ABSTRACT
Previous studies have shown that low platelet count combined with high plasma total homocysteine (tHcy) increased stroke risk and can be lowered by 73% with folic acid. However, the combined role of other platelet activation parameters and the methylenetetrahydrofolate reductase (MTHFR) C677T genotypes on stroke risk and folic acid treatment benefit remain to be examined. This study aimed to investigate if platelet activation parameters and MTHFR genotypes jointly impact folic acid treatment efficacy in first stroke prevention. Data were derived from the China Stroke Primary Prevention Trial. This study includes a total of 11,185 adult hypertensive patients with relevant platelet activation parameters and MTHFR genotype data. When simultaneously considering both platelet activation parameters (plateletcrit, platelet count, mean platelet volume, platelet distribution width) and MTHFR genotypes, patients with both low plateletcrit (Q1) and the TT genotype had the highest stroke incidence rate (5.6%) in the enalapril group. This subgroup significantly benefited from folic acid treatment, with a 66% reduction in first stroke (HR: 0.34; 95% CI: 0.14-0.82; p = 0.016). Consistently, the subgroup with low plateletcrit (Q1) and the CC/CT genotype also benefited from folic acid treatment (HR: 0.40; 95% CI: 0.23-0.70; p = 0.001). In Chinese hypertensive adults, low plateletcrit can identify those who may greatly benefit from folic acid treatment, in particular, those with the TT genotype, a subpopulation known to have the highest stroke risk.
Subject(s)
Folic Acid , Genotype , Methylenetetrahydrofolate Reductase (NADPH2) , Stroke , Humans , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Folic Acid/administration & dosage , Folic Acid/genetics , Stroke/genetics , Stroke/prevention & control , Male , Female , Middle Aged , Aged , Hypertension/genetics , Platelet Activation/genetics , Platelet Activation/drug effects , China/epidemiology , Blood Platelets/metabolism , Blood Platelets/drug effects , Platelet Count , AdultABSTRACT
A number of essential nutrients are involved in the folate cycle, and its effectiveness depends on the sufficient intake of them. In addition, polymorphic variants of the methylenetetrahydrofolate reductase (MTHFR), methionine synthase reductase (MTRR) and methionine synthase (MTR) genes affect a wide range of biochemical reactions of the folate cycle and should also be considered as a risk factor for the development of a number of diseases. The purpose of this research was to study the prevalence of these risk factors. Material and methods. The prevalence of polymorphisms of the folate cycle genes: C677T polymorphism of the MTHFR gene and A66G polymorphism of the MTRR gene in a random stratified (by sex and age) sample of the adult population of the Omsk region [n=139, 51 men, 88 women, aged 18 to 75 years, median age 37 (26; 48) years] was studied. The identification of polymorphisms was carried out by the method of allele-specific polymerase chain reaction with an electrophoretic detection scheme. Using the food intake frequency questionnaire, the dietary intake of nutrients involved in the folate cycle was determined: B vitamins (B6, B2, B9, B12), methionine, choline, in a representative stratified sample of residents of the Omsk region [n=421, 177 men, 244 women, aged 18 to 83 years, median age 37 (23; 57) years]. Results. MTHFR genotypes (A222V С677T C>T) were distributed as follows: CC-type - 51.3%, CT - 41.0%, TT - 7.7%; MTRR genotypes (I22M A>G): AA type - 57.9%, AG - 30.3%, GG - 11.8%. The analysis of actual nutrition showed consumption below the recommended dietary intake of folates in 88.2% persons, vitamin B2 and choline - in 40.5%, vitamin B6 - in 29.2%, methionine - in 22.0%. Vitamin B12 intake was within the recommended range. Conclusion. The totality of the data presented indicates the combined influence and wide distribution of factors that determine the low efficiency of the folate cycle, and, as a result, a high risk of developing a characteristic pathology for the adult population of the region, which determines the need and priorities for prevention measures, including healthy nutrition.
