Taibah University, Madinah, Saudi Arabia
Medical Laboratories Technology
Two-deoxy-D-glucose (2-DG), an inhibitor of glycolysis differentially enhances the radiation and chemotherapeutic drug induced cell death in cancer cells in vitro, while the local tumor control (tumor regression) following systemic... more
Two-deoxy-D-glucose (2-DG), an inhibitor of glycolysis differentially enhances the radiation and chemotherapeutic drug induced cell death in cancer cells in vitro, while the local tumor control (tumor regression) following systemic administration of 2-DG and focal irradiation of the tumor results in both complete (cure) and partial response in a fraction of the tumor bearing mice. In the present studies, we investigated the effects of systemically administered 2-DG and focal irradiation of the tumor on the immune system in Ehrlich ascites tumor (EAT) bearing Strain ''A'' mice. Markers of different immune cells were analyzed by immune-flow cytometry and secretary cytokines by ELISA, besides monitoring tumor growth. Increase in the expression of innate (NK and monocytes) and adaptive CD4 + cells, and a decrease in B cells (CD19) have been observed after the combined treatment, suggestive of activation of anti-tumor immune response. Interestingly, immature dendritic cells were found to be down regulated, while their functional markers CD86 and MHC II were up regulated in the remaining dendritic cells following the combination treatment. Similarly, decrease in the CD4 + naïve cells with concomitant increase in activated CD4 + cells corroborated the immune activation. Further, a shift from Th2 and Th17 to Th1 besides a decrease in inflammatory cytokines was also observed in the animals showing complete response (cure; tumor free survival). This shift was also complimented by respective antibody class switching followed by the combined treatment. The immune activation or alteration in the homeostasis favoring antitumor immune response may be due to depletion in T regulatory cells (CD4 + CD25 + FoxP3 + ). Altogether, these results suggest that early differential immune activation is responsible for the heterogenous response to the combined treatment. Taken together, these studies for the first time provided insight into the additional mechanisms underlying radio-sensitization by 2-DG in vivo by unraveling its potential as an immunemodulator besides direct effects on the tumor.
- by Jawahar Adhikari and +1
- •
- Cytokines, Multidisciplinary, Mice, Immunity
CD4 ؉ and CD8 ؉ T-cell responses have been shown to be critical for the development and maintenance of acquired resistance to infections with the protozoan parasite Leishmania major. Monitoring the development of immunodominant or... more
CD4 ؉ and CD8 ؉ T-cell responses have been shown to be critical for the development and maintenance of acquired resistance to infections with the protozoan parasite Leishmania major. Monitoring the development of immunodominant or clonally restricted T-cell subsets in response to infection has been difficult, however, due to the paucity of known epitopes. We have analyzed the potential of L. major transgenic parasites, expressing the model antigen ovalbumin (OVA), to be presented by antigen-presenting cells to OVA-specific OT-II CD4 ؉ or OT-I CD8 ؉ T cells. Truncated OVA was expressed in L. major as part of a secreted or nonsecreted chimeric protein with L.
Numerous experimental vaccines have been developed with the goal of generating long-term cell-mediated immunity to the obligate intracellular parasite Leishmania major, yet inoculation with live, wild-type L. major remains the only... more
Numerous experimental vaccines have been developed with the goal of generating long-term cell-mediated immunity to the obligate intracellular parasite Leishmania major, yet inoculation with live, wild-type L. major remains the only successful vaccine in humans. We examined the expression of immunity at the site of secondary, low-dose challenge in the ear dermis to determine the kinetics of parasite clearance and the early events associated with the protection conferred by vaccination with live L. major organisms in C57BL/6 mice. Particular attention was given to the route of vaccination. We observed that the rapidity, strength, and durability of the memory response following subcutaneous vaccination with live parasites in the footpad are even greater than previously appreciated. Antigen-specific gamma interferon (IFN-␥)-producing T cells infiltrate the secondary site by 1.5 weeks, and viable parasites are cleared as early as 2.5 weeks following rechallenge, followed by a rapid drop in IFN-␥ ؉ CD4 ؉ cell numbers in the site. In comparison, intradermal vaccination with live parasites in the ear generates immunity that is delayed in effector cell recruitment to the rechallenge site and in the clearance of parasites from the site. This compromised immunity was associated with a rapid recruitment of interleukin-10 (IL-10)-producing CD4 ؉ T cells to the rechallenge site. Treatment with anti-IL-10-receptor or anti-CD25 antibody enhanced early parasite clearance in ear-vaccinated mice, indicating that chronic infection in the skin generates a population of regulatory cells capable of influencing the level of resistance to reinfection. A delicate balance of effector and regulatory T cells may be required to optimize the potency and durability of vaccines against Leishmaniasis and other intracellular pathogens.
