Problemas reprodutivos ocorrem no hipo e no hipertireoidismo, mas pouco se conhece a respeito das bases moleculares destas alterações. Avaliou-se o efeito da administração de triiodotironina na atividade do gonadotrofo em ratos Wistar tireoidectomizados. O hipotireoidismo ocasionou elevação no TSH e do LH sérico, aumento do conteúdo do mRNA e redução do conteúdo protéico do LH e do FSH, redução da cauda poli (A), redução da testosterona e do FSH séricos, redução da expressão do receptor de LH, aumento da expressão do receptor de andrógenos testiculares e epididimais. O tratamento com T3 acarretou a diminuição do mRNA e aumento do conteúdo protéico de LH, aumento do FSH sérico, diminuição do conteúdo do mRNA e aumento do conteúdo protéico do FSH, aumento da expressão do receptor de LH, redução da expressão de receptores de andrógenos testiculares e epididimais. Esses resultados sugerem que o T3 age na modulação da função do gonadotrofo e na modulação da expressão dos receptores em tecidos-alvo. / Reproductive disorders occur in hypo and hyperthyroidism, but little is known about the molecular basis of these alterations. The effect of administration of triiodothyronine (T3) on the activity of gonadotropes in thyroidectomyzed male Wistar rats was evaluated. Hypothyroidism caused increased on TSH and LH serum concentrations, increased of mRNA content and decreased in protein content of LH and FSH, reduction in the length of poli(A) tail of LH, reduction in testosterone and FSH serum concentrations, reduction in the expression of LH receptor, increased in the expression of androgen receptors in the testis and epididymis. T3 treatment caused reduction on mRNA and increased on mRNA of LH and FSH, increased serum FSH, increased the expression of LH receptor, and reduction of the expression of androgen receptors in the testis and epididymis. These results suggest that T3 modulates the function of gonadotrope and the expression of the receptors in target-tissues.

Os gliomas são tumores do sistema nervoso central (SNC) que evoluem a partir das células da glia. O tipo mais frequente e mais agressivo destes tumores é conhecido como glioblastoma multiforme (GBM) e entre as características biológicas de agressividade associadas a esse tumor estão o seu rápido crescimento e ausência de apoptose. O seu prognóstico desfavorável está associado à dificuldade de tratamento dessas células, pois possuem resistência à quimioterapia e a radioterapia. A expressão gênica das enzimas ciclooxigenase-1 (COX-1), ciclooxigenase-2 (COX-2), prostaglandina E sintase-1 microssomal (mPGES-1), prostaglandina E sintase-2 microssomal (mPGES-2), prostaglandina E sintase citosólica (cPGES) e os produtos da síntese destas enzimas, incluindo a prostaglandina E1 (PGE1) e a prostaglandina E2 (PGE2) estão diretamente relacionados com a malignidade dos gliomas. A PGE1 e a PGE2 podem atuar de modo autócrino e parácrino, interagindo com suas células alvos através de ligação aos receptores da superfície celular que estão ligados a proteína G. Estes receptores são conhecidos como receptores EPs e dividem-se em quatro subtipos: EP-1, EP-2, EP-3 e EP-4 sendo que cada um deles ativa vias distintas de sinalização intracelular. Desta forma, este estudo teve por objetivo analisar in vitro o papel da PGE1, PGE2 e seus receptores na proliferação e apoptose em glioma humano, e a expressão das enzimas COX-1, COX-2, mPGES-1, mPGES-2 e cPGES. / Gliomas are tumors of the central nervous system (CNS) that evolve from glial cells. The most common and most aggressive form of these tumors is known as glioblastoma multiforme (GBM). The biological aggressiveness of GBM is associated with its rapid growth and lack of apoptosis. Its poor prognosis is strongly associated with the difficulty of treating these cells as they are resistant to chemotherapy and radiotherapy. The gene expression of the enzymes cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1), microsomal prostaglandin E synthase-2 (mPGES-2), cytosolic prostaglandin E synthase (cPGES) and the products of the activity of these enzymes, including prostaglandin E1 (PGE1) and prostaglandin E2 (PGE2), are directly related to the malignancy of gliomas. PGE1 and PGE2 can act in an autocrine and paracrine manner, by interacting with their target cells via binding to cell surface receptors that are linked to G-proteins. These receptors are known as EP receptors and are divided into four subtypes: EP1, EP2, EP3 and EP4; each of which activates distinct intracellular signaling pathways. Therefore, this study aimed to analyze, in vitro, the role of PGE1, PGE2 and their receptors in the proliferation and apoptosis of human glioma and the expression of COX-1, COX-2, mPGES-1, mPGES-2 and cPGES.

