Quantitative expression and localization of cysteine and aspartic proteases in human abdominal aortic aneurysms

Cysteine and aspartic proteases possess high elastolytic activity and might contribute to the degradation of the abdominal aortic aneurysm (AAA) wall. The aim of this study was to analyze, in detail, the proteases (cathepsins B, D, K, L and S, and inhibitor cystatin C) found in human AAA and healthy aortic tissue samples. The vessel walls from AAA patients (n=36) and nonaneurysmal aortae (n=10) were retrieved using conventional surgical repair and autopsy methods. Serum samples from the same AAA patients and 10 healthy volunteers were also collected. Quantitative expression analyses were performed at the mRNA level using real-time reverse transcriptase-PCR (RT-PCR). Furthermore, analyses at the protein level included western blot and immunoprecipitation analyses. Cellular sources of cysteine/aspartic proteases and cystatin C were identified by immunohistochemistry (IHC). All cysteine/aspartic proteases and cystatin C were detected in the AAA and control samples. Using quantitative RT-PCR, a significant increase in expression was observed for cathepsins B (P=0.021) and L (P=0.018), compared with the controls. Cathepsin B and cystatin C were also detected in the serum of AAA patients. Using IHC, smooth muscle cells (SMCs) and macrophages were positive for all of the tested cathepsins, as well as cystatin C; in addition, the lymphocytes were mainly positive for cathepsin B, followed by cathepsins D and S. All cysteine/aspartic proteases analyzed in our study were detected in the AAA and healthy aorta. The highest expression was found in macrophages and SMCs. Consequently, cysteine/aspartic proteases might play a substantial role in AAA.

Simvastatin acts as an inhibitor of interferon gamma-induced cycloxygenase-2 expression in human THP-1 cells, but not in murine RAW264.7 cell

Cyclooxygenase-2 (COX-2) is a key inflammatory response molecule, and associated with many immune functions of monocytes/macrophages. Particularly, interferon gamma (IFNgamma)-induced COX-2 expression appears in inflammatory conditions such as viral infection and autoimmune diseases. Recently, statins have been reported to show variable effects on COX-2 expression, and on their cell and species type dependences. Based on the above description, we compared the effect of simvastatin on IFNgamma-induced COX-2 expression in human monocytes versus murine macrophages. In a result, we found that simvastatin suppresses IFNgamma-induced COX-2 expression in human THP-1 monocytes, but rather, potentiates IFNgamma-induced COX-2 expression in murine RAW264.7 macrophages. However, signal transducer and activator of transcriptio n 1/3 (STAT1/3), known as a transcription factor on COX-2 expression, is inactivated by simvastatin in both cells. Our findings showed that simvastatin is likely to suppress IFNgamma-induced COX-2 expression by inhibiting STAT1/3 activation in human THP-1 cells, but not in murine RAW264.7 cells. Thus, we concluded that IFNgamma-induced COX-2 expression is differently regulated by simvastatin depending on species specific mechanism.

Caracterización de los fagocitos mononucleares en la sangre de phrynops hilarii (Chelonia chelidae) / Characterization of blood mononuclear phagocytes in Phrynops hilarii (Chelonia chelidae)

The localization of peroxidase activity in different cell regions is used as a criterion for the classification of the stage of maturation of mammalian mononuclear phagocytes with a positive peroxidase reaction indicating the presence of monoblasts, promonocytes, monocytes and macrophages. In this study it was evaluated the peroxidase activity of blood mononuclear phagocytes of this turtle detected at different stages of differentiation. The present observations suggest that, in turtles, the differentiation of mononuclear phagocytes occur in the blood circulation, in contrast to animals, where only are monocytes in circulating blood and macrophage differentiation occurs in other body compartments.

