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1.
Sci Rep ; 9(1): 10602, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31332247

RESUMO

Postoperative ileus (POI) is an intestinal dysmotility frequently occurring after abdominal surgery. An orchestrated neuroimmune response within the muscularis externa (ME) involves activation of resident macrophages, enteric glia and infiltration of blood-derived leukocytes. Interleukin-1 receptor type-I (IL1R1) signalling on enteric glia has been shown to be involved in POI development. Herein we investigated the distinct role of the IL1R1 ligands interleukin (IL) -1α and IL-1ß and focused on the mechanism of IL-1ß production. IL-1α and IL-1ß deficient mice were protected from POI. Bone-marrow transplantation studies indicated that IL-1α originated from radio-resistant cells while IL-1ß was released from the radio-sensitive infiltrating leukocytes. Mouse strains deficient in inflammasome formation identified the absent in melanoma 2 (AIM2) inflammasome to be crucial for IL-1ß production in POI. Mechanistically, antibiotic-treated mice revealed a prominent role of the microbiome in IL-1ß production. Our study provides new insights into distinct roles of IL-1α and IL-1ß signalling during POI. While IL-1α release is most likely an immediate passive response to the surgical trauma, IL-1ß production depends on AIM2 inflammasome formation and the microbiome. Selective interaction in this pathway might be a promising target to prevent POI in surgical patients.

2.
EMBO J ; 38(13): e100926, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31268602

RESUMO

The guanylate binding protein (GBP) family of interferon-inducible GTPases promotes antimicrobial immunity and cell death. During bacterial infection, multiple mouse Gbps, human GBP2, and GBP5 support the activation of caspase-1-containing inflammasome complexes or caspase-4 which trigger pyroptosis. Whether GBPs regulate other forms of cell death is not known. The apicomplexan parasite Toxoplasma gondii causes macrophage death through unidentified mechanisms. Here we report that Toxoplasma-induced death of human macrophages requires GBP1 and its ability to target Toxoplasma parasitophorous vacuoles through its GTPase activity and prenylation. Mechanistically, GBP1 promoted Toxoplasma detection by AIM2, which induced GSDMD-independent, ASC-, and caspase-8-dependent apoptosis. Identical molecular determinants targeted GBP1 to Salmonella-containing vacuoles. GBP1 facilitated caspase-4 recruitment to Salmonella leading to its enhanced activation and pyroptosis. Notably, GBP1 could be bypassed by the delivery of Toxoplasma DNA or bacterial LPS into the cytosol, pointing to its role in liberating microbial molecules. GBP1 thus acts as a gatekeeper of cell death pathways, which respond specifically to infecting microbes. Our findings expand the immune roles of human GBPs in regulating not only pyroptosis, but also apoptosis.

3.
Cancer Immunol Res ; 7(8): 1258-1266, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31239318

RESUMO

Multiple studies have associated the transcription factor IRF1 with tumor-suppressive activities. Here, we report an opposite tumor cell-intrinsic function of IRF1 in promoting tumor growth. IRF1-deficient tumor cells showed reduced tumor growth in MC38 and CT26 colon carcinoma and B16 melanoma mouse models. This reduction in tumor growth was dependent on host CD8+ T cells. Detailed profiling of tumor-infiltrating leukocytes did not show changes in the various T-cell and myeloid cell populations. However, CD8+ T cells that had infiltrated IRF1-deficieint tumors in vivo exhibited enhanced cytotoxicity. IRF1-deficient tumor cells lost the ability to upregulate PD-L1 expression in vitro and in vivo and were more susceptible to T-cell-mediated killing. Induced expression of PD-L1 in IRF1-deficient tumor cells restored tumor growth. These results indicate differential activity of IRF1 in tumor escape.