[ES] La lesión por isquemia-reperfusión (I/R) hepática (IRI) es una causa importante de mortalidad y morbilidad en la resección hepática y el trasplante de hígado. Durante la hipoxia, el hígado permanece sin oxígeno, cambiando su metabolismo y parando la síntesis de ATP. Paradójicamente, el restablecimiento del flujo de oxígeno causa más daño, activando el sistema inmunitario que generará una gran cantidad de especies reactivas de oxígeno (ROS) causando daño celular y tisular. La ciclooxigenasa-2 (COX-2) es una enzima clave en la biosíntesis de prostaglandinas y su importancia en la IRI es controvertida. La PGE2, prostaglandina E2, es el principal producto de la COX-2, y participa en la mediación de procesos patológicos como la inflamación, la fiebre y el dolor. El uso de AINEs, inhibidores específicos de la COX, apunta a un efecto beneficioso en la resolución del proceso inflamatorio, pero cada vez más estudios apoyan el papel antiinflamatorio de la COX-2. De hecho, estudios previos han demostrado que la sobreexpresión de COX-2 en hepatocitos protege a los ratones de la apoptosis y el estrés celular, además de reducir la respuesta inflamatoria en diferentes modelos de enfermedad hepática. En esta tesis doctoral, se utilizó un ratón transgénico que sobreexpresa COX-2 en los hepatocitos (h-COX-2 Tg) para dilucidar el papel y la implicación de la COX-2 en la IRI. Los animales de tipo silvestre (Wt) y h-COX-2 Tg fueron sometidos a 90 min de isquemia, seguidos de 4 o 24 h de reperfusión. Comparando los animales h-COX-2 Tg con sus hermanos Wt, el daño celular y tisular se atenúa tras la IRI. Entre las distintas vías modificadas, la cascada inflamatoria está menos activada, con menor liberación de citoquinas pro-inflamatorias, menor reclutamiento hepático, e infiltración de neutrófilos. Las vías de necrosis y apoptosis también se atenúan así como se reduce del estrés del retículo endoplásmico, y aumenta la autofagia. La respuesta antioxidante se potencia en el contexto de la sobreexpresión de COX-2 y la producción total de ROS es menor, lo que contribuye a un menor daño tisular. Cuando los animales Wt se someten un pre-condicionamiento (PC), la COX-2 endógena se induce a niveles más altos que sin PC, mostrando menos daño, una inflamación atenuada, y una respuesta antioxidante mejorada. Además, se muestra que el papel de la COX-2 en esta protección es específico, ya que su inhibición con DFU revierte los efectos observados e iguala el daño causado a los animales Wt. Las mitocondrias son actores centrales en la fisiopatología de la IRI. En este sentido, la función mitocondrial está preservada en los hígados que sobreexpresan COX-2, con un potencial de membrana mitocondrial conservado y una tasa respiratoria preservada. Estos efectos pueden explicarse por una estabilización de las crestas mitocondriales, invaginaciones de la membrana mitocondrial interna (IMM) que se mantienen mediante interacciones de varias isoformas de la proteína OPA1. Su procesamiento está mediado por proteasas, como OMA1. En ratones h-COX-2 Tg hay un menor procesamiento de OPA1, que se correlaciona con una actividad atenuada de OMA1. Por otro lado, se realizó un estudio retrospectivo en pacientes que habían sido sometidos a un trasplante hepático. Se analizaron los niveles de PGE2 y se correlacionaron con las funciones hepáticas tras el trasplante. Este análisis muestra que la presencia de PGE2 en el plasma de los pacientes receptores se correlaciona con un mejor pronóstico, mientras que unos niveles más bajos de PGE2 se asocian con una disfunción precoz del injerto. Todos estos resultados presentan a la COX-2 como un nuevo actor en la protección del hígado tras I/R, mostrando un papel antiinflamatorio y antioxidante, así como reduciendo el daño mitocondrial, el estrés celular y la muerte celular. Además, se demuestra cómo las prostaglandinas derivadas de la COX-2 en condiciones fisiológicas pueden desempeñar un papel protector en casos de trasplante hepático. / [CA] La lesió per isquèmia-reperfusió (I/R) hepàtica (IRI) és una causa important de mortalitat i morbiditat en la resecció hepàtica i el trasplantament de fetge. Durant la hipòxia, el fetge roman sense oxigen, canviant el seu metabolisme i aturant la síntesi d'ATP. Paradoxalment, el restabliment del flux d'oxigen causa més danys, activant el sistema immunitari que genera una gran quantitat d'espècies reactives d'oxigen (ROS) causant dany cel·lular i tissular. La ciclooxigenasa-2 (COX-2) és un enzim clau en la biosíntesi de prostaglandines i la seva importància a l'IRI és controvertida. La PGE2, prostaglandina E2, és el principal producte de la COX-2, i participa en la mediació de processos patològics com la inflamació i la febre. Mentre que l'ús d'AINEs, inhibidors específics de la COX-2, apunta a un efecte beneficiós en la resolució del procés inflamatori, cada cop més estudis donen suport a un paper antiinflamatori de la COX-2. De fet, estudis previs han demostrat que la sobreexpressió de COX-2 en hepatòcits protegeix els ratolins de l'apoptosi i l'estrès cel·lular, a més de reduir la resposta inflamatòria, en diferents models de malaltia hepàtica. En aquesta tesi, s'ha utilitzat un ratolí transgènic que sobreexpressa la COX-2 en els hepatòcits (h-COX-2 Tg) per dilucidar el paper i la implicació de la COX-2 a l'IRI. Els animals de tipus silvestre (Wt) i h-COX-2 Tg van ser sotmesos a 90 min d'isquèmia, seguits de 4 o 24 h de reperfusió. Comparant els animals h-COX-2 Tg amb els seus germans Wt, el dany cel·lular i tissular s'atenua després de l'IRI. Entre les diferents vies modificades, la cascada inflamatòria està menys activada, s'alliberen menys citocines proinflamatòries , hi ha un menor reclutament hepàtic i menor infiltració de neutròfils. Les vies de necrosi i apoptosi també s'atenuen, així com es redueix l'estrès del reticle endoplasmàtic, i l'autofàgia augmenta. La resposta antioxidant es potencia i la producció total de ROS també és menor, fet que contribueix a un menor dany tissular. Quan els animals Wt se sotmeten a un precondicionament (PC), la COX-2 endògena s'indueix a nivells més alts que sense PC, i aquests fetges mostren menys dany, una inflamació atenuada i una resposta antioxidant millorada. A més, es mostra que el paper de la COX-2 en aquesta protecció és específic, ja que la seva inhibició amb DFU, reverteix els efectes observats i iguala el dany causat als animals Wt. Els mitocondris són actors centrals en la fisiopatologia de l'IRI. En aquest sentit, la funció mitocondrial és preservada als fetges que sobreexpressen COX-2, com es pot demostrar per un potencial de membrana mitocondrial conservat i una taxa respiratòria preservada. Aquests efectes es poden explicar per una estabilització de les crestes mitocondrials, invaginacions de la membrana mitocondrial interna (IMM) que es mantenen mitjançant interaccions de diverses isoformes d'OPA1, una proteïna de la IMM. El seu processament està mediat per proteasas, com OMA1. En ratolins h-COX-2 Tg hi ha un menor processament d'OPA1, que es correlaciona amb una activitat atenuada d'OMA1, mostrant una estabilització de les crestes. D'altra banda, es va fer un estudi retrospectiu amb pacients que havien estat sotmesos a un trasplantament hepàtic. Es van analitzar els nivells de PGE2 i es van correlacionar amb les funcions hepàtiques després del trasplantament. Aquesta anàlisi mostra que la presència de PGE2 en el plasma dels pacients receptors es correlaciona amb un millor pronòstic, mentre que uns nivells més baixos de PGE2 s'associen amb una disfunció precoç de l'empelt. Tots aquests resultats presenten a la COX-2 com un nou actor en la protecció del