The Regulation of nNOS During Neuronal Differentiation and the Effect of Nitric Oxide on Hdm2-p53 Binding: a Dissertation

Nitric oxide is a ubiquitous signaling molecule with both physiological and pathological functions in biological systems. Formed by the enzymatic conversion of arginine to citrulline, NO, has known roles in circulatory, immune and nervous tissues. In the nervous system nitric oxide has been implicated in long-term potentiation, neurotransmitter release, channel function, neuronal protection and neuronal degeneration. Much of our work has focused on yet another role for nitric oxide in cells, namely, neuronal differentiation. During development, neuronal differentiation is closely coupled with cessation of proliferation. We use nerve growth factor (NGF)-induced differentiation of PC12 pheochromocytoma cells as a model and find a novel signal transduction pathway that blocks cell proliferation. Treatment of PC12 cells with NGF leads to induction of nitric oxide synthase (NOS). The resulting nitric oxide (NO) acts as a second messenger, activating the p21(WAF1) promoter and inducing expression of p21(WAF1) cyclin-dependent kinase inhibitor. NO activates the p21(WAF1) promoter by p53-dependent and p53-independent mechanisms. Blocking production of NO with an inhibitor of NOS reduces accumulation of p53, activation of the p21(WAF1) promoter, expression of neuronal markers, and neurite extension. To deternine whether p21(WAF1) is required for neurite extension, we prepared a PC12 line with an inducible p21(WAF1) expression vector. Blocking NOS with an inhibitor decreases neurite extension, but induction of p21(WAF1) with isopropyl-1-thio-beta-D-galactopyranoside restored this response. Levels of p21(WAF1) induced by isopropyl-1-thio-beta-D-galactopyranoside were similar to those induced by NGF. Therefore, we have identified a signal transduction pathway that is activated by NGF; proceeds through NOS, p53 and p21(WAF1) to block cell proliferation; and is required for neuronal differentiation by PC12 cells. In further studies of this pathway, we have examined the role of MAP kinase pathways in neuronal nitric oxide synthase (nNOS) induction during the differentiation of PC12 cells. In NGF-treated PC12 cells, we find that nNOS is induced at RNA and protein levels, resulting in increased NOS activity. We note that neither nNOS mRNA, nNOS protein nor NOS activity is induced by NGF treatment in cells that have been infected with a dominant negative Ras adenovirus. We have also used drugs that block MAP kinase pathways and assessed their ability to inhibit nNOS induction. Even though U0126 and PD98059 are both MEK inhibitors, we find that U0126, but not PD98059, blocks nNOS induction and NOS activity in NGF-treated PC12 cells. Also, the p38 kinase inhibitor, SB 203580, does not block nNOS induction in our clone of PC12 cells. Since the JNK pathway is not activated in NGF-treated PC12 cells, we determine that the Ras-ERK pathway and not the p38 or JNK pathway is required for nNOS induction in NGF-treated PC12 cells. We find that U0l26 is much more effective than PD98059 in blocking the Ras-ERK pathway, thereby explaining the discrepancy in nNOS inhibition. We conclude that the Ras-ERK pathway is required for nNOS induction. The activation of soluble guanylate cyclase and the production of cyclic GMP is one of the best characterized modes of NO action. Having shown that inhibition of NOS blocks PC12 cell differentiation we tested whether nitric oxide acts through soluble guanylate cyclase to lead to cell cycle arrest and neuronal differentiation. Unlike NOS inhibition, the inhibition of soluble guanylate cylcase does not block the induction of neuronal markers. Moreover, treatment of NGF-treated, NOS-inhibited PC12 cells with a soluble analog of cyclic GMP was unable to restore differentiation of those cells. Hence, cGMP is not a component of this pathway and we had to consider other mechanisms of NO action. It has become increasingly evident that another manner by which NO may exert its effects is by S-nitrosylation of cysteine residues. We tested, in vitro whether nitric oxide may control p53 by S-nitrosylation and inactivation of the p53 negative regulator, Hdm2. Treatment of Hdm2 with a nitric oxide donor inhibits Hdm2-p53 binding, the first step in Hdm2 regulation of p53. The presence of cysteine or DTT blocks this inhibition of binding. Moreover, nitric oxide inhibition of Hdm2-p53 binding was found to be reversible. Sulfhydryl-sensitivity and reversibility are consistent with nitrosylation. Finally, we have identified a critical cysteine residue that nitric oxide modifies in order to disrupt Hdm2-p53 binding. Mutation of this residue from a cysteine to an alanine does not interfere with binding but rather eliminates the sensitivity of Hdm2 to nitric oxide inactivation

