YWHAZ variation causes intellectual disability and global developmental delay with brain malformation.

YWHAZ encodes an adapter protein 14-3-3ζ, which is involved in many signaling pathways that control cellular proliferation, migration and differentiation. It has not been definitely correlated to any phenotype in OMIM. To investigate the role of YWHAZ gene in intellectual disability and global developmental delay, we conducted whole-exon sequencing in all of the available members from a large three-generation family and we discovered that a novel variant of the YWHAZ gene was associated with intellectual disability and global developmental delay. This variant is a missense mutation of YWHAZ, p.Lys49Asn/c.147A > T, which was found in all affected members but not found in other unaffected members. We also conducted computational modeling and knockdown/knockin with Drosophila to confirm the role of the YWHAZ variant in intellectual disability. Computational modeling showed that the binding energy was increased in the mutated protein combining with the ligand indicating that the c147A > T variation was a loss-of-function variant. Cognitive defects and mushroom body morphological abnormalities were observed in YWHAZ c.147A > T knockin flies. The YWHAZ knockdown flies also manifested serious cognitive defects with hyperactivity behaviors, which is consistent with the clinical features. Our clinical and experimental results consistently suggested that YWHAZ was a novel intellectual disability pathogenic gene.

Ketone Body Rescued Seizure Behavior of LRP1 Deficiency in Drosophila by Modulating Glutamate Transport.

LRP1, the low-density lipoprotein receptor 1, would be a novel candidate gene of epilepsy according to our bioinformatic results and the animal study. In this study, we explored the role of LRP1 in epilepsy and whether beta-hydroxybutyrate, the principal ketone body of the ketogenic diet, can treat epilepsy caused by LRP1 deficiency in drosophila. UAS/GAL4 system was used to establish different genotype models. Flies were given standard, high-sucrose, and ketone body food randomly. The bang-sensitive test was performed on flies and seizure-like behavior was assessed. In morphologic experiments, we found that LRP1 deficiency caused partial loss of the ellipsoidal body and partial destruction of the fan-shaped body. Whole-body and glia LRP1 defect flies had a higher seizure rate compared to the control group. Ketone body decreased the seizure rate in behavior test in all LRP1 defect flies, compared to standard and high sucrose diet. Overexpression of glutamate transporter gene Eaat1 could mimic the ketone body effect on LRP1 deficiency flies. This study demonstrated that LRP1 defect globally or in glial cells or neurons could induce epilepsy in drosophila. The ketone body efficaciously rescued epilepsy caused by LRP1 knockdown. The results support screening for LRP1 mutations as discriminating conduct for individuals who require clinical attention and further clarify the mechanism of the ketogenic diet in epilepsy, which could help epilepsy patients make a precise treatment case by case.

Effects of Deferasirox in Alzheimer's Disease and Tauopathy Animal Models.

The accumulation of iron may contribute to Alzheimer's disease (AD) and other tauopathies. The iron chelator desferrioxamine slows disease progression in AD patients. However, desferrioxamine requires injection, which is inconvenient and may hinder compliance. We therefore tested an oral iron chelator, desferasirox (Exjade), in transgenic animal models. Tg2576 mice overexpress the mutant human APP protein and produce the Aß peptide. JNPL3 mice (Tau/Tau) overexpress the mutant human tau protein. Crossing these produced APP/Tau mice, overexpressing both APP and tau. Treating the three models with 1.6 mg deferasirox thrice weekly from age 8 to 14 months did not affect memory as measured by contextual fear conditioning or motor function as measured by rotarod, but tended to decrease hyperphosphorylated tau as measured by AT8 immunohistochemistry and immunoblotting. Deferasirox might act by decreasing iron, which aggregates tau, or directly binding tau to inhibit aggregation.

Rationale for the development of an Alzheimer's disease vaccine.

Vaccination traditionally has targeted infectious agents and thus has not heretofore been used to prevent neurodegenerative illness. However, amyloid ß (Aß) or tau, which can act like infectious proteins, or prions, might induce Alzheimer's disease (AD). Furthermore, evidence suggests that traditional infectious agents, including certain viruses and bacteria, may trigger AD. It is therefore worth exploring whether removing such targets could prevent AD. Although failing to treat AD patients who already display cognitive impairment, Aß monoclonal antibodies are being tested in pre-symptomatic, at-risk individuals to prevent dementia. These antibodies might become the first AD therapeutics. However, their high cost will keep them out of the arms of the vast majority of patients, who increasingly live in developing countries. Because vaccines produce antibodies internally at much lower cost, vaccination might be the most promising approach to reducing the global burden of dementia.

