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1.
Trop Anim Health Prod ; 53(1): 54, 2021 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-33389207

RESUMO

Poultry production contributes significantly to the livelihoods of Ethiopian farmers and to the national economy although it is hampered by different factors, including poultry diseases. There is scarcity of published evidences on the occurrence and impacts of poultry diseases although such evidences are important for policy makers in designing appropriate interventions. A total of 595 households were interviewed and 11 FGDs were conducted to collect data on the occurrence of diseases and the number of dead chickens in the last 12 months. Hence, respiratory diseases, sudden death, and eye-face-head diseases were mentioned in all of the FGDs as the most frequently occurring disease in the districts. Of households interviewed, 86.1% reported poultry disease occurrence in the last 12 months, and gastrointestinal, eye-face-head, and neurological diseases were identified to be the top three ranked diseases of chickens in the districts. Flocks with access to diagnostic services (Adj. OR = 4.16; P = 0.004) and/or access to animal health providers (Adj. OR = 10.50; P = 0.001) were more likely to report disease occurrence. In the studied population, the diseases resulted in deaths of 2219 chickens valued at 352,219.5 Birr (11,740.65 USD) and a mean crude mortality of 31.87%. Female-lead households (mean difference = 5.95%; P = 0.018) and multiple age units present on the farm (mean difference = 20.92%; P = < 0.000) had higher chicken mortality. Similarly, higher mortality was reported in flocks without access to diagnosis (mean difference = 9.97%; P = < 0.000) and vaccination (mean difference = 12.34%; P = < 0.000) services. The high occurrence of disease and mortalities might be explained by a lack of an organized poultry health service delivery system in the country. Therefore, a carefully designed health service delivery system addressing needs of poultry producers, supported by relevant policy and corresponding strategies, is recommended to address the indicated challenges. Moreover, private health providers with well-defined roles need to be engaged to successfully and sustainably solve the poultry disease problems.

2.
Int J Mol Sci ; 21(18)2020 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-32961667

RESUMO

Extrapolation from animal to human data is not always possible, because several essential factors, such as expression level, localization, as well as the substrate selectivity and affinity of relevant transport proteins, can differ between species. In this study, we examined the interactions of drugs and pesticides with the clinically relevant organic cation transporter hOCT1 (SLC22A1) in comparison to the orthologous transporters from mouse and rat. We determined Km-values (73 ± 7, 36 ± 13, and 57 ± 5 µM) of human, mouse and rat OCT1 for the commonly used substrate 1-methyl-4-phenylpyridinium (MPP) and IC50-values of decynium22 (12.1 ± 0.8, 5.3 ± 0.4, and 10.5 ± 0.4 µM). For the first time, we demonstrated the interaction of the cationic fungicides imazalil, azoxystrobin, prochloraz, and propamocarb with human and rodent OCT1. Drugs such as ketoconazole, clonidine, and verapamil showed substantial inhibitory potential to human, mouse, and rat OCT1 activity. A correlation analysis of hOCT1 versus mouse and rat orthologs revealed a strong functional correlation between the three species. In conclusion, this approach shows that transporter interaction data are in many cases transferable between rodents and humans, but potential species differences for other drugs and pesticides could not be excluded, though it is recommendable to perform functional comparisons of human and rodent transporters for new molecular entities.

3.
Front Chem ; 6: 180, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29888219

RESUMO

Cancer treatment with platinum compounds is an important achievement of modern chemotherapy. However, despite the beneficial effects, the clinical impact of these agents is hampered by the development of drug resistance as well as dose-limiting side effects. The efficacy but also side effects of platinum complexes can be mediated by uptake through plasma membrane transporters. In the kidneys, plasma membrane transporters are involved in their secretion into the urine. Renal secretion is accomplished by uptake from the blood into the proximal tubules cells, followed by excretion into the urine. The uptake process is mediated mainly by organic cation transporters (OCT), which are expressed in the basolateral domain of the plasma membrane facing the blood. The excretion of platinum into the urine is mediated by exchange with protons via multidrug and toxin extrusion proteins (MATE) expressed in the apical domain of plasma membrane. Recently, the monofunctional, cationic platinum agent phenanthriplatin, which is able to escape common cellular resistance mechanisms, has been synthesized and investigated. In the present study, the interaction of phenanthriplatin with transporters for organic cations has been evaluated. Phenanthriplatin is a high affinity substrate for OCT2, but has a lower apparent affinity for MATEs. The presence of these transporters increased cytotoxicity of phenanthriplatin. Therefore, phenanthriplatin may be especially effective in the treatment of cancers that express OCTs, such as colon cancer cells. However, the interaction of phenanthriplatin with OCTs suggests that its use as chemotherapeutic agent may be complicated by OCT-mediated toxicity. Unlike cisplatin, phenanthriplatin interacts with high specificity with hMATE1 and hMATE2K in addition to hOCT2. This interaction may facilitate its efflux from the cells and thereby decrease overall efficacy and/or toxicity.

4.
Parasite Epidemiol Control ; 3(1): 13-20, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29774295

RESUMO

Visceral leishmaniasis (VL) is major neglected public health problem in terms of geographical spread and incidence in Ethiopia. Magnitude, public health impact and dynamics of VL were not well studied in Welkait District, Western Tigray, though the area is known for VL. Hence, this study aimed to determine sero-prevalence of human VL and associated risk factors in Welkait as new foci. A cross sectional study design was employed in this study. Two stage stratified random sampling method was used to select study participants. Hence, a total of 329 human study participants were included for serological survey using ITleish and leishmanin skin tests. Semi structured questionnaire was also used to identify VL associated risk factors. Univariate and multivariate logistic regression statistical methods were used to determine the degree of association. The overall sero-prevalence of human VL in the study area was found to be 8.81%. Statistical significant difference in the prevalence of the disease was found among Sub-districts, sex, re-settlement, sleeping outdoor and dog ownership (P < 0.05). Participants who resettled from their original place were found 2 times (AOR = 2.143; 95% CI = 1.02, 14.20) more vulnerable to VL infection. Those who had an experience of sleeping outdoor were found almost 4 times (AOR = 4.29; 95% CI = 1.58, 11.69) more likely to be at risk of acquiring VL infection than those sleep indoor. Furthermore, individuals who owned dogs were 3 times more prone to the VL infection than their counterparts (AOR = 3.37; 95% CI = 1.29, 8.76). Alarming sero-positivity of human VL was recorded from new foci. Hence, it is recommended to improve the VL health services in the study area. The investigation also invites further study on VL dynamics in the study area.

5.
J Pharmacol Exp Ther ; 362(3): 450-458, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28630284

RESUMO

In renal proximal tubule cells, the organic anion transporters 1 and 3 (OAT1 and OAT3) in the basolateral membrane and the multidrug resistance-associated protein 4 (MRP4) in the apical membrane share substrates and co-operate in renal drug secretion. We hypothesized that recently identified MRP4 inhibitors dantrolene, glafenine, nalidixic acid, and prazosin also interact with human OAT1 and/or OAT3 stably transfected in human embryonic kidney 293 cells. These four drugs were tested as possible inhibitors of p-[3H]aminohippurate (PAH) and [14C]glutarate uptake by OAT1, and of [3H]estrone-3-sulfate (ES) uptake by OAT3. In addition, we explored whether these drugs decrease the equilibrium distribution of radiolabeled PAH, glutarate, or ES, an approach intended to indirectly suggest drug/substrate exchange through OAT1 and OAT3. With OAT3, a dose-dependent inhibition of [3H]ES uptake and a downward shift in [3H]ES equilibrium were observed, indicating that all four drugs bind to OAT3 and may possibly be translocated. In contrast, the interaction with OAT1 was more complex. With [14C]glutarate as substrate, all four drugs inhibited uptake but only glafenine and nalidixic acid shifted glutarate equilibrium. Using [3H]PAH as a substrate of OAT1, nalidixic acid inhibited but dantrolene, glafenine, and prazosin stimulated uptake. Nalidixic acid decreased equilibrium content of [3H]PAH, suggesting that it may possibly be exchanged by OAT1. Taken together, OAT1 and OAT3 interact with the MRP4 inhibitors dantrolene, glafenine, nalidixic acid, and prazosin, indicating overlapping specificities. At OAT1, more than one binding site must be assumed to explain substrate and drug-dependent stimulation and inhibition of transport activity.


Assuntos
Dantroleno/metabolismo , Glafenina/metabolismo , Ácido Nalidíxico/metabolismo , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Prazosina/metabolismo , Ligação Competitiva , Técnicas de Cultura de Células , Estrona/análogos & derivados , Estrona/metabolismo , Células HEK293 , Humanos , Taxa de Depuração Metabólica , Proteína 1 Transportadora de Ânions Orgânicos/genética , Transportadores de Ânions Orgânicos Sódio-Independentes/genética , Ligação Proteica , Ensaio Radioligante , Eliminação Renal , Especificidade por Substrato , Transfecção
6.
Pflugers Arch ; 468(11-12): 1909-1918, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27812757

