Insights into the cellular role of mammalian inositol pyrophosphates

Abstract: Inositol pyrophosphates (PP-IPs) are highly energetic signalling molecules regulating central physiological processes in mammals. As their biosynthesis is tightly connected to cellular energy homeostasis, an increasing number of reports show the involvement of these messengers in metabolic disorders, including type 2 diabetes and hyperphosphatemia. Experiments performed in yeast indicated an activation of the PP-IP pathway caused by reactive oxygen species (ROS). Moreover, since the PP-IPs have been shown to interact with synaptic vesicle fusion proteins, they have also been implicated in the regulation of neuroexocytosis. However, the precise function of PP-IPs in response to oxidative stress and during synaptic vesicle fusion events remained elusive. Here, a technique relying on PP-IP prometabolites and a capillary electrophoresis electrospray ionization mass spectrometry (CE-ESI-MS) method are used to investigate the role of PP-IPs during neurotransmission and to examine their modulation via ROS. Cellular uptake and photorelease of PP-IPs from synthetic prometabolites were verified by polyacrylamide gel electrophoresis (PAGE), allowing to exploit such prometabolite strategy for investigating the function of PP-IPs during synaptic vesicle fusion events. Moreover, a PP-IP enrichment protocol was combined with CE-ESI-MS and revealed that PP-IP levels in mammalian cells are decreasing in response to extracellular and endogenous ROS. Application of quinone drugs, particularly β-lapachone (β-lap), under normoxic and hypoxic conditions enabled to produce ROS in cellulo and demonstrated that β-lap exposure caused PP-IP changes that are O2-dependent. Experiments in cells devoid of the β-lap metabolizing enzyme NAD(P)H:quinone oxidoreductase-1 (NQO1) showed that β-lap requires NQO1 to regulate PP-IP metabolism, while a decline in the energy status of the cell related to β-lap treatment was NQO1-independent. The data presented here provide insight into the potential of PAGE and CE-ESI-MS for the analysis of PP-IPs and identifies the prometabolite technology as a useful tool to artificially increase the levels of distinct PP-IP isomers inside cells. Moreover, new aspects of β-lap pharmacology and its impacts on PP-IP metabolism are presented. The identification of different quinone drugs as modulators of PP-IP synthesis will allow to better appreciate their overall impact on cellular functions in mammals

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Dissertation, 2023

Klassifikation und Themen

• Klassifikation: Biowissenschaften, Biologie

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2023
• Urheber: Eisenbeis, Verena B.
• Beteiligte Personen und Organisationen: Jessen, Henning Jacob ; Jessen, Henning Jacob ; Friedrich, Thorsten ; Albert-Ludwigs-Universität Freiburg. Fakultät für Chemie und Pharmazie ; Albert-Ludwigs-Universität Freiburg. Fakultät für Chemie und Pharmazie

Weitere Informationen

• DOI: 10.6094/UNIFR/236939
• URN: urn:nbn:de:bsz:25-freidok-2369394
• Rechteinformation: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 25.03.2025, 13:49 MEZ