Abstract
Diabetic nephropathy remains a major microvascular complication of diabetes and the most common cause of end-stage renal disease requiring dialysis in the USA. Medical advances over the past century have substantially improved the management of diabetes mellitus and thereby increased patient survival. However, current standards of care reduce but do not eliminate the risk of diabetic nephropathy, and future studies are required to further understand the molecular mechanisms involved in the pathogenesis of diabetic nephropathy. There is an increasing body of evidence indicating that reactive oxygen species (ROS) may play a major role in the development of diabetic nephropathy. Oxidative stress is increased in diabetes, and the overproduction of ROS correlates with complications of diabetes, including diabetic nephropathy. Both NADPH oxidase and mitochondrial electron gradients seem to play critical roles in hyperglycemia-induced ROS generation. However, the key pathways by which hyperglycemia leads to enhanced ROS and structural changes associated with diabetic nephropathy are not well established. It is known that in addition to their ability to directly inflict macromolecular damage, ROS can function as signaling molecules resulting in transcriptional activation of profibrotic genes in the kidney. Here, we highlight the role of ROS in the development of the diabetic kidney disease. In particular, we will discuss recent advances in our understanding of the molecular mechanisms by which mitochondrial ROS might be implicated in the pathogenesis and progression of diabetic nephropathy.
Access provided by Autonomous University of Puebla. Download reference work entry PDF
Similar content being viewed by others
Keywords
Introduction
Diabetes is a worldwide pandemic affecting approximately 160 million individuals as of the year 2000 and is expected to rise to 366 million individuals by 2030, an estimated 50 % increase over 30 years in the number of individuals with diabetes (Wild et al. 2004). Diabetic nephropathy is a major microvascular complication of diabetes, affecting between 20 % and 40 % of diabetic patients (Hasslacher et al. 1989). Of note, in 1975, 3 years after the initiation of the end-stage renal disease program, patients with diabetes mellitus comprised only ∼ 5 % of dialysis patients. However, in the intervening time, there has been an explosion in the incidence and prevalence of type 2 diabetes that has resulted in diabetes mellitus becoming the leading cause of end-stage renal disease (ESRD) in industrialized countries, including the USA (http://www.cdc.gov/diabetes/pubs/factsheet11.htm).
The mechanisms underlying the development and progression of diabetic nephropathy remain poorly understood; however, it is known that the level of hyperglycemia correlates with progression of diabetic nephropathy and retinopathy (Remuzzi and Ruggenenti 1993; Lewis et al. 1993), and improving glycemic control decreases the rate of progression of diabetic nephropathy and loss of kidney function (Lewis et al. 1993; 2003). The differential effect of chronic hyperglycemia on different tissues reflects the failure of cells to downregulate the uptake of glucose when extracellular glucose concentrations are elevated. Consistent with this notion, hyperglycemic damage is pronounced in cells and tissues which show no significant change in glucose transport rate, resulting in intracellular hyperglycemia and cell damage.
Although multiple recent published reviews have provided an excellent summary of the most popular pathways underlying hyperglycemia-induced diabetic cellular and kidney damage, the mechanisms leading to the development of diabetic nephropathy remain largely unknown. In general, it is believed that prolonged hyperglycemia leads to chronic metabolic and hemodynamic changes that modulate various intracellular signaling pathways, transcription factors, cytokines, chemokines, and growth factors (Soldatos and Cooper 2008; Remuzzi et al. 2002). These effects promote structural abnormalities in the kidney such as glomerular basement membrane thickening, podocyte injury, and mesangial matrix expansion with the later development of irreversible glomerular sclerosis and tubulointerstitial fibrosis associated with declining GFR.
Experimental evidence suggests that the critical molecular pathways that may be involved in the development of diabetic nephropathy include increased oxidant stress, enhanced flux into the polyol and hexosamine pathways, activation of PKC and transforming growth factor (TGF)-β-SMAD-MAPK signaling pathways, and increased formation of advanced glycation end products (AGEs). In addition, high glucose can activate the proinflammatory transcription factor NF-κB, resulting in increased inflammatory gene expression in part through oxidant stress, AGEs, PKC, and MAPKs (Schmid et al. 2006; Lee et al. 2004). Finally, hemodynamic changes, in part through the probable activation of the renin-angiotensin system (RAS) and VEGF signaling axis, also play critical roles in the pathobiology of diabetic nephropathy (Anderson and Brenner 1988; Hostetter et al. 1982; Khamaisi et al. 2003; Cooper et al. 1999). Although all of these factors have been implicated in the pathogenesis of diabetic nephropathy, here we focus on some of the new concepts highlighting the role of ROS in the pathogenesis and progression of diabetic kidney disease. This chapter will discuss a summary of the latest published data on the molecular mechanisms associated with the role of ROS in pathological changes in the kidney during the development of diabetic nephropathy.
Generation of Oxidative Stress in Diabetic Nephropathy
ROS include a number of molecular species derived from oxygen that arise principally from superoxide (O2 •−) (Sena and Chandel 2012). ROS can be produced enzymatically or nonenzymatically. Among several enzymes which have been implicated in the generation of ROS, cytoplasmic NADPH oxidases located mainly on the cell membrane of polymorphonuclear cells, macrophages and endothelial cells (Vignais 2002), and cytochrome P450-dependent oxygenases are well-characterized sources of enzymatic ROS (Coon et al. 1992). In contrast, the nonenzymatic production of superoxide mainly involves mitochondrial electron transport chain, which contains several redox centers that may leak electrons to oxygen, constituting the primary source of superoxide in most tissues.
