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Khan OM, Mallardo D, Decock J. Editorial: Cancer genomics in the era of precision medicine. Front Genet 2024; 15:1378917. [PMID: 38435061 PMCID: PMC10904538 DOI: 10.3389/fgene.2024.1378917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 02/08/2024] [Indexed: 03/05/2024] Open
Affiliation(s)
- Omar M. Khan
- College of Health and Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha, Qatar
| | - Domenico Mallardo
- Department of Melanoma, Cancer Immunotherapy and Development Therapeutics INT IRCCS Fondazione “G Pascale”, Napoli, Italy
| | - Julie Decock
- College of Health and Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha, Qatar
- Cancer Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha, Qatar
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Keyan KS, Salim S, Gowda S, Abdelrahman D, Amir SS, Islam Z, Vargas C, Bengoechea-Alonso MT, Alwa A, Dahal S, Kolatkar PR, Da'as S, Torrisani J, Ericsson J, Mohammad F, Khan OM. Control of TGFβ signalling by ubiquitination independent function of E3 ubiquitin ligase TRIP12. Cell Death Dis 2023; 14:692. [PMID: 37863914 PMCID: PMC10589240 DOI: 10.1038/s41419-023-06215-y] [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: 06/19/2023] [Revised: 09/27/2023] [Accepted: 10/05/2023] [Indexed: 10/22/2023]
Abstract
Transforming growth factor β (TGFβ) pathway is a master regulator of cell proliferation, differentiation, and death. Deregulation of TGFβ signalling is well established in several human diseases including autoimmune disorders and cancer. Thus, understanding molecular pathways governing TGFβ signalling may help better understand the underlying causes of some of those conditions. Here, we show that a HECT domain E3 ubiquitin ligase TRIP12 controls TGFβ signalling in multiple models. Interestingly, TRIP12 control of TGFβ signalling is completely independent of its E3 ubiquitin ligase activity. Instead, TRIP12 recruits SMURF2 to SMAD4, which is most likely responsible for inhibitory monoubiquitination of SMAD4, since SMAD4 monoubiquitination and its interaction with SMURF2 were dramatically downregulated in TRIP12-/- cells. Additionally, genetic inhibition of TRIP12 in human and murine cells leads to robust activation of TGFβ signalling which was rescued by re-introducing wildtype TRIP12 or a catalytically inactive C1959A mutant. Importantly, TRIP12 control of TGFβ signalling is evolutionary conserved. Indeed, genetic inhibition of Drosophila TRIP12 orthologue, ctrip, in gut leads to a reduced number of intestinal stem cells which was compensated by the increase in differentiated enteroendocrine cells. These effects were completely normalised in Drosophila strain where ctrip was co-inhibited together with Drosophila SMAD4 orthologue, Medea. Similarly, in murine 3D intestinal organoids, CRISPR/Cas9 mediated genetic targeting of Trip12 enhances TGFβ mediated proliferation arrest and cell death. Finally, CRISPR/Cas9 mediated genetic targeting of TRIP12 in MDA-MB-231 breast cancer cells enhances the TGFβ induced migratory capacity of these cells which was rescued to the wildtype level by re-introducing wildtype TRIP12. Our work establishes TRIP12 as an evolutionary conserved modulator of TGFβ signalling in health and disease.
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Affiliation(s)
- Kripa S Keyan
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Safa Salim
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Swetha Gowda
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | | | - Syeda Sakina Amir
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Zeyaul Islam
- Qatar Biomedical Research Institute, Doha, Qatar
| | - Claire Vargas
- Centre de Recherches en Cancérologie de Toulouse, Université de Toulouse, Inserm, CNRS, Université Toulouse III-Paul Sabatier, Toulouse, France
| | | | - Amira Alwa
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Subrat Dahal
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | | | - Sahar Da'as
- Department of Research, Sidra Medicine, Doha, Qatar
| | - Jerome Torrisani
- Centre de Recherches en Cancérologie de Toulouse, Université de Toulouse, Inserm, CNRS, Université Toulouse III-Paul Sabatier, Toulouse, France
| | - Johan Ericsson
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Farhan Mohammad
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.
| | - Omar M Khan
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.
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Jiménez-Izquierdo R, Morrugares R, Suanes-Cobos L, Correa-Sáez A, Garrido-Rodríguez M, Cerero-Tejero L, Khan OM, de la Luna S, Sancho R, Calzado MA. FBXW7 tumor suppressor regulation by dualspecificity tyrosine-regulated kinase 2. Cell Death Dis 2023; 14:202. [PMID: 36934104 PMCID: PMC10024693 DOI: 10.1038/s41419-023-05724-0] [Citation(s) in RCA: 3] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 02/28/2023] [Accepted: 03/03/2023] [Indexed: 03/20/2023]
Abstract
FBXW7 is a member of the F-box protein family, which functions as the substrate recognition component of the SCF E3 ubiquitin ligase. FBXW7 is a main tumor suppressor due to its ability to control proteasome-mediated degradation of several oncoproteins such as c-Jun, c-Myc, Cyclin E1, mTOR, and Notch1-IC. FBXW7 inactivation in human cancers results from a somatic mutation or downregulation of its protein levels. This work describes a novel regulatory mechanism for FBXW7 dependent on the serine/threonine protein kinase DYRK2. We show that DYRK2 interacts with and phosphorylates FBXW7 resulting in its proteasome-mediated degradation. DYRK2-dependent FBXW7 destabilization is independent of its ubiquitin ligase activity. The functional analysis demonstrates the existence of DYRK2-dependent regulatory mechanisms for key FBXW7 substrates. Finally, we provide evidence indicating that DYRK2-dependent regulation of FBXW7 protein accumulation contributes to cytotoxic effects in response to chemotherapy agents such as Doxorubicin or Paclitaxel in colorectal cancer cell lines and to BET inhibitors in T-cell acute lymphoblastic leukemia cell lines. Altogether, this work reveals a new regulatory axis, DYRK2/FBXW7, which provides an understanding of the role of these two proteins in tumor progression and DNA damage responses.
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Affiliation(s)
- Rafael Jiménez-Izquierdo
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Rosario Morrugares
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Lucía Suanes-Cobos
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Alejandro Correa-Sáez
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Martín Garrido-Rodríguez
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Laura Cerero-Tejero
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Omar M Khan
- Hamad Bin Khalifa University, College of Health and Life Sciences Qatar Foundation, Education City, Doha, Qatar
| | - Susana de la Luna
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), 08003, Barcelona, Spain
- Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010, Barcelona, Spain
| | - Rocío Sancho
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, SE10 9RT, UK
- Department of Medicine III, University Hospital Carl Gustav Carus, Dresden, Germany
| | - Marco A Calzado
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain.
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Córdoba, Spain.
- Hospital Universitario Reina Sofía, Córdoba, Spain.
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Kohil A, Amir SS, Behrens A, Khan OM. A small Rho GTPase RAB25 with a potential role in chemotherapy resistance in pancreatic cancer. Cancer Biomark 2022; 36:133-145. [PMID: 36565104 DOI: 10.3233/cbm-220214] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDA) is one of the major human health challenges with minimal therapeutic benefits due to its late detection, and de novo - and acquired chemotherapy resistance. OBJECTIVE In this work we unravel the potential pro-survival role of RAB25 in pancreatic cancer chemotherapy resistance and aim to identify if RAB25 is a prognostic marker of patients' survival in PDA. METHODS We used RNA sequencing, shRNA mediated gene knockdown, BioGRID open repository of CRISPR screens (ORCS), GEPIA, kmplot.com, and cBioPortal.org databases to identify the role of RAB25 in PDA cell proliferation, chemotherapy response, expression in tumour versus normal tissues, and overall patients' survival. RESULTS RNA sequencing show Rab25 to be one of the top upregulated genes in gemcitabine resistance mouse PDA cells. Knockdown of Rab25 in these cells enhanced gemcitabine toxicity. In addition, re-analysis of previously published CRISPR/Cas9 data confirm RAB25 to be responsible for chemotherapy resistance in KRASG12D mutant human pancreatic cancer cell line. Finally, we used publicly available TCGA datasets and identify the upregulation of RAB25 in tumour tissues compared to the adjacent normal tissue, co-occurrence of KRASG12 mutations with RAB25 amplifications, and poor patients' survival in cohorts with higher mRNA expression of RAB25. CONCLUSION RAB25 expression is a prognostic marker for patient's survival and gemcitabine resistance in PDA.
