Fluoxetine up-regulates expression of cellular FLICE-inhibitory protein and inhibits LPS-induced apoptosis in hippocampus-derived neural stem cell

Fluoxetine is a widely used antidepressant compound which inhibits the reuptake of serotonin in the central nervous system. Recent studies have shown that fluoxetine can promote neurogenesis and improve the survival rate of neurons. However, whether fluoxetine modulates the proliferation or neuroprotection effects of neural stem cells (NSCs) needs to be elucidated. In this study, we demonstrated that 20 microM fluoxetine can increase the cell proliferation of NSCs derived from the hippocampus of adult rats by MTT test. The up-regulated expression of Bcl-2, Bcl-xL and the cellular FLICE-inhibitory protein (c-FLIP) in fluoxetine-treated NSCs was detected by real-time RT-PCR. Our results further showed that fluoxetine protects the lipopolysaccharide-induced apoptosis in NSCs, in part, by activating the expression of c-FLIP. Moreover, c-FLIP induction by fluoxetine requires the activation of the c-FLIP promoter region spanning nucleotides -414 to -133, including CREB and SP1 sites. This effect appeared to involve the phosphatidylinositol-3-kinase-dependent pathway. Furthermore, fluoxetine treatment significantly inhibited the induction of proinflammatory factor IL-1beta, IL-6, and TNF-alpha in the culture medium of LPS-treated NSCs (p<0.01). The results of high performance liquid chromatography coupled to electrochemical detection further confirmed that fluoxentine increased the functional production of serotonin in NSCs. Together, these data demonstrate the specific activation of c-FLIP by fluoxetine and indicate the novel role of fluoxetine for neuroprotection in the treatment of depression.     

Ubc9 acetylation modulates distinct SUMO target modification and hypoxia response

While numerous small ubiquitin‐like modifier (SUMO) conjugated substrates have been identified, very little is known about the cellular signalling mechanisms that differentially regulate substrate sumoylation. Here, we show that acetylation of SUMO E2 conjugase Ubc9 selectively downregulates the sumoylation of substrates with negatively charged amino acid‐dependent sumoylation motif (NDSM) consisting of clustered acidic residues located downstream from the core ψ‐K‐X‐E/D consensus motif, such as CBP and Elk‐1, but not substrates with core ψ‐K‐X‐E/D motif alone or SUMO‐interacting motif. Ubc9 is acetylated at residue K65 and K65 acetylation attenuates Ubc9 binding to NDSM substrates, causing a reduction in NDSM substrate sumoylation. Furthermore, Ubc9 K65 acetylation can be downregulated by hypoxia via SIRT1, and is correlated with hypoxia‐elicited modulation of sumoylation and target gene expression of CBP and Elk‐1 and cell survival. Our data suggest that Ubc9 acetylation/deacetylation serves as a dynamic switch for NDSM substrate sumoylation and we report a previously undescribed SIRT1/Ubc9 regulatory axis in the modulation of protein sumoylation and the hypoxia response.     

Indication of dynamic neurovascular coupling from inconsistency between EEG and fMRI indices across sleep–wake states

Sleep and Biological Rhythms - Neurovascular coupling (NVC), the transient regional hyperemia following the evoked neuronal responses, is the basis of blood oxygenation level-dependent techniques...     

Responses of mammalian metaphase chromosomes to endonuclease digestion

Digestion of fixed metaphase chromosomes by endonucleases (micrococcal nuclease and DNase II) under optimal digestion conditions followed by Giemsa staining produces sharp banding patterns identical to G-bands. In ³H-thymidine labeled, synchronized metaphase cells of the chinese hamster (CHO line), the band induction is accompanied by the removal of DNA. The single strand specific nuclease S1 and DNase I do not produce such banding patterns.     

Complementation between mutants of Phycomyces deficient with respect to carotenogenesis

Summary White and red mutants of Phycomyces, derived from two independent wild types (yellow) by mutagenesis using nitrosoguanidine, either in a single step (26 white, 5 red mutants), or in two steps (10 white mutants, from one of the red mutants) were studied with respect to complementation in heterokaryons. The tests clearly establish the involvement of three and only three genes, here named carA, carB, and carB. The carA and the carR mutants are white, the carA mutants do not accumulate phytoene, the carB mutants do. The carR mutants are red and accumulate lycopene. The two step mutants are either carA and carR, or carB and carR double mutants. A few of the white mutants obtained in a single mutagenization step are affected in carA and carR. They may be polar mutants in an operon or accidental double mutants.     

