Forced expression of miR-143 and -145 in cardiomyocytes induces cardiomyopathy with a reductive redox shift

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 gamma-glutamylcysteine 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. Conclusions Overexpression of miR-143 and miR-145 leads to a unique dilated cardiomyopathy phenotype with a reductive redox shift despite marked downregulation of HK2 expression. Reductive stress may be involved in a wider range of cardiomyopathies than previously thought.

Bioactivity and miRNome Profiling of Native Extracellular Vesicles in Human Induced Pluripotent Stem Cell‐Cardiomyocyte Differentiation

“…K‐means clustering revealed distinguishable miRNA expression patterns among the samples, with three main miRNA subsets emerging (Figure 6B ). miRNA from the first cluster (miR‐378a, miR‐143, miR 125a), strongly expressed in the mammalian heart, and largely involved in muscle development and hypertrophy, [ 52 , 53 , 54 , 55 , 56 ] were downregulated in hiPSC‐EV and gradually upregulated along cardiomyocyte differentiation (with exception of miR‐378a, which is also expressed in hiPSC‐EV). The second miRNA cluster (miR‐200b/c, miR‐335, miR‐302b/c, miR‐363, miR‐183, miR‐182), contained pluripotency‐associated miRNAs, [ 31 , 32 , 33 , 57 ] which were progressively downregulated in EV secreted from committed and mature cells.…”

miR‐145transgenic mice develop cardiopulmonary complications leading to postnatal death

“…Detailed examination of the hearts of the transgenic pups show significant right‐sided hypertrophy, however, the heart valves and cardiomyocytes in both ventricles appeared structurally normal. A recent report of transgenic miR ‐ 143 / 145 expression in hearts utilizing αMHC ‐ Cre showed left ventricular hypertrophy leading to death beginning at 8 weeks of age (Ogawa et al, 2020 ). Thus, the most likely cause of death of our miR145Tg ; MCC pups is in response to pulmonary distress caused by pathological pulmonary remodeling.…”

LncRNA FLVCR1-AS1 mediates miR-23a-5p/SLC7A11 axis to promote malignant behavior of cervical cancer cells

“…Carrying out of all operations was in the light of the manufacturer’s instructions. Design and performance of all experiments were three times [ 19 ].…”