4.
Nat Struct Mol Biol ; 26(5): 361-371, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31061526

RESUMO

Histone lysine methylation is generally performed by SET domain methyltransferases and regulates chromatin structure and gene expression. Here, we identify human C21orf127 (HEMK2, N6AMT1, PrmC), a member of the seven-ß-strand family of putative methyltransferases, as a novel histone lysine methyltransferase. C21orf127 functions as an obligate heterodimer with TRMT112, writing the methylation mark on lysine 12 of histone H4 (H4K12) in vitro and in vivo. We characterized H4K12 recognition by solving the crystal structure of human C21orf127-TRMT112, hereafter termed 'lysine methyltransferase 9' (KMT9), in complex with S-adenosyl-homocysteine and H4K12me1 peptide. Additional analyses revealed enrichment for KMT9 and H4K12me1 at the promoters of numerous genes encoding cell cycle regulators and control of cell cycle progression by KMT9. Importantly, KMT9 depletion severely affects the proliferation of androgen receptor-dependent, as well as that of castration- and enzalutamide-resistant prostate cancer cells and xenograft tumors. Our data link H4K12 methylation with KMT9-dependent regulation of androgen-independent prostate tumor cell proliferation, thereby providing a promising paradigm for the treatment of castration-resistant prostate cancer.

5.
J Exp Med ; 216(7): 1700-1723, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126966

RESUMO

The RNase Regnase-1 is a master RNA regulator in macrophages and T cells that degrades cellular and viral RNA upon NF-κB signaling. The roles of its family members, however, remain largely unknown. Here, we analyzed Regnase-3-deficient mice, which develop hypertrophic lymph nodes. We used various mice with immune cell-specific deletions of Regnase-3 to demonstrate that Regnase-3 acts specifically within myeloid cells. Regnase-3 deficiency systemically increased IFN signaling, which increased the proportion of immature B and innate immune cells, and suppressed follicle and germinal center formation. Expression analysis revealed that Regnase-3 and Regnase-1 share protein degradation pathways. Unlike Regnase-1, Regnase-3 expression is high specifically in macrophages and is transcriptionally controlled by IFN signaling. Although direct targets in macrophages remain unknown, Regnase-3 can bind, degrade, and regulate mRNAs, such as Zc3h12a (Regnase-1), in vitro. These data indicate that Regnase-3, like Regnase-1, is an RNase essential for immune homeostasis but has diverged as key regulator in the IFN pathway in macrophages.

6.
Nat Rev Immunol ; 19(3): 141-153, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30644449

RESUMO

The immune system detects disturbances in homeostasis that occur during infection, sterile tissue damage and cancer. This initiates immune responses that seek to eliminate the trigger of immune activation and to re-establish homeostasis. At the same time, these mechanisms can also play a crucial role in the progression of disease. The occurrence of DNA in the cytosol constitutes a potent trigger for the innate immune system, governing the production of key inflammatory cytokines such as type I interferons and IL-1ß. More recently, it has become clear that cytosolic DNA also triggers other biological responses, including various forms of programmed cell death. In this article, we review the emerging literature on the pathways governing DNA-stimulated cell death and the current knowledge on how these processes shape immune responses to exogenous and endogenous challenges.

7.
Proc Natl Acad Sci U S A ; 116(3): 970-975, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30591564

RESUMO

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is a critical regulator of cell death and inflammation, but its relevance for human disease pathogenesis remains elusive. Studies of monogenic disorders might provide critical insights into disease mechanisms and therapeutic targeting of RIPK1 for common diseases. Here, we report on eight patients from six unrelated pedigrees with biallelic loss-of-function mutations in RIPK1 presenting with primary immunodeficiency and/or intestinal inflammation. Mutations in RIPK1 were associated with reduced NF-κB activity, defective differentiation of T and B cells, increased inflammasome activity, and impaired response to TNFR1-mediated cell death in intestinal epithelial cells. The characterization of RIPK1-deficient patients highlights the essential role of RIPK1 in controlling human immune and intestinal homeostasis, and might have critical implications for therapies targeting RIPK1.


Assuntos
Diferenciação Celular , Imunidade nas Mucosas/genética , Doenças Inflamatórias Intestinais , Mucosa Intestinal , Proteína Serina-Treonina Quinases de Interação com Receptores , Imunodeficiência Combinada Severa , Linfócitos B/imunologia , Linfócitos B/patologia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Células Epiteliais/imunologia , Células Epiteliais/patologia , Feminino , Células HCT116 , Células HEK293 , Humanos , Doenças Inflamatórias Intestinais/genética , Doenças Inflamatórias Intestinais/imunologia , Doenças Inflamatórias Intestinais/patologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/patologia , Masculino , Mutação , NF-kappa B/genética , NF-kappa B/imunologia , Proteína Serina-Treonina Quinases de Interação com Receptores/deficiência , Proteína Serina-Treonina Quinases de Interação com Receptores/imunologia , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/imunologia , Imunodeficiência Combinada Severa/patologia , Linfócitos T/imunologia , Linfócitos T/patologia
8.
J Gen Virol ; 100(2): 278-288, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30566072

RESUMO

A first step towards the development of a human immunodeficiency virus (HIV) animal model has been the identification and surmounting of species-specific barriers encountered by HIV along its replication cycle in cells from small animals. Serine incorporator proteins 3 (SERINC3) and 5 (SERINC5) were recently identified as restriction factors that reduce HIV-1 infectivity. Here, we compared the antiviral activity of SERINC3 and SERINC5 among mice, rats and rabbits, and their susceptibility to viral counteraction to their human counterparts. In the absence of viral antagonists, rodent and lagomorph SERINC3 and SERINC5 displayed anti-HIV activity in a similar range to human controls. Vesicular stomatitis virus G protein (VSV-G) pseudotyped virions were considerably less sensitive to restriction by all SERINC3/5 orthologs. Interestingly, HIV-1 Nef, murine leukemia virus (MLV) GlycoGag and equine infectious anemia virus (EIAV) S2 counteracted the antiviral activity of all SERINC3/5 orthologs with similar efficiency. Our results demonstrate that the antiviral activity of SERINC3/5 proteins is conserved in rodents and rabbits, and can be overcome by all three previously reported viral antagonists.


Assuntos
HIV-1/crescimento & desenvolvimento , HIV-1/imunologia , Interações Hospedeiro-Patógeno , Fatores Imunológicos/metabolismo , Produtos do Gene nef do Vírus da Imunodeficiência Humana/metabolismo , Animais , Vetores Genéticos , Camundongos , Coelhos , Ratos , Vesiculovirus/genética , Vesiculovirus/crescimento & desenvolvimento
9.
Cell Rep ; 25(9): 2354-2368.e5, 2018 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-30485805

RESUMO

IL-1ß is a cytokine of pivotal importance to the orchestration of inflammatory responses. Synthesized as an inactive pro-cytokine, IL-1ß requires proteolytic maturation to gain biological activity. Here, we identify intrinsic apoptosis as a non-canonical trigger of IL-1ß maturation. Guided by the discovery of the immunomodulatory activity of vioprolides, cyclic peptides isolated from myxobacteria, we observe IL-1ß maturation independent of canonical inflammasome pathways, yet dependent on intrinsic apoptosis. Mechanistically, vioprolides inhibit MCL-1 and BCL2, which in turn triggers BAX/BAK-dependent mitochondrial outer membrane permeabilization (MOMP). Induction of MOMP results in the release of pro-apoptotic factors initiating intrinsic apoptosis, as well as the depletion of IAPs (inhibitors of apoptosis proteins). IAP depletion, in turn, operates upstream of ripoptosome complex formation, subsequently resulting in caspase-8-dependent IL-1ß maturation. These results establish the ripoptosome/caspase-8 complex as a pro-inflammatory checkpoint that senses the perturbation of mitochondrial integrity.

10.
Gastroenterology ; 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30267714

RESUMO

Caspase-8 (CASP8) is a protease that initiates apoptosis and regulates inflammation and immune responses. We identified germline mutations in CASP8 in 3 unrelated patients with infant-onset inflammatory bowel disease: 2 patients were homozygous for the mutation 710A>G, p.Q237R, which resulted in reduced protein expression, and 1 patient carried the mutation 793C>T, p.R265W. We isolated peripheral blood mononuclear cells from our index patient and observed defects in T- and B-cell maturation, proliferation, and/or activation. Macrophages from 1 patient with CASP8 deficiency and monocytic BLaER1 cells with knockout of CASP8 or overexpression of CASP8 with the 710A>G mutation had altered inflammasome activity on stimulation with lipopolysaccharide. Patient-derived intestinal organoids and colon carcinoma cells with knockout of CASP8 had defects in cell death processes that involved loss of TRAIL signaling and increased necroptosis. These findings indicate that CASP8 controls inflammation, innate and adaptive immunity, and intestinal barrier integrity in humans.