RESUMO

Dantrolene is the only available drug for the treatment of malignant hyperthermia, a life-threatening inborn sensitivity of the ryanodine receptor (RyR1) in skeletal muscles to volatile anesthetics. Dantrolene is metabolized in the liver to 5-OH dantrolene. Both compounds are zwitterions or net negatively charged. Here, we investigated interactions of dantrolene and 5-OH dantrolene with solute carrier (SLC) family members occurring in skeletal muscle cells, hepatocytes, and renal proximal tubule cells. SLC22A8 (organic anion transporter 3, OAT3) was very sensitive to both compounds exhibiting IC50 values of 0.35 ± 0.03 and 1.84 ± 0.34 µM, respectively. These IC50 concentrations are well below the plasma concentration in patients treated with dantrolene (3-28 µM). SLC22A7 (OAT2) was less sensitive to dantrolene and 5-OH dantrolene with IC50 values of 15.6 ± 2.1 and 15.8 ± 3.2 µM, respectively. SLCO1B1 (OATP1B1), SLCO1B3 (OATP1B3), and SLCO2B1 (OATP2B1) mainly interacted with 5-OH dantrolene albeit with higher IC50 values than those observed for OAT2 and OAT3. Dantrolene and 5-OH dantrolene failed to inhibit uptake of 1-methyl-4-phenylpyrimidinium (MPP) by OCT1 and of carnitine by OCTN2. In counter-flow experiments on OAT3, dantrolene and 5-OH dantrolene decreased pre-equilibrated cellular [3H]estrone-3-sulfate (ES) content as did the transported substrates glutarate, furosemide, and bumetanide. With OAT2, dantrolene and 5-OH dantrolene slightly decreased the pre-equilibrated [3H]cGMP content. If no other transporter markedly contributes to uptake or release of ES or cGMP, respectively, these data suggest that OAT3 and OAT2 may be involved in absorption, metabolism, and excretion of dantrolene and its metabolite 5-OH dantrolene.


Assuntos
Dantroleno/farmacologia , Relaxantes Musculares Centrais/farmacologia , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Transporte Biológico , Células HEK293 , Humanos , Ligação Proteica
8.
Am J Physiol Renal Physiol ; 311(1): F227-38, 2016 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-27053689

RESUMO

The initial step in renal secretion of organic anions (OAs) is mediated by transporters in the basolateral membrane (BLM). Contributors to this process are primary active Na(+)-K(+)-ATPase (EC 3.6.3.9), secondary active Na(+)-dicarboxylate cotransporter 3 (NaDC3/SLC13A3), and tertiary active OA transporters (OATs) OAT1/SLC22A6, OAT2/SLC22A7, and OAT3/SLC22A8. In human kidneys, we analyzed the localization of these transporters by immunochemical methods in tissue cryosections and isolated membranes. The specificity of antibodies was validated with human embryonic kidney-293 cells stably transfected with functional OATs. Na(+)-K(+)-ATPase was immunolocalized to the BLM along the entire human nephron. NaDC3-related immunostaining was detected in the BLM of proximal tubules and in the BLM and/or luminal membrane of principal cells in connecting segments and collecting ducts. The thin and thick ascending limbs, macula densa, and distal tubules exhibited no reactivity with the anti-NaDC3 antibody. OAT1-OAT3-related immunostaining in human kidneys was detected only in the BLM of cortical proximal tubules; all three OATs were stained more intensely in S1/S2 segments compared with S3 segment in medullary rays, whereas the S3 segment in the outer stripe remained unstained. Expression of NaDC3, OAT1, OAT2, and OAT3 proteins exhibited considerable interindividual variability in both male and female kidneys, and sex differences in their expression could not be detected. Our experiments provide a side-by-side comparison of basolateral transporters cooperating in renal OA secretion in the human kidney.


Assuntos
Transportadores de Ácidos Dicarboxílicos/metabolismo , Néfrons/metabolismo , Transportadores de Ânions Orgânicos Dependentes de Sódio/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Simportadores/metabolismo , Adulto , Feminino , Células HEK293 , Humanos , Medula Renal/metabolismo , Túbulos Renais Coletores/metabolismo , Túbulos Renais Distais/metabolismo , Masculino , Membranas/metabolismo , Pessoa de Meia-Idade , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Caracteres Sexuais , ATPase Trocadora de Sódio-Potássio/metabolismo
9.
Nephron ; 131(4): 285-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26640952

RESUMO

OBJECTIVE: Many cellular responses to hypoxia are mediated by the transcription factor complex hypoxia-inducible factor (HIF). HIF stability is governed by a family of dioxygenases called HIF prolyl hydroxylases (PHDs). Isoquinolone-derived PHD inhibitors, like 2-(1-chloro-4-hydroxyisoquinoline-3-carboxamido) acetate (ICA), which stabilize the intracellular HIF-α have been suggested as a potentially beneficial therapeutic strategy for the treatment of disorders associated with ischemia. To stabilize HIF-α, ICA has to be taken up into proximal tubule cells (PCTs) across the basolateral membrane by one of the organic anion transporters 1, 2 or 3 (OAT1, OAT2 or OAT3). The release into the urine across the luminal membrane may be mediated by OAT4. METHOD: To demonstrate interaction of ICA with human OAT1, OAT2, OAT3 and OAT4, ICA was tested on these transporters stably transfected in HEK293 cells by using p-aminohippurate (PAH), cGMP and estrone-3-sulfate (ES) as reference substrates, respectively. RESULTS: Uptakes of PAH and ES in OAT1- and OAT3-transfected HEK293 cells were inhibited by ICA with half-maximal inhibition values of 0.29 ± 0.05 and 2.58 ± 0.16 µM, respectively. OAT2 was less sensitive to ICA. Efflux experiments identified ICA as an OAT1 and OAT3 substrate. Preloading OAT4-transfected HEK293 cells with ICA stimulated ES uptake by 18.3 ± 3.8%. CONCLUSION: The uptake of ICA across the basolateral membrane of PCTs occurs mainly by OAT1 and the efflux into the tubular lumen by OAT4.


