Peptidoglycan Recognition Proteins Are Differentially Regulated by Time and Long‐Chain Polyunsaturated Fatty Acids In Neonatal Pig Intestinal Epithelial Cells, IPECJ2

Abstract

Peptidoglycan recognition proteins (PGlyRP) are a family of highly conserved pattern recognition receptors of the innate immune system. PGlyRP1, 3, and 4 have direct bactericidal activity, while PGlyRP2 is bound and secreted from cells and hydrolyzes peptidoglycan through amidase activity. PGlyRP3 is expressed in human colon‐like CaCO‐2 cells and is known to enhance anti‐inflammatory responses post‐bacterial challenge. This study hypothesized that PGlyRP expression in IPECJ2 cells would be regulated by time post‐confluence and by long chain polyunsaturated fatty acid (LC‐PUFA) treatment. IPECJ2 cells were grown to confluence and mRNA abundance was measured by RT‐PCR. PGlyRP 2 and 4 were expressed in IPECJ2 cells and differentially regulated over time (P < 0.001). PGlyRP2 mRNA abundance decreased over 16d (P < 0.001), whereas PGlyRP4 mRNA abundance increased over time. In addition, LC‐PUFA (n‐3 and n‐6) dose‐dependently increased expression of PGlyRP2 mRNA by 100‐175% within 24h compared to vehicle‐treated cells (P< 0.05). PGlyRP4 mRNA increased 65 % when treated with 100 μM eicosapentaenoic acid (n‐3) compared to vehicle treated cells (P<0.05). In conclusion, IPECJ2 cells express PGlyRP2 and 4, have differential patterns of expression over time post‐confluence and are acutely regulated by LC‐PUFA. These data implicate a potential mechanism for dietary LC‐PUFA to modulate intestinal health by altering mucosal signaling mechanisms between luminal microbiotia, enterocytes and the mucosal immune system. Funded by Undergraduate Research Grant.