fetge després d'I/R, mostrant un paper antiinflamatori i antioxidant, així com reduint la lesió mitocondrial, l'estrès cel·lular i la mort cel·lular. A més, es demostra com les prostaglandines derivades de la COX-2 en condicions fisiològiques poden exercir un paper protector en casos de trasplantament hepàtic. / [EN] Hepatic ischemia-reperfusion (I/R) injury (IRI) is a major cause of mortality and morbidity in liver resection and liver transplantation. During the hypoxia, the liver remains without oxygen supply, shifting its metabolism and stopping the ATP synthesis. Paradoxically, the restoration of oxygen flow causes the most damage with an activation of the immune system that will generate a burst of reactive species of oxygen (ROS) that will cause cell and tissue damage. Cyclooxygenase-2 (COX-2) is a key enzyme in prostaglandin biosynthesis and its importance in IRI is controversial. PGE2, prostaglandin E2, is the main product of COX-2, and is mainly involved in mediating pathological processes such as inflammation, fever and pain. While the use of NSAIDs, specific COX inhibitors, points to a beneficial effect in the resolution of the inflammatory process, several studies support the idea of an anti-inflammatory role of COX-2. In fact, previous studies have shown that COX-2 overexpression in hepatocytes protects mice from apoptosis and cellular stress, as well as reducing the inflammatory response, in different liver disease models. In this PhD thesis, a hepatocyte-specific COX-2 transgenic mouse (h-COX-2 Tg) was used to elucidate the role and involvement of COX-2 in IRI. Wild type (Wt) and h-COX-2 Tg animals were subjected to 90 min of ischemia, followed by 4 or 24 h of reperfusion. Comparing h-COX-2 Tg animals with their Wt littermates, cellular and tissue damage resulting from IRI is attenuated. Among these pathways, the inflammatory cascade is less activated, with less pro-inflammatory cytokine release, less hepatic recruitment and neutrophil infiltration. Necrosis and apoptosis pathways are also attenuated such as reduced endoplasmic reticulum stress, and increased autophagy. The antioxidant response appears to be enhanced in the context of COX-2 overexpression and total ROS production is also lower, contributing to less tissue damage. When Wt animals are subjected to preconditioning (PC), endogenous COX-2 is induced at higher levels than without PC, and these livers show less damage, attenuated inflammation, and an enhanced antioxidant response. Furthermore, the role of COX-2 in this observed protection has been shown to be specific, as its inhibition with DFU, reverses the observed effects, and matched the damage caused to Wt animals. Mitochondria are central players in the pathophysiology of IRI. In this regard, mitochondrial function is preserved in COX-2-overexpressing livers, as can be demonstrated by a conserved mitochondrial membrane potential and a preserved respiratory rate. These results can be explained by a stabilisation of mitochondrial cristae, invaginations of the inner mitochondrial membrane (IMM) that maintained through interactions of various isoforms of OPA1. Its processing is mediated by proteases, such as OMA1, which acts under certain stimuli. In h-COX-2 Tg mice, there is a reduced OPA1 processing that correlates with attenuated OMA1 activity, showing a stabilisation of cristae in the context of COX-2 overexpression after I/R. On the other hand, a retrospective study was conducted in patients who had undergone liver transplantation. In this part of the study, PGE2 levels were analysed and correlated with liver functions after transplantation. This analysis shows that the presence of PGE2 in the plasma of recipients correlates with a better prognosis, while lower PGE2 levels are associated with early graft dysfunction. All these results present