IP-10 and Type 1 Diabetes: A Question of Time and Location

Human immune phenotyping reveals accelerated aging in type 1 diabetes

The proportions and phenotypes of immune cell subsets in peripheral blood undergo continual and dramatic remodeling throughout the human life span, which complicates efforts to identify disease-associated immune signatures in type 1 diabetes (T1D). We conducted cross-sectional flow cytometric immune profiling on peripheral blood from 826 individuals (stage 3 T1D, their first-degree relatives, those with ≥2 islet autoantibodies, and autoantibody-negative unaffected controls). We constructed an immune age predictive model in unaffected participants and observed accelerated immune aging in T1D. We used generalized additive models for location, shape, and scale to obtain age-corrected data for flow cytometry and complete blood count readouts, which can be visualized in our interactive portal (ImmScape); 46 parameters were significantly associated with age only, 25 with T1D only, and 23 with both age and T1D. Phenotypes associated with accelerated immunological aging in T1D included increased CXCR3+ and programmed cell death 1-positive (PD-1+) frequencies in naive and memory T cell subsets, despite reduced PD-1 expression levels on memory T cells. Phenotypes associated with T1D after age correction were predictive of T1D status. Our findings demonstrate advanced immune aging in T1D and highlight disease-associated phenotypes for biomarker monitoring and therapeutic interventions.

Tryptophan metabolism promotes immune evasion in human pancreatic β cells

BACKGROUND

To resist the autoimmune attack characteristic of type 1 diabetes, insulin producing pancreatic β cells need to evade T-cell recognition. Such escape mechanisms may be conferred by low HLA class I (HLA-I) expression and upregulation of immune inhibitory molecules such as Programmed cell Death Ligand 1 (PD-L1).

METHODS

The expression of PD-L1, HLA-I and CXCL10 was evaluated in the human β cell line, ECN90, and in primary human and mouse pancreatic islets. Most genes were determined by real-time RT-PCR, flow cytometry and Western blot. Activator and inhibitor of the AKT signaling were used to modulate PD-L1 induction. Key results were validated by monitoring activity of CD8+ Jurkat T cells presenting β cell specific T-cell receptor and transduced with reporter genes in contact culture with the human β cell line, ECN90.

FINDINGS

In this study, we identify tryptophan (TRP) as an agonist of PD-L1 induction through the AKT signaling pathway. TRP also synergistically enhanced PD-L1 expression on β cells exposed to interferon-γ. Conversely, interferon-γ-mediated induction of HLA-I and CXCL10 genes was down-regulated upon TRP treatment. Finally, TRP and its derivatives inhibited the activation of islet-reactive CD8+ T cells by β cells.

INTERPRETATION

Collectively, our findings indicate that TRP could induce immune tolerance to β cells by promoting their immune evasion through HLA-I downregulation and PD-L1 upregulation.

FUNDING

Dutch Diabetes Research Foundation, DON Foundation, the Laboratoire d'Excellence consortium Revive (ANR-10-LABX-0073), Agence Nationale de la Recherche (ANR-19-CE15-0014-01), Fondation pour la Recherche Médicale (EQ U201903007793-EQU20193007831), Innovative Medicines InitiativeINNODIA and INNODIA HARVEST, Aides aux Jeunes Diabetiques (AJD) and Juvenile Diabetes Research Foundation Ltd (JDRF).

Immune-related toxicity and soluble profile in patients affected by solid tumors: a network approach

BACKGROUND

Immune checkpoint inhibitors (ICIs) have particular, immune-related adverse events (irAEs), as a consequence of interfering with self-tolerance mechanisms. The incidence of irAEs varies depending on ICI class, administered dose and treatment schedule. The aim of this study was to define a baseline (T0) immune profile (IP) predictive of irAE development.

METHODS

A prospective, multicenter study evaluating the immune profile (IP) of 79 patients with advanced cancer and treated with anti-programmed cell death protein 1 (anti-PD-1) drugs as a first- or second-line setting was performed. The results were then correlated with irAEs onset. The IP was studied by means of multiplex assay, evaluating circulating concentration of 12 cytokines, 5 chemokines, 13 soluble immune checkpoints and 3 adhesion molecules. Indoleamine 2, 3-dioxygenase (IDO) activity was measured through a modified liquid chromatography-tandem mass spectrometry using the high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) method. A connectivity heatmap was obtained by calculating Spearman correlation coefficients. Two different networks of connectivity were constructed, based on the toxicity profile.

RESULTS

Toxicity was predominantly of low/moderate grade. High-grade irAEs were relatively rare, while cumulative toxicity was high (35%). Positive and statistically significant correlations between the cumulative toxicity and IP10 and IL8, sLAG3, sPD-L2, sHVEM, sCD137, sCD27 and sICAM-1 serum concentration were found. Moreover, patients who experienced irAEs had a markedly different connectivity pattern, characterized by disruption of most of the paired connections between cytokines, chemokines and connections of sCD137, sCD27 and sCD28, while sPDL-2 pair-wise connectivity values seemed to be intensified. Network connectivity analysis identified a total of 187 statistically significant interactions in patients without toxicity and a total of 126 statistically significant interactions in patients with toxicity. Ninety-eight interactions were common to both networks, while 29 were specifically observed in patients who experienced toxicity.

CONCLUSIONS

A particular, common pattern of immune dysregulation was defined in patients developing irAEs. This immune serological profile, if confirmed in a larger patient population, could lead to the design of a personalized therapeutic strategy in order to prevent, monitor and treat irAEs at an early stage.

Cytokines and Lymphoid Populations as Potential Biomarkers in Locally and Borderline Pancreatic Adenocarcinoma

Despite its relative low incidence, PDAC is one of the most aggressive and lethal types of cancer, being currently the seventh leading cause of cancer death worldwide, with a 5-year survival rate of 10.8%. Taking into consideration the necessity to improve the prognosis of these patients, this research has been focused on the discovery of new biomarkers. For this purpose, patients with BL and resectable disease were recruited. Serum cytokines and growth factors were monitored at different time points using protein arrays. Immune cell populations were determined by flow cytometry in peripheral blood as well as by immunohistochemistry (IHC) in tumor tissues. Several cytokines were found to be differentially expressed between the study subgroups. In the BL disease setting, two different scores were proven to be independent prognostic factors for progression-free survival (PFS) (based on IL-10, MDC, MIF, and eotaxin-3) and OS (based on eotaxin-3, NT-3, FGF-9, and IP10). In the same context, CA19-9 was found to play a role as independent prognostic factor for OS. Eotaxin-3 and MDC cytokines for PFS, and eotaxin-3, NT-3, and CKβ8-1 for OS, were shown to be predictive biomarkers for nab-paclitaxel and gemcitabine regimen. Similarly, oncostatin, BDNF, and IP10 cytokines were proven to act as predictive biomarkers regarding PFS, for FOLFIRINOX regimen. In the resectable cohort, RANTES, TIMP-1, FGF-4, and IL-10 individually differentiated patients according to their cancer-associated survival. Regarding immune cell populations, baseline high levels of circulating B lymphocytes were related to a significantly longer OS, while these levels significantly decreased as progression occurred. Similarly, baseline high levels of helper lymphocytes (CD4+), low levels of cytotoxic lymphocytes (CD8+), and a high CD4/CD8 ratio, were related to a significantly longer PFS. Finally, high levels of CD4+ and CD8+ intratumoural infiltration was associated with significantly longer PFS. In conclusion, in this study we were able to identify several prognostic and predictive biomarker candidates in patients diagnosed of resectable or BL PDAC.

Increased spontaneous CCL2 (MCP-1) and CCL5 (RANTES) secretion in vitro in LADA compared to type 1 diabetes and type 2 diabetes: Action LADA 14

AIMS

Immune-mediated type 1 diabetes (T1D) in adulthood and latent autoimmune diabetes in adults (LADA) share similar pathological mechanisms but differ clinically in disease progression. The aim of this study was to acquire insights into spontaneous and stimulated chemokine secretion of immune cells in different diabetes types.

MATERIALS AND METHODS

We investigated in vitro spontaneous, mitogen (PI) and antigen (HSP60, p277, pGAD, pIA2) stimulated chemokine secretion of leucocytes from patients with T1D (n = 32), LADA (n = 22), type 2 diabetes (T2D; n = 49), and glucose-tolerant individuals (n = 13). Chemokine concentration in supernatants was measured for CCL2 (MCP-1), CXCL10 (IP10) and CCL5 (RANTES) using a multiplex bead array assay.

RESULTS

Spontaneous secretion of CCL2 and CCL5 were higher in LADA compared to T1D and T2D (all p < 0.05) while CXCL10 was similar in the groups. Mitogen-stimulated secretion of CCL2 in LADA was lower compared to T1D and T2D (all p < 0.05) while CXCL10 and CCL5 were similar in all groups. Upon stimulation with pIA2 the secretion of CCL2 in LADA was lower compared to T2D (p < 0.05). Spontaneous CXCL10 secretion in LADA was positively associated with body mass index (r²  = 0.35; p = 0.0035) and C-peptide (r²  = 0.30; p = 0.009).

