Cre-Dependent Expression of Multiple Transgenes in Isolated Neurons of the Adult Forebrain

Background: Transgenic mice with mosaic, Golgi-staining-like expression of enhanced green fluorescent protein (EGFP) have been very useful in studying the dynamics of neuronal structure and function. In order to further investigate the molecular events regulating structural plasticity, it would be useful to express multiple proteins in the same sparse neurons, allowing co-expression of functional proteins or co-labeling of subcellular compartments with other fluorescent proteins. However, it has been difficult to obtain reproducible expression in the same subset of neurons for direct comparison of neurons expressing different functional proteins. Principal Findings: Here we describe a Cre-transgenic line that allows reproducible expression of transgenic proteins of choice in a small number of neurons of the adult cortex, hippocampus, striatum, olfactory bulb, subiculum, hypothalamus, superior colliculus and amygdala. We show that using these Cre-transgenic mice, multiple Cre-dependent transgenes can be expressed together in the same isolated neurons. We also describe a Cre-dependent transgenic line expressing a membrane associated EGFP (EGFP-F). Crossed with the Cre-transgenic line, EGFP-F expression starts in the adolescent forebrain, is present in dendrites, dendritic protrusions, axons and boutons and is strong enough for acute or chronic in vivo imaging. Significance: This triple transgenic approach will aid the morphological and functional characterization of neurons in various Cre-dependent transgenic mice

The Biochemistry, Ultrastructure, and Subunit Assembly Mechanism of AMPA Receptors

The AMPA-type ionotropic glutamate receptors (AMPA-Rs) are tetrameric ligand-gated ion channels that play crucial roles in synaptic transmission and plasticity. Our knowledge about the ultrastructure and subunit assembly mechanisms of intact AMPA-Rs was very limited. However, the new studies using single particle EM and X-ray crystallography are revealing important insights. For example, the tetrameric crystal structure of the GluA2cryst construct provided the atomic view of the intact receptor. In addition, the single particle EM structures of the subunit assembly intermediates revealed the conformational requirement for the dimer-to-tetramer transition during the maturation of AMPA-Rs. These new data in the field provide new models and interpretations. In the brain, the native AMPA-R complexes contain auxiliary subunits that influence subunit assembly, gating, and trafficking of the AMPA-Rs. Understanding the mechanisms of the auxiliary subunits will become increasingly important to precisely describe the function of AMPA-Rs in the brain. The AMPA-R proteomics studies continuously reveal a previously unexpected degree of molecular heterogeneity of the complex. Because the AMPA-Rs are important drug targets for treating various neurological and psychiatric diseases, it is likely that these new native complexes will require detailed mechanistic analysis in the future. The current ultrastructural data on the receptors and the receptor-expressing stable cell lines that were developed during the course of these studies are useful resources for high throughput drug screening and further drug designing. Moreover, we are getting closer to understanding the precise mechanisms of AMPA-R-mediated synaptic plasticity

Hypocretin (orexin) loss in Alzheimer's disease.

Item does not contain fulltextSleep disturbances in Alzheimer's disease (AD) patients are associated with the severity of dementia and are often the primary reason for institutionalization. These sleep problems partly resemble core symptoms of narcolepsy, a sleep disorder caused by a general loss of the neurotransmitter hypocretin. AD is a neurodegenerative disorder targeting different brain areas and types of neurons. In this study, we assessed whether the neurodegenerative process of AD also affects hypothalamic hypocretin/orexin neurons. The total number of hypocretin-1 immunoreactive neurons was quantified in postmortem hypothalami of AD patients (n = 10) and matched controls (n = 10). In addition, the hypocretin-1 concentration was measured in postmortem ventricular cerebrospinal fluid of 24 AD patients and 25 controls (including the patients and controls in which the hypothalamic cell counts were performed). The number of hypocretin-1 immunoreactive neurons was significantly decreased by 40% in AD patients (median [25th-75th percentiles]); AD 12,935 neurons (9972-19,051); controls 21,002 neurons (16,439-25,765); p = 0.049). Lower cerebrospinal fluid (CSF) hypocretin-1 levels were found in AD patients compared with controls (AD: 275 pg/mL [197-317]; controls: 320 pg/mL [262-363]; p = 0.038). Two AD patients with documented excessive daytime sleepiness showed the lowest CSF hypocretin-1 concentrations (55 pg/mL and 76 pg/mL). We conclude that the hypocretin system is affected in advanced AD. This is reflected in a 40% decreased cell number, and 14% lower CSF hypocretin-1 levels.1 augustus 201

Hypocretin and melanin-concentrating hormone in patients with Huntington disease.