Subject(s)
Folic Acid , Polymorphism, Genetic , Adult , Male , Humans , Female , Folic Acid/genetics , Genotype , Methionine , Choline , Case-Control StudiesABSTRACT
This study aimed to explore the mediation effects of one-carbon metabolism (OCM) related nutrients on the association between MTHFR rs1801133 polymorphism and gestational diabetes mellitus (GDM). Folate, vitamin B12 and homocysteine (Hcy) were measured in the serum of 1254 pregnant women. Linear and logistic regressions were used to estimate the associations of OCM nutrients and MTHFR rs1801133 polymorphism with blood glucose levels and GDM risk. Mediation analysis was applied to test the mediation effects of folate, vitamin B12 and Hcy on the association of MTHFR rs1801133 polymorphism with blood glucose concentrations and GDM. Pregnant women with MTHFR rs1801133 CC genotype had higher serum folate (10·75 v. 8·90 and 9·40 ng/ml) and lower serum Hcy (4·84 v. 4·93 and 5·20 µmol/l) than those with CT and TT genotypes. Folate concentrations were positively associated with fasting plasma glucose (FPG), 1-h plasma glucose (1-h PG), 2-h plasma glucose (2-h PG) and GDM risk. Vitamin B12 levels were negatively correlated with FPG and GDM. Although no direct association was found between MTHFR rs1801133 genotypes and GDM, there were significant indirect effects of MTHFR rs1801133 CC genotype on FPG (ß: 0·005; 95 % CI: 0·001, 0·013), 1-h PG (ß: 0·006; 95 % CI: 0·001, 0·014), 2-h PG (ß: 0·007; 95 % CI: 0·001, 0·015) and GDM (ß: 0·006; 95 % CI: 0·001, 0·014) via folate. In conclusion, serum folate mediates the effect of MTHFR rs1801133 on blood glucose levels and GDM. Our findings potentially provide a feasible GDM prevention strategy via individualised folate supplementation according to the MTHFR genotypes.
Subject(s)
Diabetes, Gestational , Folic Acid , Female , Humans , Pregnancy , Blood Glucose/analysis , Diabetes, Gestational/blood , Diabetes, Gestational/genetics , East Asian People , Folic Acid/genetics , Genotype , Homocysteine , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Vitamin B 12 , VitaminsABSTRACT
Insufficient dietary folate intake, hereditary malabsorption, or defects in folate transport may lead to combined immunodeficiency (CID). Although loss of function mutations in the major intestinal folate transporter PCFT/SLC46A1 was shown to be associated with CID, the evidence for pathogenic variants of RFC/SLC19A1 resulting in immunodeficiency was lacking. We report two cousins carrying a homozygous pathogenic variant c.1042 G > A, resulting in p.G348R substitution who showed symptoms of immunodeficiency associated with defects of folate transport. SLC19A1 expression by peripheral blood mononuclear cells (PBMC) was quantified by real-time qPCR and immunostaining. T cell proliferation, methotrexate resistance, NK cell cytotoxicity, Treg cells and cytokine production by T cells were examined by flow cytometric assays. Patients were treated with and benefited from folinic acid. Studies revealed normal NK cell cytotoxicity, Treg cell counts, and naive-memory T cell percentages. Although SLC19A1 mRNA and protein expression were unaltered, remarkably, mitogen induced-T cell proliferation was significantly reduced at suboptimal folic acid and supraoptimal folinic acid concentrations. In addition, patients' PBMCs were resistant to methotrexate-induced apoptosis supporting a functionally defective SLC19A1. This study presents the second pathogenic SLC19A1 variant in the literature, providing the first experimental evidence that functionally defective variants of SLC19A1 may present with symptoms of immunodeficiency.
Subject(s)
Immunologic Deficiency Syndromes , Leucovorin , Reduced Folate Carrier Protein , Humans , Folic Acid/genetics , Folic Acid/metabolism , Leucovorin/therapeutic use , Leucovorin/metabolism , Leukocytes, Mononuclear/metabolism , Methotrexate/pharmacology , Methotrexate/therapeutic use , Proton-Coupled Folate Transporter/genetics , Proton-Coupled Folate Transporter/metabolism , Reduced Folate Carrier Protein/genetics , Immunologic Deficiency Syndromes/drug therapy , Immunologic Deficiency Syndromes/genetics , Immunologic Deficiency Syndromes/metabolismABSTRACT
BACKGROUND: Folate has a pivotal role in maintaining different cellular processes including DNA integrity and neurotransmitter levels. Further, folate deficiency was reported in subjects with neuropsychiatric disorders including autism spectrum disorder (ASD). METHODS AND RESULTS: We recruited ASD probands following the Diagnostic and Statistical Manual of Mental Disorder-IV/-5. Severity was assessed by the Childhood Autism Rating Scale2-Standard Test (CARS2-ST). Functional SNPs in reduced folate carrier1 (rs1051266), methylenetetrahydrofolate dehydrogenase (rs2236225), methylenetetrahydrofolate methyltransferase (rs1805087), methylenetetrahydrofolate reductase (rs1801133 and rs1801131), cystathionine-beta- synthase (rs5742905), and serine hydroxymethyltransferase (rs1979277) genes were analyzed in the ASD probands (N = 203), their parents and controls (N = 250) by PCR/TaqMan based methods. Plasma homocysteine and vitamin B12 levels were examined by Enzyme-Linked ImmunoSorbent Assay. Statistical analysis revealed higher frequencies of rs1051266 and rs1805087 "A" alleles (P = 8.233e-005 and P = 0.010 respectively) and rs1051266 "AA" genotype (P = 0.02) in the ASD probands. Gender based stratified analysis revealed higher frequency of rs1051266 "AA" in the male probands (P = 0.001) while frequencies of rs1805087 "A" (P = 0.001) and "AA" (P < 0.05), and rs2236225 "CC" (P = 0.03) were higher in the females. The case-control analysis also exhibited a significant difference in the occurrence of biallelic and triallelic haplotypes. rs1051266 "A", rs1979277 "T" and rs5742905 "C" alleles showed biased parental transmission (P = 0.02). CARS2-ST scores were higher in the presence of rs5742905 "T" while scores were lower in the presence of rs1979277 "T" and rs1051266 "A". ASD probands showed vitamin B12 deficiency. CONCLUSION: Based on these observations, we infer that components needed for proper folate metabolism may influence ASD severity in this population.