Hydroxychavicol, isolated from the chloroform extraction of the aqueous leaf extract of Piper betle L., (Piperaceae) was investigated for its antifungal activity against 124 strains of selected fungi. The leaves of this plant have been... more
Hydroxychavicol, isolated from the chloroform extraction of the aqueous leaf extract of Piper betle L., (Piperaceae) was investigated for its antifungal activity against 124 strains of selected fungi. The leaves of this plant have been long in use tropical countries for the preparation of traditional herbal remedies. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of hydroxychavicol were determined by using broth microdilution method following CLSI guidelines. Time kill curve studies, post-antifungal effects and mutation prevention concentrations were determined against Candida species and Aspergillus species "respectively". Hydroxychavicol was also tested for its potential to inhibit and reduce the formation of Candida albicans biofilms. The membrane permeability was measured by the uptake of propidium iodide. Hydroxychavicol exhibited inhibitory effect on fungal species of clinical significance, with the MICs ranging from 15.62 to 500 microg/ml for yeasts, 125 to 500 microg/ml for Aspergillus species, and 7.81 to 62.5 microg/ml for dermatophytes where as the MFCs were found to be similar or two fold greater than the MICs. There was concentration-dependent killing of Candida albicans and Candida glabrata up to 8 x MIC. Hydroxychavicol also exhibited an extended post antifungal effect of 6.25 to 8.70 h at 4 x MIC for Candida species and suppressed the emergence of mutants of the fungal species tested at 2 x to 8 x MIC concentration. Furthermore, it also inhibited the growth of biofilm generated by C. albicans and reduced the preformed biofilms. There was increased uptake of propidium iodide by C. albicans cells when exposed to hydroxychavicol thus indicating that the membrane disruption could be the probable mode of action of hydroxychavicol. The antifungal activity exhibited by this compound warrants its use as an antifungal agent particularly for treating topical infections, as well as gargle mouthwash against oral Candida infections.
Leishmaniasis is one of the major tropical parasitic diseases, and the condition ranges in severity from self-healing cutaneous lesions to fatal visceral manifestations. There is no vaccine available against visceral leishmaniasis (VL)... more
Leishmaniasis is one of the major tropical parasitic diseases, and the condition ranges in severity from self-healing cutaneous lesions to fatal visceral manifestations. There is no vaccine available against visceral leishmaniasis (VL) (also known as kala-azar in India), and current antileishmanial drugs face major drawbacks, including drug resistance, variable efficacy, toxicity and parenteral administration. We report here that n-hexane fractions of Artemisia annua leaves (AAL) and seeds (AAS) possess significant antileishmanial activity against Leishmania donovani promastigotes, with GI 50 of 14.4 and 14.6 mg ml "1 , respectively, and the IC 50 against intracellular amastigotes was found to be 6.6 and 5.05 mg ml "1 , respectively. Changes in the morphology of promastigotes and growth reversibility analysis following treatment confirmed the leishmanicidal effect of the active fractions, which presented no cytotoxic effect on mammalian cells. The antileishmanial activity was mediated via apoptosis, as evidenced by externalization of phosphatidylserine, in situ labelling of DNA fragments by terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) and cell-cycle arrest at the sub-G 0 /G 1 phase. High-performance thin-layer chromatography (HPTLC) fingerprinting showed that the content of artemisinin in crude bioactive extracts (~1.4 mg per 100 mg n-hexane fraction) was too low to account for the observed antileishmanial activity. Characterization of the active constituents by GC-MS showed that a-amyrinyl acetate, b-amyrine and derivatives of artemisinin were the major constituents in AAL and cetin, EINECS 211-126-2 and artemisinin derivatives in AAS. Our findings indicate the presence of antileishmanial compounds besides artemisinin in the n-hexane fractions of A. annua leaves and seeds.
Here we report the activity of liposomes comprising egg phosphatidylcholine (PC) and stearylamine (SA) against Leishmania donovani parasites. Both promastigotes and intracellular amastigotes in vitro and in vivo were susceptible to SA-PC... more
Here we report the activity of liposomes comprising egg phosphatidylcholine (PC) and stearylamine (SA) against Leishmania donovani parasites. Both promastigotes and intracellular amastigotes in vitro and in vivo were susceptible to SA-PC liposomes. A single dose of 55 mg of SA-PC liposomes/animal could significantly reduce the hepatic parasite burden by 85 and 68% against recent and established experimental visceral leishmaniasis, respectively, suggesting their strong therapeutic potential.
Sojourners visiting high-altitude (HA) (>2500 m) are susceptible to HA disorders; on the contrary, HA natives are well adapted to the extreme hypoxic environment. High aldosterone levels are believed to be involved in HA disorders, we,... more
Sojourners visiting high-altitude (HA) (>2500 m) are susceptible to HA disorders; on the contrary, HA natives are well adapted to the extreme hypoxic environment. High aldosterone levels are believed to be involved in HA disorders, we, therefore, envisaged role of CYP11B2 gene variants in HA adaptation and therefore investigated the -344T/C, intron-2 conversion (Iw/Ic), K173R, and A5160C polymorphisms. In addition, polymorphisms in AGT, AT1R, ATP1A1, ADRB2, and GSTP1 genes were also investigated. The study comprised of 662 subjects, comprising of 426 Himalayan highlanders (HLs) and 236 lowlanders (LLs). The -344T/C and K173R polymorphisms were found to be in complete linkage disequilibrium. The wild-type allele -344T and combination of wild-type homozygous genotypes between -344T/C, Iw/Ic, and A5160C polymorphisms, containing all the six wild-type alleles were over-represented in the HLs (p < 0.0001, and p = 0.008, respectively). The wild-type haplotypes -344T-Iw, -344T-5160A, and -344T-Iw-5160A also showed over-representation in the HLs (p < 0.0001). Furthermore, greater the number of wild-type alleles, lower was the ARR (p < 0.05). The genotype distribution in remaining genes did not differ. To conclude, the over-representation of wild-type À344T allele, genotype combinations and haplotypes of CYP11B2, and their correlation with lower aldosterone levels associate with HA adaptation in the HLs. Such an allelic presentation in sojourners may help them cope with adverse HA environment.
Hippophae rhamnoides or seabuckthorn is used extensively in Indian and Tibetan traditional medicine for the treatment of circulatory disorders, ischemic heart disease, hepatic injury, and neoplasia. In the present study, we have evaluated... more
Hippophae rhamnoides or seabuckthorn is used extensively in Indian and Tibetan traditional medicine for the treatment of circulatory disorders, ischemic heart disease, hepatic injury, and neoplasia. In the present study, we have evaluated the radioprotective potential of REC-1001, a fraction isolated from the berries of H. rhamnoides. Chemical analysis of the extract indicated that REC-1001 was *68% by weight polyphenols, and contained kaempferol, isorhamnetin, and quercetin. The effect of REC-1001 on modulating radiation-induced DNA damage was determined in murine thymocytes by measuring nonspecific nuclear DNA damage at the whole genome level using the alkaline halo assay and by measuring sequence/gene-specific DNA damage both in nuclear DNA (b-globin gene) and in mitochondrial DNA using a quantitative polymerase chain reaction. Treatment with 10 Gy resulted in a significant amount of DNA damage in the halo assay and reductions in the amplification of both the b-globin gene and mitochondrial DNA. REC-1001 dose-dependently reduced the amount of damage detected in each assay, with the maximum protective effects observed at the highest REC-1001 dose evaluated (250 lg/ml). Studies measuring the nicking of naked plasmid DNA further established the radioprotective effect of REC-1001. To elucidate possible mechanisms of action, the antioxidant properties and the free-radical scavenging activities of REC-1001 were evaluated. REC-1001 dose-dependently scavenged radiation-induced hydroxyl radicals, chemically-generated superoxide anions, stabilized DPPH radicals, and reduced Fe 3þ to Fe 2þ . The results of the study indicate that the REC-1001 extract of H. rhamnoides protects mitochondrial and genomic DNA from radiation-induced damage. The polyphenols/flavonoids present in the extract might be responsible for the free radical scavenging and DNA protection afforded by REC-1001. Environ. Mol. Mutagen. 47:647-656, 2006. V V C 2006 Wiley-Liss, Inc.
Hippophae rhamnoides or seabuckthorn is used extensively in Indian and Tibetan traditional medicine for the treatment of circulatory disorders, ischemic heart disease, hepatic injury, and neoplasia. In the present study, we have evaluated... more
Hippophae rhamnoides or seabuckthorn is used extensively in Indian and Tibetan traditional medicine for the treatment of circulatory disorders, ischemic heart disease, hepatic injury, and neoplasia. In the present study, we have evaluated the radioprotective potential of REC-1001, a fraction isolated from the berries of H. rhamnoides. Chemical analysis of the extract indicated that REC-1001 was *68% by weight polyphenols, and contained kaempferol, isorhamnetin, and quercetin. The effect of REC-1001 on modulating radiation-induced DNA damage was determined in murine thymocytes by measuring nonspecific nuclear DNA damage at the whole genome level using the alkaline halo assay and by measuring sequence/gene-specific DNA damage both in nuclear DNA (b-globin gene) and in mitochondrial DNA using a quantitative polymerase chain reaction. Treatment with 10 Gy resulted in a significant amount of DNA damage in the halo assay and reductions in the amplification of both the b-globin gene and mitochondrial DNA. REC-1001 dose-dependently reduced the amount of damage detected in each assay, with the maximum protective effects observed at the highest REC-1001 dose evaluated (250 lg/ml). Studies measuring the nicking of naked plasmid DNA further established the radioprotective effect of REC-1001. To elucidate possible mechanisms of action, the antioxidant properties and the free-radical scavenging activities of REC-1001 were evaluated. REC-1001 dose-dependently scavenged radiation-induced hydroxyl radicals, chemically-generated superoxide anions, stabilized DPPH radicals, and reduced Fe 3þ to Fe 2þ . The results of the study indicate that the REC-1001 extract of H. rhamnoides protects mitochondrial and genomic DNA from radiation-induced damage. The polyphenols/flavonoids present in the extract might be responsible for the free radical scavenging and DNA protection afforded by REC-1001. Environ. Mol. Mutagen. 47:647-656, 2006. V V C 2006 Wiley-Liss, Inc.
Leishmania donovani promastigote membrane antigens (LAg) encapsulated in positively charged liposomes have been found to induce very significant levels of protection against experimental visceral leishmaniasis. The protectively immunized... more
Leishmania donovani promastigote membrane antigens (LAg) encapsulated in positively charged liposomes have been found to induce very significant levels of protection against experimental visceral leishmaniasis. The protectively immunized animals exhibited profound delayed-type hypersensitivity and antibody responses. The extent of protection induced by the same antigens, however, varied depending on the charge of the vesicles, with maximum induction by positively charged liposomes, followed by neutral liposomes and last negatively charged liposomes. Characterization of LAg and LAg entrapped in liposomes of different charges by Western blot analysis revealed the immunodominance of gp63 in all three vaccine preparations. The strong reactivity of antigens in a restricted antigen profile that included, in addition to gp63, 72-, 52-, 48-, 45-, 39-, and 20-kDa components in neutral and positively charged liposomes contrasted with the reactivity of a greater number of LAg components in negatively charged liposomes. Resistance to visceral leishmaniasis appears to depend on the immunity induced by gp63 and a few select antigens in association with the right liposomes. A striking similarity between the immunogenic profile of partially purified soluble antigens and that of LAg in neutral and positively charged liposomes suggests the potentiality of these antigens in future vaccine studies of L. donovani.