Gaseous Carbon Emissions (Methane and Carbon Dioxide) from Wetland Soils in a Re-created Everglades Landscape

Reducing the rates of greenhouse gas (GHG) emissions is critical in combatting global climate change. Carbon dioxide (CO2) and methane (CH4) are the two most important carbon-based GHGs, for their atmospheric warming potential. Wetlands such as the Florida Everglades play major roles in the global carbon cycle, as varying hydrologic conditions lead to differential production rates of these two GHGs. This study measured CO2 and CH4 emissions in a re-created Everglades ridge-and-slough wetland, where water levels were controlled to reflect natural flood patterns. As expected, lower elevations were flooded longer and produced more CH4, while higher elevations produced more CO2. Since CH4 has a relatively high global warming potential, CO2 production would need to be 70 times that of CH4, to balance their GHG output. The average ratio of CO2 to CH4 across elevations was 22.0 (mol:mol), indicating that future water management within wetlands should consider GHG production potential

Neurogenin 3-expressing progenitor cells in the gastrointestinal tract differentiate into both endocrine and non-endocrine cell types

AbstractMice deficient for the transcription factor neurogenin 3 (ngn3) fail to develop endocrine cells in the intestine and pancreas and show partial endocrine differentiation in the stomach. We expressed Cre recombinase under control of a ngn3 BAC to achieve high fidelity cell lineage tracing in vivo to determine whether endocrine cells in these organs differentiate from NGN3+ precursor cells. Our results indicate that all small intestinal enteroendocrine cells arise from ngn3-expressing cells and confirm that NGN3+ cells give rise to all pancreatic endocrine cells as noted previously. By examining mice at a developmental stage when all of the cell types in the stomach have differentiated, we have delineated region-associated differences in endocrine differentiation. A much smaller fraction of endocrine cells populating the acid-producing region of the stomach is derived from NGN3+ precursor in contrast to the antral–pyloric region. Unexpectedly, ngn3 is expressed in cells that adopt non-endocrine cell fates including significant fractions of goblet and Paneth cells in the intestine and a small number of duct and acinar cells in the pancreas. Rarely, ngn3 was expressed in pluripotent cells in intestinal crypts with resultant labeling of an entire crypt–villus unit. Thus, ngn3 expression occurs in mixed populations of immature cells that are not irreversibly committed to endocrine differentiation

Klinisches Management des Ullrich-Turner-Syndroms: Eine retrospektive Langzeitstudie an der Universitätskinderklinik Leipzig

In dieser retrospektiven klinischen Studie wurden die Akten von 89 Patientinnen mit Ullrich-Turner-Syndrom ausgewertet, die zwischen 1974 und 2004 in der Universitätsklinik und Poliklinik für Kinder und Jugendliche in Leipzig behandelt worden sind. Berücksichtigt wurde die Verteilung der Karyotypen im Patientenkollektiv sowie das Auftreten von assoziierten Begleiterkrankungen. Das Alter bei Diagnosestellung, die Größe bei Diagnosestellung und die Gründe für die Verdachtsdiagnose Ullrich-Turner-Syndrom wurden analysiert. Darüber hinaus untersuchte der Autor die durchgeführten Maßnahmen zur Pubertätsinduktion im Hinblick auf ihren Beginn und Erfolg sowie deren Einfluss auf die Wachstumraten. Gut 50% der Patientinnen besaßen den Karyotyp 45,X, die anderen Karyotypen setzten sich aus Mosaiken zusammen. Assoziierte Begleiterkrankungen waren im Patientenkollektiv unterrepräsentiert. Das durchschnittliche Alter bei Diagnosestellung betrug 8,21 Jahre, es fiel während des Beobachtungszeitraumes signifikant ab. Der durchschnittliche Größen-SDS zum Zeitpunkt der Diagnosestellung betrug -2,86. Es wurde, verglichen mit den Empfehlungen der Leitlinien, eine verspätete Diagnosestellung konstatiert. Die Pubertätsinduktion begann mit durchschnittlich 13,93 Jahren mit einer signifikanten Reduktion im Verlauf. Die Dauer vom Beginn der Pubertätsinduktion bis zum Eintreten der Menarche betrug 2,51 Jahre, die Dauer vom Tannerstadium B2 zum Stadium B5 betrug gut 27 Monate. Eine Menarche wurde bei nur 65% der Patientinnen sicher beobachtet. Die Ergebnisse wurden kritisch überprüft und in den Kontext anderer Studien eingeordnet. Aus den Ergebnissen wurde gefolgert, dass das Ullrich-Turner-Syndrom, trotz einer positiven Entwicklung in den letzten Jahren, noch immer zu spät diagnostiziert wurde. Die Pubertätsinduktion verlief trotz der verzögerten Diagnosestellung hinsichtlich der Entwicklung der Tannerstadien erfolgreich. Demgegenüber blieb die Induktion der Menarche nur mäßig erfolgreich. Eine Beeinflussung der Wachstumraten durch die Östrogentherapie wurde nicht beobachtet

