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Capellmann S, Kauffmann M, Arock M, Huber M. SR-BI regulates the synergistic mast cell response by modulating the plasma membrane-associated cholesterol pool. Eur J Immunol 2024:e2350788. [PMID: 38708681 DOI: 10.1002/eji.202350788] [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: 09/26/2023] [Revised: 04/24/2024] [Accepted: 04/26/2024] [Indexed: 05/07/2024]
Abstract
The high-affinity IgE receptor FcεRI is the mast cell (MC) receptor responsible for the involvement of MCs in IgE-associated allergic disorders. Activation of the FcεRI is achieved via crosslinking by multivalent antigen (Ag) recognized by IgE resulting in degranulation and proinflammatory cytokine production. In comparison to the T- and B-cell receptor complexes, for which several co-receptors orchestrating the initial signaling events have been described, information is scarce about FcεRI-associated proteins. Additionally, it is unclear how FcεRI signaling synergizes with input from other receptors and how regulators affect this synergistic response. We found that the HDL receptor SR-BI (gene name: Scarb1/SCARB1) is expressed in MCs, functionally associates with FcεRI, and regulates the plasma membrane cholesterol content in cholesterol-rich plasma membrane nanodomains. This impacted the activation of MCs upon co-stimulation of the FcεRI with receptors known to synergize with FcεRI signaling. Amongst them, we investigated the co-activation of the FcεRI with the receptor tyrosine kinase KIT, the IL-33 receptor, and GPCRs activated by adenosine or PGE2. Scarb1-deficient bone marrow-derived MCs showed reduced cytokine secretion upon co-stimulation conditions suggesting a role for plasma membrane-associated cholesterol regulating respective MC activation. Mimicking Scarb1 deficiency by cholesterol depletion employing MβCD, we identified PKB and PLCγ1 as cholesterol-sensitive proteins downstream of FcεRI activation in bone marrow-derived MCs. When MCs were co-stimulated with stem cell factor (SCF) and Ag, PLCγ1 activation was boosted, which could be mitigated by cholesterol depletion and SR-BI inhibition. Similarly, SR-BI inhibition attenuated the synergistic response to PGE2 and anti-IgE in the human ROSAKIT WT MC line, suggesting that SR-BI is a crucial regulator of synergistic MC activation.
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Affiliation(s)
- Sandro Capellmann
- Institute of Biochemistry and Molecular Immunology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Marlies Kauffmann
- Institute of Biochemistry and Molecular Immunology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Michel Arock
- Department of Hematological Biology, Pitié-Salpêtrière Charles-Foix Hospital, AP-HP Sorbonne University, Paris, France
| | - Michael Huber
- Institute of Biochemistry and Molecular Immunology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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2
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Ma M, Zheng Y, Lu S, Pan X, Worley KC, Burrage LC, Blieden LS, Allworth A, Chen WL, Merla G, Mandriani B, Rosenfeld JA, Li-Kroeger D, Dutta D, Yamamoto S, Wangler MF, Glass IA, Strohbehn S, Blue E, Prontera P, Lalani SR, Bellen HJ. De novo variants in PLCG1 are associated with hearing impairment, ocular pathology, and cardiac defects. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.08.23300523. [PMID: 38260438 PMCID: PMC10802640 DOI: 10.1101/2024.01.08.23300523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Phospholipase C isozymes (PLCs) hydrolyze phosphatidylinositol 4,5-bisphosphate into inositol 1,4,5-trisphosphate and diacylglycerol, important signaling molecules involved in many cellular processes. PLCG1 encodes the PLCγ1 isozyme that is broadly expressed. Hyperactive somatic mutations of PLCG1 are observed in multiple cancers, but only one germline variant has been reported. Here we describe three unrelated individuals with de novo heterozygous missense variants in PLCG1 (p.Asp1019Gly, p.His380Arg, and p.Asp1165Gly) who exhibit variable phenotypes including hearing loss, ocular pathology and cardiac septal defects. To model these variants in vivo, we generated the analogous variants in the Drosophila ortholog, small wing (sl). We created a null allele slT2A and assessed the expression pattern. sl is broadly expressed, including in wing discs, eye discs, and a subset of neurons and glia. Loss of sl causes wing size reductions, ectopic wing veins and supernumerary photoreceptors. We document that mutant flies exhibit a reduced lifespan and age-dependent locomotor defects. Expressing wild-type sl in slT2A mutant rescues the loss-of-function phenotypes whereas expressing the variants causes lethality. Ubiquitous overexpression of the variants also reduces viability, suggesting that the variants are toxic. Ectopic expression of an established hyperactive PLCG1 variant (p.Asp1165His) in the wing pouch causes severe wing phenotypes, resembling those observed with overexpression of the p.Asp1019Gly or p.Asp1165Gly variants, further arguing that these two are gain-of-function variants. However, the wing phenotypes associated with p.His380Arg overexpression are mild. Our data suggest that the PLCG1 de novo heterozygous missense variants are pathogenic and contribute to the features observed in the probands.
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Affiliation(s)
- Mengqi Ma
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030, USA
| | - Yiming Zheng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030, USA
- Current affiliation: State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, China
| | - Shenzhao Lu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030, USA
| | - Xueyang Pan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030, USA
| | - Kim C. Worley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lindsay C. Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lauren S. Blieden
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Aimee Allworth
- Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Wei-Liang Chen
- Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
- Current affiliation: Children’s National Medical Center and George Washington University, Washington DC 20010, USA
| | - Giuseppe Merla
- Laboratory of Regulatory & Functional Genomics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia 71013, Italy
- Department of Molecular Medicine & Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy
| | - Barbara Mandriani
- Department of Interdisciplinary Medicine, University of Bari “Aldo Moro”, Bari 70121, Italy
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - David Li-Kroeger
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Debdeep Dutta
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030, USA
| | - Michael F. Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030, USA
| | | | - Ian A. Glass
- Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
- Division of Genetic Medicine, Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98195, USA
- Brotman Baty Institute, Seattle, WA 98195, USA
| | - Sam Strohbehn
- Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Elizabeth Blue
- Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
- Brotman Baty Institute, Seattle, WA 98195, USA
- Institute for Public Health Genetics, University of Washington, Seattle, WA 98195, USA
| | - Paolo Prontera
- Medical Genetics Unit, Hospital of Perugia, Perugia 06129, Italy
| | - Seema R. Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J. Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030, USA
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Mackrill JJ. Non-inositol 1,4,5-trisphosphate (IP3) receptor IP3-binding proteins. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - MOLECULAR CELL RESEARCH 2023; 1870:119470. [PMID: 37011730 DOI: 10.1016/j.bbamcr.2023.119470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/23/2023] [Accepted: 03/23/2023] [Indexed: 04/03/2023]
Abstract
Conventionally, myo-D-inositol 1, 4,5-trisphosphate (IP3) is thought to exert its second messenger effects through the gating of IP3R Ca2+ release channels, located in Ca2+-storage organelles like the endoplasmic reticulum. However, there is considerable indirect evidence to support the concept that IP3 might interact with other, non-IP3R proteins within cells. To explore this possibility further, the Protein Data Bank was searched using the term "IP3". This resulted in the retrieval of 203 protein structures, the majority of which were members of the IP3R/ryanodine receptor superfamily of channels. Only 49 of these structures were complexed with IP3. These were inspected for their ability to interact with the carbon-1 phosphate of IP3, since this is the least accessible phosphate group of its precursor, phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). This reduced the number of structures retrieved to 35, of which 9 were IP3Rs. The remaining 26 structures represent a diverse range of proteins, including inositol-lipid metabolizing enzymes, signal transducers, PH domain containing proteins, cytoskeletal anchor proteins, the TRPV4 ion channel, a retroviral Gag protein and fibroblast growth factor 2. Such proteins may impact on IP3 signalling and its effects on cell-biology. This represents an area open for exploration in the field of IP3 signalling.
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Affiliation(s)
- John James Mackrill
- Department of Physiology, University College Cork, Western Gateway Building, Western Road, Cork T12 XF62, Ireland.
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Visvanathan R, Utsuki T, Beck DE, Lendy E, Sun KL, Liu Y, Hering KW, Mesecar A, Zhang ZY, Putt KS. A novel fluorogenic reporter substrate for 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase gamma-2 (PLCγ2): Application to high-throughput screening for activators to treat Alzheimer's disease. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2023:S2472-5552(23)00024-2. [PMID: 36933698 DOI: 10.1016/j.slasd.2023.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/17/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023]
Abstract
A rare coding variant in PLCγ2 (P522R) expressed in microglia induces a mild activation of enzymatic activity when compared to wild-type. This mutation is reported to be protective against the cognitive decline associated with late-onset Alzheimer's disease (LOAD) and therefore, activation of wild-type PLCγ2 has been suggested as a potential therapeutic target for the prevention and treatment of LOAD. Additionally, PLCγ2 has been associated with other diseases such as cancer and some autoimmune disorders where mutations with much greater increases in PLCγ2 activity have been identified. Here, pharmacological inhibition may provide a therapeutic effect. In order to facilitate our investigation of the activity of PLCγ2, we developed an optimized fluorogenic substrate to monitor enzymatic activity in aqueous solution. This was accomplished by first exploring the spectral properties of various "turn-on" fluorophores. The most promising turn-on fluorophore was incorporated into a water-soluble PLCγ2 reporter substrate, which we named C8CF3-coumarin. The ability of PLCγ2 to enzymatically process C8CF3-coumarin was confirmed, and the kinetics of the reaction were determined. Reaction conditions were optimized to identify small molecule activators, and a pilot screen of the Library of Pharmacologically Active Compounds 1280 (LOPAC1280) was performed with the goal of identifying small molecule activators of PLCγ2. The optimized screening conditions allowed identification of potential PLCγ2 activators and inhibitors, thus demonstrating the feasibility of this approach for high-throughput screening.
