Characteristics of and risk factors for interstitial lung disease induced by chemotherapy for lung cancer.

BACKGROUND: Drug-induced interstitial lung disease (DILD) is generally a serious adverse effect and almost always necessitates the discontinuation of the offending drug. Cancer pharmacotherapy is strongly associated with DILD, and the risk of DILD has been suggested to be higher in patients with lung cancer because of preexisting pneumonic disease. OBJECTIVE: The aim of this retrospective study was to identify the risk factors and prognostic factors for early death from interstitial lung disease (ILD) induced by chemotherapy for lung cancer. METHODS: The medical records of 459 patients who underwent chemotherapy for lung cancer between April 2007 and March 2013 were analyzed with regard to patient background and DILD development, initial symptoms, and prognosis. RESULTS: A total of 33 patients (7.2%) developed chemotherapy-induced ILD. The most frequently observed initial symptom was dyspnea (94.3%). Preexisting ILD was identified as a risk factor for DILD (odds ratio [OR] = 5.38; 95% CI = 2.47-11.73; P < 0.01). Among the 33 patients who developed DILD, 10 patients suffered an early death despite steroid therapy. Poor prognostic factors included epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) use (OR = 9.26; 95% CI = 1.05-82.0; P < 0.05) and 2 or more prior chemotherapy regimens (OR = 6.95; 95% CI = 1.14-42.3; P < 0.05). CONCLUSIONS: Many lung cancer patients have coexisting ILD, and these patients have a high risk of developing chemotherapy-induced ILD. In addition, patients with DILD who underwent EGFR-TKI therapy and 2 or more prior chemotherapy regimens had a higher risk of fatal outcome.

Spontaneously hyperactive MEK-Erk pathway mediates paradoxical facilitation of cell proliferation in mild hypoxia.

BACKGROUND: Oxygen is important for common eukaryotic cells to generate ATP. Pathophysiological conditions such as ischemic diseases cause tissue hypoxia. In addition, oxygen availability in deep tissues is supposed to be far lower than surrounding atmosphere even in healthy animals, and the oxygen partial pressures in most normal tissues are estimated to be around 40-50mmHg, so-called mild hypoxia. Recent studies have demonstrated that mild hypoxia has distinct effects on living cells from severe hypoxia. For instance, mild hypoxia was reported to promote cell reprogramming. Although severe hypoxia is known to inhibit cell proliferation, mild hypoxia has been paradoxically demonstrated to increase cell proliferation. However, it has not been clarified by which molecular mechanisms mild hypoxia evokes the discontinuous increment of cell proliferation. METHODS: We established experimental conditions showing the opposite influences of mild and severe hypoxia on cell proliferation using undifferentiated Caco2 human colon carcinoma cells in order to clarify the underlying molecular mechanism. RESULTS: The basal activity of Erk, which is a typical mediator of mitogenic signals, is spontaneously increased specifically in cells exposed to mild hypoxia, and inhibition of MEK, an upstream kinase of the Erk, completely inhibited the mild hypoxia-induced enhancement of cell proliferation. CONCLUSIONS: Spontaneous hyperactivation of the MEK-Erk pathway by mild hypoxia should be the plausible molecular mechanism of the paradoxical promotion of cell proliferation. GENERAL SIGNIFICANCE: Our findings will provide clues to the molecular basis of mild hypoxia-evoked phenomena such as cell reprogramming.

Effect of ghrelin on autonomic activity in healthy volunteers.

Ghrelin is a novel growth hormone (GH)-releasing peptide originally isolated from the stomach. Recently, we have shown that ghrelin suppresses cardiac sympathetic activity and prevents early left ventricular remodeling in rats with myocardial infarction. In the present study, we evaluated the effect of ghrelin on autonomic nerve activity in healthy human subjects. An intravenous bolus of human synthetic ghrelin (10µg/kg) was administered to 10 healthy men (mean age, 33 years). Holter monitoring assessment was performed before and during 2h after the ghrelin therapy. The standard deviation of normal RR intervals (SDNN), square root of the mean of the sum of the squares of differences between adjacent RR intervals (rMSSD), high-frequency power (HF), and low-frequency power (LF) were analyzed. Blood samples were also obtained before and after the therapy. A single administration of ghrelin decreased both heart rate and blood pressure. Interestingly, ghrelin significantly decreased the LF and LF/HF ratio of heart rate variability and increased the SDNN, rMSSD, and HF. Ghrelin also elicited a marked increase in circulating GH, but not insulin-like growth factor-1. These data suggest that ghrelin might suppress cardiac sympathetic nerve activity and stimulate cardiac parasympathetic nerve activity.