To evaluate whether hypocretin-1 (orexin-A) and melanin-concentrating hormone (MCH) neurotransmission are affected in patients with Huntington disease (HD), we immunohistochemically stained hypocretin and MCH neurons and estimated their total numbers in the lateral hypothalamus of both HD patients and matched controls. In addition, hypocretin-1 levels were determined in prefrontal cortical tissue and post-mortem ventricular cerebrospinal fluid (CSF) using a radioimmunoassay. The total number of hypocretin-1 neurons was significantly reduced by 30% in HD brains (P = 0.015), while the total number of MCH neurons was not significantly altered (P = 0.100). Levels of hypocretin-1 were 33% lower in the prefrontal cortex of the HD patients (P = 0.025), but ventricular CSF levels were similar to the control values (P = 0.306). Neuronal intranuclear and cytoplasmic inclusions of mutant huntingtin were present in all HD hypothalami, although with a variable distribution across different hypothalamic structures. We found a specific reduction in hypocretin signaling in patients with HD as MCH cell number was not significantly affected. It remains to be shown whether the moderate decrease in hypocretin neurotransmission could contribute to clinical symptoms. As the number of MCH-expressing neurons was not affected, alterations in MCH signaling are unlikely to have clinical effects in HD patients

A multiplex assay to rapidly exclude HLA-DQ2.5 and HLA-DQ8 expression in patients at risk for celiac disease

<p>Background: Celiac disease (CD) is an inflammatory disorder of the small intestine induced by gluten ingestion. CD has a strong genetic association with human leukocyte antigen (HLA)-DQ2.5 and HLA-DQ8. The absence of HLA-DQ2.5 and HLA-DQ8 has a strong negative predictive value for CD. Genetic screening of HLA-DQ2.5 and HLA-DQ8 in patients at risk is of great value.</p><p>Methods: We designed, developed, and validated a multiplex assay based on multiplex ligation-dependent probe amplification (MLPA) technology, allowing the simultaneous detection of DQA1*05-DQB1*02, encoding HLA-DQ2.5, and DQA1*03-DQB1*03:02, encoding HLA-DQ8. The amplified products were separated and identified using capillary electrophoresis.</p><p>Results: When compared with a polymerase chain reaction followed by single-strand conformation polymorphism/heteroduplex analysis, one discrepancy was found. Sequencing analysis showed that the developed MLPA assay result was correct. Furthermore, we demonstrated that the MLPA method is able to distinguish between the heterozygote and homozygote expression of HLA-DQ2.5 or HLA-DQ8.</p><p>Conclusions: This study shows that it is possible to rapidly and accurately screen for the absence of HLA-DQ2.5 and HLA-DQ8 using MLPA, excluding patients at risk for CD for further serological or histological follow-up. In addition, MLPA might be an accurate tool to screen for other specific HLA types in the context of disease association in a diagnostic laboratory setting.</p>

β-Catenin regulates excitatory postsynaptic strength at hippocampal synapses

The precise contribution of the cadherin–β-catenin synapse adhesion complex in the functional and structural changes associated with the pre- and postsynaptic terminals remains unclear. Here we report a requirement for endogenous β-catenin in regulating synaptic strength and dendritic spine morphology in cultured hippocampal pyramidal neurons. Ablating β-catenin after the initiation of synaptogenesis in the postsynaptic neuron reduces the amplitude of spontaneous excitatory synaptic responses without a concurrent change in their frequency and synapse density. The normal glutamatergic synaptic response is maintained by postsynaptic β-catenin in a cadherin-dependent manner and requires the C-terminal PDZ-binding motif of β-catenin but not the link to the actin cytoskeleton. In addition, ablating β-catenin in postsynaptic neurons accompanies a block of bidirectional quantal scaling of glutamatergic responses induced by chronic activity manipulation. In older cultures at a time when neurons have abundant dendritic spines, neurons ablated for β-catenin show thin, elongated spines and reduced proportion of mushroom spines without a change in spine density. Collectively, these findings suggest that the cadherin–β-catenin complex is an integral component of synaptic strength regulation and plays a basic role in coupling synapse function and spine morphology

