Autophosphorylation reversibly regulates the Ca2+/calmodulin-dependence of Ca2+/calmodulin-dependent protein kinase II

Ca2+/calmodulin-dependent protein kinase II contains two subunits, alpha (Mr 50,000) and beta (Mr 60,000/58,000), both of which undergo Ca2+/calmodulin-dependent autophosphorylation. In the present study, we have studied the mechanism of this autophosphorylation reaction and its effect on the activity of the enzyme. Both subunits are autophosphorylated through an intramolecular mechanism. Using synapsin I as substrate, Ca2+/calmodulin-dependent protein kinase II, in its unphosphorylated form, was totally dependent on Ca2+ and calmodulin for its activity. Preincubation of the enzyme with Ca2+, calmodulin, and ATP, under conditions where autophosphorylation of both subunits occurred, converted the enzyme to one that was only partially dependent on Ca2+ and calmodulin for its activity. No change in the total activity, measured in the presence of Ca2+ and calmodulin, was observed. The nonhydrolyzable ATP analog adenosine 5'-[beta, gamma-imido] triphosphate did not substitute for ATP in the preincubation. Moreover, dephosphorylation of autophosphorylated Ca2+/calmodulin-dependent protein kinase II with protein phosphatase 2A resulted in an enzyme that was again totally dependent on Ca2+ and calmodulin for its activity. We propose that autophosphorylation and dephosphorylation reversibly regulate the Ca2+ and calmodulin requirement of Ca2+/calmodulin-dependent protein kinase II.

Intracellular drug concentrations and transporters: measurement, modeling, and implications for the liver

Intracellular concentrations of drugs and metabolites are often important determinants of efficacy, toxicity, and drug interactions. Hepatic drug distribution can be affected by many factors, including physicochemical properties, uptake/efflux transporters, protein binding, organelle sequestration, and metabolism. This white paper highlights determinants of hepatocyte drug/metabolite concentrations and provides an update on model systems, methods, and modeling/simulation approaches used to quantitatively assess hepatocellular concentrations of molecules. The critical scientific gaps and future research directions in this field are discussed.

Functional modulation of brain sodium channels by cAMP-dependent phosphorylation

Voltage-gated Na+ channels, which are responsible for the generation of action potentials in brain, are phosphorylated by cAMP-dependent protein kinase in vitro and in intact neurons. Phosphorylation by cAMP-dependent protein kinase reduces peak Na+ currents 40%--50% in membrane patches excised from rat brain neurons or from CHO cells expressing type IIA Na+ channels. Inhibition of basal cAMP-dependent protein kinase activity by transfection with a plasmid encoding a dominant negative mutant regulatory subunit increases Na+ channel number and activity, indicating that even the basal level of kinase activity is sufficient to reduce Na+ channel activity significantly. Na+ currents in membrane patches from kinase-deficient cells were reduced up to 80% by phosphorylation by cAMP-dependent protein kinase. These effects could be blocked by a specific peptide inhibitor of cAMP-dependent protein kinase and reversed by phosphoprotein phosphatases. Convergent modulation of brain Na+ channels by neurotransmitters acting through the cAMP and protein kinase C signaling pathways may result in associative regulation of electrical activity by different synaptic inputs.

Estimation of in vivo human brain-to-skull conductivity ratio from simultaneous extra- and intra-cranial electrical potential recordings

OBJECTIVE

The present study aims to accurately estimate the in vivo brain-to-skull conductivity ratio by means of cortical imaging technique. Simultaneous extra- and intra-cranial potential recordings induced by subdural current stimulation were analyzed to get the estimation.

METHODS

The effective brain-to-skull conductivity ratio was estimated in vivo for 5 epilepsy patients. The estimation was performed using multi-channel simultaneously recorded scalp and cortical electrical potentials during subdural electrical stimulation. The cortical imaging technique was used to compute the inverse cortical potential distribution from the scalp recorded potentials using a 3-shell head volume conductor model. The brain-to-skull conductivity ratio, which leads to the most consistent cortical potential estimates with respect to the direct intra-cranial measurements, is considered to be the effective brain-to-skull conductivity ratio.

