Germline mutations in TMEM127 confer susceptibility to pheochromocytoma

Pheochromocytomas, which are catecholamine-secreting tumors of neural crest origin, are frequently hereditary(1). However, the molecular basis of the majority of these tumors is unknown(2). We identified the transmembrane-encoding gene TMEM127 on chromosome 2q11 as a new pheochromocytoma susceptibility gene. In a cohort of 103 samples, we detected truncating germline TMEM127 mutations in approximately 30% of familial tumors and about 3% of sporadic-appearing pheochromocytomas without a known genetic cause. The wild-type allele was consistently deleted in tumor DNA, suggesting a classic mechanism of tumor suppressor gene inactivation. Pheochromocytomas with mutations in TMEM127 are transcriptionally related to tumors bearing NF1 mutations and, similarly, show hyperphosphorylation of mammalian target of rapamycin (mTOR) effector proteins. Accordingly, in vitro gain-of-function and loss-of-function analyses indicate that TMEM127 is a negative regulator of mTOR. TMEM127 dynamically associates with the endomembrane system and colocalizes with perinuclear (activated) mTOR, suggesting a subcompartmental-specific effect. Our studies identify TMEM127 as a tumor suppressor gene and validate the power of hereditary tumors to elucidate cancer pathogenesis.

Measurements of neutral atom diffusion and electron-ion recombination by laser enhanced ionisation and planar laser induced fluorescence in an air-acetylene flame

The spatial and temporal evolution of a depleted atomic distribution created by laser enhanced ionisation (LEI) was employed to determine both a diffusion coefficient for sodium (Na) and an electron (e(-)) and sodium ion recombination rate coefficient in an analytical air-C2H2 flame. A depleted distribution of neutral sodium atoms was produced in a flame by ionising approximately 80% of the irradiated sodium atoms in a well defined region using a two step LEI excitation scheme. Following depletion by ionisation, planar laser induced fluorescence (PLIF) images of the depleted region recorded the diffusion and decay of the depleted Na distribution for different depletion-probe delays. From measurements of the diffused width of the distribution, an accurate diffusion coefficient D = (1.19 +/- 0.03) x 10(-3) m(2) s(-1) for Na was determined in teh burnt gases of the flame. Measurements of the integrated fluorescence intensity in the depleted region for different depletion-probe delays were related to an increase in atomic sodium concentration caused by electron-ion recombination. At high concentrations (greater than or equal to 50 mu g ml(-1)), where the electron and ion concentrations in the depleted region were assumed equal, a recombination rate coefficient of 4.2 x 10(-9) cm(3) s(-1) was calculated. (C) 1997 Elsevier Science B.V.

Molecular basis of infantile reversible cytochrome c oxidase deficiency myopathy

Childhood-onset mitochondrial encephalomyopathies are usually severe, relentlessly progressive conditions that have a fatal outcome. However, a puzzling infantile disorder, long known as `benign cytochrome c oxidase deficiency myopathy` is an exception because it shows spontaneous recovery if infants survive the first months of life. Current investigations cannot distinguish those with a good prognosis from those with terminal disease, making it very difficult to decide when to continue intensive supportive care. Here we define the principal molecular basis of the disorder by identifying a maternally inherited, homoplasmic m.14674T > C mt-tRNA(Glu) mutation in 17 patients from 12 families. Our results provide functional evidence for the pathogenicity of the mutation and show that tissue-specific mechanisms downstream of tRNA(Glu) may explain the spontaneous recovery. This study provides the rationale for a simple genetic test to identify infants with mitochondrial myopathy and good prognosis.

Muscle sympathetic nervous activity in depressed patients before and after treatment with sertraline

Background Sympathetic hyperactivity is one of the mechanisms involved in the increased cardiovascular risk associated with depression, and there is evidence that antidepressants decrease sympathetic activity. Objectives We tested the following two hypotheses: patients with major depressive disorder with high scores of depressive symptoms (HMDD) have augmented muscle sympathetic nervous system activity (MSNA) at rest and during mental stress compared with patients with major depressive disorder with low scores of depressive symptoms (LMDD) and controls; sertraline decreases MSNA in depressed patients. Methods Ten HMDD, nine LMDD and 11 body weight-matched controls were studied. MSNA was directly measured from the peroneal nerve using microneurography for 3 min at rest and 4 min during the Stroop color word test. For the LMDD and HMDD groups, the tests were repeated after treatment with sertraline (103.3 +/- 40 mg). Results Resting MSNA was significantly higher in the HMDD [29.1 bursts/min (SE 2.9)] compared with LMDD [19.9 (1.6)] and controls [22.2 (2.0)] groups (P=0.026 and 0.046, respectively). There was a significant positive correlation between resting MSNA and severity of depression. MSNA increased significantly and similarly during stress in all the studied groups. Sertraline significantly decreased resting MSNA in the LMDD group and MSNA during mental stress in LMDD and HMDD groups. Sertraline significantly decreased resting heart rate and heart rate response to mental stress in the HMDD group. Conclusion Moderate-to-severe depression is associated with increased MSNA. Sertraline treatment reduces MSNA at rest and during mental challenge in depressed patients, which may have prognostic implications in this group. J Hypertens 27:2429-2436 (c) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

Oral tolerance attenuates changes in in vitro lung tissue mechanics and extracellular matrix remodeling induced by chronic allergic inflammation in guinea pigs

Oral tolerance attenuates changes in in vitro lung tissue mechanics and extracellular matrix remodeling induced by chronic allergic inflammation in guinea pigs. J Appl Physiol 104: 1778-1785, 2008. First published April 3, 2008; doi:10.1152/japplphysiol.00830.2007.-Recent studies emphasize the presence of alveolar tissue inflammation in asthma. Immunotherapy has been considered a possible therapeutic strategy for asthma, and its effect on lung tissue had not been previously investigated. Measurements of lung tissue resistance and elastance were obtained before and after both ovalbumin and acetylcholine challenges. Using morphometry, we assessed eosinophil and smooth muscle cell density, as well as collagen and elastic fiber content, in lung tissue from guinea pigs with chronic pulmonary allergic inflammation. Animals received seven inhalations of ovalbumin (1-5 mg/ml; OVA group) or saline (SAL group) during 4 wk. Oral tolerance (OT) was induced by offering ad libitum ovalbumin 2% in sterile drinking water starting with the 1st inhalation (OT1 group) or after the 4th (OT2 group). The ovalbumin-exposed animals presented an increase in baseline and in postchallenge resistance and elastance related to baseline, eosinophil density, and collagen and elastic fiber content in lung tissue compared with controls. Baseline and post-ovalbumin and acetylcholine elastance and resistance, eosinophil density, and collagen and elastic fiber content were attenuated in OT1 and OT2 groups compared with the OVA group. Our results show that inducing oral tolerance attenuates lung tissue mechanics, as well as eosinophilic inflammation and extracellular matrix remodeling induced by chronic inflammation.

IRF8 Mutations and Human Dendritic-Cell Immunodeficiency

BACKGROUND The genetic analysis of human primary immunodeficiencies has defined the contribution of specific cell populations and molecular pathways in the host defense against infection. Disseminated infection caused by bacille Calmette-Guerin (BCG) vaccines is an early manifestation of primary immunodeficiencies, such as severe combined immunodeficiency. In many affected persons, the cause of disseminated BCG disease is unexplained. METHODS We evaluated an infant presenting with features of severe immunodeficiency, including early-onset disseminated BCG disease, who required hematopoietic stem-cell transplantation. We also studied two otherwise healthy subjects with a history of disseminated but curable BCG disease in childhood. We characterized the monocyte and dendritic-cell compartments in these three subjects and sequenced candidate genes in which mutations could plausibly confer susceptibility to BCG disease. RESULTS We detected two distinct disease-causing mutations affecting interferon regulatory factor 8 (IRF8). Both K108E and T80A mutations impair IRF8 transcriptional activity by disrupting the interaction between IRF8 and DNA. The K108E variant was associated with an autosomal recessive severe immunodeficiency with a complete lack of circulating monocytes and dendritic cells. The T80A variant was associated with an autosomal dominant, milder immunodeficiency and a selective depletion of CD11c+CD1c+ circulating dendritic cells. CONCLUSIONS These findings define a class of human primary immunodeficiencies that affect the differentiation of mononuclear phagocytes. They also show that human IRF8 is critical for the development of monocytes and dendritic cells and for antimycobacterial immunity. (Funded by the Medical Research Council and others.)

