Upregulated IL-1 Receptor-associated Kinase 1 (IRAK1) in Systemic Lupus Erythematosus: IRAK1 Inhibition Represses Th17 Differentiation with Therapeutic Potential

<p>Systemic lupus erythematosus (SLE) is a typical autoimmune disease. Genome-wide analyses have revealed that interleukin-1 receptor-associated kinase 1 (IRAK1) is associated with susceptibility to SLE. Our previous study investigated the role of IRAK1 in nuclear factor-κB (NF-κB)-related pathways in a mouse model of lupus. In this study, we aimed to further explore the etiological role of IRAK1. The gene expression and phosphorylation of IRAK1 in CD4⁺ T cells from lupus patients and healthy controls were examined by quantitative reverse transcription-polymerase chain reaction and western blotting, respectively. The percentage of circulating Th17 cells and plasma IL-17A levels were evaluated by flow cytometry and enzyme-linked immunosorbent assay, respectively. The influence of IRAK1 suppression on Th17 development was assessed using an IRAK1 inhibitor and small interfering RNA. We found that IRAK1 transcript levels in CD4⁺ T cells were significantly upregulated in SLE patients in comparison to controls and were positively correlated with disease activity. <i>In vitro</i> experiments showed that lupus CD4⁺ T cells had more pronounced IRAK1 phosphorylation at threonine-209 upon IL-1β stimulation than did control cells. Moreover, IRAK1 expression was positively associated with Th17/IL-17A in patients. When naïve CD4⁺ T cells were polarized toward the Th17 subset, IRAK1 inhibition significantly repressed IL-17A production and the gene expression of Th17 markers, namely, retinoic acid receptor-related orphan receptor c, IL-23 receptor and IL-17A. In summary, IRAK1 is overexpressed and hyperactivated in CD4⁺ T cells from SLE patients. IRAK1 inhibition attenuates Th17 differentiation in the context of human SLE, suggesting a therapeutic opportunity.</p

Additional file 3: of Antennal transcriptome analysis of the chemosensory gene families in Carposina sasakii (Lepidoptera: Carposinidae)

Primers designed for fluorescence quantitative real-time PCR. (XLSX 12 kb

Additional file 2: of Antennal transcriptome analysis of the chemosensory gene families in Carposina sasakii (Lepidoptera: Carposinidae)

Amino acid sequences used in phylogenetic trees. (DOCX 196 kb

Additional file 6: of Antennal transcriptome analysis of the chemosensory gene families in Carposina sasakii (Lepidoptera: Carposinidae)

Expression levels of candidate olfactory receptors measured in the RNA-Seq analysis. (XLSX 58 kb

Phenotypic performance of leaf width in five parental lines and four recombinant inbred lines (RILs) across three environments.

<p>Phenotypic performance of leaf width in five parental lines and four recombinant inbred lines (RILs) across three environments.</p

Meta-QTLs (mQTLs) for leaf-width traits in the four recombinant inbred line (RIL) populations across the three environments.

<p>Meta-QTLs (mQTLs) for leaf-width traits in the four recombinant inbred line (RIL) populations across the three environments.</p

Correlation coefficients for the leaf widths at each position above the uppermost ear in the four RIL populations.

<p>FirLW, width of the first leaf above the uppermost ear; SecLW, width of the second leaf above the uppermost ear; ThiLW, width of the third leaf above the uppermost ear; ForLW, width of the fourth leaf above the uppermost ear. The correlation coefficients above the diagonal line in each quadrant of the table are for the Yu82 × Shen137 and Yu537 × Shen137 recombinant inbred lines, and the correlation coefficients below the diagonal line are for the Yu82 × Yu87-1 and Yu82 × Shen137 recombinant inbred lines.</p><p>*Significant at P = 0.05;</p><p>**significant at P = 0.01.</p><p>Correlation coefficients for the leaf widths at each position above the uppermost ear in the four RIL populations.</p

Distribution of single nucleotide polymorphism (SNP) markers in the integrated molecular genetic linkage map.

