Lipid-binding proteins in rat and human kidney.
BACKGROUND
The kidney metabolizes actively lipophilic molecules. Several species of lipid-binding proteins (LBPs) have been well characterized, including fatty acid-binding proteins (FABPs), acyl-CoA binding protein (ACBP), sterol carrier protein 2 (SCP2), cellular retinol binding protein (CRBP), and phosphatidylinositol transfer protein (PITP).


METHODS
To clarify which LBPs are expressed in isolated rat glomeruli (RG), cultured rat mesangial cells (RMC) and human kidney, RT-PCR, immunoblot analysis and immunohistochemistry were performed.


RESULTS
Protein and mRNA expression of heart type (H-) FABP was found in RMC, but not in RG. Immunohistochemistry using antihuman H-FABP antibody revealed that an H-FABP like protein was present in the capillary wall and distal tubules of human glomeruli. Immunoblot analysis using the antibody showed that a 110-kDa protein related to H-FABP was present in human isolated glomeruli but not in any other tissues tested including blood, liver, and heart, and that the 14-kDa protein, H-FABP itself was localized in the distal tubules of human kidney. mRNA for SCP2, ACBP and PITP was detected in RG and RMC. CRBP and mRNA was detected in RG but not RMC.


CONCLUSIONS
A variety of lipid-binding proteins are present in rat glomeruli. In human glomeruli, a novel 110-kDa H-FABP-related protein is localized specifically in the capillary wall.
Department of Clinical and Laboratory Medicine, Faculty of Medicine, Fukui Medical University, Japan. hkimura@fmsrsa.fukui-med.ac.jp
H
H
Kimura
H
H
Fujii
S
S
Suzuki
T
T
Ono
M
M
Arakawa
F
F
Gejyo
D000818:Animals; D002352:Carrier Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000737:chemistry* / Q000166:cytology; D007678:Kidney Glomerulus / Q000737:chemistry / Q000166:cytology; D007684:Kidney Tubules / Q000737:chemistry / Q000166:cytology; D050356:Lipid Metabolism; D008297:Male; D018996:Myelin P2 Protein / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY; D014018:Tissue Distribution; D025521:Tumor Suppressor Proteins
D002352:Carrier Proteins; C107608:FABP7 protein, human; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D018996:Myelin P2 Protein; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins