Page 275 - 2014 Printable Abstract Book
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irradiations ( Cs) at doses of 0.1 or 1 Gy, in order to evaluate the importance of radiation quality and
dose rate for EMT. Particularlty we investigated the role of the TGF-β signaling in the EMT induction. The
evaluated markers were epithelial (E-cadherin) and mesenchymal (fibronectin and vimentin). Initial
results showed no induction of EMT with acute α- and γ- irradiation in any of the cell lines. On the other
hand chronic exposure to same doses in combination with TGF-β showed trend in enhanced EMT. In co-
culture systems of stromal fibroblasts and epithelial cells exposed to protracted irradiation there was not
only induction of EMT in the irradiated cells, but also dose-dependency of effect. In the fibroblasts there
was increase in the myofibroblast marker α-SMA post irradiation. This molecule has been previously
connected with increased motility of fibroblast cells associated with tumors. In the case of co-cultures,
there has also been detected additive effect of protracted low LET radiation and TGF-β in induction of
EMT in the epithelial cells. Therefore, we suggest that very important role in the early stages of
carcinogenesis is played by the stromal cells and signaling changes in them are one of main factors that
induce EMT in the epithelial cells. Furthermore we are planning to study in details the dose rate-effects
and to apply co-culturing systems in 3D to evaluate the role of stromal cells in signaling.
(PS4-69) Radiation-induced changes in pulmonary macrophage subsets. Angela M. Groves, PhD; Carl
Johnston, PhD; Ravi Misra, PhD; Tyler Beach; Jacqueline Williams, PhD; and Jacob Finkelstein, PhD,
University of Rochester, Rochester, NY
One long term complication of exposure to radiation is the development of pulmonary fibrosis.
Responding to microenvironmental signals, macrophages become phenotypically polarized to orchestrate
inflammatory responses. Alternatively activated macrophages may contribute to the development of
fibrosis in the lung. The role of these cells in radiation induced pulmonary fibrosis was investigated.
Fibrosis prone C57 or pneumonitis prone C3H mice were exposed to 0 or 12.5 Gy whole lung irradiation
and lung digests were collected at various time points following exposure. CD45+ leukocytes were
characterized by flow cytometry. Alveolar macrophages (AM’s, CD11b low, CD11c+), interstitial
macrophages (IM’s, CD11b+, CD11c+), and immature macrophages (CD11b+, CD11c-) were indentified.
Expression of F4/80, present on mature macrophages, Ly6C, expressed by pro-inflammatory monocytes,
and mannose receptor (CD206), an alternative activation marker, were assessed in each population. Lung
irradiation results in a decrease in macrophages at early time points. Identification of discrete macrophage
populations showed that in C57 mice, radiation decreased the percentage of both AM's and IM's through
8 wk. In C3H mice, whereas radiation transiently decreased the percentage of AM's at 3 wk, the
percentage of IM's increased, remaining elevated through 8wk. In irradiated C57 mice, numbers of
immature macrophages increased at 8 wk, however within this population the percentage of Ly6C high
cells decreased. Radiation decreased the percentage of F4/80 high AM’s in C57 and C3H mice, by 3 wk.
These cells returned to control proportions by 8 wk in C3H but not C57 mice. Radiation decreased the
percentage of CD206+ AM's, but increased the percentage of CD206+ IM's by 3 wk. By 8 wk CD206+ AMs
and IM's from C57 mice increased, while in C3H mice CD206+ AM's were at 0 Gy levels, though IM's
remained elevated. These results demonstrate cell specific modulation of macrophage subsets following
irradiation. Post-depletion, increased AM expression of the alternative activation marker, mannose
receptor in fibrosis prone C57 mice but not in pneumonitis prone C3H mice suggests a role for these cells
in radiation induced fibrogenesis. Funded By: R01 AI101732-01, U19AI091036, P30 ES-01247 and ES T32
07026
273 | P a g e
irradiations ( Cs) at doses of 0.1 or 1 Gy, in order to evaluate the importance of radiation quality and
dose rate for EMT. Particularlty we investigated the role of the TGF-β signaling in the EMT induction. The
evaluated markers were epithelial (E-cadherin) and mesenchymal (fibronectin and vimentin). Initial
results showed no induction of EMT with acute α- and γ- irradiation in any of the cell lines. On the other
hand chronic exposure to same doses in combination with TGF-β showed trend in enhanced EMT. In co-
culture systems of stromal fibroblasts and epithelial cells exposed to protracted irradiation there was not
only induction of EMT in the irradiated cells, but also dose-dependency of effect. In the fibroblasts there
was increase in the myofibroblast marker α-SMA post irradiation. This molecule has been previously
connected with increased motility of fibroblast cells associated with tumors. In the case of co-cultures,
there has also been detected additive effect of protracted low LET radiation and TGF-β in induction of
EMT in the epithelial cells. Therefore, we suggest that very important role in the early stages of
carcinogenesis is played by the stromal cells and signaling changes in them are one of main factors that
induce EMT in the epithelial cells. Furthermore we are planning to study in details the dose rate-effects
and to apply co-culturing systems in 3D to evaluate the role of stromal cells in signaling.
(PS4-69) Radiation-induced changes in pulmonary macrophage subsets. Angela M. Groves, PhD; Carl
Johnston, PhD; Ravi Misra, PhD; Tyler Beach; Jacqueline Williams, PhD; and Jacob Finkelstein, PhD,
University of Rochester, Rochester, NY
One long term complication of exposure to radiation is the development of pulmonary fibrosis.
Responding to microenvironmental signals, macrophages become phenotypically polarized to orchestrate
inflammatory responses. Alternatively activated macrophages may contribute to the development of
fibrosis in the lung. The role of these cells in radiation induced pulmonary fibrosis was investigated.
Fibrosis prone C57 or pneumonitis prone C3H mice were exposed to 0 or 12.5 Gy whole lung irradiation
and lung digests were collected at various time points following exposure. CD45+ leukocytes were
characterized by flow cytometry. Alveolar macrophages (AM’s, CD11b low, CD11c+), interstitial
macrophages (IM’s, CD11b+, CD11c+), and immature macrophages (CD11b+, CD11c-) were indentified.
Expression of F4/80, present on mature macrophages, Ly6C, expressed by pro-inflammatory monocytes,
and mannose receptor (CD206), an alternative activation marker, were assessed in each population. Lung
irradiation results in a decrease in macrophages at early time points. Identification of discrete macrophage
populations showed that in C57 mice, radiation decreased the percentage of both AM's and IM's through
8 wk. In C3H mice, whereas radiation transiently decreased the percentage of AM's at 3 wk, the
percentage of IM's increased, remaining elevated through 8wk. In irradiated C57 mice, numbers of
immature macrophages increased at 8 wk, however within this population the percentage of Ly6C high
cells decreased. Radiation decreased the percentage of F4/80 high AM’s in C57 and C3H mice, by 3 wk.
These cells returned to control proportions by 8 wk in C3H but not C57 mice. Radiation decreased the
percentage of CD206+ AM's, but increased the percentage of CD206+ IM's by 3 wk. By 8 wk CD206+ AMs
and IM's from C57 mice increased, while in C3H mice CD206+ AM's were at 0 Gy levels, though IM's
remained elevated. These results demonstrate cell specific modulation of macrophage subsets following
irradiation. Post-depletion, increased AM expression of the alternative activation marker, mannose
receptor in fibrosis prone C57 mice but not in pneumonitis prone C3H mice suggests a role for these cells
in radiation induced fibrogenesis. Funded By: R01 AI101732-01, U19AI091036, P30 ES-01247 and ES T32
07026
273 | P a g e
