Diabetes aggravates myocardial ischaemia reperfusion injury via activating Nox2‐related programmed cell death in an AMPK‐dependent manner

Abstract

Cardiovascular diseases such as myocardial ischaemia have a high fatality rate in patients with diabetes. This study was designed to expose the crosstalk between oxidative stress and AMPK, a vital molecule that controls biological energy metabolism, in myocardial ischaemia reperfusion injury (I/RI) in diabetic rats. Diabetes was stimulated in rats using streptozotocin injection. Rats were separated on random into control, control + I/R, Diabetes, Diabetes + I/R, Diabetes + I/R + N-acetylcysteine and Diabetes + I/R + Vas2870 groups. Myocardial infarct size was determined, and the predominant Nox family isoforms were analysed. In vitro, the H9C2 cells were administered excess glucose and exposed to hypoxia/reoxygenation to mimic diabetes and I/R. The AMPK siRNA or AICAR was used to inhibit or activate AMPK expression in H9C2 cells, respectively. Then, myocardial oxidative stress and programmed cell death were measured. Diabetes or high glucose levels were found to aggravate myocardial I/RI or hypoxia/reoxygenation in H9C2 cells, as demonstrated by an increase in myocardial infarct size or lactate dehydrogenase levels, oxidative stress generation and induction of programmed cell death. In diabetic rat hearts, cardiac Nox1, Nox2 and Nox4 were all heightened. The suppression of Nox2 expression using Vas2870 or Nox2-siRNA treatment in vivo or in vitro, respectively, protected diabetic rats from myocardial I/RI. AMPK gene knockout increased Nox2 protein expression while AMPK agonist decreased Nox2 expression. Therefore, diabetes aggravates myocardial I/RI by generating of Nox2-associated oxidative stress in an AMPK-dependent manner, which led to the induction of programmed cell death such as apoptosis, pyroptosis and ferroptosis.

The Molecular Mechanisms of Iron Metabolism and Its Role in Cardiac Dysfunction and Cardioprotection

“…Other interventions with anti-ferroptotic effects include activation of mTOR [ 149 ] and inhibition of HO-1, causing heme degradation with resultant release of free iron (inhibitor zinc protoporphyrin IX) [ 77 , 151 , 154 ], as well as other lipid peroxidation inhibitors (liproxstatin-1) [ 129 ]. In summary, these findings concerning ferroptosis confirm a paradigm of an important role of nonapoptotic cell death in the heart [ 130 , 155 , 156 , 157 ] and indicate that pharmacological interventions targeting one of these necrotic-like cell death modes or multi-target approaches can affect cardiovascular mortality at a greater extent than it is in the case of caspase modulation. This is also supported by the evidence showing that ferroptosis can accompany necroptosis and pyroptosis in the heart [ 130 , 157 ].…”

“…In summary, these findings concerning ferroptosis confirm a paradigm of an important role of nonapoptotic cell death in the heart [ 130 , 155 , 156 , 157 ] and indicate that pharmacological interventions targeting one of these necrotic-like cell death modes or multi-target approaches can affect cardiovascular mortality at a greater extent than it is in the case of caspase modulation. This is also supported by the evidence showing that ferroptosis can accompany necroptosis and pyroptosis in the heart [ 130 , 157 ].…”

“…Ferroptosis, known as simultaneously occurring and mutually amplifying accumulation of redox-active iron, glutathione depletion, and lipid peroxidation [ 127 ], was identified in 2012 [ 128 ] and since that time it has been documented in several cardiac pathologies, including doxorubicin-induced cardiomyopathy [ 77 ] and acute I/R injury under conditions without metabolic disorders [ 77 , 129 ] as well as with diabetes [ 130 , 131 ], post-myocardial infarction heart failure in the early and middle stages [ 132 ], and in septic heart injury [ 133 ]. At a cellular level, ferroptosis has been found in various models of cardiomyocytes, such as H9c2 cells subjected to hypoxia/reoxygenation with normal and high glucose levels [ 130 , 131 ] and rat ventricular myocytes [ 132 ].…”

“…As mentioned above, ferroptosis has been found to underlie lethal injury of the heart due to both acute and chronic I/R and in various types of cardiomyopathies [ 77 , 102 , 129 , 130 , 131 , 132 ]. In contrast, targeting ferroptosis has been suggested as a feasible approach for managing these cardiac pathologies.…”

Metformin prevented high glucose-induced endothelial reactive oxygen species via OGG1 in an AMPKα-Lin-28 dependent pathway

“…Deletion of Nox1or treatment of diabetic ApoE-/- mice with GKT137831 significantly reduced the ability of leukocytes attached to the aortic wall, Macrophage infiltration and Aortic Nitrative and Oxidative Stress compared with diabetic ApoE-/- mice[39]. Additionally, post-hypoxic oxidative stress and programmed cell death in cardiomyocytes exposed to high glucose was attenuated by gene deletion of NOX2[40]. Downregulation of Nox4 by gene deletion of NOX4 in the rat kidney glomerular mesangial cells inhibited the HG-induced augment in mitochondrial superoxide assessed by MitoSOX Red.…”