Differential expression of protein kinase C genes in cultured mast cells derived from normal and mast-cell-deficient mice and mast cell lines

Promoted expression of mast cell-specific proteases in IgE-dependent passive cutaneous anaphylaxis responses

BACKGROUND

Various factors can influence the protease expression phenotype of mast cells.

METHODS

In an effort to understand the potential role of the mast cell proteases in the IgE-dependent passive cutaneous anaphylaxis (PCA) responses of murine tissues, we studied the changes of proteases expression. The expressions of proteases were examined by Northern blotting and immunohistochemistry.

RESULTS

Promoted expression phenotypes of mouse mast cell protease (mMCP)-4, and rat mast cell protease I were accompanied by initiation of anti-dinitrophenyl (DNP) IgE-induced PCA responses, suggesting that the induction of these proteases expression are associated with IgE-mediated anaphylaxis responses. Elevated level of the L-histidine decarboxylase (HDC) mRNA expression was also observed in the PCA tissues and the activated mast cells, compared with that of the corresponding control tissue and cells, due to the activation of mast cells.

CONCLUSIONS

Promoted protease expression phenotype appears to be linked with the induction of HDC expression.

Phosphatidylinositol 3-kinase regulates proliferation of RAW 264.7 macrophages

Phosphatidylinositol 3-kinase (P13-kinase) is an enzyme that acts as a direct biochemical link between a novel phosphatidylinositol pathway and a number of proteins containing intrinsic or associated kinase activities. Here we demonstrate that wortmannin, P13-kinase inhibitor, decreases the proliferation of RAW 264.7 macrophages and that another structurally unrelated inhibitor of P13-kinase, LY294002. also inhibits the proliferation. These results indicate a possible involvement of P13-kinase in RAW 264.7 macrophages growth regulation. Wortmannin stimulation of RAW 264.7 macrophages is followed by sustained expression of the mRNA of c-fos and a transient expression of the mRNA of c-jun. We also show that the wortmannin and LY294002 induce a cell cycle arrest in asynchronously growing cells leading to an inhibition of cell proliferation after 12 h of treatment. In addition, wortmannin or LY294002 inhibited the phorbol 12-myristate 13-acetate-induced macrophages proliferation potently. These results suggest that P13-kinase plays an important role in growth regulation of RAW 264.7 macrophages and that protein kinase C is a down stream effector of P13-kinase.

Expression of protein kinase C genes in normal (+/+) and W mutant alleles (Wsh/Wsh, W/Wv) mice testes

In the present study, we investigated the expression of mRNA of protein kinase C (PKC) isoenzymes (alpha, beta, gamma, delta, epsilon, zeta, eta, and theta) in normal (+/+) and W mutant alleles mice testes. In +/+ mice testes, abundant expression of PKCdelta and PKCtheta was observed, while other PKCs (alpha, beta, gamma, epsilon, zeta, and eta) generally were not detected by Northern blotting. The PKCdelta and PKCtheta isoenzymes demonstrated a distinctive cellular distribution when evaluated by in situ hybridization. We have previously shown that PKCdelta gene was selectively expressed in spermatid of +/+ testes. Here we show that PKCdelta gene is also present in spermatid of Wsh/Wsh mice testes and PKCtheta gene was present in interstitial cells of +/+, Wsh/Wsh, and W/Wv mice testes. These studies provide the evidence of selective cell distributions of the PKC isoenzymes and suggest that PKC has the functional significance in testes.

Interleukin-3 or immunoglobulin E promotes expression of protein kinase C delta gene in murine mast cells

We reported previously that protein kinase C delta (PKCdelta) is the main isoenzyme in various types of murine mast cells. In the present study we investigated the regulation of expression of PKCdelta gene in murine mast cells in vitro and in vivo. The mRNA expressions of PKCdelta were promoted in response to interleukin-3 (IL-3) or immunoglobulin E (IgE) in mouse mastocytoma P-815 cells. In addition we have evaluated the mast cells which express PKCdelta mRNA in IgE-dependent passive cutaneous anaphylaxis reaction, using in situ hybridization with the antisense riboprobe in skin. These results indicate that mast cell activation can induce a marked promotion in steady state levels of PKCdelta mRNA.

