The Postsynaptic Density Proteins Homer and Shank Form a Polymeric Network Structure

The postsynaptic density (PSD) is crucial for synaptic functions, but the molecular architecture retaining its structure and components remains elusive. Homer and Shank are among the most abundant scaffolding proteins in the PSD, working synergistically for maturation of dendritic spines. Here, we demonstrate that Homer and Shank, together, form a mesh-like matrix structure. Crystallographic analysis of this region revealed a pair of parallel dimeric coiled coils intercalated in a tail-to-tail fashion to form a tetramer, giving rise to the unique configuration of a pair of N-terminal EVH1 domains at each end of the coiled coil. In neurons, the tetramerization is required for structural integrity of the dendritic spines and recruitment of proteins to synapses. We propose that the Homer-Shank complex serves as a structural framework and as an assembly platform for other PSD proteins.Massachusetts Institute of Technology. Biophysical Instrumentation FacilityRIKEN Brain Science InstituteNational Institutes of Health (U.S.) (Grant R01DA17310)Japan. Ministry of Education, Culture, Sports, Science and Technology (Grant-in-Aid for Scientific Research

Definition and clinical variability of SHANK3-related Phelan-McDermid syndrome

Phelan-McDermid syndrome (PMS) is an infrequently described syndrome that presents with a disturbed development, neurological and psychiatric characteristics, and sometimes other comorbidities. As part of the development of European medical guidelines we studied the definition, phenotype, genotype-phenotype characteristics, and natural history of the syndrome. The number of confirmed diagnoses of PMS in different European countries was also assessed and it could be concluded that PMS is underdiagnosed. The incidence of PMS in European countries is estimated to be at least 1 in 30,000. Next generation sequencing, including analysis of copy number variations, as first tier in diagnostics of individuals with intellectual disability will likely yield a larger number of individuals with PMS than presently known. A definition of PMS by its phenotype is at the present not possible, and therefore PMS-SHANK3 related is defined by the presence of SHANK3 haploinsufficiency, either by a deletion involving region 22q13.2–33 or a pathogenic/likely pathogenic variant in SHANK3. In summarizing the phenotype, we subdivided it into that of individuals with a 22q13 deletion and that of those with a pathogenic/likely pathogenic SHANK3 variant. The phenotype of individuals with PMS is variable, depending in part on the deletion size or whether only a variant of SHANK3 is present. The core phenotype in the domains development, neurology, and senses are similar in those with deletions and SHANK3 variants, but individuals with a SHANK3 variant more often are reported to have behavioural disorders and less often urogenital malformations and lymphedema. The behavioural disorders may, however, be a less outstanding feature in individuals with deletions accompanied by more severe intellectual disability. Data available on the natural history are limited. Results of clinical trials using IGF-1, intranasal insulin, and oxytocin are available, other trials are in progress. The present guidelines for PMS aim at offering tools to caregivers and families to provide optimal care to individuals with PMS.</p

The X-linked intellectual disability protein IL1RAPL1 regulates excitatory synapse formation by binding PTPδ and RhoGAP2

Mutations of the Interleukin-1-receptor accessory protein like 1 (IL1RAPL1) gene are associated with cognitive impairment ranging from non-syndromic X-linked mental retardation to autism. IL1RAPL1 belongs to a novel family of IL1/Toll receptors, which is localized at excitatory synapses and interacts with PSD-95. We previously showed that IL1RAPL1 regulates the synaptic localization of PSD-95 by controlling c-Jun N-terminal kinase activity and PSD-95 phosphorylation. Here, we show that the IgG-like extracellular domains of IL1RAPL1 induce excitatory pre-synapse formation by interacting with protein tyrosine phosphatase delta (PTPδ). We also found that IL1RAPL1 TIR domains interact with RhoGAP2, which is localized at the excitatory post-synaptic density. More interestingly, the IL1RAPL1/PTPδ complex recruits RhoGAP2 at excitatory synapses to induce dendritic spine formation. We also found that the IL1RAPL1 paralog, IL1RAPL2, interacts with PTPδ and induces excitatory synapse and dendritic spine formation. The interaction of the IL1RAPL1 family of proteins with PTPδ and RhoGAP2 reveals a pathophysiological mechanism of cognitive impairment associated with a novel type of trans-synaptic signaling that regulates excitatory synapse and dendritic spine formation