Agroecología y transición agroalimentaria

La conferencia tenía como objetivo introducir la Agroecología de manera holística, así como su propio término lo requiere. Se abordó desde la definición del concepto, así como el de agroecosistema, utilizando también la comparativa con el sistema de producción convencional desde la Agronomía, para profundizar sobre las diferencias y las nuevas aportaciones que trae este enfoque transdisciplinar. El eje del discurso fue la sostenibilidad, en su marco más amplio, como el objetivo central de la Agroecología. El análisis de sus diversas dimensiones, ambiental, social y económica, sirvió para introducir las diferentes problemáticas actuales, como la crisis del sistema agroalimentario. Se puso énfasis en las consecuencias de la agricultura industrializada o intensiva, tratando más en profundidad temas como el abandono rural, la erosión genética de variedades locales, la pérdida de diversidad cultivada, y la deficiente gestión de recursos como el agua. Además, se presentaron varios aspectos de la transición agroecológica como enfoque necesario para un cambio de modelo agrario. Se trataron temas aplicados para esta transición sobre todo en el medio de producción agrícola, como por ejemplo la introducción de prácticas que pongan el foco en la conservación del suelo, agua, energía y recursos biológicos. Se propuso una reflexión sobre el decrecimiento, modelos de consumo, la agricultura ecológica como vía para un manejo sostenible, los canales cortos de comercialización, y un amplio abanico de propuestas para esta necesaria transición. Finalmente, como ejemplo de un trabajo de investigación aplicado en Agroecología, se presentó un resumen de un estudio sobre la recuperación y puesta en valor de las variedades locales de higuera en el Valle del Guadalhorce. Paralelamente, en una segunda parte de esta conferencia se pudo analizar un caso concreto de cultivo en una finca agroecológica.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Dissociation of liner from cup in THA: does liner damage affect the risk of dissociation?

INTRODUCTION A rare catastrophic failure of modular component Total Hip Arthroplasty is dissociation between liner and cup, which has been associated with component malposition and/or impingement and seems to be more frequently associated with the Pinnacle system. The goal of this study was to evaluate the resistance of a polyethylene liner to lever-out-forces of the Pinnacle locking mechanism and the locking mechanisms of two other current cup/liner systems using a standardized testing method (ASTM). MATERIALS AND METHODS Five of each of the following cups were evaluated with their corresponding polyethylene liners: Pinnacle Multihole cup with and without intact anti-rotation tabs (ART's); Allofit-S-Alloclassic and Plasmafit Plus7 cups. The ASTM test set-up was used to evaluate the lever-out force resulting in liner dissociation for each construct. RESULTS The Pinnacle construct with intact ARTs required the greatest force (F) to achieve dissociation (263.2 ± 79.2 N) followed by the Plasmafit Plus7 (185.8 ± 36.9 N) and the Allofit-S (101.4 ± 35.3 N) constructs, respectively. However, after removal of the ARTs, the Pinnacle system required the least force to achieve dissociation (75.1 ± 22.2 N) (p < 0.001). CONCLUSIONS The intact Pinnacle system appeared the most stable in lever-out tests when compared to the other systems. However, after removal of the ARTs, the Pinnacle system required the least force for dissociation, consistent with locking mechanism failure, and suggesting that the ARTs are a critical component of the locking mechanism. Our findings are consistent with the clinical experience of dissociated Pinnacle constructs displaying damaged or missing ARTs, and that damage to these may increase risk of liner dissociation

