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2.
Lancet Reg Health Southeast Asia ; 6: 100071, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37383344

RESUMO

Hidden Hunger arising from nutritional iron-, folate-, and vitamin-B12-deficiencies is exceedingly common in India and has profound negative impacts on anaemia, on pregnancy, and on embryonic-foetal neurodevelopment in utero, which predisposes to NTDs and psychological-psychiatric manifestations in childhood. Whereas younger-to-middle-aged Indians fail to perform at maximum potential, the elderly are at risk for calamitous neurologic events. However, these micronutrient-deficiencies are eminently correctable through food-fortification. Therefore, the Indian Government can no longer afford the luxury of inaction by either denying or downplaying the gravity of this problem. What is critically needed from India's leaders is an urgent, clear-eyed reappraisal and act of anagnorisis-(an often startling self-recognition and discovery of a profoundly serious error and tragic flaw)-in failing to confront this problem for decades. Only when closely followed by a metanoia-(a transformative change of heart that triggers remedial action)-can they help India avoid a catastrophic tryst with destiny.

3.
BMJ Nutr Prev Health ; 4(1): 293-306, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34308138

RESUMO

INTRODUCTION: The majority of Indian women have a poor dietary folate and vitamin B12 intake resulting in their chronically low vitamin status, which contributes to anaemia and the high incidence of folate-responsive neural-tube defects (NTDs) in India. Although many countries have successfully deployed centrally-processed folate-fortified flour for prevention of NTDs, inherent logistical problems preclude widespread implementation of this strategy in India. Because tea-the second most common beverage worldwide (after water)-is consumed by most Indians every day, and appeared an ideal vehicle for fortification with folate and vitamin B12, we determined if daily consumption of vitamin-fortified tea for 2 months could benefit young women of childbearing-age in Sangli, India. METHODS: Women (average age=20±2 SD) used teabags spiked with therapeutic doses of 1 mg folate plus either 0.1 mg vitamin B12 (Group-1, n=19) or 0.5 mg vitamin B12 (Group-2, n=19), or mock-fortified teabags (Group-0, n=5) to prepare a cup of tea every day for 2 months, following which their pre-intervention and post-intervention serum vitamin and haemoglobin concentrations were compared. RESULTS: Most women had baseline anaemia with low-normal serum folate and below-normal serum vitamin B12 levels. After 2 months, women in both Group-1 and Group-2 exhibited significant increases in mean differences in pre-intervention versus post-intervention serum folate levels of 8.37 ng/mL (95% CIs 5.69 to 11.04, p<0.05) and 6.69 ng/mL (95% CI 3.93 to 9.44, p<0.05), respectively; however, Group-0 experienced an insignificant rise of 1.26 ng/mL (95% CI -4.08 to 0.16). In addition, over one-half and two-thirds of women in Group-1 and Group-2, respectively, exhibited increases in serum vitamin B12 levels over 300 pg/mL. There was also a significant post-interventional increase in the mean haemoglobin concentration in Group-1 of 1.45 g/dL (95% CI 0.64 to 2.26, p=0.002) and Group-2 of 0.79 g/dL (95% CI 0.11 to 1.42, p=0.027), which reflected a bona fide clinical response. CONCLUSION: Tea is an outstanding scalable vehicle for fortification with folate and vitamin B12 in India, and has potential to help eliminate haematological and neurological complications arising from inadequate dietary consumption or absorption of folate and vitamin B12.

4.
BMJ Case Rep ; 14(2)2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33547097

RESUMO

Iatrogenic iron overload, which is not uncommon in patients undergoing long-term haemodialysis, arises from a combination of multiple red cell transfusions and parenteral iron infusions that are administered to maintain a haemoglobin concentration of approximately 10 g/dL. Although iron overload due to genetic haemochromatosis is conventionally managed by phlebotomy, patients with haemoglobinopathies and chronic transfusion-induced iron overload are treated with iron-chelation therapy. However, the management of iron overload in our patient who presented with hepatic dysfunction and immunosuppressive drug-induced mild anaemia in the post-renal transplant setting posed unique challenges. We report on the decision-making process used in such a case that led to a successful clinical resolution of hepatic iron overload through the combined use of phlebotomy and erythropoiesis stimulating agents, while avoiding use of iron-chelating agents that could potentially compromise both hepatic and renal function.


Assuntos
Sobrecarga de Ferro/etiologia , Sobrecarga de Ferro/terapia , Transplante de Rim , Biópsia , Transfusão de Eritrócitos , Feminino , Hematínicos/administração & dosagem , Humanos , Ferro/administração & dosagem , Sobrecarga de Ferro/diagnóstico , Testes de Função Hepática , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Fatores de Risco
5.
J Nutr ; 148(3): 389-400, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29546304

RESUMO

Background: Epidemiologic and in vitro studies suggest independent linkages between poor folate and/or vitamin B-12 nutrition, genomic human papillomavirus (HPV) type 16 viral integration, and cancer. However, there is no direct evidence in vivo to support the causative role of poor folate nutrition in HPV16 integration into the cellular genome. Objective: We tested the hypothesis that folate deficiency enables the integration of HPV16 into the genome of HPV16-harboring keratinocytes, and could thereby influence earlier transformation of these cells to cancer in an animal model. Methods: HPV16-harboring human keratinocytes [(HPV16)BC-1-Ep/SL] were differentiated into 3-dimensional HPV16-organotypic rafts under either folate-replete or folate-deficient conditions in vitro. These were then subcutaneously implanted in severely immunocompromised female Beige Nude XID (Hsd: NIHS-LystbgFoxn1nuBtkxid) mice (4-6 wk old, 16-18 g) fed either a folate-replete diet (1200 nmol folate/kg diet) or a progressively folate-deficient diet (600 or 400 nmol folate/kg diet) for 2 mo prior to raft-implantation surgery, and indefinitely thereafter. The tumors that subsequently developed were characterized for onset, pattern of growth, morphology, HPV16 oncogene expression, and HPV16-genomic integration. Results: All HPV16-organotypic rafts developed in either folate-replete or physiologic low-folate media in vitro and subsequently implanted in folate-replete mice eventually transformed into aggressive malignancies within weeks. When compared to HPV16-high folate-organotypic raft-derived tumors from mice fed either a 1200 or 600 nmol folate/kg diet, those raft-derived cancers that developed in mice fed a 400 nmol folate/kg diet expressed significantly more HPV16 E6 (1.8-fold more) and E7 (2.8-fold more) oncogenic proteins (P = 0.001), and revealed significantly more HPV16-integration sites in genomic DNA (2-fold more), either directly into, or in the vicinity of, cellular genes (P < 0.05). Conclusions: This unprecedented animal model for the consistent rapid transformation of differentiated (HPV16)BC-1-Ep/SL-derived organotypic raft-keratinocytes to cancer in Beige Nude XID mice confirms that dietary folate deficiency can profoundly influence and modulate events leading to HPV16-induced carcinogenesis, and facilitates genomic integration of HPV16 DNA in vivo.


Assuntos
Carcinogênese/genética , Deficiência de Ácido Fólico/complicações , Ácido Fólico/administração & dosagem , Genoma , Papillomavirus Humano 16/genética , Neoplasias/etiologia , Integração Viral , Animais , DNA , Modelos Animais de Doenças , Feminino , Humanos , Queratinócitos/virologia , Camundongos Nus , Neoplasias/genética , Neoplasias/virologia , Estado Nutricional , Proteínas Oncogênicas Virais/metabolismo , Proteínas E7 de Papillomavirus/metabolismo , Infecções por Papillomavirus/etiologia , Infecções por Papillomavirus/virologia , Proteínas Repressoras/metabolismo , Neoplasias do Colo do Útero
6.
Nutr Rev ; 75(8): 600-615, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28969365

RESUMO

Although a low serum folate concentration is a useful biomarker of pure folate deficiency, the presence of vitamin B12 deficiency or hemolysis or both in individuals with low folate status predictably raises serum folate levels. Therefore, in resource-limited settings where dietary folate deficiency can coexist with vitamin B12 deficiency or malaria or both, the serum folate concentration can range from normal to high, leading to serious underestimation of tissue folate status. This review traces the genesis of an inappropriate overreliance on the serum folate concentration to rule out folate deficiency in vulnerable populations of women and children. Of significance, without due consideration of a chronically inadequate dietary folate intake, authors of influential studies have likely wrongly judged these populations to have an adequate folate status. Through repetition, this error has led to a dangerous entry into the contemporary medical literature that folate deficiency is rare in women and children. As a consequence, many millions of under-resourced women and children with mild to moderate tissue folate deficiency may have been deprived of folate replacement. This review uses historical documents to challenge earlier conclusions and re-emphasizes the need for contextual integration of clinical information in resource-limited settings.


Assuntos
Deficiência de Ácido Fólico/sangue , Deficiência de Vitamina B 12/sangue , Biomarcadores , Países em Desenvolvimento , Dieta , Meio Ambiente , Reações Falso-Negativas , Feminino , Ácido Fólico/administração & dosagem , Ácido Fólico/sangue , Deficiência de Ácido Fólico/complicações , Testes Hematológicos , Humanos , Malária/sangue , Estado Nutricional , Vitamina B 12/sangue , Populações Vulneráveis
7.
J Nutr ; 147(4): 482-498, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28250194

RESUMO

Background: Previously, we determined that heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1) functions as an intracellular physiologic sensor of folate deficiency. In this model, l-homocysteine, which accumulates intracellularly in proportion to the extent of folate deficiency, covalently binds to and thereby activates homocysteinylated hnRNP-E1 to interact with folate receptor-α mRNA; this high-affinity interaction triggers the translational upregulation of cell surface folate receptors, which enables cells to optimize folate uptake from the external milieu. However, integral to this model is the need for ongoing generation of hnRNP-E1 to replenish homocysteinylated hnRNP-E1 that is degraded.Objective: We searched for an interrelated physiologic mechanism that could also maintain the steady-state concentration of hnRNP-E1 during prolonged folate deficiency.Methods: A novel RNA-protein interaction was functionally characterized by using molecular and biochemical approaches in vitro and in vivo.Results: l-homocysteine triggered a dose-dependent high-affinity interaction between hnRNP-E1 and a 25-nucleotide cis element within the 5'-untranslated region of hnRNP-E1 mRNA; this led to a proportionate increase in these RNA-protein complexes, and translation of hnRNP-E1 both in vitro and within placental cells. Targeted perturbation of this RNA-protein interaction either by specific 25-nucleotide antisense oligonucleotides or mutation within this cis element or by small interfering RNA to hnRNP-E1 mRNA significantly reduced cellular biosynthesis of hnRNP-E1. Conversely, transfection of hnRNP-E1 mutant proteins that mimicked homocysteinylated hnRNP-E1 stimulated both cellular hnRNP-E1 and folate receptor biosynthesis. In addition, ferrous sulfate heptahydrate [iron(II)], which also binds hnRNP-E1, significantly perturbed this l-homocysteine-triggered RNA-protein interaction in a dose-dependent manner. Finally, folate deficiency induced dual upregulation of hnRNP-E1 and folate receptors in cultured human cells and tumor xenografts, and more selectively in various fetal tissues of folate-deficient dams.Conclusions: This novel positive feedback loop amplifies hnRNP-E1 during prolonged folate deficiency and thereby maximizes upregulation of folate receptors in order to restore folate homeostasis toward normalcy in placental cells. It will also functionally impact several other mRNAs of the nutrition-sensitive, folate-responsive posttranscriptional RNA operon that is orchestrated by homocysteinylated hnRNP-E1.


Assuntos
Receptor 2 de Folato/metabolismo , Deficiência de Ácido Fólico/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Placenta/citologia , Regulação para Cima/efeitos dos fármacos , Animais , Linhagem Celular , Proteínas de Ligação a DNA , Feminino , Receptor 2 de Folato/genética , Ácido Fólico/farmacologia , Ribonucleoproteínas Nucleares Heterogêneas/genética , Humanos , Camundongos , Camundongos Nus , Neoplasias Experimentais/metabolismo , Gravidez , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA , Neoplasias do Colo do Útero/metabolismo
8.
J Biol Chem ; 287(15): 12559-77, 2012 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-22351779

RESUMO

Although HPV16 transforms infected epithelial tissues to cancer in the presence of several co-factors, there is insufficient molecular evidence that poor nutrition has any such role. Because physiological folate deficiency led to the intracellular homocysteinylation of heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1) and activated a nutrition-sensitive (homocysteine-responsive) posttranscriptional RNA operon that included interaction with HPV16 L2 mRNA, we investigated the functional consequences of folate deficiency on HPV16 in immortalized HPV16-harboring human (BC-1-Ep/SL) keratinocytes and HPV16-organotypic rafts. Although homocysteinylated hnRNP-E1 interacted with HPV16 L2 mRNA cis-element, it also specifically bound another HPV16 57-nucleotide poly(U)-rich cis-element in the early polyadenylation element (upstream of L2L1 genes) with greater affinity. Together, these interactions led to a profound reduction of both L1 and L2 mRNA and proteins without effects on HPV16 E6 and E7 in vitro, and in cultured keratinocyte monolayers and HPV16-low folate-organotypic rafts developed in physiological low folate medium. In addition, HPV16-low folate-organotypic rafts contained fewer HPV16 viral particles, a similar HPV16 DNA viral load, and a much greater extent of integration of HPV16 DNA into genomic DNA when compared with HPV16-high folate-organotypic rafts. Subcutaneous implantation of 18-day old HPV16-low folate-organotypic rafts into folate-replete immunodeficient mice transformed this benign keratinocyte-derived raft tissue into an aggressive HPV16-induced cancer within 12 weeks. Collectively, these studies establish a likely molecular linkage between poor folate nutrition and HPV16 and predict that nutritional folate and/or vitamin-B(12) deficiency, which are both common worldwide, will alter the natural history of HPV16 infections and also warrant serious consideration as reversible co-factors in oncogenic transformation of HPV16-infected tissues to cancer.


Assuntos
Transformação Celular Viral , Deficiência de Ácido Fólico , Papillomavirus Humano 16/fisiologia , Queratinócitos/virologia , Neoplasias Experimentais/virologia , Infecções por Papillomavirus/virologia , Animais , Sequência de Bases , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Catalase/biossíntese , Catalase/genética , Técnicas de Cultura de Células , Proliferação de Células , Células Cultivadas , Proteínas de Ligação a DNA , Feminino , Ácido Fólico/metabolismo , Genes Reporter , Ribonucleoproteínas Nucleares Heterogêneas/química , Ribonucleoproteínas Nucleares Heterogêneas/genética , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Homocisteína/química , Homocisteína/metabolismo , Interações Hospedeiro-Patógeno , Papillomavirus Humano 16/genética , Humanos , Queratinócitos/metabolismo , Queratinócitos/transplante , Camundongos , Camundongos Nus , Dados de Sequência Molecular , Neoplasias Experimentais/patologia , Proteínas Oncogênicas Virais/genética , Proteínas Oncogênicas Virais/metabolismo , Ligação Proteica , Proteólise , RNA Mensageiro/biossíntese , RNA Mensageiro/química , RNA Viral/química , RNA Viral/metabolismo , Proteínas de Ligação a RNA , Compostos de Sulfidrila/metabolismo , Carga Tumoral , Integração Viral
9.
J Biol Chem ; 286(45): 39100-15, 2011 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-21930702

RESUMO

The mechanism underlying the sensing of varying degrees of physiological folate deficiency, prior to adaptive optimization of cellular folate uptake through the translational up-regulation of folate receptors (FR) is unclear. Because homocysteine, which accumulates intracellularly during folate deficiency, stimulated interactions between heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1) and an 18-base FR-α mRNA cis-element that led to increased FR biosynthesis and net up-regulation of FR at cell surfaces, hnRNP-E1 was a plausible candidate sensor of folate deficiency. Accordingly, using purified components, we evaluated the physiological basis whereby L-homocysteine triggered these RNA-protein interactions to stimulate FR biosynthesis. L-homocysteine induced a concentration-dependent increase in RNA-protein binding affinity throughout the range of physiological folate deficiency, which correlated with a proportionate increase in translation of FR in vitro and in cultured human cells. Targeted reduction of newly synthesized hnRNP-E1 proteins by siRNA to hnRNP-E1 mRNA reduced both constitutive and L-homocysteine-induced rates of FR biosynthesis. Furthermore, L-homocysteine covalently bound hnRNP-E1 via multiple protein-cysteine-S-S-homocysteine mixed disulfide bonds within K-homology domains known to interact with mRNA. These data suggest that a concentration-dependent, sequential disruption of critical cysteine-S-S-cysteine bonds by covalently bound L-homocysteine progressively unmasks an underlying RNA-binding pocket in hnRNP-E1 to optimize interaction with FR-α mRNA cis-element preparatory to FR up-regulation. Collectively, such data incriminate hnRNP-E1 as a physiologically relevant, sensitive, cellular sensor of folate deficiency. Because diverse mammalian and viral mRNAs also interact with this RNA-binding domain with functional consequences to their protein expression, homocysteinylated hnRNP-E1 also appears well positioned to orchestrate a novel, nutrition-sensitive (homocysteine-responsive), posttranscriptional RNA operon in folate-deficient cells.


Assuntos
Receptor 1 de Folato/biossíntese , Deficiência de Ácido Fólico/metabolismo , Ácido Fólico/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Homocisteína/metabolismo , Ligação Proteica , Proteínas de Ligação a DNA , Dissulfetos/metabolismo , Receptor 1 de Folato/genética , Deficiência de Ácido Fólico/genética , Células HeLa , Ribonucleoproteínas Nucleares Heterogêneas/genética , Homocisteína/genética , Humanos , Estrutura Terciária de Proteína , RNA Mensageiro , Proteínas de Ligação a RNA , Regulação para Cima
10.
Med Chem ; 7(6): 718-26, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22313312

RESUMO

Nicotinamide adenine dinucleotide (NAD+) is synthesized by the action of nicotinamide mononucleotide adenylyltransferase (NMNAT) from NMN and ATP. The mouse homolog of NMNAT-2 (mmNMNAT-2) was cloned, expressed, and subsequently identified using MALDI-TOF in conjunction with the ProFound database. Circular dichroism analyses of recombinant mmNMNAT-2 showed α helical and ß sheet secondary structures, consistent with the known structure of the human isoform. Competition experiments using mouse pancreatic tissue lysates with recombinant mmNMNAT-2 demonstrated that the activity of the expressed protein was similar to the human isoform. Immunohistochemistry of mouse embryonic tissues with hNMNAT-2 also showed a tissue- and cellular-specific expression of this isoform. Therefore, our studies demonstrate for the first time the clear biological evidence for the existence of a mouse isoform of hNMNAT-2. These studies may help in future investigations aimed at understanding the regulation of this gene and its pathway, and in turn, will spur the development of novel therapies for diseases such as cancer and diabetes since mice are the most frequently used experimental system for in vivo studies.


Assuntos
Clonagem Molecular , Nicotinamida-Nucleotídeo Adenililtransferase/genética , Animais , Dicroísmo Circular , Humanos , Imuno-Histoquímica , Camundongos , NAD/biossíntese , NAD/química , Nicotinamida-Nucleotídeo Adenililtransferase/química , Nicotinamida-Nucleotídeo Adenililtransferase/metabolismo , Estrutura Secundária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
11.
12.
N Engl J Med ; 358(21): 2291; author reply 2291, 2008 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-18504826
14.
Am J Clin Nutr ; 85(2): 598S-603S, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17284762

RESUMO

Despite the isolation of placental folate receptors 25 y ago and progress in defining the mechanism of folate delivery, considerable gaps remain in the literature for each level of the maternal-placental-fetal unit. Although a critical role of placental folate receptors in maternal-to-fetal folate transport was shown by use of the isolated perfused-placental cotyledon model a decade ago, in vivo confirmation is still needed. Knockout of folate receptors in mice, and knock-down of folate receptors by delivery of antisense oligonucleotides at gestation day 8 or antibodies to folate receptor, results in profound developmental abnormalities in the fetus, ranging from neural tube defects to neurocristopathies such as cleft-lip and cleft-palate, cardiac septal defects, and eye defects. These abnormalities can be prevented by ensuring the entry of folate into cells via alternative pathways. Controlled dietary folate restriction studies also identified adverse effects on reproductive performance, implantation, and fetal growth and other subtler (microscopic) defects in murine fetal development. Longitudinal follow-up showed that gestational folate deficiency results in behavioral changes-an anxiety phenotype-during adulthood in these mice, which supports the Barker hypothesis. The extent to which these findings are relevant to humans is unclear, however. Nevertheless, the high incidence of neural tube defects among North Indian women, who chronically subsist on one-third to one-half of the optimum folate needed to prevent birth defects, underscores the magnitude of the public health problem and emphasizes the urgent challenge to define the most efficient way to ensure adequate dietary folate for hundreds of millions of such women at risk in developing countries.


Assuntos
Desenvolvimento Fetal/efeitos dos fármacos , Ácido Fólico/farmacologia , Defeitos do Tubo Neural/prevenção & controle , Animais , Proteínas de Transporte/metabolismo , Feminino , Receptores de Folato com Âncoras de GPI , Ácido Fólico/metabolismo , Deficiência de Ácido Fólico/metabolismo , Humanos , Índia/epidemiologia , Camundongos , Defeitos do Tubo Neural/tratamento farmacológico , Placenta/metabolismo , Gravidez , Receptores de Superfície Celular/metabolismo , Complexo Vitamínico B/farmacologia
15.
Lancet ; 366(9489): 930-1, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16154020

RESUMO

Hospital-based records from major cities of India, where roughly a quarter of the population resides, identified the frequency of neural tube defects (NTDs) as ranging from 3.9 to 8.8 per 1000 births, but the incidence in rural areas is unknown. We did a population-based door-to-door survey of mothers living in remote clusters of villages in Balrampur District in Uttar Pradesh, a region ranked as the least-developed area in India. The data showed that the incidence of NTDs was 6.57-8.21 per 1000 livebirths, which is among the highest worldwide. India's Ministry of Health needs to produce a strategy to reduce the incidence of such defects.


Assuntos
Defeitos do Tubo Neural/epidemiologia , Feminino , Inquéritos Epidemiológicos , Humanos , Incidência , Índia/epidemiologia , Recém-Nascido , Defeitos do Tubo Neural/etiologia , Gravidez , Fatores de Risco , Saúde da População Rural
16.
Birth Defects Res A Clin Mol Teratol ; 73(4): 249-52, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15744731

RESUMO

BACKGROUND: Folate supplementation decreases the incidence of birth defects such as neural tube defects (NTDs). We and others have shown that gestational dietary folate deficiency that does not produce overt NTDs can alter fetal neural histology. Accordingly, murine offspring were examined for the possible functional consequences of prenatal folate deficiency. METHODS: CD-1 mice were fed a diet of chow containing 400, 600, or 1200 nmol of folic acid/kg of chow for eight weeks prior to breeding and until GD18, at which time all dams were placed on folate-replete chow. Behavioral tests of male and female offspring included righting reflex, negative geotaxis, forelimb hanging, motor coordination, open field activity, and elevated plus maze activity. RESULTS: Of greatest significance, the adult offspring that were prenatally folate-deficient exhibited more anxiety-related behavior in the elevated plus maze. Offspring of the 400 nmol of folic acid/kg of chow diet group exhibited significantly shorter durations in the open arms and longer durations in the closed arms. Further, these two behaviors were dose-related. There was also a trend for the prenatally folate-deficient adult mice to exhibit more thigmotaxis (wall-hugging) behavior in the open field, entering the central area less frequently than controls. There were few other differences in tested behaviors between folate-deficient and folate-replete mice. CONCLUSIONS: Prenatal folate deficiency that is repleted at birth can manifest later with increased anxiety 9-12 weeks after birth.


Assuntos
Ansiedade/fisiopatologia , Comportamento Animal , Deficiência de Ácido Fólico/fisiopatologia , Animais , Comportamento Animal/efeitos dos fármacos , Dieta , Feminino , Ácido Fólico/farmacologia , Masculino , Camundongos , Gravidez
17.
Artigo em Inglês | MEDLINE | ID: mdl-15641086

RESUMO

BACKGROUND: Homocysteine, which increases in folate deficiency, can upregulate folate receptors (FR) at the translational level by increasing the interaction between a short cis-element in the 5'-untranslated region of FR-alpha mRNA and heterogeneous nuclear ribonucleoprotein-E1 (hnRNP-E1). Perturbation of this RNA-protein interaction on GD8.5 induces neural tube defects and neurocristopathies in mice. FR upregulation can also reduce cell proliferation independently of folate deficiency in some human cells. Accordingly, we tested the hypothesis that sustained murine maternal folate deficiency would negatively impact pregnancy outcomes, upregulate FR, and selectively reduce fetal cell proliferation. METHODS: Dams were fed chow with various levels of folic acid added for eight weeks before and throughout pregnancy. Following sacrifice on GD17, dams were compared for folate and homocysteine status as well as pregnancy outcomes. Fetuses from some groups were evaluated by specific biochemical, molecular, and immunohistochemical studies for FR, hnRNP-E1, and apoptosis. RESULTS: When compared to dams fed a folate-replete diet, those dams on a folate-depleted diet developed reduced red cell folates and hyperhomocysteinemia and an inverse dose-dependent upregulation of FR and hnRNP-E1 on GD17 without alterations in cell number in the majority of tissues. However, FR overexpression was accompanied by a significant reduction in the net number of cells in the midgut, lung, pons, tongue, and olfactory epithelium, and with premature differentiation in dorsal root ganglion cells and dysplasia of taste buds. By contrast, in the brain, spinal cord, diaphragm, and primordium of follicles of vibrissae, there was less FR expression, which accompanied a net reduction in number of cells and architectural anomalies. Subtle "immunohistochemical footprints" of apoptosis on GD17 fetuses corresponded with net cell loss in the lung and olfactory epithelium. Upregulation of FR could be explained by a homocysteine-induced RNA-protein interaction in folate-depleted fetuses that led to a proportionate increase in murine FR biosynthesis. CONCLUSIONS: Maternal folate deficiency results in selective upregulation of FR and hnRNP-E1 associated with multiple aberrations in fetal tissues that include increased cell loss, architectural anomalies, and premature differentiation. The potential significance of these findings to explain the wide spectrum of folate-responsive birth defects in humans is discussed.


Assuntos
Proteínas de Transporte/metabolismo , Feto/patologia , Ácido Fólico/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Receptores de Superfície Celular/metabolismo , Animais , Diferenciação Celular/fisiologia , Eletroforese em Gel de Poliacrilamida , Ensaio de Desvio de Mobilidade Eletroforética , Feminino , Receptores de Folato com Âncoras de GPI , Imuno-Histoquímica , Fígado/metabolismo , Camundongos , Gravidez , Regulação para Cima , Vitamina B 12/metabolismo
18.
Anal Biochem ; 332(1): 168-77, 2004 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-15301962

RESUMO

Cell membrane-associated folate receptors are selectively overexpressed in certain human tumors. The high affinity of folic acid for folate receptors provides a unique opportunity to use folic acid as a targeting ligand to deliver chemotherapeutic agents to cancer cells. Folate-tethered liposomes bearing pteroyl-gamma-glutamate-cysteine-polyethylene glycol (PEG)-distearoylphosphatidylethanolamine (DSPE) as the targeting component are under investigation as mediators of drug and gene delivery to cancer cells that overexpress folate receptors. Pteroyl-gamma-glutamate-cysteine synthesis is one of the crucial starting steps in the preparation of pteroyl-gamma-glutamate-cysteine-PEG-DSPE. However, published methods for the synthesis of pteroyl-gamma-glutamate-cysteine provide low yields and are not easily reproducible. Therefore, we developed a modified synthetic method for the removal of the N(10)-trifluoroacetyl group after cleavage/deprotection that is reliable, is easily reproducible, and has high yield (38%) compared with an unreliable yield of 3-20% with the earlier methods. Folate-tethered liposomes containing calcein or doxorubicin were prepared using pteroyl-gamma-glutamate-cysteine-PEG-DSPE as the targeting component along with nontargeted liposomes with PEG-DSPE. The results of the uptake of calcein and cytotoxicity of doxorubicin in human cervical cancer HeLa-IU(1) cells and human colon cancer Caco-2 cells demonstrated that folate-tethered liposomes were efficient in selective delivery to cancer cells overexpressing folate receptors. The improvement in yield of the targeting component can significantly facilitate "scale up" of folate receptor-mediated liposomal cancer therapy to the preclinical and clinical levels of investigations.


Assuntos
Proteínas de Transporte/metabolismo , Cisteína/metabolismo , Ácido Fólico/metabolismo , Lipossomos/metabolismo , Neoplasias/metabolismo , Receptores de Superfície Celular/metabolismo , Células CACO-2 , Cromatografia Líquida de Alta Pressão , Doxorrubicina/metabolismo , Fluoresceínas/metabolismo , Receptores de Folato com Âncoras de GPI , Humanos , Fosfatidiletanolaminas/metabolismo , Polietilenoglicóis/metabolismo
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