|MARTINEZ, A - Crilar-Conicet: Regional Research Centre La Rioja|
Submitted to: Infection and Immunity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/22/2018
Publication Date: 4/24/2018
Citation: Elsasser, T.H., Miska, K.B., Kahl, S., Fetterer, R.H., Martinez, A. 2018. Temporal pattern changes in duodenal protein tyrosine nitration events in response to Eimeria acervulina infection in chickens. Infection and Immunity. https://doi.org:10.1093/jas/sky140.
Interpretive Summary: In the poultry industry, one of the greatest challenges is maintaining good health of the chickens that are reared for our food. One disease in particular, a parasitic infection of the intestine called coccidiosis, is particularly troubling because it is a world-wide problem. Even the lowest levels of infection rob animals of their potential to grow fast and healthy. Presently, there is great concern about the use of antimicrobial drugs to curb such infections. One potential strategy to control these parasitic infections, however, may come from a better understanding of how the chicken itself copes with the infection, limiting its duration and impact. Researchers at ARS in Beltsville, Maryland conducted an experiment that addressed what type of inflammation products were generated in intestinal cells in response to infection. In particular they looked at how two potent antimicrobial products made in cells, the nitrogen-derived nitric oxide and oxygen-derived superoxide anion, interact. The researchers measured the change in enzymes in intestinal cells that generate these two reactants as well as measured how these compounds altered proteins in cells. Analyzing tissue samples representing different days of infection, the researchers showed that the generation of these two reactants increased as early as one day after infection. More importantly, where intestinal cell proteins were damages by these reactants, they associated with damaging the parasite more. Further studies are now planned on how we can exploit this natural but still cell damaging reaction to control parasites but limit the effects on the chicken intestinal cells themselves, thus improving the health of chickens without the use of antimicrobial drugs.
Technical Abstract: Intracellular generation of nitric oxide (NO) and superoxide anion (SOA) can result in the formation of 3'-nitrotyrosine proteins (NTp). Nitrated proteins usually are associated with significant perturbation in protein function, apoptosis, and cell death. We undertook the present study to establish the temporal dynamics of NTp generation in the enterocytes (ETCs) of broiler chickens in response to infection with Eimeria acervulina. Duodenal tissue was harvested from nonionfected (NOI) and infected (INF) broilers on days 1, 3, 6, 7 and 10 post-infection (PI) and fixed, embedded, and sectioned for analysis by quantitative immunohistochemistry with antibodies specific to NTp and the enzyme xanthine oxidase (XO). The ETC pixel density characteristics of the respective biomarkers was obtained by quantitative image analysis of photomicrographs and captured areas of interest (AOIs) representative of ETCs. NTp and XO increases were evident in intestinal villi as early one day PI (P<0.05 v NI). The levels of NTp and XO were greatest in ETCs in contrast to infiltrating cells where no XO was evident. The increases in ETC NTp and XO (number of positive cells and pixel content/cell) occurred in a defined pattern, significant by location for day PI, initiating in the distal villus and progressing down into the crypts. Two NTp patterns were observed: a high level associated with ETCs harboring nitrated parasites and a low-level increase in ETCs not containing Eimeria but in proximity. These data suggest that although injurious to the responding ETCs, NTp responses may mediate some of the processes that limit the progress of this infection and gut XO may play a major role in generating this cellular reaction.