Abstract Chronic Chlamydia pneumoniae infections have been associated with cardiovascular diseases (CVD), but the treatment is difficult. Some drugs used for CVD have been found to have an inhibitory effect on the C. trachomatis infection, which is not considered to be associated with CVD. The purpose of this study was to investigate the effects of heparan sulfate-like glycosaminoglycans, COX inhibitors and rapamycin on the C. pneumoniae infection with cell culture methods. Almost any conceivable factors may affect the results of cell cultures. This study showed the complex interaction between temperature, time and medium during the pre-treatment before inoculation. The influences of these factors on the results overlapped and interlaced. The simple washing procedure could enhance the infectivity of C. pneumoniae although it is generally considered to cause the loss of chlamydial EBs and sequentially decrease the chlamydial infectivity. Although the detailed mechanisms were not studied, the results of this study showed that selective COX inhibitors and rapamycin can inhibit the infectivity of C. pneumoniae by inhibiting the growth and maturation, whereas heparan sulfate-like glycosaminoglycans perhaps inhibit the attachment of C. pneumoniae EBs onto the host cells. Recovery and repassage results showed that the growth can be only delayed by selective COX inhibitors, and it can recover to normal level once the drugs were removed. However, rapamycin inhibited the maturation of chlamydial EBs and therefore the infectivity fell down further even when the rapamycin was removed. This study also presented the variations of pathogenicity between different C. pneumoniae strains in vitro. This study is based on in vitro experiments with an acute infection model. Thus, any definite conclusions on the possible antichlamydial effects of the drugs tested in the treatment of cardiovascular diseases which are associated with chronic C. pneumoniae infections cannot be drawn on the basis of this study.

Prostaglandin (PG) E2 is an eicosanoid derived from the polyunsaturated twenty carbon fatty acid arachidonic acid (AA). PGE2 has physiological as well as pathophysiological functions and is known to be a key mediator of inflammatory responses. Formation of PGE2 is dependent upon the activities of three specific enzymes involved in the AA cascade; phospholipase A2 (PLA2), cyclooxygenase (COX) and PGE synthase (PGEs). Although the research within this field has been intense for decades, the regulatory mechanisms concerning the PGE2 synthesising enzymes are not completely established. PGE2 was investigated in human monocytes with or without lipopolysaccharide (LPS) pre-treatment followed by stimulation with calcium ionophore, opsonised zymosan or phorbol myristate acetate (PMA). Cytosolic PLA2a (cPLA2a) was shown to be pivotal for the mobilization of AA and subsequent formation of PGE2. Although COX-1 was constitutively expressed, monocytes required expression of COX-2 protein in order to convert the mobilized AA into PGH2. The conversion of PGH2 to the final product PGE2 was to a large extent due to the action of microsomal PGEs-1 (mPGEs-1). In addition, experiments with inhibitors of extracellular signal regulated kinase and p38 activation, indicated that phosphorylation of cPLA2α was markedly advantageous for the formation of PGE2. Ellagic acid, a natural polyphenolic compound found in fruits and nuts, was shown to inhibit stimuli induced release of PGE2 in human monocytes. The effect of ellagic acid was not due to a direct effect on the activities of the enzymes but rather to inhibition of the LPS-induced protein expression of COX-2, mPGEs-1 and cPLA2a.