La localization de la actividad de la peroxidasa en diversas regiones de la célula se utiliza como criterio para la clasificación de la etapa de maduración de fagocitos mononucleares. Una reacción positiva de peroxidasa indica la presencia de monoblastos, promonocitos, monocitos y macrófagos. En este estudio fue evaluada la actividad de la peroxidasa de los fagocitos mononucleares de la sangre de la tortuga Phrynops Hilarii detectada en diversas etapas de la diferenciación. Las actuales observaciones sugieren que, en tortugas, la diferenciación de fagocitos mononucleares ocurre en la circulación de la sangre, en contraste a los mamíferos, donde están solamente los monocitos en la sangre circulante y la diferenciación de los macrófagos ocurre en otras partes del cuerpo.

Preliminary study on the production of nitric oxide and expression of nitric oxide synthase by camel macrophages [with one table and one figure]

Nitric Oxide is produced by macrophage when activated or invaded by certain antigens or microbes. In the present study, camel peripheral blood leukocytes were obtained by ficoll cushion. Monocytes were separated and grown to macrophages. The mature macrophages were exposed to E. coli LPS as well as sheep pox virus antigen. Nitric oxide [NO] production, by stimulated macrophages as well as the mRNA specific for production of inducible nitric oxide syntheses [iNOS], were investigated. Production of NO was stimulated by both pox antigen and LPS and was more with the latter. The obtained results indicated the similarity in the tested parameters between camel macrophages and those of other mammals tested so far viz mice

Induction of nitric oxid esynthase(NOS) by soluble glucocorticoid induced tumor necrosis factor receptor(sGITR) is modulated by IFN-g in murine macrophage

Earlier study showed that glucocorticoid induced tumor necrosis factor receptor (GITR), a new TNFR family, activated murine macrophages to express inducible nitric oxide synthase (iNOS) and to generate nitric oxide (NO). A possible involvement of pro-inflammatory cytokines on NO production by GITR was investigated in vitro systems and signaling molecules contributing to sGITR-induced iNOS production are determined in Raw 264.7 cells, a murine macrophage cell line. The result showed that the synergy was afforded by the combination of GITR with IFN-gamma in a dose-dependent manner but IFN-gamma alone was not able to induce NOS. No effects were observed with TNF-alpha, IL-1beta, or IL-6 co-treated with GITR. To determine signaling molecules contributing to sGITR-induced iNOS production, a specific inhibitor for signal pathway proteins tested showed that PDTC (NF- kB) and genistein (tyrosine kinase) inhibited NOS induction significantly, while sodium orthovanadate (tyrosine phosphatase) potentiated NOS expression. These results suggest that activations of NF-kB were involved in induction of iNOS by GITR and IFN-gamma priming caused earlier and stronger NF-kB activation.

Leishmanial antigens in the diagnosis of active lesions and ancient scars of American tegumentary leishmaniasis patients

Cutaneous biopsies (n = 94) obtained from 88 patients with American tegumentary leishmaniasis were studied by conventional and immunohistochemical techniques...

Increased expression of neuronal nitric oxide synthase in astrocytes and macrophages in the spinal cord of Lewis rats with autoimmune encephalomyelitis

Neuronal nitric oxide synthase (nNOS) is constitutively expressed in neurons of the central nervous system, where it plays a physiological role in neurotransmission. In this study, we examined the functional role of nNOS in experimental autoimmune encephalomyelitis(EAE). The effects of the specific nNOS inhibitor 7-nitroindazole on normal and EAE rats were studied by immunohistochemistry and Western blot analysis. We found that nNOS is constitutively expressed in the spinal cords of normal rats, whilst in the spinal cords of EAE rats, nNOS expression slightly increased, concomitant with the infiltration of T cells and macrophages. Immunohistochemical studies showed that nNOS expression in macrophages and astrocytes increased at the peak stage of EAE and declined thereafter. Treatment with 7-nitroindazole (30 mg/kg) significantly delayed the onset of EAE paralysis, but had no effect on either the incidence or the severity of the paralysis. These findings suggest that nNOs inhibition has a limited role in the induction of rat EAE, and that constitutive nNOS in the spinal cord functions as a novel neurotransmitter, rather than a pro-inflammatory agent.

The effects of oxygen radicals on the activity of nitric oxide synthase and guanylate cyclase

Reactive oxygen species such as superoxides, hydrogen peroxide (H2O2) and hydroxyl radicals have been suggested to be involved in the catalytic action of nitric oxide synthase (NOS) to produce NO from L-arginine. An examination was conducted on the effects of oxygen radical scavengers and oxygen radical-generating systems on the activity of neuronal NOS and guanylate cyclase (GC) in rat brains and NOS from the activated murine macrophage cell line J774. Catalase and superoxide dismutase (SOD) showed no significant effects on NOS or GC activity. Nitroblue tetrazolium (NBT, known as a superoxide radical scavenger) and peroxidase (POD) inhibited NOS, but their inhibitory actions were removed by increasing the concentration of arginine or NADPH respectively, in the reaction mixture. NOS and NO-dependent GC were inactivated by ascorbate/FeSO4 (a metal-catalyzed oxidation system), 2'2'-azobis-amidinopropane (a peroxy radical producer), and xanthine/xanthine oxidase (a superoxide generating system). The effects of oxygen radicals or antioxidants on the two isoforms of NOS were almost similar. However, H2O2 activated GC in a dose-dependent manner from 100 microM to 1 mM without significant effects on NOS. H2O2-induced GC activation was blocked by catalase. These results suggested that oxygen radicals inhibited NOS and GC, but H2O2 could activate GC directly.

Fosfatasa acida leucocitaria tartrato resistentecomo marcador de la transformacion del monocito en macrofago / Leucocyte tartrate-resistant acid phosphatase as marker for the transition of monocyte to macrophage

Se investigó la presencia de la 5 isoenzima de la fosfatasa ácida leucocitaria tartrato resistente (FATRE) en los monocitos de sangre periférica humana en 32 muestras: 26 normales, 4 plaquetopenias, 1 anemia y 1 tricoleucemia. Se empleó el separador celular Cobe Spectra Versión 4 en 3 muestras y en las demás se obtuvo la concentración celular por centrifugación sin y con partículas de látex, para estudiar monocitos y macrófagos, respectivamente. Empleando el Kit Sigma para las dos reacciones de fosfatasa ácida total y de FATRE, se demostró la presencia de dos poblaciones de monocitos, una minoritaria para FATRE y otra negativa. Con la adición de látex los monocitos se transformaron en macrófagos haciéndose fuertemente positivos para FATRE. En consecuencia se concluye que la FATRE debe desempeñar un papel principal en la función macrofágica y por ende en la inmunidad celular humana.

Antioxidant enzyme activities in the lymphoid organs and macrophages of rats trained to perform moderate exercise

Strenous exercise and high levels of athletic competition may suppress immune function, increasing susceptibility to infections. Infections are often associated with a reduction in athletic performance and can have permanent or lethal consequences. Recent research, however; suggests that regular paraticipation in moderate exercise has an immunoenhancing effect but the mechanism involved remains unknown. This study examined the effect of moderate exercise (70 per cent of maximal oxygen consumption - swimming for 1 hour daily at 32 degrees Celsius with 5 per cent body weight extra load attached to the tail) training on antioxidant enzyme activities and lipid peroxidation in the lymphoid organs (mesenteric lymph nodes, thymus and spleen) and macrophages of rats. This modality of physical effort reduced the content of lipide peroxides in the lymphoid organs. The authors assumed that this effect of exercise training resulted in increased activity of antioxidant enzymes: Glutathione peroxidase in the mesenteric lymph nodes (2.1 fold) and spleen (3-fold), catalase in the spleen (5-fold) and Mn-superoxide dismutase (SOD) in the thymus (28 per cent). The exercise training increased the hydrogen peroxide production and phagocytic capacity in macrophages which was accompanied by a higher Mn-SOD activity. Therefore, a moderate exercise may be the able to improve immune function due to changes in the oxidative metabolism of the lymphoid organs and macrophages.

