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Chi G, Jaślan D, Kudrina V, Böck J, Li H, Pike ACW, Rautenberg S, Krogsaeter E, Bohstedt T, Wang D, McKinley G, Fernandez-Cid A, Mukhopadhyay SMM, Burgess-Brown NA, Keller M, Bracher F, Grimm C, Dürr KL. Structural basis for inhibition of the lysosomal two-pore channel TPC2 by a small molecule antagonist. Structure 2024; 32:1137-1149.e4. [PMID: 38815576 DOI: 10.1016/j.str.2024.05.005] [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: 05/18/2023] [Revised: 10/22/2023] [Accepted: 05/03/2024] [Indexed: 06/01/2024]
Abstract
Two pore channels are lysosomal cation channels with crucial roles in tumor angiogenesis and viral release from endosomes. Inhibition of the two-pore channel 2 (TPC2) has emerged as potential therapeutic strategy for the treatment of cancers and viral infections, including Ebola and COVID-19. Here, we demonstrate that antagonist SG-094, a synthetic analog of the Chinese alkaloid medicine tetrandrine with increased potency and reduced toxicity, induces asymmetrical structural changes leading to a single binding pocket at only one intersubunit interface within the asymmetrical dimer. Supported by functional characterization of mutants by Ca2+ imaging and patch clamp experiments, we identify key residues in S1 and S4 involved in compound binding to the voltage sensing domain II. SG-094 arrests IIS4 in a downward shifted state which prevents pore opening via the IIS4/S5 linker, hence resembling gating modifiers of canonical VGICs. These findings may guide the rational development of new therapeutics antagonizing TPC2 activity.
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Affiliation(s)
- Gamma Chi
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK.
| | - Dawid Jaślan
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Ludwig-Maximilians-Universität, Nussbaumstrasse 26, 80336 Munich, Germany
| | - Veronika Kudrina
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Ludwig-Maximilians-Universität, Nussbaumstrasse 26, 80336 Munich, Germany
| | - Julia Böck
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Ludwig-Maximilians-Universität, Nussbaumstrasse 26, 80336 Munich, Germany
| | - Huanyu Li
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK
| | - Ashley C W Pike
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK
| | - Susanne Rautenberg
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Butenandtstrasse 7, 81377 Munich, Germany
| | - Einar Krogsaeter
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Ludwig-Maximilians-Universität, Nussbaumstrasse 26, 80336 Munich, Germany
| | - Tina Bohstedt
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK
| | - Dong Wang
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK
| | - Gavin McKinley
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK
| | - Alejandra Fernandez-Cid
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK
| | - Shubhashish M M Mukhopadhyay
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK
| | - Nicola A Burgess-Brown
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK
| | - Marco Keller
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Butenandtstrasse 7, 81377 Munich, Germany
| | - Franz Bracher
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Butenandtstrasse 7, 81377 Munich, Germany
| | - Christian Grimm
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Ludwig-Maximilians-Universität, Nussbaumstrasse 26, 80336 Munich, Germany; Immunology, Infection and Pandemic Research IIP, Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Munich/Frankfurt, Germany
| | - Katharina L Dürr
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Nuffield Department of Medicine Research Building, Oxford OX3 7FZ, UK
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2
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Zhou D, Eraslan Z, Miller D, Taylor I, You J, Grondin SJ, Vega M, Manga P, Goff PS, Sviderskaya EV, Gross SS, Chen Q, Zippin JH. Two-pore channel 2 is required for soluble adenylyl cyclase-dependent regulation of melanosomal pH and melanin synthesis. Pigment Cell Melanoma Res 2024. [PMID: 38844435 DOI: 10.1111/pcmr.13177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 04/25/2024] [Accepted: 05/24/2024] [Indexed: 07/17/2024]
Abstract
Melanosomal pH is important for the synthesis of melanin as the rate-limiting enzyme, tyrosinase, is very pH-sensitive. The soluble adenylyl cyclase (sAC) signaling pathway was recently identified as a regulator of melanosomal pH in melanocytes; however, the melanosomal proteins critical for sAC-dependent regulation of melanosomal pH were undefined. We now systematically examine four well-characterized melanosomal membrane proteins to determine whether any of them are required for sAC-dependent regulation of melanosomal pH. We find that OA1, OCA2, and SLC45A2 are dispensable for sAC-dependent regulation of melanosomal pH. In contrast, TPC2 activity is required for sAC-dependent regulation of melanosomal pH and melanin synthesis. In addition, activation of TPC2 by NAADP-AM rescues melanosomal pH alkalinization and reduces melanin synthesis following pharmacologic or genetic inhibition of sAC signaling. These studies establish TPC2 as a critical melanosomal protein for sAC-dependent regulation of melanosomal pH and pigmentation.