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Affiliation(s)
- Amira Kohil
- Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Sayeda S Amir
- Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Axel Behrens
- The Francis Crick Institute, London, UK.,Cancer Stem Cell Team, Institute of Cancer Research, London, UK
| | - Omar M Khan
- Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
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Akula MK, Ibrahim MX, Ivarsson EG, Khan OM, Kumar IT, Erlandsson M, Karlsson C, Xu X, Brisslert M, Brakebusch C, Wang D, Bokarewa M, Sayin VI, Bergo MO. Protein prenylation restrains innate immunity by inhibiting Rac1 effector interactions. Nat Commun 2019; 10:3975. [PMID: 31484924 PMCID: PMC6726657 DOI: 10.1038/s41467-019-11606-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 07/23/2019] [Indexed: 12/18/2022] Open
Abstract
Rho family proteins are prenylated by geranylgeranyltransferase type I (GGTase-I), which normally target proteins to membranes for GTP-loading. However, conditional deletion of GGTase-I in mouse macrophages increases GTP-loading of Rho proteins, leading to enhanced inflammatory responses and severe rheumatoid arthritis. Here we show that heterozygous deletion of the Rho family gene Rac1, but not Rhoa and Cdc42, reverses inflammation and arthritis in GGTase-I-deficient mice. Non-prenylated Rac1 has a high affinity for the adaptor protein Ras GTPase-activating-like protein 1 (Iqgap1), which facilitates both GTP exchange and ubiquitination-mediated degradation of Rac1. Consistently, inactivating Iqgap1 normalizes Rac1 GTP-loading, and reduces inflammation and arthritis in GGTase-I-deficient mice, as well as prevents statins from increasing Rac1 GTP-loading and cytokine production in macrophages. We conclude that blocking prenylation stimulates Rac1 effector interactions and unleashes proinflammatory signaling. Our results thus suggest that prenylation normally restrains innate immune responses by preventing Rac1 effector interactions. Macrophage specific deletion of GGTase-I, a prenylation enzyme, in mice induces inflammatory response and rheumatoid arthritis. Here the authors show that GGTase-I deficiency and the resulting reduction of RAC1 prenylation increase RAC1 interaction with the adaptor protein IQGAP1, leading to GTP-loading of RAC1 and enhanced proinflammatory cytokine production.
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Affiliation(s)
- Murali K Akula
- Sahlgrenska Cancer Center, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, SE-405 30, Gothenburg, Sweden.,Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Mohamed X Ibrahim
- Sahlgrenska Cancer Center, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Emil G Ivarsson
- Sahlgrenska Cancer Center, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Omar M Khan
- Adult Stem Cell Laboratory, Francis Crick Research Institute, London, NW1 1AT, UK.,College of Health and Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110, Qatar
| | - Israiel T Kumar
- Sahlgrenska Cancer Center, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Malin Erlandsson
- Department of Rheumatology, Institute of Medicine, University of Gothenburg, SE-41345, Gothenburg, Sweden
| | - Christin Karlsson
- Sahlgrenska Cancer Center, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Xiufeng Xu
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83, Huddinge, Sweden
| | - Mikael Brisslert
- Department of Rheumatology, Institute of Medicine, University of Gothenburg, SE-41345, Gothenburg, Sweden
| | - Cord Brakebusch
- Biotech Research and Innovation Centre, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Donghai Wang
- Department of Immunology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Maria Bokarewa
- Department of Rheumatology, Institute of Medicine, University of Gothenburg, SE-41345, Gothenburg, Sweden
| | - Volkan I Sayin
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, SE-405 30, Gothenburg, Sweden.,Sahlgrenska Cancer Center, Department of Surgery, Institute of Clinical Sciences, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Martin O Bergo
- Sahlgrenska Cancer Center, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, SE-405 30, Gothenburg, Sweden. .,Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83, Huddinge, Sweden.
