Synaptonuclear messenger PRR7 inhibits c-Jun ubiquitination and regulates NMDA-mediated excitotoxicity.

Elevated c-Jun levels result in apoptosis and are evident in neurodegenerative disorders such as Alzheimer's disease and dementia and after global cerebral insults including stroke and epilepsy. NMDA receptor (NMDAR) antagonists block c-Jun upregulation and prevent neuronal cell death following excitotoxic insults. However, the molecular mechanisms regulating c-Jun abundance in neurons are poorly understood. Here, we show that the synaptic component Proline rich 7 (PRR7) accumulates in the nucleus of hippocampal neurons following NMDAR activity. We find that PRR7 inhibits the ubiquitination of c-Jun by E3 ligase SCF(FBW) (7) (FBW7), increases c-Jun-dependent transcriptional activity, and promotes neuronal death. Microarray assays show that PRR7 abundance is directly correlated with transcripts associated with cellular viability. Moreover, PRR7 knockdown attenuates NMDAR-mediated excitotoxicity in neuronal cultures in a c-Jun-dependent manner. Our results show that PRR7 links NMDAR activity to c-Jun function and provide new insights into the molecular processes that underlie NMDAR-dependent excitotoxicity.

Comparing synaptic proteomes across five mouse models for autism reveals converging molecular similarities including deficits in oxidative phosphorylation and Rho GTPase signaling.

Specific and effective treatments for autism spectrum disorder (ASD) are lacking due to a poor understanding of disease mechanisms. Here we test the idea that similarities between diverse ASD mouse models are caused by deficits in common molecular pathways at neuronal synapses. To do this, we leverage the availability of multiple genetic models of ASD that exhibit shared synaptic and behavioral deficits and use quantitative mass spectrometry with isobaric tandem mass tagging (TMT) to compare their hippocampal synaptic proteomes. Comparative analyses of mouse models for Fragile X syndrome (Fmr1 knockout), cortical dysplasia focal epilepsy syndrome (Cntnap2 knockout), PTEN hamartoma tumor syndrome (Pten haploinsufficiency), ANKS1B syndrome (Anks1b haploinsufficiency), and idiopathic autism (BTBR+) revealed several common altered cellular and molecular pathways at the synapse, including changes in oxidative phosphorylation, and Rho family small GTPase signaling. Functional validation of one of these aberrant pathways, Rac1 signaling, confirms that the ANKS1B model displays altered Rac1 activity counter to that observed in other models, as predicted by the bioinformatic analyses. Overall similarity analyses reveal clusters of synaptic profiles, which may form the basis for molecular subtypes that explain genetic heterogeneity in ASD despite a common clinical diagnosis. Our results suggest that ASD-linked susceptibility genes ultimately converge on common signaling pathways regulating synaptic function and propose that these points of convergence are key to understanding the pathogenesis of this disorder.

ANKS1B encoded AIDA-1 regulates social behaviors by controlling oligodendrocyte function.

Heterozygous deletions in the ANKS1B gene cause ANKS1B neurodevelopmental syndrome (ANDS), a rare genetic disease characterized by autism spectrum disorder (ASD), attention deficit/hyperactivity disorder, and speech and motor deficits. The ANKS1B gene encodes for AIDA-1, a protein that is enriched at neuronal synapses and regulates synaptic plasticity. Here we report an unexpected role for oligodendroglial deficits in ANDS pathophysiology. We show that Anks1b-deficient mouse models display deficits in oligodendrocyte maturation, myelination, and Rac1 function, and recapitulate white matter abnormalities observed in ANDS patients. Selective loss of Anks1b from the oligodendrocyte lineage, but not from neuronal populations, leads to deficits in social preference and sensory reactivity previously observed in a brain-wide Anks1b haploinsufficiency model. Furthermore, we find that clemastine, an antihistamine shown to increase oligodendrocyte precursor cell maturation and central nervous system myelination, rescues deficits in social preference in 7-month-old Anks1b-deficient mice. Our work shows that deficits in social behaviors present in ANDS may originate from abnormal Rac1 activity within oligodendrocytes.

Marine Microbiome as a Source of Antimalarials.

It is important to discover novel antimalarial pharmacophores because of the widespread emergence of Plasmodium falciparum isolates resistant to the available drugs. Secondary metabolites derived from microbes associated with marine invertebrates are a valuable resource for the discovery of novel drug leads. However, the potential of marine microbes as a source of antimalarials has not been explored. We investigated the promise of marine microorganisms for the production of antimalarial activities by testing 2365 diverse microbial extracts using phenotypic screening of a multidrug resistant chloroquine resistant P. falciparum strain. We conducted counter screening against mammalian cells for the 317 active extracts that exhibited more than 70% inhibition at 1 µg/mL. The screen identified 17 potent bioactive leads from a broad range of taxa. Our results establish that the marine microbiome is a rich source of antiplasmodial compounds that warrants in depth exploration.

Haploinsufficiency in the ANKS1B gene encoding AIDA-1 leads to a neurodevelopmental syndrome.

Neurodevelopmental disorders, including autism spectrum disorder, have complex polygenic etiologies. Single-gene mutations in patients can help define genetic factors and molecular mechanisms underlying neurodevelopmental disorders. Here we describe individuals with monogenic heterozygous microdeletions in ANKS1B, a predicted risk gene for autism and neuropsychiatric diseases. Affected individuals present with a spectrum of neurodevelopmental phenotypes, including autism, attention-deficit hyperactivity disorder, and speech and motor deficits. Neurons generated from patient-derived induced pluripotent stem cells demonstrate loss of the ANKS1B-encoded protein AIDA-1, a brain-specific protein highly enriched at neuronal synapses. A transgenic mouse model of Anks1b haploinsufficiency recapitulates a range of patient phenotypes, including social deficits, hyperactivity, and sensorimotor dysfunction. Identification of the AIDA-1 interactome using quantitative proteomics reveals protein networks involved in synaptic function and the etiology of neurodevelopmental disorders. Our findings formalize a link between the synaptic protein AIDA-1 and a rare, previously undefined genetic disease we term ANKS1B haploinsufficiency syndrome.