Assuntos
Estrona/análogos & derivados , Isoquinolinas/farmacocinética , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Inibidores de Prolil-Hidrolase/farmacocinética , Estrona/metabolismo , Células HEK293 , Humanos , Isoquinolinas/farmacologia , Inibidores de Prolil-Hidrolase/farmacologia , Ácido p-Aminoipúrico/metabolismo
10.
Am J Physiol Renal Physiol ; 309(10): F843-51, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26377792

RESUMO

Phylogentically, organic anion transporter (OAT)1 and OAT3 are closely related, whereas OAT2 is more distant. Experiments with human embryonic kidney-293 cells stably transfected with human OAT1, OAT2, or OAT3 were performed to compare selected transport properties. Common to OAT1, OAT2, and OAT3 is their ability to transport cGMP. OAT2 interacted with prostaglandins, and cGMP uptake was inhibited by PGE2 and PGF2α with IC50 values of 40.8 and 12.7 µM, respectively. OAT1 (IC50: 23.7 µM), OAT2 (IC50: 9.5 µM), and OAT3 (IC50: 1.6 µM) were potently inhibited by MK571, an established multidrug resistance protein inhibitor. OAT2-mediated cGMP uptake was not inhibited by short-chain monocarboxylates and, as opposed to OAT1 and OAT3, not by dicarboxylates. Consequently, OAT2 showed no cGMP/glutarate exchange. OAT1 and OAT3 exhibited a pH and a Cl- dependence with higher substrate uptake at acidic pH and lower substrate uptake in the absence of Cl-, respectively. Such pH and Cl- dependencies were not observed with OAT2. Depolarization of membrane potential by high K+ concentrations in the presence of the K+ ionophore valinomycin left cGMP uptake unaffected. In addition to cGMP, OAT2 transported urate and glutamate, but cGMP/glutamate exchange could not be demonstrated. These experiments suggest that OAT2-mediated cGMP uptake does not occur via exchange with monocarboxylates, dicarboxylates, and hydroxyl ions. The counter anion for electroneutral cGMP uptake remains to be identified.


Assuntos
Transporte Biológico/fisiologia , Rim/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Ácido Úrico/metabolismo , Ânions/metabolismo , Células HEK293 , Humanos , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo
11.
Nat Med ; 21(9): 998-1009, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26236991

RESUMO

Kidney fibrosis is marked by an epithelial-to-mesenchymal transition (EMT) of tubular epithelial cells (TECs). Here we find that, during renal fibrosis, TECs acquire a partial EMT program during which they remain associated with their basement membrane and express markers of both epithelial and mesenchymal cells. The functional consequence of the EMT program during fibrotic injury is an arrest in the G2 phase of the cell cycle and lower expression of several solute and solvent transporters in TECs. We also found that transgenic expression of either Twist1 (encoding twist family bHLH transcription factor 1, known as Twist) or Snai1 (encoding snail family zinc finger 1, known as Snail) expression is sufficient to promote prolonged TGF-ß1-induced G2 arrest of TECs, limiting the cells' potential for repair and regeneration. In mouse models of experimentally induced renal fibrosis, conditional deletion of Twist1 or Snai1 in proximal TECs resulted in inhibition of the EMT program and the maintenance of TEC integrity, while also restoring cell proliferation, dedifferentiation-associated repair and regeneration of the kidney parenchyma and attenuating interstitial fibrosis. Thus, inhibition of the EMT program in TECs during chronic renal injury represents a potential anti-fibrosis therapy.


