title: Response of MiRNA-22-3p and MiRNA-149-5p to Folate Deficiency and the Differential Regulation of MTHFR Expression in Normal and Cancerous Human Hepatocytes.
abstract: OBJECTIVE
  Folic acid (FA) is a core micronutrient involved in DNA synthesis/methylation, and the metabolism of FA is responsible for genomic stability. MicroRNAs may affect gene expression during folate metabolism when cellular homeostasis is changed. This study aimed to reveal the relationship between FA deficiency and the expression of miR-22-p/miR-149-5p and the targeted regulation of miR-22-3p/miR-149-5p on the key folate metabolic gene Methylenetetrahydrofolate reductase (MTHFR).
  
  
  METHODS
  Normal (HL-7702 cells) and cancerous (QGY-7703 cells) human hepatocytes were intervened in modified RPMI 1640 with FA deficiency for 21 days. The interaction between MTHFR and the tested miRNAs was verified by Dual-Luciferase Reporter Assays. The changes in the expression of miR-22-3p/miR-149-5p in response to FA deficiency were detected by Poly (A) Tailing RT-qPCR, and the expression of MTHFR at both the transcriptional and translational levels was determined by RT-qPCR and Western blotting, respectively.
  
  
  RESULTS
  MiR-22-3p/miR-149-5p directly targeted the 3'UTR sequence of the MTHFR gene. FA deficiency led to an upregulation of miR-22-3p/miR-149-5p expression in QGY-7703/HL-7702 cells, while the transcription of MTHFR was decreased in QGY-7703 cells but elevated in HL-7702 cells. Western blotting showed that FA deficiency resulted in a decline of the MTHFR protein in QGY-7703 cells, whereas in HL-7702 cells, the MTHFR protein level remained constant.
  
  
  CONCLUSIONS
  The results suggested that miR-22-3p/miR-149-5p exert different post-transcriptional effects on MTHFR under conditions of FA deficiency in normal and cancerous human hepatocytes. The results also implied that miR-22-3p/miR-149-5p might exert anticancer effects in cases of long-term FA deficiency.
authors.affiliation: School of Life Science, Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, Yunnan, People's Republic of China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.affiliation: School of Life Science, Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, Yunnan, People's Republic of China.
authors.forename: Juan
authors.initials: J
authors.lastname: Ni
authors.affiliation: School of Life Science, Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, Yunnan, People's Republic of China.
authors.forename: Yao-Xian
authors.initials: YX
authors.lastname: Liu
authors.affiliation: School of Life Science, Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, Yunnan, People's Republic of China.
authors.forename: Han
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Life Science, Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, Yunnan, People's Republic of China.
authors.forename: Zi-Qing
authors.initials: ZQ
authors.lastname: Liang
authors.affiliation: School of Life Science, Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, Yunnan, People's Republic of China.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D045744:Cell Line, Tumor; D019175:DNA Methylation; D018450:Disease Progression; D005492:Folic Acid / Q000378:metabolism; D005494:Folic Acid Deficiency / Q000378:metabolism*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D022781:Hepatocytes / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism*; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs / Q000378:metabolism*; D011061:Poly A / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: C551557:MIRN149 microRNA, human; C548375:MIRN22 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger; D011061:Poly A; D005492:Folic Acid; C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2)