Cocaine-induced CREB phosphorylation and c-Fos expression are suppressed in Parkinsonism model mice

Cocaine exerts multiple neurochemical effects in the central nervous system through inhibition of the dopamine transporter at the synapse. Here we report that systemic administration of the drug induces rapid phosphorylation of CREB in the mouse striatum where expression of the nuclear proto-oncogene c-fos is observed. In MPTP-treated mice, in which dopaminergic neurones are degenerated and which show Parkinsonism-like behaviour, however, CREB phosphorylation is not induced by cocaine exposure and c-fos expression is significantly depressed in comparison with controls. These data suggest that CREB may play a major role in the dopaminergic activation of c-fos in the striatum and that the lack of a CREB-induced transcription cascade may have a critical relevance for long-lasting psychomotor disorders in Parkinsonism.

[Morphological analysis of the proximal femur by computed tomography in Japanese subjects]

In order to evaluate the morphological features of the proximal femur in the Japanese, 100 femora of normal Japanese subjects (normal group) and 60 femora of 43 Japanese patients with secondary osteoarthrosis of the hip (OA group) were analyzed using CT images. The scans for the dried bones (normal group) were done at a setting of 80 kV and 20 mA, for 2 sec duration. The scans were reconstructed using the soft tissue algorithm built into the GE-9800 scanner. The patient scans (OA group) were done at 120 kV and 170 mA also for 2 sec duration, and reconstructed using the same bone algorithm. The results were as follows: 1) Thinning of the femoral cortex occurred in normal females over 60 years of age. 2) The canal flare index at the proximal part of the femoral diaphysis was negatively correlated with the canal diameter at the isthmus. The index at the upper part was greater than that at the lower part. The two groups showed no statistical difference in this index. 3) In the metaphysis, the canal flare index at the anterior portion was twice that at the posterior portion. In absolute terms, the OA group had a reduced flare or curve along the medial portion. 4) In cross-section, the canal shape of the diaphysis was more elliptical in the OA group than in the normal group. The longitudinal axis of the canal was directed more sagittally in the OA group than in the normal group.

Nitric oxide induces c-fos gene expression via cyclic AMP response element binding protein (CREB) phosphorylation in rat retinal pigment epithelium

We have examined whether nitric oxide (NO) induces the expression of c-fos proto-oncogene and the phosphorylation of cyclic AMP response element binding protein (CREB) in the rat retina. NO donor sodium nitroprusside (SNP) was injected into the vitreal cavity of the eye, and the retina and retinal pigment epithelium (RPE) was analysed by in situ hybridization using single-stranded RNA probes for c-fos transcripts and by immunocytochemistry using an anti-phospho Ser-133 antibody 20 min after the injection of SNP, phosphorylated-CREB immunoreactivity was found in RPE cells and weakly in some cells of the INL. Forty-five min after the SNP injection, the expression of c-fos mRNA was detected in the RPE. These results suggested that NO induced the c-fos expression via the phosphorylation of CREB in RPE cells, as it has been demonstrated in PC12 cells that the transcription of c-fos gene was activated by the CREB phosphorylation.

Light-induced CREB phosphorylation and gene expression in rat retinal cells

The signal pathway for light-induced expression of c-fos and the neuropeptide somatostatin (SS) in rat retinal cells was investigated. Flashing light induced c-fos and SS mRNA in the inner nuclear layer and the ganglion cell layer. As both c-fos and SS genes have a cyclic AMP response element (CRE) in their promoters, CRE-binding protein (CREB) phosphorylation in retinal cells was examined with a phospho-CREB-specific antibody. Both flashing light and administration of the L-type Ca2+ channel activator Bay K 8644 induced phosphorylation of CREB in the nuclei of the amacrine cells and the ganglion cells where c-fos/SS mRNAs were expressed. These cells could be double-stained with anti-calmodulin kinase II (anti-CaM kinase II) monoclonal antibody and phospho-CREB-specific polyclonal antiserum after Bay K 8644 administration, indicating the colocalization of phosphorylated CREB at Ser133 and CaM kinase II in the neural retina.