Dobutamine Stress Echocardiography in Heart Transplant Recipients` Evaluation: The Role of Reinnervation

Introduction. Orthotopic heart transplantation renders the recipient denervated. This remodeling of the intrinsic cardiac nervous system should be taken in account during functional evaluation for allograft coronary artery disease. Dobutamine stress echocardiography (DSE) has been used to detect patients at greater risk. The aim of this study was to determine whether patients with various autonomic response levels, and supposed reinnervation patterns, show the same response to DSE. Methods. We studied 20 patients who had survived more than 5 years after orthotopic heart transplantation. All patients underwent a Holter evaluation. We considered patients with low variability to be those with less than a 40-bpm variation from the lowest to highest heart rate, so-called ""noninnenervated"" (group NI). Patients who had 40-bpm or more variation were considered to show high variability and called ""reinnervated"" (group RI). After that, all patients performed an ergometric test and DSE. Results. Groups were defined as NI (n = 9) and RI (n = 11). Ergometric tests confirmed this response with NI patients showing less variability when compared to RI patients (P = .0401). During DSE, patients showed similar median heart rate responses according to the dobutamine dose. Spearmen correlation showed r = 1.0 (P = .016). Conclusions: DES was effective to reach higher heart rates, probably related to catecholamine infusion. These findings may justify a better response when evaluating cardiac allograft vasculopathy in heart transplant patients.

Serotonin and Sensitivity to Trauma-Related Exposure in Selective Serotonin Reuptake Inhibitors-Recovered Posttraumatic Stress Disorder

Background: Selective serotonin reuptake inhibitors (SSRIs) are first-line treatments for posttraumatic stress disorder (PTSD). Serotonergic (5HT) attenuation of stress sensitivity is postulated from SSRIs` effects in other anxiety disorders, and we studied this in PTSD. Methods: Ten patients with PTSD fully recovered on SSRIs (Clinical Global Impression Scale-I 1 and 2) were enrolled in the study. Patients were tested on two occasions I week apart; in each session, they received a drink containing large neutral amino acids (LNAAs) either with (sham tryptophan depletion [STD], control) or without (acute tryptophan depletion [ATD]) tryptophan. At 5.5 hours after the drink, subjects were exposed to a trauma-related exposure challenge. Self-reports of PTSD (visual analogue scales [VAS] and the Davidson Trauma Scale [DTSI), anxiety (Spielberger State Inventory [STAI] Form Y-1), and mood (Profile of Mood States [POMS]) were obtained. Heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure were also measured. Results: The trauma-related exposure challenge induced anxiety on both days, with more marked responses on the ATD day according to VAS, DTS, POMS, and DBP (p < .05). A trend of significance (.1 > p >.05) was observed for STAI Form Y-1, HR, and SBP. Conclusions: These data demonstrate that ATD accentuates responses to trauma-related stimuli in SSRI-recovered PTSD. They also suggest that SSRI-induced increases in serotonin function restrain PTSD symptoms, especially under provocation, supporting a role for serotonin in mediating stress resilience.

Immunoendocrinology of the Thymus in Chagas Disease

During immune response to infectious agents, the host develops an inflammatory response which could fail to eliminate the pathogen or may become dysregulated. In this case, the ongoing response acquires a new status and turns out to be detrimental. The same elements taking part in the establishment and regulation of the inflammatory response (cytokines, chemokines, regulatory T cells and counteracting compounds like glucocorticoids) may also mediate harmful effects. Thymic disturbances seen during Trypanosoma cruzi (T. cruzi) infection fit well with this conceptual framework. After infection, this organ suffers a severe atrophy due to apoptosis-induced thymocyte exhaustion, mainly affecting the immature double-positive (DP) CD4+CD8+ population. Thymus cellularity depletion, which occurs in the absence of main immunological mediators involved in anti-T. cruzi defense, seems to be linked to a systemic cytokine/hormonal imbalance, involving a dysregulated increase in Tumor Necrosis Factor alpha (TNF-alpha) and corticosterone hormone levels. Additionally, we have found an anomalous exit of potentially autoimmune DP cells to the periphery, in parallel to a shrinkage in the compartment of natural regulatory T cells. In this context, our data clearly point to the view that the thymus is a target organ of T. cruzi infection. Preserved thymus may be essential for the development of an effective immune response against T. cruzi, but this organ is severely affected by a dysregulated circuit of proinflammatory cytokines and glucocorticoids. Also, the alterations observed in the DP population might have potential implications for the autoimmune component of human Chagas disease. Copyright (C) 2011 S. Karger AG, Basel

Effects of Acute Cold Stress on Phagocytosis of Apoptotic Cells: The Role of Corticosterone

Background and Aims: Stress can alter many aspects of the immune response, and many studies have been conducted on the effects of stress on inflammatory processes, but little is known about its influence on the resolution of inflammation in tissue homeostasis, which includes the clearance of apoptotic cells by macrophages in a non-phlogistic way. In the present study, we investigated the effect of acute cold stress on the phagocytosis of apoptotic cells by macrophages. Methods: Mice were submitted to acute cold stress (4 degrees C for 4 h) and the capacity of peritoneal macrophages to phagocyte apoptotic thymocytes and to secrete anti-inflammatory cytokines was evaluated. Plasma corticosterone and catecholamine levels were investigated to assess their effect on the phagocytic capacity of macrophages in vitro. Results: We showed that acute cold stress decreases phagocytosis of apoptotic cells at the inflammatory site by lipopolysaccharide-activated macrophages but did not affect resting macrophages. The inhibitory effect on phagocytosis is accompanied by a reduced level of TGF-beta and higher IL-10 secretion. After stress, plasma concentrations of corticosterone increased 6-fold, epinephrine 2-fold and norepinephrine 1.7-fold compared to control mice. In vitro experiments showed that the decrease in phagocytosis after stress could be attributed, at least in part, to the effects of corticosterone; epinephrine and norepinephrine had no effect. Conclusions: The current study shows that acute cold stress decreases phagocytosis of apoptotic cells from an inflammatory environment by macrophages, and this inhibition is mediated by the intracellular glucocorticoid receptor. Copyright (C) 2009 S. Karger AG, Basel

Chemical sympathectomy further increases muscle protein degradation of acutely diabetic rats

The present work investigated the role of the sympathetic nervous system (SINS) in the control of protein degradation in skeletal muscles from rats with streptozotocin (STZ)-induced diabetes. Diabetes (1, 3, and 5 days after STZ) induced a significant increase in the norepinephrine content of soleus and EDL muscles, but it did not affect plasma catecholamine levels. Chemical sympathectomy induced by guanethidine (100 mg/kg body weight, for 1 or 2 days) reduced muscle norepinephrine content to negligible levels (less than 5%), decreased plasma epinephrine concentration, and further increased the high rate of protein degradation in muscles from acutely diabetic rats. The rise in the rate of proteolysis (nmol.mg wet wt(-1).2h(-1)) in soleus from 1-day diabetic sympathectomized rats was associated with increased activities of lysosomal (0.127 +/- 0.008 vs. 0.086 +/- 0.013 in diabetic control) and ubiquitin (Ub)-proteasome-dependent proteolytic pathways (0.154 +/- 0,007 vs. 0.121 +/- 0.006 in diabetic control). Increases in Ca2+-depenclent (0.180 +/- 0.007 vs. 0.121 +/- 0.011 in diabetic control) and Ub-proteasome-dependent proteolytic systems (0.092 +/- 0.003 vs. 0.060 +/- 0.002 in diabetic control) were observed in EDL from 1-day diabetic sympathectomized rats. The lower phosphorylation levels of AKT and Foxo3a in EDL muscles from 3-day diabetic rats were further decreased by sympathectomy. The data suggest that the SNS exerts acute inhibitory control of skeletal muscle proteolysis during the early stages of diabetes in rats, probably involving the AKT/Foxo signaling pathway.

Effects of Pentoxyfilline and Heparin on Reperfusion Injury Island Skin Flaps in Rats Exposed to Tobacco

Background. Ischemia-reperfusion injury is believed to be a major cause of transferred skin flap failure. Cigarette smoking is known to be associated with endogenous antioxidant depletion, hypercoagulability, and cutaneous vasoconstriction. This investigation was carried out to study possible effects of pentoxyfilline or heparin on rat skin reperfusion injury under tobacco exposure. Materials and Methods. Thirty-six rats were randomized into two major groups: 18 were exposed to cigarette smoke during a 4 wk period prior to surgery; the remaining 18 underwent a sham smoking procedure. Each group was further divided into three equal subgroups: heparin, pentoxyfilline, and saline solution. One identical skin flap was raised in each animal. The vasculature of the flap was clamped for 3 h and reperfused for 5 min. A venous blood sample was obtained from the flap after reperfusion for serum malondialdehyde (MDA) and myeloperoxidase (MPO) analysis. Flap survival was assessed 7 d after the procedure. Results. The lipid peroxidation levels and flap necrosis were significantly higher in the cigarette-smoking group skin flaps. There was also a decrease of MPO activity in this group compared with the nonsmoking group. Heparin-treated rats had significantly lower MDA levels and showed the most viable percent area among smoking rats. Conclusions. These data suggest that heparin had a significant beneficial effect both on flap survival and on the lipid peroxidation reduction after smoke exposure in the rat axial-pattern skin flap subjected to ischemia and reperfusion injury. Pharmacologic therapy may represent an alternative way to counteract tobacco effects in flap surgery in emergency situations. (C) 2010 Elsevier Inc. All rights reserved.