Inhibition of mast cell-dependent anaphylaxis by sodium salicylate

Sodium salicylate (NaSal) is a commonly used agent with a wide pharmacological spectrum. The objective of the present study was to investigate the effect of NaSal on anaphylaxis. NaSal (10-1 and 1 mm) significantly inhibited systemic anaphylaxis induced by compound 48/80 in rats. NaSal also significantly inhibited local anaphylaxis activated by anti-dinitrophenyl (DNP) immunoglobulin E (IgE). NaSal (10-1 and 1 mm) significantly inhibited histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. Northern-blot analysis demonstrated that a significantly reduced level of the mRNA of L-histidine decarboxylase was expressed in mast cells treated with NaSal, compared with that without NaSal. NaSal (10-2 and 10-1 mm) had a significant inhibitory effect on anti-DNP IgE-induced tumour necrosis factor-alpha secretion from RPMC. The level of cyclic AMP in RPMC, when NaSal (1 mm) was added, transiently and significantly increased about sixfold compared with that of basal cells. These results suggest a possible use of NaSal in managing mast cell-dependent anaphylaxis.

Differential localization and expression of alpha and beta isoenzymes of protein kinase C in the rat retina

Expression and cellular localization of three isoenzymes of Ca2+-dependent protein kinase C (PKCalpha, PKCbeta, and PKCgamma) in the adult rat retina were revealed by immunohistochemistry and in situ hybridization histochemistry with isoenzyme-specific antibodies and cRNA probes. Immunoreactivities and mRNA signals for PKCalpha were conspicuous in rod bipolar cells. A subgroup of amacrine cells expressed PKCalpha. The cells in the ganglion cell layer also displayed PKCalpha gene products. Positive immunoreactivities for PKCbeta were localized as stripe patterns in the inner plexiform layer, corresponding to the stratification levels of axon terminals of cone bipolar cells. The somata of cone bipolar cells expressed PKCbeta. Amacrine cells and retinal ganglion cells also displayed PKCbeta gene products. The results obtained by immunohistochemistry were confirmed with colocalization of mRNA signals for PKCalpha and PKCbeta on the somata. The cell membranes showed stronger immunoreactivities than did the cytoplasms for both PKCalpha and PKCbeta. Neither immunoreactivities nor mRNA signals for PKCgamma were detected in all retinal regions. The differential roles of Ca2+-dependent PKC isoenzymes could be revealed in physiological defined retinal neurons.

Inhibition of the induction of the inducible nitric oxide synthase in murine brain microglial cells by sodium salicylate

The induction of the inducible nitric oxide synthase (iNOS) has been proposed to play a role in a variety of inflammatory diseases. Sodium salicylate (NaSal) is the most commonly used anti-inflammatory agent. We investigated whether NaSal can diminish the induction of iNOS in murine brain microglial cells. In primary cultures, interferon-gamma (IFN-gamma) or lipopolysaccharide (LPS) separately did not stimulate nitric oxide (NO) production, whereas IFN-gamma combined with LPS synergistically induced iNOS. NaSal inhibited both the production of NO and expression of iNOS in microglial cells. Synergy between IFN-gamma and LPS was mainly dependent on tumour necrosis factor-alpha (TNF-alpha) secretion as the increase of the induction of the iNOS by IFN-gamma plus LPS was associated with the increase of TNF-alpha secretion and IFN-gamma plus LPS-induced TNF-alpha secretion by microglial cells was decreased by the treatment with NaSal. These results suggest a possible use of NaSal in managing inflammation of the central nervous system through inhibition of the iNOS induction.

