Yuichiro Akiyama

Cell Adhesion Molecules Regulate Fibrotic Process via Th1/Th2/Th17 Cell Balance in a Bleomycin-Induced Scleroderma Model

Mice s.c. injected with bleomycin, an experimental model for human systemic sclerosis, develop skin and lung fibrosis, which is mediated by inflammatory cell infiltration. This process is highly regulated by multiple adhesion molecules and does not require Ag sensitization. To assess the role of adhesion molecules in this pathogenetic process, bleomycin-induced fibrosis was examined in mice lacking adhesion molecules. L-selectin and/or ICAM-1 deficiency inhibited skin and lung fibrosis with decreased Th2 and Th17 cytokines and increased Th1 cytokines. In contrast, P-selectin deficiency, E-selectin deficiency with or without P-selectin blockade, or P-selectin glycoprotein ligand 1 (PSGL-1) deficiency augmented the fibrosis in parallel with increased Th2 and Th17 cytokines and decreased Th1 cytokines. Furthermore, loss of L-selectin and/or ICAM-1 reduced Th2 and Th17 cell numbers in bronchoalveolar lavage fluid, whereas loss of P-selectin, E-selectin, or PSGL-1 reduced Th1 cell numbers. Moreover, Th1 cells exhibited higher PSGL-1 expression and lower expression of LFA-1, a ligand for ICAM-1, whereas Th2 and Th17 cells showed higher LFA-1 and lower PSGL-1 expression. This study suggests that L-selectin and ICAM-1 regulate Th2 and Th17 cell accumulation into the skin and lung, leading to the development of fibrosis, and that P-selectin, E-selectin, and PSGL-1 regulate Th1 cell infiltration, resulting in the inhibition of fibrosis.

Increased serum levels of soluble CD163 in patients with scleroderma.

CD163 is a 130-kDa, type I transmembrane protein belonging to group B of the cysteine-rich scavenger receptor family. Expression of CD163 is constitutive and/or induced by some stimuli on circulating monocytes and most tissue macrophages. An approximately 130-kDa soluble form of human CD163 is released from the cell surface by proteolysis after oxidative stress or inflammatory stimuli. Thus, an elevated level of circulating soluble CD163 (sCD163) has been reported in diabetes mellitus, which is one of the oxidative conditions. We have already acknowledged that scleroderma (SSc) is one of the oxidative conditions. Therefore, we conducted the measurement of serum sCD163 in SSc patients. After receiving the informed consents, 56 SSc patients were examined; 20 dermatomyositis patients were used as disease controls and 40 persons were used as healthy controls. Blood samples were collected, and the concentration of serum sCD163 was measured by ELISA (human CD163, R&D Systems). Other parameters in the blood of SSc patients were also examined. Statistical analyses were performed using Mann–Whitney U test, and the relationship between parameters was statistically examined by Spearmans rank test. Serum sCD163 levels were elevated in SSc patients compared with normal controls (p < 0.01), with similar levels between limited SSc and diffuse SSc patients. SSc patients with pulmonary fibrosis had increased serum levels of sCD163 than those without pulmonary fibrosis (p < 0.05). SSc patients with elevated sCD163 levels had increased serum levels of IgG than those with normal sCD163 levels (p < 0.05). Serum sCD163 levels correlated positively with pulsatility index in SSc patients (p = 0.0009, r = 0.534). These results suggest that oxidative stress may play an important role in immunological abnormalities, renal circulation, and pulmonary fibrosis of SSc.

Increased Serum Levels of Nε-(hexanoyl)lysine, A New Marker of Oxidative Stress, in Systemic Sclerosis

Objective To determine serum levels of Nɛ-(hexanoyl)lysine (HEL), a new marker of oxidative stress, and its clinical association in patients with systemic sclerosis (SSc). Methods Serum HEL levels from 26 patients with limited cutaneous SSc (lSSc), 34 with diffuse cutaneous SSc (dSSc), 20 with systemic lupus erythematosus (SLE), 20 with dermatomyositis (DM), and 40 healthy individuals were examined by enzyme linked immunosorbent assay. Results Serum HEL levels were elevated in patients with SSc compared with healthy controls (n = 40) with similar levels between patients with lSSc and dSSc (p < 0.0001). SSc patients with elevated HEL levels had increased serum levels of anti-agalactosyl IgG antibody, rheumatoid factor (RF), and IgM than those with normal HEL levels (p < 0.05). HEL levels correlated positively with anti-agalactosyl IgG antibody (p = 0.013, r = 0.408) and RF titer (p = 0.0028, r = 0.426). Conclusion Our results suggest that oxidative stress may play an important role in immunological abnormalities of SSc, especially in the production of autoantibodies including anti-agalactosyl IgG antibody and RF.

