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In JoVE (1)
Other Publications (9)
- Biological & Pharmaceutical Bulletin
- Gastroenterology
- Neurobiology of Aging
- Colloids and Surfaces. B, Biointerfaces
- Cardiovascular Research
- Journal of Pharmaceutical Sciences
- Toxicology in Vitro : an International Journal Published in Association with BIBRA
- Drug Metabolism and Pharmacokinetics
- Expert Opinion on Drug Metabolism & Toxicology
Articles by Katalin Kis in JoVE
JoVE General
Genomic Transformation of the Picoeukaryote Ostreococcus tauri
1SynthSys, University of Edinburgh, 2Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Paris 06, 3UMR 7621, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, Banyuls-sur-Mer, Université Pierre et Marie Curie, Paris 06
This article describes genetic transformation of the unicellular marine alga Ostreococcus tauri by electroporation. This eukaryotic organism is an effective model platform for higher plants, possesing greatly reduced genomic and cellular complexity and being readily amenable to both cell culture and chemical biology.
Other articles by Katalin Kis on PubMed
Kinetic Characterization of Sulfasalazine Transport by Human ATP-binding Cassette G2
The pharmacokinetics of sulfasalazine, an anti-inflammatory drug is influenced by ATP-binding cassette G2 (ABCG2) (breast cancer resistance protein (BCRP), mitoxantrone resistance protein (MXR)) both in vitro and clinically. Due to its low passive permeability, the intracellular concentration of sulfasalazine is dependent on uptake transporters, rendering the characterization of transporter specific interactions in cell based experimental systems difficult. Applying membrane assays a detailed kinetic analysis of sulfasalazine ABCG2 interaction was conducted and Km values of 0.70 +/- 0.03 microM and 0.66 +/- 0.08 microM were obtained at pH 7.0 and pH 5.5, respectively.
Experimentally Derived Metastasis Gene Expression Profile Predicts Recurrence and Death in Patients with Colon Cancer
Staging inadequately predicts metastatic risk in patients with colon cancer. We used a gene expression profile derived from invasive, murine colon cancer cells that were highly metastatic in an immunocompetent mouse model to identify patients with colon cancer at risk of recurrence.
Beta Amyloid and Hyperphosphorylated Tau Deposits in the Pancreas in Type 2 Diabetes
Strong epidemiologic evidence suggests an association between Alzheimer disease (AD) and type 2 diabetes. To determine if amyloid beta (Abeta) and hyperphosphorylated tau occurs in type 2 diabetes, pancreas tissues from 21 autopsy cases (10 type 2 diabetes and 11 controls) were analyzed. APP and tau mRNAs were identified in human pancreas and in cultured insulinoma beta cells (INS-1) by RT-PCR. Prominent APP and tau bands were detected by Western blotting in pancreatic extracts. Aggregated Abeta, hyperphosphorylated tau, ubiquitin, apolipoprotein E, apolipoprotein(a), IB1/JIP-1 and JNK1 were detected in Langerhans islets in type 2 diabetic patients. Abeta was co-localized with amylin in islet amyloid deposits. In situ beta sheet formation of islet amyloid deposits was shown by infrared microspectroscopy (SIRMS). LPS increased APP in non-neuronal cells as well. We conclude that Abeta deposits and hyperphosphorylated tau are also associated with type 2 diabetes, highlighting common pathogenetic features in neurodegenerative disorders, including AD and type 2 diabetes and suggesting that Abeta deposits and hyperphosphorylated tau may also occur in other organs than the brain.
Hydrophobization of Bovine Serum Albumin with Cationic Surfactants with Different Hydrophobic Chain Length
The interaction between bovine serum albumin (BSA) and cationic surfactants with different chain length was investigated. The hydrodynamic diameters, electrokinetic potentials, as well as the fluorescence emission properties of the protein-surfactant complexes with different hydrophobic character were studied. Dynamic light scattering was applied to determine how the size and electrokinetic potential of the protein aggregates changes due to surfactant loading. It was found that by increasing the chain length of the surfactant the required amount of the surfactant for total aggregation of the system is decreased dramatically, which means that in the course on the aggregation process hydrophobic effects should be considered and it was further proved with fluorescence emission intensity measurements. By changing the pH of the protein solution the contribution of the electrostatic interactions to the aggregation processes was studied. It was showed that both hydrophobic and electrostatic interactions are present in the protein-cationic surfactant interaction.