Lactam-conformationally restricted analogs of N alpha-arylsulfonyl arginine amide: design, synthesis and inhibitory activity toward thrombin and related enzymes

Three new lactam-conformationally restricted arginine derivatives, 1-butyl-3-(6,7-dimethoxy-2-naphthylsulfonyl)-3-(3-guanidinoprop yl)-substituted gamma-, delta-, and epsilon-lactams (2-4), were synthesized on the basis of backbone modification of the lead structure, 6,7-dimethoxy-2-naphthylsulfonylarginine n-butylmethylamide (1). We tested these compounds for inhibitory activity toward thrombin and other trypsin-like enzymes (trypsin, factor Xa, plasmin, and kallikrein). All the compounds synthesized (1-4) potently inhibited thrombin with IC50 values of 0.75, 0.70, 0.92, and 3.2 microM, respectively; they inhibited thrombin over 40-fold more effectively than the other enzymes tested. The gamma-lactam (2) with the most profound inhibitory activity toward thrombin was a reversible inhibitor with a Ki of 0.26 microM. Compound 2 also showed better thrombin selectivity than the lead compound (1). The lactam-conformational restriction of arylsulfonylarginine amides, especially gamma-lactam, has thus proved to be a useful device for the improvement of antithrombotic activity.

Calcium-induced platelet aggregation in washed platelets from guinea pigs

The present study investigated the effects of extracellular calcium on washed platelets of guinea pigs, rabbits, rats and humans. CaCl2 without agonists induced platelet aggregation in guinea pigs and rabbits, but not in rats or humans. CaCl2 increased platelet [Ca2+]i in Fura-2-loaded guinea pig platelets. Calcium-induced platelet aggregation was inhibited by W-7 (a calmodulin antagonist), aspirin, indomethacin, TMB-8 (an inhibitor of intracellular Ca2+ release) and also nicardipine (a calcium antagonist). These data suggest that CaCl2-induced platelet aggregation is mediated by calmodulin, cyclooxygenase and other, as yet unknown, mechanisms.

Functional movements of putative jaw muscle insertions

BACKGROUND

The craniomandibular muscles control jaw position and forces at the teeth and temporomandibular joints, but little is known regarding their biomechanical behaviour during dynamic function. The objective of this study was to determine how jaw muscle insertions alter position during different jaw movements in living subjects.

METHODS

Computer 3D reconstruction of MR images and jaw-tracking were combined to permit the examination of movement with six degrees of freedom. Maximum mandibular opening, protrusive and laterotrusive positions were recorded in four subjects, and the translation and rotation of the putative insertions of masseter, temporal, medial, and lateral pterygoid muscles were measured.

RESULTS

The sizes and shapes of regional attachments varied markedly among subjects, and their displacement patterns were different in specific muscles. For instance, when the jaw closed to the dental intercuspal position from maximum gape, the region near the superior insertion site of the masseter moved backward and upward, whereas the region near the inferior insertion site displaced mainly forward. In three subjects, the jaw's rotational center during this act was approximately 26-34 mm below the mandibular condyles.

CONCLUSIONS

Since the movements of each muscle part differ according to variations in the size and shape of insertion areas, individual musculoskeletal form, and patterns of jaw motion during function, the prediction of motion-related muscle mechanics in any one subject is unlikely to be possible without direct measurement of the motion of visualized muscle parts. The present study shows that this information can be obtained.

The monoclonal antibody specific for the 4-hydroxy-2-nonenal histidine adduct

Monoclonal antibodies directed against proteins modified with the major membrane lipid peroxidation product, 4-hydroxy-2-nonenal, have been established and characterized. The monoclonal antibodies specific for HNE-modified proteins were raised by immunizing mice with a HNE-keyhole limpet hemocyanin conjugate. The resulting five monoclonal antibodies (mAbs HNEJ-1-5) recognized HNE-modified bovine serum albumin (BSA), but not native BSA in Western blot studies. Of the five mAbs, HNEJ-2 exhibited the highest affinity for HNE-modified proteins and a much higher affinity for the HNE-histidine adduct than the HNE-lysine or HNE-cysteine adducts. mAb HNEJ-2 did not cross-react with proteins that had been treated with other aldehydes, such as 1-hexenal, 2-hexenal, 4-hydroxy-2-hexenal, 2-nonenal, formaldehyde, or glutaraldehyde. These results suggest that the major epitope recognized by mAb HNEJ-2 is the Michael addition-type HNE-histidine adduct.