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Affiliation(s)
- Dalee Zhou
- Department of Dermatology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Zuhal Eraslan
- Department of Dermatology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Dawson Miller
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Isobel Taylor
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Jaewon You
- Department of Dermatology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Samuel J Grondin
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Martha Vega
- The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York, USA
| | - Prashiela Manga
- The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York, USA
| | - Philip S Goff
- Cell Biology Research Section, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Elena V Sviderskaya
- Cell Biology Research Section, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Steven S Gross
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Qiuying Chen
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Jonathan H Zippin
- Department of Dermatology, Weill Cornell Medical College of Cornell University, New York, New York, USA
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
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3
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Ouologuem L, Bartel K. Endolysosomal transient receptor potential mucolipins and two-pore channels: implications for cancer immunity. Front Immunol 2024; 15:1389194. [PMID: 38840905 PMCID: PMC11150529 DOI: 10.3389/fimmu.2024.1389194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/09/2024] [Indexed: 06/07/2024] Open
Abstract
Past research has identified that cancer cells sustain several cancer hallmarks by impairing function of the endolysosomal system (ES). Thus, maintaining the functional integrity of endolysosomes is crucial, which heavily relies on two key protein families: soluble hydrolases and endolysosomal membrane proteins. Particularly members of the TPC (two-pore channel) and TRPML (transient receptor potential mucolipins) families have emerged as essential regulators of ES function as a potential target in cancer therapy. Targeting TPCs and TRPMLs has demonstrated significant impact on multiple cancer hallmarks, including proliferation, growth, migration, and angiogenesis both in vitro and in vivo. Notably, endosomes and lysosomes also actively participate in various immune regulatory mechanisms, such as phagocytosis, antigen presentation, and the release of proinflammatory mediators. Yet, knowledge about the role of TPCs and TRPMLs in immunity is scarce. This prompts a discussion regarding the potential role of endolysosomal ion channels in aiding cancers to evade immune surveillance and destruction. Specifically, understanding the interplay between endolysosomal ion channels and cancer immunity becomes crucial. Our review aims to comprehensively explore the current knowledge surrounding the roles of TPCs and TRPMLs in immunity, whilst emphasizing the critical need to elucidate their specific contributions to cancer immunity by pointing out current research gaps that should be addressed.
