Autoimmune regulator (AIRE) contributes to Dectin-1-induced TNF-alpha production and complexes with caspase recruitment domain-containing protein 9 (CARD9), spleen tyrosine kinase (Syk), and Dectin-1

Background: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome is a complex immunologic disease caused by mutation of the autoimmune regulator (AIRE) gene. Autoimmunity in patients with APECED syndrome has been shown to result from deficiency of AIRE function in transcriptional regulation of thymic peripheral tissue antigens, which leads to defective T-cell negative selection. Candidal susceptibility in patients with APECED syndrome is thought to result from aberrant adaptive immunity. Objective: To determine whether AIRE could function in anticandidal innate immune signaling, we investigated an extrathymic role for AIRE in the immune recognition of beta-glucan through the Dectin-1 pathway, which is required for defense against Candida species. Methods: Innate immune signaling through the Dectin-1 pathway was assessed in both PBMCs from patients with APECED syndrome and a monocytic cell line. Subcellular localization of AIRE was assessed by using confocal microscopy. Results: PBMCs from patients with APECED syndrome had reduced TNF-alpha responses after Dectin-1 ligation but in part used a Raf-1-mediated pathway to preserve function. In the THP-1 human monocytic cell line, reducing AIRE expression resulted in significantly decreased TNF-a release after Dectin-1 ligation. AIRE formed a transient complex with the known Dectin-1 pathway components phosphorylated spleen tyrosine kinase and caspase recruitment domain-containing protein 9 after receptor ligation and localized with Dectin-1 at the cell membrane. Conclusion: AIRE can participate in the Dectin-1 signaling pathway, indicating a novel extrathymic role for AIRE and a defect that likely contributes to fungal susceptibility in patients with APECED syndrome. (J Allergy Clin Immunol 2012;129:464-72.)

Acute ethanol intake induces superoxide anion generation and mitogen-activated protein kinase phosphorylation in rat aorta: A role for angiotensin type 1 receptor

Ethanol intake is associated with increase in blood pressure, through unknown mechanisms. We hypothesized that acute ethanol intake enhances vascular oxidative stress and induces vascular dysfunction through renin-angiotensin system (RAS) activation. Ethanol (1 g/kg; p.o. gavage) effects were assessed within 30 min in male Wistar rats. The transient decrease in blood pressure induced by ethanol was not affected by the previous administration of losartan (10 mg/kg; p.o. gavage), a selective ATI receptor antagonist. Acute ethanol intake increased plasma renin activity (PRA), angiotensin converting enzyme (ACE) activity, plasma angiotensin I (ANG I) and angiotensin II (ANG II) levels. Ethanol induced systemic and vascular oxidative stress, evidenced by increased plasma thiobarbituric acid-reacting substances (TBARS) levels, NAD(P) H oxidase-mediated vascular generation of superoxide anion and p47phox translocation (cytosol to membrane). These effects were prevented by losartan. Isolated aortas from ethanol-treated rats displayed increased p38MAPK and SAPK/JNK phosphorylation. Losartan inhibited ethanol-induced increase in the phosphorylation of these kinases. Ethanol intake decreased acetylcholine-induced relaxation and increased phenylephrine-induced contraction in endothelium-intact aortas. Ethanol significantly decreased plasma and aortic nitrate levels. These changes in vascular reactivity and in the end product of endogenous nitric oxide metabolism were not affected by losartan. Our study provides novel evidence that acute ethanol intake stimulates RAS activity and induces vascular oxidative stress and redox-signaling activation through AT(1)-dependent mechanisms. These findings highlight the importance of RAS in acute ethanol-induced oxidative damage. (c) 2012 Elsevier Inc. All rights reserved.

A gymnosperm homolog of SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE-1 (SERK1) is expressed during somatic embryogenesis

The physiological and molecular processes controlling zygotic and somatic embryo development in angiosperms are mediated by a hierarchically organized program of gene expression. Despite the overwhelming information available about the molecular control of the embryogenic processes in angiosperms, little is known about these processes in gymnosperms. Here we describe the cloning and characterization of the expression pattern of the Araucaria angustifolia putative homolog of a SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) gene family member, designated as AaSERK1. The Araucaria AaSERK1 gene encodes a leucine-rich repeat receptor-like kinase showing significant similarity to angiosperm homologs of SERK1, known to be involved in early somatic and zygotic embryogenesis. Accordingly, RT-PCR results showed that AaSERK1 is preferentially expressed in Araucaria embryogenic cell cultures. Additionally, in situ hybridization results showed that AaSERK1 transcripts initially accumulate in groups of cells at the periphery of the embryogenic calli and then are restricted to the developing embryo proper. Our results indicate that AaSERK1 might have a role during somatic embryogenesis in Araucaria, suggesting a potentially conserved mechanism, involving SERK-related leucine-rich repeat receptor-like kinases, in the embryogenic processes among all seed plants.