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Affiliation(s)
- Ramya Visvanathan
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA; Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Tadanobu Utsuki
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA
| | - Daniel E Beck
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA
| | - Emma Lendy
- IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA; Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Kuai-Lin Sun
- Cayman Chemical Company, 1180 East Ellsworth Road, Ann Arbor, MI 48108, USA
| | - Yinghui Liu
- Cayman Chemical Company, 1180 East Ellsworth Road, Ann Arbor, MI 48108, USA
| | - Kirk W Hering
- Cayman Chemical Company, 1180 East Ellsworth Road, Ann Arbor, MI 48108, USA
| | - Andrew Mesecar
- IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA; Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Zhong-Yin Zhang
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA; Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Karson S Putt
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA.
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Prawiro C, Bunney TD, Kampyli C, Yaguchi H, Katan M, Bangham CRM. A frequent PLCγ1 mutation in adult T-cell leukemia/lymphoma determines functional properties of the malignant cells. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166601. [PMID: 36442790 DOI: 10.1016/j.bbadis.2022.166601] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/27/2022] [Accepted: 11/08/2022] [Indexed: 11/26/2022]
Abstract
BACKGROUND Development of adult T-cell leukemia/lymphoma (ATL) involves human T-cell leukemia virus type 1 (HTLV-1) infection and accumulation of somatic mutations. The most frequently mutated gene in ATL (36 % of cases) is phospholipase C gamma1 (PLCG1). PLCG1 is also frequently mutated in other T-cell lymphomas. However, the functional consequences of the PLCG1 mutations in cancer cells have not been characterized. METHODS We compared the activity of the wild-type PLCγ1 with that of a mutant carrying a hot-spot mutation of PLCγ1 (S345F) observed in ATL, both in cells and in cell-free assays. To analyse the impact of the mutation on cellular properties, we quantified cellular proliferation, aggregation, chemotaxis and apoptosis by live cell-imaging in an S345F+ ATL-derived cell line (KK1) and a KK1 cell line in which we reverted the mutation to the wild-type sequence using CRISPR/Cas9 and homology-directed repair. FINDINGS The PLCγ1 S345F mutation results in an increase of basal PLC activity in vitro and in different cell types. This higher basal activity is further enhanced by upstream signalling. Reversion of the S345F mutation in the KK1 cell line resulted in reduction of the PLC activity, lower rates of proliferation and aggregation, and a marked reduction in chemotaxis towards CCL22. The PLCγ1-pathway inhibitors ibrutinib and ritonavir reduced both the PLC activity and the tested functions of KK1 cells. INTERPRETATION Consistent with observations from clinical studies, our data provide direct evidence that activated variants of the PLCγ1 enzyme contribute to the properties of the malignant T-cell clone in ATL. FUNDING MRC (UK) Project Grant (P028160).
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Affiliation(s)
- Christy Prawiro
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, UK
| | - Tom D Bunney
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
| | - Charis Kampyli
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
| | - Hiroko Yaguchi
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, UK
| | - Matilda Katan
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK.
| | - Charles R M Bangham
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, UK.
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6
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Prakaash D, Fagnen C, Cook GP, Acuto O, Kalli AC. Molecular dynamics simulations reveal membrane lipid interactions of the full-length lymphocyte specific kinase (Lck). Sci Rep 2022; 12:21121. [PMID: 36476673 PMCID: PMC9729596 DOI: 10.1038/s41598-022-25603-6] [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: 05/18/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
The membrane-bound lymphocyte-specific protein-tyrosine kinase (Lck) triggers T cell antigen receptor signalling to initiate adaptive immune responses. Despite many structure-function studies, the mode of action of Lck and the potential role of plasma membrane lipids in regulating Lck's activity remains elusive. Advances in molecular dynamics simulations of membrane proteins in complex lipid bilayers have opened a new perspective in gathering such information. Here, we have modelled the full-length Lck open and closed conformations using data available from different crystalographic studies and simulated its interaction with the inner leaflet of the T cell plasma membrane. In both conformations, we found that the unstructured unique domain and the structured domains including the kinase interacted with the membrane with a preference for PIP lipids. Interestingly, our simulations suggest that the Lck-SH2 domain interacts with lipids differently in the open and closed Lck conformations, demonstrating that lipid interaction can potentially regulate Lck's conformation and in turn modulate T cell signalling. Additionally, the Lck-SH2 and kinase domain residues that significantly contacted PIP lipids are found to be conserved among the Src family of kinases, thereby potentially representing similar PIP interactions within the family.
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Affiliation(s)
- Dheeraj Prakaash
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Charline Fagnen
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Graham P Cook
- School of Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Antreas C Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK.
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK.
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