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Iglesias-Artola JM, Nadler A. The Road to Quantitative Lipid Biochemistry in Living Cells. Acc Chem Res 2023; 56:810-820. [PMID: 36943016 PMCID: PMC10077588 DOI: 10.1021/acs.accounts.2c00804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
ConspectusTraditional cell biological techniques are not readily suitable for studying lipid signaling events because genetic perturbations are much slower than the interconversion of lipids in complex metabolic networks. For this reason, novel chemical biological approaches have been developed. One approach is to chemically modify a lipid with a so-called "caging group" that renders it inactive, but this cage can be removed photochemically inside cells to release the bioactive molecule. These caged compounds offer unique advantages for studying the kinetics of cellular biochemistry and have been extensively used in the past. However, a limitation of conventional caged compounds is their ability to diffuse freely inside the cell, which does not permit localized activation below optical precision. This poses a challenge for studying lipid signaling as lipid function inside cells is tightly linked to their parent membrane. An ideal lipid probe should, therefore, be restricted to a single organelle membrane or preferentially to a single leaflet. We first demonstrated the plasma-membrane-specific photorelease of fatty acids by employing sulfonated caging groups. Using these caged fatty acid probes we demonstrated that lipid localization determines signaling outcome. Generalizing this approach, we designed a so-called "click cage" that can be coupled to lipids and offers the possibility to attach organelle targeting groups via click chemistry. Using this strategy, we have synthesized plasma membrane, lysosomal, mitochondria, and endoplasmic-reticulum-targeted lipids that can be used to dissect organelle-specific signaling events. To reduce the synthetic effort associated with generating caged compounds, we designed a coumarin triflate reagent that allows the direct functionalization of phosphate- or carboxylate-containing compounds. With this novel reagent, we synthesized a small library of photocaged G-protein-coupled receptor (GPCR) ligands to study the underlying lipid signaling dynamics. Most recently, we have focused on quantifying the kinetics of lipid signaling for different diacylglycerol (DAG) species using plasma-membrane-targeted caged DAGs. Using this approach, we quantitatively measured lipid-protein affinities and lipid transbilayer dynamics in living cells. After analyzing DAGs with different acyl chain length and saturation degree, we discovered that affinities can vary by up to an order of magnitude. This finding clearly shows that cells are able to distinguish between individual DAG species, thereby demonstrating that lipid diversity matters in cellular signal processing. Although the recent advances have yielded valuable tools to study lipid signaling, challenges remain on specifically targeting the different leaflets of organelle membranes. Furthermore, it is necessary to simplify the experimental approaches required for parametrizing and corroborating quantitative kinetic models of lipid signaling. In the future, we envision that the application of leaflet-specific caged lipids to model membrane systems will be of crucial importance for understanding lipid asymmetry.
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Affiliation(s)
- Juan M Iglesias-Artola
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
| | - André Nadler
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
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Jiménez-López C, Nadler A. Caged lipid probes for controlling lipid levels on subcellular scales. Curr Opin Chem Biol 2023; 72:102234. [PMID: 36493527 DOI: 10.1016/j.cbpa.2022.102234] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/26/2022] [Accepted: 11/07/2022] [Indexed: 12/12/2022]
Abstract
Lipids exert their cellular functions in individual organelles, in some cases on the scale of even smaller, specialized membrane domains. Thus, the experimental capacity to precisely manipulate lipid levels at the subcellular level is crucial for studying lipid-related processes in cell biology. Photo-caged lipid probes which partition into specific cellular membranes prior to photoactivation have emerged as key tools for localized and selective perturbation of lipid concentration in living cells. In this review, we provide an overview of the recent advances in the area and outline which developments are still required for the methodology to be more widely implemented in the wider membrane biology community.
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Affiliation(s)
| | - André Nadler
- Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany.
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Tei R, Morstein J, Shemet A, Trauner D, Baskin JM. Optical Control of Phosphatidic Acid Signaling. ACS CENTRAL SCIENCE 2021; 7:1205-1215. [PMID: 34345670 PMCID: PMC8323247 DOI: 10.1021/acscentsci.1c00444] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Indexed: 05/31/2023]
Abstract
Phosphatidic acids (PAs) are glycerophospholipids that regulate key cell signaling pathways governing cell growth and proliferation, including the mTOR and Hippo pathways. Their acyl chains vary in tail length and degree of saturation, leading to marked differences in the signaling functions of different PA species. For example, in mTOR signaling, saturated forms of PA are inhibitory, whereas unsaturated forms are activating. To enable rapid control over PA signaling, we describe here the development of photoswitchable analogues of PA, termed AzoPA and dAzoPA, that contain azobenzene groups in one or both lipid tails, respectively. These photolipids enable optical control of their tail structure and can be reversibly switched between a straight trans form and a relatively bent cis form. We found that cis-dAzoPA selectively activates mTOR signaling, mimicking the bioactivity of unsaturated forms of PA. Further, in the context of Hippo signaling, whose growth-suppressing activity is blocked by PA, we found that the cis forms of both AzoPA and dAzoPA selectively inhibit this pathway. Collectively, these photoswitchable PA analogues enable optical control of mTOR and Hippo signaling, and we envision future applications of these probes to dissect the pleiotropic effects of physiological and pathological PA signaling.
