scholarly journals The Role of NF-kB in the Downregulation of Organic Cation Transporter 2 Expression and Renal Cation Secretion in Kidney Disease

2022 ◽  
Vol 8 ◽  
Author(s):  
Chao Han ◽  
Juan Zheng ◽  
Fengyi Wang ◽  
Qingyang Lu ◽  
Qingfa Chen ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Organic Cation ◽  
Rat Kidney ◽  
Basolateral Membrane ◽  
Kidney Injury ◽  
Organic Cation Transporter ◽  
Tubular Secretion ◽  
Gene Reporter Assay ◽  
Organic Cation Transporter 2

Organic cation transporter 2 (OCT2), encoded by the SLC22A2 gene, is the main cation transporter on the basolateral membrane of proximal tubular cells. OCT2 facilitates the entry step of the vectorial transport of most cations from the peritubular space into the urine. OCT2 downregulation in kidney disease models is apparent, yet not clear from a mechanistic vantage point. The aim of this study was to explore the role of inflammation, a common thread in kidney disease, and NF-kB in OCT2 modulation and tubular secretion. Among the OCTs, OCT2 was found consistently downregulated in the kidney of rats with chronic kidney disease (CKD) or acute kidney injury (AKI) and in patients diagnosed with CKD, and it was associated with the upregulation of TNFα renal expression. Exposure to TNFα reduced the expression and function of OCT2 in primary renal proximal tubule epithelial cells (RPTEC). Silencing or pharmacological inhibition of NF-kB rescued the expression of OCT2 in the presence of TNFα, indicating that OCT2 repression was NF-kB-dependent. In silico prediction coupled to gene reporter assay demonstrated the presence of at least one functional NF-kB cis-element upstream the transcription starting site of the SLC22A2 gene. Acute inflammation triggered by lipopolysaccharide injection induced TNFα expression and the downregulation of OCT2 in rat kidney. The inflammation did reduce the active secretion of the cation Rhodamine 123, with no impairment of the glomerular filtration. In conclusion, the NF-kB pathway plays a major role in the transcriptional regulation of OCT2 and, in turn, in the overall renal secretory capacity.

Wedelolactone protects against cisplatin-induced nephrotoxicity in mice via inhibition of organic cation transporter 2

2021 ◽  
pp. 096032712110479
Author(s):  
Guangju Wang ◽  
Yajuan Bi ◽  
Hui Xiong ◽  
Tongwei Bo ◽  
Lifeng Han ◽  
...  
Keyword(s):  
Natural Compound ◽  
Organic Cation ◽  
Kidney Injury ◽  
Organic Cation Transporter ◽  
Competitive Inhibitor ◽  
Hek293 Cells ◽  
Cytotoxicity Studies ◽  
Organic Cation Transporter 2 ◽  
Uptake Assay ◽  
Noncompetitive Inhibitor

The balance of cisplatin uptake and efflux, mediated mainly by organic cation transporter 2 (OCT2) and multidrug and toxin extrusion 1 (MATE1), respectively, determines the renal accumulation and nephrotoxicity of cisplatin. Using transporter-mediated cellular uptake assay, we identified wedelolactone (WEL), a medicinal plant-derived natural compound, is a competitive inhibitor of OCT2 and a noncompetitive inhibitor of MATE1. Wedelolactone showed a selectivity to inhibit OCT2 rather than MATE1. Cytotoxicity studies revealed that wedelolactone alleviated cisplatin-induced cytotoxicity in OCT2-overexpressing HEK293 cells, whereas it did not alter the cytotoxicity of cisplatin in various cancer cell lines. Additionally, wedelolactone altered cisplatin pharmacokinetics, reduced kidney accumulation of cisplatin, and ameliorated cisplatin-induced acute kidney injury in the Institute of Cancer Research mice. In conclusion, these findings suggest a translational potential of WEL as a natural therapy for preventing cisplatin-induced nephrotoxicity and highlight the need for drug–drug interaction investigations of WEL with other treatments which are substrates of OCT2 and/or MATE1.

scholarly journals Renal secretion of hydrochlorothiazide involves organic anion transporter 1/3, organic cation transporter 2, and multidrug and toxin extrusion protein 2-K