It is now clear that various types of cells including endothelial, vascular smooth muscle, mesangial, and tubular epithelial cells are capable of producing ROS under hyperglycemic condition (Remuzzi et al. 2002), and there is increasing evidence that the overproduction of ROS is one major factor in the development of diabetic complications, including diabetic nephropathy. But how enhanced ROS lead to structural changes associated with diabetic kidney disease is less understood. Physiological levels of ROS are important in diverse biological activities of the cell, and small fluctuations in the steady-state concentration of ROS play a role in signal transduction cascades. However, uncontrolled increases in the steady-state concentrations of these oxidants are regarded as toxic by-products of metabolism that cause damage to cellular components, including proteins, lipids, carbohydrates, and DNA. Furthermore, in addition to their ability to directly inflict macromolecular damage, ROS can activate a number of cellular stress-sensitive pathways that cause cellular damage (Schmid et al. 2006). For instance, ROS mediate hyperglycemia-induced activation of signal transduction cascades and transcription factors leading to transcriptional activation of profibrotic genes (Lee et al. 2004). Protein kinase C (PKC), transforming growth factor-β1 (TGF-β1), and angiotensin II (Ang II) stimulated by hyperglycemia-induced ROS, in turn, generate and signal through ROS and thus ROS act as a signal amplifier in diabetes (Lee et al. 2004).
The glucose auto-oxidation, polyol pathway, AGE, mitochondrial electron transport chain (ETC), uncoupled eNOS, and NAD(P)H oxidases have been long considered as main sources of ROS generation in diabetes. Among all these potential sources of ROS generation in the diabetic kidney, we will, however, mainly focus on the roles of mitochondria and activated NADPH oxidase.
Mitochondrial ROS
Mitochondria are the main source of ROS within most mammalian cells, and it is generally believed that the majority of ROS in the mitochondria are by-products of mitochondrial respiration. The mitochondrial electron transport chain (ETC) contains several redox centers that may leak electrons to molecular oxygen, serving as the primary source of endogenous superoxide production (Andreyev et al. 2005; Turrens 2003a; Balaban et al. 2005). Indeed, two of the respiratory chain complexes (I and III) have been long recognized as important sources of superoxide production.
The mitochondria generate energy by oxidizing hydrogen derived from our dietary carbohydrates (TCA cycle) and fats (β-oxidation) with oxygen to generate heat and ATP. The production of ATP occurs in the mitochondrial inner membrane, in the ETC. Electron flow is carried out by four membrane-associated enzyme complexes (complexes I to IV), plus cytochrome c and the mobile carrier ubiquinone (QH2). In the mitochondrial matrix, two electrons donated from NADH to complex I (NADH dehydrogenase) or from succinate to complex II (succinate dehydrogenase, SDH) are passed sequentially to ubiquinone (coenzyme Q or CoQ) to give ubisemiquinone (CoQH•) and then ubiquinol (CoQH2). Ubiquinol transfers its electrons to complex III (ubiquinol:cytochrome c oxidoreductase), which transfers them to cytochrome c. From cytochrome c, the electrons flow to complex IV (cytochrome c oxidase or COX) and finally to1/2 O2 to give H2O. Each of these ETC complexes incorporates multiple electron carriers. Complexes I, II, and III encompass several iron-sulfur (Fe-S) centers, whereas complexes III and IV encompass the b + c1 and a + a3 cytochromes, respectively.
The energy released by the flow of electrons through the ETC is used to pump protons out of the mitochondrial inner membrane through complexes I, III, and IV. This creates an electrochemical gradient (−0.32 V to + 0.39 V) across the mitochondrial inner membrane, which is used for ATP synthesis by complex V (ATP synthase). As protons flow back into the matrix through a proton channel in complex V, ADP and Pi are bound, condensed, and released as ATP. Thus, the mitochondria generate most of the endogenous ROS as a by-product of OXPHOS.
ROS production is increased when excess electrons are provided to ETC. The excess electrons are transferred to oxygen, which is converted to superoxide and subsequently to hydrogen peroxide. The highest rate of ROS production occurs when the proton gradient is high and oxygen consumption (ATP demand) is low. Superoxide O2 •− is converted to H2O2 by mitochondrial matrix enzyme Mn superoxide dismutase (MnSOD, Sod2) or by the Cu/ZnSOD (Sod1), which is located in both the mitochondrial intermembrane space and the cytosol.
Complex I and III of the ETC are important sources of ROS due to the formation of semistable radicals during electron transfer (FMN• in complex I and QH• in complex III) from which an electron may be transferred to molecular O2, generating O2 •−. Approximately 0.1–0.2 % of the total mitochondrial oxygen consumption is due to O2 •− production under normal physiological conditions (St-Pierre et al. 2002). Although it was initially assumed that the production of superoxide under normal conditions did not have any beneficial function, more recent studies have implicated ROS as an important cellular signaling molecule. For example, mitochondrial superoxide is a key component of angiogenesis and hypoxia-inducible factor (HIF) signaling cascades (Connor et al. 2005; Guzy et al. 2005).
Some of the potential mechanisms related to diabetes-induced mitochondrial ROS production are depicted in Fig. 117.1. Intracellular glucose oxidation begins with glycolysis in the cytoplasm, which generates NADH and pyruvate. Pyruvate can be transported into the mitochondria, where it is oxidized by the TCA cycle to produce four molecules of NADH and one molecule of FADH2. In the diabetic milieu, there is an increased flow of the key substrates NADH and FADH2 to the respiratory chain, which overdrives the electron transport system in the mitochondria, resulting in increased superoxide anion production (Haidara et al. 2009; Palm et al. 2003; Nishikawa et al. 2000b).
Diabetes is associated with alterations in mitochondrial metabolism that result in both increased formation of ROS and failure of bioenergetics (Nishikawa et al. 2000a, b; Turrens 2003b). Mitochondrial dysfunction is a hallmark of diabetic nephropathy, and a central role for mitochondrial ROS in microvascular complications of diabetes has been proposed by several groups with multiple studies suggesting perturbations in mitochondria in both insulin-deficient and insulin-resistant states and in the related condition of obesity (Haidara et al. 2009; Palm et al. 2003; Brownlee 2001, 2003; Green et al. 2004; DeRubertis et al. 2004; Vincent et al. 2002; Kristal et al. 1997; Yamagishi et al. 2001; Giardino et al. 1996). It must be noted that the term “mitochondrial dysfunction” is poorly defined in the literature and evidence exists for a wide range of alterations in mitochondria, including changes in biogenesis, number, morphology, and dynamics, including fusion and fission.