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Affiliation(s)
| | - Karin Bartel
- Department of Pharmacy, Drug Delivery, Ludwig-Maximilians-University Munich, Munich, Germany
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4
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Hanbashi A, Alotaibi M, Sobeai HMA, Binobaid L, Alhazzani K, Jin X, Kamli F, Alhoshani A, Parrington J. Loss of two-pore channel 2 function in melanoma-derived tumours reduces tumour growth in vivo but greatly increases tumour-related toxicity in the organism. Cancer Cell Int 2023; 23:325. [PMID: 38104117 PMCID: PMC10725603 DOI: 10.1186/s12935-023-03148-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 11/14/2023] [Indexed: 12/19/2023] Open
Abstract
BACKGROUND Melanoma, a severe form of skin cancer, poses significant health risks due to its aggressive nature and potential for metastasis. The role of two-pore channel 2 (TPC2) in the development and progression of melanoma remains poorly understood. This study aims to investigate the impact of TPC2 knockout (KO) on melanoma-derived tumors, focusing on tumour growth and related toxicity in the organism. METHODS The study utilized CHL-1 and B16 melanoma cell lines with TPC2 KO to assess the changes in proliferation dynamics. Methods included real-time monitoring of cell proliferation using the xCELLigence system, in vivo tumour growth assays in mice, histopathological analyses, inflammation marker assessment, and quantitative PCR (qPCR) for gene expression analysis RESULTS: TPC2 KO was found to significantly alter the proliferation dynamics of CHL-1 and B16 melanoma cells. The in vivo studies demonstrated reduced tumor growth in TPC2 KO cell-derived tumors. However, a notable increase in tumor-related toxicity in affected organs, such as the liver and spleen, was observed, indicating a complex role of TPC2 in melanoma pathology. CONCLUSIONS The loss of TPC2 function in melanoma cells leads to reduced tumour growth but exacerbates tumour-related toxicity in the organism. These findings highlight the dual role of TPC2 in melanoma progression and its potential as a therapeutic target. Further research is needed to fully understand the mechanisms underlying these effects and to explore TPC2 as a treatment target in melanoma.
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Affiliation(s)
- Ali Hanbashi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Moureq Alotaibi
- Dept. of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Kingdom of Saudi Arabia, P.O. Box 2457, Riyadh, 11454, Saudi Arabia
| | - Homood M As Sobeai
- Dept. of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Kingdom of Saudi Arabia, P.O. Box 2457, Riyadh, 11454, Saudi Arabia
| | - Lama Binobaid
- Dept. of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Kingdom of Saudi Arabia, P.O. Box 2457, Riyadh, 11454, Saudi Arabia
| | - Khalid Alhazzani
- Dept. of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Kingdom of Saudi Arabia, P.O. Box 2457, Riyadh, 11454, Saudi Arabia
| | - Xuhui Jin
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Faroq Kamli
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Ali Alhoshani
- Dept. of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Kingdom of Saudi Arabia, P.O. Box 2457, Riyadh, 11454, Saudi Arabia
| | - John Parrington
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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5
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Davis LC, Morgan AJ, Galione A. Optical profiling of autonomous Ca 2+ nanodomains generated by lysosomal TPC2 and TRPML1. Cell Calcium 2023; 116:102801. [PMID: 37742482 DOI: 10.1016/j.ceca.2023.102801] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/30/2023] [Accepted: 09/17/2023] [Indexed: 09/26/2023]
Abstract
Multiple families of Ca2+-permeable channels co-exist on lysosomal Ca2+ stores but how each family couples to its own unique downstream physiology is unclear. We have therefore investigated the Ca2+-signalling architecture underpinning different channels on the same vesicle that drive separate pathways, using phagocytosis as a physiological stimulus. Lysosomal Ca2+-channels are a major Ca2+ source driving particle uptake in macrophages, but different channels drive different aspects of Fc-receptor-mediated phagocytosis: TPC2 couples to dynamin activation, whilst TRPML1 couples to lysosomal exocytosis. We hypothesised that they are driven by discrete local plumes of Ca2+ around open channels (Ca2+ nanodomains). To test this, we optimized Ca2+-nanodomain recordings by screening panels of genetically encoded Ca2+ indicators (GECIs) fused to TPC2 to monitor the [Ca2+] next to the channel. Signal calibration accounting for the distance of the GECI from the channel mouth reveals that, during phagocytosis, TPC2 generates local Ca2+ nanodomains around itself of up to 42 µM, nearly a hundred-fold greater than the global cytosolic [Ca2+] rise. We further show that TPC2 and TRPML1, though on the same lysosomes, generate autonomous Ca2+ nanodomains of high [Ca2+] that are largely insulated from one another, a platform allowing their discrete Ca2+-decoding to promote unique respective physiologies.
