AIMS: Our aim was to identify new microRNAs (miRNAs) implicated in pathological vascular smooth muscle cells (VSMCs) proliferation and characterize their mechanism of action. METHODS AND RESULTS: MicroRNAs microarray and qRT-PCR results lead us to focus on miR-424 or its rat ortholog miR-322 (miR-424/322). In vitro mir-424/322 level was decreased shortly after the induction of proliferation and increased in a time-dependent manner later on. In vivo its expression increased in the rat carotid artery from Day 4 up to Day 30 after injury. miR-424/322 overexpression in vitro inhibited proliferation and migration without affecting apoptosis and prevented VSMC dedifferentiation. Furthermore, miR-424/322 overexpression resulted in decreased expression of its predicted targets: cyclin D1 and Ca(2+)-regulating proteins calumenin and stromal-interacting molecule 1 (STIM1). Using reporter luciferase assays, we confirmed that cyclin D1 and calumenin mRNAs were direct targets of miR-322, whereas miR-322 effect on STIM1 was indirect. Nevertheless, consistent with the decreased STIM1 level, the store-operated Ca(2+) entry was reduced. We hypothesized that miR-424/322 could be a negative regulator of proliferation overridden in pathological situations. Thus, we overexpressed miR-424/322 in injured rat carotid arteries using an adenovirus, and demonstrated a protective effect against restenosis. CONCLUSION: Our results demonstrate that miR-424/322 is up-regulated after vascular injury. This is likely an adaptive response to counteract proliferation, although this mechanism is overwhelmed in pathological situations such as injury-induced restenosis.
AIMS: Our aim was to identify new microRNAs (miRNAs) implicated in pathological vascular smooth muscle cells (VSMCs) proliferation and characterize their mechanism of action. METHODS AND RESULTS: MicroRNAs microarray and qRT-PCR results lead us to focus on miR-424 or its rat ortholog miR-322 (miR-424/322). In vitro mir-424/322 level was decreased shortly after the induction of proliferation and increased in a time-dependent manner later on. In vivo its expression increased in the rat carotid artery from Day 4 up to Day 30 after injury. miR-424/322 overexpression in vitro inhibited proliferation and migration without affecting apoptosis and prevented VSMC dedifferentiation. Furthermore, miR-424/322 overexpression resulted in decreased expression of its predicted targets: cyclin D1 and Ca(2+)-regulating proteins calumenin and stromal-interacting molecule 1 (STIM1). Using reporter luciferase assays, we confirmed that cyclin D1 and calumenin mRNAs were direct targets of miR-322, whereas miR-322 effect on STIM1 was indirect. Nevertheless, consistent with the decreased STIM1 level, the store-operated Ca(2+) entry was reduced. We hypothesized that miR-424/322 could be a negative regulator of proliferation overridden in pathological situations. Thus, we overexpressed miR-424/322 in injured rat carotid arteries using an adenovirus, and demonstrated a protective effect against restenosis. CONCLUSION: Our results demonstrate that miR-424/322 is up-regulated after vascular injury. This is likely an adaptive response to counteract proliferation, although this mechanism is overwhelmed in pathological situations such as injury-induced restenosis.
Authors: John R Finnerty; Wang-Xia Wang; Sébastien S Hébert; Bernard R Wilfred; Guogen Mao; Peter T Nelson Journal: J Mol Biol Date: 2010-08-01 Impact factor: 5.469
Authors: Goutam Ghosh; Indira V Subramanian; Neeta Adhikari; Xiaoxiao Zhang; Hemant P Joshi; David Basi; Y S Chandrashekhar; Jennifer L Hall; Sabita Roy; Yan Zeng; Sundaram Ramakrishnan Journal: J Clin Invest Date: 2010-10-25 Impact factor: 14.808
Authors: A R R Forrest; M Kanamori-Katayama; Y Tomaru; T Lassmann; N Ninomiya; Y Takahashi; M J L de Hoon; A Kubosaki; A Kaiho; M Suzuki; J Yasuda; J Kawai; Y Hayashizaki; D A Hume; H Suzuki Journal: Leukemia Date: 2009-12-03 Impact factor: 11.528