Brownlee was the first to suggest that ROS produced by the mitochondrial ETC are the driving force in the pathogenesis of diabetic nephropathy. He proposed a “unifying mechanism” where several seemingly independent pathways, including protein kinase Cβ, aldose reductase, advanced glycation end products, and the hexosamine biosynthetic pathway, are activated by a single upstream event: mitochondrial overproduction of ROS (Nishikawa et al. 2000b; Brownlee 2001, 2003; Green et al. 2004; Vincent et al. 2002; Ishii et al. 1996; Inoguchi et al. 2003; Koya et al. 1997; Lee et al. 2003; Watts et al. 2002). Consistent with this hypothesis and with the critical role of ROS in microvascular complications of diabetes, normalization of the mitochondrial superoxide levels blocked three major pathways of hyperglycemia-induced injury (Palm et al. 2003; Brownlee 2001). The evidence for this model, however, comes mainly from experiments on cultured endothelial cells, where raising the glucose concentration from 5 to 30 mmol/l increased ROS production, as measured by the rate of oxidation of dichlorodihydrofluorescein (DCFH) to dichlorofluorescein (DCF) (Haidara et al. 2009; Palm et al. 2003; Green et al. 2004). DCF oxidation was blocked by inhibitors of mitochondrial pyruvate uptake and succinate dehydrogenase, but not by rotenone, a complex I inhibitor, suggesting that ROS generation at complex II may be important. One puzzling question in this observation is how the overexpression of mitochondrial manganese superoxide dismutase (MnSOD) prevented high glucose-induced DCFH oxidation (Green et al. 2004). DCFH is primarily sensitive to hydrogen peroxide, nitric oxide, or hydroxyl radicals, and it is not directly oxidized by superoxide. The overexpression of MnSOD should have converted the superoxide generated in the mitochondrial matrix to hydrogen peroxide (Fig. 117.1). Thus, MnSOD overexpression should have enhanced the DCF signal rather than abolishing it. A potential explanation for the effect of MnSOD overexpression is that MnSOD detoxifies superoxide into hydrogen peroxide within the mitochondrial matrix, preventing its escape into the cytosol. The hydrogen peroxide is then converted to water by glutathione peroxidase in the mitochondria. This finding suggests that the nature of the ROS being measured in these experiments remains uncertain. DCF oxidation was also blocked by inhibitors of mitochondrial pyruvate uptake and of succinate dehydrogenase, but not by rotenone, suggesting that reverse electron transport was not involved.
A recent publication examined whether mitochondria-targeted antioxidant would prevent progression of diabetic nephropathy in the Ins2(+/)(AkitaJ) mouse model (Akita mice) of type 1 diabetes (Chacko et al. 2010). To test this hypothesis, the authors administered a mitochondria-targeted ubiquinone (MitoQ) over a 12-week period and assessed tubular and glomerular function. MitoQ treatment improved tubular and glomerular function in the Ins2(+/)−(AkitaJ) mice. However, it did not have a significant effect on plasma creatinine levels, although it decreased urinary albumin levels to the same level as nondiabetic controls. Importantly, interstitial fibrosis and glomerular damage were significantly reduced in the treated animals. These results support the hypothesis that mitochondrial-targeted therapies may be beneficial in the treatment of diabetic nephropathy. Moreover, overexpression of catalytic antioxidants was shown to protect against diabetic injury. Craven et al. (2001a) demonstrated that diabetic mice transgenic for Cu/Zn SOD had significantly lower urinary albumin excretion, glomerular hypertrophy, and glomerular expression of TGF-β1 and collagen IV protein compared to non-transgenic mice. The same group also showed that overexpression of MnSOD suppresses increases in collagen accumulation induced by culture of mesangial cells in high glucose media (Craven et al. 2001b). Similarly, Du et al. showed that overexpression of MnSOD in bovine aortic endothelial cells prevented high glucose-induced activation of PKC, NK-κB, hexosamine, and advanced glycation end product (AGE) pathways (Du et al. 2003). Finally, Brezniceanu et al. demonstrated that renal catalase overexpression in db/db mice attenuated ROS generation, angiotensinogen, proapoptotic gene expression, and apoptosis in the kidneys of diabetic mice in vivo (Brezniceanu et al. 2007).
In a recent study, Wang et al. have convincingly shown that changes in the mitochondrial dynamics contribute to increased mitochondrial ROS and progression of diabetic nephropathy (Wang et al. 2012). Mitochondria are dynamic organelles, which are able to interchange their morphology between elongated interconnected mitochondrial networks and a fragmented disconnected arrangement. The dynamic nature of mitochondrial networks is due to two opposing processes, mitochondrial fission and fusion, that operate concurrently (Chan 2006). Mitochondrial fission and fusion are crucial for maintaining mitochondrial function and are thought to be important for rapid repair of damaged mitochondria and for intermixing of DNA and proteins between mitochondria (Fig. 117.2).
A growing number of studies have begun to investigate changes in mitochondrial morphology and dynamics as important parameters for many disease-related processes. Importantly, changes in mitochondrial morphology and increased mitochondrial fission have been recently implicated in the progression of Huntington’s and Alzheimer’s disease (Chen and Chan 2009). Our group has recently investigated the role of mitochondrial dynamics and specifically mitochondrial fission in the context of diabetic nephropathy (Wang et al. 2012). Condensed fragmented mitochondria were observed in the podocytes in kidneys from diabetic mice, which were associated with changes in phosphorylation status of the mitochondrial fission protein Drp1 (dyanmin-related protein-1).
So how does hyperglycemia trigger mitochondrial fission and fragmentation leading to increased ROS and apoptosis in podocytes? Drp1 (dyanmin-related protein-1) is one of the most relevant genes identified to date that directly mediate mitochondrial fission. Drp1 is a soluble dynamin-related GTPase which is localized predominantly in the cytosol and must be recruited to mitochondria for fission to occur (Chan 2006; Chen and Chan 2009; De Vos et al. 2005). Current evidence suggests that Drp1 promotes fission by tethering to mitochondria at specific positions known as constriction sites. Drp1 then forms multimeric spirals around mitochondria further constricting mitochondrial tubules leading to mitochondrial fission (Smirnova et al. 2001).
