miR-486 is modulated by stretch and increases ventricular growth
Stephan Lange, … , Juan C. del Álamo, Vishal Nigam
Stephan Lange, … , Juan C. del Álamo, Vishal Nigam
Published October 3, 2019; First published September 12, 2019
Citation Information: JCI Insight. 2019;4(19):e125507. https://doi.org/10.1172/jci.insight.125507.
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Research Article Cardiology Cell biology

miR-486 is modulated by stretch and increases ventricular growth

Abstract

Perturbations in biomechanical stimuli during cardiac development contribute to congenital cardiac defects such as hypoplastic left heart syndrome (HLHS). This study sought to identify stretch-responsive pathways involved in cardiac development. miRNA-Seq identified miR-486 as being increased in cardiomyocytes exposed to cyclic stretch in vitro. The right ventricles (RVs) of patients with HLHS experienced increased stretch and had a trend toward higher miR-486 levels. Sheep RVs dilated from excessive pulmonary blood flow had 60% more miR-486 compared with control RVs. The left ventricles of newborn mice treated with miR-486 mimic were 16.9%–24.6% larger and displayed a 2.48-fold increase in cardiomyocyte proliferation. miR-486 treatment decreased FoxO1 and Smad signaling while increasing the protein levels of Stat1. Stat1 associated with Gata-4 and serum response factor (Srf), 2 key cardiac transcription factors with protein levels that increase in response to miR-486. This is the first report to our knowledge of a stretch-responsive miRNA that increases the growth of the ventricle in vivo.

Authors

Stephan Lange, Indroneal Banerjee, Katrina Carrion, Ricardo Serrano, Louisa Habich, Rebecca Kameny, Luisa Lengenfelder, Nancy Dalton, Rudolph Meili, Emma Börgeson, Kirk Peterson, Marco Ricci, Joy Lincoln, Majid Ghassemian, Jeffery Fineman, Juan C. del Álamo, Vishal Nigam

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Figure 5

miR-486 is sufficient to increase Stat1 levels in vivo and in vitro.

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miR-486 is sufficient to increase Stat1 levels in vivo and in vitro. (A)...
(A) Volcano plot showing the results of a mass spectrometry proteome comparison of proteins from miR-486 mimic–treated hearts as compared with scrambled BlockIT controls. Stat1 was one of the most upregulated proteins. Sarcomeric proteins highlighted by asterisks were found dysregulated only in iTRAQ analysis but not in immunoblots (Supplemental Figure 1, C and D) (B) Pathway enrichment analysis of significantly changed proteins. (C) Immunoblot analysis of heart lysates from miR-486– or BlockIT-treated (CTL) neonatal mice demonstrates that total Stat1 levels are increased in miR-486-treated mice. Of note, miR-486 hearts did not demonstrate alterations in total Jak1 or Stat3 levels. (D and E) Isolated cardiomyocytes transfected with miR-486 mimic have significantly higher total normalized Stat1 (1.74 ± 0.1249, n = 3, P = 0.006, as determined by t test [*P < 0.05, **P < 0.01 vs. control]) and p-Stat1 Ser727 levels (2.425 ± 0.3063, n = 3, P = 0.035, as determined by t test) as compared with scramble control–treated (BlockIT) cells. Protein levels were normalized to GAPDH. (F) Pie chart showing that 37.6% of genes upregulated in cardiomyocytes exposed to cyclic stretch in vitro are predicted have Stat1-binding sites (left), and pie chart showing that 36.1% of genes upregulated in the RVs of HLHS patients as compared with control RVs are predicted to have Stat1-binding sites (right).