Progranulin is a 68.5 kDa protein consisting of 593 amino acids (inclusive Signal peptide), which is present in vivo in a strongly glycosylated form and therefore has a size of approximately 90 kDa. Progranulin has seven conserved domains, which are separated by linker sequences. Large (6-25 kDa) fragments called Granulines or Epithelines are produced by proteolytic cleavage catalyzed by serine proteases ( e.g. elastase).
Progranulin mRNA is expressed in many epithelial cells both in vitro and in vivo. He and Bateman proposed that the rate of growth of some epithelia is proportional to the level of intrinsic progranulin gene expression, and that elevated progranulin gene expression confers a transformed phenotype on epithelial cells including anchorage independence in vitro and growth as tumors in nude mice (2). They also found that progranulin mRNA is expressed in the inflammatory infiltrate in murine transcutaneous puncture wounds, and is highly induced in dermal fibroblasts and endothelia following injury. When applied to a cutaneous wound, progranulin increased the accumulation of neutrophils, macrophages, blood vessels, and fibroblasts in the wound. It acted directly on isolated dermal fibroblasts and endothelial cells to promote division, migration, and the formation of capillary-like tubule structures, concluding that progranulin is, therefore, probably a wound-related growth factor (3). Due to its tumor-promoting activity and multiple functions on hematopoietic cells and endotheial cells, progranulin may be a novel marker for oncology and hematology.
Sandwich type ELISA
PGRN, Granulin Epithelin Precursor, Proepithelin, PEPI, Acrogranin, Glycoprotein of 88 Kda, GP88, Glycoprotein 88, PC cell-derived growth factor, PCDGF
Principle of Method
This assay is a sandwich Enzyme Linked-Immunosorbent Assay (ELISA) for quantitative determination of human progranulin in biological fluids. A polyclonal antibody specific for progranulin has been precoated onto the 96-well microtiter plate. Standards and samples are pipetted into the wells for binding to the coated antibody. After extensive washing to remove unbound compounds, progranulin is recognized by the addition of a biotinylated polyclonal antibody specific for progranulin (Detection Antibody). After removal of excess biotinylated antibody, HRP labeled streptavidin (STREP-HRP) is added. Following a final washing, peroxidase activity is quantified using the substrate 3,3’,5,5’-tetramethylbenzidine (TMB). The intensity of the color reaction is measured at 450 nm after acidification and is directly proportional to the concentration of progranulin in the samples.
Serum, Plasma, Urine, CSF, or Cell Culture Supernatant
This ELISA is specific for the measurement of natural and recombinant human progranulin. It does not cross-react with human RBP4, human adiponectin, human Nampt, human leptin, human RELM-β, human ANGPTL6, human FABP4, human TNF-α, human IL-33, human GPX3, human resistin, human clusterin, human vaspin, human PAl1, human ANGPTL3, mouse Nampt, rat Nampt.
Serum and Plasma : 0.5 µL (actual amount of sample loaded in well after dilution)
Urine: 5 µL (actual amount of sample loaded in well after dilution)
CSF: 25 µL (actual amount of sample loaded in well after dilution)
Calibration Range: 0.063 ng/ml – 4 ng/ml
Limit of Detection
Intra-assay (Within-Run) C.V.
Inter-assay (Run-to-Run) C.V.
References to Summary
- Isolation and sequence of the granulin precursor cDNA from human bone marrow reveals tandem cysteine-rich granulin domains: V. Bhandari, et al.; Nat. Acad. Sci. 89, 1715 (1992)
- Progranulin gene expression regulates epithelial cell growth and promotes tumor growth in vivo: He, et al.; Cancer Res. 59, 3222 (1999)
- Progranulin is a mediator of the wound response: Z. He, et al.; Nature Med. 9, 225 (2003)