Interestingly, studies showed an antagonistic regulation between Ang-1 and Ang-2, the two key ligands for Tie-2 receptor(known astheendothelial-specificreceptortyrosine kinase), and that they are involved in vascular formation and maturation (8,9).
MC-derived Ang-1 can promote the growth of plasmacytomas by stimulating neovascularization (13).
Primary antibodies against Ang-1, Ang-2, Tie-2, and [beta]-actin, as well as secondary antibodies against either rabbit or mouse IgG were purchased from Santa Cruz Biotechnology, Inc.
RNA (2 mg) was then reverse-transcribed into cDNA using the SuperScriptTM III First-Strand Synthesis System RT-PCR kit and was further amplified using SYBR Green RT-PCR with the following specific oligonucleotides: Ang-1 sense primer, 5'-CAG CAC AAA GGA CGC TGA TA-3' and antisense primer, 5'-ATA GCG CCT TCA GAA GTC CA3'; Ang-2 sense primer, 5'-GAT CTT GTC TTG GCC TCA GC-3' and antisense primer, 5'-ACG GCG TTA GAC ATG TAG GG-3'; Tie-2 sense primer, 5'-AGG GCC TAG AGC CAG AGA CT-3' and antisense primer, 5'-AAG GTC TTT AGG GGC TGG AA-3'; or [beta]-actin sense primer, 5'-CAC CCG CGA GTA CAA CCT TC-3' and antisense primer, 5'-CCC ATA CCC ACC ATC ACA CC-3'.
Primary antibodies against Ang-1 (1:200 dilution), Ang-2 (1:500 dilution), Tie-2 (1:500 dilution), and [beta]-actin (1:500 dilution) were added and incubated overnight at 4[degrees]C, followed by reacting with the appropriate secondary antibody (1:4000 dilution, goat anti-rabbit IgG, and goat anti-mouse IgG-HRP) for 2 h.
Ang-1 and its naturally occurring antagonist Ang-2 act via the Tie-2 receptor tyrosine kinase, which is broadly expressed in the endothelium of the adult vasculature and in a subset of hematopoietic stem cells.
Previous studies have documented that Ang-1 mediates vascular stability while Ang-2 induces vascular instability by overriding Ang-1 -mediated Tie-2 activation (25).
In cerebral malaria, the research showed ANG-1 and ANG-2 were deregulated, likely contributing to excessive activation of the endothelial cells and parasite obstruction of brain blood vessels, associated with cerebral malaria.
High levels of ANG-2 and low levels of ANG-1 were associated with the severity of disease; the levels recorded on admission to hospital predicted which children would subsequently die.
Furthermore, drugs or agents that block ANG-2 or enhance ANG-1 may have a therapeutic role in preventing or treating cerebral malaria.
University of Pennsylvania (Philadelphia, PA) has patented pharmaceutical compositions that comprise a pharmaceutically acceptable carrier and either a therapeutically effective amount of an ECM-binding fragment of Ang-1
protein that comprises specified sequences or a homologous peptide thereof and pharmaceutical compositions that comprise a pharmaceutically acceptable carrier and a vector comprising a nucleic acid molecule that comprises the nucleotide sequence that encodes an ECM-binding fragment of Ang-1
protein that comprises specified sequences or a homologous peptide thereof are disclosed.
Samples of the maternal caruncular (CAR) and fetal cotyledonary (COT) portions of the placenta were snap frozen and later analyzed for vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor- 1 (VEGFR-1), vascular endothelial growth factor receptor-2 (VEGFR-2), angiopoietin-1 (ANG-1
), angiopoietin-2 (ANG-2), receptor for both Ang-1
and Ang-2 Tie-2, fibroblast growth factor (FGF), endothelial nitric oxide synthase (eNOS), and soluble guanylate cyclase (sGC).