Le cancer de la prostate est le cancer le plus fréquemment diagnostiqué chez l’homme de plus de 50 ans dans les pays industrialisés. L’importance accordée à la qualité de vie des patients conduit la recherche médicale à développer des méthodes de thérapie focale afin de traiter ce type de cancer de manière conservatrice et non plus de manière radicale. Dans cette optique, la photothérapie dynamique (PDT) repose sur l’utilisation de photosensibilisateurs (PS) capables de cibler spécifiquement les cellules cancéreuses et qui, une fois activés par la lumière, vont induire la mort de ces cellules. Sur la base de la chimie verte, le Laboratoire de Chimie des Substances Naturelles (LCSN) de Limoges a développé une stratégie de couplage de la protoporphyrine IX (PpIX), un PS largement étudié, avec des polyamines (PA). Les effets de ces nouveaux PS [la protoporphyrine IX dispermidinée (PpIX-dSd) et la protoporphyrine IX disperminée (PpIX-dSm)] ont été étudiés sur les cellules cancéreuses prostatiques humaines PC-3, DU 145 et LNCaP. Ce travail a permis de démontrer que ces deux PS répondent aux critères attendus d’un PS : une composition pure, une absence de toxicité en absence de lumière et une sélectivité vis-à-vis des cellules tumorales. De plus, ces PS induisent l’apoptose de ces cellules via la voie intrinsèque. Aussi les voies de résistance à l’apoptose ont été étudiées : les PS induisent une inhibition d’Akt, de Bcl-2, de NF-κB et de la voie autophagique et activent la voie p38/COX-2/PGE2 qui ne semble pas être impliquée dans un mécanisme de résistance à l’apoptose dans ce modèle d’étude. Enfin, l’efficacité de ces PS, et notamment de la PpIX-dSd, a été mise en évidence in vivo, à l’aide de xénogreffes sous-cutanées de cellules PC-3 effectuées sur des souris nudes. Ainsi, ces dérivés de PpIX-PA apparaissent comme de bons candidats dans le cadre du traitement du cancer de la prostate par PDT. / Prostate cancer is the most frequently diagnosed cancer among men aged 50 years and older in industrialized countries. Medical research developed methods of focal therapy to treat this type of cancer conservatively and not radically in order to improve the patients quality of life. With this in mind, photodynamic therapy (PDT) is based on the use of photosensitizers (PS) able to specifically target cancer cells and, once activated by light, induce cell death. Based on Green Chemistry, the Laboratoire de Chimie des Substances Naturelles (LCSN) from Limoges developed new PS: protoporphyrin IX, a PS widely studied, vectorized with polyamines (PA). The effects of spermidine-linked protoporphyrin IX (PpIX-dSd) and spermine-linked protoporphyrin IX (PpIX-dSm) were studied on human prostate cancer cells PC-3, DU145 and LNCaP. This study demonstrated that both PS have the expected ideal properties: a pure composition, no toxicity in dark and ability to specifically target tumor cells. Moreover, PpIX-PA induced apoptotic intrinsic pathway. In addition, pathways involved in apoptosis resistance were studied: PS inhibited Bcl-2, Akt, NF-¦ÊB and autophagy but activated p38/COX-2/PGE2 pathway which was not involved in apoptosis resistance in our model. Finally, in vivo experiments showed PpIX-PA efficiency using subcutaneous xenograft of PC-3 cells performed on nude mice. Thus, these derivatives of PpIX-PA appear to be good candidates in prostate cancer treatment by PDT.

No description available.

Cyclooxygenase-2 (COX-2) is a prostaglandin-generating enzyme that exhibits low basal expression levels and is upregulated in the central nervous system (CNS) in response to inflammatory stimuli. COX-2 has been implicated in the microglial-mediated neuroinflammatory and neurodegenerative processes of multiple sclerosis (MS), a demyelinating autoimmune disease. To study COX-2 activity and the role it may play in demyelination, a novel PET radiotracer specific for COX-2, [11C]BRD1158, was developed and evaluated in the lysolecithin rodent model of focal demyelination with PET-MR imaging. Preliminary results of this pilot pre-clinical study confirmed our hypothesis that the properties of [11C]BRD1158 enable visualization and monitoring of COX-2 activity under pathological conditions induced by LPC. Radiotracer uptake correlated positively with disease progression at the site of LPC injection in male rats, peaking at day 7 and resolving by day 28. Treatment with an FDA-approved MS therapy, Siponimod, diminished the increase in COX-2 activity and tracer uptake at the lesion site and throughout the brain in both male and female rats. The results from the present study will inform future pre-clinical and translational work that validates the use of [11C]BRD1158 to image COX-2 activity as a marker of underlying inflammation in MS, leading to a better understanding of pathological and inflammatory processes in MS development and progression.