RESULTS

The present estimation provided consistent results in 5 human subjects studied. The in vivo effective brain-to-skull conductivity ratio ranged from 18 to 34 in the 5 epilepsy patients.

CONCLUSIONS

The effective brain-to-skull conductivity ratio can be estimated from simultaneous intra- and extra-cranial potential recordings and the averaged value/standard deviation is 25+/-7.

SIGNIFICANCE

The present results provide important experimental data on the brain-to-skull conductivity ratio, which is of significance for accurate brain source localization using piece-wise homogeneous head models.

Biochemical evidence for a complex involving dihydropyridine receptor and ryanodine receptor in triad junctions of skeletal muscle

Membrane vesicles enriched in both ryanodine receptor and dihydropyridine receptor were obtained from rabbit skeletal muscle and solubilized with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate. Analysis of the sedimentation behavior of the solubilized proteins showed the existence of a population of alpha 1 subunits of the dihydropyridine receptor which cosedimented with the ryanodine receptor. Solubilized proteins were immunoprecipitated with antibodies directed against either the ryanodine receptor or the alpha 1, alpha 2, or beta subunits of the dihydropyridine receptor. Immunoprecipitated proteins were identified by Western blot analysis and by specific labeling with [3H]ryanodine or [3H]PN200-110. Immunoprecipitation of the solubilized proteins with antibodies directed against the dihydropyridine receptor led to the coimmunoprecipitation of the ryanodine receptor. Conversely, immunoprecipitation with antibodies directed against the ryanodine receptor led to an immune complex containing both receptors, but these antibodies were unable to precipitate purified dihydropyridine receptor. These results demonstrate that ryanodine receptor and dihydropyridine receptor are present in the triad membrane preparation in a complex which may play an important role in excitation-contraction coupling.

A multifunctional calmodulin-dependent protein kinase. Similarities between skeletal muscle glycogen synthase kinase and a brain synapsin I kinase

Calmodulin-dependent glycogen synthase kinase isolated from skeletal muscle and synapsin I kinase II isolated from brain have several properties that are very similar. These properties include: substrate and site-specificities, immunological cross-reactivity, and phosphopeptide maps following limited proteolysis. Both enzymes phosphorylate a wide variety of substrate proteins. The two kinases may represent different isozymes of a multifunctional calmodulin-dependent protein kinase that mediates many of the actions of Ca2+ in various tissues. Therefore, we propose the name 'calmodulin-dependent multi-protein kinase' for this broad specificity enzyme.

LC-MS/MS-based quantification of clinically relevant intestinal uptake and efflux transporter proteins

Multidrug transporter proteins are crucial determinants in the pharmacokinetics of many drugs. To evaluate their impact on intestinal drug absorption, we developed and validated quantification methods for 10 uptake transporters (OATP1A2, OATP2B1, PEPT1, ASBT, OCT1, OCT3) and efflux transporters (ABCB1, ABCC2, ABCC3, ABCG2) that have been reported to be expressed and to be of clinical relevance in the human intestine. Quantification was performed by targeted liquid chromatography with tandem mass spectrometry (LC-MS/MS)-based quantification of proteospecific peptides after tryptic digestion using stable isotope labeled internal standard peptides. The chromatography of the respective peptides was performed by gradient elution using a reversed phase (C18) column (Kinetex(®), 100 × 3.0 mm, 2.6 μm) and 0.1% formic acid (FA) and acetonitrile with 0.1% FA as mobile phases at a flow rate of 0.5 ml/min. The MS/MS detection was done in the positive multiple reaction monitoring (MRM) mode by monitoring in each case three mass transitions for the transporter-derived peptides and the internal standard peptides. The assays were validated with respect to specificity, linearity (0.1-25 nM), within-day and between-day accuracy and precision as well as stability according to current bioanalytical guidelines. Finally, the developed methods were used to determine the transporter protein content in human intestinal tissue (jejunum and ileum). The methods were shown to possess sufficient specificity, sensitivity, accuracy, precision and stability to measure transporter proteins in the human intestine.

