Irena Zentsova1, Zuzana Parackova2, Jana Kayserova2, Lenka Palova-Jelinkova3, Petra Vrabcova2, Nikol Volfova4, Zdenek Sumnik5, Stepanka Pruhova5, Lenka Petruzelkova5, Anna Sediva2. 1. Department of Immunology, 2nd Faculty of Medicine, Charles University, University Hospital in Motol, Prague, Czech Republic. Electronic address: irena.zentsova@fnmotol.cz. 2. Department of Immunology, 2nd Faculty of Medicine, Charles University, University Hospital in Motol, Prague, Czech Republic. 3. Sotio a.c., Prague, Czech Republic. 4. Department of Paediatrics and Adolescent Medicine, 1st Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic. 5. Department of Pediatrics, 2nd Faculty of Medicine, Charles University, University Hospital in Motol, Prague, Czech Republic.
Abstract
BACKGROUND: The aberrant recognition of self-nucleic acids by the innate immune system contributes to the pathology of several autoimmune diseases. Although microbial DNA and, in certain instances, self-DNA that is released from damaged cells are primarily recognized by Toll-like receptor 9 (TLR9), recent evidence suggests that other cytosolic sequence-nonspecific DNA sensors contribute to DNA recognition. In this study, we focused on the sensing of microbial and host DNA in type 1 diabetes (T1D) patients. METHODS: Peripheral blood mononuclear cells (PBMCs) and monocytes from pediatric patients with T1D and from healthy donors were stimulated with microbial DNA (CpG) or with self-DNA (DNA contained within neutrophil extracellular traps, NETs). The production of cytokines was measured by flow cytometry and multiplex bead assays. The internalization of microbial DNA and its colocalization with STING was detected by image cytometry. Furthermore, the involvement of the TBK1 kinase was investigated by detecting its phosphorylation with phospho-flow cytometry or by using a TBK1 inhibition assay. RESULTS: We observed a prominent proinflammatory response in T1D PBMCs, especially pDCs and monocytes, to microbial DNA in comparison to that in controls. We further confirmed that monocytes could bind and internalize DNA and respond by releasing proinflammatory cytokines in a more pronounced manner in T1D patients than those in controls. Surprisingly, this cytokine production was not affected by TLR9 blockade, suggesting the involvement of intracellular receptors in DNA recognition. We further identified TBK1 and STING as two crucial molecules in the DNA-sensing pathway that were involved in CpG-DNA sensing by T1D cells. A similar DNA-sensing pathway that was dependent on intracellular DNA sensors and the STING-TBK1 interaction was employed in response to NETs, which were used to model self-DNA. CONCLUSIONS: Here, we show that there were significant differences in DNA sensing in T1D patients compared to that in controls. We demonstrate that monocytes from T1D patients are able to sense microbial- and self-DNA, leading to proinflammatory cytokine secretion through the adaptor protein STING and the TBK1 kinase.
BACKGROUND: The aberrant recognition of self-nucleic acids by the innate immune system contributes to the pathology of several autoimmune diseases. Although microbial DNA and, in certain instances, self-DNA that is released from damaged cells are primarily recognized by Toll-like receptor 9 (TLR9), recent evidence suggests that other cytosolic sequence-nonspecific DNA sensors contribute to DNA recognition. In this study, we focused on the sensing of microbial and host DNA in type 1 diabetes (T1D) patients. METHODS: Peripheral blood mononuclear cells (PBMCs) and monocytes from pediatric patients with T1D and from healthy donors were stimulated with microbial DNA (CpG) or with self-DNA (DNA contained within neutrophil extracellular traps, NETs). The production of cytokines was measured by flow cytometry and multiplex bead assays. The internalization of microbial DNA and its colocalization with STING was detected by image cytometry. Furthermore, the involvement of the TBK1 kinase was investigated by detecting its phosphorylation with phospho-flow cytometry or by using a TBK1 inhibition assay. RESULTS: We observed a prominent proinflammatory response in T1D PBMCs, especially pDCs and monocytes, to microbial DNA in comparison to that in controls. We further confirmed that monocytes could bind and internalize DNA and respond by releasing proinflammatory cytokines in a more pronounced manner in T1D patients than those in controls. Surprisingly, this cytokine production was not affected by TLR9 blockade, suggesting the involvement of intracellular receptors in DNA recognition. We further identified TBK1 and STING as two crucial molecules in the DNA-sensing pathway that were involved in CpG-DNA sensing by T1D cells. A similar DNA-sensing pathway that was dependent on intracellular DNA sensors and the STING-TBK1 interaction was employed in response to NETs, which were used to model self-DNA. CONCLUSIONS: Here, we show that there were significant differences in DNA sensing in T1D patients compared to that in controls. We demonstrate that monocytes from T1D patients are able to sense microbial- and self-DNA, leading to proinflammatory cytokine secretion through the adaptor protein STING and the TBK1 kinase.
Authors: Zuzana Parackova; Tomas Milota; Petra Vrabcova; Jitka Smetanova; Michael Svaton; Tomas Freiberger; Veronika Kanderova; Anna Sediva Journal: Cell Death Dis Date: 2020-06-08 Impact factor: 8.469
Authors: Z Parackova; P Vrabcova; I Zentsova; J Kayserova; I Richtrova; L Sojka; K Stechova; Z Sumnik; A Sediva Journal: Sci Rep Date: 2020-01-16 Impact factor: 4.379
Authors: Zuzana Parackova; Irena Zentsova; Marketa Bloomfield; Petra Vrabcova; Jitka Smetanova; Adam Klocperk; Grigorij Mesežnikov; Luis Fernando Casas Mendez; Tomas Vymazal; Anna Sediva Journal: Cells Date: 2020-09-29 Impact factor: 6.600