11.
Dev Cell ; 46(5): 530-532, 2018 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-30205036

RESUMO

The role of mitochondria as a signaling platform downstream of the RNA sensors RIG-I and MDA5 is well defined. Now, a recent study in Nature by Dhir et al. (2018) identifies mitochondrial dsRNA as an immunogenic ligand, adding another intriguing aspect to the role of mitochondria in innate immunity.


Assuntos
RNA Helicases DEAD-box/genética , Helicase IFIH1 Induzida por Interferon , Imunidade Inata , Mitocôndrias , RNA de Cadeia Dupla
12.
ACS Chem Biol ; 13(10): 2981-2988, 2018 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-30183250

RESUMO

A Natural Compound Library containing myxobacterial secondary metabolites was screened in murine macrophages for novel activators of IL-1ß maturation and secretion. The most potent of three hits in total was a so far undescribed metabolite, which was identified from the myxobacterium Hyalangium minutum strain Hym3. While the planar structure of 1 was elucidated by high resolution mass spectrometry and NMR data yielding an asymmetric boron containing a macrodiolide core structure, its relative stereochemistry of all 20 stereocenters of the 42-membered ring was assigned by rotating frame Overhause effect spectroscopy correlations, 1H,1H, and 1H,13C coupling constants, and by comparison of 13C chemical shifts to those of the structurally related metabolites tartrolon B-D. The absolute stereochemistry was subsequently assigned by Mosher's and Marfey's methods. Further functional studies revealed that hyaboron and other boronated natural compounds resulted in NLRP3 inflammasome dependent IL-1ß maturation, which is most likely due to their ability to act as potassium ionophores. Moreover, besides its inflammasome-stimulatory activity in human and mouse cells, hyaboron (1) showed additional diverse biological activities, including antibacterial and antiparasitic effects.

13.
PLoS One ; 13(8): e0202364, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30092044

RESUMO

[This corrects the article DOI: 10.1371/journal.pone.0131702.].

14.
Blood Adv ; 2(6): 691-702, 2018 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-29581108

RESUMO

Vitamin K reduction is catalyzed by 2 enzymes in vitro: the vitamin K 2,3-epoxide reductase complex subunit 1 (VKORC1) and its isozyme VKORC1-like1 (VKORC1L1). In vivo, VKORC1 reduces vitamin K to sustain γ-carboxylation of vitamin K-dependent proteins, including coagulation factors. Inhibition of VKORC1 by oral anticoagulants (OACs) is clinically used in therapy and in prevention of thrombosis. However, OACs also inhibit VKORC1L1, which was previously shown to play a role in intracellular redox homeostasis in vitro. Here, we report data for the first time on specific inhibition of both VKOR enzymes for various OACs and rodenticides examined in a cell-based assay. Effects on endogenous VKORC1 and VKORC1L1 were independently investigated in genetically engineered HEK 293T cells that were knocked out for the respective genes by CRISPR/Cas9 technology. In general, dose-responses for 4-hydroxycoumarins and 1,3-indandiones were enzyme-dependent, with lower susceptibility for VKORC1L1 compared with VKORC1. In contrast, rodenticides exhibited nearly identical dose-responses for both enzymes. To explain the distinct inhibition pattern, we performed in silico modeling suggesting different warfarin binding sites for VKORC1 and VKORC1L1. We identified arginine residues at positions 38, 42, and 68 in the endoplasmatic reticulum luminal loop of VKORC1L1 responsible for charge-stabilized warfarin binding, resulting in a binding pocket that is diametrically opposite to that of VKORC1. In conclusion, our findings provide insight into structural and molecular drug binding on VKORC1, and especially on VKORC1L1.