Anti-(glioma surface antigen) monoclonal antibody G-22 recognizes overexpressed CD44 in glioma cells

We raised an anti-glioma monoclonal antibody, named G-22, that specifically recognizes a human glioma-associated surface antigen. Proven to be useful for target imaging of malignant gliomas after radioisotope labeling and cerebrospinal fluid diagnosis by enzyme-linked immunospecific assay, G-22 was found to immunoprecipitate an 85-kDa glycoprotein of the human glioma U-251MG cell. We purified this antigen by G-22-coupled cyanogenbromide-activated Sepharose affinity chromatography, and sequence analysis demonstrated that the 54 amino acid residues were identical to positions 55-108 of human CD44. The results show that the smallest spliced form (85 kDa) of CD44 is strongly expressed in glioma cells.

Platelet protein kinase C levels in Alzheimer's disease

Alzheimer's disease (AD) has been suggested to be a systemic disease, and signal transduction abnormalities have been reported in non-neuronal AD cells. We have previously quantified the protein kinase C (PKC) subtypes in AD and control brains using a two-site enzyme immunoassay (EIA), and have shown that type II PKC levels were significantly reduced in the temporal cortex of AD patients. In this study, we used this EIA to assess the platelet levels of type II PKC in age-matched groups of AD patients and normal controls. The cytosolic level of type II PKC was significantly higher in AD platelets than in control platelets but was unchanged in the membranous fraction. Platelet proteins showed no differences between the AD and control groups. Therefore, the type II PKC content of the cytosolic fraction was increased in AD platelets. These results suggest that type II PKC may be altered in both the brain and platelets of AD patients and support the hypothesis that AD is a systemic disease.

Serial changes of n-isopropyl-p-iodoamphetamine single photon emission computed tomography in two epileptic psychotics

Serial changes of single photon emission computed tomography (SPECT) in two epileptic psychotics are reported. One patient had a decreased blood flow of the left temporal lobe with schizophrenia-like symptoms, and the other patient had a decreased blood flow of the right temporal lobe with depressive symptoms. In each case, these abnormal findings disappeared following recovery from a psychotic state. It might be suggested that the psychotic state of an epileptic patient influences the SPECT findings.

Synthetic dipeptide, N-stearoyl-D-Ser-L-Pro-OEt, induces release of tissue-type plasminogen activator in cultured cells and in experimental animals

The tissue-type plasminogen activator (t-PA)-releasing action of synthetic dipeptides containing Gly, Ser or Pro was investigated. Among 10 dipeptides, Boc-L-Ser-L-Pro-OH and H-L-Ser-L-Pro-OH induced t-PA release in vitro, but the others were inactive. Since Boc-L-Ser-L-Pro-OH was more effective than H-L-Ser-L-Pro-OH, 7 related dipeptides with N-acylation were synthesized. Five of them enhanced the release of t-PA; N-stearoyl-L-Ser-L-Pro-OH (FK-5) had the greatest effect. Four compounds were further examined for activity to enhance the release of t-PA in rats. FK-5 produced a two-fold increase in fibrinolytic activity, and N-palmitoyl-L-Ser-L-Pro-OH (FK-4) also markedly enhanced the release of t-PA. Since FK-5 caused severe hemolysis, 7 analogues of FK-5 were synthesized. All of them enhanced the release of t-PA from melanoma (Bowes) cells. In rats, FK-5, N-stearoyl-D-Ser-L-Pro-OH (FK-8) and N-stearoyl-D-Ser-L-Pro-OEt (FK-10) enhanced the fibrinolytic activity two-fold. FK-5 and FK-8 also exhibited strong hemolytic activity, but FK-10 did not induce hemolysis. Therefore, FK-10 was examined in rabbits. After the injection of this compound, the fibrinolytic activity in the euglobulin fraction was markedly enhanced without accompanying hemolysis. Thus, FK-10 potently enhances fibrinolytic activity both in vitro and in vivo.

Age-dependent decrease in platelet aggregation in rats

The degree of platelet aggregation induced by ADP and collagen was examined in platelet-rich plasma from 7- to 90-week-old rats. The aggregation induced by ADP was unchanged at 90 weeks. Collagen-induced aggregation decreased remarkably at 60 and 90 weeks. Therefore, collagen-induced platelet activation is highly age-dependent, with rats of advanced age showing a lower response than younger rats.

Recombinant cyclic AMP response element binding protein (CREB) phosphorylated on Ser-133 is transcriptionally active upon its introduction into fibroblast nuclei

To date, it has not been possible to determine whether the single phosphorylation of the cyclic AMP response element binding factor (CREB) at Ser-133 is sufficient for the transcriptional activation by cAMP-mediated pathways. Previous in vivo studies investigating this point have relied upon transfection of cyclic AMP-dependent kinase (cAPK) or its activation by treatment of cells with cell-permeable cAMP analogs. However, as numerous cellular proteins, including CREB, are substrates for activated cAPK, the possibility remains that cAPK substrates other than CREB are required for the transcriptional activity of CRE-containing promoters. To further address this, we compared the activity of recombinant CREB phosphorylated on Ser-133 in both cell-free transcription assays and in vivo after introduction of the same preparations into fibroblasts by microinjection. The activity of phosphorylated CREB, nonphosphorylated CREB, and a mutant form of CREB, containing Ala substituted for Ser at position 133, was found to be nearly identical in cell-free in vitro transcription assays. In contrast, we found that only the phosphorylated CREB microinjected into fibroblasts resulted in the stimulation of expression of CRE-regulated genes. These results suggest that phosphorylation of CREB on Ser-133 directly stimulates its ability to transactivate gene expression in intact cells.

Signal transduction through the cAMP-dependent protein kinase

Temporal cellular events responsible for hormonal activation of responses mediated by the cAMP-dependent protein kinase (PKA) have been studied in living cells. By selectively perturbing molecular function of Gs, the catalytic subunit of PKA (C), or the nuclear factor CREB, in cells through microinjection of inhibitory agents specific for these molecules or activated forms of these molecules, we have obtained evidence for a requirement for the function of each of these molecules in the hormonal stimulation of cAMP-regulated genes. Moreover, by introducing fluorescently labeled PKA subunits into these cells as molecular tracers, or by immunofluorescence of C subunit, we have observed biological translocation of C subunit from the cytoplasm to the nucleus during transcriptional activation and a quenching of this by the inhibitor molecule, PKI. The implications of these cellular and molecular events in the signal transduction of hormonal responses are discussed.

Phosphorylated CREB binds specifically to the nuclear protein CBP

Cyclic AMP-regulated gene expression frequently involves a DNA element known as the cAMP-regulated enhancer (CRE). Many transcription factors bind to this element, including the protein CREB, which is activated as a result of phosphorylation by protein kinase A. This modification stimulates interaction with one or more of the general transcription factors or, alternatively, allows recruitment of a co-activator. Here we report that CREB phosphorylated by protein kinase A binds specifically to a nuclear protein of M(r) 265K which we term CBP (for CREB-binding protein). Fusion of a heterologous DNA-binding domain to the amino terminus of CBP enables the chimaeric protein to function as a protein kinase A-regulated transcriptional activator. We propose that CBP may participate in cAMP-regulated gene expression by interacting with the activated phosphorylated form of CREB.

Coupling of hormonal stimulation and transcription via the cyclic AMP-responsive factor CREB is rate limited by nuclear entry of protein kinase A

Cyclic AMP (cAMP) regulates a number of eukaryotic genes by mediating the protein kinase A (PKA)-dependent phosphorylation of the CREB transcription factor at Ser-133. In this study, we test the hypothesis that the stoichiometry and kinetics of CREB phosphorylation are determined by the liberation and subsequent translocation of PKA catalytic subunit (C subunit) into the nucleus. Using fluorescence imaging techniques, we observed that PKA was activated in a stimulus-dependent fashion that led to nuclear entry of C subunit over a 30-min period. The degree of CREB phosphorylation, assessed with antiserum specific for CREB phosphorylated at Ser-133, correlated with the amount of PKA liberated. The time course of phosphorylation closely paralleled the nuclear entry of the catalytic subunit. There was a linear relationship between the subsequent induction of the cAMP-responsive somatostatin gene and the degree of CREB phosphorylation, suggesting that each event--kinase activation, CREB phosphorylation, and transcriptional induction--was tightly coupled to the next. In contrast to other PKA-mediated cellular responses which are rapid and quantitative, the slow, incremental regulation of CREB activity by cAMP suggests that multifunctional kinases like PKA may coordinate cellular responses by dictating the kinetics and stoichiometry of phosphorylation for key substrates like CREB.

