Renal Macrophage Migration and Crystal Phagocytosis via Inflammatory-Related Gene Expression During Kidney Stone Formation and Elimination in Mice: Detection by Association Analysis of Stone-Related Gene Expression and Microstructural Observation

Mice have a strong ability to eliminate renal calcium oxalate crystals, and our previous examination indicated a susceptibility in which monocyte-macrophage interaction could participate in the phenomenon To clarify the macrophage-related factors playing roles in the prevention of crystal formation in mouse kidneys, morphologic and expression studies based on microarray pathway analysis were performed Eight-week-old male C57BL/6N mice were administered 80 mg/kg of glyoxylate by daily intraabdominal injection for 15 days, and the kidneys were extracted every 3 days for DNA microarray analysis Based on the raw data of microarray analysis, pathway analyses of inflammatory response demonstrated macrophage activation through the increased expression of chemokine (C-X-C) ligand 1, fibronectin 1, and major histocompatability (MHC) class II Association analysis of related gene expression values by quantitative reverse transcription polymerase chain reaction (RT-PCR) indicated the high association of chemokine (C-C) ligand 2, CD44, colony-stimulating factor 1, fibronectin 1, matrix gla protein, secreted phosphoprotein 1, and transforming growth factor beta 1 (TGF-beta 1) with the amount of both renal crystals and F4/80, a macrophage marker Immunohistochemically, interstitial macrophages increased during the experimental course, and CD44 and MHC class II were upregulated around crystal-formation sites Ultrastructural observation of renal macrophages by transmission electron microscopy indicated interstitial macrophage migration with the phagocytosis of crystals In conclusion, increased expression of inflammation-related genes of renal tubular cells induced by crystal formation and deposition could induce monocyte-macrophage migration and phagocytosis via the interaction of CD44 with osteopontin and fibronectin Such crystal-removing ability of macrophages through phagocytosis and digestion might become a new target for the prevention of stone formation (C) 2010 American Society for Bone and Mineral Research