15.
J Mol Biol ; 430(2): 133-141, 2018 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-29203171

RESUMO

NLRP3 is the most studied inflammasome sensor due to its crucial involvement in sterile and infection-triggered inflammation. Although its molecular mode of activation remains to be defined, it is well established that low intracellular potassium concentrations result in its activation. This functionality allows the classical NLRP3 pathway to serve as a highly sensitive, but non-specific surveillance mechanism responding to any type of perturbation that breaches plasma membrane integrity and the associated potassium gradient across the membrane. Here, we review our current knowledge on potassium efflux-dependent NLRP3 activation, with a special focus on how major cell death programs are rendered pro-inflammatory by secondary NLRP3 activation. Apart from the "alternative inflammasome" as the major exception to the rule, this connection explains the fundamental importance of NLRP3 in cell death-associated inflammation and firmly establishes NLRP3 as a principal surveillance mechanism of cellular integrity.

16.
Methods Mol Biol ; 1714: 57-66, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29177855

RESUMO

Monocytes and macrophages play a pivotal role in the induction and shaping of immune responses. Expressing a broad array of pattern recognition receptors (PRRs), monocytes and macrophages constitute an integral component of the innate branch of the immune system. Traditionally, the majority of innate immune sensing and signaling pathways have been studied in macrophages of the murine system. This is largely due to the fact that genetic loss-of-function studies are amenable in this species. On the other hand, human cell lines of the monocyte-macrophage cell lineage have been widely used to study myeloid cells in vitro. However, commonly utilized models (e.g., THP-1 cells) only mimic a limited spectrum of the immunobiology of primary human myeloid cells. Recently, we have explored the possibility to fill this gap with a human trans-differentiation cell culture system, in which lineage conversion from malignant B-lineage cells to monocytes/macrophages is caused by the inducible nuclear translocation of a C/EBPα transgene, BLaER1 cells. Using this model, we were able to characterize a novel inflammasome signaling entity that could not have been uncovered in the murine system or THP-1 cells. Here, we describe the handling of BLaER1 cells, providing a detailed protocol for their induced trans-differentiation. We also provide data to demonstrate the applicability of the BLaER1 monocyte/macrophage system to study phagocytosis and various PRR cascades in human cells.


Assuntos
Diferenciação Celular , Macrófagos/citologia , Modelos Biológicos , Monócitos/citologia , Proteínas Estimuladoras de Ligação a CCAAT/genética , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Linhagem Celular , Humanos , Imunidade Inata , Macrófagos/metabolismo , Monócitos/metabolismo , Células Mieloides/citologia , Células Mieloides/metabolismo , Transdução de Sinais
17.
Genes Immun ; 2017 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-29217828

RESUMO

We selected two sets of naturally occurring human missense allelic variants within innate immune genes. The first set represented eleven non-synonymous variants in six different genes involved in interferon (IFN) induction, present in a cohort of patients suffering from herpes simplex encephalitis (HSE) and the second set represented sixteen allelic variants of the IFNLR1 gene. We recreated the variants in vitro and tested their effect on protein function in a HEK293T cell based assay. We then used an array of 14 available bioinformatics tools to predict the effect of these variants upon protein function. To our surprise two of the most commonly used tools, CADD and SIFT, produced a high rate of false positives, whereas SNPs&GO exhibited the lowest rate of false positives in our test. As the problem in our test in general was false positive variants, inclusion of mutation significance cutoff (MSC) did not improve accuracy.

18.
Cell ; 171(5): 1110-1124.e18, 2017 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-29033128

RESUMO

Detection of cytosolic DNA constitutes a central event in the context of numerous infectious and sterile inflammatory conditions. Recent studies have uncovered a bipartite mode of cytosolic DNA recognition, in which the cGAS-STING axis triggers antiviral immunity, whereas AIM2 triggers inflammasome activation. Here, we show that AIM2 is dispensable for DNA-mediated inflammasome activation in human myeloid cells. Instead, detection of cytosolic DNA by the cGAS-STING axis induces a cell death program initiating potassium efflux upstream of NLRP3. Forward genetics identified regulators of lysosomal trafficking to modulate this cell death program, and subsequent studies revealed that activated STING traffics to the lysosome, where it triggers membrane permeabilization and thus lysosomal cell death (LCD). Importantly, the cGAS-STING-NLRP3 pathway constitutes the default inflammasome response during viral and bacterial infections in human myeloid cells. We conclude that targeting the cGAS-STING-LCD-NLRP3 pathway will ameliorate pathology in inflammatory conditions that are associated with cytosolic DNA sensing.


