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Ananda S Prasad

Publications and source records attributed to Ananda S Prasad.

11 recordsLinked to original sources

Evidence for reprogramming global gene expression during zinc deficiency in the HUT-78 cell line.

OBJECTIVE: Investigations using cell lines, primary cells, animal models, and human subjects have provided data to indicate that zinc-deficient conditions affect immune functioning of myeloid and lymphoid cells. We hypothesized that zinc-deficient conditions alone may induce the expression of genes in lymphoid cells, which favor enhanced responses to myeloid molecules even in the absence of myeloid cells or myeloid factors. Our objective was to investigate the effects of low zinc-induced alterations in gene expression in a single lymphoid cell line in the absence of influences from growth factors and/or cytokines generated by other cell types also being affected by low zinc status. METHODS: Microarray analysis of non-stimulated and phytohemagglutinin-p/phorbol 12-myristate 13-acetate-stimulated zinc-deficient and zinc-adequate human-derived HUT-78 (TH(0)) lymphoblasts was used to identify changes in gene expressions associated solely with zinc-deficient status in these cells. RESULTS: Overall, gene expression for molecules that would increase T-lymphocyte response to signals from myeloid cells such as cytokine receptors and selected adhesion molecules were upregulated, whereas those associated with T-lymphocyte-directed immune functions, interleukin-2 and interleukin-6 receptors, the cytokine interleukin-4, and zinc finger transcription factors were downregulated. Analysis of selected data obtained from healthy, but mildly zinc-deficient human subjects corroborated observations obtained from low zinc-altered gene expression in HUT-78 cells. CONCLUSION: These data provide evidence for a shift in gene expression of molecules that would increase lymphoid responses to myeloid driven pathways during periods of zinc deficiency even in the absence of myeloid-derived stimuli.

Cell Cycle↗

A new mutation in exon 3 of the SCL39A4 gene in a Tunisian family with severe acrodermatitis enteropathica.

Acrodermatitis enteropathica is a rare autosomal recessive disease that manifests as an inability of the affected individual to absorb intestinal zinc, and therefore patients have nutritional zinc deficiency. Without zinc therapy, this condition is fatal. Mutations in the SLC39A4 gene are responsible for acrodermatitis enteropathica. This gene encodes one member of a human zinc/iron-regulated transporter-like protein, also known as ZIP4, and consists of 12 exons and spans about 4.7 kb. We describe a novel mutation in a Tunisian family in which a chain termination codon in exon 3 yielded a truncated ZIP4 zinc transporter protein.

Acrodermatitis↗

Correction of interleukin-2 gene expression by in vitro zinc addition to mononuclear cells from zinc-deficient human subjects: a specific test for zinc deficiency in humans.

A nutritional deficiency of zinc in humans is widespread in the developing world, and a conditioned zinc deficiency is observed in many diseased states, the elderly population, and pregnant women of both developed and developing nations. It was recently reported that zinc is required for Nuclear Factor-kappaB (NF-kappaB) activation and gene expressions of both interleukin-2 (IL-2) and interleukin-2 receptor alpha (IL-2Ralpha) and beta in HUT-78, a Th0 human malignant lymphoblastoid cell line. In this study, it has been reported for the first time that zinc is also required for gene expression of IL-2 and IL-2Ralpha in primary cells. Isolated peripheral blood mononuclear cells (MNCs) from zinc-deficient elderly subjects was used for this study. NF-kappaB activation was shown to have decreased in the MNCs from zinc-deficient subjects, which was corrected by in vivo zinc supplementation. It was further shown that either in vivo zinc supplementation or the addition of zinc in vitro to MNCs from zinc-deficient subjects results in correction of the gene expression of IL-2 and IL-2Ralpha. Therefore, it was proposed that in vitro addition of zinc to MNCs for correction of gene expression of IL-2 in humans may be used as a specific test for zinc deficiency. Although currently no known specific laboratory test exists for the diagnosis of zinc deficiency in humans, the use of correction of IL-2 messenger RNA (mRNA) with in vitro zinc addition to MNCs from zinc-deficient subjects may be very useful.

Aged↗

Antioxidant effect of zinc in humans.

Oxidative stress is known to be an important contributing factor in many chronic diseases. We tested the hypothesis that in healthy normal volunteers zinc acts as an effective anti-inflammatory and antioxidant agent. Ten normal volunteers were administered daily oral zinc supplementation (45 mg zinc as gluconate) and 10 volunteers received placebo for 8 weeks. Plasma zinc, MDA, HAE, and 8-OHdG levels; LPS-induced TNF-alpha and IL-1beta mRNA; and ex vivo TNF-alpha-induced NF-kappaB activity in mononuclear cells (MNC) were determined before and after supplementation. In subjects receiving zinc, plasma levels of lipid peroxidation products and DNA adducts were decreased, whereas no change was observed in the placebo group. LPS-stimulated MNC isolated from zinc-supplemented subjects showed reduced mRNA for TNF-alpha and IL-1beta compared to placebo. Ex vivo, zinc protected MNC from TNF-alpha-induced NF-kappaB activation. In parallel studies using HL-60, a promyelocytic cell line, we observed that zinc enhances the upregulation of mRNA and DNA-specific binding for A20, a transactivating factor which inhibits the activation of NF-kappaB. Our results suggest that zinc supplementation may lead to downregulation of the inflammatory cytokines through upregulation of the negative feedback loop A20 to inhibit induced NF-kappaB activation. Zinc administration to human subjects with conditions associated with increased oxidative stress should be explored.

8-Hydroxy-2'-Deoxyguanosine↗

Differential expression of hZnT-4 in human prostate tissues.

BACKGROUND: Altered zinc levels in prostate benign prostatic hyperplasia (BPH) and carcinoma is well documented. It is not known whether loss of zinc, necessary to restrain aggressive growth, results from loss of a single specific or multiple zinc transporters. METHODS: Human prostate tissues from patients who underwent radical prostatectomy were screened by RT-PCR analysis for five zinc transporters. Relative cDNA expression was determined in normal, BPH, and tumor specimens and four prostate epithelial cell lines. RESULTS: Surgical specimens were obtained from patients with assigned Gleason scores ranging from 5 to 9. Relative expression of hZIP-1 and hZnT-1 were prominent in most samples with relatively lesser degree of expression of hZIP-2 and no detectable expression of hZnT-3. Expression of hZnT-4 was decreased in BPH and tumor samples compared to normal tissue. CONCLUSIONS: These data suggest that zinc homeostasis in normal prostate tissues results from an interplay of multiple transporters and decreased hZnT-4 expression is associated with prostate tissue abnormalities independent of total cellular zinc content.

Base Sequence↗

Zinc modulates mRNA levels of cytokines.

Zinc plays an important role in cell-mediated immune function. Altered cellular immune response resulting from zinc deficiency leads to frequent microbial infections, thymic atrophy, decreased natural killer activity, decreased thymic hormone activity, and altered cytokine production. In this study, we examined the effect of zinc deficiency on IL-2 and IFN-gamma in HUT-78 (Th0) and D1.1 (Th1) cell lines and TNF-alpha, IL-1 beta, and IL-8 in the HL-60 (monocyte-macrophage) cell line. The results demonstrate that zinc deficiency decreased the levels of IL-2 and IFN-gamma cytokines and mRNAs in HUT-78 after 6 h of PMA/p-phytohemagglutinin (PHA) stimulation and in D1.1 cells after 6 h of PHA/ionomycin stimulation compared with the zinc-sufficient cells. However, zinc deficiency increased the levels of TNF-alpha, IL-1 beta, and IL-8 cytokines and mRNAs in HL-60 cells after 6 h of PMA stimulation compared with zinc-sufficient cells. Actinomycin D study suggests that the changes in the levels of these cytokine mRNAs were not the result of the stability affected by zinc but might be the result of altered expression of these cytokine genes. These data demonstrate that zinc mediates positively the gene expression of IL-2 and IFN-gamma in the Th1 cell line and negatively TNF-alpha, IL-1 beta, and IL-8 in the monocyte-macrophage cell line. Our study shows that the effect of zinc on gene expression and production of cytokines is cell lineage specific.

Cytokines↗

Zinc deficiency.

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Diet↗

Zinc in cancer prevention.

Epidemiologic studies suggest that zinc deficiency may be associated with increased risk of cancer. However, few studies have been conducted with zinc supplementation in animals and humans. Most previous intervention studies have used zinc in combination with several other micronutrients, which make them difficult to interpret. Zinc supplementation is associated with decreased oxidative stress and improved immune function, which may be among the possible mechanisms for its cancer preventive activity. Preclinical and clinical studies need to investigate modulation of genetic and epigenetic pathways of carcinogenesis by zinc.

Animals↗

Zinc enhances the expression of interleukin-2 and interleukin-2 receptors in HUT-78 cells by way of NF-kappaB activation.

Production of interleukin (IL)-2 is decreased in zinc-deficient human beings, and zinc is essential to IL-2-mediated T-cell activation. We used a human Th(0) malignant lymphoblastoid cell line, HUT-78, to study the effect of zinc on IL-2 production in PHA/PMA activated T-cells. In zinc-deficient cells, the gene expression of IL-2 was decreased by 50% compared with that in zinc-sufficient cells. The effect of zinc was specific and at the transcriptional level. We also showed a significant effect of zinc on the gene expression of IL-2 receptors alpha and beta. Binding of NF-kappaB (a zinc-dependent transcription factor) to DNA was decreased in zinc-deficient cells. Using transfection of expression vectors of anti-sense NF-kappaB p105 (precursor of NF-kappaB p50) in cells, we showed that a decrease in gene expression of IL-2 and IL-2 Ralpha may be partly due to decreased activation of NF-kappaB in zinc-deficient cells. Our studies demonstrate, for the first time, the role of zinc in gene expression of IL-2 and its receptors in HUT-78 cells. We also document that the binding of NF-kappaB to DNA was adversely affected, thereby decreasing the gene expression of IL-2 and IL-2 Ralpha in zinc-deficient HUT-78 cells.

Cell Line↗