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Ermakov VS, Granados JC, Nigam SK. Remote effects of kidney drug transporter OAT1 on gut microbiome composition and urate homeostasis. JCI Insight 2023; 8:e172341. [PMID: 37937647 PMCID: PMC10721261 DOI: 10.1172/jci.insight.172341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 09/12/2023] [Indexed: 11/09/2023] Open
Abstract
The organic anion transporter OAT1 (SLC22A6, originally identified as NKT) is a multispecific transporter responsible for the elimination by the kidney of small organic anions that derive from the gut microbiome. Many are uremic toxins associated with chronic kidney disease (CKD). OAT1 is among a group of "drug" transporters that act as hubs in a large homeostatic network regulating interorgan and interorganismal communication via small molecules. The Remote Sensing and Signaling Theory predicts that genetic deletion of such a key hub in the network results in compensatory interorganismal communication (e.g., host-gut microbe dynamics). Recent metabolomics data from Oat1-KO mice indicate that some of the most highly affected metabolites derive from bacterial tyrosine, tryptophan, purine, and fatty acid metabolism. Functional metagenomic analysis of fecal 16S amplicon and whole-genome sequencing revealed that loss of OAT1 was impressively associated with microbial pathways regulating production of urate, gut-derived p-cresol, tryptophan derivatives, and fatty acids. Certain changes, such as alterations in gut microbiome urate metabolism, appear compensatory. Thus, Oat1 in the kidney appears to mediate remote interorganismal communication by regulating the gut microbiome composition and metabolic capability. Since OAT1 function in the proximal tubule is substantially affected in CKD, our results may shed light on the associated alterations in gut-microbiome dynamics.
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Affiliation(s)
| | | | - Sanjay K. Nigam
- Department of Pediatrics, and
- Department of Medicine, Division of Nephrology, University of California, San Diego (UCSD), La Jolla, California, USA
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Granados JC, Watrous JD, Long T, Rosenthal SB, Cheng S, Jain M, Nigam SK. Regulation of Human Endogenous Metabolites by Drug Transporters and Drug Metabolizing Enzymes: An Analysis of Targeted SNP-Metabolite Associations. Metabolites 2023; 13:metabo13020171. [PMID: 36837791 PMCID: PMC9958903 DOI: 10.3390/metabo13020171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 01/26/2023] Open
Abstract
Drug transporters and drug-metabolizing enzymes are primarily known for their role in the absorption, distribution, metabolism, and excretion (ADME) of small molecule drugs, but they also play a key role in handling endogenous metabolites. Recent cross-tissue co-expression network analyses have revealed a "Remote Sensing and Signaling Network" of multispecific, oligo-specific, and monospecific transporters and enzymes involved in endogenous metabolism. This includes many proteins from families involved in ADME (e.g., SLC22, SLCO, ABCC, CYP, UGT). Focusing on the gut-liver-kidney axis, we identified the endogenous metabolites potentially regulated by this network of ~1000 proteins by associating SNPs in these genes with the circulating levels of thousands of small, polar, bioactive metabolites, including free fatty acids, eicosanoids, bile acids, and other signaling metabolites that act in part via G-protein coupled receptors (GPCRs), nuclear receptors, and kinases. We identified 77 genomic loci associated with 7236 unique metabolites. This included metabolites that were associated with multiple, distinct loci, indicating coordinated regulation between multiple genes (including drug transporters and drug-metabolizing enzymes) of specific metabolites. We analyzed existing pharmacogenomic data and noted SNPs implicated in endogenous metabolite handling (e.g., rs4149056 in SLCO1B1) also affecting drug ADME. The overall results support the existence of close relationships, via interactions with signaling metabolites, between drug transporters and drug-metabolizing enzymes that are part of the Remote Sensing and Signaling Network, and with GPCRs and nuclear receptors. These analyses highlight the potential for drug-metabolite interactions at the interfaces of the Remote Sensing and Signaling Network and the ADME protein network.
