Canagliflozin ameliorates renal oxidative stress and inflammation by stimulating AMPK–Akt–eNOS pathway in the isoprenaline-induced oxidative stress model

Abstract

Diabetes is a leading cause of chronic kidney disease, and the high prevalence of sympathetic nervous system (SNS) hyperactivity in diabetic patients makes them further susceptible to SNS-mediated oxidative stress and accelerated kidney damage. Here, we investigated if canagliflozin can reverse isoprenaline (ISO)-induced renal oxidative damage in rats, a model that mimics SNS overstimulationinduced organ injuries in humans. We found that ISO administration elevates renal oxidative stress markers including malondialdehyde (MDA), advanced protein oxidation product (APOP), myeloperoxidase (MPO) and nitric oxide (NO), while depleting levels of endogenous antioxidants such as catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH). Strikingly, canagliflozin treatment of ISO-treated rats not only prevents elevation of oxidative stress markers but also rescues levels of depleted antioxidants. Our results also show that canagliflozin stimulates antioxidant/antiinflammatory signaling pathways involving AMP-activated protein kinase (AMPK), Akt and eNOS, and inhibits iNOS and NADPH oxidase isoform 4 (NOX4), all of which are associated with oxidative stress and inflammation. Further, canagliflozin prevents ISO-induced apoptosis of kidney cells by inhibiting Bax protein upregulation and caspase-3 activation. Histological examination of kidney sections reveal that canagliflozin attenuates ISO-mediated increases in inflammatory cell infiltration, collagen deposition and fibrosis. Finally, consistent with these findings, canagliflozin treatment improves kidney function in ISO-treated rats, suggesting that the antioxidant effects may be clinically translatable. Diabetic kidney disease is a major risk factor for the development of chronic kidney disease affecting approximately 40% of global diabetic population 1. Diabetic kidney disease is associated with vascular inflammation, loss of renal vascular integrity and hypertension, leading to a progressive loss of renovascular function and renal failure 1. Importantly, there is a high prevalence of sympathetic nervous system (SNS) hyperactivity in diabetic patients associated with autonomic neuropathy and concomitant vagal impairment, making diabetic patients twice as likely to develop hypertension 2. Diabetic patients are also highly susceptible to chronic kidney disease due to renal oxidative damage and inflammation 2. High SNS drive stimulates β1 adrenergic receptors (β1-AR) in juxtaglomerular cells, increasing renin secretion and subsequent activation of the renin-angiotensin-aldosterone system (RAAS). RAAS creates a feed-forward mechanism that accelerates renovascular dysfunction and kidney

Inhibition of oxidative stress and apoptosis by camel milk mitigates cyclosporine‐induced nephrotoxicity: Targeting Nrf2/HO‐1 and AKT/eNOS/NO pathways

“…Evolving lines of evidence have indicated that oxidative stress plays a crucial role in the pathogenesis of CsA‐induced nephrotoxicity (Abd‐Elhakim et al., 2020; Capasso et al., 2008; El‐Sheikh et al., 2019; Hasan et al., 2020). CsA has been reported to generate a surplus of ROS/free radicals due to its direct effect as uncoupler to the electron transport chain and during its metabolism by the cytochrome P450 3A enzyme (Origlia et al., 2006; Wu et al., 2018).…”

“…Equally important, CsA inactivated the anti‐apoptotic AKT/eNOS/NO pathway and lowered the renal content of NO. Classically, the AKT/eNOS/NO is an anti‐apoptotic pathway that advocates renal cell survival (Hasan et al., 2020; Havasi & Borkan, 2011). The observed inactivation of AKT/eNOS/NO pathway is compliant with the former literature that reported PI3K/AKT downregulation in response to superfluous ROS production (Guo et al., 2015; Hasan et al., 2020).…”

“…Classically, the AKT/eNOS/NO is an anti‐apoptotic pathway that advocates renal cell survival (Hasan et al., 2020; Havasi & Borkan, 2011). The observed inactivation of AKT/eNOS/NO pathway is compliant with the former literature that reported PI3K/AKT downregulation in response to superfluous ROS production (Guo et al., 2015; Hasan et al., 2020). Mechanistically, activated p‐AKT (Ser473) has been reported to instigate the phosphorylation and inactivation of Bax and Bad pro‐apoptotic signals (Hasan et al., 2020; Havasi & Borkan, 2011; Liu et al., 2020).…”

“…These findings agree with the reported anti‐apoptotic features of camel milk in diabetic lymphoid organs (Sayed et al., 2017), colitis, and toxicant‐induced renal pathologies (Arab et al., 2018a,b). Conceptually, modalities that can suppress the renal apoptotic cell death have been regarded as promising agents for favoring renal recovery and preserving kidney function (De Arriba et al., 2013; El‐Sheikh et al., 2019; Hasan et al., 2020; Havasi & Borkan, 2011). In this context, diverse antioxidant agents—such as erdosteine, schisandrin, apocynin, and spirulina—have been characterized as effective interventions against CsA‐evoked nephrotoxicity in rodents, a notion that coincides with the present study findings (Wu et al., 2018).…”

“…Notably, interventions that can activate the PI3K/AKT signaling have been reported to effectively dampen the apoptotic events and renal injury in several renal pathologies (Arab et al, 2018a,b; Liu et al., 2020). The PI3K/AKT pathway has been reported to counteract endothelial cell apoptosis via upregulation of endothelial nitric oxide synthase (eNOS) that generates the vasodilator nitric oxide (Hasan et al., 2020). Of note, the role of the PI3K/AKT pathway in the pathogenesis of CsA‐evoked renal injury has been inadequately investigated.…”