1
|
Medeot AC, Boaglio AC, Salas G, Maidagan PM, Miszczuk GS, Barosso IR, Sánchez Pozzi EJ, Crocenzi FA, Roma MG. Tauroursodeoxycholate prevents estradiol 17β-d-glucuronide-induced cholestasis and endocytosis of canalicular transporters by switching off pro-cholestatic signaling pathways. Life Sci 2024; 352:122839. [PMID: 38876186 DOI: 10.1016/j.lfs.2024.122839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 06/08/2024] [Accepted: 06/11/2024] [Indexed: 06/16/2024]
Abstract
AIMS Estradiol 17β-d-glucuronide (E217G) induces cholestasis by triggering endocytosis and further intracellular retention of the canalicular transporters Bsep and Mrp2, in a cPKC- and PI3K-dependent manner, respectively. Pregnancy-induced cholestasis has been associated with E217G cholestatic effect, and is routinely treated with ursodeoxycholic acid (UDCA). Since protective mechanisms of UDCA in E217G-induced cholestasis are still unknown, we ascertained here whether its main metabolite, tauroursodeoxycholate (TUDC), can prevent endocytosis of canalicular transporters by counteracting cPKC and PI3K/Akt activation. MAIN METHODS Activation of cPKC and PI3K/Akt was evaluated in isolated rat hepatocytes by immunoblotting (assessment of membrane-bound and phosphorylated forms, respectively). Bsep/Mrp2 function was quantified in isolated rat hepatocyte couplets (IRHCs) by assessing the apical accumulation of their fluorescent substrates, CLF and GS-MF, respectively. We also studied, in isolated, perfused rat livers (IPRLs), the status of Bsep and Mrp2 transport function, assessed by the biliary excretion of TC and DNP-SG, respectively, and Bsep/Mrp2 localization by immunofluorescence. KEY FINDINGS E217G activated both cPKC- and PI3K/Akt-dependent signaling, and pretreatment with TUDC significantly attenuated these activations. In IRHCs, TUDC prevented the E217G-induced decrease in apical accumulation of CLF and GS-MF, and inhibitors of protein phosphatases failed to counteract this protection. In IPRLs, E217G induced an acute decrease in bile flow and in the biliary excretion of TC and DNP-SG, and this was prevented by TUDC. Immunofluorescence studies revealed that TUDC prevented E217G-induced Bsep/Mrp2 endocytosis. SIGNIFICANCE TUDC restores function and localization of Bsep/Mrp2 impaired by E217G, by preventing both cPKC and PI3K/Akt activation in a protein-phosphatase-independent manner.
Collapse
Affiliation(s)
- Anabela C Medeot
- Institute of Experimental Physiology (IFISE-CONICET), National University of Rosario, 2000 Rosario, Argentina
| | - Andrea C Boaglio
- Institute of Experimental Physiology (IFISE-CONICET), National University of Rosario, 2000 Rosario, Argentina
| | - Gimena Salas
- Institute of Experimental Physiology (IFISE-CONICET), National University of Rosario, 2000 Rosario, Argentina
| | - Paula M Maidagan
- Institute of Experimental Physiology (IFISE-CONICET), National University of Rosario, 2000 Rosario, Argentina
| | - Gisel S Miszczuk
- Institute of Experimental Physiology (IFISE-CONICET), National University of Rosario, 2000 Rosario, Argentina
| | - Ismael R Barosso
- Institute of Experimental Physiology (IFISE-CONICET), National University of Rosario, 2000 Rosario, Argentina
| | - Enrique J Sánchez Pozzi
- Institute of Experimental Physiology (IFISE-CONICET), National University of Rosario, 2000 Rosario, Argentina
| | - Fernando A Crocenzi
- Institute of Experimental Physiology (IFISE-CONICET), National University of Rosario, 2000 Rosario, Argentina
| | - Marcelo G Roma
- Institute of Experimental Physiology (IFISE-CONICET), National University of Rosario, 2000 Rosario, Argentina.
| |
Collapse
|
2
|
Liu M, Li X, Wang J, Ji Y, Gu J, Wei Y, Peng L, Tian C, Lv P, Wang P, Liu X, Li W. Identification and validation of Rab11a in Rat orofacial inflammatory pain model induced by CFA. Neurochem Int 2023:105550. [PMID: 37268020 DOI: 10.1016/j.neuint.2023.105550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 04/29/2023] [Accepted: 05/14/2023] [Indexed: 06/04/2023]
Abstract
Orofacial pain (OFP) is a clinically very common and the most troubling condition; however, there is few effective way to relieve OFP. Rab11a, a small molecule guanosine triphosphate enzyme, is one of the Rab member family playing a vital role in intracellular endocytosis and the pain process. Therefore, we investigated the hub genes of rat OFP model induced by Complete Freund's Adjuvant (CFA) via re-analyzing microarray data (GSE111160). We found that Rab11a acted as a key hub gene in the process of OFP. During the validation of Rab11a, the OFP model was established by peripheral injection of CFA, which decreased the head withdrawal threshold (HWT) and head withdrawal lantency (HWL). Rab11a was observed in NeuN of Sp5C instead of GFAP/IBA-1, and double-IF of Rab11a and Fos positive cells were increased on the 7th day after CFA modeling statistically. Rab11a protein expression in TG and Sp5C of CFA group was also significantly increased. Interestingly, injection of Rab11a-targeted short hairpin RNA (Rab11a-shRNA) into Sp5C could reverse the decrease in HWT and HWL and reduce the expression level of Rab11a. Electrophysiological recording further demonstrated that the activity of Sp5C neuron was improved in CFA group, while Rab11a-shRNA considerably decreased the enhancement of Sp5C neuronal activity. Finally, we detected the expression level of p-PI3K, p-AKT, and p-mTOR in Sp5C of rats after injecting the Rab11a-shRNA virus. To our surprise, CFA upregulated the phosphorylation of PI3K, AKT and mTOR in Sp5C, and Rab11a-shRNA downregulated these molecules' expression. Our data suggest that CFA activates the PI3K/AKT signaling pathway through up-regulating Rab11a expression, which can induce OFP hyperalgesia development furtherly. Targeting Rab11a may be a novel treatment strategy for OFP.