Immunochemical and functional studies of Actinomyces viscosus T14V type 1 fimbriae with monoclonal and polyclonal antibodies directed against the fimbrial subunit.

Each of five monoclonal antibodies (mAbs) prepared against the type 1 fimbriae of Actinomyces viscosus T14V reacted with a 54 kDa cloned protein previously identified as a fimbrial subunit. This purified protein completely inhibited the reaction of a specific anti-type-1-fimbria rabbit antibody with A. viscosus whole cells. Maximum values for the number of antibody molecules bound per bacterial cell ranged from 7 x 10(3) to 1.2 x 10(4) for the different 125I-labelled mAbs and was approximately 7 x 10(4) for 125I-labelled rabbit IgG or Fab against either type 1 fimbriae or the 54 kDa cloned protein. Although the different mAbs, either individually or as a mixture, failed to inhibit the type-1-fimbria-mediated adherence of A. viscosus T14V to saliva-treated hydroxyapatite, each rabbit antibody gave 50% inhibition of adherence when approximately 5 x 10(4) molecules of IgG were bound per cell. However, binding of each corresponding rabbit Fab had no significant effect on bacterial attachment unless much higher concentrations were used. These findings suggest that antibodies directed solely against the 54 kDa fimbrial subunit do not react with the putative receptor binding sites of A. viscosus T14V type 1 fimbriae. Instead, inhibition of attachment by the polyclonal antibodies may depend on an indirect effect of antibody binding that prevents the fimbria-receptor interaction.     

Obesity and Hepatic Steatosis Are Associated with Elevated Serum Amyloid Beta in Metabolically Stressed APPswe/PS1dE9 Mice

Diabesity-associated metabolic stresses modulate the development of Alzheimer’s disease (AD). For further insights into the underlying mechanisms, we examine whether the genetic background of APPswe/PS1dE9 at the prodromal stage of AD affects peripheral metabolism in the context of diabesity. We characterized APPswe/PS1dE9 transgenic mice treated with a combination of high-fat diet with streptozotocin (HFSTZ) in the early stage of AD. HFSTZ-treated APPswe/PS1dE9 transgenic mice exhibited worse metabolic stresses related to diabesity, while serum β-amyloid levels were elevated and hepatic steatosis became apparent. Importantly, two-way analysis of variance shows a significant interaction between HFSTZ and genetic background of AD, indicating that APPswe/PS1dE9 transgenic mice are more vulnerable to HFSTZ treatment. In addition, body weight gain, high hepatic triglyceride, and hyperglycemia were positively associated with serum β-amyloid, as validated by Pearson’s correlation analysis. Our data suggests that the interplay between genetic background of AD and HFSTZ-induced metabolic stresses contributes to the development of obesity and hepatic steatosis. Alleviating metabolic stresses including dysglycemia, obesity, and hepatic steatosis could be critical to prevent peripheral β-amyloid accumulation at the early stage of AD.     

HaplotypeCN: Copy Number Haplotype Inference with Hidden Markov Model and Localized Haplotype Clustering

Copy number variation (CNV) has been reported to be associated with disease and various cancers. Hence, identifying the accurate position and the type of CNV is currently a critical issue. There are many tools targeting on detecting CNV regions, constructing haplotype phases on CNV regions, or estimating the numerical copy numbers. However, none of them can do all of the three tasks at the same time. This paper presents a method based on Hidden Markov Model to detect parent specific copy number change on both chromosomes with signals from SNP arrays. A haplotype tree is constructed with dynamic branch merging to model the transition of the copy number status of the two alleles assessed at each SNP locus. The emission models are constructed for the genotypes formed with the two haplotypes. The proposed method can provide the segmentation points of the CNV regions as well as the haplotype phasing for the allelic status on each chromosome. The estimated copy numbers are provided as fractional numbers, which can accommodate the somatic mutation in cancer specimens that usually consist of heterogeneous cell populations. The algorithm is evaluated on simulated data and the previously published regions of CNV of the 270 HapMap individuals. The results were compared with five popular methods: PennCNV, genoCN, COKGEN, QuantiSNP and cnvHap. The application on oral cancer samples demonstrates how the proposed method can facilitate clinical association studies. The proposed algorithm exhibits comparable sensitivity of the CNV regions to the best algorithm in our genome-wide study and demonstrates the highest detection rate in SNP dense regions. In addition, we provide better haplotype phasing accuracy than similar approaches. The clinical association carried out with our fractional estimate of copy numbers in the cancer samples provides better detection power than that with integer copy number states.