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1.
Cell ; 182(3): 542-544, 2020 08 06.
Article in English | MEDLINE | ID: mdl-32763186

ABSTRACT

Serotonin production by enterochromaffin cells (ECs) is microbiota-dependent, but the mechanism of this is unknown. In this issue of Cell, Sugisawa et al. demonstrate that Piezo1 in ECs senses single-strand RNA (ssRNA) from intestinal microbiota to promote serotonin production. Deletion of Piezo1 in intestinal epithelium promotes bone formation, decreases peristalsis, and protects from colitis because of decreased serotonin.


Subject(s)
Gastrointestinal Microbiome , Serotonin , Enterochromaffin Cells , Ion Channels/genetics , RNA
2.
Immunity ; 56(5): 1115-1131.e9, 2023 05 09.
Article in English | MEDLINE | ID: mdl-36917985

ABSTRACT

Intestinal IL-17-producing T helper (Th17) cells are dependent on adherent microbes in the gut for their development. However, how microbial adherence to intestinal epithelial cells (IECs) promotes Th17 cell differentiation remains enigmatic. Here, we found that Th17 cell-inducing gut bacteria generated an unfolded protein response (UPR) in IECs. Furthermore, subtilase cytotoxin expression or genetic removal of X-box binding protein 1 (Xbp1) in IECs caused a UPR and increased Th17 cells, even in antibiotic-treated or germ-free conditions. Mechanistically, UPR activation in IECs enhanced their production of both reactive oxygen species (ROS) and purine metabolites. Treating mice with N-acetyl-cysteine or allopurinol to reduce ROS production and xanthine, respectively, decreased Th17 cells that were associated with an elevated UPR. Th17-related genes also correlated with ER stress and the UPR in humans with inflammatory bowel disease. Overall, we identify a mechanism of intestinal Th17 cell differentiation that emerges from an IEC-associated UPR.


Subject(s)
Endoplasmic Reticulum Stress , Intestinal Mucosa , Th17 Cells , Endoplasmic Reticulum Stress/drug effects , Intestinal Mucosa/drug effects , Intestinal Mucosa/metabolism , Th17 Cells/cytology , Th17 Cells/metabolism , Cell Differentiation , Humans , Animals , Mice , Mice, Transgenic , Anti-Bacterial Agents/pharmacology
3.
Mol Cell ; 81(11): 2317-2331.e6, 2021 06 03.
Article in English | MEDLINE | ID: mdl-33909988

ABSTRACT

Aberrant energy status contributes to multiple metabolic diseases, including obesity, diabetes, and cancer, but the underlying mechanism remains elusive. Here, we report that ketogenic-diet-induced changes in energy status enhance the efficacy of anti-CTLA-4 immunotherapy by decreasing PD-L1 protein levels and increasing expression of type-I interferon (IFN) and antigen presentation genes. Mechanistically, energy deprivation activates AMP-activated protein kinase (AMPK), which in turn, phosphorylates PD-L1 on Ser283, thereby disrupting its interaction with CMTM4 and subsequently triggering PD-L1 degradation. In addition, AMPK phosphorylates EZH2, which disrupts PRC2 function, leading to enhanced IFNs and antigen presentation gene expression. Through these mechanisms, AMPK agonists or ketogenic diets enhance the efficacy of anti-CTLA-4 immunotherapy and improve the overall survival rate in syngeneic mouse tumor models. Our findings reveal a pivotal role for AMPK in regulating the immune response to immune-checkpoint blockade and advocate for combining ketogenic diets or AMPK agonists with anti-CTLA4 immunotherapy to combat cancer.