2019 ◽  
Vol 317 (4) ◽  
pp. F805-F814
Author(s):  
Jia Yin ◽  
David J. Wagner ◽  
Bhagwat Prasad ◽  
Nina Isoherranen ◽  
Kenneth E. Thummel ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Organic Cation ◽  
Organic Anion ◽  
Organic Cation Transporter ◽  
Tubular Secretion ◽  
Organic Anion Transporter ◽  
Anion Transporters ◽  
Anion Transporter ◽  
Organic Cation Transporter 2 ◽  
Toxin Extrusion

Hydrochlorothiazide (HCTZ) is the most widely used thiazide diuretic for the treatment of hypertension either alone or in combination with other antihypertensives. HCTZ is mainly cleared by the kidney via tubular secretion, but the underlying molecular mechanisms are unclear. Using cells stably expressing major renal organic anion and cation transporters [human organic anion transporter 1 (hOAT1), human organic anion transporter 3 (hOAT3), human organic cation transporter 2 (hOCT2), human multidrug and toxin extrusion 1 (hMATE1), and human multidrug and toxin extrusion 2-K (hMATE2-K)], we found that HCTZ interacted with both organic cation and anion transporters. Uptake experiments further showed that HCTZ is transported by hOAT1, hOAT3, hOCT2, and hMATE2-K but not by hMATE1. Detailed kinetic analysis coupled with quantification of membrane transporter proteins by targeted proteomics revealed that HCTZ is an excellent substrate for hOAT1 and hOAT3. The apparent affinities ( Km) for hOAT1 and hOAT3 were 112 ± 8 and 134 ± 13 μM, respectively, and the calculated turnover numbers ( kcat) were 2.48 and 0.79 s−1, respectively. On the other hand, hOCT2 and hMATE2-K showed much lower affinity for HCTZ. The calculated transport efficiency ( kcat/ Km) at the single transporter level followed the rank order of hOAT1> hOAT3 > hOCT2 and hMATE2-K, suggesting a major role of organic anion transporters in tubular secretion of HCTZ. In vitro inhibition experiments further suggested that HCTZ is not a clinically relevant inhibitor for hOAT1 or hOAT3. However, strong in vivo inhibitors of hOAT1/3 may alter renal secretion of HCTZ. Together, our study elucidated the molecular mechanisms underlying renal handling of HCTZ and revealed potential pathways involved in the disposition and drug-drug interactions for this important antihypertensive drug in the kidney.

scholarly journals O32 Ontogeny of human kidney OCT2 expression across the paediatric age range

2019 ◽  
Vol 104 (6) ◽  
pp. e14.2-e14
Author(s):  
N Smeets ◽  
B van Groen ◽  
J Pertijs ◽  
M Wilmer ◽  
B Smeets ◽  
...  
Keyword(s):  
Organic Cation ◽  
Basolateral Membrane ◽  
Age Groups ◽  
Kidney Tissue ◽  
Human Kidney ◽  
Organic Cation Transporter ◽  
Age Related ◽  
Paediatric Age ◽  
Organic Cation Transporter 2 ◽  
Related Pattern

BackgroundIn adults, the organic cation transporter 2 (protein name OCT2, gene name SLC22A2) is localised in the kidney proximal tubules where it mediates organic cation secretion. Hence, the transporter plays a role in the disposition and excretion of several drugs and drug-drug interactions. To better understand the disposition of OCT2 substrate drugs in children, we studied OCT2 localisation and expression in paediatric kidney tissue.MethodsThe expression of OCT2 was visualised in tissue using immunohistochemical staining. Tissues were derived post-mortem from children aged 0 -14 years. Gestational age varied between 24 and 40 weeks. Intensity of the staining at the basolateral membrane was scored by two individual observers using three categories; negative, detectible and high. Agreement between two observers was determined using Cohen’s kappa.Results44 kidney samples (n=17 neonates, n=17 infants, n=7 children, n=3 adolescent) were analysed and scored. There was substantial agreement between two judgements with a kappa of 0.773 (p< 0.005). No age related pattern was observed in the expression of OCT2. Even in the youngest age group, the expression of OCT2 was clearly visible.ConclusionThe kidney expression of OCT2 did not show an age-related pattern. In all age groups, expression levels were similar and OCT2 was properly localised at the basolateral membrane. These findings suggest that, with increasing age, OCT2 will not influence the renal excretion of its substrates.Disclosure(s)Nothing to disclose

