Forced expression of miR-143 and -145 in cardiomyocytes induces cardiomyopathy with a reductive redox shift
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(2020) 25:40
Cellular & Molecular Biology Letters
RESEARCH
Open Access
Forced expression of miR-143 and -145 in cardiomyocytes induces cardiomyopathy with a reductive redox shift Kota Ogawa1, Akiko Noda1, Jun Ueda2,3†, Takehiro Ogata4†, Rumiko Matsuyama1, Yuji Nishizawa1, Shanlou Qiao1, Satoru Iwata1,2,5, Morihiro Ito1, Yoshitaka Fujihara6,7, Masatoshi Ichihara1, Koichi Adachi8, Yuji Takaoka1 and Takashi Iwamoto1,2* * Correspondence: iwamoto@isc. chubu.ac.jp † Jun Ueda and Takehiro Ogata contributed equally to this work. 1 Department of Biomedical Sciences, Chubu University Graduate School of Life and Health Sciences, Kasugai, Aichi, Japan 2 Center for Education in Laboratory Animal Research, Chubu University, Kasugai, Aichi, Japan Full list of author information is available at the end of the article
Abstract Background: Animal model studies show that reductive stress is involved in cardiomyopathy and myopathy, but the exact physiological relevance remains unknown. In addition, the microRNAs miR-143 and miR-145 have been shown to be upregulated in cardiac diseases, but the underlying mechanisms associated with these regulators have yet to be explored. Methods: We developed transgenic mouse lines expressing exogenous miR-143 and miR-145 under the control of the alpha-myosin heavy chain (αMHC) promoter/ enhancer. Results: The two transgenic lines showed dilated cardiomyopathy-like characteristics and early lethality with markedly increased expression of miR-143. The expression of hexokinase 2 (HK2), a cardioprotective gene that is a target of miR-143, was strongly suppressed in the transgenic hearts, but the in vitro HK activity and adenosine triphosphate (ATP) content were comparable to those observed in wild-type mice. In addition, transgenic complementation of HK2 expression did not reduce mortality rates. Although HK2 is crucial for the pentose phosphate pathway (PPP) and glycolysis, the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) was unexpectedly higher in the hearts of transgenic mice. The expression of gammaglutamylcysteine synthetase heavy subunit (γ-GCSc) and the in vitro activity of glutathione reductase (GR) were also higher, suggesting that the recycling of GSH and its de novo biosynthesis were augmented in transgenic hearts. Furthermore, the expression levels of glucose-6-phosphate dehydrogenase (G6PD, a rate-limiting enzyme for the PPP) and p62/SQSTM1 (a potent inducer of glycolysis and glutathione production) were elevated, while p62/SQSTM1 was upregulated at the mRNA level rather than as a result of autophagy inhibition. Consistent with this observation, nuclear factor erythroid-2 related factor 2 (Nrf2), Jun N-terminal kinase (JNK) and inositol-requiring enzyme 1 alpha (IRE1α) were activated, all of which are known to induce p62/SQSTM1 expression. (Continued on next page)
© The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any med
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