The role of the CXCL10/CXCR3 system in type 1 diabetes

Islet-Resident Memory T Cells Orchestrate the Immunopathogenesis of Type 1 Diabetes through the FABP4-CXCL10 Axis

Type 1 diabetes (T1D) is a chronic disease characterized by self-destruction of insulin-producing pancreatic β cells by cytotoxic T cell activity. However, the pathogenic mechanism of T cell infiltration remains obscure. Recently, tissue-resident memory T (TRM) cells have been shown to contribute to cytotoxic T cell recruitment. TRM cells are found present in human pancreas and are suggested to modulate immune homeostasis. Here, the role of TRM cells in the development of T1D is investigated. The presence of TRM cells in pancreatic islets is observed in non-obese diabetic (NOD) mice before T1D onset. Mechanistically, elevated fatty acid-binding protein 4 (FABP4) potentiates the survival and alarming function of TRM cells by promoting fatty acid utilization and C-X-C motif chemokine 10 (CXCL10) secretion, respectively. In NOD mice, genetic deletion of FABP4 or depletion of TRM cells using CD69 neutralizing antibodies resulted in a similar reduction of pancreatic cytotoxic T cell recruitment, a delay in diabetic incidence, and a suppression of CXCL10 production. Thus, targeting FABP4 may represent a promising therapeutic strategy for T1D.

Cxcl10 chemokine induces migration of ING4-deficient breast cancer cells via a novel crosstalk mechanism between the Cxcr3 and Egfr receptors

The chemokine Cxcl10 has been associated with poor prognosis in breast cancer, but the mechanism is not well understood. Our previous study have shown that CXCL10 was repressed by the ING4 tumor suppressor, suggesting a potential inverse functional relationship. We thus investigated a role for Cxcl10 in the context of ING4 deficiencies in breast cancer. We first analyzed public gene expression datasets and found that patients with CXCL10-high/ING4-low expressing tumors had significantly reduced disease-free survival in breast cancer. In vitro, Cxcl10 induced migration of ING4-deleted breast cancer cells, but not of ING4-intact cells. Using inhibitors, we found that Cxcl10-induced migration of ING4-deleted cells required Cxcr3, Egfr, and the Gβγ subunits downstream of Cxcr3, but not Gαi. Immunofluorescent imaging showed that Cxcl10 induced early transient colocalization between Cxcr3 and Egfr in both ING4-intact and ING4-deleted cells, which recurred only in ING4-deleted cells. A peptide agent that binds to the internal juxtamembrane domain of Egfr inhibited Cxcr3/Egfr colocalization and cell migration. Taken together, these results presented a novel mechanism of Cxcl10 that elicits migration of ING4-deleted cells, in part by inducing a physical or proximal association between Cxcr3 and Egfr and signaling downstream via Gβγ. These results further indicated that ING4 plays a critical role in the regulation of Cxcl10 signaling that enables breast cancer progression.

Partners in Crime: Beta-Cells and Autoimmune Responses Complicit in Type 1 Diabetes Pathogenesis

Type 1 diabetes (T1D) is an autoimmune disease characterized by autoreactive T cell-mediated destruction of insulin-producing pancreatic beta-cells. Loss of beta-cells leads to insulin insufficiency and hyperglycemia, with patients eventually requiring lifelong insulin therapy to maintain normal glycemic control. Since T1D has been historically defined as a disease of immune system dysregulation, there has been little focus on the state and response of beta-cells and how they may also contribute to their own demise. Major hurdles to identifying a cure for T1D include a limited understanding of disease etiology and how functional and transcriptional beta-cell heterogeneity may be involved in disease progression. Recent studies indicate that the beta-cell response is not simply a passive aspect of T1D pathogenesis, but rather an interplay between the beta-cell and the immune system actively contributing to disease. Here, we comprehensively review the current literature describing beta-cell vulnerability, heterogeneity, and contributions to pathophysiology of T1D, how these responses are influenced by autoimmunity, and describe pathways that can potentially be exploited to delay T1D.

Designing an improved T-cell mobilising CXCL10 mutant through enhanced GAG binding affinity

The chemokine CXCL10 is released by a plethora of cells, including immune and metastatic cancer cells, following stimulation with interferon-gamma. It acts via its GPC receptor on T-cells attracting them to various target tissues. Glycosaminoglycans (GAGs) are regarded as co-receptors of chemokines, which enable the establishment of a chemotactic gradient for target cell migration. We have engineered human CXCL10 towards improved T-cell mobilisation by implementing a single site-directed mutation N20K into the protein, which leads to a higher GAG binding affinity compared to the wild type. Interestingly, this mutation not only increased T-cell migration in a transendothelial migration assay, the mutant intensified T-cell chemotaxis also in a Boyden chamber set-up thereby indicating a strong role of T-cell-localised GAGs on leukocyte migration. A CXCL10 mutant with increased GAG-binding affinity could therefore potentially serve as a T-cell mobiliser in pathological conditions where the immune surveillance of the target tissue is impaired, as is the case for most solid tumors.

Circulating anti-glutamic acid decarboxylase-65 antibody titers are positively associated with the capacity of insulin secretion in acute-onset type 1 diabetes with short duration in a Japanese population

Aims/Introduction

To elucidate the relationship between titers of islet autoantibodies, the C‐X‐C motif chemokine 10 – a circulating chemokine that activates T‐helper 1 cells leading to β‐cell destruction – and β‐cell function in type 1 diabetes.

Materials and Methods

In total, 58 type 1 diabetes patients positive for glutamic decarboxylase‐65 autoantibodies (GADA)‐radioimmunoassay (mean age 54.1 years; 27 acute‐onset cases and 31 slowly progressive cases) were enrolled; serum C‐X‐C motif chemokine 10 (n = 50), zinc transporter 8 autoantibodies (n = 50) and GADA (n = 58) by an enzyme‐linked immunosorbent assay, and insulinoma‐associated antigen‐2 autoantibodies by radioimmunoassay (n = 50) were measured. The ratio of 100 × random C‐peptide (ng/mL)‐to‐plasma glucose levels (mg/dL; C‐peptide index [CPI]) was measured.

Results

The CPI significantly decreased in both groups with the progression of disease duration. GADA titers by radioimmunoassay and enzyme‐linked immunosorbent assay were strongly correlated with the CPI in acute‐onset type 1 diabetes patients with a shorter disease duration (≤10 years), but not in those with a longer duration or slowly progressive type 1 diabetes. Neither insulinoma‐associated antigen‐2 nor zinc transporter 8 autoantibodies titers were correlated with the CPI. Serum C‐X‐C motif chemokine 10 levels in both groups were significantly higher than in non‐diabetic controls, and persisted at high levels even in those with chronic duration.

Conclusions

Among islet autoantibodies, the intensity of the humoral immune response, as defined by GADA titers, reflected the degree of residual β‐cell function in acute‐onset type 1 diabetes patients with short duration. Prolonged disease activity might accelerate β‐cell impairment in both subtypes of type 1 diabetes.

SLAMF7 Is a Critical Negative Regulator of IFN-α-Mediated CXCL10 Production in Chronic HIV Infection

Current advances in combined antiretroviral therapy have rendered HIV infection a chronic, manageable disease; however, the problem of persistent immune activation still remains despite treatment. The immune cell receptor SLAMF7 has been shown to be upregulated in diseases characterized by chronic immune activation. In this study, we studied the function of the SLAMF7 receptor in immune cells of HIV patients and the impacts of SLAMF7 signaling on peripheral immune activation. We observed increased frequencies of SLAMF7⁺ PBMCs in HIV⁺ individuals in a clinical phenotype-dependent manner, with discordant and long-term nonprogressor patients showing elevated SLAMF7 levels, and elite controllers showing levels comparable to healthy controls. We also noted that SLAMF7 was sensitive to IFN-⍺ stimulation, a factor elevated during HIV infection. Further studies revealed SLAMF7 to be a potent inhibitor of the monocyte-derived proinflammatory chemokine CXCL10 (IP-10) and other CXCR3 ligands, except in a subset of HIV⁺ patients termed SLAMF7 silent (SF7S). Studies utilizing small molecule inhibitors revealed that the mechanism of CXCL10 inhibition is independent of known SLAMF7 binding partners. Furthermore, we determined that SLAMF7 activation on monocytes is able to decrease their susceptibility to HIV-1 infection in vitro via downregulation of CCR5 and upregulation of the CCL3L1 chemokine. Finally, we discovered that neutrophils do not express SLAMF7, are CXCL10⁺ at baseline, are able to secrete CXCL10 in response to IFN-⍺ and LPS, and are nonresponsive to SLAMF7 signaling. These findings implicate the SLAMF7 receptor as an important regulator of IFN-⍺-driven innate immune responses during HIV infection.

The Expression of CXCL10/CXCR3 and Effect of the Axis on the Function of T Lymphocyte Involved in Oral Lichen Planus

The etiology of oral lichen planus (OLP) is still not clear. The purpose of this study was to explore the role of CXC chemokine receptor 3(CXCR3) and its ligand CXC motif chemokine 10(CXCL10) in the pathogenesis of OLP. We examined the expression of CXCR3 and CXCL10 in OLP patients and healthy controls by quantitative real-time PCR, Western blotting, ELISAs, and immunohistochemistry, respectively. Moreover, we detected the effects of CXCL10/CXCR3 axis on T lymphocyte migration, proliferation and apoptosis by Transwell assays, CCK8 assays, and flow cytometry. We found that the expression of CXCR3 and CXCL10 was significantly increased in OLP patients. In addition, T lymphocyte migration rate of CXCL10 stimulation group was significantly higher than that of control and CXCR3 antagonist groups. After antagonizing CXCR3, the migration ability of T lymphocytes was significantly decreased, and regardless of whether CXCL10 was added in the upper chamber culture medium, the number of migrating cells was similar. The addition of CXCL10 stimulant could stimulate the proliferation of T lymphocytes, but there was no significant difference compared with control group. After antagonizing CXCR3, the proliferation rate of T lymphocytes was significantly reduced. However, there were no significant differences in the apoptosis rates of T lymphocytes between CXCL10 stimulation group, antagonist CXCR3 group, and control group. Due to the change of expression in CXCR3 and CXCL10, and its interaction in mediating the directional migration of peripheral blood T lymphocytes, affecting the proliferation of T lymphocytes, it suggests that CXCL10/CXCR3 axis may be related to the immune mechanism of OLP.

High Risk First Degree Relatives of Type 1 Diabetics: An Association with Increases in CXCR3(+) T Memory Cells Reflecting an Enhanced Activity of Th1 Autoimmune Response

We analyzed the level of (a) CXCR3(+) (Th1) and CCR4(+) (Th2) T memory cells (b) interferon- γ inducible chemokine (IP-10)(Th1) and thymus and activation-regulated chemokine (TARC)(Th2), in 51 first degree relatives (FDRs) of type 1 diabetics (T1D) (17 high risk FDRs (GADA(+), IA-2(+)) and 34 low risk FDRs (GADA(-), IA-2(-))), 24 recent-onset T1D (R-T1D), and 18 healthy subjects. T memory subsets were analyzed by using four-color immunofluorescence staining and flowcytometry. IP-10 and TARC were determined by ELISA. High risk FDRs showed higher levels of CXCR3(+) and lower level of CCR4(+) T memory cells compared to low risk FDRs (64.98 ± 5.19 versus 42.13 ± 11.11; 29.46 ± 2.83 versus 41.90 ± 8.58%, resp., P < 0.001). Simultaneously, both IP-10 and TARC levels were increased in high risk versus low risk FDRs (160.12 ± 73.40 versus 105.39 ± 71.30; 438.83 ± 120.62 versus 312.04 ± 151.14 pg/mL, P < 0.05). Binary logistic regression analysis identified the level of CXCR3(+) T memory cells as predictors for high risk FDRs, together with high levels of IP-10. The results imply that, in FDRs, the risk for T1D might be strongly influenced by enhanced activity of Th1 and diminished activity of Th2 autoimmune response.

The lysine deacetylase inhibitor Givinostat inhibits β-cell IL-1β induced IL-1β transcription and processing

AIMS

Pro-inflammatory cytokines and chemokines, in particular IL-1β, IFNγ, and CXCL10, contribute to β-cell failure and loss in DM via IL-1R, IFNγR, and TLR4 signaling. IL-1 signaling deficiency reduces diabetes incidence, islet IL-1β secretion, and hyperglycemia in animal models of diabetes. Further, IL-1R antagonism improves normoglycemia and β-cell function in type 2 diabetic patients. Inhibition of lysine deacetylases (KDACi) counteracts β-cell toxicity induced by the combination of IL-1 and IFNγ and reduces diabetes incidence in non-obese diabetic (NOD) mice. We hypothesized that KDACi breaks an autoinflammatory circuit by differentially preventing β-cell expression of the β-cell toxic inflammatory molecules IL-1β and CXCL10 induced by single cytokines.

RESULTS

CXCL10 did not induce transcription of IL-1β mRNA. IL-1β induced β-cell IL-1β mRNA and both IL-1β and IFNγ individually induced Cxcl10 mRNA transcription. Givinostat inhibited IL-1β-induced IL-1β mRNA expression in INS-1 and rat islets and IL-1β processing in INS-1 cells. Givinostat also reduced IFNγ induced Cxcl10 transcription in INS-1 cells but not in rat islets, while IL-1β induced Cxcl10 transcription was unaffected in both.

MATERIALS AND METHODS

INS-1 cells and rat islets of Langerhans were exposed to IL-1β, IFNγ or CXCL10 in the presence or absence of KDACi (givinostat). Cytokine and chemokine mRNA expressions were quantified by real-time qPCR, and IL-1β processing by western blotting of cell lysates.

CONCLUSION/INTERPRETATION

Inhibition of β-cell IL-1β expression and processing and Cxcl10 transcription contributes to the β-cell protective actions of KDACi. In vitro β-cell destructive effects of CXCL10 are not mediated via IL-1β transcription. The differential proinflammatory actions of KDACs may be attractive novel drug targets in DM.

An autoimmune phenotype in vulvar lichen sclerosus and lichen planus: a Th1 response and high levels of microRNA-155

Vulvar lichen sclerosus and lichen planus are T-cell-mediated chronic skin disorders. Although autoimmunity has been suggested, the exact pathogenesis of these disorders is still unknown. Therefore, the aim of the current study was to investigate the molecular and immunological mechanisms critical to the pathogenesis of vulvar lichen sclerosus and lichen planus. By using gene expression profiling and real-time RT-PCR experiments, we demonstrated a significantly increased expression of the pro-inflammatory cytokines (IFNγ, CXCR3, CXCL9, CXCL10, CXCL11, CCR5, CCL4, and CCL5) specific for a Th1 IFNγ-induced immune response. In addition, BIC/microRNA-155 (miR-155)--a microRNA involved in regulation of the immune response--was significantly upregulated in lichen sclerosus and lichen planus (9.5- and 17.7-fold change, respectively). Immunohistochemistry showed a significant T-cell response, with pronounced dermal infiltrates of CD4(+), CD8(+), and FOXP3(+) cells. In conclusion, these data demonstrate an autoimmune phenotype in vulvar lichen sclerosus and lichen planus, characterized by increased levels of Th1-specific cytokines, a dense T-cell infiltrate, and enhanced BIC/miR-155 expression.

CXC chemokine ligand 10 DNA vaccination plus Complete Freund's Adjuvant reverses hyperglycemia in non-obese diabetic mice

OBJECTIVE

Complete Freund's Adjuvant (CFA) is known to arrest autoimmune diabetes development in non-obese diabetic (NOD) mice. However, CFA alone cannot induce effective remission in diabetic NOD mice. Previously, we reported that anti-CXC chemokine ligand 10 (CXCL10) antibody can promote beta-cell proliferation in NOD mice. In the present study, we aimed to examine whether anti-CXCL10 plus CFA treatment can effectively reverse autoimmune diabetes development.

METHODS

Systemic supply of anti-CXCL10 antibody by CXCL10 DNA vaccination in combination with CFA injection was performed in new-onset diabetic NOD mice. Remission rate of diabetes, histological characteristics of residual insulitis lesions, residual beta-cell mass, and regulatory T cell population in local pancreas were examined.

RESULTS

A high frequency of diabetes reversal was observed after combination treatment with anti-CXCL10 plus CFA. In mice showing diabetes reversal, residual beta-cell mass was significantly increased, and some beta-cells were in a proliferative state. Although systemic cytokine profiles were unaffected, the frequency of "hybrid regulatory T cells", i.e. regulatory T cells expressing CXCR3, was significantly increased in local pancreatic lesions. This was possibly associated with the regulation of anti-islet autoimmunity.

CONCLUSIONS

Anti-CXCL10 plus appropriate immune adjuvant therapy arrested, and reversed, type 1 diabetes development.