Surface-enrichment with hydroxyapatite nanoparticles in stereolithography-fabricated composite polymer scaffolds promotes bone repair

Fabrication of composite scaffolds using stereolithography (SLA) for bone tissue engineering has shown great promises. However, in order to trigger effective bone formation and implant integration, exogenous growth factors are commonly combined to scaffold materials. In this study, we fabricated biodegradable composite scaffolds using SLA and endowed them with osteopromotive properties in the absence of biologics. First we prepared photo-crosslinkable poly(trimethylene carbonate) (PTMC) resins containing 20 and 40wt% of hydroxyapatite (HA) nanoparticles and fabricated scaffolds with controlled macro-architecture. Then, we conducted experiments to investigate how the incorporation of HA in photo-crosslinked PTMC matrices improved human bone marrow stem cells osteogenic differentiation in vitro and kinetic of bone healing in vivo. We observed that bone regeneration was significantly improved using composite scaffolds containing as low as 20wt% of HA, along with difference in terms of osteogenesis and degree of implant osseointegration. Further investigations revealed that SLA process was responsible for the formation of a rich microscale layer of HA corralling scaffolds. To summarize, this work is of substantial importance as it shows how the fabrication of hierarchical biomaterials via surface-enrichment of functional HA nanoparticles in composite polymer stereolithographic structures could impact in vitro and in vivo osteogenesis.

STATEMENT OF SIGNIFICANCE

This study reports for the first time the enhance osteopromotion of composite biomaterials, with controlled macro-architecture and microscale distribution of hydroxyapatite particles, manufactured by stereolithography. In this process, the hydroxyapatite particles are not only embedded into an erodible polymer matrix, as reported so far in the literature, but concentrated at the surface of the structures. This leads to robust in vivo bone formation at low concentration of hydroxyapatite. The reported 3D self-corralling composite architecture provides significant opportunities to develop functional biomaterials for bone repair and tissue engineering.

Disruption of nNOS-PSD95 protein-protein interaction inhibits acute thermal hyperalgesia and chronic mechanical allodynia in rodents

BACKGROUND AND PURPOSE

Post-synaptic density protein 95 (PSD95) contains three PSD95/Dosophilia disc large/ZO-1 homology domains and links neuronal nitric oxide synthase (nNOS) with the N-methyl-D-aspartic acid (NMDA) receptor. This report assesses the effects of disruption of the protein-protein interaction between nNOS and PSD95 on pain sensitivity in rodent models of hyperalgesia and neuropathic pain.

EXPERIMENTAL APPROACH

We generated two molecules that interfered with the nNOS-PSD95 interaction: IC87201, a small molecule inhibitor; and tat-nNOS (residues 1-299), a cell permeable fusion protein containing the PSD95 binding domain of nNOS. We then characterized these inhibitors using in vitro and in vivo models of acute hyperalgesia and chronic allodynia, both of which are thought to require nNOS activation.

KEY RESULTS

IC87201 and tat-nNOS (1-299) inhibited the in vitro binding of nNOS with PSD95, without inhibiting nNOS catalytic activity. Both inhibitors also blocked NMDA-induced 3',5'-cyclic guanosine monophosphate (cGMP) production in primary hippocampal cultures. Intrathecal administration of either inhibitor potently reversed NMDA-induced thermal hyperalgesia in mice. At anti-hyperalgesic doses, there was no effect on acute pain thresholds or motor coordination. Intrathecal administration of IC87201 and tat-nNOS also reversed mechanical allodynia induced by chronic constriction of the sciatic nerve.

CONCLUSIONS AND IMPLICATIONS

nNOS-PSD95 interaction is important in maintaining hypersensitivity in acute and chronic pain. Disruption of the nNOS-PSD95 interaction provides a novel approach to obtain selective anti-hyperalgesic compounds.

Toll-like receptor 2 costimulation potentiates the antitumor efficacy of CAR T Cells

Chimeric antigen receptor (CAR) T-cell immunotherapies have shown unprecedented success in treating leukemia but limited clinical efficacy in solid tumors. Here, we generated 1928zT2 and m28zT2, targeting CD19 and mesothelin, respectively, by introducing the Toll/interleukin-1 receptor domain of Toll-like receptor 2 (TLR2) to 1928z and m28z. T cells expressing 1928zT2 or m28zT2 showed improved expansion, persistency and effector function against CD19⁺ leukemia or mesothelin⁺ solid tumors respectively in vitro and in vivo. In a patient with relapsed B-cell acute lymphoblastic leukemia, a single dose of 5 × 10⁴/kg 1928zT2 T cells resulted in robust expansion and leukemia eradication and led to complete remission. Hence, our results demonstrate that TLR2 signaling can contribute to the efficacy of CAR T cells. Further clinical trials are warranted to establish the safety and efficacy of this approach.

Ca2+/calmodulin-dependent protein kinase II: identification of autophosphorylation sites responsible for generation of Ca2+/calmodulin-independence

Ca2+/calmodulin-dependent protein kinase II contains two types of subunit, alpha (Mr 50,000) and beta (Mr 60,000/58,000), both of which undergo Ca2+/calmodulin-dependent autophosphorylation. Autophosphorylation is known to convert the enzyme to a Ca2+/calmodulin-independent form. In the present study, we have characterized the autophosphorylation sites on rat forebrain Ca2+/calmodulin-dependent protein kinase II that are most likely to be responsible for the generation of Ca2+/calmodulin-independence. Under conditions (0 degree C, low concentrations of ATP) sufficient to generate close to maximal Ca2+/calmodulin-independence, only a few of the phosphorylatable sites on the enzyme became phosphorylated. These autophosphorylation sites were examined by phospho amino acid analysis, two-dimensional thermolytic phosphopeptide mapping, and high-performance liquid chromatography. The time course of phosphorylation of threonine in both alpha and beta subunits was similar to the time course of the generation of Ca2+/calmodulin-independence. Moreover, the time course of phosphorylation of one set of peptides, referred to as peptide 1/1', present in both alpha and beta subunits was similar to the time course of the generation of Ca2+/calmodulin-independence. Threonine was the only amino acid phosphorylated in peptide 1/1'. An additional peptide, referred to as peptide 2, was phosphorylated in the beta subunit. The time course of phosphorylation of peptide 2, which also contained only phosphothreonine, did not parallel the time course of the generation of Ca2+/calmodulin-independence. It is likely that the phosphorylation of a threonine residue on peptide 1/1' is responsible for the generation of Ca2+/calmodulin-independence of Ca2+/calmodulin-dependent protein kinase II.

A novel fish cell line derived from the brain of Chinese perch Siniperca chuatsi: development and characterization

In this study, a continuous cell line (named as CPB) was established from Siniperca chuatsi brain and has been subcultured >140 times. CPB cell line predominantly consisted of fibroblast-like cells that could grow better in Leibovitz's L-15 supplemented with 10% foetal bovine serum at 28° C. Polymerase chain reaction amplification of 18s recombinant (r)RNA confirmed the origin of this cell line from S. chuatsi. The CPB cell line was cryopreserved at different passage levels and revived successfully with 80-90% survival. The cell line was further characterized by chromosome number and transfection. The CPB cells were highly susceptible to infectious spleen and kidney necrosis virus (ISKNV) with a titre of 6·58-6·62 log TCID50 ml(-1) and numerous ISKNV particles were observed in the cytoplasm by transmission electron microscopy. At the same time, ISKNV infection was confirmed by reverse transcriptase polymerase chain reaction, immunodot blot and individual challenge experiments. The development and characterization of a new brain cell line from S. chuatsi were described in this study and it could be used as an in vitro tool for propagation of ISKNV and gene expression studies.

The mitotic checkpoint kinase NEK2A regulates kinetochore microtubule attachment stability

