Necrostatin-1 reduces cardiac and mitochondrial dysfunction in prediabetic rats

Abstract

High fat diet (HFD) consumption induces prediabetes and left ventricular dysfunction through many pathways including the cell death pathway, necroptosis. Although benefits of necroptosis inhibitor (necrostatin-1 or Nec-1) in the brain of prediabetic rats have been shown, the effects of Nec-1 on cardiac autonomic function, blood pressure, and cardiac function, and the mechanisms involved have not been investigated. Male Wistar rats were fed with either a normal diet (n=8) or HFD (n=24) for 12 weeks to induce prediabetes. Prediabetic rats were randomly assigned into 3 interventional groups (n=8/group): 1) vehicle, 2) Nec-1 (1.65 mg/kg, sc injection), and 3) metformin (300 mg/kg, oral gavage feeding). Treatments lasted for 8 weeks. Normal saline was given to the vehicle group and a non-interventional group. Metabolic parameters, cardiac function and biochemical parameters were assessed. Prediabetic rats exhibited peripheral metabolic impairment as indicated by increased body weight, hyperinsulinemia with euglycemia, and dyslipidemia. Prediabetic rats also exhibited cardiac autonomic imbalance, high blood pressure, cardiac dysfunction, cardiac mitochondrial dysfunction, mitochondrial dynamic imbalance, and increased necroptosis and apoptosis. Treatment with Nec-1 did not affect peripheral metabolic parameters, however it effectively reduced cardiac autonomic imbalance, blood pressure, and cardiac dysfunction via reduced cardiac inflammation, necroptosis, mitochondrial dysfunction, and increased mitochondrial fusion. Treatment with metformin reduced peripheral metabolic impairment and cardiac dysfunction via decreased cardiac mitochondrial dysfunction, mitochondrial dynamic imbalance, and apoptosis. In summary, Nec-1 directly suppressed necroptosis, cardiac mitochondrial dysfunction, and increased mitochondrial fusion independent to peripheral metabolic function, leading to an improvement in cardiac function in prediabetic rats.

MLKL-mediated necroptosis is a target for cardiac protection in mouse models of type-1 diabetes

“…These in vitro studies have engaged the necroptosis signaling in high glucose-induced cardiomyocyte death. In animal models of diabetes including STZ injection-induced type-1 diabetic mice [ 27 ], high fat diet-induced pre-diabetic rats [ 25 ], high fat diet plus STZ-induced type-2 diabetic rats [ 43 ] and db/db type-2 diabetic mice [ 27 ], the protein levels of total and/or phosphorylated RIPK1/RIPK3/MLKL were elevated in the heart, suggesting a potential role of necroptosis in cardiac complications of diabetes. Indeed, this was supported by a most recent study which showed that deletion of RIPK3 alleviated myocardial injury and dysfunction in STZ-injected mice [ 27 ].…”

“…Although activation of RIPK3 and MLKL necroptosis signaling has recently been reported in diabetic hearts [22][23][24][25][26][27], direct evidence of cardiomyocyte necroptosis is lacking in the heart. To characterize cardiomyocyte necroptosis in the heart in situ, we first determined necrosis in the hearts of STZ-induced type-1 diabetic mice.…”

“…RIPK3 then phosphorylates MLKL, which allows its recruitment to the inner cell membrane to form a lethal pore, inducing membrane rupture [18][19][20][21]. It has been recently reported that RIPK3 and MLKL necroptosis signaling is activated in cardiomyocytes and hearts under diabetic conditions [22][23][24][25][26]. A recent study showed that deletion of RIPK3 attenuated serum makers of myocardial injury and heart dysfunction in streptozocin (STZ)-induced diabetic mice [27].…”

Necroptosis in CNS diseases: Focus on astrocytes

“…There were studies conducted on the potential therapeutic effect of Nec-1 in many diseases affecting all organ systems. Briefly, the neuroprotective effect of necrostatin in ischemic injuries (Liu et al, 2019a;Mitroshina et al, 2022), hydrocephalus (Liu et al, 2021a), mitochondrial dysfunction (Apaijai et al, 2021), intracranial hypertension (Qian et al, 2022) was revealed. Necrostatin reduces postoperative cognitive dysfunction (Yin et al, 2022), neonatal neurotoxicity (Xu et al, 2021b), and cardiotoxicity (Erdogmus Ozgen et al, 2022).…”

The Role of Mitochondrial Abnormalities in Diabetic Cardiomyopathy

“…Similarly to Mfn2 over-expression, treatment of HFD-induced prediabetic mice with necrostatin-1, an inhibitor of cell death and inflammation receptor RIPK1, with known cardioprotective properties [ 41 ], effectively enhanced Mfn2 protein levels, with no alterations in Mfn1 and Opa1 protein levels, thus increasing mitochondrial fusion and alleviating mitochondrial dysfunction. In addition, necrostatin-1 effectively reduced cardiac dysfunction, cardiac autonomic imbalance, and blood pressure in prediabetic rats [ 42 ].…”