Fibronectin modified alginate coating enhances cell targeting and homing to bone marrow in BALB/c mice

AIM

Stem cell homing to bone marrow (BM) suffers from premature differentiation of transfused cells within the blood stream, thereby reducing the efficiency of stem cell transplantation (SCT). This work is attempted to enhance the homing of cells in BM.

METHODS

Fibronectin modified alginate (A-F) was prepared and used to coat the cells. Biodistribution and survival advantage provided by A-F coating was evaluated in BALB/c mice.

RESULTS

The A-F conjugate showed characteristic FT-IR peaks of alginate at 3308 cm^-1 and 1634 cm^-1, and Fibronectin peak at 675 cm^-1. The A-F coating prevented antibodies from binding to their respective cell surface receptors. The A-F coat abolished haemagglutination. Significant distribution of coated cells was observed in BM after 24 h. This provided protection to 7 Gy irradiated mice. The A-F coating showed no histological toxicity in vivo.

CONCLUSION

The coating formulation is likely to be useful for shielding clinically relevant cell types to improve targeting for organ regeneration.

Podophyllum hexandrum and its active constituents: Novel radioprotectants

Human exposure to radiation has expanded considerably in recent years, due to a wide range of medical, agricultural, and industrial applications. Despite its beneficial utilities, radiation is also known to have a deleterious effect on cells and tissues, largely through the creation of free radicals, which cause severe damage to biological systems through processes such as DNA double/single-strand fragmentation, protein modification, and upregulation of lipid peroxidation pathways. In addition, radiation damages genetic material while inducing hereditary genotoxicity. Developing measures to counter radiation-induced damage is thus considered to be of significant importance. Considering the inherent capability of plants to survive radiative conditions, certain plants and natural compounds have been the subject of investigations to explore and harness their natural radioprotective abilities. Podophyllum hexandrum, an Indian medicinal plant with several known traditional phytotherapeutic uses, is considered in particular to be of immense therapeutic importance. Recent studies have been conducted to validate its radioprotective potential alongside discovering its protective mechanisms following γ-radiation-induced mortality and disorder in both mice and human cells. These findings show that Podophyllum and its constituents/natural compounds protect the lungs, gastrointestinal tissues, hemopoietic system, and testis by inducing DNA repair pathways, apoptosis inhibition, free radical scavenging, metal chelation, anti-oxidation and anti-inflammatory mechanisms. In this review, we have provided an updated, comprehensive summary of ionizing radiations and their impacts on biological systems, highlighting the mechanistic and radioprotective role of natural compounds from Podophyllum hexandrum.

A Combination of Podophyllotoxin and Rutin Alleviates Radiation-Induced Pneumonitis and Fibrosis through Modulation of Lung Inflammation in Mice

Pneumonitis and pulmonary fibrosis are predominant consequences of radiation exposure, whether planned or accidental. The present study, demonstrates radioprotective potential of a formulation, prepared by combining podophyllotoxin and rutin (G-003M), in mice exposed to 11 Gy thoracic gamma radiation (TGR). Treated mice were observed for survival and other symptomatic features. Formation of reactive oxygen species (ROS)/nitric oxide (NO) was measured in bronchoalveolar lavage cells. DNA damage and cell death were assessed in alveolar cells by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. Total protein (TP), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) were measured in bronchoalveolar lavage fluid (BALF)/serum of mice to assess lung vascular permeability. Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), cluster of differentiation 45, inducible nitric oxide synthase (iNOS), and nitrotyrosine were also estimated in lungs/BALF of differentially treated mice. Our observations revealed 100% survival in G-003M-pretreated mice against 66.50% in 11 Gy TGR exposed. Other symptoms like reduction in graying of hair, weight loss, and breathing rate were also observed in pretreated groups. Significant decline in ROS/NO and cell death in formulation pretreated mice were also observed. Decreased level of TP, LDH, and ALP in BALF/serum samples revealed G-003M-induced inhibition in lung permeability. Level of IL-6, TNF-α, and TGF-β1 in the lungs of these mice was found corresponding to control group at 8 weeks posttreatment. On the contrary, these cytokines raised significantly in 11 Gy TGR-exposed mice. Lung pneumonitis and fibrosis were found significantly countered in these mice. The observations revealed that G-003M could regulate immune system by curtailing radiation-induced oxidative and inflammatory stress, which has helped in minimizing radiation-inflicted pneumonitis and fibrosis.

Radiation-induced hematopoietic myelosuppression and genotoxicity get significantly countered by active principles of Podophyllum hexandrum: A study in strain 'A' mice

PURPOSE

To investigate the protective role of a novel formulation, prepared by a combination of three active principles isolated from Podophyllum hexandrum (G-002M), against radiation- mediated hematopoietic suppression and cytogenetic aberrations in lethally irradiated mice.

MATERIALS AND METHODS

G-002M, a combination of podophyllotoxin, podophyllotoxin-β-D glucoside and rutin, was administered intramuscularly in mice (- 1 h) to radiation (9 Gy) exposure. The animals were autopsied at different time intervals for further studies.

RESULTS

Loss of bone marrow progenitor cells, altered myeloid/erythroid ratio, serum erythropoietin and pancytopenia in irradiated mice was found significantly (p < 0.001) ameliorated in G-002M pre-administered mice within 30 d. Bcl-2 (B-cell lymphoma 2) and BAX (Bcl-2-associated X) protein expression was also positively (p < 0.001) countered in these mice. Chromosomal aberrations in 30 d were found remarkably (p < 0.001) reduced in marrow of G-002M pretreated mice. Accelerated antioxidants, reduced DNA damage, stimulated lymphocyte proliferation and minimal cellular atrophy in spleen were some of the other key features observed in G-002M administered mice.

CONCLUSIONS

Reduction in hematopoietic aplasia and chromosomal aberrations, besides, early recovery in bone marrow and spleen of G-002M pretreated mice, could be attributed to its free radical scavenging, DNA protecting and apoptotic proteins modulating ability against radiation.

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.

Alleviation of radiation-induced genomic damage in human peripheral blood lymphocytes by active principles of Podophyllum hexandrum: an in vitro study using chromosomal and CBMN assay

This study was aimed to evaluate the protection against radiation of human peripheral blood lymphocytic DNA by a formulation of three isolated active principles of Podophyllum hexandrum (G-002M). G-002M in various concentrations was administered 1h prior to irradiation in culture media containing blood. Radioprotective efficacy of G-002M to lymphocytic DNA was estimated using various parameters such as dicentrics, micronuclei (MN), nucleoplasmic bridges (NPB) and nuclear buds (NuB) in binucleated cells. Certain experiments to ascertain the G2/M arrest potential of G-002M were also conducted. It was effective in arresting the cells even at half of the concentration of colchicine used. Observations demonstrated a radiation-dose-dependent increase in dicentric chromosomes (DC), acentric fragments, MN, NPB and NuB upto 5Gy. These changes were found significantly decreased by pre-administration of G-002M. A highly significant dose modifying factor (DMF) 1.43 and 1.39 based on dicentric assay and cytokinesis block micronuclei assay, respectively, was observed against 5Gy exposure in the current experiments. G-002M alone in its effective dose did not induct any change in any of the parameters mentioned above. Observations on cell cycle arrest by G-002M showed that the formulation has potential in arresting cells at G2/M, compared with colchicine. Based on significant DMF at highest radiation dose (5Gy) studied currently and meaningful reduction in radiation-induced chromosomal aberrations, we express that G-002M has a potential of minimising radiation-induced DNA (cytogenetic) damage.