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Affiliation(s)
- Reika Tei
- Department
of Chemistry and Chemical Biology and Weill Institute for Cell and
Molecular Biology, Cornell University, Ithaca, New York 14850, United States
| | - Johannes Morstein
- Department
of Chemistry, New York University, New York, New York 10003, United States
| | - Andrej Shemet
- Department
of Chemistry, New York University, New York, New York 10003, United States
| | - Dirk Trauner
- Department
of Chemistry, New York University, New York, New York 10003, United States
| | - Jeremy M. Baskin
- Department
of Chemistry and Chemical Biology and Weill Institute for Cell and
Molecular Biology, Cornell University, Ithaca, New York 14850, United States
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Morstein J, Dacheux MA, Norman DD, Shemet A, Donthamsetti PC, Citir M, Frank JA, Schultz C, Isacoff EY, Parrill AL, Tigyi GJ, Trauner D. Optical Control of Lysophosphatidic Acid Signaling. J Am Chem Soc 2020; 142:10612-10616. [PMID: 32469525 DOI: 10.1021/jacs.0c02154] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Lysophosphatidic acid (LPA) is a phospholipid that acts as an extracellular signaling molecule and activates the family of lysophosphatidic acid receptors (LPA1-6). These G protein-coupled receptors (GPCRs) are broadly expressed and are particularly important in development as well as in the nervous, cardiovascular, reproductive, gastrointestinal, and pulmonary systems. Here, we report on a photoswitchable analogue of LPA, termed AzoLPA, which contains an azobenzene photoswitch embedded in the acyl chain. AzoLPA enables optical control of LPA receptor activation, shown through its ability to rapidly control LPA-evoked increases in intracellular Ca2+ levels. AzoLPA shows greater activation of LPA receptors in its light-induced cis-form than its dark-adapted (or 460 nm light-induced) trans-form. AzoLPA enabled the optical control of neurite retraction through its activation of the LPA2 receptor.
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Affiliation(s)
- Johannes Morstein
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Mélanie A Dacheux
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee 39163, United States
| | - Derek D Norman
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee 39163, United States
| | - Andrej Shemet
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Prashant C Donthamsetti
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, United States
| | - Mevlut Citir
- European Molecular Biology Laboratory (EMBL), Heidelberg 69117, Germany
| | - James A Frank
- Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Carsten Schultz
- European Molecular Biology Laboratory (EMBL), Heidelberg 69117, Germany.,Chemical Physiology & Biochemistry Department, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Ehud Y Isacoff
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California 94720, United States
| | - Abby L Parrill
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38152, United States
| | - Gabor J Tigyi
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee 39163, United States
| | - Dirk Trauner
- Department of Chemistry, New York University, New York, New York 10003, United States
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Berizzi AE, Goudet C. Strategies and considerations of G-protein-coupled receptor photopharmacology. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2020; 88:143-172. [PMID: 32416866 DOI: 10.1016/bs.apha.2019.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
G-protein-coupled receptor (GPCR) pharmacology tends to be complex and at times poorly understood. This has led to the development of GPCR-targeting agents that often demonstrate poor pharmacokinetic properties and poor selectivity for their target receptors. One approach that is emerging as a means of addressing these limitations is the use of molecules whose activity can be controlled by light. Photopharmacology involves the incorporation of a photoswitch into the structure of a given compound, cage or linker and following irradiation with light, undergoes a structural rearrangement, which changes its biological activity. The use of light-regulated ligands offers the opportunity to modulate and understand GPCR signaling in a more spatiotemporal manner than classical pharmacological approaches. In this chapter we will discuss some of the advancements that have been made in photopharmacology, particularly in developing photoswitchable ligands that target class A GPCRs, e.g., muscarinic acetylcholine receptors, class B GPCRs, e.g., glucagon-like peptide-1 receptor, and class C GPCRs, e.g., metabotrobic glutamate receptors. Given the intricacy of GPCR pharmacology, this chapter will also discuss some of the challenges the field faces when designing photopharmacological tools. Furthermore, it will propose that it is with a full appreciation of the spectrum of pharmacological and pharmacokinetic properties of photoswitchable ligands that research will be better placed to develop ligands with a reduced risk of failure during preclinical progression. This will likely enable photopharmacological approaches to continue to find novel applications and offer new perspectives in understanding (patho)physiology to ultimately inform future GPCR drug discovery efforts.
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Affiliation(s)
- Alice E Berizzi
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, France.
| | - Cyril Goudet
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, France.
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Wagner N, Schuhmacher M, Lohmann A, Nadler A. A Coumarin Triflate Reagent Enables One-Step Synthesis of Photo-Caged Lipid Metabolites for Studying Cell Signaling. Chemistry 2019; 25:15483-15487. [PMID: 31461184 PMCID: PMC6916161 DOI: 10.1002/chem.201903909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Indexed: 12/31/2022]
Abstract
Photorelease of caged compounds is among the most powerful experimental approaches for studying cellular functions on fast timescales. However, its full potential has yet to be exploited, as the number of caged small molecules available for cell biological studies has been limited by synthetic challenges. Addressing this problem, a straightforward, one‐step procedure for efficiently synthesizing caged compounds was developed. An in situ generated benzylic coumarin triflate reagent was used to specifically functionalize carboxylate and phosphate moieties in the presence of free hydroxy groups, generating various caged lipid metabolites, including a number of GPCR ligands. By combining the photo‐caged ligands with the respective receptors, an easily implementable experimental platform for the optical control and analysis of GPCR‐mediated signal transduction in living cells was developed. Ultimately, the described synthetic strategy allows rapid generation of photo‐caged small molecules and thus greatly facilitates the analysis of their biological roles in live cell microscopy assays.
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Affiliation(s)
- Nicolai Wagner
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
| | - Milena Schuhmacher
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
| | - Annett Lohmann
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
| | - André Nadler
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
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