Collapse
Affiliation(s)
- Miaomiao Liu
- Department of Respiratory and Critical Care Medicine, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xin Li
- Department of Stomatology, The 960th Hospital of People's Liberation Army, Jinan, Shandong, China
| | - Jian Wang
- Department of Neurosurgery, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yuanyuan Ji
- Department of Anatomy, School of Medicine, Northwest University, Xi'an, Shaanxi, China
| | - Junxiang Gu
- Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Yi Wei
- Department of Anatomy, School of Medicine, Northwest University, Xi'an, Shaanxi, China
| | - Liwei Peng
- Department of Neurosurgery, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Chao Tian
- Department of Neurosurgery, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Peiyuan Lv
- Department of Neurosurgery, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Peng Wang
- Department of Neurosurgery, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xin Liu
- Department of Stomatology, The 960th Hospital of People's Liberation Army, Jinan, Shandong, China.
| | - Weixin Li
- Department of Neurosurgery, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shaanxi, China.
| |
Collapse
|
3
|
Sousa D, Lima RT, Lopes-Rodrigues V, Gonzalez E, Royo F, Xavier CPR, Falcón-Pérez JM, Vasconcelos MH. Different Ability of Multidrug-Resistant and -Sensitive Counterpart Cells to Release and Capture Extracellular Vesicles. Cells 2021; 10:cells10112886. [PMID: 34831110 PMCID: PMC8616370 DOI: 10.3390/cells10112886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 12/24/2022] Open
Abstract
Cancer multidrug resistance (MDR) is one of the main challenges for cancer treatment efficacy. MDR is a phenomenon by which tumor cells become resistant to several unrelated drugs. Some studies have previously described the important role of extracellular vesicles (EVs) in the dissemination of a MDR phenotype. EVs’ cargo may include different players of MDR, such as microRNAS and drug-efflux pumps, which may be transferred from donor MDR cells to recipient drug-sensitive counterparts. The present work aimed to: (i) compare the ability of drug-sensitive and their MDR counterpart cells to release and capture EVs and (ii) study and relate those differences with possible distinct fate of the endocytic pathway in these counterpart cells. Our results showed that MDR cells released more EVs than their drug-sensitive counterparts and also that the drug-sensitive cells captured more EVs than their MDR counterparts. This difference in the release and capture of EVs may be associated with differences in the endocytic pathway between drug-sensitive and MDR cells. Importantly, manipulation of the recycling pathway influenced the response of drug-sensitive cells to doxorubicin treatment.
Collapse
Affiliation(s)
- Diana Sousa
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (D.S.); (R.T.L.); (V.L.-R.); (C.P.R.X.)
- Cancer Drug Resistance Group, IPATIMUP—Institute of Molecular Pathology and Immunology of the University of Porto, 4200-135 Porto, Portugal
- Department of Biological Sciences, FFUP—Faculty of Pharmacy of the University of Porto, 4050-313 Porto, Portugal
| | - Raquel T. Lima
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (D.S.); (R.T.L.); (V.L.-R.); (C.P.R.X.)
- Cancer Drug Resistance Group, IPATIMUP—Institute of Molecular Pathology and Immunology of the University of Porto, 4200-135 Porto, Portugal
- Department of Pathology, FMUP—Faculty of Medicine of the University of Porto, 4200-319 Porto, Portugal
- Cancer Signaling & Metabolism Group, IPATIMUP—Institute of Molecular Pathology and Immunology of the University of Porto, 4200-135 Porto, Portugal
| | - Vanessa Lopes-Rodrigues
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (D.S.); (R.T.L.); (V.L.-R.); (C.P.R.X.)
- Cancer Drug Resistance Group, IPATIMUP—Institute of Molecular Pathology and Immunology of the University of Porto, 4200-135 Porto, Portugal
- ICBAS-UP—Institute of Biomedical Sciences Abel Salazar of the University of Porto, 4099-003 Porto, Portugal
| | - Esperanza Gonzalez
- Exosomes Lab. & Metabolomics Platform, CIC bioGUNE, CIBERehd, 28160 Derio, Spain; (E.G.); (F.R.); (J.M.F.-P.)
| | - Félix Royo
- Exosomes Lab. & Metabolomics Platform, CIC bioGUNE, CIBERehd, 28160 Derio, Spain; (E.G.); (F.R.); (J.M.F.-P.)
| | - Cristina P. R. Xavier
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (D.S.); (R.T.L.); (V.L.-R.); (C.P.R.X.)