The study by Wang et al. demonstrated that Drp1 is phosphorylated by high glucose-induced Rho kinase (ROCK1) activation, where this modification promotes the activity of Drp1, triggering its translocation from the cytosol to mitochondria, thus increasing fission. Whether inhibiting mitochondrial fission and Drp1 phosphorylation in the setting of DN would be beneficial is still unclear. However, consistent with these preclinical data, biopsies of skeletal muscle from subjects with type 2 diabetes reveal mitochondria of smaller size and number compared with control subjects (Kelley et al. 2002). Moreover, mitochondria of offspring of diabetic subjects are lower in density compared with those of controls (Morino et al. 2005).
Further evidence on the role of ROS in the development of diabetic nephropathy comes from studies on the potential role of uncoupling proteins on diabetic complications. Friederich et al. (2008) showed that diabetic rats express increased mitochondrial uncoupling protein-2 (UCP2) in proximal tubular cells associated with increased oxygen use and suggested that the increase in UCP2 was protective against oxidative stress. Manabe et al. (2008) reported that high glucose increased ROS fluorescence in human mesangial cells associated with potentially harmful cytokine expression, an effect that was blocked by astaxanthin, a carotenoid that accumulated in mitochondria. High glucose also reportedly increased H2O2 production by dichlorodihydrofluorescein fluorescence in human mesangial cells (Kiritoshi et al. 2003). This was suppressed by reduction in membrane potential by chemical inhibition or by UCP1 overexpression. Coughlan et al. (2007) demonstrated renal mitochondrial oxidative damage in streptozotocin-induced diabetic rats manifest as lucigenin luminescence in kidney slices, an effect that was reduced by alagebrium, a cross-link inhibitor of advanced glycosylation end product (AGE) accumulation. In another report, methylglyoxal formation (a precursor to AGEs) accompanied an increase in superoxide production by renal cortical mitochondria of 12-month STZ-diabetic rats (Rosca et al. 2005). Mitochondrial ROS also were implicated in renal pathology in the Goto-Kakizaki rat, a rodent model of type 2 diabetes (Rosen and Wiernsperger 2006). This study showed a reduction in tissue aconitase activity, a mitochondrial enzyme susceptible to inactivation by reactive oxygen, along with an increase in lipid peroxides.
In summary, the mitochondrial respiratory chain constitutes the main intracellular source of ROS in most tissues. Mitochondria, by virtue of numbers or functional properties or both, are critically involved in the pathophysiology of diabetes. The steady-state concentrations of ROS are maintained at nontoxic levels by a variety of antioxidant defenses and repair enzymes. This delicate balance between antioxidant defenses and ROS production may play a critical role in diabetic nephropathy in which the resulting oxidative insult could eventually cause kidney damage. New diabetes-treatment strategies are needed to address both mitochondrial function and ROS production. Pharmacologic interventions must focus on mechanisms regulating mitochondrial biogenesis, ROS, and respiration. Future examination of the members of the fission and fusion machinery may also enhance our understanding of the role of the mitochondrial dynamics in diabetic nephropathy. At the functional level, effective pharmacologic agents are needed that can be safely delivered to targeted sites within cells and within mitochondria.
NADPH Oxidase
NADPH oxidase is a multiprotein cytosolic enzyme complex initially identified in phagocytes, which generate ROS in response to bacterial infections. It catalyzes the transfer of electrons from NADPH to molecular oxygen via their catalytic subunits to generate superoxide. NADPH oxidase in phagocytic cells releases ROS as a defense against pathogens, whereas in endothelial cells (ECs), NADPH oxidase isoforms expressed in the endoplasmic reticulum (ER) and perinuclear membranes generate ROS as modulators of redox-sensitive signaling pathways.
How does NADPH oxidase generate ROS? NADPH oxidase is a heme-containing protein complex whose backbone is a Nox protein (also known as gp91phox). The Nox family is composed of 7 catalytic subunits termed Nox1-5 and Duox1 and Duox2 (for Dual Oxidase), regulatory subunits p22phox, p47phox, Noxo1, p67phox, Noxa1, p40phox, and the major binding partner Rac (Lambeth et al. 2000; Lambeth 2004). The enzyme is normally dormant in resting state but is rapidly activated upon appropriate stimulation in a process involving the translocation and association of cytoplasmic subunits. The activated cytoplasmic complex then associates with subunits in the membrane to form a functional enzyme with very specific regulatory mechanisms, tissue and subcellular patterns of expression, downstream targets, and functions.
The Nox isoforms are the catalytic subunits for ROS generation that are differentially expressed and regulated in various cell types but remain to be fully characterized. The reduced substrate NADPH binds to Nox isoforms on the cytoplasmic side of the membrane and releases two electrons, which are passed initially to FAD, then to the first and second heme groups, and finally accepted by two successive molecules of oxygen on the opposite side of the membrane, to produce two molecules of superoxide radical (Griendling and FitzGerald 2003a, b; Shiose et al. 2001; Jones et al. 1995; Radeke et al. 1991). In the kidney, all components of the NADPH oxidase complex, including p22phox, p47phox, and p67phox, as well as Nox isoforms 1, 2, and 4, are expressed, in a variety of cell types including fibroblasts, endothelial cells, vascular smooth muscle cells, mesangial cells, tubular cells, and podocytes.
