Chemical Induction of Trophoblast Hypoxia by Cobalt Chloride Leads to Increased Expression of DDIT3
Choriocarcinoma cells BeWo b30 are used to model human placental trophoblast hypoxia using cobalt (II) chloride and hydroxyquinoline derivative (HD) as chemical inducers of hypoxia-inducible factor (HIF). In this study, it was shown that both substances activate the hypoxic pathway and the epithelial–mesenchymal transition and inhibit the pathways of cell proliferation. However, CoCl2 caused activation of the apoptosis pathway, increased the activity of effector caspases 3 and 7, and increased the expression of the unfolded protein response target DDIT3. The mTORC1 pathway was activated upon exposition to CoCl2, while HD suppressed this pathway, as it happens during real trophoblast hypoxia. Thus, effect of CoCl2 on BeWo cells can be a model of severe hypoxia with activation of apoptosis, while HD mimics moderate hypoxia.
Hypoxia of trophoblast cells is an important regulating factor in the process of normal placenta development. However, the effect of hypoxia on the placenta in a number of pathological conditions, such as preeclampsia, leads to impaired cellular functions. A oxyquinoline derivative is capable of inhibiting HIF-prolyl hydroxylases, thereby stabilizing the transcription complex of HIF-1 and activating the cell response to hypoxia. BeWo b30 human choriocarcinoma cells are used to model trophoblast, which forms the basis for placenta barrier. Oxyquinoline effect leads both to an increased expression of a number of the genes that form the core response to hypoxia, and upregulated expression of NOS3, PDK1, and BNIP3 genes and downregulated expression of the PPARGC1B gene. This indicates the activation of mechanisms of metabolic cell reprogramming aimed at reducing oxygen consumption by reducing the number of mitochondria and switching from aerobic glucose metabolism to anaerobic. Possible applications of the obtained results is under discussion.
An in vitro placental barrier model based on human choriocarcinoma BeWo b30 cell line was considered as a method of preclinical study of the transport and toxicity of antitumor agents and other organic compounds. Low permeabilities were found for 5-fluorouracil as an example of hydrophilic compound and for doxorubicin as an example of a lipophilic compound with a high degree of binding to proteins and DNA and a high permeability was found for cyclophosphamide as an example of lipophilic compound with a low degree of binding to proteins. Using impedance spectrometry and cell viability assessment via reduction of resazurin to resorufin, a pronounced cytotoxic effect of doxorubicin and good tolerance of 5-fluorouracil and cyclophosphamide by the cells were shown for drug concentrations equal to the maximum concentrations in the patients’ blood during the treatment of breast cancer.
One of the key advances in genome assembly that has led to a significant improvement in contig lengths has been improved algorithms for utilization of paired reads (mate-pairs). While in most assemblers, mate-pair information is used in a post-processing step, the recently proposed Paired de Bruijn Graph (PDBG) approach incorporates the mate-pair information directly in the assembly graph structure. However, the PDBG approach faces difficulties when the variation in the insert sizes is high. To address this problem, we first transform mate-pairs into edge-pair histograms that allow one to better estimate the distance between edges in the assembly graph that represent regions linked by multiple mate-pairs. Further, we combine the ideas of mate-pair transformation and PDBGs to construct new data structures for genome assembly: pathsets and pathset graphs.
Papers about natural protection territories
Many environmental stimuli present a quasi-rhythmic structure at different timescales that the brain needs to decompose and integrate. Cortical oscillations have been proposed as instruments of sensory de-multiplexing, i.e., the parallel processing of different frequency streams in sensory signals. Yet their causal role in such a process has never been demonstrated. Here, we used a neural microcircuit model to address whether coupled theta–gamma oscillations, as observed in human auditory cortex, could underpin the multiscale sensory analysis of speech. We show that, in continuous speech, theta oscillations can flexibly track the syllabic rhythm and temporally organize the phoneme-level response of gamma neurons into a code that enables syllable identification. The tracking of slow speech fluctuations by theta oscillations, and its coupling to gamma-spiking activity both appeared as critical features for accurate speech encoding. These results demonstrate that cortical oscillations can be a key instrument of speech de-multiplexing, parsing, and encoding.
Neuronal nicotinic acetylcholine receptors (NNRs) of the α7 subtype have been shown to contribute to the release of dopamine in the nucleus accumbens. The site of action and the underlying mechanism, however, are unclear. Here we applied a circuit modeling approach, supported by electrochemical in vivo recordings, to clarify this issue. Modeling revealed two potential mechanisms for the drop in accumbal dopamine efflux evoked by the selective α7 partial agonist TC-7020. TC-7020 could desensitize α7 NNRs located predominantly on dopamine neurons or glutamatergic afferents to them or, alternatively, activate α7 NNRs located on the glutamatergic afferents to GABAergic interneurons in the ventral tegmental area. Only the model based on desensitization, however, was able to explain the neutralizing effect of coapplied PNU-120596, a positive allosteric modulator. According to our results, the most likely sites of action are the preterminal α7 NNRs controlling glutamate release from cortical afferents to the nucleus accumbens. These findings offer a rationale for the further investigation of α7 NNR agonists as therapy for diseases associated with enhanced mesolimbic dopaminergic tone, such as schizophrenia and addiction