Podophyllotoxin and Rutin Modulate M1 (iNOS+) Macrophages and Mitigate Lethal Radiation (LR) Induced Inflammatory Responses in Mice.

Accidental exposure to lethal doses of Gamma radiation leads to the systemic inflammatory syndrome which causes mortality. In view of this, management of hemopoietic syndrome by modulating pro-inflammatory response in clinically manageable time period seems to be the most appropriate strategy for encountering radiation induced damage and recovery. As both tissue and peripheral macrophages are critical for the management of radiation induced injuries, we have unraveled the immunomodulatory potential of radioprotective formulation (G-003M) on peripheral macrophages populations in this study. G-003M inhibited lethal radiation induced NO and Th1 effector cytokines in the exposed macrophages indicating its M1 dim polarizing capacity. In similar lines, conditioning of mice with G-003M before lethal irradiation (LR) inhibited LR induced titre of Th1 effector cytokines in both serums as well as in lung, small intestine, and spleen tissue confirming its immunomodulatory potential. G-003M potentially down modulated inflammatory response in LPS induced inflammatory model and enhanced M2 polarization of iNOS+ M1 effector macrophages providing a molecular hint on G-003M mechanism of action on macrophages. These observations revealed that G-003M potentially modulate pro-inflammatory programming of macrophages and mitigate radiation-induced inflammatory stress which is believed to contribute significantly to radioprotective attribute of G-003M. In this study, we demonstrate that Rutin and Podophyllotoxin drive M1dim/M2 polarization of LR primed macrophages apart from protecting DNA from radiation. These drugs have the capacity to programme innate immune cells like macrophages which may be involved in homeostasis during recovery.

Targeting DNA Repair through Podophyllotoxin and Rutin Formulation in Hematopoietic Radioprotection: An in Silico, in Vitro, and in Vivo Study.

Drug discovery field has tremendously progressed during last few decades, however, an effective radiation countermeasure agent for the safe administration to the victims of radiation exposure is still unavailable. This multi-model study is aimed at elucidating the mechanistic aspects of a novel podophyllotoxin and rutin combination (henceforth referred as G-003M) in the hematopoietic radioprotection and its involvement in the DNA damage and repair signaling pathways. Using in silico study, we identified the binding sites and structural components of G-003M and validated in vitro. We further studied various in vivo endpoints related to the DNA repair and cell death pathways in mice pre-administered with G-003M, irradiated and subsequently euthanized to collect blood and bone marrow cells. In silico study showed the binding of podophyllotoxin to ß-tubulin and presence of a functional hydroxyl group in the rutin, suggested their involvement in G2/M arrest and the free radical scavenging respectively. This experimentation was further validated through in vitro studies. In vivo mice studies confirmed that G-003M pre-administration attenuated DNA damage and enhanced repair after whole body exposure. We further noticed a decrease in the levels of γH2AX, p53BP1, and ATM kinase and an increase in the levels of DNA pk, Ku 80, Ligase IV, Mre 11, Rad 50 and NBS 1 in the blood and bone marrow cells of the G-003M pre-administered and irradiated mice. We noticed an overall increase in the pro-survival factors in the G-003M pre-treated and irradiated groups establishing the radioprotective efficacy of this formulation. The lead obtained from this study will certainly help in developing this formulation as a safe and effective radioprotector which could be used for humans against any planned or emergency exposure of radiation.

γH2AX formation kinetics in PBMCs of rabbits exposed to acute and fractionated radiation and attenuation of focus frequency through preadministration of a combination of podophyllotoxin and rutin hydrate.

