Biology Reference
In-Depth Information
Table 2
(continued)
Induced or repressed factors
Most abundant factors in
HCMV-
HCMV secretome
Mock
infected
Fold
Average
Protein
average
average
change
Protein
intensity
ICAM-3
331±183
123±8
0.4
IP-10
975
IL-1R II
3387±570
1210±374*
0.4
IL-2 alpha
341±159
112±19
0.3
VEGF-D
374±188
119±21
0.3
IL-2 R alpha
3287±635
1029±392*
0.3
HCC-4
14014±11353
3193±1191
0.2
HGF
13954±11376
3174±1194
0.2
for detection was set at an average intensity of 500. Of these 144 proteins detected,
41 factors were significantly induced over the mock-infected secretome (Table 2).
The 35 most predominant proteins detected in the HCMV secretome are listed in
Table 2. The most highly abundant cellular factors present in the HCMV secretome
that contribute to WH/AG include the cytokines/chemokines (IL-6, osteoprotegerin,
GRO, CCL3, CCL5, CCL7, CCL20, CXCL-5, and CXCL-16), receptors (TNF-RI
and II and ICAM-1), growth factors (TGF-
1 and HGF), ECM modifiers (MMP-1,
TIMP-1, TIMP-2, TIMP-4), and the angiogenic RNase angiogenin. Interestingly,
MCP-3 was induced over 85-fold in the HCMV secretome compared to the mock
secretome. Most of the highly induced proteins detected in our assay (HCMV vs
mock) included chemokines such as CCL1, CCL3, CCL4, CCL5, CCL20, CXCL10,
CXCL11). Interestingly, many of the genes that were identified by microarray anal-
ysis in the rat allograft hearts were also found in the HCMV secretome, suggesting
that the factors involved in HCMV-induced angiogenesis and wound healing are
similar to those expressed in the RCMV-infected allografts and importantly, that
these in vitro and in vivo processes are parallel to each other.
β
HCMV Secretome Induces Angiogenesis in Endothelial Cells
Angiogenesis leading to vessel formation in vivo consists of a growth phase fol-
lowed by a stabilization phase (Auerbach et al. 2003; Guidolin et al. 2004). Growth
phase events include proteolytic digestion of the basement membrane (BM) and
extracellular matrix (ECM) of the existing vessel, migration and proliferation of
ECs, lumen formation within the EC sprout, and anastomosis of sprouts to form
neovessels. Stabilization involves arrest of EC proliferation, EC differentiation,
intercellular adhesion and remodeling of the BM/ECM network to create an imma-
ture capillary. Key steps in both phases of angiogenesis can be modeled using an in
vitro assay: the matrigel assay for capillary-like tubule formation (Wegener et al.
2000; Xiao et al. 2002). The extent of tubule formation and stabilization depends