General Report & Recommendations in Predictive, Preventive and Personalised Medicine 2012: White Paper of the European Association for Predictive, Preventive and Personalised Medicine

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Quantitative analysis of mRNA-1273 COVID-19 vaccination response in immunocompromised adult hematology patients.

Vaccination guidelines for patients treated for hematological diseases are typically conservative. Given their high risk for severe coronavirus infectious disease 2019 (COVID-19) it is important to identify those patients that benefit from vaccination. We prospectively quantified serum IgG antibodies to spike subunit 1 (S1)antigensduring and after 2-dose mRNA-1273 (Spikevax/Moderna) vaccination in hematology patients. Obtaining S1 IgG≥300 binding antibody units (BAU)/mlwas considered adequate as it represents the lower level of S1 IgG concentration obtained in healthy individuals andit correlates with potent virus neutralization. Selected patients (n=723) were severely immunocompromised due to their disease or treatment thereof. Nevertheless, more than 50% of patients obtained S1 IgG ≥300 BAU/ml after 2-dose mRNA-1273. All patients with sickle cell disease or chronic myeloid leukemia obtained adequate antibody concentrations.Around 70% ofpatients with chronic graftversushostdisease (GvHD), multiple myeloma, or untreated chronic lymphocytic leukemia (CLL) obtained S1 IgG≥300 BAU/ml.Ruxolitinib or hypomethylating therapy but not high-dose chemotherapy blunted responses in myeloid malignancies. Responses inlymphoma patients, CLL patients on ibrutinib, and chimeric antigen receptor T cell recipients were low.The minimal time-interval after autologous hematopoietic cell transplantation (HCT) to reach adequate concentrations was <2 months for multiple myeloma, 8 months for lymphoma, and 4-6 months after allogeneic HCT.Serum IgG4, absolute B and NK cell number and number of immunosuppressants predicted S1 IgG ≥300 BAU/ml. Hematology patients on chemotherapy, shortly after HCT, or with chronic GvHD should not be precluded from vaccination. Netherlands Trial Register NL9553

Quantitative analysis of mRNA-1273 COVID-19 vaccination response in immunocompromised adult hematology patients

Vaccination guidelines for patients treated for hematological diseases are typically conservative. Given their high risk for severe COVID-19, it is important to identify those patients that benefit from vaccination. We prospectively quantified serum immunoglobulin G (IgG) antibodies to spike subunit 1 (S1) antigens during and after 2-dosemRNA-1273 (Spikevax/Moderna) vaccination in hematology patients. Obtaining S1 IgG >= 300 binding antibody units (BAUs)/mLwas considered adequate as it represents the lower level of S1 IgG concentration obtained in healthy individuals, and it correlates with potent virus neutralization. Selected patients (n = 723) were severely immunocompromised owing to their disease or treatment thereof. Nevertheless, >= 50% of patients obtained S1 IgG >= 300 BAUs/mL after 2-dosemRNA-1273. All patients with sickle cell disease or chronicmyeloid leukemia obtained adequate antibody concentrations. Around 70% of patients with chronic graft-versus-host disease (cGVHD), multiple myeloma, or untreated chronic lymphocytic leukemia (CLL) obtained S1 IgG >= 300 BAUs/mL. Ruxolitinib or hypomethylating therapy but not high-dose chemotherapy blunted responses inmyeloidmalignancies. Responses in patients with lymphoma, patients with CLL on ibrutinib, and chimeric antigen receptor T-cell recipients were low. The minimal time interval after autologous hematopoietic cell transplantation (HCT) to reach adequate concentrations was = 300 BAUs/mL. Hematology patients on chemotherapy, shortly after HCT, or with cGVHD should not be precluded fromvaccination.Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease