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Biomedical subjects

E J Goetzl

Publications and source records attributed to E J Goetzl.

At least 235 records · Page 13Linked to original sources

Inhibition of complement-mediated functions of human neutrophils by impermeant stilbene disulfonic acids.

The impermeant labeling reagents 4,4'-diisothiocyanostilbene-2-2'-disulfonic acid (DIDS) and 4-acetamido-4'-isothiocyano-2,2'-disulfonic acid (SITS) inhibited in a concentration-related manner the enhanced generation of superoxide radicals (O2) by human neutrophils engaged in the phagocytosis of zymosan that had been opsonized in fresh serum, without altering the O2 generation by neutrophils exposed to zymosan opsonized in heat-decomplemented serum or to phorbol myristate acetate (PMA). That the stimulus specificity of the suppression of O2 generation by SITS and DIDS is predominantly attributable to an action on neutrophil plasma membrane receptors for complement was suggested by the similarity of the concentration dependence of the inhibition of the expression of neutrophil C3b receptors, as assessed by a rosetting assay. Washing neutrophils that had been pretreated with the covalent label DIDS failed to reverse either the suppression of C3b-dependent rosetting or the inhibition of O2 generation stimulated by opsonized zymosan. In contrast, pretreatment with DIDS and washing or erythrocytes bearing C3b and of opsonized zymosan did not inhibit their capacity to form rosettes and to stimulate O2 generation by neutrophils, respectively. In the same rosetting assay, the expression of IgG-Fc receptors was unaffected by SITS and DIDS. The rapid and apparently selective inhibition of the expression of neutrophil C3b receptors by noncytotoxic concentrations of the impermeant stilbene disulfonic acids may provide a means to analyze the complement dependence of other neutrophil effector functions.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

Vitamin E modulates the lipoxygenation of arachidonic acid in leukocytes.

The arachidonic acid released from cellular phospholipids of specifically stimulated platelets and leukocytes is oxygenated enzymatically by two major pathways. A complex cycloxygenase converts some of the free arachidonic acid to labile endoperoxides that are transformed to prostaglandins, thromboxanes and prostacyclin (PGI2). Lipoxygenases convert part of the arachidonic acid to unstable hydroperoxy-eicosatetraenoic acids (OOHETEs) that are transformed to monohydroxyeicosatetraenoic acids (HETEs), oligohydroxy-eicosatetraenoic or -eicostatrienoic acids such as di-HETEs and tri-HETEs, and, in some instances, more complex humoral mediators, including slow-reacting substances. Both the nature of the HETEs and the ratio of the HETEs to the cyclo-oxygenase products are specific characteristics of each type of cell. In human neutrophils, the sum of the lipoxygenase products 5-HETE, 11-HETE and 5,12-di-HETE substantially exceeds the total amount of PGE2 and other cyclo-oxygenase metabolites that are generated concurrently, and the endogenous lipoxygenase products regulate neutrophil function. The present data indicate that vitamin E (alpha-tocopherol) bidirectionally modulates the activity of the lipoxygenase pathway of human neutrophils in vitro. Normal plasma concentrations of alpha-tocopherol enhance the lipoxygenation of arachidonic acid, whereas higher concentrations of alpha-tocopherol exert a suppressive effect that is consistent with its role as a hydroperoxide scavenger.

Arachidonic Acids↗

The development of a radioimmunoassay for 12-L-hydroxyeicosatetraenoic acid.

Antibodies directed toward 12-L-hydroxyeicosatetraenoic acid (12-L-HETE) were generated in rabbits by immunization with conjugates of 12-L-HETE and human serum albumin. The concentration of antibodies was determined by incubating immune plasma with 12-L-HETE that had been covalently linked to a solid support, washing the 12-L-HETE support, and measuring the quantity of bound antibodies by reaction with [125I]Protein A. The addition of 0.5 ng-10 ng of fluid-phase 12-L-HETE to the standard mixture of solid-phase 12-L-HETE and anti-12-L-HETE plasma inhibited by 21-80% the binding of antibodies and consequently of [125I]Protein A to the solid support. The 12-OH function positioned between two double bonds was the immunodominant determinant of this antigen-antibody reaction, but the carboxyl function also was recognized. This radioimmunoassay was used to detect and quantitate 12-L-HETE resolved by high pressure liquid chromatography.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

Unique aspects of the modulation of human neutrophil function by 12-L-hydroperoxy-5,8,10,14-eicosatetraenoic acid.

12-L-hydroperoxy-5,8,10,14-eicosatetraenoic acid (12-OOHETE), a labile intermediate generated by the lipoxygenation of arachidonic acid in platelets, and 12-L-hydroxy-5,8,10.14-eicosatetraenoic acid (12-OHETE), the reduction product of 12-OOHETE, were examined for their effects on human neutrophil function in vitro. 12-OOHETE elicited a maximal neutrophil chemotactic response at 4 microgram/ml, that exceeded by over 50% the maximal chemotactic response to 10-20 microgram/ml of 12-OHETE. Similarly 12-OOHETE was more potent than 12-OHETE in evoking neutrophil chemokinetic responses and in enhancing the expression of C3b receptors on neutrophils. The concentration of guanosine 3':5' cyclic monophosphate (cGMP) in neutrophils was increased to the same plateau level by 5 ng/ml of 12-OOHETE and by 50 ng/ml of 12-OHETE. Elevations in the concentration of cGMP were maintained for 30 min or longer by a single dose of 12-OOHETE, but fell between 10 and 20 min after the introduction of 12-OHETE. The release of neutrophil lysosomal enzymes by the chemotactic fragments of C5 was augmented substantially by 12-OOHETE, while 12-OHETE had only a marginal effect. The non-chemotactic methyl ester of 12-OHETE failed to inhibit the chemotactic responses to 12-OOHETE at molar ratios that suppressed comparable response to 12-OHETE by 42-86%. Thus 12-OOHETE is more potent than 12-OHETE in the stimulation of some human neutrophil functions and in the elevation of the cellular concentration of cGMP. Furthermore, 12-OOHETE may activate neutrophils by pathways not available to 12-OHETE.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

Identification of human eosinophil lysophospholipase as the constituent of Charcot-Leyden crystals.

Since the initial descriptions of Charcot-Leyden crystals more than 100 years ago, the presence of these slender, dipyramidal crystals in human tissues and biologic fluids has become a hallmark of eosinophilic leukocyte infiltration, especially in association with allergic and helminthic diseases. The formation of these crystals in vitro after disruption of human eosinophils, but not of other cell types, in hypotonic saline or detergent established the eosinophil as the unique cellular source of the crystalline protein. Charcot-Leyden crystals have now been found to express lysophospholipase activity (lysolecithin acylhydrolase, EC 3.1.1.5), and the solubilized Charcot-Leyden crystal protein presents a single stained protein band that is coincident with the lysophospholipase activity eluted from replicate gels on alkaline polyacrylamide gel electrophoresis. On sodium dodecyl sulfate/polyacrylamide gel electrophoresis, the solubilized Charcot-Leyden crystal protein migrates with a molecular weight of 17,400, which is comparable to that of eosinophil lysophospholipase purified chromatographically to homogeneity; further, on combination, the two proteins comigrate as a single staining band. Finally, the chromatographically purified eosinophil lysophospholipase in hypotonic buffer forms dipyramidal crystals morphologically identical to Charcot-Leyden crystals. The findings that chromatographically purified, homogeneous eosinophil lysophospholipase and Charcot-Leyden crystal protein express the same enzymatic activity, are of the same size and charge, and form crystals of identical morphology indicate that human eosinophil lysophospholipase is the constituent of Charcot-Leyden crystals.

Crystallography↗

Constituents of human neutrophils that mediate enhanced adherence to surfaces: purification and identification as acidic proteins of the specific granules.

