A key role for the transporter OAT1 in systemic lipid metabolism.
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ABSTRACT:
SUBMITTER: Granados JC
PROVIDER: S-EPMC8102404 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description: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.
| S-EPMC8102410 | biostudies-literature
Project description:The intrinsic connection between inflammation and tumor promotion is well characterized and is a key pathogenic event in patients with colorectal cancer (CRC), the second most common cause of tumor-related death in western countries. Environmental factors and chronic inflammation represent the major causes of intestinal carcinogenesis. In fact, patients suffering from inflammatory bowel diseases, including Crohn’s disease and Ulcerative Colitis (UC), have high risk of developing colitis-associated CRC with poor prognoses. Therefore, targeting the cancer-associated inflammation may offer new avenues for cancer treatment. In fact, several anti-inflammatory drugs, have been used for prophylaxis and have shown efficacy in contrasting cancer, despite various adverse side effects. Thus, there is an urgent need to discover novel cancer-associated mechanisms to develop alternative therapies that may reduce aberrant inflammatory responses without interfering with physiological defenses against infection and functional anti-tumor immunity. A novel approach promoting anti-tumor immunity has been recently proposed after the discovery of potent, endogenous, specialized pro-resolving mediators (SPMs), including lipoxins, resolvins, protectins, and maresins, mainly derived from omega-3 polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) via COX, LOX and CYP450 pathways, mediated by MFSD2A. Due to the potent bioactivity of SPMs in resolving inflammation and because of the correlation between inflammation and cancer, the roles of these lipid mediators have attracted great attention for their potential therapeutic role in cancer treatment, including CRC. Nevertheless, the understanding of the endogenous mechanisms that limit the inflammatory response during CRC development is incomplete and requires further investigation.
Based on the preliminary results indicating that dysfunctional MFSD2A-dependent pro-resolving pathways may foster CRC development, the investigators aim to define the functional role of MFSD2A in orchestrating pro-resolving pathways in the intestinal endothelium of metastatic and not metastatic CRC patients.
This is a cross-sectional single-center observational study involving patients with CRC. The investigators will enroll 15 patients with colorectal cancer (CRC) stratified by tumor stage (T0 / T1-T4, M0 / M1, N0 / N1 / N2) undergoing surgery in the Gastroenterology and Digestive Endoscopy unit within Gastro Center (IRCCS Ospedale San Raffaele).
Human Intestinal Microvascular Endothelial Cells (HIMEC) will be generated from each sample of cancer surgical specimens, while the healthy cells will be derived from the healthy margins of the colorectal resection of the same CRC patients.
MFSD2A will be overexpressed or silenced and the investigators will evaluate its biological effects in both tumor-derived HIMECs and healthy tissue-derived HIMECs through transcriptomics and lipidomics analysis. The investigators will also exploit a possible novel therapy based on the delivery of MFSD2A encoding plasmid-conjugated liposomes.
| 108244 | ecrin-mdr-crc
Project description:There has been a recent interest in the broader physiological importance of multispecific "drug" transporters of the SLC and ABC transporter families. Here, a novel multi-tiered systems biology approach was used to predict metabolites and signaling molecules potentially affected by the in vivo deletion of organic anion transporter 1 (Oat1, Slc22a6, originally NKT), a major kidney-expressed drug transporter. Validation of some predictions in wet-lab assays, together with re-evaluation of existing transport and knock-out metabolomics data, generated an experimentally validated, confidence ranked set of OAT1-interacting endogenous compounds enabling construction of an "OAT1-centered metabolic interaction network." Pathway and enrichment analysis indicated an important role for OAT1 in metabolism involving: the TCA cycle, tryptophan and other amino acids, fatty acids, prostaglandins, cyclic nucleotides, odorants, polyamines, and vitamins. The partly validated reconstructed network is also consistent with a major role for OAT1 in modulating metabolic and signaling pathways involving uric acid, gut microbiome products, and so-called uremic toxins accumulating in chronic kidney disease. Together, the findings are compatible with the hypothesized role of drug transporters in remote inter-organ and inter-organismal communication: The Remote Sensing and Signaling Hypothesis (Nigam, S. K. (2015) Nat. Rev. Drug Disc. 14, 29). The fact that OAT1 can affect many systemic biological pathways suggests that drug-metabolite interactions need to be considered beyond simple competition for the drug transporter itself and may explain aspects of drug-induced metabolic syndrome. Our approach should provide novel mechanistic insights into the role of OAT1 and other drug transporters implicated in metabolic diseases like gout, diabetes, and chronic kidney disease.
