Oxidative Stress-Responsive Apoptosis Inducing Protein (ORAIP) Plays a Critical Role in Dextran Sulfate Sodium-Induced Murine Model of Ulcerative Colitis.

Oxidative stress is implicated in the pathogenesis of various acute disorders including ischemia/reperfusion injury, ultraviolet/radiation burn, as well as chronic disorders such as dyslipidemia, atherosclerosis, diabetes mellitus, chronic renal disease, and inflammatory bowel disease (IBD). However, the precise mechanism involved remains to be clarified. We formerly identified a novel apoptosis-inducing humoral protein, in a hypoxia/reoxygenation-conditioned medium of cardiac myocytes, which proved to be 69th tyrosine-sulfated eukaryotic translation initiation factor 5A (eIF5A). We named this novel tyrosine-sulfated secreted form of eIF5A Oxidative Stress-Responsive Apoptosis-Inducing Protein (ORAIP). To investigate the role of ORAIP in a dextran sulfate sodium (DSS)-induced murine model of ulcerative colitis (UC), we analyzed the effects of in vivo treatment with anti-ORAIP neutralizing monoclonal antibody (mAb) on the DSS-induced disease exacerbation. The body weight in anti-ORAIP mAb-treated group was significantly heavier than that in a mouse IgG-treated control group on day 8 of DSS-treatment ((85.21 ± 1.03%) vs. (77.38 ± 2.07%); (mean ± SE0, n = 5 each, p < 0.01, t-test). In vivo anti-ORAIP mAb-treatment also significantly suppressed the shortening of colon length as well as Disease Activity Index (DAI) score ((5.00 ± 0.44) vs. (8.20 ± 0.37); (mean ± SE), n = 5 each, p < 0.001, t-test) by suppressing inflammation of the rectal tissue and apoptosis of intestinal mucosal cells. These data reveal the pivotal role of ORAIP in DSS-induced oxidative stress involved in an animal model of UC.

Oxidative stress-responsive apoptosis inducing protein (ORAIP) plays a critical role in doxorubicin-induced apoptosis in rat cardiac myocytes.

BACKGROUND: Oxidative stress is implicated in the pathogenesis of doxorubicin-induced apoptosis in cardiac myocytes. However, the precise mechanism remains uncertain. We identified an apoptosis-inducing humoral factor, in a conditioned medium from cardiac myocytes subjected to hypoxia/reoxygenation, to be 69th tyrosine-sulfated eukaryotic translation initiation factor 5A (eIF5A). We named this novel secreted form of eIF5A, Oxidative stress-Responsive Apoptosis Inducing Protein (ORAIP). We confirmed that ischemia/reperfusion, ultraviolet-irradiation, and ionizing radiation significantly increased plasma levels of ORAIP in vivo, supporting that secretion of ORAIP is specific to the oxidative stress. To investigate the role of ORAIP in doxorubicin-induced apoptosis of cardiac myocytes. METHODS: We analyzed plasma levels of ORAIP in rats treated with doxorubicin (10 mg/Kg) in vivo, and the effects of neutralizing anti-ORAIP monoclonal antibody (mAb) on doxorubicin-induced apoptosis of cardiac myocytes in vitro. RESULTS: The (mean ± SE) plasma ORAIP levels before doxorubicin administration were (13.7 ± 2.7) ng/mL, they markedly increased with peak levels ([178.6 ± 6.5] ng/mL, p < 0.00001, vs. before administration) at 20 to 60 min after doxorubicin administration, then gradually decreased to (118.0 ± 4.8) ng/mL at 120 min. Treatment with a neutralizing anti-ORAIP mAb significantly (nearly 50%) suppressed doxorubicin-induced apoptosis of cardiac myocytes. CONCLUSIONS: These data indicate that doxorubicin induces oxidative stress resulting in the strong expression of ORAIP in cardiac myocytes and marked secretion of ORAIP into peripheral circulation. This strongly suggests that ORAIP can be a novel sensitive biomarker as well as a possible therapeutic target for doxorubicin-induced cell injury in anti-cancer therapy.

Oxidative stress-responsive apoptosis-inducing protein in patients with heterozygous familial hypercholesterolemia.

