Regulation of human microglial gene expression and function via RNAase-H active antisense oligonucleotides in vivo in Alzheimer's disease.

Background: Microglia play important roles in maintaining brain homeostasis and neurodegeneration. The discovery of genetic variants in genes predominately or exclusively expressed in myeloid cells, such as Apolipoprotein E (APOE) and triggering receptor expressed on myeloid cells 2 (TREM2), as the strongest risk factors for Alzheimer's disease (AD) highlights the importance of microglial biology in the brain. The sequence, structure and function of several microglial proteins are poorly conserved across species, which has hampered the development of strategies aiming to modulate the expression of specific microglial genes.

A truncated HIV Tat demonstrates potent and specific latency reversal activity.

A major barrier to HIV-1 cure is caused by the pool of latently infected CD4 T-cells that persist under combination antiretroviral therapy (cART). This latent reservoir is capable of producing replication-competent infectious viruses once prolonged suppressive cART is withdrawn. Inducing the reactivation of HIV-1 gene expression in T-cells harboring a latent provirus in people living with HIV-1 under cART may result in depletion of this latent reservoir due to cytopathic effects or immune clearance.

Is the forming of neuronal network activity in human-induced pluripotent stem cells important for the detection of drug-induced seizure risks?

Background: Functional network activity is a characteristic for neuronal cells, and the complexity of the network activity represents the necessary substrate to support complex brain functions. Drugs that drastically increase the neuronal network activity may have a potential higher risk for seizures in human. Although there has been some recent considerable progress made using cultures from different types of human-induced pluripotent stem cell (hiPSC) derived neurons, one of the primary limitations is the lack of - or very low - network activity.

Effects of microglial depletion and TREM2 deficiency on Aβ plaque burden and neuritic plaque tau pathology in 5XFAD mice.

Dystrophic neuronal processes harboring neuritic plaque (NP) tau pathology are found in association with Aβ plaques in Alzheimer's disease (AD) brain. Microglia are also in proximity to these plaques and microglial gene variants are known risk factors in AD, including loss-of-function variants of TREM2. We have further investigated the role of Aβ plaque-associated microglia in 5XFAD mice in which NP tau pathology forms after intracerebral injection of AD brain-derived pathologic tau (AD-tau), focusing on the consequences of reduced TREM2 expression and microglial depletion after treatment with the colony-stimulating factor 1 (CSFR1) inhibitor, PLX3397.

Differential gene expression, irrespective of circulating Hepatitis B Surface Antigen levels, between Inactive Carrier and Nucleos(t)ide Analogue-Treated Hepatitis B Virus patients.

Long-term viremia control in chronic HBV patients occurs either spontaneously in inactive carrier (IC) patients or therapy-induced by nucleos(t)ide analogues (NUC). To better understand the characteristics of viremia control, we evaluated gene expression in purified leukocyte subsets from IC versus NUC-treated patients, and evaluated the putative modulatory effects of hepatitis B surface antigen (HBsAg). We observed that gene expression in NUC-treated patients differed markedly from IC patients, especially in dendritic cells, monocytes, and CD8+ T cells, while serum HBsAg levels had little effect.

Tales of 1,008 small molecules: phenomic profiling through live-cell imaging in a panel of reporter cell lines.

Phenomic profiles are high-dimensional sets of readouts that can comprehensively capture the biological impact of chemical and genetic perturbations in cellular assay systems. Phenomic profiling of compound libraries can be used for compound target identification or mechanism of action (MoA) prediction and other applications in drug discovery. To devise an economical set of phenomic profiling assays, we assembled a library of 1,008 approved drugs and well-characterized tool compounds manually annotated to 218 unique MoAs, and we profiled each compound at four concentrations in live-cell, high-content imaging screens against a panel of 15 reporter cell lines, which expressed a diverse set of fluorescent organelle and pathway markers in three distinct cell lineages.

Genetically Engineered iPSC-Derived FTDP-17 MAPT Neurons Display Mutation-Specific Neurodegenerative and Neurodevelopmental Phenotypes.