CONCLUSIONS

Chemokine secretion is altered between different diabetes types. Increased spontaneous secretion of CCL2 and CCL5 and decreased secretion of CCL2, upon stimulation with PI and pIA2, in LADA compared to T1D and T2D could reflect altered immune responsiveness in LADA patients in association with their slower clinical progression compared to insulin dependence.

The modifying effect of nutritional factors on the association between IL1-β single nucleotide polymorphism and serum CXCL10 levels in young Canadian adults

BACKGROUND

Genetic and nutritional factors play an important role in inflammatory response and diseases. CXCL10 is a critical biomarker that is involved in multiple inflammatory diseases, and elevated levels of CXCL10 have been associated with the development of several chronic and infectious diseases. In contrast, micronutrients can attenuate inflammatory responses. Single nucleotide polymorphisms in the pro-inflammatory cytokine genes such as IL-1β at rs16944 contributed to a number of inflammatory disorders and may substantiate the convergance between chronic and infectious diseases.

AIM

This study aims to identify the modifying effect of nutritional factors on the association between IL-1β genotypes and CXCL10 levels.

METHODS

Participants (N = 386) were healthy males and females from the Toronto Nutrigenomics and Health study recruited from the University of Toronto. Levels of micronutrients and inflammatory markers were measured in plasma. IL-1β genotypes were extracted from the Affymetrix 6.0 SNP chip.

RESULTS

CXCL10 levels were not different across different IL-1β genotypes. Among those with the GA genotype, elevated CXCL10 levels were observed with higher than median ascorbic acid (β = 0.004 ± 0.002, P = 0.047) or higher than median vitamin D status (β = 0.003 ± 0.002, P = 0.044). Among participants with the AA genotype, subjects with low α-tocopherol status had elevated levels of CXCL10 (β = -0.016 ± 0.007, P = 0.012).

CONCLUSION

The association between IL-1β rs16944 genotype and CXCL10 levels was modified by the levels of ascorbic acid, α-tocopherol and vitamin D. These findings may aid in understanding the combined effect of genetic and dietary factors in the development of various infectious and chronic diseases in which IL-1β and CXCL10 may play an etiological role.

Viral Infections and Autoimmune Disease: Roles of LCMV in Delineating Mechanisms of Immune Tolerance

Viral infections are a natural part of our existence. They can affect us in many ways that are the result of the interaction between the viral pathogen and our immune system. Most times, the resulting immune response is beneficial for the host. The pathogen is cleared, thus protecting our vital organs with no other consequences. Conversely, the reaction of our immune system against the pathogen can cause organ damage (immunopathology) or lead to autoimmune disease. To date, there are several mechanisms for virus-induced autoimmune disease, including molecular mimicry and bystander activation, in support of the “fertile field” hypothesis (terms defined in our review). In contrast, viral infections have been associated with protection from autoimmunity through mechanisms that include Treg invigoration and immune deviation, in support of the “hygiene hypothesis”, also defined here. Infection with lymphocytic choriomeningitis virus (LCMV) is one of the prototypes showing that the interaction of our immune system with viruses can either accelerate or prevent autoimmunity. Studies using mouse models of LCMV have helped conceive and establish several concepts that we now know and use to explain how viruses can lead to autoimmune activation or induce tolerance. Some of the most important mechanisms established during the course of LCMV infection are described in this short review.

IP-10 and MCP-1 gene polymorphisms in Chinese patients with chronic immune thrombocytopenia

Aberrant Th1/Th2 polarization is considered to play a crucial role in the abnormal immune state of primary immune thrombocytopenia (ITP). IFN-γ-inducible protein of 10 kilodaltons (IP-10) and Monocyte chemoattractant protein-1 (MCP-1) gene are involved in enhancing the Th1 and Th2 immune response, respectively. In this study we investigated the distributions of IP-10 (-201 G/A) and MCP-1 (-2518 A/G) polymorphisms in 323 patients with chronic ITP and 255 healthy controls by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). The IP-10 and MCP-1 levels of blood serum from 79 adult ITP patients and 43 healthy controls were detected with ELISA. The frequency of AG + AA genotype in IP-10 (-201 G/A) was significantly higher in ITP patients than in controls, especially in female and adult patients. ITP patients showed higher IP-10 levels than normal controls. Moreover, both IP-10 (-201 G/A) heterozygote (GA) and homozygote minor allele (AA) patients had significantly increased IP-10 levels compared to homozygote genotype (GG) patients at diagnosis. No significant differences were revealed in genotypes and allele distributions of MCP-1 (-2518 A/G) between ITP patients and normal controls, as well as the MCP-1 levels. In conclusion, the -201 G/A polymorphism of IP-10 gene may be associated with the susceptibility of ITP in Chinese population.

β-Cell DNA Damage Response Promotes Islet Inflammation in Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease where pancreatic β-cells are destroyed by islet-infiltrating T cells. Although a role for β-cell defects has been suspected, β-cell abnormalities are difficult to demonstrate. We show a β-cell DNA damage response (DDR), presented by activation of the 53BP1 protein and accumulation of p53, in biopsy and autopsy material from patients with recently diagnosed T1D as well as a rat model of human T1D. The β-cell DDR is more frequent in islets infiltrated by CD45⁺ immune cells, suggesting a link to islet inflammation. The β-cell toxin streptozotocin (STZ) elicits DDR in islets, both in vivo and ex vivo, and causes elevation of the proinflammatory molecules IL-1β and Cxcl10. β-Cell-specific inactivation of the master DNA repair gene ataxia telangiectasia mutated (ATM) in STZ-treated mice decreases the expression of proinflammatory cytokines in islets and attenuates the development of hyperglycemia. Together, these data suggest that β-cell DDR is an early event in T1D, possibly contributing to autoimmunity.

Chemokines and Their Receptors in Islet Allograft Rejection and as Targets for Tolerance Induction

Graft rejection is a major barrier to successful outcome of transplantation surgery. Islet transplantation introduces insulin secreting tissue into type 1 diabetes mellitus recipients, relieving patients from exogenous insulin injection. However, insulitis of grafted tissue and allograft rejection prevent long-term insulin independence. Leukocyte trafficking is necessary for the launch of successful immune responses to pathogen or allograft. Chemokines, small chemotactic cytokines, direct the migration of leukocytes through their interaction with chemokine receptors found on cell surfaces of immune cells. Unique receptor expression of leukocytes, and the specificity of chemokine secretion during various states of immune response, suggest that the extracellular chemokine milieu specifically homes certain leukocyte subsets. Thus, only those leukocytes required for the current immune task are attracted to the inflammatory site. Chemokine blockade, using antagonists and monoclonal antibodies directed against chemokine receptors, is an emerging and specific immunosuppressive strategy. Importantly, chemokine blockade may potentiate tolerance induction regimens to be used following transplantation surgery, and prevent the need for life-long immunosuppression of islet transplant recipients. Here, the role for chemokine blockade in islet transplant rejection and tolerance is reviewed.

Spatiotemporal Dynamics of Insulitis in Human Type 1 Diabetes

Type 1 diabetes (T1D) is an auto-immune disease characterized by the selective destruction of the insulin secreting beta cells in the pancreas during an inflammatory phase known as insulitis. Patients with T1D are typically dependent on the administration of externally provided insulin in order to manage blood glucose levels. Whilst technological developments have significantly improved both the life expectancy and quality of life of these patients, an understanding of the mechanisms of the disease remains elusive. Animal models, such as the NOD mouse model, have been widely used to probe the process of insulitis, but there exist very few data from humans studied at disease onset. In this manuscript, we employ data from human pancreases collected close to the onset of T1D and propose a spatio-temporal computational model for the progression of insulitis in human T1D, with particular focus on the mechanisms underlying the development of insulitis in pancreatic islets. This framework allows us to investigate how the time-course of insulitis progression is affected by altering key parameters, such as the number of the CD20+ B cells present in the inflammatory infiltrate, which has recently been proposed to influence the aggressiveness of the disease. Through the analysis of repeated simulations of our stochastic model, which track the number of beta cells within an islet, we find that increased numbers of B cells in the peri-islet space lead to faster destruction of the beta cells. We also find that the balance between the degradation and repair of the basement membrane surrounding the islet is a critical component in governing the overall destruction rate of the beta cells and their remaining number. Our model provides a framework for continued and improved spatio-temporal modeling of human T1D.

