Effect of Ion-Pair Formation with Bile Salts on the In Vitro Cellular Transport of Berberine

Hye-Won Chae,김인화,진효언,김대덕,정석재,심창구 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.1

The objective of this study was to examine the effect of ion-pair complexation with endogenous bile salts on the transport of a quarternary ammonium organic cationic (OC) drug, berberine, across the Caco-2 and LLC-PK1 cell monolayers. The basolateral-to-apical (BL-AP) transport of berberine in Caco-2 cells was temperature dependent and 10-fold higher than that of the apical-to-basolateral (AP-BL) transport. Similar results were observed for the transport of berberine across the LLC-PK1 cells. Moreover, the BL-AP transport in the Caco-2 cells was significantly reduced by the cis-presence of P-glycoprotein (P-gp) inhibitors such as cyclosporine A, verapamil, and digoxin. These results suggest that an efflux transporter, probably P-gp, is involved in the Caco-2 cell transport. The Km and Vmax values for the carrier-mediated transport were estimated to be 83.4 mM and 7640 pmole/h/cm2, respectively. The apparent partition coefficient (APC) of berberine between n-octanol and a phosphate buffer (pH 7.4) was increased by the presence of an organic anion (OA), taurodeoxycholate (TDC, a bile salt), suggesting the formation of a lipophilic ion-pair complex between an OC (berberine) and an OA (TDC). Despite the ion-pair complexation, however, the BL-AP transport of berberine across the Caco-2 and LLC-PK1 cells was not altered by the cis-presence of bile salts or the rat bile juice. This is consistent with the reportedly unaltered secretory transport of a quarternary ammonium compound, tributylmethylammonium (TBuMA), across the Caco-2 cell monolayers in the cis-presence of bile salts or the rat bile juice, but not with our previous report in which the secretory transport of TBuMA across the LLC-PK1 cell was increased in the cis-presence of TDC. Therefore, the effect of ion-pair formation with the bile components or bile salts on the secretory transport of OCs appears to depend on the molecular properties of OCs (e.g., molecular weight, lipophilicity and affinity to relevant transporters) and the characteristics of cell strains (e.g., expression and contribution of responsible transporters to the transport).

Effect of Ion-Pair Formation with Bile Salts on the In Vitro Cellular Transport of Berberine

Chae, Hye-Won,Kim, In-Wha,Jin, Hyo-Eon,Kim, Dae-Duk,Chung, Suk-Jae,Shim, Chang-Koo 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.1

The objective of this study was to examine the effect of ion-pair complexation with endogenous bile salts on the transport of a quarternary ammonium organic cationic (OC) drug, berberine, across the Caco-2 and LLC-PK1 cell monolayers. The basolateral-to-apical (BL-AP) transport of berberine in Caco-2 cells was temperature dependent and 10-fold higher than that of the apical-to-basolateral (AP-BL) transport. Similar results were observed for the transport of berberine across the LLC-PK1 cells. Moreover, the BL-AP transport in the Caco-2 cells was significantly reduced by the cis-presence of P-glycoprotein (P-gp) inhibitors such as cyclosporine A, verapamil, and digoxin. These results suggest that an efflux transporter, probably P-gp, is involved in the Caco-2 cell transport. The $K_m$ and $V_{max}$ values for the carrier-mediated transport were estimated to be 83.4 mM and 7640 pmole/h/$cm^2$, respectively. The apparent partition coefficient (APC) of berberine between n-octanol and a phosphate buffer (pH 7.4) was increased by the presence of an organic anion (OA), taurodeoxycholate (TDC, a bile salt), suggesting the formation of a lipophilic ion-pair complex between an OC (berberine) and an OA (TDC). Despite the ion-pair complexation, however, the BL-AP transport of berberine across the Caco-2 and LLC-PK1 cells was not altered by the cis-presence of bile salts or the rat bile juice. This is consistent with the reportedly unaltered secretory transport of a quarternary ammonium compound, tributylmethylammonium (TBuMA), across the Caco-2 cell monolayers in the cis-presence of bile salts or the rat bile juice, but not with our previous report in which the secretory transport of TBuMA across the LLC-PK1 cell was increased in the cis-presence of TDC. Therefore, the effect of ion-pair formation with the bile components or bile salts on the secretory transport of OCs appears to depend on the molecular properties of OCs (e.g., molecular weight, lipophilicity and affinity to relevant transporters) and the characteristics of cell strains (e.g., expression and contribution of responsible transporters to the transport).

아미노산의 능동 수송계에 미치는 $NH_4^{+}$ 이온의 영향

조봉희 한국식물생명공학회 1999 식물생명공학회지 Vol.26 No.2

Glucose - induced arginine transport system was induced by a exogenous application of NH$_4$^+ ion. The uptake rate of arginine (Arg) depended on the external NH$_4$^+ ion concentration. The uptake rate was inhibited by the presence of NH$_4$^+ ion within 1 min, whereas it increased maximally after 30 min. Glucose and NH$_4$^+ ion induced the same arginine transport system. Km value of Arg transport systems was 2 $\mu$M, and V_(max) was 60 $\mu$mol^(-1) . h . g fresh weight^(-1) for NH$_4$^+ ion and 174 $\mu$mol^(-1) . h . g fresh weight^(-1) for glucose induced transport system. But, the transport system of Glu for glucose and NH$_4$^(-1) ion induced had different Km values. Km value of Glu was 285 $\mu$M for glucose - and 58 $\mu$M for NH$_4$^+ ion induced transport system. Thus, NH$_4$^+ ions play a important role as inducer for the glutamine transport system. NH$_4$^+ ion induced glutamine system was inhibited over 90% by cycloheximide. We concluded that a new carrier protein for glutamine was induced by NH$_4$^+ ion.

Structure-dynamic and functional relationships in a Li⁺-transporting sodium‑calcium exchanger mutant

Giladi, Moshe,Lee, Su Youn,Refaeli, Bosmat,Hiller, Reuben,Chung, Ka Young,Khananshvili, Daniel Elsevier 2019 Biochimica et biophysica acta, Bioenergetics Vol.1860 No.3

<P><B>Abstract</B></P> <P>The cell membrane (NCX) and mitochondrial (NCLX) Na<SUP>+</SUP>/Ca<SUP>2+</SUP> exchangers control Ca<SUP>2+</SUP> homeostasis. Eleven (out of twelve) ion-coordinating residues are highly conserved among eukaryotic and prokaryotic NCXs, whereas in NCLX, nine (out of twelve) ion-coordinating residues are different. Consequently, NCXs exhibit high selectivity for Na<SUP>+</SUP> and Ca<SUP>2+</SUP>, whereas NCLX can exchange Ca<SUP>2+</SUP> with either Na<SUP>+</SUP> or Li<SUP>+</SUP>. However, the underlying molecular mechanisms and physiological relevance remain unresolved. Here, we analyzed the NCX_Mj-derived mutant NCLX_Mj (with nine substituted residues) imitating the ion selectivity of NCLX. Site-directed fluorescent labeling and ion flux assays revealed the nearly symmetric accessibility of ions to the extracellular and cytosolic vestibules in NCLX_Mj (K<SUB>int</SUB> = 0.8–1.4), whereas the extracellular vestibule is predominantly accessible to ions (K<SUB>int</SUB> = 0.1–0.2) in NCX_Mj. HDX-MS (hydrogen-deuterium exchange mass-spectrometry) identified symmetrically rigidified core helix segments in NCLX_Mj, whereas the matching structural elements are asymmetrically rigidified in NCX_Mj. The HDX-MS analyses of ion-induced conformational changes and the mutational effects on ion fluxes revealed that the “Ca<SUP>2+</SUP>-site” (S<SUB>Ca</SUB>) of NCLX_Mj binds Na<SUP>+</SUP>, Li<SUP>+</SUP>, or Ca<SUP>2+</SUP>, whereas one or more additional Na<SUP>+</SUP>/Li<SUP>+</SUP> sites of NCLX_Mj are incompatible with the Na<SUP>+</SUP> sites (S<SUB>ext</SUB> and S<SUB>int</SUB>) of NCX_Mj. Thus, the replacement of ion-coordinating residues in NCLX_Mj alters not only the ion selectivity of NCLX_Mj, but also the capacity and affinity for Na<SUP>+</SUP>/Li<SUP>+</SUP> (but not for Ca<SUP>2+</SUP>) binding, bidirectional ion-accessibility, the response of the ion-exchange to membrane potential changes, and more. These structure-controlled functional features could be relevant for differential contributions of NCX and NCLX to Ca<SUP>2+</SUP> homeostasis in distinct sub-cellular compartments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Distinct structural elements control ion selectivity in the Na<SUP>+</SUP>/Ca<SUP>2+</SUP> exchanger. </LI> <LI> Residue-based changes in ion-selectivity specifically alter conformational patterns. </LI> <LI> Structure-dynamic variances at distinct sites are reflected in functional diversity. </LI> <LI> Conformational dynamics of apo-protein predefines a degree of functional asymmetry. </LI> <LI> The loss in ion selectivity has relatively small effects on the transport rates. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of specific adsorption on the electrochemical on/off switching of ion transport

Piao, H.,Choi, D.,Wang, W.,Son, Y. Pergamon Press 2014 ELECTROCHIMICA ACTA Vol.146 No.-

A number of ion separation methods successfully separate ions by controlling the ion's transport. In general, transport rate of ions depends on their charge, size or hydrated radii. However, methylene blue (MB) used in this study showed different transport tendency compared to other ions. The results indicate that the transport of MB is affected by its adsorption property. Thus, we tried to elucidate the special transport mechanism of MB in detail. The conducting polymer modified membrane used in this study was prepared by the electrochemical polymerization of pyrrole on a gold-sputtered polycarbonate (PC) membrane in aqueous solution. Characterization of the polypyrrole (PPy) modified membrane was performed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX). The transport of MB through the PPy membrane was controlled by applied potentials. The concentration change of MB in permeated cell was detected by high performance liquid chromatography (HPLC) equipped with a UV-Vis detector.

Numerical estimation of ion transport and electroosmotic flow around a pair of cylindrical electrodes in a microchannel using immersed boundary method

Fernandes, Dolfred Vijay,Kang, Sang-Mo,Suh, Yong-Kweon 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.12

This paper investigates the ion transport and electroosmotically induced flow around the cylindrical electrodes under both direct current (DC) and alternating current (AC) fields. The Poisson-Nernst-Plank (PNP) equations governing the ion transport around the ideally polarizable electrodes are solved numerically by neglecting the Stem layer effect. The fractional-step (FS) based decoupled solver is used in time integration of the ion-transport equations. A new immersed boundary (IB) methodology is described for imposing no-flux boundary conditions of ion concentration on the electrodes. A fully implicit coupled solver is also developed for calculating the ion transport around a pair of rectangular electrodes. The validity of the decoupled solver is verified by comparing its results with those obtained from the coupled solver. For further confirmation of the validity, the results are also compared with those obtained from the Poisson-Boltzmann model and both results are found to be in excellent agreement. The electroosmotically induced flow field is studied by numerically solving the Stokes equations. The system attains a steady state under DC, where the conduction term of ion transport is balanced by the diffusion term. Until the system attains a steady state for a few ms for the case of DC, fluid flow is induced. The electroosmotic flow under AC is more interesting, in that instantaneous flow oscillates with the frequency double of the applied field and a nonzero steady velocity field persists.

Innovative Polymer Nanocomposite Electrolytes: Nanoscale Manipulation of Ion Channels by Functionalized Graphenes

Choi, Bong Gill,Hong, Jinkee,Park, Young Chul,Jung, Doo Hwan,Hong, Won Hi,Hammond, Paula T.,Park, HoSeok American Chemical Society 2011 ACS NANO Vol.5 No.6

<P>The chemistry and structure of ion channels within the polymer electrolytes are of prime importance for studying the transport properties of electrolytes as well as for developing high-performance electrochemical devices. Despite intensive efforts on the synthesis of polymer electrolytes, few studies have demonstrated enhanced target ion conduction while suppressing unfavorable ion or mass transport because the undesirable transport occurs through an identical pathway. Herein, we report an innovative, chemical strategy for the synthesis of polymer electrolytes whose ion-conducting channels are physically and chemically modulated by the ionic (not electronic) conductive, functionalized graphenes and for a fundamental understanding of ion and mass transport occurring in nanoscale ionic clusters. The functionalized graphenes controlled the state of water by means of nanoscale manipulation of the physical geometry and chemical functionality of ionic channels. Furthermore, the confinement of bound water within the reorganized nanochannels of composite membranes was confirmed by the enhanced proton conductivity at high temperature and the low activation energy for ionic conduction through a Grotthus-type mechanism. The selectively facilitated transport behavior of composite membranes such as high proton conductivity and low methanol crossover was attributed to the confined bound water, resulting in high-performance fuel cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-6/nn2013113/production/images/medium/nn-2011-013113_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn2013113'>ACS Electronic Supporting Info</A></P>

Changes of Carrier Density and Mobility in ALD-ZnO Thin Films after Nitrogen-ion Implantation

김희수,이두형,노승정 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.4

ZnO has attracted much attention due to its highly efficient UV emission resulting from its large band gap of 3.37 eV, large exciton binding energy of 60 meV, and low power threshold for optical pumping at room temperature. In this study, ZnO films were grown on glass substrates at a substrate temperature of 190 ℃ by using atomic layer deposition (ALD), and changes in the carrier density and mobility of the ZnO films after nitrogen-ion implantation were investigated. For ZnO film deposition, diethyl zinc was used as the metal-organic precursor, H_2O as the oxidant, and Ar as the carrier and the purge gas. The film thickness after 1,800 cycles was measured to be approximately 450 nm, giving a growth rate of 0.25 nm/cycle. For nitrogen-ion implantation, the nitrogen-ion energy of 130 keV was determined by numerical simulation using the transport of ions in matter (TRIM) code, and the ZnO films were doped by using nitrogen-ion implantation at fluences of 1.0 × 10^(15) ions/cm^2 ∼ 1.0 × 10^(17) ions/cm^2. The change in the carrier density of the ZnO film with increasing irradiation influence was found to be significant. At a fluence of 1.0 × 10^(17) ions/cm^2, a drastic carrier density change of six orders of magnitude, from ∼10^(19) cm^(−3) to ∼10^(13) cm^(−3), was realized. The change in the magnitude of the mobility was found to be relatively small, and the magnitude was reduced by up to 80%.

Decreased Secretory Transport of a Quarternary Ammonium, TBuMA, across LLC-PK1 Cells by the Anionic Kidney Extract

Shim, Won-Sik,Choi, Min-Koo,Kim, In-Wha,Kwon, Tae-Sik,Song, Im-Sook,Han, Liwei,Kim, Dae-Duk,Chung, Suk-Jae,Shim, Chang-Koo 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.5

The effect of organic anionic (OA) fractions of various rat organ tissues on the apparent partition coefficients (APC) of quarternary ammoniums (QAs) between n-octanol and phosphate buffer (pH 7.4) and QAs transport across the LLC-PK1 cell monolayer was examined. The OA fraction was prepared by filtering the aqueous extract of each tissue through an ion-exchange cartridge (Bond Elut C18). In the presence of OA fractions of liver and kidney extracts, substantial increase in APC was observed for tributylmethylammonium (TBuMA, Mw 200) and berberine (Mw 335), but not for triethylmethylammonium (TEMA, Mw 116) and tetraethylammonium (TEA, Mw 130). Because only QAs with higher Mw than a threshold (i.e., > 200) are known to form lipophilic ion-pair complexes with certain organic anions (e.g., bile salts such as taurodeoxycholate), above results are consistent with the hypothesis that only larger Mw QAs form lipophilic ion-pair complexes with endogenous organic anionic components of the liver and kidney extracts. Considering the comparable effect between the liver and kidney extracts on the APC of TBuMA regardless of far less (1/5) content of bile salts in the kidney extract, OAs other than bile salts in the kidney appear to contribute to the formation of lipophilic ion-pair complexes. Most interestingly, the secretory (i.e., basolateral to apical direction) transport of TBuMA and berberine across the LLC-PK1 cell monolayer was decreased by the cis-presence of the kidney extract, while remained unchanged for the transport of TEMA and TEA. The kidney extract had no effect on the absorptive (i.e., apical to basolateral direction) transport and cellular (LLC-PK1) accumulation of all of these QAs. Regardless of underlying mechanisms,it is notable that OA components of liver and kidney extracts influence the APC and secretory transport of QAs with Mw >200.

Decreased Secretory Transport of a Quarternary Ammonium, TBuMA, across LLC-PK1 Cells by the Anionic Kidney Extract

Won-Sik Shim,최민구,김인화,Tae-Sik Kwon,송임숙,Liwei Han,Dae-Duk Kim,정석재,심창구 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.5

The effect of organic anionic (OA) fractions of various rat organ tissues on the apparent partition coefficients (APC) of quarternary ammoniums (QAs) between n-octanol and phosphate buffer (pH 7.4) and QAs transport across the LLC-PK1 cell monolayer was examined. The OA fraction was prepared by filtering the aqueous extract of each tissue through an ion-exchange cartridge (Bond Elut C18). In the presence of OA fractions of liver and kidney extracts, substantial increase in APC was observed for tributylmethylammonium (TBuMA, Mw 200) and berberine (Mw 335), but not for triethylmethylammonium (TEMA, Mw 116) and tetraethylammonium (TEA, Mw 130). Because only QAs with higher Mw than a threshold (i.e., > 200) are known to form lipophilic ion-pair complexes with certain organic anions (e.g., bile salts such as taurodeoxycholate), above results are consistent with the hypothesis that only larger Mw QAs form lipophilic ion-pair complexes with endogenous organic anionic components of the liver and kidney extracts. Considering the comparable effect between the liver and kidney extracts on the APC of TBuMA regardless of far less (1/5) content of bile salts in the kidney extract, OAs other than bile salts in the kidney appear to contribute to the formation of lipophilic ion-pair complexes. Most interestingly, the secretory (i.e., basolateral to apical direction) transport of TBuMA and berberine across the LLC-PK1 cell monolayer was decreased by the cis-presence of the kidney extract, while remained unchanged for the transport of TEMA and TEA. The kidney extract had no effect on the absorptive (i.e., apical to basolateral direction) transport and cellular (LLC-PK1) accumulation of all of these QAs. Regardless of underlying mechanisms, it is notable that OA components of liver and kidney extracts influence the APC and secretory transport of QAs with Mw >200.