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Affiliation(s)
- Lianne C Davis
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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6
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Chen CC. Electrophysiological Techniques on the Study of Endolysosomal Ion Channels. Handb Exp Pharmacol 2023; 278:217-233. [PMID: 36871125 DOI: 10.1007/164_2023_638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Endolysosomal ion channels are a group of ion channel proteins that are functionally expressed on the membrane of endolysosomal vesicles. The electrophysiological properties of these ion channels in the intracellular organelle membrane cannot be observed using conventional electrophysiological techniques. This section compiles the different electrophysiological techniques utilized in recent years to study endolysosomal ion channels and describes their methodological characteristics, emphasizing the most widely used technique for whole endolysosome recordings to date. This includes the use of different pharmacological tools and genetic tools for the application of patch-clamping techniques for specific stages of endolysosomes, allowing the recording of ion channel activity in different organelles, such as recycling endosomes, early endosomes, late endosomes, and lysosomes. These electrophysiological techniques are not only cutting-edge technologies that help to investigate the biophysical properties of known and unknown intracellular ion channels but also help us to investigate the physiopathological role of these ion channels in the distribution of dynamic vesicles and to identify new therapeutic targets for precision medicine and drug screening.
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Affiliation(s)
- Cheng-Chang Chen
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan.
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan.
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7
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Murenu E, Gerhardt MJ, Biel M, Michalakis S. More than meets the eye: The role of microglia in healthy and diseased retina. Front Immunol 2022; 13:1006897. [PMID: 36524119 PMCID: PMC9745050 DOI: 10.3389/fimmu.2022.1006897] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/11/2022] [Indexed: 11/30/2022] Open
Abstract
Microglia are the main resident immune cells of the nervous system and as such they are involved in multiple roles ranging from tissue homeostasis to response to insults and circuit refinement. While most knowledge about microglia comes from brain studies, some mechanisms have been confirmed for microglia cells in the retina, the light-sensing compartment of the eye responsible for initial processing of visual information. However, several key pieces of this puzzle are still unaccounted for, as the characterization of retinal microglia has long been hindered by the reduced population size within the retina as well as the previous lack of technologies enabling single-cell analyses. Accumulating evidence indicates that the same cell type may harbor a high degree of transcriptional, morphological and functional differences depending on its location within the central nervous system. Thus, studying the roles and signatures adopted specifically by microglia in the retina has become increasingly important. Here, we review the current understanding of retinal microglia cells in physiology and in disease, with particular emphasis on newly discovered mechanisms and future research directions.
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Affiliation(s)
- Elisa Murenu
- Department of Ophthalmology, Klinikum der Ludwig-Maximilians-Universität München, Munich, Germany,*Correspondence: Elisa Murenu, ; ; Stylianos Michalakis,
| | | | - Martin Biel
- Department of Pharmacy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Stylianos Michalakis
- Department of Ophthalmology, Klinikum der Ludwig-Maximilians-Universität München, Munich, Germany,*Correspondence: Elisa Murenu, ; ; Stylianos Michalakis,
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8
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Blood Transcriptome Analysis of Beef Cow with Different Parity Revealed Candidate Genes and Gene Networks Regulating the Postpartum Diseases. Genes (Basel) 2022; 13:genes13091671. [PMID: 36140838 PMCID: PMC9498831 DOI: 10.3390/genes13091671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/05/2022] [Accepted: 09/15/2022] [Indexed: 11/16/2022] Open
Abstract
Maternal parity is an important physiological factor influencing beef cow reproductive performance. However, there are few studies on the influence of different calving periods on early growth and postpartum diseases. Here, we conducted blood transcriptomic analysis on cows of different parities for gene discovery. We used Short Time Series Expression Miner (STEM) analysis to determine gene expression levels in cows of various parities and divided multiple parities into three main periods (nulliparous, primiparous, and multiparous) for subsequent analysis. Furthermore, the top 15,000 genes with the lowest median absolute deviation (MAD) were used to build a co-expression network using weighted correlation network analysis (WGCNA), and six independent modules were identified. Combing with Exon Wide Selection Signature (EWSS) and protein-protein interaction (PPI) analysis revealed that TPCN2, KIF22, MICAL3, RUNX2, PDE4A, TESK2, GPM6A, POLR1A, and KLHL6 involved in early growth and postpartum diseases. The GO and KEGG enrichment showed that the Parathyroid hormone synthesis, secretion, and action pathway and stem cell differentiation function-related pathways were enriched. Collectively, our study revealed candidate genes and gene networks regulating the early growth and postpartum diseases and provided new insights into the potential mechanism of reproduction advantages of different parity selection.
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9
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Two-pore channels: going with the flows. Biochem Soc Trans 2022; 50:1143-1155. [PMID: 35959977 PMCID: PMC9444070 DOI: 10.1042/bst20220229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 11/26/2022]
Abstract
In recent years, our understanding of the structure, mechanisms and functions of the endo-lysosomal TPC (two-pore channel) family have grown apace. Gated by the second messengers, NAADP and PI(3,5)P2, TPCs are an integral part of fundamental signal-transduction pathways, but their array and plasticity of cation conductances (Na+, Ca2+, H+) allow them to variously signal electrically, osmotically or chemically. Their relative tissue- and organelle-selective distribution, together with agonist-selective ion permeabilities provides a rich palette from which extracellular stimuli can choose. TPCs are emerging as mediators of immunity, cancer, metabolism, viral infectivity and neurodegeneration as this short review attests.
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10
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Patel S, Yuan Y, Chen CC, Jaślan D, Gunaratne G, Grimm C, Rahman T, Marchant JS. Electrophysiology of Endolysosomal Two-Pore Channels: A Current Account. Cells 2022; 11:2368. [PMID: 35954212 PMCID: PMC9368155 DOI: 10.3390/cells11152368] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 12/10/2022] Open
Abstract
Two-pore channels TPC1 and TPC2 are ubiquitously expressed pathophysiologically relevant proteins that reside on endolysosomal vesicles. Here, we review the electrophysiology of these channels. Direct macroscopic recordings of recombinant TPCs expressed in enlarged lysosomes in mammalian cells or vacuoles in plants and yeast demonstrate gating by the Ca2+-mobilizing messenger NAADP and/or the lipid PI(3,5)P2. TPC currents are regulated by H+, Ca2+, and Mg2+ (luminal and/or cytosolic), as well as protein kinases, and they are impacted by single-nucleotide polymorphisms linked to pigmentation. Bisbenzylisoquinoline alkaloids, flavonoids, and several approved drugs demonstrably block channel activity. Endogenous TPC currents have been recorded from a number of primary cell types and cell lines. Many of the properties of endolysosomal TPCs are recapitulated upon rerouting channels to the cell surface, allowing more facile recording through conventional electrophysiological means. Single-channel analyses have provided high-resolution insight into both monovalent and divalent permeability. The discovery of small-molecule activators of TPC2 that toggle the ion selectivity from a Ca2+-permeable (NAADP-like) state to a Na+-selective (PI(3,5)P2-like) state explains discrepancies in the literature relating to the permeability of TPCs. Identification of binding proteins that confer NAADP-sensitive currents confirm that indirect, remote gating likely underpins the inconsistent observations of channel activation by NAADP.
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Affiliation(s)
- Sandip Patel
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK;
| | - Yu Yuan
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK;
| | - Cheng-Chang Chen
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei 100229, Taiwan;
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei 100225, Taiwan
| | - Dawid Jaślan
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians University, 80336 Munich, Germany; (D.J.); (C.G.)
| | - Gihan Gunaratne
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA; (G.G.); (J.S.M.)
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians University, 80336 Munich, Germany; (D.J.); (C.G.)
| | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, UK;
| | - Jonathan S. Marchant
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA; (G.G.); (J.S.M.)