CXCR3, CXCL10 and type 1 diabetes

Type 1 diabetes (T1D) is due to antigen-specific assaults on the insulin producing pancreatic β-cells by diabetogenic T-helper (Th)1 cells. (C-X-C motif) ligand (CXCL)10, an interferon-γ inducible Th1 chemokine, and its receptor, (C-X-C motif) receptor (CXCR)3, have an important role in different autoimmune diseases. High circulating CXCL10 levels were detected in new onset T1D patients, in association with a Th1 autoimmune response. Furthermore β-cells produce CXCL10, under the influence of Th1 cytokines, that suppresses their proliferation. Viral β-cells infections induce cytokines and CXCL10 expression, inducing insulin-producing cell failure in T1D. CXCL10/CXCR3 system plays a critical role in the autoimmune process and in β-cells destruction in T1D. Blocking CXCL10 in new onset diabetes seems a possible approach for T1D treatment.

Induction of an inflammatory loop by interleukin-1β and tumor necrosis factor-α involves NF-kB and STAT-1 in differentiated human neuroprogenitor cells

Proinflammatory cytokines secreted from microglia are known to induce a secondary immune response in astrocytes leading to an inflammatory loop. Cytokines also interfere with neurogenesis during aging and in neurodegenerative diseases. The present study examined the mechanism of induction of inflammatory mediators at the transcriptional level in human differentiated neuroprogenitor cells (NPCs). Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) induced the expression of cytokines and chemokines in differentiated human NPCs as shown by an immune pathway-specific array. Network motif (NM) analysis of these genes revealed 118 three-node NMs, suggesting complex interactions between inflammatory mediators and transcription factors. Immunofluorescent staining showed increases in the levels of IL-8 and CXCL10 proteins in neurons and glial cells. Findings from Taqman low density array suggested the synergistic actions of IL-1β and TNF-α in the induction of a majority of inflammatory genes by a mechanism involving NF-kB and STAT-1. Nuclear localization of these transcription factors in differentiated NPCs was observed following exposure to IL-1α and TNF-α. Further studies on CXCL10, a chemokine known to be elevated in the Alzheimer's brain, showed that TNF-α is a stronger inducer of CXCL10 promoter when compared to IL-1β. The synergy between these cytokines was lost when ISRE or kB elements in CXCL10 promoter were mutated. Our findings suggest that the activation of inflammatory pathways in neurons and astrocytes through transcription factors including NF-kB and STAT-1 play important roles in neuroglial interactions and in sustaining the vicious cycle of inflammatory response.

Anti-inflammatory properties of exenatide in human pancreatic islets

Exenatide is an analog of the incretin hormone glucagon-like peptide (GLP-1) that is used for the treatment of T2D for their metabolic effects. In addition to its insulinotropic effects, exenatide increases functional islet mass and improves their survival. Improved outcomes have been reported in recent clinical islet transplantation trials for the treatment of type 1 diabetes. The purpose of this study was to investigate whether exenatide has anti-inflammatory properties in human islets. Exenatide treatment improved islet function, significantly reduced content of inflammation-related molecules (tissue factor, IFN-γ, IL-17, IL-1β, and IL-2) and caspase 3 activation, whereas increased phosphorylation of ERK1/2, STAT3, and Akt in vitro. Immunostaining showed expression of GLP-1R in β-cells but not in α-cells. IL-1β colocalized with GLP-1R in β-cells. Induction of serine proteinase inhibitor 9 (PI-9) was detected after exposure of human islets to exenatide in vitro and after transplantation into immunodeficient mice. GLP-1 induced PI-9 expression in vitro but to a lower extent than exenatide. This effect was partially blocked by the antagonist exendin-9 in vitro. As assessed by immunostaining PI-9 is mostly expressed in β-cells but not in α-cells. In conclusion, we describe anti-inflammatory and cytoprotective properties of exenatide in human islets. Exenatide-mediated PI-9 expression, the only known granzyme B inhibitor, unveils potential immunoregulatory properties.

Small molecule CXCR3 antagonist NIBR2130 has only a limited impact on type 1 diabetes in a virus-induced mouse model

CXCL10 is one of the key chemokines involved in trafficking of autoaggressive T cells to the islets of Langerhans during the autoimmune destruction of beta cells in type 1 diabetes (T1D). Blockade of CXCL10 or genetic deletion of its receptor CXCR3 results in a reduction of T1D in animal models. As an alternative to the use of neutralizing monoclonal antibodies to CXCL10 or CXCR3 we evaluated the small molecule CXCR3 antagonist NIBR2130 in a virus-induced mouse model for T1D. We found that the overall frequency of T1D was not reduced in mice administered with NIBR2130. An initial slight delay of diabetes onset was not stable over time, because the mice turned diabetic upon removal of the antagonist. Accordingly, no significant differences were found in the islet infiltration rate and the frequency and activity of islet antigen-specific T cells between protected mice administered with NIBR2130 and control mice. Our data indicate that in contrast to direct inhibition of CXCL10, blockade of CXCR3 with the small molecule antagonist NIBR2130 has no impact on trafficking and/or activation of autoaggressive T cells and is not sufficient to prevent T1D.

The immunomodulatory role of syncytiotrophoblast microvesicles

Immune adaptation is a critical component of successful pregnancy. Of primary importance is the modification of cytokine production upon immune activation. With the discovery that normal pregnancy itself is a pro-inflammatory state, it was recognised that the classical Th1/Th2 cytokine paradigm, with a shift towards 'type 2' cytokine production (important for antibody production), and away from 'type 1' immunity (associated with cell mediated immunity and graft rejection), is too simplistic. It is now generally agreed that both arms of cytokine immunity are activated, but with a bias towards 'type 2' immunity. Many factors are released from the placenta that can influence the maternal cytokine balance. Here we focus on syncytiotrophoblast microvesicles (STBM) which are shed from the placenta into the maternal circulation. We show that STBM can bind to monocytes and B cells and induce cytokine release (TNFα, MIP-1α, IL-1α, IL-1β, IL-6, IL-8). Other cytokines are down-modulated, such as IP-10 which is associated with 'type 1' immunity. Therefore STBM may aid the 'type 2' skewed nature of normal pregnancy. We also observed that PBMC from third trimester normal pregnant women produce more TNFα and IL-6 in response to STBM than PBMC from non-pregnant women, confirming that maternal immune cells are primed by pregnancy, possibly through their interaction with STBM.

Enterovirus infection induces cytokine and chemokine expression in insulin-producing cells

Despite evidence supporting an association between enterovirus (EV) infection and type 1 diabetes, the etiological mechanism(s) for EV-induced beta cell destruction is(are) not well understood. In this study, the effects of Coxsackievirus B (CVB) 1-6 on cell lysis and cytokine/chemokine expression in the insulinoma-1 (INS-1) beta cell line were investigated. Cytolysis was assessed using tissue culture infectious dose 50 (TCID(50)). Quantitative RT-PCR was used to measure viral RNA and mRNA of cytokines interferon (IFN)-α, IFN-β, IFN-γ, tumor necrosis factor (TNF)-α, and chemokine (C-X-C motif) ligand 10 (CXCL10), chemokine (C-C motif) ligand 2 (CCL2), and chemokine (C-C motif) ligand 5 (CCL5) in infected INS-1 cells. CVB2, 4, 5, and 6 lysed and replicated in INS-1 cells; TCID(50) was lowest for CVB5 and highest for CVB6. IFN-γ, CXCL10, and CCL5 mRNA levels all increased significantly following infection with CVB2, 4, 5, and 6 (P<0.05). CCL2 mRNA increased with CVB2, 5, and 6 (P<0.05), IFN-α mRNA increased with CVB5 infection (P<0.05), while TNF-α mRNA and IFN-β mRNA (P<0.001) increased with CVB2 infection. Dose-dependent effects of infection on cytokine mRNA levels were observed for all (P<0.01) except IFN-γ. Following inoculation of INS-1 cells with CVB1 and 3, viral RNA was not detected and cytokine/chemokine mRNA levels were unchanged. In conclusion, CVB2, 4, 5, and 6 induce dose-dependent cytokine and chemokine mRNA production from INS-1 cells suggesting that pro-inflammatory cytokine and chemokine secretion by beta cells is a potential mechanism for EV-induced beta cell damage in type 1 diabetes.

Evidence for an antagonist form of the chemokine CXCL10 in patients chronically infected with HCV

Chronic infection with hepatitis C virus (HCV) is a major public health problem, with nearly 170 million infected individuals worldwide. Current treatment for chronic infection is a combination of pegylated IFN-α2 and ribavirin (RBV); however, this treatment is effective in fewer than 50% of patients infected with HCV genotype 1 or 4. Recent studies identified the chemokine CXCL10 (also known as IP-10) as an important negative prognostic biomarker. Given that CXCL10 mediates chemoattraction of activated lymphocytes, it is counterintuitive that this chemokine correlates with therapeutic nonresponsiveness. Herein, we offer new insight into this paradox and provide evidence that CXCL10 in the plasma of patients chronically infected with HCV exists in an antagonist form, due to in situ amino-terminal truncation of the protein. We further demonstrated that dipeptidyl peptidase IV (DPP4; also known as CD26), possibly in combination with other proteases, mediates the generation of the antagonist form(s) of CXCL10. These data offer what we believe to be the first evidence for CXCL10 antagonism in human disease and identify a possible factor contributing to the inability of patients to clear HCV.

