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91.
Heterogeneity of ATP-sensitive K+ Channels in Cardiac Myocytes: ENRICHMENT AT THE INTERCALATED DISK*
Miyoun Hong Li Bao Eirini Kefaloyianni Esperanza Agullo-Pascual Halina Chkourko Monique Foster Eylem Taskin Marine Zhandre Dylan A. Reid Eli Rothenberg Mario Delmar William A. Coetzee 《The Journal of biological chemistry》2012,287(49):41258-41267
Ventricular ATP-sensitive potassium (KATP) channels link intracellular energy metabolism to membrane excitability and contractility. Our recent proteomics experiments identified plakoglobin and plakophilin-2 (PKP2) as putative KATP channel-associated proteins. We investigated whether the association of KATP channel subunits with junctional proteins translates to heterogeneous subcellular distribution within a cardiac myocyte. Co-immunoprecipitation experiments confirmed physical interaction between KATP channels and PKP2 and plakoglobin in rat heart. Immunolocalization experiments demonstrated that KATP channel subunits (Kir6.2 and SUR2A) are expressed at a higher density at the intercalated disk in mouse and rat hearts, where they co-localized with PKP2 and plakoglobin. Super-resolution microscopy demonstrate that KATP channels are clustered within nanometer distances from junctional proteins. The local KATP channel density, recorded in excised inside-out patches, was larger at the cell end when compared with local currents recorded from the cell center. The KATP channel unitary conductance, block by MgATP and activation by MgADP, did not differ between these two locations. Whole cell KATP channel current density (activated by metabolic inhibition) was ∼40% smaller in myocytes from mice haploinsufficient for PKP2. Experiments with excised patches demonstrated that the regional heterogeneity of KATP channels was absent in the PKP2 deficient mice, but the KATP channel unitary conductance and nucleotide sensitivities remained unaltered. Our data demonstrate heterogeneity of KATP channel distribution within a cardiac myocyte. The higher KATP channel density at the intercalated disk implies a possible role at the intercellular junctions during cardiac ischemia. 相似文献
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Phospholipases A2 (PLA2) catalyse the cleavage of fatty acids esterified at the sn-2 position of glycerophospholipids. In acute lung injury-acute respiratory distress syndrome (ALI-ARDS) several distinct isoenzymes appear in lung cells and fluid. Some are capable to trigger molecular events leading to enhanced inflammation and lung damage and others have a role in lung surfactant recycling preserving lung function: Secreted forms (groups sPLA2-IIA, -V, -X) can directly hydrolyze surfactant phospholipids. Cytosolic PLA2 (cPLA2-IVA) requiring Ca2+ has a preference for arachidonate, the precursor of eicosanoids which participate in the inflammatory response in the lung. Ca2+-independent intracellular PLA2s (iPLA2) take part in surfactant phospholipids turnover within alveolar cells. Acidic Ca2+-independent PLA2 (aiPLA2), of lysosomal origin, has additionally antioxidant properties, (peroxiredoxin VI activity), and participates in the formation of dipalmitoyl-phosphatidylcholine in lung surfactant. PAF-AH degrades PAF, a potent mediator of inflammation, and oxidatively fragmented phospholipids but also leads to toxic metabolites. Therefore, the regulation of PLA2 isoforms could be a valuable approach for ARDS treatment. 相似文献
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Vassilakos N Bem F Tzima A Barker H Reavy B Karanastasi E Robinson DJ 《Transgenic research》2008,17(5):929-941
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Franc Llorens Katrin Thüne Waqas Tahir Eirini Kanata Daniela Diaz-Lucena Konstantinos Xanthopoulos Eleni Kovatsi Catharina Pleschka Paula Garcia-Esparcia Matthias Schmitz Duru Ozbay Susana Correia Ângela Correia Ira Milosevic Olivier Andréoletti Natalia Fernández-Borges Ina M. Vorberg Markus Glatzel Theodoros Sklaviadis Juan Maria Torres Susanne Krasemann Raquel Sánchez-Valle Isidro Ferrer Inga Zerr 《Molecular neurodegeneration》2017,12(1):83
Background
YKL-40 (also known as Chitinase 3-like 1) is a glycoprotein produced by inflammatory, cancer and stem cells. Its physiological role is not completely understood but YKL-40 is elevated in the brain and cerebrospinal fluid (CSF) in several neurological and neurodegenerative diseases associated with inflammatory processes. Yet the precise characterization of YKL-40 in dementia cases is missing.Methods
In the present study, we comparatively analysed YKL-40 levels in the brain and CSF samples from neurodegenerative dementias of different aetiologies characterized by the presence of cortical pathology and disease-specific neuroinflammatory signatures.Results
YKL-40 was normally expressed in fibrillar astrocytes in the white matter. Additionally YKL-40 was highly and widely expressed in reactive protoplasmic cortical and perivascular astrocytes, and fibrillar astrocytes in sporadic Creutzfeldt-Jakob disease (sCJD). Elevated YKL-40 levels were also detected in Alzheimer’s disease (AD) but not in dementia with Lewy bodies (DLB). In AD, YKL-40-positive astrocytes were commonly found in clusters, often around β-amyloid plaques, and surrounding vessels with β-amyloid angiopathy; they were also distributed randomly in the cerebral cortex and white matter. YKL-40 overexpression appeared as a pre-clinical event as demonstrated in experimental models of prion diseases and AD pathology.CSF YKL-40 levels were measured in a cohort of 288 individuals, including neurological controls (NC) and patients diagnosed with different types of dementia. Compared to NC, increased YKL-40 levels were detected in sCJD (p < 0.001, AUC = 0.92) and AD (p < 0.001, AUC = 0.77) but not in vascular dementia (VaD) (p > 0.05, AUC = 0.71) or in DLB/Parkinson’s disease dementia (PDD) (p > 0.05, AUC = 0.70). Further, two independent patient cohorts were used to validate the increased CSF YKL-40 levels in sCJD. Additionally, increased YKL-40 levels were found in genetic prion diseases associated with the PRNP-D178N (Fatal Familial Insomnia) and PRNP-E200K mutations.Conclusions
Our results unequivocally demonstrate that in neurodegenerative dementias, YKL-40 is a disease-specific marker of neuroinflammation showing its highest levels in prion diseases. Therefore, YKL-40 quantification might have a potential for application in the evaluation of therapeutic intervention in dementias with a neuroinflammatory component.97.