Assuntos
Pontos de Checagem do Ciclo Celular , Transição Epitelial-Mesenquimal , Rim/patologia , Animais , Aquaporina 1/genética , Células Cultivadas , Fibrose , Fase G2 , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Proteína 1 Transportadora de Ânions Orgânicos/genética
12.
Onderstepoort J Vet Res ; 82(1): E1-7, 2015 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-26304167

RESUMO

Skins and hides are perishable resources that can be damaged by parasitic diseases and human error, which result in downgrading or rejection. This study was conducted to identify defect types and to determine their prevalence in pickled sheep and wet blue goat skins and wet blue hides. Each selected skin or hide was examined for defects in natural light and the defects were graded according to established quality criteria in Ethiopian standard manuals. Major defects were captured by digital photography. The major pre-slaughter defects included scratches (64.2%), cockle (ekek) (32.8%), wounds or scars (12.6%), lesions from pox or lumpy skin disease (6.1%), poor substance (5%), branding marks (2.3%) and tick bites (1.5%). The presence of grain scratches in wet blue hides (76.3%) was significantly higher than in pickled sheep (67.2%) and wet blue goat (59.1%) skins. The major slaughter defects included flay cuts or scores, holes, poor pattern and vein marks, with a higher occurrence in wet blue goat skins (28.7%; P < 0.001) than in wet blue hides (22.8%) and pickled sheep skins (11.1%). The most prevalent postslaughter defects were grain cracks (14.9%), hide beetle damage (8%), damage caused by heat or putrefaction (3.7%) and machine-induced defects (0.5%). Grain cracks (27.04%) and hide beetle damage (13.9%) in wet blue goat skins were significantly more common than in wet blue hides and pickled sheep skins. These defects cause depreciation in the value of the hides and skins. Statistically significant (P < 0.001) higher rejection rates were recorded for wet blue hides (82.9%) than for pickled sheep skins (18.3%) and wet blue goat skins (8.5%). Improved animal health service delivery, effective disease control strategies and strong collaboration between stakeholders are suggested to enhance the quality of skins and hides.


Assuntos
Doenças das Cabras/epidemiologia , Doenças dos Ovinos/epidemiologia , Dermatopatias/veterinária , Pele/patologia , Curtume , Animais , Etiópia/epidemiologia , Doenças das Cabras/etiologia , Doenças das Cabras/patologia , Cabras , Ovinos , Doenças dos Ovinos/etiologia , Doenças dos Ovinos/patologia , Dermatopatias/epidemiologia , Dermatopatias/etiologia , Dermatopatias/patologia
13.
Mol Pharm ; 12(8): 2633-41, 2015 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-25751092

RESUMO

Beta-2-adrenergic agonists are first line therapeutics in the treatment of asthma and chronic obstructive pulmonary disease (COPD). Upon inhalation, bronchodilation is achieved after binding to ß2-receptors, which are primarily localized on airway smooth muscle cells. Given that ß2-adrenergic agonists chemically are bases, they carry net positive charge at physiologic pH value in the lungs (i.e., pH 7.4). Here, we studied whether ß2-agonists interact with organic cation transporters (OCT) and whether this interaction exerted an influence on their passage across the respiratory epithelium to their target receptors. [14C]-TEA uptake into proximal (i.e., Calu-3) and distal (i.e., A549 and NCI-H441) lung epithelial cells was significantly reduced in the presence of salbutamol sulfate, formoterol fumarate, and salmeterol xinafoate in vitro. Expression of all five members of the OCT/N family has been confirmed in human pulmonary epithelial cells in situ and in vitro, which makes the identification of the transporter(s) responsible for the ß2-agonist interaction challenging. Thus, additional experiments were carried out in HEK-293 cells transfected with hOCT1-3. The most pronounced inhibition of organic cation uptake by ß2-agonists was observed in hOCT1 overexpressing HEK-293 cells. hOCT3 transfected HEK-293 cells were affected to a lesser extent, and in hOCT2 transfectants only marginal inhibition of organic cation uptake by ß2-agonists was observed. Bidirectional transport studies across confluent NCI-H441 cell monolayers revealed a net absorptive transport of [3H]-salbutamol, which was sensitive to inhibition by the OCT1 modulator, verapamil. Accordingly, salbutamol uptake into hOCT1 overexpressing HEK-293 cells was time- and concentration-dependent and could be completely blocked by decynium-22. Taken together, our data suggest that ß2-agonists are specific substrates and inhibitors of OCT1 in human respiratory epithelial cells and that this transporter might play a role in the pulmonary disposition of drugs of this class.


Assuntos
Agonistas de Receptores Adrenérgicos beta 2/metabolismo , Agonistas de Receptores Adrenérgicos beta 2/farmacologia , Transportador 1 de Cátions Orgânicos/antagonistas & inibidores , Transportador 1 de Cátions Orgânicos/metabolismo , Agonistas de Receptores Adrenérgicos beta 2/farmacocinética , Albuterol/metabolismo , Albuterol/farmacocinética , Albuterol/farmacologia , Transporte Biológico , Células Cultivadas , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Fumarato de Formoterol/metabolismo , Fumarato de Formoterol/farmacocinética , Fumarato de Formoterol/farmacologia , Células HEK293 , Humanos , Transportador 1 de Cátions Orgânicos/genética , Mucosa Respiratória/efeitos dos fármacos , Mucosa Respiratória/metabolismo , Absorção pelo Trato Respiratório , Xinafoato de Salmeterol/metabolismo , Xinafoato de Salmeterol/farmacocinética , Xinafoato de Salmeterol/farmacologia , Transfecção
14.
Eur J Med Chem ; 92: 723-31, 2015 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-25618019

