3-3--dipentyl-2-2--oxacarbocyanine and Granulomatous-Disease--Chronic

The chemotactic peptide formylmethionyl-leucyl-phenylalanine (fMLP), at concentrations below 10(-9) M, elicits a sustained increase in the human neutrophil's membrane potential within 10 s of its addition. This hyperpolarization, detected with the fluorescent cationic potentiometric probes, 3,3'-dipentyloxacarbocyanine (diO-C5-(3)), and 1,1'-dipropyl-3,3,3',3'-tetramethylindocarbocyanine iodide (diI-C3-(3)), and with the anionic probe bis-(1,3-diethylthiobarbituric)trimethine oxonol (bis-oxonol), is immediately followed by a large depolarization when [fMLP] greater than 10(-9) M. By extracellular substitution of sodium ions with potassium ions or choline or by pretreatment of the cells with ionophores, we report here that the hyperpolarization is primarily dependent on an intact potassium ion gradient and is accompanied by a concurrent acidification of the cytoplasm (approximately 0.05 pH unit) Although the latter occurs simultaneously with a large, transient increase in cytosolic Ca2+ at [fMLP] greater than 10(-10) M, it occurs without a detectable increase in cytosolic Ca2+ at [fMLP] less than 10(-10) M. The hyperpolarization is neither affected nor initiated by the chemotactic peptide antagonist tert-butyloxycarbonyl-methionyl-leucyl-phenylalanine, whereas the depolarization is completely inhibited. Neutrophils isolated from patients with X-linked chronic granulomatous disease exhibit normal hyperpolarizations and cytosolic Ca2+ increases in response to chemotactic peptides but exhibit no depolarization or oxidative burst. The hyperpolarization appears earlier in the ontogeny of differentiating myeloid precursor cells than either the rise in cytosolic Ca2+ or the depolarization response. Together, these findings indicate that an increase in transmembrane potential is one of the earliest events in the neutrophil response to chemotactic peptides, coinciding temporally with increases in cytoplasmic Ca2+ and H+ concentrations but preceding detectable oxidative burst activity.

Topics: Amino Acid Sequence; Calcium; Carbocyanines; Cell Membrane; Choline; Cytosol; Dose-Response Relationship, Drug; Fluorescent Dyes; Granulomatous Disease, Chronic; Humans; Hydrogen-Ion Concentration; Membrane Potentials; Molecular Sequence Data; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Oligopeptides; Potassium; Potassium Channels; Sodium; Sodium-Potassium-Exchanging ATPase; Thiobarbiturates

Previous studies using membrane potential sensitive probes have provided evidence that chemotactic factors elicit membrane potential changes in normal human neutrophils (PMN). In addition to stimulation of PMN motility, chemotactic factors also stimulate degranulation and superoxide ion (O-2) generation and it has been suggested that alteration of membrane potential activates these events (Korchak, H. M., and G. Weissmann. 1978. Proc, Natl, Acad, Sci. U. S. A. 75: 3818--3822). To further define the inter-relationship of these functions, studies were done with two indirect probes of membrane potential, 3-3'-dipentyloxacarbocyanine and triphenylmethylphosphonium ion (TPMP+) using PMN from normal subjects, from patients with abnormal O-2 production (chronic granulomatous disease [CGD]), and from patients with defective degranulation and/or chemotaxis (Cheddiak-Higashi syndrome and patients with elevated immunoglobulin (Ig)E and recurrent staphylococcal infections). The stimuli used were the chemoattractant N-formyl-methionyl-leucyl-phenylalanine (f-Met-Leu-Phe) and the secretagogues ionophore A23187 and phorbol myristate acetate (PMA). The results obtained with 3-3'-dipentyloxacarbocyanine and TPMP+ were comparable. The apparent membrane potential changes elicited by f-Met-Leu-Phe and PMA in normal PMN were reduced or entirely absent in PMN obtained from patients with CGD but normal in PMN from other patients. PMN from patients with CGD had normal calculated resting membrane potentials and normal responses elicited by the potassium ionophore valinomycin. The responses to calcium ionophore A23187 were only slightly impaired. The abnormality of the elicited response of CGD cells of f-Met-Leu-Phe and PMA could not be attributed to the absence of O-2, hydroxyl radical, singlet oxygen, or hydrogen peroxide acting on the probes. Instead this abnormality appears to be associated with a dysfunction in the normal molecular mechanism(s) stimulated upon neutrophil activation. The data suggest chemoattractant alteration of membrane potential in normal PMN is related to activation of oxidative metabolism but the relationship to chemotaxis and degranulation remains to be established.

Topics: Adolescent; Adult; Calcimycin; Carbocyanines; Chediak-Higashi Syndrome; Chemotactic Factors; Chemotaxis, Leukocyte; Child; Child, Preschool; Female; Granulomatous Disease, Chronic; Humans; In Vitro Techniques; Male; Membrane Potentials; Neutrophils; Onium Compounds; Superoxides; Tetradecanoylphorbol Acetate; Tetraphenylborate; Trityl Compounds; Valinomycin