CD8+ T-cells contribute to lesion stabilization in advanced atherosclerosis by limiting macrophage content and CD4+ T-cell responses

Human endarterectomy samples analyzed by flow cytometry showed a negative correlation between the percentage of CD8+ T-cells and macrophages, suggesting a possible protective role for these cells in lesion development. To further test this hypothesis, LDLr-/- mice were fed a Western-type diet (WTD) for 10 weeks to induce atherosclerosis, after which they received CD8α-depleting or isotype control antibody for six weeks. Depletion of CD8+ T-cells in advanced atherosclerosis resulted in less stable lesions, with significantly reduced collagen content in the trivalve area, increased macrophage content and increased necrotic core area compared to controls. Mechanistically, we observed that CD8 depletion specifically increased the fraction of Th1 CD4+ T-cells in the lesions. Treatment of WTD-fed LDLr-/- mice with a FasL-neutralizing antibody resulted in similar changes in macrophages and CD4+ T-cell skewing as CD8+ T-cell depletion. T lymphocytes play an important role in atherosclerosis development, but the role of the CD8+ T-cell remains debated, especially in the clinically relevant advanced stages of atherosclerosis development. Here, we set out to determine the role of CD8+ T-cells in advanced atherosclerosis. These findings demonstrate for the first time a local, protective role for CD8+ T-cells in advanced atherosclerosis, through limiting accumulation of Th1 cells and macrophages, identifying a novel regulatory mechanism for these cells in atherosclerosis. Methods and Results Aims ConclusionDrug Delivery Technolog

Adrenalectomy stimulates the formation of initial atherosclerotic lesions: Reversal by adrenal transplantation

Biopharmaceutic

The role of hepatocyte nuclear factor 4 alpha in regulating mouse hepatic anticoagulation and fibrinolysis gene transcript levels

Thrombosis and Hemostasi

Attenuated atherosclerosis upon IL-17R signaling disruption in LDLr deficient mice.

Contains fulltext : 80313.pdf (publisher's version ) (Closed access)Atherosclerosis is an inflammatory disease characterized by the influx of macrophages and T cells and IL-17 may connect innate and adaptive immune responses involved in atherogenesis. We investigated the role of IL-17 receptor signaling in atherosclerosis and transplanted LDLr deficient recipient mice with IL-17R deficient bone marrow. Induction of atherosclerosis by Western-type diet induced a 46% reduction in lesion size in the aortic root and the plaque composition revealed no significant changes in collagen content and neutrophil counts, but a reduction in mast cell number and an increase in macrophage number. In addition, we observed a decrease in anti-oxLDL antibodies of the IgG class upon IL-17R BMT, while introduction of IL-17R deficient bone marrow resulted in a reduced IL-6 production and an increased IL-10 production. In conclusion, signaling via the IL-17 receptor in bone marrow derived cells enhances the process of atherosclerosis

Impaired effector memory T-cell regulation facilitates graft versus host disease in CCR7-deficient bone marrow transplant chimeras

BACKGROUND: The development of graft versus host disease (GvHD) is one of the major challenges of bone marrow transplantations (BMTs). Although clinical symptoms of GvHD share many features with auto immune diseases, the underlying mechanisms remain unclear. Here, we examined the effects of hematopoietic CC-chemokine receptor (CCR)7 deficiency on the development of GvHD. METHODS: Lethally irradiated C57BL/6 mice were transplanted with bone marrow cells derived from wild-type or CCR7 C57BL/6 donor mice. RESULTS: Unlike littermate controls, CCR7 chimeras develop overt GvHD-like symptoms within 6 weeks after transplantation. Circulating CD4 and CD8 T-cell populations of CCR7 chimeras were enriched in effector memory T cells. CCR7 CD62L regulatory T-cell expansion, which typically occurs after BMT was markedly delayed in CCR7 chimeras. Furthermore, GvHD-like reactions did not occur after cotransplantation of wild-type and CCR7 bone marrow, showing that CCR7 is critically required for tolerance induction and prevention of GvHD. CONCLUSIONS: We are the first to demonstrate that lack of CCR7 results in delayed regulatory T-cell expansion. This results in insufficient control of effector memory T-cell expansion, which eventually leads to severe tissue damage. Conceivably, therapies aimed at boosting CD4 CD62L regulatory T-cell expansion after BMT could help to control GvHD

Hepatocyte-specific IKKbeta expression aggravates atherosclerosis development in APOE*3-Leiden mice

Item does not contain fulltextOBJECTIVE: The liver is the key organ involved in systemic inflammation, but the relation between hepatic inflammation and atherogenesis is poorly understood. Since nuclear factor-kappaB (NF-kappaB) is a central regulator of inflammatory processes, we hypothesized that chronically enhanced hepatic NF-kappaB activation, through hepatocyte-specific expression of IkappaB kinase-beta (IKKbeta) (LIKK), will aggravate atherosclerosis development in APOE*3-Leiden (E3L) mice. METHODS AND RESULTS: E3L.LIKK and E3L control littermates were fed a Western-type diet for 24 weeks. E3L.LIKK mice showed a 2.3-fold increased atherosclerotic lesion area and more advanced atherosclerosis in the aortic root with less segments without atherosclerotic lesions (11% vs. 42%), and more segments with mild (63% vs. 44%) and severe (26% vs. 14%) lesions. Expression of LIKK did not affect basal levels of inflammatory parameters, but plasma cytokine levels tended to be higher in E3L.LIKK mice after lipopolysaccharide (LPS) administration. E3L.LIKK mice showed transiently increased plasma cholesterol levels, confined to (V)LDL. This transient character resulted in a mild (+17%) increased cumulative plasma cholesterol exposure. CONCLUSION: We conclude that selective activation of NF-kappaB in hepatocytes considerably promotes atherosclerosis development which is (at least partly) explained by an increased sensitivity to proinflammatory triggers and transiently increased plasma cholesterol levels