Subject(s)
AMP-Activated Protein Kinases/genetics , B7-H1 Antigen/genetics , Breast Neoplasms/genetics , CTLA-4 Antigen/genetics , Colorectal Neoplasms/genetics , Immune Checkpoint Inhibitors , AMP-Activated Protein Kinases/immunology , Allografts , Animals , Antibodies, Neutralizing/pharmacology , Antineoplastic Agents/pharmacology , B7-H1 Antigen/immunology , Biphenyl Compounds/pharmacology , Breast Neoplasms/immunology , Breast Neoplasms/mortality , Breast Neoplasms/therapy , CTLA-4 Antigen/antagonists & inhibitors , CTLA-4 Antigen/immunology , Cell Line, Tumor , Colorectal Neoplasms/immunology , Colorectal Neoplasms/mortality , Colorectal Neoplasms/therapy , Diet, Ketogenic/methods , Energy Metabolism/drug effects , Energy Metabolism/genetics , Enhancer of Zeste Homolog 2 Protein/genetics , Enhancer of Zeste Homolog 2 Protein/immunology , Female , Gene Expression Regulation, Neoplastic , Humans , Immunotherapy/methods , MARVEL Domain-Containing Proteins/genetics , MARVEL Domain-Containing Proteins/immunology , Mice , Mice, Inbred C57BL , Mice, Nude , Pyrones/pharmacology , Signal Transduction , Survival Analysis , Thiophenes/pharmacology
4.
PLoS Biol ; 18(7): e3000747, 2020 07.
Article in English | MEDLINE | ID: mdl-32644995

ABSTRACT

CRISPR-Staphylococcus aureus Cas9 (CRISPR-SaCas9) has been harnessed as an effective in vivo genome-editing tool to manipulate genomes. However, off-target effects remain a major bottleneck that precludes safe and reliable applications in genome editing. Here, we characterize the off-target effects of wild-type (WT) SaCas9 at single-nucleotide (single-nt) resolution and describe a directional screening system to identify novel SaCas9 variants with desired properties in human cells. Using this system, we identified enhanced-fidelity SaCas9 (efSaCas9) (variant Mut268 harboring the single mutation of N260D), which could effectively distinguish and reject single base-pair mismatches. We demonstrate dramatically reduced off-target effects (approximately 2- to 93-fold improvements) of Mut268 compared to WT using targeted deep-sequencing analyses. To understand the structural origin of the fidelity enhancement, we find that N260, located in the REC3 domain, orchestrates an extensive network of contacts between REC3 and the guide RNA-DNA heteroduplex. efSaCas9 can be broadly used in genome-editing applications that require high fidelity. Furthermore, this study provides a general strategy to rapidly evolve other desired CRISPR-Cas9 traits besides enhanced fidelity, to expand the utility of the CRISPR toolkit.


Subject(s)
Bacterial Proteins/metabolism , CRISPR-Associated Protein 9/metabolism , Staphylococcus aureus/metabolism , Gene Library , Genetic Engineering , Genetic Loci , Genome, Human , HEK293 Cells , Humans , Nucleotides/genetics , Phenotype , Reproducibility of Results , Transcriptional Activation/genetics
5.
Proc Natl Acad Sci U S A ; 114(7): 1660-1665, 2017 02 14.
Article in English | MEDLINE | ID: mdl-28137859

ABSTRACT

The prokaryotic CRISPR/Cas9 system has recently emerged as a powerful tool for genome editing in mammalian cells with the potential to bring curative therapies to patients with genetic diseases. However, efficient in vivo delivery of this genome editing machinery and indeed the very feasibility of using these techniques in vivo remain challenging for most tissue types. Here, we show that nonreplicable Cas9/sgRNA ribonucleoproteins can be used to correct genetic defects in skin stem cells of postnatal recessive dystrophic epidermolysis bullosa (RDEB) mice. We developed a method to locally deliver Cas9/sgRNA ribonucleoproteins into the skin of postnatal mice. This method results in rapid gene editing in epidermal stem cells. Using this method, we show that Cas9/sgRNA ribonucleoproteins efficiently excise exon80, which covers the point mutation in our RDEB mouse model, and thus restores the correct localization of the collagen VII protein in vivo. The skin blistering phenotype is also significantly ameliorated after treatment. This study provides an in vivo gene correction strategy using ribonucleoproteins as curative treatment for genetic diseases in skin and potentially in other somatic tissues.


Subject(s)
Epidermolysis Bullosa Dystrophica/therapy , Gene Editing/methods , Ribonucleoproteins/genetics , Stem Cells/metabolism , Animals , CRISPR-Cas Systems/genetics , Collagen Type VII/genetics , Collagen Type VII/metabolism , Disease Models, Animal , Epidermolysis Bullosa Dystrophica/genetics , Genes, Recessive , Genetic Therapy/methods , Humans , Mice, Knockout , Mice, Transgenic , Mutation , Reproducibility of Results , Ribonucleoproteins/metabolism , Skin/metabolism , Skin/pathology
6.
Proc Natl Acad Sci U S A ; 113(5): 1256-60, 2016 Feb 02.
Article in English | MEDLINE | ID: mdl-26787905

ABSTRACT

In eukaryotes, DNA double-strand breaks (DSBs), one of the most harmful types of DNA damage, are repaired by homologous repair (HR) and nonhomologous end-joining (NHEJ). Surprisingly, in cells deficient for core classic NHEJ factors such as DNA ligase IV (Lig4), substantial end-joining activities have been observed in various situations, suggesting the existence of alternative end-joining (A-EJ) activities. Several putative A-EJ factors have been proposed, although results are mostly controversial. By using a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system, we generated mouse CH12F3 cell lines in which, in addition to Lig4, either Lig1 or nuclear Lig3, representing the cells containing a single DNA ligase (Lig3 or Lig1, respectively) in their nucleus, was completely ablated. Surprisingly, we found that both Lig1- and Lig3-containing complexes could efficiently catalyze A-EJ for class switching recombination (CSR) in the IgH locus and chromosomal deletions between DSBs generated by CRISPR/Cas9 in cis-chromosomes. However, only deletion of nuclear Lig3, but not Lig1, could significantly reduce the interchromosomal translocations in Lig4(-/-) cells, suggesting the unique role of Lig3 in catalyzing chromosome translocation. Additional sequence analysis of chromosome translocation junction microhomology revealed the specificity of different ligase-containing complexes. The data suggested the existence of multiple DNA ligase-containing complexes in A-EJ.


Subject(s)
DNA Damage , DNA End-Joining Repair , DNA Ligases/metabolism , Isoenzymes/metabolism , Animals , Cell Line , Cell Nucleus/enzymology , DNA Ligase ATP , Mice , Translocation, Genetic
7.
J Exp Med ; 220(11)2023 11 06.
Article in English | MEDLINE | ID: mdl-37695524

ABSTRACT

Epithelial cells play a crucial role in barrier defense. Here, Moniruzzaman et al. (2023. J. Exp. Med.https://doi.org/10.1084/jem.20230106) discovered that interleukin-22 (IL-22) represses MHC class II expression by epithelial cells with an opposite impact on chronic inflammatory disease and viral infection.


Subject(s)
Epithelial Cells , Interleukins , Genes, MHC Class II , Interleukin-22
8.
STAR Protoc ; 4(3): 102485, 2023 Sep 15.
Article in English | MEDLINE | ID: mdl-37566548

ABSTRACT

Studying gene function in T cells is crucial for understanding physiology and disease pathogenesis. Here, we provide a protocol to examine the role of specific genes in CD4+ T cell differentiation in the intestine. We describe steps for isolating naïve CD4+ T cells from mouse spleens and transferring them to recipient mice. We detail procedures to isolate lamina propria cells and analyze CD4+ T subsets using flow cytometry. This protocol is useful in the study of mucosal immune functions. For complete details on the use and execution of this protocol, please refer to Duan et al.1.


Subject(s)
CD4-Positive T-Lymphocytes , Mucous Membrane , Animals , Mice , Flow Cytometry , Cell Differentiation , Intestine, Small
9.
J Exp Med ; 220(1)2023 01 02.
Article in English | MEDLINE | ID: mdl-36413219

ABSTRACT

Intelectin-1 (ITLN1) is a lectin secreted by intestinal epithelial cells (IECs) and upregulated in human ulcerative colitis (UC). We investigated how ITLN1 production is regulated in IECs and the biological effects of ITLN1 at the host-microbiota interface using mouse models. Our data show that ITLN1 upregulation in IECs from UC patients is a consequence of activating the unfolded protein response. Analysis of microbes coated by ITLN1 in vivo revealed a restricted subset of microorganisms, including the mucolytic bacterium Akkermansia muciniphila. Mice overexpressing intestinal ITLN1 exhibited decreased inner colonic mucus layer thickness and closer apposition of A. muciniphila to the epithelial cell surface, similar to alterations reported in UC. The changes in the inner mucus layer were microbiota and A. muciniphila dependent and associated with enhanced sensitivity to chemically induced and T cell-mediated colitis. We conclude that by determining the localization of a select group of bacteria to the mucus layer, ITLN1 modifies this critical barrier. Together, these findings may explain the impact of ITLN1 dysregulation on UC pathogenesis.


Subject(s)
Colitis, Ulcerative , Verrucomicrobia , Humans , Mice , Animals , Verrucomicrobia/metabolism , Mucus/metabolism , Lectins , Colitis, Ulcerative/metabolism , Colitis, Ulcerative/microbiology , Colitis, Ulcerative/pathology
10.
Nat Biomed Eng ; 6(4): 476-494, 2022 04.
Article in English | MEDLINE | ID: mdl-35314801

ABSTRACT

The cellular composition of barrier epithelia is essential to organismal homoeostasis. In particular, within the small intestine, adult stem cells establish tissue cellularity, and may provide a means to control the abundance and quality of specialized epithelial cells. Yet, methods for the identification of biological targets regulating epithelial composition and function, and of small molecules modulating them, are lacking. Here we show that druggable biological targets and small-molecule regulators of intestinal stem cell differentiation can be identified via multiplexed phenotypic screening using thousands of miniaturized organoid models of intestinal stem cell differentiation into Paneth cells, and validated via longitudinal single-cell RNA-sequencing. We found that inhibitors of the nuclear exporter Exportin 1 modulate the fate of intestinal stem cells, independently of known differentiation cues, significantly increasing the abundance of Paneth cells in the organoids and in wild-type mice. Physiological organoid models of the differentiation of intestinal stem cells could find broader utility for the screening of biological targets and small molecules that can modulate the composition and function of other barrier epithelia.


Subject(s)
Organoids , Paneth Cells , Animals , Cell Differentiation , Intestines , Mice , Paneth Cells/physiology , Stem Cells
11.
Cell Rep ; 35(13): 109288, 2021 06 29.
Article in English | MEDLINE | ID: mdl-34192543

ABSTRACT

The hepatitis B virus (HBV) infects 257 million people worldwide. HBV infection requires establishment and persistence of covalently closed circular (ccc) DNA, a viral episome, in nucleus. Here, we study cccDNA spatial localization in the 3D host genome by using chromosome conformation capture-based sequencing analysis and fluorescence in situ hybridization (FISH). We show that transcriptionally inactive cccDNA is not randomly distributed in host nucleus. Rather, it is preferentially accumulated at specialized areas, including regions close to chromosome 19 (chr.19). Activation of the cccDNA is apparently associated with its re-localization, from a pre-established heterochromatin hub formed by 5 regions of chr.19 to transcriptionally active regions formed by chr.19 and nearby chromosomes including chr.16, 17, 20, and 22. This active versus inactive positioning at discrete regions of the host genome is primarily controlled by the viral HBx protein and by host factors including the structural maintenance of chromosomes protein 5/6 (SMC5/6) complex.


Subject(s)
Chromosomes, Human, Pair 19/genetics , Genome, Human , Hepatitis B virus/genetics , Hepatitis B/genetics , Hepatitis B/virology , Plasmids/genetics , Transcription, Genetic , Base Sequence , Cells, Cultured , DNA, Viral/genetics , Genome, Viral , Hep G2 Cells , Hepatocytes/pathology , Hepatocytes/virology , Heterochromatin/metabolism , Humans
12.
Nat Commun ; 10(1): 2756, 2019 06 21.
Article in English | MEDLINE | ID: mdl-31227702

ABSTRACT

Flight loss in birds is as characteristic of the class Aves as flight itself. Although morphological and physiological differences are recognized in flight-degenerate bird species, their contributions to recurrent flight degeneration events across modern birds and underlying genetic mechanisms remain unclear. Here, in an analysis of 295 million nucleotides from 48 bird genomes, we identify two convergent sites causing amino acid changes in ATGLSer321Gly and ACOT7Ala197Val in flight-degenerate birds, which to our knowledge have not previously been implicated in loss of flight. Functional assays suggest that Ser321Gly reduces lipid hydrolytic ability of ATGL, and Ala197Val enhances acyl-CoA hydrolytic activity of ACOT7. Modeling simulations suggest a switch of main energy sources from lipids to carbohydrates in flight-degenerate birds. Our results thus suggest that physiological convergence plays an important role in flight degeneration, and anatomical convergence often invoked may not.


Subject(s)
Biological Evolution , Birds/physiology , Energy Metabolism/genetics , Flight, Animal/physiology , Genome/genetics , Animals , Carbohydrate Metabolism/physiology , Genomics/methods , Lipase/genetics , Lipase/metabolism , Lipolysis/physiology , Palmitoyl-CoA Hydrolase/genetics , Palmitoyl-CoA Hydrolase/metabolism , Phylogeny
13.
Science ; 363(6430): 993-998, 2019 03 01.
Article in English | MEDLINE | ID: mdl-30819965

ABSTRACT

Immunoglobulin A (IgA) is the major secretory immunoglobulin isotype found at mucosal surfaces, where it regulates microbial commensalism and excludes luminal factors from contacting intestinal epithelial cells (IECs). IgA is induced by both T cell-dependent and -independent (TI) pathways. However, little is known about TI regulation. We report that IEC endoplasmic reticulum (ER) stress induces a polyreactive IgA response, which is protective against enteric inflammation. IEC ER stress causes TI and microbiota-independent expansion and activation of peritoneal B1b cells, which culminates in increased lamina propria and luminal IgA. Increased numbers of IgA-producing plasma cells were observed in healthy humans with defective autophagy, who are known to exhibit IEC ER stress. Upon ER stress, IECs communicate signals to the peritoneum that induce a barrier-protective TI IgA response.


Subject(s)
Endoplasmic Reticulum Stress , Epithelial Cells/immunology , Immunity, Mucosal , Immunoglobulin A/immunology , Intestinal Mucosa/immunology , Animals , Autophagy , Autophagy-Related Proteins/genetics , Humans , Inflammation , Mice , Mice, Inbred C57BL , Mice, Knockout , Plasma Cells/immunology , Tissue Culture Techniques , X-Box Binding Protein 1/genetics
14.
Genome Biol ; 19(1): 39, 2018 03 22.
Article in English | MEDLINE | ID: mdl-29566733

ABSTRACT

CRISPR/dCas9 binds precisely to defined genomic sequences through targeting of guide RNA (gRNA) sequences. In vivo imaging of genomic loci can be achieved by recruiting fluorescent proteins using either dCas9 or gRNA. We thoroughly validate and compare the effectiveness and specificity of several dCas9/gRNA genome labeling systems. Surprisingly, we discover that in the gRNA-labeling strategies, accumulation of tagged gRNA transcripts leads to non-specific labeling foci. Furthermore, we develop novel bimolecular fluorescence complementation (BIFC) methods that combine the advantages of both dCas9-labeling and gRNA-labeling strategies. The BIFC-dCas9/gRNA methods demonstrate high signal-to-noise ratios and have no non-specific foci.


Subject(s)
CRISPR-Cas Systems , Chromosomes, Human , Endodeoxyribonucleases , Microscopy, Fluorescence , Genome , HEK293 Cells , Humans , Optical Imaging , RNA/metabolism
15.
Genome Biol ; 19(1): 192, 2018 11 08.
Article in English | MEDLINE | ID: mdl-30409154

ABSTRACT

CRISPR/dCas9 is a versatile tool that can be used to recruit various effectors and fluorescent molecules to defined genome regions where it can modulate genetic and epigenetic markers, or track the chromatin dynamics in live cells. In vivo applications of CRISPR/dCas9 in animals have been challenged by delivery issues. We generate and characterize a mouse strain with dCas9-EGFP ubiquitously expressed in various tissues. Studying telomere dynamics in these animals reveals surprising results different from those observed in cultured cell lines. The CRISPR/dCas9 knock-in mice provide an important and versatile tool to mechanistically study genome functions in live animals.


Subject(s)
CRISPR-Cas Systems , Genome , Green Fluorescent Proteins/metabolism , Hepatocytes/metabolism , Molecular Imaging/methods , Telomere/metabolism , Animals , Cells, Cultured , Green Fluorescent Proteins/genetics , HEK293 Cells , Hep G2 Cells , Hepatocytes/cytology , Humans , Image Processing, Computer-Assisted , Mice , Mice, Inbred C57BL , Telomere/genetics
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