Biomedical subjects

M Miwa

Publications and source records attributed to M Miwa.

At least 55 records · Page 3Linked to original sources

PubMed2000

Cyclooxygenase expression in the gallbladder.

The COX expressions were evaluated separately in the epithelium and in the stroma of gallbladder cancer, chronic cholecystitis, xanthogranulomatous cholecystitis (XGC) and the normal gallbladder. In normal gallbladder COX-2 expression rate was significantly higher in the epithelium than in the stroma. The COX-2 expression rate in the epithelium of non-cancerous adjacent epithelium to cancerous lesion was significantly lower than those not only of cancer, but also chronic cholecystitis, XGC and normal gallbladder. In stroma, the COX-2 expression rate in cancer, chronic cholecystitis and XGC were significantly higher than that of the normal gallbladder. The rate in non-cancerous adjacent stroma to cancer is significantly lower than that of cancer and XGC. However, the difference of rate between of normal and of chronic cholecystitis was not significant. The COX-2 expression rates were significantly higher in both the epithelium and the stroma in the well and moderately differentiated cancer group than in the poorly and undifferentiated cancer group. Our results suggest that COX-2 expression in the gallbladder may be regulated by various factors and not directly related to carcinogenesis. The significance of its repression in the non-cancerous adjacent tissue to cancer lesion should be re-evaluated.

Cholecystitis↗

PubMed2000

[Comparative genomic hybridization for analysis of chromosomal changes in cisplatin-resistant ovarian cancer].

In our attempt to find characteristic genetic changes in resistant tumors, we screened the whole genome for gene aberrations in 28 primary ovarian cancers, using the comparative genomic hybridization (CGH) method. These cancers included 14 tumors from patients who did not respond to cisplatin-based combination chemotherapy in comparison with 14 tumors from patients who completely responded to the chemotherapy. We found gains in chromosomal region 1q21-q22 and 13q12-q14 to be related to the drug-resistant phenotype in ovarian cancer patients. Several genes encoding transcription factors, oncogenes, cell cycle regulators and regulators of the apoptotic pathway are found to be located on these regions of the chromosomes, and these genes are potential modulators for toxic insults in cancer cells. This is the first report that shows the relationship between certain genomic aberrations and clinical resistance for cisplatin-based chemotherapy in ovarian cancer patients based on the CGH analysis. Present findings suggest that these chromosomal gains may be potential indicators for prediction of resistance in ovarian cancer patients prior to cisplatin-based chemotherapy.

Antineoplastic Agents↗

PubMed1999

Involvement of p42/p44 mitogen-activated protein kinase in prostaglandin f(2alpha)-stimulated induction of heat shock protein 27 in osteoblasts.

We previously reported that prostaglandin F(2alpha) (PGF(2alpha)) activates both phosphoinositide-hydrolyzing phospholipase C and phosphatidylcholine-hydrolyzing phospholipase D in osteoblast-like MC3T3-E1 cells and then induces the activation of protein kinase C (PKC). In this study, we investigated the effect of PGF(2alpha) on the induction of heat shock protein 27 (HSP27), a low-molecular-weight heat shock protein, in these cells. PGF(2alpha) significantly induced the accumulation of HSP27 dose-dependently within the range of 10 nM to 10 microM. PGF(2alpha) stimulated the increase in the levels of mRNA for HSP27. A total of 10 nM 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of PKC, induced the accumulation of HSP27. The stimulative effect of PGF(2alpha) was reduced in the PKC down-regulated cells. Calphostin C, a specific inhibitor of PKC, suppressed the PGF(2alpha)-induced HSP27 accumulation as well as that induced by TPA. HSP27 induction by PGF(2alpha) was reduced by U-73122, a phospholipase C inhibitor, or propranolol, a phosphatidic acid phosphohydrolase inhibitor. PGF(2alpha) and TPA stimulated p42/p44 mitogen-activated protein (MAP) kinase. PD98059, an inhibitor of the upstream kinase that activates p42/p44 MAP kinase, suppressed the induction of HSP27 stimulated by PGF(2alpha) or TPA. PD98059 and calphostin C reduced the levels of mRNA for HSP27 increased by PGF(2alpha). These results indicate that PGF(2alpha) stimulates the induction of HSP27 via p42/p44 MAP kinase activation, which depends on upstream PKC activation in osteoblasts.

