Lacchini S, Heimann AS, Evangelista FS, Cardoso L, Silva GJ, Krieger JE. Cuff-induced vascular intima thickening is influenced by titration of the Ace gene in mice. Physiol Genomics 37: 225-230, 2009. First published March 3, 2009; doi:10.1152/physiolgenomics.90288.2008.-We tested the hypothesis that small changes in angiotensin I-converting enzyme (ACE) expression can alter the vascular response to injury. Male mice containing one, two, three, and four copies of the Ace gene with no detectable vascular abnormality or changes in blood pressure were submitted to cuff-induced femoral artery injury. Femoral thickening was higher in 3- and 4-copy mice (42.4 +/- 4.3% and 45.7 +/- 6.5%, respectively) compared with 1- and 2-copy mice (8.3 +/- 1.3% and 8.5 +/- 0.9%, respectively). Femoral ACE levels from control and injured vessels were assessed in 1- and 3-copy Ace mice, which represent the extremes of the observed response. ACE vascular activity was higher in 3- vs. 1-copy Ace mice (2.4-fold, P < 0.05) in the control uninjured vessel. Upon injury, ACE activity significantly increased in both groups [2.41-fold and 2.14-fold (P < 0.05) for 1- and 3-copy groups, respectively] but reached higher levels in 3- vs. 1-copy Ace mice (P < 0.05). Pharmacological interventions were then used as a counterproof and to indirectly assess the role of angiotensin II (ANG II) on this response. Interestingly...

Systemic injection of pilocarpine in rodents induces status epilepticus (SE) and reproduces the main characteristics of temporal lobe epilepsy (TLE). Different mechanisms are activated by SE contributing to cell death and immune system activation. We used BALB/c nude mice, a mutant that is severely immunocompromised, to characterize seizure pattern, neurochemical changes, cell death and c-Fos activation secondarily to pilocarpine-induced SE. The behavioral seizures were less severe in BALB/c nude than in BALB/c wild type mice. However, nude mice presented more tonic clonic episodes and higher mortality rate during SE. The c-Fos expression was most prominent in the caudate-putamen, CA3 (p < 0.05), dentate gyrus, entorhinal cortex (p < 0.001), basolateral nucleus of amygdala (p < 0.01) and piriform cortex (p < 0.05) of BALB/c nude mice than of BALB/c. Besides, nude mice subjected to SE presented high number of Fluorojade-B (FJB) stained cells in the piriform cortex, amygdala (p < 0.05) and hilus (p < 0.05) in comparison with BALB/c mice. A significant increase in the level of glutamate and GABA was found in the hippocampus and cortex of BALB/c mice presenting SE in comparison to controls. However, the level of glutamate was higher in the brains of BALB nude mice than in the brains of BALB/c wild type mice...

A prevalência mundial de asma na infância é alta. Alterações estruturais das vias aéreas são observadas na asma, e podem ocorrer precocemente na infância. Este estudo tem como objetivo comparar os resultados de um modelo de sensibilização alérgica, em camundongos de diferentes idades. Para tanto foram utilizados camundongos Balb/C pré-desmamados, jovens e adultos. O grupo de animais pré desmamados foram divididos em outros dois grupos (18D 18D1), sendo que ambos foram sensibilizados com duas injeções intraperitoneal (i.p.) de 10 g ovalbumina (OVA) no 5º e 7º dia de vida. Após, o primeiro grupo de camundongos pré desmamados foram submetidos a 01 (um) desafio, este consistente em receberem inalações por 3 dias consecutivos, a 3% de OVA, por 10 minutos, nos dias 14, 15 e 16. O segundo grupo de camundongos pré desmamados foram submetidos 02 (dois) desafios, estes nos dias 09, 10 e 11; e 14, 15 e 16 dias de vida. O grupo de camundongos jovens (40D) receberam as mesmas inalações nos dias 22 a 24 e depois nos dias 36 a 38. Um quarto grupo de camundongos, denominados adultos (100D), foram sensibilizados com 10 g OVA i.p. nos dias 60 e 62 de vida; e também recebendo inalações por 3 dias consecutivos a 3% de OVA, por 10 minutos...

Th1 cells, in cooperation with activated macrophages, are required to overcome Yersinia enterocolitica infection in mice. The pathway macrophages utilize to metabolize arginine can alter the outcome of inflammation in different ways. The objective of this study was to verify the pattern of macrophages activation in Y. enterocolitica infection of BALB/c (Yersinia-susceptible) and C57BL/6 (Yersinia-resistant) mice. Both strains of mice were infected with Y. enterocolitica O:8 WA 2707. Peritoneal macrophages and spleen cells were obtained on the 1st, 3rd and 5th day post-infection. The iNOS and the arginase activities were assayed in supernatants of macrophage cultures, by measuring their NO/citrulline and ornithine products, respectively. TGFβ-1 production was also assayed. The Th1 and Th2 responses were evaluated in supernatants of lymphocyte cultures, by IFN-γ and IL-4 production. Our results showed that in the early phase of Y. enterocolitica infection (1st and 3rd day), the macrophages from C57BL/6 mice produced higher levels of NO/citrulline and lower levels of ornithine than macrophages from BALB/c mice. The infection with Y. enterocolitica leads to an increase in the TGF-β1 and IL-4 production by BALB/c mice and to an increase in the IFN-γ levels produced by C57BL/6 mice. These results suggest that Y. enterocolitica infection leads to the modulation of M1 macrophages in C57Bl/6 mice...

A ausência da distrofina em fibras musculares de camundongos mdx e na Distrofia Muscular de Duchenne (DMD) provoca ruptura no sarcolema, aumento no influxo de cálcio e conseqüente degeneração muscular. Neste trabalho verificamos os efeitos dos bloqueadores de canais de cálcio diltiazem e verapamil na degeneração/regeneração do músculo distrófico de camundongos mdx. Camundongos mdx (n=32; 18 dias de vida pós-natal) receberam diariamente injeção intraperitoneal de diltiazem (n=16; 72 mg/kg) ou verapamil (n=16; 25 mg/kg) por 18 dias. Após este período os músculos esternomastóide, diafragma, tibial anterior e coração foram retirados. Animais mdx controle (n=16) foram injetados com solução salina. Ambas drogas diminuíram significativamente os níveis séricos de creatina quinase (mdx tratado com salina: 573±245 U/l, animais tratado com diltiazem: 161±53*U/l e animais tratados com verapamil: 217±57*U/l; média±desvio padrão, *p<0,05 comparados a animais tratados com salina, teste t de Student). A quantificação de cálcio total, por espectrômetro de emissão óptica em plasma, foi 173-475% maior em músculos do mdx comparado a músculos de animais controles não-distróficos C57Bl/10. Verapamil e diltiazem reduziram a concentração de cálcio total apenas no diafragma (diltiazem: 229 mg de cálcio/kg versus salina: 295mg de cálcio/kg; p=0...

Round holes in the ears of MRL mice tend to close with characteristics of regeneration believed to be absent in other mouse strains (e.g., C57BL/6). We evaluated the kinetics and the histopathology of ear wound closure in young (8 weeks old) C57BL/6 and BALB/c mice. We also used middle-aged (40 weeks old) C57BL/6 mice to evaluate the influence of aging on this process. A circular through-and-through hole was made in the ear, photographs were taken at different times after injury and wound area was measured with digital analysis software. The percentages of closed area measured on day 100 were: 23.57 ± 8.66% for young BALB/c mice, 56.47 ± 7.39% for young C57BL/6 mice, and 75.31 ± 23.65% for middle-aged C57BL/6 mice. Mice were sacrificed on days 1, 3, 5, 25, 44, and 100 for histological evaluation with hematoxylin and eosin, Gomori’s trichrome, periodic acid-Schiff, or picrosirius red staining. In young mice of both strains, healing included re-epithelialization, chondrogenesis, myogenesis, and collagen deposition. Young C57BL/6 and BALB/c mice differed in the organization of collagen fibers visualized using picrosirius-polarization. Sebaceous glands and hair follicles regenerated and chondrogenesis was greater in young C57BL/6 mice. In middle-aged C57BL/6 mice all aspects of regeneration were depressed. The characteristics of regeneration were present during ear wound healing in both young BALB/c and young C57BL/6 mice although they differed in intensity and pattern. Greater ear wound closure in middle-aged C57BL/6 mice was not correlated with regeneration.

