Superoxide dismutase (SOD) as a potential inhibitory mediator of inflammation via neutrophil apoptosis

Superoxide dismutase (SOD) is supposed to be an effective agent for neutrophil-mediated inflammation in the area of critical medicine. We investigated the involvement of SOD in the regulation of neutrophil apoptosis. Exogenously added SOD effectively induced neutrophil apoptosis, and the fluorescence patterns determined using annexin-V and the 7-AAD were similar to those seen in Fas-mediated neutrophil apoptosis. Neutrophils are short-lived leukocytes that need to be removed safely by apoptosis. The clearance of apoptotic neutrophils from sites of inflammation is a crucial determinant of the resolution of inflammation. Catalase inhibited the neutrophil apoptosis and caspase-3 activation. Spontaneous apoptosis, hydrogen peroxide and anti-Fas antibody-induced apoptosis of neutrophils were accelerated in Down's syndrome patients, in whom the SOD gene is overexpressed. Hydrogen peroxide was thought to be a possible major mediator of ROS-induced neutrophil apoptosis in caspase-dependent manner. Neutrophil apoptosis represents a crucial step in the mechanism governing the resolution of inflammation and has been suggested as a possible target for the control of neutrophil-mediated tissue injury. SOD may be a potential inhibitory mediator of neutrophil-mediated inflammation.     

Histochemical staining and quantification of plant mitochondrial respiratory chain complexes using blue-native polyacrylamide gel electrophoresis

Our knowledge of the respiratory chain and associated defects depends on the study of the multisubunit protein complexes in the inner mitochondrial membrane. Functional analysis of the plant mitochondrial respiratory chain has been successfully achieved by a combination of blue-native polyacrylamide gel electrophoresis (BN-PAGE) for separation of the protein complexes, and in-gel histochemical staining of the enzyme activities. We have optimized this powerful technique by determining linear ranges of amount of protein and enzyme activity for each respiratory complex. Time courses of the in-gel enzyme activities were also performed to determine optimal reaction times. Using the in-gel activity staining method we have previously shown decreased activity of complex V (F(1)F(0)-ATPase) in male-sterile sunflowers (Sabar et al., 2003). Here we have identified unique supercomplexes comprising complex IV (cytochrome c oxidase) in sunflower mitochondria. This method therefore represents a reliable tool for the diagnosis of respiratory dysfunction. In addition, the wider application of BN-PAGE in combination with enzyme activity staining is discussed.     

Autoantibodies against oxidized LDL are associated with severe chest pain attacks in patients with coronary heart disease

Autoantibodies against oxidized low-density lipoprotein (oxLDL) predict the progression of atherosclerosis. Several studies have shown that oxLDL is present in atherosclerotic lesions and that several factors present in active atherosclerotic plaques can oxidatively modify LDL. Oxidation of LDL induces production of autoantibodies against oxLDL (oxLDLab) that can be measured using an EIA test. Our aim was to see whether oxLDLab are associated with severe chest pain attacks in coronary heart disease (CHD) patients. Patients having two- or three-vessel CHD, as assessed by coronary angiography, and their siblings were recruited into the study (n = 568, mean age 55.8 years, range 29.3–83.2 years). Nondiabetic patients having a history of severe chest pain attacks had significantly higher oxLDLab levels (0.611 ± 0.56) than those who did not have a history of severe chest pain attacks (0.487 ± 0.40) (p = 0.027), even though age, cholesterol level, body mass index, and blood pressure were similar in both groups. However, no difference was found in oxLDLab levels in diabetic patients with or without a history of severe chest pain attacks. Increased levels of oxLDL autoantibodies are associated with severe chest pain attacks in nondiabetic patients with CHD.     

Orientation and Dispersal Patterns of the Eastern Tent Caterpillar, <Emphasis Type="Italic">Malacosoma americanum</Emphasis> F. (<Emphasis Type="Italic">Lepidoptera: Lasiocampidae</Emphasis>)

Larvae of the eastern tent caterpillar, Malacosoma americanum, undergo density-dependent dispersal in response to depleted resources. Because these caterpillars have recently been implicated in abortions of pregnant mares (equine Mare Reproductive Loss Syndrome, or MRLS), there is increased interest in managing caterpillar populations, potentially through manipulation of caterpillar dispersal behavior. Consequently, we investigated dispersal patterns of food-deprived eastern tent caterpillars in artificial arenas with respect to distance, direction, and response to visual stimuli. Distance traveled is influenced by time of day, and is strongly correlated with time elapsed. Movement is non-random, and correlates closely with the position of the sun. The pattern is more pronounced with foraging third instars than with penultimate fifth instars. Visual cues appear important in caterpillar orientation, and caterpillars are responsive to vertically oriented, black objects.     

