| 1. |
- Berggren, Olof, et al.
(författare)
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Activation of plasmacytoid dendritic cells and B cells with two structurally different Toll-like receptor 7 agonists
- 2020
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 91:6
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic Toll-like receptor (TLR) 7 agonists have been suggested as immune modulators in a range of conditions. In contrast, self-derived TLR7 activators, such as RNA-containing immune complexes (RNA-IC), can contribute to autoimmune diseases due to endogenous immune activation. The exact difference in immune cell response between synthetic and endogenous TLR7 triggers is only partly known. An understanding of these differences could aid in the development of new therapeutic agents and provide insights into autoimmune disease mechanisms. We therefore compared the stimulatory capacity of two TLR7 agonists, RNA-IC and a synthetic small molecule DSR-6434, on blood leucocytes, plasmacytoid dendritic cells (pDCs) and B cells from healthy individuals. IFN-α, IL-6, IL-8 and TNF levels were measured by immunoassays, and gene expression in pDCs was analysed by an expression array. DSR-6434 triggered 20-fold lower levels of IFN-α by pDCs, but higher production of IL-6, IL-8 and TNF, compared to RNA-IC. Furthermore, IFN-α and TNF production were increased with exogenous IFN-α2b priming, whereas IL-8 synthesis by B cells was reduced for both stimuli. Cocultivation of pDCs and B cells increased the RNA-IC-stimulated IFN-α and TNF levels, while only IL-6 production was enhanced in the DSR-6434-stimulated cocultures. When comparing pDCs stimulated with RNA-IC and DSR-6434, twelve genes were differentially expressed (log2 fold change >2, adjusted P-value <.05). In conclusion, RNA-IC, which mimics an endogenous TLR7 stimulator, and the synthetic TLR7 agonist DSR-6434 trigger distinct inflammatory profiles in immune cells. This demonstrates the importance of using relevant stimuli when targeting the TLR7 pathway for therapeutic purposes.
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| 2. |
- Hedlund, Malin, et al.
(författare)
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Type I IFN system activation in newborns exposed to Ro/SSA and La/SSB autoantibodies in utero
- 2020
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Ingår i: RMD Open. - : BMJ. - 2056-5933. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: In utero exposure of the fetus to Ro/La autoantibodies may lead to congenital heart block (CHB). In the mother, these autoantibodies are associated with activation of the type I interferon (IFN)-system. As maternal autoantibodies are transferred to the fetus during pregnancy, we investigated whether the type I IFN-system is activated also in newborns of anti-Ro/La positive mothers, and whether fetal IFN activation is affected by maternal immunomodulatory treatment.METHODS: Blood drawn at birth from anti-Ro/La positive mothers, their newborns and healthy control pairs was separated into plasma and peripheral blood mononuclear cells (PBMC). PBMC were analysed directly or cultured. mRNA expression was analysed by microarrays, cell surface markers by flow cytometry, and IFNα levels by immunoassays.RESULTS: We observed increased expression of IFN-regulated genes and elevated plasma IFNα levels not only in anti-Ro/La positive women, but also in their newborns. CD14+ monocytes of both anti-Ro/La positive mothers and their neonates showed increased expression of Sialic acid-binding Ig-like lectin-1, indicating cellular activation. Notably, the IFN score of neonates born to mothers receiving immunomodulatory treatment was similar to that of controls, despite persistent IFN activation in the mothers. In both maternal and neonatal PBMC, IFNα production was induced when cells were cultured with anti-Ro/La positive plasma.CONCLUSIONS: Ro/La autoantibody-exposed neonates at risk of CHB have signs of an activated immune system with an IFN signature. This study further demonstrates that neonatal cells can produce IFNα when exposed to autoantibody-containing plasma, and that maternal immunomodulatory treatment may diminish the expression of IFN-regulated genes in the fetus.