Deletion of the Metabolic Transcriptional Coactivator PGC1β Induces Cardiac Arrhythmia
Peroxisome proliferator-activated receptor-γ coactivators PGC1α and PGC1β modulate mitochondrial biogenesis and energy homeostasis. The function of these transcriptional coactivators is impaired in obesity, insulin resistance, and type 2 diabetes. We searched for transcriptomic, lipidomic, and electrophysiological alterations in PGC1β(-/-) hearts potentially associated with increased arrhythmic risk in metabolic diseases.
Ivermectin Interacts with Human ABCG2
Ivermectin is an antiparasitic drug frequently administered to humans. It has a limited brain exposure that is attributed to the efflux activity of ABCB1/Abcb1. ABCG2/Abcg2 is also a major transporter present in most pharmacologically important barriers. However, interaction of ivermectin with Abcg2 shows species specificity and in many studies was confounded by the masking effect of ABCB1/Abcb1. In this study using cellular and membrane assays we show that ivermectin displays a high-affinity interaction with human ABCG2 with IC(50) values in the 1-1.5 µM range. This interaction may have implications in human ABCG2-mediated drug-drug interactions of ivermectin.
BSEP Inhibition - In Vitro Screens to Assess Cholestatic Potential of Drugs
Bile salt export pump (BSEP, ABC11) is a membrane protein that is localized in the cholesterol-rich canalicular membrane of hepatocytes. Its function is to eliminate unconjugated and conjugated bile acids/salts from hepatocyte into the bile. In humans there is no compensatory mechanism for the loss of this transporter. Mutations of BSEP result in a genetic disease, called progressive familial intrahepatic cholestasis type 2 (PFIC2), that is characterized with decreased biliary bile salt secretion, leading to decreased bile flow and accumulation of bile salts inside the hepatocyte, inflicting damage. BSEP inhibitor drugs produce similar bile salt retention that may lead to severe cholestasis and liver damage. Drug-induced liver injury is a relevant clinical issue, in severe cases ending in liver transplantation. Therefore, measurement of BSEP inhibition by candidate drugs has high importance in drug discovery and development. Although several methods are suitable to detect BSEP-drug interactions, due to interspecies differences in bile acid composition, differences in hepatobiliary transporter modulation, they have limitations. This review summarizes appropriate in vitro methods that could be able to predict BSEP-drug candidate interactions in humans before the start of clinical phases.
ABCG2 Modulates Chlorothiazide Permeability in Vitro - Characterization of the Interaction
We are showing that chlorothiazide, a diuretic is an ABCG2 substrate. It is a Biopharmaceutics Classification System / Biopharmaceutics Drug Distribution and Classification System (BCS / BDDCS) Class IV drug with low bioavailability. Therefore, we tested if chlorothiazide interacts with major apically located intestinal efflux transporters. Our data show that chlorothiazide is transported by ABCG2 with a K(m) value of 334.6 µM and does not interact with ABCB1, ABCC2. The chlorothiazide - ABCG2 interaction results in a vectorial transport in MDCKII-BCRP and Caco-2 cells with efflux ratios of 36 and 8.1 respectively. Inhibition of ABCG2 in Caco-2 cells reduced the efflux ratio to 1.4 suggesting that ABCG2 plays a role in limiting chlorothiazide bioavailability in humans.
Efflux Transporters in the Blood-brain Interfaces - in Vitro and in Vivo Methods and Correlations
Introduction: Sufficient brain exposure is crucial to the success of CNS drugs. The twofold greater attrition rate in clinical development of CNS drugs over the respective attrition rate of non-CNS drugs is due to lack of efficacy. It is generally thought that poor brain exposure is at least partly responsible for this, as the concentration-time profile at the brain target site is critical for efficacy. Efflux transporters in the blood-brain interfaces play a crucial role in modulation of permeability of drugs across these interfaces. Validation of preclinical tools to correctly predict brain exposure in humans is essential. Areas covered: This review summarizes in vitro and in vivo tools to detect and characterize interactions of drugs with efflux transporters relevant to blood-brain interfaces. Furthermore, the article discusses the strengths and weaknesses of these methods and the limitations of their application, in addition to covering in vitro - in vivo correlations. Expert opinion: A more detailed validation of in vitro efflux transporter assays employing primary brain endothelial cultures is needed. This should go along with mapping uptake transporters expressed in the blood-brain interfaces. With the availability of specific inhibitors, utilization of in vivo methods such as brain microdialysis is increasing. Once transporter-humanized mice are available, we may witness a further increase in applications of in vivo methods.