Loss or gain of whole chromosome, the form of chromosome instability commonly associated with cancers is thought to arise from aberrant chromosome segregation during cell division. Chromosome segregation in mitosis is orchestrated by the interaction of kinetochores with spindle microtubules. Our studies show that NEK2A is a kinetochore-associated protein kinase essential for faithful chromosome segregation. However, it was unclear how NEK2A ensures accurate chromosome segregation in mitosis. Here we show that NEK2A-mediated Hec1 (highly expressed in cancer) phosphorylation is essential for faithful kinetochore microtubule attachments in mitosis. Using phospho-specific antibody, our studies show that NEK2A phosphorylates Hec1 at Ser165 during mitosis. Although such phosphorylation is not required for assembly of Hec1 to the kinetochore, expression of non-phosphorylatable mutant Hec1(S165) perturbed chromosome congression and resulted in a dramatic increase in microtubule attachment errors, including syntelic and monotelic attachments. Our in vitro reconstitution experiment demonstrated that Hec1 binds to microtubule in low affinity and phosphorylation by NEK2A, which prevents aberrant kinetochore-microtubule connections in vivo, increases the affinity of the Ndc80 complex for microtubules in vitro. Thus, our studies illustrate a novel regulatory mechanism in which NEK2A kinase operates a faithful chromosome attachment to spindle microtubule, which prevents chromosome instability during cell division.

AKAP79 inhibits calcineurin through a site distinct from the immunophilin-binding region

Targeting of protein kinases and phosphatases provides additional specificity to substrate selectivity in cellular signaling. In the case of the Ca2+/calmodulin-dependent protein phosphatase calcineurin, AKAP79 has been shown to bind calcineurin and inhibit its activity in vitro (Coghlan, V., Perrino, B. A., Howard, M., Langeberg, L. K., Hicks, J. B., Gallatin, W. M., and Scott, J. D. (1995) Science 267, 108-111). In the present study, we characterized the binding regions on calcineurin A (CnA) and AKAP79 that are important for this interaction. Residues 30-98 and 311-336 on CnA, and residues 108-280 on AKAP79 were found to be important for binding. The binding of CnA by AKAP79 does not require the calcineurin B subunit, and occurs in a region distinct from where the immunosuppressant-immunophilin complex bind. AKAP79 also bound to CnA in cells transfected with AKAP79 and CnA. To determine the function of AKAP79-calcineurin interaction in intact cells, we measured the dephosphorylation and subsequent activation of NFAT, a transcription factor that is a substrate for calcineurin. Overexpression of AKAP79 inhibited NFAT dephosphorylation, resulting in a decrease in NFAT activation. These results demonstrated that AKAP79 can bind to and inhibit calcineurin activity in vivo, suggesting a physiological role for AKAP79-calcineurin interaction in NFAT-mediated signaling.

Ischaemia is linked to inflammation and induction of angiogenesis in pancreatic islets

Beta-cell replacement is the only way to restore euglycaemia in patients with type-1 diabetes. Pancreatic tissue, processed for subsequent clinical islet transplantation, is exposed to ischaemia causing injury and death in a large number of islets before and after transplantation. In this review we summarize what is known on the sources of environmental stress for pancreatic islets, such as insufficient oxygen supply during pancreas procurement and in culture prior to intraportal transplantation, nutritional and oxygen deprivation during the isolation process, and the consequences of hyperglycaemia. An increasingly recognized role in the modulation of beta-cell function and these environmental stress factors plays the vascular network of the pancreatic islets. Islet revascularization by angiogenesis is relevant for the survival of the graft subsequent to transplantation. Potential strategies offered by therapeutic induction of revascularization to ameliorate the detrimental impact of these factors on the quality of islet transplants are discussed.

Relationship between levels of secreted phospholipase A₂ groups IIA and X in the airways and asthma severity

Background Secreted phospholipase A(2) (sPLA(2) ) may be important mediators of asthma, but the specific sPLA(2) s involved in asthma are not known. Objective To evaluate sPLA(2) group IIA, V, and X proteins (sPLA(2) -IIA, sPLA(2) -V, and sPLA(2) -X) in bronchoalveolar lavage (BAL) fluid, BAL cells, and airway epithelial cells of subjects with and without asthma, and examine the relationship between the levels of specific sPLA(2) enzymes and airway inflammation, asthma severity, and lung function. Methods The expression of sPLA(2) -IIA, sPLA(2) -V, and sPLA(2) -X in BAL cells and epithelial brushings was assessed by qPCR. The levels of these sPLA(2) proteins and sPLA(2) activity with and without group II and group X-specific inhibitors were measured in BAL fluid from 18 controls and 39 asthmatics. Results The airway epithelium expressed sPLA(2) -X at higher levels than either sPLA(2) -IIA or sPLA(2) -V, whereas BAL cells expressed sPLA(2) -IIA and sPLA(2) -X at similar levels. The majority of sPLA(2) activity in BAL fluid was attributed to either sPLA(2) -IIA or sPLA(2) -X. After 10-fold concentration of BAL fluid, the levels of sPLA(2) -X normalized to total protein were increased in asthma and were associated with lung function, the concentration of induced sputum neutrophils, and prostaglandin E(2) . The levels of sPLA(2) -IIA were elevated in asthma when normalized to total protein, but were not related to lung function, markers of airway inflammation or eicosanoid formation. Conclusions and Clinical Relevance These data indicate that sPLA(2) -IIA and sPLA(2) -X are the major sPLA(2) s in human airways, and suggest a link between the levels of sPLA(2) -X in the airways and several features of asthma.