Spironolactone prevents alterations associated with cardiac hypertrophy produced by isoproterenol in rats: involvement of serum- and glucocorticoid-regulated kinase type 1

Persistent beta-adrenergic receptor stimulation with isoproterenol is associated with cardiac hypertrophy as well as cardiac synthesis of angiotensin II. Serum- and glucocorticoid-regulated kinase type 1 (SGK-1) is a key mediator in structural, functional and molecular cardiac effects of aldosterone in rats. This study was designed to investigate the cardiac effects of the mineralocorticoid receptor antagonist spironolactone on the response to isoproterenol treatment in rats, as well as the involvement of the main mediator of cellular aldosterone action, SGK-1, in the heart. Male Wistar rats received isoproterenol (3 mg kg-1 day-1) or vehicle for 15 days. Half of the animals in each group were simultaneously treated with spironolactone (200 mg kg-1 day-1). Systolic and diastolic blood pressures were not significantly different among groups. Treatment with spironolactone normalized the increased left ventricular end-diastolic pressure observed in isoproterenol-treated rats. Isoproterenol treatment induced cardiac hypertrophy and increased collagen content, both of which were normalized by spironolactone treatment. The mRNA levels of transforming growth factor beta, connective tissue growth factor, matrix metalloprotease 2, matrix metalloprotease inhibitor 2, tumour necrosis factor a, interleukin 1 beta, p22phox and xanthine dehydrogenase were increased (P < 0.05) in isoproterenol-treated rats, and this effect was prevented by spironolactone (P < 0.05). Spironolactone also reduced the elevated SGK-1 expression in isoproterenol-treated rats. The observed reduction of the principal mediator of aldosterone cellular actions, SGK-1, by spironolactone in hearts from isoproterenol-treated rats suggests a role of mineralocorticoids in the cardiac hypertrophy, fibrosis, inflammation, oxidation and diastolic dysfunction induced by isoproterenol treatment in rats.

Loss of the anorexic response to systemic 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside administration despite reducing hypothalamic AMP-activated protein kinase phosphorylation in insulin-deficient rats

This study tested whether chronic systemic administration of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) could attenuate hyperphagia, reduce lean and fat mass losses, and improve whole-body energy homeostasis in insulin-deficient rats. Male Wistar rats were first rendered diabetic through streptozotocin (STZ) administration and then intraperitoneally injected with AICAR for 7 consecutive days. Food and water intake, ambulatory activity, and energy expenditure were assessed at the end of the AICAR-treatment period. Blood was collected for circulating leptin measurement and the hypothalami were extracted for the determination of suppressor of cytokine signaling 3 (SOCS3) content, as well as the content and phosphorylation of AMP-kinase (AMPK), acetyl-CoA carboxylase (ACC), and the signal transducer and activator of transcription 3 (STAT3). Rats were thoroughly dissected for adiposity and lean body mass (LBM) determinations. In non-diabetic rats, despite reducing adiposity, AICAR increased (∼1.7-fold) circulating leptin and reduced hypothalamic SOCS3 content and food intake by 67% and 25%, respectively. The anorexic effect of AICAR was lost in diabetic rats, even though hypothalamic AMPK and ACC phosphorylation markedly decreased in these animals. Importantly, hypothalamic SOCS3 and STAT3 levels remained elevated and reduced, respectively, after treatment of insulin-deficient rats with AICAR. Diabetic rats were lethargic and displayed marked losses of fat and LBM. AICAR treatment increased ambulatory activity and whole-body energy expenditure while also attenuating diabetes-induced fat and LBM losses. In conclusion, AICAR did not reverse hyperphagia, but it promoted anti-catabolic effects on skeletal muscle and fat, enhanced spontaneous physical activity, and improved the ability of rats to cope with the diabetes-induced dysfunctional alterations in glucose metabolism and whole-body energy homeostasis.

