C-X-C Motif Chemokine Ligand 9 and Its CXCR3 Receptor Are the Salt and Pepper for T Cells Trafficking in a Mouse Model of Gaucher Disease

Gaucher disease is a lysosomal storage disease, which happens due to mutations in GBA1/Gba1 that encodes the enzyme termed as lysosomal acid β-glucosidase. The major function of this enzyme is to catalyze glucosylceramide (GC) into glucose and ceramide. The deficiency of this enzyme and resultant abnormal accumulation of GC cause altered function of several of the innate and adaptive immune cells. For example, augmented infiltration of T cells contributes to the increased production of pro-inflammatory cytokines, (e.g., IFNγ, TNFα, IL6, IL12p40, IL12p70, IL23, and IL17A/F). This leads to tissue damage in a genetic mouse model (Gba1^9V/-) of Gaucher disease. The cellular mechanism(s) by which increased tissue infiltration of T cells occurs in this disease is not fully understood. Here, we delineate role of the CXCR3 receptor and its exogenous C-X-C motif chemokine ligand 9 (CXCL9) in induction of increased tissue recruitment of CD4⁺ T and CD8⁺ T cells in Gaucher disease. Intracellular FACS staining of macrophages (Mϕs) and dendritic cells (DCs) from Gba1^9V/- mice showed elevated production of CXCL9. Purified CD4⁺ T cells and the CD8⁺ T cells from Gba1^9V/- mice showed increased expression of CXCR3. Ex vivo and in vivo chemotaxis experiments showed CXCL9 involvement in the recruitment of Gba1^9V/- T cells. Furthermore, antibody blockade of the CXCL9 receptor (CXCR3) on T cells caused marked reduction in CXCL9- mediated chemotaxis of T cells in Gba1^9V/- mice. These data implicate abnormalities of the CXCL9-CXCR3 axis leading to enhanced tissue recruitment of T cells in Gaucher disease. Such results provide a rationale for blockade of the CXCL9/CXCR3 axis as potential new therapeutic targets for the treatment of inflammation in Gaucher disease.

T Cell Dysregulation in Non-silicotic Silica Exposed Workers: A Step Toward Immune Tolerance Breakdown

Background: Chronic silica exposure can lead to silicosis, complicated or not by autoimmune diseases (AID). The pathophysiology of silica-induced AID remains not fully understood, especially immune mechanisms that may develop in patients without yet established silicosis. We conducted a prospective clinical study to analyze the impact of crystalline silica (CS) on T cell phenotype and regulatory T cells (Tregs) frequency, as well as on auto-antibodies development in non-silicotic workers exposed to CS.

Methods: Workers with moderate to high exposure level to CS and aged between 30 and 60 years-old were considered for inclusion. Peripheral blood mononuclear cells were analyzed by flow cytometry. Auto-antibodies were screened in serum by immunofluorescence. Blood from 42 and 45 healthy subjects (HC) was used as control for T cell phenotype and serum analyses, respectively.

Results: Among the 63 included workers exposed to CS, 55 had full data available and were analyzed. Ten were exposed to CS for <5 years, 18 for 5–10 years and 27 for more than 10 years. The frequency of Tregs (CD4⁺CD25⁺CD127⁻FoxP3⁺) was significantly lower in CS exposed workers as compared to HC. We found an increased expression of the activation marker HLA-DR on T cells (CD3⁺, CD4⁺, and CD8⁺) of CS exposed workers as compared to HC. Tregs to activated T cells ratio was also lower in exposed subjects. In the latter, HLA-DR expression level and Tregs frequency were significantly associated with CS exposure duration. Serum autoantibody detection was significantly higher in CS exposed workers as compared to HC. Especially, among workers exposed more than 10 years, antinuclear antibodies and ANCA were detected in 44 and 22% among them, as compared to 5 and 2.5% in HC, respectively.

Conclusion: This work shows that CS exposure is associated with a decrease of Tregs frequency, an increase of T cell activation status, and a tolerance breakdown against auto-antigens. These results show that alterations of the T cell compartment can be detected early over the course of CS exposure, preceding silicosis development or AID onset.

CD4+CD25+LAG3+ T Cells With a Feature of Th17 Cells Associated With Systemic Lupus Erythematosus Disease Activity

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple immune cell subsets. We analyzed immune cell subsets in human peripheral blood mononuclear cells (PBMC) in order to identify the cells that are significantly associated with SLE disease activity and treatment. The frequencies of various subsets of CD4⁺ T cells, B cells, monocytes and NK cells in PBMC were assessed in 30 healthy controls (HC), 30 rheumatoid arthritis (RA) patients and 26 SLE patients using flow cytometry. The correlations between subset frequencies in SLE and clinical traits including Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) were examined. Changes in subset frequencies after the treatment in SLE patients were investigated. We focused on CD25⁺LAG3⁺ T cells and investigated their characteristics, including cytokine secretion, mRNA expression and suppression capacity. We assessed correlations between CD25⁺LAG3⁺ T cells and SLEDAI by Spearman's rank correlation coefficient. CD25⁺LAG3⁺ T cells were significantly increased in SLE whereas there were few in RA and HC groups. CD25⁺LAG3⁺ T cell frequencies were significantly correlated with SLEDAI and were increased in patients with a high SLEDAI score (> 10). CD25⁺LAG3⁺ T cells produced both IL-17 and FOXP3, expressed mRNA of both FOXP3 and RORC and lacked suppressive capacity. CD25⁺LAG3⁺ T cells were associated with disease activity of SLE. CD25⁺LAG3⁺ T cells had features of both CD25⁺FOXP3⁺ regulatory T cells (CD25⁺ Treg) and Th17. CD25⁺LAG3⁺ T cells could be associated with the inflammatory pathophysiology of SLE.

CXCL12 and CXCR4 polymorphisms and expressions in peripheral blood from patients of hepatocellular carcinoma

AIM

To determine if CXCL12 (rs1801157) and CXCR4 (rs2228014) polymorphisms are associated with hepatocellular carcinoma (HCC) susceptibility, and detect their expressions in peripheral blood.

METHODS

206 HCC patients, 252 chronic hepatitis B patients, 221 liver cirrhosis patients and 275 healthy volunteers were recruited. Genes CXCL12 and CXCR4 were amplified and genotyped. Their expression in peripheral blood were detected.

RESULTS

CXCL12 rs1801157 and CXCR4 rs2228014 polymorphisms were associated with increased susceptibility of HCC, and genotypes GA/AA and CT/TT may be risk factors of HCC (all p < 0.05). Expressions of CXCL12 and CXCR4 in peripheral blood from HCC patients increased significantly (p < 0.05).

CONCLUSION

CXCL12 and CXCR4 polymorphisms may be risk factors for HCC, and they may be potential HCC markers.

Association of rs1801157 single nucleotide polymorphism of CXCL12 gene in breast cancer in Pakistan and in-silico expression analysis of CXCL12-CXCR4 associated biological regulatory network

Background

C-X-C chemokine ligand 12 (CXCL12) has important implications in breast cancer (BC) pathogenesis. It is selectively expressed on B and T lymphocytes and is involved in hematopoiesis, thymocyte trafficking, stem cell motility, neovascularization, and tumorigenesis. The single nucleotide polymorphism (SNP) rs1801157 of CXCL12 gene has been found to be associated with higher risk of BC.

Methods

Our study focuses on the genotypic and allelic distribution of SNP (rs1801157; G/A) in Pakistani population as well as its association with the clinico-pathological features. The association between rs1801157 genotypes (G/A) and BC risks was assessed by a multivariate logistic regression (MLR) analysis. Genotyping was performed in both healthy individuals and patients of BC using PCR-restriction fragment length polymorphism (PCR-RFLP) method. Furthermore, in-silico approaches were adapted to investigate the association of CXCL12 and its receptor CXCR4 with genes/proteins involved in BC signalling.

Results

Significant differences in allelic and genotypic distribution between BC patients and healthy individuals of genotype (G/G) and (A/G) (p < 0.05) were observed. The frequency of the allele G in the BC group (77%) was significantly higher as compared to control group (61%) (p = 0.01). The association of genotype GG with clinico-pathological features including age, stages of cancer and organ (lung, liver, bones and brain) metastasis (p > 0.05) was assessed. In a MLR analysis, a number of variables including age, weight of an individual, affected lymph nodes, hormonal status (estrogen and progesterone receptor), alcohol consumption and family history associated with the GG genotype (GG:AA, odds ratio (OR) = 1.30, 95% CI [1.06–1.60]) were found to be independent risk factors for BC. Our in-vitro results suggest that genotype GG is possibly increasing the risk of BC in Pakistani cohorts. in-silico analysis finds that CXCL12–CXCR4 is associated with an increased expression of PDZK1, PI3k and Akt which lead the breast tumor towards metastasis.

Conclusion

Multiple targets such as CXCL12, CXCR4, PDZK1, PI3k and Akt can be inhibited in combined strategies to treat BC metastasis.

Relationship between rs1801157 polymorphism in stromal cell-derived factor gene and systemic lupus erythematosus risk

Objective

Present meta-analysis was performed to investigate the role of stromal cell-derived factor (SDF-1) gene rs1801157 polymorphism in systemic lupus erythematosus (SLE).

Results

Five publications with 1,087 cases and 1,181 controls were incorporated in this meta-analysis. Overall, a marginal association between SDF-1 rs1801157 polymorphism and reduced SLE risk was found under GA vs. GG model (OR = 0.84, 95% CI = 0.70–1.00). A similar result was also observed in Asian subgroup under the same comparison after stratification analysis by ethnicity (OR = 0.79, 95% CI = 0.63–1.00).

Materials and Methods

All included studies were retrieved from PubMed, EMBASE, Google Scholar Web and Chinese National Knowledge Infrastructure (CNKI). Odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated to appraise the strength of association between SDF-1 rs1801157 polymorphism and SLE risk. The stratification analysis was also performed according to ethnicity. In addition, heterogeneity was examined with Q test, and sensitivity analysis was used to test the stability of final results. Begg’s funnel plot and Egger’s test were adopted to evaluate publication bias.

Conclusions

SDF-1 rs1801157 polymorphism may not influence the risk of SLE. However, more studies with larger sample sizes involving different populations are needed to further explore this issue.

Increased chemokine (C-C motif) ligand 21 expression and its correlation with osteopontin in Graves' disease

Graves' disease (GD) is a chronic autoimmune process characterized by the production of auto-antibodies that presumably consequent to the lymphocytic infiltrates in the thyroid. Chemokine (C-C motif) ligand 21 (CCL21) is important for the circulation of CC-chemokine receptor 7 (CCR7)-expressing cells. Meanwhile, osteopontin (OPN) enhances the production of proinflammatory cytokines and chemokines through NF-κB and MAPK signaling pathways in GD. Although CCL21 has been reported to play a vital role in several autoimmune diseases, little is known about the relationship between CCL21 and GD development. This study aimed to detect the CCL21 level in GD and to examine the role of OPN in regulating CCL21 production. 40 initial GD patients, 15 euthyroid GD patients, 12 TRAb-negative GD patients, and 25 healthy control donors were recruited. CCL21 levels in plasma and culture supernatants were quantified by enzyme-linked immunosorbent assay (ELISA). CD4+ T cells were isolated from peripheral blood mononuclear cells using antibody-coated magnetic beads. Quantitative polymerase chain reaction was used to determine CCL21 expression levels in CD4+ T cells. We demonstrated for the first time that plasma CCL21 levels were overexpressed in GD patients and recovered in TRAb-negative GD patients. Moreover, CCL21 levels correlated with TRAb levels and plasma OPN concentrations. Furthermore, we demonstrated that recombinant OPN increased the expression of CCL21 in a dose- and time-dependent manner. These data indicated a clinical correlation between plasma CCL21 levels and GD. CCL21 could serve as a novel biomarker for GD as well as a potential target for TRAb-positive GD treatment.

Defining a functionally distinct subset of human memory CD4+ T cells that are CD25POS and FOXP3NEG

Surface expression of the IL-2 receptor α-chain (CD25) has been used to discriminate between CD4(+) CD25(HI) FOXP3(+) regulatory T (Treg) cells and CD4(+) CD25(NEG) FOXP3(-) non-Treg cells. However, this study reports that the majority of resting human memory CD4(+) FOXP3(-) T cells expresses intermediate levels of CD25 and that CD25 expression can be used to delineate a functionally distinct memory subpopulation. The CD25(NEG) memory T-cell population contains the vast majority of late differentiated cells that respond to antigens associated with chronic immune responses and are increased in patients with systemic lupus erythematosus (SLE). In contrast, the CD25(INT) memory T cells respond to antigens associated with recall responses, produce a greater array of cytokines, and are less dependent on costimulation for effector responses due to their expression of CD25. Lastly, compared to the CD25(NEG) and Treg-cell populations, the CD25(INT) memory population is lost to a greater degree from the blood of cancer patients treated with IL-2. Collectively, these results show that in humans, a large proportion of CD4(+) memory T cells express intermediate levels of CD25, and this CD25(INT) FOXP3(-) subset is a functionally distinct memory population that is uniquely affected by IL-2.

Increased expression of SLAM receptors SLAMF3 and SLAMF6 in systemic lupus erythematosus T lymphocytes promotes Th17 differentiation

Altered T cell function in systemic lupus erythematosus (SLE) is determined by various molecular and cellular abnormalities, including increased IL-17 production. Recent evidence suggests a crucial role for signaling lymphocyte activation molecules (SLAMs) in the expression of autoimmunity. In this study, we demonstrate that SLAMF3 and SLAMF6 expression is increased on the surface of SLE T cells compared with normal cells. SLAM coengagement with CD3 under Th17 polarizing conditions results in increased IL-17 production. SLAMF3 and SLAMF6 T cell surface expression and IL-17 levels significantly correlate with disease activity in SLE patients. Both naive and memory CD4(+) T cells produce more IL-17 in response to SLAM costimulation as compared with CD28 costimulation. In naive CD4(+) cells, IL-17 production after CD28 costimulation peaks on day 3, whereas costimulation with anti-SLAMF3 and anti-SLAMF6 Abs results in a prolonged and yet increasing production during 6 d. Unlike costimulation with anti-CD28, SLAM costimulation requires the presence of the adaptor molecule SLAM-associated protein. Thus, engagement of SLAMF3 and SLAMF6 along with Ag-mediated CD3/TCR stimulation represents an important source of IL-17 production, and disruption of this interaction with decoy receptors or blocking Abs should mitigate disease expression in SLE and other autoimmune conditions.

CXCR3, inflammation, and autoimmune diseases

CXCR3 is a G protein-coupled, seven-transmembrane receptor that binds and is activated by the three IFN-gamma-inducible chemokines of the CXC family named CXCL9, CXCL10, and CXCL11. These chemokines are not constitutively expressed but are up-regulated in a proinflammatory cytokine milieu. Consequently, their major function is to selectively recruit immune cells at inflammation sites, but they also play a role in angiogenesis mechanisms. In the last few years, strong experimental and clinical evidence has been obtained supporting the idea that the CXCR3 pathway is involved in the development of autoimmune diseases, especially by creating local amplification loops of inflammation in target organs, thereby inducing worsening of clinical manifestations. This article briefly reviews what we know today about the nature and functions of CXCR3, with special emphasis on its involvement in two main rheumatic systemic autoimmune diseases, namely rheumatoid arthritis and systemic lupus erythematosus.