Adrenergic beta-Antagonists↗

PubMed1999

Age-dependent paraparesis in WKA rats: evaluation of MHC k-haplotype and HTLV-1 infection.

Human T-cell leukemia virus type 1 (HTLV-1) infection is shown to be closely associated with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Although the occurrence of HAM/TSP was reported to be associated with MHC class II, the mechanism is still unclear. The WKA(RT1k) strain of rats was reported to develop HAM/TSP-like paraparesis after HTLV-1 infection, and was suggested to be an animal model of HAM/TSP. We asked whether MHC k-haplotype is specifically involved in the pathogenesis of paraparesis of WKA(RT1k) rats. We injected the HTLV-1 producing human T cells (MT-2 cells) intravenously into WKA(RT1k) rats and MHC congenic WKA.1L(RT1l) rats which have MHC l-haplotype of LEW rats on the WKA background. Positive antibody response to HTLV-1 antigens and presence of provirus in peripheral blood mononuclear cells confirmed that MT-2 cell-injected rats were infected with HTLV-1. Two of 13 MT-2 cell-injected WKA(RT1k) rats and five of 13 MT-2 cell-injected WKA.1L(RT1l) rats developed HAM/TSP-like hindlimb paraparesis between 16 and 26 months old. Interestingly, three of 14 MT-2 cell-uninjected WKA(RT1k) rats and four of 13 MT-2 cell-uninjected WKA.1L(RT1l) rats showed similar paraparesis between 15 and 26 months old. MHC k-haplotype is not specific to the development of paraparesis in WKA(RT1k) rats. The role of aging, genetic background, HTLV-1 infection and other factors on the development of HAM/TSP-like paraparesis in rats are discussed.

Age Factors↗

PubMed1999

Role of lecithin-cholesterol acyltransferase in the metabolism of oxidized phospholipids in plasma: studies with platelet-activating factor-acetyl hydrolase-deficient plasma.

To determine the relative importance of platelet-activating factor-acetylhydrolase (PAF-AH) and lecithin-cholesterol acyltransferase (LCAT) in the hydrolysis of oxidized phosphatidylcholines (OXPCs) to lyso-phosphatidylcholine (lyso-PC), we studied the formation and metabolism of OXPCs in the plasma of normal and PAF-AH-deficient subjects. Whereas the loss of PC following oxidation was similar in the deficient and normal plasmas, the formation of lyso-PC was significantly lower, and the accumulation of OXPC was higher in the deficient plasma. Isolated LDL from the PAF-AH-deficient subjects was more susceptible to oxidation, and stimulated adhesion molecule synthesis in endothelial cells, more than the normal LDL. Oxidation of 16:0-[1-14C]-18:2 PC, equilibrated with plasma PC, resulted in the accumulation of labeled short- and long-chain OXPCs, in addition to the labeled aqueous products. The formation of the aqueous products decreased by 80%, and the accumulation of short-chain OXPC increased by 110% in the deficient plasma, compared to the normal plasma, showing that PAF-AH is predominantly involved in the hydrolysis of the truncated OXPCs. Labeled sn-2-acyl group from the long-chain OXPC was not only hydrolyzed to free fatty acid, but was preferentially transferred to diacylglycerol, in both the normal and deficient plasmas. In contrast, the acyl group from unoxidized PC was transferred only to cholesterol, showing that the specificity of LCAT is altered by OXPC. It is concluded that, while PAF-AH carries out the hydrolysis of mainly truncated OXPCs, LCAT hydrolyzes and transesterifies the long-chain OXPCs.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed1999

Contribution of endothelin-1 to microcirculatory impairment in total hepatic ischemia and reperfusion injury.

BACKGROUND: Endothelin (ET)-1 may have a role in hepatic polymorphonuclear leukocyte infiltration as well as microcirculatory disturbance during hepatic ischemia-reperfusion (HIR) injury. This study was conducted to investigate the influence of ET-1 on the hepatic microcirculation after total HIR and to evaluate the effect of a nonselective ET receptor antagonist under these conditions. METHODS: Male rats pretreated with either normal saline (NS group) or TAK-044, a nonselective ET receptor antagonist (TAK group), were subjected to 120 min of total hepatic ischemia with extracorporeal portosystemic shunting. RESULTS: Plasma ET-1 levels increased significantly from 1 to 6 hr after reperfusion in the NS group when compared with the nonischemic control. In the early phase of reperfusion, the NS group showed significantly narrower sinusoids, lower hepatic tissue blood flow, a lower hepatic tissue oxy-hemoglobin concentration, and more hepatic neutrophil infiltration than the TAK group (P<0.05). Pretreatment with TAK-044 improved hepatic microcirculatory derangement, and resulted in significantly better 7-day survival (61.5%) with more bile production after reperfusion when compared with the NS group (P<0.01). CONCLUSIONS: The present study demonstrated that ET-1 is involved in the development of HIR injury by causing deterioration of the hepatic microcirculation. A nonselective ET receptor antagonist successfully ameliorated HIR injury through improvement of hepatic oxygenation and of the microcirculation along with reduced hepatic neutrophil infiltration.

Alanine Transaminase↗

PubMed1999

Poly(ADP-ribose) polymerase interacts with novel Drosophila ribosomal proteins, L22 and l23a, with unique histone-like amino-terminal extensions.

Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme that recognizes and binds to the nicks and ends of DNA, and catalyses successive ADP-ribosylation reactions. To clarify the function of PARP at the molecular level, we searched proteins which interact with PARP. In the auto-modification domain of PARP in Drosophila, there is a putative leucine-zipper motif which can interact with other protein molecules. To find interacting proteins we examined the auto-modification domain of Drosophila PARP, using the Far-Western screening method. From six independent cDNA clones isolated, we characterized two clones, PBP-3 and PBP-12. The predicted amino acid sequences from 109 to 269 of PBP-3 and from 184 to 312 of PBP-12 had more than 62% identities to mammalian L23a (rpl23a) and L22 (rpl22), the ribosomal proteins of the large subunit. This indicated that PBP-3 and PBP-12 are Drosophila homologues of L23a and L22, respectively. These Drosophila ribosomal protein L22 and L23a have additional Ala-, Lys- and Pro-rich sequences at the amino terminus, which have a resemblance to the carboxy-terminal portion of histone H1. Thus, Drosophila L22 and L23a might have two functions, namely the role of DNA-binding similar to histone H1 and the role of organizing the ribosome.

Amino Acid Sequence↗

PubMed1999

1q23 gain is associated with progressive neuroblastoma resistant to aggressive treatment.

Neuroblastoma is one of the most common malignant tumors of childhood and is characterized by regressive and progressive disease. Genetic factors that define progression of neuroblastomas are still unknown. We performed comparative genomic hybridization (CGH) on 27 neuroblastomas and dual-color fluorescence in situ hybridization (FISH) to identify genetic aberrations associated with progressive neuroblastoma showing resistance to aggressive treatment. 17q21-q25 gains and MYCN amplification were associated with stage 4 neuroblastomas; however, these genetic aberrations had no significant relation to the progression of stage 4 neuroblastomas. A novel chromosomal gain at 1q21-q25 was found in 8 of 16 cases (50%) of stage 4 neuroblastoma. Gain of 1q21-q25 was observed in all of the progressive cases (8/8), which showed resistance to chemotherapy, including 5 fatal neuroblastomas in stage 4, whereas 1q21-q25 gain was not found in any of the 8 remission cases in stage 4. Survival analysis also showed that 1q21-q25 gain was associated with a poor outcome. High xenotransplantability in nude mice was observed for the tumors with 1q21-q25 gain (4/5; 80%). These data show that 1q21-q25 gain is strongly associated with progression of stage 4 neuroblastoma. Furthermore, by dual-color FISH analysis using cosmid clones, the 1q21-q25 gain was narrowed to increase in DNA copy number on 1q23 in the fatal type of stage 4 neuroblastoma showing this gain. These results suggest that DNA amplification at 1q23 may play a role in the development of progressive neuroblastoma in an advanced stage.