Double-Stranded RNA-Activated Protein Kinase Is a Key Modulator of Insulin Sensitivity in Physiological Conditions and in Obesity in Mice

The molecular integration of nutrient-and pathogen-sensing pathways has become of great interest in understanding the mechanisms of insulin resistance in obesity. The double-stranded RNA-dependent protein kinase (PKR) is one candidate molecule that may provide cross talk between inflammatory and metabolic signaling. The present study was performed to determine, first, the role of PKR in modulating insulin action and glucose metabolism in physiological situations, and second, the role of PKR in insulin resistance in obese mice. We used Pkr(-/-) and Pkr(+/+) mice to investigate the role of PKR in modulating insulin sensitivity, glucose metabolism, and insulin signaling in liver, muscle, and adipose tissue in response to a high-fat diet. Our data show that in lean Pkr(-/-) mice, there is an improvement in insulin sensitivity, and in glucose tolerance, and a reduction in fasting blood glucose, probably related to a decrease in protein phosphatase 2A activity and a parallel increase in insulin-induced thymoma viral oncogene-1 (Akt) phosphorylation. PKR is activated in tissues of obese mice and can induce insulin resistance by directly binding to and inducing insulin receptor substrate (IRS)-1 serine307 phosphorylation or indirectly through modulation of c-Jun N-terminal kinase and inhibitor of kappa B kinase beta. Pkr(-/-) mice were protected from high-fat diet-induced insulin resistance and glucose intolerance and showed improved insulin signaling associated with a reduction in c-Jun N-terminal kinase and inhibitor of kappa B kinase beta phosphorylation in insulin-sensitive tissues. PKR may have a role in insulin sensitivity under normal physiological conditions, probably by modulating protein phosphatase 2A activity and serine-threonine kinase phosphorylation, and certainly, this kinase may represent a central mechanism for the integration of pathogen response and innate immunity with insulin action and metabolic pathways that are critical in obesity. (Endocrinology 153:5261-5274, 2012)

Gene Expression in Bovine Oocytes and Cumulus Cells After Meiotic Inhibition with the Cyclin-Dependent Kinase Inhibitor Butyrolactone I

Contents The aim of this study was to determine the effect of temporary inhibition of meiosis using the cyclin-dependent kinase inhibitor butyrolactone I (BLI) on gene expression in bovine oocytes and cumulus cells. Immature bovine cumulusoocyte complexes (COCs) were assigned to groups: (i) Control COCs collected immediately after recovery from the ovary or (ii) after in vitro maturation (IVM) for 24 h, (iii) Inhibited COCs collected 24 h after incubation with 100 mu m BLI or (iv) after meiotic inhibition for 24 h followed by IVM for a further 22 h. For mRNA relative abundance analysis, pools of 10 denuded oocytes and respective cumulus cells were collected. Transcripts related to cell cycle regulation and oocyte competence were evaluated in oocytes and cumulus cells by quantitative real-time PCR (qPCR). Most of the examined transcripts were downregulated (p < 0.05) after IVM in control and inhibited oocytes (19 of 35). Nine transcripts remained stable (p > 0.05) after IVM in control oocytes; only INHBA did not show this pattern in inhibited oocytes. Seven genes were upregulated after IVM in control oocytes (p < 0.05), and only PLAT, RBP1 and INHBB were not upregulated in inhibited oocytes after IVM. In cumulus cells, six genes were upregulated (p < 0.05) after IVM and eight were downregulated (p < 0.05). Cells from inhibited oocytes showed the same pattern of expression regarding maturation profile, but were affected by the temporary meiosis inhibition of the oocyte when the same maturation stages were compared between inhibited and control groups. In conclusion, changes in transcript abundance in oocytes and cumulus cells during maturation in vitro were mostly mirrored after meiotic inhibition followed by maturation.

Focal adhesion kinase governs cardiac concentric hypertrophic growth by activating the AKT and mTOR pathways

