Diss. (sammanfattning) Linköping : Univ., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 7 uppsatser.

Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Vita. Bibliography: 155-170.

Abstract Respiratory syncytial virus (RSV) infection may be associated with the development of asthma and atopy. The aim of the present study was to investigate this association and the related immunological mechanisms. Seventy-six children admitted to Oulu University Hospital in 1991–1994 for an RSV infection at an age of less than 12 months and healthy controls were called for a visit at the age of 6–10 years. Twenty subjects (26%) had asthma compared with 12 controls (16%) (difference 11%, 95% confidence interval (CI) –3% to 24%). Asthma had been diagnosed significantly earlier in the subjects. Eight per cent of the subjects had at least one positive skin prick test as compared with 43% of the controls (difference –35%, 95% CI –50% to –19%). Serum concentrations of interferon-γ and soluble intercellular adhesion molecule -1 were significantly higher among the subjects than among the controls and among the subjects with asthma or current wheezing than among the corresponding controls. All children born in Finland in 1986–1995 were arranged in birth cohorts by month and year of birth and grouped by exposure to an RSV epidemic at age 0–6 months, resulting in 97 exposed and 23 unexposed cohorts. The proportions of children taking asthma medication or receiving special reimbursement for asthma medication in 1995–2002 were similar in the unexposed and exposed cohorts. Altogether 47 children born between August and November 2001 with a cord blood sample taken were admitted to hospital (n = 26) or seen in an outpatient department (n = 21) for RSV infection before the age of six months. Twenty-eight children had some other respiratory viral infection and 84 children formed a group of healthy controls. High scores on a factor combining the cord blood interleukin-6 and interleukin-8 responses (as derived by factor analysis) were shown in logistic regression analysis to predict hospitalization for RSV infection by comparison with the healthy controls (odds ratio 2.29, 95% CI 1.21 to 4.33). We suggest that RSV does not induce asthma but inborn features of immunity affect the severity of RSV infection and the postinfectious development of asthma.

Dissertation (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2008. / Vita. Bibliography: p. 174-213.

<p>UVOD: Gojaznost je hronično, multifaktorijalno i kompleksno oboljenje povezano sa povećanim rizikom od aterosklerotskih kardiovaskularnih bolesti (KVB). Disfunkcija vaskularnog endotela predstavlja rani događaj u patofiziolo&scaron;kom kontinuumu aterosklerotskog procesa, a produženo izlaganje vaskularnog endotela faktorima rizika za aterosklerozu udruženim sa gojaznosti (insulinska rezistencija, dislipidemija, proinflamatorno/protrombozno stanje), može doprineti procesima aktivacije/disfunkcije endotela i progresiji ateroskleroze u supkliničku, odnosno kliničku formu bolesti. CILJ: Uporediti koncentracije solubilne forme adhezionih molekula &ndash; intracelularnog adhezivnog molekula &ndash;1 (sICAM&ndash;1) i E selektina (sE&ndash;selektin), između ispitanika sa hiperalimentacionim tipom gojaznosti i normalno uhranjenih zdravih ispitanika, kao i utvrditi eventualno postojanje razlika u koncentraciji sICAM&ndash;1 i sE&ndash;selektina između ispitanika kod kojih je merenjem debljine kompleksa intima medija karotidne arterije (IMK) uočen supklinički stadijum