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11
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Chen CC, Krogsaeter E, Kuo CY, Huang MC, Chang SY, Biel M. Endolysosomal cation channels point the way towards precision medicine of cancer and infectious diseases. Biomed Pharmacother 2022; 148:112751. [PMID: 35240524 DOI: 10.1016/j.biopha.2022.112751] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 11/02/2022] Open
Abstract
Infectious diseases and cancer are among the key medical challenges that humankind is facing today. A growing amount of evidence suggests that ion channels in the endolysosomal system play a crucial role in the pathology of both groups of diseases. The development of advanced patch-clamp technologies has allowed us to directly characterize ion fluxes through endolysosomal ion channels in their native environments. Endolysosomes are essential organelles for intracellular transport, digestion and metabolism, and maintenance of homeostasis. The endolysosomal ion channels regulate the function of the endolysosomal system through four basic mechanisms: calcium release, control of membrane potential, pH change, and osmolarity regulation. In this review, we put particular emphasis on the endolysosomal cation channels, including TPC2 and TRPML2, which are particularly important in monocyte function. We discuss existing endogenous and synthetic ligands of these channels and summarize current knowledge of their impact on channel activity and function in different cell types. Moreover, we summarize recent findings on the importance of TPC2 and TRPML2 channels as potential drug targets for the prevention and treatment of the emerging infectious diseases and cancer.
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Affiliation(s)
- Cheng-Chang Chen
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan.
| | | | - Ching-Ying Kuo
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Min-Chuan Huang
- Graduate Institute of Anatomy and Cell Biology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Sui-Yuan Chang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Martin Biel
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
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Skelding KA, Barry DL, Theron DZ, Lincz LF. Targeting the two-pore channel 2 in cancer progression and metastasis. EXPLORATION OF TARGETED ANTI-TUMOR THERAPY 2022; 3:62-89. [PMID: 36046356 PMCID: PMC9400767 DOI: 10.37349/etat.2022.00072] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/02/2022] [Indexed: 11/19/2022] Open
Abstract
The importance of Ca2+ signaling, and particularly Ca2+ channels, in key events of cancer cell function such as proliferation, metastasis, autophagy and angiogenesis, has recently begun to be appreciated. Of particular note are two-pore channels (TPCs), a group of recently identified Ca2+-channels, located within the endolysosomal system. TPC2 has recently emerged as an intracellular ion channel of significant pathophysiological relevance, specifically in cancer, and interest in its role as an anti-cancer drug target has begun to be explored. Herein, an overview of the cancer-related functions of TPC2 and a discussion of its potential as a target for therapeutic intervention, including a summary of clinical trials examining the TPC2 inhibitors, naringenin, tetrandrine, and verapamil for the treatment of various cancers is provided.
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Affiliation(s)
- Kathryn A. Skelding
- Cancer Cell Biology Research Group, School of Biomedical Sciences and Pharmacy, College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, New South Wales 2308, Australia;Hunter Medical Research Institute, New Lambton Heights, New South Wales 2305, Australia
| | - Daniel L. Barry
- Cancer Cell Biology Research Group, School of Biomedical Sciences and Pharmacy, College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, New South Wales 2308, Australia;Hunter Medical Research Institute, New Lambton Heights, New South Wales 2305, Australia
| | - Danielle Z. Theron
- Cancer Cell Biology Research Group, School of Biomedical Sciences and Pharmacy, College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, New South Wales 2308, Australia;Hunter Medical Research Institute, New Lambton Heights, New South Wales 2305, Australia
| | - Lisa F. Lincz
- Cancer Cell Biology Research Group, School of Biomedical Sciences and Pharmacy, College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, New South Wales 2308, Australia;Hunter Medical Research Institute, New Lambton Heights, New South Wales 2305, Australia;Hunter Hematology Research Group, Calvary Mater Newcastle Hospital, Waratah, New South Wales 2298, Australia
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