AMP-Activated Protein Kinase alpha 2 in Neutrophils Regulates Vascular Repair via Hypoxia-Inducible Factor-1 alpha and a Network of Proteins Affecting Metabolism and Apoptosis

Rationale: The AMP-activated protein kinase (AMPK) is stimulated by hypoxia, and although the AMPK alpha 1 catalytic subunit has been implicated in angiogenesis, little is known about the role played by the AMPK alpha 2 subunit in vascular repair. Objective: To determine the role of the AMPK alpha 2 subunit in vascular repair. Methods and Results: Recovery of blood flow after femoral artery ligation was impaired (>80%) in AMPK alpha 2(-/-) versus wild-type mice, a phenotype reproduced in mice lacking AMPK alpha 2 in myeloid cells (AMPK alpha 2(Delta MC)). Three days after ligation, neutrophil infiltration into ischemic limbs of AMPK alpha 2(Delta MC) mice was lower than that in wild-type mice despite being higher after 24 hours. Neutrophil survival in ischemic tissue is required to attract monocytes that contribute to the angiogenic response. Indeed, apoptosis was increased in hypoxic neutrophils from AMPK alpha 2(Delta MC) mice, fewer monocytes were recruited, and gene array analysis revealed attenuated expression of proangiogenic proteins in ischemic AMPK alpha 2(Delta MC) hindlimbs. Many angiogenic growth factors are regulated by hypoxia-inducible factor, and hypoxia-inducible factor-1 alpha induction was attenuated in AMPK alpha 2-deficient cells and accompanied by its enhanced hydroxylation. Also, fewer proteins were regulated by hypoxia in neutrophils from AMPK alpha 2(Delta MC) mice. Mechanistically, isocitrate dehydrogenase expression and the production of alpha-ketoglutarate, which negatively regulate hypoxia-inducible factor-1 alpha stability, were attenuated in neutrophils from wild-type mice but remained elevated in cells from AMPK alpha 2(Delta MC) mice. Conclusions: AMPK alpha 2 regulates alpha-ketoglutarate generation, hypoxia-inducible factor-1 alpha stability, and neutrophil survival, which in turn determine further myeloid cell recruitment and repair potential. The activation of AMPK alpha 2 in neutrophils is a decisive event in the initiation of vascular repair after ischemia

Systemische Faktoren von Übergewicht/Adipositas bei Kindern im Vorschulalter

Einleitung: Die Ergebnisse mehrerer Metaanalysen legen nahe, dass auch Faktoren jenseits von Ernährung und körperlicher Aktivität einen signifikanten Einfluss auf die Entstehung von Übergewicht/Adipositas haben. In der vorliegenden Pilotstudie sollte sowohl eine Basis für eine groß angelegte Studie über systemische Risikofaktoren der Adipositasentstehung bei Kindern im Vorschulalter erarbeitet als auch nutritive, ethnische, soziale und bewegungsbezogene Faktoren, die mit Übergewicht/Adipositas assoziiert sind, hinsichtlich ihrer Wertigkeit verglichen werden. Methoden: Die Pilotstudie wurde in 6 Tageseinrichtungen für Kinder (N=199; Alter: 3-7 Jahre) durchgeführt. Die Datenerhebung umfasste eine Befragung der Kinder sowie den Einsatz von Fragebögen für ErzieherInnen und die Kindseltern. Mithilfe dieser Fragebögen wurden Informationen zum sozialen und ethnischen Familienhintergrund sowie über das Ernährungs- und Bewegungsverhalten der Kinder zu Hause und in den Einrichtungen gewonnen. Als Messparameter dienten Körpergröße, Körpergewicht und die Körperzusammensetzung mittels bioelektrischer Impedanzanalyse. Ergebnisse: 8% der Kinder waren übergewichtig (>90. Perzentile), 3% adipös (>97. Perzentile). 16% der Kinder waren untergewichtig (<10. Perzentile). Die am stärksten mit dem BMI bzw. der absoluten Fettmasse des Kindes korrelierten Größen waren der BMI der Mutter (p=0.001) sowie die Dauer des Fernsehkonsums (p=0.04) der Kinder. Das Bewegungsverhalten, der Migrationshintergrund, das Bildungsniveau der Eltern und das Ernährungsverhalten der Kinder waren in dieser Stichprobe nicht signifikant mit dem BMI der Kinder assoziiert bzw. korreliert. Schlussfolgerung: Ursachen für den höheren Anteil untergewichtiger im Vergleich zu übergewichtigen Kindern sollte vor dem Hintergrund der gegenwärtigen Adipositasdiskussion nicht vernachlässigt werden. Die hohe Assoziation nicht-ernährungsassoziierter Faktoren mit Übergewicht/Adipositas macht deutlich, dass nur ein systemischer Ansatz, der über die Faktoren der Ernährung und Bewegung hinausgeht, die Erarbeitung erfolgreicher Strategien bei der Bekämpfung von Adipositas ermöglicht

Endothelial AMP-Activated Kinase α1 Phosphorylates eNOS on Thr495 and Decreases Endothelial NO Formation

AMP-activated protein kinase (AMPK) is frequently reported to phosphorylate Ser1177 of the endothelial nitric-oxide synthase (eNOS), and therefore, is linked with a relaxing effect. However, previous studies failed to consistently demonstrate a major role for AMPK on eNOS-dependent relaxation. As AMPK also phosphorylates eNOS on the inhibitory Thr495 site, this study aimed to determine the role of AMPK&alpha;1 and &alpha;2 subunits in the regulation of NO-mediated vascular relaxation. Vascular reactivity to phenylephrine and acetylcholine was assessed in aortic and carotid artery segments from mice with global (AMPK&alpha;&minus;/&minus;) or endothelial-specific deletion (AMPK&alpha;&Delta;EC) of the AMPK&alpha; subunits. In control and AMPK&alpha;1-depleted human umbilical vein endothelial cells, eNOS phosphorylation on Ser1177 and Thr495 was assessed after AMPK activation with thiopental or ionomycin. Global deletion of the AMPK&alpha;1 or &alpha;2 subunit in mice did not affect vascular reactivity. The endothelial-specific deletion of the AMPK&alpha;1 subunit attenuated phenylephrine-mediated contraction in an eNOS- and endothelium-dependent manner. In in vitro studies, activation of AMPK did not alter the phosphorylation of eNOS on Ser1177, but increased its phosphorylation on Thr495. Depletion of AMPK&alpha;1 in cultured human endothelial cells decreased Thr495 phosphorylation without affecting Ser1177 phosphorylation. The results of this study indicate that AMPK&alpha;1 targets the inhibitory phosphorylation Thr495 site in the calmodulin-binding domain of eNOS to attenuate basal NO production and phenylephrine-induced vasoconstriction

Myeloid-specific deletion of the AMPK2 subunit alters monocyte protein expression and atherogenesis

The AMP-activated protein kinase (AMPK) is an energy sensing kinase that is activated by a drop in cellular ATP levels. Although several studies have addressed the role of the AMPKα1 subunit in monocytes and macrophages, little is known about the α2 subunit. The aim of this study was to assess the consequences of AMPKα2 deletion on protein expression in monocytes/macrophages, as well as on atherogenesis. A proteomics approach was applied to bone marrow derived monocytes from wild-type mice versus mice specifically lacking AMPKα2 in myeloid cells (AMPKα2∆MC mice). This revealed differentially expressed proteins, including methyltransferases. Indeed, AMPKα2 deletion in macrophages increased the ratio of S-adenosyl methionine to S-adenosyl homocysteine and increased global DNA cytosine methylation. Also, methylation of the vascular endothelial growth factor and matrix metalloproteinase-9 (MMP9) genes was increased in macrophages from AMPKα2∆MC mice, and correlated with their decreased expression. To link these findings with an in vivo phenotype, AMPKα2∆MC mice were crossed onto the ApoE-/- background and fed a western diet. ApoExAMPKα2∆MC mice developed smaller atherosclerotic plaques than their ApoExα2fl/fl littermates, that contained fewer macrophages and less MMP9 than plaques from ApoExα2fl/fl littermates. These results indicate that the AMPKα2 subunit in myeloid cells influences DNA methylation and thus protein expression and contributes to the development of atherosclerotic plaques

ConservePlants : an integrated approach to conservation of threatened plants for the 21st century

Even though plants represent an essential part of our lives offering exploitational, supporting and cultural services, we know very little about the biology of the rarest and most threatened plant species, and even less about their conservation status. Rapid changes in the environment and climate, today more pronounced than ever, affect their fitness and distribution causing rapid species declines, sometimes even before they had been discovered. Despite the high goals set by conservationists to protect native plants from further degradation and extinction, the initiatives for the conservation of threatened species in Europe are scattered and have not yielded the desired results. The main aim of this Action is to improve plant conservation in Europe through the establishment of a network of scientists and other stakeholders who deal with different aspects of plant conservation, from plant taxonomy, ecology, conservation genetics, conservation physiology and reproductive biology to protected area's managers, not forgetting social scientists, who are crucial when dealing with the general public.peer-reviewe