ateroskleroze i ispitanika koji imaju normalnu debljinu IMK. Ispitati povezanost parametara telesne kompozicije (ukupne masne mase tela i masne mase abdominalnih depoa), cirkuli&scaron;ućih koncentracija biomarkera disfunkcije vaskularnog endotela (sICAM&ndash;1 i sE&ndash;selektina) i IMK kod ispitanika sa hiperalimentacionim tipom gojaznosti. MATERIJAL I METODE: U istraživanje je uključeno 60 ispitanika sa hiperalimentacionim tipom gojaznosti bez pridruženih komorbiditeta i 30 zdravih normalno uhranjenih učesnika usklađenih sa ispitanicima po godinama života i polu koji su činili kontrolnu grupu. Svim ispitanicima su urađena antropometrijska merenja, analiza komponenata telesne kompozicije (bioelektrična impedansna analiza, Tanita Body Composition Analyzer BC &ndash; 418 MA III), laboratorijska analiza uzoraka krvi na automatizovanim analizatorskim sistemima sa određivanjem parametara metabolizma glukoze (bazalno i 2 h u toku oralnog glukoza tolerans testa), lipida i lipoproteina, inflamacije i homocisteina. Određivanje serumske koncentracije sICAM&ndash;1 i sE&ndash;selektina je vr&scaron;eno ELISA tehnikom (R&amp;D Systems, Inc. Minneapolis, USA). Vrednosti IMK&ndash;a su određivane pomoću karotidnog dupleks ultrazvuka (Aloka SSD&ndash;650 US system, Tokyo), a na osnovu izmerenih (IMK) i normalno očekivanih vrednosti IMK za svakog ispitanika je izračunavan IMK Z&ndash;skor. Supklinički stadijum ateroskleroze je definisan kao vrednost IMK Z&ndash;skora veća od 1 (&scaron;to odgovara vrednosti IMK većoj od 95 percentila normalno očekivane vrednosti u odnosu na pol i godine života ispitanika). REZULTATI: Ispitanici sa hiperalimentacionim tipom gojaznosti su imali statistički značajno vi&scaron;e vrednosti medijane serumske koncentracije sE&ndash;selektina u poređenju sa medijanom serumske koncetracije sE&ndash;selektina učesnika u kontrolnoj grupi (36,2 (33,21&ndash;43.7) vs. 25,14 (23,1&ndash;29,48) ng/mL, P=0,00). Gojazni ispitanici III stepena gojaznosti su imali statistički značajno vi&scaron;u medijanu serumske koncenracije sE&ndash;selektina u odnosu na medijanu sE&ndash;selektina u ispitanika I stepena gojaznosti (41,5 (36,58&ndash;49,48) vs. 34,34 (22,49&ndash;36,62) ng/mL, P=0,00), odnosno medijanu sE&ndash;selektina u ispitanika II stepena gojaznosti (41,5 (36,58&ndash;49,48) vs. 32,1 (26,1&ndash;43,64) ng/mL, P=0,00). Nije uočena statistički značajna razlika u medijani serumske koncentracije sE&ndash;selektina između ispitanika I i II stepena gojaznosti (34,34 (22,49&ndash;36,62) vs. 32,1 (26,1&ndash;43,64) ng/mL, P=0,12). Gojazni ispitanici su imali statistički značajno vi&scaron;e vrednosti medijane serumske koncentracije sICAM&ndash;1 u poređenju sa medijanom serumske koncetracije sICAM&ndash;1 učesnika u kontrolnoj grupi (266,8 (245,8&ndash;326,73) vs.183,32 (167,9&ndash;208,57), P=0,00). U ispitivanoj grupi gojaznih uočena je statistički značajna razlika u medijani koncentracije sICAM&ndash;1 između ispitanika u I, II i III stepena gojaznosti (200,6 (190,26 - 264,4) vs. 278,5 (219,54 - 343,24) vs. 329,6 (259,2 - 350,34) ng/mL, P=0,00). Učestalost IMK Z&ndash;skor &gt; 1 je bila statistički značajno eća u gojaznih ispitanika u odnosu na kontrolnu grupu (36/60 vs. 7/30, P=0,00). Ispitanici sa IMK Z&ndash;skor &gt; 1 su imali statistički značajno vi&scaron;u medijanu koncentracije sICAM&ndash;1 u odnosu na ispitanike kod kojih je IMK Z&ndash;skor &le; 1 (295,4 (238,46&ndash;340,38) vs. 244,2 (227,35&ndash;260,38), P=0.00). Regresionom analizom (R2=0,71, korigovani