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Simple Summary: This study focuses on how Tasmanian sea-farmed Atlantic salmon respond to a natural infection with a parasite that causes amoebic gill disease (AGD), a major health issue for salmon globally. The research aimed to understand the progression of the disease by examining the salmon's gills at different stages of the outbreak and evaluating their response to freshwater treatment. The study employed both macroscopic and microscopic examinations of gills, as well as molecular tools to measure the abundance of amoebae and the expression of specific genes that indicate inflammation. Key findings showed a strong correlation between different measures of gill health and significant differences between distinct stages of AGD. After treatment, a varied response among the fish was observed, indicating that management strategies need to account for individual genetic, environmental, and health factors. The expression patterns of some inflammation-related genes highlight their potential as biomarkers for early detection of gill damage in salmon aquaculture worldwide. The results of this research are important as they can help develop better ways to detect and manage this disease early, potentially reducing losses in salmon farming and ensuring the sustainability of this vital food resource. Gill health has become a significant global challenge for Atlantic salmon (Salmo salar) aquaculture, particularly during the marine phase of farming. The increasing prevalence of gill pathologies has been linked to rising seawater temperatures, underscoring the need to evaluate existing tools for monitoring gill health and to develop novel approaches for early detection. In this study, we investigated the gill responses of commercially farmed Atlantic salmon to natural infection with Neoparamoeba perurans during an outbreak of amoebic gill disease (AGD) in Tasmania. Our focus spanned the low AGD prevalence, high AGD prevalence, and post-freshwater treatment stages of the outbreak. Evaluations of gill tissue included assessments of the gross AGD score, histopathological score, abundance of N. perurans (measured by 18S rRNA gene expression), and expression levels of inflammation-related transcripts. We demonstrated a strong correlation between different measures of AGD-related gill pathology and significant differences between distinct stages of the N. perurans outbreak. Post-treatment, fish exhibited considerable variability in their responses to the freshwater bath, highlighting the necessity for personalized management strategies that consider genetic, environmental, and health status factors. The expression patterns of angiogenin-1 (ANG1) and complement C1q tumour necrosis factor-related protein 3-like (C1QTNF3) emphasize their potential as biomarkers for early detection of gill damage in salmon aquaculture worldwide. [ABSTRACT FROM AUTHOR]

Hypertensive disorders of pregnancy are characterized by systemic and placental inflammation; however, treatment for these conditions has remained elusive. We tested whether administration of the anti-inflammatory cytokine interleukin-10 (IL-10) during pregnancy would attenuate the hypertension, endothelial dysfunction, proteinuria, and inflammation seen in pregnant DOCA/saline-treated (PDS) rats. Normal pregnant (NP) rats and PDS were given daily intraperitoneal injections of recombinant IL-10 from gestational day 13 until death on day 20. Systolic blood pressure, aortic endothelium-dependent relaxation responses, and urinary protein excretion were measured on days 13 and 20 of gestation. Fetal number and development, plasma endothelin-1 levels, serum and placental levels of IFN[gamma] and IL-10, and aortic and placental levels of platelet endothelial cell adhesion molecule (PECAM) were assessed on gestational day 20. Systolic blood pressure, aortic endothelial dysfunction, and urinary protein excretion were significantly increased at gestational day 13 in PDS rats. However, all of these were restored to NP levels following IL-10 treatment in PDS rats. IL-10 treatment also significantly increased the number of pups per litter in PDS rats and did not further affect fetal development. The beneficial effects of IL-10 in PDS rats were likely mediated by the decreased plasma levels of endothelin-1, decreased levels of circulating and placental IFN[gamma], as well as decreased aortic and placental expression of PECAM. These data demonstrate that exogenous IL-10 can normalize blood pressure and endothelial function in pregnancy-induced hypertensive rats and may be beneficial in women with hypertensive disorders of pregnancy. preeclampsia; anti-inflammatory; hypertension; endothelin-1 doi:10.1152/ajpregu.00712.2009

Studies from our laboratory demonstrated the involvement of intrinsic apoptotic signaling in hyperpermeability following hemorrhagic shock (HS). Angiopoietin 1 (Ang-1), a potent inhibitor of hyperpermeability, was recently shown to inhibit apoptosis. The purpose of our study was to determine the effectiveness of Ang-1 in attenuating HS-induced hyperpermeability and its relationship to apoptotic signaling. HS was induced in rats by withdrawing blood to reduce the mean arterial pressure to 40 mmHg for 1 h, followed by reperfusion. Mesenteric postcapillary venules were examined for changes in hyperpermeability by intravital microscopy. Mitochondrial release of second mitochondrial derived activator of caspases (smac) and cytochrome c were determined by Western blot and ELISA, respectively. Caspase-3 activity was determined by fluorometric assay. Parallel studies were performed in rat lung microvascular endothelial cell (RLMEC) monolayers, utilizing HS serum and the proapoptotic Bcl-2 homologous antagonist/killer [BAK (BH3)] peptide as inducers of hyperpermeability. In rats, Ang-I (200 ng/ml) attenuated HS-induced hyperpermeability versus the HS group (P < 0.05). Ang-1 prevented HS-induced collapse of mitochondrial transmembrane potential ([DELTA] [[PSI].sub.m]), smac and cytochrome c release, and caspase-3 activity (P < 0.05). In RLMEC monolayers, HS serum and BAK (BH3) peptide both induced hyperpermeability that was inhibited by Ang-1 (P < 0.05). Ang-1 attenuated HS and BAK (BH3) peptide-induced collapse of [DELTA][[PSI].sub.m], smac release, cytochrome c release, activation of caspase-3, and vascular hyperpermeability. In vivo, BAK (BH3) induced vascular hyperpermeability that was attenuated by Ang-1 (P < 0.05). These findings suggest that Ang-l's role in maintaining microvascular endothelial barrier integrity involves the intrinsic apoptotic signaling cascade. ischemia-reperfusion injury; microvascular hyperpermeability; smac

Hemorrhagic shock (HS) disrupts the endothelial cell barrier, resulting in microvascular hyperpermeability. Recent studies have also demonstrated that activation of the apoptotic signaling cascade is involved in endothelial dysfunction, which may result in hyperpermeability. Here we report involvement of the mitochondrial 'intrinsic' pathway in microvascular hyperpermeability following HS in rats. HS resulted in the activation of the mitochondrial intrinsic pathway, as is evident from an increase in the proapoptotic Bcl-2 family member BAK, release of mitochondrial cytochrome c into the cytoplasm, and activation of caspase-3. This, along with the in vivo transfection of the proapoptotic peptide BAK (BH3), resulted in hyperpermeability (as visualized by intravital microscopy), release of mitochondrial cytochrome c into the cytoplasm, and activation of caspase-3. Conversely, transfection of the BAK (BH3) mutant had no effect on hyperpermeability. Together, these results demonstrate involvement of the mitochondrial intrinsic apoptotic pathway in HS-induced hyperpermeability and that the attenuation of this pathway may provide an alternative strategy in preserving vascular barrier integrity. BAK; ischemia-reperfusion; protein transfection; cytochrome c; caspase-3 doi: 10.1152/ajpheart.01337.2006

Rat lung microvascular endothelial cell monolayers were exposed to donor plasma from burned rats (25% total body surface area) at 1:3 dilution for 30 min. Immunofluorescence analysis revealed that concomitant with gap formation alterations were seen in the adherens junction (AJ) proteins [beta]-catenin and vascular endothelial-cadherin. Both of these components were shown to exist in a smooth, uniform arrangement at the cell periphery in untreated cells. However, upon exposure to burn plasma, this uniformity was lost, and the AJ proteins showed a disrupted, zipper-like pattern at the cells' edge. In addition, these proteins were absent from areas of gap formation between the cells, and an increase in punctate staining throughout the cells suggests they were internalized in response to burn plasma. Measurements of both transendothelial electrical resistance and FITC-albumin flux across the cell monolayer were used to assess barrier integrity. Our study found that exposure to burn plasma rapidly caused the electrical resistance across confluent monolayers to decrease and albumin flux to increase, phenomena associated with barrier dysfunction. Furthermore, all the above responses to burn plasma were attenuated when cells were pretreated with the PKC inhibitor bisindolyl-maleimide, suggesting that PKC is required for burn-induced pulmonary endothelial dysfunction. protein kinase C; cadherin; [beta]-catenin; serine phosphorylation

Tinsley, John H., Nicole R. Teasdale, and Sarah Y. Yuan. Myosin light chain phosphorylation and pulmonary endothelial cell hyperpermeability in burns. Am J Physiol Lung Cell Mol Physiol 286: L841-L847, 2004. First published December 12, 2003; 10.1152/ ajplung.00341.2003.--Major cutaneous burns result in not only localized tissue damage but broad systemic inflammation causing organ system damage distal to the burn site. It is well recognized that many problems result from the release of inflammatory mediators that target vascular endothelial cells, causing organ dysfunction. The pulmonary microvessels are particularly susceptible to functional abnormalities as a direct consequence of exposure to burn-induced inflammatory mediators. Traditional therapeutic intervention is quite often ineffective in treating burn patients suffering from systemic problems. A possible explanation for this ineffectiveness may be that because so many mediators are released, supposedly activating numerous signaling cascades that interact with each other, targeting of upstream factors in these cascades on an individual basis becomes futile. Therefore, if an end-point effector responsible for endothelial dysfunction following burn injury could be identified, it may present a target for intervention. In this study, we identified phosphorylation of myosin light chain (MLC) as a required element of burn plasma-induced hyperpermeability across rat lung microvascular endothelial cell monolayers. In addition, pharmacological inhibition of myosin light chain kinase (MLCK) and Rho kinase as well as transfection of MLCK-inhibiting peptide blocked actin stress fiber formation and MLC phosphorylation in response to burn plasma. The results suggest that blocking MLC phosphorylation may provide therapeutic intervention in burn patients with the goal of alleviating systemic inflammation-induced endothelial dysfunction. signal transduction; permeability; pulmonary endothelium; microvasculature

