Estrogen increases the transcription of human alpha 2-Heremans-Schmid-glycoprotein by an interplay of estrogen receptor alpha and activator protein-1
OSTEOPOROSIS INTERNATIONAL
Authors: Qiu, C.; Liu, X.; Wang, J.; Zhao, Y.; Fu, Q.
Abstract
The expression of alpha 2-Heremans-Schmid-glycoprotein (AHSG) was estrogen responsive in oophorectomized (OVX) osteopenic rats and HepG2 cells. Estrogen receptor alpha (ER alpha) interacted with the c-Jun/c-Fos heterodimer and indirectly associated with the -1488/-1482 activator protein-1 (AP-1) motif of the AHSG promoter. Estrogen increased c-Jun/c-Fos expression via the mitogen-activated protein kinase (MAPK) pathway. AHSG is a hepatic secretory protein implicated in the regulation of bone homeostasis. Serum AHSG in women has been reported to decrease after menopause and increase with estrogen therapy. The detailed regulatory mechanism of estrogen on AHSG is unclear. A postmenopausal osteoporosis model was generated in OVX rats. Skeletal parameters were determined by automatic biochemical analysis and dual X-ray absorptiometry. The expression of AHSG was evaluated by ELISA, real-time PCR, and Western blot. The 1.5-kb 5'-promoter region of AHSG was analyzed by serial truncation and luciferase assays. The putative -1488/-1482 AP-1 responsive element was identified by electrophoresis mobility shift assay (EMSA). Chromatin immunoprecipitation (ChIP), re-ChIP, and co-immunoprecipitation (Co-IP) were used to characterize the interaction of ER alpha and AP-1 at the -1488/-1482 AP-1 binding site. The MAPK pathway was evaluated using a specific inhibitor and active transfection. The expression of AHSG was estrogen responsive in both OVX rats and estradiol (E2)/ER alpha-treated HepG2 cells. E2/ER alpha most prominently increased luciferase activity of a construct with a putative -1488/-1482 AP-1 binding element. ER alpha interacted with the c-Jun/c-Fos heterodimer and indirectly associated with the -1488/-1482 AP-1 motif of the AHSG promoter. c-Jun/c-Fos expression was increased via the MAPK pathway by E2/ER alpha. Estrogen activated the transcription of AHSG through an indirect binding of ER alpha to the -1488/-1482 AP-1 binding element, with the c-Jun/c-Fos heterodimers.
Steady and dynamic shear rheological behavior of semi dilute Alyssum homolocarpum seed gum solutions: influence of concentration, temperature and heating-cooling rate
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
Authors: Alaeddini, Behzad; Koocheki, Arash; Milani, Jafar Mohammadzadeh; Razavi, Seyed Mohammad Ali; Ghanbarzadeh, Babak
Abstract
BACKGROUNDAlyssum homolocarpum seed gum (AHSG) solution exhibits high viscosity at low shear rates and has anionic features. However there is no information regarding the flow and dynamic properties of this gum in semi-dilute solutions. The present study aimed to investigate the dynamic and steady shear behavior of AHSG in the semi-dilute region. RESULTSThe viscosity profile demonestrated a shear thinning behavior at all temperatures and concentrations. An increase in the AHSG concentration was acompanied by an increase in the pseudoplasticity degree, whereas, by increasing the temperature, the pseudoplasticity of AHSG decreased. At low gum concentration, solutions had more viscosity dependence on temperature. The mechanical spectra obtained from the frequency sweep experiment demonstrated viscoelastic properties for gum solutions. AHSG solutions showed typical weak gel-like behavior, revealing G' greater than G' within the experimental range of frequency (Hz), with slight frequency dependency. The influence of temperature on viscoelastic properties of AHSG solutions was studied during both heating (5-85 degrees C) and cooling (85-5 degrees C) processes. The complex viscosity of AHSG was greater compared to the apparent viscosity, indicating the disruption of AHSG network structure under continuous shear rates and deviation from the Cox-Merz rule. During the initial heating, the storage modulus showed a decreasing trend and, with a further increase in temperature, the magnitude of storage modulus increased. The influence of temperature on the storage modulus was considerable when a higher heating rate was applied. CONCLUSIONAHSG can be applied as a thickening and stabilizing agents in food products that require good stability against temperature. (c) 2017 Society of Chemical Industry