Page 177 - 2014 Printable Abstract Book
P. 177
(PS2-71) Radiation-induced microRNA in spleen and its modulation by gamma-tocotrienol in
3
2
1
1
hematopoietic recovery. Sanchita P. Ghosh, Ph.D ; Sibyl Swift ; Shukla Biswas ; Parameet Kumar ;
3
4
3
Sharmistha Bhattacharyya ; Martin Hauer-Jensen ; and Roopa Biswas Armed Forces Radiobiology
1
Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD ; Armed Forces
2
Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD ;
Anatomy, Physiology and Genetics, School of Medicine, Uniformed Services University of the Health
3
Sciences, Bethesda, MD ; and Division of Radiation Health, University of Arkansas for Medical Sciences,
Little Rock, AR
4
Among the eight naturally occurring Vitamin E analogs, gamma-tocotrienol (GT3) is a potent
radiation prophylaxis agent in mice after exposure to whole body gamma-radiation. We have shown that
GT3 protected mice from radiation-induced lethality by protecting the hematopoietic system.
Nevertheless, the precise mechanisms underlying the superior radioprotective efficacy of GT3 compared
to alpha tocopherol are not known. This study investigated the microRNA (miRNA) expression profiles in
the spleen following radiation exposure with and without GT3 treatment. The purpose of this study was
to identify microRNA that are regulated during hematopoietic regeneration and the role of GT3 in
modulating these miRNA. CD2F1 mice (12-14 weeks old) were treated with 200 mg/kg of GT3 24 h before
they were exposed to 4 or 8 Gy (0.6 Gy /min) whole body Co-60 radiation. Spleens were collected at days
1, 4 and 15 after irradiation and total RNA was extracted. MicroRNA microarrays (miRbase version 19.0)
were used to study the expression profiling of 1265 unique mature mouse miRNAs using a µParaflo®
microfluidic technology (LC Sciences, USA). MicroRNA expressions were then validated by qRT-PCR
analysis. A significantly higher number of differentially expressed miRNA were identified in the spleen of
mice exposed to 8 Gy vs. 4 Gy. Our analyses indicate that GT3 treatment modulated the expression of
miRNAs, including miR-15b, miR-27b, miR-34a, miR-99b, miR-125b-5p, miR-126-3p, miR-143-5p, miR-
145b, and miR-3107, up to 15 days post-radiation (8 Gy). Subsequently, we validated the expression of
miR-15b, miR-34a, miR-145b, and miR-3107 by specific Taqman-based qRT-PCR assays.
Our data indicate that the mechanism of GT3 in protecting mice from acute hematopoietic injury might
be regulated through the specific targets of miR-15b, miR-27b, miR-34a, miR-99b, miR-125b-5p, miR-126-
3p, miR-143-5p, miR-145b, and miR-3107. Studies are in progress to identify and validate targets of these
miRNAs and associated molecular pathways. (The opinions are the private views of the authors, and are
not necessarily those of the Armed Forces Radiobiology Research Institute, the Uniformed Services
University, or the Department of Defense. This work was supported by US Department of Defense Threat
Reduction Agency grant H.10016_09_AR_R)
(PS2-72) DMFs for treatment of experimental radiation nephropathy with an ACEI and/or an ARB. John
1;2
1
1
E. Moulder, PhD ; Brian L. Fish, BS ; and Eric P. Cohen, MD, Medical College of Wisconsin, Milwaukee,
WI and Zablocki VAMC, Milwaukee, WI
2
1
We have previously shown dose-modifying factors (DMFs) of 1.21-1.23 for mitigation of
experimental radiation nephropathy by an angiotensin converting enzyme (ACEI, captopril) or angiotensin
II (AII) receptor blocker (ARB, losartan). These determinations were done for single doses of total body
irradiation (TBI) at a high dose rate, and with clinically relevant doses of FDA-approved drugs (on an
2
mg/m /day basis). Hematological toxicity was prevented by a bone marrow transplant, and drug therapy
began at 10 days after TBI. We now report a similar study using a treatment regimen, where therapy was
175 | P a g e
3
2
1
1
hematopoietic recovery. Sanchita P. Ghosh, Ph.D ; Sibyl Swift ; Shukla Biswas ; Parameet Kumar ;
3
4
3
Sharmistha Bhattacharyya ; Martin Hauer-Jensen ; and Roopa Biswas Armed Forces Radiobiology
1
Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD ; Armed Forces
2
Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD ;
Anatomy, Physiology and Genetics, School of Medicine, Uniformed Services University of the Health
3
Sciences, Bethesda, MD ; and Division of Radiation Health, University of Arkansas for Medical Sciences,
Little Rock, AR
4
Among the eight naturally occurring Vitamin E analogs, gamma-tocotrienol (GT3) is a potent
radiation prophylaxis agent in mice after exposure to whole body gamma-radiation. We have shown that
GT3 protected mice from radiation-induced lethality by protecting the hematopoietic system.
