Lupus erythematosus. Part I: epidemiology, genetics and immunology

Downregulation of Macrophage-Specific Act-1 Intensifies Periodontitis and Alveolar Bone Loss Possibly via TNF/NF-κB Signaling

Periodontitis is a chronic inflammatory oral disease that affects almost half of the adult population. NF-κB activator 1 (Act1) is mainly expressed in immune cells, including macrophages, and modulates immune cells' function to regulate inflammation in inflammatory diseases. Macrophages play a vital role in the pathophysiology of periodontitis. However, the effect of macrophage-specific Act1 on periodontitis has not been investigated yet. This study aims to unravel the role of macrophage-specific Act1 on the pathophysiology of periodontitis. The expression of Act1 in healthy and periodontitis periodontal tissue was confirmed by immunohistochemistry. Macrophage-specific Act1 expression downregulated (anti-Act1) mice were developed by inserting anti-Act1 antisense oligonucleotides after the CD68 promoter of C57BL/6 mice. Ligature-induced periodontitis (LIP) was induced in anti-Act1 mice and wildtype mice. Micro-CT, histology, and TRAP staining analyzed the periodontal tissue status, alveolar bone loss, and osteoclast numbers. Immunohistochemistry, RT-qPCR, and ELISA analyzed the inflammatory cells infiltration, expression of inflammatory cytokines, and M1/M2 macrophage polarization. mRNA sequencing of in vitro bacterial lipopolysaccharide (LPS)-treated peritoneal macrophages analyzed the differentially expressed genes in anti-Act1 mice during inflammation. Anti-Act1 mice showed aggravated periodontitis and alveolar bone loss compared to wildtype. Periodontitis-affected periodontal tissue (PAPT) of anti-Act1 mice showed a higher degree of macrophage infiltration, and M1 macrophage polarization compared to wildtype. Levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNFα), and macrophage activity-related factors (CCL2, CCL3, and CCL4) were robustly high in PAPT of anti-Act1 mice compared to wildtype. mRNA sequencing and KEGG analysis showed activated TNF/NF-κB signaling in LPS-treated macrophages from anti-Act1 mice. In vitro studies on LPS-treated peritoneal macrophages from anti-act1 mice showed a higher degree of cell migration and expression of inflammatory cytokines, macrophage activity-related factors, M1 macrophage-related factors, and TNF/NF-κB signaling related P-p65 protein. In conclusion, downregulation of macrophage-specific Act1 aggravated periodontitis, alveolar bone loss, macrophage infiltration, inflammation, and M1 macrophage polarization. Furthermore, LPS-treated macrophages from anti-Act1 mice activated TNF/NF-κB signaling. These results indicate the distinct role of macrophage-specific Act1 on the pathophysiology of periodontitis possibly via TNF/NF-κB signaling.

Topics on vitamin D in systemic lupus erythematosus: analysis of evidence and critical literature review

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multiorgan inflammation, linked to the loss of immune tolerance to self-antigens and the production of a diversity of autoantibodies. The phenotype and progression of SLE have been linked to a combination of environmental, genetic, and hormonal factors. One such environmental factor is vitamin D, a vital hormone with well-established effects on mineral metabolism, skeletal health, and effects on cardiovascular system. The purpose of this article is to make the analysis of evidence and literature review of the pleomorphic effects of Vitamin D in SLE. The article is structured in topics of interest based in the authors' opinion and summarizes the evidence of studies and trials of vitamin D in SLE.

Association of polymorphic variants of PTPN22, TNF and VDR systems in children with lupus nephritis: a study in trios of Colombian families

