Biology Reference
In-Depth Information
recipients of F344 allograft hearts were infected with RCMV, and graft and native
hearts were harvested at 21 and 28 days after transplantation (the critical time of
RCMV-accelerated TVS). The allograft hearts from three recipients (±RCMV)
were analyzed using the Affymetrix Rat Genome 230 2.0 arrays with probe sets for
30,000 individual transcripts. The gene expression was analyzed and fold changes
were calculated by comparing the native hearts to the infected or uninfected
allografts. As anticipated, we identified a number of cellular genes expressed in allo-
grafts (infected and uninfected) that were significantly up- or downregulated (more
than twofold) compared to native hearts. While comparing the infected vs uninfected
allografts, we found 385 cellular genes significantly deregulated (more than twofold)
at day 21 and 143 such genes at day 28. Interestingly, many of the upregulated genes
are involved in WH, including genes associated with tumor invasion, cytokines/
chemokines, cytoskeleton, signaling, adhesion, and ECM. Approximately 134 of the
upregulated genes are known mediators of AG/WH, including angiopoietin, cathep-
sins, chemokines, the CNN family, endothelin, ECM/BM components (laminin,
fibronectin, osteopontin, tenascin); the EGF family; hematopoietic growth factors,
the insulin growth factor binding protein (IGFBP) family, matrix metalloproteinases
(MMPs); platelet derived growth factor (PDGF); TGF-b; the tumor necrosis factor
receptor (TNFR) superfamily; urokinase-type plasminogen activator and receptor
(uPA/uPAR), and vascular endothelial growth factor (VEGF). Shown in Table 1 are
the average fold changes of the AG/WH genes from the infected or uninfected allo-
grafts compared to the average intensities of the native hearts. The most highly
induced genes are part of a signaling complex involved in ECM modification during
WH. Of these genes, MMP12 and osteopontin were upregulated at day 28 in the
infected allografts compared to uninfected allografts (367- and 395-fold vs 6- and
12-fold, respectively, compared to native hearts). Another set of key players of WH
is urokinase-type plasminogen activator (uPA) and receptor (uPAR), which were also
highly upregulated in infected allografts compared to uninfected (65- and 12-fold vs
nine- and threefold, respectively). In addition, MCP-1 and IL-1, which are potent
inducers of MMP12, osteopontin, and the uPA system, are highly represented in the
infected allografts. Overall, our findings support a hypothesis that RCMV infection
tips the balance of activator and inhibitory effectors that drive WH, the result of
which is acceleration of vascular disease.
In Vitro Models of HCMV-Mediated Wound Healing
and Angiogenesis
While
in vivo
animal models have provided solid evidence for the link between
CMV and the acceleration of vascular disease processes,
in vitro
models allow one
to explore underlying molecular and cellular mechanisms associated with this link.
Vascular tissue repair during allograft rejection involves the cellular processes of
migration, activation, proliferation, and differentiation, and these events occur in
multiple cell types including macrophages, EC, SMC, and fibroblasts.
In vivo
and