DNA damage can be assessed by the quantitation of γH2AX foci that form at DSB sites. This study examines the generation and persistence of γH2AX foci, variability in foci size after acute and fractionated radiation exposure, and the effect of pretreatment with a safe radioprotective formulation termed G-003M on foci generation and persistence. G-003M contains a combination of podophyllotoxin and rutin hydrate, and was administered intramuscularly to rabbits 1 hr prior to Co(60) gamma irradiation. Rabbits were assigned to one of the following treatment groups: untreated, G-003M alone, irradiated (single dose 8 Gy, fractionated 2 Gy/day for 4 days or single dose 2 Gy) or G-003M preadministration followed by radiation exposure. Foci continuously persisted for a week in peripheral blood mononuclear cells of rabbits exposed to a single 8 Gy dose. However, the number of foci gradually decreased after reaching a maximum at 1 h. In rabbits exposed to fractionated radiation, foci detected 1 hr after the final exposure were significantly larger (P < 0.001) than in rabbits exposed to a single 8 Gy dose, but disappeared completely after 24 h. In both groups, foci reappeared on days 11-15 in terminally ill animals. G-003M pretreatment significantly (P < 0.05) attenuated the formation of γH2AX foci in all irradiated rabbits. This study reveals that γH2AX focus assessment could be used to confirm radiation exposure, that focus size reflects the type of radiation exposure (acute or fractionated), that the re-appearance of foci is a strong indicator of imminent death in animals, and that G-003M provides protection against radiation. Environ. Mol. Mutagen. 57:455-468, 2016. © 2016 Wiley Periodicals, Inc.

Modification of radiation-induced DNA double strand break repair pathways by chemicals extracted from Podophyllum hexandrum: an in vitro study in human blood leukocytes.

Radiation exposure is a serious threat to biomolecules, particularly DNA, proteins and lipids. Various exogenous substances have been reported to protect these biomolecules. In this study we explored the effect of pre-treatment with G-002M, a mixture of three active derivatives isolated from the rhizomes of Podophyllum hexandrum, on DNA damage response in irradiated human blood leukocytes. Blood was collected from healthy male volunteers, preincubated with G-002M and then irradiated with various doses of radiation. Samples were analyzed using flow cytometry to quantify DNA double strand break (DSB) biomarkers including γ-H2AX, P53BP1 and levels of ligase IV. Blood samples were irradiated in vitro and processed to determine time and dose-dependent kinetics. Semiquantitative RT-PCR was performed at various time points to measure gene expression of DNA-PKcs, Ku80, ATM, and 53BP1; each of these genes is involved in DNA repair signaling. Pre-treatment of blood with G-002M resulted in reduction of γ-H2AX and P53BP1 biomarkers levels and elevated ligase IV levels relative to non-G-002M-treated irradiated cells. These results confirm suppression in radiation-induced DNA DSBs. Samples pre-treated with G-002M and then irradiated also showed significant up-regulation of DNA-PKcs and Ku80 and downregulation of ATM and 53BP1 gene expressions, suggesting that G-002M plays a protective role against DNA damage. The protective effect of G-002M may be due to its ability to scavange radiation-induced free radicals or assist in DNA repair. Further studies are needed to decipher the role of G-002M on signaling molecules involved in radiation-induced DNA damage repair pathways.

Radioprotective and antioxidant activity of fractionated extracts of berries of Hippophae rhamnoides.

Plants are an abundant source of medicinal compounds, some of which are useful in combating free radical-mediated oxidative stress. In the present study, initially two fractions designated REC-1001 (flavonoid-rich fraction) and REC-1002 (flavonoid-poor fraction) of Hippophae rhamnoides were screened on the basis of their reducing power in the aqueous phase. REC-1001 was selected for further study, since it exhibited 27.38 times higher antioxidant activity than REC-1002. REC-1001 also showed significant (P < .05) membrane protection potential at 50 microg/mL, which was attributed to its ability to scavenge peroxyl radicals (64.82 +/- 1.25% scavenging within 1,440 min). A significant (P < .05) difference of 67.02% in free radical scavenging activity at 1,000 ng/mL between REC-1001 and vitamin E demonstrated the extract fraction's worth in radiation protection. Such activities were attributed to the presence of quercetin, isorhamnetin, and kaempferol in this fraction. Further, REC-1001 was found to be nontoxic up to 200 mg/kg of body weight. This research suggests that the REC-1001 fraction of H. rhamnoides extract is a safe and effective antioxidant nutraceutical product.