Transcriptional Regulation of CYP3A4 and CYP2D6 by Small Heterodimer Partner

Small heterodimer partner (SHP) is a transcriptional corepressor of a number of ligand regulated nuclear receptors (NR) and orphan receptors, and represses their target genes expression. Studying transcriptional regulation mechanism of important DMEs can help better understand and predict of the elimination of drugs, and effectively achieve personalized medicine. Farnesoid X receptor (FXR) functions as a regulator of bile acid and lipid homeostasis, and is recognized as a promising therapeutic target for metabolic diseases. SHP is the target gene of several signaling pathways, and various inducers significantly increase its expression. In Chapter 1, we investigated the effect of FXR activation on the expression of the major drug-metabolizing enzyme, CYP3A4. The results in Chapter 1 showed that in human hepatocytes, treatment of GW4064 (1 μM) for 48 hours resulted in 75% decrease in CYP3A4 mRNA expression and 25% decrease in CYP3A4 activity, accompanied by ~3-fold increase in SHP mRNA expression. In HepG2 cells, SHP repressed transactivation of CYP3A4 promoter by pregnane X receptor (PXR), constitutive androstane receptor (CAR), and glucocorticoid receptor (GR). Interestingly, GW4064 did not repress expression of CYP2B6, another target gene of PXR and CAR; GW4064 was shown to enhance CYP2B6 promoter activity. In conclusion, GW4064 represses CYP3A4 expression in human hepatocytes, potentially through upregulation of SHP expression and subsequent repression of CYP3A4 promoter activity. Clinically significant drug-drug interaction involving FXR agonists and CYP3A4 substrates may occur. In Chapter 2, we characterized the effect of ATRA, another potential inducer of SHP, on CYP2D6 expression in vitro and in vivo. Results showed in both human hepatocytes and transgenic mices, CYP2D6 mRNA expression level was significantly repressed by ~70% in vitro, and by ~50% in vivo. The repressed CYP2D6 expression is accompanied by induced SHP expression which was elevated by ~3-fold in vitro and ~5-fold in vivo, respectively. The correlation between SHP and CYP2D6 was further confirmed using mice with Tg-CYP2D6 with Shp knockout compared with Tg- CYP2D6 wild-type mice. Overall, the results indicated that SHP is a key regulator in ATRA- induced CYP2D6 repression

Transcriptional Regulation of CYP3A4 and CYP2D6 by Small Heterodimer Partner

Small heterodimer partner (SHP) is a transcriptional corepressor of a number of ligand regulated nuclear receptors (NR) and orphan receptors, and represses their target genes expression. Studying transcriptional regulation mechanism of important DMEs can help better understand and predict of the elimination of drugs, and effectively achieve personalized medicine. Farnesoid X receptor (FXR) functions as a regulator of bile acid and lipid homeostasis, and is recognized as a promising therapeutic target for metabolic diseases. SHP is the target gene of several signaling pathways, and various inducers significantly increase its expression. In Chapter 1, we investigated the effect of FXR activation on the expression of the major drug-metabolizing enzyme, CYP3A4. The results in Chapter 1 showed that in human hepatocytes, treatment of GW4064 (1 μM) for 48 hours resulted in 75% decrease in CYP3A4 mRNA expression and 25% decrease in CYP3A4 activity, accompanied by ~3-fold increase in SHP mRNA expression. In HepG2 cells, SHP repressed transactivation of CYP3A4 promoter by pregnane X receptor (PXR), constitutive androstane receptor (CAR), and glucocorticoid receptor (GR). Interestingly, GW4064 did not repress expression of CYP2B6, another target gene of PXR and CAR; GW4064 was shown to enhance CYP2B6 promoter activity. In conclusion, GW4064 represses CYP3A4 expression in human hepatocytes, potentially through upregulation of SHP expression and subsequent repression of CYP3A4 promoter activity. Clinically significant drug-drug interaction involving FXR agonists and CYP3A4 substrates may occur. In Chapter 2, we characterized the effect of ATRA, another potential inducer of SHP, on CYP2D6 expression in vitro and in vivo. Results showed in both human hepatocytes and transgenic mices, CYP2D6 mRNA expression level was significantly repressed by ~70% in vitro, and by ~50% in vivo. The repressed CYP2D6 expression is accompanied by induced SHP expression which was elevated by ~3-fold in vitro and ~5-fold in vivo, respectively. The correlation between SHP and CYP2D6 was further confirmed using mice with Tg-CYP2D6 with Shp knockout compared with Tg- CYP2D6 wild-type mice. Overall, the results indicated that SHP is a key regulator in ATRA- induced CYP2D6 repression

Transcriptional Regulation of CYP3A4 and CYP2D6 by Small Heterodimer Partner

Small heterodimer partner (SHP) is a transcriptional corepressor of a number of ligand regulated nuclear receptors (NR) and orphan receptors, and represses their target genes expression. Studying transcriptional regulation mechanism of important DMEs can help better understand and predict of the elimination of drugs, and effectively achieve personalized medicine. Farnesoid X receptor (FXR) functions as a regulator of bile acid and lipid homeostasis, and is recognized as a promising therapeutic target for metabolic diseases. SHP is the target gene of several signaling pathways, and various inducers significantly increase its expression. In Chapter 1, we investigated the effect of FXR activation on the expression of the major drug-metabolizing enzyme, CYP3A4. The results in Chapter 1 showed that in human hepatocytes, treatment of GW4064 (1 μM) for 48 hours resulted in 75% decrease in CYP3A4 mRNA expression and 25% decrease in CYP3A4 activity, accompanied by ~3-fold increase in SHP mRNA expression. In HepG2 cells, SHP repressed transactivation of CYP3A4 promoter by pregnane X receptor (PXR), constitutive androstane receptor (CAR), and glucocorticoid receptor (GR). Interestingly, GW4064 did not repress expression of CYP2B6, another target gene of PXR and CAR; GW4064 was shown to enhance CYP2B6 promoter activity. In conclusion, GW4064 represses CYP3A4 expression in human hepatocytes, potentially through upregulation of SHP expression and subsequent repression of CYP3A4 promoter activity. Clinically significant drug-drug interaction involving FXR agonists and CYP3A4 substrates may occur. In Chapter 2, we characterized the effect of ATRA, another potential inducer of SHP, on CYP2D6 expression in vitro and in vivo. Results showed in both human hepatocytes and transgenic mices, CYP2D6 mRNA expression level was significantly repressed by ~70% in vitro, and by ~50% in vivo. The repressed CYP2D6 expression is accompanied by induced SHP expression which was elevated by ~3-fold in vitro and ~5-fold in vivo, respectively. The correlation between SHP and CYP2D6 was further confirmed using mice with Tg-CYP2D6 with Shp knockout compared with Tg- CYP2D6 wild-type mice. Overall, the results indicated that SHP is a key regulator in ATRA- induced CYP2D6 repression

Gene expression of limept Cellana toreuma in different thermal and osmotic conditions

Gene expression of limept Cellana toreuma in different thermal and osmotic condition

Ethylene Dimerization/Polymerization Catalyzed by (Adamantylimido)vanadium(V) Complexes Containing (2-Anilidomethyl)pyridine Ligands: Factors Affecting the Ethylene Reactivity

V­(N-1-adamantyl)­Cl₂[2-(2,6-Me₂C₆H₃)­NCH₂(C₅H₄N)] showed both remarkable activity and selectivity (from 92 through >99.5% selectivity) in ethylene dimerization in the presence of MAO or MMAO, and the activity increased linearly upon increasing the ethylene pressure. The same reaction in the presence of Et₂AlCl or Me₂AlCl afforded ultrahigh molecular weight polyethylene. Both the ESR spectra and the ⁵¹V NMR spectra suggest that the chelate anionic donor ligand plays an important role in stabilization of the oxidation state in the catalyst solution even containing Al alkyls

Changes in fluorescence intensities of MC3T3-E1 cells loaded with Calcium GreenTM-1.

<p>Time-lapse sequence images showing calcium influx in the cells before pulsed ultrasound radiation (A), at the start (B) of radiation and during the radiation (C and D). Compared to cells without ultrasound radiation, the pulsed ultrasound evoked a significant increase in intracellular calcium levels (E). Dotted lines represent duration of radiation on- and off-switch, respectively. Scale bar, 10 µm.</p

Primary cilium projections from the surface of an MC3T3-E1 osteoblast and its bending during radiation of pulsed ultrasound.

<p>The upper panel shows primary cilium stained with an antibody against acetylated α-tubulin (red) (arrowheads, A and D), cell body stained with CMFDA (green) (B and D) and nucleus stained with DAPI (blue) (C and D) in a MC3T3-E1 osteoblast. The lower panel shows the top views of bending movement of a primary cilium (arrowheads) extending from the surface of an MC3T3-E1 osteoblast before (E) and during (F and G) application of pulsed ultrasound from top to bottom. Scale bar, 10 µm.</p

Schematic diagram of the transducer assembly. A

<p>: Spherical transducer with coupling cone and a centrally attached laser guideline light. The ellipsoidal acoustic focal zone covers approximately 4 mm axially and 0.4 mm transversely at the half-pressure points. <b>B</b>: Normalized pressure distribution through the culture dish for the single element on the radial plane at the distance of 62.75 mm of the transducer’s surface. <b>C</b>: The focal point of focused ultrasound guided by red laser light in the middle field of view of the microscope objective. Scale bar, 50 µm.</p

Calculated Dynamic Parameters for Different Acoustical Power.

<p>Notes. Values for velocity and τ represent mean ± SE. The radius of the focal region is 0.2 mm. Efficiency of power conversion is 68.8%. Fluid shear stress and radiation force were calculated according to both formulas (see text for details).</p

Schematic diagram of experimental setup for spatiotemporal measurements of the effects of acoustic radiation force on MC3T3-E1 cells.

<p>The setup includes an inverted microscope and a high intensity focused ultrasound system. Movement of the spherical transducer is controlled by the three-dimensional support framework.</p