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Little is known about chromosomal loopings involving proximal promoter and distal enhancer elements regulating GABAergic gene expression,including changes in schizophrenia and other psychiatric conditions linked to altered inhibition. Here,we map in human chromosome 2q31 the 3D configuration of 200 kb of linear sequence encompassing the GAD1 GABA synthesis enzyme gene locus,and we describe a loop formation involving the GAD1 transcription start site and intergenic noncoding DNA elements facilitating reporter gene expression. The GAD1-TSS(-50kbLoop) was enriched with nucleosomes epigenetically decorated with the transcriptional mark,histone H3 trimethylated at lysine 4,and was weak or absent in skin fibroblasts and pluripotent stem cells compared with neuronal cultures differentiated from them. In the prefrontal cortex of subjects with schizophrenia,GAD1-TSS(-50kbLoop) was decreased compared with controls,in conjunction with downregulated GAD1 expression. We generated transgenic mice expressing Gad2 promoter-driven green fluorescent protein-conjugated histone H2B and confirmed that Gad1-TSS(-55kbLoop),the murine homolog to GAD1-TSS(-50kbLoop),is a chromosomal conformation specific for GABAergic neurons. In primary neuronal culture,Gad1-TSS(-55kbLoop) and Gad1 expression became upregulated when neuronal activity was increased. We conclude that 3D genome architectures,including chromosomal loopings for promoter-enhancer interactions involved in the regulation of GABAergic gene expression,are conserved between the rodent and primate brain,and subject to developmental and activity-dependent regulation,and disordered in some cases with schizophrenia. More broadly,the findings presented here draw a connection between noncoding DNA,spatial genome architecture,and neuronal plasticity in development and disease. View Publication

Genome-wide association studies (GWASs) have reported many single nucleotide polymorphisms (SNPs) associated with psychiatric disorders,but knowledge is lacking regarding molecular mechanisms. Here we show that risk alleles spanning multiple genes across the 10q24.32 schizophrenia-related locus are associated in the human brain selectively with an increase in the expression of both BLOC-1 related complex subunit 7 (BORCS7) and a previously uncharacterized,human-specific arsenite methyltransferase (AS3MT) isoform (AS3MT(d2d3)),which lacks arsenite methyltransferase activity and is more abundant in individuals with schizophrenia than in controls. Conditional-expression analysis suggests that BORCS7 and AS3MT(d2d3) signals are largely independent. GWAS risk SNPs across this region are linked with a variable number tandem repeat (VNTR) polymorphism in the first exon of AS3MT that is associated with the expression of AS3MT(d2d3) in samples from both Caucasians and African Americans. The VNTR genotype predicts promoter activity in luciferase assays,as well as DNA methylation within the AS3MT gene. Both AS3MT(d2d3) and BORCS7 are expressed in adult human neurons and astrocytes,and they are upregulated during human stem cell differentiation toward neuronal fates. Our results provide a molecular explanation for the prominent 10q24.32 locus association,including a novel and evolutionarily recent protein that is involved in early brain development and confers risk for psychiatric illness. View Publication

Erasure of epigenetic memory is required to convert somatic cells towards pluripotency. Reactivation of the inactive X chromosome (Xi) has been used to model epigenetic reprogramming in mouse,but human studies are hampered by Xi epigenetic instability and difficulties in tracking partially reprogrammed iPSCs. Here we use cell fusion to examine the earliest events in the reprogramming-induced Xi reactivation of human female fibroblasts. We show that a rapid and widespread loss of Xi-associated H3K27me3 and XIST occurs in fused cells and precedes the bi-allelic expression of selected Xi-genes by many heterokaryons (30-50%). After cell division,RNA-FISH and RNA-seq analyses confirm that Xi reactivation remains partial and that induction of human pluripotency-specific XACT transcripts is rare (1%). These data effectively separate pre- and post-mitotic events in reprogramming-induced Xi reactivation and reveal a complex hierarchy of epigenetic changes that are required to reactivate the genes on the human Xi chromosome. View Publication

The blood disorder,β-thalassaemia,is considered an attractive target for gene correction. Site-specific triplex formation has been shown to induce DNA repair and thereby catalyse genome editing. Here we report that triplex-forming peptide nucleic acids (PNAs) substituted at the γ position plus stimulation of the stem cell factor (SCF)/c-Kit pathway yielded high levels of gene editing in haematopoietic stem cells (HSCs) in a mouse model of human β-thalassaemia. Injection of thalassemic mice with SCF plus nanoparticles containing γPNAs and donor DNAs ameliorated the disease phenotype,with sustained elevation of blood haemoglobin levels into the normal range,reduced reticulocytosis,reversal of splenomegaly and up to 7% β-globin gene correction in HSCs,with extremely low off-target effects. The combination of nanoparticle delivery,next generation γPNAs and SCF treatment may offer a minimally invasive treatment for genetic disorders of the blood that can be achieved safely and simply by intravenous administration. View Publication