The ecto-ATPases of endoparasites and of blood cells and vessels

The cells of blood vessel walls and the external surface of all blood cells have an ecto-ATPase which hydrolyzes ATP to ADP and also ADP to AMP. This enzyme has also been called apyrase or ATP-diphosphohydrolase. The enzyme hydrolyzes a broad range of tri-and diphosphate nucleosides such as UTP and UDP, GTP and GDP in additon to the adenine nucleotides and because of that it has also been called a nucleoside triphosphate hydrolase. The possible physiological roles for this ecto-ATPase involve the control of vascular tone by modulation of the levels of ATP and ADP binding to purino-receptors of the vasculature, the modulation of thrombogenesis by controlling the extracellular level of ADP which is known to activate platelet aggregation, and the protection from cytolytic effects of extracellular ATP. An ATP-diphosphohydrolase activity has been characterized on the external surface of Schistosoma mansoni, a parasite that lives in the circulation of the human host, and on the outer surface of Entamoeba histolytica, a parasite that may enter the circulation of the host through ulceration in the intestinal mucosa. The endoparasite Toxoplasma gondii also exhibits a nucleoside triphosphate hydrolase of high activity, although in this case the ecto-localization is still not documented. We raise the possibility that the endoparasites have evolved in a way to possibly mimic some of the conditions on the surface of cells normally present in the host circulation, thus escaping hemostatic defense responses of the host which require extracellular ADP or ATP.

Hydrolytic activity of an onchocercoma

The onchocercoma or nodule produced by the nematode Onchocerca volvulus (Filarioidea) in the skin of patients suffering from onchocerciasis has not been examined by histochemical techniques. In this work we have used histochemical techniques to evaluate 5 hydrolytic enzymes, namely phosphatases, esterases and beta-glucuronidase. The results show increased enzymatic activity at the sites of major metabolic activity and within reactive cells including macrophages (mc) and giant cells (gc) of the onchocercoma

Activation of lysosomal enzymes in chemotactically elicited rat peritoneal macrophages.

Activation profile of lysosomal enzymes in rat peritoneal macrophages elicited in response to three stimulants, thioglycollate (TG), protease peptone (PP) and lipopolysaccharide (LPS) was studied from 0 to 6 days. Macrophages elicited in response to LPS were larger in number and heterogeneous in nature while TG and PP induced cells were comparatively more homogeneous. Maximum elicitation of macrophages in response to the three stimulants, though at different degrees, was observed around 3 days. This could be correlated to increased blood monocytes. The progressive activation of macrophages reflected in corresponding decrease in total cellular protein content and increase in the activities of their lysosomal enzymes. The catalytic activities of aryl sulphatase, beta-glucuronidase and cathepsin D increased several fold (2-8 fold) over the resident values. TG elicited cells possessed the highest enzyme activities, followed by PP and LPS elicited ones. Beta-Glucuronidase was the most stimulated (4-8 fold) of the enzymes studied. The cellular catalytic activities of these enzymes were also enhanced 2- to 4-fold compared to the resident levels in the TG and PP elicited macrophages. Though the enzyme catalytic activities were increased in the LPS treated cells, their cellular levels remained below the resident activities in all the three enzymes studied. The results indicate that the events related to the elaboration of these macrophage lysosomal enzymes in vivo are subject to selective modulation and are stimulus specific.

Hydrolytic enzymes in macrophages from leprosy patients in presence of Mycobacterium leprae.

Presence of Mycobacterium leprae in association with in vitro cultured macrophages, from bacillary negative long term treated lepromatous leprosy patients, induces reduced level of protein and lowering of hydrolytic enzymes like p-glucuronidase, Lysozyme and Lactic dehydrogenase. Alkaline phosphatase, on the other hand is increased. In the macrophages from normal healthy individuals or tuberculoid leprosy patients, presence of M.leprae increases both protein and levels of all the above enzymes. This observation shows that macrophages from lepromatous leprosy patients are unable to manifest in presence of M. leprae, the key enzymes involved in degradation of complex biological entities phagocytosed by the cells.