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Affiliation(s)
- Jeffry C. Granados
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Jeramie D. Watrous
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093, USA
| | - Tao Long
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093, USA
| | - Sara Brin Rosenthal
- Center for Computational Biology and Bioinformatics, University of California San Diego, La Jolla, CA 92093, USA
| | - Susan Cheng
- Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Mohit Jain
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093, USA
| | - Sanjay K. Nigam
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
- Correspondence:
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Granados JC, Ermakov V, Maity K, Vera DR, Chang G, Nigam SK. The kidney drug transporter OAT1 regulates gut microbiome-dependent host metabolism. JCI Insight 2023; 8:160437. [PMID: 36692015 PMCID: PMC9977316 DOI: 10.1172/jci.insight.160437] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/30/2022] [Indexed: 01/24/2023] Open
Abstract
Organic anion transporter 1 (OAT1/SLC22A6, NKT) is a multispecific drug transporter in the kidney with numerous substrates, including pharmaceuticals, endogenous metabolites, natural products, and uremic toxins. Here, we show that OAT1 regulates levels of gut microbiome-derived metabolites. We depleted the gut microbiome of Oat1-KO and WT mice and performed metabolomics to analyze the effects of genotype (KO versus WT) and microbiome depletion. OAT1 is an in vivo intermediary between the host and the microbes, with 40 of the 162 metabolites dependent on the gut microbiome also impacted by loss of Oat1. Chemoinformatic analysis revealed that the altered metabolites (e.g., indoxyl sulfate, p-cresol sulfate, deoxycholate) had more ring structures and sulfate groups. This indicates a pathway from gut microbes to liver phase II metabolism, to renal OAT1-mediated transport. The idea that multiple gut-derived metabolites directly interact with OAT1 was confirmed by in vitro transport and magnetic bead binding assays. We show that gut microbiome-derived metabolites dependent on OAT1 are impacted in a chronic kidney disease (CKD) model and human drug-metabolite interactions. Consistent with the Remote Sensing and Signaling Theory, our results support the view that drug transporters (e.g., OAT1, OAT3, OATP1B1, OATP1B3, MRP2, MRP4, ABCG2) play a central role in regulating gut microbe-dependent metabolism, as well as interorganismal communication between the host and microbiome.
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Affiliation(s)
| | | | - Koustav Maity
- Skaggs School of Pharmacy and Pharmaceutical Sciences
| | - David R. Vera
- Department of Radiology,,In Vivo Cancer and Molecular Imaging Program
| | - Geoffrey Chang
- Skaggs School of Pharmacy and Pharmaceutical Sciences,,Department of Pharmacology, School of Medicine
| | - Sanjay K. Nigam
- Department of Pediatrics, and,Department of Medicine (Nephrology), UCSD, La Jolla, California, USA
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Abstract
The coordinated movement of organic anions (e.g., drugs, metabolites, signaling molecules, nutrients, antioxidants, gut microbiome products) between tissues and body fluids depends, in large part, on organic anion transporters (OATs) [solute carrier 22 (SLC22)], organic anion transporting polypeptides (OATPs) [solute carrier organic (SLCO)], and multidrug resistance proteins (MRPs) [ATP-binding cassette, subfamily C (ABCC)]. Depending on the range of substrates, transporters in these families can be considered multispecific, oligospecific, or (relatively) monospecific. Systems biology analyses of these transporters in the context of expression patterns reveal they are hubs in networks involved in interorgan and interorganismal communication. The remote sensing and signaling theory explains how the coordinated functions of drug transporters, drug-metabolizing enzymes, and regulatory proteins play a role in optimizing systemic and local levels of important endogenous small molecules. We focus on the role of OATs, OATPs, and MRPs in endogenous metabolism and how their substrates (e.g., bile acids, short chain fatty acids, urate, uremic toxins) mediate interorgan and interorganismal communication and help maintain and restore homeostasis in healthy and disease states.
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Affiliation(s)
- Sanjay K Nigam
- Department of Pediatrics and Medicine (Nephrology), University of California San Diego, La Jolla, California, USA;
| | - Jeffry C Granados
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
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Granados JC, Falah K, Koo I, Morgan EW, Perdew GH, Patterson AD, Jamshidi N, Nigam SK. AHR is a master regulator of diverse pathways in endogenous metabolism. Sci Rep 2022; 12:16625. [PMID: 36198709 PMCID: PMC9534852 DOI: 10.1038/s41598-022-20572-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 09/15/2022] [Indexed: 11/08/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a transcription factor with roles in detoxification, development, immune response, chronic kidney disease and other syndromes. It regulates the expression of drug transporters and drug metabolizing enzymes in a proposed Remote Sensing and Signaling Network involved in inter-organ communication via metabolites and signaling molecules. Here, we use integrated omics approaches to analyze its contributions to metabolism across multiple scales from the organ to the organelle. Global metabolomics analysis of Ahr-/- mice revealed the role of AHR in the regulation of 290 metabolites involved in many biochemical pathways affecting fatty acids, bile acids, gut microbiome products, antioxidants, choline derivatives, and uremic toxins. Chemoinformatics analysis suggest that AHR plays a role in determining the hydrophobicity of metabolites and perhaps their transporter-mediated movement into and out of tissues. Of known AHR ligands, indolepropionate was the only significantly altered molecule, and it activated AHR in both human and murine cells. To gain a deeper biological understanding of AHR, we employed genome scale metabolic reconstruction to integrate knockout transcriptomics and metabolomics data, which indicated a role for AHR in regulation of organic acids and redox state. Together, the results indicate a central role of AHR in metabolism and signaling between multiple organs and across multiple scales.
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Affiliation(s)
- Jeffry C Granados
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Kian Falah
- Departments of Biology, University of California San Diego, La Jolla, CA, 92093, USA
| | - Imhoi Koo
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Ethan W Morgan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, PA, 16801, USA
| | - Gary H Perdew
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Andrew D Patterson
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Neema Jamshidi
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Sanjay K Nigam
- Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093, USA.
- Department of Medicine (Nephrology), University of California San Diego, La Jolla, CA, 92093, USA.
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Nigam SK, Granados JC. A Biological Basis for Pharmacokinetics: The Remote Sensing and Signaling Theory. Clin Pharmacol Ther 2022; 112:456-460. [PMID: 35598078 PMCID: PMC9398931 DOI: 10.1002/cpt.2634] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 04/30/2022] [Indexed: 12/12/2022]
Affiliation(s)
- Sanjay K. Nigam
- Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093
| | - Jeffry C. Granados
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093
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Granados JC, Bhatnagar V, Nigam SK. Blockade of Organic Anion Transport in Humans After Treatment With the Drug Probenecid Leads to Major Metabolic Alterations in Plasma and Urine. Clin Pharmacol Ther 2022; 112:653-664. [PMID: 35490380 PMCID: PMC9398954 DOI: 10.1002/cpt.2630] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/17/2022] [Indexed: 12/15/2022]
Abstract
Probenecid is used to treat gout and hyperuricemia as well as increase plasma levels of antiviral drugs and antibiotics. In vivo, probenecid mainly inhibits the renal SLC22 organic anion transporters OAT1 (SLC22A6), OAT3 (SLC22A8), and URAT1 (SLC22A12). To understand the endogenous role of these transporters in humans, we administered probenecid to 20 healthy participants and metabolically profiled the plasma and urine before and after dosage. Hundreds of metabolites were significantly altered, indicating numerous drug-metabolite interactions. We focused on potential OAT1 substrates by identifying 97 metabolites that were significantly elevated in the plasma and decreased in the urine, indicating OAT-mediated clearance. These included signaling molecules, antioxidants, and gut microbiome products. In contrast, urate was the only metabolite significantly decreased in the plasma and elevated in the urine, consistent with an effect on renal reuptake by URAT1. Additional support comes from metabolomics analyses of our Oat1 and Oat3 knockout mice, where over 50% of the metabolites that were likely OAT substrates in humans were elevated in the serum of the mice. Fifteen of these compounds were elevated in both knockout mice, whereas six were exclusive to the Oat1 knockout and 4 to the Oat3 knockout. These may be endogenous biomarkers of OAT function. We also propose a probenecid stress test to evaluate kidney proximal tubule organic anion transport function in kidney disease. Consistent with the Remote Sensing and Signaling Theory, the profound changes in metabolite levels following probenecid treatment support the view that SLC22 transporters are hubs in the regulation of systemic human metabolism.
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Affiliation(s)
- Jeffry C. Granados
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093
| | - Vibha Bhatnagar
- Department of Family Medicine, University of California San Diego, La Jolla, CA, 92093
| | - Sanjay K. Nigam
- Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093
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Torres AM, Dnyanmote AV, Granados JC, Nigam SK. Renal and non-renal response of ABC and SLC transporters in chronic kidney disease. Expert Opin Drug Metab Toxicol 2021; 17:515-542. [PMID: 33749483 DOI: 10.1080/17425255.2021.1899159] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION The solute carrier (SLC) and the ATP-binding cassette (ABC) transporter superfamilies play essential roles in the disposition of small molecules (endogenous metabolites, uremic toxins, drugs) in the blood, kidney, liver, intestine, and other organs. In chronic kidney disease (CKD), the loss of renal function is associated with altered function of remote organs. As renal function declines, many molecules accumulate in the plasma. Many studies now support the view that ABC and SLC transporters as well as drug metabolizing enzymes (DMEs) in renal and non-renal tissues are directly or indirectly affected by the presence of various types of uremic toxins, including those derived from the gut microbiome; this can lead to aberrant inter-organ communication. AREAS COVERED Here, the expression, localization and/or function of various SLC and ABC transporters as well as DMEs in the kidney and other organs are discussed in the context of CKD and systemic pathophysiology. EXPERT OPINION According to the Remote Sensing and Signaling Theory (RSST), a transporter and DME-centric network that optimizes local and systemic metabolism maintains homeostasis in the steady state and resets homeostasis following perturbations due to renal dysfunction. The implications of this view for pharmacotherapy of CKD are also discussed.
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Affiliation(s)
- Adriana M Torres
- Pharmacology Area, Faculty of Biochemistry and Pharmaceutical Sciences, National University of Rosario, CONICET, Suipacha 531, S2002LRK Rosario, Argentina
| | - Ankur V Dnyanmote
- Department of Pediatrics, IWK Health Centre - Dalhousie University, 5850 University Ave, Halifax, NS, B3K 6R8, Canada
| | - Jeffry C Granados
- Department of Bioengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0693, USA
| | - Sanjay K Nigam
- Departments of Pediatrics and Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0693, USA
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Granados JC, Nigam AK, Bush KT, Jamshidi N, Nigam SK. A key role for the transporter OAT1 in systemic lipid metabolism. J Biol Chem 2021; 296:100603. [PMID: 33785360 PMCID: PMC8102404 DOI: 10.1016/j.jbc.2021.100603] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/22/2021] [Accepted: 03/26/2021] [Indexed: 01/06/2023] Open
Abstract
Organic anion transporter 1 (OAT1/SLC22A6) is a drug transporter with numerous xenobiotic and endogenous substrates. The Remote Sensing and Signaling Theory suggests that drug transporters with compatible ligand preferences can play a role in “organ crosstalk,” mediating overall organismal communication. Other drug transporters are well known to transport lipids, but surprisingly little is known about the role of OAT1 in lipid metabolism. To explore this subject, we constructed a genome-scale metabolic model using omics data from the Oat1 knockout mouse. The model implicated OAT1 in the regulation of many classes of lipids, including fatty acids, bile acids, and prostaglandins. Accordingly, serum metabolomics of Oat1 knockout mice revealed increased polyunsaturated fatty acids, diacylglycerols, and long-chain fatty acids and decreased ceramides and bile acids when compared with wildtype controls. Some aged knockout mice also displayed increased lipid droplets in the liver when compared with wildtype mice. Chemoinformatics and machine learning analyses of these altered lipids defined molecular properties that form the structural basis for lipid-transporter interactions, including the number of rings, positive charge/volume, and complexity of the lipids. Finally, we obtained targeted serum metabolomics data after short-term treatment of rodents with the OAT-inhibiting drug probenecid to identify potential drug–metabolite interactions. The treatment resulted in alterations in eicosanoids and fatty acids, further supporting our metabolic reconstruction predictions. Consistent with the Remote Sensing and Signaling Theory, the data support a role of OAT1 in systemic lipid metabolism.
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Affiliation(s)
- Jeffry C Granados
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
| | - Anisha K Nigam
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Kevin T Bush
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Neema Jamshidi
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, USA
| | - Sanjay K Nigam
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA; Department of Medicine, University of California San Diego, La Jolla, California, USA.
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Granados JC, Richelle A, Gutierrez JM, Zhang P, Zhang X, Bhatnagar V, Lewis NE, Nigam SK. Coordinate regulation of systemic and kidney tryptophan metabolism by the drug transporters OAT1 and OAT3. J Biol Chem 2021; 296:100575. [PMID: 33757768 PMCID: PMC8102410 DOI: 10.1016/j.jbc.2021.100575] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/09/2021] [Accepted: 03/19/2021] [Indexed: 12/18/2022] Open
Abstract
How organs sense circulating metabolites is a key question. Here, we show that the multispecific organic anion transporters of drugs, OAT1 (SLC22A6 or NKT) and OAT3 (SLC22A8), play a role in organ sensing. Metabolomics analyses of the serum of Oat1 and Oat3 knockout mice revealed changes in tryptophan derivatives involved in metabolism and signaling. Several of these metabolites are derived from the gut microbiome and are implicated as uremic toxins in chronic kidney disease. Direct interaction with the transporters was supported with cell-based transport assays. To assess the impact of the loss of OAT1 or OAT3 function on the kidney, an organ where these uptake transporters are highly expressed, knockout transcriptomic data were mapped onto a “metabolic task”-based computational model that evaluates over 150 cellular functions. Despite the changes of tryptophan metabolites in both knockouts, only in the Oat1 knockout were multiple tryptophan-related cellular functions increased. Thus, deprived of the ability to take up kynurenine, kynurenate, anthranilate, and N-formylanthranilate through OAT1, the kidney responds by activating its own tryptophan-related biosynthetic pathways. The results support the Remote Sensing and Signaling Theory, which describes how “drug” transporters help optimize levels of metabolites and signaling molecules by facilitating organ cross talk. Since OAT1 and OAT3 are inhibited by many drugs, the data implies potential for drug–metabolite interactions. Indeed, treatment of humans with probenecid, an OAT-inhibitor used to treat gout, elevated circulating tryptophan metabolites. Furthermore, given that regulatory agencies have recommended drugs be tested for OAT1 and OAT3 binding or transport, it follows that these metabolites can be used as endogenous biomarkers to determine if drug candidates interact with OAT1 and/or OAT3.
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Affiliation(s)
- Jeffry C Granados
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
| | - Anne Richelle
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Jahir M Gutierrez
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
| | - Patrick Zhang
- Department of Biology, University of California San Diego, La Jolla, California, USA
| | - Xinlian Zhang
- Division of Biostatistics and Bioinformatics, Department of Family Medicine and Public Health, University of California San Diego, La Jolla, California, USA
| | - Vibha Bhatnagar
- Department of Family and Preventative Medicine, University of California San Diego, La Jolla, California, USA
| | - Nathan E Lewis
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA; Department of Pediatrics, University of California San Diego, La Jolla, California, USA; Novo Nordisk Foundation Center for Biosustainability at UC San Diego, University of California San Diego, La Jolla, California, USA
| | - Sanjay K Nigam
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA; Department of Medicine, University of California San Diego, La Jolla, California, USA.
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Cioè-Peña EC, Granados JC, Wrightsmith LL, Henriquez-Vigil AL, Moresky RT. Development and implementation of a hospital-based trauma response system in an urban hospital in San Salvador, El Salvador. Trauma 2016. [DOI: 10.1177/1460408616672491] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background In El Salvador, over 32% of all deaths are due to trauma. However, El Salvador lacks any established standardized trauma response system to treat the most critical of Salvadoran patients. In an effort to improve trauma response in El Salvador, we assessed the impact of a trauma-specific skills training, which could improve trauma care in a setting where no formal trauma training exists. Methods We used a pre- and post-interventional design study to measure the critical actions performed during a trauma event, as well as the case-fatality rate, emergency ward-to-operating room time, and utilization of ultrasound. The intervention was a primary trauma care course taught to all study participants. Results Eighteen providers were observed over a six-month period and 194 patient encounters (48 pre- and 146 post-intervention) were recorded. There was no significant difference in observed critical actions during major trauma between the pre-intervention and post-intervention periods. There was a significant improvement in ultrasound usage post-intervention (9.5% to 21.4%; p = 0.04). Conclusion The lack of behavior change observed following a two-day trauma training underscores the gap between physician knowledge and applied behavior change. This is a limited single center study, but further examination is necessary to determine the role of two-day training courses in the larger context of behavior change within a health system that has no formal post-graduate training in or defined algorithmic trauma care.
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Affiliation(s)
- EC Cioè-Peña
- Department of Emergency Medicine, Division of Global Health, Northwell Staten Island University Hospital, Staten Island, NY, USA
| | - JC Granados
- Department of Emergency Medicine, Kings County Hospital Center, NY, USA
| | - LL Wrightsmith
- sidHARTe Program of Heilbrunn Department of Population and Family Health, Columbia University Mailman School of Public Health, NY, USA
| | | | - RT Moresky
- sidHARTe Program of Heilbrunn Department of Population and Family Health, Columbia University Mailman School of Public Health, NY, USA
- Division of Emergency Medicine, Columbia University Medical Center, NY, USA
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Randtke EA, Granados JC, Howison CM, Pagel MD, Cárdenas-Rodríguez J. Multislice CEST MRI improves the spatial assessment of tumor pH. Magn Reson Med 2016; 78:97-106. [PMID: 27465207 DOI: 10.1002/mrm.26348] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/25/2016] [Accepted: 06/28/2016] [Indexed: 12/19/2022]
Abstract
PURPOSE Multislice maps of extracellular pH (pHe) are needed to interrogate the heterogeneities of tumors and normal organs. To address this need, we have developed a multislice chemical exchange saturation transfer (CEST) MRI acquisition method with a CEST spectrum-fitting method that measures in vivo pHe over a range of 6.3 to 7.4. METHODS The phase offset multiplanar (POMP) method was adapted for CEST fast imaging with steady-state free precession (FISP) MRI to acquire multiple image slices with a single CEST saturation pulse. The Bloch-McConnell equations were modified to include pH based on a calibration of pH and chemical exchange rate for the contrast agent iopamidol. These equations were used to estimate the pixel-wise pHe values throughout the multislice acidoCEST MR images of the tumor, kidney, bladder, and other tissues of a MDA-MB-231 tumor model. RESULTS Multislice acidoCEST MRI successfully mapped a gradient of pHe from 6.73 to 6.81 units from the tumor core to rim, and also mapped a gradient of pHe 6.56 to 6.97 across the mouse kidney. The bladder was found to be pHe 6.3. CONCLUSION AcidoCEST MRI with POMP acquisition and Bloch-McConnel analysis can map pHe in multiple imaging slices through the tumor, kidney, and bladder. This multislice evaluation facilitates assessments of spatial heterogeneity of tissue pHe. Magn Reson Med 78:97-106, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Edward A Randtke
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | - Jeffry C Granados
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA
| | | | - Mark D Pagel
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | - Julio Cárdenas-Rodríguez
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.,Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA
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