Animals↗

PubMed1999

High-level expressing YAC vector for transgenic animal bioreactors.

The position effect is one major problem in the production of transgenic animals as mammary gland bioreactors. In the present study, we introduced the human growth hormone (hGH) gene into 210-kb human alpha-lactalbumin position-independent YAC vectors using homologous recombination and produced transgenic rats via microinjection of YAC DNA into rat embryos. The efficiency of producing transgenic rats with the YAC vector DNA was the same as that using plasmid constructs. All analyzed transgenic rats had one copy of the transgene and produced milk containing a high level of hGH (0.25-8.9 mg/ml). In transgenic rats with the YAC vector in which the human alpha-lactalbumin gene was replaced with the hGH gene, tissue specificity of hGH mRNA was the same as that of the endogenous rat alpha-lactalbumin gene. Thus, the 210-kb human alpha-lactalbumin YAC is a useful vector for high-level expression of foreign genes in the milk of transgenic animals.

Animals↗

PubMed1999

Analysis of control elements for position-independent expression of human alpha-lactalbumin YAC.

A major problem in the production of transgenic animal bioreactors using microinjections is the low production rate of high-expressing transgenic animals due to the position effect. We previously reported that transgenic rats carrying the 210 kb yeast artificial chromosome (YAC) including the human alpha-lactalbumin gene express the transgene in a position-independent manner. The 210 kb YAC was thought to have all the elements necessary for position-independent expression. In this paper, we constructed fragmented YAC clones and a cosmid clone, and produced transgenic rats to analyze these elements. Transgenic rats with both the 50 kb upstream and downstream regions of the alpha-lactalbumin gene had position-independent expression. Transgenic rats with the 20 kb upstream and downstream regions, however, had position-dependent expression. Therefore, all the elements necessary for position-independent expression are thought to be located in the 50 kb upstream to 50 kb downstream region of the alpha-lactalbumin gene. Furthermore, we replaced the human alpha-lactalbumin promoter with the bovine alphaS1-casein promoter in the 210 kb YAC and produced transgenic rats. Position-dependent expression was observed. The elements required for position-independent expression of the bovine alphaS1-casein gene are different from those required for the human alpha-lactalbumin gene, despite the fact that the two genes have the same tissue and developmental specificity.

Animals↗

PubMed1999

Role of platelet-activating factor acetylhydrolase gene mutation in Japanese childhood IgA nephropathy.

Platelet-activating factor (PAF) is a potent mediator of inflammatory injury in renal diseases. PAF is degraded to inactive products by PAF acetylhydrolase. Recently, a point mutation (G to T transversion) of the PAF acetylhydrolase gene was observed at position 994, and this mutation was found to contribute to the variability in plasma PAF levels, with undetectable plasma PAF acetylhydrolase activity occurring in homozygous patients (TT genotype) and reduced levels of activity in heterozygous patients (GT genotype). Therefore, we investigated the effect of the PAF acetylhydrolase gene mutation on the pathogenesis and progression of immunoglobulin A (IgA) nephropathy. Genomic DNA was obtained from 89 children with IgA nephropathy and 100 controls. We identified the PAF acetylhydrolase gene mutation (G994T) by polymerase chain reaction. There was no significant difference in genotypic frequency between patients and controls. However, urinary protein excretion at the time of biopsy was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. The percentage of glomeruli with mesangial cell proliferation was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. These results indicate the PAF acetylhydrolase gene mutation may influence the degree of proteinuria and the extent of mesangial proliferation in the early stage of childhood IgA nephropathy.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed1999

Tissue distribution of polaprezinc in rats determined by the double tracer method.

The tissue distribution of polaprezinc (an insoluble zinc complex of L-carnosine) in rats was studied by the double tracer method using [U-14C-histidine]-, 65Zn-polaprezinc. The 65Zn-radioactivity was measured with an auto-gamma counter, and the 14C containing 65Zn was converted to an absolute count according to the calibration curve for quenching with a liquid scintillation counter with the spill-over method. After the administration of 14C-, 65Zn-polaprezinc to rats, the excretion ratio and time courses in the tissues of the 14C-and 65Zn-radioactivity were different each other. We found that polaprezinc was metabolized as endogenous amino acid or zinc after dissociation in the body. The zinc concentration in plasma reached its maximum at 1 h and decreased slowly, returning to the endogenous level at 11 h after the administration of non-labeled polaprezinc. The concentrations of zinc in liver, kidney, testis, prostate, and cerebrum remained rather constant. The replacement ratios of 65Zn to zinc in the tissues at its maximum percentage were 40% in plasma, 16-20% in liver, kidney, blood, and prostate. The low replacement ratios in testis and cerebrum (2-3%) suggested that zinc uptakes in testis and brain were regulated by the blood-testis-barrier and blood-brain-barrier, respectively.

Administration, Oral↗

PubMed1999

Push/pull hemodiafiltration: technical aspects and clinical effectiveness.

Push/pull hemodiafiltration (HDF) is characterized by alternate repetition of filtration and backfiltration during hemodialysis with high-flux membrane. In the pressure-controlled push/pull (PC P/P) HDF system, which is the newest push/pull HDF system, there are about 25 repetitions of dilution and concentration of the blood while it passes through the hemodiafilter. Hence, the PC P/P is functionally close to the predilution mode of on-line HDF. In the PC P/P, body fluid is replaced usually by more than 120 L of dialysate during the 4 h treatment. In selecting a hemodiafilter for PC P/P, one must be certain that the blood flow channels in the hemodiafilter do not collapse by the positive pressure on the dialysate side in the backfiltration phase. Thus, the polyacrylonitrile hollow-fiber hemodiafilter and polysulfon hollow-fiber hemodiafilter are suitable for PC P/P. In the short term, PC P/P has been reported to be effective against joint pain, itchiness, insomnia, irritability, and restless leg syndrome experienced by hemodialysis patients. Midterm clinical effectiveness of PC P/P includes the requisite lowering of the erythropoietin dose and improvement in skin pigmentation. The albumin loss per treatment with the PC P/P was significantly lower than that with the conventional HDF approach when a protein-permeable membrane is used. In terms of the removal rate of prolactin, no significant difference was found between PC P/P and conventional HDF. On the other hand, the removal rates of myoglobin and beta2M, where molecular size was smaller than prolactin, was significantly greater with the PC P/P than with conventional HDF.

Equipment Design↗

PubMed1999

Application of near-infrared time-resolved spectroscopy to rat liver--a preliminary report for surgical application.

