Carbamoyl-Phosphate Synthase 1 as a Novel Target of Phomoxanthone A, a Bioactive Fungal Metabolite

Abstract

Phomoxanthone A, a bioactive xanthone dimer isolated from the endophytic fungus Phomopsis sp., is a mitochondrial toxin weakening cellular respiration and electron transport chain activity by a fast breakup of the mitochondrial assembly. Here, a multi-disciplinary strategy has been developed and applied for identifying phomoxanthone A target(s) to fully address its mechanism of action, based on drug affinity response target stability and targeted limited proteolysis. Both approaches point to the identification of carbamoyl-phosphate synthase 1 as a major phomoxanthone A target in mitochondria cell lysates, giving also detailed insights into the ligand/target interaction sites by molecular docking and assessing an interesting phomoxanthone A stimulating activity on carbamoyl-phosphate synthase 1. Thus, phomoxanthone A can be regarded as an inspiring molecule for the development of new leads in counteracting hyperammonemia states.

A Proteomic Platform Unveils the Brain Glycogen Phosphorylase as a Potential Therapeutic Target for Glioblastoma Multiforme

“…Nowadays, it is generally accepted that poly-pharmacological drugs profile can produce additive or synergistic actions while reducing side effects and significantly contribute to the high therapeutic success and, in this scenario, the functional proteomics-based identification of drug targets covers a key role [ 12 ]. Recently, new strategies have been developed and applied for the identification of the protein partners of free bioactive small molecules, such as SPROX (Stability of Proteins from Rates of Oxidation), TPP (Thermal Proteome Profiling), CETSA (Cellular Thermal Shift Assay) and DARTS, which has been applied in this paper [ 13 , 14 ]. The DARTS strategy functions due to the ability of a small molecule to increase the stability of the interacting target(s) towards enzymatic proteolysis; this particular behavior can be revealed by Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and the target(s) can be identified by a classical proteomics analysis.…”

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“…Similarly, limited proteolysis-coupled mass spectrometry (LiP-MS) measures proteolytic peptides that play as reporters to determine which protein regions are hugely affected by the NP interaction ( Morretta et al, 2017 ; Schopper et al, 2017 ; Del Gaudio et al, 2018 ; Hwang et al, 2020 ). In this work, we applied our consolidated DARTS and LIP-MS platform ( Ceccacci et al, 2020 ; Morretta et al, 2021a ) to disclose the interactome of an attractive bioactive NP such as artemetin (ART), a 5-hydroxy-3,6,7,3′,4′-pentamethoxyflavone ( Figure 1A ) found in many different medicinal plants such as Achillea millefolium L. , Artemisia absinthium , Artemisia gorgonum , Cordia verbenacea , Vitex trifolia , and Vitex negundo ( Ortet et al, 2008 ; De Souza et al, 2011 ; De Almeida et al, 2016 ; Wee et al, 2020 ; Martim et al, 2021 ; Sichaem et al, 2021 ).…”

Phomoxanthone A Targets ATP Synthase

“…Phomoxanthone A (1) is a naturally occurring dimeric tetrahydroxanthone that possesses both an enticing molecular architecture and impressive biological properties (Figure 1). [1][2][3][4][5][6][7][8][9][10] For example, phomoxanthone A is known to have antibacterial, antimalarial, and anticancer activity. It has been observed that 1 is equally as effective at killing both cisplatin sensitive and cisplatin resistant cancer cells.…”

“…[4] Follow up studies by Monti identified carbamoyl-phosphate synthase 1 as a possible target of phomoxanthone A. [6] A separate study by Chen and Luo identified phomoxanthone A as a protein tyrosine phosphatase inhibitor. [7] However, the role of these two biomolecular targets in affecting mitochondrial disintegration is unclear leaving open the possibility of phomoxanthone A having more direct target(s) in the mitochondria.…”

“…A 2018 study from Bohler and coworkers found that phomoxanthone A ( 1 ) causes rapid disintegration of the inner mitochondrial membrane, but it did not identify the biomolecular targets [4] . Follow up studies by Monti identified carbamoyl‐phosphate synthase 1 as a possible target of phomoxanthone A [6] . A separate study by Chen and Luo identified phomoxanthone A as a protein tyrosine phosphatase inhibitor [7] .…”