Obesity is a disease that increases risk of developing metabolic diseases including insulin resistance (IR), metabolic syndrome (MS), and type 2 diabetes (T2D). Adipose tissue expansion during obesity leads to immune cell infiltration, causing local inflammation and disruption of lipid homeostasis. There is an association between exposure to environmental chemicals, like p,p’-DDE, a metabolite of p,p’-DDT, and diagnosis of obesity, dyslipidemia, IR, and prevalence of MS and T2D. DDE accumulates in fatty tissues and has been shown to have immunomodulatory properties, affecting macrophage and T cell populations. Potential mechanisms were studied by which DDE could modulate adipocyte and immune cell function and facilitate an increased risk of obesity and immune dysregulation, potentially through cyclooxygenase-2 (COX-2). 3T3-L1 preadipocytes and J774A.1 macrophages were studied for the effects of DDE on adipogenesis and macrophage reactivity, respectively. 3T3-L1 cells were induced to differentiate to adipocytes using a sub-optimal differentiation cocktail with increasing concentrations of DDE (0.5uM-100uM). It was determined that DDE enhanced adipogenesis in a concentration dependent manner and the expression of adipogenic and lipogenic genes, indicating that DDE enhances adipogenesis. In J774A.1 cells, the ability of DDE or 10uM NS-398, a specific COX-2 inhibitor, to inhibit the production of the prostaglandins PGE2, PGD2, PGF2a, was assessed in vitro and in a cellree system. DDE or NS-398 followed by immune challenge reduced cellular PG secretion and reduced PG production in a cell free system, indicating that DDE may interfere with lipid mediator signaling. Additionally, DDE or NS-398 exposure altered gene expression in J774A.1 cells following M1 or M2 polarization stimulus. Lastly, male C57Bl mice were exposed to 2mg/kg DDE for 5 days and the macrophage population of the adipose stromal vascular fraction was analyzed by flow cytometry. Adipose from DDE treated animals contained approximately 40% F4/80+CD11b+ macrophages. These results indicate that DDE may alter the homeostasis of adipose tissue by both enhancing adipogenesis and altering the reactivity of the resident macrophage population in a manner that may contribute to adipose dysfunction. These data suggest a possible mechanism by which DDE exposure may contribute to adiposity and adipose tissue dysfunction commonly seen in metabolic disease.

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No description available.

No description available.

No / Erythema occurs in human skin following excessive exposure to ultraviolet radiation (UVR), and this is in part mediated by the vasodilator prostaglandin E2 (PGE2). While keratinocytes are a major source of this pro-inflammatory eicosanoid, epidermal melanocytes (EM) also express some of the cellular machinery required for PGE2 production. The primary aim of this study is to determine whether EM can produce PGE2 and so potentially also contribute to UVR-induced skin inflammation. Furthermore, we investigate the likely pathway by which this PGE2 production is achieved and investigate whether PGE2 production by EM is correlated with melanogenic capacity. Primary cultures of EM were established from nine normal healthy individuals with skin phototype-1 (n=4) and 4 (n=5), and PGE2 production and melanogenic status were assessed. EM produced PGE2 under baseline conditions and this was increased further upon stimulation with arachidonic acid. Moreover, EM expressed cytoplasmic phospholipase A2, cyclooxygenase-1 and cytoplasmic prostaglandin E synthase. However, no EM culture expressed cyclooxygenase-2 under baseline conditions or following arachidonic acid, UVB- or H2O2 treatments. PGE2 production in response to UVB was highly variable in EM cultures derived from different donors but when pooled for skin phototype exhibited a positive correlation only with SPT-1 derived EM. Interestingly, PGE2 production by EM in response to UVB showed no correlation with baseline levels of melanin, tyrosinase expression/activity or tyrosinase-related protein-1 expression. However, there was an apparent negative correlation with baseline expression of dopachrome tautomerase (DCT), a melanogenic enzyme with reported anti-oxidant potential. These findings suggest that EM have the potential to contribute to UVR-induced erythema via PGE2 production, but that this response may be more related to oxidative stress than to their melanogenesis status. / The Wellcome Trust