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Khan OM, Carvalho J, Spencer-Dene B, Mitter R, Frith D, Snijders AP, Wood SA, Behrens A. The deubiquitinase USP9X regulates FBW7 stability and suppresses colorectal cancer. J Clin Invest 2018; 128:1326-1337. [PMID: 29346117 PMCID: PMC5873885 DOI: 10.1172/jci97325] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [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: 09/06/2017] [Accepted: 01/16/2018] [Indexed: 01/03/2023] Open
Abstract
The tumor suppressor FBW7 targets oncoproteins such as c-MYC for ubiquitylation and is mutated in several human cancers. We noted that in a substantial percentage of colon cancers, FBW7 protein is undetectable despite the presence of FBW7 mRNA. To understand the molecular mechanism of FBW7 regulation in these cancers, we employed proteomics and identified the deubiquitinase (DUB) USP9X as an FBW7 interactor. USP9X antagonized FBW7 ubiquitylation, and Usp9x deletion caused Fbw7 destabilization. Mice lacking Usp9x in the gut showed reduced secretory cell differentiation and increased progenitor proliferation, phenocopying Fbw7 loss. In addition, Usp9x inactivation impaired intestinal regeneration and increased tumor burden in colitis-associated intestinal cancer. c-Myc heterozygosity abrogated increased progenitor proliferation and tumor burden in Usp9x-deficient mice, suggesting that Usp9x suppresses tumor formation by regulating Fbw7 protein stability and thereby reducing c-Myc. Thus, we identify a tumor suppressor mechanism in the mammalian intestine that arises from the posttranslational regulation of FBW7 by USP9X independent of somatic FBW7 mutations.
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Affiliation(s)
| | | | | | | | - David Frith
- Proteomics, The Francis Crick Institute, London, United Kingdom
| | | | - Stephen A Wood
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - Axel Behrens
- Adult Stem Cell Laboratory.,King's College London, Faculty of Life Sciences and Medicine, Guy's Campus, London, United Kingdom
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Knezevic NN, Khan OM, Beiranvand A, Candido KD. Repeated Quantitative Urine Toxicology Analysis May Improve Chronic Pain Patient Compliance with Opioid Therapy. Pain Physician 2017; 20:S135-S145. [PMID: 28226335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
BACKGROUND Even though serious efforts have been undertaken by different medical societies to reduce opioid use for treating chronic benign pain, many Americans continue to seek pain relief through opioid consumption. Assuring compliance of these patients may be a difficult aspect of proper management even with regular behavioral monitoring. OBJECTIVE The purpose of this study was to accurately assess the compliance of chronic opioid-consuming patients in an outpatient setting and evaluate if utilizing repeated urine drug testing (UDT) could improve compliance. STUDY DESIGN Retrospective analysis of prospectively collected data. SETTING Outpatient pain management clinic. METHODS After Institutional Review Board (IRB) approval, a retrospective analysis of data for 500 patients was conducted. We included patients who were aged 18 years and older who were treated with opioid analgesic medication for chronic pain. Patients were asked to provide supervised urine toxicology specimens during their regular clinic visits, and were asked to do so without prior notification. The specimens were sent to an external laboratory for quantitative testing using liquid chromatography-tandem mass spectrometry. RESULTS Three hundred and eighty-six (77.2%) patients were compliant with prescribed medications and did not use any illicit drugs or undeclared medications. Forty-one (8.2%) patients tested positive for opioid medication(s) that were not prescribed in our clinic; 8 (1.6%) of the patients were positive for medication that was not prescribed by any physician and was not present in the Illinois Prescription Monitoring Program; 5 (1%) patients tested negative for prescribed opioids; and 60 (12%) patients were positive for illicit drugs (8.6% marijuana, 3.2% cocaine, 0.2% heroin). Repeated UDTs following education and disclosure, showed 49 of the 77 patients (63.6%) had improved compliance. LIMITATIONS This was a single-site study and we normalized concentrations of opioids in urine with creatinine levels while specific gravity normalization was not used. CONCLUSIONS Our results showed that repeated UDT can improve compliance of patients on opioid medications and can improve overall pain management. We believe UDT testing should be used as an important adjunctive tool to help guide clinical decision-making regarding opioid therapy, potentially increasing future quality of care.Key words: Urine toxicology analysis, chronic pain, opioids, compliance, pain management, urine drug testing, urine drug screening.
