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1.  Anhedonic behavior in cryptochrome 2-deficient mice is paralleled by altered diurnal patterns of amygdala gene expression 
Amino Acids  2015;47(7):1367-1377.
Mood disorders are frequently paralleled by disturbances in circadian rhythm-related physiological and behavioral states and genetic variants of clock genes have been associated with depression. Cryptochrome 2 (Cry2) is one of the core components of the molecular circadian machinery which has been linked to depression, both, in patients suffering from the disease and animal models of the disorder. Despite this circumstantial evidence, a direct causal relationship between Cry2 expression and depression has not been established. Here, a genetic mouse model of Cry2 deficiency (Cry2−/− mice) was employed to test the direct relevance of Cry2 for depression-like behavior. Augmented anhedonic behavior in the sucrose preference test, without alterations in behavioral despair, was observed in Cry2−/− mice. The novelty suppressed feeding paradigm revealed reduced hyponeophagia in Cry2−/− mice compared to wild-type littermates. Given the importance of the amygdala in the regulation of emotion and their relevance for the pathophysiology of depression, potential alterations in diurnal patterns of basolateral amygdala gene expression in Cry2−/− mice were investigated focusing on core clock genes and neurotrophic factor systems implicated in the pathophysiology of depression. Differential expression of the clock gene Bhlhe40 and the neurotrophic factor Vegfb were found in the beginning of the active (dark) phase in Cry2−/− compared to wild-type animals. Furthermore, amygdala tissue of Cry2−/− mice contained lower levels of Bdnf-III. Collectively, these results indicate that Cry2 exerts a critical role in the control of depression-related emotional states and modulates the chronobiological gene expression profile in the mouse amygdala.
Electronic supplementary material
The online version of this article (doi:10.1007/s00726-015-1968-3) contains supplementary material, which is available to authorized users.
PMCID: PMC4458264  PMID: 25820768
Cry2; Amygdala; Depression; Anhedonia; Clock gene; VEGF
2.  Semaphorin 3F forms an anti-angiogenic barrier in outer retina 
FEBS letters  2013;587(11):1650-1655.
Semaphorins are known modulators of axonal sprouting and angiogenesis. In the retina, we identified a distinct and almost exclusive expression of Semaphorin 3F in the outer layers. Interestingly, these outer retinal layers are physiologically avascular. Using functional in vitro models, we report potent anti-angiogenic effects of Semaphorin 3F on both retinal and choroidal vessels. In addition, human retinal pigment epithelium isolates from patients with pathologic neovascularization of the outer retina displayed reduced Semaphorin 3F expression in 10 out of 15 patients. Combined, these results elucidate a functional role for Semaphorin 3F in the outer retina where it acts as a vasorepulsive cue to maintain physiologic avascularity.
PMCID: PMC4016712  PMID: 23603393
Sema3F; Retina; AMD; RPE; Choroid
3.  Acetate Activation in Methanosaeta thermophila: Characterization of the Key Enzymes Pyrophosphatase and Acetyl-CoA Synthetase 
Archaea  2012;2012:315153.
The thermophilic methanogen Methanosaeta thermophila uses acetate as sole substrate for methanogenesis. It was proposed that the acetate activation reaction that is needed to feed acetate into the methanogenic pathway requires the hydrolysis of two ATP, whereas the acetate activation reaction in Methanosarcina sp. is known to require only one ATP. As these organisms live at the thermodynamic limit that sustains life, the acetate activation reaction in Mt. thermophila seems too costly and was thus reevaluated. It was found that of the putative acetate activation enzymes one gene encoding an AMP-forming acetyl-CoA synthetase was highly expressed. The corresponding enzyme was purified and characterized in detail. It catalyzed the ATP-dependent formation of acetyl-CoA, AMP, and pyrophosphate (PPi) and was only moderately inhibited by PPi. The breakdown of PPi was performed by a soluble pyrophosphatase. This enzyme was also purified and characterized. The pyrophosphatase hydrolyzed the major part of PPi (KM = 0.27 ± 0.05 mM) that was produced in the acetate activation reaction. Activity was not inhibited by nucleotides or PPi. However, it cannot be excluded that other PPi-dependent enzymes take advantage of the remaining PPi and contribute to the energy balance of the cell.
PMCID: PMC3426162  PMID: 22927778

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