Introducción. El lupus eritematoso sistémico es una enfermedad autoinmune cuya gravedad varía según la raza, género y edad de aparición. Esta disparidad también se observa en los marcadores genéticos asociados con la enfermedad presentes en los genes PTPN22, VDR y TNF. La estratificación genética que presentan las diferentes poblaciones en el mundo puede estar influyendo dicha variabilidad.Objetivo. Analizar la asociación y heredabilidad de variantes genéticas de los genes PTPN22, VDR y TNF con nefritis lúpica pediátrica (NLp) en familias colombianas.Materiales y métodos. Se realizó un estudio basado en familias con 46 tríos (caso/padre y madre). Se genotipificaron las variantes rs2476601 de PTPN22; rs361525 y rs1800629 de TNF; TaqI [rs731236], ApaI [rs7975232], BsmI [rs1544410] y FokI [rs2228570] de VDR mediante qPCR. Se estimó el efecto de la sobretransmisión del alelo de riesgo de padres a hijos y el desequilibrio de ligamiento de los loci VDR y TNF.Resultados. Se observó que el alelo A de rs2476601 en PTPN22 se distribuyó en el 8,69 % [n=16] de los padres mientras que en los casos es de 19,5 % [n=18] al igual que es sobretransmitido de padres a hijos 17 veces más con relación al alelo G (p=0,028). Los polimorfismos de TNF y VDR no se mostraron en desequilibrio de transmisión. Las variantes TaqI, ApaI y BsmI del VDR se mostraron en desequilibrio de ligamiento.Conclusión. Estos hallazgos muestran una asociación del polimorfismo rs2476601 de PTPN22 con NLp debido a su sobretransmisión en el grupo de familias estudiadas.

C/EBP β mRNA expression is upregulated and positively correlated with the expression of TNIP1/TNFAIP3 in peripheral blood mononuclear cells from patients with systemic lupus erythematosus

CCAAT/enhancer-binding protein β (C/EBP β) has important roles in numerous signaling pathways. The expression of the majority of regulators and target gene products of C/EBP β, including tumor necrosis factor α-induced protein 3 (TNFAIP3) and TNFAIP3-interacting protein 1 (TNIP1), are upregulated in patients with systemic lupus erythematosus (SLE). The aim of the present study was to investigate whether C/EBP β expression is associated with SLE pathogenesis and correlates with TNIP1 and TNFAIP3 expression. Quantitative reverse transcription-polymerase chain reaction analysis was used to assess the expression of C/EBP β, TNIP1, and TNFAIP3 mRNA in peripheral blood mononuclear cells (PBMC) from 20 patients with SLE and 20 healthy controls. Spearman's rank test was used to determine the correlation between C/EBP β expression and SLE disease activity, and that between C/EBP β expression and TNIP1/TNFAIP3 expression in PBMCs from patients with SLE. C/EBP β mRNA expression was markedly increased in patients with SLE compared with healthy controls. The expression of C/EBP β was positively correlated with the SLE disease activity index and negatively correlated with the serum level of complement components C3 and C4. In addition, C/EBP β mRNA expression was increased in PBMCs from SLE patients that were positive for antinuclear, anti-Smith and anti-nRNP antibodies, compared with the antibody negative SLE patients. Furthermore, the mRNA expression levels of C/EBP β in patients with SLE was positively correlated with TNIP1 and TNFAIP3 expression. The results of the current study suggest that the increased expression of C/EBP β in PBMCs and the interaction between C/EBP β and TNIP1/TNFAIP3 may be involved in the pathogenesis of SLE.

MicroRNA analysis suggests an additional level of feedback regulation in the NF-κB signaling cascade

It is increasingly clear that the biological functions of a transcription factor cannot be fully understood solely on the basis of protein-coding genes that fall under its control. Many transcription factors regulate expression of miRNAs, which affect the cell by modulating translation and stability of mRNAs. The identities and the roles of NF-κB-regulated miRNAs have been attracting research interest for a long time. We revisited this issue in a system with controlled expression of one of the key regulators of NF-κB, RIPK1. Several regulated miRNAs were identified, including miR-146a, miR-215 and miR-497. The miRNAs were also inducible by IL-1β, but not when NF-κB activity was repressed by mutant IκBα. The presence of a miR-497 site was predicted in the 3′-UTR of IKBKB gene, which encodes IKKβ. Using appropriately engineered reporters, we confirmed that this site can be a target of suppressive action of miR-497. Our findings suggest that NF-κB controls expression of a miRNA, which may reduce production of IKKβ. Considering the role of IKKβ in the canonical pathway of NF-κB activation, our observations may indicate a new mechanism that modulates the magnitude of such activation, as well as the propensity of a cell to engage canonical vs. non-canonical pathways.