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Affiliation(s)
- Nebojsa Nick Knezevic
- Vice Chair for Research and Education, Department of Anesthesiology and Pain Management, Advocate Illinois Masonic Medical Center, Clinical Associate Professor of Anesthesiology and Surgery at University of Illinois, Chicago, IL
| | - Omar M Khan
- Dept. of Anesthesiology, Advocate Illinois Masonic Medical Center
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Khan OM, Akula MK, Skålen K, Karlsson C, Ståhlman M, Young SG, Borén J, Bergo MO. Targeting GGTase-I activates RHOA, increases macrophage reverse cholesterol transport, and reduces atherosclerosis in mice. Circulation 2013; 127:782-90. [PMID: 23334894 DOI: 10.1161/circulationaha.112.000588] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Statins have antiinflammatory and antiatherogenic effects that have been attributed to inhibition of RHO protein geranylgeranylation in inflammatory cells. The activity of protein geranylgeranyltransferase type I (GGTase-I) is widely believed to promote membrane association and activation of RHO family proteins. However, we recently showed that knockout of GGTase-I in macrophages activates RHO proteins and proinflammatory signaling pathways, leading to increased cytokine production and rheumatoid arthritis. In this study, we asked whether the increased inflammatory signaling of GGTase-I-deficient macrophages would influence the development of atherosclerosis in low-density lipoprotein receptor-deficient mice. METHODS AND RESULTS Aortic lesions in mice lacking GGTase-I in macrophages (Pggt1b▵/▵) contained significantly more T lymphocytes than the lesions in controls. Surprisingly, however, mean atherosclerotic lesion area in Pggt1b▵/▵ mice was reduced by ≈60%. GGTase-I deficiency reduced the accumulation of cholesterol esters and phospholipids in macrophages incubated with minimally modified and acetylated low-density lipoprotein. Analyses of GGTase-I-deficient macrophages revealed upregulation of the cyclooxygenase 2-peroxisome proliferator-activated-γ pathway and increased scavenger receptor class B type I- and CD36-mediated basal and high-density lipoprotein-stimulated cholesterol efflux. Lentivirus-mediated knockdown of RHOA, but not RAC1 or CDC42, normalized cholesterol efflux. The increased cholesterol efflux in cultured cells was accompanied by high levels of macrophage reverse cholesterol transport and slightly reduced plasma lipid levels in vivo. CONCLUSIONS Targeting GGTase-I activates RHOA and leads to increased macrophage reverse cholesterol transport and reduced atherosclerosis development despite a significant increase in inflammation.
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Affiliation(s)
- Omar M Khan
- Sahlgrenska Cancer Center, Medicinaregatan 1G, Box 425, SE-413 90 Gothenburg, Sweden
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Khan OM, Ibrahim MX, Jonsson IM, Karlsson C, Liu M, Sjogren AKM, Olofsson FJ, Brisslert M, Andersson S, Ohlsson C, Hultén LM, Bokarewa M, Bergo MO. Geranylgeranyltransferase type I (GGTase-I) deficiency hyperactivates macrophages and induces erosive arthritis in mice. J Clin Invest 2011; 121:628-39. [PMID: 21266780 DOI: 10.1172/jci43758] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 11/10/2010] [Indexed: 11/17/2022] Open
Abstract
RHO family proteins are important for the function of inflammatory cells. They are modified with a 20-carbon geranylgeranyl lipid in a process catalyzed by protein geranylgeranyltransferase type I (GGTase-I). Geranylgeranylation is viewed as essential for the membrane targeting and activity of RHO proteins. Consequently, inhibiting GGTase-I to interfere with RHO protein activity has been proposed as a strategy to treat inflammatory disorders. However, here we show that mice lacking GGTase-I in macrophages develop severe joint inflammation resembling erosive rheumatoid arthritis. The disease was initiated by the GGTase-I-deficient macrophages and was transplantable and reversible in bone marrow transplantation experiments. The cells accumulated high levels of active GTP-bound RAC1, CDC42, and RHOA, and RAC1 remained associated with the plasma membrane. Moreover, GGTase-I deficiency activated p38 and NF-κB and increased the production of proinflammatory cytokines. The results challenge the view that geranylgeranylation is essential for the activity and localization of RHO family proteins and suggest that reduced geranylgeranylation in macrophages can initiate erosive arthritis.
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Affiliation(s)
- Omar M Khan
- Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
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Spencer BR, Khan OM, Bobrow BJ, Demaerschalk BM. Emergency medical services support for acute ischemic stroke patients receiving thrombolysis at a primary stroke center. J Brain Dis 2009; 1:13-7. [PMID: 23818804 PMCID: PMC3676336 DOI: 10.4137/jcnsd.s2221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Emergency Medical Services (EMS) is a vital link in the overall chain of stroke survival. A Primary Stroke Center (PSC) relies heavily on the 9-1-1 response system along with the ability of EMS personnel to accurately diagnose acute stroke. Other critical elements include identifying time of symptom onset, providing pre-hospital care, selecting a destination PSC, and communicating estimated time of arrival (ETA). Purpose Our purpose was to evaluate the EMS component of thrombolysed acute ischemic stroke patient care at our PSC. Methods In a retrospective manner we retrieved electronic copies of the EMS incident reports for every thrombolysed ischemic stroke patient treated at our PSC from September 2001 to August 2005. The following data elements were extracted: location of victim, EMS agency, times of dispatch, scene, departure, emergency department (ED) arrival, recordings of time of stroke onset, blood pressure (BP), heart rate (HR), cardiac rhythm, blood glucose (BG), Glasgow Coma Scale (GCS), Cincinnati Stroke Scale (CSS) elements, emergency medical personnel field assessment, and transport decision making. Results Eighty acute ischemic stroke patients received thrombolysis during the study interval. Eighty-one percent arrived by EMS. Two EMS agencies transported to our PSC. Mean dispatch-to-scene time was 6 min, on-scene time was 16 min, transport time was 10 min. Stroke onset time was recorded in 68%, BP, HR, and cardiac rhythm each in 100%, BG in 81%, GCS in 100%, CSS in 100%, and acute stroke diagnosis was made in 88%. Various diagnostic terms were employed: cerebrovascular accident in 40%, unilateral weakness or numbness in 20%, loss of consciousness in 16%, stroke in 8%, other stroke terms in 4%. In 87% of incident reports there was documentation of decision-making to transport to the nearest PSC in conjunction with pre-notification. Conclusion The EMS component of thrombolysed acute ischemic stroke patients care at our PSC appeared to be very good overall. Diagnostic accuracy was excellent, field assessment, decision-making, and transport times were very good. There was still room for improvement in documentation of stroke onset and in employment of a common term for acute stroke.
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