Curcumin effect on Acanthamoeba triangularis encystation under nutrient starvation

• Published in: PeerJ (San Francisco, CA) CA), 2022-07, Vol.10, p.e13657-e13657, Article e13657
• Main Authors: Boonhok, Rachasak, Sangkanu, Suthinee, Phumjan, Suganya, Jongboonjua, Ramita, Sangnopparat, Nawarat, Kwankaew, Pattamaporn, Tedasen, Aman, Lim, Chooi Ling, Pereira, Maria de Lourdes, Rahmatullah, Mohammed, Wilairatana, Polrat, Wiart, Christophe, Dolma, Karma G, Paul, Alok K, Gupta, Madhu, Nissapatorn, Veeranoot
• Format: Article
• Language: English
• Subjects: Acanthamoeba; Acanthamoeba - genetics; Acanthamoeba triangularis; Amoeba; Analysis; Animals; Autophagy; Cell Biology; Cellulose; Cellulose synthase; Curcumin; Curcumin - pharmacology; Cysts; Encystation; Experiments; Gene expression; Genetic transcription; Glucose; Humans; Infections; Laboratories; Life sciences; Microbiology; Molecular Biology; Nutrient Starvation; Parasites; Parasitology; Physiological aspects; Proteins; Real-time PCR; RNA; Serine proteinase; Starvation; Trophozoites; Trophozoites - physiology
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.13657

Curcumin is an active compound derived from turmeric, , and is known for its benefits to human health. The amoebicidal activity of curcumin against was recently discovered. However, a physiological change of intracellular pathways related to encystation mechanism, including autophagy in the surviving amoeba after curcumin treatment, has never been reported. This study aims to investigate the effect of curcumin on the survival of under nutrient starvation and nutrient-rich condition, as well as to evaluate the encystation and a physiological change of autophagy at the mRNA level. In this study, amoebas were treated with a sublethal dose of curcumin under nutrient starvation and nutrient-rich condition and the surviving amoebas was investigated. Cysts formation and vacuolization were examined by microscopy and transcriptional expression of autophagy-related genes and other encystation-related genes were evaluated by real-time PCR. cysts were formed under nutrient starvation. However, in the presence of the autophagy inhibitor, 3-methyladenine (3-MA), the percentage of cysts was significantly reduced. Interestingly, in the presence of curcumin, most of the parasites remained in the trophozoite stage in both the starvation and nutrient-rich condition. In vacuolization analysis, the percentage of amoebas with enlarged vacuole was increased upon starvation. However, the percentage was significantly declined in the presence of curcumin and 3-MA. Molecular analysis of autophagy-related (ATG) genes showed that the mRNA expression of the ATG genes, ATG3, ATG8b, ATG12, ATG16, under the starvation with curcumin was at a basal level along the treatment. The results were similar to those of the curcumin-treated amoebas under a nutrient-rich condition, except ATG16 which increased later. On the other hand, mRNA expression of encystation-related genes, cellulose synthase and serine proteinase, remained unchanged during the first 18 h, but significantly increased at 24 h post treatment. Curcumin inhibits cyst formation in surviving trophozoites, which may result from its effect on mRNA expression of key ATG-related genes. However, further investigation into the mechanism of curcumin in trophozoites arrest and its association with autophagy or other encystation-related pathways is needed to support the future use of curcumin.