Yusho patients show increased serum IL-17, IL-23, IL-1β, and TNFα levels more than 40 years after accidental polychlorinated biphenyl poisoning.

Abstract The Yusho poisoning incident, caused by rice oil contaminated with polychlorinated biphenyls (PCBs), polychlorinated quarterphenyls (PCQs), and polychlorinated dibenzofurans (PCDFs) generated by heat-denatured PCBs, occurred in 1968 in western Japan. Although severe symptoms are rarely observed today, the levels of PCBs and PCDFs in the sera of Yusho patients remain high. The aryl hydrocarbon receptor (AhR), which also acts as a dioxin receptor, is a transcriptional regulator that mediates dioxin toxicity. Recent studies show that dioxin mediates its immune toxic effects via AhR and that AhR activation induces dysregulation of interleukin (IL)-17- producing T (TH17) cells. This study therefore hypothesized that Yusho patients would show dysregulated TH17 cell-mediated immune responses. To validate the hypothesis, levels of IL-17 and IL-22, each secreted by TH17 cells, along with IL-1β and IL-23 were measured in serum samples from 40 Yusho patients and 40 age-matched controls. Levels of tumor necrosis factor (TNF)-α potentially secreted by TH17 cell-stimulated neutrophils and macrophages were also measured. The results indicated that serum IL-17 levels, as well as those of IL-1β, IL-23, and TNFα, were significantly higher in Yusho patients than in controls. In contrast, serum IL-22 levels were significantly lower in the Yusho patients. These results suggest that Yusho patients have dysregulated TH17 cell-mediated immune responses that may be linked to inflammation.

The roles of P- and E-selectins and P-selectin glycoprotein ligand-1 in primary and metastatic mouse melanomas

BACKGROUND Malignant melanoma is often accompanied by a host response of inflammatory cell infiltration that is highly regulated by multiple adhesion molecules. OBJECTIVE To evaluate the role of adhesion molecules, including P-selectin glycoprotein ligand-1 (PSGL-1), P-selectin, and E-selectin. METHODS Subcutaneous primary growth and metastasis to the lung of B16 melanoma cells were examined in mice lacking PSGL-1, P-selectin, or E-selectin. RESULTS Primary subcutaneous growth of B16 melanoma was augmented by loss of PSGL-1, P-selectin, or E-selectin, while pulmonary metastasis was reduced by the loss of E-selectin. The enhancement of subcutaneous tumor growth was associated with a reduced accumulation of natural killer cells, CD4(+) T cells and CD8(+) T cells, while the attenuation of pulmonary metastasis was related to the numbers of CD8(+) T cells. The expressions of transforming growth factor (TGF)-β and interleukin (IL)-6 were correlated with primary subcutaneous growth; TGF-β, IL-6, and interferon-γ were related to number of metastatic lung nodules. Cytotoxicity against melanoma cells in splenocytes and in tumor-draining lymph node cells were not defective by the absence of adhesion molecules, suggesting that the enhancement of tumor growth and metastasis caused by the loss of selectins results from an impaired migration of effector cells into the tissue. CONCLUSIONS The results indicate the complexity of anti-tumor responses mediated by adhesion molecules in primary subcutaneous tumors and pulmonary metastasis of murine experimental melanoma.

Exogenous application of hydrogen sulfide donor attenuates inflammatory reactions through the L-selectin-involved pathway in the cutaneous reverse passive Arthus reaction

H2S has been highlighted recently as an endogenous, gaseous signaling molecule, especially in inflammations. The deposition of IC induces an acute inflammatory response with tissue injury. To assess the roles of H2S in the IC‐induced diseases, the cutaneous, reverse passive Arthus reaction was conducted using NaHS as a H2S donor. Furthermore, we conducted similar experiments using selectin−/− mice to determine the involvement of selectin molecules in the H2S‐mediated pathway. Exogenous application of NaHS dramatically attenuated inflammatory reactions in WT mice associated with Arthus reaction. Namely, mRNA expressions of TNF‐α, IFN‐γ, and neutrophil numbers were reduced significantly in the lesional skins of NaHS‐treated WT mice relative to untreated ones. NaHS treatment significantly reduced these three parameters in the lesional skins of E‐ and P‐selectin−/− mice but not in those of L‐selectin−/− mice. Quite similar results were obtained in the blocking study using WT mice injected with mAb to E‐, P‐, and L‐selectin. Our results indicated that the exogenous application of NaHS attenuates inflammatory responses in reverse passive Arthus reaction through a L‐selectin‐involved pathway but not through E‐ or P‐selectin pathways.