An emerging body of evidence suggests that NADPH oxidase may play a pathogenic role in diabetic nephropathy. For instance, the mRNA expression of essential subunits of NADPH oxidase, NOX4 and p22phox, in the kidneys of streptozotocin-induced diabetic rats were markedly increased as compared with control rats (Etoh et al. 2003). Immunohistochemical analysis showed that the expression of Nox4 and p22phox were increased in both distal tubular cells and glomeruli. Insulin treatment for 2 weeks completely restored the levels of these components in the diabetic kidney to control levels. Moreover, pharmacological inhibition of NADPH oxidase with apocynin prevented upregulation of p47phox and gp91phox overexpression and retarded the mesangial matrix expansion seen in experimental diabetic nephropathy (Asaba et al. 2005; Thallas-Bonke et al. 2008). And finally, using antisense oligonucleotides for Nox4, Gorin et al. reported a significant improvement in renal hypertrophy and fibronectin accumulation in STZ rats (Gorin et al. 2005). These results suggest that the expression of NADPH oxidase subunits Nox4 and p22phox are upregulated in diabetic kidneys and that Nox4 may play a significant role in the pathogenesis of DN.
Several other reports have suggested that the expression of p22phox, p47phox, or p67phox are upregulated in the aorta from animal models of diabetes (Kim et al. 2002; Hink et al. 2001) and in the saphenous vein and internal mammary artery from patients with diabetes and coronary artery disease (Guzik et al. 2002). Furthermore, NADPH oxidase-driven superoxide production was reported to be involved in vascular dysfunction in a type 2 diabetes animal model (Kim et al. 2002). In addition, at least one report showed that the activity of NADPH oxidase was increased in the retina of diabetic rats, suggesting that NADPH might be involved in the development of diabetic retinopathy (Ellis et al. 2000).
One major gap in our current understanding of the role of NADPH oxidase in diabetic nephropathy is to identify the mechanisms underlying activation of NADPH oxidase. In this regard, it has been shown that NADPH oxidase is triggered by AGE (Soro-Paavonen et al. 2008; Wautier et al. 2001). Importantly, incubation of human endothelial cells with AGE (carboxymethyl lysine-modified adducts) promotes intracellular generation of ROS, which is suppressed by DPI and an AGE inhibitor but not by L-NAME. Furthermore, a soluble form of receptor for advanced glycation end products (sRAGE) significantly inhibits expression of NADPH oxidase in diabetic mice (Soro-Paavonen et al. 2008; Wautier et al. 2001).
Finally, activation of NADPH oxidase is abolished in diabetic PKCβ−/− mice, suggesting that NADPH oxidase is also activated via a PKC-dependent pathway (Ohshiro et al. 2006). Lack of PKCβ can protect against diabetes-induced renal dysfunction, fibrosis, and Nox-derived ROS production. Other PKC isoforms have also been implicated in NADPH oxidase activation in diabetes, e.g., PKCα is downstream of AGE-RAGE and mediates ROS generation by NADPH oxidase in the kidney of diabetic rats (Thallas-Bonke et al. 2008); PKCδ is responsible for high glucose-induced intracellular ROS production by NADPH oxidase in the adipocytes of diabetic mice (Taylor et al. 2005), while PKCζ is required for ROS generation from NADPH oxidase in mesangial cells treated with high glucose (Kwan et al. 2005). Angiotensin II is a potent stimulator of NADPH oxidase O2 •− production in the vasculature. Accordingly, inhibitors of angiotensin II signaling slow the progression of diabetic complications such as nephropathy, retinopathy, and atherosclerosis, independent of their ability to lower blood pressure in both type 1 and type 2 diabetes (Wei et al. 2007).
Taken together, multiple studies have shown that activation of NADPH oxidase affects both cellular redox signaling and oxidative stress in diabetes. Recent advances in the identification of vascular NADPH oxidase subunits, their subcellular localization/regulation, and feedback inhibition of NADPH oxidase via the Nrf2/ARE pathway provide novel therapeutic targets to combat oxidative stress in diabetes. Therefore, strategies to restore basal NADPH oxidase activity offer a potential scope of treatment.
Conclusions
While progression to diabetic nephropathy cannot yet be prevented, multiple observations suggest that increased oxidative stress in the kidney may have a fundamental role in the development of microvascular complications of diabetes. However, these observations need to be evaluated cautiously since the evidence on the potential role of ROS in the development of diabetic kidney disease is mainly supported in experimental models. This is of particular interest since experimental rodent models of diabetes may not recapitulate many key aspects of phenotypes observed in patients with diabetic nephropathy. Indeed, conventional antioxidants such as vitamin E have shown little benefit on progression of diabetic kidney disease. Future studies are needed to translate into therapeutics the potential role of ROS in the pathogenesis and development of diabetic nephropathy in patients with this devastating disease.
