Identification of miRNA signatures associated with radiation-induced late lung injury in mice.

Acute radiation exposure of the thorax can lead to late serious, and even life-threatening, pulmonary and cardiac damage. Sporadic in nature, late complications tend to be difficult to predict, which prompted this investigation into identifying non-invasive, tissue-specific biomarkers for the early detection of late radiation injury. Levels of circulating microRNA (miRNA) were measured in C3H and C57Bl/6 mice after whole thorax irradiation at doses yielding approximately 70% mortality in 120 or 180 days, respectively (LD70/120 or 180). Within the first two weeks after exposure, weight gain slowed compared to sham treated mice along with a temporary drop in white blood cell counts. 52% of C3H (33 of 64) and 72% of C57Bl/6 (46 of 64) irradiated mice died due to late radiation injury. Lung and heart damage, as assessed by computed tomography (CT) and histology at 150 (C3H mice) and 180 (C57Bl/6 mice) days, correlated well with the appearance of a local, miRNA signature in the lung and heart tissue of irradiated animals, consistent with inherent differences in the C3H and C57Bl/6 strains in their propensity for developing radiation-induced pneumonitis or fibrosis, respectively. Radiation-induced changes in the circulating miRNA profile were most prominent within the first 30 days after exposure and included miRNA known to regulate inflammation and fibrosis. Importantly, early changes in plasma miRNA expression predicted survival with reasonable accuracy (88-92%). The miRNA signature that predicted survival in C3H mice, including miR-34a-5p, -100-5p, and -150-5p, were associated with pro-inflammatory NF-κB-mediated signaling pathways, whereas the signature identified in C57Bl/6 mice (miR-34b-3p, -96-5p, and -802-5p) was associated with TGF-β/SMAD signaling. This study supports the hypothesis that plasma miRNA profiles could be used to identify individuals at high risk of organ-specific late radiation damage, with applications for radiation oncology clinical practice or in the context of a radiological incident

Adaptation of the Tumor Antigen Presentation Machinery to Ionizing Radiation.

Ionizing radiation (IR) can reprogram proteasome structure and function in cells and tissues. In this article, we show that IR can promote immunoproteasome synthesis with important implications for Ag processing and presentation and tumor immunity. Irradiation of a murine fibrosarcoma (FSA) induced dose-dependent de novo biosynthesis of the immunoproteasome subunits LMP7, LMP2, and Mecl-1, in concert with other changes in the Ag-presentation machinery (APM) essential for CD8+ T cell-mediated immunity, including enhanced expression of MHC class I (MHC-I), β2-microglobulin, transporters associated with Ag processing molecules, and their key transcriptional activator NOD-like receptor family CARD domain containing 5. In contrast, in another less immunogenic, murine fibrosarcoma (NFSA), LMP7 transcripts and expression of components of the immunoproteasome and the APM were muted after IR, which affected MHC-I expression and CD8+ T lymphocyte infiltration into NFSA tumors in vivo. Introduction of LMP7 into NFSA largely corrected these deficiencies, enhancing MHC-I expression and in vivo tumor immunogenicity. The immune adaptation in response to IR mirrored many aspects of the response to IFN-γ in coordinating the transcriptional MHC-I program, albeit with notable differences. Further investigations showed divergent upstream pathways in that, unlike IFN-γ, IR failed to activate STAT-1 in either FSA or NFSA cells while heavily relying on NF-κB activation. The IR-induced shift toward immunoproteasome production within a tumor indicates that proteasomal reprogramming is part of an integrated and dynamic tumor-host response that is specific to the stressor and the tumor and therefore is of clinical relevance for radiation oncology

Biology, History, and Control of Small Hive Beetle, Aethina tumida Murray

(Statement of Responsibility) by Josephine Ratikan(Thesis) Thesis (B.A.) -- New College of Florida, 2006(Electronic Access) RESTRICTED TO NCF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE(Bibliography) Includes bibliographical references.(Source of Description) This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.(Local) Faculty Sponsor: McCord, Elzi

Cellular autofluorescence following ionizing radiation.

Cells often autofluoresce in response to UV radiation excitation and this can reflect critical aspects of cellular metabolism. Here we report that many different human and murine cell types respond to ionizing radiation with a striking rise in autofluorescence that is dependent on dose and time. There was a highly reproducible fluorescent shift at various wavelengths, which was mirrored by an equally reproducible rise in the vital intracellular metabolic co-factors FAD and NADH. It appears that mitochondria, metabolism and Ca(2+) homeostasis are important for this to occur as cells without mitochondria or cells unable to alter calcium levels did not behave in this way. We believe these radiation-induced changes are of biological importance and that autofluorescence may even provide us with a tool to monitor radiation responses in the clinic