Assuntos
Morte Celular , Inflamassomos/metabolismo , Monócitos/citologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , DNA/metabolismo , Humanos , Proteínas de Membrana/metabolismo , Monócitos/metabolismo , Transdução de Sinais
19.
Cell Rep ; 21(3): 578-586, 2017 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-29045828

RESUMO

Regulatory T cells (Tregs) prevent autoimmunity but limit antitumor immunity. The canonical NF-κB signaling pathway both activates immunity and promotes thymic Treg development. Here, we report that mature Tregs continue to require NF-κB signaling through IκB-kinase ß (IKKß) after thymic egress. Mice lacking IKKß in mature Tregs developed scurfy-like immunopathology due to death of peripheral FoxP3+ Tregs. Also, pharmacological IKKß inhibition reduced Treg numbers in the circulation by ∼50% and downregulated FoxP3 and CD25 expression and STAT5 phosphorylation. In contrast, activated cytotoxic T lymphocytes (CTLs) were resistant to IKKß inhibition because other pathways, in particular nuclear factor of activated T cells (NFATc1) signaling, sustained their survival and expansion. In a melanoma mouse model, IKKß inhibition after CTL cross-priming improved the antitumor response and delayed tumor growth. In conclusion, prolonged IKKß inhibition decimates circulating Tregs and improves CTL responses when commenced after tumor vaccination, indicating that IKKß represents a druggable checkpoint.


Assuntos
Quinase I-kappa B/antagonistas & inibidores , Neoplasias/enzimologia , Neoplasias/imunologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Reguladores/imunologia , Animais , Apresentação Cruzada/imunologia , Homeostase , Quinase I-kappa B/metabolismo , Ativação Linfocitária/imunologia , Camundongos , Fatores de Transcrição NFATC/metabolismo , Fenótipo , Transdução de Sinais , Vacinação
20.
Nature ; 549(7672): 394-398, 2017 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-28902841

RESUMO

Cytosolic DNA arising from intracellular pathogens triggers a powerful innate immune response. It is sensed by cyclic GMP-AMP synthase (cGAS), which elicits the production of type I interferons by generating the second messenger 2'3'-cyclic-GMP-AMP (cGAMP). Endogenous nuclear or mitochondrial DNA can also be sensed by cGAS under certain conditions, resulting in sterile inflammation. The cGAS dimer binds two DNA ligands shorter than 20 base pairs side-by-side, but 20-base-pair DNA fails to activate cGAS in vivo and is a poor activator in vitro. Here we show that cGAS is activated in a strongly DNA length-dependent manner both in vitro and in human cells. We also show that cGAS dimers form ladder-like networks with DNA, leading to cooperative sensing of DNA length: assembly of the pioneering cGAS dimer between two DNA molecules is ineffective; but, once formed, it prearranges the flanking DNA to promote binding of subsequent cGAS dimers. Remarkably, bacterial and mitochondrial nucleoid proteins HU and mitochondrial transcription factor A (TFAM), as well as high-mobility group box 1 protein (HMGB1), can strongly stimulate long DNA sensing by cGAS. U-turns and bends in DNA induced by these proteins pre-structure DNA to nucleate cGAS dimers. Our results suggest a nucleation-cooperativity-based mechanism for sensitive detection of mitochondrial DNA and pathogen genomes, and identify HMGB/TFAM proteins as DNA-structuring host factors. They provide an explanation for the peculiar cGAS dimer structure and suggest that cGAS preferentially binds incomplete nucleoid-like structures or bent DNA.


Assuntos
Proteínas de Ligação a DNA/metabolismo , DNA/química , DNA/metabolismo , Proteínas HMGB/metabolismo , Proteínas de Grupo de Alta Mobilidade/metabolismo , Proteínas Mitocondriais/metabolismo , Nucleotidiltransferases/metabolismo , Fatores de Transcrição/metabolismo , Animais , Linhagem Celular , Feminino , Humanos , Camundongos , Modelos Moleculares , Conformação de Ácido Nucleico , Nucleotídeos Cíclicos/metabolismo , Nucleotidiltransferases/química , Multimerização Proteica
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