Microsurgical clipping vs Woven EndoBridge (WEB) device for the management of unruptured wide-neck bifurcation aneurysms

Neurosurgical Review - The Woven EndoBridge device (WEB) was introduced in 2010 to treat wide-neck bifurcation aneurysms (WNBAs). Three landmark studies have been conducted to assess its safety and...     

CpG-A and CpG-B oligonucleotides differentially enhance human peptide-specific primary and memory CD8+ T-cell responses in vitro

Two distinct types of CpG oligodeoxynucleotide (ODN) have been identified that differ in their capacity to stimulate antigen-presenting cells: CpG-A induces high amounts of interferon-alpha (IFN-alpha) and IFN-beta in plasmacytoid dendritic cells (PDCs), whereas CpG-B induces PDC maturation and is a potent activator of B cells but stimulates only small amounts of IFN-alpha and IFN-beta. Here we examined the ability of these CpG ODNs to enhance peptide-specific CD8+ T-cell responses in human peripheral blood mononuclear cells (PBMCs). The frequency of influenza matrix-specific "memory" CD8+ T cells was increased by both types of CpG ODN, whereas the frequency of Melan-A specific "naive" CD8+ T cells increased on stimulation with CpG-B but not with CpG-A. The presence of PDCs in PBMCs was required for this CpG ODN-mediated effect. The expanded cells were cytotoxic and produced IFN- on peptide restimulation. Soluble factors induced by CpG-A but not CpG-B increased the granzyme-B content and cytotoxicity of established CD8+ T-cell clones, each of which was IFN-alpha/-beta dependent. In conclusion, CpG-B seems to be superior for priming CD8+ T-cell responses, and CpG-A selectively enhances memory CD8+ T-cell responses and induces cytotoxicity. These results demonstrate distinct functional properties of CpG-A and CpG-B with regard to CD8 T cells.     

Differential effect of glucose ingestion on the neural processing of food stimuli in lean and overweight adults

Eating behavior is crucial in the development of obesity and Type 2 diabetes. To further investigate its regulation, we studied the effects of glucose versus water ingestion on the neural processing of visual high and low caloric food cues in 12 lean and 12 overweight subjects by functional magnetic resonance imaging. We found body weight to substantially impact the brain's response to visual food cues after glucose versus water ingestion. Specifically, there was a significant interaction between body weight, condition (water versus glucose), and caloric content of food cues. Although overweight subjects showed a generalized reduced response to food objects in the fusiform gyrus and precuneus, the lean group showed a differential pattern to high versus low caloric foods depending on glucose versus water ingestion. Furthermore, we observed plasma insulin and glucose associated effects. The hypothalamic response to high caloric food cues negatively correlated with changes in blood glucose 30 min after glucose ingestion, while especially brain regions in the prefrontal cortex showed a significant negative relationship with increases in plasma insulin 120 min after glucose ingestion. We conclude that the postprandial neural processing of food cues is highly influenced by body weight especially in visual areas, potentially altering visual attention to food. Furthermore, our results underline that insulin markedly influences prefrontal activity to high caloric food cues after a meal, indicating that postprandial hormones may be potential players in modulating executive control. Hum Brain Mapp 35:918–928, 2014. © 2013 Wiley Periodicals, Inc.     

Resting‐state functional connectivity of the human hypothalamus

The hypothalamus is of enormous importance for multiple bodily functions such as energy homeostasis. Especially, rodent studies have greatly contributed to our understanding how specific hypothalamic subregions integrate peripheral and central signals into the brain to control food intake. In humans, however, the neural circuitry of the hypothalamus, with its different subregions, has not been delineated. Hence, the aim of this study was to map the hypothalamus network using resting‐state functional connectivity (FC) analyses from the medial hypothalamus (MH) and lateral hypothalamus (LH) in healthy normal‐weight adults (n = 49). Furthermore, in a separate sample, we examined differences within the LH and MH networks between healthy normal‐weight (n = 25) versus overweight/obese adults (n = 23). FC patterns from the LH and MH revealed significant connections to the striatum, thalamus, brainstem, orbitofrontal cortex, middle and posterior cingulum and temporal brain regions. However, our analysis revealed subtler distinctions within hypothalamic subregions. The LH was functionally stronger connected to the dorsal striatum, anterior cingulum, and frontal operculum, while the MH showed stronger functional connections to the nucleus accumbens and medial orbitofrontal cortex. Furthermore, overweight/obese participants revealed heightened FC in the orbitofrontal cortex and nucleus accumbens within the MH network. Our results indicate that the MH and LH network are tapped into different parts of the dopaminergic circuitry of the brain, potentially modulating food reward based on the functional connections to the ventral and dorsal striatum, respectively. In obese adults, FC changes were observed in the MH network. Hum Brain Mapp 35:6088–6096, 2014. © 2014 Wiley Periodicals, Inc.     

OutKnocker: a web tool for rapid and simple genotyping of designer nuclease edited cell lines

The application of designer nucleases allows the induction of DNA double-strand breaks (DSBs) at user-defined genomic loci. Due to imperfect DNA repair mechanisms, DSBs can lead to alterations in the genomic architecture, such as the disruption of the reading frame of a critical exon. This can be exploited to generate somatic knockout cell lines. While high genome editing activities can be achieved in various cellular systems, obtaining cell clones that contain all-allelic frameshift mutations at the target locus of interest remains a laborious task. To this end, we have developed an easy-to-follow deep sequencing workflow and the evaluation tool OutKnocker (www.OutKnocker.org), which allows convenient, reliable, and cost-effective identification of knockout cell lines.Advances in targeted genome editing technologies have opened new avenues for addressing challenging questions in the field of life sciences. The recent introduction of designer nucleases such as ZFNs (Carroll 2011), TALENs (Miller et al. 2011), or CRISPR/Cas systems (Jinek et al. 2012; Cong et al. 2013; Mali et al. 2013) allows for highly efficient, flexible, and specific induction of DNA double-strand breaks (DSB) in eukaryotic genomes. DSBs trigger two distinct repair pathways that can be exploited to specifically modify gene architecture (Carroll 2011). While the process of homologous recombination (HR) accurately repairs DSBs using the sister chromatid as a template, nonhomologous end-joining (NHEJ) repair is an error-prone end-joining mismatch repair pathway that frequently leads to genetic alterations (Lieber 2010; Chiruvella et al. 2013). Providing a donor construct with appropriate homology arms as a template, the pathway of DSB-triggered HR can be used to site-specifically introduce heterologous genetic material into cells (Carroll 2011). For example, it is possible to generate gene knockouts in somatic cell lines by introducing marker cassettes with premature stop codons. However, this strategy is time consuming and laborious and therefore not optimal for high-throughput approaches. The DSB-induced NHEJ repair pathway, on the other hand, leads to insertions or deletions (indels) (Lieber 2010) that can result in frameshift mutations and thus loss-of-function phenotypes if located within early coding exons.While in HR-based genome editing approaches marker genes can be introduced to select for the desired genotype starting from a polyclonal cell culture, frameshift mutations induced by NHEJ are difficult to select for unless the editing event provides a survival benefit. To this end, single-cell cloning and subsequent sequencing of the genetic locus is required to obtain cells with the desired gene disruption. Sanger sequencing is most commonly used to identify modified alleles. However, in addition to being costly, this method requires a locus-specific PCR to be subcloned in order to sequence single alleles, and thus is not practical for large-scale projects. Moreover, the ploidy of the genome may vary between cell lines and even between loci, which may require the sequencing of a considerable number of PCR subclones to reliably identify cell clones with all-allelic frameshift mutations. Small benchtop deep sequencing machines can achieve a far greater throughput. Theoretically, even low sequencing capacities are sufficient to analyze hundreds of clones in parallel, without the need to subclone PCR products. However, analysis of deep sequencing data remains challenging and no streamlined workflow has been described that would allow full exploitation of deep sequencing capacities in gene disruption projects.Here we describe OutKnocker, a web-based application that facilitates the analysis of deep sequencing data to identify knockout cells obtained from designer nuclease-mediated genome editing. We aimed at developing an evaluation tool to genotype single-cell clones at a confined genomic region for indel mutations, as they are typically induced by designer nuclease targeting. As such, we established an algorithm that focuses on identifying a single indel event per sequencing read around a predefined target site, while ignoring SNPs or point mutations originated during sequencing. Optionally, our software also allows the detection of specific point mutations introduced by targeted mutagenesis. To fully exploit sequencing capacities, OutKnocker was designed to analyze data of sequencing runs that have been multiplexed to evaluate the same or different genomic target regions in parallel, while only requiring a limited number of unidirectional sequencing reads. OutKnocker is operated from a web browser making it conveniently accessible to any user.     

Empagliflozin Improves Insulin Sensitivity of the Hypothalamus in Humans With Prediabetes: A Randomized,Double-Blind,Placebo-Controlled,Phase 2 Trial

OBJECTIVEInsulin action in the human brain reduces food intake, improves whole-body insulin sensitivity, and modulates body fat mass and its distribution. Obesity and type 2 diabetes are often associated with brain insulin resistance, resulting in impaired brain-derived modulation of peripheral metabolism. So far, no pharmacological treatment for brain insulin resistance has been established. Since sodium–glucose cotransporter 2 (SGLT2) inhibitors lower glucose levels and modulate energy metabolism, we hypothesized that SGLT2 inhibition may be a pharmacological approach to reverse brain insulin resistance.RESEARCH DESIGN AND METHODSIn this randomized, double-blind, placebo-controlled clinical trial, 40 patients (mean ± SD; age 60 ± 9 years; BMI 31.5 ± 3.8 kg/m²) with prediabetes were randomized to receive 25 mg empagliflozin every day or placebo. Before and after 8 weeks of treatment, brain insulin sensitivity was assessed by functional MRI combined with intranasal administration of insulin to the brain.RESULTSWe identified a significant interaction between time and treatment in the hypothalamic response to insulin. Post hoc analyses revealed that only empagliflozin-treated patients experienced increased hypothalamic insulin responsiveness. Hypothalamic insulin action significantly mediated the empagliflozin-induced decrease in fasting glucose and liver fat.CONCLUSIONSOur results corroborate insulin resistance of the hypothalamus in humans with prediabetes. Treatment with empagliflozin for 8 weeks was able to restore hypothalamic insulin sensitivity, a favorable response that could contribute to the beneficial effects of SGLT2 inhibitors. Our findings position SGLT2 inhibition as the first pharmacological approach to reverse brain insulin resistance, with potential benefits for adiposity and whole-body metabolism.     

Stem cell-like plasticity of naïve and distinct memory CD8+ T cell subsets

Most models regarding the ‘clonal’ origin of CD8⁺ T cell effector and memory subset diversification suggest that during the first contact of a naïve T cell with the priming antigen-presenting cell major decisions for subsequent differentiation are made. Data using novel single-cell T cell tracking technologies demonstrate that a single naïve CD8⁺ T cell can give rise to virtually all different subtypes of effector and memory T cells, and direct major determinants of subset diversification to the time period beyond the first cell division. Thereby, some ‘stem cell-like’ characteristics typical for naïve T cells are probably still maintained within distinct subsets of memory T cells. These observations have direct consequences for clinical applications like adoptive T cell therapy.     

Dual depolarization responses generated within the same lateral septal neurons by TRPC4-containing channels

In the central nervous system, canonical transient receptor potential (TRPC) channels have been implicated in mediating neuronal excitation induced by stimulating metabotropic receptors, including group 1 metabotropic glutamate receptors (mGluRs). Lateral septal (LS) neurons express high levels of TRPC4 and group I mGluRs. However, to what extent native TRPC4-containing channels (TRPC4-cc) are activated as well as the impact of different levels of TRPC4-cc activation on neuronal excitability remain elusive. Here, we report that stimulating LS neurons with group I mGluR agonist, (S)-3,5-DHPG, causes either an immediate increase in firing rate or an initial burst followed by a pause of firing, which can be correlated with below-threshold-depolarization (BTD) or above-threshold-plateau-depolarization (ATPD), respectively, in whole-cell recordings. The early phase of BTD and the entire ATPD are completely absent in neurons from TRPC4^?/? mice. Moreover, in the same LS neurons, BTD can be converted to ATPD at more depolarized potentials or with a brief current injection, suggesting that BTD and ATPD may represent partial and full activations of TRPC4-cc, respectively. We show that coincident mGluR stimulation and depolarization is required to evoke strong TRPC4-cc current, and Na⁺ and Ca²⁺ influx, together with dynamic changes of intracellular Ca²⁺, are essential for ATPD induction. Our results suggest that TRPC4-cc integrates metabotropic receptor stimulation with intracellular Ca²⁺ signals to generate two interconvertible depolarization responses to affect excitability of LS neurons in distinct fashions.