Risk Factors for Early-Onset Peripheral Neuropathy Caused by Vincristine in Patients With a First Administration of R-CHOP or R-CHOP-Like Chemotherapy.

BACKGROUND: Peripheral neuropathy is a well-known side effect of vincristine (VCR), a microtubule inhibitor used for R-CHOP or R-CHOP-like (namely R-CVP and R-THP-COP) regimens. Previous studies have shown that both the total dose of VCR and the number of treatment cycles are related to the incidence of VCR-induced peripheral neuropathy (VIPN). However, VIPN will also occur during the first treatment cycle regardless of the total dose of VCR or number of treatment cycles (early-onset VIPN). There is little information about early-onset VIPN, and it is difficult to predict. The present study's goal was to identify risk factors for early-onset VIPN. METHODS: We analyzed the case records of patients who had their first administration of an R-CHOP or R-CHOP-like regimen between April 2008 and August 2013 at Tokushima University Hospital in Tokushima, Japan. To identify the risk factors for early-onset VIPN, we performed univariate and multivariate logistic regression analyses. RESULTS: Forty-one patients underwent an R-CHOP or R-CHOP-like regimen for the first time at Tokushima University Hospital between April 2008 and August 2013, and 14 patients had grade 1 or higher early-onset VIPN. A univariate analysis revealed that age, the dose of VCR and the concomitant use of aprepitant appeared to be the risk factors of early-onset VIPN. In our calculation using receiver-operator characteristics curves, the cut-off value for patient age was 65 years and that of the dose of VCR was 1.9 mg. A multivariate analysis revealed that VCR dose ≥ 1.9 mg and the concomitant use of the antiemetic aprepitant were independent risk factors for early-onset VIPN. CONCLUSIONS: Our present study showed that the patients who had VCR dose ≥ 1.9 mg and the concomitant use of aprepitant had the risk for early-onset VIPN. This suggests that it is important to use aprepitant in light of the risk of early-onset VIPN and the benefit of aprepitant's antiemetic effect in R-CHOP and R-CHOP-like regimens.

Serious adverse events and compensation in registration trials: a review of data from a Japanese university hospital.

BACKGROUND: Clinical trials leading to regulatory approval, or registration trials, play a central role in the development of drugs and medical devices. The contribution of support staff, such as the clinical research coordinator (CRC) and administrative officers, in registration trials is now widely recognized. Attending to serious adverse events is an important duty of the CRC and investigators alike, and managing these complications and compensation constitutes a key responsibility. We retrospectively examined the frequency of serious adverse events and compensation events reported from 2007 through 2011 at Tokushima University Hospital, an academic hospital in rural Japan. We present herein the results of our analysis. RESULTS: Over the five-year period, 284 subjects participating in 106 registration trials experienced a total of 43 serious adverse events, and eight compensation events were documented. Among the serious adverse events, 35 (81.4%) were considered not related to the investigational drug, and 17 (39.5%) resulted in withdrawal of the study drug. Patients with malignant diseases experienced serious adverse events significantly more frequently compared to those with non-malignant diseases (28.3% versus 8.2%, respectively; P < 0.01). CONCLUSIONS: The CRC should be vigilant for serious adverse events in oncology clinical trials due to the generally higher frequency of these complications in subjects with malignancy. However, on an individual basis, the CRC may be seldom involved in the process for compensating serious adverse events. Therefore, the CRC's ability to share such experiences may serve as an opportunity for educating clinical trial support staff at the study site as well as those at other sites. However, further study is warranted to determine the role of the clinical trial support staff in optimizing methods for managing adverse events requiring compensation in registration trials.

Identification of the risk factors associated with hypocalcemia induced by denosumab.

Denosumab, a fully human monoclonal antibody that inhibits the receptor activator of nuclear factor-κB ligand, inhibits the activation of osteoclasts. Some clinical trials have shown that denosumab suppresses bone resorption in patients with advanced cancer, but hypocalcemia has been reported as a serious adverse effect after the administration of denosumab. It is difficult to predict hypocalcemia in such cases because the risk factors for denosumab-induced hypocalcemia have not been reported. Accordingly, the aim of the present study was to identify the risk factors for hypocalcemia induced by denosumab. We retrospectively reviewed the records of patients who had received denosumab at Tokushima University Hospital between April 2012 and May 2013. Fifty-three patients were analyzed and eleven patients had hypocalcemia after administration of denosumab. Univariate logistic regression analysis revealed that the patients who had not been administered zoledronic acid before receiving denosumab or had lower creatinine clearance (CCr) appeared to have a higher risk of hypocalcemia (p<0.05). The cut off value of CCr was 50.4 mL/min calculated by receiver-operator characteristics curves. Moreover, multivariate logistic regression analysis revealed that non-administration of zoledronic acid (odds ratio 10.43, p<0.05) and CCr less than 50.0 mL/min (odds ratio 5.90, p<0.05) were independent risk factors for denosumab-induced hypocalcemia. These findings provide useful information regarding the monitoring of hypocalcemia in patients receiving denosumab.

A novel targeting therapy of malignant mesothelioma using anti-podoplanin antibody.

Podoplanin (Aggrus), which is a type I transmembrane sialomucin-like glycoprotein, is highly expressed in malignant pleural mesothelioma (MPM). We previously reported the generation of a rat anti-human podoplanin Ab, NZ-1, which inhibited podoplanin-induced platelet aggregation and hematogenous metastasis. In this study, we examined the antitumor effector functions of NZ-1 and NZ-8, a novel rat-human chimeric Ab generated from NZ-1 including Ab-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity against MPM in vitro and in vivo. Immunostaining with NZ-1 showed the expression of podoplanin in 73% (11 out of 15) of MPM cell lines and 92% (33 out of 36) of malignant mesothelioma tissues. NZ-1 could induce potent ADCC against podoplanin-positive MPM cells mediated by rat NK (CD161a(+)) cells, but not murine splenocytes or human mononuclear cells. Treatment with NZ-1 significantly reduced the growth of s.c. established tumors of MPM cells (ACC-MESO-4 or podoplanin-transfected MSTO-211H) in SCID mice, only when NZ-1 was administered with rat NK cells. In in vivo imaging, NZ-1 efficiently accumulated to xenograft of MPM, and its accumulation continued for 3 wk after systemic administration. Furthermore, NZ-8 preferentially recognized podoplanin expressing in MPM, but not in normal tissues. NZ-8 could induce higher ADCC mediated by human NK cells and complement-dependent cytotoxicity as compared with NZ-1. Treatment with NZ-8 and human NK cells significantly inhibited the growth of MPM cells in vivo. These results strongly suggest that targeting therapy to podoplanin with therapeutic Abs (i.e., NZ-8) derived from NZ-1 might be useful as a novel immunotherapy against MPM.

Nitrosonifedipine ameliorates angiotensin II-induced vascular remodeling via antioxidative effects.

Nifedipine is unstable under light and decomposes to a stable nitroso analog, nitrosonifedipine (NO-NIF). The ability of NO-NIF to block calcium channels is quite weak compared with that of nifedipine. Recently, we have demonstrated that NO-NIF reacts with unsaturated fatty acid leading to generate NO-NIF radical, which acquires radical scavenging activity. However, the effects of NO-NIF on the pathogenesis related with oxidative stress, such as atherosclerosis and hypertension, are unclear. In this study, we investigated the effects of NO-NIF on angiotensin II (Ang II)-induced vascular remodeling. Ang II-induced thickening and fibrosis of aorta were inhibited by NO-NIF in mice. NO-NIF decreased reactive oxygen species (ROS) in the aorta and urinary 8-hydroxy-20-deoxyguanosine. Ang II-stimulated mRNA expressions of p22(phox), CD68, F4/80, monocyte chemoattractant protein-1, and collagen I in the aorta were inhibited by NO-NIF. Moreover, NO-NIF inhibited Ang II-induced cell migration and proliferation of vascular smooth muscle cells (VSMCs). NO-NIF reduced Ang II-induced ROS to the control level detected by dihydroethidium staining and lucigenin chemiluminescence assay in VSMCs. NO-NIF suppressed phosphorylations of Akt and epidermal growth factor receptor induced by Ang II. However, NO-NIF had no effects on intracellular Ca(2+) increase and protein kinase C-δ phosphorylation induced by Ang II in VSMCs. The electron paramagnetic resonance spectra indicated the continuous generation of NO-NIF radical of reaction with cultured VSMCs. These findings suggest that NO-NIF improves Ang II-induced vascular remodeling via the attenuation of oxidative stress.

