Hepatitis B virus X protein and the estrogen receptor variant lacking exon 5 inhibit estrogen receptor signaling in hepatoma cells

Hepatitis B virus (HBV) X protein (HBx) is considered to play a role in the development of hepatocellular carcinoma (HCC) during HBV infection. HCC was shown to be more prevalent in men than in women. Estrogen, which exerts its biological function through estrogen receptor (ER), can inhibit HBV replication. ERΔ5, an ERα variant lacking exon 5, was found to be preferentially expressed in patients with HCC compared with patients with normal livers. Here, we report the biological role of ERΔ5 and a novel link between HBx and ERα signaling in hepatoma cells. ERΔ5 interacts with ERα in vitro and in vivo and functions as a dominant negative receptor. Both ERα and ERΔ5 associate with HBx. HBx decreases ERα-dependent transcriptional activity, and HBx and ERΔ5 have additive effect on suppression of ERα transactivation. The HBx deletion mutant that lacks the ERα-binding site abolishes the HBx repression of ERα. HBx, ERα and histone deacetylase 1 (HDAC1) form a ternary complex. Trichostatin A, a specific inhibitor of HDAC enzyme, can restore the transcriptional activity of ERα inhibited by HBx. Our data suggest that HBx and ERΔ5 may play a negative role in ERα signaling and that ERα agonists may be developed for HCC therapy

Suppression of Estrogen Receptor Transcriptional Activity by Connective Tissue Growth Factor

Secreted growth factors have been shown to stimulate the transcriptional activity of estrogen receptors (ER) that are responsible for many biological processes. However, whether these growth factors physically interact with ER remains unclear. Here, we show for the first time that connective tissue growth factor (CTGF) physically and functionally associates with ER. CTGF interacted with ER both in vitro and in vivo. CTGF interacted with ER DNA-binding domain. ER interaction region in CTGF was mapped to the thrombospondin type I repeat, a cell attachment motif. Overexpression of CTGF inhibited ER transcriptional activity as well as the expression of estrogen-responsive genes, including pS2 and cathepsin D. Reduction of endogenous CTGF with CTGF small interfering RNA enhanced ER transcriptional activity. The interaction between CTGF and ER is required for the repression of estrogen-responsive transcription by CTGF. Moreover, CTGF reduced ER protein expression, whereas the CTGF mutant that did not repress ER transcriptional activity also did not alter ER protein levels. The results suggested the transcriptional regulation of estrogen signaling through interaction between CTGF and ER, and thus may provide a novel mechanism by which cross-talk between secreted growth factor and ER signaling pathways occurs

Investigation of Free Fatty Acid Associated Recombinant Membrane Receptor Protein Expression in HEK293 Cells Using Raman Spectroscopy, Calcium Imaging, and Atomic Force Microscopy

G-protein-coupled receptor 120 (GPR120) is a previously orphaned G-protein-coupled receptor that apparently functions as a sensor for dietary fat in the gustatory and digestive systems. In this study, a cDNA sequence encoding a doxycycline (Dox)-inducible mature peptide of GPR120 was inserted into an expression vector and transfected in HEK293 cells. We measured Raman spectra of single HEK293 cells as well as GPR120-expressing HEK293–GPR120 cells at a 48 h period following the additions of Dox at several concentrations. We found that the spectral intensity of HEK293–GPR120 cells is dependent upon the dose of Dox, which correlates with the accumulation of GPR120 protein in the cells. However, the amount of the fatty acid activated changes in intracellular calcium (Ca²⁺) as measured by ratiometric calcium imaging was not correlated with Dox concentration. Principal components analysis (PCA) of Raman spectra reveals that the spectra from different treatments of HEK293–GPR120 cells form distinct, completely separated clusters with the receiver operating characteristic (ROC) area of 1, while those spectra for the HEK293 cells form small overlap clusters with the ROC area of 0.836. It was also found that expression of GPR120 altered the physiochemical and biomechanical properties of the parental cell membrane surface, which was quantitated by atomic force microscopy (AFM). These findings demonstrate that the combination of Raman spectroscopy, calcium imaging, and AFM may provide new tools in noninvasive and quantitative monitoring of membrane receptor expression induced alterations in the biophysical and signaling properties of single living cells

Incidence of a brain structural abnormities (CT, NMR) in patients with affective disorder

Currently we are experiencing a boom imaging methods. We are constantly improving their accessibility, their distinctive abilities and the possibility of using both in research and in clinical practice. They penetrate well into psychiatry, where he tries as well as in other fields to shed light etiology of diseases contribute to their diagnosis and treatment. The cost of are large, the cost of execution of each test is different, can Thus burden on public budgets in different ways, so it is necessary to were determined and the proper indications. What is the significance of these methods in determine the incidence of brain structural abnormalities in patients with affective disorder and the implications of the findings for these abnormalities alone patients, the aim of the present study