PTGER4 and inflammatory bowel disease: Given this, we explored the effect of the prostaglandin (PG) receptors PTGIR and PTGER4 associated with IBD [17], receptors of PG I2 and PG E2 respectively, on regulating the expression of CP in THP-1 cells and hiPSC-derived monocytes in order to elucidate the role of the PG pathway in IBD pathology.