Disruption of hedgehog signalling in ApoE - /- mice reduces plasma lipid levels, but increases atherosclerosis due to enhanced lipid uptake by macrophages.
ABSTRACT Embryonic pathways are often re-expressed in adult pathology. Here we investigated the role of the morphogen hedgehog (hh), which we found to be re-expressed in atherosclerotic plaques. Male ApoE - /- mice were treated for 12 weeks with an anti-hh antibody (5E1) or a control IgG (1E6) starting at the age of 6 or 18 weeks. Inhibition of hh signalling induced a significant increase in total plaque area in the aortic arch, a result of an increase (54% and 36%, respectively) in the area of advanced plaques (atheromata). In mice treated with anti-hh, plaques contained large (18-35% > ctrl), lipid-filled, sometimes multinucleated macrophage foam cells. Plasma cholesterol levels decreased after anti-hh treatment. In bone marrow-derived macrophages, foam cell formation was enhanced after inhibition of hh signalling. Anti-hh treatment caused a 54-75% increase in early oxLDL uptake (10-240 min), which was scavenger receptor-mediated. After 3-24 h of oxLDL incubation, intense Oil red O staining as well as increased amounts of cholesterol esters were present in these macrophages after anti-hh treatment. Activation of the HH-signalling cascade by recombinant Shh induced a decrease in oxLDL uptake. Here we show that the hh-signalling pathway is one of the morphogenic pathways that regulate plasma lipid levels and atherosclerosis development and progression.
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ABSTRACT: In this paper, an efficient l1-regularized reconstruction method named the primal-dual interior-point (PDIP) method is presented for three-dimensional bioluminescence tomography (BLT) based on the adaptive finite element framework. Taking into account the sparse characteristic of the bioluminescent source, the BLT inverse problem is considered to be a linear programming problem and is represented by its primal and dual form. The source localization and quantification are obtained by solving the primal-dual Newton equation system. The comparisons between PDIP and the classical conjugate gradient least square (CGLS) algorithm are implemented to validate our method. Results from numerical simulation and an in vivo mouse experiment demonstrate the credibility and the potential of the proposed method in practical BLT reconstruction.Optics Communications 01/2011; 284(24):5871-5876. · 1.44 Impact Factor
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ABSTRACT: Metabolic Zonation, i.e. the heterogeneous distribution of different metabolic pathways in different zones of the lobules, forms the basis of proper function of the liver in metabolic homeostasis and its regulation. According to recent results, Metabolic Zonation is controlled by the Wnt/β-catenin signalling pathway. Here, we hypothesize that hedgehog signalling via Indian hedgehog ligands plays an equal share in this control although, up to now, hedgehog signalling is considered not to be active in healthy adult hepatocytes. We provide broad evidence taken mainly by analogy from other mature organs that hedgehog signalling in adult hepatocytes may particularly control liver lipid and cholesterol metabolism as well as certain aspects of hormone biosynthesis. Like Wnt/β-catenin signalling, it seems to act on a very low level forming a porto-central gradient in the lobules opposite to that of Wnt/β-catenin signalling with which it is interacting by mutual inhibition. Consequently, modulation of hegdehog signalling by endogenous and exogenous agents may considerably impact on liver lipid metabolism and beyond. If functioning improperly, it may possibly contribute to diseases like non-alcoholic fatty liver disease (NAFLD) and other diseases such as lipodystrophy.Medical Hypotheses 02/2013; 80:589-594. · 1.18 Impact Factor
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ABSTRACT: Macrophage-derived foam cell formation elicited by oxidized low-density lipoprotein (oxLDL) is the hallmark of early atherogenesis. Detection of foam cell formation is conventionally practiced by Oil Red O (ORO) staining of lipid-laden macrophages. Other methods include 1,1'-dioctadecyl-3,3,3'3'-tetra-methylindocyanide percholorate (DiI)-labeled oxLDL (DiI-oxLDL) uptake and Nile Red staining. The purpose of the present study is to report an optimized method for assessing foam cell formation in cultured macrophages by ORO staining and DiI-oxLDL uptake. After incubation with oxLDL (50 μg/ml) for 24 h, the macrophages were fixed, stained with ORO for just 1 min, pronounced lipid droplets were clearly observed in more than 90% of the macrophages. To test the in vivo applicability of this method, lesions (or foam cells) of cryosections of aortic sinus or primary mouse peritoneal macrophages from ApoE deficient mice fed a high cholesterol diet were successfully stained. In another set of experiments, treatment of macrophages with DiI-oxLDL (10 μg/ml) for 4 h resulted in significant increase in oxLDL uptake in macrophages as demonstrated by confocol microscopy and flow cytometry. We conclude that the optimized ORO staining and fluorescent labeled oxLDL uptake techniques are very useful for assessing intracellular lipid accumulation in macrophages that are simpler and more rapid than currently used methods.Cytotechnology 11/2010; 62(5):473-81. · 1.32 Impact Factor