RESUMO

Antineoplastic compounds are used in the treatment of a variety of cancers. The effectiveness of an antineoplastic compound to exert its activity is largely dependent on transport proteins involved in the entry of the compound into the cells, and those which drive it out of the cell. Organic anion transporting polypeptide 1B1 (OATP1B1) and organic anion transporting polypeptide 1B3 (OATP1B3), belonging to the SLCO family of proteins, are specifically expressed in the sinusoidal membranes of the liver, and are known to interact with a variety of drugs. The present study deals with the interaction of these proteins with antineoplastic compounds routinely used in cancer chemotherapy. The proteins OATP1B1 and OATP1B3 were functionally characterized in stably transfected human embryonic kidney cells using [(3)H] labeled estrone 3-sulfate and [(3)H] labeled cholecystokinin octapeptide (CCK-8) as substrates, respectively. Substrate uptake experiments performed in the presence of antineoplastic compounds showed that vinblastine and paclitaxel strongly interacted with the OATP1B1 with Ki values of 10.2 µM and 0.84 µM, respectively. OATP1B3 showed highly significant interactions with a variety of antineoplastic compounds including chlorambucil, mitoxantrone, vinblastine, vincristine, paclitaxel and etoposide, with Ki values of 40.6 µM, 3.2 µM, 15.9 µM, 30.6 µM, 1.8 µM and 13.5 µM, respectively. We report several novel interactions of the transporter proteins OATP1B1 and OATP1B3 highlighting the need to investigate their role in drug-drug interactions and cancer chemotherapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Peptídeos/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/síntese química , Protocolos de Quimioterapia Combinada Antineoplásica/química , Linhagem Celular , Humanos , Transportador 1 de Ânion Orgânico Específico do Fígado , Estrutura Molecular , Transportadores de Ânions Orgânicos/química , Transportadores de Ânions Orgânicos Sódio-Independentes/química , Peptídeos/química , Membro 1B3 da Família de Transportadores de Ânion Orgânico Carreador de Soluto
15.
Brain Struct Funct ; 220(1): 193-203, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24129767

RESUMO

Sulforhodamine 101 (SR101) is widely used for astrocyte identification, though the labeling mechanism remains unknown and the efficacy of labeling in different brain regions is heterogeneous. By combining region-specific isolation of astrocytes followed by transcriptome analysis, two-photon excitation microscopy, and mouse genetics, we identified the thyroid hormone transporter OATP1C1 as the SR101-uptake transporter in hippocampus and cortex.


Assuntos
Astrócitos/metabolismo , Corantes , Hipocampo/citologia , Proteínas de Transporte de Cátions Orgânicos/metabolismo , Rodaminas , Animais , Animais Recém-Nascidos , Córtex Cerebral/citologia , Biologia Computacional , Eletrólitos/líquido cefalorraquidiano , Feminino , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Técnicas In Vitro , Masculino , Camundongos , Camundongos Transgênicos , Optogenética , Proteínas de Transporte de Cátions Orgânicos/genética
16.
Pharmacol Res ; 91: 78-87, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25481222

RESUMO

The ability of an antineoplastic drug to exert its cytostatic effect depends largely on the balance between its uptake into and extrusion from the cancer cells. ATP driven efflux transporter proteins drive the export of antineoplastic drugs and play a pivotal role in the development of chemoresistance. As regards uptake transporters, comparably less is known on their impact in drug action. In the current study, we characterized the interactions of two uptake transporter proteins, expressed mainly in the liver; the organic anion transporter 2 (OAT2, encoded by the SLC22A7 gene) and the sodium taurocholate cotransporting polypeptide (NTCP, encoded by the SLC10A1 gene), stably transfected in human embryonic kidney cells, with some antineoplastic agents that are routinely being used in cancer chemotherapy. Whereas NTCP did not show any strong interactions with the cytostatics tested, we observed a very strong inhibition of OAT2 mediated [(3)H] cGMP uptake in the presence of bendamustine, irinotecan and paclitaxel. The Ki values of OAT2 for bendamustine, irinotecan and paclitaxel were determined to be 43.3±4.33µM, 26.4±2.34µM and 10.4±0.45µM, respectively. Incubation of bendamustine with OAT2 expressing cells increased the caspase-3 activity, and this increase was inhibited by simultaneous incubation with bendamustine and probenecid, a well-known inhibitor of OATs, suggesting that bendamustine is a substrate of OAT2. A higher accumulation of irinotecan was observed in OAT2 expressing cells compared to control pcDNA cells by HPLC analysis of cell lysates. The accumulation was diminished in the presence of cGMP, the substrate we used to functionally characterize OAT2, suggesting specificity of this uptake and the fact that OAT2 mediates uptake of irinotecan.