Anti-inflammatory action of exendin-4 in human islets is enhanced by phosphodiesterase inhibitors: potential therapeutic benefits in diabetic patients

AIMS/HYPOTHESIS

Exendin-4, a glucagon-like peptide-1 (GLP-1) analogue, is reported to have modest anti-inflammatory effects in addition to that of improving beta cell survival. We therefore sought to determine whether exendin-4 decreases expression of the gene encoding chemokine (C-X-C motif) ligand (CXCL)10, which plays a role in initiating insulitis in type 1 diabetes.

METHODS

The expression of CXCL10 in human islets was determined at the mRNA level by real-time RT-PCR analysis and at the protein level by western blotting. The level of CXCL10 in culture medium was measured by ELISA. Pathway-specific gene expression profiling was carried out to determine the expression of a panel of genes encoding chemokines and cytokines in human islets exposed to cytokines.

RESULTS

IFN-γ induced expression of CXCL10 through activation of signal transducer and activator of transcription-1 (STAT-1). A combination of cytokines (IL-1β, TNF-α and IFN-γ) showed strong synergy in the induction of numerous chemokines and cytokines through nuclear factor kappa B and STAT-1. Exendin-4 suppressed basal expression of several inflammatory mediators. In combination with phosphodiesterase inhibitors, exendin-4 also decreased IFN-γ-induced CXCL10 expression in human islets and in MIN6 cells (a mouse beta cell line), and its secretion into the culture medium. Exendin-4 action was mimicked by forskolin, an activator of adenylyl cyclase, and by dibutyryl cyclic AMP. Protein kinase A was not involved in mediating exendin-4 action on CXCL10. The mechanism of exendin-4's anti-inflammatory action involved decreases in STAT-1 levels.

CONCLUSIONS/INTERPRETATION

These findings suggest that the GLP-1-cyclic AMP pathway decreases islet inflammation in addition to its known effects on beta cell survival.

CXCL10 promotes liver fibrosis by prevention of NK cell mediated hepatic stellate cell inactivation

Chemokines, such as CXCL10, promote hepatic inflammation in chronic or acute liver injury through recruitment of leukocytes to the liver parenchyma. The CXCL10 receptor CXCR3, which is expressed on a subset of leukocytes, plays an important part in Th1-dependent inflammatory responses. Here, we investigated the role of CXCL10 in chemically induced liver fibrosis. We used carbon tetrachloride (CCl(4)) to trigger chronic liver damage in wildtype C57BL/6 and CXCL10-deficient mice. Fibrosis severity was assessed by Sirius Red staining and intrahepatic leukocyte subsets were investigated by immunohistochemistry. We have further analyzed hepatic stellate cell (HSC) distribution and activation and investigated the effect of CXCL10 on HSC motility and proliferation. In order to demonstrate a possible therapeutic intervention strategy, we have examined the anti-fibrotic potential of a neutralizing anti-CXCL10 antibody. Upon CCl(4) administration, CXCL10-deficient mice showed massively reduced liver fibrosis, when compared to wildtype mice. CXCL10-deficient mice had less B- and T lymphocyte and dendritic cell infiltrations within the liver and the number and activity of HSCs was reduced. In contrast, natural killer (NK) cells were more abundant in CXCL10-deficient mice and granzyme B expression was increased in areas with high numbers of NK cells. Further detailed analysis revealed that HSCs express CXCR3, respond to CXCL10 and secrete CXCL10 when stimulated with IFNγ. Blockade of CXCL10 with a neutralizing antibody exhibited a significant anti-fibrotic effect. Our data suggest that CXCL10 is a pro-fibrotic factor, which participates in a crosstalk between hepatocytes, HSCs and immune cells. NK cells seem to play an important role in controlling HSC activity and fibrosis. CXCL10 blockade may constitute a possible therapeutic intervention for hepatic fibrosis.

Peripheral lymphocyte subset and serum cytokine profiles of patients with West syndrome

OBJECTIVE

To clarify the immune pathophysiology of West syndrome (WS).

STUDY DESIGN

We measured peripheral blood lymphocyte subset and serum cytokine profiles in 76 WS patients and 26 age-matched controls. Adrenocorticotropic hormone (ACTH) is one of the most effective therapy for WS and presumably immune-modulating; therefore, we compared the measured parameters between before ACTH (pre-ACTH) WS patients and controls, between cryptogenic and symptomatic WS patients before ACTH (pre-ACTH), and between before (pre-ACTH) and after (post-ACTH) ACTH WS patients. The post-ACTH group included those who received the last ACTH dose within 1 month of sampling.

RESULTS

CD3+ CD25+, CD19+, and CD19+ CD95+ cells were found to be significantly lower in the pre-ACTH group than in the controls. Interleukin (IL)-1 receptor antagonist (RA), 5, 6, and 15; eotaxin; basic fibroblast growth factor (bFGF); and interferon gamma-inducible protein (IP)-10 levels were higher in pre-ACTH group than in the controls. No significant differences were found between the pre-ACTH cryptogenic and symptomatic groups. CD4+ cells, CD3+ cells, CD4+/8+ ratio, IL-1 beta, IL-12, and macrophage inflammatory protein (MIP)-1 beta were significantly higher in pre-ACTH group than in the post-ACTH group.

CONCLUSIONS

Our study revealed immunological alterations in WS patients, and these responses were modified by ACTH therapy. Further study is needed to elucidate whether or how the immune system alteration is involved in the pathophysiology of WS.

Critical role for TNF in the induction of human antigen-specific regulatory T cells by tolerogenic dendritic cells

TNF is a pleiotropic cytokine with differential effects on immune cells and diseases. Anti-TNF therapy was shown to be effective in rheumatoid arthritis but proved inefficient or even detrimental in other autoimmune diseases. We studied the role of TNF in the induction of Ag-specific regulatory T cells (Tregs) by tolerogenic vitamin D3-modulated human dendritic cells (VD3-DCs), which previously were shown to release high amounts of soluble TNF (sTNF) upon maturation with LPS. First, production of TNF by modulated VD3-DCs was analyzed upon maturation with LPS or CD40L with respect to both secreted (cleaved) TNF (sTNF) and expression of the membrane-bound (uncleaved) form of TNF (mTNF). Next, TNF antagonists were tested for their effect on induction of Ag-specific Tregs by modulated DCs and the subsequent functionality of these Tregs. VD3-DCs expressed greater amounts of mTNF than did control DCs (nontreated DCs), independent of the maturation protocol. Inhibition of TNF with anti-TNF Ab (blocking both sTNF and mTNF) during the priming of Tregs with VD3-DCs prevented generation of Tregs and their suppression of proliferation of CD4(+) T cells. In contrast, sTNF receptor II (sTNFRII), mainly blocking sTNF, did not change the suppressive capacity of Tregs. Blocking of TNFRII by anti-CD120b Ab during Treg induction similarly abrogated their subsequent suppressive function. These data point to a specific role for mTNF on VD3-DCs in the induction of Ag-specific Tregs. Interaction between mTNF and TNFRII instructs the induction of suppressive Tregs by VD3-DCs. Anti-TNF therapy may therefore act adversely in different patients or disease pathways.

NOD1 contributes to mouse host defense against Helicobacter pylori via induction of type I IFN and activation of the ISGF3 signaling pathway

Nucleotide-binding oligomerization domain 1 (NOD1) is an intracellular epithelial cell protein known to play a role in host defense at mucosal surfaces. Here we show that a ligand specific for NOD1, a peptide derived from peptidoglycan, initiates an unexpected signaling pathway in human epithelial cell lines that results in the production of type I IFN. Detailed analysis revealed the components of the signaling pathway. NOD1 binding to its ligand triggered activation of the serine-threonine kinase RICK, which was then able to bind TNF receptor-associated factor 3 (TRAF3). This in turn led to activation of TANK-binding kinase 1 (TBK1) and IkappaB kinase epsilon (IKKepsilon) and the subsequent activation of IFN regulatory factor 7 (IRF7). IRF7 induced IFN-beta production, which led to activation of a heterotrimeric transcription factor complex known as IFN-stimulated gene factor 3 (ISGF3) and the subsequent production of CXCL10 and additional type I IFN. In vivo studies showed that mice lacking the receptor for IFN-beta or subjected to gene silencing of the ISGF3 component Stat1 exhibited decreased CXCL10 responses and increased susceptibility to Helicobacter pylori infection, phenotypes observed in NOD1-deficient mice. These studies thus establish that NOD1 can activate the ISGF3 signaling pathway that is usually associated with protection against viral infection to provide mice with robust type I IFN-mediated protection from H. pylori and possibly other mucosal infections.

Systemic and intrahepatic interferon-gamma-inducible protein 10 kDa predicts the first-phase decline in hepatitis C virus RNA and overall viral response to therapy in chronic hepatitis C

High systemic levels of interferon-gamma-inducible protein 10 kDa (IP-10) at onset of combination therapy for chronic hepatitis C virus (HCV) infection predict poor outcome, but details regarding the impact of IP-10 on the reduction of HCV RNA during therapy remain unclear. In the present study, we correlated pretreatment levels of IP-10 in liver biopsies (n = 73) and plasma (n = 265) with HCV RNA throughout therapy within a phase III treatment trial (DITTO-HCV). Low levels of plasma or intrahepatic IP-10 were strongly associated with a pronounced reduction of HCV RNA during the first 24 hours of treatment in all patients (P < 0.0001 and P = 0.002, respectively) as well as when patients were grouped as genotype 1 or 4 (P = 0.0008 and P = 0.01) and 2 or 3 (P = 0.002, and P = 0.02). Low plasma levels of IP-10 also were predictive of the absolute reduction of HCV RNA (P < 0.0001) and the maximum reduction of HCV RNA in the first 4 days of treatment (P < 0.0001) as well as sustained virological response (genotype 1/4; P < 0.0001). To corroborate the relationship between early viral decline and IP-10, pretreatment plasma samples from an independent phase IV trial for HCV genotypes 2/3 (NORDynamIC trial; n = 382) were analyzed. The results confirmed an association between IP-10 and the immediate reduction of HCV RNA in response to therapy (P = 0.006). In contrast, pretreatment levels of IP-10 in liver or in plasma did not affect the decline of HCV RNA between days 8 and 29, i.e., the second-phase decline, or later time points in any of these cohorts.

CONCLUSION

In patients with chronic hepatitis C, low levels of intrahepatic and systemic IP-10 predict a favorable first-phase decline of HCV RNA during therapy with pegylated interferon and ribavirin for genotypes of HCV.

Dipyrithione inhibits IFN-gamma-induced JAK/STAT1 signaling pathway activation and IP-10/CXCL10 expression in RAW264.7 cells

Objective

This study investigates the effects of dipyrithione (PTS2) on the expression of IP-10/CXCL10, which has been observed in a wide variety of chronic inflammatory disorders and autoimmune conditions.

Methods

RAW264.7 cells (a murine macrophage-like cell line) were cultured in the absence or in the presence of PTS2 (3–10 μM) together with or without IFN-γ (10 ng/ml). IP-10/CXCL10 expression was measured by specific enzyme-amplified immunoassays and reverse transcriptase-PCR (RT-PCR). Phosphorylation of JAK1, JAK2 and STAT1 were detected by Western blot analysis.

Results

We found that PTS2 inhibited IFN-γ-induced up-regulation of IP-10/CXCL10 protein level in a dose- and time-dependent manner in RAW264.7 cells. RT-PCR experiments showed that PTS2 suppressed IFN-γ-induced IP-10/CXCL10 expression at mRNA levels. Mechanistically, PTS2 prevented phosphorylation of JAK1, JAK2 and STAT1, but did not interfere with the p38 pathway. Furthermore, the inhibitory effect of PTS2 on IP-10/CXCL10 up-regulation was slightly stronger than JAK2 inhibitor AG490.

Conclusion

PTS2 inhibits IFN-γ-induced IP-10/CXCL10 expression in RAW264.7 cells by targeting the JAK/STAT1 signaling pathway, suggesting that PTS2 could exert anti-inflammatory effects through attenuating the formation of chemokine IP-10/CXCL10.

Enterovirus infection, CXC chemokine ligand 10 (CXCL10), and CXCR3 circuit: a mechanism of accelerated beta-cell failure in fulminant type 1 diabetes

OBJECTIVE

Fulminant type 1 diabetes is characterized by the rapid onset of severe hyperglycemia and ketoacidosis, with subsequent poor prognosis of diabetes complications. Causative mechanisms for accelerated beta-cell failure are unclear.

RESEARCH DESIGN AND METHODS

Subjects comprised three autopsied patients who died from diabetic ketoacidosis within 2-5 days after onset of fulminant type 1 diabetes. We examined islet cell status, including the presence of enterovirus and chemokine/cytokine/major histocompatibility complex (MHC) expressions in the pancreata using immunohistochemical analyses and RT-PCR.

RESULTS

Immunohistochemical analysis revealed the presence of enterovirus-capsid protein in all three affected pancreata. Extensive infiltration of CXCR3 receptor-bearing T-cells and macrophages into islets was observed. Dendritic cells were stained in and around the islets. Specifically, interferon-gamma and CXC chemokine ligand 10 (CXCL10) were strongly coexpressed in all subtypes of islet cells, including beta-cells and alpha-cells. No CXCL10 was expressed in exocrine pancreas. Serum levels of CXCL10 were increased. Expression of MHC class II and hyperexpression of MHC class I was observed in some islet cells.

CONCLUSIONS

These results strongly suggest the presence of a circuit for the destruction of beta-cells in fulminant type 1 diabetes. Enterovirus infection of the pancreas initiates coexpression of interferon-gamma and CXCL10 in beta-cells. CXCL10 secreted from beta-cells activates and attracts autoreactive T-cells and macrophages to the islets via CXCR3. These infiltrating autoreactive T-cells and macrophages release inflammatory cytokines including interferon-gamma in the islets, not only damaging beta-cells but also accelerating CXCL10 generation in residual beta-cells and thus further activating cell-mediated autoimmunity until all beta-cells have been destroyed.

Increased secretion of IP-10 from monocytes under hyperglycemia is via the TLR2 and TLR4 pathway

Among the chemokines, members of the CXC family include IP-10 (interferon-gamma induced protein of 10kDa). Elevated serum IP-10 levels have been shown in diabetes. However, there is a paucity of data examining the sources and regulation of IP-10 under hyperglycemic conditions and this was the overall aim of the study. Type 1 diabetes (T1DM) is a pro-inflammatory state. We previously demonstrated increased toll like receptor (TLR) 2 and 4 activation in monocytes of T1DM patients. Thus, we also examined the role of the TLR pathway in modulating IP-10 release from human monocytes under hyperglycemia. Also, circulating and monocytic levels of IP-10 in patients with T1DM with and without microvascular complications (T1DM-MV and T1DM) and controls (C) was assessed. Under HG, IP-10 mRNA and protein were significantly increased compared to normoglycemia. Incubation of monocytes with dominant negative Ikb but not control vector significantly abrogated HG-induced IP-10 release. Furthermore, both TLR2 siRNA as well as TLR4 siRNA, either alone or in combination significantly abrogated HG-induced IP-10 release. Serum and monocytic levels of IP-10 were significantly increased in T1DM and T1DM-MV compared to matched controls. Thus, we demonstrate increased circulating and monocytic IP-10 in T1DM. Down-regulation of TLR2 and TLR4 abrogates HG-induced IP-10 release via NF-kappaB inhibition.

Interleukin-21 is required for the development of type 1 diabetes in NOD mice

OBJECTIVE

Interleukin (IL)-21 is a type 1 cytokine that has been implicated in the pathogenesis of type 1 diabetes via the unique biology of the nonobese diabetic (NOD) mouse strain. The aim of this study was to investigate a causal role for IL-21 in type 1 diabetes.

RESEARCH DESIGN AND METHODS

We generated IL-21R-deficient NOD mice and C57Bl/6 mice expressing IL-21 in pancreatic beta-cells, allowing the determination of the role of insufficient and excessive IL-21 signaling in type 1 diabetes.

RESULTS

Deficiency in IL-21R expression renders NOD mice resistant to insulitis, production of insulin autoantibodies, and onset of type 1 diabetes. The lymphoid compartment in IL-21R-/- NOD is normal and does not contain an increased regulatory T-cell fraction or diminished effector cytokine responses. However, we observed a clear defect in autoreactive effector T-cells in IL-21R-/- NOD by transfer experiments. Conversely, overexpression of IL-21 in pancreatic beta-cells induced inflammatory cytokine and chemokines, including IL-17A, IL17F, IFN-gamma, monocyte chemoattractant protein (MCP)-1, MCP-2, and interferon-inducible protein-10 in the pancreas. The ensuing leukocytic infiltration in the islets resulted in destruction of beta-cells and spontaneous type 1 diabetes in the normally diabetes-resistant C57Bl/6 and NOD x C57Bl/6 backgrounds.

CONCLUSIONS

This work provides demonstration of the essential prodiabetogenic activities of IL-21 on diverse genetic backgrounds (NOD and C57BL/6) and indicates that IL-21 blockade could be a promising strategy for interventions in human type 1 diabetes.