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Project description:Fermentative aromas play a key role in the organoleptic profile of young wines. Their production depends both on yeast strain and fermentation conditions. A present-day trend in the wine industry consists in developing new strains with aromatic properties using adaptive evolution approaches. An evolved strain, Affinity™ ECA5, overproducing esters, was recently obtained. In this study, dynamics of nitrogen consumption and of the fermentative aroma synthesis of the evolved and its ancestral strains were compared and coupled with a transcriptomic analysis approach to better understand the metabolic reshaping of Affinity™ ECA5.Nitrogen assimilation was different between the two strains, particularly amino acids transported by carriers regulated by nitrogen catabolite repression. We also observed differences in the kinetics of fermentative aroma production, especially in the bioconversion of higher alcohols into acetate esters. Finally, transcriptomic data showed that the enhanced bioconversion into acetate esters by the evolved strain was associated with the repression of genes involved in sterol biosynthesis rather than an enhanced expression of ATF1 and ATF2 (genes coding for the enzymes responsible for the synthesis of acetate esters from higher alcohols).An integrated approach to yeast metabolism-combining transcriptomic analyses and online monitoring data-showed differences between the two strains at different levels. Differences in nitrogen source consumption were observed suggesting modifications of NCR in the evolved strain. Moreover, the evolved strain showed a different way of managing the lipid source, which notably affected the production of acetate esters, likely because of a greater availability of acetyl-CoA for the evolved strain.
| S-EPMC4748530 | biostudies-literature
Project description:Peroxisomes metabolize a specific subset of fatty acids, which include dicarboxylic fatty acids (DCAs) generated by ω-oxidation. Data obtained in vitro suggest that the peroxisomal transporter ABCD3 (also known as PMP70) mediates the transport of DCAs into the peroxisome, but in vivo evidence to support this role is lacking. In this work, we studied an Abcd3 KO mouse model generated by CRISPR-Cas9 technology using targeted and untargeted metabolomics, histology, immunoblotting, and stable isotope tracing technology. We show that ABCD3 functions in hepatic DCA metabolism and uncover a novel role for this peroxisomal transporter in lipid homeostasis. The Abcd3 KO mouse presents with increased hepatic long-chain DCAs, increased urine medium-chain DCAs, lipodystrophy, enhanced hepatic cholesterol synthesis and decreased hepatic de novo lipogenesis. Moreover, our study suggests that DCAs are metabolized by mitochondrial fatty acid β-oxidation when ABCD3 is not functional, reflecting the importance of the metabolic compartmentalization and communication between peroxisomes and mitochondria. In summary, this study provides data on the role of the peroxisomal transporter ABCD3 in hepatic lipid homeostasis and DCA metabolism, and the consequences of peroxisomal dysfunction for the liver.
| S-EPMC8578467 | biostudies-literature
Project description:In vitro data indicates that the kidney proximal tubule (PT) transporters of uremic toxins and solutes (e.g., indoxyl sulfate, p-cresol sulfate, kynurenine, creatinine, urate) include two "drug" transporters of the organic anion transporter (OAT) family: OAT1 (SLC22A6, originally NKT) and OAT3 (SLC22A8). Here, we have examined new and prior metabolomics data from the Oat1KO and Oat3KO, as well as newly obtained metabolomics data from a "chemical double" knockout (Oat3KO plus probenecid). This gives a picture of the in vivo roles of OAT1 and OAT3 in the regulation of the uremic solutes and supports the centrality of these "drug" transporters in independently and synergistically regulating uremic metabolism. We demonstrate a key in vivo role for OAT1 and/or OAT3 in the handling of over 35 uremic toxins and solutes, including those derived from the gut microbiome (e.g., CMPF, phenylsulfate, indole-3-acetic acid). Although it is not clear whether trimethylamine-N-oxide (TMAO) is directly transported, the Oat3KO had elevated plasma levels of TMAO, which is associated with cardiovascular morbidity in chronic kidney disease (CKD). As described in the Remote Sensing and Signaling (RSS) Hypothesis, many of these molecules are involved in interorgan and interorganismal communication, suggesting that uremia is, at least in part, a disorder of RSS.