Tauopathies such as frontotemporal dementia (FTD) remain incurable to date, partially due to the lack of translational in vitro disease models. The MAPT gene, encoding the microtubule-associated protein tau, has been shown to play an important role in FTD pathogenesis. Therefore, we used zinc finger nucleases to introduce two MAPT mutations into healthy donor induced pluripotent stem cells (iPSCs).

Chronic drug-induced effects on contractile motion properties and cardiac biomarkers in human induced pluripotent stem cell-derived cardiomyocytes.

Background And Purpose: In the pharmaceutical industry risk assessments of chronic cardiac safety liabilities are mostly performed during late stages of preclinical drug development using in vivo animal models. Here, we explored the potential of human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) to detect chronic cardiac risks such as drug-induced cardiomyocyte toxicity.

Experimental Approach: Video microscopy-based motion field imaging was applied to evaluate the chronic effect (over 72 h) of cardiotoxic drugs on the contractile motion of hiPS-CMs.

Age-dependent concomitant changes in synaptic dysfunction and GABAergic pathway in the APP/PS1 mouse model.

Synaptic dysfunction is a well-documented manifestation in animal models of Alzheimer's disease pathology. In this context, numerous studies have documented reduction in the functionality of synapses in various models. In addition, recent research has shed more light on increased excitability and its link to seizures and seizure-like activities in AD patients as well as in mouse models.

In Vitro Model for Hepatotoxicity Studies Based on Primary Human Hepatocyte Cultivation in a Perfused 3D Bioreactor System.

Accurate prediction of the potential hepatotoxic nature of new pharmaceuticals remains highly challenging. Therefore, novel in vitro models with improved external validity are needed to investigate hepatic metabolism and timely identify any toxicity of drugs in humans. In this study, we examined the effects of diclofenac, as a model substance with a known risk of hepatotoxicity in vivo, in a dynamic multi-compartment bioreactor using primary human liver cells.

Functional and Transcriptional Characterization of Histone Deacetylase Inhibitor-Mediated Cardiac Adverse Effects in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Unlabelled: Histone deacetylase (HDAC) inhibitors possess therapeutic potential to reverse aberrant epigenetic changes associated with cancers, neurological diseases, and immune disorders. Unfortunately, clinical studies with some HDAC inhibitors displayed delayed cardiac adverse effects, such as atrial fibrillation and ventricular tachycardia. However, the underlying molecular mechanism(s) of HDAC inhibitor-mediated cardiotoxicity remains poorly understood and is difficult to detect in the early stages of preclinical drug development because of a delayed onset of effects.

MELK-T1, a small-molecule inhibitor of protein kinase MELK, decreases DNA-damage tolerance in proliferating cancer cells.

Maternal embryonic leucine zipper kinase (MELK), a serine/threonine protein kinase, has oncogenic properties and is overexpressed in many cancer cells. The oncogenic function of MELK is attributed to its capacity to disable critical cell-cycle checkpoints and reduce replication stress. Most functional studies have relied on the use of siRNA/shRNA-mediated gene silencing.

Integrating High-Dimensional Transcriptomics and Image Analysis Tools into Early Safety Screening: Proof of Concept for a New Early Drug Development Strategy.

During drug discovery and development, the early identification of adverse effects is expected to reduce costly late-stage failures of candidate drugs. As risk/safety assessment takes place rather late during the development process and due to the limited ability of animal models to predict the human situation, modern unbiased high-dimensional biology readouts are sought, such as molecular signatures predictive for in vivo response using high-throughput cell-based assays. In this theoretical proof of concept, we provide findings of an in-depth exploration of a single chemical core structure.

Upregulation of MAPK Negative Feedback Regulators and RET in Mutant ALK Neuroblastoma: Implications for Targeted Treatment.

Purpose: Activating ALK mutations are present in almost 10% of primary neuroblastomas and mark patients for treatment with small-molecule ALK inhibitors in clinical trials. However, recent studies have shown that multiple mechanisms drive resistance to these molecular therapies. We anticipated that detailed mapping of the oncogenic ALK-driven signaling in neuroblastoma can aid to identify potential fragile nodes as additional targets for combination therapies.

Microarray profiling of DNA extracted from FFPE tissues using SNP 6.0 Affymetrix platform.

High-density oligonucleotide microarrays are commonly used for GWAS studies as well as for tumor genome alteration identifications. The recent Affymetrix Genome-Wide SNP 6.0 microarray generation has two major advantages: (1) showing high genome coverage and (2) starting with very small amount of DNA material.

The ontogeny of drug metabolizing enzymes and transporters in the rat.

Knowledge of the ontogeny of the various systems involved in distribution and elimination of drugs is important for adequate interpretation of the findings during safety studies in juvenile animals. The present study was designed to collect information on plasma concentrations of total protein and albumin, enzyme activity and mRNA expression of cytochrome P450 isoenzymes (CYP1A1/2, CYP2B1/2, CYP2E1, CYP3A1/2, and CYP4A1), carboxylesterase and thyroxin glucuronidation (T4-GT) activity in liver microsomes, and mRNA expression of transporters (Mdr1a/b, Mrp1-3 and 6, Bsep and Bcrp, Oct1-2, Oat1-3 and Oatp1a4) in liver, kidney and brain tissue during development in Sprague-Dawley rats. Enzyme activities were determined by measuring the metabolism of marker substrates; expression of mRNAs was assessed using RTq-PCR.

Genome-wide copy number alterations detection in fresh frozen and matched FFPE samples using SNP 6.0 arrays.

SNP arrays offer the opportunity to get a genome-wide view on copy number alterations and are increasingly used in oncology. DNA from formalin-fixed paraffin-embedded material (FFPE) is partially degraded which limits the application of those technologies for retrospective studies. We present the use of Affymetrix GeneChip SNP6.

Diarylquinolines are bactericidal for dormant mycobacteria as a result of disturbed ATP homeostasis.

An estimated one-third of the world population is latently infected with Mycobacterium tuberculosis. These nonreplicating, dormant bacilli are tolerant to conventional anti-tuberculosis drugs, such as isoniazid. We recently identified diarylquinoline R207910 (also called TMC207) as an inhibitor of ATP synthase with a remarkable activity against replicating mycobacteria.

Alterations in mucosal immunity identified in the colon of patients with irritable bowel syndrome.

Background & Aims: Irritable bowel syndrome (IBS) has been associated with mucosal dysfunction, mild inflammation, and altered colonic bacteria. We used microarray expression profiling of sigmoid colon mucosa to assess whether there are stably expressed sets of genes that suggest there are objective molecular biomarkers associated with IBS.

Methods: Gene expression profiling was performed using Human Genome U133 Plus 2.

Alterations in the brain-gut axis underlying visceral chemosensitivity in Nippostrongylus brasiliensis-infected mice.

Background & Aims: Visceral hypersensitivity, a hallmark of irritable bowel syndrome, is generally considered to be mechanosensitive in nature and mediated via spinal afferents. Both stress and inflammation are implicated in visceral hypersensitivity, but the underlying molecular mechanisms of visceral hypersensitivity are unknown.

Methods: Mice were infected with Nippostrongylus brasiliensis (Nb) larvae, exposed to environmental stress and the following separate studies performed 3-4 weeks later.

Alterations in expression of p11 and SERT in mucosal biopsy specimens of patients with irritable bowel syndrome.

Background & Aims: The pathophysiology of irritable bowel syndrome (IBS) remains enigmatic; abnormalities in serotonin metabolism have been implicated. Two proteins that influence the function of serotonin and serotonergic receptors are serotonin transporter protein (SERT or soluble carrier protein, SLC6A4) and p11 (S-100A10, or calpactin I light chain). Both proteins are reported to be associated with depression-like states, a frequent comorbid condition in IBS.