BACKGROUND: Helicobacter pylori a primary cause of gastritis and peptic ulcer disease, is associated with increased production of reactive oxygen species within the gastric mucosa. Metallothionein (MT), a low-molecular-weight, cysteine-rich, metal-binding ligand, has been shown to sequester reactive oxygen species and reduce tissue damage. This study investigates the role of MT in H. pylori-induced gastritis in mice. MATERIALS AND METHODS: Control (MT+/+) and MT-null (MT-/-) mice were inoculated with either 1 x 108H. pylori or H. felis, and were infected for 4, 8 and 16 weeks or 8 weeks, respectively. H. pylori load was determined by culture. Myloperoxidase activity and MT levels were also determined. RESULTS: The stomachs of H. felis-infected mice were more severely inflamed than those of H. pylori-infected mice. H. felis-induced gastritis was more severe (p =.003) in MT-/- than in MT+/+ mice. MT-/- mice also had higher (60%; p <.05) H. pylori loads than MT+/+ mice 4 weeks after infection but not 8 or 16 weeks after infection. Myloperoxidase activity with H. pylori was similar between MT+/+ and MT-/- mice. Thirty-three per cent greater (p <.05) myloperoxidase activity was observed in MT-/- than in MT+/+ mice infected with H. felis. In MT+/+ mice infected with H. pylori...

Interleukin 5 is expressed in type 2 T lymphocytes and has a key role in driving the differentiation, recruitment and activation of eosinophils. Mice with a null mutation in the interleukin 5 gene (IL-5 -/- mice) have altered type 2 immune responses and severely depleted eosinophil populations. In the present study, the effect of interleukin 5 deficiency on the abundant population of eosinophils present in the female reproductive tract was investigated, and the reproductive performance in C57Bl/6 IL-5 -/- mice was measured. Endometrial eosinophils, detected on the basis of their endogenous peroxidase activity, were reduced in number by four-sevenfold during the oestrous cycle and in early pregnancy in IL-5 -/- mice. Eosinophils present in the cervix and decidual tissues at the time of parturition were similarly diminished. The temporal fluctuations in eosinophil recruitment and localization within these tissues were otherwise unchanged, indicating that interleukin 5 is not a necessary chemotactic agent in the female reproductive tract. Oestrous cycles were moderately greater in duration in IL-5 -/- mice (mean +/- SD = 5.6 +/- 1.0 days in IL-5 -/- mice versus 5.0 +/- 0.8 days in IL-5 +/+ mice), owing to an extended period in oestrus (2.7 +/- 0.9 days per cycle in IL-5 -/- mice versus 1.8 +/- 0.7 in IL-5 +/+ mice). The interval between placing females with males and the finding of copulatory plugs was reduced significantly in interleukin 5-deficient mice. Implantation rates and subsequent fetal development were comparable in IL-5 -/- and IL-5 +/+ mice...

The accumulation of eosinophils is a common feature of allergic airway inflammation and correlates with disease severity. In an ovalbumin (OVA)-induced murine model of allergic lung disease, CBA/Ca mice develop much lower levels of lung eosinophilia, lung oedema, mucus hypersecretion and airways obstruction than BALB/c and C57BL/6 strains. In this study these strains have been examined to identify mechanisms that control the recruitment and survival of eosinophils in the allergic lung. Following immunization with OVA, CBA/Ca mice developed a robust systemic allergic response, with high levels of total and OVA-specific IgE and increases in peripheral blood eosinophils. Lung eotaxin-1 levels and expression of CD18 on eosinophils recovered by bronchoalveolar lavage (BAL) were least pronounced in CBA/Ca mice, whereas mRNA for L-selectin was highest in eosinophils from C57BL/6 mice. Apoptosis of BAL eosinophils ex vivo was most pronounced in the CBA/Ca strain. BALB/c mice expressed the highest levels of the eosinophil growth and survival factor interleukin (IL)-5 in the lungs and BAL eosinophils from these animals expressed more of the anti-apoptotic proteins Bcl-xL and Bcl-2 than cells from the other strains. A combination of lower levels of recruitment and rapid apoptosis may therefore limit the accumulation of eosinophils and pathology in the lungs of CBA/Ca mice. In addition...

