Dicer1 mediated miRNA processing shapes the mRNA profile and function of murine platelets

Rowley, JW; Chappaz, S; Corduan, A; Chong, MM; Campbell, R; Khoury, A; Manne, BK; Wurtzel, JG; Michael, JV; Goldfinger, LE; Mumaw, MM; Nieman, MT; Kile, BT; Provost, P; Weyrich, AS

Author(s): Rowley, JW; Chappaz, S; Corduan, A; Chong, MM; Campbell, R; Khoury, A; Manne, BK; Wurtzel, JG; Michael, JV; Goldfinger, LE; Mumaw, MM; Nieman, MT; Kile, BT; Provost, P; Weyrich, AS;
Details: Publication Year 2016-04-07,Volume 127,Issue #14,Page 1743-51
Journal Title: Blood
Publication Type: Journal Article
Abstract: Human platelets contain microRNAs (miRNAs) and miRNA processing machinery, but their contribution to platelet function remains incompletely understood. Here, we show that murine megakaryocyte-specific knockdown of Dicer1, the ribonuclease that cleaves miRNA precursors (pre-miRNAs) into mature miRNAs, reduces the level of the majority of miRNAs in platelets. This leads to altered platelet mRNA expression profiles and mild thrombocytopenia. Fibrinogen receptor subunits Itga2b (alphaIIb) and Itgb3 (beta3) mRNAs were among the differentially expressed transcripts that are increased in platelets lacking Dicer1. Argonaute 2 (Ago2), a member of the miRNA silencing complex, co-immunoprecipitated with alphaIIb and beta3 mRNAs in wild-type platelets. Furthermore, co-immunoprecipitation experiments suggested reduced alphaIIb/beta3/Ago2 complexes in miRNA deficient platelets. These results suggested that miRNAs regulate both integrin subunits. Subsequent 3' untranslated region (UTR) luciferase reporter assays confirmed that the translation of both alphaIIb and beta3 mRNAs can be regulated by miRNAs miR-326, miR-128, miR-331 and miR-500. Consistent with these molecular changes, deletion of Dicer1 resulted in increased surface expression of integrins alphaIIb and beta3, and enhanced platelet binding to fibrinogen in vivo and in vitro. Heightened platelet reactivity, shortened tail bleeding time, and reduced survival following collagen/epinephrine induced pulmonary embolism were also observed in Dicer1 deficient animals. Combined Pf4-cre mediated deletion of Drosha and Dicer1 did not significantly exacerbate phenotypes observed in single Dicer1 knockout mice. In summary, these findings indicate that Dicer1-dependent generation of mature miRNAs in late-stage megakaryocytes and platelets modulates the expression of target mRNAs important for the hemostatic and thrombotic function of platelets.
Publisher: ASH
Research Division(s): Chemical Biology
PubMed ID: 26773046
Publisher's Version: https://doi.org/10.1182/blood-2015-07-661371
NHMRC Grants: NHMRC/461219, NHMRC/1016647,
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2016-01-29 11:46:09

Last Modified: 2016-05-09 12:30:44