- Cancer Drug Resistance Group, IPATIMUP—Institute of Molecular Pathology and Immunology of the University of Porto, 4200-135 Porto, Portugal
| | - Juan M. Falcón-Pérez
- Exosomes Lab. & Metabolomics Platform, CIC bioGUNE, CIBERehd, 28160 Derio, Spain; (E.G.); (F.R.); (J.M.F.-P.)
- IKERBASQUE Basque Foundation for Science, 48013 Bilbao, Spain
| | - M. Helena Vasconcelos
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (D.S.); (R.T.L.); (V.L.-R.); (C.P.R.X.)
- Cancer Drug Resistance Group, IPATIMUP—Institute of Molecular Pathology and Immunology of the University of Porto, 4200-135 Porto, Portugal
- Department of Biological Sciences, FFUP—Faculty of Pharmacy of the University of Porto, 4050-313 Porto, Portugal
- Correspondence: ; Tel.: +351-225-570-772
| |
Collapse
|
4
|
RAB10 Interacts with ABCB4 and Regulates Its Intracellular Traffic. Int J Mol Sci 2021; 22:ijms22137087. [PMID: 34209301 PMCID: PMC8268348 DOI: 10.3390/ijms22137087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 12/11/2022] Open
Abstract
ABCB4 (ATP-binding cassette subfamily B member 4) is an ABC transporter expressed at the canalicular membrane of hepatocytes where it ensures phosphatidylcholine secretion into bile. Genetic variations of ABCB4 are associated with several rare cholestatic diseases. The available treatments are not efficient for a significant proportion of patients with ABCB4-related diseases and liver transplantation is often required. The development of novel therapies requires a deep understanding of the molecular mechanisms regulating ABCB4 expression, intracellular traffic, and function. Using an immunoprecipitation approach combined with mass spectrometry analyses, we have identified the small GTPase RAB10 as a novel molecular partner of ABCB4. Our results indicate that the overexpression of wild type RAB10 or its dominant-active mutant significantly increases the amount of ABCB4 at the plasma membrane expression and its phosphatidylcholine floppase function. Contrariwise, RAB10 silencing induces the intracellular retention of ABCB4 and then indirectly diminishes its secretory function. Taken together, our findings suggest that RAB10 regulates the plasma membrane targeting of ABCB4 and consequently its capacity to mediate phosphatidylcholine secretion.
Collapse
|
5
|
Straka T, Schröder C, Roos A, Kollipara L, Sickmann A, Williams MPI, Hafner M, Khan MM, Rudolf R. Regulatory Function of Sympathetic Innervation on the Endo/Lysosomal Trafficking of Acetylcholine Receptor. Front Physiol 2021; 12:626707. [PMID: 33776791 PMCID: PMC7991846 DOI: 10.3389/fphys.2021.626707] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 02/08/2021] [Indexed: 01/02/2023] Open
Abstract
Recent studies have demonstrated that neuromuscular junctions are co-innervated by sympathetic neurons. This co-innervation has been shown to be crucial for neuromuscular junction morphology and functional maintenance. To improve our understanding of how sympathetic innervation affects nerve–muscle synapse homeostasis, we here used in vivo imaging, proteomic, biochemical, and microscopic approaches to compare normal and sympathectomized mouse hindlimb muscles. Live confocal microscopy revealed reduced fiber diameters, enhanced acetylcholine receptor turnover, and increased amounts of endo/lysosomal acetylcholine-receptor-bearing vesicles. Proteomics analysis of sympathectomized skeletal muscles showed that besides massive changes in mitochondrial, sarcomeric, and ribosomal proteins, the relative abundance of vesicular trafficking markers was affected by sympathectomy. Immunofluorescence and Western blot approaches corroborated these findings and, in addition, suggested local upregulation and enrichment of endo/lysosomal progression and autophagy markers, Rab 7 and p62, at the sarcomeric regions of muscle fibers and neuromuscular junctions. In summary, these data give novel insights into the relevance of sympathetic innervation for the homeostasis of muscle and neuromuscular junctions. They are consistent with an upregulation of endocytic and autophagic trafficking at the whole muscle level and at the neuromuscular junction.
