131I Induced Hematological Alterations in Rat Blood: Protection by Zinc

The present study was planned to determine the potential of zinc in attenuating the toxicity induced by ¹³¹I in rat blood. Female wistar rats were segregated into four main groups. Animals in Group I served as normal controls; Group II animals were administered a dose of 3.7 Mbq of ¹³¹I (carrier free) intraperitoneally, Group III was supplemented with Zinc in the form of ZnSo₄.7H₂O (227 mg/l drinking water), and Group IV was given a combined treatment of Zinc as well as ¹³¹I, in a similar way as was given to Groups IV and II animals, respectively. The effects of different treatments were studied on various parameters in rat blood including hemoglobin (Hb) levels, % hematocrit, zinc protoporphyrins (ZPP), activities of enzymes which included aminolevulinic acid dehydratase (δ-ALAD) and Na⁺ K⁺ ATPase and uptake of ⁶⁵Zn in blood. The study revealed an increase in the levels of hemoglobin, % hematocrit, activities of δ-ALAD, Na⁺ K⁺ ATPase and uptake of ⁶⁵Zn, 7 days after the ¹³¹I treatment. On the contrary, the levels of ZPP were found to be significantly decreased after ¹³¹I treatment. However, zinc treatment to ¹³¹I-treated animals significantly attenuated the various biochemical and hematological indices. Moreover, zinc treatment to the ¹³¹I-treated animals could significantly decrease the uptake of ⁶⁵Zn, which was increased after ¹³¹I treatment. Based upon these data, the present study suggests that zinc has the potential to attenuate ¹³¹I induced toxicity by restoring the altered hematological indices and biochemical changes.     

Influence of Zinc on the Biokinetics of 65Zn in Brain and Whole Body and Its Bio-distribution in Aluminium-Intoxicated Rats

The present study was designed to understand the influence of zinc (Zn) if any, on the biokinetics of ⁶⁵Zn in brain as well as whole body and its bio-distribution following aluminium (Al) treatment to rats. Male Sprague–Dawley rats weighing 140–160 g were divided into four different groups viz: normal control, aluminium treated (100 mg/kg b.wt./day via oral gavage), zinc treated (227 mg/L in drinking water) and combined aluminium and zinc treated. All the treatments were carried out for a total duration of 8 weeks. Al treatment showed a significant increase in fast component (Tb₁) but revealed a significant decrease in slow component (Tb₂) of biological half-life in brain as well as in whole body. However, Zn supplementation to Al-treated rats reversed the trend in both brain and whole body, which indicates a significant decrease in Tb₁ component while the Tb₂ component was significantly increased. Further, Al treatment showed an increased percent uptake value of ⁶⁵Zn in cerebrum, cerebellum, heart, liver and lungs whereas a decrease in uptake was found only in blood. On the other hand, there was a significant decline in ⁶⁵Zn activity in nuclear and mitochondrial fractions of brain of Al-treated rats. However, Zn treatment reversed the altered ⁶⁵Zn uptake values in different organs as well as in various subcellular fractions. The study demonstrates that Zn shall prove to be effective in regulating the biokinetics of ⁶⁵Zn in brain and whole body and its distribution at the tissue and subcellular levels in Al-treated rats.     

Study to Evaluate Molecular Mechanics behind Synergistic Chemo-Preventive Effects of Curcumin and Resveratrol during Lung Carcinogenesis

Background

The combination approach is the future of the war against cancer and the present study evaluated molecular mechanics behind the synergistic effects of curcumin and resveratrol during lung carcinogenesis.

Methods

The mice were segregated into five groups which included normal control, Benzo[a]pyrene[BP] treated, BP+curcumin treated, BP+resveratrol treated and BP+curcumin+resveratrol treated.

Results

The morphological analyses of tumor nodules confirmed lung carcinogenesis in mice after 22 weeks of single intra-peritoneal[i.p] injection of BP at a dose of 100 mg/Kg body weight. The BP treatment resulted in a significant increase in the protein expressions of p53 in the BP treated mice. Also, a significant increase in the protein expression of phosphorylated p53[ser15] confirmed p53 hyper-phosphorylation in BP treated mice. On the other hand, enzyme activities of caspase 3 and caspase 9 were noticed to be significantly decreased following BP treatment. Further, radiorespirometric studies showed a significant increase in the ¹⁴C-glucose turnover as well as ¹⁴C-gulcose uptake in the lung slices of BP treated mice. Moreover, a significant rise in the cell proliferation was confirmed indirectly by enhanced uptake of ³H-thymidine in the lung slices of BP treated mice. Interestingly, combined treatment of curcumin and resveratrol to BP treated animals resulted in a significant decrease in p53 hyper-phosphorylation, ¹⁴C glucose uptakes/turnover and ³H-thymidine uptake in the BP treated mice. However, the enzyme activities of caspase 3 and caspase 9 showed a significant increase upon treatment with curcumin and resveratrol.

Conclusion

The study, therefore, concludes that molecular mechanics behind chemo-preventive synergism involved modulation of p53 hyper-phosphorylation, regulation of caspases and cellular metabolism enzymes.     

Tumour Control Probability in Cancer Stem Cells Hypothesis

The tumour control probability (TCP) is a formalism derived to compare various treatment regimens of radiation therapy, defined as the probability that given a prescribed dose of radiation, a tumour has been eradicated or controlled. In the traditional view of cancer, all cells share the ability to divide without limit and thus have the potential to generate a malignant tumour. However, an emerging notion is that only a sub-population of cells, the so-called cancer stem cells (CSCs), are responsible for the initiation and maintenance of the tumour. A key implication of the CSC hypothesis is that these cells must be eradicated to achieve cures, thus we define TCP_S as the probability of eradicating CSCs for a given dose of radiation. A cell surface protein expression profile, such as CD44high/CD24low for breast cancer or CD133 for glioma, is often used as a biomarker to monitor CSCs enrichment. However, it is increasingly recognized that not all cells bearing this expression profile are necessarily CSCs, and in particular early generations of progenitor cells may share the same phenotype. Thus, due to the lack of a perfect biomarker for CSCs, we also define a novel measurable TCP_CD+, that is the probability of eliminating or controlling biomarker positive cells. Based on these definitions, we use stochastic methods and numerical simulations parameterized for the case of gliomas, to compare the theoretical TCP_S and the measurable TCP_CD+. We also use the measurable TCP to compare the effect of various radiation protocols.     

Stochastic model for tumor control probability: effects of cell cycle and (a)symmetric proliferation

Background

Estimating the required dose in radiotherapy is of crucial importance since the administrated dose should be sufficient to eradicate the tumor and at the same time should inflict minimal damage on normal cells. The probability that a given dose and schedule of ionizing radiation eradicates all the tumor cells in a given tissue is called the tumor control probability (TCP), and is often used to compare various treatment strategies used in radiation therapy.

Method

In this paper, we aim to investigate the effects of including cell-cycle phase on the TCP by analyzing a stochastic model of a tumor comprised of actively dividing cells and quiescent cells with different radiation sensitivities. Moreover, we use a novel numerical approach based on the method of characteristics for partial differential equations, validated by the Gillespie algorithm, to compute the TCP as a function of time.

Results

We derive an exact phase-diagram for the steady-state TCP of the model and show that at high, clinically-relevant doses of radiation, the distinction between active and quiescent tumor cells (i.e. accounting for cell-cycle effects) becomes of negligible importance in terms of its effect on the TCP curve. However, for very low doses of radiation, these proportions become significant determinants of the TCP. We also present the results of TCP as a function of time for different values of asymmetric division factor.

Conclusion

We observe that our results differ from the results in the literature using similar existing models, even though similar parameters values are used, and the reasons for this are discussed.

     

Siglec-E Promotes β2-Integrin-dependent NADPH Oxidase Activation to Suppress Neutrophil Recruitment to the Lung

Siglec-E is a sialic acid-binding Ig-like lectin expressed on murine myeloid cells. It has recently been shown to function as a negative regulator of β2-integrin-dependent neutrophil recruitment to the lung following exposure to lipopolysaccharide (LPS). Here, we demonstrate that siglec-E promoted neutrophil production of reactive oxygen species (ROS) following CD11b β2-integrin ligation with fibrinogen in a sialic acid-dependent manner, but it had no effect on ROS triggered by a variety of other stimulants. Siglec-E promotion of ROS was likely mediated via Akt activation, because siglec-E-deficient neutrophils plated on fibrinogen exhibited reduced phosphorylation of Akt, and the Akt inhibitor, MK2206, blocked fibrinogen-induced ROS. In vivo imaging showed that siglec-E also promoted ROS in acutely inflamed lungs following exposure of mice to LPS. Importantly, siglec-E-promoted ROS were required for its inhibitory function, as the NADPH oxidase inhibitor, apocynin, reversed the siglec-E-mediated suppression of neutrophil recruitment and blocked neutrophil ROS production in vitro. Taken together, these results demonstrate that siglec-E functions as an inhibitory receptor of neutrophils via positive regulation of NADPH oxidase activation and ROS production. Our findings have implications for the inhibitory role of siglec-9 on human neutrophils in sepsis and acute lung injury.     