Subject(s)
Autism Spectrum Disorder/metabolism , Folic Acid/metabolism , Alleles , Asian People/genetics , Autism Spectrum Disorder/genetics , Case-Control Studies , Cystathionine beta-Synthase/genetics , Folic Acid/genetics , Gene Frequency/genetics , Genetic Predisposition to Disease/genetics , Genotype , Glycine Hydroxymethyltransferase/genetics , Haplotypes/genetics , Humans , India/epidemiology , Metabolic Networks and Pathways/genetics , Methylenetetrahydrofolate Dehydrogenase (NADP)/genetics , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Polymorphism, Single Nucleotide/geneticsABSTRACT
With the aging population and increasing life expectancy, Parkinson's disease (PD), a neurological disorder rapidly increasing in morbidity and mortality, is causing a huge burden on society and the economy. Several studies have suggested that one-carbon metabolites, including homocysteine, vitamin B6, vitamin B12 and folate acid, are associated with PD risk. However, the results remain inconsistent and controversial. Thus, we performed a two-sample Mendelian randomization (MR) study to detect the causality between one-carbon metabolites and PD susceptibility as well as age at PD onset. We collected several genetic variants as instrumental variables from large genome-wide association studies of one-carbon metabolites (homocysteine: N = 14, vitamin B6: N = 1, vitamin B12: N = 10, folate acid: N = 2). We then conducted MR analyses using the inverse variance-weighted (IVW) approach and additional MR-Egger regression, weighted median and MR-pleiotropy residual sum and outlier (MR-PRESSO) methods to further test causality. The results showed no causal association between circulating homocysteine levels and PD risk (p = 0.868) or age at PD onset (p = 0.222) with the IVW method. Meanwhile, similar results were obtained by three complementary analyses. In addition, we did not observe any evidence that the circulating levels of vitamin B6, vitamin B12 and folate acid affected the risk of PD or age at onset of PD. Our findings implied that lowering homocysteine levels through vitamin B6, vitamin B12 or folate acid supplementation may not be clinically helpful in preventing PD or delaying the age at PD onset.
Subject(s)
Folic Acid/genetics , Folic Acid/metabolism , Homocysteine/genetics , Homocysteine/metabolism , Mendelian Randomization Analysis/methods , Negative Results , Parkinson Disease/etiology , Parkinson Disease/metabolism , Vitamin B 12/genetics , Vitamin B 12/metabolism , Vitamin B 6/genetics , Vitamin B 6/metabolism , Age of Onset , Dietary Supplements , Disease Susceptibility , Genome-Wide Association Study , Parkinson Disease/prevention & control , RiskABSTRACT
Congenital heart defects (CHD) affect 50% of Down's syndrome (DS) cases. This review focusses on the pathogenic molecular mechanism leading to the formation of DS-associated CHD along with the advancement of the emerging diagnostic techniques available for such patients in past few decades. We have shed light on the causative genes of DS-associated CHD that are located either on chromosome 21 or outside chromosome 21. Along with locus-specific mutation, numerous SNP and CNV, miRNA, use of maternal folic acid during pregnancy and signalling pathways are also reported to contribute to the formation of CHD in patients with DS. With the help of both these our understanding of pathogenic mechanism causing CHD in DS cases along with the availability of emerging technologies has facilitated a novel discovery that has ultimately provided a better treatment and management for such cases. Accurate diagnosis and treatment are now available with the introduction of CNV detection and NGS based approaches such as WES, WGS, target sequencing and sequencing of foetal cell-free DNA by the medical geneticist and cardiologist have now allowed further identification of familial recurrence risk and relatives who are at risk through genetic counselling, thereby providing reproductive options and improving proper care of DS-associated CHD. Further, gene-editing studies explore novel pathogenic mechanisms and signalling pathways in DS-associated CHD.
Subject(s)
Down Syndrome/diagnosis , Genetic Counseling , Heart Defects, Congenital/diagnosis , Down Syndrome/complications , Down Syndrome/genetics , Down Syndrome/pathology , Female , Folic Acid/genetics , Folic Acid/metabolism , Heart Defects, Congenital/complications , Heart Defects, Congenital/genetics , Humans , MicroRNAs/genetics , PregnancyABSTRACT
The agouti viable yellow (Avy) allele is an insertional mutation in the mouse genome caused by a variably methylated intracisternal A particle (VM-IAP) retrotransposon. Avy expressivity is sensitive to a range of early-life chemical exposures and nutritional interventions, suggesting that environmental perturbations can have long-lasting effects on the methylome. However, the extent to which VM-IAP elements are environmentally labile with phenotypic implications is unknown. Using a recently identified repertoire of VM-IAPs, we assessed the epigenetic effects of different environmental contexts. A longitudinal aging analysis indicated that VM-IAPs are stable across the murine lifespan, with only small increases in DNA methylation detected for a subset of loci. No significant effects were observed after maternal exposure to the endocrine disruptor bisphenol A, an obesogenic diet or methyl donor supplementation. A genetic mouse model of abnormal folate metabolism exhibited shifted VM-IAP methylation levels and altered VM-IAP-associated gene expression, yet these effects are likely largely driven by differential targeting by polymorphic KRAB zinc finger proteins. We conclude that epigenetic variability at retrotransposons is not predictive of environmental susceptibility.
Subject(s)
DNA Methylation , Endocrine Disruptors/toxicity , Obesity/genetics , Retroelements , Animals , Benzhydryl Compounds/toxicity , DNA Methylation/drug effects , Diet/adverse effects , Epigenesis, Genetic , Female , Ferredoxin-NADP Reductase/genetics , Folic Acid/genetics , Folic Acid/metabolism , Folic Acid Deficiency/genetics , Gene Expression Regulation , Male , Mice, Inbred C57BL , Mice, Mutant Strains , Mutation , Obesity/etiology , Phenols/toxicity , Pregnancy , Prenatal Exposure Delayed EffectsABSTRACT
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition affecting behavior and communication, presenting with extremely different clinical phenotypes and features. ASD etiology is composite and multifaceted with several causes and risk factors responsible for different individual disease pathophysiological processes and clinical phenotypes. From a genetic and epigenetic side, several candidate genes have been reported as potentially linked to ASD, which can be detected in about 10-25% of patients. Folate gene polymorphisms have been previously associated with other psychiatric and neurodegenerative diseases, mainly focused on gene variants in the DHFR gene (5q14.1; rs70991108, 19bp ins/del), MTHFR gene (1p36.22; rs1801133, C677T and rs1801131, A1298C), and CBS gene (21q22.3; rs876657421, 844ins68). Of note, their roles have been scarcely investigated from a sex/gender viewpoint, though ASD is characterized by a strong sex gap in onset-risk and progression. The aim of the present review is to point out the molecular mechanisms related to intracellular folate recycling affecting in turn remethylation and transsulfuration pathways having potential effects on ASD. Brain epigenome during fetal life necessarily reflects the sex-dependent different imprint of the genome-environment interactions which effects are difficult to decrypt. We here will focus on the DHFR, MTHFR and CBS gene-triad by dissecting their roles in a sex-oriented view, primarily to bring new perspectives in ASD epigenetics.
Subject(s)
Autism Spectrum Disorder/genetics , Brain/metabolism , Epigenome , Folic Acid/metabolism , Methionine/metabolism , Animals , Autism Spectrum Disorder/metabolism , Female , Folic Acid/genetics , Humans , Male , Methionine/genetics , Polymorphism, Single Nucleotide , Sex FactorsABSTRACT
BACKGROUND: The folate metabolism that converts homocysteine to methionine is closely related to the accumulation of homocysteine. Increased homocysteine levels lead to an impaired antithrombotic function of the vascular endothelium and uterine-placental circulation, resulting in abnormal pregnancy outcomes. Previous studies have reported that gene polymorphisms in folate metabolism are associated with the development of preterm birth (PTB) in various populations. OBJECTIVE: we performed a case-control study to evaluate the association between five polymorphisms in folate metabolic genes (MTHFR, MTR, MTRR, TCN2) and PTB. METHODS: In this study, a total of 254 subjects were analyzed (111 patients with PTB and 143 women at ≥ 38 weeks of gestation). Genotype and allele frequency differences between patients and control groups and the Hardy-Weinberg equilibrium were assessed using a Chi-square test. For evaluation indicators, odds ratios (ORs) of 95% confidence intervals (CI) were estimated. In addition, we analyzed the combined genotype frequencies of SNPs of folate-metabolizing genes to measure gene-gene interactions for PTB. RESULTS: Our results showed that the MTR rs1805087 GG (p = 0.031), and TCN2 rs1801198 CG genotype (OR 0.53, 95% CI 0.288-0.980, p = 0.042) were significantly associated with PTB. The MTHFR rs4846049 AA showed a marginal trend toward significance (OR 0.15, 95% CI 0.018-1.205, p = 0.041). In particular, the combined genotypes, including MTHFR rs1537514 CC-MTRR rs1801394 GG, MTHFR rs1537514 CC-TCN2 rs1801198 CG, and MTR rs1805087 AA-TCN2 rs1801198 CG, have significant interactions with PTB (OR 0.49, 95% CI 0.248-0.992, p < 0.05). CONCLUSION: The polymorphisms of folate metabolic genes may have a genetic association with the development of PTB in Korean women. A larger sample set and functional studies are required to further elucidate our findings.
Subject(s)
5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase/genetics , Genetic Predisposition to Disease , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Premature Birth/genetics , Transcobalamins/genetics , Alleles , Female , Ferredoxin-NADP Reductase/genetics , Folic Acid/genetics , Folic Acid/metabolism , Gene Frequency , Genetic Association Studies , Genotype , Humans , Infant, Newborn , Placenta/metabolism , Placenta/pathology , Polymorphism, Single Nucleotide/genetics , Polypyrimidine Tract-Binding Protein/genetics , Pregnancy , Premature Birth/epidemiology , Premature Birth/metabolism , Premature Birth/pathology , Republic of Korea/epidemiologyABSTRACT
Moderate folic acid (FA) intake is an effective strategy that slows colorectal cancer (CRC) progression. However, high consumption of FA may trigger the transition of precancerous tissue towards malignancy. MicroRNAs (miRNAs) are considered to be potential biomarkers of CRC. Thus, identification of miRNAs of dysregulated genes in CRC cells by detailed analysis of mRNA and miRNA expression profile in the context of FA deficiency could substantially increase our understanding of its oncogenesis. mRNA-seq and miRNA-seq analyses were utilized to investigate the expression of miRNAs in FA-deficient CRC cell line-HCT116 through massive parallel sequencing technology. A total of 38 mRNAs and 168 miRNAs were identified to be differentially expressed between CRC groups with or without FA deficiency. We constructed an miRNA-mRNA network for the vital regulatory miRNAs altered in FA-deficient CRC cells. The mRNAs and miRNAs validated by Western blotting and RT-qPCR were consistent with the sequencing results. Results showed that FA deficiency upregulated some miRNAs thereby inhibiting the expression of critical genes in the endoplasmic reticulum (ER) stress pathway. Dysregulated miRNAs in our miRNA-mRNA network could contribute to CRC cell in response to deficient FA. This work reveals novel molecular targets that are likely to provide therapeutic interventions for CRC.
Subject(s)
Endoplasmic Reticulum Stress/genetics , Folic Acid Deficiency/genetics , Gene Regulatory Networks/genetics , MicroRNAs/genetics , RNA, Messenger/genetics , Apoptosis/genetics , Cell Proliferation/genetics , Folic Acid/genetics , Folic Acid/metabolism , HCT116 Cells , High-Throughput Nucleotide Sequencing , Humans , MicroRNAs/metabolism , Protein Interaction Maps/genetics , RNA, Messenger/metabolism , TranscriptomeABSTRACT
BACKGROUND: Folate, vitamin B6 and vitamin B12 have been associated with digestive system cancers. We conducted a two-sample Mendelian randomisation study to assess the causality of these associations. METHODS: Two, one and 14 independent single nucleotide polymorphisms associated with serum folate, vitamin B6 and vitamin B12 at the genome-wide significance threshold were selected as genetic instruments. Summary-level data for the associations of the vitamin-associated genetic variants with cancer were obtained from the UK Biobank study including 367,561 individuals and FinnGen consortium comprising up to 176,899 participants. RESULTS: Genetically predicted folate and vitamin B6 concentrations were not associated with overall cancer, overall digestive system cancer or oesophageal, gastric, colorectal or pancreatic cancer. Genetically predicted vitamin B12 concentrations were positively associated with overall digestive system cancer (ORSD, 1.12; 95% CI 1.04, 1.21, p = 0.003) and colorectal cancer (ORSD 1.16; 95% CI 1.06, 1.26, p = 0.001) in UK Biobank. Results for colorectal cancer were consistent in FinnGen and the combined ORSD was 1.16 (95% CI 1.08, 1.25, p < 0.001). There was no association of genetically predicted vitamin B12 with any other site-specific digestive system cancers or overall cancer. CONCLUSIONS: These results provide evidence to suggest that elevated serum vitamin B12 concentrations are associated with colorectal cancer.
Subject(s)
Digestive System Neoplasms/blood , Digestive System Neoplasms/epidemiology , Polymorphism, Single Nucleotide , Vitamin B Complex/blood , Adult , Anemia, Pernicious/blood , Anemia, Pernicious/epidemiology , Anemia, Pernicious/genetics , Case-Control Studies , Digestive System Neoplasms/diagnosis , Digestive System Neoplasms/genetics , Female , Folic Acid/blood , Folic Acid/genetics , Genetic Association Studies , Genetic Predisposition to Disease , Genetic Testing , Humans , Male , Mendelian Randomization Analysis , Risk Factors , Sweden/epidemiology , United Kingdom/epidemiology , Vitamin B 12/blood , Vitamin B 12/genetics , Vitamin B 6/blood , Vitamin B 6/genetics , Vitamin B Complex/genetics , Vitamin B Deficiency/blood , Vitamin B Deficiency/epidemiology , Vitamin B Deficiency/geneticsABSTRACT
Genetic analysis of brown midrib sorghum (Sorghum bicolor) mutant lines assembled in our program has previously shown that the mutations fall into four allelic groups, bmr2, bmr6, bmr12 or bmr19. Causal genes for allelic groups bmr2, bmr6 and bmr12, have since been identified. In this report, we provide evidence for the nature of the bmr19 mutation. This was accomplished by introgressing each of the four bmr alleles into nine different genetic backgrounds. Polymorphisms from four resequenced bulks of sorghum introgression lines containing either mutation, relative to those of a resequenced bulk of the nine normal midrib recurrent parent lines, were used to locate their respective causal mutations. The analysis confirmed the previously reported causal mutations for bmr2 and bmr6 but failed in the case of bmr12-bulk due to a mixture of mutant alleles at the locus among members of that mutant bulk. In the bmr19-bulk, a common G â A mutation was found among all members in Sobic.001G535500. This gene encodes a putative folylpolyglutamate synthase with high homology to maize Bm4. The brown midrib phenotype co-segregated with this point mutation in two separate F2 populations. Furthermore, an additional variant allele at this locus obtained from a TILLING population also showed a brown midrib phenotype, confirming this locus as Bmr19.
Subject(s)
Folic Acid/metabolism , Lignin/biosynthesis , Peptide Synthases/genetics , Plant Proteins/genetics , Sorghum/genetics , Folic Acid/genetics , Genetic Background , Lignin/genetics , Peptide Synthases/metabolism , Plant Proteins/metabolism , Polymorphism, Single Nucleotide , Sorghum/metabolismABSTRACT
There are three major folate uptake systems in human tissues and tumors, including the reduced folate carrier (RFC), folate receptors (FRs) and proton-coupled folate transporter (PCFT). We studied the functional interrelationships among these systems for the novel tumor-targeted antifolates AGF94 (transported by PCFT and FRs but not RFC) and AGF102 (selective for FRs) versus the classic antifolates pemetrexed, methotrexate and PT523 (variously transported by FRs, PCFT and RFC). We engineered HeLa cell models to express FRα or RFC under control of a tetracycline-inducible promoter with or without constitutive PCFT. We showed that cellular accumulations of extracellular folates were determined by the type and levels of the major folate transporters, with PCFT and RFC prevailing over FRα, depending on expression levels and pH. Based on patterns of cell proliferation in the presence of the inhibitors, we established transport redundancy for RFC and PCFT in pemetrexed uptake, and for PCFT and FRα in AGF94 uptake; uptake by PCFT predominated for pemetrexed and FRα for AGF94. For methotrexate and PT523, uptake by RFC predominated even in the presence of PCFT or FRα. For both classic (methotrexate, PT523) and FRα-targeted (AGF102) antifolates, anti-proliferative activities were antagonized by PCFT, likely due to its robust activity in mediating folate accumulation. Collectively, our findings describe a previously unrecognized interplay among the major folate transport systems that depends on transporter levels and extracellular pH, and that determines their contributions to the uptake and anti-tumor efficacies of targeted and untargeted antifolates.
Subject(s)
Folate Receptor 1/genetics , Folic Acid/metabolism , Neoplasms/drug therapy , Proton-Coupled Folate Transporter/genetics , Reduced Folate Carrier Protein/genetics , Biological Transport/genetics , Cell Proliferation/drug effects , Folate Receptor 1/metabolism , Folic Acid/genetics , Folic Acid Antagonists/pharmacology , HeLa Cells , Humans , Methotrexate/pharmacology , Neoplasms/genetics , Neoplasms/metabolism , Ornithine/analogs & derivatives , Ornithine/pharmacology , Pemetrexed/pharmacology , Proton-Coupled Folate Transporter/metabolism , Pterins/pharmacology , Reduced Folate Carrier Protein/metabolismABSTRACT
Most of the drugs currently prescribed for cancer treatment are riddled with substantial side effects. In order to develop more effective and specific strategies to treat cancer, it is of importance to understand the biology of drug targets, particularly the newly emerging ones. A comprehensive evaluation of these targets will benefit drug development with increased likelihood for success in clinical trials. The folate-mediated one-carbon (1C) metabolism pathway has drawn renewed attention as it is often hyperactivated in cancer and inhibition of this pathway displays promise in developing anticancer treatment with fewer side effects. Here, we systematically review individual enzymes in the 1C pathway and their compartmentalization to mitochondria and cytosol. Based on these insight, we conclude that (1) except the known 1C targets (DHFR, GART, and TYMS), MTHFD2 emerges as good drug target, especially for treating hematopoietic cancers such as CLL, AML, and T-cell lymphoma; (2) SHMT2 and MTHFD1L are potential drug targets; and (3) MTHFD2L and ALDH1L2 should not be considered as drug targets. We highlight MTHFD2 as an excellent therapeutic target and SHMT2 as a complementary target based on structural/biochemical considerations and up-to-date inhibitor development, which underscores the perspectives of their therapeutic potential.
Subject(s)
Lymphoma, T-Cell/drug therapy , Metabolic Networks and Pathways/drug effects , Mitochondria/drug effects , Neoplasms/drug therapy , Carbon/metabolism , Folic Acid/genetics , Folic Acid/metabolism , Humans , Lymphoma, T-Cell/metabolism , Lymphoma, T-Cell/pathology , Mitochondria/genetics , Mitochondria/metabolism , Neoplasms/metabolismABSTRACT
Folate metabolism supplies one-carbon (1C) units for biosynthesis and methylation and has long been a target for cancer chemotherapy. Mitochondrial serine catabolism is considered the sole contributor of folate-mediated 1C units in proliferating cancer cells. Here, we show that under physiological folate levels in the cell environment, cytosolic serine-hydroxymethyltransferase (SHMT1) is the predominant source of 1C units in a variety of cancers, while mitochondrial 1C flux is overly repressed. Tumor-specific reliance on cytosolic 1C flux is associated with poor capacity to retain intracellular folates, which is determined by the expression of SLC19A1, which encodes the reduced folate carrier (RFC). We show that silencing SHMT1 in cells with low RFC expression impairs pyrimidine biosynthesis and tumor growth in vivo. Overall, our findings reveal major diversity in cancer cell utilization of the cytosolic versus mitochondrial folate cycle across tumors and SLC19A1 expression as a marker for increased reliance on SHMT1.
Subject(s)
Cytosol/metabolism , Folic Acid/metabolism , Glycine Hydroxymethyltransferase/genetics , Mitochondria/metabolism , Neoplasms/metabolism , Reduced Folate Carrier Protein/genetics , Animals , CRISPR-Cas Systems/genetics , Carbon Cycle/genetics , Cell Line , Folic Acid/genetics , Glycine Hydroxymethyltransferase/deficiency , Glycine Hydroxymethyltransferase/metabolism , Humans , Male , Mice , Mice, Inbred NOD , Mice, Knockout , Mice, SCID , Neoplasms/pathology , Reduced Folate Carrier Protein/metabolismABSTRACT
RNA interference (RNAi) applications have evolved from experimental tools to study gene function to the development of a novel class of gene-silencing therapeutics. Despite decades of research, it was not until August 2018 that the US FDA approved the first-ever RNAi drug, marking a new era for RNAi therapeutics. Although there are many limitations associated with the inherent structure of RNA, delivery to target cells and tissues remains the most challenging. RNAs are unable to diffuse across cellular membranes due to their large size and polyanionic backbone and, therefore, require a delivery vector. RNAi molecules can be conjugated to a targeting ligand or packaged into a delivery vehicle. Alnylam has used both strategies in their FDA-approved formulations to achieve efficient delivery to the liver. To harness the full potential of RNAi therapeutics, however, we must be able to target additional cells and tissues. One promising target is the folate receptor α, which is overexpressed in a variety of tumors despite having limited expression and distribution in normal tissues. Folate can be conjugated directly to the RNAi molecule or used to functionalize delivery vehicles. In this review, we compare both delivery strategies and discuss the current state of research in the area of folate-mediated delivery of RNAi molecules.
Subject(s)
Drug Delivery Systems , Folate Receptor 1/genetics , Gene Silencing , RNA, Small Interfering/therapeutic use , Folate Receptor 1/antagonists & inhibitors , Folic Acid/genetics , Folic Acid/metabolism , Genetic Therapy/trends , Humans , Ligands , RNA Interference , RNA, Small Interfering/geneticsABSTRACT
BACKGROUND: The etiology of postpartum psychopathologies are not well understood, but folate metabolism pathways are of potential interest. Demands for folate increase dramatically during pregnancy, low folate level has been associated with psychiatric disorders, and supplementation may improve symptomatology. The MTHFR C677T variant influences folate metabolism and has been implicated in depression during pregnancy. OBJECTIVE: To conduct a prospective longitudinal study to explore the relationship between MTHFR C677T genotype, folate levels, and postpartum psychopathology in at-risk women. HYPOTHESIS: In the first three months postpartum, folate will moderate a relationship between MTHFR genotype and depression, with TT homozygous women having more symptoms than CC homozygous women. METHODS: We recruited 365 pregnant women with a history of mood or psychotic disorder, and at 3 postpartum timepoints, administered the Edinburgh Postnatal Depression Scale (EPDS); Clinician-Administered Rating Scale for Mania (CARS-M) and the Positive and Negative Symptom Scale (PANSS) and drew blood for genotype/folate level analysis. We used robust linear regression to investigate interactions between genotype and folate level on the highest EPDS and CARS-M scores, and logistic regression to explore interactions with PANSS psychosis scores above/below cut-off. RESULTS: There was no significant interaction effect between MTHFR genotype and folate level on highest EPDS (p = 0.36), but there was a significant interaction between genotype, folate level and log(CARS-M) (p = 0.02); post-hoc analyses revealed differences in the effect of folate level between CC/CT, and TT genotypes, with folate level in CC and CT having an inverse relationship with symptoms of mania, while there was no relationship in participants with TT genotype. There was no significant interaction between MTHFR genotype and folate level on the likelihood of meeting positive symptom criteria for psychosis on the PANSS (p = 0.86). DISCUSSION: These data suggest that perhaps there is a relationship between MTHFR C677T, folate level and some symptoms of postpartum psychopathology.
Subject(s)
Depression, Postpartum/genetics , Folic Acid/genetics , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Postpartum Period/genetics , Adult , Alleles , Depression, Postpartum/blood , Depression, Postpartum/pathology , Depression, Postpartum/psychology , Female , Folic Acid/blood , Genetic Predisposition to Disease , Genome-Wide Association Study , Genotype , Humans , Longitudinal Studies , Mania/genetics , Mania/pathology , Mania/psychology , Middle Aged , Postpartum Period/psychology , Pregnancy , Prospective Studies , Psychotic Disorders/genetics , Psychotic Disorders/pathology , Psychotic Disorders/psychology , Risk Factors , Young AdultABSTRACT
Current chemotherapeutic drugs, although effective, lack cell-specific targeting, instigate adverse side effects in healthy tissue, exhibit unfavourable bio-circulation and can generate drug-resistant cancers. The synergistic use of nanotechnology and gene therapy, using nanoparticles (NPs) for therapeutic gene delivery to cancer cells is hereby proposed. This includes the benefit of cell-specific targeting and exploitation of receptors overexpressed in specific cancer types. The aim of this study was to formulate dendrimer-functionalized selenium nanoparticles (PAMAM-SeNPs) containing the targeting moiety, folic acid (FA), for delivery of pCMV-Luc-DNA (pDNA) in vitro. These NPs and their gene-loaded nanocomplexes were physicochemically and morphologically characterized. Nucleic acid-binding, compaction and pDNA protection were assessed, followed by cell-based in vitro cytotoxicity, transgene expression and apoptotic assays. Nanocomplexes possessed favourable sizes (<150 nm) and ζ-potentials (>25 mV), crucial for cellular interaction, and protected the pDNA from degradation in an in vivo simulation. PAMAM-SeNP nanocomplexes exhibited higher cell viability (>85%) compared to selenium-free nanocomplexes (approximately 75%), confirming the important role of selenium in these nanocomplexes. FA-conjugated PAMAM-SeNPs displayed higher overall transgene expression (HeLa cells) compared to their non-targeting counterparts, suggesting enhanced receptor-mediated cellular uptake. Overall, our results bode well for the use of these nano-delivery vehicles in future in vivo studies.
Subject(s)
Dendrimers/chemistry , Gene Transfer Techniques , Metal Nanoparticles/chemistry , Neoplasms/drug therapy , Apoptosis/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , DNA/drug effects , Dendrimers/pharmacology , Folic Acid/chemistry , Folic Acid/genetics , Folic Acid/pharmacology , Folic Acid Antagonists/pharmacology , Humans , Neoplasms/genetics , Neoplasms/pathology , Selenium/chemistry , Selenium/pharmacologyABSTRACT
Folic acid plays an essential role in the central nervous system and cancer. This study aimed to screen genes related to folic acid metabolism. Datasets (GSE80587, GSE65267 and GSE116299) correlated to folic acid were screened in the Gene Expression Omnibus. Weighed gene co-expression network analysis was performed to identify modules associated with sample traits of folic acid and organs (brain, prostate and kidney). Functional enrichment analysis was performed for the eigengenes in modules that were significantly correlated with sample traits. Accordingly, the hub genes and key nodes in the modules were identified using the protein interaction network. A total of 17,252 genes in three datasets were identified. One module, which included 97 genes that were highly correlated with sample traits (including folic acid treatment [cor = -0.57, P = 3e-04] and kidney [cor = -0.68, p = 4e-06]), was screened out. Hub genes, including tetratricopeptide repeat protein 38 (Ttc38) and miR-185, as well as those (including Sema3A, Insl3, Dll1, Msh4 and Snai1) associated with "neuropilin binding", "regulation of reproductive process" and "vitamin D metabolic process", were identified. Genes, including Ttc38, Sema3A, Insl3, Dll1, Msh4 and Snai1, were the novel factors that may be associated with the development of the kidneys and related to folic acid treatment.