Regulatory T cells in radiotherapeutic responses

Radiation therapy (RT) can extend its influence in cancer therapy beyond what can be attributed to in-field cytotoxicity by modulating the immune system. While complex, these systemic effects can help tip the therapeutic balance in favor of treatment success or failure. Engagement of the immune system is generally through recognition of damage-associated molecules expressed or released as a result of tumor and normal tissue radiation damage. This system has evolved to discriminate pathological from physiological forms of cell death by signaling danger. The multiple mechanisms that can be evoked include a shift towards a pro-inflammatory, pro-oxidant microenvironment that can promote maturation of dendritic cells and, in cancer treatment, the development of effector T cell responses to tumor-associated antigens. Control over these processes is exerted by regulatory T cells (Tregs), suppressor macrophages and immunosuppressive cytokines that act in consort to maintain tolerance to self, limit tissue damage, and re-establish tissue homeostasis. Unfortunately, by the time RT for cancer is initiated the tumor-host relationship has already been sculpted in favor of tumor growth and against immune-mediated mechanisms for tumor regression. Reversing this situation is a major challenge. However, recent data show that removal of Tregs can tip the balance in favor of the generation of radiation-induced anti-tumor immunity. The clinical challenge is to do so without excessive depletion that might precipitate serious autoimmune reactions and increase the likelihood of normal tissue complications. The selective modulation of Treg biology to maintain immune tolerance and control of normal tissue damage, while releasing the brakes on anti-tumor immune responses, is a worthy aim with promise for enhancing the therapeutic benefit of RT for cancer

Regulatory T cells in radiotherapeutic responses.

Radiation therapy (RT) can extend its influence in cancer therapy beyond what can be attributed to in-field cytotoxicity by modulating the immune system. While complex, these systemic effects can help tip the therapeutic balance in favor of treatment success or failure. Engagement of the immune system is generally through recognition of damage-associated molecules expressed or released as a result of tumor and normal tissue radiation damage. This system has evolved to discriminate pathological from physiological forms of cell death by signaling "danger." The multiple mechanisms that can be evoked include a shift toward a pro-inflammatory, pro-oxidant microenvironment that can promote maturation of dendritic cells and, in cancer treatment, the development of effector T cell responses to tumor-associated antigens. Control over these processes is exerted by regulatory T cells (Tregs), suppressor macrophages, and immunosuppressive cytokines that act in consort to maintain tolerance to self, limit tissue damage, and re-establish tissue homeostasis. Unfortunately, by the time RT for cancer is initiated the tumor-host relationship has already been sculpted in favor of tumor growth and against immune-mediated mechanisms for tumor regression. Reversing this situation is a major challenge. However, recent data show that removal of Tregs can tip the balance in favor of the generation of radiation-induced anti-tumor immunity. The clinical challenge is to do so without excessive depletion that might precipitate serious autoimmune reactions and increase the likelihood of normal tissue complications. The selective modulation of Treg biology to maintain immune tolerance and control of normal tissue damage, while releasing the "brakes" on anti-tumor immune responses, is a worthy aim with promise for enhancing the therapeutic benefit of RT for cancer

Mitochondria and calcium homeostasis are important for irradiated cells to change their autofluorescence.

<p><b>A</b>) Overlay histogram comparing background FL-1 fluorescence in untreated U87 and U87Rho(0) cells. U87 and mitochondria-deficient U87Rho(0) were treated with 10 Gy and FACS-analyzed 24 h later for <b>B</b>) FL-1 autofluorescence and <b>C</b>) cell size. <b>D</b>) Radiation dose-dependent changes in FL-1 autofluorescence in irradiated DC2.4 after 0, 2, 5, and 10 Gy correlate with changes in forward scatter (top) and side scatter (bottom). <b>E</b>) DC2.4 cells were irradiated with 0 or 10 Gy in the presence of 1 µM A23187 or 0.1% DMSO or 5%FBS/PBS and analyzed 24 h later for viability by 7-AAD exclusion (top). Viable cells were compared for cell size (bottom) and FL-1 autofluorescence (middle). Data are mean ± s.e.m. of n = 6 *p<0.05.</p

Intracellular FAD, NAD and NADH rise following irradiation.

<p>Cells were irradiated with 10 Gy or left untreated and incubated for 24 h before harvest and FAD or NAD/NADH assay. <b>A</b>) range of FAD concentrations per 1 million DC2.4. cells (n = 3), <b>B</b>) Mean NADH concentration per 1million cells (n = 2±s.d.), <b>C</b>) mean NAD concentration per 1 million cells of n = 2±s.d., <b>D</b>) ratio of mean NADH/NAD per 1 million cells (n = 2±s.d. *p<0.05).</p

Radiation increases autofluorescence in a dose- and time- dependent fashion.

<p>DC2.4 cells were irradiated or not under standard culture conditions and analyzed by FACS. <b>A</b>) Forward-side scatter dot blot and Fl-1 histogram of untreated cells and cells at 24 h after treatment with 10 Gy. <b>B</b>) (left) Overlay histograms of FL-1 fluorescence in 10 Gy-irradiated cells analyzed at 24, 48 and 72 h and (right) overlay histogram of FL-1 fluorescence after 0, 2, 5 and 10 Gy and analyzed at 48 h. <b>C</b>) Mean FL-1 fluorescence intensity normalized to control of n = 2±s.d. in DC2.4 treated with radiation ranging from 0.005 to 0.5 Gy and analyzed at 48 h after exposure. *p<0.05.</p

Many cell types respond to radiation with a rise in autofluorescence.

<p>Various murine and human cell lines and primary mouse peripheral blood cells were irradiated with 10 Gy (or less when indicated) and left under standard culture conditions for 24 h prior to FACS analysis. Autofluorescence was recorded in FL-1 and cell viability assessed according to 7-AAD dye exclusion in FL-3. <b>A</b>) FL-1 histogram overlays for treated and untreated B16-OVA, 3LL and EG.7-OVA cells. <b>B</b>) Percent increase in mean FL-1 fluorescence and percent loss in viability in the irradiated sample as compared to control of n = 1–8±s.e.m.</p