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Frei MS, Mehta S, Zhang J. Next-Generation Genetically Encoded Fluorescent Biosensors Illuminate Cell Signaling and Metabolism. Annu Rev Biophys 2024; 53:275-297. [PMID: 38346245 DOI: 10.1146/annurev-biophys-030722-021359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Genetically encoded fluorescent biosensors have revolutionized the study of cell signaling and metabolism, as they allow for live-cell measurements with high spatiotemporal resolution. This success has spurred the development of tailor-made biosensors that enable the study of dynamic phenomena on different timescales and length scales. In this review, we discuss different approaches to enhancing and developing new biosensors. We summarize the technologies used to gain structural insights into biosensor design and comment on useful screening technologies. Furthermore, we give an overview of different applications where biosensors have led to key advances over recent years. Finally, we give our perspective on where future work is bound to make a large impact.
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Affiliation(s)
- Michelle S Frei
- Department of Pharmacology, University of California San Diego, La Jolla, California, USA; , ,
| | - Sohum Mehta
- Department of Pharmacology, University of California San Diego, La Jolla, California, USA; , ,
| | - Jin Zhang
- Department of Pharmacology, University of California San Diego, La Jolla, California, USA; , ,
- Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, La Jolla, California, USA
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
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Dienel GA, Rothman DL. In vivo calibration of genetically encoded metabolite biosensors must account for metabolite metabolism during calibration and cellular volume. J Neurochem 2024; 168:506-532. [PMID: 36726217 DOI: 10.1111/jnc.15775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/21/2023] [Accepted: 01/28/2023] [Indexed: 02/03/2023]
Abstract
Isotopic assays of brain glucose utilization rates have been used for more than four decades to establish relationships between energetics, functional activity, and neurotransmitter cycling. Limitations of these methods include the relatively long time (1-60 min) for the determination of labeled metabolite levels and the lack of cellular resolution. Identification and quantification of fuels for neurons and astrocytes that support activation and higher brain functions are a major, unresolved issues. Glycolysis is preferentially up-regulated during activation even though oxygen level and supply are adequate, causing lactate concentrations to quickly rise during alerting, sensory processing, cognitive tasks, and memory consolidation. However, the fate of lactate (rapid release from brain or cell-cell shuttling coupled with local oxidation) is long disputed. Genetically encoded biosensors can determine intracellular metabolite concentrations and report real-time lactate level responses to sensory, behavioral, and biochemical challenges at the cellular level. Kinetics and time courses of cellular lactate concentration changes are informative, but accurate biosensor calibration is required for quantitative comparisons of lactate levels in astrocytes and neurons. An in vivo calibration procedure for the Laconic lactate biosensor involves intracellular lactate depletion by intravenous pyruvate-mediated trans-acceleration of lactate efflux followed by sensor saturation by intravenous infusion of high doses of lactate plus ammonium chloride. In the present paper, the validity of this procedure is questioned because rapid lactate-pyruvate interconversion in blood, preferential neuronal oxidation of both monocarboxylates, on-going glycolytic metabolism, and cellular volumes were not taken into account. Calibration pitfalls for the Laconic lactate biosensor also apply to other metabolite biosensors that are standardized in vivo by infusion of substrates that can be metabolized in peripheral tissues. We discuss how technical shortcomings negate the conclusion that Laconic sensor calibrations support the existence of an in vivo astrocyte-neuron lactate concentration gradient linked to lactate shuttling from astrocytes to neurons to fuel neuronal activity.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | - Douglas L Rothman
- Magnetic Resonance Research Center and Departments of Radiology and Biomedical Engineering, Yale University, New Haven, Connecticut, USA
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Arumugam P, Kielian T. Metabolism Shapes Immune Responses to Staphylococcus aureus. J Innate Immun 2023; 16:12-30. [PMID: 38016430 PMCID: PMC10766399 DOI: 10.1159/000535482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/21/2023] [Indexed: 11/30/2023] Open
Abstract
BACKGROUND Staphylococcus aureus (S. aureus) is a common cause of hospital- and community-acquired infections that can result in various clinical manifestations ranging from mild to severe disease. The bacterium utilizes different combinations of virulence factors and biofilm formation to establish a successful infection, and the emergence of methicillin- and vancomycin-resistant strains introduces additional challenges for infection management and treatment. SUMMARY Metabolic programming of immune cells regulates the balance of energy requirements for activation and dictates pro- versus anti-inflammatory function. Recent investigations into metabolic adaptations of leukocytes and S. aureus during infection indicate that metabolic crosstalk plays a crucial role in pathogenesis. Furthermore, S. aureus can modify its metabolic profile to fit an array of niches for commensal or invasive growth. KEY MESSAGES Here we focus on the current understanding of immunometabolism during S. aureus infection and explore how metabolic crosstalk between the host and S. aureus influences disease outcome. We also discuss how key metabolic pathways influence leukocyte responses to other bacterial pathogens when information for S. aureus is not available. A better understanding of how S. aureus and leukocytes adapt their metabolic profiles in distinct tissue niches may reveal novel therapeutic targets to prevent or control invasive infections.
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Affiliation(s)
- Prabhakar Arumugam
- Department of Pathology, Microbiology, and Immunology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Tammy Kielian
- Department of Pathology, Microbiology, and Immunology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Scandella V, Petrelli F, Moore DL, Braun SMG, Knobloch M. Neural stem cell metabolism revisited: a critical role for mitochondria. Trends Endocrinol Metab 2023; 34:446-461. [PMID: 37380501 DOI: 10.1016/j.tem.2023.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/30/2023]
Abstract
Metabolism has emerged as a key regulator of stem cell behavior. Mitochondria are crucial metabolic organelles that are important for differentiated cells, yet considered less so for stem cells. However, recent studies have shown that mitochondria influence stem cell maintenance and fate decisions, inviting a revised look at this topic. In this review, we cover the current literature addressing the role of mitochondrial metabolism in mouse and human neural stem cells (NSCs) in the embryonic and adult brain. We summarize how mitochondria are implicated in fate regulation and how substrate oxidation affects NSC quiescence. We further explore single-cell RNA sequencing (scRNA-seq) data for metabolic signatures of adult NSCs, highlight emerging technologies reporting on metabolic signatures, and discuss mitochondrial metabolism in other stem cells.
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Affiliation(s)
- Valentina Scandella
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Francesco Petrelli
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Darcie L Moore
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
| | - Simon M G Braun
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland
| | - Marlen Knobloch
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.
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Smith M, Zhang L, Jin Y, Yang M, Bade A, Gillis KD, Jana S, Bypaneni RN, Glass TE, Lin H. A Turn-On Fluorescent Amino Acid Sensor Reveals Chloroquine's Effect on Cellular Amino Acids via Inhibiting Cathepsin L. ACS CENTRAL SCIENCE 2023; 9:980-991. [PMID: 37252359 PMCID: PMC10214525 DOI: 10.1021/acscentsci.2c01325] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Indexed: 05/31/2023]
Abstract
Maintaining homeostasis of metabolites such as amino acids is critical for cell survival. Dysfunction of nutrient balance can result in human diseases such as diabetes. Much remains to be discovered about how cells transport, store, and utilize amino acids due to limited research tools. Here we developed a novel, pan-amino acid fluorescent turn-on sensor, NS560. It detects 18 of the 20 proteogenic amino acids and can be visualized in mammalian cells. Using NS560, we identified amino acids pools in lysosomes, late endosomes, and surrounding the rough endoplasmic reticulum. Interestingly, we observed amino acid accumulation in large cellular foci after treatment with chloroquine, but not with other autophagy inhibitors. Using a biotinylated photo-cross-linking chloroquine analog and chemical proteomics, we identified Cathepsin L (CTSL) as the chloroquine target leading to the amino acid accumulation phenotype. This study establishes NS560 as a useful tool to study amino acid regulation, identifies new mechanisms of action of chloroquine, and demonstrates the importance of CTSL regulation of lysosomes.
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Affiliation(s)
- Michael
R. Smith
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
| | - Le Zhang
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Yizhen Jin
- Graduate
Program of Biochemistry, Molecular and Cell Biology, Department of
Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United
States
| | - Min Yang
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
| | - Anusha Bade
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Kevin D. Gillis
- Dalton
Cardiovascular Research Center, Department of Bioengineering and Department
of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65211, United States
| | - Sadhan Jana
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
| | - Ramesh Naidu Bypaneni
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Timothy E. Glass
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Hening Lin
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
- Howard
Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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Application of Metabolic Reprogramming to Cancer Imaging and Diagnosis. Int J Mol Sci 2022; 23:ijms232415831. [PMID: 36555470 PMCID: PMC9782057 DOI: 10.3390/ijms232415831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/12/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Cellular metabolism governs the signaling that supports physiological mechanisms and homeostasis in an individual, including neuronal transmission, wound healing, and circadian clock manipulation. Various factors have been linked to abnormal metabolic reprogramming, including gene mutations, epigenetic modifications, altered protein epitopes, and their involvement in the development of disease, including cancer. The presence of multiple distinct hallmarks and the resulting cellular reprogramming process have gradually revealed that these metabolism-related molecules may be able to be used to track or prevent the progression of cancer. Consequently, translational medicines have been developed using metabolic substrates, precursors, and other products depending on their biochemical mechanism of action. It is important to note that these metabolic analogs can also be used for imaging and therapeutic purposes in addition to competing for metabolic functions. In particular, due to their isotopic labeling, these compounds may also be used to localize and visualize tumor cells after uptake. In this review, the current development status, applicability, and limitations of compounds targeting metabolic reprogramming are described, as well as the imaging platforms that are most suitable for each compound and the types of cancer to which they are most appropriate.
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