Pharmacological Studies on the Role of Protein Kinase C in Signal Transduction of Human Basophils

Amon, Ulrich; Stebut, Esther von; Dietz, Katharina; Bauer, F.W.; Wolff, Helmut H.

doi:10.1159/000236210

Cited by 12 publications

(11 citation statements)

References 16 publications

(25 reference statements)

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“…2). The dose-depen dent increase in histamine release was not accompanied by release of lactate dehydroge nase [9].…”

Section: Experiments With Pkc Inhibitorsmentioning

confidence: 78%

“…Peripheral basophils were isolated after venipuncture from healthy donors by dextran sedimentation as previously described [9,17], In some experiments buffy coats resulting from dextran sedimentation (4 ml) were layered on top of 3 ml Ficoll-Paque (Pharmacia, Uppsala, Sweden) in 12-ml conical plastic tubes (Sarstedt) and centrifuged at 300 g for 25 min (room temperature). The lymphocyte/monocyte/basophil fraction at the interface was diluted with buffer A to 10 ml and was incubated for 10 min (room temperature, turntable) with 200 pi of CD2+, CD9+ and CD 19+ immunomagnetic beads (Dynal, Hamburg, Germany) to reduce T cells, mono cytes, macrophages, and B cells by a magnetic particle concentrator (Dynal).…”

Section: Introductionmentioning

confidence: 99%

“…The cellular and the supernatant fractions were stored at -2 0°C until determination. Histamine release was de termined in both supernatants and cell pellets using a fluorometric autoanalyzer [9,17]. Histamine release was expressed as a percentage of the total histamine initially in the cells, corrected for the spontaneous release occurring in the absence of secretagogue.…”

Section: Introductionmentioning

confidence: 99%

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Heterogeneity of Human Skin Mast Cells and Human Basophils

Amon¹,

Dieckmann²,

Nitschke³

et al. 1996

Skin Pharmacol Physiol

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Skin mast cells and basophilic leukocytes are known as key elements of acute and subacute IgE-mediated immune responses of the skin. The present paper investigated pharmacological aspects of signal transduction pathways of both cell types using activators and inhibitors of protein kinase C (PKC). The nonselective inhibitor K252a suppressed Fc_εRI-mediated histamine release from basophils and skin mast cells dose-dependently with IC₅₀ values of 0.01 and 0.28 μmol/l. However, preincubation of both cell populations with kinase inhibitors showing in vitro selectivity for PKC (Ro 31-7549, calphostin C, GF 109203X) revealed a distinct modulation of cell response: IgE-mediated mediator release was inhibited only in skin mast cells, whereas in experiments with basophils a concentration-dependent potentiation of exocytosis was observed. Further evidence for heterogenous biochemical signals following activation of both cell types derived from studies with the phorbol ester TPA. With respect to acute and late-phase IgE-mediated skin reactions, we suggest that distinct signal transduction mechanisms at the level of PKC (isozymes) in basophils and skin mast cells might reflect their functional heterogeneity.

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“…2). The dose-depen dent increase in histamine release was not accompanied by release of lactate dehydroge nase [9].…”

Section: Experiments With Pkc Inhibitorsmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Heterogeneity of Human Skin Mast Cells and Human Basophils

Amon¹,

Dieckmann²,

Nitschke³

et al. 1996

Skin Pharmacol Physiol

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“…In the case of a unidirectional cascade of receptor aggregation -> PKC activation -* exocytosis, excessive stimulation of atopic basophils in vivo via the high-affinity IgE receptor Fc,RI would be a suitable explanation for the decreased reactivity towards PKC activators. Very recently it has been shown that selective PKC inhibitors can poten tiate the IgE-mediated histamine release from human baso phils, suggesting a negative regulatory function of PKC in this pathway [10]. Down-regulation or desensitization of basophil PKC due to continuous allergen exposure in vivo may therefore lead to a reduced control function for IgEmediated histamine release, resulting in enhanced releas- ability, and to a reduced activation after incubation with PKC activators, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…Basophils were isolated from venous blood by dextran sedimenta tion as previously described [10]. Leukocyte suspensions (approx.…”

Section: Preparation O F Basophilsmentioning

confidence: 99%

Influence of Protein Kinase C Activation on Basophils from Patients with Atopic Dermatitis in Comparison with Nonatopic Controls

Amon¹,

Stebut²,

Ramachers³

et al. 1993

Dermatology

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Protein kinase C (PKC) is suggested to be important for signal transduction of histamine-containing cells. The present study investigated the putative role of PKC in enhanced mediator release of basophils in atopic derm atitis (AD). Basophils were isolated from patients with severe AD (mean serum IgE level of 5,165 U/ml) and from healthy controls, and the effects of potent activators of PKC on histamine release were studied. The phorbol esters 12-o-tetradecanoyl-phorbol-13-acetate and phorbol-12,13-dibutyrate and the nonphorbol mezerein induced a dose-dependent mediator release, which was significantly lower in ‘atopic’ basophils at concentrations ≥1 μM. Recently, PKC levels have been shown to be lowered in atopic leukocytes compared to cells from healthy controls. The lowered response of PKC towards direct activation and lowered PKC levels may be due to high serum IgE levels and allergen exposure in vivo with subsequent down-regulation of different key elements of signal transduction.

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Pharmacological investigations with different protein kinase C inhibitors on IgE-dependent and IgE-independent activation of human basophils

1993

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In the present study different selective inhibitors of the multifunctional serine/threonine kinase protein kinase C (PKC) were investigated on classical activation pathways of basophils in comparison to the nonselective protein kinase inhibitor staurosporine. The potent inhibitors Ro 31-7549, Ro 31-8220, calphostin C and ilmofosine (BM 41.440), which show selectivity for PKC in vitro, significantly potentiated Fc epsilon RI-mediated histamine release up to 50% vs. controls at concentrations > 10(-7) mumol/l but were without any intrinsic histamine releasing activity. Direct activation of cellular PKC by phorbol ester was suppressed by all compounds apart from ilmofosine at the same concentrations. We did not observe statistically significant effects of selective PKC inhibitors on exocytosis induced by the peptide formylmeth-leu-phe (FMLP) or the ionophore A23187, whereas staurosporine potentiated the FMLP-induced histamine release in a dose-dependent fashion: maximum potentiation was 63.5 +/- 8.9% vs. control at 1 mumol/l (n = 4). The findings suggest that PKC exhibits differential functions during biochemical events of stimulus-secretion coupling in human basophils supposedly by its distinct subtypes. With respect to the present data, TPA-induced and IgE-mediated signals are not closely correlated.

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Pharmacological Studies on the Role of Protein Kinase C in Signal Transduction of Human Basophils

Cited by 12 publications

References 16 publications

Heterogeneity of Human Skin Mast Cells and Human Basophils

Heterogeneity of Human Skin Mast Cells and Human Basophils

Influence of Protein Kinase C Activation on Basophils from Patients with Atopic Dermatitis in Comparison with Nonatopic Controls

Pharmacological investigations with different protein kinase C inhibitors on IgE-dependent and IgE-independent activation of human basophils

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