Recommendations, guidelines, and best practice for the use of human induced pluripotent stem cells for neuropharmacological studies of neuropsychiatric disorders

The number of individuals suffering from neuropsychiatric disorders (NPDs) has increased worldwide, with 3 million disability-adjusted life-years calculated in 2019. Though research using various approaches including genetics, imaging, clinical and animal models has advanced our knowledge regarding NPDs, we still lack basic knowledge regarding the underlying pathophysiological mechanisms. Moreover, there is an urgent need for highly effective therapeutics for NPDs. Human induced pluripotent stem cells (hiPSCs) generated from somatic cells enabled scientists to create brain cells in a patient-specific manner. However, there are challenges to the use of hiPSCs that need to be addressed. In the current paper, consideration of best practices for neuropharmacological and neuropsychiatric research using hiPSCs will be discussed. Specifically, we provide recommendations for best practice in patient recruitment, including collecting demographic, clinical, medical (before and after treatment and response), diagnostic (including scales) and genetic data from the donors. We highlight considerations regarding donor genetics and sex, in addition to discussing biological and technical replicates. Furthermore, we present our views on selecting control groups/lines, experimental designs, and considerations for conducting neuropharmacological studies using hiPSC-based models in the context of NPDs. In doing so, we explore key issues in the field concerning reproducibility, statistical analysis, and how to translate in vitro studies into clinically relevant observations. The aim of this article is to provide a key resource for hiPSC researchers to perform robust and reproducible neuropharmacological studies, with the ultimate aim of improving identification and clinical translation of novel therapeutic drugs for NPDs

Anti-Angiogenic Therapy Induces Integrin-Linked Kinase 1 Up-Regulation in a Mouse Model of Glioblastoma

BACKGROUND: In order to improve our understanding of the molecular pathways that mediate tumor proliferation and angiogenesis, and to evaluate the biological response to anti-angiogenic therapy, we analyzed the changes in the protein profile of glioblastoma in response to treatment with recombinant human Platelet Factor 4-DLR mutated protein (PF4-DLR), an inhibitor of angiogenesis. METHODOLOGY/PRINCIPAL FINDINGS: U87-derived experimental glioblastomas were grown in the brain of xenografted nude mice, treated with PF4-DLR, and processed for proteomic analysis. More than fifty proteins were differentially expressed in response to PF4-DLR treatment. Among them, integrin-linked kinase 1 (ILK1) signaling pathway was first down-regulated but then up-regulated after treatment for prolonged period. The activity of PF4-DLR can be increased by simultaneously treating mice orthotopically implanted with glioblastomas, with ILK1-specific siRNA. As ILK1 is related to malignant progression and a poor prognosis in various types of tumors, we measured ILK1 expression in human glioblastomas, astrocytomas and oligodendrogliomas, and found that it varied widely; however, a high level of ILK1 expression was correlated to a poor prognosis. CONCLUSIONS/SIGNIFICANCE: Our results suggest that identifying the molecular pathways induced by anti-angiogenic therapies may help the development of combinatorial treatment strategies that increase the therapeutic efficacy of angiogenesis inhibitors by association with specific agents that disrupt signaling in tumor cells

Recommendations, guidelines, and best practice for the use of human induced pluripotent stem cells for neuropharmacological studies of neuropsychiatric disorders

The number of individuals suffering from neuropsychiatric disorders (NPDs) has increased worldwide, with 3 million disability-adjusted life-years calculated in 2019. Though research using various approaches including genetics, imaging, clinical and animal models has advanced our knowledge regarding NPDs, we still lack basic knowledge regarding the underlying pathophysiological mechanisms. Moreover, there is an urgent need for highly effective therapeutics for NPDs i. Human induced pluripotent stem cells (hiPSCs) generated from somatic cells enabled scientists to create brain cells in a patient-specific manner. However, there are challenges to the use of hiPSCs that need to be addressed. In the current paper, consideration of best practices for neuropharmacological and neuropsychiatric research using hiPSCs will be discussed. Specifically, we provide recommendations for best practice in patient recruitment, including collecting demographic, clinical, medical (before and after treatment and response), diagnostic (incl. scales) and genetic data from the donors. We highlight considerations regarding donor genetics and sex, in addition to discussing biological and technical replicates. Furthermore, we present our views on selecting control groups/lines, experimental designs, and considerations for conducting neuropharmacological studies using hiPSC-based models in the context of NPDs. In doing so, we explore key issues in the field concerning reproducibility, statistical analysis, and how to translate in vitro studies into clinically relevant observations. The aim of this article is to provide a key resource for hiPSC researchers to perform robust and reproducible neuropharmacological studies, with the ultimate aim of improving identification and clinical translation of novel therapeutic drugs for NPDs

Proteomic characterization of the antiangiogenic activity of PF4-DLR in glioblastomas

non disponibileThe prognosis of the most common glial tumors, the glioblastoma (GBM; World Health Organization grade IV), remains poor with 2-year survival rates at less than 20% despite significant advances in therapeutic options available to patients. The dependence of tumor growth and metastasis on angiogenesis has provided powerful rationale for anti-angiogenic approaches to cancer therapy (Folkman J. 1971; Carmeliet P. et al. 2000). One of the most important negative regulators of angiogenesis is platelet factor-4 (PF-4). In a previous study Hagedorn M. et al. demonstrated that PF4-DLR inhibits tumor growth in an intracranial glioma model. In this study we use a proteomic approach to better understand the molecular mechanisms involved in PF4-DLR response. Experiments were performed on gliomas treated for 10 and 20 days with PF4-DLR. Two\u2013dimensional SDSpolyacrylamide gel elecrophoresis technique (2D-SDS-PAGE) was use to compare protein expression pattern between treated and untreated tumors. In tumors treated with PF4-DLR for 10 days we identified 24 proteins that were differentially expressed (p<0.05) in response to the treatment. In mice treated with PF4-DLR for 20 days we identified 30 proteins to be differentially expressed (p<0.05) subsequently to the treatment. A bioinformatics analysis of the identified proteins revealed the complexity of the pathway modulated by PF4-DLR treatment and suggest that two different protein populations is regulated by the treatment: one involved in growth inhibition mediated by PF4-DLR and one involved in tumor escape. Most of the proteins we have identified at 20 days of treatment seem to be functionally involved in regulating tumor growth and escape. Interestingly we detected in tumors from animals treated with PF4-DLR for 10 days a significant decrease of ILK levels compared with untreated tumors while in mice treated with PF4-DLR for 20 days we detected a significant increase of ILK levels compared with untreated tumors. We also analyzed the ILK levels in human low grade gliomas compared with human high grade gliomas. We found a significant increase of ILK in high grade gliomas compared to low grade. Consequently ILK can represent a new molecular target for gliomas therapy. Thus, as first approach, we have identified specific ILK siRNA that are able to reduce glioma cell proliferation. Our data taken together indicate that the combinatorial administration of compounds that simultaneously inhibit angiogenesis and tumor cell proliferation by targeting specific signaling pathways might results in a significant increase in the therapeutic efficacy

Molecular basis for prospective pharmacological treatment strategies in intellectual disability syndromes

A number of mutated genes that code for proteins concerned with brain synapse function and circuit formation have been identified in patients affected by intellectual disability syndromes over the last fifteen years. These genes are functionally involved in synapse formation and plasticity, the regulation of dendritic spine morphology, the regulation of the synaptic cytoskeleton, the synthesis and degradation of specific synapse proteins and the control of correct balance between excitatory and inhibitory synapses. In most of the cases even mild alterations in synapse morphology, function and balance give rise to mild or severe intellectual disabilities. These studies provided the rationale for the development of pharmacological agents that are able to counteract functional synaptic anomalies and potentially improve the symptoms of some of these conditions. This review summarizes recent findings on the functions of some of the genes responsible for intellectual disability syndromes and some of the new potential pharmacological treatments for these diseases