Transgenic expression of <Emphasis Type="Italic">CECR1</Emphasis> adenosine deaminase in mice results in abnormal development of heart and kidney

Cat eye syndrome is a rare developmental defect associated with duplication of chromosome 22q11. The patients demonstrate specific abnormalities of heart, kidney, and eye. Here we attempted to produce a model for this defect by expressing CECR1 adenosine deaminase, a gene duplicated in cat eye syndrome patients, in mice. The transgenic mice expressed CECR1 under the control of either β-actin promoter for ubiquitous expression or myosin heavy chain for heart-specific expression. The transgenics expressing CECR1 in the heart demonstrated high rate of embryonic and neonatal lethality. The mice from all the lines examined showed enlargement of the heart. Abnormalities of the kidney and eye were also detected in mice expressing CECR1 under control of the actin promoter.     

Ca2+ ionophores trigger membrane remodeling without a need for store-operated Ca2+ entry

Calcium (Ca2+) ionophores are the most effective agents able to elicit rapid membrane remodeling in vitro. This process exposes aminophospholipids at the surface of platelets and blood cells, thus providing a catalytic surface for coagulation. To explore the underlying mechanism, we examined if cytosolic Ca2+ ([Ca2+]i) increase through store-operated Ca2+ entry (SOCE) was necessary for the potent effect of ionophores. Recent studies have demonstrated that the Ca2+-ATPase inhibitor thapsigargin, although able to elevate [Ca2+]i through SOCE, does not trigger the rapid membrane remodeling. However, it was not known if the additional effect of ionophores to promote the process required SOCE or could it occur independently. We took advantage of two mutant B lymphoblast cell lines, characterized either by defective SOCE or altered membrane remodeling, to simultaneously assess [Ca2+]i increase and membrane remodeling in the presence of ionophores or thapsigargin. Results imply that ionophores trigger membrane remodeling without the requirement for a functional SOCE.     

A comparison of the behavior of cholesterol and selected derivatives in mixed sterol-phospholipid Langmuir monolayers: a fluorescence microscopy study

Eukaryotic cells require sterols to achieve normal structure and function of their plasma membranes, and deviations from normal sterol composition can perturb these features and compromise cellular and organism viability. The Smith-Lemli-Opitz syndrome (SLOS) is a hereditary metabolic disease involving cholesterol (CHOL) deficiency and abnormal accumulation of the CHOL precursor, 7-dehydrocholesterol (7DHC). In this study, the interactions of CHOL and the related sterols desmosterol (DES) and 7DHC with l-alpha-dipalmitoylphosphatidylcholine (DPPC) monolayers were compared. Pressure-area isotherms and fluorescence microscopy were used to study DPPC monolayers containing 0, 10, 20, or 30 mol% sterol. Similar behavior was noted for CHOL- and DES-containing DPPC monolayers with both techniques. However, while 7DHC gave isotherms similar to those obtained with the other sterols, microscopy indicated limited domain formation with DPPC, indicating that 7DHC packs somewhat differently in DPPC membranes compared to CHOL and DES. These results are discussed in relation to SLOS pathobiology.     

Inactivation of tensin3 in mice results in growth retardation and postnatal lethality

Tensin family is a group of focal adhesion proteins that interact with integrins, actin, and phosphotyrosine-containing proteins. To explore the in vivo functions of a new member of the family, tensin3, we have generated mutant mice with a disrupted tensin3 gene. Inactivation of tensin3 resulted in growth retardation and postnatal lethality in one third of the homozygous mutants. Histological analysis of those mutants showed incomplete development of the small intestine, lung, and bone. Villus formation in the small intestine was affected and cells migrated slower in the runt mutants. Their lungs also displayed enlarged air space suggesting defects in alveogenesis. In addition, the resting zone was thicker and fewer proliferating cells were present in the growth plates of tensin3(-/-) tibiae. These observations indicate that tensin3 is essential for normal development and functions of the small intestine, lung, and bone. These phenotypes of the runt tensin3(-/-) mice are similar to some clinical features of Silver-Russell syndrome (SRS) which is a genetically inherited defect. About 10% of SRS cases have been linked to abnormality in chromosome 7p11.2-13, where human tensin3 gene is located, suggesting a potential link between tensin3 and SRS.