mTORC2 contributes to murine lupus

ABSTRACTThe development of systemic lupus erythematosus (SLE) is associated with overactivation of the type I interferon (IFN) pathway, lymphopenia, and increased follicular helper T (Tfh) cell differentiation. However, the cellular and molecular mechanisms of action of type I IFN in SLE remains incompletely understood. Here we show that type I IFN activates the mechanistic target of rapamycin complex 2 (mTORC2) in T cells to promote T cell lymphopenia. mTORC2 also promotes Tfh differentiation and disrupts Treg homeostasis. Inactivation of mTORC2 greatly ameliorated the immunopathology in a lupus-prone mouse model, associated with reduced Tfh differentiation, normalization of Treg homeostasis and reduced T cell glucose metabolism. These data indicate that mTORC2 acts downstream of type I IFN and costimulatory receptor ICOS, to promote T cell lymphopenia and Tfh differentiation in murine lupus development, suggesting that inhibition of mTORC2 could limit lupus disease progression.

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Type I interferons affect the metabolic fitness of CD8+ T cells from patients with systemic lupus erythematosus

Nature Communications ◽

10.1038/s41467-021-22312-y ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Norzawani Buang ◽

Lunnathaya Tapeng ◽

Victor Gray ◽

Alessandro Sardini ◽

Chad Whilding ◽

...

Keyword(s):

Systemic Lupus Erythematosus ◽

T Cells ◽

Cell Death ◽

T Cell ◽

Lupus Erythematosus ◽

Type I Interferons ◽

Type I ◽

Type I Ifn ◽

Systemic Lupus ◽

Mitochondrial Abnormalities

AbstractThe majority of patients with systemic lupus erythematosus (SLE) have high expression of type I IFN-stimulated genes. Mitochondrial abnormalities have also been reported, but the contribution of type I IFN exposure to these changes is unknown. Here, we show downregulation of mitochondria-derived genes and mitochondria-associated metabolic pathways in IFN-High patients from transcriptomic analysis of CD4+ and CD8+ T cells. CD8+ T cells from these patients have enlarged mitochondria and lower spare respiratory capacity associated with increased cell death upon rechallenge with TCR stimulation. These mitochondrial abnormalities can be phenocopied by exposing CD8+ T cells from healthy volunteers to type I IFN and TCR stimulation. Mechanistically these ‘SLE-like’ conditions increase CD8+ T cell NAD+ consumption resulting in impaired mitochondrial respiration and reduced cell viability, both of which can be rectified by NAD+ supplementation. Our data suggest that type I IFN exposure contributes to SLE pathogenesis by promoting CD8+ T cell death via metabolic rewiring.

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Molecular mechanisms of vasculopathy and coagulopathy in COVID-19

Biological Chemistry ◽

10.1515/hsz-2021-0245 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Suzan Al-Gburi ◽

Stefan Beissert ◽

Claudia Günther

Keyword(s):

Angiotensin Ii ◽

Disease Control ◽

Lupus Erythematosus ◽

Molecular Mechanisms ◽

Multiple Organ ◽

Type I ◽

Type I Ifn ◽

Systemic Complications ◽

Small Vessels ◽

Specific Regulation

Abstract COVID-19 primarily affects the respiratory system and may lead to severe systemic complications, such as acute respiratory distress syndrome (ARDS), multiple organ failure, cytokine storm, and thromboembolic events. Depending on the immune status of the affected individual early disease control can be reached by a robust type-I-interferon (type-I-IFN) response restricting viral replication. If type-I-IFN upregulation is impaired, patients develop severe COVID-19 that involves profound alveolitis, endothelitis, complement activation, recruitment of immune cells, as well as immunothrombosis. In patients with proper initial disease control there can be a second flare of type-I-IFN release leading to post-COVID manifestation such as chilblain-like lesions that are characterized by thrombosis of small vessels in addition to an inflammatory infiltrate resembling lupus erythematosus (LE). Mechanistically, SARS-CoV-2 invades pneumocytes and endothelial cells by acting on angiotensin-II-converting enzyme 2 (ACE2). It is hypothesized, that viral uptake might downregulate ACE2 bioavailability and enhance angiotensin-II-derived pro-inflammatory and pro-thrombotic state. Since ACE2 is encoded on the X chromosome these conditions might also be influenced by gender-specific regulation. Taken together, SARS-CoV-2 infection affects the vascular compartment leading to variable thrombogenic or inflammatory response depending on the individual immune response status.

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Heterozygous RELA mutations cause early-onset systemic lupus erythematosus by hijacking the NF-κB pathway towards transcriptional activation of type-I Interferon genes

10.1101/2020.04.27.046102 ◽

2020 ◽

Author(s):

Laura Barnabei ◽

Hicham Lamrini ◽

Mathieu Castela ◽

Nadia Jeremiah ◽

Marie-Claude Stolzenberg ◽

...

Keyword(s):

Systemic Lupus Erythematosus ◽

Lupus Erythematosus ◽

Early Onset ◽

Molecular Mechanisms ◽

Type I Interferon ◽

Type I ◽

Type I Ifn ◽

Systemic Lupus ◽

Consensus Sequences ◽

Expression Of Genes

AbstractSystemic Lupus Erythematosus (SLE) is an autoimmune and inflammatory disease characterized by uncontrolled production of autoantibodies and inflammatory cytokines such as the type-I interferons. Due to the lack of precise pathophysiological mechanisms, treatments are based on broad unspecific immunossupression. To identify genetic factors associated with SLE we performed whole exome sequencing and identified two RELA heterozygous activating mutations in 3 early-onset and familial SLE cases. The corresponding RELA/p65 mutant were abundant in the nucleus but poorly activate transcription of genes controlled by NF-κB consensus sequences. The co-expression of the mutant and wild-type RELA/p65 strongly activated the expression of genes controlled by the IFNα-consensus sequences. These molecular mechanisms lead to the overproduction of type-I IFN in the patients’ cells. Our findings highlight a novel mechanism of autoimmunity where these new RELA mutants are transactivating the type-I IFN genes and are thus promoting type-I interferon production and early-onset SLE, thereby paving the way to the identification of new and specific therapeutic targets.SummaryHeterozygous RELA mutations are associated with Systemic Lupus Erythematosus, with increased expression of genes controlled by the IFNα-consensus sequences.

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Relationship Between T-Cell Exosomes and Cellular Subsets in SLE According to Type I IFN-Signaling

Frontiers in Medicine ◽

10.3389/fmed.2020.604098 ◽

2020 ◽

Vol 7 ◽

Author(s):

Patricia López ◽

Javier Rodríguez-Carrio ◽

Luis Caminal-Montero ◽

Ana Suárez

Keyword(s):

Flow Cytometry ◽

T Cells ◽

T Cell ◽

Lupus Erythematosus ◽

Serum Levels ◽

Type I ◽

Type I Ifn ◽

Activation Markers ◽

Cytokines And Chemokines ◽

Cytokine Milieu

Objective: To quantify the levels of circulating exosomes derived from T-cells and monocytes and their possible associations with leukocyte subpopulations and cytokine milieu in Systemic Lupus Erythematosus (SLE).Methods: Total circulating exosomes (CD9+-Ex) and those derived from T-cells (CD3+-Ex) and monocytes (CD14+-Ex) were quantified by flow cytometry in 82 SLE patients and 32 controls. Leukocyte subsets and serum cytokines were analyzed by flow cytometry or by immunoassays. IFN-score was evaluated by real time RT-PCR in whole blood samples from a subgroup of 73 patients and 24 controls.Results: Activation markers (IFNR1 and BLyS) on monocytes, neutrophils and B-cells correlated inversely with circulating exosomes (CD9+-Ex, CD3+-Ex, and CD14+-Ex) in controls but directly with CD3+-Ex in patients (all p < 0.05). Although CD9+-Ex were increased in SLE, no differences were found in CD3+-Ex, supporting that exosome content accounts for this opposite role. Interestingly, CD4+CD28null cells correlated with CD3+-Ex in patients and controls, and displayed similar associations with leukocyte subsets in both groups. Additionally, CD3+-Ex correlated in patients with the expression of CD25 in CD4+CD28null cells. Furthermore, the activated status of this senescent subset was related to IFNα serum levels in controls and to IFN-score in SLE patients. Finally, patients presenting high IFN-score, in addition to elevated CD25+CD28null cells associated with the activation of myeloid cells, displayed higher levels of inflammatory cytokines and chemokines.Conclusion: Our results support a relationship between T-cell exosomes and cellular subsets in SLE according to type I IFN-signaling, which could amplify chronic immune activation and excessive cytokine/chemokine response.

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Faculty Opinions recommendation of A minor population of splenic dendritic cells expressing CD19 mediates IDO-dependent T cell suppression via type I IFN signaling following B7 ligation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1026476.325190 ◽

2005 ◽

Author(s):

Richard Williams

Keyword(s):

Dendritic Cells ◽

T Cell ◽

Type I ◽

Type I Ifn ◽

T Cell Suppression ◽

Minor Population ◽

Cell Suppression ◽

A Minor

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Faculty Opinions recommendation of Netting neutrophils are major inducers of type I IFN production in pediatric systemic lupus erythematosus.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.9075956.9652054 ◽

2011 ◽

Author(s):

Laurence Turka ◽

Scott Lieberman

Keyword(s):

Systemic Lupus Erythematosus ◽

Lupus Erythematosus ◽

Type I ◽

Type I Ifn ◽

Systemic Lupus ◽

Pediatric Systemic Lupus Erythematosus

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OP0005 ELEVATED STAT1 EXPRESSION BUT NOT PHOSPHORYLATION IN LUPUS B CELLS CORRELATES WITH DISEASE ACTIVITY AND INCREASED PLASMABLAST SUSCEPTIBILITY

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.2955 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 4-5

Author(s):

A. Aue ◽

F. Szelinski ◽

S. Weißenberg ◽

A. Wiedemann ◽

T. Rose ◽

...

Keyword(s):