Protein phosphorylation in cultured endothelial cells

We have investigated the protein phosphorylation systems present in cultured bovine aortic and pulmonary artery endothelial cells. The cells contain cyclic AMP-dependent protein kinase, three calcium/calmodulin-dependent protein kinases, protein kinase C, and at least one tyrosine kinase. No cyclic GMP-dependent protein kinase activity was found. The cells also contained numerous substrates for cyclic AMP-dependent protein kinase and protein kinase C. Fewer substrates were found for the calcium/calmodulin-dependent protein kinases. There was little difference between either protein kinase activities or substrates when pulmonary artery endothelium was compared to aortic endothelium grown under similar culture conditions. It is likely that these various protein kinases and their respective substrate proteins are involved in mediating several of the actions of the hormones and drugs which affect the vascular endothelium.

Pulsatile flow simulation in arterial vascular segments with intravascular ultrasound images

Previous studies have indicated a correlation between local variation in wall shear stress in arterial blood flow and atheroma development. The purpose of this study was to analyze the hemodynamics in vascular segments from morphologically realistic three-dimensional (3D) reconstruction, and to compare the computed wall shear stress in a compliant vascular segment model and the corresponding rigid walled model. Cross-sectional images of the segments of femoral and carotid arteries in five Yucatan miniswine were obtained using intravascular ultrasound (IVUS) imaging and the segment geometry was reconstructed at different times in the cardiac cycle. The actual measured wall motion from the reconstruction was employed to specify the moving boundaries for simulation of physiological distensibility. Velocity profiles and wall shear stress were computed using unsteady computational fluid dynamics analysis. The computed results revealed that the maximum wall shear stress in the compliant model was approximately 4-17 percent less than that in the rigid model if the wall motion is larger than 10 percent. Our analysis demonstrates that inaccuracies due to inflow velocity profile can be minimized by the extension of the model upstream. The phase angle between the diameter change and wall shear is affected by the local changes in geometry of the arteries. These simulations can be potentially used to analyze the effect of regional wall motion changes in the presence of atherosclerotic lesions on the local fluid dynamics and to correlate the same with subsequent growth of the lesions.

Cell-specific localization of the alpha-subunit of calcium/calmodulin-dependent protein kinase II in Purkinje cells in rodent cerebellum

Brain calcium/calmodulin-dependent protein kinase type II, a multimeric 600-650 kDa enzyme composed of alpha- (50 kDa) and beta/beta' (60 and 58 kDa) subunits, may be formed by alpha- and beta-subunits combining in variable proportions in different types of neurons. This study presents evidence, using cerebella from mutant mice, that the alpha-subunit displays a restricted localization in the rodent cerebellum, being detectable only in Purkinje cells. Immunocytochemical analysis of normal rat cerebellum with an antibody selective for the alpha-subunit confirmed that this subunit was detectable only in Purkinje cells. In contrast, the beta/beta'-subunits appeared to be present in all types of cerebellar mutants examined. These results indicate that different cells of the cerebellum express distinct isozymic forms of the multifunctional calcium/calmodulin-dependent protein kinase type II. It appears that Purkinje cells primarily contain an isoenzyme formed by both alpha- and beta/beta'-subunits, and that non-Purkinje cells contain an isoenzyme formed primarily by beta/beta'-subunits.

