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Background: Macrophage-associated immune response plays an important role in myocardial ischemia/reperfusion (IR) injury. Dectin-1, expressed mainly on activated myeloid cells, is crucial for the regulation of immune homeostasis as a pattern recognition receptor. However, its effects and roles during the myocardial IR injury remain unknown., Methods: Genetic ablation, antibody blockade, or Dectin-1 activation, along with the adoptive bone marrow transfer chimeric model, was used to determine the functional significance of Dectin-1 in myocardial IR injury. Immune cell filtration and inflammation were examined by flow cytometry, quantitative real-time polymerase chain reaction, and immunohistochemistry. Moreover, Dectin-1 + cells were analyzed by flow cytometry in the blood of patients with ST-segment-elevation myocardial infarction and stable patients with normal coronary artery (control)., Results: We demonstrated that Dectin-1 expression observed on the bone marrow-derived macrophages is increased in the heart during the early phase after IR injury. Dectin-1 deficiency and antibody-mediated Dectin-1 inhibition led to a considerable improvement in cardiac function, accompanied by a reduction in cardiomyocyte apoptosis, which was associated with a decrease in M1 macrophage polarization and Ly-6C + monocyte and neutrophil infiltration. Activation of Dectin-1 with its agonist had the opposite effects. Furthermore, Dectin-1 contributed to neutrophil recruitment through the regulation of Cxcl1 and granulocyte colony-stimulating factor expression. In addition, Dectin-1-dependent interleukin-23/interleukin-1β production was shown to be essential for interleukin-17A expression by γδT cells, leading to neutrophil recruitment and myocardial IR injury. Furthermore, we demonstrated that circulating Dectin-1 + CD14 ++ CD16 - and Dectin-1 + CD14 ++ CD16 + monocyte levels were significantly higher in patients with ST-segment-elevation myocardial infarction than in controls and positively correlated with the severity of cardiac dysfunction., Conclusions: Our results reveal a crucial role of Dectin-1 in the process of mouse myocardial IR injury and provide a new, clinically significant therapeutic target.

Rationale: Macrophages are involved in wound healing after myocardial infarction (MI). The role of Dectin-2, a pattern recognition receptor mainly expressed on myeloid cells, in the infarct healing remains unknown., Objective: The aim of this study is to determine whether Dectin-2 signaling is involved in the healing process and cardiac remodeling after MI and to elucidate the underlying molecular mechanisms., Methods and Results: In a mouse model of permanent coronary ligation, Dectin-2, mainly expressed in macrophages, was shown to be increased in the early phase after MI. Dectin-2 knockout mice showed an improvement in the infarct healing and cardiac remodeling, compared with wild-type mice, which was demonstrated by significantly lower mortality because of cardiac rupture, increased wall thickness, and better cardiac function. Increased expression of α-smooth muscle actin and collagen I/III was observed, whereas the levels of matrix metalloproteinase-2 and matrix metalloproteinase-9 were decreased in the hearts of Dectin-2 knockout mice after MI. Dectin-2 deficiency inhibited the rate of apoptotic and necrotic cell death. However, Dectin-2 did not affect immune cell infiltration and macrophage polarization, but it led to a stronger activation of the Th1/interferon-γ immune reaction, through the enhancement of interleukin-12 production in the heart. Interferon-γ was shown to downregulate transforming growth factor-β-induced expression of α-smooth muscle actin and collagen I/III in isolated cardiac fibroblasts, leading to a decrease in migration and myofibroblast differentiation. Finally, Dectin-2 knockout improved myocardial ischemia-reperfusion injury and infarct healing., Conclusions: Dectin-2 leads to an increase in cardiac rupture, impairs wound healing, and aggravates cardiac remodeling after MI through the modulation of Th1 differentiation., (© 2017 American Heart Association, Inc.)