Loeys-Dietz syndrome (LDS) is an autosomal-dominant connective tissue disorder,commonly caused by genetic mutation of transforming growth factor-beta receptor (TGFBR)-1 or TGFBR2. This study describes the generation of human induced pluripotent stem cells (hiPSCs) from peripheral blood mononuclear cells obtained from an LDS patient with TGFBR2 mutation (R193W). Analysis confirmed the cells had a normal karyotype,expressed typical pluripotency markers,had the ability to differentiate into all three germ layers in vivo,and retained the TGFBR2 mutation from the derived hiPSCs. This iPSC line represents a potentially useful tool for investigating LDS disease mechanisms. View Publication

After a single intravenous injection of suramin the rate of removal of the drug from the plasma into other tissue compartments of the rat is independent of initial concentration. The data can be fitted to the sum of two exponential functions,consistent with a two-compartment,open model system. Trypanosomes take up only small amounts of suramin in vivo and do not actively concentrate the drug within the cell. Uptake is apparently by a non-saturable process that decreases with time and is dependent on the amount of suramin already taken up. Once within the cell,suramin progressively inhibits respiration and glycolysis,such that,for a given exposure in vivo,inhibition of oxygen consumption is proportional to the total amount of suramin absorbed. It can be calculated that only a fraction (4--9%) of this total is required to inhibit respiration to the extent found in broken cell preparations. The combined inhibition of two key enzymes in glycolysis--the sn-glycerol-3-phosphate oxidase (EC unassigned) and the glycerol-3-phosphate dehydrogenase (NAD+) (sn-glycerol-3-phosphate: NAD+ 2-oxidoreductase,EC 1.1.1.8)--are sufficient to account for the differential inhibition of glucose and oxygen consumption and of pyruvate production,together with the small,but significant,production of glycerol. Even at the highest dose of suramin tolerated by the rat,trypanosomes continue to increase exponentially in the bloodstream for at least 6 h. The mean doubling time is increased from 4.6 h to a maximum of about 12.5 h in rats treated with doses of suramin in the range 25--150 mg/kg. In the light of these and other findings,it is concluded that part of the trypanocidal action of suramin results from the inhibition of ATP production by glycolysis. View Publication

Three series of analogs were regioselectively prepared from a protected forskolin precursor to afford 7-carbamoyl-7-desacetylforskolins (series 1),6-carbamoyl-7-desacetylforskolins (series 2),and 6-carbamoylforskolins (series 3). The analogs were pharmacologically evaluated for binding (IC50) to and activation (EC50) of type I adenylyl cyclase in membranes from stably transfected Sf9 cell lines expressing a single adenylate cyclase subtype. The following ranges were determined for the IC50's and EC50's of each individual series: series 1,IC50 = 43-1600 nM,EC50 = 0.5-9.6 microM; series 2,IC50 = 65-680 nM,EC50 = 0.63-6.5 microM; series 3,IC50 = 21-271 nM,EC50 = 0.5-8.1 microM (forskolin IC50 = 41 nM and EC50 = 0.5 microM). Activation paralleled binding; however,some analogs exhibited poor binding and good activation whereas others demonstrated good binding but poor activation. Steric bulk tended to diminish binding and activation when at the 6- or 7-position,although bulk was accommodated at the 6-position if the 7-site was reacetylated. Acylation of the 7-position by the carbamoyl linker or acetyl was important for obtaining good binding and activation; however,the effect was more pronounced with binding. For both binding and activation,small,linear,lipophilic substituents (propyl,allyl,isopropyl) are well tolerated at the 7-position but less so in the 6-position,even when the 7-site is reacetylated. Planar aromatic moieties (phenyl and 2-pyridinyl) demonstrated moderate to good potency for binding and activation when located at either the 6- or 7-positions. There is an overall trend toward increasing potency for both binding and activation with polar substituents. View Publication

We have identified three non-cross-reacting anti-human CD44 monoclonal antibodies that have significant positive or negative (or no) effects on normal human haemopoiesis in the long-term culture (LTC) system. These effects manifested as increases or decreases in the number of LTC-initiating cells (LTC-IC),and the number of colony-forming cells (CFC) recovered from cultures in which either unseparated or highly purified CD34+ CD38- normal marrow cells were placed on pre-established normal marrow feeder layers in the presence or absence of each antibody. The effects seen were rapid and sustained,and dependent on the presence of a preformed feeder layer. Interestingly,the same anti-CD44 antibodies had no effect on the maintenance of leukaemic (Ph+) progenitors (from patients with chronic myeloid leukaemia) when these cells were cultured on preformed feeder layers established from normal marrow. CD44 appears to be part of a mechanism by which stromal elements can regulate primitive normal haemopoietic cells but not their leukaemic (Ph+) counterparts. View Publication