| S-EPMC5504054 | biostudies-literature
Project description:Organic anion transporter 1 (OAT1) is a polyspecific transport protein located in the basolateral membrane of renal proximal tubule cells. OAT1 plays a pivotal role in drug clearance. Adverse drug reactions (ADR) are observed more frequently in women than in men, especially ADR are higher in women for drugs which are known interactors of OAT1. Sex-dependent expression of Oat1 has been observed in rodents with a tendency to male-dominant expression. This study aims at elucidating the transcriptional regulation of human OAT1 and tests the effect of estrogen receptor α (ERα). Promoter activation of OAT1 was assessed by luciferase assays carried out by Opossum kidney (OK) cells, transiently transfected with promoter constructs of human OAT1 and expression vectors for ERα and exposed to 100 nmol/L 17β-estradiol. Furthermore, a transcription factor array and proteomic analysis was performed to identify estrogen-induced transcription factors. Human OAT1 was significantly activated by ligand activated ERα. However, activation occurred without a direct interaction of ERα with the OAT1 promoter. Our data rather show an activation of the transcription factors CCAAT-box-binding transcription factor (CBF) and heterogeneous nuclear ribonucleoprotein K (HNRNPK) by ERα, which in turn bind and initiate OAT1 promoter activity. Herewith, we provide novel evidence of estrogen-dependent, transcriptional regulation of polyspecific drug transporters including the estrogen-induced transcription factors CBF and HNRNPK.
| S-EPMC6854606 | biostudies-literature
Project description:Diverse metabolic disorders have been associated with an alteration of N-acylethanolamine (NAE) levels. These bioactive lipids are synthesized mainly by N-acylphosphatidylethanolamine-selective phospholipase D (NAPE-PLD) and influence host metabolism. We have previously discovered that NAPE-PLD in the intestine and adipose tissue is connected to the pathophysiology of obesity. However, the physiological function of NAPE-PLD in the liver remains to be deciphered. To study the role of liver NAPE-PLD on metabolism, we generated a new mouse model of inducible Napepld hepatocyte-specific deletion (Napepld?Hep mice). In this study, we report that Napepld?Hep mice develop a high-fat diet-like phenotype, characterized by an increased fat mass gain, hepatic steatosis and we show that Napepld?Hep mice are more sensitive to liver inflammation. We also demonstrate that the role of liver NAPE-PLD goes beyond the mere synthesis of NAEs, since the deletion of NAPE-PLD is associated with a marked modification of various bioactive lipids involved in host homeostasis such as oxysterols and bile acids. Collectively these data suggest that NAPE-PLD in hepatocytes is a key regulator of liver bioactive lipid synthesis and a dysregulation of this enzyme leads to metabolic complications. Therefore, deepening our understanding of the regulation of NAPE-PLD could be crucial to tackle obesity and related comorbidities.
| S-EPMC7291298 | biostudies-literature
Project description:Polymorphonuclear myeloid derived suppressor cells (PMN-MDSC) are pathologically activated neutrophils that accumulate in cancer and many other pathologic conditions. PMN-MDSC are critically important for the regulation of immune responses in cancer, promotion of tumor progression, and metastases. Despite the recent advances in understanding of the PMN-MDSC biology, the mechanisms responsible for pathological activation of neutrophils are not well defined, which limit selective targeting of PMN-MDSC. Here, we report that mouse and human PMN-MDSC exclusively up-regulate fatty acid transporter protein 2 (FATP2). Over-expression of FATP2 in PMN-MDSC was controlled by GM-CSF, through the activation of STAT5 transcription factor. Genetic ablation of FATP2 abrogated the suppressive activity of PMN-MDSC in spleens and tumors. FATP2 in neutrophils promoted accumulation of oxidized lipids. However, the main mechanism of FATP2 mediated suppressive activity of PMN-MDSC involved uptake of arachidonic acid and synthesis of prostaglandin E2. The selective pharmacological inhibition of FATP2 abrogated activity of PMN-MSC and substantially delayed tumor progression. In combination with check-point inhibitors it blocked tumor progression in mice. Thus, FATP2 mediates acquisition of immune suppressive activity by PMN-MDSC and represents a new target to inhibit the functions of PMN-MDSC and improve the effect of immunotherapy of cancer.
2019-05-09 | GSE126885 | GEO