Background: Organ transplantation has seen an increased use of organs from older donors over the past decades in an attempt to meet the globally growing shortage of donor organs. However, inferior transplantation outcomes when older donor organs are used represent a growing challenge., Methods and Results: Here, we characterize the impact of donor age on solid-organ transplantation using a murine cardiac transplantation model. We found a compromised graft survival when older hearts were used. Shorter graft survival of older hearts was independent of organ age per se, because chimeric young or old organs repopulated with young passenger leukocytes showed comparable survival times. Transplantation of older organs triggered more potent alloimmune responses via intragraft CD11c+ dendritic cells augmenting CD4+ and CD8+ T-cell proliferation and proinflammatory cytokine production, particularly that of interleukin-17A. Of note, depletion of donor CD11c+ dendritic cells before engraftment, neutralization of interleukin-17A, or transplantation of older hearts into IL-17A(-/-) mice delayed rejection and reduced alloimmune responses to levels observed when young hearts were transplanted., Conclusions: These results demonstrate a critical role of old donor CD11c+ dendritic cells in mounting age-dependent alloimmune responses with an augmented interleukin-17A response in recipient animals. Targeting interleukin-17A may serve as a novel therapeutic approach when older organs are transplanted., (© 2015 American Heart Association, Inc.)

Rationale: Visceral adipose tissue-derived serine proteinase inhibitor (vaspin) is an adipokine identified from visceral adipose tissues of genetically obese rats., Objective: The role of vaspin in the diabetic vascular complications remains elusive, and we investigated the effects of vaspin on the vascular function under the diabetic milieu., Methods and Results: Adenovirus carrying the full length of the vaspin gene (Vaspin-Ad) ameliorated intimal proliferation of balloon-injured carotid arteries in diabetic Wistar rats. The expression of Ccl2, Pdgfb, and Pdgfrb genes was significantly reduced by the treatment of Vaspin-Ad. In cuff-injured femoral arteries, the intimal proliferation was ameliorated in vaspin transgenic (Vaspin Tg) mice. The application of recombinant vaspin and Vaspin-Ad promoted the proliferation and inhibited the apoptosis of human aortic endothelial cells. Adenovirus expressing vaspin with calmodulin and streptavidin-binding peptides was applied to human aortic endothelial cells, subjected to tandem tag purification and liquid chromatography-tandem mass spectrometry, and we identified GRP78 (78-kDa glucose-regulated protein) as an interacting molecule. The complex formation of vaspin, GRP78, and voltage-dependent anion channel on the plasma membrane was confirmed by the immunoprecipitation studies using aortas of Vaspin Tg mice. The binding assay using (125)I-vaspin in human aortic endothelial cells revealed high-affinity binding (dissociation constant = 0.565×10(-9) m) by the treatment of 5 μM thapsigargin, which recruited GRP78 from the endoplasmic reticulum to plasma membrane by inducing endoplasmic reticulum stress. In human aortic endothelial cells, vaspin induced phosphorylation of Akt and inhibited the kringle 5-induced Ca(2+) influx and subsequent apoptosis., Conclusions: Vaspin is a novel ligand for the cell-surface GRP78/voltage-dependent anion channel complex in endothelial cells and promotes proliferation, inhibits apoptosis, and protects vascular injuries in diabetes mellitus.

Objective: Interleukin(IL)-17A, an inflammatory cytokine, has been implicated in atherosclerosis, in which inflammatory cells within atherosclerotic plaques express IL-17A. However, its role in the development of atheroscelrosis remains to be controversial., Methods and Results: To directly examine the role of IL-17A in atherosclerosis, we generated apolipoprotein E (ApoE)/IL-17A double-deficient (ApoE(-/-)IL-17A(-/-)) mice. Mice were fed with high-fat diet (HFD) for either 8 or 16 weeks, both starting at ages of 6 to 8 weeks. We found that splenic CD4(+) T-cells produced high amounts of IL-17A in ApoE(-/-) mice after HFD feeding for 8 weeks. Atherosclerosis was significantly accelerated in HFD-fed ApoE(-/-)IL-17A(-/-) mice compared with ApoE(-/-) mice. Splenic CD4(+) T-cells of ApoE(-/-)IL-17A(-/-) mice after HFD feeding for 8 weeks, but not for 16 weeks, exhibited increased interferon gamma and decreased IL-5 production. Importantly, formation of vulnerable plaque as evidenced by reduced numbers of vascular smooth muscle cells and reduced type I collagen deposition in the plaque was detected in ApoE(-/-)IL-17A(-/-) mice after HFD feeding for 8 weeks., Conclusions: These results suggest that IL-17A regulates the early phase of atherosclerosis development after HFD feeding and plaque stability, at least partly if not all by modulating interferon gamma and IL-5 production from CD4(+) T-cells.