Endocrine manifestations of hepatitis C virus infection

Chronic infection with hepatitis C virus (HCV) can result in both hepatic and extrahepatic disease and endocrine dysfunction represents an important class of HCV-related extrahepatic disease. The most frequently occurring--and clinically important--of these endocrine disorders are thyroid disease and type 2 diabetes mellitus. In this Review, we evaluate the evidence in support of a link between HCV infection and endocrine-system dysfunction, and discuss potential pathophysiological mechanisms. A meta-analysis of the literature has revealed significant associations between chronic HCV infection, thyroid autoimmunity and hypothyroidism. Furthermore, a high prevalence of thyroid cancer has been reported in HCV-positive patients. Several clinicoepidemiological studies have demonstrated that chronic HCV infection could lead to the development of type 2 diabetes mellitus, possibly as a result of HCV-induced metabolic disturbances. Some researchers have postulated that a type 1 T-helper -cell mediated immune response underpins the association of chronic HCV infection with endocrine disease. Indeed, the available data suggest that a common immunological, type 1 T-helper cell pattern of cytokine expression and activation (via interferon-gamma) could provide the pathophysiological basis for this association. Nonetheless, additional studies will be necessary to elucidate fully all the mechanisms involved in HCV-related endocrine dysfunction.

DNA microarray analysis for the identification of innate immune pathways implicated in virus-induced autoimmune diabetes

We have recently demonstrated that upregulation of the innate immune system plays a key role in KRV-induced autoimmune diabetes in the BBDR rat, but the nature of this proinflammatory reaction has not yet been addressed. Using a DNA microarray approach, we identified 569 genes upregulated in pancreatic lymph nodes following virus infection. Among the most highly activated are IL-1 pathways, IFN-gamma-induced chemokines, and genes associated with interferon production and signaling. Ex vivo and in vitro studies indicate that KRV upregulates proinflammatory cytokines and chemokines in B lymphocytes and Flt-3L-induced plasmacytoid DCs (pDCs). Finally, in contrast to KRV, infection of BBDR rats with the non-diabetogenic KRV homologue H-1 parvovirus fails to induce a robust proinflammatory response in pancreatic lymph nodes. Our findings provide new insights into KRV-induced innate immune pathways that may play a role in early mechanisms leading to islet inflammation and diabetes.

The target cell response to cytokines governs the autoreactive T cell repertoire in the pancreas of NOD mice

AIMS/HYPOTHESIS

The pancreatic beta cell response to cytokines is crucial for the development of type 1 diabetes in the NOD mouse. For example, beta cell production of suppressor of cytokine signalling-1 (SOCS-1) protects against diabetes. This finding and other recent studies indicated that cytokine-stressed beta cells might contribute to disease progression by affecting the pancreatic lymphocyte infiltrate. The aim of this study was to provide insight into how the beta cell influences the pancreas-infiltrating T cell repertoire.

METHODS

Lymphocytes isolated from Socs1-transgenic (tg) and non-tg NOD mice were analysed by flow cytometry. mRNA and protein levels in pancreatic islets were measured by real-time PCR and immunofluorescence analysis, respectively.

RESULTS

The percentages of regulatory T cells, total counts and ratios between infiltrating CD8+ and CD4+ T cells, and the expression of killer cell lectin-like receptor subfamily K, member 1 (NKG2D) on CD8+ T cells did not differ in pancreases from prediabetic Socs1-tg and non-tg NOD mice. However, a striking difference in the percentages of CD8+ T cells specific for glucose 6-phosphatase catalytic subunit-related protein 206-214 was found, showing that SOCS-1 prevents the accumulation of high percentages of self-reactive CD8+ T cells in the pancreas. It was also found that protection from diabetes in Socs1-tg NOD mice correlated with a reduced expression of Cxcl10 mRNA in IFN-gamma treated islets.

CONCLUSIONS/INTERPRETATION

This study highlights an important role for the beta cell in the local regulation of the diabetogenic process. By responding to the pro-inflammatory pancreas milieu it strongly influences the islet-reactive T cell repertoire in the pancreas.

CXCL10 impairs beta cell function and viability in diabetes through TLR4 signaling

In type 1 and type 2 diabetes (T1/T2DM), beta cell destruction by apoptosis results in decreased beta cell mass and progression of the disease. In this study, we found that the interferon gamma-inducible protein 10 plays an important role in triggering beta cell destruction. Islets isolated from patients with T2DM secreted CXCL10 and contained 33.5-fold more CXCL10 mRNA than islets from control patients. Pancreatic sections from obese nondiabetic individuals and patients with T2DM and T1DM expressed CXCL10 in beta cells. Treatment of human islets with CXCL10 decreased beta cell viability, impaired insulin secretion, and decreased insulin mRNA. CXCL10 induced sustained activation of Akt, JNK, and cleavage of p21-activated protein kinase 2 (PAK-2), switching Akt signals from proliferation to apoptosis. These effects were not mediated by the commonly known CXCL10 receptor CXCR3 but through TLR4. Our data suggest CXCL10 as a binding partner for TLR4 and as a signal toward beta cell failure in diabetes.

Enhanced expression of interferon-inducible protein-10 correlates with disease activity and clinical manifestations in systemic lupus erythematosus

Our objective was to investigate the serum levels of interferon-inducible protein-10 (IP-10) in systemic lupus erythematosus (SLE) and their correlation with disease activity and organ manifestations. Serum IP-10 levels were assessed in 464 SLE patients and 50 healthy donors. Disease activity was assessed by the revised SLE Activity Measure, and the concomitant active organ manifestations, anti-ds DNA antibody titres, complement levels and erythrocyte sedimentation rates recorded. Peripheral blood mononuclear cell (PBMC) synthesis of IP-10 in SLE patients and controls was determined by in vitro cultures stimulated with mitogen or lipopolysaccharide. Elevated serum IP-10 levels were observed in SLE patients, which were significantly higher in the presence of active haematological and mucocutaneous manifestations. SLE PBMCs exhibited enhanced spontaneous IP-10 production in vitro. Serial IP-10 levels correlated with longitudinal change in SLE activity, even at low levels where anti-dsDNA antibody and complement levels remain unchanged. These data demonstrate that IP-10 levels are increased in SLE and serum IP-10 may represent a more sensitive marker for monitoring disease activity than standard serological tests.

Immunopathogenesis of HCV-related endocrine manifestations in chronic hepatitis and mixed cryoglobulinemia

Hepatitis C Virus (HCV) is known to be responsible for both hepatic and extrahepatic diseases (HCV-related extrahepatic diseases = HCV-EHDs). The most important systemic HCV-EHDs are mixed cryoglobulinemia and lymphoproliferative disorders, while the most frequent and clinically important endocrine HCV-EHDs are thyroid disorders and type 2 diabetes mellitus (T2D). From a meta-analysis of the literature a significant association between HCV infection and thyroid autoimmunity and hypothyroidism has been reported. A high prevalence of thyroid cancer has been reported, too. Furthermore, several clinical epidemiologic studies have reported that HCV infection is associated to T2D. Many studies have linked Th1 immune response with HCV infection, thyroid autoimmunity, or diabetes. These findings suggest that a possible common immunological Th1 pattern could be the pathophysiological base of the association of HCV-EHDs, with thyroid autoimmunity and T2D. In fact, HCV infection of thyrocytes or beta-cells may act by upregulating CXCL10 secretion in these cells that is responsible for Th1 lymphocyte recruitment. Th1 response leads to increased IFNgamma and TNFalpha production that in turn stimulates CXCL10 secretion by the target cells, thus perpetuating the immune cascade. This process may lead to the appearance of thyroid autoimmune disorders or T2D in genetically predisposed subjects.

CXCL10/IP-10: a missing link between inflammation and anti-angiogenesis in preeclampsia?

OBJECTIVE

Interferon (IFN)-gamma inducible protein, CXCL10/IP-10, is a member of the CXC chemokine family with pro-inflammatory and anti-angiogenic properties. This chemokine has been proposed to be a key link between inflammation and angiogenesis. The aim of this study was to determine whether preeclampsia and delivery of a small for gestational age (SGA) neonate are associated with changes in maternal serum concentration of CXCL10/IP-10.

STUDY DESIGN

This cross-sectional study included patients in the following groups: (1) non-pregnant women (N = 49); (2) women with normal pregnancies (N = 89); (3) patients with preeclampsia (N = 100); and (4) patients who delivered an SGA neonate (N = 78). SGA was defined as birth weight below the 10th percentile. Maternal serum concentrations of CXCL10/IP-10 were measured by sensitive immunoassay. Non-parametric statistics were used for analysis.

RESULTS

(1) Patients with normal pregnancies had a significantly higher median serum concentration of CXCL10/IP-10 than non-pregnant women (median 116.1 pg/mL, range 40.7-1314.3 vs. median 90.3 pg/mL, range 49.2-214.7, respectively; p = 0.002); (2) no significant correlation was found between maternal serum concentration of CXCL10/IP-10 and gestational age (between 19 and 38 weeks); (3) there were no differences in median serum CXCL10/IP-10 concentrations between patients who delivered an SGA neonate and those with normal pregnancies (median 122.4 pg/mL, range 37.3-693.5 vs. median 116.1 pg/mL, range 40.7-1314.3, respectively; p > 0.05); (4) patients with preeclampsia had a higher median serum concentration of CXCL10/IP-10 than normal pregnant women (median 156.4 pg/mL, range 47.4-645.9 vs. median 116.1 pg/mL, range 40.7-1314.3, respectively; p < 0.05); (5) patients with preeclampsia had a higher median concentration of CXCL10/IP-10 than those who delivered an SGA neonate (median 156.4 pg/mL, range 47.4-645.9 vs. median 122.4 pg/mL, range 37.3-693.5, respectively; p < 0.05).

CONCLUSIONS

Patients with preeclampsia have significantly higher serum concentrations of CXCL10/IP-10 than both normal pregnant women and mothers who have SGA neonates. These results are likely to reflect an anti-angiogenic state as well as an enhanced systemic inflammatory response in patients with preeclampsia. Alternatively, since preeclampsia and SGA share several mechanisms of disease, it is possible that a higher concentration of this chemokine may contribute to the clinical presentation of preeclampsia in patients with a similar intrauterine insult.

Stromal cell-derived factor-1/CXCL12 stimulates chemorepulsion of NOD/LtJ T-cell adhesion to islet microvascular endothelium

OBJECTIVE

Diabetogenic T-cell recruitment into pancreatic islets facilitates beta-cell destruction during autoimmune diabetes, yet specific mechanisms governing this process are poorly understood. The chemokine stromal cell-derived factor-1 (SDF-1) controls T-cell recruitment, and genetic polymorphisms of SDF-1 are associated with early development of type 1 diabetes.

RESEARCH DESIGN AND METHODS

Here, we examined the role of SDF-1 regulation of diabetogenic T-cell adhesion to islet microvascular endothelium. Islet microvascular endothelial cell monolayers were activated with tumor necrosis factor-alpha (TNF-alpha), subsequently coated with varying concentrations of SDF-1 (1-100 ng/ml), and assayed for T-cell/endothelial cell interactions under physiological flow conditions.

RESULTS

TNF-alpha significantly increased NOD/LtJ T-cell adhesion, which was completely blocked by SDF-1 in a dose-dependent manner, revealing a novel chemorepulsive effect. Conversely, SDF-1 enhanced C57BL/6J T-cell adhesion to TNF-alpha-activated islet endothelium, demonstrating that SDF-1 augments normal T-cell adhesion. SDF-1 chemorepulsion of NOD/LtJ T-cell adhesion was completely reversed by blocking G(i)alpha-protein-coupled receptor activity with pertussis toxin. CXCR4 protein expression was significantly decreased in NOD/LtJ T-cells, and inhibition of CXCR4 activity significantly reversed SDF-1 chemorepulsive effects. Interestingly, SDF-1 treatment significantly abolished T-cell resistance to shear-mediated detachment without altering adhesion molecule expression, thus demonstrating decreased integrin affinity and avidity.

CONCLUSIONS

In this study, we have identified a previously unknown novel function of SDF-1 in negatively regulating NOD/LtJ diabetogenic T-cell adhesion, which may be important in regulating diabetogenic T-cell recruitment into islets.

Recent enterovirus infection in type 1 diabetes: evidence with a novel IgM method

Enterovirus (EV) infection has been associated with Type 1 (T1D) diabetes and on a few occasions virus could be isolated at onset of the disease. Using two such isolates as antigens in a quantitative PCR enhanced immunoassay (T1D-EV-QPIA) we have measured IgM antibodies against such potentially diabetogenic viruses in serum from 33 newly diagnosed T1D children, 24 siblings, and 27 healthy children. Sera were also analysed with regard to autoantibodies against GAD65, the cytokine TNF-alpha and the chemokine IP-10. EV-RNA detection was performed on peripheral blood mononuclear cells (PBMC). IgM antibodies against this "new" EV antigen were more frequent in serum from T1D children than in serum from siblings and/or controls (P < 0.001). EV-RNA was detected more frequently in PBMC from T1D children than in healthy control children (P < 0.001) and also compared to the siblings (P < 0.003). The cytokine TNF-alpha was less frequently detected in serum from the T1D children compared with serum from siblings and/controls (P < 0.001). A positive correlation was found between the results obtained with the T1D-EV-QPIA and the EV-PCR (P < 0.001). These findings are in line with earlier findings of an increased frequency of enteroviral infections in newly diagnosed T1D patients. In addition, we found that T1D children at onset of the disease had lower frequencies of the chemokine TNF-alpha in their serum than age- and sex-matched controls had, suggesting an impaired immune response.

Allogeneic islet transplantation

Significant progress has been made in the field of beta-cell replacement therapies by islet transplantation in patients with unstable Type 1 diabetes mellitus (T1DM). Recent clinical trials have shown that islet transplantation can reproducibly lead to insulin independence when adequate islet numbers are implanted. Benefits include improvement of glycemic control, prevention of severe hypoglycemia and amelioration of quality of life. Numerous challenges still limit this therapeutic option from becoming the treatment of choice for T1DM. The limitations are primarily associated with the low islet yield of human pancreas isolations and the need for chronic immunosuppressive therapies. Herein the authors present an overview of the historical progress of islet transplantation and outline the recent advances of the field. Cellular therapies offer the potential for a cure for patients with T1DM. The progress in beta-cell replacement treatment by islet transplantation as well as those of emerging immune interventions for the restoration of self tolerance justify great optimism for years to come.

Role of chemokines in endocrine autoimmune diseases

Chemokines are a group of peptides of low molecular weight that induce the chemotaxis of different leukocyte subtypes. The major function of chemokines is the recruitment of leukocytes to inflammation sites, but they also play a role in tumoral growth, angiogenesis, and organ sclerosis. In the last few years, experimental evidence accumulated supporting the concept that interferon-gamma (IFN-gamma) inducible chemokines (CXCL9, CXCL10, and CXCL11) and their receptor, CXCR3, play an important role in the initial stage of autoimmune disorders involving endocrine glands. The fact that, after IFN-gamma stimulation, endocrine epithelial cells secrete CXCL10, which in turn recruits type 1 T helper lymphocytes expressing CXCR3 and secreting IFN-gamma, thus perpetuating autoimmune inflammation, strongly supports the concept that chemokines play an important role in endocrine autoimmunity. This article reviews the recent literature including basic science, animal models, and clinical studies, regarding the role of these chemokines in autoimmune endocrine diseases. The potential clinical applications of assaying the serum levels of CXCL10 and the value of such measurements are reviewed. Clinical studies addressing the issue of a role for serum CXCL10 measurement in Graves' disease, Graves' ophthalmopathy, chronic autoimmune thyroiditis, type 1 diabetes mellitus, and Addison's disease have been considered. The principal aim was to propose that chemokines, and in particular CXCL10, should no longer be considered as belonging exclusively to basic science, but rather should be used for providing new insights in the clinical management of patients with endocrine autoimmune diseases.

Interferons induce an antiviral state in human pancreatic islet cells

Enterovirus infections, in particular those with Coxsackieviruses, have been linked to the development of type 1 diabetes (T1D). Although animal models have demonstrated that interferons (IFNs) regulate virus-induced T1D by acting directly on the beta cell, little is known on the human pancreatic islet response to IFNs. Here we show that human islet cells respond to IFNs by expressing signature genes of antiviral defense. We also demonstrate that they express three intracellular sensors for viral RNA, the toll like receptor 3 (TLR3) gene, the retinoic acid-inducible gene I (RIG-I) and the melanoma differentiation-associated gene-5 (MDA-5), which induce type I IFN production in infected cells. Finally, we show for the first time that the IFN-induced antiviral state provides human islets with a powerful protection from the replication of Coxsackievirus. This may be critical for beta cell survival and protection from virus-induced T1D in humans.

Quantification of chemokines by real-time reverse transcriptase PCR: applications in type 1 diabetes

Type 1 diabetes is a T-cell mediated autoimmune disease, characterized by the destruction of insulin-producing pancreatic beta-cells. This review will discuss the role of chemokines in the recruitment of immune cells leading to the pathology of this disease. There will be a focus on the quantification of chemokines and chemokine receptors by the recently developed real-time reverse transcriptase PCR technique. Today, this technique is in widespread use for analysis of chemokines in cells, tissues and tissue biopsies. The minute amount of tissue needed for analysis, as well as the very high sensitivity of this method, make it the method of choice for analysis of chemokines, which are often expressed at very low levels in target tissues. However, validation and optimization of the technique is of crucial importance for obtaining reliable results.

