title: Sclerotiorin inhibits protein kinase G from Mycobacterium tuberculosis and impairs mycobacterial growth in macrophages.
abstract: As a eukaryotic-like Ser/Thr protein kinase, Mycobacterium tuberculosis virulent effector protein kinase G (PknG) mediates mycobacterial survival by regulating bacterial cell metabolic processes and preventing phagosome-lysosome fusion in host macrophages. Targeting PknG is an effective strategy for development of anti-tuberculosis (TB) drugs. In the study, we found that sclerotiorin, derived from marine fungi from the South China Sea, exhibited moderately strong inhibitory effects on recombinant PknG, with an IC50value of 76.5 μM, and acted as a non-competitive inhibitor. The dissociation constant (KD) of sclerotiorin determined by MST was 11.4 μM, demonstrating a moderate binding strength between them. Sclerotiorin could substantially impair the mycobacterial survival in infected macrophages while the macrophage viability remained unaffected, though it did not inhibit the mycobacterial growth in culture. When sclerotiorin was used in combination with rifampicin, intracellular mycobacterial growth decreased as sclerotiorin concentration increased. Docking analysis suggested a binding mechanism of inhibition with performing interactions with the P-loop and catalytic loop of PknG. In summary, we reported that sclerotiorin had moderately strong PknG inhibitory activity, but no cytotoxicity, and it could substantially decrease the mycobacterial growth inside macrophages, suggesting that sclerotiorin has potential to supplement antibiotic therapy for TB.
authors.affiliation: School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Biomedical Center, Sun Yat-sen University, Guangzhou 510275, China; South China Sea Resource Exploitation and Protection Collaborative Innovation Center (SCS-REPIC), Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Dongni
authors.initials: D
authors.lastname: Chen
authors.affiliation: School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Biomedical Center, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Ma
authors.affiliation: School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Biomedical Center, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Lei
authors.initials: L
authors.lastname: He
authors.affiliation: School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Biomedical Center, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Peibo
authors.initials: P
authors.lastname: Yuan
authors.affiliation: Biomedical Center, Sun Yat-sen University, Guangzhou 510275, China; South China Sea Resource Exploitation and Protection Collaborative Innovation Center (SCS-REPIC), Sun Yat-sen University, Guangzhou 510275, China; School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: She
authors.affiliation: School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Biomedical Center, Sun Yat-sen University, Guangzhou 510275, China; South China Sea Resource Exploitation and Protection Collaborative Innovation Center (SCS-REPIC), Sun Yat-sen University, Guangzhou 510275, China. Electronic address: luyj@mail.sysu.edu.cn.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000818:Animals; D000995:Antitubercular Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D058491:Bacterial Load; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D001578:Benzopyrans / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001665:Binding Sites; D004305:Dose-Response Relationship, Drug; D006367:HeLa Cells; D006801:Humans; D061986:MCF-7 Cells; D008264:Macrophages / Q000187:drug effects* / Q000382:microbiology; D051379:Mice; D062105:Molecular Docking Simulation; D058990:Molecular Targeted Therapy; D009163:Mycobacterium bovis / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D014376:Tuberculosis / Q000188:drug therapy* / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D001578:Benzopyrans; D047428:Protein Kinase Inhibitors; C101449:sclerotiorin; D017346:Protein Serine-Threonine Kinases; C000605609:protein kinase G, Mycobacterium tuberculosis
keywords: Anti-tuberculosis; Azaphilone; Inhibitors; Macrophages; Protein kinase G