1
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Saqib U, Demaree IS, Obukhov AG, Baig MS, Khan MS, Altwaijry N, Nasution MAF, Mizuguchi K, Hajela K. Structural and accessibility studies highlight the differential binding of clemizole to TRPC5 and TRPC6. J Biomol Struct Dyn 2024:1-14. [PMID: 38279926 DOI: 10.1080/07391102.2024.2306198] [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: 10/10/2023] [Accepted: 01/07/2024] [Indexed: 01/29/2024]
Abstract
Transient Receptor Potential Canonical 5 (T RP C5) and T RP C6 channels play critical physiological roles in various cell types. Their involvement in numerous disease progression mechanisms has led to extensive searches for their inhibitors. Although several potent T RP C inhibitors have been developed and the structure of their binding sites were mapped using cryo electron microscopy, a comprehensive understanding of the molecular interactions within the inhibitor binding site of T RP Cs remains elusive. This study aimed to decipher the structural determinants and molecular mechanisms contributing to the differential binding of clemizole to T RP C5 and T RP C6, with a particular focus on the accessibility of binding site residues. This information can help better understand what molecular features allow for selective binding, which is a key characteristic of clinically effective pharmacological agents. Using computational methodologies, we conducted an in-depth molecular docking analysis of clemizole with T RP C5 and T RP C6 channels. The protein structures were retrieved from publicly accessible protein databases. Discovery Studio 2020 Client Visualizer and Chimera software facilitated our in-silico mutation experiments and enabled us to identify the critical structural elements influencing clemizole binding. Our study reveals key molecular determinants at the clemizole binding site, specifically outlining the role of residues' Accessible Surface Area (ASA) and Relative Accessible Surface Area (RASA) in differential binding. We found that lower accessibility of T RP C6 binding site residues, compared to those in T RP C5, could account for the lower affinity binding of clemizole to T RP C6. This work illuminates the pivotal role of binding site residue accessibility in determining the affinity of clemizole to T RP C5 and T RP C6. A nuanced understanding of the distinct binding properties between these homologous proteins may pave the way for the development of more selective inhibitors, promising improved therapeutic efficacy and fewer off-target effects. By demystifying the structural and molecular subtleties of T RP C inhibitors, this research could significantly accelerate the drug discovery process, offering hope to patients afflicted with T RP C-related diseases.
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Affiliation(s)
- Uzma Saqib
- School of Life Sciences, Devi Ahilya Vishwavidyalaya, Indore, MP, India
| | - Isaac S Demaree
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Alexander G Obukhov
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Mirza S Baig
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India
| | - Mohd Shahnawaz Khan
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Nojood Altwaijry
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Mochammad Arfin Fardiansyah Nasution
- Institute for Protein Research, Osaka University, Osaka, Japan
- Artificial Intelligence Center for Health and Biomedical Research, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - Kenji Mizuguchi
- Institute for Protein Research, Osaka University, Osaka, Japan
- Artificial Intelligence Center for Health and Biomedical Research, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - Krishnan Hajela
- School of Life Sciences, Devi Ahilya Vishwavidyalaya, Indore, MP, India
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2
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Staruschenko A, Ma R, Palygin O, Dryer SE. Ion channels and channelopathies in glomeruli. Physiol Rev 2023; 103:787-854. [PMID: 36007181 PMCID: PMC9662803 DOI: 10.1152/physrev.00013.2022] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/15/2022] [Accepted: 08/21/2022] [Indexed: 11/22/2022] Open
Abstract
An essential step in renal function entails the formation of an ultrafiltrate that is delivered to the renal tubules for subsequent processing. This process, known as glomerular filtration, is controlled by intrinsic regulatory systems and by paracrine, neuronal, and endocrine signals that converge onto glomerular cells. In addition, the characteristics of glomerular fluid flow, such as the glomerular filtration rate and the glomerular filtration fraction, play an important role in determining blood flow to the rest of the kidney. Consequently, disease processes that initially affect glomeruli are the most likely to lead to end-stage kidney failure. The cells that comprise the glomerular filter, especially podocytes and mesangial cells, express many different types of ion channels that regulate intrinsic aspects of cell function and cellular responses to the local environment, such as changes in glomerular capillary pressure. Dysregulation of glomerular ion channels, such as changes in TRPC6, can lead to devastating glomerular diseases, and a number of channels, including TRPC6, TRPC5, and various ionotropic receptors, are promising targets for drug development. This review discusses glomerular structure and glomerular disease processes. It also describes the types of plasma membrane ion channels that have been identified in glomerular cells, the physiological and pathophysiological contexts in which they operate, and the pathways by which they are regulated and dysregulated. The contributions of these channels to glomerular disease processes, such as focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy, as well as the development of drugs that target these channels are also discussed.
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Affiliation(s)
- Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida
- Hypertension and Kidney Research Center, University of South Florida, Tampa, Florida
- James A. Haley Veterans Hospital, Tampa, Florida
| | - Rong Ma
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Oleg Palygin
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Stuart E Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, Texas
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Hagmann H, Khayyat NH, Oezel C, Papadakis A, Kuczkowski A, Benzing T, Gulbins E, Dryer S, Brinkkoetter PT. Paraoxonase 2 (PON2) Deficiency Reproduces Lipid Alterations of Diabetic and Inflammatory Glomerular Disease and Affects TRPC6 Signaling. Cells 2022; 11:cells11223625. [PMID: 36429053 PMCID: PMC9688324 DOI: 10.3390/cells11223625] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/31/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022] Open
Abstract
Diabetes and inflammatory diseases are associated with an altered cellular lipid composition due to lipid peroxidation. The pathogenic potential of these lipid alterations in glomerular kidney diseases remains largely obscure as suitable cell culture and animal models are lacking. In glomerular disease, a loss of terminally differentiated glomerular epithelial cells called podocytes refers to irreversible damage. Podocytes are characterized by a complex ramified cellular architecture and highly active transmembrane signaling. Alterations in lipid composition in states of disease have been described in podocytes but the pathophysiologic mechanisms mediating podocyte damage are unclear. In this study, we employ a genetic deletion of the anti-oxidative, lipid-modifying paraoxonase 2 enzyme (PON2) as a model to study altered cellular lipid composition and its effects on cellular signaling in glomerular disease. PON2 deficiency reproduces features of an altered lipid composition of glomerular disease, characterized by an increase in ceramides and cholesterol. PON2 knockout mice are more susceptible to glomerular damage in models of aggravated oxidative stress such as adriamycin-induced nephropathy. Voltage clamp experiments in cultured podocytes reveal a largely increased TRPC6 conductance after a membrane stretch in PON2 deficiency. Correspondingly, a concomitant knockout of TRPC6 and PON2 partially rescues the aggravated glomerular phenotype of a PON2 knockout in the adriamycin model. This study establishes PON2 deficiency as a model to investigate the pathophysiologic mechanisms of podocyte dysfunction related to alterations in the lipid composition, as seen in diabetic and inflammatory glomerular disease. Expanding the knowledge on these routes and options of intervention could lead to novel treatment strategies for glomerular disease.
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Affiliation(s)
- Henning Hagmann
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
- Correspondence:
| | | | - Cem Oezel
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
| | - Antonios Papadakis
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
- Institute for Genetics, Faculty of Mathematics and Natural Sciences, University of Cologne, 50931 Cologne, Germany
| | - Alexander Kuczkowski
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol), 50931 Cologne, Germany
| | - Erich Gulbins
- Department of Molecular Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany
| | - Stuart Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, TX 77204, USA
| | - Paul T. Brinkkoetter
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, 50931 Cologne, Germany
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4
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Chai XN, Ludwig FA, Müglitz A, Gong Y, Schaefer M, Regenthal R, Krügel U. A Pharmacokinetic and Metabolism Study of the TRPC6 Inhibitor SH045 in Mice by LC-MS/MS. Int J Mol Sci 2022; 23:ijms23073635. [PMID: 35408998 PMCID: PMC8998618 DOI: 10.3390/ijms23073635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/17/2022] [Accepted: 03/24/2022] [Indexed: 12/10/2022] Open
Abstract
TRPC6, the sixth member of the family of canonical transient receptor potential (TRP) channels, contributes to a variety of physiological processes and human pathologies. This study extends the knowledge on the newly developed TRPC6 blocker SH045 with respect to its main target organs beyond the description of plasma kinetics. According to the plasma concentration-time course in mice, SH045 is measurable up to 24 h after administration of 20 mg/kg BW (i.v.) and up to 6 h orally. The short plasma half-life and rather low oral bioavailability are contrasted by its reported high potency. Dosage limits were not worked out, but absence of safety concerns for 20 mg/kg BW supports further dose exploration. The disposition of SH045 is described. In particular, a high extravascular distribution, most prominent in lung, and a considerable renal elimination of SH045 were observed. SH045 is a substrate of CYP3A4 and CYP2A6. Hydroxylated and glucuronidated metabolites were identified under optimized LC-MS/MS conditions. The results guide a reasonable selection of dose and application route of SH045 for target-directed preclinical studies in vivo with one of the rare high potent and subtype-selective TRPC6 inhibitors available.
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Affiliation(s)
- Xiao-Ning Chai
- Rudolf Boehm Institute for Pharmacology and Toxicology, Leipzig University, 04107 Leipzig, Germany; (X.-N.C.); (A.M.); (Y.G.); (M.S.)
| | - Friedrich-Alexander Ludwig
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318 Leipzig, Germany;
| | - Anne Müglitz
- Rudolf Boehm Institute for Pharmacology and Toxicology, Leipzig University, 04107 Leipzig, Germany; (X.-N.C.); (A.M.); (Y.G.); (M.S.)
| | - Yuanyuan Gong
- Rudolf Boehm Institute for Pharmacology and Toxicology, Leipzig University, 04107 Leipzig, Germany; (X.-N.C.); (A.M.); (Y.G.); (M.S.)
| | - Michael Schaefer
- Rudolf Boehm Institute for Pharmacology and Toxicology, Leipzig University, 04107 Leipzig, Germany; (X.-N.C.); (A.M.); (Y.G.); (M.S.)
| | - Ralf Regenthal
- Clinical Pharmacology, Rudolf Boehm Institute for Pharmacology and Toxicology, Leipzig University, 04107 Leipzig, Germany;
| | - Ute Krügel
- Rudolf Boehm Institute for Pharmacology and Toxicology, Leipzig University, 04107 Leipzig, Germany; (X.-N.C.); (A.M.); (Y.G.); (M.S.)
- Correspondence:
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5
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Abstract
TRPC3 is a Ca2+-permeable cation channel commonly activated by the G-protein coupled receptors (GPCR) and mechanical distortion of the plasma membrane. TRPC3-mediated Ca2+ influx has been implicated in a variety of signaling processes in both excitable and non-excitable cells. Kidneys play a commanding role in maintaining whole-body homeostasis and setting blood pressure. TRPC3 is expressed abundantly in the renal vasculature and in epithelial cells, where it is well positioned to mediate signaling and transport functions in response to GPCR-dependent endocrine stimuli. In addition, TRPC3 could be activated by mechanical forces resulting from dynamic changes in the renal tubule fluid flow and osmolarity. This review critically analyzes the available published evidence of the physiological roles of TRPC3 in different parts of the kidney and describes the pathophysiological ramifications of TRPC3 ablation. We also speculate how this evidence could be further translated into the clinic.
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Affiliation(s)
- Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
| | - Viktor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
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6
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Ciocarlan A. (+)-Larixol and Larixyl Acetate: Syntheses, Phytochemical Studies and Biological Activity Assessments. CHEMISTRY JOURNAL OF MOLDOVA 2021. [DOI: 10.19261/cjm.2021.836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
(+)-Larixol is a well-known labdane-type diterpenoid widely used in organic synthesis. The present review covers the (+)-larixol based chemical transformations, the results of phytochemical analysis of new (+)-larixol containing species, as well as recent data on biological activity of (+)-larixol and practical applications where it is mentioned.
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7
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Su Y, Chen Q, Ju Y, Li W, Li W. Palmitate induces human glomerular mesangial cells fibrosis through CD36-mediated transient receptor potential canonical channel 6/nuclear factor of activated T cell 2 activation. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158793. [PMID: 32800850 DOI: 10.1016/j.bbalip.2020.158793] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/06/2020] [Accepted: 08/09/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Our previous study suggested that palmitate (PA) induces human glomerular mesangial cells (HMCs) fibrosis. However, the mechanism is not fully understood. Recent studies suggested that transient receptor potential canonical channel 6 (TRPC6)/nuclear factor of activated T cell 2 (NFAT2) played an important role in renal fibrosis. Moreover, cluster of differentiation 36 (CD36) regulated the synthesis of TPRC6 agonist diglyceride. In the present study, we investigated whether PA induced HMCs fibrosis via TRPC6/NFAT2 mediated by CD36. METHODS A type 2 diabetic nephropathy (DN) model was established in Sprague Dawley rats, and HMCs were stimulated with PA. Lipid accumulation and free fatty acid (FFA) uptake were measured. The expression levels of TGF-β1, p-Smad2/3, FN, TRPC6, NFAT2 and CD36 were evaluated. The intracellular calcium concentration ([Ca2+]i) was assessed. RESULTS FFA were elevated in type 2 DN rats with kidney fibrosis in addition to NFAT2 and CD36 expression. In vitro, PA induced HMCs fibrosis, [Ca2+]i elevation and NFAT2 activation. SKF96365 or TRPC6-siRNA could attenuate PA-induced HMCs damage. By contrast, the TRPC6 activator showed the opposite effect. Moreover, NFAT2-siRNA also suppressed PA-induced HMCs fibrosis. CD36 knockdown inhibited the PA-induced [Ca2+]i elevation and NFAT2 expression. In addition, long-term treatment with PA decreased TRPC6 expression in HMCs. CONCLUSION The results of this study demonstrated that PA could induce the activation of the [Ca2+]i/NFAT2 signaling pathway through TRPC6, which led to HMCs fibrosis. Although activation of TRPC6 attributed to CD36-mediated lipid deposition, long-term stimulation of PA may lead to negative feedback on the expression of TPRC6.
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Affiliation(s)
- Yong Su
- Department of Pharmacy, The First Affiliated Hospital of Anhui Medical University, Hefei 230032, Anhui, China; Key Laboratory of Anti-Inflammatory and Immunopharmacology, Ministry of Education, Department of Pharmacology, Anhui Medical University, Hefei 230032, Anhui, China
| | - Qingqing Chen
- Key Laboratory of Anti-Inflammatory and Immunopharmacology, Ministry of Education, Department of Pharmacology, Anhui Medical University, Hefei 230032, Anhui, China
| | - Yinghui Ju
- Department of Pharmacy, Hefei Ion Medical Center, Hefei 230032, Anhui, China
| | - Weizu Li
- Key Laboratory of Anti-Inflammatory and Immunopharmacology, Ministry of Education, Department of Pharmacology, Anhui Medical University, Hefei 230032, Anhui, China.
| | - Weiping Li
- Key Laboratory of Anti-Inflammatory and Immunopharmacology, Ministry of Education, Department of Pharmacology, Anhui Medical University, Hefei 230032, Anhui, China; Anqing Medical and Pharmaceutical College, Anqing 246052, Anhui, China.
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8
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Dryer SE, Roshanravan H, Kim EY. TRPC channels: Regulation, dysregulation and contributions to chronic kidney disease. Biochim Biophys Acta Mol Basis Dis 2019; 1865:1041-1066. [PMID: 30953689 DOI: 10.1016/j.bbadis.2019.04.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 12/13/2022]
Abstract
Mutations in the gene encoding canonical transient receptor potential-6 (TRPC6) channels result in severe nephrotic syndromes that typically lead to end-stage renal disease. Many but not all of these mutations result in a gain in the function of the resulting channel protein. Since those observations were first made, substantial work has supported the hypothesis that TRPC6 channels can also contribute to progression of acquired (non-genetic) glomerular diseases, including primary and secondary FSGS, glomerulosclerosis during autoimmune glomerulonephritis, and possibly in type-1 diabetes. Their regulation has been extensively studied, especially in podocytes, but also in mesangial cells and other cell types present in the kidney. More recent evidence has implicated TRPC6 in renal fibrosis and tubulointerstitial disease caused by urinary obstruction. Consequently TRPC6 is being extensively investigated as a target for drug discovery. Other TRPC family members are present in kidney. TRPC6 can form a functional heteromultimer with TRPC3, and it has been suggested that TRPC5 may also play a role in glomerular disease progression, although the evidence on this is contradictory. Here we review literature on the expression and regulation of TRPC6, TRPC3 and TRPC5 in various cell types of the vertebrate kidney, the evidence that these channels are dysregulated in disease models, and research showing that knock-out or pharmacological inhibition of these channels can reduce the severity of kidney disease. We also summarize several areas that remain controversial, and some of the large gaps of knowledge concerning the fundamental role of these proteins in regulation of renal function.
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Affiliation(s)
- Stuart E Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA; Department of Internal Medicine, Division of Nephrology, Baylor College of Medicine, Houston, TX, USA.
| | - Hila Roshanravan
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Eun Young Kim
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
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9
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Correction. Br J Pharmacol 2019; 176:981. [PMID: 30912131 PMCID: PMC6433642 DOI: 10.1111/bph.14629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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10
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Tan YQ, Kwan HY, Yao X, Leung LK. The activity of transient receptor potential channel C‐6 modulates the differentiation of fat cells. FASEB J 2019; 33:6526-6538. [DOI: 10.1096/fj.201801518rr] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yan Qin Tan
- School of Life SciencesFaculty of ScienceBaptist University Hong Kong China
| | - Hiu Yee Kwan
- School of Chinese MedicineBaptist University Hong Kong China
| | - Xiaoqiang Yao
- School of Biomedical SciencesFaculty of MedicineThe Chinese University of Hong Kong Hong Kong China
| | - Lai K. Leung
- School of Life SciencesFaculty of ScienceBaptist University Hong Kong China
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11
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Azumaya CM, Sierra-Valdez F, Cordero-Morales JF, Nakagawa T. Cryo-EM structure of the cytoplasmic domain of murine transient receptor potential cation channel subfamily C member 6 (TRPC6). J Biol Chem 2018; 293:10381-10391. [PMID: 29752403 PMCID: PMC6028952 DOI: 10.1074/jbc.ra118.003183] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/08/2018] [Indexed: 01/08/2023] Open
Abstract
The kidney maintains the internal milieu by regulating the retention and excretion of proteins, ions, and small molecules. The glomerular podocyte forms the slit diaphragm of the ultrafiltration filter, whose damage leads to progressive kidney failure and focal segmental glomerulosclerosis (FSGS). The canonical transient receptor potential 6 (TRPC6) ion channel is expressed in the podocyte, and mutations in its cytoplasmic domain cause FSGS in humans. In vitro evaluation of disease-causing mutations in TRPC6 has revealed that these genetic alterations result in abnormal ion channel gating. However, the mechanism whereby the cytoplasmic domain modulates TRPC6 function is largely unknown. Here, we report a cryo-EM structure of the cytoplasmic domain of murine TRPC6 at 3.8 Å resolution. The cytoplasmic fold of TRPC6 is characterized by an inverted dome-like chamber pierced by four radial horizontal helices that converge into a vertical coiled-coil at the central axis. Unlike other TRP channels, TRPC6 displays a unique domain swap that occurs at the junction of the horizontal helices and coiled-coil. Multiple FSGS mutations converge at the buried interface between the vertical coiled-coil and the ankyrin repeats, which form the dome, suggesting these regions are critical for allosteric gating modulation. This functionally critical interface is a potential target for drug design. Importantly, dysfunction in other family members leads to learning deficits (TRPC1/4/5) and ataxia (TRPC3). Our data provide a structural framework for the mechanistic investigation of the TRPC family.
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Affiliation(s)
| | - Francisco Sierra-Valdez
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Julio F Cordero-Morales
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Terunaga Nakagawa
- From the Department of Molecular Physiology and Biophysics,
- Center for Structural Biology, and
- Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
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12
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Häfner S, Burg F, Kannler M, Urban N, Mayer P, Dietrich A, Trauner D, Broichhagen J, Schaefer M. A (+)-Larixol Congener with High Affinity and Subtype Selectivity toward TRPC6. ChemMedChem 2018. [PMID: 29522264 DOI: 10.1002/cmdc.201800021] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Natural products have many health benefits, and their application can improve the quality of life. Recently, the diterpene (+)-larixol and its acetylated congeners demonstrated selective inhibition of the second-messenger-gated cation channel transient receptor potential canonical 6 (TRPC6) over its close isoforms TRPC3 and TRPC7. Building on this knowledge, we expanded these findings by chemical diversification of (+)-larixol mostly at position C6. Implementing high-throughput Ca2+ FLIPR screening assays and electrophysiological patch-clamp recordings, we showcase larixyl N-methylcarbamate, termed SH045, as a compound with nanomolar affinity and 13-fold subtype selectivity over TRPC3 in stably expressing HEK293 cells. Expanding on this finding, TRPC6 inhibition was also observed in rat pulmonary smooth muscle cells. Furthermore, treatment of isolated perfused lung preparations with SH045 led to a decrease in lung ischemia-reperfusion edema (LIRE), a life-threatening condition associated with TRPC6 that may occur after organ transplantation. Taken together, and given the inexpensive, straightforward, and scalable preparation of SH045, we report a TRPC6 blocker that holds promise for the translational treatment of LIRE.
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Affiliation(s)
- Stephanie Häfner
- Rudolf Boehm Institute for Pharmacology and Toxicology, Leipzig University, Härtelstr. 16-18, 04107, Leipzig, Germany
| | - Finn Burg
- Department of Chemistry, Ludwig Maximilians University Munich and Center for Integrated Protein Science Munich, Butenandtstr. 5-13, 81377, Munich, Germany
| | - Martina Kannler
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig Maximilians University Munich, Nußbaumstr. 26, 80336, Munich, Germany
| | - Nicole Urban
- Rudolf Boehm Institute for Pharmacology and Toxicology, Leipzig University, Härtelstr. 16-18, 04107, Leipzig, Germany
| | - Peter Mayer
- Department of Chemistry, Ludwig Maximilians University Munich and Center for Integrated Protein Science Munich, Butenandtstr. 5-13, 81377, Munich, Germany
| | - Alexander Dietrich
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig Maximilians University Munich, Nußbaumstr. 26, 80336, Munich, Germany
| | - Dirk Trauner
- Department of Chemistry, Ludwig Maximilians University Munich and Center for Integrated Protein Science Munich, Butenandtstr. 5-13, 81377, Munich, Germany.,Present address: Department of Chemistry, Silver Center for Arts and Science, New York University, 100 Washington Square East, New York, NY, 10003, USA
| | - Johannes Broichhagen
- Department of Chemistry, Ludwig Maximilians University Munich and Center for Integrated Protein Science Munich, Butenandtstr. 5-13, 81377, Munich, Germany.,Present address: Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstr. 29, 69120, Heidelberg, Germany
| | - Michael Schaefer
- Rudolf Boehm Institute for Pharmacology and Toxicology, Leipzig University, Härtelstr. 16-18, 04107, Leipzig, Germany
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13
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Urban N, Neuser S, Hentschel A, Köhling S, Rademann J, Schaefer M. Pharmacological inhibition of focal segmental glomerulosclerosis-related, gain of function mutants of TRPC6 channels by semi-synthetic derivatives of larixol. Br J Pharmacol 2017; 174:4099-4122. [PMID: 28800680 DOI: 10.1111/bph.13977] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 07/24/2017] [Accepted: 07/31/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE Gain of function mutations in TRPC6 channels can cause autosomal dominant forms of focal segmental glomerulosclerosis (FSGS). Validated inhibitors of TRPC6 channels that are biologically active on FSGS-related TRPC6 mutants are eagerly sought. EXPERIMENTAL APPROACH We synthesized new TRPC6-inhibiting modulators from larixol, a resiniferous constituent of Larix decidua, and tested the potency and selectivity in cell lines stably expressing various TRPC channel isoforms. Channel activation was followed by Ca2+ influx analyses and electrophysiological recordings. The most promising compound larixyl carbamate (LC) was tested on native TRPC6 channels and TRPC6 constructs carrying FSGS-related point mutations. KEY RESULTS LC exhibited an about 30-fold preference for TRPC6 over TRPC3 channels and a fivefold preference for TRPC6 over TRPC7 channels. Six FSGS-related TRPC6 mutants, including the highly active M132T and R175Q variants, were strongly inhibited by 1 μM LC. Surprisingly, no TRPC6-related Ca2+ signals were detectable in primary murine podocytes, or in acutely isolated glomeruli. in these preparations. Quantitative PCR revealed a 20-fold to 50-fold lower abundance of TRPC6 transcripts in rat or mouse podocytes, compared with pulmonary artery smooth muscle cells from the same species. Accordingly, electrophysiological recordings demonstrated that DAG-induced currents in murine podocytes are very small, but sensitive to LC. CONCLUSIONS AND IMPLICATIONS In spite of their low abundance in native podocytes, native TRPC6 channels are targetable using larixol-derived TRPC6 inhibitors. As observed with wild-type TRPC6 channels, FSGS-related TRPC6 mutants were sensitive to the newly developed inhibitors, paving the way for experimental therapies.
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Affiliation(s)
- Nicole Urban
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
| | - Sonja Neuser
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
| | - Anika Hentschel
- Institut für Pharmazie, Freie Universität Berlin, Berlin, Germany
| | | | - Jörg Rademann
- Institut für Pharmazie, Freie Universität Berlin, Berlin, Germany
| | - Michael Schaefer
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
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