Specific inhibition of immunoglobulin E-mediated allergic reaction using antisense Fc epsilon RI alpha oligodeoxynucleotides

We have investigated the ability of an antisense immunoglobulin E (IgE) receptor alpha-subunit oligodeoxynucleotide (Fc epsilon RI alpha ODN) specifically to inhibit IgE-mediated allergic reactions in the mouse. Synthetic antisense Fc epsilon RI alpha ODN dose-dependently inhibited passive cutaneous anaphylaxis and histamine release from the mouse peritoneal mast cells (MPMC) activated by anti-dinitrophenyl (DNP) IgE. Northern blot analysis showed that the mast cells treated with antisense Fc epsilon RI alpha ODN exhibited no detectable levels of L-histidine decarboxylase mRNA after anti-DNP IgE stimulation, whereas the cells treated with sense Fc epsilon RI alpha ODN possessed significant amounts of this mRNA. Examination of the elevation of cAMP levels in MPMC following the activation with anti-DNP IgE demonstrated a significant rise in activated cells, but not in the antisense Fc epsilon RI alpha ODN-treated cells. Moreover, antisense Fc epsilon RI alpha ODN had a significant inhibitory effect on anti-DNP IgE-induced tumour necrosis factor-alpha production. Our results demonstrated that antisense Fc epsilon RI alpha ODN inhibited the IgE-mediated allergic reaction in vivo and in vitro.

Solanum lyratum inhibits anaphylactic reaction and suppresses the expression of L-histidine decarboxylase mRNA

We investigated the effect of aqueous extract of Soloanum lyratum THUNB. (Solanaceae) (SLAE) on anaphylactic reaction. The mast cell is widely thought to contribute to the acute changes associated with anaphylaxis. SLAE inhibited skin mast cells-mediated anaphylactic reaction activated by anti-dinitrophenyl (DNP) IgE. SLAE dose-dependently inhibited histamine release in mouse peritoneal mast cells activated by anti-DNP IgE or substance P. Substance P increased steady state levels of L-histidine decarboxylase (HDC) mRNA in mouse mastocytoma P-815 cells. Northern-blot analysis demonstrated that significantly reduced level of the mRNA of HDC was expressed in mast cells treated with SLAE, compared to that without SLAE. We conclude that SLAE directly affect IgE-mediated anaphylactic reaction and substance P-induced HDC mRNA over-expression.

Activation of inducible nitric oxide synthase by human choriogonadotropin in RAW 264.7 cells

Although human choriogonadotropin (hCG) plays a crucial role in the regulation of the menstrual cycle and maintenance of pregnancy, little is known about the other functions. However, recently hCG receptors have been identified in nongonadal cells. The objective of the current study was to determine the effect of hCG on the production of nitric oxide (NO). Stimulation of RAW 264.7 cells with hCG after treatment with recombinant interferon-gamma (rIFNgamma) resulted in increased NO synthesis. hCG had no effect on NO synthesis itself. NO production was inhibited by N(G)-monomethyl-L-arginine. rIFNgamma in combination with hCG showed marked increase of the expression of the inducible nitric oxide synthase (iNOS) gene. In addition, synergy between rIFNgamma and hCG was mainly dependent on hCG-induced tumor necrosis factor-alpha (TNF-alpha) secretion. All the preparations of hCG were endotoxin free. These results suggest that the capacity of hCG to increase NO production from rIFNgamma-primed RAW 264.7 cells is the result of hCG-induced TNF-alpha secretion.

Suppression of L-histidine decarboxylase mRNA expression by methyleugenol

We investigated the effect of methyleugenol on anaphylaxis. Methyleugenol completely inhibited systemic anaphylaxis induced by compound 48/80 in mice. Methyleugenol also inhibited local anaphylaxis activated by anti-dinitrophenyl (DNP) IgE. Moreover, methyleugenol dose-dependently inhibited histamine release in mast cells activated by compound 48/80 or anti-DNP IgE. Northern-blot analysis demonstrated that significantly reduced level of the mRNA of L-histidine decarboxylase (HDC) was expressed in mast cells treated with methyleugenol, compared to that without methyleugenol. We conclude that methyleugenol directly affect histamine release and HDC gene over-expression in mast cells.