ELISA

Syndecan-4 (SDC4) is a protein that in humans is encoded by the SDC4 gene. The protein is found as a homodimer and is a member of the syndecan proteoglycan family. It is mapped to 20q13.12. Syndecan-4 is one of the four vertebrate syndecans and has a molecular weight of ~20 kDa. It is a transmembrane (type I) heparan sulfate proteoglycan that functions as a receptor in intracellular signaling. Syndecan-4 also regulates the actin cytoskeleton, cell adhesion, and cell migration. In addition, Syndecan-4 can activate protein kinase C (PKC). The variable domain of syndecan-4 could be a site of self-association. What’s more, Syndecan-4 also binds to phosphatidylinositol (4,5)-bisphosphate (PIP2) through the variable domain and increases PKC activity ten-fold.

Biglycan (BGN) is a small leucine-rich repeat proteoglycan (SLRP) which is found in a variety of extracellular matrix tissues, including bone, cartilage and tendon. It is an important structural component of articular cartilage and participates in the assembly of the chondrocyte extracellular matrix through formation of protein interactions with type VI collagen and large proteoglycan aggregates. In humans, Biglycan is encoded by the BGN gene. It is mapped to Xq28. Biglycan is believed to play a role in the mineralisation of bone, and its core protein binds to the growth factors BMP-4 and influences its bioactivity. It has been reported that the presence of biglycan is necessary for BMP-4 to exert its effects on osteoblasts. There is also evidence that biglycan can bind to TGF-beta 1. In addition, Biglycan plays an important role in cell signaling.

TFPI2, also called Tissue factor pathway inhibitor 2, is a protein that in humans is encoded by the TFPI2 gene. It is mapped to 7q21.3. This gene encodes a member of the Kunitz-type serine proteinase inhibitor family. The protein can inhibit a variety of serine proteases including factor VIIa/tissue factor, factor Xa, plasmin, trypsin, chymotryspin and plasma kallikrein. This gene has been identified as a tumor suppressor gene in several types of cancer. Qualitative PCR and microarray analyses showed that expression of TFPI2 was inversely correlated with that of MIR616 in prostate cancer cell lines, primary tumors of various grades, and normal tissue.

CEACAM1, also known as CD66a (Cluster of Differentiation 66a), is a human glycoprotein encoded by a gene. This gene encodes a member of the carcinoembryonic antigen (CEA) gene family, which belongs to the immunoglobulin superfamily. CEACAM1 is mapped to 19q13.2 in human. The encoded protein was originally described in bile ducts of liver as biliary glycoprotein. Subsequently, it was found to be a cell-cell adhesion molecule detected on leukocytes, epithelia, and endothelia. The encoded protein mediates cell adhesion via homophilic as well as heterophilic binding to other proteins of the subgroup. Multiple cellular activities have been attributed to the encoded protein, including roles in the differentiation and arrangement of tissue three-dimensional structure, angiogenesis, apoptosis, tumor suppression, metastasis, and the modulation of innate and adaptive immune responses.

Fibroblast growth factor 23 or FGF23 is a protein that in humans is encoded by the FGF23 gene. It is a member of the fibroblast growth factor (FGF) family which is responsible for phosphate metabolism. The main function of FGF23 seems to be regulation of phosphate concentration in plasma. FGF23 is secreted by Osteocytes in response to elevated Calcitriol. And it acts on the kidneys, where it decreases the expression of NPT2, a sodium-phosphate cotransporter in the proximal tubule. Thus, FGF23 decreases the reabsorption and increases excretion of phosphate. Also, FGF23 may suppress 1-alpha-hydroxylase, reducing its ability to activate vitamin D and subsequently impairing calcium absorption.

Interleukin 37(IL-37) also named IL1F7, is a protein that in humans is encoded by the IL1F7 gene. The protein encoded by this gene is a member of the interleukin 1 cytokine family. And it is mapped to 2q13. In vitro expression analysis showed that IL-37 was a secretory protein. And IL-37 could play an important role in the link between innate and adaptive immunity and may be useful for tumor immunotherapy. Meanwhile, IL-37 inhibits the production of inflammatory cytokines in peripheral blood mononuclear cells of patients with systemic lupus erythematosus. In addition, IL-37 can emerged as a dual-function cytokine with intra- and extracellular properties for suppressing innate inflammation. Furthermore, IL-37 is a new anti-inflammatory cytokine that plays an important role in protecting against tissue injury during infections via limiting immune and inflammatory reactions.

Chemokine (C-X-C motif) ligand 3 (CXCL3) is a small cytokine belonging to the CXC chemokine family. It is mapped to 14p2 in rat. CXCL3 controls migration and adhesion of monocytes and mediates its effects on its target cell by interacting with a cell surface chemokine receptor. It has been shown that CXCL3 regulates cell autonomously the migration of the precursors of cerebellar granule neurons toward the internal layers of cerebellum, during the morphogenesis of cerebellum. CXCL3 also play fundamental roles in the development, homeostasis and it has effects on cells of the central nervous system as well as on endothelial cells involved in angiogenesis or angiostasis.

Interleukin-34, or IL-34 is a protein belonging to a group of cytokines called interleukins. It is mapped to 16q22.1. The discovery of IL-34 protein in the red pulp of the spleen suggests involvement in growth and development of myeloid cells, consistent with its activity on monocytes. IL-34 is a recently discovered cytokine that acts on tissue resident macrophages and Langerhans cells upon binding the receptor for CSF-1, CSF-1R. It also can promote the differentiation and viability of monocytes and macrophages through the colony-stimulating factor-1 receptor. In addition, it promotes the development, survival, and function of microglia and Langerhans cells, therefore, this cytokine may predominately function in brain and skin biology.

Interleukin-34, or IL-34 is a protein belonging to a group of cytokines called interleukins. It is mapped to 16q22.1. The discovery of IL-34 protein in the red pulp of the spleen suggests involvement in growth and development of myeloid cells, consistent with its activity on monocytes. IL-34 is a recently discovered cytokine that acts on tissue resident macrophages and Langerhans cells upon binding the receptor for CSF-1, CSF-1R. It also can promote the differentiation and viability of monocytes and macrophages through the colony-stimulating factor-1 receptor. In addition, it promotes the development, survival, and function of microglia and Langerhans cells, therefore, this cytokine may predominately function in brain and skin biology.