References
Anderson S, Brenner BM (1988) Pathogenesis of diabetic glomerulopathy: hemodynamic considerations. Diabetes Metab Rev 4:163–177
Andreyev AY, Kushnareva YE, Starkov AA (2005) Mitochondrial metabolism of reactive oxygen species. Biochemistry (Mosc) 70:200–214
Asaba K, Tojo A, Onozato ML, Goto A, Quinn MT, Fujita T, Wilcox CS (2005) Effects of NADPH oxidase inhibitor in diabetic nephropathy. Kidney Int 67:1890–1898
Balaban RS, Nemoto S, Finkel T (2005) Mitochondria, oxidants, and aging. Cell 120:483–495
Brezniceanu ML, Liu F, Wei CC, Tran S, Sachetelli S, Zhang SL, Guo DF, Filep JG, Ingelfinger JR, Chan JS (2007) Catalase overexpression attenuates angiotensinogen expression and apoptosis in diabetic mice. Kidney Int 71:912–923
Brownlee M (2001) Biochemistry and molecular cell biology of diabetic complications. Nature 414:813–820
Brownlee M (2003) A radical explanation for glucose-induced beta cell dysfunction. J Clin Invest 112:1788–1790
Chacko BK, Reily C, Srivastava A, Johnson MS, Ye Y, Ulasova E, Agarwal A, Zinn KR, Murphy MP, Kalyanaraman B et al (2010) Prevention of diabetic nephropathy in Ins2(+/)(AkitaJ) mice by the mitochondria-targeted therapy MitoQ. Biochem J 432:9–19
Chan DC (2006) Mitochondrial fusion and fission in mammals. Annu Rev Cell Dev Biol 22:79–99
Chen H, Chan DC (2009) Mitochondrial dynamics–fusion, fission, movement, and mitophagy–in neurodegenerative diseases. Hum Mol Genet 18:R169–R176
Connor KM, Subbaram S, Regan KJ, Nelson KK, Mazurkiewicz JE, Bartholomew PJ, Aplin AE, Tai YT, Aguirre-Ghiso J, Flores SC et al (2005) Mitochondrial H2O2 regulates the angiogenic phenotype via PTEN oxidation. J Biol Chem 280:16916–16924
Coon MJ, Ding XX, Pernecky SJ, Vaz AD (1992) Cytochrome P450: progress and predictions. FASEB J 6:669–673
Cooper ME, Vranes D, Youssef S, Stacker SA, Cox AJ, Rizkalla B, Casley DJ, Bach LA, Kelly DJ, Gilbert RE (1999) Increased renal expression of vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 in experimental diabetes. Diabetes 48:2229–2239
Coughlan MT, Thallas-Bonke V, Pete J, Long DM, Gasser A, Tong DC, Arnstein M, Thorpe SR, Cooper ME, Forbes JM (2007) Combination therapy with the advanced glycation end product cross-link breaker, alagebrium, and angiotensin converting enzyme inhibitors in diabetes: synergy or redundancy? Endocrinology 148:886–895
Craven PA, Melhem MF, Phillips SL, DeRubertis FR (2001a) Overexpression of Cu2+/Zn2+ superoxide dismutase protects against early diabetic glomerular injury in transgenic mice. Diabetes 50:2114–2125
Craven PA, Phillips SL, Melhem MF, Liachenko J, DeRubertis FR (2001b) Overexpression of manganese superoxide dismutase suppresses increases in collagen accumulation induced by culture of mesangial cells in high-media glucose. Metabolism 50:1043–1048
De Vos KJ, Allan VJ, Grierson AJ, Sheetz MP (2005) Mitochondrial function and actin regulate dynamin-related protein 1-dependent mitochondrial fission. Curr Biol 15:678–683
DeRubertis FR, Craven PA, Melhem MF, Salah EM (2004) Attenuation of renal injury in db/db mice overexpressing superoxide dismutase: evidence for reduced superoxide-nitric oxide interaction. Diabetes 53:762–768
Du X, Matsumura T, Edelstein D, Rossetti L, Zsengeller Z, Szabo C, Brownlee M (2003) Inhibition of GAPDH activity by poly(ADP-ribose) polymerase activates three major pathways of hyperglycemic damage in endothelial cells. J Clin Invest 112:1049–1057
Ellis EA, Guberski DL, Somogyi-Mann M, Grant MB (2000) Increased H2O2, vascular endothelial growth factor and receptors in the retina of the BBZ/WOR diabetic rat. Free Radic Biol Med 28:91–101
Etoh T, Inoguchi T, Kakimoto M, Sonoda N, Kobayashi K, Kuroda J, Sumimoto H, Nawata H (2003) Increased expression of NAD(P)H oxidase subunits, NOX4 and p22phox, in the kidney of streptozotocin-induced diabetic rats and its reversibity by interventive insulin treatment. Diabetologia 46:1428–1437
Friederich M, Fasching A, Hansell P, Nordquist L, Palm F (2008) Diabetes-induced up-regulation of uncoupling protein-2 results in increased mitochondrial uncoupling in kidney proximal tubular cells. Biochim Biophys Acta 1777:935–940
Giardino I, Edelstein D, Brownlee M (1996) BCL-2 expression or antioxidants prevent hyperglycemia-induced formation of intracellular advanced glycation endproducts in bovine endothelial cells. J Clin Invest 97:1422–1428
Gorin Y, Block K, Hernandez J, Bhandari B, Wagner B, Barnes JL, Abboud HE (2005) Nox4 NAD(P)H oxidase mediates hypertrophy and fibronectin expression in the diabetic kidney. J Biol Chem 280:39616–39626
Green K, Brand MD, Murphy MP (2004) Prevention of mitochondrial oxidative damage as a therapeutic strategy in diabetes. Diabetes 53:S110–S118
Griendling KK, FitzGerald GA (2003a) Oxidative stress and cardiovascular injury: part I: basic mechanisms and in vivo monitoring of ROS. Circulation 108:1912–1916
Griendling KK, FitzGerald GA (2003b) Oxidative stress and cardiovascular injury: part II: animal and human studies. Circulation 108:2034–2040
Guzik TJ, Mussa S, Gastaldi D, Sadowski J, Ratnatunga C, Pillai R, Channon KM (2002) Mechanisms of increased vascular superoxide production in human diabetes mellitus: role of NAD(P)H oxidase and endothelial nitric oxide synthase. Circulation 105:1656–1662
Guzy RD, Hoyos B, Robin E, Chen H, Liu L, Mansfield KD, Simon MC, Hammerling U, Schumacker PT (2005) Mitochondrial complex III is required for hypoxia-induced ROS production and cellular oxygen sensing. Cell Metab 1:401–408