Plasma dipeptidyl peptidase 4 activity correlates with body mass index and the plasma adiponectin concentration in healthy young people.

We previously found that plasma dipeptidyl peptidase 4 (DPP4) activity was associated with the development of obesity, type 2 diabetes, and type 1 diabetes using animal models. In this study, we investigated whether DPP4 activity is correlated with the clinical parameters of obesity and/or diabetes in healthy young subjects. Body mass index (BMI), plasma DPP4 activity, total cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides, fasting blood glucose, adiponectin concentration, and body fat were measured in 165 subjects (110 males and 55 females, age 23.2 ± 2.4 years). In correlation analyses, DPP4 activity displayed strong positive correlations with BMI (p = 5.5 × 10(-5)) and total cholesterol (p = 0.0014), and a negative correlation with the plasma adiponectin concentration (p = 0.013), but not fasting blood glucose. Our findings suggest that plasma DPP4 activity is correlated with the clinical parameters of obesity rather than diabetes in young people.

Simvastatin represses translocation of Pseudomonas aeruginosa across Madin-Darby canine kidney cell monolayers.

Pseudomonas aeruginosa causes both invasive (bacteremic) and chronic noninvasive infections. An increase in intestinal epithelial permeability is a characteristic of severe sepsis. Alterations in the normal barrier function of the gut mucosa may result in the translocation of microbial cells and products. On the otherhand, it has been demonstrated that statin use is associated with a lower risk of mortality from bloodstream infections. Therefore, we investigated the ability of P. aeruginosa PAO1 to translocate across the Madin-Darby canine kidney (MDCK) cell monolayers in the presence and absence of simvastatin. The bacteria readily translocated across MDCK cell monolayers after 3 h of infection irrespective of the presence or absence of the drug in the medium. However, the bacteria were less able to penetrate the MDCK monolayers in the presence of simvastatin than in its absence. A gentamicin survival assay demonstrated that simvastatin did not affect the bacteria's invasive behavior in the MDCK cells.

Iron reduction by deferoxamine leads to amelioration of adiposity via the regulation of oxidative stress and inflammation in obese and type 2 diabetes KKAy mice.

Iron is an essential trace metal for most organisms. However, excess iron causes oxidative stress through production of highly toxic hydroxyl radicals via the Fenton/Haber-Weiss reaction. Iron storage in the body is reported to be associated with fat accumulation and type 2 diabetes mellitus. We investigated the role of iron in adiposity by using KKAy mice and obese and diabetic model mice. Eight-week-old KKAy mice were divided into two groups and treated with deferoxamine (DFO), an iron chelator agent, or a vehicle for 2 wk. DFO treatment diminished fat iron concentration and serum ferritin levels in KKAy mice. Fat weight and adipocyte size were reduced significantly in DFO-treated mice compared with vehicle-treated mice. Macrophage infiltration into fat was also decreased in DFO-treated mice compared with vehicle-treated mice. Superoxide production and NADPH oxidase activity in fat, as well as urinary 8-hydroxy-2'-deoxyguanosine excretion, were decreased in KKAy mice after DFO treatment while p22(phox) expression in adipose tissue was diminished in such mice. Ferritin expression in the fat of DFO-treated KKAy mice was decreased. In addition, F4/80-positive cells also presented through both p22(phox) and ferritin expression. The mRNA expression levels of inflammatory cytokines were also reduced in fat tissue of DFO-treated mice. These findings suggest that reduction of iron levels ameliorates adipocyte hypertrophy via suppression of oxidative stress, inflammatory cytokines, and macrophage infiltration, thereby breaking a vicious cycle in obesity.