Pim Cuijpers Eirini Karyotaki Mirjam Reijnders Marianna Purgato Corrado Barbui 《World psychiatry》2018,17(1):90-101
Most psychotherapies for depression have been developed in high‐income Western countries of North America, Europe and Australia. A growing number of randomized trials have examined the effects of these treatments in non‐Western countries. We conducted a meta‐analysis of these studies to examine whether these psychotherapies are effective and to compare their effects between studies from Western and non‐Western countries. We conducted systematic searches in bibliographical databases and included 253 randomized controlled trials, of which 32 were conducted in non‐Western countries. The effects of psychotherapies in non‐Western countries were large (g=1.10; 95% CI: 0.91‐1.30), with high heterogeneity (I2=90; 95% CI: 87‐92). After adjustment for publication bias, the effect size dropped to g=0.73 (95% CI: 0.51‐0.96). Subgroup analyses did not indicate that adaptation to the local situation was associated with the effect size. Comparisons with the studies in Western countries showed that the effects of the therapies were significantly larger in non‐Western countries, also after adjusting for characteristics of the participants, the treatments and the studies. These larger effect sizes in non‐Western countries may reflect true differences indicating that therapies are indeed more effective; or may be explained by the care‐as‐usual control conditions in non‐Western countries, often indicating that no care was available; or may be the result of the relative low quality of many trials in the field. This study suggests that psychotherapies that were developed in Western countries may or may not be more effective in non‐Western countries, but they are probably no less effective and can therefore also be used in these latter countries. 相似文献
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Macaques infected with a CCR5-tropic simian/human immunodeficiency virus (SHIV) develop broadly reactive anti-HIV neutralizing antibodies
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Kraft Z Derby NR McCaffrey RA Niec R Blay WM Haigwood NL Moysi E Saunders CJ Wrin T Petropoulos CJ McElrath MJ Stamatatos L 《Journal of virology》2007,81(12):6402-6411
The development of anti-human immunodeficiency virus (anti-HIV) neutralizing antibodies and the evolution of the viral envelope glycoprotein were monitored in rhesus macaques infected with a CCR5-tropic simian/human immunodeficiency virus (SHIV), SHIVSF162P4. Homologous neutralizing antibodies developed within the first month of infection in the majority of animals, and their titers were independent of the extent and duration of viral replication during chronic infection. The appearance of homologous neutralizing antibody responses was preceded by the appearance of amino acid changes in specific variable and conserved regions of gp120. Amino acid changes first appeared in the V1, V2, C2, and V3 regions and subsequently in the C3, V4, and V5 regions. Heterologous neutralizing antibody responses developed over time only in animals with sustained plasma viremia. Within 2 years postinfection the breadth of these responses was as broad as that observed in certain patients infected with HIV type 1 (HIV-1) for over a decade. Despite the development of broad anti-HIV-1 neutralizing antibody responses, viral replication persisted in these animals due to viral escape. Our studies indicate that cross-reactive neutralizing antibodies are elicited in a subset of SHIVSF162P4 infected macaques and that their development requires continuous viral replication for extended periods of time. More importantly, their late appearance does not prevent progression to disease. The availability of an animal model where cross-reactive anti-HIV neutralizing antibodies are developed may facilitate the identification of virologic and immunologic factors conducive to the development of such antibodies. 相似文献
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Many models of eyeblink conditioning assume that there is a simple linear relationship between the firing patterns of neurons in the interpositus nucleus and the time course of the conditioned response (CR). However, the complexities of muscle behaviour and plant dynamics call this assumption into question. We investigated the issue by implementing the most detailed model available of the rabbit nictitating membrane response (Bartha and Thompson in Biol Cybern 68:135-143, 1992a and in Biol Cybern 68:145-154, 1992b), in which each motor unit of the retractor bulbi muscle is represented by a Hill-type model, driven by a non-linear activation mechanism designed to reproduce the isometric force measurements of Lennerstrand (J Physiol 236:43-55, 1974). Globe retraction and NM extension are modelled as linked second order systems. We derived versions of the model that used a consistent set of SI units, were based on a physically realisable version of calcium kinetics, and used simulated muscle cross-bridges to produce force. All versions showed similar non-linear responses to two basic control strategies. (1) Rate-coding with no recruitment gave a sigmoidal relation between control signal and amplitude of CR, reflecting the measured relation between isometric muscle force and stimulation frequency. (2) Recruitment of similar strength motor units with no rate coding gave a sublinear relation between control signal and amplitude of CR, reflecting the increase in muscle stiffness produced by recruitment. However, the system response could be linearised by either a suitable combination of rate-coding and recruitment, or by simple recruitment of motor units in order of (exponentially) increasing strength. These plausible control strategies, either alone or in combination, would in effect present the cerebellum with the simplified virtual plant that is assumed in many models of eyeblink conditioning. Future work is therefore needed to determine the extent to which motor neuron firing is in fact linearly related to the nictitating membrane response. 相似文献
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