La Dégénérescence Maculaire Liée à l’Age (DMLA) est la première cause de cécité légale dans les pays industrialisés chez les personnes âgées. L’atrophie géographique – l’une des formes tardives de la DMLA - est caractérisée par la perte de l’épithélium pigmentaire et la dégénérescence des photorécepteurs. Nous groupe a montré précédemment que dans l’atrophie géographique, les phagocytes mononucléés (PMs) s’accumulent dans l’espace sous-rétinien, et induisent la dégénérescence rétinienne via la production d’IL-1β. Dans un premier temps, nous montrons que la présence de PMs sous-rétiniens est associée à la perte des bâtonnets et la dégénérescence des segments de cônes dans la zone de transition de patients atrophiques. Nous montrons ensuite dans différents modèles in vivo et ex vivo que les macrophages récapitulent ces effets, et qu’IL-1β est nécessaire à la perte des segments externes des cônes induite par les PMs. Dans un deuxième temps, nos résultats montrent qu’IL-1β induit indirectement la mort des bâtonnets, en perturbant l’homéostasie rétinienne du glutamate. L’inhibition des récepteurs glutamatergiques pour prévenir l’excitotoxicité du glutamate, ou la supplémentation en cystine favorisant la restauration de la machinerie neuronale antioxydante, permettent de protéger les bâtonnets de la toxicité induite par IL-1β. L’ensemble de nos résultats démontre le rôle joué par IL-1β dans la dégénérescence des segments de cônes et la perte des bâtonnets dans l’inflammation sous-rétinienne. Cette étude permettra la mise au point de thérapies innovantes, afin de lutter contre la forme atrophique de la DMLA, pour laquelle il n’existe actuellement aucun traitement. / In geographic atrophy (GA), one of the late forms of Age-related Macular Degeneration (AMD), an extending atrophic zone forms, characterized by the loss of retinal pigment epithelium and photoreceptor degeneration. Subretinal mononuclear phagocytes (MPs) accumulate in GA, and are associated with IL-1β-dependent retinal degeneration. First, we confirmed that subretinal accumulation of MPs is associated with rod degeneration and cone segment loss in the transitional zone in GA human samples. Using ex vivo and in vivo models, we then demonstrated that MPs-derived IL-1β leads to severe cone segment degeneration. Therefore, inhibiting subretinal MP accumulation or IL-1β might protect the cone segment, and help preserve high acuity daytime vision in conditions characterized by subretinal inflammation. Second, we showed that IL-1β effect on rod degeneration is indirect, and mediated by glutamate. Our results indicate that IL-1β impairs Müller glial cells glutamate recycling, and subsequently leads to the extracellular increase in glutamate content. Inhibiting glutamate receptors to prevent excitotoxicity, or exogenous cystine supplementation to supply antioxidant metabolism, are sufficient to protect rods from IL-1β-induced neurotoxicity. Our results provide new perspectives to treat pathologies associated with subretinal inflammation such as late AMD. Our results collectively demonstrated that MP-derived IL-1β induces cone segment loss, and glutamate homeostasis disruption associated with rod degeneration. This study will help with the development of new therapeutic strategies in dealing with inflammatory retinal pathologies as geographic atrophy.

Dans la première partie de ma thèse, nous avons étudié le rôle de la TSLP, une cytokine produite par les kératinocytes, dans la mélanogenèse. Nous avons montré que l'expression de TSLP était induite dans l'épiderme de la peau atteinte de mélanome chez la souris et l'humain. Notre resulats indiquent que la TSLP murine joue un rôle dans la croissance de la tumeur et que ce rôle s'exerçait via les cellules immunitaires. Nos résultats suggèrent l'existence d'un dialogue entre les cellules du mélanome, les kératinocytes et les cellules immunitaires jouant un rôle important dans la croissance et la métastase du mélanome. Dans la seconde partie, nous avons exploré les cytokines produites dans le contexte de la dermatite atopique et leur rôle dans l'initiation de l'asthme. Nous avons trouvé que TSLP est différemment impliquée dans la sensibilisation allergique épicutanée et dermocutanée, et nous avons identifiée l'IL-1β comme un acteur majeur dans la marche atopique. Cette étude expose de nouvelles approches pour le développement de stratégies pour prévenir ou stopper la marche atopique. / My PhD thesis aimed at studying skin inflammatory responses under two pathogenic contexts, melanoma and atopic march. In the first part, we studied the role of keratinocyte-produced cytokine TSLP in melanomagenesis. We showed that TSLP expression was induced in skin epidermis of both mouse and human melanoma. We further provided evidence that TSLP played a tumor-promoting role by ablating or overexpressing TSLP in mouse melanoma, and that such role of TSLP was mediated through immune cells. Our results suggest that a crosstalk between melanoma cells, epidermal keratinocytes and immune cells plays an important role for melanoma growth and metastasis. In the second part, we explored the cytokine factors derived from atopic dermatitis (AD) in driving the asthma. By using an innovative laser-assistant microporation system, we established novel atopic march mouse models. We found that TSLP was differentially implicated in allergen epicutaneous or dermacutaneous sensitization, and further identified IL-1β as an important player in atopic march. This study adds new insight into the development of potential strategies for preventing or stopping the atopic march.

The cytokines GM-CSF, IL-3 and IL-5 are central regulators of haemopoietic cell functions and are pivotal in the regulation of haemopoiesis and inflammatory responses of myeloid cells. In particular, these cytokines have been shown to perform essential functions in host defence against foreign pathogens through their ability to regulate innate immune responses in myeloid cells. As key regulators of such important processes, these cytokines play an important role in human inflammatory pathologies such as rheumatoid arthritis, asthma, multiple sclerosis and psoriasis as well as a number of leukemias such as JML and CMML. GM-CSF, IL-3 and IL-5 signal through receptors containing α subunits specific to each cytokine and a common β subunit (βc). Cytokine stimulation leads to tyrosine phosphorylation of the βc and promotes specific responses such as proliferation, survival and activation of haemopoietic cells. Mouse knockout studies identified a key function of these cytokines in the activation of effector functions of myeloid cells, including production of reactive oxygen species (ROS) and phagocytosis. These earlier studies provide a link between cytokine signalling and inflammation, but the molecular mechanisms by which βc activation regulates effector cell functions, and the receptor motifs involved, are unknown. The aim of this thesis was to address two broad questions with regard to βc signalling: (1) Does βc regulate specific cellular responses by phosphotyrosine-independent mechanisms? (2) What are the molecular mechanisms by which βc initiates signalling to promote specific biological responses such as activation of effector cell functions? To address the first question, we have focussed on Serine 585, a potential 14-3-3 binding site which lies in the cytoplasmic potion of huβc. Out results show that the mutation huβc S585G disrupted the interaction of 14-3-3ζ with βc, whilst not affecting receptor tyrosine phosphorylation. Both mouse and human βc were shown to interact with 14-3-3 proteins, indicating that this interaction is conserved between these species. Significantly, a huβc S585G mutant was unable to promote haemopoietic cell survival in response to IL-3. These results identify a new mechanism by which cytokine receptors are able to couple to downstream signalling pathways that regulate cell survival. An approach was developed and optimised to analyse specific GM-CSF-mediated responses in monocytes/macrophages expressing wildtype or mutant huβc, (including huβc S585G that was defective in regulating survival). Bone marrow-derived muβc -/-;muβIL-3 -/- monocytes/macrophages were retrovirally transduced with constructs expressing wildtype or mutant huβc, along with huGMRα, then purified by FACS. Two assays were established to measure effector functions in the transduced monocyte/macrophages; (1) a flow cytometry assay for ROS production, and (2) an assay for phagocytosis. The capacity for GM-CSF to prime (i.e. enhance effector functions) ROS production and phagocytosis was investigated in huGMRα-transduced monocytes/macrophages. Our results have identified two key residues in the cytoplasmic domain of βc subunit: Tyrosine 577 (required for huβc interaction with the adaptor protein Shc) and serine 585 (required for 14-3-3 association), that are essential for the ability of GM-CSF to regulate key effector functions in monocytes/macrophages. These novel findings are significant in that they establish a molecular link between the GM-CSF/IL-3/IL-5 receptor and the regulation of both haemopoietic cell survival and inflammatory responses, and therefore have important implications in our understanding of inflammatory diseases such as rheumatoid arthritis and asthma. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1317007 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2008

<p>This study shows that herbs can be effectively screened for potiential bio-activity using in vitro methods. Further studies will be needed to better explore Artemisia afra&rsquo / s effect on immunoregulation, particularly long term effects of the herb on the immune system and its effect on other disease states.</p>

We are unceasingly exposed to potentially harmful microorganisms. The battle against threatening infectious agents includes activation of both the innate and of the adaptive immune systems. Illness responses are elicited and include inflammation, fever, decreased appetite, lethargy and increased sensitivity to painful stimuli in order to defeat invaders. While many of these signs of disease are controlled by the central nervous system, it has remained an enigma how signals from the peripheral immune system reach the brain through its blood-brain barrier, which precludes macromolecules, including cytokines, from diffusing into the brain parenchyma. Previous findings indicate the existence of a pathway across the blood-brain barrier, which includes binding of the cytokine interleukin-1 (IL-1) to its receptor in the brain vessels, thereby inducing the production of the prostaglandin E2 (PGE2) synthesizing enzymes cyclooxygenase-2 (Cox-2) and microsomal prostaglandin E synthase-1 (mPGES-1), which ultimately synthesize PGE2. PGE2 subsequently binds to any of the four prostaglandin E2 (EP) -receptors. Previous results from our laboratory have suggested that this pathway plays a critical role in the febrile response to infectious stimuli. The present thesis aims at further investigating the molecular events underlying immune-to-brain signalling, with special emphasis on fever, hypothalamic-pituitary-adrenal (HPA) -axis activation and anorexia and their connection to signalling molecules of the cytokine and prostaglandin families, respectively. In paper I, the molecular processes linking the proinflammatory cytokine interleukin-6 (IL-6) and PGE2 in the febrile response were investigated. Both IL-6 and PGE2 have been shown to be critical players in the febrile response, although the molecular connections are not known, i.e. if IL-6 exerts its effects up- or downstream of PGE2. Mice deficient in IL-6 were unable to respond to bacterial lipopolysaccharide (LPS) with a febrile response, but displayed similar induction of Cox-2 and mPGES-1, and similar concentrations of PGE2 in the cerebrospinal fluid as wild-type mice. Paradoxically, the IL-6 deficient mice responded with a dose-dependent elevation of body temperature in response to intracerebroventricularly injected PGE2. Furthermore, IL-6 per se was not pyrogenic when injected peripherally in mice, and did not cause increased levels of PGE2 in cerebrospinal fluid. IL-6 deficient mice were not refractory to the action of PGE2 because of excess production of some hypothermia-producing factor, since administration of a Cox-2 inhibitor in LPS-challenged IL-6 deficient mice did not unmask any hypothermic response, and neutralization of tumor necrosis factor α (TNFα), associated with hypothermia, did not produce fever in LPS-challenged IL-6 deficient mice. These data indicate that IL-6 rather than exerting its effects up- or down-stream of PGE2 affects some process in parallel to PGE2, perhaps by influencing the diffusion and binding of PGE2 onto its target neurons. In papers II and III, we injected the proinflammatory cytokine IL-1β in free-fed wild-type mice, in mice with a deletion of the gene encoding mPGES-1, or in mice deficient in the EP1, EP2 and EP3. Food intake was continuously measured during their active period, revealing that mPGES-1 deficient mice were almost completely resistant to anorexia induced by IL-1β. However, all of the investigated EP receptor deficient mice exhibited a normal profound anorexic response to IL-1β challenge, suggesting that the EP4 is the critical receptor that mediates IL-1β-induced anorexia. We also investigated the role of mPGES-1 in anorexia induced by lipopolysaccharide (LPS) in mPGES-1 deficient mice. The profound anorexic response after LPS-challenge was similar in mPGES-1 deficient and wild-type mice. To further investigate the anorectic behaviour after LPS injection, we pre-starved the animals for 22 hours before injecting them with LPS. In this paradigm, the anorexia was less profound in mPGES-1 knock-out mice. Our results suggest that while the inflammatory anorexia elicited by peripheral IL-1β seems largely to be dependent on mPGES-1-mediated PGE2 synthesis, similar to the febrile response, the LPS-induced anorexia is independent of this mechanism in free-fed mice but not in pre-starved animals. In papers IV and V, the role of prostanoids for the immune-induced HPA-axis response was investigated in mice after genetic deletion or pharmacological inhibition of prostanoid-synthesizing enzymes, including Cox-1, Cox-2, and mPGES-1. The immediate LPS-induced release of ACTH (adrenocorticotropic hormone and corticosteroids was critically dependent on Cox-1 derived prostanoids and occurred independently of Cox-2 and mPGES-1 derived PGE2. In contrast, the delayed HPA-axis response was critically dependent on immune-induced PGE2, synthesized by Cox-2 and mPGES-1, and occurred independently of Cox-1 derived enzymes. In addition, in the mPGES-1 deficient mice, the synthesis of CRH hnRNA and mRNA was decreased in the paraventricular nucleus of the hypothalamus after LPS-challenge, indicating that the delayed hormone secretion was mediated by PGE2-induced gene-transcription of CRH in the hypothalamus. The expression of the c-fos gene and Fos protein, an index of synaptic activation, was maintained in the paraventricular nucleus and its brainstem afferents both after unselective and Cox-2 selective inhibition as well as in Cox-1, Cox-2, and mPGES-1 knock-out mice. This suggests that the immune-induced neuronal activation of autonomic relay nuclei occurs independently of prostanoid synthesis and that it is insufficient for eliciting stress hormone release.