The heart responds to sustained overload by hypertrophic growth in which the myocytes distinctly thicken or elongate on increases in systolic or diastolic stress. Though potentially adaptive, hypertrophy itself may predispose to cardiac dysfunction in pathological settings. The mechanisms underlying the diverse morphology and outcomes of hypertrophy are uncertain. Here we used a focal adhesion kinase (FAK) cardiac-specific transgenic mice model (FAK-Tg) to explore the function of this non-receptor tyrosine kinase on the regulation of myocyte growth. FAK-Tg mice displayed a phenocopy of concentric cardiac hypertrophy, reflecting the relative thickening of the individual myocytes. Moreover, FAK-Tg mice showed structural, functional and molecular features of a compensated hypertrophic growth, and preserved responses to chronic pressure overload. Mechanistically, FAK overexpression resulted in enhanced myocardial FAK activity, which was proven by treatment with a selective FAK inhibitor to be required for the cardiac hypertrophy in this model. Our results indicate that upregulation of FAK does not affect the activity of Src/ERK1/2 pathway, but stimulated signaling by a cascade that encompasses PI3K, AKT, mTOR, S6K and rpS6. Moreover, inhibition of the mTOR complex by rapamycin extinguished the cardiac hypertrophy of the transgenic FAK mice. These findings uncover a unique role for FAK in regulating the signaling mechanisms that governs the selective myocyte growth in width, likely controlling the activity of PI3K/AKT/mTOR pathway, and suggest that FAK activation could be important for the adaptive response to increases in cardiac afterload. This article is part of a Special Issue entitled "Local Signaling in Myocytes". (C) 2011 Elsevier Ltd. All rights reserved.

In vivo hydroquinone exposure impairs MCP-1 secretion and monocyte recruitment into the inflamed lung

Alveolar macrophages (AMs) are important cells in the resolution of the inflammatory process and they come into direct contact with inhaled pollutants. Hydroquinone (HQ) is an environmental pollutant and a component of cigarette smoke that causes immunosuppressive effects. In the present work, we showed that mice exposed to low levels of aerosolized HQ (25 ppm; 1 h/day/5 days) presented impaired mononuclear cell migration to the lipopolysaccharide (LPS)-inflamed lung. This may have been due to reduced monocyte chemoattractant protein-1 (MCP-1) secretion into bronchoalveolar lavage fluid (BALF), and it was not related to alterations to mononuclear cell mobilization into the blood or adhesion molecules expression on mononuclear cell membranes. Corroborating the actions of HQ on MCP-1 secretion, reduced MCP-1 concentrations were also found in the supernatant of ex vivo AM and tracheal tissue collected from HQ-exposed mice. A direct action of HQ on MCP-1 secretion, resulting from impaired gene synthesis, was verified by in vitro incubation of naive AMs or tracheal tissue with HQ. The role of reduced levels of MCP-1 in the BALF on monocyte migration was analysed in the human monocytic lineage THP-1 in in vitro chemotaxis assays, which showed that the reduced concentrations of MCP-1 found in the BALF or cell supernatants from HQ-exposed mice impaired cell migration. Considering the fact that MCP-1 presents a broad spectrum of actions on pathophysiological conditions and that resident mononuclear cells are involved in lung tissue homeostasis and in immune host defence, the mechanism of HQ toxicity presented herein might be relevant to the genesis of infectious lung diseases in smokers and in inhabitants of polluted areas. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

Kaurenoic Acid from Sphagneticola trilobata Inhibits Inflammatory Pain: Effect on Cytokine Production and Activation of the NO-Cyclic GMP-Protein Kinase G-ATP-Sensitive Potassium Channel Signaling Pathway

Kaurenoic acid [ent-kaur-16-en-19-oic acid (1)] is a diterpene present in several plants including Sphagneticola trilobata. The only documented evidence for its antinociceptive effect is that it inhibits the writhing response induced by acetic acid in mice. Therefore, the analgesic effect of 1 in different models of pain and its mechanisms in mice were investigated further. Intraperitoneal and oral treatment with 1 dose-dependently inhibited inflammatory nociception induced by acetic acid. Oral treatment with 1 also inhibited overt nociception-like behavior induced by phenyl-p-benzoquinone, complete Freund's adjuvant (CFA), and both phases of the formalin test. Compound 1 also inhibited acute carrageenin- and PGE(2)-induced and chronic CFA-induced inflammatory mechanical hyperalgesia. Mechanistically, 1 inhibited the production of the hyperalgesic cytokines TNF-alpha and IL-1 beta. Furthermore, the analgesic effect of 1 was inhibited by L-NAME, ODQ, KT5823, and glybenclamide treatment, demonstrating that such activity also depends on activation of the NO-cyclic GMP-protein kinase G-ATP-sensitive potassium channel signaling pathway, respectively. These results demonstrate that 1 exhibits an analgesic effect in a consistent manner and that its mechanisms involve the inhibition of cytokine production and activation of the NO-cyclic GMP-protein lcinase G-ATP-sensitive potassium channel signaling pathway.

The IgA1 immune complex-mediated activation of the MAPK/ERK kinase pathway in mesangial cells is associated with glomerular damage in IgA nephropathy

IgA nephropathy (IgAN), the most common primary glomerulonephritis worldwide, has significant morbidity and mortality as 20-40% of patients progress to end-stage renal disease within 20 years of onset. In order to gain insight into the molecular mechanisms involved in the progression of IgAN, we systematically evaluated renal biopsies from such patients. This showed that the MAPK/ERK signaling pathway was activated in the mesangium of patients presenting with over 1 g/day proteinuria and elevated blood pressure, but absent in biopsy specimens of patients with IgAN and modest proteinuria (<1 g/day). ERK activation was not associated with elevated galactose-deficient IgA1 or IgG specific for galactose-deficient IgA1 in the serum. In human mesangial cells in vitro, ERK activation through mesangial IgA1 receptor (CD71) controlled pro-inflammatory cytokine secretion and was induced by large-molecular-mass IgA1-containing circulating immune complexes purified from patient sera. Moreover, IgA1-dependent ERK activation required renin-angiotensin system as its blockade was efficient in reducing proteinuria in those patients exhibiting substantial mesangial activation of ERK. Thus, ERK activation alters mesangial cell-podocyte crosstalk, leading to renal dysfunction in IgAN. Assessment of MAPK/ERK activation in diagnostic renal biopsies may predict the therapeutic efficacy of renin-angiotensin system blockers in IgAN. Kidney International (2012) 82, 1284-1296; doi:10.1038/ki.2012.192; published online 5 September 2012

Rho-kinase inhibition attenuates airway responsiveness, inflammation, matrix remodeling, and oxidative stress activation induced by chronic inflammation

Possa SS, Charafeddine HT, Righetti RF, da Silva PA, Almeida-Reis R, Saraiva-Romanholo BM, Perini A, Prado CM, Leick-Maldonado EA, Martins MA, Tiberio ID. Rho-kinase inhibition attenuates airway responsiveness, inflammation, matrix remodeling, and oxidative stress activation induced by chronic inflammation. Am J Physiol Lung Cell Mol Physiol 303: L939-L952, 2012. First published September 21, 2012; doi:10.1152/ajplung.00034.2012.-Several studies have demonstrated the importance of Rho-kinase in the modulation of smooth muscle contraction, airway hyperresponsiveness, and inflammation. However, the effects of repeated treatment with a specific inhibitor of this pathway have not been previously investigated. We evaluated the effects of repeated treatment with Y-27632, a highly selective Rho-kinase inhibitor, on airway hyperresponsiveness, oxidative stress activation, extracellular matrix remodeling, eosinophilic inflammation, and cytokine expression in an animal model of chronic airway inflammation. Guinea pigs were subjected to seven ovalbumin or saline exposures. The treatment with Y-27632 (1 mM) started at the fifth inhalation. Seventy-two hours after the seventh inhalation, the animals' pulmonary mechanics were evaluated, and exhaled nitric oxide (E-NO) was collected. The lungs were removed, and histological analysis was performed using morphometry. Treatment with Y-27632 in sensitized animals reduced E-NO concentrations, maximal responses of resistance, elastance of the respiratory system, eosinophil counts, collagen and elastic fiber contents, the numbers of cells positive for IL-2, IL-4, IL-5, IL-13, inducible nitric oxide synthase, matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-1, transforming growth factor-beta, NF-kappa B, IFN-gamma, and 8-iso-prostaglandin F2 alpha contents compared with the untreated group (P < 0.05). We observed positive correlations among the functional responses and inflammation, remodeling, and oxidative stress pathway activation markers evaluated. In conclusion, Rho-kinase pathway activation contributes to the potentiation of the hyperresponsiveness, inflammation, the extracellular matrix remodeling process, and oxidative stress activation. These results suggest that Rho-kinase inhibitors represent potential pharmacological tools for the control of asthma.

Identification of Novel Interaction between ADAM17 (a Disintegrin and Metalloprotease 17) and Thioredoxin-1

ADAM17, which is also known as TNF alpha-converting enzyme, is the major sheddase for the EGF receptor ligands and is considered to be one of the main proteases responsible for the ectodomain shedding of surface proteins. How a membrane-anchored proteinase with an extracellular catalytic domain can be activated by inside-out regulation is not completely understood. We characterized thioredoxin-1 (Trx-1) as a partner of the ADAM17 cytoplasmic domain that could be involved in the regulation of ADAM17 activity. We induced the overexpression of the ADAM17 cytoplasmic domain in HEK293 cells, and ligands able to bind this domain were identified by MS after protein immunoprecipitation. Trx-1 was also validated as a ligand of the ADAM17 cytoplasmic domain and full-length ADAM17 recombinant proteins by immunoblotting, immunolocalization, and solid phase binding assay. In addition, using nuclear magnetic resonance, it was shown in vitro that the titration of the ADAM17 cytoplasmic domain promotes changes in the conformation of Trx-1. The MS analysis of the cross-linked complexes showed cross-linking between the two proteins by lysine residues. To further evaluate the functional role of Trx-1, we used a heparin-binding EGF shedding cell model and observed that the overexpression of Trx-1 in HEK293 cells could decrease the activity of ADAM17, activated by either phorbol 12-myristate 13-acetate or EGF. This study identifies Trx-1 as a novel interaction partner of the ADAM17 cytoplasmic domain and suggests that Trx-1 is a potential candidate that could be involved in ADAM17 activity regulation.

Exposure of luminal membranes of LLC-PK1 cells to ANG II induces dimerization of AT(1)/AT(2) receptors to activate SERCA and to promote Ca2+ mobilization

Ferrao FM, Lara LS, Axelband F, Dias J, Carmona AK, Reis RI, Costa-Neto CM, Vieyra A, Lowe J. Exposure of luminal membranes of LLC-PK1 cells to ANG II induces dimerization of AT(1)/AT(2) receptors to activate SERCA and to promote Ca2+ mobilization. Am J Physiol Renal Physiol 302: F875-F883, 2012. First published January 4, 2012; doi:10.1152/ajprenal.00381.2011.-ANG II is secreted into the lumens of proximal tubules where it is also synthesized, thus increasing the local concentration of the peptide to levels of potential physiological relevance. In the present work, we studied the effect of ANG II via the luminal membranes of LLC-PK1 cells on Ca2+-ATPase of the sarco(endo) plasmic reticulum (SERCA) and plasma membrane (PMCA). ANG II (at concentrations found in the lumen) stimulated rapid (30 s) and persistent (30 min) SERCA activity by more than 100% and increased Ca2+ mobilization. Pretreatment with ANG II for 30 min enhanced the ANG II-induced Ca2+ spark, demonstrating a positively self-sustained stimulus of Ca2+ mobilization by ANG II. ANG II in the medium facing the luminal side of the cells decreased with time with no formation of metabolites, indicating peptide internalization. ANG II increased heterodimerization of AT(1) and AT(2) receptors by 140%, and either losartan or PD123319 completely blocked the stimulation of SERCA by ANG II. Using the PLC inhibitor U73122, PMA, and calphostin C, it was possible to demonstrate the involvement of a PLC -> DAG(PMA)-> PKC pathway in the stimulation of SERCA by ANG II with no effect on PMCA. We conclude that ANG II triggers SERCA activation via the luminal membrane, increasing the Ca2+ stock in the reticulum to ensure a more efficient subsequent mobilization of Ca2+. This first report on the regulation of SERCA activity by ANG II shows a new mechanism for Ca2+ homeostasis in renal cells and also for regulation of Ca2+-modulated fluid reabsorption in proximal tubules.

ROLE OF FOCAL ADHESION KINASE IN LUNG REMODELING OF ENDOTOXEMIC RATS

Despite significant advances in the care of critically ill patients, acute lung injury continues to be a complex problem with high mortality. The present study was designed to characterize early lipopolysaccharide (LPS)-induced pulmonary injury and small interfering RNA targeting focal adhesion kinase (FAK) as a possible therapeutic tool in the septic lung remodeling process. Male Wistar rats were assigned into endotoxemic group and control group. Total collagen deposition was performed 8, 16, and 24 h after LPS injection. Focal adhesion kinase expression, interstitial and vascular collagen deposition, and pulmonary mechanics were analyzed at 24 h. Intravenous injection of small interfering RNA targeting FAK was used to silence expression of the kinase in pulmonary tissue. Focal adhesion kinase, total collagen deposition, and pulmonary mechanics showed increased in LPS group. Types I, III, and V collagen showed increase in pulmonary parenchyma, but only type V increased in vessels 24 h after LPS injection. Focal adhesion kinase silencing prevented lung remodeling in pulmonary parenchyma at 24 h. In conclusion, LPS induced a precocious and important lung remodeling. There was fibrotic response in the lung characterized by increased amount in total and specific-type collagen. These data may explain the frequent clinical presentation during sepsis of reduced lung compliance, oxygen diffusion, and pulmonary hypertension. The fact that FAK silencing was protective against lung collagen deposition underscores the therapeutic potential of FAK targeting by small interfering RNA.