Bacterial endotoxin is able to modulate the expression of genes linked to iron in two Antarctic fish

The innate immunity can induce iron deprivation as a defense mechanism against potential bacterial pathogens, but little information is available as to its role in Antarctic fish. The authors of this study evaluated the response of iron metabolism related genes in liver and head-kidney of two Antarctic notothenioids Nototheniacoriiceps and Nototheniarossii.

The experiment lasted 7 days and were performed two intraperitoneal injections with saline buffer (control) or bacterial endotoxin from Escherichiacoli (lipopolysaccharide, LPS) at day 0 and day 2. After 5 days from the second injection, the fish were euthanatized, and plasma and two immune tissues (liver and head-kidney) were collected.The principal findings showed that the average plasma Fe2+ ion concentration was unaffected by treatment in any of the species. However, the gene expression response to LPS varied between tissues and species, being stronger in N.coriiceps and more prominent in the head-kidney than liver. The reaction to LPS was marked by increased individual variability in most genes analyzed, even when the change in expression was not statistically significant, suggesting different individual sensitivity and coping responses in these wild fish.ens.

Main component regression in two dimensions (PC1 and PC2) with the confidence ellipses (95%) and respective centroids between the control and LPS groups, in liver (A) and kidney (B) of N. coriiceps and, liver (C) and kidney (D) of N. rossii.N. rossii.

Authors also found that iron related genes had an attenuated and homogenous response to LPS but there was no detectable relationship between plasma Fe2+ ion and gene expression. As conclusion, in both tissues and species LPS exposure set a multilevel response that concur to promote intracellular accumulation of iron, an indication that Antarctic Notothenoids use innate nutritional immunity as a resistance mechanism against pathogens.


Source: Martínez, D. P., Sousa, C., Oyarzún, R., Pontigo, J. P., Canario, A. V. M., Power, D. M., et al. (2020). LPS Modulates the Expression of Iron-Related Immune Genes in Two Antarctic Notothenoids. Front. Physiol. 11, 102. DOI: 10.3389/fphys.2020.00102

Author: Cármen Sousa


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