Involvement of L-Selectin in Contact Hypersensitivity Responses Augmented by Auditory Stress

Stress affects the pathophysiology of cutaneous immune reactions, including contact hypersensitivity (CH) in individuals sensitized with sensitizing hapten, where local endothelial cell activation plays a critical role. To clarify the effects of stress in cutaneous immune reactions, we selected a CH model using annoying sound as a stress. Furthermore, we conducted the stress experiments by using selectin-deficient mice to determine the involvement of selectin molecules regarding local endothelial activation. Auditory stress augmented CH responses in the present study. Namely, ear thickness and mast cell numbers were significantly increased in stressed CH mice. mRNA expression of preprotachykinin-A, a precursor of substance-P; interferon-gamma; interleukin (IL)-4; IL-6; and tumor necrosis factor-alpha significantly increased in stressed CH mice. Furthermore, stressed L-selectin-deficient mice showed significant decreases in all parameters mentioned above relative to stressed wild-type mice in CH response. Meanwhile, treatment with anti-L-selectin Ab resulted in a significant decrease in ear thickness and mRNA levels of interferon-gamma, IL-4, IL-6, and tumor necrosis factor-alpha, but failed to significantly reduce preprotachykinin-A mRNA levels and mast cell numbers. Our results indicated that auditory stress enhances CH response and that the augmentation of this CH response might be mediated through L-selectin, but not through P- or E-selectin pathways.

Cold agglutinin disease-associated digital gangrene treated with plasmapheresis

Sir, Cold agglutinin disease (CAD) is a type of autoimmune hemolytic anemia. Cold agglutinins are usually immunoglobulin M (IgM) antibodies that bind to erythrocyte surface antigens at low temperatures. Primary cold agglutinin disease is characterized by synthesis of kappa monoclonal IgM antibodies by proliferating clonal B‐lymphocytes whereas in secondary disease, synthesis of polyclonal IgM cold agglutinins accompanies acute infections and malignant lymphoma. More than 90% of patients have cutaneous lesions such as reversible acrocyanosis, Raynaud’s phenomenon, and livedo reticularis.[1] Since agglutination is rapidly reversible on warming, cold agglutinins rarely cause permanent obstruction of blood vessels leading to digital gangrene.[2‐4]

Low Zone Tolerance Requires ICAM-1 Expression to Limit Contact Hypersensitivity Elicitation

Painting subsensitizing doses of contact sensitizers on skin (low-dose tolerization) induces antigen (Ag)-specific tolerance, known as low zone tolerance (LZT), which has been experimentally demonstrated by the inhibition of contact hypersensitivity (CHS). Although LZT resulted from the inhibition of the sensitization phase, the effects on the effector/elicitation phase remain unknown. L-selectin and ICAM-1 regulate leukocyte influx into inflamed tissues during the elicitation phase of CHS. LZT was investigated in mice lacking either L-selectin or ICAM-1 to evaluate the roles these leukocyte receptors play in LZT during the elicitation phase. Low-dose tolerization effectively suppressed CHS in wild-type and L-selectin-deficient mice, but not in ICAM-1-deficient mice. Low-dose-tolerized ICAM-1-deficient splenocytes effectively suppressed the elicitation phase in naive wild-type recipients. Sensitized ICAM-1-deficient splenocytes showed normal proliferative responses to the sensitizing Ag and generated normal CHS in wild-type recipients. Thus, ICAM-1 deficiency did not affect sensitization. LZT was associated with a lack of ICAM-1 upregulation after elicitation, suggesting a potentially mechanistic role for ICAM-1. The blockade of IL-10, a possible mediator of LZT, produced by hapten-specific suppressor cells, abrogated LZT and restored ICAM-1 upregulation. These results indicate that low-dose tolerization controls CHS by abrogating ICAM-1 upregulation during the elicitation phase.