Enhanced Expression of miR-199b-5p Promotes Proliferation of Pancreatic β-Cells by Down-Regulation of MLK3.
The initiation of β-cell proliferation to recover reduced β-cell mass is considered as one of the attractive therapeutic approaches for type 1 and 2 diabetes. In this study, we investigated the involvement of miRNAs in β-cell proliferation.



Global miRNA array analysis of pancreas tissue was carried out using a 60% partial pancreatectomy (PPx) rodent model, which is a well-characterized model for pancreatic regeneration with accelerated proliferation of β-cells. To explore miRNAs with mitogenic activity on β-cells, precursors and antisense oligonucleotides (ASOs) for miRNAs were transfected into a primary islet monolayer cell cultures isolated from adult rats in order to modify their expression and proliferation of β-cells.



We found that miR-199b-5p, which was up-regulated 2.6 times in the pancreas of the PPx treated group, significantly enhanced the proliferation of β-cells when its precursor was over-expressed. Target genes of miR-199b-5p were investigated and Mixed lineage kinase-3 (MLK3) was identified as one of the candidates since its expression was down-regulated through an interaction with miR-199b-5p and siRNA treatment for MLK3 enhanced the proliferation of β-cells.



Our data suggest that the up-regulation of miR-199b-5p enhances proliferation of β-cells at least in part through down-regulation of MLK3.
Integrated Technology Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Ltd., 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan.
Rie
R
Sato-Kunisada
Nobuyo
N
Yoshida
Shingo
S
Nakamura
Hidefumi
H
Uchiyama
Hirokazu
H
Matsumoto
D000818:Animals; D049109:Cell Proliferation / Q000235:genetics*; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism; D003920:Diabetes Mellitus / Q000235:genetics / Q000628:therapy; D015536:Down-Regulation / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D050417:Insulin-Secreting Cells / Q000166:cytology*; D020930:MAP Kinase Kinase Kinases / Q000096:biosynthesis / Q000235:genetics*; D008297:Male; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D016376:Oligonucleotides, Antisense / Q000235:genetics; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11
D019938:Cyclin D1; D019927:Cyclin E; D020930:MAP Kinase Kinase Kinases; D035683:MicroRNAs; D016376:Oligonucleotides, Antisense; D034741:RNA, Small Interfering; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11; C530106:Ccnd1 protein, rat; C552425:MIRN199 microRNA, rat; C574979:MIRN375 microRNA, rat