Interferon-inducible gene 202b controls CD8(+) T cell-mediated suppression in anti-DNA Ig peptide-treated (NZB × NZW) F1 lupus mice

Identification and Contribution of Inflammation-Induced Novel MicroRNA in the Pathogenesis of Systemic Lupus Erythematosus

Recently microRNAs (miRNAs) have been recognized as powerful regulators of many genes and pathways involved in the pathogenesis of inflammatory diseases including Systemic Lupus Erythematosus (SLE). SLE is an autoimmune disease characterized by production of various autoantibodies, inflammatory immune cells, and dysregulation of epigenetic changes. Several candidate miRNAs regulating inflammation and autoimmunity in SLE are described. In this study, we found significant increases in the expression of miR21, miR25, and miR186 in peripheral blood mononuclear cells (PBMCs) of SLE patients compared to healthy controls. However, miR146a was significantly decreased in SLE patients compared to healthy controls and was negatively correlated with plasma estradiol levels and with SLE disease activity scores (SLEDAI). We also found that protein levels of IL-12 and IL-21 were significantly increased in SLE patients as compared to healthy controls. Further, our data shows that protein levels of IL-12 were positively correlated with miR21 expression and protein levels of IL-21 positively correlated with miR25 and miR186 expression in SLE patients. In addition, we found that levels of miR21, miR25, and miR186 positively correlated with SLEDAI and miR146a was negatively correlated in SLE patients. Thus, our data shows a dynamic interplay between disease pathogenesis and miRNA expression. This study has translational potential and may identify novel therapeutic targets in patients with SLE.

Spontaneous CD4+ T Cell Activation and Differentiation in Lupus-Prone B6.Nba2 Mice Is IFNAR-Independent

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by dysregulated T and B lymphocytes. Type I interferons (IFN-I) have been shown to play important pathogenic roles in both SLE patients and mouse models of lupus. Recent studies have shown that B cell intrinsic responses to IFN-I are enough to drive B cell differentiation into autoantibody-secreting memory B cells and plasma cells, although lower levels of residual auto-reactive cells remain present. We speculated that IFN-I stimulation of T cells would similarly drive specific T-cell associated lupus phenotypes including the upregulation of T follicular helper cells and Th17, thereby affecting autoantibody production and the development of glomerulonephritis. Using the B6.Nba2 mouse model of lupus, we evaluated disease parameters in T cell specific IFN-I receptor (IFNAR)-deficient mice (cKO). Surprisingly, all measured CD4+ T cell abnormalities and associated intra-splenic cytokine levels (IFNγ, IL-6, IL-10, IL-17, IL-21) were unchanged and thus independent of IFN-I. In contrast B6.Nba2 cKO mice displayed reduced levels of effector CD8+ T cells and increased levels of Foxp3+ CD8+ regulatory T cells, suggesting that IFN-I induced signaling specifically affecting CD8+ T cells. These data suggest a role for both pathogenic and immunosuppressive CD8+ T cells in Nba2-driven autoimmunity, providing a model to further evaluate the role of these cell subsets during lupus-like disease development in vivo.

Cellular and Molecular Phenotypes of pConsensus Peptide (pCons) Induced CD8+ and CD4+ Regulatory T Cells in Lupus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with widespread inflammation, immune dysregulation, and is associated with the generation of destructive anti-DNA autoantibodies. We have shown previously the immune modulatory properties of pCons peptide in the induction of both CD4⁺ and CD8⁺ regulatory T cells which can in turn suppress development of the autoimmune disease in (NZB/NZW) F1 (BWF1) mice, an established model of lupus. In the present study, we add novel protein information and further demonstrate the molecular and cellular phenotypes of pCons-induced CD4⁺ and CD8⁺ T_reg subsets. Flow cytometry analyses revealed that pCons induced CD8⁺ T_reg cells with the following cell surface molecules: CD25^highCD28^{high and low} subsets (shown earlier), CD62L^high, CD122^low, PD1^low, CTLA4^low, CCR7^low and 41BB^high. Quantitative real-time PCR (qRT-PCR) gene expression analyses revealed that pCons-induced CD8⁺ T_reg cells downregulated the following several genes: Regulator of G protein signaling (RGS2), RGS16, RGS17, BAX, GPT2, PDE3b, GADD45β and programmed cell death 1 (PD1). Further, we confirmed the down regulation of these genes by Western blot analyses at the protein level. To our translational significance, we showed herein that pCons significantly increased the percentage of CD8⁺FoxP3⁺ T cells and further increased the mean fluorescence intensity (MFI) of FoxP3 when healthy peripheral blood mononuclear cells (PBMCs) are treated with pCons (10 μg/ml, for 24-48 hours). In addition, we found that pCons reduced apoptosis in CD4⁺ and CD8⁺ T cells and B220⁺ B cells of BWF1 lupus mice. These data suggest that pCons stimulates cellular, immunological, and molecular changes in regulatory T cells which in turn protect against SLE autoimmunity.

Interferon Genes Are Influenced by 17β-Estradiol in SLE

Recent evidence suggests the existence of a nexus between inflammatory pathways and the female sex hormone 17β-estradiol, resulting in increased interferon-stimulated genes (ISGs), autoantibodies, and dysregulation of immune cells in SLE. However, the molecular mechanisms and the effect of estradiol on candidate target genes and their pathways remains poorly understood. Our previous work suggests that female SLE patients have increased estradiol levels compared to healthy controls. In the present study, we explored the effects of 17β-estradiol treatment on expression of IFN (interferons)-stimulated genes and pro-inflammatory cytokines/chemokines. We found significantly increased (5-10-fold) expression of IFN-regulated genes in healthy females. Furthermore, we found significantly increased plasma levels of IL-6, IL-12, IL-17, IL-18, stem cell factor (SCF), and IL-21/IL-23 in SLE patients compared to healthy controls, and those levels positively correlated with the plasma levels of 17β-estradiol. In addition, levels of IL-21 positively correlated with the SLE disease activity index (SLEDAI) score of SLE patients. In vitro treatment of PBMCs from either SLE patients or healthy controls with 17β-estradiol at physiological concentration (~50 pg/ml) also significantly increased secretion of many pro-inflammatory cytokines and chemokines (IL-6, IL-12, IL-17, IL-8, IFN-γ; MIP1α, and MIP1β) in both groups. Further our data revealed that 17β-estradiol significantly increased the percentage of CD3⁺CD69⁺ and CD3⁺IFNγ⁺ T cells; whereas, simultaneous addition of 17β-estradiol and an ERα inhibitor prevented this effect. Collectively, our findings indicate that 17β-estradiol participates in the induction of pro-inflammatory cytokines and chemokines and further influences interferon genes and pathways.

CD8+ T regulatory cells in lupus

T regulatory cells (Tregs) have a key role in the maintenance of immune homeostasis and the regulation of immune tolerance by preventing the inflammation and suppressing the autoimmune responses. Numerical and functional deficits of these cells have been reported in systemic lupus erythematosus (SLE) patients and mouse models of SLE, where their imbalance and dysregulated activities have been reported to significantly influence the disease pathogenesis, progression and outcomes. Most studies in SLE have focused on CD4+ Tregs and it has become clear that a critical role in the control of immune tolerance after the breakdown of self-tolerance is provided by CD8+ Tregs. Here we review the role, cellular and molecular phenotypes, and mechanisms of action of CD8+ Tregs in SLE, including ways to induce these cells for immunotherapeutic modulation in SLE.

Effects of Peptide-Induced Immune Tolerance on Murine Lupus

The regulation of autoimmunity and the molecular mechanisms by which different immune cells, including T cells, polymorphonuclear leukocytes (PMN-granulocytes), and B cells suppress autoimmune diseases is complex. We have shown previously that BWF1 lupus mice are protected from autoimmunity after i.v. injection or oral administration of tolerogenic doses of pCons, an artificial synthetic peptide based on sequences containing MHC class I and MHC class II determinants in the VH region of a J558-encoded BWF1 anti-DNA Ab. Several T cell subsets can transfer this tolerance. In this study, we determined the potential roles of granulocytes, B cells and regulatory T cells altered by pCons treatment in the BWF1 (NZB/NZW) mouse model of lupus. Immunophenotyping studies indicated that pCons treatment of BWF1 mice significantly increased CD4⁺FoxP3⁺ T cells, reduced the percent of B cells expressing CD19⁺CD5⁺ but increased the percent of CD19⁺CD1d⁺ regulatory B cells and increased the ability of the whole B cell population to suppress IgG anti-DNA production in vitro. pCons treatment significantly decreased the expression of CTLA-4 (cytotoxic T-lymphocyte-associated protein-4) in CD8⁺ T cells. In addition, peptide administration modified granulocytes so they became suppressive. We co-cultured sorted naïve B cells from mice making anti-DNA Ab (supported by addition of sorted naive CD4⁺ and CD8⁺ T cells from young auto-antibody-negative BWF1 mice) with sorted B cells or granulocytes from tolerized mice. Both tolerized granulocytes and tolerized B cells significantly suppressed the production of anti-DNA in vitro. In granulocytes from tolerized mice compared to saline-treated littermate controls, real-time PCR analysis indicated that expression of interferon-induced TNFAIP2 increased more than 2-fold while Ptdss2 and GATA1 mRNA were up-regulated more than 10-fold. In contrast, expression of these genes was significantly down-regulated in tolerized B cells. Further, another IFN-induced protein, Bcl2, was reduced in tolerized B cells as determined by Western blot analyses. In contrast, expression of FoxP3 was significantly increased in tolerized B cells. Together, these data suggest that B cells and granulocytes are altered toward suppressive functions by in vivo tolerization of BWF1 mice with pCons and it is possible these cell types participate in the clinical benefits seen in vivo.

Anti-CD2 Antibody-Coated Nanoparticles Containing IL-2 Induce NK Cells That Protect Lupus Mice via a TGF-β-Dependent Mechanism

We recently reported that the treatment with nanoparticles (NPs) loaded with tolerogenic cytokines suppressed the manifestations of lupus-like disease induced by the transfer of donor CD4+ T cells from DBA/2 mice into (C57BL/6 × DBA/2)F1 (BDF1) mice. Although the protective effects were ascribed to the induction of adaptive CD4+ and CD8+ T regulatory cells, the results suggested that another population of immune cells could be involved. Here we report that NK cells critically contribute to the protection from lupus-like disease conferred by NPs to BDF1 mice, and that this effect is TGF-β-dependent.

Mucocutaneous inflammation in the Ikaros Family Zinc Finger 1-keratin 5-specific transgenic mice

BACKGROUND

Our genomewide association study documented an association between cold medicine-related Stevens-Johnson syndrome/toxic epidermal necrolysis (CM-SJS/TEN) and Ikaros Family Zinc Finger 1 (IKZF1). Few studies examined biological and pathological functions of IKZF1 in mucosal immunity. We hypothesized that IKZF1 contributes to the mucocutaneous inflammation.

METHODS

Human skin and conjunctival tissues were obtained for immunohistological studies. Primary human conjunctival epithelial cells (PHCjECs) and adult human epidermal keratinocytes (HEKa) also used for gene expression analysis. We also generated K5-Ikzf1-EGFP transgenic mice (Ikzf1 Tg) by introducing the Ik1 isoform into cells expressing keratin 5, which is expressed in epithelial tissues such as the epidermis and conjunctiva, and then examined them histologically and investigated gene expression of the epidermis. Moreover, Ikzf1 Tg were induced allergic contact dermatitis.

RESULTS

We found that human epidermis and conjunctival epithelium expressed IKZF1, and in PHCjECs and HEKa, the expression of IKZF1 mRNA was upregulated by stimulation with polyI:C, a TLR3 ligand. In Ikzf1 Tg, we observed dermatitis and mucosal inflammation including the ocular surface. In contact dermatitis model, inflammatory infiltrates in the skin of Ikzf1 Tg were significantly increased compared with wild type. Microarray analysis showed that Lcn2, Adh7, Epgn, Ifi202b, Cdo1, Gpr37, Duoxa1, Tnfrsf4, and Enpp5 genes were significantly upregulated in the epidermis of Ikzf1 Tg compared with wild type.

CONCLUSION

Our findings support the hypothesis that Ikaros might participate in mucocutaneous inflammation.