S-Nitrosylation of mitochondrial caspases

Caspase-3 is a cysteine protease located in both the cytoplasm and mitochondrial intermembrane space that is a central effector of many apoptotic pathways. In resting cells, a subset of caspase-3 zymogens is S-nitrosylated at the active site cysteine, inhibiting enzyme activity. During Fas-induced apoptosis, caspases are denitrosylated, allowing the catalytic site to function. In the current studies, we sought to identify the subpopulation of caspases that is regulated by S-nitrosylation. We report that the majority of mitochondrial, but not cytoplasmic, caspase-3 zymogens contain this inhibitory modification. In addition, the majority of mitochondrial caspase-9 is S-nitrosylated. These studies suggest that S-nitrosylation plays an important role in regulating mitochondrial caspase function and that the S-nitrosylation state of a given protein depends on its subcellular localization

Observation of exciton redshift-blueshift crossover in monolayer WS2

We report a rare atom-like interaction between excitons in monolayer WS2, measured using ultrafast absorption spectroscopy. At increasing excitation density, the exciton resonance energy exhibits a pronounced redshift followed by an anomalous blueshift. Using both material-realistic computation and phenomenological modeling, we attribute this observation to plasma effects and an attraction-repulsion crossover of the exciton-exciton interaction that mimics the Lennard-Jones potential between atoms. Our experiment demonstrates a strong analogy between excitons and atoms with respect to inter-particle interaction, which holds promise to pursue the predicted liquid and crystalline phases of excitons in two-dimensional materials

A history of opioid exposure in females increases the risk of metabolic disorders in their future male offspring

© 2019 Society for the Study of Addiction Worldwide consumption of opioids remains at historic levels. Preclinical studies report intergenerational effects on the endogenous opioid system of future progeny following preconception morphine exposure. Given the role of endogenous opioids in energy homeostasis, such effects could impact metabolism in the next generation. Thus, we examined diet-induced modifications in F1 male progeny of morphine-exposed female rats (MORF1). When fed a high fat-sugar diet (FSD) for 6 weeks, MORF1 males display features of emerging metabolic syndrome; they consume more food, gain more weight, and develop fasting-induced hyperglycemia and hyperinsulinemia. In the hypothalamus, proteins involved in energy homeostasis are modified and RNA sequencing revealed down-regulation of genes associated with neuronal plasticity, coupled with up-regulation of genes associated with immune, inflammatory, and metabolic processes that are specific to FSD-maintained MORF1 males. Thus, limited preconception morphine exposure in female rats increases the risk of metabolic syndrome/type 2 diabetes in the next generation

Sitagliptin and Roux-en-Y gastric bypass modulate insulin secretion via regulation of intra-islet PYY.

The gut hormone peptide tyrosine tyrosine (PYY) is critical for maintaining islet integrity and restoring islet function following Roux-en-Y gastric bypass (RYGB). The expression of PYY and its receptors (NPYRs) in islets has been documented but not fully characterized. Modulation of islet PYY by the proteolytic enzyme dipeptidyl peptidase IV (DPP-IV) has not been investigated and the impact of DPP-IV inhibition on islet PYY function remains unexplored. Here we have addressed these gaps and their effects on glucose-stimulated insulin secretion (GSIS). We have also investigated changes in pancreatic PYY in diabetes and following RYGB. Immunohistochemistry and gene expression analysis were used to assess PYY, NPYRs and DPP-IV expression in rodent and human islets. DPP-IV activity inhibition was achieved by sitagliptin. Secretion studies were used to test PYY and the effects of sitagliptin on insulin release, and the involvement of GLP-1. Radioimmunoassays were used to measure hormone content in islets. PYY and DPP-IV localized in different cell types in islets while NPYR expression was confined to the beta-cells. Chronic PYY application enhanced GSIS in rodent and diabetic human islets. DPP-IV inhibition by sitagliptin potentiated GSIS; this was mediated by locally-produced PYY, and not GLP-1. Pancreatic PYY was markedly reduced in diabetes. RYGB strongly increased islet PYY content, but did not lead to full restoration of pancreatic GLP-1 levels. Local regulation of pancreatic PYY, rather than GLP-1, by DPP-IV inhibition or RYGB can directly modulate the insulin secretory response to glucose, indicating a novel role of pancreatic PYY in diabetes and weight-loss surgery