Objective Circular RNAs(circRNAs)participate in several important pathological processes and have been used in the diagnosis and treatment of various diseases.This study aimed to investigate the role of circRNAs in ne...Objective Circular RNAs(circRNAs)participate in several important pathological processes and have been used in the diagnosis and treatment of various diseases.This study aimed to investigate the role of circRNAs in neural tube defects(NTDs).Method We characterized circRNA-associated competitive endogenous RNA(ceRNA)networks in brain tissue of low folate-induced NTDs mouse at embryonic day 13.5 by high-throughput sequencing.The expression levels of Circzfp644,miR-20-5p and Gas7 were detected by RT-PCR.Gas7 and Circzfp644functions were determined by miRNA-mimics and inhibitors in mouse teratocarcinoma cells(F9 cells),and luciferase gene reporter assay was assessed in the F9 cells.In addition,the expression levels of Circzfp644,miR-20-5p and Gas7 were determined by Nanostring in human NTDs tissues.Results We detected 57 circRNA transcripts,16 miRNAs,and 148 mRNAs that were significantly dysregulated in NTDs brain tissues compared with their expression levels in control(normal)tissues.Circzfp644 shared miRNA response elements with the growth arrest specific 7(Gas7)gene and competitively bound with miR-20-5p to increase the expression of Gas7.Downregulation of Circzfp644and Gas7 and upregulation of miR-20-5p were found in human NTD tissue.Conclusion This study provides new perspectives on the role of circRNAs in nervous system development and the pathogenesis of NTDs.展开更多
Objective:The purpose of this study was to examine the role of rare variants in the one-carbon metabolic pathway in the etiology of the cerebral folate deficiency(CFD)syndrome.The CFD syndrome is a neurometabolic synd...Objective:The purpose of this study was to examine the role of rare variants in the one-carbon metabolic pathway in the etiology of the cerebral folate deficiency(CFD)syndrome.The CFD syndrome is a neurometabolic syndrome identified by low concentrations of 5-methyltetrahydrofolate(5-MTHF)in the cerebrospinal fluid(CSF)in spite of near-normal peripheral folate levels resulting in neurodevelopmental disorders.Methods:The localized folate metabolism impairments in CFD are thought to be either the result of mutations in genes responsible for folate transport or folate turnover through degradation.Genes that have been previously implicated in the etiology of CFD include folate receptor alpha-1(FOLR1),dihydrofolate reductase,proton-coupled folate transporter,and capicua.We performed whole-exome sequencing(WES)analysis of a CFD patient that revealed 99 novel missense mutations,of which 21 were classified as damaging mutations through the Poly-Phen2 prediction algorithm.In vitro functional studies were conducted by transient transfection of wild-type and mutant MTHFS into HEK293T cells to determine the impact of the variants on enzyme activity.Results:Of the damaging variants identified in the WES studies,we focused on the gene coding for the enzyme 5,10-methenyl-tetrahydrofolate synthetase(MTHFS).This enzyme catalyzes the production of methenyl THF which is subsequently converted to 5-MTHF.The CFD patient described within was found to carry a homozygous mutation,c.101G>T(p.R34L,rs200058464)in MTHFS,while the parents of the proband are heterozygotes for the MTHFS gene,and the healthy sibling is not a carrier.Conclusion:The mutant allele displayed a 50%reduction in luciferase activity(P<0.05),suggesting that homozygous loss of the MTHFS gene may play a significant role in the development of CFD.展开更多
Folate deficiency and its association with cancer have been studied in the literature, but its clinical impact is still unknown. Folate deficiency and its result on gastric cancer is a mysterious part of oncology, wit...Folate deficiency and its association with cancer have been studied in the literature, but its clinical impact is still unknown. Folate deficiency and its result on gastric cancer is a mysterious part of oncology, with ongoing studies hopefully clarifying its impact on gastric cancer management. Lee et al studied folate deficiency and its impact on staging and clinical results. Here we try to contribute to the field by expressing our own thoughts about the paper.展开更多
Objective This study aimed to investigate the effects of N,N-dimethylglycine(DMG) on the concentration and metabolism of plasma homocysteine(pHcy) in folate-sufficient and folate-deficient rats.Methods In this study, ...Objective This study aimed to investigate the effects of N,N-dimethylglycine(DMG) on the concentration and metabolism of plasma homocysteine(pHcy) in folate-sufficient and folate-deficient rats.Methods In this study, 0.1% DMG was supplemented in 20% casein diets that were either folatesufficient(20 C) or folate-deficient(20 CFD). Blood and liver of rats were subjected to assays of Hcy and its metabolites. Hcy and its related metabolite concentrations were determined using a liquid chromatographic system.Results Folate deprivation significantly increased pHcy concentration in rats fed 20 C diet(from 14.19 ±0.39 μmol/L to 28.49 ± 0.50 μmol/L;P < 0.05). When supplemented with DMG, pHcy concentration was significantly decreased(12.23 ± 0.18 μmol/L) in rats fed 20 C diet but significantly increased(31.56 ±0.59 μmol/L) in rats fed 20 CFD. The hepatic methionine synthase activity in the 20 CFD group was significantly lower than that in the 20 C group;enzyme activity was unaffected by DMG supplementation regardless of folate sufficiency. The activity of hepatic cystathionine β-synthase(CBS) in the 20 CFD group was decreased but not in the 20 C group;DMG supplementation enhanced hepatic CBS activity in both groups, in which the effect was significant in the 20 C group but not in the other group.Conclusion DMG supplementation exhibited hypohomocysteinemic effects under folate-sufficient conditions. By contrast, the combination of folate deficiency and DMG supplementation has deleterious effect on pHcy concentration.展开更多
基金supported by the National Natural Sciences [82071690,81971390]Research Foundation of Capital Institute of Pediatrics [FX-2020-05,CXYJ-2-21-09]+1 种基金Public service development and reform pilot project of Beijing Medical Research Institute [BMR2021-1]Beijing Hospitals Authority Clinical technology innovation program [XLMX 202110]。
文摘Objective Circular RNAs(circRNAs)participate in several important pathological processes and have been used in the diagnosis and treatment of various diseases.This study aimed to investigate the role of circRNAs in neural tube defects(NTDs).Method We characterized circRNA-associated competitive endogenous RNA(ceRNA)networks in brain tissue of low folate-induced NTDs mouse at embryonic day 13.5 by high-throughput sequencing.The expression levels of Circzfp644,miR-20-5p and Gas7 were detected by RT-PCR.Gas7 and Circzfp644functions were determined by miRNA-mimics and inhibitors in mouse teratocarcinoma cells(F9 cells),and luciferase gene reporter assay was assessed in the F9 cells.In addition,the expression levels of Circzfp644,miR-20-5p and Gas7 were determined by Nanostring in human NTDs tissues.Results We detected 57 circRNA transcripts,16 miRNAs,and 148 mRNAs that were significantly dysregulated in NTDs brain tissues compared with their expression levels in control(normal)tissues.Circzfp644 shared miRNA response elements with the growth arrest specific 7(Gas7)gene and competitively bound with miR-20-5p to increase the expression of Gas7.Downregulation of Circzfp644and Gas7 and upregulation of miR-20-5p were found in human NTD tissue.Conclusion This study provides new perspectives on the role of circRNAs in nervous system development and the pathogenesis of NTDs.
文摘Objective:The purpose of this study was to examine the role of rare variants in the one-carbon metabolic pathway in the etiology of the cerebral folate deficiency(CFD)syndrome.The CFD syndrome is a neurometabolic syndrome identified by low concentrations of 5-methyltetrahydrofolate(5-MTHF)in the cerebrospinal fluid(CSF)in spite of near-normal peripheral folate levels resulting in neurodevelopmental disorders.Methods:The localized folate metabolism impairments in CFD are thought to be either the result of mutations in genes responsible for folate transport or folate turnover through degradation.Genes that have been previously implicated in the etiology of CFD include folate receptor alpha-1(FOLR1),dihydrofolate reductase,proton-coupled folate transporter,and capicua.We performed whole-exome sequencing(WES)analysis of a CFD patient that revealed 99 novel missense mutations,of which 21 were classified as damaging mutations through the Poly-Phen2 prediction algorithm.In vitro functional studies were conducted by transient transfection of wild-type and mutant MTHFS into HEK293T cells to determine the impact of the variants on enzyme activity.Results:Of the damaging variants identified in the WES studies,we focused on the gene coding for the enzyme 5,10-methenyl-tetrahydrofolate synthetase(MTHFS).This enzyme catalyzes the production of methenyl THF which is subsequently converted to 5-MTHF.The CFD patient described within was found to carry a homozygous mutation,c.101G>T(p.R34L,rs200058464)in MTHFS,while the parents of the proband are heterozygotes for the MTHFS gene,and the healthy sibling is not a carrier.Conclusion:The mutant allele displayed a 50%reduction in luciferase activity(P<0.05),suggesting that homozygous loss of the MTHFS gene may play a significant role in the development of CFD.
文摘Folate deficiency and its association with cancer have been studied in the literature, but its clinical impact is still unknown. Folate deficiency and its result on gastric cancer is a mysterious part of oncology, with ongoing studies hopefully clarifying its impact on gastric cancer management. Lee et al studied folate deficiency and its impact on staging and clinical results. Here we try to contribute to the field by expressing our own thoughts about the paper.
基金supported by the National Natural Science Foundation of China under the Grant No. 81973048a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, Culture, Sports and Technology of Japan [JSPS-C-21580137]。
文摘Objective This study aimed to investigate the effects of N,N-dimethylglycine(DMG) on the concentration and metabolism of plasma homocysteine(pHcy) in folate-sufficient and folate-deficient rats.Methods In this study, 0.1% DMG was supplemented in 20% casein diets that were either folatesufficient(20 C) or folate-deficient(20 CFD). Blood and liver of rats were subjected to assays of Hcy and its metabolites. Hcy and its related metabolite concentrations were determined using a liquid chromatographic system.Results Folate deprivation significantly increased pHcy concentration in rats fed 20 C diet(from 14.19 ±0.39 μmol/L to 28.49 ± 0.50 μmol/L;P < 0.05). When supplemented with DMG, pHcy concentration was significantly decreased(12.23 ± 0.18 μmol/L) in rats fed 20 C diet but significantly increased(31.56 ±0.59 μmol/L) in rats fed 20 CFD. The hepatic methionine synthase activity in the 20 CFD group was significantly lower than that in the 20 C group;enzyme activity was unaffected by DMG supplementation regardless of folate sufficiency. The activity of hepatic cystathionine β-synthase(CBS) in the 20 CFD group was decreased but not in the 20 C group;DMG supplementation enhanced hepatic CBS activity in both groups, in which the effect was significant in the 20 C group but not in the other group.Conclusion DMG supplementation exhibited hypohomocysteinemic effects under folate-sufficient conditions. By contrast, the combination of folate deficiency and DMG supplementation has deleterious effect on pHcy concentration.
