Atheroprotective role of the C5aR2 deficiency in apolipoprotein E deficient mice

In this work, the role of the C5a anaphylatoxin receptor C5aR2 in two atherosclerosis models was examined. Cardiovascular diseases (CVDs) are the main cause of death in the industrialized western world. Atherosclerosis is the underlying pathophysiological cause for CVDs. It causes myocardial infarction, angina pectoris, sudden cardiac death and stroke. Atherosclerosis is an inflammatory disease of the arterial vessel wall and evolves mainly at site of disturbed blood flow as seen at bifurcations. The complement system is a part of the innate immune system and acts as a first line of defense against intruding pathogens. It has been shown to be involved in the initiation and progression of atherogenesis in humans and mice. Its activation triggers the cleavage of C5 into C5a and C5b. C5a is an anaphylatoxin, which signals through its two receptors C5aR1 and C5aR2. It was shown for C5aR1 to be implicated in atherosclerosis where it facilitates atherogenesis. On the other hand, it was demonstrated that expression of the C5aR2 in human correlates with the stage of atherogenesis. Nevertheless, the contribution of C5aR2 in atherosclerosis remains mainly unexplored. Thus, the aim of this study was to identify the role of C5aR2 in two independent mouse models of chronic diet induced or acute injury induced atherosclerosis and the underlying processes regulated and effected by C5aR2. For both approaches a C5ar2-/-/Apoe-/- mouse model was used, with a hyperlipidemic Apoe-/- background.To investigate the underlying processes and mechanisms and the C5aR2 contribution to atherogenesis, gene expression of pro inflammatory cytokines and adhesion molecules, as well as the number of cells positive for pro inflammatory markers were analyzed In Both, the acute injury induced atherosclerosis and the chronic diet induced atherosclerosis, we found a reduced lesion size in C5ar2-/-/Apoe-/- compared to their corresponding Apoe-/- control mice. This reduction was accompanied by a more stable plaque phenotype. Analysis of the cellular composition and gene expression within the lesion also revealed a reduction in inflammatory cells and cytokines.Furthermore, in vitro analysis of bone marrow derived macrophages indicate that in C5ar2-/-/Apoe-/- macrophages a shift in the polarization towards an anti inflammatory M2 phenotype occurs, which results in a reduction in pro inflammatory cytokine and adhesion molecule expression. On the other hand, systemic analysis demonstrated an increase in blood triglyceride and a reduction of cholesterol levels. Additionally, in the liver of C5ar2-/-/Apoe-/- mice elevated expression levels of pro inflammatory cytokines was found which might be a stress response of the liver to the elevated systemic triglyceride levels.Finally, to investigate the cooperative effect of blocking both C5a receptors, C5ar2-/-/Apoe-/- mice which underwent endothelial denudation additionally were implanted an osmotic mini pump equipped with a C5aR1 blocking inhibitor (C5aR1 A). Analysis of the carotid arteries revealed a further reduction in lesion size in C5aR1 A treated C5ar2-/-/Apoe-/- mice. This also manifests in a reduced macrophage number and pro inflammatory cytokine and adhesion molecule expression, whereas SMC numbers stay unchanged. Taken together, these data indicate that manipulating both receptors for C5a could provide an additional beneficial effect in handling atherosclerosis and restenosis. In summary, the shown data demonstrate that the C5aR2 is a functional receptor acting in a pro atherogenic manner on the progression and initiation of atherosclerosis. C5R2 induces pro inflammatory cytokine expression and inflammatory cell recruitment, which may be the cause how C5aR2 is mediating the atherogenic effect. This makes C5aR2 a suitable candidate for future drug targeting in order to handle atherosclerosis and restenosis. Nevertheless, further experiments are needed to clarify the exact mechanism of how C5aR2 is mediating the pro atherogenic effect

Perinatal Nutritional and Metabolic Pathways: Early Origins of Chronic Lung Diseases

Lung development is not completed at birth, but expands beyond infancy, rendering the lung highly susceptible to injury. Exposure to various influences during a critical window of organ growth can interfere with the finely-tuned process of development and induce pathological processes with aberrant alveolarization and long-term structural and functional sequelae. This concept of developmental origins of chronic disease has been coined as perinatal programming. Some adverse perinatal factors, including prematurity along with respiratory support, are well-recognized to induce bronchopulmonary dysplasia (BPD), a neonatal chronic lung disease that is characterized by arrest of alveolar and microvascular formation as well as lung matrix remodeling. While the pathogenesis of various experimental models focus on oxygen toxicity, mechanical ventilation and inflammation, the role of nutrition before and after birth remain poorly investigated. There is accumulating clinical and experimental evidence that intrauterine growth restriction (IUGR) as a consequence of limited nutritive supply due to placental insufficiency or maternal malnutrition is a major risk factor for BPD and impaired lung function later in life. In contrast, a surplus of nutrition with perinatal maternal obesity, accelerated postnatal weight gain and early childhood obesity is associated with wheezing and adverse clinical course of chronic lung diseases, such as asthma. While the link between perinatal nutrition and lung health has been described, the underlying mechanisms remain poorly understood. There are initial data showing that inflammatory and nutrient sensing processes are involved in programming of alveolarization, pulmonary angiogenesis, and composition of extracellular matrix. Here, we provide a comprehensive overview of the current knowledge regarding the impact of perinatal metabolism and nutrition on the lung and beyond the cardiopulmonary system as well as possible mechanisms determining the individual susceptibility to CLD early in life. We aim to emphasize the importance of unraveling the mechanisms of perinatal metabolic programming to develop novel preventive and therapeutic avenues

Differential Role for Activating Fc gamma RIII in Neointima Formation After Arterial Injury and Diet-Induced Chronic Atherosclerosis inApolipoprotein E-Deficient Mice

Atherogenesis and arterial remodeling following mechanical injury are driven by inflammation and mononuclear cell infiltration. The binding of immune complexes (ICs) to immunoglobulin (Ig)-Fc gamma receptors (Fc gamma Rs) on most innate and adaptive immune cells induces a variety of inflammatory responses that promote atherogenesis. Here, we studied the role of Fc gamma RIII in neointima formation after arterial injury in atherosclerosis-prone mice and compared the outcome and mechanism to that of Fc gamma RIII in diet-induced chronic atherosclerosis.Fc gamma rIII(-/-)/Apoe(-/-)and controlApoe(-/-)mice were subjected to wire-induced endothelial denudation of the carotid artery while on high-fat diet (HFD).Fc gamma rIIIdeficiency mitigated neointimal plaque formation and lesional macrophage accumulation, and enhanced neointimal vascular smooth muscle cell (VSMC) numbers. This went along with a reduced expression of tumor necrosis factor-alpha (TNF-alpha), monocyte chemoattractant protein-1 (MCP-1/CCL2), and vascular cell adhesion molecule-1 (VCAM-1) in the neointimal lesions. Interestingly, in a chronic model of diet-induced atherosclerosis, we unraveled a dichotomic role of Fc gamma RIII in an early versus advanced stage of the disease. WhileFc gamma rIIIdeficiency conferred atheroprotection in the early stage, it promoted atherosclerosis in advanced stages. To this end,Fc gamma rIIIdeficiency attenuated pro-inflammatory responses in early atherosclerosis but promoted these events in advanced stages. Analysis of the mechanism(s) underlying the athero-promoting effect ofFc gamma rIIIdeficiency in late-stage atherosclerosis revealed increased serum levels of anti-oxidized-LDL immunoglobulins IgG2c and IgG2b. This was paralleled by enhanced lesional accumulation of IgGs without affecting levels of complement-activated products C5a or C5ar1, Fc gamma RII, and Fc gamma RIV. Moreover,Fc gamma rIII-deficient macrophages expressed moreFc gamma rII,Tnf-alpha, andIl-1 beta mRNA when exposed to IgG1 or oxLDL-IgG1 ICsin vitro, and peripheral CD4+ and CD8+ T-cell levels were altered. Collectively, our data suggest that deficiency of activatingFc gamma RIIIlimits neointima formation after arterial injury in atherosclerosis-prone mice as well as early stage chronic atherosclerosis, but augments late-stage atherosclerosis suggesting a dual role of Fc gamma RIII in atherogenic inflammation

Kompressionskräfte am hinteren Beckenring bei instabilen B/C-Frakturen: Neues modulares Kompressionsmodul zur verbesserten Applikation des supraazetabulären Beckenfixateurs

Atherogenic processes and vascular remodelling after arterial injury are controlled and driven by a plethora of factors amongst which the activation of the complement system is pivotal. Recently, we reported a clear correlation between high expressions of the second receptor for complement anaphylatoxin C5a, the C5a receptor-like 2 (C5L2, C5aR2), with high pro-inflammatory cytokine expression in advanced human atherosclerotic plaques. This prompted us to speculate that C5aR2 might have a functional role in atherosclerosis. We, therefore, investigated the role of C5aR2 in atherosclerosis and vascular remodelling. Here, we demonstrate that C5ar2 deletion, in atherosclerosis-prone mice, attenuates atherosclerotic as well as neointimal plaque formation, reduces macrophages and CD3+ T cells and induces features of plaque stability, as analysed by histomorphometry and quantitative immunohistochemistry. As a possible underlying mechanism, C5ar2-deficient plaques showed significantly reduced expression of C5a receptor (C5ar1), Tnf-? as well as Vcam-1, as determined by qPCR and quantitative immunohistochemistry. In addition, in vitro mechanistic studies revealed a reduction of these pro-inflammatory and pro-atherosclerotic mediators in C5ar2-deficient macrophages. Finally, blocking C5ar1 with antagonist JPE1375, in C5ar2(-/-)/Apoe(-/-) mice, led to a further reduction in neointimal plaque formation with reduced inflammation. In conclusion, C5ar2 deficiency attenuates atherosclerosis and neointimal plaque formation after arterial injury. This identifies C5aR2 as a promising target to reduce atherosclerosis and restenosis after vascular interventions

Maternal high-fat diet induces long-term obesity with sex-dependent metabolic programming of adipocyte differentiation, hypertrophy and dysfunction in the offspring

Maternal obesity determines obesity and metabolic diseases in the offspring. The white adipose tissue (WAT) orchestrates metabolic pathways, and its dysfunction contributes to metabolic disorders in a sex-dependent manner. Here, we tested if sex differences influence the molecular mechanisms of metabolic programming of WAT in offspring of obese dams. To this end, maternal obesity was induced with high-fat diet (HFD) and the offspring were studied at an early phase [postnatal day 21 (P21)], a late phase (P70) and finally P120. In the early phase we found a sex-independent increase in WAT in offspring of obese dams using magnetic resonance imaging (MRI), which was more pronounced in females than males. While the adipocyte size increased in both sexes, the distribution of WAT differed in males and females. As mechanistic hints, we identified an inflammatory response in females and a senescence-associated reduction in the preadipocyte factor DLK in males. In the late phase, the obese body composition persisted in both sexes, with a partial reversal in females. Moreover, female offspring recovered completely from both the adipocyte hypertrophy and the inflammatory response. These findings were linked to a dysregulation of lipolytic, adipogenic and sternness-related markers as well as AMPK alpha and Akt signaling. Finally, the sex-dependent metabolic programming persisted with sex-specific differences in adipocyte size until P120. In conclusion, we do not only provide new insights into the molecular mechanisms of sex-dependent metabolic programming of WAT dysfunction, but also highlight the sex-dependent development of low- and high-grade pathogenic obesity

Maternal high-fat diet induces long-term obesity with sex-dependent metabolic programming of adipocyte differentiation, hypertrophy and dysfunction in he offspring

Maternal obesity determines obesity and metabolic diseases in the offspring. The white adipose tissue (WAT) orchestrates metabolic pathways, and its dysfunction contributes to metabolic disorders in a sex-dependent manner. Here, we tested if sex differences influence the molecular mechanisms of metabolic programming of WAT in offspring of obese dams. To this end, maternal obesity was induced with high-fat diet (HFD) and the offspring were studied at an early phase [postnatal day 21 (P21)], a late phase (P70) and finally P120. In the early phase we found a sex-independent increase in WAT in offspring of obese dams using magnetic resonance imaging (MRI), which was more pronounced in females than males. While the adipocyte size increased in both sexes, the distribution of WAT differed in males and females. As mechanistic hints, we identified an inflammatory response in females and a senescence-associated reduction in the preadipocyte factor DLK in males. In the late phase, the obese body composition persisted in both sexes, with a partial reversal in females. Moreover, female offspring recovered completely from both the adipocyte hypertrophy and the inflammatory response. These findings were linked to a dysregulation of lipolytic, adipogenic and sternness-related markers as well as AMPK alpha and Akt signaling. Finally, the sex-dependent metabolic programming persisted with sex-specific differences in adipocyte size until P120. In conclusion, we do not only provide new insights into the molecular mechanisms of sex-dependent metabolic programming of WAT dysfunction, but also highlight the sex-dependent development of low- and high-grade pathogenic obesity

Perinatal Obesity Sensitizes for Premature Kidney Aging Signaling

Chronic Kidney Disease (CKD), a global health burden, is strongly associated with age-related renal function decline, hypertension, and diabetes, which are all frequent consequences of obesity. Despite extensive studies, the mechanisms determining susceptibility to CKD remain insufficiently understood. Clinical evidence together with prior studies from our group showed that perinatal metabolic disorders after intrauterine growth restriction or maternal obesity adversely affect kidney structure and function throughout life. Since obesity and aging processes converge in similar pathways we tested if perinatal obesity caused by high-fat diet (HFD)-fed dams sensitizes aging-associated mechanisms in kidneys of newborn mice. The results showed a marked increase of γH2AX-positive cells with elevated 8-Oxo-dG (RNA/DNA damage), both indicative of DNA damage response and oxidative stress. Using unbiased comprehensive transcriptomics we identified compartment-specific differentially-regulated signaling pathways in kidneys after perinatal obesity. Comparison of these data to transcriptomic data of naturally aged kidneys and prematurely aged kidneys of genetic modified mice with a hypomorphic allele of Ercc1, revealed similar signatures, e.g., inflammatory signaling. In a biochemical approach we validated pathways of inflammaging in the kidneys after perinatal obesity. Collectively, our initial findings demonstrate premature aging-associated processes as a consequence of perinatal obesity that could determine the susceptibility for CKD early in life

Perinatal Obesity Induces Hepatic Growth Restriction with Increased DNA Damage Response, Senescence, and Dysregulated Igf-1-Akt-Foxo1 Signaling in Male Offspring of Obese Mice

Maternal obesity predisposes for hepato-metabolic disorders early in life. However, the underlying mechanisms causing early onset dysfunction of the liver and metabolism remain elusive. Since obesity is associated with subacute chronic inflammation and accelerated aging, we test the hypothesis whether maternal obesity induces aging processes in the developing liver and determines thereby hepatic growth. To this end, maternal obesity was induced with high-fat diet (HFD) in C57BL/6N mice and male offspring were studied at the end of the lactation [postnatal day 21 (P21)]. Maternal obesity induced an obese body composition with metabolic inflammation and a marked hepatic growth restriction in the male offspring at P21. Proteomic and molecular analyses revealed three interrelated mechanisms that might account for the impaired hepatic growth pattern, indicating prematurely induced aging processes: (1) Increased DNA damage response (γH2AX), (2) significant upregulation of hepatocellular senescence markers (Cdnk1a, Cdkn2a); and (3) inhibition of hepatic insulin/insulin-like growth factor (IGF)-1-AKT-p38-FoxO1 signaling with an insufficient proliferative growth response. In conclusion, our murine data demonstrate that perinatal obesity induces an obese body composition in male offspring with hepatic growth restriction through a possible premature hepatic aging that is indicated by a pathologic sequence of inflammation, DNA damage, senescence, and signs of a possibly insufficient regenerative capacity