Lipopolysaccharide regulates cysteine-rich intestinal protein, a zinc-finger protein, in immune cells and plasma

Abstract

Cysteine-rich intestinal protein (CRIP), a double zinc-finger LIM protein, is expressed in great abundance in the intestine We have found comparable levels of GRIP mRNA in peritoneal macrophages, peripheral blood mononuclear cells (PBMC), and lesser amounts in thymus and spleen. Because GRIP expression was high in immune cells, rats were challenged with lipopolysaccharide (LPS) to determine whether expression was altered during the acute-phase immune response. Immunocytochemistry showed that, in adherent mononuclear cells, GRIP protein was localized in the cytoplasm, GRIP mRNA levels increased over time after LPS injection in peritoneal macrophages, PBMC, spleen, and intestine, No changes in GRIP mRNA level were seen in either liver or thymus. In PBMC, the level of GRIP mRNA decreased before increasing later in the acute-phase immune response, GRIP protein was found in the plasma. Shortly after LPS administration plasma GRIP decreased, suggesting that GRIP was either passively diffused out of capillaries or was actively shunted into tissues to execute its function. Increased GRIP expression seen in response to LPS suggests that GRIP may play a role in immune cell activation or differentiation or in processes associated with cellular repair.