Haidara MA, Mikhailidis DP, Rateb MA, Ahmed ZA, Yassin HZ, Ibrahim IM, Rashed LA (2009) Evaluation of the effect of oxidative stress and vitamin E supplementation on renal function in rats with streptozotocin-induced type 1 diabetes. J Diabetes Complications 23:130–136
Hasslacher C, Ritz E, Wahl P, Michael C (1989) Similar risks of nephropathy in patients with type I or type II diabetes mellitus. Nephrol Dial Transplant 4:859–863
Hink U, Li H, Mollnau H, Oelze M, Matheis E, Hartmann M, Skatchkov M, Thaiss F, Stahl RAK, Warnholtz A et al (2001) Mechanisms underlying endothelial dysfunction in diabetes mellitus. Circ Res 88:14e–22e
Hostetter TH, Rennke HG, Brenner BM (1982) The case for intrarenal hypertension in the initiation and progression of diabetic and other glomerulopathies. Am J Med 72:375–380
Inoguchi T, Sonta T, Tsubouchi H, Etoh T, Kakimoto M, Sonoda N, Sato N, Sekiguchi N, Kobayashi K, Sumimoto H et al (2003) Protein kinase C-dependent increase in reactive oxygen species (ROS) production in vascular tissues of diabetes: role of vascular NAD(P)H oxidase. J Am Soc Nephrol 14:S227–S232
Ishii H, Jirousek MR, Koya D, Takagi C, Xia P, Clermont A, Bursell S-E, Kern TS, Ballas LM, Heath WF et al (1996) Amelioration of vascular dysfunctions in diabetic rats by an oral PKC beta inhibitor. Science 272:728–731
Jones S, Hancock J, Jones O, Neubauer A, Topley N (1995) The expression of NADPH oxidase components in human glomerular mesangial cells: detection of protein and mRNA for p47phox, p67phox, and p22phox. J Am Soc Nephrol 5:1483–1491
Kelley DE, He J, Menshikova EV, Ritov VB (2002) Dysfunction of mitochondria in human skeletal muscle in type 2 diabetes. Diabetes 51:2944–2950
Khamaisi M, Schrijvers BF, De Vriese AS, Raz I, Flyvbjerg A (2003) The emerging role of VEGF in diabetic kidney disease. Nephrol Dial Transplant 18:1427–1430
Kim YK, Lee M-S, Son SM, Kim IJ, Lee WS, Rhim BY, Hong KW, Kim CD (2002) Vascular NADH oxidase is involved in impaired endothelium-dependent vasodilation in OLETF rats, a model of type 2 diabetes. Diabetes 51:522–527
Kiritoshi S, Nishikawa T, Sonoda K, Kukidome D, Senokuchi T, Matsuo T, Matsumura T, Tokunaga H, Brownlee M, Araki E (2003) Reactive oxygen species from mitochondria induce cyclooxygenase-2 gene expression in human mesangial cells: potential role in diabetic nephropathy. Diabetes 52:2570–2577
Koya D, Jirousek MR, Lin Y-W, Ishii H, Kuboki K, King GL (1997) Characterization of protein kinase C beta isoform activation on the gene expression of transforming growth factor-beta, extracellular matrix components, and prostanoids in the glomeruli of diabetic rats. J Clin Invest 100:115–126
Kristal BS, Jackson CT, Chung H-Y, Matsuda M, Nguyen HD, Yu BP (1997) Defects at center P underlie diabetes-associated mitochondrial dysfunction. Free Radic Biol Med 22:823–833
Kwan J, Wang H, Munk S, Xia L, Goldberg HJ, Whiteside CI (2005) In high glucose protein kinase C-zeta activation is required for mesangial cell generation of reactive oxygen species. Kidney Int 68:2526–2541
Lambeth JD (2004) Nox enzymes and the biology of reactive oxygen. Nat Rev Immunol 4:181–189
Lambeth JD, Cheng G, Arnold RS, Edens WA (2000) Novel homologs of gp91phox. Trends Biochem Sci 25:459–461
Lee HB, Yu M-R, Yang Y, Jiang Z, Ha H (2003) Reactive oxygen species-regulated signaling pathways in diabetic nephropathy. J Am Soc Nephrol 14:S241–S245
Lee FT, Cao Z, Long DM, Panagiotopoulos S, Jerums G, Cooper ME, Forbes JM (2004) Interactions between angiotensin II and NF-kappaB-dependent pathways in modulating macrophage infiltration in experimental diabetic nephropathy. J Am Soc Nephrol 15:2139–2151
Lewis EJ, Hunsicker LG, Bain RP, Rohde RD (1993) The effect of angiotensin-converting-enzyme inhibition on diabetic nephropathy. The Collaborative Study Group. N Engl J Med 329:1456–1462
Manabe E, Handa O, Naito Y, Mizushima K, Akagiri S, Adachi S, Takagi T, Kokura S, Maoka T, Yoshikawa T (2008) Astaxanthin protects mesangial cells from hyperglycemia-induced oxidative signaling. J Cell Biochem 103:1925–1937
Morino K, Petersen KF, Dufour S, Befroy D, Frattini J, Shatzkes N, Neschen S, White MF, Bilz S, Sono S et al (2005) Reduced mitochondrial density and increased IRS-1 serine phosphorylation in muscle of insulin-resistant offspring of type 2 diabetic parents. J Clin Invest 115:3587–3593
Nishikawa T, Edelstein D, Brownlee M (2000a) The missing link: a single unifying mechanism for diabetic complications. Kidney Int Suppl 77:S26–S30
Nishikawa T, Edelstein D, Du XL, Yamagishi S, Matsumura T, Kaneda Y, Yorek MA, Beebe D, Oates PJ, Hammes HP et al (2000b) Normalizing mitochondrial superoxide production blocks three pathways of hyperglycaemic damage. Nature 404:787–790
Ohshiro Y, Ma RC, Yasuda Y, Hiraoka-Yamamoto J, Clermont AC, Isshiki K, Yagi K, Arikawa E, Kern TS, King GL (2006) Reduction of diabetes-induced oxidative stress, fibrotic cytokine expression, and renal dysfunction in protein kinase Cbeta-null mice. Diabetes 55:3112–3120
Palm F, Cederberg J, Hansell P, Liss P, Carlsson PO (2003) Reactive oxygen species cause diabetes-induced decrease in renal oxygen tension. Diabetologia 46:1153–1160
Radeke H, Cross A, Hancock J, Jones O, Nakamura M, Kaever V, Resch K (1991) Functional expression of NADPH oxidase components (alpha- and beta- subunits of cytochrome b558 and 45-kDa flavoprotein) by intrinsic human glomerular mesangial cells. J Biol Chem 266:21025–21029