Decreased expression levels of Ifi genes is associated to the increased resistance to spontaneous arthritis disease in mice deficiency of IL-1RA

Background

The mouse strain BALB/c deficient in IL-1 receptor antagonist protein (Il-1ra) develops spontaneous arthritis disease (SAD) while the strain DBA/1 IL1rn^-/- with the same deficiency does not. Previously, we mapped a QTL on chromosome 1 for SAD and then developed a congenic mouse strain BALB.D1-1^-/- that contains the QTL genomic fragment associated with resistance from DBA/1^-/- on a BALB/c^-/- background. The congenic strain was relatively resistant to spontaneous arthritis and had delayed onset and reduced severity of disease. We obtained whole genome expression profiles from the spleen of the congenic strain BALB.D1-1^-/- and four other strains, the wild type BALB/c, DBA/1 and the deficient DBA/1 IL1rn^-/- and the BALB/c IL1rn^-/-. We then compared the similarities and differences between the congenic strain and the four parental strains. Here we report the selected potential causal genes based on differential expression levels as well as function of genes.

Results

There is a considerable number of genes that are differentially expressed between the congenic strain and the three parental strains, BALB/c, DBA/1, and DBA/1^-/-. However there only a few differentially expressed genes were identified by comparing the congenic strain and the BALB/c^-/-strain. These differentially expressed genes are mainly from T-cell receptor beta chain (Tcrb) and interferon-activatable protein (Ifi) genes. These genes are also differentially expressed between congenic strain and BALB/c strains. However, their expression levels in the congenic strain are similar to that in DBA/1 and DBA/1^-/-. The expression level of Tcrb-j gene is positively associated with two genes of Ifi gene 200 cluster.

Conclusions

Decreased expression levels of Ifi genes is associated to the increased resistance to spontaneous arthritis disease and with down regulation of expressions of Tcrb genes in the mouse congenic strain. Ifi genes may play an important role in the susceptibility to SAD in mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-016-0163-y) contains supplementary material, which is available to authorized users.

Advances in siRNA delivery to T-cells: potential clinical applications for inflammatory disease, cancer and infection

The specificity of RNAi and its ability to silence ‘undruggable’ targets has made inhibition of gene expression in T-cells with siRNAs an attractive potential therapeutic strategy for the treatment of inflammatory disease, cancer and infection. However, delivery of siRNAs into primary T-cells represents a major hurdle to their use as potential therapeutic agents. Recent advances in siRNA delivery through the use of electroporation/nucleofection, viral vectors, peptides/proteins, nanoparticles, aptamers and other agents have now enabled efficient gene silencing in primary T-cells both in vitro and in vivo. Overcoming such barriers in siRNA delivery offers exciting new prospects for directly targeting T-cells systemically with siRNAs, or adoptively transferring T-cells back into patients following ex vivo manipulation with siRNAs. In the present review, we outline the challenges in delivering siRNAs into primary T-cells and discuss the mechanism and therapeutic opportunities of each delivery method. We emphasize studies that have exploited RNAi-mediated gene silencing in T-cells for the treatment of inflammatory disease, cancer and infection using mouse models. We also discuss the potential therapeutic benefits of manipulating T-cells using siRNAs for the treatment of human diseases.

Genes, tolerance and systemic autoimmunity

The characterization of functional CD8(+) inhibitory or regulatory T cells and their gene regulation remains a critical challenge in the field of tolerance and autoimmunity. Investigating the genes induced in regulatory cells and the regulatory networks and pathways that underlie mechanisms of immune resistance and prevent apoptosis in the CD8(+) T cell compartment are crucial to understanding tolerance mechanisms in systemic autoimmunity. Little is currently known about the genetic control that governs the ability of CD8(+) Ti or regulatory cells to suppress anti-DNA Ab production in B cells. Silencing genes with siRNA or shRNA and overexpression of genes with lentiviral cDNA transduction are established approaches to identifying and understanding the function of candidate genes in tolerance and immunity. Elucidation of interactions between genes and proteins, and their synergistic effects in establishing cell-cell cross talk, including receptor modulation/antagonism, are essential for delineating the roles of these cells. In this review, we will examine recent reports which describe the modulation of cells from lupus prone mice or lupus patients to confer anti-inflammatory and protective gene expression and novel associated phenotypes. We will highlight recent findings on the role of selected genes induced by peptide tolerance in CD8(+) Ti.