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

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.

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 EFFECTS OF CURCUMIN AND NANOCURCUMIN ON CISPLATIN-INDUCED NEPHROTOXICITY IN RAT: COPPER TRANSPORTER 1 AND ORGANIC CATION TRANSPORTER 2 AS DRUG TRANSPORTERS

2018 ◽  
Vol 10 (1) ◽  
pp. 172
Author(s):  
Deliana Nur Ihsani Rahmi ◽  
Melva Louisa ◽  
Vivian Soetikno
Keyword(s):  
Single Dose ◽  
Organic Cation ◽  
Rat Kidney ◽  
Kidney Tissue ◽  
Organic Cation Transporter ◽  
Copper Transporter ◽  
Renal Tubular Cells ◽  
Organic Cation Transporter 2 ◽  
Renal Tubular ◽  
Copper Transporter 1

Objective: This study aimed to investigate the efficacy of curcumin (CMN) and nanocurcumin (NC) at preventing cisplatin (CDPP)-inducednephrotoxicity.Methods: Two membrane transporters, copper transporter 1 (CTR1) and organic cation transporter 2 (OCT2), have been identified involved in activeaccumulation of CDPP into renal tubular cells. We analyzed OCT2 transcription levels in rat kidney tissue and determined whether renoprotectivemechanism of CMN involves CTR1. Rats were randomly divided into five groups: (1) Control, (2) CDPP (7 mg/kg as single dose (i.p.), (3) CDPP+CMN(7 mg/kg CDPP as a single dose, i.p.+100 mg/kg/day of CMN), (4) CDPP+50 mg NC (7 mg/kg CDPP as single dose, i.p.+50 mg/kg/day NC), and(5) CDPP+100 mg NC (7 mg/kg CDPP as single dose, i.p.+100 mg/kg/day NC). Quantitative reverse transcription-polymerase chain reaction wasperformed to calculate relative expression of CTR1 and OCT2 genes in rat kidney.Results: Expression of CTR1 was unassociated with administration of CMN or NC, indicating CTR1 is uninvolved in renoprotective mechanism of CMN.The administration of 100 mg/kg/day NC increased expression of OCT2; this increase was higher compared with normal expression levels. This maybe due to another regulatory mechanism from the CMN itself.Conclusion: NC has a better renoprotective effect compared with curcumin, suggested by the increased OCT2 expression on its administration inCDPP-treated rats.

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.

Different Affinities of Inhibitors to the Outwardly and Inwardly Directed Substrate Binding Site of Organic Cation Transporter 2

2003 ◽  
Vol 64 (5) ◽  
pp. 1037-1047 ◽  
Author(s):  
Christopher Volk ◽  
Valentin Gorboulev ◽  
Thomas Budiman ◽  
Georg Nagel ◽  
Hermann Koepsell
Keyword(s):  
Binding Site ◽  
Organic Cation ◽  
Substrate Binding ◽  
Organic Cation Transporter ◽  
Substrate Binding Site ◽  
Organic Cation Transporter 2
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