Assessment of protein kinase C isozymes by two-site enzyme immunoassay in human brains and changes in Alzheimer's disease

We assessed the amount of protein kinase C (PKC) in samples from postmortem normal human and Alzheimer's disease (AD) brains by a two-site enzyme immunoassay that quantitatively identified types alpha, beta, and gamma isozymes. In the normal human brain matter, type beta was the main type present, the majority of each isozyme of PKC being present in the membranous fraction of the brain tissues. In AD brains, the amount of type beta PKC was significantly reduced in the membranous fraction of the temporal cortical tissues. The amounts of types alpha and gamma in the membranous fraction and types alpha, beta, and gamma in the cytosolic fraction in AD brains were lower than in the control brains, but the difference was not significant. There was also a significant decrease in the levels of PKC in the membranous fraction of AD brains, as measured by radioactive phorbol ester binding. These results suggest that the type beta PKC isozyme is mainly present in the human temporal cortex and that reduced levels of type beta PKC in the membranous fraction may reflect a biochemical deficit related specifically to the pathogenesis of AD.

Alteration of human platelet protein kinase C with normal aging

Using a two-site enzyme immunoassay, we determined the content of type II protein kinase C (PKC) in human platelets from 24 donors of various ages without any neurological, hematological or malignant disorders. The content of type II PKC in the membranous fraction was positively correlated with aging. The content of PKC in the cytosolic fraction tended to decline with aging, but the correlation was not significant. The total amount of PKC also had no significant correlation with aging. Age-related changes in platelet protein content were not observed. These results suggested that the subcellular distribution of type II PKC in human platelets is altered with normal aging.

Effects of isoquinolinesulphonamide compounds on multidrug-resistant P388 cells

The effects of eight isoquinolinesulphonamide compounds on resistance to vinblastine in adriamycin-resistant mouse leukaemia cells (P388/ADR) which overexpress the relative molecular weight (M(r)) 140 kDa P-glycoprotein in the plasma membrane were investigated. N-[2-(Methylamino)ethyl]-5-isoquinolinesulphonamide (H-8) and N-(2-aminoethyl)-5-isoquinolinesulphonamide (H-9) did not reverse vinblastine resistance. N-[2-[N-[3-(4-Chlorophenyl)-2-propenyl]amino] ethyl]-5-isoquinolinesulphonamide (H-86) and N-[2-[N-[3-(4-chlorophenyl)-1-methyl-2-propenyl] amino]ethyl]-5-isoquinolinesulphonamide (H-87) caused accumulation of intracellular vinblastine and inhibition of vinblastine efflux from the cells and reversed the resistance. Addition of an aminoethyl group to the nitrogen atom of the sulphonamide group (W-66) or a formyl group at the terminal amino group (H-85) of H-86 reduced those activities. Conversion of the chlorophenyl group of H-87 to pyridinyl (H-31) or furanyl (H-34) markedly decreased activities against the drug resistance. The activity against vinblastine accumulation closely correlated with the apparent partition coefficient of compounds. These compounds dose-dependently inhibited photoaffinity labelling of a photosensitive analogue of vinblastine, N-(p-azido-(3-[125I)salicyl)-N'-beta-aminoethyl-vindesine ([125I]NASV), and there was a good correlation between inhibition of [125I]NASV-photolabelling and hydrophobicity. Although these isoquinolinesulphonamides inhibited protein kinase A with different magnitudes, this activity did not correlate with the effect on the drug resistance. These results indicate that isoquinolinesulphonamide compounds with a hydrophobic group interact with antitumour drugs on P-glycoprotein and reverse multidrug resistance without involvement of their activity on protein kinase A.