Collapse
Affiliation(s)
- Tatjana Straka
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, Mannheim, Germany.,Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Charlotte Schröder
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany
| | - Andreas Roos
- Department of Neuropediatrics, University Hospital Essen, Essen, Germany.,Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | | | - Albert Sickmann
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany.,Department of Chemistry, College of Physical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,Medizinische Fakultät, Medizinische Proteom-Center (MPC), Ruhr-Universität Bochum, Bochum, Germany
| | | | - Mathias Hafner
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, Mannheim, Germany
| | - Muzamil Majid Khan
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, Mannheim, Germany.,Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Rüdiger Rudolf
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, Mannheim, Germany.,Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany
| |
Collapse
|
6
|
A Link between Intrahepatic Cholestasis and Genetic Variations in Intracellular Trafficking Regulators. BIOLOGY 2021; 10:biology10020119. [PMID: 33557414 PMCID: PMC7914782 DOI: 10.3390/biology10020119] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/27/2021] [Accepted: 02/01/2021] [Indexed: 12/20/2022]
Abstract
Simple Summary Cholestasis refers to a medical condition in which the liver is not capable of secreting bile. The consequent accumulation of toxic bile components in the liver leads to liver failure. Cholestasis can be caused by mutations in genes that code for proteins involved in bile secretion. Recently mutations in other genes have been discovered in patients with cholestasis of unknown origin. Interestingly, many of these newly discovered genes code for proteins that regulate the intracellular distribution of other proteins, including those involved in bile secretion. This group of genes thus suggests the deregulated intracellular distribution of bile-secreting proteins as an important but still poorly understood mechanism that underlies cholestasis. To expedite a better understanding of this mechanism, we have reviewed these genes and their mutations and we discuss these in the context of cholestasis. Abstract Intrahepatic cholestasis is characterized by the accumulation of compounds in the serum that are normally secreted by hepatocytes into the bile. Genes associated with familial intrahepatic cholestasis (FIC) include ATP8B1 (FIC1), ABCB11 (FIC2), ABCB4 (FIC3), TJP2 (FIC4), NR1H4 (FIC5) and MYO5B (FIC6). With advanced genome sequencing methodologies, additional mutated genes are rapidly identified in patients presenting with idiopathic FIC. Notably, several of these genes, VPS33B, VIPAS39, SCYL1, and AP1S1, together with MYO5B, are functionally associated with recycling endosomes and/or the Golgi apparatus. These are components of a complex process that controls the sorting and trafficking of proteins, including those involved in bile secretion. These gene variants therefore suggest that defects in intracellular trafficking take a prominent place in FIC. Here we review these FIC-associated trafficking genes and their variants, their contribution to biliary transporter and canalicular protein trafficking, and, when perturbed, to cholestatic liver disease. Published variants for each of these genes have been summarized in table format, providing a convenient reference for those who work in the intrahepatic cholestasis field.
Collapse
|
7
|
Zhang ZY, Lu M, Liu ZK, Li H, Yong YL, Zhang RY, Chen ZN, Bian H. Rab11a regulates MMP2 expression by activating the PI3K/AKT pathway in human hepatocellular carcinoma cells. Pathol Res Pract 2020; 216:153046. [PMID: 32825931 DOI: 10.1016/j.prp.2020.153046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 05/17/2020] [Accepted: 05/31/2020] [Indexed: 02/06/2023]
Abstract
As a member of the Rab GTPase family, Rab11a plays an important role in vesicle transport and tumor progression. However, it is not clear whether it can also be used as an oncoprotein in hepatocellular carcinoma (HCC). In this study, database and immunohistochemical analyses showed that Rab11a was highly expressed in HCC tissues, and associated with poor clinical prognosis. Rab11a overexpression promoted the proliferation, migration, invasion, and anti-apoptosis of human HCC cell lines, MHCC-97H and HCC-LM3, whereas the downregulation of Rab11a inhibited these biological tumor activities. Nude mice xenograft demonstrated that Rab11a had a positive effect on the growth of hepatocellular carcinoma cells in vivo. Further studies found that the PI3K/AKT pathway and matrix metalloproteinase 2 (MMP2) upregulation can be activated by over-expression of Rab11a. However, MMP2 upregulation induced by Rab11a can be inhibited by the PI3K/AKT pathway inhibitor, LY294002. Altogether, our study established for the first time that Rab11a can play a pro-cancer role in HCC, as a novel oncoprotein, by activating the PI3K/AKT pathway to regulate MMP2 expression.
Collapse
Affiliation(s)
- Zhi-Yun Zhang
- Department of Cell Biology, National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Meng Lu
- Department of Cell Biology, National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Ze-Kun Liu
- Department of Cell Biology, National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Hao Li
- Department of Cell Biology, National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Le Yong
- Department of Cell Biology, National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Ren-Yu Zhang
- Department of Cell Biology, National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Zhi-Nan Chen
- Department of Cell Biology, National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, 710032, China.
| | - Huijie Bian
- Department of Cell Biology, National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, 710032, China.
| |
Collapse
|
8
|
Ogura J, Yamaguchi H, Mano N. Stimulatory effect on the transport mediated by organic anion transporting polypeptide 2B1. Asian J Pharm Sci 2020; 15:181-191. [PMID: 32373198 PMCID: PMC7193449 DOI: 10.1016/j.ajps.2019.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 10/09/2019] [Accepted: 10/15/2019] [Indexed: 12/11/2022] Open
Abstract
Drug-drug interaction (DDI) is one of causes of adverse drug events and can result in life-threatening consequences. Organic anion-transporting polypeptide (OATP) 2B1 is a major uptake transporter in the intestine and contributes to transport various clinically used therapeutic agents. The intestine has a high risk of DDI, because it has a special propensity to be exposed to a high concentration of drugs. Thus, understanding drug interaction mediated by OATP2B1 in the absorption process is important for the prevention of adverse drug events, including decrease in the therapeutic effect of co-administered drugs. Acute drug interaction occurs through the direct inhibitory effect on transporters, including OATP2B1. Moreover, some compounds such as clinically used drugs and food components have an acute stimulatory effect on transport of co-administered drugs by OATP2B1. This review summarizes the acute stimulatory effect on the transport mediated by OATP2B1 and discusses the mechanisms of the acute stimulatory effects of compounds. There are two types of acute stimulatory effects, substrate-independent and -dependent interactions on OATP2B1 function. The facilitating translocation of OATP2B1 to the plasma membrane is one of causes for the substrate-independent acute stimulatory effect. On the contrary, the substrate-dependent effect is based on the direct binding to the substrate-binding site or allosteric progesterone-binding site of OATP2B1.