Pharmacokinetic study of clofarabine: Oral bioavailability and the effect of cimetidine on renal clearance.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e13074-e13074
Author(s):  
Matthew Charles Foster ◽  
Parag Kumar ◽  
Christine Marie Walko ◽  
Anastasia Ivanova ◽  
Reginald Ewesuedo ◽  
...  
Keyword(s):  
Renal Clearance ◽  
Basolateral Membrane ◽  
Area Under The Curve ◽  
Organic Cation Transporter ◽  
Tubular Secretion ◽  
Time Data ◽  
Geometric Means ◽  
Human Trial ◽  
Organic Cation Transporter 2 ◽  
Renal Tubular

e13074 Background: Clofarabine (CLO) is a purine analog with activity in myeloid neoplasms. Its oral dosing has been based on an estimated bioavailability (F) of 49% from uncontrolled trials. Animal models suggest that CLO renal clearance (CL) may be impaired in the presence of inhibitors of organic cation transporter-2 (OCT2), which mediates transport across the renal tubular basolateral membrane. We conducted a pharmacokinetic (PK) study of CLO to determine F, and examine the effect of the OCT2 inhibitor, cimetidine (CIM) on intravenous (IV) CLO. Methods: Patients had: 1) untreated AML ≥ 60 years of age unsuited for standard induction, 2) relapsed or refractory AML, or 3) MDS after failure of ≥ 1 prior regimen. Treatment was: CLO 15 mg/m2 IV day 1, CLO 30 mg/m2 orally (PO) day 3, CLO 15 mg/m2 IV day 5 preceded by two doses of oral CIM, and CLO 30 mg/m2 PO on days 6 and 7. PK studies were obtained after CLO dosing on days 1, 3 and 5. For each dose, CLO plasma concentration was determined, and concentration-time data was analyzed by non-compartmental methods. F was determined for each patient. The geometric means of area under the curve (AUC), 0-∞, and CL for IV CLO administered after CIM doses were compared with AUC and CL for IV CLO administered without CIM. Results: Interim data for the first ten treated patients, with comparisons of PK parameters are shown in the table below. Conclusions: Using patients as their own controls, F of CLO is higher than previously estimated. AUC of CLO is increased and CL is decreased in the presence of CIM, likely owing to inhibition of OCT2-mediated renal tubular secretion. This study is the first human trial to suggest that CLO CL may be impaired in the presence of OCT2 inhibitors, such as cimetidine, trimethoprim, verapamil and nicotine. [Table: see text]

Key role of organic cation transporter 2 for the nephrotoxicity effect of triptolide in rheumatoid arthritis

2019 ◽  
Vol 77 ◽  
pp. 105959 ◽  
Author(s):  
Qingqing Shen ◽  
Jingjing Wang ◽  
Ziqiao Yuan ◽  
Zhenzhou Jiang ◽  
Ting Shu ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Organic Cation ◽  
Organic Cation Transporter ◽  
Organic Cation Transporter 2

scholarly journals The role of organic cation transporter 2 inhibitor cimetidine, experimental diabetes mellitus and metformin on gabapentin pharmacokinetics in rats

Life Sciences ◽  
2018 ◽  
Vol 200 ◽  
pp. 63-68 ◽  
Author(s):  
Jhohann Richard de Lima Benzi ◽  
Priscila Akemi Yamamoto ◽  
Jessica Hanna Stevens ◽  
Amanda Martins Baviera ◽  
Natália Valadares de Moraes
Keyword(s):  
Diabetes Mellitus ◽  
Organic Cation ◽  
Experimental Diabetes ◽  
Organic Cation Transporter ◽  
Experimental Diabetes Mellitus ◽  
Organic Cation Transporter 2 ◽  
Pharmacokinetics In Rats

scholarly journals Properties of Transport Mediated by the Human Organic Cation Transporter 2 Studied in a Polarized Three-Dimensional Epithelial Cell Culture Model

2021 ◽  
Vol 22 (17) ◽  
pp. 9658
Author(s):  
Tim N. Koepp ◽  
Alexander Tokaj ◽  
Pavel I. Nedvetsky ◽  
Ana Carolina Conchon Costa ◽  
Beatrice Snieder ◽  
...  
Keyword(s):  
Organic Cation ◽  
Basolateral Membrane ◽  
Three Dimensional ◽  
Organic Cation Transporter ◽  
Organic Cations ◽  
Membrane Domain ◽  
Cell Culture Model ◽  
Hek Cells ◽  
Culture Model ◽  
Organic Cation Transporter 2

