Search results for "porte"

Reversal of multidrug resistance by Marsdenia tenacissima and its main active ingredients polyoxypregnanes.

2016

Abstract Ethnopharmacological relevance Multidrug resistance (MDR) of cancer is often associated with the overexpression of ATP-binding cassette (ABC) transporters, such as P-glycoprotein (P-gp), multidrug resistance-associated protein-1 (MRP-1) and breast cancer resistance protein (BCRP or ABCG2), in cancer cells, which facilitates the active efflux of a wide variety of chemotherapeutic drugs out of the cells. Marsdenia tenacissima is a traditional Chinese medicinal herb that has long been clinically used for treatment of cancers, particularly in combinational use with anticancer drugs. Polyoxypregnanes (POPs) are identified as main constituents of this herb, and three of them have been re…

A Physiology-Based Model of Human Bile Acid Metabolism for Predicting Bile Acid Tissue Levels After Drug Administration in Healthy Subjects and BRIC …

2019

Drug-induced liver injury (DILI) is a matter of concern in the course of drug development and patient safety, often leading to discontinuation of drug-development programs or early withdrawal of drugs from market. Hepatocellular toxicity or impairment of bile acid (BA) metabolism, known as cholestasis, are the two clinical forms of DILI. Whole-body physiology-based modelling allows a mechanistic investigation of the physiological processes leading to cholestasis in man. Objectives of the present study were: (1) the development of a physiology-based model of the human BA metabolism, (2) population-based model validation and characterisation, and (3) the prediction and quantification of alter…

A useful procedure for detection of polyamines in biological samples as a potential diagnostic tool in cancer diagnosis

2017

Abstract Background Polyamines present in human body are frequently considered as markers of occurrence of cancer. Therefore, the availability of simple and efficient method for determination of their level in body liquids and tissues is of some interest. Methods Supported liquid membrane technology coupled with HPLC seems to be an appropriate technique to follow the level of polyamines in human blood and urine. Thus, the membranes of two different geometries: flat sheet and hollow fiber were studied as a mean for separation and enrichment of studied polyamines from urine and tissue samples in order to prepare samples to be analyzed by HPLC. Conclusions Developed extraction systems offer an…

Taste of Fat: A Sixth Taste Modality?

2015

International audience; An attraction for palatable foods rich in lipids is shared by rodents and humans. Over the last decade, the mechanisms responsible for this specific eating behavior have been actively studied, and compelling evidence implicates a taste component in the orosensory detection of dietary lipids [i.e., long-chain fatty acids (LCFA)], in addition to textural, olfactory, and postingestive cues. The interactions between LCFA and specific receptors in taste bud cells (TBC) elicit physiological changes that affect both food intake and digestive functions. After a short overview of the gustatory pathway, this review brings together the key findings consistent with the existence…

ESC-Derived BDNF-Overexpressing Neural Progenitors Differentially Promote Recovery in Huntington's Disease Models by Enhanced Striatal Differentiation

2016

Summary Huntington's disease (HD) is characterized by fatal motoric failures induced by loss of striatal medium spiny neurons. Neuronal cell death has been linked to impaired expression and axonal transport of the neurotrophin BDNF (brain-derived neurotrophic factor). By transplanting embryonic stem cell-derived neural progenitors overexpressing BDNF, we combined cell replacement and BDNF supply as a potential HD therapy approach. Transplantation of purified neural progenitors was analyzed in a quinolinic acid (QA) chemical and two genetic HD mouse models (R6/2 and N171-82Q) on the basis of distinct behavioral parameters, including CatWalk gait analysis. Explicit rescue of motor function by…

Functional inhibition of Oct leads to HNF4α upregulation

2021

Organic cation transporters (human, OCT; mouse, Oct) are responsible for the intracellular uptake and detoxification of a broad spectrum of endogenous and exogenous substrates. The OCT1 gene SLC22A1 (human; mouse, Scl22a1) is transactivated by hepatocyte nuclear factor 4α (human, HNF4α; mouse, Hnf4α). HNF4α is a master regulator of hepatocyte differentiation and is frequently associated with hepatocellular carcinoma (HCC). In addition, the downregulation of HNF4α is associated with enhanced fibrogenesis. Our recent study revealed that hepatocarcinogenesis and fibrosis were enhanced with the loss of Oct3 (gene, Slc22a3). Notably, differences in Hnf4α expression, and in cholestasis and fibros…

The Sea Urchin sns5 Chromatin Insulator Shapes the Chromatin Architecture of a Lentivirus Vector Integrated in the Mammalian Genome.

2016

Lentivirus vectors are presently the favorite vehicles for therapeutic gene transfer in hematopoietic cells. Nonetheless, these vectors integrate randomly throughout the genome, exhibiting variegation of transgene expression due to the spreading of heterochromatin into the vector sequences. Moreover, the cis-regulatory elements harbored by the vector could disturb the proper transcription of resident genes neighboring the integration site. The incorporation of chromatin insulators in flanking position to the transferred unit can alleviate both the above-mentioned dangerous effects, due to the insulator-specific barrier and enhancer-blocking activities. In this study, we report the valuable …

Where do we go from here? Membrane protein research beyond the structure-function horizon.

2018

The 40-Year Mystery of Insect Odorant-Binding Proteins

2021

International audience; The survival of insects depends on their ability to detect molecules present in their environment. Odorant-binding proteins (OBPs) form a family of proteins involved in chemoreception. While OBPs were initially found in olfactory appendages, recently these proteins were discovered in other chemosensory and non-chemosensory organs. OBPs can bind, solubilize and transport hydrophobic stimuli to chemoreceptors across the aqueous sensilla lymph. In addition to this broadly accepted “transporter role”, OBPs can also buffer sudden changes in odorant levels and are involved in hygro-reception. The physiological roles of OBPs expressed in other body tissues, such as mouthpar…

Cooperation of Secondary Transporters and Sensor Kinases in Transmembrane Signalling

2016

Many membrane-bound sensor kinases require accessory proteins for function. The review describes functional control of membrane-bound sensors by transporters. The C4-dicarboxylate sensor kinase DcuS requires the aerobic or anaerobic C4-dicarboxylate transporters DctA or DcuB, respectively, for function and forms DctA/DcuS or DcuB/DcuS sensor complexes. Free DcuS is in the permanent (ligand independent) ON state. The DctA/DcuS and DcuB/DcuS complexes, on the other hand, control expression in response to C4-dicarboxylates. In DctA/DcuS, helix 8b of DctA and the PASC domain of DcuS are involved in interaction. The stimulus is perceived by the extracytoplasmic sensor domain (PASP) of DcuS. The …