Classification and molecular pathogenesis of NBIA syndromes

Brain iron accumulation is the hallmark of a group of seriously invalidating and progressive rare diseases collectively denominated Neurodegeneration with Brain Iron Accumulation (NBIA), characterized by movement disorder, painful dystonia, parkinsonism, mental disability and early death. Currently there is no established therapy available to slow down or reverse the progression of these conditions. Several genes have been identified as responsible for NBIA but only two encode for proteins playing a direct role in iron metabolism. The other genes encode for proteins either with various functions in lipid metabolism, lysosomal activity and autophagic processes or with still unknown roles. The different NBIA subtypes have been classified and denominated on the basis of the mutated genes and, despite genetic heterogeneity, some of them code for proteins, which share or converge on common metabolic pathways. In the last ten years, the implementation of genetic screening based on Whole Exome Sequencing has greatly accelerated gene discovery, nevertheless our knowledge of the pathogenic mechanisms underlying the NBIA syndromes is still largely incomplete.     

Functional assessment tools in children with Pompe disease: A pilot comparative study to identify suitable outcome measures for the standard of care

Background

Pompe disease (PD) is a rare condition caused by mutations in gene encoding for the enzyme alpha-glucosidase, resulting in an abnormal intracellular accumulation of glycogen. The disease clinical spectrum ranges from severe infantile forms to adult-onset forms with minor limitations. Since 2000 enzyme replacement therapy (ERT) is available and disease natural history has changed, with prolonged survival and evidence of myopathic features.

Leptin upregulates aquaporin 9 expression in human placenta in vitro

Aquaporins are integral membrane proteins that have permeability functions in many tissues. Aquaporin 9 may transport not only water but also small molecules, such as glycerol, monocarboxylates, purines and pyrimidines. Aquaporin 9 is expressed in syncytiotrophoblast of human term placenta, and it may contribute to the embryonic/fetal growth and survival. We have previously found that Aquaporin 9 expression levels seem to be increased in placenta from gestational diabetes. Since leptin plasma levels and leptin expression are increased in placenta from gestational diabetes, we aimed to study the possible role of leptin on Aquaporin 9 expression in human placenta in vitro. The present work shows that leptin produces a dose-dependent increase of Aquaporin 9 expression, resulting in an increase in Aquaporin-9 protein in human trophoblast explants.     

A Bayesian predictive two-stage design for phase II clinical trials

In this paper, we propose a Bayesian two-stage design for phase II clinical trials, which represents a predictive version of the single threshold design (STD) recently introduced by Tan and Machin. The STD two-stage sample sizes are determined specifying a minimum threshold for the posterior probability that the true response rate exceeds a pre-specified target value and assuming that the observed response rate is slightly higher than the target. Unlike the STD, we do not refer to a fixed experimental outcome, but take into account the uncertainty about future data. In both stages, the design aims to control the probability of getting a large posterior probability that the true response rate exceeds the target value. Such a probability is expressed in terms of prior predictive distributions of the data. The performance of the design is based on the distinction between analysis and design priors, recently introduced in the literature. The properties of the method are studied when all the design parameters vary.     

Investigation of Autism Spectrum Disorder and Autistic Traits in an Adolescent Sample with Anorexia Nervosa

This study aimed to examine the presence of Autism Spectrum Disorder (ASD) in a sample of female adolescents with Anorexia Nervosa (AN) during the acute phase of illness. We also compare the level of autistic traits, social perception skills and obsessive–compulsive symptoms in four groups: AN, ASD, and two gender- and age-matched control groups. Of the 30 AN participants, only three scored above the conventional ADOS-2 threshold for ASD. The AN participants were similar to their controls on autistic trait measures, and to the ASD group on obsessive–compulsive measures, and on theory of mind ability and affect recognition measures. Further longitudinal studies are needed in order to determine the association between these conditions.     

Intermittent theta‐burst stimulation rescues dopamine‐dependent corticostriatal synaptic plasticity and motor behavior in experimental parkinsonism: Possible role of glial activity

Background : Recent studies support the therapeutic utility of repetitive transcranial magnetic stimulation in Parkinson's disease (PD), whose progression is correlated with loss of corticostriatal long‐term potentiation and long‐term depression. Glial cell activation is also a feature of PD that is gaining increasing attention in the field because astrocytes play a role in chronic neuroinflammatory responses but are also able to manage dopamine (DA) levels. Methods : Intermittent theta‐burst stimulation protocol was applied to study the effect of therapeutic neuromodulation on striatal DA levels measured by means of in vivo microdialysis in 6‐hydroxydopamine‐hemilesioned rats. Effects on corticostriatal synaptic plasticity were studied through in vitro intracellular and whole‐cell patch clamp recordings while stepping test and CatWalk were used to test motor behavior. Immunohistochemical analyses were performed to analyze morphological changes in neurons and glial cells. Results : Acute theta‐burst stimulation induced an increase in striatal DA levels in hemiparkinsonian rats, 80 minutes post‐treatment, correlated with full recovery of plasticity and amelioration of motor performances. With the same timing, immediate early gene activation was restricted to striatal spiny neurons. Intense astrocytic and microglial responses were also significantly reduced 80 minutes following theta‐burst stimulation. Conclusion : Taken together, these results provide a first glimpse on physiological adaptations that occur in the parkinsonian striatum following intermittent theta‐burst stimulation and may help to disclose the real potential of this technique in treating PD and preventing DA replacement therapy‐associated disturbances. © 2017 International Parkinson and Movement Disorder Society     

Cannabinoids prevent the amyloid β‐induced activation of astroglial hemichannels: A neuroprotective mechanism

The mechanisms involved in Alzheimer's disease are not completely understood and how astrocytes and their gliotransmission contribute to this neurodegenerative disease remains to be fully elucidated. Previous studies have shown that amyloid‐β peptide (Aβ) induces neuronal death by a mechanism that involves the excitotoxic release of ATP and glutamate associated to astroglial hemichannel opening. We have demonstrated that synthetic and endogenous cannabinoids (CBs) reduce the opening of astrocyte Cx43 hemichannels evoked by activated microglia or inflammatory mediators. Nevertheless, whether CBs could prevent the astroglial hemichannel‐dependent death of neurons evoked by Aβ is unknown. Astrocytes as well as acute hippocampal slices were treated with the active fragment of Aβ alone or in combination with the following CBs: WIN, 2‐AG, or methanandamide (Meth). Hemichannel activity was monitored by single channel recordings and by time‐lapse ethidium uptake while neuronal death was assessed by Fluoro‐Jade C staining. We report that CBs fully prevented the hemichannel activity and inflammatory profile evoked by Aβ in astrocytes. Moreover, CBs fully abolished the Aβ‐induced release of excitotoxic glutamate and ATP associated to astrocyte Cx43 hemichannel activity, as well as neuronal damage in hippocampal slices exposed to Aβ. Consequently, this work opens novel avenues for alternative treatments that target astrocytes to maintain neuronal function and survival during AD. GLIA 2016 GLIA 2017;65:122–137     

Activity-based photoacoustic probe for biopsy-free assessment of copper in murine models of Wilson’s disease and liver metastasis

The development of high-performance photoacoustic (PA) probes that can monitor disease biomarkers in deep tissue has the potential to replace invasive medical procedures such as a biopsy. However, such probes must be optimized for in vivo performance and exhibit an exceptional safety profile. In this study, we have developed PACu-1, a PA probe designed for biopsy-free assessment (BFA) of hepatic Cu via photoacoustic imaging. PACu-1 features a Cu(I)-responsive trigger appended to an aza-BODIPY dye platform that has been optimized for ratiometric sensing. Owing to its excellent performance, we were able to detect basal levels of Cu in healthy wild-type mice as well as elevated Cu in a Wilson’s disease model and in a liver metastasis model. To showcase the potential impact of PACu-1 for BFA, we conducted two blind studies in which we were able to successfully identify Wilson’s disease animals from healthy control mice in each instance.

Photoacoustic (PA) imaging is a light-in, sound-out technique that has emerged as a promising biomedical approach for the noninvasive assessment of various ailments in humans, ranging from arthritis to cancer (1, 2). Excitation of an endogenous pigment such as hemoglobin in blood or melanin in tissue can provide contrast, since relaxation via nonradiative decay can trigger thermoelastic expansion of the surrounding tissue. Repeatedly irradiating a region of interest with a pulsed laser can result in pressure waves that can be readily detected by ultrasound transducers. Since ultrasound at clinically relevant frequencies can travel through the body with minimal perturbation, it is possible to accurately pinpoint the source of the signal to afford high-resolution images at centimeter imaging depths (3). Beyond label-free applications, the utility of PA imaging for disease detection has been augmented by the recent development of acoustogenic probes (activatable PA probes) that give an off-on signal enhancement or ratiometric readout (4, 5). Such examples, as well as imaging agents for other modalities, are designed based on the principles of activity-based sensing, which leverages the chemical reactivity of an analyte to probe and manipulate the system under investigation (6–8). Notable acoustogenic molecules include those that can visualize dysregulated enzymatic activities (9–12), properties of the disease tissue microenvironment (13–15), as well as small molecule– and metal ion–based disease biomarkers (16–24). However, replacing an invasive medical procedure, such as a liver biopsy, with an acoustogenic probe is an immense challenge, since the in vivo performance and safety profile of such a chemical tool must be exceptional. Thus, despite undesirable shortcomings, such as the potential to develop severe infections, false negatives due to collection of nondiseased tissue, and the inability to directly monitor disease progression in real time (25), liver biopsies are still commonly employed to assess biomarkers in conditions such as Wilson’s disease (WD) (26) and cancer (27).It is noteworthy that elevated levels of hepatic copper (Cu) are a common biomarker shared by these conditions. In WD, Cu accumulates in the liver due to a genetic mutation in the Cu exporter, ATP7B, and this can lead to chronic liver damage, which can become fatal if not treated (28, 29). In the context of cancer, Cu is elevated in many solid tumors including breast (30, 31) and lung (32, 33) cancers, which generally metastasize to the liver. Since Cu can promote angiogenesis and drive tumor progression, biopsy-free assessment (BFA) of Cu in metastatic lesions is critical. A number of Cu probes exists for various modalities (34, 35), including examples compatible with in vivo applications via fluorescent (36) and bioluminescent (37) imaging. However, approaches that involve the emission of photons are more suitable for shallow imaging depths (millimeter range) owing to scattering and attenuation of light. More recently, our group (16, 38) and others (39) have developed Cu probes for PA imaging to achieve greater tissue penetration and higher resolution. However, these probes are designed to target Cu(II), whereas intracellular Cu exists predominantly in the +1 form owing to the highly reducing environment of the cell (40). To overcome this challenge, we present the development of PACu-1, an acoustogenic probe for Cu(I), and its application in BFA of hepatic Cu in a WD model and a liver metastasis model. Moreover, we designed two unbiased BFA blind studies to identify WD mice from healthy wild-type (WT) controls using PACu-1.