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| 3. |
- Hjorton, Karin, 1974-
(författare)
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The activation and regulation of plasmacytoid dendritic cells in SLE : and possible therapeutic interventions
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Systemic Lupus Erythematosus (SLE) is an autoimmune disease, characterized by the presence of anti-nuclear antibodies and the formation of nucleic acid containing immune complexes (ICs), which can cause organ damage by deposition in tissues. ICs strongly trigger the plasmacytoid dendritic cells (pDCs) to produce interferon (IFN)-α, which potently activates the immune system. An activated type I IFN system is seen in a majority of SLE patients. Natural killer (NK) cells enhance the IC triggered response of pDCs. Other NK cell alterations are described in SLE. Standard SLE treatment, hydroxychloroquine (HCQ), reduces flare risks, and HCQ concentration measurement can optimize its dosing. However, new treatments are needed.In paper I, we screened for autoantibodies to lectin-like NK cell receptors. In 3.4% of SLE patient sera, autoantibodies to CD94/NKG2A and CD94/NKG2C were found, which interfered with HLA-E mediated regulation of NK cell cytotoxicity, and facilitated elimination of target cells expressing expressing these receptors. Autoantibody levels correlated with SLE disease activity and with a more severe disease phenotype.In paper II, we found that RNA-IC triggered proinflammatory cytokine production in immune cells from healthy blood donors and SLE patients. After RNA-IC stimulation of pDCs, RNA sequencing detected 975 differentially expressed genes, connected to cytokine pathways, cell regulation and apoptosis. An IRAK4i had a broader inhibitory effect on RNA-IC triggered cytokine production and pro-inflammatory pathways than HCQ.In paper III we showed that RNA-IC induced type III IFN production in a subset of pDCs (3%) which also produced type I IFN. Type III IFN production by pDCs was enhanced by NK and B cells, as well as by IFN-λ2, IFN-α2b, interleukin (IL)-3, IL-6 and GM-CSF. Type III IFN production by RNA-IC stimulated immune cells of SLE patients was detected in a minority. IFN-α2b and GM-CSF increased the proportion of responders to RNA-IC from 11 to 33%.In paper IV a LC-HRMS method, was evaluated for HCQ concentration measurement in whole blood (WB), serum and plasma from 26 SLE patients. The levels in WB were approximately 2-fold compared to serum and plasma, and correlated with weekly HCQ-dose. Large inter-individual variations were observed, despite equal doses. The WB matrix showed superior reproducibility in patient samples (CV<5%).These findings add to the knowledge of how cytokine production by pDCs in SLE is regulated, and support a role for NK cells in the pathogenesis of SLE. Moreover WB was the superior matrix for HCQ measurement in SLE patients.
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| 4. |
- Hjorton, Karin, 1974-, et al.
(författare)
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The regulation and pharmacological modulation of immune complex induced type III IFN production by plasmacytoid dendritic cells
- 2020
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Ingår i: Arthritis Research & Therapy. - : Springer Science and Business Media LLC. - 1478-6362. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivePatients with systemic lupus erythematosus (SLE) have an ongoing interferon (IFN) production due to an activation of plasmacytoid dendritic cells (pDCs), which can be triggered to type I IFN synthesis by RNA containing immune complexes (RNA-IC). Considering emerging data suggesting a role of type III IFN in the SLE disease process, we asked if RNA-IC can induce type III IFN production in pDC and how this production can be regulated.MethodsPeripheral blood mononuclear cells (PBMCs) or immune cell subsets were isolated from healthy blood donors or SLE patients and stimulated with IC containing U1 snRNP and SLE-IgG (RNA-IC). Hydroxychloroquine (HCQ) and an interleukin receptor 1-associated kinase 4 inhibitor (IRAK4i) were added to cell cultures. Cytokine mRNA levels were determined with a microarray and protein levels with immunoassays. Single-cell RNA sequencing of pDCs using ddSEQ technology was performed.ResultsType III IFN mRNA and protein was induced in RNA-IC-stimulated pDC-NK and pDC-B cell co-cultures. A subset of activated pDCs (3%) expressed both type III and type I IFN mRNA. IFN-λ2, IFN-α2b, interleukin (IL)-3, IL-6, or granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced IFN-λ1/3 production 2–5-fold. HCQ and an IRAK4i blocked the RNA-IC-triggered IFN-λ1/3 production (p < 0.01). IFN-α2b and GM-CSF increased the proportion of SLE patients producing IFN-λ1/3 in response to RNA-IC from 11 to 33%.ConclusionsType III IFN production is triggered by RNA-IC in pDCs in a TLR-MyD88-dependent manner, enhanced by NK and B cells as well as several pro-inflammatory cytokines. These results support a contributing role for both type I and type III IFNs in SLE, which needs to be considered when targeting the IFN system in this disease.
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| 5. |
- Lundtoft, Christian, et al.
(författare)
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Function of multiple sclerosis-protective HLA class I alleles revealed by genome-wide protein-quantitative trait loci mapping of interferon signalling
- 2020
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 16:10
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Tidskriftsartikel (refereegranskat)abstract
- Interferons (IFNs) are cytokines that are central to the host defence against viruses and other microorganisms. If not properly regulated, IFNs may contribute to the pathogenesis of inflammatory autoimmune, or infectious diseases. To identify genetic polymorphisms regulating the IFN system we performed an unbiased genome-wide protein-quantitative trait loci (pQTL) mapping of cell-type specific type I and type II IFN receptor levels and their responses in immune cells from 303 healthy individuals. Seven genome-wide significant (p < 5.0E-8) pQTLs were identified. Two independent SNPs that tagged the multiple sclerosis (MS)-protective HLA class I alleles A*02/A*68 and B*44, respectively, were associated with increased levels of IFNAR2 in B and T cells, with the most prominent effect in IgD–CD27+ memory B cells. The increased IFNAR2 levels in B cells were replicated in cells from an independent set of healthy individuals and in MS patients. Despite increased IFNAR2 levels, B and T cells carrying the MS-protective alleles displayed a reduced response to type I IFN stimulation. Expression and methylation-QTL analysis demonstrated increased mRNA expression of the pseudogene HLA-J in B cells carrying the MS-protective class I alleles, possibly driven via methylation-dependent transcriptional regulation. Together these data suggest that the MS-protective effects of HLA class I alleles are unrelated to their antigen-presenting function, and propose a previously unappreciated function of type I IFN signalling in B and T cells in MS immune-pathogenesis.Author summaryGenetic association studies have been very successful in identifying disease-associated single nucleotide polymorphisms (SNPs), but it has been challenging to define the molecular mechanisms underlying these associations. As interferons (IFNs) have a central role in the immune system, we hypothesized that some of the SNPs associated to immune-mediated diseases would affect the IFN system. By combining genetic data with characterization of interferon receptor levels and their responses on the protein level in immune cells from 303 genotyped healthy individuals, we show that two SNPs tagging the HLA class I alleles A*02/A*68 and B*44 are associated with a decreased response to type I IFN stimulation in B cells and T cells. Notably, both HLA-A*02 and HLA-B*44 confer protection from developing multiple sclerosis (MS), which is a chronic inflammatory neurologic disease. In addition to suggesting a pathogenic role of enhanced type I interferon signalling in B cells and T cells in MS, our data emphasize the fact that genetic associations in the HLA locus can affect functions not directly associated to antigen presentation, which conceptually may be important for other diseases genetically associated to the HLA locus.
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| 6. |
- Reid, Sarah, et al.
(författare)
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High genetic risk score is associated with early disease onset, damage accrual and decreased survival in systemic lupus erythematosus
- 2020
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ Publishing Group Ltd. - 0003-4967 .- 1468-2060. ; 79:3, s. 363-369
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate associations between a high genetic disease risk and disease severity in patients with systemic lupus erythematosus (SLE).METHODS: Patients with SLE (n=1001, discovery cohort and n=5524, replication cohort) and healthy controls (n=2802 and n=9859) were genotyped using a 200K Immunochip single nucleotide polymorphism array. A genetic risk score (GRS) was assigned to each individual based on 57 SLE risk loci.RESULTS: SLE was more prevalent in the high, compared with the low, GRS-quartile (OR 12.32 (9.53 to 15.71), p=7.9×10-86 and OR 7.48 (6.73 to 8.32), p=2.2×10-304 for the discovery and the replication cohorts, respectively). In the discovery cohort, patients in the high GRS-quartile had a 6-year earlier mean disease onset (HR 1.47 (1.22 to 1.75), p=4.3×10-5), displayed higher prevalence of damage accrual (OR 1.47 (1.06 to 2.04), p=2.0×10-2), renal disorder (OR 2.22 (1.50 to 3.27), p=5.9×10-5), anti-dsDNA (OR 1.83 (1.19 to 2.81), p=6.1×10-3), end-stage renal disease (ESRD) (OR 5.58 (1.50 to 20.79), p=1.0×10-2), proliferative nephritis (OR 2.42 (1.30 to 4.49), p=5.1×10-3), anti-cardiolipin-IgG (OR 1.89 (1.13 to 3.18), p=1.6×10-2), anti-β2-glycoprotein-I-IgG (OR 2.29 (1.29 to 4.06), p=4.8×10-3) and positive lupus anticoagulant test (OR 2.12 (1.16 to 3.89), p=1.5×10-2) compared with patients in the low GRS-quartile. Survival analysis showed earlier onset of the first organ damage (HR 1.51 (1.04 to 2.25), p=3.7×10-2), first cardiovascular event (HR 1.65 (1.03 to 2.64), p=2.6×10-2), nephritis (HR 2.53 (1.72 to 3.71), p=9.6×10-7), ESRD (HR 6.78 (1.78 to 26.86), p=6.5×10-3) and decreased overall survival (HR 1.83 (1.02 to 3.30), p=4.3×10-2) in high to low quartile comparison.CONCLUSIONS: A high GRS is associated with increased risk of organ damage, renal dysfunction and all-cause mortality. Our results indicate that genetic profiling may be useful for predicting outcomes in patients with SLE.
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