miR-21-5p regulates mitochondrial respiration and lipid content in H9C2 cells

Abstract

Cardiovascular-related pathologies are the single leading cause of death in patients with chronic kidney disease (CKD). Previously, we found that a 5/6th nephrectomy model of CKD leads to an upregulation of miR-21-5p in the left ventricle, targeting peroxisome proliferator-activated receptor-α and altering the expression of numerous transcripts involved with fatty acid oxidation and glycolysis. In the present study, we evaluated the potential for knockdown or overexpression of miR-21-5p to regulate lipid content, lipid peroxidation, and mitochondrial respiration in H9C2 cells. Cells were transfected with anti-miR-21-5p (40 nM), pre-miR-21-5p (20 nM), or the appropriate scrambled oligonucleotide controls before lipid treatment in culture or as part of the Agilent Seahorse XF fatty acid oxidation assay. Overexpression of miR-21-5p attenuated the lipid-induced increase in cellular lipid content, whereas suppression of miR-21-5p augmented it. The abundance of malondialdehyde, a product of lipid peroxidation, was significantly increased with lipid treatment in control cells but attenuated in pre-miR-21-5p-transfected cells. This suggests that miR-21-5p reduces oxidative stress. The cellular oxygen consumption rate (OCR) was increased in both pre-miR-21-5p- and anti-miR-21-5p-transfected cells. Levels of intracellular ATP were significantly higher in anti-mR-21-5p-transfected cells. Pre-miR-21-5p blocked additional increases in OCR in response to etomoxir and palmitic acid. Conversely, anti-miR-21-5p-transfected cells exhibited reduced OCR with both etomoxir and palmitic acid, and the glycolytic capacity was concomitantly reduced. Together, these results indicate that overexpression of miR-21-5p attenuates both lipid content and lipid peroxidation in H9C2 cells. This likely occurs by reducing cellular lipid uptake and utilization, shifting cellular metabolism toward reliance on the glycolytic pathway. NEW & NOTEWORTHY Both overexpression and suppression of miR-21-5p augment basal and maximal mitochondrial respiration. Our data suggest that reliance on glycolytic and fatty acid oxidation pathways can be modulated by the abundance of miR-21-5p within the cell. miR-21-5p regulation of mitochondrial respiration can be modulated by extracellular lipids.

Exosome-Mediated miR-21 Was Involved in the Promotion of Structural and Functional Recovery Effect Produced by Electroacupuncture in Sciatic Nerve Injury

“…As an extensively studied miRNA, miR-21 can mediate inflammation [ 70 ], oxidative stress [ 71 ], cell apoptosis [ 72 ], proliferation [ 73 ], and regulate multiple signal pathways, including the protein kinase B (AKT) signaling pathway [ 74 , 75 ], extracellular regulated protein kinases (ERK) signaling pathway [ 76 , 77 ], and nuclear factor kappa-B (NF- κ B) [ 78 ]. Plenty of studies have proven that miR-21 participates in the occurrence and development of tumors [ 79 , 80 ], cardiovascular [ 81 ] and lung diseases [ 82 , 83 ], glaucoma intraocular pressure [ 84 ], age-related skin wound healing [ 85 ], sepsis, and acute kidney injury [ 86 ].…”

Redox signaling in aging kidney and opportunity for therapeutic intervention through natural products

“…Moreover, fibrosis-associated microRNA-21 was the most upregulated microRNAs in animal models of allogenic kidney transplantation, the antagonism of which had beneficial effects on chronic renal allograft dysregulation, highlighting microRNA silencing might be a promising therapeutic option in patients following kidney transplantation via halting the progression of chronic renal allograft dysfunction [102]. Nonetheless, the emerging consensus that both overexpression and suppression of microRNA-21 could accelerate basal as well as maximal mitochondrial respiration is increasingly recognized [103], which is quite distinct from that of previous investigations. Collectively, thus far, there is a paucity of relevant studies about the optimal level of microRNA-21 in clinical use, and the therapeutic efficacy of microRNA-21 silencing in human beings remains a tremendous challenge due to the severely limited investigations.…”

The Pivotal Role of miRNA-21 in Myocardial Metabolic Flexibility in Response to Short- and Long-term High Glucose Treatment: Evidence in Human Cardiomyocyte Cell Line

“…In agreement, a recent study provides direct evidence that modulation of miR-21 levels can impact substrate utilization and mitochondrial respiration in H9C2 cells. The different substrate availability can further modulate this effect (29). Furthermore, in our study, miRNA-21 inhibition activated in ammation and apoptosis pathways, compromised mitochondrial function (as demonstrated by the reduction in O 2 consumption and ATP production), thus inducing a functional failure with the inability to meet energy demand.…”