We used mast cell-engrafted genetically mast cell-deficient C57BL/6-Kit(W-sh/W-sh) mice to investigate the roles of mast cells and mast cell-derived tumor necrosis factor in two models of severe bacterial infection. In these mice, we confirmed findings derived from studies of mast cell-deficient WBB6F(1)-Kit(W/W-v) mice indicating that mast cells can promote survival in cecal ligation and puncture (CLP) of moderate severity. However, we found that the beneficial role of mast cells in this setting can occur independently of mast cell-derived tumor necrosis factor. By contrast, using mast cell-engrafted C57BL/6-Kit(W-sh/W-sh) mice, we found that mast cell-derived tumor necrosis factor can increase mortality during severe CLP and can also enhance bacterial growth and hasten death after intraperitoneal inoculation of Salmonella typhimurium. In WBB6F(1)-Kit(W-sh/W-sh) mice, mast cells enhanced survival during moderately severe CLP but did not significantly change the survival observed in severe CLP. Our findings in three types of genetically mast cell-deficient mice thus support the hypothesis that, depending on the circumstances (including mouse strain background, the nature of the mutation resulting in a mast cell deficiency, and type and severity of infection)...

Yersinia pestis, the causative agent of plague, has been well studied at the molecular and genetic levels, but little is known about the role that host genes play in combating this highly lethal pathogen. We challenged several inbred strains of mice with Y. pestis and found that BALB/cJ mice are highly resistant compared to susceptible strains such as C57BL/6J. This resistance was observed only in BALB/cJ mice and not in other BALB/c substrains. Compared to C57BL/6J mice, the BALB/cJ strain exhibited reduced bacterial burden in the spleen and liver early after infection as well as lower levels of serum interleukin-6. These differences were evident 24 h postinfection and became more pronounced with time. Although a significant influx of neutrophils in the spleen and liver was exhibited in both strains, occlusive fibrinous thrombi resulting in necrosis of the surrounding tissue was observed only in C57BL/6J mice. In an effort to identify the gene(s) responsible for resistance, we measured total splenic bacteria in 95 F2 mice 48 h postinfection and performed quantitative trait locus mapping using 58 microsatellite markers spaced throughout the genome. This analysis revealed a single nonrecessive plague resistance locus, designated prl1 (plague resistance locus 1)...

Congenital dysfunction of the hypothalamic-pituitary (HP) axis occurs in approximately one birth per 2,200 and is associated with a broad range of common disease states including impaired growth (short stature), infertility, hypogonadism poor responses to stress and slow metabolism (Pescovitz and Eugster, 2004). Although, a number of genes have been linked to diseases of the HP axis, the genetic cause in many patients remains unknown. This thesis examines two aspects of HP axis development and function. The first aim was to identify Sox3 targets by examining gene expression differences between three mouse lines: Sox3-null (mice lacking Sox3; loss of function), Extra-Sox3 (mice overexpressing Sox3; gain of function) and wild-type, by genome wide profiling using the Illumina BeadChip microarray platform. The second aim was to characterize the downstream effects relative to HP development in a novel recessive dwarf mouse model with pituitary hypoplasia and growth hormone (GH) deficiency, generated by N-ethyl-Nnitrosourea (ENU) mutagenesis that produces a point mutation in the gene for the enzyme tryptophanyl-tRNA synthetase (WARS). The first project (project 1) examined Sox3, the causative gene associated with Xlinked hypopituitarism (XH)...

MHCII molecules are heterodimeric cell surface proteins composed of an α and β chain. These molecules are almost exclusively expressed on thymic epithelium and antigen presenting cells (APCs) and play a central role in the development and function of CD4 T cells. Various MHC-II knockout mice have been generated including MHC-IIAα-/- (I-Aα-/-), MHC-IIAβ-/- (I-β-/-) and the double knockout (I-Aαxβ-/-). Here we report a very striking observation, namely that alphaviruses including the avirulent strain of Semliki Forest virus (aSFV), which causes asymptomatic infection in wild-type C57BL6/J (B6) mice, causes a very acute and lethal infection in I-Aα-/-, but not in I-β-/- or I-Aαxβ-/-, mice. This susceptibility to aSFV is associated with high virus titres in muscle, spleen, liver, and brain compared to B6 mice. In addition, I-Aα-/- mice show intact IFN-I responses in terms of IFN-I serum levels and IFN-I receptor expression and function. Radiation bone marrow chimeras of B6 mice reconstituted with I-Aα-/- bone marrow expressed B6 phenotype, whereas radiation chimeras of I-Aα-/- mice reconstituted with B6 bone marrow expressed the phenotype of high viral susceptibility. Virus replication experiments both in vivo and in vitro showed enhanced virus growth in tissues and cell cultures derived form I-Aα-/- compared to B6 mice. This enhanced virus replication is evident for other alpha-...

Alterations to dendritic cell (DC) progenitors in the bone marrow (BM) may contribute to long-lasting systemic immunosuppression (>28 d) following exposure of the skin of mice to erythemal UV radiation (UVR). DCs differentiated in vitro from the BM of mice 3 d after UVR (8 kJ/m2) have a reduced capacity to initiate immunity (both skin and airways) when adoptively transferred into naive mice. Studies in IL-10−/− mice suggested that UV-induced IL-10 was not significantly involved. To investigate the immune capabilities of peripheral tissue DCs generated in vivo from the BM of UV-irradiated mice, chimeric mice were established. Sixteen weeks after reconstitution, contact hypersensitivity responses were significantly reduced in mice reconstituted with BM from UV-irradiated mice (UV-chimeric). When the dorsal skin of UV-chimeric mice was challenged with innate inflammatory agents, the hypertrophy induced in the draining lymph nodes was minimal and significantly less than that measured in control-chimeric mice challenged with the same inflammatory agent. When DCs were differentiated from the BM of UV-chimeric mice using FLT3 ligand or GM-CSF + IL-4, the cells maintained a reduced priming ability. The diminished responses in UV-chimeric mice were not due to different numerical or proportional reconstitution of BM or the hematopoietic cells in blood...

Der erste Teil der Arbeit beschäftigt sich mit dem bereits von anderen Spezies bekannten altersabhängigen Veränderungen der Nierenfunktion. Untersucht wurden junge und ältere CD-1-Mäuse. An wachen Tieren im Stoffwechselkäfigversuch zeigte sich, dass die älteren CD-1-Mäuse im Vergleich zu den jungen CD-1-Mäusen einen grösseren Flüssigkeitsumsatz hatten und eine gesteigerte Elektrolytausscheidung aufwiesen. Für die Beurteilung der funktionellen renalen Reserve wurde die Hyperfiltration nach Aminosäureinfusion untersucht. Die älteren CD-1-Mäuse hatten eine niedrigere basale GFR und zeigten keine GFR-Steigerung infolge der AS-Infusion. Bei den jungen Tiere nahm die GFR durch AS-Infusion stark zu. Eine gesteigerte Natriumausscheidung und Diurese nach Aminosäuregabe war bei jungen und älteren Tieren zu beobachten, bei den älteren CD-1-Mäusen jedoch nur in abgeschwächter Form. Der zweite Teil der Arbeit untersucht die Bedeutung des D3-Rezeptors für die renale Hämodynamik und Ausscheidungsfunktion bei D3 (-/-) Mäusen und Wildtypmäusen. Die Basalwerte der D3 (-/-) Mäusen in wachem Zustand im Stoffwechselkäfig liessen keine Unterschiede gegenüber den Wildtyptieren erkennen. Sie zeigten sogar die Tendenz, mehr Natrium auszuscheiden als die Wildtyptiere. Diese Beobachtung wurde durch weitere Versuche mit einer oralen NaCl-Beladung von 1% bzw. 4% bestätigt. Auch hier konnte kein Defizit in der Menge und der Geschwindigkeit der Natriumausscheidung bei D3 knock-out Mäusen gegenüber den Wildtypmäusen beobachtet werden. Im Vergleich zu den Wildtyptieren büssten die D3 (-/-) Mäuse durch den Verlust des D3-Rezeptors ihre Fähigkeit zur suffizienten Elektrolyt- und Volumenausscheidung nicht ein. Um die Bedeutung des D3-Rezeptors für die renale Hämodynamik zu untersuchen...

In verschiedenen tierexperimentellen Studien konnte gezeigt werden, dass das dopaminerge System an der Regulation der renalen Hämodynamik und der Tubulusfunktion beteiligt ist. Die zu Beginn eines Diabetes mellitus auftretende glomeruläre Hyperfiltration der Niere stellt einen Risikofaktor für die Entwicklung einer diabetischen Nephropathie dar. In der vorliegenden Arbeit wurde untersucht, welchen Einfluss der Dopamin D3 Rezeptor auf die glomeruläre Hyperfiltration, die renale Natriumausscheidung und damit auch das Blutdruckverhalten bei Mäusen mit durch Streptozotocin (einmalig 120 mg/kg, i.p.) erzeugtem Diabetes mellitus hat. Hierzu wurde an wachen Dopamin D3 Rezeptor Knockout Mäusen (KO) und den entsprechenden Wildtyptieren (WT), die einen funktionell aktiven Dopamin D3 Rezeptor aufweisen, Schwanzblutdruckmessungen sowie Stoffwechselkäfig (SWK)-Versuche durchgeführt. An narkotisierten Tieren wurde in Clearance-experimenten die glomeruläre Filtrationsrate, das Urinzeitvolumen und die renale Natriumausscheidung bestimmt. Die Untersuchungen wurden an nichtdiabetischen (CON), nicht behandelten diabetischen (DM) und mit Insulin behandelten (LIN-DM) Mäusen nach vorgegebenem Zeitschema innerhalb von 14-17 Tagen nach Induktion des Diabetes mellitus durchgeführt. Der gemessene systolische Blutdruck war unabhängig von der diabetischen Stoffwechsellage in allen Versuchsgruppen ähnlich. Die KO Tiere zeigten gegenüber den WT Tieren keine signifikanten Unterschiede. In den SWK-Versuchen waren bei den DM Mäusen gegenüber den CON Tieren eine signifikante Polyphagie...

Diabetes mellitus ist eine weltweit anzutreffende Stoffwechselstörung, die auf Grund von Beta-Zelldysfunktion und Insulinresistenz zu chronischer Hyperglykämie und in den Spätfolgen zu mikro- und makrovaskulären Schäden führt. Die Proteinkinase C Delta zählt zu den neuen Isoformen der PKC und fällt dadurch auf, dass ihre proapoptotische Wirkung vielfach nachgewiesen werden konnte. Als Reaktion auf diverse apoptotische Stimuli wird PKCDelta im Kern durch Caspase 3 gespalten, wobei das katalytisch aktive Fragment DeltaCF entsteht, welches für die Ausführung der Apoptose notwendig ist. Insbesondere konnte auch eine Rolle der PKCdelta in der Vermittlung von Interleukin-1Beta induzierter Apoptose in Beta-Zellen gezeigt werden. Ebenso ist allgemein akzeptiert, dass Fettsäuren in Beta-Zellen Apoptose auslösen. Zum einen wurde zwar gezeigt, dass Fettsäuren PKCDelta aktivieren, zum anderen hat aber die Runterregulierung der PKCDelta durch Langzeitbehandlung mit PMA (Phorbol-12-myristat-13-acetat) die Palmitat-induzierte Apoptose nicht verhindert. Auf Grund der immer noch bestehenden Unklarheit über die Rolle und Funktion der PKCDelta in der Beta-Zelle wurde in dieser Studie die Insulinsekretion und die Beta-Zellmasse in PKCDelta transgenen Mäusen untersucht. Zum einen wurde eine transgene Maus genutzt...

Excess salt intake increases blood pressure particularly during states of hyperinsulinism and insulin resistance. Insulin is presumably effective through activation of ENaC. Excess salt intake further decreases peripheral glucose uptake thus impairing glucose tolerance. Stimulation of both, the epithelial Na+ channel ENaC and of cellular glucose uptake involves phosphatidylinositide 3-kinase (PI-3K) which signals through protein kinase B (Akt/PKB) and all three members of the serum and glucocorticoid inducible kinase (SGK) family of kinases SGK1, SGK2 and SGK3. All three kinases have been previously shown to modify a variety of transporters including ENaC and the glucose transporter SGLT1. To explore the role of SGK1 in salt sensitive hypertension and peripheral glucose uptake, experiments were performed in male or female SGK1 knockout mice (sgk1-/-) and their wild type littermates (sgk1+/+) which were subjected to standard diet, high-fat diet, high fructose diet or dexamethasone treatment and allowed free access to either tap water (control-salt) or 1% saline (high-salt). Under control diet fluid intake, blood pressure, urinary flow rate and urinary Na+, K+, Cl- excretion were similar in sgk1-/- and sgk1+/+mice, plasma aldosterone concentration was however significantly higher in sgk1-/- (1.22 ± 0.18 ng/ml) than in sgk1+/+mice (0.57 ± 0.11 ng/ml). Under standard diet...

Alterações no metabolismo energético mitocondrial promovidas por proteínas desacopladoras (UCPs) são frequentemente encontradas em desordens metabólicas. Recentemente demonstramos que camundongos hipertrigliceridêmicos (HTG) apresentam uma respiração mitocondrial de repouso elevada, não relacionada a UCPs. Neste trabalho, nós elucidamos o mecanismo responsável por esta elevação da respiração de repouso e demonstramos algumas conseqüências dessa resposta mitocondrial à hiperlipidemia no fígado e no metabolismo corporal total. Resultados: Mitocôndrias isoladas de fígados e de células mononucleares de baço de camundongos HTG apresentaram velocidades respiratórias elevadas comparadas aos camundongos controles. Mudanças no consumo de oxigênio em mitocôndrias de fígados de camundongos HTG foram sensíveis a ATP, diazóxido e ácido 5-hidroxidecanóico (5-HD) indicando que o consumo pode ser atribuído à atividade dos canais de K+ sensíveis a ATP (mitoKATP). Do mesmo modo, as mitocôndrias HTG apresentaram um maior inchamento na presença de íons K+, sensível aos agonistas e antagonistas do mitoKATP. Além disso, a ligação de glibenclamida marcada às mitocôndrias indica que os camundongos HTG expressaram maiores quantidades de receptores de sulfoniluréias...

MHCII molecules are heterodimeric cell surface proteins composed of an α and β chain. These molecules are almost exclusively expressed on thymic epithelium and antigen presenting cells (APCs) and play a central role in the development and function of CD4 T cells. Various MHC-II knockout mice have been generated including MHC-IIAα(-/-) (I-Aα(-/-)), MHC-IIAβ(-/-) (I-β(-/-)) and the double knockout (I-Aαxβ(-/-)). Here we report a very striking observation, namely that alphaviruses including the avirulent strain of Semliki Forest virus (aSFV), which causes asymptomatic infection in wild-type C57BL6/J (B6) mice, causes a very acute and lethal infection in I-Aα(-/-), but not in I-β(-/-) or I-Aαxβ(-/-), mice. This susceptibility to aSFV is associated with high virus titres in muscle, spleen, liver, and brain compared to B6 mice. In addition, I-Aα(-/-) mice show intact IFN-I responses in terms of IFN-I serum levels and IFN-I receptor expression and function. Radiation bone marrow chimeras of B6 mice reconstituted with I-Aα(-/-) bone marrow expressed B6 phenotype, whereas radiation chimeras of I-Aα(-/-) mice reconstituted with B6 bone marrow expressed the phenotype of high viral susceptibility. Virus replication experiments both in vivo and in vitro showed enhanced virus growth in tissues and cell cultures derived form I-Aα(-/-) compared to B6 mice. This enhanced virus replication is evident for other alpha-...