Microglia in retinal angiogenesis and diabetic retinopathy.

Diabetic retinopathy has a high probability of causing visual impairment or blindness throughout the disease progression and is characterized by the growth of new blood vessels in the retina at an advanced, proliferative stage. Microglia are a resident immune population in the central nervous system, known to play a crucial role in regulating retinal angiogenesis in both physiological and pathological conditions, including diabetic retinopathy. Physiologically, they are located close to blood vessels and are essential for forming new blood vessels (neovascularization). In diabetic retinopathy, microglia become widely activated, showing a distinct polarization phenotype that leads to their accumulation around neovascular tufts. These activated microglia induce pathogenic angiogenesis through the secretion of various angiogenic factors and by regulating the status of endothelial cells. Interestingly, some subtypes of microglia simultaneously promote the regression of neovascularization tufts and normal angiogenesis in neovascularization lesions. Modulating the state of microglial activation to ameliorate neovascularization thus appears as a promising potential therapeutic approach for managing diabetic retinopathy.

Structure, function, and recombinant production of EGFL7.

The secreted factor Epidermal growth factor-like protein 7 (EGFL7) is involved in angiogenesis, vasculogenesis, as well as neurogenesis. Importantly, EGFL7 is also implicated in various pathological conditions, including tumor angiogenesis in human cancers. Thus, understanding the mechanisms through which EGFL7 regulates and promotes blood vessel formation is of clear practical importance. One principle means by which EGFL7's function is investigated is via the expression and purification of the recombinant protein. This mini-review describes three methods used to produce recombinant EGFL7 protein. First, a brief overview of EGFL7's genetics, structure, and function is provided. This is followed by an examination of the advantages and disadvantages of three common expression systems used in the production of recombinant EGFL7; (i) Escherichia coli (E. coli), (ii) human embryonic kidney (HEK) 293 cells or other mammalian cells, and (iii) a baculovirus-based Sf9 insect cell expression system. Based on the available evidence, we conclude that the baculovirus-based Sf9 insect cell expression currently has the advantages of producing active recombinant EGFL7 in the native conformation with the presence of acceptable posttranslational modifications, while providing sufficient yield and stability for experimental purposes.

The origin of brain malignancies at the blood-brain barrier.

Despite improvements in extracranial therapy, survival rate for patients suffering from brain metastases remains very poor. This is coupled with the incidence of brain metastases continuing to rise. In this review, we focus on core contributions of the blood-brain barrier to the origin of brain metastases. We first provide an overview of the structure and function of the blood-brain barrier under physiological conditions. Next, we discuss the emerging idea of a pre-metastatic niche, namely that secreted factors and extracellular vesicles from a primary tumor site are able to travel through the circulation and prime the neurovasculature for metastatic invasion. We then consider the neurotropic mechanisms that circulating tumor cells possess or develop that facilitate disruption of the blood-brain barrier and survival in the brain's parenchyma. Finally, we compare and contrast brain metastases at the blood-brain barrier to the primary brain tumor, glioma, examining the process of vessel co-option that favors the survival and outgrowth of brain malignancies.

EGFL7 loss correlates with increased VEGF-D expression, upregulating hippocampal adult neurogenesis and improving spatial learning and memory.

Neural stem cells reside in the subgranular zone, a specialized neurogenic niche of the hippocampus. Throughout adulthood, these cells give rise to neurons in the dentate gyrus, playing an important role in learning and memory. Given that these core cognitive processes are disrupted in numerous disease states, understanding the underlying mechanisms of neural stem cell proliferation in the subgranular zone is of direct practical interest. Here, we report that mature neurons, neural stem cells and neural precursor cells each secrete the neurovascular protein epidermal growth factor-like protein 7 (EGFL7) to shape this hippocampal niche. We further demonstrate that EGFL7 knock-out in a Nestin-CreERT2-based mouse model produces a pronounced upregulation of neurogenesis within the subgranular zone. RNA sequencing identified that the increased expression of the cytokine VEGF-D correlates significantly with the ablation of EGFL7. We substantiate this finding with intraventricular infusion of VEGF-D upregulating neurogenesis in vivo and further show that VEGF-D knock-out produces a downregulation of neurogenesis. Finally, behavioral studies in EGFL7 knock-out mice demonstrate greater maintenance of spatial memory and improved memory consolidation in the hippocampus by modulation of pattern separation. Taken together, our findings demonstrate that both EGFL7 and VEGF-D affect neurogenesis in the adult hippocampus, with the ablation of EGFL7 upregulating neurogenesis, increasing spatial learning and memory, and correlating with increased VEGF-D expression.

N-Cyanopiperazines as Specific Covalent Inhibitors of the Deubiquitinating Enzyme UCHL1.

Cyanamides have emerged as privileged scaffolds in covalent inhibitors of deubiquitinating enzymes (DUBs). However, many compounds with a cyanopyrrolidine warhead show cross-reactivity toward small subsets of DUBs or toward the protein deglycase PARK7/DJ-1, hampering their use for the selective perturbation of a single DUB in living cells. Here, we disclose N'-alkyl,N-cyanopiperazines as structures for covalent enzyme inhibition with exceptional specificity for the DUB UCHL1 among 55 human deubiquitinases and with effective target engagement in cells. Notably, transitioning from 5-membered pyrrolidines to 6-membered heterocycles eliminated PARK7 binding and introduced context-dependent reversibility of the isothiourea linkage to the catalytic cysteine of UCHL1. Compound potency and specificity were analysed by a range of biochemical assays and with a crystal structure of a cyanopiperazine in covalent complex with UCHL1. The structure revealed a compound-induced conformational restriction of the cross-over loop, which underlies the observed inhibitory potencies. Through the rationalization of specificities of different cyanamides, we introduce a framework for the investigation of protein reactivity of bioactive nitriles of this compound class. Our results represent an encouraging case study for the refining of electrophilic compounds into chemical probes, emphasizing the potential to engineer specificity through subtle chemical modifications around the warhead.

Dose-response relation between the duration of a cognitively challenging bout of physical exercise and children's cognition.

Acute bouts of physical exercise have the potential to benefit children's cognition. Inconsistent evidence calls for systematic investigations of dose-response relations between quantitative (intensity and duration) and qualitative (modality) exercise characteristics. Thus, in this study the optimal duration of an acute cognitively challenging physical exercise to benefit children's cognition was investigated, also exploring the moderating role of individual characteristics. In a within-subject experimental design, 104 children (Mage = 11.5, SD = 0.8, 51% female) participated weekly in one of four exergaming conditions of different durations (5, 10, 15, 20 min) followed by an Attention Network task (ANT-R). Exergame sessions were designed to keep physical intensity constant (65% HRmax ) and to have a high cognitive challenge level (adapted to the individual ongoing performance). Repeated measures ANOVAs revealed a significant effect of exercise duration on reaction times (RTs; p = 0.009, ƞ2 p = 0.11), but not on response accuracy. Post hoc analyses showed faster information processing speed after 15 min of exercise compared to 10 min (p = 0.019, ƞ2 p = 0.09). Executive control, alerting and orienting performances and interactions were unaffected by exercise duration (ps > 0.05). Among individual characteristics, habitual physical activity moderated duration effects on RTs. For more active children, exercise duration influenced the interaction between executive control and orienting (p = 0.034; ƞ2 p = 0.17) with best performances after the 15 min duration. Results suggest that an acute 15 min cognitively high-challenging bout of physical exercise enhances allocable resources, which in turn facilitate information processing, and-for more active children only-also executive processes. Results are interpreted according to the arousal theory and cognitive stimulation hypothesis.

Prevention of age-associated neuronal hyperexcitability with improved learning and attention upon knockout or antagonism of LPAR2.

Recent studies suggest that synaptic lysophosphatidic acids (LPAs) augment glutamate-dependent cortical excitability and sensory information processing in mice and humans via presynaptic LPAR2 activation. Here, we studied the consequences of LPAR2 deletion or antagonism on various aspects of cognition using a set of behavioral and electrophysiological analyses. Hippocampal neuronal network activity was decreased in middle-aged LPAR2-/- mice, whereas hippocampal long-term potentiation (LTP) was increased suggesting cognitive advantages of LPAR2-/- mice. In line with the lower excitability, RNAseq studies revealed reduced transcription of neuronal activity markers in the dentate gyrus of the hippocampus in naïve LPAR2-/- mice, including ARC, FOS, FOSB, NR4A, NPAS4 and EGR2. LPAR2-/- mice behaved similarly to wild-type controls in maze tests of spatial or social learning and memory but showed faster and accurate responses in a 5-choice serial reaction touchscreen task requiring high attention and fast spatial discrimination. In IntelliCage learning experiments, LPAR2-/- were less active during daytime but normally active at night, and showed higher accuracy and attention to LED cues during active times. Overall, they maintained equal or superior licking success with fewer trials. Pharmacological block of the LPAR2 receptor recapitulated the LPAR2-/- phenotype, which was characterized by economic corner usage, stronger daytime resting behavior and higher proportions of correct trials. We conclude that LPAR2 stabilizes neuronal network excitability upon aging and allows for more efficient use of resting periods, better memory consolidation and better  performance in tasks requiring high selective attention. Therapeutic LPAR2 antagonism may alleviate aging-associated cognitive dysfunctions.

Cognition, psychosocial functioning, and health-related quality of life among childhood cancer survivors.

Long-term sequelae of cancer and its treatment render childhood cancer (CC) survivors vulnerable to cognitive and behavioural difficulties and likely affect their quality of life (QoL). Our aim was to compare levels of cognition, psychosocial functioning, and health-related QoL of CC survivors to healthy controls and examine the associations between these three domains. Seventy-eight CC survivors (age range = 7-16 years, ≥ one year since cancer treatment) and 56 healthy controls were included. Cognition (i.e., fluid intelligence, executive functions, memory, processing speed, and selective attention), psychosocial functioning, and health-related QoL were assessed using standardized tests and questionnaires. The cognitive performance, parent-reported psychosocial behaviour, and health-related QoL of the CC survivors were within the normative range. However, working memory was significantly poorer in survivors than controls, and visuospatial working memory below the normative range was more commonly observed among survivors than among controls. Processing speed significantly predicted survivors' performance in executive functions. Among survivors, greater peer problems were significantly associated with poorer cognitive functions and health-related QoL. Despite the evidence for good intellectual functioning, which might point towards adequate reserves, in some survivors, domain-specific difficulties may emerge years after cancer relating to psychosocial development and QoL.

Effects of different types of classroom physical activity breaks on children's on-task behaviour, academic achievement and cognition.

AIM: This study examined the effects of different types of classroom physical activity breaks on children's on-task behaviour, academic achievement and cognition. METHODS: Participants were 87 Australian primary school students (mean age 9.11 ± 0.62 years), recruited from one school. Three classes were randomly assigned either to activity breaks only (n = 29), activity breaks and mathematics combined (n = 29), or control conditions involving only mathematical content (n = 29). Students were engaged in five minutes of classroom physical activity breaks, three times per week, for four weeks (divided into two minutes at the beginning of the usual mathematics curriculum lesson and three minutes in the middle of the lesson). Assessments were conducted at baseline and post-test. RESULTS: Significant group-by-time effects were found for on-task behaviour (active engagement: activity breaks and mathematics combined versus control, p ≤ 0.001; activity breaks versus control, p ≤ 0.001; activity breaks and mathematics combined versus activity breaks, p = 0.037; passive engagement: activity breaks and mathematics combined versus control, p ≤ 0.001) and mathematics scores (activity breaks versus control, p = 0.045). CONCLUSION: Physical activity breaks with and without integrated mathematics content were effective in improving children's on-task behaviour and learning scores.

Photobiomodulation Mediates Neuroprotection against Blue Light Induced Retinal Photoreceptor Degeneration.

Potent neuroprotective effects of photobiomodulation with 670 nm red light (RL) have been demonstrated in several models of retinal disease. RL improves mitochondrial metabolism, reduces retinal inflammation and oxidative cell stress, showing its ability to enhance visual function. However, the current knowledge is limited to the main hypothesis that the respiratory chain complex IV, cytochrome c oxidase, serves as the primary target of RL. Here, we demonstrate a comprehensive cellular, molecular, and functional characterization of neuroprotective effects of 670 nm RL and 810 nm near-infrared light (NIRL) on blue light damaged murine primary photoreceptors. We show that respiratory chain complexes I and II are additional PBM targets, besides complex IV, leading to enhanced mitochondrial energy metabolism. Accordingly, our study identified mitochondria related RL- and NIRL-triggered defense mechanisms promoting photoreceptor neuroprotection. The observed improvement of mitochondrial and extramitochondrial respiration in both inner and outer segments is linked with reduced oxidative stress including its cellular consequences and reduced mitochondria-induced apoptosis. Analysis of regulatory mechanisms using gene expression analysis identified upregulation α-crystallins that indicate enhanced production of proteins with protective functions that point to the rescued mitochondrial function. The results support the hypothesis that energy metabolism is a major target for retinal light therapy.

Correction to: The proliferation marker pKi-67 becomes masked to MIB-1 staining after expression of its tandem repeats.

In the PubMed citation records, the author's name shows.

The effect of exergaming on executive functions in children with ADHD: A randomized clinical trial.

BACKGROUND: Children with ADHD frequently suffer from deficits in cognitive (ie, executive functions) and motor abilities. Although medication usually has a positive effect, a lack of commitment and possible side effects result in a need for adjunct or alternative treatments. Thus, the aim of the current study was to investigate the effects of cognitively and physically demanding exergaming on executive functions, ADHD symptoms, and motor abilities. METHODS: In a parallel group randomized trial, 51 children between 8-12 years (M = 10.63; SD = 1.32) diagnosed with ADHD were assigned either to an 8-week exergame intervention group (three training sessions per week for 30 minutes) or a waiting-list control group. The core executive functions (inhibition, switching, updating), parent ratings of symptoms, and motor abilities were assessed/gathered before and after the intervention. RESULTS: Analyses of covariance (using pre-test values as covariates) revealed that children in the exergame intervention group improved in specific executive functions (reaction times in inhibition and switching), general psychopathology as well as motor abilities compared to control group. CONCLUSIONS: Findings indicate that exergaming might benefit two domains in which frequent deficits can be observed in children with ADHD, executive functions and motor abilities. Given that these beneficial effects in turn might positively affect psychopathology, exergaming could serve as an individualized home-based intervention in the future. However, in order to maximize benefits and make exergaming a valuable adjunct to treatment for children with ADHD, customized exergames are needed.

Neurodegeneration and Neuro-Regeneration-Alzheimer's Disease and Stem Cell Therapy.

Aging causes many changes in the human body, and is a high risk for various diseases. Dementia, a common age-related disease, is a clinical disorder triggered by neurodegeneration. Brain damage caused by neuronal death leads to cognitive decline, memory loss, learning inabilities and mood changes. Numerous disease conditions may cause dementia; however, the most common one is Alzheimer's disease (AD), a futile and yet untreatable illness. Adult neurogenesis carries the potential of brain self-repair by an endogenous formation of newly-born neurons in the adult brain; however it also declines with age. Strategies to improve the symptoms of aging and age-related diseases have included different means to stimulate neurogenesis, both pharmacologically and naturally. Finally, the regulatory mechanisms of stem cells neurogenesis or a functional integration of newborn neurons have been explored to provide the basis for grafted stem cell therapy. This review aims to provide an overview of AD pathology of different neural and glial cell types and summarizes current strategies of experimental stem cell treatments and their putative future use in clinical settings.

The Brainfit study: efficacy of cognitive training and exergaming in pediatric cancer survivors - a randomized controlled trial.

BACKGROUND: Cancer survival comes at a price: pediatric cancer survivors bear a high risk for a wide range of cognitive difficulties. Therefore, interventions targeting these difficulties are required. The aim of the present clinical trial is to extend empirical evidence about efficacy of cognitive and physical training in pediatric cancer survivors. It is hypothesized that early cognitive and physical interventions affect the remediation of pediatric cancer survivors in terms of improved executive functions (primary outcome). Additional positive effects of cognitive and physical intervention to other areas such as memory and attention are expected (secondary outcome). Changes in cognitive performance are expected to be associated with structural and functional changes in the brain. METHODS: Overall, 150 pediatric cancer survivors and 50 matched controls will be included in this trial. The cancer survivors will be randomly assigned to either a computerized cognitive training, a physical training (exergaming) or a waiting control group. They will be assessed with neuropsychological tests, tests of sport motor performance and physical fitness before and after 8 weeks of training and again at a 3-months follow-up. Moreover, neuroimaging will be performed at each of the three time points to investigate the training impact on brain structure and function. DISCUSSION: With increasing cancer survival rates, evidence-based interventions are of particular importance. New insights into training-related plasticity in the developing brain will further help to develop tailored rehabilitation programs for pediatric cancer survivors. TRIAL REGISTRATION: KEK BE 196/15; KEK ZH 2015-0397; ICTRP NCT02749877 ; date of registration: 30.11.2016; date of first participant enrolment: .18.01.2017.

Correction to: human periodontal ligament fibroblasts stimulated by nanocrystalline hydroxyapatite paste or enamel matrix derivative. An in vitro assessment of PDL attachment, migration, and proliferation.

In the original published version of this article, the middle name for author Mirko H. H. Schmidt is missing.

The Role of Microglia in Diabetic Retinopathy: Inflammation, Microvasculature Defects and Neurodegeneration.

Diabetic retinopathy is a common complication of diabetes mellitus, which appears in one third of all diabetic patients and is a prominent cause of vision loss. First discovered as a microvascular disease, intensive research in the field identified inflammation and neurodegeneration to be part of diabetic retinopathy. Microglia, the resident monocytes of the retina, are activated due to a complex interplay between the different cell types of the retina and diverse pathological pathways. The trigger for developing diabetic retinopathy is diabetes-induced hyperglycemia, accompanied by leukostasis and vascular leakages. Transcriptional changes in activated microglia, mediated via the nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and extracellular signal-regulated kinase (ERK) signaling pathways, results in release of various pro-inflammatory mediators, including cytokines, chemokines, caspases and glutamate. Activated microglia additionally increased proliferation and migration. Among other consequences, these changes in microglia severely affected retinal neurons, causing increased apoptosis and subsequent thinning of the nerve fiber layer, resulting in visual loss. New potential therapeutics need to interfere with these diabetic complications even before changes in the retina are diagnosed, to prevent neuronal apoptosis and blindness in patients.

Acetylation-dependent regulation of endothelial Notch signalling by the SIRT1 deacetylase.

Notch signalling is a key intercellular communication mechanism that is essential for cell specification and tissue patterning, and which coordinates critical steps of blood vessel growth. Although subtle alterations in Notch activity suffice to elicit profound differences in endothelial behaviour and blood vessel formation, little is known about the regulation and adaptation of endothelial Notch responses. Here we report that the NAD(+)-dependent deacetylase SIRT1 acts as an intrinsic negative modulator of Notch signalling in endothelial cells. We show that acetylation of the Notch1 intracellular domain (NICD) on conserved lysines controls the amplitude and duration of Notch responses by altering NICD protein turnover. SIRT1 associates with NICD and functions as a NICD deacetylase, which opposes the acetylation-induced NICD stabilization. Consequently, endothelial cells lacking SIRT1 activity are sensitized to Notch signalling, resulting in impaired growth, sprout elongation and enhanced Notch target gene expression in response to DLL4 stimulation, thereby promoting a non-sprouting, stalk-cell-like phenotype. In vivo, inactivation of Sirt1 in zebrafish and mice causes reduced vascular branching and density as a consequence of enhanced Notch signalling. Our findings identify reversible acetylation of the NICD as a molecular mechanism to adapt the dynamics of Notch signalling, and indicate that SIRT1 acts as rheostat to fine-tune endothelial Notch responses.

Cognitively and physically demanding exergaming to improve executive functions of children with attention deficit hyperactivity disorder: a randomised clinical trial.

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is one of the most common mental disorders observed in childhood and adolescence. Its key symptoms - reduced attention, poor control of impulses as well as increased motor activity - are associated with decreased executive functions performance, finally affecting academic achievement. Although drug treatments usually show some effect, alternative treatments are continually being sought, due to lack of commitment and possible side effects. Cognitive trainings are frequently used with the objectives of increasing executive function performance. However, since transfer effects are limited and novelty and diversity are frequently ignored, interventions combining physical and cognitive demands targeting a broader range of cognitive processes are demanded. METHODS: The aim of the study is to examine the effects of a cognitively and physically demanding exergame on executive functions of children with ADHD. In a randomised clinical trial, 66 girls and boys diagnosed with ADHD (age 8-12) will be assigned either to an 8-week exergame intervention group (three training sessions per week à 30 min) or a waiting-list control group. Before and afterwards, the executive function performance (computer-based tests), the sport motor performance and ADHD symptoms will be assessed. DISCUSSION: The current study will offer insights into the effectiveness of a combination of cognitive and physical training using exergaming. Positive effects on the executive functions, sport motor performance and ADHD symptoms are hypothesized. Beneficial effects would mean a large degree of scalability (simple and cost-effective) and high utility for patients with ADHD. TRIAL REGISTRATION: KEK BE 393/15 (March 8, 2016); DRKS00010171 (March 14, 2016).

EGFR and EGFRvIII Promote Angiogenesis and Cell Invasion in Glioblastoma: Combination Therapies for an Effective Treatment.

Epidermal growth factor receptor (EGFR) and the mutant EGFRvIII are major focal points in current concepts of targeted cancer therapy for glioblastoma multiforme (GBM), the most malignant primary brain tumor. The receptors participate in the key processes of tumor cell invasion and tumor-related angiogenesis and their upregulation correlates with the poor prognosis of glioma patients. Glioma cell invasion and increased angiogenesis share mechanisms of the degradation of the extracellular matrix (ECM) through upregulation of ECM-degrading proteases as well as the activation of aberrant signaling pathways. This review describes the role of EGFR and EGFRvIII in those mechanisms which might offer new combined therapeutic approaches targeting EGFR or EGFRvIII together with drug treatments against proteases of the ECM or downstream signaling to increase the inhibitory effects of mono-therapies.