The leper is the ultimate symbol of the social outcast. Plagued by connotations of not just contagion but of sinfulness and moral depravity, lepers have long been stigmatized and excluded from society. The Hebrew Bible declared them to be unclean, and their influence was believed to be wholly corrupting, as if their physical deformities were an external sign of their defiled souls. In the Middle Ages, those diagnosed with leprosy were made to undergo a particularly severe ritual that closely resembled the office of the dead, making them effectively dead to the world. They were then isolated from the healthy population in leprosariums, and their movements and behaviors were strictly controlled. However, their exclusion can be seen as serving a larger purpose than just the protection of normal society from infection in that it can be used by those in power as a mechanism of social control. The imputation of danger to undesirable persons of a given community ensures that they will be duly feared and ostracized. It is within this context that Italo Calvino and Umberto Eco make use of the idea of the leper as a social outlier in their novels, Il visconte dimezzato and Il nome della rosa, as a way to critique certain processes of exclusion, namely the construction and stigmatization of a social “other” as a means of maintaining social order. This report draws on the historical and literary treatments of the leper to discuss the ways in which Calvino and Eco successfully employ the image of the leper to represent the machinery of exclusion and to shed light on the continued marginalization of outcast groups down to the present day. / text

No description available.

Darbo tikslas – nustatyti kompiuterizuoto inhibicinio kontrolės testo (IKT), IL-6, amoniako bei įprastinių kraujo rodiklių vertę diagnozuojant kognityvinius sutrikimus sergantiems lėtinėmis kepenų ligomis. Darbo uždaviniai: nustatyti kognityvinių sutrikimų dažnį, galimus rizikos veiksnius, palyginti IKT ir kraujo testų rezultatus lėtinio hepatito ir kepenų cirozės grupėse; nustatyti IKT bei IL-6, įprastinių kraujo testų vertę minimaliai hepatinei encefalopatijai (MHE). Iki šiol netirta ar pacientai, sergantys lėtiniu hepatitu ir kognityviniais sutrikimais, neturi analogiškų IKT rodiklių pakitimų, IL-6 koncentracijos padidėjimo kaip sergantieji kepenų ciroze ir MHE. Netirta kokie kraujo ar IKT rodikliai kognityvinius sutrikimus prognozuoja geriausia. Į tyrimą įtraukti 62 sergantieji kepenų ciroze be hepatinės encefalopatijos, 73 lėtiniu hepatitu bei 53 sveiki asmenys. Tą pačią dieną buvo atliekami kraujo tyrimai, psichometriniai testai ir IKT. Lėtinio hepatito grupėje kognityviniai sutrikimai nustatyti 54,8 %, о kepenų cirozės grupėje MHE ¬ 71,0 % tiriamųjų asmenų. Kognityvinius sutrikimus predisponuoja trumpesnė mokymosi trukmė, fibrozės laipsnis, dvigubas etiologinis veiksnys, amžius ir lytis įtakos neturi. Lėtinio hepatito grupėje kognityviniai sutrikimai koreliuoja su IKT rodikliais ir kepenų fermentų koncentracijos padidėjimu, o kepenų cirozių grupėje su IKT rodikliais ir IL-6 koncentracija kraujyje. Išvados: Kognityvinius sutrikimus sergant lėtiniu hepatitu ar... [toliau žr. visą tekstą] / The aim of the study was to ascertain a value of computerized inhibitory control test (ICT), routine blood tests, peripheral blood ammonia and IL-6 concentration for diagnosis of cognitive disorders in patients with chronic liver diseases. Tasks: to assess a frequency of cognitive impairments and associated risk factors and to compare ICT and blood tests results in chronic hepatitis and cirrhotic patients; to ascertain ICT, IL-6 and routine blood tests values for diagnosis of minimal hepatic encephalopathy (MHE). Until now there were no studies performed whether chronic hepatitis patients with cognitive disorders have analogous ICT, IL-6 and other tests abnormalities as cirrhotic patients with MHE. It has not been studied which ICT and other tests results predict best the cognitive disorders in such patients. 62 cirrhotic patients without overt hepatic encephalopathy, 73 chronic hepatitis and 53 healthy individuals were enrolled. On the same day blood tests, psychometric and ICT tests were performed by every participant. Cognitive disorders were detected in 54,8% of chronic hepatitis patients. In cirrhotic patients MHE was found in 71,0%. Cognitive disorders predispose shorter study time, the fibrosis score, double etiologic factor, while age and gender has no influence. In chronic hepatitis patients the cognitive impairments correlate with ICT and elevated liver enzymes. In cirrhotic patients cognitive disorders correlate with ICT and IL-6 concentration. Conclusion: the... [to full text]