- by N. Ali and +1
- •
- Western blotting, Biological Sciences, Infection and immunity, Mice
Normal tissue toxicity is one of the major limiting factors in cancer therapy. Damage to normal tissues and critical organs restricts the use of higher therapeutic doses thereby compromising the efficacy. The glucose analog... more
Normal tissue toxicity is one of the major limiting factors in cancer therapy. Damage to normal tissues and critical organs restricts the use of higher therapeutic doses thereby compromising the efficacy. The glucose analog 2-deoxy-D-glucose (2-DG), an inhibitor of glycolytic ATP production has been shown to enhance radiation-and chemotherapeutic drug-induced damage in a number of cancer cells under in vitro and in vivo conditions while sparing or protecting normal cells. This review summarizes current understanding on the protection of normal cells and tissues against radiation-and chemotherapeutic drug-induced damage by 2-DG that makes this glucose analog an ideal adjuvant in cancer therapy.
and many other tissues can be easily isolated and expanded in vitro. They are capable of differentiating into different cell types such as osteoblasts, chondrocytes, adipocytes, cardiomyocytes, hepatocytes, endothelial cells and neuronal... more
and many other tissues can be easily isolated and expanded in vitro. They are capable of differentiating into different cell types such as osteoblasts, chondrocytes, adipocytes, cardiomyocytes, hepatocytes, endothelial cells and neuronal cells. Such immense plasticity coupled with their ability to modulate the activity of immune cells makes them attractive for stem cell-based therapy aimed at treating previously incurable disorders. Preclinical studies have reported successful use of MSCs for delivering therapeutic proteins and repairing defects in a variety of disease models. These studies highlighted the in vivo potential of MSCs and their ability to home to injury sites and modify the microenvironment by secreting paracrine factors to augment tissue repair. Their therapeutic applicability has been widened by genetic modification to enhance differentiation and tissue targeting, and use in tissue engineering. Clinical trials for diseases like osteogenesis imperfecta, graft-versus-host disease and myocardial infarction have shown some promise demonstrating the safe use of both allogeneic and autologous cells. However, lack of knowledge of MSC behaviour and responses in vitro and in vivo forces the need for basic and animal studies before heading to the clinic. Contrasting reports on immunomodulatory functions and tumorigenicity along with issues like mode of cell delivery, lack of specific marker, low survival and engraftment require urgent attention to harness the potential of MSC-based therapy in the near future.
Leishmaniasis consists of a complex spectrum of infectious diseases with worldwide distribution of which visceral leishmaniasis or kala-azar caused by Leishmania donovani is the most devastating. In the absence of vaccines, chemotherapy... more
Leishmaniasis consists of a complex spectrum of infectious diseases with worldwide distribution of which visceral leishmaniasis or kala-azar caused by Leishmania donovani is the most devastating. In the absence of vaccines, chemotherapy remains the mainstay for the control of leishmaniasis. The drugs of choice are expensive and associated with multiple adverse side effects. Because of these limitations, the development of new antileishmanial compounds is imperative and plants offer prospects in this regard. The present work was conducted to study the antileishmanial potential of oil from Syzygium aromaticum flower buds (clove). The S. aromaticum oil was characterized by gas chromatography and GC-MS and eugenol as well as eugenyl acetate were found to be the most abundant compounds, composing 59.75 % and 29.24 %, respectively of the oil. Our findings have shown that eugenol-rich essential oil from S. aromaticum (EROSA) possesses significant activity against L. donovani, with 50 % inhibitory concentration of 21±0.16 mg ml "1 and 15.24±0.14 mg ml "1 , respectively, against promastigotes and intracellular amastigotes. Alterations in cellular morphology and growth reversibility assay substantiated the leishmanicidal activity of EROSA. The leishmanicidal effect was mediated via apoptosis as confirmed by externalization of phosphatidylserine, DNA nicking by TdT-mediated dUTP nick-end labelling (TUNEL) assay, dyskinetoplastidy, cell cycle arrest at sub-G 0 -G 1 phase, loss of mitochondrial membrane potential and reactive oxygen species generation. EROSA presented no adverse cytotoxic effects against murine macrophages even at 200 mg ml "1 . Our studies authenticate the promising antileishmanial activity of EROSA, which is mediated by programmed cell death, and, accordingly, EROSA may be a source of novel agents for the treatment of leishmaniasis.
Leishmaniasis is one of the major tropical parasitic diseases, and the condition ranges in severity from self-healing cutaneous lesions to fatal visceral manifestations. There is no vaccine available against visceral leishmaniasis (VL)... more
Leishmaniasis is one of the major tropical parasitic diseases, and the condition ranges in severity from self-healing cutaneous lesions to fatal visceral manifestations. There is no vaccine available against visceral leishmaniasis (VL) (also known as kala-azar in India), and current antileishmanial drugs face major drawbacks, including drug resistance, variable efficacy, toxicity and parenteral administration. We report here that n-hexane fractions of Artemisia annua leaves (AAL) and seeds (AAS) possess significant antileishmanial activity against Leishmania donovani promastigotes, with GI 50 of 14.4 and 14.6 mg ml "1 , respectively, and the IC 50 against intracellular amastigotes was found to be 6.6 and 5.05 mg ml "1 , respectively. Changes in the morphology of promastigotes and growth reversibility analysis following treatment confirmed the leishmanicidal effect of the active fractions, which presented no cytotoxic effect on mammalian cells. The antileishmanial activity was mediated via apoptosis, as evidenced by externalization of phosphatidylserine, in situ labelling of DNA fragments by terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) and cell-cycle arrest at the sub-G 0 /G 1 phase. High-performance thin-layer chromatography (HPTLC) fingerprinting showed that the content of artemisinin in crude bioactive extracts (~1.4 mg per 100 mg n-hexane fraction) was too low to account for the observed antileishmanial activity. Characterization of the active constituents by GC-MS showed that a-amyrinyl acetate, b-amyrine and derivatives of artemisinin were the major constituents in AAL and cetin, EINECS 211-126-2 and artemisinin derivatives in AAS. Our findings indicate the presence of antileishmanial compounds besides artemisinin in the n-hexane fractions of A. annua leaves and seeds.
This study was undertaken to investigate the synergistic interaction between amphotericin B (AmB) and acteoside, isolated from the aerial parts of the shrub Colebrookea oppositifolia (Lamiaceae). Acteoside alone exhibited no intrinsic... more
This study was undertaken to investigate the synergistic interaction between amphotericin B (AmB) and acteoside, isolated from the aerial parts of the shrub Colebrookea oppositifolia (Lamiaceae). Acteoside alone exhibited no intrinsic antifungal activity but showed a potent synergism in combination with AmB against selected pathogenic species, with fractional inhibitory concentration indices in the range of 0.0312-0.1562. The combination of acteoside at 3.12 and 12.5 mg ml -1 with subinhibitory concentrations of AmB resulted in a potent fungicidal effect and also exhibited a significantly extended post-antifungal effect. Furthermore, the combination also reduced the minimum biofilm reduction concentration values of AmB (2-16-fold) in preformed biofilms of Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus. There was decreased viability of the cells, increased uptake of propidium iodide and enhanced leakage of 260 nm-absorbing material by Candida albicans cells when exposed to AmB in the presence of acteoside. The reason for potentiation is likely to be that the subinhibitory concentrations of AmB facilitated the uptake of acteoside, which resulted in increased killing of the fungal cells. Administration of acteoside in mice at up to 2000 mg (kg body weight) "1 by the intraperitoneal or oral route produced no overt toxicity. The data presented here support synergism between acteoside and AmB, and it is therefore proposed that a prospective new management strategy for therapeutic application of this combination should be explored.
RuvB protein belongs to AAA+ family of enzymes involved in diverse cellular activities. In addition to the annotated two RuvB proteins in Plasmodium falciparum database, we report that a third RuvB protein is also present. The amino acid... more
RuvB protein belongs to AAA+ family of enzymes involved in diverse cellular activities. In addition to the annotated two RuvB proteins in Plasmodium falciparum database, we report that a third RuvB protein is also present. The amino acid sequence analysis has revealed that P. falciparum RuvB3 (PfRuvB3) possesses Walker motif A, Walker motif B, sensor I and sensor II conserved motifs similar to yeast and human RuvB like proteins. The phylogenetic analysis revealed that PfRuvB3 is closely related to yeast RuvB like proteins which are essential for the survival of yeast. The biochemical characterization of recombinant PfRuvB3 confirms its ssDNA dependent ATPase activity. Using the truncated derivatives we show that Walker motif A is essential for the enzymatic activity of PfRuvB3. Using the immunodepletion assays we further show that the ATPase activity is attributable to PfRuvB3 protein. The endogenous P. falciparum RuvB3 contains the characteristic ATPase and some DNA helicase activities. The confocal microscopy analysis showed that this protein is mainly expressed during intraerythrocytic schizont stages of the parasite and is localized to the nuclear region. Once merozoite comes out from schizont, PfRuvB3 protein distinctly relocalized to the subnuclear region. The co-localization studies with a nucleolar marker PfNop1 further suggest that in P. falciparum RuvB3 localizes into a discrete nuclear compartment. On the basis of these studies it can be speculated that P. falciparum RuvB3 is most likely required for intraerythrocytic schizogony.
Present study was undertaken to evaluate the radioprotective ability of total polyphenols extracted from edible portion (epicarp and mesocarp) of apple. Prior administration of apple polyphenols to murine thymocytes significantly... more
Present study was undertaken to evaluate the radioprotective ability of total polyphenols extracted from edible portion (epicarp and mesocarp) of apple. Prior administration of apple polyphenols to murine thymocytes significantly countered radiation induced DNA damage (evaluated by alkaline halo assay) and cell death (trypan blue exclusion method) in a dose dependent manner maximally at a concentration of 2 and 0.2 mg/ml respectively. Apple polyphenols in a dose dependent fashion inhibited both radiation or Fenton reaction mediated 2-deoxyribose (2-DR) degradation indicating its ability to scavenge hydroxyl radicals and this activity was found to be unaltered in presence of simulated gastric juice. Similarly apple polyphenols in a dose dependent fashion scavenged DPPH radicals (maximum 69% at 1 mg/ml), superoxide anions (maximum 88% at 2 mg/ml), reduced Fe 3+ to Fe 2+ (maximum at 1 mg/ml) and inhibited Fenton reaction mediated lipid peroxidation (maximum 66% at 1.5 mg/ml) further establishing its antioxidative properties. Studies carried out with plasmid DNA revealed the ability of apple polyphenols to inhibit radiation induced single as well as double strand breaks. The results clearly indicate that apple polyphenols have significant potential to protect cellular system from radiation induced damage and ability to scavenge free radicals might be playing an important role in its radioprotective manifestation. (Mol Cell Biochem 288: [37][38][39][40][41][42][43][44][45][46] 2006)
Human mesenchymal stem cells (hMSCs) present in the bone marrow are the precursors of osteoblasts, chondrocytes and adipocytes, and hold tremendous potential for osteoregenerative therapy. However, achieving directed differentiation into... more
Human mesenchymal stem cells (hMSCs) present in the bone marrow are the precursors of osteoblasts, chondrocytes and adipocytes, and hold tremendous potential for osteoregenerative therapy. However, achieving directed differentiation into osteoblasts has been a major concern. The use of lithium for enhancing osteogenic differentiation has been documented in animal models but its effect in humans is not clear. We, therefore, performed high throughput transcriptome analysis of lithium-treated hMSCs to identify altered gene expression and its relevance to osteogenic differentiation. Our results show suppression of proliferation and enhancement of alkaline phosphatase (ALP) activity upon lithium treatment of hMSCs under non-osteogenic conditions. Microarray profiling of lithium-stimulated hMSC revealed decreased expression of adipogenic genes (CEBPA, CMKLR1, HSD11B1) and genes involved in lipid biosynthesis. Interestingly, osteoclastogenic factors and immune responsive genes (IL7, IL8, CXCL1, CXCL12, CCL20) were also downregulated. Negative transcriptional regulators of the osteogenic program (TWIST1 and PBX1) were suppressed while genes involved in mineralization like CLEC3B and ATF4 were induced. Gene ontology analysis revealed enrichment of upregulated genes related to mesenchymal cell differentiation and signal transduction. Lithium priming led to enhanced collagen 1 synthesis and osteogenic induction of lithium pretreated MSCs resulted in enhanced expression of Runx2, ALP and bone sialoprotein. However, siRNA-mediated knockdown of RRAD, CLEC3B and ATF4 attenuated lithium-induced osteogenic priming, identifying a role for RRAD, a member of small GTP binding protein family, in osteoblast differentiation. In conclusion, our data highlight the transcriptome reprogramming potential of lithium resulting in higher propensity of lithium ''primed'' MSCs for osteoblastic differentiation.