MicroRNA 648 Targets ET-1 mRNA and is cotranscriptionally regulated with MICAL3 by PAX5.
Pulmonary hypertension (PHT) is associated with high mortality in sickle cell anemia (SCA). Previously, we showed that elevated levels of placenta growth factor (PlGF) in SCA patients correlate with increased levels of the potent vasoconstrictor endothelin-1 (ET-1) and PHT. Moreover, PlGF induced the expression of ET-1 via hypoxia-inducible factor 1α. Here, we show a novel example of ET-1 posttranscriptional regulation by PlGF via action of microRNA 648 (miR-648), which is subject to transcriptional coregulation with its host gene, MICAL3 (microtubule-associated monooxygenase, calponin, and LIM domain containing 3gene). PlGF repressed expression of miR-648 in endothelial cells. Luciferase reporter assays using wild-type and mutant ET-1 3' untranslated region (UTR) constructs, and transfection of miR-648 mimics showed that miR-648 targets the 3' UTR of ET-1 mRNA. Since miR-648 is located in a 5'-proximal intron of MICAL3, we examined which of three potential promoters was responsible for its expression. The MICAL3 distal promoter (P1) was the predominant promoter used for transcription of pre-miR-648, and it was under positive control by PAX5 (paired box protein 5) transcription factor, as demonstrated by the loss and gain of function of PAX5 activity, and chromatin immunoprecipitation analysis. These studies provide a novel link wherein PlGF-mediated downregulation of PAX5 attenuates miR-648 expression leading to increased ET-1 levels that are known to induce PHT in SCA.
Department of Biochemistry and Molecular Biology, Keck School of Medicine of University of Southern California, Los Angeles, California, USA.
Chen
C
Li
Department of Biochemistry and Molecular Biology, Keck School of Medicine of University of Southern California, Los Angeles, California, USA.
Caryn S
CS
Gonsalves
Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Marthe-Sandrine
MS
Eiymo Mwa Mpollo
Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Punam
P
Malik
Department of Molecular Microbiology and Immunology, Keck School of Medicine of University of Southern California, Los Angeles, California, USA.
Stanley M
SM
Tahara
Department of Biochemistry and Molecular Biology, Keck School of Medicine of University of Southern California, Los Angeles, California, USA vkalra@usc.edu.
Vijay K
VK
Kalra
D000755:Anemia, Sickle Cell / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D051757:PAX5 Transcription Factor / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D019332:Endothelin-1; C000597135:MIRN-648 microRNA, human; D035683:MicroRNAs; D051757:PAX5 Transcription Factor; C497281:PAX5 protein, human; D012333:RNA, Messenger; D014157:Transcription Factors; C561623:MICAL3 protein, human; D006899:Mixed Function Oxygenases