Effects of creatine supplementation on homocysteine levels and lipid peroxidation in rats

Hyperhomocysteinaemia is an independent risk factor for CVD. Recent data show a relationship between homocysteine (Hcy) and free radical formation. Since creatine synthesis is responsible for most of the methyl group transfers that result in Hcy formation, creatine supplementation might inhibit Hcy production and reduce free radical formation. The present study investigated the effects of creatine supplementation on Hcy levels and lipid peroxidation biomarkers. Thirty rats were divided into three groups: control group; diet with creatine group (DCr; 2% creatine in the diet for 28 d); creatine overload plus diet with creatine group (CrO + D; 5 g creatine/kg by oral administration for 5 d + 2 % in the diet for 23 d). Plasma Hcy was significantly lower (P<0.05) in DCr (7.5 (SD 1.2) mu mol/l) and CrO + D (7.2 (SD 1.7) mu mol/l) groups compared with the control group (12.4 (SD 2.2) mu mol/l). Both plasma thiobarbituric acid-reactive species (TBARS) (control, 10 (SD 3.4); DCr, 4.9 (So 0.7); CrO + D, 2.4 (SD 1) mu mol/l) and plasma total glutathione (control, 4.3 (SD 1.9); DCr, 2.5 (SD 0.8); CrO + D, 1.8 (SD 0.5) mu mol/l) were lower in the groups that received creatine (P<0.05). In addition, Hcy showed significant negative correlation (P<0.05) with plasma creatine (r - 0.61) and positive correlation with plasma TBARS (r 0.74). Plasma creatine was negatively correlated with plasma TBARS (r - 0.75) and total peroxide (r - 0.40). We conclude that creatine supplementation reduces plasma Hcy levels and lipid peroxidation biomarkers, suggesting a protective role against oxidative damage. Modulating Hcy fort-nation may, however, influence glutathione synthesis and thereby affect the redox state of the cells.

The influence of glutathione modulators on the course of Leishmania major infection in susceptible and resistant mice

Glutathione (GSH) has an important dual role in parasite-host relationship in Leishmania major infection. Our previous studies showed that both antioxidant systems, glutathione and trypanothione/trypanothione reductase, participate in the protection of Leishmania against the toxic effect of nitrogen-derived reactive species. On the other hand, GSH also is very important to the modulation of the effective immune response, inducting NO production and leishmanicidal activity of macrophages. In the present study, we investigated the role of host GSH during the course of L. major infection, analysing the size of footpad lesions and parasite load from mice treated with two GSH modulators, N-acethyl-L-cysteine (NAC) and buthionine sulphoximine (BSO). Resistant mice treated with BSO, which depletes GSH develop exacerbated lesions, but only harbour higher parasite load in their lesions 2 weeks post-infection. Although the NAC treatment does not affect the footpad lesions development in susceptible BALB/c mice, it significantly reduced the tissue parasitism in the lesions throughout the course of infection. Interestingly, the treatment with BSO did not change the course of L. major infection on susceptible mice when compared with nontreated mice. These results suggest that GSH is an important antioxidant modulator during anti-Leishmania immune response in vivo.

Neutrophil migration induced by IL-1 beta depends upon LTB4 released by macrophages and upon TNF-alpha and IL-1 beta released by mast cells

In the present study, we investigate whether mast cells and macrophages are involved in the control of IL-1 beta-induced neutrophil migration, as well as the participation of chemotactic mediators. IL-1 beta induced a dose-dependent neutrophil migration to the peritoneal cavity of rats which depends on LTB4, PAF and cytokines, since the animal treatment with inhibitors of these mediators (MK 886, PCA 4248 and dexamethasone respectively) inhibited IL-1 beta-induced neutrophil migration. The neutrophil migration induced by IL-1 beta is dependent on mast cells and macrophages, since depletion of mast cells reduced the process whereas the increase of macrophage population enhanced the migration. Moreover, mast cells or macrophages stimulated with IL-1 beta released a neutrophil chemotactic factor, which mimicked the neutrophil migration induced by IL-1 beta. The chemotactic activity of the supernatant of IL-1 beta-stimulated macrophages is due to the presence of LTB4, since MK 886 inhibited its release. Moreover, the chemotactic activity of IL-1 beta-stimulated mast cells supernatant is due to the presence of IL-1 beta and TNF-alpha, since antibodies against these cytokines inhibited its activity. Furthermore, significant amounts of these cytokines were detected in the supernatant. In conclusion, our results suggest that neutrophil migration induced by IL-1 beta depends upon LTB4 released by macrophages and upon IL-1 beta and TNF alpha released by mast cells.