The endogenous constituents of human neutrophils that enhance the adherence of the neutrophils to surfaces have been isolated from sonicates of purified neutrophils. The predominant adherence-enhancing activity in the neutrophil sonicates cofiltered on Sephadex G-75 with a major peak of chemotactic inhibitory activity and exhibited approximately 30,000 mol wt. Sequential isoelectric focusing and electrophoresis in glycerol gradients of the 30,000-mol wt activities resolved two distinct acidic protein with isoelectric points of 3.6-3.8 and 3.3-3.4 that were designated the neutrophil adherence factor (NAF) I and II, respectively. Glutamic acid and aspartic acid together accounted for a total of 18 and 19% of the amino acids in purified preparations of NAF I and NAF II, respectively, whereas the basic amino acids lysine, arginine, and histidine represented <2 and 3% of the total residues. The preincubation of portions of 2 x 10(6) neutrophils with as little as 6 pmol of NAF I or 9 pmol of NAF II enhanced adherence to plastic petri dishes and inhibited chemotactic migration to a maximal extent, with comparable dose-response relationships for the two effects. Neither of the NAF was cytotoxic, exhibited substantial neutrophil chemotactic or chemokinetic activity, or influenced the phagocytosis of sheep erythrocytes sensitized with immunoglobulin (Ig)G. Analyses of subcellular fractions of neutrophils indicated that the NAF are contained predominantly in the specific granules. These distinctive acidic proteins of the specific granules of human neutrophils represent a new class of endogenous constituents that may regulate the involvement of neutrophils in inflammation.

Amino Acids↗

Lipoxygenation of arachidonic acid as a source of polymorphonuclear leukocyte chemotactic factors in synovial fluid and tissue in rheumatoid arthritis and spondyloarthritis.

The predominant lipoxygenase products of arachidonic acid were extracted and purified from synovial fluid and sonicates of synovial tissue of patients with rheumatoid arthritis (RA), spondyloarthritis (SA), or a noninflammatory arthropathy (NIA). The concentration of 5(S),12(R)-dihydroxy-6,8,10-(trans/trans/cis)-14-cis-eicosatetraenoic acid (leukotriene B4) in synovial fluid was elevated significantly in patients with RA and a positive latex test for rheumatoid factor (P < 0.05, n = 14) and in patients with SA (P < 0.05, n = 10), compared with that of subjects with NIA (n = 9). The content of 5(S)-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), but not of leukotriene B4, was elevated significantly in synovial tissue of seven patients with RA in comparison with that of four subjects with NIA (P < 0.05). A single intra-articular injection of corticosteroid significantly lowered the synovial fluid level of leukotriene B4 in six patients with RA. These data suggest an involvement of the potent chemotactic factors 5-HETE and leukotriene B4 in human inflammatory disease.

Arachidonic Acids↗

Modulation of human neutrophil function by monohydroxy-eicosatetraenoic acids.

The generation from arachidonic acid and purification of large quantities of a series of monohydroxy-eicosatetraenoic acids (HETEs) which differed only in the position of the hydroxyl group permitted an in vitro analysis of the relative effects of the HETEs on a variety of human neutrophil functions. All of the HETEs elicited maximal neutrophil chemotactic responses of comparable magnitude, but the chemotactic potencies exhibited a distinct rank order with 5-HETE greater than 8-HETE:9-HETE (85:15, w:w) greater than 11-HETE=12-L-HETE. Peak chemotactic responses were achieved at concentrations of 1 microgram/ml for 5-HETE, 5 microgram/ml for 8-HETE:9-HETE and 10 microgram/ml for 11-HETE and 12-L-HETE. In the absence of a concentration gradient, the HETEs were similar in potency with respect to the stimulation of neutrophil chemokinesis and the enhancement of the expression of neutrophil C3b receptors. At optimally chemotactic and chemokinetic concentrations, none of the HETEs stimulated the generation of superoxide by neutrophils, altered the expression of neutrophil IgG-Fc receptors, or evoked the release of lysosomal enzymes. Methyl esterification of 5-HETE and 12-L-HETE reduced the chemotactic activity to less than 12% of that of the parent compound. The HETE methyl esters competitively inhibited the chemotactic activity of the homologous free acids by approximately 50% at equimolar concentrations, without inhibiting the chemotactic activity of formyl-methionyl peptides or of chemotactic fragments of the fifth component of complement (C5fr). The stimulus specificity of the competitive inhibition of chemotaxis by HETE methyl esters and the functional selectivity of the HETEs as compared to the formyl-methionyl peptides and C5fr, which stimulate neutrophil oxidative metabolism and lysosomal enzyme release, suggest that HETEs activate human neutrophils by a unique mechanism.