The applicability of near-infrared time-resolved spectroscopy to rat liver surgery was investigated. First, the technical reliability in determining the absorption coefficient (mu(a)) and reduced scattering coefficient (mu'(s)) of the liver was checked. Next, boundary effects in determining mu(a) and mu'(s) of the rat liver were examined. Finally, changes in mu(a) and mu'(s) of rat liver with ischaemia were directly measured by TRS. Our TRS system showed that the mu(a) value held a linear correlation with the ink concentration in a lipid emulsion until mu(a) reached 1.2 cm(-1), while the mu'(s) was fairly independent. The mu(a) values of blood-free rat liver and blood-containing rat liver at 780 nm were observed to be 0.43 cm(-1) and 0.67 cm(-1) by using the matching method, indicating that TRS is reliable in determining mu(a) and mu'(s) of the liver. Possible errors in mu(a) and mu'(s) determination due to the boundary effects of the rat liver were as small as 7%, when the mu(a) value was as high as observed for the liver. The oxygen saturation of haemoglobin (SO2) was changed from 64.9% to 8.0%, and the haemoglobin content (THB) from 189.1 microM to 131.6 microM by ischaemia. Mu'(s) dynamically changed in the range 7.06 cm(-1) to 11.36 cm(-1). We conclude that time-resolved measurement is applicable in the high-mu(a) region observed in the liver, and can give quantitative estimations of SO2 and THB in the liver.

Animals↗

PubMed1999

Human T-cell leukemia virus type 1 can infect a wide variety of cells in mice.

Analysis of human T-cell leukemia virus type 1 (HTLV-1)-infected cell types and the interplay of these infected cells in vivo should provide valuable information to elucidate the pathogenesis of HTLV-1-associated diseases in humans and in animal models. In this study, HTLV-1-infected cell types were identified in HTLV-1-infected C3H/HeJ mice. Pan T, CD4+, CD8+, granulocyte and pan B cell fractions in the splenocytes of MT-2 cell-inoculated mice were sorted by use of their cell surface high-density expression of CD3e, CD4, CD8, Gr-1 and B220 antigens, respectively, with a fluorescence-activated cell sorter. The pX sequence of HTLV-1 provirus in the lysate of each fraction was amplified by polymerase chain reaction and detected by Southern hybridization. Interestingly, in addition to the CD4+ cell fraction, the pX sequence was also found in CD8+ cell, B cell and granulocyte fractions. The broad cell spectrum of HTLV-1 infection in mice is consistent with the situation in humans. Our finding indicate that HTLV-1 receptor or coreceptor is widely distributed among different cell types in mice.

Animals↗

PubMed1999

All ApoB-containing lipoproteins induce monocyte chemotaxis and adhesion when minimally modified. Modulation of lipoprotein bioactivity by platelet-activating factor acetylhydrolase.

Mildly oxidized LDL has many proinflammatory properties, including the stimulation of monocyte chemotaxis and adhesion, that are important in the development of atherosclerosis. Although ApoB-containing lipoproteins other than LDL may enter the artery wall and undergo oxidation, very little is known regarding their proinflammatory potential. LDL, IDL, VLDL, postprandial remnant particles, and chylomicrons were mildly oxidized by fibroblasts overexpressing 15-lipoxygenase (15-LO) and tested for their ability to stimulate monocyte chemotaxis and adhesion to endothelial cells. When conditioned on 15-LO cells, LDL, IDL, but not VLDL increased monocyte chemotaxis and adhesion approximately 4-fold. Chylomicrons and postprandial remnant particles were also bioactive. Although chylomicrons had a high 18:1/18:2 ratio, similar to that of VLDL, and should presumably be less susceptible to oxidation, they contained (in contrast to VLDL) essentially no platelet-activating factor acetylhydrolase (PAF-AH) activity. Because PAF-AH activity of lipoproteins may be reduced in vivo by oxidation or glycation, LDL, IDL, and VLDL were treated in vitro to reduce PAF-AH activity and then conditioned on 15-lipoxygenase cells. All 3 PAF-AH-depleted lipoproteins, including VLDL, exhibited increased stimulation of monocyte chemotaxis and adhesion. In a similar manner, lipoproteins from Japanese subjects with a deficiency of plasma PAF-AH activity were also markedly more bioactive, and stimulated monocyte adhesion nearly 2-fold compared with lipoproteins from Japanese control subjects with normal plasma PAF-AH. For each lipoprotein, bioactivity resided in the lipid fraction and monocyte adhesion could be blocked by PAF-receptor antagonists. These data suggest that the susceptibility of plasma lipoproteins to develop proinflammatory activity is in part related to their 18:1/18:2 ratio and PAF-AH activity, and that bioactive phospholipids similar to PAF are generated during oxidation of each lipoprotein. Moreover, LDL, IDL, postprandial remnant particles, and chylomicrons and PAF-AH-depleted VLDL all give rise to proinflammatory lipids when mildly oxidized.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed1999

Mitogen-activated protein (MAP) kinases are involved in interleukin-1 (IL-1)-induced IL-6 synthesis in osteoblasts: modulation not of p38 MAP kinase, but of p42/p44 MAP kinase by IL-1-activated protein kinase C.

We previously reported that interleukin-1alpha (IL-1alpha)-induced activation of protein kinase C (PKC) via phosphatidylcholine-specific phospholipase C (PC-PLC) limits IL-6 synthesis induced by IL-1alpha itself in osteoblast-like MC3T3-E1 cells. In the present study, we further investigated the mechanism behind IL-1alpha-induced IL-6 synthesis in MC3T3-E1 cells. IL-1alpha time-dependently stimulated the phosphorylation of both p42/p44 mitogen-activated protein (MAP) kinase and p38 MAP kinase. PD98059, a specific inhibitor of the upstream kinase that activates p42/p44 MAP kinase, inhibited the IL-1alpha-induced IL-6 synthesis as well as the phosphorylation of p42/p44 MAP kinase induced by IL-1alpha. SB203580, a specific inhibitor of p38 MAP kinase, also reduced both the phosphorylation of p38 MAP kinase and the IL-6 synthesis. 1-Oleoyl-2-acetylglycerol, an activator of PKC, suppressed the IL-1alpha-induced IL-6 synthesis. Calphostin C, a specific inhibitor of PKC, or D-609, a specific inhibitor of PC-PLC, significantly enhanced the IL-1alpha-induced phosphorylation of p42/p44 MAP kinase without affecting the phosphorylation of p38 MAP kinase. The phosphorylation of p42/p44 MAP kinase by IL-1alpha was markedly increased in PKC-down-regulated MC3T3-E1 cells. Neither 12-O-tetradecanoylphorbol-13-acetate, known to be an activator of PKC, nor 1-oleoyl-2-acetylglycerol affected the phosphorylation of p38 MAP kinase induced by IL-1alpha. These results strongly suggest that IL-1alpha-induced IL-6 synthesis is mediated via activations of both p42/p44 MAP kinase and p38 MAP kinase in osteoblasts, and that PKC activated by IL-1alpha itself negatively regulates IL-6 synthesis at a point upstream from p42/p44 MAP kinase.

Animals↗

PubMed1999

Ca2+/calmodulin-dependent protein kinase II inhibitors potentiate superoxide production in polymorphonuclear leukocytes.

The possible role of Ca2+/calmodulin-dependent protein kinase II (CaMK II) in superoxide anion (O2-) production induced by formyl-methionyl-leucyl-phenylalanine (FMLP) was investigated in mouse polymorphonuclear leukocytes (PMNs). KN-93 and KN-62, specific CaMK II inhibitors, augmented FMLP-induced O2- production. KN-92, an analogue which did not inhibit CaMK II, did not affect O2- production. W-7, a calmodulin inhibitor, augmented O2- production when administered at 30 mM for 5 min. KN-93 and recombinant mouse tumour necrosis factor-alpha (rmTNF-alpha) each augmented the maximal production of O2- induced by FMLP, and an additive effect of a combination of KN-93 and rmTNF-alpha was observed. CaMK II activity in the PMNs was increased by FMLP, and the increase was inhibited by KN-93 but not by rmTNF-alpha. These results suggest that the inhibition of CaMK II resulted in the augmentation of FMLP-induced O2- production in PMNs by a mechanism different from that of the augmentation shown by TNF-alpha.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