<p>Distribution of single nucleotide polymorphism (SNP) markers in the integrated molecular genetic linkage map.</p

Hepatitis B Virus Induces IL-23 Production in Antigen Presenting Cells and Causes Liver Damage via the IL-23/IL-17 Axis

<div><p>IL-23 regulates myriad processes in the innate and adaptive immune systems, and is a critical mediator of the proinflammatory effects exerted by Th17 cells in many diseases. In this study, we investigated whether and how hepatitis B virus (HBV) causes liver damage directly through the IL-23 signaling pathway. In biopsied liver tissues from HBV-infected patients, expression of both IL-23 and IL-23R was remarkably elevated. <i>In vivo</i> observations also indicated that the main sources of IL-23 were myeloid dendritic cells (mDCs) and macrophages. Analysis of <i>in vitro</i> differentiated immature DCs and macrophages isolated from healthy donors revealed that the HBV surface antigen (HBsAg) efficiently induces IL-23 secretion in a mannose receptor (MR)-dependent manner. Culture with an endosomal acidification inhibitor and the dynamin inhibitor showed that, upon binding to the MR, the HBsAg is taken up by mDCs and macrophages through an endocytosis mechanism. In contrast, although the HBV core antigen (HBcAg) can also stimulate IL-23 secretion from mDCs, the process was MR- and endocytosis-independent. In addition, IL-23 was shown to be indispensible for HBsAg-stimulated differentiation of naïve CD4⁺ T cells into Th17 cells, which were determined to be the primary source of IL-17 in HBV-infected livers. The cognate receptor, IL-17R, was found to exist on the hepatic stellate cells and mDCs, both of which might represent the potential target cells of IL-17 in hepatitis B disease. These data provide novel insights into a yet unrecognized mechanism of HBV-induced hepatitis, by which increases in IL-23 expression, through an MR/endocytosis-dependent or -independent manner, produce liver damage through the IL-23/IL-17 axis.</p></div

HBsAg induces DCs and macrophages to produce IL-23 in a MR-dependent manner.

<p>(<b>A</b>) Monocytes were isolated from PBMCs of healthy blood donors and mDCs were induced by culturing in the presence of GM-CSF and recombinant human IL-4 for five days. Then, the mDCs were stimulated by various doses of HBsAg or HBcAg. ELISA was used to detect the concentrations of IL-23 and IL-12 in the supernatants. (<b>B</b>) mDCs were stimulated by 50 µL serum from healthy controls (HC) or 50 µL serum from ACLF patients (HBsAg concentration: 79876.4 IU/mL, equivalent to 8 µg/mL) in a 200 µL culture system. For the blocking group, the ACLF serum had been pretreated with HBsAg antibody at a final concentration of 50 µg/mL for 30 min. The concentrations of IL-23 in the supernatants were detected by ELISA. The data represent one of three independent experiments with similar results. Error bars indicate SD. **<i>P</i><0.01 vs. all other groups. (<b>C</b>) mDCs preincubated with mannan (100 µg/mL) or various doses of neutralizing anti-MR antibody for 30 min were stimulated by HBsAg or HBcAg (2 µg/mL, equal to that of HBsAg). Controls were preincubated with medium alone. ELISA was used to detect the concentration of secreted IL-23 in the supernatants. The data represent one of three independent experiments with similar results. Error bars indicate SD. **<i>P</i><0.01; ***<i>P</i><0.001 vs. the HBsAg group. (<b>D</b>) Monocytes were isolated from PBMCs of healthy blood donors and mDCs were induced by culturing for five days in the presence of GM-CSF (50 ng/mL) and recombinant human IL-4 (5 ng/mL). Then, mDCs were stimulated by HBsAg (2 µg/mL) alone or with recombinant human IL-10 (10 ng/mL) <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003410#ppat.1003410-Li2" target="_blank">[27]</a> or with TGF-β (2 ng/mL) <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003410#ppat.1003410-Volpe1" target="_blank">[55]</a>, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003410#ppat.1003410-Yang1" target="_blank">[56]</a> for 48 hours. The supernatant was collected and IL-23 level was detected by ELISA. The data represent one of three independent experiments with similar results. Error bars indicate SD. **<i>P</i><0.01.</p