Neadaptivní imunitní systém je první obranou organismu při jeho napadení patogenem. Signalizační cesta cGAS -cGAMP -STING je součástí tohoto systému a je zcela klíčová při obraně proti DNA virům a retrovirům Zároveň je chronické vybuzení této kaskády pravděpodobnou příčinou některých autoimunitních onemocnění. Studium této signalizační cesty je klíčové pro vývoj terapeutik virových a autoimunitních onemocnění.

The innate immune system is the first line of defence of organism against pathogens. As a part of innate immune system, cGAS -cGAMP- -STING signaling pathway takes a crucial part in immune response to DNA viruses and retroviruses. In contrast, chronic activation of this pathway is probably cause of some autoimmune diseases. Studium of this signaling pathway is crucial for new antiviral and immunosupresive drugs development.

• Klíčová slova
• cGAS-cGAMP-STING,
• MeSH
• DNA viry * imunologie   MeSH
• DNA genetika   chemie   imunologie   MeSH
• fosforylace MeSH
• interferon typ I * metabolismus   MeSH
• lidé MeSH
• přirozená imunita * MeSH
• receptor interferonu alfa-beta * MeSH
• receptory rozpoznávající vzory MeSH
• Retroviridae * imunologie   MeSH
• signální transdukce * MeSH
• ubikvitiny metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

Sensing of cytoplasmic DNA by cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) synthase (cGAS) results in production of the dinucleotide cGAMP and consecutive activation of stimulator of interferon genes (STING) followed by production of type I interferon (IFN). Although cancer cells contain supra-normal concentrations of cytoplasmic DNA, they rarely produce type I IFN spontaneously. This suggests that defects in the DNA-sensing pathway may serve as an immune escape mechanism. We find that cancer cells produce cGAMP that is transferred via gap junctions to tumor-associated dendritic cells (DCs) and macrophages, which respond by producing type I IFN in situ. Cancer-cell-intrinsic expression of cGAS, but not STING, promotes infiltration by effector CD8+ T cells and consequently results in prolonged survival. Furthermore, cGAS-expressing cancers respond better to genotoxic treatments and immunotherapy. Thus, cancer-cell-derived cGAMP is crucial to protective anti-tumor CD8+ T cell immunity. Consequently, cancer-cell-intrinsic expression of cGAS determines tumor immunogenicity and makes tumors hot. These findings are relevant for genotoxic and immune therapies for cancer.

• MeSH
• CD8-pozitivní T-lymfocyty imunologie   MeSH
• dendritické buňky metabolismus   MeSH
• imunoterapie MeSH
• interferon typ I metabolismus   MeSH
• lidé MeSH
• membránové proteiny MeSH
• mikrosatelitní repetice genetika   MeSH
• myši inbrední C57BL MeSH
• nádorové buněčné linie MeSH
• nádory farmakoterapie   imunologie   patologie   MeSH
• nukleotidy cyklické metabolismus   MeSH
• nukleotidyltransferasy metabolismus   MeSH
• poškození DNA MeSH
• progrese nemoci MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Monkeypox, or mpox, is a disease that has recently resurfaced and spread across the globe. Despite the availability of an FDA-approved vaccine (JYNNEOS) and an effective drug (tecovirimat), concerns remain over the possible recurrence of a viral pandemic. Like any other virus, mpox virus must overcome the immune system to replicate. Viruses have evolved various strategies to overcome both innate and adaptive immunity. Poxviruses possess an unusual nuclease, poxin, which cleaves 2'-3'-cGAMP, a cyclic dinucleotide, which is an important second messenger in the cGAS-STING signaling pathway. Here, we present the crystal structure of mpox poxin. The structure reveals a conserved, predominantly β-sheet fold and highlights the high conservation of the cGAMP binding site and of the catalytic residues His17, Tyr138, and Lys142. This research suggests that poxin inhibitors could be effective against multiple poxviruses.