The renal secretory clearance for organic cations (neurotransmitters, metabolism products and drugs) is mediated by transporters specifically expressed in the basolateral and apical plasma membrane domains of proximal tubule cells. Here, human organic cation transporter 2 (hOCT2) is the main transporter for organic cations in the basolateral membrane domain. In this study, we stably expressed hOCT2 in Madin-Darby Canine Kidney (MDCK) cells and cultivated these cells in the presence of an extracellular matrix to obtain three-dimensional (3D) structures (cysts). The transport properties of hOCT2 expressed in MDCK cysts were compared with those measured using human embryonic kidney cells (HEK293) stably transfected with hOCT2 (hOCT2-HEK cells). In the MDCK cysts, hOCT2 was expressed in the basolateral membrane domain and showed a significant uptake of the fluorescent organic cation 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP+) with an affinity (Km) of 3.6 ± 1.2 µM, similar to what was measured in the hOCT2-HEK cells (Km = 3.1 ± 0.2 µM). ASP+ uptake was inhibited by tetraethylammonium (TEA+), tetrapentylammonium (TPA+), metformin and baricitinib both in the hOCT2-HEK cells and the hOCT2- MDCK cysts, even though the apparent affinities of TEA+ and baricitinib were dependent on the expression system. Then, hOCT2 was subjected to the same rapid regulation by inhibition of p56lck tyrosine kinase or calmodulin in the hOCT2-HEK cells and hOCT2- MDCK cysts. However, inhibition of casein kinase II regulated only activity of hOCT2 expressed in MDCK cysts and not in HEK cells. Taken together, these results suggest that the 3D cell culture model is a suitable tool for the functional analysis of hOCT2 transport properties, depending on cell polarization.

scholarly journals Reduced Hepatic Uptake and Intestinal Excretion of Organic Cations in Mice with a Targeted Disruption of the Organic Cation Transporter 1 (Oct1 [Slc22a1]) Gene

2001 ◽  
Vol 21 (16) ◽  
pp. 5471-5477 ◽  
Author(s):  
Johan W. Jonker ◽  
Els Wagenaar ◽  
Carla A. A. M. Mol ◽  
Marije Buitelaar ◽  
Hermann Koepsell ◽  
...  
Keyword(s):  
Organic Cation ◽  
Basolateral Membrane ◽  
Organic Cation Transporter ◽  
Hepatic Uptake ◽  
Organic Cations ◽  
Wild Type ◽  
Targeted Disruption ◽  
Intestinal Excretion ◽  
Organic Cation Transporter 1

ABSTRACT The polyspecific organic cation transporter 1 (OCT1 [SLC22A1]) mediates facilitated transport of small (hydrophilic) organic cations. OCT1 is localized at the basolateral membrane of epithelial cells in the liver, kidney, and intestine and could therefore be involved in the elimination of endogenous amines and xenobiotics via these organs. To investigate the pharmacologic and physiologic role of this transport protein, we generated Oct1 knockout (Oct1 −/−) mice.Oct1 −/− mice appeared to be viable, healthy, and fertile and displayed no obvious phenotypic abnormalities. The role of Oct1 in the pharmacology of substrate drugs was studied by comparing the distribution and excretion of the model substrate tetraethylammonium (TEA) after intravenous administration to wild-type and Oct1 −/− mice. InOct1 −/− mice, accumulation of TEA in liver was four to sixfold lower than in wild-type mice, whereas direct intestinal excretion of TEA was reduced about twofold. Excretion of TEA into urine over 1 h was 53% of the dose in wild-type mice, compared to 80% in knockout mice, probably because inOct1 −/− mice less TEA accumulates in the liver and thus more is available for rapid excretion by the kidney. In addition, we found that absence of Oct1 leads to decreased liver accumulation of the anticancer drug metaiodobenzylguanidine and the neurotoxin 1-methyl-4-phenylpyridium. In conclusion, our data show that Oct1 plays an important role in the uptake of organic cations into the liver and in their direct excretion into the lumen of the small intestine.

Sign in / Sign up

Export Citation Format

Share Document