A Convenient Model of Severe, High Incidence Autoimmune Gastritis Caused by Polyclonal Effector T Cells and without Perturbation of Regulatory T Cells

Autoimmune gastritis results from the breakdown of T cell tolerance to the gastric H+/K+ ATPase. The gastric H+/K+ ATPase is responsible for the acidification of gastric juice and consists of an α subunit (H/Kα) and a β subunit (H/Kβ). Here we show that CD4+ T cells from H/Kα-deficient mice (H/Kα−/−) are highly pathogenic and autoimmune gastritis can be induced in sublethally irradiated wildtype mice by adoptive transfer of unfractionated CD4+ T cells from H/Kα−/− mice. All recipient mice consistently developed the most severe form of autoimmune gastritis 8 weeks after the transfer, featuring hypertrophy of the gastric mucosa, complete depletion of the parietal and zymogenic cells, and presence of autoantibodies to H+/K+ ATPase in the serum. Furthermore, we demonstrated that the disease significantly affected stomach weight and stomach pH of recipient mice. Depletion of parietal cells in this disease model required the presence of both H/Kα and H/Kβ since transfer of H/Kα−/− CD4+ T cells did not result in depletion of parietal cells in H/Kα−/− or H/Kβ−/− recipient mice. The consistency of disease severity, the use of polyclonal T cells and a specific T cell response to the gastric autoantigen make this an ideal disease model for the study of many aspects of organ-specific autoimmunity including prevention and treatment of the disease

Mapping genomic loci implicates genes and synaptic biology in schizophrenia

Schizophrenia has a heritability of 60-80%1, much of which is attributable to common risk alleles. Here, in a two-stage genome-wide association study of up to 76,755 individuals with schizophrenia and 243,649 control individuals, we report common variant associations at 287 distinct genomic loci. Associations were concentrated in genes that are expressed in excitatory and inhibitory neurons of the central nervous system, but not in other tissues or cell types. Using fine-mapping and functional genomic data, we identify 120 genes (106 protein-coding) that are likely to underpin associations at some of these loci, including 16 genes with credible causal non-synonymous or untranslated region variation. We also implicate fundamental processes related to neuronal function, including synaptic organization, differentiation and transmission. Fine-mapped candidates were enriched for genes associated with rare disruptive coding variants in people with schizophrenia, including the glutamate receptor subunit GRIN2A and transcription factor SP4, and were also enriched for genes implicated by such variants in neurodevelopmental disorders. We identify biological processes relevant to schizophrenia pathophysiology; show convergence of common and rare variant associations in schizophrenia and neurodevelopmental disorders; and provide a resource of prioritized genes and variants to advance mechanistic studies

Mapping genomic loci prioritises genes and implicates synaptic biology in schizophrenia

Schizophrenia has a heritability of 60–80%1, much of which is attributable to common risk alleles. Here, in a two-stage genome-wide association study of up to 76,755 individuals with schizophrenia and 243,649 control individuals, we report common variant associations at 287 distinct genomic loci. Associations were concentrated in genes that are expressed in excitatory and inhibitory neurons of the central nervous system, but not in other tissues or cell types. Using fine-mapping and functional genomic data, we identify 120 genes (106 protein-coding) that are likely to underpin associations at some of these loci, including 16 genes with credible causal non-synonymous or untranslated region variation. We also implicate fundamental processes related to neuronal function, including synaptic organization, differentiation and transmission. Fine-mapped candidates were enriched for genes associated with rare disruptive coding variants in people with schizophrenia, including the glutamate receptor subunit GRIN2A and transcription factor SP4, and were also enriched for genes implicated by such variants in neurodevelopmental disorders. We identify biological processes relevant to schizophrenia pathophysiology; show convergence of common and rare variant associations in schizophrenia and neurodevelopmental disorders; and provide a resource of prioritized genes and variants to advance mechanistic studies

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Tracking protein aggregation and mislocalization in cells with flow cytometry

We applied pulse-shape analysis (PulSA) to monitor protein localization changes in mammalian cells by flow cytometry. PulSA enabled high-throughput tracking of protein aggregation, translocation from the cytoplasm to the nucleus and trafficking from the plasma membrane to the Golgi as well as stress-granule formation. Combining PulSA with tetracysteine-based oligomer sensors in a cell model of Huntington's disease enabled further separation of cells enriched with monomers, oligomers and inclusion bodies

Autoimmune gastritis does not develop in the absence of gastric H/Kα or H/Kβ.

<p>Gastric pathology in (A) H/Kα^−/− mice received either H/Kα^−/− CD4⁺ T cells or no inoculum (−) (B) H/Kβ^−/− mice received either H/Kα^−/− CD4⁺ T cells or no inoculum (−) (C) WT mice received H/Kα^−/− CD4⁺ T cells. Images representative of results of at least 9 mice in each group are shown. (D) Serum samples were collected from H/Kα^−/−, H/Kβ^−/− or WT mice that received CD4⁺ T cells from H/Kα^−/− mice. H⁺/K⁺ ATPase-specific autoantibodies in serum were detected by ELISA using serial 2-fold dilutions of mouse sera, with a starting dilution factor of 50. Data pooled from four independent experiments. Error bars, standard error.</p

Cellularity of stomach-draining and non-draining lymph nodes.

<p>(A) The number of cells in the paragastric and inguinal lymph nodes from recipient mice 8 weeks after transfer of either wildtype or H/Kα^−/− CD4⁺ T cells. (B) The percentage of effector/memory T cells in the donor population with the phenotype CD44^hiCD62L^lo in CD90.2⁺ CD4⁺ T cells. Data pooled from four independent experiments. Each circle represents the data from one mouse. Mann-Whitney <i>U</i> test was used; bars, mean, **, P<0.01 and ***, P<0.001.</p

Elevated immune response to immunisation with H⁺/K⁺ ATPase in H/Kα^−/− mice.

<p>WT and H/Kα^−/− mice were immunised with H⁺/K⁺ ATPase as described in “<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0027153#s4" target="_blank">Materials and Methods</a>”. (A) H⁺/K⁺ ATPase-specific autoantibodies in serum were detected by ELISA using serial 2-fold dilutions of mouse sera, with a starting dilution factor of 5. Data is representative of three independent experiments. Error bars, standard error. (B) Cells from inguinal lymph nodes were cultured for 72 hrs with splenic DC, and T cell proliferation was assessed by incorporation of ³H-thymidine. For each mouse, T cells were cultured in triplicate with either DC with gastric membrane or with DC alone. The mean cpm of T cells cultured with DC with antigen was divided by the mean cpm of the same T cells cultured with DC alone to calculate the stimulation index. Data pooled from four independent experiments. In (B), each circle represents the data from one mouse. Mann-Whitney <i>U</i> test was used; bars, mean and ***, P<0.001.</p

Mice with autoimmune gastritis have an increased level of Foxp3⁺ Treg cells in the stomach.

<p>Cells were harvested from (A, B) paragastric lymph node, inguinal lymph node and (A, C) stomach tissue for intracellular staining of Foxp3. The numbers indicate the percentages of Foxp3⁺ Treg cells in donor CD90.2⁺CD4⁺ T cells in paragastric and inguinal lymph nodes and Foxp3⁺ Treg cells in total CD4⁺ T cells in stomach tissue. Data pooled from three independent experiments. In (B) and (C), each circle represents the data from one mouse. Mann-Whitney <i>U</i> test was used; bars, mean, and **, P<0.01.</p

Severity of autoimmune gastritis correlates to stomach weight.

<p>Mice were killed at indicated time points after transfer of CD4⁺ T cells from H/Kα^−/− mice and the severity of autoimmune gastritis was determined. Data were pooled from six independent experiments. Each circle represents the data from one mouse. Bars, mean.</p