The prototype of a new class of antiproliferative phospholipid analogs,hexadecylphosphocholine (HePC),has been shown to inhibit tumor growth and is currently used for the treatment of cutaneous metastases of mammary carcinomas. Although several cellular targets of HePC,e.g. protein kinase C and CTP:phosphocholine cytidylyltransferase,have been proposed,the mechanisms of HePC-induced anticancer activity are still unclear. Considering that the antiproliferative effect of HePC correlates with inhibition of phosphatidylcholine biosynthesis,which is tightly coupled to sphingomyelin biosynthesis,we tested the hypothesis that treatment of cells with the anticancer drug leads to increased cellular ceramide and subsequently to apoptotic cell death. In the present study,we showed that 25 micromol/liter HePC induced apoptosis. In further experiments,we demonstrated that HePC inhibited the incorporation of radiolabeled choline into phosphatidylcholine and at a later time point into sphingomyelin. This was confirmed by metabolic labeling of the lipid backbone using radiolabeled serine,and it was shown that HePC decreased the incorporation of serine into sphingomyelin by 35% and simultaneously increased the incorporation of serine into ceramide by 70%. Determination of the amount of ceramide revealed an increase of 53% in HePC-treated cells compared with controls. In accordance with the hypothesis that elevated ceramide levels may be the missing link between the metabolic effects of HePC and its proapoptotic properties,HePC-induced apoptosis was blocked by fumonisin B1,an inhibitor of ceramide synthesis. Furthermore,we found that membrane-permeable ceramides additively increased the apoptotic effect of HePC. View Publication

Microtubule-associated protein (MAP) 2 has been perceived as a static cytoskeletal protein enriched in neuronal dendritic shafts. Emerging evidence indicates dynamic functions for various MAPs in activity-dependent synaptic plasticity. However,it is unclear how MAP2 is associated with synaptic plasticity mechanisms. Here,we demonstrate that specific silencing of high-molecular-weight MAP2 in vivo abolished induction of long-term potentiation (LTP) in the Schaffer collateral pathway of CA1 pyramidal neurons and in vitro blocked LTP-induced surface delivery of AMPA receptors and spine enlargement. In mature hippocampal neurons,we observed rapid translocation of a subpopulation of MAP2,present in dendritic shafts,to spines following LTP stimulation. Time-lapse confocal imaging showed that spine translocation of MAP2 was coupled with LTP-induced spine enlargement. Consistently,immunogold electron microscopy revealed that LTP stimulation of the Schaffer collateral pathway promoted MAP2 labeling in spine heads of CA1 neurons. This translocation depended on NMDA receptor activation and Ras-MAPK signaling. Furthermore,LTP stimulation led to an increase in surface-expressed AMPA receptors specifically in the neurons with MAP2 spine translocation. Altogether,this study indicates a novel role for MAP2 in LTP mechanisms and suggests that MAP2 participates in activity-dependent synaptic plasticity in mature hippocampal networks. View Publication

PURPOSE Three observations drove this study. First,2'-5'-oligoadenylate synthetase-like protein (OASL) is a negative regulator of type I interferon (IFN). Second,type I IFN plays a central role during virus infections and the pathogenesis of various diseases,including asthma. Third,influenza A virus (IAV) causes non-eosinophilic asthma. To evaluate the potential relationships between OASL,type I IFN,and pulmonary innate immune cells in IAV-induced acute airway inflammation by using Oasl1-/- mice. METHODS Asthma was induced in wild-type (WT) and Oasl1-/- mice with IAV or ovalbumin (OVA). Airway hyperreactivity (AHR) and immune cell infiltration in the bronchoalveolar lavage (BAL) fluids were measured. The immune cells in the lungs were analyzed by flow cytometry. To investigate the ability of type I IFN to shape the response of lung type 2 innate lymphoid cells (ILC2s),IFN-$\alpha$ was treated intratracheally. Plasmacytoid dendritic cells (pDCs) sorted from bone marrow and ILC2s sorted from lungs of naive mice were co-cultured with/without interferon-alpha receptor subunit 1 (IFNAR-1)-blocking antibodies. RESULTS In the IAV-induced asthma model,Oasl1-/- mice developed greater AHR and immune cell infiltration in the BAL fluids than WT mice. This was not observed in OVA-induced asthma,a standard model of allergen-induced asthma. The lungs of infected Oasl1-/- mice also had elevated DC numbers and Ifna expression and depressed IAV-induced ILC2 responses,namely,proliferation and type 2 cytokine and amphiregulin production. Intratracheal administration of type I IFN in na{\{i}}ve mice suppressed lung ILC2 production of type 2 cytokines and amphiregulin. Co-culture of ILC2s with pDCs showed that pDCs inhibit the function of ILC2s by secreting type I IFN. CONCLUSIONS OASL1 may impede the IAV-induced acute airway inflammation that drives AHR by inhibiting IAV-induced type I IFN production from lung DCs thereby preserving the functions of lung ILC2s including their amphiregulin production." View Publication