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Li S, Luo Z, Meng S, Qiu X, Zheng F, Dai W, Zhang X, Sui W, Yan Q, Tang D, Dai Y. Label-free quantitative proteomic and phosphoproteomic analyses of renal biopsy tissues in membranous nephropathy. Proteomics Clin Appl 2021; 16:e2000069. [PMID: 34543527 DOI: 10.1002/prca.202000069] [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: 09/02/2020] [Revised: 09/01/2021] [Accepted: 09/17/2021] [Indexed: 11/11/2022]
Abstract
PURPOSE Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults. However, the underlying mechanisms of its occurrence and development are not completely clear. Thus, it is essential to explore the mechanisms. EXPERIMENTAL DESIGN Here, we employed label-free quantification and liquid chromatography-tandem mass spectrometry analysis techniques to investigate the proteomic and phosphoproteomic alterations in renal biopsy tissues of MN patients. Samples were collected from 16 MN patients and 10 controls. Immunohistochemistry (IHC) was performed to validate the hub phosphoprotein. RESULTS We focused on the changes in the phosphoproteome in MN group versus control group (CG). Totally, 1704 phosphoproteins containing 3241 phosphosites were identified and quantified. The phosphorylation levels of 216 phosphoproteins containing 297 phosphosites were differentially regulated in stage II MN group versus CG, and 333 phosphoproteins containing 461 phosphosites were differentially phosphorylated in stage III MN group versus CG. In each comparison, several differential phosphoproteins were factors, kinases and receptors involved in cellular processes, biological regulation and other biological processes. The subcellular location of most of the differential phosphoproteins was the nucleus. Protein-protein interaction analysis showed that the connections among the differential phosphoproteins were extremely complex, and several signalling pathways probably associated with MN were identified. The hub phosphoprotein was validated by IHC. CONCLUSIONS AND CLINICAL RELEVANCE This investigation can provide direct insight into the global phosphorylation events in MN group versus CG and may help to shed light on the potential pathogenic mechanisms of MN.
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Affiliation(s)
- Shanshan Li
- Clinical Medical Research Center, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China
| | - Zhifeng Luo
- Guangxi Key Laboratory of Metabolic Disease Research, Department of Nephrology, The No. 924 Hospital of the Joint Logistic Support Force of the Chinese People's Liberation Army, Guilin, China
| | - Shuhui Meng
- Clinical Medical Research Center, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China
| | - Xiaofen Qiu
- Clinical Medical Research Center, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China.,Guangxi Key Laboratory of Metabolic Disease Research, Department of Nephrology, The No. 924 Hospital of the Joint Logistic Support Force of the Chinese People's Liberation Army, Guilin, China
| | - Fengping Zheng
- Clinical Medical Research Center, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China
| | - Weier Dai
- College of Natural Science, University of Texas at Austin, Austin, Texas, USA
| | - Xinzhou Zhang
- Clinical Medical Research Center, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China
| | - Weiguo Sui
- Guangxi Key Laboratory of Metabolic Disease Research, Department of Nephrology, The No. 924 Hospital of the Joint Logistic Support Force of the Chinese People's Liberation Army, Guilin, China
| | - Qiang Yan
- Guangxi Key Laboratory of Metabolic Disease Research, Department of Nephrology, The No. 924 Hospital of the Joint Logistic Support Force of the Chinese People's Liberation Army, Guilin, China
| | - Donge Tang
- Clinical Medical Research Center, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China
| | - Yong Dai
- Clinical Medical Research Center, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China
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Role of Rho GTPase Interacting Proteins in Subcellular Compartments of Podocytes. Int J Mol Sci 2021; 22:ijms22073656. [PMID: 33915776 PMCID: PMC8037304 DOI: 10.3390/ijms22073656] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/22/2021] [Accepted: 03/26/2021] [Indexed: 01/15/2023] Open
Abstract
The first step of urine formation is the selective filtration of the plasma into the urinary space at the kidney structure called the glomerulus. The filtration barrier of the glomerulus allows blood cells and large proteins such as albumin to be retained while eliminating the waste products of the body. The filtration barrier consists of three layers: fenestrated endothelial cells, glomerular basement membrane, and podocytes. Podocytes are specialized epithelial cells featured by numerous, actin-based projections called foot processes. Proteins on the foot process membrane are connected to the well-organized intracellular actin network. The Rho family of small GTPases (Rho GTPases) act as intracellular molecular switches. They tightly regulate actin dynamics and subsequent diverse cellular functions such as adhesion, migration, and spreading. Previous studies using podocyte-specific transgenic or knockout animal models have established that Rho GTPases are crucial for the podocyte health and barrier function. However, little attention has been paid regarding subcellular locations where distinct Rho GTPases contribute to specific functions. In the current review, we discuss cellular events involving the prototypical Rho GTPases (RhoA, Rac1, and Cdc42) in podocytes, with particular focus on the subcellular compartments where the signaling events occur. We also provide our synthesized views of the current understanding and propose future research directions.
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3
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Révész C, Wasik AA, Godó M, Tod P, Lehtonen S, Szénási G, Hamar P. Cold Saline Perfusion before Ischemia-Reperfusion Is Harmful to the Kidney and Is Associated with the Loss of Ezrin, a Cytoskeletal Protein, in Rats. Biomedicines 2021; 9:biomedicines9010030. [PMID: 33401597 PMCID: PMC7824567 DOI: 10.3390/biomedicines9010030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 12/27/2020] [Accepted: 12/28/2020] [Indexed: 11/30/2022] Open
Abstract
Background: Organ protection for transplantation is perfusion with ice-cold preservation solutions, although saline is also used in animal experiments and living donor transplantations. However, ice-cold perfusion can contribute to initial graft injury. Our aim was to test if cytoskeletal damage of parenchymal cells is caused by saline itself or by the ice-cold solution. Methods: F344 rat kidneys were flushed with cold (4 °C) saline, ischemic and sham kidneys were not perfused. In a separate set, F344 kidneys were flushed with saline or preservation solution at 4 or 15 °C. Ischemia time was 30 min. Results: Renal injury was significantly more severe following cold ischemia (CI) than after ischemia-reperfusion without flushing (ischemia/reperfusion (I/R)). Functional and morphologic damage was accompanied by severe loss of ezrin from glomerular and tubular epithelial cells after CI. Moreover, saline caused serious injury independently from its temperature, while the perfusion solution was more beneficial, especially at 4 °C. Conclusions: Flushing the kidney with ice-cold saline can cause more severe injury than ischemia-reperfusion at body temperature even during a short (30 min) ischemia. Saline perfusion can prolong recovery from ischemia in kidney transplantation, which can be prevented by using preservation solutions.
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Affiliation(s)
- Csaba Révész
- Institute of Translational Medicine, Faculty of Medicine, Semmelweis University, 1143 Budapest, Hungary; (C.R.); (M.G.); (P.T.); (G.S.)
| | - Anita A. Wasik
- Department of Pathology, Faculty of Medicine, University of Helsinki, FIN-00014 Helsinki, Finland; (A.A.W.); (S.L.)
| | - Mária Godó
- Institute of Translational Medicine, Faculty of Medicine, Semmelweis University, 1143 Budapest, Hungary; (C.R.); (M.G.); (P.T.); (G.S.)
| | - Pál Tod
- Institute of Translational Medicine, Faculty of Medicine, Semmelweis University, 1143 Budapest, Hungary; (C.R.); (M.G.); (P.T.); (G.S.)
| | - Sanna Lehtonen
- Department of Pathology, Faculty of Medicine, University of Helsinki, FIN-00014 Helsinki, Finland; (A.A.W.); (S.L.)
- Research Program for Clinical and Molecular Metabolism, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Gábor Szénási
- Institute of Translational Medicine, Faculty of Medicine, Semmelweis University, 1143 Budapest, Hungary; (C.R.); (M.G.); (P.T.); (G.S.)
| | - Péter Hamar
- Institute of Translational Medicine, Faculty of Medicine, Semmelweis University, 1143 Budapest, Hungary; (C.R.); (M.G.); (P.T.); (G.S.)
- Correspondence: ; Tel.: +36-20-825-9751; Fax: +36-1-210-0100
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4
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Hughes MR, Canals Hernaez D, Cait J, Refaeli I, Lo BC, Roskelley CD, McNagny KM. A sticky wicket: Defining molecular functions for CD34 in hematopoietic cells. Exp Hematol 2020; 86:1-14. [PMID: 32422232 DOI: 10.1016/j.exphem.2020.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/05/2020] [Accepted: 05/09/2020] [Indexed: 02/06/2023]
Abstract
The CD34 cell surface antigen is widely expressed in tissues on cells with progenitor-like properties and on mature vascular endothelia. In adult human bone marrow, CD34 marks hematopoietic stem and progenitor cells (HSPCs) starting from the bulk of hematopoietic stem cells with long-term repopulating potential (LT-HSCs) throughout expansion and differentiation of oligopotent and unipotent progenitors. CD34 protein surface expression is typically lost as cells mature into terminal effectors. Because of this expression pattern of HSPCs, CD34 has had a central role in the evaluation or selection of donor graft tissue in HSC transplant (HSCT). Given its clinical importance, it is surprising that the biological functions of CD34 are still poorly understood. This enigma is due, in part, to CD34's context-specific role as both a pro-adhesive and anti-adhesive molecule and its potential functional redundancy with other sialomucins. Moreover, there are also critical differences in the regulation of CD34 expression on HSPCs in humans and experimental mice. In this review, we highlight some of the more well-defined functions of CD34 in HSPCs with a focus on proposed functions most relevant to HSCT biology.
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Affiliation(s)
- Michael R Hughes
- The Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Diana Canals Hernaez
- The Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Jessica Cait
- The Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Ido Refaeli
- The Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Bernard C Lo
- The Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Calvin D Roskelley
- Life Sciences Institute, Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Kelly M McNagny
- The Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada.
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5
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Schwarz A, Möller-Hackbarth K, Ebarasi L, Unnersjö Jess D, Zambrano S, Blom H, Wernerson A, Lal M, Patrakka J. Coro2b, a podocyte protein downregulated in human diabetic nephropathy, is involved in the development of protamine sulphate-induced foot process effacement. Sci Rep 2019; 9:8888. [PMID: 31221975 PMCID: PMC6586875 DOI: 10.1038/s41598-019-45303-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 05/31/2019] [Indexed: 12/15/2022] Open
Abstract
Podocytes have an important role in the pathogenesis of diabetic nephropathy (DN). Podocyte foot process effacement, mediated largely by the actin-based cytoskeleton of foot processes, is commonly detected in DN and is believed to be a key pathogenic event in the development of proteinuria. In this study, we identified coronin 2b (Coro2b), a member of known actin-regulating proteins, the coronins, as a highly podocyte-enriched molecule located at the cytoplasmic side of the apical plasma membrane. Studies in human renal biopsies show that glomerular Coro2b expression is significantly down-regulated in patients with DN. Studies in knockout mice indicate that Coro2b is not required for the development or maintenance of the glomerular filtration barrier. Moreover, inactivation of Coro2b specifically in podocytes does not affect the outcome of nephropathy in a streptozotocin-induced diabetes model. However, Coro2b seems to modulate the reorganization of foot processes under pathological conditions as Coro2b knockout podocytes are partially protected from protamine sulfate perfusion-induced foot process effacement. Taken together, our study suggests a role for Coro2b in the pathogenesis of glomerulopathies. Further studies regarding the involvement of Coro2b in podocyte health and diseases are warranted.
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Affiliation(s)
- Angelina Schwarz
- Karolinska Institutet/AstraZeneca Integrated Cardio Metabolic Centre, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Katja Möller-Hackbarth
- Karolinska Institutet/AstraZeneca Integrated Cardio Metabolic Centre, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Lwaki Ebarasi
- Karolinska Institutet/AstraZeneca Integrated Cardio Metabolic Centre, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - David Unnersjö Jess
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Solna, Sweden
| | - Sonia Zambrano
- Karolinska Institutet/AstraZeneca Integrated Cardio Metabolic Centre, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Hans Blom
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Solna, Sweden
| | - Annika Wernerson
- Division of Renal Medicine, Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Mark Lal
- Bioscience, Cardiovascular, Renal and Metabolism, Innovative Medicines Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Jaakko Patrakka
- Karolinska Institutet/AstraZeneca Integrated Cardio Metabolic Centre, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.
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Yin LM, Duan TT, Ulloa L, Yang YQ. Ezrin Orchestrates Signal Transduction in Airway Cells. Rev Physiol Biochem Pharmacol 2019; 174:1-23. [PMID: 28702704 DOI: 10.1007/112_2017_4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ezrin is a critical structural protein that organizes receptor complexes and orchestrates their signal transduction. In this study, we review the ezrin-meditated regulation of critical receptor complexes, including the epidermal growth factor receptor (EGFR), CD44, vascular cell adhesion molecule (VCAM), and the deleted in colorectal cancer (DCC) receptor. We also analyze the ezrin-meditated regulation of critical pathways associated with asthma, such as the RhoA, Rho-associated protein kinase (ROCK), and protein kinase A (cAMP/PKA) pathways. Mounting evidence suggests that ezrin plays a role in controlling airway cell function and potentially contributes to respiratory diseases. Ezrin can participate in asthma pathogenesis by affecting bronchial epithelium repair, T lymphocyte regulation, and the contraction of the airway smooth muscle cells. These studies provide new insights for the design of novel therapeutic strategies for asthma treatment.
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Affiliation(s)
- Lei-Miao Yin
- Laboratory of Molecular Biology, Shanghai Research Institute of Acupuncture and Meridian, Yue Yang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200030, China
| | - Ting-Ting Duan
- Laboratory of Molecular Biology, Shanghai Research Institute of Acupuncture and Meridian, Yue Yang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200030, China
| | - Luis Ulloa
- Laboratory of Molecular Biology, Shanghai Research Institute of Acupuncture and Meridian, Yue Yang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200030, China. .,Department of Surgery, Center of Immunology and Inflammation, Rutgers-New Jersey Medical School, Rutgers University, Newark, NJ, 07101, USA.
| | - Yong-Qing Yang
- Laboratory of Molecular Biology, Shanghai Research Institute of Acupuncture and Meridian, Yue Yang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200030, China.
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7
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Abstract
Ezrin is highly expressed in glomerular podocytes and is reported to form a multi-protein complex with scaffold protein Na+/H+ exchanger regulatory factor 2 (NHERF2) and podocalyxin, a major sialoprotein. Podocalyxin-knockout mice died within 24 h of birth with anuric renal failure, whereas NHERF2-knockout mice show no apparent changes in the glomerular functions. However, the physiological roles of ezrin in glomerular podocytes remain unclear. Here, we investigated the importance of ezrin in the regulation of glomerular podocyte function using ezrin-knockdown mice (Vil2 kd/kd ). The Vil2 kd/kd mice did not exhibit apparent glomerular dysfunction, morphological defects or abnormal localisation of podocalyxin and NHERF2 in podocytes. Thus, we investigated the influence of ezrin defects on Rho-GTPase activity, as ezrin interacts with the Rho-GTPase dissociation inhibitor (Rho-GDI), which plays a key role in the regulation of podocyte actin organisation. In Vil2 kd/kd glomeruli, Rac1 activity was significantly reduced compared to wildtype (WT) glomeruli at baseline. Furthermore, Vil2 kd/kd mice showed reduced susceptibility to glomerular injury. In WT glomeruli, Rac1 activity was enhanced in nephrotic conditions, but remained at baseline levels in Vil2 kd/kd glomeruli, suggesting that loss of ezrin protects podocytes from injury-induced morphological changes by suppressing Rac1 activation.
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8
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Kang HG, Lee M, Lee KB, Hughes M, Kwon BS, Lee S, McNagny KM, Ahn YH, Ko JM, Ha IS, Choi M, Cheong HI. Loss of podocalyxin causes a novel syndromic type of congenital nephrotic syndrome. Exp Mol Med 2017; 49:e414. [PMID: 29244787 PMCID: PMC5750479 DOI: 10.1038/emm.2017.227] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/01/2017] [Accepted: 07/11/2017] [Indexed: 01/09/2023] Open
Abstract
Many cellular structures directly imply specific biological functions. For example, normal slit diaphragm structures that extend from podocyte foot processes ensure the filtering function of renal glomeruli. These slits are covered by a number of surface proteins, such as nephrin, podocin, podocalyxin and CD2AP. Here we report a human patient presenting with congenital nephrotic syndrome, omphalocele and microcoria due to two loss-of-function mutations in PODXL, which encodes podocalyxin, inherited from each parent. This set of symptoms strikingly mimics previously reported mouse Podxl−/− embryos, emphasizing the essential function of PODXL in mammalian kidney development and highlighting this patient as a human PODXL-null model. The results underscore the utility of current genomics approaches to provide insights into the genetic mechanisms of human disease traits through molecular diagnosis.
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Affiliation(s)
- Hee Gyung Kang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea.,Research Coordination Center for Rare Diseases, Seoul National University Hospital, Seoul, Republic of Korea
| | - Moses Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kyoung Boon Lee
- Department of Pathology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Michael Hughes
- The Biomedical Research Centre, The University of British Colombia, Vancouver, British Columbia, Canada
| | - Bo Sang Kwon
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sangmoon Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kelly M McNagny
- The Biomedical Research Centre, The University of British Colombia, Vancouver, British Columbia, Canada
| | - Yo Han Ahn
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea.,Research Coordination Center for Rare Diseases, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jung Min Ko
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea.,Research Coordination Center for Rare Diseases, Seoul National University Hospital, Seoul, Republic of Korea
| | - Il-Soo Ha
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea.,Kidney Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Murim Choi
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Kidney Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hae Il Cheong
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea.,Research Coordination Center for Rare Diseases, Seoul National University Hospital, Seoul, Republic of Korea.,Kidney Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
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9
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Kusumoto H, Shintani Y, Kanzaki R, Kawamura T, Funaki S, Minami M, Nagatomo I, Morii E, Okumura M. Podocalyxin influences malignant potential by controlling epithelial-mesenchymal transition in lung adenocarcinoma. Cancer Sci 2017; 108:528-535. [PMID: 28004467 PMCID: PMC5378270 DOI: 10.1111/cas.13142] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/28/2016] [Accepted: 12/18/2016] [Indexed: 12/13/2022] Open
Abstract
Epithelial-mesenchymal transition (EMT) plays an important role in the progression of lung carcinoma. Podocalyxin (PODXL), which belongs to the CD34 family and regulates cell morphology, has been linked to EMT in lung cancer, and PODXL overexpression is associated with poor prognosis in several different classes of cancers. The aim of this study was to clarify the role of PODXL overexpression in EMT in lung cancer, and to determine the prognostic value of PODXL overexpression in tumors from lung cancer patients. The morphology, EMT marker expression, and migration and invasion abilities of engineered A549 PODXL-knockdown (KD) or PODXL-overexpression (OE) lung adenocarcinoma cells were examined. PODXL expression levels were assessed by immunohistochemistry in 114 human clinical lung adenocarcinoma specimens and correlated with clinical outcomes. PODXL-KD cells were epithelial in shape, whereas PODXL-OE cells displayed mesenchymal morphology. Epithelial markers were upregulated in PODXL-KD cells and downregulated in PODXL-OE cells, whereas mesenchymal markers were downregulated in the former and upregulated in the latter. A highly selective inhibitor of phosphatidylinositol 3-kinase-Akt signaling attenuated EMT of PODXL-OE cells, while a transforming growth factor inhibitor did not, suggesting that PODXL induces EMT of lung adenocarcinoma cells via the phosphatidylinositol 3-kinase pathway. In lung adenocarcinoma clinical specimens, PODXL expression was detected in minimally invasive and invasive adenocarcinoma, but not in non-invasive adenocarcinoma. Disease free survival and cancer-specific survival were significantly worse for patients whose tumors overexpressed PODXL. PODXL overexpression induces EMT in lung adenocarcinoma and contributes to tumor progression.
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Affiliation(s)
- Hidenori Kusumoto
- Department of General Thoracic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.,Department of Pathology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yasushi Shintani
- Department of General Thoracic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Ryu Kanzaki
- Department of General Thoracic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tomohiro Kawamura
- Department of General Thoracic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Soichiro Funaki
- Department of General Thoracic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Masato Minami
- Department of General Thoracic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Izumi Nagatomo
- Department of Respiratory Medicine, Allergy and Rheumatic Disease, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Eiichi Morii
- Department of Pathology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Meinoshin Okumura
- Department of General Thoracic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
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10
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Abstract
Podocytes are highly specialized cells of the kidney glomerulus that wrap around capillaries and that neighbor cells of the Bowman’s capsule. When it comes to glomerular filtration, podocytes play an active role in preventing plasma proteins from entering the urinary ultrafiltrate by providing a barrier comprising filtration slits between foot processes, which in aggregate represent a dynamic network of cellular extensions. Foot processes interdigitate with foot processes from adjacent podocytes and form a network of narrow and rather uniform gaps. The fenestrated endothelial cells retain blood cells but permit passage of small solutes and an overlying basement membrane less permeable to macromolecules, in particular to albumin. The cytoskeletal dynamics and structural plasticity of podocytes as well as the signaling between each of these distinct layers are essential for an efficient glomerular filtration and thus for proper renal function. The genetic or acquired impairment of podocytes may lead to foot process effacement (podocyte fusion or retraction), a morphological hallmark of proteinuric renal diseases. Here, we briefly discuss aspects of a contemporary view of podocytes in glomerular filtration, the patterns of structural changes in podocytes associated with common glomerular diseases, and the current state of basic and clinical research.
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Affiliation(s)
- Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
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11
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The cell surface mucin podocalyxin regulates collective breast tumor budding. Breast Cancer Res 2016; 18:11. [PMID: 26796961 PMCID: PMC4722710 DOI: 10.1186/s13058-015-0670-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/31/2015] [Indexed: 01/10/2023] Open
Abstract
Background Overexpression of the transmembrane sialomucin podocalyxin, which is known to play a role in lumen formation during polarized epithelial morphogenesis, is an independent indicator of poor prognosis in a number of epithelial cancers, including those that arise in the breast. Therefore, we set out to determine if podocalyxin plays a functional role in breast tumor progression. Methods MCF-7 breast cancer cells, which express little endogenous podocalyxin, were stably transfected with wild type podocalyxin for forced overexpression. 4T1 mammary tumor cells, which express considerable endogenous podocalyxin, were retrovirally transduced with a short hairpin ribonucleic acid (shRNA) targeting podocalyxin for stable knockdown. In vitro, the effects of podocalyxin on collective cellular migration and invasion were assessed in two-dimensional monolayer and three-dimensional basement membrane/collagen gel culture, respectively. In vivo, local invasion was assessed after orthotopic transplantation in immunocompromised mice. Results Forced overexpression of podocalyxin caused cohesive clusters of epithelial MCF-7 breast tumor cells to bud off from the primary tumor and collectively invade the stroma of the mouse mammary gland in vivo. This budding was not associated with any obvious changes in histoarchitecture, matrix deposition or proliferation in the primary tumour. In vitro, podocalyxin overexpression induced a collective migration of MCF-7 tumor cells in two-dimensional (2-D) monolayer culture that was dependent on the activity of the actin scaffolding protein ezrin, a cytoplasmic binding partner of podocalyxin. In three-dimensional (3-D) culture, podocalyxin overexpression induced a collective budding and invasion that was dependent on actomyosin contractility. Interestingly, the collectively invasive cell aggregates often contained expanded microlumens that were also observed in vivo. Conversely, when endogenous podocalyxin was removed from highly metastatic, but cohesive, 4T1 mammary tumor cells there was a decrease in collective invasion in three-dimensional culture. Conclusions Podocalyxin is a tumor cell-intrinsic regulator of experimental collective tumor cell invasion and tumor budding. Electronic supplementary material The online version of this article (doi:10.1186/s13058-015-0670-4) contains supplementary material, which is available to authorized users.
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12
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Bryant DM, Roignot J, Datta A, Overeem AW, Kim M, Yu W, Peng X, Eastburn DJ, Ewald AJ, Werb Z, Mostov KE. A molecular switch for the orientation of epithelial cell polarization. Dev Cell 2014; 31:171-87. [PMID: 25307480 DOI: 10.1016/j.devcel.2014.08.027] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 06/30/2014] [Accepted: 08/28/2014] [Indexed: 11/27/2022]
Abstract
The formation of epithelial tissues containing lumens requires not only the apical-basolateral polarization of cells, but also the coordinated orientation of this polarity such that the apical surfaces of neighboring cells all point toward the central lumen. Defects in extracellular matrix (ECM) signaling lead to inverted polarity so that the apical surfaces face the surrounding ECM. We report a molecular switch mechanism controlling polarity orientation. ECM signals through a β1-integrin/FAK/p190RhoGAP complex to downregulate a RhoA/ROCK/Ezrin pathway at the ECM interface. PKCβII phosphorylates the apical identity-promoting Podocalyxin/NHERF1/Ezrin complex, removing Podocalyxin from the ECM-abutting cell surface and initiating its transcytosis to an apical membrane initiation site for lumen formation. Inhibition of this switch mechanism results in the retention of Podocalyxin at the ECM interface and the development instead of collective front-rear polarization and motility. Thus, ECM-derived signals control the morphogenesis of epithelial tissues by controlling the collective orientation of epithelial polarization.
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Affiliation(s)
- David M Bryant
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Julie Roignot
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Anirban Datta
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Arend W Overeem
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Minji Kim
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Wei Yu
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Xiao Peng
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Dennis J Eastburn
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Andrew J Ewald
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Zena Werb
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Keith E Mostov
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158-2140, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158-2140, USA.
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Peng XH, Liang PY, Ou SJ, Zu XB. Protective effect of pioglitazone on kidney injury in diabetic rats. ASIAN PAC J TROP MED 2014; 7:819-22. [DOI: 10.1016/s1995-7645(14)60143-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/15/2014] [Accepted: 09/15/2014] [Indexed: 10/24/2022] Open
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14
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GIV/Girdin is a central hub for profibrogenic signalling networks during liver fibrosis. Nat Commun 2014; 5:4451. [PMID: 25043713 PMCID: PMC4107319 DOI: 10.1038/ncomms5451] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 06/18/2014] [Indexed: 01/18/2023] Open
Abstract
Progressive liver fibrosis is characterized by the deposition of collagen by activated hepatic stellate cells (HSCs). Activation of HSCs is a multiple receptor-driven process in which profibrotic signals are enhanced, and anti-fibrotic pathways are suppressed. Here we report the discovery of a novel signaling platform comprised of G protein subunit, Gαi and GIV, its guanine exchange factor (GEF), which serves as a central hub within the fibrogenic signalling network initiated by diverse classes of receptors. GIV is expressed in the liver after fibrogenic injury and is required for HSC activation. Once expressed, GIV enhances the profibrotic (PI3K-Akt-FoxO1 and TGFβ-SMAD) and inhibits the anti-fibrotic (cAMP-PKA-pCREB) pathways to skew the signalling network in favor of fibrosis, all via activation of Gαi. We also provide evidence that GIV may serve as a biomarker for progression of fibrosis after liver injury and a therapeutic target for arresting and/or reversing HSC activation during liver fibrosis.
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15
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Exome sequencing and in vitro studies identified podocalyxin as a candidate gene for focal and segmental glomerulosclerosis. Kidney Int 2013; 85:124-33. [PMID: 24048372 PMCID: PMC4068013 DOI: 10.1038/ki.2013.354] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 06/25/2013] [Accepted: 07/25/2013] [Indexed: 01/20/2023]
Abstract
Our understanding of focal and segmental glomerulosclerosis (FSGS) has advanced significantly from the studies of rare, monogenic forms of the disease. These studies have demonstrated the critical roles of multiple aspects of podocyte function in maintaining glomerular function. A substantial body of research has suggested that the integral membrane protein podocalyxin (PODXL) is required for proper function of podocytes, possibly by preserving the patency of the slit diaphragm by negative charge-based repulsion. Exome sequencing of affected cousins from an autosomal dominant pedigree with FSGS identified a co-segregating private variant, PODXL p.L442R, affecting the transmembrane region of the protein. Of the remaining 11 shared gene variants, two segregated with disease but their gene products were not detected in the glomerulus. In comparison to wild type, this disease-segregating PODXL variant facilitated dimerization. By contrast, this change does not alter protein stability, extracellular domain glycosylation, cell surface expression, global subcellular localization, or interaction with its intracellular binding partner ezrin. Thus, a variant form of PODXL remains the most likely candidate causing FSGS in one family with autosomal dominant inheritance, but its full effect on protein function remains unknown. Our work highlights the challenge faced in the clinical interpretation of whole exome data for small pedigrees with autosomal dominant diseases.
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16
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Fu P, Yang Z, Bach LA. Prohibitin-2 binding modulates insulin-like growth factor-binding protein-6 (IGFBP-6)-induced rhabdomyosarcoma cell migration. J Biol Chem 2013; 288:29890-900. [PMID: 24003225 DOI: 10.1074/jbc.m113.510826] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Insulin-like growth factor (IGF)-binding protein (IGFBP)-6 decreases cancer cell proliferation and survival by inhibiting the effects of IGF-II. More recently, IGFBP-6 was found to promote the migration of rhabdomyosarcoma (RMS) cells in an IGF-independent manner, and MAPK pathways were involved in this process. However, the precise molecular mechanisms of these IGF-independent migratory actions of IGFBP-6 are largely unknown. Here, we report that prohibitin-2 (PHB2), a single-span membrane protein, is a key regulator of IGFBP-6-induced RMS cell migration. PHB2 and IGFBP-6 co-localize on the RMS cell surface, and they specifically interact, as demonstrated by affinity chromatography, co-immunoprecipitation, biosensor analysis, and confocal microscopy. Binding affinities for PHB2 are 9.0 ± 1.0 nM for IGFBP-6 and 10.2 ± 0.5 nM for mIGFBP-6, a non-IGF-binding mutant of IGFBP-6. The C-domain but not the N-domain of IGFBP-6 is involved in PHB2 binding. In addition, IGFBP-6 indirectly increases PHB2 tyrosine phosphorylation on RMS membranes. Importantly, PHB2 knockdown completely abolished IGFBP-6-mediated RMS cell migration. In contrast, IGFBP-6-induced MAPK pathway activation was not affected, suggesting that PHB2 may act as a downstream effector of these pathways. These results indicate that PHB2 plays a key role in this IGF-independent action of IGFBP-6 and suggest a possible therapeutic target for RMS.
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Affiliation(s)
- Ping Fu
- From the Department of Medicine, Central Clinical School, Monash University, Alfred Medical Research and Education Precinct, Prahran, Victoria 3181, Australia and
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