[Hypertension as a predictive factor of effect of bevacizumab in treatment of colorectal cancer].

Bevacizumab is a monoclonal antibody that targets vascular endothelial growth factor (VEGF) for treatment of metastatic colorectal cancer. Recently, much evidence has suggested that bevacizumab-induced hypertension might be predictive of the effect of bevacizumab. The aim of our study is to retrospectively assess the relationship between the onset of hypertension and the activity of bevacizumab in Japanese metastatic colorectal cancer patients. Between July 2007 and December 2010, 36 patients (median age 66 years; 36-81 years) with metastatic colorectal cancer were assigned to receive bevacizumab in combination with either mFOLFOX6 (5-FU, levofolinate and oxaliplatin) or FOLFIRI (5-FU, levofolinate and irinotecan) at the Tokushima University Hospital. A patient who had increase by >20 mmHg in diastolic blood pressure or had increase to >150/100 mmHg or received antihypertensive treatment was defined as hypertensive. The objective response rate (ORR), disease control rate (DCR) and progression-free survival (PFS) were compared between the hypertensive group (n=10) and non-hypertensive group (n=26). ORR and DCR were 60.0% and 100%, respectively, in the hypertensive group and ORR and DCR were 23.1% and 80.8%, respectively, in the non-hypertensive group. These differences were statistically significant (p<0.05). The median PFS tended to be longer in the hypertensive group (65.0 weeks) than in the non-hypertensive group (40.0 weeks). Our data suggested that bevacizumab-induced hypertension may be predictive of the effect of bevacizumab in Japanese metastatic colorectal cancer patients.

Effects of a 1.5 T time-varying magnetic field on cell volume regulation of bovine adrenal chromaffin cells in hyposmotic media.

Effects of a time-varying magnetic field on cell volume regulation by hyposmotic stress in cultured bovine adrenal chromaffin cells were examined. Through regulatory volume decrease (RVD), cell volume of chromaffin cells that were incubated in a hypotonic medium initially increased, reached a peak and finally recovered to the initial value. Two hour exposure to a magnetic field and addition of cytochalasin D increased peak value and delayed return to initial value. Intracellular F-actin contents initially decreased but returned to normal levels after 10 sec. Two hour exposure to the magnetic field and addition of cytochalasin D continuously reduced the F-actin content. Results suggest that exposure to the magnetic field stimulated disruption of the actin cytoskeleton and that the disruption delayed the recovery to the volume prior to osmotic stress.

Pharmacology in health food: metabolism of quercetin in vivo and its protective effect against arteriosclerosis.

Quercetin, a member of the bioflavonoids family, has been proposed to have anti-atherogenic, anti-inflammatory, and anti-hypertensive properties leading to the beneficial effects against cardiovascular diseases. It was recently demonstrated that quercetin 3-O-ß-D-glucuronide (Q3GA) is one of the major quercetin conjugates in human plasma, in which the aglycone could not be detected. Although most of the in vitro pharmacological studies have been carried out using only the quercetin aglycone form, experiments using Q3GA would be important to discover the preventive mechanisms of cardiovascular diseases by quercetin in vivo. Therefore we examined the effects of the chemically synthesized Q3GA, as an in vivo form, on vascular smooth muscle cell (VSMC) disorders related to the progression of arteriosclerosis. Platelet-derived growth factor-induced cell migration and proliferation were inhibited by Q3GA in VSMCs. Q3GA attenuated angiotensin II-induced VSMC hypertrophy via its inhibitory effect on JNK and the AP-1 signaling pathway. Q3GA scavenged 1,1-diphenyl-2-picrylhydrazyl radical measured by the electron paramagnetic resonance method. In addition, immunohistochemical studies with monoclonal antibody 14A2 targeting the Q3GA demonstrated that the positive staining specifically accumulates in human atherosclerotic lesions, but not in the normal aorta. These findings suggest Q3GA would be an active metabolite of quercetin in plasma and may have preventative effects on arteriosclerosis relevant to VSMC disorders.

Identification of TMEM45B as a protein clearly showing thermal aggregation in SDS-PAGE gels and dissection of its amino acid sequence responsible for this aggregation.

SDS-PAGE is one of the most powerful experimental techniques used for the separation of proteins, and most proteins are separated according to their molecular size by this technique. However, exceptional proteins showing abnormal behavior in SDS-PAGE gels are known to exist. Thermal aggregation, rarely observed with membrane proteins, is one of the exceptional behaviors of proteins during SDS-PAGE, but detailed characterization of this aggregation has not yet been achieved. In the present study, we found that a putative membrane protein, TMEM45B, very clearly showed properties of thermal aggregation when it was expressed in COS7 cells and subjected to SDS-PAGE. We dissected the region of TMEM45B responsible for this aggregation, and found that of the seven putative transmembrane domains, a region comprising the 4th to 7th ones was essential for the thermal aggregation properties. We also demonstrated that these transmembrane domains, 4th to 7th, of TMEM45B conferred thermal aggregation properties on other proteins, by fusing this amino acid sequence to target proteins. The molecular mechanism causing thermal aggregation by TMEM45B is still uncertain, but TMEM45B could be utilized as a nice model to show clear thermal aggregation in SDS-PAGE gels.

Role of dipeptidyl peptidase IV (DPP4) in the development of dyslipidemia: DPP4 contributes to the steroid metabolism pathway.

AIMS: We previously reported that dipeptidyl peptidase IV (DPP4)-deficient rats were susceptible to dyslipidemia induced by streptozotocin (STZ). Hence, it is suggested that DPP4 is important for lipid metabolism. MAIN METHODS: In this study, to verify the role of DPP4 in the development of dyslipidemia, we carried out a microarray analysis of the livers of STZ-treated wild-type and DPP4-deficient rats and showed that the expression levels of genes involved in metabolic processes (steroid metabolic processes and cellular lipid metabolic processes) were significantly altered by STZ treatment. KEY FINDINGS: In the wild-type rats, the expression of hydroxysteroid (17-beta) dehydrogenase 2 (Hsd7b2), which catalyzes sex steroid synthesis from cholesterol, was significantly increased by about 15-fold after STZ treatment; however, it did not change in the DPP4-deficient rats. In the STZ untreated group of DPP4-deficient rats, the expression levels of cytochrome P450, subfamily 51 (Cyp51) and sterol-C4-methyl oxidase-like (Sc4mol), which catalyze intermediate steps in cholesterol synthesis, were significantly elevated compared to those of other groups. Similar results were demonstrated in HuH7-cells after DPP4 overexpression or the addition of human sera containing DPP4. SIGNIFICANCE: DPP4 is crucial for regulating the expression of factors related to steroid metabolism such as Cyp51, Sc4mol, and Hsd17b2, and DPP4 deficiency or inhibition may cause dyslipidemia.

Altered dipeptidyl peptidase-4 activity during the progression of hyperinsulinemic obesity and islet atrophy in spontaneously late-stage type 2 diabetic rats.

Altered dipeptidyl peptidase-4 (DPP4) activity during the progression of late-stage type 2 diabetes was measured in Otsuka Long-Evans Tokushima fatty (OLETF) rats. Compared with OLETF rats subjected to 30% food restriction, food-satiated OLETF rats exhibited spontaneous hyperphagic obesity, insulin resistance, hyperglycemia, hyperinsulinemia, and increased plasma DPP4 activity during the early phase of the experiment (up to ∼30 wk). Subsequently, their plasma DPP4 activity as well as their body weight, body fat, and plasma insulin concentration declined to control levels during the late phase, resulting in excessive polyuria, proteinuria, dyslipidemia, pancreatic islet atrophy, hypoinsulinemia, and diabetes, which changed from insulin-resistant diabetes to hypoinsulinemic diabetes secondary to progressive islet insufficiency, and their fasting blood glucose level remained high. Since plasma DPP4 activity demonstrated significant positive correlations with body weight and the fasting plasma insulin level but not with the fasting blood glucose level during the late stage of diabetes, body fat and fasting plasma insulin levels may be useful factors for predicting the control of plasma DPP4 activity. In contrast, pancreatic DPP4 activity was significantly increased, and the expression of pancreatic insulin was significantly reduced in late-stage diabetic OLETF rats, suggesting that a relationship exists between the activation of pancreatic DPP4 and insulin depletion in pancreatic islet atrophy. In conclusion, it is suggested that plasma DPP4 activity changes in accordance with the progression of hyperinsulinemic obesity and pancreatic islet atrophy. DPP4 activity may play an important role in insulin homeostasis.

