Angiogenic Oligosaccharides of Hyaluronan Induce Multiple Signaling Pathways Affecting Vascular Endothelial Cell Mitogenic and Wound Healing Responses

Abstract

Hyaluronan (HA) is a large nonsulfated glycosaminoglycan and an important regulator of angiogenesis, in particular, the growth and migration of vascular endothelial cells. We have identified some of the key intermediates responsible for induction of mitogenesis and wound recovery. Treatment of bovine aortic endothelial cells with oligosaccharides of hyaluronan (o-HA) resulted in rapid tyrosine phosphorylation and plasma membrane translocation of phospholipase C␥1 (PLC␥1). Cytoplasmic loading with inhibitory antibodies to PLC␥1, G␤, and G␣ i/o/t/z inhibited activation of extracellular-regulated kinase 1/2 (ERK1/2). Treatment with the G␣ i/o inhibitor, pertussis toxin, reduced o-HA-induced PLC␥1 tyrosine phosphorylation, protein kinase C (PKC) ␣ and ␤1/2 membrane translocation, ERK1/2 activation, mitogenesis, and wound recovery, suggesting a mechanism for o-HA-induced angiogenesis through Gproteins, PLC␥1, and PKC. In particular, we demonstrated a possible role for PKC␣ in mitogenesis and PKC␤1/2 in wound recovery. Using antisense oligonucleotides and the Ras farnesylation inhibitor FTI-277, we showed that o-HA-induced bovine aortic endothelial cell proliferation, wound recovery, and ERK1/2 activation were also partially dependent on Ras activation, and that o-HA-stimulated tyrosine phosphorylation of the adapter protein Shc, as well as its association with Sos1. Binding of Src to Shc was required for its activation and for Ras-dependent activation of ERK1/2, cell proliferation, and wound recovery. Neither Src nor Ras activation was inhibited by pertussis toxin, suggesting that their activation was independent of heterotrimeric G-proteins. However, the specific Src kinase inhibitor PP2 inhibited G␤ subunit co-precipitation with PLC␥1, suggesting a possible role for Src in activation of PLC␥1 and interaction between two distinct o-HA-induced signaling pathways.

Isoindolone derivative QSN-10c induces leukemic cell apoptosis and suppresses angiogenesis via PI3K/AKT signaling pathway inhibition

“…Fresh medium was added to the wells with or without DMSO (0.1%) or various concentrations of QSN-10c (50, 100, and 200 μmol/L) or thalidomide (100, 200 μmol/L), and the cells were incubated for 12 h. Images were obtained at the time of the wounding and at 12-h intervals thereafter using a phasecontrast microscope (Olympus, Tokyo; 100×magnification). Cell migration was quantified according to methods reported in the literature [23] . The lesion area in each field of view was measured using the data from time 0 (T 0 wound area), and the wound area was then converted to the mean % recovery (%R) using the following equation:…”

Three vertebrate hyaluronan synthases are expressed during mouse development in distinct spatial and temporal patterns

“…As a molecule that closely associates with cells and has the ability to bind to multiple extracellular proteins, HA is an effective support structure in the extracellular matrix, particularly in supporting tissues of vertebrates, including cartilage, skin, smooth muscle, and other connective tissues (Spicer and Tien, 2004). As a signaling molecule, HA is able to activate several pathways through binding of HA receptors such as CD44 and receptor for hyaluronanmediated motility (RHAMM; Bourguignon et al, 2000;Lee and Spicer, 2000;Lokeshwar and Selzer, 2000;Oliferenko et al, 2000;Slevin et al, 2002). There is recent evidence for a role of intracellular HA, possibly as a regulator of cell division (Evanko and Wight, 1999).…”

Defining the roles of T cell membrane proteinase and CD44 in type 1 diabetes

“…CD44 also interacts with the Rho-family GTPases and induces the rearrangement of the cytoskeleton. The binding of CD44 to hyaluronan stimulates the downstream signaling pathways and leads to the activation of PKCa (9). Antigenic stimulation of T cells induces the cell surface expression of the highly active form of CD44 which avidly and with high affinity, binds hyaluronan.…”