Adil Sabr Al-Ogaili(1), Samer Sadeq Hameed(2*) and Noor Noori(1)
1- Department of Medical Laboratory Techniques, Kut-Technical Institute, Middle Technical University, Baghdad, Iraq
2- Department of Pathology and Diseases of Poultry, College of Veterinary Medicine, University of Baghdad, Baghdad, Iraq
Background: NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) is a cytosolic sensor that detects many microbial pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). It works as a pro-inflammatory cytokine that is encoded in the NLRP3 gene. This protein is profoundly expressed in macrophage and other innate immune system cells and participates in the assembly of NLRP3 inflammasome. NLRP3 inflammasome activates Caspase-1, which in turn renders the inactive precursors of the pro-inflammatory cytokines, the IL-1β and the IL-18, into active forms. This cytokine may trigger many inflammatory responses and cell signaling pathways as well. Little is known about this cytokine in chicken, especially its role in vaccines or induced-immune responses.
Aim: In this article, we sought to determine the presence of this gene mRNA in selected organs of male and female commercial egg-type brown leghorn chicken. In addition, we sought to determine this gene potential expression in these organs upon stimulation.
Methods: Using real-time PCR (RT-PCR), first we tested the presence of the NLRP3 gene in the chicken. Second, the levels and the time course of NLRP3 gene expression have been tested after stimulation with bacterial lipopolysaccharide (LPS) 12hrs, 24hrs, and 48hrs post-inoculation (pi). One-hundred twenty, day-old males and females egg-type brown leghorn chickens were used for the study.
Results: Our results showed that the gene mRNA is actually present in chickens solely. Also, there were no significant differences in the density of the expression and the distribution of the expression of the NLRP3 between chicken male and female and among different organs. Upon stimulation with LPS administration, however, there were marked elevation in the gene expression rate in small intestine, large intestine, gizzard, liver, lung, spleen and Peyer’s patches 12hrs pi. This elevation continued to elevate 24hrs pi. However, the significance of expression was only recorded in the small intestine, large intestine, and with less significance, in Peyer’s patches and spleen. This elevation in expression has subsided and almost returned to normal within these organs 48hrs pi.
Conclusion: The results suggested that there were no significant differences in the NLRP3 gene expression between male and female. Upon stimulation, the course of the gene expression showed a time-dependent response. First, the dominance in the NLRP3 gene mRNA expression was in the small intestine and the gizzard. Similarly, but less profoundly, the large intestine, Peyer’s patches, and spleen expressed NLRP3 mRNA 12hrs and 24hrs pi with LPS. Secondary immune organs, lung, small intestine and large intestine have expressed the NLRP3 mRNA significantly 24hrs pi. All the levels have diminished and almost returned to normal 48hrs pi.
Keywords: Chickens, NLRP3, Gene expression, Pro-inflammatory cytokine.