Conjugated linoleic acid improves airway hyper-reactivity in overweight mild asthmatics

BACKGROUND

Conjugated linoleic acids (CLA) are naturally occurring fatty acids that have multiple biological properties including the regulation of metabolic, proliferative and immune processes.

OBJECTIVE

The aim of this study was to investigate the efficacy and safety of CLA as a dietary supplement in mild asthma.

METHODS

This was a prospective, randomized, double-blind, placebo-controlled study. Twenty-eight adult subjects (aged 19-40 years) with mild asthma (FEV(1)>70% predicted) were randomized to CLA 4.5 g/day or placebo for 12 weeks in addition to usual treatment. On average, subjects were overweight with a mean body mass index (BMI) of 27.9 kg/m(2).

RESULTS

Subjects in the CLA group had a significant improvement in airway hyperresponsiveness (AHR) at week 12 compared with week 0 [PC(20) 6.6 (2.1) mg/mL vs. 2.2 (0.7) mg/mL; P<0.05]. The CLA group had a significant reduction in weight and BMI compared with placebo and this was associated with a reduction in leptin/adiponectin ratio. There were no differences in systemic cytokine levels, induced sputum cell counts, quality-of-life scores or adverse events.

CONCLUSIONS

CLA treatment as an adjunct to usual care in overweight mild asthmatics was well tolerated and was associated with improvements in AHR and BMI.

Localization of the A kinase anchoring protein AKAP79 in the human hippocampus

The phosphorylation state of the proteins, regulated by phosphatases and kinases, plays an important role in signal transduction and long-term changes in neuronal excitability. In neurons, cAMP-dependent protein kinase (PKA), protein kinase C (PKC) and calcineurin (CN) are attached to a scaffold protein, A kinase anchoring protein (AKAP), thought to anchor these three enzymes to specific sites of action. However, the localization of AKAP, and the predicted sites of linked phosphatase and kinase activities, are still unknown at the fine structural level. In the present study, we investigated the distribution of AKAP79 in the hippocampus from postmortem human brains and lobectomy samples from patients with intractable epilepsy, using preembedding immunoperoxidase and immunogold histochemical methods. AKAP79 was found in the CA1, presubicular and subicular regions, mostly in pyramidal cell dendrites, whereas pyramidal cells in the CA3, CA2 regions and dentate granule cells were negative both in postmortem and in surgical samples. In some epileptic cases, the dentate molecular layer and hilar interneurons also became immunoreactive. At the subcellular level, AKAP79 immunoreactivity was present in postsynaptic profiles near, but not attached to, the postsynaptic density of asymmetrical (presumed excitatory) synapses. We conclude that the spatial selectivity for the action of certain kinases and phosphatases regulating various ligand- and voltage-gated channels may be ensured by the selective presence of their anchoring protein, AKAP79, at the majority of glutamatergic synapses in the CA1, but not in the CA2/CA3 regions, suggesting profound differences in signal transduction and long-term synaptic plasticity between these regions of the human hippocampus.

Effects of cyclic AMP on development and secondary metabolites of Monascus ruber M-7

AIM

To study effects of cyclic adenosine monophosphate (cAMP) on development and secondary metabolites of Monascus ruber M-7.

METHODS AND RESULTS

Plate culture, liquid-state fermentation (LSF) and solid-state fermentation (SSF) were used to evaluate effects of cAMP on colonial growth, spore formation and polyketide production of Strain M-7. The results revealed that the variation trends of colonial sizes, numbers of sexual spores and red pigment contents of M-7 were in a dose-dependent manner. And generally they increased and decreased with cAMP concentrations in the ranges of low cAMP concentrations and high cAMP concentrations, respectively. But the variation trends of numbers of asexual spores and citrinin production in both LSF and SSF were opposite to those of colonial sizes, sexual sporulation and red pigment.

CONCLUSIONS

The regulation of cAMP on development and secondary metabolites in Strain M-7 was in a dose-dependent pattern. And red pigment might convert to citrinin under changing cAMP concentrations.

SIGNIFICANCE AND IMPACT OF THE STUDY

The effects of cAMP on Strain M-7 in SSF give a new clue to enhance beneficial polyketides and reduce citrinin produced by M. ruber.