Group A streptococcus induces CD1a-autoreactive T cells and promotes psoriatic inflammation

Group A Streptococcus (GAS) infection is associated with multiple clinical sequelae, including different subtypes of psoriasis. Such post-streptococcal disorders have been long known but are largely unexplained. CD1a is expressed at constitutively high levels by Langerhans cells and presents lipid antigens to T cells, but the potential relevance to GAS infection has not been studied. Here, we investigated whether GAS-responsive CD1a-restricted T cells contribute to the pathogenesis of psoriasis. Healthy individuals had high frequencies of circulating and cutaneous GAS-responsive CD4+ and CD8+ T cells with rapid effector functions, including the production of interleukin-22 (IL-22). Human skin and blood single-cell CITE-seq analyses of IL-22-producing T cells showed a type 17 signature with proliferative potential, whereas IFN-γ-producing T cells displayed cytotoxic T lymphocyte characteristics. Furthermore, individuals with psoriasis had significantly higher frequencies of circulating GAS-reactive T cells, enriched for markers of activation, cytolytic potential, and tissue association. In addition to responding to GAS, subsets of expanded GAS-reactive T cell clones/lines were found to be autoreactive, which included the recognition of the self-lipid antigen lysophosphatidylcholine. CD8+ T cell clones/lines produced cytolytic mediators and lysed infected CD1a-expressing cells. Furthermore, we established cutaneous models of GAS infection in a humanized CD1a transgenic mouse model and identified enhanced and prolonged local and systemic inflammation, with resolution through a psoriasis-like phenotype. Together, these findings link GAS infection to the CD1a pathway and show that GAS infection promotes the proliferation and activation of CD1a-autoreactive T cells, with relevance to post-streptococcal disease, including the pathogenesis and treatment of psoriasis

FMRP Interacts with C/D Box snoRNA in the Nucleus and Regulates Ribosomal RNA Methylation

Summary: FMRP is an RNA-binding protein that is known to localize in the cytoplasm and in the nucleus. Here, we have identified an interaction of FMRP with a specific set of C/D box snoRNAs in the nucleus. C/D box snoRNAs guide 2’O methylations of ribosomal RNA (rRNA) on defined sites, and this modification regulates rRNA folding and assembly of ribosomes. 2’O methylation of rRNA is partial on several sites in human embryonic stem cells, which results in ribosomes with differential methylation patterns. FMRP-snoRNA interaction affects rRNA methylation on several of these sites, and in the absence of FMRP, differential methylation pattern of rRNA is significantly altered. We found that FMRP recognizes ribosomes carrying specific methylation patterns on rRNA and the recognition of methylation pattern by FMRP may potentially determine the translation status of its target mRNAs. Thus, FMRP integrates its function in the nucleus and in the cytoplasm. : Molecular Interaction; Stem Cells Research; Omics Subject Areas: Molecular Interaction, Stem Cells Research, Omic

Developing Biliary Atresia-like Model by Treating Human Liver Organoids with Polyinosinic:Polycytidylic Acid (Poly (I:C))

Background: We explored the feasibility of creating BA-like organoids by treating human liver organoids with Polyinosinic:Polycytidylic acid (Poly I:C). Methods: Organoids were developed from the liver parenchyma collected during Kasai portoenterostomy (BA) and surgery for other liver disorders (non-BA). The non-BA organoids were co-cultured with poly I:C (40 µg/mL). The organoid morphology from both samples was compared on day 17. RNA-sequencing was performed to examine the transcriptomic differences. Results: Non-BA liver organoids developed into well-expanded spherical organoids with a single-cell layer of epithelial cells and a single vacuole inside. After poly I:C treatment, the majority of these organoids developed into an aberrant morphology with a high index of similarity to BA organoids which are multi-vacuoled and/or unexpanded. RNA-sequencing analysis revealed that 19 inflammatory genes were commonly expressed in both groups. Conditional cluster analysis revealed several genes (SOCS6, SOCS6.1, ARAF, CAMK2G, GNA1C, ITGA2, PRKACA, PTEN) that are involved in immune-mediated signaling pathway had a distinct pattern of expression in the poly I:C treated organoids. This resembled the expression pattern in BA organoids (p < 0.05). Conclusions: Poly I:C treated human liver organoids exhibit morphology and genetic signature highly compatible to organoids developed from BA liver samples. They are potential research materials to study immune-mediated inflammation in BA

Environmental Toxin Biliatresone-Induced Biliary Atresia-like Abnormal Cilia and Bile Duct Cell Development of Human Liver Organoids

Biliary atresia (BA) is a poorly understood and devastating obstructive bile duct disease of newborns. Biliatresone, a plant toxin, causes BA-like syndrome in some animals, but its relevance in humans is unknown. To validate the hypothesis that biliatresone exposure is a plausible BA disease mechanism in humans, we treated normal human liver organoids with biliatresone and addressed its adverse effects on organoid development, functions and cellular organization. The control organoids (without biliatresone) were well expanded and much bigger than biliatresone-treated organoids. Expression of the cholangiocyte marker CK19 was reduced, while the hepatocyte marker HFN4A was significantly elevated in biliatresone-treated organoids. ZO-1 (a tight junction marker) immunoreactivity was localized at the apical intercellular junctions in control organoids, while it was markedly reduced in biliatresone-treated organoids. Cytoskeleton F-actin was localized at the apical surface of the control organoids, but it was ectopically expressed at the apical and basal sides in biliatresone-treated organoids. Cholangiocytes of control organoids possess primary cilia and elicit cilia mechanosensory function. The number of ciliated cholangiocytes was reduced, and cilia mechanosensory function was hampered in biliatresone-treated organoids. In conclusion, biliatresone induces morphological and developmental changes in human liver organoids resembling those of our previously reported BA organoids, suggesting that environmental toxins could contribute to BA pathogenesis

Comparison of the Transcriptomes of Ginger (<i>Zingiber officinale</i> Rosc.) and Mango Ginger (<i>Curcuma amada</i> Roxb.) in Response to the Bacterial Wilt Infection

<div><p>Bacterial wilt in ginger (<i>Zingiber officinale</i> Rosc.) caused by <i>Ralstonia solanacearum</i> is one of the most important production constraints in tropical, sub-tropical and warm temperature regions of the world. Lack of resistant genotype adds constraints to the crop management. However, mango ginger (<i>Curcuma amada</i> Roxb.), which is resistant to <i>R. solanacearum</i>, is a potential donor, if the exact mechanism of resistance is understood. To identify genes involved in resistance to <i>R. solanacearum</i>, we have sequenced the transcriptome from wilt-sensitive ginger and wilt-resistant mango ginger using Illumina sequencing technology. A total of 26387032 and 22268804 paired-end reads were obtained after quality filtering for <i>C. amada</i> and <i>Z. officinale</i>, respectively. A total of 36359 and 32312 assembled transcript sequences were obtained from both the species. The functions of the unigenes cover a diverse set of molecular functions and biological processes, among which we identified a large number of genes associated with resistance to stresses and response to biotic stimuli. Large scale expression profiling showed that many of the disease resistance related genes were expressed more in <i>C. amada</i>. Comparative analysis also identified genes belonging to different pathways of plant defense against biotic stresses that are differentially expressed in either ginger or mango ginger. The identification of many defense related genes differentially expressed provides many insights to the resistance mechanism to <i>R. solanacearum</i> and for studying potential pathways involved in responses to pathogen. Also, several candidate genes that may underline the difference in resistance to <i>R. solanacearum</i> between ginger and mango ginger were identified. Finally, we have developed a web resource, ginger transcriptome database, which provides public access to the data. Our study is among the first to demonstrate the use of Illumina short read sequencing for <i>de novo</i> transcriptome assembly and comparison in non-model species of Zingiberaceae.</p></div

Box plot analysis of read mapping data after quantile normalization in <i>C. amada</i> and <i>Z. officinale</i> transcriptome.

<p>The transcript expression values (RPKM) overall distribution and variability of two cDNA libraries/samples were similar, indicating that they were comparable for identification of differentially expressed genes (DEGs) at the transcriptome level.</p

List of upregulated isoprene/terpene biosynthesis genes in <i>C. amada.</i>

<p>List of upregulated isoprene/terpene biosynthesis genes in <i>C. amada.</i></p

Summary of transcription factor unigenes of <i>C. amada</i> and <i>Z. officinale.</i>

<p>Summary of transcription factor unigenes of <i>C. amada</i> and <i>Z. officinale.</i></p

Divergence in the expression levels of transcription factors (TF) transcripts between C. amada and Z. officinale.

<p>Heat map and clustering analysis of the transcripts of genes encoding TFs are shown. Higher expression of TFs occurs in <i>C. amada</i>. The high expression levels are depicted in purple and low expression in red. Clustering and heat map was drawn with CLC Genomics Workbench based on an Euclidean distance matrix, after normalization of expression values.</p

Sequence length distribution of assembled contigs in the transcriptomes of C. amada and Z. officinale.

<p>Histogram presentation of sequence-length distribution for significant matches that was found. The x-axis indicates sequence sizes from 300 nt to >10001 nt. The y-axis indicates the number of contigs for every given size range.</p