Systemic Lupus Erythematosus ◽

B Cells ◽

Autoimmune Diseases ◽

Disease Activity ◽

B Cell ◽

Lupus Erythematosus ◽

Type I ◽

Type I Ifn ◽

Systemic Lupus ◽

B Cell Subsets

Background:Systemic lupus erythematosus (SLE) is characterized by two pathogenic key signatures, type I interferon (IFN) (1.) and B-cell abnormalities (2.). How these signatures are interrelated is not known. Type I-II IFN trigger activation of Janus kinase (JAK) – signal transducer and activator of transcription (STAT).Objectives:JAK-STAT inhibition is an attractive therapeutic possibility for SLE (3.). We assess STAT1 and STAT3 expression and phosphorylation at baseline and after IFN type I and II stimulation in B-cell subpopulations of SLE patients compared to other autoimmune diseases and healthy controls (HD) and related it to disease activity.Methods:Expression of STAT1, pSTAT1, STAT3 and pSTAT3 in B and T-cells of 21 HD, 10 rheumatoid arthritis (RA), 7 primary Sjögren’s (pSS) and 22 SLE patients was analyzed by flow cytometry. STAT1 and STAT3 expression and phosphorylation in PBMCs of SLE patients and HD after IFNα and IFNγ incubation were further investigated.Results:SLE patients showed substantially higher STAT1 but not pSTAT1 in B and T-cell subsets. Increased STAT1 expression in B cell subsets correlated significantly with SLEDAI and Siglec-1 on monocytes, a type I IFN marker (4.). STAT1 activation in plasmablasts was IFNα dependent while monocytes exhibited dependence on IFNγ.Figure 1.Significantly increased expression of STAT1 by SLE B cells(A) Representative histograms of baseline expression of STAT1, pSTAT1, STAT3 and pSTAT3 in CD19+ B cells of SLE patients (orange), HD (black) and isotype controls (grey). (B) Baseline expression of STAT1 and pSTAT1 or (C) STAT3 and pSTAT3 in CD20+CD27-, CD20+CD27+ and CD20lowCD27high B-lineage cells from SLE (orange) patients compared to those from HD (black). Mann Whitney test; ****p≤0.0001.Figure 2.Correlation of STAT1 expression by SLE B cells correlates with type I IFN signature (Siglec-1, CD169) and clinical activity (SLEDAI).Correlation of STAT1 expression in CD20+CD27- näive (p<0.0001, r=0.8766), CD20+CD27+ memory (p<0.0001, r=0.8556) and CD20lowCD27high (p<0.0001, r=0.9396) B cells from SLE patients with (A) Siglec-1 (CD169) expression on CD14+ cells as parameter of type I IFN signature and (B) lupus disease activity (SLEDAI score). Spearman rank coefficient (r) was calculated to identify correlations between these parameters. *p≤0.05, **p≤0.01. (C) STAT1 expression in B cell subsets of a previously undiagnosed, active SLE patient who was subsequently treated with two dosages of prednisolone and reanalyzed.Conclusion:Enhanced expression of STAT1 by B-cells candidates as key node of two immunopathogenic signatures (type I IFN and B-cells) related to important immunopathogenic pathways and lupus activity. We show that STAT1 is activated upon IFNα exposure in SLE plasmablasts. Thus, Jak inhibitors, targeting JAK-STAT pathways, hold promise to block STAT1 expression and control plasmablast induction in SLE.References:[1]Baechler EC, Batliwalla FM, Karypis G, Gaffney PM, Ortmann WA, Espe KJ, et al. Interferon-inducible gene expression signature in peripheral blood cells of patients with severe lupus. Proc Natl Acad Sci U S A. 2003;100(5):2610-5.[2]Lino AC, Dorner T, Bar-Or A, Fillatreau S. Cytokine-producing B cells: a translational view on their roles in human and mouse autoimmune diseases. Immunol Rev. 2016;269(1):130-44.[3]Dorner T, Lipsky PE. Beyond pan-B-cell-directed therapy - new avenues and insights into the pathogenesis of SLE. Nat Rev Rheumatol. 2016;12(11):645-57.[4]Biesen R, Demir C, Barkhudarova F, Grun JR, Steinbrich-Zollner M, Backhaus M, et al. Sialic acid-binding Ig-like lectin 1 expression in inflammatory and resident monocytes is a potential biomarker for monitoring disease activity and success of therapy in systemic lupus erythematosus. Arthritis Rheum. 2008;58(4):1136-45.Disclosure of Interests:Arman Aue: None declared, Franziska Szelinski: None declared, Sarah Weißenberg: None declared, Annika Wiedemann: None declared, Thomas Rose: None declared, Andreia Lino: None declared, Thomas Dörner Grant/research support from: Janssen, Novartis, Roche, UCB, Consultant of: Abbvie, Celgene, Eli Lilly, Roche, Janssen, EMD, Speakers bureau: Eli Lilly, Roche, Samsung, Janssen

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Listeria exploits IFITM3 to suppress antibacterial activity in phagocytes

Nature Communications ◽

10.1038/s41467-021-24982-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Joel M. J. Tan ◽

Monica E. Garner ◽

James M. Regeimbal ◽

Catherine J. Greene ◽

Jorge D. Rojas Márquez ◽

...

Keyword(s):

Antibacterial Activity ◽

Molecular Mechanisms ◽

Immune Cell ◽

Transmembrane Protein ◽

Foodborne Pathogen ◽

Systemic Infection ◽

Cytokine Signaling ◽

Type I ◽

Type I Ifn ◽

Antiviral Protein

AbstractThe type I interferon (IFN) signaling pathway has important functions in resistance to viral infection, with the downstream induction of interferon stimulated genes (ISG) protecting the host from virus entry, replication and spread. Listeria monocytogenes (Lm), a facultative intracellular foodborne pathogen, can exploit the type I IFN response as part of their pathogenic strategy, but the molecular mechanisms involved remain unclear. Here we show that type I IFN suppresses the antibacterial activity of phagocytes to promote systemic Lm infection. Mechanistically, type I IFN suppresses phagosome maturation and proteolysis of Lm virulence factors ActA and LLO, thereby promoting phagosome escape and cell-to-cell spread; the antiviral protein, IFN-induced transmembrane protein 3 (IFITM3), is required for this type I IFN-mediated alteration. Ifitm3−/− mice are resistant to systemic infection by Lm, displaying decreased bacterial spread in tissues, and increased immune cell recruitment and pro-inflammatory cytokine signaling. Together, our findings show how an antiviral mechanism in phagocytes can be exploited by bacterial pathogens, and implicate IFITM3 as a potential antimicrobial therapeutic target.

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