Nevertheless, the precise mechanisms underlying the superior radioprotective efficacy of GT3 compared
to alpha tocopherol are not known. This study investigated the microRNA (miRNA) expression profiles in
the spleen following radiation exposure with and without GT3 treatment. The purpose of this study was
to identify microRNA that are regulated during hematopoietic regeneration and the role of GT3 in
modulating these miRNA. CD2F1 mice (12-14 weeks old) were treated with 200 mg/kg of GT3 24 h before
they were exposed to 4 or 8 Gy (0.6 Gy /min) whole body Co-60 radiation. Spleens were collected at days
1, 4 and 15 after irradiation and total RNA was extracted. MicroRNA microarrays (miRbase version 19.0)
were used to study the expression profiling of 1265 unique mature mouse miRNAs using a µParaflo®
microfluidic technology (LC Sciences, USA). MicroRNA expressions were then validated by qRT-PCR
analysis. A significantly higher number of differentially expressed miRNA were identified in the spleen of
mice exposed to 8 Gy vs. 4 Gy. Our analyses indicate that GT3 treatment modulated the expression of
miRNAs, including miR-15b, miR-27b, miR-34a, miR-99b, miR-125b-5p, miR-126-3p, miR-143-5p, miR-
145b, and miR-3107, up to 15 days post-radiation (8 Gy). Subsequently, we validated the expression of
miR-15b, miR-34a, miR-145b, and miR-3107 by specific Taqman-based qRT-PCR assays.
Our data indicate that the mechanism of GT3 in protecting mice from acute hematopoietic injury might
be regulated through the specific targets of miR-15b, miR-27b, miR-34a, miR-99b, miR-125b-5p, miR-126-
3p, miR-143-5p, miR-145b, and miR-3107. Studies are in progress to identify and validate targets of these
miRNAs and associated molecular pathways. (The opinions are the private views of the authors, and are
not necessarily those of the Armed Forces Radiobiology Research Institute, the Uniformed Services
University, or the Department of Defense. This work was supported by US Department of Defense Threat
Reduction Agency grant H.10016_09_AR_R)
(PS2-72) DMFs for treatment of experimental radiation nephropathy with an ACEI and/or an ARB. John
1;2
1
1
E. Moulder, PhD ; Brian L. Fish, BS ; and Eric P. Cohen, MD, Medical College of Wisconsin, Milwaukee,
WI and Zablocki VAMC, Milwaukee, WI
2
1
We have previously shown dose-modifying factors (DMFs) of 1.21-1.23 for mitigation of
experimental radiation nephropathy by an angiotensin converting enzyme (ACEI, captopril) or angiotensin
II (AII) receptor blocker (ARB, losartan). These determinations were done for single doses of total body
irradiation (TBI) at a high dose rate, and with clinically relevant doses of FDA-approved drugs (on an
2
mg/m /day basis). Hematological toxicity was prevented by a bone marrow transplant, and drug therapy
began at 10 days after TBI. We now report a similar study using a treatment regimen, where therapy was
175 | P a g e