Background: Interleukin-17 (IL-17), which is predominantly produced by T helper 17 cells distinct from T helper 1 or T helper 2 cells, participates in the pathogenesis of infectious, autoimmune, and allergic disorders. However, the precise role in allograft rejection remains uncertain. In the present study, we investigated the role of IL-17 in acute allograft rejection using IL-17-deficient mice., Methods and Results: Donor hearts from FVB mice were heterotopically transplanted into either C57BL/6J-IL-17-deficient (IL-17(-/-)) or -wild-type mice. Allograft survival was significantly prolonged in IL-17(-/-) recipient mice due to reduced local inflammation accompanied by decreased inflammatory cell recruitment and cytokine/chemokine expression. IL-17(-/-) recipient mice exhibited decreased IL-6 production and reciprocally enhanced regulatory T cell expansion, suggesting a contribution of regulatory T cells to prolonged allograft survival. Indeed, allografts transplanted into anti-CD25 mAb-treated IL-17(-/-) recipient mice (regulatory T cell-depleted) developed acute rejection similar to wild-type recipient mice. Surprisingly, we found that gamma delta T cells rather than CD4(+) and CD8(+) T cells were key IL-17 producers in the allografts. In support, equivalent allograft rejection was observed in Rag-2(-/-) recipient mice engrafted with either wild-type or IL-17(-/-) CD4(+) and CD8(+) T cells. Finally, hearts transplanted into gamma delta T cell-deficient mice resulted in decreased allograft rejection compared with wild-type controls., Conclusions: During heart transplantation, (1) IL-17 is crucial for acceleration of acute rejection; (2) IL-17-deficiency enhances regulatory T cell expansion; and (3) gamma delta T cells rather than CD4(+) and CD8(+) T cells are a potential source of IL-17. IL-17 neutralization may provide a potential target for novel therapeutic treatment for cardiac allograft rejection.

Objective: Interleukin 17A (IL17A) is involved in many inflammatory processes, but its role in atherosclerosis remains controversial. We examined the role of IL17A in mouse and human atherosclerosis., Methods and Results: Atherosclerosis was induced in apolipoprotein E (ApoE)(-/-) and IL17A/ApoE(-/-) mice using high-fat feeding, angiotensin II infusion, or partial carotid ligation. In ApoE(-/-) mice, 3 months of high-fat diet induced interferon-γ production by splenic lymphocytes, and this was abrogated in IL17A/ApoE(-/-) mice. IL17A/ApoE(-/-) mice had reduced aortic superoxide production, increased aortic nitric oxide levels, decreased aortic leukocyte and dendritic cell infiltration, and reduced weight gain after a high-fat diet compared with ApoE(-/-) mice. Despite these favorable effects, IL17A deficiency did not affect aortic plaque burden after a high-fat diet or angiotensin II infusion. In a partial carotid ligation model, IL17A deficiency did not affect percentage of stenosis but reduced outward remodeling. In this model, neutralization of the related isoform, IL17F, in IL17A/ApoE(-/-) mice did not alter atherosclerosis. Finally, there was no correlation between IL17A levels and carotid intima-media thickness in humans., Conclusions: IL17 contributes to vascular and systemic inflammation in experimental atherosclerosis but does not alter plaque burden. The changes in plaque composition caused by IL17 might modulate plaque stability.

Rationale: One-third of myocarditis cases progresses to dilated cardiomyopathy (DCM), but the mechanisms controlling this process are largely unknown. CD4(+) T helper (Th)17 cells have been implicated in the pathogenesis of autoimmune diseases, but the role of Th17-produced cytokines during inflammation-induced cardiac remodeling has not been previously studied., Objective: We examined the importance of interleukin (IL)-17A in the progression of myocarditis to DCM using a mouse model., Methods and Results: Immunization of mice with myocarditogenic peptide in complete Freund's adjuvant induced the infiltration of IL-17A-producing Th17 cells into the inflamed heart. Unexpectedly, IL-17A-deficient mice developed myocarditis with similar incidence and severity compared to wild-type mice. Additionally, IL-17A deficiency did not ameliorate the severe myocarditis of interferon (IFN)gamma-deficient mice, suggesting that IL-17A plays a minimal role during acute myocarditis. In contrast, IL-17A-deficient mice were protected from postmyocarditis remodeling and did not develop DCM. Flow cytometric and cytokine analysis revealed an important role for IL-17A in heart-specific upregulation of IL-6, TNFalpha, and IL-1beta and the recruitment of CD11b(+) monocyte and Gr1(+) granulocyte populations into the heart. Furthermore, IL-17A-deficient mice had reduced interstitial myocardial fibrosis, downregulated expression of matrix metalloproteinase-2 and -9 and decreased gelatinase activity. Treatment of BALB/c mice with anti-IL-17A monoclonal antibody administered after the onset of myocarditis abrogated myocarditis-induced cardiac fibrosis and preserved ventricular function., Conclusions: Our findings reveal a critical role for IL-17A in postmyocarditis cardiac remodeling and the progression to DCM. Targeting IL-17A may be an attractive therapy for patients with inflammatory dilated cardiomyopathy.

Objective: Interleukin-1 receptor antagonist (IL-1Ra), one of the most important antiinflammatory cytokines, is crucial for homeostasis of the immune system. However, the role of IL-1Ra in aortic valve stenosis (AS) remains poorly understood [corrected]., Methods and Results: IL-1Ra-deficient (IL-1Ra(-/-)) mice on the BALB/c background showed increased aortic valve leaflet thickness compared to wild-type mice at the age of 12 weeks (P<0.001). We used peripheral T-cell transplantation to examine the role of T cells in the development of AS. T cells from IL-1Ra(-/-) but not from wild-type mice induced increased aortic valve thickness in nu/nu mice. Moreover, IL-1Ra(-/-) T cells produced much higher levels of tumor necrosis factor (TNF)-alpha in culture supernatants after anti-CD3 antibody stimulation compared to wild-type mice (P<0.001). Finally, we studied the role of TNF-alpha in the development of AS in IL-1Ra(-/-) mice by generating double-gene-deficient (TNF-alpha(-/-)/IL-1Ra(-/-)) mice. Interestingly, TNF-alpha(-/-)/IL-1Ra(-/-) mice did not have AS., Conclusions: IL-1Ra deficiency in inflammatory cells induced aortic valve inflammation and TNF-alpha participates importantly in the development of AS in IL-1Ra(-/-) mice.

