Isolevuglandins disrupt PU.1 mediated C1q expression and promote autoimmunity and hypertension in systemic lupus erythematosus
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ABSTRACT: To determine the gene expression of profile of dendritic cells (DCs) from lupus prone mice we sorted CD11c+ cells from 4 7 week old female C57Bl/6 mice and 4 7 week old B6.SLE123 mice. We then performed gene expression profiling analysis using data obtained from RNA-seq from DCs of these 8 animals.
Project description:We describe a mechanism responsible for systemic lupus erythematosus (SLE). In humans with SLE and in 2 SLE murine models, there was marked enrichment of isolevuglandin-adducted proteins (isoLG adducts) in monocytes and dendritic cells. We found that antibodies formed against isoLG adducts in both SLE-prone mice and humans with SLE. In addition, isoLG ligation of the transcription factor PU.1 at a critical DNA binding site markedly reduced transcription of all C1q subunits. Treatment of SLE-prone mice with the specific isoLG scavenger 2-hydroxybenzylamine (2-HOBA) ameliorated parameters of autoimmunity, including plasma cell expansion, circulating IgG levels, and anti-dsDNA antibody titers. 2-HOBA also lowered blood pressure, attenuated renal injury, and reduced inflammatory gene expression uniquely in C1q-expressing dendritic cells. Thus, isoLG adducts play an essential role in the genesis and maintenance of systemic autoimmunity and hypertension in SLE.
Project description:C1q deficiency is a rare immunodeficiency, which is strongly associated with the development of systemic lupus erythematosus (SLE). A mutation in one of the C1q genes can either lead to complete deficiency or to low C1q levels with C1q polypeptide in the form of low-molecular weight (LMW) C1q. Patients with C1q deficiency mainly present with cutaneous and renal involvement. Although less frequent, neuropsychiatric (NP) involvement has also been reported in 20% of the C1q-deficient patients. This involvement appears to be absent in other deficiencies of early components of the complement classical pathway (CP) (C1r/C1s, C2, or C4 deficiencies). We describe a new case with C1q deficiency with a homozygous G34R mutation in C1qC-producing LMW-C1q presenting with a severe SLE flare with NP involvement. The serum of this patient contained very low levels of a LMW variant of C1q polypeptides. Cell lysates contained the three chains of C1q, but no intact C1q was detected, consistent with the hypothesis of the existence of a LMW-C1q. Furthermore, we provide a literature overview of NP-SLE in C1q deficiency and hypothesize about the potential role of C1q in the pathogenesis of NP involvement in these patients. The onset of NP-SLE in C1q-deficient individuals is more severe when compared with complement competent NP-SLE patients. An important number of cases present with seizures and the most frequent findings in neuroimaging are changes in basal ganglia and cerebral vasculitis. A defective CP, because of non-functional C1q, does not protect against NP involvement in SLE. The absence of C1q and, subsequently, some of its biological functions may be associated with more severe NP-SLE.
Project description:Oxidative injury and inflammation have been implicated in the genesis of hypertension but the mechanisms involved are not fully understood. We describe a new pathway in which angiotensin II promotes dendritic cell (DC) activation of T cells and ultimately hypertension. NADPH oxidase-dependent superoxide production is increased 5-fold in DCs isolated from hypertensive mice as compared to sham-treated mice. This is associated with DC accumulation of protein-isoketal adducts and production of IL-6, IL-1β and IL-23. DCs from hypertensive mice but not sham mice promote survival and proliferation of CD8+ T cells in culture. Chemically diverse isoketal scavengers not only prevent activation and immunogenicity of DCs, but also attenuate angiotensin II-induced hypertension. Moreover, adaptive transfer of DCs from hypertensive mice prime development of hypertension in response to a subpressor dose of angiotensin II. Exposure of DCs to tert butyl hypdroperoxide promoted isoketal formation, DC stimulation of CD8+ T cell proliferation and primed hypertension in response to low dose angiotensin II. Serum isoprostanes, precursors to isoketals, were found to be elevated in humans with treated hypertension and were markedly elevated in patients with resistant hypertension. These studies show that angiotensin II-induced hypertension activates DCs, in large part by causing superoxide production and formation of isoketals. They define a new mechanism of hypertension and identify a potential new therapeutic approach for this disease. We used microarrays to detail the expression differences in dendritic cells under hypertensive conditions. Dendritic cells were isolated from mosue spleen and subsequently treated with Angiotensin II with or without co-treatment with 2-hydroxybenzylamine (2-HOBA) for RNA extraction and hybridization on Affymetrix microarrays. We sought to determine the effect of oxidative stress on dendritic cell expression profiles.
Project description:C1q is of interest in systemic lupus erythematosus (SLE) research due to deficiencies in its activity being associated with the disease. Current published protocols for measuring C1q vary greatly in their results and ease of reproducibility. Due to this, average C1q concentrations have been reported between 56 and 276 microg/mL in non-SLE serum. We present an improved method for quantifying C1q concentrations, which employs a sandwich ELISA. This method has improved precision, cost efficiency, up-scaling, reproducibility, and uses significantly lesser volumes of serum sample when compared to RID and other methods for quantifying C1q. We report an average concentration of 113 +/- 40 microg/mL for C1q in non-SLE serum. The assay designed here will be useful in the high-throughput measurement of serum C1q in SLE cases.
Project description:To investigated how SPI1 inhibitor (DB2313) affected the function of DCs , we treated BMDM derived DCs,with DB2313. We then performed gene expression profiling analysis using data obtained from RNA-seq of peritoneal DCs with DB2313
Project description:Oxidative injury and inflammation have been implicated in the genesis of hypertension but the mechanisms involved are not fully understood. We describe a new pathway in which angiotensin II promotes dendritic cell (DC) activation of T cells and ultimately hypertension. NADPH oxidase-dependent superoxide production is increased 5-fold in DCs isolated from hypertensive mice as compared to sham-treated mice. This is associated with DC accumulation of protein-isoketal adducts and production of IL-6, IL-1β and IL-23. DCs from hypertensive mice but not sham mice promote survival and proliferation of CD8+ T cells in culture. Chemically diverse isoketal scavengers not only prevent activation and immunogenicity of DCs, but also attenuate angiotensin II-induced hypertension. Moreover, adaptive transfer of DCs from hypertensive mice prime development of hypertension in response to a subpressor dose of angiotensin II. Exposure of DCs to tert butyl hypdroperoxide promoted isoketal formation, DC stimulation of CD8+ T cell proliferation and primed hypertension in response to low dose angiotensin II. Serum isoprostanes, precursors to isoketals, were found to be elevated in humans with treated hypertension and were markedly elevated in patients with resistant hypertension. These studies show that angiotensin II-induced hypertension activates DCs, in large part by causing superoxide production and formation of isoketals. They define a new mechanism of hypertension and identify a potential new therapeutic approach for this disease. We used microarrays to detail the expression differences in dendritic cells under hypertensive conditions.
Project description:17 organs were harvested from 4 12 week old and 4 84 week old male mice. Proteomics for this set was performed by diaPASEF analysis using an EvoSep 60 speed method.