The sympathetic nervous system regulates skeletal muscle motor innervation and acetylcholine receptor stability.

AIM: Symptoms of autonomic failure are frequently the presentation of advanced age and neurodegenerative diseases that impair adaptation to common physiologic stressors. The aim of this work was to examine the interaction between the sympathetic and motor nervous system, the involvement of the sympathetic nervous system (SNS) in neuromuscular junction (NMJ) presynaptic motor function, the stability of postsynaptic molecular organization, and the skeletal muscle composition and function. METHODS: Since muscle weakness is a symptom of diseases characterized by autonomic dysfunction, we studied the impact of regional sympathetic ablation on muscle motor innervation by using transcriptome analysis, retrograde tracing of the sympathetic outflow to the skeletal muscle, confocal and electron microscopy, NMJ transmission by electrophysiological methods, protein analysis, and state of the art microsurgical techniques, in C57BL6, MuRF1KO and Thy-1 mice. RESULTS: We found that the SNS regulates motor nerve synaptic vesicle release, skeletal muscle transcriptome, muscle force generated by motor nerve activity, axonal neurofilament phosphorylation, myelin thickness, and myofibre subtype composition and CSA. The SNS also modulates the levels of postsynaptic membrane acetylcholine receptor by regulating the Gαi2 -Hdac4-Myogenin-MuRF1pathway, which is prevented by the overexpression of the guanine nucleotide-binding protein Gαi2 (Q205L), a constitutively active mutant G protein subunit. CONCLUSION: The SNS regulates NMJ transmission, maintains optimal Gαi2 expression, and prevents any increase in Hdac4, myogenin, MuRF1, and miR-206. SNS ablation leads to upregulation of MuRF1, muscle atrophy, and downregulation of postsynaptic AChR. Our findings are relevant to clinical conditions characterized by progressive decline of sympathetic innervation, such as neurodegenerative diseases and aging.

Effects of Resveratrol and Morin on Insoluble Tau in Tau Transgenic Mice.

Tauopathies are neurodegenerative diseases, including Alzheimer's disease (AD) and frontotemporal dementia (FTD), in which tau protein aggregates within neurons. An effective treatment is lacking and is urgently needed. We evaluated two structurally similar natural compounds, morin and resveratrol, for treating tauopathy in JNPL3 P301L mutant human tau overexpressing mice. Rotarod tests were performed to determine effects on motor function. After treatment from age 11 to 14 months, brains of 26 mice were collected to quantify aggregated hyperphosphorylated tau by Thioflavin T and immunohistochemistry (IHC) and to quantify total tau (HT7 antibody) and hyperphosphorylated tau (AT8 antibody) in homogenates and a fraction enriched for paired helical filaments. Resveratrol reduced the level of total hyperphosphorylated tau in IHC sections (p=0.036), and morin exhibited a tendency to do so (p=0.29), while the two drugs tended to increase the proportion of solubilizable tau that was hyperphosphorylated, as detected in blots. Neither resveratrol nor morin affected motor function. One explanation of these results is that the drugs might interrupt a late stage in tau aggregation, after small aggregates have formed but before further aggregation has occurred. Further animal studies would be informative to explore the possible efficacy of morin or resveratrol for treating tauopathies.

Osteoporosis: from osteoscience to neuroscience and beyond.

Osteoporosis is well known to be a poly-factorial skeletal disorder characterized by a low bone mineral density (BMD) at which the risk of developing fracture is remarkably increased and affecting both the quality and quantity of life. Although it is nearly 180 years, since its first pathological identification, there is no effective cure against such aging-associated health concern. Traditional research direction on osteoporosis was mainly focused on the balance between bone formation and resorption, in which osteoblast and osteoclast physiology as well as a variety of relevant molecular factors underlying bone homeostasis have been intensively studied. Due to the knowledge advances in the field, more potential candidate factors/target genes involved in the regulation of bone homeostasis have been identified. Representative examples included the new roles of osteocytes in bone homeostasis and endocrine functions. Additionally, the muscular and nervous system also seem to play a regulatory role in bone homeostasis. After all, these new findings have paved novel directions in osteoporosis research. This review is aimed to provide an overview on the current accepted concepts of osteoporosis-associated bone physiology and its potential research directions in the near future.

Sarcopenia: the gliogenic perspective.

It has been approximately 25 years since Dr. Rosenberg first brought attention to sarcopenia. To date, this aging-associated condition is recognized as a chronic loss of muscle mass and is usually accompanied by dynapenia. Despite its poly-etiological factors, sarcopenia has a strong neurogenic component underlying this chrono-degeneration of muscle mass, as shown in recent studies. As it seems plausible to explain the origin of sarcopenia through a motor neuron degeneration model, the focus of sarcopenia research should combine neuroscience with the study of the original myocyte and satellite cells. Although a complete mechanism underlying the development of sarcopenia has yet to be elucidated, we propose that the primary trigger of sarcopenia could be gliogenic in origin based on the close relationship between the glia, neurons and non-neural cells, for example, the motor unit and its associated glia in both the central nervous system (CNS) and the peripheral nervous system (PNS). In addition to muscle cells, both of the neural cells are affected by aging.

Sarcopenia, a neurogenic syndrome?

Sarcopenia is an aging-associated condition, which is currently characterized by the loss of muscle mass and muscle strength. However, there is no consensus regarding its characterization hitherto. As the world older adult population is on the rise, the impact of sarcopenia becomes greater. Due to the lack of effective treatments, sarcopenia is still a persisting problem among the global older adults and should not be overlooked. As a result, it is vital to investigate deeper into the mechanism underlying the pathogenesis of sarcopenia in order to develop more effective therapeutic interventions and to inscribe a more uniform characterization. The etiology of sarcopenia is currently found to be multifactorial, and most of the pharmacological researches are focused on the muscular factors in aging. Although the complete mechanism underlying the development of sarcopenia is still waiting to be elucidated, we propose in this article that the primary trigger of sarcopenia may be neurogenic in origin based on the intimate relationship between the nervous and muscular system, namely, the motor neuron and its underlying muscle fibers. Both of them are affected by the cellular environment and their physiological activity.

Assessing the cluster glycoside effect during the binding of concanavalin A to mannosylated artificial lipid rafts.

Mannosyl glycolipids with perfluoroalkyl membrane anchors have been synthesised. When inserted into vesicles, these mannosyl lipids either dispersed evenly over the surface or, in the presence of cholesterol, phase-separated into artificial lipid rafts. At 1% mol/mol, the affinity of dispersed mannosyl lipids for Con A was 3-fold weaker than in solution, perhaps reflecting steric blocking by the surface. However increasing membrane loading 5-fold increased Con A affinity by up to 75% and indicated weak intramembrane chelation of Con A. Despite this observation, concentrating the mannosyl lipids into artificial lipid rafts did not significantly improve affinity for Con A. This lack of a cluster glycoside effect was ascribed to lipid congestion inhibiting intra-raft chelation of Con A, and implies that glycolipids located in lipid rafts may not necessarily be preorganised for multivalent binding.

Creating functional vesicle assemblies from vesicles and nanoparticles.

Vesicles (liposomes) have been shown to be excellent vehicles for drug delivery, yet assemblies of vesicles (vesicle aggregates) have been used infrequently in this context. However vesicle assemblies have useful properties not available to individual vesicles; their size can cause localisation in specific tissues and they can incorporate more functionality than is possible with individual vesicles. This article reviews progress on controlling the properties of vesicle assemblies in vitro, applications of vesicle assemblies in vivo, and our recent creation of magnetic nanoparticle-vesicle assemblies. The latter assemblies contain vesicles crosslinked by coated Fe3O4 nanoparticles and this inclusion of magnetic functionality makes them magnetically responsive, potentially allowing magnetically-induced contents release. This article describes further studies on the in vitro formation of these magnetic nanoparticle-vesicle assemblies, including the effect of changing magnetic nanoparticle concentration, pH, adhesive lipid structure and bilayer composition. These investigations have led to the development of thermally-sensitive magnetic nanoparticle-vesicle assemblies that release encapsulated methotrexate on warming.

Magnetically-controlled release from hydrogel-supported vesicle assemblies.

Magnetic nanoparticle-vesicle assemblies embedded within a hydrogel extravesicular matrix have been shown to release their contents in response to a remote magnetic trigger.

The effect of receptor clustering on vesicle-vesicle adhesion.

As part of our studies into how the localization of cell adhesion molecules into lipid rafts may affect cell adhesion, we developed Cu(1), a synthetic copper(iminodiacetate)-capped receptor able to phase separate from fluid phospholipid bilayers. The extent to which Cu(1) clustered into adhesive patches on the surface of vesicles could be controlled by changing vesicle composition. Extensive receptor phase separation significantly enhanced vesicle-vesicle adhesion; only vesicles with adhesive patches (blue fluorescence) adhered to their conjugate histidine-coated vesicles (red fluorescence) to form large vesicle aggregates (shown).