The discovery of bone marrow-derived endothelial progenitors in the peripheral blood has promoted intensive studies on the potential of cell therapy for various human diseases. Accumulating evidence has suggested that implantation of bone marrow mononuclear cells effectively promotes neovascularization in ischemic tissues. It has also been reported that the implanted cells are incorporated not only into the newly formed vessels but also secrete angiogenic factors. However, the mechanism by which cell therapy improves tissue ischemia remains obscure. We enrolled 29 "no-option" patients with critical limb ischemia and treated ischemic limbs by implantation of peripheral mononuclear cells. Cell therapy using peripheral mononuclear cells was very effective for the treatment of limb ischemia, and its efficacy was associated with increases in the plasma levels of angiogenic factors, in particular interleukin-1beta (IL-1beta). We then examined an experimental model of limb ischemia using IL-1beta-deficient mice. Implantation of IL-1beta-deficient mononuclear cells improved tissue ischemia as efficiently as that of wild-type cells. Both wild-type and IL-1beta-deficient mononuclear cells increased expression of IL-1beta and thus induced angiogenic factors in muscle cells of ischemic limbs to a similar extent. In contrast, inability of muscle cells to secrete IL-1beta markedly reduces induction of angiogenic factors and impairs neovascularization by cell implantation. Implanted cells do not secret angiogenic factors sufficient for neovascularization but, instead, stimulate muscle cells to produce angiogenic factors, thereby promoting neovascularization in ischemic tissues. Further studies will allow us to develop more effective treatments for ischemic vascular disease.

Objective: Interleukin (IL)-1 plays an important role in atherosclerosis. IL-1 receptor antagonist (IL-1Ra) is an endogenous inhibitor of IL-1. However, the role of IL-1Ra in the development of atherosclerosis is poorly understood., Methods and Results: Mice that lacked IL-1Ra (IL-1Ra-/-) were crossed with apolipoprotein E-deficient (E-/-) mice and formation of atherosclerotic lesions was analyzed after 16 weeks or 32 weeks consumption of a normal chow diet. This study focused on the comparison of atherosclerotic lesion between IL-1Ra+/+/apoE-/- (n=12) and IL-1Ra(+/-)/apoE-/- mice (n=12), because of the significantly leaner phenotype in IL-1Ra-/-/apoE-/- mice compared with the others. Interestingly, atherosclerotic lesion size in IL-1Ra+/-/apoE-/- mice at age 16 weeks was significantly increased (30%) compared with IL-1Ra+/+/apoE-/- mice (P<0.05). At 32 weeks, the differences of lesion size between these mice failed to achieve statistical significance. However, immunostaining demonstrated an 86% (P<0.0001) increase in the MOMA-2-stained lesion area of IL-1Ra+/-/apoE-/- mice. In addition, alpha-actin staining in these lesions was significantly decreased (-15%) compared with those in IL-1Ra+/+/apoE-/- mice (P<0.05)., Conclusions: These results suggest an important role of IL-1Ra in the suppression of lesion development during early atherogenesis and furthermore indicate its role in the modulation of plaque composition.

Background: The cytokine interleukin (IL)-1 is an important mediator of inflammation and cardiovascular disease. Activity of this cytokine is modulated endogenously via the IL-1 receptor antagonist (IL-1Ra). The role of IL-1Ra in neointima formation after injury, however, is poorly understood., Methods and Results: Using IL-1Ra-deficient (IL-1Ra-/-; backcrossed 8 generations into the C57BL/6J background) and wild-type (IL-1Ra+/+) mice, we investigated neointimal formation 3 weeks after femoral artery injury induced by an external vascular cuff model. Intima and media thicknesses were measured, and the intima/media ratio was calculated. The mean intimal thickness and the intima/media ratio of IL-1Ra-/- mice increased by 249% (31.8+/-2.9 microm [n=10] versus 9.1+/-0.7 microm [n=10]; P<0.0001) and 257% (2.5+/-0.2 versus 0.7+/-0.1; P<0.0001), respectively, compared with IL-1Ra+/+ mice. No significant differences were observed in the medial thickness. Control immunostaining for IL-1Ra in injured vessels localized IL-1beta and the endogenous inhibitor in the endothelium and inflammatory cells of the adventitia in IL-1Ra+/+ but not IL-1Ra-/- mice., Conclusions: The absence of IL-1Ra promotes neointimal formation in mice after injury. These results suggest that endogenous IL-1Ra may suppress other occlusive vascular responses to injury, such as atherosclerosis and restenosis after angioplasty.

Objective: Atherosclerosis is considered to be a chronic inflammatory disease and many cytokines participate in the development of atherosclerosis. We focused on the role of interleukin-1beta (IL-1beta), one of the proinflammatory cytokines secreted by monocytes/macrophages, in the progression of atherosclerosis., Methods and Results: We generated mice lacking both apoE and IL-1beta. The sizes of atherosclerotic lesions at the aortic sinus in apoE-/-/IL-1beta-/-mice at 12 and 24 weeks of age showed a significant decrease of approximately 30% compared with apoE-/-/IL-1beta+/+ mice, and the percentage of the atherosclerotic area to total area of apoE-/-/IL-1beta-/- at 24 weeks of age also showed a significant decrease of about 30% compared with apoE-/-/IL-1beta+/+. The mRNA levels of vascular cell adhesion molecule (VCAM)-1 and monocyte chemotactic protein-1 in the apoE-/-/IL-1beta-/- aorta were significantly reduced compared with the apoE-/-/IL-1beta+/+. Furthermore, VCAM-1 was also reduced at the protein level in apoE-/-/IL-1beta-/- aorta compared with apoE-/-/IL-1beta+/+., Conclusions: The lack of IL-1beta decreases the severity of atherosclerosis in apoE deficient mice, possibly through increased expressions of VCAM-1 and monocyte chemotactic protein-1 in the aorta.

Background: As serum HIV-1 load correlates well with the prognosis of the disease, it is suggested that the viral load is one of the major determinants of the disease progression of AIDS. Accordingly, HIV-1 activation mechanisms were extensively studied in vitro, and involvement of cytokines including tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-6 and interferon (IFN)-gamma has been suggested in this process. However, so far the roles of these cytokines in the HIV-1 expression in vivo have not been well elucidated because of the lack of appropriate animal disease models., Objective: To elucidate the roles of cytokines in HIV-1 activation in vivo., Design and Methods: Transgenic mice carrying a defective HIV-1 genome were used as a model for HIV-1 carriers. In order to examine the possible involvement of cytokines in HIV-1 expression, TNF-alpha-, IL-1-, IL-6- and IFN-gamma-deficient HIV-1 transgenic mice, were produced and HIV-1 expression was analyzed after activation with bacterial lipopolysaccharides (LPS)., Results: HIV-1 expression in the transgenic mouse spleen was activated 10- to 20-fold by LPS, and the serum p24 Gag protein levels reached 400 pg/ml, which is nearly equal to the levels that occur in AIDS patients. However, this augmentation was suppressed by 60% in TNF-alpha-deficient mice and by 40% in IL-1alpha/beta-deficient mice. In contrast, no suppression was observed in either IL-6-, IFN-gamma-, IL-1alpha, or IL-1beta-deficient mice., Conclusions: Results suggest that TNF-alpha and IL-1 play important roles in HIV-1 gene activation and selective suppression of these cytokines could improve clinical prognosis and potentially slow progression of the disease.

Objective: To elucidate the tissue specificity of the expression of HIV-1 genes in an animal and its pathological effects on these tissues., Design and Methods: Transgenic mice carrying a defective HIV-1 genome were bred in order to overcome the host-range barrier of this virus., Results: mRNA specific to the transgene was detected in the eyes and the spleen, and, in smaller quantities, in the thymus and the brain. Interestingly, many of the transgenic mice developed cataracts at 3-6 months of age. Swelling and vacuolation of the lens fiber cells were marked, but the epithelial cells of the lens were less affected. HIV antigens were detected in the lens fiber cells and the retina by immunological staining. Accumulation of large amounts of p24 Gag antigen was demonstrated in the affected lens by immunoblot analysis, while negligible Env or other viral proteins was detected. Although accumulation of the Gag protein was also detected in the skin and the brain, no apparent abnormality was observed in these tissues., Conclusions: Preferential expression of the HIV genes in the eyes, skin, brain and lymphoid tissues was demonstrated. The accumulation of the Gag protein is suggested to have detrimental effects on lens fiber cells, causing cataracts.