Exosomes regulate neurogenesis and circuit assembly.

Exosomes are thought to be released by all cells in the body and to be involved in intercellular communication. We tested whether neural exosomes can regulate the development of neural circuits. We show that exosome treatment increases proliferation in developing neural cultures and in vivo in dentate gyrus of P4 mouse brain. We compared the protein cargo and signaling bioactivity of exosomes released by hiPSC-derived neural cultures lacking MECP2, a model of the neurodevelopmental disorder Rett syndrome, with exosomes released by isogenic rescue control neural cultures. Quantitative proteomic analysis indicates that control exosomes contain multiple functional signaling networks known to be important for neuronal circuit development. Treating MECP2-knockdown human primary neural cultures with control exosomes rescues deficits in neuronal proliferation, differentiation, synaptogenesis, and synchronized firing, whereas exosomes from MECP2-deficient hiPSC neural cultures lack this capability. These data indicate that exosomes carry signaling information required to regulate neural circuit development

A Viral Immunoevasin Controls Innate Immunity by Targeting the Prototypical Natural Killer Cell Receptor Family

Natural killer (NK) cells play a key role in innate immunity by detecting alterations in self and non-self ligands via paired NK cell receptors (NKRs). Despite identification of numerous NKR-ligand interactions, physiological ligands for the prototypical NK1.1 orphan receptor remain elusive. Here, we identify a viral ligand for the inhibitory and activating NKRP1(NK1.1) receptors. This murine cytomegalovirus(MCMV)-encoded protein, m12, restrains NK cell effector function by directly engaging the inhibitory NKR-P1B receptor. However, m12 also interacts with the activating NKR-P1A/C receptors to counterbalance m12 decoy function. Structural analyses reveal that m12 sequesters a large NKR-P1 surface area via a ‘‘polar claw’’ mechanism. Polymorphisms in, and ablation of, the viral m12 protein and host NKR-P1B/C alleles impact NK cell responses in vivo. Thus, we identify the long-sought foreign ligand for this key immunoregulatory NKR family and reveal how it controls the evolutionary balance of immune recognition during host-pathogen interplay

Shielding behaviors and analysis of mechanical treatment of cements containing nanosized powders

In this study, we investigated linear attenuation coefficient (μ ), half value layer, tenth value layer at 243, 344, 866, 1088, 1112, 1528 keV. Mechanical properties of cements containing nanosized powders (nano-SiO₂, nano-Fe₂O₃, nano-Al₂O₃) are obtained. According to compressive strength results nano-SiO₂ added cementitious material gave the highest strength. Moreover, all the nanopowders added samples showed higher compressive strength with respect to reference sample. The experimental linear mass attenuation coefficients μ , half value layer, tenth value layer for cementitious material were compared with theoretical values obtained using XCOM. The experimental results were found to be in good agreement with the theoretical values

Mutation Spectrum of Fumarylacetoacetase Gene and Clinical Aspects of Tyrosinemia Type I Disease

Dursun, Ali/0000-0003-1104-9902; Ozgul, Riza Koksal/0000-0002-0283-635XWOS: 000294929800003PubMed: 23430822Tyrosinemia type I (OMIM 276700) is a rare, autosomal recessive disorder caused by a deficiency in the fumarylacetoacetate hydrolase (FAH) enzyme. This study examined the spectrum of FAH gene mutation in 32 patients with tyrosinemia type I. In addition, clinical and biochemical findings were evaluated to establish a genotype phenotype relationship in the patients. Mutation screening was performed using a 50K custom-designed resequencing microarray chip (TR_06_01r520489, Affymetrix) and sequencing analysis. Of the 12 different mutations found, 6 are categorized as novel. Three of the mutations-IVS6-1G>A, D233V, and IVS3-3C>G-are the most common in Turkish patients, comprising 25%, 17.1%, and 12.5% of mutant alleles, respectively. Clinical evaluations suggest that the spectrum of symptoms observed in the patients with very early and early disease were of the more nonspecific form, whereas the patients with late-presenting disease had more of the distinctive form over the course of the disease. This study adds support to the notion that the D233V mutation is specific to the Turkish population

Exosomes regulate neurogenesis and circuit assembly.

Exosomes are thought to be released by all cells in the body and to be involved in intercellular communication. We tested whether neural exosomes can regulate the development of neural circuits. We show that exosome treatment increases proliferation in developing neural cultures and in vivo in dentate gyrus of P4 mouse brain. We compared the protein cargo and signaling bioactivity of exosomes released by hiPSC-derived neural cultures lacking MECP2, a model of the neurodevelopmental disorder Rett syndrome, with exosomes released by isogenic rescue control neural cultures. Quantitative proteomic analysis indicates that control exosomes contain multiple functional signaling networks known to be important for neuronal circuit development. Treating MECP2-knockdown human primary neural cultures with control exosomes rescues deficits in neuronal proliferation, differentiation, synaptogenesis, and synchronized firing, whereas exosomes from MECP2-deficient hiPSC neural cultures lack this capability. These data indicate that exosomes carry signaling information required to regulate neural circuit development

Supplementary Material for: Interferon-Dependent Induction of Clr-b during Mouse Cytomegalovirus Infection Protects Bystander Cells from Natural Killer Cells via NKR-P1B-Mediated Inhibition

Natural killer (NK) cells are innate lymphocytes that aid in self-nonself discrimination by recognizing cells undergoing pathological alterations. The NKR-P1B inhibitory receptor recognizes Clr-b, a self-encoded marker of cell health downregulated during viral infection. Here, we show that Clr-b loss during mouse cytomegalovirus (MCMV) infection is predicated by a loss of Clr-b (<i>Clec2d</i>) promoter activity and nascent transcripts, driven in part by MCMV <i>ie3</i> (M122) activity. In contrast, uninfected bystander cells near MCMV-infected fibroblasts reciprocally upregulate Clr-b expression due to paracrine type-I interferon (IFN) signaling. Exposure of fibroblasts to type-I IFN augments <i>Clec2d</i> promoter activity and nascent Clr-b transcripts, dependent upon a cluster of IRF3/7/9 motifs located ∼200 bp upstream of the transcriptional start site. Cells deficient in type-I IFN signaling components revealed IRF9 and STAT1 as key transcription factors involved in Clr-b upregulation. In chromatin immunoprecipitation experiments, the <i>Clec2d</i> IRF cluster recruited STAT2 upon IFN-α exposure, confirming the involvement of ISGF3 (IRF9/STAT1/STAT2) in positively regulating the <i>Clec2d</i> promoter. These findings demonstrate that Clr-b is an IFN-stimulated gene on healthy bystander cells, in addition to a missing-self marker on MCMV-infected cells, and thereby enhances the dynamic range of innate self-nonself discrimination by NK cells

SARS-CoV-2 infects human brain organoids causing cell death and loss of synapses that can be rescued by treatment with Sofosbuvir.

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19), which was rapidly declared a pandemic by the World Health Organization (WHO). Early clinical symptomatology focused mainly on respiratory illnesses. However, a variety of neurological manifestations in both adults and newborns are now well-documented. To experimentally determine whether SARS-CoV-2 could replicate in and affect human brain cells, we infected iPSC-derived human brain organoids. Here, we show that SARS-CoV-2 can productively replicate and promote death of neural cells, including cortical neurons. This phenotype was accompanied by loss of excitatory synapses in neurons. Notably, we found that the U.S. Food and Drug Administration (FDA)-approved antiviral Sofosbuvir was able to inhibit SARS-CoV-2 replication and rescued these neuronal alterations in infected brain organoids. Given the urgent need for readily available antivirals, these results provide a cellular basis supporting repurposed antivirals as a strategic treatment to alleviate neurocytological defects that may underlie COVID-19- related neurological symptoms