Arachidonic Acids↗

A role for endogenous mono-hydroxy-eicosatetraenoic acids (HETEs) in the regulation of human neutrophil migration.

The possibility that endogenous monohydroxy-eicosatetraenoic acids (HETEs) derived from the lipoxygenation of arachidonic acid might serve a role in human neutrophil migration was examined by studying the effects of depletion of the intracellular HETEs on random migration and chemotaxis. The intracellular contents of approximately 2000 ng of 11-HETE and 500 ng of 5-HETE per 10(8) neutrophils are distributed preferentially in the cellular membranes and are increased by specific chemotactic factors. The depletion of intracellular HETEs that resulted from pre-incubating, washing and resuspending neutrophils in 3-20 microM 5,8,11,14-eicosatetraynoic acid (TYA), an inhibitor of lipoxygenase and cyclooxygenase activity, or in 5-10 microM nordihydroguaiaretic acid (NDGA), a selective inhibitor of lipoxygenase activity, was associated with suppression of neutrophil random migration and chemotaxis to several stimuli without evidence of cytotoxicity. Maximal suppression of migration was achieved by a 30-60 min preincubation with the inhibitors, a time-course analogous to that required for optimal depletion of the endogenous HETEs. In contrast, inhibitors of cyclooxygenase activity enhanced random migration and, to a lesser extent, chemotaxis. The inhibition of migration achieved by pre-incubating and maintaining the neutrophils in TYA or NDGA was fully reversed either by washing and resuspending the neutrophils in buffer or by the addition of purified neutrophil 5-HETE in quantities as small as 20 ng/2 x 10(6) neutrophils for random migration and 0.8 ng/2 x 10(6) neutrophils for chemotaxis, while the addition of 11-HETE was less effective. The relationship of the intracellular concentrations of endogenous HETEs to neutrophil migration is consistent with a potential role of the HETEs as cellular mediators.

5,8,11,14-Eicosatetraynoic Acid↗

Structural requirements for the activity of an immunologically generated lipid chemotactic factor.

The predominant lipid chemotactic factor (LCFR) generated by IgGa-dependent immunological challenge of the rat peritoneal cavity was resolved from other lipid mediators released simultaneously into the peritoneal cavity and from previously described lipid chemotactic factors by sequential chromatography on Amberlite XAD-8, DE-52, silicic acid, and silica gel H plates, and by Zorbax C-18 reverse phase high pressure liquid chromatography. The incubation of purified rat peritoneal mononuclear leucocytes, but not mast cells, with calcium ionophore A23187 in vitro resulted in the generation of LCFR activity which was chromatographically identical to the LCFR released in vivo. That indomethacin inhibited the appearance of LCFR both in vivo and in vitro indicated a dependence on the cyclo-oxygenation of arachidonic acid. Because of the limited quantities of highly purified LCFR, the critical determinants of human neutrophil chemotactic activity were studied by examining the functional effects of chemical modification of specific substituents. The chemotactic activity of LCFR was diminished significantly by acetylation with acetic anhydride in pyridine or methylation with ethereal diazomethane, but was not influenced by 0.1 M periodate or acid or base hydrolysis, suggesting that LCFR is a complex fatty acid containing a hydroxyl or amino group. The addition of acetylated LCFR to the stimulus compartment at a 0.3-0.5 molar ratio with native LCFR diminished the neutrophil chemotactic response by 50%, without affecting a comparable response to f-Met-Leu-Ala-Phe. Thus LCFR is a unique lipid chemotactic factor which is distinct from other lipid mediators and accounts for the bulk of the PMN leucocyte chemotactic activity released by immunological challenge of the rat peritoneal cavity.

Animals↗