Cure of chronic viral infection and virus-induced type 1 diabetes by neutralizing antibodies

The use of neutralizing antibodies is one of the most successful methods to interfere with receptor-ligand interactions in vivo. In particular blockade of soluble inflammatory mediators or their corresponding cellular receptors was proven an effective way to regulate inflammation and/or prevent its negative consequences. However, one problem that comes along with an effective neutralization of inflammatory mediators is the general systemic immunomodulatory effect. It is therefore important to design a treatment regimen in a way to strike at the right place and at the right time in order to achieve maximal effects with minimal duration of immunosuppression or hyperactivation. In this review we reflect on two examples of how short time administration of such neutralizing antibodies can block two distinct inflammatory consequences of viral infection. First, we review recent findings that blockade of IL-10/IL-10R interaction can resolve chronic viral infection and second, we reflect on how neutralization of the chemokine CXCL10 can abrogate virus-induced type 1 diabetes.

Induction of the chemokine interferon-gamma-inducible protein-10 in human pancreatic islets during enterovirus infection

AIMS/HYPOTHESIS

Enterovirus infections have long been suspected to be environmental factors that may cause type 1 diabetes, but the pathways leading from infection to beta cell destruction are still unknown. We therefore examined whether enterovirus infection of human islets leads to upregulation of interferon-gamma-inducible protein (IP-10, now known as chemokine [C-X-C motif] ligand 10 [CXCL10]), a chemokine important for the induction of insulitis.

METHODS

Isolated human islets were infected with three different strains of Coxsackie B4 virus. IP-10 expression and secretion from the infected human islets were then measured using RT-PCR and ELISA at several time points.

RESULTS

IP-10 was clearly upregulated in and secreted from human islets during enterovirus infection. This was demonstrated with three different strains of Coxsackie B4 virus, two of which are lytic to islets and one which is non-lytic and can establish a persistent infection in human islets.

CONCLUSIONS/INTERPRETATION

We propose that enterovirus-induced upregulation of IP-10 during infection of the islets in vivo is the first step towards destructive insulitis. Our findings support the idea that enterovirus infection triggers immune-mediated beta cell destruction, and for the first time suggest a possible mechanism behind enterovirus-induced diabetes.

Characteristics of Rat CD4+CD25+ T Cells and Their Ability to Prevent Not Only Diabetes But Also Insulitis in an Adoptive Transfer Model in BB Rats

Human and mouse CD4(+)CD25(+) T cells have been intensively studied through the last decade. However, little is known about this subset in other species. This study describes the phenotype of rat CD4(+)CD25(+) Foxp3(+) T cells and the site in which they exert regulation in a transfer-induced autoimmune diabetes model. Several proteins and mRNAs are up-regulated in unstimulated rat CD4(+)CD25(+) T cells compared with CD4(+)CD25(-) T cells, including Foxp3, Lag-3, CD80, interleukin 10 (IL-10) and CTLA-4. To investigate CD4(+)CD25(+) T cells in vivo, we transferred three million diabetogenic T cells either alone or in combination with two million CD4(+)CD25(+) T cells to 30-day-old BB rats. The pancreas and the pancreatic lymph nodes were examined as two potential regulatory sites. Time-course analysis of pancreatic histology following diabetogenic T-cell transfers revealed insulitis from about 14 days after transfer. By contrast, rats receiving both diabetogenic T cells and CD4(+)CD25(+) T cells had no insulitis at any time. Moreover, the frequency of diabetogenic T cells in the pancreatic lymph nodes 2 days after transfer was significantly reduced in rats receiving both subsets. These data indicate that the primary site of T-cell regulation is in the draining lymph nodes and not the pancreas in our model.

Cure of chronic viral infection and virus-induced type 1 diabetes by neutralizing antibodies

The use of neutralizing antibodies is one of the most successful methods to interfere with receptor-ligand interactions in vivo. In particular blockade of soluble inflammatory mediators or their corresponding cellular receptors was proven an effective way to regulate inflammation and/or prevent its negative consequences. However, one problem that comes along with an effective neutralization of inflammatory mediators is the general systemic immunomodulatory effect. It is, therefore, important to design a treatment regimen in a way to strike at the right place and at the right time in order to achieve maximal effects with minimal duration of immunosuppression or hyperactivation. In this review, we reflect on two examples of how short time administration of such neutralizing antibodies can block two distinct inflammatory consequences of viral infection. First, we review recent findings that blockade of IL-10/IL-10R interaction can resolve chronic viral infection and second, we reflect on how neutralization of the chemokine CXCL10 can abrogate virus-induced type 1 diabetes.

Profound reduction in T-helper (Th) 1 lymphocytes in peripheral blood from patients with concurrent type 1 diabetes and Graves' disease

Type 1 diabetes likely is mediated by T-helper (Th) 1 lymphocytes, while Graves' disease may involve Th2 predominance. We investigated the balance between Th1 and Th2 cells and between Th1- and Th2-associated chemokine receptor expression on peripheral lymphocytes in subjects including patients with coexisting type 1 diabetes and Graves' disease. Peripheral blood mononuclear cells of all subjects were examined by flow cytometry for intracellular cytokines (IFN-gamma for Th1; IL-4 for Th2) and expression of the chemokine receptors CXCR3 (Th1-associated) and CCR4 (Th2-associated). Plasma concentrations of interferon-inducible protein (IP)-10, a CXCR3 ligand, and thymus and activation-regulated chemokine (TARC), a CCR4 ligand, were measured by enzyme-linked immunosorbent assays. IFN-gamma producing-T lymphocytes were significantly fewer in patients with coexisting type 1 diabetes and Graves' disease (12.4 +/- 6.8%, n = 6) than in healthy control subjects (19.9 +/- 4.1%, n = 6; P < 0.01) or patients with type 2 diabetes (19.1 +/- 4.5%, n = 5; P < 0.05). We found no significant difference in IFN-gamma-producing T lymphocytes between healthy controls and patients with only type 1 diabetes (n = 8) or Graves' disease (n = 5). Plasma IP-10 concentrations were significantly higher in patients with coexisting type 1 diabetes and Graves' disease than in control subjects (106.3 +/- 30.48 vs. 66.7 +/- 25.3 pg/ml, P = 0.0343). Considering only patients with type 1 diabetes alone, duration of diabetes correlated positively with IFN-gamma-producing T lymphocytes (r = 0.773, P = 0.0242) and the ratio of CXCR3 to CCR4 receptor expression (r = 0.947, P = 0.0004). In conclusion, Th1-associated T lymphocytes were fewer in peripheral blood from patients having both type 1 diabetes and Graves' disease than in those with either disease alone. Numbers of peripheral Th1 lymphocytes increased with increasing time from onset of type 1 diabetes in patients with type 1 diabetes alone.

Chemokine Receptor CXCR3 Desensitization by IL-16/CD4 Signaling Is Dependent on CCR5 and Intact Membrane Cholesterol

Previous work has shown that IL-16/CD4 induces desensitization of both CCR5- and CXCR4-induced migration, with no apparent effect on CCR2b or CCR3. To investigate the functional relationship between CD4 and other chemokine receptors, we determined the effects of IL-16 interaction with CD4 on CXCR3-induced migration. In this study we demonstrate that IL-16/CD4 induced receptor desensitization of CXCR3 on primary human T cells. IL-16/CD4 stimulation does not result in surface modulation of CXCR3 or changes in CXCL10 binding affinity. This effect does require p56(lck) enzymatic activity and the presence of CCR5, because desensitization is not transmitted in the absence of CCR5. Treatment of human T cells with methyl-beta-cyclodextrin, a cholesterol chelator, prevented the desensitization of CXCR3 via IL-16/CD4, which was restored after reloading of cholesterol, indicating a requirement for intact cholesterol. These studies demonstrate an intimate functional relationship among CD4, CCR5, and CXCR3, in which CCR5 can act as an adaptor molecule for CD4 signaling. This process of regulating Th1 cell chemoattraction may represent a mechanism for orchestrating cell recruitment in Th1-mediated diseases.

Inhibition of chemokine expression in rat inflamed paws by systemic use of the antihyperalgesic oxidized ATP

Background

We previously showed that local use of periodate oxidized ATP (oATP, a selective inhibitor of P2X7 receptors for ATP) in rat paw treated with Freund's adjuvant induced a significant reduction of hyperalgesia Herein we investigate the role of oATP, in the rat paws inflamed by carrageenan, which mimics acute inflammation in humans.

Results

Local, oral or intravenous administration of a single dose of oATP significantly reduced thermal hyperalgesia in hind paws of rats for 24 hours, and such effect was greater than that induced by diclofenac or indomethacin. Following oATP treatment, the expression of the pro-inflammatory chemokines interferon-gamma-inducible protein-10 (IP-10), mon ocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) within the inflamed tissues markedly decreased on vessels and infiltrated cells. In parallel, the immunohistochemical findings showed an impairment, with respect to the untreated rats, in P2X7 expression, mainly on nerves and vessels close to the site of inflammation. Finally, oATP treatment significantly reduced the presence of infiltrating inflammatory macrophages in the paw tissue.

Conclusion

Taken together these results clearly show that oATP reduces carrageenan-induced inflammation in rats.