Assuntos
Antineoplásicos/farmacologia , Transportadores de Ânions Orgânicos Dependentes de Sódio/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Simportadores/metabolismo , Apoptose/efeitos dos fármacos , Cloridrato de Bendamustina , Transporte Biológico , Camptotecina/análogos & derivados , Camptotecina/farmacologia , GMP Cíclico/metabolismo , Estrona/análogos & derivados , Estrona/metabolismo , Células HEK293 , Humanos , Irinotecano , Compostos de Mostarda Nitrogenada/farmacologia , Paclitaxel/farmacologia
17.
Am J Physiol Renal Physiol ; 308(4): F330-8, 2015 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-25477469

RESUMO

Chronic lymphatic leukemia (CLL) is often associated with nephritic syndrome. Effective treatment of CLL by chlorambucil and bendamustine leads to the restoration of renal function. In this contribution, we sought to elucidate the impact of organic anion transporters (OATs) on the uptake of bendamustine and chlorambucil as a probable reason for the superior efficacy of bendamustine over chlorambucil in the treatment of CLL. We examined the effects of structural analogs of p-aminohippurate (PAH), melphalan, chlorambucil, and bendamustine, on OAT1-mediated [(3)H]PAH uptake and OAT3- and OAT4-mediated [(3)H]estrone sulfate (ES) uptake in stably transfected human embryonic kidney-293 cells. Melphalan had no significant inhibitory effect on any OAT, whereas chlorambucil reduced OAT1-, OAT3-, and OAT4-mediated uptake of PAH or ES down to 14.6%, 16.3%, and 66.0% of control, respectively. Bendamustine inhibited only OAT3-mediated ES uptake, which was reduced down to 14.3% of control cells, suggesting that it interacts exclusively with OAT3. The IC50 value for OAT3 was calculated to be 0.8 µM. Real-time PCR experiments demonstrated a high expression of OAT3 in lymphoma cell lines as well as primary CLL cells. OAT3-mediated accumulation of bendamustine was associated with reduced cell proliferation and an increased rate of apoptosis. We conclude that the high efficacy of bendamustine in treating CLL might be partly contributed to the expression of OAT3 in lymphoma cells and the high affinity of bendamustine for this transporter.


Assuntos
Antineoplásicos Alquilantes/farmacologia , Leucemia Linfocítica Crônica de Células B/metabolismo , Linfoma de Células T/metabolismo , Compostos de Mostarda Nitrogenada/farmacologia , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Antineoplásicos Alquilantes/metabolismo , Apoptose/efeitos dos fármacos , Cloridrato de Bendamustina , Proliferação de Células/efeitos dos fármacos , Clorambucila/metabolismo , Clorambucila/farmacologia , Relação Dose-Resposta a Droga , Estrona/análogos & derivados , Estrona/metabolismo , Células HEK293 , Humanos , Células Jurkat , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/patologia , Linfoma de Células T/genética , Linfoma de Células T/patologia , Melfalan/metabolismo , Melfalan/farmacologia , Compostos de Mostarda Nitrogenada/metabolismo , Proteína 1 Transportadora de Ânions Orgânicos/antagonistas & inibidores , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/antagonistas & inibidores , Transportadores de Ânions Orgânicos Sódio-Independentes/genética , Transfecção , Células Tumorais Cultivadas , Ácido p-Aminoipúrico/metabolismo
18.
Am J Physiol Renal Physiol ; 307(12): F1373-9, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25354943

RESUMO

Inborn defects in N-acetylglutamate (NAG) synthase (NAGS) cause a reduction of NAG, an essential cofactor for the initiation of the urea cycle. As a consequence, blood ammonium concentrations are elevated, leading to severe neurological disorders. The orphan drug N-carbamoylglutamate (NCG; Carbaglu), efficiently overcomes NAGS deficiency. However, not much is known about the transporters involved in the uptake, distribution, and elimination of the divalent organic anion NCG. Organic anion-transporting polypeptides (OATPs) as well as organic anion transporters (OATs) working in cooperation with sodium dicarboxylate cotransporter 3 (NaDC3) accept a wide variety of structurally unrelated drugs. To test for possible interactions with OATPs and OATs, the impact of NCG on these transporters in stably transfected human embryonic kidney-293 cells was measured. The two-electrode voltage-clamp technique was used to monitor NCG-mediated currents in Xenopus laevis oocytes that expressed NaDC3. Neither OATPs nor OAT2 and OAT3 interacted with NCG, but OAT1 transported NCG. In addition, NCG was identified as a high-affinity substrate of NaDC3. Preincubation of OAT4-transfected human embryonic kidney-293 cells with NCG showed an increased uptake of estrone sulfate, the reference substrate of OAT4, indicating efflux of NCG by OAT4. In summary, NaDC3 and, to a lesser extent, OAT1 are likely to be responsible for the uptake of NCG from the blood. Efflux of NCG across the luminal membrane into the tubular lumen probably occurs by OAT4 completing renal secretion of this drug.