Phosphatidic acid phospholipase A1 mediates ER–Golgi transit of a family of G protein–coupled receptors

The coat protein II (COPII)–coated vesicular system transports newly synthesized secretory and membrane proteins from the endoplasmic reticulum (ER) to the Golgi complex. Recruitment of cargo into COPII vesicles requires an interaction of COPII proteins either with the cargo molecules directly or with cargo receptors for anterograde trafficking. We show that cytosolic phosphatidic acid phospholipase A1 (PAPLA1) interacts with COPII protein family members and is required for the transport of Rh1 (rhodopsin 1), an N-glycosylated G protein–coupled receptor (GPCR), from the ER to the Golgi complex. In papla1 mutants, in the absence of transport to the Golgi, Rh1 is aberrantly glycosylated and is mislocalized. These defects lead to decreased levels of the protein and decreased sensitivity of the photoreceptors to light. Several GPCRs, including other rhodopsins and Bride of sevenless, are similarly affected. Our findings show that a cytosolic protein is necessary for transit of selective transmembrane receptor cargo by the COPII coat for anterograde trafficking.     

Identification of kaempferol‐regulated proteins in rat calvarial osteoblasts during mineralization by proteomics

Kaempferol, a flavonoid, promotes osteoblast mineralization in vitro and bone formation in vivo; however, its mechanism of action is yet unknown. We adopted proteomic approach to identify the differential effect of kaempferol on rat primary calvarial osteoblasts during mineralization. The primary rat calvarial osteoblasts were treated with kaempferol (5.0 μM) for 9 days under mineralizing condition that resulted in significant increase in alkaline phosphatase activity and mineralization of the cells. Further, 2‐D analysis of the kaempferol‐treated osteoblast lysates revealed 18 differentially expressed proteins (nine upregulated and nine downregulated) on the basis of >/<2.0‐fold as cut‐off (p<0.01) that were then identified by MALDI‐TOF MS. These included cytoskeletal proteins, intracellular signaling protein, chaperone, extracellular matrix protein, and proteins involved in glycolysis and cell–matrix interactions. Proteomics data were confirmed by Western blotting and quantitative real‐time PCR by randomly selecting two upregulated and two downregulated proteins. Western blot analysis confirmed upregulation of HSP‐70 and cytokeratin‐14 levels, and downregulation of aldose reductase and caldesmon expression. We further demonstrated that kaempferol treatment inhibits aldose reductase activity in osteoblasts indicating an altered cellular metabolism by decelerating polyol pathway that was associated with the kaempferol‐induced osteoblast mineralization. In conclusion, this is a first comprehensive study on the differential regulation of proteins by kaempferol in primary osteoblast, which would further help to elucidate the role of the identified proteins in the process of osteoblast mineralization.     

Mutations in the FAD binding domain cause stress-induced misoxidation of the endoplasmic reticulum oxidoreductase Ero1beta

Disulfide bond catalysis is an essential component of protein biogenesis in the secretory pathway, from yeast through to man. In the endoplasmic reticulum (ER), protein-disulfide isomerase (PDI) catalyzes the oxidation and isomerization of disulfide bonds and is re-oxidized by an endoplasmic reticulum oxidoreductase (ERO). The elucidation of ERO function was greatly aided by the genetic analysis of two ero mutants, whose impairment results from point mutations in the FAD binding domain of the Ero protein. The ero1-1 and ero1-2 yeast strains have conditional and dithiothreitol-sensitive phenotypes, but the effects of the mutations on the behavior of Ero proteins has not been reported. Here, we show that these Gly to Ser and His to Tyr mutations do not prevent the dimerization of Ero1beta or the non-covalent interaction of Ero1beta with PDI. However, the Gly to Ser mutation abolishes disulfide-dependent PDI-Ero1beta heterodimers. Both the Gly to Ser and His to Tyr mutations make Ero1beta susceptible to misoxidation and aggregation, particularly during a temperature or redox stress. We conclude that the Ero FAD binding domain is critical for conformational stability, allowing Ero proteins to withstand stress conditions that cause client proteins to misfold.