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Supplier: STEMCELL Technologies

The platelet-derived growth factor (PDGF) family has five heparin-binding members that assemble into four homodimers (PDGF-AA, PDGF-BB, PDGF-CC, and PDGF-DD) and one heterodimer (PDGF-AB; Fretto et al.; Li and Eriksson). PDGF signals through the receptor tyrosine kinases PDGFRα and PDGFRβ. It has been shown that PDGF-induced migration involves signaling pathways involving MEK/ERK, EGFR, Src, and PI3K/AKT (Kim et al.). PDGF is a potent mitogen for cells of mesenchymal origin, such as fibroblasts, glial cells, and vascular smooth muscle cells. PDGF has been implicated in pathogenesis of atherosclerosis, glomerulonephritis, cancer, and in the contraction of vascular smooth muscle cells of rat aortic tissues (Fretto et al.; Sachinidis et al.). PDGF-DD promotes growth and survival of renal artery smooth muscle cells and lens epithelial cells, and can act as a macrophage chemoattractant (Changsirikulchai et al.; Lokker et al.; Ray et al.; Uutela et al.).

Supplier: STEMCELL Technologies

Vascular endothelial growth factor (VEGF) is a heparin-binding homodimeric glycoprotein involved in vasculogenesis and angiogenesis. VEGF binds to FLT1 (VEGFR-1) and KDR (VEGFR-2), and activates Raf/MEK/ERK and PI3K/AKT pathways (Ferrara et al.). VEGF exists in multiple isoforms that result from alternative splicing of VEGF mRNA in the terminal exon. Proximal splice-site selection in exon 8 results in pro-angiogenic VEGFxxx isoforms (xxx is the number of amino acids), whereas distal splice-site selection results in anti-angiogenic VEGFxxxb isoforms (Nowak et al.). VEGF plays an important role in neurogenesis both in vitro and in vivo (Storkebaum et al.). It has neurotrophic effects on neurons of the central nervous system, and it promotes growth and survival of dopaminergic neurons and astrocytes. VEGF also promotes growth and survival of vascular endothelial cells, monocyte chemotaxis, and colony formation by granulocyte-macrophage progenitor cells (Ferrara et al.). Various splice variants of VEGF exist, with different functions. For example, it has been shown that VEGF isoform VEGF-164(165) and not VEGF-120(121) induces inflammation, stimulates intracellular adhesion molecule (ICAM)-1 expression on endothelial cells, and induces chemotaxis of monocytes (Usui et al.).

Supplier: STEMCELL Technologies

Stem cell factor (SCF) is an early-acting cytokine that plays a pivotal role in the regulation of embryonic and adult hematopoiesis. SCF promotes cell survival, proliferation, differentiation, adhesion, and functional activation of cells at multiple levels of the hematopoietic hierarchy. Together with other cytokines such as thrombopoietin and Flt3/Flk-2 Ligand, SCF is commonly used to promote expansion of primitive hematopoietic stem cells and multi-potent progenitor cells in culture (Martin et al.; Kent et al.). In synergy with various growth factors, including IL-2, IL-3, IL-6, IL-7, G-CSF, and erythropoietin, SCF increases proliferation and differentiation of myeloid and erythroid progenitor cells and a subset of lymphoid progenitor cells (Broudy). SCF is also a primary growth and activation factor for mast cells and eosinophils. SCF exists in two biologically active splice forms: a soluble and a transmembrane isoform. Upon binding to its receptor (c-Kit tyrosine kinase receptor; CD117), it activates PI3K, JAK/STAT, and MAPK pathways. SCF and signaling from c-Kit have also been reported to play an important role in pigmentation, fertility, vasculogenesis, motility of the gut via c-Kit positive interstitial cells of Cajal, and in the migration of neuronal stem and progenitor cells to sites of injury in the brain. This product is animal component-free.

Supplier: STEMCELL Technologies

Interleukin-8 (IL-8) is a member of the CXC subfamily of chemokines and is produced by leukocytic cells (monocytes, T cells, neutrophils, and natural killer cells) and non-leukocytic somatic cells (endothelial cells, fibroblasts, and epithelial cells), with the most prominent source being monocytes and macrophages. Its production is induced by inflammatory stimuli, such as IL-1. IL-8, also known as CXCL8, activates neutrophils inducing chemotaxis, exocytosis, and the respiratory burst (Baggiolini and Clark-Lewis; Mukaida). IL-8 is considered one of the most potent neutrophil chemoattractants in inflammation and binds to two different chemokine receptors on leukocytes: the G protein-coupled receptors CXCR1 and CXCR2 (Hoffmann et al.; de Oliveira et al.). IL-8 has angiogenic effects on human intestinal microvascular endothelial cells in vitro that are mediated by CXCR2 (Heidemann et al.). IL-8 is reported to promote breast cancer progression by increasing cell invasion, angiogenesis, and metastasis and has been reported to be involved in regulating breast cancer stem-like cells (Singh et al.). IL-8 also has proangiogenic properties in inflammatory diseases of the conjunctiva, cornea, iris, retina, and orbit (Ghasemi et al.). It was also shown that a major T cell effector function in human newborns is IL-8 production, which has the potential to activate antimicrobial neutrophils and gamma/delta T cells (Gibbons et al.). A variety of human pathogens, such as HIV and Mycobacterium tuberculosis, have been shown to induce IL-8 production by monocytes and macrophages (Friedland et al.; Meddows-Taylor et al.).

Supplier: STEMCELL Technologies

Platelet-derived growth factor (PDGF) is a dimeric glycoprotein consisting of two disulfide bridge-stabilized polypeptide chains, A and B, which are assembled as heterodimers (PDGF-AB) or homodimers (PDGF-AA and PDGF-BB) (Fretto et al.; Westermark and Heldin). PDGF signals through the receptor tyrosine kinases PDGFRalpha and PDGFRbeta. It has been shown that PDGF-induced migration involves signaling pathways involving MEK/ERK, EGFR, Src, and PI3K/AKT (Kim et al.). PDGF is a potent mitogen for cells of mesenchymal origin, such as fibroblasts, glial cells, and vascular smooth muscle cells. PDGF has been implicated in pathogenesis of atherosclerosis, glomerulonephritis, cancer, and in the contraction of vascular smooth muscle cells of rat aortic tissues (Fretto et al.; Sachinidis et al.). It has been suggested that PDGF-AA is an important autocrine regulator of vascular endothelial growth factor (VEGF) expression in non-small cell lung carcinomas (Shikada et al.). PDGF-AA also mediates proliferation of oligodendrocyte progenitor cells and oligodendrocyte lineage differentiation through the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) (Hu et al.). PDGF-AA is commonly used to differentiate human pluripotent stem cell (hPSC)-derived neural progenitor cells into oligodendrocyte precursor cells (Piao et al.).