Oxidative stress, an inducer of apoptosis, plays a critical role in ischemia/reperfusion injury and atherosclerosis. We previously identified an apoptosis-inducing ligand, the post-translationally modified secreted form of eukaryotic translation initiation factor 5A (eIF5A), 'oxidative stress-responsive apoptosis-inducing protein' (ORAIP). In this study, we investigated the role of ORAIP in patients with heterozygous familial hypercholesterolemia (HeFH), a leading cause of premature cardiovascular disease. We analyzed plasma ORAIP and oxidized low-density lipoprotein (oxLDL) levels in 60 patients with HeFH (60% male, 57.0 ± 13.6 years of age) and 20 patients with LDL-C hypercholesterolemia (DL, 85% male, 64.1 ± 13.3 years of age). The coronary artery atherosclerosis from the patients with HeFH who had a coronary artery bypass graft was investigated by double immunostaining. The plasma ORAIP levels in the patients with HeFH were significantly elevated compared to those in the patients with DL (73.5 ± 46.0 vs. 48.3 ± 21.4 ng/mL, p = 0.0277). The plasma oxLDL levels in HeFH patients were also elevated (156.8 ± 65.2 vs. 123.7 ± 46.6 mg/dL, p = 0.0461) compared to those in DL patients and correlated with maxLDL-C levels (R = 0.4454, p = 0.00648). Double-immunostaining of ORAIP and oxLDL in the coronary artery from patients with HeFH who had a coronary artery bypass graft showed that ORAIP and oxLDL were colocalized with apoptotic vascular smooth muscle cells in the atherosclerotic plaque. ORAIP plays a role in the development of oxidative stress-induced atherosclerosis and may be an important therapeutic target for plaque rupture in patients with HeFH.

Oxidative stress-responsive apoptosis inducing protein (ORAIP) plays a critical role in cerebral ischemia/reperfusion injury.

Oxidative stress is known to play a critical role in the pathogenesis of various disorders, especially in ischemia/reperfusion (I/R) injury. We identified an apoptosis-inducing humoral factor and named this novel post translationally modified secreted form of eukaryotic translation initiation factor 5A (eIF5A) "oxidative stress-responsive apoptosis inducing protein" (ORAIP). The purpose of this study was to investigate the role of ORAIP in the mechanisms of cerebral I/R injury. Hypoxia/reoxygenation induced expression of ORAIP in cultured rat cerebral neurons, resulting in extensive apoptosis of these cells, which was largely suppressed by neutralizing anti-ORAIP monoclonal antibody (mAb) in vitro. Recombinant-ORAIP induced extensive apoptosis of cerebral neurons. Cerebral I/R induced expression of ORAIP in many neurons in a rat tandem occlusion model in vivo. In addition, we analyzed the effects of intracerebroventricular administration of neutralizing anti-ORAIP mAb on the development of cerebral infarction. Cerebral I/R significantly increased ORAIP levels in cerebrospinal fluid. Treatment with intracerebroventricular administration of neutralizing anti-ORAIP mAb reduced infarct volume by 72%, and by 55% even when started after reperfusion. These data strongly suggest that ORAIP plays a pivotal role and will offer a critical therapeutic target for cerebral I/R injury induced by thrombolysis and thrombectomy for acute ischemic stroke.

Elevation of the vitreous body concentrations of oxidative stress-responsive apoptosis-inducing protein (ORAIP) in proliferative diabetic retinopathy.

PURPOSE: Oxidative stress has been implicated in the pathogenesis of various disorders, including diabetic retinopathy (DR). Oxidative stress-responsive apoptosis-inducing protein (ORAIP; a tyrosine-sulfated secreted form of eukaryotic translation initiation factor 5A [eIF5A]) is a recently discovered pro-apoptotic ligand that is secreted from cells in response to oxidative stress and induces apoptosis in an autocrine fashion. This study aimed to determine if ORAIP plays a role in DR. METHODS: To investigate the role of ORAIP in DR, we analyzed the levels of ORAIP in the vitreous body and their relationship with the extent of proliferative diabetic retinopathy (PDR). Enzyme-linked immunosorbent assay was used to quantify the levels of ORAIP, vascular endothelial growth factor (VEGF), C-C motif chemokine ligand 2 (CCL2), interleukin-6 (IL-6), and IL-8 in the vitreous body of 40 eyes from 28 patients with PDR and 11 patients with non-PDR (NPDR). We also analyzed the expression of ORAIP in insoluble proliferative tissues from vitreous body samples by immunofluorescent staining. RESULTS: The vitreous body concentration of ORAIP was significantly (P = 0.0433) higher in the PDR group (52.26 ± 8.68 [mean ± SE] ng/mL, n = 29) than in the NPDR group (28.21 ± 7.30 ng/mL, n = 11). However, there were no significant correlations between the concentration of ORAIP and those of VEGF, IL-6, CCL2, or IL-8. ORAIP expression was observed in the insoluble proliferative tissues in vitreous body samples of most patients in the PDR group, whereas almost no expression of ORAIP was observed in patients in the NPDR group. CONCLUSIONS: Our findings strongly suggest that ORAIP plays a role in oxidative stress-induced retinal injury and may be a sensitive diagnostic marker and a promising therapeutic target for oxidative stress-induced cytotoxicity.

Oxidative Stress-Responsive Apoptosis Inducing Protein (ORAIP) Plays a Critical Role in High Glucose-Induced Apoptosis in Rat Cardiac Myocytes and Murine Pancreatic ß-Cells.

We previously identified a novel apoptosis-inducing humoral factor in the conditioned medium of hypoxic/reoxygenated-cardiac myocytes. We named this novel post-translationally-modified secreted-form of eukaryotic translation initiation factor 5A Oxidative stress-Responsive Apoptosis-Inducing Protein (ORAIP). We confirmed that myocardial ischemia/reperfusion markedly increased plasma ORAIP levels and rat myocardial ischemia/reperfusion injury was clearly suppressed by neutralizing anti-ORAIP monoclonal antibodies (mAbs) in vivo. In this study, to investigate the mechanism of cell injury of cardiac myocytes and pancreatic ß-cells involved in diabetes mellitus (DM), we analyzed plasma ORAIP levels in DM model rats and the role of ORAIP in high glucose-induced apoptosis of cardiac myocytes in vitro. We also examined whether recombinant-ORAIP induces apoptosis in pancreatic ß-cells. Plasma ORAIP levels in DM rats during diabetic phase were about 18 times elevated as compared with non-diabetic phase. High glucose induced massive apoptosis in cardiac myocytes (66.2 ± 2.2%), which was 78% suppressed by neutralizing anti-ORAIP mAb in vitro. Furthermore, recombinant-ORAIP clearly induced apoptosis in pancreatic ß-cells in vitro. These findings strongly suggested that ORAIP plays a pivotal role in hyperglycemia-induced myocardial injury and pancreatic ß-cell injury in DM. ORAIP will be a biomarker and a critical therapeutic target for cardiac injury and progression of DM itself.

Plasma levels of oxidative stress-responsive apoptosis inducing protein (ORAIP) in rats subjected to physicochemical oxidative stresses.

Oxidative stress is known to play a pivotal role in the pathogenesis of various disorders including atherosclerosis, aging and especially ischaemia/reperfusion injury. It causes cell damage that leads to apoptosis. However, the precise mechanism has been uncertain. Recently, we identified an apoptosis-inducing humoral factor in a hypoxia/reoxygenated medium of cardiac myocytes. We named this novel post-translationally modified secreted form of eukaryotic translation initiation factor 5A (eIF5A) as oxidative stress-responsive apoptosis inducing protein (ORAIP). We developed a sandwich ELISA and confirmed that myocardial ischaemia/reperfusion markedly increased plasma levels of ORAIP. To investigate whether the role of ORAIP is common to various types of oxidative stress, we measured plasma ORAIP levels in rats subjected to three physicochemical models of oxidative stress including N2/O2 inhalation, cold/warm-stress (heat shock) and blood acidification. In all three models, plasma ORAIP levels significantly increased and reached a peak level at 10-30 min after stimulation, then decreased within 60 min. The (mean±S.E.M.) plasma ORAIP levels before and after (peak) stimulation were (16.4±9.6) and (55.2±34.2) ng/ml in N2/O2 inhalation, (14.1±12.4) and (34.3±14.6) ng/ml in cold/warm-stress, and (18.9±14.3) and (134.0±67.2) ng/ml in blood acidification study. These data strongly suggest that secretion of ORAIP in response to oxidative stress is universal mechanism and plays an essential role. ORAIP will be an important novel biomarker as well as a specific therapeutic target of these oxidative stress-induced cell injuries.

Secreted tyrosine sulfated-eIF5A mediates oxidative stress-induced apoptosis.

Oxidative stress plays a critical role in ischemia/reperfusion-injury, atherosclerosis, and aging. It causes cell damage that leads to apoptosis via uncertain mechanisms. Because conditioned medium from cardiac myocytes subjected to hypoxia/reoxygenation induces extensive apoptosis of cardiac myocytes under normoxia, we hypothesized that a humoral factor released from the hypoxic/reoxygenated cardiac myocytes mediates apoptosis. We identified an apoptosis-inducing humoral factor in the hypoxia/reoxygenation-conditioned medium. Here, we found that eIF5A undergoes tyrosine sulfation in the trans-Golgi and is rapidly secreted from cardiac myocytes in response to hypoxia/reoxygenation; then, eIF5A induces apoptosis by acting as a pro-apoptotic ligand. The apoptosis of cardiac myocytes induced by hypoxia/reoxygenation or ultraviolet irradiation was suppressed by anti-eIF5A neutralizing monoclonal antibodies (mAbs) in vitro. Myocardial ischemia/reperfusion (but not ischemia alone) markedly increased the plasma levels of eIF5A, and treatment with anti-eIF5A neutralizing mAbs significantly reduced myocardial injury. These results identify an important, novel specific biomarker and a critical therapeutic target for oxidative stress-induced cell injury.

A Case of Takayasu's Arteritis with Total Occlusion of the Abdominal Aorta Treated Only with Oral Medication for More Than 40 Years.

Takayasu's arteritis affects most commonly young women, often causing stenotic and occasionally dilated lesions of the medium-to-large-sized arteries with an acute inflammatory signs and symptoms. Here, we report a rare case of Takayasu's arteritis with total occlusion of the abdominal aorta, which was successfully treated with medication alone and asymptomatic over 40 years. Magnetic resonance imaging revealed total occlusion of the abdominal aorta and stenosis of the right carotid artery. This is the first report of a very rare case of Takayasu's arteritis, in which medical treatment only was successful against total occlusion of the abdominal aorta.

Basal cardiomyopathy develops in rabbits with ventricular tachyarrhythmias induced by a single injection of adrenaline.

We have recently demonstrated that basal cardiomyopathy develops in rabbits with ventricular tachyarrhythmias that have been induced by electrical stimulation of the cervical vagus. This study investigated whether similar basal cardiomyopathy would develop in rabbits with ventricular tachyarrhythmias induced by a single injection of adrenaline. Adrenaline was intravenously infused for 10-360 seconds in anesthetized rabbits. Colloidal carbon was injected after adrenaline infusion. Wall movement velocity of the left ventricular base was assessed by tissue Doppler echocardiography. Animals were killed either 1 week or 3-4 weeks later. Pathological lesions were identified by deposits of carbon particles. Animals were divided into two groups according to the infused dose of adrenaline. The small-dose group (group S, n = 15) received 1-10 µg and the large-dose group (group L, n = 23) received 15-60 µg of adrenaline. Adrenaline infusion induced premature ventricular contractions followed by monomorphic ventricular tachycardias in 22 of 23 animals in group L, but in only 1 of 15 animals in group S. Wall movement velocity of the left ventricular base decreased just after adrenaline infusion, remained low after 1 week, and recovered to near-baseline levels after 3-4 weeks in group L. Unique cardiac lesions identified by deposits of carbon particles were frequently observed on the left ventricular basal portion, almost always associated with the mitral valve and papillary muscles, but were never observed in the apical area. Lesions involving all areas of the left ventricular basal portion were observed in 22 of 23 animals in group L, but in only 2 of 15 animals in group S. Basal cardiomyopathy developed in rabbits with ventricular tachycardias induced by a single injection of adrenaline.

[An elderly woman with macrocytic anemia and acute high-output heart failure following acute bleeding due to a gastric ulcer].

Although macrocytic anemia can develop in patients with acute blood loss, such anemia in very old patients is uncommon. In this report, we describe the course of an 89-year-old woman who had a rapid recovery from macrocytic anemia by medication only after acute blood loss due to a gastric ulcer. She had been treated with antihypertensive drugs for the previous 28 years at our outpatient clinic, and was admitted because of acute anemia 6 days after she had experienced tarry stool. Her hemoglobin (Hb) count and mean corpuscular volume (MCV) were 8.4 g/dl, and 103 fl, respectively. A gastroscopic examination indicated that the tarry stool originated from a fresh gastric ulcer. She was treated with an iron preparation, a diuretic and a proton pump inhibitor. The anemia was rapidly improved to Hb 10.5 g/dl and MCV 106 fl in one week, and to Hb 14.5 g/dl and MCV 99 fl in 4 weeks. At admission, she had slight pleural effusion and slight edema associated with an increase in her plasma brain natriuretic peptide (BNP) level (323 pg/ml), and her left ventricular ejection fraction was 76% based on the echocardiography findings, which are signs of the high-output heart failure without remarkable left ventricular diastolic dysfunction (E/e': 11.2). However, these signs improved rapidly, and her BNP level thereafter decreased to 114 pg/ml within four weeks.

Ventricular tachyarrhythmia-related basal cardiomyopathy in rabbits with vagal stimulation--a novel experimental model for inverted Takotsubo-like cardiomyopathy.

BACKGROUND: Electrical stimulation of the intact (unsectioned) cervical vagus in rabbits frequently provokes ventricular tachyarrhythmias that are often accompanied by mitral regurgitation. Unique pathological lesions often arise on the mitral valve, papillary muscles, and mitral annulus (mitral complex), the latter two of which become swollen and stiffened. These lesions are reversible in nature. Previous studies have essentially ignored the basal portion except for the mitral annulus. Therefore, the present study examined pathological lesions on the left ventricular basal portion in rabbits. METHODS: The intact right vagal nerves of 20 anesthetized rabbits were repeatedly electrically stimulated under electrocardiographic monitoring. Colloidal carbon (lml) was injected intravenously immediately after the end of the stimulation and all animals were killed 1 week later. Pathological lesions were identified as carbon deposits visible at gross examination. RESULTS: Ventricular bigeminy was induced after vagal stimulation in 15 (75%) of the 20 rabbits. Pathological lesions were evident on the basal portion in 16 (80%) and on the mitral valve and papillary muscles of 15 (75%) of the 20 rabbits. Ventricular bigeminy was closely associated with the development of the pathological lesions, which were rarely observed on the ventricular apex. CONCLUSION: Cardiomyopathic lesions involving the basal portion and mitral complex were frequently induced in rabbits by vagal stimulation. These lesions bear a close similarity in distribution and reversibility to inverted Takotsubo cardiomyopathy.

A critical link between Toll-like receptor 3 and type II interferon signaling pathways in antiviral innate immunity.

A conundrum of innate antiviral immunity is how nucleic acid-sensing Toll-like receptors (TLRs) and RIG-I/MDA5 receptors cooperate during virus infection. The conventional wisdom has been that the activation of these receptor pathways evokes type I IFN (IFN) responses. Here, we provide evidence for a critical role of a Toll-like receptor 3 (TLR3)-dependent type II IFN signaling pathway in antiviral innate immune response against Coxsackievirus group B serotype 3 (CVB3), a member of the positive-stranded RNA virus family picornaviridae and most prevalent virus associated with chronic dilated cardiomyopathy. TLR3-deficient mice show a vulnerability to CVB3, accompanied by acute myocarditis, whereas transgenic expression of TLR3 endows even type I IFN signal-deficient mice resistance to CVB3 and other types of viruses, provided that type II IFN signaling remains intact. Taken together, our results indicate a critical cooperation of the RIG-I/MDA5-type I IFN and the TLR3-type II IFN signaling axes for efficient innate antiviral immune responses.

Gamma-delta T-cell-mediated dilated cardiomyopathy.

Gamma-delta T-cells are usually minor component of peripheral blood and lymphoid tissues, but may play an important role in autoimmune diseases. We here describe the first case of dilated cardiomyopathy (DCM) with heart infiltration by mostly gamma-delta T-cells, who improved significantly by steroid therapy. In general, steroid therapy has only a little effect on DCM, however these findings might have implications with respect to the selection of patients who might respond to immunosuppressive therapy.

A case of neonatal lupus erythematosus presenting delayed dilated cardiomyopathy with circulating autoantibody to annexin A6.

Patients with neonatal lupus erythematosus (NLE) often have congenital heart block with or without heart failure and are born to mothers who have anti-SS-A and/or anti-SS-B antibodies. NLE has been considered to result from the placental transmission of maternal autoantibodies into the fetal circulation causing myocardial damage. We report a case of NLE with congenital heart block who had undergone pacemaker implantation at the age of 17, and then developed dilated cardiomyopathy (DCM) at the age of 19, which is much later than in most other cases. The patient's mother was positive for anti-SS-A and anti-SS-B antibodies, whereas the patient was negative for both anti-SS-A and anti-SS-B antibodies. There were some autoantibodies against cell surface antigens of cardiac myocytes in the serum from the patient, and annexin A6 was identified as one of the autoantigens. This is the first report demonstrating that annexin A6 is involved in the myocardial injury in patients with NLE. The results indicate that inhibition of annexin A6 function may prevent autoantibody-mediated myocardial injury in at least some cases of DCM.

Roles of programmed death-1 (PD-1)/PD-1 ligands pathway in the development of murine acute myocarditis caused by coxsackievirus B3.

OBJECTIVE: This study was designed to investigate the roles of programmed death-1 (PD-1) and PD-1 ligands (PD-L) in the development of murine acute myocarditis caused by Coxsackievirus B3. PD-1/PD-L belong to the CD28/B7 superfamily, and the PD-1/PD-L pathway is known to transduce a negative immunoregulatory signal that antagonizes the T-cell receptor-CD28 signal and inhibits T-cell activation. METHODS: We first analyzed the expression of PD-L1/PD-L2 on cardiac myocytes in vivo and in vitro. Second, we examined the effects of in vivo treatment with an anti-PD-1, PD-L1, or PD-L2 monoclonal antibodies on the development of myocardial inflammation in C3H/He mice infected with Coxsackievirus B3. Third, to investigate the effects of anti-PD-1 monoclonal antibody treatment on the activation of the infiltrating cells, we examined the expression of interleukin (IL)-2, interferon (IFN)-gamma, CD40 ligand (CD40L), Fas ligand (FasL), and perforin as activation markers in mouse hearts by a semiquantitative PCR method. RESULTS: PD-L1 was markedly induced on cardiac myocytes with acute myocarditis. In vivo anti-PD-1 or -PD-L1 blocking monoclonal antibody treatment increased the myocardial inflammation whereas anti-PD-1 stimulating monoclonal antibody treatment decreased the myocardial inflammation, and anti-PD-L2 monoclonal antibody treatment had no effect. Anti-PD-1 monoclonal antibody treatment significantly increased the expression of IFN-gamma, FasL, CD40L, perforin, and Coxsackievirus B3 genomes in myocardial tissue. CONCLUSION: Our findings strongly suggest that the PD-1/PD-L1 pathway played a pivotal role in suppressing myocardial inflammation and raise the possibility of immunotherapy by stimulating the PD-1/PD-L1 pathway to prevent myocardial damage in viral myocarditis.

Giant cell and Takayasu arteritis.

PURPOSE OF REVIEW: Giant cell arteritis and Takayasu arteritis are well known large vessel vasculitides with an unknown etiology. As they have similar clinical features, this short article reviews recent advances in clinical and pathophysiological findings, focusing in particular on papers published in the past year. RECENT FINDINGS: Delayed gadolinium-enhanced magnetic resonance imaging showed delayed hyperenhancement in the aortic wall in Takayasu arteritis. This technique may be useful in monitoring disease activity or inflammation in the arterial wall and can be used for small vessels such as temporal arteries in giant cell arteritis with high-resolution imaging. Evidence is accumulating that antitumor necrosis factor-alpha monoclonal antibody therapy can be useful for patients refractory to corticosteroid and/or immunosuppressant treatment. Functional promoter polymorphisms of genes encoding inducible nitric oxide synthase and I-kappaB-like protein were suggested to be associated with susceptibility to giant cell arteritis and Takayasu arteritis, respectively. SUMMARY: Advances in imaging technique will make it possible to evaluate inflammatory activity of the vascular lesions and provide a useful guide for treatment of giant cell arteritis and Takayasu arteritis. Further understanding of the pathophysiological mechanism may contribute to the development of new medicine targeting critical factors in the pathogenesis, such as antitumor necrosis factor-alpha agents.