Combined antiparasitic and anti‐inflammatory effects of the natural polyphenol curcumin on turbot scuticociliatosis

Abstract

The histiophagous scuticociliate Philasterides dicentrarchi is the aetiological agent of scuticociliatosis, a parasitic disease of farmed turbot. Curcumin, a polyphenol from Curcuma longa (turmeric), is known to have antioxidant and anti-inflammatory properties. We investigated the in vitro effects of curcumin on the growth of P. dicentrarchi and on the production of pro-inflammatory cytokines in turbot leucocytes activated by parasite cysteine proteases. At 100 μm, curcumin had a cytotoxic effect and completely inhibited the growth of the parasite. At 50 μm, curcumin inhibited the protease activity of the parasite and expression of genes encoding two virulence-associated proteases: leishmanolysin-like peptidase and cathepsin L-like. At concentrations between 25 and 50 μm, curcumin inhibited the expression of S-adenosyl-L-homocysteine hydrolase, an enzyme involved in the biosynthesis of the amino acids methionine and cysteine. At 100 μm, curcumin inhibited the expression of the cytokines tumour necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) produced in turbot leucocytes activated by parasite proteases. Results show that curcumin has a dual effect on scuticociliatosis: an antiparasitic effect on the catabolism and anabolism of ciliate proteins, and an anti-inflammatory effect that inhibits the production of proinflammatory cytokines in the host. The present findings suggest the potential usefulness of this polyphenol in treating scuticociliatosis.

Interactions between the Parasite Philasterides dicentrarchi and the Immune System of the Turbot Scophthalmus maximus. A Transcriptomic Analysis

“…The complement system is considered important in defence against P. dicentrarchi [11,20], and although complement levels are lowered in the serum of infected turbot [12], it is not known whether leishmanolysins participate in the process. Our results agree with those obtained in previous studies, which reported high level of leishmanolysin expression in a P. dicentrarchi isolate (I1) obtained from turbot infections [43], and UR of several leishmanolysin genes in Miamiensis avidus fed a cell line [44], suggesting that these molecules play a role in cell degradation. Thus, although the role of each regulated leishmanolysin gene in the success of P. dicentrachi infection remains to be established, it appears that leishmanolysins are probably involved in ciliate virulence.…”

In Vitro Testing of Alternative Synthetic and Natural Antiparasitic Compounds against the Monogenean Sparicotyle chrysophrii

“…has been previously tested in fish feed as an immunostimulator and booster in the antioxidant status and protein content [ 37 , 38 ]. Although it has been employed against many protozoan and few trematode infections in humans over the years [ 39 ], it has been recently introduced in aquaculture as an experimental and efficient treatment of the ciliates Ichthyophthirius multifiliis infecting carp [ 40 ] and Philasterides dicentrarchi infecting turbot [ 41 ].…”

Dual RNA-Seq Unveils Pseudomonas plecoglossicida htpG Gene Functions During Host-Pathogen Interactions With Epinephelus coioides

“…IL-6 as a key member of cytokines plays key roles in immune process, including acute phase response, hematopoiesis, energy sensor, and immune cell differentiation through modulating immune-signaling pathways (51, 52). Simultaneously, as a pro-inflammatory factor, up-regulation of IL-6 transcripts was detected in many fish defending against various pathogenic infections (53–55). Furthermore, IL-6 was found to drive lymphocyte differentiation after stimulation of trout head-kidney cells (56), indicating that it might be involved in fish immune response.…”