R2=0,59) je utvrđeno da su parametri hsCRP (&beta;=0,45, P=0,00), HOMA&ndash;IR (&beta;=0,44, P=0,035) i ISI (&beta;=&ndash;0,36, P=0,028) nezavisno i statistički značajno povezani sa serumskom koncentracijom sE&ndash;selektina. Regresionom analizom (R2=0,65, korigovani R2=0,56) je utvrđeno da parametri ITM (&beta;=0,55, P=0,00), trigliceridi (&beta;=0,30, P=0,00), HDL holesterol (&beta;=&ndash;0,31, P=0,00), odnos TG/HDL&ndash;holesterol (&beta;=0,33, P=0,01), hsCRP (&beta;=0,31, P=0,00) i fibrinogen (&beta;=0,34, P=0,00) su nezavisno i statistički značajno povezani sa serumskom koncentracijom sICAM&ndash;1. U faktorskoj analizi je izdvojeno pet faktora &ldquo;gojaznost&rdquo;, &ldquo;insulinska rezistencija&rdquo;, &ldquo;aterogeni faktor&rdquo;, &ldquo;endotelna disfunkcija i vaskularna inflamacija&rdquo; i &ldquo;metabolički faktor&rdquo; koji obja&scaron;njavaju 69.72% ukupne varijanse ispitivanog uzorka. U multivarijabilnom modelu sa svim faktorima zajedno kojim je obja&scaron;njeno ukupno 75% varijanse, jedino je faktor gojaznost imao statički značajan i nezavistan uticaj na vrednost IMK Z&ndash;skor &gt; 1 (OR=2,74 (CI 1,18&ndash;6,33), P=0,019). U faktoru gojaznost su se izdvojili parametri: FAT trunk (%), FAT (%), OS (cm), ITM (kg/m2), LDL &ndash; holesterol (mmol/L), SP (mmHg), HOMA1&ndash;%B, fibrinogen (g/L), ApoB/apoA-I i hsCRP (mg/L). Univarijantom logističkom regresijom je uočeno da porast u koncentraciji LDL&ndash;H (OR=5,33 (CI 1,9&ndash;14,2), P=0,02) i koncentraciji hsCRP&ndash;a (OR=2,53 (CI 1,3&ndash;3,98),P=0,017) povećava rizik za postojanje vrednosti IMK Z&ndash;skor &gt; 1. ZAKLJUČAK: Cirkuli&scaron;uće serumske koncentracije biomarkera disfunkcije vaskularnog endotela, sE&ndash;selektina i sICAM&ndash;1, su značajno vi&scaron;e kod ispitanika sa hiperalimentacionim tipom gojaznosti u odnosu na njihove koncentracije u normalno uhranjenih ispitanika. U gojaznih ispitanika, koncentracija sE&ndash;selektina je povezana sa vrednostima indeksa insulinske rezistencije i biomarkera inflamacije, dok je koncentracija sICAM&ndash;1 značajno povezana sa udelom masne mase u ukupnoj telesnoj masi, vrednostima biomarkera inflamacije i proaterogenih lipidskih parametara. Ispitanici kod kojih postoji uvećanje abdominalnih masnih depoa i ukupnog udela masnog tkiva u telesnoj masi, vrednosti SKP, koncentracije LDL &ndash; holesterola, vrednosti lipoproteinskog indeksa ApoAI/apoB, bazalne insulinemije i biomarkera inflamacije, imaju trostruko povećan rizik od supkliničkog stadijuma ateroskleroze. U gojaznih osoba prilikom procene rizika od aterosklerotskih KVB, potrebno je utvrditi fenotipske osobine vaskularnog endotela i eventualno postojanje supkliničkog stadijuma ateroskleroze, da bi se definisale adekvatne preventivne mere i sagledale potencijalne terapijske mogućnosti.</p> / <p>INTRODUCTION: Obesity is a chronic, multifactorial and complex disease associated with an increased risk of atherosclerotic cardiovascular diseases (CVD). Vascular endothelial dysfunction is an early event in the pathophysiological continuum of atherosclerotic process. The prolonged exposure of vascular endothelium to classical and obesity associated risk factors (insulin resistance, dyslipidemia, proinflammatory state) could further promote deterioration of endothelial function and progression of atherosclerosis to subclinical or clinical form of disease. OBJECTIVE: The aim of the study was to compare the concentration of soluble forms of adhesion molecules, intracellular adhesion molecule-1 (sICAM-1) and E-selectin (sE-selectin), between obese subjects and normal weight healthy subjects, as well as to determine the possible existence of differences in concentration of sICAM-1 and sE-selectin among subjects with subclinical stage of atherosclerosis (assessed by measuring the thickness of the intima media complex of the carotid artery (IMT)), and subjects who have a normal value of IMT. Also, the aim was to determine the association between the parameters of body composition (total body fat mass and fat mass intra-abdominal depots), circulating concentrations of sICAM-1 and sE-selectin, and value of IMT in obese subjects. MATERIALS AND METHODS: The study included 60 obese nondiabetic subjects, without preexisting CVD and other associated comorbidity, and 30 healthy normal weight age and sex matched participants. All subjects underwent anthropometric measurements, analysis of the components of body composition (bioelectrical impedance analysis, Tanita Body Composition Analyzer BC - 418 MA III), laboratory analysis of blood samples (automated analyzer systems) with determining the parameters of glucose metabolism (basal and 2 h during the oral glucose tolerance test), lipids and lipoproteins, inflammation and homocysteine. Serum concentrations of sICAM-1 and sE-selectin were determined by ELISA (R &amp; D Systems, Inc., Minneapolis, USA). The values of IMK were determined by carotid duplex ultrasound (Aloka &ndash; ProSound ALPHA 10). IMK Z-score was calculated using the measured and the normal expected values of IMT for each patient. Subclinical stage of atherosclerosis was defined as the value of IMT Z-score greater than 1 (corresponding to the 95th sex-age-specific percentile of IMT measurements). RESULTS: Obese subjects had significantly higher median sE-selectin serum concentrations compared to median serum concentrations of sE-selectin in the normal weight subjects (36.2 (33.21-43.7) vs 25.14 (23.1-29.48) ng/mL, P=0.00). Morbid obesity subjects had significantly higher sE-selectin median serum concentration compared to the median sE-selectin concentration in moderate obese subjects (41.5 (36.58-49.48) vs 34.34 (22.49-36.62) ng/mL, P=0.00), and compared to the median sE-selectin concentration in severely obese subjects (41.5 (36.58-49.48) vs. 32.1 (26.1-4364) ng / mL, P=0.00). Obese subjects had significantly higher median sICAM-1 serum concentration compared to median sICAM-1 serum concentration in the control group (266.8 (245.8-326.73) vs. 183.32 (167.9-208.57), P=0.00). In the obese group, we observed a statistically significant difference in median sICAM-1 serum concentrations between moderate, severely and morbid obese subjects (200.6 (190.26-264.4) vs. 278.5 (219.54-343.24) vs. 329.6 (259.2-350.34) ng/mL, P=0.00). The frequency of IMT Z-score&gt; 1 was significantly higher in the obese group compared to control group (36/60 vs. 7/30, P=0.00). Subjects with IMT Z-score&gt; 1 had significantly higher median concentrations of sICAM-1 compared to those in which the IMK Z-score &le; 1 (295.4 (238.46-340.38) vs. 244.2 ( 227.35-260.38), P=0.00). In regression analysis (R2=0.71, adjusted R2=0.59), hsCRP (&beta;=0.45, P=0.00), HOMA-IR (&beta;=0.44, P=0.035) and ISI (&beta;=-0.36, P=0.028) were independently and significantly associated with serum sE-selectin concentration. In regression analysis (R2=0.65, adjusted R2=0.56), BMI (&beta;=0.55, P=0.00), triglycerides (&beta;=0.30, P=0.00), HDL cholesterol (&beta;=-0.31, P=0.00), the ratio of TG/HDL-cholesterol ratio (&beta;=0.33, P=0.01), hsCRP (&beta;=0.31, P=0.00 ) and fibrinogen (&beta;=0.34, P=0.00) were independently and significantly associated with serum sICAM-1 concentration. In the Factor analysis, five factors &quot;obesity&quot;, &quot;insulin resistance&quot;, &quot;atherogenic factor,&quot; &quot;endothelial dysfunction and vascular inflammation&quot; and &quot;metabolic factor&quot; explained 69.72% of the total variance of the test sample. In a multivariate model with all the factors together (75% of the total variance), &quot;obesity&quot; factor was significantly and independently associated with IMT Z-score&gt; 1 (OR=2.74 (CI 1.18-6.33), P=0.019). The &quot;obesity&quot; factor consisted of parameters: trunk fat (%), fat (%), waist (cm), BMI (kg/m2), LDL &ndash; cholesterol (mmol/L), systolic blood presure (mmHg), HOMA1-% B, fibrinogen (g/L), Apo B/apoA-I and hsCRP (mg/L). Logistic regression analysis showed that independent predictors of IMT Z-score&gt; 1 were LDL-cholesterol (OR=5.33(CI 1.9-14.2), P=0.02) and hsCRP (OR=2.53 (CI 1.3-3.98), P=0.017). CONCLUSION: Circulating serum concentrations of endothelial dysfunction biomarkers, sE-selectin and sICAM-1, were significantly higher in obese subjects compared to concentration in the normal weight subjects. In obese subjects, the concentration of sE-selectin was associated with insulin resistance and biomarkers of inflammation, whereas sICAM-1 concentration was associated with fat mass, inflammation biomarkers and the proatherogenic lipid parametars. In individuals with increased abdominal fat depots and total proportion of fat mass in the body weight, values of SBP, LDL-C, ApoB/apoA-I, basal insulin levels and biomarkers of inflammation, there is threefold increased risk of subclinical stages of atherosclerosis. In order to define an adequate preventive measures and possible therapeutic options for atherosclerotic CVD in obese subjects, it is necessary to assess the phenotypic characteristics of vascular endothelium and possible presence of subclinical stage of atherosclerosis.</p>

Yes / Alterations of Endothelial cells (ECs) play a critical role in different pathogenesis of many serious human diseases, and dysfunction of the vascular endothelium is an indicator for human disorders. Endothelial dysfunction is considered to be an early indicator for atherosclerosis, which is characterised by overexpression of adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Hydrogen peroxide (H2O2) released via neutrophils is an important mediator of endothelial cell function. Ambient production of superoxide anion (O2−) and subsequently H2O2 at low levels is critical for regulating endothelial cell functions and proliferation. In this study, we investigated the effects of H2O2 on the expression of adhesion molecules VCAM-1 and ICAM-1 in cultured human umbilical vein endothelial cells (HUVECs). Intracellular superoxide anion production was detected by using p-Nitro Blue Tetrazolium (NBT) assay. Our results showed that administration of 100μM of H2O2 on HUVECs for 2, 6, 12 and 24 h induced a time-dependent increase in ICAM-1 and VCAM-1 mRNA and protein expression levels with a significant increase observed from 6 h. HUVECs exposed to H2O2 exhibit increased O2−, suggesting that H2O2 induced oxidative stress may be a reasonable for atherosclerosis. This increase can be reduced by the flavonoid, N-acetyl cysteine (NAC). The modulation of endothelial cell function through this mechanism may underlie the contribution of H2O2 to the development of vascular disease.

Les phospholipases A2 sécrétées (sPLA2) font partie d’une grande famille d’enzymes impliquées dans la synthèse d’écosanoïdes, de chimiokines et dans l’expression de molécules d’adhérence. Ce groupe comprend dix isoformes différentes (sPLA2-IB, -IIA, -IIC, -IID, -IIE, -IIF, -III, -V, -X et XII) dont la majorité sont surexprimées en présence de molécules pro-inflammatoires telles que l’interleukine-1β (IL-1 β) et le lipopolysaccharide bactérien (LPS). La sPLA2-IIA fut longtemps considérée comme la principale sPLA2 associée à l’inflammation. Toutefois, un nombre grandissant d’études suggère l’implication d’autres isoformes dans la réponse inflammatoire. Étant donné la similarité structurelle des différentes isoformes de sPLA2, la majorité des inhibiteurs présentement disponibles sont non spécifiques et bloquent simultanément plus d’une sPLA2. De ce fait, encore peu de choses sont connues quant au rôle précis de chacune des sPLA2 dans la réponse inflammatoire. Ayant accès à des souris génétiquement modifiées n’exprimant pas la sPLA2-V (sPLA2-V-/-), nous avons donc investigué le rôle spécifique de la sPLA2-V dans le recrutement leucocytaire induit par le LPS, ainsi que sa capacité à moduler l’expression de certaines molécules d’adhérence. Pour ce faire, nous avons utilisé le modèle inflammatoire de la poche d’air sous-cutanée. L’administration de LPS dans la poche d’air de souris contrôles (WT) entraîne un recrutement leucocytaire important. Cet appel de cellules inflammatoires est cependant significativement diminué chez les souris sPLA2-V-/-. De plus, l’expression des molécules d’adhérence VCAM-1 et ICAM-1 est également diminuée chez les souris sPLA2-V-/- comparativement aux souris WT. Nos résultats démontrent donc le rôle important de la sPLA2-V dans le recrutement leucocytaire et l’expression de molécules d’adhérence induits par le LPS, confirmant ainsi l’implication de cette enzyme dans le processus inflammatoire. / Secretory phospholipases A2 (sPLA2s) are well known for their contribution in the biosynthesis of inflammatory eicosanoids. These enzymes also participate in the inflammatory process by regulating chemokine production and protein expression of adhesion molecules. The majority of sPLA2 isoforms are up-regulated by proinflammatory stimuli such as bacterial lipopolysaccharide (LPS), which predominantly increases the expression of group V sPLA2 (sPLA2-V). Furthermore, it has recently been shown that sPLA2-V is a critical messenger in the regulation of cell migration during allergic airway responsiveness. Herein, we investigated the effect of sPLA2-V on LPS-mediated leukocyte recruitment and its capacity to modulate adhesion molecule expression. We conducted our study in the murine air pouch model, using sPLA2-V null mice (sPLA2-V-/-) and control wild-type (WT) littermates. We observed that LPS (1 μg/mL)-mediated leukocyte migration in sPLA2-V-/- was attenuated by 52 and 86% after 6 and 12 hours of treatment, respectively, as compared to WT mice. In WT mice, treatment with the cell-permeable sPLA2 inhibitor (12-epi-scalaradial; SLD) reduced LPS-mediated leukocyte recruitment by 67%, but had no additional inhibitory effect in sPLA2-V-/- mice. Protein analyses from the air pouch skin were carried out upon LPS-challenge, and the expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 were both significantly reduced in sPLA2-V-/- mice as compared to control WT mice. Together, our data demonstrate the role of sPLA2-V in LPS-induced ICAM-1 and VCAM-1 protein overexpression and leukocyte recruitment, supporting the contribution of sPLA2-V in the development of inflammatory innate immune responses.

Les phospholipases A2 sécrétées (sPLA2) font partie d’une grande famille d’enzymes impliquées dans la synthèse d’écosanoïdes, de chimiokines et dans l’expression de molécules d’adhérence. Ce groupe comprend dix isoformes différentes (sPLA2-IB, -IIA, -IIC, -IID, -IIE, -IIF, -III, -V, -X et XII) dont la majorité sont surexprimées en présence de molécules pro-inflammatoires telles que l’interleukine-1β (IL-1 β) et le lipopolysaccharide bactérien (LPS). La sPLA2-IIA fut longtemps considérée comme la principale sPLA2 associée à l’inflammation. Toutefois, un nombre grandissant d’études suggère l’implication d’autres isoformes dans la réponse inflammatoire. Étant donné la similarité structurelle des différentes isoformes de sPLA2, la majorité des inhibiteurs présentement disponibles sont non spécifiques et bloquent simultanément plus d’une sPLA2. De ce fait, encore peu de choses sont connues quant au rôle précis de chacune des sPLA2 dans la réponse inflammatoire. Ayant accès à des souris génétiquement modifiées n’exprimant pas la sPLA2-V (sPLA2-V-/-), nous avons donc investigué le rôle spécifique de la sPLA2-V dans le recrutement leucocytaire induit par le LPS, ainsi que sa capacité à moduler l’expression de certaines molécules d’adhérence. Pour ce faire, nous avons utilisé le modèle inflammatoire de la poche d’air sous-cutanée. L’administration de LPS dans la poche d’air de souris contrôles (WT) entraîne un recrutement leucocytaire important. Cet appel de cellules inflammatoires est cependant significativement diminué chez les souris sPLA2-V-/-. De plus, l’expression des molécules d’adhérence VCAM-1 et ICAM-1 est également diminuée chez les souris sPLA2-V-/- comparativement aux souris WT. Nos résultats démontrent donc le rôle important de la sPLA2-V dans le recrutement leucocytaire et l’expression de molécules d’adhérence induits par le LPS, confirmant ainsi l’implication de cette enzyme dans le processus inflammatoire. / Secretory phospholipases A2 (sPLA2s) are well known for their contribution in the biosynthesis of inflammatory eicosanoids. These enzymes also participate in the inflammatory process by regulating chemokine production and protein expression of adhesion molecules. The majority of sPLA2 isoforms are up-regulated by proinflammatory stimuli such as bacterial lipopolysaccharide (LPS), which predominantly increases the expression of group V sPLA2 (sPLA2-V). Furthermore, it has recently been shown that sPLA2-V is a critical messenger in the regulation of cell migration during allergic airway responsiveness. Herein, we investigated the effect of sPLA2-V on LPS-mediated leukocyte recruitment and its capacity to modulate adhesion molecule expression. We conducted our study in the murine air pouch model, using sPLA2-V null mice (sPLA2-V-/-) and control wild-type (WT) littermates. We observed that LPS (1 μg/mL)-mediated leukocyte migration in sPLA2-V-/- was attenuated by 52 and 86% after 6 and 12 hours of treatment, respectively, as compared to WT mice. In WT mice, treatment with the cell-permeable sPLA2 inhibitor (12-epi-scalaradial; SLD) reduced LPS-mediated leukocyte recruitment by 67%, but had no additional inhibitory effect in sPLA2-V-/- mice. Protein analyses from the air pouch skin were carried out upon LPS-challenge, and the expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 were both significantly reduced in sPLA2-V-/- mice as compared to control WT mice. Together, our data demonstrate the role of sPLA2-V in LPS-induced ICAM-1 and VCAM-1 protein overexpression and leukocyte recruitment, supporting the contribution of sPLA2-V in the development of inflammatory innate immune responses.