COX-2 as a new player in liver protection after I/R, showing an anti-inflammatory and antioxidant role, as well as reducing mitochondrial damage, cell stress and cell death. Furthermore, it is shown how COX-2-derived prostaglandins under physiological conditions can play a protective role in cases of liver transplant. / This work has been carried out with the financial support of the Spanish Ministry of Science and Innovation (SAF2016-75004R and PID2019-108977RB-100), the CIBERehd (Centro de Investigaciones Biomédicas En Red de Enfermedades Hepáticas y Digestivas) and the COST Action (CA15203 - Mitochondrial mapping: Evolution - Age - Gender - Lifestyle - Environment (MITOEAGLE)). Marina Fuertes Agudo benefited from a pre-doctoral FPI contract (BES-2017- 081928) associated with the SAF2016-75004R project. She spent 3 months in the laboratory of Dr. Pau Sancho Bru at the Institut d’Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS, Barcelona, Spain) funded by a short stay grant awarded by the CIBERehd and 3 months in the laboratory of Dr. Anne Dubart Kupperschmitt and Dr. Jean Charles Duclos Vallée at the Institut Nationale de la Santé et la Recherche Médicale (INSERM, Villejuif, France) funded by a short stay grant awarded by the European Molecular Biology Organisation (EMBO, SEG_9771). / Fuertes Agudo, M. (2023). Role of cyclooxygenase-2 in ischemia-reperfusion injury in the liver [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/196602

Antimicrobial peptides (AMPs) are ubiquitous and display broad-spectrum antimicrobial activity that can control bacterial colonization of surfaces. Ceragenins are small-molecule mimics of AMPs and have several advantages over AMPs, including cost of manufacture and stability. A ceragenin, CSA-120, modified with an acrylamide group was directly incorporated into fluoropolymer coatings as a means of inhibiting bacterial biofilm formation. The ceragenin-containing coatings displayed improved performance. By conjugating a copper chelating group to the ceragenin, chelation of 64Cu by the conjugate was effective and provided a stable complex that allowed in vivo imaging. This conjugate may provide a means of identifying infection sites in patients presenting general signs of infection without localized symptoms. A combination nanoparticle comprised of a maghemite core for enhanced T2 MRI contrast diagnostics, a colloidal silver shell acting as an antimicrobial and therapeutic vehicle, and a ceragenin (CSA- 124) surfactant providing microbial adhesion was synthesized and characterized by multiple methods. Silver nanoparticles conjugated with ceragenin, CSA-124, as a potential Gram-positiveselective antimicrobial were synthesized and termed as CSA-SNPs. Herein, CSA-SNPs are characterized using multiple methods and the antimicrobial properties are determined through minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) and time-kill study. Prostanoids are a natural subclass of eicosanoids generated mainly from metabolic oxidation of arachidonic acid. Cyclopentenone prostaglandins (cyPGs) contain a highly reactive α,β-unsaturated carbonyl group in their cyclopentenone ring and possess three main potentially therapeutic properties: anti-inflammatory, antiproliferative and antiviral. We designed and synthesized EC and its derivatives in reducing secretion of pro-inflammatory cytokines IL-6 and IL-12. Mucosal-Associated Invariant T (MAIT) Cells are unique innate-like T cells and play a key role in host defense against bacterial and fungal infection as well as in human autoimmune diseases. The MAIT cells are activated through T-cell receptor αβ chain (TCR-αβ) binding with the MR1-ligand, which is vitamin B metabolites presented on MR1. Rribityllumazines, one of important MR1-ligand was synthesized in my study.

No description available.

The oxidation of simple benzene derivatives by a mutant of Pseudomonas putida, called 39-D, produces cis-arenediols (1). The diols are enantiomerically pure and can be used as synthons for the preparation of a variety of interesting compounds because of their stereochemistry and the special array of functional groups. See: Figure 1 cis -Toluenedio] (2) served as a chiral intermediate in an efficient synthesis of enone (3). which has been used to attain prostaglandin Fra and Neplanocin A. The same diol (2) was transformed into both enantiomers of a terpene synthon (4). See: Figures 2, 3, 4 Oxidative functionalization of cis-chlorobenzenediol (5) afforded intermediates suitable for transformation into L-erythrose (6), conduritol C (7), dihydroconduritol C (8) and aminoconduntol F-4 (9). See: Figures 5, 6, 7, 8 The application of this versatile synthetic protocol culminated in an approach to kifunensine (10), an important glycosidase inhibitor, which was approached according to the following retrosynthetic analysis: See: Figures 10, 11, 12, 5, 14, 13 A detailed study of the nucleophilic opening of epoxide 13 was carried out in order to better understand the parameters of the diastereoselective functionalization of arenediols. Details are provided for the oxidative functionalization of chlorobenzenediol (5), the key compound in all of the projects discussed. / Ph. D.

No / Prostanoids modulate the activity of human pregnant myometrium and their functional role can be appreciated through characterisation of prostanoid receptors and tissue concentration of prostanoids. We have applied a lipidomic approach to elucidate the profile of prostanoids in human non-labouring and labouring myometrium. We have identified a total of nineteen prostanoids including prostacyclin, thromboxanes, prostaglandins and dihydro-prostaglandins. Prostacyclin was the predominant prostanoid in both non-labouring and labouring myometria, with PGD2 and PGF2¿ being the second most abundant. Although the total amount of prostanoids was increased in the labouring tissue, PGE2 and 13,14-dihydro-15-keto-PGE2 were the only prostanoids to increase significantly at early and late labour (p¿0.001). Our data suggest that PGF2¿ plays an important role in parturition, whilst the increase in PGE2 could occur to facilitate cervical dilation and relaxation of the lower myometrium during labour. Although the elevation in TXA2 was less marked than expected, in terms of translation to function even a relatively small increase in the level of this potent spasmogen may have significant effects.

<p>The kidney regulates the excretion of water and electrolytes, which maintains homeostasis and enables control of arterial blood pressure. Hyaluronan, a large negatively charged interstitial glucosaminoglycan, is heterogeneously distributed within the kidney, primarily found in the medulla.</p><p>Medullary hyaluronan content changes depending on the state of body hydration and plays a part in fluid regulation through its water binding and viscoelastic properties. </p><p>The aim of this thesis was to provide new insight into the regulation of intrarenal hyaluronan during different states of body hydration, during completion of kidney development, and during diabetes mellitus.</p><p>Dehydration reduces medullary interstitial hyaluronan in parallel with reduced hyaluronan synthase 2 gene expression and increased urinary hyaluronidase activity. Acute hydration results in an increase in medullary hyaluronan, an increase that requires nitric oxide and prostaglandins. Urinary hyaluronidase activity decreases during hydration. The elevation of hyaluronan is important for reducing water permeability of the interstitium i.e. favoring diuresis.</p><p>Changes in hyaluronan concentration constitute a morphoregulatory pathway that plays a key role in nephrogenesis. The reduction in neonatal hyaluronan depended on an angiotensin II mediated process that does not appear dependent on lymph vessel formation. If angiotensin II is blocked with an ACE inhibitor, hyaluronan accumulates, which results in structural and functional abnormalities in the kidney. </p><p>Renomedullary hyaluronan is elevated during uncontrolled diabetes, which coincides with induction of hyaluronan synthase 2 mRNA, hyperglycemia, glucosuria, proteinuria and overt diuresis. The levels of hyaluronan are probably at a <i>terminus ad quem</i> as no further response was seen during hydration. The higher interstitial expression of hyaluronan during diabetes may be involved in the progression of diabetic nephropathy.</p><p>This thesis in physiology provides new mechanistic insights into the regulation of renal hyaluronan during various aspects of fluid handling.</p>