The aim of the study was to ascertain a value of computerized inhibitory control test (ICT), routine blood tests, peripheral blood ammonia and IL-6 concentration for diagnosis of cognitive disorders in patients with chronic liver diseases. Tasks: to assess a frequency of cognitive impairments and associated risk factors and to compare ICT and blood tests results in chronic hepatitis and cirrhotic patients; to ascertain ICT, IL-6 and routine blood tests values for diagnosis of minimal hepatic encephalopathy (MHE). Until now there were no studies performed whether chronic hepatitis patients with cognitive disorders have analogous ICT, IL-6 and other tests abnormalities as cirrhotic patients with MHE. It has not been studied which ICT and other tests results predict best the cognitive disorders in such patients. 62 cirrhotic patients without overt hepatic encephalopathy, 73 chronic hepatitis and 53 healthy individuals were enrolled. On the same day blood tests, psychometric and ICT tests were performed by every participant. Cognitive disorders were detected in 54,8% of chronic hepatitis patients. In cirrhotic patients MHE was found in 71,0%. Cognitive disorders predispose shorter study time, the fibrosis score, double etiologic factor, while age and gender has no influence. In chronic hepatitis patients the cognitive impairments correlate with ICT and elevated liver enzymes. In cirrhotic patients cognitive disorders correlate with ICT and IL-6 concentration. Conclusion: the... [to full text] / Darbo tikslas – nustatyti kompiuterizuoto inhibicinio kontrolės testo (IKT), IL-6, amoniako bei įprastinių kraujo rodiklių vertę diagnozuojant kognityvinius sutrikimus sergantiems lėtinėmis kepenų ligomis. Darbo uždaviniai: nustatyti kognityvinių sutrikimų dažnį, galimus rizikos veiksnius, palyginti IKT ir kraujo testų rezultatus lėtinio hepatito ir kepenų cirozės grupėse; nustatyti IKT bei IL-6, įprastinių kraujo testų vertę minimaliai hepatinei encefalopatijai (MHE). Iki šiol netirta ar pacientai, sergantys lėtiniu hepatitu ir kognityviniais sutrikimais, neturi analogiškų IKT rodiklių pakitimų, IL-6 koncentracijos padidėjimo kaip sergantieji kepenų ciroze ir MHE. Netirta kokie kraujo ar IKT rodikliai kognityvinius sutrikimus prognozuoja geriausia. Į tyrimą įtraukti 62 sergantieji kepenų ciroze be hepatinės encefalopatijos, 73 lėtiniu hepatitu bei 53 sveiki asmenys. Tą pačią dieną buvo atliekami kraujo tyrimai, psichometriniai testai ir IKT. Lėtinio hepatito grupėje kognityviniai sutrikimai nustatyti 54,8 %, о kepenų cirozės grupėje MHE ¬ 71,0 % tiriamųjų asmenų. Kognityvinius sutrikimus predisponuoja trumpesnė mokymosi trukmė, fibrozės laipsnis, dvigubas etiologinis veiksnys, amžius ir lytis įtakos neturi. Lėtinio hepatito grupėje kognityviniai sutrikimai koreliuoja su IKT rodikliais ir kepenų fermentų koncentracijos padidėjimu, o kepenų cirozių grupėje su IKT rodikliais ir IL-6 koncentracija kraujyje. Išvados: Kognityvinius sutrikimus sergant lėtiniu hepatitu ar... [toliau žr. visą tekstą]

<p>This study shows that herbs can be effectively screened for potiential bio-activity using in vitro methods. Further studies will be needed to better explore Artemisia afra&rsquo / s effect on immunoregulation, particularly long term effects of the herb on the immune system and its effect on other disease states.</p>