• MeSH
• lidé MeSH
• opičí neštovice * MeSH
• Poxviridae * MeSH
• racionální návrh léčiv MeSH
• signální transdukce MeSH
• virus opičích neštovic MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Human stimulator of interferon genes (hSTING) is a signaling adaptor protein that triggers innate immune system by response to cytosolic DNA and second messenger cyclic dinucleotides (CDNs). Natural CDNs contain purine nucleobase with different phosphodiester linkage types (3'-3', 2'-2' or mixed 2'-3'-linkages) and exhibit different binding affinity towards hSTING, ranging from micromolar to nanomolar. High-affinity CDNs are considered as suitable candidates for treatment of chronic hepatitis B and cancer. We have used molecular dynamics simulations to investigate dynamical aspects of binding of natural CDNs (specifically, 2'-2'-cGAMP, 2'-3'-cGAMP, 3'-3'-cGAMP, 3'-3'-c-di-AMP, and 3'-3'-c-di-GMP) with hSTINGwt protein. Our results revealed that CDN/hSTINGwt interactions are controlled by the balance between fluctuations (conformational changes) in the CDN ligand and the protein dynamics. Binding of different CDNs induces different degrees of conformational/dynamics changes in hSTINGwt ligand binding cavity, especially in α1-helices, the so-called lid region and α2-tails. The ligand residence time in hSTINGwt protein pocket depends on different contribution of R232 and R238 residues interacting with oxygen atoms of phosphodiester groups in ligand, water distribution around interacting charged centers (in protein residues and ligand) and structural stability of closed conformation state of hSTINGwt protein. These findings may perhaps guide design of new compounds modulating hSTING activity.Communicated by Ramaswamy H. Sarma.

• MeSH
• dinukleosidfosfáty * chemie   MeSH
• DNA MeSH
• lidé MeSH
• ligandy MeSH
• oligonukleotidy MeSH
• simulace molekulární dynamiky * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Vascularized composite allografts (VCAs) of faces and extremities are subject to chronic rejection that is incompletely understood. Here we report on immunoproteomic evaluation of a full facial VCA removed 88 months after transplantation due to chronic rejection. CD8-positive T cells of donor (graft) origin infiltrate deep intragraft arteries in apposition to degenerating endothelium of chimeric recipient origin in association with arteriosclerotic alterations. Digital spatial proteomic profiling highlighted proteins expressed by activated cytotoxic T cells and macrophages as well as pathway components involved in atherogenic responses, including Indoleamine 2,3-Dioxygenase 1 (IDO1) and Stimulator of Interferon Response CGAMP Interactor (STING). Chronic facial VCA rejection thus involves T cell/macrophage-mediated accelerated arteriosclerosis not normally represented in punch biopsies and potentially driven by persistent graft-resident effector T cells and recipient target endothelium that chimerically repopulates graft arteries.

• MeSH
• přežívání štěpu MeSH
• proteomika MeSH
• rejekce štěpu etiologie   patologie   MeSH
• štěpy z kompozitní tkáně * transplantace   MeSH
• transplantace obličeje * MeSH
• vaskularizovaná kompozitní alotransplantace * MeSH
• Publikační typ
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Cyclic dinucleotides (CDNs) are second messengers that activate stimulator of interferon genes (STING). The cGAS-STING pathway plays a promising role in cancer immunotherapy. Here, we describe the synthesis of CDNs containing 7-substituted 7-deazapurine moiety. We used mouse cyclic GMP-AMP synthase and bacterial dinucleotide synthases for the enzymatic synthesis of CDNs. Alternatively, 7-(het)aryl 7-deazapurine CDNs were prepared by Suzuki-Miyaura cross-couplings. New CDNs were tested in biochemical and cell-based assays for their affinity to human STING. Eight CDNs showed better activity than 2'3'-cGAMP, the natural ligand of STING. The effect on cytokine and chemokine induction was also evaluated. The best activities were observed for CDNs bearing large aromatic substituents that point above the CDN molecule. We solved four X-ray structures of complexes of new CDNs with human STING. We observed π-π stacking interactions between the aromatic substituents and Tyr240 that are involved in the stabilization of CDN-STING complexes.

• MeSH
• cytokiny MeSH
• interferony MeSH
• lidé MeSH
• ligandy MeSH
• membránové proteiny * metabolismus   MeSH
• myši MeSH
• nukleotidy cyklické * chemie   MeSH
• nukleotidyltransferasy MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH