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Assimakopoulou M, Christopoulou ME, Karamani V, Aletras AJ, Gatzounis G. Polycystin-2 Associates With Malignancy in Meningiomas. Appl Immunohistochem Mol Morphol 2023; 31:239-244. [PMID: 36877184 PMCID: PMC10072210 DOI: 10.1097/pai.0000000000001113] [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: 01/08/2022] [Accepted: 09/28/2022] [Indexed: 03/07/2023]
Abstract
The involvement of polycystin-2 (PC2) in cell survival pathways raises questions about its role in carcinogenesis. Aberrant expression of PC2 has been associated with malignancy in various tumors. No evidence exists referring to PC2 expression in meningiomas. The aim of this study was to investigate the expression levels of PC2 in meningiomas and compare them with normal brain samples including leptomeninges. PC2 immunohistochemical expression was quantitatively analyzed in archival tissue from 60 patients with benign (WHO grade 1) and 22 patients with high-grade (21: WHO grade 2 and 1: grade 3) meningiomas. Specifically, the labeling index [the percentage of positive (labeled) cells out of the total number of tumor cells counted] was determined. PC2 mRNA levels were evaluated by quantitative real-time polymerase chain reaction. PC2 immunostaining was not detected in the leptomeninges. Gene expression analysis revealed increased levels of PC2 in WHO grade 1 ( P = 0.008) and WHO grade 2 ( P = 0.0007) meningiomas compared with that of normal brains. PC2 expression was significantly associated with an ascending grade of malignancy by both immunohistochemistry and quantitative real-time polymerase chain reaction ( P < 0.05). Recurrent meningiomas displayed higher levels of PC2 compared with primary meningiomas ( P = 0.008). Although no significant association of PC2 with the overall survival of the patients was found ( P > 0.05), it was noticed that the patients with WHO grade 2 meningiomas with low expression of PC2 survived longer compared with the patients with WHO grade 1 meningioma with high expression of PC2 (mean survival 49.5 and 28 months, respectively). The above results indicate a possible association of PC2 with malignancy in meningiomas. However, the mechanisms underlying PC2 implication in meningioma pathogenesis should be further elucidated.
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Affiliation(s)
| | | | | | - Alexios J. Aletras
- Laboratory of Biochemistry, Department of Chemistry, University of Patras
| | - George Gatzounis
- Department of Neurosurgery, University Hospital of Patras, Patras, Greece
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2
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Rizopoulos T, Assimakopoulou M. Transient receptor potential (TRP) channels in human colorectal cancer: evidence and perspectives. Histol Histopathol 2021; 36:515-526. [PMID: 33528023 DOI: 10.14670/hh-18-308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Colorectal cancer (CRC) is one of the leading causes of death in the civilized world. Transient receptor potential channels (TRPs) are a heterogeneous family of cation channels that play an important role in gastrointestinal physiology. TRPs have been linked with carcinogenesis in the colon and their role as potential therapeutic targets and prognostic biomarkers is under investigation.
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Affiliation(s)
- Theodoros Rizopoulos
- Department of Anatomy, Histology and Embryology, School of Medicine, University of Patras, Patras, Greece
| | - Martha Assimakopoulou
- Department of Anatomy, Histology and Embryology, School of Medicine, University of Patras, Patras, Greece.
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3
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Froghi S, Grant CR, Tandon R, Quaglia A, Davidson B, Fuller B. New Insights on the Role of TRP Channels in Calcium Signalling and Immunomodulation: Review of Pathways and Implications for Clinical Practice. Clin Rev Allergy Immunol 2021; 60:271-292. [PMID: 33405100 PMCID: PMC7985118 DOI: 10.1007/s12016-020-08824-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2020] [Indexed: 12/14/2022]
Abstract
Calcium is the most abundant mineral in the human body and is central to many physiological processes, including immune system activation and maintenance. Studies continue to reveal the intricacies of calcium signalling within the immune system. Perhaps the most well-understood mechanism of calcium influx into cells is store-operated calcium entry (SOCE), which occurs via calcium release-activated channels (CRACs). SOCE is central to the activation of immune system cells; however, more recent studies have demonstrated the crucial role of other calcium channels, including transient receptor potential (TRP) channels. In this review, we describe the expression and function of TRP channels within the immune system and outline associations with murine models of disease and human conditions. Therefore, highlighting the importance of TRP channels in disease and reviewing potential. The TRP channel family is significant, and its members have a continually growing number of cellular processes. Within the immune system, TRP channels are involved in a diverse range of functions including T and B cell receptor signalling and activation, antigen presentation by dendritic cells, neutrophil and macrophage bactericidal activity, and mast cell degranulation. Not surprisingly, these channels have been linked to many pathological conditions such as inflammatory bowel disease, chronic fatigue syndrome and myalgic encephalomyelitis, atherosclerosis, hypertension and atopy.
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Affiliation(s)
- Saied Froghi
- Department of HPB & Liver Transplantation, Royal Free Hospital, Pond St, Hampstead, London, NW3 2QG, UK. .,Division of Surgery & Interventional Sciences/University College London (UCL), Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG, UK. .,HCA Senior Clinical Fellow (HPB & Liver Transplant), Wellington Hospital, St Johns Wood, London, UK.
| | - Charlotte R Grant
- Department of HPB & Liver Transplantation, Royal Free Hospital, Pond St, Hampstead, London, NW3 2QG, UK
| | - Radhika Tandon
- Sheffield Medical School, Beech Hill Road, Sheffield, UK, S10 2RX
| | - Alberto Quaglia
- Department of Pathology, Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG, UK
| | - Brian Davidson
- Department of HPB & Liver Transplantation, Royal Free Hospital, Pond St, Hampstead, London, NW3 2QG, UK.,Division of Surgery & Interventional Sciences/University College London (UCL), Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG, UK
| | - Barry Fuller
- Division of Surgery & Interventional Sciences/University College London (UCL), Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG, UK
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4
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Zhang ZM, Wu XL, Zhang GY, Ma X, He DX. Functional food development: Insights from TRP channels. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.03.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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5
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Yanda MK, Liu Q, Cebotaru V, Guggino WB, Cebotaru L. Histone deacetylase 6 inhibition reduces cysts by decreasing cAMP and Ca 2+ in knock-out mouse models of polycystic kidney disease. J Biol Chem 2017; 292:17897-17908. [PMID: 28887310 DOI: 10.1074/jbc.m117.803775] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/31/2017] [Indexed: 11/06/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is associated with progressive enlargement of multiple renal cysts, often leading to renal failure that cannot be prevented by a current treatment. Two proteins encoded by two genes are associated with ADPKD: PC1 (pkd1), primarily a signaling molecule, and PC2 (pkd2), a Ca2+ channel. Dysregulation of cAMP signaling is central to ADPKD, but the molecular mechanism is unresolved. Here, we studied the role of histone deacetylase 6 (HDAC6) in regulating cyst growth to test the possibility that inhibiting HDAC6 might help manage ADPKD. Chemical inhibition of HDAC6 reduced cyst growth in PC1-knock-out mice. In proximal tubule-derived, PC1-knock-out cells, adenylyl cyclase 6 and 3 (AC6 and -3) are both expressed. AC6 protein expression was higher in cells lacking PC1, compared with control cells containing PC1. Intracellular Ca2+ was higher in PC1-knock-out cells than in control cells. HDAC inhibition caused a drop in intracellular Ca2+ and increased ATP-simulated Ca2+ release. HDAC6 inhibition reduced the release of Ca2+ from the endoplasmic reticulum induced by thapsigargin, an inhibitor of endoplasmic reticulum Ca2+-ATPase. HDAC6 inhibition and treatment of cells with the intracellular Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) reduced cAMP levels in PC1-knock-out cells. Finally, the calmodulin inhibitors W-7 and W-13 reduced cAMP levels, and W-7 reduced cyst growth, suggesting that AC3 is involved in cyst growth regulated by HDAC6. We conclude that HDAC6 inhibition reduces cell growth primarily by reducing intracellular cAMP and Ca2+ levels. Our results provide potential therapeutic targets that may be useful as treatments for ADPKD.
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Affiliation(s)
- Murali K Yanda
- From the Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 and
| | - Qiangni Liu
- From the Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 and
| | - Valeriu Cebotaru
- the Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - William B Guggino
- From the Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 and
| | - Liudmila Cebotaru
- From the Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 and
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6
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Transient receptor potential channel C5 in cancer chemoresistance. Acta Pharmacol Sin 2016; 37:19-24. [PMID: 26657058 DOI: 10.1038/aps.2015.109] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 11/01/2015] [Indexed: 12/25/2022] Open
Abstract
The transient receptor potential (TRP) superfamily contains at least 28 homologs in mammalian. These proteins form TRP channels are permeable to monovalent and divalent cations and participate in a variety of physiological functions. Dysregulation of TRP channels is responsible for numerous diseases. This review provides a brief short overview of mammalian TRP channels with a focus on TRPC5 and its role in cancers. Dysregulation of TRPC5 interrupts Ca(2+) homeostasis in cancer cells, which activates signaling pathways that are highly associated with cancer progression, especially cancer chemoresistance. Based on the important role of TRPC5, we also discuss the potential of TRPC5 as a target for therapeutic intervention. Either direct targeting of TRPC5 or indirect interruption of TRPC5-related signaling pathways may effectively overcome cancer chemoresistance.
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Exploring urinary biomarkers in autosomal dominant polycystic kidney disease. Clin Exp Nephrol 2014; 19:968-73. [PMID: 25543187 DOI: 10.1007/s10157-014-1078-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 12/19/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND Autosomal dominant polycystic kidney disease (ADPKD), the most common inherited kidney disease, is a progressive disease characterized by a bilateral proliferation and enlargement of renal cysts. Recent reports have shown that tolvaptan, a vasopressin V2 receptor antagonist, has been effective in inhibiting renal cyst proliferation and enlargement in ADPKD patients, although no biomarker has identified to predict the effects of tolvaptan. We explored the effective urinary biomarkers in ADPKD in human and in an animal model. METHODS We measured 28 biomarkers in urine taken from ADPKD patients to compare with that of healthy subjects. Next, a gene expression analysis of the kidney from DBA/2FG-pcy mice (ADPKD model animals) was performed to identify prospective biomarkers. Additionally, we investigated the DBA/2FG-pcy mouse urine samples to determine the biomarkers' efficacy. RESULTS There were statistically significant differences in 12 of the 28 prospective urinary biomarkers between urine from ADPKD patients and that from healthy subjects. Six of these matched with highly expressed gene products of DBA/sFG-pcy mouse kidneys. Among those 6 biomarkers, NGAL, M-CSF, and MCP-1 showed significantly higher values in the urine of DBA/2FG-pcy mice than that of wild type. CONCLUSIONS This study suggests that NGAL, M-CSF, MCP-1 are potential candidates of urinary biomarkers in ADPKD.
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Le Corre S, Viau A, Burtin M, El-Karoui K, Cnops Y, Terryn S, Debaix H, Bérissi S, Gubler MC, Devuyst O, Terzi F. Cystic gene dosage influences kidney lesions after nephron reduction. Nephron Clin Pract 2014; 129:42-51. [PMID: 25531116 DOI: 10.1159/000369312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 10/31/2014] [Indexed: 11/19/2022] Open
Abstract
Cystic kidney disease is characterized by the progressive development of multiple fluid-filled cysts. Cysts can be acquired, or they may appear during development or in postnatal life due to specific gene defects and lead to renal failure. The most frequent form of this disease is the inherited polycystic kidney disease (PKD). Experimental models of PKD showed that an increase of cellular proliferation and apoptosis as well as defects in apico-basal and planar cell polarity or cilia play a critical role in cyst development. However, little is known about the mechanisms and the mediators involved in acquired cystic kidney diseases (ACKD). In this study, we used the nephron reduction as a model to study the mechanisms underlying cyst development in ACKD. We found that tubular dilations after nephron reduction recapitulated most of the morphological features of ACKD. The development of tubular dilations was associated with a dramatic increase of cell proliferation. In contrast, the apico-basal polarity and cilia did not seem to be affected. Interestingly, polycystin 1 and fibrocystin were markedly increased and polycystin 2 was decreased in cells lining the dilated tubules, whereas the expression of several other cystic genes did not change. More importantly, Pkd1 haploinsufficiency accelerated the development of tubular dilations after nephron reduction, a phenotype that was associated to a further increase of cell proliferation. These data were relevant to humans ACKD, as cystic genes expression and the rate of cell proliferation were also increased. In conclusion, our study suggests that the nephron reduction can be considered a suitable model to study ACKD and that dosage of genes involved in PKD is also important in ACKD.
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Gao G, Wang W, Tadagavadi RK, Briley NE, Love MI, Miller BA, Reeves WB. TRPM2 mediates ischemic kidney injury and oxidant stress through RAC1. J Clin Invest 2014; 124:4989-5001. [PMID: 25295536 DOI: 10.1172/jci76042] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 09/04/2014] [Indexed: 02/06/2023] Open
Abstract
Ischemia is a leading cause of acute kidney injury. Kidney ischemia is associated with loss of cellular ion homeostasis; however, the pathways that underlie ion homeostasis dysfunction are poorly understood. Here, we evaluated the nonselective cation channel transient receptor potential melastatin 2 (TRPM2) in a murine model of kidney ischemia/reperfusion (I/R) injury. TRPM2-deficient mice were resistant to ischemic injury, as reflected by improved kidney function, reduced histologic damage, suppression of proapoptotic pathways, and reduced inflammation. Moreover, pharmacologic TRPM2 inhibition was also protective against I/R injury. TRPM2 was localized mainly in kidney proximal tubule epithelial cells, and studies in chimeric mice indicated that the effects of TRPM2 are due to expression in parenchymal cells rather than hematopoietic cells. TRPM2-deficient mice had less oxidative stress and lower levels of NADPH oxidase activity after ischemia. While RAC1 is a component of the NADPH oxidase complex, its relation to TRPM2 and kidney ischemic injury is unknown. Following kidney ischemia, TRPM2 promoted RAC1 activation, with active RAC1 physically interacting with TRPM2 and increasing TRPM2 expression at the cell membrane. Finally, inhibition of RAC1 reduced oxidant stress and ischemic injury in vivo. These results demonstrate that TRPM2-dependent RAC1 activation increases oxidant stress and suggest that therapeutic approaches targeting TRPM2 and/or RAC1 may be effective in reducing ischemic kidney injury.
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10
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Allen MD, Qamar S, Vadivelu MK, Sandford RN, Bycroft M. A high-resolution structure of the EF-hand domain of human polycystin-2. Protein Sci 2014; 23:1301-8. [PMID: 24990821 PMCID: PMC4244000 DOI: 10.1002/pro.2513] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 06/25/2014] [Accepted: 06/29/2014] [Indexed: 01/11/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) affects over 1:1000 of the worldwide population and is caused by mutations in two genes, PKD1 and PKD2. PKD2 encodes a 968-amino acid membrane spanning protein, Polycystin-2 (PC-2), which is a member of the TRP ion channel family. The C-terminal cytoplasmic tail contains an EF-hand motif followed by a short coiled-coil domain. We have determined the structure of the EF-hand region of PC-2 using NMR spectroscopy. The use of different boundaries, compared with those used in previous studies, have enabled us to determine a high resolution structure and show that the EF hand motif forms a standard calcium-binding pocket. The affinity of this pocket for calcium has been measured and mutants that both decrease and increase its affinity for the metal ion have been created.
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Affiliation(s)
- Mark D Allen
- MRC Laboratory of Molecular BiologyHills Road, Cambridge, CB2 0QH, United Kingdom
| | - Seema Qamar
- Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of CambridgeCambridge, CB2 0XY, United Kingdom
| | - Murali K Vadivelu
- MRC Laboratory of Molecular BiologyHills Road, Cambridge, CB2 0QH, United Kingdom
| | - Richard N Sandford
- Academic Department of Medical Genetics, School of Clinical Medicine, University of CambridgeCambridge, CB2 0QQ, United Kingdom
| | - Mark Bycroft
- MRC Laboratory of Molecular BiologyHills Road, Cambridge, CB2 0QH, United Kingdom
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11
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Abstract
Membrane proteins remain challenging targets for structural biologists, despite recent technical developments regarding sample preparation and structure determination. We review recent progress towards a structural understanding of TRP channels and the techniques used to that end. We discuss available low-resolution structures from electron microscopy (EM), X-ray crystallography, and nuclear magnetic resonance (NMR) and review the resulting insights into TRP channel function for various subfamily members. The recent high-resolution structure of TRPV1 is discussed in more detail in Chapter 11. We also consider the opportunities and challenges of using the accumulating structural information on TRPs and homologous proteins for deducing full-length structures of different TRP channel subfamilies, such as building homology models. Finally, we close by summarizing the outlook of the "holy grail" of understanding in atomic detail the diverse functions of TRP channels.
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12
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Abstract
The use of medicinal plants or other naturally derived products to relieve illness can be traced back over several millennia, and these natural products are still extensively used nowadays. Studies on natural products have, over the years, enormously contributed to the development of therapeutic drugs used in modern medicine. By means of the use of these substances as selective agonists, antagonists, enzyme inhibitors or activators, it has been possible to understand the complex function of many relevant targets. For instance, in an attempt to understand how pepper species evoke hot and painful actions, the pungent and active constituent capsaicin (from Capsicum sp.) was isolated in 1846 and the receptor for the biological actions of capsaicin was cloned in 1997, which is now known as TRPV1 (transient receptor potential vanilloid 1). Thus, TRPV1 agonists and antagonists have currently been tested in order to find new drug classes to treat different disorders. Indeed, the transient receptor potential (TRP) proteins are targets for several natural compounds, and antagonists of TRPs have been synthesised based on the knowledge of naturally derived products. In this context, this chapter focuses on naturally derived compounds (from plants and animals) that are reported to be able to modulate TRP channels. To clarify and make the understanding of the modulatory effects of natural compounds on TRPs easier, this chapter is divided into groups according to TRP subfamilies: TRPV (TRP vanilloid), TRPA (TRP ankyrin), TRPM (TRP melastatin), TRPC (TRP canonical) and TRPP (TRP polycystin). A general overview on the naturally derived compounds that modulate TRPs is depicted in Table 1.
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Affiliation(s)
- Flavia Carla Meotti
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, SP, Brazil
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Autosomal dominant polycystic kidney disease: recent advances in pathogenesis and potential therapies. Clin Exp Nephrol 2012. [PMID: 23192769 DOI: 10.1007/s10157-012-0741-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is the most common progressive hereditary kidney disease. In 85-90% of cases, ADPKD results from a mutation in the PKD1 gene, and the other 10-15% of the cases are accounted for by mutations in PKD2. PKD1 and PKD2 encode polycystin-1 and polycystin-2. Polycystin-1 may be a receptor that controls the channel activity of polycystin-2 as part of the polycystin signaling complex. ADPKD is characterized by the progressive development of fluid-filled cysts derived from renal tubular epithelial cells that gradually compress the parenchyma and compromise renal function. In recent years, considerable interest has developed in the primary cilia as a site of the proteins that are involved in renal cystogenesis. The pathological processes that facilitate cyst enlargement are hypothesized to result from two specific cellular abnormalities: (1) increased fluid secretion into the cyst lumen and (2) inappropriately increased cell division by the epithelium lining the cyst. Since there is no clinically approved specific or targeted therapy, current practice focuses on blood pressure control and statin therapy to reduce the cardiac mortality associated with chronic kidney disease. However, recent advances in our understanding of the pathways that govern renal cystogenesis have led to a number of intriguing possibilities in regard to therapeutic interventions. The purpose of this article is to review the pathogenesis of renal cyst formation and to review novel targets for the treatment of ADPKD.
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Mekahli D, Parys JB, Bultynck G, Missiaen L, De Smedt H. Polycystins and cellular Ca2+ signaling. Cell Mol Life Sci 2012; 70:2697-712. [PMID: 23076254 PMCID: PMC3708286 DOI: 10.1007/s00018-012-1188-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 10/01/2012] [Accepted: 10/02/2012] [Indexed: 12/19/2022]
Abstract
The cystic phenotype in autosomal dominant polycystic kidney disease is characterized by a profound dysfunction of many cellular signaling patterns, ultimately leading to an increase in both cell proliferation and apoptotic cell death. Disturbance of normal cellular Ca2+ signaling seems to be a primary event and is clearly involved in many pathways that may lead to both types of cellular responses. In this review, we summarize the current knowledge about the molecular and functional interactions between polycystins and multiple components of the cellular Ca2+-signaling machinery. In addition, we discuss the relevant downstream responses of the changed Ca2+ signaling that ultimately lead to increased proliferation and increased apoptosis as observed in many cystic cell types.
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Affiliation(s)
- D. Mekahli
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
| | - Jan B. Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
| | - G. Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
| | - L. Missiaen
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
| | - H. De Smedt
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
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15
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Spirli C, Locatelli L, Fiorotto R, Morell CM, Fabris L, Pozzan T, Strazzabosco M. Altered store operated calcium entry increases cyclic 3',5'-adenosine monophosphate production and extracellular signal-regulated kinases 1 and 2 phosphorylation in polycystin-2-defective cholangiocytes. Hepatology 2012; 55:856-68. [PMID: 21987453 PMCID: PMC3272110 DOI: 10.1002/hep.24723] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
UNLABELLED Mutations in polycystins (PC1 or PC2/TRPP2) cause progressive polycystic liver disease (PLD). In PC2-defective mice, cyclic 3',5'-adenosine monophosphate/ protein kinase A (cAMP/PKA)-dependent activation of extracellular signal-regulated kinase/ mammalian target of rapamycin (ERK-mTOR) signaling stimulates cyst growth. We investigated the mechanisms connecting PC2 dysfunction to altered Ca(2+) and cAMP production and inappropriate ERK signaling in PC2-defective cholangiocytes. Cystic cholangiocytes were isolated from PC2 conditional-KO (knockout) mice (Pkd2(flox/-) :pCxCreER™; hence, called Pkd2KO) and compared to cholangiocytes from wild-type mice (WT). Our results showed that, compared to WT cells, in PC2-defective cholangiocytes (Pkd2KO), cytoplasmic and ER-Ca(2+) (measured with Fura-2 and Mag-Fluo4) levels are decreased and store-operated Ca(2+) entry (SOCE) is inhibited, whereas the expression of Ca(2+) -sensor stromal interaction molecule 1 (STIM1) and store-operated Ca(2+) channels (e.g., the Orai1 channel) are unchanged. In Pkd2KO cells, ER-Ca(2+) depletion increases cAMP and PKA-dependent ERK1/2 activation and both are inhibited by STIM1 inhibitors or by silencing of adenylyl cyclase type 6 (AC6). CONCLUSION These data suggest that PC2 plays a key role in SOCE activation and inhibits the STIM-dependent activation of AC6 by ER Ca(2+) depletion. In PC2-defective cells, the interaction of STIM-1 with Orai channels is uncoupled, whereas coupling to AC6 is maximized. The resulting overproduction of cAMP, in turn, potently activates the PKA/ERK pathway. PLD, because of PC2 deficiency, represents the first example of human disease linked to the inappropriate activation of store-operated cAMP production.
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Affiliation(s)
- Carlo Spirli
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
| | - Luigi Locatelli
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
- Dept. of Clinical Medicine and Prevention University of Milan-Bicocca, Monza, Italy
| | - Romina Fiorotto
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
| | - Carola M. Morell
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- Dept. of Clinical Medicine and Prevention University of Milan-Bicocca, Monza, Italy
| | - Luca Fabris
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
- Department of Gastroenterological Sciences, University of Padova, Padova, Italy
| | - Tullio Pozzan
- Consiglio Nazionale delle Ricerche, Neuroscience Institute, Dept. of Biomedical Sciences, University of Padova and Venetian Institute of Molecular Medicine, Padova, Italy
| | - Mario Strazzabosco
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
- Dept. of Clinical Medicine and Prevention University of Milan-Bicocca, Monza, Italy
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Berrout J, Jin M, O'Neil RG. Critical role of TRPP2 and TRPC1 channels in stretch-induced injury of blood-brain barrier endothelial cells. Brain Res 2011; 1436:1-12. [PMID: 22192412 DOI: 10.1016/j.brainres.2011.11.044] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 11/14/2011] [Accepted: 11/19/2011] [Indexed: 12/23/2022]
Abstract
The microvessels of the brain are very sensitive to mechanical stresses such as observed in traumatic brain injury (TBI). Such stresses can quickly lead to dysfunction of the microvessel endothelial cells, including disruption of blood-brain barrier (BBB). It is now evident that elevation of cytosolic calcium levels ([Ca2+]i) can compromise the BBB integrity, however the mechanism by which mechanical injury can produce a [Ca2+]i increase in brain endothelial cells is unclear. To assess the effects of mechanical/stretch injury on [Ca2+]i signaling, mouse brain microvessel endothelial cells (bEnd3) were grown to confluency on elasticized membranes and [Ca2+]i monitored using fura 2 fluorescence imaging. Application of an injury, using a pressure/stretch pulse of 50 ms, induced a rapid transient increase in [Ca2+]i. In the absence of extracellular Ca2+, the injury-induced [Ca2+]i transient was greatly reduced, but not fully eliminated, while unloading of Ca2+ stores by thapsigargin treatment in the absence of extracellular Ca2+ abolished the injury transient. Application of LOE-908 and amiloride, TRPC and TRPP2 channel blockers, respectively, both reduced the transient [Ca2+]i increase. Further, siRNA knockdown assays directed at TRPC1 and TRPP2 expression also resulted in a reduction of the injury-induced [Ca2+]i response. In addition, stretch injury induced increases of NO production and actin stress fiber formation, both of which were markedly reduced upon treatment with LOE908 and/or amiloride. We conclude that mechanical injury of brain endothelial cells induces a rapid influx of calcium, mediated by TRPC1 and TRPP2 channels, which leads to NO synthesis and actin cytoskeletal rearrangement.
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Affiliation(s)
- Jonathan Berrout
- Department of Integrative Biology & Pharmacology, The University of Texas Health Science Center, Houston, TX 77030, USA
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17
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Sumoza-Toledo A, Lange I, Cortado H, Bhagat H, Mori Y, Fleig A, Penner R, Partida-Sánchez S. Dendritic cell maturation and chemotaxis is regulated by TRPM2-mediated lysosomal Ca2+ release. FASEB J 2011; 25:3529-42. [PMID: 21753080 DOI: 10.1096/fj.10-178483] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Chemokines induce calcium (Ca(2+)) signaling and chemotaxis in dendritic cells (DCs), but the molecular players involved in shaping intracellular Ca(2+) changes remain to be characterized. Using siRNA and knockout mice, we show that in addition to inositol 1,4,5-trisphosphate (IP(3))-mediated Ca(2+) release and store-operated Ca(2+) entry (SOCE), the transient receptor potential melastatin 2 (TRPM2) channel contributes to Ca(2+) release but not Ca(2+) influx in mouse DCs. Consistent with these findings, TRPM2 expression in DCs is restricted to endolysosomal vesicles, whereas in neutrophils, the channel localizes to the plasma membrane. TRPM2-deficient DCs show impaired maturation and severely compromised chemokine-activated directional migration as well as bacterial-induced DC trafficking to the draining lymph nodes. Defective DC chemotaxis is due to perturbed chemokine-receptor-initiated Ca(2+) signaling mechanisms, which include suppression of TRPM2-mediated Ca(2+) release and secondary modification of SOCE. DCs deficient in both TRPM2 and IP(3) receptor signaling lose their ability to perform chemotaxis entirely. These results highlight TRPM2 as a key player regulating DC chemotaxis through its function as Ca(2+) release channel and confirm ADP-ribose as a novel second messenger for intracellular Ca(2+) mobilization.
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Affiliation(s)
- Adriana Sumoza-Toledo
- Laboratory of Cell and Molecular Signaling, Center for Biomedical Research, Queen's Medical Center, Honolulu, Hawaii, USA
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18
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Takiar V, Caplan MJ. Polycystic kidney disease: pathogenesis and potential therapies. Biochim Biophys Acta Mol Basis Dis 2010; 1812:1337-43. [PMID: 21146605 DOI: 10.1016/j.bbadis.2010.11.014] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 11/23/2010] [Accepted: 11/26/2010] [Indexed: 10/18/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a prevalent, inherited condition for which there is currently no effective specific clinical therapy. The disease is characterized by the progressive development of fluid-filled cysts derived from renal tubular epithelial cells which gradually compress the parenchyma and compromise renal function. Current interests in the field focus on understanding and exploiting signaling mechanisms underlying disease pathogenesis as well as delineating the role of the primary cilium in cystogenesis. This review highlights the pathogenetic pathways underlying renal cyst formation as well as novel therapeutic targets for the treatment of PKD. This article is part of a Special Issue entitled: Polycystic Kidney Disease.
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Affiliation(s)
- Vinita Takiar
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
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19
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Boucher CA, Ward HH, Case RL, Thurston KS, Li X, Needham A, Romero E, Hyink D, Qamar S, Roitbak T, Powell S, Ward C, Wilson PD, Wandinger-Ness A, Sandford RN. Receptor protein tyrosine phosphatases are novel components of a polycystin complex. Biochim Biophys Acta Mol Basis Dis 2010; 1812:1225-38. [PMID: 21126580 DOI: 10.1016/j.bbadis.2010.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 11/16/2010] [Accepted: 11/19/2010] [Indexed: 12/27/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutation of PKD1 and PKD2 that encode polycystin-1 and polycystin-2. Polycystin-1 is tyrosine phosphorylated and modulates multiple signaling pathways including AP-1, and the identity of the phosphatases regulating polycystin-1 are previously uncharacterized. Here we identify members of the LAR protein tyrosine phosphatase (RPTP) superfamily as members of the polycystin-1complex mediated through extra- and intracellular interactions. The first extracellular PKD1 domain of polycystin-1 interacts with the first Ig domain of RPTPσ, while the polycystin-1 C-terminus of polycystin-1 interacts with the regulatory D2 phosphatase domain of RPTPγ. Additional homo- and heterotypic interactions between RPTPs recruit RPTPδ. The multimeric polycystin protein complex is found localised in cilia. RPTPσ and RPTPδ are also part of a polycystin-1/E-cadherin complex known to be important for early events in adherens junction stabilisation. The interaction between polycystin-1 and RPTPγ is disrupted in ADPKD cells, while RPTPσ and RPTPδ remain closely associated with E-cadherin, largely in an intracellular location. The polycystin-1 C-terminus is an in vitro substrate of RPTPγ, which dephosphorylates the c-Src phosphorylated Y4237 residue and activates AP1-mediated transcription. The data identify RPTPs as novel interacting partners of the polycystins both in cilia and at adhesion complexes and demonstrate RPTPγ phosphatase activity is central to the molecular mechanisms governing polycystin-dependent signaling. This article is part of a Special Issue entitled: Polycystic Kidney Disease.
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Affiliation(s)
- Catherine A Boucher
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 2XY, UK
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20
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Fu Y, Kim I, Lian P, Li A, Zhou L, Li C, Liang D, Coffey RJ, Ma J, Zhao P, Zhan Q, Wu G. Loss of Bicc1 impairs tubulomorphogenesis of cultured IMCD cells by disrupting E-cadherin-based cell-cell adhesion. Eur J Cell Biol 2010; 89:428-36. [PMID: 20219263 PMCID: PMC2886128 DOI: 10.1016/j.ejcb.2010.01.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 01/20/2010] [Accepted: 01/28/2010] [Indexed: 01/12/2023] Open
Abstract
The Bicaudal-C (Bic-C) gene was originally discovered in Drosophila melanogaster. The gene product Bic-C is thought to serve as an RNA-binding molecule targeting diverse proteins at the post-transcriptional level. Recent research has shown this gene to be conserved in many species, from Caenorhabditis elegans to humans. Disruption of this protein can disturb the normal migration direction of the anterior follicle cell of Drosophila oocytes, while mutation of a mouse Bicc1 (a mouse homologue of Bic-C) results in phenotypes mimicking human hereditary polycystic kidney disease (PKD). However, the cellular function of Bicc1 gene products in mammalian systems remains largely unknown. In this study, we established stable IMCD (mouse inner medullary collecting duct) cell lines, in which Bicc1 was silenced by short hairpin RNA inhibition (shRNA). We show that inhibition of Bicc1 disrupted normal tubulomorphogenesis and induced cystogenesis of IMCD cells grown in three dimensional cultures. To determine what factors contributed to the defect, we systematically examined biological changes of Bicc1-silenced IMCD cells. We found that the cells had significant defects in E-cadherin-based cell-cell adhesion, along with abnormalities in actin cytoskeleton organization, cell-extracellular matrix interactions, cell proliferation, and apoptosis. These findings suggest that lack of Bicc1 leads to disruption of normal cell-cell junctions, which in turn impedes establishment of epithelial polarity. These cellular defects may initiate abnormal tubulomorphogenesis and cystogenesis of IMCD cells grown in vitro. The observation of aberrant cellular behaviors in Bicc1-silenced IMCD cells reveal functions for Bicc1 in renal epithelial cells and provides insight into a potential pathogenic mechanism of polycystic kidney disease.
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Affiliation(s)
- Yulong Fu
- Division of Translational Cancer Research and Therapy, State Key Laboratory of Molecular Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences, Beijing 100021, China
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21
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Kim I, Ding T, Fu Y, Li C, Cui L, Li A, Lian P, Liang D, Wang DW, Guo C, Ma J, Zhao P, Coffey RJ, Zhan Q, Wu G. Conditional mutation of Pkd2 causes cystogenesis and upregulates beta-catenin. J Am Soc Nephrol 2009; 20:2556-69. [PMID: 19939939 DOI: 10.1681/asn.2009030271] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Loss of polycystin-2 (PC2) in mice (Pkd2(-/-)) results in total body edema, focal hemorrhage, structural cardiac defects, abnormal left-right axis, hepatorenal and pancreatic cysts, and embryonic lethality. The molecular mechanisms by which loss of PC2 leads to these phenotypes remain unknown. We generated a model to allow targeted Pkd2 inactivation using the Cre-loxP system. Global inactivation of Pkd2 produced a phenotype identical to Pkd2(-/-) mice with undetectable PC2 protein and perinatal lethality. Using various Cre mouse lines, we found that kidney, pancreas, or time-specific deletion of Pkd2 led to cyst formation. In addition, we developed an immortalized renal collecting duct cell line with inactive Pkd2; these cells had aberrant cell-cell contact, ciliogenesis, and tubulomorphogenesis. They also significantly upregulated beta-catenin, axin2, and cMyc. Our results suggest that loss of PC2 disrupts normal behavior of renal epithelial cells through dysregulation of beta-catenin-dependent signaling, revealing a potential role for this signaling pathway in PC2-associated ADPKD.
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Affiliation(s)
- Ingyu Kim
- Division of Genetic Medicine, Department of Medicine and Cell and Developmental Biology, Vanderbilt University, 2215 Garland Avenue, Nashville, TN 37232, USA
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22
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Kim I, Li C, Liang D, Chen XZ, Coffy RJ, Ma J, Zhao P, Wu G. Polycystin-2 expression is regulated by a PC2-binding domain in the intracellular portion of fibrocystin. J Biol Chem 2008; 283:31559-66. [PMID: 18782757 DOI: 10.1074/jbc.m805452200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Autosomal dominant (ADPKD) and autosomal recessive (ARPKD) polycystic kidney disease are caused by mutations in Pkd1/Pkd2 and Pkhd1, which encode polycystins (PCs) and fibrocystin/polyductin (FPC). Our recent study reported that a deficiency in FPC increases the severity of cystic disease in Pkd2 mutants and down-regulates PC2 in vivo, but the precise molecular mechanism of these effects is unknown (Kim, I., Fu, Y., Hui, K., Moeckel, G., Mai, W., Li, C., Liang, D., Zhao, P., Ma, J., Chen, X.-Z., George, A. L., Jr., Coffey, R. J., Feng, Z. P., and Wu, G. (2008) J. Am. Soc. Nephrol. 19, 455-468). In this study, through the use of deletion and mutagenesis strategies, we identified a PC2-binding domain in the intracellular C terminus of FPC and an FPC-binding domain in the intracellular N terminus of PC2. These binding domains provide a molecular basis for the physical interaction between PC2 and FPC. In addition, we also found that physical interaction between the binding domains of PC2 and FPC is able to prevent down-regulation of PC2 induced by loss of FPC. In vivo, we generated a mouse model of ADPKD with hypomorphic Pkd2 alleles (Pkd2nf3/nf3) and show that PC2 down-regulation is accompanied by a phenotype similar to that of Pkhd1(-/-) mice. These findings demonstrate a common mechanism underlying cystogenesis in ADPKD and ARPKD and provide insight into the molecular relationship between PC2 and FPC.
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Affiliation(s)
- Ingyu Kim
- Departmentof Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
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23
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Shimizu T, Janssens A, Voets T, Nilius B. Regulation of the murine TRPP3 channel by voltage, pH, and changes in cell volume. Pflugers Arch 2008; 457:795-807. [PMID: 18663466 DOI: 10.1007/s00424-008-0558-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 07/08/2008] [Accepted: 07/10/2008] [Indexed: 01/10/2023]
Abstract
Transient receptor potential (TRP) polycystin 3 (TRPP3) is a member of the TRP superfamily of cation channels. Murine TRPP3 has been reported to form an acid-activated cation channel on the plasma membrane when coexpressed with the polycystin 1-like protein 3 (PKD1L3); however, the function and biophysical properties of TRPP3-dependent channels have not yet been characterized in detail. Here we show that overexpression of murine TRPP3 channel in HEK293 cells, without coexpression of PDK1-like proteins, leads to robust channel activity. These channels exhibit a high single-channel conductance of 184 pS at negative potentials, are Ca2+-permeable, and relatively nonselective between cations. Whole-cell experiments showed a characteristic form of voltage-dependent gating of TRPP3 channels, whereby repolarization after depolarization caused large transient inward TRPP3 tail currents. Moreover, we found that TRPP3 activity was increased upon cell swelling and by alkalization. Taken together, our results demonstrate that TRPP3, on its own, can act as a voltage-dependent, pH- and volume-sensitive plasma membrane cation channel.
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Affiliation(s)
- Takahiro Shimizu
- Department of Molecular Cell Biology, Laboratory of Ion Channel Research, Katholieke Universiteit Leuven, Campus Gasthuisberg, Herestraat 49, Bus 802, B-3000, Leuven, Belgium
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24
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Kim I, Fu Y, Hui K, Moeckel G, Mai W, Li C, Liang D, Zhao P, Ma J, Chen XZ, George AL, Coffey RJ, Feng ZP, Wu G. Fibrocystin/polyductin modulates renal tubular formation by regulating polycystin-2 expression and function. J Am Soc Nephrol 2008; 19:455-68. [PMID: 18235088 DOI: 10.1681/asn.2007070770] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Autosomal recessive polycystic kidney disease is caused by mutations in PKHD1, which encodes the membrane-associated receptor-like protein fibrocystin/polyductin (FPC). FPC associates with the primary cilia of epithelial cells and co-localizes with the Pkd2 gene product polycystin-2 (PC2), suggesting that these two proteins may function in a common molecular pathway. For investigation of this, a mouse model with a gene-targeted mutation in Pkhd1 that recapitulates phenotypic characteristics of human autosomal recessive polycystic kidney disease was produced. The absence of FPC is associated with aberrant ciliogenesis in the kidneys of Pkhd1-deficient mice. It was found that the COOH-terminus of FPC and the NH2-terminus of PC2 interact and that lack of FPC reduced PC2 expression but not vice versa, suggesting that PC2 may function immediately downstream of FPC in vivo. PC2-channel activities were dysregulated in cultured renal epithelial cells derived from Pkhd1 mutant mice, further supporting that both cystoproteins function in a common pathway. In addition, mice with mutations in both Pkhd1 and Pkd2 had a more severe renal cystic phenotype than mice with single mutations, suggesting that FPC acts as a genetic modifier for disease severity in autosomal dominant polycystic kidney disease that results from Pkd2 mutations. It is concluded that a functional and molecular interaction exists between FPC and PC2 in vivo.
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Affiliation(s)
- Ingyu Kim
- Division of Genetic Medicine, Department of Medicine and Cell and Developmental Biology, Vanderbilt University, 539 LH, 2215 Garland Avenue, Nashville, TN 37232, USA
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25
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Reaves BJ, Wolstenholme AJ. The TRP channel superfamily: insights into how structure, protein-lipid interactions and localization influence function. Biochem Soc Trans 2007; 35:77-80. [PMID: 17233605 DOI: 10.1042/bst0350077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
TRP (transient receptor potential) cationic channels are key molecules that are involved in a variety of diverse biological processes ranging from fertility to osmosensation and nociception. Increasing our knowledge of these channels will help us to understand a range of physiological and pathogenic processes, as well as highlighting potential therapeutic drug targets. The founding members of the TRP family, Drosophila TRP and TRPL (TRP-like) proteins, were identified within the last two decades and there has been a subsequent explosion in the number and type of TRP channel described. Although information is accumulating as to the function of some of the TRP channels, the activation and inactivation mechanisms, structure, and interacting proteins of many, if not most, are awaiting elucidation. The Cell and Molecular Biology of TRP Channels Meeting held at the University of Bath included speakers working on a number of the different subfamilies of TRP channels and provided a basis for highlighting both similarities and differences between these groups. As the TRP channels mediate diverse functions, this meeting also brought together an audience with wide-ranging research interests, including biochemistry, cell biology, physiology and neuroscience, and inspired lively discussion on the issues reviewed herein.
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Affiliation(s)
- B J Reaves
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK.
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