Porcine circovirus type 2 (PCV2) is the causative agent of porcine circovirus-associated disease (PCVAD). Porcine reproductive and respiratory syndrome (PRRS) is caused by PRRS virus (PRRSV). Both PCV2 and PRRSV have caused devastating diseases in the swine industry worldwide, resulting in immense economic losses. One of the most common co-infections in the swine industry is PCV2 and PRRSV. The aim of this dissertation research is to explore different experimental approaches to develop novel vaccines against the two major pathogens affecting swine production and study the basic mechanisms that may be involved in viral pathogenesis. Two types of porcine circovirus (PCV), PCV1 and PCV2, have been identified thus far. PCV1, first identified as a contaminant of the PK-15 cell line, is non-pathogenic and has a low prevalence in swine herds. PCV2 is highly prevalent in most swine-producing countries and is associated with clinical PCVAD. The non-pathogenic PCV1 shares similar genomic organization with PCV2. Previously, it has been demonstrated that a genetically modified infectious chimeric PCV1-2a virus can tolerate up to a 27 aa insertion in the C-terminus of the ORF2 without affecting infectivity and produce a dual immune response against PCV2cap and the inserted epitope tag. Therefore, we evaluated the use of the non-pathogenic PCV1 wild-type (wt) virus and chimeric PCV1-2a vaccine virus (vs) to express four known B-cell epitopes of PRRSV. Peptide epitopes of PRRSV-VR2385, including GP2II (aa 40–51, ASPSHVGWWSFA), GP3I (aa 61–72, QAAAEAYEPGRS), GP5I (aa 35–46, SSSNLQLIYNLT), and GP5IV (aa 187–200, TPVTRVSAEQWGRP) were inserted in frame into the C-terminus of the ORF2 of PCV1wt as well as the PCV1-2avs. Four PCV1-PRRSVEPI chimeric viruses and four PCV1-2a-PRRSVEPI chimeric viruses were successfully rescued and shown to be infectious in vitro and co-expressed PCV1cap or PCV2cap with each specific PRRSV epitope. Two independent animal studies were conducted to evaluate whether the non-pathogenic PCV1 can serve as a vaccine delivery vector and whether the PCV1-2a vaccine virus can be used to develop a bivalent vaccine against both PCV2 and PRRSV. We demonstrated that three PCV1-PRRSVEPI chimeric viruses and two PCV1-2a-PRRSVEPI chimeric viruses were infectious in pigs. Importantly, we demonstrated that the PCV1-PRRSVEPI and PCV1-2a-PRRSVEPI chimeric viruses not only induced specific PCV1 or PCV2 IgG antibody but also specific anti-PRRSV epitope antibody responses as well. Regardless of the PCV backbone used, we showed that the PCV-PRRSV chimeric viruses elicited neutralizing antibodies against PRRSV-VR2385. These results provided a proof of concept for the potential use of the non-pathogenic PCV1 as a vaccine delivery system for PRRSV or other swine pathogens and the use of PCV1-2a vaccine virus to generate a bivalent vaccine against both PCV2 and PRRSV. PRRSV causes a persistent infection and immunosuppression. Immunomodulation of the host immune system is caused by modulation of numerous interleukins, such as type I interferons, tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), and interleukin-12 (IL-12) in infected pigs. Antigen-presenting cells (APCs) are the first line of defense, and their infection plays an important role in innate-mediated immune regulation during early immune responses. Among the APCs, pulmonary alveolar macrophages (PAMs), pulmonary interstitial macrophages (PIMs), and dendritic cells (DCs) are the main targets for PRRSV replication. The role of PRRSV-DCs interaction is not fully understood, and current research focuses on the production and regulation of interferons through DC-SIGN receptors. In this study, we evaluated the immunomodulation of MoDCs by PRRSV through interactions with the pDC-SIGN receptor, by blocking pDC-SIGN with recombinant hICAM-3-Fc or anti-pDC-SIGN mAb. Our results indicate that recombinant hICAM-3-Fc enhances mRNA expression of proinflammatory cytokines and that anti-pDC-SIGN mAb inhibits mRNA expression of TNF-α and IL-1α and enhances the expression of IL-12 induced by PRRSV in MoDCs. The results will help understand the molecular mechanisms of PRRSV pathogenesis. / Ph. D.