinase-1 / extracellular signal-regulated kinase 5 (BMK1/ERK5) is a newly identified member of the mitogen-activated protein kinases family. Like Src tyrosine kinase, BMK1/ERK5 is known to be sensitive to oxidative stress; however, its pathophysiological significance is poorly understood. In this study, we investigated the involvement of BMK1 and Src in H(2)O(2)-induced cell death using cultured rat aortic smooth muscle cells (RASMCs). Cell apoptosis was evaluated by using the TdT-mediated dUTP nick end labeling (TUNEL) method, and BMK1 and Src activities were determined by Western blotting. The main results are as follows: 1) BMK1 and Src were activated by H(2)O(2) in a time- and concentration-dependent manner in RASMCs; 2) BMK1 activation by H(2)O(2) was attenuated both in Src-knockdown RASMCs and in RASMCs pretreated with 4-amino-5-(4-chloro-phenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2), a Src family kinases inhibitor; and 3) H(2)O(2)-induced cell death was increased in BMK1- and Src-knockdown RASMCs as well as in PP2-treated RASMCs. These findings suggested that Src and BMK1 may play defensive and resistive roles against oxidative stress-induced death in RASMCs.

Olmesartan inhibits angiotensin II-Induced migration of vascular smooth muscle cells through Src and mitogen-activated protein kinase pathways.

Clinical studies have shown that angiotensin-receptor blockers (ARBs) reduce the risk of cardiovascular diseases in hypertensive patients. It is assumed that the reduction of the risk by ARBs may be attributed in part to the inhibition of angiotensin II (AII)-induced vascular smooth muscle cell (VSMC) migration associated with atherosclerosis. However, the effect of ARBs on AII-induced changes in intracellular signaling and resultant cell migration has not been well established. Here, we investigated the effect of olmesartan, an ARB, on AII-induced extracellular signal-regulated kinases 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK) activation and rat aortic smooth muscle cell (RASMC) migration. Olmesartan inhibited AII-induced ERK1/2 and JNK activation at lower concentrations (10 nM). On the other hand, PP2, a Src tyrosine kinase inhibitor, also inhibited AII-induced ERK1/2 and JNK activation, but its effect on ERK1/2 was less pronounced than that of olmesartan. Olmesartan, U0126 (an ERK1/2 inhibitor), SP600125 (a JNK inhibitor), and PP2 potently inhibited AII-induced RASMC migration. From these findings, it was inferred that angiotensin-receptor blockade by olmesartan results in the inhibition of AII-induced activation of Src, ERK1/2, and JNK in RASMC. Olmesartan may be a potent inhibitor of AII-induced VSMC migration, which may be involved in the progression of atherosclerosis.

Neuroprotective effects of pramipexole against tunicamycin-induced cell death in PC12 cells.

1. Pramipexole (PPX), a dopamine D2 and D3 receptor agonist, exerts neuroprotective effects via both dopamine receptor-mediated and non-dopaminergic mechanisms. In the present study, we demonstrate that PPX reduces the toxicity of tunicamycin, a typical endoplasmic reticulum (ER) stressor, in PC12h cells, a subline of PC12 cells. 2. The PC12h cells were treated with 300 micromol / L PPX in the presence of 0.5 micromol / L tunicamycin for 24 h. The neuroprotective effects of PPX against tunicamycin-induced cell death were evaluated using 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) release assays, Hoechst 33258 staining and western blot analysis. 3. Tunicamycin (0.2, 0.3 and 0.5 microg / mL) dose-dependently decreased MTT activity and increased LDH release from PC12h cells. Treatment with 300 micromol / L PPX rescued the tunicamycin-induced decrease in cell viability. 4. Spiperone (10 micromol / L), a dopamine D2 and D4 receptor antagonist, had no effect on PPX neuroprotection against tunicamycin in these cells. Marker proteins of ER stress and apoptosis are known to be upregulated by tunicamycin, but we detected no significant effects of PPX on these factors. 5. In conclusion, we speculate that a combination of several mechanisms may be involved in PPX-induced neuroprotection.

Mouse equilibrative nucleoside transporter 2 (mENT2) transports nucleosides and purine nucleobases differing from human and rat ENT2.

Several mammalian nucleoside transporters have been identified at the molecular level. Human and rat equilibrative nucleoside transporter 2 (hENT2 and rENT2, respectively) was previously reported to have the dual ability of transporting both nucleosides and nucleobases. In the present study, we characterized the transport of a variety of nucleosides and nucleobases via recombinant mouse ENT2 (mENT2). Cloned mENT2 mediated the uptake of nucleosides and purine nucleobases, but not pyrimidine nucleobases. The mENT2-mediated uptake of adenosine was significantly inhibited by nucleosides and nucleobases, irrespective of purine and pyrimidine. The K(m) values for the uptake of nucleosides and purine nucleobases mediated by mENT2 varied between 1.24 and 16.3 microM, and the transport clearances of adenosine and hypoxanthine via the transporter were greater than those of other substrates. Therefore, we concluded that mENT2 is nucleoside and purine nucleobase transporter, and pyrimidine nucleobases are blockers for the transporter, differing from hENT2 and rENT2 that were reported to also transport pyrimidine nucleobases.