Induction of Chicken Host Defense Peptides within Disease-Resistant and -Susceptible Lines

Abstract

Host defense peptides (HDPs) are multifunctional immune molecules that respond to bacterial and viral pathogens. In the present study, bone marrow-derived cells (BMCs) and chicken embryonic fibroblasts (CEFs) were cultured from a Leghorn line (Ghs6) and Fayoumi line (M15.2), which are inbred chicken lines relatively susceptible and resistant to various diseases, respectively. The cells were treated by lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (poly(I:C)) and, subsequently, mRNA expression of 20 chicken HDPs was analyzed before and after the stimulation. At homeostasis, many genes differed between the chicken lines, with the Fayoumi line having significantly higher expression (p < 0.05) than the Leghorn line: AvBD1, 2, 3, 4, 6, and 7 in BMCs; CATH1, CATH3, and GNLY in CEFs; and AvDB5, 8, 9, 10, 11, 12, 13 in both BMCs and CEFs. After LPS treatment, the expression of AvBD1, 2, 3, 4, 5, 9, 12, CATH1, and CATHB1 was significantly upregulated in BMCs, but no genes changed expression in CEFs. After poly(I:C) treatment, AvBD2, 11, 12, 13, CATHB1 and LEAP2 increased in both cell types; CATH2 only increased in BMCs; and AvBD3, 6, 9, 14, CATH1, CATH3, and GNLY only increased in CEFs. In addition, AvBD7, AvBD14, CATH1, CATH2, GNLY, and LEAP2 showed line-specific expression dependent upon cell type (BMC and CEF) and stimulant (LPS and poly(I:C)). The characterization of mRNA expression patterns of chicken HDPs in the present study suggests that their functions may be associated with multiple types of disease resistance in chickens.

Natural Cyclooxygenase-2 Inhibitors Synergize With Butyrate to Augment Chicken Host Defense Peptide Gene Expression

“…Although HDPs are an important part of the innate immunity, not all HDPs are increasingly transcribed and produced in response to infection or injury. In chicken HTC macrophages, a 3-h LPS treatment triggered a massive IL-1b induction, but AvBD9 gene expression was not altered, which is consistent with earlier reports that AvBD9 was unaffected in the vagina or Sertoli cells of chickens for up to 24 h following LPS treatment (56,57), although another report appeared to suggest that AvBD9 is upregulated by LPS in chicken bone marrowderived cells (58). The discrepancy is currently unknown, perhaps it is cell type-dependent.…”

Impact of sodium butyrate on stimulating of some host defense peptides and body performance in broiler vaccinated with different avian influenza (H9N2) vaccines

“…In contrast, its elevation in untreated (group C) is due to the presence of PAMPs as an immune enhancer in inactivated H9N2p vaccine (17). The constant level of AvBD-10 between groups in 2 intervals may be due to bacterial colonization in the intestine, which leads to an increase in the level of expression of beta-defensin and CATH genes in chickens as components of the innate immune system (18).…”

Chicken LEAP2 Level Substantially Changes with Feed Intake and May Be Regulated by CDX4 in Small Intestine

“…Chicken LEAP2 was first identified as an antibacterial peptide [ 26 , 50 ]. Numerous studies have reported the antibacterial effect of chicken LEAP2 on various bacteria or viruses [ 22 , 23 , 24 , 25 , 26 , 27 ]. In this study, we deemphasized the antibacterial peptide function of chicken LEAP2 and investigated its function as a feed-intake regulator.…”

“…LEAP2 has conserved peptide sequences in various animals [ 21 ]. However, chicken LEAP2 has been studied as an antibacterial peptide [ 22 , 23 , 24 , 25 , 26 , 27 ]. As the gastrointestinal system of birds is different from that of humans and rats, it is unclear whether avian LEAP2 acts as a hormone in response to changes in diet [ 17 ].…”