Collapse
Affiliation(s)
- Jiro Ogura
- Corresponding author. Tohoku University Hospital, Department of Pharmaceutical Sciences, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan. Tel.: +81 22 7177541
| | | | | |
Collapse
|
9
|
Shearn CT, Fennimore B, Orlicky DJ, Gao YR, Saba LM, Battista KD, Aivazidis S, Assiri M, Harris PS, Michel C, Merrill GF, Schmidt EE, Colgan SP, Petersen DR. Cholestatic liver disease results increased production of reactive aldehydes and an atypical periportal hepatic antioxidant response. Free Radic Biol Med 2019; 143:101-114. [PMID: 31377417 PMCID: PMC6848778 DOI: 10.1016/j.freeradbiomed.2019.07.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/30/2019] [Accepted: 07/31/2019] [Indexed: 01/22/2023]
Abstract
Cholangiopathies such as primary sclerosing cholangitis (PSC) are chronic liver diseases characterized by increased cholestasis, biliary inflammation and oxidative stress. The objective of this study was to elucidate the impact of cholestatic injury on oxidative stress-related factors. Using hepatic tissue and whole cell liver extracts (LE) isolated from 11-week old C57BL/6J (WT) and Mdr2KO mice, inflammation and oxidative stress was assessed. Concurrently, specific targets of carbonylation were assessed in LE prepared from murine groups as well as from normal and human patients with end-stage PSC. Identified carbonylated proteins were further evaluated using bioinformatics analyses. Picrosirius red staining revealed extensive fibrosis in Mdr2KO liver, and fibrosis colocalized with increased periportal inflammatory cells and both acrolein and 4-HNE staining. Western blot analysis revealed elevated periportal expression of antioxidant proteins Cbr3, GSTμ, Prdx5, TrxR1 and HO-1 but not GCLC, GSTπ or catalase in the Mdr2KO group when compared to WT. From immunohistochemical analysis, increased periportal reactive aldehyde production colocalized with elevated staining of Cbr3, GSTμ and TrxR1 but surprisingly not with Nrf2. Mass spectrometric analysis revealed an increase in carbonylated proteins in the Mdr2KO and PSC groups compared to respective controls. Gene ontology and KEGG pathway analysis of carbonylated proteins revealed a propensity for increased carbonylation of proteins broadly involved in metabolic processes as well more specifically in Rab-mediated signal transduction, lysosomes and the large ribosomal subunit in human PSC. Western blot analysis of Rab-GTPase expression revealed no significant differences in Mdr2KO mice when compared to WT livers. In contrast, PSC tissue exhibited decreased levels of Rabs 4, 5 and increased abundance of Rabs 6 and 9a protein. Results herein reveal that cholestasis induces stage-dependent increases in periportal oxidative stress responses and protein carbonylation, potentially contributing to pathogenesis in Mdr2KO. Furthermore, during early stage cholestasis, there is cell-specific upregulation of some but not all, antioxidant proteins.
Collapse
Affiliation(s)
- Colin T Shearn
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States.
| | - Blair Fennimore
- Department of Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - David J Orlicky
- Department of Pathology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Yue R Gao
- Department of Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Laura M Saba
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Kayla D Battista
- Department of Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Stefanos Aivazidis
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Mohammed Assiri
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Peter S Harris
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Cole Michel
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Gary F Merrill
- Department of Biochemistry and Biophysics, Oregon State University, Corvalis, OR, 97331, United States
| | - Edward E Schmidt
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, 59717, United States
| | - Sean P Colgan
- Department of Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Dennis R Petersen
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| |
Collapse
|
10
|
Fu D, Cardona P, Ho H, Watkins PB, Brouwer KLR. Novel Mechanisms of Valproate Hepatotoxicity: Impaired Mrp2 Trafficking and Hepatocyte Depolarization. Toxicol Sci 2019; 171:431-442. [PMID: 31368504 PMCID: PMC6760262 DOI: 10.1093/toxsci/kfz154] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 12/14/2022] Open
Abstract
Drug-induced liver injury (DILI) remains a major challenge in drug development. Although numerous mechanisms for DILI have been identified, few studies have focused on loss of hepatocyte polarization as a DILI mechanism. The current study investigated the effects of valproate, an antiepileptic drug with DILI risk, on the cellular mechanisms responsible for loss of hepatocyte polarization. Fully polarized collagen sandwich-cultured rat hepatocytes were treated with valproate (1-20mM) for specified times (3-24hr). Hepatocyte viability was significantly decreased by 10mM and 20mM valproate. Valproate depolarized hepatocytes, even at non-cytotoxic concentrations (=5mM). Depolarization was associated with significantly decreased canalicular levels of multidrug resistance-associated protein 2 (Mrp2) resulting in reduced canalicular excretion of the Mrp2 substrate carboxydichlorofluorescein. The decreased canalicular Mrp2 was associated with intracellular accumulation of Mrp2 in Rab11-positive recycling endosomes and early endosomes. Mechanistic studies suggested that valproate inhibited canalicular trafficking of Mrp2. This effect of valproate on Mrp2 appeared to be selective in that valproate had less impact on canalicular levels of the bile salt export pump (Bsep) and no detectable effect on P-glycoprotein (P-gp) canalicular levels. Treatment with valproate for 24hr also significantly downregulated levels of tight junction-associated protein, zonula occludens 2 (ZO2), but appeared to have no effect on the levels of tight junction proteins claudin 1, claudin 2, occludin, ZO1 and ZO3. These findings reveal that two novel mechanisms may contribute to valproate hepatotoxicity: impaired canalicular trafficking of Mrp2 and disruption of ZO2-associated hepatocyte polarization.
Collapse
Affiliation(s)
- Dong Fu
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Panli Cardona
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Henry Ho
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Paul B Watkins
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Kim L R Brouwer
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC
| |
Collapse
|
11
|
Roma MG, Barosso IR, Miszczuk GS, Crocenzi FA, Pozzi EJS. Dynamic Localization of Hepatocellular Transporters: Role in Biliary Excretion and Impairment in Cholestasis. Curr Med Chem 2019; 26:1113-1154. [DOI: 10.2174/0929867325666171205153204] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 12/25/2022]
Abstract
Bile flow generation is driven by the vectorial transfer of osmotically active compounds from sinusoidal blood into a confined space, the bile canaliculus. Hence, localization of hepatocellular transporters relevant to bile formation is crucial for bile secretion. Hepatocellular transporters are localized either in the plasma membrane or in recycling endosomes, from where they can be relocated to the plasma membrane on demand, or endocytosed when the demand decreases. The balance between endocytic internalization/ exocytic targeting to/from this recycling compartment is therefore the main determinant of the hepatic capability to generate bile, and to dispose endo- and xenobiotics. Furthermore, the exacerbated endocytic internalization is a common pathomechanisms in both experimental and human cholestasis; this results in bile secretory failure and, eventually, posttranslational transporter downregulation by increased degradation. This review summarizes the proposed structural mechanisms accounting for this pathological condition (e.g., alteration of function, localization or expression of F-actin or F-actin/transporter cross-linking proteins, and switch to membrane microdomains where they can be readily endocytosed), and the mediators implicated (e.g., triggering of “cholestatic” signaling transduction pathways). Lastly, we discussed the efficacy to counteract the cholestatic failure induced by transporter internalization of a number of therapeutic experimental approaches based upon the use of compounds that trigger exocytic targetting of canalicular transporters (e.g., cAMP, tauroursodeoxycholate). This therapeutics may complement treatments aimed to transcriptionally improve transporter expression, by affording proper localization and membrane stability to the de novo synthesized transporters.
Collapse
Affiliation(s)
- Marcelo G. Roma
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
| | - Ismael R. Barosso
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
| | - Gisel S. Miszczuk
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
| | - Fernando A. Crocenzi
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
| | - Enrique J. Sánchez Pozzi
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
| |
Collapse
|
12
|
Dzierlenga AL, Cherrington NJ. Misregulation of membrane trafficking processes in human nonalcoholic steatohepatitis. J Biochem Mol Toxicol 2018; 32:e22035. [PMID: 29341352 DOI: 10.1002/jbt.22035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/21/2017] [Accepted: 12/27/2017] [Indexed: 12/17/2022]
Abstract
Nonalcoholic steatohepatitis (NASH) remodels the expression and function of genes and proteins that are critical for drug disposition. This study sought to determine whether disruption of membrane protein trafficking pathways in human NASH contributes to altered localization of multidrug resistance-associated protein 2 (MRP2). A comprehensive immunoblot analysis assessed the phosphorylation, membrane translocation, and expression of transporter membrane insertion regulators, including several protein kinases (PK), radixin, MARCKS, and Rab11. Radixin exhibited a decreased phosphorylation and total expression, whereas Rab11 had an increased membrane localization. PKCδ, PKCα, and PKA had increased membrane activation, whereas PKCε had a decreased phosphorylation and membrane expression. Radixin dephosphorylation may activate MRP2 membrane retrieval in NASH; however, the activation of Rab11/PKCδ and PKA/PKCα suggest an activation of membrane insertion pathways as well. Overall these data suggest an altered regulation of protein trafficking in human NASH, although other processes may be involved in the regulation of MRP2 localization.
Collapse
Affiliation(s)
- Anika L Dzierlenga
- Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ, USA
| | | |
Collapse
|
13
|
Guichard A, Jain P, Moayeri M, Schwartz R, Chin S, Zhu L, Cruz-Moreno B, Liu JZ, Aguilar B, Hollands A, Leppla SH, Nizet V, Bier E. Anthrax edema toxin disrupts distinct steps in Rab11-dependent junctional transport. PLoS Pathog 2017; 13:e1006603. [PMID: 28945820 PMCID: PMC5612732 DOI: 10.1371/journal.ppat.1006603] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 08/24/2017] [Indexed: 02/06/2023] Open
Abstract
Various bacterial toxins circumvent host defenses through overproduction of cAMP. In a previous study, we showed that edema factor (EF), an adenylate cyclase from Bacillus anthracis, disrupts endocytic recycling mediated by the small GTPase Rab11. As a result, cargo proteins such as cadherins fail to reach inter-cellular junctions. In the present study, we provide further mechanistic dissection of Rab11 inhibition by EF using a combination of Drosophila and mammalian systems. EF blocks Rab11 trafficking after the GTP-loading step, preventing a constitutively active form of Rab11 from delivering cargo vesicles to the plasma membrane. Both of the primary cAMP effector pathways -PKA and Epac/Rap1- contribute to inhibition of Rab11-mediated trafficking, but act at distinct steps of the delivery process. PKA acts early, preventing Rab11 from associating with its effectors Rip11 and Sec15. In contrast, Epac functions subsequently via the small GTPase Rap1 to block fusion of recycling endosomes with the plasma membrane, and appears to be the primary effector of EF toxicity in this process. Similarly, experiments conducted in mammalian systems reveal that Epac, but not PKA, mediates the activity of EF both in cell culture and in vivo. The small GTPase Arf6, which initiates endocytic retrieval of cell adhesion components, also contributes to junctional homeostasis by counteracting Rab11-dependent delivery of cargo proteins at sites of cell-cell contact. These studies have potentially significant practical implications, since chemical inhibition of either Arf6 or Epac blocks the effect of EF in cell culture and in vivo, opening new potential therapeutic avenues for treating symptoms caused by cAMP-inducing toxins or related barrier-disrupting pathologies. Recent anthrax outbreaks in Zambia and northern Russia and biodefense preparedness highlight the need for new therapies to counteract fatal late-stage pathologies in patients infected with Bacillus anthracis. Indeed, two toxins secreted by this pathogen—edema toxin (ET) and lethal toxin (LT)—can cause death in face of effective antibiotic treatment. ET, a potent adenylate cyclase, severely impacts host cells and tissues through an overproduction of the ubiquitous second messenger cAMP. Previously, we identified Rab11 as a key host factor inhibited by ET. Blockade of Rab11-dependent endocytic recycling resulted in the disruption of intercellular junctions, likely contributing to life threatening vascular effusion observed in anthrax patients. Here we present a multi-system analysis of the mechanism by which EF inhibits Rab11 and exocyst-dependent trafficking. Epistasis experiments in Drosophila reveal that over-activation of the cAMP effectors PKA and Epac/Rap1 interferes with Rab11-mediated trafficking at two distinct steps. We further describe conserved roles of Epac and the small GTPase Arf6 in ET-mediated disruption of vesicular trafficking and show how chemical inhibition of either pathway greatly alleviates ET-induced edema. Thus, our study defines Epac and Arf6 as promising drug targets for the treatment of infectious diseases and other pathologies involving cAMP overload or related barrier disruption.
Collapse
Affiliation(s)
- Annabel Guichard
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, United States of America
| | - Prashant Jain
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, United States of America
| | - Mahtab Moayeri
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, United States of America
| | - Ruth Schwartz
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, United States of America
| | - Stephen Chin
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, United States of America
| | - Lin Zhu
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, United States of America
| | - Beatriz Cruz-Moreno
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, United States of America
| | - Janet Z. Liu
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States of America
| | - Bernice Aguilar
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States of America
- Division of Pediatric Infectious Diseases and the Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, United States of America
| | - Andrew Hollands
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States of America
| | - Stephen H. Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, United States of America
| | - Victor Nizet
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States of America
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Ethan Bier
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, United States of America
- * E-mail:
| |
Collapse
|
14
|
Dzierlenga AL, Clarke JD, Cherrington NJ. Nonalcoholic Steatohepatitis Modulates Membrane Protein Retrieval and Insertion Processes. ACTA ACUST UNITED AC 2016; 44:1799-1807. [PMID: 27604106 DOI: 10.1124/dmd.116.071415] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/25/2016] [Indexed: 01/29/2023]
Abstract
Interindividual variability in drug response in nonalcoholic steatohepatitis (NASH) can be mediated by altered regulation of drug metabolizing enzymes and transporters. Among these is the mislocalization of multidrug resistance-associated protein (MRP2)/Mrp2 away from the canalicular membrane, which results in decreased transport of MRP2/Mrp2 substrates. The exact mechanism of this mislocalization is unknown, although increased activation of membrane retrieval processes may be one possibility. The current study measures the activation status of various mediators implicated in the active membrane retrieval or insertion of membrane proteins to identify which processes may be important in rodent methionine and choline deficient diet-induced NASH. The mediators currently known to be associated with transporter mislocalization are stimulated by oxidative stressors and choleretic stimuli, which play a role in the pathogenesis of NASH. The activation of protein kinases PKA, PKCα, PKCδ, and PKCε and substrates radixin, myristoylated alanine-rich C-kinase substrate, and Rab11 were measured by comparing the expression, phosphorylation, and membrane translocation between control and NASH. Many of the mediators exhibited altered activation in NASH rats. Consistent with membrane retrieval of Mrp2, NASH rats exhibited a decreased phosphorylation of radixin and increased membrane localization of PKCδ and PKCε, thought to be mediators of radixin dephosphorylation. Altered activation of PKCδ, PKA, and PKCα may impair the Rab11-mediated active insertion of Mrp2. Overall, these data suggest alterations in membrane retrieval and insertion processes that may contribute to altered localization of membrane proteins in NASH.
Collapse
Affiliation(s)
- A L Dzierlenga
- Department of Pharmacology & Toxicology, University of Arizona, Tucson, Arizona
| | - J D Clarke
- Department of Pharmacology & Toxicology, University of Arizona, Tucson, Arizona
| | - N J Cherrington
- Department of Pharmacology & Toxicology, University of Arizona, Tucson, Arizona
| |
Collapse
|
15
|
Schonhoff CM, Park SW, Webster CR, Anwer MS. p38 MAPK α and β isoforms differentially regulate plasma membrane localization of MRP2. Am J Physiol Gastrointest Liver Physiol 2016; 310:G999-G1005. [PMID: 27012769 PMCID: PMC4935486 DOI: 10.1152/ajpgi.00005.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/14/2016] [Indexed: 01/31/2023]
Abstract
In hepatocytes, cAMP both activates p38 mitogen-activated protein kinase (MAPK) and increases the amount of multidrug resistance-associated protein-2 (MRP2) in the plasma membrane (PM-MRP2). Paradoxically, taurolithocholate (TLC) activates p38 MAPK but decreases PM-MRP2 in hepatocytes. These opposing effects of cAMP and TLC could be mediated via different p38 MAPK isoforms (α and β) that are activated differentially by upstream kinases (MKK3, MKK4, and MKK6). Thus we tested the hypothesis that p38α MAPK and p38β MAPK mediate increases and decreases in PM-MRP2 by cAMP and TLC, respectively. Studies were conducted in hepatocytes isolated from C57BL/6 wild-type (WT) and MKK3-knockout (MKK3(-/-)) mice and in a hepatoma cell line (HuH7) that overexpresses sodium-taurocholate cotransporting polypeptide (NTCP) (HuH-NTCP). Cyclic AMP activated MKK3, p38 MAPK, and p38α MAPK and increased PM-MRP2 in WT hepatocytes, but failed to activate p38α MAPK or increase PM-MRP2 in MKK3(-/-) hepatocytes. In contrast to cAMP, TLC activated total p38 MAPK but decreased PM-MRP2, and did not activate MKK3 or p38α MAPK in WT hepatocytes. In MKK3(-/-) hepatocytes, TLC still decreased PM-MRP2 and activated p38 MAPK, indicating that these effects are not MKK3-dependent. Additionally, TLC activated MKK6 in MKK3(-/-) hepatocytes, and small interfering RNA knockdown of p38β MAPK abrogated TLC-mediated decreases in PM-MRP2 in HuH-NTCP cells. Taken together, these results suggest that p38α MAPK facilitates plasma membrane insertion of MRP2 by cAMP, whereas p38β MAPK mediates retrieval of PM-MRP2 by TLC.
Collapse
Affiliation(s)
- Christopher M. Schonhoff
- 1Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts; and
| | - Se Won Park
- 1Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts; and
| | - Cynthia R.L. Webster
- 2Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts
| | - M. Sawkat Anwer
- 1Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts; and
| |
Collapse
|
16
|
Hegyi Z, Homolya L. Functional Cooperativity between ABCG4 and ABCG1 Isoforms. PLoS One 2016; 11:e0156516. [PMID: 27228027 PMCID: PMC4882005 DOI: 10.1371/journal.pone.0156516] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/16/2016] [Indexed: 11/18/2022] Open
Abstract
ABCG4 belongs to the ABCG subfamily, the members of which are half transporters composed of a single transmembrane and a single nucleotide-binding domain. ABCG proteins have a reverse domain topology as compared to other mammalian ABC transporters, and have to form functional dimers, since the catalytic sites for ATP binding and hydrolysis, as well as the transmembrane domains are composed of distinct parts of the monomers. Here we demonstrate that ABCG4 can form homodimers, but also heterodimers with its closest relative, ABCG1. Both the full-length and the short isoforms of ABCG1 can dimerize with ABCG4, whereas the ABCG2 multidrug transporter is unable to form a heterodimer with ABCG4. We also show that contrary to that reported in some previous studies, ABCG4 is predominantly localized to the plasma membrane. While both ABCG1 and ABCG4 have been suggested to be involved in lipid transport or regulation, in accordance with our previous results regarding the long version of ABCG1, here we document that the expression of both the short isoform of ABCG1 as well as ABCG4 induce apoptosis in various cell types. This apoptotic effect, as a functional read-out, allowed us to demonstrate that the dimerization between these half transporters is not only a physical interaction but functional cooperativity. Given that ABCG4 is predominantly expressed in microglial-like cells and endothelial cells in the brain, our finding of ABCG4-induced apoptosis may implicate a new role for this protein in the clearance mechanisms within the central nervous system.
Collapse
Affiliation(s)
- Zoltán Hegyi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - László Homolya
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
- * E-mail:
| |
Collapse
|