Le rejet chronique se manifeste dans le poumon par la bronchiolite oblitérante (BO), une pathologie inflammatoire et fibrotique menant à l’oblitération des bronchioles. L’étiologie exacte de cette maladie demeure inconnue. Certaines études suggèrent qu'un déséquilibre des leucotriènes (LT) sur les prostaglandines (PG) favorise la fibrose pulmonaire. Les taux des LT et des PG dans le poumon humain post-transplantation sont inconnus. Nous proposons qu'un déséquilibre de cystéinyl leucotriènes (CysLT) sur la PGE2 existe dans le poumon transplanté et pourrait être impliqué dans la pathogenèse de la BO. Aussi, les leucotriènes contribueraient à la fibrose par la transition épithélio-mésenchymateuse (TEM). Afin de vérifier ces hypothèses, nous avons déterminé les taux de CysLT et de PGE2 dans le liquide de lavage broncho-alvéolaire (LBA) provenant de poumons transplantés chez l'homme ainsi que leurs corrélations cliniques. Nous avons également déterminé la capacité des CysLT à induire l’expression des marqueurs de la TEM in vitro. Nous avons découvert des taux de CysLT et PGE2 supérieurs à la normale dans les LBA des greffés. Un pic prédominant de CysLT sur PGE2 est observée à 52 semaines postgreffe et deux facteurs de risque de la BO, les infections au CMV et à l’Aspergillus, sont associés au ratio CysLT/PGE2> 1. In vitro, les CysLT induisent une répression des marqueurs épithéliaux mais n’induisent pas l’expression de marqueurs mésenchymateux chez les cellules épithéliales bronchiolaires. / Chronic rejection occurs, in the lung, in the form of bronchiolitis obliterans (BO), an inflammatory and fibroproliferative disease that leads to the obliteration of the bronchioles. A concept of the pathogenesis of BO has been suggested and several risk factors are associated to it, however, the exact etiology of this disease remains unknown. Studies have suggested that an imbalance of leukotrienes (LT) over prostaglandins (PG) promotes pulmonary fibrosis. The levels of LT and PG in the human lung post-transplantation are unknown. We propose that an imbalance of cysteinyl leukotrienes (CysLT) on PGE2 exists in the transplanted lung and may be implicated in the pathogenesis of BO. We also suggest that leukotrienes contribute to fibrosis through epithelial-mesenchymal transition (EMT). In order to test these hypotheses, we have determined the levels of CysLTs and PGE2 in human transplanted lung bronchoalveolar lavage fluid (BALf) samples and their clinical correlations. We have also determined the capacity of CysLT to induce the expression of EMT markers in vitro. We found high average levels of CysLT and PGE2 in the BAL of transplant patients. A predominant peak of CysLT over PGE2 was observed at 52 weeks post-transplantation and two risk factors for BO, CMV infections and Aspergillus were associated with CysLT/PGE2 ratio> 1. According to our experimental parameters, CysLT can induce the repression of epithelial markers but do not induce the expression of mesenchymal markers in vitro in small airway epithelial cells.

Prostanoids are oxygenated derivatives of arachidonic acid with a wide range of physiological effects in vertebrates including modulation of inflammation and innate immune responses. Nonsteroidal anti-inflammatory drugs (NSAIDs) act through inhibition of cyclooxygenase (COX) conversion of arachidonic acid to prostanoids. In order to better understand the potential of environmental NSAIDS for interruption of normal levels COX products in fishes, we developed an LC/MS/MS-based approach for tissue analysis of 7 prostanoids. Initial studies examining muscle, gut and gill demonstrated that prostaglandin E2 (PGE2) was the most abundant of the measured prostanoids in all tissues and that gill tissue had the highest and most consistent concentrations of PGE2. After short-term 48-h laboratory exposures to concentrations of 5, 25, 50 and 100 ppb ibuprofen, 50.0ppb and 100.0 ppb exposure concentrations resulted in significant reduction of gill tissue PGE2 concentration by approximately 30% and 80% respectively. The lower exposures did not result in significant reductions when compared to unexposed controls. Measured tissue concentrations of ibuprofen indicated that this NSAID had little potential for bioaccumulation (BCF 1.3) and the IC50 of ibuprofen for inhibition of PGE2 production in gill tissue was calculated to be 0.4 µM. Short-term laboratory exposure to ibuprofen did not result in significant alteration of concentrations of PGE2 at environmentally relevant concentrations.