Remuzzi G, Ruggenenti P (1993) Slowing the progression of diabetic nephropathy. N Engl J Med 329:1496–1497
Remuzzi G, Schieppati A, Ruggenenti P (2002) Clinical practice. Nephropathy in patients with type 2 diabetes. N Engl J Med 346:1145–1151
Rosca MG, Mustata TG, Kinter MT, Ozdemir AM, Kern TS, Szweda LI, Brownlee M, Monnier VM, Weiss MF (2005) Glycation of mitochondrial proteins from diabetic rat kidney is associated with excess superoxide formation. Am J Physiol Renal Physiol 289:F420–F430
Rosen P, Wiernsperger NF (2006) Metformin delays the manifestation of diabetes and vascular dysfunction in Goto-Kakizaki rats by reduction of mitochondrial oxidative stress. Diabetes Metab Res Rev 22:323–330
Schmid H, Boucherot A, Yasuda Y, Henger A, Brunner B, Eichinger F, Nitsche A, Kiss E, Bleich M, Grone HJ et al (2006) Modular activation of nuclear factor-kappaB transcriptional programs in human diabetic nephropathy. Diabetes 55:2993–3003
Sena LA, Chandel NS (2012) Physiological roles of mitochondrial reactive oxygen species. Mol Cell 48:158–167
Shiose A, Kuroda J, Tsuruya K, Hirai M, Hirakata H, Naito S, Hattori M, Sakaki Y, Sumimoto H (2001) A novel superoxide-producing NAD(P)H oxidase in kidney. J Biol Chem 276:1417–1423
Smirnova E, Griparic L, Shurland DL, van der Bliek AM (2001) Dynamin-related protein Drp1 is required for mitochondrial division in mammalian cells. Mol Biol Cell 12:2245–2256
Soldatos G, Cooper ME (2008) Diabetic nephropathy: important pathophysiologic mechanisms. Diabetes Res Clin Pract 82:S75–S79
Soro-Paavonen A, Watson AM, Li J, Paavonen K, Koitka A, Calkin AC, Barit D, Coughlan MT, Drew BG, Lancaster GI et al (2008) Receptor for advanced glycation end products (RAGE) deficiency attenuates the development of atherosclerosis in diabetes. Diabetes 57:2461–2469
St-Pierre J, Buckingham JA, Roebuck SJ, Brand MD (2002) Topology of superoxide production from different sites in the mitochondrial electron transport chain. J Biol Chem 277:44784–44790
Taylor PD, McConnell J, Khan IY, Holemans K, Lawrence KM, Asare-Anane H, Persaud SJ, Jones PM, Petrie L, Hanson MA et al (2005) Impaired glucose homeostasis and mitochondrial abnormalities in offspring of rats fed a fat-rich diet in pregnancy. Am J Physiol Regul Integr Comp Physiol 288:R134–R139
Thallas-Bonke V, Thorpe SR, Coughlan MT, Fukami K, Yap FY, Sourris KC, Penfold SA, Bach LA, Cooper ME, Forbes JM (2008) Inhibition of NADPH oxidase prevents advanced glycation end product-mediated damage in diabetic nephropathy through a protein kinase C-alpha-dependent pathway. Diabetes 57:460–469
Turrens JF (2003a) Mitochondrial formation of reactive oxygen species. J Physiol 552:335–344
Turrens JF (2003b) Mitochondrial formation of reactive oxygen species. J Physiol (Lond) 552:335–344
Vignais PV (2002) The superoxide-generating NADPH oxidase: structural aspects and activation mechanism. Cell Mol Life Sci 59:1428–1459
Vincent AM, Brownlee M, Russell JW (2002) Oxidative stress and programmed cell death in diabetic neuropathy. Ann NY Acad Sci 959:368–383
Wang W, Wang Y, Long J, Wang J, Haudek SB, Overbeek P, Chang BH, Schumacker PT, Danesh FR (2012) Mitochondrial fission triggered by hyperglycemia is mediated by ROCK1 activation in podocytes and endothelial cells. Cell Metab 15:186–200
Watts G, Playford D, Croft K, Ward N, Mori T, Burke V (2002) Coenzyme Q(10) improves endothelial dysfunction of the brachial artery in type II diabetes mellitus. Diabetologia 45:420–426
Wautier MP, Chappey O, Corda S, Stern DM, Schmidt AM, Wautier JL (2001) Activation of NADPH oxidase by AGE links oxidant stress to altered gene expression via RAGE. Am J Physiol Endocrinol Metab 280:E685–E694
Wei Y, Whaley-Connell AT, Chen K, Habibi J, Uptergrove GM, Clark SE, Stump CS, Ferrario CM, Sowers JR (2007) NADPH oxidase contributes to vascular inflammation, insulin resistance, and remodeling in the transgenic (mRen2) rat. Hypertension 50:384–391
Wild S, Roglic G, Green A, Sicree R, King H (2004) Global prevalence of diabetes: estimates for the year 2000 and projections for 2030. Diabetes Care 27:1047–1053
Writing Team for the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Research Group. (2003) Sustained effect of intensive treatment of type 1 diabetes mellitus on development and progression of diabetic nephropathy: the Epidemiology of Diabetes Interventions and Complications (EDIC) study. JAMA 290:2159–2167
Yamagishi S-I, Edelstein D, Du X-L, Kaneda Y, Guzman M, Brownlee M (2001) Leptin induces mitochondrial superoxide production and monocyte Chemoattractant Protein-1 Expression in Aortic endothelial cells by increasing fatty acid oxidation via protein kinase A. J Biol Chem 276:25096–25100
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2014 Springer-Verlag Berlin Heidelberg
About this entry
Cite this entry
Badal, S.S., Badal, s.s., Danesh, F.R. (2014). Reactive Oxygen Species (ROS) and Diabetic Nephropathy. In: Laher, I. (eds) Systems Biology of Free Radicals and Antioxidants. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-30018-9_186
Download citation
DOI: https://doi.org/10.1007/978-3-642-30018-9_186
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-30017-2
Online ISBN: 978-3-642-30018-9
eBook Packages: Biomedical and Life SciencesReference Module Biomedical and Life Sciences