38 research outputs found
Experimental test of magnetic photons
A "magnetic" photon hypothesis associated with magnetic monopoles is tested
experimentally. These photons are predicted to easily penetrate metal.
Experimentally the optical transmittance T of a metal foil was less than 2 x
10^-17. The hypothesis is not supported since it predicts T = 2 x 10^-12
Vitamin D receptor regulates intestinal proteins involved in cell proliferation, migration and stress response
BACKGROUND: Genome-wide association studies found low plasma levels of 25-hydroxyvitamin D and vitamin D receptor (VDR) polymorphisms associated with a higher prevalence of pathological changes in the intestine such as chronic inflammatory bowel diseases. METHODS: In this study, a proteomic approach was applied to understand the overall physiological importance of vitamin D in the small intestine, beyond its function in calcium and phosphate absorption. RESULTS: In total, 569 protein spots could be detected by two-dimensional-difference in-gel electrophoresis (2D-DIGE), and 82 proteins were considered as differentially regulated in the intestinal mucosa of VDR-deficient mice compared to that of wildtype (WT) mice. Fourteen clearly detectable proteins were identified by MS/MS and further analyzed by western blot and/or real-time RT-PCR. The differentially expressed proteins are functionally involved in cell proliferation, cell adhesion and cell migration, stress response and lipid transport. Mice lacking VDR revealed higher levels of intestinal proteins associated with proliferation and migration such as the 37/67Â kDa laminin receptor, collagen type VI (alpha 1 chain), keratin-19, tropomyosin-3, adseverin and higher levels of proteins involved in protein trafficking and stress response than WT mice. In contrast, proteins that are involved in transport of bile and fatty acids were down-regulated in small intestine of mice lacking VDR compared to WT mice. However, plasma and liver concentrations of cholesterol and triglycerides were not different between the two groups of mice. CONCLUSION: Collectively, these data imply VDR as an important factor for controlling cell proliferation, migration and stress response in the small intestine
Human Mesenchymal Stromal Cells Resolve Lipid Load in High Fat Diet-Induced Non-Alcoholic Steatohepatitis in Mice by Mitochondria Donation
Mesenchymal stromal cells (MSC) increasingly emerge as an option to ameliorate non-alcoholic steatohepatitis (NASH), a serious disease, which untreated may progress to liver cirrhosis and cancer. Before clinical translation, the mode of action of MSC needs to be established. Here, we established NASH in an immune-deficient mouse model by feeding a high fat diet. Human bone-marrow-derived MSC were delivered to the liver via intrasplenic transplantation. As verified by biochemical and image analyses, human mesenchymal stromal cells improved high-fat-diet-induced NASH in the mouse liver by decreasing hepatic lipid content and inflammation, as well as by restoring tissue homeostasis. MSC-mediated changes in gene expression indicated the switch from lipid storage to lipid utilization. It was obvious that host mouse hepatocytes harbored human mitochondria. Thus, it is feasible that resolution of NASH in mouse livers involved the donation of human mitochondria to the mouse hepatocytes. Therefore, human MSC might provide oxidative capacity for lipid breakdown followed by restoration of metabolic and tissue homeostasis
Mitochondrial Transfer by Human Mesenchymal Stromal Cells Ameliorates Hepatocyte Lipid Load in a Mouse Model of NASH
Mesenchymal stromal cell (MSC) transplantation ameliorated hepatic lipid load; tissue inflammation; and fibrosis in rodent animal models of non-alcoholic steatohepatitis (NASH) by as yet largely unknown mechanism(s). In a mouse model of NASH; we transplanted bone marrow-derived MSCs into the livers; which were analyzed one week thereafter. Combined metabolomic and proteomic data were applied to weighted gene correlation network analysis (WGCNA) and subsequent identification of key drivers. Livers were analyzed histologically and biochemically. The mechanisms of MSC action on hepatocyte lipid accumulation were studied in co-cultures of hepatocytes and MSCs by quantitative image analysis and immunocytochemistry. WGCNA and key driver analysis revealed that NASH caused the impairment of central carbon; amino acid; and lipid metabolism associated with mitochondrial and peroxisomal dysfunction; which was reversed by MSC treatment. MSC improved hepatic lipid metabolism and tissue homeostasis. In co-cultures of hepatocytes and MSCs; the decrease of lipid load was associated with the transfer of mitochondria from the MSCs to the hepatocytes via tunneling nanotubes (TNTs). Hence; MSCs may ameliorate lipid load and tissue perturbance by the donation of mitochondria to the hepatocytes. Thereby; they may provide oxidative capacity for lipid breakdown and thus promote recovery from NASH-induced metabolic impairment and tissue injury
Immune-Deficient Pfp/Rag2-/- Mice Featured Higher Adipose Tissue Mass and Liver Lipid Accumulation with Growing Age than Wildtype C57BL/6N Mice
Aging is a risk factor for adipose tissue dysfunction, which is associated with inflammatory
innate immune mechanisms. Since the adipose tissue/liver axis contributes to hepatosteatosis, we
sought to determine age-related adipose tissue dysfunction in the context of the activation of the
innate immune system fostering fatty liver phenotypes. Using wildtype and immune-deficient
mice, we compared visceral adipose tissue and liver mass as well as hepatic lipid storage in young
(ca. 14 weeks) and adult (ca. 30 weeks) mice. Adipocyte size was determined as an indicator of
adipocyte function and liver steatosis was quantified by hepatic lipid content. Further, lipid storage
was investigated under normal and steatosis-inducing culture conditions in isolated hepatocytes. The
physiological age-related increase in body weight was associated with a disproportionate increase in
adipose tissue mass in immune-deficient mice, which coincided with higher triglyceride storage in
the liver. Lipid storage was similar in isolated hepatocytes from wildtype and immune-deficient mice
under normal culture conditions but was significantly higher in immune-deficient than in wildtype
hepatocytes under steatosis-inducing culture conditions. Immune-deficient mice also displayed
increased inflammatory, adipogenic, and lipogenic markers in serum and adipose tissue. Thus, the
age-related increase in body weight coincided with an increase in adipose tissue mass and hepatic
steatosis. In association with a (pro-)inflammatory milieu, aging thus promotes hepatosteatosis,
especially in immune-deficient mice
Vitamin D Receptor Deficiency and Low Vitamin D Diet Stimulate Aortic Calcification and Osteogenic Key Factor Expression in Mice
Low levels of 25-hydroxy vitamin D (25(OH)D) are associated with cardiovascular diseases. Herein, we tested the hypothesis that vitamin D deficiency could be a causal factor in atherosclerotic vascular changes and vascular calcification. Aortic root sections of vitamin D receptor knockout (VDR−/−) mice that were stained for vascular calcification and immunostained for osteoblastic differentiation factors showed more calcified areas and a higher expression of the osteogenic key factors Msx2, Bmp2, and Runx2 than the wild-type mice (P<0.01). Data from LDL receptor knockout (LDLR−/−) mice that were fed western diet with either low (50 IU/kg), recommended (1,000 IU/kg), or high (10,000 IU/kg) amounts of vitamin D3 over 16 weeks revealed increasing plasma concentrations of 25(OH)D (P<0.001) with increasing intake of vitamin D, whereas levels of calcium and phosphorus in plasma and femur were not influenced by the dietary treatment. Mice treated with the low vitamin D diet had more calcified lesions and a higher expression of Msx2, Bmp2, and Runx2 in aortic roots than mice fed recommended or high amounts of vitamin D (P<0.001). Taken together, these findings indicate vitamin D deficiency as a risk factor for aortic valve and aortic vessel calcification and a stimulator of osteogenic key factor expression in these vascular areas
Untersuchungen zur Bedeutung des Vitamin D-Rezeptors für den Intestinaltrakt am murinen Versuchsmodell
Die genomischen Vitamin D-Wirkungen werden über den Vitamin D-Rezeptor (VDR) vermittelt, einem nukleären Transkriptionsfaktor. Über diesen steuert Vitamin D vor allem die intestinale Kalziumabsorption. Neuere Studien zeigten jedoch, dass Vitamin D auch Wirkungen besitzt, die nicht unmittelbar an die Kalziumregulation geknüpft sind. Daher bestand das Ziel der vorliegenden Arbeit darin, die Auswirkungen eines VDR-Defizits auf Mukosazellen des Darms zu untersuchen und dabei fokussiert die Effekte näher zu beschreiben, die klassischer Weise nicht mit der Kalziumhomöostase in Verbindung stehen. Ein genetisch bedingtes Fehlen des VDR im Vergleich zu Wildtyp-Mäusen führte zu einer Elongation der Mikrovilli des duodenalen Enterozyten, dass von einer vermehrten Bildung des Markerproteins Ezrin begleitet wurde. Desweiteren führte das VDR-Defizit zu Veränderungen in Zelladhäsionsmarkern wie dem Claudin-2 und dem Lamininrezeptor als auch von Proteinen die in die Zellstressantwort involviert sind.The vitamin D receptor (VDR), a nuclear transcription factor, mediates the genomic vitamin D effects. Through this mechanism, vitamin D controls the active intestinal calcium absorption and thus regulates the systemic calcium homeostasis and bone mineralization. Recently, new vitamin D functions have been discovered, that were not related to calcium regulation. Therefore, the aim of this work was to identify new non-calcium related vitamin D functions in the intestine by comparing a VDR-deficient mouse model with wildtype mice. The lack of VDR led to an increased microvilli length of duodenal enterocytes which was accompanied by an increased abundance of the essential microvilli-morphogenesis regulator ezrin. Furthermore, the VDR-deficit led to adaptations in proteins associated to cell adhesion, e.g. claudin-2 and the 67kDa-lamininreceptor as well as proteins related to the cellstress response system.vorgelegt von Hagen Kühn
Piecewise Modelling with State Subtypes
Abstract. Models addressing both structure and behaviour of a system are usually quite complex. Much of the complexity is caused by the necessity to distinguish between different cases, such as legal vs. illegal constellations of objects, typical vs. rare scenarios, and normal vs. exceptional flows of control. The result is an explosion of cases causing large and deeply nested case analyses. While those based on the kinds of objects involved can be tackled with standard dynamic dispatch, possibilities for differentiations based on the state of objects have not yet been considered for modelling. We show how the handling of class and state-induced distinctions can be unified under a common subtyping scheme, and how this scheme allows the simplification of models by splitting them into piecewise definitions. Using a running example, we demonstrate the potential of our approach and explain how it serves the consistent integration of static and dynamic specifications.
Immune-Deficient Pfp/Rag2-/- Mice Featured Higher Adipose Tissue Mass and Liver Lipid Accumulation with Growing Age than Wildtype C57BL/6N Mice
Aging is a risk factor for adipose tissue dysfunction, which is associated with inflammatory innate immune mechanisms. Since the adipose tissue/liver axis contributes to hepatosteatosis, we sought to determine age-related adipose tissue dysfunction in the context of the activation of the innate immune system fostering fatty liver phenotypes. Using wildtype and immune-deficient mice, we compared visceral adipose tissue and liver mass as well as hepatic lipid storage in young (ca. 14 weeks) and adult (ca. 30 weeks) mice. Adipocyte size was determined as an indicator of adipocyte function and liver steatosis was quantified by hepatic lipid content. Further, lipid storage was investigated under normal and steatosis-inducing culture conditions in isolated hepatocytes. The physiological age-related increase in body weight was associated with a disproportionate increase in adipose tissue mass in immune-deficient mice, which coincided with higher triglyceride storage in the liver. Lipid storage was similar in isolated hepatocytes from wildtype and immune-deficient mice under normal culture conditions but was significantly higher in immune-deficient than in wildtype hepatocytes under steatosis-inducing culture conditions. Immune-deficient mice also displayed increased inflammatory, adipogenic, and lipogenic markers in serum and adipose tissue. Thus, the age-related increase in body weight coincided with an increase in adipose tissue mass and hepatic steatosis. In association with a (pro-)inflammatory milieu, aging thus promotes hepatosteatosis, especially in immune-deficient mice
Immune-Deficient Pfp/Rag2-/- Mice Featured Higher Adipose Tissue Mass and Liver Lipid Accumulation with Growing Age than Wildtype C57BL/6N Mice
Aging is a risk factor for adipose tissue dysfunction, which is associated with inflammatory
innate immune mechanisms. Since the adipose tissue/liver axis contributes to hepatosteatosis, we
sought to determine age-related adipose tissue dysfunction in the context of the activation of the
innate immune system fostering fatty liver phenotypes. Using wildtype and immune-deficient
mice, we compared visceral adipose tissue and liver mass as well as hepatic lipid storage in young
(ca. 14 weeks) and adult (ca. 30 weeks) mice. Adipocyte size was determined as an indicator of
adipocyte function and liver steatosis was quantified by hepatic lipid content. Further, lipid storage
was investigated under normal and steatosis-inducing culture conditions in isolated hepatocytes. The
physiological age-related increase in body weight was associated with a disproportionate increase in
adipose tissue mass in immune-deficient mice, which coincided with higher triglyceride storage in
the liver. Lipid storage was similar in isolated hepatocytes from wildtype and immune-deficient mice
under normal culture conditions but was significantly higher in immune-deficient than in wildtype
hepatocytes under steatosis-inducing culture conditions. Immune-deficient mice also displayed
increased inflammatory, adipogenic, and lipogenic markers in serum and adipose tissue. Thus, the
age-related increase in body weight coincided with an increase in adipose tissue mass and hepatic
steatosis. In association with a (pro-)inflammatory milieu, aging thus promotes hepatosteatosis,
especially in immune-deficient mice