Effects of exposure to a time-varying 1.5 T magnetic field on the neurotransmitter-activated increase in intracellular Ca(2+) in relation to actin fiber and mitochondrial functions in bovine adrenal chromaffin cells.

BACKGROUND: It has been reported that exposure to electromagnetic fields influences intracellular signal transduction. We studied the effects of exposure to a time-varying 1.5 T magnetic field on membrane properties, membrane cation transport and intracellular Ca(2+) mobilization in relation to signals. We also studied the mechanism of the effect of exposure to the magnetic field on intracellular Ca(2+) release from Ca(2+) stores in adrenal chromaffin cells. METHODS: We measured the physiological functions of ER, actin protein, and mitochondria with respect to a neurotransmitter-induced increase in Ca(2+) in chromaffin cells exposed to the time-varying 1.5 T magnetic field for 2h. RESULTS: Exposure to the magnetic field significantly reduced the increase in [Ca(2+)]i. The exposure depolarized the mitochondria membrane and lowered oxygen uptake, but did not reduce the intracellular ATP content. Magnetic field-exposure caused a morphological change in intracellular F-actin. F-actin in exposed cells seemed to be less dense than in control cells, but the decrease was smaller than that in cytochalasin D-treated cells. The increase in G-actin (i.e., the decrease in F-actin) due to exposure was recovered by jasplakinolide, but inhibition of Ca(2+) release by the exposure was unaffected. CONCLUSIONS AND GENERAL SIGNIFICANCE: These results suggest that the magnetic field-exposure influenced both the ER and mitochondria, but the inhibition of Ca(2+) release from ER was not due to mitochondria inhibition. The effect of eddy currents induced in the culture medium may indirectly influence intracellular actin and suppress the transient increase in [Ca(2+)]i.

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

BACKGROUND: 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). METHODS: 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. RESULTS: 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. CONCLUSIONS: Olmesartan attenuates ROS generation by PDGF, leading to the subsequent inhibition of Src/ BMK1/migration in an AT1 receptor-independent manner in RMCs.

Expression of soluble vascular endothelial growth factor receptor-1 in human monocyte-derived mature dendritic cells contributes to their antiangiogenic property.

The soluble form of vascular endothelial growth factor receptor-1 (sVEGFR-1) is produced from endothelial cells by alternative splicing of VEGFR-1 mRNA, and can inhibit angiogenesis by blocking the biological effects of VEGF. In this study, we show the expression of a large amount of sVEGFR-1 in human monocyte-derived mature dendritic cells (mDCs). As compared with monocytes and immature DCs, mDCs generated by TNF-alpha or soluble CD40L with IFN-gamma, but not LPS or other stimuli, preferentially produce sVEGFR-1. We also detected the mRNA of sVEGFR-1 generated by alternative splicing of VEGFR-1 mRNA in mDCs induced by TNF-alpha. The production of sVEGFR-1 showed a distinct contrast to those of VEGF in each DC matured with various stimuli. The supernatant of DCs matured with TNF-alpha or soluble CD40L with IFN-gamma showed inhibition of the tube formation of HUVECs, which was neutralized by anti-VEGFR-1 Ab, indicating that sVEGFR-1 secreted from mDCs was biologically active. Interestingly, the supernatant of mDCs generated with LPS increased HUVEC capillary-like formation in vitro. The ratio of sVEGFR-1 to VEGF clearly reflected the net angiogenic property of mDCs. Administration of mDCs induced by TNF-alpha into the s.c. tumor of PC-14 cells implanted in SCID mice demonstrated the inhibition of tumor growth via reduction of the number of CD31-positive vessels, indicating their in vivo antiangiogenic potential. These results suggest that sVEGFR-1 produced by mDCs contribute to their antiangiogenic property, and the ratio of sVEGFR-1 to VEGF might be a useful tool for evaluating their ability to regulate angiogenesis mediated by VEGF.