Assuntos
Transportadores de Ácidos Dicarboxílicos/metabolismo , Glutamatos/metabolismo , Túbulos Renais Proximais/metabolismo , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Dependentes de Sódio/metabolismo , Eliminação Renal , Simportadores/metabolismo , Distúrbios Congênitos do Ciclo da Ureia/tratamento farmacológico , Aminoácido N-Acetiltransferase , Animais , Transportadores de Ácidos Dicarboxílicos/genética , Células HEK293 , Humanos , Potenciais da Membrana , Proteína 1 Transportadora de Ânions Orgânicos/genética , Transportadores de Ânions Orgânicos Dependentes de Sódio/genética , Simportadores/genética , Transfecção , Distúrbios Congênitos do Ciclo da Ureia/enzimologia , Xenopus laevis
19.
J Pharm Sci ; 103(10): 3326-34, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25175346

RESUMO

Increased expression of transporters-mediating uptake of antineoplastic drugs could render renal cell carcinoma (RCC) more sensitive to chemotherapy. Here, we studied the effect of hepatocyte nuclear factor 4α (HNF4α) on the expression of selected uptake transporters in RCC lines. Organic cation transporters (OCTs) and organic anion transporters (OATs) mRNA levels in HNF4α-transfected RCCs were measured by real-time PCR. Expression of HNF4α, ß-catenin, N-cadherin, and E-cadherin was detected by immunofluorescence. OCT1, OAT2, and concentrative nucleoside transporter 3 (CNT3) were tested using tritium-labeled substrates and an apoptosis assay. Most RCC did not express uptake transporters in the absence or presence of HNF4α. In RCCNG1 cells, HNF4α-expression increased the chemosensitivity to oxaliplatin and enhanced the accumulation of methyl-4-phenylpyridinium acetate, a model substrate for OCT1. Furthermore, HNF4α enhanced OAT2 mRNA and increased caspase-3 activity upon incubation with a purported OAT2 substrate, 5-fluorouracil (5-FU). However, functional OAT2 protein was not upregulated. CNT3 mRNA was significantly elevated by HNF4α. Inhibition of CNT3-mediated uridine uptake by 5-FU metabolite 5-fluoro-2'-deoxyuridine suggested the involvement of CNT3 in increased caspase-3 activity. Our data suggest that HNF4α increases the expression of OCT1 and CNT3 in RCCNG1 cells, thereby increasing the chemosensitivity of tumor cells to oxaliplatin and 5-FU.


Assuntos
Antineoplásicos/farmacologia , Carcinoma de Células Renais/patologia , Fluoruracila/farmacologia , Fator 4 Nuclear de Hepatócito/fisiologia , Neoplasias Renais/patologia , Proteínas de Membrana Transportadoras/fisiologia , Transportador 1 de Cátions Orgânicos/fisiologia , Compostos Organoplatínicos/farmacologia , Linhagem Celular Tumoral , Humanos , Oxaliplatina , Reação em Cadeia da Polimerase em Tempo Real
20.
J Hered ; 105(1): 82-90, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24285829

RESUMO

Eritrea has one of the northernmost populations of African elephants. Only about 100 elephants persist in the Gash-Barka administrative zone. Elephants in Eritrea have become completely isolated, with no gene flow from other elephant populations. The conservation of Eritrean elephants would benefit from an understanding of their genetic affinities to elephants elsewhere on the continent and the degree to which genetic variation persists in the population. Using dung samples from Eritrean elephants, we examined 18 species-diagnostic single nucleotide polymorphisms in 3 nuclear genes, sequences of mitochondrial HVR1 and ND5, and genotyped 11 microsatellite loci. The sampled Eritrean elephants carried nuclear and mitochondrial DNA markers establishing them as savanna elephants, with closer genetic affinity to Eastern than to North Central savanna elephant populations, and contrary to speculation by some scholars that forest elephants were found in Eritrea. Mitochondrial DNA diversity was relatively low, with 2 haplotypes unique to Eritrea predominating. Microsatellite genotypes could only be determined for a small number of elephants but suggested that the population suffers from low genetic diversity. Conservation efforts should aim to protect Eritrean elephants and their habitat in the short run, with restoration of habitat connectivity and genetic diversity as long-term goals.


Assuntos
DNA Mitocondrial/isolamento & purificação , Elefantes/genética , Variação Genética , Animais , Conservação dos Recursos Naturais , DNA Mitocondrial/genética , Ecossistema , Eritreia , Loci Gênicos , Marcadores Genéticos , Genótipo , Haplótipos , Repetições de Microssatélites , Filogeografia , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Árvores
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