The involvement of PKC, the isoforms of which are categorized into three subtypes: conventional ([alpha], [beta]I, [beta]II, and [gamma]), novel [[delta], [epsilon], [eta], and [mu] (also known as PKD), [theta]], and atypical ([zeta] and [iota]/[lambda]), in the regulation of endothelial monolayer integrity is well documented. However, isoform activity varies among different cell types. Our goal was to reveal isoform-specific PKC activity in the microvascular endothelium in response to phorbol 12-myristate 13-acetate (PMA) and diacylglycerol (DAG). Isoform activity was demonstrated by cytosol-to-membrane translocation after PMA treatment and phosphorylation of the myristoylated alanine-rich C kinase substrate (MARCKS) protein after PMA and DAG treatment. Specific isoforms were inhibited by using both antisense oligonucleotides and pharmacological agents. The data showed partial cytosol-to-membrane translocation of isoforms [alpha], [beta]I, and [epsilon] and complete translocation of PKC[delta] and PKD in response to PMA. Furthermore, antisense treatment and pharmacological studies indicated that the novel isoform PKC[delta] and PKD are both required for PMA- and DAG-induced MARCKS phosphorylation and hyperpermeability in pulmonary microvascular endothelial cells, whereas isoforms, [beta]I, and [epsilon] were dispensable with regard to these same phenomena. signal transduction; permeability: myristolated alanine-rich C kinase substrate; microvasculature; pulmonary endothelium

The hyperpermeability response of microvessels in inflammation involves complex signaling reactions and structural modifications in the endothelium. Our goal was to determine the role of Src-family kinases (Src) in neutrophil-mediated venular hyperpermeability and possible interactions between Src and endothelial barrier components. We found that inhibition of Src abolished the increases in albumin permeability caused by C5a-activated neutrophils in intact, perfused coronary venules, as well as in cultured endothelial monolayers. Activated neutrophils increased Src phosphorylation at Tyr416, which is located in the catalytic domain, and decreased phosphorylation at Tyr527 near the carboxyl terminus, events consistent with reports that phosphorylating and transforming activities of Src are upregulated by Tyr416 phosphorylation and negatively regulated by Tyr527 phosphorylation. Furthermore, neutrophil stimulation resulted in association of Src with the endothelial junction protein [beta]-catenin and [beta]-catenin tyrosine phosphorylation. These phenomena were abolished by blockage of Src activity. Taken together, our studies link for the first time neutrophil-induced hyperpermeability to a pathway involving Src kinase activation, Src/[beta]-catenin association, and [beta]-catenin tyrosine phosphorylation in the microvascular endothelium. permeability; transfection; phosphorylation; endothelium; microvessels

The 1994 Northridge, Calif., earthquake caused widespread permanent ground deformation on the gently sloping alluvial fan surface of the San Fernando Valley. The ground cracks and distributed deformation damaged both pipelines and surface structures. To evaluate the mechanism of soil failure, detailed subsurface investigations were conducted at four sites. Three sites are underlain by saturated sandy silts with low standard penetration test and cone penetration test values. These soils are similar to those that liquefied during the 1971 San Fernando earthquake, and are shown by widely used empirical relationships to be susceptible to liquefaction. The remaining site is underlain by saturated clay whose undrained shear strength is approximately half the value of the earthquake-induced shear stress at this location. This study demonstrates that the heterogeneous nature of alluvial fan sediments in combination with variations in the ground-water table can be responsible for complex patterns of permanent ground deformation. It may also help to explain some of the spatial variability of strong ground motion observed during the 1994 earthquake.

The details of the upstream signaling pathways from nitric oxide production in vascular endothelial growth factor (VEGF) induced venular hyperpermeability were studied in pigs. The apparent permeability coefficient of albumin and endothelial cystosolic calcium were measured in intact perfused porcine coronary venules using fluorescence microscopy. Results suggest that VEGF induces venular hyperpermeability through KDR receptor-mediated activation of phospholipase C.

A study was conducted to develop a way of transfecting endothelial cells supporting proteins for functional analysis. Bovine coronary venular endothelial cells were determined from postcapillary venules while cells were lysed in a cell lysis buffer. Experimental results indicated that the microvascular endothelium associated with various chemical stimuli and physical stress through an alteration of its role and structure.

Inflammatory lung diseases result in high rates of morbidity and mortality. Central to the pathogenesis of these diseases is disruption of endothelial barrier function, Activation of myosin light chain kinase (MLCK) is a key regulatory step in the modulation of endothelial permeability, Recent studies show that mice with a selective knockout of the endothelial MLCK are less susceptible to endotoxin-induced acute lung injury and that a new small-molecule inhibitor of MLCK also protects against lung injury.